biosacpi.c revision 332154 
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: stable/11/stand/i386/libi386/biosacpi.c 332154 2018-04-06 21:37:25Z kevans $");
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    /*
64     * Report the RSDP to the kernel. While this can be found with
65     * a BIOS boot, the RSDP may be elsewhere when booted from UEFI.
66     * The old code used the 'hints' method to communite this to
67     * the kernel. However, while convenient, the 'hints' method
68     * is fragile and does not work when static hints are compiled
69     * into the kernel. Instead, move to setting different tunables
70     * that start with acpi. The old 'hints' can be removed before
71     * we branch for FreeBSD 12.
72     */
73    sprintf(buf, "0x%08x", VTOP(rsdp));
74    setenv("hint.acpi.0.rsdp", buf, 1);
75    setenv("acpi.rsdp", buf, 1);
76    revision = rsdp->Revision;
77    if (revision == 0)
78	revision = 1;
79    sprintf(buf, "%d", revision);
80    setenv("hint.acpi.0.revision", buf, 1);
81    setenv("acpi.revision", buf, 1);
82    strncpy(buf, rsdp->OemId, sizeof(rsdp->OemId));
83    buf[sizeof(rsdp->OemId)] = '\0';
84    setenv("hint.acpi.0.oem", buf, 1);
85    setenv("acpi.oem", buf, 1);
86    sprintf(buf, "0x%08x", rsdp->RsdtPhysicalAddress);
87    setenv("hint.acpi.0.rsdt", buf, 1);
88    setenv("acpi.rsdt", buf, 1);
89    if (revision >= 2) {
90	/* XXX extended checksum? */
91	sprintf(buf, "0x%016llx", rsdp->XsdtPhysicalAddress);
92	setenv("hint.acpi.0.xsdt", buf, 1);
93	setenv("acpi.xsdt", buf, 1);
94	sprintf(buf, "%d", rsdp->Length);
95	setenv("hint.acpi.0.xsdt_length", buf, 1);
96	setenv("acpi.xsdt_length", buf, 1);
97    }
98}
99
100/*
101 * Find the RSDP in low memory.  See section 5.2.2 of the ACPI spec.
102 */
103static ACPI_TABLE_RSDP *
104biosacpi_find_rsdp(void)
105{
106    ACPI_TABLE_RSDP	*rsdp;
107    uint16_t		*addr;
108
109    /* EBDA is the 1 KB addressed by the 16 bit pointer at 0x40E. */
110    addr = (uint16_t *)PTOV(0x40E);
111    if ((rsdp = biosacpi_search_rsdp((char *)(*addr << 4), 0x400)) != NULL)
112	return (rsdp);
113
114    /* Check the upper memory BIOS space, 0xe0000 - 0xfffff. */
115    if ((rsdp = biosacpi_search_rsdp((char *)0xe0000, 0x20000)) != NULL)
116	return (rsdp);
117
118    return (NULL);
119}
120
121static ACPI_TABLE_RSDP *
122biosacpi_search_rsdp(char *base, int length)
123{
124    ACPI_TABLE_RSDP	*rsdp;
125    uint8_t		*cp, sum;
126    int			ofs, idx;
127
128    /* search on 16-byte boundaries */
129    for (ofs = 0; ofs < length; ofs += 16) {
130	rsdp = (ACPI_TABLE_RSDP *)PTOV(base + ofs);
131
132	/* compare signature, validate checksum */
133	if (!strncmp(rsdp->Signature, ACPI_SIG_RSDP, strlen(ACPI_SIG_RSDP))) {
134	    cp = (uint8_t *)rsdp;
135	    sum = 0;
136	    for (idx = 0; idx < RSDP_CHECKSUM_LENGTH; idx++)
137		sum += *(cp + idx);
138	    if (sum != 0)
139		continue;
140	    return(rsdp);
141	}
142    }
143    return(NULL);
144}
145