Hello Guenter, On Mon, Jan 25, 2016 at 06:53:11PM -0800, Guenter Roeck wrote: > From: Guenter Roeck <[email protected]> > > Some watchdogs require a minimum time between heartbeats. > Examples are the watchdogs in DA9062 and AT91SAM9x. > > Signed-off-by: Guenter Roeck <[email protected]> > --- > v7: Rebased to v4.5-rc1 > v6: Rebased to v4.4-rc2 > v5: Rebased to v4.4-rc1 > Fixed typo in documentation. > v4: Added patch > --- > Documentation/watchdog/watchdog-kernel-api.txt | 3 +++ > drivers/watchdog/watchdog_dev.c | 15 +++++++++++++++ > include/linux/watchdog.h | 3 +++ > 3 files changed, 21 insertions(+) > > diff --git a/Documentation/watchdog/watchdog-kernel-api.txt > b/Documentation/watchdog/watchdog-kernel-api.txt > index 62d49d6a7ff5..2221fb4f2739 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_timeout_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_timeout_ms is non-zero. > +* min_hw_heartbeat_ms: Minimum time between heartbeats sent to the chip, > + in milli-seconds. > * max_hw_timeout_ms: Maximum hardware timeout, in milli-seconds. > If set, the infrastructure will send heartbeats to the watchdog driver > if 'timeout' is larger than max_hw_timeout_ms, unless WDOG_ACTIVE > diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c > index 1a8f3861fe92..ff03cbc8e081 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 ? */ > @@ -138,8 +139,19 @@ 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; > +
Do you need to undo this assignment when ping fails? > if (wdd->ops->ping) > err = wdd->ops->ping(wdd); /* ping the watchdog */ > else Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |
