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Merge branch 'linux-next' of git://git.infradead.org/~dedekind/ubi-2.6

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3
CREDITS
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@ -3344,8 +3344,7 @@ S: Spain
N: Linus Torvalds
E: torvalds@linux-foundation.org
D: Original kernel hacker
S: 12725 SW Millikan Way, Suite 400
S: Beaverton, Oregon 97005
S: Portland, Oregon 97005
S: USA
N: Marcelo Tosatti

34
Documentation/ABI/testing/sysfs-block
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@ -26,3 +26,37 @@ Description:
I/O statistics of partition <part>. The format is the
same as the above-written /sys/block/<disk>/stat
format.
What: /sys/block/<disk>/integrity/format
Date: June 2008
Contact: Martin K. Petersen <martin.petersen@oracle.com>
Description:
Metadata format for integrity capable block device.
E.g. T10-DIF-TYPE1-CRC.
What: /sys/block/<disk>/integrity/read_verify
Date: June 2008
Contact: Martin K. Petersen <martin.petersen@oracle.com>
Description:
Indicates whether the block layer should verify the
integrity of read requests serviced by devices that
support sending integrity metadata.
What: /sys/block/<disk>/integrity/tag_size
Date: June 2008
Contact: Martin K. Petersen <martin.petersen@oracle.com>
Description:
Number of bytes of integrity tag space available per
512 bytes of data.
What: /sys/block/<disk>/integrity/write_generate
Date: June 2008
Contact: Martin K. Petersen <martin.petersen@oracle.com>
Description:
Indicates whether the block layer should automatically
generate checksums for write requests bound for
devices that support receiving integrity metadata.

35
Documentation/ABI/testing/sysfs-bus-css Normal file
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@ -0,0 +1,35 @@
What: /sys/bus/css/devices/.../type
Date: March 2008
Contact: Cornelia Huck <cornelia.huck@de.ibm.com>
linux-s390@vger.kernel.org
Description: Contains the subchannel type, as reported by the hardware.
This attribute is present for all subchannel types.
What: /sys/bus/css/devices/.../modalias
Date: March 2008
Contact: Cornelia Huck <cornelia.huck@de.ibm.com>
linux-s390@vger.kernel.org
Description: Contains the module alias as reported with uevents.
It is of the format css:t<type> and present for all
subchannel types.
What: /sys/bus/css/drivers/io_subchannel/.../chpids
Date: December 2002
Contact: Cornelia Huck <cornelia.huck@de.ibm.com>
linux-s390@vger.kernel.org
Description: Contains the ids of the channel paths used by this
subchannel, as reported by the channel subsystem
during subchannel recognition.
Note: This is an I/O-subchannel specific attribute.
Users: s390-tools, HAL
What: /sys/bus/css/drivers/io_subchannel/.../pimpampom
Date: December 2002
Contact: Cornelia Huck <cornelia.huck@de.ibm.com>
linux-s390@vger.kernel.org
Description: Contains the PIM/PAM/POM values, as reported by the
channel subsystem when last queried by the common I/O
layer (this implies that this attribute is not neccessarily
in sync with the values current in the channel subsystem).
Note: This is an I/O-subchannel specific attribute.
Users: s390-tools, HAL

20
Documentation/ABI/testing/sysfs-dev Normal file
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@ -0,0 +1,20 @@
What: /sys/dev
Date: April 2008
KernelVersion: 2.6.26
Contact: Dan Williams <dan.j.williams@intel.com>
Description: The /sys/dev tree provides a method to look up the sysfs
path for a device using the information returned from
stat(2). There are two directories, 'block' and 'char',
beneath /sys/dev containing symbolic links with names of
the form "<major>:<minor>". These links point to the
corresponding sysfs path for the given device.
Example:
$ readlink /sys/dev/block/8:32
../../block/sdc
Entries in /sys/dev/char and /sys/dev/block will be
dynamically created and destroyed as devices enter and
leave the system.
Users: mdadm <linux-raid@vger.kernel.org>

127
Documentation/ABI/testing/sysfs-firmware-acpi
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@ -29,46 +29,46 @@ Description:
$ cd /sys/firmware/acpi/interrupts
$ grep . *
error:0
ff_gbl_lock:0
ff_pmtimer:0
ff_pwr_btn:0
ff_rt_clk:0
ff_slp_btn:0
gpe00:0
gpe01:0
gpe02:0
gpe03:0
gpe04:0
gpe05:0
gpe06:0
gpe07:0
gpe08:0
gpe09:174
gpe0A:0
gpe0B:0
gpe0C:0
gpe0D:0
gpe0E:0
gpe0F:0
gpe10:0
gpe11:60
gpe12:0
gpe13:0
gpe14:0
gpe15:0
gpe16:0
gpe17:0
gpe18:0
gpe19:7
gpe1A:0
gpe1B:0
gpe1C:0
gpe1D:0
gpe1E:0
gpe1F:0
gpe_all:241
sci:241
error: 0
ff_gbl_lock: 0 enable
ff_pmtimer: 0 invalid
ff_pwr_btn: 0 enable
ff_rt_clk: 2 disable
ff_slp_btn: 0 invalid
gpe00: 0 invalid
gpe01: 0 enable
gpe02: 108 enable
gpe03: 0 invalid
gpe04: 0 invalid
gpe05: 0 invalid
gpe06: 0 enable
gpe07: 0 enable
gpe08: 0 invalid
gpe09: 0 invalid
gpe0A: 0 invalid
gpe0B: 0 invalid
gpe0C: 0 invalid
gpe0D: 0 invalid
gpe0E: 0 invalid
gpe0F: 0 invalid
gpe10: 0 invalid
gpe11: 0 invalid
gpe12: 0 invalid
gpe13: 0 invalid
gpe14: 0 invalid
gpe15: 0 invalid
gpe16: 0 invalid
gpe17: 1084 enable
gpe18: 0 enable
gpe19: 0 invalid
gpe1A: 0 invalid
gpe1B: 0 invalid
gpe1C: 0 invalid
gpe1D: 0 invalid
gpe1E: 0 invalid
gpe1F: 0 invalid
gpe_all: 1192
sci: 1194
sci - The total number of times the ACPI SCI
has claimed an interrupt.
@ -89,6 +89,13 @@ Description:
error - an interrupt that can't be accounted for above.
invalid: it's either a wakeup GPE or a GPE/Fixed Event that
doesn't have an event handler.
disable: the GPE/Fixed Event is valid but disabled.
enable: the GPE/Fixed Event is valid and enabled.
Root has permission to clear any of these counters. Eg.
# echo 0 > gpe11
@ -97,3 +104,43 @@ Description:
None of these counters has an effect on the function
of the system, they are simply statistics.
Besides this, user can also write specific strings to these files
to enable/disable/clear ACPI interrupts in user space, which can be
used to debug some ACPI interrupt storm issues.
Note that only writting to VALID GPE/Fixed Event is allowed,
i.e. user can only change the status of runtime GPE and
Fixed Event with event handler installed.
Let's take power button fixed event for example, please kill acpid
and other user space applications so that the machine won't shutdown
when pressing the power button.
# cat ff_pwr_btn
0
# press the power button for 3 times;
# cat ff_pwr_btn
3
# echo disable > ff_pwr_btn
# cat ff_pwr_btn
disable
# press the power button for 3 times;
# cat ff_pwr_btn
disable
# echo enable > ff_pwr_btn
# cat ff_pwr_btn
4
/*
* this is because the status bit is set even if the enable bit is cleared,
* and it triggers an ACPI fixed event when the enable bit is set again
*/
# press the power button for 3 times;
# cat ff_pwr_btn
7
# echo disable > ff_pwr_btn
# press the power button for 3 times;
# echo clear > ff_pwr_btn /* clear the status bit */
# echo disable > ff_pwr_btn
# cat ff_pwr_btn
7

71
Documentation/ABI/testing/sysfs-firmware-memmap Normal file
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@ -0,0 +1,71 @@
What: /sys/firmware/memmap/
Date: June 2008
Contact: Bernhard Walle <bwalle@suse.de>
Description:
On all platforms, the firmware provides a memory map which the
kernel reads. The resources from that memory map are registered
in the kernel resource tree and exposed to userspace via
/proc/iomem (together with other resources).
However, on most architectures that firmware-provided memory
map is modified afterwards by the kernel itself, either because
the kernel merges that memory map with other information or
just because the user overwrites that memory map via command
line.
kexec needs the raw firmware-provided memory map to setup the
parameter segment of the kernel that should be booted with
kexec. Also, the raw memory map is useful for debugging. For
that reason, /sys/firmware/memmap is an interface that provides
the raw memory map to userspace.
The structure is as follows: Under /sys/firmware/memmap there
are subdirectories with the number of the entry as their name:
/sys/firmware/memmap/0
/sys/firmware/memmap/1
/sys/firmware/memmap/2
/sys/firmware/memmap/3
...
The maximum depends on the number of memory map entries provided
by the firmware. The order is just the order that the firmware
provides.
Each directory contains three files:
start : The start address (as hexadecimal number with the
'0x' prefix).
end : The end address, inclusive (regardless whether the
firmware provides inclusive or exclusive ranges).
type : Type of the entry as string. See below for a list of
valid types.
So, for example:
/sys/firmware/memmap/0/start
/sys/firmware/memmap/0/end
/sys/firmware/memmap/0/type
/sys/firmware/memmap/1/start
...
Currently following types exist:
- System RAM
- ACPI Tables
- ACPI Non-volatile Storage
- reserved
Following shell snippet can be used to display that memory
map in a human-readable format:
-------------------- 8< ----------------------------------------
#!/bin/bash
cd /sys/firmware/memmap
for dir in * ; do
start=$(cat $dir/start)
end=$(cat $dir/end)
type=$(cat $dir/type)
printf "%016x-%016x (%s)\n" $start $[ $end +1] "$type"
done
-------------------- >8 ----------------------------------------

9
Documentation/DMA-attributes.txt
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@ -22,3 +22,12 @@ ready and available in memory. The DMA of the "completion indication"
could race with data DMA. Mapping the memory used for completion
indications with DMA_ATTR_WRITE_BARRIER would prevent the race.
DMA_ATTR_WEAK_ORDERING
----------------------
DMA_ATTR_WEAK_ORDERING specifies that reads and writes to the mapping
may be weakly ordered, that is that reads and writes may pass each other.
Since it is optional for platforms to implement DMA_ATTR_WEAK_ORDERING,
those that do not will simply ignore the attribute and exhibit default
behavior.

38
Documentation/DocBook/gadget.tmpl
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@ -524,6 +524,44 @@ These utilities include endpoint autoconfiguration.
<!-- !Edrivers/usb/gadget/epautoconf.c -->
</sect1>
<sect1 id="composite"><title>Composite Device Framework</title>
<para>The core API is sufficient for writing drivers for composite
USB devices (with more than one function in a given configuration),
and also multi-configuration devices (also more than one function,
but not necessarily sharing a given configuration).
There is however an optional framework which makes it easier to
reuse and combine functions.
</para>
<para>Devices using this framework provide a <emphasis>struct
usb_composite_driver</emphasis>, which in turn provides one or
more <emphasis>struct usb_configuration</emphasis> instances.
Each such configuration includes at least one
<emphasis>struct usb_function</emphasis>, which packages a user
visible role such as "network link" or "mass storage device".
Management functions may also exist, such as "Device Firmware
Upgrade".
</para>
!Iinclude/linux/usb/composite.h
!Edrivers/usb/gadget/composite.c
</sect1>
<sect1 id="functions"><title>Composite Device Functions</title>
<para>At this writing, a few of the current gadget drivers have
been converted to this framework.
Near-term plans include converting all of them, except for "gadgetfs".
</para>
!Edrivers/usb/gadget/f_acm.c
!Edrivers/usb/gadget/f_serial.c
</sect1>
</chapter>
<chapter id="controllers"><title>Peripheral Controller Drivers</title>

63
Documentation/DocBook/uio-howto.tmpl
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@ -21,6 +21,18 @@
</affiliation>
</author>
<copyright>
<year>2006-2008</year>
<holder>Hans-Jürgen Koch.</holder>
</copyright>
<legalnotice>
<para>
This documentation is Free Software licensed under the terms of the
GPL version 2.
</para>
</legalnotice>
<pubdate>2006-12-11</pubdate>
<abstract>
@ -29,6 +41,12 @@
</abstract>
<revhistory>
<revision>
<revnumber>0.5</revnumber>
<date>2008-05-22</date>
<authorinitials>hjk</authorinitials>
<revremark>Added description of write() function.</revremark>
</revision>
<revision>
<revnumber>0.4</revnumber>
<date>2007-11-26</date>
@ -57,20 +75,9 @@
</bookinfo>
<chapter id="aboutthisdoc">
<?dbhtml filename="about.html"?>
<?dbhtml filename="aboutthis.html"?>
<title>About this document</title>
<sect1 id="copyright">
<?dbhtml filename="copyright.html"?>
<title>Copyright and License</title>
<para>
Copyright (c) 2006 by Hans-Jürgen Koch.</para>
<para>
This documentation is Free Software licensed under the terms of the
GPL version 2.
</para>
</sect1>
<sect1 id="translations">
<?dbhtml filename="translations.html"?>
<title>Translations</title>
@ -189,6 +196,30 @@ interested in translating it, please email me
represents the total interrupt count. You can use this number
to figure out if you missed some interrupts.
</para>
<para>
For some hardware that has more than one interrupt source internally,
but not separate IRQ mask and status registers, there might be
situations where userspace cannot determine what the interrupt source
was if the kernel handler disables them by writing to the chip's IRQ
register. In such a case, the kernel has to disable the IRQ completely
to leave the chip's register untouched. Now the userspace part can
determine the cause of the interrupt, but it cannot re-enable
interrupts. Another cornercase is chips where re-enabling interrupts
is a read-modify-write operation to a combined IRQ status/acknowledge
register. This would be racy if a new interrupt occurred
simultaneously.
</para>
<para>
To address these problems, UIO also implements a write() function. It
is normally not used and can be ignored for hardware that has only a
single interrupt source or has separate IRQ mask and status registers.
If you need it, however, a write to <filename>/dev/uioX</filename>
will call the <function>irqcontrol()</function> function implemented
by the driver. You have to write a 32-bit value that is usually either
0 or 1 to disable or enable interrupts. If a driver does not implement
<function>irqcontrol()</function>, <function>write()</function> will
return with <varname>-ENOSYS</varname>.
</para>
<para>
To handle interrupts properly, your custom kernel module can
@ -362,6 +393,14 @@ device is actually used.
<function>open()</function>, you will probably also want a custom
<function>release()</function> function.
</para></listitem>
<listitem><para>
<varname>int (*irqcontrol)(struct uio_info *info, s32 irq_on)
</varname>: Optional. If you need to be able to enable or disable
interrupts from userspace by writing to <filename>/dev/uioX</filename>,
you can implement this function. The parameter <varname>irq_on</varname>
will be 0 to disable interrupts and 1 to enable them.
</para></listitem>
</itemizedlist>
<para>

4
Documentation/HOWTO
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@ -358,7 +358,7 @@ Here is a list of some of the different kernel trees available:
- pcmcia, Dominik Brodowski <linux@dominikbrodowski.net>
git.kernel.org:/pub/scm/linux/kernel/git/brodo/pcmcia-2.6.git
- SCSI, James Bottomley <James.Bottomley@SteelEye.com>
- SCSI, James Bottomley <James.Bottomley@hansenpartnership.com>
git.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6.git
- x86, Ingo Molnar <mingo@elte.hu>
@ -377,7 +377,7 @@ Bug Reporting
bugzilla.kernel.org is where the Linux kernel developers track kernel
bugs. Users are encouraged to report all bugs that they find in this
tool. For details on how to use the kernel bugzilla, please see:
http://test.kernel.org/bugzilla/faq.html
http://bugzilla.kernel.org/page.cgi?id=faq.html
The file REPORTING-BUGS in the main kernel source directory has a good
template for how to report a possible kernel bug, and details what kind

39
Documentation/IRQ-affinity.txt
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@ -1,17 +1,26 @@
ChangeLog:
Started by Ingo Molnar <mingo@redhat.com>
Update by Max Krasnyansky <maxk@qualcomm.com>
SMP IRQ affinity, started by Ingo Molnar <mingo@redhat.com>
SMP IRQ affinity
/proc/irq/IRQ#/smp_affinity specifies which target CPUs are permitted
for a given IRQ source. It's a bitmask of allowed CPUs. It's not allowed
to turn off all CPUs, and if an IRQ controller does not support IRQ
affinity then the value will not change from the default 0xffffffff.
Here is an example of restricting IRQ44 (eth1) to CPU0-3 then restricting
the IRQ to CPU4-7 (this is an 8-CPU SMP box):
/proc/irq/default_smp_affinity specifies default affinity mask that applies
to all non-active IRQs. Once IRQ is allocated/activated its affinity bitmask
will be set to the default mask. It can then be changed as described above.
Default mask is 0xffffffff.
Here is an example of restricting IRQ44 (eth1) to CPU0-3 then restricting
it to CPU4-7 (this is an 8-CPU SMP box):
[root@moon 44]# cd /proc/irq/44
[root@moon 44]# cat smp_affinity
ffffffff
[root@moon 44]# echo 0f > smp_affinity
[root@moon 44]# cat smp_affinity
0000000f
@ -21,17 +30,27 @@ PING hell (195.4.7.3): 56 data bytes
--- hell ping statistics ---
6029 packets transmitted, 6027 packets received, 0% packet loss
round-trip min/avg/max = 0.1/0.1/0.4 ms
[root@moon 44]# cat /proc/interrupts | grep 44:
44: 0 1785 1785 1783 1783 1
1 0 IO-APIC-level eth1
[root@moon 44]# cat /proc/interrupts | grep 'CPU\|44:'
CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7
44: 1068 1785 1785 1783 0 0 0 0 IO-APIC-level eth1
As can be seen from the line above IRQ44 was delivered only to the first four
processors (0-3).
Now lets restrict that IRQ to CPU(4-7).
[root@moon 44]# echo f0 > smp_affinity
[root@moon 44]# cat smp_affinity
000000f0
[root@moon 44]# ping -f h
PING hell (195.4.7.3): 56 data bytes
..
--- hell ping statistics ---
2779 packets transmitted, 2777 packets received, 0% packet loss
round-trip min/avg/max = 0.1/0.5/585.4 ms
[root@moon 44]# cat /proc/interrupts | grep 44:
44: 1068 1785 1785 1784 1784 1069 1070 1069 IO-APIC-level eth1
[root@moon 44]#
[root@moon 44]# cat /proc/interrupts | 'CPU\|44:'
CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7
44: 1068 1785 1785 1783 1784 1069 1070 1069 IO-APIC-level eth1
This time around IRQ44 was delivered only to the last four processors.
i.e counters for the CPU0-3 did not change.

3
Documentation/RCU/NMI-RCU.txt
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@ -93,6 +93,9 @@ Since NMI handlers disable preemption, synchronize_sched() is guaranteed
not to return until all ongoing NMI handlers exit. It is therefore safe
to free up the handler's data as soon as synchronize_sched() returns.
Important note: for this to work, the architecture in question must
invoke irq_enter() and irq_exit() on NMI entry and exit, respectively.
Answer to Quick Quiz

108
Documentation/RCU/RTFP.txt
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@ -52,6 +52,10 @@ of each iteration. Unfortunately, chaotic relaxation requires highly
structured data, such as the matrices used in scientific programs, and
is thus inapplicable to most data structures in operating-system kernels.
In 1992, Henry (now Alexia) Massalin completed a dissertation advising
parallel programmers to defer processing when feasible to simplify
synchronization. RCU makes extremely heavy use of this advice.
In 1993, Jacobson [Jacobson93] verbally described what is perhaps the
simplest deferred-free technique: simply waiting a fixed amount of time
before freeing blocks awaiting deferred free. Jacobson did not describe
@ -138,6 +142,13 @@ blocking in read-side critical sections appeared [PaulEMcKenney2006c],
Robert Olsson described an RCU-protected trie-hash combination
[RobertOlsson2006a].
2007 saw the journal version of the award-winning RCU paper from 2006
[ThomasEHart2007a], as well as a paper demonstrating use of Promela
and Spin to mechanically verify an optimization to Oleg Nesterov's
QRCU [PaulEMcKenney2007QRCUspin], a design document describing
preemptible RCU [PaulEMcKenney2007PreemptibleRCU], and the three-part
LWN "What is RCU?" series [PaulEMcKenney2007WhatIsRCUFundamentally,
PaulEMcKenney2008WhatIsRCUUsage, and PaulEMcKenney2008WhatIsRCUAPI].
Bibtex Entries
@ -202,6 +213,20 @@ Bibtex Entries
,Year="1991"
}
@phdthesis{HMassalinPhD
,author="H. Massalin"
,title="Synthesis: An Efficient Implementation of Fundamental Operating
System Services"
,school="Columbia University"
,address="New York, NY"
,year="1992"
,annotation="
Mondo optimizing compiler.
Wait-free stuff.
Good advice: defer work to avoid synchronization.
"
}
@unpublished{Jacobson93
,author="Van Jacobson"
,title="Avoid Read-Side Locking Via Delayed Free"
@ -635,3 +660,86 @@ Revised:
"
}
@unpublished{PaulEMcKenney2007PreemptibleRCU
,Author="Paul E. McKenney"
,Title="The design of preemptible read-copy-update"
,month="October"
,day="8"
,year="2007"
,note="Available:
\url{http://lwn.net/Articles/253651/}
[Viewed October 25, 2007]"
,annotation="
LWN article describing the design of preemptible RCU.
"
}
########################################################################
#
# "What is RCU?" LWN series.
#
@unpublished{PaulEMcKenney2007WhatIsRCUFundamentally
,Author="Paul E. McKenney and Jonathan Walpole"
,Title="What is {RCU}, Fundamentally?"
,month="December"
,day="17"
,year="2007"
,note="Available:
\url{http://lwn.net/Articles/262464/}
[Viewed December 27, 2007]"
,annotation="
Lays out the three basic components of RCU: (1) publish-subscribe,
(2) wait for pre-existing readers to complete, and (2) maintain
multiple versions.
"
}
@unpublished{PaulEMcKenney2008WhatIsRCUUsage
,Author="Paul E. McKenney"
,Title="What is {RCU}? Part 2: Usage"
,month="January"
,day="4"
,year="2008"
,note="Available:
\url{http://lwn.net/Articles/263130/}
[Viewed January 4, 2008]"
,annotation="
Lays out six uses of RCU:
1. RCU is a Reader-Writer Lock Replacement
2. RCU is a Restricted Reference-Counting Mechanism
3. RCU is a Bulk Reference-Counting Mechanism
4. RCU is a Poor Man's Garbage Collector
5. RCU is a Way of Providing Existence Guarantees
6. RCU is a Way of Waiting for Things to Finish
"
}
@unpublished{PaulEMcKenney2008WhatIsRCUAPI
,Author="Paul E. McKenney"
,Title="{RCU} part 3: the {RCU} {API}"
,month="January"
,day="17"
,year="2008"
,note="Available:
\url{http://lwn.net/Articles/264090/}
[Viewed January 10, 2008]"
,annotation="
Gives an overview of the Linux-kernel RCU API and a brief annotated RCU
bibliography.
"
}
@article{DinakarGuniguntala2008IBMSysJ
,author="D. Guniguntala and P. E. McKenney and J. Triplett and J. Walpole"
,title="The read-copy-update mechanism for supporting real-time applications on shared-memory multiprocessor systems with {Linux}"
,Year="2008"
,Month="April"
,journal="IBM Systems Journal"
,volume="47"
,number="2"
,pages="@@-@@"
,annotation="
RCU, realtime RCU, sleepable RCU, performance.
"
}

89
Documentation/RCU/checklist.txt
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@ -13,10 +13,13 @@ over a rather long period of time, but improvements are always welcome!
detailed performance measurements show that RCU is nonetheless
the right tool for the job.
The other exception would be where performance is not an issue,
and RCU provides a simpler implementation. An example of this
situation is the dynamic NMI code in the Linux 2.6 kernel,
at least on architectures where NMIs are rare.
Another exception is where performance is not an issue, and RCU
provides a simpler implementation. An example of this situation
is the dynamic NMI code in the Linux 2.6 kernel, at least on
architectures where NMIs are rare.
Yet another exception is where the low real-time latency of RCU's
read-side primitives is critically important.
1. Does the update code have proper mutual exclusion?
@ -39,9 +42,10 @@ over a rather long period of time, but improvements are always welcome!
2. Do the RCU read-side critical sections make proper use of
rcu_read_lock() and friends? These primitives are needed
to suppress preemption (or bottom halves, in the case of
rcu_read_lock_bh()) in the read-side critical sections,
and are also an excellent aid to readability.
to prevent grace periods from ending prematurely, which
could result in data being unceremoniously freed out from
under your read-side code, which can greatly increase the
actuarial risk of your kernel.
As a rough rule of thumb, any dereference of an RCU-protected
pointer must be covered by rcu_read_lock() or rcu_read_lock_bh()
@ -54,15 +58,30 @@ over a rather long period of time, but improvements are always welcome!
be running while updates are in progress. There are a number
of ways to handle this concurrency, depending on the situation:
a. Make updates appear atomic to readers. For example,
a. Use the RCU variants of the list and hlist update
primitives to add, remove, and replace elements on an
RCU-protected list. Alternatively, use the RCU-protected
trees that have been added to the Linux kernel.
This is almost always the best approach.
b. Proceed as in (a) above, but also maintain per-element
locks (that are acquired by both readers and writers)
that guard per-element state. Of course, fields that
the readers refrain from accessing can be guarded by the
update-side lock.
This works quite well, also.
c. Make updates appear atomic to readers. For example,
pointer updates to properly aligned fields will appear
atomic, as will individual atomic primitives. Operations
performed under a lock and sequences of multiple atomic
primitives will -not- appear to be atomic.
This is almost always the best approach.
This can work, but is starting to get a bit tricky.
b. Carefully order the updates and the reads so that
d. Carefully order the updates and the reads so that
readers see valid data at all phases of the update.
This is often more difficult than it sounds, especially
given modern CPUs' tendency to reorder memory references.
@ -123,18 +142,22 @@ over a rather long period of time, but improvements are always welcome!
when publicizing a pointer to a structure that can
be traversed by an RCU read-side critical section.
5. If call_rcu(), or a related primitive such as call_rcu_bh(),
is used, the callback function must be written to be called
from softirq context. In particular, it cannot block.
5. If call_rcu(), or a related primitive such as call_rcu_bh() or
call_rcu_sched(), is used, the callback function must be
written to be called from softirq context. In particular,
it cannot block.
6. Since synchronize_rcu() can block, it cannot be called from
any sort of irq context.
any sort of irq context. Ditto for synchronize_sched() and
synchronize_srcu().
7. If the updater uses call_rcu(), then the corresponding readers
must use rcu_read_lock() and rcu_read_unlock(). If the updater
uses call_rcu_bh(), then the corresponding readers must use
rcu_read_lock_bh() and rcu_read_unlock_bh(). Mixing things up
will result in confusion and broken kernels.
rcu_read_lock_bh() and rcu_read_unlock_bh(). If the updater
uses call_rcu_sched(), then the corresponding readers must
disable preemption. Mixing things up will result in confusion
and broken kernels.
One exception to this rule: rcu_read_lock() and rcu_read_unlock()
may be substituted for rcu_read_lock_bh() and rcu_read_unlock_bh()
@ -143,9 +166,9 @@ over a rather long period of time, but improvements are always welcome!
such cases is a must, of course! And the jury is still out on
whether the increased speed is worth it.
8. Although synchronize_rcu() is a bit slower than is call_rcu(),
it usually results in simpler code. So, unless update
performance is critically important or the updaters cannot block,
8. Although synchronize_rcu() is slower than is call_rcu(), it
usually results in simpler code. So, unless update performance
is critically important or the updaters cannot block,
synchronize_rcu() should be used in preference to call_rcu().
An especially important property of the synchronize_rcu()
@ -187,23 +210,23 @@ over a rather long period of time, but improvements are always welcome!
number of updates per grace period.
9. All RCU list-traversal primitives, which include
list_for_each_rcu(), list_for_each_entry_rcu(),
rcu_dereference(), list_for_each_rcu(), list_for_each_entry_rcu(),
list_for_each_continue_rcu(), and list_for_each_safe_rcu(),
must be within an RCU read-side critical section. RCU
must be either within an RCU read-side critical section or
must be protected by appropriate update-side locks. RCU
read-side critical sections are delimited by rcu_read_lock()
and rcu_read_unlock(), or by similar primitives such as
rcu_read_lock_bh() and rcu_read_unlock_bh().
Use of the _rcu() list-traversal primitives outside of an
RCU read-side critical section causes no harm other than
a slight performance degradation on Alpha CPUs. It can
also be quite helpful in reducing code bloat when common
code is shared between readers and updaters.
The reason that it is permissible to use RCU list-traversal
primitives when the update-side lock is held is that doing so
can be quite helpful in reducing code bloat when common code is
shared between readers and updaters.
10. Conversely, if you are in an RCU read-side critical section,
you -must- use the "_rcu()" variants of the list macros.
Failing to do so will break Alpha and confuse people reading
your code.
and you don't hold the appropriate update-side lock, you -must-
use the "_rcu()" variants of the list macros. Failing to do so
will break Alpha and confuse people reading your code.
11. Note that synchronize_rcu() -only- guarantees to wait until
all currently executing rcu_read_lock()-protected RCU read-side
@ -230,6 +253,14 @@ over a rather long period of time, but improvements are always welcome!
must use whatever locking or other synchronization is required
to safely access and/or modify that data structure.
RCU callbacks are -usually- executed on the same CPU that executed
the corresponding call_rcu(), call_rcu_bh(), or call_rcu_sched(),
but are by -no- means guaranteed to be. For example, if a given
CPU goes offline while having an RCU callback pending, then that
RCU callback will execute on some surviving CPU. (If this was
not the case, a self-spawning RCU callback would prevent the
victim CPU from ever going offline.)
14. SRCU (srcu_read_lock(), srcu_read_unlock(), and synchronize_srcu())
may only be invoked from process context. Unlike other forms of
RCU, it -is- permissible to block in an SRCU read-side critical

48
Documentation/RCU/torture.txt
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@ -10,23 +10,30 @@ status messages via printk(), which can be examined via the dmesg
command (perhaps grepping for "torture"). The test is started
when the module is loaded, and stops when the module is unloaded.
However, actually setting this config option to "y" results in the system
running the test immediately upon boot, and ending only when the system
is taken down. Normally, one will instead want to build the system
with CONFIG_RCU_TORTURE_TEST=m and to use modprobe and rmmod to control
the test, perhaps using a script similar to the one shown at the end of
this document. Note that you will need CONFIG_MODULE_UNLOAD in order
to be able to end the test.
CONFIG_RCU_TORTURE_TEST_RUNNABLE
It is also possible to specify CONFIG_RCU_TORTURE_TEST=y, which will
result in the tests being loaded into the base kernel. In this case,
the CONFIG_RCU_TORTURE_TEST_RUNNABLE config option is used to specify
whether the RCU torture tests are to be started immediately during
boot or whether the /proc/sys/kernel/rcutorture_runnable file is used
to enable them. This /proc file can be used to repeatedly pause and
restart the tests, regardless of the initial state specified by the
CONFIG_RCU_TORTURE_TEST_RUNNABLE config option.
You will normally -not- want to start the RCU torture tests during boot
(and thus the default is CONFIG_RCU_TORTURE_TEST_RUNNABLE=n), but doing
this can sometimes be useful in finding boot-time bugs.
MODULE PARAMETERS
This module has the following parameters:
nreaders This is the number of RCU reading threads supported.
The default is twice the number of CPUs. Why twice?
To properly exercise RCU implementations with preemptible
read-side critical sections.
irqreaders Says to invoke RCU readers from irq level. This is currently
done via timers. Defaults to "1" for variants of RCU that
permit this. (Or, more accurately, variants of RCU that do
-not- permit this know to ignore this variable.)
nfakewriters This is the number of RCU fake writer threads to run. Fake
writer threads repeatedly use the synchronous "wait for
@ -37,6 +44,16 @@ nfakewriters This is the number of RCU fake writer threads to run. Fake
to trigger special cases caused by multiple writers, such as
the synchronize_srcu() early return optimization.
nreaders This is the number of RCU reading threads supported.
The default is twice the number of CPUs. Why twice?
To properly exercise RCU implementations with preemptible
read-side critical sections.
shuffle_interval
The number of seconds to keep the test threads affinitied
to a particular subset of the CPUs, defaults to 3 seconds.
Used in conjunction with test_no_idle_hz.
stat_interval The number of seconds between output of torture
statistics (via printk()). Regardless of the interval,
statistics are printed when the module is unloaded.
@ -44,10 +61,11 @@ stat_interval The number of seconds between output of torture
be printed -only- when the module is unloaded, and this
is the default.
shuffle_interval
The number of seconds to keep the test threads affinitied
to a particular subset of the CPUs, defaults to 5 seconds.
Used in conjunction with test_no_idle_hz.
stutter The length of time to run the test before pausing for this
same period of time. Defaults to "stutter=5", so as
to run and pause for (roughly) five-second intervals.
Specifying "stutter=0" causes the test to run continuously
without pausing, which is the old default behavior.
test_no_idle_hz Whether or not to test the ability of RCU to operate in
a kernel that disables the scheduling-clock interrupt to

62
Documentation/RCU/whatisRCU.txt
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@ -1,3 +1,11 @@
Please note that the "What is RCU?" LWN series is an excellent place
to start learning about RCU:
1. What is RCU, Fundamentally? http://lwn.net/Articles/262464/
2. What is RCU? Part 2: Usage http://lwn.net/Articles/263130/
3. RCU part 3: the RCU API http://lwn.net/Articles/264090/
What is RCU?
RCU is a synchronization mechanism that was added to the Linux kernel
@ -772,26 +780,18 @@ Linux-kernel source code, but it helps to have a full list of the
APIs, since there does not appear to be a way to categorize them
in docbook. Here is the list, by category.
Markers for RCU read-side critical sections:
rcu_read_lock
rcu_read_unlock
rcu_read_lock_bh
rcu_read_unlock_bh
srcu_read_lock
srcu_read_unlock
RCU pointer/list traversal:
rcu_dereference
list_for_each_rcu (to be deprecated in favor of
list_for_each_entry_rcu)
list_for_each_entry_rcu
list_for_each_continue_rcu (to be deprecated in favor of new
list_for_each_entry_continue_rcu)
hlist_for_each_entry_rcu
RCU pointer update:
list_for_each_rcu (to be deprecated in favor of
list_for_each_entry_rcu)
list_for_each_continue_rcu (to be deprecated in favor of new
list_for_each_entry_continue_rcu)
RCU pointer/list update:
rcu_assign_pointer
list_add_rcu
@ -799,16 +799,36 @@ RCU pointer update:
list_del_rcu
list_replace_rcu
hlist_del_rcu
hlist_add_after_rcu
hlist_add_before_rcu
hlist_add_head_rcu
hlist_replace_rcu
list_splice_init_rcu()
RCU grace period:
RCU: Critical sections Grace period Barrier
rcu_read_lock synchronize_net rcu_barrier
rcu_read_unlock synchronize_rcu
call_rcu
bh: Critical sections Grace period Barrier
rcu_read_lock_bh call_rcu_bh rcu_barrier_bh
rcu_read_unlock_bh
sched: Critical sections Grace period Barrier
[preempt_disable] synchronize_sched rcu_barrier_sched
[and friends] call_rcu_sched
SRCU: Critical sections Grace period Barrier
srcu_read_lock synchronize_srcu N/A
srcu_read_unlock
synchronize_net
synchronize_sched
synchronize_rcu
synchronize_srcu
call_rcu
call_rcu_bh
See the comment headers in the source code (or the docbook generated
from them) for more information.

327
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@ -0,0 +1,327 @@
----------------------------------------------------------------------
1. INTRODUCTION
Modern filesystems feature checksumming of data and metadata to
protect against data corruption. However, the detection of the
corruption is done at read time which could potentially be months
after the data was written. At that point the original data that the
application tried to write is most likely lost.
The solution is to ensure that the disk is actually storing what the
application meant it to. Recent additions to both the SCSI family
protocols (SBC Data Integrity Field, SCC protection proposal) as well
as SATA/T13 (External Path Protection) try to remedy this by adding
support for appending integrity metadata to an I/O. The integrity
metadata (or protection information in SCSI terminology) includes a
checksum for each sector as well as an incrementing counter that
ensures the individual sectors are written in the right order. And
for some protection schemes also that the I/O is written to the right
place on disk.
Current storage controllers and devices implement various protective
measures, for instance checksumming and scrubbing. But these
technologies are working in their own isolated domains or at best
between adjacent nodes in the I/O path. The interesting thing about
DIF and the other integrity extensions is that the protection format
is well defined and every node in the I/O path can verify the
integrity of the I/O and reject it if corruption is detected. This
allows not only corruption prevention but also isolation of the point
of failure.
----------------------------------------------------------------------
2. THE DATA INTEGRITY EXTENSIONS
As written, the protocol extensions only protect the path between
controller and storage device. However, many controllers actually
allow the operating system to interact with the integrity metadata
(IMD). We have been working with several FC/SAS HBA vendors to enable
the protection information to be transferred to and from their
controllers.
The SCSI Data Integrity Field works by appending 8 bytes of protection
information to each sector. The data + integrity metadata is stored
in 520 byte sectors on disk. Data + IMD are interleaved when
transferred between the controller and target. The T13 proposal is
similar.
Because it is highly inconvenient for operating systems to deal with
520 (and 4104) byte sectors, we approached several HBA vendors and
encouraged them to allow separation of the data and integrity metadata
scatter-gather lists.
The controller will interleave the buffers on write and split them on
read. This means that the Linux can DMA the data buffers to and from
host memory without changes to the page cache.
Also, the 16-bit CRC checksum mandated by both the SCSI and SATA specs
is somewhat heavy to compute in software. Benchmarks found that
calculating this checksum had a significant impact on system
performance for a number of workloads. Some controllers allow a
lighter-weight checksum to be used when interfacing with the operating
system. Emulex, for instance, supports the TCP/IP checksum instead.
The IP checksum received from the OS is converted to the 16-bit CRC
when writing and vice versa. This allows the integrity metadata to be
generated by Linux or the application at very low cost (comparable to
software RAID5).
The IP checksum is weaker than the CRC in terms of detecting bit
errors. However, the strength is really in the separation of the data
buffers and the integrity metadata. These two distinct buffers much
match up for an I/O to complete.
The separation of the data and integrity metadata buffers as well as
the choice in checksums is referred to as the Data Integrity
Extensions. As these extensions are outside the scope of the protocol
bodies (T10, T13), Oracle and its partners are trying to standardize
them within the Storage Networking Industry Association.
----------------------------------------------------------------------
3. KERNEL CHANGES
The data integrity framework in Linux enables protection information
to be pinned to I/Os and sent to/received from controllers that
support it.
The advantage to the integrity extensions in SCSI and SATA is that
they enable us to protect the entire path from application to storage
device. However, at the same time this is also the biggest
disadvantage. It means that the protection information must be in a
format that can be understood by the disk.
Generally Linux/POSIX applications are agnostic to the intricacies of
the storage devices they are accessing. The virtual filesystem switch
and the block layer make things like hardware sector size and
transport protocols completely transparent to the application.
However, this level of detail is required when preparing the
protection information to send to a disk. Consequently, the very
concept of an end-to-end protection scheme is a layering violation.
It is completely unreasonable for an application to be aware whether
it is accessing a SCSI or SATA disk.
The data integrity support implemented in Linux attempts to hide this
from the application. As far as the application (and to some extent
the kernel) is concerned, the integrity metadata is opaque information
that's attached to the I/O.
The current implementation allows the block layer to automatically
generate the protection information for any I/O. Eventually the
intent is to move the integrity metadata calculation to userspace for
user data. Metadata and other I/O that originates within the kernel
will still use the automatic generation interface.
Some storage devices allow each hardware sector to be tagged with a
16-bit value. The owner of this tag space is the owner of the block
device. I.e. the filesystem in most cases. The filesystem can use
this extra space to tag sectors as they see fit. Because the tag
space is limited, the block interface allows tagging bigger chunks by
way of interleaving. This way, 8*16 bits of information can be
attached to a typical 4KB filesystem block.
This also means that applications such as fsck and mkfs will need
access to manipulate the tags from user space. A passthrough
interface for this is being worked on.
----------------------------------------------------------------------
4. BLOCK LAYER IMPLEMENTATION DETAILS
4.1 BIO
The data integrity patches add a new field to struct bio when
CONFIG_BLK_DEV_INTEGRITY is enabled. bio->bi_integrity is a pointer
to a struct bip which contains the bio integrity payload. Essentially
a bip is a trimmed down struct bio which holds a bio_vec containing
the integrity metadata and the required housekeeping information (bvec
pool, vector count, etc.)
A kernel subsystem can enable data integrity protection on a bio by
calling bio_integrity_alloc(bio). This will allocate and attach the
bip to the bio.
Individual pages containing integrity metadata can subsequently be
attached using bio_integrity_add_page().
bio_free() will automatically free the bip.
4.2 BLOCK DEVICE
Because the format of the protection data is tied to the physical
disk, each block device has been extended with a block integrity
profile (struct blk_integrity). This optional profile is registered
with the block layer using blk_integrity_register().
The profile contains callback functions for generating and verifying
the protection data, as well as getting and setting application tags.
The profile also contains a few constants to aid in completing,
merging and splitting the integrity metadata.
Layered block devices will need to pick a profile that's appropriate
for all subdevices. blk_integrity_compare() can help with that. DM
and MD linear, RAID0 and RAID1 are currently supported. RAID4/5/6
will require extra work due to the application tag.
----------------------------------------------------------------------
5.0 BLOCK LAYER INTEGRITY API
5.1 NORMAL FILESYSTEM
The normal filesystem is unaware that the underlying block device
is capable of sending/receiving integrity metadata. The IMD will
be automatically generated by the block layer at submit_bio() time
in case of a WRITE. A READ request will cause the I/O integrity
to be verified upon completion.
IMD generation and verification can be toggled using the
/sys/block/<bdev>/integrity/write_generate
and
/sys/block/<bdev>/integrity/read_verify
flags.
5.2 INTEGRITY-AWARE FILESYSTEM
A filesystem that is integrity-aware can prepare I/Os with IMD
attached. It can also use the application tag space if this is
supported by the block device.
int bdev_integrity_enabled(block_device, int rw);
bdev_integrity_enabled() will return 1 if the block device
supports integrity metadata transfer for the data direction
specified in 'rw'.
bdev_integrity_enabled() honors the write_generate and
read_verify flags in sysfs and will respond accordingly.
int bio_integrity_prep(bio);
To generate IMD for WRITE and to set up buffers for READ, the
filesystem must call bio_integrity_prep(bio).
Prior to calling this function, the bio data direction and start
sector must be set, and the bio should have all data pages
added. It is up to the caller to ensure that the bio does not
change while I/O is in progress.
bio_integrity_prep() should only be called if
bio_integrity_enabled() returned 1.
int bio_integrity_tag_size(bio);
If the filesystem wants to use the application tag space it will
first have to find out how much storage space is available.
Because tag space is generally limited (usually 2 bytes per
sector regardless of sector size), the integrity framework
supports interleaving the information between the sectors in an
I/O.
Filesystems can call bio_integrity_tag_size(bio) to find out how
many bytes of storage are available for that particular bio.
Another option is bdev_get_tag_size(block_device) which will
return the number of available bytes per hardware sector.
int bio_integrity_set_tag(bio, void *tag_buf, len);
After a successful return from bio_integrity_prep(),
bio_integrity_set_tag() can be used to attach an opaque tag
buffer to a bio. Obviously this only makes sense if the I/O is
a WRITE.
int bio_integrity_get_tag(bio, void *tag_buf, len);
Similarly, at READ I/O completion time the filesystem can
retrieve the tag buffer using bio_integrity_get_tag().
6.3 PASSING EXISTING INTEGRITY METADATA
Filesystems that either generate their own integrity metadata or
are capable of transferring IMD from user space can use the
following calls:
struct bip * bio_integrity_alloc(bio, gfp_mask, nr_pages);
Allocates the bio integrity payload and hangs it off of the bio.
nr_pages indicate how many pages of protection data need to be
stored in the integrity bio_vec list (similar to bio_alloc()).
The integrity payload will be freed at bio_free() time.
int bio_integrity_add_page(bio, page, len, offset);
Attaches a page containing integrity metadata to an existing
bio. The bio must have an existing bip,
i.e. bio_integrity_alloc() must have been called. For a WRITE,
the integrity metadata in the pages must be in a format
understood by the target device with the notable exception that
the sector numbers will be remapped as the request traverses the
I/O stack. This implies that the pages added using this call
will be modified during I/O! The first reference tag in the
integrity metadata must have a value of bip->bip_sector.
Pages can be added using bio_integrity_add_page() as long as
there is room in the bip bio_vec array (nr_pages).
Upon completion of a READ operation, the attached pages will
contain the integrity metadata received from the storage device.
It is up to the receiver to process them and verify data
integrity upon completion.
6.4 REGISTERING A BLOCK DEVICE AS CAPABLE OF EXCHANGING INTEGRITY
METADATA
To enable integrity exchange on a block device the gendisk must be
registered as capable:
int blk_integrity_register(gendisk, blk_integrity);
The blk_integrity struct is a template and should contain the
following:
static struct blk_integrity my_profile = {
.name = "STANDARDSBODY-TYPE-VARIANT-CSUM",
.generate_fn = my_generate_fn,
.verify_fn = my_verify_fn,
.get_tag_fn = my_get_tag_fn,
.set_tag_fn = my_set_tag_fn,
.tuple_size = sizeof(struct my_tuple_size),
.tag_size = <tag bytes per hw sector>,
};
'name' is a text string which will be visible in sysfs. This is
part of the userland API so chose it carefully and never change
it. The format is standards body-type-variant.
E.g. T10-DIF-TYPE1-IP or T13-EPP-0-CRC.
'generate_fn' generates appropriate integrity metadata (for WRITE).
'verify_fn' verifies that the data buffer matches the integrity
metadata.
'tuple_size' must be set to match the size of the integrity
metadata per sector. I.e. 8 for DIF and EPP.
'tag_size' must be set to identify how many bytes of tag space
are available per hardware sector. For DIF this is either 2 or
0 depending on the value of the Control Mode Page ATO bit.
See 6.2 for a description of get_tag_fn and set_tag_fn.
----------------------------------------------------------------------
2007-12-24 Martin K. Petersen <martin.petersen@oracle.com>

26
Documentation/cputopology.txt
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@ -14,9 +14,8 @@ represent the thread siblings to cpu X in the same physical package;
To implement it in an architecture-neutral way, a new source file,
drivers/base/topology.c, is to export the 4 attributes.
If one architecture wants to support this feature, it just needs to
implement 4 defines, typically in file include/asm-XXX/topology.h.
The 4 defines are:
For an architecture to support this feature, it must define some of
these macros in include/asm-XXX/topology.h:
#define topology_physical_package_id(cpu)
#define topology_core_id(cpu)
#define topology_thread_siblings(cpu)
@ -25,17 +24,10 @@ The 4 defines are:
The type of **_id is int.
The type of siblings is cpumask_t.
To be consistent on all architectures, the 4 attributes should have
default values if their values are unavailable. Below is the rule.
1) physical_package_id: If cpu has no physical package id, -1 is the
default value.
2) core_id: If cpu doesn't support multi-core, its core id is 0.
3) thread_siblings: Just include itself, if the cpu doesn't support
HT/multi-thread.
4) core_siblings: Just include itself, if the cpu doesn't support
multi-core and HT/Multi-thread.
So be careful when declaring the 4 defines in include/asm-XXX/topology.h.
If an attribute isn't defined on an architecture, it won't be exported.
To be consistent on all architectures, include/linux/topology.h
provides default definitions for any of the above macros that are
not defined by include/asm-XXX/topology.h:
1) physical_package_id: -1
2) core_id: 0
3) thread_siblings: just the given CPU
4) core_siblings: just the given CPU

39
Documentation/feature-removal-schedule.txt
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@ -222,13 +222,6 @@ Who: Thomas Gleixner <tglx@linutronix.de>
---------------------------
What: i2c-i810, i2c-prosavage and i2c-savage4
When: May 2008
Why: These drivers are superseded by i810fb, intelfb and savagefb.
Who: Jean Delvare <khali@linux-fr.org>
---------------------------
What (Why):
- include/linux/netfilter_ipv4/ipt_TOS.h ipt_tos.h header files
(superseded by xt_TOS/xt_tos target & match)
@ -315,9 +308,41 @@ Who: Matthew Wilcox <willy@linux.intel.com>
---------------------------
What: SCTP_GET_PEER_ADDRS_NUM_OLD, SCTP_GET_PEER_ADDRS_OLD,
SCTP_GET_LOCAL_ADDRS_NUM_OLD, SCTP_GET_LOCAL_ADDRS_OLD
When: June 2009
Why: A newer version of the options have been introduced in 2005 that
removes the limitions of the old API. The sctp library has been
converted to use these new options at the same time. Any user
space app that directly uses the old options should convert to using
the new options.
Who: Vlad Yasevich <vladislav.yasevich@hp.com>
---------------------------
What: CONFIG_THERMAL_HWMON
When: January 2009
Why: This option was introduced just to allow older lm-sensors userspace
to keep working over the upgrade to 2.6.26. At the scheduled time of
removal fixed lm-sensors (2.x or 3.x) should be readily available.
Who: Rene Herman <rene.herman@gmail.com>
---------------------------
What: Code that is now under CONFIG_WIRELESS_EXT_SYSFS
(in net/core/net-sysfs.c)
When: After the only user (hal) has seen a release with the patches
for enough time, probably some time in 2010.
Why: Over 1K .text/.data size reduction, data is available in other
ways (ioctls)
Who: Johannes Berg <johannes@sipsolutions.net>
---------------------------
What: CONFIG_NF_CT_ACCT
When: 2.6.29
Why: Accounting can now be enabled/disabled without kernel recompilation.
Currently used only to set a default value for a feature that is also
controlled by a kernel/module/sysfs/sysctl parameter.
Who: Krzysztof Piotr Oledzki <ole@ans.pl>

10
Documentation/filesystems/bfs.txt
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@ -26,11 +26,11 @@ You can simplify mounting by just typing:
this will allocate the first available loopback device (and load loop.o
kernel module if necessary) automatically. If the loopback driver is not
loaded automatically, make sure that your kernel is compiled with kmod
support (CONFIG_KMOD) enabled. Beware that umount will not
deallocate /dev/loopN device if /etc/mtab file on your system is a
symbolic link to /proc/mounts. You will need to do it manually using
"-d" switch of losetup(8). Read losetup(8) manpage for more info.
loaded automatically, make sure that you have compiled the module and
that modprobe is functioning. Beware that umount will not deallocate
/dev/loopN device if /etc/mtab file on your system is a symbolic link to
/proc/mounts. You will need to do it manually using "-d" switch of
losetup(8). Read losetup(8) manpage for more info.
To create the BFS image under UnixWare you need to find out first which
slice contains it. The command prtvtoc(1M) is your friend:

4
Documentation/filesystems/configfs/configfs_example.c
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@ -279,7 +279,7 @@ static struct config_item *simple_children_make_item(struct config_group *group,
simple_child = kzalloc(sizeof(struct simple_child), GFP_KERNEL);
if (!simple_child)
return NULL;
return ERR_PTR(-ENOMEM);
config_item_init_type_name(&simple_child->item, name,
@ -366,7 +366,7 @@ static struct config_group *group_children_make_group(struct config_group *group
simple_children = kzalloc(sizeof(struct simple_children),
GFP_KERNEL);
if (!simple_children)
return NULL;
return ERR_PTR(-ENOMEM);
config_group_init_type_name(&simple_children->group, name,

125
Documentation/filesystems/ext4.txt
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@ -13,72 +13,93 @@ Mailing list: linux-ext4@vger.kernel.org
1. Quick usage instructions:
===========================
- Grab updated e2fsprogs from
ftp://ftp.kernel.org/pub/linux/kernel/people/tytso/e2fsprogs-interim/
This is a patchset on top of e2fsprogs-1.39, which can be found at
- Compile and install the latest version of e2fsprogs (as of this
writing version 1.41) from:
http://sourceforge.net/project/showfiles.php?group_id=2406
or
ftp://ftp.kernel.org/pub/linux/kernel/people/tytso/e2fsprogs/
- It's still mke2fs -j /dev/hda1
or grab the latest git repository from:
- mount /dev/hda1 /wherever -t ext4dev
git://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git
- To enable extents,
- Create a new filesystem using the ext4dev filesystem type:
mount /dev/hda1 /wherever -t ext4dev -o extents
# mke2fs -t ext4dev /dev/hda1
- The filesystem is compatible with the ext3 driver until you add a file
which has extents (ie: `mount -o extents', then create a file).
Or configure an existing ext3 filesystem to support extents and set
the test_fs flag to indicate that it's ok for an in-development
filesystem to touch this filesystem:
NOTE: The "extents" mount flag is temporary. It will soon go away and
extents will be enabled by the "-o extents" flag to mke2fs or tune2fs
# tune2fs -O extents -E test_fs /dev/hda1
If the filesystem was created with 128 byte inodes, it can be
converted to use 256 byte for greater efficiency via:
# tune2fs -I 256 /dev/hda1
(Note: we currently do not have tools to convert an ext4dev
filesystem back to ext3; so please do not do try this on production
filesystems.)
- Mounting:
# mount -t ext4dev /dev/hda1 /wherever
- When comparing performance with other filesystems, remember that
ext3/4 by default offers higher data integrity guarantees than most. So
when comparing with a metadata-only journalling filesystem, use `mount -o
data=writeback'. And you might as well use `mount -o nobh' too along
with it. Making the journal larger than the mke2fs default often helps
performance with metadata-intensive workloads.
ext3/4 by default offers higher data integrity guarantees than most.
So when comparing with a metadata-only journalling filesystem, such
as ext3, use `mount -o data=writeback'. And you might as well use
`mount -o nobh' too along with it. Making the journal larger than
the mke2fs default often helps performance with metadata-intensive
workloads.
2. Features
===========
2.1 Currently available
* ability to use filesystems > 16TB
* ability to use filesystems > 16TB (e2fsprogs support not available yet)
* extent format reduces metadata overhead (RAM, IO for access, transactions)
* extent format more robust in face of on-disk corruption due to magics,
* internal redunancy in tree
2.1 Previously available, soon to be enabled by default by "mkefs.ext4":
* dir_index and resize inode will be on by default
* large inodes will be used by default for fast EAs, nsec timestamps, etc
* improved file allocation (multi-block alloc)
* fix 32000 subdirectory limit
* nsec timestamps for mtime, atime, ctime, create time
* inode version field on disk (NFSv4, Lustre)
* reduced e2fsck time via uninit_bg feature
* journal checksumming for robustness, performance
* persistent file preallocation (e.g for streaming media, databases)
* ability to pack bitmaps and inode tables into larger virtual groups via the
flex_bg feature
* large file support
* Inode allocation using large virtual block groups via flex_bg
* delayed allocation
* large block (up to pagesize) support
* efficent new ordered mode in JBD2 and ext4(avoid using buffer head to force
the ordering)
2.2 Candidate features for future inclusion
There are several under discussion, whether they all make it in is
partly a function of how much time everyone has to work on them:
* Online defrag (patches available but not well tested)
* reduced mke2fs time via lazy itable initialization in conjuction with
the uninit_bg feature (capability to do this is available in e2fsprogs
but a kernel thread to do lazy zeroing of unused inode table blocks
after filesystem is first mounted is required for safety)
* improved file allocation (multi-block alloc, delayed alloc; basically done)
* fix 32000 subdirectory limit (patch exists, needs some e2fsck work)
* nsec timestamps for mtime, atime, ctime, create time (patch exists,
needs some e2fsck work)
* inode version field on disk (NFSv4, Lustre; prototype exists)
* reduced mke2fs/e2fsck time via uninitialized groups (prototype exists)
* journal checksumming for robustness, performance (prototype exists)
* persistent file preallocation (e.g for streaming media, databases)
There are several others under discussion, whether they all make it in is
partly a function of how much time everyone has to work on them. Features like
metadata checksumming have been discussed and planned for a bit but no patches
exist yet so I'm not sure they're in the near-term roadmap.
Features like metadata checksumming have been discussed and planned for
a bit but no patches exist yet so I'm not sure they're in the near-term
roadmap.
The big performance win will come with mballoc, delalloc and flex_bg
grouping of bitmaps and inode tables. Some test results available here:
The big performance win will come with mballoc and delalloc. CFS has
been using mballoc for a few years already with Lustre, and IBM + Bull
did a lot of benchmarking on it. The reason it isn't in the first set of
patches is partly a manageability issue, and partly because it doesn't
directly affect the on-disk format (outside of much better allocation)
so it isn't critical to get into the first round of changes. I believe
Alex is working on a new set of patches right now.
- http://www.bullopensource.org/ext4/20080530/ffsb-write-2.6.26-rc2.html
- http://www.bullopensource.org/ext4/20080530/ffsb-readwrite-2.6.26-rc2.html
3. Options
==========
@ -222,9 +243,11 @@ stripe=n Number of filesystem blocks that mballoc will try
to use for allocation size and alignment. For RAID5/6
systems this should be the number of data
disks * RAID chunk size in file system blocks.
delalloc (*) Deferring block allocation until write-out time.
nodelalloc Disable delayed allocation. Blocks are allocation
when data is copied from user to page cache.
Data Mode
---------
=========
There are 3 different data modes:
* writeback mode
@ -236,10 +259,10 @@ typically provide the best ext4 performance.
* ordered mode
In data=ordered mode, ext4 only officially journals metadata, but it logically
groups metadata and data blocks into a single unit called a transaction. When
it's time to write the new metadata out to disk, the associated data blocks
are written first. In general, this mode performs slightly slower than
writeback but significantly faster than journal mode.
groups metadata information related to data changes with the data blocks into a
single unit called a transaction. When it's time to write the new metadata
out to disk, the associated data blocks are written first. In general,
this mode performs slightly slower than writeback but significantly faster than journal mode.
* journal mode
data=journal mode provides full data and metadata journaling. All new data is
@ -247,7 +270,8 @@ written to the journal first, and then to its final location.
In the event of a crash, the journal can be replayed, bringing both data and
metadata into a consistent state. This mode is the slowest except when data
needs to be read from and written to disk at the same time where it
outperforms all others modes.
outperforms all others modes. Curently ext4 does not have delayed
allocation support if this data journalling mode is selected.
References
==========
@ -256,7 +280,8 @@ kernel source: <file:fs/ext4/>
<file:fs/jbd2/>
programs: http://e2fsprogs.sourceforge.net/
http://ext2resize.sourceforge.net
useful links: http://fedoraproject.org/wiki/ext3-devel
http://www.bullopensource.org/ext4/
http://ext4.wiki.kernel.org/index.php/Main_Page
http://fedoraproject.org/wiki/Features/Ext4

114
Documentation/filesystems/gfs2-glocks.txt Normal file
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@ -0,0 +1,114 @@
Glock internal locking rules
------------------------------
This documents the basic principles of the glock state machine
internals. Each glock (struct gfs2_glock in fs/gfs2/incore.h)
has two main (internal) locks:
1. A spinlock (gl_spin) which protects the internal state such
as gl_state, gl_target and the list of holders (gl_holders)
2. A non-blocking bit lock, GLF_LOCK, which is used to prevent other
threads from making calls to the DLM, etc. at the same time. If a
thread takes this lock, it must then call run_queue (usually via the
workqueue) when it releases it in order to ensure any pending tasks
are completed.
The gl_holders list contains all the queued lock requests (not
just the holders) associated with the glock. If there are any
held locks, then they will be contiguous entries at the head
of the list. Locks are granted in strictly the order that they
are queued, except for those marked LM_FLAG_PRIORITY which are
used only during recovery, and even then only for journal locks.
There are three lock states that users of the glock layer can request,
namely shared (SH), deferred (DF) and exclusive (EX). Those translate
to the following DLM lock modes:
Glock mode | DLM lock mode
------------------------------
UN | IV/NL Unlocked (no DLM lock associated with glock) or NL
SH | PR (Protected read)
DF | CW (Concurrent write)
EX | EX (Exclusive)
Thus DF is basically a shared mode which is incompatible with the "normal"
shared lock mode, SH. In GFS2 the DF mode is used exclusively for direct I/O
operations. The glocks are basically a lock plus some routines which deal
with cache management. The following rules apply for the cache:
Glock mode | Cache data | Cache Metadata | Dirty Data | Dirty Metadata
--------------------------------------------------------------------------
UN | No | No | No | No
SH | Yes | Yes | No | No
DF | No | Yes | No | No
EX | Yes | Yes | Yes | Yes
These rules are implemented using the various glock operations which
are defined for each type of glock. Not all types of glocks use
all the modes. Only inode glocks use the DF mode for example.
Table of glock operations and per type constants:
Field | Purpose
----------------------------------------------------------------------------
go_xmote_th | Called before remote state change (e.g. to sync dirty data)
go_xmote_bh | Called after remote state change (e.g. to refill cache)
go_inval | Called if remote state change requires invalidating the cache
go_demote_ok | Returns boolean value of whether its ok to demote a glock
| (e.g. checks timeout, and that there is no cached data)
go_lock | Called for the first local holder of a lock
go_unlock | Called on the final local unlock of a lock
go_dump | Called to print content of object for debugfs file, or on
| error to dump glock to the log.
go_type; | The type of the glock, LM_TYPE_.....
go_min_hold_time | The minimum hold time
The minimum hold time for each lock is the time after a remote lock
grant for which we ignore remote demote requests. This is in order to
prevent a situation where locks are being bounced around the cluster
from node to node with none of the nodes making any progress. This
tends to show up most with shared mmaped files which are being written
to by multiple nodes. By delaying the demotion in response to a
remote callback, that gives the userspace program time to make
some progress before the pages are unmapped.
There is a plan to try and remove the go_lock and go_unlock callbacks
if possible, in order to try and speed up the fast path though the locking.
Also, eventually we hope to make the glock "EX" mode locally shared
such that any local locking will be done with the i_mutex as required
rather than via the glock.
Locking rules for glock operations:
Operation | GLF_LOCK bit lock held | gl_spin spinlock held
-----------------------------------------------------------------
go_xmote_th | Yes | No
go_xmote_bh | Yes | No
go_inval | Yes | No
go_demote_ok | Sometimes | Yes
go_lock | Yes | No
go_unlock | Yes | No
go_dump | Sometimes | Yes
N.B. Operations must not drop either the bit lock or the spinlock
if its held on entry. go_dump and do_demote_ok must never block.
Note that go_dump will only be called if the glock's state
indicates that it is caching uptodate data.
Glock locking order within GFS2:
1. i_mutex (if required)
2. Rename glock (for rename only)
3. Inode glock(s)
(Parents before children, inodes at "same level" with same parent in
lock number order)
4. Rgrp glock(s) (for (de)allocation operations)
5. Transaction glock (via gfs2_trans_begin) for non-read operations
6. Page lock (always last, very important!)
There are two glocks per inode. One deals with access to the inode
itself (locking order as above), and the other, known as the iopen
glock is used in conjunction with the i_nlink field in the inode to
determine the lifetime of the inode in question. Locking of inodes
is on a per-inode basis. Locking of rgrps is on a per rgrp basis.

