diff options
| author | Damien Riegel <damien.riegel@savoirfairelinux.com> | 2015-11-16 12:27:59 -0500 |
|---|---|---|
| committer | Wim Van Sebroeck <wim@iguana.be> | 2015-12-13 15:27:10 +0100 |
| commit | 2165bf524da5f5e496d1cdb8c5afae1345ecce1e (patch) | |
| tree | 75a24ea774d08021e1c45e201ffc9f7a164ca661 /Documentation/watchdog | |
| parent | 1f32f83e5d81c1e99a1c16366e71d5867cd1e364 (diff) | |
watchdog: core: add restart handler support
Many watchdog drivers implement the same code to register a restart
handler. This patch provides a generic way to set such a function.
The patch adds a new restart watchdog operation. If a restart priority
greater than 0 is needed, the driver can call
watchdog_set_restart_priority to set it.
Suggested-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Diffstat (limited to 'Documentation/watchdog')
| -rw-r--r-- | Documentation/watchdog/watchdog-kernel-api.txt | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt index d8b0d3367706..dbc6a65f0bd1 100644 --- a/Documentation/watchdog/watchdog-kernel-api.txt +++ b/Documentation/watchdog/watchdog-kernel-api.txt @@ -53,6 +53,7 @@ struct watchdog_device { unsigned int timeout; unsigned int min_timeout; unsigned int max_timeout; + struct notifier_block restart_nb; void *driver_data; struct mutex lock; unsigned long status; @@ -75,6 +76,10 @@ It contains following fields: * timeout: the watchdog timer's timeout value (in seconds). * min_timeout: the watchdog timer's minimum timeout value (in seconds). * max_timeout: the watchdog timer's maximum timeout value (in seconds). +* restart_nb: notifier block that is registered for machine restart, for + internal use only. If a watchdog is capable of restarting the machine, it + should define ops->restart. Priority can be changed through + watchdog_set_restart_priority. * bootstatus: status of the device after booting (reported with watchdog WDIOF_* status bits). * driver_data: a pointer to the drivers private data of a watchdog device. @@ -100,6 +105,7 @@ struct watchdog_ops { unsigned int (*status)(struct watchdog_device *); int (*set_timeout)(struct watchdog_device *, unsigned int); unsigned int (*get_timeleft)(struct watchdog_device *); + int (*restart)(struct watchdog_device *); void (*ref)(struct watchdog_device *); void (*unref)(struct watchdog_device *); long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long); @@ -164,6 +170,8 @@ they are supported. These optional routines/operations are: (Note: the WDIOF_SETTIMEOUT needs to be set in the options field of the watchdog's info structure). * get_timeleft: this routines returns the time that's left before a reset. +* restart: this routine restarts the machine. It returns 0 on success or a + negative errno code for failure. * ref: the operation that calls kref_get on the kref of a dynamically allocated watchdog_device struct. * unref: the operation that calls kref_put on the kref of a dynamically @@ -231,3 +239,14 @@ the device tree (if the module timeout parameter is invalid). Best practice is to set the default timeout value as timeout value in the watchdog_device and then use this function to set the user "preferred" timeout value. This routine returns zero on success and a negative errno code for failure. + +To change the priority of the restart handler the following helper should be +used: + +void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority); + +User should follow the following guidelines for setting the priority: +* 0: should be called in last resort, has limited restart capabilities +* 128: default restart handler, use if no other handler is expected to be + available, and/or if restart is sufficient to restart the entire system +* 255: highest priority, will preempt all other restart handlers |