common/image-sparse.c - github/trini/u-boot - Gitiles

 /*
  * Copyright (c) 2009, Google Inc.
  * All rights reserved.
  *
  * Copyright (c) 2009-2014, The Linux Foundation. All rights reserved.
  * Portions Copyright 2014 Broadcom Corporation.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *     * Redistributions of source code must retain the above copyright
  *       notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above copyright
  *       notice, this list of conditions and the following disclaimer in the
  *       documentation and/or other materials provided with the distribution.
  *     * Neither the name of The Linux Foundation nor
  *       the names of its contributors may be used to endorse or promote
  *       products derived from this software without specific prior written
  *       permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  * NON-INFRINGEMENT ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * NOTE:
  *   Although it is very similar, this license text is not identical
  *   to the "BSD-3-Clause", therefore, DO NOT MODIFY THIS LICENSE TEXT!
  */

 #include <config.h>
 #include <common.h>
 #include <div64.h>
 #include <errno.h>
 #include <image-sparse.h>
 #include <malloc.h>
 #include <part.h>
 #include <sparse_format.h>

 #include <linux/math64.h>

 typedef struct sparse_buffer {
 	void	*data;
 	u32	length;
 	u32	repeat;
 	u16	type;
 } sparse_buffer_t;

 static uint32_t last_offset;

 static unsigned int sparse_get_chunk_data_size(sparse_header_t *sparse,
 					       chunk_header_t *chunk)
 {
 	return chunk->total_sz - sparse->chunk_hdr_sz;
 }

 static unsigned int sparse_block_size_to_storage(unsigned int size,
 						 sparse_storage_t *storage,
 						 sparse_header_t *sparse)
 {
 	return (unsigned int)lldiv((uint64_t)size * sparse->blk_sz,
 				   storage->block_sz);
 }

 static bool sparse_chunk_has_buffer(chunk_header_t *chunk)
 {
 	switch (chunk->chunk_type) {
 	case CHUNK_TYPE_RAW:
 	case CHUNK_TYPE_FILL:
 		return true;

 	default:
 		return false;
 	}
 }

 static sparse_header_t *sparse_parse_header(void **data)
 {
 	/* Read and skip over sparse image header */
 	sparse_header_t *sparse_header = (sparse_header_t *) *data;

 	*data += sparse_header->file_hdr_sz;

 	debug("=== Sparse Image Header ===\n");
 	debug("magic: 0x%x\n", sparse_header->magic);
 	debug("major_version: 0x%x\n", sparse_header->major_version);
 	debug("minor_version: 0x%x\n", sparse_header->minor_version);
 	debug("file_hdr_sz: %d\n", sparse_header->file_hdr_sz);
 	debug("chunk_hdr_sz: %d\n", sparse_header->chunk_hdr_sz);
 	debug("blk_sz: %d\n", sparse_header->blk_sz);
 	debug("total_blks: %d\n", sparse_header->total_blks);
 	debug("total_chunks: %d\n", sparse_header->total_chunks);

 	return sparse_header;
 }

 static int sparse_parse_fill_chunk(sparse_header_t *sparse,
 				   chunk_header_t *chunk)
 {
 	unsigned int chunk_data_sz = sparse_get_chunk_data_size(sparse, chunk);

 	if (chunk_data_sz != sizeof(uint32_t))
 		return -EINVAL;

 	return 0;
 }

 static int sparse_parse_raw_chunk(sparse_header_t *sparse,
 				  chunk_header_t *chunk)
 {
 	unsigned int chunk_data_sz = sparse_get_chunk_data_size(sparse, chunk);

 	/* Check if the data size is a multiple of the main block size */
 	if (chunk_data_sz % sparse->blk_sz)
 		return -EINVAL;

