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Message-ID: <099df0d8-10c8-4a78-827b-7e000f02ca3f@xs4all.nl>
Date: Thu, 18 Jan 2024 08:56:05 +0100
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Subject: Re: [PATCH v11 15/15] media: vim2m-audio: add virtual driver for
 audio memory to memory
Content-Language: en-US, nl
To: Shengjiu Wang <shengjiu.wang@gmail.com>
Cc: Shengjiu Wang <shengjiu.wang@nxp.com>, sakari.ailus@iki.fi,
 tfiga@chromium.org, m.szyprowski@samsung.com, mchehab@kernel.org,
 linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
 Xiubo.Lee@gmail.com, festevam@gmail.com, nicoleotsuka@gmail.com,
 lgirdwood@gmail.com, broonie@kernel.org, perex@perex.cz, tiwai@suse.com,
 alsa-devel@alsa-project.org, linuxppc-dev@lists.ozlabs.org
References: <1700637838-6743-1-git-send-email-shengjiu.wang@nxp.com>
 <1700637838-6743-16-git-send-email-shengjiu.wang@nxp.com>
 <6d96cf56-c534-4abf-8819-03cd32fda3d5@xs4all.nl>
 <CAA+D8ANfkQkuV9YgQQ1ggS2G0GhqvmhZrA6Yn-et0E5z6mPSxQ@mail.gmail.com>
From: Hans Verkuil <hverkuil@xs4all.nl>
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On 18/01/2024 07:13, Shengjiu Wang wrote:
> On Wed, Jan 17, 2024 at 6:32 PM Hans Verkuil <hverkuil@xs4all.nl> wrote:
>>
>> On 22/11/2023 08:23, 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.wang@nxp.com>
>>> ---
>>>  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.
>>
>>> +     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'

You should also drop the line filling in the bus_info in the media device:

<snip>


>>> +static int audm2m_probe(struct platform_device *pdev)
>>> +{

<snip>

>>> +#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);

Drop this line.

>>> +     media_device_init(&dev->mdev);

This function will fill it in automatically as well, and with the same
name as querycap.

Regards,

	Hans

>>> +     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