[RFC,v6,11/11] media: viaudm2m: add virtual driver for audio memory to memory

Commit Message

Shengjiu Wang Oct. 13, 2023, 8:31 a.m. UTC

Audio memory to memory virtual driver use video memory to memory
virtual driver vim2m.c as example. The main difference is
device type is VFL_TYPE_AUDIO and device cap type is V4L2_CAP_AUDIO_M2M.

The device_run function is a dummy function, which is simply
copy the data from input buffer to output buffer.

Signed-off-by: Shengjiu Wang <[e-mail]>
---
 drivers/media/test-drivers/Kconfig    |   9 +
 drivers/media/test-drivers/Makefile   |   1 +
 drivers/media/test-drivers/viaudm2m.c | 707 ++++++++++++++++++++++++++
 3 files changed, 717 insertions(+)
 create mode 100644 drivers/media/test-drivers/viaudm2m.c

Comments

Hans Verkuil Oct. 16, 2023, 2:08 p.m. UTC | #1

On 13/10/2023 10:31, Shengjiu Wang wrote:
> Audio memory to memory virtual driver use video memory to memory
> virtual driver vim2m.c as example. The main difference is
> device type is VFL_TYPE_AUDIO and device cap type is V4L2_CAP_AUDIO_M2M.
> 
> The device_run function is a dummy function, which is simply
> copy the data from input buffer to output buffer.
> 
> Signed-off-by: Shengjiu Wang <[e-mail]>
> ---
>  drivers/media/test-drivers/Kconfig    |   9 +
>  drivers/media/test-drivers/Makefile   |   1 +
>  drivers/media/test-drivers/viaudm2m.c | 707 ++++++++++++++++++++++++++
>  3 files changed, 717 insertions(+)
>  create mode 100644 drivers/media/test-drivers/viaudm2m.c
> 
> diff --git a/drivers/media/test-drivers/Kconfig b/drivers/media/test-drivers/Kconfig
> index 459b433e9fae..143d829e1b67 100644
> --- a/drivers/media/test-drivers/Kconfig
> +++ b/drivers/media/test-drivers/Kconfig
> @@ -17,6 +17,15 @@ config VIDEO_VIM2M
>  	  This is a virtual test device for the memory-to-memory driver
>  	  framework.
>  
> +config VIDEO_VIAUDM2M
> +	tristate "Virtual Memory-to-Memory Driver For Audio"

I think this is better:

VIDEO_VIM2M_AUDIO

and name the source: vim2m_audio.c.

> +	depends on VIDEO_DEV
> +	select VIDEOBUF2_VMALLOC
> +	select V4L2_MEM2MEM_DEV
> +	help
> +	  This is a virtual audio test device for the memory-to-memory driver
> +	  framework.
> +
>  source "drivers/media/test-drivers/vicodec/Kconfig"
>  source "drivers/media/test-drivers/vimc/Kconfig"
>  source "drivers/media/test-drivers/vivid/Kconfig"
> diff --git a/drivers/media/test-drivers/Makefile b/drivers/media/test-drivers/Makefile
> index 740714a4584d..a39d27eb53fa 100644
> --- a/drivers/media/test-drivers/Makefile
> +++ b/drivers/media/test-drivers/Makefile
> @@ -10,6 +10,7 @@ obj-$(CONFIG_DVB_VIDTV) += vidtv/
>  
>  obj-$(CONFIG_VIDEO_VICODEC) += vicodec/
>  obj-$(CONFIG_VIDEO_VIM2M) += vim2m.o
> +obj-$(CONFIG_VIDEO_VIAUDM2M) += viaudm2m.o
>  obj-$(CONFIG_VIDEO_VIMC) += vimc/
>  obj-$(CONFIG_VIDEO_VIVID) += vivid/
>  obj-$(CONFIG_VIDEO_VISL) += visl/
> diff --git a/drivers/media/test-drivers/viaudm2m.c b/drivers/media/test-drivers/viaudm2m.c
> new file mode 100644
> index 000000000000..5fefd616b6c8
> --- /dev/null
> +++ b/drivers/media/test-drivers/viaudm2m.c
> @@ -0,0 +1,707 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * A virtual v4l2-mem2mem example for audio device.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/delay.h>
> +#include <linux/fs.h>
> +#include <linux/sched.h>
> +#include <linux/slab.h>
> +
> +#include <linux/platform_device.h>
> +#include <media/v4l2-mem2mem.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-ioctl.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-event.h>
> +#include <media/videobuf2-vmalloc.h>
> +#include <sound/dmaengine_pcm.h>
> +
> +MODULE_DESCRIPTION("Virtual device for audio mem2mem testing");
> +MODULE_LICENSE("GPL");
> +MODULE_VERSION("0.1");

Drop this, rarely needed.

> +MODULE_ALIAS("audio_mem2mem_testdev");

Drop this as well. I'm not sure why it is in the original vim2m.c source.

> +
> +static unsigned int debug;
> +module_param(debug, uint, 0644);
> +MODULE_PARM_DESC(debug, "debug level");
> +
> +#define MEM2MEM_NAME "viaudm2m"

"vim2m-audio"

> +
> +#define dprintk(dev, lvl, fmt, arg...) \
> +	v4l2_dbg(lvl, debug, &(dev)->v4l2_dev, "%s: " fmt, __func__, ## arg)
> +
> +#define SAMPLE_NUM 4096
> +
> +static void audm2m_dev_release(struct device *dev)
> +{}
> +
> +static struct platform_device audm2m_pdev = {
> +	.name		= MEM2MEM_NAME,
> +	.dev.release	= audm2m_dev_release,
> +};
> +
> +struct audm2m_fmt {
> +	u32	fourcc;
> +	snd_pcm_format_t        format;

Same as for the previous driver: I think you can just drop this field and thus
the whole struct.

> +};
> +
> +static struct audm2m_fmt formats[] = {

And this is just a u32 array.

