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#ifdef CONFIG_SUSPEND
  37        unsigned long long      s2idle_usage;
  38        unsigned long long      s2idle_time; /* in US */
  39#endif
  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         * CPUs execute ->enter_s2idle with the local tick or entire timekeeping
  60         * suspended, so it must not re-enable interrupts at any point (even
  61         * temporarily) or attempt to change states of clock event devices.
  62         */
  63        void (*enter_s2idle) (struct cpuidle_device *dev,
  64                              struct cpuidle_driver *drv,
  65                              int index);
  66};
  67
  68/* Idle State Flags */
  69#define CPUIDLE_FLAG_NONE       (0x00)
  70#define CPUIDLE_FLAG_POLLING    (0x01) /* polling state */
  71#define CPUIDLE_FLAG_COUPLED    (0x02) /* state applies to multiple cpus */
  72#define CPUIDLE_FLAG_TIMER_STOP (0x04)  /* timer is stopped on this state */
  73
  74#define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
  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            cpu;
  85
  86        int                     last_residency;
  87        struct cpuidle_state_usage      states_usage[CPUIDLE_STATE_MAX];
  88        struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
  89        struct cpuidle_driver_kobj *kobj_driver;
  90        struct cpuidle_device_kobj *kobj_dev;
  91        struct list_head        device_list;
  92
  93#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
  94        cpumask_t               coupled_cpus;
  95        struct cpuidle_coupled  *coupled;
  96#endif
  97};
  98
  99DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
 100DECLARE_PER_CPU(struct cpuidle_device, cpuidle_dev);
 101
 102/**
 103 * cpuidle_get_last_residency - retrieves the last state's residency time
 104 * @dev: the target CPU
 105 */
 106static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
 107{
 108        return dev->last_residency;
 109}
 110
 111
 112/****************************
 113 * CPUIDLE DRIVER INTERFACE *
 114 ****************************/
 115
 116struct cpuidle_driver {
 117        const char              *name;
 118        struct module           *owner;
 119        int                     refcnt;
 120
 121        /* used by the cpuidle framework to setup the broadcast timer */
 122        unsigned int            bctimer:1;
 123        /* states array must be ordered in decreasing power consumption */
 124        struct cpuidle_state    states[CPUIDLE_STATE_MAX];
 125        int                     state_count;
 126        int                     safe_state_index;
 127
 128        /* the driver handles the cpus in cpumask */
 129        struct cpumask          *cpumask;
 130};
 131
 132#ifdef CONFIG_CPU_IDLE
 133extern void disable_cpuidle(void);
 134extern bool cpuidle_not_available(struct cpuidle_driver *drv,
 135                                  struct cpuidle_device *dev);
 136
 137extern int cpuidle_select(struct cpuidle_driver *drv,
 138                          struct cpuidle_device *dev,
 139                          bool *stop_tick);
 140extern int cpuidle_enter(struct cpuidle_driver *drv,
 141                         struct cpuidle_device *dev, int index);
 142extern void cpuidle_reflect(struct cpuidle_device *dev, int index);
 143
 144extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 145extern struct cpuidle_driver *cpuidle_get_driver(void);
 146extern struct cpuidle_driver *cpuidle_driver_ref(void);
 147extern void cpuidle_driver_unref(void);
 148extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 149extern int cpuidle_register_device(struct cpuidle_device *dev);
 150extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 151extern int cpuidle_register(struct cpuidle_driver *drv,
 152                            const struct cpumask *const coupled_cpus);
 153extern void cpuidle_unregister(struct cpuidle_driver *drv);
 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_play_dead(void);
 161
 162extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
 163static inline struct cpuidle_device *cpuidle_get_device(void)
 164{return __this_cpu_read(cpuidle_devices); }
 165#else
 166static inline void disable_cpuidle(void) { }
 167static inline bool cpuidle_not_available(struct cpuidle_driver *drv,
 168                                         struct cpuidle_device *dev)
 169{return true; }
 170static inline int cpuidle_select(struct cpuidle_driver *drv,
 171                                 struct cpuidle_device *dev, bool *stop_tick)
 172{return -ENODEV; }
 173static inline int cpuidle_enter(struct cpuidle_driver *drv,
 174                                struct cpuidle_device *dev, int index)
 175{return -ENODEV; }
 176static inline void cpuidle_reflect(struct cpuidle_device *dev, int index) { }
 177static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 178{return -ENODEV; }
 179static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
 180static inline struct cpuidle_driver *cpuidle_driver_ref(void) {return NULL; }
 181static inline void cpuidle_driver_unref(void) {}
 182static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 183static inline int cpuidle_register_device(struct cpuidle_device *dev)
