[v12,07/15] media: v4l2: Add audio capture and output support

Commit Message

Shengjiu Wang Jan. 18, 2024, 12:32 p.m. UTC

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

This patch is to add this support in v4l2 framework, defined
new buffer type V4L2_BUF_TYPE_AUDIO_CAPTURE and
V4L2_BUF_TYPE_AUDIO_OUTPUT, defined new format v4l2_audio_format
for audio case usage.

The created audio device is named "/dev/v4l-audioX".

Signed-off-by: Shengjiu Wang <[e-mail]>
---
 .../userspace-api/media/v4l/buffer.rst        |  6 ++
 .../media/v4l/dev-audio-mem2mem.rst           | 71 +++++++++++++++++++
 .../userspace-api/media/v4l/devices.rst       |  1 +
 .../media/v4l/vidioc-enum-fmt.rst             |  2 +
 .../userspace-api/media/v4l/vidioc-g-fmt.rst  |  4 ++
 .../media/videodev2.h.rst.exceptions          |  2 +
 .../media/common/videobuf2/videobuf2-v4l2.c   |  4 ++
 drivers/media/v4l2-core/v4l2-compat-ioctl32.c |  9 +++
 drivers/media/v4l2-core/v4l2-dev.c            | 17 +++++
 drivers/media/v4l2-core/v4l2-ioctl.c          | 53 ++++++++++++++
 include/media/v4l2-dev.h                      |  2 +
 include/media/v4l2-ioctl.h                    | 34 +++++++++
 include/uapi/linux/videodev2.h                | 17 +++++
 13 files changed, 222 insertions(+)
 create mode 100644 Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst

Comments

Mauro Carvalho Chehab Feb. 17, 2024, 9:42 a.m. UTC | #1

Em Thu, 18 Jan 2024 20:32:00 +0800
Shengjiu Wang <[e-mail]> escreveu:

> Audio signal processing has the requirement for memory to
> memory similar as Video.
> 
> This patch is to add this support in v4l2 framework, defined
> new buffer type V4L2_BUF_TYPE_AUDIO_CAPTURE and
> V4L2_BUF_TYPE_AUDIO_OUTPUT, defined new format v4l2_audio_format
> for audio case usage.
> 
> The created audio device is named "/dev/v4l-audioX".
> 
> Signed-off-by: Shengjiu Wang <[e-mail]>
> ---
>  .../userspace-api/media/v4l/buffer.rst        |  6 ++
>  .../media/v4l/dev-audio-mem2mem.rst           | 71 +++++++++++++++++++
>  .../userspace-api/media/v4l/devices.rst       |  1 +
>  .../media/v4l/vidioc-enum-fmt.rst             |  2 +
>  .../userspace-api/media/v4l/vidioc-g-fmt.rst  |  4 ++
>  .../media/videodev2.h.rst.exceptions          |  2 +
>  .../media/common/videobuf2/videobuf2-v4l2.c   |  4 ++
>  drivers/media/v4l2-core/v4l2-compat-ioctl32.c |  9 +++
>  drivers/media/v4l2-core/v4l2-dev.c            | 17 +++++
>  drivers/media/v4l2-core/v4l2-ioctl.c          | 53 ++++++++++++++
>  include/media/v4l2-dev.h                      |  2 +
>  include/media/v4l2-ioctl.h                    | 34 +++++++++
>  include/uapi/linux/videodev2.h                | 17 +++++
>  13 files changed, 222 insertions(+)
>  create mode 100644 Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
> 
> diff --git a/Documentation/userspace-api/media/v4l/buffer.rst b/Documentation/userspace-api/media/v4l/buffer.rst
> index 52bbee81c080..a3754ca6f0d6 100644
> --- a/Documentation/userspace-api/media/v4l/buffer.rst
> +++ b/Documentation/userspace-api/media/v4l/buffer.rst
> @@ -438,6 +438,12 @@ enum v4l2_buf_type
>      * - ``V4L2_BUF_TYPE_META_OUTPUT``
>        - 14

>        - Buffer for metadata output, see :ref:`metadata`.
> +    * - ``V4L2_BUF_TYPE_AUDIO_CAPTURE``
> +      - 15
> +      - Buffer for audio capture, see :ref:`audio`.
> +    * - ``V4L2_BUF_TYPE_AUDIO_OUTPUT``
> +      - 16

Hmm... alsa APi define input/output as:
	enum {
	        SNDRV_PCM_STREAM_PLAYBACK = 0,
	        SNDRV_PCM_STREAM_CAPTURE,
	        SNDRV_PCM_STREAM_LAST = SNDRV_PCM_STREAM_CAPTURE,
	};


I would use a namespace as close as possible to the
ALSA API. Also, we're not talking about V4L2, but, instead
audio. so, not sure if I like the prefix to start with
V4L2_. Maybe ALSA_?

So, a better namespace would be:

	${prefix}_BUF_TYPE_PCM_STREAM_PLAYBACK
and
	${prefix}_BUF_TYPE_PCM_STREAM_CAPTURE

> +      - Buffer for audio output, see :ref:`audio`.
>  
>  
>  .. _buffer-flags:
> diff --git a/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst b/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
> new file mode 100644
> index 000000000000..68faecfe3a02
> --- /dev/null
> +++ b/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
> @@ -0,0 +1,71 @@
> +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
> +
> +.. _audiomem2mem:
> +
> +********************************
> +Audio Memory-To-Memory Interface
> +********************************
> +
> +An audio memory-to-memory device can compress, decompress, transform, or
> +otherwise convert audio data from one format into another format, in memory.
> +Such memory-to-memory devices set the ``V4L2_CAP_AUDIO_M2M`` capability.
> +Examples of memory-to-memory devices are audio codecs, audio preprocessing,
> +audio postprocessing.
> +
> +A memory-to-memory audio node supports both output (sending audio frames from
> +memory to the hardware) and capture (receiving the processed audio frames
> +from the hardware into memory) stream I/O. An application will have to
> +setup the stream I/O for both sides and finally call
> +:ref:`VIDIOC_STREAMON <VIDIOC_STREAMON>` for both capture and output to
> +start the hardware.
> +
> +Memory-to-memory devices function as a shared resource: you can
> +open the audio node multiple times, each application setting up their
> +own properties that are local to the file handle, and each can use
> +it independently from the others. The driver will arbitrate access to
> +the hardware and reprogram it whenever another file handler gets access.
> +
> +Audio memory-to-memory devices are accessed through character device
> +special files named ``/dev/v4l-audio``
> +
> +Querying Capabilities
> +=====================
> +
> +Device nodes supporting the audio memory-to-memory interface set the
> +``V4L2_CAP_AUDIO_M2M`` flag in the ``device_caps`` field of the
> +:c:type:`v4l2_capability` structure returned by the :c:func:`VIDIOC_QUERYCAP`
> +ioctl.
> +
> +Data Format Negotiation
> +=======================
> +
> +The audio device uses the :ref:`format` ioctls to select the capture format.
> +The audio buffer content format is bound to that selected format. In addition
> +to the basic :ref:`format` ioctls, the :c:func:`VIDIOC_ENUM_FMT` ioctl must be
> +supported as well.
> +
> +To use the :ref:`format` ioctls applications set the ``type`` field of the
> +:c:type:`v4l2_format` structure to ``V4L2_BUF_TYPE_AUDIO_CAPTURE`` or to
> +``V4L2_BUF_TYPE_AUDIO_OUTPUT``. Both drivers and applications must set the
> +remainder of the :c:type:`v4l2_format` structure to 0.
> +
> +.. c:type:: v4l2_audio_format
> +
> +.. tabularcolumns:: |p{1.4cm}|p{2.4cm}|p{13.5cm}|
> +
> +.. flat-table:: struct v4l2_audio_format
> +    :header-rows:  0
> +    :stub-columns: 0
> +    :widths:       1 1 2
> +
> +    * - __u32
> +      - ``pixelformat``
> +      - The sample format, set by the application. see :ref:`pixfmt-audio`

pixelformat doesn't make any sense for audio: there are no pixels on a
PCM stream. Please use call it, instead: `snd_pcm_format`, making it match
the values for snd_pcm_format_t.

Yet, I would keep defining it as u32 (or u64?) instead of using a
typedef int field there (snd_pcm_format_t), as the size of integer
is different on 32 and 64 bit kernels.


> +    * - __u32
> +      - ``channels``
> +      - The channel number, set by the application. channel number range is
> +        [1, 32].

Why not start on zero?

