Re: [RFC v3 07/13] [media] exynos5-fimc-is: Add scaler subdev

[Sylwester Nawrocki <sylvester.nawrocki@gmail.com>]

On 08/02/2013 05:02 PM, Arun Kumar K wrote:
> FIMC-IS has two hardware scalers named as scaler-codec and
> scaler-preview. This patch adds the common code handling the
> video nodes and subdevs of both the scalers.
>
> Signed-off-by: Arun Kumar K<arun.kk@samsung.com>
> Signed-off-by: Kilyeon Im<kilyeon.im@samsung.com>
> ---
>   drivers/media/platform/exynos5-is/fimc-is-scaler.c |  458 ++++++++++++++++++++
>   drivers/media/platform/exynos5-is/fimc-is-scaler.h |  112 +++++
>   2 files changed, 570 insertions(+)
>   create mode 100644 drivers/media/platform/exynos5-is/fimc-is-scaler.c
>   create mode 100644 drivers/media/platform/exynos5-is/fimc-is-scaler.h
>
> diff --git a/drivers/media/platform/exynos5-is/fimc-is-scaler.c b/drivers/media/platform/exynos5-is/fimc-is-scaler.c
> new file mode 100644
> index 0000000..7cff186
> --- /dev/null
> +++ b/drivers/media/platform/exynos5-is/fimc-is-scaler.c
> @@ -0,0 +1,458 @@
> +/*
> + * Samsung EXYNOS5250 FIMC-IS (Imaging Subsystem) driver
> + *
> + * Copyright (C) 2013 Samsung Electronics Co., Ltd.
> + *  Arun Kumar K<arun.kk@samsung.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include<media/v4l2-ioctl.h>
> +#include<media/videobuf2-dma-contig.h>
> +
> +#include "fimc-is.h"
> +
> +#define IS_SCALER_DRV_NAME "fimc-is-scaler"
> +
> +static const struct fimc_is_fmt formats[] = {
> +	{
> +		.name           = "YUV 4:2:0 3p MultiPlanar",
> +		.fourcc         = V4L2_PIX_FMT_YUV420M,
> +		.depth		= {8, 2, 2},
> +		.num_planes     = 3,
> +	},
> +	{
> +		.name           = "YUV 4:2:0 2p MultiPlanar",
> +		.fourcc         = V4L2_PIX_FMT_NV12M,
> +		.depth		= {8, 4},
> +		.num_planes     = 2,
> +	},
> +	{
> +		.name           = "YUV 4:2:2 1p MultiPlanar",
> +		.fourcc         = V4L2_PIX_FMT_NV16,
> +		.depth		= {16},
> +		.num_planes     = 1,
> +	},
> +};
> +#define NUM_FORMATS ARRAY_SIZE(formats)
> +
> +static const struct fimc_is_fmt *find_format(struct v4l2_format *f)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i<  NUM_FORMATS; i++) {
> +		if (formats[i].fourcc == f->fmt.pix_mp.pixelformat)
> +			return&formats[i];
> +	}
> +	return NULL;
> +}
> +
> +static int scaler_video_capture_start_streaming(struct vb2_queue *vq,
> +					unsigned int count)
> +{
> +	struct fimc_is_scaler *ctx = vb2_get_drv_priv(vq);
> +	int ret;
> +
> +	/* Scaler start */
> +	ret = fimc_is_pipeline_scaler_start(ctx->pipeline,
> +			ctx->scaler_id,
> +			(unsigned int **)ctx->buf_paddr,
> +			vq->num_buffers,
> +			ctx->fmt->num_planes);
> +	if (ret) {
> +		pr_err("Scaler start failed.\n");

Please avoid pr_*() and use v4l2_err() or dev_err() where possible.

