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 <shengjiu.w...@nxp.com>
> ---
>  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

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