MdePkg: Add CDAT structure definitions

Add CXL CDAT structure definitions to newly introduced CxlCdat.h

Signed-off-by: Nick Graves <nicholasgraves@google.com>
Signed-off-by: Oleksandr Tymoshenko <ovt@google.com>

MdePkg/Include/IndustryStandard/CxlCdat.h

@@ -0,0 +1,149 @@
+/** @file
+  CXL CDAT structure definitions
+
+  This file contains the structure definitions based on the
+  Coherent Device Attribute Table (CDAT) Specification 1.01
+
+  Copyright (c) 2026, Google LLC. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#pragma once
+
+///
+/// Definition for the CDAT Header.
+/// Coherent Device Attribute Table 1.01 Specification.
+///
+typedef struct {
+  UINT32    Length;   // Length of the enture table in bytes.
+  UINT8     Revision; // Must be 1.
+  UINT8     Checksum; // Checksum value that results in sum of 0.
+  UINT8     Reserved[6];
+  UINT32    Sequence; // Sequence number to indicate changes in sub tables.
+} CXL_CDAT_HEADER;
+
+typedef struct {
+  CXL_CDAT_HEADER    Header;
+  /// Subtables, each beginning with CXL_CDAT_COMMON_SUBTABLE_HEADER.
+  UINT8              Data[];
+} CXL_CDAT_STRUCTURE;
+
+///
+/// CDAT Structure Types.
+/// Coherent Device Attribute Table 1.01 Specification.
+///
+typedef enum {
+  CxlCdatTypeDsmas   = 0,
+  CxlCdatTypeDslbis  = 1,
+  CxlCdatTypeDsmscis = 2,
+  CxlCdatTypeDsis    = 3,
+  CxlCdatTypeDsemts  = 4,
+  CxlCdatTypeSslbis  = 5,
+} CXL_CDAT_TYPE;
+
+typedef struct {
+  UINT8     Type; // CXL_CDAT_TYPE type.
+  UINT8     Reserved;
+  UINT16    Length; // Length of only the subtable in bytes.
+} CXL_CDAT_COMMON_SUBTABLE_HEADER;
+
+///
+/// Definition for the Device Scoped Memory Affinity Structure (DSMAS).
+/// Coherent Device Attribute Table 1.01 Specification.
+///
+/// The DSMAS table contains handles to Device Scoped Memory Affinity Domains
+/// (DSMAD, not a typo of DSMAS). A DSMAD is a contiguous Device Physical
+/// Address (DPA) range that should be treated as a distinct memory proximity
+/// domain.
+///
+/// Host-side software is expected to map either:
+///   * a non-interleaved DSMAD handle to a single SRAT proximity domain; or
+///   * an interleaved set of DSMAD handles to a single SRAT proximity domain.
+///
+typedef struct {
+  CXL_CDAT_COMMON_SUBTABLE_HEADER    Header;
+  UINT8                              DsmadHandle;
+  UINT8                              Flags;
+  UINT8                              Reserved[2];
+  UINT64                             DpaBase;
+  UINT64                             DpaLength;
+} CXL_CDAT_DEVICE_SCOPED_MEMORY_AFFINITY_STRUCTURE;
+
+///
+/// Definition for the Device Scoped Memory Latency and Bandwidth Structure.
+/// Coherent Device Attribute Table 1.01 Specification.
+///
+typedef struct {
+  CXL_CDAT_COMMON_SUBTABLE_HEADER    Header;
+  UINT8                              Handle;
+  UINT8                              Flags;
+  UINT8                              DataType;
+  UINT8                              Reserved0;
+  UINT64                             EntryBaseUnit;
+  UINT16                             Entry[3]; // See the spec for a full definition of this field.
+  UINT8                              Reserved1[2];
+} CXL_CDAT_DEVICE_SCOPED_LAT_BW_STRUCTURE;
+
+///
+/// Definition for the Device Scoped Memory Side Cache Information Structure
+/// Coherent Device Attribute Table 1.01 Specification.
+///
+typedef struct {
+  CXL_CDAT_COMMON_SUBTABLE_HEADER    Header;
+  UINT8                              DsmasHandle;
+  UINT8                              Flags;
+  UINT8                              Reserved[3];
+  UINT64                             MemorySideCacheSize;
+  UINT32                             CacheAttributes;
+} CXL_CDAT_DEVICE_SCOPED_MEMORY_SIDE_CACHE_INFO_STRUCTURE;
+
+///
+/// Definition for the Device Scoped Initiator Structure
+/// Coherent Device Attribute Table 1.01 Specification.
+///
+typedef struct {
+  CXL_CDAT_COMMON_SUBTABLE_HEADER    Header;
+  UINT8                              Flags;
+  UINT8                              Handle;
+  UINT8                              Reserved[2];
+} CXL_CDAT_DEVICE_SCOPED_INITIATOR_STRUCTURE;
+
+typedef enum {
+  CxlCdatEfiConventionalMemory   = 0,
+  CxlCdatEfiConventionalMemorySp = 1,
+  CxlCdatEfiReservedMemory       = 2,
+} CXL_CDAT_EFI_MEMORY_TYPE;
+
+///
+/// Definition for the Device Scoped EFI Memory Type Structure
+/// Coherent Device Attribute Table 1.01 Specification.
+///
+typedef struct {
+  CXL_CDAT_COMMON_SUBTABLE_HEADER    Header;
+  UINT8                              DsmasHandle;
+  UINT8                              EfiMemoryType;
+  UINT8                              Reserved[2];
+  UINT64                             DpaOffset;
+  UINT64                             DpaLength;
+} CXL_CDAT_DEVICE_SCOPED_EFI_MEMORY_TYPE_STRUCTURE;
+
+///
+/// Definition for the Switch Scoped Latency and Bandwidth Information Structure
+/// Coherent Device Attribute Table 1.01 Specification.
+///
+typedef struct {
+  UINT16    PortXId;
+  UINT16    PortYId;
+  UINT16    LatOrBw;
+  UINT16    Reserved;
+} CXL_CDAT_SSLBE_ENTRY;
+
+typedef struct {
+  CXL_CDAT_COMMON_SUBTABLE_HEADER    Header;
+  UINT8                              DataType;
+  UINT8                              Reserved[3];
+  UINT64                             EntryBaseUnit;
+  CXL_CDAT_SSLBE_ENTRY               Entry[];
+} CXL_CDAT_SWITCH_SCOPED_LAT_BW_INFO_STRUCTURE;