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/hrtimer.h>
  17
  18#define CPUIDLE_STATE_MAX       10
  19#define CPUIDLE_NAME_LEN        16
  20#define CPUIDLE_DESC_LEN        32
  21
  22struct module;
  23
  24struct cpuidle_device;
  25struct cpuidle_driver;
  26
  27
  28/****************************
  29 * CPUIDLE DEVICE INTERFACE *
  30 ****************************/
  31
  32struct cpuidle_state_usage {
  33        unsigned long long      disable;
  34        unsigned long long      usage;
  35        unsigned long long      time; /* in US */
  36};
  37
  38struct cpuidle_state {
  39        char            name[CPUIDLE_NAME_LEN];
  40        char            desc[CPUIDLE_DESC_LEN];
  41
  42        unsigned int    flags;
  43        unsigned int    exit_latency; /* in US */
  44        int             power_usage; /* in mW */
  45        unsigned int    target_residency; /* in US */
  46        bool            disabled; /* disabled on all CPUs */
  47
  48        int (*enter)    (struct cpuidle_device *dev,
  49                        struct cpuidle_driver *drv,
  50                        int index);
  51
  52        int (*enter_dead) (struct cpuidle_device *dev, int index);
  53
  54        /*
  55         * CPUs execute ->enter_s2idle with the local tick or entire timekeeping
  56         * suspended, so it must not re-enable interrupts at any point (even
  57         * temporarily) or attempt to change states of clock event devices.
  58         */
  59        void (*enter_s2idle) (struct cpuidle_device *dev,
  60                              struct cpuidle_driver *drv,
  61                              int index);
  62};
  63
  64/* Idle State Flags */
  65#define CPUIDLE_FLAG_NONE       (0x00)
  66#define CPUIDLE_FLAG_POLLING    (0x01) /* polling state */
  67#define CPUIDLE_FLAG_COUPLED    (0x02) /* state applies to multiple cpus */
  68#define CPUIDLE_FLAG_TIMER_STOP (0x04)  /* timer is stopped on this state */
  69
  70#define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
  71
  72struct cpuidle_device_kobj;
  73struct cpuidle_state_kobj;
  74struct cpuidle_driver_kobj;
  75
  76struct cpuidle_device {
  77        unsigned int            registered:1;
  78        unsigned int            enabled:1;
  79        unsigned int            use_deepest_state:1;
  80        unsigned int            cpu;
  81
  82        int                     last_residency;
  83        struct cpuidle_state_usage      states_usage[CPUIDLE_STATE_MAX];
  84        struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
  85        struct cpuidle_driver_kobj *kobj_driver;
  86        struct cpuidle_device_kobj *kobj_dev;
  87        struct list_head        device_list;
  88
  89#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
  90        cpumask_t               coupled_cpus;
  91        struct cpuidle_coupled  *coupled;
  92#endif
  93};
  94
  95DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
  96DECLARE_PER_CPU(struct cpuidle_device, cpuidle_dev);
  97
  98/**
  99 * cpuidle_get_last_residency - retrieves the last state's residency time
 100 * @dev: the target CPU
 101 */
 102static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
 103{
 104        return dev->last_residency;
 105}
 106
 107
 108/****************************
 109 * CPUIDLE DRIVER INTERFACE *
 110 ****************************/
 111
 112struct cpuidle_driver {
 113        const char              *name;
 114        struct module           *owner;
 115        int                     refcnt;
 116
 117        /* used by the cpuidle framework to setup the broadcast timer */
 118        unsigned int            bctimer:1;
 119        /* states array must be ordered in decreasing power consumption */
 120        struct cpuidle_state    states[CPUIDLE_STATE_MAX];
 121        int                     state_count;
 122        int                     safe_state_index;
 123
 124        /* the driver handles the cpus in cpumask */
 125        struct cpumask          *cpumask;
 126};
 127
 128#ifdef CONFIG_CPU_IDLE
 129extern void disable_cpuidle(void);
 130extern bool cpuidle_not_available(struct cpuidle_driver *drv,
 131                                  struct cpuidle_device *dev);
 132
 133extern int cpuidle_select(struct cpuidle_driver *drv,
 134                          struct cpuidle_device *dev);
 135extern int cpuidle_enter(struct cpuidle_driver *drv,
 136                         struct cpuidle_device *dev, int index);
 137extern void cpuidle_reflect(struct cpuidle_device *dev, int index);
 138
 139extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 140extern struct cpuidle_driver *cpuidle_get_driver(void);
 141extern struct cpuidle_driver *cpuidle_driver_ref(void);
 142extern void cpuidle_driver_unref(void);
 143extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 144extern int cpuidle_register_device(struct cpuidle_device *dev);
 145extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 146extern int cpuidle_register(struct cpuidle_driver *drv,
 147                            const struct cpumask *const coupled_cpus);
 148extern void cpuidle_unregister(struct cpuidle_driver *drv);
 149extern void cpuidle_pause_and_lock(void);
 150extern void cpuidle_resume_and_unlock(void);
 151extern void cpuidle_pause(void);
 152extern void cpuidle_resume(void);
 153extern int cpuidle_enable_device(struct cpuidle_device *dev);
 154extern void cpuidle_disable_device(struct cpuidle_device *dev);
 155extern int cpuidle_play_dead(void);
 156
 157extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
 158static inline struct cpuidle_device *cpuidle_get_device(void)
