#ifndef _LINUX_TIMER_H
  #define _LINUX_TIMER_H
  
  #include <linux/list.h>
  #include <linux/ktime.h>
  #include <linux/stddef.h>
  #include <linux/debugobjects.h>
  #include <linux/stringify.h>
  
  struct tvec_base;
  
  struct timer_list {
  	/*
  	 * All fields that change during normal runtime grouped to the
  	 * same cacheline
  	 */
  	struct list_head entry;
  	unsigned long expires;
  	struct tvec_base *base;
  
  	void (*function)(unsigned long);
  	unsigned long data;
  
  	int slack;
  
  #ifdef CONFIG_TIMER_STATS
  	int start_pid;
  	void *start_site;
  	char start_comm[16];
  #endif
  #ifdef CONFIG_LOCKDEP
  	struct lockdep_map lockdep_map;
  #endif
  };
  
  extern struct tvec_base boot_tvec_bases;
  
  #ifdef CONFIG_LOCKDEP
  /*
   * NB: because we have to copy the lockdep_map, setting the lockdep_map key
   * (second argument) here is required, otherwise it could be initialised to
   * the copy of the lockdep_map later! We use the pointer to and the string
   * "<file>:<line>" as the key resp. the name of the lockdep_map.
   */
  #define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)				\
  	.lockdep_map = STATIC_LOCKDEP_MAP_INIT(_kn, &_kn),
  #else
  #define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)
  #endif
  
  /*
   * Note that all tvec_bases are at least 4 byte aligned and lower two bits
   * of base in timer_list is guaranteed to be zero. Use them for flags.
   *
   * A deferrable timer will work normally when the system is busy, but
   * will not cause a CPU to come out of idle just to service it; instead,
   * the timer will be serviced when the CPU eventually wakes up with a
   * subsequent non-deferrable timer.
   *
   * An irqsafe timer is executed with IRQ disabled and it's safe to wait for
   * the completion of the running instance from IRQ handlers, for example,
   * by calling del_timer_sync().
   *
   * Note: The irq disabled callback execution is a special case for
   * workqueue locking issues. It's not meant for executing random crap
   * with interrupts disabled. Abuse is monitored!
   */
  #define TIMER_DEFERRABLE		0x1LU
  #define TIMER_IRQSAFE			0x2LU
  
  #define TIMER_FLAG_MASK			0x3LU
  
  #define __TIMER_INITIALIZER(_function, _expires, _data, _flags) { \
  		.entry = { .prev = TIMER_ENTRY_STATIC },	\
  		.function = (_function),			\
  		.expires = (_expires),				\
  		.data = (_data),				\
  		.base = (void *)((unsigned long)&boot_tvec_bases + (_flags)), \
  		.slack = -1,					\
  		__TIMER_LOCKDEP_MAP_INITIALIZER(		\
  			__FILE__ ":" __stringify(__LINE__))	\
  	}
  
  #define TIMER_INITIALIZER(_function, _expires, _data)		\
  	__TIMER_INITIALIZER((_function), (_expires), (_data), 0)
  
  #define TIMER_DEFERRED_INITIALIZER(_function, _expires, _data)	\
  	__TIMER_INITIALIZER((_function), (_expires), (_data), TIMER_DEFERRABLE)
  
  #define DEFINE_TIMER(_name, _function, _expires, _data)		\
  	struct timer_list _name =				\
  		TIMER_INITIALIZER(_function, _expires, _data)
  
  void init_timer_key(struct timer_list *timer, unsigned int flags,
  		    const char *name, struct lock_class_key *key);
  
  #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
  extern void init_timer_on_stack_key(struct timer_list *timer,
  				    unsigned int flags, const char *name,
  				    struct lock_class_key *key);
  extern void destroy_timer_on_stack(struct timer_list *timer);
  #else
  static inline void destroy_timer_on_stack(struct timer_list *timer) { }
  static inline void init_timer_on_stack_key(struct timer_list *timer,
  					   unsigned int flags, const char *name,
  					   struct lock_class_key *key)
  {
  	init_timer_key(timer, flags, name, key);
  }
  #endif
  
  #ifdef CONFIG_LOCKDEP
  #define __init_timer(_timer, _flags)					\
  	do {								\
  		static struct lock_class_key __key;			\
  		init_timer_key((_timer), (_flags), #_timer, &__key);	\
  	} while (0)
  
  #define __init_timer_on_stack(_timer, _flags)				\
  	do {								\
  		static struct lock_class_key __key;			\
  		init_timer_on_stack_key((_timer), (_flags), #_timer, &__key); \
  	} while (0)
  #else
  #define __init_timer(_timer, _flags)					\
  	init_timer_key((_timer), (_flags), NULL, NULL)
  #define __init_timer_on_stack(_timer, _flags)				\
  	init_timer_on_stack_key((_timer), (_flags), NULL, NULL)
  #endif
  