 184{return -ENODEV; }
 185static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 186static inline int cpuidle_register(struct cpuidle_driver *drv,
 187                                   const struct cpumask *const coupled_cpus)
 188{return -ENODEV; }
 189static inline void cpuidle_unregister(struct cpuidle_driver *drv) { }
 190static inline void cpuidle_pause_and_lock(void) { }
 191static inline void cpuidle_resume_and_unlock(void) { }
 192static inline void cpuidle_pause(void) { }
 193static inline void cpuidle_resume(void) { }
 194static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 195{return -ENODEV; }
 196static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 197static inline int cpuidle_play_dead(void) {return -ENODEV; }
 198static inline struct cpuidle_driver *cpuidle_get_cpu_driver(
 199        struct cpuidle_device *dev) {return NULL; }
 200static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; }
 201#endif
 202
 203#ifdef CONFIG_CPU_IDLE
 204extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
 205                                      struct cpuidle_device *dev);
 206extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
 207                                struct cpuidle_device *dev);
 208extern void cpuidle_use_deepest_state(bool enable);
 209#else
 210static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
 211                                             struct cpuidle_device *dev)
 212{return -ENODEV; }
 213static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
 214                                       struct cpuidle_device *dev)
 215{return -ENODEV; }
 216static inline void cpuidle_use_deepest_state(bool enable)
 217{
 218}
 219#endif
 220
 221/* kernel/sched/idle.c */
 222extern void sched_idle_set_state(struct cpuidle_state *idle_state);
 223extern void default_idle_call(void);
 224
 225#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
 226void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a);
 227#else
 228static inline void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a)
 229{
 230}
 231#endif
 232
 233#if defined(CONFIG_CPU_IDLE) && defined(CONFIG_ARCH_HAS_CPU_RELAX)
 234void cpuidle_poll_state_init(struct cpuidle_driver *drv);
 235#else
 236static inline void cpuidle_poll_state_init(struct cpuidle_driver *drv) {}
 237#endif
 238
 239/******************************
 240 * CPUIDLE GOVERNOR INTERFACE *
 241 ******************************/
 242
 243struct cpuidle_governor {
 244        char                    name[CPUIDLE_NAME_LEN];
 245        struct list_head        governor_list;
 246        unsigned int            rating;
 247
 248        int  (*enable)          (struct cpuidle_driver *drv,
 249                                        struct cpuidle_device *dev);
 250        void (*disable)         (struct cpuidle_driver *drv,
 251                                        struct cpuidle_device *dev);
 252
 253        int  (*select)          (struct cpuidle_driver *drv,
 254                                        struct cpuidle_device *dev,
 255                                        bool *stop_tick);
 256        void (*reflect)         (struct cpuidle_device *dev, int index);
 257};
 258
 259#ifdef CONFIG_CPU_IDLE
 260extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 261#else
 262static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 263{return 0;}
 264#endif
 265
 266#define __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, is_retention) \
 267({                                                                      \
 268        int __ret = 0;                                                  \
 269                                                                        \
 270        if (!idx) {                                                     \
 271                cpu_do_idle();                                          \
 272                return idx;                                             \
 273        }                                                               \
 274                                                                        \
 275        if (!is_retention)                                              \
 276                __ret =  cpu_pm_enter();                                \
 277        if (!__ret) {                                                   \
 278                __ret = low_level_idle_enter(idx);                      \
 279                if (!is_retention)                                      \
 280                        cpu_pm_exit();                                  \
 281        }                                                               \
 282                                                                        \
 283        __ret ? -1 : idx;                                               \
 284})
 285
 286#define CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx)        \
 287        __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, 0)
 288
 289#define CPU_PM_CPU_IDLE_ENTER_RETENTION(low_level_idle_enter, idx)      \
 290        __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, 1)
 291
 292#endif /* _LINUX_CPUIDLE_H */
 293
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