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         struct cpuidle_state    *safe_state;
  96 };
  97
  98 DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
  99
 100 /**
 101  * cpuidle_get_last_residency - retrieves the last state's residency time
 102  * @dev: the target CPU
 103  *
 104  * NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
 105  */
 106 static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
 107 {
 108         return dev->last_residency;
 109 }
 110
 111
 112 /****************************
 113  * CPUIDLE DRIVER INTERFACE *
 114  ****************************/
 115
 116 struct cpuidle_driver {
 117         char                    name[CPUIDLE_NAME_LEN];
 118         struct module           *owner;
 119 };
 120
 121 #ifdef CONFIG_CPU_IDLE
 122
 123 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 124 extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 125 extern int cpuidle_register_device(struct cpuidle_device *dev);
 126 extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 127
 128 extern void cpuidle_pause_and_lock(void);
 129 extern void cpuidle_resume_and_unlock(void);
 130 extern int cpuidle_enable_device(struct cpuidle_device *dev);
 131 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 132
 133 #else
 134
 135 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 136 {return 0;}
 137 static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 138 static inline int cpuidle_register_device(struct cpuidle_device *dev)
 139 {return 0;}
 140 static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 141
 142 static inline void cpuidle_pause_and_lock(void) { }
 143 static inline void cpuidle_resume_and_unlock(void) { }
 144 static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 145 {return 0;}
 146 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 147
 148 #endif
 149
 150 /******************************
 151  * CPUIDLE GOVERNOR INTERFACE *
 152  ******************************/
 153
 154 struct cpuidle_governor {
 155         char                    name[CPUIDLE_NAME_LEN];
 156         struct list_head        governor_list;
 157         unsigned int            rating;
 158
 159         int  (*enable)          (struct cpuidle_device *dev);
 160         void (*disable)         (struct cpuidle_device *dev);
 161
 162         int  (*select)          (struct cpuidle_device *dev);
 163         void (*reflect)         (struct cpuidle_device *dev);
 164
 165         struct module           *owner;
 166 };
 167
 168 #ifdef CONFIG_CPU_IDLE
 169
 170 extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 171 extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
 172
 173 #else
 174
 175 static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 176 {return 0;}
 177 static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
 178
 179 #endif
 180
 181 #endif /* _LINUX_CPUIDLE_H */