HID: uhid: forward raw output reports to user-space

Some drivers that use non-standard HID features require raw output reports
sent to the device. We now forward these requests directly to user-space
so the transport-level driver can correctly send it to the device or
handle it correspondingly.

There is no way to signal back whether the transmission was successful,
moreover, there might be lots of messages coming out from the driver
flushing the output-queue. However, there is currently no driver that
causes this so we are safe. If some drivers need to transmit lots of data
this way, we need a method to synchronize this and can implement another
UHID_OUTPUT_SYNC event.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 33 insertions, 1 deletions

diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c
index 4dd693e1c8b8..421c492dc824 100644
--- a/drivers/hid/uhid.c
+++ b/drivers/hid/uhid.c
@@ -149,7 +149,39 @@ static int uhid_hid_get_raw(struct hid_device *hid, unsigned char rnum,
 static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count,
 			       unsigned char report_type)
 {
-	return 0;
+	struct uhid_device *uhid = hid->driver_data;
+	__u8 rtype;
+	unsigned long flags;
+	struct uhid_event *ev;
+
+	switch (report_type) {
+	case HID_FEATURE_REPORT:
+		rtype = UHID_FEATURE_REPORT;
+		break;
+	case HID_OUTPUT_REPORT:
+		rtype = UHID_OUTPUT_REPORT;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (count < 1 || count > UHID_DATA_MAX)
+		return -EINVAL;
+
+	ev = kzalloc(sizeof(*ev), GFP_KERNEL);
+	if (!ev)
+		return -ENOMEM;
+
+	ev->type = UHID_OUTPUT;
+	ev->u.output.size = count;
+	ev->u.output.rtype = rtype;
+	memcpy(ev->u.output.data, buf, count);
+
+	spin_lock_irqsave(&uhid->qlock, flags);
+	uhid_queue(uhid, ev);
+	spin_unlock_irqrestore(&uhid->qlock, flags);
+
+	return count;
 }
 
 static struct hid_ll_driver uhid_hid_driver = {