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)
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
>> 25 * RCU know this.
>> 26 */
>> 27 rcu_irq_enter_irqson();
>> 28 ret = atomic_notifier_call_chain(&cpu_pm_notifier_chain, event, NULL);
>> 29 rcu_irq_exit_irqson();
36 30
37 return notifier_to_errno(ret); 31 return notifier_to_errno(ret);
38 } 32 }
39 33
40 static int cpu_pm_notify_robust(enum cpu_pm_ev 34 static int cpu_pm_notify_robust(enum cpu_pm_event event_up, enum cpu_pm_event event_down)
41 { 35 {
42 unsigned long flags; <<
43 int ret; 36 int ret;
44 37
45 raw_spin_lock_irqsave(&cpu_pm_notifier !! 38 rcu_irq_enter_irqson();
46 ret = raw_notifier_call_chain_robust(& !! 39 ret = atomic_notifier_call_chain_robust(&cpu_pm_notifier_chain, event_up, event_down, NULL);
47 raw_spin_unlock_irqrestore(&cpu_pm_not !! 40 rcu_irq_exit_irqson();
48 41
49 return notifier_to_errno(ret); 42 return notifier_to_errno(ret);
50 } 43 }
51 44
52 /** 45 /**
53 * cpu_pm_register_notifier - register a drive 46 * cpu_pm_register_notifier - register a driver with cpu_pm
54 * @nb: notifier block to register 47 * @nb: notifier block to register
55 * 48 *
56 * Add a driver to a list of drivers that are 49 * Add a driver to a list of drivers that are notified about
57 * CPU and CPU cluster low power entry and exi 50 * CPU and CPU cluster low power entry and exit.
58 * 51 *
59 * This function has the same return condition !! 52 * This function may sleep, and has the same return conditions as
>> 53 * raw_notifier_chain_register.
60 */ 54 */
61 int cpu_pm_register_notifier(struct notifier_b 55 int cpu_pm_register_notifier(struct notifier_block *nb)
62 { 56 {
63 unsigned long flags; !! 57 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 } 58 }
71 EXPORT_SYMBOL_GPL(cpu_pm_register_notifier); 59 EXPORT_SYMBOL_GPL(cpu_pm_register_notifier);
72 60
73 /** 61 /**
74 * cpu_pm_unregister_notifier - unregister a d 62 * cpu_pm_unregister_notifier - unregister a driver with cpu_pm
75 * @nb: notifier block to be unregistered 63 * @nb: notifier block to be unregistered
76 * 64 *
77 * Remove a driver from the CPU PM notifier li 65 * Remove a driver from the CPU PM notifier list.
78 * 66 *
79 * This function has the same return condition !! 67 * This function may sleep, and has the same return conditions as
>> 68 * raw_notifier_chain_unregister.
80 */ 69 */
81 int cpu_pm_unregister_notifier(struct notifier 70 int cpu_pm_unregister_notifier(struct notifier_block *nb)
82 { 71 {
83 unsigned long flags; !! 72 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 } 73 }
91 EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier); 74 EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier);
92 75
93 /** 76 /**
94 * cpu_pm_enter - CPU low power entry notifier 77 * cpu_pm_enter - CPU low power entry notifier
95 * 78 *
96 * Notifies listeners that a single CPU is ent 79 * Notifies listeners that a single CPU is entering a low power state that may
97 * cause some blocks in the same power domain 80 * cause some blocks in the same power domain as the cpu to reset.
98 * 81 *
99 * Must be called on the affected CPU with int 82 * Must be called on the affected CPU with interrupts disabled. Platform is
100 * responsible for ensuring that cpu_pm_enter 83 * responsible for ensuring that cpu_pm_enter is not called twice on the same
101 * CPU before cpu_pm_exit is called. Notified 84 * CPU before cpu_pm_exit is called. Notified drivers can include VFP
102 * co-processor, interrupt controller and its 85 * co-processor, interrupt controller and its PM extensions, local CPU
103 * timers context save/restore which shouldn't 86 * timers context save/restore which shouldn't be interrupted. Hence it
104 * must be called with interrupts disabled. 87 * must be called with interrupts disabled.
105 * 88 *
106 * Return conditions are same as __raw_notifie 89 * Return conditions are same as __raw_notifier_call_chain.
107 */ 90 */
108 int cpu_pm_enter(void) 91 int cpu_pm_enter(void)
109 { 92 {
110 return cpu_pm_notify_robust(CPU_PM_ENT 93 return cpu_pm_notify_robust(CPU_PM_ENTER, CPU_PM_ENTER_FAILED);
111 } 94 }
112 EXPORT_SYMBOL_GPL(cpu_pm_enter); 95 EXPORT_SYMBOL_GPL(cpu_pm_enter);
113 96
114 /** 97 /**
115 * cpu_pm_exit - CPU low power exit notifier 98 * cpu_pm_exit - CPU low power exit notifier
116 * 99 *
117 * Notifies listeners that a single CPU is exi 100 * Notifies listeners that a single CPU is exiting a low power state that may
118 * have caused some blocks in the same power d 101 * have caused some blocks in the same power domain as the cpu to reset.
119 * 102 *
120 * Notified drivers can include VFP co-process 103 * Notified drivers can include VFP co-processor, interrupt controller
121 * and its PM extensions, local CPU timers con 104 * and its PM extensions, local CPU timers context save/restore which
122 * shouldn't be interrupted. Hence it must be 105 * shouldn't be interrupted. Hence it must be called with interrupts disabled.
