DynamicTablesPkg/Library/Acpi/Common/AcpiCedtLib/CedtGenerator.c - edk2 - Git at Google

 /** @file
   CEDT Table Generator

   Copyright (c) 2025, Google, Inc. All rights reserved. <BR>

   SPDX-License-Identifier: BSD-2-Clause-Patent

   @par Reference(s):
   - Compute Express Link Specification - Revision 3.0, August 1, 2022.

 **/

 #include <Library/AcpiLib.h>
 #include <Library/DebugLib.h>
 #include <Library/MemoryAllocationLib.h>
 #include <Protocol/AcpiTable.h>

 // Module specific include files.
 #include <AcpiTableGenerator.h>
 #include <ConfigurationManagerObject.h>
 #include <ConfigurationManagerHelper.h>
 #include <Library/TableHelperLib.h>
 #include <Protocol/ConfigurationManagerProtocol.h>

 #include <IndustryStandard/Cxl.h>
 #include <IndustryStandard/Acpi64.h>
 #include "Base.h"
 #include "IndustryStandard/Acpi10.h"
 #include "Library/BaseLib.h"

 /** ARM standard CEDT Generator

 Requirements:
   The following Configuration Manager Object(s) are required by
   this Generator:
   - EArchCommonObjCxlHostBridgeInfo
   - EArchCommonObjCxlFixedMemoryWindowInfo
 */

 /** Retrieve the CXL host bridge info.
 */
 GET_OBJECT_LIST (
   EObjNameSpaceArchCommon,
   EArchCommonObjCxlHostBridgeInfo,
   CM_ARCH_COMMON_CXL_HOST_BRIDGE_INFO
   );

 /** Retrieve the CXL fixed memory window info.
 */
 GET_OBJECT_LIST (
   EObjNameSpaceArchCommon,
   EArchCommonObjCxlFixedMemoryWindowInfo,
   CM_ARCH_COMMON_CXL_FIXED_MEMORY_WINDOW_INFO
   );

 #define EFI_ACPI_CEDT_CXL_VERSION_RCH_LENGTH_BYTES  SIZE_8KB
 #define EFI_ACPI_CEDT_CXL_VERSION_HB_LENGTH_BYTES   SIZE_64KB

 #define INVALID_INTERLEAVE_WAYS  (0xFF)
 #define INVALID_GRANULARITY      (0xFF)

 #define CFMWS_ALIGNMENT  SIZE_256MB

 /** Add the CXL Host Bridge Info to the CEDT table

   @param [in,out]  WritePointer    Address of a write pointer for the CEDT table.
                                    On return, this will point to the next write
                                    location.
   @param [in]  HostBridgeList      Pointer to the CXL host bridge list.
   @param [in]  HostBridgeCount     Count of CXL host bridges.
 **/
 STATIC
 VOID
 AddCxlHostBridgeList (
   IN OUT   UINT8                                **WritePointer,
   IN CONST CM_ARCH_COMMON_CXL_HOST_BRIDGE_INFO  *HostBridgeList,
   IN       UINT32                               HostBridgeCount
   )
 {
   EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_STRUCTURE  *Chbs;
   UINT32                                       Index;

   ASSERT (WritePointer != NULL);
   ASSERT (*WritePointer != NULL);

   for (Index = 0; Index < HostBridgeCount; Index++) {
     Chbs               = (EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_STRUCTURE *)*WritePointer;
     Chbs->Type         = EFI_ACPI_6_4_CEDT_STRUCTURE_TYPE_CXL_HOST_BRIDGE_STRUCTURE;
     Chbs->RecordLength = sizeof (EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_STRUCTURE);
     Chbs->CxlVersion   = HostBridgeList[Index].Version;
     Chbs->Uid          = HostBridgeList[Index].Uid;
     Chbs->Base         = HostBridgeList[Index].ComponentRegisterBase;
     Chbs->Length       = (Chbs->CxlVersion == EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_STRUCTURE_CXL_VERSION_HB) ?
                          EFI_ACPI_CEDT_CXL_VERSION_HB_LENGTH_BYTES :
                          EFI_ACPI_CEDT_CXL_VERSION_RCH_LENGTH_BYTES;
     Chbs->Reserved0 = EFI_ACPI_RESERVED_BYTE;
     Chbs->Reserved1 = EFI_ACPI_RESERVED_DWORD;

     *WritePointer += Chbs->RecordLength;
   }
 }

 /** Converts the literal number of interleave ways to register field encoding.

   @param [in]  NumberOfInterleaveWays Number of ways the memory is interleaved.

   @retval The register field encoding for the number of interleave ways.
 **/
 STATIC
 UINT8
 GetEncodedNumberOfInterleaveWays (
   IN UINT8  NumberOfInterleaveWays
   )
 {
   switch (NumberOfInterleaveWays) {
     case 1:  return EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_INTERLEAVE_WAYS_NONE;
     case 2:  return EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_INTERLEAVE_WAYS_2_WAY;
     case 3:  return EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_INTERLEAVE_WAYS_3_WAY;
     case 4:  return EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_INTERLEAVE_WAYS_4_WAY;
     case 6:  return EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_INTERLEAVE_WAYS_6_WAY;
     case 8:  return EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_INTERLEAVE_WAYS_8_WAY;
     case 12: return EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_INTERLEAVE_WAYS_12_WAY;
     case 16: return EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_INTERLEAVE_WAYS_16_WAY;
     default: return INVALID_INTERLEAVE_WAYS;
   }
 }

 /** Convert the literal interleave granularity to the register field encoding.

   @param [in]  InterleaveGranularity Granularity of the interleave in bytes.

