Граф коммитов

72 Коммитов

Автор SHA1 Сообщение Дата
Artem Bityutskiy 4415626732 UBI: amend commentaries WRT dtype
Richard removed the "dtype" hint, but few commentaries were left and this patch
removes them. I've also added a better description about the "dtype" field in
the ubi-user.h for people who may ever wonder what was that dtype thing about.

This patch also adds an important note that it is better to use value "3" for
the "dtype" field.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
2012-05-20 20:25:59 +03:00
Richard Weinberger a65a0eb6d1 UBI: remove data type hint from ubi-user.h
This finally removes the data type hint from the UBI ABI.
>From now on the "dtype" field will be ignored and must not used
anymore.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
2012-05-20 20:25:59 +03:00
Artem Bityutskiy 2b00668ff9 mtd: document that MEMWRITE ioctl is NAND-specific
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2012-01-09 18:18:36 +00:00
Brian Norris 19fb4341ad mtd: kill old field for `struct mtd_info_user'
The ecctype and eccsize fields have been obsolete for a while. Since they
don't have any users, we can kill them and leave padding in their place
for now.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
2011-09-11 15:57:44 +03:00
Brian Norris 4180f24a7b mtd: document ABI
We're missing a lot of important documentation in include/mtd/mtd-abi.h:

* add a simple description of each ioctl (feel free to expand!)
* give full explanations of recently added and modified operations
* explain the usage of "RAW" that appear in different modes and types of
  operations
* fix some comment style along the way

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
2011-09-11 15:57:44 +03:00
Brian Norris e99d8b089a mtd: add MEMWRITE ioctl
Implement a new ioctl for writing both page data and OOB to flash at the
same time. This ioctl is intended to be a generic interface that can
replace other ioctls (MEMWRITEOOB and MEMWRITEOOB64) and cover the
functionality of several other old ones, e.g., MEMWRITE can:

* write autoplaced OOB instead of using ECCGETLAYOUT (deprecated) and
  working around the reserved areas
* write raw (no ECC) OOB instead of using MTDFILEMODE to set the
  per-file-descriptor MTD_FILE_MODE_RAW
* write raw (no ECC) data instead of using MTDFILEMODE
  (MTD_FILE_MODE_RAW) and using standard character device "write"

This ioctl is especially useful for MLC NAND, which cannot be written
twice (i.e., we cannot successfully write the page data and OOB in two
separate operations). Instead, MEMWRITE can write both in a single
operation.

Note that this ioctl is not affected by the MTD file mode (i.e.,
MTD_FILE_MODE_RAW vs. MTD_FILE_MODE_NORMAL), since it receives its write
mode as an input parameter.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
2011-09-11 15:56:25 +03:00
Brian Norris beb133fc16 mtd: rename MTD_MODE_* to MTD_FILE_MODE_*
These modes hold their state only for the life of their file descriptor,
and they overlap functionality with the MTD_OPS_* modes. Particularly,
MTD_MODE_RAW and MTD_OPS_RAW cover the same function: to provide raw
(i.e., without ECC) access to the flash. In fact, although it may not be
clear, MTD_MODE_RAW implied that operations should enable the
MTD_OPS_RAW mode.

Thus, we should be specific on what each mode means. This is a start,
where MTD_FILE_MODE_* actually represents a "file mode," not necessarily
a true global MTD mode.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
2011-09-11 15:29:36 +03:00
Brian Norris 0612b9ddc2 mtd: rename MTD_OOB_* to MTD_OPS_*
These modes are not necessarily for OOB only. Particularly, MTD_OOB_RAW
affected operations on in-band page data as well. To clarify these
options and to emphasize that their effect is applied per-operation, we
change the primary prefix to MTD_OPS_.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
2011-09-11 15:28:59 +03:00
Brian Norris 905c6bcdb4 mtd: move mtd_oob_mode_t to shared kernel/user space
We will want to use the MTD_OOB_{PLACE,AUTO,RAW} modes in user-space
applications through the introduction of new ioctls, so we should make
this enum a shared type.

