diff --git a/tools/Makefile b/tools/Makefile
index 8ff9c2e..98414f7 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -58,7 +58,8 @@
 FIT_SIG_OBJS-$(CONFIG_FIT_SIGNATURE) := common/image-sig.o
 # Flattened device tree objects
 LIBFDT_OBJS := $(addprefix lib/libfdt/, \
-			fdt.o fdt_ro.o fdt_rw.o fdt_strerror.o fdt_wip.o)
+			fdt.o fdt_ro.o fdt_rw.o fdt_strerror.o fdt_wip.o \
+			fdt_region.o)
 RSA_OBJS-$(CONFIG_FIT_SIGNATURE) := $(addprefix lib/rsa/, \
 					rsa-sign.o rsa-verify.o rsa-checksum.o \
 					rsa-mod-exp.o)
@@ -155,6 +156,9 @@
 hostprogs-y += proftool
 hostprogs-$(CONFIG_STATIC_RELA) += relocate-rela
 
+hostprogs-y += fdtgrep
+fdtgrep-objs += $(LIBFDT_OBJS) fdtgrep.o
+
 # We build some files with extra pedantic flags to try to minimize things
 # that won't build on some weird host compiler -- though there are lots of
 # exceptions for files that aren't complaint.
diff --git a/tools/fdtgrep.c b/tools/fdtgrep.c
new file mode 100644
index 0000000..caaf600
--- /dev/null
+++ b/tools/fdtgrep.c
@@ -0,0 +1,1234 @@
+/*
+ * Copyright (c) 2013, Google Inc.
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ *
+ * Perform a grep of an FDT either displaying the source subset or producing
+ * a new .dtb subset which can be used as required.
+ */
+
+#include <assert.h>
+#include <ctype.h>
+#include <getopt.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <../include/libfdt.h>
+#include <libfdt_internal.h>
+
+/* Define DEBUG to get some debugging output on stderr */
+#ifdef DEBUG
+#define debug(a, b...) fprintf(stderr, a, ## b)
+#else
+#define debug(a, b...)
+#endif
+
+/* A linked list of values we are grepping for */
+struct value_node {
+	int type;		/* Types this value matches (FDT_IS... mask) */
+	int include;		/* 1 to include matches, 0 to exclude */
+	const char *string;	/* String to match */
+	struct value_node *next;	/* Pointer to next node, or NULL */
+};
+
+/* Output formats we support */
+enum output_t {
+	OUT_DTS,		/* Device tree source */
+	OUT_DTB,		/* Valid device tree binary */
+	OUT_BIN,		/* Fragment of .dtb, for hashing */
+};
+
+/* Holds information which controls our output and options */
+struct display_info {
+	enum output_t output;	/* Output format */
+	int add_aliases;	/* Add aliases node to output */
+	int all;		/* Display all properties/nodes */
+	int colour;		/* Display output in ANSI colour */
+	int region_list;	/* Output a region list */
+	int flags;		/* Flags (FDT_REG_...) */
+	int list_strings;	/* List strings in string table */
+	int show_offset;	/* Show offset */
+	int show_addr;		/* Show address */
+	int header;		/* Output an FDT header */
+	int diff;		/* Show +/- diff markers */
+	int include_root;	/* Include the root node and all properties */
+	int remove_strings;	/* Remove unused strings */
+	int show_dts_version;	/* Put '/dts-v1/;' on the first line */
+	int types_inc;		/* Mask of types that we include (FDT_IS...) */
+	int types_exc;		/* Mask of types that we exclude (FDT_IS...) */
+	int invert;		/* Invert polarity of match */
+	struct value_node *value_head;	/* List of values to match */
+	const char *output_fname;	/* Output filename */
+	FILE *fout;		/* File to write dts/dtb output */
+};
+
+static void report_error(const char *where, int err)
+{
+	fprintf(stderr, "Error at '%s': %s\n", where, fdt_strerror(err));
+}
+
+/* Supported ANSI colours */
+enum {
+	COL_BLACK,
+	COL_RED,
+	COL_GREEN,
+	COL_YELLOW,
+	COL_BLUE,
+	COL_MAGENTA,
+	COL_CYAN,
+	COL_WHITE,
+
+	COL_NONE = -1,
+};
+
+/**
+ * print_ansi_colour() - Print out the ANSI sequence for a colour
+ *
+ * @fout:	Output file
+ * @col:	Colour to output (COL_...), or COL_NONE to reset colour
+ */
+static void print_ansi_colour(FILE *fout, int col)
+{
+	if (col == COL_NONE)
+		fprintf(fout, "\033[0m");
+	else
+		fprintf(fout, "\033[1;%dm", col + 30);
+}
+
+
+/**
+ * value_add() - Add a new value to our list of things to grep for
+ *
+ * @disp:	Display structure, holding info about our options
+ * @headp:	Pointer to header pointer of list
+ * @type:	Type of this value (FDT_IS_...)