> +    * - __u32
> +      - ``buffersize``
> +      - Maximum buffer size in bytes required for data. The value is set by the
> +        driver.
> diff --git a/Documentation/userspace-api/media/v4l/devices.rst b/Documentation/userspace-api/media/v4l/devices.rst
> index 8bfbad65a9d4..758bd90f1c26 100644
> --- a/Documentation/userspace-api/media/v4l/devices.rst
> +++ b/Documentation/userspace-api/media/v4l/devices.rst
> @@ -24,3 +24,4 @@ Interfaces
>      dev-event
>      dev-subdev
>      dev-meta
> +    dev-audio-mem2mem
> diff --git a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
> index 000c154b0f98..42deb07f4ff4 100644
> --- a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
> +++ b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
> @@ -96,6 +96,8 @@ the ``mbus_code`` field is handled differently:
>  	``V4L2_BUF_TYPE_VIDEO_OVERLAY``,
>  	``V4L2_BUF_TYPE_SDR_CAPTURE``,
>  	``V4L2_BUF_TYPE_SDR_OUTPUT``,
> +	``V4L2_BUF_TYPE_AUDIO_CAPTURE``,
> +	``V4L2_BUF_TYPE_AUDIO_OUTPUT``,
>  	``V4L2_BUF_TYPE_META_CAPTURE`` and
>  	``V4L2_BUF_TYPE_META_OUTPUT``.
>  	See :c:type:`v4l2_buf_type`.
> diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-fmt.rst b/Documentation/userspace-api/media/v4l/vidioc-g-fmt.rst
> index 675c385e5aca..528fd9df41aa 100644
> --- a/Documentation/userspace-api/media/v4l/vidioc-g-fmt.rst
> +++ b/Documentation/userspace-api/media/v4l/vidioc-g-fmt.rst
> @@ -130,6 +130,10 @@ The format as returned by :ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>` must be identical
>        - ``meta``
>        - Definition of a metadata format, see :ref:`meta-formats`, used by
>  	metadata capture devices.
> +    * - struct :c:type:`v4l2_audio_format`
> +      - ``audio``
> +      - Definition of a audio data format, see :ref:`audiomem2mem`, used by
> +        audio memory-to-memory devices
>      * - __u8
>        - ``raw_data``\ [200]
>        - Place holder for future extensions.
> diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> index da6d0b8e4c2c..e61152bb80d1 100644
> --- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> +++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> @@ -29,6 +29,8 @@ replace symbol V4L2_FIELD_SEQ_TB :c:type:`v4l2_field`
>  replace symbol V4L2_FIELD_TOP :c:type:`v4l2_field`
>  
>  # Documented enum v4l2_buf_type
> +replace symbol V4L2_BUF_TYPE_AUDIO_CAPTURE :c:type:`v4l2_buf_type`
> +replace symbol V4L2_BUF_TYPE_AUDIO_OUTPUT :c:type:`v4l2_buf_type`
>  replace symbol V4L2_BUF_TYPE_META_CAPTURE :c:type:`v4l2_buf_type`
>  replace symbol V4L2_BUF_TYPE_META_OUTPUT :c:type:`v4l2_buf_type`
>  replace symbol V4L2_BUF_TYPE_SDR_CAPTURE :c:type:`v4l2_buf_type`
> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> index 54d572c3b515..16ab204d15b0 100644
> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> @@ -791,6 +791,10 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
>  	case V4L2_BUF_TYPE_META_OUTPUT:
>  		requested_sizes[0] = f->fmt.meta.buffersize;
>  		break;
> +	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
> +	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
> +		requested_sizes[0] = f->fmt.audio.buffersize;
> +		break;
>  	default:
>  		return -EINVAL;
>  	}
> diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> index 8c07400bd280..5e94db8dfdae 100644
> --- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> +++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> @@ -101,6 +101,7 @@ struct v4l2_format32 {
>  		struct v4l2_sliced_vbi_format	sliced;
>  		struct v4l2_sdr_format	sdr;
>  		struct v4l2_meta_format	meta;
> +		struct v4l2_audio_format	audio;
>  		__u8	raw_data[200];        /* user-defined */
>  	} fmt;
>  };
> @@ -166,6 +167,10 @@ static int get_v4l2_format32(struct v4l2_format *p64,
>  	case V4L2_BUF_TYPE_META_OUTPUT:
>  		return copy_from_user(&p64->fmt.meta, &p32->fmt.meta,
>  				      sizeof(p64->fmt.meta)) ? -EFAULT : 0;
> +	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
> +	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
> +		return copy_from_user(&p64->fmt.audio, &p32->fmt.audio,
> +				      sizeof(p64->fmt.audio)) ? -EFAULT : 0;
>  	default:
>  		return -EINVAL;
>  	}
> @@ -216,6 +221,10 @@ static int put_v4l2_format32(struct v4l2_format *p64,
>  	case V4L2_BUF_TYPE_META_OUTPUT:
>  		return copy_to_user(&p32->fmt.meta, &p64->fmt.meta,
>  				    sizeof(p64->fmt.meta)) ? -EFAULT : 0;
> +	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
> +	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
> +		return copy_to_user(&p32->fmt.audio, &p64->fmt.audio,
> +				    sizeof(p64->fmt.audio)) ? -EFAULT : 0;
>  	default:
>  		return -EINVAL;
>  	}
> diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
> index d13954bd31fd..bac008fcedc6 100644
> --- a/drivers/media/v4l2-core/v4l2-dev.c
> +++ b/drivers/media/v4l2-core/v4l2-dev.c
> @@ -553,6 +553,7 @@ static void determine_valid_ioctls(struct video_device *vdev)
>  	bool is_tch = vdev->vfl_type == VFL_TYPE_TOUCH;
>  	bool is_meta = vdev->vfl_type == VFL_TYPE_VIDEO &&
>  		       (vdev->device_caps & meta_caps);
> +	bool is_audio = vdev->vfl_type == VFL_TYPE_AUDIO;
>  	bool is_rx = vdev->vfl_dir != VFL_DIR_TX;
>  	bool is_tx = vdev->vfl_dir != VFL_DIR_RX;
>  	bool is_io_mc = vdev->device_caps & V4L2_CAP_IO_MC;
> @@ -666,6 +667,19 @@ static void determine_valid_ioctls(struct video_device *vdev)
>  		SET_VALID_IOCTL(ops, VIDIOC_S_FMT, vidioc_s_fmt_meta_out);
>  		SET_VALID_IOCTL(ops, VIDIOC_TRY_FMT, vidioc_try_fmt_meta_out);
>  	}
> +	if (is_audio && is_rx) {
> +		/* audio capture specific ioctls */
> +		SET_VALID_IOCTL(ops, VIDIOC_ENUM_FMT, vidioc_enum_fmt_audio_cap);
> +		SET_VALID_IOCTL(ops, VIDIOC_G_FMT, vidioc_g_fmt_audio_cap);
> +		SET_VALID_IOCTL(ops, VIDIOC_S_FMT, vidioc_s_fmt_audio_cap);
> +		SET_VALID_IOCTL(ops, VIDIOC_TRY_FMT, vidioc_try_fmt_audio_cap);
> +	} else if (is_audio && is_tx) {
> +		/* audio output specific ioctls */
> +		SET_VALID_IOCTL(ops, VIDIOC_ENUM_FMT, vidioc_enum_fmt_audio_out);
> +		SET_VALID_IOCTL(ops, VIDIOC_G_FMT, vidioc_g_fmt_audio_out);
> +		SET_VALID_IOCTL(ops, VIDIOC_S_FMT, vidioc_s_fmt_audio_out);
> +		SET_VALID_IOCTL(ops, VIDIOC_TRY_FMT, vidioc_try_fmt_audio_out);
> +	}
>  	if (is_vbi) {
>  		/* vbi specific ioctls */
>  		if ((is_rx && (ops->vidioc_g_fmt_vbi_cap ||
> @@ -929,6 +943,9 @@ int __video_register_device(struct video_device *vdev,
>  	case VFL_TYPE_TOUCH:
>  		name_base = "v4l-touch";
>  		break;
> +	case VFL_TYPE_AUDIO:
> +		name_base = "v4l-audio";
> +		break;
>  	default:
>  		pr_err("%s called with unknown type: %d\n",
>  		       __func__, type);
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index 33076af4dfdb..e7be7c2f302d 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -188,6 +188,8 @@ const char *v4l2_type_names[] = {
>  	[V4L2_BUF_TYPE_SDR_OUTPUT]         = "sdr-out",
>  	[V4L2_BUF_TYPE_META_CAPTURE]       = "meta-cap",
>  	[V4L2_BUF_TYPE_META_OUTPUT]	   = "meta-out",
> +	[V4L2_BUF_TYPE_AUDIO_CAPTURE]      = "audio-cap",
> +	[V4L2_BUF_TYPE_AUDIO_OUTPUT]	   = "audio-out",
>  };
>  EXPORT_SYMBOL(v4l2_type_names);
>  
> @@ -276,6 +278,7 @@ static void v4l_print_format(const void *arg, bool write_only)
>  	const struct v4l2_sliced_vbi_format *sliced;
>  	const struct v4l2_window *win;
>  	const struct v4l2_meta_format *meta;
> +	const struct v4l2_audio_format *audio;
>  	u32 pixelformat;
>  	u32 planes;
>  	unsigned i;
> @@ -346,6 +349,13 @@ static void v4l_print_format(const void *arg, bool write_only)
>  		pr_cont(", dataformat=%p4cc, buffersize=%u\n",
>  			&pixelformat, meta->buffersize);
>  		break;
> +	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
> +	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
> +		audio = &p->fmt.audio;
> +		pixelformat = audio->audioformat;
> +		pr_cont(", format=%p4cc, channels=%u, buffersize=%u\n",
> +			&pixelformat, audio->channels, audio->buffersize);
> +		break;
>  	}
>  }
>  
> @@ -927,6 +937,7 @@ static int check_fmt(struct file *file, enum v4l2_buf_type type)
>  	bool is_tch = vfd->vfl_type == VFL_TYPE_TOUCH;
>  	bool is_meta = vfd->vfl_type == VFL_TYPE_VIDEO &&
>  		       (vfd->device_caps & meta_caps);
> +	bool is_audio = vfd->vfl_type == VFL_TYPE_AUDIO;
>  	bool is_rx = vfd->vfl_dir != VFL_DIR_TX;
>  	bool is_tx = vfd->vfl_dir != VFL_DIR_RX;
>  
> @@ -992,6 +1003,14 @@ static int check_fmt(struct file *file, enum v4l2_buf_type type)
>  		if (is_meta && is_tx && ops->vidioc_g_fmt_meta_out)
>  			return 0;
>  		break;
> +	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
> +		if (is_audio && is_rx && ops->vidioc_g_fmt_audio_cap)
> +			return 0;
> +		break;
> +	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
> +		if (is_audio && is_tx && ops->vidioc_g_fmt_audio_out)
> +			return 0;
> +		break;
>  	default:
>  		break;
>  	}
> @@ -1597,6 +1616,16 @@ static int v4l_enum_fmt(const struct v4l2_ioctl_ops *ops,
>  			break;
>  		ret = ops->vidioc_enum_fmt_meta_out(file, fh, arg);
>  		break;
> +	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
> +		if (unlikely(!ops->vidioc_enum_fmt_audio_cap))
> +			break;
> +		ret = ops->vidioc_enum_fmt_audio_cap(file, fh, arg);
> +		break;
> +	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
> +		if (unlikely(!ops->vidioc_enum_fmt_audio_out))
> +			break;
> +		ret = ops->vidioc_enum_fmt_audio_out(file, fh, arg);
> +		break;
>  	}
>  	if (ret == 0)
>  		v4l_fill_fmtdesc(p);
> @@ -1673,6 +1702,10 @@ static int v4l_g_fmt(const struct v4l2_ioctl_ops *ops,
>  		return ops->vidioc_g_fmt_meta_cap(file, fh, arg);
>  	case V4L2_BUF_TYPE_META_OUTPUT:
>  		return ops->vidioc_g_fmt_meta_out(file, fh, arg);
> +	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
> +		return ops->vidioc_g_fmt_audio_cap(file, fh, arg);
> +	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
> +		return ops->vidioc_g_fmt_audio_out(file, fh, arg);
>  	}
>  	return -EINVAL;
>  }
> @@ -1784,6 +1817,16 @@ static int v4l_s_fmt(const struct v4l2_ioctl_ops *ops,
>  			break;
>  		memset_after(p, 0, fmt.meta);
>  		return ops->vidioc_s_fmt_meta_out(file, fh, arg);
> +	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
> +		if (unlikely(!ops->vidioc_s_fmt_audio_cap))
> +			break;
> +		memset_after(p, 0, fmt.audio);
> +		return ops->vidioc_s_fmt_audio_cap(file, fh, arg);
> +	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
> +		if (unlikely(!ops->vidioc_s_fmt_audio_out))
> +			break;
> +		memset_after(p, 0, fmt.audio);
> +		return ops->vidioc_s_fmt_audio_out(file, fh, arg);
>  	}
>  	return -EINVAL;
>  }
> @@ -1892,6 +1935,16 @@ static int v4l_try_fmt(const struct v4l2_ioctl_ops *ops,
>  			break;
>  		memset_after(p, 0, fmt.meta);
>  		return ops->vidioc_try_fmt_meta_out(file, fh, arg);
> +	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
> +		if (unlikely(!ops->vidioc_try_fmt_audio_cap))
> +			break;
> +		memset_after(p, 0, fmt.audio);
> +		return ops->vidioc_try_fmt_audio_cap(file, fh, arg);
> +	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
> +		if (unlikely(!ops->vidioc_try_fmt_audio_out))
> +			break;
> +		memset_after(p, 0, fmt.audio);
> +		return ops->vidioc_try_fmt_audio_out(file, fh, arg);
>  	}
>  	return -EINVAL;
>  }
> diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h
> index d82dfdbf6e58..82b63f82d43f 100644
> --- a/include/media/v4l2-dev.h
> +++ b/include/media/v4l2-dev.h
> @@ -30,6 +30,7 @@
>   * @VFL_TYPE_SUBDEV:	for V4L2 subdevices
>   * @VFL_TYPE_SDR:	for Software Defined Radio tuners
>   * @VFL_TYPE_TOUCH:	for touch sensors
> + * @VFL_TYPE_AUDIO:	for audio memory-to-memory devices
>   * @VFL_TYPE_MAX:	number of VFL types, must always be last in the enum
>   */
>  enum vfl_devnode_type {
> @@ -39,6 +40,7 @@ enum vfl_devnode_type {
>  	VFL_TYPE_SUBDEV,
>  	VFL_TYPE_SDR,
>  	VFL_TYPE_TOUCH,
> +	VFL_TYPE_AUDIO,
>  	VFL_TYPE_MAX /* Shall be the last one */
>  };
>  
> diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
> index edb733f21604..f840cf740ce1 100644
> --- a/include/media/v4l2-ioctl.h
> +++ b/include/media/v4l2-ioctl.h
> @@ -45,6 +45,12 @@ struct v4l2_fh;
>   * @vidioc_enum_fmt_meta_out: pointer to the function that implements
>   *	:ref:`VIDIOC_ENUM_FMT <vidioc_enum_fmt>` ioctl logic
>   *	for metadata output
> + * @vidioc_enum_fmt_audio_cap: pointer to the function that implements
> + *	:ref:`VIDIOC_ENUM_FMT <vidioc_enum_fmt>` ioctl logic
> + *	for audio capture
> + * @vidioc_enum_fmt_audio_out: pointer to the function that implements
> + *	:ref:`VIDIOC_ENUM_FMT <vidioc_enum_fmt>` ioctl logic
> + *	for audio output
>   * @vidioc_g_fmt_vid_cap: pointer to the function that implements
>   *	:ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for video capture
>   *	in single plane mode
> @@ -79,6 +85,10 @@ struct v4l2_fh;
>   *	:ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for metadata capture
>   * @vidioc_g_fmt_meta_out: pointer to the function that implements
>   *	:ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for metadata output
> + * @vidioc_g_fmt_audio_cap: pointer to the function that implements
> + *	:ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for audio capture
> + * @vidioc_g_fmt_audio_out: pointer to the function that implements
> + *	:ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for audio output
>   * @vidioc_s_fmt_vid_cap: pointer to the function that implements
>   *	:ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for video capture
>   *	in single plane mode
> @@ -113,6 +123,10 @@ struct v4l2_fh;
>   *	:ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for metadata capture
>   * @vidioc_s_fmt_meta_out: pointer to the function that implements
>   *	:ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for metadata output
> + * @vidioc_s_fmt_audio_cap: pointer to the function that implements
> + *	:ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for audio capture
> + * @vidioc_s_fmt_audio_out: pointer to the function that implements
> + *	:ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for audio output
>   * @vidioc_try_fmt_vid_cap: pointer to the function that implements
>   *	:ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for video capture
>   *	in single plane mode
> @@ -149,6 +163,10 @@ struct v4l2_fh;
>   *	:ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for metadata capture
>   * @vidioc_try_fmt_meta_out: pointer to the function that implements
>   *	:ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for metadata output
> + * @vidioc_try_fmt_audio_cap: pointer to the function that implements
> + *	:ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for audio capture
> + * @vidioc_try_fmt_audio_out: pointer to the function that implements
> + *	:ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for audio output
>   * @vidioc_reqbufs: pointer to the function that implements
>   *	:ref:`VIDIOC_REQBUFS <vidioc_reqbufs>` ioctl
>   * @vidioc_querybuf: pointer to the function that implements
> @@ -315,6 +333,10 @@ struct v4l2_ioctl_ops {
>  					struct v4l2_fmtdesc *f);
>  	int (*vidioc_enum_fmt_meta_out)(struct file *file, void *fh,
>  					struct v4l2_fmtdesc *f);
> +	int (*vidioc_enum_fmt_audio_cap)(struct file *file, void *fh,
> +					 struct v4l2_fmtdesc *f);
> +	int (*vidioc_enum_fmt_audio_out)(struct file *file, void *fh,
> +					 struct v4l2_fmtdesc *f);
>  
>  	/* VIDIOC_G_FMT handlers */
>  	int (*vidioc_g_fmt_vid_cap)(struct file *file, void *fh,
> @@ -345,6 +367,10 @@ struct v4l2_ioctl_ops {
>  				     struct v4l2_format *f);
>  	int (*vidioc_g_fmt_meta_out)(struct file *file, void *fh,
>  				     struct v4l2_format *f);
> +	int (*vidioc_g_fmt_audio_cap)(struct file *file, void *fh,
> +				      struct v4l2_format *f);
> +	int (*vidioc_g_fmt_audio_out)(struct file *file, void *fh,
> +				      struct v4l2_format *f);
>  
>  	/* VIDIOC_S_FMT handlers */
>  	int (*vidioc_s_fmt_vid_cap)(struct file *file, void *fh,
> @@ -375,6 +401,10 @@ struct v4l2_ioctl_ops {
>  				     struct v4l2_format *f);
>  	int (*vidioc_s_fmt_meta_out)(struct file *file, void *fh,
>  				     struct v4l2_format *f);
> +	int (*vidioc_s_fmt_audio_cap)(struct file *file, void *fh,
> +				      struct v4l2_format *f);
> +	int (*vidioc_s_fmt_audio_out)(struct file *file, void *fh,
> +				      struct v4l2_format *f);
>  
>  	/* VIDIOC_TRY_FMT handlers */
>  	int (*vidioc_try_fmt_vid_cap)(struct file *file, void *fh,
> @@ -405,6 +435,10 @@ struct v4l2_ioctl_ops {
>  				       struct v4l2_format *f);
>  	int (*vidioc_try_fmt_meta_out)(struct file *file, void *fh,
>  				       struct v4l2_format *f);
> +	int (*vidioc_try_fmt_audio_cap)(struct file *file, void *fh,
> +					struct v4l2_format *f);
> +	int (*vidioc_try_fmt_audio_out)(struct file *file, void *fh,
> +					struct v4l2_format *f);
>  
>  	/* Buffer handlers */
>  	int (*vidioc_reqbufs)(struct file *file, void *fh,
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 6cd65969c2b5..57c82eb158f1 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -153,6 +153,8 @@ enum v4l2_buf_type {
>  	V4L2_BUF_TYPE_SDR_OUTPUT           = 12,
>  	V4L2_BUF_TYPE_META_CAPTURE         = 13,
>  	V4L2_BUF_TYPE_META_OUTPUT	   = 14,
> +	V4L2_BUF_TYPE_AUDIO_CAPTURE        = 15,
> +	V4L2_BUF_TYPE_AUDIO_OUTPUT         = 16,
>  	/* Deprecated, do not use */
>  	V4L2_BUF_TYPE_PRIVATE              = 0x80,
>  };
> @@ -169,6 +171,7 @@ enum v4l2_buf_type {
>  	 || (type) == V4L2_BUF_TYPE_VBI_OUTPUT			\
>  	 || (type) == V4L2_BUF_TYPE_SLICED_VBI_OUTPUT		\
>  	 || (type) == V4L2_BUF_TYPE_SDR_OUTPUT			\
> +	 || (type) == V4L2_BUF_TYPE_AUDIO_OUTPUT		\
>  	 || (type) == V4L2_BUF_TYPE_META_OUTPUT)
>  
>  #define V4L2_TYPE_IS_CAPTURE(type) (!V4L2_TYPE_IS_OUTPUT(type))
> @@ -2423,6 +2426,18 @@ struct v4l2_meta_format {
>  	__u32				buffersize;
>  } __attribute__ ((packed));
>  
> +/**
> + * struct v4l2_audio_format - audio data format definition
> + * @audioformat:	little endian four character code (fourcc)

Don't use fourcc here. Instead, use the types defined at snd_pcm_format_t.

> + * @channels:		channel numbers
> + * @buffersize:		maximum size in bytes required for data
> + */
> +struct v4l2_audio_format {
> +	__u32				audioformat;
> +	__u32				channels;
> +	__u32				buffersize;
> +} __attribute__ ((packed));
> +
>  /**
>   * struct v4l2_format - stream data format
>   * @type:	enum v4l2_buf_type; type of the data stream
> @@ -2431,6 +2446,7 @@ struct v4l2_meta_format {
>   * @win:	definition of an overlaid image
>   * @vbi:	raw VBI capture or output parameters
>   * @sliced:	sliced VBI capture or output parameters
> + * @audio:	definition of an audio format
>   * @raw_data:	placeholder for future extensions and custom formats
>   * @fmt:	union of @pix, @pix_mp, @win, @vbi, @sliced, @sdr, @meta
>   *		and @raw_data
> @@ -2445,6 +2461,7 @@ struct v4l2_format {
>  		struct v4l2_sliced_vbi_format	sliced;  /* V4L2_BUF_TYPE_SLICED_VBI_CAPTURE */
>  		struct v4l2_sdr_format		sdr;     /* V4L2_BUF_TYPE_SDR_CAPTURE */
>  		struct v4l2_meta_format		meta;    /* V4L2_BUF_TYPE_META_CAPTURE */
> +		struct v4l2_audio_format	audio;   /* V4L2_BUF_TYPE_AUDIO_CAPTURE */
>  		__u8	raw_data[200];                   /* user-defined */
>  	} fmt;
>  };



Thanks,
Mauro

Shengjiu Wang Feb. 19, 2024, 6:35 a.m. UTC | #2

Hi Mauro,  Hans

On Sat, Feb 17, 2024 at 5:42 PM Mauro Carvalho Chehab
<[e-mail]> wrote:
>
> Em Thu, 18 Jan 2024 20:32:00 +0800
> Shengjiu Wang <[e-mail]> escreveu:
>
> > Audio signal processing has the requirement for memory to
> > memory similar as Video.
> >
> > This patch is to add this support in v4l2 framework, defined
> > new buffer type V4L2_BUF_TYPE_AUDIO_CAPTURE and
> > V4L2_BUF_TYPE_AUDIO_OUTPUT, defined new format v4l2_audio_format
> > for audio case usage.
> >
> > The created audio device is named "/dev/v4l-audioX".
> >
> > Signed-off-by: Shengjiu Wang <[e-mail]>
> > ---
> >  .../userspace-api/media/v4l/buffer.rst        |  6 ++
> >  .../media/v4l/dev-audio-mem2mem.rst           | 71 +++++++++++++++++++
> >  .../userspace-api/media/v4l/devices.rst       |  1 +
> >  .../media/v4l/vidioc-enum-fmt.rst             |  2 +
> >  .../userspace-api/media/v4l/vidioc-g-fmt.rst  |  4 ++
> >  .../media/videodev2.h.rst.exceptions          |  2 +
> >  .../media/common/videobuf2/videobuf2-v4l2.c   |  4 ++
> >  drivers/media/v4l2-core/v4l2-compat-ioctl32.c |  9 +++
> >  drivers/media/v4l2-core/v4l2-dev.c            | 17 +++++
> >  drivers/media/v4l2-core/v4l2-ioctl.c          | 53 ++++++++++++++
> >  include/media/v4l2-dev.h                      |  2 +
> >  include/media/v4l2-ioctl.h                    | 34 +++++++++
> >  include/uapi/linux/videodev2.h                | 17 +++++
> >  13 files changed, 222 insertions(+)
> >  create mode 100644 Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
> >
> > diff --git a/Documentation/userspace-api/media/v4l/buffer.rst b/Documentation/userspace-api/media/v4l/buffer.rst
> > index 52bbee81c080..a3754ca6f0d6 100644
> > --- a/Documentation/userspace-api/media/v4l/buffer.rst
> > +++ b/Documentation/userspace-api/media/v4l/buffer.rst
> > @@ -438,6 +438,12 @@ enum v4l2_buf_type
> >      * - ``V4L2_BUF_TYPE_META_OUTPUT``
> >        - 14
>
> >        - Buffer for metadata output, see :ref:`metadata`.
> > +    * - ``V4L2_BUF_TYPE_AUDIO_CAPTURE``
> > +      - 15
> > +      - Buffer for audio capture, see :ref:`audio`.
> > +    * - ``V4L2_BUF_TYPE_AUDIO_OUTPUT``
> > +      - 16
>
> Hmm... alsa APi define input/output as:
>         enum {
>                 SNDRV_PCM_STREAM_PLAYBACK = 0,
>                 SNDRV_PCM_STREAM_CAPTURE,
>                 SNDRV_PCM_STREAM_LAST = SNDRV_PCM_STREAM_CAPTURE,
>         };
>
>
> I would use a namespace as close as possible to the
> ALSA API. Also, we're not talking about V4L2, but, instead
> audio. so, not sure if I like the prefix to start with
> V4L2_. Maybe ALSA_?
>
> So, a better namespace would be:
>
>         ${prefix}_BUF_TYPE_PCM_STREAM_PLAYBACK
> and
>         ${prefix}_BUF_TYPE_PCM_STREAM_CAPTURE
>

Ok,  So can I use the name below?
V4L2_BUF_TYPE_PCM_STREAM_PLAYBACK
V4L2_BUF_TYPE_PCM_STREAM_CAPTURE

> > +      - Buffer for audio output, see :ref:`audio`.
> >
> >
> >  .. _buffer-flags:
> > diff --git a/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst b/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
> > new file mode 100644
> > index 000000000000..68faecfe3a02
> > --- /dev/null
> > +++ b/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
> > @@ -0,0 +1,71 @@
> > +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
> > +
> > +.. _audiomem2mem:
> > +
> > +********************************
> > +Audio Memory-To-Memory Interface
> > +********************************
> > +
> > +An audio memory-to-memory device can compress, decompress, transform, or
> > +otherwise convert audio data from one format into another format, in memory.
> > +Such memory-to-memory devices set the ``V4L2_CAP_AUDIO_M2M`` capability.
> > +Examples of memory-to-memory devices are audio codecs, audio preprocessing,
> > +audio postprocessing.
> > +
> > +A memory-to-memory audio node supports both output (sending audio frames from
> > +memory to the hardware) and capture (receiving the processed audio frames
> > +from the hardware into memory) stream I/O. An application will have to
> > +setup the stream I/O for both sides and finally call
> > +:ref:`VIDIOC_STREAMON <VIDIOC_STREAMON>` for both capture and output to
> > +start the hardware.
> > +
> > +Memory-to-memory devices function as a shared resource: you can
> > +open the audio node multiple times, each application setting up their
> > +own properties that are local to the file handle, and each can use
> > +it independently from the others. The driver will arbitrate access to
> > +the hardware and reprogram it whenever another file handler gets access.
> > +
> > +Audio memory-to-memory devices are accessed through character device
> > +special files named ``/dev/v4l-audio``
> > +
> > +Querying Capabilities
> > +=====================
> > +
> > +Device nodes supporting the audio memory-to-memory interface set the
> > +``V4L2_CAP_AUDIO_M2M`` flag in the ``device_caps`` field of the
> > +:c:type:`v4l2_capability` structure returned by the :c:func:`VIDIOC_QUERYCAP`
> > +ioctl.
> > +
> > +Data Format Negotiation
> > +=======================
> > +
> > +The audio device uses the :ref:`format` ioctls to select the capture format.
> > +The audio buffer content format is bound to that selected format. In addition
> > +to the basic :ref:`format` ioctls, the :c:func:`VIDIOC_ENUM_FMT` ioctl must be
> > +supported as well.
> > +
> > +To use the :ref:`format` ioctls applications set the ``type`` field of the
> > +:c:type:`v4l2_format` structure to ``V4L2_BUF_TYPE_AUDIO_CAPTURE`` or to
> > +``V4L2_BUF_TYPE_AUDIO_OUTPUT``. Both drivers and applications must set the
> > +remainder of the :c:type:`v4l2_format` structure to 0.
> > +
> > +.. c:type:: v4l2_audio_format
> > +
> > +.. tabularcolumns:: |p{1.4cm}|p{2.4cm}|p{13.5cm}|
> > +
> > +.. flat-table:: struct v4l2_audio_format
> > +    :header-rows:  0
> > +    :stub-columns: 0
> > +    :widths:       1 1 2
> > +
> > +    * - __u32
> > +      - ``pixelformat``
> > +      - The sample format, set by the application. see :ref:`pixfmt-audio`
>
> pixelformat doesn't make any sense for audio: there are no pixels on a
> PCM stream. Please use call it, instead: `snd_pcm_format`, making it match
> the values for snd_pcm_format_t.
>
> Yet, I would keep defining it as u32 (or u64?) instead of using a
> typedef int field there (snd_pcm_format_t), as the size of integer
> is different on 32 and 64 bit kernels.
>
>
> > +    * - __u32
> > +      - ``channels``
> > +      - The channel number, set by the application. channel number range is
> > +        [1, 32].
>
> Why not start on zero?

channels in audio are at least 1.

