Add support for fastboot sparse images

This adds support for reading Android fastboot sparse images. This
code is based on the corresponding U-Boot code, but has been heavily
modified to provide a read-like API which better fits into barebox.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 67 insertions, 0 deletions

diff --git a/include/image-sparse.h b/include/image-sparse.h
new file mode 100644
index 0000000000..29242f4fd5
--- /dev/null
+++ b/include/image-sparse.h
@@ -0,0 +1,67 @@
+/*
+ * 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 _IMAGE_SPARSE_H
+#define _IMAGE_SPARSE_H
+
+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 */
+};
+
+#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
+
+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 */
+};
+
+/* 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
+ */
+
+static inline int is_sparse_image(const void *buf)
+{
+	const struct sparse_header *s = buf;
+
+	if ((le32_to_cpu(s->magic) == SPARSE_HEADER_MAGIC) &&
+	    (le16_to_cpu(s->major_version) == 1))
+		return 1;
+
+	return 0;
+}
+
+struct sparse_image_ctx;
+
+struct sparse_image_ctx *sparse_image_open(const char *path);
+int sparse_image_read(struct sparse_image_ctx *si, void *buf,
+		      loff_t *pos, size_t len, int *retlen);
+void sparse_image_close(struct sparse_image_ctx *si);
+loff_t sparse_image_size(struct sparse_image_ctx *si);
+
+#endif /* _IMAGE_SPARSE_H */