+ * @include:	1 if we want to include matches, 0 to exclude
+ * @str:	String value to match
+ */
+static int value_add(struct display_info *disp, struct value_node **headp,
+		     int type, int include, const char *str)
+{
+	struct value_node *node;
+
+	/*
+	 * Keep track of which types we are excluding/including. We don't
+	 * allow both including and excluding things, because it doesn't make
+	 * sense. 'Including' means that everything not mentioned is
+	 * excluded. 'Excluding' means that everything not mentioned is
+	 * included. So using the two together would be meaningless.
+	 */
+	if (include)
+		disp->types_inc |= type;
+	else
+		disp->types_exc |= type;
+	if (disp->types_inc & disp->types_exc & type) {
+		fprintf(stderr,
+			"Cannot use both include and exclude for '%s'\n", str);
+		return -1;
+	}
+
+	str = strdup(str);
+	node = malloc(sizeof(*node));
+	if (!str || !node) {
+		fprintf(stderr, "Out of memory\n");
+		return -1;
+	}
+	node->next = *headp;
+	node->type = type;
+	node->include = include;
+	node->string = str;
+	*headp = node;
+
+	return 0;
+}
+
+static bool util_is_printable_string(const void *data, int len)
+{
+	const char *s = data;
+	const char *ss, *se;
+
+	/* zero length is not */
+	if (len == 0)
+		return 0;
+
+	/* must terminate with zero */
+	if (s[len - 1] != '\0')
+		return 0;
+
+	se = s + len;
+
+	while (s < se) {
+		ss = s;
+		while (s < se && *s && isprint((unsigned char)*s))
+			s++;
+
+		/* not zero, or not done yet */
+		if (*s != '\0' || s == ss)
+			return 0;
+
+		s++;
+	}
+
+	return 1;
+}
+
+static void utilfdt_print_data(const char *data, int len)
+{
+	int i;
+	const char *p = data;
+	const char *s;
+
+	/* no data, don't print */
+	if (len == 0)
+		return;
+
+	if (util_is_printable_string(data, len)) {
+		printf(" = ");
+
+		s = data;
+		do {
+			printf("\"%s\"", s);
+			s += strlen(s) + 1;
+			if (s < data + len)
+				printf(", ");
+		} while (s < data + len);
+
+	} else if ((len % 4) == 0) {
+		const uint32_t *cell = (const uint32_t *)data;
+
+		printf(" = <");
+		for (i = 0, len /= 4; i < len; i++)
+			printf("0x%08x%s", fdt32_to_cpu(cell[i]),
+			       i < (len - 1) ? " " : "");
+		printf(">");
+	} else {
+		printf(" = [");
+		for (i = 0; i < len; i++)
+			printf("%02x%s", *p++, i < len - 1 ? " " : "");
+		printf("]");
+	}
+}
+
+/**
+ * display_fdt_by_regions() - Display regions of an FDT source
+ *
+ * This dumps an FDT as source, but only certain regions of it. This is the
+ * final stage of the grep - we have a list of regions we want to display,
+ * and this function displays them.
+ *
+ * @disp:	Display structure, holding info about our options
+ * @blob:	FDT blob to display
+ * @region:	List of regions to display
+ * @count:	Number of regions
+ */
+static int display_fdt_by_regions(struct display_info *disp, const void *blob,
+		struct fdt_region region[], int count)
+{
+	struct fdt_region *reg = region, *reg_end = region + count;
+	uint32_t off_mem_rsvmap = fdt_off_mem_rsvmap(blob);
+	int base = fdt_off_dt_struct(blob);
+	int version = fdt_version(blob);
+	int offset, nextoffset;
+	int tag, depth, shift;
+	FILE *f = disp->fout;
+	uint64_t addr, size;
+	int in_region;
+	int file_ofs;
+	int i;
+
+	if (disp->show_dts_version)
+		fprintf(f, "/dts-v1/;\n");
+
+	if (disp->header) {
+		fprintf(f, "// magic:\t\t0x%x\n", fdt_magic(blob));
+		fprintf(f, "// totalsize:\t\t0x%x (%d)\n", fdt_totalsize(blob),
+			fdt_totalsize(blob));
+		fprintf(f, "// off_dt_struct:\t0x%x\n",
+			fdt_off_dt_struct(blob));
+		fprintf(f, "// off_dt_strings:\t0x%x\n",
+			fdt_off_dt_strings(blob));
+		fprintf(f, "// off_mem_rsvmap:\t0x%x\n", off_mem_rsvmap);
+		fprintf(f, "// version:\t\t%d\n", version);
+		fprintf(f, "// last_comp_version:\t%d\n",
+			fdt_last_comp_version(blob));
+		if (version >= 2) {
+			fprintf(f, "// boot_cpuid_phys:\t0x%x\n",
+				fdt_boot_cpuid_phys(blob));
+		}
+		if (version >= 3) {
+			fprintf(f, "// size_dt_strings:\t0x%x\n",
+				fdt_size_dt_strings(blob));
+		}
+		if (version >= 17) {
+			fprintf(f, "// size_dt_struct:\t0x%x\n",
+				fdt_size_dt_struct(blob));
+		}
+		fprintf(f, "\n");
+	}
+
+	if (disp->flags & FDT_REG_ADD_MEM_RSVMAP) {
+		const struct fdt_reserve_entry *p_rsvmap;
+
+		p_rsvmap = (const struct fdt_reserve_entry *)
+				((const char *)blob + off_mem_rsvmap);
+		for (i = 0; ; i++) {
+			addr = fdt64_to_cpu(p_rsvmap[i].address);
+			size = fdt64_to_cpu(p_rsvmap[i].size);
+			if (addr == 0 && size == 0)
+				break;
+
+			fprintf(f, "/memreserve/ %llx %llx;\n",
+				(unsigned long long)addr,
+				(unsigned long long)size);
+		}
+	}
+
+	depth = 0;
+	nextoffset = 0;
+	shift = 4;	/* 4 spaces per indent */
+	do {
+		const struct fdt_property *prop;
+		const char *name;
+		int show;
+		int len;
+
+		offset = nextoffset;
+
+		/*
+		 * Work out the file offset of this offset, and decide
+		 * whether it is in the region list or not
+		 */
+		file_ofs = base + offset;
+		if (reg < reg_end && file_ofs >= reg->offset + reg->size)
+			reg++;
+		in_region = reg < reg_end && file_ofs >= reg->offset &&
+				file_ofs < reg->offset + reg->size;
+		tag = fdt_next_tag(blob, offset, &nextoffset);
+
+		if (tag == FDT_END)
+			break;
+		show = in_region || disp->all;
+		if (show && disp->diff)
+			fprintf(f, "%c", in_region ? '+' : '-');
+
+		if (!show) {
+			/* Do this here to avoid 'if (show)' in every 'case' */
+			if (tag == FDT_BEGIN_NODE)
+				depth++;
+			else if (tag == FDT_END_NODE)
+				depth--;
+			continue;
+		}
+		if (tag != FDT_END) {
+			if (disp->show_addr)
+				fprintf(f, "%4x: ", file_ofs);
+			if (disp->show_offset)
+				fprintf(f, "%4x: ", file_ofs - base);
+		}
+
+		/* Green means included, red means excluded */
+		if (disp->colour)
+			print_ansi_colour(f, in_region ? COL_GREEN : COL_RED);
+
+		switch (tag) {
+		case FDT_PROP:
+			prop = fdt_get_property_by_offset(blob, offset, NULL);
+			name = fdt_string(blob, fdt32_to_cpu(prop->nameoff));
+			fprintf(f, "%*s%s", depth * shift, "", name);
+			utilfdt_print_data(prop->data,
+					   fdt32_to_cpu(prop->len));
+			fprintf(f, ";");
+			break;
+
+		case FDT_NOP:
+			fprintf(f, "%*s// [NOP]", depth * shift, "");
+			break;
+
+		case FDT_BEGIN_NODE:
+			name = fdt_get_name(blob, offset, &len);
+			fprintf(f, "%*s%s {", depth++ * shift, "",
+				*name ? name : "/");
+			break;
+
+		case FDT_END_NODE:
+			fprintf(f, "%*s};", --depth * shift, "");
+			break;
+		}
+
+		/* Reset colour back to normal before end of line */
+		if (disp->colour)
+			print_ansi_colour(f, COL_NONE);
+		fprintf(f, "\n");
+	} while (1);
+
+	/* Print a list of strings if requested */
+	if (disp->list_strings) {
+		const char *str;
+		int str_base = fdt_off_dt_strings(blob);
+
+		for (offset = 0; offset < fdt_size_dt_strings(blob);
+				offset += strlen(str) + 1) {
+			str = fdt_string(blob, offset);
+			int len = strlen(str) + 1;
+			int show;
+
+			/* Only print strings that are in the region */
+			file_ofs = str_base + offset;
+			in_region = reg < reg_end &&
+					file_ofs >= reg->offset &&
+					file_ofs + len < reg->offset +
+						reg->size;
+			show = in_region || disp->all;
+			if (show && disp->diff)
+				printf("%c", in_region ? '+' : '-');
+			if (disp->show_addr)
+				printf("%4x: ", file_ofs);
+			if (disp->show_offset)
+				printf("%4x: ", offset);
+			printf("%s\n", str);
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * dump_fdt_regions() - Dump regions of an FDT as binary data
+ *
+ * This dumps an FDT as binary, but only certain regions of it. This is the
+ * final stage of the grep - we have a list of regions we want to dump,
+ * and this function dumps them.
