The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From bc9a2e226ea95e1699f7590845554de095308b75 Mon Sep 17 00:00:00 2001

From: Thinh Nguyen Thinh.Nguyen@synopsys.com Date: Thu, 6 Aug 2020 19:46:35 -0700 Subject: [PATCH] usb: dwc3: gadget: Handle ZLP for sg requests

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

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index df603a817a98..c2a0f64f8d1e 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -1143,6 +1143,37 @@ static void dwc3_prepare_one_trb_sg(struct dwc3_ep *dep, req->request.short_not_ok, req->request.no_interrupt, req->request.is_last); + } 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, + req->request.is_last); + + /* 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, + req->request.is_last); + } } else { dwc3_prepare_one_trb(dep, req, trb_length, chain, i); }