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 * $FreeBSD: src/sys/boot/i386/libi386/biosacpi.c,v 1.7 2003/08/25 23:28:31 obrien Exp $
27 */
28
29 #include <stand.h>
30 #include <machine/stdarg.h>
31 #include <bootstrap.h>
32 #include <btxv86.h>
33 #include "libi386.h"
34
35 #include "acpi.h"
36
37 /*
38 * Detect ACPI and export information about the ACPI BIOS into the
39 * environment.
40 */
41
42 static ACPI_TABLE_RSDP *biosacpi_find_rsdp(void);
43 static ACPI_TABLE_RSDP *biosacpi_search_rsdp(char *base, int length);
44
45 #define RSDP_CHECKSUM_LENGTH 20
46
47 void
biosacpi_detect(void)48 biosacpi_detect(void)
49 {
50 ACPI_TABLE_RSDP *rsdp;
51 char buf[160];
52 int revision;
53
54 /* locate and validate the RSDP */
55 if ((rsdp = biosacpi_find_rsdp()) == NULL)
56 return;
57
58 /* export values from the RSDP */
59 sprintf(buf, "0x%08x", VTOP(rsdp));
60 setenv("hint.acpi.0.rsdp", buf, 1);
61 revision = rsdp->Revision;
62 if (revision == 0)
63 revision = 1;
64 sprintf(buf, "%d", revision);
65 setenv("hint.acpi.0.revision", buf, 1);
66 strncpy(buf, rsdp->OemId, sizeof(rsdp->OemId));
67 buf[sizeof(rsdp->OemId)] = '\0';
68 setenv("hint.acpi.0.oem", buf, 1);
69 sprintf(buf, "0x%08x", rsdp->RsdtPhysicalAddress);
70 setenv("hint.acpi.0.rsdt", buf, 1);
71 if (revision >= 2) {
72 /* XXX extended checksum? */
73 sprintf(buf, "0x%016jx", (uintmax_t)rsdp->XsdtPhysicalAddress);
74 setenv("hint.acpi.0.xsdt", buf, 1);
75 sprintf(buf, "%d", rsdp->Length);
76 setenv("hint.acpi.0.xsdt_length", buf, 1);
77 }
78 setenv("acpi_load", "YES", 1);
79 }
80
81 /*
82 * Find the RSDP in low memory. See "Finding the RSDP on IA-PC Systems" in
83 * the ACPI spec.
84 */
85 static ACPI_TABLE_RSDP *
biosacpi_find_rsdp(void)86 biosacpi_find_rsdp(void)
87 {
88 ACPI_TABLE_RSDP *rsdp;
89 uint16_t *addr;
90
91 /* EBDA is the 1 KB addressed by the 16 bit pointer at 0x40e. */
92 addr = (uint16_t *)PTOV(ACPI_EBDA_PTR_LOCATION);
93 if ((rsdp = biosacpi_search_rsdp((char *)(*addr << 4),
94 ACPI_EBDA_WINDOW_SIZE)) != NULL)
95 return (rsdp);
96
97 /* Check the upper memory BIOS space, 0xe0000 - 0xfffff. */
98 if ((rsdp = biosacpi_search_rsdp((char *)ACPI_HI_RSDP_WINDOW_BASE,
99 ACPI_HI_RSDP_WINDOW_SIZE)) != NULL)
100 return (rsdp);
101
102 return (NULL);
103 }
104
105 static ACPI_TABLE_RSDP *
biosacpi_search_rsdp(char * base,int length)106 biosacpi_search_rsdp(char *base, int length)
107 {
108 ACPI_TABLE_RSDP *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 = (ACPI_TABLE_RSDP *)PTOV(base + ofs);
115
116 /* compare signature, validate checksum */
117 if (!strncmp(rsdp->Signature, ACPI_SIG_RSDP, strlen(ACPI_SIG_RSDP))) {
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 continue;
124 return(rsdp);
125 }
126 }
127 return(NULL);
128 }
129