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Commit e5b36ae2 authored by Felipe Balbi's avatar Felipe Balbi
Browse files

usb: dwc3: gadget: fix for short pkts during chained xfers 



DWC3 has one interesting peculiarity with chained
transfers. If we setup N chained transfers and we
get a short packet before processing all N TRBs,
DWC3 will (conditionally) issue a XferComplete or
XferInProgress event and retire all TRBs from the
one which got a short packet to the last without
clearing their HWO bits.

This means SW must clear HWO bit manually, which
this patch is doing.

Cc: <stable@vger.kernel.org>
Cc: Brian E Rogers <brian.e.rogers@intel.com>
Signed-off-by: default avatarFelipe Balbi <felipe.balbi@linux.intel.com>
parent c7de5734

drivers/usb/dwc3/gadget.c

+20 −3
Original line number Diff line number Diff line
@@ -1955,7 +1955,8 @@ static void dwc3_gadget_free_endpoints(struct dwc3 *dwc) 


static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,

		struct dwc3_request *req, struct dwc3_trb *trb,

		const struct dwc3_event_depevt *event, int status)

		const struct dwc3_event_depevt *event, int status,

		int chain)

{

	unsigned int		count;

	unsigned int		s_pkt = 0;
@@ -1964,6 +1965,19 @@ static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep, 
	dep->queued_requests--;

	trace_dwc3_complete_trb(dep, trb);



	/*

	 * If we're in the middle of series of chained TRBs and we

	 * receive a short transfer along the way, DWC3 will skip

	 * through all TRBs including the last TRB in the chain (the

	 * where CHN bit is zero. DWC3 will also avoid clearing HWO

	 * bit and SW has to do it manually.

	 *

	 * We're going to do that here to avoid problems of HW trying

	 * to use bogus TRBs for transfers.

	 */

	if (chain && (trb->ctrl & DWC3_TRB_CTRL_HWO))

		trb->ctrl &= ~DWC3_TRB_CTRL_HWO;



	if ((trb->ctrl & DWC3_TRB_CTRL_HWO) && status != -ESHUTDOWN)

		/*

		 * We continue despite the error. There is not much we
@@ -1975,6 +1989,7 @@ static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep, 
		 */

		dev_err(dwc->dev, "%s's TRB (%p) still owned by HW\n",

				dep->name, trb);



	count = trb->size & DWC3_TRB_SIZE_MASK;



	if (dep->direction) {
@@ -2036,10 +2051,13 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep, 
	int			ret;



	do {

		int chain;



		req = next_request(&dep->started_list);

		if (WARN_ON_ONCE(!req))

			return 1;



		chain = req->request.num_mapped_sgs > 0;

		i = 0;

		do {

			slot = req->first_trb_index + i;
@@ -2049,9 +2067,8 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep, 
			trb = &dep->trb_pool[slot];

			count += trb->size & DWC3_TRB_SIZE_MASK;





			ret = __dwc3_cleanup_done_trbs(dwc, dep, req, trb,

					event, status);

					event, status, chain);

			if (ret)

				break;

		} while (++i < req->request.num_mapped_sgs);