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diff --git a/include/dm/ofnode_decl.h b/include/dm/ofnode_decl.h
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+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2022 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#ifndef _DM_OFNODE_DECL_H
+#define _DM_OFNODE_DECL_H
+
+/**
+ * typedef union ofnode_union ofnode - reference to a device tree node
+ *
+ * This union can hold either a straightforward pointer to a struct device_node
+ * in the live device tree, or an offset within the flat device tree. In the
+ * latter case, the pointer value is just the integer offset within the flat DT.
+ *
+ * Thus we can reference nodes in both the live tree (once available) and the
+ * flat tree (until then). Functions are available to translate between an
+ * ofnode and either an offset or a `struct device_node *`.
+ *
+ * The reference can also hold a null offset, in which case the pointer value
+ * here is NULL. This corresponds to a struct device_node * value of
+ * NULL, or an offset of -1.
+ *
+ * There is no ambiguity as to whether ofnode holds an offset or a node
+ * pointer: when the live tree is active it holds a node pointer, otherwise it
+ * holds an offset. The value itself does not need to be unique and in theory
+ * the same value could point to a valid device node or a valid offset. We
+ * could arrange for a unique value to be used (e.g. by making the pointer
+ * point to an offset within the flat device tree in the case of an offset) but
+ * this increases code size slightly due to the subtraction. Since it offers no
+ * real benefit, the approach described here seems best.
+ *
+ * For now these points use constant types, since we don't allow writing
+ * the DT.
+ *
+ * @np: Pointer to device node, used for live tree
+ * @of_offset: Pointer into flat device tree, used for flat tree. Note that this
+ *	is not a really a pointer to a node: it is an offset value. See above.
+ */
+typedef union ofnode_union {
+	const struct device_node *np;
+	long of_offset;
+} ofnode;
+
+/**
+ * struct ofprop - reference to a property of a device tree node
+ *
+ * This struct hold the reference on one property of one node,
+ * using struct ofnode and an offset within the flat device tree or either
+ * a pointer to a struct property in the live device tree.
+ *
+ * Thus we can reference arguments in both the live tree and the flat tree.
+ *
+ * The property reference can also hold a null reference. This corresponds to
+ * a struct property NULL pointer or an offset of -1.
+ *
+ * @node: Pointer to device node
+ * @offset: Pointer into flat device tree, used for flat tree.
+ * @prop: Pointer to property, used for live treee.
+ */
+
+struct ofprop {
+	ofnode node;
+	union {
+		int offset;
+		const struct property *prop;
+	};
+};
+
+/**
+ * union oftree_union - reference to a tree of device tree nodes
+ *
+ * One or other of the members is used, depending on of_live_active()
+ *
+ * @np: Pointer to roott device node, used for live tree
+ * @fdt: Pointer to the flat device tree, used for flat tree
+ */
+typedef union oftree_union {
+	struct device_node *np;
+	void *fdt;
+} oftree;
+
+#endif
+