3 files changed, 65 insertions, 0 deletions
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
new file mode 100644
index 00000000000..3e35ce8fcc8
--- /dev/null
+++ b/drivers/iommu/Kconfig
@@ -0,0 +1,17 @@
+#
+# IOMMU devices
+#
+
+menu "IOMMU device drivers"
+
+config IOMMU
+	bool "Enable Driver Model for IOMMU drivers"
+	depends on DM
+	help
+	  Enable driver model for IOMMU devices. An IOMMU maps device
+	  virtiual memory addresses to physical addresses. Devices
+	  that sit behind an IOMMU can typically only access physical
+	  memory if the IOMMU has been programmed to allow access to
+	  that memory.
+
+endmenu
diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
new file mode 100644
index 00000000000..f1ceb101507
--- /dev/null
+++ b/drivers/iommu/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0+
+
+obj-$(CONFIG_IOMMU) += iommu-uclass.o
diff --git a/drivers/iommu/iommu-uclass.c b/drivers/iommu/iommu-uclass.c
new file mode 100644
index 00000000000..ed917b3c3e8
--- /dev/null
+++ b/drivers/iommu/iommu-uclass.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2021 Mark Kettenis <kettenis@openbsd.org>
+ */
+
+#define LOG_CATEGORY UCLASS_IOMMU
+
+#include <common.h>
+#include <dm.h>
+
+#if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA))
+int dev_iommu_enable(struct udevice *dev)
+{
+	struct ofnode_phandle_args args;
+	struct udevice *dev_iommu;
+	int i, count, ret = 0;
+
+	count = dev_count_phandle_with_args(dev, "iommus",
+					    "#iommu-cells", 0);
+	for (i = 0; i < count; i++) {
+		ret = dev_read_phandle_with_args(dev, "iommus",
+						 "#iommu-cells", 0, i, &args);
+		if (ret) {
+			debug("%s: dev_read_phandle_with_args failed: %d\n",
+			      __func__, ret);
+			return ret;
+		}
+
+		ret = uclass_get_device_by_ofnode(UCLASS_IOMMU, args.node,
+						  &dev_iommu);
+		if (ret) {
+			debug("%s: uclass_get_device_by_ofnode failed: %d\n",
+			      __func__, ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+#endif
+
+UCLASS_DRIVER(iommu) = {
+	.id		= UCLASS_IOMMU,
+	.name		= "iommu",
+};