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("$FreeBSD$");
29
30#include <stand.h>
31#include <machine/stdarg.h>
32#include <bootstrap.h>
33#include <btxv86.h>
34#include "libi386.h"
35
36#include "platform/acfreebsd.h"
37#include "acconfig.h"
38#define ACPI_SYSTEM_XFACE
39#include "actypes.h"
40#include "actbl.h"
41
42/*
43 * Detect ACPI and export information about the ACPI BIOS into the
44 * environment.
45 */
46
47static ACPI_TABLE_RSDP	*biosacpi_find_rsdp(void);
48static ACPI_TABLE_RSDP	*biosacpi_search_rsdp(char *base, int length);
49
50#define RSDP_CHECKSUM_LENGTH 20
51
52void
53biosacpi_detect(void)
54{
55    ACPI_TABLE_RSDP	*rsdp;
56    char		buf[24];
57    int			revision;
58
59    /* locate and validate the RSDP */
60    if ((rsdp = biosacpi_find_rsdp()) == NULL)
61	return;
62
63    /* export values from the RSDP */
64    sprintf(buf, "0x%08x", VTOP(rsdp));
65    setenv("hint.acpi.0.rsdp", buf, 1);
66    revision = rsdp->Revision;
67    if (revision == 0)
68	revision = 1;
69    sprintf(buf, "%d", revision);
70    setenv("hint.acpi.0.revision", buf, 1);
71    strncpy(buf, rsdp->OemId, sizeof(rsdp->OemId));
72    buf[sizeof(rsdp->OemId)] = '\0';
73    setenv("hint.acpi.0.oem", buf, 1);
74    sprintf(buf, "0x%08x", rsdp->RsdtPhysicalAddress);
75    setenv("hint.acpi.0.rsdt", buf, 1);
76    if (revision >= 2) {
77	/* XXX extended checksum? */
78	sprintf(buf, "0x%016llx", rsdp->XsdtPhysicalAddress);
79	setenv("hint.acpi.0.xsdt", buf, 1);
80	sprintf(buf, "%d", rsdp->Length);
81	setenv("hint.acpi.0.xsdt_length", buf, 1);
82    }
83}
84
85/*
86 * Find the RSDP in low memory.  See section 5.2.2 of the ACPI spec.
87 */
88static ACPI_TABLE_RSDP *
89biosacpi_find_rsdp(void)
90{
91    ACPI_TABLE_RSDP	*rsdp;
92    uint16_t		*addr;
93
94    /* EBDA is the 1 KB addressed by the 16 bit pointer at 0x40E. */
95    addr = (uint16_t *)PTOV(0x40E);
96    if ((rsdp = biosacpi_search_rsdp((char *)(*addr << 4), 0x400)) != NULL)
97	return (rsdp);
98
99    /* Check the upper memory BIOS space, 0xe0000 - 0xfffff. */
100    if ((rsdp = biosacpi_search_rsdp((char *)0xe0000, 0x20000)) != NULL)
101	return (rsdp);
102
103    return (NULL);
104}
105
106static ACPI_TABLE_RSDP *
107biosacpi_search_rsdp(char *base, int length)
108{
109    ACPI_TABLE_RSDP	*rsdp;
110    u_int8_t		*cp, sum;
111    int			ofs, idx;
112
113    /* search on 16-byte boundaries */
114    for (ofs = 0; ofs < length; ofs += 16) {
115	rsdp = (ACPI_TABLE_RSDP *)PTOV(base + ofs);
116
117	/* compare signature, validate checksum */
118	if (!strncmp(rsdp->Signature, ACPI_SIG_RSDP, strlen(ACPI_SIG_RSDP))) {
119	    cp = (u_int8_t *)rsdp;
120	    sum = 0;
121	    for (idx = 0; idx < RSDP_CHECKSUM_LENGTH; idx++)
122		sum += *(cp + idx);
123	    if (sum != 0)
124		continue;
125	    return(rsdp);
126	}
127    }
128    return(NULL);
129}
130