Commit graph

27 commits

Author SHA1 Message Date
Andy Shevchenko
2b8cc5858a platform/chrome: cros_ec_spi: Use %*ph for printing hexdump of a small buffer
The kernel already has a helper to print a hexdump of a small
buffer via pointer extension. Use that instead of open coded
variant.

In long term it helps to kill pr_cont() or at least narrow down
its use.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230612212336.4961-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
2023-06-13 12:28:36 +08:00
Brian Norris
015e4b05c3 platform/chrome: cros_ec_spi: Set PROBE_PREFER_ASYNCHRONOUS
This driver often takes on the order of 10ms to start, but in some cases
as much as 600ms [1]. It shouldn't have many cross-device dependencies
to race with, nor racy access to shared state with other drivers, so
this should be a relatively low risk change.

This driver was pinpointed as part of a survey of top slowest initcalls
(i.e., are built in, and probing synchronously) on a lab of ChromeOS
systems.

[1] 600ms was especially surprising to me, so I checked a little deeper.
This driver is used to interface with Embedded Controllers besides just
the traditional laptop power-state controller -- it also interfaces with
some fingerprint readers, which may start up in parallel with the
kernel, or which may not even be present on some SKUs, despite having a
node for it. Thus, our time is wasted just timing out talking to it. At
least we can do that without blocking everyone else.

Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20221101152132.v2.5.Ia458a69e1d592bfa4f04cde7018bbc7486f91a23@changeid
2022-11-02 12:28:47 +08:00
Tzung-Bi Shih
bbd43a37ec platform/chrome: cros_ec_spi: drop BUG_ON() if din isn't large enough
It is overkill to crash the kernel if the `din` buffer is going to full
or overflow.

Drop the BUG_ON() and return -EINVAL instead.

Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Link: https://lore.kernel.org/r/20220513044143.1045728-8-tzungbi@kernel.org
2022-05-16 10:01:52 +08:00
Tzung-Bi Shih
ddec8e9e90 platform/chrome: cros_ec_spi: drop unneeded BUG_ON()
In the context, the following conditions are always false:

- `todo` < 0
Suppose that EC_SPI_FRAME_START is found at the last byte of transfer.

In the case, `ptr` == `end` - 1.  As a result, `todo` must be 0.

- `todo` > `ec_dev->din_size`
Suppose that there is no preamble bytes.  EC_SPI_FRAME_START is found at
the first byte of transfer.

In the case, `end` == `ptr` + EC_MSG_PREAMBLE_COUNT.
As a result, `todo` == EC_MSG_PREAMBLE_COUNT - 1.
However, it already checked `ec_dev->din_size` < EC_MSG_PREAMBLE_COUNT at
the beginning of function.

Drop the unneeded BUG_ON().

Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Link: https://lore.kernel.org/r/20220513044143.1045728-7-tzungbi@kernel.org
2022-05-16 10:01:51 +08:00
Tzung-Bi Shih
71d3ae7fb6 platform/chrome: correct cros_ec_prepare_tx() usage
cros_ec_prepare_tx() returns either:
- >= 0 for number of prepared bytes.
- < 0 for -errno.

Correct the comment and make sure all callers check the return code.

Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20220513044143.1045728-3-tzungbi@kernel.org
2022-05-16 10:01:51 +08:00
Uwe Kleine-König
a0386bba70
spi: make remove callback a void function
The value returned by an spi driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Claudius Heine <ch@denx.de>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC
Acked-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Acked-by: Łukasz Stelmach <l.stelmach@samsung.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220123175201.34839-6-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
2022-02-09 13:00:45 +00:00
Uwe Kleine-König
afb0a80e63
platform/chrome: cros_ec: Make cros_ec_unregister() return void
Up to now cros_ec_unregister() returns zero unconditionally. Make it
return void instead which makes it easier to see in the callers that
there is no error to handle.

Also the return value of i2c, platform and spi remove callbacks is
ignored anyway.

