#ifndef _LINUX_SUSPEND_H
  #define _LINUX_SUSPEND_H
  
  #include <linux/swap.h>
  #include <linux/notifier.h>
  #include <linux/init.h>
  #include <linux/pm.h>
  #include <linux/mm.h>
  #include <linux/freezer.h>
  #include <asm/errno.h>
  
  #ifdef CONFIG_VT
  extern void pm_set_vt_switch(int);
  #else
  static inline void pm_set_vt_switch(int do_switch)
  {
  }
  #endif
  
  #ifdef CONFIG_VT_CONSOLE_SLEEP
  extern int pm_prepare_console(void);
  extern void pm_restore_console(void);
  #else
  static inline int pm_prepare_console(void)
  {
  	return 0;
  }
  
  static inline void pm_restore_console(void)
  {
  }
  #endif
  
  typedef int __bitwise suspend_state_t;
  
  #define PM_SUSPEND_ON		((__force suspend_state_t) 0)
  #define PM_SUSPEND_FREEZE	((__force suspend_state_t) 1)
  #define PM_SUSPEND_STANDBY	((__force suspend_state_t) 2)
  #define PM_SUSPEND_MEM		((__force suspend_state_t) 3)
  #define PM_SUSPEND_MIN		PM_SUSPEND_FREEZE
  #define PM_SUSPEND_MAX		((__force suspend_state_t) 4)
  
  enum suspend_stat_step {
  	SUSPEND_FREEZE = 1,
  	SUSPEND_PREPARE,
  	SUSPEND_SUSPEND,
  	SUSPEND_SUSPEND_LATE,
  	SUSPEND_SUSPEND_NOIRQ,
  	SUSPEND_RESUME_NOIRQ,
  	SUSPEND_RESUME_EARLY,
  	SUSPEND_RESUME
  };
  
  struct suspend_stats {
  	int	success;
  	int	fail;
  	int	failed_freeze;
  	int	failed_prepare;
  	int	failed_suspend;
  	int	failed_suspend_late;
  	int	failed_suspend_noirq;
  	int	failed_resume;
  	int	failed_resume_early;
  	int	failed_resume_noirq;
  #define	REC_FAILED_NUM	2
  	int	last_failed_dev;
  	char	failed_devs[REC_FAILED_NUM][40];
  	int	last_failed_errno;
  	int	errno[REC_FAILED_NUM];
  	int	last_failed_step;
  	enum suspend_stat_step	failed_steps[REC_FAILED_NUM];
  };
  
  extern struct suspend_stats suspend_stats;
  
  static inline void dpm_save_failed_dev(const char *name)
  {
  	strlcpy(suspend_stats.failed_devs[suspend_stats.last_failed_dev],
  		name,
  		sizeof(suspend_stats.failed_devs[0]));
  	suspend_stats.last_failed_dev++;
  	suspend_stats.last_failed_dev %= REC_FAILED_NUM;
  }
  
  static inline void dpm_save_failed_errno(int err)
  {
  	suspend_stats.errno[suspend_stats.last_failed_errno] = err;
  	suspend_stats.last_failed_errno++;
  	suspend_stats.last_failed_errno %= REC_FAILED_NUM;
  }
  
  static inline void dpm_save_failed_step(enum suspend_stat_step step)
  {
  	suspend_stats.failed_steps[suspend_stats.last_failed_step] = step;
  	suspend_stats.last_failed_step++;
  	suspend_stats.last_failed_step %= REC_FAILED_NUM;
  }
  
