// SPDX-License-Identifier: GPL-2.0-only
/*
 * Generic NAND driver
 *
 * Author: Vitaly Wool <vitalywool@gmail.com>
 */

#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/platnand.h>

struct plat_nand_data {
        struct nand_controller  controller;
        struct nand_chip        chip;
        void __iomem            *io_base;
};

static int plat_nand_attach_chip(struct nand_chip *chip)
{
        if (chip->ecc.engine_type == NAND_ECC_ENGINE_TYPE_SOFT &&
            chip->ecc.algo == NAND_ECC_ALGO_UNKNOWN)
                chip->ecc.algo = NAND_ECC_ALGO_HAMMING;

        return 0;
}

static const struct nand_controller_ops plat_nand_ops = {
        .attach_chip = plat_nand_attach_chip,
};

/*
 * Probe for the NAND device.
 */
static int plat_nand_probe(struct platform_device *pdev)
{
        struct platform_nand_data *pdata = dev_get_platdata(&pdev->dev);
        struct plat_nand_data *data;
        struct mtd_info *mtd;
        const char **part_types;
        int err = 0;

        if (!pdata) {
                dev_err(&pdev->dev, "platform_nand_data is missing\n");
                return -EINVAL;
        }

        if (pdata->chip.nr_chips < 1) {
                dev_err(&pdev->dev, "invalid number of chips specified\n");
                return -EINVAL;
        }

        /* Allocate memory for the device structure (and zero it) */
        data = devm_kzalloc(&pdev->dev, sizeof(struct plat_nand_data),
                            GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->controller.ops = &plat_nand_ops;
        nand_controller_init(&data->controller);
        data->chip.controller = &data->controller;

        data->io_base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(data->io_base))
                return PTR_ERR(data->io_base);

        nand_set_flash_node(&data->chip, pdev->dev.of_node);
        mtd = nand_to_mtd(&data->chip);
        mtd->dev.parent = &pdev->dev;

        data->chip.legacy.IO_ADDR_R = data->io_base;
        data->chip.legacy.IO_ADDR_W = data->io_base;
        data->chip.legacy.cmd_ctrl = pdata->ctrl.cmd_ctrl;
        data->chip.legacy.dev_ready = pdata->ctrl.dev_ready;
        data->chip.legacy.select_chip = pdata->ctrl.select_chip;
        data->chip.legacy.write_buf = pdata->ctrl.write_buf;
        data->chip.legacy.read_buf = pdata->ctrl.read_buf;
        data->chip.legacy.chip_delay = pdata->chip.chip_delay;
        data->chip.options |= pdata->chip.options;
        data->chip.bbt_options |= pdata->chip.bbt_options;

        platform_set_drvdata(pdev, data);

        /* Handle any platform specific setup */
        if (pdata->ctrl.probe) {
                err = pdata->ctrl.probe(pdev);
                if (err)
                        goto out;
        }

        /*
         * This driver assumes that the default ECC engine should be TYPE_SOFT.
         * Set ->engine_type before registering the NAND devices in order to
         * provide a driver specific default value.
         */
        data->chip.ecc.engine_type = NAND_ECC_ENGINE_TYPE_SOFT;

        /* Scan to find existence of the device */
        err = nand_scan(&data->chip, pdata->chip.nr_chips);
        if (err)
                goto out;

        part_types = pdata->chip.part_probe_types;

        err = mtd_device_parse_register(mtd, part_types, NULL,
                                        pdata->chip.partitions,
                                        pdata->chip.nr_partitions);

        if (!err)
                return err;

        nand_cleanup(&data->chip);
out:
        if (pdata->ctrl.remove)
                pdata->ctrl.remove(pdev);
        return err;
}

/*
 * Remove a NAND device.
 */
static void plat_nand_remove(struct platform_device *pdev)
{
        struct plat_nand_data *data = platform_get_drvdata(pdev);
        struct platform_nand_data *pdata = dev_get_platdata(&pdev->dev);
        struct nand_chip *chip = &data->chip;
        int ret;

        ret = mtd_device_unregister(nand_to_mtd(chip));
        WARN_ON(ret);
        nand_cleanup(chip);
        if (pdata->ctrl.remove)
                pdata->ctrl.remove(pdev);
}

static const struct of_device_id plat_nand_match[] = {
        { .compatible = "gen_nand" },
        {},
};
MODULE_DEVICE_TABLE(of, plat_nand_match);

static struct platform_driver plat_nand_driver = {
        .probe  = plat_nand_probe,
        .remove = plat_nand_remove,
        .driver = {
                .name           = "gen_nand",
                .of_match_table = plat_nand_match,
        },
};

module_platform_driver(plat_nand_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Vitaly Wool");
MODULE_DESCRIPTION("Simple generic NAND driver");
MODULE_ALIAS("platform:gen_nand");