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 #include <linux/context_tracking.h>
  18
  19 #define CPUIDLE_STATE_MAX       10
  20 #define CPUIDLE_NAME_LEN        16
  21 #define CPUIDLE_DESC_LEN        32
  22
  23 struct module;
  24
  25 struct cpuidle_device;
  26 struct cpuidle_driver;
  27
  28
  29 /****************************
  30  * CPUIDLE DEVICE INTERFACE *
  31  ****************************/
  32
  33 #define CPUIDLE_STATE_DISABLED_BY_USER          BIT(0)
  34 #define CPUIDLE_STATE_DISABLED_BY_DRIVER        BIT(1)
  35
  36 struct cpuidle_state_usage {
  37         unsigned long long      disable;
  38         unsigned long long      usage;
  39         u64                     time_ns;
  40         unsigned long long      above; /* Number of times it's been too deep */
  41         unsigned long long      below; /* Number of times it's been too shallow */
  42         unsigned long long      rejected; /* Number of times idle entry was rejected */
  43 #ifdef CONFIG_SUSPEND
  44         unsigned long long      s2idle_usage;
  45         unsigned long long      s2idle_time; /* in US */
  46 #endif
  47 };
  48
  49 struct cpuidle_state {
  50         char            name[CPUIDLE_NAME_LEN];
  51         char            desc[CPUIDLE_DESC_LEN];
  52
  53         s64             exit_latency_ns;
  54         s64             target_residency_ns;
  55         unsigned int    flags;
  56         unsigned int    exit_latency; /* in US */
  57         int             power_usage; /* in mW */
  58         unsigned int    target_residency; /* in US */
  59
  60         int (*enter)    (struct cpuidle_device *dev,
  61                         struct cpuidle_driver *drv,
  62                         int index);
  63
  64         int (*enter_dead) (struct cpuidle_device *dev, int index);
  65
  66         /*
  67          * CPUs execute ->enter_s2idle with the local tick or entire timekeeping
  68          * suspended, so it must not re-enable interrupts at any point (even
  69          * temporarily) or attempt to change states of clock event devices.
  70          *
  71          * This callback may point to the same function as ->enter if all of
  72          * the above requirements are met by it.
  73          */
  74         int (*enter_s2idle)(struct cpuidle_device *dev,
  75                             struct cpuidle_driver *drv,
  76                             int index);
  77 };
  78
  79 /* Idle State Flags */
  80 #define CPUIDLE_FLAG_NONE               (0x00)
  81 #define CPUIDLE_FLAG_POLLING            BIT(0) /* polling state */
  82 #define CPUIDLE_FLAG_COUPLED            BIT(1) /* state applies to multiple cpus */
  83 #define CPUIDLE_FLAG_TIMER_STOP         BIT(2) /* timer is stopped on this state */
  84 #define CPUIDLE_FLAG_UNUSABLE           BIT(3) /* avoid using this state */
  85 #define CPUIDLE_FLAG_OFF                BIT(4) /* disable this state by default */
  86 #define CPUIDLE_FLAG_TLB_FLUSHED        BIT(5) /* idle-state flushes TLBs */
  87 #define CPUIDLE_FLAG_RCU_IDLE           BIT(6) /* idle-state takes care of RCU */
  88
  89 struct cpuidle_device_kobj;
  90 struct cpuidle_state_kobj;
  91 struct cpuidle_driver_kobj;
  92
  93 struct cpuidle_device {
  94         unsigned int            registered:1;
  95         unsigned int            enabled:1;
  96         unsigned int            poll_time_limit:1;
  97         unsigned int            cpu;
  98         ktime_t                 next_hrtimer;
  99
 100         int                     last_state_idx;
 101         u64                     last_residency_ns;
 102         u64                     poll_limit_ns;
 103         u64                     forced_idle_latency_limit_ns;
 104         struct cpuidle_state_usage      states_usage[CPUIDLE_STATE_MAX];
 105         struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
 106         struct cpuidle_driver_kobj *kobj_driver;
 107         struct cpuidle_device_kobj *kobj_dev;
 108         struct list_head        device_list;
 109
 110 #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
 111         cpumask_t               coupled_cpus;
 112         struct cpuidle_coupled  *coupled;
 113 #endif
 114 };
 115
 116 DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
 117 DECLARE_PER_CPU(struct cpuidle_device, cpuidle_dev);
 118
 119 static __always_inline void ct_cpuidle_enter(void)
 120 {
 121         lockdep_assert_irqs_disabled();
 122         /*
 123          * Idle is allowed to (temporary) enable IRQs. It
 124          * will return with IRQs disabled.