103
Documentation/filesystems/nfs-rdma.txt
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@ -5,7 +5,7 @@
################################################################################
Author: NetApp and Open Grid Computing
Date: April 15, 2008
Date: May 29, 2008
Table of Contents
~~~~~~~~~~~~~~~~~
@ -60,16 +60,18 @@ Installation
The procedures described in this document have been tested with
distributions from Red Hat's Fedora Project (http://fedora.redhat.com/).
- Install nfs-utils-1.1.1 or greater on the client
- Install nfs-utils-1.1.2 or greater on the client
An NFS/RDMA mount point can only be obtained by using the mount.nfs
command in nfs-utils-1.1.1 or greater. To see which version of mount.nfs
you are using, type:
An NFS/RDMA mount point can be obtained by using the mount.nfs command in
nfs-utils-1.1.2 or greater (nfs-utils-1.1.1 was the first nfs-utils
version with support for NFS/RDMA mounts, but for various reasons we
recommend using nfs-utils-1.1.2 or greater). To see which version of
mount.nfs you are using, type:
> /sbin/mount.nfs -V
$ /sbin/mount.nfs -V
If the version is less than 1.1.1 or the command does not exist,
then you will need to install the latest version of nfs-utils.
If the version is less than 1.1.2 or the command does not exist,
you should install the latest version of nfs-utils.
Download the latest package from:
@ -77,22 +79,33 @@ Installation
Uncompress the package and follow the installation instructions.
If you will not be using GSS and NFSv4, the installation process
can be simplified by disabling these features when running configure:
If you will not need the idmapper and gssd executables (you do not need
these to create an NFS/RDMA enabled mount command), the installation
process can be simplified by disabling these features when running
configure:
> ./configure --disable-gss --disable-nfsv4
$ ./configure --disable-gss --disable-nfsv4
For more information on this see the package's README and INSTALL files.
To build nfs-utils you will need the tcp_wrappers package installed. For
more information on this see the package's README and INSTALL files.
After building the nfs-utils package, there will be a mount.nfs binary in
the utils/mount directory. This binary can be used to initiate NFS v2, v3,
or v4 mounts. To initiate a v4 mount, the binary must be called mount.nfs4.
The standard technique is to create a symlink called mount.nfs4 to mount.nfs.
or v4 mounts. To initiate a v4 mount, the binary must be called
mount.nfs4. The standard technique is to create a symlink called
mount.nfs4 to mount.nfs.
NOTE: mount.nfs and therefore nfs-utils-1.1.1 or greater is only needed
This mount.nfs binary should be installed at /sbin/mount.nfs as follows:
$ sudo cp utils/mount/mount.nfs /sbin/mount.nfs
In this location, mount.nfs will be invoked automatically for NFS mounts
by the system mount commmand.
NOTE: mount.nfs and therefore nfs-utils-1.1.2 or greater is only needed
on the NFS client machine. You do not need this specific version of
nfs-utils on the server. Furthermore, only the mount.nfs command from
nfs-utils-1.1.1 is needed on the client.
nfs-utils-1.1.2 is needed on the client.
- Install a Linux kernel with NFS/RDMA
@ -156,8 +169,8 @@ Check RDMA and NFS Setup
this time. For example, if you are using a Mellanox Tavor/Sinai/Arbel
card:
> modprobe ib_mthca
> modprobe ib_ipoib
$ modprobe ib_mthca
$ modprobe ib_ipoib
If you are using InfiniBand, make sure there is a Subnet Manager (SM)
running on the network. If your IB switch has an embedded SM, you can
@ -166,7 +179,7 @@ Check RDMA and NFS Setup
If an SM is running on your network, you should see the following:
> cat /sys/class/infiniband/driverX/ports/1/state
$ cat /sys/class/infiniband/driverX/ports/1/state
4: ACTIVE
where driverX is mthca0, ipath5, ehca3, etc.
@ -174,10 +187,10 @@ Check RDMA and NFS Setup
To further test the InfiniBand software stack, use IPoIB (this
assumes you have two IB hosts named host1 and host2):
host1> ifconfig ib0 a.b.c.x
host2> ifconfig ib0 a.b.c.y
host1> ping a.b.c.y
host2> ping a.b.c.x
host1$ ifconfig ib0 a.b.c.x
host2$ ifconfig ib0 a.b.c.y
host1$ ping a.b.c.y
host2$ ping a.b.c.x
For other device types, follow the appropriate procedures.
@ -202,11 +215,11 @@ NFS/RDMA Setup
/vol0 192.168.0.47(fsid=0,rw,async,insecure,no_root_squash)
/vol0 192.168.0.0/255.255.255.0(fsid=0,rw,async,insecure,no_root_squash)
The IP address(es) is(are) the client's IPoIB address for an InfiniBand HCA or the
cleint's iWARP address(es) for an RNIC.
The IP address(es) is(are) the client's IPoIB address for an InfiniBand
HCA or the cleint's iWARP address(es) for an RNIC.
NOTE: The "insecure" option must be used because the NFS/RDMA client does not
use a reserved port.
NOTE: The "insecure" option must be used because the NFS/RDMA client does
not use a reserved port.
Each time a machine boots:
@ -214,43 +227,45 @@ NFS/RDMA Setup
For InfiniBand using a Mellanox adapter:
> modprobe ib_mthca
> modprobe ib_ipoib
> ifconfig ib0 a.b.c.d
$ modprobe ib_mthca
$ modprobe ib_ipoib
$ ifconfig ib0 a.b.c.d
NOTE: use unique addresses for the client and server
- Start the NFS server
If the NFS/RDMA server was built as a module (CONFIG_SUNRPC_XPRT_RDMA=m in kernel config),
load the RDMA transport module:
If the NFS/RDMA server was built as a module (CONFIG_SUNRPC_XPRT_RDMA=m in
kernel config), load the RDMA transport module:
> modprobe svcrdma
$ modprobe svcrdma
Regardless of how the server was built (module or built-in), start the server:
Regardless of how the server was built (module or built-in), start the
server:
> /etc/init.d/nfs start
$ /etc/init.d/nfs start
or
> service nfs start
$ service nfs start
Instruct the server to listen on the RDMA transport:
> echo rdma 2050 > /proc/fs/nfsd/portlist
$ echo rdma 2050 > /proc/fs/nfsd/portlist
- On the client system
If the NFS/RDMA client was built as a module (CONFIG_SUNRPC_XPRT_RDMA=m in kernel config),
load the RDMA client module:
If the NFS/RDMA client was built as a module (CONFIG_SUNRPC_XPRT_RDMA=m in
kernel config), load the RDMA client module:
> modprobe xprtrdma.ko
$ modprobe xprtrdma.ko
Regardless of how the client was built (module or built-in), issue the mount.nfs command:
Regardless of how the client was built (module or built-in), use this
command to mount the NFS/RDMA server:
> /path/to/your/mount.nfs <IPoIB-server-name-or-address>:/<export> /mnt -i -o rdma,port=2050
$ mount -o rdma,port=2050 <IPoIB-server-name-or-address>:/<export> /mnt
To verify that the mount is using RDMA, run "cat /proc/mounts" and check the
"proto" field for the given mount.
To verify that the mount is using RDMA, run "cat /proc/mounts" and check
the "proto" field for the given mount.
Congratulations! You're using NFS/RDMA!

29
Documentation/filesystems/proc.txt
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@ -380,28 +380,35 @@ i386 and x86_64 platforms support the new IRQ vector displays.
Of some interest is the introduction of the /proc/irq directory to 2.4.
It could be used to set IRQ to CPU affinity, this means that you can "hook" an
IRQ to only one CPU, or to exclude a CPU of handling IRQs. The contents of the
irq subdir is one subdir for each IRQ, and one file; prof_cpu_mask
irq subdir is one subdir for each IRQ, and two files; default_smp_affinity and
prof_cpu_mask.
For example
> ls /proc/irq/
0 10 12 14 16 18 2 4 6 8 prof_cpu_mask
1 11 13 15 17 19 3 5 7 9
1 11 13 15 17 19 3 5 7 9 default_smp_affinity
> ls /proc/irq/0/
smp_affinity
The contents of the prof_cpu_mask file and each smp_affinity file for each IRQ
is the same by default:
smp_affinity is a bitmask, in which you can specify which CPUs can handle the
IRQ, you can set it by doing:
> cat /proc/irq/0/smp_affinity
> echo 1 > /proc/irq/10/smp_affinity
This means that only the first CPU will handle the IRQ, but you can also echo
5 which means that only the first and fourth CPU can handle the IRQ.
The contents of each smp_affinity file is the same by default:
> cat /proc/irq/0/smp_affinity
ffffffff
It's a bitmask, in which you can specify which CPUs can handle the IRQ, you can
set it by doing:
The default_smp_affinity mask applies to all non-active IRQs, which are the
IRQs which have not yet been allocated/activated, and hence which lack a
/proc/irq/[0-9]* directory.
> echo 1 > /proc/irq/prof_cpu_mask
This means that only the first CPU will handle the IRQ, but you can also echo 5
which means that only the first and fourth CPU can handle the IRQ.
prof_cpu_mask specifies which CPUs are to be profiled by the system wide
profiler. Default value is ffffffff (all cpus).
The way IRQs are routed is handled by the IO-APIC, and it's Round Robin
between all the CPUs which are allowed to handle it. As usual the kernel has

6
Documentation/filesystems/sysfs.txt
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@ -248,6 +248,7 @@ The top level sysfs directory looks like:
block/
bus/
class/
dev/
devices/
firmware/
net/
@ -274,6 +275,11 @@ fs/ contains a directory for some filesystems. Currently each
filesystem wanting to export attributes must create its own hierarchy
below fs/ (see ./fuse.txt for an example).
dev/ contains two directories char/ and block/. Inside these two
directories there are symlinks named <major>:<minor>. These symlinks
point to the sysfs directory for the given device. /sys/dev provides a
quick way to lookup the sysfs interface for a device from the result of
a stat(2) operation.
More information can driver-model specific features can be found in
Documentation/driver-model/.

164
Documentation/filesystems/ubifs.txt Normal file
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@ -0,0 +1,164 @@
Introduction
=============
UBIFS file-system stands for UBI File System. UBI stands for "Unsorted
Block Images". UBIFS is a flash file system, which means it is designed
to work with flash devices. It is important to understand, that UBIFS
is completely different to any traditional file-system in Linux, like
Ext2, XFS, JFS, etc. UBIFS represents a separate class of file-systems
which work with MTD devices, not block devices. The other Linux
file-system of this class is JFFS2.
To make it more clear, here is a small comparison of MTD devices and
block devices.
1 MTD devices represent flash devices and they consist of eraseblocks of
rather large size, typically about 128KiB. Block devices consist of
small blocks, typically 512 bytes.
2 MTD devices support 3 main operations - read from some offset within an
eraseblock, write to some offset within an eraseblock, and erase a whole
eraseblock. Block devices support 2 main operations - read a whole
block and write a whole block.
3 The whole eraseblock has to be erased before it becomes possible to
re-write its contents. Blocks may be just re-written.
4 Eraseblocks become worn out after some number of erase cycles -
typically 100K-1G for SLC NAND and NOR flashes, and 1K-10K for MLC
NAND flashes. Blocks do not have the wear-out property.
5 Eraseblocks may become bad (only on NAND flashes) and software should
deal with this. Blocks on hard drives typically do not become bad,
because hardware has mechanisms to substitute bad blocks, at least in
modern LBA disks.
It should be quite obvious why UBIFS is very different to traditional
file-systems.
UBIFS works on top of UBI. UBI is a separate software layer which may be
found in drivers/mtd/ubi. UBI is basically a volume management and
wear-leveling layer. It provides so called UBI volumes which is a higher
level abstraction than a MTD device. The programming model of UBI devices
is very similar to MTD devices - they still consist of large eraseblocks,
they have read/write/erase operations, but UBI devices are devoid of
limitations like wear and bad blocks (items 4 and 5 in the above list).
In a sense, UBIFS is a next generation of JFFS2 file-system, but it is
very different and incompatible to JFFS2. The following are the main
differences.
* JFFS2 works on top of MTD devices, UBIFS depends on UBI and works on
top of UBI volumes.
* JFFS2 does not have on-media index and has to build it while mounting,
which requires full media scan. UBIFS maintains the FS indexing
information on the flash media and does not require full media scan,
so it mounts many times faster than JFFS2.
* JFFS2 is a write-through file-system, while UBIFS supports write-back,
which makes UBIFS much faster on writes.
Similarly to JFFS2, UBIFS supports on-the-flight compression which makes
it possible to fit quite a lot of data to the flash.
Similarly to JFFS2, UBIFS is tolerant of unclean reboots and power-cuts.
It does not need stuff like ckfs.ext2. UBIFS automatically replays its
journal and recovers from crashes, ensuring that the on-flash data
structures are consistent.
UBIFS scales logarithmically (most of the data structures it uses are
trees), so the mount time and memory consumption do not linearly depend
on the flash size, like in case of JFFS2. This is because UBIFS
maintains the FS index on the flash media. However, UBIFS depends on
UBI, which scales linearly. So overall UBI/UBIFS stack scales linearly.
Nevertheless, UBI/UBIFS scales considerably better than JFFS2.
The authors of UBIFS believe, that it is possible to develop UBI2 which
would scale logarithmically as well. UBI2 would support the same API as UBI,
but it would be binary incompatible to UBI. So UBIFS would not need to be
changed to use UBI2
Mount options
=============
(*) == default.
norm_unmount (*) commit on unmount; the journal is committed
when the file-system is unmounted so that the
next mount does not have to replay the journal
and it becomes very fast;
fast_unmount do not commit on unmount; this option makes
unmount faster, but the next mount slower
because of the need to replay the journal.
Quick usage instructions
========================
The UBI volume to mount is specified using "ubiX_Y" or "ubiX:NAME" syntax,
where "X" is UBI device number, "Y" is UBI volume number, and "NAME" is
UBI volume name.
Mount volume 0 on UBI device 0 to /mnt/ubifs:
$ mount -t ubifs ubi0_0 /mnt/ubifs
Mount "rootfs" volume of UBI device 0 to /mnt/ubifs ("rootfs" is volume
name):
$ mount -t ubifs ubi0:rootfs /mnt/ubifs
The following is an example of the kernel boot arguments to attach mtd0
to UBI and mount volume "rootfs":
ubi.mtd=0 root=ubi0:rootfs rootfstype=ubifs
Module Parameters for Debugging
===============================
When UBIFS has been compiled with debugging enabled, there are 3 module
parameters that are available to control aspects of testing and debugging.
The parameters are unsigned integers where each bit controls an option.
The parameters are:
debug_msgs Selects which debug messages to display, as follows:
Message Type Flag value
General messages 1
Journal messages 2
Mount messages 4
Commit messages 8
LEB search messages 16
Budgeting messages 32
Garbage collection messages 64
Tree Node Cache (TNC) messages 128
LEB properties (lprops) messages 256
Input/output messages 512
Log messages 1024
Scan messages 2048
Recovery messages 4096
debug_chks Selects extra checks that UBIFS can do while running:
Check Flag value
General checks 1
Check Tree Node Cache (TNC) 2
Check indexing tree size 4
Check orphan area 8
Check old indexing tree 16
Check LEB properties (lprops) 32
Check leaf nodes and inodes 64
debug_tsts Selects a mode of testing, as follows:
Test mode Flag value
Force in-the-gaps method 2
Failure mode for recovery testing 4
For example, set debug_msgs to 5 to display General messages and Mount
messages.
References
==========
UBIFS documentation and FAQ/HOWTO at the MTD web site:
http://www.linux-mtd.infradead.org/doc/ubifs.html
http://www.linux-mtd.infradead.org/faq/ubifs.html

401
Documentation/ftrace.txt
Просмотреть файл

@ -2,8 +2,12 @@
========================
Copyright 2008 Red Hat Inc.
Author: Steven Rostedt <srostedt@redhat.com>
Author: Steven Rostedt <srostedt@redhat.com>
License: The GNU Free Documentation License, Version 1.2
Reviewers: Elias Oltmanns, Randy Dunlap, Andrew Morton,
John Kacur, and David Teigland.
Written for: 2.6.27-rc1
Introduction
------------
@ -15,10 +19,11 @@ issues that take place outside of user-space.
Although ftrace is the function tracer, it also includes an
infrastructure that allows for other types of tracing. Some of the
tracers that are currently in ftrace is a tracer to trace
tracers that are currently in ftrace include a tracer to trace
context switches, the time it takes for a high priority task to
run after it was woken up, the time interrupts are disabled, and
more.
more (ftrace allows for tracer plugins, which means that the list of
tracers can always grow).
The File System
@ -32,6 +37,8 @@ To mount the debugfs system:
# mkdir /debug
# mount -t debugfs nodev /debug
(Note: it is more common to mount at /sys/kernel/debug, but for simplicity
this document will use /debug)
That's it! (assuming that you have ftrace configured into your kernel)
@ -46,21 +53,20 @@ of ftrace. Here is a list of some of the key files:
that is configured.
available_tracers : This holds the different types of tracers that
has been compiled into the kernel. The tracers
listed here can be configured by echoing in their
name into current_tracer.
have been compiled into the kernel. The tracers
listed here can be configured by echoing their name
into current_tracer.
tracing_enabled : This sets or displays whether the current_tracer
is activated and tracing or not. Echo 0 into this
file to disable the tracer or 1 (or non-zero) to
enable it.
file to disable the tracer or 1 to enable it.
trace : This file holds the output of the trace in a human readable
format.
format (described below).
latency_trace : This file shows the same trace but the information
is organized more to display possible latencies
in the system.
in the system (described below).
trace_pipe : The output is the same as the "trace" file but this
file is meant to be streamed with live tracing.
@ -72,7 +78,7 @@ of ftrace. Here is a list of some of the key files:
file, it is consumed, and will not be read
again with a sequential read. The "trace" and
"latency_trace" files are static, and if the
tracer isn't adding more data, they will display
tracer is not adding more data, they will display
the same information every time they are read.
iter_ctrl : This file lets the user control the amount of data
@ -89,12 +95,14 @@ of ftrace. Here is a list of some of the key files:
trace_entries : This sets or displays the number of trace
entries each CPU buffer can hold. The tracer buffers
are the same size for each CPU, so care must be
taken when modifying the trace_entries. The number
of actually entries will be the number given
times the number of possible CPUS. The buffers
are saved as individual pages, and the actual entries
will always be rounded up to entries per page.
are the same size for each CPU. The displayed number
is the size of the CPU buffer and not total size. The
trace buffers are allocated in pages (blocks of memory
that the kernel uses for allocation, usually 4 KB in size).
Since each entry is smaller than a page, if the last
allocated page has room for more entries than were
requested, the rest of the page is used to allocate
entries.
This can only be updated when the current_tracer
is set to "none".
@ -107,20 +115,19 @@ of ftrace. Here is a list of some of the key files:
on specified CPUS. The format is a hex string
representing the CPUS.
set_ftrace_filter : When dynamic ftrace is configured in, the
code is dynamically modified to disable calling
of the function profiler (mcount). This lets
tracing be configured in with practically no overhead
in performance. This also has a side effect of
enabling or disabling specific functions to be
traced. Echoing in names of functions into this
file will limit the trace to only those files.
set_ftrace_filter : When dynamic ftrace is configured in (see the
section below "dynamic ftrace"), the code is dynamically
modified (code text rewrite) to disable calling of the
function profiler (mcount). This lets tracing be configured
in with practically no overhead in performance. This also
has a side effect of enabling or disabling specific functions
to be traced. Echoing names of functions into this file
will limit the trace to only those functions.
set_ftrace_notrace: This has the opposite effect that
set_ftrace_filter has. Any function that is added
here will not be traced. If a function exists
in both set_ftrace_filter and set_ftrace_notrace
the function will _not_ bet traced.
set_ftrace_notrace: This has an effect opposite to that of
set_ftrace_filter. Any function that is added here will not
be traced. If a function exists in both set_ftrace_filter
and set_ftrace_notrace, the function will _not_ be traced.
available_filter_functions : When a function is encountered the first
time by the dynamic tracer, it is recorded and
@ -128,32 +135,31 @@ of ftrace. Here is a list of some of the key files:
lists the functions that have been recorded
by the dynamic tracer and these functions can
be used to set the ftrace filter by the above
"set_ftrace_filter" file.
"set_ftrace_filter" file. (See the section "dynamic ftrace"
below for more details).
The Tracers
-----------
Here are the list of current tracers that can be configured.
Here is the list of current tracers that may be configured.
ftrace - function tracer that uses mcount to trace all functions.
It is possible to filter out which functions that are
traced when dynamic ftrace is configured in.
sched_switch - traces the context switches between tasks.
irqsoff - traces the areas that disable interrupts and saves off
irqsoff - traces the areas that disable interrupts and saves
the trace with the longest max latency.
See tracing_max_latency. When a new max is recorded,
it replaces the old trace. It is best to view this
trace with the latency_trace file.
trace via the latency_trace file.
preemptoff - Similar to irqsoff but traces and records the time
preemption is disabled.
preemptoff - Similar to irqsoff but traces and records the amount of
time for which preemption is disabled.
preemptirqsoff - Similar to irqsoff and preemptoff, but traces and
records the largest time irqs and/or preemption is
disabled.
records the largest time for which irqs and/or preemption
is disabled.
wakeup - Traces and records the max latency that it takes for
the highest priority task to get scheduled after
@ -166,13 +172,13 @@ Here are the list of current tracers that can be configured.
Examples of using the tracer
----------------------------
Here are typical examples of using the tracers with only controlling
them with the debugfs interface (without using any user-land utilities).
Here are typical examples of using the tracers when controlling them only
with the debugfs interface (without using any user-land utilities).
Output format:
--------------
Here's an example of the output format of the file "trace"
Here is an example of the output format of the file "trace"
--------
# tracer: ftrace
@ -184,14 +190,15 @@ Here's an example of the output format of the file "trace"
bash-4251 [01] 10152.583855: _atomic_dec_and_lock <-dput
--------
A header is printed with the trace that is represented. In this case
the tracer is "ftrace". Then a header showing the format. Task name
"bash", the task PID "4251", the CPU that it was running on
A header is printed with the tracer name that is represented by the trace.
In this case the tracer is "ftrace". Then a header showing the format. Task
name "bash", the task PID "4251", the CPU that it was running on
"01", the timestamp in <secs>.<usecs> format, the function name that was
traced "path_put" and the parent function that called this function
"path_walk".
"path_walk". The timestamp is the time at which the function was
entered.
The sched_switch tracer also includes tracing of task wake ups and
The sched_switch tracer also includes tracing of task wakeups and
context switches.
ksoftirqd/1-7 [01] 1453.070013: 7:115:R + 2916:115:S
@ -201,7 +208,7 @@ context switches.
kondemand/1-2916 [01] 1453.070013: 2916:115:S ==> 7:115:R
ksoftirqd/1-7 [01] 1453.070013: 7:115:S ==> 0:140:R
Wake ups are represented by a "+" and the context switches show
Wake ups are represented by a "+" and the context switches are shown as
"==>". The format is:
Context switches:
@ -216,7 +223,7 @@ Wake ups are represented by a "+" and the context switches show
<pid>:<prio>:<state> + <pid>:<prio>:<state>
The prio is the internal kernel priority, which is inverse to the
The prio is the internal kernel priority, which is the inverse of the
priority that is usually displayed by user-space tools. Zero represents
the highest priority (99). Prio 100 starts the "nice" priorities with
100 being equal to nice -20 and 139 being nice 19. The prio "140" is
@ -227,7 +234,7 @@ Latency trace format
--------------------
For traces that display latency times, the latency_trace file gives
a bit more information to see why a latency happened. Here's a typical
somewhat more information to see why a latency happened. Here is a typical
trace.
# tracer: irqsoff
@ -255,21 +262,20 @@ irqsoff latency trace v1.1.5 on 2.6.26-rc8
<idle>-0 0d.s1 98us : trace_hardirqs_on (do_softirq)
vim:ft=help
This shows that the current tracer is "irqsoff" tracing the time
interrupts are disabled. It gives the trace version and the kernel
this was executed on (2.6.26-rc8). Then it displays the max latency
in microsecs (97 us). The number of trace entries displayed
by the total number recorded (both are three: #3/3). The type of
This shows that the current tracer is "irqsoff" tracing the time for which
interrupts were disabled. It gives the trace version and the version
of the kernel upon which this was executed on (2.6.26-rc8). Then it displays
the max latency in microsecs (97 us). The number of trace entries displayed
and the total number recorded (both are three: #3/3). The type of
preemption that was used (PREEMPT). VP, KP, SP, and HP are always zero
and reserved for later use. #P is the number of online CPUS (#P:2).
and are reserved for later use. #P is the number of online CPUS (#P:2).
The task is the process that was running when the latency happened.
The task is the process that was running when the latency occurred.
(swapper pid: 0).
The start and stop that caused the latencies:
The start and stop (the functions in which the interrupts were disabled and
enabled respectively) that caused the latencies:
apic_timer_interrupt is where the interrupts were disabled.
do_softirq is where they were enabled again.
@ -281,14 +287,14 @@ explains which is which.
pid: The PID of that process.
CPU#: The CPU that the process was running on.
CPU#: The CPU which the process was running on.
irqs-off: 'd' interrupts are disabled. '.' otherwise.
need-resched: 'N' task need_resched is set, '.' otherwise.
hardirq/softirq:
'H' - hard irq happened inside a softirq.
'H' - hard irq occurred inside a softirq.
'h' - hard irq is running
's' - soft irq is running
'.' - normal context.
@ -297,13 +303,13 @@ explains which is which.
The above is mostly meaningful for kernel developers.
time: This differs from the trace output where as the trace output
contained a absolute timestamp. This timestamp is relative
to the start of the first entry in the the trace.
time: This differs from the trace file output. The trace file output
includes an absolute timestamp. The timestamp used by the
latency_trace file is relative to the start of the trace.
delay: This is just to help catch your eye a bit better. And
needs to be fixed to be only relative to the same CPU.
The marks is determined by the difference between this
The marks are determined by the difference between this
current trace and the next trace.
'!' - greater than preempt_mark_thresh (default 100)
'+' - greater than 1 microsecond
@ -322,13 +328,13 @@ output. To see what is available, simply cat the file:
print-parent nosym-offset nosym-addr noverbose noraw nohex nobin \
noblock nostacktrace nosched-tree
To disable one of the options, echo in the option appended with "no".
To disable one of the options, echo in the option prepended with "no".
echo noprint-parent > /debug/tracing/iter_ctrl
To enable an option, leave off the "no".
echo sym-offest > /debug/tracing/iter_ctrl
echo sym-offset > /debug/tracing/iter_ctrl
Here are the available options:
@ -344,7 +350,7 @@ Here are the available options:
sym-offset - Display not only the function name, but also the offset
in the function. For example, instead of seeing just
"ktime_get" you will see "ktime_get+0xb/0x20"
"ktime_get", you will see "ktime_get+0xb/0x20".
sym-offset:
bash-4000 [01] 1477.606694: simple_strtoul+0x6/0xa0
@ -364,7 +370,7 @@ Here are the available options:
user applications that can translate the raw numbers better than
having it done in the kernel.
hex - similar to raw, but the numbers will be in a hexadecimal format.
hex - Similar to raw, but the numbers will be in a hexadecimal format.
bin - This will print out the formats in raw binary.
@ -380,8 +386,8 @@ Here are the available options:
sched_switch
------------
This tracer simply records schedule switches. Here's an example
on how to implement it.
This tracer simply records schedule switches. Here is an example
of how to use it.
# echo sched_switch > /debug/tracing/current_tracer
# echo 1 > /debug/tracing/tracing_enabled
@ -416,8 +422,8 @@ the name of the trace and points to the options. The "FUNCTION"
is a misnomer since here it represents the wake ups and context
switches.
The sched_switch only lists the wake ups (represented with '+')
and context switches ('==>') with the previous task or current
The sched_switch file only lists the wake ups (represented with '+')
and context switches ('==>') with the previous task or current task
first followed by the next task or task waking up. The format for both
of these is PID:KERNEL-PRIO:TASK-STATE. Remember that the KERNEL-PRIO
is the inverse of the actual priority with zero (0) being the highest
@ -432,7 +438,8 @@ The task states are:
R - running : wants to run, may not actually be running
S - sleep : process is waiting to be woken up (handles signals)
D - deep sleep : process must be woken up (ignores signals)
D - disk sleep (uninterruptible sleep) : process must be woken up
(ignores signals)
T - stopped : process suspended
t - traced : process is being traced (with something like gdb)
Z - zombie : process waiting to be cleaned up
@ -442,8 +449,8 @@ The task states are:
ftrace_enabled
--------------
The following tracers give different output depending on whether
or not the sysctl ftrace_enabled is set. To set ftrace_enabled,
The following tracers (listed below) give different output depending
on whether or not the sysctl ftrace_enabled is set. To set ftrace_enabled,
one can either use the sysctl function or set it via the proc
file system interface.
@ -470,13 +477,12 @@ interrupt from triggering or the mouse interrupt from letting the
kernel know of a new mouse event. The result is a latency with the
reaction time.
The irqsoff tracer tracks the time interrupts are disabled and when
they are re-enabled. When a new maximum latency is hit, it saves off
the trace so that it may be retrieved at a later time. Every time a
new maximum in reached, the old saved trace is discarded and the new
trace is saved.
The irqsoff tracer tracks the time for which interrupts are disabled.
When a new maximum latency is hit, the tracer saves the trace leading up
to that latency point so that every time a new maximum is reached, the old
saved trace is discarded and the new trace is saved.
To reset the maximum, echo 0 into tracing_max_latency. Here's an
To reset the maximum, echo 0 into tracing_max_latency. Here is an
example:
# echo irqsoff > /debug/tracing/current_tracer
@ -488,14 +494,14 @@ example:
# cat /debug/tracing/latency_trace
# tracer: irqsoff
#
irqsoff latency trace v1.1.5 on 2.6.26-rc8
irqsoff latency trace v1.1.5 on 2.6.26
--------------------------------------------------------------------
latency: 6 us, #3/3, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2)
latency: 12 us, #3/3, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2)
-----------------
| task: bash-4269 (uid:0 nice:0 policy:0 rt_prio:0)
| task: bash-3730 (uid:0 nice:0 policy:0 rt_prio:0)
-----------------
=> started at: copy_page_range
=> ended at: copy_page_range
=> started at: sys_setpgid
=> ended at: sys_setpgid
# _------=> CPU#
# / _-----=> irqs-off
@ -506,21 +512,19 @@ irqsoff latency trace v1.1.5 on 2.6.26-rc8
# ||||| delay
# cmd pid ||||| time | caller
# \ / ||||| \ | /
bash-4269 1...1 0us+: _spin_lock (copy_page_range)
bash-4269 1...1 7us : _spin_unlock (copy_page_range)
bash-4269 1...2 7us : trace_preempt_on (copy_page_range)
bash-3730 1d... 0us : _write_lock_irq (sys_setpgid)
bash-3730 1d..1 1us+: _write_unlock_irq (sys_setpgid)
bash-3730 1d..2 14us : trace_hardirqs_on (sys_setpgid)
vim:ft=help
Here we see that that we had a latency of 12 microsecs (which is
very good). The _write_lock_irq in sys_setpgid disabled interrupts.
The difference between the 12 and the displayed timestamp 14us occurred
because the clock was incremented between the time of recording the max
latency and the time of recording the function that had that latency.
Here we see that that we had a latency of 6 microsecs (which is
very good). The spin_lock in copy_page_range disabled interrupts.
The difference between the 6 and the displayed timestamp 7us is
because the clock must have incremented between the time of recording
the max latency and recording the function that had that latency.
Note the above had ftrace_enabled not set. If we set the ftrace_enabled
we get a much larger output:
Note the above example had ftrace_enabled not set. If we set the
ftrace_enabled, we get a much larger output:
# tracer: irqsoff
#
@ -566,27 +570,26 @@ irqsoff latency trace v1.1.5 on 2.6.26-rc8
ls-4339 0d..2 51us : trace_hardirqs_on (__alloc_pages_internal)
vim:ft=help
Here we traced a 50 microsecond latency. But we also see all the
functions that were called during that time. Note that enabling
function tracing we endure an added overhead. This overhead may
extend the latency times. But never the less, this trace has provided
some very helpful debugging.
functions that were called during that time. Note that by enabling
function tracing, we incur an added overhead. This overhead may
extend the latency times. But nevertheless, this trace has provided
some very helpful debugging information.
preemptoff
----------
When preemption is disabled we may be able to receive interrupts but
the task can not be preempted and a higher priority task must wait
When preemption is disabled, we may be able to receive interrupts but
the task cannot be preempted and a higher priority task must wait
for preemption to be enabled again before it can preempt a lower
priority task.
The preemptoff tracer traces the places that disables preemption.
Like the irqsoff, it records the maximum latency that preemption
was disabled. The control of preemptoff is much like the irqsoff.
The preemptoff tracer traces the places that disable preemption.
Like the irqsoff tracer, it records the maximum latency for which preemption
was disabled. The control of preemptoff tracer is much like the irqsoff
tracer.
# echo preemptoff > /debug/tracing/current_tracer
# echo 0 > /debug/tracing/tracing_max_latency
@ -620,8 +623,6 @@ preemptoff latency trace v1.1.5 on 2.6.26-rc8
sshd-4261 0d.s1 30us : trace_preempt_on (__do_softirq)
vim:ft=help
This has some more changes. Preemption was disabled when an interrupt
came in (notice the 'h'), and was enabled while doing a softirq.
(notice the 's'). But we also see that interrupts have been disabled
@ -689,16 +690,16 @@ The above is an example of the preemptoff trace with ftrace_enabled
set. Here we see that interrupts were disabled the entire time.
The irq_enter code lets us know that we entered an interrupt 'h'.
Before that, the functions being traced still show that it is not
in an interrupt, but we can see by the functions themselves that
in an interrupt, but we can see from the functions themselves that
this is not the case.
Notice that the __do_softirq when called doesn't have a preempt_count.
It may seem that we missed a preempt enabled. What really happened
is that the preempt count is held on the threads stack and we
Notice that __do_softirq when called does not have a preempt_count.
It may seem that we missed a preempt enabling. What really happened
is that the preempt count is held on the thread's stack and we
switched to the softirq stack (4K stacks in effect). The code
does not copy the preempt count, but because interrupts are disabled
we don't need to worry about it. Having a tracer like this is good
to let people know what really happens inside the kernel.
does not copy the preempt count, but because interrupts are disabled,
we do not need to worry about it. Having a tracer like this is good
for letting people know what really happens inside the kernel.
preemptirqsoff
@ -708,7 +709,7 @@ Knowing the locations that have interrupts disabled or preemption
disabled for the longest times is helpful. But sometimes we would
like to know when either preemption and/or interrupts are disabled.
The following code:
Consider the following code:
local_irq_disable();
call_function_with_irqs_off();
@ -732,7 +733,7 @@ To record this time, use the preemptirqsoff tracer.
Again, using this trace is much like the irqsoff and preemptoff tracers.
# echo preemptoff > /debug/tracing/current_tracer
# echo preemptirqsoff > /debug/tracing/current_tracer
# echo 0 > /debug/tracing/tracing_max_latency
# echo 1 > /debug/tracing/tracing_enabled
# ls -ltr
@ -764,12 +765,10 @@ preemptirqsoff latency trace v1.1.5 on 2.6.26-rc8
ls-4860 0d.s1 294us : trace_preempt_on (__do_softirq)
vim:ft=help
The trace_hardirqs_off_thunk is called from assembly on x86 when
interrupts are disabled in the assembly code. Without the function
tracing, we don't know if interrupts were enabled within the preemption
tracing, we do not know if interrupts were enabled within the preemption
points. We do see that it started with preemption enabled.
Here is a trace with ftrace_enabled set:
@ -860,25 +859,25 @@ preemptirqsoff latency trace v1.1.5 on 2.6.26-rc8
This is a very interesting trace. It started with the preemption of
the ls task. We see that the task had the "need_resched" bit set
with the 'N' in the trace. Interrupts are disabled in the spin_lock
and the trace started. We see that a schedule took place to run
sshd. When the interrupts were enabled we took an interrupt.
On return of the interrupt the softirq ran. We took another interrupt
while running the softirq as we see with the capital 'H'.
via the 'N' in the trace. Interrupts were disabled before the spin_lock
at the beginning of the trace. We see that a schedule took place to run
sshd. When the interrupts were enabled, we took an interrupt.
On return from the interrupt handler, the softirq ran. We took another
interrupt while running the softirq as we see from the capital 'H'.
wakeup
------
In Real-Time environment it is very important to know the wakeup
time it takes for the highest priority task that wakes up to the
time it executes. This is also known as "schedule latency".
In a Real-Time environment it is very important to know the wakeup
time it takes for the highest priority task that is woken up to the
time that it executes. This is also known as "schedule latency".
I stress the point that this is about RT tasks. It is also important
to know the scheduling latency of non-RT tasks, but the average
schedule latency is better for non-RT tasks. Tools like
LatencyTop is more appropriate for such measurements.
LatencyTop are more appropriate for such measurements.
Real-Time environments is interested in the worst case latency.
Real-Time environments are interested in the worst case latency.
That is the longest latency it takes for something to happen, and
not the average. We can have a very fast scheduler that may only
have a large latency once in a while, but that would not work well
@ -889,8 +888,8 @@ tasks that are unpredictable will overwrite the worst case latency
of RT tasks.
Since this tracer only deals with RT tasks, we will run this slightly
different than we did with the previous tracers. Instead of performing
an 'ls' we will run 'sleep 1' under 'chrt' which changes the
differently than we did with the previous tracers. Instead of performing
an 'ls', we will run 'sleep 1' under 'chrt' which changes the
priority of the task.
# echo wakeup > /debug/tracing/current_tracer
@ -921,12 +920,10 @@ wakeup latency trace v1.1.5 on 2.6.26-rc8
<idle>-0 1d..4 4us : schedule (cpu_idle)
vim:ft=help
Running this on an idle system we see that it only took 4 microseconds
Running this on an idle system, we see that it only took 4 microseconds
to perform the task switch. Note, since the trace marker in the
schedule is before the actual "switch" we stop the tracing when
schedule is before the actual "switch", we stop the tracing when
the recorded task is about to schedule in. This may change if
we add a new marker at the end of the scheduler.
@ -991,13 +988,16 @@ ksoftirq-7 1d..6 49us : sub_preempt_count (_spin_unlock)
ksoftirq-7 1d..4 50us : schedule (__cond_resched)
The interrupt went off while running ksoftirqd. This task runs at
SCHED_OTHER. Why didn't we see the 'N' set early? This may be
a harmless bug with x86_32 and 4K stacks. The need_reched() function
that tests if we need to reschedule looks on the actual stack.
Where as the setting of the NEED_RESCHED bit happens on the
task's stack. But because we are in a hard interrupt, the test
is with the interrupts stack which has that to be false. We don't
see the 'N' until we switch back to the task's stack.
SCHED_OTHER. Why did not we see the 'N' set early? This may be
a harmless bug with x86_32 and 4K stacks. On x86_32 with 4K stacks
configured, the interrupt and softirq run with their own stack.
Some information is held on the top of the task's stack (need_resched
and preempt_count are both stored there). The setting of the NEED_RESCHED
bit is done directly to the task's stack, but the reading of the
NEED_RESCHED is done by looking at the current stack, which in this case
is the stack for the hard interrupt. This hides the fact that NEED_RESCHED
has been set. We do not see the 'N' until we switch back to the task's
assigned stack.
ftrace
------
@ -1036,14 +1036,14 @@ this tracer is a nop.
[...]
Note: It is sometimes better to enable or disable tracing directly from
a program, because the buffer may be overflowed by the echo commands
before you get to the point you want to trace. It is also easier to
stop the tracing at the point that you hit the part that you are
interested in. Since the ftrace buffer is a ring buffer with the
oldest data being overwritten, usually it is sufficient to start the
tracer with an echo command but have you code stop it. Something
like the following is usually appropriate for this.
Note: ftrace uses ring buffers to store the above entries. The newest data
may overwrite the oldest data. Sometimes using echo to stop the trace
is not sufficient because the tracing could have overwritten the data
that you wanted to record. For this reason, it is sometimes better to
disable tracing directly from a program. This allows you to stop the
tracing at the point that you hit the part that you are interested in.
To disable the tracing directly from a C program, something like following
code snippet can be used:
int trace_fd;
[...]
@ -1052,25 +1052,31 @@ int main(int argc, char *argv[]) {
trace_fd = open("/debug/tracing/tracing_enabled", O_WRONLY);
[...]
if (condition_hit()) {
write(trace_fd, "0", 1);
write(trace_fd, "0", 1);
}
[...]
}
Note: Here we hard coded the path name. The debugfs mount is not
guaranteed to be at /debug (and is more commonly at /sys/kernel/debug).
For simple one time traces, the above is sufficent. For anything else,
a search through /proc/mounts may be needed to find where the debugfs
file-system is mounted.
dynamic ftrace
--------------
If CONFIG_DYNAMIC_FTRACE is set, then the system will run with
If CONFIG_DYNAMIC_FTRACE is set, the system will run with
virtually no overhead when function tracing is disabled. The way
this works is the mcount function call (placed at the start of
every kernel function, produced by the -pg switch in gcc), starts
of pointing to a simple return.
of pointing to a simple return. (Enabling FTRACE will include the
-pg switch in the compiling of the kernel.)
When dynamic ftrace is initialized, it calls kstop_machine to make it
act like a uniprocessor so that it can freely modify code without
worrying about other processors executing that same code. At
initialization, the mcount calls are change to call a "record_ip"
When dynamic ftrace is initialized, it calls kstop_machine to make
the machine act like a uniprocessor so that it can freely modify code
without worrying about other processors executing that same code. At
initialization, the mcount calls are changed to call a "record_ip"
function. After this, the first time a kernel function is called,
it has the calling address saved in a hash table.
@ -1078,15 +1084,15 @@ Later on the ftraced kernel thread is awoken and will again call
kstop_machine if new functions have been recorded. The ftraced thread
will change all calls to mcount to "nop". Just calling mcount
and having mcount return has shown a 10% overhead. By converting
it to a nop, there is no recordable overhead to the system.
it to a nop, there is no measurable overhead to the system.
One special side-effect to the recording of the functions being
traced, is that we can now selectively choose which functions we
want to trace and which ones we want the mcount calls to remain as
traced is that we can now selectively choose which functions we
wish to trace and which ones we want the mcount calls to remain as
nops.
Two files that contain to the enabling and disabling of recorded
functions are:
Two files are used, one for enabling and one for disabling the tracing
of specified functions. They are:
set_ftrace_filter
@ -1094,7 +1100,7 @@ and
set_ftrace_notrace
A list of available functions that you can add to this files is listed
A list of available functions that you can add to these files is listed
in:
available_filter_functions
@ -1108,7 +1114,7 @@ pick_next_task_fair
mutex_lock
[...]
If I'm only interested in sys_nanosleep and hrtimer_interrupt:
If I am only interested in sys_nanosleep and hrtimer_interrupt:
# echo sys_nanosleep hrtimer_interrupt \
> /debug/tracing/set_ftrace_filter
@ -1125,21 +1131,21 @@ If I'm only interested in sys_nanosleep and hrtimer_interrupt:
usleep-4134 [00] 1317.070111: sys_nanosleep <-syscall_call
<idle>-0 [00] 1317.070115: hrtimer_interrupt <-smp_apic_timer_interrupt
To see what functions are being traced, you can cat the file:
To see which functions are being traced, you can cat the file:
# cat /debug/tracing/set_ftrace_filter
hrtimer_interrupt
sys_nanosleep
Perhaps this isn't enough. The filters also allow simple wild cards.
Only the following is currently available
Perhaps this is not enough. The filters also allow simple wild cards.
Only the following are currently available
<match>* - will match functions that begins with <match>
<match>* - will match functions that begin with <match>
*<match> - will match functions that end with <match>
*<match>* - will match functions that have <match> in it
Thats all the wild cards that are allowed.
These are the only wild cards which are supported.
<match>*<match> will not work.
@ -1187,7 +1193,7 @@ This is because the '>' and '>>' act just like they do in bash.
To rewrite the filters, use '>'
To append to the filters, use '>>'
To clear out a filter so that all functions will be recorded again.
To clear out a filter so that all functions will be recorded again:
# echo > /debug/tracing/set_ftrace_filter
# cat /debug/tracing/set_ftrace_filter
@ -1246,24 +1252,24 @@ ftraced
As mentioned above, when dynamic ftrace is configured in, a kernel
thread wakes up once a second and checks to see if there are mcount
calls that need to be converted into nops. If there is not, then
it simply goes back to sleep. But if there is, it will call
calls that need to be converted into nops. If there are not any, then
it simply goes back to sleep. But if there are some, it will call
kstop_machine to convert the calls to nops.
There may be a case that you do not want this added latency.
There may be a case in which you do not want this added latency.
Perhaps you are doing some audio recording and this activity might
cause skips in the playback. There is an interface to disable
and enable the ftraced kernel thread.
and enable the "ftraced" kernel thread.
# echo 0 > /debug/tracing/ftraced_enabled
This will disable the calling of the kstop_machine to update the
mcount calls to nops. Remember that there's a large overhead
This will disable the calling of kstop_machine to update the
mcount calls to nops. Remember that there is a large overhead
to calling mcount. Without this kernel thread, that overhead will
exist.
Any write to the ftraced_enabled file will cause the kstop_machine
to run if there are recorded calls to mcount. This means that a
If there are recorded calls to mcount, any write to the ftraced_enabled
file will cause the kstop_machine to run. This means that a
user can manually perform the updates when they want to by simply
echoing a '0' into the ftraced_enabled file.
@ -1274,8 +1280,8 @@ that uses ftrace function recording.
trace_pipe
----------
The trace_pipe outputs the same as trace, but the effect on the
tracing is different. Every read from trace_pipe is consumed.
The trace_pipe outputs the same content as the trace file, but the effect
on the tracing is different. Every read from trace_pipe is consumed.
This means that subsequent reads will be different. The trace
is live.
@ -1305,7 +1311,7 @@ is live.
bash-4043 [00] 41.267111: select_task_rq_rt <-try_to_wake_up
Note, reading the trace_pipe will block until more input is added.
Note, reading the trace_pipe file will block until more input is added.
By changing the tracer, trace_pipe will issue an EOF. We needed
to set the ftrace tracer _before_ cating the trace_pipe file.
@ -1314,8 +1320,8 @@ trace entries
-------------
Having too much or not enough data can be troublesome in diagnosing
some issue in the kernel. The file trace_entries is used to modify
the size of the internal trace buffers. The numbers listed
an issue in the kernel. The file trace_entries is used to modify
the size of the internal trace buffers. The number listed
is the number of entries that can be recorded per CPU. To know
the full size, multiply the number of possible CPUS with the
number of entries.
@ -1323,8 +1329,9 @@ number of entries.
# cat /debug/tracing/trace_entries
65620
Note, to modify this you must have tracing fulling disabled. To do that,
echo "none" into the current_tracer.
Note, to modify this, you must have tracing completely disabled. To do that,
echo "none" into the current_tracer. If the current_tracer is not set
to "none", an EINVAL error will be returned.
# echo none > /debug/tracing/current_tracer
# echo 100000 > /debug/tracing/trace_entries
@ -1333,18 +1340,18 @@ echo "none" into the current_tracer.
Notice that we echoed in 100,000 but the size is 100,045. The entries
are held by individual pages. It allocates the number of pages it takes
are held in individual pages. It allocates the number of pages it takes
to fulfill the request. If more entries may fit on the last page
it will add them.
then they will be added.
# echo 1 > /debug/tracing/trace_entries
# cat /debug/tracing/trace_entries
85
This shows us that 85 entries can fit on a single page.
This shows us that 85 entries can fit in a single page.
The number of pages that will be allocated is a percentage of available
memory. Allocating too much will produces an error.
The number of pages which will be allocated is limited to a percentage
of available memory. Allocating too much will produce an error.
# echo 1000000000000 > /debug/tracing/trace_entries
-bash: echo: write error: Cannot allocate memory

47
Documentation/i2c/busses/i2c-i810
Просмотреть файл

@ -1,47 +0,0 @@
Kernel driver i2c-i810
Supported adapters:
* Intel 82810, 82810-DC100, 82810E, and 82815 (GMCH)
* Intel 82845G (GMCH)
Authors:
Frodo Looijaard <frodol@dds.nl>,
Philip Edelbrock <phil@netroedge.com>,
Kyösti Mälkki <kmalkki@cc.hut.fi>,
Ralph Metzler <rjkm@thp.uni-koeln.de>,
Mark D. Studebaker <mdsxyz123@yahoo.com>
Main contact: Mark Studebaker <mdsxyz123@yahoo.com>
Description
-----------
WARNING: If you have an '810' or '815' motherboard, your standard I2C
temperature sensors are most likely on the 801's I2C bus. You want the
i2c-i801 driver for those, not this driver.
Now for the i2c-i810...
The GMCH chip contains two I2C interfaces.
The first interface is used for DDC (Data Display Channel) which is a
serial channel through the VGA monitor connector to a DDC-compliant
monitor. This interface is defined by the Video Electronics Standards
Association (VESA). The standards are available for purchase at
http://www.vesa.org .
The second interface is a general-purpose I2C bus. It may be connected to a
TV-out chip such as the BT869 or possibly to a digital flat-panel display.
Features
--------
Both busses use the i2c-algo-bit driver for 'bit banging'
and support for specific transactions is provided by i2c-algo-bit.
Issues
------
If you enable bus testing in i2c-algo-bit (insmod i2c-algo-bit bit_test=1),
the test may fail; if so, the i2c-i810 driver won't be inserted. However,
we think this has been fixed.

23
Documentation/i2c/busses/i2c-prosavage
Просмотреть файл

@ -1,23 +0,0 @@
Kernel driver i2c-prosavage
Supported adapters:
S3/VIA KM266/VT8375 aka ProSavage8
S3/VIA KM133/VT8365 aka Savage4
Author: Henk Vergonet <henk@god.dyndns.org>
Description
-----------
The Savage4 chips contain two I2C interfaces (aka a I2C 'master' or
'host').
The first interface is used for DDC (Data Display Channel) which is a
serial channel through the VGA monitor connector to a DDC-compliant
monitor. This interface is defined by the Video Electronics Standards
Association (VESA). The standards are available for purchase at
http://www.vesa.org . The second interface is a general-purpose I2C bus.
Usefull for gaining access to the TV Encoder chips.

26
Documentation/i2c/busses/i2c-savage4
Просмотреть файл

@ -1,26 +0,0 @@
Kernel driver i2c-savage4
Supported adapters:
* Savage4
* Savage2000
Authors:
Alexander Wold <awold@bigfoot.com>,
Mark D. Studebaker <mdsxyz123@yahoo.com>
Description
-----------
The Savage4 chips contain two I2C interfaces (aka a I2C 'master'
or 'host').
The first interface is used for DDC (Data Display Channel) which is a
serial channel through the VGA monitor connector to a DDC-compliant
monitor. This interface is defined by the Video Electronics Standards
Association (VESA). The standards are available for purchase at
http://www.vesa.org . The DDC bus is not yet supported because its register
is not directly memory-mapped.
The second interface is a general-purpose I2C bus. This is the only
interface supported by the driver at the moment.

2
Documentation/i2c/chips/max6875
Просмотреть файл

@ -49,7 +49,7 @@ $ modprobe max6875 force=0,0x50
The MAX6874/MAX6875 ignores address bit 0, so this driver attaches to multiple
addresses. For example, for address 0x50, it also reserves 0x51.
The even-address instance is called 'max6875', the odd one is 'max6875 subclient'.
The even-address instance is called 'max6875', the odd one is 'dummy'.
Programming the chip using i2c-dev

10
Documentation/i2c/chips/pca9539
Просмотреть файл

@ -7,7 +7,7 @@ drivers/gpio/pca9539.c instead.
Supported chips:
* Philips PCA9539
Prefix: 'pca9539'
Addresses scanned: 0x74 - 0x77
Addresses scanned: none
Datasheet:
http://www.semiconductors.philips.com/acrobat/datasheets/PCA9539_2.pdf
@ -23,6 +23,14 @@ The input sense can also be inverted.
The 16 lines are split between two bytes.
Detection
---------
The PCA9539 is difficult to detect and not commonly found in PC machines,
so you have to pass the I2C bus and address of the installed PCA9539
devices explicitly to the driver at load time via the force=... parameter.
Sysfs entries
-------------

12
Documentation/i2c/chips/pcf8574
Просмотреть файл

@ -4,13 +4,13 @@ Kernel driver pcf8574
Supported chips:
* Philips PCF8574
Prefix: 'pcf8574'
Addresses scanned: I2C 0x20 - 0x27
Addresses scanned: none
Datasheet: Publicly available at the Philips Semiconductors website
http://www.semiconductors.philips.com/pip/PCF8574P.html
* Philips PCF8574A
Prefix: 'pcf8574a'
Addresses scanned: I2C 0x38 - 0x3f
Addresses scanned: none
Datasheet: Publicly available at the Philips Semiconductors website
http://www.semiconductors.philips.com/pip/PCF8574P.html
@ -38,12 +38,10 @@ For more informations see the datasheet.
Accessing PCF8574(A) via /sys interface
-------------------------------------
! Be careful !
The PCF8574(A) is plainly impossible to detect ! Stupid chip.
So every chip with address in the interval [20..27] and [38..3f] are
detected as PCF8574(A). If you have other chips in this address
range, the workaround is to load this module after the one
for your others chips.
So, you have to pass the I2C bus and address of the installed PCF857A
and PCF8574A devices explicitly to the driver at load time via the
force=... parameter.
On detection (i.e. insmod, modprobe et al.), directories are being
created for each detected PCF8574(A):

9
Documentation/i2c/chips/pcf8575
Просмотреть файл

@ -40,12 +40,9 @@ Detection
---------
There is no method known to detect whether a chip on a given I2C address is
a PCF8575 or whether it is any other I2C device. So there are two alternatives
to let the driver find the installed PCF8575 devices:
- Load this driver after any other I2C driver for I2C devices with addresses
in the range 0x20 .. 0x27.
- Pass the I2C bus and address of the installed PCF8575 devices explicitly to
the driver at load time via the probe=... or force=... parameters.
a PCF8575 or whether it is any other I2C device, so you have to pass the I2C
bus and address of the installed PCF8575 devices explicitly to the driver at
load time via the force=... parameter.
/sys interface
--------------

127
Documentation/i2c/fault-codes Normal file
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@ -0,0 +1,127 @@
This is a summary of the most important conventions for use of fault
codes in the I2C/SMBus stack.
A "Fault" is not always an "Error"
----------------------------------
Not all fault reports imply errors; "page faults" should be a familiar
example. Software often retries idempotent operations after transient
faults. There may be fancier recovery schemes that are appropriate in
some cases, such as re-initializing (and maybe resetting). After such
recovery, triggered by a fault report, there is no error.
In a similar way, sometimes a "fault" code just reports one defined
result for an operation ... it doesn't indicate that anything is wrong
at all, just that the outcome wasn't on the "golden path".
In short, your I2C driver code may need to know these codes in order
to respond correctly. Other code may need to rely on YOUR code reporting
the right fault code, so that it can (in turn) behave correctly.
I2C and SMBus fault codes
-------------------------
These are returned as negative numbers from most calls, with zero or
some positive number indicating a non-fault return. The specific
numbers associated with these symbols differ between architectures,
though most Linux systems use <asm-generic/errno*.h> numbering.
Note that the descriptions here are not exhaustive. There are other
codes that may be returned, and other cases where these codes should
be returned. However, drivers should not return other codes for these
cases (unless the hardware doesn't provide unique fault reports).
Also, codes returned by adapter probe methods follow rules which are
specific to their host bus (such as PCI, or the platform bus).
EAGAIN
Returned by I2C adapters when they lose arbitration in master
transmit mode: some other master was transmitting different
data at the same time.
Also returned when trying to invoke an I2C operation in an
atomic context, when some task is already using that I2C bus
to execute some other operation.
EBADMSG
Returned by SMBus logic when an invalid Packet Error Code byte
is received. This code is a CRC covering all bytes in the
transaction, and is sent before the terminating STOP. This
fault is only reported on read transactions; the SMBus slave
may have a way to report PEC mismatches on writes from the
host. Note that even if PECs are in use, you should not rely
on these as the only way to detect incorrect data transfers.
EBUSY
Returned by SMBus adapters when the bus was busy for longer
than allowed. This usually indicates some device (maybe the
SMBus adapter) needs some fault recovery (such as resetting),
or that the reset was attempted but failed.
EINVAL
This rather vague error means an invalid parameter has been
detected before any I/O operation was started. Use a more
specific fault code when you can.
One example would be a driver trying an SMBus Block Write
with block size outside the range of 1-32 bytes.
EIO
This rather vague error means something went wrong when
performing an I/O operation. Use a more specific fault
code when you can.
ENODEV
Returned by driver probe() methods. This is a bit more
specific than ENXIO, implying the problem isn't with the
address, but with the device found there. Driver probes
may verify the device returns *correct* responses, and
return this as appropriate. (The driver core will warn
about probe faults other than ENXIO and ENODEV.)
ENOMEM
Returned by any component that can't allocate memory when
it needs to do so.
ENXIO
Returned by I2C adapters to indicate that the address phase
of a transfer didn't get an ACK. While it might just mean
an I2C device was temporarily not responding, usually it
means there's nothing listening at that address.
Returned by driver probe() methods to indicate that they
found no device to bind to. (ENODEV may also be used.)
EOPNOTSUPP
Returned by an adapter when asked to perform an operation
that it doesn't, or can't, support.
For example, this would be returned when an adapter that
doesn't support SMBus block transfers is asked to execute
one. In that case, the driver making that request should
have verified that functionality was supported before it
made that block transfer request.
Similarly, if an I2C adapter can't execute all legal I2C
messages, it should return this when asked to perform a
transaction it can't. (These limitations can't be seen in
the adapter's functionality mask, since the assumption is
that if an adapter supports I2C it supports all of I2C.)
EPROTO
Returned when slave does not conform to the relevant I2C
or SMBus (or chip-specific) protocol specifications. One
case is when the length of an SMBus block data response
(from the SMBus slave) is outside the range 1-32 bytes.
ETIMEDOUT
This is returned by drivers when an operation took too much
time, and was aborted before it completed.
SMBus adapters may return it when an operation took more
time than allowed by the SMBus specification; for example,
when a slave stretches clocks too far. I2C has no such
timeouts, but it's normal for I2C adapters to impose some
arbitrary limits (much longer than SMBus!) too.

4
Documentation/i2c/smbus-protocol
Просмотреть файл

@ -42,8 +42,8 @@ Count (8 bits): A data byte containing the length of a block operation.
[..]: Data sent by I2C device, as opposed to data sent by the host adapter.
SMBus Quick Command: i2c_smbus_write_quick()
=============================================
SMBus Quick Command
===================
This sends a single bit to the device, at the place of the Rd/Wr bit.

51
Documentation/i2c/writing-clients
Просмотреть файл

@ -44,6 +44,10 @@ static struct i2c_driver foo_driver = {
.id_table = foo_ids,
.probe = foo_probe,
.remove = foo_remove,
/* if device autodetection is needed: */
.class = I2C_CLASS_SOMETHING,
.detect = foo_detect,
.address_data = &addr_data,
/* else, driver uses "legacy" binding model: */
.attach_adapter = foo_attach_adapter,
@ -217,6 +221,31 @@ in the I2C bus driver. You may want to save the returned i2c_client
reference for later use.
Device Detection (Standard driver model)
----------------------------------------
Sometimes you do not know in advance which I2C devices are connected to
a given I2C bus. This is for example the case of hardware monitoring
devices on a PC's SMBus. In that case, you may want to let your driver
detect supported devices automatically. This is how the legacy model
was working, and is now available as an extension to the standard
driver model (so that we can finally get rid of the legacy model.)
You simply have to define a detect callback which will attempt to
identify supported devices (returning 0 for supported ones and -ENODEV
for unsupported ones), a list of addresses to probe, and a device type
(or class) so that only I2C buses which may have that type of device
connected (and not otherwise enumerated) will be probed. The i2c
core will then call you back as needed and will instantiate a device
for you for every successful detection.
Note that this mechanism is purely optional and not suitable for all
devices. You need some reliable way to identify the supported devices
(typically using device-specific, dedicated identification registers),
otherwise misdetections are likely to occur and things can get wrong
quickly.
Device Deletion (Standard driver model)
---------------------------------------
@ -569,7 +598,6 @@ SMBus communication
in terms of it. Never use this function directly!
extern s32 i2c_smbus_write_quick(struct i2c_client * client, u8 value);
extern s32 i2c_smbus_read_byte(struct i2c_client * client);
extern s32 i2c_smbus_write_byte(struct i2c_client * client, u8 value);
extern s32 i2c_smbus_read_byte_data(struct i2c_client * client, u8 command);
@ -578,30 +606,31 @@ SMBus communication
extern s32 i2c_smbus_read_word_data(struct i2c_client * client, u8 command);
extern s32 i2c_smbus_write_word_data(struct i2c_client * client,
u8 command, u16 value);
extern s32 i2c_smbus_read_block_data(struct i2c_client * client,
u8 command, u8 *values);
extern s32 i2c_smbus_write_block_data(struct i2c_client * client,
u8 command, u8 length,
u8 *values);
extern s32 i2c_smbus_read_i2c_block_data(struct i2c_client * client,
u8 command, u8 length, u8 *values);
These ones were removed in Linux 2.6.10 because they had no users, but could
be added back later if needed:
extern s32 i2c_smbus_read_block_data(struct i2c_client * client,
u8 command, u8 *values);
extern s32 i2c_smbus_write_i2c_block_data(struct i2c_client * client,
u8 command, u8 length,
u8 *values);
These ones were removed from i2c-core because they had no users, but could
be added back later if needed:
extern s32 i2c_smbus_write_quick(struct i2c_client * client, u8 value);
extern s32 i2c_smbus_process_call(struct i2c_client * client,
u8 command, u16 value);
extern s32 i2c_smbus_block_process_call(struct i2c_client *client,
u8 command, u8 length,
u8 *values)
All these transactions return -1 on failure. The 'write' transactions
return 0 on success; the 'read' transactions return the read value, except
for read_block, which returns the number of values read. The block buffers
need not be longer than 32 bytes.
All these transactions return a negative errno value on failure. The 'write'
transactions return 0 on success; the 'read' transactions return the read
value, except for block transactions, which return the number of values
read. The block buffers need not be longer than 32 bytes.
You can read the file `smbus-protocol' for more information about the
actual SMBus protocol.

137
Documentation/ia64/paravirt_ops.txt Normal file
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@ -0,0 +1,137 @@
Paravirt_ops on IA64
====================
21 May 2008, Isaku Yamahata <yamahata@valinux.co.jp>
Introduction
------------
The aim of this documentation is to help with maintainability and/or to
encourage people to use paravirt_ops/IA64.
paravirt_ops (pv_ops in short) is a way for virtualization support of
Linux kernel on x86. Several ways for virtualization support were
proposed, paravirt_ops is the winner.
On the other hand, now there are also several IA64 virtualization
technologies like kvm/IA64, xen/IA64 and many other academic IA64
hypervisors so that it is good to add generic virtualization
infrastructure on Linux/IA64.
What is paravirt_ops?
---------------------
It has been developed on x86 as virtualization support via API, not ABI.
It allows each hypervisor to override operations which are important for
hypervisors at API level. And it allows a single kernel binary to run on
all supported execution environments including native machine.
Essentially paravirt_ops is a set of function pointers which represent
operations corresponding to low level sensitive instructions and high
level functionalities in various area. But one significant difference
from usual function pointer table is that it allows optimization with
binary patch. It is because some of these operations are very
performance sensitive and indirect call overhead is not negligible.
With binary patch, indirect C function call can be transformed into
direct C function call or in-place execution to eliminate the overhead.
Thus, operations of paravirt_ops are classified into three categories.
- simple indirect call
These operations correspond to high level functionality so that the
overhead of indirect call isn't very important.
- indirect call which allows optimization with binary patch
Usually these operations correspond to low level instructions. They
are called frequently and performance critical. So the overhead is
very important.
- a set of macros for hand written assembly code
Hand written assembly codes (.S files) also need paravirtualization
because they include sensitive instructions or some of code paths in
them are very performance critical.
The relation to the IA64 machine vector
---------------------------------------
Linux/IA64 has the IA64 machine vector functionality which allows the
kernel to switch implementations (e.g. initialization, ipi, dma api...)
depending on executing platform.
We can replace some implementations very easily defining a new machine
vector. Thus another approach for virtualization support would be
enhancing the machine vector functionality.
But paravirt_ops approach was taken because
- virtualization support needs wider support than machine vector does.
e.g. low level instruction paravirtualization. It must be
initialized very early before platform detection.
- virtualization support needs more functionality like binary patch.
Probably the calling overhead might not be very large compared to the
emulation overhead of virtualization. However in the native case, the
overhead should be eliminated completely.
A single kernel binary should run on each environment including native,
and the overhead of paravirt_ops on native environment should be as
small as possible.
- for full virtualization technology, e.g. KVM/IA64 or
Xen/IA64 HVM domain, the result would be
(the emulated platform machine vector. probably dig) + (pv_ops).
This means that the virtualization support layer should be under
the machine vector layer.
Possibly it might be better to move some function pointers from
paravirt_ops to machine vector. In fact, Xen domU case utilizes both
pv_ops and machine vector.
IA64 paravirt_ops
-----------------
In this section, the concrete paravirt_ops will be discussed.
Because of the architecture difference between ia64 and x86, the
resulting set of functions is very different from x86 pv_ops.
- C function pointer tables
They are not very performance critical so that simple C indirect
function call is acceptable. The following structures are defined at
this moment. For details see linux/include/asm-ia64/paravirt.h
- struct pv_info
This structure describes the execution environment.
- struct pv_init_ops
This structure describes the various initialization hooks.
- struct pv_iosapic_ops
This structure describes hooks to iosapic operations.
- struct pv_irq_ops
This structure describes hooks to irq related operations
- struct pv_time_op
This structure describes hooks to steal time accounting.
- a set of indirect calls which need optimization
Currently this class of functions correspond to a subset of IA64
intrinsics. At this moment the optimization with binary patch isn't
implemented yet.
struct pv_cpu_op is defined. For details see
linux/include/asm-ia64/paravirt_privop.h
Mostly they correspond to ia64 intrinsics 1-to-1.
Caveat: Now they are defined as C indirect function pointers, but in
order to support binary patch optimization, they will be changed
using GCC extended inline assembly code.
- a set of macros for hand written assembly code (.S files)
For maintenance purpose, the taken approach for .S files is single
source code and compile multiple times with different macros definitions.
Each pv_ops instance must define those macros to compile.
The important thing here is that sensitive, but non-privileged
instructions must be paravirtualized and that some privileged
instructions also need paravirtualization for reasonable performance.
Developers who modify .S files must be aware of that. At this moment
an easy checker is implemented to detect paravirtualization breakage.
But it doesn't cover all the cases.
Sometimes this set of macros is called pv_cpu_asm_op. But there is no
corresponding structure in the source code.
Those macros mostly 1:1 correspond to a subset of privileged
instructions. See linux/include/asm-ia64/native/inst.h.
And some functions written in assembly also need to be overrided so
that each pv_ops instance have to define some macros. Again see
linux/include/asm-ia64/native/inst.h.
Those structures must be initialized very early before start_kernel.
Probably initialized in head.S using multi entry point or some other trick.
For native case implementation see linux/arch/ia64/kernel/paravirt.c.

2
Documentation/input/gameport-programming.txt
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@ -1,5 +1,3 @@
$Id: gameport-programming.txt,v 1.3 2001/04/24 13:51:37 vojtech Exp $
Programming gameport drivers
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

1
Documentation/input/input.txt
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@ -1,7 +1,6 @@
Linux Input drivers v1.0
(c) 1999-2001 Vojtech Pavlik <vojtech@ucw.cz>
Sponsored by SuSE
$Id: input.txt,v 1.8 2002/05/29 03:15:01 bradleym Exp $
----------------------------------------------------------------------------
0. Disclaimer

2
Documentation/input/joystick-api.txt
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@ -5,8 +5,6 @@
7 Aug 1998
$Id: joystick-api.txt,v 1.2 2001/05/08 21:21:23 vojtech Exp $
1. Initialization
~~~~~~~~~~~~~~~~~

