mei: wd: decouple and revamp watchdog state machine

Before ME watchdog was exported through standard watchdog interface
it was closed and started together with the mei device.

The major issue is that closing ME watchdog disabled also MEI device,
to fix this the watchdog state machine has to be independent from MEI
state machine.

Signed-off-by: Tomas Winkler <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/misc/mei/init.c

···
 
 	dev->me_clients_num = 0;
 	dev->rd_msg_hdr = 0;
-	dev->stop = false;
 	dev->wd_pending = false;
 
 	/* update the state of the registers after reset */

drivers/misc/mei/interface.h

···
 
 
 int mei_wd_send(struct mei_device *dev);
-int mei_wd_stop(struct mei_device *dev, bool preserve);
+int mei_wd_stop(struct mei_device *dev);
 int mei_wd_host_init(struct mei_device *dev);
 /*
  * mei_watchdog_register  - Registering watchdog interface

drivers/misc/mei/interrupt.c

···
 		}
 	}
 
-	if (dev->stop && !dev->wd_pending) {
-		dev->wd_stopped = true;
+	if (dev->wd_state == MEI_WD_STOPPING) {
+		dev->wd_state = MEI_WD_IDLE;
 		wake_up_interruptible(&dev->wait_stop_wd);
-		return 0;
 	}
 
 	if (dev->extra_write_index) {
···
 
 			dev->wd_pending = false;
 
-			if (dev->wd_timeout)
+			if (dev->wd_state == MEI_WD_RUNNING)
 				*slots -= mei_data2slots(MEI_WD_START_MSG_SIZE);
 			else
 				*slots -= mei_data2slots(MEI_WD_STOP_MSG_SIZE);
 		}
 	}
-	if (dev->stop)
-		return -ENODEV;
 
 	/* complete control write list CB */
 	dev_dbg(&dev->pdev->dev, "complete control write list cb.\n");

drivers/misc/mei/main.c

···
 
 	mutex_lock(&dev->device_lock);
 
-	mei_wd_stop(dev, false);
+	cancel_delayed_work(&dev->timer_work);
+
+	mei_wd_stop(dev);
 
 	mei_device = NULL;
 
···
 	if (!dev)
 		return -ENODEV;
 	mutex_lock(&dev->device_lock);
+
+	cancel_delayed_work(&dev->timer_work);
+
 	/* Stop watchdog if exists */
-	err = mei_wd_stop(dev, true);
+	err = mei_wd_stop(dev);
 	/* Set new mei state */
 	if (dev->dev_state == MEI_DEV_ENABLED ||
 	    dev->dev_state == MEI_DEV_RECOVERING_FROM_RESET) {

drivers/misc/mei/mei_dev.h

···
 #define MEI_WD_MIN_TIMEOUT       120  /* seconds */
 #define MEI_WD_MAX_TIMEOUT     65535  /* seconds */
 
+#define MEI_WD_STOP_TIMEOUT      10 /* msecs */
+
 #define MEI_WD_STATE_INDEPENDENCE_MSG_SENT       (1 << 0)
 
 #define MEI_RD_MSG_BUF_SIZE           (128 * sizeof(u32))
···
 	MEI_FLOW_CONTROL,
 	MEI_READING,
 	MEI_READ_COMPLETE
+};
+
+enum mei_wd_states {
+	MEI_WD_IDLE,
+	MEI_WD_RUNNING,
+	MEI_WD_STOPPING,
 };
 
 /* MEI CB */
···
 	enum mei_dev_state dev_state;
 	enum mei_init_clients_states init_clients_state;
 	u16 init_clients_timer;
-	bool stop;
 	bool need_reset;
 
 	u32 extra_write_index;
···
 	bool mei_host_buffer_is_empty;
 
 	struct mei_cl wd_cl;
+	enum mei_wd_states wd_state;
 	bool wd_interface_reg;
 	bool wd_pending;
-	bool wd_stopped;
-	bool wd_bypass;	/* if false, don't refresh watchdog ME client */
-	u16 wd_timeout;	/* seconds ((wd_data[1] << 8) + wd_data[0]) */
+	u16 wd_timeout;
 	unsigned char wd_data[MEI_WD_START_MSG_SIZE];
 
 

drivers/misc/mei/wd.c

···
 	/* look for WD client and connect to it */
 	dev->wd_cl.state = MEI_FILE_DISCONNECTED;
 	dev->wd_timeout = MEI_WD_DEFAULT_TIMEOUT;
+	dev->wd_state = MEI_WD_IDLE;
 
 	/* find ME WD client */
 	mei_me_cl_update_filext(dev, &dev->wd_cl,
···
  *	-EIO when message send fails
  *	-EINVAL when invalid message is to be sent
  */
-int mei_wd_stop(struct mei_device *dev, bool preserve)
+int mei_wd_stop(struct mei_device *dev)
 {
 	int ret;
-	u16 wd_timeout = dev->wd_timeout;
 
-	cancel_delayed_work(&dev->timer_work);
-	if (dev->wd_cl.state != MEI_FILE_CONNECTED || !dev->wd_timeout)
+	if (dev->wd_cl.state != MEI_FILE_CONNECTED ||
+	    dev->wd_state != MEI_WD_RUNNING)
 		return 0;
 
-	dev->wd_timeout = 0;
 	memcpy(dev->wd_data, mei_stop_wd_params, MEI_WD_STOP_MSG_SIZE);
-	dev->stop = true;
+
+	dev->wd_state = MEI_WD_STOPPING;
 
 	ret = mei_flow_ctrl_creds(dev, &dev->wd_cl);
 	if (ret < 0)
···
 	} else {
 		dev->wd_pending = true;
 	}
-	dev->wd_stopped = false;
+
 	mutex_unlock(&dev->device_lock);
 
 	ret = wait_event_interruptible_timeout(dev->wait_stop_wd,
-					dev->wd_stopped, 10 * HZ);
+					dev->wd_state == MEI_WD_IDLE,
+					msecs_to_jiffies(MEI_WD_STOP_TIMEOUT));
 	mutex_lock(&dev->device_lock);
-	if (dev->wd_stopped) {
+	if (dev->wd_state == MEI_WD_IDLE) {
 		dev_dbg(&dev->pdev->dev, "wd: stop completed ret=%d.\n", ret);
 		ret = 0;
 	} else {
···
 		dev_warn(&dev->pdev->dev,
 			"wd: stop failed to complete ret=%d.\n", ret);
 	}
-
-	if (preserve)
-		dev->wd_timeout = wd_timeout;
 
 out:
 	return ret;
···
 		return -ENODEV;
 
 	mutex_lock(&dev->device_lock);
-	mei_wd_stop(dev, false);
+	mei_wd_stop(dev);
 	mutex_unlock(&dev->device_lock);
 
 	return 0;
···
 		ret = -ENODEV;
 		goto end;
 	}
+
+	dev->wd_state = MEI_WD_RUNNING;
 
 	/* Check if we can send the ping to HW*/
 	if (dev->mei_host_buffer_is_empty &&