From 631b2e7318d45bb0f1a5490c9a9e0509b67629ee Mon Sep 17 00:00:00 2001 From: Jean-Philippe Brucker Date: Fri, 7 Jun 2024 11:54:14 +0100 Subject: dt-bindings: PCI: generic: Add ats-supported property MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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. Link: https://lore.kernel.org/linux-pci/20240607105415.2501934-3-jean-philippe@linaro.org Signed-off-by: Jean-Philippe Brucker Signed-off-by: Krzysztof Wilczyński Reviewed-by: Jason Gunthorpe Reviewed-by: Liviu Dudau Reviewed-by: Nicolin Chen Reviewed-by: Rob Herring Reviewed-by: Robin Murphy --- Documentation/devicetree/bindings/pci/host-generic-pci.yaml | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Documentation/devicetree/bindings/pci/host-generic-pci.yaml b/Documentation/devicetree/bindings/pci/host-generic-pci.yaml index 3484e0b4b412..bcfbaf5582cc 100644 --- a/Documentation/devicetree/bindings/pci/host-generic-pci.yaml +++ b/Documentation/devicetree/bindings/pci/host-generic-pci.yaml @@ -110,6 +110,12 @@ properties: iommu-map-mask: true msi-parent: true + ats-supported: + description: + Indicates that a PCIe host controller supports ATS, and can handle Memory + Requests with Address Type (AT). + type: boolean + required: - compatible - reg -- cgit