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Thomas Gleixnerc0a31322006-01-09 20:52:32 -08001/*
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
Thomas Gleixner3c8aa392007-02-16 01:27:50 -080024struct hrtimer_clock_base;
25struct hrtimer_cpu_base;
26
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080027/*
28 * Mode arguments of xxx_hrtimer functions:
29 */
30enum hrtimer_mode {
Thomas Gleixnerc9cb2e32007-02-16 01:27:49 -080031 HRTIMER_MODE_ABS, /* Time value is absolute */
32 HRTIMER_MODE_REL, /* Time value is relative to now */
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080033};
34
Thomas Gleixnerc9cb2e32007-02-16 01:27:49 -080035/*
36 * Return values for the callback function
37 */
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080038enum hrtimer_restart {
Thomas Gleixnerc9cb2e32007-02-16 01:27:49 -080039 HRTIMER_NORESTART, /* Timer is not restarted */
40 HRTIMER_RESTART, /* Timer must be restarted */
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080041};
42
Thomas Gleixner303e9672007-02-16 01:27:51 -080043/*
44 * Bit values to track state of the timer
45 *
46 * Possible states:
47 *
48 * 0x00 inactive
49 * 0x01 enqueued into rbtree
50 * 0x02 callback function running
51 * 0x03 callback function running and enqueued
52 * (was requeued on another CPU)
53 *
54 * The "callback function running and enqueued" status is only possible on
55 * SMP. It happens for example when a posix timer expired and the callback
56 * queued a signal. Between dropping the lock which protects the posix timer
57 * and reacquiring the base lock of the hrtimer, another CPU can deliver the
58 * signal and rearm the timer. We have to preserve the callback running state,
59 * as otherwise the timer could be removed before the softirq code finishes the
60 * the handling of the timer.
61 *
62 * The HRTIMER_STATE_ENQUEUE bit is always or'ed to the current state to
63 * preserve the HRTIMER_STATE_CALLBACK bit in the above scenario.
64 *
65 * All state transitions are protected by cpu_base->lock.
66 */
67#define HRTIMER_STATE_INACTIVE 0x00
68#define HRTIMER_STATE_ENQUEUED 0x01
69#define HRTIMER_STATE_CALLBACK 0x02
70
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080071/**
72 * struct hrtimer - the basic hrtimer structure
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080073 * @node: red black tree node for time ordered insertion
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080074 * @expires: the absolute expiry time in the hrtimers internal
75 * representation. The time is related to the clock on
76 * which the timer is based.
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080077 * @function: timer expiry callback function
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080078 * @base: pointer to the timer base (per cpu and per clock)
Thomas Gleixner303e9672007-02-16 01:27:51 -080079 * @state: state information (See bit values above)
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080080 *
81 * The hrtimer structure must be initialized by init_hrtimer_#CLOCKTYPE()
82 */
83struct hrtimer {
Thomas Gleixner3c8aa392007-02-16 01:27:50 -080084 struct rb_node node;
85 ktime_t expires;
86 enum hrtimer_restart (*function)(struct hrtimer *);
87 struct hrtimer_clock_base *base;
Thomas Gleixner303e9672007-02-16 01:27:51 -080088 unsigned long state;
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080089};
90
91/**
Thomas Gleixner00362e32006-03-31 02:31:17 -080092 * struct hrtimer_sleeper - simple sleeper structure
Thomas Gleixner00362e32006-03-31 02:31:17 -080093 * @timer: embedded timer structure
94 * @task: task to wake up
95 *
96 * task is set to NULL, when the timer expires.
97 */
98struct hrtimer_sleeper {
99 struct hrtimer timer;
100 struct task_struct *task;
101};
102
103/**
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800104 * struct hrtimer_base - the timer base for a specific clock
Thomas Gleixner3c8aa392007-02-16 01:27:50 -0800105 * @index: clock type index for per_cpu support when moving a
106 * timer to a base on another cpu.
