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    SubjectRe: [PATCH 05/11] x86, pci, acpi: Move arch-agnostic MMCONFIG (aka ECAM) and ACPI code out of arch/x86/ directory
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    On 15.10.2015 15:22, Lorenzo Pieralisi wrote:
    > On Mon, Sep 14, 2015 at 03:55:50PM +0100, Tomasz Nowicki wrote:
    >
    > [...]
    >
    >>> Well, I still have not figured out whether on arm64 the raw accessors
    >>> required by ACPICA make sense.
    >>>
    >>> So either arm64 relies on the generic MCFG based raw read and writes
    >>> or we define the global raw read and writes as empty (ie x86 overrides
    >>> them anyway).
    >>>
    >>
    >> My concerns/ideas related to raw accessors for ARM64, please correct me
    >> at any point.
    >>
    >> ACPI spec - chapter: 19.5.96 OperationRegion (Declare Operation Region)
    >> defines PCI_Config as one of region types. Every time ASL opcode
    >> operates on corresponding PCI config space region, ASL interpreter is
    >> dispatching address space to our raw accessors, please see
    >> acpi_ex_pci_config_space_handler, acpi_ev_pci_config_region_setup calls.
    >> What is more important, such operations may happen after (yes after) bus
    >> enumeration, but always raw accessors are called at the end with the
    >> {segment, bus, dev, fn} tuple.
    >>
    >> Giving above, here are some ideas:
    >> 1. We force somehow vendors to avoid operations on PCI config regions in
    >> ASL code. PCI config region definitions still fall into Hardware Reduced
    >> profile, so new ACPICA special subset for ARM64 is need. Then raw ACPI
    >> accessors can be empty (and overridden by x86).
    >
    > I am coming back to this, I am not sure that PCI config based OperationRegions
    > fall into Hardware Reduced profile, I will finally start a thread on ASWG
    > to check that.
    >
    > Other than that, are you posting an updated version of this series soon ?
    > Let me know if you need help refactoring/testing the patches.
    >

    I am planing to send updated version next week, but honestly next
    version does make sense if we figure out raw accessors issue. So I will
    clean up all around meanwhile and optionally raw accessor.

    Of course your help in testing is welcomed. Also please have a look at
    my GICv3/ITS patches, they are important for ACPI PCI.

    Regards,
    Tomasz


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