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@vger.kernel.org Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver") Signed-off-by: Pawel Laszczak pawell@cadence.com
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.
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