ping On Tue, 2017-03-14 at 10:11 -0400, Sylvain Lemieux wrote: > From: Sylvain Lemieux <slemieux@xxxxxxxxxxx> > > There is a need to allow a grace period after the watchdog software > client has closed. It could be used for syncing the filesystem or > allow graceful termination while still providing a hardware reset > in case the system has hung. > > The "always-running" configuration from device-tree does not provide > this since it will automatically keep the hardware watchdog alive as > soon as the software client closes (i.e. keep toggling the GPIO line > regardless of the state of the soft part of the watchdog). > > The "keep-armed-on-close" member in the GPIO watchdog implementation > indicates if an expired timeout should cause a reset. > > This patch add a new "keep-armed-on-close" device-tree configuration > that will keep the watchdog "armed" until the next timeout period after > a close. During this period, the hardware watchdog is kept alive. > A software watchdog client that wants to provide a grace period before > a hard reset can set the timeout before properly closing. > > Signed-off-by: Sylvain Lemieux <slemieux@xxxxxxxxxxx> > --- > * This patch depend on the: > "watchdog: gpio: Convert to use infrastructure triggered keepalives"; > ref. https://lkml.org/lkml/2016/2/28/239 (version 8) > > Changes from v1 to v2: > * Rebased on-top of the "watchdog: gpio: keepalives" patch. > - Updated the management of the "WDOG_HW_RUNNING" flag. > * Tested with v4.11-rc1. > > Documentation/devicetree/bindings/watchdog/gpio-wdt.txt | 3 +++ > drivers/watchdog/gpio_wdt.c | 10 ++++++++++ > 2 files changed, 13 insertions(+) > > diff --git a/Documentation/devicetree/bindings/watchdog/gpio-wdt.txt b/Documentation/devicetree/bindings/watchdog/gpio-wdt.txt > index 83d28146e39b..48db076771b2 100644 > --- a/Documentation/devicetree/bindings/watchdog/gpio-wdt.txt > +++ b/Documentation/devicetree/bindings/watchdog/gpio-wdt.txt > @@ -17,6 +17,9 @@ Optional Properties: > - always-running: If the watchdog timer cannot be disabled, add this flag to > have the driver keep toggling the signal without a client. It will only cease > to toggle the signal when the device is open and the timeout elapsed. > +- keep-armed-on-close: if the watchdog timer need to keep toggling the signal > + when close, until the timeout elapsed, add this flag to have the driver > + keep toggling the signal, until the timeout elapsed. > - timeout-sec: Contains the watchdog timeout in seconds. > - start-at-init: Start kicking watchdog as soon as driver is loaded. > > diff --git a/drivers/watchdog/gpio_wdt.c b/drivers/watchdog/gpio_wdt.c > index 7b46d224cb56..2f4799bee9bd 100644 > --- a/drivers/watchdog/gpio_wdt.c > +++ b/drivers/watchdog/gpio_wdt.c > @@ -29,6 +29,7 @@ struct gpio_wdt_priv { > bool active_low; > bool state; > bool always_running; > + bool keep_armed_on_close; > unsigned int hw_algo; > struct watchdog_device wdd; > }; > @@ -78,6 +79,13 @@ static int gpio_wdt_stop(struct watchdog_device *wdd) > { > struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd); > > + if(priv->keep_armed_on_close) { > + /* Keep the driver running on close. */ > + set_bit(WDOG_HW_RUNNING, &wdd->status); > + > + return 0; > + } > + > if (!priv->always_running) { > gpio_wdt_disable(priv); > clear_bit(WDOG_HW_RUNNING, &wdd->status); > @@ -148,6 +156,8 @@ static int gpio_wdt_probe(struct platform_device *pdev) > > priv->always_running = of_property_read_bool(pdev->dev.of_node, > "always-running"); > + priv->keep_armed_on_close = of_property_read_bool(pdev->dev.of_node, > + "keep-armed-on-close"); > > watchdog_set_drvdata(&priv->wdd, priv); > -- To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
