LXR linux/include/linux/cpu

   1/* SPDX-License-Identifier: GPL-2.0-only */
   2/*
   3 * Copyright (C) 2011 Google, Inc.
   4 *
   5 * Author:
   6 *      Colin Cross <ccross@android.com>
   7 */
   8
   9#ifndef _LINUX_CPU_PM_H
  10#define _LINUX_CPU_PM_H
  11
  12#include <linux/kernel.h>
  13#include <linux/notifier.h>
  14
  15/*
  16 * When a CPU goes to a low power state that turns off power to the CPU's
  17 * power domain, the contents of some blocks (floating point coprocessors,
  18 * interrupt controllers, caches, timers) in the same power domain can
  19 * be lost.  The cpm_pm notifiers provide a method for platform idle, suspend,
  20 * and hotplug implementations to notify the drivers for these blocks that
  21 * they may be reset.
  22 *
  23 * All cpu_pm notifications must be called with interrupts disabled.
  24 *
  25 * The notifications are split into two classes: CPU notifications and CPU
  26 * cluster notifications.
  27 *
  28 * CPU notifications apply to a single CPU and must be called on the affected
  29 * CPU.  They are used to save per-cpu context for affected blocks.
  30 *
  31 * CPU cluster notifications apply to all CPUs in a single power domain. They
  32 * are used to save any global context for affected blocks, and must be called
  33 * after all the CPUs in the power domain have been notified of the low power
  34 * state.
  35 */
  36
  37/*
  38 * Event codes passed as unsigned long val to notifier calls
  39 */
  40enum cpu_pm_event {
  41        /* A single cpu is entering a low power state */
  42        CPU_PM_ENTER,
  43
  44        /* A single cpu failed to enter a low power state */
  45        CPU_PM_ENTER_FAILED,
  46
  47        /* A single cpu is exiting a low power state */
  48        CPU_PM_EXIT,
  49
  50        /* A cpu power domain is entering a low power state */
  51        CPU_CLUSTER_PM_ENTER,
  52
  53        /* A cpu power domain failed to enter a low power state */
  54        CPU_CLUSTER_PM_ENTER_FAILED,
  55
  56        /* A cpu power domain is exiting a low power state */
  57        CPU_CLUSTER_PM_EXIT,
  58};
  59
  60#ifdef CONFIG_CPU_PM
  61int cpu_pm_register_notifier(struct notifier_block *nb);
  62int cpu_pm_unregister_notifier(struct notifier_block *nb);
  63int cpu_pm_enter(void);
  64int cpu_pm_exit(void);
  65int cpu_cluster_pm_enter(void);
  66int cpu_cluster_pm_exit(void);
  67
  68#else
  69
  70static inline int cpu_pm_register_notifier(struct notifier_block *nb)
  71{
  72        return 0;
  73}
  74
  75static inline int cpu_pm_unregister_notifier(struct notifier_block *nb)
  76{
  77        return 0;
  78}
  79
  80static inline int cpu_pm_enter(void)
  81{
  82        return 0;
  83}
  84
  85static inline int cpu_pm_exit(void)
  86{
  87        return 0;
  88}
  89
  90static inline int cpu_cluster_pm_enter(void)
  91{
  92        return 0;
  93}
  94
  95static inline int cpu_cluster_pm_exit(void)
  96{
  97        return 0;
  98}
  99#endif
 100#endif
 101