Bugfix: Use only one PTD for one endpoint

Original isp116x-hcd code prepared multiple PTDs for longer than 16
byte transfers for one endpoint. That is unnecessary because the
ISP116x is able to split long data from one PTD into multiple
transactions based on the buffer size of the endpoint. It also caused
serious problems if the endpoint NAKed some of the transactions. In
that case ISP116x wouldn't notice that the other PTDs were for the same
endpoint and would try the other PTDs possibly out of order. That would
break the whole transfer.

This patch makes isp116x_submit_job to use one PTD for one transfer.

Signed-off-by: Timo Ketola <timo.ketola@exertus.fi>
Signed-off-by: Markus Klotzbuecher <mk@denx.de>

drivers/isp116x-hcd.c

@@ -113,9 +113,9 @@ static const char hcd_name[] = "isp116x-hcd";
 
 struct isp116x isp116x_dev;
 struct isp116x_platform_data isp116x_board;
-int got_rhsc = 0;		/* root hub status change */
+static int got_rhsc;		/* root hub status change */
 struct usb_device *devgone;	/* device which was disconnected */
-int rh_devnum = 0;		/* address of Root Hub endpoint */
+static int rh_devnum;		/* address of Root Hub endpoint */
 
 /* ------------------------------------------------------------------------- */
 
@@ -522,11 +522,13 @@ static int unpack_fifo(struct isp116x *isp116x, struct usb_device *dev,
 		done += PTD_GET_LEN(&ptd[i]);
 
 		cc = PTD_GET_CC(&ptd[i]);
-		if (cc == TD_DATAUNDERRUN) {	/* underrun is no error... */
-			DBG("allowed data underrun");
-			cc = TD_CC_NOERROR;
-		}
-		if (cc != TD_CC_NOERROR && ret == TD_CC_NOERROR)
+
+		/* Data underrun means basically that we had more buffer space than
+		 * the function had data. It is perfectly normal but upper levels have
+		 * to know how much we actually transferred.
+		 */
+		if (cc == TD_NOTACCESSED ||
+				(cc != TD_CC_NOERROR && (ret == TD_CC_NOERROR || ret == TD_DATAUNDERRUN)))
 			ret = cc;
 	}
 
@@ -592,11 +594,19 @@ static int isp116x_interrupt(struct isp116x *isp116x)
 	return ret;
 }
 
-#define PTD_NUM			64	/* it should be enougth... */
-struct ptd ptd[PTD_NUM];
+/* With one PTD we can transfer almost 1K in one go;
+ * HC does the splitting into endpoint digestible transactions
+ */
+struct ptd ptd[1];
+
 static inline int max_transfer_len(struct usb_device *dev, unsigned long pipe)
 {
-	return min(PTD_NUM * usb_maxpacket(dev, pipe), PTD_NUM * 16);
+	unsigned mpck = usb_maxpacket(dev, pipe);
+
+	/* One PTD can transfer 1023 bytes but try to always
+	 * transfer multiples of endpoint buffer size
+	 */
+	return 1023 / mpck * mpck;
 }
 
 /* Do an USB transfer
@@ -610,13 +620,21 @@ static int isp116x_submit_job(struct usb_device *dev, unsigned long pipe,
 	int max = usb_maxpacket(dev, pipe);
 	int dir_out = usb_pipeout(pipe);
 	int speed_low = usb_pipeslow(pipe);
-	int i, done, stat, timeout, cc;
-	int retries = 10;
+	int i, done = 0, stat, timeout, cc;
+
+	/* 500 frames or 0.5s timeout when function is busy and NAKs transactions for a while */
+	int retries = 500;
 
 	DBG("------------------------------------------------");
 	dump_msg(dev, pipe, buffer, len, "SUBMIT");
 	DBG("------------------------------------------------");
 
+	if (len >= 1024) {
+		ERR("Too big job");
+		dev->status = USB_ST_CRC_ERR;
+		return -1;
+	}
+
 	if (isp116x->disabled) {
 		ERR("EPIPE");
 		dev->status = USB_ST_CRC_ERR;
@@ -653,29 +671,15 @@ static int isp116x_submit_job(struct usb_device *dev, unsigned long pipe,
 	isp116x_write_reg32(isp116x, HCINTSTAT, 0xff);
 
