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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210// SPDX-License-Identifier: GPL-2.0-only/* * Copyright (C) 2011 Google, Inc. * * Author: * Colin Cross <ccross@android.com> */
#include <linux/kernel.h>#include <linux/cpu_pm.h>#include <linux/module.h>#include <linux/notifier.h>#include <linux/spinlock.h>#include <linux/syscore_ops.h>
/* * atomic_notifiers use a spinlock_t, which can block under PREEMPT_RT. * Notifications for cpu_pm will be issued by the idle task itself, which can * never block, IOW it requires using a raw_spinlock_t. */static struct { struct raw_notifier_head chain; raw_spinlock_t lock;} cpu_pm_notifier = { .chain = RAW_NOTIFIER_INIT(cpu_pm_notifier.chain), .lock = __RAW_SPIN_LOCK_UNLOCKED(cpu_pm_notifier.lock),};
static int cpu_pm_notify(enum cpu_pm_event event){ int ret;
rcu_read_lock(); ret = raw_notifier_call_chain(&cpu_pm_notifier.chain, event, NULL); rcu_read_unlock();
return notifier_to_errno(ret);}
static int cpu_pm_notify_robust(enum cpu_pm_event event_up, enum cpu_pm_event event_down){ unsigned long flags; int ret;
raw_spin_lock_irqsave(&cpu_pm_notifier.lock, flags); ret = raw_notifier_call_chain_robust(&cpu_pm_notifier.chain, event_up, event_down, NULL); raw_spin_unlock_irqrestore(&cpu_pm_notifier.lock, flags);
return notifier_to_errno(ret);}
/** * cpu_pm_register_notifier - register a driver with cpu_pm * @nb: notifier block to register * * Add a driver to a list of drivers that are notified about * CPU and CPU cluster low power entry and exit. * * This function has the same return conditions as raw_notifier_chain_register. */int cpu_pm_register_notifier(struct notifier_block *nb){ unsigned long flags; int ret;
raw_spin_lock_irqsave(&cpu_pm_notifier.lock, flags); ret = raw_notifier_chain_register(&cpu_pm_notifier.chain, nb); raw_spin_unlock_irqrestore(&cpu_pm_notifier.lock, flags); return ret;}EXPORT_SYMBOL_GPL(cpu_pm_register_notifier);
/** * cpu_pm_unregister_notifier - unregister a driver with cpu_pm * @nb: notifier block to be unregistered * * Remove a driver from the CPU PM notifier list. * * This function has the same return conditions as raw_notifier_chain_unregister. */int cpu_pm_unregister_notifier(struct notifier_block *nb){ unsigned long flags; int ret;
raw_spin_lock_irqsave(&cpu_pm_notifier.lock, flags); ret = raw_notifier_chain_unregister(&cpu_pm_notifier.chain, nb); raw_spin_unlock_irqrestore(&cpu_pm_notifier.lock, flags); return ret;}EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier);
/** * cpu_pm_enter - CPU low power entry notifier * * Notifies listeners that a single CPU is entering a low power state that may * cause some blocks in the same power domain as the cpu to reset. * * Must be called on the affected CPU with interrupts disabled. Platform is * responsible for ensuring that cpu_pm_enter is not called twice on the same * CPU before cpu_pm_exit is called. Notified drivers can include VFP * co-processor, interrupt controller and its PM extensions, local CPU * timers context save/restore which shouldn't be interrupted. Hence it * must be called with interrupts disabled. * * Return conditions are same as __raw_notifier_call_chain. */int cpu_pm_enter(void){ return cpu_pm_notify_robust(CPU_PM_ENTER, CPU_PM_ENTER_FAILED);}EXPORT_SYMBOL_GPL(cpu_pm_enter);
/** * cpu_pm_exit - CPU low power exit notifier * * Notifies listeners that a single CPU is exiting a low power state that may * have caused some blocks in the same power domain as the cpu to reset. * * Notified drivers can include VFP co-processor, interrupt controller * and its PM extensions, local CPU timers context save/restore which * shouldn't be interrupted. Hence it must be called with interrupts disabled. * * Return conditions are same as __raw_notifier_call_chain. */int cpu_pm_exit(void){ return cpu_pm_notify(CPU_PM_EXIT);}EXPORT_SYMBOL_GPL(cpu_pm_exit);
/** * cpu_cluster_pm_enter - CPU cluster low power entry notifier * * Notifies listeners that all cpus in a power domain are entering a low power * state that may cause some blocks in the same power domain to reset. * * Must be called after cpu_pm_enter has been called on all cpus in the power * domain, and before cpu_pm_exit has been called on any cpu in the power * domain. Notified drivers can include VFP co-processor, interrupt controller * and its PM extensions, local CPU timers context save/restore which * shouldn't be interrupted. Hence it must be called with interrupts disabled. * * Must be called with interrupts disabled. * * Return conditions are same as __raw_notifier_call_chain. */int cpu_cluster_pm_enter(void){ return cpu_pm_notify_robust(CPU_CLUSTER_PM_ENTER, CPU_CLUSTER_PM_ENTER_FAILED);}EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter);
/** * cpu_cluster_pm_exit - CPU cluster low power exit notifier * * Notifies listeners that all cpus in a power domain are exiting form a * low power state that may have caused some blocks in the same power domain * to reset. * * Must be called after cpu_cluster_pm_enter has been called for the power * domain, and before cpu_pm_exit has been called on any cpu in the power * domain. Notified drivers can include VFP co-processor, interrupt controller * and its PM extensions, local CPU timers context save/restore which * shouldn't be interrupted. Hence it must be called with interrupts disabled. * * Return conditions are same as __raw_notifier_call_chain. */int cpu_cluster_pm_exit(void){ return cpu_pm_notify(CPU_CLUSTER_PM_EXIT);}EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit);
#ifdef CONFIG_PMstatic int cpu_pm_suspend(void *data){ int ret;
ret = cpu_pm_enter(); if (ret) return ret;
ret = cpu_cluster_pm_enter(); return ret;}
static void cpu_pm_resume(void *data){ cpu_cluster_pm_exit(); cpu_pm_exit();}
static const struct syscore_ops cpu_pm_syscore_ops = { .suspend = cpu_pm_suspend, .resume = cpu_pm_resume,};
static struct syscore cpu_pm_syscore = { .ops = &cpu_pm_syscore_ops,};
static int cpu_pm_init(void){ register_syscore(&cpu_pm_syscore); return 0;}core_initcall(cpu_pm_init);#endif