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authorSakari Ailus <sakari.ailus@linux.intel.com>2018-07-17 16:19:17 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-07-23 12:44:52 +0200
commit2285e6d9f68912c786cfc46f798be42ef9800ae8 (patch)
tree28646f54a960e0dc257d4bf95c7b062a25f13eac /Documentation/acpi
parentACPI: property: Use data node name and reg property for graphs (diff)
downloadlinux-2285e6d9f68912c786cfc46f798be42ef9800ae8.tar.xz
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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: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'Documentation/acpi')
-rw-r--r--Documentation/acpi/dsd/data-node-references.txt31
1 files changed, 25 insertions, 6 deletions
diff --git a/Documentation/acpi/dsd/data-node-references.txt b/Documentation/acpi/dsd/data-node-references.txt
index 00c3b5fe1f2e..6e9a5f925edd 100644
--- a/Documentation/acpi/dsd/data-node-references.txt
+++ b/Documentation/acpi/dsd/data-node-references.txt
@@ -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" },
}
})
}