linux-kernel - [PATCH v2 7/8] usb: dwc3: Check for IOC/LST bit in both event->status and TRB->ctrl fields

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Date:   Fri, 17 Aug 2018 17:54:54 +0530
From:   Anurag Kumar Vulisha <anurag.kumar.vulisha@...inx.com>
To:     <balbi@...nel.org>, <gregkh@...uxfoundation.org>
CC:     <v.anuragkumar@...il.com>, <linux-usb@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        Anurag Kumar Vulisha <anurag.kumar.vulisha@...inx.com>
Subject: [PATCH v2 7/8] usb: dwc3: Check for IOC/LST bit in both event->status and TRB->ctrl fields

The present code in dwc3_gadget_ep_reclaim_completed_trb() will check
for IOC/LST bit in the event->status and returns if IOC/LST bit is
set. This logic doesn't work if multiple TRBs are queued per
request and the IOC/LST bit is set on the last TRB of that request.
Consider an example where a queued request has multiple queued TRBs
and IOC/LST bit is set only for the last TRB. In this case, the Core
generates XferComplete/XferInProgress events only for the last TRB
(since IOC/LST are set only for the last TRB). As per the logic in
dwc3_gadget_ep_reclaim_completed_trb() event->status is checked for
IOC/LST bit and returns on the first TRB. This makes the remaining
TRBs left unhandled.
To aviod this, changed the code to check for IOC/LST bits in both
event->status & TRB->ctrl. This patch does the same.

Signed-off-by: Anurag Kumar Vulisha <anurag.kumar.vulisha@...inx.com>
---
 Changes in v2:
	1. None
---
 drivers/usb/dwc3/gadget.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 3af55f8..1b1bc14 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2290,7 +2290,12 @@ static int dwc3_gadget_ep_reclaim_completed_trb(struct dwc3_ep *dep,
 	if (event->status & DEPEVT_STATUS_SHORT && !chain)
 		return 1;

-	if (event->status & (DEPEVT_STATUS_IOC | DEPEVT_STATUS_LST))
+	if ((event->status & DEPEVT_STATUS_IOC) &&
+	    (trb->ctrl & DWC3_TRB_CTRL_IOC))
+		return 1;
+
+	if ((event->status & DEPEVT_STATUS_LST) &&
+	    (trb->ctrl & DWC3_TRB_CTRL_LST))
 		return 1;

 	return 0;
-- 
2.1.1