 	/* Prepare the PTD data */
-	done = 0;
-	i = 0;
-	do {
-		ptd[i].count = PTD_CC_MSK | PTD_ACTIVE_MSK |
-		    PTD_TOGGLE(usb_gettoggle(dev, epnum, dir_out));
-		ptd[i].mps = PTD_MPS(max) | PTD_SPD(speed_low) | PTD_EP(epnum);
-		ptd[i].len = PTD_LEN(max > len - done ? len - done : max) |
-		    PTD_DIR(dir);
-		ptd[i].faddr = PTD_FA(usb_pipedevice(pipe));
-
-		usb_dotoggle(dev, epnum, dir_out);
-		done += PTD_GET_LEN(&ptd[i]);
-		i++;
-		if (i >= PTD_NUM) {
-			ERR("****** Cannot pack buffer! ******");
-			dev->status = USB_ST_BUF_ERR;
-			return -1;
-		}
-	} while (done < len);
-	ptd[i - 1].mps |= PTD_LAST_MSK;
+	ptd->count = PTD_CC_MSK | PTD_ACTIVE_MSK |
+		PTD_TOGGLE(usb_gettoggle(dev, epnum, dir_out));
+	ptd->mps = PTD_MPS(max) | PTD_SPD(speed_low) | PTD_EP(epnum) | PTD_LAST_MSK;
+	ptd->len = PTD_LEN(len) | PTD_DIR(dir);
+	ptd->faddr = PTD_FA(usb_pipedevice(pipe));
 
+retry_same:
 	/* Pack data into FIFO ram */
-	pack_fifo(isp116x, dev, pipe, ptd, i, buffer, len);
+	pack_fifo(isp116x, dev, pipe, ptd, 1, buffer, len);
 #ifdef EXTRA_DELAY
 	wait_ms(EXTRA_DELAY);
 #endif
@@ -738,17 +742,42 @@ static int isp116x_submit_job(struct usb_device *dev, unsigned long pipe,
 	}
 
 	/* Unpack data from FIFO ram */
-	cc = unpack_fifo(isp116x, dev, pipe, ptd, i, buffer, len);
+	cc = unpack_fifo(isp116x, dev, pipe, ptd, 1, buffer, len);
+
+	i = PTD_GET_COUNT(ptd);
+	done += i;
+	buffer += i;
+	len -= i;
 
-	/* Mmm... sometime we get 0x0f as cc which is a non sense!
-	 * Just retry the transfer...
+	/* There was some kind of real problem; Prepare the PTD again
+	 * and retry from the failed transaction on
 	 */
-	if (cc == 0x0f && retries-- > 0) {
-		usb_dotoggle(dev, epnum, dir_out);
-		goto retry;
+	if (cc && cc != TD_NOTACCESSED && cc != TD_DATAUNDERRUN) {
+		if (retries >= 100) {
+			retries -= 100;
+			/* The chip will have toggled the toggle bit for the failed
+			 * transaction too. We have to toggle it back.
+			 */
+			usb_settoggle(dev, epnum, dir_out, !PTD_GET_TOGGLE(ptd));
+			goto retry;
+		}
+	}
+	/* "Normal" errors; TD_NOTACCESSED would mean in effect that the function have NAKed
+	 * the transactions from the first on for the whole frame. It may be busy and we retry
+	 * with the same PTD. PTD_ACTIVE (and not TD_NOTACCESSED) would mean that some of the
+	 * PTD didn't make it because the function was busy or the frame ended before the PTD
+	 * finished. We prepare the rest of the data and try again.
+	 */
+	else if (cc == TD_NOTACCESSED || PTD_GET_ACTIVE(ptd) || (cc != TD_DATAUNDERRUN && PTD_GET_COUNT(ptd) < PTD_GET_LEN(ptd))) {
+		if (retries) {
+			--retries;
+			if (cc == TD_NOTACCESSED && PTD_GET_ACTIVE(ptd) && !PTD_GET_COUNT(ptd)) goto retry_same;
+			usb_settoggle(dev, epnum, dir_out, PTD_GET_TOGGLE(ptd));
+			goto retry;
+		}
 	}
 
-	if (cc != TD_CC_NOERROR) {
+	if (cc != TD_CC_NOERROR && cc != TD_DATAUNDERRUN) {
 		DBG("****** completition code error %x ******", cc);
 		switch (cc) {
 		case TD_CC_BITSTUFFING:
@@ -766,6 +795,7 @@ static int isp116x_submit_job(struct usb_device *dev, unsigned long pipe,
 		}
 		return -cc;
 	}
+	else usb_settoggle(dev, epnum, dir_out, PTD_GET_TOGGLE(ptd));
 
 	dump_msg(dev, pipe, buffer, len, "SUBMIT(ret)");
 
@@ -1369,6 +1399,8 @@ int usb_lowlevel_init(void)
 
 	DBG("");
 
+	got_rhsc = rh_devnum = 0;
+
 	/* Init device registers addr */
 	isp116x->addr_reg = (u16 *) ISP116X_HCD_ADDR;
 	isp116x->data_reg = (u16 *) ISP116X_HCD_DATA;