commit 0c4b0656c1e7d4d965a753e15b4d63872b596d11
author Stefan Brüns <stefan.bruens@rwth-aachen.de> Sun Jan 17 04:09:55 2016 +0100
committer Marek Vasut <marex@denx.de> Sat Jan 23 16:21:11 2016 +0100
tree 4072a5c131399e70437c83e703d65b2244334b20
parent 2e194e242d5035587983329bec3d495bc815fe09

usb: dwc2: Implement SPLIT transaction support

In contrast to non-SPLIT transfers each transaction has to be submitted
as an individual chunk.
The transaction state machine proceeds from SSPLIT to CSPLIT if the ACK
flag is set. CSPLIT has to be repeated while NYET is set.

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 7fbbc4b..413845c 100644
--- a/drivers/usb/host/dwc2.c
+++ b/drivers/usb/host/dwc2.c
@@ -837,6 +837,8 @@
 	int eptype = dwc2_eptype[usb_pipetype(pipe)];
 	int done = 0;
 	int ret = 0;
+	int do_split = 0;
+	int complete_split = 0;
 	uint32_t xfer_len;
 	uint32_t num_packets;
 	int stop_transfer = 0;
@@ -859,8 +861,26 @@
 	dwc_otg_hc_init(regs, DWC2_HC_CHANNEL, dev, devnum, ep, in,
 			eptype, max);
 
+	/* Check if the target is a FS/LS device behind a HS hub */
+	if (dev->speed != USB_SPEED_HIGH) {
+		uint8_t hub_addr;
+		uint8_t hub_port;
+		uint32_t hprt0 = readl(&regs->hprt0);
+		if ((hprt0 & DWC2_HPRT0_PRTSPD_MASK) ==
+		     DWC2_HPRT0_PRTSPD_HIGH) {
+			usb_find_usb2_hub_address_port(dev, &hub_addr,
+						       &hub_port);
+			dwc_otg_hc_init_split(hc_regs, hub_addr, hub_port);
+
+			do_split = 1;
+			num_packets = 1;
+			max_xfer_len = max;
+		}
+	}
+
 	do {
 		int actual_len = 0;
+		uint32_t hcint;
 		xfer_len = len - done;
 
 		if (xfer_len > max_xfer_len)
@@ -870,10 +890,29 @@
 		else
 			num_packets = 1;
 
+		if (complete_split)
+			setbits_le32(&hc_regs->hcsplt, DWC2_HCSPLT_COMPSPLT);
+		else if (do_split)
+			clrbits_le32(&hc_regs->hcsplt, DWC2_HCSPLT_COMPSPLT);
+
 		ret = transfer_chunk(hc_regs, priv->aligned_buffer, pid,
 				     in, (char *)buffer + done, num_packets,
 				     xfer_len, &actual_len);
 
+		hcint = readl(&hc_regs->hcint);
+		if (complete_split) {
+			stop_transfer = 0;
+			if (hcint & DWC2_HCINT_NYET)
+				ret = 0;
+			else
+				complete_split = 0;
+		} else if (do_split) {
+			if (hcint & DWC2_HCINT_ACK) {
+				ret = 0;
+				complete_split = 1;
+			}
+		}
+
 		if (ret)
 			break;
 
@@ -882,7 +921,11 @@
 
 		done += actual_len;
 
-	} while ((done < len) && !stop_transfer);
+	/* Transactions are done when when either all data is transferred or
+	 * there is a short transfer. In case of a SPLIT make sure the CSPLIT
+	 * is executed.
+	 */
+	} while (((done < len) && !stop_transfer) || complete_split);
 
 	writel(0, &hc_regs->hcintmsk);
 	writel(0xFFFFFFFF, &hc_regs->hcint);
@@ -925,31 +968,39 @@
 					     setup);
 	}
 
+	/* SETUP stage */
 	pid = DWC2_HC_PID_SETUP;
-	ret = chunk_msg(priv, dev, pipe, &pid, 0, setup, 8);
+	do {
+		ret = chunk_msg(priv, dev, pipe, &pid, 0, setup, 8);
+	} while (ret == -EAGAIN);
 	if (ret)
 		return ret;
 
+	/* DATA stage */
+	act_len = 0;
 	if (buffer) {
 		pid = DWC2_HC_PID_DATA1;
-		ret = chunk_msg(priv, dev, pipe, &pid, usb_pipein(pipe), buffer,
-				len);
+		do {
+			ret = chunk_msg(priv, dev, pipe, &pid, usb_pipein(pipe),
+					buffer, len);
+			act_len += dev->act_len;
+			buffer += dev->act_len;
+			len -= dev->act_len;
+		} while (ret == -EAGAIN);
 		if (ret)
 			return ret;
-		act_len = dev->act_len;
-	} /* End of DATA stage */
-	else
-		act_len = 0;
-
-	/* STATUS stage */
-	if ((len == 0) || usb_pipeout(pipe))
+		status_direction = usb_pipeout(pipe);
+	} else {
+		/* No-data CONTROL always ends with an IN transaction */
 		status_direction = 1;
-	else
-		status_direction = 0;
+	}
 
+	/* STATUS stage */
 	pid = DWC2_HC_PID_DATA1;
-	ret = chunk_msg(priv, dev, pipe, &pid, status_direction,
-			priv->status_buffer, 0);
+	do {
+		ret = chunk_msg(priv, dev, pipe, &pid, status_direction,
+				priv->status_buffer, 0);
+	} while (ret == -EAGAIN);
 	if (ret)
 		return ret;