usb: dwc3: ep0: drop XferNotReady(DATA) support

Due to the late Silicon limitation found, we are
now pre-starting DATA phase's TRBs. If, still, we
get XferNotReady(DATA) we will ignore it unless
we're getting it for the wrong direction.

In that case we must keep the error case handling
plus add a ENDTRANSFER command to forcefully end
the Data TRB we started previously, then continue
to SetStall and so on.
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc3/ep0.c

@@ -923,29 +923,6 @@ static void __dwc3_ep0_do_control_data(struct dwc3 *dwc,
 	WARN_ON(ret < 0);
 }
 
-static void dwc3_ep0_do_control_data(struct dwc3 *dwc,
-		const struct dwc3_event_depevt *event)
-{
-	struct dwc3_ep		*dep;
-	struct dwc3_request	*req;
-
-	dep = dwc->eps[0];
-
-	if (list_empty(&dep->request_list)) {
-		dev_vdbg(dwc->dev, "pending request for EP0 Data phase\n");
-		dep->flags |= DWC3_EP_PENDING_REQUEST;
-
-		if (event->endpoint_number)
-			dep->flags |= DWC3_EP0_DIR_IN;
-		return;
-	}
-
-	req = next_request(&dep->request_list);
-	dep = dwc->eps[event->endpoint_number];
-
-	__dwc3_ep0_do_control_data(dwc, dep, req);
-}
-
 static int dwc3_ep0_start_control_status(struct dwc3_ep *dep)
 {
 	struct dwc3		*dwc = dep->dwc;
@@ -977,6 +954,24 @@ static void dwc3_ep0_do_control_status(struct dwc3 *dwc,
 	__dwc3_ep0_do_control_status(dwc, dep);
 }
 
+static void dwc3_ep0_end_control_data(struct dwc3 *dwc, struct dwc3_ep *dep)
+{
+	struct dwc3_gadget_ep_cmd_params params;
+	u32			cmd;
+	int			ret;
+
+	if (!dep->resource_index)
+		return;
+
+	cmd = DWC3_DEPCMD_ENDTRANSFER;
+	cmd |= DWC3_DEPCMD_CMDIOC;
+	cmd |= DWC3_DEPCMD_PARAM(dep->resource_index);
+	memset(&params, 0, sizeof(params));
+	ret = dwc3_send_gadget_ep_cmd(dwc, dep->number, cmd, &params);
+	WARN_ON_ONCE(ret);
+	dep->resource_index = 0;
+}
+
 static void dwc3_ep0_xfernotready(struct dwc3 *dwc,
 		const struct dwc3_event_depevt *event)
 {
@@ -986,32 +981,24 @@ static void dwc3_ep0_xfernotready(struct dwc3 *dwc,
 	case DEPEVT_STATUS_CONTROL_DATA:
 		dev_vdbg(dwc->dev, "Control Data\n");
 
-		dwc->ep0state = EP0_DATA_PHASE;
-
-		if (dwc->ep0_next_event != DWC3_EP0_NRDY_DATA) {
-			dev_vdbg(dwc->dev, "Expected %d got %d\n",
-					dwc->ep0_next_event,
-					DWC3_EP0_NRDY_DATA);
-
-			dwc3_ep0_stall_and_restart(dwc);
-			return;
-		}
-
 		/*
-		 * One of the possible error cases is when Host _does_
-		 * request for Data Phase, but it does so on the wrong
-		 * direction.
+		 * We already have a DATA transfer in the controller's cache,
+		 * if we receive a XferNotReady(DATA) we will ignore it, unless
+		 * it's for the wrong direction.
 		 *
-		 * Here, we already know ep0_next_event is DATA (see above),
-		 * so we only need to check for direction.
+		 * In that case, we must issue END_TRANSFER command to the Data
+		 * Phase we already have started and issue SetStall on the
+		 * control endpoint.
 		 */
 		if (dwc->ep0_expect_in != event->endpoint_number) {
+			struct dwc3_ep	*dep = dwc->eps[dwc->ep0_expect_in];
+
 			dev_vdbg(dwc->dev, "Wrong direction for Data phase\n");
+			dwc3_ep0_end_control_data(dwc, dep);
 			dwc3_ep0_stall_and_restart(dwc);
 			return;
 		}
 
-		dwc3_ep0_do_control_data(dwc, event);
 		break;
 
 	case DEPEVT_STATUS_CONTROL_STATUS: