// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Versatile OF physmap driver add-on
 *
 * Copyright (c) 2016, Linaro Limited
 * Author: Linus Walleij <linus.walleij@linaro.org>
 */
#include <linux/export.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/mtd/map.h>
#include <linux/mfd/syscon.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/bitops.h>
#include "physmap-versatile.h"

static struct regmap *syscon_regmap;

enum versatile_flashprot {
        INTEGRATOR_AP_FLASHPROT,
        INTEGRATOR_CP_FLASHPROT,
        VERSATILE_FLASHPROT,
        REALVIEW_FLASHPROT,
};

static const struct of_device_id syscon_match[] = {
        {
                .compatible = "arm,integrator-ap-syscon",
                .data = (void *)INTEGRATOR_AP_FLASHPROT,
        },
        {
                .compatible = "arm,integrator-cp-syscon",
                .data = (void *)INTEGRATOR_CP_FLASHPROT,
        },
        {
                .compatible = "arm,core-module-versatile",
                .data = (void *)VERSATILE_FLASHPROT,
        },
        {
                .compatible = "arm,realview-eb-syscon",
                .data = (void *)REALVIEW_FLASHPROT,
        },
        {
                .compatible = "arm,realview-pb1176-syscon",
                .data = (void *)REALVIEW_FLASHPROT,
        },
        {
                .compatible = "arm,realview-pb11mp-syscon",
                .data = (void *)REALVIEW_FLASHPROT,
        },
        {
                .compatible = "arm,realview-pba8-syscon",
                .data = (void *)REALVIEW_FLASHPROT,
        },
        {
                .compatible = "arm,realview-pbx-syscon",
                .data = (void *)REALVIEW_FLASHPROT,
        },
        {},
};

/*
 * Flash protection handling for the Integrator/AP
 */
#define INTEGRATOR_SC_CTRLS_OFFSET      0x08
#define INTEGRATOR_SC_CTRLC_OFFSET      0x0C
#define INTEGRATOR_SC_CTRL_FLVPPEN      BIT(1)
#define INTEGRATOR_SC_CTRL_FLWP         BIT(2)

#define INTEGRATOR_EBI_CSR1_OFFSET      0x04
/* The manual says bit 2, the code says bit 3, trust the code */
#define INTEGRATOR_EBI_WRITE_ENABLE     BIT(3)
#define INTEGRATOR_EBI_LOCK_OFFSET      0x20
#define INTEGRATOR_EBI_LOCK_VAL         0xA05F

static const struct of_device_id ebi_match[] = {
        { .compatible = "arm,external-bus-interface"},
        { },
};

static int ap_flash_init(struct platform_device *pdev)
{
        struct device_node *ebi;
        void __iomem *ebi_base;
        u32 val;
        int ret;

        /* Look up the EBI */
        ebi = of_find_matching_node(NULL, ebi_match);
        if (!ebi) {
                return -ENODEV;
        }
        ebi_base = of_iomap(ebi, 0);
        of_node_put(ebi);
        if (!ebi_base)
                return -ENODEV;

        /* Clear VPP and write protection bits */
        ret = regmap_write(syscon_regmap,
                INTEGRATOR_SC_CTRLC_OFFSET,
                INTEGRATOR_SC_CTRL_FLVPPEN | INTEGRATOR_SC_CTRL_FLWP);
        if (ret)
                dev_err(&pdev->dev, "error clearing Integrator VPP/WP\n");

        /* Unlock the EBI */
        writel(INTEGRATOR_EBI_LOCK_VAL, ebi_base + INTEGRATOR_EBI_LOCK_OFFSET);

        /* Enable write cycles on the EBI, CSR1 (flash) */
        val = readl(ebi_base + INTEGRATOR_EBI_CSR1_OFFSET);
        val |= INTEGRATOR_EBI_WRITE_ENABLE;
        writel(val, ebi_base + INTEGRATOR_EBI_CSR1_OFFSET);

