usb: gadget: s3c-hsotg: add isochronous transfers support

This patch adds isochronous transfer support. It adds few modifications:
- Modify s3c_hsotg_epint() function. Some interrupts are ignored for
  isochronous endpoints, (e.g. INTknTXFEmpMsk) becouse isochronous request is
  always transfered in single transaction, which ends with XferCompl interrupt.
- Add Odd/Even microframe toggle to allow data transfering in each microframe
  in s3c_hsotg_epint() function.
- Fix s3c_hsotg_ep_enable() function by supporting isochronous endpoint type.
Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/s3c-hsotg.c

@@ -83,9 +83,11 @@ struct s3c_hsotg_req;
  * @dir_in: Set to true if this endpoint is of the IN direction, which
  *	    means that it is sending data to the Host.
  * @index: The index for the endpoint registers.
+ * @interval - Interval for periodic endpoints
  * @name: The name array passed to the USB core.
  * @halted: Set if the endpoint has been halted.
  * @periodic: Set if this is a periodic ep, such as Interrupt
+ * @isochronous: Set if this is a isochronous ep
  * @sent_zlp: Set if we've sent a zero-length packet.
  * @total_data: The total number of data bytes done.
  * @fifo_size: The size of the FIFO (for periodic IN endpoints)
@@ -121,9 +123,11 @@ struct s3c_hsotg_ep {
 
 	unsigned char		dir_in;
 	unsigned char		index;
+	unsigned char		interval;
 
 	unsigned int		halted:1;
 	unsigned int		periodic:1;
+	unsigned int		isochronous:1;
 	unsigned int		sent_zlp:1;
 
 	char			name[10];
@@ -1886,8 +1890,10 @@ static void s3c_hsotg_epint(struct s3c_hsotg *hsotg, unsigned int idx,
 	u32 epctl_reg = dir_in ? DIEPCTL(idx) : DOEPCTL(idx);
 	u32 epsiz_reg = dir_in ? DIEPTSIZ(idx) : DOEPTSIZ(idx);
 	u32 ints;
+	u32 ctrl;
 
 	ints = readl(hsotg->regs + epint_reg);
+	ctrl = readl(hsotg->regs + epctl_reg);
 
 	/* Clear endpoint interrupts */
 	writel(ints, hsotg->regs + epint_reg);
@@ -1896,6 +1902,14 @@ static void s3c_hsotg_epint(struct s3c_hsotg *hsotg, unsigned int idx,
 		__func__, idx, dir_in ? "in" : "out", ints);
 
 	if (ints & DxEPINT_XferCompl) {
+		if (hs_ep->isochronous && hs_ep->interval == 1) {
+			if (ctrl & DxEPCTL_EOFrNum)
+				ctrl |= DxEPCTL_SetEvenFr;
+			else
+				ctrl |= DxEPCTL_SetOddFr;
+			writel(ctrl, hsotg->regs + epctl_reg);
+		}
+
 		dev_dbg(hsotg->dev,
 			"%s: XferCompl: DxEPCTL=0x%08x, DxEPTSIZ=%08x\n",
 			__func__, readl(hsotg->regs + epctl_reg),
@@ -1962,7 +1976,7 @@ static void s3c_hsotg_epint(struct s3c_hsotg *hsotg, unsigned int idx,
 	if (ints & DxEPINT_Back2BackSetup)
 		dev_dbg(hsotg->dev, "%s: B2BSetup/INEPNakEff\n", __func__);
 
-	if (dir_in) {
+	if (dir_in && !hs_ep->isochronous) {
 		/* not sure if this is important, but we'll clear it anyway */
 		if (ints & DIEPMSK_INTknTXFEmpMsk) {
 			dev_dbg(hsotg->dev, "%s: ep%d: INTknTXFEmpMsk\n",
@@ -2581,13 +2595,18 @@ static int s3c_hsotg_ep_enable(struct usb_ep *ep,
 	s3c_hsotg_set_ep_maxpacket(hsotg, hs_ep->index, mps);
 
 	/* default, set to non-periodic */
+	hs_ep->isochronous = 0;
 	hs_ep->periodic = 0;
+	hs_ep->interval = desc->bInterval;
 
 	switch (desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) {
 	case USB_ENDPOINT_XFER_ISOC:
-		dev_err(hsotg->dev, "no current ISOC support\n");
-		ret = -EINVAL;
-		goto out;
+		epctrl |= DxEPCTL_EPType_Iso;
+		epctrl |= DxEPCTL_SetEvenFr;
+		hs_ep->isochronous = 1;
+		if (dir_in)
+			hs_ep->periodic = 1;
+		break;
 
 	case USB_ENDPOINT_XFER_BULK:
 		epctrl |= DxEPCTL_EPType_Bulk;