[linux.git] / include / linux / cpu_pm.h

/*
 * Copyright (C) 2011 Google, Inc.
 *
 * Author:
 *	Colin Cross <[email protected]>
 *
 * 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
Commit	Line	Data
ab10023e CC	1	/*
	2	* Copyright (C) 2011 Google, Inc.
	3	*
	4	* Author:
	5	* Colin Cross <[email protected]>
	6	*
	7	* This software is licensed under the terms of the GNU General Public
	8	* License version 2, as published by the Free Software Foundation, and
	9	* may be copied, distributed, and modified under those terms.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	*/
	17
	18	#ifndef _LINUX_CPU_PM_H
	19	#define _LINUX_CPU_PM_H
	20
	21	#include <linux/kernel.h>
	22	#include <linux/notifier.h>
	23
	24	/*
	25	* When a CPU goes to a low power state that turns off power to the CPU's
	26	* power domain, the contents of some blocks (floating point coprocessors,
	27	* interrupt controllers, caches, timers) in the same power domain can
	28	* be lost. The cpm_pm notifiers provide a method for platform idle, suspend,
	29	* and hotplug implementations to notify the drivers for these blocks that
	30	* they may be reset.
	31	*
	32	* All cpu_pm notifications must be called with interrupts disabled.
	33	*
	34	* The notifications are split into two classes: CPU notifications and CPU
	35	* cluster notifications.
	36	*
	37	* CPU notifications apply to a single CPU and must be called on the affected
	38	* CPU. They are used to save per-cpu context for affected blocks.
	39	*
	40	* CPU cluster notifications apply to all CPUs in a single power domain. They
	41	* are used to save any global context for affected blocks, and must be called
	42	* after all the CPUs in the power domain have been notified of the low power
	43	* state.
	44	*/
	45
	46	/*
	47	* Event codes passed as unsigned long val to notifier calls
	48	*/
	49	enum cpu_pm_event {
	50	/* A single cpu is entering a low power state */
	51	CPU_PM_ENTER,
	52
	53	/* A single cpu failed to enter a low power state */
	54	CPU_PM_ENTER_FAILED,
	55
	56	/* A single cpu is exiting a low power state */
	57	CPU_PM_EXIT,
	58
	59	/* A cpu power domain is entering a low power state */
	60	CPU_CLUSTER_PM_ENTER,
	61
	62	/* A cpu power domain failed to enter a low power state */
	63	CPU_CLUSTER_PM_ENTER_FAILED,
	64
65	/* A cpu power domain is exiting a low power state */
66	CPU_CLUSTER_PM_EXIT,
67	};
68
69	#ifdef CONFIG_CPU_PM
70	int cpu_pm_register_notifier(struct notifier_block *nb);
71	int cpu_pm_unregister_notifier(struct notifier_block *nb);
72	int cpu_pm_enter(void);
73	int cpu_pm_exit(void);
74	int cpu_cluster_pm_enter(void);
75	int cpu_cluster_pm_exit(void);
76
77	#else
78
79	static inline int cpu_pm_register_notifier(struct notifier_block *nb)
80	{
81	return 0;
82	}
83
84	static inline int cpu_pm_unregister_notifier(struct notifier_block *nb)
85	{
86	return 0;
87	}
88
89	static inline int cpu_pm_enter(void)
90	{
91	return 0;
92	}
93
94	static inline int cpu_pm_exit(void)
95	{
96	return 0;
97	}
98
99	static inline int cpu_cluster_pm_enter(void)
100	{
101	return 0;
102	}
103
104	static inline int cpu_cluster_pm_exit(void)
105	{
106	return 0;
107	}
108	#endif
109	#endif