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; + }
maxp = usb_endpoint_maxp(preq->pep->endpoint.desc); total_packet_count = DIV_ROUND_UP(td_total_len, maxp);