linux-toradex.git/drivers/watchdog/watchdog_dev.c, branch v5.18

watchdog: Improve watchdog_dev function documentation

2022-03-27T15:04:08+00:00

Adjust function comments to the kernel doc format. It
also adjusts some variable names and adds return values.

No functional change.

Changes from V1:
  Change "Returns" to "Return:" (Randy Dunlap)

Cc: Wim Van Sebroeck 
Cc: Guenter Roeck 
Cc: Randy Dunlap 
Cc: linux-watchdog@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira 
Tested-by: Randy Dunlap 
Acked-by: Randy Dunlap 
Reviewed-by: Guenter Roeck 
Link: https://lore.kernel.org/r/30378a03e9cd9b5f6e92ec9bf512edc38bad8627.1644589712.git.bristot@kernel.org
Signed-off-by: Guenter Roeck 
Signed-off-by: Wim Van Sebroeck

watchdog: Start watchdog in watchdog_set_last_hw_keepalive only if appropriate

2021-08-22T08:28:12+00:00

We must not pet a running watchdog when handle_boot_enabled is off
because this will kick off automatic triggering before userland is
running, defeating the purpose of the handle_boot_enabled control.
Furthermore, don't ping in case watchdog_set_last_hw_keepalive was
called incorrectly when the hardware watchdog is actually not running.

Fixed: cef9572e9af3 ("watchdog: add support for adjusting last known HW keepalive time")
Signed-off-by: Jan Kiszka 
Reviewed-by: Guenter Roeck 
Link: https://lore.kernel.org/r/93d56386-6e37-060b-55ce-84de8cde535f@web.de
Signed-off-by: Guenter Roeck 
Signed-off-by: Wim Van Sebroeck

watchdog: introduce watchdog_dev_suspend/resume

2021-08-22T08:28:08+00:00

The watchdog drivers often disable wdog clock during suspend and then
enable it again during resume. Nevertheless the ping worker is still
running and can issue low-level ping while the wdog clock is disabled
causing the system hang. To prevent such condition register pm notifier
in the watchdog core which will call watchdog_dev_suspend/resume and
actually cancel ping worker during suspend and restore it back, if
needed, during resume.

Signed-off-by: Grzegorz Jaszczyk 
Reviewed-by: Guenter Roeck 
Link: https://lore.kernel.org/r/20210618195033.3209598-2-grzegorz.jaszczyk@linaro.org
Signed-off-by: Guenter Roeck 
Signed-off-by: Wim Van Sebroeck

watchdog: Fix NULL pointer dereference when releasing cdev

2021-08-22T08:28:07+00:00

watchdog_hrtimer_pretimeout_stop needs the watchdog device to have a
valid pointer to the watchdog core data to stop the pretimeout hrtimer.
Therefore it needs to be called before the pointers are cleared in
watchdog_cdev_unregister.

Fixes: 7b7d2fdc8c3e ("watchdog: Add hrtimer-based pretimeout feature")
Reported-by: Colin Ian King 
Signed-off-by: Curtis Klein 
Reviewed-by: Guenter Roeck 
Link: https://lore.kernel.org/r/1624429583-5720-1-git-send-email-curtis.klein@hpe.com
Signed-off-by: Guenter Roeck 
Signed-off-by: Wim Van Sebroeck

watchdog: only run driver set_pretimeout op if device supports it

2021-08-22T08:28:07+00:00

Some watchdog devices might conditionally support pretimeouts (e.g. if
an interrupt is exposed for the device) but some watchdog drivers might
still define the set_pretimeout operation (e.g. the mtk_wdt driver) and
indicate support at runtime through the WDIOF_PRETIMEOUT flag. If the
kernel is compiled with CONFIG_WATCHDOG_HRTIMER_PRETIMEOUT enabled,
watchdog_set_pretimeout would run the driver specific set_pretimeout
even if WDIOF_PRETIMEOUT is not set which might have unintended
consequences.

So this change checks that the device flags and only runs the driver
operation if pretimeouts are supported.