Reviewed-by: Guenter Roeck <groeck@chromium.org>
Link: https://lore.kernel.org/r/20211020071753.wltjslmimb6wtlp5@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220123175201.34839-5-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
2022-02-09 13:00:43 +00:00
Stephen Boyd
7a5172b799
platform/chrome: cros_ec_spi: Drop bits_per_word assignment
This is already handed by default in spi_setup() if the bits_per_word is
0, so just drop it to shave off a line.

Cc: Simon Glass <sjg@chromium.org>
Cc: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Cc: Alexandru M Stan <amstan@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Link: https://lore.kernel.org/r/20201204193540.3047030-3-swboyd@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>
2020-12-09 16:52:09 +00:00
Stephen Boyd
74639cbf51
platform/chrome: cros_ec_spi: Don't overwrite spi::mode
There isn't any need to overwrite the mode here in the driver with what
has been detected by the firmware, such as DT or ACPI. In fact, if we
use the SPI CS gpio descriptor feature we will overwrite the mode with
SPI_MODE_0 where it already contains SPI_MODE_0 and more importantly
SPI_CS_HIGH. Clearing the SPI_CS_HIGH bit causes the CS line to toggle
when the device is probed when it shouldn't change, confusing the driver
and making it fail to probe. Drop the assignment and let the spi core
take care of it.

Fixes: a17d94f0b6 ("mfd: Add ChromeOS EC SPI driver")
Cc: Simon Glass <sjg@chromium.org>
Cc: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Cc: Alexandru M Stan <amstan@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Link: https://lore.kernel.org/r/20201204193540.3047030-2-swboyd@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>
2020-12-09 16:52:08 +00:00
Linus Torvalds
fb893de323 chrome platform changes for 5.9
* cros_ec_typec
 - Add support for switch control and alternate modes to the Chrome EC Type C
   port driver
 - Add basic suspend/resume support
 
 * sensorhub:
 - Fix timestamp overflow issue
 - Fix legacy timestamp spreading on Nami systems
 
 * cros_ec_proto:
 - After removing all users of, stop exporting cros_ec_cmd_xfer
 - Check for missing EC_CMD_HOST_EVENT_GET_WAKE_MASK and ignore wakeups on old
   ECs
 
 * misc:
 - Documentation warning cleanup.
 - Fix double unlock issue in ishtp
 -----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQQCtZK6p/AktxXfkOlzbaomhzOwwgUCXzG3VwAKCRBzbaomhzOw
 wkRMAQCjvqZwbMJ+jNXsgqb5+78WN6i4PC5e7lzjPofHEdE6sAEAm4FiTpcEc/Kk
 qnti54fb3O15I/x8sXWceznXbdFAigw=
 =zFfw
 -----END PGP SIGNATURE-----

Merge tag 'tag-chrome-platform-for-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux

Pull chrome platform updates from Benson Leung:
 "cros_ec_typec:

   - Add support for switch control and alternate modes to the Chrome EC
     Type C port driver

   - Add basic suspend/resume support

  sensorhub:

   - Fix timestamp overflow issue

   - Fix legacy timestamp spreading on Nami systems

  cros_ec_proto:

   - After removing all users of, stop exporting cros_ec_cmd_xfer

   - Check for missing EC_CMD_HOST_EVENT_GET_WAKE_MASK and ignore
     wakeups on old ECs

  misc:

   - Documentation warning cleanup

   - Fix double unlock issue in ishtp"

