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 struct cpuidle_state_usage {
  33         unsigned long long      disable;
  34         unsigned long long      usage;
  35         unsigned long long      time; /* in US */
  36 };
  37
  38 struct 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_freeze 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_freeze) (struct cpuidle_device *dev,
  60                               struct cpuidle_driver *drv,
  61                               int index);
  62 };
  63
  64 /* Idle State Flags */
  65 #define CPUIDLE_FLAG_COUPLED    (0x02) /* state applies to multiple cpus */
  66 #define CPUIDLE_FLAG_TIMER_STOP (0x04)  /* timer is stopped on this state */
  67
  68 #define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
  69
  70 struct cpuidle_device_kobj;
  71 struct cpuidle_state_kobj;
  72 struct cpuidle_driver_kobj;
  73
  74 struct cpuidle_device {
  75         unsigned int            registered:1;
  76         unsigned int            enabled:1;
  77         unsigned int            cpu;
  78
  79         int                     last_residency;
  80         int                     state_count;
  81         struct cpuidle_state_usage      states_usage[CPUIDLE_STATE_MAX];
  82         struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
  83         struct cpuidle_driver_kobj *kobj_driver;
  84         struct cpuidle_device_kobj *kobj_dev;
  85         struct list_head        device_list;
  86
  87 #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
  88         int                     safe_state_index;
  89         cpumask_t               coupled_cpus;
  90         struct cpuidle_coupled  *coupled;
  91 #endif
  92 };
  93
  94 DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
  95 DECLARE_PER_CPU(struct cpuidle_device, cpuidle_dev);
  96
  97 /**
  98  * cpuidle_get_last_residency - retrieves the last state's residency time
  99  * @dev: the target CPU
 100  */
 101 static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
 102 {
 103         return dev->last_residency;
 104 }
 105
 106
 107 /****************************
 108  * CPUIDLE DRIVER INTERFACE *
 109  ****************************/
 110
 111 struct cpuidle_driver {
 112         const char              *name;
 113         struct module           *owner;
 114         int                     refcnt;
 115
 116         /* used by the cpuidle framework to setup the broadcast timer */
 117         unsigned int            bctimer:1;
 118         /* states array must be ordered in decreasing power consumption */
 119         struct cpuidle_state    states[CPUIDLE_STATE_MAX];
 120         int                     state_count;
 121         int                     safe_state_index;
 122
 123         /* the driver handles the cpus in cpumask */
 124         struct cpumask          *cpumask;
 125 };
 126
 127 #ifdef CONFIG_CPU_IDLE
 128 extern void disable_cpuidle(void);
 129
 130 extern int cpuidle_select(struct cpuidle_driver *drv,
 131                           struct cpuidle_device *dev);
 132 extern int cpuidle_enter(struct cpuidle_driver *drv,
 133                          struct cpuidle_device *dev, int index);
 134 extern void cpuidle_reflect(struct cpuidle_device *dev, int index);
 135
 136 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 137 extern struct cpuidle_driver *cpuidle_get_driver(void);
 138 extern struct cpuidle_driver *cpuidle_driver_ref(void);
 139 extern void cpuidle_driver_unref(void);
 140 extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 141 extern int cpuidle_register_device(struct cpuidle_device *dev);
 142 extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 143 extern int cpuidle_register(struct cpuidle_driver *drv,
 144                             const struct cpumask *const coupled_cpus);
 145 extern void cpuidle_unregister(struct cpuidle_driver *drv);
 146 extern void cpuidle_pause_and_lock(void);
 147 extern void cpuidle_resume_and_unlock(void);
 148 extern void cpuidle_pause(void);
 149 extern void cpuidle_resume(void);
 150 extern int cpuidle_enable_device(struct cpuidle_device *dev);
 151 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 152 extern int cpuidle_play_dead(void);
 153 extern void cpuidle_enter_freeze(void);
 154
 155 extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
 156 #else
 157 static inline void disable_cpuidle(void) { }
 158 static inline int cpuidle_select(struct cpuidle_driver *drv,
 159                                  struct cpuidle_device *dev)
 160 {return -ENODEV; }
 161 static inline int cpuidle_enter(struct cpuidle_driver *drv,
 162                                 struct cpuidle_device *dev, int index)
 163 {return -ENODEV; }
 164 static inline void cpuidle_reflect(struct cpuidle_device *dev, int index) { }
 165 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 166 {return -ENODEV; }
 167 static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
 168 static inline struct cpuidle_driver *cpuidle_driver_ref(void) {return NULL; }
 169 static inline void cpuidle_driver_unref(void) {}
 170 static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 171 static inline int cpuidle_register_device(struct cpuidle_device *dev)
 172 {return -ENODEV; }
 173 static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 174 static inline int cpuidle_register(struct cpuidle_driver *drv,
 175                                    const struct cpumask *const coupled_cpus)
 176 {return -ENODEV; }
 177 static inline void cpuidle_unregister(struct cpuidle_driver *drv) { }
 178 static inline void cpuidle_pause_and_lock(void) { }
 179 static inline void cpuidle_resume_and_unlock(void) { }
 180 static inline void cpuidle_pause(void) { }
 181 static inline void cpuidle_resume(void) { }
 182 static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 183 {return -ENODEV; }
 184 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 185 static inline int cpuidle_play_dead(void) {return -ENODEV; }
 186 static inline void cpuidle_enter_freeze(void) { }
 187 static inline struct cpuidle_driver *cpuidle_get_cpu_driver(
 188         struct cpuidle_device *dev) {return NULL; }
 189 #endif
 190
 191 #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
 192 void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a);
 193 #else
 194 static inline void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a)
 195 {
 196 }
 197 #endif
 198
 199 /******************************
 200  * CPUIDLE GOVERNOR INTERFACE *
 201  ******************************/
 202
 203 struct cpuidle_governor {
 204         char                    name[CPUIDLE_NAME_LEN];
 205         struct list_head        governor_list;
 206         unsigned int            rating;
 207
 208         int  (*enable)          (struct cpuidle_driver *drv,
 209                                         struct cpuidle_device *dev);
 210         void (*disable)         (struct cpuidle_driver *drv,
 211                                         struct cpuidle_device *dev);
 212
 213         int  (*select)          (struct cpuidle_driver *drv,
 214                                         struct cpuidle_device *dev);
 215         void (*reflect)         (struct cpuidle_device *dev, int index);
 216
 217         struct module           *owner;
 218 };
 219
 220 #ifdef CONFIG_CPU_IDLE
 221 extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 222 #else
 223 static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 224 {return 0;}
 225 #endif
 226
 227 #ifdef CONFIG_ARCH_HAS_CPU_RELAX
 228 #define CPUIDLE_DRIVER_STATE_START      1
 229 #else
 230 #define CPUIDLE_DRIVER_STATE_START      0
 231 #endif
 232
 233 #endif /* _LINUX_CPUIDLE_H */