210 lines
6 KiB
C
210 lines
6 KiB
C
/*
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* Copyright (C) 2011 Google, Inc.
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*
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* Author:
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* Colin Cross <ccross@android.com>
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/cpu_pm.h>
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#include <linux/module.h>
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#include <linux/notifier.h>
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#include <linux/spinlock.h>
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#include <linux/syscore_ops.h>
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static ATOMIC_NOTIFIER_HEAD(cpu_pm_notifier_chain);
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static int cpu_pm_notify(enum cpu_pm_event event, int nr_to_call, int *nr_calls)
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{
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int ret;
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/*
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* __atomic_notifier_call_chain has a RCU read critical section, which
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* could be disfunctional in cpu idle. Copy RCU_NONIDLE code to let
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* RCU know this.
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*/
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rcu_irq_enter_irqson();
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ret = __atomic_notifier_call_chain(&cpu_pm_notifier_chain, event, NULL,
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nr_to_call, nr_calls);
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rcu_irq_exit_irqson();
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return notifier_to_errno(ret);
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}
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/**
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* cpu_pm_register_notifier - register a driver with cpu_pm
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* @nb: notifier block to register
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*
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* Add a driver to a list of drivers that are notified about
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* CPU and CPU cluster low power entry and exit.
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*
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* This function may sleep, and has the same return conditions as
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* raw_notifier_chain_register.
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*/
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int cpu_pm_register_notifier(struct notifier_block *nb)
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{
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return atomic_notifier_chain_register(&cpu_pm_notifier_chain, nb);
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}
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EXPORT_SYMBOL_GPL(cpu_pm_register_notifier);
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/**
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* cpu_pm_unregister_notifier - unregister a driver with cpu_pm
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* @nb: notifier block to be unregistered
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*
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* Remove a driver from the CPU PM notifier list.
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*
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* This function may sleep, and has the same return conditions as
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* raw_notifier_chain_unregister.
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*/
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int cpu_pm_unregister_notifier(struct notifier_block *nb)
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{
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return atomic_notifier_chain_unregister(&cpu_pm_notifier_chain, nb);
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}
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EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier);
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/**
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* cpu_pm_enter - CPU low power entry notifier
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*
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* Notifies listeners that a single CPU is entering a low power state that may
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* cause some blocks in the same power domain as the cpu to reset.
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*
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* Must be called on the affected CPU with interrupts disabled. Platform is
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* responsible for ensuring that cpu_pm_enter is not called twice on the same
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* CPU before cpu_pm_exit is called. Notified drivers can include VFP
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* co-processor, interrupt controller and its PM extensions, local CPU
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* timers context save/restore which shouldn't be interrupted. Hence it
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* must be called with interrupts disabled.
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*
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* Return conditions are same as __raw_notifier_call_chain.
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*/
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int cpu_pm_enter(void)
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{
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int nr_calls = 0;
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int ret = 0;
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ret = cpu_pm_notify(CPU_PM_ENTER, -1, &nr_calls);
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if (ret)
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/*
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* Inform listeners (nr_calls - 1) about failure of CPU PM
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* PM entry who are notified earlier to prepare for it.
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*/
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cpu_pm_notify(CPU_PM_ENTER_FAILED, nr_calls - 1, NULL);
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return ret;
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}
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EXPORT_SYMBOL_GPL(cpu_pm_enter);
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/**
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* cpu_pm_exit - CPU low power exit notifier
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*
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* Notifies listeners that a single CPU is exiting a low power state that may
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* have caused some blocks in the same power domain as the cpu to reset.
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*
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* Notified drivers can include VFP co-processor, interrupt controller
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* and its PM extensions, local CPU timers context save/restore which
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* shouldn't be interrupted. Hence it must be called with interrupts disabled.
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*
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* Return conditions are same as __raw_notifier_call_chain.
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*/
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int cpu_pm_exit(void)
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{
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return cpu_pm_notify(CPU_PM_EXIT, -1, NULL);
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}
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EXPORT_SYMBOL_GPL(cpu_pm_exit);
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/**
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* cpu_cluster_pm_enter - CPU cluster low power entry notifier
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*
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* Notifies listeners that all cpus in a power domain are entering a low power
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* state that may cause some blocks in the same power domain to reset.
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*
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* Must be called after cpu_pm_enter has been called on all cpus in the power
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* domain, and before cpu_pm_exit has been called on any cpu in the power
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* domain. Notified drivers can include VFP co-processor, interrupt controller
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* and its PM extensions, local CPU timers context save/restore which
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* shouldn't be interrupted. Hence it must be called with interrupts disabled.
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*
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* Must be called with interrupts disabled.
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*
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* Return conditions are same as __raw_notifier_call_chain.
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*/
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int cpu_cluster_pm_enter(void)
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{
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int nr_calls = 0;
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int ret = 0;
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ret = cpu_pm_notify(CPU_CLUSTER_PM_ENTER, -1, &nr_calls);
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if (ret)
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/*
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* Inform listeners (nr_calls - 1) about failure of CPU cluster
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* PM entry who are notified earlier to prepare for it.
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*/
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cpu_pm_notify(CPU_CLUSTER_PM_ENTER_FAILED, nr_calls - 1, NULL);
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return ret;
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}
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EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter);
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/**
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* cpu_cluster_pm_exit - CPU cluster low power exit notifier
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*
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* Notifies listeners that all cpus in a power domain are exiting form a
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* low power state that may have caused some blocks in the same power domain
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* to reset.
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*
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* Must be called after cpu_cluster_pm_enter has been called for the power
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* domain, and before cpu_pm_exit has been called on any cpu in the power
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* domain. Notified drivers can include VFP co-processor, interrupt controller
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* and its PM extensions, local CPU timers context save/restore which
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* shouldn't be interrupted. Hence it must be called with interrupts disabled.
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*
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* Return conditions are same as __raw_notifier_call_chain.
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*/
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int cpu_cluster_pm_exit(void)
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{
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return cpu_pm_notify(CPU_CLUSTER_PM_EXIT, -1, NULL);
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}
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EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit);
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#ifdef CONFIG_PM
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static int cpu_pm_suspend(void)
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{
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int ret;
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ret = cpu_pm_enter();
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if (ret)
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return ret;
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ret = cpu_cluster_pm_enter();
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return ret;
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}
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static void cpu_pm_resume(void)
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{
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cpu_cluster_pm_exit();
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cpu_pm_exit();
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}
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static struct syscore_ops cpu_pm_syscore_ops = {
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.suspend = cpu_pm_suspend,
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.resume = cpu_pm_resume,
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};
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static int cpu_pm_init(void)
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{
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register_syscore_ops(&cpu_pm_syscore_ops);
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return 0;
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}
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core_initcall(cpu_pm_init);
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#endif
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