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-rw-r--r--drivers/usb/dwc3/ep0.c35
1 files changed, 35 insertions, 0 deletions
diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index 24b447e40bc7..36482f45b3b1 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -733,6 +733,41 @@ static void dwc3_ep0_do_control_status(struct dwc3 *dwc,
static void dwc3_ep0_xfernotready(struct dwc3 *dwc,
const struct dwc3_event_depevt *event)
{
+ /*
+ * This part is very tricky: If we has just handled
+ * XferNotReady(Setup) and we're now expecting a
+ * XferComplete but, instead, we receive another
+ * XferNotReady(Setup), we should STALL and restart
+ * the state machine.
+ *
+ * In all other cases, we just continue waiting
+ * for the XferComplete event.
+ *
+ * We are a little bit unsafe here because we're
+ * not trying to ensure that last event was, indeed,
+ * XferNotReady(Setup).
+ *
+ * Still, we don't expect any condition where that
+ * should happen and, even if it does, it would be
+ * another error condition.
+ */
+ if (dwc->ep0_next_event == DWC3_EP0_COMPLETE) {
+ switch (event->status) {
+ case DEPEVT_STATUS_CONTROL_SETUP:
+ dev_vdbg(dwc->dev, "Unexpected XferNotReady(Setup)\n");
+ dwc3_ep0_stall_and_restart(dwc);
+ break;
+ case DEPEVT_STATUS_CONTROL_DATA:
+ /* FALLTHROUGH */
+ case DEPEVT_STATUS_CONTROL_STATUS:
+ /* FALLTHROUGH */
+ default:
+ dev_vdbg(dwc->dev, "waiting for XferComplete\n");
+ }
+
+ return;
+ }
+
switch (event->status) {
case DEPEVT_STATUS_CONTROL_SETUP:
dev_vdbg(dwc->dev, "Control Setup\n");