linux/include/linux/cpuidle.h
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   1/*
   2 * cpuidle.h - a generic framework for CPU idle power management
   3 *
   4 * (C) 2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
   5 *          Shaohua Li <shaohua.li@intel.com>
   6 *          Adam Belay <abelay@novell.com>
   7 *
   8 * This code is licenced under the GPL.
   9 */
  10
  11#ifndef _LINUX_CPUIDLE_H
  12#define _LINUX_CPUIDLE_H
  13
  14#include <linux/percpu.h>
  15#include <linux/list.h>
  16#include <linux/kobject.h>
  17#include <linux/completion.h>
  18
  19#define CPUIDLE_STATE_MAX       8
  20#define CPUIDLE_NAME_LEN        16
  21#define CPUIDLE_DESC_LEN        32
  22
  23struct module;
  24
  25struct cpuidle_device;
  26struct cpuidle_driver;
  27
  28
  29/****************************
  30 * CPUIDLE DEVICE INTERFACE *
  31 ****************************/
  32
  33struct cpuidle_state_usage {
  34        void            *driver_data;
  35
  36        unsigned long long      usage;
  37        unsigned long long      time; /* in US */
  38};
  39
  40struct cpuidle_state {
  41        char            name[CPUIDLE_NAME_LEN];
  42        char            desc[CPUIDLE_DESC_LEN];
  43
  44        unsigned int    flags;
  45        unsigned int    exit_latency; /* in US */
  46        unsigned int    power_usage; /* in mW */
  47        unsigned int    target_residency; /* in US */
  48
  49        int (*enter)    (struct cpuidle_device *dev,
  50                        struct cpuidle_driver *drv,
  51                        int index);
  52};
  53
  54/* Idle State Flags */
  55#define CPUIDLE_FLAG_TIME_VALID (0x01) /* is residency time measurable? */
  56
  57#define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
  58
  59/**
  60 * cpuidle_get_statedata - retrieves private driver state data
  61 * @st_usage: the state usage statistics
  62 */
  63static inline void *cpuidle_get_statedata(struct cpuidle_state_usage *st_usage)
  64{
  65        return st_usage->driver_data;
  66}
  67
  68/**
  69 * cpuidle_set_statedata - stores private driver state data
  70 * @st_usage: the state usage statistics
  71 * @data: the private data
  72 */
  73static inline void
  74cpuidle_set_statedata(struct cpuidle_state_usage *st_usage, void *data)
  75{
  76        st_usage->driver_data = data;
  77}
  78
  79struct cpuidle_state_kobj {
  80        struct cpuidle_state *state;
  81        struct cpuidle_state_usage *state_usage;
  82        struct completion kobj_unregister;
  83        struct kobject kobj;
  84};
  85
  86struct cpuidle_device {
  87        unsigned int            registered:1;
  88        unsigned int            enabled:1;
  89        unsigned int            cpu;
  90
  91        int                     last_residency;
  92        int                     state_count;
  93        struct cpuidle_state_usage      states_usage[CPUIDLE_STATE_MAX];
  94        struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
  95
  96        struct list_head        device_list;
  97        struct kobject          kobj;
  98        struct completion       kobj_unregister;
  99        void                    *governor_data;
 100};
 101
 102DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
 103
 104/**
 105 * cpuidle_get_last_residency - retrieves the last state's residency time
 106 * @dev: the target CPU
 107 *
 108 * NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
 109 */
 110static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
 111{
 112        return dev->last_residency;
 113}
 114
 115
 116/****************************
 117 * CPUIDLE DRIVER INTERFACE *
 118 ****************************/
 119
 120struct cpuidle_driver {
 121        char                    name[CPUIDLE_NAME_LEN];
 122        struct module           *owner;
 123
 124        unsigned int            power_specified:1;
 125        struct cpuidle_state    states[CPUIDLE_STATE_MAX];
 126        int                     state_count;
 127        int                     safe_state_index;
 128};
 129
 130#ifdef CONFIG_CPU_IDLE
 131extern void disable_cpuidle(void);
 132extern int cpuidle_idle_call(void);
 133extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 134struct cpuidle_driver *cpuidle_get_driver(void);
 135extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 136extern int cpuidle_register_device(struct cpuidle_device *dev);
 137extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 138
 139extern void cpuidle_pause_and_lock(void);
 140extern void cpuidle_resume_and_unlock(void);
 141extern int cpuidle_enable_device(struct cpuidle_device *dev);
 142extern void cpuidle_disable_device(struct cpuidle_device *dev);
 143
 144#else
 145static inline void disable_cpuidle(void) { }
 146static inline int cpuidle_idle_call(void) { return -ENODEV; }
 147static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 148{return -ENODEV; }
 149static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
 150static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 151static inline int cpuidle_register_device(struct cpuidle_device *dev)
 152{return -ENODEV; }
 153static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 154
 155static inline void cpuidle_pause_and_lock(void) { }
 156static inline void cpuidle_resume_and_unlock(void) { }
 157static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 158{return -ENODEV; }
 159static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 160
 161#endif
 162
 163/******************************
 164 * CPUIDLE GOVERNOR INTERFACE *
 165 ******************************/
 166
 167struct cpuidle_governor {
 168        char                    name[CPUIDLE_NAME_LEN];
 169        struct list_head        governor_list;
 170        unsigned int            rating;
 171
 172        int  (*enable)          (struct cpuidle_driver *drv,
 173                                        struct cpuidle_device *dev);
 174        void (*disable)         (struct cpuidle_driver *drv,
 175                                        struct cpuidle_device *dev);
 176
 177        int  (*select)          (struct cpuidle_driver *drv,
 178                                        struct cpuidle_device *dev);
 179        void (*reflect)         (struct cpuidle_device *dev, int index);
 180
 181        struct module           *owner;
 182};
 183
 184#ifdef CONFIG_CPU_IDLE
 185
 186extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 187extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
 188
 189#ifdef CONFIG_INTEL_IDLE
 190extern int intel_idle_cpu_init(int cpu);
 191#else
 192static inline int intel_idle_cpu_init(int cpu) { return -1; }
 193#endif
 194
 195#else
 196static inline int intel_idle_cpu_init(int cpu) { return -1; }
 197
 198static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 199{return 0;}
 200static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
 201
 202#endif
 203
 204#ifdef CONFIG_ARCH_HAS_CPU_RELAX
 205#define CPUIDLE_DRIVER_STATE_START      1
 206#else
 207#define CPUIDLE_DRIVER_STATE_START      0
 208#endif
 209
 210#endif /* _LINUX_CPUIDLE_H */
 211
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