watchdog: msc313e: Check if the WDT was running at boot

Check if the WDT was running at boot and set the running
flag if it was. This prevents the system from getting
rebooted if the userland daemon doesn't take over soon enough
or there isn't a userland daemon at all.
Signed-off-by: Daniel Palmer <daniel@0x0f.com>
Reviewed-by: Romain Perier <romain.perier@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20211228073427.2443174-1-daniel@0x0f.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

drivers/watchdog/msc313e_wdt.c

@@ -120,6 +120,10 @@ static int msc313e_wdt_probe(struct platform_device *pdev)
 	priv->wdev.max_timeout = U32_MAX / clk_get_rate(priv->clk);
 	priv->wdev.timeout = MSC313E_WDT_DEFAULT_TIMEOUT;
 
+	/* If the period is non-zero the WDT is running */
+	if (readw(priv->base + REG_WDT_MAX_PRD_L) | (readw(priv->base + REG_WDT_MAX_PRD_H) << 16))
+		set_bit(WDOG_HW_RUNNING, &priv->wdev.status);
+
 	watchdog_set_drvdata(&priv->wdev, priv);
 
 	watchdog_init_timeout(&priv->wdev, timeout, dev);