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#include <linux/hrtimer.h>
  19
  20#define CPUIDLE_STATE_MAX       8
  21#define CPUIDLE_NAME_LEN        16
  22#define CPUIDLE_DESC_LEN        32
  23
  24struct module;
  25
  26struct cpuidle_device;
  27struct cpuidle_driver;
  28
  29
  30/****************************
  31 * CPUIDLE DEVICE INTERFACE *
  32 ****************************/
  33
  34struct cpuidle_state_usage {
  35        void            *driver_data;
  36
  37        unsigned long long      disable;
  38        unsigned long long      usage;
  39        unsigned long long      time; /* in US */
  40};
  41
  42struct cpuidle_state {
  43        char            name[CPUIDLE_NAME_LEN];
  44        char            desc[CPUIDLE_DESC_LEN];
  45
  46        unsigned int    flags;
  47        unsigned int    exit_latency; /* in US */
  48        int             power_usage; /* in mW */
  49        unsigned int    target_residency; /* in US */
  50        bool            disabled; /* disabled on all CPUs */
  51
  52        int (*enter)    (struct cpuidle_device *dev,
  53                        struct cpuidle_driver *drv,
  54                        int index);
  55
  56        int (*enter_dead) (struct cpuidle_device *dev, int index);
  57};
  58
  59/* Idle State Flags */
  60#define CPUIDLE_FLAG_TIME_VALID (0x01) /* is residency time measurable? */
  61#define CPUIDLE_FLAG_COUPLED    (0x02) /* state applies to multiple cpus */
  62
  63#define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
  64
  65/**
  66 * cpuidle_get_statedata - retrieves private driver state data
  67 * @st_usage: the state usage statistics
  68 */
  69static inline void *cpuidle_get_statedata(struct cpuidle_state_usage *st_usage)
  70{
  71        return st_usage->driver_data;
  72}
  73
  74/**
  75 * cpuidle_set_statedata - stores private driver state data
  76 * @st_usage: the state usage statistics
  77 * @data: the private data
  78 */
  79static inline void
  80cpuidle_set_statedata(struct cpuidle_state_usage *st_usage, void *data)
  81{
  82        st_usage->driver_data = data;
  83}
  84
  85struct cpuidle_state_kobj {
  86        struct cpuidle_state *state;
  87        struct cpuidle_state_usage *state_usage;
  88        struct completion kobj_unregister;
  89        struct kobject kobj;
  90};
  91
  92struct cpuidle_device {
  93        unsigned int            registered:1;
  94        unsigned int            enabled:1;
  95        unsigned int            cpu;
  96
  97        int                     last_residency;
  98        int                     state_count;
  99        struct cpuidle_state_usage      states_usage[CPUIDLE_STATE_MAX];
 100        struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
 101
 102        struct list_head        device_list;
 103        struct kobject          kobj;
 104        struct completion       kobj_unregister;
 105
 106#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
 107        int                     safe_state_index;
 108        cpumask_t               coupled_cpus;
 109        struct cpuidle_coupled  *coupled;
 110#endif
 111};
 112
 113DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
 114
 115/**
 116 * cpuidle_get_last_residency - retrieves the last state's residency time
 117 * @dev: the target CPU
 118 *
 119 * NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
 120 */
 121static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
 122{
 123        return dev->last_residency;
 124}
 125
 126
 127/****************************
 128 * CPUIDLE DRIVER INTERFACE *
 129 ****************************/
 130
 131struct cpuidle_driver {
 132        const char              *name;
 133        struct module           *owner;
 134
 135        unsigned int            power_specified:1;
 136        /* set to 1 to use the core cpuidle time keeping (for all states). */
 137        unsigned int            en_core_tk_irqen:1;
 138        struct cpuidle_state    states[CPUIDLE_STATE_MAX];
 139        int                     state_count;
 140        int                     safe_state_index;
 141};
 142
 143#ifdef CONFIG_CPU_IDLE
 144extern void disable_cpuidle(void);
 145extern int cpuidle_idle_call(void);
 146extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 147extern struct cpuidle_driver *cpuidle_get_driver(void);
 148extern struct cpuidle_driver *cpuidle_driver_ref(void);
 149extern void cpuidle_driver_unref(void);
 150extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 151extern int cpuidle_register_device(struct cpuidle_device *dev);
 152extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 153
 154extern void cpuidle_pause_and_lock(void);
 155extern void cpuidle_resume_and_unlock(void);
 156extern void cpuidle_pause(void);
 157extern void cpuidle_resume(void);
 158extern int cpuidle_enable_device(struct cpuidle_device *dev);
 159extern void cpuidle_disable_device(struct cpuidle_device *dev);
 160extern int cpuidle_wrap_enter(struct cpuidle_device *dev,
 161                                struct cpuidle_driver *drv, int index,
 162                                int (*enter)(struct cpuidle_device *dev,
 163                                        struct cpuidle_driver *drv, int index));
 164extern int cpuidle_play_dead(void);
 165
 166#else
 167static inline void disable_cpuidle(void) { }
 168static inline int cpuidle_idle_call(void) { return -ENODEV; }
 169static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 170{return -ENODEV; }
 171static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
 172static inline struct cpuidle_driver *cpuidle_driver_ref(void) {return NULL; }
 173static inline void cpuidle_driver_unref(void) {}
 174static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 175static inline int cpuidle_register_device(struct cpuidle_device *dev)
 176{return -ENODEV; }
 177static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 178
 179static inline void cpuidle_pause_and_lock(void) { }
 180static inline void cpuidle_resume_and_unlock(void) { }
 181static inline void cpuidle_pause(void) { }
 182static inline void cpuidle_resume(void) { }
 183static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 184{return -ENODEV; }
 185static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 186static inline int cpuidle_wrap_enter(struct cpuidle_device *dev,
 187                                struct cpuidle_driver *drv, int index,
 188                                int (*enter)(struct cpuidle_device *dev,
 189                                        struct cpuidle_driver *drv, int index))
 190{ return -ENODEV; }
 191static inline int cpuidle_play_dead(void) {return -ENODEV; }
 192
 193#endif
 194
 195#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
 196void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a);
 197#else
 198static inline void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a)
 199{
 200}
 201#endif
 202
 203/******************************
 204 * CPUIDLE GOVERNOR INTERFACE *
 205 ******************************/
 206
 207struct cpuidle_governor {
 208        char                    name[CPUIDLE_NAME_LEN];
 209        struct list_head        governor_list;
 210        unsigned int            rating;
 211
 212        int  (*enable)          (struct cpuidle_driver *drv,
 213                                        struct cpuidle_device *dev);
 214        void (*disable)         (struct cpuidle_driver *drv,
 215                                        struct cpuidle_device *dev);
 216
 217        int  (*select)          (struct cpuidle_driver *drv,
 218                                        struct cpuidle_device *dev);
 219        void (*reflect)         (struct cpuidle_device *dev, int index);
 220
 221        struct module           *owner;
 222};
 223
 224#ifdef CONFIG_CPU_IDLE
 225
 226extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 227extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
 228
 229#else
 230
 231static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 232{return 0;}
 233static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
 234
 235#endif
 236
 237#ifdef CONFIG_ARCH_HAS_CPU_RELAX
 238#define CPUIDLE_DRIVER_STATE_START      1
 239#else
 240#define CPUIDLE_DRIVER_STATE_START      0
 241#endif
 242
 243#endif /* _LINUX_CPUIDLE_H */
 244
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