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 <stand.h>
28#include <machine/stdarg.h>
29#include <bootstrap.h>
30#include <btxv86.h>
31#include "libi386.h"
32
33#include "platform/acfreebsd.h"
34#include "acconfig.h"
35#define ACPI_SYSTEM_XFACE
36#include "actypes.h"
37#include "actbl.h"
38
39/*
40 * Detect ACPI and export information about the ACPI BIOS into the
41 * environment.
42 */
43
44static ACPI_TABLE_RSDP	*biosacpi_find_rsdp(void);
45static ACPI_TABLE_RSDP	*biosacpi_search_rsdp(char *base, int length);
46
47#define RSDP_CHECKSUM_LENGTH 20
48
49void
50biosacpi_detect(void)
51{
52    ACPI_TABLE_RSDP	*rsdp;
53    char		buf[24];
54    int			revision;
55
56    feature_enable(FEATURE_EARLY_ACPI);
57
58    /* locate and validate the RSDP */
59    if ((rsdp = biosacpi_find_rsdp()) == NULL)
60	return;
61
62    /*
63     * Report the RSDP to the kernel. While this can be found with
64     * a BIOS boot, the RSDP may be elsewhere when booted from UEFI.
65     */
66    sprintf(buf, "0x%08x", VTOP(rsdp));
67    setenv("acpi.rsdp", buf, 1);
68    revision = rsdp->Revision;
69    if (revision == 0)
70	revision = 1;
71    sprintf(buf, "%d", revision);
72    setenv("acpi.revision", buf, 1);
73    strncpy(buf, rsdp->OemId, sizeof(rsdp->OemId));
74    buf[sizeof(rsdp->OemId)] = '\0';
75    setenv("acpi.oem", buf, 1);
76    sprintf(buf, "0x%08x", rsdp->RsdtPhysicalAddress);
77    setenv("acpi.rsdt", buf, 1);
78    if (revision >= 2) {
79	/* XXX extended checksum? */
80	sprintf(buf, "0x%016llx", rsdp->XsdtPhysicalAddress);
81	setenv("acpi.xsdt", buf, 1);
82	sprintf(buf, "%d", rsdp->Length);
83	setenv("acpi.xsdt_length", buf, 1);
84    }
85}
86
87/*
88 * Find the RSDP in low memory.  See section 5.2.2 of the ACPI spec.
89 */
90static ACPI_TABLE_RSDP *
91biosacpi_find_rsdp(void)
92{
93    ACPI_TABLE_RSDP	*rsdp;
94    uint16_t		*addr;
95
96    /* EBDA is the 1 KB addressed by the 16 bit pointer at 0x40E. */
97    addr = (uint16_t *)PTOV(0x40E);
98    if ((rsdp = biosacpi_search_rsdp((char *)(*addr << 4), 0x400)) != NULL)
99	return (rsdp);
100
101    /* Check the upper memory BIOS space, 0xe0000 - 0xfffff. */
102    if ((rsdp = biosacpi_search_rsdp((char *)0xe0000, 0x20000)) != NULL)
103	return (rsdp);
104
105    return (NULL);
106}
107
108static ACPI_TABLE_RSDP *
109biosacpi_search_rsdp(char *base, int length)
110{
111    ACPI_TABLE_RSDP	*rsdp;
112    uint8_t		*cp, sum;
113    int			ofs, idx;
114
115    /* search on 16-byte boundaries */
116    for (ofs = 0; ofs < length; ofs += 16) {
117	rsdp = (ACPI_TABLE_RSDP *)PTOV(base + ofs);
118
119	/* compare signature, validate checksum */
120	if (!strncmp(rsdp->Signature, ACPI_SIG_RSDP, strlen(ACPI_SIG_RSDP))) {
121	    cp = (uint8_t *)rsdp;
122	    sum = 0;
123	    for (idx = 0; idx < RSDP_CHECKSUM_LENGTH; idx++)
124		sum += *(cp + idx);
125	    if (sum != 0)
126		continue;
127	    return(rsdp);
128	}
129    }
130    return(NULL);
131}
132