usb: dwc3: ep0: implement Set SEL support

This patch implements Set SEL Standard Request
support for dwc3 driver. It needs to issue a command
to the controller passing the timing we received on
the data phase of the Set SEL request.
Signed-off-by: NFelipe Balbi <balbi@ti.com>

drivers/usb/dwc3/core.h

@@ -575,6 +575,10 @@ struct dwc3_request {
  * @setup_packet_pending: true when there's a Setup Packet in FIFO. Workaround
  * @needs_fifo_resize: not all users might want fifo resizing, flag it
  * @resize_fifos: tells us it's ok to reconfigure our TxFIFO sizes.
+ * @u2sel: parameter from Set SEL request.
+ * @u2pel: parameter from Set SEL request.
+ * @u1sel: parameter from Set SEL request.
+ * @u1pel: parameter from Set SEL request.
  * @ep0_next_event: hold the next expected event
  * @ep0state: state of endpoint zero
  * @link_state: link state
@@ -641,7 +645,13 @@ struct dwc3 {
 	enum dwc3_link_state	link_state;
 	enum dwc3_device_state	dev_state;
 
+	u16			u2sel;
+	u16			u2pel;
+	u8			u1sel;
+	u8			u1pel;
+
 	u8			speed;
+
 	void			*mem;
 
 	struct dwc3_hwparams	hwparams;

drivers/usb/dwc3/ep0.c

@@ -490,6 +490,85 @@ static int dwc3_ep0_set_config(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
 	return ret;
 }
 
+static void dwc3_ep0_set_sel_cmpl(struct usb_ep *ep, struct usb_request *req)
+{
+	struct dwc3_ep	*dep = to_dwc3_ep(ep);
+	struct dwc3	*dwc = dep->dwc;
+
+	u32		param = 0;
+	u32		reg;
+
+	struct timing {
+		u8	u1sel;
+		u8	u1pel;
+		u16	u2sel;
+		u16	u2pel;
+	} __packed timing;
+
+	int		ret;
+
+	memcpy(&timing, req->buf, sizeof(timing));
+
+	dwc->u1sel = timing.u1sel;
+	dwc->u1pel = timing.u1pel;
+	dwc->u2sel = timing.u2sel;
+	dwc->u2pel = timing.u2pel;
+
+	reg = dwc3_readl(dwc->regs, DWC3_DCTL);
+	if (reg & DWC3_DCTL_INITU2ENA)
+		param = dwc->u2pel;
+	if (reg & DWC3_DCTL_INITU1ENA)
+		param = dwc->u1pel;
+
+	/*
+	 * According to Synopsys Databook, if parameter is
+	 * greater than 125, a value of zero should be
+	 * programmed in the register.
+	 */
+	if (param > 125)
+		param = 0;
+
+	/* now that we have the time, issue DGCMD Set Sel */
+	ret = dwc3_send_gadget_generic_command(dwc,
+			DWC3_DGCMD_SET_PERIODIC_PAR, param);
+	WARN_ON(ret < 0);
+}
+
+static int dwc3_ep0_set_sel(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
+{
+	struct dwc3_ep	*dep;
+	u16		wLength;
+	u16		wValue;
+
+	if (dwc->dev_state == DWC3_DEFAULT_STATE)
+		return -EINVAL;
+
+	wValue = le16_to_cpu(ctrl->wValue);
+	wLength = le16_to_cpu(ctrl->wLength);
+
+	if (wLength != 6) {
+		dev_err(dwc->dev, "Set SEL should be 6 bytes, got %d\n",
+				wLength);
+		return -EINVAL;
+	}
+
+	/*
+	 * To handle Set SEL we need to receive 6 bytes from Host. So let's
+	 * queue a usb_request for 6 bytes.
+	 *
+	 * Remember, though, this controller can't handle non-wMaxPacketSize
+	 * aligned transfers on the OUT direction, so we queue a request for
+	 * wMaxPacketSize instead.
+	 */
+	dep = dwc->eps[0];
+	dwc->ep0_usb_req.dep = dep;
+	dwc->ep0_usb_req.request.length = dep->endpoint.maxpacket;
+	dwc->ep0_usb_req.request.buf = dwc->setup_buf;
+	dwc->ep0_usb_req.request.complete = dwc3_ep0_set_sel_cmpl;
+
+	return __dwc3_gadget_ep0_queue(dep, &dwc->ep0_usb_req);
+}
+
 static int dwc3_ep0_std_request(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
 {
 	int ret;
@@ -515,6 +594,10 @@ static int dwc3_ep0_std_request(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
 		dev_vdbg(dwc->dev, "USB_REQ_SET_CONFIGURATION\n");
 		ret = dwc3_ep0_set_config(dwc, ctrl);
 		break;
+	case USB_REQ_SET_SEL:
+		dev_vdbg(dwc->dev, "USB_REQ_SET_SEL\n");
+		ret = dwc3_ep0_set_sel(dwc, ctrl);
+		break;
 	default:
 		dev_vdbg(dwc->dev, "Forwarding to gadget driver\n");
 		ret = dwc3_ep0_delegate_req(dwc, ctrl);