> +		return -EINVAL;
> +	}
> +
> +	set_bit(STATE_RUNNING,&ctx->capture_state);
> +	return 0;
> +}
> +
> +static int scaler_video_capture_stop_streaming(struct vb2_queue *vq)
> +{
> +	struct fimc_is_scaler *ctx = vb2_get_drv_priv(vq);
> +	int ret;
> +
> +	/* Scaler stop */

Isn't the function name below obvious enough to not require this comment ?

> +	ret = fimc_is_pipeline_scaler_stop(ctx->pipeline, ctx->scaler_id);
> +	if (ret)
> +		pr_debug("Scaler already stopped.\n");
> +
> +	clear_bit(STATE_RUNNING,&ctx->capture_state);
> +	return 0;
> +}
> +
> +static int scaler_video_capture_queue_setup(struct vb2_queue *vq,
> +			const struct v4l2_format *pfmt,
> +			unsigned int *num_buffers, unsigned int *num_planes,
> +			unsigned int sizes[], void *allocators[])
> +{
> +	struct fimc_is_scaler *ctx = vb2_get_drv_priv(vq);
> +	const struct fimc_is_fmt *fmt = ctx->fmt;
> +	unsigned int wh;
> +	int i;
> +
> +	if (!fmt)
> +		return -EINVAL;
> +
> +	*num_planes = fmt->num_planes;
> +	wh = ctx->width * ctx->height;
> +
> +	for (i = 0; i<  *num_planes; i++) {
> +		allocators[i] = ctx->alloc_ctx;
> +		sizes[i] = (wh * fmt->depth[i]) / 8;
> +	}
> +	return 0;
> +}
> +
> +static int scaler_video_capture_buffer_init(struct vb2_buffer *vb)
> +{
> +	struct vb2_queue *vq = vb->vb2_queue;
> +	struct fimc_is_scaler *ctx = vb2_get_drv_priv(vq);
> +	struct fimc_is_buf *buf;
> +	const struct fimc_is_fmt *fmt;
> +	int i;
> +
> +	buf =&ctx->capture_bufs[vb->v4l2_buf.index];

I don't like such usage of vb->v4l2_buf.index. It would be nice to get
rid of this pattern and leave v4l2_buf.index out for videobuf2 and
user space. Or can't it really be avoided ?

> +	/* Initialize buffer */
> +	buf->vb = vb;
> +	fmt = ctx->fmt;
> +	for (i = 0; i<  fmt->num_planes; i++)
> +		buf->paddr[i] = vb2_dma_contig_plane_dma_addr(vb, i);
> +
> +	ctx->cap_buf_cnt++;
> +	return 0;
> +}
> +
> +static void scaler_video_capture_buffer_queue(struct vb2_buffer *vb)
> +{
> +	struct vb2_queue *vq = vb->vb2_queue;
> +	struct fimc_is_scaler *ctx = vb2_get_drv_priv(vq);
> +	struct fimc_is_buf *buf;
> +
> +	buf =&ctx->capture_bufs[vb->v4l2_buf.index];
> +
> +	/* Add buffer to the wait queue */
> +	pr_debug("Add buffer %d in Scaler %d\n",
> +			vb->v4l2_buf.index, ctx->scaler_id);
> +	fimc_is_pipeline_buf_lock(ctx->pipeline);
> +	fimc_is_scaler_wait_queue_add(ctx, buf);
> +	fimc_is_pipeline_buf_unlock(ctx->pipeline);
> +}
> +
> +static void scaler_lock(struct vb2_queue *vq)
> +{
> +	struct fimc_is_scaler *ctx = vb2_get_drv_priv(vq);
> +	mutex_lock(&ctx->video_lock);
> +}
> +
> +static void scaler_unlock(struct vb2_queue *vq)
> +{
> +	struct fimc_is_scaler *ctx = vb2_get_drv_priv(vq);
> +	mutex_unlock(&ctx->video_lock);
> +}
> +
> +static const struct vb2_ops scaler_video_capture_qops = {
> +	.queue_setup		= scaler_video_capture_queue_setup,
> +	.buf_init		= scaler_video_capture_buffer_init,
> +	.buf_queue		= scaler_video_capture_buffer_queue,
> +	.wait_prepare		= scaler_unlock,
> +	.wait_finish		= scaler_lock,

Can't you use vb2_ops_wait_prepare/vb2_ops_wait_finish as in case of
the isp subdev ?

