Re: [PATCH v2 1/3] dt-bindings: PCI: generic: Add ats-supported property

[Will Deacon <will@kernel.org>]

Hi Krzysztof,

On Sat, Jul 06, 2024 at 12:24:31PM +0900, Krzysztof Wilczyński wrote:
> > Add a way for firmware to tell the OS that ATS is supported by the PCI
> > root complex. An endpoint with ATS enabled may send Translation Requests
> > and Translated Memory Requests, which look just like Normal Memory
> > Requests with a non-zero AT field. So a root controller that ignores the
> > AT field may simply forward the request to the IOMMU as a Normal Memory
> > Request, which could end badly. In any case, the endpoint will be
> > unusable.
> > 
> > The ats-supported property allows the OS to only enable ATS in endpoints
> > if the root controller can handle ATS requests. Only add the property to
> > pcie-host-ecam-generic for the moment. For non-generic root controllers,
> > availability of ATS can be inferred from the compatible string.
> 
> Applied to dt-bindings, thank you!
> 
> [1/1] dt-bindings: PCI: generic: Add ats-supported property
>       https://git.kernel.org/pci/pci/c/631b2e7318d45

FWIW: I already picked this up in the IOMMU tree last week. If you need
it to avoid a conflict, then you can pull from the pci/ats branch:

https://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux.git/commit/?h=pci/ats&id=40929e8e5449a18bc98baf7a907dd6674bd60049

Cheers,

Will