Re: [RESEND PATCH v2] ARM64: ACPI: Update documentation for latest specification version

From: Catalin Marinas
Date: Fri Mar 18 2016 - 08:30:26 EST

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On Wed, Mar 16, 2016 at 10:20:23AM +0530, Vikas Sajjan wrote:
> On Wed, Mar 16, 2016 at 1:58 AM, Al Stone <al.stone@xxxxxxxxxx> wrote:
> > The ACPI 6.1 specification was recently released at the end of January 2016,
> > but the arm64 kernel documentation for the use of ACPI was written for the
> > 5.1 version of the spec. There were significant additions to the spec that
> > had not yet been mentioned -- for example, the 6.0 mechanisms added to make
> > it easier to define processors and low power idle states, as well as the
> > 6.1 addition allowing regular interrupts (not just from GPIO) be used to
> > signal ACPI general purpose events.
> >
> > This patch reflects going back through and examining the specs in detail
> > and updating content appropriately. Whilst there, a few odds and ends of
> > typos were caught as well. This brings the documentation up to date with
> > ACPI 6.1 for arm64.
> >
> > RESEND:
> > -- Corrected From: header and added missing Cc's
> >
> > Changes for v2:
> > -- Clean up white space (Harb Abdulhahmid)
> > -- Clarification on _CCA usage (Harb Abdulhamid)
> > -- IORT moved to required from recommended (Hanjun Guo)
> > -- Clarify IORT description (Hanjun Guo)
> >
> > Signed-off-by: Al Stone <al.stone@xxxxxxxxxx>
> > Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> > Cc: Will Deacon <will.deacon@xxxxxxx>
> > Cc: Jonathan Corbet <corbet@xxxxxxx>
> > ---
> > Documentation/arm64/acpi_object_usage.txt | 445 ++++++++++++++++++++++--------
> > Documentation/arm64/arm-acpi.txt | 28 +-
> > 2 files changed, 356 insertions(+), 117 deletions(-)
> >
> > diff --git a/Documentation/arm64/acpi_object_usage.txt b/Documentation/arm64/acpi_object_usage.txt
> > index a6e1a18..29bc1a1 100644
> > --- a/Documentation/arm64/acpi_object_usage.txt
> > +++ b/Documentation/arm64/acpi_object_usage.txt
> > @@ -11,15 +11,16 @@ outside of the UEFI Forum (see Section 5.2.6 of the specification).
> >
> > For ACPI on arm64, tables also fall into the following categories:
> >
> > - -- Required: DSDT, FADT, GTDT, MADT, MCFG, RSDP, SPCR, XSDT
> > + -- Required: DSDT, FADT, GTDT, IORT, MADT, MCFG, RSDP, SPCR, XSDT
> >
> > - -- Recommended: BERT, EINJ, ERST, HEST, SSDT
> > + -- Recommended: BERT, EINJ, ERST, HEST, PCCT, SSDT
> >
> > - -- Optional: BGRT, CPEP, CSRT, DRTM, ECDT, FACS, FPDT, MCHI, MPST,
> > - MSCT, RASF, SBST, SLIT, SPMI, SRAT, TCPA, TPM2, UEFI
> > + -- Optional: BGRT, CPEP, CSRT, DBG2, DRTM, ECDT, FACS, FPDT, MCHI,
> > + MPST, MSCT, NFIT, PMTT, RASF, SBST, SLIT, SPMI, SRAT, STAO, TCPA,
> > + TPM2, UEFI, XENV
> >
> > - -- Not supported: BOOT, DBG2, DBGP, DMAR, ETDT, HPET, IBFT, IVRS,
> > - LPIT, MSDM, RSDT, SLIC, WAET, WDAT, WDRT, WPBT
> > + -- Not supported: BOOT, DBGP, DMAR, ETDT, HPET, IBFT, IVRS, LPIT,
> > + MSDM, OEMx, PSDT, RSDT, SLIC, WAET, WDAT, WDRT, WPBT
> >
> >
> > Table Usage for ARMv8 Linux
> > @@ -50,7 +51,8 @@ CSRT Signature Reserved (signature == "CSRT")
> >
> > DBG2 Signature Reserved (signature == "DBG2")
> > == DeBuG port table 2 ==
> > - Microsoft only table, will not be supported.
> > + License has changed and should be usable. Optional if used instead
> > + of earlycon=<device> on the command line.
> >
> > DBGP Signature Reserved (signature == "DBGP")
> > == DeBuG Port table ==
> > @@ -133,10 +135,11 @@ GTDT Section 5.2.24 (signature == "GTDT")
> >
> > HEST Section 18.3.2 (signature == "HEST")
> > == Hardware Error Source Table ==
> > - Until further error source types are defined, use only types 6 (AER
> > - Root Port), 7 (AER Endpoint), 8 (AER Bridge), or 9 (Generic Hardware
> > - Error Source). Firmware first error handling is possible if and only
> > - if Trusted Firmware is being used on arm64.
> > + ARM-specific error sources have been defined; please use those or the
> > + PCI types such as type 6 (AER Root Port), 7 (AER Endpoint), or 8 (AER
> > + Bridge), or use type 9 (Generic Hardware Error Source). Firmware first
> > + error handling is possible if and only if Trusted Firmware is being
> > + used on arm64.
> >
> > Must be supplied if RAS support is provided by the platform. It
> > is recommended this table be supplied.
> > @@ -149,20 +152,27 @@ IBFT Signature Reserved (signature == "IBFT")
> > == iSCSI Boot Firmware Table ==
> > Microsoft defined table, support TBD.
> >
> > +IORT Signature Reserved (signature == "IORT")
> > + == Input Output Remapping Table ==
> > + arm64 only table, required in order to describe IO topology, SMMUs,
> > + and GIC ITSs, and how those various components are connected together,
> > + such as identifying which components are behind which SMMUs/ITSs.
> > +
> > IVRS Signature Reserved (signature == "IVRS")
> > == I/O Virtualization Reporting Structure ==
> > x86_64 (AMD) only table, will not be supported.
> >
> > LPIT Signature Reserved (signature == "LPIT")
> > == Low Power Idle Table ==
> > - x86 only table as of ACPI 5.1; future versions have been adapted for
> > - use with ARM and will be recommended in order to support ACPI power
> > - management.
> > + x86 only table as of ACPI 5.1; starting with ACPI 6.0, processor
> > + descriptions and power states on ARM platforms should use the DSDT
> > + and define processor container devices (_HID ACPI0010, Section 8.4,
> > + and more specifically 8.4.3 and and 8.4.4).
> >
> > MADT Section 5.2.12 (signature == "APIC")
> > == Multiple APIC Description Table ==
> > Required for arm64. Only the GIC interrupt controller structures
> > - should be used (types 0xA - 0xE).
> > + should be used (types 0xA - 0xF).
> >
> > MCFG Signature Reserved (signature == "MCFG")
> > == Memory-mapped ConFiGuration space ==
> > @@ -176,14 +186,38 @@ MPST Section 5.2.21 (signature == "MPST")
> > == Memory Power State Table ==
> > Optional, not currently supported.
> >
> > +MSCT Section 5.2.19 (signature == "MSCT")
> > + == Maximum System Characteristic Table ==
> > + Optional, not currently supported.
> > +
> > MSDM Signature Reserved (signature == "MSDM")
> > == Microsoft Data Management table ==
> > Microsoft only table, will not be supported.
> >
> > -MSCT Section 5.2.19 (signature == "MSCT")
> > - == Maximum System Characteristic Table ==
> > +NFIT Section 5.2.25 (signature == "NFIT")
> > + == NVDIMM Firmware Interface Table ==
> > Optional, not currently supported.
> >
> > +OEMx Signature of "OEMx" only
> > + == OEM Specific Tables ==
> > + All tables starting with a signature of "OEM" are reserved for OEM
> > + use. Since these are not meant to be of general use but are limited
> > + to very specific end users, they are not recommended for use and are
> > + not supported by the kernel for arm64.
> > +
> > +PCCT Section 14.1 (signature == "PCCT)
> > + == Platform Communications Channel Table ==
> > + Recommend for use on arm64, and required when using CPPC to control
> > + power on the platform.
> > +
> > +PMTT Section 5.2.21.12 (signature == "PMTT")
> > + == Platform Memory Topology Table ==
> > + Optional, but useful, but not currently supported.
> > +
> > +PSDT Section 5.2.11.3 (signature == "PSDT")
> > + == Persistent System Description Table ==
> > + Obsolete table, will not be supported.
> > +
> > RASF Section 5.2.20 (signature == "RASF")
> > == RAS Feature table ==
> > Optional, not currently supported.
> > @@ -195,7 +229,7 @@ RSDP Section 5.2.5 (signature == "RSD PTR")
> > RSDT Section 5.2.7 (signature == "RSDT")
> > == Root System Description Table ==
> > Since this table can only provide 32-bit addresses, it is deprecated
> > - on arm64, and will not be used.
> > + on arm64, and will not be used. If provided, it will be ignored.
> >
> > SBST Section 5.2.14 (signature == "SBST")
> > == Smart Battery Subsystem Table ==
> > @@ -207,7 +241,7 @@ SLIC Signature Reserved (signature == "SLIC")
> >
> > SLIT Section 5.2.17 (signature == "SLIT")
> > == System Locality distance Information Table ==
> > - Optional in general, but required for NUMA systems.
> > + Optional in general, but required for arm64 NUMA systems.
