1. 根目录:
2. include
3. linux
4. suspend.h

#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_get_active_wakeup_sources(char *pending_sources, size_t max);
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 */