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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_base - the timer base for a specific clock
62 *
63 * @index: clock type index for per_cpu support when moving a timer
64 * to a base on another cpu.
65 * @lock: lock protecting the base and associated timers
66 * @active: red black tree root node for the active timers
67 * @first: pointer to the timer node which expires first
68 * @resolution: the resolution of the clock, in nanoseconds
69 * @get_time: function to retrieve the current time of the clock
70 * @get_sofirq_time: function to retrieve the current time from the softirq
71 * @curr_timer: the timer which is executing a callback right now
72 * @softirq_time: the time when running the hrtimer queue in the softirq
73 */
74struct hrtimer_base {
75 clockid_t index;
76 spinlock_t lock;
77 struct rb_root active;
78 struct rb_node *first;
79 ktime_t resolution;
80 ktime_t (*get_time)(void);
81 ktime_t (*get_softirq_time)(void);
82 struct hrtimer *curr_timer;
83 ktime_t softirq_time;
84};
85
86/*
87 * clock_was_set() is a NOP for non- high-resolution systems. The
88 * time-sorted order guarantees that a timer does not expire early and
89 * is expired in the next softirq when the clock was advanced.
90 */
91#define clock_was_set() do { } while (0)
92
93/* Exported timer functions: */
94
95/* Initialize timers: */
96extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
97 enum hrtimer_mode mode);
98
99/* Basic timer operations: */
100extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
101 const enum hrtimer_mode mode);
102extern int hrtimer_cancel(struct hrtimer *timer);
103extern int hrtimer_try_to_cancel(struct hrtimer *timer);
104
105#define hrtimer_restart(timer) hrtimer_start((timer), (timer)->expires, HRTIMER_ABS)
106
107/* Query timers: */
108extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);
109extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);
110
111#ifdef CONFIG_NO_IDLE_HZ
112extern ktime_t hrtimer_get_next_event(void);
113#endif
114
115static inline int hrtimer_active(const struct hrtimer *timer)
116{
117 return timer->node.rb_parent != HRTIMER_INACTIVE;
118}
119
120/* Forward a hrtimer so it expires after now: */
121extern unsigned long
122hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
123
124/* Precise sleep: */
125extern long hrtimer_nanosleep(struct timespec *rqtp,
126 struct timespec __user *rmtp,
127 const enum hrtimer_mode mode,
128 const clockid_t clockid);
129
130/* Soft interrupt function to run the hrtimer queues: */
131extern void hrtimer_run_queues(void);
132
133/* Bootup initialization: */
134extern void __init hrtimers_init(void);
135
136#endif