45 lines
1.1 KiB
C
45 lines
1.1 KiB
C
|
/*
|
||
|
|
* crc16.h - CRC-16 routine
|
||
|
|
*
|
||
|
|
* Implements the standard CRC-16, as used with 1-wire devices:
|
||
|
|
* Width 16
|
||
|
|
* Poly 0x8005 (x^16 + x^15 + x^2 + 1)
|
||
|
|
* Init 0
|
||
|
|
*
|
||
|
|
* For 1-wire devices, the CRC is stored inverted, LSB-first
|
||
|
|
*
|
||
|
|
* Example buffer with the CRC attached:
|
||
|
|
* 31 32 33 34 35 36 37 38 39 C2 44
|
||
|
|
*
|
||
|
|
* The CRC over a buffer with the CRC attached is 0xB001.
|
||
|
|
* So, if (crc16(0, buf, size) == 0xB001) then the buffer is valid.
|
||
|
|
*
|
||
|
|
* Refer to "Application Note 937: Book of iButton Standards" for details.
|
||
|
|
* http://www.maxim-ic.com/appnotes.cfm/appnote_number/937
|
||
|
|
*
|
||
|
|
* Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com>
|
||
|
|
*
|
||
|
|
* This source code is licensed under the GNU General Public License,
|
||
|
|
* Version 2. See the file COPYING for more details.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#ifndef __CRC16_H
|
||
|
|
#define __CRC16_H
|
||
|
|
|
||
|
|
#include <linux/types.h>
|
||
|
|
|
||
|
|
#define CRC16_INIT 0
|
||
|
|
#define CRC16_VALID 0xb001
|
||
|
|
|
||
|
|
extern u16 const crc16_table[256];
|
||
|
|
|
||
|
|
extern u16 crc16(u16 crc, const u8 *buffer, size_t len);
|
||
|
|
|
||
|
|
static inline u16 crc16_byte(u16 crc, const u8 data)
|
||
|
|
{
|
||
|
|
return (crc >> 8) ^ crc16_table[(crc ^ data) & 0xff];
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif /* __CRC16_H */
|
||
|
|
|