diff --git a/acpi-id.adoc b/acpi-id.adoc
index 5cda486..5078c25 100644
--- a/acpi-id.adoc
+++ b/acpi-id.adoc
@@ -28,5 +28,6 @@ ACPI ID for any new device.
 | `RSCV0001`     | RISC-V Platform-Level Interrupt Controller (PLIC)
 | `RSCV0002`     | RISC-V Advanced Platform-Level Interrupt Controller (APLIC)
 | `RSCV0003`     | NS16650 UART compatible with an SPCR definition using `Interface Type` 0x12
+| `RSCV0004`     | RISC-V IOMMU implemented as a platform device
 2+| _Also see <<acpi-props-uart>>._
 |===