x86: Add ifwitool for Intel Integrated Firmware Image

Some Intel SoCs from about 2016 boot using an internal microcontroller via
an 'IFWI' image. This is a special format which can hold firmware images.
In U-Boot's case it holds u-boot-tpl.bin.

Add this tool, taken from coreboot, so that we can build bootable images
on apollolake SoCs.

This tool itself has no tests. Some amount of coverage will be provided by
the binman tests that use it, so enable building the tool on sandbox.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/Makefile b/tools/Makefile
index 33e90a8..87d81a3 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -175,6 +175,9 @@
 ifdtool-objs := $(LIBFDT_OBJS) ifdtool.o
 hostprogs-$(CONFIG_X86) += ifdtool
 
+ifwitool-objs := ifwitool.o
+hostprogs-$(CONFIG_X86)$(CONFIG_SANDBOX) += ifwitool
+
 hostprogs-$(CONFIG_MX23) += mxsboot
 hostprogs-$(CONFIG_MX28) += mxsboot
 HOSTCFLAGS_mxsboot.o := -pedantic
diff --git a/tools/ifwitool.c b/tools/ifwitool.c
new file mode 100644
index 0000000..2e020a8
--- /dev/null
+++ b/tools/ifwitool.c
@@ -0,0 +1,2304 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ifwitool, CLI utility for Integrated Firmware Image (IFWI) manipulation
+ *
+ * This is taken from the Coreboot project
+ */
+
+#include <assert.h>
+#include <stdbool.h>
+#include <getopt.h>
+#include "os_support.h"
+
+#define __packed		__attribute__((packed))
+#define KiB			1024
+#define ALIGN(x, a)		__ALIGN_MASK((x), (typeof(x))(a) - 1)
+#define __ALIGN_MASK(x, mask)	(((x) + (mask)) & ~(mask))
+#define ARRAY_SIZE(x)		(sizeof(x) / sizeof((x)[0]))
+
+/*
+ * min()/max()/clamp() macros that also do
+ * strict type-checking.. See the
+ * "unnecessary" pointer comparison.
+ */
+#define min(x, y) ({				\
+	typeof(x) _min1 = (x);			\
+	typeof(y) _min2 = (y);			\
+	(void)&_min1 == &_min2);		\
+	_min1 < _min2 ? _min1 : _min2; })
+
+#define max(x, y) ({				\
+	typeof(x) _max1 = (x);			\
+	typeof(y) _max2 = (y);			\
+	(void)(&_max1 == &_max2);		\
+	_max1 > _max2 ? _max1 : _max2; })
+
+static int verbose = 1;
+
+/* Buffer and file I/O */
+struct buffer {
+	char *name;
+	char *data;
+	size_t offset;
+	size_t size;
+};
+
+#define ERROR(...) { fprintf(stderr, "E: " __VA_ARGS__); }
+#define INFO(...) { if (verbose > 0) fprintf(stderr, "INFO: " __VA_ARGS__); }
+#define DEBUG(...) { if (verbose > 1) fprintf(stderr, "DEBUG: " __VA_ARGS__); }
+
+/*
+ * BPDT is Boot Partition Descriptor Table. It is located at the start of a
+ * logical boot partition(LBP). It stores information about the critical
+ * sub-partitions present within the LBP.
+ *
+ * S-BPDT is Secondary Boot Partition Descriptor Table. It is located after the
+ * critical sub-partitions and contains information about the non-critical
+ * sub-partitions present within the LBP.
+ *
+ * Both tables are identified by BPDT_SIGNATURE stored at the start of the
+ * table.
+ */
+#define BPDT_SIGNATURE				(0x000055AA)
+
+/* Parameters passed in by caller */
+static struct param {
+	const char *file_name;
+	const char *subpart_name;
+	const char *image_name;
+	bool dir_ops;
+	const char *dentry_name;
+} param;
+
+struct bpdt_header {
+	/*
+	 * This is used to identify start of BPDT. It should always be
+	 * BPDT_SIGNATURE.
+	 */
+	uint32_t signature;
+	/* Count of BPDT entries present */
+	uint16_t descriptor_count;
+	/* Version - Currently supported = 1 */
+	uint16_t bpdt_version;
+	/* Unused - Should be 0 */
+	uint32_t xor_redundant_block;
+	/* Version of IFWI build */
+	uint32_t ifwi_version;
+	/* Version of FIT tool used to create IFWI */
+	uint64_t fit_tool_version;
+} __packed;
+#define BPDT_HEADER_SIZE			(sizeof(struct bpdt_header))
+
+struct bpdt_entry {
+	/* Type of sub-partition */
+	uint16_t type;
+	/* Attributes of sub-partition */
+	uint16_t flags;
+	/* Offset of sub-partition from beginning of LBP */
+	uint32_t offset;
+	/* Size in bytes of sub-partition */
+	uint32_t size;
+} __packed;
+#define BPDT_ENTRY_SIZE			(sizeof(struct bpdt_entry))
+
+struct bpdt {
+	struct bpdt_header h;
+	/* In practice, this could be an array of 0 to n entries */
+	struct bpdt_entry e[0];
+} __packed;
+
+static inline size_t get_bpdt_size(struct bpdt_header *h)
+{
+	return (sizeof(*h) + BPDT_ENTRY_SIZE * h->descriptor_count);
+}
+
+/* Minimum size in bytes allocated to BPDT in IFWI */
+#define BPDT_MIN_SIZE			((size_t)512)
+
+/* Header to define directory header for sub-partition */
+struct subpart_dir_header {
+	/* Should be SUBPART_DIR_MARKER */
+	uint32_t marker;
+	/* Number of directory entries in the sub-partition */
+	uint32_t num_entries;
+	/* Currenty supported - 1 */
+	uint8_t header_version;
+	/* Currenty supported - 1 */
+	uint8_t entry_version;
+	/* Length of directory header in bytes */
+	uint8_t header_length;
+	/*
+	 * 2s complement of 8-bit sum from first byte of header to last byte of
+	 * last directory entry.
+	 */
+	uint8_t checksum;
+	/* ASCII short name of sub-partition */
+	uint8_t name[4];
+} __packed;
+#define SUBPART_DIR_HEADER_SIZE			\
+					(sizeof(struct subpart_dir_header))
+#define SUBPART_DIR_MARKER				0x44504324
+#define SUBPART_DIR_HEADER_VERSION_SUPPORTED	1
+#define SUBPART_DIR_ENTRY_VERSION_SUPPORTED	1
+
+/* Structure for each directory entry for sub-partition */
+struct subpart_dir_entry {
+	/* Name of directory entry - Not guaranteed to be NULL-terminated */
+	uint8_t name[12];
+	/* Offset of entry from beginning of sub-partition */
+	uint32_t offset;
+	/* Length in bytes of sub-directory entry */
+	uint32_t length;
+	/* Must be zero */
+	uint32_t rsvd;
+} __packed;
+#define SUBPART_DIR_ENTRY_SIZE			\
+					(sizeof(struct subpart_dir_entry))
+
+struct subpart_dir {
+	struct subpart_dir_header h;
+	/* In practice, this could be an array of 0 to n entries */
+	struct subpart_dir_entry e[0];
+} __packed;
+
+static inline size_t subpart_dir_size(struct subpart_dir_header *h)
+{
+	return (sizeof(*h) + SUBPART_DIR_ENTRY_SIZE * h->num_entries);
+}
+
+struct manifest_header {
+	uint32_t header_type;
+	uint32_t header_length;
+	uint32_t header_version;
+	uint32_t flags;
+	uint32_t vendor;
+	uint32_t date;
+	uint32_t size;
+	uint32_t id;
+	uint32_t rsvd;
+	uint64_t version;
+	uint32_t svn;
+	uint64_t rsvd1;
+	uint8_t rsvd2[64];
+	uint32_t modulus_size;
+	uint32_t exponent_size;
+	uint8_t public_key[256];
+	uint32_t exponent;
+	uint8_t signature[256];
+} __packed;
+
+#define DWORD_SIZE				4
+#define MANIFEST_HDR_SIZE			(sizeof(struct manifest_header))
+#define MANIFEST_ID_MAGIC			(0x324e4d24)
+
+struct module {
+	uint8_t name[12];
+	uint8_t type;
+	uint8_t hash_alg;
+	uint16_t hash_size;
+	uint32_t metadata_size;
+	uint8_t metadata_hash[32];
+} __packed;
+
+#define MODULE_SIZE				(sizeof(struct module))
+
+struct signed_pkg_info_ext {
+	uint32_t ext_type;
+	uint32_t ext_length;
+	uint8_t name[4];
+	uint32_t vcn;
+	uint8_t bitmap[16];
+	uint32_t svn;
+	uint8_t rsvd[16];
+} __packed;
+
+#define SIGNED_PKG_INFO_EXT_TYPE		0x15
+#define SIGNED_PKG_INFO_EXT_SIZE		\
+	(sizeof(struct signed_pkg_info_ext))
+
+/*
+ * Attributes for various IFWI sub-partitions.
+ * LIES_WITHIN_BPDT_4K = Sub-Partition should lie within the same 4K block as
+ * BPDT.
+ * NON_CRITICAL_SUBPART = Sub-Partition entry should be present in S-BPDT.
+ * CONTAINS_DIR = Sub-Partition contains directory.
+ * AUTO_GENERATED = Sub-Partition is generated by the tool.
+ * MANDATORY_BPDT_ENTRY = Even if sub-partition is deleted, BPDT should contain
+ * an entry for it with size 0 and offset 0.
+ */
+enum subpart_attributes {
+	LIES_WITHIN_BPDT_4K = (1 << 0),
+	NON_CRITICAL_SUBPART = (1 << 1),
+	CONTAINS_DIR = (1 << 2),
+	AUTO_GENERATED = (1 << 3),
+	MANDATORY_BPDT_ENTRY = (1 << 4),
+};
+
+/* Type value for various IFWI sub-partitions */
+enum bpdt_entry_type {
+	SMIP_TYPE		= 0,
+	CSE_RBE_TYPE		= 1,
+	CSE_BUP_TYPE		= 2,
+	UCODE_TYPE		= 3,
+	IBB_TYPE		= 4,
+	S_BPDT_TYPE		= 5,
+	OBB_TYPE		= 6,
+	CSE_MAIN_TYPE		= 7,
+	ISH_TYPE		= 8,
+	CSE_IDLM_TYPE		= 9,
+	IFP_OVERRIDE_TYPE	= 10,
+	DEBUG_TOKENS_TYPE	= 11,
+	UFS_PHY_TYPE		= 12,
+	UFS_GPP_TYPE		= 13,
+	PMC_TYPE		= 14,
+	IUNIT_TYPE		= 15,
+	NVM_CONFIG_TYPE	= 16,
+	UEP_TYPE		= 17,
+	UFS_RATE_B_TYPE	= 18,
+	MAX_SUBPARTS		= 19,
+};
+
+/*
+ * There are two order requirements for an IFWI image:
+ * 1. Order in which the sub-partitions lie within the BPDT entries.