123 * 106 *
124 * Return conditions are same as __raw_notifie 107 * Return conditions are same as __raw_notifier_call_chain.
125 */ 108 */
126 int cpu_pm_exit(void) 109 int cpu_pm_exit(void)
127 { 110 {
128 return cpu_pm_notify(CPU_PM_EXIT); 111 return cpu_pm_notify(CPU_PM_EXIT);
129 } 112 }
130 EXPORT_SYMBOL_GPL(cpu_pm_exit); 113 EXPORT_SYMBOL_GPL(cpu_pm_exit);
131 114
132 /** 115 /**
133 * cpu_cluster_pm_enter - CPU cluster low powe 116 * cpu_cluster_pm_enter - CPU cluster low power entry notifier
134 * 117 *
135 * Notifies listeners that all cpus in a power 118 * Notifies listeners that all cpus in a power domain are entering a low power
136 * state that may cause some blocks in the sam 119 * state that may cause some blocks in the same power domain to reset.
137 * 120 *
138 * Must be called after cpu_pm_enter has been 121 * 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 122 * domain, and before cpu_pm_exit has been called on any cpu in the power
140 * domain. Notified drivers can include VFP co 123 * domain. Notified drivers can include VFP co-processor, interrupt controller
141 * and its PM extensions, local CPU timers con 124 * and its PM extensions, local CPU timers context save/restore which
142 * shouldn't be interrupted. Hence it must be 125 * shouldn't be interrupted. Hence it must be called with interrupts disabled.
143 * 126 *
144 * Must be called with interrupts disabled. 127 * Must be called with interrupts disabled.
145 * 128 *
146 * Return conditions are same as __raw_notifie 129 * Return conditions are same as __raw_notifier_call_chain.
147 */ 130 */
148 int cpu_cluster_pm_enter(void) 131 int cpu_cluster_pm_enter(void)
149 { 132 {
150 return cpu_pm_notify_robust(CPU_CLUSTE 133 return cpu_pm_notify_robust(CPU_CLUSTER_PM_ENTER, CPU_CLUSTER_PM_ENTER_FAILED);
151 } 134 }
152 EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter); 135 EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter);
153 136
154 /** 137 /**
155 * cpu_cluster_pm_exit - CPU cluster low power 138 * cpu_cluster_pm_exit - CPU cluster low power exit notifier
156 * 139 *
157 * Notifies listeners that all cpus in a power 140 * Notifies listeners that all cpus in a power domain are exiting form a
158 * low power state that may have caused some b 141 * low power state that may have caused some blocks in the same power domain
159 * to reset. 142 * to reset.
160 * 143 *
161 * Must be called after cpu_cluster_pm_enter h 144 * Must be called after cpu_cluster_pm_enter has been called for the power
162 * domain, and before cpu_pm_exit has been cal 145 * domain, and before cpu_pm_exit has been called on any cpu in the power
163 * domain. Notified drivers can include VFP co 146 * domain. Notified drivers can include VFP co-processor, interrupt controller
164 * and its PM extensions, local CPU timers con 147 * and its PM extensions, local CPU timers context save/restore which
165 * shouldn't be interrupted. Hence it must be 148 * shouldn't be interrupted. Hence it must be called with interrupts disabled.
166 * 149 *
167 * Return conditions are same as __raw_notifie 150 * Return conditions are same as __raw_notifier_call_chain.
168 */ 151 */
169 int cpu_cluster_pm_exit(void) 152 int cpu_cluster_pm_exit(void)
170 { 153 {
171 return cpu_pm_notify(CPU_CLUSTER_PM_EX 154 return cpu_pm_notify(CPU_CLUSTER_PM_EXIT);
172 } 155 }
173 EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit); 156 EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit);
174 157
175 #ifdef CONFIG_PM 158 #ifdef CONFIG_PM
176 static int cpu_pm_suspend(void) 159 static int cpu_pm_suspend(void)
177 { 160 {
178 int ret; 161 int ret;
179 162
180 ret = cpu_pm_enter(); 163 ret = cpu_pm_enter();
181 if (ret) 164 if (ret)
182 return ret; 165 return ret;
183 166
184 ret = cpu_cluster_pm_enter(); 167 ret = cpu_cluster_pm_enter();
185 return ret; 168 return ret;
186 } 169 }
187 170
188 static void cpu_pm_resume(void) 171 static void cpu_pm_resume(void)
189 { 172 {
190 cpu_cluster_pm_exit(); 173 cpu_cluster_pm_exit();
191 cpu_pm_exit(); 174 cpu_pm_exit();
192 } 175 }
193 176
194 static struct syscore_ops cpu_pm_syscore_ops = 177 static struct syscore_ops cpu_pm_syscore_ops = {
195 .suspend = cpu_pm_suspend, 178 .suspend = cpu_pm_suspend,
196 .resume = cpu_pm_resume, 179 .resume = cpu_pm_resume,
197 }; 180 };
198 181
199 static int cpu_pm_init(void) 182 static int cpu_pm_init(void)
200 { 183 {
201 register_syscore_ops(&cpu_pm_syscore_o 184 register_syscore_ops(&cpu_pm_syscore_ops);
202 return 0; 185 return 0;
203 } 186 }
204 core_initcall(cpu_pm_init); 187 core_initcall(cpu_pm_init);
205 #endif 188 #endif
206 189
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