ASoC: qcom: qdsp6: Introduce USB AFE port to q6dsp

The QC ADSP is able to support USB playback endpoints, so that the main
application processor can be placed into lower CPU power modes.  This adds
the required AFE port configurations and port start command to start an
audio session.

Specifically, the QC ADSP can support all potential endpoints that are
exposed by the audio data interface.  This includes isochronous data
endpoints, in either synchronous mode or asynchronous mode. In the latter
case both implicit or explicit feedback endpoints are supported.  The size
of audio samples sent per USB frame (microframe) will be adjusted based on
information received on the feedback endpoint.

Some pre-requisites are needed before issuing the AFE port start command,
such as setting the USB AFE dev_token.  This carries information about the
available USB SND cards and PCM devices that have been discovered on the
USB bus.  The dev_token field is used by the audio DSP to notify the USB
offload driver of which card and PCM index to enable playback on.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409194804.3773260-23-quic_wcheng@quicinc.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>