[v4l-utils,v7,7/7] Add a libv4l plugin for Exynos4 camera

Commit Message

Jacek Anaszewski Oct. 12, 2016, 2:35 p.m. UTC

The plugin provides support for the media device on Exynos4 SoC.
It performs single plane <-> multi plane API conversion,
video pipeline linking and takes care of automatic data format
negotiation for the whole pipeline, after intercepting
VIDIOC_S_FMT or VIDIOC_TRY_FMT ioctls.

Signed-off-by: Jacek Anaszewski <[e-mail]>
Acked-by: Kyungmin Park <[e-mail]>
---
 configure.ac                                      |    1 +
 lib/Makefile.am                                   |    5 +
 lib/libv4l-exynos4-camera/Makefile.am             |   19 +
 lib/libv4l-exynos4-camera/libv4l-exynos4-camera.c | 1325 +++++++++++++++++++++
 4 files changed, 1350 insertions(+)
 create mode 100644 lib/libv4l-exynos4-camera/Makefile.am
 create mode 100644 lib/libv4l-exynos4-camera/libv4l-exynos4-camera.c

Comments

Sakari Ailus Nov. 24, 2016, 3:11 p.m. UTC | #1

Hi Jacek,

Thank you for your continued work on the Exynos plugin patchset!

I think we're pretty close to being able to merge the set, if you could
still bear with me awhile. :-)

On Wed, Oct 12, 2016 at 04:35:22PM +0200, Jacek Anaszewski wrote:
...
> diff --git a/lib/libv4l-exynos4-camera/Makefile.am b/lib/libv4l-exynos4-camera/Makefile.am
> new file mode 100644
> index 0000000..c38b7f6
> --- /dev/null
> +++ b/lib/libv4l-exynos4-camera/Makefile.am
> @@ -0,0 +1,19 @@
> +if WITH_V4L_PLUGINS
> +libv4l2plugin_LTLIBRARIES = libv4l-exynos4-camera.la
> +endif
> +
> +media-bus-format-names.h: ../../include/linux/media-bus-format.h
> +	sed -e '/#define MEDIA_BUS_FMT/ ! d; s/.*FMT_//; /FIXED/ d; s/\t.*//; s/.*/{ \"&\", MEDIA_BUS_FMT_& },/;' \
> +	< $< > $@
> +
> +media-bus-format-codes.h: ../../include/linux/media-bus-format.h
> +	sed -e '/#define MEDIA_BUS_FMT/ ! d; s/.*#define //; /FIXED/ d; s/\t.*//; s/.*/ &,/;' \
> +	< $< > $@
> +
> +BUILT_SOURCES = media-bus-format-names.h media-bus-format-codes.h
> +CLEANFILES = $(BUILT_SOURCES)

It'd be nice to be able to use the same generated headers that now are under
utils/media-ctl, instead of copying the sed script here in verbatim. If the
script is changed or fixed in some way, the other location probably will
remain unchanged...

I wonder if there's a proper way to generate build time headers such as
these.

Another less good alternative would be to put these into a separate Makefile
and include that Makefile where the headers are needed. But I don't like
that much either, it's a hack.

> +
> +nodist_libv4l_exynos4_camera_la_SOURCES = $(BUILT_SOURCES)
> +libv4l_exynos4_camera_la_SOURCES = libv4l-exynos4-camera.c ../../utils/media-ctl/libmediactl.c ../../utils/media-ctl/libv4l2subdev.c ../../utils/media-ctl/mediatext.c
> +libv4l_exynos4_camera_la_CFLAGS = -fvisibility=hidden -std=gnu99
> +libv4l_exynos4_camera_la_LDFLAGS = -avoid-version -module -shared -export-dynamic -lpthread
> diff --git a/lib/libv4l-exynos4-camera/libv4l-exynos4-camera.c b/lib/libv4l-exynos4-camera/libv4l-exynos4-camera.c
> new file mode 100644
> index 0000000..c219fe5
> --- /dev/null
> +++ b/lib/libv4l-exynos4-camera/libv4l-exynos4-camera.c
> @@ -0,0 +1,1325 @@
> +/*
> + * Copyright (c) 2016 Samsung Electronics Co., Ltd.
> + *              http://www.samsung.com
> + *
> + * Author: Jacek Anaszewski <[e-mail]>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU Lesser General Public License as published by
> + * the Free Software Foundation; either version 2.1 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + */
> +
> +#include <config.h>
> +#include <errno.h>
> +#include <linux/types.h>
> +#include <stdbool.h>
> +#include <stdint.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <sys/ioctl.h>
> +#include <sys/syscall.h>
> +#include <unistd.h>
> +
> +#include "../../utils/media-ctl/mediactl.h"
> +#include "../../utils/media-ctl/mediatext.h"
> +#include "../../utils/media-ctl/v4l2subdev.h"
> +#include "libv4l-plugin.h"
> +
> +#ifdef DEBUG
> +#define V4L2_EXYNOS4_DBG(format, ARG...)\
> +	printf("[%s:%d] [%s] " format " \n", __FILE__, __LINE__, __func__, ##ARG)
> +#else
> +#define V4L2_EXYNOS4_DBG(format, ARG...)
> +#endif
> +
> +#define V4L2_EXYNOS4_ERR(format, ARG...)\
> +	fprintf(stderr, "Libv4l Exynos4 camera plugin: "format "\n", ##ARG)
> +
> +#define V4L2_EXYNOS4_LOG(format, ARG...)\
> +	fprintf(stdout, "Libv4l Exynos4 camera plugin: "format "\n", ##ARG)
> +
> +#define VIDIOC_CTRL(type)				\
> +	((type) == VIDIOC_S_CTRL ? "VIDIOC_S_CTRL" :	\
> +				   "VIDIOC_G_CTRL")
> +
> +#if HAVE_VISIBILITY
> +#define PLUGIN_PUBLIC __attribute__ ((visibility("default")))
> +#else
> +#define PLUGIN_PUBLIC
> +#endif
> +
> +#define SYS_IOCTL(fd, cmd, arg) \
> +	syscall(SYS_ioctl, (int)(fd), (unsigned long)(cmd), (void *)(arg))
> +
> +#define SIMPLE_CONVERT_IOCTL(fd, cmd, arg, __struc) ({  \
> +	int __ret;                                      \
> +	struct __struc *req = arg;                      \
> +	uint32_t type = req->type;                      \
> +	req->type = convert_type(type);                 \
> +	__ret = SYS_IOCTL(fd, cmd, arg);                \
> +	req->type = type;                               \
> +	__ret;                                          \
> +	})
> +
> +#ifndef min
> +#define min(a, b) (((a) < (b)) ? (a) : (b))
> +#endif
> +
> +#ifndef max
> +#define max(a, b) (((a) > (b)) ? (a) : (b))
> +#endif
> +
> +#define EXYNOS4_FIMC_DRV	"exynos4-fimc"
> +#define EXYNOS4_FIMC_LITE_DRV	"exynos-fimc-lit"
> +#define EXYNOS4_FIMC_IS_ISP_DRV	"exynos4-fimc-is"
> +#define EXYNOS4_CAPTURE_CONF	"/var/lib/libv4l/exynos4_capture_conf"

Is this something that should be configurable in ./configure?

> +#define EXYNOS4_FIMC_IS_ISP	"FIMC-IS-ISP"
> +#define EXYNOS4_S5K6A3		"S5K6A3"

Maybe this one as well. But it could come from a configuration file, too.

The problem at large is actually something else: how do you recognise the
hardware you're running on?

You could find the sensor by walking the media graph.

But if you need to know something very hardware specific it might not be
available through the generic interfaces, and you might need to know the
exact hardware you have.

How do you know that you should load a particular plugin? I wonder if we
could add a small snippet of code to detect different kinds of systems, I
presume this is the plugin you want to load if the user has opened a video
node of the Exynos4 ISP; you could find through the Media controller.

That's certainly out of scope of the patchset, I just thought of binging up
the topics for discussion. :-)

> +#define EXYNOS4_FIMC_LITE_PREFIX "FIMC-LITE."
> +#define EXYNOS4_FIMC_PREFIX	"FIMC."
> +#define EXYNOS4_MAX_FMT_NEGO_NUM 50
> +#define EXYNOS4_MAX_PIPELINE_LEN 7
> +
> +struct media_device;
> +struct media_entity;
> +
> +/*
> + * struct pipeline_entity - linked media device pipeline
> + * @entity:		linked entity
> + * @sink_pad:		inbound link pad of the entity
> + * @src_pad:		outbound link pad of the entity
> + */
> +struct pipeline_entity {
> +	struct media_entity *entity;
> +	struct media_pad *sink_pad;
> +	struct media_pad *src_pad;
> +};
> +
> +/*
> + * struct media_entity_to_cid - entity to control map
> + * @entity:		media entity
> + * @sink_pad:		inbound link pad of the entity
> + * @src_pad:		outbound link pad of the entity
> + */
> +struct media_entity_to_cid {
> +	struct media_entity *entity;
> +	union {
> +		struct v4l2_queryctrl queryctrl;
> +		struct v4l2_query_ext_ctrl query_ext_ctrl;
> +	};
> +};
> +
> +/*
> + * struct exynos4_camera_plugin - libv4l exynos4 camera plugin
> + * @media:		media device comprising the opened video device
> + * @pipeline:		video pipeline, element 0 is the source entity
> + * @pipeline_len:	length of the video pipeline
> + */
> +struct exynos4_camera_plugin {

static?

> +	struct media_device *media;
> +	struct pipeline_entity pipeline[EXYNOS4_MAX_PIPELINE_LEN];
> +	unsigned int pipeline_len;
> +};
> +
> +/* -----------------------------------------------------------------------------
> + * Pipeline operations
> + */
> +
> +/**
> + * @brief Discover video pipeline for given sink entity
> + * @param plugin - this plugin.
> + * @param entity - sink entity of the pipeline.
> + *
> + * Discover the video pipeline, by walking starting from the
> + * sink entity upwards until a source entity is encountered.
> + *
> + * @return 0 if the sensor entity was detected,
> + * 	   or negative error code on failure.
> + */
> +static int discover_pipeline_by_entity(struct exynos4_camera_plugin *plugin,
> +				       struct media_entity *entity)
> +{
> +	struct pipeline_entity reverse_pipeline[EXYNOS4_MAX_PIPELINE_LEN];
> +	struct media_pad *src_pad;
> +	struct media_link *link = NULL, *backlinks[2];
> +	unsigned int num_backlinks, cur_pipe_pos = 0;
> +	int i, j;
> +	int ret;
> +
> +	if (entity == NULL)
> +		return -EINVAL;
> +
> +	for (;;) {
> +		/* Cache the recently discovered entity. */
> +		reverse_pipeline[cur_pipe_pos].entity = entity;
> +
> +		/* Cache the source pad used for linking the entity. */
> +		if (link)
> +			reverse_pipeline[cur_pipe_pos].src_pad = link->source;
> +
> +		ret = media_entity_get_backlinks(entity, backlinks,
> +						 &num_backlinks);
> +		if (ret < 0)
> +			return ret;
> +
> +		/* Check if pipeline source entity has been reached. */
> +		if (num_backlinks > 2) {
> +			V4L2_EXYNOS4_DBG("Unexpected number of busy sink pads (%d)",
> +					 num_backlinks);
> +			return -EINVAL;
> +		} else if (num_backlinks == 2) {
> +			/*
> +			 * Allow two active pads only in case of
> +			 * S5C73M3-OIF entity.
> +			 */
> +			if (strcmp(media_entity_get_info(entity)->name,
> +				   "S5C73M3-OIF")) {
> +				V4L2_EXYNOS4_DBG("Ambiguous media device topology: "
> +						 "two busy sink pads");
> +				return -EINVAL;
> +			}
> +			/*
> +			 * Two active links are allowed betwen S5C73M3-OIF and
> +			 * S5C73M3 entities. In such a case route through the
> +			 * pad with id == 0 has to be chosen.
> +			 */
> +			link = NULL;
> +			for (i = 0; i < num_backlinks; i++)
> +				if (backlinks[i]->sink->index == 0)
> +					link = backlinks[i];
> +			if (link == NULL)
> +				return -EINVAL;
> +		} else if (num_backlinks == 1) {
> +			link = backlinks[0];
> +		} else {
> +			reverse_pipeline[cur_pipe_pos].sink_pad = NULL;
> +			break;
> +		}
> +
> +		/* Cache the sink pad used for linking the entity. */
> +		reverse_pipeline[cur_pipe_pos].sink_pad = link->sink;
> +
> +		V4L2_EXYNOS4_DBG("Discovered sink pad %d for the %s entity",
> +				 reverse_pipeline[cur_pipe_pos].sink_pad->index,
> +				 media_entity_get_info(entity)->name);
> +
> +		src_pad = media_entity_remote_source(link->sink);
> +		if (!src_pad)
> +			return -EINVAL;
> +
> +		entity = src_pad->entity;
> +		if (++cur_pipe_pos == EXYNOS4_MAX_PIPELINE_LEN)
> +			return -EINVAL;
> +	}
> +
> +	/*
> +	 * Reorder discovered pipeline elements so that the sensor
> +	 * entity was the pipeline head.
> +	 */
> +	j = 0;
> +	for (i = cur_pipe_pos; i >= 0; i--)

How about:

	for (i = cur_pipe_pos, j = 0; i >= 0; i--, j++)

And you can avoid setting j to zero outside the loop plus incrementing j++
where it doesn't seem to fit too well.

