usb: dwc3: gadget: END_TRANSFER before CLEAR_STALL command

According the programming guide (for all DWC3 IPs), when the driver
handles ClearFeature(halt) request, it should issue CLEAR_STALL command
_after_ the END_TRANSFER command completes. The END_TRANSFER command may
take some time to complete. So, delay the ClearFeature(halt) request
control status stage and wait for END_TRANSFER command completion
interrupt. Only after END_TRANSFER command completes that the driver
may issue CLEAR_STALL command.

Cc: stable@vger.kernel.org
Fixes: cb11ea56 ("usb: dwc3: gadget: Properly handle ClearFeature(halt)")
Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

drivers/usb/dwc3/core.h

@@ -706,6 +706,7 @@ struct dwc3_ep {
 #define DWC3_EP_IGNORE_NEXT_NOSTREAM	BIT(8)
 #define DWC3_EP_FORCE_RESTART_STREAM	BIT(9)
 #define DWC3_EP_FIRST_STREAM_PRIMED	BIT(10)
+#define DWC3_EP_PENDING_CLEAR_STALL	BIT(11)
 
 	/* This last one is specific to EP0 */
 #define DWC3_EP0_DIR_IN		BIT(31)

drivers/usb/dwc3/ep0.c

@@ -524,6 +524,11 @@ static int dwc3_ep0_handle_endpoint(struct dwc3 *dwc,
 		ret = __dwc3_gadget_ep_set_halt(dep, set, true);
 		if (ret)
 			return -EINVAL;
+
+		/* ClearFeature(Halt) may need delayed status */
+		if (!set && (dep->flags & DWC3_EP_END_TRANSFER_PENDING))
+			return USB_GADGET_DELAYED_STATUS;
+
 		break;
 	default:
 		return -EINVAL;
@@ -1042,6 +1047,17 @@ static void dwc3_ep0_do_control_status(struct dwc3 *dwc,
 	__dwc3_ep0_do_control_status(dwc, dep);
 }
 
+void dwc3_ep0_send_delayed_status(struct dwc3 *dwc)
+{
+	unsigned int direction = !dwc->ep0_expect_in;
+
+	if (dwc->ep0state != EP0_STATUS_PHASE)
+		return;
+
+	dwc->delayed_status = false;
+	__dwc3_ep0_do_control_status(dwc, dwc->eps[direction]);
+}
+
 static void dwc3_ep0_end_control_data(struct dwc3 *dwc, struct dwc3_ep *dep)
 {
 	struct dwc3_gadget_ep_cmd_params params;

drivers/usb/dwc3/gadget.c

@@ -1827,6 +1827,18 @@ int __dwc3_gadget_ep_set_halt(struct dwc3_ep *dep, int value, int protocol)
 			return 0;
 		}
 
+		dwc3_stop_active_transfer(dep, true, true);
+
+		list_for_each_entry_safe(req, tmp, &dep->started_list, list)
+			dwc3_gadget_move_cancelled_request(req);
+
+		if (dep->flags & DWC3_EP_END_TRANSFER_PENDING) {
+			dep->flags |= DWC3_EP_PENDING_CLEAR_STALL;
+			return 0;
+		}
+
+		dwc3_gadget_ep_cleanup_cancelled_requests(dep);
+
 		ret = dwc3_send_clear_stall_ep_cmd(dep);
 		if (ret) {
 			dev_err(dwc->dev, "failed to clear STALL on %s\n",
@@ -1836,14 +1848,6 @@ int __dwc3_gadget_ep_set_halt(struct dwc3_ep *dep, int value, int protocol)
 
 		dep->flags &= ~(DWC3_EP_STALL | DWC3_EP_WEDGE);
 
-		dwc3_stop_active_transfer(dep, true, true);
-
-		list_for_each_entry_safe(req, tmp, &dep->started_list, list)
-			dwc3_gadget_move_cancelled_request(req);
-
-		if (!(dep->flags & DWC3_EP_END_TRANSFER_PENDING))
-			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);
@@ -3003,6 +3007,26 @@ 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_PENDING_CLEAR_STALL) {
+				struct dwc3 *dwc = dep->dwc;
+
+				dep->flags &= ~DWC3_EP_PENDING_CLEAR_STALL;
+				if (dwc3_send_clear_stall_ep_cmd(dep)) {
+					struct usb_ep *ep0 = &dwc->eps[0]->endpoint;
+
+					dev_err(dwc->dev, "failed to clear STALL on %s\n",
+						dep->name);
+					if (dwc->delayed_status)
+						__dwc3_gadget_ep0_set_halt(ep0, 1);
+					return;
+				}
+
+				dep->flags &= ~(DWC3_EP_STALL | DWC3_EP_WEDGE);
+				if (dwc->delayed_status)
+					dwc3_ep0_send_delayed_status(dwc);
+			}
+
 			if ((dep->flags & DWC3_EP_DELAY_START) &&
 			    !usb_endpoint_xfer_isoc(dep->endpoint.desc))
 				__dwc3_gadget_kick_transfer(dep);

drivers/usb/dwc3/gadget.h

@@ -113,6 +113,7 @@ int dwc3_gadget_ep0_set_halt(struct usb_ep *ep, int value);
 int dwc3_gadget_ep0_queue(struct usb_ep *ep, struct usb_request *request,
 		gfp_t gfp_flags);
 int __dwc3_gadget_ep_set_halt(struct dwc3_ep *dep, int value, int protocol);
+void dwc3_ep0_send_delayed_status(struct dwc3 *dwc);
 
 /**
  * dwc3_gadget_ep_get_transfer_index - Gets transfer index from HW