* tag 'tag-chrome-platform-for-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux: (21 commits)
  platform/chrome: cros_ec_proto: check for missing EC_CMD_HOST_EVENT_GET_WAKE_MASK
  platform/chrome: cros_ec_proto: ignore unnecessary wakeups on old ECs
  platform/chrome: cros_ec_sensorhub: Simplify legacy timestamp spreading
  platform/chrome: cros_ec_proto: Do not export cros_ec_cmd_xfer()
  platform/chrome: cros_ec_typec: Unregister partner on error
  platform/chrome: cros_ec_sensorhub: Fix EC timestamp overflow
  platform/chrome: cros_ec_typec: Add PM support
  platform/chrome: cros_ec_typec: Use workqueue for port update
  platform/chrome: cros_ec_typec: Add a dependency on USB_ROLE_SWITCH
  platform/chrome: cros_ec_ishtp: Fix a double-unlock issue
  platform/chrome: cros_ec_rpmsg: Document missing struct parameters
  platform/chrome: cros_ec_spi: Document missing function parameters
  platform/chrome: cros_ec_typec: Add TBT compat support
  platform/chrome: cros_ec: Add TBT pd_ctrl fields
  platform/chrome: cros_ec_typec: Make configure_mux static
  platform/chrome: cros_ec_typec: Support DP alt mode
  platform/chrome: cros_ec_typec: Add USB mux control
  platform/chrome: cros_ec_typec: Register PD CTRL cmd v2
  platform/chrome: cros_ec: Update mux state bits
  platform/chrome: cros_ec_typec: Register Type C switches
  ...
2020-08-11 17:28:32 -07:00
Enric Balletbo i Serra
3c5ca501b4 platform/chrome: cros_ec_spi: Document missing function parameters
Kerneldoc expects all kernel function members to be documented.

Fixes the following W=1 level warnings:

  cros_ec_spi.c:153: warning: Function parameter or member 'ec_dev' not described in 'receive_n_bytes'
  cros_ec_spi.c:153: warning: Function parameter or member 'buf' not described in 'receive_n_bytes'
  cros_ec_spi.c:153: warning: Function parameter or member 'n' not described in 'receive_n_bytes'

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
2020-06-30 11:41:25 +02:00
Peter Zijlstra
8b700983de sched: Remove sched_set_*() return value
Ingo suggested that since the new sched_set_*() functions are
implemented using the 'nocheck' variants, they really shouldn't ever
fail, so remove the return value.

Cc: axboe@kernel.dk
Cc: daniel.lezcano@linaro.org
Cc: sudeep.holla@arm.com
Cc: airlied@redhat.com
Cc: broonie@kernel.org
Cc: paulmck@kernel.org
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
2020-06-15 14:10:26 +02:00
Peter Zijlstra
3070da3340 sched,spi: Convert to sched_set_fifo*()
Because SCHED_FIFO is a broken scheduler model (see previous patches)
take away the priority field, the kernel can't possibly make an
informed decision.

No effective change.

Cc: broonie@kernel.org
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
2020-06-15 14:10:22 +02:00
Benson Leung
a46387712d
platform/chrome: cros_ec_spi: Wait for USECS, not NSECS
The use of `delay_usecs` in terminate_request() was replaced with the new
`delay` struct used by the SPI subsystem, however the unit was
set to SPI_DELAY_UNIT_NSECS instead of SPI_DELAY_UNIT_USECS. This fixes that.

Fixes: 7d3ca507fd ("platform/chrome: cros_ec_spi: Use new structure for SPI transfer delays")
Signed-off-by: Benson Leung <bleung@chromium.org>
2020-04-07 14:42:08 -07:00
Sergiu Cuciurean
7d3ca507fd platform/chrome: cros_ec_spi: Use new structure for SPI transfer delays
In a recent change to the SPI subsystem [1], a new `delay` struct was added
to replace the `delay_usecs`. This change replaces the current
`delay_usecs` with `delay` for this driver.

The `spi_transfer_delay_exec()` function [in the SPI framework] makes sure
that both `delay_usecs` & `delay` are used (in this order to preserve
backwards compatibility).

