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_PENDING, /* Timer is pending */ 44 }; 45 46 struct hrtimer_base; 47 48 /** 49 * struct hrtimer - the basic hrtimer structure 50 * 51 * @node: red black tree node for time ordered insertion 52 * @list: list head for easier access to the time ordered list, 53 * without walking the red black tree. 54 * @expires: the absolute expiry time in the hrtimers internal 55 * representation. The time is related to the clock on 56 * which the timer is based. 57 * @state: state of the timer 58 * @function: timer expiry callback function 59 * @data: argument for the callback function 60 * @base: pointer to the timer base (per cpu and per clock) 61 * 62 * The hrtimer structure must be initialized by init_hrtimer_#CLOCKTYPE() 63 */ 64 struct hrtimer { 65 struct rb_node node; 66 struct list_head list; 67 ktime_t expires; 68 enum hrtimer_state state; 69 int (*function)(void *); 70 void *data; 71 struct hrtimer_base *base; 72 }; 73 74 /** 75 * struct hrtimer_base - the timer base for a specific clock 76 * 77 * @index: clock type index for per_cpu support when moving a timer 78 * to a base on another cpu. 79 * @lock: lock protecting the base and associated timers 80 * @active: red black tree root node for the active timers 81 * @pending: list of pending timers for simple time ordered access 82 * @resolution: the resolution of the clock, in nanoseconds 83 * @get_time: function to retrieve the current time of the clock 84 * @curr_timer: the timer which is executing a callback right now 85 */ 86 struct hrtimer_base { 87 clockid_t index; 88 spinlock_t lock; 89 struct rb_root active; 90 struct list_head pending; 91 unsigned long resolution; 92 ktime_t (*get_time)(void); 93 struct hrtimer *curr_timer; 94 }; 95 96 /* 97 * clock_was_set() is a NOP for non- high-resolution systems. The 98 * time-sorted order guarantees that a timer does not expire early and 99 * is expired in the next softirq when the clock was advanced. 100 */ 101 #define clock_was_set() do { } while (0) 102 103 /* Exported timer functions: */ 104 105 /* Initialize timers: */ 106 extern void hrtimer_init(struct hrtimer *timer, const clockid_t which_clock); 107 extern void hrtimer_rebase(struct hrtimer *timer, const clockid_t which_clock); 108 109 110 /* Basic timer operations: */ 111 extern int hrtimer_start(struct hrtimer *timer, ktime_t tim, 112 const enum hrtimer_mode mode); 113 extern int hrtimer_cancel(struct hrtimer *timer); 114 extern int hrtimer_try_to_cancel(struct hrtimer *timer); 115 116 #define hrtimer_restart(timer) hrtimer_start((timer), (timer)->expires, HRTIMER_ABS) 117 118 /* Query timers: */ 119 extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer); 120 extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp); 121 122 static inline int hrtimer_active(const struct hrtimer *timer) 123 { 124 return timer->state == HRTIMER_PENDING; 125 } 126 127 /* Forward a hrtimer so it expires after now: */ 128 extern unsigned long hrtimer_forward(struct hrtimer *timer, 129 const 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