root/include/linux/cpuidle.h

INCLUDED FROM

DEFINITIONS

1. cpuidle_get_statedata
2. cpuidle_set_statedata
3. cpuidle_get_last_residency
4. cpuidle_register_driver
5. cpuidle_unregister_driver
6. cpuidle_register_device
7. cpuidle_unregister_device
8. cpuidle_pause_and_lock
9. cpuidle_resume_and_unlock
10. cpuidle_enable_device
11. cpuidle_disable_device
12. cpuidle_register_governor
13. cpuidle_unregister_governor

/*
 * cpuidle.h - a generic framework for CPU idle power management
 *
 * (C) 2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
 *          Shaohua Li <shaohua.li@intel.com>
 *          Adam Belay <abelay@novell.com>
 *
 * This code is licenced under the GPL.
 */

#ifndef _LINUX_CPUIDLE_H
#define _LINUX_CPUIDLE_H

#include <linux/percpu.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/kobject.h>
#include <linux/completion.h>

#define CPUIDLE_STATE_MAX       8
#define CPUIDLE_NAME_LEN        16
#define CPUIDLE_DESC_LEN        32

struct cpuidle_device;


/****************************
 * CPUIDLE DEVICE INTERFACE *
 ****************************/

struct cpuidle_state {
        char            name[CPUIDLE_NAME_LEN];
        char            desc[CPUIDLE_DESC_LEN];
        void            *driver_data;

        unsigned int    flags;
        unsigned int    exit_latency; /* in US */
        unsigned int    power_usage; /* in mW */
        unsigned int    target_residency; /* in US */

        unsigned long long      usage;
        unsigned long long      time; /* in US */

        int (*enter)    (struct cpuidle_device *dev,
                         struct cpuidle_state *state);
};

/* Idle State Flags */
#define CPUIDLE_FLAG_TIME_VALID (0x01) /* is residency time measurable? */
#define CPUIDLE_FLAG_CHECK_BM   (0x02) /* BM activity will exit state */
#define CPUIDLE_FLAG_POLL       (0x10) /* no latency, no savings */
#define CPUIDLE_FLAG_SHALLOW    (0x20) /* low latency, minimal savings */
#define CPUIDLE_FLAG_BALANCED   (0x40) /* medium latency, moderate savings */
#define CPUIDLE_FLAG_DEEP       (0x80) /* high latency, large savings */

#define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)

/**
 * cpuidle_get_statedata - retrieves private driver state data
 * @state: the state
 */
static inline void * cpuidle_get_statedata(struct cpuidle_state *state)
{
        return state->driver_data;
}

/**
 * cpuidle_set_statedata - stores private driver state data
 * @state: the state
 * @data: the private data
 */
static inline void
cpuidle_set_statedata(struct cpuidle_state *state, void *data)
{
        state->driver_data = data;
}

struct cpuidle_state_kobj {
        struct cpuidle_state *state;
        struct completion kobj_unregister;
        struct kobject kobj;
};

struct cpuidle_device {
        unsigned int            registered:1;
        unsigned int            enabled:1;
        unsigned int            cpu;

        int                     last_residency;
        int                     state_count;
        struct cpuidle_state    states[CPUIDLE_STATE_MAX];
        struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
        struct cpuidle_state    *last_state;

        struct list_head        device_list;
        struct kobject          kobj;
        struct completion       kobj_unregister;
        void                    *governor_data;
        struct cpuidle_state    *safe_state;
};

DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);

/**
 * cpuidle_get_last_residency - retrieves the last state's residency time
 * @dev: the target CPU
 *
 * NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
 */
static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
{
        return dev->last_residency;
}


/****************************
 * CPUIDLE DRIVER INTERFACE *
 ****************************/

struct cpuidle_driver {
        char                    name[CPUIDLE_NAME_LEN];
        struct module           *owner;
};

#ifdef CONFIG_CPU_IDLE

extern int cpuidle_register_driver(struct cpuidle_driver *drv);
extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
extern int cpuidle_register_device(struct cpuidle_device *dev);
extern void cpuidle_unregister_device(struct cpuidle_device *dev);

extern void cpuidle_pause_and_lock(void);
extern void cpuidle_resume_and_unlock(void);
extern int cpuidle_enable_device(struct cpuidle_device *dev);
extern void cpuidle_disable_device(struct cpuidle_device *dev);

#else

static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
{return 0;}
static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
static inline int cpuidle_register_device(struct cpuidle_device *dev)
{return 0;}
static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }

static inline void cpuidle_pause_and_lock(void) { }
static inline void cpuidle_resume_and_unlock(void) { }
static inline int cpuidle_enable_device(struct cpuidle_device *dev)
{return 0;}
static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }

#endif

/******************************
 * CPUIDLE GOVERNOR INTERFACE *
 ******************************/

struct cpuidle_governor {
        char                    name[CPUIDLE_NAME_LEN];
        struct list_head        governor_list;
        unsigned int            rating;

        int  (*enable)          (struct cpuidle_device *dev);
        void (*disable)         (struct cpuidle_device *dev);

        int  (*select)          (struct cpuidle_device *dev);
        void (*reflect)         (struct cpuidle_device *dev);

        struct module           *owner;
};

#ifdef CONFIG_CPU_IDLE

extern int cpuidle_register_governor(struct cpuidle_governor *gov);
extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);

#else

static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
{return 0;}
static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }

#endif

#ifdef CONFIG_ARCH_HAS_CPU_RELAX
#define CPUIDLE_DRIVER_STATE_START      1
#else
#define CPUIDLE_DRIVER_STATE_START      0
#endif

#endif /* _LINUX_CPUIDLE_H */