// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2025, SaluteDevices. All Rights Reserved.
 *
 * Author: Martin Kurbanov <mmkurbanov@salutedevices.com>
 */

#include <linux/mtd/mtd.h>
#include <linux/mtd/spinand.h>

/**
 * spinand_otp_page_size() - Get SPI-NAND OTP page size
 * @spinand: the spinand device
 *
 * Return: the OTP page size.
 */
size_t spinand_otp_page_size(struct spinand_device *spinand)
{
        struct nand_device *nand = spinand_to_nand(spinand);

        return nanddev_page_size(nand) + nanddev_per_page_oobsize(nand);
}

static size_t spinand_otp_size(struct spinand_device *spinand,
                               const struct spinand_otp_layout *layout)
{
        return layout->npages * spinand_otp_page_size(spinand);
}

/**
 * spinand_fact_otp_size() - Get SPI-NAND factory OTP area size
 * @spinand: the spinand device
 *
 * Return: the OTP size.
 */
size_t spinand_fact_otp_size(struct spinand_device *spinand)
{
        return spinand_otp_size(spinand, &spinand->fact_otp->layout);
}

/**
 * spinand_user_otp_size() - Get SPI-NAND user OTP area size
 * @spinand: the spinand device
 *
 * Return: the OTP size.
 */
size_t spinand_user_otp_size(struct spinand_device *spinand)
{
        return spinand_otp_size(spinand, &spinand->user_otp->layout);
}

static int spinand_otp_check_bounds(struct spinand_device *spinand, loff_t ofs,
                                    size_t len,
                                    const struct spinand_otp_layout *layout)
{
        if (ofs < 0 || ofs + len > spinand_otp_size(spinand, layout))
                return -EINVAL;

        return 0;
}

static int spinand_user_otp_check_bounds(struct spinand_device *spinand,
                                         loff_t ofs, size_t len)
{
        return spinand_otp_check_bounds(spinand, ofs, len,
                                        &spinand->user_otp->layout);
}

static int spinand_otp_rw(struct spinand_device *spinand, loff_t ofs,
                          size_t len, size_t *retlen, u8 *buf, bool is_write,
                          const struct spinand_otp_layout *layout)
{
        struct nand_page_io_req req = {};
        unsigned long long page;
        size_t copied = 0;
        size_t otp_pagesize = spinand_otp_page_size(spinand);
        int ret;

        if (!len)
                return 0;

        ret = spinand_otp_check_bounds(spinand, ofs, len, layout);
        if (ret)
                return ret;

        ret = spinand_upd_cfg(spinand, CFG_OTP_ENABLE, CFG_OTP_ENABLE);
        if (ret)
                return ret;

        page = ofs;
        req.dataoffs = do_div(page, otp_pagesize);
        req.pos.page = page + layout->start_page;
        req.type = is_write ? NAND_PAGE_WRITE : NAND_PAGE_READ;
        req.mode = MTD_OPS_RAW;
        req.databuf.in = buf;

        while (copied < len) {
                req.datalen = min_t(unsigned int,
                                    otp_pagesize - req.dataoffs,
                                    len - copied);

                if (is_write)
                        ret = spinand_write_page(spinand, &req);
                else
                        ret = spinand_read_page(spinand, &req);

                if (ret < 0)
                        break;

                req.databuf.in += req.datalen;
                req.pos.page++;
                req.dataoffs = 0;
                copied += req.datalen;
        }

        *retlen = copied;

        if (spinand_upd_cfg(spinand, CFG_OTP_ENABLE, 0)) {
                dev_warn(&spinand_to_mtd(spinand)->dev,
                         "Can not disable OTP mode\n");
                ret = -EIO;
        }

        return ret;
}

/**
 * spinand_fact_otp_read() - Read from OTP area
 * @spinand: the spinand device
 * @ofs: the offset to read
 * @len: the number of data bytes to read
 * @retlen: the pointer to variable to store the number of read bytes
 * @buf: the buffer to store the read data
 *
 * Return: 0 on success, an error code otherwise.
 */
int spinand_fact_otp_read(struct spinand_device *spinand, loff_t ofs,
                          size_t len, size_t *retlen, u8 *buf)
{
        return spinand_otp_rw(spinand, ofs, len, retlen, buf, false,
                              &spinand->fact_otp->layout);
}

/**
 * spinand_user_otp_read() - Read from OTP area
 * @spinand: the spinand device
 * @ofs: the offset to read
 * @len: the number of data bytes to read
 * @retlen: the pointer to variable to store the number of read bytes
 * @buf: the buffer to store the read data
 *
 * Return: 0 on success, an error code otherwise.
 */
int spinand_user_otp_read(struct spinand_device *spinand, loff_t ofs,
                          size_t len, size_t *retlen, u8 *buf)
{
        return spinand_otp_rw(spinand, ofs, len, retlen, buf, false,
                              &spinand->user_otp->layout);
}

/**
 * spinand_user_otp_write() - Write to OTP area
 * @spinand:  the spinand device
 * @ofs: the offset to write to
 * @len: the number of bytes to write
 * @retlen: the pointer to variable to store the number of written bytes
 * @buf: the buffer with data to write
 *
 * Return: 0 on success, an error code otherwise.
 */
int spinand_user_otp_write(struct spinand_device *spinand, loff_t ofs,
                           size_t len, size_t *retlen, const u8 *buf)
{
        return spinand_otp_rw(spinand, ofs, len, retlen, (u8 *)buf, true,
                              &spinand->user_otp->layout);
}

static int spinand_mtd_otp_info(struct mtd_info *mtd, size_t len,
                                size_t *retlen, struct otp_info *buf,
                                bool is_fact)
{
        struct spinand_device *spinand = mtd_to_spinand(mtd);
        int ret;

