linux/drivers/cpuidle/cpuidle-exynos.c
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   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/init.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
  25static atomic_t exynos_idle_barrier;
  26
  27static struct cpuidle_exynos_data *exynos_cpuidle_pdata;
  28static void (*exynos_enter_aftr)(void);
  29
  30static 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
  61static 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
  79static 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
  96static 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
 115static int exynos_cpuidle_probe(struct platform_device *pdev)
 116{
 117        int ret;
 118
 119        if (IS_ENABLED(CONFIG_SMP) &&
 120            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
 139static struct platform_driver exynos_cpuidle_driver = {
 140        .probe  = exynos_cpuidle_probe,
 141        .driver = {
 142                .name = "exynos_cpuidle",
 143        },
 144};
 145builtin_platform_driver(exynos_cpuidle_driver);
 146
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