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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 | ||
24 | static DEFINE_RWLOCK(cpu_pm_notifier_lock); | |
25 | static RAW_NOTIFIER_HEAD(cpu_pm_notifier_chain); | |
26 | ||
27 | static int cpu_pm_notify(enum cpu_pm_event event, int nr_to_call, int *nr_calls) | |
28 | { | |
29 | int ret; | |
30 | ||
31 | ret = __raw_notifier_call_chain(&cpu_pm_notifier_chain, event, NULL, | |
32 | nr_to_call, nr_calls); | |
33 | ||
34 | return notifier_to_errno(ret); | |
35 | } | |
36 | ||
37 | /** | |
38 | * cpu_pm_register_notifier - register a driver with cpu_pm | |
39 | * @nb: notifier block to register | |
40 | * | |
41 | * Add a driver to a list of drivers that are notified about | |
42 | * CPU and CPU cluster low power entry and exit. | |
43 | * | |
44 | * This function may sleep, and has the same return conditions as | |
45 | * raw_notifier_chain_register. | |
46 | */ | |
47 | int cpu_pm_register_notifier(struct notifier_block *nb) | |
48 | { | |
49 | unsigned long flags; | |
50 | int ret; | |
51 | ||
52 | write_lock_irqsave(&cpu_pm_notifier_lock, flags); | |
53 | ret = raw_notifier_chain_register(&cpu_pm_notifier_chain, nb); | |
54 | write_unlock_irqrestore(&cpu_pm_notifier_lock, flags); | |
55 | ||
56 | return ret; | |
57 | } | |
58 | EXPORT_SYMBOL_GPL(cpu_pm_register_notifier); | |
59 | ||
60 | /** | |
61 | * cpu_pm_unregister_notifier - unregister a driver with cpu_pm | |
62 | * @nb: notifier block to be unregistered | |
63 | * | |
64 | * Remove a driver from the CPU PM notifier list. | |
65 | * | |
66 | * This function may sleep, and has the same return conditions as | |
67 | * raw_notifier_chain_unregister. | |
68 | */ | |
69 | int cpu_pm_unregister_notifier(struct notifier_block *nb) | |
70 | { | |
71 | unsigned long flags; | |
72 | int ret; | |
73 | ||
74 | write_lock_irqsave(&cpu_pm_notifier_lock, flags); | |
75 | ret = raw_notifier_chain_unregister(&cpu_pm_notifier_chain, nb); | |
76 | write_unlock_irqrestore(&cpu_pm_notifier_lock, flags); | |
77 | ||
78 | return ret; | |
79 | } | |
80 | EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier); | |
81 | ||
82 | /** | |
83 | * cpm_pm_enter - CPU low power entry notifier | |
84 | * | |
85 | * Notifies listeners that a single CPU is entering a low power state that may | |
86 | * cause some blocks in the same power domain as the cpu to reset. | |
87 | * | |
88 | * Must be called on the affected CPU with interrupts disabled. Platform is | |
89 | * responsible for ensuring that cpu_pm_enter is not called twice on the same | |
90 | * CPU before cpu_pm_exit is called. Notified drivers can include VFP | |
91 | * co-processor, interrupt controller and it's PM extensions, local CPU | |
92 | * timers context save/restore which shouldn't be interrupted. Hence it | |
93 | * must be called with interrupts disabled. | |
94 | * | |
95 | * Return conditions are same as __raw_notifier_call_chain. | |
96 | */ | |
97 | int cpu_pm_enter(void) | |
98 | { | |
99 | int nr_calls; | |
100 | int ret = 0; | |
101 | ||
102 | read_lock(&cpu_pm_notifier_lock); | |
103 | ret = cpu_pm_notify(CPU_PM_ENTER, -1, &nr_calls); | |
104 | if (ret) | |
105 | /* | |
106 | * Inform listeners (nr_calls - 1) about failure of CPU PM | |
107 | * PM entry who are notified earlier to prepare for it. | |
108 | */ | |
109 | cpu_pm_notify(CPU_PM_ENTER_FAILED, nr_calls - 1, NULL); | |
110 | read_unlock(&cpu_pm_notifier_lock); | |
111 | ||
112 | return ret; | |
113 | } | |
114 | EXPORT_SYMBOL_GPL(cpu_pm_enter); | |
115 | ||
116 | /** | |
