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 long long      usage;
  42         unsigned long long      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 #define CPUIDLE_FLAG_IGNORE     (0x100) /* ignore during this idle period */
  56
  57 #define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
  58
  59 /**
  60  * cpuidle_get_statedata - retrieves private driver state data
  61  * @state: the state
  62  */
  63 static inline void * cpuidle_get_statedata(struct cpuidle_state *state)
  64 {
  65         return state->driver_data;
  66 }
  67
  68 /**
  69  * cpuidle_set_statedata - stores private driver state data
  70  * @state: the state
  71  * @data: the private data
  72  */
  73 static inline void
  74 cpuidle_set_statedata(struct cpuidle_state *state, void *data)
  75 {
  76         state->driver_data = data;
  77 }
  78
  79 struct cpuidle_state_kobj {
  80         struct cpuidle_state *state;
  81         struct completion kobj_unregister;
  82         struct kobject kobj;
  83 };
  84
  85 struct cpuidle_device {
  86         unsigned int            registered:1;
  87         unsigned int            enabled:1;
  88         unsigned int            power_specified:1;
  89         unsigned int            cpu;
  90
  91         int                     last_residency;
  92         int                     state_count;
  93         struct cpuidle_state    states[CPUIDLE_STATE_MAX];
  94         struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
  95         struct cpuidle_state    *last_state;
  96
  97         struct list_head        device_list;
  98         struct kobject          kobj;
  99         struct completion       kobj_unregister;
 100         void                    *governor_data;
 101         struct cpuidle_state    *safe_state;
 102
 103         int (*prepare)          (struct cpuidle_device *dev);
 104 };
 105
 106 DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
 107
 108 /**
 109  * cpuidle_get_last_residency - retrieves the last state's residency time
 110  * @dev: the target CPU
 111  *
 112  * NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
 113  */
 114 static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
 115 {
 116         return dev->last_residency;
 117 }
 118
 119
 120 /****************************
 121  * CPUIDLE DRIVER INTERFACE *
 122  ****************************/
 123
 124 struct cpuidle_driver {
 125         char                    name[CPUIDLE_NAME_LEN];
 126         struct module           *owner;
 127 };
 128
 129 #ifdef CONFIG_CPU_IDLE
 130
 131 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 132 struct cpuidle_driver *cpuidle_get_driver(void);
 133 extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 134 extern int cpuidle_register_device(struct cpuidle_device *dev);
 135 extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 136
 137 extern void cpuidle_pause_and_lock(void);
 138 extern void cpuidle_resume_and_unlock(void);
 139 extern int cpuidle_enable_device(struct cpuidle_device *dev);
 140 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 141
 142 #else
 143
 144 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 145 {return -ENODEV; }
 146 static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
 147 static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 148 static inline int cpuidle_register_device(struct cpuidle_device *dev)
 149 {return -ENODEV; }
 150 static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 151
 152 static inline void cpuidle_pause_and_lock(void) { }
 153 static inline void cpuidle_resume_and_unlock(void) { }
 154 static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 155 {return -ENODEV; }
 156 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 157
 158 #endif
 159
 160 /******************************
 161  * CPUIDLE GOVERNOR INTERFACE *
 162  ******************************/
 163
 164 struct cpuidle_governor {
 165         char                    name[CPUIDLE_NAME_LEN];
 166         struct list_head        governor_list;
 167         unsigned int            rating;
 168
 169         int  (*enable)          (struct cpuidle_device *dev);
 170         void (*disable)         (struct cpuidle_device *dev);
 171
 172         int  (*select)          (struct cpuidle_device *dev);
 173         void (*reflect)         (struct cpuidle_device *dev);
 174
 175         struct module           *owner;
 176 };
 177
 178 #ifdef CONFIG_CPU_IDLE
 179
 180 extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 181 extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
 182
 183 #else
 184
 185 static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 186 {return 0;}
 187 static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
 188
 189 #endif
 190
 191 #ifdef CONFIG_ARCH_HAS_CPU_RELAX
 192 #define CPUIDLE_DRIVER_STATE_START      1
 193 #else
 194 #define CPUIDLE_DRIVER_STATE_START      0
 195 #endif
 196
 197 #endif /* _LINUX_CPUIDLE_H */