1/*  linux/include/linux/tick.h
2 *
3 *  This file contains the structure definitions for tick related functions
4 *
5 */
6#ifndef _LINUX_TICK_H
7#define _LINUX_TICK_H
8
9#include <linux/clockchips.h>
10#include <linux/irqflags.h>
11
12#ifdef CONFIG_GENERIC_CLOCKEVENTS
13
14enum tick_device_mode {
15	TICKDEV_MODE_PERIODIC,
16	TICKDEV_MODE_ONESHOT,
17};
18
19struct tick_device {
20	struct clock_event_device *evtdev;
21	enum tick_device_mode mode;
22};
23
24enum tick_nohz_mode {
25	NOHZ_MODE_INACTIVE,
26	NOHZ_MODE_LOWRES,
27	NOHZ_MODE_HIGHRES,
28};
29
30/**
31 * struct tick_sched - sched tick emulation and no idle tick control/stats
32 * @sched_timer:	hrtimer to schedule the periodic tick in high
33 *			resolution mode
34 * @idle_tick:		Store the last idle tick expiry time when the tick
35 *			timer is modified for idle sleeps. This is necessary
36 *			to resume the tick timer operation in the timeline
37 *			when the CPU returns from idle
38 * @tick_stopped:	Indicator that the idle tick has been stopped
39 * @idle_jiffies:	jiffies at the entry to idle for idle time accounting
40 * @idle_calls:		Total number of idle calls
41 * @idle_sleeps:	Number of idle calls, where the sched tick was stopped
42 * @idle_entrytime:	Time when the idle call was entered
43 * @idle_waketime:	Time when the idle was interrupted
44 * @idle_exittime:	Time when the idle state was left
45 * @idle_sleeptime:	Sum of the time slept in idle with sched tick stopped
46 * @iowait_sleeptime:	Sum of the time slept in idle with sched tick stopped, with IO outstanding
47 * @sleep_length:	Duration of the current idle sleep
48 * @do_timer_lst:	CPU was the last one doing do_timer before going idle
49 */
50struct tick_sched {
51	struct hrtimer			sched_timer;
52	unsigned long			check_clocks;
53	enum tick_nohz_mode		nohz_mode;
54	ktime_t				idle_tick;
55	int				inidle;
56	int				tick_stopped;
57	unsigned long			idle_jiffies;
58	unsigned long			idle_calls;
59	unsigned long			idle_sleeps;
60	int				idle_active;
61	ktime_t				idle_entrytime;
62	ktime_t				idle_waketime;
63	ktime_t				idle_exittime;
64	ktime_t				idle_sleeptime;
65	ktime_t				iowait_sleeptime;
66	ktime_t				sleep_length;
67	unsigned long			last_jiffies;
68	unsigned long			next_jiffies;
69	ktime_t				idle_expires;
70	int				do_timer_last;
71};
72
73extern void __init tick_init(void);
74extern int tick_is_oneshot_available(void);
75extern struct tick_device *tick_get_device(int cpu);
76
77# ifdef CONFIG_HIGH_RES_TIMERS
78extern int tick_init_highres(void);
79extern int tick_program_event(ktime_t expires, int force);
80extern void tick_setup_sched_timer(void);
81# endif
82
83# if defined CONFIG_NO_HZ || defined CONFIG_HIGH_RES_TIMERS
84extern void tick_cancel_sched_timer(int cpu);
85# else
86static inline void tick_cancel_sched_timer(int cpu) { }
87# endif
88
89# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
90extern struct tick_device *tick_get_broadcast_device(void);
91extern struct cpumask *tick_get_broadcast_mask(void);
92
93#  ifdef CONFIG_TICK_ONESHOT
94extern struct cpumask *tick_get_broadcast_oneshot_mask(void);
95#  endif
96
97# endif /* BROADCAST */
98
99# ifdef CONFIG_TICK_ONESHOT
100extern void tick_clock_notify(void);
101extern int tick_check_oneshot_change(int allow_nohz);
102extern struct tick_sched *tick_get_tick_sched(int cpu);
103extern void tick_check_idle(int cpu);
104extern int tick_oneshot_mode_active(void);
105#  ifndef arch_needs_cpu
106#   define arch_needs_cpu(cpu) (0)
107#  endif
108# else
109static inline void tick_clock_notify(void) { }
110static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
111static inline void tick_check_idle(int cpu) { }
112static inline int tick_oneshot_mode_active(void) { return 0; }
113# endif
114
115#else /* CONFIG_GENERIC_CLOCKEVENTS */
116static inline void tick_init(void) { }
117static inline void tick_cancel_sched_timer(int cpu) { }
118static inline void tick_clock_notify(void) { }
119static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
120static inline void tick_check_idle(int cpu) { }
121static inline int tick_oneshot_mode_active(void) { return 0; }
122#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
123
124# ifdef CONFIG_NO_HZ
125extern void tick_nohz_idle_enter(void);
126extern void tick_nohz_idle_exit(void);
127extern void tick_nohz_irq_exit(void);
128extern ktime_t tick_nohz_get_sleep_length(void);
129extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
130extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
131# else
132static inline void tick_nohz_idle_enter(void) { }
133static inline void tick_nohz_idle_exit(void) { }
134
135static inline ktime_t tick_nohz_get_sleep_length(void)
136{
137	ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
138
139	return len;
140}
141static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
142static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
143# endif /* !NO_HZ */
144
145#endif
146