1 /* $NetBSD: nand_crc.c,v 1.1 2011/02/26 18:07:31 ahoka Exp $ */
2
3 /*-
4 * Copyright (c) 2010 Department of Software Engineering,
5 * University of Szeged, Hungary
6 * Copyright (c) 2010 Adam Hoka <ahoka@NetBSD.org>
7 * All rights reserved.
8 *
9 * This code is derived from software contributed to The NetBSD Foundation
10 * by the Department of Software Engineering, University of Szeged, Hungary
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34 /* Implements CRC-16 as required by the ONFI 2.3 specification */
35
36 #include <sys/cdefs.h>
37 __KERNEL_RCSID(0, "$NetBSD: nand_crc.c,v 1.1 2011/02/26 18:07:31 ahoka Exp $");
38
39 #include "nand_crc.h"
40
41 uint16_t
nand_crc16(uint8_t * data,size_t len)42 nand_crc16(uint8_t *data, size_t len)
43 {
44 const uint16_t init = 0x4f4e;
45 const uint16_t polynom = 0x8005;
46 const uint16_t highbit = 0x0001 << 15;
47 uint16_t crc = init;
48 size_t i;
49 int j;
50
51 for (i = 0; i < len; i++) {
52 crc ^= data[i] << 8;
53
54 for (j = 0; j < 8; j++) {
55 if ((crc & highbit) != 0x00)
56 crc = (crc << 1) ^ polynom;
57 else
58 crc <<= 1;
59 }
60 }
61
62 return crc;
63 }
64