+ *
+ * The output of this function may or may not be a valid FDT. To ensure it
+ * is, these disp->flags must be set:
+ *
+ *   FDT_REG_SUPERNODES: ensures that subnodes are preceeded by their
+ *		parents. Without this option, fragments of subnode data may be
+ *		output without the supernodes above them. This is useful for
+ *		hashing but cannot produce a valid FDT.
+ *   FDT_REG_ADD_STRING_TAB: Adds a string table to the end of the FDT.
+ *		Without this none of the properties will have names
+ *   FDT_REG_ADD_MEM_RSVMAP: Adds a mem_rsvmap table - an FDT is invalid
+ *		without this.
+ *
+ * @disp:	Display structure, holding info about our options
+ * @blob:	FDT blob to display
+ * @region:	List of regions to display
+ * @count:	Number of regions
+ * @out:	Output destination
+ */
+static int dump_fdt_regions(struct display_info *disp, const void *blob,
+		struct fdt_region region[], int count, char *out)
+{
+	struct fdt_header *fdt;
+	int size, struct_start;
+	int ptr;
+	int i;
+
+	/* Set up a basic header (even if we don't actually write it) */
+	fdt = (struct fdt_header *)out;
+	memset(fdt, '\0', sizeof(*fdt));
+	fdt_set_magic(fdt, FDT_MAGIC);
+	struct_start = FDT_ALIGN(sizeof(struct fdt_header),
+					sizeof(struct fdt_reserve_entry));
+	fdt_set_off_mem_rsvmap(fdt, struct_start);
+	fdt_set_version(fdt, FDT_LAST_SUPPORTED_VERSION);
+	fdt_set_last_comp_version(fdt, FDT_FIRST_SUPPORTED_VERSION);
+
+	/*
+	 * Calculate the total size of the regions we are writing out. The
+	 * first will be the mem_rsvmap if the FDT_REG_ADD_MEM_RSVMAP flag
+	 * is set. The last will be the string table if FDT_REG_ADD_STRING_TAB
+	 * is set.