> +	{
> +		.fourcc = V4L2_AUDIO_FMT_S8,
> +	},
> +	{
> +		.fourcc = V4L2_AUDIO_FMT_S16_LE,
> +	},
> +	{
> +		.fourcc = V4L2_AUDIO_FMT_U16_LE,
> +	},
> +	{
> +		.fourcc = V4L2_AUDIO_FMT_S24_LE,
> +	},
> +	{
> +		.fourcc = V4L2_AUDIO_FMT_S24_3LE,
> +	},
> +	{
> +		.fourcc = V4L2_AUDIO_FMT_U24_LE,
> +	},
> +	{
> +		.fourcc = V4L2_AUDIO_FMT_U24_3LE,
> +	},
> +	{
> +		.fourcc = V4L2_AUDIO_FMT_S32_LE,
> +	},
> +	{
> +		.fourcc = V4L2_AUDIO_FMT_U32_LE,
> +	},
> +	{
> +		.fourcc = V4L2_AUDIO_FMT_S20_3LE,
> +	},
> +	{
> +		.fourcc = V4L2_AUDIO_FMT_U20_3LE,
> +	},
> +};
> +
> +#define NUM_FORMATS ARRAY_SIZE(formats)
> +
> +/* Per-queue, driver-specific private data */
> +struct audm2m_q_data {
> +	unsigned int		rate;
> +	unsigned int		channels;
> +	unsigned int		buffersize;
> +	struct audm2m_fmt	*fmt;
> +};
> +
> +enum {
> +	V4L2_M2M_SRC = 0,
> +	V4L2_M2M_DST = 1,
> +};
> +
> +static struct audm2m_fmt *find_format(u32 fourcc)
> +{
> +	struct audm2m_fmt *fmt;
> +	unsigned int k;
> +
> +	for (k = 0; k < NUM_FORMATS; k++) {
> +		fmt = &formats[k];
> +		if (fmt->fourcc == fourcc)
> +			break;
> +	}
> +
> +	if (k == NUM_FORMATS)
> +		return NULL;
> +
> +	formats[k].format = (__force snd_pcm_format_t)v4l2_fourcc_to_audfmt(formats[k].fourcc);
> +
> +	return &formats[k];
> +}
> +
> +struct audm2m_dev {
> +	struct v4l2_device	v4l2_dev;
> +	struct video_device	vfd;
> +
> +	struct mutex		dev_mutex;
> +
> +	struct v4l2_m2m_dev	*m2m_dev;
> +};
> +
> +struct audm2m_ctx {
> +	struct v4l2_fh		fh;
> +	struct audm2m_dev	*dev;
> +
> +	struct mutex		vb_mutex;
> +
> +	/* Source and destination queue data */
> +	struct audm2m_q_data   q_data[2];
> +};
> +
> +static inline struct audm2m_ctx *file2ctx(struct file *file)
> +{
> +	return container_of(file->private_data, struct audm2m_ctx, fh);
> +}
> +
> +static struct audm2m_q_data *get_q_data(struct audm2m_ctx *ctx,
> +					enum v4l2_buf_type type)
> +{
> +	if (type == V4L2_BUF_TYPE_AUDIO_OUTPUT)
> +		return &ctx->q_data[V4L2_M2M_SRC];
> +	return &ctx->q_data[V4L2_M2M_DST];
> +}
> +
> +static const char *type_name(enum v4l2_buf_type type)
> +{
> +	if (type == V4L2_BUF_TYPE_AUDIO_OUTPUT)
> +		return "Output";
> +	return "Capture";
> +}
> +
> +/*
> + * mem2mem callbacks
> + */
> +
> +/*
> + * device_run() - prepares and starts the device
> + */
> +static void device_run(void *priv)
> +{
> +	struct audm2m_ctx *ctx = priv;
> +	struct audm2m_dev *audm2m_dev;
> +	struct vb2_v4l2_buffer *src_buf, *dst_buf;
> +	struct audm2m_q_data *q_data_src, *q_data_dst;
> +	int src_size, dst_size;
> +
> +	audm2m_dev = ctx->dev;
> +
> +	q_data_src = get_q_data(ctx, V4L2_BUF_TYPE_AUDIO_OUTPUT);
> +	if (!q_data_src)
> +		return;
> +
> +	q_data_dst = get_q_data(ctx, V4L2_BUF_TYPE_AUDIO_CAPTURE);
> +	if (!q_data_dst)
> +		return;
> +
> +	src_buf = v4l2_m2m_next_src_buf(ctx->fh.m2m_ctx);
> +	dst_buf = v4l2_m2m_next_dst_buf(ctx->fh.m2m_ctx);
> +
> +	/* Process the conversion */
> +	src_size = vb2_get_plane_payload(&src_buf->vb2_buf, 0);
> +
> +	if (src_size > q_data_dst->buffersize)
> +		dst_size = q_data_dst->buffersize;
> +	else
> +		dst_size = src_size;
> +
> +	memcpy(vb2_plane_vaddr(&dst_buf->vb2_buf, 0),
> +	       vb2_plane_vaddr(&src_buf->vb2_buf, 0),
> +	       dst_size);
> +
> +	vb2_set_plane_payload(&dst_buf->vb2_buf, 0, dst_size);
> +
> +	src_buf = v4l2_m2m_src_buf_remove(ctx->fh.m2m_ctx);
> +	dst_buf = v4l2_m2m_dst_buf_remove(ctx->fh.m2m_ctx);
> +
> +	v4l2_m2m_buf_done(src_buf, VB2_BUF_STATE_DONE);
> +	v4l2_m2m_buf_done(dst_buf, VB2_BUF_STATE_DONE);
> +	v4l2_m2m_job_finish(audm2m_dev->m2m_dev, ctx->fh.m2m_ctx);
> +}
> +
> +static int audm2m_querycap(struct file *file, void *priv,
> +			   struct v4l2_capability *cap)
> +{
> +	strscpy(cap->driver, MEM2MEM_NAME, sizeof(cap->driver));
> +	strscpy(cap->card, MEM2MEM_NAME, sizeof(cap->card));
> +	snprintf(cap->bus_info, sizeof(cap->bus_info),
> +		 "platform:%s", MEM2MEM_NAME);
> +
> +	return 0;
> +}
> +
> +static int enum_fmt(struct v4l2_fmtdesc *f)
> +{
> +	int i, num;
> +	struct audm2m_fmt *fmt;
> +
> +	num = 0;
> +
> +	for (i = 0; i < NUM_FORMATS; ++i) {
> +		if (num == f->index)
> +			break;
> +		/*
> +		 * Correct type but haven't reached our index yet,
> +		 * just increment per-type index
> +		 */
> +		++num;
> +	}
> +
> +	if (i < NUM_FORMATS) {
> +		/* Format found */
> +		fmt = &formats[i];
> +		f->pixelformat = fmt->fourcc;
> +		return 0;
> +	}
> +
> +	/* Format not found */
> +	return -EINVAL;
> +}
> +
> +static int audm2m_enum_fmt_audio_cap(struct file *file, void *priv,
> +				     struct v4l2_fmtdesc *f)
> +{
> +	return enum_fmt(f);
> +}
> +
> +static int audm2m_enum_fmt_audio_out(struct file *file, void *priv,
> +				     struct v4l2_fmtdesc *f)
> +{
> +	return enum_fmt(f);
> +}
> +
> +static int audm2m_g_fmt(struct audm2m_ctx *ctx, struct v4l2_format *f)
> +{
> +	struct vb2_queue *vq;
> +	struct audm2m_q_data *q_data;
> +
> +	vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, f->type);
> +	if (!vq)
> +		return -EINVAL;
> +
> +	q_data = get_q_data(ctx, f->type);
> +	if (!q_data)
> +		return -EINVAL;
> +
> +	f->fmt.audio.audioformat = q_data->fmt->fourcc;
> +	f->fmt.audio.channels	= q_data->channels;
> +	f->fmt.audio.buffersize = q_data->buffersize;
> +
> +	return 0;
> +}
> +
> +static int audm2m_g_fmt_audio_out(struct file *file, void *priv,
> +				  struct v4l2_format *f)
> +{
> +	return audm2m_g_fmt(file2ctx(file), f);
> +}
> +
> +static int audm2m_g_fmt_audio_cap(struct file *file, void *priv,
> +				  struct v4l2_format *f)
> +{
> +	return audm2m_g_fmt(file2ctx(file), f);
> +}
> +
> +static int audm2m_try_fmt(struct v4l2_format *f, struct audm2m_fmt *fmt)
