usb: dwc3: gadget: fix isoc END TRANSFER Condition

There were still some corner cases where isoc transfer was not able to
restart, specially when missed isoc does not happen , and in fact gadget does
not queue any new request during giveback.

Cleanup function calls giveback first, which provides a way to queue
another request to gadget. But gadget did not had any data. So , it did
not call ep_queue. To twist it further, gadget did not queue till
cleanup for last queued TRB is called. If we ever reach this scenario,
we must call END TRANSFER, so that we receive a new  xfernotready with
information about current microframe number.

Also insure that there is no request submitted to core when issuing END
TRANSFER.

Cc: <stable@vger.kernel.org> # v3.8
Signed-off-by: Pratyush Anand <pratyush.anand@st.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index c4ffb35..e60e72c 100644 (file)
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1089,7 +1089,10 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
                 * notion of current microframe.
                 */
                if (usb_endpoint_xfer_isoc(dep->endpoint.desc)) {
-                       dwc3_stop_active_transfer(dwc, dep->number);
+                       if (list_empty(&dep->req_queued)) {
+                               dwc3_stop_active_transfer(dwc, dep->number);
+                               dep->flags = DWC3_EP_ENABLED;
+                       }
                        return 0;
                }
 
@@ -1727,10 +1730,20 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep,
                        break;
        } while (1);
 
-       if (list_empty(&dep->req_queued) &&
-                       (dep->flags & DWC3_EP_MISSED_ISOC)) {
-               dwc3_stop_active_transfer(dwc, dep->number);
-               dep->flags &= ~DWC3_EP_MISSED_ISOC;
+       if (usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
+                       list_empty(&dep->req_queued)) {
+               if (list_empty(&dep->request_list)) {
+                       /*
+                        * If there is no entry in request list then do
+                        * not issue END TRANSFER now. Just set PENDING
+                        * flag, so that END TRANSFER is issued when an
+                        * entry is added into request list.
+                        */
+                       dep->flags = DWC3_EP_PENDING_REQUEST;
+               } else {
+                       dwc3_stop_active_transfer(dwc, dep->number);
+                       dep->flags = DWC3_EP_ENABLED;
+               }
                return 1;
        }