arch/arm64/kernel/cpuidle.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * ARM64 CPU idle arch support
   4  *
   5  * Copyright (C) 2014 ARM Ltd.
   6  * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
   7  */
   8
   9 #include <linux/acpi.h>
  10 #include <linux/cpuidle.h>
  11 #include <linux/cpu_pm.h>
  12 #include <linux/of.h>
  13 #include <linux/of_device.h>
  14
  15 #include <asm/cpuidle.h>
  16 #include <asm/cpu_ops.h>
  17
  18 int arm_cpuidle_init(unsigned int cpu)
  19 {
  20         int ret = -EOPNOTSUPP;
  21
  22         if (cpu_ops[cpu] && cpu_ops[cpu]->cpu_suspend &&
  23                         cpu_ops[cpu]->cpu_init_idle)
  24                 ret = cpu_ops[cpu]->cpu_init_idle(cpu);
  25
  26         return ret;
  27 }
  28
  29 /**
  30  * arm_cpuidle_suspend() - function to enter a low-power idle state
  31  * @arg: argument to pass to CPU suspend operations
  32  *
  33  * Return: 0 on success, -EOPNOTSUPP if CPU suspend hook not initialized, CPU
  34  * operations back-end error code otherwise.
  35  */
  36 int arm_cpuidle_suspend(int index)
  37 {
  38         int cpu = smp_processor_id();
  39
  40         return cpu_ops[cpu]->cpu_suspend(index);
  41 }
  42
  43 #ifdef CONFIG_ACPI
  44
  45 #include <acpi/processor.h>
  46
  47 #define ARM64_LPI_IS_RETENTION_STATE(arch_flags) (!(arch_flags))
  48
  49 int acpi_processor_ffh_lpi_probe(unsigned int cpu)
  50 {
  51         return arm_cpuidle_init(cpu);
  52 }
  53
  54 int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
  55 {
  56         if (ARM64_LPI_IS_RETENTION_STATE(lpi->arch_flags))
  57                 return CPU_PM_CPU_IDLE_ENTER_RETENTION(arm_cpuidle_suspend,
  58                                                 lpi->index);
  59         else
  60                 return CPU_PM_CPU_IDLE_ENTER(arm_cpuidle_suspend, lpi->index);
  61 }
  62 #endif