On Thu, 13 Feb 2020 17:50:39 +0100, Jean-Philippe Brucker 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. > > Signed-off-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx> > --- > Documentation/devicetree/bindings/pci/host-generic-pci.yaml | 6 ++++++ > 1 file changed, 6 insertions(+) > Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
