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
  23 struct cpuidle_device;
  24
  25
  26 /****************************
  27  * CPUIDLE DEVICE INTERFACE *
  28  ****************************/
  29
  30 struct cpuidle_state {
  31         char            name[CPUIDLE_NAME_LEN];
  32         void            *driver_data;
  33
  34         unsigned int    flags;
  35         unsigned int    exit_latency; /* in US */
  36         unsigned int    power_usage; /* in mW */
  37         unsigned int    target_residency; /* in US */
  38
  39         unsigned int    usage;
  40         unsigned int    time; /* in US */
  41
  42         int (*enter)    (struct cpuidle_device *dev,
  43                          struct cpuidle_state *state);
  44 };
  45
  46 /* Idle State Flags */
  47 #define CPUIDLE_FLAG_TIME_VALID (0x01) /* is residency time measurable? */
  48 #define CPUIDLE_FLAG_CHECK_BM   (0x02) /* BM activity will exit state */
  49 #define CPUIDLE_FLAG_SHALLOW    (0x10) /* low latency, minimal savings */
  50 #define CPUIDLE_FLAG_BALANCED   (0x20) /* medium latency, moderate savings */
  51 #define CPUIDLE_FLAG_DEEP       (0x40) /* high latency, large savings */
  52
  53 #define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
  54
  55 /**
  56  * cpuidle_get_statedata - retrieves private driver state data
  57  * @state: the state
  58  */
  59 static inline void * cpuidle_get_statedata(struct cpuidle_state *state)
  60 {
  61         return state->driver_data;
  62 }
  63
  64 /**
  65  * cpuidle_set_statedata - stores private driver state data
  66  * @state: the state
  67  * @data: the private data
  68  */
  69 static inline void
  70 cpuidle_set_statedata(struct cpuidle_state *state, void *data)
  71 {
  72         state->driver_data = data;
  73 }
  74
  75 struct cpuidle_state_kobj {
  76         struct cpuidle_state *state;
  77         struct completion kobj_unregister;
  78         struct kobject kobj;
  79 };
  80
  81 struct cpuidle_device {
  82         int                     enabled:1;
  83         unsigned int            cpu;
  84
  85         int                     last_residency;
  86         int                     state_count;
  87         struct cpuidle_state    states[CPUIDLE_STATE_MAX];
  88         struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
  89         struct cpuidle_state    *last_state;
  90
  91         struct list_head        device_list;
  92         struct kobject          kobj;
  93         struct completion       kobj_unregister;
  94         void                    *governor_data;
  95 };
  96
  97 DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
  98
  99 /**
 100  * cpuidle_get_last_residency - retrieves the last state's residency time
 101  * @dev: the target CPU
 102  *
 103  * NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
 104  */
 105 static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
 106 {
 107         return dev->last_residency;
 108 }
 109
 110
 111 /****************************
 112  * CPUIDLE DRIVER INTERFACE *
 113  ****************************/
 114
 115 struct cpuidle_driver {
 116         char                    name[CPUIDLE_NAME_LEN];
 117         struct module           *owner;
 118 };
 119
 120 #ifdef CONFIG_CPU_IDLE
 121
 122 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 123 extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 124 extern int cpuidle_register_device(struct cpuidle_device *dev);
 125 extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 126
 127 extern void cpuidle_pause_and_lock(void);
 128 extern void cpuidle_resume_and_unlock(void);
 129 extern int cpuidle_enable_device(struct cpuidle_device *dev);
 130 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 131
 132 #else
 133
 134 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 135 {return 0;}
 136 static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 137 static inline int cpuidle_register_device(struct cpuidle_device *dev)
 138 {return 0;}
 139 static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 140
 141 static inline void cpuidle_pause_and_lock(void) { }
 142 static inline void cpuidle_resume_and_unlock(void) { }
 143 static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 144 {return 0;}
 145 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 146
 147 #endif
 148
 149 /******************************
 150  * CPUIDLE GOVERNOR INTERFACE *
 151  ******************************/
 152
 153 struct cpuidle_governor {
 154         char                    name[CPUIDLE_NAME_LEN];
 155         struct list_head        governor_list;
 156         unsigned int            rating;
 157
 158         int  (*enable)          (struct cpuidle_device *dev);
 159         void (*disable)         (struct cpuidle_device *dev);
 160
 161         int  (*select)          (struct cpuidle_device *dev);
 162         void (*reflect)         (struct cpuidle_device *dev);
 163
 164         struct module           *owner;
 165 };
 166
 167 #ifdef CONFIG_CPU_IDLE
 168
 169 extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 170 extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
 171
 172 #else
 173
 174 static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 175 {return 0;}
 176 static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
 177
 178 #endif
 179
 180 #endif /* _LINUX_CPUIDLE_H */