patch "usb: dwc3: gadget: Fix handling ZLP" added to usb-linus

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    usb: dwc3: gadget: Fix handling ZLP

to my usb git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


From d2ee3ff79e6a3d4105e684021017d100524dc560 Mon Sep 17 00:00:00 2001
From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Date: Thu, 6 Aug 2020 19:46:29 -0700
Subject: usb: dwc3: gadget: Fix handling ZLP

The usb_request->zero doesn't apply for isoc. Also, if we prepare a
0-length (ZLP) TRB for the OUT direction, we need to prepare an extra
TRB to pad up to the MPS alignment. Use the same bounce buffer for the
ZLP TRB and the extra pad TRB.

Cc: <stable@vger.kernel.org> # v4.5+
Fixes: d6e5a549cc4d ("usb: dwc3: simplify ZLP handling")
Fixes: 04c03d10e507 ("usb: dwc3: gadget: handle request->zero")
Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
---
 drivers/usb/dwc3/gadget.c | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index f9231253cbed..df603a817a98 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1199,6 +1199,7 @@ static void dwc3_prepare_one_trb_linear(struct dwc3_ep *dep,
 				req->request.no_interrupt,
 				req->request.is_last);
 	} else if (req->request.zero && req->request.length &&
+		   !usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
 		   (IS_ALIGNED(req->request.length, maxp))) {
 		struct dwc3	*dwc = dep->dwc;
 		struct dwc3_trb	*trb;
@@ -1208,14 +1209,25 @@ static void dwc3_prepare_one_trb_linear(struct dwc3_ep *dep,
 		/* prepare normal TRB */
 		dwc3_prepare_one_trb(dep, req, length, true, 0);
 
-		/* Now prepare one extra TRB to handle ZLP */
+		/* Prepare one extra TRB to handle ZLP */
 		trb = &dep->trb_pool[dep->trb_enqueue];
 		req->num_trbs++;
 		__dwc3_prepare_one_trb(dep, trb, dwc->bounce_addr, 0,
-				false, 1, req->request.stream_id,
+				!req->direction, 1, req->request.stream_id,
 				req->request.short_not_ok,
 				req->request.no_interrupt,
 				req->request.is_last);
+
+		/* Prepare one more TRB to handle MPS alignment for OUT */
+		if (!req->direction) {
+			trb = &dep->trb_pool[dep->trb_enqueue];
+			req->num_trbs++;
+			__dwc3_prepare_one_trb(dep, trb, dwc->bounce_addr, maxp,
+					       false, 1, req->request.stream_id,
+					       req->request.short_not_ok,
+					       req->request.no_interrupt,
+					       req->request.is_last);
+		}
 	} else {
 		dwc3_prepare_one_trb(dep, req, length, false, 0);
 	}
@@ -2690,8 +2702,17 @@ static int dwc3_gadget_ep_cleanup_completed_request(struct dwc3_ep *dep,
 				status);
 
 	if (req->needs_extra_trb) {
+		unsigned int maxp = usb_endpoint_maxp(dep->endpoint.desc);
+
 		ret = dwc3_gadget_ep_reclaim_trb_linear(dep, req, event,
 				status);
+
+		/* Reclaim MPS padding TRB for ZLP */
+		if (!req->direction && req->request.zero && req->request.length &&
+		    !usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
+		    (IS_ALIGNED(req->request.length, maxp)))
+			ret = dwc3_gadget_ep_reclaim_trb_linear(dep, req, event, status);
+
 		req->needs_extra_trb = false;
 	}
 
-- 
2.28.0