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_IGNORE     (0x100) /* ignore during this idle period */
  51
  52 #define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
  53
  54 /**
  55  * cpuidle_get_statedata - retrieves private driver state data
  56  * @state: the state
  57  */
  58 static inline void * cpuidle_get_statedata(struct cpuidle_state *state)
  59 {
  60         return state->driver_data;
  61 }
  62
  63 /**
  64  * cpuidle_set_statedata - stores private driver state data
  65  * @state: the state
  66  * @data: the private data
  67  */
  68 static inline void
  69 cpuidle_set_statedata(struct cpuidle_state *state, void *data)
  70 {
  71         state->driver_data = data;
  72 }
  73
  74 struct cpuidle_state_kobj {
  75         struct cpuidle_state *state;
  76         struct completion kobj_unregister;
  77         struct kobject kobj;
  78 };
  79
  80 struct cpuidle_device {
  81         unsigned int            registered:1;
  82         unsigned int            enabled:1;
  83         unsigned int            power_specified: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         int (*prepare)          (struct cpuidle_device *dev);
  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 struct cpuidle_driver *cpuidle_get_driver(void);
 128 extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 129 extern int cpuidle_register_device(struct cpuidle_device *dev);
 130 extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 131
 132 extern void cpuidle_pause_and_lock(void);
 133 extern void cpuidle_resume_and_unlock(void);
 134 extern int cpuidle_enable_device(struct cpuidle_device *dev);
 135 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 136
 137 #else
 138
 139 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 140 {return -ENODEV; }
 141 static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
 142 static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 143 static inline int cpuidle_register_device(struct cpuidle_device *dev)
 144 {return -ENODEV; }
 145 static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 146
 147 static inline void cpuidle_pause_and_lock(void) { }
 148 static inline void cpuidle_resume_and_unlock(void) { }
 149 static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 150 {return -ENODEV; }
 151 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 152
 153 #endif
 154
 155 /******************************
 156  * CPUIDLE GOVERNOR INTERFACE *
 157  ******************************/
 158
 159 struct cpuidle_governor {
 160         char                    name[CPUIDLE_NAME_LEN];
 161         struct list_head        governor_list;
 162         unsigned int            rating;
 163
 164         int  (*enable)          (struct cpuidle_device *dev);
 165         void (*disable)         (struct cpuidle_device *dev);
 166
 167         int  (*select)          (struct cpuidle_device *dev);
 168         void (*reflect)         (struct cpuidle_device *dev);
 169
 170         struct module           *owner;
 171 };
 172
 173 #ifdef CONFIG_CPU_IDLE
 174
 175 extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 176 extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
 177
 178 #else
 179
 180 static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 181 {return 0;}
 182 static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
 183
 184 #endif
 185
 186 #ifdef CONFIG_ARCH_HAS_CPU_RELAX
 187 #define CPUIDLE_DRIVER_STATE_START      1
 188 #else
 189 #define CPUIDLE_DRIVER_STATE_START      0
 190 #endif
 191
 192 #endif /* _LINUX_CPUIDLE_H */