[1] commit bebcfd272d ("spi: introduce `delay` field for
`spi_transfer` + spi_transfer_delay_exec()")

Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
2020-03-02 11:04:04 +01:00
Enric Balletbo i Serra
034dbec179 platform/chrome: cros_ec: Match implementation with headers
The 'cros_ec' core driver is the common interface for the cros_ec
transport drivers to do the shared operations to register, unregister,
suspend, resume and handle_event. The interface is provided by including
the header 'include/linux/platform_data/cros_ec_proto.h', however, instead
of have the implementation of these functions in cros_ec_proto.c, it is in
'cros_ec.c', which is a different kernel module. Apart from being a bad
practice, this can induce confusions allowing the users of the cros_ec
protocol to call these functions.

The register, unregister, suspend, resume and handle_event functions
*should* only be called by the different transport drivers (i2c, spi, lpc,
etc.), so make this a bit less confusing by moving these functions from
the public in-kernel space to a private include in platform/chrome, and
then, the interface for cros_ec module and for the cros_ec_proto module is
clean.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Benson Leung <bleung@chromium.org>
2020-02-03 17:14:50 +01:00
Linus Torvalds
32b90daf5c chrome platform changes for v5.4
* CrOS EC / MFD Migration
  - Move cros_ec core driver from mfd into chrome platform.
 
 * Wilco EC:
  - Add batt_ppid_info command to Wilco telemetry driver.
 
 * CrOS EC:
  - cros_ec_rpmsg : Add support to inform EC of suspend/resume status
  - cros_ec_rpmsg : Fix race condition on probe failed
  - cros_ec_chardev : Add a poll handler to receive MKBP events
 
 * Misc:
  - bugfixes in cros_usbpd_logger and cros_ec_ishtp
 -----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQQCtZK6p/AktxXfkOlzbaomhzOwwgUCXYKpygAKCRBzbaomhzOw
 wlkXAP9QCKia7LiNujIl9kh7WXSloxdO0BzL93pgSpNHfUDeSAD+Mlcp+54bDqkB
 WaF2SR14Z2vzAFafroQTl6m41xJTog4=
 =slD7
 -----END PGP SIGNATURE-----

Merge tag 'tag-chrome-platform-for-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux

Pull chrome platform updates from Benson Leung:
 "CrOS EC / MFD Migration:
    - Move cros_ec core driver from mfd into chrome platform.

  Wilco EC:
    - Add batt_ppid_info command to Wilco telemetry driver.

  CrOS EC:
    - cros_ec_rpmsg : Add support to inform EC of suspend/resume status
    - cros_ec_rpmsg : Fix race condition on probe failed
    - cros_ec_chardev : Add a poll handler to receive MKBP events

  Misc:
    - bugfixes in cros_usbpd_logger and cros_ec_ishtp"

* tag 'tag-chrome-platform-for-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux:
  platform/chrome: cros_usbpd_logger: null check create_singlethread_workqueue
  platform/chrome: cros_ec_chardev: Add a poll handler to receive MKBP events
  platform/chrome: cros_ec_rpmsg: Fix race with host command when probe failed
  platform/chrome: chromeos_tbmc: Report wake events
  mfd: cros_ec: Use mfd_add_hotplug_devices() helper
  mfd: cros_ec: Add convenience struct to define autodetectable CrOS EC subdevices
  mfd: cros_ec: Add convenience struct to define dedicated CrOS EC MCUs
  mfd: cros_ec: Use kzalloc and cros_ec_cmd_xfer_status helper
  mfd / platform: cros_ec: Reorganize platform and mfd includes
  mfd / platform: cros_ec: Rename config to a better name
  mfd: cros_ec: Switch to use the new cros-ec-chardev driver
  mfd / platform: cros_ec: Miscellaneous character device to talk with the EC
  mfd / platform: cros_ec: Move cros-ec core driver out from MFD
  mfd / platform: cros_ec: Handle chained ECs as platform devices
  platform/chrome: cros_ec_rpmsg: Add host command AP sleep state support
  platform/chrome: chromeos_laptop: drop checks of NULL-safe functions
  platform/chrome: wilco_ec: Add batt_ppid_info command to telemetry driver
2019-09-19 14:14:28 -07:00
Enric Balletbo i Serra
840d9f131f mfd / platform: cros_ec: Reorganize platform and mfd includes
There is a bit of mess between cros-ec mfd includes and platform
includes. For example, we have a linux/mfd/cros_ec.h include that
exports the interface implemented in platform/chrome/cros_ec_proto.c. Or
we have a linux/mfd/cros_ec_commands.h file that is non related to the
multifunction device (in the sense that is not exporting any function of
the mfd device). This causes crossed includes between mfd and
platform/chrome subsystems and makes the code difficult to read, apart
from creating 'curious' situations where a platform/chrome driver includes
a linux/mfd/cros_ec.h file just to get the exported functions that are
implemented in another platform/chrome driver.

