drivers/dfu/dfu_scsi.c - github/trini/u-boot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * DFU SCSI backend (based on MMC backend).
  *
  * Copyright (C) 2012 Samsung Electronics
  *   author: Lukasz Majewski <l.majewski@samsung.com>
  * Copyright (C) 2024 Linaro Ltd.
  */

 #include <log.h>
 #include <malloc.h>
 #include <errno.h>
 #include <div64.h>
 #include <dfu.h>
 #include <ext4fs.h>
 #include <fat.h>
 #include <scsi.h>
 #include <part.h>
 #include <command.h>
 #include <linux/printk.h>

 static unsigned char *dfu_file_buf;
 static u64 dfu_file_buf_len;
 static u64 dfu_file_buf_offset;

 #define scsi_get_blk_desc(dev) ((struct blk_desc *)dev_get_uclass_plat(dev))

 #define find_scsi_device(dev_num, scsi) blk_get_device(UCLASS_SCSI, dev_num, scsi)

 static int scsi_block_op(enum dfu_op op, struct dfu_entity *dfu, u64 offset, void *buf, long *len)
 {
 	struct udevice *scsi;
 	u32 blk_start, blk_count, n = 0;
 	int ret;

 	ret = find_scsi_device(dfu->data.scsi.lun, &scsi);
 	if (ret < 0) {
 		pr_err("Device scsi %d - not found!", dfu->data.scsi.lun);
 		return -ENODEV;
 	}

 	/*
 	 * We must ensure that we work in lba_blk_size chunks, so ALIGN
 	 * this value.
 	 */
 	*len = ALIGN(*len, dfu->data.scsi.lba_blk_size);

 	blk_start = dfu->data.scsi.lba_start + (u32)lldiv(offset, dfu->data.scsi.lba_blk_size);
 	blk_count = *len / dfu->data.scsi.lba_blk_size;
 	if (blk_start + blk_count > dfu->data.scsi.lba_start + dfu->data.scsi.lba_size) {
 		puts("Request would exceed designated area!\n");
 		return -EINVAL;
 	}

 	debug("%s: %s dev: %d start: %d cnt: %d buf: 0x%p\n", __func__,
 	      op == DFU_OP_READ ? "scsi READ" : "scsi WRITE", dfu->data.scsi.lun, blk_start,
 	      blk_count, buf);
 	switch (op) {
 	case DFU_OP_READ:
 		n = blk_dread(scsi_get_blk_desc(scsi), blk_start, blk_count, buf);
 		break;
 	case DFU_OP_WRITE:
 		n = blk_dwrite(scsi_get_blk_desc(scsi), blk_start, blk_count, buf);
 		break;
 	default:
 		pr_err("Operation not supported\n");
 	}

 	if (n != blk_count) {
 		pr_err("scsi block operation failed");
 		return -EIO;
 	}

 	return 0;
 }

 static int scsi_file_op(enum dfu_op op, struct dfu_entity *dfu, u64 offset, void *buf, u64 *len)
 {
 	char dev_part_str[8];
 	int ret;
 	int fstype;
 	loff_t size = 0;

 	switch (dfu->layout) {
 	case DFU_FS_FAT:
 		fstype = FS_TYPE_FAT;
 		break;
 	case DFU_FS_EXT4:
 		fstype = FS_TYPE_EXT;
 		break;
 	case DFU_SKIP:
 		return 0;
 	default:
 		printf("%s: Layout (%s) not (yet) supported!\n", __func__,
 		       dfu_get_layout(dfu->layout));
 		return -1;
 	}

 	snprintf(dev_part_str, sizeof(dev_part_str), "%d:%d", dfu->data.scsi.dev,
 		 dfu->data.scsi.part);

 	ret = fs_set_blk_dev("scsi", dev_part_str, fstype);
 	if (ret) {
 		puts("dfu: fs_set_blk_dev error!\n");
 		return ret;
 	}

 	switch (op) {
 	case DFU_OP_READ:
 		ret = fs_read(dfu->name, (size_t)buf, offset, *len, &size);
 		if (ret) {
 			puts("dfu: fs_read error!\n");
 			return ret;
 		}
 		*len = size;
 		break;
 	case DFU_OP_WRITE:
 		ret = fs_write(dfu->name, (size_t)buf, offset, *len, &size);
 		if (ret) {
 			puts("dfu: fs_write error!\n");
 			return ret;
 		}
 		break;
 	case DFU_OP_SIZE:
 		ret = fs_size(dfu->name, &size);
 		if (ret) {
 			puts("dfu: fs_size error!\n");
 			return ret;
 		}
 		*len = size;
 		break;
 	default:
 		return -1;
 	}