+ * 2. Order in which the sub-partitions lie within the image.
+ *
+ * header_order defines #1 i.e. the order in which the sub-partitions should
+ * appear in the BPDT entries. pack_order defines #2 i.e. the order in which
+ * sub-partitions appear in the IFWI image. pack_order controls the offset and
+ * thus sub-partitions would have increasing offsets as we loop over pack_order.
+ */
+const enum bpdt_entry_type bpdt_header_order[MAX_SUBPARTS] = {
+	/* Order of the following entries is mandatory */
+	CSE_IDLM_TYPE,
+	IFP_OVERRIDE_TYPE,
+	S_BPDT_TYPE,
+	CSE_RBE_TYPE,
+	UFS_PHY_TYPE,
+	UFS_GPP_TYPE,
+	/* Order of the following entries is recommended */
+	UEP_TYPE,
+	NVM_CONFIG_TYPE,
+	UFS_RATE_B_TYPE,
+	IBB_TYPE,
+	SMIP_TYPE,
+	PMC_TYPE,
+	CSE_BUP_TYPE,
+	UCODE_TYPE,
+	DEBUG_TOKENS_TYPE,
+	IUNIT_TYPE,
+	CSE_MAIN_TYPE,
+	ISH_TYPE,
+	OBB_TYPE,
+};
+
+const enum bpdt_entry_type bpdt_pack_order[MAX_SUBPARTS] = {
+	/* Order of the following entries is mandatory */
+	UFS_GPP_TYPE,
+	UFS_PHY_TYPE,
+	IFP_OVERRIDE_TYPE,
+	UEP_TYPE,
+	NVM_CONFIG_TYPE,
+	UFS_RATE_B_TYPE,
+	/* Order of the following entries is recommended */
+	IBB_TYPE,
+	SMIP_TYPE,
+	CSE_RBE_TYPE,
+	PMC_TYPE,
+	CSE_BUP_TYPE,
+	UCODE_TYPE,
+	CSE_IDLM_TYPE,
+	DEBUG_TOKENS_TYPE,
+	S_BPDT_TYPE,
+	IUNIT_TYPE,
+	CSE_MAIN_TYPE,
+	ISH_TYPE,
+	OBB_TYPE,
+};
+
+/* Utility functions */
+enum ifwi_ret {
+	COMMAND_ERR = -1,
+	NO_ACTION_REQUIRED = 0,
+	REPACK_REQUIRED = 1,
+};
+
+struct dir_ops {
+	enum ifwi_ret (*dir_add)(int type);
+};
+
+static enum ifwi_ret ibbp_dir_add(int type);
+
+const struct subpart_info {
+	const char *name;
+	const char *readable_name;
+	uint32_t attr;
+	struct dir_ops dir_ops;
+} subparts[MAX_SUBPARTS] = {
+	/* OEM SMIP */
+	[SMIP_TYPE] = {"SMIP", "SMIP", CONTAINS_DIR, {NULL} },
+	/* CSE RBE */
+	[CSE_RBE_TYPE] = {"RBEP", "CSE_RBE", CONTAINS_DIR |
+			  MANDATORY_BPDT_ENTRY, {NULL} },
+	/* CSE BUP */
+	[CSE_BUP_TYPE] = {"FTPR", "CSE_BUP", CONTAINS_DIR |
+			  MANDATORY_BPDT_ENTRY, {NULL} },
+	/* uCode */
+	[UCODE_TYPE] = {"UCOD", "Microcode", CONTAINS_DIR, {NULL} },
+	/* IBB */
+	[IBB_TYPE] = {"IBBP", "Bootblock", CONTAINS_DIR, {ibbp_dir_add} },
+	/* S-BPDT */
+	[S_BPDT_TYPE] = {"S_BPDT", "S-BPDT", AUTO_GENERATED |
+			 MANDATORY_BPDT_ENTRY, {NULL} },
+	/* OBB */
+	[OBB_TYPE] = {"OBBP", "OEM boot block", CONTAINS_DIR |
+		      NON_CRITICAL_SUBPART, {NULL} },
+	/* CSE Main */
+	[CSE_MAIN_TYPE] = {"NFTP", "CSE_MAIN", CONTAINS_DIR |
+			   NON_CRITICAL_SUBPART, {NULL} },
+	/* ISH */
+	[ISH_TYPE] = {"ISHP", "ISH", NON_CRITICAL_SUBPART, {NULL} },
+	/* CSE IDLM */
+	[CSE_IDLM_TYPE] = {"DLMP", "CSE_IDLM", CONTAINS_DIR |
+			   MANDATORY_BPDT_ENTRY, {NULL} },
+	/* IFP Override */
+	[IFP_OVERRIDE_TYPE] = {"IFP_OVERRIDE", "IFP_OVERRIDE",
+			       LIES_WITHIN_BPDT_4K | MANDATORY_BPDT_ENTRY,
+			       {NULL} },
+	/* Debug Tokens */
+	[DEBUG_TOKENS_TYPE] = {"DEBUG_TOKENS", "Debug Tokens", 0, {NULL} },
+	/* UFS Phy Configuration */
+	[UFS_PHY_TYPE] = {"UFS_PHY", "UFS Phy", LIES_WITHIN_BPDT_4K |
+			  MANDATORY_BPDT_ENTRY, {NULL} },
+	/* UFS GPP LUN ID */
+	[UFS_GPP_TYPE] = {"UFS_GPP", "UFS GPP", LIES_WITHIN_BPDT_4K |
+			  MANDATORY_BPDT_ENTRY, {NULL} },
+	/* PMC */
+	[PMC_TYPE] = {"PMCP", "PMC firmware", CONTAINS_DIR, {NULL} },
+	/* IUNIT */
+	[IUNIT_TYPE] = {"IUNP", "IUNIT", NON_CRITICAL_SUBPART, {NULL} },
+	/* NVM Config */
+	[NVM_CONFIG_TYPE] = {"NVM_CONFIG", "NVM Config", 0, {NULL} },
+	/* UEP */
+	[UEP_TYPE] = {"UEP", "UEP", LIES_WITHIN_BPDT_4K | MANDATORY_BPDT_ENTRY,
+		      {NULL} },
+	/* UFS Rate B Config */
+	[UFS_RATE_B_TYPE] = {"UFS_RATE_B", "UFS Rate B Config", 0, {NULL} },
+};
+
+struct ifwi_image {
+	/* Data read from input file */
+	struct buffer input_buff;
+
+	/* BPDT header and entries */
+	struct buffer bpdt;
+	size_t input_ifwi_start_offset;
+	size_t input_ifwi_end_offset;
+
+	/* Subpartition content */
+	struct buffer subpart_buf[MAX_SUBPARTS];
+} ifwi_image;
+
+/* Buffer and file I/O */
+static off_t get_file_size(FILE *f)
+{
+	off_t fsize;
+
+	fseek(f, 0, SEEK_END);
+	fsize = ftell(f);
+	fseek(f, 0, SEEK_SET);
+	return fsize;
+}
+
+static inline void *buffer_get(const struct buffer *b)
+{
+	return b->data;
+}
+
+static inline size_t buffer_size(const struct buffer *b)
+{
+	return b->size;
+}
+
+static inline size_t buffer_offset(const struct buffer *b)
+{
+	return b->offset;
+}
+
+/*
+ * Shrink a buffer toward the beginning of its previous space.
+ * Afterward, buffer_delete() remains the means of cleaning it up
+ */
+static inline void buffer_set_size(struct buffer *b, size_t size)
+{
+	b->size = size;
+}
+
+/* Splice a buffer into another buffer. Note that it's up to the caller to
+ * bounds check the offset and size. The resulting buffer is backed by the same
+ * storage as the original, so although it is valid to buffer_delete() either
+ * one of them, doing so releases both simultaneously
+ */
+static void buffer_splice(struct buffer *dest, const struct buffer *src,
+			  size_t offset, size_t size)
+{
+	dest->name = src->name;
+	dest->data = src->data + offset;
+	dest->offset = src->offset + offset;
+	dest->size = size;
+}
+
+/*
+ * Shrink a buffer toward the end of its previous space.
