| 1 | /* ----------------------------------------------------------------------- * |
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| 2 | * |
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| 3 | * Copyright 2009 Intel Corporation; author: H. Peter Anvin |
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| 4 | * |
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| 5 | * This program is free software; you can redistribute it and/or modify |
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| 6 | * it under the terms of the GNU General Public License as published by |
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| 7 | * the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, |
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| 8 | * Boston MA 02110-1301, USA; either version 2 of the License, or |
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| 9 | * (at your option) any later version; incorporated herein by reference. |
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| 10 | * |
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| 11 | * Based on code from the Linux kernel: |
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| 12 | * |
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| 13 | * Copyright (C) 1991, 1992 Linus Torvalds |
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| 14 | * Copyright 2007 rPath, Inc. - All Rights Reserved |
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| 15 | * |
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| 16 | * Original APM BIOS checking by Stephen Rothwell, May 1994 |
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| 17 | * (sfr@canb.auug.org.au) |
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| 18 | * |
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| 19 | * This file is part of the Linux kernel, and is made available under |
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| 20 | * the terms of the GNU General Public License version 2. |
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| 21 | * |
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| 22 | * ----------------------------------------------------------------------- */ |
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| 23 | |
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| 24 | /* |
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| 25 | * apm.c |
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| 26 | * |
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| 27 | * APM information for Multiboot |
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| 28 | */ |
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| 29 | |
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| 30 | #include "mboot.h" |
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| 31 | #include <com32.h> |
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| 32 | |
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| 33 | void mboot_apm(void) |
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| 34 | { |
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| 35 | static struct apm_info apm; |
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| 36 | com32sys_t ireg, oreg; |
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| 37 | |
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| 38 | memset(&ireg, 0, sizeof ireg); |
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| 39 | |
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| 40 | ireg.eax.w[0] = 0x5300; |
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| 41 | __intcall(0x15, &ireg, &oreg); |
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| 42 | |
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| 43 | if (oreg.eflags.l & EFLAGS_CF) |
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| 44 | return; /* No APM BIOS */ |
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| 45 | |
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| 46 | if (oreg.ebx.w[0] != 0x504d) |
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| 47 | return; /* No "PM" signature */ |
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| 48 | |
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| 49 | if (!(oreg.ecx.w[0] & 0x02)) |
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| 50 | return; /* 32 bits not supported */ |
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| 51 | |
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| 52 | /* Disconnect first, just in case */ |
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| 53 | memset(&ireg, 0, sizeof ireg); |
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| 54 | ireg.eax.b[0] = 0x04; |
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| 55 | __intcall(0x15, &ireg, &oreg); |
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| 56 | |
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| 57 | /* 32-bit connect */ |
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| 58 | ireg.eax.b[0] = 0x03; |
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| 59 | __intcall(0x15, &ireg, &oreg); |
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| 60 | |
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| 61 | apm.cseg = oreg.eax.w[0]; |
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| 62 | apm.offset = oreg.ebx.l; |
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| 63 | apm.cseg_16 = oreg.ecx.w[0]; |
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| 64 | apm.dseg_16 = oreg.edx.w[0]; |
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| 65 | apm.cseg_len = oreg.esi.w[0]; |
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| 66 | apm.cseg_16_len = oreg.esi.w[1]; |
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| 67 | apm.dseg_16_len = oreg.edi.w[0]; |
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| 68 | |
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| 69 | /* Redo the installation check as the 32-bit connect; |
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| 70 | some BIOSes return different flags this way... */ |
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| 71 | |
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| 72 | memset(&ireg, 0, sizeof ireg); |
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| 73 | ireg.eax.b[0] = 0x00; |
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| 74 | __intcall(0x15, &ireg, &oreg); |
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| 75 | |
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| 76 | if ((oreg.eflags.l & EFLAGS_CF) || (oreg.ebx.w[0] != 0x504d)) { |
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| 77 | /* Failure with 32-bit connect, try to disconect and ignore */ |
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| 78 | ireg.eax.b[0] = 0x04; |
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| 79 | __intcall(0x15, &ireg, NULL); |
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| 80 | return; |
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| 81 | } |
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| 82 | |
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| 83 | apm.version = oreg.eax.w[0]; |
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| 84 | |
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| 85 | mbinfo.apm_table = map_data(&apm, sizeof apm, 4, false); |
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| 86 | if (mbinfo.apm_table) |
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| 87 | mbinfo.flags |= MB_INFO_APM_TABLE; |
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| 88 | } |
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