 	return ret;
 }

 static int scsi_file_buf_write(struct dfu_entity *dfu, u64 offset, void *buf, long *len)
 {
 	int ret = 0;

 	if (offset == 0) {
 		dfu_file_buf_len = 0;
 		dfu_file_buf_offset = 0;
 	}

 	/* Add to the current buffer. */
 	if (dfu_file_buf_len + *len > CONFIG_SYS_DFU_MAX_FILE_SIZE)
 		*len = CONFIG_SYS_DFU_MAX_FILE_SIZE - dfu_file_buf_len;
 	memcpy(dfu_file_buf + dfu_file_buf_len, buf, *len);
 	dfu_file_buf_len += *len;

 	if (dfu_file_buf_len == CONFIG_SYS_DFU_MAX_FILE_SIZE) {
 		ret = scsi_file_op(DFU_OP_WRITE, dfu, dfu_file_buf_offset, dfu_file_buf,
 				   &dfu_file_buf_len);
 		dfu_file_buf_offset += dfu_file_buf_len;
 		dfu_file_buf_len = 0;
 	}

 	return ret;
 }

 static int scsi_file_buf_write_finish(struct dfu_entity *dfu)
 {
 	int ret = scsi_file_op(DFU_OP_WRITE, dfu, dfu_file_buf_offset, dfu_file_buf,
 			       &dfu_file_buf_len);

 	/* Now that we're done */
 	dfu_file_buf_len = 0;
 	dfu_file_buf_offset = 0;

 	return ret;
 }

 int dfu_write_medium_scsi(struct dfu_entity *dfu, u64 offset, void *buf, long *len)
 {
 	int ret = -1;

 	switch (dfu->layout) {
 	case DFU_RAW_ADDR:
 		ret = scsi_block_op(DFU_OP_WRITE, dfu, offset, buf, len);
 		break;
 	case DFU_FS_FAT:
 	case DFU_FS_EXT4:
 		ret = scsi_file_buf_write(dfu, offset, buf, len);
 		break;
 	case DFU_SCRIPT:
 		ret = run_command_list(buf, *len, 0);
 		break;
 	case DFU_SKIP:
 		ret = 0;
 		break;
 	default:
 		printf("%s: Layout (%s) not (yet) supported!\n", __func__,
 		       dfu_get_layout(dfu->layout));
 	}

 	return ret;
 }

 int dfu_flush_medium_scsi(struct dfu_entity *dfu)
 {
 	int ret = 0;

 	switch (dfu->layout) {
 	case DFU_FS_FAT:
 	case DFU_FS_EXT4:
 		ret = scsi_file_buf_write_finish(dfu);
 		break;
 	case DFU_SCRIPT:
 		/* script may have changed the dfu_alt_info */
 		dfu_reinit_needed = true;
 		break;
 	case DFU_RAW_ADDR:
 	case DFU_SKIP:
 		break;
 	default:
 		printf("%s: Layout (%s) not (yet) supported!\n", __func__,
 		       dfu_get_layout(dfu->layout));
 	}

 	return ret;
 }

 int dfu_get_medium_size_scsi(struct dfu_entity *dfu, u64 *size)
 {
 	int ret;

 	switch (dfu->layout) {
 	case DFU_RAW_ADDR:
 		*size = dfu->data.scsi.lba_size * dfu->data.scsi.lba_blk_size;
 		return 0;
 	case DFU_FS_FAT:
 	case DFU_FS_EXT4:
 		ret = scsi_file_op(DFU_OP_SIZE, dfu, 0, NULL, size);
 		if (ret < 0)
 			return ret;
 		return 0;
 	case DFU_SCRIPT:
 	case DFU_SKIP:
 		return 0;
 	default:
 		printf("%s: Layout (%s) not (yet) supported!\n", __func__,
 		       dfu_get_layout(dfu->layout));
 		return -1;
 	}
 }

