include/linux/cpuidle.h

   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
  22 struct module;
  23
  24 struct cpuidle_device;
  25 struct cpuidle_driver;
  26
  27
  28 /****************************
  29  * CPUIDLE DEVICE INTERFACE *
  30  ****************************/
  31
  32 #define CPUIDLE_STATE_DISABLED_BY_USER          BIT(0)
  33 #define CPUIDLE_STATE_DISABLED_BY_DRIVER        BIT(1)
  34
  35 struct cpuidle_state_usage {
  36         unsigned long long      disable;
  37         unsigned long long      usage;
  38         u64                     time_ns;
  39         unsigned long long      above; /* Number of times it's been too deep */
  40         unsigned long long      below; /* Number of times it's been too shallow */
  41 #ifdef CONFIG_SUSPEND
  42         unsigned long long      s2idle_usage;
  43         unsigned long long      s2idle_time; /* in US */
  44 #endif
  45 };
  46
  47 struct cpuidle_state {
  48         char            name[CPUIDLE_NAME_LEN];
  49         char            desc[CPUIDLE_DESC_LEN];
  50
  51         u64             exit_latency_ns;
  52         u64             target_residency_ns;
  53         unsigned int    flags;
  54         unsigned int    exit_latency; /* in US */
  55         int             power_usage; /* in mW */
  56         unsigned int    target_residency; /* in US */
  57
  58         int (*enter)    (struct cpuidle_device *dev,
  59                         struct cpuidle_driver *drv,
  60                         int index);
  61
  62         int (*enter_dead) (struct cpuidle_device *dev, int index);
  63
  64         /*
  65          * CPUs execute ->enter_s2idle with the local tick or entire timekeeping
  66          * suspended, so it must not re-enable interrupts at any point (even
  67          * temporarily) or attempt to change states of clock event devices.
  68          *
  69          * This callback may point to the same function as ->enter if all of
  70          * the above requirements are met by it.
  71          */
  72         int (*enter_s2idle)(struct cpuidle_device *dev,
  73                             struct cpuidle_driver *drv,
  74                             int index);
  75 };
  76
  77 /* Idle State Flags */
  78 #define CPUIDLE_FLAG_NONE       (0x00)
  79 #define CPUIDLE_FLAG_POLLING    BIT(0) /* polling state */
  80 #define CPUIDLE_FLAG_COUPLED    BIT(1) /* state applies to multiple cpus */
  81 #define CPUIDLE_FLAG_TIMER_STOP BIT(2) /* timer is stopped on this state */
  82 #define CPUIDLE_FLAG_UNUSABLE   BIT(3) /* avoid using this state */
  83 #define CPUIDLE_FLAG_OFF        BIT(4) /* disable this state by default */
  84
  85 struct cpuidle_device_kobj;
  86 struct cpuidle_state_kobj;
  87 struct cpuidle_driver_kobj;
  88
  89 struct cpuidle_device {
  90         unsigned int            registered:1;
  91         unsigned int            enabled:1;
  92         unsigned int            poll_time_limit:1;
  93         unsigned int            cpu;
  94         ktime_t                 next_hrtimer;
  95
  96         int                     last_state_idx;
  97         u64                     last_residency_ns;
  98         u64                     poll_limit_ns;
  99         u64                     forced_idle_latency_limit_ns;
 100         struct cpuidle_state_usage      states_usage[CPUIDLE_STATE_MAX];
 101         struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
 102         struct cpuidle_driver_kobj *kobj_driver;
 103         struct cpuidle_device_kobj *kobj_dev;
 104         struct list_head        device_list;
 105
 106 #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
 107         cpumask_t               coupled_cpus;
 108         struct cpuidle_coupled  *coupled;
 109 #endif
 110 };
 111
 112 DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
 113 DECLARE_PER_CPU(struct cpuidle_device, cpuidle_dev);
 114
 115 /****************************
 116  * CPUIDLE DRIVER INTERFACE *
 117  ****************************/
 118
 119 struct cpuidle_driver {
 120         const char              *name;
 121         struct module           *owner;
 122
 123         /* used by the cpuidle framework to setup the broadcast timer */
 124         unsigned int            bctimer:1;
 125         /* states array must be ordered in decreasing power consumption */
 126         struct cpuidle_state    states[CPUIDLE_STATE_MAX];
 127         int                     state_count;
 128         int                     safe_state_index;
 129
 130         /* the driver handles the cpus in cpumask */
 131         struct cpumask          *cpumask;
 132
 133         /* preferred governor to switch at register time */
