cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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v4l2-fh.h (4317B)

      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 */