/* * Copyright (C) 2011 Google, Inc. * * Author: *	Colin Cross <ccross@android.com> * * This software is licensed under the terms of the GNU General Public * License version 2, as published by the Free Software Foundation, and * may be copied, distributed, and modified under those terms. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * GNU General Public License for more details. * */ #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 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,		nr_to_call, nr_calls); 	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;}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;}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){	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;}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){	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 * to reset. * * Must be called after cpu_pm_exit 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. * * 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;}EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit); #ifdef CONFIG_PMstatic int cpu_pm_suspend(void){	int ret; 	ret = cpu_pm_enter();	if (ret)		return ret; 	ret = cpu_cluster_pm_enter();	return ret;} static void cpu_pm_resume(void){	cpu_cluster_pm_exit();	cpu_pm_exit();} static struct syscore_ops cpu_pm_syscore_ops = {	.suspend = cpu_pm_suspend,	.resume = cpu_pm_resume,}; static int cpu_pm_init(void){	register_syscore_ops(&cpu_pm_syscore_ops);	return 0;}core_initcall(cpu_pm_init);#endif