> +	.start_streaming	= scaler_video_capture_start_streaming,
> +	.stop_streaming		= scaler_video_capture_stop_streaming,
> +};
> +
> +static const struct v4l2_file_operations scaler_video_capture_fops = {
> +	.owner		= THIS_MODULE,
> +	.open		= v4l2_fh_open,
> +	.release	= vb2_fop_release,
> +	.poll		= vb2_fop_poll,
> +	.unlocked_ioctl	= video_ioctl2,
> +	.mmap		= vb2_fop_mmap,
> +};
> +
> +/*
> + * Video node ioctl operations
> + */
> +static int scaler_querycap_capture(struct file *file, void *priv,
> +					struct v4l2_capability *cap)
> +{
> +	strncpy(cap->driver, IS_SCALER_DRV_NAME, sizeof(cap->driver) - 1);
> +	strncpy(cap->card, IS_SCALER_DRV_NAME, sizeof(cap->card) - 1);
> +	snprintf(cap->bus_info, sizeof(cap->bus_info), "platform:%s",
> +			IS_SCALER_DRV_NAME);
> +	cap->device_caps = V4L2_CAP_STREAMING | V4L2_CAP_VIDEO_CAPTURE_MPLANE;
> +	cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS;
> +	return 0;
> +}
> +
> +static int scaler_enum_fmt_mplane(struct file *file, void *priv,
> +				     struct v4l2_fmtdesc *f)
> +{
> +	const struct fimc_is_fmt *fmt;
> +
> +	if (f->index>= NUM_FORMATS)
> +		return -EINVAL;
> +
> +	fmt =&formats[f->index];
> +	strlcpy(f->description, fmt->name, sizeof(f->description));
> +	f->pixelformat = fmt->fourcc;
> +	return 0;
> +}
> +
> +static int scaler_g_fmt_mplane(struct file *file, void *priv,
> +				  struct v4l2_format *f)
> +{
> +	struct fimc_is_scaler *ctx = video_drvdata(file);
> +	struct v4l2_pix_format_mplane *pixm =&f->fmt.pix_mp;
> +	const struct fimc_is_fmt *fmt = ctx->fmt;
> +	int i;
> +
> +	for (i = 0; i<  fmt->num_planes; i++) {
> +		struct v4l2_plane_pix_format *plane_fmt =&pixm->plane_fmt[i];
> +		plane_fmt->bytesperline = (ctx->width * fmt->depth[i]) / 8;
> +		plane_fmt->sizeimage = plane_fmt->bytesperline * ctx->height;
> +		memset(plane_fmt->reserved, 0, sizeof(plane_fmt->reserved));
> +	}
> +
> +	pixm->num_planes = fmt->num_planes;
> +	pixm->pixelformat = fmt->fourcc;
> +	pixm->width = ctx->width;
> +	pixm->height = ctx->height;
> +	pixm->field = V4L2_FIELD_NONE;
> +	pixm->colorspace = V4L2_COLORSPACE_JPEG;
> +	memset(pixm->reserved, 0, sizeof(pixm->reserved));
> +
> +	return 0;
> +}
> +
> +static int scaler_try_fmt_mplane(struct file *file, void *priv,
> +				  struct v4l2_format *f)
> +{
> +	const struct fimc_is_fmt *fmt;
> +	struct v4l2_pix_format_mplane *pixm =&f->fmt.pix_mp;
> +	u32 i;
> +
> +	fmt = find_format(f);
> +	if (!fmt)
> +		fmt =&formats[0];
> +
> +	v4l_bound_align_image(&pixm->width, SCALER_MIN_WIDTH,
> +			SCALER_MAX_WIDTH, 0,
> +			&pixm->height, SCALER_MIN_HEIGHT,
> +			SCALER_MAX_HEIGHT, 0, 0);
> +
> +	for (i = 0; i<  fmt->num_planes; i++) {
> +		struct v4l2_plane_pix_format *plane_fmt =&pixm->plane_fmt[i];
> +
> +		plane_fmt->bytesperline = (pixm->width * fmt->depth[i]) / 8;
> +		plane_fmt->sizeimage = (pixm->width * pixm->height *
> +					fmt->depth[i]) / 8;
> +		memset(plane_fmt->reserved, 0, sizeof(plane_fmt->reserved));
> +	}
> +	pixm->num_planes = fmt->num_planes;
> +	pixm->pixelformat = fmt->fourcc;
> +	pixm->colorspace = V4L2_COLORSPACE_JPEG;
> +	pixm->field = V4L2_FIELD_NONE;
> +	memset(pixm->reserved, 0, sizeof(pixm->reserved));
> +
> +	return 0;
> +}
> +
> +static int scaler_s_fmt_mplane(struct file *file, void *priv,
> +				struct v4l2_format *f)
> +{
> +	struct fimc_is_scaler *ctx = video_drvdata(file);

