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 <s.hauer@pengutronix.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20240703111603.1096424-1-s.hauer@pengutronix.deSigned-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

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);