Fix a bug about the iSCSI DHCP dependency issue.

[mirror_edk2.git] / IntelFrameworkModulePkg / Csm / LegacyBiosDxe / LegacyBda.c

/** @file\r
  This code fills in BDA (0x400) and EBDA (pointed to by 0x4xx)\r
  information. There is support for doing initializeation before\r
  Legacy16 is loaded and before a legacy boot is attempted.\r
\r
Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>\r
\r
This program and the accompanying materials\r
are licensed and made available under the terms and conditions\r
of the BSD License which accompanies this distribution.  The\r
full text of the license may be found at\r
http://opensource.org/licenses/bsd-license.php\r
\r
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
#include "LegacyBiosInterface.h"\r
\r
/**\r
  Fill in the standard BDA and EBDA stuff before Legacy16 load\r
\r
  @param  Private     Legacy BIOS Instance data\r
\r
  @retval EFI_SUCCESS It should always work.\r
\r
**/\r
EFI_STATUS\r
LegacyBiosInitBda (\r
  IN  LEGACY_BIOS_INSTANCE    *Private\r
  )\r
{\r
  BDA_STRUC *Bda;\r
  UINT8     *Ebda;\r
\r
  Bda   = (BDA_STRUC *) ((UINTN) 0x400);\r
  Ebda  = (UINT8 *) ((UINTN) 0x9fc00);\r
\r
  ZeroMem (Bda, 0x100);\r
  ZeroMem (Ebda, 0x400);\r
  //\r
  // 640k-1k for EBDA\r
  //\r
  Bda->MemSize        = 0x27f;\r
  Bda->KeyHead        = 0x1e;\r
  Bda->KeyTail        = 0x1e;\r
  Bda->FloppyData     = 0x00;\r
  Bda->FloppyTimeout  = 0xff;\r
\r
  Bda->KeyStart       = 0x001E;\r
  Bda->KeyEnd         = 0x003E;\r
  Bda->KeyboardStatus = 0x10;\r
  Bda->Ebda           = 0x9fc0;\r
\r
  //\r
  // Move LPT time out here and zero out LPT4 since some SCSI OPROMS\r
  // use this as scratch pad (LPT4 is Reserved)\r
  //\r
  Bda->Lpt1_2Timeout  = 0x1414;\r
  Bda->Lpt3_4Timeout  = 0x1400;\r
\r
  *Ebda               = 0x01;\r
\r
  return EFI_SUCCESS;\r
}\r