This enum is now anonymous.

Artem: tweaked the patch.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
2011-09-11 15:26:20 +03:00
Brian Norris 93fad71c20 mtd: remove MEMSETOOBSEL macro definition
MEMSETOOBSEL is completely unused and useless. Remove the definition.

Note: it's probably best not to use this ioctl number in the future for
MTD, since that may cause conflicts between old kernels and new user
software (or new kernels and old user software).

Artem: leave a comment about MEMSETOOBSEL.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
2011-09-11 15:02:18 +03:00
Artem Bityutskiy feddbb34eb UBI: fix minor stylistic issues
Fix checkpatch.pl errors and warnings:

* space before tab
* line over 80 characters
* include linux/ioctl.h instead of asm/ioctl.h

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-04-14 11:34:41 +03:00
Artem Bityutskiy 3627924acf UBI: use __packed instead of __attribute__((packed))
There was an attempt to standartize various "__attribute__" and
other macros in order to have potentially portable and more
consistent code, see commit 82ddcb0405.

Note, that commit refers Rober Love's blog post, but the URL
is broken, the valid URL is:
http://blog.rlove.org/2005/10/with-little-help-from-your-compiler.html

Moreover, nowadays checkpatch.pl warns about using
__attribute__((packed)):

"WARNING: __packed is preferred over __attribute__((packed))"

It is not a big deal for UBI to use __packed, so let's do it.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-04-14 11:34:41 +03:00
Artem Bityutskiy e8e088de30 UBI: cleanup comments around volume properties
Cleanup and improve commentaries around the "set volume properties" ioctl,
make a simple indentation fix as well.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-04-14 11:34:40 +03:00
Artem Bityutskiy 6748482f41 UBI: re-name set volume properties ioctl
Rename the ioctl which sets volume properties from 'UBI_IOCSETPROP' to
'UBI_IOCSETVOLPROP' to reflect the fact that this ioctl is about volume
properties, not device properties. This is also consistent with the
other volume ioctl name - 'UBI_IOCVOLUP'.

The main motivation for the re-name, however, is that we are going
to introduce the per-UBI device "set properties" ioctl, so we need
good and logical naming.

At the same time, re-name the "set volume properties request" data
structure from 'struct ubi_set_prop_req' to
'struct ubi_set_vol_prop_req'.

And re-name 'UBI_PROP_DIRECT_WRITE' to 'UBI_VOL_PROP_DIRECT_WRITE'.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-04-14 11:34:40 +03:00
Rohit Hassan Sathyanarayan 17a22826bb mtd: Define MLC Flash as a different flash type
MLC NAND Flash has a different cell structure and differs in
functioning than the SLC NAND Flash. Hence we are considering it as
a different Flash type.

Signed-off-by: Rohit H.S <rohit.hs@samsung.com>
Signed-off-by: Raghav Gupta <gupta.raghav@samsung.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2010-10-25 00:50:20 +01:00
Brian Norris 0ceacf36e9 mtd: edit comments on deprecation of ioctl ECCGETLAYOUT
There were some improvements and additions necessary in the
comments explaining of the expansion of nand_ecclayout, the
introduction of nand_ecclayout_user, and the deprecation of the
ioctl ECCGETLAYOUT.

Also, I found a better placement for the macro MTD_MAX_ECCPOS_ENTRIES;
next to the definition of MTD_MAX_OOBFREE_ENTRIES in mtd-abi.h. The macro
is really only important for the ioctl code (found in drivers/mtd/mtdchar.c)
but since there are small edits being made to the user-space header, I
figured this is a better location.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2010-10-24 23:37:27 +01:00
Brian Norris cc26c3cd3d mtd: nand: expand nand_ecc_layout, deprecate ioctl ECCGETLAYOUT
struct nand_ecclayout is too small for many new chips; OOB regions can be as
large as 448 bytes and may increase more in the future. Thus, copying that
struct to user-space with the ECCGETLAYOUT ioctl is not a good idea; the ioctl
would have to be updated every time there's a change to the current largest
size.

