RE: [PATCH] usb: cdnsp: Fixed setting last_trb incorrectly

[Pawel Laszczak]

>
>From: Jing Leng <jleng@xxxxxxxxxxxxx>
>
>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@xxxxxxxxxxxxx>

Acked-by: Pawel Laszczak <pawell@xxxxxxxxxxx>

>---
> 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