1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2011 Google, Inc.
*
* Author:
* Colin Cross <ccross@android.com>
*/
#include <linux/kernel.h>
#include <linux/cpu_pm.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/spinlock.h>
#include <linux/syscore_ops.h>
/*
* atomic_notifiers use a spinlock_t, which can block under PREEMPT_RT.
* Notifications for cpu_pm will be issued by the idle task itself, which can
* never block, IOW it requires using a raw_spinlock_t.
*/
static struct {
struct raw_notifier_head chain;
raw_spinlock_t lock;
} cpu_pm_notifier = {
.chain = RAW_NOTIFIER_INIT(cpu_pm_notifier.chain),
.lock = __RAW_SPIN_LOCK_UNLOCKED(cpu_pm_notifier.lock),
};
static int cpu_pm_notify(enum cpu_pm_event event)
{
int ret;
rcu_read_lock();
ret = raw_notifier_call_chain(&cpu_pm_notifier.chain, event, NULL);
rcu_read_unlock();
return notifier_to_errno(ret);
}
static int cpu_pm_notify_robust(enum cpu_pm_event event_up, enum cpu_pm_event event_down)
{
unsigned long flags;
int ret;
raw_spin_lock_irqsave(&cpu_pm_notifier.lock, flags);
ret = raw_notifier_call_chain_robust(&cpu_pm_notifier.chain, event_up, event_down, NULL);
raw_spin_unlock_irqrestore(&cpu_pm_notifier.lock, flags);
return notifier_to_errno(ret);
}
/**
* cpu_pm_register_notifier - register a driver with cpu_pm
* @nb: notifier block to register
*
* Add a driver to a list of drivers that are notified about
* CPU and CPU cluster low power entry and exit.
*
* This function has the same return conditions as raw_notifier_chain_register.
*/
int cpu_pm_register_notifier(struct notifier_block *nb)
{
unsigned long flags;
int ret;
raw_spin_lock_irqsave(&cpu_pm_notifier.lock, flags);
ret = raw_notifier_chain_register(&cpu_pm_notifier.chain, nb);
raw_spin_unlock_irqrestore(&cpu_pm_notifier.lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(cpu_pm_register_notifier);
/**
* cpu_pm_unregister_notifier - unregister a driver with cpu_pm
* @nb: notifier block to be unregistered
*
* Remove a driver from the CPU PM notifier list.
*
* This function has the same return conditions as raw_notifier_chain_unregister.
*/
int cpu_pm_unregister_notifier(struct notifier_block *nb)
{
unsigned long flags;
int ret;
raw_spin_lock_irqsave(&cpu_pm_notifier.lock, flags);
ret = raw_notifier_chain_unregister(&cpu_pm_notifier.chain, nb);
raw_spin_unlock_irqrestore(&cpu_pm_notifier.lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier);
/**
* cpu_pm_enter - CPU low power entry notifier
*
* Notifies listeners that a single CPU is entering a low power state that may
* cause some blocks in the same power domain as the cpu to reset.
*
* Must be called on the affected CPU with interrupts disabled. Platform is
* responsible for ensuring that cpu_pm_enter is not called twice on the same
* CPU before cpu_pm_exit is called. Notified drivers can include VFP
* co-processor, interrupt controller and its PM extensions, local CPU
* timers context save/restore which shouldn't be interrupted. Hence it
* must be called with interrupts disabled.
*
* Return conditions are same as __raw_notifier_call_chain.
*/
int cpu_pm_enter(void)
{
return cpu_pm_notify_robust(CPU_PM_ENTER, CPU_PM_ENTER_FAILED);
}
EXPORT_SYMBOL_GPL(cpu_pm_enter);
/**
* cpu_pm_exit - CPU low power exit notifier
*
* Notifies listeners that a single CPU is exiting a low power state that may
* have caused some blocks in the same power domain as the cpu to reset.
*
* Notified drivers can include VFP co-processor, interrupt controller
* and its PM extensions, local CPU timers context save/restore which
* shouldn't be interrupted. Hence it must be called with interrupts disabled.
*
* Return conditions are same as __raw_notifier_call_chain.
*/
int cpu_pm_exit(void)
{
return cpu_pm_notify(CPU_PM_EXIT);
}
EXPORT_SYMBOL_GPL(cpu_pm_exit);
/**
* cpu_cluster_pm_enter - CPU cluster low power entry notifier
*
* Notifies listeners that all cpus in a power domain are entering a low power
* state that may cause some blocks in the same power domain to reset.
*
* Must be called after cpu_pm_enter has been called on all cpus in the power
* domain, and before cpu_pm_exit has been called on any cpu in the power
* domain. Notified drivers can include VFP co-processor, interrupt controller
* and its PM extensions, local CPU timers context save/restore which
* shouldn't be interrupted. Hence it must be called with interrupts disabled.
*
* Must be called with interrupts disabled.
*
* Return conditions are same as __raw_notifier_call_chain.
*/
int cpu_cluster_pm_enter(void)
{
return cpu_pm_notify_robust(CPU_CLUSTER_PM_ENTER, CPU_CLUSTER_PM_ENTER_FAILED);
}
EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter);
/**
* cpu_cluster_pm_exit - CPU cluster low power exit notifier
*
* Notifies listeners that all cpus in a power domain are exiting form a
* low power state that may have caused some blocks in the same power domain
* to reset.
*
* Must be called after cpu_cluster_pm_enter has been called for the power
* domain, and before cpu_pm_exit has been called on any cpu in the power
* domain. Notified drivers can include VFP co-processor, interrupt controller
* and its PM extensions, local CPU timers context save/restore which
* shouldn't be interrupted. Hence it must be called with interrupts disabled.
*
* Return conditions are same as __raw_notifier_call_chain.
*/
int cpu_cluster_pm_exit(void)
{
return cpu_pm_notify(CPU_CLUSTER_PM_EXIT);
}
EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit);
#ifdef CONFIG_PM
static int cpu_pm_suspend(void)
{
int ret;
ret = cpu_pm_enter();
if (ret)
return ret;
ret = cpu_cluster_pm_enter();
return ret;
}
static void cpu_pm_resume(void)
{
cpu_cluster_pm_exit();
cpu_pm_exit();
}
static struct syscore_ops cpu_pm_syscore_ops = {
.suspend = cpu_pm_suspend,
.resume = cpu_pm_resume,
};
static int cpu_pm_init(void)
{
register_syscore_ops(&cpu_pm_syscore_ops);
return 0;
}
core_initcall(cpu_pm_init);
#endif
|