> +		plugin->pipeline[j++] = reverse_pipeline[i];
> +
> +	plugin->pipeline_len = j;
> +
> +	return 0;
> +}
> +
> +/**
> + * @brief Check if the entity belongs to the plugin video pipeline
> + * @param plugin - this plugin.
> + * @param entity_name - name of the entity to look for.
> + *
> + * Check if the entity belongs to the pipeline whose sink element
> + * is the video device represented by the file descriptor passed
> + * to plugin_init().
> + *
> + * @return True if the entity belongs to the pipeline,
> + *         and false otherwise.
> + */
> +static bool has_pipeline_entity(struct exynos4_camera_plugin *plugin,
> +				char *entity_name)
> +{
> +	struct pipeline_entity *pipeline = plugin->pipeline;
> +	struct media_entity *entity;
> +	unsigned int i;
> +
> +	if (pipeline == NULL || entity_name == NULL)
> +		return -EINVAL;
> +
> +	for (i = 0; i < plugin->pipeline_len; i++) {
> +		entity = pipeline[i].entity;
> +		if (!strncmp(media_entity_get_info(entity)->name, entity_name,
> +			     strlen(entity_name)))
> +			return true;
> +	}
> +
> +	return false;
> +}
> +
> +/**
> + * @brief Adjust mbus format to FIMC_IS_ISP limitations.
> + * @param mbus_fmt - format to adjust.
> + *
> + * FIMC_IS_ISP shears the video frame off, effectively the format set
> + * on the preceding entities has to be suitably greater to achieve
> + * the frame size requested by the user.
> + *
> + * Also the miminum frame size supported by FIMC_IS_ISP is 128x128.
> + */
> +static void adjust_format_to_fimc_is_isp(struct v4l2_mbus_framefmt *mbus_fmt)
> +{
> +	mbus_fmt->width = max(128, mbus_fmt->width);
> +	mbus_fmt->height = max(128, mbus_fmt->height);
> +
> +	mbus_fmt->width += 16;
> +	mbus_fmt->height += 12;
> +}
> +
> +/**
> + * @brief Negotiate format acceptable for all pipeline entities.
> + * @param plugin - this plugin.
> + * @param dev_fmt - requested video device format.
> + *
> + * Negotiate common format acceptable by all the pipeline entities,
> + * that is closest to the requested one.
> + *
> + * @return 0 if the negotiation succeeded,
> + * 	   or negative error code on failure.
> + */
> +static int negotiate_pipeline_fmt(struct exynos4_camera_plugin *plugin,
> +				  struct v4l2_format *dev_fmt)
> +{
> +	struct v4l2_mbus_framefmt mbus_fmt = { 0 }, common_fmt;
> +	int repeat_negotiation, cnt_negotiation = 0, ret, pad_id, i;
> +	struct pipeline_entity *pipeline = plugin->pipeline;
> +	enum v4l2_subdev_fmt_mismatch fmt_err;
> +	struct media_entity *entity;
> +
> +	if (pipeline == NULL || dev_fmt == NULL)
> +		return -EINVAL;
> +
> +	mbus_fmt.width = dev_fmt->fmt.pix_mp.width;
> +	mbus_fmt.height = dev_fmt->fmt.pix_mp.height;
> +	mbus_fmt.field = dev_fmt->fmt.pix_mp.field;
> +	mbus_fmt.colorspace = dev_fmt->fmt.pix_mp.colorspace;
> +
> +	if (has_pipeline_entity(plugin, EXYNOS4_FIMC_IS_ISP))
> +		adjust_format_to_fimc_is_isp(&mbus_fmt);
> +
> +	V4L2_EXYNOS4_DBG("Begin pipeline format negotiation...");
> +
> +	for (;;) {
> +		repeat_negotiation = 0;
> +		entity = pipeline[0].entity;
> +
> +		pad_id = pipeline[0].src_pad->index;
> +
> +		V4L2_EXYNOS4_DBG("Setting format on the source entity pad %s:%d",
> +				 media_entity_get_info(entity)->name, pad_id);
> +
> +		ret = v4l2_subdev_set_format(entity, &mbus_fmt,
> +					     pad_id, V4L2_SUBDEV_FORMAT_TRY);
> +		if (ret < 0)
> +			return ret;
> +
> +		V4L2_EXYNOS4_DBG("Format set on the pad %s:%d: mcode: %s, cs: %s, w: %d, h: %d",
> +				 media_entity_get_info(entity)->name, pad_id,
> +				 v4l2_subdev_pixelcode_to_string(mbus_fmt.code),
> +				 v4l2_subdev_colorspace_to_string(mbus_fmt.colorspace),
> +				 mbus_fmt.width, mbus_fmt.height);
> +
> +		common_fmt = mbus_fmt;
> +
> +		/* Stop iterating on last but one entity as it is not a sub-device. */
> +		for (i = 1; i < plugin->pipeline_len - 1; i++) {
> +			entity = pipeline[i].entity;
> +
> +			pad_id = pipeline[i].sink_pad->index;
> +
> +			V4L2_EXYNOS4_DBG("Setting format on the pad %s:%d: mcode: %s, cs: %s, w: %d, h: %d",
> +					 media_entity_get_info(entity)->name, pad_id,
> +					 v4l2_subdev_pixelcode_to_string(mbus_fmt.code),
> +					 v4l2_subdev_colorspace_to_string(mbus_fmt.colorspace),
> +					 mbus_fmt.width, mbus_fmt.height);
> +
> +			/* Set format on the entity sink pad. */
> +			ret = v4l2_subdev_set_format(entity, &mbus_fmt, pad_id,
> +							V4L2_SUBDEV_FORMAT_TRY);
> +			if (ret < 0)
> +				return ret;
> +
> +			fmt_err = v4l2_subdev_format_compare(&mbus_fmt, &common_fmt);
> +			if (fmt_err) {
> +				if (fmt_err == FMT_MISMATCH_WIDTH &&
> +				     !strncmp(media_entity_get_info(entity)->name,
> +					      EXYNOS4_FIMC_LITE_PREFIX,
> +					      strlen(EXYNOS4_FIMC_LITE_PREFIX))) {
> +					/*
> +					 * Align width downwards, according to the FIMC-LITE
> +					 * width step. Otherwise pipeline format negotiation
> +					 * wouldn't succeed for widths excessing maximum sensor
> +					 * frame width, which is probed by GStreamer, no matter
> +					 * what actual frame size is to be set.
> +					 */
> +					mbus_fmt.width -= 8;
> +				}
> +				repeat_negotiation = 1;
> +				break;
> +			}
> +
> +			/*
> +			 * Do not check format on FIMC.[n] source pad
> +			 * and stop negotiation.
> +			 */
> +			if (!strncmp(media_entity_get_info(entity)->name,
> +				     EXYNOS4_FIMC_PREFIX,
> +				     strlen(EXYNOS4_FIMC_PREFIX)))
> +				break;
> +
> +			pad_id = pipeline[i].src_pad->index;
> +
> +			/* Get format on the entity src pad */
> +			ret = v4l2_subdev_get_format(entity, &mbus_fmt, pad_id,
> +							V4L2_SUBDEV_FORMAT_TRY);
> +			if (ret < 0)
> +				return -EINVAL;
> +
> +			V4L2_EXYNOS4_DBG("Format propagated to the pad %s:%d: mcode: %s, cs: %s, w: %d, h: %d",
> +					 media_entity_get_info(entity)->name, pad_id,
> +					 v4l2_subdev_pixelcode_to_string(mbus_fmt.code),
> +					 v4l2_subdev_colorspace_to_string(mbus_fmt.colorspace),
> +					 mbus_fmt.width, mbus_fmt.height);
> +
> +			if (!strcmp(media_entity_get_info(entity)->name,
> +				    EXYNOS4_FIMC_IS_ISP)) {
> +				common_fmt.code = mbus_fmt.code;
> +				common_fmt.colorspace = mbus_fmt.colorspace;
> +				common_fmt.width -= 16;
> +				common_fmt.height -= 12;
> +			}
> +
> +			if (v4l2_subdev_format_compare(&mbus_fmt, &common_fmt)) {
> +				repeat_negotiation = 1;
> +				break;
> +			}
> +		}
> +
> +		if (!repeat_negotiation) {
> +			break;
> +		} else if (++cnt_negotiation > EXYNOS4_MAX_FMT_NEGO_NUM) {
> +			V4L2_EXYNOS4_DBG("Pipeline format negotiation failed!");
> +			return -EINVAL;
> +		}
> +	}
> +
> +	dev_fmt->fmt.pix_mp.width = mbus_fmt.width;
> +	dev_fmt->fmt.pix_mp.height = mbus_fmt.height;
> +	dev_fmt->fmt.pix_mp.field = mbus_fmt.field;
> +	dev_fmt->fmt.pix_mp.colorspace = mbus_fmt.colorspace;
> +
> +	V4L2_EXYNOS4_DBG("Pipeline format successfuly negotiated");
> +
> +	return 0;
> +}
> +
> +/**
> + * @brief Apply previously negotiated pipeline format
> + * @param plugin - this plugin.
> + *
> + * Apply the format, previously negotiated with negotiate_pipeline_fmt(),
> + * on all the pipeline v4l2 sub-devices.
> + *
> + * @return 0 if the format was successfuly applied,
> + * 	   or negative error code on failure.
> + */
> +static int apply_pipeline_fmt(struct exynos4_camera_plugin *plugin,
> +			      struct v4l2_format *fmt)
> +{
> +	struct v4l2_mbus_framefmt mbus_fmt = { 0 };
> +	struct pipeline_entity *pipeline = plugin->pipeline;
> +	struct media_entity *entity;
> +	struct media_pad *pad;
> +	unsigned int i;
> +	int ret;
> +
> +	if (pipeline == NULL)
> +		return -EINVAL;
> +
> +	for (i = 0; i < plugin->pipeline_len - 1; i++) {
> +		entity = pipeline[i].entity;
> +		/*
> +		 * Source entity is linked only through a source pad
> +		 * and this pad should be used for setting the format.
> +		 * For other entities set the format on a sink pad.
> +		 */
> +		pad = pipeline[i].sink_pad ? pipeline[i].sink_pad :
> +					pipeline[i].src_pad;
> +		if (pad == NULL)
> +			return -EINVAL;
> +
> +		ret = v4l2_subdev_get_format(entity, &mbus_fmt, pad->index,
> +					     V4L2_SUBDEV_FORMAT_TRY);
> +
> +		if (ret < 0)
> +			return ret;
> +
> +		V4L2_EXYNOS4_DBG("VIDIOC_SUBDEV_G_FMT %s:%d: mcode: %s, cs: %s, w: %d, h: %d",
> +			  media_entity_get_info(entity)->name, pad->index,
> +			  v4l2_subdev_pixelcode_to_string(mbus_fmt.code),
> +			  v4l2_subdev_colorspace_to_string(mbus_fmt.colorspace),
> +			  mbus_fmt.width, mbus_fmt.height);
> +
> +		ret = v4l2_subdev_set_format(entity, &mbus_fmt, pad->index,
> +					     V4L2_SUBDEV_FORMAT_ACTIVE);
> +		if (ret < 0)
> +			return ret;
> +
> +		V4L2_EXYNOS4_DBG("VIDIOC_SUBDEV_S_FMT %s:%d: mcode: %s, cs: %s, w: %d, h: %d",
> +			  media_entity_get_info(entity)->name, pad->index,
> +			  v4l2_subdev_pixelcode_to_string(mbus_fmt.code),
> +			  v4l2_subdev_colorspace_to_string(mbus_fmt.colorspace),
> +			  mbus_fmt.width, mbus_fmt.height);
> +	}
> +
> +	/*
> +	 * Sink entity represents /dev/videoN node and is not
> +	 * a sub-device. Nonetheless because it has associated
> +	 * file descriptor and can expose v4l2-controls the
> +	 * v4l2-subdev structure is used for caching the
> +	 * related data.
> +	 */
> +	struct v4l2_subdev *sd =
> +		media_entity_get_v4l2_subdev(pipeline[i].entity);
> +	if (!sd)
> +		return -EINVAL;
> +
> +	ret = SYS_IOCTL(sd->fd, VIDIOC_S_FMT, fmt);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +/**
> + * @brief Open all v4l2 sub-devices associated with pipeline entities
> + * @param plugin - this plugin.
> + *
> + * Open all v4l2 sub-devices associated with the entities of the pipeline
> + * discovered with discover_pipeline_by_entity().
> + *
> + * @return 0 if all v4l2 sub-devices were opened successfuly,
> + * 	   or negative error code on failure.
> + */
> +static int open_pipeline(struct exynos4_camera_plugin *plugin)
> +{
> +	struct pipeline_entity *pipeline = plugin->pipeline;
> +	struct media_entity *entity;
> +	unsigned int i;
> +	int ret;
> +
> +	if (pipeline == NULL)
> +		return -EINVAL;
> +
> +	/*
> +	 * Stop walking the pipeline on the last but one entity, because
> +	 * the sink entity was already opened by libv4l2 core.
> +	 */
> +	for (i = 0; i < plugin->pipeline_len - 1; i++) {
> +		entity = pipeline[i].entity;
> +		V4L2_EXYNOS4_DBG("Opening sub-device: %s",
> +				 media_entity_get_info(entity)->name);
> +		ret = v4l2_subdev_open(entity);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +/**
> + * @brief Check if there was a v4l2_ctrl binding defined for the entity
> + * @param entity - media entity.
> + * @param ctrl_id - v4l2 control identifier.
> + *
> + * Check if there was a v4l2-ctrl-binding entry defined for the entity.
> + *
> + * @return true if the binding exists, false otherwise.
> + */
> +static bool has_v4l2_ctrl_binding(struct media_entity *entity,
> +				       int ctrl_id)
> +{
> +	struct v4l2_subdev *sd = media_entity_get_v4l2_subdev(entity);
> +	int i;
> +
> +	if (!sd)
> +		return false;
> +
> +	for (i = 0; i < sd->num_v4l2_ctrl_bindings; ++i)
> +		if (sd->v4l2_ctrl_bindings[i] == ctrl_id)
> +			return true;
> +
> +	return false;
> +}
> +
> +/**
> + * @brief Get the first pipeline entity with matching v4l2-ctrl-binding.
> + * @param plugin - this plugin.
> + * @param cid - v4l2-control identifier.
> + *
> + * Get the first pipeline entity for which v4l2-control-binding
> + * with given cid was defined.
> + *
> + * @return associated entity if defined, or NULL if no matching
> + *         v4l2-ctrl-binding was defined for any entity
> + *         in the pipeline.
> + */
> +static struct media_entity *get_pipeline_entity_by_cid(
> +				struct exynos4_camera_plugin *plugin,
> +				int cid)
> +{
> +	struct pipeline_entity *pipeline = plugin->pipeline;
> +	struct media_entity *entity;
> +	unsigned int i;
> +
> +	if (pipeline == NULL)
> +		return NULL;
> +
> +	for (i = 0; i < plugin->pipeline_len; i++) {
> +		entity = pipeline[i].entity;
> +		if (has_v4l2_ctrl_binding(entity, cid))
> +			return entity;
> +	}
> +
> +	return NULL;
> +}
> +
> +/**
> + * @brief Check if the entity is of capture type
> + * @param entity_name - name of the entity to check
> + *
> + * Check if the entity name ends with a "capture", which
> + * gives a hint that it is of capture type.
> + *
> + * @return True if the entity name ends with a "capture"
> + *         string, and false otherwise.
> + */
> +static bool is_capture_entity(const char *entity_name)
> +{
> +	const char capture_segment[] = "capture";
> +	int cap_segment_pos;
> +
> +	if (entity_name == NULL)
> +		return false;
> +
> +	cap_segment_pos = strlen(entity_name) - strlen(capture_segment);
> +
> +	if (strcmp(entity_name + cap_segment_pos, capture_segment) == 0)
> +		return true;
> +
> +	return false;
> +}
> +
> +static __u32 convert_type(__u32 type)
> +{
> +	switch (type) {
> +	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
> +		return V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
> +	default:
> +		return type;
> +	}
> +}
> +
> +/* -----------------------------------------------------------------------------
> + * Ioctl handlers
> + */
> +
> +static int set_fmt_ioctl(struct exynos4_camera_plugin *plugin,
> +				unsigned long int cmd,
> +				struct v4l2_format *arg,
> +				enum v4l2_subdev_format_whence set_mode)
> +{
> +	struct v4l2_format fmt = { 0 };
> +	int ret;
> +
> +	fmt.type = convert_type(arg->type);
> +	if (fmt.type != arg->type) {
> +		fmt.fmt.pix_mp.width = arg->fmt.pix.width;
> +		fmt.fmt.pix_mp.height = arg->fmt.pix.height;
> +		fmt.fmt.pix_mp.pixelformat = arg->fmt.pix.pixelformat;
> +		fmt.fmt.pix_mp.field = arg->fmt.pix.field;
> +		fmt.fmt.pix_mp.colorspace = arg->fmt.pix.colorspace;
> +		fmt.fmt.pix_mp.num_planes = 1;
> +		fmt.fmt.pix_mp.flags = arg->fmt.pix.flags;
> +		fmt.fmt.pix_mp.plane_fmt[0].bytesperline = arg->fmt.pix.bytesperline;
> +		fmt.fmt.pix_mp.plane_fmt[0].sizeimage = arg->fmt.pix.sizeimage;
> +	} else {
> +		fmt = *arg;
> +	}
> +
> +	ret = negotiate_pipeline_fmt(plugin, &fmt);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (set_mode == V4L2_SUBDEV_FORMAT_ACTIVE) {
> +		ret = apply_pipeline_fmt(plugin, &fmt);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	if (fmt.type != arg->type) {
> +		arg->fmt.pix.width = fmt.fmt.pix_mp.width;
> +		arg->fmt.pix.height = fmt.fmt.pix_mp.height;
> +		arg->fmt.pix.pixelformat = fmt.fmt.pix_mp.pixelformat;
> +		arg->fmt.pix.field = fmt.fmt.pix_mp.field;
> +		arg->fmt.pix.colorspace = fmt.fmt.pix_mp.colorspace;
> +		arg->fmt.pix.bytesperline = fmt.fmt.pix_mp.plane_fmt[0].bytesperline;
> +		arg->fmt.pix.sizeimage = fmt.fmt.pix_mp.plane_fmt[0].sizeimage;
> +		arg->fmt.pix.flags = fmt.fmt.pix_mp.flags;
> +	} else {
> +		*arg = fmt;
> +	}
> +
> +	return 0;
> +}
> +
> +static int get_fmt_ioctl(int fd,
> +			 unsigned long int cmd,
> +			 struct v4l2_format *arg)
> +{
> +	struct v4l2_format fmt = { 0 };
> +	int ret;
> +
> +	fmt.type = convert_type(arg->type);
> +
> +	if (fmt.type == arg->type)
> +		return SYS_IOCTL(fd, cmd, arg);
> +
> +	ret = SYS_IOCTL(fd, cmd, &fmt);
> +	if (ret < 0)
> +		return ret;
> +
> +	memset(&arg->fmt.pix, 0, sizeof(arg->fmt.pix));
> +	arg->fmt.pix.width = fmt.fmt.pix_mp.width;
> +	arg->fmt.pix.height = fmt.fmt.pix_mp.height;
> +	arg->fmt.pix.pixelformat = fmt.fmt.pix_mp.pixelformat;
> +	arg->fmt.pix.field = fmt.fmt.pix_mp.field;
> +	arg->fmt.pix.colorspace = fmt.fmt.pix_mp.colorspace;
> +	arg->fmt.pix.bytesperline = fmt.fmt.pix_mp.plane_fmt[0].bytesperline;
> +	arg->fmt.pix.sizeimage = fmt.fmt.pix_mp.plane_fmt[0].sizeimage;
> +	arg->fmt.pix.flags = fmt.fmt.pix_mp.flags;
> +
> +	return ret;
> +}
> +
> +static int buf_ioctl(int fd,
> +		     unsigned long int cmd,
> +		     struct v4l2_buffer *arg)
> +{
> +	struct v4l2_buffer buf = *arg;
> +	struct v4l2_plane plane = { 0 };
> +	int ret;
> +
> +	buf.type = convert_type(arg->type);
> +
> +	if (buf.type == arg->type)
> +		return SYS_IOCTL(fd, cmd, arg);
> +
> +	memcpy(&plane.m, &arg->m, sizeof(plane.m));
> +	plane.length = arg->length;
> +	plane.bytesused = arg->bytesused;
> +
> +	buf.m.planes = &plane;
> +	buf.length = 1;
> +
> +	ret = SYS_IOCTL(fd, cmd, &buf);
> +
> +	arg->index = buf.index;
> +	arg->memory = buf.memory;
> +	arg->flags = buf.flags;
> +	arg->field = buf.field;
> +	arg->timestamp = buf.timestamp;
> +	arg->timecode = buf.timecode;
> +	arg->sequence = buf.sequence;
> +
> +	arg->length = plane.length;
> +	arg->bytesused = plane.bytesused;
> +	memcpy(&arg->m, &plane.m, sizeof(arg->m));
> +
> +	return ret;
> +}
> +
> +static int querycap_ioctl(int fd, struct v4l2_capability *arg)
> +{
> +	int ret;
> +
> +	ret = SYS_IOCTL(fd, VIDIOC_QUERYCAP, arg);
> +	if (ret < 0)
> +		return ret;
> +
> +	arg->device_caps |= V4L2_CAP_VIDEO_CAPTURE;
> +	arg->capabilities |= V4L2_CAP_VIDEO_CAPTURE;
> +
> +	return ret;
> +}
> +
> +int ctrl_ioctl(struct exynos4_camera_plugin *plugin,
> +	       unsigned long int request, struct v4l2_control *arg)
> +{
> +	struct pipeline_entity *pipeline = plugin->pipeline;
> +	struct media_entity *entity;
> +	struct v4l2_control ctrl = *arg;
> +	struct v4l2_queryctrl queryctrl = { 0 };
> +	bool ctrl_found = false;
> +	int i, ret;
> +
> +	if (pipeline == NULL)
> +		return -EINVAL;
> +
> +	/*
> +	 * The control has to be reset to the default value
> +	 * on all of the pipeline entities, prior setting a new
> +	 * value. This is required in cases when the control config
> +	 * is changed between subsequent calls to VIDIOC_S_CTRL,
> +	 * to avoid the situation when a control is set on more
> +	 * than one sub-device.
> +	 */
> +	if (request == VIDIOC_S_CTRL) {
> +		for (i = 0; i < plugin->pipeline_len; i++) {
> +			struct v4l2_control ctrl_def = ctrl;
> +
> +			entity = pipeline[i].entity;
> +
> +			queryctrl.id = ctrl.id;
> +
> +			/* query default control value */
> +			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
> +					VIDIOC_QUERYCTRL, &queryctrl);
> +			if (ret < 0)
> +				continue;
> +
> +			ctrl_found = true;
> +
> +			if (queryctrl.type & V4L2_CTRL_TYPE_BUTTON)
> +				break;
> +
> +			ctrl_def.value = queryctrl.default_value;
> +			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
> +					VIDIOC_S_CTRL, &ctrl_def);
> +			if (ret < 0)
> +				return -EINVAL;
> +		}
> +
> +		if (!ctrl_found) {
> +			ret = -EINVAL;
> +			goto exit;
> +		}
> +	}
> +
> +	entity = get_pipeline_entity_by_cid(plugin, ctrl.id);
> +
> +	if (entity) {
> +		ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
> +				request, &ctrl);
> +	} else {
> +		/* Walk the pipeline until the request succeeds */
> +		ret = -ENOENT;
> +
> +		for (i = 0; i < plugin->pipeline_len; i++) {
> +			entity = pipeline[i].entity;
> +
> +			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
> +					request, &ctrl);
> +			if (!ret)
> +				break;
> +		}
> +	}
> +
> +exit:
> +	*arg = ctrl;
> +
> +	V4L2_EXYNOS4_DBG("%s [id: 0x%8.8x, name: %s, entity: %s] (%d)",
> +			 VIDIOC_CTRL(request), ctrl.id,
> +			 ret ? NULL : queryctrl.name,
> +			 entity ? media_entity_get_info(entity)->name :
> +				  NULL, ret);
> +
> +
> +	return ret;
> +}
> +
> +static int single_ext_ctrl_ioctl(struct exynos4_camera_plugin *plugin,
> +				 unsigned long int request,
> +				 struct v4l2_ext_controls *arg)
> +{
> +	struct pipeline_entity *pipeline = plugin->pipeline;
> +	struct media_entity *entity;
> +	struct v4l2_ext_controls ctrls = *arg;
> +	struct v4l2_ext_control *ctrl = &ctrls.controls[0];
> +	struct v4l2_query_ext_ctrl queryctrl;
> +	bool ctrl_found = 0;
> +	int i, ret = -EINVAL;
> +
> +	/*
> +	 * The control has to be reset to the default value
> +	 * on all of the pipeline entities, prior setting a new
> +	 * value. This is required in cases when the control config
> +	 * is changed between subsequent calls to VIDIOC_S_EXT_CTRLS,
> +	 * to avoid the situation when a control is set on more
> +	 * than one sub-device.
> +	 */
> +	if (request == VIDIOC_S_EXT_CTRLS) {
> +		for (i = 0; i < plugin->pipeline_len; i++) {
> +			struct v4l2_ext_controls ctrls_def = ctrls;
> +			struct v4l2_ext_control *ctrl_def = &ctrls_def.controls[0];
> +
> +			entity = pipeline[i].entity;
> +
> +			queryctrl.id = ctrl->id;
> +
> +			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
> +					VIDIOC_QUERY_EXT_CTRL, &queryctrl);
> +			if (ret < 0)
> +				continue;
> +
> +			ctrl_found = true;
> +
> +			if (queryctrl.type & V4L2_CTRL_TYPE_BUTTON)
> +				break;
> +
> +			ctrl_def->value64 = queryctrl.default_value;
> +
> +			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
> +					VIDIOC_S_EXT_CTRLS, &ctrls_def);
> +			if (ret < 0)
> +				return -EINVAL;
> +		}
> +
> +		if (!ctrl_found) {
> +			ret = -EINVAL;
> +			goto exit;
> +		}
> +	}
> +
> +	entity = get_pipeline_entity_by_cid(plugin, ctrl->id);
> +
> +	if (entity) {
> +		ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
> +				request, &ctrls);
> +	} else {
> +		/* Walk the pipeline until the request succeeds */
> +		for (i = 0; i < plugin->pipeline_len; i++) {
> +			entity = pipeline[i].entity;
> +
> +			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
> +					request, &ctrls);
> +			if (!ret)
> +				break;
> +		}
> +	}
> +
> +exit:
> +	*arg = ctrls;
> +
> +	V4L2_EXYNOS4_DBG("%s [id: 0x%8.8x, name: %s, entity: %s] (%d)",
> +			 VIDIOC_CTRL(request), ctrl->id,
> +			 ret ? NULL : queryctrl.name,
> +			 entity ? media_entity_get_info(entity)->name :
> +				  NULL, ret);
> +
> +	return ret;
> +}
> +
> +int ext_ctrl_ioctl(struct exynos4_camera_plugin *plugin,
> +		   unsigned long int request,
> +		   struct v4l2_ext_controls *arg)
> +{
> +	struct v4l2_ext_controls out_ctrls = *arg, ctrls = *arg;
> +	int ret = -EINVAL, i;
> +
> +	ctrls.count = 1;
> +
> +	/*
> +	 * Split cluster to individual ioctl calls for each control
> +	 * from the array, to make possible redirection of every
> +	 * single control to different sub-device, according to the
> +	 * configuration settings.
> +	 */
> +	for (i = 0; i < arg->count; ++i) {
> +		ctrls.controls = &arg->controls[i];
> +
> +		ret = single_ext_ctrl_ioctl(plugin, request, &ctrls);
> +		out_ctrls.controls[i] = ctrls.controls[i];
> +		if (ret < 0) {
> +			if (ctrls.error_idx == 1)
> +				out_ctrls.error_idx = ctrls.count;
> +			else
> +				out_ctrls.error_idx = i;
> +			break;
> +		}
> +	}
> +
> +	*arg = out_ctrls;
> +	return ret;
> +}
> +
> +int sort_ctrls(const void * a, const void * b)
> +{
> +	const struct media_entity_to_cid *ctrl_a = a, *ctrl_b = b;
> +
> +	return ctrl_a->queryctrl.id - ctrl_b->queryctrl.id;
> +}
> +
> +int queryctrl_ioctl(struct exynos4_camera_plugin *plugin,
> +		    struct v4l2_queryctrl *arg)
> +{
> +	struct pipeline_entity *pipeline = plugin->pipeline;
> +	struct media_entity *entity, *target_entity;
> +	struct v4l2_queryctrl queryctrl = *arg;
> +	struct media_entity_to_cid *ctrls_found;
> +	int i, ret = -EINVAL, num_ctrls = 0;
> +
> +	/*
> +	 * If id is or'ed with V4L2_CTRL_FLAG_NEXT_CTRL then the control to
> +	 * be found is the one with the next lowest id among all entities
> +	 * in the pipeline.
> +	 */
> +	if (queryctrl.id & V4L2_CTRL_FLAG_NEXT_CTRL) {
> +		ctrls_found = malloc(sizeof(*ctrls_found));
> +
> +		for (i = 0; i < plugin->pipeline_len; i++) {
> +			entity = pipeline[i].entity;
> +
> +			queryctrl = *arg;
> +
> +			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
> +					VIDIOC_QUERYCTRL, &queryctrl);
> +			if (!ret) {
> +				ctrls_found = realloc(ctrls_found,
> +					sizeof(*ctrls_found) * (num_ctrls + 1));
> +				ctrls_found[num_ctrls].queryctrl = queryctrl;
> +				ctrls_found[num_ctrls].entity = entity;
> +				++num_ctrls;
> +			}
> +		}
> +
> +		if (num_ctrls == 0) {
> +			ret = -EINVAL;
> +			entity = NULL;
> +			goto done;
> +		}
> +
> +		qsort(ctrls_found, num_ctrls, sizeof(*ctrls_found), sort_ctrls);
> +
> +		queryctrl = ctrls_found[0].queryctrl;
> +		target_entity = ctrls_found[0].entity;
> +
> +		free(ctrls_found);
> +	}
> +
> +	entity = get_pipeline_entity_by_cid(plugin, queryctrl.id);
> +	if (entity)
> +		target_entity = entity;
> +
> +	ret = SYS_IOCTL(media_entity_get_v4l2_subdev(target_entity)->fd,
> +			VIDIOC_QUERYCTRL, &queryctrl);
> +
> +done:
> +	V4L2_EXYNOS4_DBG(
> +		"VIDIOC_QUERYCTRL [id: 0x%8.8x, name: %s, entity: %s] (%d)",
> +		ret ? arg->id : queryctrl.id, ret ? NULL : queryctrl.name,
> +		target_entity ? media_entity_get_info(target_entity)->name :
> +				NULL, ret);
> +
> +	*arg = queryctrl;
> +
> +	return ret;
> +}
> +
> +int query_ext_ctrl_ioctl(struct exynos4_camera_plugin *plugin,
> +			 struct v4l2_query_ext_ctrl *arg)
> +{
> +	struct pipeline_entity *pipeline = plugin->pipeline;
> +	struct media_entity *entity, *target_entity;
> +	struct v4l2_query_ext_ctrl query_ext_ctrl = *arg;
> +	struct media_entity_to_cid *ctrls_found;
> +	int i, ret = -EINVAL, num_ctrls = 0;
> +
> +	/*
> +	 * If id is or'ed with V4L2_CTRL_FLAG_NEXT_CTRL then the control to
> +	 * be found is the one with the next lowest id among all entities
> +	 * in the pipeline.
> +	 */
> +	if (query_ext_ctrl.id & V4L2_CTRL_FLAG_NEXT_CTRL) {
> +		ctrls_found = malloc(sizeof(*ctrls_found));
> +
> +		for (i = 0; i < plugin->pipeline_len; i++) {
> +			entity = pipeline[i].entity;
> +
> +			query_ext_ctrl = *arg;
> +
> +			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
> +					VIDIOC_QUERY_EXT_CTRL, &query_ext_ctrl.id);
> +			if (!ret) {
> +				ctrls_found = realloc(ctrls_found,
> +					sizeof(*ctrls_found) * (num_ctrls + 1));
> +				ctrls_found[num_ctrls].query_ext_ctrl =
> +								query_ext_ctrl;
> +				ctrls_found[num_ctrls].entity = entity;
> +				++num_ctrls;
> +			}
> +		}
> +
> +		if (num_ctrls == 0) {
> +			ret = -EINVAL;
> +			entity = NULL;
> +			goto done;
> +		}
> +
> +		qsort(ctrls_found, num_ctrls, sizeof(*ctrls_found), sort_ctrls);
> +
> +		query_ext_ctrl = ctrls_found[0].query_ext_ctrl;
> +		target_entity = ctrls_found[0].entity;
> +
> +		free(ctrls_found);
> +	}
> +
> +	entity = get_pipeline_entity_by_cid(plugin, query_ext_ctrl.id);
> +	if (entity)
> +		target_entity = entity;
> +
> +	ret = SYS_IOCTL(media_entity_get_v4l2_subdev(target_entity)->fd,
> +			VIDIOC_QUERYCTRL, &query_ext_ctrl);
> +
> +done:
> +	V4L2_EXYNOS4_DBG(
> +		"VIDIOC_QUERY_EXT_CTRL [id: 0x%8.8x, name: %s, entity: %s] (%d)",
> +		ret ? arg->id : query_ext_ctrl.id,
> +		ret ? NULL : query_ext_ctrl.name,
> +		target_entity ? media_entity_get_info(target_entity)->name :
> +				NULL, ret);
> +
> +	*arg = query_ext_ctrl;
> +
> +	return ret;
> +}
> +
> +int querymenu_ioctl(struct exynos4_camera_plugin *plugin,
> +		    struct v4l2_querymenu *arg)

static? I presume a lot of the other functions should be static as well.

