watchdog: Add support for keepalives triggered by infrastructure

index 6aaefbad303e..06171c73daf5 100644
@@ -51,7 +51,7 @@ static struct watchdog_device *old_wdd;
 
 /*
  *	watchdog_ping: ping the watchdog.
- *	@wddev: the watchdog device to ping
+ *	@wdd: the watchdog device to ping
  *
  *	If the watchdog has no own ping operation then it needs to be
  *	restarted via the start operation. This wrapper function does

@@ -59,65 +59,65 @@ static struct watchdog_device *old_wdd;
  *	We only ping when the watchdog device is running.
  */
 
-static int watchdog_ping(struct watchdog_device *wddev)
+static int watchdog_ping(struct watchdog_device *wdd)
 {
 	int err = 0;
 
-	mutex_lock(&wddev->lock);
+	mutex_lock(&wdd->lock);
 
-	if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+	if (test_bit(WDOG_UNREGISTERED, &wdd->status)) {
 		err = -ENODEV;
 		goto out_ping;
 	}
 
-	if (!watchdog_active(wddev))
+	if (!watchdog_active(wdd))
 		goto out_ping;
 
-	if (wddev->ops->ping)
-		err = wddev->ops->ping(wddev);  /* ping the watchdog */
+	if (wdd->ops->ping)
+		err = wdd->ops->ping(wdd);	/* ping the watchdog */
 	else
-		err = wddev->ops->start(wddev); /* restart watchdog */
+		err = wdd->ops->start(wdd);	/* restart watchdog */
 
 out_ping:
-	mutex_unlock(&wddev->lock);
+	mutex_unlock(&wdd->lock);
 	return err;
 }
 
 /*
  *	watchdog_start: wrapper to start the watchdog.
- *	@wddev: the watchdog device to start
+ *	@wdd: the watchdog device to start
  *
  *	Start the watchdog if it is not active and mark it active.
  *	This function returns zero on success or a negative errno code for
  *	failure.
  */
 
-static int watchdog_start(struct watchdog_device *wddev)
+static int watchdog_start(struct watchdog_device *wdd)
 {
 	int err = 0;
 
-	mutex_lock(&wddev->lock);
+	mutex_lock(&wdd->lock);
 
-	if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+	if (test_bit(WDOG_UNREGISTERED, &wdd->status)) {
 		err = -ENODEV;
 		goto out_start;
 	}
 
-	if (watchdog_active(wddev))
+	if (watchdog_active(wdd))
 		goto out_start;
 
-	err = wddev->ops->start(wddev);
+	err = wdd->ops->start(wdd);
 	if (err == 0)
-		set_bit(WDOG_ACTIVE, &wddev->status);
+		set_bit(WDOG_ACTIVE, &wdd->status);
 
 out_start:
-	mutex_unlock(&wddev->lock);
+	mutex_unlock(&wdd->lock);
 	return err;
 }
 
 /*
  *	watchdog_stop: wrapper to stop the watchdog.
- *	@wddev: the watchdog device to stop
+ *	@wdd: the watchdog device to stop
  *
  *	Stop the watchdog if it is still active and unmark it active.
  *	This function returns zero on success or a negative errno code for

@@ -125,155 +125,154 @@ out_start:
  *	If the 'nowayout' feature was set, the watchdog cannot be stopped.
  */
 
-static int watchdog_stop(struct watchdog_device *wddev)
+static int watchdog_stop(struct watchdog_device *wdd)
 {
 	int err = 0;
 
-	mutex_lock(&wddev->lock);
+	mutex_lock(&wdd->lock);
 
-	if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+	if (test_bit(WDOG_UNREGISTERED, &wdd->status)) {
 		err = -ENODEV;
 		goto out_stop;
 	}
 
-	if (!watchdog_active(wddev))
+	if (!watchdog_active(wdd))
 		goto out_stop;
 
-	if (test_bit(WDOG_NO_WAY_OUT, &wddev->status)) {
-		dev_info(wddev->dev, "nowayout prevents watchdog being stopped!\n");
+	if (test_bit(WDOG_NO_WAY_OUT, &wdd->status)) {
+		dev_info(wdd->dev, "nowayout prevents watchdog being stopped!\n");
 		err = -EBUSY;
 		goto out_stop;
 	}
 
-	err = wddev->ops->stop(wddev);
+	err = wdd->ops->stop(wdd);
 	if (err == 0)
-		clear_bit(WDOG_ACTIVE, &wddev->status);
+		clear_bit(WDOG_ACTIVE, &wdd->status);
 
 out_stop:
-	mutex_unlock(&wddev->lock);
+	mutex_unlock(&wdd->lock);
 	return err;
 }
 
 /*
  *	watchdog_get_status: wrapper to get the watchdog status
- *	@wddev: the watchdog device to get the status from
+ *	@wdd: the watchdog device to get the status from
  *	@status: the status of the watchdog device
  *
  *	Get the watchdog's status flags.
  */
 
-static int watchdog_get_status(struct watchdog_device *wddev,
+static int watchdog_get_status(struct watchdog_device *wdd,
 							unsigned int *status)
 {
 	int err = 0;
 
 	*status = 0;
-	if (!wddev->ops->status)
+	if (!wdd->ops->status)
 		return -EOPNOTSUPP;
 
-	mutex_lock(&wddev->lock);
+	mutex_lock(&wdd->lock);
 
-	if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+	if (test_bit(WDOG_UNREGISTERED, &wdd->status)) {
 		err = -ENODEV;
 		goto out_status;
 	}
 
-	*status = wddev->ops->status(wddev);
+	*status = wdd->ops->status(wdd);
 
 out_status:
-	mutex_unlock(&wddev->lock);
+	mutex_unlock(&wdd->lock);
 	return err;
 }
 
