cpu_pm: Add cpu power management notifiers (ab10023e) · Commits · 戴 / test

include/linux/cpu_pm.h

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		/*
		* 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.
		*
		*/

		#ifndef _LINUX_CPU_PM_H
		#define _LINUX_CPU_PM_H

		#include <linux/kernel.h>
		#include <linux/notifier.h>

		/*
		* When a CPU goes to a low power state that turns off power to the CPU's
		* power domain, the contents of some blocks (floating point coprocessors,
		* interrupt controllers, caches, timers) in the same power domain can
		* be lost. The cpm_pm notifiers provide a method for platform idle, suspend,
		* and hotplug implementations to notify the drivers for these blocks that
		* they may be reset.
		*
		* All cpu_pm notifications must be called with interrupts disabled.
		*
		* The notifications are split into two classes: CPU notifications and CPU
		* cluster notifications.
		*
		* CPU notifications apply to a single CPU and must be called on the affected
		* CPU. They are used to save per-cpu context for affected blocks.
		*
		* CPU cluster notifications apply to all CPUs in a single power domain. They
		* are used to save any global context for affected blocks, and must be called
		* after all the CPUs in the power domain have been notified of the low power
		* state.
		*/

		/*
		* Event codes passed as unsigned long val to notifier calls
		*/
		enum cpu_pm_event {
		/* A single cpu is entering a low power state */
		CPU_PM_ENTER,

		/* A single cpu failed to enter a low power state */
		CPU_PM_ENTER_FAILED,

		/* A single cpu is exiting a low power state */
		CPU_PM_EXIT,

		/* A cpu power domain is entering a low power state */
		CPU_CLUSTER_PM_ENTER,

		/* A cpu power domain failed to enter a low power state */
		CPU_CLUSTER_PM_ENTER_FAILED,

		/* A cpu power domain is exiting a low power state */
		CPU_CLUSTER_PM_EXIT,
		};

		#ifdef CONFIG_CPU_PM
		int cpu_pm_register_notifier(struct notifier_block *nb);
		int cpu_pm_unregister_notifier(struct notifier_block *nb);
		int cpu_pm_enter(void);
		int cpu_pm_exit(void);
		int cpu_cluster_pm_enter(void);
		int cpu_cluster_pm_exit(void);

		#else

		static inline int cpu_pm_register_notifier(struct notifier_block *nb)
		{
		return 0;
		}

		static inline int cpu_pm_unregister_notifier(struct notifier_block *nb)
		{
		return 0;
		}

		static inline int cpu_pm_enter(void)
		{
		return 0;
		}

		static inline int cpu_pm_exit(void)
		{
		return 0;
		}

		static inline int cpu_cluster_pm_enter(void)
		{
		return 0;
		}

		static inline int cpu_cluster_pm_exit(void)
		{
		return 0;
		}
		#endif
		#endif

kernel/Makefile

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		@@ -101,6 +101,7 @@ obj-$(CONFIG_RING_BUFFER) += trace/
		obj-$(CONFIG_TRACEPOINTS) += trace/
		obj-$(CONFIG_SMP) += sched_cpupri.o
		obj-$(CONFIG_IRQ_WORK) += irq_work.o
		obj-$(CONFIG_CPU_PM) += cpu_pm.o

		obj-$(CONFIG_PERF_EVENTS) += events/

kernel/cpu_pm.c

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		/*
		* 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>

		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);

		/**
		* cpm_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 it's 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);

		/**
		* cpm_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 it's 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);

		/**
		* cpm_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 it's 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);

		/**
		* cpm_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 it's 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);

kernel/power/Kconfig

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Original line number	Diff line number	Diff line
		@@ -235,3 +235,7 @@ config PM_GENERIC_DOMAINS
		config PM_GENERIC_DOMAINS_RUNTIME
		def_bool y
		depends on PM_RUNTIME && PM_GENERIC_DOMAINS

		config CPU_PM
		bool
		depends on SUSPEND \|\| CPU_IDLE

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