On Wed, Jan 17, 2024 at 6:32 PM Hans Verkuil [off-list ref] wrote:

On 22/11/2023 08:23, Shengjiu Wang wrote:

quoted

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 <redacted>
---
 drivers/media/test-drivers/Kconfig       |  11 +
 drivers/media/test-drivers/Makefile      |   1 +
 drivers/media/test-drivers/vim2m-audio.c | 799 +++++++++++++++++++++++
 3 files changed, 811 insertions(+)
 create mode 100644 drivers/media/test-drivers/vim2m-audio.c

diff --git a/drivers/media/test-drivers/Kconfig b/drivers/media/test-drivers/Kconfig
index 459b433e9fae..55f8af6ee4e2 100644
--- a/drivers/media/test-drivers/Kconfig
+++ b/drivers/media/test-drivers/Kconfig

@@ -17,6 +17,17 @@ config VIDEO_VIM2M
        This is a virtual test device for the memory-to-memory driver
        framework.

+config VIDEO_VIM2M_AUDIO
+     tristate "Virtual Memory-to-Memory Driver For Audio"
+     depends on VIDEO_DEV
+     select VIDEOBUF2_VMALLOC
+     select V4L2_MEM2MEM_DEV
+     select MEDIA_CONTROLLER
+     select MEDIA_CONTROLLER_REQUEST_API

Drop this. This option has been removed.

quoted

+     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..0c61c9ada3e1 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-$(CONFIG_VIDEO_VIM2M_AUDIO) += vim2m-audio.o
 obj-$(CONFIG_VIDEO_VIMC) += vimc/
 obj-$(CONFIG_VIDEO_VIVID) += vivid/
 obj-$(CONFIG_VIDEO_VISL) += visl/

diff --git a/drivers/media/test-drivers/vim2m-audio.c b/drivers/media/test-drivers/vim2m-audio.c
new file mode 100644
index 000000000000..72806ada8628
--- /dev/null
+++ b/drivers/media/test-drivers/vim2m-audio.c

@@ -0,0 +1,799 @@
+// 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");
+
+static unsigned int debug;
+module_param(debug, uint, 0644);
+MODULE_PARM_DESC(debug, "debug level");
+
+#define MEM2MEM_NAME "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,
+};
+
+static u32 formats[] = {
+     V4L2_AUDIO_FMT_S16_LE,
+};
+
+#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;
+     unsigned int            sequence;
+     u32                     fourcc;
+};
+
+enum {
+     V4L2_M2M_SRC = 0,
+     V4L2_M2M_DST = 1,
+};
+
+static snd_pcm_format_t find_format(u32 fourcc)
+{
+     snd_pcm_format_t fmt;
+     unsigned int k;
+
+     for (k = 0; k < NUM_FORMATS; k++) {
+             if (formats[k] == fourcc)
+                     break;
+     }
+
+     if (k == NUM_FORMATS)
+             return 0;
+
+     fmt = v4l2_fourcc_to_audfmt(formats[k]);
+
+     return fmt;
+}
+
+struct audm2m_dev {
+     struct v4l2_device      v4l2_dev;
+     struct video_device     vfd;
+
+     struct mutex            dev_mutex;
+
+     struct v4l2_m2m_dev     *m2m_dev;
+#ifdef CONFIG_MEDIA_CONTROLLER
+     struct media_device     mdev;
+#endif
+};
+
+struct audm2m_ctx {
+     struct v4l2_fh          fh;
+     struct v4l2_ctrl_handler        ctrl_handler;
+     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 = 0;
+     short *src_addr, *dst_addr;
+     int i;
+
+     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);
+     src_buf->sequence = q_data_src->sequence++;
+     dst_buf->sequence = q_data_dst->sequence++;
+     v4l2_m2m_buf_copy_metadata(src_buf, dst_buf, false);
+
+     /* Process the conversion */
+     src_size = vb2_get_plane_payload(&src_buf->vb2_buf, 0);
+
+     src_addr = vb2_plane_vaddr(&src_buf->vb2_buf, 0);
+     dst_addr = vb2_plane_vaddr(&dst_buf->vb2_buf, 0);
+
+     if (q_data_src->rate == q_data_dst->rate) {
+             memcpy(dst_addr, src_addr, src_size);
+             dst_size = src_size;
+     } else if (q_data_src->rate == 2 * q_data_dst->rate) {
+             /* 8k to 16k */
+             for (i = 0; i < src_size / 2; i++) {
+                     *dst_addr++ = *src_addr++;
+                     src_addr++;
+             }
+
+             dst_size = src_size / 2;
+     } else if (q_data_src->rate * 2 == q_data_dst->rate) {
+             /* 16k to 8k */
+             for (i = 0; i < src_size / 2; i++) {
+                     *dst_addr++ = *src_addr;
+                     *dst_addr++ = *src_addr++;
+             }
+
+             dst_size = src_size * 2;
+     }
+
+     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);

