summaryrefslogtreecommitdiffstats
path: root/drivers/media/video/v4l2-fh.c
blob: 717f71e6370e564deb08371fb2b72bf326ee3bad (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
/*
 * v4l2-fh.c
 *
 * V4L2 file handles.
 *
 * Copyright (C) 2009--2010 Nokia Corporation.
 *
 * Contact: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * 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
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#include <linux/bitops.h>
#include <linux/slab.h>
#include <media/v4l2-dev.h>
#include <media/v4l2-fh.h>
#include <media/v4l2-event.h>
#include <media/v4l2-ioctl.h>

int v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev)
{
	fh->vdev = vdev;
	INIT_LIST_HEAD(&fh->list);
	set_bit(V4L2_FL_USES_V4L2_FH, &fh->vdev->flags);
	fh->prio = V4L2_PRIORITY_UNSET;

	/*
	 * fh->events only needs to be initialized if the driver
	 * supports the VIDIOC_SUBSCRIBE_EVENT ioctl.
	 */
	if (vdev->ioctl_ops && vdev->ioctl_ops->vidioc_subscribe_event)
		return v4l2_event_init(fh);

	fh->events = NULL;

	return 0;
}
EXPORT_SYMBOL_GPL(v4l2_fh_init);

void v4l2_fh_add(struct v4l2_fh *fh)
{
	unsigned long flags;

	if (test_bit(V4L2_FL_USE_FH_PRIO, &fh->vdev->flags))
		v4l2_prio_open(fh->vdev->prio, &fh->prio);
	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
	list_add(&fh->list, &fh->vdev->fh_list);
	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
}
EXPORT_SYMBOL_GPL(v4l2_fh_add);

int v4l2_fh_open(struct file *filp)
{
	struct video_device *vdev = video_devdata(filp);
	struct v4l2_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);

	filp->private_data = fh;
	if (fh == NULL)
		return -ENOMEM;
	v4l2_fh_init(fh, vdev);
	v4l2_fh_add(fh);
	return 0;
}
EXPORT_SYMBOL_GPL(v4l2_fh_open);

void v4l2_fh_del(struct v4l2_fh *fh)
{
	unsigned long flags;

	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
	list_del_init(&fh->list);
	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
	if (test_bit(V4L2_FL_USE_FH_PRIO, &fh->vdev->flags))
		v4l2_prio_close(fh->vdev->prio, fh->prio);
}
EXPORT_SYMBOL_GPL(v4l2_fh_del);

void v4l2_fh_exit(struct v4l2_fh *fh)
{
	if (fh->vdev == NULL)
		return;

	fh->vdev = NULL;

	v4l2_event_free(fh);
}
EXPORT_SYMBOL_GPL(v4l2_fh_exit);

int v4l2_fh_release(struct file *filp)
{
	struct v4l2_fh *fh = filp->private_data;

	if (fh) {
		v4l2_fh_del(fh);
		v4l2_fh_exit(fh);
		kfree(fh);
	}
	return 0;
}
EXPORT_SYMBOL_GPL(v4l2_fh_release);

int v4l2_fh_is_singular(struct v4l2_fh *fh)
{
	unsigned long flags;
	int is_singular;

	if (fh == NULL || fh->vdev == NULL)
		return 0;
	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
	is_singular = list_is_singular(&fh->list);
	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
	return is_singular;
}
EXPORT_SYMBOL_GPL(v4l2_fh_is_singular);