On 22-10-27 08:46:17, Pawel Laszczak wrote:
>
> >
> >On 22-10-24 10:04:35, 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>
> >>
> >> ---
> >> Changelog:
> >> v2:
> >> - returned value for last TRB must be 0
> >>
> >> drivers/usb/cdns3/cdnsp-ring.c | 7 ++++++-
> >> 1 file changed, 6 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/usb/cdns3/cdnsp-ring.c
> >> b/drivers/usb/cdns3/cdnsp-ring.c index 04dfcaa08dc4..aa79bce89d8a
> >> 100644
> >> --- a/drivers/usb/cdns3/cdnsp-ring.c
> >> +++ b/drivers/usb/cdns3/cdnsp-ring.c
> >> @@ -1769,8 +1769,13 @@ static u32 cdnsp_td_remainder(struct
> >> cdnsp_device *pdev,
> >>
> >> /* One TRB with a zero-length data packet. */
> >> if (!more_trbs_coming || (transferred == 0 && trb_buff_len == 0) ||
> >> - trb_buff_len == td_total_len)
> >> + trb_buff_len == td_total_len) {
> >> + /* Before ZLP driver needs set TD_SIZE=1. */
> >> + if (more_trbs_coming)
> >> + return 1;
> >> +
> >> return 0;
> >> + }
> >
> >Does that fix the issue you want at bulk transfer, which has zero-length packet
> >at the last packet? It seems not align with your previous fix.
> >Would you mind explaining more?
>
> Value returned by function cdnsp_td_remainder is used
> as TD_SIZE in TRB.
>
> The last TRB in TD should have TD_SIZE=0, so trb for ZLP should have
> set also TD_SIZE=0. If driver set TD_SIZE=0 on before the last one
> TRB then the controller stops the transfer and ignore trb for ZLP packet.
>
> To fix this, the driver in such case must set TD_SIZE = 1
> before the last TRB.
if (!more_trbs_coming || (transferred == 0 && trb_buff_len == 0) ||
- trb_buff_len == td_total_len)
+ trb_buff_len == td_total_len) {
+ /* Before ZLP driver needs set TD_SIZE=1. */
+ if (more_trbs_coming)
+ return 1;
+
return 0;
+ }
How your above fix could return TD_SIZE as 1 for last non-ZLP TRB?
Which conditions are satisfied?
Peter
> e.g.
>
> TD -> TRB1 transfer_length = 64KB, TD_SIZE =0
> TRB2 transfer_length =0, TD_SIZE = 0 - controller will
> ignore this transfer and stop transfer on previous one
>
> TD -> TRB1 transfer_length = 64KB, TD_SIZE =1
> TRB2 transfer_length =0, TD_SIZE = 0 - controller will
> execute this trb and send ZLP
>
> As you noticed previously, previous fix for last TRB returned
> TD_SIZE = 1 in some cases.
> Previous fix was working correct but was not compliance with
> controller specification.
>
> >
> >>
> >> maxp = usb_endpoint_maxp(preq->pep->endpoint.desc);
> >> total_packet_count = DIV_ROUND_UP(td_total_len, maxp);
> >> --
> >> 2.25.1
> >>
> >
> >--
> >
>
> Thanks,
> Pawel Laszczak
--
Thanks,
Peter Chen
