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 GetSystemMemorySizeBelow4gb (
  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 (((UINTN)((Cmos0x35 << 8) + Cmos0x34) << 16) + SIZE_16MB);
  58 }
  59
  60
  61 STATIC
  62 UINT64
  63 GetSystemMemorySizeAbove4gb (
  64   )
  65 {
  66   UINT32 Size;
  67   UINTN  CmosIndex;
  68
  69   //
  70   // CMOS 0x5b-0x5d specifies the system memory above 4GB MB.
  71   // * CMOS(0x5d) is the most significant size byte
  72   // * CMOS(0x5c) is the middle size byte
  73   // * CMOS(0x5b) is the least significant size byte
  74   // * The size is specified in 64kb chunks
  75   //
  76
  77   Size = 0;
  78   for (CmosIndex = 0x5d; CmosIndex >= 0x5b; CmosIndex--) {
  79     Size = (UINT32) (Size << 8) + (UINT32) CmosRead8 (CmosIndex);
  80   }
  81
  82   return LShiftU64 (Size, 16);
  83 }
  84
  85
  86 /**
  87   Peform Memory Detection
  88
  89   @return EFI_SUCCESS     The PEIM initialized successfully.
  90
  91 **/
  92 EFI_PHYSICAL_ADDRESS
  93 MemDetect (
  94   )
  95 {
  96   EFI_STATUS                  Status;
  97   EFI_PHYSICAL_ADDRESS        MemoryBase;
  98   UINT64                      MemorySize;
  99   UINT64                      LowerMemorySize;
 100   UINT64                      UpperMemorySize;
 101
 102   DEBUG ((EFI_D_ERROR, "MemDetect called\n"));
 103
 104   //
 105   // Determine total memory size available
 106   //
 107   LowerMemorySize = GetSystemMemorySizeBelow4gb ();
 108   UpperMemorySize = GetSystemMemorySizeAbove4gb ();
 109
 110   //
 111   // Determine the range of memory to use during PEI
 112   //
 113   MemoryBase = PcdGet32 (PcdOvmfMemFvBase) + PcdGet32 (PcdOvmfMemFvSize);
 114   MemorySize = LowerMemorySize - MemoryBase;
 115   if (MemorySize > SIZE_64MB) {
 116     MemoryBase = LowerMemorySize - SIZE_64MB;
 117     MemorySize = SIZE_64MB;
 118   }
 119
 120   //
 121   // Publish this memory to the PEI Core
 122   //
 123   Status = PublishSystemMemory(MemoryBase, MemorySize);
 124   ASSERT_EFI_ERROR (Status);
 125
 126   //
 127   // Create memory HOBs
 128   //
 129   AddMemoryBaseSizeHob (MemoryBase, MemorySize);
 130   AddMemoryRangeHob (BASE_1MB, MemoryBase);
 131   AddMemoryRangeHob (0, BASE_512KB + BASE_128KB);
 132
 133   if (UpperMemorySize != 0) {
 134     AddUntestedMemoryBaseSizeHob (BASE_4GB, UpperMemorySize);
 135   }
 136
 137   return MemoryBase + MemorySize;
 138 }
 139