linux-stable.git/drivers/platform/chrome/cros_ec_debugfs.c, branch linux-6.2.y

platform/chrome: cros_ec_debugfs: Set PROBE_PREFER_ASYNCHRONOUS

2022-11-02T04:28:47+00:00

This driver takes on the order of 40ms to start on some systems. 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.

Signed-off-by: Brian Norris 
Signed-off-by: Tzung-Bi Shih 
Link: https://lore.kernel.org/r/20221101152132.v2.3.Ic9a4f378f73319da323cd55940012fa6b1de24f4@changeid

platform/chrome: cros_ec: Expose suspend_timeout_ms in debugfs

2022-08-24T02:37:07+00:00

In modern Chromebooks, the embedded controller has a mechanism where
it will watch a hardware-controlled line that toggles in suspend, and
wake the system up if an expected sleep transition didn't occur. This
can be very useful for detecting power management issues where the
system appears to suspend, but doesn't actually reach its lowest
expected power states.

Sometimes it's useful in debug and test scenarios to be able to control
the duration of that timeout, or even disable the EC timeout mechanism
altogether. Add a debugfs control to set the timeout to values other
than the EC-defined default, for more convenient debug and
development iteration.

Signed-off-by: Evan Green 
Reviewed-by: Prashant Malani 
Reviewed-by: Stephen Boyd 
Reviewed-by: Guenter Roeck 
Link: https://lore.kernel.org/r/20220822144026.v3.1.Idd188ff3f9caddebc17ac357a13005f93333c21f@changeid
[tzungbi: fix one nit in Documentation/ABI/testing/debugfs-cros-ec.]
Signed-off-by: Tzung-Bi Shih

platform/chrome: cros_ec_debugfs: detach log reader wq from devm

2022-03-31T23:56:48+00:00

Debugfs console_log uses devm memory (e.g. debug_info in
cros_ec_console_log_poll()).  However, lifecycles of device and debugfs
are independent.  An use-after-free issue is observed if userland
program operates the debugfs after the memory has been freed.

The call trace:
 do_raw_spin_lock
 _raw_spin_lock_irqsave
 remove_wait_queue
 ep_unregister_pollwait
 ep_remove
 do_epoll_ctl

A Python example to reproduce the issue:
... import select
... p = select.epoll()
... f = open('/sys/kernel/debug/cros_scp/console_log')
... p.register(f, select.POLLIN)
... p.poll(1)
[(4, 1)]                    # 4=fd, 1=select.POLLIN

[ shutdown cros_scp at the point ]

... p.poll(1)
[(4, 16)]                   # 4=fd, 16=select.POLLHUP
... p.unregister(f)

An use-after-free issue raises here.  It called epoll_ctl with
EPOLL_CTL_DEL which in turn to use the workqueue in the devm (i.e.
log_wq).

Detaches log reader's workqueue from devm to make sure it is persistent
even if the device has been removed.

Signed-off-by: Tzung-Bi Shih 
Reviewed-by: Guenter Roeck 
Link: https://lore.kernel.org/r/20220209051130.386175-1-tzungbi@google.com
Signed-off-by: Benson Leung

platform/chrome: cros_ec_debugfs: Control uptime information request

2020-06-19T17:16:18+00:00

When EC does not support uptime command (EC_CMD_GET_UPTIME_INFO),
do not create the uptime sysfs entry point.
User space application will not probe the file needlessly.

The EC console log will not contain EC_CMD_GET_UPTIME_INFO anymore.

Signed-off-by: Gwendal Grignou 
Signed-off-by: Enric Balletbo i Serra

cros_ec: treewide: Remove 'include/linux/mfd/cros_ec.h'

2020-01-07T16:36:46+00:00

This header file now only includes the cros_ec_dev struct, however, is the
'include/linux/platform_data/cros_ec_proto.h' who contains the definition of
all the Chrome OS EC related structs. There is no reason to have a
separate include for this struct so move to the place where other
structs are defined. That way, we can remove the include itself, but also
simplify the common pattern

    #include 
    #include 

for a single include

    #include 

The changes to remove the cros_ec.h include were generated with the
following shell script:

    git grep -l "" | xargs sed -i '//d'

Signed-off-by: Enric Balletbo i Serra 
Acked-by: Lee Jones 
Acked-by: Alexandre Belloni 
Acked-by: Jonathan Cameron 
Acked-by: Sebastian Reichel 
Acked-by: Hans Verkuil

mfd / platform: cros_ec: Reorganize platform and mfd includes

2019-09-02T10:33:42+00:00

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 
Acked-by: Andy Shevchenko 
Acked-by: Mark Brown 
Acked-by: Wolfram Sang 
Acked-by: Neil Armstrong 
Acked-by: Alexandre Belloni 
Acked-by: Jonathan Cameron 
Acked-by: Benjamin Tissoires 
Acked-by: Dmitry Torokhov 
Acked-by: Sebastian Reichel 
Acked-by: Chanwoo Choi 
Reviewed-by: Gwendal Grignou 
Tested-by: Gwendal Grignou 
Series changes: 3
- Fix dereferencing pointer to incomplete type 'struct cros_ec_dev' (lkp)
Signed-off-by: Lee Jones

mfd / platform: cros_ec_debugfs: Expose resume result via debugfs

2019-07-01T13:39:11+00:00

For ECs that support it, the EC returns the number of slp_s0
transitions and whether or not there was a timeout in the resume
response. Expose the last resume result to usermode via debugfs so
that usermode can detect and report S0ix timeouts.

Signed-off-by: Evan Green 
Acked-by: Lee Jones 
Signed-off-by: Enric Balletbo i Serra

platform/chrome: cros_ec_debugfs: cros_ec_uptime_fops can be static

2019-06-18T08:32:31+00:00

Fixes: 909447f683b3 ("platform/chrome: cros_ec_debugfs: Add debugfs entry to retrieve EC uptime")
Signed-off-by: kbuild test robot 
Signed-off-by: Enric Balletbo i Serra

platform/chrome: cros_ec_debugfs: Fix kernel-doc comment first line

2019-06-18T08:07:54+00:00

kernel-doc comments have a prescribed format. To be _particularly_
correct we should also capitalise the brief description and terminate
it with a period.

Signed-off-by: Enric Balletbo i Serra

platform/chrome: cros_ec_debugfs: Add debugfs entry to retrieve EC uptime

2019-06-18T08:07:13+00:00

The new debugfs entry 'uptime' is being made available to userspace so that
a userspace daemon can synchronize EC logs with host time.

Signed-off-by: Tim Wawrzynczak 
[rework based on Tim's first approach]
Signed-off-by: Enric Balletbo i Serra 
Tested-by: Tim Wawrzynczak