crc8.h

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/*
 * Copyright (c) 2011 Broadcom Corporation
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#ifndef __CRC8_H_
#define __CRC8_H_

#include <linux/types.h>

/* see usage of this value in crc8() description */
#define CRC8_INIT_VALUE     0xFF

/*
 * Return value of crc8() indicating valid message+crc. This is true
 * if a CRC is inverted before transmission. The CRC computed over the
 * whole received bitstream is _table[x], where x is the bit pattern
 * of the modification (almost always 0xff).
 */
#define CRC8_GOOD_VALUE(_table) (_table[0xFF])

/* required table size for crc8 algorithm */
#define CRC8_TABLE_SIZE         256

/* helper macro assuring right table size is used */
#define DECLARE_CRC8_TABLE(_table) \
    static u8 _table[CRC8_TABLE_SIZE]

void crc8_populate_lsb(u8 table[CRC8_TABLE_SIZE], u8 polynomial);

void crc8_populate_msb(u8 table[CRC8_TABLE_SIZE], u8 polynomial);

u8 crc8(const u8 table[CRC8_TABLE_SIZE], u8 *pdata, size_t nbytes, u8 crc);

#endif /* __CRC8_H_ */