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Diffstat (limited to 'utils/rk27utils/nandextract/libbch.h')
| -rw-r--r-- | utils/rk27utils/nandextract/libbch.h | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/utils/rk27utils/nandextract/libbch.h b/utils/rk27utils/nandextract/libbch.h new file mode 100644 index 0000000000..b4c779e815 --- /dev/null +++ b/utils/rk27utils/nandextract/libbch.h @@ -0,0 +1,113 @@ +/* + * Generic binary BCH encoding/decoding library + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., 51 + * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Copyright © 2011 Parrot S.A. + * + * Author: Ivan Djelic <ivan.djelic@parrot.com> + * + * Description: + * + * This library provides runtime configurable encoding/decoding of binary + * Bose-Chaudhuri-Hocquenghem (BCH) codes. +*/ +#ifndef _BCH_H +#define _BCH_H + +#include <stdint.h> + +#if defined(CONFIG_BCH_CONST_PARAMS) +#define GF_M(_p) (CONFIG_BCH_CONST_M) +#define GF_T(_p) (CONFIG_BCH_CONST_T) +#define GF_N(_p) ((1 << (CONFIG_BCH_CONST_M))-1) +#else +#define GF_M(_p) ((_p)->m) +#define GF_T(_p) ((_p)->t) +#define GF_N(_p) ((_p)->n) +#endif + +#define BCH_ECC_WORDS(_p) DIV_ROUND_UP(GF_M(_p)*GF_T(_p), 32) +#define BCH_ECC_BYTES(_p) DIV_ROUND_UP(GF_M(_p)*GF_T(_p), 8) + +#ifndef dbg +#define dbg(_fmt, args...) do {} while (0) +#endif + +/* + * represent a polynomial over GF(2^m) + */ +struct gf_poly { + unsigned int deg; /* polynomial degree */ + unsigned int c[0]; /* polynomial terms */ +}; + +/* given its degree, compute a polynomial size in bytes */ +#define GF_POLY_SZ(_d) (sizeof(struct gf_poly)+((_d)+1)*sizeof(unsigned int)) + +/* polynomial of degree 1 */ +struct gf_poly_deg1 { + struct gf_poly poly; + unsigned int c[2]; +}; + +/** + * struct bch_control - BCH control structure + * @m: Galois field order + * @n: maximum codeword size in bits (= 2^m-1) + * @t: error correction capability in bits + * @ecc_bits: ecc exact size in bits, i.e. generator polynomial degree (<=m*t) + * @ecc_bytes: ecc max size (m*t bits) in bytes + * @a_pow_tab: Galois field GF(2^m) exponentiation lookup table + * @a_log_tab: Galois field GF(2^m) log lookup table + * @mod8_tab: remainder generator polynomial lookup tables + * @ecc_buf: ecc parity words buffer + * @ecc_buf2: ecc parity words buffer + * @xi_tab: GF(2^m) base for solving degree 2 polynomial roots + * @syn: syndrome buffer + * @cache: log-based polynomial representation buffer + * @elp: error locator polynomial + * @poly_2t: temporary polynomials of degree 2t + */ +struct bch_control { + unsigned int m; + unsigned int n; + unsigned int t; + unsigned int ecc_bits; + unsigned int ecc_bytes; +/* private: */ + uint16_t *a_pow_tab; + uint16_t *a_log_tab; + uint32_t *mod8_tab; + uint32_t *ecc_buf; + uint32_t *ecc_buf2; + unsigned int *xi_tab; + unsigned int *syn; + int *cache; + struct gf_poly *elp; + struct gf_poly *poly_2t[4]; +}; + +struct bch_control *init_bch(int m, int t, unsigned int prim_poly); + +void free_bch(struct bch_control *bch); + +void encode_bch(struct bch_control *bch, const uint8_t *data, + unsigned int len, uint8_t *ecc); + +int decode_bch(struct bch_control *bch, const uint8_t *data, unsigned int len, + const uint8_t *recv_ecc, const uint8_t *calc_ecc, + const unsigned int *syn, unsigned int *errloc); + +#endif /* _BCH_H */ |