nit: You could add:

	struct v4l2_pix_format_mplane *pixm =&f->fmt.pix_mp;

> +	const struct fimc_is_fmt *fmt;
> +	int ret;
> +
> +	ret = scaler_try_fmt_mplane(file, priv, f);
> +	if (ret)
> +		return ret;
> +
> +	/* Get format type */
> +	fmt = find_format(f);
> +	if (!fmt) {
> +		fmt =&formats[0];
> +		f->fmt.pix_mp.pixelformat = fmt->fourcc;
> +		f->fmt.pix_mp.num_planes = fmt->num_planes;

And then use it here and below.

> +	}
> +
> +	/* Save values to context */
> +	ctx->fmt = fmt;
> +	ctx->width = f->fmt.pix_mp.width;
> +	ctx->height = f->fmt.pix_mp.height;
> +	ctx->pipeline->scaler_width[ctx->scaler_id] = ctx->width;
> +	ctx->pipeline->scaler_height[ctx->scaler_id] = ctx->height;
> +	set_bit(STATE_INIT,&ctx->capture_state);
> +	return 0;
> +}
> +
> +static int scaler_reqbufs(struct file *file, void *priv,
> +		struct v4l2_requestbuffers *reqbufs)
> +{
> +	struct fimc_is_scaler *ctx = video_drvdata(file);
> +	int ret;
> +
> +	reqbufs->count = max_t(u32, FIMC_IS_SCALER_REQ_BUFS_MIN,
> +			reqbufs->count);
> +	ret = vb2_reqbufs(&ctx->vbq, reqbufs);
> +	if (ret) {
> +		pr_err("vb2 req buffers failed\n");
> +		return ret;
> +	}
> +
> +	ctx->cap_buf_cnt = 0;
> +	set_bit(STATE_BUFS_ALLOCATED,&ctx->capture_state);
> +	return 0;
> +}
> +
> +static const struct v4l2_ioctl_ops scaler_video_capture_ioctl_ops = {
> +	.vidioc_querycap		= scaler_querycap_capture,
> +	.vidioc_enum_fmt_vid_cap_mplane	= scaler_enum_fmt_mplane,
> +	.vidioc_try_fmt_vid_cap_mplane	= scaler_try_fmt_mplane,
> +	.vidioc_s_fmt_vid_cap_mplane	= scaler_s_fmt_mplane,
> +	.vidioc_g_fmt_vid_cap_mplane	= scaler_g_fmt_mplane,
> +	.vidioc_reqbufs			= scaler_reqbufs,
> +	.vidioc_querybuf		= vb2_ioctl_querybuf,
> +	.vidioc_qbuf			= vb2_ioctl_qbuf,
> +	.vidioc_dqbuf			= vb2_ioctl_dqbuf,
> +	.vidioc_expbuf			= vb2_ioctl_expbuf,
> +	.vidioc_streamon		= vb2_ioctl_streamon,
> +	.vidioc_streamoff		= vb2_ioctl_streamoff,
> +};
> +
> +static int scaler_subdev_registered(struct v4l2_subdev *sd)
> +{
> +	struct fimc_is_scaler *ctx = v4l2_get_subdevdata(sd);
> +	struct vb2_queue *q =&ctx->vbq;
> +	struct video_device *vfd =&ctx->vfd;
> +	int ret;
> +
> +	mutex_init(&ctx->video_lock);
> +
> +	memset(vfd, 0, sizeof(*vfd));
> +	if (ctx->scaler_id == SCALER_SCC)
> +		snprintf(vfd->name, sizeof(vfd->name), "fimc-is-scaler.codec");
> +	else
> +		snprintf(vfd->name, sizeof(vfd->name),
> +				"fimc-is-scaler.preview");
> +
