linux/drivers/mtd/nand/ecc-sw-bch.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * This file provides ECC correction for more than 1 bit per block of data,
 * using binary BCH codes. It relies on the generic BCH library lib/bch.c.
 *
 * Copyright © 2011 Ivan Djelic <[email protected]>
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/bitops.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/nand-ecc-sw-bch.h>

/**
 * nand_ecc_sw_bch_calculate - Calculate the ECC corresponding to a data block
 * @nand: NAND device
 * @buf: Input buffer with raw data
 * @code: Output buffer with ECC
 */
int nand_ecc_sw_bch_calculate(struct nand_device *nand,
			      const unsigned char *buf, unsigned char *code)
{ … }
EXPORT_SYMBOL(…);

/**
 * nand_ecc_sw_bch_correct - Detect, correct and report bit error(s)
 * @nand: NAND device
 * @buf: Raw data read from the chip
 * @read_ecc: ECC bytes from the chip
 * @calc_ecc: ECC calculated from the raw data
 *
 * Detect and correct bit errors for a data block.
 */
int nand_ecc_sw_bch_correct(struct nand_device *nand, unsigned char *buf,
			    unsigned char *read_ecc, unsigned char *calc_ecc)
{ … }
EXPORT_SYMBOL(…);

/**
 * nand_ecc_sw_bch_cleanup - Cleanup software BCH ECC resources
 * @nand: NAND device
 */
static void nand_ecc_sw_bch_cleanup(struct nand_device *nand)
{ … }

/**
 * nand_ecc_sw_bch_init - Initialize software BCH ECC engine
 * @nand: NAND device
 *
 * Returns: a pointer to a new NAND BCH control structure, or NULL upon failure
 *
 * Initialize NAND BCH error correction. @nand.ecc parameters 'step_size' and
 * 'bytes' are used to compute the following BCH parameters:
 *     m, the Galois field order
 *     t, the error correction capability
 * 'bytes' should be equal to the number of bytes required to store m * t
 * bits, where m is such that 2^m - 1 > step_size * 8.
 *
 * Example: to configure 4 bit correction per 512 bytes, you should pass
 * step_size = 512 (thus, m = 13 is the smallest integer such that 2^m - 1 > 512 * 8)
 * bytes = 7 (7 bytes are required to store m * t = 13 * 4 = 52 bits)
 */
static int nand_ecc_sw_bch_init(struct nand_device *nand)
{ … }

int nand_ecc_sw_bch_init_ctx(struct nand_device *nand)
{ … }
EXPORT_SYMBOL(…);

void nand_ecc_sw_bch_cleanup_ctx(struct nand_device *nand)
{ … }
EXPORT_SYMBOL(…);

static int nand_ecc_sw_bch_prepare_io_req(struct nand_device *nand,
					  struct nand_page_io_req *req)
{ … }

static int nand_ecc_sw_bch_finish_io_req(struct nand_device *nand,
					 struct nand_page_io_req *req)
{ … }

static struct nand_ecc_engine_ops nand_ecc_sw_bch_engine_ops = …;

static struct nand_ecc_engine nand_ecc_sw_bch_engine = …;

struct nand_ecc_engine *nand_ecc_sw_bch_get_engine(void)
{ … }
EXPORT_SYMBOL(…);

MODULE_LICENSE(…) …;
MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;