 	/* Check that the chunk size is consistent */
 	if ((chunk_data_sz / sparse->blk_sz) != chunk->chunk_sz)
 		return -EINVAL;

 	return 0;
 }

 static chunk_header_t *sparse_parse_chunk(sparse_header_t *sparse,
 					  void **image)
 {
 	chunk_header_t *chunk = (chunk_header_t *) *image;
 	int ret;

 	debug("=== Chunk Header ===\n");
 	debug("chunk_type: 0x%x\n", chunk->chunk_type);
 	debug("chunk_data_sz: 0x%x\n", chunk->chunk_sz);
 	debug("total_size: 0x%x\n", chunk->total_sz);

 	switch (chunk->chunk_type) {
 	case CHUNK_TYPE_RAW:
 		ret = sparse_parse_raw_chunk(sparse, chunk);
 		if (ret)
 			return NULL;
 		break;

 	case CHUNK_TYPE_FILL:
 		ret = sparse_parse_fill_chunk(sparse, chunk);
 		if (ret)
 			return NULL;
 		break;

 	case CHUNK_TYPE_DONT_CARE:
 	case CHUNK_TYPE_CRC32:
 		debug("Ignoring chunk\n");
 		break;

 	default:
 		printf("%s: Unknown chunk type: %x\n", __func__,
 		       chunk->chunk_type);
 		return NULL;
 	}

 	*image += sparse->chunk_hdr_sz;

 	return chunk;
 }

 static int sparse_get_fill_buffer(sparse_header_t *sparse,
 				  chunk_header_t *chunk,
 				  sparse_buffer_t *buffer,
 				  unsigned int blk_sz,
 				  void *data)
 {
 	int i;

 	buffer->type = CHUNK_TYPE_FILL;

 	/*
 	 * We create a buffer of one block, and ask it to be
 	 * repeated as many times as needed.
 	 */
 	buffer->length = blk_sz;
 	buffer->repeat = (chunk->chunk_sz * sparse->blk_sz) / blk_sz;

 	buffer->data = memalign(ARCH_DMA_MINALIGN,
 				ROUNDUP(blk_sz,
 					ARCH_DMA_MINALIGN));
 	if (!buffer->data)
 		return -ENOMEM;

 	for (i = 0; i < (buffer->length / sizeof(uint32_t)); i++)
 		((uint32_t *)buffer->data)[i] = *(uint32_t *)(data);

 	return 0;
 }

 static int sparse_get_raw_buffer(sparse_header_t *sparse,
 				 chunk_header_t *chunk,
 				 sparse_buffer_t *buffer,
 				 unsigned int blk_sz,
 				 void *data)
 {
 	unsigned int chunk_data_sz = sparse_get_chunk_data_size(sparse, chunk);

 	buffer->type = CHUNK_TYPE_RAW;
 	buffer->length = chunk_data_sz;
 	buffer->data = data;
 	buffer->repeat = 1;

 	return 0;
 }

 static sparse_buffer_t *sparse_get_data_buffer(sparse_header_t *sparse,
 					       chunk_header_t *chunk,
 					       unsigned int blk_sz,
 					       void **image)
 {
 	unsigned int chunk_data_sz = sparse_get_chunk_data_size(sparse, chunk);
 	sparse_buffer_t *buffer;
 	void *data = *image;
 	int ret;

 	*image += chunk_data_sz;

 	if (!sparse_chunk_has_buffer(chunk))
 		return NULL;

 	buffer = calloc(sizeof(sparse_buffer_t), 1);
 	if (!buffer)
 		return NULL;

 	switch (chunk->chunk_type) {
 	case CHUNK_TYPE_RAW:
 		ret = sparse_get_raw_buffer(sparse, chunk, buffer, blk_sz,
 					    data);
 		if (ret)
 			return NULL;
 		break;

 	case CHUNK_TYPE_FILL:
 		ret = sparse_get_fill_buffer(sparse, chunk, buffer, blk_sz,
 					     data);
 		if (ret)
 			return NULL;
 		break;

 	default:
 		return NULL;
 	}

 	debug("=== Buffer ===\n");
 	debug("length: 0x%x\n", buffer->length);
 	debug("repeat: 0x%x\n", buffer->repeat);
 	debug("type: 0x%x\n", buffer->type);
 	debug("data: 0x%p\n", buffer->data);

 	return buffer;
 }

 static void sparse_put_data_buffer(sparse_buffer_t *buffer)
 {
 	if (buffer->type == CHUNK_TYPE_FILL)
 		free(buffer->data);

 	free(buffer);
 }

 int store_sparse_image(sparse_storage_t *storage, void *storage_priv,
 		       unsigned int session_id, void *data)
 {
 	unsigned int chunk, offset;
 	sparse_header_t *sparse_header;
 	chunk_header_t *chunk_header;
 	sparse_buffer_t *buffer;
 	uint32_t start;
 	uint32_t total_blocks = 0;
 	int i;

 	debug("=== Storage ===\n");
 	debug("name: %s\n", storage->name);
 	debug("block_size: 0x%x\n", storage->block_sz);
 	debug("start: 0x%x\n", storage->start);
 	debug("size: 0x%x\n", storage->size);
 	debug("write: 0x%p\n", storage->write);
 	debug("priv: 0x%p\n", storage_priv);

 	sparse_header = sparse_parse_header(&data);
 	if (!sparse_header) {
 		printf("sparse header issue\n");
 		return -EINVAL;
 	}

 	/*
 	 * Verify that the sparse block size is a multiple of our
 	 * storage backend block size
 	 */
 	div_u64_rem(sparse_header->blk_sz, storage->block_sz, &offset);
 	if (offset) {
 		printf("%s: Sparse image block size issue [%u]\n",
 		       __func__, sparse_header->blk_sz);
 		return -EINVAL;
 	}

 	/*
 	 * If it's a new flashing session, start at the beginning of
 	 * the partition. If not, then simply resume where we were.
 	 */
 	if (session_id > 0)
 		start = last_offset;
 	else
 		start = storage->start;

 	printf("Flashing sparse image on partition %s at offset 0x%x (ID: %d)\n",
 	       storage->name, start * storage->block_sz, session_id);

 	/* Start processing chunks */
 	for (chunk = 0; chunk < sparse_header->total_chunks; chunk++) {
 		uint32_t blkcnt;

 		chunk_header = sparse_parse_chunk(sparse_header, &data);
 		if (!chunk_header) {
 			printf("Unknown chunk type");
 			return -EINVAL;
 		}

 		/*
 		 * If we have a DONT_CARE type, just skip the blocks
 		 * and go on parsing the rest of the chunks
 		 */
 		if (chunk_header->chunk_type == CHUNK_TYPE_DONT_CARE) {
 			blkcnt = sparse_block_size_to_storage(chunk_header->chunk_sz,
 							      storage,
 							      sparse_header);
 #ifdef CONFIG_FASTBOOT_FLASH_MMC_DEV
 			total_blocks += blkcnt;
 #endif
 			continue;
 		}

 		/* Retrieve the buffer we're going to write */
 		buffer = sparse_get_data_buffer(sparse_header, chunk_header,
 						storage->block_sz, &data);
 		if (!buffer)
 			continue;

 		blkcnt = (buffer->length / storage->block_sz) * buffer->repeat;

 		if ((start + total_blocks + blkcnt) >
 		    (storage->start + storage->size)) {
 			printf("%s: Request would exceed partition size!\n",
 			       __func__);
 			return -EINVAL;
 		}

 		for (i = 0; i < buffer->repeat; i++) {
 			unsigned long buffer_blk_cnt;
 			int ret;

 			buffer_blk_cnt = buffer->length / storage->block_sz;

 			ret = storage->write(storage, storage_priv,
 					     start + total_blocks,
 					     buffer_blk_cnt,
 					     buffer->data);
 			if (ret < 0) {
 				printf("%s: Write %d failed %d\n",
 				       __func__, i, ret);
 				return ret;
 			}

 			total_blocks += ret;
 		}

 		sparse_put_data_buffer(buffer);
 	}

 	debug("Wrote %d blocks, expected to write %d blocks\n",
 	      total_blocks,
 	      sparse_block_size_to_storage(sparse_header->total_blks,
 					   storage, sparse_header));
 	printf("........ wrote %d blocks to '%s'\n", total_blocks,
 	       storage->name);

