Edit File: rslib.h
/* * include/linux/rslib.h * * Overview: * Generic Reed Solomon encoder / decoder library * * Copyright (C) 2004 Thomas Gleixner (tglx@linutronix.de) * * RS code lifted from reed solomon library written by Phil Karn * Copyright 2002 Phil Karn, KA9Q * * $Id: rslib.h,v 1.4 2005/11/07 11:14:52 gleixner Exp $ * * 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. */ #ifndef _RSLIB_H_ #define _RSLIB_H_ #include <linux/list.h> /** * struct rs_control - rs control structure * * @mm: Bits per symbol * @nn: Symbols per block (= (1<<mm)-1) * @alpha_to: log lookup table * @index_of: Antilog lookup table * @genpoly: Generator polynomial * @nroots: Number of generator roots = number of parity symbols * @fcr: First consecutive root, index form * @prim: Primitive element, index form * @iprim: prim-th root of 1, index form * @gfpoly: The primitive generator polynominal * @gffunc: Function to generate the field, if non-canonical representation * @users: Users of this structure * @list: List entry for the rs control list */ struct rs_control { int mm; int nn; uint16_t *alpha_to; uint16_t *index_of; uint16_t *genpoly; int nroots; int fcr; int prim; int iprim; int gfpoly; int (*gffunc)(int); int users; struct list_head list; }; /* General purpose RS codec, 8-bit data width, symbol width 1-15 bit */ #ifdef CONFIG_REED_SOLOMON_ENC8 int encode_rs8(struct rs_control *rs, uint8_t *data, int len, uint16_t *par, uint16_t invmsk); #endif #ifdef CONFIG_REED_SOLOMON_DEC8 int decode_rs8(struct rs_control *rs, uint8_t *data, uint16_t *par, int len, uint16_t *s, int no_eras, int *eras_pos, uint16_t invmsk, uint16_t *corr); #endif /* General purpose RS codec, 16-bit data width, symbol width 1-15 bit */ #ifdef CONFIG_REED_SOLOMON_ENC16 int encode_rs16(struct rs_control *rs, uint16_t *data, int len, uint16_t *par, uint16_t invmsk); #endif #ifdef CONFIG_REED_SOLOMON_DEC16 int decode_rs16(struct rs_control *rs, uint16_t *data, uint16_t *par, int len, uint16_t *s, int no_eras, int *eras_pos, uint16_t invmsk, uint16_t *corr); #endif /* Create or get a matching rs control structure */ struct rs_control *init_rs(int symsize, int gfpoly, int fcr, int prim, int nroots); struct rs_control *init_rs_non_canonical(int symsize, int (*func)(int), int fcr, int prim, int nroots); /* Release a rs control structure */ void free_rs(struct rs_control *rs); /** modulo replacement for galois field arithmetics * * @rs: the rs control structure * @x: the value to reduce * * where * rs->mm = number of bits per symbol * rs->nn = (2^rs->mm) - 1 * * Simple arithmetic modulo would return a wrong result for values * >= 3 * rs->nn */ static inline int rs_modnn(struct rs_control *rs, int x) { while (x >= rs->nn) { x -= rs->nn; x = (x >> rs->mm) + (x & rs->nn); } return x; } #endif