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_device {
  86        unsigned int            registered:1;
  87        unsigned int            enabled:1;
  88        unsigned int            cpu;
  89
  90        int                     last_residency;
  91        int                     state_count;
  92        struct cpuidle_state_usage      states_usage[CPUIDLE_STATE_MAX];
  93        struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
  94        struct cpuidle_driver_kobj *kobj_driver;
  95        struct list_head        device_list;
  96        struct kobject          kobj;
  97        struct completion       kobj_unregister;
  98
  99#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
 100        int                     safe_state_index;
 101        cpumask_t               coupled_cpus;
 102        struct cpuidle_coupled  *coupled;
 103#endif
 104};
 105
 106DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
 107
 108/**
 109 * cpuidle_get_last_residency - retrieves the last state's residency time
 110 * @dev: the target CPU
 111 *
 112 * NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
 113 */
 114static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
 115{
 116        return dev->last_residency;
 117}
 118
 119
 120/****************************
 121 * CPUIDLE DRIVER INTERFACE *
 122 ****************************/
 123
 124struct cpuidle_driver {
 125        const char              *name;
 126        struct module           *owner;
 127        int                     refcnt;
 128
 129        /* set to 1 to use the core cpuidle time keeping (for all states). */
 130        unsigned int            en_core_tk_irqen:1;
 131        /* states array must be ordered in decreasing power consumption */
 132        struct cpuidle_state    states[CPUIDLE_STATE_MAX];
 133        int                     state_count;
 134        int                     safe_state_index;
 135};
 136
 137#ifdef CONFIG_CPU_IDLE
 138extern void disable_cpuidle(void);
 139extern int cpuidle_idle_call(void);
 140extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 141extern struct cpuidle_driver *cpuidle_get_driver(void);
 142extern struct cpuidle_driver *cpuidle_driver_ref(void);
 143extern void cpuidle_driver_unref(void);
 144extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 145extern int cpuidle_register_device(struct cpuidle_device *dev);
 146extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 147
 148extern void cpuidle_pause_and_lock(void);
 149extern void cpuidle_resume_and_unlock(void);
 150extern void cpuidle_pause(void);
 151extern void cpuidle_resume(void);
 152extern int cpuidle_enable_device(struct cpuidle_device *dev);
 153extern void cpuidle_disable_device(struct cpuidle_device *dev);
 154extern int cpuidle_wrap_enter(struct cpuidle_device *dev,
 155                                struct cpuidle_driver *drv, int index,
 156                                int (*enter)(struct cpuidle_device *dev,
 157                                        struct cpuidle_driver *drv, int index));
 158extern int cpuidle_play_dead(void);
 159
 160extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
 161extern int cpuidle_register_cpu_driver(struct cpuidle_driver *drv, int cpu);
 162extern void cpuidle_unregister_cpu_driver(struct cpuidle_driver *drv, int cpu);
 163
 164#else
 165static inline void disable_cpuidle(void) { }
 166static inline int cpuidle_idle_call(void) { return -ENODEV; }
 167static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 168{return -ENODEV; }
 169static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
 170static inline struct cpuidle_driver *cpuidle_driver_ref(void) {return NULL; }
 171static inline void cpuidle_driver_unref(void) {}
 172static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 173static inline int cpuidle_register_device(struct cpuidle_device *dev)
 174{return -ENODEV; }
 175static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 176
 177static inline void cpuidle_pause_and_lock(void) { }
 178static inline void cpuidle_resume_and_unlock(void) { }
 179static inline void cpuidle_pause(void) { }
 180static inline void cpuidle_resume(void) { }
 181static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 182{return -ENODEV; }
 183static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 184static inline int cpuidle_wrap_enter(struct cpuidle_device *dev,
 185                                struct cpuidle_driver *drv, int index,
 186                                int (*enter)(struct cpuidle_device *dev,
 187                                        struct cpuidle_driver *drv, int index))
 188{ return -ENODEV; }
 189static inline int cpuidle_play_dead(void) {return -ENODEV; }
 190#endif
 191
 192#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
 193void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a);
 194#else
 195static inline void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a)
 196{
 197}
 198#endif
 199
 200/******************************
 201 * CPUIDLE GOVERNOR INTERFACE *
 202 ******************************/
 203
 204struct cpuidle_governor {
 205        char                    name[CPUIDLE_NAME_LEN];
 206        struct list_head        governor_list;
 207        unsigned int            rating;
 208
 209        int  (*enable)          (struct cpuidle_driver *drv,
 210                                        struct cpuidle_device *dev);
 211        void (*disable)         (struct cpuidle_driver *drv,
 212                                        struct cpuidle_device *dev);
 213
 214        int  (*select)          (struct cpuidle_driver *drv,
 215                                        struct cpuidle_device *dev);
 216        void (*reflect)         (struct cpuidle_device *dev, int index);
 217
 218        struct module           *owner;
 219};
 220
 221#ifdef CONFIG_CPU_IDLE
 222
 223extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 224extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
 225
 226#else
 227
 228static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 229{return 0;}
 230static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
 231
 232#endif
 233
 234#ifdef CONFIG_ARCH_HAS_CPU_RELAX
 235#define CPUIDLE_DRIVER_STATE_START      1
 236#else
 237#define CPUIDLE_DRIVER_STATE_START      0
 238#endif
 239
 240#endif /* _LINUX_CPUIDLE_H */
 241
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