 static int scsi_file_buf_read(struct dfu_entity *dfu, u64 offset, void *buf, long *len)
 {
 	int ret;

 	if (offset == 0 || offset >= dfu_file_buf_offset + dfu_file_buf_len ||
 	    offset + *len < dfu_file_buf_offset) {
 		u64 file_len = CONFIG_SYS_DFU_MAX_FILE_SIZE;

 		ret = scsi_file_op(DFU_OP_READ, dfu, offset, dfu_file_buf, &file_len);
 		if (ret < 0)
 			return ret;
 		dfu_file_buf_len = file_len;
 		dfu_file_buf_offset = offset;
 	}
 	if (offset + *len > dfu_file_buf_offset + dfu_file_buf_len)
 		return -EINVAL;

 	/* Add to the current buffer. */
 	memcpy(buf, dfu_file_buf + offset - dfu_file_buf_offset, *len);

 	return 0;
 }

 int dfu_read_medium_scsi(struct dfu_entity *dfu, u64 offset, void *buf, long *len)
 {
 	int ret = -1;

 	switch (dfu->layout) {
 	case DFU_RAW_ADDR:
 		ret = scsi_block_op(DFU_OP_READ, dfu, offset, buf, len);
 		break;
 	case DFU_FS_FAT:
 	case DFU_FS_EXT4:
 		ret = scsi_file_buf_read(dfu, offset, buf, len);
 		break;
 	default:
 		printf("%s: Layout (%s) not (yet) supported!\n", __func__,
 		       dfu_get_layout(dfu->layout));
 	}

 	return ret;
 }

 void dfu_free_entity_scsi(struct dfu_entity *dfu)
 {
 	if (dfu_file_buf) {
 		free(dfu_file_buf);
 		dfu_file_buf = NULL;
 	}
 }

 /*
  * @param s Parameter string containing space-separated arguments:
  *	1st:
  *		raw	(raw read/write)
  *		fat	(files)
  *		ext4	(^)
  *		part	(partition image)
  *	2nd and 3rd:
  *		lba_start and lba_size, for raw write
  *		scsi_dev and scsi_part, for filesystems and part
  */
 int dfu_fill_entity_scsi(struct dfu_entity *dfu, char *devstr, char **argv, int argc)
 {
 	const char *entity_type;
 	ssize_t second_arg;
 	ssize_t third_arg = -1;
 	struct udevice *scsi;
 	struct blk_desc *blk_dev;
 	int ret;
 	char *s;

 	if (argc < 2) {
 		pr_err("Need at least one argument\n");
 		return -EINVAL;
 	}

 	dfu->data.scsi.lun = dectoul(devstr, &s);
 	if (*s)
 		return -EINVAL;

 	entity_type = argv[0];
 	/*
 	 * Base 0 means we'll accept (prefixed with 0x or 0) base 16, 8,
 	 * with default 10.
 	 */
 	second_arg = simple_strtol(argv[1], &s, 0);
 	if (*s)
 		return -EINVAL;
 	if (argc >= 3) {
 		third_arg = simple_strtoul(argv[2], &s, 0);
 		if (*s)
 			return -EINVAL;
 	}

 	if (scsi_scan(false)) {
 		pr_err("Couldn't init scsi device.\n");
 		return -ENODEV;
 	}

 	ret = find_scsi_device(dfu->data.scsi.lun, &scsi);
 	if (ret < 0) {
 		pr_err("Couldn't find scsi device no. %d.\n", dfu->data.scsi.lun);
 		return -ENODEV;
 	}

 	blk_dev = scsi_get_blk_desc(scsi);
 	if (!blk_dev) {
 		pr_err("Couldn't get block device for scsi device no. %d.\n", dfu->data.scsi.lun);
 		return -ENODEV;
 	}

 	/* if it's NOT a raw write */
 	if (strcmp(entity_type, "raw")) {
 		dfu->data.scsi.dev = (second_arg != -1) ? second_arg : dfu->data.scsi.lun;
 		dfu->data.scsi.part = third_arg;
 	}

 	if (!strcmp(entity_type, "raw")) {
 		dfu->layout = DFU_RAW_ADDR;
 		dfu->data.scsi.lba_start = second_arg;
 		if (third_arg < 0) {
 			pr_err("raw requires two arguments\n");
 			return -EINVAL;
 		}
 		dfu->data.scsi.lba_size = third_arg;
 		dfu->data.scsi.lba_blk_size = blk_dev->blksz;

