1 // SPDX-License-Identifier: GPL-2.0-only <<
2 /* 1 /*
3 * Copyright (C) 2011 Google, Inc. 2 * Copyright (C) 2011 Google, Inc.
4 * 3 *
5 * Author: 4 * Author:
6 * Colin Cross <ccross@android.com> 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 *
7 */ 16 */
8 17
9 #include <linux/kernel.h> 18 #include <linux/kernel.h>
10 #include <linux/cpu_pm.h> 19 #include <linux/cpu_pm.h>
11 #include <linux/module.h> 20 #include <linux/module.h>
12 #include <linux/notifier.h> 21 #include <linux/notifier.h>
13 #include <linux/spinlock.h> 22 #include <linux/spinlock.h>
14 #include <linux/syscore_ops.h> 23 #include <linux/syscore_ops.h>
15 24
16 /* !! 25 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 26
29 static int cpu_pm_notify(enum cpu_pm_event eve !! 27 static int cpu_pm_notify(enum cpu_pm_event event, int nr_to_call, int *nr_calls)
30 { 28 {
31 int ret; 29 int ret;
32 30
33 rcu_read_lock(); !! 31 /*
34 ret = raw_notifier_call_chain(&cpu_pm_ !! 32 * __atomic_notifier_call_chain has a RCU read critical section, which
35 rcu_read_unlock(); !! 33 * could be disfunctional in cpu idle. Copy RCU_NONIDLE code to let
36 !! 34 * RCU know this.
37 return notifier_to_errno(ret); !! 35 */
38 } !! 36 rcu_irq_enter_irqson();
39 !! 37 ret = __atomic_notifier_call_chain(&cpu_pm_notifier_chain, event, NULL,
40 static int cpu_pm_notify_robust(enum cpu_pm_ev !! 38 nr_to_call, nr_calls);
41 { !! 39 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 40
49 return notifier_to_errno(ret); 41 return notifier_to_errno(ret);
50 } 42 }
51 43
52 /** 44 /**
53 * cpu_pm_register_notifier - register a drive 45 * cpu_pm_register_notifier - register a driver with cpu_pm
54 * @nb: notifier block to register 46 * @nb: notifier block to register
55 * 47 *
56 * Add a driver to a list of drivers that are 48 * Add a driver to a list of drivers that are notified about
57 * CPU and CPU cluster low power entry and exi 49 * CPU and CPU cluster low power entry and exit.
58 * 50 *
59 * This function has the same return condition !! 51 * This function may sleep, and has the same return conditions as
>> 52 * raw_notifier_chain_register.
60 */ 53 */
61 int cpu_pm_register_notifier(struct notifier_b 54 int cpu_pm_register_notifier(struct notifier_block *nb)
62 { 55 {
63 unsigned long flags; !! 56 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 } 57 }
71 EXPORT_SYMBOL_GPL(cpu_pm_register_notifier); 58 EXPORT_SYMBOL_GPL(cpu_pm_register_notifier);
72 59
73 /** 60 /**
74 * cpu_pm_unregister_notifier - unregister a d 61 * cpu_pm_unregister_notifier - unregister a driver with cpu_pm
75 * @nb: notifier block to be unregistered 62 * @nb: notifier block to be unregistered
76 * 63 *
77 * Remove a driver from the CPU PM notifier li 64 * Remove a driver from the CPU PM notifier list.
78 * 65 *
79 * This function has the same return condition !! 66 * This function may sleep, and has the same return conditions as
>> 67 * raw_notifier_chain_unregister.
80 */ 68 */
81 int cpu_pm_unregister_notifier(struct notifier 69 int cpu_pm_unregister_notifier(struct notifier_block *nb)
82 { 70 {
83 unsigned long flags; !! 71 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 } 72 }
91 EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier); 73 EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier);
92 74
93 /** 75 /**
94 * cpu_pm_enter - CPU low power entry notifier 76 * cpu_pm_enter - CPU low power entry notifier
95 * 77 *
96 * Notifies listeners that a single CPU is ent 78 * Notifies listeners that a single CPU is entering a low power state that may
97 * cause some blocks in the same power domain 79 * cause some blocks in the same power domain as the cpu to reset.
