89 lines
2.4 KiB
C
89 lines
2.4 KiB
C
/* ----------------------------------------------------------------------- *
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*
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* Copyright 2009 Intel Corporation; author: H. Peter Anvin
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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* Boston MA 02110-1301, USA; either version 2 of the License, or
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* (at your option) any later version; incorporated herein by reference.
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*
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* Based on code from the Linux kernel:
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright 2007 rPath, Inc. - All Rights Reserved
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*
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* Original APM BIOS checking by Stephen Rothwell, May 1994
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* (sfr@canb.auug.org.au)
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*
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* This file is part of the Linux kernel, and is made available under
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* the terms of the GNU General Public License version 2.
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*
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* ----------------------------------------------------------------------- */
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/*
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* apm.c
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*
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* APM information for Multiboot
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*/
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#include "mboot.h"
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#include <com32.h>
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void mboot_apm(void)
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{
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static struct apm_info apm;
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com32sys_t ireg, oreg;
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memset(&ireg, 0, sizeof ireg);
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ireg.eax.w[0] = 0x5300;
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__intcall(0x15, &ireg, &oreg);
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if (oreg.eflags.l & EFLAGS_CF)
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return; /* No APM BIOS */
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if (oreg.ebx.w[0] != 0x504d)
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return; /* No "PM" signature */
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if (!(oreg.ecx.w[0] & 0x02))
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return; /* 32 bits not supported */
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/* Disconnect first, just in case */
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memset(&ireg, 0, sizeof ireg);
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ireg.eax.b[0] = 0x04;
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__intcall(0x15, &ireg, &oreg);
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/* 32-bit connect */
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ireg.eax.b[0] = 0x03;
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__intcall(0x15, &ireg, &oreg);
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apm.cseg = oreg.eax.w[0];
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apm.offset = oreg.ebx.l;
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apm.cseg_16 = oreg.ecx.w[0];
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apm.dseg_16 = oreg.edx.w[0];
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apm.cseg_len = oreg.esi.w[0];
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apm.cseg_16_len = oreg.esi.w[1];
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apm.dseg_16_len = oreg.edi.w[0];
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/* Redo the installation check as the 32-bit connect;
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some BIOSes return different flags this way... */
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memset(&ireg, 0, sizeof ireg);
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ireg.eax.b[0] = 0x00;
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__intcall(0x15, &ireg, &oreg);
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if ((oreg.eflags.l & EFLAGS_CF) || (oreg.ebx.w[0] != 0x504d)) {
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/* Failure with 32-bit connect, try to disconect and ignore */
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ireg.eax.b[0] = 0x04;
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__intcall(0x15, &ireg, NULL);
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return;
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}
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apm.version = oreg.eax.w[0];
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mbinfo.apm_table = map_data(&apm, sizeof apm, 4, false);
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if (mbinfo.apm_table)
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mbinfo.flags |= MB_INFO_APM_TABLE;
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}
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