On 6/6/2023 11:35 AM, Jose Marinho wrote: > This patch clarifies that both Armv8 and v9 are in scope, not > just Armv8 systems. > Also, ARM is re-written as Arm. > > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > Cc: Jeremy Linton <Jeremy.Linton@xxxxxxx> > Cc: James Morse <James.Morse@xxxxxxx> > Cc: Rob Herring <Rob.Herring@xxxxxxx> > Cc: Will Deacon <will@xxxxxxxxxx> > Cc: Jonathan Corbet <corbet@xxxxxxx> > Cc: Hanjun Guo <guohanjun@xxxxxxxxxx> > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > Cc: linux-doc@xxxxxxxxxxxxxxx > Cc: linux-acpi@xxxxxxxxxxxxxxx > > Signed-off-by: Jose Marinho <jose.marinho@xxxxxxx> > Reviewed-by: Samer El-Haj-Mahmoud <Samer.El-Haj-Mahmoud@xxxxxxx> > --- > Documentation/arm64/arm-acpi.rst | 41 ++++++++++++++++---------------- > 1 file changed, 21 insertions(+), 20 deletions(-) > > diff --git a/Documentation/arm64/arm-acpi.rst b/Documentation/arm64/arm-acpi.rst > index 47ecb9930dde..1cafe38fc7f9 100644 > --- a/Documentation/arm64/arm-acpi.rst > +++ b/Documentation/arm64/arm-acpi.rst > @@ -1,40 +1,41 @@ > -===================== > -ACPI on ARMv8 Servers > -===================== > +=================== > +ACPI on Arm systems > +=================== > > -ACPI can be used for ARMv8 general purpose servers designed to follow > -the ARM SBSA (Server Base System Architecture) [0] and SBBR (Server > +ACPI can be used for Armv8 and Armv9 systems designed to follow > +the Arm SBSA (Server Base System Architecture) [0] and SBBR (Server > Base Boot Requirements) [1] specifications. Please note that the SBBR > can be retrieved simply by visiting [1], but the SBSA is currently only > available to those with an ARM login due to ARM IP licensing concerns. > > -The ARMv8 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 > it refers to are managed by the UEFI Forum. The specification is > available at http://www.uefi.org/specifications and documents referenced > by the specification can be found via http://www.uefi.org/acpi. > > -If an ARMv8 system does not meet the requirements of the SBSA and SBBR, > +If an Arm system does not meet the requirements of the BSA and BBR, > or cannot be described using the mechanisms defined in the required ACPI > specifications, then ACPI may not be a good fit for the hardware. > > While the documents mentioned above set out the requirements for building > -industry-standard ARMv8 servers, they also apply to more than one operating > +industry-standard Arm systems, they also apply to more than one operating > system. The purpose of this document is to describe the interaction between > -ACPI and Linux only, on an ARMv8 system -- that is, what Linux expects of > +ACPI and Linux only, on an Arm system -- that is, what Linux expects of > ACPI and what ACPI can expect of Linux. > > > -Why ACPI on ARM? > +Why ACPI on Arm? > ---------------- > Before examining the details of the interface between ACPI and Linux, it is > useful to understand why ACPI is being used. Several technologies already > 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 > -reasoning behind ACPI on ARMv8 servers. 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. > > -The short form of the rationale for ACPI on ARM is: > +The short form of the rationale for ACPI on Arm is: > > - ACPI’s byte code (AML) allows the platform to encode hardware behavior, > while DT explicitly does not support this. For hardware vendors, being > @@ -47,7 +48,7 @@ The short form of the rationale for ACPI on ARM is: > > - In the enterprise server environment, ACPI has established bindings (such > as for RAS) which are currently used in production systems. DT does not. > - Such bindings could be defined in DT at some point, but doing so means ARM > + Such bindings could be defined in DT at some point, but doing so means Arm > and x86 would end up using completely different code paths in both firmware > and the kernel. > > @@ -108,7 +109,7 @@ recent version of the kernel. > > Relationship with Device Tree > ----------------------------- > -ACPI support in drivers and subsystems for ARMv8 should never be mutually > +ACPI support in drivers and subsystems for Arm should never be mutually > exclusive with DT support at compile time. > > At boot time the kernel will only use one description method depending on > @@ -121,11 +122,11 @@ time). > > Booting using ACPI tables > ------------------------- > -The only defined method for passing ACPI tables to the kernel on ARMv8 > +The only defined method for passing ACPI tables to the kernel on Arm > is via the UEFI system configuration table. Just so it is explicit, this > means that ACPI is only supported on platforms that boot via UEFI. > > -When an ARMv8 system boots, it can either have DT information, ACPI tables, > +When an Arm system boots, it can either have DT information, ACPI tables, > or in some very unusual cases, both. If no command line parameters are used, > the kernel will try to use DT for device enumeration; if there is no DT > present, the kernel will try to use ACPI tables, but only if they are present. > @@ -448,7 +449,7 @@ ASWG > ---- > The ACPI specification changes regularly. During the year 2014, for instance, > version 5.1 was released and version 6.0 substantially completed, with most of > -the changes being driven by ARM-specific requirements. Proposed changes are > +the changes being driven by Arm-specific requirements. Proposed changes are > presented and discussed in the ASWG (ACPI Specification Working Group) which > is a part of the UEFI Forum. The current version of the ACPI specification > is 6.1 release in January 2016. > @@ -456,7 +457,7 @@ is 6.1 release in January 2016. > Participation in this group is open to all UEFI members. Please see > http://www.uefi.org/workinggroup for details on group membership. Not part of this patch, but while at it maybe fix the http://www.uefi.org/workinggroup that doesn't work - it returns 404. > > -It is the intent of the ARMv8 ACPI kernel code to follow the ACPI specification > +It is the intent of the Arm ACPI kernel code to follow the ACPI specification > as closely as possible, and to only implement functionality that complies with > the released standards from UEFI ASWG. As a practical matter, there will be > vendors that provide bad ACPI tables or violate the standards in some way. > @@ -470,12 +471,12 @@ likely be willing to assist in submitting ECRs. > > Linux Code > ---------- > -Individual items specific to Linux on ARM, contained in the Linux > +Individual items specific to Linux on Arm, contained in the Linux > source code, are in the list that follows: > > ACPI_OS_NAME > This macro defines the string to be returned when > - an ACPI method invokes the _OS method. On ARM64 > + an ACPI method invokes the _OS method. On Arm64 > systems, this macro will be "Linux" by default. > The command line parameter acpi_os=<string> > can be used to set it to some other value. The
