Commit a2841f41 authored by Thinh Nguyen's avatar Thinh Nguyen Committed by Felipe Balbi
Browse files

usb: dwc3: gadget: Improve TRB ZLP setup 



For OUT requests that requires extra TRBs for ZLP. We don't need to
prepare the 0-length TRB and simply prepare the MPS size TRB. This
reduces 1 TRB needed to prepare for ZLP.

Signed-off-by: default avatarThinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: default avatarFelipe Balbi <balbi@kernel.org>
parent 2b80357b

drivers/usb/dwc3/gadget.c

+18 −32
Original line number Diff line number Diff line
@@ -1132,11 +1132,12 @@ static void dwc3_prepare_one_trb_sg(struct dwc3_ep *dep, 
			chain = false;



		if (rem && usb_endpoint_dir_out(dep->endpoint.desc) && !chain) {

			req->needs_extra_trb = true;



			/* prepare normal TRB */

			if (req->request.length) {

				req->needs_extra_trb = true;

				dwc3_prepare_one_trb(dep, req, trb_length,

					true, i, false);

			}



			/* Now prepare one extra TRB to align transfer size */

			dwc3_prepare_one_trb(dep, req, maxp - rem,
@@ -1151,12 +1152,8 @@ static void dwc3_prepare_one_trb_sg(struct dwc3_ep *dep, 
					true, i, false);



			/* Prepare one extra TRB to handle ZLP */

			dwc3_prepare_one_trb(dep, req, 0,

					!req->direction, 1, true);



			/* Prepare one more TRB to handle MPS alignment */

			if (!req->direction)

				dwc3_prepare_one_trb(dep, req, maxp,

			dwc3_prepare_one_trb(dep, req,

					req->direction ? 0 : maxp,

					false, 1, true);

		} else {

			dwc3_prepare_one_trb(dep, req, trb_length,
@@ -1198,10 +1195,11 @@ static void dwc3_prepare_one_trb_linear(struct dwc3_ep *dep, 
	unsigned int rem = length % maxp;



	if ((!length || rem) && usb_endpoint_dir_out(dep->endpoint.desc)) {

		req->needs_extra_trb = true;



		/* prepare normal TRB */

		if (req->request.length) {

			req->needs_extra_trb = true;

			dwc3_prepare_one_trb(dep, req, length, true, 0, false);

		}



		/* Now prepare one extra TRB to align transfer size */

		dwc3_prepare_one_trb(dep, req, maxp - rem, false, 1, true);
@@ -1214,11 +1212,8 @@ static void dwc3_prepare_one_trb_linear(struct dwc3_ep *dep, 
		dwc3_prepare_one_trb(dep, req, length, true, 0, false);



		/* Prepare one extra TRB to handle ZLP */

		dwc3_prepare_one_trb(dep, req, 0, !req->direction, 1, true);



		/* Prepare one more TRB to handle MPS alignment for OUT */

		if (!req->direction)

			dwc3_prepare_one_trb(dep, req, maxp, false, 1, true);

		dwc3_prepare_one_trb(dep, req, req->direction ? 0 : maxp,

				false, 1, true);

	} else {

		dwc3_prepare_one_trb(dep, req, length, false, 0, false);

	}
@@ -2621,12 +2616,12 @@ static int dwc3_gadget_ep_reclaim_completed_trb(struct dwc3_ep *dep, 
	}



	/*

	 * If we're dealing with unaligned size OUT transfer, we will be left

	 * with one TRB pending in the ring. We need to manually clear HWO bit

	 * from that TRB.

	 * We use bounce buffer for requests that needs extra TRB or OUT ZLP. If

	 * this TRB points to the bounce buffer address, it's a MPS alignment

	 * TRB. Don't add it to req->remaining calculation.

	 */



	if (req->needs_extra_trb && !(trb->ctrl & DWC3_TRB_CTRL_CHN)) {

	if (trb->bpl == lower_32_bits(dep->dwc->bounce_addr) &&

	    trb->bph == upper_32_bits(dep->dwc->bounce_addr)) {

		trb->ctrl &= ~DWC3_TRB_CTRL_HWO;

		return 1;

	}
@@ -2707,17 +2702,8 @@ static int dwc3_gadget_ep_cleanup_completed_request(struct dwc3_ep *dep, 
		goto out;



	if (req->needs_extra_trb) {

		unsigned int maxp = usb_endpoint_maxp(dep->endpoint.desc);



		ret = dwc3_gadget_ep_reclaim_trb_linear(dep, req, event,

				status);



		/* Reclaim MPS padding TRB for ZLP */

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

		    !usb_endpoint_xfer_isoc(dep->endpoint.desc) &&

		    (IS_ALIGNED(req->request.length, maxp)))

			ret = dwc3_gadget_ep_reclaim_trb_linear(dep, req, event, status);



		req->needs_extra_trb = false;

	}

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