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1/*
2 * include/linux/hrtimer.h
3 *
4 * hrtimers - High-resolution kernel timers
5 *
6 * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
7 * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
8 *
9 * data type definitions, declarations, prototypes
10 *
11 * Started by: Thomas Gleixner and Ingo Molnar
12 *
13 * For licencing details see kernel-base/COPYING
14 */
15#ifndef _LINUX_HRTIMER_H
16#define _LINUX_HRTIMER_H
17
18#include <linux/rbtree.h>
19#include <linux/ktime.h>
20#include <linux/init.h>
21#include <linux/list.h>
22#include <linux/wait.h>
23
24/*
25 * Mode arguments of xxx_hrtimer functions:
26 */
27enum hrtimer_mode {
28 HRTIMER_ABS, /* Time value is absolute */
29 HRTIMER_REL, /* Time value is relative to now */
30};
31
32enum hrtimer_restart {
33 HRTIMER_NORESTART,
34 HRTIMER_RESTART,
35};
36
37/*
38 * Timer states:
39 */
40enum hrtimer_state {
41 HRTIMER_INACTIVE, /* Timer is inactive */
42 HRTIMER_EXPIRED, /* Timer is expired */
43 HRTIMER_RUNNING, /* Timer is running the callback function */
44 HRTIMER_PENDING, /* Timer is pending */
45};
46
47struct hrtimer_base;
48
49/**
50 * struct hrtimer - the basic hrtimer structure
51 *
52 * @node: red black tree node for time ordered insertion
53 * @expires: the absolute expiry time in the hrtimers internal
54 * representation. The time is related to the clock on
55 * which the timer is based.
56 * @state: state of the timer
57 * @function: timer expiry callback function
58 * @data: argument for the callback function
59 * @base: pointer to the timer base (per cpu and per clock)
60 *
61 * The hrtimer structure must be initialized by init_hrtimer_#CLOCKTYPE()
62 */
63struct hrtimer {
64 struct rb_node node;
65 ktime_t expires;
66 enum hrtimer_state state;
67 int (*function)(void *);
68 void *data;
69 struct hrtimer_base *base;
70};
71
72/**
73 * struct hrtimer_base - the timer base for a specific clock
74 *
75 * @index: clock type index for per_cpu support when moving a timer
76 * to a base on another cpu.
77 * @lock: lock protecting the base and associated timers
78 * @active: red black tree root node for the active timers
79 * @first: pointer to the timer node which expires first
80 * @resolution: the resolution of the clock, in nanoseconds
81 * @get_time: function to retrieve the current time of the clock
82 * @curr_timer: the timer which is executing a callback right now
83 */
84struct hrtimer_base {
85 clockid_t index;
86 spinlock_t lock;
87 struct rb_root active;
88 struct rb_node *first;
89 ktime_t resolution;
90 ktime_t (*get_time)(void);
91 struct hrtimer *curr_timer;
92};
93
94/*
95 * clock_was_set() is a NOP for non- high-resolution systems. The
96 * time-sorted order guarantees that a timer does not expire early and
97 * is expired in the next softirq when the clock was advanced.
98 */
99#define clock_was_set() do { } while (0)
100
101/* Exported timer functions: */
102
103/* Initialize timers: */
104extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
105 enum hrtimer_mode mode);
106
107/* Basic timer operations: */
108extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
109 const enum hrtimer_mode mode);
110extern int hrtimer_cancel(struct hrtimer *timer);
111extern int hrtimer_try_to_cancel(struct hrtimer *timer);
112
113#define hrtimer_restart(timer) hrtimer_start((timer), (timer)->expires, HRTIMER_ABS)
114
115/* Query timers: */
116extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);
117extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);
118
119#ifdef CONFIG_NO_IDLE_HZ
120extern ktime_t hrtimer_get_next_event(void);
121#endif
122
123static inline int hrtimer_active(const struct hrtimer *timer)
124{
125 return timer->state == HRTIMER_PENDING;
126}
127
128/* Forward a hrtimer so it expires after now: */
129extern unsigned long hrtimer_forward(struct hrtimer *timer, ktime_t interval);
130
131/* Precise sleep: */
132extern long hrtimer_nanosleep(struct timespec *rqtp,
133 struct timespec __user *rmtp,
134 const enum hrtimer_mode mode,
135 const clockid_t clockid);
136
137/* Soft interrupt function to run the hrtimer queues: */
138extern void hrtimer_run_queues(void);
139
140/* Bootup initialization: */
141extern void __init hrtimers_init(void);
142
143#endif