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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
24struct cpuidle_device;
25
26
27/****************************
28 * CPUIDLE DEVICE INTERFACE *
29 ****************************/
30
31struct 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 */
62static 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 */
72static inline void
73cpuidle_set_statedata(struct cpuidle_state *state, void *data)
74{
75 state->driver_data = data;
76}
77
78struct cpuidle_state_kobj {
79 struct cpuidle_state *state;
80 struct completion kobj_unregister;
81 struct kobject kobj;
82};
83
84struct 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
102DECLARE_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 */
110static 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
120struct cpuidle_driver {
121 char name[CPUIDLE_NAME_LEN];
122 struct module *owner;
123};
124
125#ifdef CONFIG_CPU_IDLE
126
127extern int cpuidle_register_driver(struct cpuidle_driver *drv);
128struct cpuidle_driver *cpuidle_get_driver(void);
129extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
130extern int cpuidle_register_device(struct cpuidle_device *dev);
131extern void cpuidle_unregister_device(struct cpuidle_device *dev);
132
133extern void cpuidle_pause_and_lock(void);
134extern void cpuidle_resume_and_unlock(void);
135extern int cpuidle_enable_device(struct cpuidle_device *dev);
136extern void cpuidle_disable_device(struct cpuidle_device *dev);
137
138#else
139
140static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
141{return -ENODEV; }
142static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
143static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
144static inline int cpuidle_register_device(struct cpuidle_device *dev)
145{return -ENODEV; }
146static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
147
148static inline void cpuidle_pause_and_lock(void) { }
149static inline void cpuidle_resume_and_unlock(void) { }
150static inline int cpuidle_enable_device(struct cpuidle_device *dev)
151{return -ENODEV; }
152static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
153
154#endif
155
156/******************************
157 * CPUIDLE GOVERNOR INTERFACE *
158 ******************************/
159
160struct 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
176extern int cpuidle_register_governor(struct cpuidle_governor *gov);
177extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
178
179#else
180
181static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
182{return 0;}
183static 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 */