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_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 */ 74 struct 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: */ 96 extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock, 97 enum hrtimer_mode mode); 98 99 /* Basic timer operations: */ 100 extern int hrtimer_start(struct hrtimer *timer, ktime_t tim, 101 const enum hrtimer_mode mode); 102 extern int hrtimer_cancel(struct hrtimer *timer); 103 extern 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: */ 108 extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer); 109 extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp); 110 111 #ifdef CONFIG_NO_IDLE_HZ 112 extern ktime_t hrtimer_get_next_event(void); 113 #endif 114 115 static 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: */ 121 extern unsigned long 122 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval); 123 124 /* Precise sleep: */ 125 extern 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: */ 131 extern void hrtimer_run_queues(void); 132 133 /* Bootup initialization: */ 134 extern void __init hrtimers_init(void); 135 136 #endif 137