> +{
> +	struct pipeline_entity *pipeline = plugin->pipeline;
> +	struct media_entity *entity;
> +	struct v4l2_querymenu querymenu = *arg;
> +	int i, ret = -EINVAL;
> +
> +	entity = get_pipeline_entity_by_cid(plugin, querymenu.id);
> +	if (entity) {
> +		ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
> +			        VIDIOC_QUERYMENU, &querymenu);
> +		goto exit;
> +	}
> +
> +	for (i = 0; i < plugin->pipeline_len; i++) {
> +		entity = pipeline[i].entity;
> +
> +		ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
> +				VIDIOC_QUERYMENU, &querymenu);
> +		if (!ret)
> +			break;
> +	}
> +
> +exit:
> +	*arg = querymenu;
> +
> +	V4L2_EXYNOS4_DBG(
> +		"VIDIOC_QUERYMENU [id: 0x%8.8x, name: %s, entity: %s] (%d)",
> +		querymenu.id, ret ? NULL : querymenu.name,
> +		entity ? media_entity_get_info(entity)->name : NULL, ret);
> +
> +	return ret;
> +}
> +
> +static void *plugin_init(int fd)
> +{
> +	struct v4l2_capability cap = { 0 };
> +	struct exynos4_camera_plugin *plugin = NULL;
> +	const char *sink_entity_name;
> +	struct media_device *media;
> +	struct media_entity *sink_entity;
> +	int ret;
> +
> +	ret = SYS_IOCTL(fd, VIDIOC_QUERYCAP, &cap);
> +	if (ret < 0) {
> +		V4L2_EXYNOS4_ERR("Failed to query video capabilities.");
> +		return NULL;
> +	}
> +
> +	/* Check if this is Exynos4 media device */
> +	if (strcmp((char *) cap.driver, EXYNOS4_FIMC_DRV) &&
> +	    strcmp((char *) cap.driver, EXYNOS4_FIMC_LITE_DRV) &&
> +	    strcmp((char *) cap.driver, EXYNOS4_FIMC_IS_ISP_DRV)) {
> +		V4L2_EXYNOS4_ERR("Not an Exynos4 media device.");
> +		return NULL;
> +	}
> +
> +	/*
> +	 * Create a representation of the media device
> +	 * containing the opened video device.
> +	 */
> +	media = media_device_new_by_subdev_fd(fd, &sink_entity);
> +	if (media == NULL) {
> +		V4L2_EXYNOS4_ERR("Failed to create media device.");
> +		return NULL;
> +	}
> +
> +#ifdef DEBUG
> +	media_debug_set_handler(media, (void (*)(void *, ...))fprintf, stdout);
> +#endif
> +
> +	sink_entity_name = media_entity_get_info(sink_entity)->name;
> +
> +	/* Check if video entity is of capture type, not m2m */
> +	if (!is_capture_entity(sink_entity_name)) {
> +		V4L2_EXYNOS4_ERR("Device not of capture type.");
> +		goto err_get_sink_entity;
> +	}
> +
> +	/*
> +	 * Initialize sink_entity subdev fd with the one opened
> +	 * by the libv4l core to avoid losing it on pipeline opening.
> +	 */
> +	v4l2_subdev_create_opened(sink_entity, fd);
> +
> +	/* Parse media configuration file and apply its settings */
> +	ret = mediatext_parse_setup_config(media, EXYNOS4_CAPTURE_CONF);
> +	if (ret < 0) {
> +		V4L2_EXYNOS4_ERR("Media config parser error.");
> +		goto err_get_sink_entity;
> +	}
> +
> +	/* Allocate private data */
> +	plugin = calloc(1, sizeof(*plugin));
> +	if (!plugin)
> +		goto err_get_sink_entity;
> +
> +	plugin->media = media;
> +
> +	/*
> +	 * Discover the pipeline of sub-devices from a camera sensor
> +	 * to the opened video device.
> +	 */
> +	ret = discover_pipeline_by_entity(plugin, sink_entity);
> +	if (ret < 0) {
> +		V4L2_EXYNOS4_ERR("Error discovering video pipeline.");
> +		goto err_discover_pipeline;
> +	}
> +
> +	/* Open all sub-devices in the discovered pipeline */
> +	ret = open_pipeline(plugin);
> +	if (ret < 0) {
> +		V4L2_EXYNOS4_ERR("Error opening video pipeline.");
> +		goto err_discover_pipeline;
> +	}
> +
> +	V4L2_EXYNOS4_LOG("Initialized exynos4-camera plugin.");
> +
> +	return plugin;
> +
> +err_discover_pipeline:
> +	free(plugin);
> +err_get_sink_entity:
> +	if (media)
> +		media_device_unref(media);
> +	return NULL;
> +}
> +
> +static void plugin_close(void *dev_ops_priv)
> +{
> +	struct exynos4_camera_plugin *plugin = dev_ops_priv;
> +
> +	if (plugin == NULL)
> +		return;
> +
> +	media_device_unref(plugin->media);
> +
> +	free(plugin);
> +}
> +
> +static int plugin_ioctl(void *dev_ops_priv, int fd, unsigned long int cmd,
> +			void *arg)
> +{
> +	struct exynos4_camera_plugin *plugin = dev_ops_priv;
> +
> +	if (plugin == NULL || arg == NULL)
> +		return -EINVAL;
> +
> +	switch (cmd) {
> +	case VIDIOC_S_CTRL:
> +	case VIDIOC_G_CTRL:
> +		return ctrl_ioctl(plugin, cmd, arg);
> +	case VIDIOC_S_EXT_CTRLS:
> +	case VIDIOC_G_EXT_CTRLS:
> +	case VIDIOC_TRY_EXT_CTRLS:
> +		return ext_ctrl_ioctl(plugin, cmd, arg);
> +	case VIDIOC_QUERYCTRL:
> +		return queryctrl_ioctl(plugin, arg);
> +	case VIDIOC_QUERY_EXT_CTRL:
> +		return query_ext_ctrl_ioctl(plugin, arg);
> +	case VIDIOC_QUERYMENU:
> +		return querymenu_ioctl(plugin, arg);
> +	case VIDIOC_TRY_FMT:
> +		return set_fmt_ioctl(plugin, cmd, arg,
> +				     V4L2_SUBDEV_FORMAT_TRY);
> +	case VIDIOC_S_FMT:
> +		return set_fmt_ioctl(plugin, cmd, arg,
> +				     V4L2_SUBDEV_FORMAT_ACTIVE);
> +	case VIDIOC_G_FMT:
> +		return get_fmt_ioctl(fd, cmd, arg);
> +	case VIDIOC_QUERYCAP:
> +		return querycap_ioctl(fd, arg);
> +	case VIDIOC_QBUF:
> +	case VIDIOC_DQBUF:
> +	case VIDIOC_QUERYBUF:
> +	case VIDIOC_PREPARE_BUF:
> +		return buf_ioctl(fd, cmd, arg);
> +	case VIDIOC_REQBUFS:
> +		return SIMPLE_CONVERT_IOCTL(fd, cmd, arg,
> +					    v4l2_requestbuffers);
> +	case VIDIOC_ENUM_FMT:
> +		return SIMPLE_CONVERT_IOCTL(fd, cmd, arg, v4l2_fmtdesc);
> +	case VIDIOC_CROPCAP:
> +		return SIMPLE_CONVERT_IOCTL(fd, cmd, arg, v4l2_cropcap);
> +	case VIDIOC_STREAMON:
> +	case VIDIOC_STREAMOFF:
> +		{
> +			int *arg_type = (int *) arg;
> +			__u32 type;
> +
> +			type = convert_type(*arg_type);
> +
> +			if (type != V4L2_BUF_TYPE_VIDEO_CAPTURE &&
> +			    type != V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE) {
> +				V4L2_EXYNOS4_ERR("Invalid buffer type.");
> +				return -EINVAL;
> +			}
> +
> +			return SYS_IOCTL(fd, cmd, &type);
> +		}
> +
> +	default:
> +		return SYS_IOCTL(fd, cmd, arg);
> +	}
> +}
> +
> +PLUGIN_PUBLIC const struct libv4l_dev_ops libv4l2_plugin = {
> +	.init = &plugin_init,
> +	.close = &plugin_close,
> +	.ioctl = &plugin_ioctl,
> +};

Jacek Anaszewski Nov. 24, 2016, 4:14 p.m. UTC | #2

Hi Sakari,

On 11/24/2016 04:11 PM, Sakari Ailus wrote:
> Hi Jacek,
>
> Thank you for your continued work on the Exynos plugin patchset!
>
> I think we're pretty close to being able to merge the set, if you could
> still bear with me awhile. :-)

Your demanding reviewer I must admit. :-)
Of course, I appreciate all your remarks, they're highly valuable.

> On Wed, Oct 12, 2016 at 04:35:22PM +0200, Jacek Anaszewski wrote:
> ...
>> diff --git a/lib/libv4l-exynos4-camera/Makefile.am b/lib/libv4l-exynos4-camera/Makefile.am
>> new file mode 100644
>> index 0000000..c38b7f6
>> --- /dev/null
>> +++ b/lib/libv4l-exynos4-camera/Makefile.am
>> @@ -0,0 +1,19 @@
>> +if WITH_V4L_PLUGINS
>> +libv4l2plugin_LTLIBRARIES = libv4l-exynos4-camera.la
>> +endif
>> +
>> +media-bus-format-names.h: ../../include/linux/media-bus-format.h
>> +	sed -e '/#define MEDIA_BUS_FMT/ ! d; s/.*FMT_//; /FIXED/ d; s/\t.*//; s/.*/{ \"&\", MEDIA_BUS_FMT_& },/;' \
>> +	< $< > $@
>> +
>> +media-bus-format-codes.h: ../../include/linux/media-bus-format.h
>> +	sed -e '/#define MEDIA_BUS_FMT/ ! d; s/.*#define //; /FIXED/ d; s/\t.*//; s/.*/ &,/;' \
>> +	< $< > $@
>> +
>> +BUILT_SOURCES = media-bus-format-names.h media-bus-format-codes.h
>> +CLEANFILES = $(BUILT_SOURCES)
>
> It'd be nice to be able to use the same generated headers that now are under
> utils/media-ctl, instead of copying the sed script here in verbatim. If the
> script is changed or fixed in some way, the other location probably will
> remain unchanged...

The problem is that those headers are built after this plugin.

> I wonder if there's a proper way to generate build time headers such as
> these.
>
> Another less good alternative would be to put these into a separate Makefile
> and include that Makefile where the headers are needed. But I don't like
> that much either, it's a hack.

In this case it seems to be the only feasible optimization.

>> +
>> +nodist_libv4l_exynos4_camera_la_SOURCES = $(BUILT_SOURCES)
>> +libv4l_exynos4_camera_la_SOURCES = libv4l-exynos4-camera.c ../../utils/media-ctl/libmediactl.c ../../utils/media-ctl/libv4l2subdev.c ../../utils/media-ctl/mediatext.c
>> +libv4l_exynos4_camera_la_CFLAGS = -fvisibility=hidden -std=gnu99
>> +libv4l_exynos4_camera_la_LDFLAGS = -avoid-version -module -shared -export-dynamic -lpthread
>> diff --git a/lib/libv4l-exynos4-camera/libv4l-exynos4-camera.c b/lib/libv4l-exynos4-camera/libv4l-exynos4-camera.c
>> new file mode 100644
>> index 0000000..c219fe5
>> --- /dev/null
>> +++ b/lib/libv4l-exynos4-camera/libv4l-exynos4-camera.c
>> @@ -0,0 +1,1325 @@
>> +/*
>> + * Copyright (c) 2016 Samsung Electronics Co., Ltd.
>> + *              http://www.samsung.com
>> + *
>> + * Author: Jacek Anaszewski <[e-mail]>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU Lesser General Public License as published by
>> + * the Free Software Foundation; either version 2.1 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> + * Lesser General Public License for more details.
>> + */
>> +
>> +#include <config.h>
>> +#include <errno.h>
>> +#include <linux/types.h>
>> +#include <stdbool.h>
>> +#include <stdint.h>
>> +#include <stdio.h>
>> +#include <stdlib.h>
>> +#include <string.h>
>> +#include <sys/ioctl.h>
>> +#include <sys/syscall.h>
>> +#include <unistd.h>
>> +
>> +#include "../../utils/media-ctl/mediactl.h"
>> +#include "../../utils/media-ctl/mediatext.h"
>> +#include "../../utils/media-ctl/v4l2subdev.h"
>> +#include "libv4l-plugin.h"
>> +
>> +#ifdef DEBUG
>> +#define V4L2_EXYNOS4_DBG(format, ARG...)\
>> +	printf("[%s:%d] [%s] " format " \n", __FILE__, __LINE__, __func__, ##ARG)
>> +#else
>> +#define V4L2_EXYNOS4_DBG(format, ARG...)
>> +#endif
>> +
>> +#define V4L2_EXYNOS4_ERR(format, ARG...)\
>> +	fprintf(stderr, "Libv4l Exynos4 camera plugin: "format "\n", ##ARG)
>> +
>> +#define V4L2_EXYNOS4_LOG(format, ARG...)\
>> +	fprintf(stdout, "Libv4l Exynos4 camera plugin: "format "\n", ##ARG)
>> +
>> +#define VIDIOC_CTRL(type)				\
>> +	((type) == VIDIOC_S_CTRL ? "VIDIOC_S_CTRL" :	\
>> +				   "VIDIOC_G_CTRL")
>> +
>> +#if HAVE_VISIBILITY
>> +#define PLUGIN_PUBLIC __attribute__ ((visibility("default")))
>> +#else
>> +#define PLUGIN_PUBLIC
>> +#endif
>> +
>> +#define SYS_IOCTL(fd, cmd, arg) \
>> +	syscall(SYS_ioctl, (int)(fd), (unsigned long)(cmd), (void *)(arg))
>> +
>> +#define SIMPLE_CONVERT_IOCTL(fd, cmd, arg, __struc) ({  \
>> +	int __ret;                                      \
>> +	struct __struc *req = arg;                      \
>> +	uint32_t type = req->type;                      \
>> +	req->type = convert_type(type);                 \
>> +	__ret = SYS_IOCTL(fd, cmd, arg);                \
>> +	req->type = type;                               \
>> +	__ret;                                          \
>> +	})
>> +
>> +#ifndef min
>> +#define min(a, b) (((a) < (b)) ? (a) : (b))
>> +#endif
>> +
>> +#ifndef max
>> +#define max(a, b) (((a) > (b)) ? (a) : (b))
>> +#endif
>> +
>> +#define EXYNOS4_FIMC_DRV	"exynos4-fimc"
>> +#define EXYNOS4_FIMC_LITE_DRV	"exynos-fimc-lit"
>> +#define EXYNOS4_FIMC_IS_ISP_DRV	"exynos4-fimc-is"
>> +#define EXYNOS4_CAPTURE_CONF	"/var/lib/libv4l/exynos4_capture_conf"
>
> Is this something that should be configurable in ./configure?

OK.

>
>> +#define EXYNOS4_FIMC_IS_ISP	"FIMC-IS-ISP"
>> +#define EXYNOS4_S5K6A3		"S5K6A3"
>
> Maybe this one as well. But it could come from a configuration file, too.

Right, the sensor is independent of SoC.

>
> The problem at large is actually something else: how do you recognise the
> hardware you're running on?
>
> You could find the sensor by walking the media graph.
>
> But if you need to know something very hardware specific it might not be
> available through the generic interfaces, and you might need to know the
> exact hardware you have.
>
> How do you know that you should load a particular plugin? I wonder if we
> could add a small snippet of code to detect different kinds of systems, I
> presume this is the plugin you want to load if the user has opened a video
> node of the Exynos4 ISP; you could find through the Media controller.

This code snippet in plugin_init() detects if we are on Exynos4 media
device:

         ret = SYS_IOCTL(fd, VIDIOC_QUERYCAP, &cap);
         if (ret < 0) {
                 V4L2_EXYNOS4_ERR("Failed to query video capabilities.");
                 return NULL;
         }

         /* Check if this is Exynos4 media device */
         if (strcmp((char *) cap.driver, EXYNOS4_FIMC_DRV) &&
             strcmp((char *) cap.driver, EXYNOS4_FIMC_LITE_DRV) &&
             strcmp((char *) cap.driver, EXYNOS4_FIMC_IS_ISP_DRV)) {
                 V4L2_EXYNOS4_ERR("Not an Exynos4 media device.");
                 return NULL;
         }

Additionally I check if this is capture and not m2m device:

         /* Check if video entity is of capture type, not m2m */
         if (!is_capture_entity(sink_entity_name)) {
                 V4L2_EXYNOS4_ERR("Device not of capture type.");
                 goto err_get_sink_entity;
         }



>
> That's certainly out of scope of the patchset, I just thought of binging up
> the topics for discussion. :-)
>
>> +#define EXYNOS4_FIMC_LITE_PREFIX "FIMC-LITE."
>> +#define EXYNOS4_FIMC_PREFIX	"FIMC."
>> +#define EXYNOS4_MAX_FMT_NEGO_NUM 50
>> +#define EXYNOS4_MAX_PIPELINE_LEN 7
>> +
>> +struct media_device;
>> +struct media_entity;
>> +
>> +/*
>> + * struct pipeline_entity - linked media device pipeline
>> + * @entity:		linked entity
>> + * @sink_pad:		inbound link pad of the entity
>> + * @src_pad:		outbound link pad of the entity
>> + */
>> +struct pipeline_entity {
>> +	struct media_entity *entity;
>> +	struct media_pad *sink_pad;
>> +	struct media_pad *src_pad;
>> +};
>> +
>> +/*
>> + * struct media_entity_to_cid - entity to control map
>> + * @entity:		media entity
>> + * @sink_pad:		inbound link pad of the entity
>> + * @src_pad:		outbound link pad of the entity
>> + */
>> +struct media_entity_to_cid {
>> +	struct media_entity *entity;
>> +	union {
>> +		struct v4l2_queryctrl queryctrl;
>> +		struct v4l2_query_ext_ctrl query_ext_ctrl;
>> +	};
>> +};
>> +
>> +/*
>> + * struct exynos4_camera_plugin - libv4l exynos4 camera plugin
>> + * @media:		media device comprising the opened video device
>> + * @pipeline:		video pipeline, element 0 is the source entity
>> + * @pipeline_len:	length of the video pipeline
>> + */
>> +struct exynos4_camera_plugin {
>
> static?

Right.

>> +	struct media_device *media;
>> +	struct pipeline_entity pipeline[EXYNOS4_MAX_PIPELINE_LEN];
>> +	unsigned int pipeline_len;
>> +};
>> +
>> +/* -----------------------------------------------------------------------------
>> + * Pipeline operations
>> + */
>> +
>> +/**
>> + * @brief Discover video pipeline for given sink entity
>> + * @param plugin - this plugin.
>> + * @param entity - sink entity of the pipeline.
>> + *
>> + * Discover the video pipeline, by walking starting from the
>> + * sink entity upwards until a source entity is encountered.
>> + *
>> + * @return 0 if the sensor entity was detected,
>> + * 	   or negative error code on failure.
>> + */
>> +static int discover_pipeline_by_entity(struct exynos4_camera_plugin *plugin,
>> +				       struct media_entity *entity)
>> +{
>> +	struct pipeline_entity reverse_pipeline[EXYNOS4_MAX_PIPELINE_LEN];
>> +	struct media_pad *src_pad;
>> +	struct media_link *link = NULL, *backlinks[2];
>> +	unsigned int num_backlinks, cur_pipe_pos = 0;
>> +	int i, j;
>> +	int ret;
>> +
>> +	if (entity == NULL)
>> +		return -EINVAL;
>> +
>> +	for (;;) {
>> +		/* Cache the recently discovered entity. */
>> +		reverse_pipeline[cur_pipe_pos].entity = entity;
>> +
>> +		/* Cache the source pad used for linking the entity. */
>> +		if (link)
>> +			reverse_pipeline[cur_pipe_pos].src_pad = link->source;
>> +
>> +		ret = media_entity_get_backlinks(entity, backlinks,
>> +						 &num_backlinks);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		/* Check if pipeline source entity has been reached. */
>> +		if (num_backlinks > 2) {
>> +			V4L2_EXYNOS4_DBG("Unexpected number of busy sink pads (%d)",
>> +					 num_backlinks);
>> +			return -EINVAL;
>> +		} else if (num_backlinks == 2) {
>> +			/*
>> +			 * Allow two active pads only in case of
>> +			 * S5C73M3-OIF entity.
>> +			 */
>> +			if (strcmp(media_entity_get_info(entity)->name,
>> +				   "S5C73M3-OIF")) {
>> +				V4L2_EXYNOS4_DBG("Ambiguous media device topology: "
>> +						 "two busy sink pads");
>> +				return -EINVAL;
>> +			}
>> +			/*
>> +			 * Two active links are allowed betwen S5C73M3-OIF and
>> +			 * S5C73M3 entities. In such a case route through the
>> +			 * pad with id == 0 has to be chosen.
>> +			 */
>> +			link = NULL;
>> +			for (i = 0; i < num_backlinks; i++)
>> +				if (backlinks[i]->sink->index == 0)
>> +					link = backlinks[i];
>> +			if (link == NULL)
>> +				return -EINVAL;
>> +		} else if (num_backlinks == 1) {
>> +			link = backlinks[0];
>> +		} else {
>> +			reverse_pipeline[cur_pipe_pos].sink_pad = NULL;
>> +			break;
>> +		}
>> +
>> +		/* Cache the sink pad used for linking the entity. */
>> +		reverse_pipeline[cur_pipe_pos].sink_pad = link->sink;
>> +
>> +		V4L2_EXYNOS4_DBG("Discovered sink pad %d for the %s entity",
>> +				 reverse_pipeline[cur_pipe_pos].sink_pad->index,
>> +				 media_entity_get_info(entity)->name);
>> +
>> +		src_pad = media_entity_remote_source(link->sink);
>> +		if (!src_pad)
>> +			return -EINVAL;
>> +
>> +		entity = src_pad->entity;
>> +		if (++cur_pipe_pos == EXYNOS4_MAX_PIPELINE_LEN)
>> +			return -EINVAL;
>> +	}
>> +
>> +	/*
>> +	 * Reorder discovered pipeline elements so that the sensor
>> +	 * entity was the pipeline head.
>> +	 */
>> +	j = 0;
>> +	for (i = cur_pipe_pos; i >= 0; i--)
>
> How about:
>
> 	for (i = cur_pipe_pos, j = 0; i >= 0; i--, j++)
>
> And you can avoid setting j to zero outside the loop plus incrementing j++
> where it doesn't seem to fit too well.

