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/module.h>
  17 #include <linux/kobject.h>
  18 #include <linux/completion.h>
  19
  20 #define CPUIDLE_STATE_MAX       8
  21 #define CPUIDLE_NAME_LEN        16
  22 #define CPUIDLE_DESC_LEN        32
  23
  24 struct cpuidle_device;
  25
  26
  27 /****************************
  28  * CPUIDLE DEVICE INTERFACE *
  29  ****************************/
  30
  31 struct cpuidle_state {
  32         char            name[CPUIDLE_NAME_LEN];
  33         char            desc[CPUIDLE_DESC_LEN];
  34         void            *driver_data;
  35
  36         unsigned int    flags;
  37         unsigned int    exit_latency; /* in US */
  38         unsigned int    power_usage; /* in mW */
  39         unsigned int    target_residency; /* in US */
  40
  41         unsigned int    usage;
  42         unsigned int    time; /* in US */
  43
  44         int (*enter)    (struct cpuidle_device *dev,
  45                          struct cpuidle_state *state);
  46 };
  47
  48 /* Idle State Flags */
  49 #define CPUIDLE_FLAG_TIME_VALID (0x01) /* is residency time measurable? */
  50 #define CPUIDLE_FLAG_CHECK_BM   (0x02) /* BM activity will exit state */
  51 #define CPUIDLE_FLAG_POLL       (0x10) /* no latency, no savings */
  52 #define CPUIDLE_FLAG_SHALLOW    (0x20) /* low latency, minimal savings */
  53 #define CPUIDLE_FLAG_BALANCED   (0x40) /* medium latency, moderate savings */
  54 #define CPUIDLE_FLAG_DEEP       (0x80) /* high latency, large savings */
  55
  56 #define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
  57
  58 /**
  59  * cpuidle_get_statedata - retrieves private driver state data
  60  * @state: the state
  61  */
  62 static inline void * cpuidle_get_statedata(struct cpuidle_state *state)
  63 {
  64         return state->driver_data;
  65 }
  66
  67 /**
  68  * cpuidle_set_statedata - stores private driver state data
  69  * @state: the state
  70  * @data: the private data
  71  */
  72 static inline void
  73 cpuidle_set_statedata(struct cpuidle_state *state, void *data)
  74 {
  75         state->driver_data = data;
  76 }
  77
  78 struct cpuidle_state_kobj {
  79         struct cpuidle_state *state;
  80         struct completion kobj_unregister;
  81         struct kobject kobj;
  82 };
  83
  84 struct cpuidle_device {
  85         unsigned int            enabled:1;
  86         unsigned int            cpu;
  87
  88         int                     last_residency;
  89         int                     state_count;
  90         struct cpuidle_state    states[CPUIDLE_STATE_MAX];
  91         struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
  92         struct cpuidle_state    *last_state;
  93
  94         struct list_head        device_list;
  95         struct kobject          kobj;
  96         struct completion       kobj_unregister;
  97         void                    *governor_data;
  98         struct cpuidle_state    *safe_state;
  99 };
 100
 101 DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
 102
 103 /**
 104  * cpuidle_get_last_residency - retrieves the last state's residency time
 105  * @dev: the target CPU
 106  *
 107  * NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
 108  */
 109 static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
 110 {
 111         return dev->last_residency;
 112 }
 113
 114
 115 /****************************
 116  * CPUIDLE DRIVER INTERFACE *
 117  ****************************/
 118
 119 struct cpuidle_driver {
 120         char                    name[CPUIDLE_NAME_LEN];
 121         struct module           *owner;
 122 };
 123
 124 #ifdef CONFIG_CPU_IDLE
 125
 126 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 127 extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 128 extern int cpuidle_register_device(struct cpuidle_device *dev);
 129 extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 130
 131 extern void cpuidle_pause_and_lock(void);
 132 extern void cpuidle_resume_and_unlock(void);
 133 extern int cpuidle_enable_device(struct cpuidle_device *dev);
 134 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 135
 136 #else
 137
 138 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 139 {return 0;}
 140 static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 141 static inline int cpuidle_register_device(struct cpuidle_device *dev)
 142 {return 0;}
 143 static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 144
 145 static inline void cpuidle_pause_and_lock(void) { }
 146 static inline void cpuidle_resume_and_unlock(void) { }
 147 static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 148 {return 0;}
 149 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 150
 151 #endif
 152
 153 /******************************
 154  * CPUIDLE GOVERNOR INTERFACE *
 155  ******************************/
 156
 157 struct cpuidle_governor {
 158         char                    name[CPUIDLE_NAME_LEN];
 159         struct list_head        governor_list;
 160         unsigned int            rating;
 161
 162         int  (*enable)          (struct cpuidle_device *dev);
 163         void (*disable)         (struct cpuidle_device *dev);
 164
 165         int  (*select)          (struct cpuidle_device *dev);
 166         void (*reflect)         (struct cpuidle_device *dev);
 167
 168         struct module           *owner;
 169 };
 170
 171 #ifdef CONFIG_CPU_IDLE
 172
 173 extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 174 extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
 175
 176 #else
 177
 178 static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 179 {return 0;}
 180 static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
 181
 182 #endif
 183
 184 #ifdef CONFIG_ARCH_HAS_CPU_RELAX
 185 #define CPUIDLE_DRIVER_STATE_START      1
 186 #else
 187 #define CPUIDLE_DRIVER_STATE_START      0
 188 #endif
 189
 190 #endif /* _LINUX_CPUIDLE_H */