commit d2ff51b372a6800fcf1394fc2ca9821d86b15335
author Stefan Brüns <stefan.bruens@rwth-aachen.de> Sun Jan 17 04:09:56 2016 +0100
committer Marek Vasut <marex@denx.de> Sat Jan 23 16:21:11 2016 +0100
tree d7524ea5df1b698bb0f548c00a88437c18780e73
parent b54e44705258c0443310ed12b8982707d7992fa8

usb: dwc2: Add SPLIT INTERRUPT transaction support

CSPLITs for INTERRUPT transactions have to be scheduled in each microframe
following the SSPLIT. INTERRUPT transfers are executed in the next even/
odd microframe depending on the HCCHAR_ODDFRM flag.

As there are no handshakes for INTERRUPT SSPLITs the SSPLIT may have
failed (transport error) without the error being detected by the host
driver. If the last CSPLIT is not received within 4 microframes after the
SSPLIT there was a transaction error and the complete transaction has
to be restarted.

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>

drivers/usb/host/dwc2.c

diff --git a/drivers/usb/host/dwc2.c b/drivers/usb/host/dwc2.c
index 413845c..291e4a5 100644
--- a/drivers/usb/host/dwc2.c
+++ b/drivers/usb/host/dwc2.c
@@ -776,7 +776,7 @@
 
 static int transfer_chunk(struct dwc2_hc_regs *hc_regs, void *aligned_buffer,
 			  int *pid, int in, void *buffer, int num_packets,
-			  int xfer_len, int *actual_len)
+			  int xfer_len, int *actual_len, int odd_frame)
 {
 	int ret = 0;
 	uint32_t sub;
@@ -804,8 +804,10 @@
 
 	/* Set host channel enable after all other setup is complete. */
 	clrsetbits_le32(&hc_regs->hcchar, DWC2_HCCHAR_MULTICNT_MASK |
-			DWC2_HCCHAR_CHEN | DWC2_HCCHAR_CHDIS,
+			DWC2_HCCHAR_CHEN | DWC2_HCCHAR_CHDIS |
+			DWC2_HCCHAR_ODDFRM,
 			(1 << DWC2_HCCHAR_MULTICNT_OFFSET) |
+			(odd_frame << DWC2_HCCHAR_ODDFRM_OFFSET) |
 			DWC2_HCCHAR_CHEN);
 
 	ret = wait_for_chhltd(hc_regs, &sub, pid);
@@ -831,6 +833,7 @@
 {
 	struct dwc2_core_regs *regs = priv->regs;
 	struct dwc2_hc_regs *hc_regs = &regs->hc_regs[DWC2_HC_CHANNEL];
+	struct dwc2_host_regs *host_regs = &regs->host_regs;
 	int devnum = usb_pipedevice(pipe);
 	int ep = usb_pipeendpoint(pipe);
 	int max = usb_maxpacket(dev, pipe);
@@ -843,6 +846,7 @@
 	uint32_t num_packets;
 	int stop_transfer = 0;
 	uint32_t max_xfer_len;
+	int ssplit_frame_num = 0;
 
 	debug("%s: msg: pipe %lx pid %d in %d len %d\n", __func__, pipe, *pid,
 	      in, len);
@@ -881,6 +885,7 @@
 	do {
 		int actual_len = 0;
 		uint32_t hcint;
+		int odd_frame = 0;
 		xfer_len = len - done;
 
 		if (xfer_len > max_xfer_len)
@@ -895,19 +900,32 @@
 		else if (do_split)
 			clrbits_le32(&hc_regs->hcsplt, DWC2_HCSPLT_COMPSPLT);
 
+		if (eptype == DWC2_HCCHAR_EPTYPE_INTR) {
+			int uframe_num = readl(&host_regs->hfnum);
+			if (!(uframe_num & 0x1))
+				odd_frame = 1;
+		}
+
 		ret = transfer_chunk(hc_regs, priv->aligned_buffer, pid,
 				     in, (char *)buffer + done, num_packets,
-				     xfer_len, &actual_len);
+				     xfer_len, &actual_len, odd_frame);
 
 		hcint = readl(&hc_regs->hcint);
 		if (complete_split) {
 			stop_transfer = 0;
-			if (hcint & DWC2_HCINT_NYET)
+			if (hcint & DWC2_HCINT_NYET) {
 				ret = 0;
-			else
+				int frame_num = DWC2_HFNUM_MAX_FRNUM &
+						readl(&host_regs->hfnum);
+				if (((frame_num - ssplit_frame_num) &
+				    DWC2_HFNUM_MAX_FRNUM) > 4)
+					ret = -EAGAIN;
+			} else
 				complete_split = 0;
 		} else if (do_split) {
 			if (hcint & DWC2_HCINT_ACK) {
+				ssplit_frame_num = DWC2_HFNUM_MAX_FRNUM &
+						   readl(&host_regs->hfnum);
 				ret = 0;
 				complete_split = 1;
 			}