From d0acbb750a22bc8961c746bc9cad5937a9d9a83d Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Mon, 12 Sep 2016 17:13:56 +0100 Subject: [PATCH] Docs: dt: document ARM SMMU generic binding usage Document how the generic "iommus" binding should be used to describe ARM SMMU stream IDs instead of the old "mmu-masters" binding. Acked-by: Rob Herring Signed-off-by: Robin Murphy Signed-off-by: Will Deacon --- .../devicetree/bindings/iommu/arm,smmu.txt | 61 ++++++++++++++----- 1 file changed, 47 insertions(+), 14 deletions(-) diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.txt b/Documentation/devicetree/bindings/iommu/arm,smmu.txt index 19fe6f2c83f6..e862d1485205 100644 --- a/Documentation/devicetree/bindings/iommu/arm,smmu.txt +++ b/Documentation/devicetree/bindings/iommu/arm,smmu.txt @@ -35,12 +35,16 @@ conditions. 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. +- #iommu-cells : See Documentation/devicetree/bindings/iommu/iommu.txt + for details. With a value of 1, each "iommus" entry + represents a distinct stream ID emitted by that device + into the relevant SMMU. + + SMMUs with stream matching support and complex masters + may use a value of 2, where the second cell represents + an SMR mask to combine with the ID in the first cell. + Care must be taken to ensure the set of matched IDs + does not result in conflicts. ** System MMU optional properties: @@ -56,9 +60,20 @@ conditions. aliases of secure registers have to be used during SMMU configuration. -Example: +** Deprecated properties: + +- mmu-masters (deprecated in favour of the generic "iommus" binding) : + A list of phandles to device nodes representing bus + masters for which the SMMU can provide a translation + and their corresponding Stream IDs. Each device node + linked from this list must have a "#stream-id-cells" + property, indicating the number of Stream ID + arguments associated with its phandle. - smmu { +** Examples: + + /* SMMU with stream matching or stream indexing */ + smmu1: iommu { compatible = "arm,smmu-v1"; reg = <0xba5e0000 0x10000>; #global-interrupts = <2>; @@ -68,11 +83,29 @@ Example: <0 35 4>, <0 36 4>, <0 37 4>; + #iommu-cells = <1>; + }; + + /* device with two stream IDs, 0 and 7 */ + master1 { + iommus = <&smmu1 0>, + <&smmu1 7>; + }; + + + /* SMMU with stream matching */ + smmu2: iommu { + ... + #iommu-cells = <2>; + }; + + /* device with stream IDs 0 and 7 */ + master2 { + iommus = <&smmu2 0 0>, + <&smmu2 7 0>; + }; - /* - * 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>; + /* device with stream IDs 1, 17, 33 and 49 */ + master3 { + iommus = <&smmu2 1 0x30>; }; -- 2.20.1