// SPDX-License-Identifier: GPL-2.0
/*
 * Author: Mario Kicherer <dev@kicherer.org>
 */

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

#define SPINAND_MFR_ALLIANCEMEMORY      0x52

#define AM_STATUS_ECC_BITMASK           (3 << 4)

#define AM_STATUS_ECC_NONE_DETECTED     (0 << 4)
#define AM_STATUS_ECC_CORRECTED         (1 << 4)
#define AM_STATUS_ECC_ERRORED           (2 << 4)
#define AM_STATUS_ECC_MAX_CORRECTED     (3 << 4)

static SPINAND_OP_VARIANTS(read_cache_variants,
                SPINAND_PAGE_READ_FROM_CACHE_1S_4S_4S_OP(0, 1, NULL, 0, 0),
                SPINAND_PAGE_READ_FROM_CACHE_1S_1S_4S_OP(0, 1, NULL, 0, 0),
                SPINAND_PAGE_READ_FROM_CACHE_1S_2S_2S_OP(0, 1, NULL, 0, 0),
                SPINAND_PAGE_READ_FROM_CACHE_1S_1S_2S_OP(0, 1, NULL, 0, 0),
                SPINAND_PAGE_READ_FROM_CACHE_FAST_1S_1S_1S_OP(0, 1, NULL, 0, 0),
                SPINAND_PAGE_READ_FROM_CACHE_1S_1S_1S_OP(0, 1, NULL, 0, 0));

static SPINAND_OP_VARIANTS(write_cache_variants,
                           SPINAND_PROG_LOAD_1S_1S_4S_OP(true, 0, NULL, 0),
                           SPINAND_PROG_LOAD_1S_1S_1S_OP(true, 0, NULL, 0));

static SPINAND_OP_VARIANTS(update_cache_variants,
                           SPINAND_PROG_LOAD_1S_1S_4S_OP(false, 0, NULL, 0),
                           SPINAND_PROG_LOAD_1S_1S_1S_OP(false, 0, NULL, 0));

static int am_get_eccsize(struct mtd_info *mtd)
{
        if (mtd->oobsize == 64)
                return 0x20;
        else if (mtd->oobsize == 128)
                return 0x38;
        else if (mtd->oobsize == 256)
                return 0x70;
        else
                return -EINVAL;
}

static int am_ooblayout_ecc(struct mtd_info *mtd, int section,
                            struct mtd_oob_region *region)
{
        int ecc_bytes;

        ecc_bytes = am_get_eccsize(mtd);
        if (ecc_bytes < 0)
                return ecc_bytes;

        region->offset = mtd->oobsize - ecc_bytes;
        region->length = ecc_bytes;

        return 0;
}

static int am_ooblayout_free(struct mtd_info *mtd, int section,
                             struct mtd_oob_region *region)
{
        int ecc_bytes;

        if (section)
                return -ERANGE;

        ecc_bytes = am_get_eccsize(mtd);
        if (ecc_bytes < 0)
                return ecc_bytes;

        /*
         * It is unclear how many bytes are used for the bad block marker. We
         * reserve the common two bytes here.
         *
         * The free area in this kind of flash is divided into chunks where the
         * first 4 bytes of each chunk are unprotected. The number of chunks
         * depends on the specific model. The models with 4096+256 bytes pages
         * have 8 chunks, the others 4 chunks.
         */

        region->offset = 2;
        region->length = mtd->oobsize - 2 - ecc_bytes;

        return 0;
}

static const struct mtd_ooblayout_ops am_ooblayout = {
        .ecc = am_ooblayout_ecc,
        .free = am_ooblayout_free,
};

static int am_ecc_get_status(struct spinand_device *spinand, u8 status)
{
        switch (status & AM_STATUS_ECC_BITMASK) {
        case AM_STATUS_ECC_NONE_DETECTED:
                return 0;

        case AM_STATUS_ECC_CORRECTED:
                /*
                 * use oobsize to determine the flash model and the maximum of
                 * correctable errors and return maximum - 1 by convention
                 */
                if (spinand->base.mtd.oobsize == 64)
                        return 3;
                else
                        return 7;

        case AM_STATUS_ECC_ERRORED:
                return -EBADMSG;

        case AM_STATUS_ECC_MAX_CORRECTED:
                /*
                 * use oobsize to determine the flash model and the maximum of
                 * correctable errors
                 */
                if (spinand->base.mtd.oobsize == 64)
                        return 4;
                else
                        return 8;

        default:
                break;
        }

        return -EINVAL;
}

static const struct spinand_info alliancememory_spinand_table[] = {
        SPINAND_INFO("AS5F34G04SND",
                     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_DUMMY, 0x2f),
                     NAND_MEMORG(1, 2048, 128, 64, 4096, 80, 1, 1, 1),
                     NAND_ECCREQ(4, 512),
                     SPINAND_INFO_OP_VARIANTS(&read_cache_variants,
                                              &write_cache_variants,
                                              &update_cache_variants),
                     SPINAND_HAS_QE_BIT,
                     SPINAND_ECCINFO(&am_ooblayout,
                                     am_ecc_get_status)),
};

static const struct spinand_manufacturer_ops alliancememory_spinand_manuf_ops = {
};

const struct spinand_manufacturer alliancememory_spinand_manufacturer = {
        .id = SPINAND_MFR_ALLIANCEMEMORY,
        .name = "AllianceMemory",
        .chips = alliancememory_spinand_table,
        .nchips = ARRAY_SIZE(alliancememory_spinand_table),
        .ops = &alliancememory_spinand_manuf_ops,
};