7657ec1fcb
Add the crc16 routines, as used by w1 devices. Signed-off-by: Ben Gardner <bgardner@wabtec.com> Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
44 lines
1.1 KiB
C
44 lines
1.1 KiB
C
/*
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* crc16.h - CRC-16 routine
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*
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* Implements the standard CRC-16, as used with 1-wire devices:
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* Width 16
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* Poly 0x8005 (x^16 + x^15 + x^2 + 1)
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* Init 0
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*
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* For 1-wire devices, the CRC is stored inverted, LSB-first
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*
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* Example buffer with the CRC attached:
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* 31 32 33 34 35 36 37 38 39 C2 44
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*
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* The CRC over a buffer with the CRC attached is 0xB001.
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* So, if (crc16(0, buf, size) == 0xB001) then the buffer is valid.
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*
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* Refer to "Application Note 937: Book of iButton Standards" for details.
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* http://www.maxim-ic.com/appnotes.cfm/appnote_number/937
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*
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* Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com>
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*
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*/
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#ifndef __CRC16_H
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#define __CRC16_H
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#include <linux/types.h>
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#define CRC16_INIT 0
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#define CRC16_VALID 0xb001
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extern u16 const crc16_table[256];
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extern u16 crc16(u16 crc, const u8 *buffer, size_t len);
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static inline u16 crc16_byte(u16 crc, const u8 data)
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{
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return (crc >> 8) ^ crc16_table[(crc ^ data) & 0xff];
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}
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#endif /* __CRC16_H */
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