mei: allow multiple retries if the hw reset has failed

In some rare case mei hw reset may take long time to settle.
Instead of blocking resume flow we span another driver reset flow in
separate work context

This allows as to shorten hw reset timeout to something more acceptable
by DPM_WATCHDOG_TIMEOUT

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 30 insertions, 10 deletions

diff --git a/drivers/misc/mei/init.c b/drivers/misc/mei/init.c
index cdd31c2a2a2b..95a7180c75ea 100644
--- a/drivers/misc/mei/init.c
+++ b/drivers/misc/mei/init.c
@@ -126,7 +126,6 @@ int mei_reset(struct mei_device *dev)
 
 	if (ret) {
 		dev_err(&dev->pdev->dev, "hw_reset failed ret = %d\n", ret);
-		dev->dev_state = MEI_DEV_DISABLED;
 		return ret;
 	}
 
@@ -139,7 +138,6 @@ int mei_reset(struct mei_device *dev)
 	ret = mei_hw_start(dev);
 	if (ret) {
 		dev_err(&dev->pdev->dev, "hw_start failed ret = %d\n", ret);
-		dev->dev_state = MEI_DEV_DISABLED;
 		return ret;
 	}
 
@@ -149,7 +147,7 @@ int mei_reset(struct mei_device *dev)
 	ret = mei_hbm_start_req(dev);
 	if (ret) {
 		dev_err(&dev->pdev->dev, "hbm_start failed ret = %d\n", ret);
-		dev->dev_state = MEI_DEV_DISABLED;
+		dev->dev_state = MEI_DEV_RESETTING;
 		return ret;
 	}
 
@@ -166,6 +164,7 @@ EXPORT_SYMBOL_GPL(mei_reset);
  */
 int mei_start(struct mei_device *dev)
 {
+	int ret;
 	mutex_lock(&dev->device_lock);
 
 	/* acknowledge interrupt and stop interrupts */
@@ -175,10 +174,18 @@ int mei_start(struct mei_device *dev)
 
 	dev_dbg(&dev->pdev->dev, "reset in start the mei device.\n");
 
-	dev->dev_state = MEI_DEV_INITIALIZING;
 	dev->reset_count = 0;
-	mei_reset(dev);
+	do {
+		dev->dev_state = MEI_DEV_INITIALIZING;
+		ret = mei_reset(dev);
+
+		if (ret == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
+			dev_err(&dev->pdev->dev, "reset failed ret = %d", ret);
+			goto err;
+		}
+	} while (ret);
 
+	/* we cannot start the device w/o hbm start message completed */
 	if (dev->dev_state == MEI_DEV_DISABLED) {
 		dev_err(&dev->pdev->dev, "reset failed");
 		goto err;
@@ -238,27 +245,40 @@ int mei_restart(struct mei_device *dev)
 
 	mutex_unlock(&dev->device_lock);
 
-	if (err || dev->dev_state == MEI_DEV_DISABLED)
+	if (err == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
+		dev_err(&dev->pdev->dev, "device disabled = %d\n", err);
 		return -ENODEV;
+	}
+
+	/* try to start again */
+	if (err)
+		schedule_work(&dev->reset_work);
+
 
 	return 0;
 }
 EXPORT_SYMBOL_GPL(mei_restart);
 
-
 static void mei_reset_work(struct work_struct *work)
 {
 	struct mei_device *dev =
 		container_of(work, struct mei_device,  reset_work);
+	int ret;
 
 	mutex_lock(&dev->device_lock);
 
-	mei_reset(dev);
+	ret = mei_reset(dev);
 
 	mutex_unlock(&dev->device_lock);
 
-	if (dev->dev_state == MEI_DEV_DISABLED)
-		dev_err(&dev->pdev->dev, "reset failed");
+	if (dev->dev_state == MEI_DEV_DISABLED) {
+		dev_err(&dev->pdev->dev, "device disabled = %d\n", ret);
+		return;
+	}
+
+	/* retry reset in case of failure */
+	if (ret)
+		schedule_work(&dev->reset_work);
 }
 
 void mei_stop(struct mei_device *dev)