> +{
> +	if (f->fmt.audio.channels < 1)
> +		f->fmt.audio.channels = 1;
> +	else if (f->fmt.audio.channels > 8)
> +		f->fmt.audio.channels = 8;
> +
> +	f->fmt.audio.buffersize = f->fmt.audio.channels *
> +				  snd_pcm_format_physical_width(fmt->format) *
> +				  SAMPLE_NUM;
> +	return 0;
> +}
> +
> +static int audm2m_try_fmt_audio_cap(struct file *file, void *priv,
> +				    struct v4l2_format *f)
> +{
> +	struct audm2m_fmt *fmt;
> +
> +	fmt = find_format(f->fmt.audio.audioformat);
> +	if (!fmt) {
> +		f->fmt.audio.audioformat = formats[0].fourcc;
> +		fmt = find_format(f->fmt.audio.audioformat);
> +	}
> +
> +	return audm2m_try_fmt(f, fmt);
> +}
> +
> +static int audm2m_try_fmt_audio_out(struct file *file, void *priv,
> +				    struct v4l2_format *f)
> +{
> +	struct audm2m_fmt *fmt;
> +
> +	fmt = find_format(f->fmt.audio.audioformat);
> +	if (!fmt) {
> +		f->fmt.audio.audioformat = formats[0].fourcc;
> +		fmt = find_format(f->fmt.audio.audioformat);
> +	}
> +
> +	return audm2m_try_fmt(f, fmt);
> +}
> +
> +static int audm2m_s_fmt(struct audm2m_ctx *ctx, struct v4l2_format *f)
> +{
> +	struct audm2m_q_data *q_data;
> +	struct vb2_queue *vq;
> +
> +	vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, f->type);
> +	if (!vq)
> +		return -EINVAL;
> +
> +	q_data = get_q_data(ctx, f->type);
> +	if (!q_data)
> +		return -EINVAL;
> +
> +	if (vb2_is_busy(vq)) {
> +		v4l2_err(&ctx->dev->v4l2_dev, "%s queue busy\n", __func__);
> +		return -EBUSY;
> +	}
> +
> +	q_data->fmt	= find_format(f->fmt.audio.audioformat);
> +	q_data->channels = f->fmt.audio.channels;
> +	q_data->buffersize = q_data->channels *
> +			     snd_pcm_format_physical_width(q_data->fmt->format) *
> +			     SAMPLE_NUM;
> +
> +	dprintk(ctx->dev, 1,
> +		"Format for type %s: %d/%d, fmt: %c%c%c%c\n",
> +		type_name(f->type), q_data->rate,
> +		q_data->channels,
> +		(q_data->fmt->fourcc & 0xff),
> +		(q_data->fmt->fourcc >>  8) & 0xff,
> +		(q_data->fmt->fourcc >> 16) & 0xff,
> +		(q_data->fmt->fourcc >> 24) & 0xff);
> +
> +	return 0;
> +}
> +
> +static int audm2m_s_fmt_audio_cap(struct file *file, void *priv,
> +				  struct v4l2_format *f)
> +{
> +	int ret;
> +
> +	ret = audm2m_try_fmt_audio_cap(file, priv, f);
> +	if (ret)
> +		return ret;
> +
> +	return audm2m_s_fmt(file2ctx(file), f);
> +}
> +
> +static int audm2m_s_fmt_audio_out(struct file *file, void *priv,
> +				  struct v4l2_format *f)
> +{
> +	int ret;
> +
> +	ret = audm2m_try_fmt_audio_out(file, priv, f);
> +	if (ret)
> +		return ret;
> +
> +	return audm2m_s_fmt(file2ctx(file), f);
> +}
> +
> +static const struct v4l2_ioctl_ops audm2m_ioctl_ops = {
> +	.vidioc_querycap		= audm2m_querycap,
> +
> +	.vidioc_enum_fmt_audio_cap	= audm2m_enum_fmt_audio_cap,
> +	.vidioc_g_fmt_audio_cap		= audm2m_g_fmt_audio_cap,
> +	.vidioc_try_fmt_audio_cap	= audm2m_try_fmt_audio_cap,
> +	.vidioc_s_fmt_audio_cap		= audm2m_s_fmt_audio_cap,
> +
> +	.vidioc_enum_fmt_audio_out	= audm2m_enum_fmt_audio_out,
> +	.vidioc_g_fmt_audio_out		= audm2m_g_fmt_audio_out,
> +	.vidioc_try_fmt_audio_out	= audm2m_try_fmt_audio_out,
> +	.vidioc_s_fmt_audio_out		= audm2m_s_fmt_audio_out,
> +
> +	.vidioc_reqbufs			= v4l2_m2m_ioctl_reqbufs,
> +	.vidioc_querybuf		= v4l2_m2m_ioctl_querybuf,
> +	.vidioc_qbuf			= v4l2_m2m_ioctl_qbuf,
> +	.vidioc_dqbuf			= v4l2_m2m_ioctl_dqbuf,
> +	.vidioc_prepare_buf		= v4l2_m2m_ioctl_prepare_buf,
> +	.vidioc_create_bufs		= v4l2_m2m_ioctl_create_bufs,
> +	.vidioc_expbuf			= v4l2_m2m_ioctl_expbuf,
> +
> +	.vidioc_streamon		= v4l2_m2m_ioctl_streamon,
> +	.vidioc_streamoff		= v4l2_m2m_ioctl_streamoff,
> +
> +	.vidioc_subscribe_event		= v4l2_ctrl_subscribe_event,
> +	.vidioc_unsubscribe_event	= v4l2_event_unsubscribe,
> +};
> +
> +/*
> + * Queue operations
> + */
> +static int audm2m_queue_setup(struct vb2_queue *vq,
> +			      unsigned int *nbuffers,
> +			      unsigned int *nplanes,
> +			      unsigned int sizes[],
> +			      struct device *alloc_devs[])
> +{
> +	struct audm2m_ctx *ctx = vb2_get_drv_priv(vq);
> +	struct audm2m_q_data *q_data;
> +
> +	q_data = get_q_data(ctx, vq->type);
> +
> +	if (*nplanes)
> +		return sizes[0] < q_data->buffersize ? -EINVAL : 0;
> +
> +	*nplanes = 1;
> +	sizes[0] = q_data->buffersize;
> +
> +	dprintk(ctx->dev, 1, "%s: get %d buffer(s) of size %d each.\n",
> +		type_name(vq->type), *nplanes, sizes[0]);
> +
> +	return 0;
> +}
> +
> +static void audm2m_buf_queue(struct vb2_buffer *vb)
> +{
> +	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
> +	struct audm2m_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue);
> +
> +	v4l2_m2m_buf_queue(ctx->fh.m2m_ctx, vbuf);
> +}
> +
> +static void audm2m_stop_streaming(struct vb2_queue *q)
> +{
> +	struct audm2m_ctx *ctx = vb2_get_drv_priv(q);
> +	struct vb2_v4l2_buffer *vbuf;
> +
> +	for (;;) {
> +		if (V4L2_TYPE_IS_OUTPUT(q->type))
> +			vbuf = v4l2_m2m_src_buf_remove(ctx->fh.m2m_ctx);
> +		else
> +			vbuf = v4l2_m2m_dst_buf_remove(ctx->fh.m2m_ctx);
> +		if (!vbuf)
> +			return;
> +		v4l2_m2m_buf_done(vbuf, VB2_BUF_STATE_ERROR);
> +	}
> +}
> +
> +static const struct vb2_ops audm2m_qops = {
> +	.queue_setup	 = audm2m_queue_setup,
> +	.buf_queue	 = audm2m_buf_queue,
> +	.stop_streaming  = audm2m_stop_streaming,
> +	.wait_prepare	 = vb2_ops_wait_prepare,
> +	.wait_finish	 = vb2_ops_wait_finish,
> +};
> +
> +static int queue_init(void *priv, struct vb2_queue *src_vq,
> +		      struct vb2_queue *dst_vq)
> +{
> +	struct audm2m_ctx *ctx = priv;
> +	int ret;
> +
> +	src_vq->type = V4L2_BUF_TYPE_AUDIO_OUTPUT;
> +	src_vq->io_modes = VB2_MMAP | VB2_DMABUF;
> +	src_vq->drv_priv = ctx;
