From: Robin Gong Date: Fri, 14 May 2021 17:21:15 +0000 (+0800) Subject: watchdog: imx2_wdt: avoid to ping before resume back X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=e0b101ab01c719a5a81b21ff16bbd33a868f9189;p=linux.git watchdog: imx2_wdt: avoid to ping before resume back Since watchdog_ping_work is not freezable so that it maybe scheduled before imx2_wdt_resume where watchdog clock enabled, hence, kernel will hang in imx2_wdt_ping without clock, and then watchdog reset happen. Add clk_is_on to prevent the above case by ignoring ping until watchdog driver resume back indeed. Signed-off-by: Robin Gong Reviewed-by: Guenter Roeck Link: https://lore.kernel.org/r/1621012875-22667-1-git-send-email-yibin.gong@nxp.com Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck --- diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c index b84f80f7d3421..cc86018c5eb56 100644 --- a/drivers/watchdog/imx2_wdt.c +++ b/drivers/watchdog/imx2_wdt.c @@ -65,6 +65,7 @@ struct imx2_wdt_device { struct regmap *regmap; struct watchdog_device wdog; bool ext_reset; + bool clk_is_on; }; static bool nowayout = WATCHDOG_NOWAYOUT; @@ -160,6 +161,9 @@ static int imx2_wdt_ping(struct watchdog_device *wdog) { struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); + if (!wdev->clk_is_on) + return 0; + regmap_write(wdev->regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ1); regmap_write(wdev->regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ2); return 0; @@ -301,6 +305,8 @@ static int __init imx2_wdt_probe(struct platform_device *pdev) if (ret) return ret; + wdev->clk_is_on = true; + regmap_read(wdev->regmap, IMX2_WDT_WRSR, &val); wdog->bootstatus = val & IMX2_WDT_WRSR_TOUT ? WDIOF_CARDRESET : 0; @@ -361,6 +367,8 @@ static int __maybe_unused imx2_wdt_suspend(struct device *dev) clk_disable_unprepare(wdev->clk); + wdev->clk_is_on = false; + return 0; } @@ -375,6 +383,8 @@ static int __maybe_unused imx2_wdt_resume(struct device *dev) if (ret) return ret; + wdev->clk_is_on = true; + if (watchdog_active(wdog) && !imx2_wdt_is_running(wdev)) { /* * If the watchdog is still active and resumes