usb: dwc3: gadget: Continue to process pending requests

If there are still pending requests because no TRB was available,
prepare more when started requests are completed.

Introduce dwc3_gadget_ep_should_continue() to check for incomplete and
pending requests to resume updating new TRBs to the controller's TRB
cache.

Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index a055525..20b593e 100644 (file)
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2600,10 +2600,8 @@ static int dwc3_gadget_ep_cleanup_completed_request(struct dwc3_ep *dep,
 
        req->request.actual = req->request.length - req->remaining;
 
-       if (!dwc3_gadget_ep_request_completed(req)) {
-               __dwc3_gadget_kick_transfer(dep);
+       if (!dwc3_gadget_ep_request_completed(req))
                goto out;
-       }
 
        dwc3_gadget_giveback(dep, req, status);
 
@@ -2627,6 +2625,24 @@ static void dwc3_gadget_ep_cleanup_completed_requests(struct dwc3_ep *dep,
        }
 }
 
+static bool dwc3_gadget_ep_should_continue(struct dwc3_ep *dep)
+{
+       struct dwc3_request     *req;
+
+       if (!list_empty(&dep->pending_list))
+               return true;
+
+       /*
+        * We only need to check the first entry of the started list. We can
+        * assume the completed requests are removed from the started list.
+        */
+       req = next_request(&dep->started_list);
+       if (!req)
+               return false;
+
+       return !dwc3_gadget_ep_request_completed(req);
+}
+
 static void dwc3_gadget_endpoint_frame_from_event(struct dwc3_ep *dep,
                const struct dwc3_event_depevt *event)
 {
@@ -2656,6 +2672,8 @@ static void dwc3_gadget_endpoint_transfer_in_progress(struct dwc3_ep *dep,
 
        if (stop)
                dwc3_stop_active_transfer(dep, true, true);
+       else if (dwc3_gadget_ep_should_continue(dep))
+               __dwc3_gadget_kick_transfer(dep);
 
        /*
         * WORKAROUND: This is the 2nd half of U1/U2 -> U0 workaround.