+ * Afterward, buffer_delete() remains the means of cleaning it up
+ */
+static inline void buffer_seek(struct buffer *b, size_t size)
+{
+	b->offset += size;
+	b->size -= size;
+	b->data += size;
+}
+
+/* Returns the start of the underlying buffer, with the offset undone */
+static inline void *buffer_get_original_backing(const struct buffer *b)
+{
+	if (!b)
+		return NULL;
+	return buffer_get(b) - buffer_offset(b);
+}
+
+int buffer_create(struct buffer *buffer, size_t size, const char *name)
+{
+	buffer->name = strdup(name);
+	buffer->offset = 0;
+	buffer->size = size;
+	buffer->data = (char *)malloc(buffer->size);
+	if (!buffer->data) {
+		fprintf(stderr, "%s: Insufficient memory (0x%zx).\n", __func__,
+			size);
+	}
+
+	return !buffer->data;
+}
+
+int buffer_write_file(struct buffer *buffer, const char *filename)
+{
+	FILE *fp = fopen(filename, "wb");
+
+	if (!fp) {
+		perror(filename);
+		return -1;
+	}
+	assert(buffer && buffer->data);
+	if (fwrite(buffer->data, 1, buffer->size, fp) != buffer->size) {
+		fprintf(stderr, "incomplete write: %s\n", filename);
+		fclose(fp);
+		return -1;
+	}
+	fclose(fp);
+	return 0;
+}
+
+void buffer_delete(struct buffer *buffer)
+{
+	assert(buffer);
+	if (buffer->name) {
+		free(buffer->name);
+		buffer->name = NULL;
+	}
+	if (buffer->data) {
+		free(buffer_get_original_backing(buffer));
+		buffer->data = NULL;
+	}
+	buffer->offset = 0;
+	buffer->size = 0;
+}
+
+int buffer_from_file(struct buffer *buffer, const char *filename)
+{
+	FILE *fp = fopen(filename, "rb");
+
+	if (!fp) {
+		perror(filename);
+		return -1;
+	}
+	buffer->offset = 0;
+	off_t file_size = get_file_size(fp);
+
+	if (file_size < 0) {
+		fprintf(stderr, "could not determine size of %s\n", filename);
+		fclose(fp);
+		return -1;
+	}
+	buffer->size = file_size;
+	buffer->name = strdup(filename);
+	buffer->data = (char *)malloc(buffer->size);
+	assert(buffer->data);
+	if (fread(buffer->data, 1, buffer->size, fp) != buffer->size) {
+		fprintf(stderr, "incomplete read: %s\n", filename);
+		fclose(fp);
+		buffer_delete(buffer);
+		return -1;
+	}
+	fclose(fp);
+	return 0;
+}
+
+static void alloc_buffer(struct buffer *b, size_t s, const char *n)
+{
+	if (buffer_create(b, s, n) == 0)
+		return;
+
+	ERROR("Buffer allocation failure for %s (size = %zx).\n", n, s);
+	exit(-1);
+}
+
+/* Little-Endian functions */
+static inline uint8_t read_ble8(const void *src)
+{
+	const uint8_t *s = src;
+	return *s;
+}
+
+static inline uint8_t read_at_ble8(const void *src, size_t offset)
+{
+	const uint8_t *s = src;
+
+	s += offset;
+	return read_ble8(s);
+}
+
+static inline void write_ble8(void *dest, uint8_t val)
+{
+	*(uint8_t *)dest = val;
+}
+
+static inline void write_at_ble8(void *dest, uint8_t val, size_t offset)
+{
+	uint8_t *d = dest;
+
+	d += offset;
+	write_ble8(d, val);
+}
+
+static inline uint8_t read_at_le8(const void *src, size_t offset)
+{
+	return read_at_ble8(src, offset);
+}
+
+static inline void write_le8(void *dest, uint8_t val)
+{
+	write_ble8(dest, val);
+}
+
+static inline void write_at_le8(void *dest, uint8_t val, size_t offset)
+{
+	write_at_ble8(dest, val, offset);
+}
+
+static inline uint16_t read_le16(const void *src)
+{
+	const uint8_t *s = src;
+
+	return (((uint16_t)s[1]) << 8) | (((uint16_t)s[0]) << 0);
+}
+
+static inline uint16_t read_at_le16(const void *src, size_t offset)
+{
+	const uint8_t *s = src;
+
+	s += offset;
+	return read_le16(s);
+}
+
+static inline void write_le16(void *dest, uint16_t val)
+{
+	write_le8(dest, val >> 0);
+	write_at_le8(dest, val >> 8, sizeof(uint8_t));
+}
+
+static inline void write_at_le16(void *dest, uint16_t val, size_t offset)
+{
+	uint8_t *d = dest;
+
+	d += offset;
+	write_le16(d, val);
+}
+
+static inline uint32_t read_le32(const void *src)
+{
+	const uint8_t *s = src;
+
+	return (((uint32_t)s[3]) << 24) | (((uint32_t)s[2]) << 16) |
+		(((uint32_t)s[1]) << 8) | (((uint32_t)s[0]) << 0);
+}
+
+static inline uint32_t read_at_le32(const void *src, size_t offset)
+{
+	const uint8_t *s = src;
+
+	s += offset;
+	return read_le32(s);
+}
+
+static inline void write_le32(void *dest, uint32_t val)
+{
+	write_le16(dest, val >> 0);
+	write_at_le16(dest, val >> 16, sizeof(uint16_t));
+}
+
+static inline void write_at_le32(void *dest, uint32_t val, size_t offset)
+{
+	uint8_t *d = dest;
+
+	d += offset;
+	write_le32(d, val);
+}
+
+static inline uint64_t read_le64(const void *src)
+{
+	uint64_t val;
+
+	val = read_at_le32(src, sizeof(uint32_t));
+	val <<= 32;
+	val |= read_le32(src);
+	return val;
+}
+
+static inline uint64_t read_at_le64(const void *src, size_t offset)
+{
+	const uint8_t *s = src;
+
+	s += offset;
+	return read_le64(s);
+}
+
+static inline void write_le64(void *dest, uint64_t val)
+{
+	write_le32(dest, val >> 0);
+	write_at_le32(dest, val >> 32, sizeof(uint32_t));
+}
+
+static inline void write_at_le64(void *dest, uint64_t val, size_t offset)
+{
+	uint8_t *d = dest;
+
+	d += offset;
+	write_le64(d, val);
+}
+
+/*
+ * Read header/entry members in little-endian format.
+ * Returns the offset upto which the read was performed.
+ */
+static size_t read_member(void *src, size_t offset, size_t size_bytes,
+			  void *dst)
+{
+	switch (size_bytes) {
+	case 1:
+		*(uint8_t *)dst = read_at_le8(src, offset);
+		break;
+	case 2:
+		*(uint16_t *)dst = read_at_le16(src, offset);
+		break;
+	case 4:
+		*(uint32_t *)dst = read_at_le32(src, offset);
+		break;
+	case 8:
+		*(uint64_t *)dst = read_at_le64(src, offset);
+		break;
+	default:
+		ERROR("Read size not supported %zd\n", size_bytes);
+		exit(-1);
+	}
+
+	return (offset + size_bytes);
+}
+
+/*
+ * Convert to little endian format.
+ * Returns the offset upto which the fixup was performed.
+ */
+static size_t fix_member(void *data, size_t offset, size_t size_bytes)
+{
+	uint8_t *src = (uint8_t *)data + offset;
+
+	switch (size_bytes) {
+	case 1:
+		write_at_le8(data, *(uint8_t *)src, offset);
+		break;
+	case 2:
+		write_at_le16(data, *(uint16_t *)src, offset);
+		break;
+	case 4:
+		write_at_le32(data, *(uint32_t *)src, offset);
+		break;
+	case 8:
+		write_at_le64(data, *(uint64_t *)src, offset);
+		break;
+	default:
+		ERROR("Write size not supported %zd\n", size_bytes);
+		exit(-1);
+	}
+	return (offset + size_bytes);
+}
+
+static void print_subpart_dir(struct subpart_dir *s)
+{
+	if (verbose == 0)
+		return;
+
+	size_t i;
+
+	printf("%-25s 0x%-23.8x\n", "Marker", s->h.marker);
+	printf("%-25s %-25d\n", "Num entries", s->h.num_entries);
+	printf("%-25s %-25d\n", "Header Version", s->h.header_version);
+	printf("%-25s %-25d\n", "Entry Version", s->h.entry_version);
+	printf("%-25s 0x%-23x\n", "Header Length", s->h.header_length);
+	printf("%-25s 0x%-23x\n", "Checksum", s->h.checksum);
+	printf("%-25s ", "Name");
+	for (i = 0; i < sizeof(s->h.name); i++)
+		printf("%c", s->h.name[i]);
+
+	printf("\n");
+
+	printf("%-25s%-25s%-25s%-25s%-25s\n", "Entry #", "Name", "Offset",
+	       "Length", "Rsvd");
+
+	printf("=========================================================================================================================\n");
+
+	for (i = 0; i < s->h.num_entries; i++) {
+		printf("%-25zd%-25.12s0x%-23x0x%-23x0x%-23x\n", i + 1,
+		       s->e[i].name, s->e[i].offset, s->e[i].length,
+		       s->e[i].rsvd);
+	}
+
+	printf("=========================================================================================================================\n");
+}
+
+static void bpdt_print_header(struct bpdt_header *h, const char *name)
+{
+	if (verbose == 0)
+		return;
+
+	printf("%-25s %-25s\n", "Header", name);
+	printf("%-25s 0x%-23.8x\n", "Signature", h->signature);
+	printf("%-25s %-25d\n", "Descriptor count", h->descriptor_count);
+	printf("%-25s %-25d\n", "BPDT Version", h->bpdt_version);
+	printf("%-25s 0x%-23x\n", "XOR checksum", h->xor_redundant_block);
+	printf("%-25s 0x%-23x\n", "IFWI Version", h->ifwi_version);
+	printf("%-25s 0x%-23llx\n", "FIT Tool Version",
+	       (long long)h->fit_tool_version);
+}
+
+static void bpdt_print_entries(struct bpdt_entry *e, size_t count,
+			       const char *name)
+{
+	size_t i;
+
+	if (verbose == 0)
+		return;
+
+	printf("%s entries\n", name);
+
+	printf("%-25s%-25s%-25s%-25s%-25s%-25s%-25s%-25s\n", "Entry #",
+	       "Sub-Partition", "Name", "Type", "Flags", "Offset", "Size",
+	       "File Offset");
+
+	printf("=========================================================================================================================================================================================================\n");
+
+	for (i = 0; i < count; i++) {
+		printf("%-25zd%-25s%-25s%-25d0x%-23.08x0x%-23x0x%-23x0x%-23zx\n",
+		       i + 1, subparts[e[i].type].name,
+		       subparts[e[i].type].readable_name, e[i].type, e[i].flags,
+		       e[i].offset, e[i].size,
+		       e[i].offset + ifwi_image.input_ifwi_start_offset);
+	}
+
+	printf("=========================================================================================================================================================================================================\n");
+}
+
+static void bpdt_validate_header(struct bpdt_header *h, const char *name)
+{
+	assert(h->signature == BPDT_SIGNATURE);
+
+	if (h->bpdt_version != 1) {
+		ERROR("Invalid header : %s\n", name);
+		exit(-1);
+	}
+
+	DEBUG("Validated header : %s\n", name);
+}
+
+static void bpdt_read_header(void *data, struct bpdt_header *h,
+			     const char *name)
+{
+	size_t offset = 0;
+
+	offset = read_member(data, offset, sizeof(h->signature), &h->signature);
+	offset = read_member(data, offset, sizeof(h->descriptor_count),
+			     &h->descriptor_count);
+	offset = read_member(data, offset, sizeof(h->bpdt_version),
+			     &h->bpdt_version);
+	offset = read_member(data, offset, sizeof(h->xor_redundant_block),
+			     &h->xor_redundant_block);
+	offset = read_member(data, offset, sizeof(h->ifwi_version),
+			     &h->ifwi_version);
+	read_member(data, offset, sizeof(h->fit_tool_version),
+		    &h->fit_tool_version);
+
+	bpdt_validate_header(h, name);
+	bpdt_print_header(h, name);
+}
+
+static void bpdt_read_entries(void *data, struct bpdt *bpdt, const char *name)
+{
+	size_t i, offset = 0;
+	struct bpdt_entry *e = &bpdt->e[0];
+	size_t count = bpdt->h.descriptor_count;
+
+	for (i = 0; i < count; i++) {
+		offset = read_member(data, offset, sizeof(e[i].type),
+				     &e[i].type);
+		offset = read_member(data, offset, sizeof(e[i].flags),
+				     &e[i].flags);
+		offset = read_member(data, offset, sizeof(e[i].offset),
+				     &e[i].offset);
+		offset = read_member(data, offset, sizeof(e[i].size),
+				     &e[i].size);
+	}
+
+	bpdt_print_entries(e, count, name);
+}
+
+/*
+ * Given type of sub-partition, identify BPDT entry for it.
