| /* 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 */ |