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 * 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 */ 53 struct 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 */ 68 struct 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 */ 87 struct 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: */ 109 extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock, 110 enum hrtimer_mode mode); 111 112 /* Basic timer operations: */ 113 extern int hrtimer_start(struct hrtimer *timer, ktime_t tim, 114 const enum hrtimer_mode mode); 115 extern int hrtimer_cancel(struct hrtimer *timer); 116 extern 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: */ 121 extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer); 122 extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp); 123 124 #ifdef CONFIG_NO_IDLE_HZ 125 extern ktime_t hrtimer_get_next_event(void); 126 #endif 127 128 static 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: */ 134 extern unsigned long 135 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval); 136 137 /* Precise sleep: */ 138 extern long hrtimer_nanosleep(struct timespec *rqtp, 139 struct timespec __user *rmtp, 140 const enum hrtimer_mode mode, 141 const clockid_t clockid); 142 143 extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, 144 struct task_struct *tsk); 145 146 /* Soft interrupt function to run the hrtimer queues: */ 147 extern void hrtimer_run_queues(void); 148 149 /* Bootup initialization: */ 150 extern void __init hrtimers_init(void); 151 152 #endif 153