On Wed, Jun 05, 2019 at 02:06:44PM +0000, Rasmus Villemoes wrote: > When the watchdog device is not open by userspace, the kernel takes > care of pinging it. When the open_timeout feature is in use, we should > ensure that the hardware fires close to open_timeout seconds after the > kernel has assumed responsibility for the device. > > To do this, simply reuse the logic that is already in place for > ensuring the same thing when userspace is responsible for regularly > pinging the device: > > - When watchdog_active(wdd), this patch doesn't change anything. > > - When !watchdoc_active(wdd), the "virtual timeout" should be taken to s/watchdoc_active/watchdog_active/ otherwise Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx> > be ->open_deadline". When the open_timeout feature is not used or the > device has been opened at least once, ->open_deadline is KTIME_MAX, > and the arithmetic ends up returning keepalive_interval as we used to. > > This has been tested on a Wandboard with various combinations of > open_timeout and timeout-sec properties for the on-board watchdog by > booting with 'init=/bin/sh', timestamping the lines on the serial > console, and comparing the timestamp of the 'imx2-wdt 20bc000.wdog: > timeout nnn sec' line with the timestamp of the 'U-Boot SPL ...' > line (which appears just after reset). > > Suggested-by: Guenter Roeck <linux@xxxxxxxxxxxx> > Signed-off-by: Rasmus Villemoes <rasmus.villemoes@xxxxxxxxx> > --- > drivers/watchdog/watchdog_dev.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c > index 334b810db2cf..edfb884044e0 100644 > --- a/drivers/watchdog/watchdog_dev.c > +++ b/drivers/watchdog/watchdog_dev.c > @@ -133,14 +133,15 @@ static ktime_t watchdog_next_keepalive(struct watchdog_device *wdd) > ktime_t virt_timeout; > unsigned int hw_heartbeat_ms; > > - virt_timeout = ktime_add(wd_data->last_keepalive, > - ms_to_ktime(timeout_ms)); > + if (watchdog_active(wdd)) > + virt_timeout = ktime_add(wd_data->last_keepalive, > + ms_to_ktime(timeout_ms)); > + else > + virt_timeout = wd_data->open_deadline; > + > hw_heartbeat_ms = min_not_zero(timeout_ms, wdd->max_hw_heartbeat_ms); > keepalive_interval = ms_to_ktime(hw_heartbeat_ms / 2); > > - if (!watchdog_active(wdd)) > - return keepalive_interval; > - > /* > * To ensure that the watchdog times out wdd->timeout seconds > * after the most recent ping from userspace, the last
