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/of.h>
  13 #include <linux/of_device.h>
  14
  15 #include <asm/cpuidle.h>
  16 #include <asm/cpu_ops.h>
  17
  18 int __init arm_cpuidle_init(unsigned int cpu)
  19 {
  20         int ret = -EOPNOTSUPP;
  21
  22         if (cpu_ops[cpu] && cpu_ops[cpu]->cpu_init_idle)
  23                 ret = cpu_ops[cpu]->cpu_init_idle(cpu);
  24
  25         return ret;
  26 }
  27
  28 /**
  29  * cpu_suspend() - function to enter a low-power idle state
  30  * @arg: argument to pass to CPU suspend operations
  31  *
  32  * Return: 0 on success, -EOPNOTSUPP if CPU suspend hook not initialized, CPU
  33  * operations back-end error code otherwise.
  34  */
  35 int arm_cpuidle_suspend(int index)
  36 {
  37         int cpu = smp_processor_id();
  38
  39         /*
  40          * If cpu_ops have not been registered or suspend
  41          * has not been initialized, cpu_suspend call fails early.
  42          */
  43         if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_suspend)
  44                 return -EOPNOTSUPP;
  45         return cpu_ops[cpu]->cpu_suspend(index);
  46 }