From: Michael Walle <michael@walle.cc> commit ea104a9e4d3e9ebc26fb78dac35585b142ee288b upstream. The restart handler is missing two things, first, the registers has to be unlocked and second there is no synchronization for the write_relaxed() calls. This was tested on a custom board with the NXP LS1028A SoC. Fixes: 6c5c0d48b686c ("watchdog: sp805: add restart handler") Signed-off-by: Michael Walle <michael@walle.cc> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20200327162450.28506-1-michael@walle.cc Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/watchdog/sp805_wdt.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/watchdog/sp805_wdt.c b/drivers/watchdog/sp805_wdt.c index 072986d..d8876fb 100644 --- a/drivers/watchdog/sp805_wdt.c +++ b/drivers/watchdog/sp805_wdt.c @@ -137,10 +137,14 @@ static unsigned int wdt_timeleft(struct watchdog_device *wdd) { struct sp805_wdt *wdt = watchdog_get_drvdata(wdd); + writel_relaxed(UNLOCK, wdt->base + WDTLOCK); writel_relaxed(0, wdt->base + WDTCONTROL); writel_relaxed(0, wdt->base + WDTLOAD); writel_relaxed(INT_ENABLE | RESET_ENABLE, wdt->base + WDTCONTROL); + /* Flush posted writes. */ + readl_relaxed(wdt->base + WDTLOCK); + return 0; } -- 1.8.3