I was thinking about it, but finally decided that this arrangement
will improve readability. Nothing prevents us to apply the
optimizations you've just suggested though.

>> +		plugin->pipeline[j++] = reverse_pipeline[i];
>> +
>> +	plugin->pipeline_len = j;
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * @brief Check if the entity belongs to the plugin video pipeline
>> + * @param plugin - this plugin.
>> + * @param entity_name - name of the entity to look for.
>> + *
>> + * Check if the entity belongs to the pipeline whose sink element
>> + * is the video device represented by the file descriptor passed
>> + * to plugin_init().
>> + *
>> + * @return True if the entity belongs to the pipeline,
>> + *         and false otherwise.
>> + */
>> +static bool has_pipeline_entity(struct exynos4_camera_plugin *plugin,
>> +				char *entity_name)
>> +{
>> +	struct pipeline_entity *pipeline = plugin->pipeline;
>> +	struct media_entity *entity;
>> +	unsigned int i;
>> +
>> +	if (pipeline == NULL || entity_name == NULL)
>> +		return -EINVAL;
>> +
>> +	for (i = 0; i < plugin->pipeline_len; i++) {
>> +		entity = pipeline[i].entity;
>> +		if (!strncmp(media_entity_get_info(entity)->name, entity_name,
>> +			     strlen(entity_name)))
>> +			return true;
>> +	}
>> +
>> +	return false;
>> +}
>> +
>> +/**
>> + * @brief Adjust mbus format to FIMC_IS_ISP limitations.
>> + * @param mbus_fmt - format to adjust.
>> + *
>> + * FIMC_IS_ISP shears the video frame off, effectively the format set
>> + * on the preceding entities has to be suitably greater to achieve
>> + * the frame size requested by the user.
>> + *
>> + * Also the miminum frame size supported by FIMC_IS_ISP is 128x128.
>> + */
>> +static void adjust_format_to_fimc_is_isp(struct v4l2_mbus_framefmt *mbus_fmt)
>> +{
>> +	mbus_fmt->width = max(128, mbus_fmt->width);
>> +	mbus_fmt->height = max(128, mbus_fmt->height);
>> +
>> +	mbus_fmt->width += 16;
>> +	mbus_fmt->height += 12;
>> +}
>> +
>> +/**
>> + * @brief Negotiate format acceptable for all pipeline entities.
>> + * @param plugin - this plugin.
>> + * @param dev_fmt - requested video device format.
>> + *
>> + * Negotiate common format acceptable by all the pipeline entities,
>> + * that is closest to the requested one.
>> + *
>> + * @return 0 if the negotiation succeeded,
>> + * 	   or negative error code on failure.
>> + */
>> +static int negotiate_pipeline_fmt(struct exynos4_camera_plugin *plugin,
>> +				  struct v4l2_format *dev_fmt)
>> +{
>> +	struct v4l2_mbus_framefmt mbus_fmt = { 0 }, common_fmt;
>> +	int repeat_negotiation, cnt_negotiation = 0, ret, pad_id, i;
>> +	struct pipeline_entity *pipeline = plugin->pipeline;
>> +	enum v4l2_subdev_fmt_mismatch fmt_err;
>> +	struct media_entity *entity;
>> +
>> +	if (pipeline == NULL || dev_fmt == NULL)
>> +		return -EINVAL;
>> +
>> +	mbus_fmt.width = dev_fmt->fmt.pix_mp.width;
>> +	mbus_fmt.height = dev_fmt->fmt.pix_mp.height;
>> +	mbus_fmt.field = dev_fmt->fmt.pix_mp.field;
>> +	mbus_fmt.colorspace = dev_fmt->fmt.pix_mp.colorspace;
>> +
>> +	if (has_pipeline_entity(plugin, EXYNOS4_FIMC_IS_ISP))
>> +		adjust_format_to_fimc_is_isp(&mbus_fmt);
>> +
>> +	V4L2_EXYNOS4_DBG("Begin pipeline format negotiation...");
>> +
>> +	for (;;) {
>> +		repeat_negotiation = 0;
>> +		entity = pipeline[0].entity;
>> +
>> +		pad_id = pipeline[0].src_pad->index;
>> +
>> +		V4L2_EXYNOS4_DBG("Setting format on the source entity pad %s:%d",
>> +				 media_entity_get_info(entity)->name, pad_id);
>> +
>> +		ret = v4l2_subdev_set_format(entity, &mbus_fmt,
>> +					     pad_id, V4L2_SUBDEV_FORMAT_TRY);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		V4L2_EXYNOS4_DBG("Format set on the pad %s:%d: mcode: %s, cs: %s, w: %d, h: %d",
>> +				 media_entity_get_info(entity)->name, pad_id,
>> +				 v4l2_subdev_pixelcode_to_string(mbus_fmt.code),
>> +				 v4l2_subdev_colorspace_to_string(mbus_fmt.colorspace),
>> +				 mbus_fmt.width, mbus_fmt.height);
>> +
>> +		common_fmt = mbus_fmt;
>> +
>> +		/* Stop iterating on last but one entity as it is not a sub-device. */
>> +		for (i = 1; i < plugin->pipeline_len - 1; i++) {
>> +			entity = pipeline[i].entity;
>> +
>> +			pad_id = pipeline[i].sink_pad->index;
>> +
>> +			V4L2_EXYNOS4_DBG("Setting format on the pad %s:%d: mcode: %s, cs: %s, w: %d, h: %d",
>> +					 media_entity_get_info(entity)->name, pad_id,
>> +					 v4l2_subdev_pixelcode_to_string(mbus_fmt.code),
>> +					 v4l2_subdev_colorspace_to_string(mbus_fmt.colorspace),
>> +					 mbus_fmt.width, mbus_fmt.height);
>> +
>> +			/* Set format on the entity sink pad. */
>> +			ret = v4l2_subdev_set_format(entity, &mbus_fmt, pad_id,
>> +							V4L2_SUBDEV_FORMAT_TRY);
>> +			if (ret < 0)
>> +				return ret;
>> +
>> +			fmt_err = v4l2_subdev_format_compare(&mbus_fmt, &common_fmt);
>> +			if (fmt_err) {
>> +				if (fmt_err == FMT_MISMATCH_WIDTH &&
>> +				     !strncmp(media_entity_get_info(entity)->name,
>> +					      EXYNOS4_FIMC_LITE_PREFIX,
>> +					      strlen(EXYNOS4_FIMC_LITE_PREFIX))) {
>> +					/*
>> +					 * Align width downwards, according to the FIMC-LITE
>> +					 * width step. Otherwise pipeline format negotiation
>> +					 * wouldn't succeed for widths excessing maximum sensor
>> +					 * frame width, which is probed by GStreamer, no matter
>> +					 * what actual frame size is to be set.
>> +					 */
>> +					mbus_fmt.width -= 8;
>> +				}
>> +				repeat_negotiation = 1;
>> +				break;
>> +			}
>> +
>> +			/*
>> +			 * Do not check format on FIMC.[n] source pad
>> +			 * and stop negotiation.
>> +			 */
>> +			if (!strncmp(media_entity_get_info(entity)->name,
>> +				     EXYNOS4_FIMC_PREFIX,
>> +				     strlen(EXYNOS4_FIMC_PREFIX)))
>> +				break;
>> +
>> +			pad_id = pipeline[i].src_pad->index;
>> +
>> +			/* Get format on the entity src pad */
>> +			ret = v4l2_subdev_get_format(entity, &mbus_fmt, pad_id,
>> +							V4L2_SUBDEV_FORMAT_TRY);
>> +			if (ret < 0)
>> +				return -EINVAL;
>> +
>> +			V4L2_EXYNOS4_DBG("Format propagated to the pad %s:%d: mcode: %s, cs: %s, w: %d, h: %d",
>> +					 media_entity_get_info(entity)->name, pad_id,
>> +					 v4l2_subdev_pixelcode_to_string(mbus_fmt.code),
>> +					 v4l2_subdev_colorspace_to_string(mbus_fmt.colorspace),
>> +					 mbus_fmt.width, mbus_fmt.height);
>> +
>> +			if (!strcmp(media_entity_get_info(entity)->name,
>> +				    EXYNOS4_FIMC_IS_ISP)) {
>> +				common_fmt.code = mbus_fmt.code;
>> +				common_fmt.colorspace = mbus_fmt.colorspace;
>> +				common_fmt.width -= 16;
>> +				common_fmt.height -= 12;
>> +			}
>> +
>> +			if (v4l2_subdev_format_compare(&mbus_fmt, &common_fmt)) {
>> +				repeat_negotiation = 1;
>> +				break;
>> +			}
>> +		}
>> +
>> +		if (!repeat_negotiation) {
>> +			break;
>> +		} else if (++cnt_negotiation > EXYNOS4_MAX_FMT_NEGO_NUM) {
>> +			V4L2_EXYNOS4_DBG("Pipeline format negotiation failed!");
>> +			return -EINVAL;
>> +		}
>> +	}
>> +
>> +	dev_fmt->fmt.pix_mp.width = mbus_fmt.width;
>> +	dev_fmt->fmt.pix_mp.height = mbus_fmt.height;
>> +	dev_fmt->fmt.pix_mp.field = mbus_fmt.field;
>> +	dev_fmt->fmt.pix_mp.colorspace = mbus_fmt.colorspace;
>> +
>> +	V4L2_EXYNOS4_DBG("Pipeline format successfuly negotiated");
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * @brief Apply previously negotiated pipeline format
>> + * @param plugin - this plugin.
>> + *
>> + * Apply the format, previously negotiated with negotiate_pipeline_fmt(),
>> + * on all the pipeline v4l2 sub-devices.
>> + *
>> + * @return 0 if the format was successfuly applied,
>> + * 	   or negative error code on failure.
>> + */
>> +static int apply_pipeline_fmt(struct exynos4_camera_plugin *plugin,
>> +			      struct v4l2_format *fmt)
>> +{
>> +	struct v4l2_mbus_framefmt mbus_fmt = { 0 };
>> +	struct pipeline_entity *pipeline = plugin->pipeline;
>> +	struct media_entity *entity;
>> +	struct media_pad *pad;
>> +	unsigned int i;
>> +	int ret;
>> +
>> +	if (pipeline == NULL)
>> +		return -EINVAL;
>> +
>> +	for (i = 0; i < plugin->pipeline_len - 1; i++) {
>> +		entity = pipeline[i].entity;
>> +		/*
>> +		 * Source entity is linked only through a source pad
>> +		 * and this pad should be used for setting the format.
>> +		 * For other entities set the format on a sink pad.
>> +		 */
>> +		pad = pipeline[i].sink_pad ? pipeline[i].sink_pad :
>> +					pipeline[i].src_pad;
>> +		if (pad == NULL)
>> +			return -EINVAL;
>> +
>> +		ret = v4l2_subdev_get_format(entity, &mbus_fmt, pad->index,
>> +					     V4L2_SUBDEV_FORMAT_TRY);
>> +
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		V4L2_EXYNOS4_DBG("VIDIOC_SUBDEV_G_FMT %s:%d: mcode: %s, cs: %s, w: %d, h: %d",
>> +			  media_entity_get_info(entity)->name, pad->index,
>> +			  v4l2_subdev_pixelcode_to_string(mbus_fmt.code),
>> +			  v4l2_subdev_colorspace_to_string(mbus_fmt.colorspace),
>> +			  mbus_fmt.width, mbus_fmt.height);
>> +
>> +		ret = v4l2_subdev_set_format(entity, &mbus_fmt, pad->index,
>> +					     V4L2_SUBDEV_FORMAT_ACTIVE);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		V4L2_EXYNOS4_DBG("VIDIOC_SUBDEV_S_FMT %s:%d: mcode: %s, cs: %s, w: %d, h: %d",
>> +			  media_entity_get_info(entity)->name, pad->index,
>> +			  v4l2_subdev_pixelcode_to_string(mbus_fmt.code),
>> +			  v4l2_subdev_colorspace_to_string(mbus_fmt.colorspace),
>> +			  mbus_fmt.width, mbus_fmt.height);
>> +	}
>> +
>> +	/*
>> +	 * Sink entity represents /dev/videoN node and is not
>> +	 * a sub-device. Nonetheless because it has associated
>> +	 * file descriptor and can expose v4l2-controls the
>> +	 * v4l2-subdev structure is used for caching the
>> +	 * related data.
>> +	 */
>> +	struct v4l2_subdev *sd =
>> +		media_entity_get_v4l2_subdev(pipeline[i].entity);
>> +	if (!sd)
>> +		return -EINVAL;
>> +
>> +	ret = SYS_IOCTL(sd->fd, VIDIOC_S_FMT, fmt);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * @brief Open all v4l2 sub-devices associated with pipeline entities
>> + * @param plugin - this plugin.
>> + *
>> + * Open all v4l2 sub-devices associated with the entities of the pipeline
>> + * discovered with discover_pipeline_by_entity().
>> + *
>> + * @return 0 if all v4l2 sub-devices were opened successfuly,
>> + * 	   or negative error code on failure.
>> + */
>> +static int open_pipeline(struct exynos4_camera_plugin *plugin)
>> +{
>> +	struct pipeline_entity *pipeline = plugin->pipeline;
>> +	struct media_entity *entity;
>> +	unsigned int i;
>> +	int ret;
>> +
>> +	if (pipeline == NULL)
>> +		return -EINVAL;
>> +
>> +	/*
>> +	 * Stop walking the pipeline on the last but one entity, because
>> +	 * the sink entity was already opened by libv4l2 core.
>> +	 */
>> +	for (i = 0; i < plugin->pipeline_len - 1; i++) {
>> +		entity = pipeline[i].entity;
>> +		V4L2_EXYNOS4_DBG("Opening sub-device: %s",
>> +				 media_entity_get_info(entity)->name);
>> +		ret = v4l2_subdev_open(entity);
>> +		if (ret < 0)
>> +			return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * @brief Check if there was a v4l2_ctrl binding defined for the entity
>> + * @param entity - media entity.
>> + * @param ctrl_id - v4l2 control identifier.
>> + *
>> + * Check if there was a v4l2-ctrl-binding entry defined for the entity.
>> + *
>> + * @return true if the binding exists, false otherwise.
>> + */
>> +static bool has_v4l2_ctrl_binding(struct media_entity *entity,
>> +				       int ctrl_id)
>> +{
>> +	struct v4l2_subdev *sd = media_entity_get_v4l2_subdev(entity);
>> +	int i;
>> +
>> +	if (!sd)
>> +		return false;
>> +
>> +	for (i = 0; i < sd->num_v4l2_ctrl_bindings; ++i)
>> +		if (sd->v4l2_ctrl_bindings[i] == ctrl_id)
>> +			return true;
>> +
>> +	return false;
>> +}
>> +
>> +/**
>> + * @brief Get the first pipeline entity with matching v4l2-ctrl-binding.
>> + * @param plugin - this plugin.
>> + * @param cid - v4l2-control identifier.
>> + *
>> + * Get the first pipeline entity for which v4l2-control-binding
>> + * with given cid was defined.
>> + *
>> + * @return associated entity if defined, or NULL if no matching
>> + *         v4l2-ctrl-binding was defined for any entity
>> + *         in the pipeline.
>> + */
>> +static struct media_entity *get_pipeline_entity_by_cid(
>> +				struct exynos4_camera_plugin *plugin,
>> +				int cid)
>> +{
>> +	struct pipeline_entity *pipeline = plugin->pipeline;
>> +	struct media_entity *entity;
>> +	unsigned int i;
>> +
>> +	if (pipeline == NULL)
>> +		return NULL;
>> +
>> +	for (i = 0; i < plugin->pipeline_len; i++) {
>> +		entity = pipeline[i].entity;
>> +		if (has_v4l2_ctrl_binding(entity, cid))
>> +			return entity;
>> +	}
>> +
>> +	return NULL;
>> +}
>> +
>> +/**
>> + * @brief Check if the entity is of capture type
>> + * @param entity_name - name of the entity to check
>> + *
>> + * Check if the entity name ends with a "capture", which
>> + * gives a hint that it is of capture type.
>> + *
>> + * @return True if the entity name ends with a "capture"
>> + *         string, and false otherwise.
>> + */
>> +static bool is_capture_entity(const char *entity_name)
>> +{
>> +	const char capture_segment[] = "capture";
>> +	int cap_segment_pos;
>> +
>> +	if (entity_name == NULL)
>> +		return false;
>> +
>> +	cap_segment_pos = strlen(entity_name) - strlen(capture_segment);
>> +
>> +	if (strcmp(entity_name + cap_segment_pos, capture_segment) == 0)
>> +		return true;
>> +
>> +	return false;
>> +}
>> +
>> +static __u32 convert_type(__u32 type)
>> +{
>> +	switch (type) {
>> +	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
>> +		return V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
>> +	default:
>> +		return type;
>> +	}
>> +}
>> +
>> +/* -----------------------------------------------------------------------------
>> + * Ioctl handlers
>> + */
>> +
>> +static int set_fmt_ioctl(struct exynos4_camera_plugin *plugin,
>> +				unsigned long int cmd,
>> +				struct v4l2_format *arg,
>> +				enum v4l2_subdev_format_whence set_mode)
>> +{
>> +	struct v4l2_format fmt = { 0 };
>> +	int ret;
>> +
>> +	fmt.type = convert_type(arg->type);
>> +	if (fmt.type != arg->type) {
>> +		fmt.fmt.pix_mp.width = arg->fmt.pix.width;
>> +		fmt.fmt.pix_mp.height = arg->fmt.pix.height;
>> +		fmt.fmt.pix_mp.pixelformat = arg->fmt.pix.pixelformat;
>> +		fmt.fmt.pix_mp.field = arg->fmt.pix.field;
>> +		fmt.fmt.pix_mp.colorspace = arg->fmt.pix.colorspace;
>> +		fmt.fmt.pix_mp.num_planes = 1;
>> +		fmt.fmt.pix_mp.flags = arg->fmt.pix.flags;
>> +		fmt.fmt.pix_mp.plane_fmt[0].bytesperline = arg->fmt.pix.bytesperline;
>> +		fmt.fmt.pix_mp.plane_fmt[0].sizeimage = arg->fmt.pix.sizeimage;
>> +	} else {
>> +		fmt = *arg;
>> +	}
>> +
>> +	ret = negotiate_pipeline_fmt(plugin, &fmt);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	if (set_mode == V4L2_SUBDEV_FORMAT_ACTIVE) {
>> +		ret = apply_pipeline_fmt(plugin, &fmt);
>> +		if (ret < 0)
>> +			return ret;
>> +	}
>> +
>> +	if (fmt.type != arg->type) {
>> +		arg->fmt.pix.width = fmt.fmt.pix_mp.width;
>> +		arg->fmt.pix.height = fmt.fmt.pix_mp.height;
>> +		arg->fmt.pix.pixelformat = fmt.fmt.pix_mp.pixelformat;
>> +		arg->fmt.pix.field = fmt.fmt.pix_mp.field;
>> +		arg->fmt.pix.colorspace = fmt.fmt.pix_mp.colorspace;
>> +		arg->fmt.pix.bytesperline = fmt.fmt.pix_mp.plane_fmt[0].bytesperline;
>> +		arg->fmt.pix.sizeimage = fmt.fmt.pix_mp.plane_fmt[0].sizeimage;
>> +		arg->fmt.pix.flags = fmt.fmt.pix_mp.flags;
>> +	} else {
>> +		*arg = fmt;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int get_fmt_ioctl(int fd,
>> +			 unsigned long int cmd,
>> +			 struct v4l2_format *arg)
>> +{
>> +	struct v4l2_format fmt = { 0 };
>> +	int ret;
>> +
>> +	fmt.type = convert_type(arg->type);
>> +
>> +	if (fmt.type == arg->type)
>> +		return SYS_IOCTL(fd, cmd, arg);
>> +
>> +	ret = SYS_IOCTL(fd, cmd, &fmt);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	memset(&arg->fmt.pix, 0, sizeof(arg->fmt.pix));
>> +	arg->fmt.pix.width = fmt.fmt.pix_mp.width;
>> +	arg->fmt.pix.height = fmt.fmt.pix_mp.height;
>> +	arg->fmt.pix.pixelformat = fmt.fmt.pix_mp.pixelformat;
>> +	arg->fmt.pix.field = fmt.fmt.pix_mp.field;
>> +	arg->fmt.pix.colorspace = fmt.fmt.pix_mp.colorspace;
>> +	arg->fmt.pix.bytesperline = fmt.fmt.pix_mp.plane_fmt[0].bytesperline;
>> +	arg->fmt.pix.sizeimage = fmt.fmt.pix_mp.plane_fmt[0].sizeimage;
>> +	arg->fmt.pix.flags = fmt.fmt.pix_mp.flags;
>> +
>> +	return ret;
>> +}
>> +
>> +static int buf_ioctl(int fd,
>> +		     unsigned long int cmd,
>> +		     struct v4l2_buffer *arg)
>> +{
>> +	struct v4l2_buffer buf = *arg;
>> +	struct v4l2_plane plane = { 0 };
>> +	int ret;
>> +
>> +	buf.type = convert_type(arg->type);
>> +
>> +	if (buf.type == arg->type)
>> +		return SYS_IOCTL(fd, cmd, arg);
>> +
>> +	memcpy(&plane.m, &arg->m, sizeof(plane.m));
>> +	plane.length = arg->length;
>> +	plane.bytesused = arg->bytesused;
>> +
>> +	buf.m.planes = &plane;
>> +	buf.length = 1;
>> +
>> +	ret = SYS_IOCTL(fd, cmd, &buf);
>> +
>> +	arg->index = buf.index;
>> +	arg->memory = buf.memory;
>> +	arg->flags = buf.flags;
>> +	arg->field = buf.field;
>> +	arg->timestamp = buf.timestamp;
>> +	arg->timecode = buf.timecode;
>> +	arg->sequence = buf.sequence;
>> +
>> +	arg->length = plane.length;
>> +	arg->bytesused = plane.bytesused;
>> +	memcpy(&arg->m, &plane.m, sizeof(arg->m));
>> +
>> +	return ret;
>> +}
>> +
>> +static int querycap_ioctl(int fd, struct v4l2_capability *arg)
>> +{
>> +	int ret;
>> +
>> +	ret = SYS_IOCTL(fd, VIDIOC_QUERYCAP, arg);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	arg->device_caps |= V4L2_CAP_VIDEO_CAPTURE;
>> +	arg->capabilities |= V4L2_CAP_VIDEO_CAPTURE;
>> +
>> +	return ret;
>> +}
>> +
>> +int ctrl_ioctl(struct exynos4_camera_plugin *plugin,
>> +	       unsigned long int request, struct v4l2_control *arg)
>> +{
>> +	struct pipeline_entity *pipeline = plugin->pipeline;
>> +	struct media_entity *entity;
>> +	struct v4l2_control ctrl = *arg;
>> +	struct v4l2_queryctrl queryctrl = { 0 };
>> +	bool ctrl_found = false;
>> +	int i, ret;
>> +
>> +	if (pipeline == NULL)
>> +		return -EINVAL;
>> +
>> +	/*
>> +	 * The control has to be reset to the default value
>> +	 * on all of the pipeline entities, prior setting a new
>> +	 * value. This is required in cases when the control config
>> +	 * is changed between subsequent calls to VIDIOC_S_CTRL,
>> +	 * to avoid the situation when a control is set on more
>> +	 * than one sub-device.
>> +	 */
>> +	if (request == VIDIOC_S_CTRL) {
>> +		for (i = 0; i < plugin->pipeline_len; i++) {
>> +			struct v4l2_control ctrl_def = ctrl;
>> +
>> +			entity = pipeline[i].entity;
>> +
>> +			queryctrl.id = ctrl.id;
>> +
>> +			/* query default control value */
>> +			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
>> +					VIDIOC_QUERYCTRL, &queryctrl);
>> +			if (ret < 0)
>> +				continue;
>> +
>> +			ctrl_found = true;
>> +
>> +			if (queryctrl.type & V4L2_CTRL_TYPE_BUTTON)
>> +				break;
>> +
>> +			ctrl_def.value = queryctrl.default_value;
>> +			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
>> +					VIDIOC_S_CTRL, &ctrl_def);
>> +			if (ret < 0)
>> +				return -EINVAL;
>> +		}
>> +
>> +		if (!ctrl_found) {
>> +			ret = -EINVAL;
>> +			goto exit;
>> +		}
>> +	}
>> +
>> +	entity = get_pipeline_entity_by_cid(plugin, ctrl.id);
>> +
>> +	if (entity) {
>> +		ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
>> +				request, &ctrl);
>> +	} else {
>> +		/* Walk the pipeline until the request succeeds */
>> +		ret = -ENOENT;
>> +
>> +		for (i = 0; i < plugin->pipeline_len; i++) {
>> +			entity = pipeline[i].entity;
>> +
>> +			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
>> +					request, &ctrl);
>> +			if (!ret)
>> +				break;
>> +		}
>> +	}
>> +
>> +exit:
>> +	*arg = ctrl;
>> +
>> +	V4L2_EXYNOS4_DBG("%s [id: 0x%8.8x, name: %s, entity: %s] (%d)",
>> +			 VIDIOC_CTRL(request), ctrl.id,
>> +			 ret ? NULL : queryctrl.name,
>> +			 entity ? media_entity_get_info(entity)->name :
>> +				  NULL, ret);
>> +
>> +
>> +	return ret;
>> +}
>> +
>> +static int single_ext_ctrl_ioctl(struct exynos4_camera_plugin *plugin,
>> +				 unsigned long int request,
>> +				 struct v4l2_ext_controls *arg)
>> +{
>> +	struct pipeline_entity *pipeline = plugin->pipeline;
>> +	struct media_entity *entity;
>> +	struct v4l2_ext_controls ctrls = *arg;
>> +	struct v4l2_ext_control *ctrl = &ctrls.controls[0];
>> +	struct v4l2_query_ext_ctrl queryctrl;
>> +	bool ctrl_found = 0;
>> +	int i, ret = -EINVAL;
>> +
>> +	/*
>> +	 * The control has to be reset to the default value
>> +	 * on all of the pipeline entities, prior setting a new
>> +	 * value. This is required in cases when the control config
>> +	 * is changed between subsequent calls to VIDIOC_S_EXT_CTRLS,
>> +	 * to avoid the situation when a control is set on more
>> +	 * than one sub-device.
>> +	 */
>> +	if (request == VIDIOC_S_EXT_CTRLS) {
>> +		for (i = 0; i < plugin->pipeline_len; i++) {
>> +			struct v4l2_ext_controls ctrls_def = ctrls;
>> +			struct v4l2_ext_control *ctrl_def = &ctrls_def.controls[0];
>> +
>> +			entity = pipeline[i].entity;
>> +
>> +			queryctrl.id = ctrl->id;
>> +
>> +			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
>> +					VIDIOC_QUERY_EXT_CTRL, &queryctrl);
>> +			if (ret < 0)
>> +				continue;
>> +
>> +			ctrl_found = true;
>> +
>> +			if (queryctrl.type & V4L2_CTRL_TYPE_BUTTON)
>> +				break;
>> +
>> +			ctrl_def->value64 = queryctrl.default_value;
>> +
>> +			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
>> +					VIDIOC_S_EXT_CTRLS, &ctrls_def);
>> +			if (ret < 0)
>> +				return -EINVAL;
>> +		}
>> +
>> +		if (!ctrl_found) {
>> +			ret = -EINVAL;
>> +			goto exit;
>> +		}
>> +	}
>> +
>> +	entity = get_pipeline_entity_by_cid(plugin, ctrl->id);
>> +
>> +	if (entity) {
>> +		ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
>> +				request, &ctrls);
>> +	} else {
>> +		/* Walk the pipeline until the request succeeds */
>> +		for (i = 0; i < plugin->pipeline_len; i++) {
>> +			entity = pipeline[i].entity;
>> +
>> +			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
>> +					request, &ctrls);
>> +			if (!ret)
>> +				break;
>> +		}
>> +	}
>> +
>> +exit:
>> +	*arg = ctrls;
>> +
>> +	V4L2_EXYNOS4_DBG("%s [id: 0x%8.8x, name: %s, entity: %s] (%d)",
>> +			 VIDIOC_CTRL(request), ctrl->id,
>> +			 ret ? NULL : queryctrl.name,
>> +			 entity ? media_entity_get_info(entity)->name :
>> +				  NULL, ret);
>> +
>> +	return ret;
>> +}
>> +
>> +int ext_ctrl_ioctl(struct exynos4_camera_plugin *plugin,
>> +		   unsigned long int request,
>> +		   struct v4l2_ext_controls *arg)
>> +{
>> +	struct v4l2_ext_controls out_ctrls = *arg, ctrls = *arg;
>> +	int ret = -EINVAL, i;
>> +
>> +	ctrls.count = 1;
>> +
>> +	/*
>> +	 * Split cluster to individual ioctl calls for each control
>> +	 * from the array, to make possible redirection of every
>> +	 * single control to different sub-device, according to the
>> +	 * configuration settings.
>> +	 */
>> +	for (i = 0; i < arg->count; ++i) {
>> +		ctrls.controls = &arg->controls[i];
>> +
>> +		ret = single_ext_ctrl_ioctl(plugin, request, &ctrls);
>> +		out_ctrls.controls[i] = ctrls.controls[i];
>> +		if (ret < 0) {
>> +			if (ctrls.error_idx == 1)
>> +				out_ctrls.error_idx = ctrls.count;
>> +			else
>> +				out_ctrls.error_idx = i;
>> +			break;
>> +		}
>> +	}
>> +
>> +	*arg = out_ctrls;
>> +	return ret;
>> +}
>> +
>> +int sort_ctrls(const void * a, const void * b)
>> +{
>> +	const struct media_entity_to_cid *ctrl_a = a, *ctrl_b = b;
>> +
>> +	return ctrl_a->queryctrl.id - ctrl_b->queryctrl.id;
>> +}
>> +
>> +int queryctrl_ioctl(struct exynos4_camera_plugin *plugin,
>> +		    struct v4l2_queryctrl *arg)
>> +{
>> +	struct pipeline_entity *pipeline = plugin->pipeline;
>> +	struct media_entity *entity, *target_entity;
>> +	struct v4l2_queryctrl queryctrl = *arg;
>> +	struct media_entity_to_cid *ctrls_found;
>> +	int i, ret = -EINVAL, num_ctrls = 0;
>> +
>> +	/*
>> +	 * If id is or'ed with V4L2_CTRL_FLAG_NEXT_CTRL then the control to
>> +	 * be found is the one with the next lowest id among all entities
>> +	 * in the pipeline.
>> +	 */
>> +	if (queryctrl.id & V4L2_CTRL_FLAG_NEXT_CTRL) {
>> +		ctrls_found = malloc(sizeof(*ctrls_found));
>> +
>> +		for (i = 0; i < plugin->pipeline_len; i++) {
>> +			entity = pipeline[i].entity;
>> +
>> +			queryctrl = *arg;
>> +
>> +			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
>> +					VIDIOC_QUERYCTRL, &queryctrl);
>> +			if (!ret) {
>> +				ctrls_found = realloc(ctrls_found,
>> +					sizeof(*ctrls_found) * (num_ctrls + 1));
>> +				ctrls_found[num_ctrls].queryctrl = queryctrl;
>> +				ctrls_found[num_ctrls].entity = entity;
>> +				++num_ctrls;
>> +			}
>> +		}
>> +
>> +		if (num_ctrls == 0) {
>> +			ret = -EINVAL;
>> +			entity = NULL;
>> +			goto done;
>> +		}
>> +
>> +		qsort(ctrls_found, num_ctrls, sizeof(*ctrls_found), sort_ctrls);
>> +
>> +		queryctrl = ctrls_found[0].queryctrl;
>> +		target_entity = ctrls_found[0].entity;
>> +
>> +		free(ctrls_found);
>> +	}
>> +
>> +	entity = get_pipeline_entity_by_cid(plugin, queryctrl.id);
>> +	if (entity)
>> +		target_entity = entity;
>> +
>> +	ret = SYS_IOCTL(media_entity_get_v4l2_subdev(target_entity)->fd,
>> +			VIDIOC_QUERYCTRL, &queryctrl);
>> +
>> +done:
>> +	V4L2_EXYNOS4_DBG(
>> +		"VIDIOC_QUERYCTRL [id: 0x%8.8x, name: %s, entity: %s] (%d)",
>> +		ret ? arg->id : queryctrl.id, ret ? NULL : queryctrl.name,
>> +		target_entity ? media_entity_get_info(target_entity)->name :
>> +				NULL, ret);
>> +
>> +	*arg = queryctrl;
>> +
>> +	return ret;
>> +}
>> +
>> +int query_ext_ctrl_ioctl(struct exynos4_camera_plugin *plugin,
>> +			 struct v4l2_query_ext_ctrl *arg)
>> +{
>> +	struct pipeline_entity *pipeline = plugin->pipeline;
>> +	struct media_entity *entity, *target_entity;
>> +	struct v4l2_query_ext_ctrl query_ext_ctrl = *arg;
>> +	struct media_entity_to_cid *ctrls_found;
>> +	int i, ret = -EINVAL, num_ctrls = 0;
>> +
>> +	/*
>> +	 * If id is or'ed with V4L2_CTRL_FLAG_NEXT_CTRL then the control to
>> +	 * be found is the one with the next lowest id among all entities
>> +	 * in the pipeline.
>> +	 */
>> +	if (query_ext_ctrl.id & V4L2_CTRL_FLAG_NEXT_CTRL) {
>> +		ctrls_found = malloc(sizeof(*ctrls_found));
>> +
>> +		for (i = 0; i < plugin->pipeline_len; i++) {
>> +			entity = pipeline[i].entity;
>> +
>> +			query_ext_ctrl = *arg;
>> +
>> +			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
>> +					VIDIOC_QUERY_EXT_CTRL, &query_ext_ctrl.id);
>> +			if (!ret) {
>> +				ctrls_found = realloc(ctrls_found,
>> +					sizeof(*ctrls_found) * (num_ctrls + 1));
>> +				ctrls_found[num_ctrls].query_ext_ctrl =
>> +								query_ext_ctrl;
>> +				ctrls_found[num_ctrls].entity = entity;
>> +				++num_ctrls;
>> +			}
>> +		}
>> +
>> +		if (num_ctrls == 0) {
>> +			ret = -EINVAL;
>> +			entity = NULL;
>> +			goto done;
>> +		}
>> +
>> +		qsort(ctrls_found, num_ctrls, sizeof(*ctrls_found), sort_ctrls);
>> +
>> +		query_ext_ctrl = ctrls_found[0].query_ext_ctrl;
>> +		target_entity = ctrls_found[0].entity;
>> +
>> +		free(ctrls_found);
>> +	}
>> +
>> +	entity = get_pipeline_entity_by_cid(plugin, query_ext_ctrl.id);
>> +	if (entity)
>> +		target_entity = entity;
>> +
>> +	ret = SYS_IOCTL(media_entity_get_v4l2_subdev(target_entity)->fd,
>> +			VIDIOC_QUERYCTRL, &query_ext_ctrl);
>> +
>> +done:
>> +	V4L2_EXYNOS4_DBG(
>> +		"VIDIOC_QUERY_EXT_CTRL [id: 0x%8.8x, name: %s, entity: %s] (%d)",
>> +		ret ? arg->id : query_ext_ctrl.id,
>> +		ret ? NULL : query_ext_ctrl.name,
>> +		target_entity ? media_entity_get_info(target_entity)->name :
>> +				NULL, ret);
>> +
>> +	*arg = query_ext_ctrl;
>> +
>> +	return ret;
>> +}
>> +
>> +int querymenu_ioctl(struct exynos4_camera_plugin *plugin,
>> +		    struct v4l2_querymenu *arg)
>
> static? I presume a lot of the other functions should be static as well.

