diff --git a/src/northbridge/amd/agesa/family15tn/iommu.c b/src/northbridge/amd/agesa/family15tn/iommu.c
index 7af65389f3..587e737846 100644
--- a/src/northbridge/amd/agesa/family15tn/iommu.c
+++ b/src/northbridge/amd/agesa/family15tn/iommu.c
@@ -13,7 +13,7 @@ static void iommu_read_resources(struct device *dev)
 	/* Get the normal pci resources of this device */
 	pci_dev_read_resources(dev);
 
-	/* Add an extra subtractive resource for both memory and I/O. */
+	/* IOMMU MMIO registers */
 	res = new_resource(dev, 0x44);
 	res->size = 512 * 1024;
 	res->align = log2(res->size);
diff --git a/src/northbridge/amd/pi/00730F01/iommu.c b/src/northbridge/amd/pi/00730F01/iommu.c
index ef478dda15..c79ddb56e6 100644
--- a/src/northbridge/amd/pi/00730F01/iommu.c
+++ b/src/northbridge/amd/pi/00730F01/iommu.c
@@ -12,7 +12,7 @@ static void iommu_read_resources(struct device *dev)
 	/* Get the normal pci resources of this device */
 	pci_dev_read_resources(dev);
 
-	/* Add an extra subtractive resource for both memory and I/O. */
+	/* IOMMU MMIO registers */
 	res = new_resource(dev, 0x44);
 	res->size = 512 * 1024;
 	res->align = log2(res->size);
diff --git a/src/soc/amd/common/block/iommu/iommu.c b/src/soc/amd/common/block/iommu/iommu.c
index 67abe9e66d..9d4f38e8d9 100644
--- a/src/soc/amd/common/block/iommu/iommu.c
+++ b/src/soc/amd/common/block/iommu/iommu.c
@@ -12,7 +12,7 @@ static void iommu_read_resources(struct device *dev)
 	/* Get the normal pci resources of this device */
 	pci_dev_read_resources(dev);
 
-	/* Add an extra subtractive resource for both memory and I/O. */
+	/* IOMMU MMIO registers */
 	res = new_resource(dev, 0x44);
 	res->size = 512 * KiB;
 	res->align = log2(res->size);