>
> > +    * - __u32
> > +      - ``buffersize``
> > +      - Maximum buffer size in bytes required for data. The value is set by the
> > +        driver.
> > diff --git a/Documentation/userspace-api/media/v4l/devices.rst b/Documentation/userspace-api/media/v4l/devices.rst
> > index 8bfbad65a9d4..758bd90f1c26 100644
> > --- a/Documentation/userspace-api/media/v4l/devices.rst
> > +++ b/Documentation/userspace-api/media/v4l/devices.rst
> > @@ -24,3 +24,4 @@ Interfaces
> >      dev-event
> >      dev-subdev
> >      dev-meta
> > +    dev-audio-mem2mem
> > diff --git a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
> > index 000c154b0f98..42deb07f4ff4 100644
> > --- a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
> > +++ b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
> > @@ -96,6 +96,8 @@ the ``mbus_code`` field is handled differently:
> >       ``V4L2_BUF_TYPE_VIDEO_OVERLAY``,
> >       ``V4L2_BUF_TYPE_SDR_CAPTURE``,
> >       ``V4L2_BUF_TYPE_SDR_OUTPUT``,
> > +     ``V4L2_BUF_TYPE_AUDIO_CAPTURE``,
> > +     ``V4L2_BUF_TYPE_AUDIO_OUTPUT``,
> >       ``V4L2_BUF_TYPE_META_CAPTURE`` and
> >       ``V4L2_BUF_TYPE_META_OUTPUT``.
> >       See :c:type:`v4l2_buf_type`.
> > diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-fmt.rst b/Documentation/userspace-api/media/v4l/vidioc-g-fmt.rst
> > index 675c385e5aca..528fd9df41aa 100644
> > --- a/Documentation/userspace-api/media/v4l/vidioc-g-fmt.rst
> > +++ b/Documentation/userspace-api/media/v4l/vidioc-g-fmt.rst
> > @@ -130,6 +130,10 @@ The format as returned by :ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>` must be identical
> >        - ``meta``
> >        - Definition of a metadata format, see :ref:`meta-formats`, used by
> >       metadata capture devices.
> > +    * - struct :c:type:`v4l2_audio_format`
> > +      - ``audio``
> > +      - Definition of a audio data format, see :ref:`audiomem2mem`, used by
> > +        audio memory-to-memory devices
> >      * - __u8
> >        - ``raw_data``\ [200]
> >        - Place holder for future extensions.
> > diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> > index da6d0b8e4c2c..e61152bb80d1 100644
> > --- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> > +++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> > @@ -29,6 +29,8 @@ replace symbol V4L2_FIELD_SEQ_TB :c:type:`v4l2_field`
> >  replace symbol V4L2_FIELD_TOP :c:type:`v4l2_field`
> >
> >  # Documented enum v4l2_buf_type
> > +replace symbol V4L2_BUF_TYPE_AUDIO_CAPTURE :c:type:`v4l2_buf_type`
> > +replace symbol V4L2_BUF_TYPE_AUDIO_OUTPUT :c:type:`v4l2_buf_type`
> >  replace symbol V4L2_BUF_TYPE_META_CAPTURE :c:type:`v4l2_buf_type`
> >  replace symbol V4L2_BUF_TYPE_META_OUTPUT :c:type:`v4l2_buf_type`
> >  replace symbol V4L2_BUF_TYPE_SDR_CAPTURE :c:type:`v4l2_buf_type`
> > diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> > index 54d572c3b515..16ab204d15b0 100644
> > --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
> > +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> > @@ -791,6 +791,10 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
> >       case V4L2_BUF_TYPE_META_OUTPUT:
> >               requested_sizes[0] = f->fmt.meta.buffersize;
> >               break;
> > +     case V4L2_BUF_TYPE_AUDIO_CAPTURE:
> > +     case V4L2_BUF_TYPE_AUDIO_OUTPUT:
> > +             requested_sizes[0] = f->fmt.audio.buffersize;
> > +             break;
> >       default:
> >               return -EINVAL;
> >       }
> > diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> > index 8c07400bd280..5e94db8dfdae 100644
> > --- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> > +++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> > @@ -101,6 +101,7 @@ struct v4l2_format32 {
> >               struct v4l2_sliced_vbi_format   sliced;
> >               struct v4l2_sdr_format  sdr;
> >               struct v4l2_meta_format meta;
> > +             struct v4l2_audio_format        audio;
> >               __u8    raw_data[200];        /* user-defined */
> >       } fmt;
> >  };
> > @@ -166,6 +167,10 @@ static int get_v4l2_format32(struct v4l2_format *p64,
> >       case V4L2_BUF_TYPE_META_OUTPUT:
> >               return copy_from_user(&p64->fmt.meta, &p32->fmt.meta,
> >                                     sizeof(p64->fmt.meta)) ? -EFAULT : 0;
> > +     case V4L2_BUF_TYPE_AUDIO_CAPTURE:
> > +     case V4L2_BUF_TYPE_AUDIO_OUTPUT:
> > +             return copy_from_user(&p64->fmt.audio, &p32->fmt.audio,
> > +                                   sizeof(p64->fmt.audio)) ? -EFAULT : 0;
> >       default:
> >               return -EINVAL;
> >       }
> > @@ -216,6 +221,10 @@ static int put_v4l2_format32(struct v4l2_format *p64,
> >       case V4L2_BUF_TYPE_META_OUTPUT:
> >               return copy_to_user(&p32->fmt.meta, &p64->fmt.meta,
> >                                   sizeof(p64->fmt.meta)) ? -EFAULT : 0;
> > +     case V4L2_BUF_TYPE_AUDIO_CAPTURE:
> > +     case V4L2_BUF_TYPE_AUDIO_OUTPUT:
> > +             return copy_to_user(&p32->fmt.audio, &p64->fmt.audio,
> > +                                 sizeof(p64->fmt.audio)) ? -EFAULT : 0;
> >       default:
> >               return -EINVAL;
> >       }
> > diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
> > index d13954bd31fd..bac008fcedc6 100644
> > --- a/drivers/media/v4l2-core/v4l2-dev.c
> > +++ b/drivers/media/v4l2-core/v4l2-dev.c
> > @@ -553,6 +553,7 @@ static void determine_valid_ioctls(struct video_device *vdev)
> >       bool is_tch = vdev->vfl_type == VFL_TYPE_TOUCH;
> >       bool is_meta = vdev->vfl_type == VFL_TYPE_VIDEO &&
> >                      (vdev->device_caps & meta_caps);
> > +     bool is_audio = vdev->vfl_type == VFL_TYPE_AUDIO;
> >       bool is_rx = vdev->vfl_dir != VFL_DIR_TX;
> >       bool is_tx = vdev->vfl_dir != VFL_DIR_RX;
> >       bool is_io_mc = vdev->device_caps & V4L2_CAP_IO_MC;
> > @@ -666,6 +667,19 @@ static void determine_valid_ioctls(struct video_device *vdev)
> >               SET_VALID_IOCTL(ops, VIDIOC_S_FMT, vidioc_s_fmt_meta_out);
> >               SET_VALID_IOCTL(ops, VIDIOC_TRY_FMT, vidioc_try_fmt_meta_out);
> >       }
> > +     if (is_audio && is_rx) {
> > +             /* audio capture specific ioctls */
> > +             SET_VALID_IOCTL(ops, VIDIOC_ENUM_FMT, vidioc_enum_fmt_audio_cap);
> > +             SET_VALID_IOCTL(ops, VIDIOC_G_FMT, vidioc_g_fmt_audio_cap);
> > +             SET_VALID_IOCTL(ops, VIDIOC_S_FMT, vidioc_s_fmt_audio_cap);
> > +             SET_VALID_IOCTL(ops, VIDIOC_TRY_FMT, vidioc_try_fmt_audio_cap);
> > +     } else if (is_audio && is_tx) {
> > +             /* audio output specific ioctls */
> > +             SET_VALID_IOCTL(ops, VIDIOC_ENUM_FMT, vidioc_enum_fmt_audio_out);
> > +             SET_VALID_IOCTL(ops, VIDIOC_G_FMT, vidioc_g_fmt_audio_out);
> > +             SET_VALID_IOCTL(ops, VIDIOC_S_FMT, vidioc_s_fmt_audio_out);
> > +             SET_VALID_IOCTL(ops, VIDIOC_TRY_FMT, vidioc_try_fmt_audio_out);
> > +     }
> >       if (is_vbi) {
> >               /* vbi specific ioctls */
> >               if ((is_rx && (ops->vidioc_g_fmt_vbi_cap ||
> > @@ -929,6 +943,9 @@ int __video_register_device(struct video_device *vdev,
> >       case VFL_TYPE_TOUCH:
> >               name_base = "v4l-touch";
> >               break;
> > +     case VFL_TYPE_AUDIO:
> > +             name_base = "v4l-audio";
> > +             break;
> >       default:
> >               pr_err("%s called with unknown type: %d\n",
> >                      __func__, type);
> > diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> > index 33076af4dfdb..e7be7c2f302d 100644
> > --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> > +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> > @@ -188,6 +188,8 @@ const char *v4l2_type_names[] = {
> >       [V4L2_BUF_TYPE_SDR_OUTPUT]         = "sdr-out",
> >       [V4L2_BUF_TYPE_META_CAPTURE]       = "meta-cap",
> >       [V4L2_BUF_TYPE_META_OUTPUT]        = "meta-out",
> > +     [V4L2_BUF_TYPE_AUDIO_CAPTURE]      = "audio-cap",
> > +     [V4L2_BUF_TYPE_AUDIO_OUTPUT]       = "audio-out",
> >  };
> >  EXPORT_SYMBOL(v4l2_type_names);
> >
> > @@ -276,6 +278,7 @@ static void v4l_print_format(const void *arg, bool write_only)
> >       const struct v4l2_sliced_vbi_format *sliced;
> >       const struct v4l2_window *win;
> >       const struct v4l2_meta_format *meta;
> > +     const struct v4l2_audio_format *audio;
> >       u32 pixelformat;
> >       u32 planes;
> >       unsigned i;
> > @@ -346,6 +349,13 @@ static void v4l_print_format(const void *arg, bool write_only)
> >               pr_cont(", dataformat=%p4cc, buffersize=%u\n",
> >                       &pixelformat, meta->buffersize);
> >               break;
> > +     case V4L2_BUF_TYPE_AUDIO_CAPTURE:
> > +     case V4L2_BUF_TYPE_AUDIO_OUTPUT:
> > +             audio = &p->fmt.audio;
> > +             pixelformat = audio->audioformat;
> > +             pr_cont(", format=%p4cc, channels=%u, buffersize=%u\n",
> > +                     &pixelformat, audio->channels, audio->buffersize);
> > +             break;
> >       }
> >  }
> >
> > @@ -927,6 +937,7 @@ static int check_fmt(struct file *file, enum v4l2_buf_type type)
> >       bool is_tch = vfd->vfl_type == VFL_TYPE_TOUCH;
> >       bool is_meta = vfd->vfl_type == VFL_TYPE_VIDEO &&
> >                      (vfd->device_caps & meta_caps);
> > +     bool is_audio = vfd->vfl_type == VFL_TYPE_AUDIO;
> >       bool is_rx = vfd->vfl_dir != VFL_DIR_TX;
> >       bool is_tx = vfd->vfl_dir != VFL_DIR_RX;
> >
> > @@ -992,6 +1003,14 @@ static int check_fmt(struct file *file, enum v4l2_buf_type type)
> >               if (is_meta && is_tx && ops->vidioc_g_fmt_meta_out)
> >                       return 0;
> >               break;
> > +     case V4L2_BUF_TYPE_AUDIO_CAPTURE:
> > +             if (is_audio && is_rx && ops->vidioc_g_fmt_audio_cap)
> > +                     return 0;
> > +             break;
> > +     case V4L2_BUF_TYPE_AUDIO_OUTPUT:
> > +             if (is_audio && is_tx && ops->vidioc_g_fmt_audio_out)
> > +                     return 0;
> > +             break;
> >       default:
> >               break;
> >       }
> > @@ -1597,6 +1616,16 @@ static int v4l_enum_fmt(const struct v4l2_ioctl_ops *ops,
> >                       break;
> >               ret = ops->vidioc_enum_fmt_meta_out(file, fh, arg);
> >               break;
> > +     case V4L2_BUF_TYPE_AUDIO_CAPTURE:
> > +             if (unlikely(!ops->vidioc_enum_fmt_audio_cap))
> > +                     break;
> > +             ret = ops->vidioc_enum_fmt_audio_cap(file, fh, arg);
> > +             break;
> > +     case V4L2_BUF_TYPE_AUDIO_OUTPUT:
> > +             if (unlikely(!ops->vidioc_enum_fmt_audio_out))
> > +                     break;
> > +             ret = ops->vidioc_enum_fmt_audio_out(file, fh, arg);
> > +             break;
> >       }
> >       if (ret == 0)
> >               v4l_fill_fmtdesc(p);
> > @@ -1673,6 +1702,10 @@ static int v4l_g_fmt(const struct v4l2_ioctl_ops *ops,
> >               return ops->vidioc_g_fmt_meta_cap(file, fh, arg);
> >       case V4L2_BUF_TYPE_META_OUTPUT:
> >               return ops->vidioc_g_fmt_meta_out(file, fh, arg);
> > +     case V4L2_BUF_TYPE_AUDIO_CAPTURE:
> > +             return ops->vidioc_g_fmt_audio_cap(file, fh, arg);
> > +     case V4L2_BUF_TYPE_AUDIO_OUTPUT:
> > +             return ops->vidioc_g_fmt_audio_out(file, fh, arg);
> >       }
> >       return -EINVAL;
> >  }
> > @@ -1784,6 +1817,16 @@ static int v4l_s_fmt(const struct v4l2_ioctl_ops *ops,
> >                       break;
> >               memset_after(p, 0, fmt.meta);
> >               return ops->vidioc_s_fmt_meta_out(file, fh, arg);
> > +     case V4L2_BUF_TYPE_AUDIO_CAPTURE:
> > +             if (unlikely(!ops->vidioc_s_fmt_audio_cap))
> > +                     break;
> > +             memset_after(p, 0, fmt.audio);
> > +             return ops->vidioc_s_fmt_audio_cap(file, fh, arg);
> > +     case V4L2_BUF_TYPE_AUDIO_OUTPUT:
> > +             if (unlikely(!ops->vidioc_s_fmt_audio_out))
> > +                     break;
> > +             memset_after(p, 0, fmt.audio);
> > +             return ops->vidioc_s_fmt_audio_out(file, fh, arg);
> >       }
> >       return -EINVAL;
> >  }
> > @@ -1892,6 +1935,16 @@ static int v4l_try_fmt(const struct v4l2_ioctl_ops *ops,
> >                       break;
> >               memset_after(p, 0, fmt.meta);
> >               return ops->vidioc_try_fmt_meta_out(file, fh, arg);
> > +     case V4L2_BUF_TYPE_AUDIO_CAPTURE:
> > +             if (unlikely(!ops->vidioc_try_fmt_audio_cap))
> > +                     break;
> > +             memset_after(p, 0, fmt.audio);
> > +             return ops->vidioc_try_fmt_audio_cap(file, fh, arg);
> > +     case V4L2_BUF_TYPE_AUDIO_OUTPUT:
> > +             if (unlikely(!ops->vidioc_try_fmt_audio_out))
> > +                     break;
> > +             memset_after(p, 0, fmt.audio);
> > +             return ops->vidioc_try_fmt_audio_out(file, fh, arg);
> >       }
> >       return -EINVAL;
> >  }
> > diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h
> > index d82dfdbf6e58..82b63f82d43f 100644
> > --- a/include/media/v4l2-dev.h
> > +++ b/include/media/v4l2-dev.h
> > @@ -30,6 +30,7 @@
> >   * @VFL_TYPE_SUBDEV: for V4L2 subdevices
> >   * @VFL_TYPE_SDR:    for Software Defined Radio tuners
> >   * @VFL_TYPE_TOUCH:  for touch sensors
> > + * @VFL_TYPE_AUDIO:  for audio memory-to-memory devices
> >   * @VFL_TYPE_MAX:    number of VFL types, must always be last in the enum
> >   */
> >  enum vfl_devnode_type {
> > @@ -39,6 +40,7 @@ enum vfl_devnode_type {
> >       VFL_TYPE_SUBDEV,
> >       VFL_TYPE_SDR,
> >       VFL_TYPE_TOUCH,
> > +     VFL_TYPE_AUDIO,
> >       VFL_TYPE_MAX /* Shall be the last one */
> >  };
> >
> > diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
> > index edb733f21604..f840cf740ce1 100644
> > --- a/include/media/v4l2-ioctl.h
> > +++ b/include/media/v4l2-ioctl.h
> > @@ -45,6 +45,12 @@ struct v4l2_fh;
> >   * @vidioc_enum_fmt_meta_out: pointer to the function that implements
> >   *   :ref:`VIDIOC_ENUM_FMT <vidioc_enum_fmt>` ioctl logic
> >   *   for metadata output
> > + * @vidioc_enum_fmt_audio_cap: pointer to the function that implements
> > + *   :ref:`VIDIOC_ENUM_FMT <vidioc_enum_fmt>` ioctl logic
> > + *   for audio capture
> > + * @vidioc_enum_fmt_audio_out: pointer to the function that implements
> > + *   :ref:`VIDIOC_ENUM_FMT <vidioc_enum_fmt>` ioctl logic
> > + *   for audio output
> >   * @vidioc_g_fmt_vid_cap: pointer to the function that implements
> >   *   :ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for video capture
> >   *   in single plane mode
> > @@ -79,6 +85,10 @@ struct v4l2_fh;
> >   *   :ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for metadata capture
> >   * @vidioc_g_fmt_meta_out: pointer to the function that implements
> >   *   :ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for metadata output
> > + * @vidioc_g_fmt_audio_cap: pointer to the function that implements
> > + *   :ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for audio capture
> > + * @vidioc_g_fmt_audio_out: pointer to the function that implements
> > + *   :ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for audio output
> >   * @vidioc_s_fmt_vid_cap: pointer to the function that implements
> >   *   :ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for video capture
> >   *   in single plane mode
> > @@ -113,6 +123,10 @@ struct v4l2_fh;
> >   *   :ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for metadata capture
> >   * @vidioc_s_fmt_meta_out: pointer to the function that implements
> >   *   :ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for metadata output
> > + * @vidioc_s_fmt_audio_cap: pointer to the function that implements
> > + *   :ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for audio capture
> > + * @vidioc_s_fmt_audio_out: pointer to the function that implements
> > + *   :ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for audio output
> >   * @vidioc_try_fmt_vid_cap: pointer to the function that implements
> >   *   :ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for video capture
> >   *   in single plane mode
> > @@ -149,6 +163,10 @@ struct v4l2_fh;
> >   *   :ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for metadata capture
> >   * @vidioc_try_fmt_meta_out: pointer to the function that implements
> >   *   :ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for metadata output
> > + * @vidioc_try_fmt_audio_cap: pointer to the function that implements
> > + *   :ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for audio capture
> > + * @vidioc_try_fmt_audio_out: pointer to the function that implements
> > + *   :ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for audio output
> >   * @vidioc_reqbufs: pointer to the function that implements
> >   *   :ref:`VIDIOC_REQBUFS <vidioc_reqbufs>` ioctl
> >   * @vidioc_querybuf: pointer to the function that implements
> > @@ -315,6 +333,10 @@ struct v4l2_ioctl_ops {
> >                                       struct v4l2_fmtdesc *f);
> >       int (*vidioc_enum_fmt_meta_out)(struct file *file, void *fh,
> >                                       struct v4l2_fmtdesc *f);
> > +     int (*vidioc_enum_fmt_audio_cap)(struct file *file, void *fh,
> > +                                      struct v4l2_fmtdesc *f);
> > +     int (*vidioc_enum_fmt_audio_out)(struct file *file, void *fh,
> > +                                      struct v4l2_fmtdesc *f);
> >
> >       /* VIDIOC_G_FMT handlers */
> >       int (*vidioc_g_fmt_vid_cap)(struct file *file, void *fh,
> > @@ -345,6 +367,10 @@ struct v4l2_ioctl_ops {
> >                                    struct v4l2_format *f);
> >       int (*vidioc_g_fmt_meta_out)(struct file *file, void *fh,
> >                                    struct v4l2_format *f);
> > +     int (*vidioc_g_fmt_audio_cap)(struct file *file, void *fh,
> > +                                   struct v4l2_format *f);
> > +     int (*vidioc_g_fmt_audio_out)(struct file *file, void *fh,
> > +                                   struct v4l2_format *f);
> >
> >       /* VIDIOC_S_FMT handlers */
> >       int (*vidioc_s_fmt_vid_cap)(struct file *file, void *fh,
> > @@ -375,6 +401,10 @@ struct v4l2_ioctl_ops {
> >                                    struct v4l2_format *f);
> >       int (*vidioc_s_fmt_meta_out)(struct file *file, void *fh,
> >                                    struct v4l2_format *f);
> > +     int (*vidioc_s_fmt_audio_cap)(struct file *file, void *fh,
> > +                                   struct v4l2_format *f);
> > +     int (*vidioc_s_fmt_audio_out)(struct file *file, void *fh,
> > +                                   struct v4l2_format *f);
> >
> >       /* VIDIOC_TRY_FMT handlers */
> >       int (*vidioc_try_fmt_vid_cap)(struct file *file, void *fh,
> > @@ -405,6 +435,10 @@ struct v4l2_ioctl_ops {
> >                                      struct v4l2_format *f);
> >       int (*vidioc_try_fmt_meta_out)(struct file *file, void *fh,
> >                                      struct v4l2_format *f);
> > +     int (*vidioc_try_fmt_audio_cap)(struct file *file, void *fh,
> > +                                     struct v4l2_format *f);
> > +     int (*vidioc_try_fmt_audio_out)(struct file *file, void *fh,
> > +                                     struct v4l2_format *f);
> >
> >       /* Buffer handlers */
> >       int (*vidioc_reqbufs)(struct file *file, void *fh,
> > diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> > index 6cd65969c2b5..57c82eb158f1 100644
> > --- a/include/uapi/linux/videodev2.h
> > +++ b/include/uapi/linux/videodev2.h
> > @@ -153,6 +153,8 @@ enum v4l2_buf_type {
> >       V4L2_BUF_TYPE_SDR_OUTPUT           = 12,
> >       V4L2_BUF_TYPE_META_CAPTURE         = 13,
> >       V4L2_BUF_TYPE_META_OUTPUT          = 14,
> > +     V4L2_BUF_TYPE_AUDIO_CAPTURE        = 15,
> > +     V4L2_BUF_TYPE_AUDIO_OUTPUT         = 16,
> >       /* Deprecated, do not use */
> >       V4L2_BUF_TYPE_PRIVATE              = 0x80,
> >  };
> > @@ -169,6 +171,7 @@ enum v4l2_buf_type {
> >        || (type) == V4L2_BUF_TYPE_VBI_OUTPUT                  \
> >        || (type) == V4L2_BUF_TYPE_SLICED_VBI_OUTPUT           \
> >        || (type) == V4L2_BUF_TYPE_SDR_OUTPUT                  \
> > +      || (type) == V4L2_BUF_TYPE_AUDIO_OUTPUT                \
> >        || (type) == V4L2_BUF_TYPE_META_OUTPUT)
> >
> >  #define V4L2_TYPE_IS_CAPTURE(type) (!V4L2_TYPE_IS_OUTPUT(type))
> > @@ -2423,6 +2426,18 @@ struct v4l2_meta_format {
> >       __u32                           buffersize;
> >  } __attribute__ ((packed));
> >
> > +/**
> > + * struct v4l2_audio_format - audio data format definition
> > + * @audioformat:     little endian four character code (fourcc)
>
> Don't use fourcc here. Instead, use the types defined at snd_pcm_format_t.