Ah right, I missed these ones.

>> +{
>> +	struct pipeline_entity *pipeline = plugin->pipeline;
>> +	struct media_entity *entity;
>> +	struct v4l2_querymenu querymenu = *arg;
>> +	int i, ret = -EINVAL;
>> +
>> +	entity = get_pipeline_entity_by_cid(plugin, querymenu.id);
>> +	if (entity) {
>> +		ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
>> +			        VIDIOC_QUERYMENU, &querymenu);
>> +		goto exit;
>> +	}
>> +
>> +	for (i = 0; i < plugin->pipeline_len; i++) {
>> +		entity = pipeline[i].entity;
>> +
>> +		ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
>> +				VIDIOC_QUERYMENU, &querymenu);
>> +		if (!ret)
>> +			break;
>> +	}
>> +
>> +exit:
>> +	*arg = querymenu;
>> +
>> +	V4L2_EXYNOS4_DBG(
>> +		"VIDIOC_QUERYMENU [id: 0x%8.8x, name: %s, entity: %s] (%d)",
>> +		querymenu.id, ret ? NULL : querymenu.name,
>> +		entity ? media_entity_get_info(entity)->name : NULL, ret);
>> +
>> +	return ret;
>> +}
>> +
>> +static void *plugin_init(int fd)
>> +{
>> +	struct v4l2_capability cap = { 0 };
>> +	struct exynos4_camera_plugin *plugin = NULL;
>> +	const char *sink_entity_name;
>> +	struct media_device *media;
>> +	struct media_entity *sink_entity;
>> +	int ret;
>> +
>> +	ret = SYS_IOCTL(fd, VIDIOC_QUERYCAP, &cap);
>> +	if (ret < 0) {
>> +		V4L2_EXYNOS4_ERR("Failed to query video capabilities.");
>> +		return NULL;
>> +	}
>> +
>> +	/* Check if this is Exynos4 media device */
>> +	if (strcmp((char *) cap.driver, EXYNOS4_FIMC_DRV) &&
>> +	    strcmp((char *) cap.driver, EXYNOS4_FIMC_LITE_DRV) &&
>> +	    strcmp((char *) cap.driver, EXYNOS4_FIMC_IS_ISP_DRV)) {
>> +		V4L2_EXYNOS4_ERR("Not an Exynos4 media device.");
>> +		return NULL;
>> +	}
>> +
>> +	/*
>> +	 * Create a representation of the media device
>> +	 * containing the opened video device.
>> +	 */
>> +	media = media_device_new_by_subdev_fd(fd, &sink_entity);
>> +	if (media == NULL) {
>> +		V4L2_EXYNOS4_ERR("Failed to create media device.");
>> +		return NULL;
>> +	}
>> +
>> +#ifdef DEBUG
>> +	media_debug_set_handler(media, (void (*)(void *, ...))fprintf, stdout);
>> +#endif
>> +
>> +	sink_entity_name = media_entity_get_info(sink_entity)->name;
>> +
>> +	/* Check if video entity is of capture type, not m2m */
>> +	if (!is_capture_entity(sink_entity_name)) {
>> +		V4L2_EXYNOS4_ERR("Device not of capture type.");
>> +		goto err_get_sink_entity;
>> +	}
>> +
>> +	/*
>> +	 * Initialize sink_entity subdev fd with the one opened
>> +	 * by the libv4l core to avoid losing it on pipeline opening.
>> +	 */
>> +	v4l2_subdev_create_opened(sink_entity, fd);
>> +
>> +	/* Parse media configuration file and apply its settings */
>> +	ret = mediatext_parse_setup_config(media, EXYNOS4_CAPTURE_CONF);
>> +	if (ret < 0) {
>> +		V4L2_EXYNOS4_ERR("Media config parser error.");
>> +		goto err_get_sink_entity;
>> +	}
>> +
>> +	/* Allocate private data */
>> +	plugin = calloc(1, sizeof(*plugin));
>> +	if (!plugin)
>> +		goto err_get_sink_entity;
>> +
>> +	plugin->media = media;
>> +
>> +	/*
>> +	 * Discover the pipeline of sub-devices from a camera sensor
>> +	 * to the opened video device.
>> +	 */
>> +	ret = discover_pipeline_by_entity(plugin, sink_entity);
>> +	if (ret < 0) {
>> +		V4L2_EXYNOS4_ERR("Error discovering video pipeline.");
>> +		goto err_discover_pipeline;
>> +	}
>> +
>> +	/* Open all sub-devices in the discovered pipeline */
>> +	ret = open_pipeline(plugin);
>> +	if (ret < 0) {
>> +		V4L2_EXYNOS4_ERR("Error opening video pipeline.");
>> +		goto err_discover_pipeline;
>> +	}
>> +
>> +	V4L2_EXYNOS4_LOG("Initialized exynos4-camera plugin.");
>> +
>> +	return plugin;
>> +
>> +err_discover_pipeline:
>> +	free(plugin);
>> +err_get_sink_entity:
>> +	if (media)
>> +		media_device_unref(media);
>> +	return NULL;
>> +}
>> +
>> +static void plugin_close(void *dev_ops_priv)
>> +{
>> +	struct exynos4_camera_plugin *plugin = dev_ops_priv;
>> +
>> +	if (plugin == NULL)
>> +		return;
>> +
>> +	media_device_unref(plugin->media);
>> +
>> +	free(plugin);
>> +}
>> +
>> +static int plugin_ioctl(void *dev_ops_priv, int fd, unsigned long int cmd,
>> +			void *arg)
>> +{
>> +	struct exynos4_camera_plugin *plugin = dev_ops_priv;
>> +
>> +	if (plugin == NULL || arg == NULL)
>> +		return -EINVAL;
>> +
>> +	switch (cmd) {
>> +	case VIDIOC_S_CTRL:
>> +	case VIDIOC_G_CTRL:
>> +		return ctrl_ioctl(plugin, cmd, arg);
>> +	case VIDIOC_S_EXT_CTRLS:
>> +	case VIDIOC_G_EXT_CTRLS:
>> +	case VIDIOC_TRY_EXT_CTRLS:
>> +		return ext_ctrl_ioctl(plugin, cmd, arg);
>> +	case VIDIOC_QUERYCTRL:
>> +		return queryctrl_ioctl(plugin, arg);
>> +	case VIDIOC_QUERY_EXT_CTRL:
>> +		return query_ext_ctrl_ioctl(plugin, arg);
>> +	case VIDIOC_QUERYMENU:
>> +		return querymenu_ioctl(plugin, arg);
>> +	case VIDIOC_TRY_FMT:
>> +		return set_fmt_ioctl(plugin, cmd, arg,
>> +				     V4L2_SUBDEV_FORMAT_TRY);
>> +	case VIDIOC_S_FMT:
>> +		return set_fmt_ioctl(plugin, cmd, arg,
>> +				     V4L2_SUBDEV_FORMAT_ACTIVE);
>> +	case VIDIOC_G_FMT:
>> +		return get_fmt_ioctl(fd, cmd, arg);
>> +	case VIDIOC_QUERYCAP:
>> +		return querycap_ioctl(fd, arg);
>> +	case VIDIOC_QBUF:
>> +	case VIDIOC_DQBUF:
>> +	case VIDIOC_QUERYBUF:
>> +	case VIDIOC_PREPARE_BUF:
>> +		return buf_ioctl(fd, cmd, arg);
>> +	case VIDIOC_REQBUFS:
>> +		return SIMPLE_CONVERT_IOCTL(fd, cmd, arg,
>> +					    v4l2_requestbuffers);
>> +	case VIDIOC_ENUM_FMT:
>> +		return SIMPLE_CONVERT_IOCTL(fd, cmd, arg, v4l2_fmtdesc);
>> +	case VIDIOC_CROPCAP:
>> +		return SIMPLE_CONVERT_IOCTL(fd, cmd, arg, v4l2_cropcap);
>> +	case VIDIOC_STREAMON:
>> +	case VIDIOC_STREAMOFF:
>> +		{
>> +			int *arg_type = (int *) arg;
>> +			__u32 type;
>> +
>> +			type = convert_type(*arg_type);
>> +
>> +			if (type != V4L2_BUF_TYPE_VIDEO_CAPTURE &&
>> +			    type != V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE) {
>> +				V4L2_EXYNOS4_ERR("Invalid buffer type.");
>> +				return -EINVAL;
>> +			}
>> +
>> +			return SYS_IOCTL(fd, cmd, &type);
>> +		}
>> +
>> +	default:
>> +		return SYS_IOCTL(fd, cmd, arg);
>> +	}
>> +}
>> +
>> +PLUGIN_PUBLIC const struct libv4l_dev_ops libv4l2_plugin = {
>> +	.init = &plugin_init,
>> +	.close = &plugin_close,
>> +	.ioctl = &plugin_ioctl,
>> +};
>

Sakari Ailus Nov. 24, 2016, 11:55 p.m. UTC | #3

Hi Jacek,

On Thu, Nov 24, 2016 at 05:14:40PM +0100, Jacek Anaszewski wrote:
> Hi Sakari,
> 
> On 11/24/2016 04:11 PM, Sakari Ailus wrote:
> >Hi Jacek,
> >
> >Thank you for your continued work on the Exynos plugin patchset!
> >
> >I think we're pretty close to being able to merge the set, if you could
> >still bear with me awhile. :-)
> 
> Your demanding reviewer I must admit. :-)
> Of course, I appreciate all your remarks, they're highly valuable.
> 
> >On Wed, Oct 12, 2016 at 04:35:22PM +0200, Jacek Anaszewski wrote:
> >...
> >>diff --git a/lib/libv4l-exynos4-camera/Makefile.am b/lib/libv4l-exynos4-camera/Makefile.am
> >>new file mode 100644
> >>index 0000000..c38b7f6
> >>--- /dev/null
> >>+++ b/lib/libv4l-exynos4-camera/Makefile.am
> >>@@ -0,0 +1,19 @@
> >>+if WITH_V4L_PLUGINS
> >>+libv4l2plugin_LTLIBRARIES = libv4l-exynos4-camera.la
> >>+endif
> >>+
> >>+media-bus-format-names.h: ../../include/linux/media-bus-format.h
> >>+	sed -e '/#define MEDIA_BUS_FMT/ ! d; s/.*FMT_//; /FIXED/ d; s/\t.*//; s/.*/{ \"&\", MEDIA_BUS_FMT_& },/;' \
> >>+	< $< > $@
> >>+
> >>+media-bus-format-codes.h: ../../include/linux/media-bus-format.h
> >>+	sed -e '/#define MEDIA_BUS_FMT/ ! d; s/.*#define //; /FIXED/ d; s/\t.*//; s/.*/ &,/;' \
> >>+	< $< > $@
> >>+
> >>+BUILT_SOURCES = media-bus-format-names.h media-bus-format-codes.h
> >>+CLEANFILES = $(BUILT_SOURCES)
> >
> >It'd be nice to be able to use the same generated headers that now are under
> >utils/media-ctl, instead of copying the sed script here in verbatim. If the
> >script is changed or fixed in some way, the other location probably will
> >remain unchanged...
> 
> The problem is that those headers are built after this plugin.

