[v2] watchdog: softdog: implement pretimeout support

Commit Message

Wolfram Sang Aug. 30, 2016, 3:03 p.m. UTC

From: Wolfram Sang <[e-mail]>

Give devices which do not have hardware support for pretimeout at least a
software version of it.

Signed-off-by: Wolfram Sang <[e-mail]>
---

Change since v1: added 'else' block in softdog_ping(), to actually
disable the timer when pretimeout value got cleared.

Depends on the V4 pretimeout series from Vladimir.

Vladimir: Maybe you could add this patch to the next revision of your
pretimeout series? Then people have something to play around with
right away.

 drivers/watchdog/softdog.c | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

Comments

Vladimir Zapolskiy Aug. 30, 2016, 4:11 p.m. UTC | #1

Hi Wolfram,

On 08/30/2016 06:03 PM, Wolfram Sang wrote:
> From: Wolfram Sang <[e-mail]>
>
> Give devices which do not have hardware support for pretimeout at least a
> software version of it.
>
> Signed-off-by: Wolfram Sang <[e-mail]>
> ---
>
> Change since v1: added 'else' block in softdog_ping(), to actually
> disable the timer when pretimeout value got cleared.
>
> Depends on the V4 pretimeout series from Vladimir.
>
> Vladimir: Maybe you could add this patch to the next revision of your
> pretimeout series? Then people have something to play around with
> right away.

I'll add it to the series, and most probably I'll add a pretimeout
support to the iMX watchdog driver.

The v5 series will be published today tonight or tomorrow.

--
Best wishes,
Vladimir

Patch

diff --git a/drivers/watchdog/softdog.c b/drivers/watchdog/softdog.c
index b067edf246dff2..bab31b8df847a5 100644
--- a/drivers/watchdog/softdog.c
+++ b/drivers/watchdog/softdog.c
@@ -72,10 +72,27 @@  static void softdog_fire(unsigned long data)
 static struct timer_list softdog_ticktock =
 		TIMER_INITIALIZER(softdog_fire, 0, 0);
 
+static struct watchdog_device softdog_dev;
+
+static void softdog_pretimeout(unsigned long data)
+{
+	watchdog_notify_pretimeout(&softdog_dev);
+}
+
+static struct timer_list softdog_preticktock =
+		TIMER_INITIALIZER(softdog_pretimeout, 0, 0);
+
 static int softdog_ping(struct watchdog_device *w)
 {
 	if (!mod_timer(&softdog_ticktock, jiffies + (w->timeout * HZ)))
 		__module_get(THIS_MODULE);
+
+	if (w->pretimeout)
+		mod_timer(&softdog_preticktock, jiffies +
+		          (w->timeout - w->pretimeout) * HZ);
+	else
+		del_timer(&softdog_preticktock);
+
 	return 0;
 }
 
@@ -84,12 +101,15 @@  static int softdog_stop(struct watchdog_device *w)
 	if (del_timer(&softdog_ticktock))
 		module_put(THIS_MODULE);
 
+	del_timer(&softdog_preticktock);
+
 	return 0;
 }
 
 static struct watchdog_info softdog_info = {
 	.identity = "Software Watchdog",
-	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE |
+		   WDIOF_PRETIMEOUT,
 };
 
 static struct watchdog_ops softdog_ops = {