  /**
   * struct platform_suspend_ops - Callbacks for managing platform dependent
   *	system sleep states.
   *
   * @valid: Callback to determine if given system sleep state is supported by
   *	the platform.
   *	Valid (ie. supported) states are advertised in /sys/power/state.  Note
   *	that it still may be impossible to enter given system sleep state if the
   *	conditions aren't right.
   *	There is the %suspend_valid_only_mem function available that can be
   *	assigned to this if the platform only supports mem sleep.
   *
   * @begin: Initialise a transition to given system sleep state.
   *	@begin() is executed right prior to suspending devices.  The information
   *	conveyed to the platform code by @begin() should be disregarded by it as
   *	soon as @end() is executed.  If @begin() fails (ie. returns nonzero),
   *	@prepare(), @enter() and @finish() will not be called by the PM core.
   *	This callback is optional.  However, if it is implemented, the argument
   *	passed to @enter() is redundant and should be ignored.
   *
   * @prepare: Prepare the platform for entering the system sleep state indicated
   *	by @begin().
   *	@prepare() is called right after devices have been suspended (ie. the
   *	appropriate .suspend() method has been executed for each device) and
   *	before device drivers' late suspend callbacks are executed.  It returns
   *	0 on success or a negative error code otherwise, in which case the
   *	system cannot enter the desired sleep state (@prepare_late(), @enter(),
   *	and @wake() will not be called in that case).
   *
   * @prepare_late: Finish preparing the platform for entering the system sleep
   *	state indicated by @begin().
   *	@prepare_late is called before disabling nonboot CPUs and after
   *	device drivers' late suspend callbacks have been executed.  It returns
   *	0 on success or a negative error code otherwise, in which case the
   *	system cannot enter the desired sleep state (@enter() will not be
   *	executed).
   *
   * @enter: Enter the system sleep state indicated by @begin() or represented by
   *	the argument if @begin() is not implemented.
   *	This callback is mandatory.  It returns 0 on success or a negative
   *	error code otherwise, in which case the system cannot enter the desired
   *	sleep state.
   *
   * @wake: Called when the system has just left a sleep state, right after
   *	the nonboot CPUs have been enabled and before device drivers' early
   *	resume callbacks are executed.
   *	This callback is optional, but should be implemented by the platforms
   *	that implement @prepare_late().  If implemented, it is always called
   *	after @prepare_late and @enter(), even if one of them fails.
   *
   * @finish: Finish wake-up of the platform.
   *	@finish is called right prior to calling device drivers' regular suspend
   *	callbacks.
   *	This callback is optional, but should be implemented by the platforms
   *	that implement @prepare().  If implemented, it is always called after
   *	@enter() and @wake(), even if any of them fails.  It is executed after
   *	a failing @prepare.
   *
   * @suspend_again: Returns whether the system should suspend again (true) or
   *	not (false). If the platform wants to poll sensors or execute some
   *	code during suspended without invoking userspace and most of devices,
   *	suspend_again callback is the place assuming that periodic-wakeup or
   *	alarm-wakeup is already setup. This allows to execute some codes while
   *	being kept suspended in the view of userland and devices.
   *
   * @end: Called by the PM core right after resuming devices, to indicate to
   *	the platform that the system has returned to the working state or
   *	the transition to the sleep state has been aborted.
   *	This callback is optional, but should be implemented by the platforms
   *	that implement @begin().  Accordingly, platforms implementing @begin()
   *	should also provide a @end() which cleans up transitions aborted before
   *	@enter().
   *
   * @recover: Recover the platform from a suspend failure.
   *	Called by the PM core if the suspending of devices fails.
   *	This callback is optional and should only be implemented by platforms
   *	which require special recovery actions in that situation.
   */
  struct platform_suspend_ops {
  	int (*valid)(suspend_state_t state);
  	int (*begin)(suspend_state_t state);
  	int (*prepare)(void);
  	int (*prepare_late)(void);
  	int (*enter)(suspend_state_t state);
  	void (*wake)(void);
  	void (*finish)(void);
  	bool (*suspend_again)(void);
  	void (*end)(void);
  	void (*recover)(void);
  };
  
  #ifdef CONFIG_SUSPEND
  /**
   * suspend_set_ops - set platform dependent suspend operations
   * @ops: The new suspend operations to set.
   */
  extern void suspend_set_ops(const struct platform_suspend_ops *ops);
  extern int suspend_valid_only_mem(suspend_state_t state);
  extern void freeze_wake(void);
  
  /**
   * arch_suspend_disable_irqs - disable IRQs for suspend
   *
   * Disables IRQs (in the default case). This is a weak symbol in the common
   * code and thus allows architectures to override it if more needs to be
   * done. Not called for suspend to disk.
   */
  extern void arch_suspend_disable_irqs(void);
  
  /**
   * arch_suspend_enable_irqs - enable IRQs after suspend
   *
   * Enables IRQs (in the default case). This is a weak symbol in the common
   * code and thus allows architectures to override it if more needs to be
   * done. Not called for suspend to disk.
   */
  extern void arch_suspend_enable_irqs(void);
  
  extern int pm_suspend(suspend_state_t state);
  #else /* !CONFIG_SUSPEND */
  #define suspend_valid_only_mem	NULL
  
  static inline void suspend_set_ops(const struct platform_suspend_ops *ops) {}
  static inline int pm_suspend(suspend_state_t state) { return -ENOSYS; }
  static inline void freeze_wake(void) {}
  #endif /* !CONFIG_SUSPEND */
  
  /* struct pbe is used for creating lists of pages that should be restored
   * atomically during the resume from disk, because the page frames they have
   * occupied before the suspend are in use.
   */
  struct pbe {
  	void *address;		/* address of the copy */
  	void *orig_address;	/* original address of a page */
  	struct pbe *next;
  };
  
