xref: /openbsd-src/sys/arch/amd64/stand/libsa/biosprobe.c (revision 2df76cc2a0aee2cb2166e3799b7bb5c3f883f83d)
1 /*	$OpenBSD: biosprobe.c,v 1.3 2014/03/29 18:09:28 guenther Exp $	*/
2 
3 /*
4  * Copyright (c) 2002 Tobias Weingartner
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  */
27 
28 #include <sys/param.h>
29 #include <machine/biosvar.h>
30 #include <machine/pio.h>
31 #include <dev/cons.h>
32 #include <sys/disklabel.h>
33 #include "disk.h"
34 #include "libsa.h"
35 #include "biosdev.h"
36 
37 
38 void *
getSYSCONFaddr(void)39 getSYSCONFaddr(void)
40 {
41 	u_int32_t status;
42 	u_int8_t *vers;
43 
44 	__asm volatile(DOINT(0x15) "\n\t"
45 	    "setc %%al\n\t"
46 	    : "=a" (status)
47 	    : "0" (0xC000)
48 	    : "%ebx", "%ecx", "%edx", "%esi", "%edi", "cc");
49 
50 	/* On failure we go for a NULL */
51 	if (status)
52 		return NULL;
53 
54 	/* Calculate where the version bytes are */
55 	vers = (void*)((BIOS_regs.biosr_es << 4) | BIOS_regs.biosr_bx);
56 	return vers;
57 }
58 
59 void *
getEBDAaddr(void)60 getEBDAaddr(void)
61 {
62 	u_int32_t status;
63 	u_int8_t *info;
64 
65 	info = getSYSCONFaddr();
66 
67 	if (!info)
68 		return NULL;
69 
70 	__asm volatile(DOINT(0x15) "\n\t"
71 	    "setc %%al"
72 	    : "=a" (status)
73 	    : "0" (0xC100)
74 	    : "%ebx", "%ecx", "%edx", "%esi", "%edi", "cc");
75 
76 	if (status)
77 		return NULL;
78 
79 	info = (void *)(BIOS_regs.biosr_es << 4);
80 
81 	return info;
82 }
83