> +	vfd->fops =&scaler_video_capture_fops;
> +	vfd->ioctl_ops =&scaler_video_capture_ioctl_ops;
> +	vfd->v4l2_dev = sd->v4l2_dev;
> +	vfd->release = video_device_release_empty;
> +	vfd->lock =&ctx->video_lock;
> +	vfd->queue = q;
> +	vfd->vfl_dir = VFL_DIR_RX;
> +	set_bit(V4L2_FL_USE_FH_PRIO,&vfd->flags);
> +
> +	memset(q, 0, sizeof(*q));
> +	q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
> +	q->io_modes = VB2_MMAP | VB2_DMABUF;
> +	q->timestamp_type = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
> +	q->ops =&scaler_video_capture_qops;
> +	q->mem_ops =&vb2_dma_contig_memops;
> +	q->drv_priv = ctx;
> +
> +	ret = vb2_queue_init(q);
> +	if (ret<  0)
> +		return ret;
> +
> +	ctx->vd_pad.flags = MEDIA_PAD_FL_SINK;
> +	ret = media_entity_init(&vfd->entity, 1,&ctx->vd_pad, 0);
> +	if (ret<  0)
> +		return ret;
> +
> +	video_set_drvdata(vfd, ctx);
> +
> +	ret = video_register_device(vfd, VFL_TYPE_GRABBER, -1);
> +	if (ret<  0) {
> +		media_entity_cleanup(&vfd->entity);
> +		return ret;
> +	}
> +
> +	v4l2_info(sd->v4l2_dev, "Registered %s as /dev/%s\n",
> +		  vfd->name, video_device_node_name(vfd));
> +	return 0;
> +}
> +
> +static void scaler_subdev_unregistered(struct v4l2_subdev *sd)
> +{
> +	struct fimc_is_scaler *ctx = v4l2_get_subdevdata(sd);
> +
> +	if (ctx&&  video_is_registered(&ctx->vfd))
> +		video_unregister_device(&ctx->vfd);
> +}
> +
> +static const struct v4l2_subdev_internal_ops scaler_subdev_internal_ops = {
> +	.registered = scaler_subdev_registered,
> +	.unregistered = scaler_subdev_unregistered,
> +};
> +
> +static struct v4l2_subdev_ops scaler_subdev_ops;
> +
> +int fimc_is_scaler_subdev_create(struct fimc_is_scaler *ctx,
> +		enum fimc_is_scaler_id scaler_id,
> +		struct vb2_alloc_ctx *alloc_ctx,
> +		struct fimc_is_pipeline *pipeline)
> +{
> +	struct v4l2_ctrl_handler *handler =&ctx->ctrl_handler;
> +	struct v4l2_subdev *sd =&ctx->subdev;
> +	int ret;
> +
> +	/* Set context data */
> +	ctx->scaler_id = scaler_id;
> +	ctx->alloc_ctx = alloc_ctx;
> +	ctx->pipeline = pipeline;
> +	ctx->fmt =&formats[0];
> +	ctx->width = SCALER_DEF_WIDTH;
> +	ctx->height = SCALER_DEF_HEIGHT;
> +	init_waitqueue_head(&ctx->event_q);
> +	INIT_LIST_HEAD(&ctx->wait_queue);
> +	INIT_LIST_HEAD(&ctx->run_queue);
> +
> +	/* Initialize scaler subdev */
> +	v4l2_subdev_init(sd,&scaler_subdev_ops);
> +	sd->owner = THIS_MODULE;
> +	sd->flags = V4L2_SUBDEV_FL_HAS_DEVNODE;