+	 */
+	for (i = size = 0; i < count; i++)
+		size += region[i].size;
+
+	/* Bring in the mem_rsvmap section from the old file if requested */
+	if (count > 0 && (disp->flags & FDT_REG_ADD_MEM_RSVMAP)) {
+		struct_start += region[0].size;
+		size -= region[0].size;
+	}
+	fdt_set_off_dt_struct(fdt, struct_start);
+
+	/* Update the header to have the correct offsets/sizes */
+	if (count >= 2 && (disp->flags & FDT_REG_ADD_STRING_TAB)) {
+		int str_size;
+
+		str_size = region[count - 1].size;
+		fdt_set_size_dt_struct(fdt, size - str_size);
+		fdt_set_off_dt_strings(fdt, struct_start + size - str_size);
+		fdt_set_size_dt_strings(fdt, str_size);
+		fdt_set_totalsize(fdt, struct_start + size);
+	}
+
+	/* Write the header if required */
+	ptr = 0;
+	if (disp->header) {
+		ptr = sizeof(*fdt);
+		while (ptr < fdt_off_mem_rsvmap(fdt))
+			out[ptr++] = '\0';
+	}
+
+	/* Output all the nodes including any mem_rsvmap/string table */
+	for (i = 0; i < count; i++) {
+		struct fdt_region *reg = &region[i];
+
+		memcpy(out + ptr, (const char *)blob + reg->offset, reg->size);
+		ptr += reg->size;
+	}
+
+	return ptr;
+}
+
+/**
+ * show_region_list() - Print out a list of regions
+ *
+ * The list includes the region offset (absolute offset from start of FDT
+ * blob in bytes) and size
+ *
+ * @reg:	List of regions to print
+ * @count:	Number of regions
+ */
+static void show_region_list(struct fdt_region *reg, int count)
+{
+	int i;
+
+	printf("Regions: %d\n", count);
+	for (i = 0; i < count; i++, reg++) {
+		printf("%d:  %-10x  %-10x\n", i, reg->offset,
+		       reg->offset + reg->size);
+	}
+}
+
+static int check_type_include(void *priv, int type, const char *data, int size)
+{
+	struct display_info *disp = priv;
+	struct value_node *val;
+	int match, none_match = FDT_IS_ANY;
+
+	/* If none of our conditions mention this type, we know nothing */
+	debug("type=%x, data=%s\n", type, data ? data : "(null)");
+	if (!((disp->types_inc | disp->types_exc) & type)) {
+		debug("   - not in any condition\n");
+		return -1;
+	}
+
+	/*
+	 * Go through the list of conditions. For inclusive conditions, we
+	 * return 1 at the first match. For exclusive conditions, we must
+	 * check that there are no matches.
+	 */
+	for (val = disp->value_head; val; val = val->next) {
+		if (!(type & val->type))
+			continue;
+		match = fdt_stringlist_contains(data, size, val->string);
+		debug("      - val->type=%x, str='%s', match=%d\n",
+		      val->type, val->string, match);
+		if (match && val->include) {
+			debug("   - match inc %s\n", val->string);
+			return 1;
+		}
+		if (match)
+			none_match &= ~val->type;
+	}
+
+	/*
+	 * If this is an exclusive condition, and nothing matches, then we
+	 * should return 1.
+	 */
+	if ((type & disp->types_exc) && (none_match & type)) {
+		debug("   - match exc\n");
+		/*
+		 * Allow FDT_IS_COMPAT to make the final decision in the
+		 * case where there is no specific type
+		 */
+		if (type == FDT_IS_NODE && disp->types_exc == FDT_ANY_GLOBAL) {
+			debug("   - supressed exc node\n");
+			return -1;
+		}
+		return 1;
+	}
+
+	/*
+	 * Allow FDT_IS_COMPAT to make the final decision in the
+	 * case where there is no specific type (inclusive)
+	 */
+	if (type == FDT_IS_NODE && disp->types_inc == FDT_ANY_GLOBAL)
+		return -1;
+
+	debug("   - no match, types_inc=%x, types_exc=%x, none_match=%x\n",
+	      disp->types_inc, disp->types_exc, none_match);
+
+	return 0;
+}
+
+/**
+ * h_include() - Include handler function for fdt_find_regions()
+ *
+ * This function decides whether to include or exclude a node, property or
+ * compatible string. The function is defined by fdt_find_regions().
+ *
+ * The algorithm is documented in the code - disp->invert is 0 for normal
+ * operation, and 1 to invert the sense of all matches.