 	if (total_blocks !=
 	    sparse_block_size_to_storage(sparse_header->total_blks,
 					 storage, sparse_header)) {
 		printf("sparse image write failure\n");
 		return -EIO;
 	}

 	last_offset = start + total_blocks;

 	return 0;
 }
	/*
	* Copyright (c) 2009, Google Inc.
	* All rights reserved.
	*
	* Copyright (c) 2009-2014, The Linux Foundation. All rights reserved.
	* Portions Copyright 2014 Broadcom Corporation.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are met:
	* * Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* * Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	* * Neither the name of The Linux Foundation nor
	* the names of its contributors may be used to endorse or promote
	* products derived from this software without specific prior written
	* permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
	* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
	* NON-INFRINGEMENT ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
	* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
	* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
	* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
	* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
	* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
	* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*
	* NOTE:
	* Although it is very similar, this license text is not identical
	* to the "BSD-3-Clause", therefore, DO NOT MODIFY THIS LICENSE TEXT!
	*/

	#include <config.h>
	#include <common.h>
	#include <div64.h>
	#include <errno.h>
	#include <image-sparse.h>
	#include <malloc.h>
	#include <part.h>
	#include <sparse_format.h>

	#include <linux/math64.h>

	typedef struct sparse_buffer {
	void *data;
	u32 length;
	u32 repeat;
	u16 type;
	} sparse_buffer_t;

	static uint32_t last_offset;

	static unsigned int sparse_get_chunk_data_size(sparse_header_t *sparse,
	chunk_header_t *chunk)
	{
	return chunk->total_sz - sparse->chunk_hdr_sz;
	}

	static unsigned int sparse_block_size_to_storage(unsigned int size,
	sparse_storage_t *storage,
	sparse_header_t *sparse)
	{
	return (unsigned int)lldiv((uint64_t)size * sparse->blk_sz,
	storage->block_sz);
	}

	static bool sparse_chunk_has_buffer(chunk_header_t *chunk)
	{
	switch (chunk->chunk_type) {
	case CHUNK_TYPE_RAW:
	case CHUNK_TYPE_FILL:
	return true;

	default:
	return false;
	}
	}

	static sparse_header_t sparse_parse_header(void *data)
	{
	/* Read and skip over sparse image header */
	sparse_header_t sparse_header = (sparse_header_t ) *data;

	*data += sparse_header->file_hdr_sz;

	debug("=== Sparse Image Header ===\n");
	debug("magic: 0x%x\n", sparse_header->magic);
	debug("major_version: 0x%x\n", sparse_header->major_version);
	debug("minor_version: 0x%x\n", sparse_header->minor_version);
	debug("file_hdr_sz: %d\n", sparse_header->file_hdr_sz);
	debug("chunk_hdr_sz: %d\n", sparse_header->chunk_hdr_sz);
	debug("blk_sz: %d\n", sparse_header->blk_sz);
	debug("total_blks: %d\n", sparse_header->total_blks);
	debug("total_chunks: %d\n", sparse_header->total_chunks);

	return sparse_header;
	}

	static int sparse_parse_fill_chunk(sparse_header_t *sparse,
	chunk_header_t *chunk)
	{
	unsigned int chunk_data_sz = sparse_get_chunk_data_size(sparse, chunk);

	if (chunk_data_sz != sizeof(uint32_t))
	return -EINVAL;

	return 0;
	}

	static int sparse_parse_raw_chunk(sparse_header_t *sparse,
	chunk_header_t *chunk)
	{
	unsigned int chunk_data_sz = sparse_get_chunk_data_size(sparse, chunk);

	/* Check if the data size is a multiple of the main block size */
	if (chunk_data_sz % sparse->blk_sz)
	return -EINVAL;

