Commit 8c350dfc authored by Jose Marinho's avatar Jose Marinho Committed by Catalin Marinas

Documentation/arm64: Update references in arm-acpi

This patch:
- Updates the reference to the DSD document,
- Removes the unused reference to AMD Seattle,
- Updates the references to BBR, BSA and SBSA.

Cc: Jeremy Linton <Jeremy.Linton@arm.com>
Cc: James Morse <James.Morse@arm.com>
Cc: Rob Herring <Rob.Herring@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-doc@vger.kernel.org
Cc: linux-acpi@vger.kernel.org
Signed-off-by: default avatarJose Marinho <jose.marinho@arm.com>
Reviewed-by: default avatarSamer El-Haj-Mahmoud <Samer.El-Haj-Mahmoud@arm.com>
Reviewed-by: default avatarRobin Murphy <robin.murphy@arm.com>
Acked-by: default avatarSudeep Holla <sudeep.holla@arm.com>
Reviewed-by: default avatarJeremy Linton <jeremy.linton@arm.com>
Reviewed-by: default avatarHanjun Guo <guohanjun@huawei.com>
Link: https://lore.kernel.org/r/20230606093528.1494344-3-jose.marinho@arm.comSigned-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 137477c8
...@@ -3,11 +3,11 @@ ACPI on Arm systems ...@@ -3,11 +3,11 @@ ACPI on Arm systems
=================== ===================
ACPI can be used for Armv8 and Armv9 systems designed to follow ACPI can be used for Armv8 and Armv9 systems designed to follow
the Arm SBSA (Server Base System Architecture) [0] and SBBR (Server the BSA (Arm Base System Architecture) [0] and BBR (Arm
Base Boot Requirements) [1] specifications. Please note that the SBBR Base Boot Requirements) [1] specifications. Both BSA and BBR are publicly
can be retrieved simply by visiting [1], but the SBSA is currently only accessible documents.
available to those with an ARM login due to ARM IP licensing concerns. Arm Servers, in addition to being BSA compliant, comply with a set
of rules defined in SBSA (Server Base System Architecture) [2].
The Arm kernel implements the reduced hardware model of ACPI version The Arm kernel implements the reduced hardware model of ACPI version
5.1 or later. Links to the specification and all external documents 5.1 or later. Links to the specification and all external documents
...@@ -31,7 +31,7 @@ Why ACPI on Arm? ...@@ -31,7 +31,7 @@ Why ACPI on Arm?
Before examining the details of the interface between ACPI and Linux, it is Before examining the details of the interface between ACPI and Linux, it is
useful to understand why ACPI is being used. Several technologies already useful to understand why ACPI is being used. Several technologies already
exist in Linux for describing non-enumerable hardware, after all. In this exist in Linux for describing non-enumerable hardware, after all. In this
section we summarize a blog post [2] from Grant Likely that outlines the section we summarize a blog post [3] from Grant Likely that outlines the
reasoning behind ACPI on Arm systems. Actually, we snitch a good portion reasoning behind ACPI on Arm systems. Actually, we snitch a good portion
of the summary text almost directly, to be honest. of the summary text almost directly, to be honest.
...@@ -270,16 +270,14 @@ Drivers should look for device properties in the _DSD object ONLY; the _DSD ...@@ -270,16 +270,14 @@ Drivers should look for device properties in the _DSD object ONLY; the _DSD
object is described in the ACPI specification section 6.2.5, but this only object is described in the ACPI specification section 6.2.5, but this only
describes how to define the structure of an object returned via _DSD, and describes how to define the structure of an object returned via _DSD, and
how specific data structures are defined by specific UUIDs. Linux should how specific data structures are defined by specific UUIDs. Linux should
only use the _DSD Device Properties UUID [5]: only use the _DSD Device Properties UUID [4]:
- UUID: daffd814-6eba-4d8c-8a91-bc9bbf4aa301 - UUID: daffd814-6eba-4d8c-8a91-bc9bbf4aa301
- https://www.uefi.org/sites/default/files/resources/_DSD-device-properties-UUID.pdf Common device properties can be registered by creating a pull request to [4] so
that they may be used across all operating systems supporting ACPI.
The UEFI Forum provides a mechanism for registering device properties [4] Device properties that have not been registered with the UEFI Forum can be used
so that they may be used across all operating systems supporting ACPI. but not as "uefi-" common properties.
Device properties that have not been registered with the UEFI Forum should
not be used.
Before creating new device properties, check to be sure that they have not Before creating new device properties, check to be sure that they have not
been defined before and either registered in the Linux kernel documentation been defined before and either registered in the Linux kernel documentation
...@@ -307,7 +305,7 @@ process. ...@@ -307,7 +305,7 @@ process.
Once registration and review have been completed, the kernel provides an Once registration and review have been completed, the kernel provides an
interface for looking up device properties in a manner independent of interface for looking up device properties in a manner independent of
whether DT or ACPI is being used. This API should be used [6]; it can whether DT or ACPI is being used. This API should be used [5]; it can
eliminate some duplication of code paths in driver probing functions and eliminate some duplication of code paths in driver probing functions and
discourage divergence between DT bindings and ACPI device properties. discourage divergence between DT bindings and ACPI device properties.
...@@ -491,31 +489,23 @@ Documentation/arm64/acpi_object_usage.rst. ...@@ -491,31 +489,23 @@ Documentation/arm64/acpi_object_usage.rst.
References References
---------- ----------
[0] http://silver.arm.com [0] https://developer.arm.com/documentation/den0094/latest
document ARM-DEN-0029, or newer: document Arm-DEN-0094: "Arm Base System Architecture", version 1.0C, dated 6 Oct 2022
"Server Base System Architecture", version 2.3, dated 27 Mar 2014
[1] https://developer.arm.com/documentation/den0044/latest
Document Arm-DEN-0044: "Arm Base Boot Requirements", version 2.0G, dated 15 Apr 2022
[1] http://infocenter.arm.com/help/topic/com.arm.doc.den0044a/Server_Base_Boot_Requirements.pdf [2] https://developer.arm.com/documentation/den0029/latest
Document ARM-DEN-0044A, or newer: "Server Base Boot Requirements, System Document Arm-DEN-0029: "Arm Server Base System Architecture", version 7.1, dated 06 Oct 2022
Software on ARM Platforms", dated 16 Aug 2014
[2] http://www.secretlab.ca/archives/151, [3] http://www.secretlab.ca/archives/151,
10 Jan 2015, Copyright (c) 2015, 10 Jan 2015, Copyright (c) 2015,
Linaro Ltd., written by Grant Likely. Linaro Ltd., written by Grant Likely.
[3] AMD ACPI for Seattle platform documentation [4] _DSD (Device Specific Data) Implementation Guide
http://amd-dev.wpengine.netdna-cdn.com/wordpress/media/2012/10/Seattle_ACPI_Guide.pdf https://github.com/UEFI/DSD-Guide/blob/main/dsd-guide.pdf
[4] http://www.uefi.org/acpi
please see the link for the "ACPI _DSD Device
Property Registry Instructions"
[5] http://www.uefi.org/acpi
please see the link for the "_DSD (Device
Specific Data) Implementation Guide"
[6] Kernel code for the unified device [5] Kernel code for the unified device
property interface can be found in property interface can be found in
include/linux/property.h and drivers/base/property.c. include/linux/property.h and drivers/base/property.c.
......
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