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1 | /* |
2 | * Copyright (C) 2011 Google, Inc. |
3 | * |
4 | * Author: |
5 | * Colin Cross <ccross@android.com> |
6 | * |
7 | * This software is licensed under the terms of the GNU General Public |
8 | * License version 2, as published by the Free Software Foundation, and |
9 | * may be copied, distributed, and modified under those terms. |
10 | * |
11 | * This program is distributed in the hope that it will be useful, |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | * GNU General Public License for more details. |
15 | * |
16 | */ |
17 | |
18 | #include <linux/kernel.h> |
19 | #include <linux/cpu_pm.h> |
20 | #include <linux/module.h> |
21 | #include <linux/notifier.h> |
22 | #include <linux/spinlock.h> |
23 | #include <linux/syscore_ops.h> |
24 | |
25 | static DEFINE_RWLOCK(cpu_pm_notifier_lock); |
26 | static RAW_NOTIFIER_HEAD(cpu_pm_notifier_chain); |
27 | |
28 | static int cpu_pm_notify(enum cpu_pm_event event, int nr_to_call, int *nr_calls) |
29 | { |
30 | int ret; |
31 | |
32 | ret = __raw_notifier_call_chain(&cpu_pm_notifier_chain, event, NULL, |
33 | nr_to_call, nr_calls); |
34 | |
35 | return notifier_to_errno(ret); |
36 | } |
37 | |
38 | /** |
39 | * cpu_pm_register_notifier - register a driver with cpu_pm |
40 | * @nb: notifier block to register |
41 | * |
42 | * Add a driver to a list of drivers that are notified about |
43 | * CPU and CPU cluster low power entry and exit. |
44 | * |
45 | * This function may sleep, and has the same return conditions as |
46 | * raw_notifier_chain_register. |
47 | */ |
48 | int cpu_pm_register_notifier(struct notifier_block *nb) |
49 | { |
50 | unsigned long flags; |
51 | int ret; |
52 | |
53 | write_lock_irqsave(&cpu_pm_notifier_lock, flags); |
54 | ret = raw_notifier_chain_register(&cpu_pm_notifier_chain, nb); |
55 | write_unlock_irqrestore(&cpu_pm_notifier_lock, flags); |
56 | |
57 | return ret; |
58 | } |
59 | EXPORT_SYMBOL_GPL(cpu_pm_register_notifier); |
60 | |
61 | /** |
62 | * cpu_pm_unregister_notifier - unregister a driver with cpu_pm |
63 | * @nb: notifier block to be unregistered |
64 | * |
65 | * Remove a driver from the CPU PM notifier list. |
66 | * |
67 | * This function may sleep, and has the same return conditions as |
68 | * raw_notifier_chain_unregister. |
69 | */ |
70 | int cpu_pm_unregister_notifier(struct notifier_block *nb) |
71 | { |
72 | unsigned long flags; |
73 | int ret; |
74 | |
75 | write_lock_irqsave(&cpu_pm_notifier_lock, flags); |
76 | ret = raw_notifier_chain_unregister(&cpu_pm_notifier_chain, nb); |
77 | write_unlock_irqrestore(&cpu_pm_notifier_lock, flags); |
78 | |
79 | return ret; |
80 | } |
81 | EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier); |
82 | |
83 | /** |
84 | * cpm_pm_enter - CPU low power entry notifier |
85 | * |
86 | * Notifies listeners that a single CPU is entering a low power state that may |
87 | * cause some blocks in the same power domain as the cpu to reset. |
88 | * |
89 | * Must be called on the affected CPU with interrupts disabled. Platform is |
90 | * responsible for ensuring that cpu_pm_enter is not called twice on the same |
91 | * CPU before cpu_pm_exit is called. Notified drivers can include VFP |
92 | * co-processor, interrupt controller and it's PM extensions, local CPU |
93 | * timers context save/restore which shouldn't be interrupted. Hence it |
94 | * must be called with interrupts disabled. |
95 | * |
96 | * Return conditions are same as __raw_notifier_call_chain. |
97 | */ |
98 | int cpu_pm_enter(void) |
99 | { |
100 | int nr_calls; |
101 | int ret = 0; |
102 | |
103 | read_lock(&cpu_pm_notifier_lock); |
104 | ret = cpu_pm_notify(CPU_PM_ENTER, -1, &nr_calls); |
105 | if (ret) |
106 | /* |
107 | * Inform listeners (nr_calls - 1) about failure of CPU PM |
108 | * PM entry who are notified earlier to prepare for it. |
109 | */ |
110 | cpu_pm_notify(CPU_PM_ENTER_FAILED, nr_calls - 1, NULL); |
111 | read_unlock(&cpu_pm_notifier_lock); |
112 | |
113 | return ret; |
114 | } |
115 | EXPORT_SYMBOL_GPL(cpu_pm_enter); |
116 | |
117 | /** |
118 | * cpm_pm_exit - CPU low power exit notifier |
