mei: hbm: reorganize the power gating responses

Before adding support for D0i3 we need to reorganize the hbm pg handling
Move HBM PG response code to dedicated functions in order to unclutter
hbm command switch.
Add check for the right system state before message processing and
return -EPROTO in state mismatch case.
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/hbm.c

@@ -879,6 +879,68 @@ static int mei_hbm_fw_disconnect_req(struct mei_device *dev,
 	return 0;
 }
 
+/**
+ * mei_hbm_pg_enter_res - PG enter response received
+ *
+ * @dev: the device structure.
+ *
+ * Return: 0 on success, -EPROTO on state mismatch
+ */
+static int mei_hbm_pg_enter_res(struct mei_device *dev)
+{
+	if (mei_pg_state(dev) != MEI_PG_OFF ||
+	    dev->pg_event != MEI_PG_EVENT_WAIT) {
+		dev_err(dev->dev, "hbm: pg entry response: state mismatch [%s, %d]\n",
+			mei_pg_state_str(mei_pg_state(dev)), dev->pg_event);
+		return -EPROTO;
+	}
+
+	dev->pg_event = MEI_PG_EVENT_RECEIVED;
+	wake_up(&dev->wait_pg);
+
+	return 0;
+}
+
+/**
+ * mei_hbm_pg_exit_res - PG exit response received
+ *
+ * @dev: the device structure.
+ *
+ * Return: 0 on success, -EPROTO on state mismatch
+ */
+static int mei_hbm_pg_exit_res(struct mei_device *dev)
+{
+	if (mei_pg_state(dev) != MEI_PG_ON ||
+	    (dev->pg_event != MEI_PG_EVENT_WAIT &&
+	     dev->pg_event != MEI_PG_EVENT_IDLE)) {
+		dev_err(dev->dev, "hbm: pg exit response: state mismatch [%s, %d]\n",
+			mei_pg_state_str(mei_pg_state(dev)), dev->pg_event);
+		return -EPROTO;
+	}
+
+	switch (dev->pg_event) {
+	case MEI_PG_EVENT_WAIT:
+		dev->pg_event = MEI_PG_EVENT_RECEIVED;
+		wake_up(&dev->wait_pg);
+		break;
+	case MEI_PG_EVENT_IDLE:
+		/*
+		* If the driver is not waiting on this then
+		* this is HW initiated exit from PG.
+		* Start runtime pm resume sequence to exit from PG.
+		*/
+		dev->pg_event = MEI_PG_EVENT_RECEIVED;
+		pm_request_resume(dev->dev);
+		break;
+	default:
+		WARN(1, "hbm: pg exit response: unexpected pg event = %d\n",
+		     dev->pg_event);
+		return -EPROTO;
+	}
+
+	return 0;
+}
+
 /**
  * mei_hbm_config_features - check what hbm features and commands
  *        are supported by the fw
@@ -1027,24 +1089,17 @@ int mei_hbm_dispatch(struct mei_device *dev, struct mei_msg_hdr *hdr)
 		break;
 
 	case MEI_PG_ISOLATION_ENTRY_RES_CMD:
-		dev_dbg(dev->dev, "power gate isolation entry response received\n");
-		dev->pg_event = MEI_PG_EVENT_RECEIVED;
-		if (waitqueue_active(&dev->wait_pg))
-			wake_up(&dev->wait_pg);
+		dev_dbg(dev->dev, "hbm: power gate isolation entry response received\n");
+		ret = mei_hbm_pg_enter_res(dev);
+		if (ret)
+			return ret;
 		break;
 
 	case MEI_PG_ISOLATION_EXIT_REQ_CMD:
-		dev_dbg(dev->dev, "power gate isolation exit request received\n");
-		dev->pg_event = MEI_PG_EVENT_RECEIVED;
-		if (waitqueue_active(&dev->wait_pg))
-			wake_up(&dev->wait_pg);
-		else
-			/*
-			* If the driver is not waiting on this then
-			* this is HW initiated exit from PG.
-			* Start runtime pm resume sequence to exit from PG.
-			*/
-			pm_request_resume(dev->dev);
+		dev_dbg(dev->dev, "hbm: power gate isolation exit request received\n");
+		ret = mei_hbm_pg_exit_res(dev);
+		if (ret)
+			return ret;
 		break;
 
 	case HOST_CLIENT_PROPERTIES_RES_CMD: