diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/devicetree/bindings/virtio/iommu.txt | 66 | ||||
| -rw-r--r-- | Documentation/devicetree/bindings/virtio/mmio.txt | 30 |
2 files changed, 96 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/virtio/iommu.txt b/Documentation/devicetree/bindings/virtio/iommu.txt new file mode 100644 index 000000000000..2407fea0651c --- /dev/null +++ b/Documentation/devicetree/bindings/virtio/iommu.txt @@ -0,0 +1,66 @@ +* virtio IOMMU PCI device + +When virtio-iommu uses the PCI transport, its programming interface is +discovered dynamically by the PCI probing infrastructure. However the +device tree statically describes the relation between IOMMU and DMA +masters. Therefore, the PCI root complex that hosts the virtio-iommu +contains a child node representing the IOMMU device explicitly. + +Required properties: + +- compatible: Should be "virtio,pci-iommu" +- reg: PCI address of the IOMMU. As defined in the PCI Bus + Binding reference [1], the reg property is a five-cell + address encoded as (phys.hi phys.mid phys.lo size.hi + size.lo). phys.hi should contain the device's BDF as + 0b00000000 bbbbbbbb dddddfff 00000000. The other cells + should be zero. +- #iommu-cells: Each platform DMA master managed by the IOMMU is assigned + an endpoint ID, described by the "iommus" property [2]. + For virtio-iommu, #iommu-cells must be 1. + +Notes: + +- DMA from the IOMMU device isn't managed by another IOMMU. Therefore the + virtio-iommu node doesn't have an "iommus" property, and is omitted from + the iommu-map property of the root complex. + +Example: + +pcie@10000000 { + compatible = "pci-host-ecam-generic"; + ... + + /* The IOMMU programming interface uses slot 00:01.0 */ + iommu0: iommu@0008 { + compatible = "virtio,pci-iommu"; + reg = <0x00000800 0 0 0 0>; + #iommu-cells = <1>; + }; + + /* + * The IOMMU manages all functions in this PCI domain except + * itself. Omit BDF 00:01.0. + */ + iommu-map = <0x0 &iommu0 0x0 0x8> + <0x9 &iommu0 0x9 0xfff7>; +}; + +pcie@20000000 { + compatible = "pci-host-ecam-generic"; + ... + /* + * The IOMMU also manages all functions from this domain, + * with endpoint IDs 0x10000 - 0x1ffff + */ + iommu-map = <0x0 &iommu0 0x10000 0x10000>; +}; + +ethernet@fe001000 { + ... + /* The IOMMU manages this platform device with endpoint ID 0x20000 */ + iommus = <&iommu0 0x20000>; +}; + +[1] Documentation/devicetree/bindings/pci/pci.txt +[2] Documentation/devicetree/bindings/iommu/iommu.txt diff --git a/Documentation/devicetree/bindings/virtio/mmio.txt b/Documentation/devicetree/bindings/virtio/mmio.txt index 5069c1b8e193..21af30fbb81f 100644 --- a/Documentation/devicetree/bindings/virtio/mmio.txt +++ b/Documentation/devicetree/bindings/virtio/mmio.txt @@ -8,10 +8,40 @@ Required properties: - reg: control registers base address and size including configuration space - interrupts: interrupt generated by the device +Required properties for virtio-iommu: + +- #iommu-cells: When the node corresponds to a virtio-iommu device, it is + linked to DMA masters using the "iommus" or "iommu-map" + properties [1][2]. #iommu-cells specifies the size of the + "iommus" property. For virtio-iommu #iommu-cells must be + 1, each cell describing a single endpoint ID. + +Optional properties: + +- iommus: If the device accesses memory through an IOMMU, it should + have an "iommus" property [1]. Since virtio-iommu itself + does not access memory through an IOMMU, the "virtio,mmio" + node cannot have both an "#iommu-cells" and an "iommus" + property. + Example: virtio_block@3000 { compatible = "virtio,mmio"; reg = <0x3000 0x100>; interrupts = <41>; + + /* Device has endpoint ID 23 */ + iommus = <&viommu 23> } + + viommu: iommu@3100 { + compatible = "virtio,mmio"; + reg = <0x3100 0x100>; + interrupts = <42>; + + #iommu-cells = <1> + } + +[1] Documentation/devicetree/bindings/iommu/iommu.txt +[2] Documentation/devicetree/bindings/pci/pci-iommu.txt |