> >
> > SPCR Signature Reserved (signature == "SPCR")
> > == Serial Port Console Redirection table ==
> > @@ -220,7 +254,7 @@ SPMI Signature Reserved (signature == "SPMI")
> > SRAT Section 5.2.16 (signature == "SRAT")
> > == System Resource Affinity Table ==
> > Optional, but if used, only the GICC Affinity structures are read.
> > - To support NUMA, this table is required.
> > + To support arm64 NUMA, this table is required.
> >
> > SSDT Section 5.2.11.2 (signature == "SSDT")
> > == Secondary System Description Table ==
> > @@ -235,6 +269,11 @@ SSDT Section 5.2.11.2 (signature == "SSDT")
> > These tables are optional, however. ACPI tables should contain only
> > one DSDT but can contain many SSDTs.
> >
> > +STAO Signature Reserved (signature == "STAO")
> > + == _STA Override table ==
> > + Optional, but only necessary in virtualized environments in order to
> > + hide devices from guest OSs.
> > +
> > TCPA Signature Reserved (signature == "TCPA")
> > == Trusted Computing Platform Alliance table ==
> > Optional, not currently supported, and may need changes to fully
> > @@ -266,6 +305,10 @@ WPBT Signature Reserved (signature == "WPBT")
> > == Windows Platform Binary Table ==
> > Microsoft only table, will not be supported.
> >
> > +XENV Signature Reserved (signature == "XENV")
> > + == Xen project table ==
> > + Optional, used only by Xen at present.
> > +
> > XSDT Section 5.2.8 (signature == "XSDT")
> > == eXtended System Description Table ==
> > Required for arm64.
> > @@ -273,31 +316,57 @@ XSDT Section 5.2.8 (signature == "XSDT")
> >
> > ACPI Objects
> > ------------
> > -The expectations on individual ACPI objects are discussed in the list that
> > -follows:
> > +The expectations on individual ACPI objects that are likely to be used are
> > +shown in the list that follows:
> >
> > Name Section Usage for ARMv8 Linux
> > ---- ------------ -------------------------------------------------
> > +_ACx 11.4.1 Use as needed.
> > +
> > _ADR 6.1.1 Use as needed.
> >
> > +_ALx 11.4.2 Use as needed.
> > +
> > +_ART 11.4.3 Use as needed.
> > +
> > _BBN 6.5.5 Use as needed; PCI-specific.
> >
> > -_BDN 6.5.3 Optional; not likely to be used on arm64.
> > +_CCA 6.2.17 This method must be defined for all bus masters
> > + on arm64 -- there are no assumptions made about
> > + whether such devices are cache coherent or not.
> > + The _CCA value is inherited by all descendants of
> > + these devices so it does not need to be repeated.
> > + Without _CCA on arm64, the kernel does not know what
> > + to do about setting up DMA for the device.
> >
> > -_CCA 6.2.17 This method should be defined for all bus masters
> > - on arm64. While cache coherency is assumed, making
> > - it explicit ensures the kernel will set up DMA as
> > - it should.
> > + NB: this method provides default cache coherency
> > + attributes; the presence of an SMMU can be used to
> > + modify that, however. For example, a master could
> > + default to non-coherent, but be made coherent with
> > + the appropriate SMMU configuration (see Table 17 of
> > + the IORT specification, ARM Document DEN 0049B).
> >
> > -_CDM 6.2.1 Optional, to be used only for processor devices.
> > +_CDM 6.2.1 Use as needed, to be used only for processor devices.
> >
> > -_CID 6.1.2 Use as needed.
> > +_CID 6.1.2 Use as needed, see also _HID.
> >
> > -_CLS 6.1.3 Use as needed.
> > +_CLS 6.1.3 Use as needed, see also _HID.
> > +
> > +_CPC 8.4.7.1 Use as needed; power management specific. CPPC is
> > + recommended on arm64.
> > +
> > +_CR3 11.4.5 Use as needed.
> >
> > _CRS 6.2.2 Required on arm64.
> >
> > -_DCK 6.5.2 Optional; not likely to be used on arm64.
> > +_CRT 11.4.4 Use as needed.
> > +
> > +_CSD 8.4.2.2 Use as needed, used only in conjuction with _CST.
> > +
> > +_CST 8.4.2.1 Low power idle states (8.4.4) are recommended instead
> > + of C-states.
> > +
> > +_CWS 9.18.6 Use as needed.
> >
> > _DDN 6.1.4 This field can be used for a device name. However,
> > it is meant for DOS device names (e.g., COM1), so be
> > @@ -305,11 +374,11 @@ _DDN 6.1.4 This field can be used for a device name. However,
> >
> > _DEP 6.5.8 Use as needed.
> >
> > -_DIS 6.2.3 Optional, for power management use.
> > +_DIS 6.2.3 Use as needed, for power management use.
> >
> > -_DLM 5.7.5 Optional.