 125          *
 126          * Trace IRQs enable here, then switch off RCU, and have
 127          * arch_cpu_idle() use raw_local_irq_enable(). Note that
 128          * ct_idle_enter() relies on lockdep IRQ state, so switch that
 129          * last -- this is very similar to the entry code.
 130          */
 131         trace_hardirqs_on_prepare();
 132         lockdep_hardirqs_on_prepare();
 133         instrumentation_end();
 134         ct_idle_enter();
 135         lockdep_hardirqs_on(_RET_IP_);
 136 }
 137
 138 static __always_inline void ct_cpuidle_exit(void)
 139 {
 140         /*
 141          * Carefully undo the above.
 142          */
 143         lockdep_hardirqs_off(_RET_IP_);
 144         ct_idle_exit();
 145         instrumentation_begin();
 146 }
 147
 148 /****************************
 149  * CPUIDLE DRIVER INTERFACE *
 150  ****************************/
 151
 152 struct cpuidle_driver {
 153         const char              *name;
 154         struct module           *owner;
 155
 156         /* used by the cpuidle framework to setup the broadcast timer */
 157         unsigned int            bctimer:1;
 158         /* states array must be ordered in decreasing power consumption */
 159         struct cpuidle_state    states[CPUIDLE_STATE_MAX];
 160         int                     state_count;
 161         int                     safe_state_index;
 162
 163         /* the driver handles the cpus in cpumask */
 164         struct cpumask          *cpumask;
 165
 166         /* preferred governor to switch at register time */
 167         const char              *governor;
 168 };
 169
 170 #ifdef CONFIG_CPU_IDLE
 171 extern void disable_cpuidle(void);
 172 extern bool cpuidle_not_available(struct cpuidle_driver *drv,
 173                                   struct cpuidle_device *dev);
 174
 175 extern int cpuidle_select(struct cpuidle_driver *drv,
 176                           struct cpuidle_device *dev,
 177                           bool *stop_tick);
 178 extern int cpuidle_enter(struct cpuidle_driver *drv,
 179                          struct cpuidle_device *dev, int index);
 180 extern void cpuidle_reflect(struct cpuidle_device *dev, int index);
 181 extern u64 cpuidle_poll_time(struct cpuidle_driver *drv,
 182                              struct cpuidle_device *dev);
 183
 184 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 185 extern struct cpuidle_driver *cpuidle_get_driver(void);
 186 extern void cpuidle_driver_state_disabled(struct cpuidle_driver *drv, int idx,
 187                                         bool disable);
 188 extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 189 extern int cpuidle_register_device(struct cpuidle_device *dev);
 190 extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 191 extern int cpuidle_register(struct cpuidle_driver *drv,
 192                             const struct cpumask *const coupled_cpus);
 193 extern void cpuidle_unregister(struct cpuidle_driver *drv);
 194 extern void cpuidle_pause_and_lock(void);
 195 extern void cpuidle_resume_and_unlock(void);
 196 extern void cpuidle_pause(void);
 197 extern void cpuidle_resume(void);
 198 extern int cpuidle_enable_device(struct cpuidle_device *dev);
 199 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 200 extern int cpuidle_play_dead(void);
 201
 202 extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
 203 static inline struct cpuidle_device *cpuidle_get_device(void)
 204 {return __this_cpu_read(cpuidle_devices); }
 205 #else
 206 static inline void disable_cpuidle(void) { }
 207 static inline bool cpuidle_not_available(struct cpuidle_driver *drv,
 208                                          struct cpuidle_device *dev)
 209 {return true; }
 210 static inline int cpuidle_select(struct cpuidle_driver *drv,
 211                                  struct cpuidle_device *dev, bool *stop_tick)
 212 {return -ENODEV; }
 213 static inline int cpuidle_enter(struct cpuidle_driver *drv,
 214                                 struct cpuidle_device *dev, int index)
 215 {return -ENODEV; }
 216 static inline void cpuidle_reflect(struct cpuidle_device *dev, int index) { }
 217 static inline u64 cpuidle_poll_time(struct cpuidle_driver *drv,
 218                              struct cpuidle_device *dev)
 219 {return 0; }
 220 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 221 {return -ENODEV; }
 222 static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
 223 static inline void cpuidle_driver_state_disabled(struct cpuidle_driver *drv,
 224                                                int idx, bool disable) { }
 225 static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 226 static inline int cpuidle_register_device(struct cpuidle_device *dev)
 227 {return -ENODEV; }
 228 static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 229 static inline int cpuidle_register(struct cpuidle_driver *drv,
 230                                    const struct cpumask *const coupled_cpus)
 231 {return -ENODEV; }
 232 static inline void cpuidle_unregister(struct cpuidle_driver *drv) { }
 233 static inline void cpuidle_pause_and_lock(void) { }
 234 static inline void cpuidle_resume_and_unlock(void) { }
 235 static inline void cpuidle_pause(void) { }
 236 static inline void cpuidle_resume(void) { }
 237 static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 238 {return -ENODEV; }
 239 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 240 static inline int cpuidle_play_dead(void) {return -ENODEV; }
 241 static inline struct cpuidle_driver *cpuidle_get_cpu_driver(
 242         struct cpuidle_device *dev) {return NULL; }
 243 static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; }