 		/*
 		 * In case the size is zero (i.e. scsi raw 0x10 0),
 		 * assume the user intends to use whole device.
 		 */
 		if (third_arg == 0)
 			dfu->data.scsi.lba_size = blk_dev->lba;

 	} else if (!strcmp(entity_type, "part")) {
 		struct disk_partition partinfo;
 		int scsipart = second_arg;

 		if (third_arg >= 0) {
 			pr_err("part only accepts one argument\n");
 			return -EINVAL;
 		}

 		if (part_get_info(blk_dev, scsipart, &partinfo) != 0) {
 			pr_err("Couldn't find part #%d on scsi device #%d\n", scsipart,
 			       dfu->data.scsi.lun);
 			return -ENODEV;
 		}

 		dfu->layout = DFU_RAW_ADDR;
 		dfu->data.scsi.lba_start = partinfo.start;
 		dfu->data.scsi.lba_size = partinfo.size;
 		dfu->data.scsi.lba_blk_size = partinfo.blksz;
 	} else if (!strcmp(entity_type, "fat")) {
 		dfu->layout = DFU_FS_FAT;
 	} else if (!strcmp(entity_type, "ext4")) {
 		dfu->layout = DFU_FS_EXT4;
 	} else if (!strcmp(entity_type, "skip")) {
 		dfu->layout = DFU_SKIP;
 	} else if (!strcmp(entity_type, "script")) {
 		dfu->layout = DFU_SCRIPT;
 	} else {
 		pr_err("Memory layout (%s) not supported!\n", entity_type);
 		return -ENODEV;
 	}

 	dfu->dev_type = DFU_DEV_SCSI;
 	dfu->get_medium_size = dfu_get_medium_size_scsi;
 	dfu->read_medium = dfu_read_medium_scsi;
 	dfu->write_medium = dfu_write_medium_scsi;
 	dfu->flush_medium = dfu_flush_medium_scsi;
 	dfu->inited = 0;
 	dfu->free_entity = dfu_free_entity_scsi;

 	/* Check if file buffer is ready */
 	if (!dfu_file_buf) {
 		dfu_file_buf = memalign(CONFIG_SYS_CACHELINE_SIZE, CONFIG_SYS_DFU_MAX_FILE_SIZE);
 		if (!dfu_file_buf) {
 			pr_err("Could not memalign 0x%x bytes\n", CONFIG_SYS_DFU_MAX_FILE_SIZE);
 			return -ENOMEM;
 		}
 	}

 	return 0;
 }
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* DFU SCSI backend (based on MMC backend).
	*
	* Copyright (C) 2012 Samsung Electronics
	* author: Lukasz Majewski <l.majewski@samsung.com>
	* Copyright (C) 2024 Linaro Ltd.
	*/

	#include <log.h>
	#include <malloc.h>
	#include <errno.h>
	#include <div64.h>
	#include <dfu.h>
	#include <ext4fs.h>
	#include <fat.h>
	#include <scsi.h>
	#include <part.h>
	#include <command.h>
	#include <linux/printk.h>

	static unsigned char *dfu_file_buf;
	static u64 dfu_file_buf_len;
	static u64 dfu_file_buf_offset;

	#define scsi_get_blk_desc(dev) ((struct blk_desc *)dev_get_uclass_plat(dev))

	#define find_scsi_device(dev_num, scsi) blk_get_device(UCLASS_SCSI, dev_num, scsi)

	static int scsi_block_op(enum dfu_op op, struct dfu_entity dfu, u64 offset, void buf, long *len)
	{
	struct udevice *scsi;
	u32 blk_start, blk_count, n = 0;
	int ret;

	ret = find_scsi_device(dfu->data.scsi.lun, &scsi);
	if (ret < 0) {
	pr_err("Device scsi %d - not found!", dfu->data.scsi.lun);
	return -ENODEV;
	}

