usb: dwc3: gadget: Handle stream transfers
Overview of stream transfer requirement: * A transfer will have a set of TRBs of the same stream ID. * A transfer is started with a stream ID in START_TRANSFER command. * A new stream will only start when the previous completes. Overview of stream events: * A "prime" from host indicates that its endpoints are active (buffers prepared and ready to receive/transmit data). The controller automatically initiates stream if it sees this. * A "NoStream" rejection event indicates that the host isn't ready. Host will put the endpoint back to idle state. Device may need to reinitiate the stream to start transfer again. * A Stream Found event means host accepted device initiated stream. Nothing needs to be done from driver. To initiate a stream, the driver will issue START_TRANSFER command with a stream ID. To reinitiate the stream, the driver must issue END_TRANSFER and restart the transfer with START_TRANSFER command with the same stream ID. This implementation handles device-initated streams (e.g. UASP driver). It also handles some hosts' quirky behavior where they only prime each endpoint once. Signed-off-by:Thinh Nguyen <thinhn@synopsys.com> Signed-off-by:
Felipe Balbi <balbi@kernel.org>
parent
aefe3d23
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