You can drop this bus_info line, it's filled in for you.

I see there is a warning from v4l2-compliance test if this line is removed.

warn: v4l2-compliance.cpp(676): media bus_info 'platform:vim2m-audio'
differs from V4L2 bus_info 'platform:vim2m-audio.0'


Best regards
Shengjiu Wang

quoted

+
+     return 0;
+}
+
+static int enum_fmt(struct v4l2_fmtdesc *f)
+{
+     int i, num;
+
+     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 */
+             f->pixelformat = formats[i];
+             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->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, snd_pcm_format_t fmt)
+{
+     f->fmt.audio.channels = 1;
+     f->fmt.audio.buffersize = f->fmt.audio.channels *
+                               snd_pcm_format_physical_width(fmt) *
+                               SAMPLE_NUM;
+     return 0;
+}
+
+static int audm2m_try_fmt_audio_cap(struct file *file, void *priv,
+                                 struct v4l2_format *f)
+{
+     snd_pcm_format_t fmt;
+
+     fmt = find_format(f->fmt.audio.audioformat);
+     if (!fmt) {
+             f->fmt.audio.audioformat = formats[0];
+             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)
+{
+     snd_pcm_format_t fmt;
+
+     fmt = find_format(f->fmt.audio.audioformat);
+     if (!fmt) {
+             f->fmt.audio.audioformat = formats[0];
+             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;
+     snd_pcm_format_t fmt;
+
+     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->fourcc  = f->fmt.audio.audioformat;
+     q_data->channels = f->fmt.audio.channels;
+
+     fmt = find_format(f->fmt.audio.audioformat);
+     q_data->buffersize = q_data->channels *
+                          snd_pcm_format_physical_width(fmt) *
+                          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->fourcc & 0xff),
+             (q_data->fourcc >>  8) & 0xff,
+             (q_data->fourcc >> 16) & 0xff,
+             (q_data->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 int audm2m_start_streaming(struct vb2_queue *q, unsigned int count)
+{
+     struct audm2m_ctx *ctx = vb2_get_drv_priv(q);
+     struct audm2m_q_data *q_data = get_q_data(ctx, q->type);
+
+     q_data->sequence = 0;
+     return 0;
+}
+
+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,
+     .start_streaming = audm2m_start_streaming,
+     .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;

Drop this, it's not needed.

quoted

+
+     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;

Ditto.

