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usb: dwc3: gadget: Improve TRB ZLP setup

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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: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
This commit is contained in:
Thinh Nguyen 2020-09-24 01:21:36 -07:00 committed by Felipe Balbi
parent 2b80357b77
commit a2841f41d0
1 changed files with 18 additions and 32 deletions
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50
drivers/usb/dwc3/gadget.c
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@ -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 */
dwc3_prepare_one_trb(dep, req, trb_length,
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,
@ -1151,13 +1152,9 @@ 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,
false, 1, true);
dwc3_prepare_one_trb(dep, req,
req->direction ? 0 : maxp,
false, 1, true);
} else {
dwc3_prepare_one_trb(dep, req, trb_length,
chain, i, false);
@ -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 */
dwc3_prepare_one_trb(dep, req, length, true, 0, false);
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;
}