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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#define CPUIDLE_FLAG_IGNORE (0x100) /* ignore during this idle period */
56#define CPUIDLE_FLAG_TLB_FLUSHED (0x200) /* tlb will be flushed */
57
58#define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
59
60/**
61 * cpuidle_get_statedata - retrieves private driver state data
62 * @state: the state
63 */
64static inline void * cpuidle_get_statedata(struct cpuidle_state *state)
65{
66 return state->driver_data;
67}
68
69/**
70 * cpuidle_set_statedata - stores private driver state data
71 * @state: the state
72 * @data: the private data
73 */
74static inline void
75cpuidle_set_statedata(struct cpuidle_state *state, void *data)
76{
77 state->driver_data = data;
78}
79
80struct cpuidle_state_kobj {
81 struct cpuidle_state *state;
82 struct completion kobj_unregister;
83 struct kobject kobj;
84};
85
86struct cpuidle_device {
87 unsigned int registered:1;
88 unsigned int enabled:1;
89 unsigned int power_specified:1;
90 unsigned int cpu;
91
92 int last_residency;
93 int state_count;
94 struct cpuidle_state states[CPUIDLE_STATE_MAX];
95 struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
96 struct cpuidle_state *last_state;
97
98 struct list_head device_list;
99 struct kobject kobj;
100 struct completion kobj_unregister;
101 void *governor_data;
102 struct cpuidle_state *safe_state;
103
104 int (*prepare) (struct cpuidle_device *dev);
105};
106
107DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
108
109/**
110 * cpuidle_get_last_residency - retrieves the last state's residency time
111 * @dev: the target CPU
112 *
113 * NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
114 */
115static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
116{
117 return dev->last_residency;
118}
119
120
121/****************************
122 * CPUIDLE DRIVER INTERFACE *
123 ****************************/
124
125struct cpuidle_driver {
126 char name[CPUIDLE_NAME_LEN];
127 struct module *owner;
128};
129
130#ifdef CONFIG_CPU_IDLE
131
132extern int cpuidle_register_driver(struct cpuidle_driver *drv);
133struct cpuidle_driver *cpuidle_get_driver(void);
134extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
135extern int cpuidle_register_device(struct cpuidle_device *dev);
136extern void cpuidle_unregister_device(struct cpuidle_device *dev);
137
138extern void cpuidle_pause_and_lock(void);
139extern void cpuidle_resume_and_unlock(void);
140extern int cpuidle_enable_device(struct cpuidle_device *dev);
141extern void cpuidle_disable_device(struct cpuidle_device *dev);
142
143#else
144
145static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
146{return -ENODEV; }
147static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
148static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
149static inline int cpuidle_register_device(struct cpuidle_device *dev)
150{return -ENODEV; }
151static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
152
153static inline void cpuidle_pause_and_lock(void) { }
154static inline void cpuidle_resume_and_unlock(void) { }
155static inline int cpuidle_enable_device(struct cpuidle_device *dev)
156{return -ENODEV; }
157static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
158
159#endif
160
161/******************************
162 * CPUIDLE GOVERNOR INTERFACE *
163 ******************************/
164
165struct cpuidle_governor {
166 char name[CPUIDLE_NAME_LEN];
167 struct list_head governor_list;
168 unsigned int rating;
169
170 int (*enable) (struct cpuidle_device *dev);
171 void (*disable) (struct cpuidle_device *dev);
172
173 int (*select) (struct cpuidle_device *dev);
174 void (*reflect) (struct cpuidle_device *dev);
175
176 struct module *owner;
177};
178
179#ifdef CONFIG_CPU_IDLE
180
181extern int cpuidle_register_governor(struct cpuidle_governor *gov);
182extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
183
184#else
185
186static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
187{return 0;}
188static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
189
190#endif
191
192#ifdef CONFIG_ARCH_HAS_CPU_RELAX
193#define CPUIDLE_DRIVER_STATE_START 1
194#else
195#define CPUIDLE_DRIVER_STATE_START 0
196#endif
197
198#endif /* _LINUX_CPUIDLE_H */