They could be moved to another directory from where they are now, and
explicitly built as a dependency. I don't know how to properly do that with
automake though.

I cc'd Gregor to the thread.

> 
> >I wonder if there's a proper way to generate build time headers such as
> >these.
> >
> >Another less good alternative would be to put these into a separate Makefile
> >and include that Makefile where the headers are needed. But I don't like
> >that much either, it's a hack.
> 
> In this case it seems to be the only feasible optimization.

I'm ok with that but still hope we could have something better. :-)

> 
> >>+
> >>+nodist_libv4l_exynos4_camera_la_SOURCES = $(BUILT_SOURCES)
> >>+libv4l_exynos4_camera_la_SOURCES = libv4l-exynos4-camera.c ../../utils/media-ctl/libmediactl.c ../../utils/media-ctl/libv4l2subdev.c ../../utils/media-ctl/mediatext.c
> >>+libv4l_exynos4_camera_la_CFLAGS = -fvisibility=hidden -std=gnu99
> >>+libv4l_exynos4_camera_la_LDFLAGS = -avoid-version -module -shared -export-dynamic -lpthread
> >>diff --git a/lib/libv4l-exynos4-camera/libv4l-exynos4-camera.c b/lib/libv4l-exynos4-camera/libv4l-exynos4-camera.c
> >>new file mode 100644
> >>index 0000000..c219fe5
> >>--- /dev/null
> >>+++ b/lib/libv4l-exynos4-camera/libv4l-exynos4-camera.c
> >>@@ -0,0 +1,1325 @@
> >>+/*
> >>+ * Copyright (c) 2016 Samsung Electronics Co., Ltd.
> >>+ *              http://www.samsung.com
> >>+ *
> >>+ * Author: Jacek Anaszewski <[e-mail]>
> >>+ *
> >>+ * This program is free software; you can redistribute it and/or modify
> >>+ * it under the terms of the GNU Lesser General Public License as published by
> >>+ * the Free Software Foundation; either version 2.1 of the License, or
> >>+ * (at your option) any later version.
> >>+ *
> >>+ * This program is distributed in the hope that it will be useful,
> >>+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
> >>+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> >>+ * Lesser General Public License for more details.
> >>+ */
> >>+
> >>+#include <config.h>
> >>+#include <errno.h>
> >>+#include <linux/types.h>
> >>+#include <stdbool.h>
> >>+#include <stdint.h>
> >>+#include <stdio.h>
> >>+#include <stdlib.h>
> >>+#include <string.h>
> >>+#include <sys/ioctl.h>
> >>+#include <sys/syscall.h>
> >>+#include <unistd.h>
> >>+
> >>+#include "../../utils/media-ctl/mediactl.h"
> >>+#include "../../utils/media-ctl/mediatext.h"
> >>+#include "../../utils/media-ctl/v4l2subdev.h"
> >>+#include "libv4l-plugin.h"
> >>+
> >>+#ifdef DEBUG
> >>+#define V4L2_EXYNOS4_DBG(format, ARG...)\
> >>+	printf("[%s:%d] [%s] " format " \n", __FILE__, __LINE__, __func__, ##ARG)
> >>+#else
> >>+#define V4L2_EXYNOS4_DBG(format, ARG...)
> >>+#endif
> >>+
> >>+#define V4L2_EXYNOS4_ERR(format, ARG...)\
> >>+	fprintf(stderr, "Libv4l Exynos4 camera plugin: "format "\n", ##ARG)
> >>+
> >>+#define V4L2_EXYNOS4_LOG(format, ARG...)\
> >>+	fprintf(stdout, "Libv4l Exynos4 camera plugin: "format "\n", ##ARG)
> >>+
> >>+#define VIDIOC_CTRL(type)				\
> >>+	((type) == VIDIOC_S_CTRL ? "VIDIOC_S_CTRL" :	\
> >>+				   "VIDIOC_G_CTRL")
> >>+
> >>+#if HAVE_VISIBILITY
> >>+#define PLUGIN_PUBLIC __attribute__ ((visibility("default")))
> >>+#else
> >>+#define PLUGIN_PUBLIC
> >>+#endif
> >>+
> >>+#define SYS_IOCTL(fd, cmd, arg) \
> >>+	syscall(SYS_ioctl, (int)(fd), (unsigned long)(cmd), (void *)(arg))
> >>+
> >>+#define SIMPLE_CONVERT_IOCTL(fd, cmd, arg, __struc) ({  \
> >>+	int __ret;                                      \
> >>+	struct __struc *req = arg;                      \
> >>+	uint32_t type = req->type;                      \
> >>+	req->type = convert_type(type);                 \
> >>+	__ret = SYS_IOCTL(fd, cmd, arg);                \
> >>+	req->type = type;                               \
> >>+	__ret;                                          \
> >>+	})
> >>+
> >>+#ifndef min
> >>+#define min(a, b) (((a) < (b)) ? (a) : (b))
> >>+#endif
> >>+
> >>+#ifndef max
> >>+#define max(a, b) (((a) > (b)) ? (a) : (b))
> >>+#endif
> >>+
> >>+#define EXYNOS4_FIMC_DRV	"exynos4-fimc"
> >>+#define EXYNOS4_FIMC_LITE_DRV	"exynos-fimc-lit"
> >>+#define EXYNOS4_FIMC_IS_ISP_DRV	"exynos4-fimc-is"
> >>+#define EXYNOS4_CAPTURE_CONF	"/var/lib/libv4l/exynos4_capture_conf"
> >
> >Is this something that should be configurable in ./configure?
> 
> OK.
> 
> >
> >>+#define EXYNOS4_FIMC_IS_ISP	"FIMC-IS-ISP"
> >>+#define EXYNOS4_S5K6A3		"S5K6A3"
> >
> >Maybe this one as well. But it could come from a configuration file, too.
> 
> Right, the sensor is independent of SoC.
> 
> >
> >The problem at large is actually something else: how do you recognise the
> >hardware you're running on?
> >
> >You could find the sensor by walking the media graph.
> >
> >But if you need to know something very hardware specific it might not be
> >available through the generic interfaces, and you might need to know the
> >exact hardware you have.
> >
> >How do you know that you should load a particular plugin? I wonder if we
> >could add a small snippet of code to detect different kinds of systems, I
> >presume this is the plugin you want to load if the user has opened a video
> >node of the Exynos4 ISP; you could find through the Media controller.
> 
> This code snippet in plugin_init() detects if we are on Exynos4 media
> device:
> 
>         ret = SYS_IOCTL(fd, VIDIOC_QUERYCAP, &cap);
>         if (ret < 0) {
>                 V4L2_EXYNOS4_ERR("Failed to query video capabilities.");
>                 return NULL;
>         }
> 
>         /* Check if this is Exynos4 media device */
>         if (strcmp((char *) cap.driver, EXYNOS4_FIMC_DRV) &&
>             strcmp((char *) cap.driver, EXYNOS4_FIMC_LITE_DRV) &&
>             strcmp((char *) cap.driver, EXYNOS4_FIMC_IS_ISP_DRV)) {
>                 V4L2_EXYNOS4_ERR("Not an Exynos4 media device.");
>                 return NULL;
>         }
> 
> Additionally I check if this is capture and not m2m device:
> 
>         /* Check if video entity is of capture type, not m2m */
>         if (!is_capture_entity(sink_entity_name)) {
>                 V4L2_EXYNOS4_ERR("Device not of capture type.");
>                 goto err_get_sink_entity;
>         }

Ah, indeed. I presume it should work just fine then. Good.

The approach doesn't look too scalable still, but I don't think there's
a reason to worry about that now.

> 
> 
> 
> >
> >That's certainly out of scope of the patchset, I just thought of binging up
> >the topics for discussion. :-)
> >
> >>+#define EXYNOS4_FIMC_LITE_PREFIX "FIMC-LITE."
> >>+#define EXYNOS4_FIMC_PREFIX	"FIMC."
> >>+#define EXYNOS4_MAX_FMT_NEGO_NUM 50
> >>+#define EXYNOS4_MAX_PIPELINE_LEN 7
> >>+
> >>+struct media_device;
> >>+struct media_entity;
> >>+
> >>+/*
> >>+ * struct pipeline_entity - linked media device pipeline
> >>+ * @entity:		linked entity
> >>+ * @sink_pad:		inbound link pad of the entity
> >>+ * @src_pad:		outbound link pad of the entity
> >>+ */
> >>+struct pipeline_entity {
> >>+	struct media_entity *entity;
> >>+	struct media_pad *sink_pad;
> >>+	struct media_pad *src_pad;
> >>+};
> >>+
> >>+/*
> >>+ * struct media_entity_to_cid - entity to control map
> >>+ * @entity:		media entity
> >>+ * @sink_pad:		inbound link pad of the entity
> >>+ * @src_pad:		outbound link pad of the entity
> >>+ */
> >>+struct media_entity_to_cid {
> >>+	struct media_entity *entity;
> >>+	union {
> >>+		struct v4l2_queryctrl queryctrl;
> >>+		struct v4l2_query_ext_ctrl query_ext_ctrl;
> >>+	};
> >>+};
> >>+
> >>+/*
> >>+ * struct exynos4_camera_plugin - libv4l exynos4 camera plugin
> >>+ * @media:		media device comprising the opened video device
> >>+ * @pipeline:		video pipeline, element 0 is the source entity
> >>+ * @pipeline_len:	length of the video pipeline
> >>+ */
> >>+struct exynos4_camera_plugin {
> >
> >static?
> 
> Right.
> 
> >>+	struct media_device *media;
> >>+	struct pipeline_entity pipeline[EXYNOS4_MAX_PIPELINE_LEN];
> >>+	unsigned int pipeline_len;
> >>+};
> >>+
> >>+/* -----------------------------------------------------------------------------
> >>+ * Pipeline operations
> >>+ */
> >>+
> >>+/**
> >>+ * @brief Discover video pipeline for given sink entity
> >>+ * @param plugin - this plugin.
> >>+ * @param entity - sink entity of the pipeline.
> >>+ *
> >>+ * Discover the video pipeline, by walking starting from the
> >>+ * sink entity upwards until a source entity is encountered.
> >>+ *
> >>+ * @return 0 if the sensor entity was detected,
> >>+ * 	   or negative error code on failure.
> >>+ */
> >>+static int discover_pipeline_by_entity(struct exynos4_camera_plugin *plugin,
> >>+				       struct media_entity *entity)
> >>+{
> >>+	struct pipeline_entity reverse_pipeline[EXYNOS4_MAX_PIPELINE_LEN];
> >>+	struct media_pad *src_pad;
> >>+	struct media_link *link = NULL, *backlinks[2];
> >>+	unsigned int num_backlinks, cur_pipe_pos = 0;
> >>+	int i, j;
> >>+	int ret;
> >>+
> >>+	if (entity == NULL)
> >>+		return -EINVAL;
> >>+
> >>+	for (;;) {
> >>+		/* Cache the recently discovered entity. */
> >>+		reverse_pipeline[cur_pipe_pos].entity = entity;
> >>+
> >>+		/* Cache the source pad used for linking the entity. */
> >>+		if (link)
> >>+			reverse_pipeline[cur_pipe_pos].src_pad = link->source;
> >>+
> >>+		ret = media_entity_get_backlinks(entity, backlinks,
> >>+						 &num_backlinks);
> >>+		if (ret < 0)
> >>+			return ret;
> >>+
> >>+		/* Check if pipeline source entity has been reached. */
> >>+		if (num_backlinks > 2) {
> >>+			V4L2_EXYNOS4_DBG("Unexpected number of busy sink pads (%d)",
> >>+					 num_backlinks);
> >>+			return -EINVAL;
> >>+		} else if (num_backlinks == 2) {
> >>+			/*
> >>+			 * Allow two active pads only in case of
> >>+			 * S5C73M3-OIF entity.
> >>+			 */
> >>+			if (strcmp(media_entity_get_info(entity)->name,
> >>+				   "S5C73M3-OIF")) {
> >>+				V4L2_EXYNOS4_DBG("Ambiguous media device topology: "
> >>+						 "two busy sink pads");
> >>+				return -EINVAL;
> >>+			}
> >>+			/*
> >>+			 * Two active links are allowed betwen S5C73M3-OIF and
> >>+			 * S5C73M3 entities. In such a case route through the
> >>+			 * pad with id == 0 has to be chosen.
> >>+			 */
> >>+			link = NULL;
> >>+			for (i = 0; i < num_backlinks; i++)
> >>+				if (backlinks[i]->sink->index == 0)
> >>+					link = backlinks[i];
> >>+			if (link == NULL)
> >>+				return -EINVAL;
> >>+		} else if (num_backlinks == 1) {
> >>+			link = backlinks[0];
> >>+		} else {
> >>+			reverse_pipeline[cur_pipe_pos].sink_pad = NULL;
> >>+			break;
> >>+		}
> >>+
> >>+		/* Cache the sink pad used for linking the entity. */
> >>+		reverse_pipeline[cur_pipe_pos].sink_pad = link->sink;
> >>+
> >>+		V4L2_EXYNOS4_DBG("Discovered sink pad %d for the %s entity",
> >>+				 reverse_pipeline[cur_pipe_pos].sink_pad->index,
> >>+				 media_entity_get_info(entity)->name);
> >>+
> >>+		src_pad = media_entity_remote_source(link->sink);
> >>+		if (!src_pad)
> >>+			return -EINVAL;
> >>+
> >>+		entity = src_pad->entity;
> >>+		if (++cur_pipe_pos == EXYNOS4_MAX_PIPELINE_LEN)
> >>+			return -EINVAL;
> >>+	}
> >>+
> >>+	/*
> >>+	 * Reorder discovered pipeline elements so that the sensor
> >>+	 * entity was the pipeline head.
> >>+	 */
> >>+	j = 0;
> >>+	for (i = cur_pipe_pos; i >= 0; i--)
> >
> >How about:
> >
> >	for (i = cur_pipe_pos, j = 0; i >= 0; i--, j++)
> >
> >And you can avoid setting j to zero outside the loop plus incrementing j++
> >where it doesn't seem to fit too well.
> 
> I was thinking about it, but finally decided that this arrangement
> will improve readability. Nothing prevents us to apply the
> optimizations you've just suggested though.

You could do that using a single loop variable, replacing j by cur_pipe_pos
- i. Up to you. :-)

> 
> >>+		plugin->pipeline[j++] = reverse_pipeline[i];
> >>+
> >>+	plugin->pipeline_len = j;
> >>+
> >>+	return 0;
> >>+}
> >>+

Patch

diff --git a/configure.ac b/configure.ac
index 8447f05..692718a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -17,6 +17,7 @@  AC_CONFIG_FILES([Makefile
 	lib/libdvbv5/Makefile
 	lib/libv4l2rds/Makefile
 	lib/libv4l-mplane/Makefile
+	lib/libv4l-exynos4-camera/Makefile
 
 	utils/Makefile
 	utils/libv4l2util/Makefile
diff --git a/lib/Makefile.am b/lib/Makefile.am
index a105c95..b5e52db 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -5,6 +5,11 @@  SUBDIRS = \
 	libv4l2rds \
 	libv4l-mplane
 
