[PATCH 5.4 203/214] usb: dwc3: gadget: Handle ZLP for sg requests

Greg Kroah-Hartman
2020-09-01T15:36:27Z

From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>

[ Upstream commit bc9a2e226ea95e1699f7590845554de095308b75 ]

Currently dwc3 doesn't handle usb_request->zero for SG requests. This
change checks and prepares extra TRBs for the ZLP for SG requests.

Cc: <stable@vger.kernel.org> # v4.5+
Fixes: 04c03d10e507 ("usb: dwc3: gadget: handle request->zero")
Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/dwc3/gadget.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 8e67591df76be..4225544342519 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1104,6 +1104,35 @@ static void dwc3_prepare_one_trb_sg(struct dwc3_ep *dep,
req->request.stream_id,
req->request.short_not_ok,
req->request.no_interrupt);
+ } else if (req->request.zero && req->request.length &&
+ !usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
+ !rem && !chain) {
+ struct dwc3 *dwc = dep->dwc;
+ struct dwc3_trb *trb;
+
+ req->needs_extra_trb = true;
+
+ /* Prepare normal TRB */
+ dwc3_prepare_one_trb(dep, req, trb_length, true, i);
+
+ /* Prepare one extra TRB to handle ZLP */
+ trb = &dep->trb_pool[dep->trb_enqueue];
+ req->num_trbs++;
+ __dwc3_prepare_one_trb(dep, trb, dwc->bounce_addr, 0,
+ !req->direction, 1,
+ req->request.stream_id,
+ req->request.short_not_ok,
+ req->request.no_interrupt);
+
+ /* Prepare one more TRB to handle MPS alignment */
+ if (!req->direction) {
+ trb = &dep->trb_pool[dep->trb_enqueue];
+ req->num_trbs++;
+ __dwc3_prepare_one_trb(dep, trb, dwc->bounce_addr, maxp,
+ false, 1, req->request.stream_id,
+ req->request.short_not_ok,
+ req->request.no_interrupt);
+ }
} else {
dwc3_prepare_one_trb(dep, req, trb_length, chain, i);
}
--
2.25.1