On Arm systems, some platform devices behind an SMMU may support the PASID feature, which offers multiple address space. Let the firmware tell us when a device supports PASID. Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> Reviewed-by: Rob Herring <robh@xxxxxxxxxx> Signed-off-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx> --- Documentation/devicetree/bindings/iommu/iommu.txt | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Documentation/devicetree/bindings/iommu/iommu.txt b/Documentation/devicetree/bindings/iommu/iommu.txt index 5a8b4624defc..3c36334e4f94 100644 --- a/Documentation/devicetree/bindings/iommu/iommu.txt +++ b/Documentation/devicetree/bindings/iommu/iommu.txt @@ -86,6 +86,12 @@ have a means to turn off translation. But it is invalid in such cases to disable the IOMMU's device tree node in the first place because it would prevent any driver from properly setting up the translations. +Optional properties: +-------------------- +- pasid-num-bits: Some masters support multiple address spaces for DMA, by + tagging DMA transactions with an address space identifier. By default, + this is 0, which means that the device only has one address space. + Notes: ====== -- 2.24.1
