watchdog: Make stop function optional
Not all hardware watchdogs can be stopped. The driver for such watchdogs would typically only set the WATCHDOG_HW_RUNNING flag in its stop function. Make the stop function optional and set WATCHDOG_HW_RUNNING in the watchdog core if it is not provided. Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This commit is contained in:
parent
ee142889e3
commit
d0684c8a93
|
@ -85,7 +85,8 @@ It contains following fields:
|
|||
If set, the infrastructure will send heartbeats to the watchdog driver
|
||||
if 'timeout' is larger than max_hw_heartbeat_ms, unless WDOG_ACTIVE
|
||||
is set and userspace failed to send a heartbeat for at least 'timeout'
|
||||
seconds.
|
||||
seconds. max_hw_heartbeat_ms must be set if a driver does not implement
|
||||
the stop function.
|
||||
* reboot_nb: notifier block that is registered for reboot notifications, for
|
||||
internal use only. If the driver calls watchdog_stop_on_reboot, watchdog core
|
||||
will stop the watchdog on such notifications.
|
||||
|
@ -134,17 +135,20 @@ are:
|
|||
device.
|
||||
The routine needs a pointer to the watchdog timer device structure as a
|
||||
parameter. It returns zero on success or a negative errno code for failure.
|
||||
* stop: with this routine the watchdog timer device is being stopped.
|
||||
The routine needs a pointer to the watchdog timer device structure as a
|
||||
parameter. It returns zero on success or a negative errno code for failure.
|
||||
Some watchdog timer hardware can only be started and not be stopped.
|
||||
If a watchdog can not be stopped, the watchdog driver must set the
|
||||
WDOG_HW_RUNNING flag in its stop function to inform the watchdog core that
|
||||
the watchdog is still running.
|
||||
|
||||
Not all watchdog timer hardware supports the same functionality. That's why
|
||||
all other routines/operations are optional. They only need to be provided if
|
||||
they are supported. These optional routines/operations are:
|
||||
* stop: with this routine the watchdog timer device is being stopped.
|
||||
The routine needs a pointer to the watchdog timer device structure as a
|
||||
parameter. It returns zero on success or a negative errno code for failure.
|
||||
Some watchdog timer hardware can only be started and not be stopped. A
|
||||
driver supporting such hardware does not have to implement the stop routine.
|
||||
If a driver has no stop function, the watchdog core will set WDOG_HW_RUNNING
|
||||
and start calling the driver's keepalive pings function after the watchdog
|
||||
device is closed.
|
||||
If a watchdog driver does not implement the stop function, it must set
|
||||
max_hw_heartbeat_ms.
|
||||
* ping: this is the routine that sends a keepalive ping to the watchdog timer
|
||||
hardware.
|
||||
The routine needs a pointer to the watchdog timer device structure as a
|
||||
|
|
|
@ -199,7 +199,7 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
|
|||
return -EINVAL;
|
||||
|
||||
/* Mandatory operations need to be supported */
|
||||
if (wdd->ops->start == NULL || wdd->ops->stop == NULL)
|
||||
if (!wdd->ops->start || (!wdd->ops->stop && !wdd->max_hw_heartbeat_ms))
|
||||
return -EINVAL;
|
||||
|
||||
watchdog_check_min_max_timeout(wdd);
|
||||
|
|
|
@ -246,7 +246,11 @@ static int watchdog_stop(struct watchdog_device *wdd)
|
|||
return -EBUSY;
|
||||
}
|
||||
|
||||
if (wdd->ops->stop)
|
||||
err = wdd->ops->stop(wdd);
|
||||
else
|
||||
set_bit(WDOG_HW_RUNNING, &wdd->status);
|
||||
|
||||
if (err == 0) {
|
||||
clear_bit(WDOG_ACTIVE, &wdd->status);
|
||||
watchdog_update_worker(wdd);
|
||||
|
|
Loading…
Reference in New Issue