  /* mm/page_alloc.c */
  extern void mark_free_pages(struct zone *zone);
  
  /**
   * struct platform_hibernation_ops - hibernation platform support
   *
   * The methods in this structure allow a platform to carry out special
   * operations required by it during a hibernation transition.
   *
   * All the methods below, except for @recover(), must be implemented.
   *
   * @begin: Tell the platform driver that we're starting hibernation.
   *	Called right after shrinking memory and before freezing devices.
   *
   * @end: Called by the PM core right after resuming devices, to indicate to
   *	the platform that the system has returned to the working state.
   *
   * @pre_snapshot: Prepare the platform for creating the hibernation image.
   *	Called right after devices have been frozen and before the nonboot
   *	CPUs are disabled (runs with IRQs on).
   *
   * @finish: Restore the previous state of the platform after the hibernation
   *	image has been created *or* put the platform into the normal operation
   *	mode after the hibernation (the same method is executed in both cases).
   *	Called right after the nonboot CPUs have been enabled and before
   *	thawing devices (runs with IRQs on).
   *
   * @prepare: Prepare the platform for entering the low power state.
   *	Called right after the hibernation image has been saved and before
   *	devices are prepared for entering the low power state.
   *
   * @enter: Put the system into the low power state after the hibernation image
   *	has been saved to disk.
   *	Called after the nonboot CPUs have been disabled and all of the low
   *	level devices have been shut down (runs with IRQs off).
   *
   * @leave: Perform the first stage of the cleanup after the system sleep state
   *	indicated by @set_target() has been left.
   *	Called right after the control has been passed from the boot kernel to
   *	the image kernel, before the nonboot CPUs are enabled and before devices
   *	are resumed.  Executed with interrupts disabled.
   *
   * @pre_restore: Prepare system for the restoration from a hibernation image.
   *	Called right after devices have been frozen and before the nonboot
   *	CPUs are disabled (runs with IRQs on).
   *
   * @restore_cleanup: Clean up after a failing image restoration.
   *	Called right after the nonboot CPUs have been enabled and before
   *	thawing devices (runs with IRQs on).
   *
   * @recover: Recover the platform from a failure to suspend devices.
   *	Called by the PM core if the suspending of devices during hibernation
   *	fails.  This callback is optional and should only be implemented by
   *	platforms which require special recovery actions in that situation.
   */
  struct platform_hibernation_ops {
  	int (*begin)(void);
  	void (*end)(void);
  	int (*pre_snapshot)(void);
  	void (*finish)(void);
  	int (*prepare)(void);
  	int (*enter)(void);
  	void (*leave)(void);
  	int (*pre_restore)(void);
  	void (*restore_cleanup)(void);
  	void (*recover)(void);
  };
  
  #ifdef CONFIG_HIBERNATION
  /* kernel/power/snapshot.c */
  extern void __register_nosave_region(unsigned long b, unsigned long e, int km);
  static inline void __init register_nosave_region(unsigned long b, unsigned long e)
  {
  	__register_nosave_region(b, e, 0);
  }
  static inline void __init register_nosave_region_late(unsigned long b, unsigned long e)
  {
  	__register_nosave_region(b, e, 1);
  }
  extern int swsusp_page_is_forbidden(struct page *);
  extern void swsusp_set_page_free(struct page *);
  extern void swsusp_unset_page_free(struct page *);
  extern unsigned long get_safe_page(gfp_t gfp_mask);
  
  extern void hibernation_set_ops(const struct platform_hibernation_ops *ops);
  extern int hibernate(void);
  extern bool system_entering_hibernation(void);
  #else /* CONFIG_HIBERNATION */
  static inline void register_nosave_region(unsigned long b, unsigned long e) {}
  static inline void register_nosave_region_late(unsigned long b, unsigned long e) {}
  static inline int swsusp_page_is_forbidden(struct page *p) { return 0; }
  static inline void swsusp_set_page_free(struct page *p) {}
  static inline void swsusp_unset_page_free(struct page *p) {}
  
  static inline void hibernation_set_ops(const struct platform_hibernation_ops *ops) {}
  static inline int hibernate(void) { return -ENOSYS; }
  static inline bool system_entering_hibernation(void) { return false; }
  #endif /* CONFIG_HIBERNATION */
  
  /* Hibernation and suspend events */
  #define PM_HIBERNATION_PREPARE	0x0001 /* Going to hibernate */
  #define PM_POST_HIBERNATION	0x0002 /* Hibernation finished */
  #define PM_SUSPEND_PREPARE	0x0003 /* Going to suspend the system */
  #define PM_POST_SUSPEND		0x0004 /* Suspend finished */
  #define PM_RESTORE_PREPARE	0x0005 /* Going to restore a saved image */
  #define PM_POST_RESTORE		0x0006 /* Restore failed */
  
  extern struct mutex pm_mutex;
  
