On Thu, 2017-03-30 at 10:46 -0400, Sylvain Lemieux wrote: > Hi, > > On Thu, 2017-03-30 at 06:11 -0700, Guenter Roeck wrote: > > On 03/14/2017 07:11 AM, 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. > > > > > > > The description doesn't match what the code actually does, at least from > > an infrastructure perspective. The infrastructure would just keep it running. > > > I will need to send a new version with an updated description; > I will submit v3 later today or tomorrow. > I did not update the description after this patch was rebased on-top > of the "watchdog: gpio: keepalives" patch. > > > What you are really asking for is something the infrastructure should possibly > > do by itself automatically: To keep pinging a HW watchdog after close until > > the configured (software) timeout period expires. This would be in line with > > expectations. > > Do you want me to work on a generic version for this option? Sylvain > > Also, I seem to recall that the gpio_wdt patch this relies on has a problem > > if the watchdog is opened and closed repeatedly. It is still on my task list > > to track this down. > [...] > > Sylvain > > > > Guenter > > > > > 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
