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/proc-fns.h>
  23 #include <asm/suspend.h>
  24 #include <asm/cpuidle.h>
  25
  26 static atomic_t exynos_idle_barrier;
  27
  28 static struct cpuidle_exynos_data *exynos_cpuidle_pdata;
  29 static void (*exynos_enter_aftr)(void);
  30
  31 static int exynos_enter_coupled_lowpower(struct cpuidle_device *dev,
  32                                          struct cpuidle_driver *drv,
  33                                          int index)
  34 {
  35         int ret;
  36
  37         exynos_cpuidle_pdata->pre_enter_aftr();
  38
  39         /*
  40          * Waiting all cpus to reach this point at the same moment
  41          */
  42         cpuidle_coupled_parallel_barrier(dev, &exynos_idle_barrier);
  43
  44         /*
  45          * Both cpus will reach this point at the same time
  46          */
  47         ret = dev->cpu ? exynos_cpuidle_pdata->cpu1_powerdown()
  48                        : exynos_cpuidle_pdata->cpu0_enter_aftr();
  49         if (ret)
  50                 index = ret;
  51
  52         /*
  53          * Waiting all cpus to finish the power sequence before going further
  54          */
  55         cpuidle_coupled_parallel_barrier(dev, &exynos_idle_barrier);
  56
  57         exynos_cpuidle_pdata->post_enter_aftr();
  58
  59         return index;
  60 }
  61
  62 static int exynos_enter_lowpower(struct cpuidle_device *dev,
  63                                 struct cpuidle_driver *drv,
  64                                 int index)
  65 {
  66         int new_index = index;
  67
  68         /* AFTR can only be entered when cores other than CPU0 are offline */
  69         if (num_online_cpus() > 1 || dev->cpu != 0)
  70                 new_index = drv->safe_state_index;
  71
  72         if (new_index == 0)
  73                 return arm_cpuidle_simple_enter(dev, drv, new_index);
  74
  75         exynos_enter_aftr();
  76
  77         return new_index;
  78 }
  79
  80 static struct cpuidle_driver exynos_idle_driver = {
  81         .name                   = "exynos_idle",
  82         .owner                  = THIS_MODULE,
  83         .states = {
  84                 [0] = ARM_CPUIDLE_WFI_STATE,
  85                 [1] = {
  86                         .enter                  = exynos_enter_lowpower,
  87                         .exit_latency           = 300,
  88                         .target_residency       = 100000,
  89                         .name                   = "C1",
  90                         .desc                   = "ARM power down",
  91                 },
  92         },
  93         .state_count = 2,
  94         .safe_state_index = 0,
  95 };
  96
  97 static struct cpuidle_driver exynos_coupled_idle_driver = {
  98         .name                   = "exynos_coupled_idle",
  99         .owner                  = THIS_MODULE,
 100         .states = {
 101                 [0] = ARM_CPUIDLE_WFI_STATE,
 102                 [1] = {
 103                         .enter                  = exynos_enter_coupled_lowpower,
 104                         .exit_latency           = 5000,
 105                         .target_residency       = 10000,
 106                         .flags                  = CPUIDLE_FLAG_COUPLED |
 107                                                   CPUIDLE_FLAG_TIMER_STOP,
 108                         .name                   = "C1",
 109                         .desc                   = "ARM power down",
 110                 },
 111         },
 112         .state_count = 2,
 113         .safe_state_index = 0,
 114 };
 115
 116 static int exynos_cpuidle_probe(struct platform_device *pdev)
 117 {
 118         int ret;
 119
 120         if (of_machine_is_compatible("samsung,exynos4210")) {
 121                 exynos_cpuidle_pdata = pdev->dev.platform_data;
 122
 123                 ret = cpuidle_register(&exynos_coupled_idle_driver,
 124                                        cpu_possible_mask);
 125         } else {
 126                 exynos_enter_aftr = (void *)(pdev->dev.platform_data);
 127
 128                 ret = cpuidle_register(&exynos_idle_driver, NULL);
 129         }
 130
 131         if (ret) {
 132                 dev_err(&pdev->dev, "failed to register cpuidle driver\n");
 133                 return ret;
 134         }
 135
 136         return 0;
 137 }
 138
 139 static struct platform_driver exynos_cpuidle_driver = {
 140         .probe  = exynos_cpuidle_probe,
 141         .driver = {
 142                 .name = "exynos_cpuidle",
 143         },
 144 };
 145
 146 module_platform_driver(exynos_cpuidle_driver);