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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * v4l2-fh.h
4 *
5 * V4L2 file handle. Store per file handle data for the V4L2
6 * framework. Using file handles is optional for the drivers.
7 *
8 * Copyright (C) 2009--2010 Nokia Corporation.
9 *
10 * Contact: Sakari Ailus <sakari.ailus@iki.fi>
11 */
12
13#ifndef V4L2_FH_H
14#define V4L2_FH_H
15
16#include <linux/fs.h>
17#include <linux/kconfig.h>
18#include <linux/list.h>
19#include <linux/videodev2.h>
20
21struct video_device;
22struct v4l2_ctrl_handler;
23
24/**
25 * struct v4l2_fh - Describes a V4L2 file handler
26 *
27 * @list: list of file handlers
28 * @vdev: pointer to &struct video_device
29 * @ctrl_handler: pointer to &struct v4l2_ctrl_handler
30 * @prio: priority of the file handler, as defined by &enum v4l2_priority
31 *
32 * @wait: event' s wait queue
33 * @subscribe_lock: serialise changes to the subscribed list; guarantee that
34 * the add and del event callbacks are orderly called
35 * @subscribed: list of subscribed events
36 * @available: list of events waiting to be dequeued
37 * @navailable: number of available events at @available list
38 * @sequence: event sequence number
39 *
40 * @m2m_ctx: pointer to &struct v4l2_m2m_ctx
41 */
42struct v4l2_fh {
43 struct list_head list;
44 struct video_device *vdev;
45 struct v4l2_ctrl_handler *ctrl_handler;
46 enum v4l2_priority prio;
47
48 /* Events */
49 wait_queue_head_t wait;
50 struct mutex subscribe_lock;
51 struct list_head subscribed;
52 struct list_head available;
53 unsigned int navailable;
54 u32 sequence;
55
56 struct v4l2_m2m_ctx *m2m_ctx;
57};
58
59/**
60 * v4l2_fh_init - Initialise the file handle.
61 *
62 * @fh: pointer to &struct v4l2_fh
63 * @vdev: pointer to &struct video_device
64 *
65 * Parts of the V4L2 framework using the
66 * file handles should be initialised in this function. Must be called
67 * from driver's v4l2_file_operations->open\(\) handler if the driver
68 * uses &struct v4l2_fh.
69 */
70void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev);
71
72/**
73 * v4l2_fh_add - Add the fh to the list of file handles on a video_device.
74 *
75 * @fh: pointer to &struct v4l2_fh
76 *
77 * .. note::
78 * The @fh file handle must be initialised first.
79 */
80void v4l2_fh_add(struct v4l2_fh *fh);
81
82/**
83 * v4l2_fh_open - Ancillary routine that can be used as the open\(\) op
84 * of v4l2_file_operations.
85 *
86 * @filp: pointer to struct file
87 *
88 * It allocates a v4l2_fh and inits and adds it to the &struct video_device
89 * associated with the file pointer.
90 */
91int v4l2_fh_open(struct file *filp);
92
93/**
94 * v4l2_fh_del - Remove file handle from the list of file handles.
95 *
96 * @fh: pointer to &struct v4l2_fh
97 *
98 * On error filp->private_data will be %NULL, otherwise it will point to
99 * the &struct v4l2_fh.
100 *
101 * .. note::
102 * Must be called in v4l2_file_operations->release\(\) handler if the driver
103 * uses &struct v4l2_fh.
104 */
105void v4l2_fh_del(struct v4l2_fh *fh);
106
107/**
108 * v4l2_fh_exit - Release resources related to a file handle.
109 *
110 * @fh: pointer to &struct v4l2_fh
111 *
112 * Parts of the V4L2 framework using the v4l2_fh must release their
113 * resources here, too.
114 *
115 * .. note::
116 * Must be called in v4l2_file_operations->release\(\) handler if the
117 * driver uses &struct v4l2_fh.
118 */
119void v4l2_fh_exit(struct v4l2_fh *fh);
120
121/**
122 * v4l2_fh_release - Ancillary routine that can be used as the release\(\) op
123 * of v4l2_file_operations.
124 *
125 * @filp: pointer to struct file
126 *
127 * It deletes and exits the v4l2_fh associated with the file pointer and
128 * frees it. It will do nothing if filp->private_data (the pointer to the
129 * v4l2_fh struct) is %NULL.
