watchdog: imx7ulp_wdt: keep already running watchdog enabled

When the bootloader enabled the watchdog before Kernel started then
keep it enabled during initialization. Otherwise the time between
the watchdog probing and the userspace taking over the watchdog
won't be covered by the watchdog. When keeping the watchdog enabled
inform the Kernel about this by setting the WDOG_HW_RUNNING so that
the periodic watchdog feeder is started when desired.

Signed-off-by: Sascha Hauer <[email protected]>
Reviewed-by: Guenter Roeck <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Guenter Roeck <[email protected]>
Signed-off-by: Wim Van Sebroeck <[email protected]>

Author: saschahauer

drivers/watchdog/imx7ulp_wdt.c

@@ -290,6 +290,11 @@ static int imx7ulp_wdt_init(struct imx7ulp_wdt_device *wdt, unsigned int timeout
 	if (wdt->ext_reset)
 		val |= WDOG_CS_INT_EN;
 
+	if (readl(wdt->base + WDOG_CS) & WDOG_CS_EN) {
+		set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
+		val |= WDOG_CS_EN;
+	}
+
 	do {
 		ret = _imx7ulp_wdt_init(wdt, timeout, val);
 		toval = readl(wdt->base + WDOG_TOVAL);