Signed-off-by: Curtis Klein 
Reviewed-by: Guenter Roeck 
Link: https://lore.kernel.org/r/1624751265-24785-1-git-send-email-curtis.klein@hpe.com
Signed-off-by: Guenter Roeck 
Signed-off-by: Wim Van Sebroeck

watchdog: Add hrtimer-based pretimeout feature

2021-06-21T06:49:13+00:00

This adds the option to use a hrtimer to generate a watchdog pretimeout
event for hardware watchdogs that do not natively support watchdog
pretimeouts.

With this enabled, all watchdogs will appear to have pretimeout support
in userspace. If no pretimeout value is set, there will be no change in
the watchdog's behavior. If a pretimeout value is set for a specific
watchdog that does not have built-in pretimeout support, a timer will be
started that should fire at the specified time before the watchdog
timeout would occur. When the watchdog is successfully pinged, the timer
will be restarted. If the timer is allowed to fire it will generate a
pretimeout event. However because a software timer is used, it may not
be able to fire in every circumstance.

If the watchdog does support a pretimeout natively, that functionality
will be used instead of the hrtimer.

The general design of this feaure was inspired by the software watchdog,
specifically its own pretimeout implementation. However the software
watchdog and this feature are completely independent. They can be used
together; with or without CONFIG_SOFT_WATCHDOG_PRETIMEOUT enabled.

The main advantage of using the hrtimer pretimeout with a hardware
watchdog, compared to running the software watchdog with a hardware
watchdog, is that if the hardware watchdog driver is unable to ping the
watchdog (e.g. due to a bus or communication error), then the hrtimer
pretimeout would still fire whereas the software watchdog would not.

Signed-off-by: Curtis Klein 
Reviewed-by: Guenter Roeck 
Link: https://lore.kernel.org/r/1612383090-27110-1-git-send-email-curtis.klein@hpe.com
Signed-off-by: Guenter Roeck 
Signed-off-by: Wim Van Sebroeck

watchdog: Use sysfs_emit() and sysfs_emit_at() in "show" functions

2021-06-21T06:49:03+00:00

Convert sprintf() in sysfs "show" functions to sysfs_emit() and
sysfs_emit_at() in order to check for buffer overruns in sysfs outputs.

Signed-off-by: Juerg Haefliger 
Reviewed-by: Guenter Roeck 
Link: https://lore.kernel.org/r/20210511061812.480172-1-juergh@canonical.com
Signed-off-by: Guenter Roeck 
Signed-off-by: Wim Van Sebroeck

watchdog: Add {min,max}_timeout sysfs nodes

2021-06-21T06:49:02+00:00

The valid range for the 'timeout' value is useful information so expose
the min and max timeout values via sysfs.

Signed-off-by: Juerg Haefliger 
Reviewed-by: Guenter Roeck 
Link: https://lore.kernel.org/r/20210511062953.485252-1-juergh@canonical.com
Signed-off-by: Guenter Roeck 
Signed-off-by: Wim Van Sebroeck

watchdog: remove unneeded inclusion of

2020-10-14T13:02:24+00:00

There has been no reference to "struct sched_param" since
commit 94beddacb53c ("sched,watchdog: Convert to sched_set_fifo()"), so
there's no need to include  any more, delete
it.

Signed-off-by: Zhen Lei 
Reviewed-by: Guenter Roeck 
Link: https://lore.kernel.org/r/20200827062154.1847-1-thunder.leizhen@huawei.com
Signed-off-by: Guenter Roeck 
Signed-off-by: Wim Van Sebroeck

watchdog: Use put_device on error

2020-10-14T13:02:24+00:00

We should use put_device() instead of freeing device
directly after device_initialize().

Fixes: cb36e29bb0e4b ("watchdog: initialize device before misc_register")
Signed-off-by: Dinghao Liu 
Reviewed-by: Guenter Roeck 
Link: https://lore.kernel.org/r/20200824031230.31050-1-dinghao.liu@zju.edu.cn
Signed-off-by: Guenter Roeck 
Signed-off-by: Wim Van Sebroeck