        /* Lock the EBI again */
        writel(0, ebi_base + INTEGRATOR_EBI_LOCK_OFFSET);
        iounmap(ebi_base);

        return 0;
}

static void ap_flash_set_vpp(struct map_info *map, int on)
{
        int ret;

        if (on) {
                ret = regmap_write(syscon_regmap,
                        INTEGRATOR_SC_CTRLS_OFFSET,
                        INTEGRATOR_SC_CTRL_FLVPPEN | INTEGRATOR_SC_CTRL_FLWP);
                if (ret)
                        pr_err("error enabling AP VPP\n");
        } else {
                ret = regmap_write(syscon_regmap,
                        INTEGRATOR_SC_CTRLC_OFFSET,
                        INTEGRATOR_SC_CTRL_FLVPPEN | INTEGRATOR_SC_CTRL_FLWP);
                if (ret)
                        pr_err("error disabling AP VPP\n");
        }
}

/*
 * Flash protection handling for the Integrator/CP
 */

#define INTCP_FLASHPROG_OFFSET          0x04
#define CINTEGRATOR_FLVPPEN             BIT(0)
#define CINTEGRATOR_FLWREN              BIT(1)
#define CINTEGRATOR_FLMASK              BIT(0)|BIT(1)

static void cp_flash_set_vpp(struct map_info *map, int on)
{
        int ret;

        if (on) {
                ret = regmap_update_bits(syscon_regmap,
                                INTCP_FLASHPROG_OFFSET,
                                CINTEGRATOR_FLMASK,
                                CINTEGRATOR_FLVPPEN | CINTEGRATOR_FLWREN);
                if (ret)
                        pr_err("error setting CP VPP\n");
        } else {
                ret = regmap_update_bits(syscon_regmap,
                                INTCP_FLASHPROG_OFFSET,
                                CINTEGRATOR_FLMASK,
                                0);
                if (ret)
                        pr_err("error setting CP VPP\n");
        }
}

/*
 * Flash protection handling for the Versatiles and RealViews
 */

#define VERSATILE_SYS_FLASH_OFFSET            0x4C

static void versatile_flash_set_vpp(struct map_info *map, int on)
{
        int ret;

        ret = regmap_update_bits(syscon_regmap, VERSATILE_SYS_FLASH_OFFSET,
                                 0x01, !!on);
        if (ret)
                pr_err("error setting Versatile VPP\n");
}

int of_flash_probe_versatile(struct platform_device *pdev,
                             struct device_node *np,
                             struct map_info *map)
{
        struct device_node *sysnp;
        const struct of_device_id *devid;
        struct regmap *rmap;
        static enum versatile_flashprot versatile_flashprot;
        int ret;

        /* Not all flash chips use this protection line */
        if (!of_device_is_compatible(np, "arm,versatile-flash"))
                return 0;

        /* For first chip probed, look up the syscon regmap */
        if (!syscon_regmap) {
                sysnp = of_find_matching_node_and_match(NULL,
                                                        syscon_match,
                                                        &devid);
                if (!sysnp)
                        return -ENODEV;

                versatile_flashprot = (uintptr_t)devid->data;
                rmap = syscon_node_to_regmap(sysnp);
                of_node_put(sysnp);
                if (IS_ERR(rmap))
                        return PTR_ERR(rmap);

                syscon_regmap = rmap;
        }

        switch (versatile_flashprot) {
        case INTEGRATOR_AP_FLASHPROT:
                ret = ap_flash_init(pdev);
                if (ret)
                        return ret;
                map->set_vpp = ap_flash_set_vpp;
                dev_info(&pdev->dev, "Integrator/AP flash protection\n");
                break;
        case INTEGRATOR_CP_FLASHPROT:
                map->set_vpp = cp_flash_set_vpp;
                dev_info(&pdev->dev, "Integrator/CP flash protection\n");
                break;
        case VERSATILE_FLASHPROT:
        case REALVIEW_FLASHPROT:
                map->set_vpp = versatile_flash_set_vpp;
                dev_info(&pdev->dev, "versatile/realview flash protection\n");
                break;
        default:
                dev_info(&pdev->dev, "device marked as Versatile flash "
                         "but no system controller was found\n");
                break;
        }

        return 0;
}