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authorWill Deacon <will.deacon@arm.com>2013-06-24 21:31:24 +0400
committerJoerg Roedel <joro@8bytes.org>2013-06-26 01:33:43 +0400
commit98c33c5a971bbca31160e5e4a362496c4d702357 (patch)
tree70339db569080639da81adac669cf09f2335fda9 /Documentation/devicetree/bindings/iommu
parent9e895ace5d82df8929b16f58e9f515f6d54ab82d (diff)
downloadlinux-98c33c5a971bbca31160e5e4a362496c4d702357.tar.xz
documentation/iommu: Add description of ARM System MMU binding
This patch adds a description of the device tree binding for the ARM System MMU architecture. Cc: Rob Herring <robherring2@gmail.com> Cc: Andreas Herrmann <andreas.herrmann@calxeda.com> Cc: Joerg Roedel <joro@8bytes.org> Acked-by: Grant Likely <grant.likely@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Acked-by: Andreas Herrmann <andreas.herrmann@calxeda.com> Signed-off-by: Joerg Roedel <joro@8bytes.org>
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+* ARM System MMU Architecture Implementation
+
+ARM SoCs may contain an implementation of the ARM System Memory
+Management Unit Architecture, which can be used to provide 1 or 2 stages
+of address translation to bus masters external to the CPU.
+
+The SMMU may also raise interrupts in response to various fault
+conditions.
+
+** System MMU required properties:
+
+- compatible : Should be one of:
+
+ "arm,smmu-v1"
+ "arm,smmu-v2"
+ "arm,mmu-400"
+ "arm,mmu-500"
+
+ depending on the particular implementation and/or the
+ version of the architecture implemented.
+
+- reg : Base address and size of the SMMU.
+
+- #global-interrupts : The number of global interrupts exposed by the
+ device.
+
+- interrupts : Interrupt list, with the first #global-irqs entries
+ corresponding to the global interrupts and any
+ following entries corresponding to context interrupts,
+ specified in order of their indexing by the SMMU.
+
+ For SMMUv2 implementations, there must be exactly one
+ interrupt per context bank. In the case of a single,
+ combined interrupt, it must be listed multiple times.
+
+- mmu-masters : A list of phandles to device nodes representing bus
+ masters for which the SMMU can provide a translation
+ and their corresponding StreamIDs (see example below).
+ Each device node linked from this list must have a
+ "#stream-id-cells" property, indicating the number of
+ StreamIDs associated with it.
+
+** System MMU optional properties:
+
+- smmu-parent : When multiple SMMUs are chained together, this
+ property can be used to provide a phandle to the
+ parent SMMU (that is the next SMMU on the path going
+ from the mmu-masters towards memory) node for this
+ SMMU.
+
+Example:
+
+ smmu {
+ compatible = "arm,smmu-v1";
+ reg = <0xba5e0000 0x10000>;
+ #global-interrupts = <2>;
+ interrupts = <0 32 4>,
+ <0 33 4>,
+ <0 34 4>, /* This is the first context interrupt */
+ <0 35 4>,
+ <0 36 4>,
+ <0 37 4>;
+
+ /*
+ * Two DMA controllers, the first with two StreamIDs (0xd01d
+ * and 0xd01e) and the second with only one (0xd11c).
+ */
+ mmu-masters = <&dma0 0xd01d 0xd01e>,
+ <&dma1 0xd11c>;
+ };