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_POLL       (0x10) /* no latency, no savings */
  50 #define CPUIDLE_FLAG_SHALLOW    (0x20) /* low latency, minimal savings */
  51 #define CPUIDLE_FLAG_BALANCED   (0x40) /* medium latency, moderate savings */
  52 #define CPUIDLE_FLAG_DEEP       (0x80) /* high latency, large savings */
  53
  54 #define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
  55
  56 /**
  57  * cpuidle_get_statedata - retrieves private driver state data
  58  * @state: the state
  59  */
  60 static inline void * cpuidle_get_statedata(struct cpuidle_state *state)
  61 {
  62         return state->driver_data;
  63 }
  64
  65 /**
  66  * cpuidle_set_statedata - stores private driver state data
  67  * @state: the state
  68  * @data: the private data
  69  */
  70 static inline void
  71 cpuidle_set_statedata(struct cpuidle_state *state, void *data)
  72 {
  73         state->driver_data = data;
  74 }
  75
  76 struct cpuidle_state_kobj {
  77         struct cpuidle_state *state;
  78         struct completion kobj_unregister;
  79         struct kobject kobj;
  80 };
  81
  82 struct cpuidle_device {
  83         unsigned int            enabled:1;
  84         unsigned int            cpu;
  85
  86         int                     last_residency;
  87         int                     state_count;
  88         struct cpuidle_state    states[CPUIDLE_STATE_MAX];
  89         struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
  90         struct cpuidle_state    *last_state;
  91
  92         struct list_head        device_list;
  93         struct kobject          kobj;
  94         struct completion       kobj_unregister;
  95         void                    *governor_data;
  96         struct cpuidle_state    *safe_state;
  97 };
  98
  99 DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
 100
 101 /**
 102  * cpuidle_get_last_residency - retrieves the last state's residency time
 103  * @dev: the target CPU
 104  *
 105  * NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
 106  */
 107 static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
 108 {
 109         return dev->last_residency;
 110 }
 111
 112
 113 /****************************
 114  * CPUIDLE DRIVER INTERFACE *
 115  ****************************/
 116
 117 struct cpuidle_driver {
 118         char                    name[CPUIDLE_NAME_LEN];
 119         struct module           *owner;
 120 };
 121
 122 #ifdef CONFIG_CPU_IDLE
 123
 124 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 125 extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 126 extern int cpuidle_register_device(struct cpuidle_device *dev);
 127 extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 128
 129 extern void cpuidle_pause_and_lock(void);
 130 extern void cpuidle_resume_and_unlock(void);
 131 extern int cpuidle_enable_device(struct cpuidle_device *dev);
 132 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 133
 134 #else
 135
 136 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 137 {return 0;}
 138 static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 139 static inline int cpuidle_register_device(struct cpuidle_device *dev)
 140 {return 0;}
 141 static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 142
 143 static inline void cpuidle_pause_and_lock(void) { }
 144 static inline void cpuidle_resume_and_unlock(void) { }
 145 static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 146 {return 0;}
 147 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 148
 149 #endif
 150
 151 /******************************
 152  * CPUIDLE GOVERNOR INTERFACE *
 153  ******************************/
 154
 155 struct cpuidle_governor {
 156         char                    name[CPUIDLE_NAME_LEN];
 157         struct list_head        governor_list;
 158         unsigned int            rating;
 159
 160         int  (*enable)          (struct cpuidle_device *dev);
 161         void (*disable)         (struct cpuidle_device *dev);
 162
 163         int  (*select)          (struct cpuidle_device *dev);
 164         void (*reflect)         (struct cpuidle_device *dev);
 165
 166         struct module           *owner;
 167 };
 168
 169 #ifdef CONFIG_CPU_IDLE
 170
 171 extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 172 extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
 173
 174 #else
 175
 176 static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 177 {return 0;}
 178 static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
 179
 180 #endif
 181
 182 #ifdef CONFIG_ARCH_HAS_CPU_RELAX
 183 #define CPUIDLE_DRIVER_STATE_START      1
 184 #else
 185 #define CPUIDLE_DRIVER_STATE_START      0
 186 #endif
 187
 188 #endif /* _LINUX_CPUIDLE_H */