// SPDX-License-Identifier: GPL-2.0
/*
 * Renesas R-Mobile Reset Driver
 *
 * Copyright (C) 2014 Glider bvba
 */

#include <linux/io.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/printk.h>
#include <linux/reboot.h>

/* SYSC Register Bank 2 */
#define RESCNT2         0x20            /* Reset Control Register 2 */

/* Reset Control Register 2 */
#define RESCNT2_PRES    0x80000000      /* Soft power-on reset */

static int rmobile_reset_handler(struct sys_off_data *data)
{
        void __iomem *sysc_base2 = (void __iomem *)data->cb_data;

        /* Let's assume we have acquired the HPB semaphore */
        writel(RESCNT2_PRES, sysc_base2 + RESCNT2);

        return NOTIFY_DONE;
}

static int rmobile_reset_probe(struct platform_device *pdev)
{
        void __iomem *sysc_base2;
        int error;

        sysc_base2 = devm_platform_ioremap_resource(pdev, 1);
        if (IS_ERR(sysc_base2))
                return PTR_ERR(sysc_base2);

        error = devm_register_sys_off_handler(&pdev->dev,
                                              SYS_OFF_MODE_RESTART,
                                              SYS_OFF_PRIO_HIGH,
                                              rmobile_reset_handler,
                                              (__force void *)sysc_base2);
        if (error) {
                dev_err(&pdev->dev,
                        "cannot register restart handler (err=%d)\n", error);
                return error;
        }

        return 0;
}

static const struct of_device_id rmobile_reset_of_match[] = {
        { .compatible = "renesas,sysc-rmobile", },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, rmobile_reset_of_match);

static struct platform_driver rmobile_reset_driver = {
        .probe = rmobile_reset_probe,
        .driver = {
                .name = "rmobile_reset",
                .of_match_table = rmobile_reset_of_match,
        },
};

module_platform_driver(rmobile_reset_driver);

MODULE_DESCRIPTION("Renesas R-Mobile Reset Driver");
MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
MODULE_LICENSE("GPL v2");