In the earlier version of this patch series,  fourcc is not used in this
struct v4l2_audio_format.

I use "__u32 audioformat", the value is from snd_pcm_format_t.
Using "__u32" is in order to avoid including the include/uapi/sound/asound.h
header.

And defined V4L2_AUDIO_FMT_LPCM for the v4l2_fmtdesc.pixelformat

#define V4L2_AUDIO_FMT_LPCM      v4l2_fourcc('L', 'P', 'C', 'M') /*
audio lpcm */

After discussing with Hans,  I use the current way for v4l audio.

Hans:
Not sure if you can accept going back to the previous solution?
You have already done similar changes in v4l-utils.

Best regards
Shengjiu Wang
>
> > + * @channels:                channel numbers
> > + * @buffersize:              maximum size in bytes required for data
> > + */
> > +struct v4l2_audio_format {
> > +     __u32                           audioformat;
> > +     __u32                           channels;
> > +     __u32                           buffersize;
> > +} __attribute__ ((packed));
> > +
> >  /**
> >   * struct v4l2_format - stream data format
> >   * @type:    enum v4l2_buf_type; type of the data stream
> > @@ -2431,6 +2446,7 @@ struct v4l2_meta_format {
> >   * @win:     definition of an overlaid image
> >   * @vbi:     raw VBI capture or output parameters
> >   * @sliced:  sliced VBI capture or output parameters
> > + * @audio:   definition of an audio format
> >   * @raw_data:        placeholder for future extensions and custom formats
> >   * @fmt:     union of @pix, @pix_mp, @win, @vbi, @sliced, @sdr, @meta
> >   *           and @raw_data
> > @@ -2445,6 +2461,7 @@ struct v4l2_format {
> >               struct v4l2_sliced_vbi_format   sliced;  /* V4L2_BUF_TYPE_SLICED_VBI_CAPTURE */
> >               struct v4l2_sdr_format          sdr;     /* V4L2_BUF_TYPE_SDR_CAPTURE */
> >               struct v4l2_meta_format         meta;    /* V4L2_BUF_TYPE_META_CAPTURE */
> > +             struct v4l2_audio_format        audio;   /* V4L2_BUF_TYPE_AUDIO_CAPTURE */
> >               __u8    raw_data[200];                   /* user-defined */
> >       } fmt;
> >  };
>
>
>
> Thanks,
> Mauro

Tomasz Figa Feb. 21, 2024, 4:30 a.m. UTC | #3

On Sat, Feb 17, 2024 at 6:42 PM Mauro Carvalho Chehab
<[e-mail]> wrote:
>
> Em Thu, 18 Jan 2024 20:32:00 +0800
> Shengjiu Wang <[e-mail]> escreveu:
>
> > Audio signal processing has the requirement for memory to
> > memory similar as Video.
> >
> > This patch is to add this support in v4l2 framework, defined
> > new buffer type V4L2_BUF_TYPE_AUDIO_CAPTURE and
> > V4L2_BUF_TYPE_AUDIO_OUTPUT, defined new format v4l2_audio_format
> > for audio case usage.
> >
> > The created audio device is named "/dev/v4l-audioX".
> >
> > Signed-off-by: Shengjiu Wang <[e-mail]>
> > ---
> >  .../userspace-api/media/v4l/buffer.rst        |  6 ++
> >  .../media/v4l/dev-audio-mem2mem.rst           | 71 +++++++++++++++++++
> >  .../userspace-api/media/v4l/devices.rst       |  1 +
> >  .../media/v4l/vidioc-enum-fmt.rst             |  2 +
> >  .../userspace-api/media/v4l/vidioc-g-fmt.rst  |  4 ++
> >  .../media/videodev2.h.rst.exceptions          |  2 +
> >  .../media/common/videobuf2/videobuf2-v4l2.c   |  4 ++
> >  drivers/media/v4l2-core/v4l2-compat-ioctl32.c |  9 +++
> >  drivers/media/v4l2-core/v4l2-dev.c            | 17 +++++
> >  drivers/media/v4l2-core/v4l2-ioctl.c          | 53 ++++++++++++++
> >  include/media/v4l2-dev.h                      |  2 +
> >  include/media/v4l2-ioctl.h                    | 34 +++++++++
> >  include/uapi/linux/videodev2.h                | 17 +++++
> >  13 files changed, 222 insertions(+)
> >  create mode 100644 Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
> >
> > diff --git a/Documentation/userspace-api/media/v4l/buffer.rst b/Documentation/userspace-api/media/v4l/buffer.rst
> > index 52bbee81c080..a3754ca6f0d6 100644
> > --- a/Documentation/userspace-api/media/v4l/buffer.rst
> > +++ b/Documentation/userspace-api/media/v4l/buffer.rst
> > @@ -438,6 +438,12 @@ enum v4l2_buf_type
> >      * - ``V4L2_BUF_TYPE_META_OUTPUT``
> >        - 14
>
> >        - Buffer for metadata output, see :ref:`metadata`.
> > +    * - ``V4L2_BUF_TYPE_AUDIO_CAPTURE``
> > +      - 15
> > +      - Buffer for audio capture, see :ref:`audio`.
> > +    * - ``V4L2_BUF_TYPE_AUDIO_OUTPUT``
> > +      - 16
>
> Hmm... alsa APi define input/output as:
>         enum {
>                 SNDRV_PCM_STREAM_PLAYBACK = 0,
>                 SNDRV_PCM_STREAM_CAPTURE,
>                 SNDRV_PCM_STREAM_LAST = SNDRV_PCM_STREAM_CAPTURE,
>         };
>
>
> I would use a namespace as close as possible to the
> ALSA API. Also, we're not talking about V4L2, but, instead
> audio. so, not sure if I like the prefix to start with
> V4L2_. Maybe ALSA_?
>
> So, a better namespace would be:
>
>         ${prefix}_BUF_TYPE_PCM_STREAM_PLAYBACK
> and
>         ${prefix}_BUF_TYPE_PCM_STREAM_CAPTURE
>

The API is still V4L2, and all the other non-video buf types also use
the V4L2_ prefix, so perhaps that's good here as well?

Whether AUDIO or PCM_STREAM makes more sense goes outside of my
expertise. Subjectively, a PCM stream sounds more specific than an
audio stream. Do those buf types also support non-PCM audio streams?

> > +      - Buffer for audio output, see :ref:`audio`.
> >
> >
> >  .. _buffer-flags:
> > diff --git a/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst b/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
> > new file mode 100644
> > index 000000000000..68faecfe3a02
> > --- /dev/null
> > +++ b/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
> > @@ -0,0 +1,71 @@
> > +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
> > +
> > +.. _audiomem2mem:
> > +
> > +********************************
> > +Audio Memory-To-Memory Interface
> > +********************************
> > +
> > +An audio memory-to-memory device can compress, decompress, transform, or
> > +otherwise convert audio data from one format into another format, in memory.
> > +Such memory-to-memory devices set the ``V4L2_CAP_AUDIO_M2M`` capability.
> > +Examples of memory-to-memory devices are audio codecs, audio preprocessing,
> > +audio postprocessing.
> > +
> > +A memory-to-memory audio node supports both output (sending audio frames from
> > +memory to the hardware) and capture (receiving the processed audio frames
> > +from the hardware into memory) stream I/O. An application will have to
> > +setup the stream I/O for both sides and finally call
> > +:ref:`VIDIOC_STREAMON <VIDIOC_STREAMON>` for both capture and output to
> > +start the hardware.
> > +
> > +Memory-to-memory devices function as a shared resource: you can
> > +open the audio node multiple times, each application setting up their
> > +own properties that are local to the file handle, and each can use
> > +it independently from the others. The driver will arbitrate access to
> > +the hardware and reprogram it whenever another file handler gets access.
> > +
> > +Audio memory-to-memory devices are accessed through character device
> > +special files named ``/dev/v4l-audio``
> > +
> > +Querying Capabilities
> > +=====================
> > +
> > +Device nodes supporting the audio memory-to-memory interface set the
> > +``V4L2_CAP_AUDIO_M2M`` flag in the ``device_caps`` field of the
> > +:c:type:`v4l2_capability` structure returned by the :c:func:`VIDIOC_QUERYCAP`
> > +ioctl.
> > +
> > +Data Format Negotiation
> > +=======================
> > +
> > +The audio device uses the :ref:`format` ioctls to select the capture format.
> > +The audio buffer content format is bound to that selected format. In addition
> > +to the basic :ref:`format` ioctls, the :c:func:`VIDIOC_ENUM_FMT` ioctl must be
> > +supported as well.
> > +
> > +To use the :ref:`format` ioctls applications set the ``type`` field of the
> > +:c:type:`v4l2_format` structure to ``V4L2_BUF_TYPE_AUDIO_CAPTURE`` or to
> > +``V4L2_BUF_TYPE_AUDIO_OUTPUT``. Both drivers and applications must set the
> > +remainder of the :c:type:`v4l2_format` structure to 0.
> > +
> > +.. c:type:: v4l2_audio_format
> > +
> > +.. tabularcolumns:: |p{1.4cm}|p{2.4cm}|p{13.5cm}|
> > +
> > +.. flat-table:: struct v4l2_audio_format
> > +    :header-rows:  0
> > +    :stub-columns: 0
> > +    :widths:       1 1 2
> > +
> > +    * - __u32
> > +      - ``pixelformat``
> > +      - The sample format, set by the application. see :ref:`pixfmt-audio`
>
> pixelformat doesn't make any sense for audio: there are no pixels on a
> PCM stream. Please use call it, instead: `snd_pcm_format`, making it match
> the values for snd_pcm_format_t.
>

+1

FWIW v4l2_meta_format uses the name "dataformat".

Actually, I just realized that the C code actually uses the name
"audioformat". Tbh., after reading the kerneldoc comment, my
subjective preference would be on "sample_format", since that's
exactly what it is.

> Yet, I would keep defining it as u32 (or u64?) instead of using a
> typedef int field there (snd_pcm_format_t), as the size of integer
> is different on 32 and 64 bit kernels.