1
Documentation/input/joystick-parport.txt
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@ -2,7 +2,6 @@
(c) 1998-2000 Vojtech Pavlik <vojtech@ucw.cz>
(c) 1998 Andree Borrmann <a.borrmann@tu-bs.de>
Sponsored by SuSE
$Id: joystick-parport.txt,v 1.6 2001/09/25 09:31:32 vojtech Exp $
----------------------------------------------------------------------------
0. Disclaimer

1
Documentation/input/joystick.txt
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@ -1,7 +1,6 @@
Linux Joystick driver v2.0.0
(c) 1996-2000 Vojtech Pavlik <vojtech@ucw.cz>
Sponsored by SuSE
$Id: joystick.txt,v 1.12 2002/03/03 12:13:07 jdeneux Exp $
----------------------------------------------------------------------------
0. Disclaimer

1
Documentation/ioctl-number.txt
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@ -117,6 +117,7 @@ Code Seq# Include File Comments
<mailto:natalia@nikhefk.nikhef.nl>
'c' 00-7F linux/comstats.h conflict!
'c' 00-7F linux/coda.h conflict!
'c' 80-9F asm-s390/chsc.h
'd' 00-FF linux/char/drm/drm/h conflict!
'd' 00-DF linux/video_decoder.h conflict!
'd' F0-FF linux/digi1.h

7
Documentation/ioctl/hdio.txt
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@ -508,12 +508,13 @@ HDIO_DRIVE_RESET execute a device reset
error returns:
EACCES Access denied: requires CAP_SYS_ADMIN
ENXIO No such device: phy dead or ctl_addr == 0
EIO I/O error: reset timed out or hardware error
notes:
Abort any current command, prevent anything else from being
queued, execute a reset on the device, and issue BLKRRPART
ioctl on the block device.
Execute a reset on the device as soon as the current IO
operation has completed.
Executes an ATAPI soft reset if applicable, otherwise
executes an ATA soft reset on the controller.