In order to have a better separation on what the cros-ec multifunction
driver does and what the cros-ec core provides move and rework the
affected includes doing:

 - Move cros_ec_commands.h to include/linux/platform_data/cros_ec_commands.h
 - Get rid of the parts that are implemented in the platform/chrome/cros_ec_proto.c
   driver from include/linux/mfd/cros_ec.h to a new file
   include/linux/platform_data/cros_ec_proto.h
 - Update all the drivers with the new includes, so
   - Drivers that only need to know about the protocol include
     - linux/platform_data/cros_ec_proto.h
     - linux/platform_data/cros_ec_commands.h
   - Drivers that need to know about the cros-ec mfd device also include
     - linux/mfd/cros_ec.h

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Tested-by: Gwendal Grignou <gwendal@chromium.org>
Series changes: 3
- Fix dereferencing pointer to incomplete type 'struct cros_ec_dev' (lkp)
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-09-02 11:33:42 +01:00
Enric Balletbo i Serra
7aa703bb88 mfd / platform: cros_ec: Handle chained ECs as platform devices
An MFD is a device that contains several sub-devices (cells). For instance,
the ChromeOS EC fits in this description as usually contains a charger and
can have other devices with different functions like a Real-Time Clock,
an Audio codec, a Real-Time Clock, ...

If you look at the driver, though, we're doing something odd. We have
two MFD cros-ec drivers where one of them (cros-ec-core) instantiates
another MFD driver as sub-driver (cros-ec-dev), and the latest
instantiates the different sub-devices (Real-Time Clock, Audio codec,
etc).

                  MFD
------------------------------------------
   cros-ec-core
       |___ mfd-cellA (cros-ec-dev)
       |       |__ mfd-cell0
       |       |__ mfd-cell1
       |       |__ ...
       |
       |___ mfd-cellB (cros-ec-dev)
               |__ mfd-cell0
               |__ mfd-cell1
               |__ ...

The problem that was trying to solve is to describe some kind of topology for
the case where we have an EC (cros-ec) chained with another EC
(cros-pd). Apart from that this extends the bounds of what MFD was
designed to do we might be interested on have other kinds of topology that
can't be implemented in that way.

Let's prepare the code to move the cros-ec-core part from MFD to
platform/chrome as this is clearly a platform specific thing non-related
to a MFD device.

  platform/chrome  |         MFD
------------------------------------------
                   |
   cros-ec ________|___ cros-ec-dev
                   |       |__ mfd-cell0
                   |       |__ mfd-cell1
                   |       |__ ...
                   |
   cros-pd ________|___ cros-ec-dev
                   |        |__ mfd-cell0
                   |        |__ mfd-cell1
                   |        |__ ...

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Tested-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-09-02 11:32:57 +01:00
Peter Zijlstra
4ff13d00eb
spi: Reduce kthread priority
The SPI thingies request FIFO-99 by default, reduce this to FIFO-50.

FIFO-99 is the very highest priority available to SCHED_FIFO and
it not a suitable default; it would indicate the SPI work is the
most important work on the machine.