> > +_DLM 5.7.5 Use as needed.
> >
> > -_DMA 6.2.4 Optional.
> > +_DMA 6.2.4 Use as needed.
> >
> > _DSD 6.2.5 To be used with caution. If this object is used, try
> > to use it within the constraints already defined by the
> > @@ -325,19 +394,29 @@ _DSD 6.2.5 To be used with caution. If this object is used, try
> > with the UEFI Forum; this may cause some iteration as
> > more than one OS will be registering entries.
> >
> > -_DSM Do not use this method. It is not standardized, the
> > +_DSM 9.1.1 Do not use this method. It is not standardized, the
> > return values are not well documented, and it is
> > currently a frequent source of error.
> >
> > -_DSW 7.2.1 Use as needed; power management specific.
> > +_DSW 7.3.1 Use as needed; power management specific.
> >
> > -_EDL 6.3.1 Optional.
> > +_DTI 11.4.6 Use as needed.
> >
> > -_EJD 6.3.2 Optional.
> > +_EDL 6.3.1 Use as needed.
> >
> > -_EJx 6.3.3 Optional.
> > +_EJD 6.3.2 Use as needed.
> >
> > -_FIX 6.2.7 x86 specific, not used on arm64.
> > +_EJx 6.3.3 Use as needed.
> > +
> > +_FIF 11.3.1.1 Use as needed.
> > +
> > +_FPS 11.3.1.2 Use as needed.
> > +
> > +_FSL 11.3.1.3 Use as needed.
> > +
> > +_FST 11.3.1.4 Use as needed.
> > +
> > +_GCP 9.18.2 Use as needed.
> >
> > \_GL 5.7.1 This object is not to be used in hardware reduced
> > mode, and therefore should not be used on arm64.
> > @@ -349,35 +428,57 @@ _GLK 6.5.7 This object requires a global lock be defined; there
> > \_GPE 5.3.1 This namespace is for x86 use only. Do not use it
> > on arm64.
> >
> > -_GSB 6.2.7 Optional.
> > +_GRT 9.18.3 Use as needed.
> > +
> > +_GSB 6.2.7 Use as needed.
> > +
> > +_GTF 9.9.1.1 Use as needed.
> > +
> > +_GWS 9.18.5 Use as needed.
> >
> > _HID 6.1.5 Use as needed. This is the primary object to use in
> > device probing, though _CID and _CLS may also be used.
> >
> > -_HPP 6.2.8 Optional, PCI specific.
> > +_HOT 11.4.7 Use as needed.
> > +
> > +_HPP 6.2.8 Use as needed, PCI specific.
> >
> > -_HPX 6.2.9 Optional, PCI specific.
> > +_HPX 6.2.9 Use as needed, PCI specific.
> >
> > -_HRV 6.1.6 Optional, use as needed to clarify device behavior; in
> > - some cases, this may be easier to use than _DSD.
> > +_HRV 6.1.6 Use as needed, use as needed to clarify device
> > + behavior; in some cases, this may be easier to use
> > + than _DSD.
> >
> > _INI 6.5.1 Not required, but can be useful in setting up devices
> > when UEFI leaves them in a state that may not be what
> > the driver expects before it starts probing.
> >
> > -_IRC 7.2.15 Use as needed; power management specific.
> > +_IRC 7.3.15 Use as needed; power management specific.
> > +
> > +_LCK 6.3.4 Use as needed.
> > +
> > +_LPI 8.4.4.3 Use as needed, but recommended for use with processor
> > + definitions (_HID ACPI0010) on arm64.
> >
> > -_LCK 6.3.4 Optional.
> > +_MAT 6.2.10 Use as needed; see also the MADT.
> >
> > -_MAT 6.2.10 Optional; see also the MADT.
> > +_MBM 9.13.2.1 Use as needed.
> >
> > -_MLS 6.1.7 Optional, but highly recommended for use in
> > +_MLS 6.1.7 Use as needed, but highly recommended for use in
> > internationalization.
> >
> > -_OFF 7.1.2 It is recommended to define this method for any device
> > +_MSG 9.2.2 Use as needed.
> > +
> > +_MSM 9.13.2.2 Use as needed.
> > +
> > +_MTL 11.4.8 Use as needed.
> > +
> > +_NTT 11.4.9 Use as needed.
> > +
> > +_OFF 7.2.2 It is recommended to define this method for any device
> > that can be turned on or off.
> >
> > -_ON 7.1.3 It is recommended to define this method for any device
> > +_ON 7.2.3 It is recommended to define this method for any device
> > that can be turned on or off.
> >
> > \_OS 5.7.3 This method will return "Linux" by default (this is
> > @@ -405,115 +506,219 @@ _OSC 6.2.11 This method can be a global method in ACPI (i.e.,
> > being used or what functionality is provided. The
> > _OSC method is to be used instead.
