On Tue, Nov 15, 2022 at 5:22 PM Pawel Laszczak <pawell@xxxxxxxxxxx> wrote:
>
> Patch modifies the TD_SIZE in TRB before ZLP TRB.
> The TD_SIZE in TRB before ZLP TRB must be set to 1 to force
> processing ZLP TRB by controller.
>
> cc: <stable@xxxxxxxxxxxxxxx>
> Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
> Signed-off-by: Pawel Laszczak <pawell@xxxxxxxxxxx>
> ---
> v2:
> - returned value for last TRB must be 0
> v3:
> - fix issue for request->length > 64KB
>
> drivers/usb/cdns3/cdnsp-ring.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/usb/cdns3/cdnsp-ring.c b/drivers/usb/cdns3/cdnsp-ring.c
> index 794e413800ae..86e1141e150f 100644
> --- a/drivers/usb/cdns3/cdnsp-ring.c
> +++ b/drivers/usb/cdns3/cdnsp-ring.c
> @@ -1763,10 +1763,15 @@ static u32 cdnsp_td_remainder(struct cdnsp_device *pdev,
> int trb_buff_len,
> unsigned int td_total_len,
> struct cdnsp_request *preq,
> - bool more_trbs_coming)
> + bool more_trbs_coming,
> + bool zlp)
> {
> u32 maxp, total_packet_count;
>
> + /* Before ZLP driver needs set TD_SIZE = 1. */
> + if (zlp)
> + return 1;
> +
Pawel, with your change, the TD_SIZE is 1 or 0, but not like the
kernel doc defined like below:
/*
* TD size is the number of max packet sized packets remaining in the TD
* (*not* including this TRB).
*
* Total TD packet count = total_packet_count =
* DIV_ROUND_UP(TD size in bytes / wMaxPacketSize)
*
* Packets transferred up to and including this TRB = packets_transferred =
* rounddown(total bytes transferred including this TRB / wMaxPacketSize)
*
* TD size = total_packet_count - packets_transferred
*
* It must fit in bits 21:17, so it can't be bigger than 31.
* This is taken care of in the TRB_TD_SIZE() macro
*
* The last TRB in a TD must have the TD size set to zero.
*/
Peter
> /* One TRB with a zero-length data packet. */
> if (!more_trbs_coming || (transferred == 0 && trb_buff_len == 0) ||
> trb_buff_len == td_total_len)
> @@ -1960,7 +1965,8 @@ int cdnsp_queue_bulk_tx(struct cdnsp_device *pdev, struct cdnsp_request *preq)
> /* Set the TRB length, TD size, and interrupter fields. */
> remainder = cdnsp_td_remainder(pdev, enqd_len, trb_buff_len,
> full_len, preq,
> - more_trbs_coming);
> + more_trbs_coming,
> + zero_len_trb);
>
> length_field = TRB_LEN(trb_buff_len) | TRB_TD_SIZE(remainder) |
> TRB_INTR_TARGET(0);
> @@ -2025,7 +2031,7 @@ int cdnsp_queue_ctrl_tx(struct cdnsp_device *pdev, struct cdnsp_request *preq)
>
> if (preq->request.length > 0) {
> remainder = cdnsp_td_remainder(pdev, 0, preq->request.length,
> - preq->request.length, preq, 1);
> + preq->request.length, preq, 1, 0);
>
> length_field = TRB_LEN(preq->request.length) |
> TRB_TD_SIZE(remainder) | TRB_INTR_TARGET(0);
> @@ -2225,7 +2231,7 @@ static int cdnsp_queue_isoc_tx(struct cdnsp_device *pdev,
> /* Set the TRB length, TD size, & interrupter fields. */
> remainder = cdnsp_td_remainder(pdev, running_total,
> trb_buff_len, td_len, preq,
> - more_trbs_coming);
> + more_trbs_coming, 0);
>
> length_field = TRB_LEN(trb_buff_len) | TRB_INTR_TARGET(0);
>
> --
> 2.25.1
>
