mei: disconnect on connection request timeout

For the FW with  HBM version >= 2.0 we don't need to reset the whole
device in case of a particular client failing to connect, it is enough
to send disconnect a request to bring the device to the stable state.

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

drivers/misc/mei/client.c

@@ -836,44 +836,24 @@ int mei_cl_irq_disconnect(struct mei_cl *cl, struct mei_cl_cb *cb,
 	return ret;
 }
 
-
-
 /**
- * mei_cl_disconnect - disconnect host client from the me one
+ * __mei_cl_disconnect - disconnect host client from the me one
+ *     internal function runtime pm has to be already acquired
  *
  * @cl: host client
  *
- * Locking: called under "dev->device_lock" lock
- *
  * Return: 0 on success, <0 on failure.
  */
-int mei_cl_disconnect(struct mei_cl *cl)
+static int __mei_cl_disconnect(struct mei_cl *cl)
 {
 	struct mei_device *dev;
 	struct mei_cl_cb *cb;
 	int rets;
 
-	if (WARN_ON(!cl || !cl->dev))
-		return -ENODEV;
-
 	dev = cl->dev;
 
-	cl_dbg(dev, cl, "disconnecting");
-
-	if (!mei_cl_is_connected(cl))
-		return 0;
-
-	if (mei_cl_is_fixed_address(cl)) {
-		mei_cl_set_disconnected(cl);
-		return 0;
-	}
-
-	rets = pm_runtime_get(dev->dev);
-	if (rets < 0 && rets != -EINPROGRESS) {
-		pm_runtime_put_noidle(dev->dev);
-		cl_err(dev, cl, "rpm: get failed %d\n", rets);
-		return rets;
-	}
+	if (WARN_ON(!pm_runtime_active(dev->dev)))
+		return -EFAULT;
 
 	cl->state = MEI_FILE_DISCONNECTING;
 
@@ -910,11 +890,52 @@ out:
 	if (!rets)
 		cl_dbg(dev, cl, "successfully disconnected from FW client.\n");
 
+	mei_io_cb_free(cb);
+	return rets;
+}
+
+/**
+ * mei_cl_disconnect - disconnect host client from the me one
+ *
+ * @cl: host client
+ *
+ * Locking: called under "dev->device_lock" lock
+ *
+ * Return: 0 on success, <0 on failure.
+ */
+int mei_cl_disconnect(struct mei_cl *cl)
+{
+	struct mei_device *dev;
+	int rets;
+
+	if (WARN_ON(!cl || !cl->dev))
+		return -ENODEV;
+
+	dev = cl->dev;
+
+	cl_dbg(dev, cl, "disconnecting");
+
+	if (!mei_cl_is_connected(cl))
+		return 0;
+
+	if (mei_cl_is_fixed_address(cl)) {
+		mei_cl_set_disconnected(cl);
+		return 0;
+	}
+
+	rets = pm_runtime_get(dev->dev);
+	if (rets < 0 && rets != -EINPROGRESS) {
+		pm_runtime_put_noidle(dev->dev);
+		cl_err(dev, cl, "rpm: get failed %d\n", rets);
+		return rets;
+	}
+
+	rets = __mei_cl_disconnect(cl);
+
 	cl_dbg(dev, cl, "rpm: autosuspend\n");
 	pm_runtime_mark_last_busy(dev->dev);
 	pm_runtime_put_autosuspend(dev->dev);
 
-	mei_io_cb_free(cb);
 	return rets;
 }
 
@@ -1059,11 +1080,23 @@ int mei_cl_connect(struct mei_cl *cl, struct mei_me_client *me_cl,
 	mutex_unlock(&dev->device_lock);
 	wait_event_timeout(cl->wait,
 			(cl->state == MEI_FILE_CONNECTED ||
+			 cl->state == MEI_FILE_DISCONNECT_REQUIRED ||
 			 cl->state == MEI_FILE_DISCONNECT_REPLY),
 			mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT));
 	mutex_lock(&dev->device_lock);
 
 	if (!mei_cl_is_connected(cl)) {
+		if (cl->state == MEI_FILE_DISCONNECT_REQUIRED) {
+			mei_io_list_flush(&dev->ctrl_rd_list, cl);
+			mei_io_list_flush(&dev->ctrl_wr_list, cl);
+			 /* ignore disconnect return valuue;
+			  * in case of failure reset will be invoked
+			  */
+			__mei_cl_disconnect(cl);
+			rets = -EFAULT;
+			goto out;
+		}
+
 		/* timeout or something went really wrong */
 		if (!cl->status)
 			cl->status = -EFAULT;

