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        unsigned long long      above; /* Number of times it's been too deep */
  37        unsigned long long      below; /* Number of times it's been too shallow */
  38#ifdef CONFIG_SUSPEND
  39        unsigned long long      s2idle_usage;
  40        unsigned long long      s2idle_time; /* in US */
  41#endif
  42};
  43
  44struct cpuidle_state {
  45        char            name[CPUIDLE_NAME_LEN];
  46        char            desc[CPUIDLE_DESC_LEN];
  47
  48        unsigned int    flags;
  49        unsigned int    exit_latency; /* in US */
  50        int             power_usage; /* in mW */
  51        unsigned int    target_residency; /* in US */
  52        bool            disabled; /* disabled on all CPUs */
  53
  54        int (*enter)    (struct cpuidle_device *dev,
  55                        struct cpuidle_driver *drv,
  56                        int index);
  57
  58        int (*enter_dead) (struct cpuidle_device *dev, int index);
  59
  60        /*
  61         * CPUs execute ->enter_s2idle with the local tick or entire timekeeping
  62         * suspended, so it must not re-enable interrupts at any point (even
  63         * temporarily) or attempt to change states of clock event devices.
  64         */
  65        void (*enter_s2idle) (struct cpuidle_device *dev,
  66                              struct cpuidle_driver *drv,
  67                              int index);
  68};
  69
  70/* Idle State Flags */
  71#define CPUIDLE_FLAG_NONE       (0x00)
  72#define CPUIDLE_FLAG_POLLING    BIT(0) /* polling state */
  73#define CPUIDLE_FLAG_COUPLED    BIT(1) /* state applies to multiple cpus */
  74#define CPUIDLE_FLAG_TIMER_STOP BIT(2) /* timer is stopped on this state */
  75
  76struct cpuidle_device_kobj;
  77struct cpuidle_state_kobj;
  78struct cpuidle_driver_kobj;
  79
  80struct cpuidle_device {
  81        unsigned int            registered:1;
  82        unsigned int            enabled:1;
  83        unsigned int            use_deepest_state:1;
  84        unsigned int            poll_time_limit:1;
  85        unsigned int            cpu;
  86        ktime_t                 next_hrtimer;
  87
  88        int                     last_state_idx;
  89        int                     last_residency;
  90        u64                     poll_limit_ns;
  91        struct cpuidle_state_usage      states_usage[CPUIDLE_STATE_MAX];
  92        struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
  93        struct cpuidle_driver_kobj *kobj_driver;
  94        struct cpuidle_device_kobj *kobj_dev;
  95        struct list_head        device_list;
  96
  97#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
  98        cpumask_t               coupled_cpus;
  99        struct cpuidle_coupled  *coupled;
 100#endif
 101};
 102
 103DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
 104DECLARE_PER_CPU(struct cpuidle_device, cpuidle_dev);
 105
 106/****************************
 107 * CPUIDLE DRIVER INTERFACE *
 108 ****************************/
 109
 110struct cpuidle_driver {
 111        const char              *name;
 112        struct module           *owner;
 113        int                     refcnt;
 114
 115        /* used by the cpuidle framework to setup the broadcast timer */
 116        unsigned int            bctimer:1;
 117        /* states array must be ordered in decreasing power consumption */
 118        struct cpuidle_state    states[CPUIDLE_STATE_MAX];
 119        int                     state_count;
 120        int                     safe_state_index;
 121
 122        /* the driver handles the cpus in cpumask */
 123        struct cpumask          *cpumask;
 124
 125        /* preferred governor to switch at register time */
 126        const char              *governor;
 127};
 128
 129#ifdef CONFIG_CPU_IDLE
 130extern void disable_cpuidle(void);
 131extern bool cpuidle_not_available(struct cpuidle_driver *drv,
 132                                  struct cpuidle_device *dev);
 133
 134extern int cpuidle_select(struct cpuidle_driver *drv,
 135                          struct cpuidle_device *dev,
 136                          bool *stop_tick);
 137extern int cpuidle_enter(struct cpuidle_driver *drv,
 138                         struct cpuidle_device *dev, int index);
 139extern void cpuidle_reflect(struct cpuidle_device *dev, int index);
 140extern u64 cpuidle_poll_time(struct cpuidle_driver *drv,
 141                             struct cpuidle_device *dev);
 142
 143extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 144extern struct cpuidle_driver *cpuidle_get_driver(void);
 145extern struct cpuidle_driver *cpuidle_driver_ref(void);
 146extern void cpuidle_driver_unref(void);
 147extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 148extern int cpuidle_register_device(struct cpuidle_device *dev);
 149extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 150extern int cpuidle_register(struct cpuidle_driver *drv,
 151                            const struct cpumask *const coupled_cpus);
 152extern void cpuidle_unregister(struct cpuidle_driver *drv);
 153extern void cpuidle_pause_and_lock(void);
 154extern void cpuidle_resume_and_unlock(void);
 155extern void cpuidle_pause(void);
 156extern void cpuidle_resume(void);
 157extern int cpuidle_enable_device(struct cpuidle_device *dev);
 158extern void cpuidle_disable_device(struct cpuidle_device *dev);
 159extern int cpuidle_play_dead(void);
 160
 161extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
 162static inline struct cpuidle_device *cpuidle_get_device(void)
 163{return __this_cpu_read(cpuidle_devices); }
 164#else
 165static inline void disable_cpuidle(void) { }
 166static inline bool cpuidle_not_available(struct cpuidle_driver *drv,
 167                                         struct cpuidle_device *dev)
 168{return true; }
 169static inline int cpuidle_select(struct cpuidle_driver *drv,
 170                                 struct cpuidle_device *dev, bool *stop_tick)
 171{return -ENODEV; }
 172static inline int cpuidle_enter(struct cpuidle_driver *drv,
 173                                struct cpuidle_device *dev, int index)
 174{return -ENODEV; }
 175static inline void cpuidle_reflect(struct cpuidle_device *dev, int index) { }
 176static inline u64 cpuidle_poll_time(struct cpuidle_driver *drv,
