USB: gadget: f_mtp: Zero length packet fixes
Send zero length packets at end of transfers that are a multiple of the
bulk max packet size as required by MTP.
Signed-off-by: Mike Lockwood <lockwood@android.com>
diff --git a/drivers/usb/gadget/f_mtp.c b/drivers/usb/gadget/f_mtp.c
index 03ea4a7..64fe3b3 100644
--- a/drivers/usb/gadget/f_mtp.c
+++ b/drivers/usb/gadget/f_mtp.c
@@ -540,6 +540,7 @@
struct usb_composite_dev *cdev = dev->cdev;
struct usb_request *req = 0;
int r = count, xfer;
+ int sendZLP = 0;
int ret;
DBG(cdev, "mtp_write(%d)\n", count);
@@ -558,8 +559,18 @@
dev->state = STATE_BUSY;
spin_unlock_irq(&dev->lock);
- /* condition check at bottom to allow zero length packet write */
- do {
+ /* we need to send a zero length packet to signal the end of transfer
+ * if the transfer size is aligned to a packet boundary.
+ */
+ if ((count & (dev->ep_in->maxpacket - 1)) == 0) {
+ sendZLP = 1;
+ }
+
+ while (count > 0 || sendZLP) {
+ /* so we exit after sending ZLP */
+ if (count == 0)
+ sendZLP = 0;
+
if (dev->state != STATE_BUSY) {
DBG(cdev, "mtp_write dev->error\n");
r = -EIO;
@@ -598,7 +609,7 @@
/* zero this so we don't try to free it on error exit */
req = 0;
- } while (count > 0);
+ }
if (req)
req_put(dev, &dev->tx_idle, req);
@@ -635,11 +646,9 @@
DBG(cdev, "send_file_work(%lld %lld)\n", offset, count);
/* we need to send a zero length packet to signal the end of transfer
- * if the length is > 4 gig and the last packet is aligned to a
- * packet boundary.
+ * if the transfer size is aligned to a packet boundary.
*/
- if (dev->xfer_file_length >= 0xFFFFFFFF
- && (dev->xfer_file_length & (dev->ep_in->maxpacket - 1)) == 0) {
+ if ((dev->xfer_file_length & (dev->ep_in->maxpacket - 1)) == 0) {
sendZLP = 1;
}