dt-bindings: iommu: riscv: Add bindings for Tenstorrent RISC-V IOMMU

index d4838c3b3741..3c680e53af64 100644
@@ -32,22 +32,40 @@ properties:
   # should be specified along with 'reg' property providing MMIO location.
   compatible:
     oneOf:
-      - items:
+      - description: Platform (non-PCIe) IOMMU implementations
+        items:
           - enum:
               - qemu,riscv-iommu
           - const: riscv,iommu
-      - items:
+      - description: PCIe IOMMU implementations
+        items:
           - enum:
               - pci1efd,edf1
           - const: riscv,pci-iommu
+      - description: Tenstorrent IOMMUs implementing "riscv,iommu"
+        items:
+          - enum:
+              - tenstorrent,riscv-iommu
+          - const: riscv,iommu
 
   reg:
-    maxItems: 1
+    minItems: 1
+    maxItems: 2
     description:
-      For non-PCI devices this represents base address and size of for the
-      IOMMU memory mapped registers interface.
-      For PCI IOMMU hardware implementation this should represent an address
-      of the IOMMU, as defined in the PCI Bus Binding reference.
+      For non-PCI devices the first item represents base address and size of
+      for the IOMMU memory mapped registers interface.
+      For PCI IOMMU hardware implementation the first item should represent
+      an address of the IOMMU, as defined in the PCI Bus Binding reference.
+
+  reg-names:
+    items:
+      - const: base
+        description:
+          Minimum 4KiB region beginning with RISC-V IOMMU MMRs.
+      - const: machine
+        description:
+          Optional region containing platform specific MMRs for machine-mode
+          configuration, for example PMA and PMP registers.
 
   '#iommu-cells':
     const: 1

@@ -75,6 +93,31 @@ required:
 
 additionalProperties: false
 
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - tenstorrent,riscv-iommu
+    then:
+      properties:
+        reg:
+          items:
+            - description: IOMMU base registers
+            - description: Tenstorrent IOMMU machine mode registers.
+        reg-names:
+          items:
+            - const: base
+            - const: machine
+              description:
+                Region containing platform specific MMRs for machine-mode
+                configuration, such as PMA and PMP registers.
+    else:
+      properties:
+        reg:
+          maxItems: 1
+
 examples:
   - |+
     /* Example 1 (IOMMU device with wired interrupts) */

@@ -145,3 +188,13 @@ examples:
             };
         };
     };
+
+  - |+
+    /* Example 5 (Tenstorrent IOMMU device with MSIs) */
+    iommu5: iommu@d2020000 {
+        compatible = "tenstorrent,riscv-iommu", "riscv,iommu";
+        reg = <0x0 0xd2020000 0x0 0x10000 0x0 0xaa000000 0x0 0x10000>;
+        reg-names = "base", "machine";
+        msi-parent = <&imsics_smode>;
+        #iommu-cells = <1>;
+    };