@@ -14,6 +14,7 @@
  */
 
 #include <linux/clk.h>
+#include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/io.h>

@@ -22,9 +23,12 @@
 #include <linux/moduleparam.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
+#include <linux/reboot.h>
 #include <linux/types.h>
 #include <linux/watchdog.h>
 
+#include <asm/system_misc.h>
+
 #define WDT_MAX_TIMEOUT         16
 #define WDT_MIN_TIMEOUT         1
 #define WDT_MODE_TIMEOUT(n)     ((n) << 3)

@@ -70,6 +74,26 @@ static const int wdt_timeout_map[] = {
 	[16] = 0b1011, /* 16s */
 };
 
+static void __iomem *reboot_wdt_base;
+
+static void sun4i_wdt_restart(enum reboot_mode mode, const char *cmd)
+{
+	/* Enable timer and set reset bit in the watchdog */
+	writel(WDT_MODE_EN | WDT_MODE_RST_EN, reboot_wdt_base + WDT_MODE);
+
+	/*
+	 * Restart the watchdog. The default (and lowest) interval
+	 * value for the watchdog is 0.5s.
+	 */
+	writel(WDT_CTRL_RELOAD, reboot_wdt_base + WDT_CTRL);
+
+	while (1) {
+		mdelay(5);
+		writel(WDT_MODE_EN | WDT_MODE_RST_EN,
+		       reboot_wdt_base + WDT_MODE);
+	}
+}
+
 static int sunxi_wdt_ping(struct watchdog_device *wdt_dev)
 {
 	struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);

@@ -181,6 +205,9 @@ static int sunxi_wdt_probe(struct platform_device *pdev)
 	if (unlikely(err))
 		return err;
 
+	reboot_wdt_base = sunxi_wdt->wdt_base;
+	arm_pm_restart = sun4i_wdt_restart;
+
 	dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
 			sunxi_wdt->wdt_dev.timeout, nowayout);
 

@@ -191,6 +218,8 @@ static int sunxi_wdt_remove(struct platform_device *pdev)
 {
 	struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
 
+	arm_pm_restart = NULL;
+
 	watchdog_unregister_device(&sunxi_wdt->wdt_dev);
 	watchdog_set_drvdata(&sunxi_wdt->wdt_dev, NULL);