// SPDX-License-Identifier: GPL-2.0-only
// Copyright (C) 2016 Broadcom

#include <linux/io.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>

#define RSTMGR_REG_WR_ACCESS_OFFSET     0
#define RSTMGR_REG_CHIP_SOFT_RST_OFFSET 4

#define RSTMGR_WR_PASSWORD              0xa5a5
#define RSTMGR_WR_PASSWORD_SHIFT        8
#define RSTMGR_WR_ACCESS_ENABLE         1

static void __iomem *kona_reset_base;

static int kona_reset_handler(struct sys_off_data *data)
{
        /*
         * A soft reset is triggered by writing a 0 to bit 0 of the soft reset
         * register. To write to that register we must first write the password
         * and the enable bit in the write access enable register.
         */
        writel((RSTMGR_WR_PASSWORD << RSTMGR_WR_PASSWORD_SHIFT) |
                RSTMGR_WR_ACCESS_ENABLE,
                kona_reset_base + RSTMGR_REG_WR_ACCESS_OFFSET);
        writel(0, kona_reset_base + RSTMGR_REG_CHIP_SOFT_RST_OFFSET);

        return NOTIFY_DONE;
}

static int kona_reset_probe(struct platform_device *pdev)
{
        kona_reset_base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(kona_reset_base))
                return PTR_ERR(kona_reset_base);

        return devm_register_sys_off_handler(&pdev->dev, SYS_OFF_MODE_RESTART,
                                             128, kona_reset_handler, NULL);
}

static const struct of_device_id of_match[] = {
        { .compatible = "brcm,bcm21664-resetmgr" },
        {},
};

static struct platform_driver bcm_kona_reset_driver = {
        .probe = kona_reset_probe,
        .driver = {
                .name = "brcm-kona-reset",
                .of_match_table = of_match,
        },
};

builtin_platform_driver(bcm_kona_reset_driver);