// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2011-2014 Samsung Electronics Co., Ltd.
 *              http://www.samsung.com
 *
 * Coupled cpuidle support based on the work of:
 *      Colin Cross <ccross@android.com>
 *      Daniel Lezcano <daniel.lezcano@linaro.org>
*/

#include <linux/cpuidle.h>
#include <linux/cpu_pm.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/platform_data/cpuidle-exynos.h>

#include <asm/suspend.h>
#include <asm/cpuidle.h>

static atomic_t exynos_idle_barrier;

static struct cpuidle_exynos_data *exynos_cpuidle_pdata;
static void (*exynos_enter_aftr)(void);

static int exynos_enter_coupled_lowpower(struct cpuidle_device *dev,
                                         struct cpuidle_driver *drv,
                                         int index)
{
        int ret;

        exynos_cpuidle_pdata->pre_enter_aftr();

        /*
         * Waiting all cpus to reach this point at the same moment
         */
        cpuidle_coupled_parallel_barrier(dev, &exynos_idle_barrier);

        /*
         * Both cpus will reach this point at the same time
         */
        ret = dev->cpu ? exynos_cpuidle_pdata->cpu1_powerdown()
                       : exynos_cpuidle_pdata->cpu0_enter_aftr();
        if (ret)
                index = ret;

        /*
         * Waiting all cpus to finish the power sequence before going further
         */
        cpuidle_coupled_parallel_barrier(dev, &exynos_idle_barrier);

        exynos_cpuidle_pdata->post_enter_aftr();

        return index;
}

static int exynos_enter_lowpower(struct cpuidle_device *dev,
                                struct cpuidle_driver *drv,
                                int index)
{
        int new_index = index;

        /* AFTR can only be entered when cores other than CPU0 are offline */
        if (num_online_cpus() > 1 || dev->cpu != 0)
                new_index = drv->safe_state_index;

        if (new_index == 0)
                return arm_cpuidle_simple_enter(dev, drv, new_index);

        exynos_enter_aftr();

        return new_index;
}

static struct cpuidle_driver exynos_idle_driver = {
        .name                   = "exynos_idle",
        .owner                  = THIS_MODULE,
        .states = {
                [0] = ARM_CPUIDLE_WFI_STATE,
                [1] = {
                        .enter                  = exynos_enter_lowpower,
                        .exit_latency           = 300,
                        .target_residency       = 10000,
                        .name                   = "C1",
                        .desc                   = "ARM power down",
                },
        },
        .state_count = 2,
        .safe_state_index = 0,
};

static struct cpuidle_driver exynos_coupled_idle_driver = {
        .name                   = "exynos_coupled_idle",
        .owner                  = THIS_MODULE,
        .states = {
                [0] = ARM_CPUIDLE_WFI_STATE,
                [1] = {
                        .enter                  = exynos_enter_coupled_lowpower,
                        .exit_latency           = 5000,
                        .target_residency       = 10000,
                        .flags                  = CPUIDLE_FLAG_COUPLED |
                                                  CPUIDLE_FLAG_TIMER_STOP,
                        .name                   = "C1",
                        .desc                   = "ARM power down",
                },
        },
        .state_count = 2,
        .safe_state_index = 0,
};

static int exynos_cpuidle_probe(struct platform_device *pdev)
{
        int ret;

        if (IS_ENABLED(CONFIG_SMP) &&
            (of_machine_is_compatible("samsung,exynos4210") ||
             of_machine_is_compatible("samsung,exynos3250"))) {
                exynos_cpuidle_pdata = pdev->dev.platform_data;

                ret = cpuidle_register(&exynos_coupled_idle_driver,
                                       cpu_possible_mask);
        } else {
                exynos_enter_aftr = (void *)(pdev->dev.platform_data);

                ret = cpuidle_register(&exynos_idle_driver, NULL);
        }

        if (ret) {
                dev_err(&pdev->dev, "failed to register cpuidle driver\n");
                return ret;
        }

        return 0;
}

static struct platform_driver exynos_cpuidle_driver = {
        .probe  = exynos_cpuidle_probe,
        .driver = {
                .name = "exynos_cpuidle",
        },
};
builtin_platform_driver(exynos_cpuidle_driver);