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From:   3090101217@zju.edu.cn
To:     pawell@cadence.com, gregkh@linuxfoundation.org,
        peter.chen@kernel.org
Cc:     linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jing Leng <jleng@ambarella.com>
Subject: [PATCH] usb: cdnsp: Fixed setting last_trb incorrectly
Date:   Thu,  9 Jun 2022 10:11:34 +0800
Message-Id: <20220609021134.1606-1-3090101217@zju.edu.cn>
Precedence: bulk

From: Jing Leng <jleng@ambarella.com>

When ZLP occurs in bulk transmission, currently cdnsp will set last_trb
for the last two TRBs, it will trigger an error "ERROR Transfer event TRB
DMA ptr not part of current TD ...".

Fixes: e913aada0683 ("usb: cdnsp: Fixed issue with ZLP")
Signed-off-by: Jing Leng <jleng@ambarella.com>
---
 drivers/usb/cdns3/cdnsp-ring.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/cdns3/cdnsp-ring.c b/drivers/usb/cdns3/cdnsp-ring.c
index e45c3d6e1536..794e413800ae 100644
--- a/drivers/usb/cdns3/cdnsp-ring.c
+++ b/drivers/usb/cdns3/cdnsp-ring.c
@@ -1941,13 +1941,16 @@ int cdnsp_queue_bulk_tx(struct cdnsp_device *pdev, struct cdnsp_request *preq)
 		}
 
 		if (enqd_len + trb_buff_len >= full_len) {
-			if (need_zero_pkt)
-				zero_len_trb = !zero_len_trb;
-
-			field &= ~TRB_CHAIN;
-			field |= TRB_IOC;
-			more_trbs_coming = false;
-			preq->td.last_trb = ring->enqueue;
+			if (need_zero_pkt && !zero_len_trb) {
+				zero_len_trb = true;
+			} else {
+				zero_len_trb = false;
+				field &= ~TRB_CHAIN;
+				field |= TRB_IOC;
+				more_trbs_coming = false;
+				need_zero_pkt = false;
+				preq->td.last_trb = ring->enqueue;
+			}
 		}
 
 		/* Only set interrupt on short packet for OUT endpoints. */
@@ -1962,7 +1965,7 @@ int cdnsp_queue_bulk_tx(struct cdnsp_device *pdev, struct cdnsp_request *preq)
 		length_field = TRB_LEN(trb_buff_len) | TRB_TD_SIZE(remainder) |
 			TRB_INTR_TARGET(0);
 
-		cdnsp_queue_trb(pdev, ring, more_trbs_coming | zero_len_trb,
+		cdnsp_queue_trb(pdev, ring, more_trbs_coming,
 				lower_32_bits(send_addr),
 				upper_32_bits(send_addr),
 				length_field,
-- 
2.17.1