linux-imx

/*

 * Cryptographic API.

 *

 * CRC32C chksum

 *

 *@Article{castagnoli-crc,

 * author =       { Guy Castagnoli and Stefan Braeuer and Martin Herrman},

 * title =        {{Optimization of Cyclic Redundancy-Check Codes with 24

 *                 and 32 Parity Bits}},

 * journal =      IEEE Transactions on Communication,

 * year =         {1993},

 * volume =       {41},

 * number =       {6},

 * pages =        {},

 * month =        {June},

 *}

 * Used by the iSCSI driver, possibly others, and derived from the

 * the iscsi-crc.c module of the linux-iscsi driver at

 * http://linux-iscsi.sourceforge.net.

 *

 * Following the example of lib/crc32, this function is intended to be

 * flexible and useful for all users.  Modules that currently have their

 * own crc32c, but hopefully may be able to use this one are:

 *  net/sctp (please add all your doco to here if you change to

 *            use this one!)

 *  <endoflist>

 *

 * Copyright (c) 2004 Cisco Systems, Inc.

 * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License as published by the Free

 * Software Foundation; either version 2 of the License, or (at your option)

 * any later version.

 *

 */

​

#include <asm/unaligned.h>

#include <crypto/internal/hash.h>

#include <linux/init.h>

#include <linux/module.h>

#include <linux/string.h>

#include <linux/kernel.h>

#include <linux/crc32.h>

​

#define CHKSUM_BLOCK_SIZE   1

#define CHKSUM_DIGEST_SIZE  4

​

struct chksum_ctx {

    u32 key;

};

​

struct chksum_desc_ctx {

    u32 crc;

};

​

/*

 * Steps through buffer one byte at at time, calculates reflected

 * crc using table.

 */

​

static int chksum_init(struct shash_desc *desc)

{