   @retval The register field encoding for the interleave granularity.
 **/
 STATIC
 UINT8
 GetEncodedInterleaveGranularity (
   IN UINT32  InterleaveGranularity
   )
 {
   switch (InterleaveGranularity) {
     case 256:   return EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_INTERLEAVE_GRANULARITY_256B;
     case 512:   return EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_INTERLEAVE_GRANULARITY_512B;
     case 1024:  return EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_INTERLEAVE_GRANULARITY_1024B;
     case 2048:  return EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_INTERLEAVE_GRANULARITY_2048B;
     case 4096:  return EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_INTERLEAVE_GRANULARITY_4096B;
     case 8192:  return EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_INTERLEAVE_GRANULARITY_8192B;
     case 16384: return EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_INTERLEAVE_GRANULARITY_16384B;
     default:    return INVALID_GRANULARITY;
   }
 }

 /** Add the CXL Fixed Memory Window Info to the CEDT table

   @param [in,out]  WritePointer    Address of a write pointer for the CEDT table.
                                    On return, this will point to the next write
                                    location.
   @param [in]  WindowList          Pointer to the CXL fixed memory window info
                                    list.
   @param [in]  WindowCount         Count of CXL fixed memory windows.
   @param [in]  CfgMgrProtocol      ConfigManagerProtocol to query data from.
 **/
 STATIC
 EFI_STATUS
 AddCxlFixedMemoryWindowList (
   IN OUT   UINT8                                          **WritePointer,
   IN CONST CM_ARCH_COMMON_CXL_FIXED_MEMORY_WINDOW_INFO    *WindowList,
   IN       UINT32                                         WindowCount,
   IN  CONST EDKII_CONFIGURATION_MANAGER_PROTOCOL  *CONST  CfgMgrProtocol
   )
 {
   EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE  *Cfmws;
   UINT32                                               Index;
   UINT32                                               InterleaveTargetIndex;
   UINT64                                               Remainder;

   ASSERT (WritePointer != NULL);
   ASSERT (*WritePointer != NULL);

   for (Index = 0; Index < WindowCount; Index++) {
     Cfmws               = (EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE *)*WritePointer;
     Cfmws->Type         = EFI_ACPI_6_4_CEDT_STRUCTURE_TYPE_CXL_FIXED_MEMORY_WINDOW_STRUCTURE;
     Cfmws->RecordLength =
       sizeof (EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE) +
       (sizeof (UINT32) * WindowList[Index].NumberOfInterleaveWays);

     Cfmws->BaseHpa = WindowList[Index].BaseHostPhysicalAddress;
     DivU64x64Remainder (
       Cfmws->BaseHpa,
       CFMWS_ALIGNMENT,
       &Remainder
       );
     if (Remainder != 0) {
       DEBUG ((
         DEBUG_ERROR,
         "ERROR: CEDT: Unaligned window address: 0x%lx",
         Cfmws->BaseHpa
         ));
       return EFI_INVALID_PARAMETER;
     }

     Cfmws->WindowSize = WindowList[Index].WindowSizeBytes;
     DivU64x64Remainder (
       Cfmws->WindowSize,
       CFMWS_ALIGNMENT * WindowList[Index].NumberOfInterleaveWays,
       &Remainder
       );
     if (Remainder != 0) {
       DEBUG ((
         DEBUG_ERROR,
         "ERROR: CEDT: Unaligned window size: 0x%lx",
         Cfmws->WindowSize
         ));
       return EFI_INVALID_PARAMETER;
     }

     Cfmws->EncodedNumberOfInterleaveWays =
       GetEncodedNumberOfInterleaveWays (WindowList[Index].NumberOfInterleaveWays);

     Cfmws->InterleaveArithmetic = WindowList[Index].InterleaveArithmetic;
     if (Cfmws->InterleaveArithmetic > EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_INTERLEAVE_ARITHMETIC_MODULO_XOR) {
       DEBUG ((
         DEBUG_ERROR,
         "ERROR: CEDT: Invalid interleave arithmetic: 0x%d",
         Cfmws->InterleaveArithmetic
         ));
       return EFI_INVALID_PARAMETER;
     }

     Cfmws->WindowRestrictions = WindowList[Index].WindowRestrictions;
     if (Cfmws->WindowRestrictions &
         ~((EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_WINDOW_RESTRICTIONS_FIXED_DEVICE_CONFIGURATION << 1)-1))
     {
       DEBUG ((
         DEBUG_ERROR,
         "ERROR: CEDT: Invalid window restrictions: 0x%x",
         Cfmws->WindowRestrictions
         ));
       return EFI_INVALID_PARAMETER;
     }

     Cfmws->QtgId                           = WindowList[Index].QtgId;
     Cfmws->HostBridgeInterleaveGranularity =
       GetEncodedInterleaveGranularity (WindowList[Index].HostBridgeInterleaveGranularity);
     if (Cfmws->HostBridgeInterleaveGranularity == INVALID_GRANULARITY) {
       return EFI_INVALID_PARAMETER;
     }

     Cfmws->Reserved0 = EFI_ACPI_RESERVED_BYTE;
     Cfmws->Reserved1 = EFI_ACPI_RESERVED_DWORD;
     Cfmws->Reserved2 = EFI_ACPI_RESERVED_WORD;

     for (InterleaveTargetIndex = 0;
          InterleaveTargetIndex < WindowList[Index].NumberOfInterleaveWays;
          InterleaveTargetIndex++)
     {
       UINT32                               HostBridgeCount;
       CM_ARCH_COMMON_CXL_HOST_BRIDGE_INFO  *HostBridge;
       EFI_STATUS                           Status;

       Status = GetEArchCommonObjCxlHostBridgeInfo (
                  CfgMgrProtocol,
                  WindowList[Index].InterleaveTargetTokens[InterleaveTargetIndex],
                  &HostBridge,
                  &HostBridgeCount
                  );
       if (EFI_ERROR (Status) || (HostBridgeCount != 1)) {
         DEBUG ((
           DEBUG_ERROR,
           "ERROR: CEDT: Failed to find host bridge with token: %x",
           WindowList[Index].InterleaveTargetTokens[InterleaveTargetIndex]
           ));
         return Status;
       }

       Cfmws->InterleaveTargetList[InterleaveTargetIndex] = HostBridge->Uid;
     }

     *WritePointer += Cfmws->RecordLength;
   }

   return EFI_SUCCESS;
 }

 /** Construct the CEDT ACPI table.