 244 #endif
 245
 246 #ifdef CONFIG_CPU_IDLE
 247 extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
 248                                       struct cpuidle_device *dev,
 249                                       u64 latency_limit_ns);
 250 extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
 251                                 struct cpuidle_device *dev);
 252 extern void cpuidle_use_deepest_state(u64 latency_limit_ns);
 253 #else
 254 static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
 255                                              struct cpuidle_device *dev,
 256                                              u64 latency_limit_ns)
 257 {return -ENODEV; }
 258 static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
 259                                        struct cpuidle_device *dev)
 260 {return -ENODEV; }
 261 static inline void cpuidle_use_deepest_state(u64 latency_limit_ns)
 262 {
 263 }
 264 #endif
 265
 266 /* kernel/sched/idle.c */
 267 extern void sched_idle_set_state(struct cpuidle_state *idle_state);
 268 extern void default_idle_call(void);
 269
 270 #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
 271 void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a);
 272 #else
 273 static inline void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a)
 274 {
 275 }
 276 #endif
 277
 278 #if defined(CONFIG_CPU_IDLE) && defined(CONFIG_ARCH_HAS_CPU_RELAX)
 279 void cpuidle_poll_state_init(struct cpuidle_driver *drv);
 280 #else
 281 static inline void cpuidle_poll_state_init(struct cpuidle_driver *drv) {}
 282 #endif
 283
 284 /******************************
 285  * CPUIDLE GOVERNOR INTERFACE *
 286  ******************************/
 287
 288 struct cpuidle_governor {
 289         char                    name[CPUIDLE_NAME_LEN];
 290         struct list_head        governor_list;
 291         unsigned int            rating;
 292
 293         int  (*enable)          (struct cpuidle_driver *drv,
 294                                         struct cpuidle_device *dev);
 295         void (*disable)         (struct cpuidle_driver *drv,
 296                                         struct cpuidle_device *dev);
 297
 298         int  (*select)          (struct cpuidle_driver *drv,
 299                                         struct cpuidle_device *dev,
 300                                         bool *stop_tick);
 301         void (*reflect)         (struct cpuidle_device *dev, int index);
 302 };
 303
 304 extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 305 extern s64 cpuidle_governor_latency_req(unsigned int cpu);
 306
 307 #define __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter,                   \
 308                                 idx,                                    \
 309                                 state,                                  \
 310                                 is_retention, is_rcu)                   \
 311 ({                                                                      \
 312         int __ret = 0;                                                  \
 313                                                                         \
 314         if (!idx) {                                                     \
 315                 cpu_do_idle();                                          \
 316                 return idx;                                             \
 317         }                                                               \
 318                                                                         \
 319         if (!is_retention)                                              \
 320                 __ret =  cpu_pm_enter();                                \
 321         if (!__ret) {                                                   \
 322                 if (!is_rcu)                                            \
 323                         ct_cpuidle_enter();                             \
 324                 __ret = low_level_idle_enter(state);                    \
 325                 if (!is_rcu)                                            \
 326                         ct_cpuidle_exit();                              \
 327                 if (!is_retention)                                      \
 328                         cpu_pm_exit();                                  \
 329         }                                                               \
 330                                                                         \
 331         __ret ? -1 : idx;                                               \
 332 })
 333
 334 #define CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx)        \
 335         __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, idx, 0, 0)
 336
 337 #define CPU_PM_CPU_IDLE_ENTER_RETENTION(low_level_idle_enter, idx)      \
 338         __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, idx, 1, 0)
 339
 340 #define CPU_PM_CPU_IDLE_ENTER_PARAM(low_level_idle_enter, idx, state)   \
 341         __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, state, 0, 0)
 342
 343 #define CPU_PM_CPU_IDLE_ENTER_PARAM_RCU(low_level_idle_enter, idx, state)       \
 344         __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, state, 0, 1)
 345
 346 #define CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(low_level_idle_enter, idx, state) \
 347         __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, state, 1, 0)
 348
 349 #define CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM_RCU(low_level_idle_enter, idx, state)     \
 350         __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, state, 1, 1)
 351
 352 #endif /* _LINUX_CPUIDLE_H */