Commit 2285e6d9 authored by Sakari Ailus's avatar Sakari Ailus Committed by Rafael J. Wysocki
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ACPI: property: Document key numbering for hierarchical data extension refs 



As part of the hierarchical data extension key naming, introduce numbering
scheme for the nodes that may be referred to using hierarchical data
extension references. This allows iterating over particular kind of nodes
recognised by the node name whilst allowing numbering the nodes, bringing
ACPI to feature parity with DT in this respect.

Signed-off-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 18f1e58d

Documentation/acpi/dsd/data-node-references.txt

+25 −6
Original line number Diff line number Diff line
@@ -15,24 +15,43 @@ extension node which is referred to by the key shall lie directly under the 
parent object i.e. either the device object or another hierarchical data

extension node.



The keys in the hierarchical data nodes shall consist of the name of the node,

"@" character and the number of the node in hexadecimal notation (without pre-

or postfixes). The same ACPI object shall include the _DSD property extension

with a property "reg" that shall have the same numerical value as the number of

the node.



In case a hierarchical data extensions node has no numerical value, then the

"reg" property shall be omitted from the ACPI object's _DSD properties and the

"@" character and the number shall be omitted from the hierarchical data

extension key.





Example

-------



	In the ASL snippet below, the "reference" _DSD property [2] contains a

	device object reference to DEV0 and under that device object, a

	hierarchical data extension key "node" referring to the NODE object and

	lastly, a hierarchical data extension key "anothernode" referring to the

	ANOD object which is also the final target of the reference.

	hierarchical data extension key "node@1" referring to the NOD1 object

	and lastly, a hierarchical data extension key "anothernode" referring to

	the ANOD object which is also the final target node of the reference.



	Device (DEV0)

	{

	    Name (_DSD, Package () {

		ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),

		Package () {

		    Package () { "node", NODE },

		    Package () { "node@0", NOD0 },

		    Package () { "node@1", NOD1 },

		}

	    })

	    Name (NOD0, Package() {

		ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),

		Package () {

		    Package () { "random-property", 3 },

		}

	    })

	    Name (NODE, Package() {

	    Name (NOD1, Package() {

		ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),

		Package () {

		    Package () { "anothernode", ANOD },
@@ -51,7 +70,7 @@ Example 
	    Name (_DSD, Package () {

		ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),

		Package () {

		    Package () { "reference", ^DEV0, "node", "anothernode" },

		    Package () { "reference", ^DEV0, "node@1", "anothernode" },

		}

	    })

	}

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