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	[backport from linux commit 02f8c6aee8df3cdc935e9bdd4f2d020306035dbe] This patch merges the BCH ECC algorithm from the 3.0 Linux kernel. This enables U-Boot to support modern NAND flash chips that require more than 1-bit of ECC in software. Signed-off-by: Christian Hitz <christian.hitz@aizo.com> Cc: Scott Wood <scottwood@freescale.com> Signed-off-by: Scott Wood <scottwood@freescale.com>
		
			
				
	
	
		
			80 lines
		
	
	
		
			2.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			80 lines
		
	
	
		
			2.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * Generic binary BCH encoding/decoding library
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 *
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 * This program is free software; you can redistribute it and/or modify it
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 * under the terms of the GNU General Public License version 2 as published by
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 * the Free Software Foundation.
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 *
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 * This program is distributed in the hope that it will be useful, but WITHOUT
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
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 * more details.
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 *
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 * You should have received a copy of the GNU General Public License along with
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 * this program; if not, write to the Free Software Foundation, Inc., 51
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 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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 *
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 * Copyright © 2011 Parrot S.A.
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 *
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 * Author: Ivan Djelic <ivan.djelic@parrot.com>
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 *
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 * Description:
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 *
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 * This library provides runtime configurable encoding/decoding of binary
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 * Bose-Chaudhuri-Hocquenghem (BCH) codes.
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*/
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#ifndef _BCH_H
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#define _BCH_H
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#include <linux/types.h>
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/**
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 * struct bch_control - BCH control structure
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 * @m:          Galois field order
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 * @n:          maximum codeword size in bits (= 2^m-1)
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 * @t:          error correction capability in bits
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 * @ecc_bits:   ecc exact size in bits, i.e. generator polynomial degree (<=m*t)
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 * @ecc_bytes:  ecc max size (m*t bits) in bytes
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 * @a_pow_tab:  Galois field GF(2^m) exponentiation lookup table
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 * @a_log_tab:  Galois field GF(2^m) log lookup table
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 * @mod8_tab:   remainder generator polynomial lookup tables
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 * @ecc_buf:    ecc parity words buffer
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 * @ecc_buf2:   ecc parity words buffer
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 * @xi_tab:     GF(2^m) base for solving degree 2 polynomial roots
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 * @syn:        syndrome buffer
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 * @cache:      log-based polynomial representation buffer
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 * @elp:        error locator polynomial
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 * @poly_2t:    temporary polynomials of degree 2t
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 */
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struct bch_control {
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	unsigned int    m;
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	unsigned int    n;
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	unsigned int    t;
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	unsigned int    ecc_bits;
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	unsigned int    ecc_bytes;
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/* private: */
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	uint16_t       *a_pow_tab;
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	uint16_t       *a_log_tab;
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	uint32_t       *mod8_tab;
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	uint32_t       *ecc_buf;
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	uint32_t       *ecc_buf2;
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	unsigned int   *xi_tab;
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	unsigned int   *syn;
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	int            *cache;
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	struct gf_poly *elp;
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	struct gf_poly *poly_2t[4];
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};
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struct bch_control *init_bch(int m, int t, unsigned int prim_poly);
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void free_bch(struct bch_control *bch);
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void encode_bch(struct bch_control *bch, const uint8_t *data,
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		unsigned int len, uint8_t *ecc);
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int decode_bch(struct bch_control *bch, const uint8_t *data, unsigned int len,
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	       const uint8_t *recv_ecc, const uint8_t *calc_ecc,
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	       const unsigned int *syn, unsigned int *errloc);
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#endif /* _BCH_H */
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