130 *
131 * This function always returns 0.
132 */
133int v4l2_fh_release(struct file *filp);
134
135/**
136 * v4l2_fh_is_singular - Returns 1 if this filehandle is the only filehandle
137 * opened for the associated video_device.
138 *
139 * @fh: pointer to &struct v4l2_fh
140 *
141 * If @fh is NULL, then it returns 0.
142 */
143int v4l2_fh_is_singular(struct v4l2_fh *fh);
144
145/**
146 * v4l2_fh_is_singular_file - Returns 1 if this filehandle is the only
147 * filehandle opened for the associated video_device.
148 *
149 * @filp: pointer to struct file
150 *
151 * This is a helper function variant of v4l2_fh_is_singular() with uses
152 * struct file as argument.
153 *
154 * If filp->private_data is %NULL, then it will return 0.
155 */
156static inline int v4l2_fh_is_singular_file(struct file *filp)
157{
158 return v4l2_fh_is_singular(filp->private_data);
159}
160
161#endif /* V4L2_EVENT_H */
1/*
2 * v4l2-fh.h
3 *
4 * V4L2 file handle. Store per file handle data for the V4L2
5 * framework. Using file handles is optional for the drivers.
6 *
7 * Copyright (C) 2009--2010 Nokia Corporation.
8 *
9 * Contact: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com>
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * version 2 as published by the Free Software Foundation.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
23 * 02110-1301 USA
24 */
25
26#ifndef V4L2_FH_H
27#define V4L2_FH_H
28
29#include <linux/list.h>
30
31struct video_device;
32struct v4l2_ctrl_handler;
33
34struct v4l2_fh {
35 struct list_head list;
36 struct video_device *vdev;
37 struct v4l2_ctrl_handler *ctrl_handler;
38 enum v4l2_priority prio;
39
40 /* Events */
41 wait_queue_head_t wait;
42 struct list_head subscribed; /* Subscribed events */
43 struct list_head available; /* Dequeueable event */
44 unsigned int navailable;
45 u32 sequence;
46};
47
48/*
49 * Initialise the file handle. Parts of the V4L2 framework using the
50 * file handles should be initialised in this function. Must be called
51 * from driver's v4l2_file_operations->open() handler if the driver
52 * uses v4l2_fh.
53 */
54void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev);
55/*
56 * Add the fh to the list of file handles on a video_device. The file
57 * handle must be initialised first.
58 */
59void v4l2_fh_add(struct v4l2_fh *fh);
60/*
61 * Can be used as the open() op of v4l2_file_operations.
62 * It allocates a v4l2_fh and inits and adds it to the video_device associated
63 * with the file pointer.
64 */
65int v4l2_fh_open(struct file *filp);
66/*
67 * Remove file handle from the list of file handles. Must be called in
68 * v4l2_file_operations->release() handler if the driver uses v4l2_fh.
69 * On error filp->private_data will be NULL, otherwise it will point to
70 * the v4l2_fh struct.
71 */
72void v4l2_fh_del(struct v4l2_fh *fh);
73/*
74 * Release resources related to a file handle. Parts of the V4L2
75 * framework using the v4l2_fh must release their resources here, too.
76 * Must be called in v4l2_file_operations->release() handler if the
77 * driver uses v4l2_fh.
78 */
79void v4l2_fh_exit(struct v4l2_fh *fh);
80/*
81 * Can be used as the release() op of v4l2_file_operations.
82 * It deletes and exits the v4l2_fh associated with the file pointer and
83 * frees it. It will do nothing if filp->private_data (the pointer to the
84 * v4l2_fh struct) is NULL. This function always returns 0.
85 */
86int v4l2_fh_release(struct file *filp);
87/*
88 * Returns 1 if this filehandle is the only filehandle opened for the
89 * associated video_device. If fh is NULL, then it returns 0.
90 */
91int v4l2_fh_is_singular(struct v4l2_fh *fh);
92/*
93 * Helper function with struct file as argument. If filp->private_data is
94 * NULL, then it will return 0.
95 */
96static inline int v4l2_fh_is_singular_file(struct file *filp)
97{
98 return v4l2_fh_is_singular(filp->private_data);
99}
100
101#endif /* V4L2_EVENT_H */