include/linux/suspend.h - kernel/msm-4.19 - Gitiles

 /* SPDX-License-Identifier: GPL-2.0 */
 #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 void pm_prepare_console(void);
 extern void pm_restore_console(void);
 #else
 static inline void pm_prepare_console(void)
 {
 }

 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_TO_IDLE	((__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_TO_IDLE
 #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);
 };

 struct platform_s2idle_ops {
 	int (*begin)(void);
 	int (*prepare)(void);
 	void (*wake)(void);
 	void (*sync)(void);
 	void (*restore)(void);
 	void (*end)(void);
 };

 #ifdef CONFIG_SUSPEND
 extern suspend_state_t mem_sleep_current;
 extern suspend_state_t mem_sleep_default;

 /**
  * 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 unsigned int pm_suspend_global_flags;

 #define PM_SUSPEND_FLAG_FW_SUSPEND	(1 << 0)
 #define PM_SUSPEND_FLAG_FW_RESUME	(1 << 1)

 static inline void pm_suspend_clear_flags(void)
 {
 	pm_suspend_global_flags = 0;
 }

 static inline void pm_set_suspend_via_firmware(void)
 {
 	pm_suspend_global_flags |= PM_SUSPEND_FLAG_FW_SUSPEND;
 }

 static inline void pm_set_resume_via_firmware(void)
 {
 	pm_suspend_global_flags |= PM_SUSPEND_FLAG_FW_RESUME;
 }

 static inline bool pm_suspend_via_firmware(void)
 {
 	return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_FW_SUSPEND);
 }

 static inline bool pm_resume_via_firmware(void)
 {
 	return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_FW_RESUME);
 }

 /* Suspend-to-idle state machnine. */
 enum s2idle_states {
 	S2IDLE_STATE_NONE,      /* Not suspended/suspending. */
 	S2IDLE_STATE_ENTER,     /* Enter suspend-to-idle. */
 	S2IDLE_STATE_WAKE,      /* Wake up from suspend-to-idle. */
 };

 extern enum s2idle_states __read_mostly s2idle_state;

 static inline bool idle_should_enter_s2idle(void)
 {
 	return unlikely(s2idle_state == S2IDLE_STATE_ENTER);
 }

 extern bool pm_suspend_via_s2idle(void);
 extern void __init pm_states_init(void);
 extern void s2idle_set_ops(const struct platform_s2idle_ops *ops);
 extern void s2idle_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 pm_suspend_clear_flags(void) {}
 static inline void pm_set_suspend_via_firmware(void) {}
 static inline void pm_set_resume_via_firmware(void) {}
 static inline bool pm_suspend_via_firmware(void) { return false; }
 static inline bool pm_resume_via_firmware(void) { return false; }
 static inline bool pm_suspend_via_s2idle(void) { return false; }

 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 bool idle_should_enter_s2idle(void) { return false; }
 static inline void __init pm_states_init(void) {}
 static inline void s2idle_set_ops(const struct platform_s2idle_ops *ops) {}
 static inline void s2idle_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 asmlinkage int swsusp_arch_suspend(void);
 extern asmlinkage int swsusp_arch_resume(void);

 extern void hibernation_set_ops(const struct platform_hibernation_ops *ops);
 extern int hibernate(void);
 extern bool system_entering_hibernation(void);
 extern bool hibernation_available(void);
 asmlinkage int swsusp_save(void);
 extern struct pbe *restore_pblist;
 #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; }
 static inline bool hibernation_available(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 system_transition_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 unsigned int pm_wakeup_irq;
 extern suspend_state_t pm_suspend_target_state;

 extern bool pm_wakeup_pending(void);
 extern void pm_system_wakeup(void);
 extern void pm_system_cancel_wakeup(void);
 extern void pm_wakeup_clear(bool reset);
 extern void pm_system_irq_wakeup(unsigned int irq_number);
 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);
 extern void pm_get_active_wakeup_sources(char *pending_sources, size_t max);

 extern void lock_system_sleep(void);
 extern void unlock_system_sleep(void);

 #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 pm_system_wakeup(void) {}
 static inline void pm_wakeup_clear(bool reset) {}
 static inline void pm_system_irq_wakeup(unsigned int irq_number) {}

 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;
 extern bool pm_debug_messages_on;
 extern __printf(2, 3) void __pm_pr_dbg(bool defer, const char *fmt, ...);
 #else
 #define pm_print_times_enabled	(false)
 #define pm_debug_messages_on	(false)

 #include <linux/printk.h>

 #define __pm_pr_dbg(defer, fmt, ...) \
 	no_printk(KERN_DEBUG fmt, ##__VA_ARGS__)
 #endif

 #define pm_pr_dbg(fmt, ...) \
 	__pm_pr_dbg(false, fmt, ##__VA_ARGS__)

 #define pm_deferred_pr_dbg(fmt, ...) \
 	__pm_pr_dbg(true, fmt, ##__VA_ARGS__)

 #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 */
	/* SPDX-License-Identifier: GPL-2.0 */
	#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 void pm_prepare_console(void);
	extern void pm_restore_console(void);
	#else
	static inline void pm_prepare_console(void)
	{
	}

	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_TO_IDLE ((__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_TO_IDLE
	#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);
	};

	struct platform_s2idle_ops {
	int (*begin)(void);
	int (*prepare)(void);
	void (*wake)(void);
	void (*sync)(void);
	void (*restore)(void);
	void (*end)(void);
	};

	#ifdef CONFIG_SUSPEND
	extern suspend_state_t mem_sleep_current;
	extern suspend_state_t mem_sleep_default;

	/**
	* 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 unsigned int pm_suspend_global_flags;

	#define PM_SUSPEND_FLAG_FW_SUSPEND (1 << 0)
	#define PM_SUSPEND_FLAG_FW_RESUME (1 << 1)

	static inline void pm_suspend_clear_flags(void)
	{
	pm_suspend_global_flags = 0;
	}

	static inline void pm_set_suspend_via_firmware(void)
	{
	pm_suspend_global_flags \|= PM_SUSPEND_FLAG_FW_SUSPEND;
	}

	static inline void pm_set_resume_via_firmware(void)
	{
	pm_suspend_global_flags \|= PM_SUSPEND_FLAG_FW_RESUME;
	}

	static inline bool pm_suspend_via_firmware(void)
	{
	return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_FW_SUSPEND);
	}

	static inline bool pm_resume_via_firmware(void)
	{
	return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_FW_RESUME);
	}

	/* Suspend-to-idle state machnine. */
	enum s2idle_states {
	S2IDLE_STATE_NONE, /* Not suspended/suspending. */
	S2IDLE_STATE_ENTER, /* Enter suspend-to-idle. */
	S2IDLE_STATE_WAKE, /* Wake up from suspend-to-idle. */
	};

	extern enum s2idle_states __read_mostly s2idle_state;

	static inline bool idle_should_enter_s2idle(void)
	{
	return unlikely(s2idle_state == S2IDLE_STATE_ENTER);
	}

	extern bool pm_suspend_via_s2idle(void);
	extern void __init pm_states_init(void);
	extern void s2idle_set_ops(const struct platform_s2idle_ops *ops);
	extern void s2idle_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 pm_suspend_clear_flags(void) {}
	static inline void pm_set_suspend_via_firmware(void) {}
	static inline void pm_set_resume_via_firmware(void) {}
	static inline bool pm_suspend_via_firmware(void) { return false; }
	static inline bool pm_resume_via_firmware(void) { return false; }
	static inline bool pm_suspend_via_s2idle(void) { return false; }

	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 bool idle_should_enter_s2idle(void) { return false; }
	static inline void __init pm_states_init(void) {}
	static inline void s2idle_set_ops(const struct platform_s2idle_ops *ops) {}
	static inline void s2idle_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 asmlinkage int swsusp_arch_suspend(void);
	extern asmlinkage int swsusp_arch_resume(void);

	extern void hibernation_set_ops(const struct platform_hibernation_ops *ops);
	extern int hibernate(void);
	extern bool system_entering_hibernation(void);
	extern bool hibernation_available(void);
	asmlinkage int swsusp_save(void);
	extern struct pbe *restore_pblist;
	#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; }
	static inline bool hibernation_available(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 system_transition_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 unsigned int pm_wakeup_irq;
	extern suspend_state_t pm_suspend_target_state;

	extern bool pm_wakeup_pending(void);
	extern void pm_system_wakeup(void);
	extern void pm_system_cancel_wakeup(void);
	extern void pm_wakeup_clear(bool reset);
	extern void pm_system_irq_wakeup(unsigned int irq_number);
	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);
	extern void pm_get_active_wakeup_sources(char *pending_sources, size_t max);

	extern void lock_system_sleep(void);
	extern void unlock_system_sleep(void);

	#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 pm_system_wakeup(void) {}
	static inline void pm_wakeup_clear(bool reset) {}
	static inline void pm_system_irq_wakeup(unsigned int irq_number) {}

	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;
	extern bool pm_debug_messages_on;
	extern __printf(2, 3) void __pm_pr_dbg(bool defer, const char *fmt, ...);
	#else
	#define pm_print_times_enabled (false)
	#define pm_debug_messages_on (false)

	#include <linux/printk.h>

	#define __pm_pr_dbg(defer, fmt, ...) \
	no_printk(KERN_DEBUG fmt, ##__VA_ARGS__)
	#endif

	#define pm_pr_dbg(fmt, ...) \
	__pm_pr_dbg(false, fmt, ##__VA_ARGS__)

	#define pm_deferred_pr_dbg(fmt, ...) \
	__pm_pr_dbg(true, fmt, ##__VA_ARGS__)

	#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 */