1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _TICK_SCHED_H
  3#define _TICK_SCHED_H
  4
  5#include <linux/hrtimer.h>
  6
  7enum tick_device_mode {
  8	TICKDEV_MODE_PERIODIC,
  9	TICKDEV_MODE_ONESHOT,
 10};
 11
 12struct tick_device {
 13	struct clock_event_device *evtdev;
 14	enum tick_device_mode mode;
 15};
 16
 17/* The CPU is in the tick idle mode */
 18#define TS_FLAG_INIDLE		BIT(0)
 19/* The idle tick has been stopped */
 20#define TS_FLAG_STOPPED		BIT(1)
 21/*
 22 * Indicator that the CPU is actively in the tick idle mode;
 23 * it is reset during irq handling phases.
 24 */
 25#define TS_FLAG_IDLE_ACTIVE	BIT(2)
 26/* CPU was the last one doing do_timer before going idle */
 27#define TS_FLAG_DO_TIMER_LAST	BIT(3)
 28/* NO_HZ is enabled */
 29#define TS_FLAG_NOHZ		BIT(4)
 30/* High resolution tick mode */
 31#define TS_FLAG_HIGHRES		BIT(5)
 32
 33/**
 34 * struct tick_sched - sched tick emulation and no idle tick control/stats
 35 *
 36 * @flags:		State flags gathering the TS_FLAG_* features
 37 * @got_idle_tick:	Tick timer function has run with @inidle set
 38 * @stalled_jiffies:	Number of stalled jiffies detected across ticks
 39 * @last_tick_jiffies:	Value of jiffies seen on last tick
 40 * @sched_timer:	hrtimer to schedule the periodic tick in high
 41 *			resolution mode
 42 * @last_tick:		Store the last tick expiry time when the tick
 43 *			timer is modified for nohz sleeps. This is necessary
 44 *			to resume the tick timer operation in the timeline
 45 *			when the CPU returns from nohz sleep.
 46 * @next_tick:		Next tick to be fired when in dynticks mode.
 47 * @idle_jiffies:	jiffies at the entry to idle for idle time accounting
 48 * @idle_waketime:	Time when the idle was interrupted
 49 * @idle_sleeptime_seq:	sequence counter for data consistency
 50 * @idle_entrytime:	Time when the idle call was entered
 51 * @last_jiffies:	Base jiffies snapshot when next event was last computed
 52 * @timer_expires_base:	Base time clock monotonic for @timer_expires
 53 * @timer_expires:	Anticipated timer expiration time (in case sched tick is stopped)
 54 * @next_timer:		Expiry time of next expiring timer for debugging purpose only
 55 * @idle_expires:	Next tick in idle, for debugging purpose only
 56 * @idle_calls:		Total number of idle calls
 57 * @idle_sleeps:	Number of idle calls, where the sched tick was stopped
 58 * @idle_exittime:	Time when the idle state was left
 59 * @idle_sleeptime:	Sum of the time slept in idle with sched tick stopped
 60 * @iowait_sleeptime:	Sum of the time slept in idle with sched tick stopped, with IO outstanding
 61 * @tick_dep_mask:	Tick dependency mask - is set, if someone needs the tick
 62 * @check_clocks:	Notification mechanism about clocksource changes
 63 */
 64struct tick_sched {
 65	/* Common flags */
 66	unsigned long			flags;
 67
 68	/* Tick handling: jiffies stall check */
 69	unsigned int			stalled_jiffies;
 70	unsigned long			last_tick_jiffies;
 71
 72	/* Tick handling */
 73	struct hrtimer			sched_timer;
 74	ktime_t				last_tick;
 75	ktime_t				next_tick;
 76	unsigned long			idle_jiffies;
 77	ktime_t				idle_waketime;
 78	unsigned int			got_idle_tick;
 79
 80	/* Idle entry */
 81	seqcount_t			idle_sleeptime_seq;
 82	ktime_t				idle_entrytime;
 83
 84	/* Tick stop */
 85	unsigned long			last_jiffies;
 86	u64				timer_expires_base;
 87	u64				timer_expires;
 88	u64				next_timer;
 89	ktime_t				idle_expires;
 90	unsigned long			idle_calls;
 91	unsigned long			idle_sleeps;
 92
 93	/* Idle exit */
 94	ktime_t				idle_exittime;
 95	ktime_t				idle_sleeptime;
 96	ktime_t				iowait_sleeptime;
 97
 98	/* Full dynticks handling */
 99	atomic_t			tick_dep_mask;
100
101	/* Clocksource changes */
102	unsigned long			check_clocks;
103};
104
105extern struct tick_sched *tick_get_tick_sched(int cpu);
106
107extern void tick_setup_sched_timer(bool hrtimer);
108#if defined CONFIG_TICK_ONESHOT
109extern void tick_sched_timer_dying(int cpu);
110#else
111static inline void tick_sched_timer_dying(int cpu) { }
112#endif
113
114#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
115extern int __tick_broadcast_oneshot_control(enum tick_broadcast_state state);
116#else
117static inline int
118__tick_broadcast_oneshot_control(enum tick_broadcast_state state)
119{
120	return -EBUSY;
121}
122#endif
123
124#endif