> +	src_vq->buf_struct_size = sizeof(struct v4l2_m2m_buffer);
> +	src_vq->ops = &audm2m_qops;
> +	src_vq->mem_ops = &vb2_vmalloc_memops;
> +	src_vq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
> +	src_vq->lock = &ctx->vb_mutex;
> +	src_vq->min_buffers_needed = 1;
> +
> +	ret = vb2_queue_init(src_vq);
> +	if (ret)
> +		return ret;
> +
> +	dst_vq->type = V4L2_BUF_TYPE_AUDIO_CAPTURE;
> +	dst_vq->io_modes = VB2_MMAP | VB2_DMABUF;
> +	dst_vq->drv_priv = ctx;
> +	dst_vq->buf_struct_size = sizeof(struct v4l2_m2m_buffer);
> +	dst_vq->ops = &audm2m_qops;
> +	dst_vq->mem_ops = &vb2_vmalloc_memops;
> +	dst_vq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
> +	dst_vq->lock = &ctx->vb_mutex;
> +	dst_vq->min_buffers_needed = 1;
> +
> +	return vb2_queue_init(dst_vq);
> +}
> +
> +/*
> + * File operations
> + */
> +static int audm2m_open(struct file *file)
> +{
> +	struct audm2m_dev *dev = video_drvdata(file);
> +	struct audm2m_ctx *ctx = NULL;
> +	int width;
> +	int rc = 0;
> +
> +	if (mutex_lock_interruptible(&dev->dev_mutex))
> +		return -ERESTARTSYS;
> +	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
> +	if (!ctx) {
> +		rc = -ENOMEM;
> +		goto open_unlock;
> +	}
> +
> +	v4l2_fh_init(&ctx->fh, video_devdata(file));
> +	file->private_data = &ctx->fh;
> +	ctx->dev = dev;
> +
> +	ctx->q_data[V4L2_M2M_SRC].fmt = &formats[0];
> +	ctx->q_data[V4L2_M2M_SRC].rate = 8000;
> +	ctx->q_data[V4L2_M2M_SRC].channels = 2;
> +
> +	/* Fix to 4096 samples */
> +	width = snd_pcm_format_physical_width(formats[0].format);
> +	ctx->q_data[V4L2_M2M_SRC].buffersize = SAMPLE_NUM * 2 * width;
> +	ctx->q_data[V4L2_M2M_DST] = ctx->q_data[V4L2_M2M_SRC];
> +
> +	ctx->fh.m2m_ctx = v4l2_m2m_ctx_init(dev->m2m_dev, ctx, &queue_init);
> +
> +	mutex_init(&ctx->vb_mutex);
> +
> +	if (IS_ERR(ctx->fh.m2m_ctx)) {
> +		rc = PTR_ERR(ctx->fh.m2m_ctx);
> +
> +		v4l2_fh_exit(&ctx->fh);
> +		kfree(ctx);
> +		goto open_unlock;
> +	}
> +
> +	v4l2_fh_add(&ctx->fh);
> +
> +	dprintk(dev, 1, "Created instance: %p, m2m_ctx: %p\n",
> +		ctx, ctx->fh.m2m_ctx);
> +
> +open_unlock:
> +	mutex_unlock(&dev->dev_mutex);
> +	return rc;
> +}
> +
> +static int audm2m_release(struct file *file)
> +{
> +	struct audm2m_dev *dev = video_drvdata(file);
> +	struct audm2m_ctx *ctx = file2ctx(file);
> +
> +	dprintk(dev, 1, "Releasing instance %p\n", ctx);
> +
> +	v4l2_fh_del(&ctx->fh);
> +	v4l2_fh_exit(&ctx->fh);
> +	mutex_lock(&dev->dev_mutex);
> +	v4l2_m2m_ctx_release(ctx->fh.m2m_ctx);
> +	mutex_unlock(&dev->dev_mutex);
> +	kfree(ctx);
> +
> +	return 0;
> +}
> +
> +static void audm2m_device_release(struct video_device *vdev)
> +{
> +	struct audm2m_dev *dev = container_of(vdev, struct audm2m_dev, vfd);
> +
> +	v4l2_device_unregister(&dev->v4l2_dev);
> +	v4l2_m2m_release(dev->m2m_dev);
> +
> +	kfree(dev);
> +}
> +
> +static const struct v4l2_file_operations audm2m_fops = {
> +	.owner		= THIS_MODULE,
> +	.open		= audm2m_open,
> +	.release	= audm2m_release,
> +	.poll		= v4l2_m2m_fop_poll,
> +	.unlocked_ioctl	= video_ioctl2,
> +	.mmap		= v4l2_m2m_fop_mmap,
> +};
> +
> +static const struct video_device audm2m_videodev = {
> +	.name		= MEM2MEM_NAME,
> +	.vfl_dir	= VFL_DIR_M2M,
> +	.fops		= &audm2m_fops,
> +	.ioctl_ops	= &audm2m_ioctl_ops,
> +	.minor		= -1,
> +	.release	= audm2m_device_release,
> +	.device_caps	= V4L2_CAP_AUDIO_M2M | V4L2_CAP_STREAMING,
> +};
> +
> +static const struct v4l2_m2m_ops m2m_ops = {
> +	.device_run	= device_run,
> +};
> +
> +static int audm2m_probe(struct platform_device *pdev)
> +{
> +	struct audm2m_dev *dev;
> +	struct video_device *vfd;
> +	int ret;
> +
> +	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
> +	if (!dev)
> +		return -ENOMEM;
> +
> +	ret = v4l2_device_register(&pdev->dev, &dev->v4l2_dev);
> +	if (ret)
> +		goto error_free;
> +
> +	mutex_init(&dev->dev_mutex);
> +
> +	dev->vfd = audm2m_videodev;
> +	vfd = &dev->vfd;
> +	vfd->lock = &dev->dev_mutex;
> +	vfd->v4l2_dev = &dev->v4l2_dev;
> +
> +	video_set_drvdata(vfd, dev);
> +	v4l2_info(&dev->v4l2_dev,
> +		  "Device registered as /dev/v4l-audio%d\n", vfd->num);
> +
> +	platform_set_drvdata(pdev, dev);
> +
> +	dev->m2m_dev = v4l2_m2m_init(&m2m_ops);
> +	if (IS_ERR(dev->m2m_dev)) {
> +		v4l2_err(&dev->v4l2_dev, "Failed to init mem2mem device\n");
> +		ret = PTR_ERR(dev->m2m_dev);
> +		dev->m2m_dev = NULL;
> +		goto error_dev;
> +	}
> +
> +	ret = video_register_device(vfd, VFL_TYPE_AUDIO, 0);
> +	if (ret) {
> +		v4l2_err(&dev->v4l2_dev, "Failed to register video device\n");
> +		goto error_m2m;
> +	}
> +
> +	return 0;
> +
> +error_m2m:
> +	v4l2_m2m_release(dev->m2m_dev);
> +error_dev:
> +	v4l2_device_unregister(&dev->v4l2_dev);
> +error_free:
> +	kfree(dev);
> +
> +	return ret;
> +}
> +
> +static void audm2m_remove(struct platform_device *pdev)
> +{
> +	struct audm2m_dev *dev = platform_get_drvdata(pdev);
> +
> +	v4l2_info(&dev->v4l2_dev, "Removing " MEM2MEM_NAME);
> +
> +	video_unregister_device(&dev->vfd);
> +}
> +
> +static struct platform_driver audm2m_pdrv = {
> +	.probe		= audm2m_probe,
> +	.remove_new	= audm2m_remove,
> +	.driver		= {
> +		.name	= MEM2MEM_NAME,
> +	},
> +};
> +
> +static void __exit audm2m_exit(void)
> +{
> +	platform_driver_unregister(&audm2m_pdrv);
> +	platform_device_unregister(&audm2m_pdev);
> +}
> +
> +static int __init audm2m_init(void)
> +{
> +	int ret;
> +
> +	ret = platform_device_register(&audm2m_pdev);
> +	if (ret)
> +		return ret;
> +
> +	ret = platform_driver_register(&audm2m_pdrv);
> +	if (ret)
> +		platform_device_unregister(&audm2m_pdev);
> +
> +	return ret;
> +}
> +
> +module_init(audm2m_init);
> +module_exit(audm2m_exit);

