1 // SPDX-License-Identifier: GPL-2.0-only 1 // SPDX-License-Identifier: GPL-2.0-only
2 /* 2 /*
3 * Copyright (C) 2011 Google, Inc. 3 * Copyright (C) 2011 Google, Inc.
4 * 4 *
5 * Author: 5 * Author:
6 * Colin Cross <ccross@android.com> 6 * Colin Cross <ccross@android.com>
7 */ 7 */
8 8
9 #include <linux/kernel.h> 9 #include <linux/kernel.h>
10 #include <linux/cpu_pm.h> 10 #include <linux/cpu_pm.h>
11 #include <linux/module.h> 11 #include <linux/module.h>
12 #include <linux/notifier.h> 12 #include <linux/notifier.h>
13 #include <linux/spinlock.h> 13 #include <linux/spinlock.h>
14 #include <linux/syscore_ops.h> 14 #include <linux/syscore_ops.h>
15 15
16 /* !! 16 static ATOMIC_NOTIFIER_HEAD(cpu_pm_notifier_chain);
17 * atomic_notifiers use a spinlock_t, which ca <<
18 * Notifications for cpu_pm will be issued by <<
19 * never block, IOW it requires using a raw_sp <<
20 */ <<
21 static struct { <<
22 struct raw_notifier_head chain; <<
23 raw_spinlock_t lock; <<
24 } cpu_pm_notifier = { <<
25 .chain = RAW_NOTIFIER_INIT(cpu_pm_noti <<
26 .lock = __RAW_SPIN_LOCK_UNLOCKED(cpu_ <<
27 }; <<
28 17
29 static int cpu_pm_notify(enum cpu_pm_event eve !! 18 static int cpu_pm_notify(enum cpu_pm_event event, int nr_to_call, int *nr_calls)
30 { 19 {
31 int ret; 20 int ret;
32 21
33 rcu_read_lock(); !! 22 /*
34 ret = raw_notifier_call_chain(&cpu_pm_ !! 23 * __atomic_notifier_call_chain has a RCU read critical section, which
35 rcu_read_unlock(); !! 24 * could be disfunctional in cpu idle. Copy RCU_NONIDLE code to let
36 !! 25 * RCU know this.
37 return notifier_to_errno(ret); !! 26 */
38 } !! 27 rcu_irq_enter_irqson();
39 !! 28 ret = __atomic_notifier_call_chain(&cpu_pm_notifier_chain, event, NULL,
40 static int cpu_pm_notify_robust(enum cpu_pm_ev !! 29 nr_to_call, nr_calls);
41 { !! 30 rcu_irq_exit_irqson();
42 unsigned long flags; <<
43 int ret; <<
44 <<
45 raw_spin_lock_irqsave(&cpu_pm_notifier <<
46 ret = raw_notifier_call_chain_robust(& <<
47 raw_spin_unlock_irqrestore(&cpu_pm_not <<
48 31
49 return notifier_to_errno(ret); 32 return notifier_to_errno(ret);
50 } 33 }
51 34
52 /** 35 /**
53 * cpu_pm_register_notifier - register a drive 36 * cpu_pm_register_notifier - register a driver with cpu_pm
54 * @nb: notifier block to register 37 * @nb: notifier block to register
55 * 38 *
56 * Add a driver to a list of drivers that are 39 * Add a driver to a list of drivers that are notified about
57 * CPU and CPU cluster low power entry and exi 40 * CPU and CPU cluster low power entry and exit.
58 * 41 *
59 * This function has the same return condition !! 42 * This function may sleep, and has the same return conditions as
>> 43 * raw_notifier_chain_register.
60 */ 44 */
61 int cpu_pm_register_notifier(struct notifier_b 45 int cpu_pm_register_notifier(struct notifier_block *nb)
62 { 46 {
63 unsigned long flags; !! 47 return atomic_notifier_chain_register(&cpu_pm_notifier_chain, nb);
64 int ret; <<
65 <<
66 raw_spin_lock_irqsave(&cpu_pm_notifier <<
67 ret = raw_notifier_chain_register(&cpu <<
68 raw_spin_unlock_irqrestore(&cpu_pm_not <<
69 return ret; <<
70 } 48 }
71 EXPORT_SYMBOL_GPL(cpu_pm_register_notifier); 49 EXPORT_SYMBOL_GPL(cpu_pm_register_notifier);
72 50
73 /** 51 /**
74 * cpu_pm_unregister_notifier - unregister a d 52 * cpu_pm_unregister_notifier - unregister a driver with cpu_pm
75 * @nb: notifier block to be unregistered 53 * @nb: notifier block to be unregistered
76 * 54 *
77 * Remove a driver from the CPU PM notifier li 55 * Remove a driver from the CPU PM notifier list.