This should be:

	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;

Please check if the flags are not being overwritten for the other subdevs.

> +	if (scaler_id == SCALER_SCC)
> +		snprintf(sd->name, sizeof(sd->name), "fimc-is-scc");
> +	else
> +		snprintf(sd->name, sizeof(sd->name), "fimc-is-scp");
> +
> +	ctx->subdev_pads[SCALER_SD_PAD_SINK].flags = MEDIA_PAD_FL_SINK;
> +	ctx->subdev_pads[SCALER_SD_PAD_SRC_FIFO].flags = MEDIA_PAD_FL_SOURCE;
> +	ctx->subdev_pads[SCALER_SD_PAD_SRC_DMA].flags = MEDIA_PAD_FL_SOURCE;
> +	ret = media_entity_init(&sd->entity, ISP_SD_PADS_NUM,
> +			ctx->subdev_pads, 0);
> +	if (ret<  0)
> +		return ret;
> +
> +	ret = v4l2_ctrl_handler_init(handler, 1);
> +	if (handler->error)
> +		goto err_ctrl;
> +
> +	sd->ctrl_handler = handler;
> +	sd->internal_ops =&scaler_subdev_internal_ops;
> +	v4l2_set_subdevdata(sd, ctx);
> +
> +	return 0;
> +err_ctrl:
> +	media_entity_cleanup(&sd->entity);
> +	v4l2_ctrl_handler_free(handler);
> +	return ret;
> +}
> +
> +void fimc_is_scaler_subdev_destroy(struct fimc_is_scaler *ctx)
> +{
> +	struct v4l2_subdev *sd =&ctx->subdev;
> +
> +	v4l2_device_unregister_subdev(sd);
> +	media_entity_cleanup(&sd->entity);
> +	v4l2_ctrl_handler_free(&ctx->ctrl_handler);
> +	v4l2_set_subdevdata(sd, NULL);
> +}
> +
> diff --git a/drivers/media/platform/exynos5-is/fimc-is-scaler.h b/drivers/media/platform/exynos5-is/fimc-is-scaler.h
> new file mode 100644
> index 0000000..6d3d831
> --- /dev/null
> +++ b/drivers/media/platform/exynos5-is/fimc-is-scaler.h
> @@ -0,0 +1,112 @@
> +/*
> + * Samsung EXYNOS4x12 FIMC-IS (Imaging Subsystem) driver
> + *
> + * Copyright (C) 2013 Samsung Electronics Co., Ltd.
> + *  Arun Kumar K<arun.kk@samsung.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +#ifndef FIMC_IS_SCALER_H_
> +#define FIMC_IS_SCALER_H_
> +
> +#include<linux/sizes.h>
> +#include<linux/io.h>
> +#include<linux/irqreturn.h>
> +#include<linux/platform_device.h>
> +#include<linux/sched.h>
> +#include<linux/spinlock.h>
> +#include<linux/types.h>
> +#include<linux/videodev2.h>
> +
> +#include<media/media-entity.h>
> +#include<media/videobuf2-core.h>
> +#include<media/v4l2-device.h>
> +#include<media/v4l2-mediabus.h>
> +#include<media/s5p_fimc.h>
> +
> +#include "fimc-is-core.h"
> +
> +#define SCALER_SD_PAD_SINK	0
> +#define SCALER_SD_PAD_SRC_FIFO	1
> +#define SCALER_SD_PAD_SRC_DMA	2
> +#define SCALER_SD_PADS_NUM	3
> +
> +#define SCALER_MAX_BUFS		32
> +#define SCALER_MAX_PLANES	3
> +
> +#define FIMC_IS_SCALER_REQ_BUFS_MIN	2
> +
> +#define SCALER_DEF_WIDTH	1280