117 | * cpm_pm_exit - CPU low power exit notifier | |
118 | * | |
119 | * Notifies listeners that a single CPU is exiting a low power state that may | |
120 | * have caused some blocks in the same power domain as the cpu to reset. | |
121 | * | |
122 | * Notified drivers can include VFP co-processor, interrupt controller | |
123 | * and it's PM extensions, local CPU timers context save/restore which | |
124 | * shouldn't be interrupted. Hence it must be called with interrupts disabled. | |
125 | * | |
126 | * Return conditions are same as __raw_notifier_call_chain. | |
127 | */ | |
128 | int cpu_pm_exit(void) | |
129 | { | |
130 | int ret; | |
131 | ||
132 | read_lock(&cpu_pm_notifier_lock); | |
133 | ret = cpu_pm_notify(CPU_PM_EXIT, -1, NULL); | |
134 | read_unlock(&cpu_pm_notifier_lock); | |
135 | ||
136 | return ret; | |
137 | } | |
138 | EXPORT_SYMBOL_GPL(cpu_pm_exit); | |
139 | ||
140 | /** | |
141 | * cpm_cluster_pm_enter - CPU cluster low power entry notifier | |
142 | * | |
143 | * Notifies listeners that all cpus in a power domain are entering a low power | |
144 | * state that may cause some blocks in the same power domain to reset. | |
145 | * | |
146 | * Must be called after cpu_pm_enter has been called on all cpus in the power | |
147 | * domain, and before cpu_pm_exit has been called on any cpu in the power | |
148 | * domain. Notified drivers can include VFP co-processor, interrupt controller | |
149 | * and it's PM extensions, local CPU timers context save/restore which | |
150 | * shouldn't be interrupted. Hence it must be called with interrupts disabled. | |
151 | * | |
152 | * Must be called with interrupts disabled. | |
153 | * | |
154 | * Return conditions are same as __raw_notifier_call_chain. | |
155 | */ | |
156 | int cpu_cluster_pm_enter(void) | |
157 | { | |
158 | int nr_calls; | |
159 | int ret = 0; | |
160 | ||
161 | read_lock(&cpu_pm_notifier_lock); | |
162 | ret = cpu_pm_notify(CPU_CLUSTER_PM_ENTER, -1, &nr_calls); | |
163 | if (ret) | |
164 | /* | |
165 | * Inform listeners (nr_calls - 1) about failure of CPU cluster | |
166 | * PM entry who are notified earlier to prepare for it. | |
167 | */ | |
168 | cpu_pm_notify(CPU_CLUSTER_PM_ENTER_FAILED, nr_calls - 1, NULL); | |
169 | read_unlock(&cpu_pm_notifier_lock); | |
170 | ||
171 | return ret; | |
172 | } | |
173 | EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter); | |
174 | ||
175 | /** | |
176 | * cpm_cluster_pm_exit - CPU cluster low power exit notifier | |
177 | * | |
178 | * Notifies listeners that all cpus in a power domain are exiting form a | |
179 | * low power state that may have caused some blocks in the same power domain | |
180 | * to reset. | |
181 | * | |
182 | * Must be called after cpu_pm_exit has been called on all cpus in the power | |
183 | * domain, and before cpu_pm_exit has been called on any cpu in the power | |
184 | * domain. Notified drivers can include VFP co-processor, interrupt controller | |
185 | * and it's PM extensions, local CPU timers context save/restore which | |
186 | * shouldn't be interrupted. Hence it must be called with interrupts disabled. | |
187 | * | |
188 | * Return conditions are same as __raw_notifier_call_chain. | |
189 | */ | |
190 | int cpu_cluster_pm_exit(void) | |
191 | { | |
192 | int ret; | |
193 | ||
194 | read_lock(&cpu_pm_notifier_lock); | |
195 | ret = cpu_pm_notify(CPU_CLUSTER_PM_EXIT, -1, NULL); | |
196 | read_unlock(&cpu_pm_notifier_lock); | |
197 | ||
198 | return ret; | |
199 | } | |
200 | EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit); |