 177                             struct cpuidle_device *dev)
 178{return 0; }
 179static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 180{return -ENODEV; }
 181static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
 182static inline struct cpuidle_driver *cpuidle_driver_ref(void) {return NULL; }
 183static inline void cpuidle_driver_unref(void) {}
 184static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 185static inline int cpuidle_register_device(struct cpuidle_device *dev)
 186{return -ENODEV; }
 187static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 188static inline int cpuidle_register(struct cpuidle_driver *drv,
 189                                   const struct cpumask *const coupled_cpus)
 190{return -ENODEV; }
 191static inline void cpuidle_unregister(struct cpuidle_driver *drv) { }
 192static inline void cpuidle_pause_and_lock(void) { }
 193static inline void cpuidle_resume_and_unlock(void) { }
 194static inline void cpuidle_pause(void) { }
 195static inline void cpuidle_resume(void) { }
 196static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 197{return -ENODEV; }
 198static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 199static inline int cpuidle_play_dead(void) {return -ENODEV; }
 200static inline struct cpuidle_driver *cpuidle_get_cpu_driver(
 201        struct cpuidle_device *dev) {return NULL; }
 202static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; }
 203#endif
 204
 205#ifdef CONFIG_CPU_IDLE
 206extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
 207                                      struct cpuidle_device *dev);
 208extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
 209                                struct cpuidle_device *dev);
 210extern void cpuidle_use_deepest_state(bool enable);
 211#else
 212static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
 213                                             struct cpuidle_device *dev)
 214{return -ENODEV; }
 215static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
 216                                       struct cpuidle_device *dev)
 217{return -ENODEV; }
 218static inline void cpuidle_use_deepest_state(bool enable)
 219{
 220}
 221#endif
 222
 223/* kernel/sched/idle.c */
 224extern void sched_idle_set_state(struct cpuidle_state *idle_state);
 225extern void default_idle_call(void);
 226
 227#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
 228void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a);
 229#else
 230static inline void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a)
 231{
 232}
 233#endif
 234
 235#if defined(CONFIG_CPU_IDLE) && defined(CONFIG_ARCH_HAS_CPU_RELAX)
 236void cpuidle_poll_state_init(struct cpuidle_driver *drv);
 237#else
 238static inline void cpuidle_poll_state_init(struct cpuidle_driver *drv) {}
 239#endif
 240
 241/******************************
 242 * CPUIDLE GOVERNOR INTERFACE *
 243 ******************************/
 244
 245struct cpuidle_governor {
 246        char                    name[CPUIDLE_NAME_LEN];
 247        struct list_head        governor_list;
 248        unsigned int            rating;
 249
 250        int  (*enable)          (struct cpuidle_driver *drv,
 251                                        struct cpuidle_device *dev);
 252        void (*disable)         (struct cpuidle_driver *drv,
 253                                        struct cpuidle_device *dev);
 254
 255        int  (*select)          (struct cpuidle_driver *drv,
 256                                        struct cpuidle_device *dev,
 257                                        bool *stop_tick);
 258        void (*reflect)         (struct cpuidle_device *dev, int index);
 259};
 260
 261#ifdef CONFIG_CPU_IDLE
 262extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 263extern int cpuidle_governor_latency_req(unsigned int cpu);
 264#else
 265static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 266{return 0;}
 267#endif
 268
 269#define __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter,                   \
 270                                idx,                                    \
 271                                state,                                  \
 272                                is_retention)                           \
 273({                                                                      \
 274        int __ret = 0;                                                  \
 275                                                                        \
 276        if (!idx) {                                                     \
 277                cpu_do_idle();                                          \
 278                return idx;                                             \
 279        }                                                               \
 280                                                                        \
 281        if (!is_retention)                                              \
 282                __ret =  cpu_pm_enter();                                \
 283        if (!__ret) {                                                   \
 284                __ret = low_level_idle_enter(state);                    \
 285                if (!is_retention)                                      \
 286                        cpu_pm_exit();                                  \
 287        }                                                               \
 288                                                                        \
 289        __ret ? -1 : idx;                                               \
 290})
 291
 292#define CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx)        \
 293        __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, idx, 0)
 294
 295#define CPU_PM_CPU_IDLE_ENTER_RETENTION(low_level_idle_enter, idx)      \
 296        __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, idx, 1)
 297
 298#define CPU_PM_CPU_IDLE_ENTER_PARAM(low_level_idle_enter, idx, state)   \
 299        __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, state, 0)
 300
 301#define CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(low_level_idle_enter, idx, state) \
 302        __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, state, 1)
 303
 304#endif /* _LINUX_CPUIDLE_H */
 305
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