Regards,

	Hans

Patch

diff --git a/drivers/media/test-drivers/Kconfig b/drivers/media/test-drivers/Kconfig
index 459b433e9fae..143d829e1b67 100644
--- a/drivers/media/test-drivers/Kconfig
+++ b/drivers/media/test-drivers/Kconfig
@@ -17,6 +17,15 @@  config VIDEO_VIM2M
 	  This is a virtual test device for the memory-to-memory driver
 	  framework.
 
+config VIDEO_VIAUDM2M
+	tristate "Virtual Memory-to-Memory Driver For Audio"
+	depends on VIDEO_DEV
+	select VIDEOBUF2_VMALLOC
+	select V4L2_MEM2MEM_DEV
+	help
+	  This is a virtual audio test device for the memory-to-memory driver
+	  framework.
+
 source "drivers/media/test-drivers/vicodec/Kconfig"
 source "drivers/media/test-drivers/vimc/Kconfig"
 source "drivers/media/test-drivers/vivid/Kconfig"
diff --git a/drivers/media/test-drivers/Makefile b/drivers/media/test-drivers/Makefile
index 740714a4584d..a39d27eb53fa 100644
--- a/drivers/media/test-drivers/Makefile
+++ b/drivers/media/test-drivers/Makefile
@@ -10,6 +10,7 @@  obj-$(CONFIG_DVB_VIDTV) += vidtv/
 
