From ba3a51ac32ebcf8d0a54b37f1af268ad8a31c52f Mon Sep 17 00:00:00 2001
From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Date: Thu, 2 Aug 2018 20:17:16 -0700
Subject: [PATCH] usb: dwc3: gadget: Properly check last unaligned/zero chain TRB
Git-commit: ba3a51ac32ebcf8d0a54b37f1af268ad8a31c52f
Patch-mainline: v4.20-rc4
References: bsc#1051510

Current check for the last extra TRB for zero and unaligned transfers
does not account for isoc OUT. The last TRB of the Buffer Descriptor for
isoc OUT transfers will be retired with HWO=0. As a result, we won't
return early. The req->remaining will be updated to include the BUFSIZ
count of the extra TRB, and the actual number of transferred bytes
calculation will be wrong.

To fix this, check whether it's a short or zero packet and the last TRB
chain bit to return early.

Fixes: c6267a51639b ("usb: dwc3: gadget: align transfers to wMaxPacketSize")
Cc: <stable@vger.kernel.org>
Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/usb/dwc3/gadget.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 679c12e14522..06e22afdf3d1 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2259,7 +2259,7 @@ static int dwc3_gadget_ep_reclaim_completed_trb(struct dwc3_ep *dep,
 	 * with one TRB pending in the ring. We need to manually clear HWO bit
 	 * from that TRB.
 	 */
-	if ((req->zero || req->unaligned) && (trb->ctrl & DWC3_TRB_CTRL_HWO)) {
+	if ((req->zero || req->unaligned) && !(trb->ctrl & DWC3_TRB_CTRL_CHN)) {
 		trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
 		return 1;
 	}
-- 
2.19.1