1 files changed, 42 insertions, 18 deletions

diff --git a/drivers/watchdog/ixp4xx_wdt.c b/drivers/watchdog/ixp4xx_wdt.c
index 31b03fa71341..ec0c08652ec2 100644
--- a/drivers/watchdog/ixp4xx_wdt.c
+++ b/drivers/watchdog/ixp4xx_wdt.c
@@ -84,10 +84,43 @@ static int ixp4xx_wdt_set_timeout(struct watchdog_device *wdd,
 	return 0;
 }
 
+static int ixp4xx_wdt_restart(struct watchdog_device *wdd,
+                              unsigned long action, void *data)
+{
+	struct ixp4xx_wdt *iwdt = to_ixp4xx_wdt(wdd);
+
+	__raw_writel(IXP4XX_WDT_KEY, iwdt->base + IXP4XX_OSWK_OFFSET);
+	__raw_writel(0, iwdt->base + IXP4XX_OSWT_OFFSET);
+	__raw_writel(IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE,
+		     iwdt->base + IXP4XX_OSWE_OFFSET);
+
+	return 0;
+}
+
 static const struct watchdog_ops ixp4xx_wdt_ops = {
 	.start = ixp4xx_wdt_start,
 	.stop = ixp4xx_wdt_stop,
 	.set_timeout = ixp4xx_wdt_set_timeout,
+	.restart = ixp4xx_wdt_restart,
+	.owner = THIS_MODULE,
+};
+
+/*
+ * The A0 version of the IXP422 had a bug in the watchdog making
+ * is useless, but we still need to use it to restart the system
+ * as it is the only way, so in this special case we register a
+ * "dummy" watchdog that doesn't really work, but will support
+ * the restart operation.
+ */
+static int ixp4xx_wdt_dummy(struct watchdog_device *wdd)
+{
+	return 0;
+}
+
+static const struct watchdog_ops ixp4xx_wdt_restart_only_ops = {
+	.start = ixp4xx_wdt_dummy,
+	.stop = ixp4xx_wdt_dummy,
+	.restart = ixp4xx_wdt_restart,
 	.owner = THIS_MODULE,
 };
 
@@ -98,22 +131,19 @@ static const struct watchdog_info ixp4xx_wdt_info = {
 	.identity = KBUILD_MODNAME,
 };
 
-/* Devres-handled clock disablement */
-static void ixp4xx_clock_action(void *d)
-{
-	clk_disable_unprepare(d);
-}
-
 static int ixp4xx_wdt_probe(struct platform_device *pdev)
 {
+	static const struct watchdog_ops *iwdt_ops;
 	struct device *dev = &pdev->dev;
 	struct ixp4xx_wdt *iwdt;
 	struct clk *clk;
 	int ret;
 
 	if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
-		dev_err(dev, "Rev. A0 IXP42x CPU detected - watchdog disabled\n");
-		return -ENODEV;
+		dev_info(dev, "Rev. A0 IXP42x CPU detected - only restart supported\n");
+		iwdt_ops = &ixp4xx_wdt_restart_only_ops;
+	} else {
+		iwdt_ops = &ixp4xx_wdt_ops;
 	}
 
 	iwdt = devm_kzalloc(dev, sizeof(*iwdt), GFP_KERNEL);
@@ -125,21 +155,15 @@ static int ixp4xx_wdt_probe(struct platform_device *pdev)
 	 * Retrieve rate from a fixed clock from the device tree if
 	 * the parent has that, else use the default clock rate.
 	 */
-	clk = devm_clk_get(dev->parent, NULL);
-	if (!IS_ERR(clk)) {
-		ret = clk_prepare_enable(clk);
-		if (ret)
-			return ret;
-		ret = devm_add_action_or_reset(dev, ixp4xx_clock_action, clk);
-		if (ret)
-			return ret;
+	clk = devm_clk_get_enabled(dev->parent, NULL);
+	if (!IS_ERR(clk))
 		iwdt->rate = clk_get_rate(clk);
-	}
+
 	if (!iwdt->rate)
 		iwdt->rate = IXP4XX_TIMER_FREQ;
 
 	iwdt->wdd.info = &ixp4xx_wdt_info;
-	iwdt->wdd.ops = &ixp4xx_wdt_ops;
+	iwdt->wdd.ops = iwdt_ops;
 	iwdt->wdd.min_timeout = 1;
 	iwdt->wdd.max_timeout = U32_MAX / iwdt->rate;
 	iwdt->wdd.parent = dev;