1 /* 2 * include/linux/hrtimer.h 3 * 4 * hrtimers - High-resolution kernel timers 5 * 6 * Copyright(C) 2005, Thomas Gleixner <[email protected]> 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 */ 27 enum hrtimer_mode { 28 HRTIMER_ABS, /* Time value is absolute */ 29 HRTIMER_REL, /* Time value is relative to now */ 30 }; 31 32 enum hrtimer_restart { 33 HRTIMER_NORESTART, 34 HRTIMER_RESTART, 35 }; 36 37 #define HRTIMER_INACTIVE ((void *)1UL) 38 39 struct 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 */ 52 struct 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 */ 66 struct 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 * @lock_key: the lock_class_key for use with lockdep 84 */ 85 struct hrtimer_base { 86 clockid_t index; 87 spinlock_t lock; 88 struct rb_root active; 89 struct rb_node *first; 90 ktime_t resolution; 91 ktime_t (*get_time)(void); 92 ktime_t (*get_softirq_time)(void); 93 struct hrtimer *curr_timer; 94 ktime_t softirq_time; 95 struct lock_class_key lock_key; 96 }; 97 98 /* 99 * clock_was_set() is a NOP for non- high-resolution systems. The 100 * time-sorted order guarantees that a timer does not expire early and 101 * is expired in the next softirq when the clock was advanced. 102 */ 103 #define clock_was_set() do { } while (0) 104 105 /* Exported timer functions: */ 106 107 /* Initialize timers: */ 108 extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock, 109 enum hrtimer_mode mode); 110 111 /* Basic timer operations: */ 112 extern int hrtimer_start(struct hrtimer *timer, ktime_t tim, 113 const enum hrtimer_mode mode); 114 extern int hrtimer_cancel(struct hrtimer *timer); 115 extern int hrtimer_try_to_cancel(struct hrtimer *timer); 116 117 #define hrtimer_restart(timer) hrtimer_start((timer), (timer)->expires, HRTIMER_ABS) 118 119 /* Query timers: */ 120 extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer); 121 extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp); 122 123 #ifdef CONFIG_NO_IDLE_HZ 124 extern ktime_t hrtimer_get_next_event(void); 125 #endif 126 127 static inline int hrtimer_active(const struct hrtimer *timer) 128 { 129 return rb_parent(&timer->node) != &timer->node; 130 } 131 132 /* Forward a hrtimer so it expires after now: */ 133 extern unsigned long 134 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval); 135 136 /* Precise sleep: */ 137 extern long hrtimer_nanosleep(struct timespec *rqtp, 138 struct timespec __user *rmtp, 139 const enum hrtimer_mode mode, 140 const clockid_t clockid); 141 142 extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, 143 struct task_struct *tsk); 144 145 /* Soft interrupt function to run the hrtimer queues: */ 146 extern void hrtimer_run_queues(void); 147 148 /* Bootup initialization: */ 149 extern void __init hrtimers_init(void); 150 151 #endif 152