[PATCH v2] USB: gadget: s3c-hsotg: add isochronous transfers support

[Robert Baldyga]

Hello,

This is update for my proposal for isochronous transfers support in s3c-hsotg
driver. I've fixed issuses pointed by Bartlomiej Zolnierkiewicz. For more
information, please check the change log at the end of the mail.

This patch adds isochronous transfer support. It adds few modifications:
- Modify s3c_hsotg_write_fifo() function. It actually calculates transfer
  size, taking into account Multi Count value, which indicates number of
  transactions per microframe.
- Fix s3c_hsotg_start_req() function by setting number of packets to Multi
  Count field in DIEPTSIZ register for isochronous endpoints.
- Fix s3c_hsotg_set_ep_maxpacket() function. Field wMaxPacketSize of endpoint
  descriptor is now splitted into maximum packet size value and number of
  additional transaction per microframe.
- 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.
- Fix s3c_hsotg_ep_enable() function by supporting isochronous endpoint type.

Signed-off-by: Robert Baldyga <r.baldyga@xxxxxxxxxxx>
Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>

Changelog:

v2:
- moved bugfix affecting to the other features to separated patch
- changed conditions order in request length checking in s3c_hsotg_start_req
  function, as Bartlomiej Zolnierkiewicz suggested
- fixed typos

v1: https://lkml.org/lkml/2013/9/23/72
- initial proposal
---
 drivers/usb/gadget/s3c-hsotg.c |   72 +++++++++++++++++++++++++++++++---------
 1 file changed, 56 insertions(+), 16 deletions(-)

diff --git a/drivers/usb/gadget/s3c-hsotg.c b/drivers/usb/gadget/s3c-hsotg.c
index 2b9c446..ded9cb4 100644
--- a/drivers/usb/gadget/s3c-hsotg.c
+++ b/drivers/usb/gadget/s3c-hsotg.c
@@ -82,9 +82,12 @@ 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.
+ * @mc: Multi Count - number of transactions per microframe
+ * @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)
@@ -120,9 +123,12 @@ struct s3c_hsotg_ep {
 
 	unsigned char		dir_in;
 	unsigned char		index;
+	unsigned char		mc;
+	unsigned char		interval;
 
 	unsigned int		halted:1;
 	unsigned int		periodic:1;
+	unsigned int		isochronous:1;
 	unsigned int		sent_zlp:1;
 
 	char			name[10];
@@ -467,6 +473,7 @@ static int s3c_hsotg_write_fifo(struct s3c_hsotg *hsotg,
 	void *data;
 	int can_write;
 	int pkt_round;
+	int max_transfer;
 
 	to_write -= (buf_pos - hs_ep->last_load);
 
@@ -534,8 +541,10 @@ static int s3c_hsotg_write_fifo(struct s3c_hsotg *hsotg,
 		can_write *= 4;	/* fifo size is in 32bit quantities. */
 	}
 
-	dev_dbg(hsotg->dev, "%s: GNPTXSTS=%08x, can=%d, to=%d, mps %d\n",
-		 __func__, gnptxsts, can_write, to_write, hs_ep->ep.maxpacket);
+	max_transfer = hs_ep->ep.maxpacket * hs_ep->mc;
+
+	dev_dbg(hsotg->dev, "%s: GNPTXSTS=%08x, can=%d, to=%d, max_transfer %d\n",
+		 __func__, gnptxsts, can_write, to_write, max_transfer);
 
 	/*
 	 * limit to 512 bytes of data, it seems at least on the non-periodic
@@ -550,8 +559,8 @@ static int s3c_hsotg_write_fifo(struct s3c_hsotg *hsotg,
 	 * the transfer to return that it did not run out of fifo space
 	 * doing it.
 	 */
-	if (to_write > hs_ep->ep.maxpacket) {
-		to_write = hs_ep->ep.maxpacket;
+	if (to_write > max_transfer) {
+		to_write = max_transfer;
 
 		/* it's needed only when we do not use dedicated fifos */
 		if (!hsotg->dedicated_fifos)
@@ -564,7 +573,7 @@ static int s3c_hsotg_write_fifo(struct s3c_hsotg *hsotg,
 
 	if (to_write > can_write) {
 		to_write = can_write;
-		pkt_round = to_write % hs_ep->ep.maxpacket;
+		pkt_round = to_write % max_transfer;
 
 		/*
 		 * Round the write down to an
@@ -730,8 +739,16 @@ static void s3c_hsotg_start_req(struct s3c_hsotg *hsotg,
 	else
 		packets = 1;	/* send one packet if length is zero. */
 
+	if (hs_ep->isochronous && length > (hs_ep->mc * hs_ep->ep.maxpacket)) {
+		dev_err(hsotg->dev, "req length > maxpacket*mc\n");
+		return;
+	}
+
 	if (dir_in && index != 0)
-		epsize = DxEPTSIZ_MC(1);
+		if (hs_ep->isochronous)
+			epsize = DxEPTSIZ_MC(packets);
+		else
+			epsize = DxEPTSIZ_MC(1);
 	else
 		epsize = 0;
 
@@ -1718,6 +1735,7 @@ static void s3c_hsotg_set_ep_maxpacket(struct s3c_hsotg *hsotg,
 	struct s3c_hsotg_ep *hs_ep = &hsotg->eps[ep];
 	void __iomem *regs = hsotg->regs;
 	u32 mpsval;
+	u32 mcval;
 	u32 reg;
 
 	if (ep == 0) {
@@ -1725,15 +1743,19 @@ static void s3c_hsotg_set_ep_maxpacket(struct s3c_hsotg *hsotg,
 		mpsval = s3c_hsotg_ep0_mps(mps);
 		if (mpsval > 3)
 			goto bad_mps;
+		hs_ep->ep.maxpacket = mps;
+		hs_ep->mc = 1;
 	} else {
-		if (mps >= DxEPCTL_MPS_LIMIT+1)
+		mpsval = mps & 0x7ff;
+		mcval = ((mps >> 11) & 0x3) + 1;
+		hs_ep->mc = mcval;
+		if (mcval > 3) {
+			hs_ep->mc = 1;
 			goto bad_mps;
-
-		mpsval = mps;
+		}
+		hs_ep->ep.maxpacket = mpsval;
 	}
 
-	hs_ep->ep.maxpacket = mps;
-
 	/*
 	 * update both the in and out endpoint controldir_ registers, even
 	 * if one of the directions may not be in use.
@@ -1915,8 +1937,10 @@ 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);
@@ -1925,6 +1949,14 @@ 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),
@@ -1991,7 +2023,7 @@ 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",
@@ -2613,17 +2645,25 @@ static int s3c_hsotg_ep_enable(struct usb_ep *ep,
 	epctrl |= DxEPCTL_SNAK;
 
 	/* update the endpoint state */
-	hs_ep->ep.maxpacket = mps;
+	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->halted = 0;
+	hs_ep->interval = desc->bInterval;
+
+	if (hs_ep->interval > 1 && hs_ep->mc > 1)
+		dev_err(hsotg->dev, "MC > 1 when interval is not 1\n");
 
 	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;
-- 
1.7.9.5

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