 /*
  *	watchdog_set_timeout: set the watchdog timer timeout
- *	@wddev: the watchdog device to set the timeout for
+ *	@wdd: the watchdog device to set the timeout for
  *	@timeout: timeout to set in seconds
  */
 
-static int watchdog_set_timeout(struct watchdog_device *wddev,
+static int watchdog_set_timeout(struct watchdog_device *wdd,
 							unsigned int timeout)
 {
 	int err;
 
-	if ((wddev->ops->set_timeout == NULL) ||
-	    !(wddev->info->options & WDIOF_SETTIMEOUT))
+	if (!wdd->ops->set_timeout || !(wdd->info->options & WDIOF_SETTIMEOUT))
 		return -EOPNOTSUPP;
 
-	if (watchdog_timeout_invalid(wddev, timeout))
+	if (watchdog_timeout_invalid(wdd, timeout))
 		return -EINVAL;
 
-	mutex_lock(&wddev->lock);
+	mutex_lock(&wdd->lock);
 
-	if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+	if (test_bit(WDOG_UNREGISTERED, &wdd->status)) {
 		err = -ENODEV;
 		goto out_timeout;
 	}
 
-	err = wddev->ops->set_timeout(wddev, timeout);
+	err = wdd->ops->set_timeout(wdd, timeout);
 
 out_timeout:
-	mutex_unlock(&wddev->lock);
+	mutex_unlock(&wdd->lock);
 	return err;
 }
 
 /*
  *	watchdog_get_timeleft: wrapper to get the time left before a reboot
- *	@wddev: the watchdog device to get the remaining time from
+ *	@wdd: the watchdog device to get the remaining time from
  *	@timeleft: the time that's left
  *
  *	Get the time before a watchdog will reboot (if not pinged).
  */
 
-static int watchdog_get_timeleft(struct watchdog_device *wddev,
+static int watchdog_get_timeleft(struct watchdog_device *wdd,
 							unsigned int *timeleft)
 {
 	int err = 0;
 
 	*timeleft = 0;
-	if (!wddev->ops->get_timeleft)
+	if (!wdd->ops->get_timeleft)
 		return -EOPNOTSUPP;
 
-	mutex_lock(&wddev->lock);
+	mutex_lock(&wdd->lock);
 
-	if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+	if (test_bit(WDOG_UNREGISTERED, &wdd->status)) {
 		err = -ENODEV;
 		goto out_timeleft;
 	}
 
-	*timeleft = wddev->ops->get_timeleft(wddev);
+	*timeleft = wdd->ops->get_timeleft(wdd);
 
 out_timeleft:
-	mutex_unlock(&wddev->lock);
+	mutex_unlock(&wdd->lock);
 	return err;
 }
 
 /*
  *	watchdog_ioctl_op: call the watchdog drivers ioctl op if defined
- *	@wddev: the watchdog device to do the ioctl on
+ *	@wdd: the watchdog device to do the ioctl on
  *	@cmd: watchdog command
  *	@arg: argument pointer
  */
 
-static int watchdog_ioctl_op(struct watchdog_device *wddev, unsigned int cmd,
+static int watchdog_ioctl_op(struct watchdog_device *wdd, unsigned int cmd,
 							unsigned long arg)
 {
 	int err;
 
-	if (!wddev->ops->ioctl)
+	if (!wdd->ops->ioctl)
 		return -ENOIOCTLCMD;
 
-	mutex_lock(&wddev->lock);
+	mutex_lock(&wdd->lock);
 
-	if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+	if (test_bit(WDOG_UNREGISTERED, &wdd->status)) {
 		err = -ENODEV;
 		goto out_ioctl;
 	}
 
-	err = wddev->ops->ioctl(wddev, cmd, arg);
+	err = wdd->ops->ioctl(wdd, cmd, arg);
 
 out_ioctl:
-	mutex_unlock(&wddev->lock);
+	mutex_unlock(&wdd->lock);
 	return err;
 }
 

@@ -513,43 +512,43 @@ static struct miscdevice watchdog_miscdev = {
 
 /*
  *	watchdog_dev_register: register a watchdog device
- *	@watchdog: watchdog device
+ *	@wdd: watchdog device
  *
  *	Register a watchdog device including handling the legacy
  *	/dev/watchdog node. /dev/watchdog is actually a miscdevice and
  *	thus we set it up like that.
  */
 
-int watchdog_dev_register(struct watchdog_device *watchdog)
+int watchdog_dev_register(struct watchdog_device *wdd)
 {
 	int err, devno;
 
-	if (watchdog->id == 0) {
-		old_wdd = watchdog;
-		watchdog_miscdev.parent = watchdog->parent;
+	if (wdd->id == 0) {
+		old_wdd = wdd;
+		watchdog_miscdev.parent = wdd->parent;
 		err = misc_register(&watchdog_miscdev);
 		if (err != 0) {
 			pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n",
-				watchdog->info->identity, WATCHDOG_MINOR, err);
+				wdd->info->identity, WATCHDOG_MINOR, err);
 			if (err == -EBUSY)
 				pr_err("%s: a legacy watchdog module is probably present.\n",
-					watchdog->info->identity);
+					wdd->info->identity);
 			old_wdd = NULL;
 			return err;
 		}
 	}
 
 	/* Fill in the data structures */
-	devno = MKDEV(MAJOR(watchdog_devt), watchdog->id);
-	cdev_init(&watchdog->cdev, &watchdog_fops);
-	watchdog->cdev.owner = watchdog->ops->owner;
+	devno = MKDEV(MAJOR(watchdog_devt), wdd->id);
+	cdev_init(&wdd->cdev, &watchdog_fops);
+	wdd->cdev.owner = wdd->ops->owner;
 
