Document how the generic "iommus" binding should be used to describe ARM
SMMU stream IDs instead of the old "mmu-masters" binding.
CC: Rob Herring <robh+dt@xxxxxxxxxx>
CC: Mark Rutland <mark.rutland@xxxxxxx>
Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
---
.../devicetree/bindings/iommu/arm,smmu.txt | 63 ++++++++++++++++------
1 file changed, 48 insertions(+), 15 deletions(-)
diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.txt b/Documentation/devicetree/bindings/iommu/arm,smmu.txt
index 19fe6f2c83f6..e9d447cf3a76 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:
- 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 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.
+
+** 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>;
-
- /*
- * 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>;
+ #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>;
+ };
+
+ /* device with stream IDs 1, 17, 33 and 49 */
+ master3 {
+ iommus = <&smmu2 1 0x30>;
};
--
2.8.1.dirty
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