diff options
| -rw-r--r-- | Documentation/watchdog/watchdog-kernel-api.txt | 3 | ||||
| -rw-r--r-- | drivers/watchdog/watchdog_dev.c | 15 | ||||
| -rw-r--r-- | include/linux/watchdog.h | 3 |
3 files changed, 21 insertions, 0 deletions
diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt index 9eabca1d9355..917eeeabfa5e 100644 --- a/Documentation/watchdog/watchdog-kernel-api.txt +++ b/Documentation/watchdog/watchdog-kernel-api.txt @@ -52,6 +52,7 @@ struct watchdog_device { unsigned int timeout; unsigned int min_timeout; unsigned int max_timeout; + unsigned int min_hw_heartbeat_ms; unsigned int max_hw_heartbeat_ms; struct notifier_block reboot_nb; struct notifier_block restart_nb; @@ -81,6 +82,8 @@ It contains following fields: * max_timeout: the watchdog timer's maximum timeout value (in seconds), as seen from userspace. If set, the maximum configurable value for 'timeout'. Not used if max_hw_heartbeat_ms is non-zero. +* min_hw_heartbeat_ms: Minimum time between heartbeats sent to the chip, + in milli-seconds. * max_hw_heartbeat_ms: Maximum hardware heartbeat, in milli-seconds. If set, the infrastructure will send heartbeats to the watchdog driver if 'timeout' is larger than max_hw_heartbeat_ms, unless WDOG_ACTIVE diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index 5163c3eb3428..2d6110278eac 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -64,6 +64,7 @@ struct watchdog_core_data { struct watchdog_device *wdd; struct mutex lock; unsigned long last_keepalive; + unsigned long last_hw_keepalive; struct delayed_work work; unsigned long status; /* Internal status bits */ #define _WDOG_DEV_OPEN 0 /* Opened ? */ @@ -137,8 +138,19 @@ static inline void watchdog_update_worker(struct watchdog_device *wdd) static int __watchdog_ping(struct watchdog_device *wdd) { + struct watchdog_core_data *wd_data = wdd->wd_data; + unsigned long earliest_keepalive = wd_data->last_hw_keepalive + + msecs_to_jiffies(wdd->min_hw_heartbeat_ms); int err; + if (time_is_after_jiffies(earliest_keepalive)) { + mod_delayed_work(watchdog_wq, &wd_data->work, + earliest_keepalive - jiffies); + return 0; + } + + wd_data->last_hw_keepalive = jiffies; + if (wdd->ops->ping) err = wdd->ops->ping(wdd); /* ping the watchdog */ else @@ -819,6 +831,9 @@ static int watchdog_cdev_register(struct watchdog_device *wdd, dev_t devno) return err; } + /* Record time of most recent heartbeat as 'just before now'. */ + wd_data->last_hw_keepalive = jiffies - 1; + /* * If the watchdog is running, prevent its driver from being unloaded, * and schedule an immediate ping. diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h index e2f45549b243..51732d6c9555 100644 --- a/include/linux/watchdog.h +++ b/include/linux/watchdog.h @@ -65,6 +65,8 @@ struct watchdog_ops { * @max_timeout:The watchdog devices maximum timeout value (in seconds) * as configurable from user space. Only relevant if * max_hw_heartbeat_ms is not provided. + * @min_hw_heartbeat_ms: + * Minimum time between heartbeats, in milli-seconds. * @max_hw_heartbeat_ms: * Hardware limit for maximum timeout, in milli-seconds. * Replaces max_timeout if specified. @@ -95,6 +97,7 @@ struct watchdog_device { unsigned int timeout; unsigned int min_timeout; unsigned int max_timeout; + unsigned int min_hw_heartbeat_ms; unsigned int max_hw_heartbeat_ms; struct notifier_block reboot_nb; struct notifier_block restart_nb; |