> >
> > -_OST 6.3.5 Optional.
> > +_OST 6.3.5 Use as needed.
> > +
> > +_PCT 8.4.6.1 Use as needed; power management specific.
> >
> > _PDC 8.4.1 Deprecated, do not use on arm64.
> >
> > +_PDL 8.4.6.2 Use as needed; power management specific.
> > +
> > \_PIC 5.8.1 The method should not be used. On arm64, the only
> > interrupt model available is GIC.
> >
> > -_PLD 6.1.8 Optional.
> > +_PLD 6.1.8 Use as needed.
> > +
> > +_PPC 8.4.6.3 Use as needed; power management specific.
> > +
> > +_PPE 8.4.8 Use as needed.
> >
> > \_PR 5.3.1 This namespace is for x86 use only on legacy systems.
> > Do not use it on arm64.
> >
> > -_PRS 6.2.12 Optional.
> > +_PRE 7.3.12 Use as needed; power management specific.
> > +
> > +_PRR 7.3.26 Use as needed; power management specific.
> > +
> > +_PRS 6.2.12 Use as needed.
> >
> > _PRT 6.2.13 Required as part of the definition of all PCI root
> > devices.
> >
> > -_PRW 7.2.13 Use as needed; power management specific.
> > +_PRW 7.3.13 Use as needed; power management specific.
> >
> > -_PRx 7.2.8-11 Use as needed; power management specific. If _PR0 is
> > +_PRx 7.3.8-11 Use as needed; power management specific. If _PR0 is
> > defined, _PR3 must also be defined.
> >
> > -_PSC 7.2.6 Use as needed; power management specific.
> > +_PSC 7.3.6 Use as needed; power management specific.
> > +
> > +_PSD 8.4.6.5 Use as needed; power management specific.
> >
> > -_PSE 7.2.7 Use as needed; power management specific.
> > +_PSE 7.3.7 Use as needed; power management specific.
> >
> > -_PSW 7.2.14 Use as needed; power management specific.
> > +_PSL 11.4.10 Use as needed.
> >
> > -_PSx 7.2.2-5 Use as needed; power management specific. If _PS0 is
> > +_PSS 8.4.6.2 Use as needed; power management specific.
> > +
> > +_PSV 11.4.11 Use as needed.
> > +
> > +_PSW 7.3.14 Use as needed; power management specific.
> > +
> > +_PSx 7.3.2-5 Use as needed; power management specific. If _PS0 is
> > defined, _PS3 must also be defined. If clocks or
> > regulators need adjusting to be consistent with power
> > usage, change them in these methods.
> >
> > -\_PTS 7.3.1 Use as needed; power management specific.
> > +_PTC 8.4.5.1 Use as needed; power management specific.
> > +
> > +\_PTS 7.4.1 Use as needed; power management specific.
> > +
> > +_PUR 8.5.1.1 Use as needed.
> > +
> > +_PXM 6.2.14 Use as needed.
> >
> > -_PXM 6.2.14 Optional.
> > +_RDI 8.4.4.4 Use as needed, but recommended for use with processor
> > + definitions (_HID ACPI0010) on arm64.
> >
>
> Should we also mention here that _RDI used only in conjuction with _LPI.
>
> Because as per section 8.4.4.4 "The dependency between the power
> resources and the LPI state is described in _RDI"
>
> > _REG 6.5.4 Use as needed.
> >
> > \_REV 5.7.4 Always returns the latest version of ACPI supported.
> >
> > -_RMV 6.3.6 Optional.
> > +_RMV 6.3.6 Use as needed.
> > +
> > +_RST 7.3.25 Use as needed; power management specific.
> > +
> > +_RTV 11.4.12 Use as needed.
> >
> > \_SB 5.3.1 Required on arm64; all devices must be defined in this
> > namespace.
> >
> > +_SCP 11.4.13 Use as needed.
> > +
> > +_SDD 9.9.3.3.1 Use as needed.
> > +
> > _SEG 6.5.6 Use as needed; PCI-specific.
> >
> > -\_SI 5.3.1, Optional.
> > - 9.1
> > +\_SI 5.3.1, Use as needed.
> > + 9.2
> > +
> > +_SLI 6.2.15 Use as needed; recommended when SLIT table is in use.
> >
> > -_SLI 6.2.15 Optional; recommended when SLIT table is in use.
> > +_SRT 9.18.4 Use as needed.
> >
> > _STA 6.3.7, It is recommended to define this method for any device
> > - 7.1.4 that can be turned on or off.
> > + 7.2.4 that can be turned on or off. See also the STAO table
> > + that provides overrides to hide devices in virtualized
> > + environments.
> >
> > -_SRS 6.2.16 Optional; see also _PRS.
> > +_SRS 6.2.16 Use as needed; see also _PRS.
> > +
> > +_SST 9.2.1 Use as needed.
