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* */#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>static DEFINE_RWLOCK(cpu_pm_notifier_lock);static RAW_NOTIFIER_HEAD(cpu_pm_notifier_chain);static ATOMIC_NOTIFIER_HEAD(cpu_pm_notifier_chain);static int cpu_pm_notify(enum cpu_pm_event event, int nr_to_call, int *nr_calls){ int ret; ret = __raw_notifier_call_chain(&cpu_pm_notifier_chain, event, NULL, /* * __atomic_notifier_call_chain has a RCU read critical section, which * could be disfunctional in cpu idle. Copy RCU_NONIDLE code to let * RCU know this. */ rcu_irq_enter_irqson(); ret = __atomic_notifier_call_chain(&cpu_pm_notifier_chain, event, NULL, nr_to_call, nr_calls); rcu_irq_exit_irqson(); 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 may sleep, and has the same return conditions as * raw_notifier_chain_register. */int cpu_pm_register_notifier(struct notifier_block *nb){ unsigned long flags; int ret; write_lock_irqsave(&cpu_pm_notifier_lock, flags); ret = raw_notifier_chain_register(&cpu_pm_notifier_chain, nb); write_unlock_irqrestore(&cpu_pm_notifier_lock, flags); return ret; return atomic_notifier_chain_register(&cpu_pm_notifier_chain, nb);}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 may sleep, and has the same return conditions as * raw_notifier_chain_unregister. */int cpu_pm_unregister_notifier(struct notifier_block *nb){ unsigned long flags; int ret; write_lock_irqsave(&cpu_pm_notifier_lock, flags); ret = raw_notifier_chain_unregister(&cpu_pm_notifier_chain, nb); write_unlock_irqrestore(&cpu_pm_notifier_lock, flags); return ret; return atomic_notifier_chain_unregister(&cpu_pm_notifier_chain, nb);}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 * 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){ int nr_calls; int ret = 0; read_lock(&cpu_pm_notifier_lock); ret = cpu_pm_notify(CPU_PM_ENTER, -1, &nr_calls); if (ret) /* * Inform listeners (nr_calls - 1) about failure of CPU PM * PM entry who are notified earlier to prepare for it. */ cpu_pm_notify(CPU_PM_ENTER_FAILED, nr_calls - 1, NULL); read_unlock(&cpu_pm_notifier_lock); return ret;}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){ int ret; read_lock(&cpu_pm_notifier_lock); ret = cpu_pm_notify(CPU_PM_EXIT, -1, NULL); read_unlock(&cpu_pm_notifier_lock); return ret; return cpu_pm_notify(CPU_PM_EXIT, -1, NULL);}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 * * Must be called with interrupts disabled. * * Return conditions are same as __raw_notifier_call_chain. */int cpu_cluster_pm_enter(void){ int nr_calls; int ret = 0; read_lock(&cpu_pm_notifier_lock); ret = cpu_pm_notify(CPU_CLUSTER_PM_ENTER, -1, &nr_calls); if (ret) /* * Inform listeners (nr_calls - 1) about failure of CPU cluster * PM entry who are notified earlier to prepare for it. */ cpu_pm_notify(CPU_CLUSTER_PM_ENTER_FAILED, nr_calls - 1, NULL); read_unlock(&cpu_pm_notifier_lock); return ret;}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 * 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){ int ret; read_lock(&cpu_pm_notifier_lock); ret = cpu_pm_notify(CPU_CLUSTER_PM_EXIT, -1, NULL); read_unlock(&cpu_pm_notifier_lock); return ret; return cpu_pm_notify(CPU_CLUSTER_PM_EXIT, -1, NULL);}EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit);#ifdef CONFIG_PMstatic int cpu_pm_suspend(void){ int ret; ret = cpu_pm_enter(); if (ret)