+ * Sub-Partition could lie either within BPDT or S-BPDT.
+ */
+static struct bpdt_entry *__find_entry_by_type(struct bpdt_entry *e,
+					       size_t count, int type)
+{
+	size_t i;
+
+	for (i = 0; i < count; i++) {
+		if (e[i].type == type)
+			break;
+	}
+
+	if (i == count)
+		return NULL;
+
+	return &e[i];
+}
+
+static struct bpdt_entry *find_entry_by_type(int type)
+{
+	struct bpdt *b = buffer_get(&ifwi_image.bpdt);
+
+	if (!b)
+		return NULL;
+
+	struct bpdt_entry *curr = __find_entry_by_type(&b->e[0],
+						       b->h.descriptor_count,
+						       type);
+
+	if (curr)
+		return curr;
+
+	b = buffer_get(&ifwi_image.subpart_buf[S_BPDT_TYPE]);
+	if (!b)
+		return NULL;
+
+	return __find_entry_by_type(&b->e[0], b->h.descriptor_count, type);
+}
+
+/*
+ * Find sub-partition type given its name. If the name does not exist, returns
+ * -1.
+ */
+static int find_type_by_name(const char *name)
+{
+	int i;
+
+	for (i = 0; i < MAX_SUBPARTS; i++) {
+		if ((strlen(subparts[i].name) == strlen(name)) &&
+		    (!strcmp(subparts[i].name, name)))
+			break;
+	}
+
+	if (i == MAX_SUBPARTS) {
+		ERROR("Invalid sub-partition name %s.\n", name);
+		return -1;
+	}
+
+	return i;
+}
+
+/*
+ * Read the content of a sub-partition from input file and store it in
+ * ifwi_image.subpart_buf[SUB-PARTITION_TYPE].
+ *
+ * Returns the maximum offset occupied by the sub-partitions.
+ */
+static size_t read_subpart_buf(void *data, size_t size, struct bpdt_entry *e,
+			       size_t count)
+{
+	size_t i, type;
+	struct buffer *buf;
+	size_t max_offset = 0;
+
+	for (i = 0; i < count; i++) {
+		type = e[i].type;
+
+		if (type >= MAX_SUBPARTS) {
+			ERROR("Invalid sub-partition type %zd.\n", type);
+			exit(-1);
+		}
+
+		if (buffer_size(&ifwi_image.subpart_buf[type])) {
+			ERROR("Multiple sub-partitions of type %zd(%s).\n",
+			      type, subparts[type].name);
+			exit(-1);
+		}
+
+		if (e[i].size == 0) {
+			INFO("Dummy sub-partition %zd(%s). Skipping.\n", type,
+			     subparts[type].name);
+			continue;
+		}
+
+		assert((e[i].offset + e[i].size) <= size);
+
+		/*
+		 * Sub-partitions in IFWI image are not in the same order as
+		 * in BPDT entries. BPDT entires are in header_order whereas
+		 * sub-partition offsets in the image are in pack_order.
+		 */
+		if ((e[i].offset + e[i].size) > max_offset)
+			max_offset = e[i].offset + e[i].size;
+
+		/*
+		 * S-BPDT sub-partition contains information about all the
+		 * non-critical sub-partitions. Thus, size of S-BPDT
+		 * sub-partition equals size of S-BPDT plus size of all the
+		 * non-critical sub-partitions. Thus, reading whole of S-BPDT
+		 * here would be redundant as the non-critical partitions are
+		 * read and allocated buffers separately. Also, S-BPDT requires
+		 * special handling for reading header and entries.
+		 */
+		if (type == S_BPDT_TYPE)
+			continue;
+
+		buf = &ifwi_image.subpart_buf[type];
+
+		alloc_buffer(buf, e[i].size, subparts[type].name);
+		memcpy(buffer_get(buf), (uint8_t *)data + e[i].offset,
+		       e[i].size);
+	}
+
+	assert(max_offset);
+	return max_offset;
+}
+
+/*
+ * Allocate buffer for bpdt header, entries and all sub-partition content.
+ * Returns offset in data where BPDT ends.
+ */
+static size_t alloc_bpdt_buffer(void *data, size_t size, size_t offset,
+				struct buffer *b, const char *name)
+{
+	struct bpdt_header bpdt_header;
+
+	assert((offset + BPDT_HEADER_SIZE) < size);
+	bpdt_read_header((uint8_t *)data + offset, &bpdt_header, name);
+
+	/* Buffer to read BPDT header and entries */
+	alloc_buffer(b, get_bpdt_size(&bpdt_header), name);
+
+	struct bpdt *bpdt = buffer_get(b);
+
+	memcpy(&bpdt->h, &bpdt_header, BPDT_HEADER_SIZE);
+
+	/*
+	 * If no entries are present, maximum offset occupied is (offset +
+	 * BPDT_HEADER_SIZE).
+	 */
+	if (bpdt->h.descriptor_count == 0)
+		return (offset + BPDT_HEADER_SIZE);
+
+	/* Read all entries */
+	assert((offset + get_bpdt_size(&bpdt->h)) < size);
+	bpdt_read_entries((uint8_t *)data + offset + BPDT_HEADER_SIZE, bpdt,
+			  name);
+
+	/* Read all sub-partition content in subpart_buf */
+	return read_subpart_buf(data, size, &bpdt->e[0],
+				bpdt->h.descriptor_count);
+}
+
+static void parse_sbpdt(void *data, size_t size)
+{
+	struct bpdt_entry *s;
+
+	s  = find_entry_by_type(S_BPDT_TYPE);
+	if (!s)
+		return;
+
+	assert(size > s->offset);
+
+	alloc_bpdt_buffer(data, size, s->offset,
+			  &ifwi_image.subpart_buf[S_BPDT_TYPE],
+			  "S-BPDT");
+}
+
+static uint8_t calc_checksum(struct subpart_dir *s)
+{
+	size_t size = subpart_dir_size(&s->h);
+	uint8_t *data = (uint8_t *)s;
+	uint8_t checksum = 0;
+	size_t i;
+	uint8_t old_checksum = s->h.checksum;
+
+	s->h.checksum = 0;
+
+	for (i = 0; i < size; i++)
+		checksum += data[i];
+
+	s->h.checksum = old_checksum;
+
+	/* 2s complement */
+	return -checksum;
+}
+
+static void validate_subpart_dir(struct subpart_dir *s, const char *name,
+				 bool checksum_check)
+{
+	if (s->h.marker != SUBPART_DIR_MARKER ||
+	    s->h.header_version != SUBPART_DIR_HEADER_VERSION_SUPPORTED ||
+	    s->h.entry_version != SUBPART_DIR_ENTRY_VERSION_SUPPORTED ||
+	    s->h.header_length != SUBPART_DIR_HEADER_SIZE) {
+		ERROR("Invalid subpart_dir for %s.\n", name);
+		exit(-1);
+	}
+
+	if (!checksum_check)
+		return;
+
+	uint8_t checksum = calc_checksum(s);
+
+	if (checksum != s->h.checksum)
+		ERROR("Invalid checksum for %s (Expected=0x%x, Actual=0x%x).\n",
+		      name, checksum, s->h.checksum);
+}
+
+static void validate_subpart_dir_without_checksum(struct subpart_dir *s,
+						  const char *name)
+{
+	validate_subpart_dir(s, name, 0);
+}
+
+static void validate_subpart_dir_with_checksum(struct subpart_dir *s,
+					       const char *name)
+{
+	validate_subpart_dir(s, name, 1);
+}
+
+static void parse_subpart_dir(struct buffer *subpart_dir_buf,
+			      struct buffer *input_buf, const char *name)
+{
+	struct subpart_dir_header hdr;
+	size_t offset = 0;
+	uint8_t *data = buffer_get(input_buf);
+	size_t size = buffer_size(input_buf);
+
+	/* Read Subpart_Dir header */
+	assert(size >= SUBPART_DIR_HEADER_SIZE);
+	offset = read_member(data, offset, sizeof(hdr.marker), &hdr.marker);
+	offset = read_member(data, offset, sizeof(hdr.num_entries),
+			     &hdr.num_entries);
+	offset = read_member(data, offset, sizeof(hdr.header_version),
+			     &hdr.header_version);
+	offset = read_member(data, offset, sizeof(hdr.entry_version),
+			     &hdr.entry_version);
+	offset = read_member(data, offset, sizeof(hdr.header_length),
+			     &hdr.header_length);
+	offset = read_member(data, offset, sizeof(hdr.checksum), &hdr.checksum);
+	memcpy(hdr.name, data + offset, sizeof(hdr.name));
+	offset += sizeof(hdr.name);
+
+	validate_subpart_dir_without_checksum((struct subpart_dir *)&hdr, name);
+
+	assert(size > subpart_dir_size(&hdr));
+	alloc_buffer(subpart_dir_buf, subpart_dir_size(&hdr), "Subpart Dir");
+	memcpy(buffer_get(subpart_dir_buf), &hdr, SUBPART_DIR_HEADER_SIZE);
+
+	/* Read Subpart Dir entries */
+	struct subpart_dir *subpart_dir = buffer_get(subpart_dir_buf);
+	struct subpart_dir_entry *e = &subpart_dir->e[0];
+	uint32_t i;
+
+	for (i = 0; i < hdr.num_entries; i++) {
+		memcpy(e[i].name, data + offset, sizeof(e[i].name));
+		offset += sizeof(e[i].name);
+		offset = read_member(data, offset, sizeof(e[i].offset),
+				     &e[i].offset);
+		offset = read_member(data, offset, sizeof(e[i].length),
+				     &e[i].length);
+		offset = read_member(data, offset, sizeof(e[i].rsvd),
+				     &e[i].rsvd);
+	}
+
+	validate_subpart_dir_with_checksum(subpart_dir, name);
+
+	print_subpart_dir(subpart_dir);
+}
+
+/* Parse input image file to identify different sub-partitions */
+static int ifwi_parse(void)
+{
+	struct buffer *buff = &ifwi_image.input_buff;
+	const char *image_name = param.image_name;
+
+	DEBUG("Parsing IFWI image...\n");
+
+	/* Read input file */
+	if (buffer_from_file(buff, image_name)) {
+		ERROR("Failed to read input file %s.\n", image_name);
+		return -1;
+	}
+
+	INFO("Buffer %p size 0x%zx\n", buff->data, buff->size);
+
+	/* Look for BPDT signature at 4K intervals */
+	size_t offset = 0;
+	void *data = buffer_get(buff);
+
+	while (offset < buffer_size(buff)) {
+		if (read_at_le32(data, offset) == BPDT_SIGNATURE)
+			break;
+		offset += 4 * KiB;
+	}
+
+	if (offset >= buffer_size(buff)) {
+		ERROR("Image does not contain BPDT!!\n");
+		return -1;
+	}
+
+	ifwi_image.input_ifwi_start_offset = offset;
+	INFO("BPDT starts at offset 0x%zx.\n", offset);
+
+	data = (uint8_t *)data + offset;
+	size_t ifwi_size = buffer_size(buff) - offset;
+
+	/* Read BPDT and sub-partitions */
+	uintptr_t end_offset;
+
+	end_offset = ifwi_image.input_ifwi_start_offset +
+		alloc_bpdt_buffer(data, ifwi_size, 0, &ifwi_image.bpdt, "BPDT");
+
+	/* Parse S-BPDT, if any */
+	parse_sbpdt(data, ifwi_size);
+
+	/*
+	 * Store end offset of IFWI. Required for copying any trailing non-IFWI
+	 * part of the image.