  #ifdef CONFIG_PM_SLEEP
  void save_processor_state(void);
  void restore_processor_state(void);
  
  /* kernel/power/main.c */
  extern int register_pm_notifier(struct notifier_block *nb);
  extern int unregister_pm_notifier(struct notifier_block *nb);
  
  #define pm_notifier(fn, pri) {				\
  	static struct notifier_block fn##_nb =			\
  		{ .notifier_call = fn, .priority = pri };	\
  	register_pm_notifier(&fn##_nb);			\
  }
  
  /* drivers/base/power/wakeup.c */
  extern bool events_check_enabled;
  
  extern bool pm_wakeup_pending(void);
  extern bool pm_get_wakeup_count(unsigned int *count, bool block);
  extern bool pm_save_wakeup_count(unsigned int count);
  extern void pm_wakep_autosleep_enabled(bool set);
  extern void pm_print_active_wakeup_sources(void);
  
  static inline void lock_system_sleep(void)
  {
  	current->flags |= PF_FREEZER_SKIP;
  	mutex_lock(&pm_mutex);
  }
  
  static inline void unlock_system_sleep(void)
  {
  	/*
  	 * Don't use freezer_count() because we don't want the call to
  	 * try_to_freeze() here.
  	 *
  	 * Reason:
  	 * Fundamentally, we just don't need it, because freezing condition
  	 * doesn't come into effect until we release the pm_mutex lock,
  	 * since the freezer always works with pm_mutex held.
  	 *
  	 * More importantly, in the case of hibernation,
  	 * unlock_system_sleep() gets called in snapshot_read() and
  	 * snapshot_write() when the freezing condition is still in effect.
  	 * Which means, if we use try_to_freeze() here, it would make them
  	 * enter the refrigerator, thus causing hibernation to lockup.
  	 */
  	current->flags &= ~PF_FREEZER_SKIP;
  	mutex_unlock(&pm_mutex);
  }
  
  #else /* !CONFIG_PM_SLEEP */
  
  static inline int register_pm_notifier(struct notifier_block *nb)
  {
  	return 0;
  }
  
  static inline int unregister_pm_notifier(struct notifier_block *nb)
  {
  	return 0;
  }
  
  #define pm_notifier(fn, pri)	do { (void)(fn); } while (0)
  
  static inline bool pm_wakeup_pending(void) { return false; }
  
  static inline void lock_system_sleep(void) {}
  static inline void unlock_system_sleep(void) {}
  
  #endif /* !CONFIG_PM_SLEEP */
  
  #ifdef CONFIG_PM_SLEEP_DEBUG
  extern bool pm_print_times_enabled;
  #else
  #define pm_print_times_enabled	(false)
  #endif
  
  #ifdef CONFIG_PM_AUTOSLEEP
  
  /* kernel/power/autosleep.c */
  void queue_up_suspend_work(void);
  
  #else /* !CONFIG_PM_AUTOSLEEP */
  
  static inline void queue_up_suspend_work(void) {}
  
  #endif /* !CONFIG_PM_AUTOSLEEP */
  
  #ifdef CONFIG_ARCH_SAVE_PAGE_KEYS
  /*
   * The ARCH_SAVE_PAGE_KEYS functions can be used by an architecture
   * to save/restore additional information to/from the array of page
   * frame numbers in the hibernation image. For s390 this is used to
   * save and restore the storage key for each page that is included
   * in the hibernation image.
   */
  unsigned long page_key_additional_pages(unsigned long pages);
  int page_key_alloc(unsigned long pages);
  void page_key_free(void);
  void page_key_read(unsigned long *pfn);
  void page_key_memorize(unsigned long *pfn);
  void page_key_write(void *address);
  
  #else /* !CONFIG_ARCH_SAVE_PAGE_KEYS */
  
  static inline unsigned long page_key_additional_pages(unsigned long pages)
  {
  	return 0;
  }
  
  static inline int  page_key_alloc(unsigned long pages)
  {
  	return 0;
  }
  
  static inline void page_key_free(void) {}
  static inline void page_key_read(unsigned long *pfn) {}
  static inline void page_key_memorize(unsigned long *pfn) {}
  static inline void page_key_write(void *address) {}
  
  #endif /* !CONFIG_ARCH_SAVE_PAGE_KEYS */
  
  #endif /* _LINUX_SUSPEND_H */