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 cpu_init_idle(unsigned int cpu)
  19 {
  20         int ret = -EOPNOTSUPP;
  21         struct device_node *cpu_node = of_cpu_device_node_get(cpu);
  22
  23         if (!cpu_node)
  24                 return -ENODEV;
  25
  26         if (cpu_ops[cpu] && cpu_ops[cpu]->cpu_init_idle)
  27                 ret = cpu_ops[cpu]->cpu_init_idle(cpu_node, cpu);
  28
  29         of_node_put(cpu_node);
  30         return ret;
  31 }
  32
  33 /**
  34  * cpu_suspend() - function to enter a low-power idle state
  35  * @arg: argument to pass to CPU suspend operations
  36  *
  37  * Return: 0 on success, -EOPNOTSUPP if CPU suspend hook not initialized, CPU
  38  * operations back-end error code otherwise.
  39  */
  40 int cpu_suspend(unsigned long arg)
  41 {
  42         int cpu = smp_processor_id();
  43
  44         /*
  45          * If cpu_ops have not been registered or suspend
  46          * has not been initialized, cpu_suspend call fails early.
  47          */
  48         if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_suspend)
  49                 return -EOPNOTSUPP;
  50         return cpu_ops[cpu]->cpu_suspend(arg);
  51 }