[char-misc-next] mei: allow multiple retries if the hw reset has failed

[Tomas Winkler]

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@xxxxxxxxx>
Signed-off-by: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>
---
 drivers/misc/mei/hbm.c   |  2 +-
 drivers/misc/mei/hw-me.c |  2 +-
 drivers/misc/mei/hw.h    |  4 ++--
 drivers/misc/mei/init.c  | 40 ++++++++++++++++++++++++++++++----------
 4 files changed, 34 insertions(+), 14 deletions(-)

diff --git a/drivers/misc/mei/hbm.c b/drivers/misc/mei/hbm.c
index 28cd74c..0aaf2c5 100644
--- a/drivers/misc/mei/hbm.c
+++ b/drivers/misc/mei/hbm.c
@@ -147,7 +147,7 @@ int mei_hbm_start_wait(struct mei_device *dev)
 	ret = wait_event_interruptible_timeout(dev->wait_recvd_msg,
 			dev->hbm_state == MEI_HBM_IDLE ||
 			dev->hbm_state >= MEI_HBM_STARTED,
-			mei_secs_to_jiffies(MEI_INTEROP_TIMEOUT));
+			mei_secs_to_jiffies(MEI_HBM_TIMEOUT));
 	mutex_lock(&dev->device_lock);
 
 	if (ret <= 0 && (dev->hbm_state <= MEI_HBM_START)) {
diff --git a/drivers/misc/mei/hw-me.c b/drivers/misc/mei/hw-me.c
index 6f656c0..54286f3 100644
--- a/drivers/misc/mei/hw-me.c
+++ b/drivers/misc/mei/hw-me.c
@@ -240,7 +240,7 @@ static int mei_me_hw_ready_wait(struct mei_device *dev)
 	mutex_unlock(&dev->device_lock);
 	err = wait_event_interruptible_timeout(dev->wait_hw_ready,
 			dev->recvd_hw_ready,
-			mei_secs_to_jiffies(MEI_INTEROP_TIMEOUT));
+			mei_secs_to_jiffies(MEI_HW_READY_TIMEOUT));
 	mutex_lock(&dev->device_lock);
 	if (!err && !dev->recvd_hw_ready) {
 		if (!err)
diff --git a/drivers/misc/mei/hw.h b/drivers/misc/mei/hw.h
index dd44e33..e06779d 100644
--- a/drivers/misc/mei/hw.h
+++ b/drivers/misc/mei/hw.h
@@ -22,7 +22,7 @@
 /*
  * Timeouts in Seconds
  */
-#define MEI_INTEROP_TIMEOUT         7  /* Timeout on ready message */
+#define MEI_HW_READY_TIMEOUT        2  /* Timeout on ready message */
 #define MEI_CONNECT_TIMEOUT         3  /* HPS: at least 2 seconds */
 
 #define MEI_CL_CONNECT_TIMEOUT     15  /* HPS: Client Connect Timeout */
@@ -31,13 +31,13 @@
 #define MEI_IAMTHIF_STALL_TIMER    12  /* HPS */
 #define MEI_IAMTHIF_READ_TIMER     10  /* HPS */
 
+#define MEI_HBM_TIMEOUT            1   /* 1 second */
 
 /*
  * MEI Version
  */
 #define HBM_MINOR_VERSION                   0
 #define HBM_MAJOR_VERSION                   1
-#define HBM_TIMEOUT                         1	/* 1 second */
 
 /* Host bus message command opcode */
 #define MEI_HBM_CMD_OP_MSK                  0x7f
diff --git a/drivers/misc/mei/init.c b/drivers/misc/mei/init.c
index cdd31c2..95a7180 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)
-- 
1.8.4.2

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