// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * AppliedMicro X-Gene SoC Reboot Driver
 *
 * Copyright (c) 2013, Applied Micro Circuits Corporation
 * Author: Feng Kan <fkan@apm.com>
 * Author: Loc Ho <lho@apm.com>
 *
 * This driver provides system reboot functionality for APM X-Gene SoC.
 * For system shutdown, this is board specify. If a board designer
 * implements GPIO shutdown, use the gpio-poweroff.c driver.
 */
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/notifier.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/stat.h>
#include <linux/slab.h>

struct xgene_reboot_context {
        struct device *dev;
        void __iomem *csr;
        u32 mask;
};

static int xgene_restart_handler(struct sys_off_data *data)
{
        struct xgene_reboot_context *ctx = data->cb_data;

        /* Issue the reboot */
        writel(ctx->mask, ctx->csr);

        mdelay(1000);

        dev_emerg(ctx->dev, "Unable to restart system\n");

        return NOTIFY_DONE;
}

static int xgene_reboot_probe(struct platform_device *pdev)
{
        struct xgene_reboot_context *ctx;
        struct device *dev = &pdev->dev;
        int err;

        ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
        if (!ctx)
                return -ENOMEM;

        ctx->csr = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(ctx->csr)) {
                dev_err(dev, "can not map resource\n");
                return PTR_ERR(ctx->csr);
        }

        if (of_property_read_u32(dev->of_node, "mask", &ctx->mask))
                ctx->mask = 0xFFFFFFFF;

        ctx->dev = dev;
        err = devm_register_sys_off_handler(dev, SYS_OFF_MODE_RESTART, 128,
                                            xgene_restart_handler, ctx);
        if (err)
                dev_err(dev, "cannot register restart handler (err=%d)\n", err);

        return err;
}

static const struct of_device_id xgene_reboot_of_match[] = {
        { .compatible = "apm,xgene-reboot" },
        {}
};

static struct platform_driver xgene_reboot_driver = {
        .probe = xgene_reboot_probe,
        .driver = {
                .name = "xgene-reboot",
                .of_match_table = xgene_reboot_of_match,
        },
};
builtin_platform_driver(xgene_reboot_driver);