path: root/drivers/media/v4l2-core/v4l2-subdev.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * V4L2 sub-device
 *
 * Copyright (C) 2010 Nokia Corporation
 *
 * Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
 *	    Sakari Ailus <sakari.ailus@iki.fi>
 */

#include <linux/export.h>
#include <linux/ioctl.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/version.h>
#include <linux/videodev2.h>

#include <media/v4l2-ctrls.h>
#include <media/v4l2-device.h>
#include <media/v4l2-event.h>
#include <media/v4l2-fh.h>
#include <media/v4l2-ioctl.h>

#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
/*
 * The Streams API is an experimental feature. To use the Streams API, set
 * 'v4l2_subdev_enable_streams_api' to 1 below.
 */

static bool v4l2_subdev_enable_streams_api;
#endif

/*
 * Maximum stream ID is 63 for now, as we use u64 bitmask to represent a set
 * of streams.
 *
 * Note that V4L2_FRAME_DESC_ENTRY_MAX is related: V4L2_FRAME_DESC_ENTRY_MAX
 * restricts the total number of streams in a pad, although the stream ID is
 * not restricted.
 */
#define V4L2_SUBDEV_MAX_STREAM_ID 63

#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
static int subdev_fh_init(struct v4l2_subdev_fh *fh, struct v4l2_subdev *sd)
{
	struct v4l2_subdev_state *state;
	static struct lock_class_key key;

	state = __v4l2_subdev_state_alloc(sd, "fh->state->lock", &key);
	if (IS_ERR(state))
		return PTR_ERR(state);

	fh->state = state;

	return 0;
}

static void subdev_fh_free(struct v4l2_subdev_fh *fh)
{
	__v4l2_subdev_state_free(fh->state);
	fh->state = NULL;
}

static int subdev_open(struct file *file)
{
	struct video_device *vdev = video_devdata(file);
	struct v4l2_subdev *sd = vdev_to_v4l2_subdev(vdev);
	struct v4l2_subdev_fh *subdev_fh;
	int ret;

	subdev_fh = kzalloc(sizeof(*subdev_fh), GFP_KERNEL);
	if (subdev_fh == NULL)
		return -ENOMEM;

	ret = subdev_fh_init(subdev_fh, sd);
	if (ret) {
		kfree(subdev_fh);
		return ret;
	}

	v4l2_fh_init(&subdev_fh->vfh, vdev);
	v4l2_fh_add(&subdev_fh->vfh);
	file->private_data = &subdev_fh->vfh;

	if (sd->v4l2_dev->mdev && sd->entity.graph_obj.mdev->dev) {
		struct module *owner;

		owner = sd->entity.graph_obj.mdev->dev->driver->owner;
		if (!try_module_get(owner)) {
			ret = -EBUSY;
			goto err;
		}
		subdev_fh->owner = owner;
	}

	if (sd->internal_ops && sd->internal_ops->open) {
		ret = sd->internal_ops->open(sd, subdev_fh);
		if (ret < 0)
			goto err;
	}

	return 0;

err:
	module_put(subdev_fh->owner);
	v4l2_fh_del(&subdev_fh->vfh);
	v4l2_fh_exit(&subdev_fh->vfh);
	subdev_fh_free(subdev_fh);
	kfree(subdev_fh);

	return ret;
}

static int subdev_close(struct file *file)
{
	struct video_device *vdev = video_devdata(file);
	struct v4l2_subdev *sd = vdev_to_v4l2_subdev(vdev);
	struct v4l2_fh *vfh = file->private_data;
	struct v4l2_subdev_fh *subdev_fh = to_v4l2_subdev_fh(vfh);

	if (sd->internal_ops && sd->internal_ops->close