quoted

+
+     return vb2_queue_init(dst_vq);
+}
+
+static const s64 audm2m_rates[] = {
+     8000, 16000,
+};
+
+static int audm2m_op_s_ctrl(struct v4l2_ctrl *ctrl)
+{
+     struct audm2m_ctx *ctx =
+             container_of(ctrl->handler, struct audm2m_ctx, ctrl_handler);
+     int ret = 0;
+
+     switch (ctrl->id) {
+     case V4L2_CID_M2M_AUDIO_SOURCE_RATE:
+             ctx->q_data[V4L2_M2M_SRC].rate = ctrl->qmenu_int[ctrl->val];
+             break;
+     case V4L2_CID_M2M_AUDIO_DEST_RATE:
+             ctx->q_data[V4L2_M2M_DST].rate = ctrl->qmenu_int[ctrl->val];
+             break;
+     default:
+             ret = -EINVAL;
+             break;
+     }
+
+     return ret;
+}
+
+static const struct v4l2_ctrl_ops audm2m_ctrl_ops = {
+     .s_ctrl = audm2m_op_s_ctrl,
+};
+
+/*
+ * File operations
+ */
+static int audm2m_open(struct file *file)
+{
+     struct audm2m_dev *dev = video_drvdata(file);
+     struct audm2m_ctx *ctx = NULL;
+     snd_pcm_format_t fmt;
+     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].fourcc = formats[0];
+     ctx->q_data[V4L2_M2M_SRC].rate = 8000;
+     ctx->q_data[V4L2_M2M_SRC].channels = 1;
+
+     /* Fix to 4096 samples */
+     fmt = find_format(formats[0]);
+     width = snd_pcm_format_physical_width(fmt);
+     ctx->q_data[V4L2_M2M_SRC].buffersize = SAMPLE_NUM * 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);
+
+     v4l2_ctrl_handler_init(&ctx->ctrl_handler, 2);
+
+     v4l2_ctrl_new_int_menu(&ctx->ctrl_handler, &audm2m_ctrl_ops,
+                            V4L2_CID_M2M_AUDIO_SOURCE_RATE,
+                            ARRAY_SIZE(audm2m_rates) - 1, 0, audm2m_rates);
+     v4l2_ctrl_new_int_menu(&ctx->ctrl_handler, &audm2m_ctrl_ops,
+                            V4L2_CID_M2M_AUDIO_DEST_RATE,
+                            ARRAY_SIZE(audm2m_rates) - 1, 0, audm2m_rates);
+
+     if (ctx->ctrl_handler.error) {
+             rc = ctx->ctrl_handler.error;
+             v4l2_ctrl_handler_free(&ctx->ctrl_handler);
+             goto err_ctrl_handler;
+     }
+
+     ctx->fh.ctrl_handler = &ctx->ctrl_handler;
+
+     mutex_unlock(&dev->dev_mutex);
+
+     return 0;
+
+err_ctrl_handler:
+     v4l2_m2m_ctx_release(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_ctrl_handler_free(&ctx->ctrl_handler);
+     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);
+
+#ifdef CONFIG_MEDIA_CONTROLLER
+     media_device_cleanup(&dev->mdev);
+#endif
+     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 const struct media_device_ops audm2m_media_ops = {
+     .req_validate = vb2_request_validate,
+     .req_queue = v4l2_m2m_request_queue,
+};
+
+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);
+     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;
+     }
+
+#ifdef CONFIG_MEDIA_CONTROLLER
+     dev->mdev.dev = &pdev->dev;
+     strscpy(dev->mdev.model, MEM2MEM_NAME, sizeof(dev->mdev.model));
+     snprintf(dev->mdev.bus_info, sizeof(dev->mdev.bus_info),
+              "platform:%s", MEM2MEM_NAME);
+     media_device_init(&dev->mdev);
+     dev->mdev.ops = &audm2m_media_ops;
+     dev->v4l2_dev.mdev = &dev->mdev;
+#endif
+
+     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;
+     }
+
+#ifdef CONFIG_MEDIA_CONTROLLER
+     ret = v4l2_m2m_register_media_controller(dev->m2m_dev, vfd,
+                                              MEDIA_ENT_F_PROC_AUDIO_RESAMPLER);
+     if (ret) {
+             v4l2_err(&dev->v4l2_dev, "Failed to init mem2mem media controller\n");
+             goto error_v4l2;
+     }
+
+     ret = media_device_register(&dev->mdev);
+     if (ret) {
+             v4l2_err(&dev->v4l2_dev, "Failed to register mem2mem media device\n");
+             goto error_m2m_mc;
+     }
+#endif
+
+     v4l2_info(&dev->v4l2_dev,
+               "Device registered as /dev/v4l-audio%d\n", vfd->num);
+
+     return 0;
+
+#ifdef CONFIG_MEDIA_CONTROLLER
+error_m2m_mc:
+     v4l2_m2m_unregister_media_controller(dev->m2m_dev);
+#endif
+error_v4l2:
+     video_unregister_device(&dev->vfd);
+     /* audm2m_device_release called by video_unregister_device to release various objects */
+     return ret;
+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);
+
+#ifdef CONFIG_MEDIA_CONTROLLER
+     media_device_unregister(&dev->mdev);
+     v4l2_m2m_unregister_media_controller(dev->m2m_dev);
+#endif
+     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