119 | * |
120 | * Notifies listeners that a single CPU is exiting a low power state that may |
121 | * have caused some blocks in the same power domain as the cpu to reset. |
122 | * |
123 | * Notified drivers can include VFP co-processor, interrupt controller |
124 | * and it's PM extensions, local CPU timers context save/restore which |
125 | * shouldn't be interrupted. Hence it must be called with interrupts disabled. |
126 | * |
127 | * Return conditions are same as __raw_notifier_call_chain. |
128 | */ |
129 | int cpu_pm_exit(void) |
130 | { |
131 | int ret; |
132 | |
133 | read_lock(&cpu_pm_notifier_lock); |
134 | ret = cpu_pm_notify(CPU_PM_EXIT, -1, NULL); |
135 | read_unlock(&cpu_pm_notifier_lock); |
136 | |
137 | return ret; |
138 | } |
139 | EXPORT_SYMBOL_GPL(cpu_pm_exit); |
140 | |
141 | /** |
142 | * cpm_cluster_pm_enter - CPU cluster low power entry notifier |
143 | * |
144 | * Notifies listeners that all cpus in a power domain are entering a low power |
145 | * state that may cause some blocks in the same power domain to reset. |
146 | * |
147 | * Must be called after cpu_pm_enter has been called on all cpus in the power |
148 | * domain, and before cpu_pm_exit has been called on any cpu in the power |
149 | * domain. Notified drivers can include VFP co-processor, interrupt controller |
150 | * and it's PM extensions, local CPU timers context save/restore which |
151 | * shouldn't be interrupted. Hence it must be called with interrupts disabled. |
152 | * |
153 | * Must be called with interrupts disabled. |
154 | * |
155 | * Return conditions are same as __raw_notifier_call_chain. |
156 | */ |
157 | int cpu_cluster_pm_enter(void) |
158 | { |
159 | int nr_calls; |
160 | int ret = 0; |
161 | |
162 | read_lock(&cpu_pm_notifier_lock); |
163 | ret = cpu_pm_notify(CPU_CLUSTER_PM_ENTER, -1, &nr_calls); |
164 | if (ret) |
165 | /* |
166 | * Inform listeners (nr_calls - 1) about failure of CPU cluster |
167 | * PM entry who are notified earlier to prepare for it. |
168 | */ |
169 | cpu_pm_notify(CPU_CLUSTER_PM_ENTER_FAILED, nr_calls - 1, NULL); |
170 | read_unlock(&cpu_pm_notifier_lock); |
171 | |
172 | return ret; |
173 | } |
174 | EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter); |
175 | |
176 | /** |
177 | * cpm_cluster_pm_exit - CPU cluster low power exit notifier |
178 | * |
179 | * Notifies listeners that all cpus in a power domain are exiting form a |
180 | * low power state that may have caused some blocks in the same power domain |
181 | * to reset. |
182 | * |
183 | * Must be called after cpu_pm_exit has been called on all cpus in the power |
184 | * domain, and before cpu_pm_exit has been called on any cpu in the power |
185 | * domain. Notified drivers can include VFP co-processor, interrupt controller |
186 | * and it's PM extensions, local CPU timers context save/restore which |
187 | * shouldn't be interrupted. Hence it must be called with interrupts disabled. |
188 | * |
189 | * Return conditions are same as __raw_notifier_call_chain. |
190 | */ |
191 | int cpu_cluster_pm_exit(void) |
192 | { |
193 | int ret; |
194 | |
195 | read_lock(&cpu_pm_notifier_lock); |
196 | ret = cpu_pm_notify(CPU_CLUSTER_PM_EXIT, -1, NULL); |
197 | read_unlock(&cpu_pm_notifier_lock); |
198 | |
199 | return ret; |
200 | } |
201 | EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit); |
202 | |
203 | #ifdef CONFIG_PM |
204 | static int cpu_pm_suspend(void) |
205 | { |
206 | int ret; |
207 | |
208 | ret = cpu_pm_enter(); |
209 | if (ret) |
210 | return ret; |
211 | |
212 | ret = cpu_cluster_pm_enter(); |
213 | return ret; |
214 | } |
215 | |
216 | static void cpu_pm_resume(void) |
217 | { |
218 | cpu_cluster_pm_exit(); |
219 | cpu_pm_exit(); |
220 | } |
221 | |
222 | static struct syscore_ops cpu_pm_syscore_ops = { |
223 | .suspend = cpu_pm_suspend, |
224 | .resume = cpu_pm_resume, |
225 | }; |
226 | |
227 | static int cpu_pm_init(void) |
228 | { |
229 | register_syscore_ops(&cpu_pm_syscore_ops); |
230 | return 0; |
231 | } |
232 | core_initcall(cpu_pm_init); |
233 | #endif |
234 |
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