   This function invokes the Configuration Manager protocol interface
   to get the required hardware information for generating the ACPI
   table.

   If this function allocates any resources then they must be freed
   in the FreeXXXXTableResources function.

   @param [in]  This           Pointer to the table generator.
   @param [in]  AcpiTableInfo  Pointer to the ACPI Table Info.
   @param [in]  CfgMgrProtocol Pointer to the Configuration Manager
                               Protocol Interface.
   @param [out] Table          Pointer to the constructed ACPI Table.

   @retval EFI_SUCCESS           Table generated successfully.
   @retval EFI_INVALID_PARAMETER A parameter is invalid.
   @retval EFI_NOT_FOUND         The required object was not found.
   @retval EFI_BAD_BUFFER_SIZE   The size returned by the Configuration
                                 Manager is less than the Object size for the
                                 requested object.
 **/
 STATIC
 EFI_STATUS
 EFIAPI
 BuildCedtTable (
   IN  CONST ACPI_TABLE_GENERATOR                  *CONST  This,
   IN  CONST CM_STD_OBJ_ACPI_TABLE_INFO            *CONST  AcpiTableInfo,
   IN  CONST EDKII_CONFIGURATION_MANAGER_PROTOCOL  *CONST  CfgMgrProtocol,
   OUT       EFI_ACPI_DESCRIPTION_HEADER          **CONST  Table
   )
 {
   EFI_STATUS                           Status;
   UINT32                               TableSize;
   UINT32                               Index;
   UINT32                               TotalInterleaveTargets;
   UINT8                                *WritePointer;
   UINT32                               HostBridgeCount;
   CM_ARCH_COMMON_CXL_HOST_BRIDGE_INFO  *HostBridgeList;

   UINT32                                       WindowCount;
   CM_ARCH_COMMON_CXL_FIXED_MEMORY_WINDOW_INFO  *WindowList;

   EFI_ACPI_6_4_CXL_EARLY_DISCOVERY_TABLE  *CedtTable;

   ASSERT (This != NULL);
   ASSERT (AcpiTableInfo != NULL);
   ASSERT (CfgMgrProtocol != NULL);
   ASSERT (Table != NULL);
   ASSERT (AcpiTableInfo->TableGeneratorId == This->GeneratorID);
   ASSERT (AcpiTableInfo->AcpiTableSignature == This->AcpiTableSignature);

   if ((AcpiTableInfo->AcpiTableRevision < This->MinAcpiTableRevision) ||
       (AcpiTableInfo->AcpiTableRevision > This->AcpiTableRevision))
   {
     DEBUG ((
       DEBUG_ERROR,
       "ERROR: CEDT: Requested table revision = %d, is not supported."
       "Supported table revision: Minimum = %d, Maximum = %d\n",
       AcpiTableInfo->AcpiTableRevision,
       This->MinAcpiTableRevision,
       This->AcpiTableRevision
       ));
     return EFI_INVALID_PARAMETER;
   }

   *Table = NULL;

   // Get CHBS objects.

   Status = GetEArchCommonObjCxlHostBridgeInfo (
              CfgMgrProtocol,
              CM_NULL_TOKEN,
              &HostBridgeList,
              &HostBridgeCount
              );
   if (EFI_ERROR (Status)) {
     DEBUG ((
       DEBUG_ERROR,
       "ERROR: CEDT: Failed to get CXL Host Bridge Information." \
       " Status = %r\n",
       Status
       ));
     goto error_handler;
   }

   DEBUG ((
     DEBUG_INFO,
     "CEDT: Host Bridge Count = %d\n",
     HostBridgeCount
     ));

   // Get CFMWS objects
   Status = GetEArchCommonObjCxlFixedMemoryWindowInfo (
              CfgMgrProtocol,
              CM_NULL_TOKEN,
              &WindowList,
              &WindowCount
              );
   if (EFI_ERROR (Status)) {
     DEBUG ((
       DEBUG_ERROR,
       "ERROR: CEDT: Failed to get CXL Fixed Memory Window Information." \
       " Status = %r\n",
       Status
       ));
     goto error_handler;
   }

   DEBUG ((
     DEBUG_INFO,
     "CEDT: Window Count = %d\n",
     WindowCount
     ));

   // Calculate the CEDT Table Size
   TableSize =
     sizeof (EFI_ACPI_6_4_CXL_EARLY_DISCOVERY_TABLE) +
     ((sizeof (EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_STRUCTURE) * HostBridgeCount));

   // CFMWS does not have a fixed size because the number of InterleaveTargets
   // can vary. Its size is given by 36 + (4*NumberOfInterleaveWays).
   //
   // Also validate that the provided interleave ways is compliant.
   TotalInterleaveTargets = 0;
   for (Index = 0; Index < WindowCount; Index++) {
     UINT8  InterleaveWays;
     InterleaveWays = WindowList[Index].NumberOfInterleaveWays;
     if (GetEncodedNumberOfInterleaveWays (InterleaveWays) == INVALID_INTERLEAVE_WAYS) {
       DEBUG ((
         DEBUG_ERROR,
         "ERROR: CEDT: Invalid interleave ways: %d",
         InterleaveWays
         ));
       Status = EFI_INVALID_PARAMETER;
       goto error_handler;
     }

     TotalInterleaveTargets += InterleaveWays;
   }

   TableSize += (TotalInterleaveTargets * sizeof (UINT32)) +
                (WindowCount * sizeof (EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE));

   *Table = (EFI_ACPI_DESCRIPTION_HEADER *)AllocateZeroPool (TableSize);
   if (*Table == NULL) {
     Status = EFI_OUT_OF_RESOURCES;
     DEBUG ((
       DEBUG_ERROR,
       "ERROR: CEDT: Failed to allocate memory for CEDT Table, Size = %d," \
       " Status = %r\n",
       TableSize,
       Status
       ));
     goto error_handler;
   }

   // Add ACPI header.
   CedtTable = (EFI_ACPI_6_4_CXL_EARLY_DISCOVERY_TABLE *)*Table;

