add header for Android sparse image format

Add a BSD-3 relicensed version of the Android sparse format image
header from:
https://android.googlesource.com/platform/system/core/+/28fa5bc347390480fe190294c6c385b6a9f0d68b/libsparse/sparse_format.h
Unchanged except for the license header.

Cc: Tom Rini <trini@ti.com>
Signed-off-by: Colin Cross <ccross@android.com>

include/sparse_format.h

@@ -0,0 +1,49 @@
+/*
+ * This is from the Android Project,
+ * Repository: https://android.googlesource.com/platform/system/core
+ * File: libsparse/sparse_format.h
+ * Commit: 28fa5bc347390480fe190294c6c385b6a9f0d68b
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef _LIBSPARSE_SPARSE_FORMAT_H_
+#define _LIBSPARSE_SPARSE_FORMAT_H_
+#include "sparse_defs.h"
+
+typedef struct sparse_header {
+  __le32	magic;		/* 0xed26ff3a */
+  __le16	major_version;	/* (0x1) - reject images with higher major versions */
+  __le16	minor_version;	/* (0x0) - allow images with higer minor versions */
+  __le16	file_hdr_sz;	/* 28 bytes for first revision of the file format */
+  __le16	chunk_hdr_sz;	/* 12 bytes for first revision of the file format */
+  __le32	blk_sz;		/* block size in bytes, must be a multiple of 4 (4096) */
+  __le32	total_blks;	/* total blocks in the non-sparse output image */
+  __le32	total_chunks;	/* total chunks in the sparse input image */
+  __le32	image_checksum; /* CRC32 checksum of the original data, counting "don't care" */
+				/* as 0. Standard 802.3 polynomial, use a Public Domain */
+				/* table implementation */
+} sparse_header_t;
+
+#define SPARSE_HEADER_MAGIC	0xed26ff3a
+
+#define CHUNK_TYPE_RAW		0xCAC1
+#define CHUNK_TYPE_FILL		0xCAC2
+#define CHUNK_TYPE_DONT_CARE	0xCAC3
+#define CHUNK_TYPE_CRC32    0xCAC4
+
+typedef struct chunk_header {
+  __le16	chunk_type;	/* 0xCAC1 -> raw; 0xCAC2 -> fill; 0xCAC3 -> don't care */
+  __le16	reserved1;
+  __le32	chunk_sz;	/* in blocks in output image */
+  __le32	total_sz;	/* in bytes of chunk input file including chunk header and data */
+} chunk_header_t;
+
+/* Following a Raw or Fill or CRC32 chunk is data.
+ *  For a Raw chunk, it's the data in chunk_sz * blk_sz.
+ *  For a Fill chunk, it's 4 bytes of the fill data.
+ *  For a CRC32 chunk, it's 4 bytes of CRC32
+ */
+
+#endif