FSI CFAMs support shorter commands that use a relative (or same) address
as the last. This change introduces a last_addr to the master state, and
uses it for subsequent reads/writes, and performs relative addressing
when a subsequent read/write is in range.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
For implementing relative addressing mode, we'll need to build a command
that is coherent with CFAM state. To do that, include the
build_command_* functions in the locked section of read/write/term.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: Joel Stanley <joel@jms.id.au>
Most SoC GPIO implementations, including the Aspeed one, have
synchronizers on the GPIO inputs. This means that the value
read from a GPIO is a couple of clocks old, from whatever clock
source feeds those synchronizers.
In practice, this means that in no-delay mode, we are using a
value that can potentially be a bit too old and too close to
the clock edge establishing the data on the other side of the link.
The voltage converters we use on some systems make this worse
and sensitive to things like voltage fluctuations etc... This is,
we believe, the cause of occasional CRC errors encountered during
heavy activity on the LPC bus.
This is fixed by introducing a dummy GPIO read before the actual
data read. It slows down SBEFIFO by about 15% (less than any delay
primitive) and the end result is so far solid.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
FSI_GPIO_DPOLL_CLOCKS is the number of clocks before sending
a DPOLL command after receiving a BUSY status. It should be
at least tSendDelay (16 clocks).
According to comments in the code, it needs to also be at least
21 clocks due to HW issues.
It's currently 100 clocks which impacts performances negatively
in some cases. Reduces it in half to 50 clocks which seems to
still be solid.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
FSI_GPIO_PRIME_SLAVE_CLOCKS is the number of clocks if the
"idle" phase between the end of a response and the beginning
of the next one. It corresponds to tSendDelay in the FSI
specification.
The default value in the slave is 16 clocks. 100 is way overkill
and significantly reduces the driver performance.
This changes it to 20 (which gives the HW a bit of margin still
just in case).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
This adds support for an optional device-tree property that
makes the driver skip all the delays around clocking the
GPIOs and set it in the device-tree of common POWER9 based
OpenPower platforms.
This useful on chips like the AST2500 where the GPIO block is
running at a fairly low clock frequency (25Mhz typically). In
this case, the delays are unnecessary and due to the low
precision of the timers, actually quite harmful in terms of
performance.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
We currently sample the input data right after we toggle the
clock low, then high. The slave establishes the data on the
rising edge, so this is not ideal. We should sample it on
the low phase instead.
This currently works because we have an extra delay, but subsequent
patches will remove it.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
Reduce time spent with interrupts disabled by limiting the critical
sections to bitbanging FSI symbols. We only need to ensure exclusive use
of the bus for an entire transfer, not that the transfer be performed in
atomic context.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: Joel Stanley <joel@jms.id.au>
An observation from trace output of the existing FSI tracepoints was
that the remote device was sometimes reporting as busy. Add a new
tracepoint reporting the busy count in order to get a better grip on how
often this is the case.
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Eddie James <eajames@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: Joel Stanley <joel@jms.id.au>
Prior to scanning a master check if the optional property
no-scan-on-init is present. If it is then avoid scanning. This is
necessary in cases where a master scan could interfere with another
FSI master on the same bus.
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Once we call fsi_master_unregister, the core will put_device,
potentially freeing the hub master. This change adds a comment
explaining the lifetime of an allocated fsi_master.
We then add a reference from the driver to the hub master, so it stays
around until we've finished ->remove().
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Tested-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To reduce amount of console output during boot / power up make
all normal path scan related messages debug type.
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This change populates device tree nodes for scanned FSI slaves and
engines. If the master populates ->of_node of the FSI master device,
we'll look for matching slaves, and under those slaves we'll look for
matching engines.
This means that FSI drivers will have their ->of_node pointer populated
if there's a corresponding DT node, which they can use for further
device discover.
Presence of device tree nodes is optional, and only required for
fsi device drivers that need extra properties, or subordinate devices,
to be enumerated.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Address checker fixed to allow one and two byte reads/writes.
Address alignments for each size verified.
Signed-off-by: Edward James <eajames@us.ibm.com>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This change introduces an 'external mode' for GPIO-based FSI masters,
allowing the clock and data lines to be driven by an external source.
For example, external mode is selected by a user when an external debug
device is attached to the FSI pins.
To do this, we need to set specific states for the trans, mux and enable
GPIOs, and prevent access to clk & data from the FSI core code (by
returning EBUSY).
External mode is controlled by a sysfs attribute, so add the relevant
information to Documentation/ABI/
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, we perform GPIO accesses in fsi_master_gpio_break and
fsi_master_link_enable, without holding cmd_lock. This change adds the
appropriate locking.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Christopher Bostic <clbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We'll want non-core fsi code to trigger a rescan, so introduce a
non-static fsi_master_rescan() function. Use this for the existing
unscan/scan behaviour too.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Christopher Bostic <clbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
No need to get into the submenu to disable all FSI-related config entries
Signed-off-by: Vincent Legoll <vincent.legoll@gmail.com>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The functions fsi_slave_report_and_clear_errors and fsi_slave_handle_error
are local to the source and do not need to be in global scope, so make
them static.
Cleans up sparse warnings:
symbol 'fsi_slave_report_and_clear_errors' was not declared. Should it
be static?
symbol 'fsi_slave_handle_error' was not declared. Should it be static?
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reset causes problems for operations requiring multiple scoms (e.g. i2c
over scom). Instead, reset scom engine during probe.