drivers/misc/mei/debugfs.c

@@ -156,6 +156,8 @@ static ssize_t mei_dbgfs_read_devstate(struct file *fp, char __user *ubuf,
 				 dev->hbm_f_pg_supported);
 		pos += scnprintf(buf + pos, bufsz - pos, "\tDC: %01d\n",
 				 dev->hbm_f_dc_supported);
+		pos += scnprintf(buf + pos, bufsz - pos, "\tDOT: %01d\n",
+				 dev->hbm_f_dot_supported);
 	}
 
 	pos += scnprintf(buf + pos, bufsz - pos, "pg:  %s, %s\n",

drivers/misc/mei/hbm.c

@@ -774,6 +774,10 @@ static void mei_hbm_config_features(struct mei_device *dev)
 
 	if (dev->version.major_version >= HBM_MAJOR_VERSION_DC)
 		dev->hbm_f_dc_supported = 1;
+
+	/* disconnect on connect timeout instead of link reset */
+	if (dev->version.major_version >= HBM_MAJOR_VERSION_DOT)
+		dev->hbm_f_dot_supported = 1;
 }
 
 /**

drivers/misc/mei/hw.h

@@ -52,6 +52,12 @@
 #define HBM_MINOR_VERSION_DC               0
 #define HBM_MAJOR_VERSION_DC               2
 
+/*
+ * MEI version with disconnect on connection timeout support
+ */
+#define HBM_MINOR_VERSION_DOT              0
+#define HBM_MAJOR_VERSION_DOT              2
+
 /* Host bus message command opcode */
 #define MEI_HBM_CMD_OP_MSK                  0x7f
 /* Host bus message command RESPONSE */

drivers/misc/mei/interrupt.c

@@ -424,6 +424,24 @@ int mei_irq_write_handler(struct mei_device *dev, struct mei_cl_cb *cmpl_list)
 EXPORT_SYMBOL_GPL(mei_irq_write_handler);
 
 
+/**
+ * mei_connect_timeout  - connect/disconnect timeouts
+ *
+ * @cl: host client
+ */
+static void mei_connect_timeout(struct mei_cl *cl)
+{
+	struct mei_device *dev = cl->dev;
+
+	if (cl->state == MEI_FILE_CONNECTING) {
+		if (dev->hbm_f_dot_supported) {
+			cl->state = MEI_FILE_DISCONNECT_REQUIRED;
+			wake_up(&cl->wait);
+			return;
+		}
+	}
+	mei_reset(dev);
+}
 
 /**
  * mei_timer - timer function.
@@ -464,7 +482,7 @@ void mei_timer(struct work_struct *work)
 		if (cl->timer_count) {
 			if (--cl->timer_count == 0) {
 				dev_err(dev->dev, "timer: connect/disconnect timeout.\n");
-				mei_reset(dev);
+				mei_connect_timeout(cl);
 				goto out;
 			}
 		}

drivers/misc/mei/mei_dev.h

@@ -89,6 +89,7 @@ enum file_state {
 	MEI_FILE_CONNECTED,
 	MEI_FILE_DISCONNECTING,
 	MEI_FILE_DISCONNECT_REPLY,
+	MEI_FILE_DISCONNECT_REQUIRED,
 	MEI_FILE_DISCONNECTED,
 };
 
@@ -407,8 +408,9 @@ const char *mei_pg_state_str(enum mei_pg_state state);
  * @wr_msg      : the buffer for hbm control messages
  *
  * @version     : HBM protocol version in use
- * @hbm_f_pg_supported : hbm feature pgi protocol
- * @hbm_f_dc_supported : hbm feature dynamic clients
+ * @hbm_f_pg_supported  : hbm feature pgi protocol
+ * @hbm_f_dc_supported  : hbm feature dynamic clients
+ * @hbm_f_dot_supported : hbm feature disconnect on timeout
  *
  * @me_clients_rwsem: rw lock over me_clients list
  * @me_clients  : list of FW clients
@@ -503,6 +505,7 @@ struct mei_device {
 	struct hbm_version version;
 	unsigned int hbm_f_pg_supported:1;
 	unsigned int hbm_f_dc_supported:1;
+	unsigned int hbm_f_dot_supported:1;
 
 	struct rw_semaphore me_clients_rwsem;
 	struct list_head me_clients;