diff --git a/src/mainboard/amd/gardenia/devicetree.cb b/src/mainboard/amd/gardenia/devicetree.cb
index fc7bde527f..bb90ed43e2 100644
--- a/src/mainboard/amd/gardenia/devicetree.cb
+++ b/src/mainboard/amd/gardenia/devicetree.cb
@@ -13,6 +13,7 @@ chip soc/amd/stoneyridge
 	device domain 0 on
 		subsystemid 0x1022 0x1410 inherit
 		device pci 0.0 on  end # Root Complex
+		device pci 0.2 on  end # IOMMU
 		device pci 1.0 on  end # Internal Graphics P2P bridge 0x98e4
 		device pci 1.1 on  end # Internal Multimedia
 		device pci 2.0 on  end # PCIe Host Bridge
diff --git a/src/mainboard/amd/padmelon/devicetree.cb b/src/mainboard/amd/padmelon/devicetree.cb
index a80539029e..76e7d08948 100644
--- a/src/mainboard/amd/padmelon/devicetree.cb
+++ b/src/mainboard/amd/padmelon/devicetree.cb
@@ -10,6 +10,7 @@ chip soc/amd/stoneyridge
 	device domain 0 on
 		subsystemid 0x1022 0x1410 inherit
 		device pci 0.0 on  end # Root Complex
+		device pci 0.2 on  end # IOMMU
 		device pci 1.0 on  end # Internal Graphics P2P bridge 0x9874
 		device pci 1.1 on  end # Internal Multimedia
 		device pci 2.0 on  end # PCIe Host Bridge