usb: dwc3: ep0: don't change to configured state too early

before changing to configured state, we need
to wait until gadget driver has had a chance
to process the request.

In case of USB_GADGET_DELAYED_STATUS, that means
we need to defer usb_gadget_set_state() until
the upcoming usb_ep_queue().
Reported-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc3/ep0.c

@@ -148,6 +148,7 @@ static int __dwc3_gadget_ep0_queue(struct dwc3_ep *dep,
 
 		direction = !dwc->ep0_expect_in;
 		dwc->delayed_status = false;
+		usb_gadget_set_state(&dwc->gadget, USB_STATE_CONFIGURED);
 
 		if (dwc->ep0state == EP0_STATUS_PHASE)
 			__dwc3_ep0_do_control_status(dwc, dwc->eps[direction]);
@@ -533,6 +534,14 @@ static int dwc3_ep0_set_config(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
 		ret = dwc3_ep0_delegate_req(dwc, ctrl);
 		/* if the cfg matches and the cfg is non zero */
 		if (cfg && (!ret || (ret == USB_GADGET_DELAYED_STATUS))) {
+
+			/*
+			 * only change state if set_config has already
+			 * been processed. If gadget driver returns
+			 * USB_GADGET_DELAYED_STATUS, we will wait
+			 * to change the state on the next usb_ep_queue()
+			 */
+			if (ret == 0)
 				usb_gadget_set_state(&dwc->gadget,
 						USB_STATE_CONFIGURED);