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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_PENDING, /* Timer is pending */
44};
45
46struct hrtimer_base;
47
48/**
49 * struct hrtimer - the basic hrtimer structure
50 *
51 * @node: red black tree node for time ordered insertion
52 * @list: list head for easier access to the time ordered list,
53 * without walking the red black tree.
54 * @expires: the absolute expiry time in the hrtimers internal
55 * representation. The time is related to the clock on
56 * which the timer is based.
57 * @state: state of the timer
58 * @function: timer expiry callback function
59 * @data: argument for the callback function
60 * @base: pointer to the timer base (per cpu and per clock)
61 *
62 * The hrtimer structure must be initialized by init_hrtimer_#CLOCKTYPE()
63 */
64struct hrtimer {
65 struct rb_node node;
66 struct list_head list;
67 ktime_t expires;
68 enum hrtimer_state state;
69 int (*function)(void *);
70 void *data;
71 struct hrtimer_base *base;
72};
73
74/**
75 * struct hrtimer_base - the timer base for a specific clock
76 *
77 * @index: clock type index for per_cpu support when moving a timer
78 * to a base on another cpu.
79 * @lock: lock protecting the base and associated timers
80 * @active: red black tree root node for the active timers
81 * @pending: list of pending timers for simple time ordered access
82 * @resolution: the resolution of the clock, in nanoseconds
83 * @get_time: function to retrieve the current time of the clock
84 * @curr_timer: the timer which is executing a callback right now
85 */
86struct hrtimer_base {
87 clockid_t index;
88 spinlock_t lock;
89 struct rb_root active;
90 struct list_head pending;
91 unsigned long resolution;
92 ktime_t (*get_time)(void);
93 struct hrtimer *curr_timer;
94};
95
96/*
97 * clock_was_set() is a NOP for non- high-resolution systems. The
98 * time-sorted order guarantees that a timer does not expire early and
99 * is expired in the next softirq when the clock was advanced.
100 */
101#define clock_was_set() do { } while (0)
102
103/* Exported timer functions: */
104
105/* Initialize timers: */
106extern void hrtimer_init(struct hrtimer *timer, const clockid_t which_clock);
107extern void hrtimer_rebase(struct hrtimer *timer, const clockid_t which_clock);
108
109
110/* Basic timer operations: */
111extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
112 const enum hrtimer_mode mode);
113extern int hrtimer_cancel(struct hrtimer *timer);
114extern int hrtimer_try_to_cancel(struct hrtimer *timer);
115
116#define hrtimer_restart(timer) hrtimer_start((timer), (timer)->expires, HRTIMER_ABS)
117
118/* Query timers: */
119extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);
120extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);
121
122static inline int hrtimer_active(const struct hrtimer *timer)
123{
124 return timer->state == HRTIMER_PENDING;
125}
126
127/* Forward a hrtimer so it expires after now: */
128extern unsigned long hrtimer_forward(struct hrtimer *timer,
129 const 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