   Status = AddAcpiHeader (
              CfgMgrProtocol,
              This,
              &CedtTable->Header,
              AcpiTableInfo,
              TableSize
              );
   if (EFI_ERROR (Status)) {
     DEBUG ((
       DEBUG_ERROR,
       "ERROR: CEDT: Failed to add ACPI header. Status = %r\n",
       Status
       ));
     goto error_handler;
   }

   WritePointer = (UINT8 *)&CedtTable->CedtStructure;

   // Populate CHBS entries.
   AddCxlHostBridgeList (
     &WritePointer,
     HostBridgeList,
     HostBridgeCount
     );

   // Populate CFMWS entries.
   Status = AddCxlFixedMemoryWindowList (
              &WritePointer,
              WindowList,
              WindowCount,
              CfgMgrProtocol
              );
   if (EFI_ERROR (Status)) {
     DEBUG ((
       DEBUG_ERROR,
       "ERROR: CEDT: Failed to add CFMWS. Status = %r\n",
       Status
       ));
     goto error_handler;
   }

   return Status;

 error_handler:
   if (*Table != NULL) {
     FreePool (*Table);
     *Table = NULL;
   }

   return Status;
 }

 /** Free any resources allocated for constructing the CEDT

   @param [in]      This           Pointer to the table generator.
   @param [in]      AcpiTableInfo  Pointer to the ACPI Table Info.
   @param [in]      CfgMgrProtocol Pointer to the Configuration Manager
                                   Protocol Interface.
   @param [in, out] Table          Pointer to the ACPI Table.

   @retval EFI_SUCCESS           The resources were freed successfully.
   @retval EFI_INVALID_PARAMETER The table pointer is NULL or invalid.
 **/
 STATIC
 EFI_STATUS
 EFIAPI
 FreeCedtTableResources (
   IN      CONST ACPI_TABLE_GENERATOR                  *CONST  This,
   IN      CONST CM_STD_OBJ_ACPI_TABLE_INFO            *CONST  AcpiTableInfo,
   IN      CONST EDKII_CONFIGURATION_MANAGER_PROTOCOL  *CONST  CfgMgrProtocol,
   IN OUT        EFI_ACPI_DESCRIPTION_HEADER          **CONST  Table
   )
 {
   ASSERT (This != NULL);
   ASSERT (AcpiTableInfo != NULL);
   ASSERT (CfgMgrProtocol != NULL);
   ASSERT (AcpiTableInfo->TableGeneratorId == This->GeneratorID);
   ASSERT (AcpiTableInfo->AcpiTableSignature == This->AcpiTableSignature);

   if ((Table == NULL) || (*Table == NULL)) {
     DEBUG ((DEBUG_ERROR, "ERROR: CEDT: Invalid Table Pointer\n"));
     ASSERT ((Table != NULL) && (*Table != NULL));
     return EFI_INVALID_PARAMETER;
   }

   FreePool (*Table);
   *Table = NULL;
   return EFI_SUCCESS;
 }

 /** This macro defines the CEDT Table Generator revision.
 */
 #define CEDT_GENERATOR_REVISION  CREATE_REVISION (1, 0)

 /** The interface for the CEDT Table Generator.
 */
 STATIC
 CONST
 ACPI_TABLE_GENERATOR  CedtGenerator = {
   // Generator ID
   CREATE_STD_ACPI_TABLE_GEN_ID (EStdAcpiTableIdCedt),
   // Generator Description
   L"ACPI.STD.CEDT.GENERATOR",
   // ACPI Table Signature
   EFI_ACPI_6_4_CXL_EARLY_DISCOVERY_TABLE_SIGNATURE,
   // ACPI Table Revision supported by this Generator
   EFI_ACPI_6_4_CEDT_CXL_EARLY_DISCOVERY_TABLE_REVISION_01,
   // Minimum supported ACPI Table Revision
   EFI_ACPI_6_4_CEDT_CXL_EARLY_DISCOVERY_TABLE_REVISION_01,
   // Creator ID
   TABLE_GENERATOR_CREATOR_ID,
   // Creator Revision
   CEDT_GENERATOR_REVISION,
   // Build Table function
   BuildCedtTable,
   // Free Resource function
   FreeCedtTableResources,
   // Extended build function not needed
   NULL,
   // Extended build function not implemented by the generator.
   // Hence extended free resource function is not required.
   NULL
 };

 /** Register the Generator with the ACPI Table Factory.

   @param [in]  ImageHandle  The handle to the image.
   @param [in]  SystemTable  Pointer to the System Table.

   @retval EFI_SUCCESS           The Generator is registered.
   @retval EFI_INVALID_PARAMETER A parameter is invalid.
   @retval EFI_ALREADY_STARTED   The Generator for the Table ID
                                 is already registered.
 **/
 EFI_STATUS
 EFIAPI
 AcpiCedtLibConstructor (
   IN  EFI_HANDLE        ImageHandle,
   IN  EFI_SYSTEM_TABLE  *SystemTable
   )
 {
   EFI_STATUS  Status;

   Status = RegisterAcpiTableGenerator (&CedtGenerator);
   DEBUG ((DEBUG_INFO, "CEDT: Register Generator. Status = %r\n", Status));
   ASSERT_EFI_ERROR (Status);
   return Status;
 }

 /** Deregister the Generator from the ACPI Table Factory.

   @param [in]  ImageHandle  The handle to the image.
   @param [in]  SystemTable  Pointer to the System Table.

   @retval EFI_SUCCESS           The Generator is deregistered.
   @retval EFI_INVALID_PARAMETER A parameter is invalid.
   @retval EFI_NOT_FOUND         The Generator is not registered.
 **/
 EFI_STATUS
 EFIAPI
 AcpiCedtLibDestructor (
   IN  EFI_HANDLE        ImageHandle,
   IN  EFI_SYSTEM_TABLE  *SystemTable
   )
 {
   EFI_STATUS  Status;

   Status = DeregisterAcpiTableGenerator (&CedtGenerator);
   DEBUG ((DEBUG_INFO, "CEDT: Deregister Generator. Status = %r\n", Status));
   ASSERT_EFI_ERROR (Status);
   return Status;
 }
	/** @file
	CEDT Table Generator

	Copyright (c) 2025, Google, Inc. All rights reserved. <BR>

	SPDX-License-Identifier: BSD-2-Clause-Patent

	@par Reference(s):
	- Compute Express Link Specification - Revision 3.0, August 1, 2022.

