OvmfPkg/PlatformPei/MemDetect.c

   1 /**@file
   2   Memory Detection for Virtual Machines.
   3
   4   Copyright (c) 2006 - 2009, Intel Corporation. All rights reserved.<BR>
   5   This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 Module Name:
  14
  15   MemDetect.c
  16
  17 **/
  18
  19 //
  20 // The package level header files this module uses
  21 //
  22 #include <PiPei.h>
  23
  24 //
  25 // The Library classes this module consumes
  26 //
  27 #include <Library/DebugLib.h>
  28 #include <Library/HobLib.h>
  29 #include <Library/IoLib.h>
  30 #include <Library/PcdLib.h>
  31 #include <Library/PeimEntryPoint.h>
  32 #include <Library/ResourcePublicationLib.h>
  33
  34 #include "Platform.h"
  35 #include "Cmos.h"
  36
  37 STATIC
  38 UINTN
  39 GetSystemMemorySize (
  40   )
  41 {
  42   UINT8 Cmos0x34;
  43   UINT8 Cmos0x35;
  44
  45   //
  46   // CMOS 0x34/0x35 specifies the system memory above 16 MB.
  47   // * CMOS(0x35) is the high byte
  48   // * CMOS(0x34) is the low byte
  49   // * The size is specified in 64kb chunks
  50   // * Since this is memory above 16MB, the 16MB must be added
  51   //   into the calculation to get the total memory size.
  52   //
  53
  54   Cmos0x34 = (UINT8) CmosRead8 (0x34);
  55   Cmos0x35 = (UINT8) CmosRead8 (0x35);
  56
  57   return ((((Cmos0x35 << 8) + Cmos0x34) << 16) + SIZE_16MB);
  58 }
  59
  60
  61 /**
  62   Peform Memory Detection
  63
  64   @return EFI_SUCCESS     The PEIM initialized successfully.
  65
  66 **/
  67 EFI_STATUS
  68 MemDetect (
  69   )
  70 {
  71   EFI_STATUS                  Status;
  72   EFI_PHYSICAL_ADDRESS        MemoryBase;
  73   UINT64                      MemorySize;
  74   UINT64                      TotalMemorySize;
  75
  76   DEBUG ((EFI_D_ERROR, "MemDetect called\n"));
  77
  78   //
  79   // Determine total memory size available
  80   //
  81   TotalMemorySize = (UINT64)GetSystemMemorySize ();
  82
  83   //
  84   // Determine the range of memory to use during PEI
  85   //
  86   MemoryBase = PcdGet32 (PcdOvmfMemFvBase) + PcdGet32 (PcdOvmfMemFvSize);
  87   MemorySize = TotalMemorySize - MemoryBase;
  88   if (MemorySize > SIZE_16MB) {
  89     MemoryBase = TotalMemorySize - SIZE_16MB;
  90     MemorySize = SIZE_16MB;
  91   }
  92
  93   //
  94   // Publish this memory to the PEI Core
  95   //
  96   Status = PublishSystemMemory(MemoryBase, MemorySize);
  97   ASSERT_EFI_ERROR (Status);
  98
  99   //
 100   // Create memory HOBs
 101   //
 102   AddMemoryBaseSizeHob (MemoryBase, MemorySize);
 103   AddMemoryRangeHob (BASE_1MB, MemoryBase);
 104   AddMemoryRangeHob (0, BASE_512KB + BASE_128KB);
 105
 106   return EFI_SUCCESS;
 107 }
 108