2 * cpuidle.h - a generic framework for CPU idle power management
4 * (C) 2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
5 * Shaohua Li <shaohua.li@intel.com>
6 * Adam Belay <abelay@novell.com>
8 * This code is licenced under the GPL.
11 #ifndef _LINUX_CPUIDLE_H
12 #define _LINUX_CPUIDLE_H
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>
20 #define CPUIDLE_STATE_MAX 8
21 #define CPUIDLE_NAME_LEN 16
23 struct cpuidle_device;
26 /****************************
27 * CPUIDLE DEVICE INTERFACE *
28 ****************************/
30 struct cpuidle_state {
31 char name[CPUIDLE_NAME_LEN];
35 unsigned int exit_latency; /* in US */
36 unsigned int power_usage; /* in mW */
37 unsigned int target_residency; /* in US */
40 unsigned int time; /* in US */
42 int (*enter) (struct cpuidle_device *dev,
43 struct cpuidle_state *state);
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_SHALLOW (0x10) /* low latency, minimal savings */
50 #define CPUIDLE_FLAG_BALANCED (0x20) /* medium latency, moderate savings */
51 #define CPUIDLE_FLAG_DEEP (0x40) /* high latency, large savings */
53 #define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
56 * cpuidle_get_statedata - retrieves private driver state data
59 static inline void * cpuidle_get_statedata(struct cpuidle_state *state)
61 return state->driver_data;
65 * cpuidle_set_statedata - stores private driver state data
67 * @data: the private data
70 cpuidle_set_statedata(struct cpuidle_state *state, void *data)
72 state->driver_data = data;
76 #ifdef CONFIG_ARCH_HAS_CPU_IDLE_WAIT
77 static inline void cpuidle_kick_cpus(void)
81 #else /* !CONFIG_ARCH_HAS_CPU_IDLE_WAIT */
82 #error "Arch needs cpu_idle_wait() equivalent here"
83 #endif /* !CONFIG_ARCH_HAS_CPU_IDLE_WAIT */
84 #else /* !CONFIG_SMP */
85 static inline void cpuidle_kick_cpus(void) {}
86 #endif /* !CONFIG_SMP */
88 struct cpuidle_state_kobj {
89 struct cpuidle_state *state;
90 struct completion kobj_unregister;
94 struct cpuidle_device {
100 struct cpuidle_state states[CPUIDLE_STATE_MAX];
101 struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
102 struct cpuidle_state *last_state;
104 struct list_head device_list;
106 struct completion kobj_unregister;
110 DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
113 * cpuidle_get_last_residency - retrieves the last state's residency time
114 * @dev: the target CPU
116 * NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
118 static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
120 return dev->last_residency;
124 /****************************
125 * CPUIDLE DRIVER INTERFACE *
126 ****************************/
128 struct cpuidle_driver {
129 char name[CPUIDLE_NAME_LEN];
130 struct module *owner;
133 #ifdef CONFIG_CPU_IDLE
135 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
136 extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
137 extern int cpuidle_register_device(struct cpuidle_device *dev);
138 extern void cpuidle_unregister_device(struct cpuidle_device *dev);
140 extern void cpuidle_pause_and_lock(void);
141 extern void cpuidle_resume_and_unlock(void);
142 extern int cpuidle_enable_device(struct cpuidle_device *dev);
143 extern void cpuidle_disable_device(struct cpuidle_device *dev);
147 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
149 static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
150 static inline int cpuidle_register_device(struct cpuidle_device *dev)
152 static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
154 static inline void cpuidle_pause_and_lock(void) { }
155 static inline void cpuidle_resume_and_unlock(void) { }
156 static inline int cpuidle_enable_device(struct cpuidle_device *dev)
158 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
162 /******************************
163 * CPUIDLE GOVERNOR INTERFACE *
164 ******************************/
166 struct cpuidle_governor {
167 char name[CPUIDLE_NAME_LEN];
168 struct list_head governor_list;
171 int (*enable) (struct cpuidle_device *dev);
172 void (*disable) (struct cpuidle_device *dev);
174 int (*select) (struct cpuidle_device *dev);
175 void (*reflect) (struct cpuidle_device *dev);
177 struct module *owner;
180 #ifdef CONFIG_CPU_IDLE
182 extern int cpuidle_register_governor(struct cpuidle_governor *gov);
183 extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
187 static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
189 static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
193 #endif /* _LINUX_CPUIDLE_H */