Instead, the old nand_ecclayout is renamed to nand_ecclayout_user and a
new struct nand_ecclayout is created that can accomodate larger sizes and
expand without affecting the user-space. struct nand_ecclayout can still
be used in board drivers without modification -- at least for now.

A new function is provided to convert from the new to the old in order to
allow the deprecated ioctl to continue to work with truncated data. Perhaps
the ioctl, the conversion process, and the struct nand_ecclayout_user can be
removed altogether in the future.

Note: There are comments in nand/davinci_nand.c::nand_davinci_probe()
regarding this issue; this driver (and maybe others) can be updated to
account for extra space. All kernel drivers can use the expanded
nand_ecclayout as a drop-in replacement and ignore its benefits.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2010-10-24 23:37:24 +01:00
David Woodhouse a1452a3771 mtd: Update copyright notices
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2010-08-08 20:58:20 +01:00
Richard Cochran 9938424f0c mtd: add an ioctl to query the lock status of a flash sector
This patchs adds a way for user space programs to find out whether a
flash sector is locked. An optional driver method in the mtd_info struct
provides the information.

Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2010-08-02 09:03:41 +01:00
Artem Bityutskiy 24430abc88 Kill jffs2-user.h
This file does not define any kernel-userspace API, all
it does it defines few helpers for userspace. Instead,
userspace should have a private copy of this file.

The main (if not the only) user is the mtd-utils package, but
it already has a private copy of this file.

This patch also removes references to 'jffs2-user.h' from
'Kbuild' and MAINTAINERS' files.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2009-06-05 17:31:38 +01:00
Kevin Cernekee aea7cea9fa mtd: add OOB ioctls for >4GiB devices
Signed-off-by: Kevin Cernekee <kpc.mtd@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2009-05-29 15:27:07 +01:00
Kevin Cernekee 0dc54e9f33 mtd: add MEMERASE64 ioctl for >4GiB devices
New MEMERASE/MEMREADOOB/MEMWRITEOOB ioctls are needed in order to support
64-bit offsets into large NAND flash devices.

Signed-off-by: Kevin Cernekee <kpc.mtd@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2009-05-29 15:13:47 +01:00
Arnd Bergmann ccef7ab534 make MTD headers use strict integer types
The MTD headers traditionally use stdint types rather than
the kernel integer types. This converts them to do the
same as all the others.

Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-26 18:14:17 +01:00
Arnd Bergmann 85efde6f4e make exported headers use strict posix types
A number of standard posix types are used in exported headers, which
is not allowed if __STRICT_KERNEL_NAMES is defined. In order to
get rid of the non-__STRICT_KERNEL_NAMES part and to make sane headers
the default, we have to change them all to safe types.

There are also still some leftovers in reiserfs_fs.h, elfcore.h
and coda.h, but these files have not compiled in user space for
a long time.

This leaves out the various integer types ({u_,u,}int{8,16,32,64}_t),
which we take care of separately.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Cc: netdev@vger.kernel.org
Cc: linux-ppp@vger.kernel.org
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-26 18:14:14 +01:00
Jaswinder Singh Rajput 70c2ed65fe headers_check fix: mtd/inftl-user.h
fix the following 'make headers_check' warning:

  usr/include/mtd/inftl-user.h:61: found __[us]{8,16,32,64} type without #include <linux/types.h>

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
2009-01-31 00:13:34 +05:30
Sidney Amani 766fb95ba0 UBI: allow direct user-space I/O
Introduce a new ioctl UBI_IOCSETPROP to set properties
on a volume. Also add the first property:
UBI_PROP_DIRECT_WRITE, this property is used to set the
ability to use direct writes in userspace

Signed-off-by: Sidney Amani <seed@uffs.org>
Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2009-01-27 16:54:41 +02:00
Artem Bityutskiy f7fc6f3f33 UBI: improve ioctl commentaries
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2009-01-18 14:02:08 +02:00
Corentin Chary a27ce8f55d UBI: add ioctl for is_mapped operation
This patch adds ioctl to check if an LEB is mapped or not (as a
debugging option so far).