Cc: Benson Leung <bleung@chromium.org>
Cc: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: linux-spi@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20190801111541.917256884@infradead.org
Signed-off-by: Mark Brown <broonie@kernel.org>
2019-08-02 12:15:24 +01:00
Douglas Anderson
ac5bdfdc0e platform/chrome: cros_ec_spi: Request the SPI thread be realtime
All currently known ECs in the wild are very sensitive to timing.
Specifically the ECs are known to drop a transfer if more than 8 ms
passes from the assertion of the chip select until the transfer
finishes.

Let's use the new feature introduced in the patch (spi: Allow SPI
devices to request the pumping thread be realtime") to request the SPI
pumping thread be realtime.  This means that if we get shunted off to
the SPI thread for whatever reason we won't get downgraded to low
priority.

NOTES:
- We still need to keep ourselves as high priority since the SPI core
  doesn't guarantee that all transfers end up on the pumping thread
  (in fact, it tries pretty hard to do them in the calling context).
- If future Chrome OS ECs ever fix themselves to be less sensitive
  then we could consider adding a property (or compatible string) to
  not set this property.  For now we need it across the board.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
2019-05-24 11:35:30 +02:00
Douglas Anderson
7dadf88f8d platform/chrome: cros_ec_spi: Move to real time priority for transfers
In commit 37a186225a ("platform/chrome: cros_ec_spi: Transfer
messages at high priority") we moved transfers to a high priority
workqueue.  This helped make them much more reliable.

...but, we still saw failures.

We were actually finding ourselves competing for time with dm-crypt
which also scheduled work on HIGHPRI workqueues.  While we can
consider reverting the change that made dm-crypt run its work at
HIGHPRI, the argument in commit a1b89132dc ("dm crypt: use
WQ_HIGHPRI for the IO and crypt workqueues") is somewhat compelling.
It does make sense for IO to be scheduled at a priority that's higher
than the default user priority.  It also turns out that dm-crypt isn't
alone in using high priority like this.  loop_prepare_queue() does
something similar for loopback devices.

Looking in more detail, it can be seen that the high priority
workqueue isn't actually that high of a priority.  It runs at MIN_NICE
which is _fairly_ high priority but still below all real time
priority.

Should we move cros_ec_spi to real time priority to fix our problems,
or is this just escalating a priority war?  I'll argue here that
cros_ec_spi _does_ belong at real time priority.  Specifically
cros_ec_spi actually needs to run quickly for correctness.  As I
understand this is exactly what real time priority is for.

There currently doesn't appear to be any way to use the standard
workqueue APIs with a real time priority, so we'll switch over to
using using a kthread worker.  We'll match the priority that the SPI
core uses when it wants to do things on a realtime thread and just use
"MAX_RT_PRIO - 1".

This commit plus the patch ("platform/chrome: cros_ec_spi: Request the
SPI thread be realtime") are enough to get communications very close
to 100% reliable (the only known problem left is when serial console
is turned on, which isn't something that happens in shipping devices).
Specifically this test case now passes (tested on rk3288-veyron-jerry):

  dd if=/dev/zero of=/var/log/foo.txt bs=4M count=512&
  while true; do
    ectool version > /dev/null;
  done

It should be noted that "/var/log" is encrypted (and goes through
dm-crypt) and also passes through a loopback device.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
2019-05-20 23:45:24 +02:00
Evan Green
75501d2edc platform/chrome: cros_ec_spi: Always add of_match_table
The Chrome OS EC driver attaches to devices using the of_match_table
even when ACPI is the underlying firmware. It does this using the
magic PRP0001 ACPI HID, which tells ACPI to go find an OF compatible
string under the hood and match on that.

The cros_ec_spi driver needs to provide the of_match_table regardless
of whether CONFIG_OF is enabled or not, since the table is used by
ACPI for PRP0001 devices.

