1 /* SPDX-License-Identifier: GPL-2.0-only */ <<
2 /* 1 /*
3 * Generic binary BCH encoding/decoding librar 2 * Generic binary BCH encoding/decoding library
4 * 3 *
>> 4 * This program is free software; you can redistribute it and/or modify it
>> 5 * under the terms of the GNU General Public License version 2 as published by
>> 6 * the Free Software Foundation.
>> 7 *
>> 8 * This program is distributed in the hope that it will be useful, but WITHOUT
>> 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
>> 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
>> 11 * more details.
>> 12 *
>> 13 * You should have received a copy of the GNU General Public License along with
>> 14 * this program; if not, write to the Free Software Foundation, Inc., 51
>> 15 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
>> 16 *
5 * Copyright © 2011 Parrot S.A. 17 * Copyright © 2011 Parrot S.A.
6 * 18 *
7 * Author: Ivan Djelic <ivan.djelic@parrot.com 19 * Author: Ivan Djelic <ivan.djelic@parrot.com>
8 * 20 *
9 * Description: 21 * Description:
10 * 22 *
11 * This library provides runtime configurable 23 * This library provides runtime configurable encoding/decoding of binary
12 * Bose-Chaudhuri-Hocquenghem (BCH) codes. 24 * Bose-Chaudhuri-Hocquenghem (BCH) codes.
13 */ 25 */
14 #ifndef _BCH_H 26 #ifndef _BCH_H
15 #define _BCH_H 27 #define _BCH_H
16 28
17 #include <linux/types.h> 29 #include <linux/types.h>
18 30
19 /** 31 /**
20 * struct bch_control - BCH control structure 32 * struct bch_control - BCH control structure
21 * @m: Galois field order 33 * @m: Galois field order
22 * @n: maximum codeword size in bits 34 * @n: maximum codeword size in bits (= 2^m-1)
23 * @t: error correction capability in 35 * @t: error correction capability in bits
24 * @ecc_bits: ecc exact size in bits, i.e. g 36 * @ecc_bits: ecc exact size in bits, i.e. generator polynomial degree (<=m*t)
25 * @ecc_bytes: ecc max size (m*t bits) in byt 37 * @ecc_bytes: ecc max size (m*t bits) in bytes
26 * @a_pow_tab: Galois field GF(2^m) exponenti 38 * @a_pow_tab: Galois field GF(2^m) exponentiation lookup table
27 * @a_log_tab: Galois field GF(2^m) log looku 39 * @a_log_tab: Galois field GF(2^m) log lookup table
28 * @mod8_tab: remainder generator polynomial 40 * @mod8_tab: remainder generator polynomial lookup tables
29 * @ecc_buf: ecc parity words buffer 41 * @ecc_buf: ecc parity words buffer
30 * @ecc_buf2: ecc parity words buffer 42 * @ecc_buf2: ecc parity words buffer
31 * @xi_tab: GF(2^m) base for solving degre 43 * @xi_tab: GF(2^m) base for solving degree 2 polynomial roots
32 * @syn: syndrome buffer 44 * @syn: syndrome buffer
33 * @cache: log-based polynomial represent 45 * @cache: log-based polynomial representation buffer
34 * @elp: error locator polynomial 46 * @elp: error locator polynomial
35 * @poly_2t: temporary polynomials of degre 47 * @poly_2t: temporary polynomials of degree 2t
36 * @swap_bits: swap bits within data and synd <<
37 */ 48 */
38 struct bch_control { 49 struct bch_control {
39 unsigned int m; 50 unsigned int m;
40 unsigned int n; 51 unsigned int n;
41 unsigned int t; 52 unsigned int t;
42 unsigned int ecc_bits; 53 unsigned int ecc_bits;
43 unsigned int ecc_bytes; 54 unsigned int ecc_bytes;
44 /* private: */ 55 /* private: */
45 uint16_t *a_pow_tab; 56 uint16_t *a_pow_tab;
46 uint16_t *a_log_tab; 57 uint16_t *a_log_tab;
47 uint32_t *mod8_tab; 58 uint32_t *mod8_tab;
48 uint32_t *ecc_buf; 59 uint32_t *ecc_buf;
49 uint32_t *ecc_buf2; 60 uint32_t *ecc_buf2;
50 unsigned int *xi_tab; 61 unsigned int *xi_tab;
51 unsigned int *syn; 62 unsigned int *syn;
52 int *cache; 63 int *cache;
53 struct gf_poly *elp; 64 struct gf_poly *elp;
54 struct gf_poly *poly_2t[4]; 65 struct gf_poly *poly_2t[4];
55 bool swap_bits; <<
56 }; 66 };
57 67
58 struct bch_control *bch_init(int m, int t, uns !! 68 struct bch_control *init_bch(int m, int t, unsigned int prim_poly);
59 bool swap_bits); <<
60 69
61 void bch_free(struct bch_control *bch); !! 70 void free_bch(struct bch_control *bch);
62 71
63 void bch_encode(struct bch_control *bch, const !! 72 void encode_bch(struct bch_control *bch, const uint8_t *data,
64 unsigned int len, uint8_t *ecc 73 unsigned int len, uint8_t *ecc);
65 74
66 int bch_decode(struct bch_control *bch, const !! 75 int decode_bch(struct bch_control *bch, const uint8_t *data, unsigned int len,
67 const uint8_t *recv_ecc, const 76 const uint8_t *recv_ecc, const uint8_t *calc_ecc,
68 const unsigned int *syn, unsign 77 const unsigned int *syn, unsigned int *errloc);
69 78
70 #endif /* _BCH_H */ 79 #endif /* _BCH_H */
71 80
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