release/src-rt-6.x.4708/linux/linux-2.6.36/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 #define CPUIDLE_FLAG_TLB_FLUSHED (0x200) /* tlb will be flushed */
  57
  58 #define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
  59
  60 /**
  61  * cpuidle_get_statedata - retrieves private driver state data
  62  * @state: the state
  63  */
  64 static inline void * cpuidle_get_statedata(struct cpuidle_state *state)
  65 {
  66         return state->driver_data;
  67 }
  68
  69 /**
  70  * cpuidle_set_statedata - stores private driver state data
  71  * @state: the state
  72  * @data: the private data
  73  */
  74 static inline void
  75 cpuidle_set_statedata(struct cpuidle_state *state, void *data)
  76 {
  77         state->driver_data = data;
  78 }
  79
  80 struct cpuidle_state_kobj {
  81         struct cpuidle_state *state;
  82         struct completion kobj_unregister;
  83         struct kobject kobj;
  84 };
  85
  86 struct cpuidle_device {
  87         unsigned int            registered:1;
  88         unsigned int            enabled:1;
  89         unsigned int            power_specified:1;
  90         unsigned int            cpu;
  91
  92         int                     last_residency;
  93         int                     state_count;
  94         struct cpuidle_state    states[CPUIDLE_STATE_MAX];
  95         struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
  96         struct cpuidle_state    *last_state;
  97
  98         struct list_head        device_list;
  99         struct kobject          kobj;
 100         struct completion       kobj_unregister;
 101         void                    *governor_data;
 102         struct cpuidle_state    *safe_state;
 103
 104         int (*prepare)          (struct cpuidle_device *dev);
 105 };
 106
 107 DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
 108
 109 /**
 110  * cpuidle_get_last_residency - retrieves the last state's residency time
 111  * @dev: the target CPU
 112  *
 113  * NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
 114  */
 115 static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
 116 {
 117         return dev->last_residency;
 118 }
 119
 120
 121 /****************************
 122  * CPUIDLE DRIVER INTERFACE *
 123  ****************************/
 124
 125 struct cpuidle_driver {
 126         char                    name[CPUIDLE_NAME_LEN];
 127         struct module           *owner;
 128 };
 129
 130 #ifdef CONFIG_CPU_IDLE
 131
 132 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 133 struct cpuidle_driver *cpuidle_get_driver(void);
 134 extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 135 extern int cpuidle_register_device(struct cpuidle_device *dev);
 136 extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 137
 138 extern void cpuidle_pause_and_lock(void);
 139 extern void cpuidle_resume_and_unlock(void);
 140 extern int cpuidle_enable_device(struct cpuidle_device *dev);
 141 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 142
 143 #else
 144
 145 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 146 {return -ENODEV; }
 147 static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
 148 static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 149 static inline int cpuidle_register_device(struct cpuidle_device *dev)
 150 {return -ENODEV; }
 151 static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 152
 153 static inline void cpuidle_pause_and_lock(void) { }
 154 static inline void cpuidle_resume_and_unlock(void) { }
 155 static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 156 {return -ENODEV; }
 157 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 158
 159 #endif
 160
 161 /******************************
 162  * CPUIDLE GOVERNOR INTERFACE *
 163  ******************************/
 164
 165 struct cpuidle_governor {
 166         char                    name[CPUIDLE_NAME_LEN];
 167         struct list_head        governor_list;
 168         unsigned int            rating;
 169
 170         int  (*enable)          (struct cpuidle_device *dev);
 171         void (*disable)         (struct cpuidle_device *dev);
 172
 173         int  (*select)          (struct cpuidle_device *dev);
 174         void (*reflect)         (struct cpuidle_device *dev);
 175
 176         struct module           *owner;
 177 };
 178
 179 #ifdef CONFIG_CPU_IDLE
 180
 181 extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 182 extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
 183
 184 #else
 185
 186 static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 187 {return 0;}
 188 static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
 189
 190 #endif
 191
 192 #ifdef CONFIG_ARCH_HAS_CPU_RELAX
 193 #define CPUIDLE_DRIVER_STATE_START      1
 194 #else
 195 #define CPUIDLE_DRIVER_STATE_START      0
 196 #endif
 197
 198 #endif /* _LINUX_CPUIDLE_H */