1 Copyright (C) 2018 Intel Corporation
2 Author: Sakari Ailus <sakari.ailus@linux.intel.com>
5 Referencing hierarchical data nodes
6 -----------------------------------
8 ACPI in general allows referring to device objects in the tree only.
9 Hierarchical data extension nodes may not be referred to directly, hence this
10 document defines a scheme to implement such references.
12 A reference consist of the device object name followed by one or more
13 hierarchical data extension [1] keys. Specifically, the hierarchical data
14 extension node which is referred to by the key shall lie directly under the
15 parent object i.e. either the device object or another hierarchical data
21 In the ASL snippet below, the "reference" _DSD property [2] contains a
22 device object reference to DEV0 and under that device object, a
23 hierarchical data extension key "node" referring to the NODE object and
24 lastly, a hierarchical data extension key "anothernode" referring to the
25 ANOD object which is also the final target of the reference.
29 Name (_DSD, Package () {
30 ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
32 Package () { "node", NODE },
35 Name (NODE, Package() {
36 ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
38 Package () { "anothernode", ANOD },
41 Name (ANOD, Package() {
42 ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
44 Package () { "random-property", 0 },
51 Name (_DSD, Package () {
52 ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
54 Package () { "reference", ^DEV0, "node", "anothernode" },
63 [1] Hierarchical Data Extension UUID For _DSD.
64 <URL:http://www.uefi.org/sites/default/files/resources/_DSD-hierarchical-data-extension-UUID-v1.1.pdf>,
65 referenced 2018-07-17.
67 [2] Device Properties UUID For _DSD.
68 <URL:http://www.uefi.org/sites/default/files/resources/_DSD-device-properties-UUID.pdf>,
69 referenced 2016-10-04.