 	/* Add the device */
-	err  = cdev_add(&watchdog->cdev, devno, 1);
+	err  = cdev_add(&wdd->cdev, devno, 1);
 	if (err) {
 		pr_err("watchdog%d unable to add device %d:%d\n",
-			watchdog->id,  MAJOR(watchdog_devt), watchdog->id);
-		if (watchdog->id == 0) {
+			wdd->id,  MAJOR(watchdog_devt), wdd->id);
+		if (wdd->id == 0) {
 			misc_deregister(&watchdog_miscdev);
 			old_wdd = NULL;
 		}

@@ -564,14 +563,14 @@ int watchdog_dev_register(struct watchdog_device *watchdog)
  *	Unregister the watchdog and if needed the legacy /dev/watchdog device.
  */
 
-int watchdog_dev_unregister(struct watchdog_device *watchdog)
+int watchdog_dev_unregister(struct watchdog_device *wdd)
 {
-	mutex_lock(&watchdog->lock);
-	set_bit(WDOG_UNREGISTERED, &watchdog->status);
-	mutex_unlock(&watchdog->lock);
+	mutex_lock(&wdd->lock);
+	set_bit(WDOG_UNREGISTERED, &wdd->status);
+	mutex_unlock(&wdd->lock);
 
-	cdev_del(&watchdog->cdev);
-	if (watchdog->id == 0) {
+	cdev_del(&wdd->cdev);
+	if (wdd->id == 0) {
 		misc_deregister(&watchdog_miscdev);
 		old_wdd = NULL;
 	}

216 lines not on this page · raw message

index f47feada5b42..0e0cf36485c1 100644
@@ -12,6 +12,7 @@
 #include <linux/bitops.h>
 #include <linux/device.h>
 #include <linux/cdev.h>
+#include <linux/workqueue.h>
 #include <uapi/linux/watchdog.h>
 
 struct watchdog_ops;

@@ -59,14 +60,21 @@ struct watchdog_ops {
  * @info:	Pointer to a watchdog_info structure.
  * @ops:	Pointer to the list of watchdog operations.
  * @bootstatus:	Status of the watchdog device at boot.
- * @timeout:	The watchdog devices timeout value.
- * @min_timeout:The watchdog devices minimum timeout value.
- * @max_timeout:The watchdog devices maximum timeout value.
+ * @timeout:	The watchdog devices timeout value, in seconds.
+ * @min_timeout:The watchdog devices minimum timeout value, in seconds.
+ * @max_timeout:The watchdog devices maximum timeout value, in seconds.
+ * @max_hw_timeout_ms:
+ *		Hardware limit for maximum timeout, in milli-seconds,
+ *		if different from max_timeout.
  * @driver-data:Pointer to the drivers private data.
- * @lock:	Lock for watchdog core internal use only.
  * @status:	Field that contains the devices internal status bits.
- * @deferred: entry in wtd_deferred_reg_list which is used to
- *			   register early initialized watchdogs.
+ * @lock:	Lock for watchdog core internal use only.
+ * @last_keepalive:
+ *		Time of most recent keepalive triggered from user space,
+ *		in jiffies (watchdog core internal).
+ * @work:	Data structure for worker function (watchdog core internal).
+ * @deferred:	entry in wtd_deferred_reg_list which is used to
+ *		register early initialized watchdogs.
  *
  * The watchdog_device structure contains all information about a
  * watchdog timer device.

@@ -88,8 +96,8 @@ struct watchdog_device {
 	unsigned int timeout;
 	unsigned int min_timeout;
 	unsigned int max_timeout;
+	unsigned int max_hw_timeout_ms;
 	void *driver_data;
-	struct mutex lock;
 	unsigned long status;
 /* Bit numbers for status flags */
 #define WDOG_ACTIVE		0	/* Is the watchdog running/active */

@@ -97,6 +105,10 @@ struct watchdog_device {
 #define WDOG_ALLOW_RELEASE	2	/* Did we receive the magic char ? */
 #define WDOG_NO_WAY_OUT		3	/* Is 'nowayout' feature set ? */
 #define WDOG_UNREGISTERED	4	/* Has the device been unregistered */
+	/* the following variables are for internal use only */
+	struct mutex lock;
+	unsigned long last_keepalive;
+	struct delayed_work work;
 	struct list_head deferred;
 };
 

index 1a8059455413..b38d1b7ae10e 100644
@@ -145,7 +145,7 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
 		return -EINVAL;
 
 	/* Mandatory operations need to be supported */
-	if (wdd->ops->start == NULL || wdd->ops->stop == NULL)
+	if (!wdd->ops->start)
 		return -EINVAL;
 
 	watchdog_check_min_max_timeout(wdd);

index c04ba1a98cc8..676e233d5e7b 100644
@@ -59,7 +59,8 @@ static inline bool watchdog_need_worker(struct watchdog_device *wdd)
 	unsigned int m = wdd->max_timeout * 1000;
 	unsigned int t = wdd->timeout * 1000;
 
-	return watchdog_active(wdd) && hm && (!m || hm < m) && t > hm;
+	return (watchdog_active(wdd) && hm && (!m || hm < m) && t > hm) ||
+	       (t && !watchdog_active(wdd) && watchdog_running(wdd));
 }
 
 static unsigned long watchdog_next_keepalive(struct watchdog_device *wdd)

@@ -73,6 +74,9 @@ static unsigned long watchdog_next_keepalive(struct watchdog_device *wdd)
 
 	tj = msecs_to_jiffies(t / 2);
 
+	if (!watchdog_active(wdd))
+		return tj;
+
 	/*
 	 * Ensure that the watchdog times out wdd->timeout seconds
 	 * after the most recent keepalive sent from user space.

