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 #ifdef CONFIG_SMP
  77 #ifdef CONFIG_ARCH_HAS_CPU_IDLE_WAIT
  78 static inline void cpuidle_kick_cpus(void)
  79 {
  80         cpu_idle_wait();
  81 }
  82 #else /* !CONFIG_ARCH_HAS_CPU_IDLE_WAIT */
  83 #error "Arch needs cpu_idle_wait() equivalent here"
  84 #endif /* !CONFIG_ARCH_HAS_CPU_IDLE_WAIT */
  85 #else /* !CONFIG_SMP */
  86 static inline void cpuidle_kick_cpus(void) {}
  87 #endif /* !CONFIG_SMP */
  88
  89 struct cpuidle_state_kobj {
  90         struct cpuidle_state *state;
  91         struct completion kobj_unregister;
  92         struct kobject kobj;
  93 };
  94
  95 struct cpuidle_device {
  96         unsigned int            enabled:1;
  97         unsigned int            cpu;
  98
  99         int                     last_residency;
 100         int                     state_count;
 101         struct cpuidle_state    states[CPUIDLE_STATE_MAX];
 102         struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
 103         struct cpuidle_state    *last_state;
 104
 105         struct list_head        device_list;
 106         struct kobject          kobj;
 107         struct completion       kobj_unregister;
 108         void                    *governor_data;
 109         struct cpuidle_state    *safe_state;
 110 };
 111
 112 DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
 113
 114 /**
 115  * cpuidle_get_last_residency - retrieves the last state's residency time
 116  * @dev: the target CPU
 117  *
 118  * NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
 119  */
 120 static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
 121 {
 122         return dev->last_residency;
 123 }
 124
 125
 126 /****************************
 127  * CPUIDLE DRIVER INTERFACE *
 128  ****************************/
 129
 130 struct cpuidle_driver {
 131         char                    name[CPUIDLE_NAME_LEN];
 132         struct module           *owner;
 133 };
 134
 135 #ifdef CONFIG_CPU_IDLE
 136
 137 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 138 extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 139 extern int cpuidle_register_device(struct cpuidle_device *dev);
 140 extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 141
 142 extern void cpuidle_pause_and_lock(void);
 143 extern void cpuidle_resume_and_unlock(void);
 144 extern int cpuidle_enable_device(struct cpuidle_device *dev);
 145 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 146
 147 #else
 148
 149 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 150 {return 0;}
 151 static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 152 static inline int cpuidle_register_device(struct cpuidle_device *dev)
 153 {return 0;}
 154 static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 155
 156 static inline void cpuidle_pause_and_lock(void) { }
 157 static inline void cpuidle_resume_and_unlock(void) { }
 158 static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 159 {return 0;}
 160 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 161
 162 #endif
 163
 164 /******************************
 165  * CPUIDLE GOVERNOR INTERFACE *
 166  ******************************/
 167
 168 struct cpuidle_governor {
 169         char                    name[CPUIDLE_NAME_LEN];
 170         struct list_head        governor_list;
 171         unsigned int            rating;
 172
 173         int  (*enable)          (struct cpuidle_device *dev);
 174         void (*disable)         (struct cpuidle_device *dev);
 175
 176         int  (*select)          (struct cpuidle_device *dev);
 177         void (*reflect)         (struct cpuidle_device *dev);
 178
 179         struct module           *owner;
 180 };
 181
 182 #ifdef CONFIG_CPU_IDLE
 183
 184 extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 185 extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
 186
 187 #else
 188
 189 static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 190 {return 0;}
 191 static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
 192
 193 #endif
 194
 195 #ifdef CONFIG_ARCH_HAS_CPU_RELAX
 196 #define CPUIDLE_DRIVER_STATE_START      1
 197 #else
 198 #define CPUIDLE_DRIVER_STATE_START      0
 199 #endif
 200
 201 #endif /* _LINUX_CPUIDLE_H */