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| author | Boris BREZILLON <b.brezillon@overkiz.com> | 2013-11-03 18:52:43 +0100 |
|---|---|---|
| committer | Wim Van Sebroeck <wim@iguana.be> | 2014-01-28 21:34:38 +0100 |
| commit | a04c3f01d33f4661424deeff67913699a0910c53 (patch) | |
| tree | 0632c5a099c300fe0414244cebe8dce8ce051334 /drivers/watchdog/at91sam9_wdt.c | |
| parent | 1444797fc178b58e91cf29a438efd05dd890d43a (diff) | |
| download | lwn-a04c3f01d33f4661424deeff67913699a0910c53.tar.gz lwn-a04c3f01d33f4661424deeff67913699a0910c53.zip | |
watchdog: at91sam9_wdt: avoid spurious watchdog reset during init
Use the min_heartbeat value instead of the calculated heartbeat value for
the first watchdog reset to avoid spurious watchdog reset.
Resetting the watchdog counter during init might lead to a watchdog fault
reset because the watchdog counter has to be running for at least
min_heartbeat.
Resetting the watchdog counter after heartbeat might lead to a watchdog
timeout reset because the watchdog counter is running for more than
max_heartbeat time.
Using min_heartbeat instead of heartbeat does not guarantee that the
watchdog won't trigger a reset, but at least it reduces the chances to be
in such a case.
Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Diffstat (limited to 'drivers/watchdog/at91sam9_wdt.c')
| -rw-r--r-- | drivers/watchdog/at91sam9_wdt.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/watchdog/at91sam9_wdt.c b/drivers/watchdog/at91sam9_wdt.c index 65f469145950..ab0c4e0165d1 100644 --- a/drivers/watchdog/at91sam9_wdt.c +++ b/drivers/watchdog/at91sam9_wdt.c @@ -213,7 +213,15 @@ static int at91_wdt_init(struct platform_device *pdev, struct at91wdt *wdt) tmp & wdt->mr_mask, wdt->mr & wdt->mr_mask); setup_timer(&wdt->timer, at91_ping, (unsigned long)wdt); - mod_timer(&wdt->timer, jiffies + wdt->heartbeat); + + /* + * Use min_heartbeat the first time to avoid spurious watchdog reset: + * we don't know for how long the watchdog counter is running, and + * - resetting it right now might trigger a watchdog fault reset + * - waiting for heartbeat time might lead to a watchdog timeout + * reset + */ + mod_timer(&wdt->timer, jiffies + min_heartbeat); /* Try to set timeout from device tree first */ if (watchdog_init_timeout(&wdt->wdd, 0, dev)) |