1/*
2 * v4l2-fh.c
3 *
4 * V4L2 file handles.
5 *
6 * Copyright (C) 2009--2010 Nokia Corporation.
7 *
8 * Contact: Sakari Ailus <sakari.ailus@iki.fi>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * version 2 as published by the Free Software Foundation.
13 *
14 * This program is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
22 * 02110-1301 USA
23 */
24
25#include <linux/bitops.h>
26#include <linux/slab.h>
27#include <linux/export.h>
28#include <media/v4l2-dev.h>
29#include <media/v4l2-fh.h>
30#include <media/v4l2-event.h>
31#include <media/v4l2-ioctl.h>
32
33void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev)
34{
35	fh->vdev = vdev;
36	/* Inherit from video_device. May be overridden by the driver. */
37	fh->ctrl_handler = vdev->ctrl_handler;
38	INIT_LIST_HEAD(&fh->list);
39	set_bit(V4L2_FL_USES_V4L2_FH, &fh->vdev->flags);
40	/*
41	 * determine_valid_ioctls() does not know if struct v4l2_fh
42	 * is used by this driver, but here we do. So enable the
43	 * prio ioctls here.
44	 */
45	set_bit(_IOC_NR(VIDIOC_G_PRIORITY), vdev->valid_ioctls);
46	set_bit(_IOC_NR(VIDIOC_S_PRIORITY), vdev->valid_ioctls);
47	fh->prio = V4L2_PRIORITY_UNSET;
48	init_waitqueue_head(&fh->wait);
49	INIT_LIST_HEAD(&fh->available);
50	INIT_LIST_HEAD(&fh->subscribed);
51	fh->sequence = -1;
52}
53EXPORT_SYMBOL_GPL(v4l2_fh_init);
54
55void v4l2_fh_add(struct v4l2_fh *fh)
56{
57	unsigned long flags;
58
59	v4l2_prio_open(fh->vdev->prio, &fh->prio);
60	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
61	list_add(&fh->list, &fh->vdev->fh_list);
62	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
63}
64EXPORT_SYMBOL_GPL(v4l2_fh_add);
65
66int v4l2_fh_open(struct file *filp)
67{
68	struct video_device *vdev = video_devdata(filp);
69	struct v4l2_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);
70
71	filp->private_data = fh;
72	if (fh == NULL)
73		return -ENOMEM;
74	v4l2_fh_init(fh, vdev);
75	v4l2_fh_add(fh);
76	return 0;
77}
78EXPORT_SYMBOL_GPL(v4l2_fh_open);
79
80void v4l2_fh_del(struct v4l2_fh *fh)
81{
82	unsigned long flags;
83
84	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
85	list_del_init(&fh->list);
86	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
87	v4l2_prio_close(fh->vdev->prio, fh->prio);
88}
89EXPORT_SYMBOL_GPL(v4l2_fh_del);
90
91void v4l2_fh_exit(struct v4l2_fh *fh)
92{
93	if (fh->vdev == NULL)
94		return;
95	v4l2_event_unsubscribe_all(fh);
96	fh->vdev = NULL;
97}
98EXPORT_SYMBOL_GPL(v4l2_fh_exit);
99
100int v4l2_fh_release(struct file *filp)
101{
102	struct v4l2_fh *fh = filp->private_data;
103
104	if (fh) {
105		v4l2_fh_del(fh);
106		v4l2_fh_exit(fh);
107		kfree(fh);
108	}
109	return 0;
110}
111EXPORT_SYMBOL_GPL(v4l2_fh_release);
112
113int v4l2_fh_is_singular(struct v4l2_fh *fh)
114{
115	unsigned long flags;
116	int is_singular;
117
118	if (fh == NULL || fh->vdev == NULL)
119		return 0;
120	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
121	is_singular = list_is_singular(&fh->list);
122	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
123	return is_singular;
124}
125EXPORT_SYMBOL_GPL(v4l2_fh_is_singular);
126