[PATCH 0/2] Add raw OPUS codec support for compress offload

[Alexey Klimov <alexey.klimov@xxxxxxxxxx>]

This series adds support in kernel to recognise raw (or plain) OPUS
codec playback for compress offloading. At this point this series
doesn't deal with OPUS packets packed in any kind of containers (OGG or
others) and focuses on adding missing bits for pure OPUS packets.

The second patch adds its usage in Qualcomm Audio DSP code. To correctly
recognise raw OPUS packets by qdsp6, each packets needs to be prepended
with 4-bytes field that contains length of a raw OPUS packet.
It is expected to be useful for usecases when OPUS packets are streamed
over network and they are not encapsulated in a container. Userspace
application that will use the compress API has to manually add such
4-bytes long field to each OPUS packet.

This is tested on sm8750-mtp. It is expected that next hardware revisions
will also support raw OPUS codec offloading.

Dependencies are:
-- hardware with DSP that supports decoding OPUS packets (>=sm8750);
-- adsp fastrpc;
-- explicitly setting format in sm8750 soundcard driver;
-- running adsprpcd tool with support for Audio PD and DSP libraries
loading support (or its alternative);
-- tinycompress fcplay tool that will prepare raw opus packets and
do the required addition of length field;
-- mfc module in topology compress-playback path, that module is
expected to parse channel mapping and do the required things to
map streams/channels to physically-present output channels on backend.

The userspace tinycompress tool with support for raw OPUS compress
playback is located here:
https://github.com/laklimov/tinycompress_opus
branch: opus_v3_workinprogress

The userspace tool is not expected that it is ready and still needs
some work, for instance recognition that it runs on Qualcomm hardware.
More like working PoC.

Signed-off-by: Alexey Klimov <alexey.klimov@xxxxxxxxxx>
---
Changes since RFC (mostly as suggetsed by Srini):
- added struct snd_dec_opus_ch_map to struct snd_dec_opus;
- changed tags;
- reworked comments for struct snd_dec_opus;
In qcom audioreach patch:
- corrected how {stream_count,coupled_count} is ejected from mcfg->codec;
- stopped dealing with channel mapping parsing (this is internal struct for
  decoder on audio DSP side);
- used sizeof(*opus_cfg) for payload size;
Tinycompress/fcplay:
- small updates to match kernel structs.
- Link to RFC: https://lore.kernel.org/r/20250616-opus_codec_rfc_v1-v1-0-1f70b0a41a70@xxxxxxxxxx

---
Alexey Klimov (2):
      ALSA: compress: add raw opus codec define and opus decoder structs
      ASoC: qcom: qdsp6/audioreach: add support for offloading raw opus playback

 include/uapi/sound/compress_params.h | 43 +++++++++++++++++++++++++++++++++++-
 sound/soc/qcom/qdsp6/audioreach.c    | 27 ++++++++++++++++++++++
 sound/soc/qcom/qdsp6/audioreach.h    | 17 ++++++++++++++
 sound/soc/qcom/qdsp6/q6apm-dai.c     |  3 ++-
 sound/soc/qcom/qdsp6/q6apm.c         |  3 +++
 5 files changed, 91 insertions(+), 2 deletions(-)
---
base-commit: 886e5e7b0432360842303d587bb4a65d10741ae8
change-id: 20250616-opus_codec_rfc_v1-b60bd308893b

Best regards,
-- 
Alexey Klimov <alexey.klimov@xxxxxxxxxx>