[PATCH v2] ACPI/IORT: Fix PCI ACS enablement

[Catalin Marinas]

On Mon, Oct 02, 2017 at 06:28:44PM +0100, Lorenzo Pieralisi wrote:
> commit f6810c15cf97 ("iommu/arm-smmu: Clean up early-probing
> workarounds") removed kernel code that was allowing to initialize
> and probe the SMMU devices early (ie earlier than PCI devices, through
> linker script callback entries) in the boot process because it was not
> needed any longer in that the SMMU devices/drivers now support deferred
> probing.
> 
> Since the SMMUs probe routines are also in charge of requesting global
> PCI ACS kernel enablement, commit f6810c15cf97 ("iommu/arm-smmu: Clean
> up early-probing workarounds") also postponed PCI ACS enablement to
> SMMUs devices probe time, which is too late given that PCI devices needs
> to detect if PCI ACS is enabled to init the respective capability
> through the following call path:
> 
> pci_device_add()
>  -> pci_init_capabilities()
>   -> pci_enable_acs()
> 
> Add code in the ACPI IORT SMMU platform devices initialization path
> (that is called before ACPI PCI enumeration) to detect if there
> exists firmware mappings to map root complexes ids to SMMU ids
> and if so enable ACS for the system.
> 
> Fixes: f6810c15cf97 ("iommu/arm-smmu: Clean up early-probing
> Signed-workarounds")
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
> Cc: Will Deacon <will.deacon at arm.com>
> Cc: Hanjun Guo <hanjun.guo at linaro.org>
> Cc: Sudeep Holla <sudeep.holla at arm.com>
> Cc: Catalin Marinas <catalin.marinas at arm.com>
> Cc: Robin Murphy <robin.murphy at arm.com>
> Cc: Zhou Wang <wangzhou1 at hisilicon.com>
> Cc: Alex Williamson <alex.williamson at redhat.com>

Queued for 4.14-rc4. Thanks.

-- 
Catalin