@@ -112,7 +116,7 @@ static int _watchdog_ping(struct watchdog_device *wdd)
 	if (test_bit(WDOG_UNREGISTERED, &wdd->status))
 		return -ENODEV;
 
-	if (!watchdog_active(wdd))
+	if (!watchdog_active(wdd) && !watchdog_running(wdd))
 		return 0;
 
 	if (wdd->ops->ping)

@@ -223,7 +227,11 @@ static int watchdog_stop(struct watchdog_device *wdd)
 		goto out_stop;
 	}
 
-	err = wdd->ops->stop(wdd);
+	if (wdd->ops->stop)
+		err = wdd->ops->stop(wdd);
+	else
+		set_bit(WDOG_RUNNING, &wdd->status);
+
 	if (err == 0) {
 		clear_bit(WDOG_ACTIVE, &wdd->status);
 		watchdog_update_worker(wdd, true, false);

@@ -508,7 +516,7 @@ static int watchdog_open(struct inode *inode, struct file *file)
 	 * If the /dev/watchdog device is open, we don't want the module
 	 * to be unloaded.
 	 */
-	if (!try_module_get(wdd->ops->owner))
+	if (!watchdog_running(wdd) && !try_module_get(wdd->ops->owner))
 		goto out;
 
 	err = watchdog_start(wdd);

@@ -565,10 +573,15 @@ static int watchdog_release(struct inode *inode, struct file *file)
 		watchdog_ping(wdd);
 	}
 
-	cancel_delayed_work_sync(&wdd->work);
+	watchdog_update_worker(wdd, true, true);
 
-	/* Allow the owner module to be unloaded again */
-	module_put(wdd->ops->owner);
+	/*
+	 * Allow the owner module to be unloaded again unless the watchdog
+	 * is still running. If the watchdog is still running, it can not
+	 * be stopped, and its driver must not be unloaded.
+	 */
+	if (!watchdog_running(wdd))
+		module_put(wdd->ops->owner);
 
 	/* make sure that /dev/watchdog can be re-opened */
 	clear_bit(WDOG_DEV_OPEN, &wdd->status);

@@ -644,8 +657,19 @@ int watchdog_dev_register(struct watchdog_device *wdd)
 			misc_deregister(&watchdog_miscdev);
 			old_wdd = NULL;
 		}
+		return err;
 	}
-	return err;
+
+	/*
+	 * If the watchdog is running, prevent its driver from being unloaded,
+	 * and schedule an immediate ping.
+	 */
+	if (watchdog_running(wdd)) {
+		__module_get(wdd->ops->owner);
+		queue_delayed_work(watchdog_wq, &wdd->work, 0);
+	}
+
+	return 0;
 }
 
 /*

index 0e0cf36485c1..5b21bf8a8a32 100644
@@ -105,6 +105,7 @@ struct watchdog_device {
 #define WDOG_ALLOW_RELEASE	2	/* Did we receive the magic char ? */
 #define WDOG_NO_WAY_OUT		3	/* Is 'nowayout' feature set ? */
 #define WDOG_UNREGISTERED	4	/* Has the device been unregistered */
+#define WDOG_RUNNING		5	/* True if HW watchdog running */
 	/* the following variables are for internal use only */
 	struct mutex lock;
 	unsigned long last_keepalive;

@@ -121,6 +122,12 @@ static inline bool watchdog_active(struct watchdog_device *wdd)
 	return test_bit(WDOG_ACTIVE, &wdd->status);
 }
 
+/* Use the following function to check whether or not the watchdog is running */
+static inline bool watchdog_running(struct watchdog_device *wdd)
+{
+	return test_bit(WDOG_RUNNING, &wdd->status);
+}
+
 /* Use the following function to set the nowayout feature */
 static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout)
 {

index 676e233d5e7b..752de264a244 100644
@@ -282,9 +282,9 @@ out_status:
 static int watchdog_set_timeout(struct watchdog_device *wdd,
 							unsigned int timeout)
 {
-	int err;
+	int err = 0;
 
-	if (!wdd->ops->set_timeout || !(wdd->info->options & WDIOF_SETTIMEOUT))
+	if (!(wdd->info->options & WDIOF_SETTIMEOUT))
 		return -EOPNOTSUPP;
 
 	if (watchdog_timeout_invalid(wdd, timeout))

@@ -297,7 +297,10 @@ static int watchdog_set_timeout(struct watchdog_device *wdd,
 		goto out_timeout;
 	}
 
-	err = wdd->ops->set_timeout(wdd, timeout);
+	if (wdd->ops->set_timeout)
+		err = wdd->ops->set_timeout(wdd, timeout);
+	else
+		wdd->timeout = timeout;
 
 	watchdog_update_worker(wdd, true, false);
 

index 0bb1a1d1b170..66feef254661 100644
@@ -25,7 +25,6 @@
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/io.h>
-#include <linux/jiffies.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>

@@ -34,7 +33,6 @@
 #include <linux/platform_device.h>
 #include <linux/reboot.h>
 #include <linux/regmap.h>
-#include <linux/timer.h>
 #include <linux/watchdog.h>
 
 #define DRIVER_NAME "imx2-wdt"

@@ -62,7 +60,6 @@
 struct imx2_wdt_device {
 	struct clk *clk;
 	struct regmap *regmap;
-	struct timer_list timer;	/* Pings the watchdog when closed */
 	struct watchdog_device wdog;
 	struct notifier_block restart_handler;
 };

@@ -151,16 +148,6 @@ static int imx2_wdt_ping(struct watchdog_device *wdog)
 	return 0;
 }
 
-static void imx2_wdt_timer_ping(unsigned long arg)
-{
-	struct watchdog_device *wdog = (struct watchdog_device *)arg;
-	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
-
-	/* ping it every wdog->timeout / 2 seconds to prevent reboot */
-	imx2_wdt_ping(wdog);
-	mod_timer(&wdev->timer, jiffies + wdog->timeout * HZ / 2);
-}
-
 static int imx2_wdt_set_timeout(struct watchdog_device *wdog,
 				unsigned int new_timeout)
 {