+if WITH_V4LUTILS
+SUBDIRS += \
+	libv4l-exynos4-camera
+endif
+
 if WITH_LIBDVBV5
 SUBDIRS += \
 	libdvbv5
diff --git a/lib/libv4l-exynos4-camera/Makefile.am b/lib/libv4l-exynos4-camera/Makefile.am
new file mode 100644
index 0000000..c38b7f6
--- /dev/null
+++ b/lib/libv4l-exynos4-camera/Makefile.am
@@ -0,0 +1,19 @@ 
+if WITH_V4L_PLUGINS
+libv4l2plugin_LTLIBRARIES = libv4l-exynos4-camera.la
+endif
+
+media-bus-format-names.h: ../../include/linux/media-bus-format.h
+	sed -e '/#define MEDIA_BUS_FMT/ ! d; s/.*FMT_//; /FIXED/ d; s/\t.*//; s/.*/{ \"&\", MEDIA_BUS_FMT_& },/;' \
+	< $< > $@
+
+media-bus-format-codes.h: ../../include/linux/media-bus-format.h
+	sed -e '/#define MEDIA_BUS_FMT/ ! d; s/.*#define //; /FIXED/ d; s/\t.*//; s/.*/ &,/;' \
+	< $< > $@
+
+BUILT_SOURCES = media-bus-format-names.h media-bus-format-codes.h
+CLEANFILES = $(BUILT_SOURCES)
+
+nodist_libv4l_exynos4_camera_la_SOURCES = $(BUILT_SOURCES)
+libv4l_exynos4_camera_la_SOURCES = libv4l-exynos4-camera.c ../../utils/media-ctl/libmediactl.c ../../utils/media-ctl/libv4l2subdev.c ../../utils/media-ctl/mediatext.c
+libv4l_exynos4_camera_la_CFLAGS = -fvisibility=hidden -std=gnu99
+libv4l_exynos4_camera_la_LDFLAGS = -avoid-version -module -shared -export-dynamic -lpthread
diff --git a/lib/libv4l-exynos4-camera/libv4l-exynos4-camera.c b/lib/libv4l-exynos4-camera/libv4l-exynos4-camera.c
new file mode 100644
index 0000000..c219fe5
--- /dev/null
+++ b/lib/libv4l-exynos4-camera/libv4l-exynos4-camera.c
@@ -0,0 +1,1325 @@ 
+/*
+ * Copyright (c) 2016 Samsung Electronics Co., Ltd.
+ *              http://www.samsung.com
+ *
+ * Author: Jacek Anaszewski <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ */
+
+#include <config.h>
+#include <errno.h>
+#include <linux/types.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#include "../../utils/media-ctl/mediactl.h"
+#include "../../utils/media-ctl/mediatext.h"
+#include "../../utils/media-ctl/v4l2subdev.h"
+#include "libv4l-plugin.h"
+
+#ifdef DEBUG
+#define V4L2_EXYNOS4_DBG(format, ARG...)\
+	printf("[%s:%d] [%s] " format " \n", __FILE__, __LINE__, __func__, ##ARG)
+#else
+#define V4L2_EXYNOS4_DBG(format, ARG...)
+#endif
+
+#define V4L2_EXYNOS4_ERR(format, ARG...)\
+	fprintf(stderr, "Libv4l Exynos4 camera plugin: "format "\n", ##ARG)
+
+#define V4L2_EXYNOS4_LOG(format, ARG...)\
+	fprintf(stdout, "Libv4l Exynos4 camera plugin: "format "\n", ##ARG)
+
+#define VIDIOC_CTRL(type)				\
+	((type) == VIDIOC_S_CTRL ? "VIDIOC_S_CTRL" :	\
+				   "VIDIOC_G_CTRL")
+
+#if HAVE_VISIBILITY
+#define PLUGIN_PUBLIC __attribute__ ((visibility("default")))
+#else
+#define PLUGIN_PUBLIC
+#endif
+
+#define SYS_IOCTL(fd, cmd, arg) \
+	syscall(SYS_ioctl, (int)(fd), (unsigned long)(cmd), (void *)(arg))
+
+#define SIMPLE_CONVERT_IOCTL(fd, cmd, arg, __struc) ({  \
+	int __ret;                                      \
+	struct __struc *req = arg;                      \
+	uint32_t type = req->type;                      \
+	req->type = convert_type(type);                 \
+	__ret = SYS_IOCTL(fd, cmd, arg);                \
+	req->type = type;                               \
+	__ret;                                          \
+	})
+
+#ifndef min
+#define min(a, b) (((a) < (b)) ? (a) : (b))
+#endif
+
+#ifndef max
+#define max(a, b) (((a) > (b)) ? (a) : (b))
+#endif
+
+#define EXYNOS4_FIMC_DRV	"exynos4-fimc"
+#define EXYNOS4_FIMC_LITE_DRV	"exynos-fimc-lit"
+#define EXYNOS4_FIMC_IS_ISP_DRV	"exynos4-fimc-is"
+#define EXYNOS4_CAPTURE_CONF	"/var/lib/libv4l/exynos4_capture_conf"
+#define EXYNOS4_FIMC_IS_ISP	"FIMC-IS-ISP"
+#define EXYNOS4_S5K6A3		"S5K6A3"
+#define EXYNOS4_FIMC_LITE_PREFIX "FIMC-LITE."
+#define EXYNOS4_FIMC_PREFIX	"FIMC."
+#define EXYNOS4_MAX_FMT_NEGO_NUM 50
+#define EXYNOS4_MAX_PIPELINE_LEN 7
+
+struct media_device;
+struct media_entity;
+
+/*
+ * struct pipeline_entity - linked media device pipeline
+ * @entity:		linked entity
+ * @sink_pad:		inbound link pad of the entity
+ * @src_pad:		outbound link pad of the entity
+ */
+struct pipeline_entity {
+	struct media_entity *entity;
+	struct media_pad *sink_pad;
+	struct media_pad *src_pad;
+};
+
+/*
+ * struct media_entity_to_cid - entity to control map
+ * @entity:		media entity
+ * @sink_pad:		inbound link pad of the entity
+ * @src_pad:		outbound link pad of the entity
+ */
+struct media_entity_to_cid {
+	struct media_entity *entity;
+	union {
+		struct v4l2_queryctrl queryctrl;
+		struct v4l2_query_ext_ctrl query_ext_ctrl;
+	};
+};
+
+/*
+ * struct exynos4_camera_plugin - libv4l exynos4 camera plugin
+ * @media:		media device comprising the opened video device
+ * @pipeline:		video pipeline, element 0 is the source entity
+ * @pipeline_len:	length of the video pipeline
+ */
+struct exynos4_camera_plugin {
+	struct media_device *media;
+	struct pipeline_entity pipeline[EXYNOS4_MAX_PIPELINE_LEN];
+	unsigned int pipeline_len;
+};
+
+/* -----------------------------------------------------------------------------
+ * Pipeline operations
+ */
+
+/**
+ * @brief Discover video pipeline for given sink entity
+ * @param plugin - this plugin.
+ * @param entity - sink entity of the pipeline.
+ *
+ * Discover the video pipeline, by walking starting from the
+ * sink entity upwards until a source entity is encountered.
+ *
+ * @return 0 if the sensor entity was detected,
+ * 	   or negative error code on failure.
+ */
+static int discover_pipeline_by_entity(struct exynos4_camera_plugin *plugin,
+				       struct media_entity *entity)
+{
+	struct pipeline_entity reverse_pipeline[EXYNOS4_MAX_PIPELINE_LEN];
+	struct media_pad *src_pad;
+	struct media_link *link = NULL, *backlinks[2];
+	unsigned int num_backlinks, cur_pipe_pos = 0;
+	int i, j;
+	int ret;
+
+	if (entity == NULL)
+		return -EINVAL;
+
+	for (;;) {
+		/* Cache the recently discovered entity. */
+		reverse_pipeline[cur_pipe_pos].entity = entity;
+
+		/* Cache the source pad used for linking the entity. */
+		if (link)
+			reverse_pipeline[cur_pipe_pos].src_pad = link->source;
+
+		ret = media_entity_get_backlinks(entity, backlinks,
+						 &num_backlinks);
+		if (ret < 0)
+			return ret;
+
+		/* Check if pipeline source entity has been reached. */
+		if (num_backlinks > 2) {
+			V4L2_EXYNOS4_DBG("Unexpected number of busy sink pads (%d)",
+					 num_backlinks);
+			return -EINVAL;
+		} else if (num_backlinks == 2) {
+			/*
+			 * Allow two active pads only in case of
+			 * S5C73M3-OIF entity.
+			 */
+			if (strcmp(media_entity_get_info(entity)->name,
+				   "S5C73M3-OIF")) {
+				V4L2_EXYNOS4_DBG("Ambiguous media device topology: "
+						 "two busy sink pads");
+				return -EINVAL;
+			}
+			/*
+			 * Two active links are allowed betwen S5C73M3-OIF and
+			 * S5C73M3 entities. In such a case route through the
+			 * pad with id == 0 has to be chosen.
+			 */
+			link = NULL;
+			for (i = 0; i < num_backlinks; i++)
+				if (backlinks[i]->sink->index == 0)
+					link = backlinks[i];
+			if (link == NULL)
+				return -EINVAL;
+		} else if (num_backlinks == 1) {
+			link = backlinks[0];
+		} else {
+			reverse_pipeline[cur_pipe_pos].sink_pad = NULL;
+			break;
+		}
+
+		/* Cache the sink pad used for linking the entity. */
+		reverse_pipeline[cur_pipe_pos].sink_pad = link->sink;
+
+		V4L2_EXYNOS4_DBG("Discovered sink pad %d for the %s entity",
+				 reverse_pipeline[cur_pipe_pos].sink_pad->index,
+				 media_entity_get_info(entity)->name);
+
+		src_pad = media_entity_remote_source(link->sink);
+		if (!src_pad)
+			return -EINVAL;
+
+		entity = src_pad->entity;
+		if (++cur_pipe_pos == EXYNOS4_MAX_PIPELINE_LEN)
+			return -EINVAL;
+	}
+
+	/*
+	 * Reorder discovered pipeline elements so that the sensor
+	 * entity was the pipeline head.
+	 */
+	j = 0;
+	for (i = cur_pipe_pos; i >= 0; i--)
+		plugin->pipeline[j++] = reverse_pipeline[i];
+
+	plugin->pipeline_len = j;
+
+	return 0;
+}
+
+/**
+ * @brief Check if the entity belongs to the plugin video pipeline
+ * @param plugin - this plugin.
+ * @param entity_name - name of the entity to look for.
+ *
+ * Check if the entity belongs to the pipeline whose sink element
+ * is the video device represented by the file descriptor passed
+ * to plugin_init().
+ *
+ * @return True if the entity belongs to the pipeline,
+ *         and false otherwise.
+ */
+static bool has_pipeline_entity(struct exynos4_camera_plugin *plugin,
+				char *entity_name)
+{
+	struct pipeline_entity *pipeline = plugin->pipeline;
+	struct media_entity *entity;
+	unsigned int i;
+
+	if (pipeline == NULL || entity_name == NULL)
+		return -EINVAL;
+
+	for (i = 0; i < plugin->pipeline_len; i++) {
+		entity = pipeline[i].entity;
+		if (!strncmp(media_entity_get_info(entity)->name, entity_name,
+			     strlen(entity_name)))
+			return true;
+	}
+
+	return false;
+}
+
+/**
+ * @brief Adjust mbus format to FIMC_IS_ISP limitations.
+ * @param mbus_fmt - format to adjust.
+ *
+ * FIMC_IS_ISP shears the video frame off, effectively the format set
+ * on the preceding entities has to be suitably greater to achieve
+ * the frame size requested by the user.
+ *
+ * Also the miminum frame size supported by FIMC_IS_ISP is 128x128.
+ */
+static void adjust_format_to_fimc_is_isp(struct v4l2_mbus_framefmt *mbus_fmt)
+{
+	mbus_fmt->width = max(128, mbus_fmt->width);
+	mbus_fmt->height = max(128, mbus_fmt->height);
+
+	mbus_fmt->width += 16;
+	mbus_fmt->height += 12;
+}
+
+/**
+ * @brief Negotiate format acceptable for all pipeline entities.
+ * @param plugin - this plugin.
+ * @param dev_fmt - requested video device format.
+ *
+ * Negotiate common format acceptable by all the pipeline entities,
+ * that is closest to the requested one.
+ *
+ * @return 0 if the negotiation succeeded,
+ * 	   or negative error code on failure.
+ */
+static int negotiate_pipeline_fmt(struct exynos4_camera_plugin *plugin,
+				  struct v4l2_format *dev_fmt)
+{
+	struct v4l2_mbus_framefmt mbus_fmt = { 0 }, common_fmt;
+	int repeat_negotiation, cnt_negotiation = 0, ret, pad_id, i;
+	struct pipeline_entity *pipeline = plugin->pipeline;
+	enum v4l2_subdev_fmt_mismatch fmt_err;
+	struct media_entity *entity;
+
+	if (pipeline == NULL || dev_fmt == NULL)
+		return -EINVAL;
+
+	mbus_fmt.width = dev_fmt->fmt.pix_mp.width;
+	mbus_fmt.height = dev_fmt->fmt.pix_mp.height;
+	mbus_fmt.field = dev_fmt->fmt.pix_mp.field;
+	mbus_fmt.colorspace = dev_fmt->fmt.pix_mp.colorspace;
+
+	if (has_pipeline_entity(plugin, EXYNOS4_FIMC_IS_ISP))
+		adjust_format_to_fimc_is_isp(&mbus_fmt);
+
+	V4L2_EXYNOS4_DBG("Begin pipeline format negotiation...");
+
+	for (;;) {
+		repeat_negotiation = 0;
+		entity = pipeline[0].entity;
+
+		pad_id = pipeline[0].src_pad->index;
+
+		V4L2_EXYNOS4_DBG("Setting format on the source entity pad %s:%d",
+				 media_entity_get_info(entity)->name, pad_id);
+
+		ret = v4l2_subdev_set_format(entity, &mbus_fmt,
+					     pad_id, V4L2_SUBDEV_FORMAT_TRY);
+		if (ret < 0)
+			return ret;
+
+		V4L2_EXYNOS4_DBG("Format set on the pad %s:%d: mcode: %s, cs: %s, w: %d, h: %d",
+				 media_entity_get_info(entity)->name, pad_id,
+				 v4l2_subdev_pixelcode_to_string(mbus_fmt.code),
+				 v4l2_subdev_colorspace_to_string(mbus_fmt.colorspace),
+				 mbus_fmt.width, mbus_fmt.height);
+
+		common_fmt = mbus_fmt;
+
+		/* Stop iterating on last but one entity as it is not a sub-device. */
+		for (i = 1; i < plugin->pipeline_len - 1; i++) {
+			entity = pipeline[i].entity;
+
+			pad_id = pipeline[i].sink_pad->index;
+
+			V4L2_EXYNOS4_DBG("Setting format on the pad %s:%d: mcode: %s, cs: %s, w: %d, h: %d",
+					 media_entity_get_info(entity)->name, pad_id,
+					 v4l2_subdev_pixelcode_to_string(mbus_fmt.code),
+					 v4l2_subdev_colorspace_to_string(mbus_fmt.colorspace),
+					 mbus_fmt.width, mbus_fmt.height);
+
+			/* Set format on the entity sink pad. */
+			ret = v4l2_subdev_set_format(entity, &mbus_fmt, pad_id,
+							V4L2_SUBDEV_FORMAT_TRY);
+			if (ret < 0)
+				return ret;
+
+			fmt_err = v4l2_subdev_format_compare(&mbus_fmt, &common_fmt);
+			if (fmt_err) {
+				if (fmt_err == FMT_MISMATCH_WIDTH &&
+				     !strncmp(media_entity_get_info(entity)->name,
+					      EXYNOS4_FIMC_LITE_PREFIX,
+					      strlen(EXYNOS4_FIMC_LITE_PREFIX))) {
+					/*
+					 * Align width downwards, according to the FIMC-LITE
+					 * width step. Otherwise pipeline format negotiation
+					 * wouldn't succeed for widths excessing maximum sensor
+					 * frame width, which is probed by GStreamer, no matter
+					 * what actual frame size is to be set.
+					 */
+					mbus_fmt.width -= 8;
+				}
+				repeat_negotiation = 1;
+				break;
+			}
+
+			/*
+			 * Do not check format on FIMC.[n] source pad
+			 * and stop negotiation.
+			 */
+			if (!strncmp(media_entity_get_info(entity)->name,
+				     EXYNOS4_FIMC_PREFIX,
+				     strlen(EXYNOS4_FIMC_PREFIX)))
+				break;
+
+			pad_id = pipeline[i].src_pad->index;
+
+			/* Get format on the entity src pad */
+			ret = v4l2_subdev_get_format(entity, &mbus_fmt, pad_id,
+							V4L2_SUBDEV_FORMAT_TRY);
+			if (ret < 0)
+				return -EINVAL;
+
+			V4L2_EXYNOS4_DBG("Format propagated to the pad %s:%d: mcode: %s, cs: %s, w: %d, h: %d",
+					 media_entity_get_info(entity)->name, pad_id,
+					 v4l2_subdev_pixelcode_to_string(mbus_fmt.code),
+					 v4l2_subdev_colorspace_to_string(mbus_fmt.colorspace),
+					 mbus_fmt.width, mbus_fmt.height);
+
+			if (!strcmp(media_entity_get_info(entity)->name,
+				    EXYNOS4_FIMC_IS_ISP)) {
+				common_fmt.code = mbus_fmt.code;
+				common_fmt.colorspace = mbus_fmt.colorspace;
+				common_fmt.width -= 16;
+				common_fmt.height -= 12;
+			}
+
+			if (v4l2_subdev_format_compare(&mbus_fmt, &common_fmt)) {
+				repeat_negotiation = 1;
+				break;
+			}
+		}
+
+		if (!repeat_negotiation) {
+			break;
+		} else if (++cnt_negotiation > EXYNOS4_MAX_FMT_NEGO_NUM) {
+			V4L2_EXYNOS4_DBG("Pipeline format negotiation failed!");
+			return -EINVAL;
+		}
+	}
+
+	dev_fmt->fmt.pix_mp.width = mbus_fmt.width;
+	dev_fmt->fmt.pix_mp.height = mbus_fmt.height;
+	dev_fmt->fmt.pix_mp.field = mbus_fmt.field;
+	dev_fmt->fmt.pix_mp.colorspace = mbus_fmt.colorspace;
+
+	V4L2_EXYNOS4_DBG("Pipeline format successfuly negotiated");
+
+	return 0;
+}
+
+/**
+ * @brief Apply previously negotiated pipeline format
+ * @param plugin - this plugin.
+ *
+ * Apply the format, previously negotiated with negotiate_pipeline_fmt(),
+ * on all the pipeline v4l2 sub-devices.
+ *
+ * @return 0 if the format was successfuly applied,
+ * 	   or negative error code on failure.
+ */
+static int apply_pipeline_fmt(struct exynos4_camera_plugin *plugin,
+			      struct v4l2_format *fmt)
+{
+	struct v4l2_mbus_framefmt mbus_fmt = { 0 };
+	struct pipeline_entity *pipeline = plugin->pipeline;
+	struct media_entity *entity;
+	struct media_pad *pad;
+	unsigned int i;
+	int ret;
+
+	if (pipeline == NULL)
+		return -EINVAL;
+
+	for (i = 0; i < plugin->pipeline_len - 1; i++) {
+		entity = pipeline[i].entity;
+		/*
+		 * Source entity is linked only through a source pad
+		 * and this pad should be used for setting the format.
+		 * For other entities set the format on a sink pad.
+		 */
+		pad = pipeline[i].sink_pad ? pipeline[i].sink_pad :
+					pipeline[i].src_pad;
+		if (pad == NULL)
+			return -EINVAL;
+
+		ret = v4l2_subdev_get_format(entity, &mbus_fmt, pad->index,
+					     V4L2_SUBDEV_FORMAT_TRY);
+
+		if (ret < 0)
+			return ret;
+
+		V4L2_EXYNOS4_DBG("VIDIOC_SUBDEV_G_FMT %s:%d: mcode: %s, cs: %s, w: %d, h: %d",
+			  media_entity_get_info(entity)->name, pad->index,
+			  v4l2_subdev_pixelcode_to_string(mbus_fmt.code),
+			  v4l2_subdev_colorspace_to_string(mbus_fmt.colorspace),
+			  mbus_fmt.width, mbus_fmt.height);
+
+		ret = v4l2_subdev_set_format(entity, &mbus_fmt, pad->index,
+					     V4L2_SUBDEV_FORMAT_ACTIVE);
+		if (ret < 0)
+			return ret;
+
+		V4L2_EXYNOS4_DBG("VIDIOC_SUBDEV_S_FMT %s:%d: mcode: %s, cs: %s, w: %d, h: %d",
+			  media_entity_get_info(entity)->name, pad->index,
+			  v4l2_subdev_pixelcode_to_string(mbus_fmt.code),
+			  v4l2_subdev_colorspace_to_string(mbus_fmt.colorspace),
+			  mbus_fmt.width, mbus_fmt.height);
+	}
+
+	/*
+	 * Sink entity represents /dev/videoN node and is not
+	 * a sub-device. Nonetheless because it has associated
+	 * file descriptor and can expose v4l2-controls the
+	 * v4l2-subdev structure is used for caching the
+	 * related data.
+	 */
+	struct v4l2_subdev *sd =
+		media_entity_get_v4l2_subdev(pipeline[i].entity);
+	if (!sd)
+		return -EINVAL;
+
+	ret = SYS_IOCTL(sd->fd, VIDIOC_S_FMT, fmt);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+/**
+ * @brief Open all v4l2 sub-devices associated with pipeline entities
+ * @param plugin - this plugin.
+ *
+ * Open all v4l2 sub-devices associated with the entities of the pipeline
+ * discovered with discover_pipeline_by_entity().
+ *
+ * @return 0 if all v4l2 sub-devices were opened successfuly,
+ * 	   or negative error code on failure.
+ */
+static int open_pipeline(struct exynos4_camera_plugin *plugin)
+{
+	struct pipeline_entity *pipeline = plugin->pipeline;
+	struct media_entity *entity;
+	unsigned int i;
+	int ret;
+
+	if (pipeline == NULL)
+		return -EINVAL;
+
+	/*
+	 * Stop walking the pipeline on the last but one entity, because
+	 * the sink entity was already opened by libv4l2 core.
+	 */
+	for (i = 0; i < plugin->pipeline_len - 1; i++) {
+		entity = pipeline[i].entity;
+		V4L2_EXYNOS4_DBG("Opening sub-device: %s",
+				 media_entity_get_info(entity)->name);
+		ret = v4l2_subdev_open(entity);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * @brief Check if there was a v4l2_ctrl binding defined for the entity
+ * @param entity - media entity.
+ * @param ctrl_id - v4l2 control identifier.
+ *
+ * Check if there was a v4l2-ctrl-binding entry defined for the entity.
+ *
+ * @return true if the binding exists, false otherwise.
+ */
+static bool has_v4l2_ctrl_binding(struct media_entity *entity,
+				       int ctrl_id)
+{
+	struct v4l2_subdev *sd = media_entity_get_v4l2_subdev(entity);
+	int i;
+
+	if (!sd)
+		return false;
+
+	for (i = 0; i < sd->num_v4l2_ctrl_bindings; ++i)
+		if (sd->v4l2_ctrl_bindings[i] == ctrl_id)
+			return true;
+
+	return false;
+}
+
+/**
+ * @brief Get the first pipeline entity with matching v4l2-ctrl-binding.
+ * @param plugin - this plugin.
+ * @param cid - v4l2-control identifier.
+ *
+ * Get the first pipeline entity for which v4l2-control-binding
+ * with given cid was defined.
+ *
+ * @return associated entity if defined, or NULL if no matching
+ *         v4l2-ctrl-binding was defined for any entity
+ *         in the pipeline.
+ */
+static struct media_entity *get_pipeline_entity_by_cid(
+				struct exynos4_camera_plugin *plugin,
+				int cid)
+{
+	struct pipeline_entity *pipeline = plugin->pipeline;
+	struct media_entity *entity;
+	unsigned int i;
+
+	if (pipeline == NULL)
+		return NULL;
+
+	for (i = 0; i < plugin->pipeline_len; i++) {
+		entity = pipeline[i].entity;
+		if (has_v4l2_ctrl_binding(entity, cid))
+			return entity;
+	}
+
+	return NULL;
