DynamicTablesPkg: AML Code generation for Resource data EndTag

Add a helper function AmlCodeGenEndTag() to generate AML Resource Data
EndTag. The EndTag resource data is automatically generated by the ASL
compiler at the end of a list of resource data elements. Therefore, an
equivalent function is not present in ASL.

However, AmlCodeGenEndTag() is useful when generating AML code for the
ResourceTemplate() macro.

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

DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlResourceDataCodeGen.h

@@ -104,4 +104,47 @@ AmlCodeGenRdRegister (
   OUT AML_DATA_NODE_HANDLE    *NewRdNode  OPTIONAL
   );
 
+/** Code generation for the EndTag resource data.
+
+  The EndTag resource data is automatically generated by the ASL compiler
+  at the end of a list of resource data elements. Thus, it doesn't have
+  a corresponding ASL function.
+
+  This function allocates memory to create a data node. It is the caller's
+  responsibility to either:
+   - attach this node to an AML tree;
+   - delete this node.
+
+  ACPI 6.4, s6.4.2.9 "End Tag":
+  "This checksum is generated such that adding it to the sum of all the data
+  bytes will produce a zero sum."
+  "If the checksum field is zero, the resource data is treated as if the
+  checksum operation succeeded. Configuration proceeds normally."
+
+  To avoid re-computing checksums, if a new resource data elements is
+  added/removed/modified in a list of resource data elements, the AmlLib
+  resets the checksum to 0.
+
+  @param [in]  CheckSum        CheckSum to store in the EndTag.
+                               To ignore/avoid computing the checksum,
+                               give 0.
+  @param [in]  ParentNode      If not NULL, add the generated node
+                               to the end of the variable list of
+                               argument of the ParentNode.
+                               The ParentNode must not initially contain
+                               an EndTag resource data element.
+  @param  [out] NewRdNode      If success, contains the generated node.
+
+  @retval EFI_SUCCESS             The function completed successfully.
+  @retval EFI_INVALID_PARAMETER   Invalid parameter.
+  @retval EFI_OUT_OF_RESOURCES    Could not allocate memory.
+**/
+EFI_STATUS
+EFIAPI
+AmlCodeGenEndTag (
+  IN  UINT8               CheckSum,   OPTIONAL
+  IN  AML_OBJECT_NODE   * ParentNode, OPTIONAL
+  OUT AML_DATA_NODE    ** NewRdNode   OPTIONAL
+  );
+
 #endif // AML_RESOURCE_DATA_CODE_GEN_H_