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 <vivien.didelot@savoirfairelinux.com>
Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
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>
diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
index 88a34ef..0bb32a4 100644
--- a/drivers/watchdog/watchdog_core.c
+++ b/drivers/watchdog/watchdog_core.c
@@ -138,6 +138,25 @@
}
EXPORT_SYMBOL_GPL(watchdog_init_timeout);
+static int watchdog_reboot_notifier(struct notifier_block *nb,
+ unsigned long code, void *data)
+{
+ struct watchdog_device *wdd = container_of(nb, struct watchdog_device,
+ reboot_nb);
+
+ if (code == SYS_DOWN || code == SYS_HALT) {
+ if (watchdog_active(wdd)) {
+ int ret;
+
+ ret = wdd->ops->stop(wdd);
+ if (ret)
+ return NOTIFY_BAD;
+ }
+ }
+
+ return NOTIFY_DONE;
+}
+
static int watchdog_restart_notifier(struct notifier_block *nb,
unsigned long action, void *data)
{
@@ -238,6 +257,21 @@
return ret;
}
+ if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status)) {
+ wdd->reboot_nb.notifier_call = watchdog_reboot_notifier;
+
+ ret = register_reboot_notifier(&wdd->reboot_nb);
+ if (ret) {
+ dev_err(wdd->dev, "Cannot register reboot notifier (%d)\n",
+ ret);
+ watchdog_dev_unregister(wdd);
+ device_destroy(watchdog_class, devno);
+ ida_simple_remove(&watchdog_ida, wdd->id);
+ wdd->dev = NULL;
+ return ret;
+ }
+ }
+
if (wdd->ops->restart) {
wdd->restart_nb.notifier_call = watchdog_restart_notifier;
@@ -286,6 +320,9 @@
if (wdd->ops->restart)
unregister_restart_handler(&wdd->restart_nb);
+ if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status))
+ unregister_reboot_notifier(&wdd->reboot_nb);
+
devno = wdd->cdev.dev;
ret = watchdog_dev_unregister(wdd);
if (ret)