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Commit b79802e7 authored by Robin Murphy's avatar Robin Murphy Committed by Patrick Daly
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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.

Change-Id: I6cc28bacedd5af5b3398893e341f5b8cd5733054
Acked-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Git-commit: d0acbb75
Git-repo: https://source.codeaurora.org/quic/la/kernel/msm-4.4


Signed-off-by: default avatarPatrick Daly <pdaly@codeaurora.org>
parent 06e393e7

Documentation/devicetree/bindings/iommu/arm,smmu.txt

+46 −17
Original line number Diff line number Diff line
@@ -37,12 +37,16 @@ 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:
@@ -104,9 +108,20 @@ conditions. 
- qcom,msm-bus,vectors-KBps

		: Refer to devicetree/bindings/arm/msm/msm_bus.txt



Example:

** Deprecated properties:



        smmu {

- 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.



** Examples:



        /* SMMU with stream matching or stream indexing */

        smmu1: iommu {

                compatible = "arm,smmu-v1";

                reg = <0xba5e0000 0x10000>;

                #global-interrupts = <2>;
@@ -116,17 +131,31 @@ 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>;

        };





                /*

                 * 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>;

        /* SMMU with stream matching */

        smmu2: iommu {

                ...

                #iommu-cells = <2>;

        };



        /* device with stream IDs 0 and 7 */

        master2 {

                iommus = <&smmu2 0 0>,

                         <&smmu2 7 0>;

        };



                attach-impl-defs = <0x124 0x3>,

                    <0x128 0xa5>,

                    <0x12c 0x1>;

        /* device with stream IDs 1, 17, 33 and 49 */

        master3 {

                iommus = <&smmu2 1 0x30>;

        };