	**/

	#include <Library/AcpiLib.h>
	#include <Library/DebugLib.h>
	#include <Library/MemoryAllocationLib.h>
	#include <Protocol/AcpiTable.h>

	// Module specific include files.
	#include <AcpiTableGenerator.h>
	#include <ConfigurationManagerObject.h>
	#include <ConfigurationManagerHelper.h>
	#include <Library/TableHelperLib.h>
	#include <Protocol/ConfigurationManagerProtocol.h>

	#include <IndustryStandard/Cxl.h>
	#include <IndustryStandard/Acpi64.h>
	#include "Base.h"
	#include "IndustryStandard/Acpi10.h"
	#include "Library/BaseLib.h"

	/** ARM standard CEDT Generator

	Requirements:
	The following Configuration Manager Object(s) are required by
	this Generator:
	- EArchCommonObjCxlHostBridgeInfo
	- EArchCommonObjCxlFixedMemoryWindowInfo
	*/

	/** Retrieve the CXL host bridge info.
	*/
	GET_OBJECT_LIST (
	EObjNameSpaceArchCommon,
	EArchCommonObjCxlHostBridgeInfo,
	CM_ARCH_COMMON_CXL_HOST_BRIDGE_INFO
	);

	/** Retrieve the CXL fixed memory window info.
	*/
	GET_OBJECT_LIST (
	EObjNameSpaceArchCommon,
	EArchCommonObjCxlFixedMemoryWindowInfo,
	CM_ARCH_COMMON_CXL_FIXED_MEMORY_WINDOW_INFO
	);

	#define EFI_ACPI_CEDT_CXL_VERSION_RCH_LENGTH_BYTES SIZE_8KB
	#define EFI_ACPI_CEDT_CXL_VERSION_HB_LENGTH_BYTES SIZE_64KB

	#define INVALID_INTERLEAVE_WAYS (0xFF)
	#define INVALID_GRANULARITY (0xFF)

	#define CFMWS_ALIGNMENT SIZE_256MB

	/** Add the CXL Host Bridge Info to the CEDT table

	@param [in,out] WritePointer Address of a write pointer for the CEDT table.
	On return, this will point to the next write
	location.
	@param [in] HostBridgeList Pointer to the CXL host bridge list.
	@param [in] HostBridgeCount Count of CXL host bridges.
	**/
	STATIC
	VOID
	AddCxlHostBridgeList (
	IN OUT UINT8 **WritePointer,
	IN CONST CM_ARCH_COMMON_CXL_HOST_BRIDGE_INFO *HostBridgeList,
	IN UINT32 HostBridgeCount
	)
	{
	EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_STRUCTURE *Chbs;
	UINT32 Index;

	ASSERT (WritePointer != NULL);
	ASSERT (*WritePointer != NULL);

	for (Index = 0; Index < HostBridgeCount; Index++) {
	Chbs = (EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_STRUCTURE )WritePointer;
	Chbs->Type = EFI_ACPI_6_4_CEDT_STRUCTURE_TYPE_CXL_HOST_BRIDGE_STRUCTURE;
	Chbs->RecordLength = sizeof (EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_STRUCTURE);
	Chbs->CxlVersion = HostBridgeList[Index].Version;
	Chbs->Uid = HostBridgeList[Index].Uid;
	Chbs->Base = HostBridgeList[Index].ComponentRegisterBase;
	Chbs->Length = (Chbs->CxlVersion == EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_STRUCTURE_CXL_VERSION_HB) ?
	EFI_ACPI_CEDT_CXL_VERSION_HB_LENGTH_BYTES :
	EFI_ACPI_CEDT_CXL_VERSION_RCH_LENGTH_BYTES;
	Chbs->Reserved0 = EFI_ACPI_RESERVED_BYTE;
	Chbs->Reserved1 = EFI_ACPI_RESERVED_DWORD;

	*WritePointer += Chbs->RecordLength;
	}
	}

	/** Converts the literal number of interleave ways to register field encoding.

	@param [in] NumberOfInterleaveWays Number of ways the memory is interleaved.

	@retval The register field encoding for the number of interleave ways.
	**/
	STATIC
	UINT8
	GetEncodedNumberOfInterleaveWays (
	IN UINT8 NumberOfInterleaveWays
	)
	{
	switch (NumberOfInterleaveWays) {
	case 1: return EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_INTERLEAVE_WAYS_NONE;
	case 2: return EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_INTERLEAVE_WAYS_2_WAY;
	case 3: return EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_INTERLEAVE_WAYS_3_WAY;
	case 4: return EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_INTERLEAVE_WAYS_4_WAY;
	case 6: return EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_INTERLEAVE_WAYS_6_WAY;
	case 8: return EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_INTERLEAVE_WAYS_8_WAY;
	case 12: return EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_INTERLEAVE_WAYS_12_WAY;
	case 16: return EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_INTERLEAVE_WAYS_16_WAY;
	default: return INVALID_INTERLEAVE_WAYS;
	}
	}

	/** Convert the literal interleave granularity to the register field encoding.

	@param [in] InterleaveGranularity Granularity of the interleave in bytes.

