projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 49df18fa PA |
1 | /* -*- linux-c -*- ------------------------------------------------------- * |
| 2 | * | |
| 3 | * Copyright (C) 1991, 1992 Linus Torvalds | |
| 4 | * Copyright 2007 rPath, Inc. - All Rights Reserved | |
| 5 | * | |
| 6 | * Original APM BIOS checking by Stephen Rothwell, May 1994 | |
| 7 | * (sfr@canb.auug.org.au) | |
| 8 | * | |
| 9 | * This file is part of the Linux kernel, and is made available under | |
| 10 | * the terms of the GNU General Public License version 2. | |
| 11 | * | |
| 12 | * ----------------------------------------------------------------------- */ | |
| 13 | ||
| 14 | /* | |
| 49df18fa PA |
15 | * Get APM BIOS information |
| 16 | */ | |
| 17 | ||
| 18 | #include "boot.h" | |
| 19 | ||
| 49df18fa PA |
20 | int query_apm_bios(void) |
| 21 | { | |
| 22 | u16 ax, bx, cx, dx, di; | |
| 23 | u32 ebx, esi; | |
| 24 | u8 err; | |
| 25 | ||
| 26 | /* APM BIOS installation check */ | |
| 27 | ax = 0x5300; | |
| 28 | bx = cx = 0; | |
| 29 | asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp ; setc %0" | |
| 30 | : "=d" (err), "+a" (ax), "+b" (bx), "+c" (cx) | |
| 31 | : : "esi", "edi"); | |
| 32 | ||
| 33 | if (err) | |
| 34 | return -1; /* No APM BIOS */ | |
| 35 | ||
| 36 | if (bx != 0x504d) /* "PM" signature */ | |
| 37 | return -1; | |
| 38 | ||
| 1514ab09 | 39 | if (!(cx & 0x02)) /* 32 bits supported? */ |
| 49df18fa PA |
40 | return -1; |
| 41 | ||
| 42 | /* Disconnect first, just in case */ | |
| 43 | ax = 0x5304; | |
| 1a13286b | 44 | bx = 0; |
| 49df18fa | 45 | asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp" |
| 1a13286b PA |
46 | : "+a" (ax), "+b" (bx) |
| 47 | : : "ecx", "edx", "esi", "edi"); | |
| 49df18fa PA |
48 | |
| 49 | /* Paranoia */ | |
| 50 | ebx = esi = 0; | |
| 51 | cx = dx = di = 0; | |
| 52 | ||
| 53 | /* 32-bit connect */ | |
| 54 | asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp ; setc %6" | |
| 55 | : "=a" (ax), "+b" (ebx), "+c" (cx), "+d" (dx), | |
| 56 | "+S" (esi), "+D" (di), "=m" (err) | |
| 57 | : "a" (0x5303)); | |
| 58 | ||
| 59 | boot_params.apm_bios_info.cseg = ax; | |
| 60 | boot_params.apm_bios_info.offset = ebx; | |
| 61 | boot_params.apm_bios_info.cseg_16 = cx; | |
| 62 | boot_params.apm_bios_info.dseg = dx; | |
| 63 | boot_params.apm_bios_info.cseg_len = (u16)esi; | |
| 64 | boot_params.apm_bios_info.cseg_16_len = esi >> 16; | |
| 65 | boot_params.apm_bios_info.dseg_len = di; | |
| 66 | ||
| 67 | if (err) | |
| 68 | return -1; | |
| 69 | ||
| 70 | /* Redo the installation check as the 32-bit connect; | |
| 71 | some BIOSes return different flags this way... */ | |
| 72 | ||
| 73 | ax = 0x5300; | |
| 74 | bx = cx = 0; | |
| 75 | asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp ; setc %0" | |
| 76 | : "=d" (err), "+a" (ax), "+b" (bx), "+c" (cx) | |
| 77 | : : "esi", "edi"); | |
| 78 | ||
| 79 | if (err || bx != 0x504d) { | |
| 80 | /* Failure with 32-bit connect, try to disconect and ignore */ | |
| 81 | ax = 0x5304; | |
| 82 | bx = 0; | |
| 83 | asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp" | |
| 84 | : "+a" (ax), "+b" (bx) | |
| 85 | : : "ecx", "edx", "esi", "edi"); | |
| 86 | return -1; | |
| 87 | } | |
| 88 | ||
| 89 | boot_params.apm_bios_info.version = ax; | |
| 90 | boot_params.apm_bios_info.flags = cx; | |
| 91 | return 0; | |
| 92 | } | |
| 93 |