kernel / pub / scm / linux / kernel / git / linusw / linux-gpio / 7ce7d89f48834cefece7804d38fc5d85382edf77 / . / include / linux / bch.h

/* | |

* Generic binary BCH encoding/decoding library | |

* | |

* This program is free software; you can redistribute it and/or modify it | |

* under the terms of the GNU General Public License version 2 as published by | |

* the Free Software Foundation. | |

* | |

* This program is distributed in the hope that it will be useful, but WITHOUT | |

* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |

* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |

* more details. | |

* | |

* You should have received a copy of the GNU General Public License along with | |

* this program; if not, write to the Free Software Foundation, Inc., 51 | |

* Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |

* | |

* 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 | |

*/ | |

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]; | |

}; | |

struct bch_control *init_bch(int m, int t, unsigned int prim_poly); | |

void free_bch(struct bch_control *bch); | |

void encode_bch(struct bch_control *bch, const uint8_t *data, | |

unsigned int len, uint8_t *ecc); | |

int decode_bch(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 */ |