>> >
>> >On 22-10-19 02:07:17, Pawel Laszczak 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>
>> >> ---
>> >> drivers/usb/cdns3/cdnsp-ring.c | 15 ++++++++-------
>> >> 1 file changed, 8 insertions(+), 7 deletions(-)
>> >>
>> >> diff --git a/drivers/usb/cdns3/cdnsp-ring.c
>> >> b/drivers/usb/cdns3/cdnsp-ring.c index 794e413800ae..4809d0e894bb
>> >> 100644
>> >> --- a/drivers/usb/cdns3/cdnsp-ring.c
>> >> +++ b/drivers/usb/cdns3/cdnsp-ring.c
>> >> @@ -1765,18 +1765,19 @@ static u32 cdnsp_td_remainder(struct
>> >cdnsp_device *pdev,
>> >> struct cdnsp_request *preq,
>> >> bool more_trbs_coming)
>> >> {
>> >> - u32 maxp, total_packet_count;
>> >> -
>> >> - /* One TRB with a zero-length data packet. */
>> >> - if (!more_trbs_coming || (transferred == 0 && trb_buff_len == 0) ||
>> >> - trb_buff_len == td_total_len)
>> >> - return 0;
>> >> + u32 maxp, total_packet_count, remainder;
>> >>
>> >> maxp = usb_endpoint_maxp(preq->pep->endpoint.desc);
>> >> total_packet_count = DIV_ROUND_UP(td_total_len, maxp);
>> >>
>> >> /* Queuing functions don't count the current TRB into transferred. */
>> >> - return (total_packet_count - ((transferred + trb_buff_len) / maxp));
>> >> + remainder = (total_packet_count - ((transferred + trb_buff_len) /
>> >> +maxp));
>> >> +
>> >> + /* Before ZLP driver needs set TD_SIZE=1. */
>> >> + if (!remainder && more_trbs_coming)
>> >> + remainder = 1;
>> >
>> >Without ZLP, TD_SIZE = 0 for the last TRB.
>> >With ZLP, TD_SIZE = 1 for current TRB, and TD_SIZE = 0 for the next
>> >TRB (the last zero-length packet) right?
>>
>> Yes, you have right.
>>
>
>Pawel, With your changes, the return value is 1 for function
>cdnsp_queue_ctrl_tx. Without your changes, it is 0, something wrong?
>
Yes you have right.
It does not cause a problem, but it's not according with controller specification.
I posted the fixed version of this patch.
Thanks,
Pawel