> +#define SCALER_DEF_HEIGHT	720
> +#define SCALER_MAX_WIDTH	4808
> +#define SCALER_MAX_HEIGHT	3356
> +#define SCALER_MIN_WIDTH	32
> +#define SCALER_MIN_HEIGHT	32
> +
> +/**
> + * struct fimc_is_scaler - fimc-is scaler structure
> + * @vfd: video device node
> + * @fh: v4l2 file handle
> + * @alloc_ctx: videobuf2 memory allocator context
> + * @subdev: fimc-is-scaler subdev
> + * @vd_pad: media pad for the output video node
> + * @subdev_pads: the subdev media pads
> + * @ctrl_handler: v4l2 control handler
> + * @video_lock: video lock mutex
> + * @event_q: notifies scaler events
> + * @pipeline: pipeline instance for this scaler context
> + * @scaler_id: distinguishes scaler preview or scaler codec
> + * @vbq: vb2 buffers queue for ISP output video node
> + * @wait_queue: list holding buffers waiting to be queued to HW
> + * @wait_queue_cnt: wait queue number of buffers
> + * @run_queue: list holding buffers queued to HW
> + * @run_queue_cnt: run queue number of buffers
> + * @capture_bufs: scaler capture buffers array
> + * @cap_buf_cnt: number of capture buffers in use
> + * @fmt: capture plane format for scaler
> + * @width: user configured output width
> + * @height: user configured output height
> + * @capture_state: state of the capture video node operations
> + * @buf_paddr: holds the physical address of capture buffers
> + */
> +struct fimc_is_scaler {
> +	struct video_device		vfd;
> +	struct v4l2_fh			fh;
> +	struct vb2_alloc_ctx		*alloc_ctx;
> +	struct v4l2_subdev		subdev;
> +	struct media_pad		vd_pad;
> +	struct media_pad		subdev_pads[SCALER_SD_PADS_NUM];
> +	struct v4l2_mbus_framefmt	subdev_fmt;
> +	struct v4l2_ctrl_handler	ctrl_handler;
> +
> +	struct mutex		video_lock;
> +	wait_queue_head_t	event_q;
> +
> +	struct fimc_is_pipeline	*pipeline;
> +	enum fimc_is_scaler_id	scaler_id;
> +
> +	struct vb2_queue	vbq;
> +	struct list_head	wait_queue;
> +	unsigned int		wait_queue_cnt;
> +	struct list_head	run_queue;
> +	unsigned int		run_queue_cnt;
> +
> +	struct fimc_is_buf	capture_bufs[SCALER_MAX_BUFS];
> +	unsigned int		cap_buf_cnt;
> +
> +	const struct fimc_is_fmt *fmt;
> +	unsigned int		width;
> +	unsigned int		height;
> +	unsigned long		capture_state;
> +	unsigned int		buf_paddr[SCALER_MAX_BUFS][SCALER_MAX_PLANES];
> +};
> +
> +int fimc_is_scaler_subdev_create(struct fimc_is_scaler *ctx,
> +		enum fimc_is_scaler_id scaler_id,
> +		struct vb2_alloc_ctx *alloc_ctx,
> +		struct fimc_is_pipeline *pipeline);
> +void fimc_is_scaler_subdev_destroy(struct fimc_is_scaler *scaler);
> +
> +#endif /* FIMC_IS_SCALER_H_ */