	/*
	* We must ensure that we work in lba_blk_size chunks, so ALIGN
	* this value.
	*/
	len = ALIGN(len, dfu->data.scsi.lba_blk_size);

	blk_start = dfu->data.scsi.lba_start + (u32)lldiv(offset, dfu->data.scsi.lba_blk_size);
	blk_count = *len / dfu->data.scsi.lba_blk_size;
	if (blk_start + blk_count > dfu->data.scsi.lba_start + dfu->data.scsi.lba_size) {
	puts("Request would exceed designated area!\n");
	return -EINVAL;
	}

	debug("%s: %s dev: %d start: %d cnt: %d buf: 0x%p\n", __func__,
	op == DFU_OP_READ ? "scsi READ" : "scsi WRITE", dfu->data.scsi.lun, blk_start,
	blk_count, buf);
	switch (op) {
	case DFU_OP_READ:
	n = blk_dread(scsi_get_blk_desc(scsi), blk_start, blk_count, buf);
	break;
	case DFU_OP_WRITE:
	n = blk_dwrite(scsi_get_blk_desc(scsi), blk_start, blk_count, buf);
	break;
	default:
	pr_err("Operation not supported\n");
	}

	if (n != blk_count) {
	pr_err("scsi block operation failed");
	return -EIO;
	}

	return 0;
	}

	static int scsi_file_op(enum dfu_op op, struct dfu_entity dfu, u64 offset, void buf, u64 *len)
	{
	char dev_part_str[8];
	int ret;
	int fstype;
	loff_t size = 0;

	switch (dfu->layout) {
	case DFU_FS_FAT:
	fstype = FS_TYPE_FAT;
	break;
	case DFU_FS_EXT4:
	fstype = FS_TYPE_EXT;
	break;
	case DFU_SKIP:
	return 0;
	default:
	printf("%s: Layout (%s) not (yet) supported!\n", __func__,
	dfu_get_layout(dfu->layout));
	return -1;
	}

	snprintf(dev_part_str, sizeof(dev_part_str), "%d:%d", dfu->data.scsi.dev,
	dfu->data.scsi.part);

	ret = fs_set_blk_dev("scsi", dev_part_str, fstype);
	if (ret) {
	puts("dfu: fs_set_blk_dev error!\n");
	return ret;
	}

	switch (op) {
	case DFU_OP_READ:
	ret = fs_read(dfu->name, (size_t)buf, offset, *len, &size);
	if (ret) {
	puts("dfu: fs_read error!\n");
	return ret;
	}
	*len = size;
	break;
	case DFU_OP_WRITE:
	ret = fs_write(dfu->name, (size_t)buf, offset, *len, &size);
	if (ret) {
	puts("dfu: fs_write error!\n");
	return ret;
	}
	break;
	case DFU_OP_SIZE:
	ret = fs_size(dfu->name, &size);
	if (ret) {
	puts("dfu: fs_size error!\n");
	return ret;
	}
	*len = size;
	break;
	default:
	return -1;
	}

	return ret;
	}

	static int scsi_file_buf_write(struct dfu_entity dfu, u64 offset, void buf, long *len)
	{
	int ret = 0;

	if (offset == 0) {
	dfu_file_buf_len = 0;
	dfu_file_buf_offset = 0;
	}

	/* Add to the current buffer. */
	if (dfu_file_buf_len + *len > CONFIG_SYS_DFU_MAX_FILE_SIZE)
	*len = CONFIG_SYS_DFU_MAX_FILE_SIZE - dfu_file_buf_len;
	memcpy(dfu_file_buf + dfu_file_buf_len, buf, *len);
	dfu_file_buf_len += *len;

	if (dfu_file_buf_len == CONFIG_SYS_DFU_MAX_FILE_SIZE) {
	ret = scsi_file_op(DFU_OP_WRITE, dfu, dfu_file_buf_offset, dfu_file_buf,
	&dfu_file_buf_len);
	dfu_file_buf_offset += dfu_file_buf_len;
	dfu_file_buf_len = 0;
	}

	return ret;
	}

	static int scsi_file_buf_write_finish(struct dfu_entity *dfu)
	{
	int ret = scsi_file_op(DFU_OP_WRITE, dfu, dfu_file_buf_offset, dfu_file_buf,
	&dfu_file_buf_len);

