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![Colin Cross](/assets/img/avatar_default.png)
During some CPU power modes entered during idle, hotplug and suspend, peripherals located in the CPU power domain, such as the GIC, localtimers, and VFP, may be powered down. Add a notifier chain that allows drivers for those peripherals to be notified before and after they may be 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 CPU PM event APIs must be called with interrupts disabled. Signed-off-by: Colin Cross <ccross@android.com> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Kevin Hilman <khilman@ti.com> Tested-and-Acked-by: Shawn Guo <shawn.guo@linaro.org> Tested-by: Kevin Hilman <khilman@ti.com> Tested-by: Vishwanath BS <vishwanath.bs@ti.com>
109 lines
2.8 KiB
C
109 lines
2.8 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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#ifndef _LINUX_CPU_PM_H
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#define _LINUX_CPU_PM_H
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#include <linux/kernel.h>
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#include <linux/notifier.h>
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/*
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* When a CPU goes to a low power state that turns off power to the CPU's
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* power domain, the contents of some blocks (floating point coprocessors,
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* interrupt controllers, caches, timers) in the same power domain can
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* be lost. The cpm_pm notifiers provide a method for platform idle, suspend,
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* and hotplug implementations to notify the drivers for these blocks that
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* they may be reset.
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*
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* All cpu_pm notifications must be called with interrupts disabled.
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*
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* The notifications are split into two classes: CPU notifications and CPU
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* cluster notifications.
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*
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* CPU notifications apply to a single CPU and must be called on the affected
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* CPU. They are used to save per-cpu context for affected blocks.
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*
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* CPU cluster notifications apply to all CPUs in a single power domain. They
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* are used to save any global context for affected blocks, and must be called
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* after all the CPUs in the power domain have been notified of the low power
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* state.
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*/
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/*
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* Event codes passed as unsigned long val to notifier calls
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*/
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enum cpu_pm_event {
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/* A single cpu is entering a low power state */
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CPU_PM_ENTER,
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/* A single cpu failed to enter a low power state */
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CPU_PM_ENTER_FAILED,
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/* A single cpu is exiting a low power state */
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CPU_PM_EXIT,
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/* A cpu power domain is entering a low power state */
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CPU_CLUSTER_PM_ENTER,
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/* A cpu power domain failed to enter a low power state */
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CPU_CLUSTER_PM_ENTER_FAILED,
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/* A cpu power domain is exiting a low power state */
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CPU_CLUSTER_PM_EXIT,
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};
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#ifdef CONFIG_CPU_PM
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int cpu_pm_register_notifier(struct notifier_block *nb);
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int cpu_pm_unregister_notifier(struct notifier_block *nb);
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int cpu_pm_enter(void);
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int cpu_pm_exit(void);
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int cpu_cluster_pm_enter(void);
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int cpu_cluster_pm_exit(void);
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#else
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static inline int cpu_pm_register_notifier(struct notifier_block *nb)
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{
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return 0;
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}
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static inline int cpu_pm_unregister_notifier(struct notifier_block *nb)
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{
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return 0;
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}
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static inline int cpu_pm_enter(void)
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{
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return 0;
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}
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static inline int cpu_pm_exit(void)
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{
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return 0;
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}
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static inline int cpu_cluster_pm_enter(void)
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{
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return 0;
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}
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static inline int cpu_cluster_pm_exit(void)
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{
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return 0;
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}
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#endif
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#endif
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