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 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