linux-kernel - [PATCH v2 2/2] watchdog: imx2_wdg: notify wdog core to stop ping worker on suspend

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Date:   Fri, 18 Jun 2021 21:50:33 +0200
From:   Grzegorz Jaszczyk <grzegorz.jaszczyk@...aro.org>
To:     wim@...ux-watchdog.org, linux@...ck-us.net, shawnguo@...nel.org
Cc:     linux-watchdog@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        grzegorz.jaszczyk@...aro.org,
        Michal Koziel <michal.koziel@...ogic.no>
Subject: [PATCH v2 2/2] watchdog: imx2_wdg: notify wdog core to stop ping worker on suspend

Suspend routine disables wdog clk. Nevertheless, the watchdog subsystem
is not aware of that and can still try to ping wdog through
watchdog_ping_work. In order to prevent such condition and therefore
prevent from system hang (caused by the wdog register access issued
while the wdog clock is disabled) notify watchdog core that the ping
worker should be canceled during watchdog core suspend and restored
during resume.

Signed-off-by: Michal Koziel <michal.koziel@...ogic.no>
Signed-off-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@...aro.org>
---
v1->v2:
- Do not use watchdog_dev_suspend/resume directly, instead notify the
watchdog core that the ping worker should be canceled during watchdog
core suspend and restored during resume.
- Commit log was updated accordingly.
---
 drivers/watchdog/imx2_wdt.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
index b84f80f7d342..3e8d9c3b6386 100644
--- a/drivers/watchdog/imx2_wdt.c
+++ b/drivers/watchdog/imx2_wdt.c
@@ -311,6 +311,7 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
 	watchdog_set_nowayout(wdog, nowayout);
 	watchdog_set_restart_priority(wdog, 128);
 	watchdog_init_timeout(wdog, timeout, dev);
+	watchdog_stop_ping_on_suspend(wdog);
 
 	if (imx2_wdt_is_running(wdev)) {
 		imx2_wdt_set_timeout(wdog, wdog->timeout);
-- 
2.29.0