+	 * ASSUMPTION: IFWI image always ends on a 4K boundary.
+	 */
+	ifwi_image.input_ifwi_end_offset = ALIGN(end_offset, 4 * KiB);
+	DEBUG("Parsing done.\n");
+
+	return 0;
+}
+
+/*
+ * This function is used by repack to count the number of BPDT and S-BPDT
+ * entries that are present. It frees the current buffers used by the entries
+ * and allocates fresh buffers that can be used for repacking. Returns BPDT
+ * entries which are empty and need to be filled in.
+ */
+static void __bpdt_reset(struct buffer *b, size_t count, size_t size)
+{
+	size_t bpdt_size = BPDT_HEADER_SIZE + count * BPDT_ENTRY_SIZE;
+
+	assert(size >= bpdt_size);
+
+	/*
+	 * If buffer does not have the required size, allocate a fresh buffer.
+	 */
+	if (buffer_size(b) != size) {
+		struct buffer temp;
+
+		alloc_buffer(&temp, size, b->name);
+		memcpy(buffer_get(&temp), buffer_get(b), buffer_size(b));
+		buffer_delete(b);
+		*b = temp;
+	}
+
+	struct bpdt *bpdt = buffer_get(b);
+	uint8_t *ptr = (uint8_t *)&bpdt->e[0];
+	size_t entries_size = BPDT_ENTRY_SIZE * count;
+
+	/* Zero out BPDT entries */
+	memset(ptr, 0, entries_size);
+	/* Fill any pad-space with FF */
+	memset(ptr + entries_size, 0xFF, size - bpdt_size);
+
+	bpdt->h.descriptor_count = count;
+}
+
+static void bpdt_reset(void)
+{
+	size_t i;
+	size_t bpdt_count = 0, sbpdt_count = 0, dummy_bpdt_count = 0;
+
+	/* Count number of BPDT and S-BPDT entries */
+	for (i = 0; i < MAX_SUBPARTS; i++) {
+		if (buffer_size(&ifwi_image.subpart_buf[i]) == 0) {
+			if (subparts[i].attr & MANDATORY_BPDT_ENTRY) {
+				bpdt_count++;
+				dummy_bpdt_count++;
+			}
+			continue;
+		}
+
+		if (subparts[i].attr & NON_CRITICAL_SUBPART)
+			sbpdt_count++;
+		else
+			bpdt_count++;
+	}
+
+	DEBUG("Count: BPDT = %zd, Dummy BPDT = %zd, S-BPDT = %zd\n", bpdt_count,
+	      dummy_bpdt_count, sbpdt_count);
+
+	/* Update BPDT if required */
+	size_t bpdt_size = max(BPDT_MIN_SIZE,
+			       BPDT_HEADER_SIZE + bpdt_count * BPDT_ENTRY_SIZE);
+	__bpdt_reset(&ifwi_image.bpdt, bpdt_count, bpdt_size);
+
+	/* Update S-BPDT if required */
+	bpdt_size = ALIGN(BPDT_HEADER_SIZE + sbpdt_count * BPDT_ENTRY_SIZE,
+			  4 * KiB);
+	__bpdt_reset(&ifwi_image.subpart_buf[S_BPDT_TYPE], sbpdt_count,
+		     bpdt_size);
+}
+
+/* Initialize BPDT entries in header order */
+static void bpdt_entries_init_header_order(void)
+{
+	int i, type;
+	size_t size;
+
+	struct bpdt *bpdt, *sbpdt, *curr;
+	size_t bpdt_curr = 0, sbpdt_curr = 0, *count_ptr;
+
+	bpdt = buffer_get(&ifwi_image.bpdt);
+	sbpdt = buffer_get(&ifwi_image.subpart_buf[S_BPDT_TYPE]);
+
+	for (i = 0; i < MAX_SUBPARTS; i++) {
+		type = bpdt_header_order[i];
+		size = buffer_size(&ifwi_image.subpart_buf[type]);
+
+		if (size == 0 && !(subparts[type].attr & MANDATORY_BPDT_ENTRY))
+			continue;
+
+		if (subparts[type].attr & NON_CRITICAL_SUBPART) {
+			curr = sbpdt;
+			count_ptr = &sbpdt_curr;
+		} else {
+			curr = bpdt;
+			count_ptr = &bpdt_curr;
+		}
+
+		assert(*count_ptr < curr->h.descriptor_count);
+		curr->e[*count_ptr].type = type;
+		curr->e[*count_ptr].flags = 0;
+		curr->e[*count_ptr].offset = 0;
+		curr->e[*count_ptr].size = size;
+
+		(*count_ptr)++;
+	}
+}
+
+static void pad_buffer(struct buffer *b, size_t size)
+{
+	size_t buff_size = buffer_size(b);
+
+	assert(buff_size <= size);
+
+	if (buff_size == size)
+		return;
+
+	struct buffer temp;
+
+	alloc_buffer(&temp, size, b->name);
+	uint8_t *data = buffer_get(&temp);
+
+	memcpy(data, buffer_get(b), buff_size);
+	memset(data + buff_size, 0xFF, size - buff_size);
+
+	*b = temp;
+}
+
+/* Initialize offsets of entries using pack order */
+static void bpdt_entries_init_pack_order(void)
+{
+	int i, type;
+	struct bpdt_entry *curr;
+	size_t curr_offset, curr_end;
+
+	curr_offset = max(BPDT_MIN_SIZE, buffer_size(&ifwi_image.bpdt));
+
+	/*
+	 * There are two types of sub-partitions that need to be handled here:
+	 *   1. Sub-partitions that lie within the same 4K as BPDT
+	 *   2. Sub-partitions that lie outside the 4K of BPDT
+	 *
+	 * For sub-partitions of type # 1, there is no requirement on the start
+	 * or end of the sub-partition. They need to be packed in without any
+	 * holes left in between. If there is any empty space left after the end
+	 * of the last sub-partition in 4K of BPDT, then that space needs to be
+	 * padded with FF bytes, but the size of the last sub-partition remains
+	 * unchanged.
+	 *
+	 * For sub-partitions of type # 2, both the start and end should be a
+	 * multiple of 4K. If not, then it needs to be padded with FF bytes and
+	 * size adjusted such that the sub-partition ends on 4K boundary.
+	 */
+
+	/* #1 Sub-partitions that lie within same 4K as BPDT */
+	struct buffer *last_bpdt_buff = &ifwi_image.bpdt;
+
+	for (i = 0; i < MAX_SUBPARTS; i++) {
+		type = bpdt_pack_order[i];
+		curr = find_entry_by_type(type);
+
+		if (!curr || curr->size == 0)
+			continue;
+
+		if (!(subparts[type].attr & LIES_WITHIN_BPDT_4K))
+			continue;
+
+		curr->offset = curr_offset;
+		curr_offset = curr->offset + curr->size;
+		last_bpdt_buff = &ifwi_image.subpart_buf[type];
+		DEBUG("type=%d, curr_offset=0x%zx, curr->offset=0x%x, curr->size=0x%x, buff_size=0x%zx\n",
+		      type, curr_offset, curr->offset, curr->size,
+		      buffer_size(&ifwi_image.subpart_buf[type]));
+	}
+
+	/* Pad ff bytes if there is any empty space left in BPDT 4K */
+	curr_end = ALIGN(curr_offset, 4 * KiB);
+	pad_buffer(last_bpdt_buff,
+		   buffer_size(last_bpdt_buff) + (curr_end - curr_offset));
+	curr_offset = curr_end;
+
+	/* #2 Sub-partitions that lie outside of BPDT 4K */
+	for (i = 0; i < MAX_SUBPARTS; i++) {
+		type = bpdt_pack_order[i];
+		curr = find_entry_by_type(type);
+
+		if (!curr || curr->size == 0)
+			continue;
+
+		if (subparts[type].attr & LIES_WITHIN_BPDT_4K)
+			continue;
+
+		assert(curr_offset == ALIGN(curr_offset, 4 * KiB));
+		curr->offset = curr_offset;
+		curr_end = ALIGN(curr->offset + curr->size, 4 * KiB);
+		curr->size = curr_end - curr->offset;
+
+		pad_buffer(&ifwi_image.subpart_buf[type], curr->size);
+
+		curr_offset = curr_end;
+		DEBUG("type=%d, curr_offset=0x%zx, curr->offset=0x%x, curr->size=0x%x, buff_size=0x%zx\n",
+		      type, curr_offset, curr->offset, curr->size,
+		      buffer_size(&ifwi_image.subpart_buf[type]));
+	}
+
+	/*
+	 * Update size of S-BPDT to include size of all non-critical
+	 * sub-partitions.