	@retval The register field encoding for the interleave granularity.
	**/
	STATIC
	UINT8
	GetEncodedInterleaveGranularity (
	IN UINT32 InterleaveGranularity
	)
	{
	switch (InterleaveGranularity) {
	case 256: return EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_INTERLEAVE_GRANULARITY_256B;
	case 512: return EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_INTERLEAVE_GRANULARITY_512B;
	case 1024: return EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_INTERLEAVE_GRANULARITY_1024B;
	case 2048: return EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_INTERLEAVE_GRANULARITY_2048B;
	case 4096: return EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_INTERLEAVE_GRANULARITY_4096B;
	case 8192: return EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_INTERLEAVE_GRANULARITY_8192B;
	case 16384: return EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_INTERLEAVE_GRANULARITY_16384B;
	default: return INVALID_GRANULARITY;
	}
	}

	/** Add the CXL Fixed Memory Window Info to the CEDT table

	@param [in,out] WritePointer Address of a write pointer for the CEDT table.
	On return, this will point to the next write
	location.
	@param [in] WindowList Pointer to the CXL fixed memory window info
	list.
	@param [in] WindowCount Count of CXL fixed memory windows.
	@param [in] CfgMgrProtocol ConfigManagerProtocol to query data from.
	**/
	STATIC
	EFI_STATUS
	AddCxlFixedMemoryWindowList (
	IN OUT UINT8 **WritePointer,
	IN CONST CM_ARCH_COMMON_CXL_FIXED_MEMORY_WINDOW_INFO *WindowList,
	IN UINT32 WindowCount,
	IN CONST EDKII_CONFIGURATION_MANAGER_PROTOCOL *CONST CfgMgrProtocol
	)
	{
	EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE *Cfmws;
	UINT32 Index;
	UINT32 InterleaveTargetIndex;
	UINT64 Remainder;

	ASSERT (WritePointer != NULL);
	ASSERT (*WritePointer != NULL);

	for (Index = 0; Index < WindowCount; Index++) {
	Cfmws = (EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE )WritePointer;
	Cfmws->Type = EFI_ACPI_6_4_CEDT_STRUCTURE_TYPE_CXL_FIXED_MEMORY_WINDOW_STRUCTURE;
	Cfmws->RecordLength =
	sizeof (EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE) +
	(sizeof (UINT32) * WindowList[Index].NumberOfInterleaveWays);

	Cfmws->BaseHpa = WindowList[Index].BaseHostPhysicalAddress;
	DivU64x64Remainder (
	Cfmws->BaseHpa,
	CFMWS_ALIGNMENT,
	&Remainder
	);
	if (Remainder != 0) {
	DEBUG ((
	DEBUG_ERROR,
	"ERROR: CEDT: Unaligned window address: 0x%lx",
	Cfmws->BaseHpa
	));
	return EFI_INVALID_PARAMETER;
	}

	Cfmws->WindowSize = WindowList[Index].WindowSizeBytes;
	DivU64x64Remainder (
	Cfmws->WindowSize,
	CFMWS_ALIGNMENT * WindowList[Index].NumberOfInterleaveWays,
	&Remainder
	);
	if (Remainder != 0) {
	DEBUG ((
	DEBUG_ERROR,
	"ERROR: CEDT: Unaligned window size: 0x%lx",
	Cfmws->WindowSize
	));
	return EFI_INVALID_PARAMETER;
	}

	Cfmws->EncodedNumberOfInterleaveWays =
	GetEncodedNumberOfInterleaveWays (WindowList[Index].NumberOfInterleaveWays);

	Cfmws->InterleaveArithmetic = WindowList[Index].InterleaveArithmetic;
	if (Cfmws->InterleaveArithmetic > EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_INTERLEAVE_ARITHMETIC_MODULO_XOR) {
	DEBUG ((
	DEBUG_ERROR,
	"ERROR: CEDT: Invalid interleave arithmetic: 0x%d",
	Cfmws->InterleaveArithmetic
	));
	return EFI_INVALID_PARAMETER;
	}

	Cfmws->WindowRestrictions = WindowList[Index].WindowRestrictions;
	if (Cfmws->WindowRestrictions &
	~((EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE_WINDOW_RESTRICTIONS_FIXED_DEVICE_CONFIGURATION << 1)-1))
	{
	DEBUG ((
	DEBUG_ERROR,
	"ERROR: CEDT: Invalid window restrictions: 0x%x",
	Cfmws->WindowRestrictions
	));
	return EFI_INVALID_PARAMETER;
	}

	Cfmws->QtgId = WindowList[Index].QtgId;
	Cfmws->HostBridgeInterleaveGranularity =
	GetEncodedInterleaveGranularity (WindowList[Index].HostBridgeInterleaveGranularity);
	if (Cfmws->HostBridgeInterleaveGranularity == INVALID_GRANULARITY) {
	return EFI_INVALID_PARAMETER;
	}

	Cfmws->Reserved0 = EFI_ACPI_RESERVED_BYTE;
	Cfmws->Reserved1 = EFI_ACPI_RESERVED_DWORD;
	Cfmws->Reserved2 = EFI_ACPI_RESERVED_WORD;

	for (InterleaveTargetIndex = 0;
	InterleaveTargetIndex < WindowList[Index].NumberOfInterleaveWays;
	InterleaveTargetIndex++)
	{
	UINT32 HostBridgeCount;
	CM_ARCH_COMMON_CXL_HOST_BRIDGE_INFO *HostBridge;
	EFI_STATUS Status;

	Status = GetEArchCommonObjCxlHostBridgeInfo (
	CfgMgrProtocol,
	WindowList[Index].InterleaveTargetTokens[InterleaveTargetIndex],
	&HostBridge,
	&HostBridgeCount
	);
	if (EFI_ERROR (Status) \|\| (HostBridgeCount != 1)) {
	DEBUG ((
	DEBUG_ERROR,
	"ERROR: CEDT: Failed to find host bridge with token: %x",
	WindowList[Index].InterleaveTargetTokens[InterleaveTargetIndex]
	));
	return Status;
	}

	Cfmws->InterleaveTargetList[InterleaveTargetIndex] = HostBridge->Uid;
	}

	*WritePointer += Cfmws->RecordLength;
	}

	return EFI_SUCCESS;
	}

	/** Construct the CEDT ACPI table.

	This function invokes the Configuration Manager protocol interface
	to get the required hardware information for generating the ACPI
	table.

