에프에이리눅스 / 1611_0007_prime_oven

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kernel/linux-imx6_3.14.28/arch/x86/boot/apm.c 1.92 KB
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6b13f685e   김민수   BSP 최초 추가 
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  /* -*- linux-c -*- ------------------------------------------------------- *
   *
   *   Copyright (C) 1991, 1992 Linus Torvalds
   *   Copyright 2007 rPath, Inc. - All Rights Reserved
   *   Copyright 2009 Intel Corporation; author H. Peter Anvin
   *
   *   Original APM BIOS checking by Stephen Rothwell, May 1994
   *   (sfr@canb.auug.org.au)
   *
   *   This file is part of the Linux kernel, and is made available under
   *   the terms of the GNU General Public License version 2.
   *
   * ----------------------------------------------------------------------- */
  
  /*
   * Get APM BIOS information
   */
  
  #include "boot.h"
  
  int query_apm_bios(void)
  {
  	struct biosregs ireg, oreg;
  
  	/* APM BIOS installation check */
  	initregs(&ireg);
  	ireg.ah = 0x53;
  	intcall(0x15, &ireg, &oreg);
  
  	if (oreg.flags & X86_EFLAGS_CF)
  		return -1;		/* No APM BIOS */
  
  	if (oreg.bx != 0x504d)		/* "PM" signature */
  		return -1;
  
  	if (!(oreg.cx & 0x02))		/* 32 bits supported? */
  		return -1;
  
  	/* Disconnect first, just in case */
  	ireg.al = 0x04;
  	intcall(0x15, &ireg, NULL);
  
  	/* 32-bit connect */
  	ireg.al = 0x03;
  	intcall(0x15, &ireg, &oreg);
  
  	boot_params.apm_bios_info.cseg        = oreg.ax;
  	boot_params.apm_bios_info.offset      = oreg.ebx;
  	boot_params.apm_bios_info.cseg_16     = oreg.cx;
  	boot_params.apm_bios_info.dseg        = oreg.dx;
  	boot_params.apm_bios_info.cseg_len    = oreg.si;
  	boot_params.apm_bios_info.cseg_16_len = oreg.hsi;
  	boot_params.apm_bios_info.dseg_len    = oreg.di;
  
  	if (oreg.flags & X86_EFLAGS_CF)
  		return -1;
  
  	/* Redo the installation check as the 32-bit connect;
  	   some BIOSes return different flags this way... */
  
  	ireg.al = 0x00;
  	intcall(0x15, &ireg, &oreg);
  
  	if ((oreg.eflags & X86_EFLAGS_CF) || oreg.bx != 0x504d) {
  		/* Failure with 32-bit connect, try to disconect and ignore */
  		ireg.al = 0x04;
  		intcall(0x15, &ireg, NULL);
  		return -1;
  	}
  
  	boot_params.apm_bios_info.version = oreg.ax;
  	boot_params.apm_bios_info.flags   = oreg.cx;
  	return 0;
  }