2
Documentation/kdump/kdump.txt
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@ -109,7 +109,7 @@ There are two possible methods of using Kdump.
2) Or use the system kernel binary itself as dump-capture kernel and there is
no need to build a separate dump-capture kernel. This is possible
only with the architecutres which support a relocatable kernel. As
of today i386 and ia64 architectures support relocatable kernel.
of today, i386, x86_64 and ia64 architectures support relocatable kernel.
Building a relocatable kernel is advantageous from the point of view that
one does not have to build a second kernel for capturing the dump. But

81
Documentation/kernel-parameters.txt
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@ -147,10 +147,14 @@ and is between 256 and 4096 characters. It is defined in the file
default: 0
acpi_sleep= [HW,ACPI] Sleep options
Format: { s3_bios, s3_mode, s3_beep }
Format: { s3_bios, s3_mode, s3_beep, old_ordering }
See Documentation/power/video.txt for s3_bios and s3_mode.
s3_beep is for debugging; it makes the PC's speaker beep
as soon as the kernel's real-mode entry point is called.
old_ordering causes the ACPI 1.0 ordering of the _PTS
control method, wrt putting devices into low power
states, to be enforced (the ACPI 2.0 ordering of _PTS is
used by default).
acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
Format: { level | edge | high | low }
@ -271,6 +275,17 @@ and is between 256 and 4096 characters. It is defined in the file
aic79xx= [HW,SCSI]
See Documentation/scsi/aic79xx.txt.
amd_iommu= [HW,X86-84]
Pass parameters to the AMD IOMMU driver in the system.
Possible values are:
isolate - enable device isolation (each device, as far
as possible, will get its own protection
domain)
amd_iommu_size= [HW,X86-64]
Define the size of the aperture for the AMD IOMMU
driver. Possible values are:
'32M', '64M' (default), '128M', '256M', '512M', '1G'
amijoy.map= [HW,JOY] Amiga joystick support
Map of devices attached to JOY0DAT and JOY1DAT
Format: <a>,<b>
@ -560,6 +575,8 @@ and is between 256 and 4096 characters. It is defined in the file
debug_objects [KNL] Enable object debugging
debugpat [X86] Enable PAT debugging
decnet.addr= [HW,NET]
Format: <area>[,<node>]
See also Documentation/networking/decnet.txt.
@ -599,6 +616,29 @@ and is between 256 and 4096 characters. It is defined in the file
See drivers/char/README.epca and
Documentation/digiepca.txt.
disable_mtrr_cleanup [X86]
enable_mtrr_cleanup [X86]
The kernel tries to adjust MTRR layout from continuous
to discrete, to make X server driver able to add WB
entry later. This parameter enables/disables that.
mtrr_chunk_size=nn[KMG] [X86]
used for mtrr cleanup. It is largest continous chunk
that could hold holes aka. UC entries.
mtrr_gran_size=nn[KMG] [X86]
Used for mtrr cleanup. It is granularity of mtrr block.
Default is 1.
Large value could prevent small alignment from
using up MTRRs.
mtrr_spare_reg_nr=n [X86]
Format: <integer>
Range: 0,7 : spare reg number
Default : 1
Used for mtrr cleanup. It is spare mtrr entries number.
Set to 2 or more if your graphical card needs more.
disable_mtrr_trim [X86, Intel and AMD only]
By default the kernel will trim any uncacheable
memory out of your available memory pool based on
@ -722,9 +762,6 @@ and is between 256 and 4096 characters. It is defined in the file
hd= [EIDE] (E)IDE hard drive subsystem geometry
Format: <cyl>,<head>,<sect>
hd?= [HW] (E)IDE subsystem
hd?lun= See Documentation/ide/ide.txt.
highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
size of <nn>. This works even on boxes that have no
highmem otherwise. This also works to reduce highmem
@ -785,7 +822,7 @@ and is between 256 and 4096 characters. It is defined in the file
See Documentation/ide/ide.txt.
idle= [X86]
Format: idle=poll or idle=mwait
Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
Poll forces a polling idle loop that can slightly improves the performance
of waking up a idle CPU, but will use a lot of power and make the system
run hot. Not recommended.
@ -793,6 +830,9 @@ and is between 256 and 4096 characters. It is defined in the file
to not use it because it doesn't save as much power as a normal idle
loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
as idle=poll.
idle=halt. Halt is forced to be used for CPU idle.
In such case C2/C3 won't be used again.
idle=nomwait. Disable mwait for CPU C-states
ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
Claim all unknown PCI IDE storage controllers.
@ -1166,7 +1206,7 @@ and is between 256 and 4096 characters. It is defined in the file
or
memmap=0x10000$0x18690000
memtest= [KNL,X86_64] Enable memtest
memtest= [KNL,X86] Enable memtest
Format: <integer>
range: 0,4 : pattern number
default : 0 <disable>
@ -1208,6 +1248,11 @@ and is between 256 and 4096 characters. It is defined in the file
mtdparts= [MTD]
See drivers/mtd/cmdlinepart.c.
mtdset= [ARM]
ARM/S3C2412 JIVE boot control
See arch/arm/mach-s3c2412/mach-jive.c
mtouchusb.raw_coordinates=
[HW] Make the MicroTouch USB driver use raw coordinates
('y', default) or cooked coordinates ('n')
@ -1234,6 +1279,13 @@ and is between 256 and 4096 characters. It is defined in the file
This usage is only documented in each driver source
file if at all.
nf_conntrack.acct=
[NETFILTER] Enable connection tracking flow accounting
0 to disable accounting
1 to enable accounting
Default value depends on CONFIG_NF_CT_ACCT that is
going to be removed in 2.6.29.
nfsaddrs= [NFS]
See Documentation/filesystems/nfsroot.txt.
@ -1496,6 +1548,9 @@ and is between 256 and 4096 characters. It is defined in the file
Use with caution as certain devices share
address decoders between ROMs and other
resources.
norom [X86-32,X86_64] Do not assign address space to
expansion ROMs that do not already have
BIOS assigned address ranges.
irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
assigned automatically to PCI devices. You can
make the kernel exclude IRQs of your ISA cards
@ -1571,6 +1626,10 @@ and is between 256 and 4096 characters. It is defined in the file
Format: { parport<nr> | timid | 0 }
See also Documentation/parport.txt.
pmtmr= [X86] Manual setup of pmtmr I/O Port.
Override pmtimer IOPort with a hex value.
e.g. pmtmr=0x508
pnpacpi= [ACPI]
{ off }
@ -1975,6 +2034,9 @@ and is between 256 and 4096 characters. It is defined in the file
snd-ymfpci= [HW,ALSA]
softlockup_panic=
[KNL] Should the soft-lockup detector generate panics.
sonypi.*= [HW] Sony Programmable I/O Control Device driver
See Documentation/sonypi.txt
@ -2106,6 +2168,10 @@ and is between 256 and 4096 characters. It is defined in the file
Note that genuine overcurrent events won't be
reported either.
unknown_nmi_panic
[X86-32,X86-64]
Set unknown_nmi_panic=1 early on boot.
usbcore.autosuspend=
[USB] The autosuspend time delay (in seconds) used
for newly-detected USB devices (default 2). This
@ -2116,6 +2182,9 @@ and is between 256 and 4096 characters. It is defined in the file
usbhid.mousepoll=
[USBHID] The interval which mice are to be polled at.
add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
kernel's map of available physical RAM.
vdso= [X86-32,SH,x86-64]
vdso=2: enable compat VDSO (default with COMPAT_VDSO)
vdso=1: enable VDSO (default)

1
Documentation/kprobes.txt
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@ -172,6 +172,7 @@ architectures:
- ia64 (Does not support probes on instruction slot1.)
- sparc64 (Return probes not yet implemented.)
- arm
- ppc
3. Configuring Kprobes

2
Documentation/laptops/acer-wmi.txt
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@ -174,8 +174,6 @@ The LED is exposed through the LED subsystem, and can be found in:
The mail LED is autodetected, so if you don't have one, the LED device won't
be registered.
If you have a mail LED that is not green, please report this to me.
Backlight
*********

30
Documentation/md.txt
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@ -236,6 +236,11 @@ All md devices contain:
writing the word for the desired state, however some states
cannot be explicitly set, and some transitions are not allowed.
Select/poll works on this file. All changes except between
active_idle and active (which can be frequent and are not
very interesting) are notified. active->active_idle is
reported if the metadata is externally managed.
clear
No devices, no size, no level
Writing is equivalent to STOP_ARRAY ioctl
@ -292,6 +297,10 @@ Each directory contains:
writemostly - device will only be subject to read
requests if there are no other options.
This applies only to raid1 arrays.
blocked - device has failed, metadata is "external",
and the failure hasn't been acknowledged yet.
Writes that would write to this device if
it were not faulty are blocked.
spare - device is working, but not a full member.
This includes spares that are in the process
of being recovered to
@ -301,6 +310,12 @@ Each directory contains:
Writing "remove" removes the device from the array.
Writing "writemostly" sets the writemostly flag.
Writing "-writemostly" clears the writemostly flag.
Writing "blocked" sets the "blocked" flag.
Writing "-blocked" clear the "blocked" flag and allows writes
to complete.
This file responds to select/poll. Any change to 'faulty'
or 'blocked' causes an event.
errors
An approximate count of read errors that have been detected on
@ -332,7 +347,7 @@ Each directory contains:
for storage of data. This will normally be the same as the
component_size. This can be written while assembling an
array. If a value less than the current component_size is
written, component_size will be reduced to this value.
written, it will be rejected.
An active md device will also contain and entry for each active device
@ -381,6 +396,19 @@ also have
'check' and 'repair' will start the appropriate process
providing the current state is 'idle'.
This file responds to select/poll. Any important change in the value
triggers a poll event. Sometimes the value will briefly be
"recover" if a recovery seems to be needed, but cannot be
achieved. In that case, the transition to "recover" isn't
notified, but the transition away is.
degraded
This contains a count of the number of devices by which the
arrays is degraded. So an optimal array with show '0'. A
single failed/missing drive will show '1', etc.
This file responds to select/poll, any increase or decrease
in the count of missing devices will trigger an event.
mismatch_count
When performing 'check' and 'repair', and possibly when
performing 'resync', md will count the number of errors that are

100
Documentation/networking/bonding.txt
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@ -289,35 +289,73 @@ downdelay
fail_over_mac
Specifies whether active-backup mode should set all slaves to
the same MAC address (the traditional behavior), or, when
enabled, change the bond's MAC address when changing the
active interface (i.e., fail over the MAC address itself).
the same MAC address at enslavement (the traditional
behavior), or, when enabled, perform special handling of the
bond's MAC address in accordance with the selected policy.
Fail over MAC is useful for devices that cannot ever alter
their MAC address, or for devices that refuse incoming
broadcasts with their own source MAC (which interferes with
the ARP monitor).
Possible values are:
The down side of fail over MAC is that every device on the
network must be updated via gratuitous ARP, vs. just updating
a switch or set of switches (which often takes place for any
traffic, not just ARP traffic, if the switch snoops incoming
traffic to update its tables) for the traditional method. If
the gratuitous ARP is lost, communication may be disrupted.
none or 0
When fail over MAC is used in conjuction with the mii monitor,
devices which assert link up prior to being able to actually
transmit and receive are particularly susecptible to loss of
the gratuitous ARP, and an appropriate updelay setting may be
required.
This setting disables fail_over_mac, and causes
bonding to set all slaves of an active-backup bond to
the same MAC address at enslavement time. This is the
default.
A value of 0 disables fail over MAC, and is the default. A
value of 1 enables fail over MAC. This option is enabled
automatically if the first slave added cannot change its MAC
address. This option may be modified via sysfs only when no
slaves are present in the bond.
active or 1
This option was added in bonding version 3.2.0.
The "active" fail_over_mac policy indicates that the
MAC address of the bond should always be the MAC
address of the currently active slave. The MAC
address of the slaves is not changed; instead, the MAC
address of the bond changes during a failover.
This policy is useful for devices that cannot ever
alter their MAC address, or for devices that refuse
incoming broadcasts with their own source MAC (which
interferes with the ARP monitor).
The down side of this policy is that every device on
the network must be updated via gratuitous ARP,
vs. just updating a switch or set of switches (which
often takes place for any traffic, not just ARP
traffic, if the switch snoops incoming traffic to
update its tables) for the traditional method. If the
gratuitous ARP is lost, communication may be
disrupted.
When this policy is used in conjuction with the mii
monitor, devices which assert link up prior to being
able to actually transmit and receive are particularly
susecptible to loss of the gratuitous ARP, and an
appropriate updelay setting may be required.
follow or 2
The "follow" fail_over_mac policy causes the MAC
address of the bond to be selected normally (normally
the MAC address of the first slave added to the bond).
However, the second and subsequent slaves are not set
to this MAC address while they are in a backup role; a
slave is programmed with the bond's MAC address at
failover time (and the formerly active slave receives
the newly active slave's MAC address).
This policy is useful for multiport devices that
either become confused or incur a performance penalty
when multiple ports are programmed with the same MAC
address.
The default policy is none, unless the first slave cannot
change its MAC address, in which case the active policy is
selected by default.
This option may be modified via sysfs only when no slaves are
present in the bond.
This option was added in bonding version 3.2.0. The "follow"
policy was added in bonding version 3.3.0.
lacp_rate
@ -338,7 +376,8 @@ max_bonds
Specifies the number of bonding devices to create for this
instance of the bonding driver. E.g., if max_bonds is 3, and
the bonding driver is not already loaded, then bond0, bond1
and bond2 will be created. The default value is 1.
and bond2 will be created. The default value is 1. Specifying
a value of 0 will load bonding, but will not create any devices.
miimon
@ -501,6 +540,17 @@ mode
swapped with the new curr_active_slave that was
chosen.
num_grat_arp
Specifies the number of gratuitous ARPs to be issued after a
failover event. One gratuitous ARP is issued immediately after
the failover, subsequent ARPs are sent at a rate of one per link
monitor interval (arp_interval or miimon, whichever is active).
The valid range is 0 - 255; the default value is 1. This option
affects only the active-backup mode. This option was added for
bonding version 3.3.0.
primary
A string (eth0, eth2, etc) specifying which slave is the

167
Documentation/networking/dm9000.txt Normal file
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@ -0,0 +1,167 @@
DM9000 Network driver
=====================
Copyright 2008 Simtec Electronics,
Ben Dooks <ben@simtec.co.uk> <ben-linux@fluff.org>
Introduction
------------
This file describes how to use the DM9000 platform-device based network driver
that is contained in the files drivers/net/dm9000.c and drivers/net/dm9000.h.
The driver supports three DM9000 variants, the DM9000E which is the first chip
supported as well as the newer DM9000A and DM9000B devices. It is currently
maintained and tested by Ben Dooks, who should be CC: to any patches for this
driver.
Defining the platform device
----------------------------
The minimum set of resources attached to the platform device are as follows:
1) The physical address of the address register
2) The physical address of the data register
3) The IRQ line the device's interrupt pin is connected to.
These resources should be specified in that order, as the ordering of the
two address regions is important (the driver expects these to be address
and then data).
An example from arch/arm/mach-s3c2410/mach-bast.c is:
static struct resource bast_dm9k_resource[] = {
[0] = {
.start = S3C2410_CS5 + BAST_PA_DM9000,
.end = S3C2410_CS5 + BAST_PA_DM9000 + 3,
.flags = IORESOURCE_MEM,
},
[1] = {
.start = S3C2410_CS5 + BAST_PA_DM9000 + 0x40,
.end = S3C2410_CS5 + BAST_PA_DM9000 + 0x40 + 0x3f,
.flags = IORESOURCE_MEM,
},
[2] = {
.start = IRQ_DM9000,
.end = IRQ_DM9000,
.flags = IORESOURCE_IRQ | IORESOURCE_IRQ_HIGHLEVEL,
}
};
static struct platform_device bast_device_dm9k = {
.name = "dm9000",
.id = 0,
.num_resources = ARRAY_SIZE(bast_dm9k_resource),
.resource = bast_dm9k_resource,
};
Note the setting of the IRQ trigger flag in bast_dm9k_resource[2].flags,
as this will generate a warning if it is not present. The trigger from
the flags field will be passed to request_irq() when registering the IRQ
handler to ensure that the IRQ is setup correctly.
This shows a typical platform device, without the optional configuration
platform data supplied. The next example uses the same resources, but adds
the optional platform data to pass extra configuration data:
static struct dm9000_plat_data bast_dm9k_platdata = {
.flags = DM9000_PLATF_16BITONLY,
};
static struct platform_device bast_device_dm9k = {
.name = "dm9000",
.id = 0,
.num_resources = ARRAY_SIZE(bast_dm9k_resource),
.resource = bast_dm9k_resource,
.dev = {
.platform_data = &bast_dm9k_platdata,
}
};
The platform data is defined in include/linux/dm9000.h and described below.
Platform data
-------------
Extra platform data for the DM9000 can describe the IO bus width to the
device, whether or not an external PHY is attached to the device and
the availability of an external configuration EEPROM.
The flags for the platform data .flags field are as follows:
DM9000_PLATF_8BITONLY
The IO should be done with 8bit operations.
DM9000_PLATF_16BITONLY
The IO should be done with 16bit operations.
DM9000_PLATF_32BITONLY
The IO should be done with 32bit operations.
DM9000_PLATF_EXT_PHY
The chip is connected to an external PHY.
DM9000_PLATF_NO_EEPROM
This can be used to signify that the board does not have an
EEPROM, or that the EEPROM should be hidden from the user.
DM9000_PLATF_SIMPLE_PHY
Switch to using the simpler PHY polling method which does not
try and read the MII PHY state regularly. This is only available
when using the internal PHY. See the section on link state polling
for more information.
The config symbol DM9000_FORCE_SIMPLE_PHY_POLL, Kconfig entry
"Force simple NSR based PHY polling" allows this flag to be
forced on at build time.
PHY Link state polling
----------------------
The driver keeps track of the link state and informs the network core
about link (carrier) availablilty. This is managed by several methods
depending on the version of the chip and on which PHY is being used.
For the internal PHY, the original (and currently default) method is
to read the MII state, either when the status changes if we have the
necessary interrupt support in the chip or every two seconds via a
periodic timer.
To reduce the overhead for the internal PHY, there is now the option
of using the DM9000_FORCE_SIMPLE_PHY_POLL config, or DM9000_PLATF_SIMPLE_PHY
platform data option to read the summary information without the
expensive MII accesses. This method is faster, but does not print
as much information.
When using an external PHY, the driver currently has to poll the MII
link status as there is no method for getting an interrupt on link change.
DM9000A / DM9000B
-----------------
These chips are functionally similar to the DM9000E and are supported easily
by the same driver. The features are:
1) Interrupt on internal PHY state change. This means that the periodic
polling of the PHY status may be disabled on these devices when using
the internal PHY.
2) TCP/UDP checksum offloading, which the driver does not currently support.
ethtool
-------
The driver supports the ethtool interface for access to the driver
state information, the PHY state and the EEPROM.

14
Documentation/networking/e1000.txt
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@ -513,21 +513,11 @@ Additional Configurations
Intel(R) PRO/1000 PT Dual Port Server Connection
Intel(R) PRO/1000 PT Dual Port Server Adapter
Intel(R) PRO/1000 PF Dual Port Server Adapter
Intel(R) PRO/1000 PT Quad Port Server Adapter
Intel(R) PRO/1000 PT Quad Port Server Adapter
NAPI
----
NAPI (Rx polling mode) is supported in the e1000 driver. NAPI is enabled
or disabled based on the configuration of the kernel. To override
the default, use the following compile-time flags.
To enable NAPI, compile the driver module, passing in a configuration option:
make CFLAGS_EXTRA=-DE1000_NAPI install
To disable NAPI, compile the driver module, passing in a configuration option:
make CFLAGS_EXTRA=-DE1000_NO_NAPI install
NAPI (Rx polling mode) is enabled in the e1000 driver.
See www.cyberus.ca/~hadi/usenix-paper.tgz for more information on NAPI.

21
Documentation/networking/ip-sysctl.txt
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@ -551,8 +551,9 @@ icmp_echo_ignore_broadcasts - BOOLEAN
icmp_ratelimit - INTEGER
Limit the maximal rates for sending ICMP packets whose type matches
icmp_ratemask (see below) to specific targets.
0 to disable any limiting, otherwise the maximal rate in jiffies(1)
Default: 100
0 to disable any limiting,
otherwise the minimal space between responses in milliseconds.
Default: 1000
icmp_ratemask - INTEGER
Mask made of ICMP types for which rates are being limited.
@ -1023,11 +1024,23 @@ max_addresses - INTEGER
autoconfigured addresses.
Default: 16
disable_ipv6 - BOOLEAN
Disable IPv6 operation.
Default: FALSE (enable IPv6 operation)
accept_dad - INTEGER
Whether to accept DAD (Duplicate Address Detection).
0: Disable DAD
1: Enable DAD (default)
2: Enable DAD, and disable IPv6 operation if MAC-based duplicate
link-local address has been found.
icmp/*:
ratelimit - INTEGER
Limit the maximal rates for sending ICMPv6 packets.
0 to disable any limiting, otherwise the maximal rate in jiffies(1)
Default: 100
0 to disable any limiting,
otherwise the minimal space between responses in milliseconds.
Default: 1000
IPv6 Update by:

419
Documentation/networking/ixgb.txt
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@ -1,7 +1,7 @@
Linux* Base Driver for the Intel(R) PRO/10GbE Family of Adapters
================================================================
Linux Base Driver for 10 Gigabit Intel(R) Network Connection
=============================================================
November 17, 2004
October 9, 2007
Contents
@ -9,94 +9,151 @@ Contents
- In This Release
- Identifying Your Adapter
- Building and Installation
- Command Line Parameters
- Improving Performance
- Additional Configurations
- Known Issues/Troubleshooting
- Support
In This Release
===============
This file describes the Linux* Base Driver for the Intel(R) PRO/10GbE Family
of Adapters, version 1.0.x.
This file describes the ixgb Linux Base Driver for the 10 Gigabit Intel(R)
Network Connection. This driver includes support for Itanium(R)2-based
systems.
For questions related to hardware requirements, refer to the documentation
supplied with your 10 Gigabit adapter. All hardware requirements listed apply
to use with Linux.
The following features are available in this kernel:
- Native VLANs
- Channel Bonding (teaming)
- SNMP
Channel Bonding documentation can be found in the Linux kernel source:
/Documentation/networking/bonding.txt
The driver information previously displayed in the /proc filesystem is not
supported in this release. Alternatively, you can use ethtool (version 1.6
or later), lspci, and ifconfig to obtain the same information.
Instructions on updating ethtool can be found in the section "Additional
Configurations" later in this document.
For questions related to hardware requirements, refer to the documentation
supplied with your Intel PRO/10GbE adapter. All hardware requirements listed
apply to use with Linux.
Identifying Your Adapter
========================
To verify your Intel adapter is supported, find the board ID number on the
adapter. Look for a label that has a barcode and a number in the format
A12345-001.
The following Intel network adapters are compatible with the drivers in this
release:
Use the above information and the Adapter & Driver ID Guide at:
Controller Adapter Name Physical Layer
---------- ------------ --------------
82597EX Intel(R) PRO/10GbE LR/SR/CX4 10G Base-LR (1310 nm optical fiber)
Server Adapters 10G Base-SR (850 nm optical fiber)
10G Base-CX4(twin-axial copper cabling)
http://support.intel.com/support/network/adapter/pro100/21397.htm
For more information on how to identify your adapter, go to the Adapter &
Driver ID Guide at:
For the latest Intel network drivers for Linux, go to:
http://support.intel.com/support/network/sb/CS-012904.htm
Building and Installation
=========================
select m for "Intel(R) PRO/10GbE support" located at:
Location:
-> Device Drivers
-> Network device support (NETDEVICES [=y])
-> Ethernet (10000 Mbit) (NETDEV_10000 [=y])
1. make modules && make modules_install
2. Load the module:
    modprobe ixgb <parameter>=<value>
The insmod command can be used if the full
path to the driver module is specified. For example:
insmod /lib/modules/<KERNEL VERSION>/kernel/drivers/net/ixgb/ixgb.ko
With 2.6 based kernels also make sure that older ixgb drivers are
removed from the kernel, before loading the new module:
rmmod ixgb; modprobe ixgb
3. Assign an IP address to the interface by entering the following, where
x is the interface number:
ifconfig ethx <IP_address>
4. Verify that the interface works. Enter the following, where <IP_address>
is the IP address for another machine on the same subnet as the interface
that is being tested:
ping <IP_address>
http://downloadfinder.intel.com/scripts-df/support_intel.asp
Command Line Parameters
=======================
If the driver is built as a module, the following optional parameters are
used by entering them on the command line with the modprobe or insmod command
using this syntax:
If the driver is built as a module, the following optional parameters are
used by entering them on the command line with the modprobe command using
this syntax:
modprobe ixgb [<option>=<VAL1>,<VAL2>,...]
insmod ixgb [<option>=<VAL1>,<VAL2>,...]
For example, with two 10GbE PCI adapters, entering:
For example, with two PRO/10GbE PCI adapters, entering:
modprobe ixgb TxDescriptors=80,128
insmod ixgb TxDescriptors=80,128
loads the ixgb driver with 80 TX resources for the first adapter and 128 TX
loads the ixgb driver with 80 TX resources for the first adapter and 128 TX
resources for the second adapter.
The default value for each parameter is generally the recommended setting,
unless otherwise noted. Also, if the driver is statically built into the
kernel, the driver is loaded with the default values for all the parameters.
Ethtool can be used to change some of the parameters at runtime.
unless otherwise noted.
FlowControl
Valid Range: 0-3 (0=none, 1=Rx only, 2=Tx only, 3=Rx&Tx)
Default: Read from the EEPROM
If EEPROM is not detected, default is 3
This parameter controls the automatic generation(Tx) and response(Rx) to
Ethernet PAUSE frames.
If EEPROM is not detected, default is 1
This parameter controls the automatic generation(Tx) and response(Rx) to
Ethernet PAUSE frames. There are hardware bugs associated with enabling
Tx flow control so beware.
RxDescriptors
Valid Range: 64-512
Default Value: 512
This value is the number of receive descriptors allocated by the driver.
Increasing this value allows the driver to buffer more incoming packets.
Each descriptor is 16 bytes. A receive buffer is also allocated for
each descriptor and can be either 2048, 4056, 8192, or 16384 bytes,
depending on the MTU setting. When the MTU size is 1500 or less, the
This value is the number of receive descriptors allocated by the driver.
Increasing this value allows the driver to buffer more incoming packets.
Each descriptor is 16 bytes. A receive buffer is also allocated for
each descriptor and can be either 2048, 4056, 8192, or 16384 bytes,
depending on the MTU setting. When the MTU size is 1500 or less, the
receive buffer size is 2048 bytes. When the MTU is greater than 1500 the
receive buffer size will be either 4056, 8192, or 16384 bytes. The
receive buffer size will be either 4056, 8192, or 16384 bytes. The
maximum MTU size is 16114.
RxIntDelay
Valid Range: 0-65535 (0=off)
Default Value: 6
This value delays the generation of receive interrupts in units of
0.8192 microseconds. Receive interrupt reduction can improve CPU
efficiency if properly tuned for specific network traffic. Increasing
this value adds extra latency to frame reception and can end up
decreasing the throughput of TCP traffic. If the system is reporting
dropped receives, this value may be set too high, causing the driver to
Default Value: 72
This value delays the generation of receive interrupts in units of
0.8192 microseconds. Receive interrupt reduction can improve CPU
efficiency if properly tuned for specific network traffic. Increasing
this value adds extra latency to frame reception and can end up
decreasing the throughput of TCP traffic. If the system is reporting
dropped receives, this value may be set too high, causing the driver to
run out of available receive descriptors.
TxDescriptors
Valid Range: 64-4096
Default Value: 256
This value is the number of transmit descriptors allocated by the driver.
Increasing this value allows the driver to queue more transmits. Each
Increasing this value allows the driver to queue more transmits. Each
descriptor is 16 bytes.
XsumRX
@ -105,51 +162,49 @@ Default Value: 1
A value of '1' indicates that the driver should enable IP checksum
offload for received packets (both UDP and TCP) to the adapter hardware.
XsumTX
Valid Range: 0-1
Default Value: 1
A value of '1' indicates that the driver should enable IP checksum
offload for transmitted packets (both UDP and TCP) to the adapter
hardware.
Improving Performance
=====================
With the Intel PRO/10 GbE adapter, the default Linux configuration will very
likely limit the total available throughput artificially. There is a set of
things that when applied together increase the ability of Linux to transmit
and receive data. The following enhancements were originally acquired from
settings published at http://www.spec.org/web99 for various submitted results
using Linux.
With the 10 Gigabit server adapters, the default Linux configuration will
very likely limit the total available throughput artificially. There is a set
of configuration changes that, when applied together, will increase the ability
of Linux to transmit and receive data. The following enhancements were
originally acquired from settings published at http://www.spec.org/web99/ for
various submitted results using Linux.
NOTE: These changes are only suggestions, and serve as a starting point for
tuning your network performance.
NOTE: These changes are only suggestions, and serve as a starting point for
tuning your network performance.
The changes are made in three major ways, listed in order of greatest effect:
- Use ifconfig to modify the mtu (maximum transmission unit) and the txqueuelen
- Use ifconfig to modify the mtu (maximum transmission unit) and the txqueuelen
parameter.
- Use sysctl to modify /proc parameters (essentially kernel tuning)
- Use setpci to modify the MMRBC field in PCI-X configuration space to increase
- Use setpci to modify the MMRBC field in PCI-X configuration space to increase
transmit burst lengths on the bus.
NOTE: setpci modifies the adapter's configuration registers to allow it to read
up to 4k bytes at a time (for transmits). However, for some systems the
behavior after modifying this register may be undefined (possibly errors of some
kind). A power-cycle, hard reset or explicitly setting the e6 register back to
22 (setpci -d 8086:1048 e6.b=22) may be required to get back to a stable
configuration.
NOTE: setpci modifies the adapter's configuration registers to allow it to read
up to 4k bytes at a time (for transmits). However, for some systems the
behavior after modifying this register may be undefined (possibly errors of
some kind). A power-cycle, hard reset or explicitly setting the e6 register
back to 22 (setpci -d 8086:1a48 e6.b=22) may be required to get back to a
stable configuration.
- COPY these lines and paste them into ixgb_perf.sh:
#!/bin/bash
echo "configuring network performance , edit this file to change the interface"
echo "configuring network performance , edit this file to change the interface
or device ID of 10GbE card"
# set mmrbc to 4k reads, modify only Intel 10GbE device IDs
setpci -d 8086:1048 e6.b=2e
# set the MTU (max transmission unit) - it requires your switch and clients to change too!
# replace 1a48 with appropriate 10GbE device's ID installed on the system,
# if needed.
setpci -d 8086:1a48 e6.b=2e
# set the MTU (max transmission unit) - it requires your switch and clients
# to change as well.
# set the txqueuelen
# your ixgb adapter should be loaded as eth1 for this to work, change if needed
ifconfig eth1 mtu 9000 txqueuelen 1000 up
# call the sysctl utility to modify /proc/sys entries
sysctl -p ./sysctl_ixgb.conf
# call the sysctl utility to modify /proc/sys entries
sysctl -p ./sysctl_ixgb.conf
- END ixgb_perf.sh
- COPY these lines and paste them into sysctl_ixgb.conf:
@ -159,54 +214,220 @@ sysctl -p ./sysctl_ixgb.conf
# several network benchmark tests, your mileage may vary
### IPV4 specific settings
net.ipv4.tcp_timestamps = 0 # turns TCP timestamp support off, default 1, reduces CPU use
net.ipv4.tcp_sack = 0 # turn SACK support off, default on
# on systems with a VERY fast bus -> memory interface this is the big gainer
net.ipv4.tcp_rmem = 10000000 10000000 10000000 # sets min/default/max TCP read buffer, default 4096 87380 174760
net.ipv4.tcp_wmem = 10000000 10000000 10000000 # sets min/pressure/max TCP write buffer, default 4096 16384 131072
net.ipv4.tcp_mem = 10000000 10000000 10000000 # sets min/pressure/max TCP buffer space, default 31744 32256 32768
# turn TCP timestamp support off, default 1, reduces CPU use
net.ipv4.tcp_timestamps = 0
# turn SACK support off, default on
# on systems with a VERY fast bus -> memory interface this is the big gainer
net.ipv4.tcp_sack = 0
# set min/default/max TCP read buffer, default 4096 87380 174760
net.ipv4.tcp_rmem = 10000000 10000000 10000000
# set min/pressure/max TCP write buffer, default 4096 16384 131072
net.ipv4.tcp_wmem = 10000000 10000000 10000000
# set min/pressure/max TCP buffer space, default 31744 32256 32768
net.ipv4.tcp_mem = 10000000 10000000 10000000
### CORE settings (mostly for socket and UDP effect)
net.core.rmem_max = 524287 # maximum receive socket buffer size, default 131071
net.core.wmem_max = 524287 # maximum send socket buffer size, default 131071
net.core.rmem_default = 524287 # default receive socket buffer size, default 65535
net.core.wmem_default = 524287 # default send socket buffer size, default 65535
net.core.optmem_max = 524287 # maximum amount of option memory buffers, default 10240
net.core.netdev_max_backlog = 300000 # number of unprocessed input packets before kernel starts dropping them, default 300
# set maximum receive socket buffer size, default 131071
net.core.rmem_max = 524287
# set maximum send socket buffer size, default 131071
net.core.wmem_max = 524287
# set default receive socket buffer size, default 65535
net.core.rmem_default = 524287
# set default send socket buffer size, default 65535
net.core.wmem_default = 524287
# set maximum amount of option memory buffers, default 10240
net.core.optmem_max = 524287
# set number of unprocessed input packets before kernel starts dropping them; default 300
net.core.netdev_max_backlog = 300000
- END sysctl_ixgb.conf
Edit the ixgb_perf.sh script if necessary to change eth1 to whatever interface
your ixgb driver is using.
Edit the ixgb_perf.sh script if necessary to change eth1 to whatever interface
your ixgb driver is using and/or replace '1a48' with appropriate 10GbE device's
ID installed on the system.
NOTE: Unless these scripts are added to the boot process, these changes will
only last only until the next system reboot.
NOTE: Unless these scripts are added to the boot process, these changes will
only last only until the next system reboot.
Resolving Slow UDP Traffic
--------------------------
If your server does not seem to be able to receive UDP traffic as fast as it
can receive TCP traffic, it could be because Linux, by default, does not set
the network stack buffers as large as they need to be to support high UDP
transfer rates. One way to alleviate this problem is to allow more memory to
be used by the IP stack to store incoming data.
If your server does not seem to be able to receive UDP traffic as fast as it
can receive TCP traffic, it could be because Linux, by default, does not set
the network stack buffers as large as they need to be to support high UDP
transfer rates. One way to alleviate this problem is to allow more memory to
be used by the IP stack to store incoming data.
For instance, use the commands:
For instance, use the commands:
sysctl -w net.core.rmem_max=262143
and
sysctl -w net.core.rmem_default=262143
to increase the read buffer memory max and default to 262143 (256k - 1) from
defaults of max=131071 (128k - 1) and default=65535 (64k - 1). These variables
will increase the amount of memory used by the network stack for receives, and
to increase the read buffer memory max and default to 262143 (256k - 1) from
defaults of max=131071 (128k - 1) and default=65535 (64k - 1). These variables
will increase the amount of memory used by the network stack for receives, and
can be increased significantly more if necessary for your application.
Additional Configurations
=========================
Configuring the Driver on Different Distributions
-------------------------------------------------
Configuring a network driver to load properly when the system is started is
distribution dependent. Typically, the configuration process involves adding
an alias line to /etc/modprobe.conf as well as editing other system startup
scripts and/or configuration files. Many popular Linux distributions ship
with tools to make these changes for you. To learn the proper way to
configure a network device for your system, refer to your distribution
documentation. If during this process you are asked for the driver or module
name, the name for the Linux Base Driver for the Intel 10GbE Family of
Adapters is ixgb.
Viewing Link Messages
---------------------
Link messages will not be displayed to the console if the distribution is
restricting system messages. In order to see network driver link messages on
your console, set dmesg to eight by entering the following:
dmesg -n 8
NOTE: This setting is not saved across reboots.
Jumbo Frames
------------
The driver supports Jumbo Frames for all adapters. Jumbo Frames support is
enabled by changing the MTU to a value larger than the default of 1500.
The maximum value for the MTU is 16114. Use the ifconfig command to
increase the MTU size. For example:
ifconfig ethx mtu 9000 up
The maximum MTU setting for Jumbo Frames is 16114. This value coincides
with the maximum Jumbo Frames size of 16128.
Ethtool
-------
The driver utilizes the ethtool interface for driver configuration and
diagnostics, as well as displaying statistical information. Ethtool
version 1.6 or later is required for this functionality.
The latest release of ethtool can be found from
http://sourceforge.net/projects/gkernel
NOTE: Ethtool 1.6 only supports a limited set of ethtool options. Support
for a more complete ethtool feature set can be enabled by upgrading
to the latest version.
NAPI
----
NAPI (Rx polling mode) is supported in the ixgb driver. NAPI is enabled
or disabled based on the configuration of the kernel. see CONFIG_IXGB_NAPI
See www.cyberus.ca/~hadi/usenix-paper.tgz for more information on NAPI.
Known Issues/Troubleshooting
============================
NOTE: After installing the driver, if your Intel Network Connection is not
working, verify in the "In This Release" section of the readme that you have
installed the correct driver.
Intel(R) PRO/10GbE CX4 Server Adapter Cable Interoperability Issue with
Fujitsu XENPAK Module in SmartBits Chassis
---------------------------------------------------------------------
Excessive CRC errors may be observed if the Intel(R) PRO/10GbE CX4
Server adapter is connected to a Fujitsu XENPAK CX4 module in a SmartBits
chassis using 15 m/24AWG cable assemblies manufactured by Fujitsu or Leoni.
The CRC errors may be received either by the Intel(R) PRO/10GbE CX4
Server adapter or the SmartBits. If this situation occurs using a different
cable assembly may resolve the issue.
CX4 Server Adapter Cable Interoperability Issues with HP Procurve 3400cl
Switch Port
------------------------------------------------------------------------
Excessive CRC errors may be observed if the Intel(R) PRO/10GbE CX4 Server
adapter is connected to an HP Procurve 3400cl switch port using short cables
(1 m or shorter). If this situation occurs, using a longer cable may resolve
the issue.
Excessive CRC errors may be observed using Fujitsu 24AWG cable assemblies that
Are 10 m or longer or where using a Leoni 15 m/24AWG cable assembly. The CRC
errors may be received either by the CX4 Server adapter or at the switch. If
this situation occurs, using a different cable assembly may resolve the issue.
Jumbo Frames System Requirement
-------------------------------
Memory allocation failures have been observed on Linux systems with 64 MB
of RAM or less that are running Jumbo Frames. If you are using Jumbo
Frames, your system may require more than the advertised minimum
requirement of 64 MB of system memory.
Performance Degradation with Jumbo Frames
-----------------------------------------
Degradation in throughput performance may be observed in some Jumbo frames
environments. If this is observed, increasing the application's socket buffer
size and/or increasing the /proc/sys/net/ipv4/tcp_*mem entry values may help.
See the specific application manual and /usr/src/linux*/Documentation/
networking/ip-sysctl.txt for more details.
Allocating Rx Buffers when Using Jumbo Frames
---------------------------------------------
Allocating Rx buffers when using Jumbo Frames on 2.6.x kernels may fail if
the available memory is heavily fragmented. This issue may be seen with PCI-X
adapters or with packet split disabled. This can be reduced or eliminated
by changing the amount of available memory for receive buffer allocation, by
increasing /proc/sys/vm/min_free_kbytes.
Multiple Interfaces on Same Ethernet Broadcast Network
------------------------------------------------------
Due to the default ARP behavior on Linux, it is not possible to have
one system on two IP networks in the same Ethernet broadcast domain
(non-partitioned switch) behave as expected. All Ethernet interfaces
will respond to IP traffic for any IP address assigned to the system.
This results in unbalanced receive traffic.
If you have multiple interfaces in a server, do either of the following:
- Turn on ARP filtering by entering:
echo 1 > /proc/sys/net/ipv4/conf/all/arp_filter
- Install the interfaces in separate broadcast domains - either in
different switches or in a switch partitioned to VLANs.
UDP Stress Test Dropped Packet Issue
--------------------------------------
Under small packets UDP stress test with 10GbE driver, the Linux system
may drop UDP packets due to the fullness of socket buffers. You may want
to change the driver's Flow Control variables to the minimum value for
controlling packet reception.
Tx Hangs Possible Under Stress
------------------------------
Under stress conditions, if TX hangs occur, turning off TSO
"ethtool -K eth0 tso off" may resolve the problem.
Support
=======
For general information and support, go to the Intel support website at:
For general information, go to the Intel support website at:
http://support.intel.com
or the Intel Wired Networking project hosted by Sourceforge at:
http://sourceforge.net/projects/e1000
If an issue is identified with the released source code on the supported
kernel with a supported adapter, email the specific information related to
the issue to linux.nics@intel.com.
kernel with a supported adapter, email the specific information related
to the issue to e1000-devel@lists.sf.net

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@ -0,0 +1,67 @@
mac80211_hwsim - software simulator of 802.11 radio(s) for mac80211
Copyright (c) 2008, Jouni Malinen <j@w1.fi>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License version 2 as
published by the Free Software Foundation.
Introduction
mac80211_hwsim is a Linux kernel module that can be used to simulate
arbitrary number of IEEE 802.11 radios for mac80211. It can be used to
test most of the mac80211 functionality and user space tools (e.g.,
hostapd and wpa_supplicant) in a way that matches very closely with
the normal case of using real WLAN hardware. From the mac80211 view
point, mac80211_hwsim is yet another hardware driver, i.e., no changes
to mac80211 are needed to use this testing tool.
The main goal for mac80211_hwsim is to make it easier for developers
to test their code and work with new features to mac80211, hostapd,
and wpa_supplicant. The simulated radios do not have the limitations
of real hardware, so it is easy to generate an arbitrary test setup
and always reproduce the same setup for future tests. In addition,
since all radio operation is simulated, any channel can be used in
tests regardless of regulatory rules.
mac80211_hwsim kernel module has a parameter 'radios' that can be used
to select how many radios are simulated (default 2). This allows
configuration of both very simply setups (e.g., just a single access
point and a station) or large scale tests (multiple access points with
hundreds of stations).
mac80211_hwsim works by tracking the current channel of each virtual
radio and copying all transmitted frames to all other radios that are
currently enabled and on the same channel as the transmitting
radio. Software encryption in mac80211 is used so that the frames are
actually encrypted over the virtual air interface to allow more
complete testing of encryption.
A global monitoring netdev, hwsim#, is created independent of
mac80211. This interface can be used to monitor all transmitted frames
regardless of channel.
Simple example
This example shows how to use mac80211_hwsim to simulate two radios:
one to act as an access point and the other as a station that
associates with the AP. hostapd and wpa_supplicant are used to take
care of WPA2-PSK authentication. In addition, hostapd is also
processing access point side of association.
Please note that the current Linux kernel does not enable AP mode, so a
simple patch is needed to enable AP mode selection:
http://johannes.sipsolutions.net/patches/kernel/all/LATEST/006-allow-ap-vlan-modes.patch
# Build mac80211_hwsim as part of kernel configuration
# Load the module
modprobe mac80211_hwsim
# Run hostapd (AP) for wlan0
hostapd hostapd.conf
# Run wpa_supplicant (station) for wlan1
wpa_supplicant -Dwext -iwlan1 -c wpa_supplicant.conf

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@ -0,0 +1,11 @@
interface=wlan0
driver=nl80211
hw_mode=g
channel=1
ssid=mac80211 test
wpa=2
wpa_key_mgmt=WPA-PSK
wpa_pairwise=CCMP
wpa_passphrase=12345678

10
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@ -0,0 +1,10 @@
ctrl_interface=/var/run/wpa_supplicant
network={
ssid="mac80211 test"
psk="12345678"
key_mgmt=WPA-PSK
proto=WPA2
pairwise=CCMP
group=CCMP
}

90
Documentation/networking/multiqueue.txt
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@ -3,19 +3,11 @@
===========================================
Section 1: Base driver requirements for implementing multiqueue support
Section 2: Qdisc support for multiqueue devices
Section 3: Brief howto using PRIO or RR for multiqueue devices
Intro: Kernel support for multiqueue devices
---------------------------------------------------------
Kernel support for multiqueue devices is only an API that is presented to the
netdevice layer for base drivers to implement. This feature is part of the
core networking stack, and all network devices will be running on the
multiqueue-aware stack. If a base driver only has one queue, then these
changes are transparent to that driver.
Kernel support for multiqueue devices is always present.
Section 1: Base driver requirements for implementing multiqueue support
-----------------------------------------------------------------------
@ -32,84 +24,4 @@ netif_{start|stop|wake}_subqueue() functions to manage each queue while the
device is still operational. netdev->queue_lock is still used when the device
comes online or when it's completely shut down (unregister_netdev(), etc.).
Finally, the base driver should indicate that it is a multiqueue device. The
feature flag NETIF_F_MULTI_QUEUE should be added to the netdev->features
bitmap on device initialization. Below is an example from e1000:
#ifdef CONFIG_E1000_MQ
if ( (adapter->hw.mac.type == e1000_82571) ||
(adapter->hw.mac.type == e1000_82572) ||
(adapter->hw.mac.type == e1000_80003es2lan))
netdev->features |= NETIF_F_MULTI_QUEUE;
#endif
Section 2: Qdisc support for multiqueue devices
-----------------------------------------------
Currently two qdiscs support multiqueue devices. A new round-robin qdisc,
sch_rr, and sch_prio. The qdisc is responsible for classifying the skb's to
bands and queues, and will store the queue mapping into skb->queue_mapping.
Use this field in the base driver to determine which queue to send the skb
to.
sch_rr has been added for hardware that doesn't want scheduling policies from
software, so it's a straight round-robin qdisc. It uses the same syntax and
classification priomap that sch_prio uses, so it should be intuitive to
configure for people who've used sch_prio.
In order to utilitize the multiqueue features of the qdiscs, the network
device layer needs to enable multiple queue support. This can be done by
selecting NETDEVICES_MULTIQUEUE under Drivers.
The PRIO qdisc naturally plugs into a multiqueue device. If
NETDEVICES_MULTIQUEUE is selected, then on qdisc load, the number of
bands requested is compared to the number of queues on the hardware. If they
are equal, it sets a one-to-one mapping up between the queues and bands. If
they're not equal, it will not load the qdisc. This is the same behavior
for RR. Once the association is made, any skb that is classified will have
skb->queue_mapping set, which will allow the driver to properly queue skb's
to multiple queues.
Section 3: Brief howto using PRIO and RR for multiqueue devices
---------------------------------------------------------------
The userspace command 'tc,' part of the iproute2 package, is used to configure
qdiscs. To add the PRIO qdisc to your network device, assuming the device is
called eth0, run the following command:
# tc qdisc add dev eth0 root handle 1: prio bands 4 multiqueue
This will create 4 bands, 0 being highest priority, and associate those bands
to the queues on your NIC. Assuming eth0 has 4 Tx queues, the band mapping
would look like:
band 0 => queue 0
band 1 => queue 1
band 2 => queue 2
band 3 => queue 3
Traffic will begin flowing through each queue if your TOS values are assigning
traffic across the various bands. For example, ssh traffic will always try to
go out band 0 based on TOS -> Linux priority conversion (realtime traffic),
so it will be sent out queue 0. ICMP traffic (pings) fall into the "normal"
traffic classification, which is band 1. Therefore pings will be send out
queue 1 on the NIC.
Note the use of the multiqueue keyword. This is only in versions of iproute2
that support multiqueue networking devices; if this is omitted when loading
a qdisc onto a multiqueue device, the qdisc will load and operate the same
if it were loaded onto a single-queue device (i.e. - sends all traffic to
queue 0).
Another alternative to multiqueue band allocation can be done by using the
multiqueue option and specify 0 bands. If this is the case, the qdisc will
allocate the number of bands to equal the number of queues that the device
reports, and bring the qdisc online.
The behavior of tc filters remains the same, where it will override TOS priority
classification.
Author: Peter P. Waskiewicz Jr. <peter.p.waskiewicz.jr@intel.com>

7
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@ -52,13 +52,10 @@ d. MSI/MSI-X. Can be enabled on platforms which support this feature
(IA64, Xeon) resulting in noticeable performance improvement(upto 7%
on certain platforms).
e. NAPI. Compile-time option(CONFIG_S2IO_NAPI) for better Rx interrupt
moderation.
f. Statistics. Comprehensive MAC-level and software statistics displayed
e. Statistics. Comprehensive MAC-level and software statistics displayed
using "ethtool -S" option.
g. Multi-FIFO/Ring. Supports up to 8 transmit queues and receive rings,
f. Multi-FIFO/Ring. Supports up to 8 transmit queues and receive rings,
with multiple steering options.
4. Command line parameters

2
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@ -148,7 +148,7 @@
getsockopt(sockfd, SOL_SOCKET, SO_NO_CHECK, &value, ...);
is meaningless (as in TCP). Packets with a zero checksum field are
illegal (cf. RFC 3828, sec. 3.1) will be silently discarded.
illegal (cf. RFC 3828, sec. 3.1) and will be silently discarded.
4) Fragmentation

16
Documentation/nmi_watchdog.txt
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@ -10,7 +10,7 @@ us to generate 'watchdog NMI interrupts'. (NMI: Non Maskable Interrupt
which get executed even if the system is otherwise locked up hard).
This can be used to debug hard kernel lockups. By executing periodic
NMI interrupts, the kernel can monitor whether any CPU has locked up,
and print out debugging messages if so.
and print out debugging messages if so.
In order to use the NMI watchdog, you need to have APIC support in your
kernel. For SMP kernels, APIC support gets compiled in automatically. For
@ -22,8 +22,7 @@ CONFIG_X86_UP_IOAPIC is for uniprocessor with an IO-APIC. [Note: certain
kernel debugging options, such as Kernel Stack Meter or Kernel Tracer,
may implicitly disable the NMI watchdog.]
For x86-64, the needed APIC is always compiled in, and the NMI watchdog is
always enabled with I/O-APIC mode (nmi_watchdog=1).
For x86-64, the needed APIC is always compiled in.
Using local APIC (nmi_watchdog=2) needs the first performance register, so
you can't use it for other purposes (such as high precision performance
@ -63,16 +62,15 @@ when the system is idle), but if your system locks up on anything but the
"hlt", then you are out of luck -- the event will not happen at all and the
watchdog won't trigger. This is a shortcoming of the local APIC watchdog
-- unfortunately there is no "clock ticks" event that would work all the
time. The I/O APIC watchdog is driven externally and has no such shortcoming.
time. The I/O APIC watchdog is driven externally and has no such shortcoming.
But its NMI frequency is much higher, resulting in a more significant hit
to the overall system performance.
NOTE: starting with 2.4.2-ac18 the NMI-oopser is disabled by default,
you have to enable it with a boot time parameter. Prior to 2.4.2-ac18
the NMI-oopser is enabled unconditionally on x86 SMP boxes.
On x86 nmi_watchdog is disabled by default so you have to enable it with
a boot time parameter.
On x86-64 the NMI oopser is on by default. On 64bit Intel CPUs
it uses IO-APIC by default and on AMD it uses local APIC.
NOTE: In kernels prior to 2.4.2-ac18 the NMI-oopser is enabled unconditionally
on x86 SMP boxes.
[ feel free to send bug reports, suggestions and patches to
Ingo Molnar <mingo@redhat.com> or the Linux SMP mailing

1235
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The PowerPC boot wrapper
------------------------
Copyright (C) Secret Lab Technologies Ltd.
PowerPC image targets compresses and wraps the kernel image (vmlinux) with
a boot wrapper to make it usable by the system firmware. There is no
standard PowerPC firmware interface, so the boot wrapper is designed to
be adaptable for each kind of image that needs to be built.
The boot wrapper can be found in the arch/powerpc/boot/ directory. The
Makefile in that directory has targets for all the available image types.
The different image types are used to support all of the various firmware
interfaces found on PowerPC platforms. OpenFirmware is the most commonly
used firmware type on general purpose PowerPC systems from Apple, IBM and
others. U-Boot is typically found on embedded PowerPC hardware, but there
are a handful of other firmware implementations which are also popular. Each
firmware interface requires a different image format.
The boot wrapper is built from the makefile in arch/powerpc/boot/Makefile and
it uses the wrapper script (arch/powerpc/boot/wrapper) to generate target
image. The details of the build system is discussed in the next section.
Currently, the following image format targets exist:
cuImage.%: Backwards compatible uImage for older version of
U-Boot (for versions that don't understand the device
tree). This image embeds a device tree blob inside
the image. The boot wrapper, kernel and device tree
are all embedded inside the U-Boot uImage file format
with boot wrapper code that extracts data from the old
bd_info structure and loads the data into the device
tree before jumping into the kernel.
Because of the series of #ifdefs found in the
bd_info structure used in the old U-Boot interfaces,
cuImages are platform specific. Each specific
U-Boot platform has a different platform init file
which populates the embedded device tree with data
from the platform specific bd_info file. The platform
specific cuImage platform init code can be found in
arch/powerpc/boot/cuboot.*.c. Selection of the correct
cuImage init code for a specific board can be found in
the wrapper structure.
dtbImage.%: Similar to zImage, except device tree blob is embedded
inside the image instead of provided by firmware. The
output image file can be either an elf file or a flat
binary depending on the platform.
dtbImages are used on systems which do not have an
interface for passing a device tree directly.
dtbImages are similar to simpleImages except that
dtbImages have platform specific code for extracting
data from the board firmware, but simpleImages do not
talk to the firmware at all.
PlayStation 3 support uses dtbImage. So do Embedded
Planet boards using the PlanetCore firmware. Board
specific initialization code is typically found in a
file named arch/powerpc/boot/<platform>.c; but this
can be overridden by the wrapper script.
simpleImage.%: Firmware independent compressed image that does not
depend on any particular firmware interface and embeds
a device tree blob. This image is a flat binary that
can be loaded to any location in RAM and jumped to.
Firmware cannot pass any configuration data to the
kernel with this image type and it depends entirely on
the embedded device tree for all information.
The simpleImage is useful for booting systems with
an unknown firmware interface or for booting from
a debugger when no firmware is present (such as on
the Xilinx Virtex platform). The only assumption that
simpleImage makes is that RAM is correctly initialized
and that the MMU is either off or has RAM mapped to
base address 0.
simpleImage also supports inserting special platform
specific initialization code to the start of the bootup
sequence. The virtex405 platform uses this feature to
ensure that the cache is invalidated before caching
is enabled. Platform specific initialization code is
added as part of the wrapper script and is keyed on
the image target name. For example, all
simpleImage.virtex405-* targets will add the
virtex405-head.S initialization code (This also means
that the dts file for virtex405 targets should be
named (virtex405-<board>.dts). Search the wrapper
script for 'virtex405' and see the file
arch/powerpc/boot/virtex405-head.S for details.
treeImage.%; Image format for used with OpenBIOS firmware found
on some ppc4xx hardware. This image embeds a device
tree blob inside the image.
uImage: Native image format used by U-Boot. The uImage target
does not add any boot code. It just wraps a compressed
vmlinux in the uImage data structure. This image
requires a version of U-Boot that is able to pass
a device tree to the kernel at boot. If using an older
version of U-Boot, then you need to use a cuImage
instead.
zImage.%: Image format which does not embed a device tree.
Used by OpenFirmware and other firmware interfaces
which are able to supply a device tree. This image
expects firmware to provide the device tree at boot.
Typically, if you have general purpose PowerPC
hardware then you want this image format.
Image types which embed a device tree blob (simpleImage, dtbImage, treeImage,
and cuImage) all generate the device tree blob from a file in the
arch/powerpc/boot/dts/ directory. The Makefile selects the correct device
tree source based on the name of the target. Therefore, if the kernel is
built with 'make treeImage.walnut simpleImage.virtex405-ml403', then the
build system will use arch/powerpc/boot/dts/walnut.dts to build
treeImage.walnut and arch/powerpc/boot/dts/virtex405-ml403.dts to build
the simpleImage.virtex405-ml403.
Two special targets called 'zImage' and 'zImage.initrd' also exist. These
targets build all the default images as selected by the kernel configuration.
Default images are selected by the boot wrapper Makefile
(arch/powerpc/boot/Makefile) by adding targets to the $image-y variable. Look
at the Makefile to see which default image targets are available.
How it is built
---------------
arch/powerpc is designed to support multiplatform kernels, which means
that a single vmlinux image can be booted on many different target boards.
It also means that the boot wrapper must be able to wrap for many kinds of
images on a single build. The design decision was made to not use any
conditional compilation code (#ifdef, etc) in the boot wrapper source code.
All of the boot wrapper pieces are buildable at any time regardless of the
kernel configuration. Building all the wrapper bits on every kernel build
also ensures that obscure parts of the wrapper are at the very least compile
tested in a large variety of environments.
The wrapper is adapted for different image types at link time by linking in
just the wrapper bits that are appropriate for the image type. The 'wrapper
script' (found in arch/powerpc/boot/wrapper) is called by the Makefile and
is responsible for selecting the correct wrapper bits for the image type.
The arguments are well documented in the script's comment block, so they
are not repeated here. However, it is worth mentioning that the script
uses the -p (platform) argument as the main method of deciding which wrapper
bits to compile in. Look for the large 'case "$platform" in' block in the
middle of the script. This is also the place where platform specific fixups
can be selected by changing the link order.
In particular, care should be taken when working with cuImages. cuImage
wrapper bits are very board specific and care should be taken to make sure
the target you are trying to build is supported by the wrapper bits.