	If this function allocates any resources then they must be freed
	in the FreeXXXXTableResources function.

	@param [in] This Pointer to the table generator.
	@param [in] AcpiTableInfo Pointer to the ACPI Table Info.
	@param [in] CfgMgrProtocol Pointer to the Configuration Manager
	Protocol Interface.
	@param [out] Table Pointer to the constructed ACPI Table.

	@retval EFI_SUCCESS Table generated successfully.
	@retval EFI_INVALID_PARAMETER A parameter is invalid.
	@retval EFI_NOT_FOUND The required object was not found.
	@retval EFI_BAD_BUFFER_SIZE The size returned by the Configuration
	Manager is less than the Object size for the
	requested object.
	**/
	STATIC
	EFI_STATUS
	EFIAPI
	BuildCedtTable (
	IN CONST ACPI_TABLE_GENERATOR *CONST This,
	IN CONST CM_STD_OBJ_ACPI_TABLE_INFO *CONST AcpiTableInfo,
	IN CONST EDKII_CONFIGURATION_MANAGER_PROTOCOL *CONST CfgMgrProtocol,
	OUT EFI_ACPI_DESCRIPTION_HEADER **CONST Table
	)
	{
	EFI_STATUS Status;
	UINT32 TableSize;
	UINT32 Index;
	UINT32 TotalInterleaveTargets;
	UINT8 *WritePointer;
	UINT32 HostBridgeCount;
	CM_ARCH_COMMON_CXL_HOST_BRIDGE_INFO *HostBridgeList;

	UINT32 WindowCount;
	CM_ARCH_COMMON_CXL_FIXED_MEMORY_WINDOW_INFO *WindowList;

	EFI_ACPI_6_4_CXL_EARLY_DISCOVERY_TABLE *CedtTable;

	ASSERT (This != NULL);
	ASSERT (AcpiTableInfo != NULL);
	ASSERT (CfgMgrProtocol != NULL);
	ASSERT (Table != NULL);
	ASSERT (AcpiTableInfo->TableGeneratorId == This->GeneratorID);
	ASSERT (AcpiTableInfo->AcpiTableSignature == This->AcpiTableSignature);

	if ((AcpiTableInfo->AcpiTableRevision < This->MinAcpiTableRevision) \|\|
	(AcpiTableInfo->AcpiTableRevision > This->AcpiTableRevision))
	{
	DEBUG ((
	DEBUG_ERROR,
	"ERROR: CEDT: Requested table revision = %d, is not supported."
	"Supported table revision: Minimum = %d, Maximum = %d\n",
	AcpiTableInfo->AcpiTableRevision,
	This->MinAcpiTableRevision,
	This->AcpiTableRevision
	));
	return EFI_INVALID_PARAMETER;
	}

	*Table = NULL;

	// Get CHBS objects.

	Status = GetEArchCommonObjCxlHostBridgeInfo (
	CfgMgrProtocol,
	CM_NULL_TOKEN,
	&HostBridgeList,
	&HostBridgeCount
	);
	if (EFI_ERROR (Status)) {
	DEBUG ((
	DEBUG_ERROR,
	"ERROR: CEDT: Failed to get CXL Host Bridge Information." \
	" Status = %r\n",
	Status
	));
	goto error_handler;
	}

	DEBUG ((
	DEBUG_INFO,
	"CEDT: Host Bridge Count = %d\n",
	HostBridgeCount
	));

	// Get CFMWS objects
	Status = GetEArchCommonObjCxlFixedMemoryWindowInfo (
	CfgMgrProtocol,
	CM_NULL_TOKEN,
	&WindowList,
	&WindowCount
	);
	if (EFI_ERROR (Status)) {
	DEBUG ((
	DEBUG_ERROR,
	"ERROR: CEDT: Failed to get CXL Fixed Memory Window Information." \
	" Status = %r\n",
	Status
	));
	goto error_handler;
	}

	DEBUG ((
	DEBUG_INFO,
	"CEDT: Window Count = %d\n",
	WindowCount
	));

	// Calculate the CEDT Table Size
	TableSize =
	sizeof (EFI_ACPI_6_4_CXL_EARLY_DISCOVERY_TABLE) +
	((sizeof (EFI_ACPI_6_4_CEDT_CXL_HOST_BRIDGE_STRUCTURE) * HostBridgeCount));

	// CFMWS does not have a fixed size because the number of InterleaveTargets
	// can vary. Its size is given by 36 + (4*NumberOfInterleaveWays).
	//
	// Also validate that the provided interleave ways is compliant.
	TotalInterleaveTargets = 0;
	for (Index = 0; Index < WindowCount; Index++) {
	UINT8 InterleaveWays;
	InterleaveWays = WindowList[Index].NumberOfInterleaveWays;
	if (GetEncodedNumberOfInterleaveWays (InterleaveWays) == INVALID_INTERLEAVE_WAYS) {
	DEBUG ((
	DEBUG_ERROR,
	"ERROR: CEDT: Invalid interleave ways: %d",
	InterleaveWays
	));
	Status = EFI_INVALID_PARAMETER;
	goto error_handler;
	}

	TotalInterleaveTargets += InterleaveWays;
	}

	TableSize += (TotalInterleaveTargets * sizeof (UINT32)) +
	(WindowCount * sizeof (EFI_ACPI_6_4_CEDT_CXL_FIXED_MEMORY_WINDOW_STRUCTURE));

	Table = (EFI_ACPI_DESCRIPTION_HEADER )AllocateZeroPool (TableSize);
	if (*Table == NULL) {
	Status = EFI_OUT_OF_RESOURCES;
	DEBUG ((
	DEBUG_ERROR,
	"ERROR: CEDT: Failed to allocate memory for CEDT Table, Size = %d," \
	" Status = %r\n",
	TableSize,
	Status
	));
	goto error_handler;
	}

	// Add ACPI header.
	CedtTable = (EFI_ACPI_6_4_CXL_EARLY_DISCOVERY_TABLE )Table;

