v4.19.13 snapshot.
diff --git a/include/linux/of_pdt.h b/include/linux/of_pdt.h
new file mode 100644
index 0000000..d0b183a
--- /dev/null
+++ b/include/linux/of_pdt.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Definitions for building a device tree by calling into the
+ * Open Firmware PROM.
+ *
+ * Copyright (C) 2010 Andres Salomon <dilinger@queued.net>
+ */
+
+#ifndef _LINUX_OF_PDT_H
+#define _LINUX_OF_PDT_H
+
+/* overridable operations for calling into the PROM */
+struct of_pdt_ops {
+ /*
+ * buf should be 32 bytes; return 0 on success.
+ * If prev is NULL, the first property will be returned.
+ */
+ int (*nextprop)(phandle node, char *prev, char *buf);
+
+ /* for both functions, return proplen on success; -1 on error */
+ int (*getproplen)(phandle node, const char *prop);
+ int (*getproperty)(phandle node, const char *prop, char *buf,
+ int bufsize);
+
+ /* phandles are 0 if no child or sibling exists */
+ phandle (*getchild)(phandle parent);
+ phandle (*getsibling)(phandle node);
+
+ /* return 0 on success; fill in 'len' with number of bytes in path */
+ int (*pkg2path)(phandle node, char *buf, const int buflen, int *len);
+};
+
+extern void *prom_early_alloc(unsigned long size);
+
+/* for building the device tree */
+extern void of_pdt_build_devicetree(phandle root_node, struct of_pdt_ops *ops);
+
+extern void (*of_pdt_build_more)(struct device_node *dp);
+
+#endif /* _LINUX_OF_PDT_H */