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* Board Control and Status (BCSR)
Required properties:
- device_type : Should be "board-control"
- reg : Offset and length of the register set for the device
Example:
bcsr@f8000000 {
device_type = "board-control";
reg = <f8000000 8000>;
};
* Freescale on board FPGA
This is the memory-mapped registers for on board FPGA.
Required properities:
- compatible : should be "fsl,fpga-pixis".
- reg : should contain the address and the lenght of the FPPGA register
set.
Example (MPC8610HPCD):
board-control@e8000000 {
compatible = "fsl,fpga-pixis";
reg = <0xe8000000 32>;
};

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@ -0,0 +1,67 @@
* Freescale Communications Processor Module
NOTE: This is an interim binding, and will likely change slightly,
as more devices are supported. The QE bindings especially are
incomplete.
* Root CPM node
Properties:
- compatible : "fsl,cpm1", "fsl,cpm2", or "fsl,qe".
- reg : A 48-byte region beginning with CPCR.
Example:
cpm@119c0 {
#address-cells = <1>;
#size-cells = <1>;
#interrupt-cells = <2>;
compatible = "fsl,mpc8272-cpm", "fsl,cpm2";
reg = <119c0 30>;
}
* Properties common to mulitple CPM/QE devices
- fsl,cpm-command : This value is ORed with the opcode and command flag
to specify the device on which a CPM command operates.
- fsl,cpm-brg : Indicates which baud rate generator the device
is associated with. If absent, an unused BRG
should be dynamically allocated. If zero, the
device uses an external clock rather than a BRG.
- reg : Unless otherwise specified, the first resource represents the
scc/fcc/ucc registers, and the second represents the device's
parameter RAM region (if it has one).
* Multi-User RAM (MURAM)
The multi-user/dual-ported RAM is expressed as a bus under the CPM node.
Ranges must be set up subject to the following restrictions:
- Children's reg nodes must be offsets from the start of all muram, even
if the user-data area does not begin at zero.
- If multiple range entries are used, the difference between the parent
address and the child address must be the same in all, so that a single
mapping can cover them all while maintaining the ability to determine
CPM-side offsets with pointer subtraction. It is recommended that
multiple range entries not be used.
- A child address of zero must be translatable, even if no reg resources
contain it.
A child "data" node must exist, compatible with "fsl,cpm-muram-data", to
indicate the portion of muram that is usable by the OS for arbitrary
purposes. The data node may have an arbitrary number of reg resources,
all of which contribute to the allocatable muram pool.
Example, based on mpc8272:
muram@0 {
#address-cells = <1>;
#size-cells = <1>;
ranges = <0 0 10000>;
data@0 {
compatible = "fsl,cpm-muram-data";
reg = <0 2000 9800 800>;
};
};

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@ -0,0 +1,21 @@
* Baud Rate Generators
Currently defined compatibles:
fsl,cpm-brg
fsl,cpm1-brg
fsl,cpm2-brg
Properties:
- reg : There may be an arbitrary number of reg resources; BRG
numbers are assigned to these in order.
- clock-frequency : Specifies the base frequency driving
the BRG.
Example:
brg@119f0 {
compatible = "fsl,mpc8272-brg",
"fsl,cpm2-brg",
"fsl,cpm-brg";
reg = <119f0 10 115f0 10>;
clock-frequency = <d#25000000>;
};

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@ -0,0 +1,41 @@
* I2C
The I2C controller is expressed as a bus under the CPM node.
Properties:
- compatible : "fsl,cpm1-i2c", "fsl,cpm2-i2c"
- reg : On CPM2 devices, the second resource doesn't specify the I2C
Parameter RAM itself, but the I2C_BASE field of the CPM2 Parameter RAM
(typically 0x8afc 0x2).
- #address-cells : Should be one. The cell is the i2c device address with
the r/w bit set to zero.
- #size-cells : Should be zero.
- clock-frequency : Can be used to set the i2c clock frequency. If
unspecified, a default frequency of 60kHz is being used.
The following two properties are deprecated. They are only used by legacy
i2c drivers to find the bus to probe:
- linux,i2c-index : Can be used to hard code an i2c bus number. By default,
the bus number is dynamically assigned by the i2c core.
- linux,i2c-class : Can be used to override the i2c class. The class is used
by legacy i2c device drivers to find a bus in a specific context like
system management, video or sound. By default, I2C_CLASS_HWMON (1) is
being used. The definition of the classes can be found in
include/i2c/i2c.h
Example, based on mpc823:
i2c@860 {
compatible = "fsl,mpc823-i2c",
"fsl,cpm1-i2c";
reg = <0x860 0x20 0x3c80 0x30>;
interrupts = <16>;
interrupt-parent = <&CPM_PIC>;
fsl,cpm-command = <0x10>;
#address-cells = <1>;
#size-cells = <0>;
rtc@68 {
compatible = "dallas,ds1307";
reg = <0x68>;
};
};

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@ -0,0 +1,18 @@
* Interrupt Controllers
Currently defined compatibles:
- fsl,cpm1-pic
- only one interrupt cell
- fsl,pq1-pic
- fsl,cpm2-pic
- second interrupt cell is level/sense:
- 2 is falling edge
- 8 is active low
Example:
interrupt-controller@10c00 {
#interrupt-cells = <2>;
interrupt-controller;
reg = <10c00 80>;
compatible = "mpc8272-pic", "fsl,cpm2-pic";
};

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@ -0,0 +1,15 @@
* USB (Universal Serial Bus Controller)
Properties:
- compatible : "fsl,cpm1-usb", "fsl,cpm2-usb", "fsl,qe-usb"
Example:
usb@11bc0 {
#address-cells = <1>;
#size-cells = <0>;
compatible = "fsl,cpm2-usb";
reg = <11b60 18 8b00 100>;
interrupts = <b 8>;
interrupt-parent = <&PIC>;
fsl,cpm-command = <2e600000>;
};

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@ -0,0 +1,38 @@
Every GPIO controller node must have #gpio-cells property defined,
this information will be used to translate gpio-specifiers.
On CPM1 devices, all ports are using slightly different register layouts.
Ports A, C and D are 16bit ports and Ports B and E are 32bit ports.
On CPM2 devices, all ports are 32bit ports and use a common register layout.
Required properties:
- compatible : "fsl,cpm1-pario-bank-a", "fsl,cpm1-pario-bank-b",
"fsl,cpm1-pario-bank-c", "fsl,cpm1-pario-bank-d",
"fsl,cpm1-pario-bank-e", "fsl,cpm2-pario-bank"
- #gpio-cells : Should be two. The first cell is the pin number and the
second cell is used to specify optional paramters (currently unused).
- gpio-controller : Marks the port as GPIO controller.
Example of three SOC GPIO banks defined as gpio-controller nodes:
CPM1_PIO_A: gpio-controller@950 {
#gpio-cells = <2>;
compatible = "fsl,cpm1-pario-bank-a";
reg = <0x950 0x10>;
gpio-controller;
};
CPM1_PIO_B: gpio-controller@ab8 {
#gpio-cells = <2>;
compatible = "fsl,cpm1-pario-bank-b";
reg = <0xab8 0x10>;
gpio-controller;
};
CPM1_PIO_E: gpio-controller@ac8 {
#gpio-cells = <2>;
compatible = "fsl,cpm1-pario-bank-e";
reg = <0xac8 0x18>;
gpio-controller;
};

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@ -0,0 +1,45 @@
* Network
Currently defined compatibles:
- fsl,cpm1-scc-enet
- fsl,cpm2-scc-enet
- fsl,cpm1-fec-enet
- fsl,cpm2-fcc-enet (third resource is GFEMR)
- fsl,qe-enet
Example:
ethernet@11300 {
device_type = "network";
compatible = "fsl,mpc8272-fcc-enet",
"fsl,cpm2-fcc-enet";
reg = <11300 20 8400 100 11390 1>;
local-mac-address = [ 00 00 00 00 00 00 ];
interrupts = <20 8>;
interrupt-parent = <&PIC>;
phy-handle = <&PHY0>;
fsl,cpm-command = <12000300>;
};
* MDIO
Currently defined compatibles:
fsl,pq1-fec-mdio (reg is same as first resource of FEC device)
fsl,cpm2-mdio-bitbang (reg is port C registers)
Properties for fsl,cpm2-mdio-bitbang:
fsl,mdio-pin : pin of port C controlling mdio data
fsl,mdc-pin : pin of port C controlling mdio clock
Example:
mdio@10d40 {
device_type = "mdio";
compatible = "fsl,mpc8272ads-mdio-bitbang",
"fsl,mpc8272-mdio-bitbang",
"fsl,cpm2-mdio-bitbang";
reg = <10d40 14>;
#address-cells = <1>;
#size-cells = <0>;
fsl,mdio-pin = <12>;
fsl,mdc-pin = <13>;
};

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* Freescale QUICC Engine module (QE)
This represents qe module that is installed on PowerQUICC II Pro.
NOTE: This is an interim binding; it should be updated to fit
in with the CPM binding later in this document.
Basically, it is a bus of devices, that could act more or less
as a complete entity (UCC, USB etc ). All of them should be siblings on
the "root" qe node, using the common properties from there.
The description below applies to the qe of MPC8360 and
more nodes and properties would be extended in the future.
i) Root QE device
Required properties:
- compatible : should be "fsl,qe";
- model : precise model of the QE, Can be "QE", "CPM", or "CPM2"
- reg : offset and length of the device registers.
- bus-frequency : the clock frequency for QUICC Engine.
Recommended properties
- brg-frequency : the internal clock source frequency for baud-rate
generators in Hz.
Example:
qe@e0100000 {
#address-cells = <1>;
#size-cells = <1>;
#interrupt-cells = <2>;
compatible = "fsl,qe";
ranges = <0 e0100000 00100000>;
reg = <e0100000 480>;
brg-frequency = <0>;
bus-frequency = <179A7B00>;
}
* Multi-User RAM (MURAM)
Required properties:
- compatible : should be "fsl,qe-muram", "fsl,cpm-muram".
- mode : the could be "host" or "slave".
- ranges : Should be defined as specified in 1) to describe the
translation of MURAM addresses.
- data-only : sub-node which defines the address area under MURAM
bus that can be allocated as data/parameter
Example:
muram@10000 {
compatible = "fsl,qe-muram", "fsl,cpm-muram";
ranges = <0 00010000 0000c000>;
data-only@0{
compatible = "fsl,qe-muram-data",
"fsl,cpm-muram-data";
reg = <0 c000>;
};
};

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* Uploaded QE firmware
If a new firwmare has been uploaded to the QE (usually by the
boot loader), then a 'firmware' child node should be added to the QE
node. This node provides information on the uploaded firmware that
device drivers may need.
Required properties:
- id: The string name of the firmware. This is taken from the 'id'
member of the qe_firmware structure of the uploaded firmware.
Device drivers can search this string to determine if the
firmware they want is already present.
- extended-modes: The Extended Modes bitfield, taken from the
firmware binary. It is a 64-bit number represented
as an array of two 32-bit numbers.
- virtual-traps: The virtual traps, taken from the firmware binary.
It is an array of 8 32-bit numbers.
Example:
firmware {
id = "Soft-UART";
extended-modes = <0 0>;
virtual-traps = <0 0 0 0 0 0 0 0>;
};

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* Parallel I/O Ports
This node configures Parallel I/O ports for CPUs with QE support.
The node should reside in the "soc" node of the tree. For each
device that using parallel I/O ports, a child node should be created.
See the definition of the Pin configuration nodes below for more
information.
Required properties:
- device_type : should be "par_io".
- reg : offset to the register set and its length.
- num-ports : number of Parallel I/O ports
Example:
par_io@1400 {
reg = <1400 100>;
#address-cells = <1>;
#size-cells = <0>;
device_type = "par_io";
num-ports = <7>;
ucc_pin@01 {
......
};
Note that "par_io" nodes are obsolete, and should not be used for
the new device trees. Instead, each Par I/O bank should be represented
via its own gpio-controller node:
Required properties:
- #gpio-cells : should be "2".
- compatible : should be "fsl,<chip>-qe-pario-bank",
"fsl,mpc8323-qe-pario-bank".
- reg : offset to the register set and its length.
- gpio-controller : node to identify gpio controllers.
Example:
qe_pio_a: gpio-controller@1400 {
#gpio-cells = <2>;
compatible = "fsl,mpc8360-qe-pario-bank",
"fsl,mpc8323-qe-pario-bank";
reg = <0x1400 0x18>;
gpio-controller;
};
qe_pio_e: gpio-controller@1460 {
#gpio-cells = <2>;
compatible = "fsl,mpc8360-qe-pario-bank",
"fsl,mpc8323-qe-pario-bank";
reg = <0x1460 0x18>;
gpio-controller;
};

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* Pin configuration nodes
Required properties:
- linux,phandle : phandle of this node; likely referenced by a QE
device.
- pio-map : array of pin configurations. Each pin is defined by 6
integers. The six numbers are respectively: port, pin, dir,
open_drain, assignment, has_irq.
- port : port number of the pin; 0-6 represent port A-G in UM.
- pin : pin number in the port.
- dir : direction of the pin, should encode as follows:
0 = The pin is disabled
1 = The pin is an output
2 = The pin is an input
3 = The pin is I/O
- open_drain : indicates the pin is normal or wired-OR:
0 = The pin is actively driven as an output
1 = The pin is an open-drain driver. As an output, the pin is
driven active-low, otherwise it is three-stated.
- assignment : function number of the pin according to the Pin Assignment
tables in User Manual. Each pin can have up to 4 possible functions in
QE and two options for CPM.
- has_irq : indicates if the pin is used as source of external
interrupts.
Example:
ucc_pin@01 {
linux,phandle = <140001>;
pio-map = <
/* port pin dir open_drain assignment has_irq */
0 3 1 0 1 0 /* TxD0 */
0 4 1 0 1 0 /* TxD1 */
0 5 1 0 1 0 /* TxD2 */
0 6 1 0 1 0 /* TxD3 */
1 6 1 0 3 0 /* TxD4 */
1 7 1 0 1 0 /* TxD5 */
1 9 1 0 2 0 /* TxD6 */
1 a 1 0 2 0 /* TxD7 */
0 9 2 0 1 0 /* RxD0 */
0 a 2 0 1 0 /* RxD1 */
0 b 2 0 1 0 /* RxD2 */
0 c 2 0 1 0 /* RxD3 */
0 d 2 0 1 0 /* RxD4 */
1 1 2 0 2 0 /* RxD5 */
1 0 2 0 2 0 /* RxD6 */
1 4 2 0 2 0 /* RxD7 */
0 7 1 0 1 0 /* TX_EN */
0 8 1 0 1 0 /* TX_ER */
0 f 2 0 1 0 /* RX_DV */
0 10 2 0 1 0 /* RX_ER */
0 0 2 0 1 0 /* RX_CLK */
2 9 1 0 3 0 /* GTX_CLK - CLK10 */
2 8 2 0 1 0>; /* GTX125 - CLK9 */
};

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* UCC (Unified Communications Controllers)
Required properties:
- device_type : should be "network", "hldc", "uart", "transparent"
"bisync", "atm", or "serial".
- compatible : could be "ucc_geth" or "fsl_atm" and so on.
- cell-index : the ucc number(1-8), corresponding to UCCx in UM.
- reg : Offset and length of the register set for the device
- interrupts : <a b> where a is the interrupt number and b is a
field that represents an encoding of the sense and level
information for the interrupt. This should be encoded based on
the information in section 2) depending on the type of interrupt
controller you have.
- interrupt-parent : the phandle for the interrupt controller that
services interrupts for this device.
- pio-handle : The phandle for the Parallel I/O port configuration.
- port-number : for UART drivers, the port number to use, between 0 and 3.
This usually corresponds to the /dev/ttyQE device, e.g. <0> = /dev/ttyQE0.
The port number is added to the minor number of the device. Unlike the
CPM UART driver, the port-number is required for the QE UART driver.
- soft-uart : for UART drivers, if specified this means the QE UART device
driver should use "Soft-UART" mode, which is needed on some SOCs that have
broken UART hardware. Soft-UART is provided via a microcode upload.
- rx-clock-name: the UCC receive clock source
"none": clock source is disabled
"brg1" through "brg16": clock source is BRG1-BRG16, respectively
"clk1" through "clk24": clock source is CLK1-CLK24, respectively
- tx-clock-name: the UCC transmit clock source
"none": clock source is disabled
"brg1" through "brg16": clock source is BRG1-BRG16, respectively
"clk1" through "clk24": clock source is CLK1-CLK24, respectively
The following two properties are deprecated. rx-clock has been replaced
with rx-clock-name, and tx-clock has been replaced with tx-clock-name.
Drivers that currently use the deprecated properties should continue to
do so, in order to support older device trees, but they should be updated
to check for the new properties first.
- rx-clock : represents the UCC receive clock source.
0x00 : clock source is disabled;
0x1~0x10 : clock source is BRG1~BRG16 respectively;
0x11~0x28: clock source is QE_CLK1~QE_CLK24 respectively.
- tx-clock: represents the UCC transmit clock source;
0x00 : clock source is disabled;
0x1~0x10 : clock source is BRG1~BRG16 respectively;
0x11~0x28: clock source is QE_CLK1~QE_CLK24 respectively.
Required properties for network device_type:
- mac-address : list of bytes representing the ethernet address.
- phy-handle : The phandle for the PHY connected to this controller.
Recommended properties:
- phy-connection-type : a string naming the controller/PHY interface type,
i.e., "mii" (default), "rmii", "gmii", "rgmii", "rgmii-id" (Internal
Delay), "rgmii-txid" (delay on TX only), "rgmii-rxid" (delay on RX only),
"tbi", or "rtbi".
Example:
ucc@2000 {
device_type = "network";
compatible = "ucc_geth";
cell-index = <1>;
reg = <2000 200>;
interrupts = <a0 0>;
interrupt-parent = <700>;
mac-address = [ 00 04 9f 00 23 23 ];
rx-clock = "none";
tx-clock = "clk9";
phy-handle = <212000>;
phy-connection-type = "gmii";
pio-handle = <140001>;
};

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Freescale QUICC Engine USB Controller
Required properties:
- compatible : should be "fsl,<chip>-qe-usb", "fsl,mpc8323-qe-usb".
- reg : the first two cells should contain usb registers location and
length, the next two two cells should contain PRAM location and
length.
- interrupts : should contain USB interrupt.
- interrupt-parent : interrupt source phandle.
- fsl,fullspeed-clock : specifies the full speed USB clock source:
"none": clock source is disabled
"brg1" through "brg16": clock source is BRG1-BRG16, respectively
"clk1" through "clk24": clock source is CLK1-CLK24, respectively
- fsl,lowspeed-clock : specifies the low speed USB clock source:
"none": clock source is disabled
"brg1" through "brg16": clock source is BRG1-BRG16, respectively
"clk1" through "clk24": clock source is CLK1-CLK24, respectively
- hub-power-budget : USB power budget for the root hub, in mA.
- gpios : should specify GPIOs in this order: USBOE, USBTP, USBTN, USBRP,
USBRN, SPEED (optional), and POWER (optional).
Example:
usb@6c0 {
compatible = "fsl,mpc8360-qe-usb", "fsl,mpc8323-qe-usb";
reg = <0x6c0 0x40 0x8b00 0x100>;
interrupts = <11>;
interrupt-parent = <&qeic>;
fsl,fullspeed-clock = "clk21";
gpios = <&qe_pio_b 2 0 /* USBOE */
&qe_pio_b 3 0 /* USBTP */
&qe_pio_b 8 0 /* USBTN */
&qe_pio_b 9 0 /* USBRP */
&qe_pio_b 11 0 /* USBRN */
&qe_pio_e 20 0 /* SPEED */
&qe_pio_e 21 0 /* POWER */>;
};

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* Serial
Currently defined compatibles:
- fsl,cpm1-smc-uart
- fsl,cpm2-smc-uart
- fsl,cpm1-scc-uart
- fsl,cpm2-scc-uart
- fsl,qe-uart
Example:
serial@11a00 {
device_type = "serial";
compatible = "fsl,mpc8272-scc-uart",
"fsl,cpm2-scc-uart";
reg = <11a00 20 8000 100>;
interrupts = <28 8>;
interrupt-parent = <&PIC>;
fsl,cpm-brg = <1>;
fsl,cpm-command = <00800000>;
};

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* Freescale Display Interface Unit
The Freescale DIU is a LCD controller, with proper hardware, it can also
drive DVI monitors.
Required properties:
- compatible : should be "fsl-diu".
- reg : should contain at least address and length of the DIU register
set.
- Interrupts : one DIU interrupt should be describe here.
Example (MPC8610HPCD):
display@2c000 {
compatible = "fsl,diu";
reg = <0x2c000 100>;
interrupts = <72 2>;
interrupt-parent = <&mpic>;
};

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* Freescale 83xx DMA Controller
Freescale PowerPC 83xx have on chip general purpose DMA controllers.
Required properties:
- compatible : compatible list, contains 2 entries, first is
"fsl,CHIP-dma", where CHIP is the processor
(mpc8349, mpc8360, etc.) and the second is
"fsl,elo-dma"
- reg : <registers mapping for DMA general status reg>
- ranges : Should be defined as specified in 1) to describe the
DMA controller channels.
- cell-index : controller index. 0 for controller @ 0x8100
- interrupts : <interrupt mapping for DMA IRQ>
- interrupt-parent : optional, if needed for interrupt mapping
- DMA channel nodes:
- compatible : compatible list, contains 2 entries, first is
"fsl,CHIP-dma-channel", where CHIP is the processor
(mpc8349, mpc8350, etc.) and the second is
"fsl,elo-dma-channel"
- reg : <registers mapping for channel>
- cell-index : dma channel index starts at 0.
Optional properties:
- interrupts : <interrupt mapping for DMA channel IRQ>
(on 83xx this is expected to be identical to
the interrupts property of the parent node)
- interrupt-parent : optional, if needed for interrupt mapping
Example:
dma@82a8 {
#address-cells = <1>;
#size-cells = <1>;
compatible = "fsl,mpc8349-dma", "fsl,elo-dma";
reg = <82a8 4>;
ranges = <0 8100 1a4>;
interrupt-parent = <&ipic>;
interrupts = <47 8>;
cell-index = <0>;
dma-channel@0 {
compatible = "fsl,mpc8349-dma-channel", "fsl,elo-dma-channel";
cell-index = <0>;
reg = <0 80>;
};
dma-channel@80 {
compatible = "fsl,mpc8349-dma-channel", "fsl,elo-dma-channel";
cell-index = <1>;
reg = <80 80>;
};
dma-channel@100 {
compatible = "fsl,mpc8349-dma-channel", "fsl,elo-dma-channel";
cell-index = <2>;
reg = <100 80>;
};
dma-channel@180 {
compatible = "fsl,mpc8349-dma-channel", "fsl,elo-dma-channel";
cell-index = <3>;
reg = <180 80>;
};
};
* Freescale 85xx/86xx DMA Controller
Freescale PowerPC 85xx/86xx have on chip general purpose DMA controllers.
Required properties:
- compatible : compatible list, contains 2 entries, first is
"fsl,CHIP-dma", where CHIP is the processor
(mpc8540, mpc8540, etc.) and the second is
"fsl,eloplus-dma"
- reg : <registers mapping for DMA general status reg>
- cell-index : controller index. 0 for controller @ 0x21000,
1 for controller @ 0xc000
- ranges : Should be defined as specified in 1) to describe the
DMA controller channels.
- DMA channel nodes:
- compatible : compatible list, contains 2 entries, first is
"fsl,CHIP-dma-channel", where CHIP is the processor
(mpc8540, mpc8560, etc.) and the second is
"fsl,eloplus-dma-channel"
- cell-index : dma channel index starts at 0.
- reg : <registers mapping for channel>
- interrupts : <interrupt mapping for DMA channel IRQ>
- interrupt-parent : optional, if needed for interrupt mapping
Example:
dma@21300 {
#address-cells = <1>;
#size-cells = <1>;
compatible = "fsl,mpc8540-dma", "fsl,eloplus-dma";
reg = <21300 4>;
ranges = <0 21100 200>;
cell-index = <0>;
dma-channel@0 {
compatible = "fsl,mpc8540-dma-channel", "fsl,eloplus-dma-channel";
reg = <0 80>;
cell-index = <0>;
interrupt-parent = <&mpic>;
interrupts = <14 2>;
};
dma-channel@80 {
compatible = "fsl,mpc8540-dma-channel", "fsl,eloplus-dma-channel";
reg = <80 80>;
cell-index = <1>;
interrupt-parent = <&mpic>;
interrupts = <15 2>;
};
dma-channel@100 {
compatible = "fsl,mpc8540-dma-channel", "fsl,eloplus-dma-channel";
reg = <100 80>;
cell-index = <2>;
interrupt-parent = <&mpic>;
interrupts = <16 2>;
};
dma-channel@180 {
compatible = "fsl,mpc8540-dma-channel", "fsl,eloplus-dma-channel";
reg = <180 80>;
cell-index = <3>;
interrupt-parent = <&mpic>;
interrupts = <17 2>;
};
};

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* Freescale General-purpose Timers Module
Required properties:
- compatible : should be
"fsl,<chip>-gtm", "fsl,gtm" for SOC GTMs
"fsl,<chip>-qe-gtm", "fsl,qe-gtm", "fsl,gtm" for QE GTMs
"fsl,<chip>-cpm2-gtm", "fsl,cpm2-gtm", "fsl,gtm" for CPM2 GTMs
- reg : should contain gtm registers location and length (0x40).
- interrupts : should contain four interrupts.
- interrupt-parent : interrupt source phandle.
- clock-frequency : specifies the frequency driving the timer.
Example:
timer@500 {
compatible = "fsl,mpc8360-gtm", "fsl,gtm";
reg = <0x500 0x40>;
interrupts = <90 8 78 8 84 8 72 8>;
interrupt-parent = <&ipic>;
/* filled by u-boot */
clock-frequency = <0>;
};
timer@440 {
compatible = "fsl,mpc8360-qe-gtm", "fsl,qe-gtm", "fsl,gtm";
reg = <0x440 0x40>;
interrupts = <12 13 14 15>;
interrupt-parent = <&qeic>;
/* filled by u-boot */
clock-frequency = <0>;
};

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* Global Utilities Block
The global utilities block controls power management, I/O device
enabling, power-on-reset configuration monitoring, general-purpose
I/O signal configuration, alternate function selection for multiplexed
signals, and clock control.
Required properties:
- compatible : Should define the compatible device type for
global-utilities.
- reg : Offset and length of the register set for the device.
Recommended properties:
- fsl,has-rstcr : Indicates that the global utilities register set
contains a functioning "reset control register" (i.e. the board
is wired to reset upon setting the HRESET_REQ bit in this register).
Example:
global-utilities@e0000 { /* global utilities block */
compatible = "fsl,mpc8548-guts";
reg = <e0000 1000>;
fsl,has-rstcr;
};

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* I2C
Required properties :
- device_type : Should be "i2c"
- reg : Offset and length of the register set for the device
Recommended properties :
- compatible : Should be "fsl-i2c" for parts compatible with
Freescale I2C specifications.
- interrupts : <a b> where a is the interrupt number and b is a
field that represents an encoding of the sense and level
information for the interrupt. This should be encoded based on
the information in section 2) depending on the type of interrupt
controller you have.
- interrupt-parent : the phandle for the interrupt controller that
services interrupts for this device.
- dfsrr : boolean; if defined, indicates that this I2C device has
a digital filter sampling rate register
- fsl5200-clocking : boolean; if defined, indicated that this device
uses the FSL 5200 clocking mechanism.
Example :
i2c@3000 {
interrupt-parent = <40000>;
interrupts = <1b 3>;
reg = <3000 18>;
device_type = "i2c";
compatible = "fsl-i2c";
dfsrr;
};

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* Chipselect/Local Bus
Properties:
- name : Should be localbus
- #address-cells : Should be either two or three. The first cell is the
chipselect number, and the remaining cells are the
offset into the chipselect.
- #size-cells : Either one or two, depending on how large each chipselect
can be.
- ranges : Each range corresponds to a single chipselect, and cover
the entire access window as configured.
Example:
localbus@f0010100 {
compatible = "fsl,mpc8272-localbus",
"fsl,pq2-localbus";
#address-cells = <2>;
#size-cells = <1>;
reg = <f0010100 40>;
ranges = <0 0 fe000000 02000000
1 0 f4500000 00008000>;
flash@0,0 {
compatible = "jedec-flash";
reg = <0 0 2000000>;
bank-width = <4>;
device-width = <1>;
};
board-control@1,0 {
reg = <1 0 20>;
compatible = "fsl,mpc8272ads-bcsr";
};
};

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Freescale MPC8349E-mITX-compatible Power Management Micro Controller Unit (MCU)
Required properties:
- compatible : "fsl,<mcu-chip>-<board>", "fsl,mcu-mpc8349emitx".
- reg : should specify I2C address (0x0a).
- #gpio-cells : should be 2.
- gpio-controller : should be present.
Example:
mcu@0a {
#gpio-cells = <2>;
compatible = "fsl,mc9s08qg8-mpc8349emitx",
"fsl,mcu-mpc8349emitx";
reg = <0x0a>;
gpio-controller;
};

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* Freescale MSI interrupt controller
Reguired properities:
- compatible : compatible list, contains 2 entries,
first is "fsl,CHIP-msi", where CHIP is the processor(mpc8610, mpc8572,
etc.) and the second is "fsl,mpic-msi" or "fsl,ipic-msi" depending on
the parent type.
- reg : should contain the address and the length of the shared message
interrupt register set.
- msi-available-ranges: use <start count> style section to define which
msi interrupt can be used in the 256 msi interrupts. This property is
optional, without this, all the 256 MSI interrupts can be used.
- interrupts : each one of the interrupts here is one entry per 32 MSIs,
and routed to the host interrupt controller. the interrupts should
be set as edge sensitive.
- interrupt-parent: the phandle for the interrupt controller
that services interrupts for this device. for 83xx cpu, the interrupts
are routed to IPIC, and for 85xx/86xx cpu the interrupts are routed
to MPIC.
Example:
msi@41600 {
compatible = "fsl,mpc8610-msi", "fsl,mpic-msi";
reg = <0x41600 0x80>;
msi-available-ranges = <0 0x100>;
interrupts = <
0xe0 0
0xe1 0
0xe2 0
0xe3 0
0xe4 0
0xe5 0
0xe6 0
0xe7 0>;
interrupt-parent = <&mpic>;
};

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* Power Management Controller
Properties:
- compatible: "fsl,<chip>-pmc".
"fsl,mpc8349-pmc" should be listed for any chip whose PMC is
compatible. "fsl,mpc8313-pmc" should also be listed for any chip
whose PMC is compatible, and implies deep-sleep capability.
"fsl,mpc8548-pmc" should be listed for any chip whose PMC is
compatible. "fsl,mpc8536-pmc" should also be listed for any chip
whose PMC is compatible, and implies deep-sleep capability.
"fsl,mpc8641d-pmc" should be listed for any chip whose PMC is
compatible; all statements below that apply to "fsl,mpc8548-pmc" also
apply to "fsl,mpc8641d-pmc".
Compatibility does not include bit assigments in SCCR/PMCDR/DEVDISR; these
bit assigments are indicated via the sleep specifier in each device's
sleep property.
- reg: For devices compatible with "fsl,mpc8349-pmc", the first resource
is the PMC block, and the second resource is the Clock Configuration
block.
For devices compatible with "fsl,mpc8548-pmc", the first resource
is a 32-byte block beginning with DEVDISR.
- interrupts: For "fsl,mpc8349-pmc"-compatible devices, the first
resource is the PMC block interrupt.
- fsl,mpc8313-wakeup-timer: For "fsl,mpc8313-pmc"-compatible devices,
this is a phandle to an "fsl,gtm" node on which timer 4 can be used as
a wakeup source from deep sleep.
Sleep specifiers:
fsl,mpc8349-pmc: Sleep specifiers consist of one cell. For each bit
that is set in the cell, the corresponding bit in SCCR will be saved
and cleared on suspend, and restored on resume. This sleep controller
supports disabling and resuming devices at any time.
fsl,mpc8536-pmc: Sleep specifiers consist of three cells, the third of
which will be ORed into PMCDR upon suspend, and cleared from PMCDR
upon resume. The first two cells are as described for fsl,mpc8578-pmc.
This sleep controller only supports disabling devices during system
sleep, or permanently.
fsl,mpc8548-pmc: Sleep specifiers consist of one or two cells, the
first of which will be ORed into DEVDISR (and the second into
DEVDISR2, if present -- this cell should be zero or absent if the
hardware does not have DEVDISR2) upon a request for permanent device
disabling. This sleep controller does not support configuring devices
to disable during system sleep (unless supported by another compatible
match), or dynamically.
Example:
power@b00 {
compatible = "fsl,mpc8313-pmc", "fsl,mpc8349-pmc";
reg = <0xb00 0x100 0xa00 0x100>;
interrupts = <80 8>;
};

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* Freescale 8xxx/3.0 Gb/s SATA nodes
SATA nodes are defined to describe on-chip Serial ATA controllers.
Each SATA port should have its own node.
Required properties:
- compatible : compatible list, contains 2 entries, first is
"fsl,CHIP-sata", where CHIP is the processor
(mpc8315, mpc8379, etc.) and the second is
"fsl,pq-sata"
- interrupts : <interrupt mapping for SATA IRQ>
- cell-index : controller index.
1 for controller @ 0x18000
2 for controller @ 0x19000
3 for controller @ 0x1a000
4 for controller @ 0x1b000
Optional properties:
- interrupt-parent : optional, if needed for interrupt mapping
- reg : <registers mapping>
Example:
sata@18000 {
compatible = "fsl,mpc8379-sata", "fsl,pq-sata";
reg = <0x18000 0x1000>;
cell-index = <1>;
interrupts = <2c 8>;
interrupt-parent = < &ipic >;
};

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Freescale SoC SEC Security Engines
Required properties:
- compatible : Should contain entries for this and backward compatible
SEC versions, high to low, e.g., "fsl,sec2.1", "fsl,sec2.0"
- reg : Offset and length of the register set for the device
- interrupts : the SEC's interrupt number
- fsl,num-channels : An integer representing the number of channels
available.
- fsl,channel-fifo-len : An integer representing the number of
descriptor pointers each channel fetch fifo can hold.
- fsl,exec-units-mask : The bitmask representing what execution units
(EUs) are available. It's a single 32-bit cell. EU information
should be encoded following the SEC's Descriptor Header Dword
EU_SEL0 field documentation, i.e. as follows:
bit 0 = reserved - should be 0
bit 1 = set if SEC has the ARC4 EU (AFEU)
bit 2 = set if SEC has the DES/3DES EU (DEU)
bit 3 = set if SEC has the message digest EU (MDEU/MDEU-A)
bit 4 = set if SEC has the random number generator EU (RNG)
bit 5 = set if SEC has the public key EU (PKEU)
bit 6 = set if SEC has the AES EU (AESU)
bit 7 = set if SEC has the Kasumi EU (KEU)
bit 8 = set if SEC has the CRC EU (CRCU)
bit 11 = set if SEC has the message digest EU extended alg set (MDEU-B)
remaining bits are reserved for future SEC EUs.
- fsl,descriptor-types-mask : The bitmask representing what descriptors
are available. It's a single 32-bit cell. Descriptor type information
should be encoded following the SEC's Descriptor Header Dword DESC_TYPE
field documentation, i.e. as follows:
bit 0 = set if SEC supports the aesu_ctr_nonsnoop desc. type
bit 1 = set if SEC supports the ipsec_esp descriptor type
bit 2 = set if SEC supports the common_nonsnoop desc. type
bit 3 = set if SEC supports the 802.11i AES ccmp desc. type
bit 4 = set if SEC supports the hmac_snoop_no_afeu desc. type
bit 5 = set if SEC supports the srtp descriptor type
bit 6 = set if SEC supports the non_hmac_snoop_no_afeu desc.type
bit 7 = set if SEC supports the pkeu_assemble descriptor type
bit 8 = set if SEC supports the aesu_key_expand_output desc.type
bit 9 = set if SEC supports the pkeu_ptmul descriptor type
bit 10 = set if SEC supports the common_nonsnoop_afeu desc. type
bit 11 = set if SEC supports the pkeu_ptadd_dbl descriptor type
..and so on and so forth.
Optional properties:
- interrupt-parent : the phandle for the interrupt controller that
services interrupts for this device.
Example:
/* MPC8548E */
crypto@30000 {
compatible = "fsl,sec2.1", "fsl,sec2.0";
reg = <0x30000 0x10000>;
interrupts = <29 2>;
interrupt-parent = <&mpic>;
fsl,num-channels = <4>;
fsl,channel-fifo-len = <24>;
fsl,exec-units-mask = <0xfe>;
fsl,descriptor-types-mask = <0x12b0ebf>;
};

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* SPI (Serial Peripheral Interface)
Required properties:
- cell-index : SPI controller index.
- compatible : should be "fsl,spi".
- mode : the SPI operation mode, it can be "cpu" or "cpu-qe".
- reg : Offset and length of the register set for the device
- interrupts : <a b> where a is the interrupt number and b is a
field that represents an encoding of the sense and level
information for the interrupt. This should be encoded based on
the information in section 2) depending on the type of interrupt
controller you have.
- interrupt-parent : the phandle for the interrupt controller that
services interrupts for this device.
Example:
spi@4c0 {
cell-index = <0>;
compatible = "fsl,spi";
reg = <4c0 40>;
interrupts = <82 0>;
interrupt-parent = <700>;
mode = "cpu";
};

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Freescale Synchronous Serial Interface
The SSI is a serial device that communicates with audio codecs. It can
be programmed in AC97, I2S, left-justified, or right-justified modes.
Required properties:
- compatible : compatible list, containing "fsl,ssi"
- cell-index : the SSI, <0> = SSI1, <1> = SSI2, and so on
- reg : offset and length of the register set for the device
- interrupts : <a b> where a is the interrupt number and b is a
field that represents an encoding of the sense and
level information for the interrupt. This should be
encoded based on the information in section 2)
depending on the type of interrupt controller you
have.
- interrupt-parent : the phandle for the interrupt controller that
services interrupts for this device.
- fsl,mode : the operating mode for the SSI interface
"i2s-slave" - I2S mode, SSI is clock slave
"i2s-master" - I2S mode, SSI is clock master
"lj-slave" - left-justified mode, SSI is clock slave
"lj-master" - l.j. mode, SSI is clock master
"rj-slave" - right-justified mode, SSI is clock slave
"rj-master" - r.j., SSI is clock master
"ac97-slave" - AC97 mode, SSI is clock slave
"ac97-master" - AC97 mode, SSI is clock master
Optional properties:
- codec-handle : phandle to a 'codec' node that defines an audio
codec connected to this SSI. This node is typically
a child of an I2C or other control node.
Child 'codec' node required properties:
- compatible : compatible list, contains the name of the codec
Child 'codec' node optional properties:
- clock-frequency : The frequency of the input clock, which typically
comes from an on-board dedicated oscillator.