+}
+
+/**
+ * @brief Check if the entity is of capture type
+ * @param entity_name - name of the entity to check
+ *
+ * Check if the entity name ends with a "capture", which
+ * gives a hint that it is of capture type.
+ *
+ * @return True if the entity name ends with a "capture"
+ *         string, and false otherwise.
+ */
+static bool is_capture_entity(const char *entity_name)
+{
+	const char capture_segment[] = "capture";
+	int cap_segment_pos;
+
+	if (entity_name == NULL)
+		return false;
+
+	cap_segment_pos = strlen(entity_name) - strlen(capture_segment);
+
+	if (strcmp(entity_name + cap_segment_pos, capture_segment) == 0)
+		return true;
+
+	return false;
+}
+
+static __u32 convert_type(__u32 type)
+{
+	switch (type) {
+	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
+		return V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+	default:
+		return type;
+	}
+}
+
+/* -----------------------------------------------------------------------------
+ * Ioctl handlers
+ */
+
+static int set_fmt_ioctl(struct exynos4_camera_plugin *plugin,
+				unsigned long int cmd,
+				struct v4l2_format *arg,
+				enum v4l2_subdev_format_whence set_mode)
+{
+	struct v4l2_format fmt = { 0 };
+	int ret;
+
+	fmt.type = convert_type(arg->type);
+	if (fmt.type != arg->type) {
+		fmt.fmt.pix_mp.width = arg->fmt.pix.width;
+		fmt.fmt.pix_mp.height = arg->fmt.pix.height;
+		fmt.fmt.pix_mp.pixelformat = arg->fmt.pix.pixelformat;
+		fmt.fmt.pix_mp.field = arg->fmt.pix.field;
+		fmt.fmt.pix_mp.colorspace = arg->fmt.pix.colorspace;
+		fmt.fmt.pix_mp.num_planes = 1;
+		fmt.fmt.pix_mp.flags = arg->fmt.pix.flags;
+		fmt.fmt.pix_mp.plane_fmt[0].bytesperline = arg->fmt.pix.bytesperline;
+		fmt.fmt.pix_mp.plane_fmt[0].sizeimage = arg->fmt.pix.sizeimage;
+	} else {
+		fmt = *arg;
+	}
+
+	ret = negotiate_pipeline_fmt(plugin, &fmt);
+	if (ret < 0)
+		return ret;
+
+	if (set_mode == V4L2_SUBDEV_FORMAT_ACTIVE) {
+		ret = apply_pipeline_fmt(plugin, &fmt);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (fmt.type != arg->type) {
+		arg->fmt.pix.width = fmt.fmt.pix_mp.width;
+		arg->fmt.pix.height = fmt.fmt.pix_mp.height;
+		arg->fmt.pix.pixelformat = fmt.fmt.pix_mp.pixelformat;
+		arg->fmt.pix.field = fmt.fmt.pix_mp.field;
+		arg->fmt.pix.colorspace = fmt.fmt.pix_mp.colorspace;
+		arg->fmt.pix.bytesperline = fmt.fmt.pix_mp.plane_fmt[0].bytesperline;
+		arg->fmt.pix.sizeimage = fmt.fmt.pix_mp.plane_fmt[0].sizeimage;
+		arg->fmt.pix.flags = fmt.fmt.pix_mp.flags;
+	} else {
+		*arg = fmt;
+	}
+
+	return 0;
+}
+
+static int get_fmt_ioctl(int fd,
+			 unsigned long int cmd,
+			 struct v4l2_format *arg)
+{
+	struct v4l2_format fmt = { 0 };
+	int ret;
+
+	fmt.type = convert_type(arg->type);
+
+	if (fmt.type == arg->type)
+		return SYS_IOCTL(fd, cmd, arg);
+
+	ret = SYS_IOCTL(fd, cmd, &fmt);
+	if (ret < 0)
+		return ret;
+
+	memset(&arg->fmt.pix, 0, sizeof(arg->fmt.pix));
+	arg->fmt.pix.width = fmt.fmt.pix_mp.width;
+	arg->fmt.pix.height = fmt.fmt.pix_mp.height;
+	arg->fmt.pix.pixelformat = fmt.fmt.pix_mp.pixelformat;
+	arg->fmt.pix.field = fmt.fmt.pix_mp.field;
+	arg->fmt.pix.colorspace = fmt.fmt.pix_mp.colorspace;
+	arg->fmt.pix.bytesperline = fmt.fmt.pix_mp.plane_fmt[0].bytesperline;
+	arg->fmt.pix.sizeimage = fmt.fmt.pix_mp.plane_fmt[0].sizeimage;
+	arg->fmt.pix.flags = fmt.fmt.pix_mp.flags;
+
+	return ret;
+}
+
+static int buf_ioctl(int fd,
+		     unsigned long int cmd,
+		     struct v4l2_buffer *arg)
+{
+	struct v4l2_buffer buf = *arg;
+	struct v4l2_plane plane = { 0 };
+	int ret;
+
+	buf.type = convert_type(arg->type);
+
+	if (buf.type == arg->type)
+		return SYS_IOCTL(fd, cmd, arg);
+
+	memcpy(&plane.m, &arg->m, sizeof(plane.m));
+	plane.length = arg->length;
+	plane.bytesused = arg->bytesused;
+
+	buf.m.planes = &plane;
+	buf.length = 1;
+
+	ret = SYS_IOCTL(fd, cmd, &buf);
+
+	arg->index = buf.index;
+	arg->memory = buf.memory;
+	arg->flags = buf.flags;
+	arg->field = buf.field;
+	arg->timestamp = buf.timestamp;
+	arg->timecode = buf.timecode;
+	arg->sequence = buf.sequence;
+
+	arg->length = plane.length;
+	arg->bytesused = plane.bytesused;
+	memcpy(&arg->m, &plane.m, sizeof(arg->m));
+
+	return ret;
+}
+
+static int querycap_ioctl(int fd, struct v4l2_capability *arg)
+{
+	int ret;
+
+	ret = SYS_IOCTL(fd, VIDIOC_QUERYCAP, arg);
+	if (ret < 0)
+		return ret;
+
+	arg->device_caps |= V4L2_CAP_VIDEO_CAPTURE;
+	arg->capabilities |= V4L2_CAP_VIDEO_CAPTURE;
+
+	return ret;
+}
+
+int ctrl_ioctl(struct exynos4_camera_plugin *plugin,
+	       unsigned long int request, struct v4l2_control *arg)
+{
+	struct pipeline_entity *pipeline = plugin->pipeline;
+	struct media_entity *entity;
+	struct v4l2_control ctrl = *arg;
+	struct v4l2_queryctrl queryctrl = { 0 };
+	bool ctrl_found = false;
+	int i, ret;
+
+	if (pipeline == NULL)
+		return -EINVAL;
+
+	/*
+	 * The control has to be reset to the default value
+	 * on all of the pipeline entities, prior setting a new
+	 * value. This is required in cases when the control config
+	 * is changed between subsequent calls to VIDIOC_S_CTRL,
+	 * to avoid the situation when a control is set on more
+	 * than one sub-device.
+	 */
+	if (request == VIDIOC_S_CTRL) {
+		for (i = 0; i < plugin->pipeline_len; i++) {
+			struct v4l2_control ctrl_def = ctrl;
+
+			entity = pipeline[i].entity;
+
+			queryctrl.id = ctrl.id;
+
+			/* query default control value */
+			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
+					VIDIOC_QUERYCTRL, &queryctrl);
+			if (ret < 0)
+				continue;
+
+			ctrl_found = true;
+
+			if (queryctrl.type & V4L2_CTRL_TYPE_BUTTON)
+				break;
+
+			ctrl_def.value = queryctrl.default_value;
+			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
+					VIDIOC_S_CTRL, &ctrl_def);
+			if (ret < 0)
+				return -EINVAL;
+		}
+
+		if (!ctrl_found) {
+			ret = -EINVAL;
+			goto exit;
+		}
+	}
+
+	entity = get_pipeline_entity_by_cid(plugin, ctrl.id);
+
+	if (entity) {
+		ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
+				request, &ctrl);
+	} else {
+		/* Walk the pipeline until the request succeeds */
+		ret = -ENOENT;
+
+		for (i = 0; i < plugin->pipeline_len; i++) {
+			entity = pipeline[i].entity;
+
+			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
+					request, &ctrl);
+			if (!ret)
+				break;
+		}
+	}
+
+exit:
+	*arg = ctrl;
+
+	V4L2_EXYNOS4_DBG("%s [id: 0x%8.8x, name: %s, entity: %s] (%d)",
+			 VIDIOC_CTRL(request), ctrl.id,
+			 ret ? NULL : queryctrl.name,
+			 entity ? media_entity_get_info(entity)->name :
+				  NULL, ret);
+
+
+	return ret;
+}
+
+static int single_ext_ctrl_ioctl(struct exynos4_camera_plugin *plugin,
+				 unsigned long int request,
+				 struct v4l2_ext_controls *arg)
+{
+	struct pipeline_entity *pipeline = plugin->pipeline;
+	struct media_entity *entity;
+	struct v4l2_ext_controls ctrls = *arg;
+	struct v4l2_ext_control *ctrl = &ctrls.controls[0];
+	struct v4l2_query_ext_ctrl queryctrl;
+	bool ctrl_found = 0;
+	int i, ret = -EINVAL;
+
+	/*
+	 * The control has to be reset to the default value
+	 * on all of the pipeline entities, prior setting a new
+	 * value. This is required in cases when the control config
+	 * is changed between subsequent calls to VIDIOC_S_EXT_CTRLS,
+	 * to avoid the situation when a control is set on more
+	 * than one sub-device.
+	 */
+	if (request == VIDIOC_S_EXT_CTRLS) {
+		for (i = 0; i < plugin->pipeline_len; i++) {
+			struct v4l2_ext_controls ctrls_def = ctrls;
+			struct v4l2_ext_control *ctrl_def = &ctrls_def.controls[0];
+
+			entity = pipeline[i].entity;
+
+			queryctrl.id = ctrl->id;
+
+			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
+					VIDIOC_QUERY_EXT_CTRL, &queryctrl);
+			if (ret < 0)
+				continue;
+
+			ctrl_found = true;
+
+			if (queryctrl.type & V4L2_CTRL_TYPE_BUTTON)
+				break;
+
+			ctrl_def->value64 = queryctrl.default_value;
+
+			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
+					VIDIOC_S_EXT_CTRLS, &ctrls_def);
+			if (ret < 0)
+				return -EINVAL;
+		}
+
+		if (!ctrl_found) {
+			ret = -EINVAL;
+			goto exit;
+		}
+	}
+
+	entity = get_pipeline_entity_by_cid(plugin, ctrl->id);
+
+	if (entity) {
+		ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
+				request, &ctrls);
+	} else {
+		/* Walk the pipeline until the request succeeds */
+		for (i = 0; i < plugin->pipeline_len; i++) {
+			entity = pipeline[i].entity;
+
+			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
+					request, &ctrls);
+			if (!ret)
+				break;
+		}
+	}
+
+exit:
+	*arg = ctrls;
+
+	V4L2_EXYNOS4_DBG("%s [id: 0x%8.8x, name: %s, entity: %s] (%d)",
+			 VIDIOC_CTRL(request), ctrl->id,
+			 ret ? NULL : queryctrl.name,
+			 entity ? media_entity_get_info(entity)->name :
+				  NULL, ret);
+
+	return ret;
+}
+
+int ext_ctrl_ioctl(struct exynos4_camera_plugin *plugin,
+		   unsigned long int request,
+		   struct v4l2_ext_controls *arg)
+{
+	struct v4l2_ext_controls out_ctrls = *arg, ctrls = *arg;
+	int ret = -EINVAL, i;
+
+	ctrls.count = 1;
+
+	/*
+	 * Split cluster to individual ioctl calls for each control
+	 * from the array, to make possible redirection of every
+	 * single control to different sub-device, according to the
+	 * configuration settings.
+	 */
+	for (i = 0; i < arg->count; ++i) {
+		ctrls.controls = &arg->controls[i];
+
+		ret = single_ext_ctrl_ioctl(plugin, request, &ctrls);
+		out_ctrls.controls[i] = ctrls.controls[i];
+		if (ret < 0) {
+			if (ctrls.error_idx == 1)
+				out_ctrls.error_idx = ctrls.count;
+			else
+				out_ctrls.error_idx = i;
+			break;
+		}
+	}
+
+	*arg = out_ctrls;
+	return ret;
+}
+
+int sort_ctrls(const void * a, const void * b)
+{
+	const struct media_entity_to_cid *ctrl_a = a, *ctrl_b = b;
+
+	return ctrl_a->queryctrl.id - ctrl_b->queryctrl.id;
+}
+
+int queryctrl_ioctl(struct exynos4_camera_plugin *plugin,
+		    struct v4l2_queryctrl *arg)
+{
+	struct pipeline_entity *pipeline = plugin->pipeline;
+	struct media_entity *entity, *target_entity;
+	struct v4l2_queryctrl queryctrl = *arg;
+	struct media_entity_to_cid *ctrls_found;
+	int i, ret = -EINVAL, num_ctrls = 0;
+
+	/*
+	 * If id is or'ed with V4L2_CTRL_FLAG_NEXT_CTRL then the control to
+	 * be found is the one with the next lowest id among all entities
+	 * in the pipeline.
+	 */
+	if (queryctrl.id & V4L2_CTRL_FLAG_NEXT_CTRL) {
+		ctrls_found = malloc(sizeof(*ctrls_found));
+
+		for (i = 0; i < plugin->pipeline_len; i++) {
+			entity = pipeline[i].entity;
+
+			queryctrl = *arg;
+
+			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
+					VIDIOC_QUERYCTRL, &queryctrl);
+			if (!ret) {
+				ctrls_found = realloc(ctrls_found,
+					sizeof(*ctrls_found) * (num_ctrls + 1));
+				ctrls_found[num_ctrls].queryctrl = queryctrl;
+				ctrls_found[num_ctrls].entity = entity;
+				++num_ctrls;
+			}
+		}
+
+		if (num_ctrls == 0) {
+			ret = -EINVAL;
+			entity = NULL;
+			goto done;
+		}
+
+		qsort(ctrls_found, num_ctrls, sizeof(*ctrls_found), sort_ctrls);
+
+		queryctrl = ctrls_found[0].queryctrl;
+		target_entity = ctrls_found[0].entity;
+
+		free(ctrls_found);
+	}
+
+	entity = get_pipeline_entity_by_cid(plugin, queryctrl.id);
+	if (entity)
+		target_entity = entity;
+
+	ret = SYS_IOCTL(media_entity_get_v4l2_subdev(target_entity)->fd,
+			VIDIOC_QUERYCTRL, &queryctrl);
+
+done:
+	V4L2_EXYNOS4_DBG(
+		"VIDIOC_QUERYCTRL [id: 0x%8.8x, name: %s, entity: %s] (%d)",
+		ret ? arg->id : queryctrl.id, ret ? NULL : queryctrl.name,
+		target_entity ? media_entity_get_info(target_entity)->name :
+				NULL, ret);
+
+	*arg = queryctrl;
+
+	return ret;
+}
+
+int query_ext_ctrl_ioctl(struct exynos4_camera_plugin *plugin,
+			 struct v4l2_query_ext_ctrl *arg)
+{
+	struct pipeline_entity *pipeline = plugin->pipeline;
+	struct media_entity *entity, *target_entity;
+	struct v4l2_query_ext_ctrl query_ext_ctrl = *arg;
+	struct media_entity_to_cid *ctrls_found;
+	int i, ret = -EINVAL, num_ctrls = 0;
+
+	/*
+	 * If id is or'ed with V4L2_CTRL_FLAG_NEXT_CTRL then the control to
+	 * be found is the one with the next lowest id among all entities
+	 * in the pipeline.
+	 */
+	if (query_ext_ctrl.id & V4L2_CTRL_FLAG_NEXT_CTRL) {
+		ctrls_found = malloc(sizeof(*ctrls_found));
+
+		for (i = 0; i < plugin->pipeline_len; i++) {
+			entity = pipeline[i].entity;
+
+			query_ext_ctrl = *arg;
+
+			ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
+					VIDIOC_QUERY_EXT_CTRL, &query_ext_ctrl.id);
+			if (!ret) {
+				ctrls_found = realloc(ctrls_found,
+					sizeof(*ctrls_found) * (num_ctrls + 1));
+				ctrls_found[num_ctrls].query_ext_ctrl =
+								query_ext_ctrl;
+				ctrls_found[num_ctrls].entity = entity;
+				++num_ctrls;
+			}
+		}
+
+		if (num_ctrls == 0) {
+			ret = -EINVAL;
+			entity = NULL;
+			goto done;
+		}
+
+		qsort(ctrls_found, num_ctrls, sizeof(*ctrls_found), sort_ctrls);
+
+		query_ext_ctrl = ctrls_found[0].query_ext_ctrl;
+		target_entity = ctrls_found[0].entity;
+
+		free(ctrls_found);
+	}
+
+	entity = get_pipeline_entity_by_cid(plugin, query_ext_ctrl.id);
+	if (entity)
+		target_entity = entity;
+
+	ret = SYS_IOCTL(media_entity_get_v4l2_subdev(target_entity)->fd,
+			VIDIOC_QUERYCTRL, &query_ext_ctrl);
+
+done:
+	V4L2_EXYNOS4_DBG(
+		"VIDIOC_QUERY_EXT_CTRL [id: 0x%8.8x, name: %s, entity: %s] (%d)",
+		ret ? arg->id : query_ext_ctrl.id,
+		ret ? NULL : query_ext_ctrl.name,
+		target_entity ? media_entity_get_info(target_entity)->name :
+				NULL, ret);
+
+	*arg = query_ext_ctrl;
+
+	return ret;
+}
+
+int querymenu_ioctl(struct exynos4_camera_plugin *plugin,
+		    struct v4l2_querymenu *arg)
+{
+	struct pipeline_entity *pipeline = plugin->pipeline;
+	struct media_entity *entity;
+	struct v4l2_querymenu querymenu = *arg;
+	int i, ret = -EINVAL;
+
+	entity = get_pipeline_entity_by_cid(plugin, querymenu.id);
+	if (entity) {
+		ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
+			        VIDIOC_QUERYMENU, &querymenu);
+		goto exit;
+	}
+
+	for (i = 0; i < plugin->pipeline_len; i++) {
+		entity = pipeline[i].entity;
+
+		ret = SYS_IOCTL(media_entity_get_v4l2_subdev(entity)->fd,
+				VIDIOC_QUERYMENU, &querymenu);
+		if (!ret)
+			break;
+	}
+
+exit:
+	*arg = querymenu;
+
+	V4L2_EXYNOS4_DBG(
+		"VIDIOC_QUERYMENU [id: 0x%8.8x, name: %s, entity: %s] (%d)",
+		querymenu.id, ret ? NULL : querymenu.name,
+		entity ? media_entity_get_info(entity)->name : NULL, ret);
+
+	return ret;
+}
+
+static void *plugin_init(int fd)
+{
+	struct v4l2_capability cap = { 0 };
+	struct exynos4_camera_plugin *plugin = NULL;
+	const char *sink_entity_name;
+	struct media_device *media;
+	struct media_entity *sink_entity;
+	int ret;
+
+	ret = SYS_IOCTL(fd, VIDIOC_QUERYCAP, &cap);
+	if (ret < 0) {
+		V4L2_EXYNOS4_ERR("Failed to query video capabilities.");
+		return NULL;
+	}
+
+	/* Check if this is Exynos4 media device */
+	if (strcmp((char *) cap.driver, EXYNOS4_FIMC_DRV) &&
+	    strcmp((char *) cap.driver, EXYNOS4_FIMC_LITE_DRV) &&
+	    strcmp((char *) cap.driver, EXYNOS4_FIMC_IS_ISP_DRV)) {
+		V4L2_EXYNOS4_ERR("Not an Exynos4 media device.");
+		return NULL;
+	}
+
+	/*
+	 * Create a representation of the media device
+	 * containing the opened video device.
+	 */
+	media = media_device_new_by_subdev_fd(fd, &sink_entity);
+	if (media == NULL) {
+		V4L2_EXYNOS4_ERR("Failed to create media device.");
+		return NULL;
+	}
+
+#ifdef DEBUG
+	media_debug_set_handler(media, (void (*)(void *, ...))fprintf, stdout);
+#endif
+
+	sink_entity_name = media_entity_get_info(sink_entity)->name;
+
+	/* Check if video entity is of capture type, not m2m */
+	if (!is_capture_entity(sink_entity_name)) {
+		V4L2_EXYNOS4_ERR("Device not of capture type.");
+		goto err_get_sink_entity;
+	}
+
+	/*
+	 * Initialize sink_entity subdev fd with the one opened
+	 * by the libv4l core to avoid losing it on pipeline opening.
+	 */
+	v4l2_subdev_create_opened(sink_entity, fd);
+
+	/* Parse media configuration file and apply its settings */
+	ret = mediatext_parse_setup_config(media, EXYNOS4_CAPTURE_CONF);
+	if (ret < 0) {
+		V4L2_EXYNOS4_ERR("Media config parser error.");
+		goto err_get_sink_entity;
+	}
+
+	/* Allocate private data */
+	plugin = calloc(1, sizeof(*plugin));
+	if (!plugin)
+		goto err_get_sink_entity;
+
+	plugin->media = media;
+
+	/*
+	 * Discover the pipeline of sub-devices from a camera sensor
+	 * to the opened video device.
+	 */
+	ret = discover_pipeline_by_entity(plugin, sink_entity);
+	if (ret < 0) {
+		V4L2_EXYNOS4_ERR("Error discovering video pipeline.");
+		goto err_discover_pipeline;
+	}
+
+	/* Open all sub-devices in the discovered pipeline */
+	ret = open_pipeline(plugin);
+	if (ret < 0) {
+		V4L2_EXYNOS4_ERR("Error opening video pipeline.");
+		goto err_discover_pipeline;
+	}
+
+	V4L2_EXYNOS4_LOG("Initialized exynos4-camera plugin.");
+
+	return plugin;
+
+err_discover_pipeline:
+	free(plugin);
+err_get_sink_entity:
+	if (media)
+		media_device_unref(media);
+	return NULL;
+}
+
+static void plugin_close(void *dev_ops_priv)
+{
+	struct exynos4_camera_plugin *plugin = dev_ops_priv;
+
+	if (plugin == NULL)
+		return;
+
+	media_device_unref(plugin->media);
+
+	free(plugin);
+}
+
+static int plugin_ioctl(void *dev_ops_priv, int fd, unsigned long int cmd,
+			void *arg)
+{
+	struct exynos4_camera_plugin *plugin = dev_ops_priv;
+
+	if (plugin == NULL || arg == NULL)
+		return -EINVAL;
+
+	switch (cmd) {
+	case VIDIOC_S_CTRL:
+	case VIDIOC_G_CTRL:
+		return ctrl_ioctl(plugin, cmd, arg);
+	case VIDIOC_S_EXT_CTRLS:
+	case VIDIOC_G_EXT_CTRLS:
+	case VIDIOC_TRY_EXT_CTRLS:
+		return ext_ctrl_ioctl(plugin, cmd, arg);
+	case VIDIOC_QUERYCTRL:
+		return queryctrl_ioctl(plugin, arg);
+	case VIDIOC_QUERY_EXT_CTRL:
+		return query_ext_ctrl_ioctl(plugin, arg);
+	case VIDIOC_QUERYMENU:
+		return querymenu_ioctl(plugin, arg);
+	case VIDIOC_TRY_FMT:
+		return set_fmt_ioctl(plugin, cmd, arg,
+				     V4L2_SUBDEV_FORMAT_TRY);
+	case VIDIOC_S_FMT:
+		return set_fmt_ioctl(plugin, cmd, arg,
+				     V4L2_SUBDEV_FORMAT_ACTIVE);
+	case VIDIOC_G_FMT:
+		return get_fmt_ioctl(fd, cmd, arg);
+	case VIDIOC_QUERYCAP:
+		return querycap_ioctl(fd, arg);
+	case VIDIOC_QBUF:
+	case VIDIOC_DQBUF:
+	case VIDIOC_QUERYBUF:
+	case VIDIOC_PREPARE_BUF:
+		return buf_ioctl(fd, cmd, arg);
+	case VIDIOC_REQBUFS:
+		return SIMPLE_CONVERT_IOCTL(fd, cmd, arg,
+					    v4l2_requestbuffers);
+	case VIDIOC_ENUM_FMT:
+		return SIMPLE_CONVERT_IOCTL(fd, cmd, arg, v4l2_fmtdesc);
+	case VIDIOC_CROPCAP:
+		return SIMPLE_CONVERT_IOCTL(fd, cmd, arg, v4l2_cropcap);
+	case VIDIOC_STREAMON:
+	case VIDIOC_STREAMOFF:
+		{
+			int *arg_type = (int *) arg;
+			__u32 type;
+
+			type = convert_type(*arg_type);
+
+			if (type != V4L2_BUF_TYPE_VIDEO_CAPTURE &&
+			    type != V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE) {
+				V4L2_EXYNOS4_ERR("Invalid buffer type.");
+				return -EINVAL;
+			}
+
+			return SYS_IOCTL(fd, cmd, &type);
+		}
+
+	default:
+		return SYS_IOCTL(fd, cmd, arg);
+	}
+}
+
+PLUGIN_PUBLIC const struct libv4l_dev_ops libv4l2_plugin = {
+	.init = &plugin_init,
+	.close = &plugin_close,
+	.ioctl = &plugin_ioctl,
+};