	/* Now that we're done */
	dfu_file_buf_len = 0;
	dfu_file_buf_offset = 0;

	return ret;
	}

	int dfu_write_medium_scsi(struct dfu_entity dfu, u64 offset, void buf, long *len)
	{
	int ret = -1;

	switch (dfu->layout) {
	case DFU_RAW_ADDR:
	ret = scsi_block_op(DFU_OP_WRITE, dfu, offset, buf, len);
	break;
	case DFU_FS_FAT:
	case DFU_FS_EXT4:
	ret = scsi_file_buf_write(dfu, offset, buf, len);
	break;
	case DFU_SCRIPT:
	ret = run_command_list(buf, *len, 0);
	break;
	case DFU_SKIP:
	ret = 0;
	break;
	default:
	printf("%s: Layout (%s) not (yet) supported!\n", __func__,
	dfu_get_layout(dfu->layout));
	}

	return ret;
	}

	int dfu_flush_medium_scsi(struct dfu_entity *dfu)
	{
	int ret = 0;

	switch (dfu->layout) {
	case DFU_FS_FAT:
	case DFU_FS_EXT4:
	ret = scsi_file_buf_write_finish(dfu);
	break;
	case DFU_SCRIPT:
	/* script may have changed the dfu_alt_info */
	dfu_reinit_needed = true;
	break;
	case DFU_RAW_ADDR:
	case DFU_SKIP:
	break;
	default:
	printf("%s: Layout (%s) not (yet) supported!\n", __func__,
	dfu_get_layout(dfu->layout));
	}

	return ret;
	}

	int dfu_get_medium_size_scsi(struct dfu_entity dfu, u64 size)
	{
	int ret;

	switch (dfu->layout) {
	case DFU_RAW_ADDR:
	size = dfu->data.scsi.lba_size dfu->data.scsi.lba_blk_size;
	return 0;
	case DFU_FS_FAT:
	case DFU_FS_EXT4:
	ret = scsi_file_op(DFU_OP_SIZE, dfu, 0, NULL, size);
	if (ret < 0)
	return ret;
	return 0;
	case DFU_SCRIPT:
	case DFU_SKIP:
	return 0;
	default:
	printf("%s: Layout (%s) not (yet) supported!\n", __func__,
	dfu_get_layout(dfu->layout));
	return -1;
	}
	}

	static int scsi_file_buf_read(struct dfu_entity dfu, u64 offset, void buf, long *len)
	{
	int ret;

	if (offset == 0 \|\| offset >= dfu_file_buf_offset + dfu_file_buf_len \|\|
	offset + *len < dfu_file_buf_offset) {
	u64 file_len = CONFIG_SYS_DFU_MAX_FILE_SIZE;

	ret = scsi_file_op(DFU_OP_READ, dfu, offset, dfu_file_buf, &file_len);
	if (ret < 0)
	return ret;
	dfu_file_buf_len = file_len;
	dfu_file_buf_offset = offset;
	}
	if (offset + *len > dfu_file_buf_offset + dfu_file_buf_len)
	return -EINVAL;

	/* Add to the current buffer. */
	memcpy(buf, dfu_file_buf + offset - dfu_file_buf_offset, *len);

	return 0;
	}

	int dfu_read_medium_scsi(struct dfu_entity dfu, u64 offset, void buf, long *len)
	{
	int ret = -1;

	switch (dfu->layout) {
	case DFU_RAW_ADDR:
	ret = scsi_block_op(DFU_OP_READ, dfu, offset, buf, len);
	break;
	case DFU_FS_FAT:
	case DFU_FS_EXT4:
	ret = scsi_file_buf_read(dfu, offset, buf, len);
	break;
	default:
	printf("%s: Layout (%s) not (yet) supported!\n", __func__,
	dfu_get_layout(dfu->layout));
	}

	return ret;
	}

	void dfu_free_entity_scsi(struct dfu_entity *dfu)
	{
	if (dfu_file_buf) {
	free(dfu_file_buf);
	dfu_file_buf = NULL;
	}
	}

