mei: enqueue consecutive reads

The FW supports only one pending read per host client, in order to support issuing of consecutive reads the driver queues read requests internally and send them to the firmware after pending one has completed. Signed-off-by: Alexander Usyskin <[email protected]> Signed-off-by: Tomas Winkler <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
chewitt · Aug 30, 2016 · ff1586a · ff1586a
1 parent 3030dc0
commit ff1586a
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Showing 2 changed files with 22 additions and 20 deletions.
diff --git a/drivers/misc/mei/interrupt.c b/drivers/misc/mei/interrupt.c
@@ -209,6 +209,9 @@ static int mei_cl_irq_read(struct mei_cl *cl, struct mei_cl_cb *cb,
 	int slots;
 	int ret;
 
+	if (!list_empty(&cl->rd_pending))
+		return 0;
+
 	msg_slots = mei_data2slots(sizeof(struct hbm_flow_control));
 	slots = mei_hbuf_empty_slots(dev);
 

diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
@@ -139,9 +139,8 @@ static ssize_t mei_read(struct file *file, char __user *ubuf,
 	struct mei_cl *cl = file->private_data;
 	struct mei_device *dev;
 	struct mei_cl_cb *cb = NULL;
+	bool nonblock = !!(file->f_flags & O_NONBLOCK);
 	int rets;
-	int err;
-
 
 	if (WARN_ON(!cl || !cl->dev))
 		return -ENODEV;
@@ -177,25 +176,29 @@ static ssize_t mei_read(struct file *file, char __user *ubuf,
 	if (*offset > 0)
 		*offset = 0;
 
-	err = mei_cl_read_start(cl, length, file);
-	if (err && err != -EBUSY) {
-		cl_dbg(dev, cl, "mei start read failure status = %d\n", err);
-		rets = err;
+	rets = mei_cl_read_start(cl, length, file);
+	if (rets && rets != -EBUSY) {
+		cl_dbg(dev, cl, "mei start read failure status = %d\n", rets);
 		goto out;
 	}
 
-	/* synchronized under device mutex */
-	if (!waitqueue_active(&cl->rx_wait)) {
-		if (file->f_flags & O_NONBLOCK) {
-			rets = -EAGAIN;
-			goto out;
-		}
+	if (nonblock) {
+		rets = -EAGAIN;
+		goto out;
+	}
+
+	if (rets == -EBUSY &&
+	    !mei_cl_enqueue_ctrl_wr_cb(cl, length, MEI_FOP_READ, file)) {
+		rets = -ENOMEM;
+		goto out;
+	}
 
+	do {
 		mutex_unlock(&dev->device_lock);
 
 		if (wait_event_interruptible(cl->rx_wait,
-				(!list_empty(&cl->rd_completed)) ||
-				(!mei_cl_is_connected(cl)))) {
+					     (!list_empty(&cl->rd_completed)) ||
+					     (!mei_cl_is_connected(cl)))) {
 
 			if (signal_pending(current))
 				return -EINTR;
@@ -207,13 +210,9 @@ static ssize_t mei_read(struct file *file, char __user *ubuf,
 			rets = -ENODEV;
 			goto out;
 		}
-	}
 
-	cb = mei_cl_read_cb(cl, file);
-	if (!cb) {
-		rets = 0;
-		goto out;
-	}
+		cb = mei_cl_read_cb(cl, file);
+	} while (!cb);
 
 copy_buffer:
 	/* now copy the data to user space */