From cf3113d893d4427b166ec8695460efa7aa660923 Mon Sep 17 00:00:00 2001 From: Felipe Balbi Date: Fri, 17 Feb 2017 11:12:44 +0200 Subject: [PATCH] usb: dwc3: gadget: properly increment dequeue pointer on ep_dequeue If request was already started, this means we had to stop the transfer. With that we also need to ignore all TRBs used by the request, however TRBs can only be modified after completion of END_TRANSFER command. So what we have to do here is wait for END_TRANSFER completion and only after that jump over TRBs by clearing HWO and incrementing dequeue pointer. Note that we have 2 possible types of transfers here: i) Linear buffer request ii) SG-list based request SG-list based requests will have r->num_pending_sgs set to a valid number (> 0). Linear requests, normally use a single TRB. For each of these two cases, if r->unaligned flag is set, one extra TRB has been used to align transfer size to wMaxPacketSize. All of these cases need to be taken into consideration so we don't mess up our TRB ring pointers. Tested-by: Janusz Dziedzic Signed-off-by: Felipe Balbi --- drivers/usb/dwc3/gadget.c | 63 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 4db97ecae885..f875b3f4b0ec 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -1342,6 +1342,68 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep, if (r == req) { /* wait until it is processed */ dwc3_stop_active_transfer(dwc, dep->number, true); + + /* + * If request was already started, this means we had to + * stop the transfer. With that we also need to ignore + * all TRBs used by the request, however TRBs can only + * be modified after completion of END_TRANSFER + * command. So what we do here is that we wait for + * END_TRANSFER completion and only after that, we jump + * over TRBs by clearing HWO and incrementing dequeue + * pointer. + * + * Note that we have 2 possible types of transfers here: + * + * i) Linear buffer request + * ii) SG-list based request + * + * SG-list based requests will have r->num_pending_sgs + * set to a valid number (> 0). Linear requests, + * normally use a single TRB. + * + * For each of these two cases, if r->unaligned flag is + * set, one extra TRB has been used to align transfer + * size to wMaxPacketSize. + * + * All of these cases need to be taken into + * consideration so we don't mess up our TRB ring + * pointers. + */ + wait_event_lock_irq(dep->wait_end_transfer, + !(dep->flags & DWC3_EP_END_TRANSFER_PENDING), + dwc->lock); + + if (!r->trb) + goto out1; + + if (r->num_pending_sgs) { + struct dwc3_trb *trb; + int i = 0; + + for (i = 0; i < r->num_pending_sgs; i++) { + trb = r->trb + i; + trb->ctrl &= ~DWC3_TRB_CTRL_HWO; + dwc3_ep_inc_deq(dep); + } + + if (r->unaligned) { + trb = r->trb + r->num_pending_sgs + 1; + trb->ctrl &= ~DWC3_TRB_CTRL_HWO; + dwc3_ep_inc_deq(dep); + } + } else { + struct dwc3_trb *trb = r->trb; + + trb->ctrl &= ~DWC3_TRB_CTRL_HWO; + dwc3_ep_inc_deq(dep); + + if (r->unaligned) { + trb = r->trb + 1; + trb->ctrl &= ~DWC3_TRB_CTRL_HWO; + dwc3_ep_inc_deq(dep); + } + } goto out1; } dev_err(dwc->dev, "request %p was not queued to %s\n", @@ -1352,6 +1414,7 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep, out1: /* giveback the request */ + dep->queued_requests--; dwc3_gadget_giveback(dep, req, -ECONNRESET); out0: -- 2.20.1