Re: [PATCH v10 00/14] Add audio support in v4l2 framework

[Hans Verkuil]

On 21/11/2023 08:37, Shengjiu Wang wrote:
> 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.
> 
> It is a specific use case,  there is no reference in current kernel.
> v4l2 memory to memory is the closed implementation,  v4l2 current
> support video, image, radio, tuner, touch devices, so it is not
> complicated to add support for this specific audio 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 first 3 patches is for refining
> the code to make it can be shared by the "memory->asrc->memory"
> driver.
> 
> The main change is in the v4l2 side, A /dev/vl4-audioX will be created,
> user applications only use the ioctl of v4l2 framework.
> 
> Other change is to add memory to memory support for two kinds of i.MX ASRC
> module.
> 
> changes in v10
> - remove FIXED_POINT type
> - change code base on media: v4l2-ctrls: add support for fraction_bits
> - fix issue reported by kernel test robot
> - remove module_alias

Note that I still need a patch for vivid adding a fixed point test control.

I think I want two controls: one INTEGER Q16 and one INTEGER64 Q63 (a nice
corner case).

Regards,

	Hans

> 
> changes in v9:
> - add MEDIA_ENT_F_PROC_AUDIO_RESAMPLER.
> - add MEDIA_INTF_T_V4L_AUDIO
> - add media controller support
> - refine the vim2m-audio to support 8k<->16k conversion.
> 
> changes in v8:
> - refine V4L2_CAP_AUDIO_M2M to be 0x00000008
> - update doc for FIXED_POINT
> - address comments for imx-asrc
> 
> changes in v7:
> - add acked-by from Mark
> - separate commit for fixed point, m2m audio class, audio rate controls
> - use INTEGER_MENU for rate,  FIXED_POINT for rate offset
> - remove used fmts
> - address other comments for Hans
> 
> changes in v6:
> - use m2m_prepare/m2m_unprepare/m2m_start/m2m_stop to replace
>   m2m_start_part_one/m2m_stop_part_one, m2m_start_part_two/m2m_stop_part_two.
> - change V4L2_CTRL_TYPE_ASRC_RATE to V4L2_CTRL_TYPE_FIXED_POINT
> - fix warning by kernel test rebot
> - remove some unused format V4L2_AUDIO_FMT_XX
> - Get SNDRV_PCM_FORMAT from V4L2_AUDIO_FMT in driver.
> - rename audm2m to viaudm2m.
> 
> changes in v5:
> - remove V4L2_AUDIO_FMT_LPCM
> - define audio pixel format like V4L2_AUDIO_FMT_S8...
> - remove rate and format in struct v4l2_audio_format.
> - Add V4L2_CID_ASRC_SOURCE_RATE and V4L2_CID_ASRC_DEST_RATE controls
> - updata document accordingly.
> 
> changes in v4:
> - update document style
> - separate V4L2_AUDIO_FMT_LPCM and V4L2_CAP_AUDIO_M2M in separate commit
> 
> changes in v3:
> - Modify documents for adding audio m2m support
> - Add audio virtual m2m driver
> - Defined V4L2_AUDIO_FMT_LPCM format type for audio.
> - Defined V4L2_CAP_AUDIO_M2M capability type for audio m2m case.
> - with modification in v4l-utils, pass v4l2-compliance test.
> 
> changes in v2:
> - decouple the implementation in v4l2 and ALSA
> - implement the memory to memory driver as a platfrom driver
>   and move it to driver/media
> - move fsl_asrc_common.h to include/sound folder
> 
> Shengjiu Wang (14):
>   ASoC: fsl_asrc: define functions for memory to memory usage
>   ASoC: fsl_easrc: define functions for memory to memory usage
>   ASoC: fsl_asrc: move fsl_asrc_common.h to include/sound
>   ASoC: fsl_asrc: register m2m platform device
>   ASoC: fsl_easrc: register m2m platform device
>   media: uapi: Add V4L2_CAP_AUDIO_M2M capability flag
>   media: v4l2: Add audio capture and output support
>   media: uapi: Define audio sample format fourcc type
>   media: uapi: Add V4L2_CTRL_CLASS_M2M_AUDIO
>   media: uapi: Add audio rate controls support
>   media: uapi: Declare interface types for Audio
>   media: uapi: Add an entity type for audio resampler
>   media: imx-asrc: Add memory to memory driver
>   media: vim2m-audio: add virtual driver for audio memory to memory
> 
>  .../media/mediactl/media-types.rst            |   11 +
>  .../userspace-api/media/v4l/buffer.rst        |    6 +
>  .../userspace-api/media/v4l/common.rst        |    1 +
>  .../media/v4l/dev-audio-mem2mem.rst           |   71 +
>  .../userspace-api/media/v4l/devices.rst       |    1 +
>  .../media/v4l/ext-ctrls-audio-m2m.rst         |   41 +
>  .../userspace-api/media/v4l/pixfmt-audio.rst  |   87 ++
>  .../userspace-api/media/v4l/pixfmt.rst        |    1 +
>  .../media/v4l/vidioc-enum-fmt.rst             |    2 +
>  .../media/v4l/vidioc-g-ext-ctrls.rst          |    4 +
>  .../userspace-api/media/v4l/vidioc-g-fmt.rst  |    4 +
>  .../media/v4l/vidioc-querycap.rst             |    3 +
>  .../media/videodev2.h.rst.exceptions          |    3 +
>  .../media/common/videobuf2/videobuf2-v4l2.c   |    4 +
>  drivers/media/platform/nxp/Kconfig            |   13 +
>  drivers/media/platform/nxp/Makefile           |    1 +
>  drivers/media/platform/nxp/imx-asrc.c         | 1264 +++++++++++++++++
>  drivers/media/test-drivers/Kconfig            |   11 +
>  drivers/media/test-drivers/Makefile           |    1 +
>  drivers/media/test-drivers/vim2m-audio.c      |  799 +++++++++++
>  drivers/media/v4l2-core/v4l2-compat-ioctl32.c |    9 +
>  drivers/media/v4l2-core/v4l2-ctrls-defs.c     |   10 +
>  drivers/media/v4l2-core/v4l2-dev.c            |   21 +
>  drivers/media/v4l2-core/v4l2-ioctl.c          |   66 +
>  drivers/media/v4l2-core/v4l2-mem2mem.c        |   13 +-
>  include/media/v4l2-dev.h                      |    2 +
>  include/media/v4l2-ioctl.h                    |   34 +
>  .../fsl => include/sound}/fsl_asrc_common.h   |   60 +
>  include/uapi/linux/media.h                    |    2 +
>  include/uapi/linux/v4l2-controls.h            |    9 +
>  include/uapi/linux/videodev2.h                |   41 +
>  sound/soc/fsl/fsl_asrc.c                      |  144 ++
>  sound/soc/fsl/fsl_asrc.h                      |    4 +-
>  sound/soc/fsl/fsl_asrc_dma.c                  |    2 +-
>  sound/soc/fsl/fsl_easrc.c                     |  233 +++
>  sound/soc/fsl/fsl_easrc.h                     |    6 +-
>  36 files changed, 2977 insertions(+), 7 deletions(-)
>  create mode 100644 Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
>  create mode 100644 Documentation/userspace-api/media/v4l/ext-ctrls-audio-m2m.rst
>  create mode 100644 Documentation/userspace-api/media/v4l/pixfmt-audio.rst
>  create mode 100644 drivers/media/platform/nxp/imx-asrc.c
>  create mode 100644 drivers/media/test-drivers/vim2m-audio.c
>  rename {sound/soc/fsl => include/sound}/fsl_asrc_common.h (60%)
>