biosacpi.c revision 129195 
1/*-
2 * Copyright (c) 2001 Michael Smith <msmith@freebsd.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: head/sys/boot/i386/libi386/biosacpi.c 129195 2004-05-14 01:29:21Z jdp $");
29
30#include <stand.h>
31#include <machine/stdarg.h>
32#include <bootstrap.h>
33
34#include "acfreebsd.h"
35#include "acconfig.h"
36#define ACPI_SYSTEM_XFACE
37#include "actypes.h"
38#include "actbl.h"
39
40/*
41 * Detect ACPI and export information about the APCI BIOS into the
42 * environment.
43 */
44
45static RSDP_DESCRIPTOR	*biosacpi_find_rsdp(void);
46static RSDP_DESCRIPTOR	*biosacpi_search_rsdp(char *base, int length);
47
48#define RSDP_CHECKSUM_LENGTH 20
49
50void
51biosacpi_detect(void)
52{
53    RSDP_DESCRIPTOR	*rsdp;
54    char		buf[16];
55    int			revision;
56
57    /* XXX check the BIOS datestamp */
58
59    /* locate and validate the RSDP */
60    if ((rsdp = biosacpi_find_rsdp()) == NULL)
61	return;
62
63    /* export values from the RSDP */
64    revision = rsdp->Revision;
65    if (revision == 0)
66	revision = 1;
67    sprintf(buf, "%d", revision);
68    setenv("hint.acpi.0.revision", buf, 1);
69    strncpy(buf, rsdp->OemId, sizeof(rsdp->OemId));
70    buf[sizeof(rsdp->OemId)] = '\0';
71    setenv("hint.acpi.0.oem", buf, 1);
72    sprintf(buf, "0x%08x", rsdp->RsdtPhysicalAddress);
73    setenv("hint.acpi.0.rsdt", buf, 1);
74    if (revision >= 2) {
75	/* XXX extended checksum? */
76	sprintf(buf, "0x%016llx", rsdp->XsdtPhysicalAddress);
77	setenv("hint.acpi.0.xsdt", buf, 1);
78	sprintf(buf, "%d", rsdp->Length);
79	setenv("hint.acpi.0.xsdt_length", buf, 1);
80    }
81    /* XXX other tables? */
82
83    setenv("acpi_load", "YES", 1);
84}
85
86/*
87 * Find the RSDP in low memory.
88 */
89static RSDP_DESCRIPTOR *
90biosacpi_find_rsdp(void)
91{
92    RSDP_DESCRIPTOR	*rsdp;
93
94    /* search the EBDA */
95    if ((rsdp = biosacpi_search_rsdp((char *)0, 0x400)) != NULL)
96	return(rsdp);
97
98    /* search the BIOS space */
99    if ((rsdp = biosacpi_search_rsdp((char *)0xe0000, 0x20000)) != NULL)
100	return(rsdp);
101
102    return(NULL);
103}
104
105static RSDP_DESCRIPTOR *
106biosacpi_search_rsdp(char *base, int length)
107{
108    RSDP_DESCRIPTOR	*rsdp;
109    u_int8_t		*cp, sum;
110    int			ofs, idx;
111
112    /* search on 16-byte boundaries */
113    for (ofs = 0; ofs < length; ofs += 16) {
114	rsdp = (RSDP_DESCRIPTOR *)(base + ofs);
115
116	/* compare signature, validate checksum */
117	if (!strncmp(rsdp->Signature, RSDP_SIG, strlen(RSDP_SIG))) {
118	    cp = (u_int8_t *)rsdp;
119	    sum = 0;
120	    for (idx = 0; idx < RSDP_CHECKSUM_LENGTH; idx++)
121		sum += *(cp + idx);
122	    if (sum != 0) {
123		printf("acpi: bad RSDP checksum (%d)\n", sum);
124		continue;
125	    }
126	    return(rsdp);
127	}
128    }
129    return(NULL);
130}
131