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        unsigned long long      disable;
  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        int             power_usage; /* in mW */
  47        unsigned int    target_residency; /* in US */
  48        bool            disabled; /* disabled on all CPUs */
  49
  50        int (*enter)    (struct cpuidle_device *dev,
  51                        struct cpuidle_driver *drv,
  52                        int index);
  53
  54        int (*enter_dead) (struct cpuidle_device *dev, int index);
  55};
  56
  57/* Idle State Flags */
  58#define CPUIDLE_FLAG_TIME_VALID (0x01) /* is residency time measurable? */
  59#define CPUIDLE_FLAG_COUPLED    (0x02) /* state applies to multiple cpus */
  60
  61#define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
  62
  63struct cpuidle_device {
  64        unsigned int            registered:1;
  65        unsigned int            enabled:1;
  66        unsigned int            cpu;
  67
  68        int                     last_residency;
  69        int                     state_count;
  70        struct cpuidle_state_usage      states_usage[CPUIDLE_STATE_MAX];
  71        struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
  72        struct cpuidle_driver_kobj *kobj_driver;
  73        struct list_head        device_list;
  74        struct kobject          kobj;
  75        struct completion       kobj_unregister;
  76
  77#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
  78        int                     safe_state_index;
  79        cpumask_t               coupled_cpus;
  80        struct cpuidle_coupled  *coupled;
  81#endif
  82};
  83
  84DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
  85
  86/**
  87 * cpuidle_get_last_residency - retrieves the last state's residency time
  88 * @dev: the target CPU
  89 *
  90 * NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
  91 */
  92static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
  93{
  94        return dev->last_residency;
  95}
  96
  97
  98/****************************
  99 * CPUIDLE DRIVER INTERFACE *
 100 ****************************/
 101
 102struct cpuidle_driver {
 103        const char              *name;
 104        struct module           *owner;
 105        int                     refcnt;
 106
 107        /* set to 1 to use the core cpuidle time keeping (for all states). */
 108        unsigned int            en_core_tk_irqen:1;
 109        /* states array must be ordered in decreasing power consumption */
 110        struct cpuidle_state    states[CPUIDLE_STATE_MAX];
 111        int                     state_count;
 112        int                     safe_state_index;
 113};
 114
 115#ifdef CONFIG_CPU_IDLE
 116extern void disable_cpuidle(void);
 117extern int cpuidle_idle_call(void);
 118extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 119extern struct cpuidle_driver *cpuidle_get_driver(void);
 120extern struct cpuidle_driver *cpuidle_driver_ref(void);
 121extern void cpuidle_driver_unref(void);
 122extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 123extern int cpuidle_register_device(struct cpuidle_device *dev);
 124extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 125
 126extern void cpuidle_pause_and_lock(void);
 127extern void cpuidle_resume_and_unlock(void);
 128extern void cpuidle_pause(void);
 129extern void cpuidle_resume(void);
 130extern int cpuidle_enable_device(struct cpuidle_device *dev);
 131extern void cpuidle_disable_device(struct cpuidle_device *dev);
 132extern int cpuidle_wrap_enter(struct cpuidle_device *dev,
 133                                struct cpuidle_driver *drv, int index,
 134                                int (*enter)(struct cpuidle_device *dev,
 135                                        struct cpuidle_driver *drv, int index));
 136extern int cpuidle_play_dead(void);
 137
 138extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
 139extern int cpuidle_register_cpu_driver(struct cpuidle_driver *drv, int cpu);
 140extern void cpuidle_unregister_cpu_driver(struct cpuidle_driver *drv, int cpu);
 141
 142#else
 143static inline void disable_cpuidle(void) { }
 144static inline int cpuidle_idle_call(void) { return -ENODEV; }
 145static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 146{return -ENODEV; }
 147static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
 148static inline struct cpuidle_driver *cpuidle_driver_ref(void) {return NULL; }
 149static inline void cpuidle_driver_unref(void) {}
 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 void cpuidle_pause(void) { }
 158static inline void cpuidle_resume(void) { }
 159static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 160{return -ENODEV; }
 161static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 162static inline int cpuidle_wrap_enter(struct cpuidle_device *dev,
 163                                struct cpuidle_driver *drv, int index,
 164                                int (*enter)(struct cpuidle_device *dev,
 165                                        struct cpuidle_driver *drv, int index))
 166{ return -ENODEV; }
 167static inline int cpuidle_play_dead(void) {return -ENODEV; }
 168#endif
 169
 170#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
 171void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a);
 172#else
 173static inline void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a)
 174{
 175}
 176#endif
 177
 178/******************************
 179 * CPUIDLE GOVERNOR INTERFACE *
 180 ******************************/
 181
 182struct cpuidle_governor {
 183        char                    name[CPUIDLE_NAME_LEN];
 184        struct list_head        governor_list;
 185        unsigned int            rating;
 186
 187        int  (*enable)          (struct cpuidle_driver *drv,
 188                                        struct cpuidle_device *dev);
 189        void (*disable)         (struct cpuidle_driver *drv,
 190                                        struct cpuidle_device *dev);
 191
 192        int  (*select)          (struct cpuidle_driver *drv,
 193                                        struct cpuidle_device *dev);
 194        void (*reflect)         (struct cpuidle_device *dev, int index);
 195
 196        struct module           *owner;
 197};
 198
 199#ifdef CONFIG_CPU_IDLE
 200
 201extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 202extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
 203
 204#else
 205
 206static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 207{return 0;}
 208static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
 209
 210#endif
 211
 212#ifdef CONFIG_ARCH_HAS_CPU_RELAX
 213#define CPUIDLE_DRIVER_STATE_START      1
 214#else
 215#define CPUIDLE_DRIVER_STATE_START      0
 216#endif
 217
 218#endif /* _LINUX_CPUIDLE_H */
 219
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