Commit d72ecc08 authored Sep 29, 2020 by Thinh Nguyen Committed by Felipe Balbi Oct 02, 2020

usb: dwc3: gadget: Allow restarting a transfer



It's possible that there's no new TRBs prepared when kicking a transfer.
This happens when we need to stop and restart a transfer such as in the
case of reinitiating a stream or retrying isoc transfer. For streams,
sometime host may reject a stream and the device may need to reinitiate
that stream by stopping and restarting a transfer. In this case, all the
TRBs may have already been prepared. Allow the function
__dwc3_gadget_kick_transfer() to go through even though there's no new
TRB.

Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

parent a73abc28

drivers/usb/dwc3/gadget.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -1326,8 +1326,13 @@ static int __dwc3_gadget_kick_transfer(struct dwc3_ep *dep)
		int ret;
		u32 cmd;

		/*
		* Note that it's normal to have no new TRBs prepared (i.e. ret == 0).
		* This happens when we need to stop and restart a transfer such as in
		* the case of reinitiating a stream or retrying an isoc transfer.
		*/
		ret = dwc3_prepare_trbs(dep);
		if (ret <= 0)
		if (ret < 0)
		return ret;

		starting = !(dep->flags & DWC3_EP_TRANSFER_STARTED);

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