watchdog: sp805: add restart handler

Add restart handler for SP805 watchdog so that the driver can be
used to reboot the system.
Signed-off-by: Jongsung Kim <neidhard.kim@lge.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/sp805_wdt.c

@@ -121,6 +121,18 @@ static unsigned int wdt_timeleft(struct watchdog_device *wdd)
 	return div_u64(load, rate);
 }
 
+static int
+wdt_restart(struct watchdog_device *wdd, unsigned long mode, void *cmd)
+{
+	struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
+
+	writel_relaxed(0, wdt->base + WDTCONTROL);
+	writel_relaxed(0, wdt->base + WDTLOAD);
+	writel_relaxed(INT_ENABLE | RESET_ENABLE, wdt->base + WDTCONTROL);
+
+	return 0;
+}
+
 static int wdt_config(struct watchdog_device *wdd, bool ping)
 {
 	struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
@@ -197,6 +209,7 @@ static const struct watchdog_ops wdt_ops = {
 	.ping		= wdt_ping,
 	.set_timeout	= wdt_setload,
 	.get_timeleft	= wdt_timeleft,
+	.restart	= wdt_restart,
 };
 
 static int
@@ -230,6 +243,7 @@ sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
 	spin_lock_init(&wdt->lock);
 	watchdog_set_nowayout(&wdt->wdd, nowayout);
 	watchdog_set_drvdata(&wdt->wdd, wdt);
+	watchdog_set_restart_priority(&wdt->wdd, 128);
 	wdt_setload(&wdt->wdd, DEFAULT_TIMEOUT);
 
 	ret = watchdog_register_device(&wdt->wdd);