xref: /openbsd/sys/dev/acpi/acpiutil.c (revision 5af055cd)
1 /* $OpenBSD: acpiutil.c,v 1.8 2015/03/14 03:38:47 jsg Exp $ */
2 /*
3  * Copyright (c) 2005 Thorsten Lockert <tholo@sigmasoft.com>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include <sys/types.h>
19 #include <sys/systm.h>
20 #include <sys/device.h>
21 
22 #include <dev/acpi/acpivar.h>
23 
24 u_int
25 acpi_checksum(const void *v, size_t len)
26 {
27 	const u_char *p = v;
28 	u_char s = 0;
29 	int i;
30 
31 	for (i = 0; i < len; i++)
32 		s += p[i];
33 
34 	if (s)
35 		dnprintf(0,"\nacpi0: bad checksum at %p", v);
36 
37 	return (s);
38 }
39