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