Signed-off-by: Evan Green <evgreen@chromium.org>
Reviewed-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
2019-05-20 10:18:10 +02:00
Douglas Anderson
37a186225a platform/chrome: cros_ec_spi: Transfer messages at high priority
The software running on the Chrome OS Embedded Controller (cros_ec)
handles SPI transfers in a bit of a wonky way.  Specifically if the EC
sees too long of a delay in a SPI transfer it will give up and the
transfer will be counted as failed.  Unfortunately the timeout is
fairly short, though the actual number may be different for different
EC codebases.

We can end up tripping the timeout pretty easily if we happen to
preempt the task running the SPI transfer and don't get back to it for
a little while.

Historically this hasn't been a _huge_ deal because:
1. On old devices Chrome OS used to run PREEMPT_VOLUNTARY.  That meant
   we were pretty unlikely to take a big break from the transfer.
2. On recent devices we had faster / more processors.
3. Recent devices didn't use "cros-ec-spi-pre-delay".  Using that
   delay makes us more likely to trip this use case.
4. For whatever reasons (I didn't dig) old kernels seem to be less
   likely to trip this.
5. For the most part it's kinda OK if a few transfers to the EC fail.
   Mostly we're just polling the battery or doing some other task
   where we'll try again.

Even with the above things, this issue has reared its ugly head
periodically.  We could solve this in a nice way by adding reliable
retries to the EC protocol [1] or by re-designing the code in the EC
codebase to allow it to wait longer, but that code doesn't ever seem
to get changed.  ...and even if it did, it wouldn't help old devices.

It's now time to finally take a crack at making this a little better.
This patch isn't guaranteed to make every cros_ec SPI transfer
perfect, but it should improve things by a few orders of magnitude.
Specifically you can try this on a rk3288-veyron Chromebook (which is
slower and also _does_ need "cros-ec-spi-pre-delay"):
  md5sum /dev/zero &
  md5sum /dev/zero &
  md5sum /dev/zero &
  md5sum /dev/zero &
  while true; do
    cat /sys/class/power_supply/sbs-20-000b/charge_now > /dev/null;
  done
...before this patch you'll see boatloads of errors.  After this patch I
don't see any in the testing I did.

The way this patch works is by effectively boosting the priority of
the cros_ec transfers.  As far as I know there is no simple way to
just boost the priority of the current process temporarily so the way
we accomplish this is by queuing the work on the system_highpri_wq.

NOTE: this patch relies on the fact that the SPI framework attempts to
push the messages out on the calling context (which is the one that is
boosted to high priority).  As I understand from earlier (long ago)
discussions with Mark Brown this should be a fine assumption.  Even if
it isn't true sometimes this patch will still not make things worse.

[1] https://crbug.com/678675

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
2019-04-15 12:13:24 +02:00
Enric Balletbo i Serra
30fc9147ae platform/chrome: cros_ec_spi: switch to SPDX identifier
Adopt the SPDX license identifier headers to ease license compliance
management. Also change the description for one more appropriate.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
2019-02-01 10:13:06 +01:00
Enric Balletbo i Serra
4bc59c2f7e mfd / platform: cros_ec: Use devm_mfd_add_devices
Use devm_mfd_add_devices() for adding cros-ec core MFD child devices. This
reduces the need of remove callback from platform/chrome for removing the
MFD child devices.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-02-01 08:09:27 +00:00
Enric Balletbo i Serra
d00a8741fd
platform/chrome: Move cros-ec transport drivers to drivers/platform.
There are some cros-ec transport drivers (I2C, SPI) living in MFD, while
others (LPC) living in drivers/platform. The transport drivers are more
platform specific. So, move the I2C and SPI transport drivers to the
platform/chrome directory. The patch also removes the MFD_ prefix of
their Kconfig symbols.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Benson Leung <bleung@chromium.org>
2018-07-03 12:40:06 -07:00
Renamed from drivers/mfd/cros_ec_spi.c (Browse further)