[RFC PATCH v2 0/6] ASoC: fsl: add memory to memory function for ASRC

[Shengjiu Wang]

This function is base on the accelerator implementation
for compress API:
https://patchwork.kernel.org/project/alsa-devel/patch/20240731083843.59911-1-perex@perex.cz/

Audio signal processing also has the requirement for memory to
memory similar as Video.

This asrc memory to memory (memory ->asrc->memory) case is a non
real time use case.

User fills the input buffer to the asrc module, after conversion, then asrc
sends back the output buffer to user. So it is not a traditional ALSA playback
and capture case.

Because we had implemented the "memory -> asrc ->i2s device-> codec"
use case in ALSA.  Now the "memory->asrc->memory" needs
to reuse the code in asrc driver, so the patch 1 and patch 2 is for refining
the code to make it can be shared by the "memory->asrc->memory"
driver.

Other change is to add memory to memory support for two kinds of i.MX ASRC
modules.

changes in v2:
- Remove the changes in compress API
- drop the SNDRV_COMPRESS_SRC_RATIO_MOD
- drop the SND_AUDIOCODEC_SRC and struct snd_dec_src
- define private metadata key value
  ASRC_OUTPUT_FORMAT/ASRC_OUTPUT_RATE/ASRC_RATIO_MOD

Shengjiu Wang (6):
  ALSA: compress: reserve space in snd_compr_metadata.key for private
    usage
  ASoC: fsl_asrc: define functions for memory to memory usage
  ASoC: fsl_easrc: define functions for memory to memory usage
  ASoC: fsl_asrc_m2m: Add memory to memory function
  ASoC: fsl_asrc: register m2m platform device
  ASoC: fsl_easrc: register m2m platform device

 include/uapi/sound/compress_offload.h |   2 +-
 sound/soc/fsl/Kconfig                 |   1 +
 sound/soc/fsl/Makefile                |   2 +-
 sound/soc/fsl/fsl_asrc.c              | 176 +++++-
 sound/soc/fsl/fsl_asrc.h              |   2 +
 sound/soc/fsl/fsl_asrc_common.h       |  68 +++
 sound/soc/fsl/fsl_asrc_m2m.c          | 791 ++++++++++++++++++++++++++
 sound/soc/fsl/fsl_easrc.c             | 259 ++++++++-
 sound/soc/fsl/fsl_easrc.h             |   4 +
 9 files changed, 1297 insertions(+), 8 deletions(-)
 create mode 100644 sound/soc/fsl/fsl_asrc_m2m.c

-- 
2.34.1