1 /*
2 * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19 FILE_LICENCE ( GPL2_OR_LATER );
20
21 #include <stdint.h>
22 #include <string.h>
23 #include <errno.h>
24 #include <assert.h>
25 #include <gpxe/uaccess.h>
26 #include <gpxe/smbios.h>
27 #include <realmode.h>
28 #include <pnpbios.h>
29
30 /** @file
31 *
32 * System Management BIOS
33 *
34 */
35
36 /**
37 * Find SMBIOS
38 *
39 * @v smbios SMBIOS entry point descriptor structure to fill in
40 * @ret rc Return status code
41 */
bios_find_smbios(struct smbios * smbios)42 static int bios_find_smbios ( struct smbios *smbios ) {
43 union {
44 struct smbios_entry entry;
45 uint8_t bytes[256]; /* 256 is maximum length possible */
46 } u;
47 static unsigned int offset = 0;
48 size_t len;
49 unsigned int i;
50 uint8_t sum;
51
52 /* Try to find SMBIOS */
53 for ( ; offset < 0x10000 ; offset += 0x10 ) {
54
55 /* Read start of header and verify signature */
56 copy_from_real ( &u.entry, BIOS_SEG, offset,
57 sizeof ( u.entry ));
58 if ( u.entry.signature != SMBIOS_SIGNATURE )
59 continue;
60
61 /* Read whole header and verify checksum */
62 len = u.entry.len;
63 copy_from_real ( &u.bytes, BIOS_SEG, offset, len );
64 for ( i = 0 , sum = 0 ; i < len ; i++ ) {
65 sum += u.bytes[i];
66 }
67 if ( sum != 0 ) {
68 DBG ( "SMBIOS at %04x:%04x has bad checksum %02x\n",
69 BIOS_SEG, offset, sum );
70 continue;
71 }
72
73 /* Fill result structure */
74 DBG ( "Found SMBIOS v%d.%d entry point at %04x:%04x\n",
75 u.entry.major, u.entry.minor, BIOS_SEG, offset );
76 smbios->address = phys_to_user ( u.entry.smbios_address );
77 smbios->len = u.entry.smbios_len;
78 smbios->count = u.entry.smbios_count;
79 return 0;
80 }
81
82 DBG ( "No SMBIOS found\n" );
83 return -ENODEV;
84 }
85
86 PROVIDE_SMBIOS ( pcbios, find_smbios, bios_find_smbios );
87