98 * 80 *
99 * Must be called on the affected CPU with int 81 * Must be called on the affected CPU with interrupts disabled. Platform is
100 * responsible for ensuring that cpu_pm_enter 82 * responsible for ensuring that cpu_pm_enter is not called twice on the same
101 * CPU before cpu_pm_exit is called. Notified 83 * CPU before cpu_pm_exit is called. Notified drivers can include VFP
102 * co-processor, interrupt controller and its 84 * co-processor, interrupt controller and its PM extensions, local CPU
103 * timers context save/restore which shouldn't 85 * timers context save/restore which shouldn't be interrupted. Hence it
104 * must be called with interrupts disabled. 86 * must be called with interrupts disabled.
105 * 87 *
106 * Return conditions are same as __raw_notifie 88 * Return conditions are same as __raw_notifier_call_chain.
107 */ 89 */
108 int cpu_pm_enter(void) 90 int cpu_pm_enter(void)
109 { 91 {
110 return cpu_pm_notify_robust(CPU_PM_ENT !! 92 int nr_calls;
>> 93 int ret = 0;
>> 94
>> 95 ret = cpu_pm_notify(CPU_PM_ENTER, -1, &nr_calls);
>> 96 if (ret)
>> 97 /*
>> 98 * Inform listeners (nr_calls - 1) about failure of CPU PM
>> 99 * PM entry who are notified earlier to prepare for it.
>> 100 */
>> 101 cpu_pm_notify(CPU_PM_ENTER_FAILED, nr_calls - 1, NULL);
>> 102
>> 103 return ret;
111 } 104 }
112 EXPORT_SYMBOL_GPL(cpu_pm_enter); 105 EXPORT_SYMBOL_GPL(cpu_pm_enter);
113 106
114 /** 107 /**
115 * cpu_pm_exit - CPU low power exit notifier 108 * cpu_pm_exit - CPU low power exit notifier
116 * 109 *
117 * Notifies listeners that a single CPU is exi 110 * Notifies listeners that a single CPU is exiting a low power state that may
118 * have caused some blocks in the same power d 111 * have caused some blocks in the same power domain as the cpu to reset.
119 * 112 *
120 * Notified drivers can include VFP co-process 113 * Notified drivers can include VFP co-processor, interrupt controller
121 * and its PM extensions, local CPU timers con 114 * and its PM extensions, local CPU timers context save/restore which
122 * shouldn't be interrupted. Hence it must be 115 * shouldn't be interrupted. Hence it must be called with interrupts disabled.
123 * 116 *
124 * Return conditions are same as __raw_notifie 117 * Return conditions are same as __raw_notifier_call_chain.
125 */ 118 */
126 int cpu_pm_exit(void) 119 int cpu_pm_exit(void)
127 { 120 {
128 return cpu_pm_notify(CPU_PM_EXIT); !! 121 return cpu_pm_notify(CPU_PM_EXIT, -1, NULL);
129 } 122 }
130 EXPORT_SYMBOL_GPL(cpu_pm_exit); 123 EXPORT_SYMBOL_GPL(cpu_pm_exit);
131 124
132 /** 125 /**
133 * cpu_cluster_pm_enter - CPU cluster low powe 126 * cpu_cluster_pm_enter - CPU cluster low power entry notifier
134 * 127 *
135 * Notifies listeners that all cpus in a power 128 * Notifies listeners that all cpus in a power domain are entering a low power
136 * state that may cause some blocks in the sam 129 * state that may cause some blocks in the same power domain to reset.
137 * 130 *
138 * Must be called after cpu_pm_enter has been 131 * 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 132 * domain, and before cpu_pm_exit has been called on any cpu in the power
140 * domain. Notified drivers can include VFP co 133 * domain. Notified drivers can include VFP co-processor, interrupt controller
141 * and its PM extensions, local CPU timers con 134 * and its PM extensions, local CPU timers context save/restore which
142 * shouldn't be interrupted. Hence it must be 135 * shouldn't be interrupted. Hence it must be called with interrupts disabled.
143 * 136 *
144 * Must be called with interrupts disabled. 137 * Must be called with interrupts disabled.