	/*
	* @param s Parameter string containing space-separated arguments:
	* 1st:
	* raw (raw read/write)
	* fat (files)
	* ext4 (^)
	* part (partition image)
	* 2nd and 3rd:
	* lba_start and lba_size, for raw write
	* scsi_dev and scsi_part, for filesystems and part
	*/
	int dfu_fill_entity_scsi(struct dfu_entity dfu, char devstr, char **argv, int argc)
	{
	const char *entity_type;
	ssize_t second_arg;
	ssize_t third_arg = -1;
	struct udevice *scsi;
	struct blk_desc *blk_dev;
	int ret;
	char *s;

	if (argc < 2) {
	pr_err("Need at least one argument\n");
	return -EINVAL;
	}

	dfu->data.scsi.lun = dectoul(devstr, &s);
	if (*s)
	return -EINVAL;

	entity_type = argv[0];
	/*
	* Base 0 means we'll accept (prefixed with 0x or 0) base 16, 8,
	* with default 10.
	*/
	second_arg = simple_strtol(argv[1], &s, 0);
	if (*s)
	return -EINVAL;
	if (argc >= 3) {
	third_arg = simple_strtoul(argv[2], &s, 0);
	if (*s)
	return -EINVAL;
	}

	if (scsi_scan(false)) {
	pr_err("Couldn't init scsi device.\n");
	return -ENODEV;
	}

	ret = find_scsi_device(dfu->data.scsi.lun, &scsi);
	if (ret < 0) {
	pr_err("Couldn't find scsi device no. %d.\n", dfu->data.scsi.lun);
	return -ENODEV;
	}

	blk_dev = scsi_get_blk_desc(scsi);
	if (!blk_dev) {
	pr_err("Couldn't get block device for scsi device no. %d.\n", dfu->data.scsi.lun);
	return -ENODEV;
	}

	/* if it's NOT a raw write */
	if (strcmp(entity_type, "raw")) {
	dfu->data.scsi.dev = (second_arg != -1) ? second_arg : dfu->data.scsi.lun;
	dfu->data.scsi.part = third_arg;
	}

	if (!strcmp(entity_type, "raw")) {
	dfu->layout = DFU_RAW_ADDR;
	dfu->data.scsi.lba_start = second_arg;
	if (third_arg < 0) {
	pr_err("raw requires two arguments\n");
	return -EINVAL;
	}
	dfu->data.scsi.lba_size = third_arg;
	dfu->data.scsi.lba_blk_size = blk_dev->blksz;

	/*
	* In case the size is zero (i.e. scsi raw 0x10 0),
	* assume the user intends to use whole device.
	*/
	if (third_arg == 0)
	dfu->data.scsi.lba_size = blk_dev->lba;

	} else if (!strcmp(entity_type, "part")) {
	struct disk_partition partinfo;
	int scsipart = second_arg;

	if (third_arg >= 0) {
	pr_err("part only accepts one argument\n");
	return -EINVAL;
	}

	if (part_get_info(blk_dev, scsipart, &partinfo) != 0) {
	pr_err("Couldn't find part #%d on scsi device #%d\n", scsipart,
	dfu->data.scsi.lun);
	return -ENODEV;
	}

	dfu->layout = DFU_RAW_ADDR;
	dfu->data.scsi.lba_start = partinfo.start;
	dfu->data.scsi.lba_size = partinfo.size;
	dfu->data.scsi.lba_blk_size = partinfo.blksz;
	} else if (!strcmp(entity_type, "fat")) {
	dfu->layout = DFU_FS_FAT;
	} else if (!strcmp(entity_type, "ext4")) {
	dfu->layout = DFU_FS_EXT4;
	} else if (!strcmp(entity_type, "skip")) {
	dfu->layout = DFU_SKIP;
	} else if (!strcmp(entity_type, "script")) {
	dfu->layout = DFU_SCRIPT;
	} else {
	pr_err("Memory layout (%s) not supported!\n", entity_type);
	return -ENODEV;
	}

	dfu->dev_type = DFU_DEV_SCSI;
	dfu->get_medium_size = dfu_get_medium_size_scsi;
	dfu->read_medium = dfu_read_medium_scsi;
	dfu->write_medium = dfu_write_medium_scsi;
	dfu->flush_medium = dfu_flush_medium_scsi;
	dfu->inited = 0;
	dfu->free_entity = dfu_free_entity_scsi;

	/* Check if file buffer is ready */
	if (!dfu_file_buf) {
	dfu_file_buf = memalign(CONFIG_SYS_CACHELINE_SIZE, CONFIG_SYS_DFU_MAX_FILE_SIZE);
	if (!dfu_file_buf) {
	pr_err("Could not memalign 0x%x bytes\n", CONFIG_SYS_DFU_MAX_FILE_SIZE);
	return -ENOMEM;
	}
	}

	return 0;
	}