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

From: Hans Verkuil
Date: Fri Oct 27 2023 - 07:18:26 EST

Hi Shengjiu,

Is there a reason why this series is still marked RFC?

Just wondering about that.

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%)
>