tick.h

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/*  linux/include/linux/tick.h
 *
 *  This file contains the structure definitions for tick related functions
 *
 */
#ifndef _LINUX_TICK_H
#define _LINUX_TICK_H

#include <linux/clockchips.h>
#include <linux/irqflags.h>

#ifdef CONFIG_GENERIC_CLOCKEVENTS

enum tick_device_mode {
    TICKDEV_MODE_PERIODIC,
    TICKDEV_MODE_ONESHOT,
};

struct tick_device {
    struct clock_event_device *evtdev;
    enum tick_device_mode mode;
};

enum tick_nohz_mode {
    NOHZ_MODE_INACTIVE,
    NOHZ_MODE_LOWRES,
    NOHZ_MODE_HIGHRES,
};

struct tick_sched {
    struct hrtimer          sched_timer;
    unsigned long           check_clocks;
    enum tick_nohz_mode     nohz_mode;
    ktime_t             last_tick;
    int             inidle;
    int             tick_stopped;
    unsigned long           idle_jiffies;
    unsigned long           idle_calls;
    unsigned long           idle_sleeps;
    int             idle_active;
    ktime_t             idle_entrytime;
    ktime_t             idle_waketime;
    ktime_t             idle_exittime;
    ktime_t             idle_sleeptime;
    ktime_t             iowait_sleeptime;
    ktime_t             sleep_length;
    unsigned long           last_jiffies;
    unsigned long           next_jiffies;
    ktime_t             idle_expires;
    int             do_timer_last;
};

extern void __init tick_init(void);
extern int tick_is_oneshot_available(void);
extern struct tick_device *tick_get_device(int cpu);

# ifdef CONFIG_HIGH_RES_TIMERS
extern int tick_init_highres(void);
extern int tick_program_event(ktime_t expires, int force);
extern void tick_setup_sched_timer(void);
# endif

# if defined CONFIG_NO_HZ || defined CONFIG_HIGH_RES_TIMERS
extern void tick_cancel_sched_timer(int cpu);
# else
static inline void tick_cancel_sched_timer(int cpu) { }
# endif

# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
extern struct tick_device *tick_get_broadcast_device(void);
extern struct cpumask *tick_get_broadcast_mask(void);

#  ifdef CONFIG_TICK_ONESHOT
extern struct cpumask *tick_get_broadcast_oneshot_mask(void);
#  endif

# endif /* BROADCAST */

# ifdef CONFIG_TICK_ONESHOT
extern void tick_clock_notify(void);
extern int tick_check_oneshot_change(int allow_nohz);
extern struct tick_sched *tick_get_tick_sched(int cpu);
extern void tick_check_idle(int cpu);
extern int tick_oneshot_mode_active(void);
#  ifndef arch_needs_cpu
#   define arch_needs_cpu(cpu) (0)
#  endif
# else
static inline void tick_clock_notify(void) { }
static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
static inline void tick_check_idle(int cpu) { }
static inline int tick_oneshot_mode_active(void) { return 0; }
# endif

#else /* CONFIG_GENERIC_CLOCKEVENTS */
static inline void tick_init(void) { }
static inline void tick_cancel_sched_timer(int cpu) { }
static inline void tick_clock_notify(void) { }
static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
static inline void tick_check_idle(int cpu) { }
static inline int tick_oneshot_mode_active(void) { return 0; }
#endif /* !CONFIG_GENERIC_CLOCKEVENTS */

# ifdef CONFIG_NO_HZ
extern void tick_nohz_idle_enter(void);
extern void tick_nohz_idle_exit(void);
extern void tick_nohz_irq_exit(void);
extern ktime_t tick_nohz_get_sleep_length(void);
extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
# else
static inline void tick_nohz_idle_enter(void) { }
static inline void tick_nohz_idle_exit(void) { }

static inline ktime_t tick_nohz_get_sleep_length(void)
{
    ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };

    return len;
}
static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
# endif /* !NO_HZ */

#endif