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Commit f849fcfc authored by Vamsi Krishna's avatar Vamsi Krishna
Browse files

dwc3: gadget: Check available trbs before processing req 



if number of trbs not sufficient while processing request with
scatter/gather buffers some buffers may be dropped. To avoid
dropping packets check for available trbs before processing
number of trbs.

Change-Id: Ia85e2b57d20117d2319923b59c78b69c26385e42
Signed-off-by: default avatarVamsi Krishna <vskrishn@codeaurora.org>
parent bdac9783

drivers/usb/dwc3/gadget.c

+59 −6
Original line number Diff line number Diff line
@@ -964,6 +964,11 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool starting) 
	u32			trbs_left;

	u32			max;

	unsigned int		last_one = 0;

	int			maxpkt_size;

	bool			isoc;



	maxpkt_size = usb_endpoint_maxp(dep->endpoint.desc);

	isoc = usb_endpoint_xfer_isoc(dep->endpoint.desc);



	BUILD_BUG_ON_NOT_POWER_OF_2(DWC3_TRB_NUM);
@@ -1006,17 +1011,31 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool starting) 
		}

	}



	/* The last TRB is a link TRB, not used for xfer */

	if ((trbs_left <= 1) && usb_endpoint_xfer_isoc(dep->endpoint.desc))

		return;



	list_for_each_entry_safe(req, n, &dep->request_list, list) {

		unsigned	length;

		dma_addr_t	dma;

		bool		last_req = list_is_last(&req->list,

							&dep->request_list);

		int		num_trbs_required = 0;



		last_one = false;



		/* The last TRB is a link TRB, not used for xfer */

		if (isoc)

			num_trbs_required++;



		if (req->request.num_mapped_sgs)

			num_trbs_required += req->request.num_mapped_sgs;

		else

			num_trbs_required++;



		if (req->request.zero && req->request.length &&

				(req->request.length % maxpkt_size == 0))

			num_trbs_required++;



		if (trbs_left < num_trbs_required)

			break;



		if (req->request.num_mapped_sgs > 0) {

			struct usb_request *request = &req->request;

			struct scatterlist *sg = request->sg;
@@ -1031,11 +1050,45 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool starting) 


				if (i == (request->num_mapped_sgs - 1) ||

						sg_is_last(s)) {

					if (last_req)

						last_one = true;

					unsigned temp = 0;

					unsigned len;

					struct dwc3_request *nreq = n;

					struct usb_request *ureq;

					bool mpkt = false;



					chain = false;

					if (last_req) {

						last_one = true;

						goto start_trb_queuing;

					}



					/*

					 * check if trbs sufficient for next

					 * request to set the last bit

					 */

					ureq = &nreq->request;

					len  = ureq->length;



					if (len % maxpkt_size == 0)

						mpkt = true;



					if (ureq->zero && len && mpkt)

						temp++;



					if (ureq->num_mapped_sgs)

						temp +=

						ureq->num_mapped_sgs;

					else

						temp++;



					if (isoc)

						temp++;



					if (trbs_left <= temp)

						last_one = true;

				}



start_trb_queuing:

				trbs_left--;

				if (!trbs_left)

					last_one = true;