78 * 56 *
79 * This function has the same return condition !! 57 * This function may sleep, and has the same return conditions as
>> 58 * raw_notifier_chain_unregister.
80 */ 59 */
81 int cpu_pm_unregister_notifier(struct notifier 60 int cpu_pm_unregister_notifier(struct notifier_block *nb)
82 { 61 {
83 unsigned long flags; !! 62 return atomic_notifier_chain_unregister(&cpu_pm_notifier_chain, nb);
84 int ret; <<
85 <<
86 raw_spin_lock_irqsave(&cpu_pm_notifier <<
87 ret = raw_notifier_chain_unregister(&c <<
88 raw_spin_unlock_irqrestore(&cpu_pm_not <<
89 return ret; <<
90 } 63 }
91 EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier); 64 EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier);
92 65
93 /** 66 /**
94 * cpu_pm_enter - CPU low power entry notifier 67 * cpu_pm_enter - CPU low power entry notifier
95 * 68 *
96 * Notifies listeners that a single CPU is ent 69 * Notifies listeners that a single CPU is entering a low power state that may
97 * cause some blocks in the same power domain 70 * cause some blocks in the same power domain as the cpu to reset.
98 * 71 *
99 * Must be called on the affected CPU with int 72 * Must be called on the affected CPU with interrupts disabled. Platform is
100 * responsible for ensuring that cpu_pm_enter 73 * responsible for ensuring that cpu_pm_enter is not called twice on the same
101 * CPU before cpu_pm_exit is called. Notified 74 * CPU before cpu_pm_exit is called. Notified drivers can include VFP
102 * co-processor, interrupt controller and its 75 * co-processor, interrupt controller and its PM extensions, local CPU
103 * timers context save/restore which shouldn't 76 * timers context save/restore which shouldn't be interrupted. Hence it
104 * must be called with interrupts disabled. 77 * must be called with interrupts disabled.
105 * 78 *
106 * Return conditions are same as __raw_notifie 79 * Return conditions are same as __raw_notifier_call_chain.
107 */ 80 */
108 int cpu_pm_enter(void) 81 int cpu_pm_enter(void)
109 { 82 {
110 return cpu_pm_notify_robust(CPU_PM_ENT !! 83 int nr_calls = 0;
>> 84 int ret = 0;
>> 85
>> 86 ret = cpu_pm_notify(CPU_PM_ENTER, -1, &nr_calls);
>> 87 if (ret)
>> 88 /*
>> 89 * Inform listeners (nr_calls - 1) about failure of CPU PM
>> 90 * PM entry who are notified earlier to prepare for it.
>> 91 */
>> 92 cpu_pm_notify(CPU_PM_ENTER_FAILED, nr_calls - 1, NULL);
>> 93
>> 94 return ret;
111 } 95 }
112 EXPORT_SYMBOL_GPL(cpu_pm_enter); 96 EXPORT_SYMBOL_GPL(cpu_pm_enter);
113 97
114 /** 98 /**
115 * cpu_pm_exit - CPU low power exit notifier 99 * cpu_pm_exit - CPU low power exit notifier
116 * 100 *
117 * Notifies listeners that a single CPU is exi 101 * Notifies listeners that a single CPU is exiting a low power state that may
118 * have caused some blocks in the same power d 102 * have caused some blocks in the same power domain as the cpu to reset.
119 * 103 *
120 * Notified drivers can include VFP co-process 104 * Notified drivers can include VFP co-processor, interrupt controller
121 * and its PM extensions, local CPU timers con 105 * and its PM extensions, local CPU timers context save/restore which
122 * shouldn't be interrupted. Hence it must be 106 * shouldn't be interrupted. Hence it must be called with interrupts disabled.
123 * 107 *
124 * Return conditions are same as __raw_notifie 108 * Return conditions are same as __raw_notifier_call_chain.
125 */ 109 */
126 int cpu_pm_exit(void) 110 int cpu_pm_exit(void)
127 { 111 {
128 return cpu_pm_notify(CPU_PM_EXIT); !! 112 return cpu_pm_notify(CPU_PM_EXIT, -1, NULL);
129 } 113 }
130 EXPORT_SYMBOL_GPL(cpu_pm_exit); 114 EXPORT_SYMBOL_GPL(cpu_pm_exit);
131 115
132 /** 116 /**
133 * cpu_cluster_pm_enter - CPU cluster low powe 117 * cpu_cluster_pm_enter - CPU cluster low power entry notifier
134 * 118 *
135 * Notifies listeners that all cpus in a power 119 * Notifies listeners that all cpus in a power domain are entering a low power
136 * state that may cause some blocks in the sam 120 * state that may cause some blocks in the same power domain to reset.