[Re-named ioctl to make it look the same as the other one and made
 some minor stylistic changes. Artem Bityutskiy.]

Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2009-01-18 14:02:08 +02:00
Corentin Chary c3da23be16 UBI: add ioctl for unmap operation
This patch adds ioctl for the LEB unmap operation (as a debugging
option so far).

[Re-named ioctl to make it look the same as the other one and made
 some minor stylistic changes. Artem Bityutskiy.]

Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2009-01-18 14:02:08 +02:00
Corentin Chary 141e6ebd1b UBI: add ioctl for map operation
This patch adds ioctl for the LEB map operation (as a debugging
option so far).

[Re-named ioctl to make it look the same as the other one and made
 some minor stylistic changes. Artem Bityutskiy.]

Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2009-01-18 14:02:08 +02:00
Frederik Schwarzer 025dfdafe7 trivial: fix then -> than typos in comments and documentation
- (better, more, bigger ...) then -> (...) than

Signed-off-by: Frederik Schwarzer <schwarzerf@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-01-06 11:28:06 +01:00
David Woodhouse ff877ea80e Merge branch 'linux-next' of git://git.infradead.org/~dedekind/ubi-2.6 2008-07-25 10:40:14 -04:00
Artem Bityutskiy 9c9ec14770 UBI: fix checkpatch.pl errors and warnings
Just out or curiousity ran checkpatch.pl for whole UBI,
and discovered there are quite a few of stylistic issues.
Fix them.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-07-24 13:36:09 +03:00
Artem Bityutskiy f40ac9cdf6 UBI: implement multiple volumes rename
Quite useful ioctl which allows to make atomic system upgrades.
The idea belongs to Richard Titmuss <richard_titmuss@logitech.com>

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-07-24 13:34:46 +03:00
Adrian Bunk 59018b6d2a MTD/JFFS2: remove CVS keywords
Once upon a time, the MTD repository was using CVS.

This patch therefore removes all usages of the no longer updated CVS
keywords from the MTD code.

This also includes code that printed them to the user.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-06-04 17:50:17 +01:00
Artem Bityutskiy 92a74f1c1c UBI: make ubi-header.h local
The new trend in linux is not to store headers which define
on-media format in the include/ directory, but instead, store
them locally. This is because these headers "do not define any
kernel<->userspace interface".

Do so for UBI as well.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-04-17 11:31:58 +03:00
David Woodhouse 6208e77e7f Merge git://git.infradead.org/~dedekind/ubi-2.6 2008-02-03 22:07:40 +11:00
Justin Treon e619a75ff6 [MTD] Unlocking all Intel flash that is locked on power up.
Patch for unlocking all Intel flash that has instant locking on power up.
The patch has been tested on Intel M18, P30 and J3D Strata Flash.
  1.    The automatic unlocking can be disabled for a particular partition
         in the map or the command line.
     a. For the bit mask in the map it should look like:
         .mask_flags   = MTD_POWERUP_LOCK,
     b. For the command line parsing it should look like:
         mtdparts=0x80000(bootloader)lk
  2.    This will only unlock parts with instant individual block locking.
         Intel parts with legacy unlocking will not be unlocked.

Signed-off-by: Justin Treon <justin_treon@yahoo.com>
Signed-off-by: Jared Hulbert <jaredeh@gmail.com>
Acked-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-02-03 18:25:16 +11:00
Artem Bityutskiy 866136827b UBI: introduce atomic LEB change ioctl
We have to be able to change individual LEBs for utilities like
ubifsck, ubifstune. For example, ubifsck has to be able to fix
errors on the media, ubifstune has to be able to change the
the superblock, hence this ioctl.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-01-25 16:41:25 +02:00
Artem Bityutskiy 91f2d53cd7 UBI: add layout volume information
Add more information about layout volume to make userspace tools
use the macros instead of constants. Also rename UBI_LAYOUT_VOL_ID
to make it consistent with other macros.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-01-25 16:41:25 +02:00
Artem Bityutskiy 4ccf8cffa9 UBI: add auto-resize feature
The problem: NAND flashes have different amount of initial bad physical
eraseblocks (marked as bad by the manufacturer). For example, for 256MiB
Samsung OneNAND flash there might be from 0 to 40 bad initial eraseblocks,
which is about 2%. When UBI is used as the base system, one needs to know
the exact amount of good physical eraseblocks, because this number is
needed to create the UBI image which is put to the devices during
production. But this number is not know, which forces us to use the
minimum number of good physical eraseblocks. And UBI additionally
reserves some percentage of physical eraseblocks for bad block handling
(default is 1%), so we have 1-3% of PEBs reserved at the end, depending
on the amount of initial bad PEBs. But it is desired to always have
1% (or more, depending on the configuration).

Solution: this patch adds an "auto-resize" flag to the volume table.
The volume which has the "auto-resize" flag will automatically be re-sized
(enlarged) on the first UBI initialization. UBI clears the flag when
the volume is re-sized. Only one volume may have the "auto-resize" flag.

So, the production UBI image may have one volume with "auto-resize"
flag set, and its size is automatically adjusted on the first boot
of the device.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-01-25 16:41:24 +02:00
Artem Bityutskiy 9b79cc0f84 UBI: introduce attach ioctls
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-12-26 19:15:17 +02:00
Christoph Hellwig 3261ebd7d4 UBI: kill homegrown endian macros
Kill UBI's homegrown endianess handling and replace it with
the standard kernel endianess handling.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-07-18 16:53:49 +03:00
Artem B. Bityutskiy 801c135ce7 UBI: Unsorted Block Images
UBI (Latin: "where?") manages multiple logical volumes on a single
flash device, specifically supporting NAND flash devices. UBI provides
a flexible partitioning concept which still allows for wear-levelling
across the whole flash device.

In a sense, UBI may be compared to the Logical Volume Manager
(LVM). Whereas LVM maps logical sector numbers to physical HDD sector
numbers, UBI maps logical eraseblocks to physical eraseblocks.

More information may be found at
http://www.linux-mtd.infradead.org/doc/ubi.html

Partitioning/Re-partitioning

  An UBI volume occupies a certain number of erase blocks. This is
  limited by a configured maximum volume size, which could also be
  viewed as the partition size. Each individual UBI volume's size can
  be changed independently of the other UBI volumes, provided that the
  sum of all volume sizes doesn't exceed a certain limit.

  UBI supports dynamic volumes and static volumes. Static volumes are
  read-only and their contents are protected by CRC check sums.

Bad eraseblocks handling

  UBI transparently handles bad eraseblocks. When a physical
  eraseblock becomes bad, it is substituted by a good physical
  eraseblock, and the user does not even notice this.

Scrubbing

  On a NAND flash bit flips can occur on any write operation,
  sometimes also on read. If bit flips persist on the device, at first
  they can still be corrected by ECC, but once they accumulate,
  correction will become impossible. Thus it is best to actively scrub
  the affected eraseblock, by first copying it to a free eraseblock
  and then erasing the original. The UBI layer performs this type of
  scrubbing under the covers, transparently to the UBI volume users.

Erase Counts

  UBI maintains an erase count header per eraseblock. This frees
  higher-level layers (like file systems) from doing this and allows
  for centralized erase count management instead. The erase counts are
  used by the wear-levelling algorithm in the UBI layer. The algorithm
  itself is exchangeable.

Booting from NAND

  For booting directly from NAND flash the hardware must at least be
  capable of fetching and executing a small portion of the NAND
  flash. Some NAND flash controllers have this kind of support. They
  usually limit the window to a few kilobytes in erase block 0. This
  "initial program loader" (IPL) must then contain sufficient logic to
  load and execute the next boot phase.

