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Diffstat (limited to 'include/linux/crc16.h')
| -rw-r--r-- | include/linux/crc16.h | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/include/linux/crc16.h b/include/linux/crc16.h new file mode 100644 index 0000000..bdedf82 --- /dev/null +++ b/include/linux/crc16.h @@ -0,0 +1,44 @@ +/* + * 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 */ + |