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
  21 int 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  */
  39 int 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
  52 int acpi_processor_ffh_lpi_probe(unsigned int cpu)
  53 {
  54         return arm_cpuidle_init(cpu);
  55 }
  56
  57 int 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