1*4c6de856SChristian Hitz /* 2*4c6de856SChristian Hitz * Generic binary BCH encoding/decoding library 3*4c6de856SChristian Hitz * 4*4c6de856SChristian Hitz * This program is free software; you can redistribute it and/or modify it 5*4c6de856SChristian Hitz * under the terms of the GNU General Public License version 2 as published by 6*4c6de856SChristian Hitz * the Free Software Foundation. 7*4c6de856SChristian Hitz * 8*4c6de856SChristian Hitz * This program is distributed in the hope that it will be useful, but WITHOUT 9*4c6de856SChristian Hitz * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10*4c6de856SChristian Hitz * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 11*4c6de856SChristian Hitz * more details. 12*4c6de856SChristian Hitz * 13*4c6de856SChristian Hitz * You should have received a copy of the GNU General Public License along with 14*4c6de856SChristian Hitz * this program; if not, write to the Free Software Foundation, Inc., 51 15*4c6de856SChristian Hitz * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 16*4c6de856SChristian Hitz * 17*4c6de856SChristian Hitz * Copyright © 2011 Parrot S.A. 18*4c6de856SChristian Hitz * 19*4c6de856SChristian Hitz * Author: Ivan Djelic <ivan.djelic@parrot.com> 20*4c6de856SChristian Hitz * 21*4c6de856SChristian Hitz * Description: 22*4c6de856SChristian Hitz * 23*4c6de856SChristian Hitz * This library provides runtime configurable encoding/decoding of binary 24*4c6de856SChristian Hitz * Bose-Chaudhuri-Hocquenghem (BCH) codes. 25*4c6de856SChristian Hitz */ 26*4c6de856SChristian Hitz #ifndef _BCH_H 27*4c6de856SChristian Hitz #define _BCH_H 28*4c6de856SChristian Hitz 29*4c6de856SChristian Hitz #include <linux/types.h> 30*4c6de856SChristian Hitz 31*4c6de856SChristian Hitz /** 32*4c6de856SChristian Hitz * struct bch_control - BCH control structure 33*4c6de856SChristian Hitz * @m: Galois field order 34*4c6de856SChristian Hitz * @n: maximum codeword size in bits (= 2^m-1) 35*4c6de856SChristian Hitz * @t: error correction capability in bits 36*4c6de856SChristian Hitz * @ecc_bits: ecc exact size in bits, i.e. generator polynomial degree (<=m*t) 37*4c6de856SChristian Hitz * @ecc_bytes: ecc max size (m*t bits) in bytes 38*4c6de856SChristian Hitz * @a_pow_tab: Galois field GF(2^m) exponentiation lookup table 39*4c6de856SChristian Hitz * @a_log_tab: Galois field GF(2^m) log lookup table 40*4c6de856SChristian Hitz * @mod8_tab: remainder generator polynomial lookup tables 41*4c6de856SChristian Hitz * @ecc_buf: ecc parity words buffer 42*4c6de856SChristian Hitz * @ecc_buf2: ecc parity words buffer 43*4c6de856SChristian Hitz * @xi_tab: GF(2^m) base for solving degree 2 polynomial roots 44*4c6de856SChristian Hitz * @syn: syndrome buffer 45*4c6de856SChristian Hitz * @cache: log-based polynomial representation buffer 46*4c6de856SChristian Hitz * @elp: error locator polynomial 47*4c6de856SChristian Hitz * @poly_2t: temporary polynomials of degree 2t 48*4c6de856SChristian Hitz */ 49*4c6de856SChristian Hitz struct bch_control { 50*4c6de856SChristian Hitz unsigned int m; 51*4c6de856SChristian Hitz unsigned int n; 52*4c6de856SChristian Hitz unsigned int t; 53*4c6de856SChristian Hitz unsigned int ecc_bits; 54*4c6de856SChristian Hitz unsigned int ecc_bytes; 55*4c6de856SChristian Hitz /* private: */ 56*4c6de856SChristian Hitz uint16_t *a_pow_tab; 57*4c6de856SChristian Hitz uint16_t *a_log_tab; 58*4c6de856SChristian Hitz uint32_t *mod8_tab; 59*4c6de856SChristian Hitz uint32_t *ecc_buf; 60*4c6de856SChristian Hitz uint32_t *ecc_buf2; 61*4c6de856SChristian Hitz unsigned int *xi_tab; 62*4c6de856SChristian Hitz unsigned int *syn; 63*4c6de856SChristian Hitz int *cache; 64*4c6de856SChristian Hitz struct gf_poly *elp; 65*4c6de856SChristian Hitz struct gf_poly *poly_2t[4]; 66*4c6de856SChristian Hitz }; 67*4c6de856SChristian Hitz 68*4c6de856SChristian Hitz struct bch_control *init_bch(int m, int t, unsigned int prim_poly); 69*4c6de856SChristian Hitz 70*4c6de856SChristian Hitz void free_bch(struct bch_control *bch); 71*4c6de856SChristian Hitz 72*4c6de856SChristian Hitz void encode_bch(struct bch_control *bch, const uint8_t *data, 73*4c6de856SChristian Hitz unsigned int len, uint8_t *ecc); 74*4c6de856SChristian Hitz 75*4c6de856SChristian Hitz int decode_bch(struct bch_control *bch, const uint8_t *data, unsigned int len, 76*4c6de856SChristian Hitz const uint8_t *recv_ecc, const uint8_t *calc_ecc, 77*4c6de856SChristian Hitz const unsigned int *syn, unsigned int *errloc); 78*4c6de856SChristian Hitz 79*4c6de856SChristian Hitz #endif /* _BCH_H */ 80