[RFC PATCH v8 00/13] Add audio support in v4l2 framework

[Shengjiu Wang]

On Fri, Oct 27, 2023 at 7:18 PM Hans Verkuil <hverkuil at xs4all.nl> wrote:
>
> Hi Shengjiu,
>
> Is there a reason why this series is still marked RFC?
>
> Just wondering about that.

In the very beginning I started this series with RFC, So
I still use RFC now...

Best regards
Wang shengjiu
>
> Regards,
>
>         Hans
>
> On 27/10/2023 12:35, 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 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 (13):
> >   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 V4L2_CTRL_TYPE_FIXED_POINT
> >   media: uapi: Add audio rate controls support
> >   media: imx-asrc: Add memory to memory driver
> >   media: vim2m_audio: add virtual driver for audio memory to memory
> >
> >  .../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          |   17 +-
> >  .../userspace-api/media/v4l/vidioc-g-fmt.rst  |    4 +
> >  .../media/v4l/vidioc-querycap.rst             |    3 +
> >  .../media/v4l/vidioc-queryctrl.rst            |    9 +-
> >  .../media/videodev2.h.rst.exceptions          |    4 +
> >  .../media/common/videobuf2/videobuf2-v4l2.c   |    4 +
> >  drivers/media/platform/nxp/Kconfig            |   12 +
> >  drivers/media/platform/nxp/Makefile           |    1 +
> >  drivers/media/platform/nxp/imx-asrc.c         | 1186 +++++++++++++++++
> >  drivers/media/test-drivers/Kconfig            |    9 +
> >  drivers/media/test-drivers/Makefile           |    1 +
> >  drivers/media/test-drivers/vim2m_audio.c      |  680 ++++++++++
> >  drivers/media/v4l2-core/v4l2-ctrls-api.c      |    5 +-
> >  drivers/media/v4l2-core/v4l2-ctrls-core.c     |    2 +
> >  drivers/media/v4l2-core/v4l2-ctrls-defs.c     |   16 +
> >  drivers/media/v4l2-core/v4l2-dev.c            |   17 +
> >  drivers/media/v4l2-core/v4l2-ioctl.c          |   66 +
> >  include/media/v4l2-dev.h                      |    2 +
> >  include/media/v4l2-ioctl.h                    |   34 +
> >  .../fsl => include/sound}/fsl_asrc_common.h   |   60 +
> >  include/uapi/linux/v4l2-controls.h            |    9 +
> >  include/uapi/linux/videodev2.h                |   42 +
> >  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 +-
> >  35 files changed, 2771 insertions(+), 11 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%)
> >
>