diff options
| -rw-r--r-- | Documentation/watchdog/watchdog-kernel-api.rst | 12 | ||||
| -rw-r--r-- | drivers/watchdog/watchdog_dev.c | 30 | ||||
| -rw-r--r-- | include/linux/watchdog.h | 2 |
3 files changed, 44 insertions, 0 deletions
diff --git a/Documentation/watchdog/watchdog-kernel-api.rst b/Documentation/watchdog/watchdog-kernel-api.rst index 068a55ee0d4a..baf44e986b07 100644 --- a/Documentation/watchdog/watchdog-kernel-api.rst +++ b/Documentation/watchdog/watchdog-kernel-api.rst @@ -336,3 +336,15 @@ an action is taken by a preconfigured pretimeout governor preassigned to the watchdog device. If watchdog pretimeout governor framework is not enabled, watchdog_notify_pretimeout() prints a notification message to the kernel log buffer. + +To set the last known HW keepalive time for a watchdog, the following function +should be used:: + + int watchdog_set_last_hw_keepalive(struct watchdog_device *wdd, + unsigned int last_ping_ms) + +This function must be called immediately after watchdog registration. It +sets the last known hardware heartbeat to have happened last_ping_ms before +current time. Calling this is only needed if the watchdog is already running +when probe is called, and the watchdog can only be pinged after the +min_hw_heartbeat_ms time has passed from the last ping. diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index 0ad1c393c00e..531e74994b61 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -1139,6 +1139,36 @@ void watchdog_dev_unregister(struct watchdog_device *wdd) } /* + * watchdog_set_last_hw_keepalive: set last HW keepalive time for watchdog + * @wdd: watchdog device + * @last_ping_ms: time since last HW heartbeat + * + * Adjusts the last known HW keepalive time for a watchdog timer. + * This is needed if the watchdog is already running when the probe + * function is called, and it can't be pinged immediately. This + * function must be called immediately after watchdog registration, + * and min_hw_heartbeat_ms must be set for this to be useful. + */ +int watchdog_set_last_hw_keepalive(struct watchdog_device *wdd, + unsigned int last_ping_ms) +{ + struct watchdog_core_data *wd_data; + ktime_t now; + + if (!wdd) + return -EINVAL; + + wd_data = wdd->wd_data; + + now = ktime_get(); + + wd_data->last_hw_keepalive = ktime_sub(now, ms_to_ktime(last_ping_ms)); + + return __watchdog_ping(wdd); +} +EXPORT_SYMBOL_GPL(watchdog_set_last_hw_keepalive); + +/* * watchdog_dev_init: init dev part of watchdog core * * Allocate a range of chardev nodes to use for watchdog devices diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h index 1464ce6ffa31..9b19e6bb68b5 100644 --- a/include/linux/watchdog.h +++ b/include/linux/watchdog.h @@ -210,6 +210,8 @@ extern int watchdog_init_timeout(struct watchdog_device *wdd, extern int watchdog_register_device(struct watchdog_device *); extern void watchdog_unregister_device(struct watchdog_device *); +int watchdog_set_last_hw_keepalive(struct watchdog_device *, unsigned int); + /* devres register variant */ int devm_watchdog_register_device(struct device *dev, struct watchdog_device *); |