	/* Check that the chunk size is consistent */
	if ((chunk_data_sz / sparse->blk_sz) != chunk->chunk_sz)
	return -EINVAL;

	return 0;
	}

	static chunk_header_t sparse_parse_chunk(sparse_header_t sparse,
	void **image)
	{
	chunk_header_t chunk = (chunk_header_t ) *image;
	int ret;

	debug("=== Chunk Header ===\n");
	debug("chunk_type: 0x%x\n", chunk->chunk_type);
	debug("chunk_data_sz: 0x%x\n", chunk->chunk_sz);
	debug("total_size: 0x%x\n", chunk->total_sz);

	switch (chunk->chunk_type) {
	case CHUNK_TYPE_RAW:
	ret = sparse_parse_raw_chunk(sparse, chunk);
	if (ret)
	return NULL;
	break;

	case CHUNK_TYPE_FILL:
	ret = sparse_parse_fill_chunk(sparse, chunk);
	if (ret)
	return NULL;
	break;

	case CHUNK_TYPE_DONT_CARE:
	case CHUNK_TYPE_CRC32:
	debug("Ignoring chunk\n");
	break;

	default:
	printf("%s: Unknown chunk type: %x\n", __func__,
	chunk->chunk_type);
	return NULL;
	}

	*image += sparse->chunk_hdr_sz;

	return chunk;
	}

	static int sparse_get_fill_buffer(sparse_header_t *sparse,
	chunk_header_t *chunk,
	sparse_buffer_t *buffer,
	unsigned int blk_sz,
	void *data)
	{
	int i;

	buffer->type = CHUNK_TYPE_FILL;

	/*
	* We create a buffer of one block, and ask it to be
	* repeated as many times as needed.
	*/
	buffer->length = blk_sz;
	buffer->repeat = (chunk->chunk_sz * sparse->blk_sz) / blk_sz;

	buffer->data = memalign(ARCH_DMA_MINALIGN,
	ROUNDUP(blk_sz,
	ARCH_DMA_MINALIGN));
	if (!buffer->data)
	return -ENOMEM;

	for (i = 0; i < (buffer->length / sizeof(uint32_t)); i++)
	((uint32_t )buffer->data)[i] = (uint32_t *)(data);

	return 0;
	}

	static int sparse_get_raw_buffer(sparse_header_t *sparse,
	chunk_header_t *chunk,
	sparse_buffer_t *buffer,
	unsigned int blk_sz,
	void *data)
	{
	unsigned int chunk_data_sz = sparse_get_chunk_data_size(sparse, chunk);

	buffer->type = CHUNK_TYPE_RAW;
	buffer->length = chunk_data_sz;
	buffer->data = data;
	buffer->repeat = 1;

	return 0;
	}

	static sparse_buffer_t sparse_get_data_buffer(sparse_header_t sparse,
	chunk_header_t *chunk,
	unsigned int blk_sz,
	void **image)
	{
	unsigned int chunk_data_sz = sparse_get_chunk_data_size(sparse, chunk);
	sparse_buffer_t *buffer;
	void data = image;
	int ret;

	*image += chunk_data_sz;

	if (!sparse_chunk_has_buffer(chunk))
	return NULL;

	buffer = calloc(sizeof(sparse_buffer_t), 1);
	if (!buffer)
	return NULL;

	switch (chunk->chunk_type) {
	case CHUNK_TYPE_RAW:
	ret = sparse_get_raw_buffer(sparse, chunk, buffer, blk_sz,
	data);
	if (ret)
	return NULL;
	break;

	case CHUNK_TYPE_FILL:
	ret = sparse_get_fill_buffer(sparse, chunk, buffer, blk_sz,
	data);
	if (ret)
	return NULL;
	break;

	default:
	return NULL;
	}

	debug("=== Buffer ===\n");
	debug("length: 0x%x\n", buffer->length);
	debug("repeat: 0x%x\n", buffer->repeat);
	debug("type: 0x%x\n", buffer->type);
	debug("data: 0x%p\n", buffer->data);

