// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Copyright (C) 2004 Richard Purdie
 *  Copyright (C) 2008 Dmitry Baryshkov
 *
 *  Based on Sharp's NAND driver sharp_sl.c
 */

#include <linux/slab.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/rawnand.h>
#include <linux/mtd/partitions.h>
#include <linux/mtd/sharpsl.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/io.h>

struct sharpsl_nand {
        struct nand_controller  controller;
        struct nand_chip        chip;

        void __iomem            *io;
};

static inline struct sharpsl_nand *mtd_to_sharpsl(struct mtd_info *mtd)
{
        return container_of(mtd_to_nand(mtd), struct sharpsl_nand, chip);
}

/* register offset */
#define ECCLPLB         0x00    /* line parity 7 - 0 bit */
#define ECCLPUB         0x04    /* line parity 15 - 8 bit */
#define ECCCP           0x08    /* column parity 5 - 0 bit */
#define ECCCNTR         0x0C    /* ECC byte counter */
#define ECCCLRR         0x10    /* cleare ECC */
#define FLASHIO         0x14    /* Flash I/O */
#define FLASHCTL        0x18    /* Flash Control */

/* Flash control bit */
#define FLRYBY          (1 << 5)
#define FLCE1           (1 << 4)
#define FLWP            (1 << 3)
#define FLALE           (1 << 2)
#define FLCLE           (1 << 1)
#define FLCE0           (1 << 0)

/*
 *      hardware specific access to control-lines
 *      ctrl:
 *      NAND_CNE: bit 0 -> ! bit 0 & 4
 *      NAND_CLE: bit 1 -> bit 1
 *      NAND_ALE: bit 2 -> bit 2
 *
 */
static void sharpsl_nand_hwcontrol(struct nand_chip *chip, int cmd,
                                   unsigned int ctrl)
{
        struct sharpsl_nand *sharpsl = mtd_to_sharpsl(nand_to_mtd(chip));

        if (ctrl & NAND_CTRL_CHANGE) {
                unsigned char bits = ctrl & 0x07;

                bits |= (ctrl & 0x01) << 4;

                bits ^= 0x11;

                writeb((readb(sharpsl->io + FLASHCTL) & ~0x17) | bits, sharpsl->io + FLASHCTL);
        }

        if (cmd != NAND_CMD_NONE)
                writeb(cmd, chip->legacy.IO_ADDR_W);
}

static int sharpsl_nand_dev_ready(struct nand_chip *chip)
{
        struct sharpsl_nand *sharpsl = mtd_to_sharpsl(nand_to_mtd(chip));
        return !((readb(sharpsl->io + FLASHCTL) & FLRYBY) == 0);
}

static void sharpsl_nand_enable_hwecc(struct nand_chip *chip, int mode)
{
        struct sharpsl_nand *sharpsl = mtd_to_sharpsl(nand_to_mtd(chip));
        writeb(0, sharpsl->io + ECCCLRR);
}

static int sharpsl_nand_calculate_ecc(struct nand_chip *chip,
                                      const u_char * dat, u_char * ecc_code)
{
        struct sharpsl_nand *sharpsl = mtd_to_sharpsl(nand_to_mtd(chip));
        ecc_code[0] = ~readb(sharpsl->io + ECCLPUB);
        ecc_code[1] = ~readb(sharpsl->io + ECCLPLB);
        ecc_code[2] = (~readb(sharpsl->io + ECCCP) << 2) | 0x03;
        return readb(sharpsl->io + ECCCNTR) != 0;
}

static int sharpsl_attach_chip(struct nand_chip *chip)
{
        if (chip->ecc.engine_type != NAND_ECC_ENGINE_TYPE_ON_HOST)
                return 0;

        chip->ecc.size = 256;
        chip->ecc.bytes = 3;
        chip->ecc.strength = 1;
        chip->ecc.hwctl = sharpsl_nand_enable_hwecc;
        chip->ecc.calculate = sharpsl_nand_calculate_ecc;
        chip->ecc.correct = rawnand_sw_hamming_correct;

        return 0;
}

static const struct nand_controller_ops sharpsl_ops = {
        .attach_chip = sharpsl_attach_chip,
};

