/*	$OpenBSD: onewire_subr.c,v 1.2 2007/02/28 22:31:32 deraadt Exp $	*/

/*
 * Copyright (c) 2006 Alexander Yurchenko <grange@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/*
 * 1-Wire bus miscellaneous routines.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>

#include <dev/onewire/onewiredevs.h>
#include <dev/onewire/onewirereg.h>
#include <dev/onewire/onewirevar.h>

#ifdef ONEWIREVERBOSE
#include <dev/onewire/onewiredevs_data.h>
#endif

static const u_int8_t crctable[] = {
	0x00, 0x5e, 0xbc, 0xe2, 0x61, 0x3f, 0xdd, 0x83,
	0xc2, 0x9c, 0x7e, 0x20, 0xa3, 0xfd, 0x1f, 0x41,
	0x9d, 0xc3, 0x21, 0x7f, 0xfc, 0xa2, 0x40, 0x1e,
	0x5f, 0x01, 0xe3, 0xbd, 0x3e, 0x60, 0x82, 0xdc,
	0x23, 0x7d, 0x9f, 0xc1, 0x42, 0x1c, 0xfe, 0xa0,
	0xe1, 0xbf, 0x5d, 0x03, 0x80, 0xde, 0x3c, 0x62,
	0xbe, 0xe0, 0x02, 0x5c, 0xdf, 0x81, 0x63, 0x3d,
	0x7c, 0x22, 0xc0, 0x9e, 0x1d, 0x43, 0xa1, 0xff,
	0x46, 0x18, 0xfa, 0xa4, 0x27, 0x79, 0x9b, 0xc5,
	0x84, 0xda, 0x38, 0x66, 0xe5, 0xbb, 0x59, 0x07,
	0xdb, 0x85, 0x67, 0x39, 0xba, 0xe4, 0x06, 0x58,
	0x19, 0x47, 0xa5, 0xfb, 0x78, 0x26, 0xc4, 0x9a,
	0x65, 0x3b, 0xd9, 0x87, 0x04, 0x5a, 0xb8, 0xe6,
	0xa7, 0xf9, 0x1b, 0x45, 0xc6, 0x98, 0x7a, 0x24,
	0xf8, 0xa6, 0x44, 0x1a, 0x99, 0xc7, 0x25, 0x7b,
	0x3a, 0x64, 0x86, 0xd8, 0x5b, 0x05, 0xe7, 0xb9,
	0x8c, 0xd2, 0x30, 0x6e, 0xed, 0xb3, 0x51, 0x0f,
	0x4e, 0x10, 0xf2, 0xac, 0x2f, 0x71, 0x93, 0xcd,
	0x11, 0x4f, 0xad, 0xf3, 0x70, 0x2e, 0xcc, 0x92,
	0xd3, 0x8d, 0x6f, 0x31, 0xb2, 0xec, 0x0e, 0x50,
	0xaf, 0xf1, 0x13, 0x4d, 0xce, 0x90, 0x72, 0x2c,
	0x6d, 0x33, 0xd1, 0x8f, 0x0c, 0x52, 0xb0, 0xee,
	0x32, 0x6c, 0x8e, 0xd0, 0x53, 0x0d, 0xef, 0xb1,
	0xf0, 0xae, 0x4c, 0x12, 0x91, 0xcf, 0x2d, 0x73,
	0xca, 0x94, 0x76, 0x28, 0xab, 0xf5, 0x17, 0x49,
	0x08, 0x56, 0xb4, 0xea, 0x69, 0x37, 0xd5, 0x8b,
	0x57, 0x09, 0xeb, 0xb5, 0x36, 0x68, 0x8a, 0xd4,
	0x95, 0xcb, 0x29, 0x77, 0xf4, 0xaa, 0x48, 0x16,
	0xe9, 0xb7, 0x55, 0x0b, 0x88, 0xd6, 0x34, 0x6a,
	0x2b, 0x75, 0x97, 0xc9, 0x4a, 0x14, 0xf6, 0xa8,
	0x74, 0x2a, 0xc8, 0x96, 0x15, 0x4b, 0xa9, 0xf7,
	0xb6, 0xe8, 0x0a, 0x54, 0xd7, 0x89, 0x6b, 0x35
};

int
onewire_crc(const void *buf, int len)
{
	const u_int8_t *p = buf;
	u_int8_t crc = 0;

	while (len--)
		crc = crctable[crc ^ *p++];

	return (crc);
}

const char *
onewire_famname(int type)
{
#ifdef ONEWIREVERBOSE
	const struct onewire_family *of;

	for (of = onewire_famtab; of->of_name != NULL; of++)
		if (of->of_type == type)
			return (of->of_name);
#endif

	return (NULL);
}

int
onewire_matchbyfam(struct onewire_attach_args *oa,
    const struct onewire_matchfam *fams, int nent)
{
	const struct onewire_matchfam *om;
	int i;

	for (i = 0, om = fams; i < nent; i++, om++)
		if (ONEWIRE_ROM_FAMILY_TYPE(oa->oa_rom) == om->om_type)
			return (1);

	return (0);
}
