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/kobject.h>
  17 #include <linux/completion.h>
  18
  19 #define CPUIDLE_STATE_MAX       8
  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 struct cpuidle_state_usage {
  34         void            *driver_data;
  35
  36         unsigned long long      usage;
  37         unsigned long long      time; /* in US */
  38 };
  39
  40 struct cpuidle_state {
  41         char            name[CPUIDLE_NAME_LEN];
  42         char            desc[CPUIDLE_DESC_LEN];
  43
  44         unsigned int    flags;
  45         unsigned int    exit_latency; /* in US */
  46         unsigned int    power_usage; /* in mW */
  47         unsigned int    target_residency; /* in US */
  48
  49         int (*enter)    (struct cpuidle_device *dev,
  50                         struct cpuidle_driver *drv,
  51                         int index);
  52 };
  53
  54 /* Idle State Flags */
  55 #define CPUIDLE_FLAG_TIME_VALID (0x01) /* is residency time measurable? */
  56
  57 #define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
  58
  59 /**
  60  * cpuidle_get_statedata - retrieves private driver state data
  61  * @st_usage: the state usage statistics
  62  */
  63 static inline void *cpuidle_get_statedata(struct cpuidle_state_usage *st_usage)
  64 {
  65         return st_usage->driver_data;
  66 }
  67
  68 /**
  69  * cpuidle_set_statedata - stores private driver state data
  70  * @st_usage: the state usage statistics
  71  * @data: the private data
  72  */
  73 static inline void
  74 cpuidle_set_statedata(struct cpuidle_state_usage *st_usage, void *data)
  75 {
  76         st_usage->driver_data = data;
  77 }
  78
  79 struct cpuidle_state_kobj {
  80         struct cpuidle_state *state;
  81         struct cpuidle_state_usage *state_usage;
  82         struct completion kobj_unregister;
  83         struct kobject kobj;
  84 };
  85
  86 struct cpuidle_device {
  87         unsigned int            registered:1;
  88         unsigned int            enabled:1;
  89         unsigned int            cpu;
  90
  91         int                     last_residency;
  92         int                     state_count;
  93         struct cpuidle_state_usage      states_usage[CPUIDLE_STATE_MAX];
  94         struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
  95
  96         struct list_head        device_list;
  97         struct kobject          kobj;
  98         struct completion       kobj_unregister;
  99         void                    *governor_data;
 100 };
 101
 102 DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
 103
 104 /**
 105  * cpuidle_get_last_residency - retrieves the last state's residency time
 106  * @dev: the target CPU
 107  *
 108  * NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
 109  */
 110 static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
 111 {
 112         return dev->last_residency;
 113 }
 114
 115
 116 /****************************
 117  * CPUIDLE DRIVER INTERFACE *
 118  ****************************/
 119
 120 struct cpuidle_driver {
 121         char                    name[CPUIDLE_NAME_LEN];
 122         struct module           *owner;
 123
 124         unsigned int            power_specified:1;
 125         struct cpuidle_state    states[CPUIDLE_STATE_MAX];
 126         int                     state_count;
 127         int                     safe_state_index;
 128 };
 129
 130 #ifdef CONFIG_CPU_IDLE
 131 extern void disable_cpuidle(void);
 132 extern int cpuidle_idle_call(void);
 133 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 134 struct cpuidle_driver *cpuidle_get_driver(void);
 135 extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 136 extern int cpuidle_register_device(struct cpuidle_device *dev);
 137 extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 138
 139 extern void cpuidle_pause_and_lock(void);
 140 extern void cpuidle_resume_and_unlock(void);
 141 extern int cpuidle_enable_device(struct cpuidle_device *dev);
 142 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 143
 144 #else
 145 static inline void disable_cpuidle(void) { }
 146 static inline int cpuidle_idle_call(void) { return -ENODEV; }
 147 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 148 {return -ENODEV; }
 149 static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
 150 static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 151 static inline int cpuidle_register_device(struct cpuidle_device *dev)
 152 {return -ENODEV; }
 153 static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 154
 155 static inline void cpuidle_pause_and_lock(void) { }
 156 static inline void cpuidle_resume_and_unlock(void) { }
 157 static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 158 {return -ENODEV; }
 159 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 160
 161 #endif
 162
 163 /******************************
 164  * CPUIDLE GOVERNOR INTERFACE *
 165  ******************************/
 166
 167 struct cpuidle_governor {
 168         char                    name[CPUIDLE_NAME_LEN];
 169         struct list_head        governor_list;
 170         unsigned int            rating;
 171
 172         int  (*enable)          (struct cpuidle_driver *drv,
 173                                         struct cpuidle_device *dev);
 174         void (*disable)         (struct cpuidle_driver *drv,
 175                                         struct cpuidle_device *dev);
 176
 177         int  (*select)          (struct cpuidle_driver *drv,
 178                                         struct cpuidle_device *dev);
 179         void (*reflect)         (struct cpuidle_device *dev, int index);
 180
 181         struct module           *owner;
 182 };
 183
 184 #ifdef CONFIG_CPU_IDLE
 185
 186 extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 187 extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
 188
 189 #else
 190
 191 static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 192 {return 0;}
 193 static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
 194
 195 #endif
 196
 197 #ifdef CONFIG_ARCH_HAS_CPU_RELAX
 198 #define CPUIDLE_DRIVER_STATE_START      1
 199 #else
 200 #define CPUIDLE_DRIVER_STATE_START      0
 201 #endif
 202
 203 #endif /* _LINUX_CPUIDLE_H */