mei: add a handler that waits for notification on event

mei_cl_notify_get is to be called by a host client
to wait, receive, and ack the event notification.
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>

drivers/misc/mei/client.c

@@ -555,6 +555,7 @@ void mei_cl_init(struct mei_cl *cl, struct mei_device *dev)
 	init_waitqueue_head(&cl->wait);
 	init_waitqueue_head(&cl->rx_wait);
 	init_waitqueue_head(&cl->tx_wait);
+	init_waitqueue_head(&cl->ev_wait);
 	INIT_LIST_HEAD(&cl->rd_completed);
 	INIT_LIST_HEAD(&cl->rd_pending);
 	INIT_LIST_HEAD(&cl->link);
@@ -1349,6 +1350,51 @@ int mei_cl_notify_request(struct mei_cl *cl, struct file *file, u8 request)
 	return rets;
 }
 
+/**
+ * mei_cl_notify_get - get or wait for notification event
+ *
+ * @cl: host client
+ * @block: this request is blocking
+ * @notify_ev: true if notification event was received
+ *
+ * Locking: called under "dev->device_lock" lock
+ *
+ * Return: 0 on such and error otherwise.
+ */
+int mei_cl_notify_get(struct mei_cl *cl, bool block, bool *notify_ev)
+{
+	struct mei_device *dev;
+	int rets;
+
+	*notify_ev = false;
+
+	if (WARN_ON(!cl || !cl->dev))
+		return -ENODEV;
+
+	dev = cl->dev;
+
+	if (!mei_cl_is_connected(cl))
+		return -ENODEV;
+
+	if (cl->notify_ev)
+		goto out;
+
+	if (!block)
+		return -EAGAIN;
+
+	mutex_unlock(&dev->device_lock);
+	rets = wait_event_interruptible(cl->ev_wait, cl->notify_ev);
+	mutex_lock(&dev->device_lock);
+
+	if (rets < 0)
+		return rets;
+
+out:
+	*notify_ev = cl->notify_ev;
+	cl->notify_ev = false;
+	return 0;
+}
+
 /**
  * mei_cl_read_start - the start read client message function.
  *
@@ -1701,6 +1747,12 @@ void mei_cl_all_wakeup(struct mei_device *dev)
 			cl_dbg(dev, cl, "Waking up writing client!\n");
 			wake_up_interruptible(&cl->tx_wait);
 		}
+
+		/* synchronized under device mutex */
+		if (waitqueue_active(&cl->ev_wait)) {
+			cl_dbg(dev, cl, "Waking up waiting for event clients!\n");
+			wake_up_interruptible(&cl->ev_wait);
+		}
 	}
 }
 

drivers/misc/mei/client.h

@@ -224,6 +224,7 @@ enum mei_cb_file_ops mei_cl_notify_req2fop(u8 request);
 int mei_cl_notify_request(struct mei_cl *cl, struct file *file, u8 request);
 int mei_cl_irq_notify(struct mei_cl *cl, struct mei_cl_cb *cb,
 		      struct mei_cl_cb *cmpl_list);
+int mei_cl_notify_get(struct mei_cl *cl, bool block, bool *notify_ev);
 
 void mei_cl_all_disconnect(struct mei_device *dev);
 void mei_cl_all_wakeup(struct mei_device *dev);

drivers/misc/mei/hbm.c

@@ -514,8 +514,10 @@ static void mei_hbm_cl_notify(struct mei_device *dev,
 	struct mei_cl *cl;
 
 	cl = mei_hbm_cl_find_by_cmd(dev, cmd);
-	if (cl && cl->notify_en)
+	if (cl && cl->notify_en) {
 		cl->notify_ev = true;
+		wake_up_interruptible(&cl->ev_wait);
+	}
 }
 
 /**

drivers/misc/mei/mei_dev.h

@@ -235,6 +235,7 @@ struct mei_cl_cb {
  * @tx_wait: wait queue for tx completion
  * @rx_wait: wait queue for rx completion
  * @wait:  wait queue for management operation
+ * @ev_wait: notification wait queue
  * @status: connection status
  * @me_cl: fw client connected
  * @host_client_id: host id
@@ -256,6 +257,7 @@ struct mei_cl {
 	wait_queue_head_t tx_wait;
 	wait_queue_head_t rx_wait;
 	wait_queue_head_t wait;
+	wait_queue_head_t ev_wait;
 	int status;
 	struct mei_me_client *me_cl;
 	u8 host_client_id;