Signed-off-by: Edward A. James <eajames@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Declare bin_attribute structures as const as they are only passed as an
argument to the function device_create_bin_file. This argument is of
type const, so declare the structure as const.
Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
gcc warns about the return type of this function:
drivers/fsi/fsi-core.c:535:8: error: type qualifiers ignored on function return type [-Werror=ignored-qualifiers]
This removes the 'const' attribute, as suggested by the warning.
Fixes: 2b37c3e285 ("drivers/fsi: Set slave SMODE to init communication")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When testing an i2c driver that is a fsi bus driver, I saw the following
oops:
kernel BUG at drivers/base/driver.c:153!
Internal error: Oops - BUG: 0 [#1] ARM
[<8027cb1c>] (driver_register) from [<80344e88>] (fsi_driver_register+0x2c/0x38)
[<80344e88>] (fsi_driver_register) from [<805f5ebc>] (fsi_i2c_driver_init+0x1c/0x24)
[<805f5ebc>] (fsi_i2c_driver_init) from [<805d1f14>] (do_one_initcall+0xb4/0x170)
[<805d1f14>] (do_one_initcall) from [<805d20f0>] (kernel_init_freeable+0x120/0x1dc)
[<805d20f0>] (kernel_init_freeable) from [<8043f4a8>] (kernel_init+0x18/0x104)
[<8043f4a8>] (kernel_init) from [<8000a5e8>] (ret_from_fork+0x14/0x2c)
This is because the fsi bus had not been registered. This fix registers the bus
with postcore_initcall instead, to ensure it is registered earlier on.
When the fsi core is used as a module this should not be a problem as the fsi
driver will depend on the fsi bus type symbol, and will therefore load the core
before the driver.
Fixes: 0508ad1fff ("drivers/fsi: Add empty fsi bus definitions")
Signed-off-by: Joel Stanley <joel@jms.id.au>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For slaves that are behind a software-clocked master, we want FSI CFAMs
to run asynchronously to the FSI clock, so set up our slaves to be in
async mode.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add an engine driver to expose a "hub" FSI master - which has a set of
control registers in the engine address space, and uses a chunk of the
slave address space for actual FSI communication.
Additional changes from Jeremy Kerr <jk@ozlabs.org>.
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Create a simple SCOM engine device driver that reads and writes
its control registers via an FSI bus.
Includes changes from Edward A. James <eajames@us.ibm.com>.
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Edward A. James <eajames@us.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Implement a FSI master using GPIO. Will generate FSI protocol for
read and write commands to particular addresses. Sends master command
and waits for and decodes a slave response.
Includes changes from Edward A. James <eajames@us.ibm.com> and Jeremy
Kerr <jk@ozlabs.org>.
Signed-off-by: Edward A. James <eajames@us.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This change implements error handling in the FSI core, by cleaining up
and retrying failed operations, using the SISC, TERM and BREAK
facilities.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Trace low level read and write FSI bus operations.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Allow drivers to access the slave address ranges.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This change adds a 'raw' file for reads & writes, and a 'term' file for
the TERM command, and a 'break' file for issuing a BREAK.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add driver_register and driver_unregister wrappers for FSI.
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Allow a master to undo a previous scan. Should a master scan a bus
twice it will need to ensure it doesn't double register any
previously detected device.
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
----
v7 - Unscan when unregistering master
- Remove leading '__'s from function names
- Return fail state for sysfs rescan file
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This change introduces the fsi device API: simple read, write and peek
accessors for the devices' address spaces.
Includes contributions from Christopher Bostic
<cbostic@linux.vnet.ibm.com> and Edward A. James <eajames@us.ibm.com>.
Signed-off-by: Edward A. James <eajames@us.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that we have fsi_slave devices, scan each for endpoints, and
register them on the fsi bus.
Includes contributions from Christopher Bostic
<cbostic@linux.vnet.ibm.com>.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Set CFAM to appropriate ID so that the controlling master can manage
link memory ranges. Add slave engine register definitions.
Includes changes from Jeremy Kerr <jk@ozlabs.org>.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Implement fsi_slave_init: if we can read a chip ID, create fsi_slave
devices and register with the driver core.
Includes changes from Christopher Bostic <cbostic@linux.vnet.ibm.com>.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Enable each link and send a break command, and try to detect a slave by
reading from the SMODE register.
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Introduce functions to perform reads/writes on the slave address space;
these simply pass the request on the slave's master with the correct
link and slave ID.
We implement these on top of similar helpers for the master.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Chris Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When a new fsi master is added, we will need to scan its links, and
slaves attached to those links. This change introduces a little shell to
iterate the links, which we will populate with the actual slave scan in
a later change.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Chris Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add the initial fsi slave device, which is private to the core code.
This will be a child of the master, and parent to endpoint devices.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Chris Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add a `struct fsi_master` to represent a FSI master controller.
FSI master drivers register one of these structs to provide
device-specific of the standard operations: read/write/term/break and
link control.
Includes changes from Edward A. James <eajames@us.ibm.com> & Jeremy Kerr
<jk@ozlabs.org>.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Chris Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Driver bind to devices based on the engine types & (optional) versions.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Chris Bostic <cbostic@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This change adds the initial (empty) fsi bus definition, and introduces
drivers/fsi/.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Chris Bostic <cbostic@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Jeremy Kerr
Benjamin Herrenschmidt
Andrew Jeffery
Christopher Bostic
Eddie James
Vincent Legoll
Colin Ian King
Bhumika Goyal
Arnd Bergmann
Joel Stanley