 134         const char              *governor;
 135 };
 136
 137 #ifdef CONFIG_CPU_IDLE
 138 extern void disable_cpuidle(void);
 139 extern bool cpuidle_not_available(struct cpuidle_driver *drv,
 140                                   struct cpuidle_device *dev);
 141
 142 extern int cpuidle_select(struct cpuidle_driver *drv,
 143                           struct cpuidle_device *dev,
 144                           bool *stop_tick);
 145 extern int cpuidle_enter(struct cpuidle_driver *drv,
 146                          struct cpuidle_device *dev, int index);
 147 extern void cpuidle_reflect(struct cpuidle_device *dev, int index);
 148 extern u64 cpuidle_poll_time(struct cpuidle_driver *drv,
 149                              struct cpuidle_device *dev);
 150
 151 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 152 extern struct cpuidle_driver *cpuidle_get_driver(void);
 153 extern void cpuidle_driver_state_disabled(struct cpuidle_driver *drv, int idx,
 154                                         bool disable);
 155 extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 156 extern int cpuidle_register_device(struct cpuidle_device *dev);
 157 extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 158 extern int cpuidle_register(struct cpuidle_driver *drv,
 159                             const struct cpumask *const coupled_cpus);
 160 extern void cpuidle_unregister(struct cpuidle_driver *drv);
 161 extern void cpuidle_pause_and_lock(void);
 162 extern void cpuidle_resume_and_unlock(void);
 163 extern void cpuidle_pause(void);
 164 extern void cpuidle_resume(void);
 165 extern int cpuidle_enable_device(struct cpuidle_device *dev);
 166 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 167 extern int cpuidle_play_dead(void);
 168
 169 extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
 170 static inline struct cpuidle_device *cpuidle_get_device(void)
 171 {return __this_cpu_read(cpuidle_devices); }
 172 #else
 173 static inline void disable_cpuidle(void) { }
 174 static inline bool cpuidle_not_available(struct cpuidle_driver *drv,
 175                                          struct cpuidle_device *dev)
 176 {return true; }
 177 static inline int cpuidle_select(struct cpuidle_driver *drv,
 178                                  struct cpuidle_device *dev, bool *stop_tick)
 179 {return -ENODEV; }
 180 static inline int cpuidle_enter(struct cpuidle_driver *drv,
 181                                 struct cpuidle_device *dev, int index)
 182 {return -ENODEV; }
 183 static inline void cpuidle_reflect(struct cpuidle_device *dev, int index) { }
 184 static inline u64 cpuidle_poll_time(struct cpuidle_driver *drv,
 185                              struct cpuidle_device *dev)
 186 {return 0; }
 187 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 188 {return -ENODEV; }
 189 static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
 190 static inline void cpuidle_driver_state_disabled(struct cpuidle_driver *drv,
 191                                                int idx, bool disable) { }
 192 static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 193 static inline int cpuidle_register_device(struct cpuidle_device *dev)
 194 {return -ENODEV; }
 195 static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 196 static inline int cpuidle_register(struct cpuidle_driver *drv,
 197                                    const struct cpumask *const coupled_cpus)
 198 {return -ENODEV; }
 199 static inline void cpuidle_unregister(struct cpuidle_driver *drv) { }
 200 static inline void cpuidle_pause_and_lock(void) { }
 201 static inline void cpuidle_resume_and_unlock(void) { }
 202 static inline void cpuidle_pause(void) { }
 203 static inline void cpuidle_resume(void) { }
 204 static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 205 {return -ENODEV; }
 206 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 207 static inline int cpuidle_play_dead(void) {return -ENODEV; }
 208 static inline struct cpuidle_driver *cpuidle_get_cpu_driver(
 209         struct cpuidle_device *dev) {return NULL; }
 210 static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; }
 211 #endif
 212
 213 #ifdef CONFIG_CPU_IDLE
 214 extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
 215                                       struct cpuidle_device *dev,
 216                                       u64 latency_limit_ns);
 217 extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
 218                                 struct cpuidle_device *dev);
 219 extern void cpuidle_use_deepest_state(u64 latency_limit_ns);
 220 #else
 221 static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
