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 /* 38 * Timer states: 39 */ 40 enum hrtimer_state { 41 HRTIMER_INACTIVE, /* Timer is inactive */ 42 HRTIMER_EXPIRED, /* Timer is expired */ 43 HRTIMER_RUNNING, /* Timer is running the callback function */ 44 HRTIMER_PENDING, /* Timer is pending */ 45 }; 46 47 struct hrtimer_base; 48 49 /** 50 * struct hrtimer - the basic hrtimer structure 51 * 52 * @node: red black tree node for time ordered insertion 53 * @expires: the absolute expiry time in the hrtimers internal 54 * representation. The time is related to the clock on 55 * which the timer is based. 56 * @state: state of the timer 57 * @function: timer expiry callback function 58 * @data: argument for the callback function 59 * @base: pointer to the timer base (per cpu and per clock) 60 * 61 * The hrtimer structure must be initialized by init_hrtimer_#CLOCKTYPE() 62 */ 63 struct hrtimer { 64 struct rb_node node; 65 ktime_t expires; 66 enum hrtimer_state state; 67 int (*function)(void *); 68 void *data; 69 struct hrtimer_base *base; 70 }; 71 72 /** 73 * struct hrtimer_base - the timer base for a specific clock 74 * 75 * @index: clock type index for per_cpu support when moving a timer 76 * to a base on another cpu. 77 * @lock: lock protecting the base and associated timers 78 * @active: red black tree root node for the active timers 79 * @first: pointer to the timer node which expires first 80 * @resolution: the resolution of the clock, in nanoseconds 81 * @get_time: function to retrieve the current time of the clock 82 * @curr_timer: the timer which is executing a callback right now 83 */ 84 struct 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 struct hrtimer *curr_timer; 92 }; 93 94 /* 95 * clock_was_set() is a NOP for non- high-resolution systems. The 96 * time-sorted order guarantees that a timer does not expire early and 97 * is expired in the next softirq when the clock was advanced. 98 */ 99 #define clock_was_set() do { } while (0) 100 101 /* Exported timer functions: */ 102 103 /* Initialize timers: */ 104 extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock, 105 enum hrtimer_mode mode); 106 107 /* Basic timer operations: */ 108 extern int hrtimer_start(struct hrtimer *timer, ktime_t tim, 109 const enum hrtimer_mode mode); 110 extern int hrtimer_cancel(struct hrtimer *timer); 111 extern int hrtimer_try_to_cancel(struct hrtimer *timer); 112 113 #define hrtimer_restart(timer) hrtimer_start((timer), (timer)->expires, HRTIMER_ABS) 114 115 /* Query timers: */ 116 extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer); 117 extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp); 118 119 #ifdef CONFIG_NO_IDLE_HZ 120 extern ktime_t hrtimer_get_next_event(void); 121 #endif 122 123 static inline int hrtimer_active(const struct hrtimer *timer) 124 { 125 return timer->state == HRTIMER_PENDING; 126 } 127 128 /* Forward a hrtimer so it expires after now: */ 129 extern unsigned long hrtimer_forward(struct hrtimer *timer, ktime_t interval); 130 131 /* Precise sleep: */ 132 extern long hrtimer_nanosleep(struct timespec *rqtp, 133 struct timespec __user *rmtp, 134 const enum hrtimer_mode mode, 135 const clockid_t clockid); 136 137 /* Soft interrupt function to run the hrtimer queues: */ 138 extern void hrtimer_run_queues(void); 139 140 /* Bootup initialization: */ 141 extern void __init hrtimers_init(void); 142 143 #endif 144