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_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 */
54 #define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
57 * cpuidle_get_statedata - retrieves private driver state data
60 static inline void * cpuidle_get_statedata(struct cpuidle_state *state)
62 return state->driver_data;
66 * cpuidle_set_statedata - stores private driver state data
68 * @data: the private data
71 cpuidle_set_statedata(struct cpuidle_state *state, void *data)
73 state->driver_data = data;
77 #ifdef CONFIG_ARCH_HAS_CPU_IDLE_WAIT
78 static inline void cpuidle_kick_cpus(void)
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 */
89 struct cpuidle_state_kobj {
90 struct cpuidle_state *state;
91 struct completion kobj_unregister;
95 struct cpuidle_device {
96 unsigned int enabled:1;
101 struct cpuidle_state states[CPUIDLE_STATE_MAX];
102 struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
103 struct cpuidle_state *last_state;
105 struct list_head device_list;
107 struct completion kobj_unregister;
109 struct cpuidle_state *safe_state;
112 DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
115 * cpuidle_get_last_residency - retrieves the last state's residency time
116 * @dev: the target CPU
118 * NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
120 static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
122 return dev->last_residency;
126 /****************************
127 * CPUIDLE DRIVER INTERFACE *
128 ****************************/
130 struct cpuidle_driver {
131 char name[CPUIDLE_NAME_LEN];
132 struct module *owner;
135 #ifdef CONFIG_CPU_IDLE
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);
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);
149 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
151 static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
152 static inline int cpuidle_register_device(struct cpuidle_device *dev)
154 static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
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)
160 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
164 /******************************
165 * CPUIDLE GOVERNOR INTERFACE *
166 ******************************/
168 struct cpuidle_governor {
169 char name[CPUIDLE_NAME_LEN];
170 struct list_head governor_list;
173 int (*enable) (struct cpuidle_device *dev);
174 void (*disable) (struct cpuidle_device *dev);
176 int (*select) (struct cpuidle_device *dev);
177 void (*reflect) (struct cpuidle_device *dev);
179 struct module *owner;
182 #ifdef CONFIG_CPU_IDLE
184 extern int cpuidle_register_governor(struct cpuidle_governor *gov);
185 extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
189 static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
191 static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
195 #ifdef CONFIG_ARCH_HAS_CPU_RELAX
196 #define CPUIDLE_DRIVER_STATE_START 1
198 #define CPUIDLE_DRIVER_STATE_START 0
201 #endif /* _LINUX_CPUIDLE_H */