drivers/cpuidle/cpuidle-exynos.c

   1 /*
   2  * Copyright (c) 2011-2014 Samsung Electronics Co., Ltd.
   3  *              http://www.samsung.com
   4  *
   5  * Coupled cpuidle support based on the work of:
   6  *      Colin Cross <ccross@android.com>
   7  *      Daniel Lezcano <daniel.lezcano@linaro.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12 */
  13
  14 #include <linux/cpuidle.h>
  15 #include <linux/cpu_pm.h>
  16 #include <linux/export.h>
  17 #include <linux/module.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/of.h>
  20 #include <linux/platform_data/cpuidle-exynos.h>
  21
  22 #include <asm/suspend.h>
  23 #include <asm/cpuidle.h>
  24
  25 static atomic_t exynos_idle_barrier;
  26
  27 static struct cpuidle_exynos_data *exynos_cpuidle_pdata;
  28 static void (*exynos_enter_aftr)(void);
  29
  30 static int exynos_enter_coupled_lowpower(struct cpuidle_device *dev,
  31                                          struct cpuidle_driver *drv,
  32                                          int index)
  33 {
  34         int ret;
  35
  36         exynos_cpuidle_pdata->pre_enter_aftr();
  37
  38         /*
  39          * Waiting all cpus to reach this point at the same moment
  40          */
  41         cpuidle_coupled_parallel_barrier(dev, &exynos_idle_barrier);
  42
  43         /*
  44          * Both cpus will reach this point at the same time
  45          */
  46         ret = dev->cpu ? exynos_cpuidle_pdata->cpu1_powerdown()
  47                        : exynos_cpuidle_pdata->cpu0_enter_aftr();
  48         if (ret)
  49                 index = ret;
  50
  51         /*
  52          * Waiting all cpus to finish the power sequence before going further
  53          */
  54         cpuidle_coupled_parallel_barrier(dev, &exynos_idle_barrier);
  55
  56         exynos_cpuidle_pdata->post_enter_aftr();
  57
  58         return index;
  59 }
  60
  61 static int exynos_enter_lowpower(struct cpuidle_device *dev,
  62                                 struct cpuidle_driver *drv,
  63                                 int index)
  64 {
  65         int new_index = index;
  66
  67         /* AFTR can only be entered when cores other than CPU0 are offline */
  68         if (num_online_cpus() > 1 || dev->cpu != 0)
  69                 new_index = drv->safe_state_index;
  70
  71         if (new_index == 0)
  72                 return arm_cpuidle_simple_enter(dev, drv, new_index);
  73
  74         exynos_enter_aftr();
  75
  76         return new_index;
  77 }
  78
  79 static struct cpuidle_driver exynos_idle_driver = {
  80         .name                   = "exynos_idle",
  81         .owner                  = THIS_MODULE,
  82         .states = {
  83                 [0] = ARM_CPUIDLE_WFI_STATE,
  84                 [1] = {
  85                         .enter                  = exynos_enter_lowpower,
  86                         .exit_latency           = 300,
  87                         .target_residency       = 100000,
  88                         .name                   = "C1",
  89                         .desc                   = "ARM power down",
  90                 },
  91         },
  92         .state_count = 2,
  93         .safe_state_index = 0,
  94 };
  95
  96 static struct cpuidle_driver exynos_coupled_idle_driver = {
  97         .name                   = "exynos_coupled_idle",
  98         .owner                  = THIS_MODULE,
  99         .states = {
 100                 [0] = ARM_CPUIDLE_WFI_STATE,
 101                 [1] = {
 102                         .enter                  = exynos_enter_coupled_lowpower,
 103                         .exit_latency           = 5000,
 104                         .target_residency       = 10000,
 105                         .flags                  = CPUIDLE_FLAG_COUPLED |
 106                                                   CPUIDLE_FLAG_TIMER_STOP,
 107                         .name                   = "C1",
 108                         .desc                   = "ARM power down",
 109                 },
 110         },
 111         .state_count = 2,
 112         .safe_state_index = 0,
 113 };
 114
 115 static int exynos_cpuidle_probe(struct platform_device *pdev)
 116 {
 117         int ret;
 118
 119         if (of_machine_is_compatible("samsung,exynos4210")) {
 120                 exynos_cpuidle_pdata = pdev->dev.platform_data;
 121
 122                 ret = cpuidle_register(&exynos_coupled_idle_driver,
 123                                        cpu_possible_mask);
 124         } else {
 125                 exynos_enter_aftr = (void *)(pdev->dev.platform_data);
 126
 127                 ret = cpuidle_register(&exynos_idle_driver, NULL);
 128         }
 129
 130         if (ret) {
 131                 dev_err(&pdev->dev, "failed to register cpuidle driver\n");
 132                 return ret;
 133         }
 134
 135         return 0;
 136 }
 137
 138 static struct platform_driver exynos_cpuidle_driver = {
 139         .probe  = exynos_cpuidle_probe,
 140         .driver = {
 141                 .name = "exynos_cpuidle",
 142         },
 143 };
 144
 145 module_platform_driver(exynos_cpuidle_driver);