LXR linux/arch/arm64/kernel/cpuidle.c

   1/*
   2 * ARM64 CPU idle arch support
   3 *
   4 * Copyright (C) 2014 ARM Ltd.
   5 * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License version 2 as
   9 * published by the Free Software Foundation.
  10 */
  11
  12#include <linux/acpi.h>
  13#include <linux/cpuidle.h>
  14#include <linux/cpu_pm.h>
  15#include <linux/of.h>
  16#include <linux/of_device.h>
  17
  18#include <asm/cpuidle.h>
  19#include <asm/cpu_ops.h>
  20
  21int arm_cpuidle_init(unsigned int cpu)
  22{
  23        int ret = -EOPNOTSUPP;
  24
  25        if (cpu_ops[cpu] && cpu_ops[cpu]->cpu_suspend &&
  26                        cpu_ops[cpu]->cpu_init_idle)
  27                ret = cpu_ops[cpu]->cpu_init_idle(cpu);
  28
  29        return ret;
  30}
  31
  32/**
  33 * arm_cpuidle_suspend() - function to enter a low-power idle state
  34 * @arg: argument to pass to CPU suspend operations
  35 *
  36 * Return: 0 on success, -EOPNOTSUPP if CPU suspend hook not initialized, CPU
  37 * operations back-end error code otherwise.
  38 */
  39int arm_cpuidle_suspend(int index)
  40{
  41        int cpu = smp_processor_id();
  42
  43        return cpu_ops[cpu]->cpu_suspend(index);
  44}
  45
  46#ifdef CONFIG_ACPI
  47
  48#include <acpi/processor.h>
  49
  50#define ARM64_LPI_IS_RETENTION_STATE(arch_flags) (!(arch_flags))
  51
  52int acpi_processor_ffh_lpi_probe(unsigned int cpu)
  53{
  54        return arm_cpuidle_init(cpu);
  55}
  56
  57int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
  58{
  59        if (ARM64_LPI_IS_RETENTION_STATE(lpi->arch_flags))
  60                return CPU_PM_CPU_IDLE_ENTER_RETENTION(arm_cpuidle_suspend,
  61                                                lpi->index);
  62        else
  63                return CPU_PM_CPU_IDLE_ENTER(arm_cpuidle_suspend, lpi->index);
  64}
  65#endif
  66