65 lines
2.3 KiB
Plaintext
65 lines
2.3 KiB
Plaintext
* QCOM IOMMU
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The MSM IOMMU is an implementation compatible with the ARM VMSA short
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descriptor page tables. It provides address translation for bus masters outside
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of the CPU, each connected to the IOMMU through a port called micro-TLB.
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Required Properties:
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- compatible: Must contain "qcom,apq8064-iommu".
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- reg: Base address and size of the IOMMU registers.
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- interrupts: Specifiers for the MMU fault interrupts. For instances that
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support secure mode two interrupts must be specified, for non-secure and
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secure mode, in that order. For instances that don't support secure mode a
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single interrupt must be specified.
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- #iommu-cells: The number of cells needed to specify the stream id. This
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is always 1.
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- qcom,ncb: The total number of context banks in the IOMMU.
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- clocks : List of clocks to be used during SMMU register access. See
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Documentation/devicetree/bindings/clock/clock-bindings.txt
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for information about the format. For each clock specified
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here, there must be a corresponding entry in clock-names
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(see below).
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- clock-names : List of clock names corresponding to the clocks specified in
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the "clocks" property (above).
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Should be "smmu_pclk" for specifying the interface clock
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required for iommu's register accesses.
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Should be "smmu_clk" for specifying the functional clock
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required by iommu for bus accesses.
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Each bus master connected to an IOMMU must reference the IOMMU in its device
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node with the following property:
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- iommus: A reference to the IOMMU in multiple cells. The first cell is a
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phandle to the IOMMU and the second cell is the stream id.
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A single master device can be connected to more than one iommu
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and multiple contexts in each of the iommu. So multiple entries
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are required to list all the iommus and the stream ids that the
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master is connected to.
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Example: mdp iommu and its bus master
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mdp_port0: iommu@7500000 {
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compatible = "qcom,apq8064-iommu";
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#iommu-cells = <1>;
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clock-names =
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"smmu_pclk",
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"smmu_clk";
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clocks =
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<&mmcc SMMU_AHB_CLK>,
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<&mmcc MDP_AXI_CLK>;
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reg = <0x07500000 0x100000>;
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interrupts =
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<GIC_SPI 63 0>,
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<GIC_SPI 64 0>;
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qcom,ncb = <2>;
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};
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mdp: qcom,mdp@5100000 {
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compatible = "qcom,mdp";
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...
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iommus = <&mdp_port0 0
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&mdp_port0 2>;
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};
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