>
>
>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
>Peter
>
>> +
>> + return remainder;
>> }
>>
>> static int cdnsp_align_td(struct cdnsp_device *pdev,
>> --
>> 2.25.1
>>
>
>--
>
>Thanks,
>Peter Chen
Regards,
Pawel Laszczak