@@ -177,40 +164,19 @@ static int imx2_wdt_start(struct watchdog_device *wdog)
 {
 	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
 
-	if (imx2_wdt_is_running(wdev)) {
-		/* delete the timer that pings the watchdog after close */
-		del_timer_sync(&wdev->timer);
+	if (imx2_wdt_is_running(wdev))
 		imx2_wdt_set_timeout(wdog, wdog->timeout);
-	} else
+	else
 		imx2_wdt_setup(wdog);
 
-	return imx2_wdt_ping(wdog);
-}
-
-static int imx2_wdt_stop(struct watchdog_device *wdog)
-{
-	/*
-	 * We don't need a clk_disable, it cannot be disabled once started.
-	 * We use a timer to ping the watchdog while /dev/watchdog is closed
-	 */
-	imx2_wdt_timer_ping((unsigned long)wdog);
-	return 0;
-}
-
-static inline void imx2_wdt_ping_if_active(struct watchdog_device *wdog)
-{
-	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+	set_bit(WDOG_RUNNING, &wdog->status);
 
-	if (imx2_wdt_is_running(wdev)) {
-		imx2_wdt_set_timeout(wdog, wdog->timeout);
-		imx2_wdt_timer_ping((unsigned long)wdog);
-	}
+	return imx2_wdt_ping(wdog);
 }
 
 static const struct watchdog_ops imx2_wdt_ops = {
 	.owner = THIS_MODULE,
 	.start = imx2_wdt_start,
-	.stop = imx2_wdt_stop,
 	.ping = imx2_wdt_ping,
 	.set_timeout = imx2_wdt_set_timeout,
 };

@@ -277,9 +243,10 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
 	watchdog_set_nowayout(wdog, nowayout);
 	watchdog_init_timeout(wdog, timeout, &pdev->dev);
 
-	setup_timer(&wdev->timer, imx2_wdt_timer_ping, (unsigned long)wdog);
-
-	imx2_wdt_ping_if_active(wdog);
+	if (imx2_wdt_is_running(wdev)) {
+		imx2_wdt_set_timeout(wdog, wdog->timeout);
+		set_bit(WDOG_RUNNING, &wdog->status);
+	}
 
 	/*
 	 * Disable the watchdog power down counter at boot. Otherwise the power

@@ -320,7 +287,6 @@ static int __exit imx2_wdt_remove(struct platform_device *pdev)
 	watchdog_unregister_device(wdog);
 
 	if (imx2_wdt_is_running(wdev)) {
-		del_timer_sync(&wdev->timer);
 		imx2_wdt_ping(wdog);
 		dev_crit(&pdev->dev, "Device removed: Expect reboot!\n");
 	}

@@ -334,10 +300,9 @@ static void imx2_wdt_shutdown(struct platform_device *pdev)
 
 	if (imx2_wdt_is_running(wdev)) {
 		/*
-		 * We are running, we need to delete the timer but will
-		 * give max timeout before reboot will take place
+		 * We are running, configure max timeout before reboot
+		 * will take place.
 		 */
-		del_timer_sync(&wdev->timer);
 		imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME);
 		imx2_wdt_ping(wdog);
 		dev_crit(&pdev->dev, "Device shutdown: Expect reboot!\n");

@@ -355,10 +320,6 @@ static int imx2_wdt_suspend(struct device *dev)
 	if (imx2_wdt_is_running(wdev)) {
 		imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME);
 		imx2_wdt_ping(wdog);
-
-		/* The watchdog is not active */
-		if (!watchdog_active(wdog))
-			del_timer_sync(&wdev->timer);
 	}
 
 	clk_disable_unprepare(wdev->clk);

@@ -384,19 +345,10 @@ static int imx2_wdt_resume(struct device *dev)
 		 * watchdog again.
 		 */
 		imx2_wdt_setup(wdog);
+	}
+	if (imx2_wdt_is_running(wdev)) {
 		imx2_wdt_set_timeout(wdog, wdog->timeout);
 		imx2_wdt_ping(wdog);
-	} else if (imx2_wdt_is_running(wdev)) {
-		/* Resuming from non-deep sleep state. */
-		imx2_wdt_set_timeout(wdog, wdog->timeout);
-		imx2_wdt_ping(wdog);
-		/*
-		 * But the watchdog is not active, then start
-		 * the timer again.
-		 */
-		if (!watchdog_active(wdog))
-			mod_timer(&wdev->timer,
-				  jiffies + wdog->timeout * HZ / 2);
 	}
 
 	return 0;

index b7c68e275aeb..ce2982a7670c 100644
@@ -28,69 +28,22 @@
 /* Watchdog timer values in seconds */
 #define RETU_WDT_MAX_TIMER	63
 
-struct retu_wdt_dev {
-	struct retu_dev		*rdev;
-	struct device		*dev;
-	struct delayed_work	ping_work;
-};
-
-/*
- * Since Retu watchdog cannot be disabled in hardware, we must kick it
- * with a timer until userspace watchdog software takes over. If
- * CONFIG_WATCHDOG_NOWAYOUT is set, we never start the feeding.
- */
-static void retu_wdt_ping_enable(struct retu_wdt_dev *wdev)
-{
-	retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
-	schedule_delayed_work(&wdev->ping_work,
-			round_jiffies_relative(RETU_WDT_MAX_TIMER * HZ / 2));
-}
-
-static void retu_wdt_ping_disable(struct retu_wdt_dev *wdev)
-{
-	retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
-	cancel_delayed_work_sync(&wdev->ping_work);
-}
-
-static void retu_wdt_ping_work(struct work_struct *work)
-{
-	struct retu_wdt_dev *wdev = container_of(to_delayed_work(work),
-						struct retu_wdt_dev, ping_work);
-	retu_wdt_ping_enable(wdev);
-}
-
 static int retu_wdt_start(struct watchdog_device *wdog)
 {
-	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
+	struct retu_dev *rdev = watchdog_get_drvdata(wdog);
 