	Status = AddAcpiHeader (
	CfgMgrProtocol,
	This,
	&CedtTable->Header,
	AcpiTableInfo,
	TableSize
	);
	if (EFI_ERROR (Status)) {
	DEBUG ((
	DEBUG_ERROR,
	"ERROR: CEDT: Failed to add ACPI header. Status = %r\n",
	Status
	));
	goto error_handler;
	}

	WritePointer = (UINT8 *)&CedtTable->CedtStructure;

	// Populate CHBS entries.
	AddCxlHostBridgeList (
	&WritePointer,
	HostBridgeList,
	HostBridgeCount
	);

	// Populate CFMWS entries.
	Status = AddCxlFixedMemoryWindowList (
	&WritePointer,
	WindowList,
	WindowCount,
	CfgMgrProtocol
	);
	if (EFI_ERROR (Status)) {
	DEBUG ((
	DEBUG_ERROR,
	"ERROR: CEDT: Failed to add CFMWS. Status = %r\n",
	Status
	));
	goto error_handler;
	}

	return Status;

	error_handler:
	if (*Table != NULL) {
	FreePool (*Table);
	*Table = NULL;
	}

	return Status;
	}

	/** Free any resources allocated for constructing the CEDT

	@param [in] This Pointer to the table generator.
	@param [in] AcpiTableInfo Pointer to the ACPI Table Info.
	@param [in] CfgMgrProtocol Pointer to the Configuration Manager
	Protocol Interface.
	@param [in, out] Table Pointer to the ACPI Table.

	@retval EFI_SUCCESS The resources were freed successfully.
	@retval EFI_INVALID_PARAMETER The table pointer is NULL or invalid.
	**/
	STATIC
	EFI_STATUS
	EFIAPI
	FreeCedtTableResources (
	IN CONST ACPI_TABLE_GENERATOR *CONST This,
	IN CONST CM_STD_OBJ_ACPI_TABLE_INFO *CONST AcpiTableInfo,
	IN CONST EDKII_CONFIGURATION_MANAGER_PROTOCOL *CONST CfgMgrProtocol,
	IN OUT EFI_ACPI_DESCRIPTION_HEADER **CONST Table
	)
	{
	ASSERT (This != NULL);
	ASSERT (AcpiTableInfo != NULL);
	ASSERT (CfgMgrProtocol != NULL);
	ASSERT (AcpiTableInfo->TableGeneratorId == This->GeneratorID);
	ASSERT (AcpiTableInfo->AcpiTableSignature == This->AcpiTableSignature);

	if ((Table == NULL) \|\| (*Table == NULL)) {
	DEBUG ((DEBUG_ERROR, "ERROR: CEDT: Invalid Table Pointer\n"));
	ASSERT ((Table != NULL) && (*Table != NULL));
	return EFI_INVALID_PARAMETER;
	}

	FreePool (*Table);
	*Table = NULL;
	return EFI_SUCCESS;
	}

	/** This macro defines the CEDT Table Generator revision.
	*/
	#define CEDT_GENERATOR_REVISION CREATE_REVISION (1, 0)

	/** The interface for the CEDT Table Generator.
	*/
	STATIC
	CONST
	ACPI_TABLE_GENERATOR CedtGenerator = {
	// Generator ID
	CREATE_STD_ACPI_TABLE_GEN_ID (EStdAcpiTableIdCedt),
	// Generator Description
	L"ACPI.STD.CEDT.GENERATOR",
	// ACPI Table Signature
	EFI_ACPI_6_4_CXL_EARLY_DISCOVERY_TABLE_SIGNATURE,
	// ACPI Table Revision supported by this Generator
	EFI_ACPI_6_4_CEDT_CXL_EARLY_DISCOVERY_TABLE_REVISION_01,
	// Minimum supported ACPI Table Revision
	EFI_ACPI_6_4_CEDT_CXL_EARLY_DISCOVERY_TABLE_REVISION_01,
	// Creator ID
	TABLE_GENERATOR_CREATOR_ID,
	// Creator Revision
	CEDT_GENERATOR_REVISION,
	// Build Table function
	BuildCedtTable,
	// Free Resource function
	FreeCedtTableResources,
	// Extended build function not needed
	NULL,
	// Extended build function not implemented by the generator.
	// Hence extended free resource function is not required.
	NULL
	};

	/** Register the Generator with the ACPI Table Factory.

	@param [in] ImageHandle The handle to the image.
	@param [in] SystemTable Pointer to the System Table.

	@retval EFI_SUCCESS The Generator is registered.
	@retval EFI_INVALID_PARAMETER A parameter is invalid.
	@retval EFI_ALREADY_STARTED The Generator for the Table ID
	is already registered.
	**/
	EFI_STATUS
	EFIAPI
	AcpiCedtLibConstructor (
	IN EFI_HANDLE ImageHandle,
	IN EFI_SYSTEM_TABLE *SystemTable
	)
	{
	EFI_STATUS Status;

	Status = RegisterAcpiTableGenerator (&CedtGenerator);
	DEBUG ((DEBUG_INFO, "CEDT: Register Generator. Status = %r\n", Status));
	ASSERT_EFI_ERROR (Status);
	return Status;
	}

	/** Deregister the Generator from the ACPI Table Factory.

	@param [in] ImageHandle The handle to the image.
	@param [in] SystemTable Pointer to the System Table.

	@retval EFI_SUCCESS The Generator is deregistered.
	@retval EFI_INVALID_PARAMETER A parameter is invalid.
	@retval EFI_NOT_FOUND The Generator is not registered.
	**/
	EFI_STATUS
	EFIAPI
	AcpiCedtLibDestructor (
	IN EFI_HANDLE ImageHandle,
	IN EFI_SYSTEM_TABLE *SystemTable
	)
	{
	EFI_STATUS Status;

	Status = DeregisterAcpiTableGenerator (&CedtGenerator);
	DEBUG ((DEBUG_INFO, "CEDT: Deregister Generator. Status = %r\n", Status));
	ASSERT_EFI_ERROR (Status);
	return Status;
	}