watchdog: core: add reboot notifier support
Many watchdog drivers register a reboot notifier in order to stop the
watchdog on system reboot. Thus we can factorize this code in the
watchdog core.
For that purpose, a new notifier block is added in watchdog_device for
internal use only, as well as a new watchdog_stop_on_reboot helper
function.
If this helper is called, watchdog core registers the related notifier
block and will stop the watchdog when SYS_HALT or SYS_DOWN is received.
Since this operation can be critical on some platforms, abort the device
registration if the reboot notifier registration fails.
Suggested-by: Vivien Didelot <[email protected]>
Signed-off-by: Damien Riegel <[email protected]>
Reviewed-by: Vivien Didelot <[email protected]>
Signed-off-by: Guenter Roeck <[email protected]>
Signed-off-by: Wim Van Sebroeck <[email protected]>
diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h
index 5b52c83..a88f955 100644
--- a/include/linux/watchdog.h
+++ b/include/linux/watchdog.h
@@ -65,6 +65,7 @@
* @timeout: The watchdog devices timeout value (in seconds).
* @min_timeout:The watchdog devices minimum timeout value (in seconds).
* @max_timeout:The watchdog devices maximum timeout value (in seconds).
+ * @reboot_nb: The notifier block to stop watchdog on reboot.
* @restart_nb: The notifier block to register a restart function.
* @driver-data:Pointer to the drivers private data.
* @lock: Lock for watchdog core internal use only.
@@ -92,6 +93,7 @@
unsigned int timeout;
unsigned int min_timeout;
unsigned int max_timeout;
+ struct notifier_block reboot_nb;
struct notifier_block restart_nb;
void *driver_data;
struct mutex lock;
@@ -102,6 +104,7 @@
#define WDOG_ALLOW_RELEASE 2 /* Did we receive the magic char ? */
#define WDOG_NO_WAY_OUT 3 /* Is 'nowayout' feature set ? */
#define WDOG_UNREGISTERED 4 /* Has the device been unregistered */
+#define WDOG_STOP_ON_REBOOT 5 /* Should be stopped on reboot */
struct list_head deferred;
};
@@ -121,6 +124,12 @@
set_bit(WDOG_NO_WAY_OUT, &wdd->status);
}
+/* Use the following function to stop the watchdog on reboot */
+static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd)
+{
+ set_bit(WDOG_STOP_ON_REBOOT, &wdd->status);
+}
+
/* Use the following function to check if a timeout value is invalid */
static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t)
{