/*
 * Main initialization routine
 */
static int sharpsl_nand_probe(struct platform_device *pdev)
{
        struct nand_chip *this;
        struct mtd_info *mtd;
        struct resource *r;
        int err = 0;
        struct sharpsl_nand *sharpsl;
        struct sharpsl_nand_platform_data *data = dev_get_platdata(&pdev->dev);

        if (!data) {
                dev_err(&pdev->dev, "no platform data!\n");
                return -EINVAL;
        }

        /* Allocate memory for MTD device structure and private data */
        sharpsl = kzalloc_obj(struct sharpsl_nand);
        if (!sharpsl)
                return -ENOMEM;

        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!r) {
                dev_err(&pdev->dev, "no io memory resource defined!\n");
                err = -ENODEV;
                goto err_get_res;
        }

        /* map physical address */
        sharpsl->io = ioremap(r->start, resource_size(r));
        if (!sharpsl->io) {
                dev_err(&pdev->dev, "ioremap to access Sharp SL NAND chip failed\n");
                err = -EIO;
                goto err_ioremap;
        }

        /* Get pointer to private data */
        this = (struct nand_chip *)(&sharpsl->chip);

        nand_controller_init(&sharpsl->controller);
        sharpsl->controller.ops = &sharpsl_ops;
        this->controller = &sharpsl->controller;

        /* Link the private data with the MTD structure */
        mtd = nand_to_mtd(this);
        mtd->dev.parent = &pdev->dev;
        mtd_set_ooblayout(mtd, data->ecc_layout);

        platform_set_drvdata(pdev, sharpsl);

        /*
         * PXA initialize
         */
        writeb(readb(sharpsl->io + FLASHCTL) | FLWP, sharpsl->io + FLASHCTL);

        /* Set address of NAND IO lines */
        this->legacy.IO_ADDR_R = sharpsl->io + FLASHIO;
        this->legacy.IO_ADDR_W = sharpsl->io + FLASHIO;
        /* Set address of hardware control function */
        this->legacy.cmd_ctrl = sharpsl_nand_hwcontrol;
        this->legacy.dev_ready = sharpsl_nand_dev_ready;
        /* 15 us command delay time */
        this->legacy.chip_delay = 15;
        this->badblock_pattern = data->badblock_pattern;

        /* Scan to find existence of the device */
        err = nand_scan(this, 1);
        if (err)
                goto err_scan;

        /* Register the partitions */
        mtd->name = "sharpsl-nand";

        err = mtd_device_parse_register(mtd, data->part_parsers, NULL,
                                        data->partitions, data->nr_partitions);
        if (err)
                goto err_add;

        /* Return happy */
        return 0;

err_add:
        nand_cleanup(this);

err_scan:
        iounmap(sharpsl->io);
err_ioremap:
err_get_res:
        kfree(sharpsl);
        return err;
}

/*
 * Clean up routine
 */
static void sharpsl_nand_remove(struct platform_device *pdev)
{
        struct sharpsl_nand *sharpsl = platform_get_drvdata(pdev);
        struct nand_chip *chip = &sharpsl->chip;
        int ret;

        /* Unregister device */
        ret = mtd_device_unregister(nand_to_mtd(chip));
        WARN_ON(ret);

        /* Release resources */
        nand_cleanup(chip);

        iounmap(sharpsl->io);

        /* Free the driver's structure */
        kfree(sharpsl);
}

static struct platform_driver sharpsl_nand_driver = {
        .driver = {
                .name   = "sharpsl-nand",
        },
        .probe          = sharpsl_nand_probe,
        .remove         = sharpsl_nand_remove,
};

module_platform_driver(sharpsl_nand_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
MODULE_DESCRIPTION("Device specific logic for NAND flash on Sharp SL-C7xx Series");