 obj-$(CONFIG_VIDEO_VICODEC) += vicodec/
 obj-$(CONFIG_VIDEO_VIM2M) += vim2m.o
+obj-$(CONFIG_VIDEO_VIAUDM2M) += viaudm2m.o
 obj-$(CONFIG_VIDEO_VIMC) += vimc/
 obj-$(CONFIG_VIDEO_VIVID) += vivid/
 obj-$(CONFIG_VIDEO_VISL) += visl/
diff --git a/drivers/media/test-drivers/viaudm2m.c b/drivers/media/test-drivers/viaudm2m.c
new file mode 100644
index 000000000000..5fefd616b6c8
--- /dev/null
+++ b/drivers/media/test-drivers/viaudm2m.c
@@ -0,0 +1,707 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * A virtual v4l2-mem2mem example for audio device.
+ */
+
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#include <linux/platform_device.h>
+#include <media/v4l2-mem2mem.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-ioctl.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-event.h>
+#include <media/videobuf2-vmalloc.h>
+#include <sound/dmaengine_pcm.h>
+
+MODULE_DESCRIPTION("Virtual device for audio mem2mem testing");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("0.1");
+MODULE_ALIAS("audio_mem2mem_testdev");
+
+static unsigned int debug;
+module_param(debug, uint, 0644);
+MODULE_PARM_DESC(debug, "debug level");
+
+#define MEM2MEM_NAME "viaudm2m"
+
+#define dprintk(dev, lvl, fmt, arg...) \
+	v4l2_dbg(lvl, debug, &(dev)->v4l2_dev, "%s: " fmt, __func__, ## arg)
+
+#define SAMPLE_NUM 4096
+
+static void audm2m_dev_release(struct device *dev)
+{}
+
+static struct platform_device audm2m_pdev = {
+	.name		= MEM2MEM_NAME,
+	.dev.release	= audm2m_dev_release,
+};
+
+struct audm2m_fmt {
+	u32	fourcc;
+	snd_pcm_format_t        format;
+};
+
+static struct audm2m_fmt formats[] = {
+	{
+		.fourcc = V4L2_AUDIO_FMT_S8,
+	},
+	{
+		.fourcc = V4L2_AUDIO_FMT_S16_LE,
+	},
+	{
+		.fourcc = V4L2_AUDIO_FMT_U16_LE,
+	},
+	{
+		.fourcc = V4L2_AUDIO_FMT_S24_LE,
+	},
+	{
+		.fourcc = V4L2_AUDIO_FMT_S24_3LE,
+	},
+	{
+		.fourcc = V4L2_AUDIO_FMT_U24_LE,
+	},
+	{
+		.fourcc = V4L2_AUDIO_FMT_U24_3LE,
+	},
+	{
+		.fourcc = V4L2_AUDIO_FMT_S32_LE,
+	},
+	{
+		.fourcc = V4L2_AUDIO_FMT_U32_LE,
+	},
+	{
+		.fourcc = V4L2_AUDIO_FMT_S20_3LE,
+	},
+	{
+		.fourcc = V4L2_AUDIO_FMT_U20_3LE,
+	},
+};
+
+#define NUM_FORMATS ARRAY_SIZE(formats)
+
+/* Per-queue, driver-specific private data */
+struct audm2m_q_data {
+	unsigned int		rate;
+	unsigned int		channels;
+	unsigned int		buffersize;
+	struct audm2m_fmt	*fmt;
+};
+
+enum {
+	V4L2_M2M_SRC = 0,
+	V4L2_M2M_DST = 1,
+};
+
+static struct audm2m_fmt *find_format(u32 fourcc)
+{
+	struct audm2m_fmt *fmt;
+	unsigned int k;
+
+	for (k = 0; k < NUM_FORMATS; k++) {
+		fmt = &formats[k];
+		if (fmt->fourcc == fourcc)
+			break;
+	}
+
+	if (k == NUM_FORMATS)
+		return NULL;
+
+	formats[k].format = (__force snd_pcm_format_t)v4l2_fourcc_to_audfmt(formats[k].fourcc);
+
+	return &formats[k];
+}
+
+struct audm2m_dev {
+	struct v4l2_device	v4l2_dev;
+	struct video_device	vfd;
+
+	struct mutex		dev_mutex;
+
+	struct v4l2_m2m_dev	*m2m_dev;
+};
+
+struct audm2m_ctx {
+	struct v4l2_fh		fh;
+	struct audm2m_dev	*dev;
+
+	struct mutex		vb_mutex;
+
+	/* Source and destination queue data */
+	struct audm2m_q_data   q_data[2];
+};
+
+static inline struct audm2m_ctx *file2ctx(struct file *file)
+{
+	return container_of(file->private_data, struct audm2m_ctx, fh);
+}
+
+static struct audm2m_q_data *get_q_data(struct audm2m_ctx *ctx,
+					enum v4l2_buf_type type)
+{
+	if (type == V4L2_BUF_TYPE_AUDIO_OUTPUT)
+		return &ctx->q_data[V4L2_M2M_SRC];
+	return &ctx->q_data[V4L2_M2M_DST];
+}
+
+static const char *type_name(enum v4l2_buf_type type)
+{
+	if (type == V4L2_BUF_TYPE_AUDIO_OUTPUT)
+		return "Output";
+	return "Capture";
+}
+
+/*
+ * mem2mem callbacks
+ */
+
+/*
+ * device_run() - prepares and starts the device
+ */
+static void device_run(void *priv)
+{
+	struct audm2m_ctx *ctx = priv;
+	struct audm2m_dev *audm2m_dev;
+	struct vb2_v4l2_buffer *src_buf, *dst_buf;
+	struct audm2m_q_data *q_data_src, *q_data_dst;
+	int src_size, dst_size;
+
+	audm2m_dev = ctx->dev;
+
+	q_data_src = get_q_data(ctx, V4L2_BUF_TYPE_AUDIO_OUTPUT);
+	if (!q_data_src)
+		return;
+
+	q_data_dst = get_q_data(ctx, V4L2_BUF_TYPE_AUDIO_CAPTURE);
+	if (!q_data_dst)
+		return;
+
+	src_buf = v4l2_m2m_next_src_buf(ctx->fh.m2m_ctx);
+	dst_buf = v4l2_m2m_next_dst_buf(ctx->fh.m2m_ctx);
+
+	/* Process the conversion */
+	src_size = vb2_get_plane_payload(&src_buf->vb2_buf, 0);
+
+	if (src_size > q_data_dst->buffersize)
+		dst_size = q_data_dst->buffersize;
+	else
+		dst_size = src_size;
+
+	memcpy(vb2_plane_vaddr(&dst_buf->vb2_buf, 0),
+	       vb2_plane_vaddr(&src_buf->vb2_buf, 0),
+	       dst_size);
+
+	vb2_set_plane_payload(&dst_buf->vb2_buf, 0, dst_size);
+
+	src_buf = v4l2_m2m_src_buf_remove(ctx->fh.m2m_ctx);
+	dst_buf = v4l2_m2m_dst_buf_remove(ctx->fh.m2m_ctx);
+
+	v4l2_m2m_buf_done(src_buf, VB2_BUF_STATE_DONE);
+	v4l2_m2m_buf_done(dst_buf, VB2_BUF_STATE_DONE);
+	v4l2_m2m_job_finish(audm2m_dev->m2m_dev, ctx->fh.m2m_ctx);
+}
+
+static int audm2m_querycap(struct file *file, void *priv,
+			   struct v4l2_capability *cap)
+{
+	strscpy(cap->driver, MEM2MEM_NAME, sizeof(cap->driver));
+	strscpy(cap->card, MEM2MEM_NAME, sizeof(cap->card));
+	snprintf(cap->bus_info, sizeof(cap->bus_info),
+		 "platform:%s", MEM2MEM_NAME);
+
+	return 0;
+}
+
+static int enum_fmt(struct v4l2_fmtdesc *f)
+{
+	int i, num;
+	struct audm2m_fmt *fmt;
+
+	num = 0;
+
+	for (i = 0; i < NUM_FORMATS; ++i) {
+		if (num == f->index)
+			break;
+		/*
+		 * Correct type but haven't reached our index yet,
+		 * just increment per-type index
+		 */
+		++num;
+	}
+
+	if (i < NUM_FORMATS) {
+		/* Format found */
+		fmt = &formats[i];
+		f->pixelformat = fmt->fourcc;
+		return 0;
+	}
+
+	/* Format not found */
+	return -EINVAL;
+}
+
