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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#define HRTIMER_INACTIVE ((void *)1UL)
38
39struct hrtimer_base;
40
41/**
42 * struct hrtimer - the basic hrtimer structure
43 *
44 * @node: red black tree node for time ordered insertion
45 * @expires: the absolute expiry time in the hrtimers internal
46 * representation. The time is related to the clock on
47 * which the timer is based.
48 * @function: timer expiry callback function
49 * @base: pointer to the timer base (per cpu and per clock)
50 *
51 * The hrtimer structure must be initialized by init_hrtimer_#CLOCKTYPE()
52 */
53struct hrtimer {
54 struct rb_node node;
55 ktime_t expires;
56 int (*function)(struct hrtimer *);
57 struct hrtimer_base *base;
58};
59
60/**
61 * struct hrtimer_sleeper - simple sleeper structure
62 *
63 * @timer: embedded timer structure
64 * @task: task to wake up
65 *
66 * task is set to NULL, when the timer expires.
67 */
68struct hrtimer_sleeper {
69 struct hrtimer timer;
70 struct task_struct *task;
71};
72
73/**
74 * struct hrtimer_base - the timer base for a specific clock
75 *
76 * @index: clock type index for per_cpu support when moving a timer
77 * to a base on another cpu.
78 * @lock: lock protecting the base and associated timers
79 * @active: red black tree root node for the active timers
80 * @first: pointer to the timer node which expires first
81 * @resolution: the resolution of the clock, in nanoseconds
82 * @get_time: function to retrieve the current time of the clock
83 * @get_softirq_time: function to retrieve the current time from the softirq
84 * @curr_timer: the timer which is executing a callback right now
85 * @softirq_time: the time when running the hrtimer queue in the softirq
86 */
87struct hrtimer_base {
88 clockid_t index;
89 spinlock_t lock;
90 struct rb_root active;
91 struct rb_node *first;
92 ktime_t resolution;
93 ktime_t (*get_time)(void);
94 ktime_t (*get_softirq_time)(void);
95 struct hrtimer *curr_timer;
96 ktime_t softirq_time;
97};
98
99/*
100 * clock_was_set() is a NOP for non- high-resolution systems. The
101 * time-sorted order guarantees that a timer does not expire early and
102 * is expired in the next softirq when the clock was advanced.
103 */
104#define clock_was_set() do { } while (0)
105
106/* Exported timer functions: */
107
108/* Initialize timers: */
109extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
110 enum hrtimer_mode mode);
111
112/* Basic timer operations: */
113extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
114 const enum hrtimer_mode mode);
115extern int hrtimer_cancel(struct hrtimer *timer);
116extern int hrtimer_try_to_cancel(struct hrtimer *timer);
117
118#define hrtimer_restart(timer) hrtimer_start((timer), (timer)->expires, HRTIMER_ABS)
119
120/* Query timers: */
121extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);
122extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);
123
124#ifdef CONFIG_NO_IDLE_HZ
125extern ktime_t hrtimer_get_next_event(void);
126#endif
127
128static inline int hrtimer_active(const struct hrtimer *timer)
129{
130 return timer->node.rb_parent != HRTIMER_INACTIVE;
131}
132
133/* Forward a hrtimer so it expires after now: */
134extern unsigned long
135hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
136
137/* Precise sleep: */
138extern long hrtimer_nanosleep(struct timespec *rqtp,
139 struct timespec __user *rmtp,
140 const enum hrtimer_mode mode,
141 const clockid_t clockid);
142
143extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
144 struct task_struct *tsk);
145
146/* Soft interrupt function to run the hrtimer queues: */
147extern void hrtimer_run_queues(void);
148
149/* Bootup initialization: */
150extern void __init hrtimers_init(void);
151
152#endif