+1

Best regards,
Tomasz

Tomasz Figa Feb. 21, 2024, 4:32 a.m. UTC | #4

On Thu, Jan 18, 2024 at 10:15 PM Shengjiu Wang <[e-mail]> wrote:
>
> Audio signal processing has the requirement for memory to
> memory similar as Video.
>
> This patch is to add this support in v4l2 framework, defined
> new buffer type V4L2_BUF_TYPE_AUDIO_CAPTURE and
> V4L2_BUF_TYPE_AUDIO_OUTPUT, defined new format v4l2_audio_format
> for audio case usage.
>
> The created audio device is named "/dev/v4l-audioX".
>
> Signed-off-by: Shengjiu Wang <[e-mail]>
> ---
>  .../userspace-api/media/v4l/buffer.rst        |  6 ++
>  .../media/v4l/dev-audio-mem2mem.rst           | 71 +++++++++++++++++++
>  .../userspace-api/media/v4l/devices.rst       |  1 +
>  .../media/v4l/vidioc-enum-fmt.rst             |  2 +
>  .../userspace-api/media/v4l/vidioc-g-fmt.rst  |  4 ++
>  .../media/videodev2.h.rst.exceptions          |  2 +
>  .../media/common/videobuf2/videobuf2-v4l2.c   |  4 ++
>  drivers/media/v4l2-core/v4l2-compat-ioctl32.c |  9 +++
>  drivers/media/v4l2-core/v4l2-dev.c            | 17 +++++
>  drivers/media/v4l2-core/v4l2-ioctl.c          | 53 ++++++++++++++
>  include/media/v4l2-dev.h                      |  2 +
>  include/media/v4l2-ioctl.h                    | 34 +++++++++
>  include/uapi/linux/videodev2.h                | 17 +++++
>  13 files changed, 222 insertions(+)
>  create mode 100644 Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst

For drivers/media/common/videobuf2:

Acked-by: Tomasz Figa <[e-mail]>

Best regards,
Tomasz

Shengjiu Wang Feb. 21, 2024, 10:11 a.m. UTC | #5

On Wed, Feb 21, 2024 at 12:30 PM Tomasz Figa <[e-mail]> wrote:
>
> On Sat, Feb 17, 2024 at 6:42 PM Mauro Carvalho Chehab
> <[e-mail]> wrote:
> >
> > Em Thu, 18 Jan 2024 20:32:00 +0800
> > Shengjiu Wang <[e-mail]> escreveu:
> >
> > > Audio signal processing has the requirement for memory to
> > > memory similar as Video.
> > >
> > > This patch is to add this support in v4l2 framework, defined
> > > new buffer type V4L2_BUF_TYPE_AUDIO_CAPTURE and
> > > V4L2_BUF_TYPE_AUDIO_OUTPUT, defined new format v4l2_audio_format
> > > for audio case usage.
> > >
> > > The created audio device is named "/dev/v4l-audioX".
> > >
> > > Signed-off-by: Shengjiu Wang <[e-mail]>
> > > ---
> > >  .../userspace-api/media/v4l/buffer.rst        |  6 ++
> > >  .../media/v4l/dev-audio-mem2mem.rst           | 71 +++++++++++++++++++
> > >  .../userspace-api/media/v4l/devices.rst       |  1 +
> > >  .../media/v4l/vidioc-enum-fmt.rst             |  2 +
> > >  .../userspace-api/media/v4l/vidioc-g-fmt.rst  |  4 ++
> > >  .../media/videodev2.h.rst.exceptions          |  2 +
> > >  .../media/common/videobuf2/videobuf2-v4l2.c   |  4 ++
> > >  drivers/media/v4l2-core/v4l2-compat-ioctl32.c |  9 +++
> > >  drivers/media/v4l2-core/v4l2-dev.c            | 17 +++++
> > >  drivers/media/v4l2-core/v4l2-ioctl.c          | 53 ++++++++++++++
> > >  include/media/v4l2-dev.h                      |  2 +
> > >  include/media/v4l2-ioctl.h                    | 34 +++++++++
> > >  include/uapi/linux/videodev2.h                | 17 +++++
> > >  13 files changed, 222 insertions(+)
> > >  create mode 100644 Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
> > >
> > > diff --git a/Documentation/userspace-api/media/v4l/buffer.rst b/Documentation/userspace-api/media/v4l/buffer.rst
> > > index 52bbee81c080..a3754ca6f0d6 100644
> > > --- a/Documentation/userspace-api/media/v4l/buffer.rst
> > > +++ b/Documentation/userspace-api/media/v4l/buffer.rst
> > > @@ -438,6 +438,12 @@ enum v4l2_buf_type
> > >      * - ``V4L2_BUF_TYPE_META_OUTPUT``
> > >        - 14
> >
> > >        - Buffer for metadata output, see :ref:`metadata`.
> > > +    * - ``V4L2_BUF_TYPE_AUDIO_CAPTURE``
> > > +      - 15
> > > +      - Buffer for audio capture, see :ref:`audio`.
> > > +    * - ``V4L2_BUF_TYPE_AUDIO_OUTPUT``
> > > +      - 16
> >
> > Hmm... alsa APi define input/output as:
> >         enum {
> >                 SNDRV_PCM_STREAM_PLAYBACK = 0,
> >                 SNDRV_PCM_STREAM_CAPTURE,
> >                 SNDRV_PCM_STREAM_LAST = SNDRV_PCM_STREAM_CAPTURE,
> >         };
> >
> >
> > I would use a namespace as close as possible to the
> > ALSA API. Also, we're not talking about V4L2, but, instead
> > audio. so, not sure if I like the prefix to start with
> > V4L2_. Maybe ALSA_?
> >
> > So, a better namespace would be:
> >
> >         ${prefix}_BUF_TYPE_PCM_STREAM_PLAYBACK
> > and
> >         ${prefix}_BUF_TYPE_PCM_STREAM_CAPTURE
> >
>
> The API is still V4L2, and all the other non-video buf types also use
> the V4L2_ prefix, so perhaps that's good here as well?
>
> Whether AUDIO or PCM_STREAM makes more sense goes outside of my
> expertise. Subjectively, a PCM stream sounds more specific than an
> audio stream. Do those buf types also support non-PCM audio streams?

Currently I use it for PCM,  but I think it can also be used for non-PCM.
So use the below name?
V4L2_BUF_TYPE_AUDIO_CAPTURE
V4L2_BUF_TYPE_AUDIO_PLAYBACK

>
> > > +      - Buffer for audio output, see :ref:`audio`.
> > >
> > >
> > >  .. _buffer-flags:
> > > diff --git a/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst b/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
> > > new file mode 100644
> > > index 000000000000..68faecfe3a02
> > > --- /dev/null
> > > +++ b/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
> > > @@ -0,0 +1,71 @@
> > > +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
> > > +
> > > +.. _audiomem2mem:
> > > +
> > > +********************************
> > > +Audio Memory-To-Memory Interface
> > > +********************************
> > > +
> > > +An audio memory-to-memory device can compress, decompress, transform, or
> > > +otherwise convert audio data from one format into another format, in memory.
> > > +Such memory-to-memory devices set the ``V4L2_CAP_AUDIO_M2M`` capability.
> > > +Examples of memory-to-memory devices are audio codecs, audio preprocessing,
> > > +audio postprocessing.
> > > +
> > > +A memory-to-memory audio node supports both output (sending audio frames from
> > > +memory to the hardware) and capture (receiving the processed audio frames
> > > +from the hardware into memory) stream I/O. An application will have to
> > > +setup the stream I/O for both sides and finally call
> > > +:ref:`VIDIOC_STREAMON <VIDIOC_STREAMON>` for both capture and output to
> > > +start the hardware.
> > > +
> > > +Memory-to-memory devices function as a shared resource: you can
> > > +open the audio node multiple times, each application setting up their
> > > +own properties that are local to the file handle, and each can use
> > > +it independently from the others. The driver will arbitrate access to
> > > +the hardware and reprogram it whenever another file handler gets access.
> > > +
> > > +Audio memory-to-memory devices are accessed through character device
> > > +special files named ``/dev/v4l-audio``
> > > +
> > > +Querying Capabilities
> > > +=====================
> > > +
> > > +Device nodes supporting the audio memory-to-memory interface set the
> > > +``V4L2_CAP_AUDIO_M2M`` flag in the ``device_caps`` field of the
> > > +:c:type:`v4l2_capability` structure returned by the :c:func:`VIDIOC_QUERYCAP`
> > > +ioctl.
> > > +
> > > +Data Format Negotiation
> > > +=======================
> > > +
> > > +The audio device uses the :ref:`format` ioctls to select the capture format.
> > > +The audio buffer content format is bound to that selected format. In addition
> > > +to the basic :ref:`format` ioctls, the :c:func:`VIDIOC_ENUM_FMT` ioctl must be
> > > +supported as well.
> > > +
> > > +To use the :ref:`format` ioctls applications set the ``type`` field of the
> > > +:c:type:`v4l2_format` structure to ``V4L2_BUF_TYPE_AUDIO_CAPTURE`` or to
> > > +``V4L2_BUF_TYPE_AUDIO_OUTPUT``. Both drivers and applications must set the
> > > +remainder of the :c:type:`v4l2_format` structure to 0.
> > > +
> > > +.. c:type:: v4l2_audio_format
> > > +
> > > +.. tabularcolumns:: |p{1.4cm}|p{2.4cm}|p{13.5cm}|
> > > +
> > > +.. flat-table:: struct v4l2_audio_format
> > > +    :header-rows:  0
> > > +    :stub-columns: 0
> > > +    :widths:       1 1 2
> > > +
> > > +    * - __u32
> > > +      - ``pixelformat``
> > > +      - The sample format, set by the application. see :ref:`pixfmt-audio`
> >
> > pixelformat doesn't make any sense for audio: there are no pixels on a
> > PCM stream. Please use call it, instead: `snd_pcm_format`, making it match
> > the values for snd_pcm_format_t.
> >
>
> +1
>
> FWIW v4l2_meta_format uses the name "dataformat".
>
> Actually, I just realized that the C code actually uses the name
> "audioformat". Tbh., after reading the kerneldoc comment, my
> subjective preference would be on "sample_format", since that's
> exactly what it is.
>
Ok, I will change it to sampleformat.

Best Regards
Shengjiu Wang

> > Yet, I would keep defining it as u32 (or u64?) instead of using a
> > typedef int field there (snd_pcm_format_t), as the size of integer
> > is different on 32 and 64 bit kernels.
>
> +1
>
> Best regards,
> Tomasz

Hans Verkuil Feb. 21, 2024, 11:13 a.m. UTC | #6

On 17/02/2024 10:42, Mauro Carvalho Chehab wrote:
> Em Thu, 18 Jan 2024 20:32:00 +0800
> Shengjiu Wang <[e-mail]> escreveu:
> 
>> Audio signal processing has the requirement for memory to
>> memory similar as Video.
>>
>> This patch is to add this support in v4l2 framework, defined
>> new buffer type V4L2_BUF_TYPE_AUDIO_CAPTURE and
>> V4L2_BUF_TYPE_AUDIO_OUTPUT, defined new format v4l2_audio_format
>> for audio case usage.
>>
>> The created audio device is named "/dev/v4l-audioX".
>>
>> Signed-off-by: Shengjiu Wang <[e-mail]>
>> ---
>>  .../userspace-api/media/v4l/buffer.rst        |  6 ++
>>  .../media/v4l/dev-audio-mem2mem.rst           | 71 +++++++++++++++++++
>>  .../userspace-api/media/v4l/devices.rst       |  1 +
>>  .../media/v4l/vidioc-enum-fmt.rst             |  2 +
>>  .../userspace-api/media/v4l/vidioc-g-fmt.rst  |  4 ++
>>  .../media/videodev2.h.rst.exceptions          |  2 +
>>  .../media/common/videobuf2/videobuf2-v4l2.c   |  4 ++
>>  drivers/media/v4l2-core/v4l2-compat-ioctl32.c |  9 +++
>>  drivers/media/v4l2-core/v4l2-dev.c            | 17 +++++
>>  drivers/media/v4l2-core/v4l2-ioctl.c          | 53 ++++++++++++++
>>  include/media/v4l2-dev.h                      |  2 +
>>  include/media/v4l2-ioctl.h                    | 34 +++++++++
>>  include/uapi/linux/videodev2.h                | 17 +++++
>>  13 files changed, 222 insertions(+)
>>  create mode 100644 Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
>>
>> diff --git a/Documentation/userspace-api/media/v4l/buffer.rst b/Documentation/userspace-api/media/v4l/buffer.rst
>> index 52bbee81c080..a3754ca6f0d6 100644
>> --- a/Documentation/userspace-api/media/v4l/buffer.rst
>> +++ b/Documentation/userspace-api/media/v4l/buffer.rst
>> @@ -438,6 +438,12 @@ enum v4l2_buf_type
>>      * - ``V4L2_BUF_TYPE_META_OUTPUT``
>>        - 14
> 
>>        - Buffer for metadata output, see :ref:`metadata`.
>> +    * - ``V4L2_BUF_TYPE_AUDIO_CAPTURE``
>> +      - 15
>> +      - Buffer for audio capture, see :ref:`audio`.
>> +    * - ``V4L2_BUF_TYPE_AUDIO_OUTPUT``
>> +      - 16
> 
> Hmm... alsa APi define input/output as:
> 	enum {
> 	        SNDRV_PCM_STREAM_PLAYBACK = 0,
> 	        SNDRV_PCM_STREAM_CAPTURE,
> 	        SNDRV_PCM_STREAM_LAST = SNDRV_PCM_STREAM_CAPTURE,
> 	};
> 
> 
> I would use a namespace as close as possible to the
> ALSA API. Also, we're not talking about V4L2, but, instead
> audio. so, not sure if I like the prefix to start with
> V4L2_. Maybe ALSA_?
> 
> So, a better namespace would be:
> 
> 	${prefix}_BUF_TYPE_PCM_STREAM_PLAYBACK
> and
> 	${prefix}_BUF_TYPE_PCM_STREAM_CAPTURE
> 
>> +      - Buffer for audio output, see :ref:`audio`.
>>  
>>  
>>  .. _buffer-flags:
>> diff --git a/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst b/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
>> new file mode 100644
>> index 000000000000..68faecfe3a02
>> --- /dev/null
>> +++ b/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
>> @@ -0,0 +1,71 @@
>> +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
>> +
>> +.. _audiomem2mem:
>> +
>> +********************************
>> +Audio Memory-To-Memory Interface
>> +********************************
>> +
>> +An audio memory-to-memory device can compress, decompress, transform, or
>> +otherwise convert audio data from one format into another format, in memory.
>> +Such memory-to-memory devices set the ``V4L2_CAP_AUDIO_M2M`` capability.
>> +Examples of memory-to-memory devices are audio codecs, audio preprocessing,
>> +audio postprocessing.
>> +
>> +A memory-to-memory audio node supports both output (sending audio frames from
>> +memory to the hardware) and capture (receiving the processed audio frames
>> +from the hardware into memory) stream I/O. An application will have to
>> +setup the stream I/O for both sides and finally call
>> +:ref:`VIDIOC_STREAMON <VIDIOC_STREAMON>` for both capture and output to
>> +start the hardware.
>> +
>> +Memory-to-memory devices function as a shared resource: you can
>> +open the audio node multiple times, each application setting up their
>> +own properties that are local to the file handle, and each can use
>> +it independently from the others. The driver will arbitrate access to
>> +the hardware and reprogram it whenever another file handler gets access.
>> +
>> +Audio memory-to-memory devices are accessed through character device
>> +special files named ``/dev/v4l-audio``
>> +
>> +Querying Capabilities
>> +=====================
>> +
>> +Device nodes supporting the audio memory-to-memory interface set the
>> +``V4L2_CAP_AUDIO_M2M`` flag in the ``device_caps`` field of the
>> +:c:type:`v4l2_capability` structure returned by the :c:func:`VIDIOC_QUERYCAP`
>> +ioctl.
>> +
>> +Data Format Negotiation
>> +=======================
>> +
>> +The audio device uses the :ref:`format` ioctls to select the capture format.
>> +The audio buffer content format is bound to that selected format. In addition
>> +to the basic :ref:`format` ioctls, the :c:func:`VIDIOC_ENUM_FMT` ioctl must be
>> +supported as well.
>> +
>> +To use the :ref:`format` ioctls applications set the ``type`` field of the
>> +:c:type:`v4l2_format` structure to ``V4L2_BUF_TYPE_AUDIO_CAPTURE`` or to
>> +``V4L2_BUF_TYPE_AUDIO_OUTPUT``. Both drivers and applications must set the
>> +remainder of the :c:type:`v4l2_format` structure to 0.
>> +
>> +.. c:type:: v4l2_audio_format
>> +
>> +.. tabularcolumns:: |p{1.4cm}|p{2.4cm}|p{13.5cm}|
>> +
>> +.. flat-table:: struct v4l2_audio_format
>> +    :header-rows:  0
>> +    :stub-columns: 0
>> +    :widths:       1 1 2
>> +
>> +    * - __u32
>> +      - ``pixelformat``
>> +      - The sample format, set by the application. see :ref:`pixfmt-audio`
> 
> pixelformat doesn't make any sense for audio: there are no pixels on a

Ah, that's a doc bug: this field is called audioformat in the struct, not
pixelformat. I missed this one in my review.

