/* SPDX-License-Identifier: GPL-2.0-only */ /* * Generic binary BCH encoding/decoding library * * 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 <linux/types.h> /** * 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 * @swap_bits: swap bits within data and syndrome bytes */ 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]; bool swap_bits; }; struct bch_control *bch_init(int m, int t, unsigned int prim_poly, bool swap_bits); void bch_free(struct bch_control *bch); void bch_encode(struct bch_control *bch, const uint8_t *data, unsigned int len, uint8_t *ecc); int bch_decode(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 */