+	 *
+	 * Assumption: S-BPDT always lies at the end of IFWI image.
+	 */
+	curr = find_entry_by_type(S_BPDT_TYPE);
+	assert(curr);
+
+	assert(curr_offset == ALIGN(curr_offset, 4 * KiB));
+	curr->size = curr_offset - curr->offset;
+}
+
+/* Convert all members of BPDT to little-endian format */
+static void bpdt_fixup_write_buffer(struct buffer *buf)
+{
+	struct bpdt *s = buffer_get(buf);
+
+	struct bpdt_header *h = &s->h;
+	struct bpdt_entry *e = &s->e[0];
+
+	size_t count = h->descriptor_count;
+
+	size_t offset = 0;
+
+	offset = fix_member(&h->signature, offset, sizeof(h->signature));
+	offset = fix_member(&h->descriptor_count, offset,
+			    sizeof(h->descriptor_count));
+	offset = fix_member(&h->bpdt_version, offset, sizeof(h->bpdt_version));
+	offset = fix_member(&h->xor_redundant_block, offset,
+			    sizeof(h->xor_redundant_block));
+	offset = fix_member(&h->ifwi_version, offset, sizeof(h->ifwi_version));
+	offset = fix_member(&h->fit_tool_version, offset,
+			    sizeof(h->fit_tool_version));
+
+	uint32_t i;
+
+	for (i = 0; i < count; i++) {
+		offset = fix_member(&e[i].type, offset, sizeof(e[i].type));
+		offset = fix_member(&e[i].flags, offset, sizeof(e[i].flags));
+		offset = fix_member(&e[i].offset, offset, sizeof(e[i].offset));
+		offset = fix_member(&e[i].size, offset, sizeof(e[i].size));
+	}
+}
+
+/* Write BPDT to output buffer after fixup */
+static void bpdt_write(struct buffer *dst, size_t offset, struct buffer *src)
+{
+	bpdt_fixup_write_buffer(src);
+	memcpy(buffer_get(dst) + offset, buffer_get(src), buffer_size(src));
+}
+
+/*
+ * Follows these steps to re-create image:
+ * 1. Write any non-IFWI prefix.
+ * 2. Write out BPDT header and entries.
+ * 3. Write sub-partition buffers to respective offsets.
+ * 4. Write any non-IFWI suffix.
+ *
+ * While performing the above steps, make sure that any empty holes are filled
+ * with FF.
+ */
+static void ifwi_write(const char *image_name)
+{
+	struct bpdt_entry *s = find_entry_by_type(S_BPDT_TYPE);
+
+	assert(s);
+
+	size_t ifwi_start, ifwi_end, file_end;
+
+	ifwi_start = ifwi_image.input_ifwi_start_offset;
+	ifwi_end = ifwi_start + ALIGN(s->offset + s->size, 4 * KiB);
+	file_end = ifwi_end + (buffer_size(&ifwi_image.input_buff) -
+			       ifwi_image.input_ifwi_end_offset);
+
+	struct buffer b;
+
+	alloc_buffer(&b, file_end, "Final-IFWI");
+
+	uint8_t *input_data = buffer_get(&ifwi_image.input_buff);
+	uint8_t *output_data = buffer_get(&b);
+
+	DEBUG("ifwi_start:0x%zx, ifwi_end:0x%zx, file_end:0x%zx\n", ifwi_start,
+	      ifwi_end, file_end);
+
+	/* Copy non-IFWI prefix, if any */
+	memcpy(output_data, input_data, ifwi_start);
+
+	DEBUG("Copied non-IFWI prefix (offset=0x0, size=0x%zx).\n", ifwi_start);
+
+	struct buffer ifwi;
+
+	buffer_splice(&ifwi, &b, ifwi_start, ifwi_end - ifwi_start);
+	uint8_t *ifwi_data = buffer_get(&ifwi);
+
+	/* Copy sub-partitions using pack_order */
+	struct bpdt_entry *curr;
+	struct buffer *subpart_buf;
+	int i, type;
+
+	for (i = 0; i < MAX_SUBPARTS; i++) {
+		type = bpdt_pack_order[i];
+
+		if (type == S_BPDT_TYPE)
+			continue;
+
+		curr = find_entry_by_type(type);
+
+		if (!curr || !curr->size)
+			continue;
+
+		subpart_buf = &ifwi_image.subpart_buf[type];
+
+		DEBUG("curr->offset=0x%x, curr->size=0x%x, type=%d, write_size=0x%zx\n",
+		      curr->offset, curr->size, type, buffer_size(subpart_buf));
+
+		assert((curr->offset + buffer_size(subpart_buf)) <=
+		       buffer_size(&ifwi));
+
+		memcpy(ifwi_data + curr->offset, buffer_get(subpart_buf),
+		       buffer_size(subpart_buf));
+	}
+
+	/* Copy non-IFWI suffix, if any */
+	if (ifwi_end != file_end) {
+		memcpy(output_data + ifwi_end,
+		       input_data + ifwi_image.input_ifwi_end_offset,
+		       file_end - ifwi_end);
+		DEBUG("Copied non-IFWI suffix (offset=0x%zx,size=0x%zx).\n",
+		      ifwi_end, file_end - ifwi_end);
+	}
+
+	/*
+	 * Convert BPDT to little-endian format and write it to output buffer.
+	 * S-BPDT is written first and then BPDT.
+	 */
+	bpdt_write(&ifwi, s->offset, &ifwi_image.subpart_buf[S_BPDT_TYPE]);
+	bpdt_write(&ifwi, 0, &ifwi_image.bpdt);
+
+	if (buffer_write_file(&b, image_name)) {
+		ERROR("File write error\n");
+		exit(-1);
+	}
+
+	buffer_delete(&b);
+	printf("Image written successfully to %s.\n", image_name);
+}
+
+/*
+ * Calculate size and offset of each sub-partition again since it might have
+ * changed because of add/delete operation. Also, re-create BPDT and S-BPDT
+ * entries and write back the new IFWI image to file.
+ */
+static void ifwi_repack(void)
+{
+	bpdt_reset();
+	bpdt_entries_init_header_order();
+	bpdt_entries_init_pack_order();
+
+	struct bpdt *b = buffer_get(&ifwi_image.bpdt);
+
+	bpdt_print_entries(&b->e[0], b->h.descriptor_count, "BPDT");
+
+	b = buffer_get(&ifwi_image.subpart_buf[S_BPDT_TYPE]);
+	bpdt_print_entries(&b->e[0], b->h.descriptor_count, "S-BPDT");
+
+	DEBUG("Repack done.. writing image.\n");
+	ifwi_write(param.image_name);
+}
+
+static void init_subpart_dir_header(struct subpart_dir_header *hdr,
+				    size_t count, const char *name)
+{
+	memset(hdr, 0, sizeof(*hdr));
+
+	hdr->marker = SUBPART_DIR_MARKER;
+	hdr->num_entries = count;
+	hdr->header_version = SUBPART_DIR_HEADER_VERSION_SUPPORTED;
+	hdr->entry_version = SUBPART_DIR_ENTRY_VERSION_SUPPORTED;
+	hdr->header_length = SUBPART_DIR_HEADER_SIZE;
+	memcpy(hdr->name, name, sizeof(hdr->name));
+}
+
+static size_t init_subpart_dir_entry(struct subpart_dir_entry *e,
+				     struct buffer *b, size_t offset)
+{
+	memset(e, 0, sizeof(*e));
+
+	assert(strlen(b->name) <= sizeof(e->name));
+	strncpy((char *)e->name, (char *)b->name, sizeof(e->name));
+	e->offset = offset;
+	e->length = buffer_size(b);
+
+	return (offset + buffer_size(b));
+}
+
+static void init_manifest_header(struct manifest_header *hdr, size_t size)
+{
+	memset(hdr, 0, sizeof(*hdr));
+
+	hdr->header_type = 0x4;
+	assert((MANIFEST_HDR_SIZE % DWORD_SIZE) == 0);
+	hdr->header_length = MANIFEST_HDR_SIZE / DWORD_SIZE;
+	hdr->header_version = 0x10000;
+	hdr->vendor = 0x8086;
+
+	struct tm *local_time;
+	time_t curr_time;
+	char buffer[11];
+
+	curr_time = time(NULL);
+	local_time = localtime(&curr_time);
+	strftime(buffer, sizeof(buffer), "0x%Y%m%d", local_time);
+	hdr->date = strtoul(buffer, NULL, 16);
+
+	assert((size % DWORD_SIZE) == 0);
+	hdr->size = size / DWORD_SIZE;
+	hdr->id = MANIFEST_ID_MAGIC;
+}
+
+static void init_signed_pkg_info_ext(struct signed_pkg_info_ext *ext,
+				     size_t count, const char *name)
+{
+	memset(ext, 0, sizeof(*ext));
+
+	ext->ext_type = SIGNED_PKG_INFO_EXT_TYPE;
+	ext->ext_length = SIGNED_PKG_INFO_EXT_SIZE + count * MODULE_SIZE;
+	memcpy(ext->name, name, sizeof(ext->name));
+}
+
+static void subpart_dir_fixup_write_buffer(struct buffer *buf)
+{
+	struct subpart_dir *s = buffer_get(buf);
+	struct subpart_dir_header *h = &s->h;
+	struct subpart_dir_entry *e = &s->e[0];
+
+	size_t count = h->num_entries;
+	size_t offset = 0;
+
+	offset = fix_member(&h->marker, offset, sizeof(h->marker));
+	offset = fix_member(&h->num_entries, offset, sizeof(h->num_entries));
+	offset = fix_member(&h->header_version, offset,
+			    sizeof(h->header_version));
+	offset = fix_member(&h->entry_version, offset,
+			    sizeof(h->entry_version));
+	offset = fix_member(&h->header_length, offset,
+			    sizeof(h->header_length));
+	offset = fix_member(&h->checksum, offset, sizeof(h->checksum));
+	offset += sizeof(h->name);
+
+	uint32_t i;
+
+	for (i = 0; i < count; i++) {
+		offset += sizeof(e[i].name);
+		offset = fix_member(&e[i].offset, offset, sizeof(e[i].offset));
+		offset = fix_member(&e[i].length, offset, sizeof(e[i].length));
+		offset = fix_member(&e[i].rsvd, offset, sizeof(e[i].rsvd));
+	}
+}
+
+static void create_subpart(struct buffer *dst, struct buffer *info[],
+			   size_t count, const char *name)
+{
+	struct buffer subpart_dir_buff;
+	size_t size = SUBPART_DIR_HEADER_SIZE + count * SUBPART_DIR_ENTRY_SIZE;
+
+	alloc_buffer(&subpart_dir_buff, size, "subpart-dir");
+
+	struct subpart_dir_header *h = buffer_get(&subpart_dir_buff);
+	struct subpart_dir_entry *e = (struct subpart_dir_entry *)(h + 1);
+
+	init_subpart_dir_header(h, count, name);
+
+	size_t curr_offset = size;
+	size_t i;
+
+	for (i = 0; i < count; i++) {
+		curr_offset = init_subpart_dir_entry(&e[i], info[i],
+						     curr_offset);
+	}
+
+	alloc_buffer(dst, curr_offset, name);
+	uint8_t *data = buffer_get(dst);
+
+	for (i = 0; i < count; i++) {
+		memcpy(data + e[i].offset, buffer_get(info[i]),
+		       buffer_size(info[i]));
+	}
+
+	h->checksum = calc_checksum(buffer_get(&subpart_dir_buff));
+
+	struct subpart_dir *dir = buffer_get(&subpart_dir_buff);
+
+	print_subpart_dir(dir);
+
+	subpart_dir_fixup_write_buffer(&subpart_dir_buff);
+	memcpy(data, dir, buffer_size(&subpart_dir_buff));
+
+	buffer_delete(&subpart_dir_buff);
+}
+
+static enum ifwi_ret ibbp_dir_add(int type)
+{
+	struct buffer manifest;
+	struct signed_pkg_info_ext *ext;
+	struct buffer ibbl;
+	struct buffer ibb;
+
+#define DUMMY_IBB_SIZE			(4 * KiB)
+
+	assert(type == IBB_TYPE);
+
+	/*
+	 * Entry # 1 - IBBP.man
+	 * Contains manifest header and signed pkg info extension.