Regards,

	Hans

> PCM stream. Please use call it, instead: `snd_pcm_format`, making it match
> the values for snd_pcm_format_t.
> 
> Yet, I would keep defining it as u32 (or u64?) instead of using a
> typedef int field there (snd_pcm_format_t), as the size of integer
> is different on 32 and 64 bit kernels.
> 
> 
>> +    * - __u32
>> +      - ``channels``
>> +      - The channel number, set by the application. channel number range is
>> +        [1, 32].
> 
> Why not start on zero?
> 
>> +    * - __u32
>> +      - ``buffersize``
>> +      - Maximum buffer size in bytes required for data. The value is set by the
>> +        driver.
>> diff --git a/Documentation/userspace-api/media/v4l/devices.rst b/Documentation/userspace-api/media/v4l/devices.rst
>> index 8bfbad65a9d4..758bd90f1c26 100644
>> --- a/Documentation/userspace-api/media/v4l/devices.rst
>> +++ b/Documentation/userspace-api/media/v4l/devices.rst
>> @@ -24,3 +24,4 @@ Interfaces
>>      dev-event
>>      dev-subdev
>>      dev-meta
>> +    dev-audio-mem2mem
>> diff --git a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
>> index 000c154b0f98..42deb07f4ff4 100644
>> --- a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
>> +++ b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
>> @@ -96,6 +96,8 @@ the ``mbus_code`` field is handled differently:
>>  	``V4L2_BUF_TYPE_VIDEO_OVERLAY``,
>>  	``V4L2_BUF_TYPE_SDR_CAPTURE``,
>>  	``V4L2_BUF_TYPE_SDR_OUTPUT``,
>> +	``V4L2_BUF_TYPE_AUDIO_CAPTURE``,
>> +	``V4L2_BUF_TYPE_AUDIO_OUTPUT``,
>>  	``V4L2_BUF_TYPE_META_CAPTURE`` and
>>  	``V4L2_BUF_TYPE_META_OUTPUT``.
>>  	See :c:type:`v4l2_buf_type`.
>> diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-fmt.rst b/Documentation/userspace-api/media/v4l/vidioc-g-fmt.rst
>> index 675c385e5aca..528fd9df41aa 100644
>> --- a/Documentation/userspace-api/media/v4l/vidioc-g-fmt.rst
>> +++ b/Documentation/userspace-api/media/v4l/vidioc-g-fmt.rst
>> @@ -130,6 +130,10 @@ The format as returned by :ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>` must be identical
>>        - ``meta``
>>        - Definition of a metadata format, see :ref:`meta-formats`, used by
>>  	metadata capture devices.
>> +    * - struct :c:type:`v4l2_audio_format`
>> +      - ``audio``
>> +      - Definition of a audio data format, see :ref:`audiomem2mem`, used by
>> +        audio memory-to-memory devices
>>      * - __u8
>>        - ``raw_data``\ [200]
>>        - Place holder for future extensions.
>> diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
>> index da6d0b8e4c2c..e61152bb80d1 100644
>> --- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
>> +++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
>> @@ -29,6 +29,8 @@ replace symbol V4L2_FIELD_SEQ_TB :c:type:`v4l2_field`
>>  replace symbol V4L2_FIELD_TOP :c:type:`v4l2_field`
>>  
>>  # Documented enum v4l2_buf_type
>> +replace symbol V4L2_BUF_TYPE_AUDIO_CAPTURE :c:type:`v4l2_buf_type`
>> +replace symbol V4L2_BUF_TYPE_AUDIO_OUTPUT :c:type:`v4l2_buf_type`
>>  replace symbol V4L2_BUF_TYPE_META_CAPTURE :c:type:`v4l2_buf_type`
>>  replace symbol V4L2_BUF_TYPE_META_OUTPUT :c:type:`v4l2_buf_type`
>>  replace symbol V4L2_BUF_TYPE_SDR_CAPTURE :c:type:`v4l2_buf_type`
>> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
>> index 54d572c3b515..16ab204d15b0 100644
>> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
>> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
>> @@ -791,6 +791,10 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
>>  	case V4L2_BUF_TYPE_META_OUTPUT:
>>  		requested_sizes[0] = f->fmt.meta.buffersize;
>>  		break;
>> +	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
>> +	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
>> +		requested_sizes[0] = f->fmt.audio.buffersize;
>> +		break;
>>  	default:
>>  		return -EINVAL;
>>  	}
>> diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
>> index 8c07400bd280..5e94db8dfdae 100644
>> --- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
>> +++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
>> @@ -101,6 +101,7 @@ struct v4l2_format32 {
>>  		struct v4l2_sliced_vbi_format	sliced;
>>  		struct v4l2_sdr_format	sdr;
>>  		struct v4l2_meta_format	meta;
>> +		struct v4l2_audio_format	audio;
>>  		__u8	raw_data[200];        /* user-defined */
>>  	} fmt;
>>  };
>> @@ -166,6 +167,10 @@ static int get_v4l2_format32(struct v4l2_format *p64,
>>  	case V4L2_BUF_TYPE_META_OUTPUT:
>>  		return copy_from_user(&p64->fmt.meta, &p32->fmt.meta,
>>  				      sizeof(p64->fmt.meta)) ? -EFAULT : 0;
>> +	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
>> +	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
>> +		return copy_from_user(&p64->fmt.audio, &p32->fmt.audio,
>> +				      sizeof(p64->fmt.audio)) ? -EFAULT : 0;
>>  	default:
>>  		return -EINVAL;
>>  	}
>> @@ -216,6 +221,10 @@ static int put_v4l2_format32(struct v4l2_format *p64,
>>  	case V4L2_BUF_TYPE_META_OUTPUT:
>>  		return copy_to_user(&p32->fmt.meta, &p64->fmt.meta,
>>  				    sizeof(p64->fmt.meta)) ? -EFAULT : 0;
>> +	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
>> +	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
>> +		return copy_to_user(&p32->fmt.audio, &p64->fmt.audio,
>> +				    sizeof(p64->fmt.audio)) ? -EFAULT : 0;
>>  	default:
>>  		return -EINVAL;
>>  	}
>> diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
>> index d13954bd31fd..bac008fcedc6 100644
>> --- a/drivers/media/v4l2-core/v4l2-dev.c
>> +++ b/drivers/media/v4l2-core/v4l2-dev.c
>> @@ -553,6 +553,7 @@ static void determine_valid_ioctls(struct video_device *vdev)
>>  	bool is_tch = vdev->vfl_type == VFL_TYPE_TOUCH;
>>  	bool is_meta = vdev->vfl_type == VFL_TYPE_VIDEO &&
>>  		       (vdev->device_caps & meta_caps);
>> +	bool is_audio = vdev->vfl_type == VFL_TYPE_AUDIO;
>>  	bool is_rx = vdev->vfl_dir != VFL_DIR_TX;
>>  	bool is_tx = vdev->vfl_dir != VFL_DIR_RX;
>>  	bool is_io_mc = vdev->device_caps & V4L2_CAP_IO_MC;
>> @@ -666,6 +667,19 @@ static void determine_valid_ioctls(struct video_device *vdev)
>>  		SET_VALID_IOCTL(ops, VIDIOC_S_FMT, vidioc_s_fmt_meta_out);
>>  		SET_VALID_IOCTL(ops, VIDIOC_TRY_FMT, vidioc_try_fmt_meta_out);
>>  	}
>> +	if (is_audio && is_rx) {
>> +		/* audio capture specific ioctls */
>> +		SET_VALID_IOCTL(ops, VIDIOC_ENUM_FMT, vidioc_enum_fmt_audio_cap);
>> +		SET_VALID_IOCTL(ops, VIDIOC_G_FMT, vidioc_g_fmt_audio_cap);
>> +		SET_VALID_IOCTL(ops, VIDIOC_S_FMT, vidioc_s_fmt_audio_cap);
>> +		SET_VALID_IOCTL(ops, VIDIOC_TRY_FMT, vidioc_try_fmt_audio_cap);
>> +	} else if (is_audio && is_tx) {
>> +		/* audio output specific ioctls */
>> +		SET_VALID_IOCTL(ops, VIDIOC_ENUM_FMT, vidioc_enum_fmt_audio_out);
>> +		SET_VALID_IOCTL(ops, VIDIOC_G_FMT, vidioc_g_fmt_audio_out);
>> +		SET_VALID_IOCTL(ops, VIDIOC_S_FMT, vidioc_s_fmt_audio_out);
>> +		SET_VALID_IOCTL(ops, VIDIOC_TRY_FMT, vidioc_try_fmt_audio_out);
>> +	}
>>  	if (is_vbi) {
>>  		/* vbi specific ioctls */
>>  		if ((is_rx && (ops->vidioc_g_fmt_vbi_cap ||
>> @@ -929,6 +943,9 @@ int __video_register_device(struct video_device *vdev,
>>  	case VFL_TYPE_TOUCH:
>>  		name_base = "v4l-touch";
>>  		break;
>> +	case VFL_TYPE_AUDIO:
>> +		name_base = "v4l-audio";
>> +		break;
>>  	default:
>>  		pr_err("%s called with unknown type: %d\n",
>>  		       __func__, type);
>> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
>> index 33076af4dfdb..e7be7c2f302d 100644
>> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
>> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
>> @@ -188,6 +188,8 @@ const char *v4l2_type_names[] = {
>>  	[V4L2_BUF_TYPE_SDR_OUTPUT]         = "sdr-out",
>>  	[V4L2_BUF_TYPE_META_CAPTURE]       = "meta-cap",
>>  	[V4L2_BUF_TYPE_META_OUTPUT]	   = "meta-out",
>> +	[V4L2_BUF_TYPE_AUDIO_CAPTURE]      = "audio-cap",
>> +	[V4L2_BUF_TYPE_AUDIO_OUTPUT]	   = "audio-out",
>>  };
>>  EXPORT_SYMBOL(v4l2_type_names);
>>  
>> @@ -276,6 +278,7 @@ static void v4l_print_format(const void *arg, bool write_only)
>>  	const struct v4l2_sliced_vbi_format *sliced;
>>  	const struct v4l2_window *win;
>>  	const struct v4l2_meta_format *meta;
>> +	const struct v4l2_audio_format *audio;
>>  	u32 pixelformat;
>>  	u32 planes;
>>  	unsigned i;
>> @@ -346,6 +349,13 @@ static void v4l_print_format(const void *arg, bool write_only)
>>  		pr_cont(", dataformat=%p4cc, buffersize=%u\n",
>>  			&pixelformat, meta->buffersize);
>>  		break;
>> +	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
>> +	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
>> +		audio = &p->fmt.audio;
>> +		pixelformat = audio->audioformat;
>> +		pr_cont(", format=%p4cc, channels=%u, buffersize=%u\n",
>> +			&pixelformat, audio->channels, audio->buffersize);
>> +		break;
>>  	}
>>  }
>>  
>> @@ -927,6 +937,7 @@ static int check_fmt(struct file *file, enum v4l2_buf_type type)
>>  	bool is_tch = vfd->vfl_type == VFL_TYPE_TOUCH;
>>  	bool is_meta = vfd->vfl_type == VFL_TYPE_VIDEO &&
>>  		       (vfd->device_caps & meta_caps);
>> +	bool is_audio = vfd->vfl_type == VFL_TYPE_AUDIO;
>>  	bool is_rx = vfd->vfl_dir != VFL_DIR_TX;
>>  	bool is_tx = vfd->vfl_dir != VFL_DIR_RX;
>>  
>> @@ -992,6 +1003,14 @@ static int check_fmt(struct file *file, enum v4l2_buf_type type)
>>  		if (is_meta && is_tx && ops->vidioc_g_fmt_meta_out)
>>  			return 0;
>>  		break;
>> +	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
>> +		if (is_audio && is_rx && ops->vidioc_g_fmt_audio_cap)
>> +			return 0;
>> +		break;
>> +	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
>> +		if (is_audio && is_tx && ops->vidioc_g_fmt_audio_out)
>> +			return 0;
>> +		break;
>>  	default:
>>  		break;
>>  	}
>> @@ -1597,6 +1616,16 @@ static int v4l_enum_fmt(const struct v4l2_ioctl_ops *ops,
>>  			break;
>>  		ret = ops->vidioc_enum_fmt_meta_out(file, fh, arg);
>>  		break;
>> +	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
>> +		if (unlikely(!ops->vidioc_enum_fmt_audio_cap))
>> +			break;
>> +		ret = ops->vidioc_enum_fmt_audio_cap(file, fh, arg);
>> +		break;
>> +	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
>> +		if (unlikely(!ops->vidioc_enum_fmt_audio_out))
>> +			break;
>> +		ret = ops->vidioc_enum_fmt_audio_out(file, fh, arg);
>> +		break;
>>  	}
>>  	if (ret == 0)
>>  		v4l_fill_fmtdesc(p);
>> @@ -1673,6 +1702,10 @@ static int v4l_g_fmt(const struct v4l2_ioctl_ops *ops,
>>  		return ops->vidioc_g_fmt_meta_cap(file, fh, arg);
>>  	case V4L2_BUF_TYPE_META_OUTPUT:
>>  		return ops->vidioc_g_fmt_meta_out(file, fh, arg);
>> +	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
>> +		return ops->vidioc_g_fmt_audio_cap(file, fh, arg);
>> +	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
>> +		return ops->vidioc_g_fmt_audio_out(file, fh, arg);
>>  	}
>>  	return -EINVAL;
>>  }
>> @@ -1784,6 +1817,16 @@ static int v4l_s_fmt(const struct v4l2_ioctl_ops *ops,
>>  			break;
>>  		memset_after(p, 0, fmt.meta);
>>  		return ops->vidioc_s_fmt_meta_out(file, fh, arg);
>> +	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
>> +		if (unlikely(!ops->vidioc_s_fmt_audio_cap))
>> +			break;
>> +		memset_after(p, 0, fmt.audio);
>> +		return ops->vidioc_s_fmt_audio_cap(file, fh, arg);
>> +	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
>> +		if (unlikely(!ops->vidioc_s_fmt_audio_out))
>> +			break;
>> +		memset_after(p, 0, fmt.audio);
>> +		return ops->vidioc_s_fmt_audio_out(file, fh, arg);
>>  	}
>>  	return -EINVAL;
>>  }
>> @@ -1892,6 +1935,16 @@ static int v4l_try_fmt(const struct v4l2_ioctl_ops *ops,
>>  			break;
>>  		memset_after(p, 0, fmt.meta);
>>  		return ops->vidioc_try_fmt_meta_out(file, fh, arg);
>> +	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
>> +		if (unlikely(!ops->vidioc_try_fmt_audio_cap))
>> +			break;
>> +		memset_after(p, 0, fmt.audio);
>> +		return ops->vidioc_try_fmt_audio_cap(file, fh, arg);
>> +	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
>> +		if (unlikely(!ops->vidioc_try_fmt_audio_out))
>> +			break;
>> +		memset_after(p, 0, fmt.audio);
>> +		return ops->vidioc_try_fmt_audio_out(file, fh, arg);
>>  	}
>>  	return -EINVAL;
>>  }
>> diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h
>> index d82dfdbf6e58..82b63f82d43f 100644
>> --- a/include/media/v4l2-dev.h
>> +++ b/include/media/v4l2-dev.h
>> @@ -30,6 +30,7 @@
>>   * @VFL_TYPE_SUBDEV:	for V4L2 subdevices
>>   * @VFL_TYPE_SDR:	for Software Defined Radio tuners
>>   * @VFL_TYPE_TOUCH:	for touch sensors
>> + * @VFL_TYPE_AUDIO:	for audio memory-to-memory devices
>>   * @VFL_TYPE_MAX:	number of VFL types, must always be last in the enum
>>   */
>>  enum vfl_devnode_type {
>> @@ -39,6 +40,7 @@ enum vfl_devnode_type {
>>  	VFL_TYPE_SUBDEV,
>>  	VFL_TYPE_SDR,
>>  	VFL_TYPE_TOUCH,
>> +	VFL_TYPE_AUDIO,
>>  	VFL_TYPE_MAX /* Shall be the last one */
>>  };
>>  
>> diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
>> index edb733f21604..f840cf740ce1 100644
>> --- a/include/media/v4l2-ioctl.h
>> +++ b/include/media/v4l2-ioctl.h
>> @@ -45,6 +45,12 @@ struct v4l2_fh;
>>   * @vidioc_enum_fmt_meta_out: pointer to the function that implements
>>   *	:ref:`VIDIOC_ENUM_FMT <vidioc_enum_fmt>` ioctl logic
>>   *	for metadata output
>> + * @vidioc_enum_fmt_audio_cap: pointer to the function that implements
>> + *	:ref:`VIDIOC_ENUM_FMT <vidioc_enum_fmt>` ioctl logic
>> + *	for audio capture
>> + * @vidioc_enum_fmt_audio_out: pointer to the function that implements
>> + *	:ref:`VIDIOC_ENUM_FMT <vidioc_enum_fmt>` ioctl logic
>> + *	for audio output
>>   * @vidioc_g_fmt_vid_cap: pointer to the function that implements
>>   *	:ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for video capture
>>   *	in single plane mode
>> @@ -79,6 +85,10 @@ struct v4l2_fh;
>>   *	:ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for metadata capture
>>   * @vidioc_g_fmt_meta_out: pointer to the function that implements
>>   *	:ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for metadata output
>> + * @vidioc_g_fmt_audio_cap: pointer to the function that implements
>> + *	:ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for audio capture
>> + * @vidioc_g_fmt_audio_out: pointer to the function that implements
>> + *	:ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for audio output
>>   * @vidioc_s_fmt_vid_cap: pointer to the function that implements
>>   *	:ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for video capture
>>   *	in single plane mode
>> @@ -113,6 +123,10 @@ struct v4l2_fh;
>>   *	:ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for metadata capture
>>   * @vidioc_s_fmt_meta_out: pointer to the function that implements
>>   *	:ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for metadata output
>> + * @vidioc_s_fmt_audio_cap: pointer to the function that implements
>> + *	:ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for audio capture
>> + * @vidioc_s_fmt_audio_out: pointer to the function that implements
>> + *	:ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for audio output
>>   * @vidioc_try_fmt_vid_cap: pointer to the function that implements
>>   *	:ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for video capture
>>   *	in single plane mode
>> @@ -149,6 +163,10 @@ struct v4l2_fh;
>>   *	:ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for metadata capture
>>   * @vidioc_try_fmt_meta_out: pointer to the function that implements
>>   *	:ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for metadata output
>> + * @vidioc_try_fmt_audio_cap: pointer to the function that implements
>> + *	:ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for audio capture
>> + * @vidioc_try_fmt_audio_out: pointer to the function that implements
>> + *	:ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for audio output
>>   * @vidioc_reqbufs: pointer to the function that implements
>>   *	:ref:`VIDIOC_REQBUFS <vidioc_reqbufs>` ioctl
>>   * @vidioc_querybuf: pointer to the function that implements
>> @@ -315,6 +333,10 @@ struct v4l2_ioctl_ops {
>>  					struct v4l2_fmtdesc *f);
>>  	int (*vidioc_enum_fmt_meta_out)(struct file *file, void *fh,
>>  					struct v4l2_fmtdesc *f);
>> +	int (*vidioc_enum_fmt_audio_cap)(struct file *file, void *fh,
>> +					 struct v4l2_fmtdesc *f);
>> +	int (*vidioc_enum_fmt_audio_out)(struct file *file, void *fh,
>> +					 struct v4l2_fmtdesc *f);
>>  
>>  	/* VIDIOC_G_FMT handlers */
>>  	int (*vidioc_g_fmt_vid_cap)(struct file *file, void *fh,
>> @@ -345,6 +367,10 @@ struct v4l2_ioctl_ops {
>>  				     struct v4l2_format *f);
>>  	int (*vidioc_g_fmt_meta_out)(struct file *file, void *fh,
>>  				     struct v4l2_format *f);
>> +	int (*vidioc_g_fmt_audio_cap)(struct file *file, void *fh,
>> +				      struct v4l2_format *f);
>> +	int (*vidioc_g_fmt_audio_out)(struct file *file, void *fh,
>> +				      struct v4l2_format *f);
>>  
>>  	/* VIDIOC_S_FMT handlers */
>>  	int (*vidioc_s_fmt_vid_cap)(struct file *file, void *fh,
>> @@ -375,6 +401,10 @@ struct v4l2_ioctl_ops {
>>  				     struct v4l2_format *f);
>>  	int (*vidioc_s_fmt_meta_out)(struct file *file, void *fh,
>>  				     struct v4l2_format *f);
>> +	int (*vidioc_s_fmt_audio_cap)(struct file *file, void *fh,
>> +				      struct v4l2_format *f);
>> +	int (*vidioc_s_fmt_audio_out)(struct file *file, void *fh,
>> +				      struct v4l2_format *f);
>>  
>>  	/* VIDIOC_TRY_FMT handlers */
>>  	int (*vidioc_try_fmt_vid_cap)(struct file *file, void *fh,
>> @@ -405,6 +435,10 @@ struct v4l2_ioctl_ops {
>>  				       struct v4l2_format *f);
>>  	int (*vidioc_try_fmt_meta_out)(struct file *file, void *fh,
>>  				       struct v4l2_format *f);
>> +	int (*vidioc_try_fmt_audio_cap)(struct file *file, void *fh,
>> +					struct v4l2_format *f);
>> +	int (*vidioc_try_fmt_audio_out)(struct file *file, void *fh,
>> +					struct v4l2_format *f);
>>  
>>  	/* Buffer handlers */
>>  	int (*vidioc_reqbufs)(struct file *file, void *fh,
>> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
>> index 6cd65969c2b5..57c82eb158f1 100644
>> --- a/include/uapi/linux/videodev2.h
>> +++ b/include/uapi/linux/videodev2.h
>> @@ -153,6 +153,8 @@ enum v4l2_buf_type {
>>  	V4L2_BUF_TYPE_SDR_OUTPUT           = 12,
>>  	V4L2_BUF_TYPE_META_CAPTURE         = 13,
>>  	V4L2_BUF_TYPE_META_OUTPUT	   = 14,
>> +	V4L2_BUF_TYPE_AUDIO_CAPTURE        = 15,
>> +	V4L2_BUF_TYPE_AUDIO_OUTPUT         = 16,
>>  	/* Deprecated, do not use */
>>  	V4L2_BUF_TYPE_PRIVATE              = 0x80,
>>  };
>> @@ -169,6 +171,7 @@ enum v4l2_buf_type {
>>  	 || (type) == V4L2_BUF_TYPE_VBI_OUTPUT			\
>>  	 || (type) == V4L2_BUF_TYPE_SLICED_VBI_OUTPUT		\
>>  	 || (type) == V4L2_BUF_TYPE_SDR_OUTPUT			\
>> +	 || (type) == V4L2_BUF_TYPE_AUDIO_OUTPUT		\
>>  	 || (type) == V4L2_BUF_TYPE_META_OUTPUT)
>>  
>>  #define V4L2_TYPE_IS_CAPTURE(type) (!V4L2_TYPE_IS_OUTPUT(type))
>> @@ -2423,6 +2426,18 @@ struct v4l2_meta_format {
>>  	__u32				buffersize;
>>  } __attribute__ ((packed));
>>  
>> +/**
>> + * struct v4l2_audio_format - audio data format definition
>> + * @audioformat:	little endian four character code (fourcc)
> 
> Don't use fourcc here. Instead, use the types defined at snd_pcm_format_t.
> 
>> + * @channels:		channel numbers
>> + * @buffersize:		maximum size in bytes required for data
>> + */
>> +struct v4l2_audio_format {
>> +	__u32				audioformat;
>> +	__u32				channels;
>> +	__u32				buffersize;
>> +} __attribute__ ((packed));
>> +
>>  /**
>>   * struct v4l2_format - stream data format
>>   * @type:	enum v4l2_buf_type; type of the data stream
>> @@ -2431,6 +2446,7 @@ struct v4l2_meta_format {
>>   * @win:	definition of an overlaid image
>>   * @vbi:	raw VBI capture or output parameters
>>   * @sliced:	sliced VBI capture or output parameters
>> + * @audio:	definition of an audio format
>>   * @raw_data:	placeholder for future extensions and custom formats
>>   * @fmt:	union of @pix, @pix_mp, @win, @vbi, @sliced, @sdr, @meta
>>   *		and @raw_data
>> @@ -2445,6 +2461,7 @@ struct v4l2_format {
>>  		struct v4l2_sliced_vbi_format	sliced;  /* V4L2_BUF_TYPE_SLICED_VBI_CAPTURE */
>>  		struct v4l2_sdr_format		sdr;     /* V4L2_BUF_TYPE_SDR_CAPTURE */
>>  		struct v4l2_meta_format		meta;    /* V4L2_BUF_TYPE_META_CAPTURE */
>> +		struct v4l2_audio_format	audio;   /* V4L2_BUF_TYPE_AUDIO_CAPTURE */
>>  		__u8	raw_data[200];                   /* user-defined */
>>  	} fmt;
>>  };
> 
> 
> 
> Thanks,
> Mauro