> >
> > _STR 6.1.10 Recommended for conveying device names to end users;
> > this is preferred over using _DDN.
> >
> > +_SST 9.2.1 Use as needed.
> > +
> > +_STP 9.18.7 Use as needed.
> > +
> > +_STV 9.18.8 Use as needed.
> > +
> > _SUB 6.1.9 Use as needed; _HID or _CID are preferred.
> >
> > -_SUN 6.1.11 Optional.
> > +_SUN 6.1.11 Use as needed, but recommended.
> >
> > -\_Sx 7.3.2 Use as needed; power management specific.
> > +\_Sx 7.4.2 Use as needed; power management specific.
> >
> > -_SxD 7.2.16-19 Use as needed; power management specific.
> > +_SxD 7.3.16-19 Use as needed; power management specific.
> >
> > -_SxW 7.2.20-24 Use as needed; power management specific.
> > +_SxW 7.3.20-24 Use as needed; power management specific.
> >
> > -_SWS 7.3.3 Use as needed; power management specific; this may
> > +_SWS 7.4.3 Use as needed; power management specific; this may
> > require specification changes for use on arm64.
> >
> > -\_TTS 7.3.4 Use as needed; power management specific.
> > +_TC1 11.4.14 Use as needed.
> > +
> > +_TC2 11.4.15 Use as needed.
> > +
> > +_TDL 8.4.5.5 Use as needed; power management specific.
> > +
> > +_TFP 11.4.16 Use as needed.
> > +
> > +_TIP 9.18.9 Use as needed.
> > +
> > +_TIV 9.18.10 Use as needed.
> > +
> > +_TMP 11.4.17 Use as needed.
> > +
> > +_TPC 8.4.5.3 Use as needed; power management specific.
> >
> > -\_TZ 5.3.1 Optional.
> > +_TPT 11.4.18 Use as needed.
> > +
> > +_TRT 11.4.19 Use as needed.
> > +
> > +_TSD 8.4.5.4 Use as needed; power management specific.
> > +
> > +_TSN 11.4.20 Use as needed.
> > +
> > +_TSP 11.4.21 Use as needed.
> > +
> > +_TSS 8.4.5.2 Use as needed; power management specific.
> > +
> > +_TST 11.4.22 Use as needed.
> > +
> > +\_TTS 7.4.4 Use as needed; power management specific.
> > +
> > +\_TZ 5.3.1 Use as needed.
> > +
> > +_TZD 11.4.23 Use as needed.
> > +
> > +_TZM 11.4.24 Use as needed.
> > +
> > +_TZP 11.4.25 Use as needed.
> >
> > _UID 6.1.12 Recommended for distinguishing devices of the same
> > class; define it if at all possible.
> >
> > -\_WAK 7.3.5 Use as needed; power management specific.
> > +_UPC 9.14 Use as needed.
> > +
> > +\_WAK 7.4.5 Use as needed; power management specific.
> > +
> > +
> >
> >
> > ACPI Event Model
> > ----------------
> > Do not use GPE block devices; these are not supported in the hardware reduced
> > profile used by arm64. Since there are no GPE blocks defined for use on ARM
> > -platforms, GPIO-signaled interrupts should be used for creating system events.
> > +platforms, ACPI events must be signaled differently.
> > +
> > +There are two options: GPIO-signaled interrupts (Section 5.6.5), and
> > +interrupt-signaled events (Section 5.6.9). Interrupt-signaled events are a
> > +new feature in the ACPI 6.1 specification. Either -- or both -- can be used
> > +on a given platform, and which to use may be dependent of limitations in any
> > +given SoC. If possible, interrupt-signaled events are recommended.
> >
> >
> > ACPI Processor Control
> > ----------------------
> > -Section 8 of the ACPI specification is currently undergoing change that
> > -should be completed in the 6.0 version of the specification. Processor
> > -performance control will be handled differently for arm64 at that point
> > -in time. Processor aggregator devices (section 8.5) will not be used,
> > -for example, but another similar mechanism instead.
> > -
> > -While UEFI constrains what we can say until the release of 6.0, it is
> > -recommended that CPPC (8.4.5) be used as the primary model. This will
> > -still be useful into the future. C-states and P-states will still be
> > -provided, but most of the current design work appears to favor CPPC.
> > +Section 8 of the ACPI specification changed significantly in version 6.0.
> > +Processors should now be defined as Device objects with _HID ACPI0007; do
> > +not use the deprecated Processor statement in ASL. All multiprocessor systems
> > +should also define a hierarchy of processors, done with Processor Container
> > +Devices (see Section 8.4.3.1, _HID ACPI0010); do not use processor aggregator
> > +devices (Section 8.5) to describe processor topology. Section 8.4 of the
> > +specification describes the semantics of these object definitions and how
> > +they interrelate.