Thomas Gleixner92127c72006-03-26 01:38:05 -0800107 * @active: red black tree root node for the active timers
108 * @first: pointer to the timer node which expires first
109 * @resolution: the resolution of the clock, in nanoseconds
110 * @get_time: function to retrieve the current time of the clock
Martin Waitza5802902006-04-02 13:59:55 +0200111 * @get_softirq_time: function to retrieve the current time from the softirq
Thomas Gleixner92127c72006-03-26 01:38:05 -0800112 * @softirq_time: the time when running the hrtimer queue in the softirq
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800113 */
Thomas Gleixner3c8aa392007-02-16 01:27:50 -0800114struct hrtimer_clock_base {
115 struct hrtimer_cpu_base *cpu_base;
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800116 clockid_t index;
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800117 struct rb_root active;
Thomas Gleixner288867e2006-01-12 11:25:54 +0100118 struct rb_node *first;
Thomas Gleixnere2787632006-01-12 11:36:14 +0100119 ktime_t resolution;
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800120 ktime_t (*get_time)(void);
Thomas Gleixner92127c72006-03-26 01:38:05 -0800121 ktime_t (*get_softirq_time)(void);
Thomas Gleixner92127c72006-03-26 01:38:05 -0800122 ktime_t softirq_time;
Thomas Gleixner3c8aa392007-02-16 01:27:50 -0800123};
124
125#define HRTIMER_MAX_CLOCK_BASES 2
126
127/*
128 * struct hrtimer_cpu_base - the per cpu clock bases
129 * @lock: lock protecting the base and associated clock bases
130 * and timers
131 * @lock_key: the lock_class_key for use with lockdep
132 * @clock_base: array of clock bases for this cpu
133 * @curr_timer: the timer which is executing a callback right now
134 */
135struct hrtimer_cpu_base {
136 spinlock_t lock;
137 struct lock_class_key lock_key;
138 struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
139 struct hrtimer *curr_timer;
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800140};
141
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800142/*
143 * clock_was_set() is a NOP for non- high-resolution systems. The
144 * time-sorted order guarantees that a timer does not expire early and
145 * is expired in the next softirq when the clock was advanced.
146 */
147#define clock_was_set() do { } while (0)
148
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800149/* Exported timer functions: */
150
151/* Initialize timers: */
George Anzinger7978672c2006-02-01 03:05:11 -0800152extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
153 enum hrtimer_mode mode);
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800154
155/* Basic timer operations: */
156extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
157 const enum hrtimer_mode mode);
158extern int hrtimer_cancel(struct hrtimer *timer);
159extern int hrtimer_try_to_cancel(struct hrtimer *timer);
160
Thomas Gleixnerc9cb2e32007-02-16 01:27:49 -0800161static inline int hrtimer_restart(struct hrtimer *timer)
162{
163 return hrtimer_start(timer, timer->expires, HRTIMER_MODE_ABS);
164}
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800165
166/* Query timers: */
167extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);
168extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);
169
Tony Lindgren69239742006-03-06 15:42:45 -0800170#ifdef CONFIG_NO_IDLE_HZ
171extern ktime_t hrtimer_get_next_event(void);
172#endif
173
Thomas Gleixner303e9672007-02-16 01:27:51 -0800174/*
175 * A timer is active, when it is enqueued into the rbtree or the callback
176 * function is running.
177 */
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800178static inline int hrtimer_active(const struct hrtimer *timer)
179{
Thomas Gleixner303e9672007-02-16 01:27:51 -0800180 return timer->state != HRTIMER_STATE_INACTIVE;
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800181}
182
183/* Forward a hrtimer so it expires after now: */
Roman Zippel44f21472006-03-26 01:38:06 -0800184extern unsigned long
185hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800186
Thomas Gleixner10c94ec2006-01-09 20:52:35 -0800187/* Precise sleep: */
188extern long hrtimer_nanosleep(struct timespec *rqtp,
189 struct timespec __user *rmtp,
190 const enum hrtimer_mode mode,
191 const clockid_t clockid);
Toyo Abe1711ef32006-09-29 02:00:28 -0700192extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);
Thomas Gleixner10c94ec2006-01-09 20:52:35 -0800193
Thomas Gleixner00362e32006-03-31 02:31:17 -0800194extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
195 struct task_struct *tsk);
196
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800197/* Soft interrupt function to run the hrtimer queues: */
198extern void hrtimer_run_queues(void);
199
John Stultz411187f2007-02-16 01:27:30 -0800200/* Resume notification */
201void hrtimer_notify_resume(void);
202
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800203/* Bootup initialization: */
204extern void __init hrtimers_init(void);
205
206#endif