-	retu_wdt_ping_disable(wdev);
+	set_bit(WDOG_RUNNING, &wdog->status);
 
-	return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
-}
-
-static int retu_wdt_stop(struct watchdog_device *wdog)
-{
-	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
-
-	retu_wdt_ping_enable(wdev);
-
-	return 0;
-}
-
-static int retu_wdt_ping(struct watchdog_device *wdog)
-{
-	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
-
-	return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
+	return retu_write(rdev, RETU_REG_WATCHDOG, wdog->timeout);
 }
 
 static int retu_wdt_set_timeout(struct watchdog_device *wdog,
 				unsigned int timeout)
 {
-	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
+	struct retu_dev *rdev = watchdog_get_drvdata(wdog);
 
 	wdog->timeout = timeout;
-	return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
+	return retu_write(rdev, RETU_REG_WATCHDOG, wdog->timeout);
 }
 
 static const struct watchdog_info retu_wdt_info = {

@@ -101,8 +54,6 @@ static const struct watchdog_info retu_wdt_info = {
 static const struct watchdog_ops retu_wdt_ops = {
 	.owner		= THIS_MODULE,
 	.start		= retu_wdt_start,
-	.stop		= retu_wdt_stop,
-	.ping		= retu_wdt_ping,
 	.set_timeout	= retu_wdt_set_timeout,
 };
 

@@ -111,39 +62,26 @@ static int retu_wdt_probe(struct platform_device *pdev)
 	struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
 	bool nowayout = WATCHDOG_NOWAYOUT;
 	struct watchdog_device *retu_wdt;
-	struct retu_wdt_dev *wdev;
 	int ret;
 
 	retu_wdt = devm_kzalloc(&pdev->dev, sizeof(*retu_wdt), GFP_KERNEL);
 	if (!retu_wdt)
 		return -ENOMEM;
 
-	wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
-	if (!wdev)
-		return -ENOMEM;
-
 	retu_wdt->info		= &retu_wdt_info;
 	retu_wdt->ops		= &retu_wdt_ops;
 	retu_wdt->timeout	= RETU_WDT_MAX_TIMER;
 	retu_wdt->min_timeout	= 0;
 	retu_wdt->max_timeout	= RETU_WDT_MAX_TIMER;
 
-	watchdog_set_drvdata(retu_wdt, wdev);
+	watchdog_set_drvdata(retu_wdt, rdev);
 	watchdog_set_nowayout(retu_wdt, nowayout);
 
-	wdev->rdev		= rdev;
-	wdev->dev		= &pdev->dev;
-
-	INIT_DELAYED_WORK(&wdev->ping_work, retu_wdt_ping_work);
-
 	ret = watchdog_register_device(retu_wdt);
 	if (ret < 0)
 		return ret;
 
-	if (nowayout)
-		retu_wdt_ping(retu_wdt);
-	else
-		retu_wdt_ping_enable(wdev);
+	retu_wdt_start(retu_wdt);
 
 	platform_set_drvdata(pdev, retu_wdt);
 

@@ -153,10 +91,8 @@ static int retu_wdt_probe(struct platform_device *pdev)
 static int retu_wdt_remove(struct platform_device *pdev)
 {
 	struct watchdog_device *wdog = platform_get_drvdata(pdev);
-	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
 
 	watchdog_unregister_device(wdog);
-	cancel_delayed_work_sync(&wdev->ping_work);
 
 	return 0;
 }

index 1687cc2d7122..cbbdae440bfa 100644
@@ -32,12 +32,8 @@ struct gpio_wdt_priv {
 	bool			active_low;
 	bool			state;
 	bool			always_running;
-	bool			armed;
 	unsigned int		hw_algo;
-	unsigned int		hw_margin;
-	unsigned long		last_jiffies;
 	struct notifier_block	notifier;
-	struct timer_list	timer;
 	struct watchdog_device	wdd;
 };
 

@@ -50,20 +46,12 @@ static void gpio_wdt_disable(struct gpio_wdt_priv *priv)
 		gpio_direction_input(priv->gpio);
 }
 
-static void gpio_wdt_start_impl(struct gpio_wdt_priv *priv)
-{
-	priv->state = priv->active_low;
-	gpio_direction_output(priv->gpio, priv->state);
-	priv->last_jiffies = jiffies;
-	mod_timer(&priv->timer, priv->last_jiffies + priv->hw_margin);
-}
-
 static int gpio_wdt_start(struct watchdog_device *wdd)
 {
 	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
 
-	gpio_wdt_start_impl(priv);
-	priv->armed = true;
+	priv->state = priv->active_low;
+	gpio_direction_output(priv->gpio, priv->state);
 
 	return 0;
 }

@@ -72,10 +60,9 @@ static int gpio_wdt_stop(struct watchdog_device *wdd)
 {
 	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
 
-	priv->armed = false;
 	if (!priv->always_running) {
-		mod_timer(&priv->timer, 0);
 		gpio_wdt_disable(priv);
+		clear_bit(WDOG_RUNNING, &priv->wdd.status);
 	}
 
 	return 0;

@@ -85,32 +72,6 @@ static int gpio_wdt_ping(struct watchdog_device *wdd)
 {
 	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
 