> > +
> > +Most importantly, the processor hierarchy defined also defines the low power
> > +idle states that are available to the platform, along with the rules for
> > +determining which processors can be turned on or off and the circumstances
> > +that control that. Without this information, the processors will run in
> > +whatever power state they were left in by UEFI.
> > +
> > +Note too, that the processor Device objects defined and the entries in the
> > +MADT for GICs are expected to be in sychronization. The _UID of the Device
> > +object must correspond to processor IDs used in the MADT.
> > +
> > +It is recommended that CPPC (8.4.5) be used as the primary model for processor
> > +performance control on arm64. C-states and P-states may become available at
> > +some point in the future, but most current design work appears to favor CPPC.
> >
> > Further, it is essential that the ARMv8 SoC provide a fully functional
> > implementation of PSCI; this will be the only mechanism supported by ACPI
> > -to control CPU power state (including secondary CPU booting).
> > -
> > -More details will be provided on the release of the ACPI 6.0 specification.
> > +to control CPU power state. Booting of secondary CPUs may be possible using
> > +parking protocol, but only PSCI is to be used for ARM servers.
> >
> >
> > ACPI System Address Map Interfaces
> > @@ -535,21 +740,25 @@ used to indicate fatal errors that cannot be corrected, and require immediate
> > attention.
> >
> > Since there is no direct equivalent of the x86 SCI or NMI, arm64 handles
> > -these slightly differently. The SCI is handled as a normal GPIO-signaled
> > -interrupt; given that these are corrected (or correctable) errors being
> > -reported, this is sufficient. The NMI is emulated as the highest priority
> > -GPIO-signaled interrupt possible. This implies some caution must be used
> > -since there could be interrupts at higher privilege levels or even interrupts
> > -at the same priority as the emulated NMI. In Linux, this should not be the
> > -case but one should be aware it could happen.
> > +these slightly differently. The SCI is handled as a high priority interrupt;
> > +given that these are corrected (or correctable) errors being reported, this
> > +is sufficient. The NMI is emulated as the highest priority interrupt
> > +possible. This implies some caution must be used since there could be
> > +interrupts at higher privilege levels or even interrupts at the same priority
> > +as the emulated NMI. In Linux, this should not be the case but one should
> > +be aware it could happen.

Unrelated to the patch content or to your reply (which I couldn't find
even after scrolling up and down a few times): please trim the original
message and only quote the relevant text, it would make following a
discussion much easier.

(I haven't trimmed it either and I randomly placed my reply, just to
make a point)

> >
> >
> > ACPI Objects Not Supported on ARM64
> > -----------------------------------
> > While this may change in the future, there are several classes of objects
> > that can be defined, but are not currently of general interest to ARM servers.
> > +Some of these objects have x86 equivalents, and may actually make sense in ARM
> > +servers. However, there is either no hardware available at present, or there
> > +may not even be a non-ARM implementation yet. Hence, they are not currently
> > +supported.
> >
> > -These are not supported:
> > +The following classes of objects are not supported:
> >
> > -- Section 9.2: ambient light sensor devices
> >
> > @@ -571,16 +780,6 @@ These are not supported:
> >
> > -- Section 9.18: time and alarm devices (see 9.15)
> >
> > -
> > -ACPI Objects Not Yet Implemented
> > ---------------------------------
> > -While these objects have x86 equivalents, and they do make some sense in ARM
> > -servers, there is either no hardware available at present, or in some cases
> > -there may not yet be a non-ARM implementation. Hence, they are currently not
> > -implemented though that may change in the future.
