xref: /openbsd/sys/arch/i386/stand/libsa/biosprobe.c (revision 8529ddd3)
1 /*	$OpenBSD: biosprobe.c,v 1.5 2014/03/29 18:09:29 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 "debug.h"
35 #include "libsa.h"
36 #include "biosdev.h"
37 
38 
39 void *
40 getSYSCONFaddr(void)
41 {
42 	u_int32_t status;
43 	u_int8_t *vers;
44 
45 	__asm volatile(DOINT(0x15) "\n\t"
46 	    "setc %%al\n\t"
47 	    : "=a" (status)
48 	    : "0" (0xC000)
49 	    : "%ebx", "%ecx", "%edx", "%esi", "%edi", "cc");
50 
51 	/* On failure we go for a NULL */
52 	if (status)
53 		return NULL;
54 
55 	/* Calculate where the version bytes are */
56 	vers = (void*)((BIOS_regs.biosr_es << 4) | BIOS_regs.biosr_bx);
57 	return vers;
58 }
59 
60 void *
61 getEBDAaddr(void)
62 {
63 	u_int32_t status;
64 	u_int8_t *info;
65 
66 	info = getSYSCONFaddr();
67 
68 	if (!info)
69 		return NULL;
70 
71 	__asm volatile(DOINT(0x15) "\n\t"
72 	    "setc %%al"
73 	    : "=a" (status)
74 	    : "0" (0xC100)
75 	    : "%ebx", "%ecx", "%edx", "%esi", "%edi", "cc");
76 
77 	if (status)
78 		return NULL;
79 
80 	info = (void *)(BIOS_regs.biosr_es << 4);
81 
82 	return info;
83 }
84