DynamicTablesPkg: AML resource data helper

Resource data are defined in the ACPI 6.3 specification,
s6.4 "Resource Data Types for ACPI". They can be created
using the ASL ResourceTemplate () statement, cf s19.3.3
"ASL Resource Templates".

Resource data can be of the small or large type and are
defined by their encoding. The resource data is stored
in the Bytelist of a BufferOp node. To simplify
operations on resource data, the resource data parser
examines the Bytelist to detect the presence of resource
data. If the data matches the encoding of resource
data type(s), the parser fragments the resource data
buffer into resource data elements (data nodes) and
stores them in the variable arguments list of the
BufferOp node.

The resource data helper provides functions and macros
to assist operations on resource data elements.

Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
Reviewed-by: Alexei Fedorov <Alexei.Fedorov@arm.com>

DynamicTablesPkg/Library/Common/AmlLib/ResourceData/AmlResourceData.c

@@ -0,0 +1,103 @@
+/** @file
+  AML Resource Data.
+
+  Copyright (c) 2019 - 2020, Arm Limited. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+  @par Glossary:
+  - Rd or RD   - Resource Data
+  - Rds or RDS - Resource Data Small
+  - Rdl or RDL - Resource Data Large
+**/
+
+#include <ResourceData/AmlResourceData.h>
+
+/** Check whether the resource data has the input descriptor Id.
+
+  The small/large bit is included in the descriptor Id,
+  but the size bits are not included for small resource data elements.
+
+  @param  [in]  Header        Pointer to the first byte of a resource data
+                              element.
+  @param  [in]  DescriptorId  The descriptor to check against.
+
+  @retval TRUE    The resource data has the descriptor Id.
+  @retval FALSE   Otherwise.
+**/
+BOOLEAN
+EFIAPI
+AmlRdCompareDescId (
+  IN  CONST AML_RD_HEADER   * Header,
+  IN        AML_RD_HEADER     DescriptorId
+  )
+{
+  if (Header == NULL) {
+    ASSERT (0);
+    return FALSE;
+  }
+
+  if (AML_RD_IS_LARGE (Header)) {
+    return ((*Header ^ DescriptorId) == 0);
+  } else {
+    return (((*Header & AML_RD_SMALL_ID_MASK) ^ DescriptorId) == 0);
+  }
+}
+
+/** Get the descriptor Id of the resource data.
+
+  The small/large bit is included in the descriptor Id,
+  but the size bits are not included for small resource data elements.
+
+  @param  [in]  Header  Pointer to the first byte of a resource data.
+
+  @return A descriptor Id.
+**/
+AML_RD_HEADER
+EFIAPI
+AmlRdGetDescId (
+  IN  CONST AML_RD_HEADER   * Header
+  )
+{
+  if (Header == NULL) {
+    ASSERT (0);
+    return FALSE;
+  }
+
+  if (AML_RD_IS_LARGE (Header)) {
+    return *Header;
+  }
+
+  // Header is a small resource data element.
+  return *Header & AML_RD_SMALL_ID_MASK;
+}
+
+/** Get the size of a resource data element.
+
+  If the resource data element is of the large type, the Header
+  is expected to be at least 3 bytes long.
+
+  @param  [in]  Header  Pointer to the first byte of a resource data.
+
+  @return The size of the resource data element.
+**/
+UINT32
+EFIAPI
+AmlRdGetSize (
+  IN  CONST AML_RD_HEADER   * Header
+  )
+{
+  if (Header == NULL) {
+    ASSERT (0);
+    return FALSE;
+  }
+
+  if (AML_RD_IS_LARGE (Header)) {
+    return ((ACPI_LARGE_RESOURCE_HEADER*)Header)->Length +
+             sizeof (ACPI_LARGE_RESOURCE_HEADER);
+  }
+
+  // Header is a small resource data element.
+  return ((ACPI_SMALL_RESOURCE_HEADER*)Header)->Bits.Length +
+           sizeof (ACPI_SMALL_RESOURCE_HEADER);
+}