// SPDX-License-Identifier: (GPL-2.0 OR MIT)
/*
 * Microsemi MIPS SoC reset driver
 *
 * License: Dual MIT/GPL
 * Copyright (c) 2017 Microsemi Corporation
 */
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/notifier.h>
#include <linux/mod_devicetable.h>
#include <linux/mfd/syscon.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/reboot.h>
#include <linux/regmap.h>

struct reset_props {
        const char *syscon;
        u32 protect_reg;
        u32 vcore_protect;
        u32 if_si_owner_bit;
};

struct ocelot_reset_context {
        void __iomem *base;
        struct regmap *cpu_ctrl;
        const struct reset_props *props;
        struct notifier_block restart_handler;
};

#define BIT_OFF_INVALID                         32

#define SOFT_CHIP_RST BIT(0)

#define ICPU_CFG_CPU_SYSTEM_CTRL_GENERAL_CTRL   0x24
#define IF_SI_OWNER_MASK                        GENMASK(1, 0)
#define IF_SI_OWNER_SISL                        0
#define IF_SI_OWNER_SIBM                        1
#define IF_SI_OWNER_SIMC                        2

static int ocelot_restart_handle(struct notifier_block *this,
                                 unsigned long mode, void *cmd)
{
        struct ocelot_reset_context *ctx = container_of(this, struct
                                                        ocelot_reset_context,
                                                        restart_handler);
        u32 if_si_owner_bit = ctx->props->if_si_owner_bit;

        /* Make sure the core is not protected from reset */
        regmap_update_bits(ctx->cpu_ctrl, ctx->props->protect_reg,
                           ctx->props->vcore_protect, 0);

        /* Make the SI back to boot mode */
        if (if_si_owner_bit != BIT_OFF_INVALID)
                regmap_update_bits(ctx->cpu_ctrl,
                                   ICPU_CFG_CPU_SYSTEM_CTRL_GENERAL_CTRL,
                                   IF_SI_OWNER_MASK << if_si_owner_bit,
                                   IF_SI_OWNER_SIBM << if_si_owner_bit);

        pr_emerg("Resetting SoC\n");

        writel(SOFT_CHIP_RST, ctx->base);

        pr_emerg("Unable to restart system\n");
        return NOTIFY_DONE;
}

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

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

        ctx->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(ctx->base))
                return PTR_ERR(ctx->base);

        ctx->props = device_get_match_data(dev);

        ctx->cpu_ctrl = syscon_regmap_lookup_by_compatible(ctx->props->syscon);
        if (IS_ERR(ctx->cpu_ctrl)) {
                dev_err(dev, "No syscon map: %s\n", ctx->props->syscon);
                return PTR_ERR(ctx->cpu_ctrl);
        }

        ctx->restart_handler.notifier_call = ocelot_restart_handle;
        ctx->restart_handler.priority = 192;
        err = register_restart_handler(&ctx->restart_handler);
        if (err)
                dev_err(dev, "can't register restart notifier (err=%d)\n", err);

        return err;
}

static const struct reset_props reset_props_jaguar2 = {
        .syscon          = "mscc,ocelot-cpu-syscon",
        .protect_reg     = 0x20,
        .vcore_protect   = BIT(2),
        .if_si_owner_bit = 6,
};

static const struct reset_props reset_props_luton = {
        .syscon          = "mscc,ocelot-cpu-syscon",
        .protect_reg     = 0x20,
        .vcore_protect   = BIT(2),
        .if_si_owner_bit = BIT_OFF_INVALID, /* n/a */
};

static const struct reset_props reset_props_ocelot = {
        .syscon          = "mscc,ocelot-cpu-syscon",
        .protect_reg     = 0x20,
        .vcore_protect   = BIT(2),
        .if_si_owner_bit = 4,
};

static const struct reset_props reset_props_sparx5 = {
        .syscon          = "microchip,sparx5-cpu-syscon",
        .protect_reg     = 0x84,
        .vcore_protect   = BIT(10),
        .if_si_owner_bit = 6,
};

static const struct of_device_id ocelot_reset_of_match[] = {
        {
                .compatible = "mscc,jaguar2-chip-reset",
                .data = &reset_props_jaguar2
        }, {
                .compatible = "mscc,luton-chip-reset",
                .data = &reset_props_luton
        }, {
                .compatible = "mscc,ocelot-chip-reset",
                .data = &reset_props_ocelot
        }, {
                .compatible = "microchip,sparx5-chip-reset",
                .data = &reset_props_sparx5
        },
        { /*sentinel*/ }
};

static struct platform_driver ocelot_reset_driver = {
        .probe = ocelot_reset_probe,
        .driver = {
                .name = "ocelot-chip-reset",
                .of_match_table = ocelot_reset_of_match,
        },
};
builtin_platform_driver(ocelot_reset_driver);