> > >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? For last non-ZLP TRB TD_SIZE should be 0 or 1. We have three casess: 1. TRB1 - length > 1 TRb2 - ZLP In this case TRB1 should have set TD_SIZE = 1. In this case the condition if (more_trbs_coming) return 1; returns TD_SIZE=1. In this case more_trb_comming for TRB1 is 1 and for TRB2 is 0 2. TRB1 - length >1 and we don't except ZLP In this case TD_SIZE should be set to 0 for TRB1 and function returns 0, more_trbs_comming for TRB1 will be set to 0. 3 More TRBs without ZLP: e.g. TRB1 - length > 0, more_trbs_comming = 1 - TD_SIZE > 0 TRB2 - length > 0, more_trbs_comming = 1 - TD_SIZE > 0 TRB3 - length >= 0, more_trbs_comming = 0 - TD_SIZE = 0 Pawel > >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 Regards, Pawel Laszczak