 159{return __this_cpu_read(cpuidle_devices); }
 160#else
 161static inline void disable_cpuidle(void) { }
 162static inline bool cpuidle_not_available(struct cpuidle_driver *drv,
 163                                         struct cpuidle_device *dev)
 164{return true; }
 165static inline int cpuidle_select(struct cpuidle_driver *drv,
 166                                 struct cpuidle_device *dev)
 167{return -ENODEV; }
 168static inline int cpuidle_enter(struct cpuidle_driver *drv,
 169                                struct cpuidle_device *dev, int index)
 170{return -ENODEV; }
 171static inline void cpuidle_reflect(struct cpuidle_device *dev, int index) { }
 172static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 173{return -ENODEV; }
 174static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
 175static inline struct cpuidle_driver *cpuidle_driver_ref(void) {return NULL; }
 176static inline void cpuidle_driver_unref(void) {}
 177static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 178static inline int cpuidle_register_device(struct cpuidle_device *dev)
 179{return -ENODEV; }
 180static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 181static inline int cpuidle_register(struct cpuidle_driver *drv,
 182                                   const struct cpumask *const coupled_cpus)
 183{return -ENODEV; }
 184static inline void cpuidle_unregister(struct cpuidle_driver *drv) { }
 185static inline void cpuidle_pause_and_lock(void) { }
 186static inline void cpuidle_resume_and_unlock(void) { }
 187static inline void cpuidle_pause(void) { }
 188static inline void cpuidle_resume(void) { }
 189static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 190{return -ENODEV; }
 191static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 192static inline int cpuidle_play_dead(void) {return -ENODEV; }
 193static inline struct cpuidle_driver *cpuidle_get_cpu_driver(
 194        struct cpuidle_device *dev) {return NULL; }
 195static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; }
 196#endif
 197
 198#ifdef CONFIG_CPU_IDLE
 199extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
 200                                      struct cpuidle_device *dev);
 201extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
 202                                struct cpuidle_device *dev);
 203extern void cpuidle_use_deepest_state(bool enable);
 204#else
 205static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
 206                                             struct cpuidle_device *dev)
 207{return -ENODEV; }
 208static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
 209                                       struct cpuidle_device *dev)
 210{return -ENODEV; }
 211static inline void cpuidle_use_deepest_state(bool enable)
 212{
 213}
 214#endif
 215
 216/* kernel/sched/idle.c */
 217extern void sched_idle_set_state(struct cpuidle_state *idle_state);
 218extern void default_idle_call(void);
 219
 220#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
 221void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a);
 222#else
 223static inline void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a)
 224{
 225}
 226#endif
 227
 228#ifdef CONFIG_ARCH_HAS_CPU_RELAX
 229void cpuidle_poll_state_init(struct cpuidle_driver *drv);
 230#else
 231static inline void cpuidle_poll_state_init(struct cpuidle_driver *drv) {}
 232#endif
 233
 234/******************************
 235 * CPUIDLE GOVERNOR INTERFACE *
 236 ******************************/
 237
 238struct cpuidle_governor {
 239        char                    name[CPUIDLE_NAME_LEN];
 240        struct list_head        governor_list;
 241        unsigned int            rating;
 242
 243        int  (*enable)          (struct cpuidle_driver *drv,
 244                                        struct cpuidle_device *dev);
 245        void (*disable)         (struct cpuidle_driver *drv,
 246                                        struct cpuidle_device *dev);
 247
 248        int  (*select)          (struct cpuidle_driver *drv,
 249                                        struct cpuidle_device *dev);
 250        void (*reflect)         (struct cpuidle_device *dev, int index);
 251};
 252
 253#ifdef CONFIG_CPU_IDLE
 254extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 255#else
 256static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 257{return 0;}
 258#endif
 259
 260#define CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx)        \
 261({                                                              \
 262        int __ret;                                              \
 263                                                                \
 264        if (!idx) {                                             \
 265                cpu_do_idle();                                  \
 266                return idx;                                     \
 267        }                                                       \
 268                                                                \
 269        __ret = cpu_pm_enter();                                 \
 270        if (!__ret) {                                           \
 271                __ret = low_level_idle_enter(idx);              \
 272                cpu_pm_exit();                                  \
 273        }                                                       \
 274                                                                \
 275        __ret ? -1 : idx;                                       \
 276})
 277
 278#endif /* _LINUX_CPUIDLE_H */
 279
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