	return buffer;
	}

	static void sparse_put_data_buffer(sparse_buffer_t *buffer)
	{
	if (buffer->type == CHUNK_TYPE_FILL)
	free(buffer->data);

	free(buffer);
	}

	int store_sparse_image(sparse_storage_t storage, void storage_priv,
	unsigned int session_id, void *data)
	{
	unsigned int chunk, offset;
	sparse_header_t *sparse_header;
	chunk_header_t *chunk_header;
	sparse_buffer_t *buffer;
	uint32_t start;
	uint32_t total_blocks = 0;
	int i;

	debug("=== Storage ===\n");
	debug("name: %s\n", storage->name);
	debug("block_size: 0x%x\n", storage->block_sz);
	debug("start: 0x%x\n", storage->start);
	debug("size: 0x%x\n", storage->size);
	debug("write: 0x%p\n", storage->write);
	debug("priv: 0x%p\n", storage_priv);

	sparse_header = sparse_parse_header(&data);
	if (!sparse_header) {
	printf("sparse header issue\n");
	return -EINVAL;
	}

	/*
	* Verify that the sparse block size is a multiple of our
	* storage backend block size
	*/
	div_u64_rem(sparse_header->blk_sz, storage->block_sz, &offset);
	if (offset) {
	printf("%s: Sparse image block size issue [%u]\n",
	__func__, sparse_header->blk_sz);
	return -EINVAL;
	}

	/*
	* If it's a new flashing session, start at the beginning of
	* the partition. If not, then simply resume where we were.
	*/
	if (session_id > 0)
	start = last_offset;
	else
	start = storage->start;

	printf("Flashing sparse image on partition %s at offset 0x%x (ID: %d)\n",
	storage->name, start * storage->block_sz, session_id);

	/* Start processing chunks */
	for (chunk = 0; chunk < sparse_header->total_chunks; chunk++) {
	uint32_t blkcnt;

	chunk_header = sparse_parse_chunk(sparse_header, &data);
	if (!chunk_header) {
	printf("Unknown chunk type");
	return -EINVAL;
	}

	/*
	* If we have a DONT_CARE type, just skip the blocks
	* and go on parsing the rest of the chunks
	*/
	if (chunk_header->chunk_type == CHUNK_TYPE_DONT_CARE) {
	blkcnt = sparse_block_size_to_storage(chunk_header->chunk_sz,
	storage,
	sparse_header);
	#ifdef CONFIG_FASTBOOT_FLASH_MMC_DEV
	total_blocks += blkcnt;
	#endif
	continue;
	}

	/* Retrieve the buffer we're going to write */
	buffer = sparse_get_data_buffer(sparse_header, chunk_header,
	storage->block_sz, &data);
	if (!buffer)
	continue;

	blkcnt = (buffer->length / storage->block_sz) * buffer->repeat;

	if ((start + total_blocks + blkcnt) >
	(storage->start + storage->size)) {
	printf("%s: Request would exceed partition size!\n",
	__func__);
	return -EINVAL;
	}

	for (i = 0; i < buffer->repeat; i++) {
	unsigned long buffer_blk_cnt;
	int ret;

	buffer_blk_cnt = buffer->length / storage->block_sz;

	ret = storage->write(storage, storage_priv,
	start + total_blocks,
	buffer_blk_cnt,
	buffer->data);
	if (ret < 0) {
	printf("%s: Write %d failed %d\n",
	__func__, i, ret);
	return ret;
	}

	total_blocks += ret;
	}

	sparse_put_data_buffer(buffer);
	}

	debug("Wrote %d blocks, expected to write %d blocks\n",
	total_blocks,
	sparse_block_size_to_storage(sparse_header->total_blks,
	storage, sparse_header));
	printf("........ wrote %d blocks to '%s'\n", total_blocks,
	storage->name);

	if (total_blocks !=
	sparse_block_size_to_storage(sparse_header->total_blks,
	storage, sparse_header)) {
	printf("sparse image write failure\n");
	return -EIO;
	}

	last_offset = start + total_blocks;

	return 0;
	}