145 * 138 *
146 * Return conditions are same as __raw_notifie 139 * Return conditions are same as __raw_notifier_call_chain.
147 */ 140 */
148 int cpu_cluster_pm_enter(void) 141 int cpu_cluster_pm_enter(void)
149 { 142 {
150 return cpu_pm_notify_robust(CPU_CLUSTE !! 143 int nr_calls;
>> 144 int ret = 0;
>> 145
>> 146 ret = cpu_pm_notify(CPU_CLUSTER_PM_ENTER, -1, &nr_calls);
>> 147 if (ret)
>> 148 /*
>> 149 * Inform listeners (nr_calls - 1) about failure of CPU cluster
>> 150 * PM entry who are notified earlier to prepare for it.
>> 151 */
>> 152 cpu_pm_notify(CPU_CLUSTER_PM_ENTER_FAILED, nr_calls - 1, NULL);
>> 153
>> 154 return ret;
151 } 155 }
152 EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter); 156 EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter);
153 157
154 /** 158 /**
155 * cpu_cluster_pm_exit - CPU cluster low power 159 * cpu_cluster_pm_exit - CPU cluster low power exit notifier
156 * 160 *
157 * Notifies listeners that all cpus in a power 161 * Notifies listeners that all cpus in a power domain are exiting form a
158 * low power state that may have caused some b 162 * low power state that may have caused some blocks in the same power domain
159 * to reset. 163 * to reset.
160 * 164 *
161 * Must be called after cpu_cluster_pm_enter h 165 * Must be called after cpu_cluster_pm_enter has been called for the power
162 * domain, and before cpu_pm_exit has been cal 166 * domain, and before cpu_pm_exit has been called on any cpu in the power
163 * domain. Notified drivers can include VFP co 167 * domain. Notified drivers can include VFP co-processor, interrupt controller
164 * and its PM extensions, local CPU timers con 168 * and its PM extensions, local CPU timers context save/restore which
165 * shouldn't be interrupted. Hence it must be 169 * shouldn't be interrupted. Hence it must be called with interrupts disabled.
166 * 170 *
167 * Return conditions are same as __raw_notifie 171 * Return conditions are same as __raw_notifier_call_chain.
168 */ 172 */
169 int cpu_cluster_pm_exit(void) 173 int cpu_cluster_pm_exit(void)
170 { 174 {
171 return cpu_pm_notify(CPU_CLUSTER_PM_EX !! 175 return cpu_pm_notify(CPU_CLUSTER_PM_EXIT, -1, NULL);
172 } 176 }
173 EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit); 177 EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit);
174 178
175 #ifdef CONFIG_PM 179 #ifdef CONFIG_PM
176 static int cpu_pm_suspend(void) 180 static int cpu_pm_suspend(void)
177 { 181 {
178 int ret; 182 int ret;
179 183
180 ret = cpu_pm_enter(); 184 ret = cpu_pm_enter();
181 if (ret) 185 if (ret)
182 return ret; 186 return ret;
183 187
184 ret = cpu_cluster_pm_enter(); 188 ret = cpu_cluster_pm_enter();
185 return ret; 189 return ret;
186 } 190 }
187 191
188 static void cpu_pm_resume(void) 192 static void cpu_pm_resume(void)
189 { 193 {
190 cpu_cluster_pm_exit(); 194 cpu_cluster_pm_exit();
191 cpu_pm_exit(); 195 cpu_pm_exit();
192 } 196 }
193 197
194 static struct syscore_ops cpu_pm_syscore_ops = 198 static struct syscore_ops cpu_pm_syscore_ops = {
195 .suspend = cpu_pm_suspend, 199 .suspend = cpu_pm_suspend,
196 .resume = cpu_pm_resume, 200 .resume = cpu_pm_resume,
197 }; 201 };
198 202
199 static int cpu_pm_init(void) 203 static int cpu_pm_init(void)
200 { 204 {
201 register_syscore_ops(&cpu_pm_syscore_o 205 register_syscore_ops(&cpu_pm_syscore_ops);
202 return 0; 206 return 0;
203 } 207 }
204 core_initcall(cpu_pm_init); 208 core_initcall(cpu_pm_init);
205 #endif 209 #endif
206 210
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