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* MDIO IO device
The MDIO is a bus to which the PHY devices are connected. For each
device that exists on this bus, a child node should be created. See
the definition of the PHY node below for an example of how to define
a PHY.
Required properties:
- reg : Offset and length of the register set for the device
- compatible : Should define the compatible device type for the
mdio. Currently, this is most likely to be "fsl,gianfar-mdio"
Example:
mdio@24520 {
reg = <24520 20>;
compatible = "fsl,gianfar-mdio";
ethernet-phy@0 {
......
};
};
* Gianfar-compatible ethernet nodes
Properties:
- device_type : Should be "network"
- model : Model of the device. Can be "TSEC", "eTSEC", or "FEC"
- compatible : Should be "gianfar"
- reg : Offset and length of the register set for the device
- local-mac-address : List of bytes representing the ethernet address of
this controller
- interrupts : For FEC devices, the first interrupt is the device's
interrupt. For TSEC and eTSEC devices, the first interrupt is
transmit, the second is receive, and the third is error.
- phy-handle : The phandle for the PHY connected to this ethernet
controller.
- fixed-link : <a b c d e> where a is emulated phy id - choose any,
but unique to the all specified fixed-links, b is duplex - 0 half,
1 full, c is link speed - d#10/d#100/d#1000, d is pause - 0 no
pause, 1 pause, e is asym_pause - 0 no asym_pause, 1 asym_pause.
- phy-connection-type : a string naming the controller/PHY interface type,
i.e., "mii" (default), "rmii", "gmii", "rgmii", "rgmii-id", "sgmii",
"tbi", or "rtbi". This property is only really needed if the connection
is of type "rgmii-id", as all other connection types are detected by
hardware.
- fsl,magic-packet : If present, indicates that the hardware supports
waking up via magic packet.
Example:
ethernet@24000 {
device_type = "network";
model = "TSEC";
compatible = "gianfar";
reg = <0x24000 0x1000>;
local-mac-address = [ 00 E0 0C 00 73 00 ];
interrupts = <29 2 30 2 34 2>;
interrupt-parent = <&mpic>;
phy-handle = <&phy0>
};

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Freescale Localbus UPM programmed to work with NAND flash
Required properties:
- compatible : "fsl,upm-nand".
- reg : should specify localbus chip select and size used for the chip.
- fsl,upm-addr-offset : UPM pattern offset for the address latch.
- fsl,upm-cmd-offset : UPM pattern offset for the command latch.
- gpios : may specify optional GPIO connected to the Ready-Not-Busy pin.
Example:
upm@1,0 {
compatible = "fsl,upm-nand";
reg = <1 0 1>;
fsl,upm-addr-offset = <16>;
fsl,upm-cmd-offset = <8>;
gpios = <&qe_pio_e 18 0>;
flash {
#address-cells = <1>;
#size-cells = <1>;
compatible = "...";
partition@0 {
...
};
};
};

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Freescale SOC USB controllers
The device node for a USB controller that is part of a Freescale
SOC is as described in the document "Open Firmware Recommended
Practice : Universal Serial Bus" with the following modifications
and additions :
Required properties :
- compatible : Should be "fsl-usb2-mph" for multi port host USB
controllers, or "fsl-usb2-dr" for dual role USB controllers
- phy_type : For multi port host USB controllers, should be one of
"ulpi", or "serial". For dual role USB controllers, should be
one of "ulpi", "utmi", "utmi_wide", or "serial".
- reg : Offset and length of the register set for the device
- port0 : boolean; if defined, indicates port0 is connected for
fsl-usb2-mph compatible controllers. Either this property or
"port1" (or both) must be defined for "fsl-usb2-mph" compatible
controllers.
- port1 : boolean; if defined, indicates port1 is connected for
fsl-usb2-mph compatible controllers. Either this property or
"port0" (or both) must be defined for "fsl-usb2-mph" compatible
controllers.
- dr_mode : indicates the working mode for "fsl-usb2-dr" compatible
controllers. Can be "host", "peripheral", or "otg". Default to
"host" if not defined for backward compatibility.
Recommended properties :
- interrupts : <a b> where a is the interrupt number and b is a
field that represents an encoding of the sense and level
information for the interrupt. This should be encoded based on
the information in section 2) depending on the type of interrupt
controller you have.
- interrupt-parent : the phandle for the interrupt controller that
services interrupts for this device.
Example multi port host USB controller device node :
usb@22000 {
compatible = "fsl-usb2-mph";
reg = <22000 1000>;
#address-cells = <1>;
#size-cells = <0>;
interrupt-parent = <700>;
interrupts = <27 1>;
phy_type = "ulpi";
port0;
port1;
};
Example dual role USB controller device node :
usb@23000 {
compatible = "fsl-usb2-dr";
reg = <23000 1000>;
#address-cells = <1>;
#size-cells = <0>;
interrupt-parent = <700>;
interrupts = <26 1>;
dr_mode = "otg";
phy = "ulpi";
};

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LED connected to GPIO
Required properties:
- compatible : should be "gpio-led".
- label : (optional) the label for this LED. If omitted, the label is
taken from the node name (excluding the unit address).
- gpios : should specify LED GPIO.
Example:
led@0 {
compatible = "gpio-led";
label = "hdd";
gpios = <&mcu_pio 0 1>;
};

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rfkill - RF switch subsystem support
====================================
1 Implementation details
2 Driver support
3 Userspace support
1 Introduction
2 Implementation details
3 Kernel driver guidelines
3.1 wireless device drivers
3.2 platform/switch drivers
3.3 input device drivers
4 Kernel API
5 Userspace support
1. Introduction:
The rfkill switch subsystem exists to add a generic interface to circuitry that
can enable or disable the signal output of a wireless *transmitter* of any
type. By far, the most common use is to disable radio-frequency transmitters.
Note that disabling the signal output means that the the transmitter is to be
made to not emit any energy when "blocked". rfkill is not about blocking data
transmissions, it is about blocking energy emission.
The rfkill subsystem offers support for keys and switches often found on
laptops to enable wireless devices like WiFi and Bluetooth, so that these keys
and switches actually perform an action in all wireless devices of a given type
attached to the system.
The buttons to enable and disable the wireless transmitters are important in
situations where the user is for example using his laptop on a location where
radio-frequency transmitters _must_ be disabled (e.g. airplanes).
Because of this requirement, userspace support for the keys should not be made
mandatory. Because userspace might want to perform some additional smarter
tasks when the key is pressed, rfkill provides userspace the possibility to
take over the task to handle the key events.
===============================================================================
1: Implementation details
2: Implementation details
The rfkill switch subsystem offers support for keys often found on laptops
to enable wireless devices like WiFi and Bluetooth.
The rfkill subsystem is composed of various components: the rfkill class, the
rfkill-input module (an input layer handler), and some specific input layer
events.
This is done by providing the user 3 possibilities:
1 - The rfkill system handles all events; userspace is not aware of events.
2 - The rfkill system handles all events; userspace is informed about the events.
3 - The rfkill system does not handle events; userspace handles all events.
The rfkill class provides kernel drivers with an interface that allows them to
know when they should enable or disable a wireless network device transmitter.
This is enabled by the CONFIG_RFKILL Kconfig option.
The buttons to enable and disable the wireless radios are important in
situations where the user is for example using his laptop on a location where
wireless radios _must_ be disabled (e.g. airplanes).
Because of this requirement, userspace support for the keys should not be
made mandatory. Because userspace might want to perform some additional smarter
tasks when the key is pressed, rfkill still provides userspace the possibility
to take over the task to handle the key events.
The rfkill class support makes sure userspace will be notified of all state
changes on rfkill devices through uevents. It provides a notification chain
for interested parties in the kernel to also get notified of rfkill state
changes in other drivers. It creates several sysfs entries which can be used
by userspace. See section "Userspace support".
The system inside the kernel has been split into 2 separate sections:
1 - RFKILL
2 - RFKILL_INPUT
The rfkill-input module provides the kernel with the ability to implement a
basic response when the user presses a key or button (or toggles a switch)
related to rfkill functionality. It is an in-kernel implementation of default
policy of reacting to rfkill-related input events and neither mandatory nor
required for wireless drivers to operate. It is enabled by the
CONFIG_RFKILL_INPUT Kconfig option.
The first option enables rfkill support and will make sure userspace will
be notified of any events through the input device. It also creates several
sysfs entries which can be used by userspace. See section "Userspace support".
rfkill-input is a rfkill-related events input layer handler. This handler will
listen to all rfkill key events and will change the rfkill state of the
wireless devices accordingly. With this option enabled userspace could either
do nothing or simply perform monitoring tasks.
The second option provides an rfkill input handler. This handler will
listen to all rfkill key events and will toggle the radio accordingly.
With this option enabled userspace could either do nothing or simply
perform monitoring tasks.
The rfkill-input module also provides EPO (emergency power-off) functionality
for all wireless transmitters. This function cannot be overridden, and it is
always active. rfkill EPO is related to *_RFKILL_ALL input layer events.
Important terms for the rfkill subsystem:
In order to avoid confusion, we avoid the term "switch" in rfkill when it is
referring to an electronic control circuit that enables or disables a
transmitter. We reserve it for the physical device a human manipulates
(which is an input device, by the way):
rfkill switch:
A physical device a human manipulates. Its state can be perceived by
the kernel either directly (through a GPIO pin, ACPI GPE) or by its
effect on a rfkill line of a wireless device.
rfkill controller:
A hardware circuit that controls the state of a rfkill line, which a
kernel driver can interact with *to modify* that state (i.e. it has
either write-only or read/write access).
rfkill line:
An input channel (hardware or software) of a wireless device, which
causes a wireless transmitter to stop emitting energy (BLOCK) when it
is active. Point of view is extremely important here: rfkill lines are
always seen from the PoV of a wireless device (and its driver).
soft rfkill line/software rfkill line:
A rfkill line the wireless device driver can directly change the state
of. Related to rfkill_state RFKILL_STATE_SOFT_BLOCKED.
hard rfkill line/hardware rfkill line:
A rfkill line that works fully in hardware or firmware, and that cannot
be overridden by the kernel driver. The hardware device or the
firmware just exports its status to the driver, but it is read-only.
Related to rfkill_state RFKILL_STATE_HARD_BLOCKED.
The enum rfkill_state describes the rfkill state of a transmitter:
When a rfkill line or rfkill controller is in the RFKILL_STATE_UNBLOCKED state,
the wireless transmitter (radio TX circuit for example) is *enabled*. When the
it is in the RFKILL_STATE_SOFT_BLOCKED or RFKILL_STATE_HARD_BLOCKED, the
wireless transmitter is to be *blocked* from operating.
RFKILL_STATE_SOFT_BLOCKED indicates that a call to toggle_radio() can change
that state. RFKILL_STATE_HARD_BLOCKED indicates that a call to toggle_radio()
will not be able to change the state and will return with a suitable error if
attempts are made to set the state to RFKILL_STATE_UNBLOCKED.
RFKILL_STATE_HARD_BLOCKED is used by drivers to signal that the device is
locked in the BLOCKED state by a hardwire rfkill line (typically an input pin
that, when active, forces the transmitter to be disabled) which the driver
CANNOT override.
Full rfkill functionality requires two different subsystems to cooperate: the
input layer and the rfkill class. The input layer issues *commands* to the
entire system requesting that devices registered to the rfkill class change
state. The way this interaction happens is not complex, but it is not obvious
either:
Kernel Input layer:
* Generates KEY_WWAN, KEY_WLAN, KEY_BLUETOOTH, SW_RFKILL_ALL, and
other such events when the user presses certain keys, buttons, or
toggles certain physical switches.
THE INPUT LAYER IS NEVER USED TO PROPAGATE STATUS, NOTIFICATIONS OR THE
KIND OF STUFF AN ON-SCREEN-DISPLAY APPLICATION WOULD REPORT. It is
used to issue *commands* for the system to change behaviour, and these
commands may or may not be carried out by some kernel driver or
userspace application. It follows that doing user feedback based only
on input events is broken, as there is no guarantee that an input event
will be acted upon.
Most wireless communication device drivers implementing rfkill
functionality MUST NOT generate these events, and have no reason to
register themselves with the input layer. Doing otherwise is a common
misconception. There is an API to propagate rfkill status change
information, and it is NOT the input layer.
rfkill class:
* Calls a hook in a driver to effectively change the wireless
transmitter state;
* Keeps track of the wireless transmitter state (with help from
the driver);
* Generates userspace notifications (uevents) and a call to a
notification chain (kernel) when there is a wireless transmitter
state change;
* Connects a wireless communications driver with the common rfkill
control system, which, for example, allows actions such as
"switch all bluetooth devices offline" to be carried out by
userspace or by rfkill-input.
THE RFKILL CLASS NEVER ISSUES INPUT EVENTS. THE RFKILL CLASS DOES
NOT LISTEN TO INPUT EVENTS. NO DRIVER USING THE RFKILL CLASS SHALL
EVER LISTEN TO, OR ACT ON RFKILL INPUT EVENTS. Doing otherwise is
a layering violation.
Most wireless data communication drivers in the kernel have just to
implement the rfkill class API to work properly. Interfacing to the
input layer is not often required (and is very often a *bug*) on
wireless drivers.
Platform drivers often have to attach to the input layer to *issue*
(but never to listen to) rfkill events for rfkill switches, and also to
the rfkill class to export a control interface for the platform rfkill
controllers to the rfkill subsystem. This does NOT mean the rfkill
switch is attached to a rfkill class (doing so is almost always wrong).
It just means the same kernel module is the driver for different
devices (rfkill switches and rfkill controllers).
Userspace input handlers (uevents) or kernel input handlers (rfkill-input):
* Implements the policy of what should happen when one of the input
layer events related to rfkill operation is received.
* Uses the sysfs interface (userspace) or private rfkill API calls
to tell the devices registered with the rfkill class to change
their state (i.e. translates the input layer event into real
action).
* rfkill-input implements EPO by handling EV_SW SW_RFKILL_ALL 0
(power off all transmitters) in a special way: it ignores any
overrides and local state cache and forces all transmitters to the
RFKILL_STATE_SOFT_BLOCKED state (including those which are already
supposed to be BLOCKED). Note that the opposite event (power on all
transmitters) is handled normally.
Userspace uevent handler or kernel platform-specific drivers hooked to the
rfkill notifier chain:
* Taps into the rfkill notifier chain or to KOBJ_CHANGE uevents,
in order to know when a device that is registered with the rfkill
class changes state;
* Issues feedback notifications to the user;
* In the rare platforms where this is required, synthesizes an input
event to command all *OTHER* rfkill devices to also change their
statues when a specific rfkill device changes state.
===============================================================================
3: Kernel driver guidelines
Remember: point-of-view is everything for a driver that connects to the rfkill
subsystem. All the details below must be measured/perceived from the point of
view of the specific driver being modified.
The first thing one needs to know is whether his driver should be talking to
the rfkill class or to the input layer. In rare cases (platform drivers), it
could happen that you need to do both, as platform drivers often handle a
variety of devices in the same driver.
Do not mistake input devices for rfkill controllers. The only type of "rfkill
switch" device that is to be registered with the rfkill class are those
directly controlling the circuits that cause a wireless transmitter to stop
working (or the software equivalent of them), i.e. what we call a rfkill
controller. Every other kind of "rfkill switch" is just an input device and
MUST NOT be registered with the rfkill class.
A driver should register a device with the rfkill class when ALL of the
following conditions are met (they define a rfkill controller):
1. The device is/controls a data communications wireless transmitter;
2. The kernel can interact with the hardware/firmware to CHANGE the wireless
transmitter state (block/unblock TX operation);
3. The transmitter can be made to not emit any energy when "blocked":
rfkill is not about blocking data transmissions, it is about blocking
energy emission;
A driver should register a device with the input subsystem to issue
rfkill-related events (KEY_WLAN, KEY_BLUETOOTH, KEY_WWAN, KEY_WIMAX,
SW_RFKILL_ALL, etc) when ALL of the folowing conditions are met:
1. It is directly related to some physical device the user interacts with, to
command the O.S./firmware/hardware to enable/disable a data communications
wireless transmitter.
Examples of the physical device are: buttons, keys and switches the user
will press/touch/slide/switch to enable or disable the wireless
communication device.
2. It is NOT slaved to another device, i.e. there is no other device that
issues rfkill-related input events in preference to this one.
Please refer to the corner cases and examples section for more details.
When in doubt, do not issue input events. For drivers that should generate
input events in some platforms, but not in others (e.g. b43), the best solution
is to NEVER generate input events in the first place. That work should be
deferred to a platform-specific kernel module (which will know when to generate
events through the rfkill notifier chain) or to userspace. This avoids the
usual maintenance problems with DMI whitelisting.
Corner cases and examples:
====================================
2: Driver support
To build a driver with rfkill subsystem support, the driver should
depend on the Kconfig symbol RFKILL; it should _not_ depend on
RKFILL_INPUT.
1. If the device is an input device that, because of hardware or firmware,
causes wireless transmitters to be blocked regardless of the kernel's will, it
is still just an input device, and NOT to be registered with the rfkill class.
Unless key events trigger an interrupt to which the driver listens, polling
will be required to determine the key state changes. For this the input
layer providers the input-polldev handler.
2. If the wireless transmitter switch control is read-only, it is an input
device and not to be registered with the rfkill class (and maybe not to be made
an input layer event source either, see below).
A driver should implement a few steps to correctly make use of the
rfkill subsystem. First for non-polling drivers:
3. If there is some other device driver *closer* to the actual hardware the
user interacted with (the button/switch/key) to issue an input event, THAT is
the device driver that should be issuing input events.
- rfkill_allocate()
- input_allocate_device()
- rfkill_register()
- input_register_device()
E.g:
[RFKILL slider switch] -- [GPIO hardware] -- [WLAN card rf-kill input]
(platform driver) (wireless card driver)
For polling drivers:
The user is closer to the RFKILL slide switch plaform driver, so the driver
which must issue input events is the platform driver looking at the GPIO
hardware, and NEVER the wireless card driver (which is just a slave). It is
very likely that there are other leaves than just the WLAN card rf-kill input
(e.g. a bluetooth card, etc)...
- rfkill_allocate()
- input_allocate_polled_device()
- rfkill_register()
- input_register_polled_device()
On the other hand, some embedded devices do this:
When a key event has been detected, the correct event should be
sent over the input device which has been registered by the driver.
[RFKILL slider switch] -- [WLAN card rf-kill input]
(wireless card driver)
In this situation, the wireless card driver *could* register itself as an input
device and issue rf-kill related input events... but in order to AVOID the need
for DMI whitelisting, the wireless card driver does NOT do it. Userspace (HAL)
or a platform driver (that exists only on these embedded devices) will do the
dirty job of issuing the input events.
COMMON MISTAKES in kernel drivers, related to rfkill:
====================================
3: Userspace support
For each key an input device will be created which will send out the correct
key event when the rfkill key has been pressed.
1. NEVER confuse input device keys and buttons with input device switches.
1a. Switches are always set or reset. They report the current state
(on position or off position).
1b. Keys and buttons are either in the pressed or not-pressed state, and
that's it. A "button" that latches down when you press it, and
unlatches when you press it again is in fact a switch as far as input
devices go.
Add the SW_* events you need for switches, do NOT try to emulate a button using
KEY_* events just because there is no such SW_* event yet. Do NOT try to use,
for example, KEY_BLUETOOTH when you should be using SW_BLUETOOTH instead.
2. Input device switches (sources of EV_SW events) DO store their current state
(so you *must* initialize it by issuing a gratuitous input layer event on
driver start-up and also when resuming from sleep), and that state CAN be
queried from userspace through IOCTLs. There is no sysfs interface for this,
but that doesn't mean you should break things trying to hook it to the rfkill
class to get a sysfs interface :-)
3. Do not issue *_RFKILL_ALL events by default, unless you are sure it is the
correct event for your switch/button. These events are emergency power-off
events when they are trying to turn the transmitters off. An example of an
input device which SHOULD generate *_RFKILL_ALL events is the wireless-kill
switch in a laptop which is NOT a hotkey, but a real switch that kills radios
in hardware, even if the O.S. has gone to lunch. An example of an input device
which SHOULD NOT generate *_RFKILL_ALL events by default, is any sort of hot
key that does nothing by itself, as well as any hot key that is type-specific
(e.g. the one for WLAN).
3.1 Guidelines for wireless device drivers
------------------------------------------
1. Each independent transmitter in a wireless device (usually there is only one
transmitter per device) should have a SINGLE rfkill class attached to it.
2. If the device does not have any sort of hardware assistance to allow the
driver to rfkill the device, the driver should emulate it by taking all actions
required to silence the transmitter.
3. If it is impossible to silence the transmitter (i.e. it still emits energy,
even if it is just in brief pulses, when there is no data to transmit and there
is no hardware support to turn it off) do NOT lie to the users. Do not attach
it to a rfkill class. The rfkill subsystem does not deal with data
transmission, it deals with energy emission. If the transmitter is emitting
energy, it is not blocked in rfkill terms.
4. It doesn't matter if the device has multiple rfkill input lines affecting
the same transmitter, their combined state is to be exported as a single state
per transmitter (see rule 1).
This rule exists because users of the rfkill subsystem expect to get (and set,
when possible) the overall transmitter rfkill state, not of a particular rfkill
line.
Example of a WLAN wireless driver connected to the rfkill subsystem:
--------------------------------------------------------------------
A certain WLAN card has one input pin that causes it to block the transmitter
and makes the status of that input pin available (only for reading!) to the
kernel driver. This is a hard rfkill input line (it cannot be overridden by
the kernel driver).
The card also has one PCI register that, if manipulated by the driver, causes
it to block the transmitter. This is a soft rfkill input line.
It has also a thermal protection circuitry that shuts down its transmitter if
the card overheats, and makes the status of that protection available (only for
reading!) to the kernel driver. This is also a hard rfkill input line.
If either one of these rfkill lines are active, the transmitter is blocked by
the hardware and forced offline.
The driver should allocate and attach to its struct device *ONE* instance of
the rfkill class (there is only one transmitter).
It can implement the get_state() hook, and return RFKILL_STATE_HARD_BLOCKED if
either one of its two hard rfkill input lines are active. If the two hard
rfkill lines are inactive, it must return RFKILL_STATE_SOFT_BLOCKED if its soft
rfkill input line is active. Only if none of the rfkill input lines are
active, will it return RFKILL_STATE_UNBLOCKED.
If it doesn't implement the get_state() hook, it must make sure that its calls
to rfkill_force_state() are enough to keep the status always up-to-date, and it
must do a rfkill_force_state() on resume from sleep.
Every time the driver gets a notification from the card that one of its rfkill
lines changed state (polling might be needed on badly designed cards that don't
generate interrupts for such events), it recomputes the rfkill state as per
above, and calls rfkill_force_state() to update it.
The driver should implement the toggle_radio() hook, that:
1. Returns an error if one of the hardware rfkill lines are active, and the
caller asked for RFKILL_STATE_UNBLOCKED.
2. Activates the soft rfkill line if the caller asked for state
RFKILL_STATE_SOFT_BLOCKED. It should do this even if one of the hard rfkill
lines are active, effectively double-blocking the transmitter.
3. Deactivates the soft rfkill line if none of the hardware rfkill lines are
active and the caller asked for RFKILL_STATE_UNBLOCKED.
===============================================================================
4: Kernel API
To build a driver with rfkill subsystem support, the driver should depend on
(or select) the Kconfig symbol RFKILL; it should _not_ depend on RKFILL_INPUT.
The hardware the driver talks to may be write-only (where the current state
of the hardware is unknown), or read-write (where the hardware can be queried
about its current state).
The rfkill class will call the get_state hook of a device every time it needs
to know the *real* current state of the hardware. This can happen often.
Some hardware provides events when its status changes. In these cases, it is
best for the driver to not provide a get_state hook, and instead register the
rfkill class *already* with the correct status, and keep it updated using
rfkill_force_state() when it gets an event from the hardware.
There is no provision for a statically-allocated rfkill struct. You must
use rfkill_allocate() to allocate one.
You should:
- rfkill_allocate()
- modify rfkill fields (flags, name)
- modify state to the current hardware state (THIS IS THE ONLY TIME
YOU CAN ACCESS state DIRECTLY)
- rfkill_register()
The only way to set a device to the RFKILL_STATE_HARD_BLOCKED state is through
a suitable return of get_state() or through rfkill_force_state().
When a device is in the RFKILL_STATE_HARD_BLOCKED state, the only way to switch
it to a different state is through a suitable return of get_state() or through
rfkill_force_state().
If toggle_radio() is called to set a device to state RFKILL_STATE_SOFT_BLOCKED
when that device is already at the RFKILL_STATE_HARD_BLOCKED state, it should
not return an error. Instead, it should try to double-block the transmitter,
so that its state will change from RFKILL_STATE_HARD_BLOCKED to
RFKILL_STATE_SOFT_BLOCKED should the hardware blocking cease.
Please refer to the source for more documentation.
===============================================================================
5: Userspace support
rfkill devices issue uevents (with an action of "change"), with the following
environment variables set:
RFKILL_NAME
RFKILL_STATE
RFKILL_TYPE
The ABI for these variables is defined by the sysfs attributes. It is best
to take a quick look at the source to make sure of the possible values.
It is expected that HAL will trap those, and bridge them to DBUS, etc. These
events CAN and SHOULD be used to give feedback to the user about the rfkill
status of the system.
Input devices may issue events that are related to rfkill. These are the
various KEY_* events and SW_* events supported by rfkill-input.c.
******IMPORTANT******
When rfkill-input is ACTIVE, userspace is NOT TO CHANGE THE STATE OF AN RFKILL
SWITCH IN RESPONSE TO AN INPUT EVENT also handled by rfkill-input, unless it
has set to true the user_claim attribute for that particular switch. This rule
is *absolute*; do NOT violate it.
******IMPORTANT******
Userspace must not assume it is the only source of control for rfkill switches.
Their state CAN and WILL change due to firmware actions, direct user actions,
and the rfkill-input EPO override for *_RFKILL_ALL.
When rfkill-input is not active, userspace must initiate a rfkill status
change by writing to the "state" attribute in order for anything to happen.
Take particular care to implement EV_SW SW_RFKILL_ALL properly. When that
switch is set to OFF, *every* rfkill device *MUST* be immediately put into the
RFKILL_STATE_SOFT_BLOCKED state, no questions asked.
The following sysfs entries will be created:
name: Name assigned by driver to this key (interface or driver name).
type: Name of the key type ("wlan", "bluetooth", etc).
state: Current state of the key. 1: On, 0: Off.
state: Current state of the transmitter
0: RFKILL_STATE_SOFT_BLOCKED
transmitter is forced off, but one can override it
by a write to the state attribute;
1: RFKILL_STATE_UNBLOCKED
transmiter is NOT forced off, and may operate if
all other conditions for such operation are met
(such as interface is up and configured, etc);
2: RFKILL_STATE_HARD_BLOCKED
transmitter is forced off by something outside of
the driver's control. One cannot set a device to
this state through writes to the state attribute;
claim: 1: Userspace handles events, 0: Kernel handles events
Both the "state" and "claim" entries are also writable. For the "state" entry
this means that when 1 or 0 is written all radios, not yet in the requested
state, will be will be toggled accordingly.
this means that when 1 or 0 is written, the device rfkill state (if not yet in
the requested state), will be will be toggled accordingly.
For the "claim" entry writing 1 to it means that the kernel no longer handles
key events even though RFKILL_INPUT input was enabled. When "claim" has been
set to 0, userspace should make sure that it listens for the input events or
check the sysfs "state" entry regularly to correctly perform the required
tasks when the rkfill key is pressed.
check the sysfs "state" entry regularly to correctly perform the required tasks
when the rkfill key is pressed.
A note about input devices and EV_SW events:
In order to know the current state of an input device switch (like
SW_RFKILL_ALL), you will need to use an IOCTL. That information is not
available through sysfs in a generic way at this time, and it is not available
through the rfkill class AT ALL.

7
Documentation/scheduler/sched-domains.txt
Просмотреть файл

@ -61,10 +61,7 @@ builder by #define'ing ARCH_HASH_SCHED_DOMAIN, and exporting your
arch_init_sched_domains function. This function will attach domains to all
CPUs using cpu_attach_domain.
Implementors should change the line
#undef SCHED_DOMAIN_DEBUG
to
#define SCHED_DOMAIN_DEBUG
in kernel/sched.c as this enables an error checking parse of the sched domains
The sched-domains debugging infrastructure can be enabled by enabling
CONFIG_SCHED_DEBUG. This enables an error checking parse of the sched domains
which should catch most possible errors (described above). It also prints out
the domain structure in a visual format.

4
Documentation/scheduler/sched-rt-group.txt
Просмотреть файл

@ -51,9 +51,9 @@ needs only about 3% CPU time to do so, it can do with a 0.03 * 0.005s =
0.00015s. So this group can be scheduled with a period of 0.005s and a run time
of 0.00015s.
The remaining CPU time will be used for user input and other tass. Because
The remaining CPU time will be used for user input and other tasks. Because
realtime tasks have explicitly allocated the CPU time they need to perform
their tasks, buffer underruns in the graphocs or audio can be eliminated.
their tasks, buffer underruns in the graphics or audio can be eliminated.
NOTE: the above example is not fully implemented as of yet (2.6.25). We still
lack an EDF scheduler to make non-uniform periods usable.

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