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-rw-r--r--include/linux/cpu_pm.h109
-rw-r--r--kernel/Makefile1
-rw-r--r--kernel/cpu_pm.c200
-rw-r--r--kernel/power/Kconfig4
4 files changed, 314 insertions, 0 deletions
diff --git a/include/linux/cpu_pm.h b/include/linux/cpu_pm.h
new file mode 100644
index 000000000000..455b233dd3b1
--- /dev/null
+++ b/include/linux/cpu_pm.h
@@ -0,0 +1,109 @@
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#ifndef _LINUX_CPU_PM_H
19#define _LINUX_CPU_PM_H
20
21#include <linux/kernel.h>
22#include <linux/notifier.h>
23
24/*
25 * When a CPU goes to a low power state that turns off power to the CPU's
26 * power domain, the contents of some blocks (floating point coprocessors,
27 * interrupt controllers, caches, timers) in the same power domain can
28 * be lost. The cpm_pm notifiers provide a method for platform idle, suspend,
29 * and hotplug implementations to notify the drivers for these blocks that
30 * they may be reset.
31 *
32 * All cpu_pm notifications must be called with interrupts disabled.
33 *
34 * The notifications are split into two classes: CPU notifications and CPU
35 * cluster notifications.
36 *
37 * CPU notifications apply to a single CPU and must be called on the affected
38 * CPU. They are used to save per-cpu context for affected blocks.
39 *
40 * CPU cluster notifications apply to all CPUs in a single power domain. They
41 * are used to save any global context for affected blocks, and must be called
42 * after all the CPUs in the power domain have been notified of the low power
43 * state.
44 */
45
46/*
47 * Event codes passed as unsigned long val to notifier calls
48 */
49enum cpu_pm_event {
50 /* A single cpu is entering a low power state */
51 CPU_PM_ENTER,
52
53 /* A single cpu failed to enter a low power state */
54 CPU_PM_ENTER_FAILED,
55
56 /* A single cpu is exiting a low power state */
57 CPU_PM_EXIT,
58
59 /* A cpu power domain is entering a low power state */
60 CPU_CLUSTER_PM_ENTER,
61
62 /* A cpu power domain failed to enter a low power state */
63 CPU_CLUSTER_PM_ENTER_FAILED,
64
65 /* A cpu power domain is exiting a low power state */
66 CPU_CLUSTER_PM_EXIT,
67};
68
69#ifdef CONFIG_CPU_PM
70int cpu_pm_register_notifier(struct notifier_block *nb);
71int cpu_pm_unregister_notifier(struct notifier_block *nb);
72int cpu_pm_enter(void);
73int cpu_pm_exit(void);
74int cpu_cluster_pm_enter(void);
75int cpu_cluster_pm_exit(void);
76
77#else
78
79static inline int cpu_pm_register_notifier(struct notifier_block *nb)
80{
81 return 0;
82}
83
84static inline int cpu_pm_unregister_notifier(struct notifier_block *nb)
85{
86 return 0;
87}
88
89static inline int cpu_pm_enter(void)
90{
91 return 0;
92}
93
94static inline int cpu_pm_exit(void)
95{
96 return 0;
97}
98
99static inline int cpu_cluster_pm_enter(void)
100{
101 return 0;
102}
103
104static inline int cpu_cluster_pm_exit(void)
105{
106 return 0;
107}
108#endif
109#endif
diff --git a/kernel/Makefile b/kernel/Makefile
index eca595e2fd52..988cb3da7031 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -101,6 +101,7 @@ obj-$(CONFIG_RING_BUFFER) += trace/
101obj-$(CONFIG_TRACEPOINTS) += trace/ 101obj-$(CONFIG_TRACEPOINTS) += trace/
102obj-$(CONFIG_SMP) += sched_cpupri.o 102obj-$(CONFIG_SMP) += sched_cpupri.o
103obj-$(CONFIG_IRQ_WORK) += irq_work.o 103obj-$(CONFIG_IRQ_WORK) += irq_work.o
104obj-$(CONFIG_CPU_PM) += cpu_pm.o
104 105
105obj-$(CONFIG_PERF_EVENTS) += events/ 106obj-$(CONFIG_PERF_EVENTS) += events/
106 107
diff --git a/kernel/cpu_pm.c b/kernel/cpu_pm.c
new file mode 100644
index 000000000000..4d1ff4acd04b
--- /dev/null
+++ b/kernel/cpu_pm.c
@@ -0,0 +1,200 @@
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
24static DEFINE_RWLOCK(cpu_pm_notifier_lock);
25static RAW_NOTIFIER_HEAD(cpu_pm_notifier_chain);
26
27static 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 */
47int 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}
58EXPORT_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 */
69int 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}
80EXPORT_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 */
97int 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}
114EXPORT_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 */
128int 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}
138EXPORT_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 */
156int 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}
173EXPORT_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 */
190int 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}
200EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit);
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 3744c594b19b..80a85971cf64 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -235,3 +235,7 @@ config PM_GENERIC_DOMAINS
235config PM_GENERIC_DOMAINS_RUNTIME 235config PM_GENERIC_DOMAINS_RUNTIME
236 def_bool y 236 def_bool y
237 depends on PM_RUNTIME && PM_GENERIC_DOMAINS 237 depends on PM_RUNTIME && PM_GENERIC_DOMAINS
238
239config CPU_PM
240 bool
241 depends on SUSPEND || CPU_IDLE