diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 8cb60829a7a1..be8ac1ddec06 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -140,75 +140,39 @@ static const struct iommu_ops
 	return ops;
 }
 
-static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data)
-{
-	struct of_phandle_args *iommu_spec = data;
+struct of_pci_iommu_alias_info {
+	struct device *dev;
+	struct device_node *np;
+};
 
-	iommu_spec->args[0] = alias;
-	return iommu_spec->np == pdev->bus->dev.of_node;
-}
-
-static const struct iommu_ops
-*of_pci_iommu_init(struct pci_dev *pdev, struct device_node *bridge_np)
+static int of_pci_iommu_init(struct pci_dev *pdev, u16 alias, void *data)
 {
+	struct of_pci_iommu_alias_info *info = data;
 	const struct iommu_ops *ops;
-	struct of_phandle_args iommu_spec;
+	struct of_phandle_args iommu_spec = { .args_count = 1 };
 	int err;
 
-	/*
-	 * Start by tracing the RID alias down the PCI topology as
-	 * far as the host bridge whose OF node we have...
-	 * (we're not even attempting to handle multi-alias devices yet)
-	 */
-	iommu_spec.args_count = 1;
-	iommu_spec.np = bridge_np;
-	pci_for_each_dma_alias(pdev, __get_pci_rid, &iommu_spec);
-	/*
-	 * ...then find out what that becomes once it escapes the PCI
-	 * bus into the system beyond, and which IOMMU it ends up at.
-	 */
-	iommu_spec.np = NULL;
-	err = of_pci_map_rid(bridge_np, iommu_spec.args[0], "iommu-map",
+	err = of_pci_map_rid(info->np, alias, "iommu-map",
 			     "iommu-map-mask", &iommu_spec.np,
 			     iommu_spec.args);
 	if (err)
-		return err == -ENODEV ? NULL : ERR_PTR(err);
-
-	ops = of_iommu_xlate(&pdev->dev, &iommu_spec);
+		return err == -ENODEV ? 1 : err;
 
+	ops = of_iommu_xlate(info->dev, &iommu_spec);
 	of_node_put(iommu_spec.np);
-	return ops;
-}
 
-static const struct iommu_ops
-*of_platform_iommu_init(struct device *dev, struct device_node *np)
-{
-	struct of_phandle_args iommu_spec;
-	const struct iommu_ops *ops = NULL;
-	int idx = 0;
+	if (IS_ERR(ops))
+		return PTR_ERR(ops);
 
-	/*
-	 * We don't currently walk up the tree looking for a parent IOMMU.
-	 * See the `Notes:' section of
-	 * Documentation/devicetree/bindings/iommu/iommu.txt
-	 */
-	while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells",
-					   idx, &iommu_spec)) {
-		ops = of_iommu_xlate(dev, &iommu_spec);
-		of_node_put(iommu_spec.np);
-		idx++;
-		if (IS_ERR_OR_NULL(ops))
-			break;
-	}
-
-	return ops;
+	return info->np == pdev->bus->dev.of_node;
 }
 
 const struct iommu_ops *of_iommu_configure(struct device *dev,
 					   struct device_node *master_np)
 {
-	const struct iommu_ops *ops;
+	const struct iommu_ops *ops = NULL;
 	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
+	int err;
 
 	if (!master_np)
 		return NULL;
@@ -221,18 +185,44 @@ const struct iommu_ops *of_iommu_configure(struct device *dev,
 		iommu_fwspec_free(dev);
 	}
 
-	if (dev_is_pci(dev))
-		ops = of_pci_iommu_init(to_pci_dev(dev), master_np);
-	else
-		ops = of_platform_iommu_init(dev, master_np);
+	/*
+	 * We don't currently walk up the tree looking for a parent IOMMU.
+	 * See the `Notes:' section of
+	 * Documentation/devicetree/bindings/iommu/iommu.txt
+	 */
+	if (dev_is_pci(dev)) {
+		struct of_pci_iommu_alias_info info = {
+			.dev = dev,
+			.np = master_np,
+		};
+
+		err = pci_for_each_dma_alias(to_pci_dev(dev),
+					     of_pci_iommu_init, &info);
+		if (err) /* err > 0 means the walk stopped, but non-fatally */
+			ops = ERR_PTR(min(err, 0));
+		else /* success implies both fwspec and ops are now valid */
+			ops = dev->iommu_fwspec->ops;
+	} else {
+		struct of_phandle_args iommu_spec;
+		int idx = 0;
+
+		while (!of_parse_phandle_with_args(master_np, "iommus",
+						   "#iommu-cells",
+						   idx, &iommu_spec)) {
+			ops = of_iommu_xlate(dev, &iommu_spec);
+			of_node_put(iommu_spec.np);
+			idx++;
+			if (IS_ERR_OR_NULL(ops))
+				break;
+		}
+	}
 	/*
 	 * If we have reason to believe the IOMMU driver missed the initial
 	 * add_device callback for dev, replay it to get things in order.
 	 */
 	if (!IS_ERR_OR_NULL(ops) && ops->add_device &&
 	    dev->bus && !dev->iommu_group) {
-		int err = ops->add_device(dev);
-
+		err = ops->add_device(dev);
 		if (err)
 			ops = ERR_PTR(err);
 	}