-	priv->last_jiffies = jiffies;
-
-	return 0;
-}
-
-static int gpio_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
-{
-	wdd->timeout = t;
-
-	return gpio_wdt_ping(wdd);
-}
-
-static void gpio_wdt_hwping(unsigned long data)
-{
-	struct watchdog_device *wdd = (struct watchdog_device *)data;
-	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
-
-	if (priv->armed && time_after(jiffies, priv->last_jiffies +
-				      msecs_to_jiffies(wdd->timeout * 1000))) {
-		dev_crit(wdd->dev, "Timer expired. System will reboot soon!\n");
-		return;
-	}
-
-	/* Restart timer */
-	mod_timer(&priv->timer, jiffies + priv->hw_margin);
-
 	switch (priv->hw_algo) {
 	case HW_ALGO_TOGGLE:
 		/* Toggle output pin */

@@ -124,6 +85,8 @@ static void gpio_wdt_hwping(unsigned long data)
 		gpio_set_value_cansleep(priv->gpio, priv->active_low);
 		break;
 	}
+
+	return 0;
 }
 
 static int gpio_wdt_notify_sys(struct notifier_block *nb, unsigned long code,

@@ -132,12 +95,10 @@ static int gpio_wdt_notify_sys(struct notifier_block *nb, unsigned long code,
 	struct gpio_wdt_priv *priv = container_of(nb, struct gpio_wdt_priv,
 						  notifier);
 
-	mod_timer(&priv->timer, 0);
-
 	switch (code) {
 	case SYS_HALT:
 	case SYS_POWER_OFF:
-		gpio_wdt_disable(priv);
+		gpio_wdt_stop(&priv->wdd);
 		break;
 	default:
 		break;

@@ -157,7 +118,6 @@ static const struct watchdog_ops gpio_wdt_ops = {
 	.start		= gpio_wdt_start,
 	.stop		= gpio_wdt_stop,
 	.ping		= gpio_wdt_ping,
-	.set_timeout	= gpio_wdt_set_timeout,
 };
 
 static int gpio_wdt_probe(struct platform_device *pdev)

@@ -205,9 +165,6 @@ static int gpio_wdt_probe(struct platform_device *pdev)
 	if (hw_margin < 2 || hw_margin > 65535)
 		return -EINVAL;
 
-	/* Use safe value (1/2 of real timeout) */
-	priv->hw_margin = msecs_to_jiffies(hw_margin / 2);
-
 	priv->always_running = of_property_read_bool(pdev->dev.of_node,
 						     "always-running");
 

@@ -217,11 +174,15 @@ static int gpio_wdt_probe(struct platform_device *pdev)
 	priv->wdd.ops		= &gpio_wdt_ops;
 	priv->wdd.min_timeout	= SOFT_TIMEOUT_MIN;
 	priv->wdd.max_timeout	= SOFT_TIMEOUT_MAX;
+	priv->wdd.max_hw_timeout_ms = hw_margin;
 
 	if (watchdog_init_timeout(&priv->wdd, 0, &pdev->dev) < 0)
 		priv->wdd.timeout = SOFT_TIMEOUT_DEF;
 
-	setup_timer(&priv->timer, gpio_wdt_hwping, (unsigned long)&priv->wdd);
+	if (priv->always_running) {
+		set_bit(WDOG_RUNNING, &priv->wdd.status);
+		gpio_wdt_start(&priv->wdd);
+	}
 
 	ret = watchdog_register_device(&priv->wdd);
 	if (ret)

@@ -232,9 +193,6 @@ static int gpio_wdt_probe(struct platform_device *pdev)
 	if (ret)
 		goto error_unregister;
 
-	if (priv->always_running)
-		gpio_wdt_start_impl(priv);
-
 	return 0;
 
 error_unregister:

@@ -246,7 +204,6 @@ static int gpio_wdt_remove(struct platform_device *pdev)
 {
 	struct gpio_wdt_priv *priv = platform_get_drvdata(pdev);
 
-	del_timer_sync(&priv->timer);
 	unregister_reboot_notifier(&priv->notifier);
 	watchdog_unregister_device(&priv->wdd);
 

index e4698f7c5f93..0de39b52962c 100644
@@ -29,7 +29,6 @@
 #include <linux/types.h>
 #include <linux/watchdog.h>
 #include <linux/jiffies.h>
-#include <linux/timer.h>
 #include <linux/bitops.h>
 #include <linux/uaccess.h>
 #include <linux/of.h>

@@ -48,8 +47,8 @@
  * use this to convert a watchdog
  * value from/to milliseconds.
  */
-#define ticks_to_hz_rounddown(t)	((((t) + 1) * HZ) >> 8)
-#define ticks_to_hz_roundup(t)		(((((t) + 1) * HZ) + 255) >> 8)
+#define ticks_to_ms_rounddown(t)	((((t) + 1) * 1000) >> 8)
+#define ticks_to_ms_roundup(t)		(((((t) + 1) * 1000) + 255) >> 8)
 #define ticks_to_secs(t)		(((t) + 1) >> 8)
 #define secs_to_ticks(s)		((s) ? (((s) << 8) - 1) : 0)
 

@@ -64,9 +63,6 @@
 /* Hardware timeout in seconds */
 #define WDT_HW_TIMEOUT 2
 
-/* Timer heartbeat (500ms) */
-#define WDT_TIMEOUT	(HZ/2)
-
 /* User land timeout */
 #define WDT_HEARTBEAT 15
 static int heartbeat;

@@ -83,11 +79,8 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
 struct at91wdt {
 	struct watchdog_device wdd;
 	void __iomem *base;
-	unsigned long next_heartbeat;	/* the next_heartbeat for the timer */
-	struct timer_list timer;	/* The timer that pings the watchdog */
 	u32 mr;
 	u32 mr_mask;
-	unsigned long heartbeat;	/* WDT heartbeat in jiffies */
 	bool nowayout;
 	unsigned int irq;
 };