+	 */
+	size_t size = MANIFEST_HDR_SIZE + SIGNED_PKG_INFO_EXT_SIZE;
+
+	alloc_buffer(&manifest, size, "IBBP.man");
+
+	struct manifest_header *man_hdr = buffer_get(&manifest);
+
+	init_manifest_header(man_hdr, size);
+
+	ext = (struct signed_pkg_info_ext *)(man_hdr + 1);
+
+	init_signed_pkg_info_ext(ext, 0, subparts[type].name);
+
+	/* Entry # 2 - IBBL */
+	if (buffer_from_file(&ibbl, param.file_name))
+		return COMMAND_ERR;
+
+	/* Entry # 3 - IBB */
+	alloc_buffer(&ibb, DUMMY_IBB_SIZE, "IBB");
+	memset(buffer_get(&ibb), 0xFF, DUMMY_IBB_SIZE);
+
+	/* Create subpartition */
+	struct buffer *info[] = {
+		&manifest, &ibbl, &ibb,
+	};
+	create_subpart(&ifwi_image.subpart_buf[type], &info[0],
+		       ARRAY_SIZE(info), subparts[type].name);
+
+	return REPACK_REQUIRED;
+}
+
+static enum ifwi_ret ifwi_raw_add(int type)
+{
+	if (buffer_from_file(&ifwi_image.subpart_buf[type], param.file_name))
+		return COMMAND_ERR;
+
+	printf("Sub-partition %s(%d) added from file %s.\n", param.subpart_name,
+	       type, param.file_name);
+	return REPACK_REQUIRED;
+}
+
+static enum ifwi_ret ifwi_dir_add(int type)
+{
+	if (!(subparts[type].attr & CONTAINS_DIR) ||
+	    !subparts[type].dir_ops.dir_add) {
+		ERROR("Sub-Partition %s(%d) does not support dir ops.\n",
+		      subparts[type].name, type);
+		return COMMAND_ERR;
+	}
+
+	if (!param.dentry_name) {
+		ERROR("%s: -e option required\n", __func__);
+		return COMMAND_ERR;
+	}
+
+	enum ifwi_ret ret = subparts[type].dir_ops.dir_add(type);
+
+	if (ret != COMMAND_ERR)
+		printf("Sub-partition %s(%d) entry %s added from file %s.\n",
+		       param.subpart_name, type, param.dentry_name,
+		       param.file_name);
+	else
+		ERROR("Sub-partition dir operation failed.\n");
+
+	return ret;
+}
+
+static enum ifwi_ret ifwi_add(void)
+{
+	if (!param.file_name) {
+		ERROR("%s: -f option required\n", __func__);
+		return COMMAND_ERR;
+	}
+
+	if (!param.subpart_name) {
+		ERROR("%s: -n option required\n", __func__);
+		return COMMAND_ERR;
+	}
+
+	int type = find_type_by_name(param.subpart_name);
+
+	if (type == -1)
+		return COMMAND_ERR;
+
+	const struct subpart_info *curr_subpart = &subparts[type];
+
+	if (curr_subpart->attr & AUTO_GENERATED) {
+		ERROR("Cannot add auto-generated sub-partitions.\n");
+		return COMMAND_ERR;
+	}
+
+	if (buffer_size(&ifwi_image.subpart_buf[type])) {
+		ERROR("Image already contains sub-partition %s(%d).\n",
+		      param.subpart_name, type);
+		return COMMAND_ERR;
+	}
+
+	if (param.dir_ops)
+		return ifwi_dir_add(type);
+
+	return ifwi_raw_add(type);
+}
+
+static enum ifwi_ret ifwi_delete(void)
+{
+	if (!param.subpart_name) {
+		ERROR("%s: -n option required\n", __func__);
+		return COMMAND_ERR;
+	}
+
+	int type = find_type_by_name(param.subpart_name);
+
+	if (type == -1)
+		return COMMAND_ERR;
+
+	const struct subpart_info *curr_subpart = &subparts[type];
+
+	if (curr_subpart->attr & AUTO_GENERATED) {
+		ERROR("Cannot delete auto-generated sub-partitions.\n");
+		return COMMAND_ERR;
+	}
+
+	if (buffer_size(&ifwi_image.subpart_buf[type]) == 0) {
+		printf("Image does not contain sub-partition %s(%d).\n",
+		       param.subpart_name, type);
+		return NO_ACTION_REQUIRED;
+	}
+
+	buffer_delete(&ifwi_image.subpart_buf[type]);
+	printf("Sub-Partition %s(%d) deleted.\n", subparts[type].name, type);
+	return REPACK_REQUIRED;
+}
+
+static enum ifwi_ret ifwi_dir_extract(int type)
+{
+	if (!(subparts[type].attr & CONTAINS_DIR)) {
+		ERROR("Sub-Partition %s(%d) does not support dir ops.\n",
+		      subparts[type].name, type);
+		return COMMAND_ERR;
+	}
+
+	if (!param.dentry_name) {
+		ERROR("%s: -e option required.\n", __func__);
+		return COMMAND_ERR;
+	}
+
+	struct buffer subpart_dir_buff;
+
+	parse_subpart_dir(&subpart_dir_buff, &ifwi_image.subpart_buf[type],
+			  subparts[type].name);
+
+	uint32_t i;
+	struct subpart_dir *s = buffer_get(&subpart_dir_buff);
+
+	for (i = 0; i < s->h.num_entries; i++) {
+		if (!strncmp((char *)s->e[i].name, param.dentry_name,
+			     sizeof(s->e[i].name)))
+			break;
+	}
+
+	if (i == s->h.num_entries) {
+		ERROR("Entry %s not found in subpartition for %s.\n",
+		      param.dentry_name, param.subpart_name);
+		exit(-1);
+	}
+
+	struct buffer dst;
+
+	DEBUG("Splicing buffer at 0x%x size 0x%x\n", s->e[i].offset,
+	      s->e[i].length);
+	buffer_splice(&dst, &ifwi_image.subpart_buf[type], s->e[i].offset,
+		      s->e[i].length);
+
+	if (buffer_write_file(&dst, param.file_name))
+		return COMMAND_ERR;
+
+	printf("Sub-Partition %s(%d), entry(%s) stored in %s.\n",
+	       param.subpart_name, type, param.dentry_name, param.file_name);
+
+	return NO_ACTION_REQUIRED;
+}
+
+static enum ifwi_ret ifwi_raw_extract(int type)
+{
+	if (buffer_write_file(&ifwi_image.subpart_buf[type], param.file_name))
+		return COMMAND_ERR;
+
+	printf("Sub-Partition %s(%d) stored in %s.\n", param.subpart_name, type,
+	       param.file_name);
+
+	return NO_ACTION_REQUIRED;
+}
+
+static enum ifwi_ret ifwi_extract(void)
+{
+	if (!param.file_name) {
+		ERROR("%s: -f option required\n", __func__);
+		return COMMAND_ERR;
+	}
+
+	if (!param.subpart_name) {
+		ERROR("%s: -n option required\n", __func__);
+		return COMMAND_ERR;
+	}
+
+	int type = find_type_by_name(param.subpart_name);
+
+	if (type == -1)
+		return COMMAND_ERR;
+
+	if (type == S_BPDT_TYPE) {
+		INFO("Tool does not support raw extract for %s\n",
+		     param.subpart_name);
+		return NO_ACTION_REQUIRED;
+	}
+
+	if (buffer_size(&ifwi_image.subpart_buf[type]) == 0) {
+		ERROR("Image does not contain sub-partition %s(%d).\n",
+		      param.subpart_name, type);
+		return COMMAND_ERR;
+	}
+
+	INFO("Extracting sub-partition %s(%d).\n", param.subpart_name, type);
+	if (param.dir_ops)
+		return ifwi_dir_extract(type);
+
+	return ifwi_raw_extract(type);
+}
+
+static enum ifwi_ret ifwi_print(void)
+{
+	verbose += 2;
+
+	struct bpdt *b = buffer_get(&ifwi_image.bpdt);
+
+	bpdt_print_header(&b->h, "BPDT");
+	bpdt_print_entries(&b->e[0], b->h.descriptor_count, "BPDT");
+
+	b = buffer_get(&ifwi_image.subpart_buf[S_BPDT_TYPE]);
+	bpdt_print_header(&b->h, "S-BPDT");
+	bpdt_print_entries(&b->e[0], b->h.descriptor_count, "S-BPDT");
+
+	if (param.dir_ops == 0) {
+		verbose -= 2;
+		return NO_ACTION_REQUIRED;
+	}
+
+	int i;
+	struct buffer subpart_dir_buf;
+
+	for (i = 0; i < MAX_SUBPARTS ; i++) {
+		if (!(subparts[i].attr & CONTAINS_DIR) ||
+		    (buffer_size(&ifwi_image.subpart_buf[i]) == 0))
+			continue;
+
+		parse_subpart_dir(&subpart_dir_buf, &ifwi_image.subpart_buf[i],
+				  subparts[i].name);
+		buffer_delete(&subpart_dir_buf);
+	}
+
+	verbose -= 2;
+
+	return NO_ACTION_REQUIRED;
+}
+
+static enum ifwi_ret ifwi_raw_replace(int type)
+{
+	buffer_delete(&ifwi_image.subpart_buf[type]);
+	return ifwi_raw_add(type);
+}
+
+static enum ifwi_ret ifwi_dir_replace(int type)
+{
+	if (!(subparts[type].attr & CONTAINS_DIR)) {
+		ERROR("Sub-Partition %s(%d) does not support dir ops.\n",
+		      subparts[type].name, type);
+		return COMMAND_ERR;
+	}
+
+	if (!param.dentry_name) {
+		ERROR("%s: -e option required.\n", __func__);
+		return COMMAND_ERR;
+	}
+
+	struct buffer subpart_dir_buf;
+
