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_IGNORE     (0x100) /* ignore during this idle period */
  52 #define CPUIDLE_FLAG_TLB_FLUSHED (0x200) /* tlb will be flushed */
  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 struct cpuidle_state_kobj {
  77         struct cpuidle_state *state;
  78         struct completion kobj_unregister;
  79         struct kobject kobj;
  80 };
  81
  82 struct cpuidle_device {
  83         unsigned int            registered:1;
  84         unsigned int            enabled:1;
  85         unsigned int            power_specified:1;
  86         unsigned int            cpu;
  87
  88         int                     last_residency;
  89         int                     state_count;
  90         struct cpuidle_state    states[CPUIDLE_STATE_MAX];
  91         struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
  92         struct cpuidle_state    *last_state;
  93
  94         struct list_head        device_list;
  95         struct kobject          kobj;
  96         struct completion       kobj_unregister;
  97         void                    *governor_data;
  98         struct cpuidle_state    *safe_state;
  99
 100         int (*prepare)          (struct cpuidle_device *dev);
 101 };
 102
 103 DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
 104
 105 /**
 106  * cpuidle_get_last_residency - retrieves the last state's residency time
 107  * @dev: the target CPU
 108  *
 109  * NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
 110  */
 111 static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
 112 {
 113         return dev->last_residency;
 114 }
 115
 116
 117 /****************************
 118  * CPUIDLE DRIVER INTERFACE *
 119  ****************************/
 120
 121 struct cpuidle_driver {
 122         char                    name[CPUIDLE_NAME_LEN];
 123         struct module           *owner;
 124 };
 125
 126 #ifdef CONFIG_CPU_IDLE
 127
 128 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 129 struct cpuidle_driver *cpuidle_get_driver(void);
 130 extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
 131 extern int cpuidle_register_device(struct cpuidle_device *dev);
 132 extern void cpuidle_unregister_device(struct cpuidle_device *dev);
 133
 134 extern void cpuidle_pause_and_lock(void);
 135 extern void cpuidle_resume_and_unlock(void);
 136 extern int cpuidle_enable_device(struct cpuidle_device *dev);
 137 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 138
 139 #else
 140
 141 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 142 {return -ENODEV; }
 143 static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
 144 static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
 145 static inline int cpuidle_register_device(struct cpuidle_device *dev)
 146 {return -ENODEV; }
 147 static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
 148
 149 static inline void cpuidle_pause_and_lock(void) { }
 150 static inline void cpuidle_resume_and_unlock(void) { }
 151 static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 152 {return -ENODEV; }
 153 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 154
 155 #endif
 156
 157 /******************************
 158  * CPUIDLE GOVERNOR INTERFACE *
 159  ******************************/
 160
 161 struct cpuidle_governor {
 162         char                    name[CPUIDLE_NAME_LEN];
 163         struct list_head        governor_list;
 164         unsigned int            rating;
 165
 166         int  (*enable)          (struct cpuidle_device *dev);
 167         void (*disable)         (struct cpuidle_device *dev);
 168
 169         int  (*select)          (struct cpuidle_device *dev);
 170         void (*reflect)         (struct cpuidle_device *dev);
 171
 172         struct module           *owner;
 173 };
 174
 175 #ifdef CONFIG_CPU_IDLE
 176
 177 extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 178 extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
 179
 180 #else
 181
 182 static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 183 {return 0;}
 184 static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
 185
 186 #endif
 187
 188 #ifdef CONFIG_ARCH_HAS_CPU_RELAX
 189 #define CPUIDLE_DRIVER_STATE_START      1
 190 #else
 191 #define CPUIDLE_DRIVER_STATE_START      0
 192 #endif
 193
 194 #endif /* _LINUX_CPUIDLE_H */