+static int audm2m_enum_fmt_audio_cap(struct file *file, void *priv,
+				     struct v4l2_fmtdesc *f)
+{
+	return enum_fmt(f);
+}
+
+static int audm2m_enum_fmt_audio_out(struct file *file, void *priv,
+				     struct v4l2_fmtdesc *f)
+{
+	return enum_fmt(f);
+}
+
+static int audm2m_g_fmt(struct audm2m_ctx *ctx, struct v4l2_format *f)
+{
+	struct vb2_queue *vq;
+	struct audm2m_q_data *q_data;
+
+	vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, f->type);
+	if (!vq)
+		return -EINVAL;
+
+	q_data = get_q_data(ctx, f->type);
+	if (!q_data)
+		return -EINVAL;
+
+	f->fmt.audio.audioformat = q_data->fmt->fourcc;
+	f->fmt.audio.channels	= q_data->channels;
+	f->fmt.audio.buffersize = q_data->buffersize;
+
+	return 0;
+}
+
+static int audm2m_g_fmt_audio_out(struct file *file, void *priv,
+				  struct v4l2_format *f)
+{
+	return audm2m_g_fmt(file2ctx(file), f);
+}
+
+static int audm2m_g_fmt_audio_cap(struct file *file, void *priv,
+				  struct v4l2_format *f)
+{
+	return audm2m_g_fmt(file2ctx(file), f);
+}
+
+static int audm2m_try_fmt(struct v4l2_format *f, struct audm2m_fmt *fmt)
+{
+	if (f->fmt.audio.channels < 1)
+		f->fmt.audio.channels = 1;
+	else if (f->fmt.audio.channels > 8)
+		f->fmt.audio.channels = 8;
+
+	f->fmt.audio.buffersize = f->fmt.audio.channels *
+				  snd_pcm_format_physical_width(fmt->format) *
+				  SAMPLE_NUM;
+	return 0;
+}
+
+static int audm2m_try_fmt_audio_cap(struct file *file, void *priv,
+				    struct v4l2_format *f)
+{
+	struct audm2m_fmt *fmt;
+
+	fmt = find_format(f->fmt.audio.audioformat);
+	if (!fmt) {
+		f->fmt.audio.audioformat = formats[0].fourcc;
+		fmt = find_format(f->fmt.audio.audioformat);
+	}
+
+	return audm2m_try_fmt(f, fmt);
+}
+
+static int audm2m_try_fmt_audio_out(struct file *file, void *priv,
+				    struct v4l2_format *f)
+{
+	struct audm2m_fmt *fmt;
+
+	fmt = find_format(f->fmt.audio.audioformat);
+	if (!fmt) {
+		f->fmt.audio.audioformat = formats[0].fourcc;
+		fmt = find_format(f->fmt.audio.audioformat);
+	}
+
+	return audm2m_try_fmt(f, fmt);
+}
+
+static int audm2m_s_fmt(struct audm2m_ctx *ctx, struct v4l2_format *f)
+{
+	struct audm2m_q_data *q_data;
+	struct vb2_queue *vq;
+
+	vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, f->type);
+	if (!vq)
+		return -EINVAL;
+
+	q_data = get_q_data(ctx, f->type);
+	if (!q_data)
+		return -EINVAL;
+
+	if (vb2_is_busy(vq)) {
+		v4l2_err(&ctx->dev->v4l2_dev, "%s queue busy\n", __func__);
+		return -EBUSY;
+	}
+
+	q_data->fmt	= find_format(f->fmt.audio.audioformat);
+	q_data->channels = f->fmt.audio.channels;
+	q_data->buffersize = q_data->channels *
+			     snd_pcm_format_physical_width(q_data->fmt->format) *
+			     SAMPLE_NUM;
+
+	dprintk(ctx->dev, 1,
+		"Format for type %s: %d/%d, fmt: %c%c%c%c\n",
+		type_name(f->type), q_data->rate,
+		q_data->channels,
+		(q_data->fmt->fourcc & 0xff),
+		(q_data->fmt->fourcc >>  8) & 0xff,
+		(q_data->fmt->fourcc >> 16) & 0xff,
+		(q_data->fmt->fourcc >> 24) & 0xff);
+
+	return 0;
+}
+
+static int audm2m_s_fmt_audio_cap(struct file *file, void *priv,
+				  struct v4l2_format *f)
+{
+	int ret;
+
+	ret = audm2m_try_fmt_audio_cap(file, priv, f);
+	if (ret)
+		return ret;
+
+	return audm2m_s_fmt(file2ctx(file), f);
+}
+
+static int audm2m_s_fmt_audio_out(struct file *file, void *priv,
+				  struct v4l2_format *f)
+{
+	int ret;
+
+	ret = audm2m_try_fmt_audio_out(file, priv, f);
+	if (ret)
+		return ret;
+
+	return audm2m_s_fmt(file2ctx(file), f);
+}
+
+static const struct v4l2_ioctl_ops audm2m_ioctl_ops = {
+	.vidioc_querycap		= audm2m_querycap,
+
+	.vidioc_enum_fmt_audio_cap	= audm2m_enum_fmt_audio_cap,
+	.vidioc_g_fmt_audio_cap		= audm2m_g_fmt_audio_cap,
+	.vidioc_try_fmt_audio_cap	= audm2m_try_fmt_audio_cap,
+	.vidioc_s_fmt_audio_cap		= audm2m_s_fmt_audio_cap,
+
+	.vidioc_enum_fmt_audio_out	= audm2m_enum_fmt_audio_out,
+	.vidioc_g_fmt_audio_out		= audm2m_g_fmt_audio_out,
+	.vidioc_try_fmt_audio_out	= audm2m_try_fmt_audio_out,
+	.vidioc_s_fmt_audio_out		= audm2m_s_fmt_audio_out,
+
+	.vidioc_reqbufs			= v4l2_m2m_ioctl_reqbufs,
+	.vidioc_querybuf		= v4l2_m2m_ioctl_querybuf,
+	.vidioc_qbuf			= v4l2_m2m_ioctl_qbuf,
+	.vidioc_dqbuf			= v4l2_m2m_ioctl_dqbuf,
+	.vidioc_prepare_buf		= v4l2_m2m_ioctl_prepare_buf,
+	.vidioc_create_bufs		= v4l2_m2m_ioctl_create_bufs,
+	.vidioc_expbuf			= v4l2_m2m_ioctl_expbuf,
+
+	.vidioc_streamon		= v4l2_m2m_ioctl_streamon,
+	.vidioc_streamoff		= v4l2_m2m_ioctl_streamoff,
+
+	.vidioc_subscribe_event		= v4l2_ctrl_subscribe_event,
+	.vidioc_unsubscribe_event	= v4l2_event_unsubscribe,
+};
+
+/*
+ * Queue operations
+ */
+static int audm2m_queue_setup(struct vb2_queue *vq,
+			      unsigned int *nbuffers,
+			      unsigned int *nplanes,
+			      unsigned int sizes[],
+			      struct device *alloc_devs[])
+{
+	struct audm2m_ctx *ctx = vb2_get_drv_priv(vq);
+	struct audm2m_q_data *q_data;
+
+	q_data = get_q_data(ctx, vq->type);
+
+	if (*nplanes)
+		return sizes[0] < q_data->buffersize ? -EINVAL : 0;
+
+	*nplanes = 1;
+	sizes[0] = q_data->buffersize;
+
+	dprintk(ctx->dev, 1, "%s: get %d buffer(s) of size %d each.\n",
+		type_name(vq->type), *nplanes, sizes[0]);
+
+	return 0;
+}
+
+static void audm2m_buf_queue(struct vb2_buffer *vb)
+{
+	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
+	struct audm2m_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue);
+
+	v4l2_m2m_buf_queue(ctx->fh.m2m_ctx, vbuf);
+}
+
+static void audm2m_stop_streaming(struct vb2_queue *q)
+{
+	struct audm2m_ctx *ctx = vb2_get_drv_priv(q);
+	struct vb2_v4l2_buffer *vbuf;
+
+	for (;;) {
+		if (V4L2_TYPE_IS_OUTPUT(q->type))
+			vbuf = v4l2_m2m_src_buf_remove(ctx->fh.m2m_ctx);
+		else
+			vbuf = v4l2_m2m_dst_buf_remove(ctx->fh.m2m_ctx);
