drivers/cpuidle/cpuidle-exynos.c

   1 /* linux/arch/arm/mach-exynos/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/cpuidle.h>
  12 #include <linux/cpu_pm.h>
  13 #include <linux/export.h>
  14 #include <linux/module.h>
  15 #include <linux/platform_device.h>
  16
  17 #include <asm/proc-fns.h>
  18 #include <asm/suspend.h>
  19 #include <asm/cpuidle.h>
  20
  21 static void (*exynos_enter_aftr)(void);
  22
  23 static int exynos_enter_lowpower(struct cpuidle_device *dev,
  24                                 struct cpuidle_driver *drv,
  25                                 int index)
  26 {
  27         int new_index = index;
  28
  29         /* AFTR can only be entered when cores other than CPU0 are offline */
  30         if (num_online_cpus() > 1 || dev->cpu != 0)
  31                 new_index = drv->safe_state_index;
  32
  33         if (new_index == 0)
  34                 return arm_cpuidle_simple_enter(dev, drv, new_index);
  35
  36         exynos_enter_aftr();
  37
  38         return new_index;
  39 }
  40
  41 static struct cpuidle_driver exynos_idle_driver = {
  42         .name                   = "exynos_idle",
  43         .owner                  = THIS_MODULE,
  44         .states = {
  45                 [0] = ARM_CPUIDLE_WFI_STATE,
  46                 [1] = {
  47                         .enter                  = exynos_enter_lowpower,
  48                         .exit_latency           = 300,
  49                         .target_residency       = 100000,
  50                         .flags                  = CPUIDLE_FLAG_TIME_VALID,
  51                         .name                   = "C1",
  52                         .desc                   = "ARM power down",
  53                 },
  54         },
  55         .state_count = 2,
  56         .safe_state_index = 0,
  57 };
  58
  59 static int exynos_cpuidle_probe(struct platform_device *pdev)
  60 {
  61         int ret;
  62
  63         exynos_enter_aftr = (void *)(pdev->dev.platform_data);
  64
  65         ret = cpuidle_register(&exynos_idle_driver, NULL);
  66         if (ret) {
  67                 dev_err(&pdev->dev, "failed to register cpuidle driver\n");
  68                 return ret;
  69         }
  70
  71         return 0;
  72 }
  73
  74 static struct platform_driver exynos_cpuidle_driver = {
  75         .probe  = exynos_cpuidle_probe,
  76         .driver = {
  77                 .name = "exynos_cpuidle",
  78                 .owner = THIS_MODULE,
  79         },
  80 };
  81
  82 module_platform_driver(exynos_cpuidle_driver);