MLK-25482: watchdog: imx2_wdt: clear WDOG_HW_RUNNING before suspend

For watchdog_ping_work is not freezable so that it maybe scheduled before
imx2_wdt_resume where watchdog clock is on, hence, kernel will hang in
imx2_wdt_ping with clock disabled, and then watchdog reset happen.
Prevent the above case by clearing WDOG_HW_RUNNING before suspend, and
restore it with ping in imx2_wdt_resume.

Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Reviewed-by: Jacky Bai <ping.bai@nxp.com>

diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
index b84f80f..d3751e9 100644 (file)
--- a/drivers/watchdog/imx2_wdt.c
+++ b/drivers/watchdog/imx2_wdt.c
@@ -357,6 +357,13 @@ static int __maybe_unused imx2_wdt_suspend(struct device *dev)
                 */
                __imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME);
                imx2_wdt_ping(wdog);
+
+               /*
+                * clear WDOG_HW_RUNNING to prevent watchdog_ping_work running
+                * before imx2_wdt_resume where clock enabled, otherwise kernel
+                * will hang and watchdog reset happen then.
+                */
+               clear_bit(WDOG_HW_RUNNING, &wdog->status);
        }
 
        clk_disable_unprepare(wdev->clk);
@@ -386,6 +393,7 @@ static int __maybe_unused imx2_wdt_resume(struct device *dev)
        if (imx2_wdt_is_running(wdev)) {
                imx2_wdt_set_timeout(wdog, wdog->timeout);
                imx2_wdt_ping(wdog);
+               set_bit(WDOG_HW_RUNNING, &wdog->status);
        }
 
        return 0;