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3b53d304 PA |
1 | /* -*- linux-c -*- ------------------------------------------------------- * |
2 | * | |
3 | * Copyright (C) 1991, 1992 Linus Torvalds | |
4 | * Copyright 2007 rPath, Inc. - All Rights Reserved | |
5 | * | |
6 | * This file is part of the Linux kernel, and is made available under | |
7 | * the terms of the GNU General Public License version 2. | |
8 | * | |
9 | * ----------------------------------------------------------------------- */ | |
10 | ||
11 | /* | |
3b53d304 PA |
12 | * Get the MCA system description table |
13 | */ | |
14 | ||
15 | #include "boot.h" | |
16 | ||
17 | int query_mca(void) | |
18 | { | |
19 | u8 err; | |
20 | u16 es, bx, len; | |
21 | ||
22 | asm("pushw %%es ; " | |
23 | "int $0x15 ; " | |
24 | "setc %0 ; " | |
25 | "movw %%es, %1 ; " | |
26 | "popw %%es" | |
5593eaa8 | 27 | : "=acd" (err), "=acdSD" (es), "=b" (bx) |
3b53d304 PA |
28 | : "a" (0xc000)); |
29 | ||
30 | if (err) | |
31 | return -1; /* No MCA present */ | |
32 | ||
33 | set_fs(es); | |
34 | len = rdfs16(bx); | |
35 | ||
36 | if (len > sizeof(boot_params.sys_desc_table)) | |
37 | len = sizeof(boot_params.sys_desc_table); | |
38 | ||
39 | copy_from_fs(&boot_params.sys_desc_table, bx, len); | |
40 | return 0; | |
41 | } |