usb: dwc3: gadget: Delay starting transfer

If the END_TRANSFER command hasn't completed yet, then don't send the
START_TRANSFER command. The controller may not be able to start if
that's the case. Some controller revisions depend on this. See
commit 76a638f8ac0d ("usb: dwc3: gadget: wait for End Transfer to
complete"). Let's only send START_TRANSFER command after the
END_TRANSFER command had completed.

Fixes: 3aec99154db3 ("usb: dwc3: gadget: remove DWC3_EP_END_TRANSFER_PENDING")
Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index da0af11..77c4a9a 100644 (file)
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -690,6 +690,7 @@ struct dwc3_ep {
 #define DWC3_EP_TRANSFER_STARTED BIT(3)
 #define DWC3_EP_END_TRANSFER_PENDING BIT(4)
 #define DWC3_EP_PENDING_REQUEST        BIT(5)
+#define DWC3_EP_DELAY_START    BIT(6)
 
        /* This last one is specific to EP0 */
 #define DWC3_EP0_DIR_IN                BIT(31)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index cf163dc..696fbeb 100644 (file)
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1450,6 +1450,12 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
        list_add_tail(&req->list, &dep->pending_list);
        req->status = DWC3_REQUEST_STATUS_QUEUED;
 
+       /* Start the transfer only after the END_TRANSFER is completed */
+       if (dep->flags & DWC3_EP_END_TRANSFER_PENDING) {
+               dep->flags |= DWC3_EP_DELAY_START;
+               return 0;
+       }
+
        /*
         * NOTICE: Isochronous endpoints should NEVER be prestarted. We must
         * wait for a XferNotReady event so we will know what's the current
@@ -2631,6 +2637,11 @@ static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
                        dep->flags &= ~DWC3_EP_END_TRANSFER_PENDING;
                        dep->flags &= ~DWC3_EP_TRANSFER_STARTED;
                        dwc3_gadget_ep_cleanup_cancelled_requests(dep);
+                       if ((dep->flags & DWC3_EP_DELAY_START) &&
+                           !usb_endpoint_xfer_isoc(dep->endpoint.desc))
+                               __dwc3_gadget_kick_transfer(dep);
+
+                       dep->flags &= ~DWC3_EP_DELAY_START;
                }
                break;
        case DWC3_DEPEVT_STREAMEVT: