watchdog: Integrate watchdog triggering into the cyclic framework

This patch integrates the watchdog triggering into the recently added
cyclic infrastructure. Each watchdog device that shall be triggered
registers it's own cyclic function. This way, multiple watchdog devices
are still supported, each via a cyclic function with separate trigger
intervals.

Signed-off-by: Stefan Roese <sr@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Tom Rini <trini@konsulko.com> [am335x_evm, mx6cuboxi, rpi_3,dra7xx_evm, pine64_plus, am65x_evm, j721e_evm]

drivers/watchdog/Kconfig

@@ -3,6 +3,7 @@ menu "Watchdog Timer Support"
 config WATCHDOG
 	bool "Enable U-Boot watchdog reset"
 	depends on !HW_WATCHDOG
+	select CYCLIC
 	help
 	  This option enables U-Boot watchdog support where U-Boot is using
 	  watchdog_reset function to service watchdog device in U-Boot. Enable
@@ -74,6 +75,7 @@ config WDT
 	bool "Enable driver model for watchdog timer drivers"
 	depends on DM
 	imply WATCHDOG
+	select CYCLIC
 	help
 	  Enable driver model for watchdog timer. At the moment the API
 	  is very simple and only supports four operations:

drivers/watchdog/wdt-uclass.c

@@ -6,6 +6,7 @@
 #define LOG_CATEGORY UCLASS_WDT
 
 #include <common.h>
+#include <cyclic.h>
 #include <dm.h>
 #include <errno.h>
 #include <hang.h>
@@ -38,8 +39,25 @@ struct wdt_priv {
 	bool running;
 	/* No autostart */
 	bool noautostart;
+
+	struct cyclic_info *cyclic;
 };
 
+static void wdt_cyclic(void *ctx)
+{
+	struct udevice *dev = ctx;
+	struct wdt_priv *priv;
+
+	if (!device_active(dev))
+		return;
+
+	priv = dev_get_uclass_priv(dev);
+	if (!priv->running)
+		return;
+
+	wdt_reset(dev);
+}
+
 static void init_watchdog_dev(struct udevice *dev)
 {
 	struct wdt_priv *priv;
@@ -64,9 +82,6 @@ static void init_watchdog_dev(struct udevice *dev)
 		printf("WDT:   Failed to start %s\n", dev->name);
 		return;
 	}
-
-	printf("WDT:   Started %s with%s servicing (%ds timeout)\n", dev->name,
-	       IS_ENABLED(CONFIG_WATCHDOG) ? "" : "out", priv->timeout);
 }
 
 int initr_watchdog(void)
@@ -105,8 +120,29 @@ int wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
 	ret = ops->start(dev, timeout_ms, flags);
 	if (ret == 0) {
 		struct wdt_priv *priv = dev_get_uclass_priv(dev);
+		char str[16];
 
 		priv->running = true;
+
+		memset(str, 0, 16);
+		if (IS_ENABLED(CONFIG_WATCHDOG)) {
+			/* Register the watchdog driver as a cyclic function */
+			priv->cyclic = cyclic_register(wdt_cyclic,
+						       priv->reset_period * 1000,
+						       dev->name, dev);
+			if (!priv->cyclic) {
+				printf("cyclic_register for %s failed\n",
+				       dev->name);
+				return -ENODEV;
+			} else {
+				snprintf(str, 16, "every %ldms",
+					 priv->reset_period);
+			}
+		}
+
+		printf("WDT:   Started %s with%s servicing %s (%ds timeout)\n",
+		       dev->name, IS_ENABLED(CONFIG_WATCHDOG) ? "" : "out",
+		       str, priv->timeout);
 	}
 
 	return ret;
@@ -194,37 +230,10 @@ int wdt_expire_now(struct udevice *dev, ulong flags)
  */
 void watchdog_reset(void)
 {
-	struct wdt_priv *priv;
-	struct udevice *dev;
-	struct uclass *uc;
-	ulong now;
-
-	/* Exit if GD is not ready or watchdog is not initialized yet */
-	if (!gd || !(gd->flags & GD_FLG_WDT_READY))
-		return;
-
-	if (uclass_get(UCLASS_WDT, &uc))
-		return;
-
 	/*
-	 * All devices bound to the wdt uclass should have been probed
+	 * Empty function for now. The actual WDT handling is now done in
-	 * in initr_watchdog(). But just in case something went wrong,
+	 * the cyclic function instead.
-	 * check device_active() before accessing the uclass private
-	 * data.
 	 */
-	uclass_foreach_dev(dev, uc) {
-		if (!device_active(dev))
-			continue;
-		priv = dev_get_uclass_priv(dev);
-		if (!priv->running)
-			continue;
-		/* Do not reset the watchdog too often */
-		now = get_timer(0);
-		if (time_after_eq(now, priv->next_reset)) {
-			priv->next_reset = now + priv->reset_period;
-			wdt_reset(dev);
-		}
-	}
 }
 #endif