137 * 121 *
138 * Must be called after cpu_pm_enter has been 122 * Must be called after cpu_pm_enter has been called on all cpus in the power
139 * domain, and before cpu_pm_exit has been cal 123 * domain, and before cpu_pm_exit has been called on any cpu in the power
140 * domain. Notified drivers can include VFP co 124 * domain. Notified drivers can include VFP co-processor, interrupt controller
141 * and its PM extensions, local CPU timers con 125 * and its PM extensions, local CPU timers context save/restore which
142 * shouldn't be interrupted. Hence it must be 126 * shouldn't be interrupted. Hence it must be called with interrupts disabled.
143 * 127 *
144 * Must be called with interrupts disabled. 128 * Must be called with interrupts disabled.
145 * 129 *
146 * Return conditions are same as __raw_notifie 130 * Return conditions are same as __raw_notifier_call_chain.
147 */ 131 */
148 int cpu_cluster_pm_enter(void) 132 int cpu_cluster_pm_enter(void)
149 { 133 {
150 return cpu_pm_notify_robust(CPU_CLUSTE !! 134 int nr_calls = 0;
>> 135 int ret = 0;
>> 136
>> 137 ret = cpu_pm_notify(CPU_CLUSTER_PM_ENTER, -1, &nr_calls);
>> 138 if (ret)
>> 139 /*
>> 140 * Inform listeners (nr_calls - 1) about failure of CPU cluster
>> 141 * PM entry who are notified earlier to prepare for it.
>> 142 */
>> 143 cpu_pm_notify(CPU_CLUSTER_PM_ENTER_FAILED, nr_calls - 1, NULL);
>> 144
>> 145 return ret;
151 } 146 }
152 EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter); 147 EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter);
153 148
154 /** 149 /**
155 * cpu_cluster_pm_exit - CPU cluster low power 150 * cpu_cluster_pm_exit - CPU cluster low power exit notifier
156 * 151 *
157 * Notifies listeners that all cpus in a power 152 * Notifies listeners that all cpus in a power domain are exiting form a
158 * low power state that may have caused some b 153 * low power state that may have caused some blocks in the same power domain
159 * to reset. 154 * to reset.
160 * 155 *
161 * Must be called after cpu_cluster_pm_enter h 156 * Must be called after cpu_cluster_pm_enter has been called for the power
162 * domain, and before cpu_pm_exit has been cal 157 * domain, and before cpu_pm_exit has been called on any cpu in the power
163 * domain. Notified drivers can include VFP co 158 * domain. Notified drivers can include VFP co-processor, interrupt controller
164 * and its PM extensions, local CPU timers con 159 * and its PM extensions, local CPU timers context save/restore which
165 * shouldn't be interrupted. Hence it must be 160 * shouldn't be interrupted. Hence it must be called with interrupts disabled.
166 * 161 *
167 * Return conditions are same as __raw_notifie 162 * Return conditions are same as __raw_notifier_call_chain.
168 */ 163 */
169 int cpu_cluster_pm_exit(void) 164 int cpu_cluster_pm_exit(void)
170 { 165 {
171 return cpu_pm_notify(CPU_CLUSTER_PM_EX !! 166 return cpu_pm_notify(CPU_CLUSTER_PM_EXIT, -1, NULL);
172 } 167 }
173 EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit); 168 EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit);
174 169
175 #ifdef CONFIG_PM 170 #ifdef CONFIG_PM
176 static int cpu_pm_suspend(void) 171 static int cpu_pm_suspend(void)
177 { 172 {
178 int ret; 173 int ret;
179 174
180 ret = cpu_pm_enter(); 175 ret = cpu_pm_enter();
181 if (ret) 176 if (ret)
182 return ret; 177 return ret;
183 178
184 ret = cpu_cluster_pm_enter(); 179 ret = cpu_cluster_pm_enter();
185 return ret; 180 return ret;
186 } 181 }
187 182
188 static void cpu_pm_resume(void) 183 static void cpu_pm_resume(void)
189 { 184 {
190 cpu_cluster_pm_exit(); 185 cpu_cluster_pm_exit();
191 cpu_pm_exit(); 186 cpu_pm_exit();
192 } 187 }
193 188
194 static struct syscore_ops cpu_pm_syscore_ops = 189 static struct syscore_ops cpu_pm_syscore_ops = {
195 .suspend = cpu_pm_suspend, 190 .suspend = cpu_pm_suspend,
196 .resume = cpu_pm_resume, 191 .resume = cpu_pm_resume,
197 }; 192 };
198 193
199 static int cpu_pm_init(void) 194 static int cpu_pm_init(void)
200 { 195 {
201 register_syscore_ops(&cpu_pm_syscore_o 196 register_syscore_ops(&cpu_pm_syscore_ops);
202 return 0; 197 return 0;
203 } 198 }
204 core_initcall(cpu_pm_init); 199 core_initcall(cpu_pm_init);
205 #endif 200 #endif
206 201
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