Hans Verkuil Feb. 21, 2024, 11:16 a.m. UTC | #7

On 21/02/2024 11:11, Shengjiu Wang wrote:
> On Wed, Feb 21, 2024 at 12:30 PM Tomasz Figa <[e-mail]> wrote:
>>
>> On Sat, Feb 17, 2024 at 6:42 PM Mauro Carvalho Chehab
>> <[e-mail]> wrote:
>>>
>>> Em Thu, 18 Jan 2024 20:32:00 +0800
>>> Shengjiu Wang <[e-mail]> escreveu:
>>>
>>>> Audio signal processing has the requirement for memory to
>>>> memory similar as Video.
>>>>
>>>> This patch is to add this support in v4l2 framework, defined
>>>> new buffer type V4L2_BUF_TYPE_AUDIO_CAPTURE and
>>>> V4L2_BUF_TYPE_AUDIO_OUTPUT, defined new format v4l2_audio_format
>>>> for audio case usage.
>>>>
>>>> The created audio device is named "/dev/v4l-audioX".
>>>>
>>>> Signed-off-by: Shengjiu Wang <[e-mail]>
>>>> ---
>>>>  .../userspace-api/media/v4l/buffer.rst        |  6 ++
>>>>  .../media/v4l/dev-audio-mem2mem.rst           | 71 +++++++++++++++++++
>>>>  .../userspace-api/media/v4l/devices.rst       |  1 +
>>>>  .../media/v4l/vidioc-enum-fmt.rst             |  2 +
>>>>  .../userspace-api/media/v4l/vidioc-g-fmt.rst  |  4 ++
>>>>  .../media/videodev2.h.rst.exceptions          |  2 +
>>>>  .../media/common/videobuf2/videobuf2-v4l2.c   |  4 ++
>>>>  drivers/media/v4l2-core/v4l2-compat-ioctl32.c |  9 +++
>>>>  drivers/media/v4l2-core/v4l2-dev.c            | 17 +++++
>>>>  drivers/media/v4l2-core/v4l2-ioctl.c          | 53 ++++++++++++++
>>>>  include/media/v4l2-dev.h                      |  2 +
>>>>  include/media/v4l2-ioctl.h                    | 34 +++++++++
>>>>  include/uapi/linux/videodev2.h                | 17 +++++
>>>>  13 files changed, 222 insertions(+)
>>>>  create mode 100644 Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
>>>>
>>>> diff --git a/Documentation/userspace-api/media/v4l/buffer.rst b/Documentation/userspace-api/media/v4l/buffer.rst
>>>> index 52bbee81c080..a3754ca6f0d6 100644
>>>> --- a/Documentation/userspace-api/media/v4l/buffer.rst
>>>> +++ b/Documentation/userspace-api/media/v4l/buffer.rst
>>>> @@ -438,6 +438,12 @@ enum v4l2_buf_type
>>>>      * - ``V4L2_BUF_TYPE_META_OUTPUT``
>>>>        - 14
>>>
>>>>        - Buffer for metadata output, see :ref:`metadata`.
>>>> +    * - ``V4L2_BUF_TYPE_AUDIO_CAPTURE``
>>>> +      - 15
>>>> +      - Buffer for audio capture, see :ref:`audio`.
>>>> +    * - ``V4L2_BUF_TYPE_AUDIO_OUTPUT``
>>>> +      - 16
>>>
>>> Hmm... alsa APi define input/output as:
>>>         enum {
>>>                 SNDRV_PCM_STREAM_PLAYBACK = 0,
>>>                 SNDRV_PCM_STREAM_CAPTURE,
>>>                 SNDRV_PCM_STREAM_LAST = SNDRV_PCM_STREAM_CAPTURE,
>>>         };
>>>
>>>
>>> I would use a namespace as close as possible to the
>>> ALSA API. Also, we're not talking about V4L2, but, instead
>>> audio. so, not sure if I like the prefix to start with
>>> V4L2_. Maybe ALSA_?
>>>
>>> So, a better namespace would be:
>>>
>>>         ${prefix}_BUF_TYPE_PCM_STREAM_PLAYBACK
>>> and
>>>         ${prefix}_BUF_TYPE_PCM_STREAM_CAPTURE
>>>
>>
>> The API is still V4L2, and all the other non-video buf types also use
>> the V4L2_ prefix, so perhaps that's good here as well?
>>
>> Whether AUDIO or PCM_STREAM makes more sense goes outside of my
>> expertise. Subjectively, a PCM stream sounds more specific than an
>> audio stream. Do those buf types also support non-PCM audio streams?
> 
> Currently I use it for PCM,  but I think it can also be used for non-PCM.
> So use the below name?
> V4L2_BUF_TYPE_AUDIO_CAPTURE
> V4L2_BUF_TYPE_AUDIO_PLAYBACK

I really prefer keeping the names as they are in this patch. CAPTURE/OUTPUT
is consistent with V4L2 nomenclature, and since this is a M2M device 'PLAYBACK'
isn't really a good name either. It's not an audio playback device, it's a
rate converter.

Regards,

	Hans

> 
>>
>>>> +      - Buffer for audio output, see :ref:`audio`.
>>>>
>>>>
>>>>  .. _buffer-flags:
>>>> diff --git a/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst b/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
>>>> new file mode 100644
>>>> index 000000000000..68faecfe3a02
>>>> --- /dev/null
>>>> +++ b/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
>>>> @@ -0,0 +1,71 @@
>>>> +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
>>>> +
>>>> +.. _audiomem2mem:
>>>> +
>>>> +********************************
>>>> +Audio Memory-To-Memory Interface
>>>> +********************************
>>>> +
>>>> +An audio memory-to-memory device can compress, decompress, transform, or
>>>> +otherwise convert audio data from one format into another format, in memory.
>>>> +Such memory-to-memory devices set the ``V4L2_CAP_AUDIO_M2M`` capability.
>>>> +Examples of memory-to-memory devices are audio codecs, audio preprocessing,
>>>> +audio postprocessing.
>>>> +
>>>> +A memory-to-memory audio node supports both output (sending audio frames from
>>>> +memory to the hardware) and capture (receiving the processed audio frames
>>>> +from the hardware into memory) stream I/O. An application will have to
>>>> +setup the stream I/O for both sides and finally call
>>>> +:ref:`VIDIOC_STREAMON <VIDIOC_STREAMON>` for both capture and output to
>>>> +start the hardware.
>>>> +
>>>> +Memory-to-memory devices function as a shared resource: you can
>>>> +open the audio node multiple times, each application setting up their
>>>> +own properties that are local to the file handle, and each can use
>>>> +it independently from the others. The driver will arbitrate access to
>>>> +the hardware and reprogram it whenever another file handler gets access.
>>>> +
>>>> +Audio memory-to-memory devices are accessed through character device
>>>> +special files named ``/dev/v4l-audio``
>>>> +
>>>> +Querying Capabilities
>>>> +=====================
>>>> +
>>>> +Device nodes supporting the audio memory-to-memory interface set the
>>>> +``V4L2_CAP_AUDIO_M2M`` flag in the ``device_caps`` field of the
>>>> +:c:type:`v4l2_capability` structure returned by the :c:func:`VIDIOC_QUERYCAP`
>>>> +ioctl.
>>>> +
>>>> +Data Format Negotiation
>>>> +=======================
>>>> +
>>>> +The audio device uses the :ref:`format` ioctls to select the capture format.
>>>> +The audio buffer content format is bound to that selected format. In addition
>>>> +to the basic :ref:`format` ioctls, the :c:func:`VIDIOC_ENUM_FMT` ioctl must be
>>>> +supported as well.
>>>> +
>>>> +To use the :ref:`format` ioctls applications set the ``type`` field of the
>>>> +:c:type:`v4l2_format` structure to ``V4L2_BUF_TYPE_AUDIO_CAPTURE`` or to
>>>> +``V4L2_BUF_TYPE_AUDIO_OUTPUT``. Both drivers and applications must set the
>>>> +remainder of the :c:type:`v4l2_format` structure to 0.
>>>> +
>>>> +.. c:type:: v4l2_audio_format
>>>> +
>>>> +.. tabularcolumns:: |p{1.4cm}|p{2.4cm}|p{13.5cm}|
>>>> +
>>>> +.. flat-table:: struct v4l2_audio_format
>>>> +    :header-rows:  0
>>>> +    :stub-columns: 0
>>>> +    :widths:       1 1 2
>>>> +
>>>> +    * - __u32
>>>> +      - ``pixelformat``
>>>> +      - The sample format, set by the application. see :ref:`pixfmt-audio`
>>>
>>> pixelformat doesn't make any sense for audio: there are no pixels on a
>>> PCM stream. Please use call it, instead: `snd_pcm_format`, making it match
>>> the values for snd_pcm_format_t.
>>>
>>
>> +1
>>
>> FWIW v4l2_meta_format uses the name "dataformat".
>>
>> Actually, I just realized that the C code actually uses the name
>> "audioformat". Tbh., after reading the kerneldoc comment, my
>> subjective preference would be on "sample_format", since that's
>> exactly what it is.
>>
> Ok, I will change it to sampleformat.
> 
> Best Regards
> Shengjiu Wang
> 
>>> Yet, I would keep defining it as u32 (or u64?) instead of using a
>>> typedef int field there (snd_pcm_format_t), as the size of integer
>>> is different on 32 and 64 bit kernels.
>>
>> +1
>>
>> Best regards,
>> Tomasz

Patch

diff --git a/Documentation/userspace-api/media/v4l/buffer.rst b/Documentation/userspace-api/media/v4l/buffer.rst
index 52bbee81c080..a3754ca6f0d6 100644
--- a/Documentation/userspace-api/media/v4l/buffer.rst
+++ b/Documentation/userspace-api/media/v4l/buffer.rst
@@ -438,6 +438,12 @@  enum v4l2_buf_type
     * - ``V4L2_BUF_TYPE_META_OUTPUT``
       - 14
       - Buffer for metadata output, see :ref:`metadata`.
+    * - ``V4L2_BUF_TYPE_AUDIO_CAPTURE``
+      - 15
+      - Buffer for audio capture, see :ref:`audio`.
+    * - ``V4L2_BUF_TYPE_AUDIO_OUTPUT``
+      - 16
+      - Buffer for audio output, see :ref:`audio`.
 
 
 .. _buffer-flags:
diff --git a/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst b/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
new file mode 100644
index 000000000000..68faecfe3a02
--- /dev/null
+++ b/Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst
@@ -0,0 +1,71 @@ 
+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+
+.. _audiomem2mem:
+
+********************************
+Audio Memory-To-Memory Interface
+********************************
+
+An audio memory-to-memory device can compress, decompress, transform, or
+otherwise convert audio data from one format into another format, in memory.
+Such memory-to-memory devices set the ``V4L2_CAP_AUDIO_M2M`` capability.
+Examples of memory-to-memory devices are audio codecs, audio preprocessing,
+audio postprocessing.
+
+A memory-to-memory audio node supports both output (sending audio frames from
+memory to the hardware) and capture (receiving the processed audio frames
+from the hardware into memory) stream I/O. An application will have to
+setup the stream I/O for both sides and finally call
+:ref:`VIDIOC_STREAMON <VIDIOC_STREAMON>` for both capture and output to
+start the hardware.
+
+Memory-to-memory devices function as a shared resource: you can
+open the audio node multiple times, each application setting up their
+own properties that are local to the file handle, and each can use
+it independently from the others. The driver will arbitrate access to
+the hardware and reprogram it whenever another file handler gets access.
+
+Audio memory-to-memory devices are accessed through character device
+special files named ``/dev/v4l-audio``
+
+Querying Capabilities
+=====================
+
+Device nodes supporting the audio memory-to-memory interface set the
+``V4L2_CAP_AUDIO_M2M`` flag in the ``device_caps`` field of the
+:c:type:`v4l2_capability` structure returned by the :c:func:`VIDIOC_QUERYCAP`
+ioctl.
+
+Data Format Negotiation
+=======================
+
+The audio device uses the :ref:`format` ioctls to select the capture format.
+The audio buffer content format is bound to that selected format. In addition
+to the basic :ref:`format` ioctls, the :c:func:`VIDIOC_ENUM_FMT` ioctl must be
+supported as well.
+
+To use the :ref:`format` ioctls applications set the ``type`` field of the
+:c:type:`v4l2_format` structure to ``V4L2_BUF_TYPE_AUDIO_CAPTURE`` or to
+``V4L2_BUF_TYPE_AUDIO_OUTPUT``. Both drivers and applications must set the
+remainder of the :c:type:`v4l2_format` structure to 0.
+
+.. c:type:: v4l2_audio_format
+
+.. tabularcolumns:: |p{1.4cm}|p{2.4cm}|p{13.5cm}|
+
+.. flat-table:: struct v4l2_audio_format
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+    * - __u32
+      - ``pixelformat``
+      - The sample format, set by the application. see :ref:`pixfmt-audio`
+    * - __u32
+      - ``channels``
+      - The channel number, set by the application. channel number range is
+        [1, 32].
+    * - __u32
+      - ``buffersize``
+      - Maximum buffer size in bytes required for data. The value is set by the
+        driver.
diff --git a/Documentation/userspace-api/media/v4l/devices.rst b/Documentation/userspace-api/media/v4l/devices.rst
index 8bfbad65a9d4..758bd90f1c26 100644
--- a/Documentation/userspace-api/media/v4l/devices.rst
+++ b/Documentation/userspace-api/media/v4l/devices.rst
@@ -24,3 +24,4 @@  Interfaces
     dev-event
     dev-subdev
     dev-meta
+    dev-audio-mem2mem
diff --git a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
index 000c154b0f98..42deb07f4ff4 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
@@ -96,6 +96,8 @@  the ``mbus_code`` field is handled differently:
 	``V4L2_BUF_TYPE_VIDEO_OVERLAY``,
 	``V4L2_BUF_TYPE_SDR_CAPTURE``,
 	``V4L2_BUF_TYPE_SDR_OUTPUT``,
+	``V4L2_BUF_TYPE_AUDIO_CAPTURE``,
+	``V4L2_BUF_TYPE_AUDIO_OUTPUT``,
 	``V4L2_BUF_TYPE_META_CAPTURE`` and
 	``V4L2_BUF_TYPE_META_OUTPUT``.
 	See :c:type:`v4l2_buf_type`.
diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-fmt.rst b/Documentation/userspace-api/media/v4l/vidioc-g-fmt.rst
index 675c385e5aca..528fd9df41aa 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-g-fmt.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-g-fmt.rst
@@ -130,6 +130,10 @@  The format as returned by :ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>` must be identical
       - ``meta``
       - Definition of a metadata format, see :ref:`meta-formats`, used by
 	metadata capture devices.
+    * - struct :c:type:`v4l2_audio_format`
+      - ``audio``
+      - Definition of a audio data format, see :ref:`audiomem2mem`, used by
+        audio memory-to-memory devices
     * - __u8
       - ``raw_data``\ [200]
       - Place holder for future extensions.
diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
index da6d0b8e4c2c..e61152bb80d1 100644
--- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
+++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
@@ -29,6 +29,8 @@  replace symbol V4L2_FIELD_SEQ_TB :c:type:`v4l2_field`
 replace symbol V4L2_FIELD_TOP :c:type:`v4l2_field`
 
