/*  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 - sched tick emulation and no idle tick control/stats
   * @sched_timer:	hrtimer to schedule the periodic tick in high
   *			resolution mode
   * @idle_tick:		Store the last idle tick expiry time when the tick
   *			timer is modified for idle sleeps. This is necessary
   *			to resume the tick timer operation in the timeline
   *			when the CPU returns from idle
   * @tick_stopped:	Indicator that the idle tick has been stopped
   * @idle_jiffies:	jiffies at the entry to idle for idle time accounting
   * @idle_calls:		Total number of idle calls
   * @idle_sleeps:	Number of idle calls, where the sched tick was stopped
   * @idle_entrytime:	Time when the idle call was entered

   * @idle_waketime:	Time when the idle was interrupted
   * @idle_exittime:	Time when the idle state was left

   * @idle_sleeptime:	Sum of the time slept in idle with sched tick stopped

   * @iowait_sleeptime:	Sum of the time slept in idle with sched tick stopped, with IO outstanding

   * @sleep_length:	Duration of the current idle sleep

   * @do_timer_lst:	CPU was the last one doing do_timer before going idle

   */
  struct tick_sched {
  	struct hrtimer			sched_timer;
  	unsigned long			check_clocks;
  	enum tick_nohz_mode		nohz_mode;
  	ktime_t				idle_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