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 idle_finisher(unsigned long flags)
  24 {
  25         exynos_enter_aftr();
  26         cpu_do_idle();
  27
  28         return 1;
  29 }
  30
  31 static int exynos_enter_core0_aftr(struct cpuidle_device *dev,
  32                                 struct cpuidle_driver *drv,
  33                                 int index)
  34 {
  35         cpu_pm_enter();
  36         cpu_suspend(0, idle_finisher);
  37         cpu_pm_exit();
  38
  39         return index;
  40 }
  41
  42 static int exynos_enter_lowpower(struct cpuidle_device *dev,
  43                                 struct cpuidle_driver *drv,
  44                                 int index)
  45 {
  46         int new_index = index;
  47
  48         /* AFTR can only be entered when cores other than CPU0 are offline */
  49         if (num_online_cpus() > 1 || dev->cpu != 0)
  50                 new_index = drv->safe_state_index;
  51
  52         if (new_index == 0)
  53                 return arm_cpuidle_simple_enter(dev, drv, new_index);
  54         else
  55                 return exynos_enter_core0_aftr(dev, drv, new_index);
  56 }
  57
  58 static struct cpuidle_driver exynos_idle_driver = {
  59         .name                   = "exynos_idle",
  60         .owner                  = THIS_MODULE,
  61         .states = {
  62                 [0] = ARM_CPUIDLE_WFI_STATE,
  63                 [1] = {
  64                         .enter                  = exynos_enter_lowpower,
  65                         .exit_latency           = 300,
  66                         .target_residency       = 100000,
  67                         .flags                  = CPUIDLE_FLAG_TIME_VALID,
  68                         .name                   = "C1",
  69                         .desc                   = "ARM power down",
  70                 },
  71         },
  72         .state_count = 2,
  73         .safe_state_index = 0,
  74 };
  75
  76 static int exynos_cpuidle_probe(struct platform_device *pdev)
  77 {
  78         int ret;
  79
  80         exynos_enter_aftr = (void *)(pdev->dev.platform_data);
  81
  82         ret = cpuidle_register(&exynos_idle_driver, NULL);
  83         if (ret) {
  84                 dev_err(&pdev->dev, "failed to register cpuidle driver\n");
  85                 return ret;
  86         }
  87
  88         return 0;
  89 }
  90
  91 static struct platform_driver exynos_cpuidle_driver = {
  92         .probe  = exynos_cpuidle_probe,
  93         .driver = {
  94                 .name = "exynos_cpuidle",
  95                 .owner = THIS_MODULE,
  96         },
  97 };
  98
  99 module_platform_driver(exynos_cpuidle_driver);