diff options
| author |  Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
| 2021-06-18 21:50:32 +0200 |
|---|---|---|
| committer |  Wim Van Sebroeck <wim@linux-watchdog.org>
| 2021-08-22 10:28:08 +0200 |
| commit | 60bcd91aafd22ef62cef9ae2037fa2e1d4da2fb3 (patch) | |
| tree | 918b076b7d7ab529aa5f26f101864a6505ad4802 /drivers/watchdog/watchdog_dev.c | |
| parent | watchdog: Fix NULL pointer dereference when releasing cdev (diff) | |
| download | linux-60bcd91aafd22ef62cef9ae2037fa2e1d4da2fb3.tar.gz linux-60bcd91aafd22ef62cef9ae2037fa2e1d4da2fb3.tar.bz2 linux-60bcd91aafd22ef62cef9ae2037fa2e1d4da2fb3.zip | |
watchdog: introduce watchdog_dev_suspend/resume
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 <grzegorz.jaszczyk@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210618195033.3209598-2-grzegorz.jaszczyk@linaro.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Diffstat (limited to 'drivers/watchdog/watchdog_dev.c')
| -rw-r--r-- | drivers/watchdog/watchdog_dev.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index f408967ff1a4..597cf16ea4ba 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -1228,6 +1228,53 @@ void __exit watchdog_dev_exit(void) kthread_destroy_worker(watchdog_kworker); } +int watchdog_dev_suspend(struct watchdog_device *wdd) +{ + struct watchdog_core_data *wd_data = wdd->wd_data; + int ret = 0; + + if (!wdd->wd_data) + return -ENODEV; + + /* ping for the last time before suspend */ + mutex_lock(&wd_data->lock); + if (watchdog_worker_should_ping(wd_data)) + ret = __watchdog_ping(wd_data->wdd); + mutex_unlock(&wd_data->lock); + + if (ret) + return ret; + + /* + * make sure that watchdog worker will not kick in when the wdog is + * suspended + */ + hrtimer_cancel(&wd_data->timer); + kthread_cancel_work_sync(&wd_data->work); + + return 0; +} + +int watchdog_dev_resume(struct watchdog_device *wdd) +{ + struct watchdog_core_data *wd_data = wdd->wd_data; + int ret = 0; + + if (!wdd->wd_data) + return -ENODEV; + + /* + * __watchdog_ping will also retrigger hrtimer and therefore restore the + * ping worker if needed. + */ + mutex_lock(&wd_data->lock); + if (watchdog_worker_should_ping(wd_data)) + ret = __watchdog_ping(wd_data->wdd); + mutex_unlock(&wd_data->lock); + + return ret; +} + module_param(handle_boot_enabled, bool, 0444); MODULE_PARM_DESC(handle_boot_enabled, "Watchdog core auto-updates boot enabled watchdogs before userspace takes over (default=" |