Instead of waiting for !BUSY, we can kick bulk
endpoints more frequently and rely on the fact that
__dwc3_gadget_kick_transfer() will use Update
Transfer if BUSY flag is set.
Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
---
drivers/usb/dwc3/gadget.c | 47 +++++++++++++++--------------------------------
1 file changed, 15 insertions(+), 32 deletions(-)
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 809445ec6a87..f9f7fe2c1e14 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1080,18 +1080,6 @@ 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)
@@ -1100,28 +1088,24 @@ 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.
+ * If this is a bulk endpoint, then just issue Start Transfer or Update
+ * Transfer straight away. This will possibly avoid a few XferNotReady
+ * events and let us recycle a struct usb_request earlier.
*
- * This will save one IRQ (XFER_NOT_READY) and possibly make it a
- * little bit faster.
*/
if (!usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
- !usb_endpoint_xfer_int(dep->endpoint.desc) &&
- !(dep->flags & DWC3_EP_BUSY)) {
+ !usb_endpoint_xfer_int(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.
+ * 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) {
@@ -1147,9 +1131,9 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
}
/*
- * 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).
+ * 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) &&
@@ -1160,9 +1144,8 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
}
/*
- * 4. Stream Capable Bulk Endpoints. We need to start the transfer
- * right away, otherwise host will not know we have streams to be
- * handled.
+ * 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);
--
2.8.2
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