  Due to bad eraseblocks, which may be randomly scattered over the
  flash device, it is problematic to store the "secondary program
  loader" (SPL) statically. Also, due to bit-flips it may become
  corrupted over time. UBI allows to solve this problem gracefully by
  storing the SPL in a small static UBI volume.

UBI volumes vs. static partitions

  UBI volumes are still very similar to static MTD partitions:

    * both consist of eraseblocks (logical eraseblocks in case of UBI
      volumes, and physical eraseblocks in case of static partitions;
    * both support three basic operations - read, write, erase.

  But UBI volumes have the following advantages over traditional
  static MTD partitions:

    * there are no eraseblock wear-leveling constraints in case of UBI
      volumes, so the user should not care about this;
    * there are no bit-flips and bad eraseblocks in case of UBI volumes.

  So, UBI volumes may be considered as flash devices with relaxed
  restrictions.

Where can it be found?

  Documentation, kernel code and applications can be found in the MTD
  gits.

What are the applications for?

  The applications help to create binary flash images for two purposes: pfi
  files (partial flash images) for in-system update of UBI volumes, and plain
  binary images, with or without OOB data in case of NAND, for a manufacturing
  step. Furthermore some tools are/and will be created that allow flash content
  analysis after a system has crashed..

Who did UBI?

  The original ideas, where UBI is based on, were developed by Andreas
  Arnez, Frank Haverkamp and Thomas Gleixner. Josh W. Boyer and some others
  were involved too. The implementation of the kernel layer was done by Artem
  B. Bityutskiy. The user-space applications and tools were written by Oliver
  Lohmann with contributions from Frank Haverkamp, Andreas Arnez, and Artem.
  Joern Engel contributed a patch which modifies JFFS2 so that it can be run on
  a UBI volume. Thomas Gleixner did modifications to the NAND layer. Alexander
  Schmidt made some testing work as well as core functionality improvements.

Signed-off-by: Artem B. Bityutskiy <dedekind@linutronix.de>
Signed-off-by: Frank Haverkamp <haver@vnet.ibm.com>
2007-04-27 14:23:33 +03:00
Artem Bityutskiy 64f6071056 [MTD] remove unused ecctype,eccsize fields from struct mtd_info
Remove unused and broken mtd->ecctype and mtd->eccsize fields
from struct mtd_info. Do not remove them from userspace API
data structures (don't want to breake userspace) but mark them
as obsolete by a comment. Any userspace program which uses them
should be half-broken anyway, so this is more about saving
data structure size.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-02-09 15:27:12 +00:00
David Woodhouse 8a84fc15ae Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
Manually resolve conflict in include/mtd/Kbuild

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-10-01 17:55:53 +01:00
David Woodhouse 9663265626 [MTD] Remove #ifndef __KERNEL__ hack in <mtd/mtd-abi.h>
Now that we have headers_install, we don't need this crap.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-09-25 21:52:21 +01:00
Linus Torvalds e6e5fee142 Merge git://git.infradead.org/~dwmw2/hdroneline
* git://git.infradead.org/~dwmw2/hdroneline:
  [HEADERS] One line per header in Kbuild files to reduce conflicts

Manual (trivial) conflict resolution in include/asm-s390/Kbuild
2006-09-22 12:56:22 -07:00
Håvard Skinnemoen 187ef15268 [MTD] Unlock NOR flash automatically where necessary
Introduce the MTD_STUPID_LOCK flag which indicates that the flash chip is
always locked after power-up, so all sectors need to be unlocked before it
is usable.

If this flag is set, and the chip provides an unlock() operation,
mtd_add_device will unlock the whole MTD device if it's writeable.  This
means that non-writeable partitions will stay locked.

Set MTD_STUPID_LOCK in fixup_use_atmel_lock() so that these chips will work
as expected.

Signed-off-by: Håvard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-09-22 10:07:08 +01:00
David Woodhouse fadcfa33b6 [HEADERS] One line per header in Kbuild files to reduce conflicts
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-09-19 12:43:58 +01:00