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authorGuenter Roeck <linux@roeck-us.net>2016-02-28 13:12:18 -0800
committerWim Van Sebroeck <wim@iguana.be>2016-03-16 21:11:19 +0100
commit15013ad813f6544be8e79afc23672745950d59bc (patch)
tree8cb6da1a21407a0a30d8430fb10a6993863c371b /drivers/watchdog/watchdog_dev.c
parentd0684c8a9354953efdea214b437445c00743cf49 (diff)
watchdog: Add support for minimum time between heartbeats
Some watchdogs require a minimum time between heartbeats. Examples are the watchdogs in DA9062 and AT91SAM9x. Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Diffstat (limited to 'drivers/watchdog/watchdog_dev.c')
-rw-r--r--drivers/watchdog/watchdog_dev.c15
1 files changed, 15 insertions, 0 deletions
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.