@@ -107,47 +100,13 @@ static irqreturn_t wdt_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-/*
- * Reload the watchdog timer.  (ie, pat the watchdog)
- */
-static inline void at91_wdt_reset(struct at91wdt *wdt)
-{
-	wdt_write(wdt, AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT);
-}
-
-/*
- * Timer tick
- */
-static void at91_ping(unsigned long data)
-{
-	struct at91wdt *wdt = (struct at91wdt *)data;
-	if (time_before(jiffies, wdt->next_heartbeat) ||
-	    !watchdog_active(&wdt->wdd)) {
-		at91_wdt_reset(wdt);
-		mod_timer(&wdt->timer, jiffies + wdt->heartbeat);
-	} else {
-		pr_crit("I will reset your machine !\n");
-	}
-}
-
 static int at91_wdt_start(struct watchdog_device *wdd)
 {
 	struct at91wdt *wdt = to_wdt(wdd);
-	/* calculate when the next userspace timeout will be */
-	wdt->next_heartbeat = jiffies + wdd->timeout * HZ;
-	return 0;
-}
 
-static int at91_wdt_stop(struct watchdog_device *wdd)
-{
-	/* The watchdog timer hardware can not be stopped... */
-	return 0;
-}
+	wdt_write(wdt, AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT);
 
-static int at91_wdt_set_timeout(struct watchdog_device *wdd, unsigned int new_timeout)
-{
-	wdd->timeout = new_timeout;
-	return at91_wdt_start(wdd);
+	return 0;
 }
 
 static int at91_wdt_init(struct platform_device *pdev, struct at91wdt *wdt)

@@ -157,8 +116,8 @@ static int at91_wdt_init(struct platform_device *pdev, struct at91wdt *wdt)
 	u32 value;
 	int err;
 	u32 mask = wdt->mr_mask;
-	unsigned long min_heartbeat = 1;
-	unsigned long max_heartbeat;
+	unsigned int min_timeout = jiffies_to_msecs(1);
+	unsigned int hw_timeout;
 	struct device *dev = &pdev->dev;
 
 	tmp = wdt_read(wdt, AT91_WDT_MR);

@@ -180,31 +139,15 @@ static int at91_wdt_init(struct platform_device *pdev, struct at91wdt *wdt)
 	delta = (tmp & AT91_WDT_WDD) >> 16;
 
 	if (delta < value)
-		min_heartbeat = ticks_to_hz_roundup(value - delta);
+		min_timeout = ticks_to_ms_roundup(value - delta);
 
-	max_heartbeat = ticks_to_hz_rounddown(value);
-	if (!max_heartbeat) {
+	hw_timeout = ticks_to_ms_rounddown(value);
+	if (hw_timeout < min_timeout * 2) {
 		dev_err(dev,
 			"heartbeat is too small for the system to handle it correctly\n");
 		return -EINVAL;
 	}
-
-	/*
-	 * Try to reset the watchdog counter 4 or 2 times more often than
-	 * actually requested, to avoid spurious watchdog reset.
-	 * If this is not possible because of the min_heartbeat value, reset
-	 * it at the min_heartbeat period.
-	 */
-	if ((max_heartbeat / 4) >= min_heartbeat)
-		wdt->heartbeat = max_heartbeat / 4;
-	else if ((max_heartbeat / 2) >= min_heartbeat)
-		wdt->heartbeat = max_heartbeat / 2;
-	else
-		wdt->heartbeat = min_heartbeat;
-
-	if (max_heartbeat < min_heartbeat + 4)
-		dev_warn(dev,
-			 "min heartbeat and max heartbeat might be too close for the system to handle it correctly\n");
+	wdt->wdd.max_hw_timeout_ms = hw_timeout;
 
 	if ((tmp & AT91_WDT_WDFIEN) && wdt->irq) {
 		err = request_irq(wdt->irq, wdt_interrupt,

@@ -220,32 +163,12 @@ static int at91_wdt_init(struct platform_device *pdev, struct at91wdt *wdt)
 			 "watchdog already configured differently (mr = %x expecting %x)\n",
 			 tmp & wdt->mr_mask, wdt->mr & wdt->mr_mask);
 
-	setup_timer(&wdt->timer, at91_ping, (unsigned long)wdt);
-
-	/*
-	 * Use min_heartbeat the first time to avoid spurious watchdog reset:
-	 * we don't know for how long the watchdog counter is running, and
-	 *  - resetting it right now might trigger a watchdog fault reset
-	 *  - waiting for heartbeat time might lead to a watchdog timeout
-	 *    reset
-	 */
-	mod_timer(&wdt->timer, jiffies + min_heartbeat);
-
 	/* Try to set timeout from device tree first */
 	if (watchdog_init_timeout(&wdt->wdd, 0, dev))
 		watchdog_init_timeout(&wdt->wdd, heartbeat, dev);
 	watchdog_set_nowayout(&wdt->wdd, wdt->nowayout);
-	err = watchdog_register_device(&wdt->wdd);
-	if (err)
-		goto out_stop_timer;
-
-	wdt->next_heartbeat = jiffies + wdt->wdd.timeout * HZ;
-
-	return 0;
 
-out_stop_timer:
-	del_timer(&wdt->timer);
-	return err;
+	return watchdog_register_device(&wdt->wdd);
 }
 
 /* ......................................................................... */

@@ -259,8 +182,6 @@ static const struct watchdog_info at91_wdt_info = {
 static const struct watchdog_ops at91_wdt_ops = {
 	.owner =	THIS_MODULE,
 	.start =	at91_wdt_start,
-	.stop =		at91_wdt_stop,
-	.set_timeout =	at91_wdt_set_timeout,
 };
 
 #if defined(CONFIG_OF)

@@ -376,7 +297,6 @@ static int __exit at91wdt_remove(struct platform_device *pdev)
 	watchdog_unregister_device(&wdt->wdd);
 
 	pr_warn("I quit now, hardware will probably reboot!\n");
-	del_timer(&wdt->timer);
 
 	return 0;
 }