AmlFieldListParser.h File Reference

#include <AmlNodeDefines.h>
#include <Stream/AmlStream.h>

Go to the source code of this file.

Functions
EFI_STATUS EFIAPI	AmlParseFieldList (IN AML_OBJECT_NODE *FieldNode, IN AML_STREAM *FStream, IN LIST_ENTRY *NameSpaceRefList)

Detailed Description

AML Field List.

Copyright (c) 2019 - 2020, Arm Limited. All rights reserved.

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

Definition in file AmlFieldListParser.h.

Function Documentation

AmlParseFieldList()

EFI_STATUS EFIAPI AmlParseFieldList	(	IN AML_OBJECT_NODE *	FieldNode,
		IN AML_STREAM *	FStream,
		IN LIST_ENTRY *	NameSpaceRefList
	)

Parse the FieldList contained in the stream.

Create an object node for each field element parsed in the field list available in the Stream, and add them to the variable list of arguments of the FieldNode.

Nodes that can have a field list are referred as field nodes. They have the AML_HAS_FIELD_LIST attribute.

According to the ACPI 6.3 specification, s20.2.5.2 "Named Objects Encoding", field elements can be:

• NamedField := NameSeg PkgLength;
• ReservedField := 0x00 PkgLength;
• AccessField := 0x01 AccessType AccessAttrib;
• ConnectField := <0x02 NameString> | <0x02 BufferData>;
• ExtendedAccessField := 0x03 AccessType ExtendedAccessAttrib AccessLength.

A small set of opcodes describes the field elements. They are referred as field opcodes. An AML_BYTE_ENCODING table has been created for field OpCodes. Field elements:

• don't have a SubOpCode;
• have at most 3 fixed arguments (as opposed to 6 for standard AML objects);
• don't have a variable list of arguments;
• only the NamedField field element is part of the AML namespace.

ConnectField's BufferData is a buffer node containing a single resource data element. NamedField field elements don't have an AML OpCode. NameSeg starts with a Char type and can thus be differentiated from the Opcodes for other fields. A pseudo OpCode has been created to simplify the parser.

The branch created from parsing a field node is as: (FieldNode) \ |- [FixedArg[0]][FixedArg[1]] # Fixed Arguments |- {(FieldElement[0])->(FieldElement[1])->...)} # Variable Arguments

With FieldElement[n] being one of NamedField, ReservedField, AccessField, ConnectField, ExtendedAccessField.

Parameters

[in]	FieldNode	Field node. Must have the AML_HAS_FIELD_LIST attribute.
[in]	FStream	Forward stream pointing to a field list. The stream must not be at its end.
[in]	NameSpaceRefList	List of namespace reference nodes, allowing to associate an absolute path to a node in the tree.

Return values

EFI_SUCCESS	The function completed successfully.
EFI_BUFFER_TOO_SMALL	No space left in the buffer.
EFI_INVALID_PARAMETER	Invalid parameter.
EFI_OUT_OF_RESOURCES	Could not allocate memory.

Definition at line 311 of file AmlFieldListParser.c.