On Wed, Dec 07, 2016 at 02:46:20PM -0500, 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> Rather than changing the current gpio watchdog code, I would prefer to start with https://lkml.org/lkml/2016/1/26/517, which moves part of its code into the watchdog core - even more so here since I suspect that the suggested changes won't work anymore after the above patch is applied. Also, isn't this quite identical to nowayout ? Thanks, Guenter > --- > Documentation/devicetree/bindings/watchdog/gpio-wdt.txt | 3 +++ > drivers/watchdog/gpio_wdt.c | 6 ++++++ > 2 files changed, 9 insertions(+) > > diff --git a/Documentation/devicetree/bindings/watchdog/gpio-wdt.txt b/Documentation/devicetree/bindings/watchdog/gpio-wdt.txt > index 83d2814..2669735 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 ef9ab91..ba9091a 100644 > --- a/drivers/watchdog/gpio_wdt.c > +++ b/drivers/watchdog/gpio_wdt.c > @@ -32,6 +32,7 @@ struct gpio_wdt_priv { > bool active_low; > bool state; > bool always_running; > + bool keep_armed_on_close; > bool armed; > unsigned int hw_algo; > unsigned int hw_margin; > @@ -72,6 +73,9 @@ static int gpio_wdt_stop(struct watchdog_device *wdd) > { > struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd); > > + if(priv->keep_armed_on_close) > + return 0; > + > priv->armed = false; > if (!priv->always_running) { > mod_timer(&priv->timer, 0); > @@ -210,6 +214,8 @@ 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); > > -- > 1.8.3.1 > -- 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
