iommu: Add helpers to set/get default domain type

Add a couple of functions to allow changing the default
domain type from architecture code and a function for iommu
drivers to request whether the default domain is
passthrough.

Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/iommu.c

@@ -2213,6 +2213,28 @@ int iommu_request_dma_domain_for_dev(struct device *dev)
 	return request_default_domain_for_dev(dev, IOMMU_DOMAIN_DMA);
 }
 
+void iommu_set_default_passthrough(bool cmd_line)
+{
+	if (cmd_line)
+		iommu_set_cmd_line_dma_api();
+
+	iommu_def_domain_type = IOMMU_DOMAIN_IDENTITY;
+}
+
+void iommu_set_default_translated(bool cmd_line)
+{
+	if (cmd_line)
+		iommu_set_cmd_line_dma_api();
+
+	iommu_def_domain_type = IOMMU_DOMAIN_DMA;
+}
+
+bool iommu_default_passthrough(void)
+{
+	return iommu_def_domain_type == IOMMU_DOMAIN_IDENTITY;
+}
+EXPORT_SYMBOL_GPL(iommu_default_passthrough);
+
 const struct iommu_ops *iommu_ops_from_fwnode(struct fwnode_handle *fwnode)
 {
 	const struct iommu_ops *ops = NULL;