summaryrefslogtreecommitdiff
path: root/include/linux/hrtimer.h
blob: 306acf1dc6d58b54aef407d2ab9e370ff18eaa99 (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
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
/*
 *  include/linux/hrtimer.h
 *
 *  hrtimers - High-resolution kernel timers
 *
 *   Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
 *   Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
 *
 *  data type definitions, declarations, prototypes
 *
 *  Started by: Thomas Gleixner and Ingo Molnar
 *
 *  For licencing details see kernel-base/COPYING
 */
#ifndef _LINUX_HRTIMER_H
#define _LINUX_HRTIMER_H

#include <linux/rbtree.h>
#include <linux/ktime.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/wait.h>

/*
 * Mode arguments of xxx_hrtimer functions:
 */
enum hrtimer_mode {
	HRTIMER_ABS,	/* Time value is absolute */
	HRTIMER_REL,	/* Time value is relative to now */
};

enum hrtimer_restart {
	HRTIMER_NORESTART,
	HRTIMER_RESTART,
};

#define HRTIMER_INACTIVE	((void *)1UL)

struct hrtimer_base;

/**
 * struct hrtimer - the basic hrtimer structure
 *
 * @node:	red black tree node for time ordered insertion
 * @expires:	the absolute expiry time in the hrtimers internal
 *		representation. The time is related to the clock on
 *		which the timer is based.
 * @function:	timer expiry callback function
 * @base:	pointer to the timer base (per cpu and per clock)
 *
 * The hrtimer structure must be initialized by init_hrtimer_#CLOCKTYPE()
 */
struct hrtimer {
	struct rb_node		node;
	ktime_t			expires;
	int			(*function)(struct hrtimer *);
	struct hrtimer_base	*base;
};

/**
 * struct hrtimer_sleeper - simple sleeper structure
 *
 * @timer:	embedded timer structure
 * @task:	task to wake up
 *
 * task is set to NULL, when the timer expires.
 */
struct hrtimer_sleeper {
	struct hrtimer timer;
	struct task_struct *task;
};

/**
 * struct hrtimer_base - the timer base for a specific clock
 *
 * @index:		clock type index for per_cpu support when moving a timer
 *			to a base on another cpu.
 * @lock:		lock protecting the base and associated timers
 * @active:		red black tree root node for the active timers
 * @first:		pointer to the timer node which expires first
 * @resolution:		the resolution of the clock, in nanoseconds
 * @get_time:		function to retrieve the current time of the clock
 * @get_softirq_time:	function to retrieve the current time from the softirq
 * @curr_timer:		the timer which is executing a callback right now
 * @softirq_time:	the time when running the hrtimer queue in the softirq
 */
struct hrtimer_base {
	clockid_t		index;
	spinlock_t		lock;
	struct rb_root		active;
	struct rb_node		*first;
	ktime_t			resolution;
	ktime_t			(*get_time)(void);
	ktime_t			(*get_softirq_time)(void);
	struct hrtimer		*curr_timer;
	ktime_t			softirq_time;
};

/*
 * clock_was_set() is a NOP for non- high-resolution systems. The
 * time-sorted order guarantees that a timer does not expire early and
 * is expired in the next softirq when the clock was advanced.
 */
#define clock_was_set()		do { } while (0)

/* Exported timer functions: */

/* Initialize timers: */
extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
			 enum hrtimer_mode mode);

/* Basic timer operations: */
extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
			 const enum hrtimer_mode mode);
extern int hrtimer_cancel(struct hrtimer *timer);
extern int hrtimer_try_to_cancel(struct hrtimer *timer);

#define hrtimer_restart(timer) hrtimer_start((timer), (timer)->expires, HRTIMER_ABS)

/* Query timers: */
extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);
extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);

#ifdef CONFIG_NO_IDLE_HZ
extern ktime_t hrtimer_get_next_event(void);
#endif

static inline int hrtimer_active(const struct hrtimer *timer)
{
	return timer->node.rb_parent != HRTIMER_INACTIVE;
}

/* Forward a hrtimer so it expires after now: */
extern unsigned long
hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);

/* Precise sleep: */
extern long hrtimer_nanosleep(struct timespec *rqtp,
			      struct timespec __user *rmtp,
			      const enum hrtimer_mode mode,
			      const clockid_t clockid);

extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
				 struct task_struct *tsk);

/* Soft interrupt function to run the hrtimer queues: */
extern void hrtimer_run_queues(void);

/* Bootup initialization: */
extern void __init hrtimers_init(void);

#endif