arch/arm/mach-exynos/cpuidle.c

   1 /* linux/arch/arm/mach-exynos4/cpuidle.c
   2  *
   3  * Copyright (c) 2011 Samsung Electronics Co., Ltd.
   4  *              http://www.samsung.com
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9 */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/cpuidle.h>
  14 #include <linux/io.h>
  15
  16 #include <asm/proc-fns.h>
  17
  18 static int exynos4_enter_idle(struct cpuidle_device *dev,
  19                         struct cpuidle_driver *drv,
  20                               int index);
  21
  22 static struct cpuidle_state exynos4_cpuidle_set[] = {
  23         [0] = {
  24                 .enter                  = exynos4_enter_idle,
  25                 .exit_latency           = 1,
  26                 .target_residency       = 100000,
  27                 .flags                  = CPUIDLE_FLAG_TIME_VALID,
  28                 .name                   = "IDLE",
  29                 .desc                   = "ARM clock gating(WFI)",
  30         },
  31 };
  32
  33 static DEFINE_PER_CPU(struct cpuidle_device, exynos4_cpuidle_device);
  34
  35 static struct cpuidle_driver exynos4_idle_driver = {
  36         .name           = "exynos4_idle",
  37         .owner          = THIS_MODULE,
  38 };
  39
  40 static int exynos4_enter_idle(struct cpuidle_device *dev,
  41                                 struct cpuidle_driver *drv,
  42                               int index)
  43 {
  44         struct timeval before, after;
  45         int idle_time;
  46
  47         local_irq_disable();
  48         do_gettimeofday(&before);
  49
  50         cpu_do_idle();
  51
  52         do_gettimeofday(&after);
  53         local_irq_enable();
  54         idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC +
  55                     (after.tv_usec - before.tv_usec);
  56
  57         dev->last_residency = idle_time;
  58         return index;
  59 }
  60
  61 static int __init exynos4_init_cpuidle(void)
  62 {
  63         int i, max_cpuidle_state, cpu_id;
  64         struct cpuidle_device *device;
  65         struct cpuidle_driver *drv = &exynos4_idle_driver;
  66
  67         /* Setup cpuidle driver */
  68         drv->state_count = (sizeof(exynos4_cpuidle_set) /
  69                                        sizeof(struct cpuidle_state));
  70         max_cpuidle_state = drv->state_count;
  71         for (i = 0; i < max_cpuidle_state; i++) {
  72                 memcpy(&drv->states[i], &exynos4_cpuidle_set[i],
  73                                 sizeof(struct cpuidle_state));
  74         }
  75         cpuidle_register_driver(&exynos4_idle_driver);
  76
  77         for_each_cpu(cpu_id, cpu_online_mask) {
  78                 device = &per_cpu(exynos4_cpuidle_device, cpu_id);
  79                 device->cpu = cpu_id;
  80
  81                 device->state_count = drv->state_count;
  82
  83                 if (cpuidle_register_device(device)) {
  84                         printk(KERN_ERR "CPUidle register device failed\n,");
  85                         return -EIO;
  86                 }
  87         }
  88         return 0;
  89 }
  90 device_initcall(exynos4_init_cpuidle);