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| 1 | 1 | * virtio memory mapped device |
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| 2 | 2 | |
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| 3 | | -See http://ozlabs.org/~rusty/virtio-spec/ for more details. |
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| 3 | +See https://ozlabs.org/~rusty/virtio-spec/ for more details. |
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| 4 | 4 | |
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| 5 | 5 | Required properties: |
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| 6 | 6 | |
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| .. | .. |
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| 8 | 8 | - reg: control registers base address and size including configuration space |
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| 9 | 9 | - interrupts: interrupt generated by the device |
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| 10 | 10 | |
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| 11 | +Required properties for virtio-iommu: |
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| 12 | + |
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| 13 | +- #iommu-cells: When the node corresponds to a virtio-iommu device, it is |
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| 14 | + linked to DMA masters using the "iommus" or "iommu-map" |
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| 15 | + properties [1][2]. #iommu-cells specifies the size of the |
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| 16 | + "iommus" property. For virtio-iommu #iommu-cells must be |
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| 17 | + 1, each cell describing a single endpoint ID. |
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| 18 | + |
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| 19 | +Optional properties: |
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| 20 | + |
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| 21 | +- iommus: If the device accesses memory through an IOMMU, it should |
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| 22 | + have an "iommus" property [1]. Since virtio-iommu itself |
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| 23 | + does not access memory through an IOMMU, the "virtio,mmio" |
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| 24 | + node cannot have both an "#iommu-cells" and an "iommus" |
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| 25 | + property. |
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| 26 | + |
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| 11 | 27 | Example: |
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| 12 | 28 | |
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| 13 | 29 | virtio_block@3000 { |
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| 14 | 30 | compatible = "virtio,mmio"; |
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| 15 | 31 | reg = <0x3000 0x100>; |
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| 16 | 32 | interrupts = <41>; |
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| 33 | + |
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| 34 | + /* Device has endpoint ID 23 */ |
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| 35 | + iommus = <&viommu 23> |
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| 17 | 36 | } |
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| 37 | + |
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| 38 | + viommu: iommu@3100 { |
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| 39 | + compatible = "virtio,mmio"; |
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| 40 | + reg = <0x3100 0x100>; |
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| 41 | + interrupts = <42>; |
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| 42 | + |
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| 43 | + #iommu-cells = <1> |
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| 44 | + } |
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| 45 | + |
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| 46 | +[1] Documentation/devicetree/bindings/iommu/iommu.txt |
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| 47 | +[2] Documentation/devicetree/bindings/pci/pci-iommu.txt |
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