usb: dwc3: gadget: simplify __dwc3_gadget_ep_queue()

Many of the comments in that function are really
outdated and don't match what the driver is
doing. Moreover, recent patches combined programming
model for all non-control endpoints, this gives us
an opportunity to get rid of our special cases in
__dwc3_gadget_ep_queue().

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index a310266..3cf4c90 100644 (file)
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1063,18 +1063,6 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
 
        trace_dwc3_ep_queue(req);
 
-       /*
-        * We only add to our list of requests now and
-        * start consuming the list once we get XferNotReady
-        * IRQ.
-        *
-        * That way, we avoid doing anything that we don't need
-        * to do now and defer it until the point we receive a
-        * particular token from the Host side.
-        *
-        * This will also avoid Host cancelling URBs due to too
-        * many NAKs.
-        */
        ret = usb_gadget_map_request(&dwc->gadget, &req->request,
                        dep->direction);
        if (ret)
@@ -1082,73 +1070,16 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
 
        list_add_tail(&req->list, &dep->pending_list);
 
-       /*
-        * If there are no pending requests and the endpoint isn't already
-        * busy, we will just start the request straight away.
-        *
-        * This will save one IRQ (XFER_NOT_READY) and possibly make it a
-        * little bit faster.
-        */
-       if (!usb_endpoint_xfer_isoc(dep->endpoint.desc)) {
-               ret = __dwc3_gadget_kick_transfer(dep, 0);
-               goto out;
-       }
-
-       /*
-        * There are a few special cases:
-        *
-        * 1. XferNotReady with empty list of requests. We need to kick the
-        *    transfer here in that situation, otherwise we will be NAKing
-        *    forever. If we get XferNotReady before gadget driver has a
-        *    chance to queue a request, we will ACK the IRQ but won't be
-        *    able to receive the data until the next request is queued.
-        *    The following code is handling exactly that.
-        *
-        */
-       if (dep->flags & DWC3_EP_PENDING_REQUEST) {
-               /*
-                * If xfernotready is already elapsed and it is a case
-                * of isoc transfer, then issue END TRANSFER, so that
-                * you can receive xfernotready again and can have
-                * notion of current microframe.
-                */
-               if (usb_endpoint_xfer_isoc(dep->endpoint.desc)) {
-                       if (list_empty(&dep->started_list)) {
-                               dwc3_stop_active_transfer(dwc, dep->number, true);
-                               dep->flags = DWC3_EP_ENABLED;
-                       }
-                       return 0;
-               }
-
-               ret = __dwc3_gadget_kick_transfer(dep, 0);
-               if (!ret)
-                       dep->flags &= ~DWC3_EP_PENDING_REQUEST;
-
-               goto out;
-       }
-
-       /*
-        * 2. XferInProgress on Isoc EP with an active transfer. We need to
-        *    kick the transfer here after queuing a request, otherwise the
-        *    core may not see the modified TRB(s).
-        */
        if (usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
-                       (dep->flags & DWC3_EP_BUSY) &&
-                       !(dep->flags & DWC3_EP_MISSED_ISOC)) {
-               WARN_ON_ONCE(!dep->resource_index);
-               ret = __dwc3_gadget_kick_transfer(dep, dep->resource_index);
-               goto out;
+                       dep->flags & DWC3_EP_PENDING_REQUEST) {
+               if (list_empty(&dep->started_list)) {
+                       dwc3_stop_active_transfer(dwc, dep->number, true);
+                       dep->flags = DWC3_EP_ENABLED;
+               }
+               return 0;
        }
 
-       /*
-        * 4. Stream Capable Bulk Endpoints. We need to start the transfer
-        * right away, otherwise host will not know we have streams to be
-        * handled.
-        */
-       if (dep->stream_capable)
-               ret = __dwc3_gadget_kick_transfer(dep, 0);
-
-out:
+       ret = __dwc3_gadget_kick_transfer(dep, 0);
        if (ret && ret != -EBUSY)
                dwc3_trace(trace_dwc3_gadget,
                                "%s: failed to kick transfers",