Re: [RFC PATCH v2 4/7] media: v4l2: Add audio capture and output support

Shengjiu Wang
2023-08-01T09:49:19Z

On Fri, Jul 28, 2023 at 3:59 PM Tomasz Figa <tfiga@chromium.org> wrote:
>
> Hi Shengjiu,
>
> On Tue, Jul 25, 2023 at 02:12:17PM +0800, Shengjiu Wang 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/audioX".
> >
> > Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
> > ---
> > .../media/common/videobuf2/videobuf2-v4l2.c | 4 ++
> > drivers/media/v4l2-core/v4l2-dev.c | 17 ++++++
> > drivers/media/v4l2-core/v4l2-ioctl.c | 52 +++++++++++++++++++
> > include/media/v4l2-dev.h | 2 +
> > include/media/v4l2-ioctl.h | 34 ++++++++++++
> > include/uapi/linux/videodev2.h | 19 +++++++
> > 6 files changed, 128 insertions(+)
> >
>
> Thanks for the patch! Please check my comments inline.

Thanks for reviewing.

Sorry for sending again for using the plain text mode.

>
> > diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> > index c7a54d82a55e..12f2be2773a2 100644
> > --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
> > +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> > @@ -785,6 +785,10 @@ 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-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
> > index f81279492682..67484f4c6eaf 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;
> > @@ -664,6 +665,19 @@ 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 ||
> > @@ -927,6 +941,9 @@ int __video_register_device(struct video_device *vdev,
> > case VFL_TYPE_TOUCH:
> > name_base = "v4l-touch";
> > break;
> > + case VFL_TYPE_AUDIO:
> > + name_base = "audio";
>
> I think it was mentioned before that "audio" could be confusing. Wasn't
> there actually some other kind of /dev/audio device long ago?
>
> Seems like for touch, "v4l-touch" was introduced. Maybe it would also
> make sense to call it "v4l-audio" for audio?

Ok, will change to use "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 01ba27f2ef87..aa9d872bba8d 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 +349,12 @@ 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;
> > + pr_cont(", rate=%u, format=%u, channels=%u, buffersize=%u\n",
> > + audio->rate, audio->format, audio->channels, audio->buffersize);
> > + break;
> > }
> > }
> >
> > @@ -927,6 +936,7 @@ 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 +1002,14 @@ 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;
> > }
> > @@ -1594,6 +1612,16 @@ 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);
> > @@ -1670,6 +1698,10 @@ 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;
> > }
> > @@ -1781,6 +1813,16 @@ 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;
> > }
> > @@ -1889,6 +1931,16 @@ 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 e0a13505f88d..0924e6d1dab1 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 input/output 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 3af6a82d0cad..e5051410928a 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))
> > @@ -2415,6 +2418,20 @@ struct v4l2_meta_format {
> > __u32 buffersize;
> > } __attribute__ ((packed));
> >
> > +/**
> > + * struct v4l2_audio_format - audio data format definition
> > + * @rate: sample rate
> > + * @format: sample format
> > + * @channels: channel numbers
> > + * @buffersize: maximum size in bytes required for data
> > + */
> > +struct v4l2_audio_format {
> > + __u32 rate;
> > + __u32 format;
>
> What are the values for the rate and format fields? Since they are part
> of the UAPI, they need to be defined.
>

The range for sample rate is [5512, 768000].
The format is defined in include/uapi/sound/asound.h, they are
SNDRV_PCM_FORMAT_S8, SNDRV_PCM_FORMAT_U8, ...

Where should I put these info?

Best regards
Wang shengjiu

> Best regards,
> Tomasz
>
> > + __u32 channels;
> > + __u32 buffersize;
> > +} __attribute__ ((packed));
> > +
> > /**
> > * struct v4l2_format - stream data format
> > * @type: enum v4l2_buf_type; type of the data stream
> > @@ -2423,6 +2440,7 @@ 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
> > @@ -2437,6 +2455,7 @@ 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;
> > };
> > --
> > 2.34.1
> >