From 23ce756d92dc2cd1746338f3d6197ee2ac3066b4 Mon Sep 17 00:00:00 2001
From: William Wu <william.wu@rock-chips.com>
Date: Fri, 7 May 2021 11:02:38 +0800
Subject: [PATCH] usb: dwc3: gadget: support tx fifos resize for superspeed

This patch supports tx fifos resize for superspeed, if needed.
And it limits the maximum fifo size to six times of the endpoint
maxpacket because of the limited dwc3 hardware fifos.

Change-Id: I69af3419ecdc7f5d0869ba5d2dce041e4d90fae7
Signed-off-by: William Wu <william.wu@rock-chips.com>
---
 drivers/usb/dwc3/gadget.c | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index df0aeae53b02..eec38152ed3e 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -172,8 +172,7 @@ static int dwc3_gadget_resize_tx_fifos(struct dwc3 *dwc)
 	 * during controller transfer data, it may cause controller
 	 * run into abnormal and unrecoverable state.
 	 */
-	if (!dwc->needs_fifo_resize || dwc->fifo_resize_status ||
-	    dwc->gadget.speed > USB_SPEED_HIGH)
+	if (!dwc->needs_fifo_resize || dwc->fifo_resize_status)
 		return 0;
 
 	num_in_eps = DWC3_NUM_IN_EPS(&dwc->hwparams);
@@ -208,7 +207,10 @@ static int dwc3_gadget_resize_tx_fifos(struct dwc3 *dwc)
 			}
 
 			mult = 1;
-			maxpacket = 64;
+			if (dwc->gadget.speed <= USB_SPEED_HIGH)
+				maxpacket = 64;
+			else
+				maxpacket = 512;
 			break;
 		case USB_ENDPOINT_XFER_ISOC:
 			if (!dep->endpoint.caps.type_iso) {
@@ -222,9 +224,15 @@ static int dwc3_gadget_resize_tx_fifos(struct dwc3 *dwc)
 			 * to get better performance and more compliance
 			 * with bus latency.
 			 */
-			mult = dep->endpoint.mult;
-			mult = mult > 0 ? mult * 2 : 3;
 			maxpacket = dep->endpoint.maxpacket;
+			if (dwc->gadget.speed <= USB_SPEED_HIGH)
+				mult = dep->endpoint.mult;
+			else
+				mult = dep->endpoint.mult *
+				       dep->endpoint.maxburst;
+			mult = mult > 0 ? mult * 2 : 3;
+			if (mult > 6)
+				mult = 6;
 			break;
 		case USB_ENDPOINT_XFER_BULK:
 			if (!dep->endpoint.caps.type_bulk) {
@@ -238,7 +246,16 @@ static int dwc3_gadget_resize_tx_fifos(struct dwc3 *dwc)
 			 * better transmission performance.
 			 */
 			mult = 3;
-			maxpacket = 512;
+			if (dwc->gadget.speed <= USB_SPEED_HIGH) {
+				maxpacket = 512;
+			} else {
+				if (dep->endpoint.maxburst > mult) {
+					mult = dep->endpoint.maxburst;
+					if (mult > 6)
+						mult = 6;
+				}
+				maxpacket = 1024;
+			}
 			break;
 		case USB_ENDPOINT_XFER_INT:
 			/* Bulk endpoints handle interrupt transfers. */