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2b27bdcc | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
437aa565 ID |
2 | /* |
3 | * Generic binary BCH encoding/decoding library | |
4 | * | |
437aa565 ID |
5 | * Copyright © 2011 Parrot S.A. |
6 | * | |
7 | * Author: Ivan Djelic <ivan.djelic@parrot.com> | |
8 | * | |
9 | * Description: | |
10 | * | |
11 | * This library provides runtime configurable encoding/decoding of binary | |
12 | * Bose-Chaudhuri-Hocquenghem (BCH) codes. | |
13 | */ | |
14 | #ifndef _BCH_H | |
15 | #define _BCH_H | |
16 | ||
17 | #include <linux/types.h> | |
18 | ||
19 | /** | |
20 | * struct bch_control - BCH control structure | |
21 | * @m: Galois field order | |
22 | * @n: maximum codeword size in bits (= 2^m-1) | |
23 | * @t: error correction capability in bits | |
24 | * @ecc_bits: ecc exact size in bits, i.e. generator polynomial degree (<=m*t) | |
25 | * @ecc_bytes: ecc max size (m*t bits) in bytes | |
26 | * @a_pow_tab: Galois field GF(2^m) exponentiation lookup table | |
27 | * @a_log_tab: Galois field GF(2^m) log lookup table | |
28 | * @mod8_tab: remainder generator polynomial lookup tables | |
29 | * @ecc_buf: ecc parity words buffer | |
30 | * @ecc_buf2: ecc parity words buffer | |
31 | * @xi_tab: GF(2^m) base for solving degree 2 polynomial roots | |
32 | * @syn: syndrome buffer | |
33 | * @cache: log-based polynomial representation buffer | |
34 | * @elp: error locator polynomial | |
35 | * @poly_2t: temporary polynomials of degree 2t | |
1759279a | 36 | * @swap_bits: swap bits within data and syndrome bytes |
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37 | */ |
38 | struct bch_control { | |
39 | unsigned int m; | |
40 | unsigned int n; | |
41 | unsigned int t; | |
42 | unsigned int ecc_bits; | |
43 | unsigned int ecc_bytes; | |
44 | /* private: */ | |
45 | uint16_t *a_pow_tab; | |
46 | uint16_t *a_log_tab; | |
47 | uint32_t *mod8_tab; | |
48 | uint32_t *ecc_buf; | |
49 | uint32_t *ecc_buf2; | |
50 | unsigned int *xi_tab; | |
51 | unsigned int *syn; | |
52 | int *cache; | |
53 | struct gf_poly *elp; | |
54 | struct gf_poly *poly_2t[4]; | |
1759279a | 55 | bool swap_bits; |
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56 | }; |
57 | ||
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58 | struct bch_control *bch_init(int m, int t, unsigned int prim_poly, |
59 | bool swap_bits); | |
437aa565 | 60 | |
c8ae3f74 | 61 | void bch_free(struct bch_control *bch); |
437aa565 | 62 | |
c8ae3f74 | 63 | void bch_encode(struct bch_control *bch, const uint8_t *data, |
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64 | unsigned int len, uint8_t *ecc); |
65 | ||
c8ae3f74 | 66 | int bch_decode(struct bch_control *bch, const uint8_t *data, unsigned int len, |
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67 | const uint8_t *recv_ecc, const uint8_t *calc_ecc, |
68 | const unsigned int *syn, unsigned int *errloc); | |
69 | ||
70 | #endif /* _BCH_H */ |