+		if (!vbuf)
+			return;
+		v4l2_m2m_buf_done(vbuf, VB2_BUF_STATE_ERROR);
+	}
+}
+
+static const struct vb2_ops audm2m_qops = {
+	.queue_setup	 = audm2m_queue_setup,
+	.buf_queue	 = audm2m_buf_queue,
+	.stop_streaming  = audm2m_stop_streaming,
+	.wait_prepare	 = vb2_ops_wait_prepare,
+	.wait_finish	 = vb2_ops_wait_finish,
+};
+
+static int queue_init(void *priv, struct vb2_queue *src_vq,
+		      struct vb2_queue *dst_vq)
+{
+	struct audm2m_ctx *ctx = priv;
+	int ret;
+
+	src_vq->type = V4L2_BUF_TYPE_AUDIO_OUTPUT;
+	src_vq->io_modes = VB2_MMAP | VB2_DMABUF;
+	src_vq->drv_priv = ctx;
+	src_vq->buf_struct_size = sizeof(struct v4l2_m2m_buffer);
+	src_vq->ops = &audm2m_qops;
+	src_vq->mem_ops = &vb2_vmalloc_memops;
+	src_vq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
+	src_vq->lock = &ctx->vb_mutex;
+	src_vq->min_buffers_needed = 1;
+
+	ret = vb2_queue_init(src_vq);
+	if (ret)
+		return ret;
+
+	dst_vq->type = V4L2_BUF_TYPE_AUDIO_CAPTURE;
+	dst_vq->io_modes = VB2_MMAP | VB2_DMABUF;
+	dst_vq->drv_priv = ctx;
+	dst_vq->buf_struct_size = sizeof(struct v4l2_m2m_buffer);
+	dst_vq->ops = &audm2m_qops;
+	dst_vq->mem_ops = &vb2_vmalloc_memops;
+	dst_vq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
+	dst_vq->lock = &ctx->vb_mutex;
+	dst_vq->min_buffers_needed = 1;
+
+	return vb2_queue_init(dst_vq);
+}
+
+/*
+ * File operations
+ */
+static int audm2m_open(struct file *file)
+{
+	struct audm2m_dev *dev = video_drvdata(file);
+	struct audm2m_ctx *ctx = NULL;
+	int width;
+	int rc = 0;
+
+	if (mutex_lock_interruptible(&dev->dev_mutex))
+		return -ERESTARTSYS;
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx) {
+		rc = -ENOMEM;
+		goto open_unlock;
+	}
+
+	v4l2_fh_init(&ctx->fh, video_devdata(file));
+	file->private_data = &ctx->fh;
+	ctx->dev = dev;
+
+	ctx->q_data[V4L2_M2M_SRC].fmt = &formats[0];
+	ctx->q_data[V4L2_M2M_SRC].rate = 8000;
+	ctx->q_data[V4L2_M2M_SRC].channels = 2;
+
+	/* Fix to 4096 samples */
+	width = snd_pcm_format_physical_width(formats[0].format);
+	ctx->q_data[V4L2_M2M_SRC].buffersize = SAMPLE_NUM * 2 * width;
+	ctx->q_data[V4L2_M2M_DST] = ctx->q_data[V4L2_M2M_SRC];
+
+	ctx->fh.m2m_ctx = v4l2_m2m_ctx_init(dev->m2m_dev, ctx, &queue_init);
+
+	mutex_init(&ctx->vb_mutex);
+
+	if (IS_ERR(ctx->fh.m2m_ctx)) {
+		rc = PTR_ERR(ctx->fh.m2m_ctx);
+
+		v4l2_fh_exit(&ctx->fh);
+		kfree(ctx);
+		goto open_unlock;
+	}
+
+	v4l2_fh_add(&ctx->fh);
+
+	dprintk(dev, 1, "Created instance: %p, m2m_ctx: %p\n",
+		ctx, ctx->fh.m2m_ctx);
+
+open_unlock:
+	mutex_unlock(&dev->dev_mutex);
+	return rc;
+}
+
+static int audm2m_release(struct file *file)
+{
+	struct audm2m_dev *dev = video_drvdata(file);
+	struct audm2m_ctx *ctx = file2ctx(file);
+
+	dprintk(dev, 1, "Releasing instance %p\n", ctx);
+
+	v4l2_fh_del(&ctx->fh);
+	v4l2_fh_exit(&ctx->fh);
+	mutex_lock(&dev->dev_mutex);
+	v4l2_m2m_ctx_release(ctx->fh.m2m_ctx);
+	mutex_unlock(&dev->dev_mutex);
+	kfree(ctx);
+
+	return 0;
+}
+
+static void audm2m_device_release(struct video_device *vdev)
+{
+	struct audm2m_dev *dev = container_of(vdev, struct audm2m_dev, vfd);
+
+	v4l2_device_unregister(&dev->v4l2_dev);
+	v4l2_m2m_release(dev->m2m_dev);
+
+	kfree(dev);
+}
+
+static const struct v4l2_file_operations audm2m_fops = {
+	.owner		= THIS_MODULE,
+	.open		= audm2m_open,
+	.release	= audm2m_release,
+	.poll		= v4l2_m2m_fop_poll,
+	.unlocked_ioctl	= video_ioctl2,
+	.mmap		= v4l2_m2m_fop_mmap,
+};
+
+static const struct video_device audm2m_videodev = {
+	.name		= MEM2MEM_NAME,
+	.vfl_dir	= VFL_DIR_M2M,
+	.fops		= &audm2m_fops,
+	.ioctl_ops	= &audm2m_ioctl_ops,
+	.minor		= -1,
+	.release	= audm2m_device_release,
+	.device_caps	= V4L2_CAP_AUDIO_M2M | V4L2_CAP_STREAMING,
+};
+
+static const struct v4l2_m2m_ops m2m_ops = {
+	.device_run	= device_run,
+};
+
+static int audm2m_probe(struct platform_device *pdev)
+{
+	struct audm2m_dev *dev;
+	struct video_device *vfd;
+	int ret;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	ret = v4l2_device_register(&pdev->dev, &dev->v4l2_dev);
+	if (ret)
+		goto error_free;
+
+	mutex_init(&dev->dev_mutex);
+
+	dev->vfd = audm2m_videodev;
+	vfd = &dev->vfd;
+	vfd->lock = &dev->dev_mutex;
+	vfd->v4l2_dev = &dev->v4l2_dev;
+
+	video_set_drvdata(vfd, dev);
+	v4l2_info(&dev->v4l2_dev,
+		  "Device registered as /dev/v4l-audio%d\n", vfd->num);
+
+	platform_set_drvdata(pdev, dev);
+
+	dev->m2m_dev = v4l2_m2m_init(&m2m_ops);
+	if (IS_ERR(dev->m2m_dev)) {
+		v4l2_err(&dev->v4l2_dev, "Failed to init mem2mem device\n");
+		ret = PTR_ERR(dev->m2m_dev);
+		dev->m2m_dev = NULL;
+		goto error_dev;
+	}
+
+	ret = video_register_device(vfd, VFL_TYPE_AUDIO, 0);
+	if (ret) {
+		v4l2_err(&dev->v4l2_dev, "Failed to register video device\n");
+		goto error_m2m;
+	}
+
+	return 0;
+
+error_m2m:
+	v4l2_m2m_release(dev->m2m_dev);
+error_dev:
+	v4l2_device_unregister(&dev->v4l2_dev);
+error_free:
+	kfree(dev);
+
+	return ret;
+}
+
+static void audm2m_remove(struct platform_device *pdev)
+{
+	struct audm2m_dev *dev = platform_get_drvdata(pdev);
+
+	v4l2_info(&dev->v4l2_dev, "Removing " MEM2MEM_NAME);
+
+	video_unregister_device(&dev->vfd);
+}
+
+static struct platform_driver audm2m_pdrv = {
+	.probe		= audm2m_probe,
+	.remove_new	= audm2m_remove,
+	.driver		= {
+		.name	= MEM2MEM_NAME,
+	},
+};
+
+static void __exit audm2m_exit(void)
+{
+	platform_driver_unregister(&audm2m_pdrv);
+	platform_device_unregister(&audm2m_pdev);
+}
+
+static int __init audm2m_init(void)
+{
+	int ret;
+
+	ret = platform_device_register(&audm2m_pdev);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&audm2m_pdrv);
+	if (ret)
+		platform_device_unregister(&audm2m_pdev);
+
+	return ret;
+}
+
+module_init(audm2m_init);
+module_exit(audm2m_exit);