 222                                              struct cpuidle_device *dev,
 223                                              u64 latency_limit_ns)
 224 {return -ENODEV; }
 225 static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
 226                                        struct cpuidle_device *dev)
 227 {return -ENODEV; }
 228 static inline void cpuidle_use_deepest_state(u64 latency_limit_ns)
 229 {
 230 }
 231 #endif
 232
 233 /* kernel/sched/idle.c */
 234 extern void sched_idle_set_state(struct cpuidle_state *idle_state);
 235 extern void default_idle_call(void);
 236
 237 #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
 238 void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a);
 239 #else
 240 static inline void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a)
 241 {
 242 }
 243 #endif
 244
 245 #if defined(CONFIG_CPU_IDLE) && defined(CONFIG_ARCH_HAS_CPU_RELAX)
 246 void cpuidle_poll_state_init(struct cpuidle_driver *drv);
 247 #else
 248 static inline void cpuidle_poll_state_init(struct cpuidle_driver *drv) {}
 249 #endif
 250
 251 /******************************
 252  * CPUIDLE GOVERNOR INTERFACE *
 253  ******************************/
 254
 255 struct cpuidle_governor {
 256         char                    name[CPUIDLE_NAME_LEN];
 257         struct list_head        governor_list;
 258         unsigned int            rating;
 259
 260         int  (*enable)          (struct cpuidle_driver *drv,
 261                                         struct cpuidle_device *dev);
 262         void (*disable)         (struct cpuidle_driver *drv,
 263                                         struct cpuidle_device *dev);
 264
 265         int  (*select)          (struct cpuidle_driver *drv,
 266                                         struct cpuidle_device *dev,
 267                                         bool *stop_tick);
 268         void (*reflect)         (struct cpuidle_device *dev, int index);
 269 };
 270
 271 #ifdef CONFIG_CPU_IDLE
 272 extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 273 extern s64 cpuidle_governor_latency_req(unsigned int cpu);
 274 #else
 275 static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 276 {return 0;}
 277 #endif
 278
 279 #define __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter,                   \
 280                                 idx,                                    \
 281                                 state,                                  \
 282                                 is_retention)                           \
 283 ({                                                                      \
 284         int __ret = 0;                                                  \
 285                                                                         \
 286         if (!idx) {                                                     \
 287                 cpu_do_idle();                                          \
 288                 return idx;                                             \
 289         }                                                               \
 290                                                                         \
 291         if (!is_retention)                                              \
 292                 __ret =  cpu_pm_enter();                                \
 293         if (!__ret) {                                                   \
 294                 __ret = low_level_idle_enter(state);                    \
 295                 if (!is_retention)                                      \
 296                         cpu_pm_exit();                                  \
 297         }                                                               \
 298                                                                         \
 299         __ret ? -1 : idx;                                               \
 300 })
 301
 302 #define CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx)        \
 303         __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, idx, 0)
 304
 305 #define CPU_PM_CPU_IDLE_ENTER_RETENTION(low_level_idle_enter, idx)      \
 306         __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, idx, 1)
 307
 308 #define CPU_PM_CPU_IDLE_ENTER_PARAM(low_level_idle_enter, idx, state)   \
 309         __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, state, 0)
 310
 311 #define CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(low_level_idle_enter, idx, state) \
 312         __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, state, 1)
 313
 314 #endif /* _LINUX_CPUIDLE_H */