> > -
> > -Not yet implemented are:
> > -
> > -- Section 10: power source and power meter devices
> >
> > -- Section 11: thermal management
> > @@ -589,5 +788,31 @@ Not yet implemented are:
> >
> > -- Section 13: SMBus interfaces
> >
> > - -- Section 17: NUMA support (prototypes have been submitted for
> > - review)
> > +
> > +This also mean that there is no support for the following objects:
> > +
> > +Name Section Name Section
> > +---- ------------ ---- ------------
> > +_ALC 9.3.4 _FDM 9.10.3
> > +_ALI 9.3.2 _FIX 6.2.7
> > +_ALP 9.3.6 _GAI 10.4.5
> > +_ALR 9.3.5 _GHL 10.4.7
> > +_ALT 9.3.3 _GTM 9.9.2.1.1
> > +_BCT 10.2.2.10 _LID 9.5.1
> > +_BDN 6.5.3 _PAI 10.4.4
> > +_BIF 10.2.2.1 _PCL 10.3.2
> > +_BIX 10.2.2.1 _PIF 10.3.3
> > +_BLT 9.2.3 _PMC 10.4.1
> > +_BMA 10.2.2.4 _PMD 10.4.8
> > +_BMC 10.2.2.12 _PMM 10.4.3
> > +_BMD 10.2.2.11 _PRL 10.3.4
> > +_BMS 10.2.2.5 _PSR 10.3.1
> > +_BST 10.2.2.6 _PTP 10.4.2
> > +_BTH 10.2.2.7 _SBS 10.1.3
> > +_BTM 10.2.2.9 _SHL 10.4.6
> > +_BTP 10.2.2.8 _STM 9.9.2.1.1
> > +_DCK 6.5.2 _UPD 9.16.1
> > +_EC 12.12 _UPP 9.16.2
> > +_FDE 9.10.1 _WPC 10.5.2
> > +_FDI 9.10.2 _WPP 10.5.3
> > +
> > diff --git a/Documentation/arm64/arm-acpi.txt b/Documentation/arm64/arm-acpi.txt
> > index 570a4f8..12381c1 100644
> > --- a/Documentation/arm64/arm-acpi.txt
> > +++ b/Documentation/arm64/arm-acpi.txt
> > @@ -57,11 +57,11 @@ The short form of the rationale for ACPI on ARM is:
> >
> > -- The new ACPI governance process works well and Linux is now at the same
> > table as hardware vendors and other OS vendors. In fact, there is no
> > - longer any reason to feel that ACPI is only belongs to Windows or that
> > + longer any reason to feel that ACPI only belongs to Windows or that
> > Linux is in any way secondary to Microsoft in this arena. The move of
> > ACPI governance into the UEFI forum has significantly opened up the
> > specification development process, and currently, a large portion of the
> > - changes being made to ACPI is being driven by Linux.
> > + changes being made to ACPI are being driven by Linux.
> >
> > Key to the use of ACPI is the support model. For servers in general, the
> > responsibility for hardware behaviour cannot solely be the domain of the
> > @@ -159,7 +159,7 @@ Further, the ACPI core will only use the 64-bit address fields in the FADT
> > (Fixed ACPI Description Table). Any 32-bit address fields in the FADT will
> > be ignored on arm64.
> >
> > -Hardware reduced mode (see Section 4.1 of the ACPI 5.1 specification) will
> > +Hardware reduced mode (see Section 4.1 of the ACPI 6.1 specification) will
> > be enforced by the ACPI core on arm64. Doing so allows the ACPI core to
> > run less complex code since it no longer has to provide support for legacy
> > hardware from other architectures. Any fields that are not to be used for
> > @@ -167,7 +167,7 @@ hardware reduced mode must be set to zero.
> >
> > For the ACPI core to operate properly, and in turn provide the information
> > the kernel needs to configure devices, it expects to find the following
> > -tables (all section numbers refer to the ACPI 5.1 specfication):
> > +tables (all section numbers refer to the ACPI 6.1 specfication):
> >
> > -- RSDP (Root System Description Pointer), section 5.2.5
> >
> > @@ -185,9 +185,22 @@ tables (all section numbers refer to the ACPI 5.1 specfication):
> > -- If PCI is supported, the MCFG (Memory mapped ConFiGuration
> > Table), section 5.2.6, specifically Table 5-31.
> >
> > + -- If booting without a console=<device> kernel parameter is
> > + supported, the SPCR (Serial Port Console Redirection table),
> > + section 5.2.6, specifically Table 5-31.
> > +
> > + -- If virtualization is supported, the IORT (Input Output Remapping
> > + Table, section 5.2.6, specifically Table 5-31.
> > +
> > + -- If NUMA is supported, the SRAT (System Resource Affinity Table)
> > + and SLIT (System Locality distance Information Table), sections
> > + 5.2.16 and 5.2.17, respectively.
> > +
> > If the above tables are not all present, the kernel may or may not be
> > able to boot properly since it may not be able to configure all of the
> > -devices available.
> > +devices available. This list of tables is not meant to be all inclusive;
> > +in some environments other tables may be needed (e.g., any of the APEI
> > +tables from section 18) to support specific functionality.
> >
> >
> > ACPI Detection
> > @@ -233,7 +246,7 @@ that looks like this: Name(KEY0, "value0"). An ACPI device driver would
> > then retrieve the value of the property by evaluating the KEY0 object.
> > However, using Name() this way has multiple problems: (1) ACPI limits
> > names ("KEY0") to four characters unlike DT; (2) there is no industry
> > -wide registry that maintains a list of names, minimzing re-use; (3)
> > +wide registry that maintains a list of names, minimizing re-use; (3)
> > there is also no registry for the definition of property values ("value0"),
> > again making re-use difficult; and (4) how does one maintain backward
> > compatibility as new hardware comes out? The _DSD method was created
> > @@ -434,7 +447,8 @@ 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
> > presented and discussed in the ASWG (ACPI Specification Working Group) which
> > -is a part of the UEFI Forum.
> > +is a part of the UEFI Forum. The current version of the ACPI specification
> > +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.
> > --
> > 2.5.0

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