usb: dwc3: ep0: simplify dwc3_ep0_handle_feature()

By extracting smaller functions from
dwc3_ep0_handle_feature(), it becomes far easier to
understand what's going on. Cleanup only, no
functional changes.
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/ep0.c

@@ -371,33 +371,11 @@ static int dwc3_ep0_handle_status(struct dwc3 *dwc,
 	return __dwc3_gadget_ep0_queue(dep, &dwc->ep0_usb_req);
 }
 
-static int dwc3_ep0_handle_feature(struct dwc3 *dwc,
-		struct usb_ctrlrequest *ctrl, int set)
+static int dwc3_ep0_handle_u1(struct dwc3 *dwc, enum usb_device_state state,
+		int set)
 {
-	struct dwc3_ep		*dep;
-	u32			recip;
-	u32			wValue;
-	u32			wIndex;
 	u32 reg;
-	int			ret;
-	enum usb_device_state	state;
 
-	wValue = le16_to_cpu(ctrl->wValue);
-	wIndex = le16_to_cpu(ctrl->wIndex);
-	recip = ctrl->bRequestType & USB_RECIP_MASK;
-	state = dwc->gadget.state;
-
-	switch (recip) {
-	case USB_RECIP_DEVICE:
-
-		switch (wValue) {
-		case USB_DEVICE_REMOTE_WAKEUP:
-			break;
-		/*
-		 * 9.4.1 says only only for SS, in AddressState only for
-		 * default control pipe
-		 */
-		case USB_DEVICE_U1_ENABLE:
 	if (state != USB_STATE_CONFIGURED)
 		return -EINVAL;
 	if ((dwc->speed != DWC3_DSTS_SUPERSPEED) &&
@@ -410,9 +388,16 @@ static int dwc3_ep0_handle_feature(struct dwc3 *dwc,
 	else
 		reg &= ~DWC3_DCTL_INITU1ENA;
 	dwc3_writel(dwc->regs, DWC3_DCTL, reg);
-			break;
 
-		case USB_DEVICE_U2_ENABLE:
+	return 0;
+}
+
+static int dwc3_ep0_handle_u2(struct dwc3 *dwc, enum usb_device_state state,
+		int set)
+{
+	u32 reg;
+
+
 	if (state != USB_STATE_CONFIGURED)
 		return -EINVAL;
 	if ((dwc->speed != DWC3_DSTS_SUPERSPEED) &&
@@ -425,12 +410,13 @@ static int dwc3_ep0_handle_feature(struct dwc3 *dwc,
 	else
 		reg &= ~DWC3_DCTL_INITU2ENA;
 	dwc3_writel(dwc->regs, DWC3_DCTL, reg);
-			break;
 
-		case USB_DEVICE_LTM_ENABLE:
-			return -EINVAL;
+	return 0;
+}
 
-		case USB_DEVICE_TEST_MODE:
+static int dwc3_ep0_handle_test(struct dwc3 *dwc, enum usb_device_state state,
+		u32 wIndex, int set)
+{
 	if ((wIndex & 0xff) != 0)
 		return -EINVAL;
 	if (!set)
@@ -448,13 +434,60 @@ static int dwc3_ep0_handle_feature(struct dwc3 *dwc,
 	default:
 		return -EINVAL;
 	}
+
+	return 0;
+}
+
+static int dwc3_ep0_handle_device(struct dwc3 *dwc,
+		struct usb_ctrlrequest *ctrl, int set)
+{
+	enum usb_device_state	state;
+	u32			wValue;
+	u32			wIndex;
+	int			ret = 0;
+
+	wValue = le16_to_cpu(ctrl->wValue);
+	wIndex = le16_to_cpu(ctrl->wIndex);
+	state = dwc->gadget.state;
+
+	switch (wValue) {
+	case USB_DEVICE_REMOTE_WAKEUP:
+		break;
+	/*
+	 * 9.4.1 says only only for SS, in AddressState only for
+	 * default control pipe
+	 */
+	case USB_DEVICE_U1_ENABLE:
+		ret = dwc3_ep0_handle_u1(dwc, state, set);
+		break;
+	case USB_DEVICE_U2_ENABLE:
+		ret = dwc3_ep0_handle_u2(dwc, state, set);
+		break;
+	case USB_DEVICE_LTM_ENABLE:
+		ret = -EINVAL;
+		break;
+	case USB_DEVICE_TEST_MODE:
+		ret = dwc3_ep0_handle_test(dwc, state, wIndex, set);
 		break;
 	default:
-			return -EINVAL;
+		ret = -EINVAL;
 	}
-		break;
 
-	case USB_RECIP_INTERFACE:
+	return ret;
+}
+
+static int dwc3_ep0_handle_intf(struct dwc3 *dwc,
+		struct usb_ctrlrequest *ctrl, int set)
+{
+	enum usb_device_state	state;
+	u32			wValue;
+	u32			wIndex;
+	int			ret = 0;
+
+	wValue = le16_to_cpu(ctrl->wValue);
+	wIndex = le16_to_cpu(ctrl->wIndex);
+	state = dwc->gadget.state;
+
 	switch (wValue) {
 	case USB_INTRF_FUNC_SUSPEND:
 		if (wIndex & USB_INTRF_FUNC_SUSPEND_LP)
@@ -465,18 +498,34 @@ static int dwc3_ep0_handle_feature(struct dwc3 *dwc,
 			;
 		break;
 	default:
-			return -EINVAL;
+		ret = -EINVAL;
 	}
-		break;
 
-	case USB_RECIP_ENDPOINT:
+	return ret;
+}
+
+static int dwc3_ep0_handle_endpoint(struct dwc3 *dwc,
+		struct usb_ctrlrequest *ctrl, int set)
+{
+	struct dwc3_ep		*dep;
+	enum usb_device_state	state;
+	u32			wValue;
+	u32			wIndex;
+	int			ret;
+
+	wValue = le16_to_cpu(ctrl->wValue);
+	wIndex = le16_to_cpu(ctrl->wIndex);
+	state = dwc->gadget.state;
+
 	switch (wValue) {
 	case USB_ENDPOINT_HALT:
 		dep = dwc3_wIndex_to_dep(dwc, ctrl->wIndex);
 		if (!dep)
 			return -EINVAL;
+
 		if (set == 0 && (dep->flags & DWC3_EP_WEDGE))
 			break;
+
 		ret = __dwc3_gadget_ep_set_halt(dep, set, true);
 		if (ret)
 			return -EINVAL;
@@ -484,13 +533,35 @@ static int dwc3_ep0_handle_feature(struct dwc3 *dwc,
 	default:
 		return -EINVAL;
 	}
-		break;
 
+	return 0;
+}
+
+static int dwc3_ep0_handle_feature(struct dwc3 *dwc,
+		struct usb_ctrlrequest *ctrl, int set)
+{
+	u32			recip;
+	int			ret;
+	enum usb_device_state	state;
+
+	recip = ctrl->bRequestType & USB_RECIP_MASK;
+	state = dwc->gadget.state;
+
+	switch (recip) {
+	case USB_RECIP_DEVICE:
+		ret = dwc3_ep0_handle_device(dwc, ctrl, set);
+		break;
+	case USB_RECIP_INTERFACE:
+		ret = dwc3_ep0_handle_intf(dwc, ctrl, set);
+		break;
+	case USB_RECIP_ENDPOINT:
+		ret = dwc3_ep0_handle_endpoint(dwc, ctrl, set);
+		break;
 	default:
-		return -EINVAL;
+		ret = -EINVAL;
 	}
 
-	return 0;
+	return ret;
 }
 
 static int dwc3_ep0_set_address(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)