  #define init_timer(timer)						\
  	__init_timer((timer), 0)
  #define init_timer_deferrable(timer)					\
  	__init_timer((timer), TIMER_DEFERRABLE)
  #define init_timer_on_stack(timer)					\
  	__init_timer_on_stack((timer), 0)
  
  #define __setup_timer(_timer, _fn, _data, _flags)			\
  	do {								\
  		__init_timer((_timer), (_flags));			\
  		(_timer)->function = (_fn);				\
  		(_timer)->data = (_data);				\
  	} while (0)
  
  #define __setup_timer_on_stack(_timer, _fn, _data, _flags)		\
  	do {								\
  		__init_timer_on_stack((_timer), (_flags));		\
  		(_timer)->function = (_fn);				\
  		(_timer)->data = (_data);				\
  	} while (0)
  
  #define setup_timer(timer, fn, data)					\
  	__setup_timer((timer), (fn), (data), 0)
  #define setup_timer_on_stack(timer, fn, data)				\
  	__setup_timer_on_stack((timer), (fn), (data), 0)
  #define setup_deferrable_timer_on_stack(timer, fn, data)		\
  	__setup_timer_on_stack((timer), (fn), (data), TIMER_DEFERRABLE)
  
  /**
   * timer_pending - is a timer pending?
   * @timer: the timer in question
   *
   * timer_pending will tell whether a given timer is currently pending,
   * or not. Callers must ensure serialization wrt. other operations done
   * to this timer, eg. interrupt contexts, or other CPUs on SMP.
   *
   * return value: 1 if the timer is pending, 0 if not.
   */
  static inline int timer_pending(const struct timer_list * timer)
  {
  	return timer->entry.next != NULL;
  }
  
  extern void add_timer_on(struct timer_list *timer, int cpu);
  extern int del_timer(struct timer_list * timer);
  extern int mod_timer(struct timer_list *timer, unsigned long expires);
  extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
  extern int mod_timer_pinned(struct timer_list *timer, unsigned long expires);
  
  extern void set_timer_slack(struct timer_list *time, int slack_hz);
  
  #define TIMER_NOT_PINNED	0
  #define TIMER_PINNED		1
  /*
   * The jiffies value which is added to now, when there is no timer
   * in the timer wheel:
   */
  #define NEXT_TIMER_MAX_DELTA	((1UL << 30) - 1)
  
  /*
   * Return when the next timer-wheel timeout occurs (in absolute jiffies),
   * locks the timer base and does the comparison against the given
   * jiffie.
   */
  extern unsigned long get_next_timer_interrupt(unsigned long now);
  
  /*
   * Timer-statistics info:
   */
  #ifdef CONFIG_TIMER_STATS
  
  extern int timer_stats_active;
  
  #define TIMER_STATS_FLAG_DEFERRABLE	0x1
  
  extern void init_timer_stats(void);
  
  extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
  				     void *timerf, char *comm,
  				     unsigned int timer_flag);
  
  extern void __timer_stats_timer_set_start_info(struct timer_list *timer,
  					       void *addr);
  
  static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
  {
  	if (likely(!timer_stats_active))
  		return;
  	__timer_stats_timer_set_start_info(timer, __builtin_return_address(0));
  }
  
  static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
  {
  	timer->start_site = NULL;
  }
  #else
  static inline void init_timer_stats(void)
  {
  }
  
  static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
  {
  }
  
  static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
  {
  }
  #endif
  
  extern void add_timer(struct timer_list *timer);
  
  extern int try_to_del_timer_sync(struct timer_list *timer);
  
  #ifdef CONFIG_SMP
    extern int del_timer_sync(struct timer_list *timer);
  #else
  # define del_timer_sync(t)		del_timer(t)
  #endif
  
  #define del_singleshot_timer_sync(t) del_timer_sync(t)
  
  extern void init_timers(void);
  extern void run_local_timers(void);
  struct hrtimer;
  extern enum hrtimer_restart it_real_fn(struct hrtimer *);
  
  unsigned long __round_jiffies(unsigned long j, int cpu);
  unsigned long __round_jiffies_relative(unsigned long j, int cpu);
  unsigned long round_jiffies(unsigned long j);
  unsigned long round_jiffies_relative(unsigned long j);
  
  unsigned long __round_jiffies_up(unsigned long j, int cpu);
  unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
  unsigned long round_jiffies_up(unsigned long j);
  unsigned long round_jiffies_up_relative(unsigned long j);
  
  #endif