usb: dwc3: gadget: Disable CSP for stream OUT ep
Quoted 25 lines · Tejas Joglekar
In stream mode, when fast-forwarding TRBs, the stream number is not cleared causing the new stream to not get assigned. So we don't want controller to carry on transfers when short packet is received. So disable the CSP for stream capable endpoint.
This is based on the 3.30a Programming guide, where table 3-1 device descriptor structure field definitions says for CSP bit If this bit is 0, the controller generates an XferComplete event and remove the stream. So if we keep CSP as 1 then switching between streams would not happen as in stream mode, when fast-forwarding TRBs, the stream number is not cleared causing the new stream to not get assigned.
Signed-off-by Tejas Joglekar <[email protected]>--- drivers/usb/dwc3/gadget.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)drivers/usb/dwc3/gadget.c +0
-0@@ -986,9 +986,15 @@ static void __dwc3_prepare_one_trb(struct dwc3_ep *dep, struct dwc3_trb *trb, usb_endpoint_type(dep->endpoint.desc)); }
drivers/usb/dwc3/gadget.c static void __dwc3_prepare_one_trb(struct dwc3_ep *dep, struct dwc3_trb *trb, · line 995
Quoted 10 lines
drivers/usb/dwc3/gadget.c +6
-2-/* always enable Continue on Short Packet */ +/* +* Enable Continue on Short Packet +* when endpoint is not a stream capable +*/ if (usb_endpoint_dir_out (dep->endpoint.desc)) { - trb->ctrl |=DWC3_TRB_CTRL_CSP ; +if (dep->stream_capable) + trb->ctrl &= ~DWC3_TRB_CTRL_CSP ;
Is this necessary? Or would it be enough to have this as:
if (!dep->stream_capable) trb->ctrl |= DWC3_TRB_CTRL_CSP;