+	parse_subpart_dir(&subpart_dir_buf, &ifwi_image.subpart_buf[type],
+			  subparts[type].name);
+
+	uint32_t i;
+	struct subpart_dir *s = buffer_get(&subpart_dir_buf);
+
+	for (i = 0; i < s->h.num_entries; i++) {
+		if (!strcmp((char *)s->e[i].name, param.dentry_name))
+			break;
+	}
+
+	if (i == s->h.num_entries) {
+		ERROR("Entry %s not found in subpartition for %s.\n",
+		      param.dentry_name, param.subpart_name);
+		exit(-1);
+	}
+
+	struct buffer b;
+
+	if (buffer_from_file(&b, param.file_name)) {
+		ERROR("Failed to read %s\n", param.file_name);
+		exit(-1);
+	}
+
+	struct buffer dst;
+	size_t dst_size = buffer_size(&ifwi_image.subpart_buf[type]) +
+				      buffer_size(&b) - s->e[i].length;
+	size_t subpart_start = s->e[i].offset;
+	size_t subpart_end = s->e[i].offset + s->e[i].length;
+
+	alloc_buffer(&dst, dst_size, ifwi_image.subpart_buf[type].name);
+
+	uint8_t *src_data = buffer_get(&ifwi_image.subpart_buf[type]);
+	uint8_t *dst_data = buffer_get(&dst);
+	size_t curr_offset = 0;
+
+	/* Copy data before the sub-partition entry */
+	memcpy(dst_data + curr_offset, src_data, subpart_start);
+	curr_offset += subpart_start;
+
+	/* Copy sub-partition entry */
+	memcpy(dst_data + curr_offset, buffer_get(&b), buffer_size(&b));
+	curr_offset += buffer_size(&b);
+
+	/* Copy remaining data */
+	memcpy(dst_data + curr_offset, src_data + subpart_end,
+	       buffer_size(&ifwi_image.subpart_buf[type]) - subpart_end);
+
+	/* Update sub-partition buffer */
+	int offset = s->e[i].offset;
+
+	buffer_delete(&ifwi_image.subpart_buf[type]);
+	ifwi_image.subpart_buf[type] = dst;
+
+	/* Update length of entry in the subpartition */
+	s->e[i].length = buffer_size(&b);
+	buffer_delete(&b);
+
+	/* Adjust offsets of affected entries in subpartition */
+	offset = s->e[i].offset - offset;
+	for (; i < s->h.num_entries; i++)
+		s->e[i].offset += offset;
+
+	/* Re-calculate checksum */
+	s->h.checksum = calc_checksum(s);
+
+	/* Convert members to litte-endian */
+	subpart_dir_fixup_write_buffer(&subpart_dir_buf);
+
+	memcpy(dst_data, buffer_get(&subpart_dir_buf),
+	       buffer_size(&subpart_dir_buf));
+
+	buffer_delete(&subpart_dir_buf);
+
+	printf("Sub-partition %s(%d) entry %s replaced from file %s.\n",
+	       param.subpart_name, type, param.dentry_name, param.file_name);
+
+	return REPACK_REQUIRED;
+}
+
+static enum ifwi_ret ifwi_replace(void)
+{
+	if (!param.file_name) {
+		ERROR("%s: -f option required\n", __func__);
+		return COMMAND_ERR;
+	}
+
+	if (!param.subpart_name) {
+		ERROR("%s: -n option required\n", __func__);
+		return COMMAND_ERR;
+	}
+
+	int type = find_type_by_name(param.subpart_name);
+
+	if (type == -1)
+		return COMMAND_ERR;
+
+	const struct subpart_info *curr_subpart = &subparts[type];
+
+	if (curr_subpart->attr & AUTO_GENERATED) {
+		ERROR("Cannot replace auto-generated sub-partitions.\n");
+		return COMMAND_ERR;
+	}
+
+	if (buffer_size(&ifwi_image.subpart_buf[type]) == 0) {
+		ERROR("Image does not contain sub-partition %s(%d).\n",
+		      param.subpart_name, type);
+		return COMMAND_ERR;
+	}
+
+	if (param.dir_ops)
+		return ifwi_dir_replace(type);
+
+	return ifwi_raw_replace(type);
+}
+
+static enum ifwi_ret ifwi_create(void)
+{
+	/*
+	 * Create peels off any non-IFWI content present in the input buffer and
+	 * creates output file with only the IFWI present.
+	 */
+
+	if (!param.file_name) {
+		ERROR("%s: -f option required\n", __func__);
+		return COMMAND_ERR;
+	}
+
+	/* Peel off any non-IFWI prefix */
+	buffer_seek(&ifwi_image.input_buff,
+		    ifwi_image.input_ifwi_start_offset);
+	/* Peel off any non-IFWI suffix */
+	buffer_set_size(&ifwi_image.input_buff,
+			ifwi_image.input_ifwi_end_offset -
+			ifwi_image.input_ifwi_start_offset);
+
+	/*
+	 * Adjust start and end offset of IFWI now that non-IFWI prefix is gone.
+	 */
+	ifwi_image.input_ifwi_end_offset -= ifwi_image.input_ifwi_start_offset;
+	ifwi_image.input_ifwi_start_offset = 0;
+
+	param.image_name = param.file_name;
+
+	return REPACK_REQUIRED;
+}
+
+struct command {
+	const char *name;
+	const char *optstring;
+	enum ifwi_ret (*function)(void);
+};
+
+static const struct command commands[] = {
+	{"add", "f:n:e:dvh?", ifwi_add},
+	{"create", "f:vh?", ifwi_create},
+	{"delete", "f:n:vh?", ifwi_delete},
+	{"extract", "f:n:e:dvh?", ifwi_extract},
+	{"print", "dh?", ifwi_print},
+	{"replace", "f:n:e:dvh?", ifwi_replace},
+};
+
+static struct option long_options[] = {
+	{"subpart_dentry",  required_argument, 0, 'e'},
+	{"file",	    required_argument, 0, 'f'},
+	{"help",	    required_argument, 0, 'h'},
+	{"name",	    required_argument, 0, 'n'},
+	{"dir_ops",         no_argument,       0, 'd'},
+	{"verbose",	    no_argument,       0, 'v'},
+	{NULL,		    0,                 0,  0 }
+};
+
+static void usage(const char *name)
+{
+	printf("ifwitool: Utility for IFWI manipulation\n\n"
+	       "USAGE:\n"
+	       " %s [-h]\n"
+	       " %s FILE COMMAND [PARAMETERS]\n\n"
+	       "COMMANDs:\n"
+	       " add -f FILE -n NAME [-d -e ENTRY]\n"
+	       " create -f FILE\n"
+	       " delete -n NAME\n"
+	       " extract -f FILE -n NAME [-d -e ENTRY]\n"
+	       " print [-d]\n"
+	       " replace -f FILE -n NAME [-d -e ENTRY]\n"
+	       "OPTIONs:\n"
+	       " -f FILE : File to read/write/create/extract\n"
+	       " -d      : Perform directory operation\n"
+	       " -e ENTRY: Name of directory entry to operate on\n"
+	       " -v      : Verbose level\n"
+	       " -h      : Help message\n"
+	       " -n NAME : Name of sub-partition to operate on\n",
+	       name, name
+	       );
+
+	printf("\nNAME should be one of:\n");
+	int i;
+
+	for (i = 0; i < MAX_SUBPARTS; i++)
+		printf("%s(%s)\n", subparts[i].name, subparts[i].readable_name);
+	printf("\n");
+}
+
+int main(int argc, char **argv)
+{
+	if (argc < 3) {
+		usage(argv[0]);
+		return 1;
+	}
+
+	param.image_name = argv[1];
+	char *cmd = argv[2];
+
+	optind += 2;
+
+	uint32_t i;
+
+	for (i = 0; i < ARRAY_SIZE(commands); i++) {
+		if (strcmp(cmd, commands[i].name) != 0)
+			continue;
+
+		int c;
+
+		while (1) {
+			int option_index;
+
+			c = getopt_long(argc, argv, commands[i].optstring,
+					long_options, &option_index);
+
+			if (c == -1)
+				break;
+
+			/* Filter out illegal long options */
+			if (!strchr(commands[i].optstring, c)) {
+				ERROR("%s: invalid option -- '%c'\n", argv[0],
+				      c);
+				c = '?';
+			}
+
+			switch (c) {
+			case 'n':
+				param.subpart_name = optarg;
+				break;
+			case 'f':
+				param.file_name = optarg;
+				break;
+			case 'd':
+				param.dir_ops = 1;
+				break;
+			case 'e':
+				param.dentry_name = optarg;
+				break;
+			case 'v':
+				verbose++;
+				break;
+			case 'h':
+			case '?':
+				usage(argv[0]);
+				return 1;
+			default:
+				break;
+			}
+		}
+
+		if (ifwi_parse()) {
+			ERROR("%s: ifwi parsing failed\n", argv[0]);
+			return 1;
+		}
+
+		enum ifwi_ret ret = commands[i].function();
+
+		if (ret == COMMAND_ERR) {
+			ERROR("%s: failed execution\n", argv[0]);
+			return 1;
+		}
+
+		if (ret == REPACK_REQUIRED)
+			ifwi_repack();
+
+		return 0;
+	}
+
+	ERROR("%s: invalid command\n", argv[0]);
+	return 1;
+}