// 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_QUADIO_OP(0, 1, NULL, 0),
		SPINAND_PAGE_READ_FROM_CACHE_X4_OP(0, 1, NULL, 0),
		SPINAND_PAGE_READ_FROM_CACHE_DUALIO_OP(0, 1, NULL, 0),
		SPINAND_PAGE_READ_FROM_CACHE_X2_OP(0, 1, NULL, 0),
		SPINAND_PAGE_READ_FROM_CACHE_OP(true, 0, 1, NULL, 0),
		SPINAND_PAGE_READ_FROM_CACHE_OP(false, 0, 1, NULL, 0));

static SPINAND_OP_VARIANTS(write_cache_variants,
			   SPINAND_PROG_LOAD_X4(true, 0, NULL, 0),
			   SPINAND_PROG_LOAD(true, 0, NULL, 0));

static SPINAND_OP_VARIANTS(update_cache_variants,
			   SPINAND_PROG_LOAD_X4(false, 0, NULL, 0),
			   SPINAND_PROG_LOAD(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,
};