 # Documented enum v4l2_buf_type
+replace symbol V4L2_BUF_TYPE_AUDIO_CAPTURE :c:type:`v4l2_buf_type`
+replace symbol V4L2_BUF_TYPE_AUDIO_OUTPUT :c:type:`v4l2_buf_type`
 replace symbol V4L2_BUF_TYPE_META_CAPTURE :c:type:`v4l2_buf_type`
 replace symbol V4L2_BUF_TYPE_META_OUTPUT :c:type:`v4l2_buf_type`
 replace symbol V4L2_BUF_TYPE_SDR_CAPTURE :c:type:`v4l2_buf_type`
diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index 54d572c3b515..16ab204d15b0 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -791,6 +791,10 @@  int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
 	case V4L2_BUF_TYPE_META_OUTPUT:
 		requested_sizes[0] = f->fmt.meta.buffersize;
 		break;
+	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
+	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
+		requested_sizes[0] = f->fmt.audio.buffersize;
+		break;
 	default:
 		return -EINVAL;
 	}
diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index 8c07400bd280..5e94db8dfdae 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -101,6 +101,7 @@  struct v4l2_format32 {
 		struct v4l2_sliced_vbi_format	sliced;
 		struct v4l2_sdr_format	sdr;
 		struct v4l2_meta_format	meta;
+		struct v4l2_audio_format	audio;
 		__u8	raw_data[200];        /* user-defined */
 	} fmt;
 };
@@ -166,6 +167,10 @@  static int get_v4l2_format32(struct v4l2_format *p64,
 	case V4L2_BUF_TYPE_META_OUTPUT:
 		return copy_from_user(&p64->fmt.meta, &p32->fmt.meta,
 				      sizeof(p64->fmt.meta)) ? -EFAULT : 0;
+	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
+	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
+		return copy_from_user(&p64->fmt.audio, &p32->fmt.audio,
+				      sizeof(p64->fmt.audio)) ? -EFAULT : 0;
 	default:
 		return -EINVAL;
 	}
@@ -216,6 +221,10 @@  static int put_v4l2_format32(struct v4l2_format *p64,
 	case V4L2_BUF_TYPE_META_OUTPUT:
 		return copy_to_user(&p32->fmt.meta, &p64->fmt.meta,
 				    sizeof(p64->fmt.meta)) ? -EFAULT : 0;
+	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
+	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
+		return copy_to_user(&p32->fmt.audio, &p64->fmt.audio,
+				    sizeof(p64->fmt.audio)) ? -EFAULT : 0;
 	default:
 		return -EINVAL;
 	}
diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
index d13954bd31fd..bac008fcedc6 100644
--- a/drivers/media/v4l2-core/v4l2-dev.c
+++ b/drivers/media/v4l2-core/v4l2-dev.c
@@ -553,6 +553,7 @@  static void determine_valid_ioctls(struct video_device *vdev)
 	bool is_tch = vdev->vfl_type == VFL_TYPE_TOUCH;
 	bool is_meta = vdev->vfl_type == VFL_TYPE_VIDEO &&
 		       (vdev->device_caps & meta_caps);
+	bool is_audio = vdev->vfl_type == VFL_TYPE_AUDIO;
 	bool is_rx = vdev->vfl_dir != VFL_DIR_TX;
 	bool is_tx = vdev->vfl_dir != VFL_DIR_RX;
 	bool is_io_mc = vdev->device_caps & V4L2_CAP_IO_MC;
@@ -666,6 +667,19 @@  static void determine_valid_ioctls(struct video_device *vdev)
 		SET_VALID_IOCTL(ops, VIDIOC_S_FMT, vidioc_s_fmt_meta_out);
 		SET_VALID_IOCTL(ops, VIDIOC_TRY_FMT, vidioc_try_fmt_meta_out);
 	}
+	if (is_audio && is_rx) {
+		/* audio capture specific ioctls */
+		SET_VALID_IOCTL(ops, VIDIOC_ENUM_FMT, vidioc_enum_fmt_audio_cap);
+		SET_VALID_IOCTL(ops, VIDIOC_G_FMT, vidioc_g_fmt_audio_cap);
+		SET_VALID_IOCTL(ops, VIDIOC_S_FMT, vidioc_s_fmt_audio_cap);
+		SET_VALID_IOCTL(ops, VIDIOC_TRY_FMT, vidioc_try_fmt_audio_cap);
+	} else if (is_audio && is_tx) {
+		/* audio output specific ioctls */
+		SET_VALID_IOCTL(ops, VIDIOC_ENUM_FMT, vidioc_enum_fmt_audio_out);
+		SET_VALID_IOCTL(ops, VIDIOC_G_FMT, vidioc_g_fmt_audio_out);
+		SET_VALID_IOCTL(ops, VIDIOC_S_FMT, vidioc_s_fmt_audio_out);
+		SET_VALID_IOCTL(ops, VIDIOC_TRY_FMT, vidioc_try_fmt_audio_out);
+	}
 	if (is_vbi) {
 		/* vbi specific ioctls */
 		if ((is_rx && (ops->vidioc_g_fmt_vbi_cap ||
@@ -929,6 +943,9 @@  int __video_register_device(struct video_device *vdev,
 	case VFL_TYPE_TOUCH:
 		name_base = "v4l-touch";
 		break;
+	case VFL_TYPE_AUDIO:
+		name_base = "v4l-audio";
+		break;
 	default:
 		pr_err("%s called with unknown type: %d\n",
 		       __func__, type);
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 33076af4dfdb..e7be7c2f302d 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -188,6 +188,8 @@  const char *v4l2_type_names[] = {
 	[V4L2_BUF_TYPE_SDR_OUTPUT]         = "sdr-out",
 	[V4L2_BUF_TYPE_META_CAPTURE]       = "meta-cap",
 	[V4L2_BUF_TYPE_META_OUTPUT]	   = "meta-out",
+	[V4L2_BUF_TYPE_AUDIO_CAPTURE]      = "audio-cap",
+	[V4L2_BUF_TYPE_AUDIO_OUTPUT]	   = "audio-out",
 };
 EXPORT_SYMBOL(v4l2_type_names);
 
@@ -276,6 +278,7 @@  static void v4l_print_format(const void *arg, bool write_only)
 	const struct v4l2_sliced_vbi_format *sliced;
 	const struct v4l2_window *win;
 	const struct v4l2_meta_format *meta;
+	const struct v4l2_audio_format *audio;
 	u32 pixelformat;
 	u32 planes;
 	unsigned i;
@@ -346,6 +349,13 @@  static void v4l_print_format(const void *arg, bool write_only)
 		pr_cont(", dataformat=%p4cc, buffersize=%u\n",
 			&pixelformat, meta->buffersize);
 		break;
+	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
+	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
+		audio = &p->fmt.audio;
+		pixelformat = audio->audioformat;
+		pr_cont(", format=%p4cc, channels=%u, buffersize=%u\n",
+			&pixelformat, audio->channels, audio->buffersize);
+		break;
 	}
 }
 
@@ -927,6 +937,7 @@  static int check_fmt(struct file *file, enum v4l2_buf_type type)
 	bool is_tch = vfd->vfl_type == VFL_TYPE_TOUCH;
 	bool is_meta = vfd->vfl_type == VFL_TYPE_VIDEO &&
 		       (vfd->device_caps & meta_caps);
+	bool is_audio = vfd->vfl_type == VFL_TYPE_AUDIO;
 	bool is_rx = vfd->vfl_dir != VFL_DIR_TX;
 	bool is_tx = vfd->vfl_dir != VFL_DIR_RX;
 
@@ -992,6 +1003,14 @@  static int check_fmt(struct file *file, enum v4l2_buf_type type)
 		if (is_meta && is_tx && ops->vidioc_g_fmt_meta_out)
 			return 0;
 		break;
+	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
+		if (is_audio && is_rx && ops->vidioc_g_fmt_audio_cap)
+			return 0;
+		break;
+	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
+		if (is_audio && is_tx && ops->vidioc_g_fmt_audio_out)
+			return 0;
+		break;
 	default:
 		break;
 	}
@@ -1597,6 +1616,16 @@  static int v4l_enum_fmt(const struct v4l2_ioctl_ops *ops,
 			break;
 		ret = ops->vidioc_enum_fmt_meta_out(file, fh, arg);
 		break;
+	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
+		if (unlikely(!ops->vidioc_enum_fmt_audio_cap))
+			break;
+		ret = ops->vidioc_enum_fmt_audio_cap(file, fh, arg);
+		break;
+	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
+		if (unlikely(!ops->vidioc_enum_fmt_audio_out))
+			break;
+		ret = ops->vidioc_enum_fmt_audio_out(file, fh, arg);
+		break;
 	}
 	if (ret == 0)
 		v4l_fill_fmtdesc(p);
@@ -1673,6 +1702,10 @@  static int v4l_g_fmt(const struct v4l2_ioctl_ops *ops,
 		return ops->vidioc_g_fmt_meta_cap(file, fh, arg);
 	case V4L2_BUF_TYPE_META_OUTPUT:
 		return ops->vidioc_g_fmt_meta_out(file, fh, arg);
+	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
+		return ops->vidioc_g_fmt_audio_cap(file, fh, arg);
+	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
+		return ops->vidioc_g_fmt_audio_out(file, fh, arg);
 	}
 	return -EINVAL;
 }
@@ -1784,6 +1817,16 @@  static int v4l_s_fmt(const struct v4l2_ioctl_ops *ops,
 			break;
 		memset_after(p, 0, fmt.meta);
 		return ops->vidioc_s_fmt_meta_out(file, fh, arg);
+	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
+		if (unlikely(!ops->vidioc_s_fmt_audio_cap))
+			break;
+		memset_after(p, 0, fmt.audio);
+		return ops->vidioc_s_fmt_audio_cap(file, fh, arg);
+	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
+		if (unlikely(!ops->vidioc_s_fmt_audio_out))
+			break;
+		memset_after(p, 0, fmt.audio);
+		return ops->vidioc_s_fmt_audio_out(file, fh, arg);
 	}
 	return -EINVAL;
 }
@@ -1892,6 +1935,16 @@  static int v4l_try_fmt(const struct v4l2_ioctl_ops *ops,
 			break;
 		memset_after(p, 0, fmt.meta);
 		return ops->vidioc_try_fmt_meta_out(file, fh, arg);
+	case V4L2_BUF_TYPE_AUDIO_CAPTURE:
+		if (unlikely(!ops->vidioc_try_fmt_audio_cap))
+			break;
+		memset_after(p, 0, fmt.audio);
+		return ops->vidioc_try_fmt_audio_cap(file, fh, arg);
+	case V4L2_BUF_TYPE_AUDIO_OUTPUT:
+		if (unlikely(!ops->vidioc_try_fmt_audio_out))
+			break;
+		memset_after(p, 0, fmt.audio);
+		return ops->vidioc_try_fmt_audio_out(file, fh, arg);
 	}
 	return -EINVAL;
 }
diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h
index d82dfdbf6e58..82b63f82d43f 100644
--- a/include/media/v4l2-dev.h
+++ b/include/media/v4l2-dev.h
@@ -30,6 +30,7 @@ 
  * @VFL_TYPE_SUBDEV:	for V4L2 subdevices
  * @VFL_TYPE_SDR:	for Software Defined Radio tuners
  * @VFL_TYPE_TOUCH:	for touch sensors
+ * @VFL_TYPE_AUDIO:	for audio memory-to-memory devices
  * @VFL_TYPE_MAX:	number of VFL types, must always be last in the enum
  */
 enum vfl_devnode_type {
@@ -39,6 +40,7 @@  enum vfl_devnode_type {
 	VFL_TYPE_SUBDEV,
 	VFL_TYPE_SDR,
 	VFL_TYPE_TOUCH,
+	VFL_TYPE_AUDIO,
 	VFL_TYPE_MAX /* Shall be the last one */
 };
 
diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
index edb733f21604..f840cf740ce1 100644
--- a/include/media/v4l2-ioctl.h
+++ b/include/media/v4l2-ioctl.h
@@ -45,6 +45,12 @@  struct v4l2_fh;
  * @vidioc_enum_fmt_meta_out: pointer to the function that implements
  *	:ref:`VIDIOC_ENUM_FMT <vidioc_enum_fmt>` ioctl logic
  *	for metadata output
+ * @vidioc_enum_fmt_audio_cap: pointer to the function that implements
+ *	:ref:`VIDIOC_ENUM_FMT <vidioc_enum_fmt>` ioctl logic
+ *	for audio capture
+ * @vidioc_enum_fmt_audio_out: pointer to the function that implements
+ *	:ref:`VIDIOC_ENUM_FMT <vidioc_enum_fmt>` ioctl logic
+ *	for audio output
  * @vidioc_g_fmt_vid_cap: pointer to the function that implements
  *	:ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for video capture
  *	in single plane mode
@@ -79,6 +85,10 @@  struct v4l2_fh;
  *	:ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for metadata capture
  * @vidioc_g_fmt_meta_out: pointer to the function that implements
  *	:ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for metadata output
+ * @vidioc_g_fmt_audio_cap: pointer to the function that implements
+ *	:ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for audio capture
+ * @vidioc_g_fmt_audio_out: pointer to the function that implements
+ *	:ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for audio output
  * @vidioc_s_fmt_vid_cap: pointer to the function that implements
  *	:ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for video capture
  *	in single plane mode
@@ -113,6 +123,10 @@  struct v4l2_fh;
  *	:ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for metadata capture
  * @vidioc_s_fmt_meta_out: pointer to the function that implements
  *	:ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for metadata output
+ * @vidioc_s_fmt_audio_cap: pointer to the function that implements
+ *	:ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for audio capture
+ * @vidioc_s_fmt_audio_out: pointer to the function that implements
+ *	:ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for audio output
  * @vidioc_try_fmt_vid_cap: pointer to the function that implements
  *	:ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for video capture
  *	in single plane mode
@@ -149,6 +163,10 @@  struct v4l2_fh;
  *	:ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for metadata capture
  * @vidioc_try_fmt_meta_out: pointer to the function that implements
  *	:ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for metadata output
+ * @vidioc_try_fmt_audio_cap: pointer to the function that implements
+ *	:ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for audio capture
+ * @vidioc_try_fmt_audio_out: pointer to the function that implements
+ *	:ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for audio output
  * @vidioc_reqbufs: pointer to the function that implements
  *	:ref:`VIDIOC_REQBUFS <vidioc_reqbufs>` ioctl
  * @vidioc_querybuf: pointer to the function that implements
@@ -315,6 +333,10 @@  struct v4l2_ioctl_ops {
 					struct v4l2_fmtdesc *f);
 	int (*vidioc_enum_fmt_meta_out)(struct file *file, void *fh,
 					struct v4l2_fmtdesc *f);
+	int (*vidioc_enum_fmt_audio_cap)(struct file *file, void *fh,
+					 struct v4l2_fmtdesc *f);
+	int (*vidioc_enum_fmt_audio_out)(struct file *file, void *fh,
+					 struct v4l2_fmtdesc *f);
 
 	/* VIDIOC_G_FMT handlers */
 	int (*vidioc_g_fmt_vid_cap)(struct file *file, void *fh,
@@ -345,6 +367,10 @@  struct v4l2_ioctl_ops {
 				     struct v4l2_format *f);
 	int (*vidioc_g_fmt_meta_out)(struct file *file, void *fh,
 				     struct v4l2_format *f);
+	int (*vidioc_g_fmt_audio_cap)(struct file *file, void *fh,
+				      struct v4l2_format *f);
+	int (*vidioc_g_fmt_audio_out)(struct file *file, void *fh,
+				      struct v4l2_format *f);
 
 	/* VIDIOC_S_FMT handlers */
 	int (*vidioc_s_fmt_vid_cap)(struct file *file, void *fh,
@@ -375,6 +401,10 @@  struct v4l2_ioctl_ops {
 				     struct v4l2_format *f);
 	int (*vidioc_s_fmt_meta_out)(struct file *file, void *fh,
 				     struct v4l2_format *f);
+	int (*vidioc_s_fmt_audio_cap)(struct file *file, void *fh,
+				      struct v4l2_format *f);
+	int (*vidioc_s_fmt_audio_out)(struct file *file, void *fh,
+				      struct v4l2_format *f);
 
 	/* VIDIOC_TRY_FMT handlers */
 	int (*vidioc_try_fmt_vid_cap)(struct file *file, void *fh,
@@ -405,6 +435,10 @@  struct v4l2_ioctl_ops {
 				       struct v4l2_format *f);
 	int (*vidioc_try_fmt_meta_out)(struct file *file, void *fh,
 				       struct v4l2_format *f);
+	int (*vidioc_try_fmt_audio_cap)(struct file *file, void *fh,
+					struct v4l2_format *f);
+	int (*vidioc_try_fmt_audio_out)(struct file *file, void *fh,
+					struct v4l2_format *f);
 
 	/* Buffer handlers */
 	int (*vidioc_reqbufs)(struct file *file, void *fh,
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 6cd65969c2b5..57c82eb158f1 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -153,6 +153,8 @@  enum v4l2_buf_type {
 	V4L2_BUF_TYPE_SDR_OUTPUT           = 12,
 	V4L2_BUF_TYPE_META_CAPTURE         = 13,
 	V4L2_BUF_TYPE_META_OUTPUT	   = 14,
+	V4L2_BUF_TYPE_AUDIO_CAPTURE        = 15,
+	V4L2_BUF_TYPE_AUDIO_OUTPUT         = 16,
 	/* Deprecated, do not use */
 	V4L2_BUF_TYPE_PRIVATE              = 0x80,
 };
@@ -169,6 +171,7 @@  enum v4l2_buf_type {
 	 || (type) == V4L2_BUF_TYPE_VBI_OUTPUT			\
 	 || (type) == V4L2_BUF_TYPE_SLICED_VBI_OUTPUT		\
 	 || (type) == V4L2_BUF_TYPE_SDR_OUTPUT			\
+	 || (type) == V4L2_BUF_TYPE_AUDIO_OUTPUT		\
 	 || (type) == V4L2_BUF_TYPE_META_OUTPUT)
 
 #define V4L2_TYPE_IS_CAPTURE(type) (!V4L2_TYPE_IS_OUTPUT(type))
@@ -2423,6 +2426,18 @@  struct v4l2_meta_format {
 	__u32				buffersize;
 } __attribute__ ((packed));
 
+/**
+ * struct v4l2_audio_format - audio data format definition
+ * @audioformat:	little endian four character code (fourcc)
+ * @channels:		channel numbers
+ * @buffersize:		maximum size in bytes required for data
+ */
+struct v4l2_audio_format {
+	__u32				audioformat;
+	__u32				channels;
+	__u32				buffersize;
+} __attribute__ ((packed));
+
 /**
  * struct v4l2_format - stream data format
  * @type:	enum v4l2_buf_type; type of the data stream
@@ -2431,6 +2446,7 @@  struct v4l2_meta_format {
  * @win:	definition of an overlaid image
  * @vbi:	raw VBI capture or output parameters
  * @sliced:	sliced VBI capture or output parameters
+ * @audio:	definition of an audio format
  * @raw_data:	placeholder for future extensions and custom formats
  * @fmt:	union of @pix, @pix_mp, @win, @vbi, @sliced, @sdr, @meta
  *		and @raw_data
@@ -2445,6 +2461,7 @@  struct v4l2_format {
 		struct v4l2_sliced_vbi_format	sliced;  /* V4L2_BUF_TYPE_SLICED_VBI_CAPTURE */
 		struct v4l2_sdr_format		sdr;     /* V4L2_BUF_TYPE_SDR_CAPTURE */
 		struct v4l2_meta_format		meta;    /* V4L2_BUF_TYPE_META_CAPTURE */
+		struct v4l2_audio_format	audio;   /* V4L2_BUF_TYPE_AUDIO_CAPTURE */
 		__u8	raw_data[200];                   /* user-defined */
 	} fmt;
 };