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