14c6de856SChristian Hitz /* 24c6de856SChristian Hitz * Generic binary BCH encoding/decoding library 34c6de856SChristian Hitz * 4*5b8031ccSTom Rini * SPDX-License-Identifier: GPL-2.0 54c6de856SChristian Hitz * 64c6de856SChristian Hitz * Copyright © 2011 Parrot S.A. 74c6de856SChristian Hitz * 84c6de856SChristian Hitz * Author: Ivan Djelic <ivan.djelic@parrot.com> 94c6de856SChristian Hitz * 104c6de856SChristian Hitz * Description: 114c6de856SChristian Hitz * 124c6de856SChristian Hitz * This library provides runtime configurable encoding/decoding of binary 134c6de856SChristian Hitz * Bose-Chaudhuri-Hocquenghem (BCH) codes. 144c6de856SChristian Hitz */ 154c6de856SChristian Hitz #ifndef _BCH_H 164c6de856SChristian Hitz #define _BCH_H 174c6de856SChristian Hitz 184c6de856SChristian Hitz #include <linux/types.h> 194c6de856SChristian Hitz 204c6de856SChristian Hitz /** 214c6de856SChristian Hitz * struct bch_control - BCH control structure 224c6de856SChristian Hitz * @m: Galois field order 234c6de856SChristian Hitz * @n: maximum codeword size in bits (= 2^m-1) 244c6de856SChristian Hitz * @t: error correction capability in bits 254c6de856SChristian Hitz * @ecc_bits: ecc exact size in bits, i.e. generator polynomial degree (<=m*t) 264c6de856SChristian Hitz * @ecc_bytes: ecc max size (m*t bits) in bytes 274c6de856SChristian Hitz * @a_pow_tab: Galois field GF(2^m) exponentiation lookup table 284c6de856SChristian Hitz * @a_log_tab: Galois field GF(2^m) log lookup table 294c6de856SChristian Hitz * @mod8_tab: remainder generator polynomial lookup tables 304c6de856SChristian Hitz * @ecc_buf: ecc parity words buffer 314c6de856SChristian Hitz * @ecc_buf2: ecc parity words buffer 324c6de856SChristian Hitz * @xi_tab: GF(2^m) base for solving degree 2 polynomial roots 334c6de856SChristian Hitz * @syn: syndrome buffer 344c6de856SChristian Hitz * @cache: log-based polynomial representation buffer 354c6de856SChristian Hitz * @elp: error locator polynomial 364c6de856SChristian Hitz * @poly_2t: temporary polynomials of degree 2t 374c6de856SChristian Hitz */ 384c6de856SChristian Hitz struct bch_control { 394c6de856SChristian Hitz unsigned int m; 404c6de856SChristian Hitz unsigned int n; 414c6de856SChristian Hitz unsigned int t; 424c6de856SChristian Hitz unsigned int ecc_bits; 434c6de856SChristian Hitz unsigned int ecc_bytes; 444c6de856SChristian Hitz /* private: */ 454c6de856SChristian Hitz uint16_t *a_pow_tab; 464c6de856SChristian Hitz uint16_t *a_log_tab; 474c6de856SChristian Hitz uint32_t *mod8_tab; 484c6de856SChristian Hitz uint32_t *ecc_buf; 494c6de856SChristian Hitz uint32_t *ecc_buf2; 504c6de856SChristian Hitz unsigned int *xi_tab; 514c6de856SChristian Hitz unsigned int *syn; 524c6de856SChristian Hitz int *cache; 534c6de856SChristian Hitz struct gf_poly *elp; 544c6de856SChristian Hitz struct gf_poly *poly_2t[4]; 554c6de856SChristian Hitz }; 564c6de856SChristian Hitz 574c6de856SChristian Hitz struct bch_control *init_bch(int m, int t, unsigned int prim_poly); 584c6de856SChristian Hitz 594c6de856SChristian Hitz void free_bch(struct bch_control *bch); 604c6de856SChristian Hitz 614c6de856SChristian Hitz void encode_bch(struct bch_control *bch, const uint8_t *data, 624c6de856SChristian Hitz unsigned int len, uint8_t *ecc); 634c6de856SChristian Hitz 644c6de856SChristian Hitz int decode_bch(struct bch_control *bch, const uint8_t *data, unsigned int len, 654c6de856SChristian Hitz const uint8_t *recv_ecc, const uint8_t *calc_ecc, 664c6de856SChristian Hitz const unsigned int *syn, unsigned int *errloc); 674c6de856SChristian Hitz 684c6de856SChristian Hitz #endif /* _BCH_H */ 69