diff -drupN a/fs/yaffs2/yaffs_endian.h b/fs/yaffs2/yaffs_endian.h
--- a/fs/yaffs2/yaffs_endian.h	1970-01-01 03:00:00.000000000 +0300
+++ b/fs/yaffs2/yaffs_endian.h	2022-06-09 05:02:35.000000000 +0300
@@ -0,0 +1,54 @@
+/*
+ * YAFFS: Yet another Flash File System . A NAND-flash specific file system.
+ *
+ * Copyright (C) 2002-2018 Aleph One Ltd.
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 2.1 as
+ * published by the Free Software Foundation.
+ *
+ * Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL.
+ */
+
+#ifndef __YAFFS_ENDIAN_H__
+#define __YAFFS_ENDIAN_H__
+#include "yaffs_guts.h"
+#include "yaffs_packedtags2.h"
+
+static inline u32 swap_u32(u32 val)
+{
+	return ((val >>24) & 0x000000ff) |
+	       ((val >> 8) & 0x0000ff00) |
+	       ((val << 8) & 0x00ff0000) |
+	       ((val <<24) & 0xff000000);
+}
+
+#define swap_s32(val) \
+	(s32)(swap_u32((u32)(val)))
+
+static inline loff_t swap_loff_t(loff_t lval)
+{
+	u32 vall = swap_u32(FSIZE_LOW(lval));
+	u32 valh;
+
+	if (sizeof(loff_t) == sizeof(u32))
+		return (loff_t) vall;
+
+	valh = swap_u32(FSIZE_HIGH(lval));
+
+	return FSIZE_COMBINE(vall, valh); /*NB: h and l are swapped. */
+}
+
+
+
+struct yaffs_dev;
+void yaffs_do_endian_s32(struct yaffs_dev *dev, s32 *val);
+void yaffs_do_endian_u32(struct yaffs_dev *dev, u32 *val);
+void yaffs_do_endian_oh(struct yaffs_dev *dev, struct yaffs_obj_hdr *oh);
+void yaffs_do_endian_packed_tags2(struct yaffs_dev *dev,
+				struct yaffs_packed_tags2_tags_only *ptt);
+void yaffs_endian_config(struct yaffs_dev *dev);
+
+#endif