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authorLinus Torvalds <torvalds@linux-foundation.org>2019-05-06 19:35:13 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-06 19:35:13 -0700
commit59df1c2bdecb0d1aaadfb8533df4bea528ee4952 (patch)
treeded1e05c84622331dd6a61b24db31e9b920f6970 /Documentation/firmware-guide/acpi/dsd/data-node-references.rst
parentc620f7bd0ba5c882b3e7fc199a8d5c2f6c2f5263 (diff)
parent10b4768b27a0b8f9459570723ecb1809f4d707e0 (diff)
Merge tag 'acpi-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI updates from Rafael Wysocki: "These rearrange the ACPI documentation by converting it to the .rst format and splitting it into clear categories (admin guide, driver API, firmware guide), switch over multiple users of a problematic library function to a new better one, update the ACPICA code in the kernel to a new upstream release, fix a few issues, improve power device management diagnostics and do some cleanups. Specifics: - Convert the ACPI documentation in the kernel source tree to the .rst format and split it into the admin guide, driver API and firmware guide parts (Changbin Du). - Add a PRP0001 usage example to the ACPI documentation (Thomas Preston). - Switch over the users of the acpi_dev_get_first_match_name() library function which turned out to be problematic to a new, better one called acpi_dev_get_first_match_dev() (Andy Shevchenko, YueHaibing). - Update the ACPICA code in the kernel to upstream release 20190405 including: * Null pointer dereference check in acpi_ns_delete_node() (Erik Schmauss). * Multiple macro and function name changes (Bob Moore). * Predefined operation region name fix (Erik Schmauss). - Fix hibernation issue on systems using the Baytrail and Cherrytrail Intel SoCs introduced during the 4.20 development cycle (Hans de Goede). - Add Sony VPCEH3U1E to the backlight quirk list (Zhang Rui). - Fix button handling during system resume (Zhang Rui). - Add a device PM diagnostic message (Rafael Wysocki). - Clean up the code, comments and white space in multiple places (Bjorn Helgaas, Gustavo Silva, Kefeng Wang)" * tag 'acpi-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (53 commits) Documentation: ACPI: move video_extension.txt to firmware-guide/acpi and convert to reST Documentation: ACPI: move ssdt-overlays.txt to admin-guide/acpi and convert to reST Documentation: ACPI: move lpit.txt to firmware-guide/acpi and convert to reST Documentation: ACPI: move cppc_sysfs.txt to admin-guide/acpi and convert to reST Documentation: ACPI: move apei/einj.txt to firmware-guide/acpi and convert to reST Documentation: ACPI: move apei/output_format.txt to firmware-guide/acpi and convert to reST Documentation: ACPI: move aml-debugger.txt to firmware-guide/acpi and convert to reST Documentation: ACPI: move method-tracing.txt to firmware-guide/acpi and convert to rsST Documentation: ACPI: move debug.txt to firmware-guide/acpi and convert to reST Documentation: ACPI: move dsd/data-node-references.txt to firmware-guide/acpi and convert to reST Documentation: ACPI: move dsd/graph.txt to firmware-guide/acpi and convert to reST Documentation: ACPI: move acpi-lid.txt to firmware-guide/acpi and convert to reST Documentation: ACPI: move i2c-muxes.txt to firmware-guide/acpi and convert to reST Documentation: ACPI: move dsdt-override.txt to admin-guide/acpi and convert to reST Documentation: ACPI: move initrd_table_override.txt to admin-guide/acpi and convert to reST Documentation: ACPI: move method-customizing.txt to firmware-guide/acpi and convert to reST Documentation: ACPI: move gpio-properties.txt to firmware-guide/acpi and convert to reST Documentation: ACPI: move DSD-properties-rules.txt to firmware-guide/acpi and covert to reST Documentation: ACPI: move scan_handlers.txt to driver-api/acpi and convert to reST Documentation: ACPI: move linuxized-acpica.txt to driver-api/acpi and convert to reST ...
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+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
+
+===================================
+Referencing hierarchical data nodes
+===================================
+
+:Copyright: |copy| 2018 Intel Corporation
+:Author: Sakari Ailus <sakari.ailus@linux.intel.com>
+
+ACPI in general allows referring to device objects in the tree only.
+Hierarchical data extension nodes may not be referred to directly, hence this
+document defines a scheme to implement such references.
+
+A reference consist of the device object name followed by one or more
+hierarchical data extension [1] keys. Specifically, the hierarchical data
+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@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@0", NOD0 },
+ Package () { "node@1", NOD1 },
+ }
+ })
+ Name (NOD0, Package() {
+ ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+ Package () {
+ Package () { "random-property", 3 },
+ }
+ })
+ Name (NOD1, Package() {
+ ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
+ Package () {
+ Package () { "anothernode", ANOD },
+ }
+ })
+ Name (ANOD, Package() {
+ ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+ Package () {
+ Package () { "random-property", 0 },
+ }
+ })
+ }
+
+ Device (DEV1)
+ {
+ Name (_DSD, Package () {
+ ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+ Package () {
+ Package () { "reference", ^DEV0, "node@1", "anothernode" },
+ }
+ })
+ }
+
+Please also see a graph example in :doc:`graph`.
+
+References
+==========
+
+[1] Hierarchical Data Extension UUID For _DSD.
+<http://www.uefi.org/sites/default/files/resources/_DSD-hierarchical-data-extension-UUID-v1.1.pdf>,
+referenced 2018-07-17.
+
+[2] Device Properties UUID For _DSD.
+<http://www.uefi.org/sites/default/files/resources/_DSD-device-properties-UUID.pdf>,
+referenced 2016-10-04.