iommu/ipmmu-vmsa: Add device tree bindings documentation

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>

diff --git a/Documentation/devicetree/bindings/iommu/renesas,ipmmu-vmsa.txt b/Documentation/devicetree/bindings/iommu/renesas,ipmmu-vmsa.txt
new file mode 100644 (file)
index 0000000..cd29083
--- /dev/null
+++ b/Documentation/devicetree/bindings/iommu/renesas,ipmmu-vmsa.txt
@@ -0,0 +1,41 @@
+* Renesas VMSA-Compatible IOMMU
+
+The IPMMU is an IOMMU implementation compatible with the ARM VMSA page tables.
+It provides address translation for bus masters outside of the CPU, each
+connected to the IPMMU through a port called micro-TLB.
+
+
+Required Properties:
+
+  - compatible: Must contain "renesas,ipmmu-vmsa".
+  - reg: Base address and size of the IPMMU registers.
+  - interrupts: Specifiers for the MMU fault interrupts. For instances that
+    support secure mode two interrupts must be specified, for non-secure and
+    secure mode, in that order. For instances that don't support secure mode a
+    single interrupt must be specified.
+
+  - #iommu-cells: Must be 1.
+
+Each bus master connected to an IPMMU must reference the IPMMU in its device
+node with the following property:
+
+  - iommus: A reference to the IPMMU in two cells. The first cell is a phandle
+    to the IPMMU and the second cell the number of the micro-TLB that the
+    device is connected to.
+
+
+Example: R8A7791 IPMMU-MX and VSP1-D0 bus master
+
+       ipmmu_mx: mmu@fe951000 {
+               compatible = "renasas,ipmmu-vmsa";
+               reg = <0 0xfe951000 0 0x1000>;
+               interrupts = <0 222 IRQ_TYPE_LEVEL_HIGH>,
+                            <0 221 IRQ_TYPE_LEVEL_HIGH>;
+               #iommu-cells = <1>;
+       };
+
+       vsp1@fe928000 {
+               ...
+               iommus = <&ipmmu_mx 13>;
+               ...
+       };