        *retlen = 0;

        mutex_lock(&spinand->lock);

        if (is_fact)
                ret = spinand->fact_otp->ops->info(spinand, len, buf, retlen);
        else
                ret = spinand->user_otp->ops->info(spinand, len, buf, retlen);

        mutex_unlock(&spinand->lock);

        return ret;
}

static int spinand_mtd_fact_otp_info(struct mtd_info *mtd, size_t len,
                                     size_t *retlen, struct otp_info *buf)
{
        return spinand_mtd_otp_info(mtd, len, retlen, buf, true);
}

static int spinand_mtd_user_otp_info(struct mtd_info *mtd, size_t len,
                                     size_t *retlen, struct otp_info *buf)
{
        return spinand_mtd_otp_info(mtd, len, retlen, buf, false);
}

static int spinand_mtd_otp_read(struct mtd_info *mtd, loff_t ofs, size_t len,
                                size_t *retlen, u8 *buf, bool is_fact)
{
        struct spinand_device *spinand = mtd_to_spinand(mtd);
        int ret;

        *retlen = 0;

        if (!len)
                return 0;

        ret = spinand_otp_check_bounds(spinand, ofs, len,
                                       is_fact ? &spinand->fact_otp->layout :
                                                 &spinand->user_otp->layout);
        if (ret)
                return ret;

        mutex_lock(&spinand->lock);

        if (is_fact)
                ret = spinand->fact_otp->ops->read(spinand, ofs, len, retlen,
                                                   buf);
        else
                ret = spinand->user_otp->ops->read(spinand, ofs, len, retlen,
                                                   buf);

        mutex_unlock(&spinand->lock);

        return ret;
}

static int spinand_mtd_fact_otp_read(struct mtd_info *mtd, loff_t ofs,
                                     size_t len, size_t *retlen, u8 *buf)
{
        return spinand_mtd_otp_read(mtd, ofs, len, retlen, buf, true);
}

static int spinand_mtd_user_otp_read(struct mtd_info *mtd, loff_t ofs,
                                     size_t len, size_t *retlen, u8 *buf)
{
        return spinand_mtd_otp_read(mtd, ofs, len, retlen, buf, false);
}

static int spinand_mtd_user_otp_write(struct mtd_info *mtd, loff_t ofs,
                                      size_t len, size_t *retlen, const u8 *buf)
{
        struct spinand_device *spinand = mtd_to_spinand(mtd);
        const struct spinand_user_otp_ops *ops = spinand->user_otp->ops;
        int ret;

        *retlen = 0;

        if (!len)
                return 0;

        ret = spinand_user_otp_check_bounds(spinand, ofs, len);
        if (ret)
                return ret;

        mutex_lock(&spinand->lock);
        ret = ops->write(spinand, ofs, len, retlen, buf);
        mutex_unlock(&spinand->lock);

        return ret;
}

static int spinand_mtd_user_otp_erase(struct mtd_info *mtd, loff_t ofs,
                                      size_t len)
{
        struct spinand_device *spinand = mtd_to_spinand(mtd);
        const struct spinand_user_otp_ops *ops = spinand->user_otp->ops;
        int ret;

        if (!len)
                return 0;

        ret = spinand_user_otp_check_bounds(spinand, ofs, len);
        if (ret)
                return ret;

        mutex_lock(&spinand->lock);
        ret = ops->erase(spinand, ofs, len);
        mutex_unlock(&spinand->lock);

        return ret;
}

static int spinand_mtd_user_otp_lock(struct mtd_info *mtd, loff_t ofs,
                                     size_t len)
{
        struct spinand_device *spinand = mtd_to_spinand(mtd);
        const struct spinand_user_otp_ops *ops = spinand->user_otp->ops;
        int ret;

        if (!len)
                return 0;

        ret = spinand_user_otp_check_bounds(spinand, ofs, len);
        if (ret)
                return ret;

        mutex_lock(&spinand->lock);
        ret = ops->lock(spinand, ofs, len);
        mutex_unlock(&spinand->lock);

        return ret;
}

/**
 * spinand_set_mtd_otp_ops() - Setup OTP methods
 * @spinand: the spinand device
 *
 * Setup OTP methods.
 *
 * Return: 0 on success, a negative error code otherwise.
 */
int spinand_set_mtd_otp_ops(struct spinand_device *spinand)
{
        struct mtd_info *mtd = spinand_to_mtd(spinand);
        const struct spinand_fact_otp_ops *fact_ops = spinand->fact_otp->ops;
        const struct spinand_user_otp_ops *user_ops = spinand->user_otp->ops;

        if (!user_ops && !fact_ops)
                return -EINVAL;

        if (user_ops) {
                if (user_ops->info)
                        mtd->_get_user_prot_info = spinand_mtd_user_otp_info;

                if (user_ops->read)
                        mtd->_read_user_prot_reg = spinand_mtd_user_otp_read;

                if (user_ops->write)
                        mtd->_write_user_prot_reg = spinand_mtd_user_otp_write;

                if (user_ops->lock)
                        mtd->_lock_user_prot_reg = spinand_mtd_user_otp_lock;

                if (user_ops->erase)
                        mtd->_erase_user_prot_reg = spinand_mtd_user_otp_erase;
        }

        if (fact_ops) {
                if (fact_ops->info)
                        mtd->_get_fact_prot_info = spinand_mtd_fact_otp_info;

                if (fact_ops->read)
                        mtd->_read_fact_prot_reg = spinand_mtd_fact_otp_read;
        }

        return 0;
}