diff options
| -rw-r--r-- | drivers/usb/dwc3/ep0.c | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c index 39abc589187a..69d5741a4db0 100644 --- a/drivers/usb/dwc3/ep0.c +++ b/drivers/usb/dwc3/ep0.c @@ -174,6 +174,49 @@ static int __dwc3_gadget_ep0_queue(struct dwc3_ep *dep, return 0; } + /* + * Unfortunately we have uncovered a limitation wrt the Data Phase. + * + * Section 9.4 says we can wait for the XferNotReady(DATA) event to + * come before issueing Start Transfer command, but if we do, we will + * miss situations where the host starts another SETUP phase instead of + * the DATA phase. Such cases happen at least on TD.7.6 of the Link + * Layer Compliance Suite. + * + * The problem surfaces due to the fact that in case of back-to-back + * SETUP packets there will be no XferNotReady(DATA) generated and we + * will be stuck waiting for XferNotReady(DATA) forever. + * + * By looking at tables 9-13 and 9-14 of the Databook, we can see that + * it tells us to start Data Phase right away. It also mentions that if + * we receive a SETUP phase instead of the DATA phase, core will issue + * XferComplete for the DATA phase, before actually initiating it in + * the wire, with the TRB's status set to "SETUP_PENDING". Such status + * can only be used to print some debugging logs, as the core expects + * us to go through to the STATUS phase and start a CONTROL_STATUS TRB, + * just so it completes right away, without transferring anything and, + * only then, we can go back to the SETUP phase. + * + * Because of this scenario, SNPS decided to change the programming + * model of control transfers and support on-demand transfers only for + * the STATUS phase. To fix the issue we have now, we will always wait + * for gadget driver to queue the DATA phase's struct usb_request, then + * start it right away. + * + * If we're actually in a 2-stage transfer, we will wait for + * XferNotReady(STATUS). + */ + if (dwc->three_stage_setup) { + unsigned direction; + + direction = dwc->ep0_expect_in; + dwc->ep0state = EP0_DATA_PHASE; + + __dwc3_ep0_do_control_data(dwc, dwc->eps[direction], req); + + dep->flags &= ~DWC3_EP0_DIR_IN; + } + return 0; } @@ -707,6 +750,7 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc, struct dwc3_trb *trb; struct dwc3_ep *ep0; u32 transferred; + u32 status; u32 length; u8 epnum; @@ -719,6 +763,17 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc, ur = &r->request; trb = dwc->ep0_trb; + + status = DWC3_TRB_SIZE_TRBSTS(trb->size); + if (status == DWC3_TRBSTS_SETUP_PENDING) { + dev_dbg(dwc->dev, "Setup Pending received\n"); + + if (r) + dwc3_gadget_giveback(ep0, r, -ECONNRESET); + + return; + } + length = trb->size & DWC3_TRB_SIZE_MASK; if (dwc->ep0_bounced) { @@ -755,8 +810,11 @@ static void dwc3_ep0_complete_status(struct dwc3 *dwc, { struct dwc3_request *r; struct dwc3_ep *dep; + struct dwc3_trb *trb; + u32 status; dep = dwc->eps[0]; + trb = dwc->ep0_trb; if (!list_empty(&dep->request_list)) { r = next_request(&dep->request_list); @@ -776,6 +834,10 @@ static void dwc3_ep0_complete_status(struct dwc3 *dwc, } } + status = DWC3_TRB_SIZE_TRBSTS(trb->size); + if (status == DWC3_TRBSTS_SETUP_PENDING) + dev_dbg(dwc->dev, "Setup Pending received\n"); + dwc->ep0state = EP0_SETUP_PHASE; dwc3_ep0_out_start(dwc); } |