>On Mon, Nov 7, 2022 at 1:39 PM Pawel Laszczak <pawell@xxxxxxxxxxx> >wrote: >> >> > >> > >> >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 >> > >This one is my question. How below condition is true for your case 1: > > if (!more_trbs_coming || (transferred == 0 && trb_buff_len == 0) || > trb_buff_len == td_total_len) For TRB1: more_trbs_coming = true transferred == 0 && trb_buff_len == 0 - false - it does not matter in this case trb_buff_len == td_total_len - true so whole condition is true. Because more_trb_comming = true so: if (more_trbs_coming) return 1; returns TD_SIZE = 1 For TRB2 - ZLP: more_trbs_coming = false transferred == 0 && trb_buff_len == 0 - false - it does not matter in this case trb_buff_len == td_total_len - true Because more_trb_comming = false so function returns TD_SIZE = 0 for last ZLP trb. Pawel > >Peter > > > >> >> 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