+ *
+ * See
+ */
+static int h_include(void *priv, const void *fdt, int offset, int type,
+		     const char *data, int size)
+{
+	struct display_info *disp = priv;
+	int inc, len;
+
+	inc = check_type_include(priv, type, data, size);
+	if (disp->include_root && type == FDT_IS_PROP && offset == 0 && inc)
+		return 1;
+
+	/*
+	 * If the node name does not tell us anything, check the
+	 * compatible string
+	 */
+	if (inc == -1 && type == FDT_IS_NODE) {
+		debug("   - checking compatible2\n");
+		data = fdt_getprop(fdt, offset, "compatible", &len);
+		inc = check_type_include(priv, FDT_IS_COMPAT, data, len);
+	}
+
+	/* If we still have no idea, check for properties in the node */
+	if (inc != 1 && type == FDT_IS_NODE &&
+	    (disp->types_inc & FDT_NODE_HAS_PROP)) {
+		debug("   - checking node '%s'\n",
+		      fdt_get_name(fdt, offset, NULL));
+		for (offset = fdt_first_property_offset(fdt, offset);
+		     offset > 0 && inc != 1;
+		     offset = fdt_next_property_offset(fdt, offset)) {
+			const struct fdt_property *prop;
+			const char *str;
+
+			prop = fdt_get_property_by_offset(fdt, offset, NULL);
+			if (!prop)
+				continue;
+			str = fdt_string(fdt, fdt32_to_cpu(prop->nameoff));
+			inc = check_type_include(priv, FDT_NODE_HAS_PROP, str,
+						 strlen(str));
+		}
+		if (inc == -1)
+			inc = 0;
+	}
+
+	switch (inc) {
+	case 1:
+		inc = !disp->invert;
+		break;
+	case 0:
+		inc = disp->invert;
+		break;
+	}
+	debug("   - returning %d\n", inc);
+
+	return inc;
+}
+
+static int h_cmp_region(const void *v1, const void *v2)
+{
+	const struct fdt_region *region1 = v1, *region2 = v2;
+
+	return region1->offset - region2->offset;
+}
+
+static int fdtgrep_find_regions(const void *fdt,
+		int (*include_func)(void *priv, const void *fdt, int offset,
+				 int type, const char *data, int size),
+		struct display_info *disp, struct fdt_region *region,
+		int max_regions, char *path, int path_len, int flags)
+{
+	struct fdt_region_state state;
+	int count;
+	int ret;
+
+	count = 0;
+	ret = fdt_first_region(fdt, include_func, disp,
+			&region[count++], path, path_len,
+			disp->flags, &state);
+	while (ret == 0) {
+		ret = fdt_next_region(fdt, include_func, disp,
+				count < max_regions ? &region[count] : NULL,
+				path, path_len, disp->flags, &state);
+		if (!ret)
+			count++;
+	}
+
+	/* Find all the aliases and add those regions back in */
+	if (disp->add_aliases && count < max_regions) {
+		int new_count;
+
+		new_count = fdt_add_alias_regions(fdt, region, count,
+						  max_regions, &state);
+		if (new_count > max_regions) {
+			region = malloc(new_count * sizeof(struct fdt_region));
+			if (!region) {
+				fprintf(stderr,
+					"Out of memory for %d regions\n",
+					count);
+				return -1;
+			}
+			memcpy(region, state.region,
+			       count * sizeof(struct fdt_region));
+			free(state.region);
+			new_count = fdt_add_alias_regions(fdt, region, count,
+							  max_regions, &state);
+		}
+
+		/*
+		 * The alias regions will now be at the end of the list. Sort
+		 * the regions by offset to get things into the right order
+		 */
+		qsort(region, new_count, sizeof(struct fdt_region),
+		      h_cmp_region);
+		count = new_count;
+	}
+
+	if (ret != -FDT_ERR_NOTFOUND)
+		return ret;
+
+	return count;
+}
+
+int utilfdt_read_err_len(const char *filename, char **buffp, off_t *len)
+{
+	int fd = 0;	/* assume stdin */
+	char *buf = NULL;
+	off_t bufsize = 1024, offset = 0;
+	int ret = 0;
+
+	*buffp = NULL;
+	if (strcmp(filename, "-") != 0) {
+		fd = open(filename, O_RDONLY);
+		if (fd < 0)
+			return errno;
+	}
+
+	/* Loop until we have read everything */
+	buf = malloc(bufsize);
+	if (!buf)
+		return -ENOMEM;
+	do {
+		/* Expand the buffer to hold the next chunk */
+		if (offset == bufsize) {
+			bufsize *= 2;
+			buf = realloc(buf, bufsize);
+			if (!buf)
+				return -ENOMEM;
+		}
+
+		ret = read(fd, &buf[offset], bufsize - offset);
+		if (ret < 0) {
+			ret = errno;
+			break;
+		}
+		offset += ret;
+	} while (ret != 0);
+
+	/* Clean up, including closing stdin; return errno on error */
+	close(fd);
+	if (ret)
+		free(buf);
+	else
+		*buffp = buf;
+	*len = bufsize;
+	return ret;
+}
+
+int utilfdt_read_err(const char *filename, char **buffp)
+{
+	off_t len;
+	return utilfdt_read_err_len(filename, buffp, &len);
+}
+
+char *utilfdt_read_len(const char *filename, off_t *len)
+{
+	char *buff;
+	int ret = utilfdt_read_err_len(filename, &buff, len);
+
+	if (ret) {
+		fprintf(stderr, "Couldn't open blob from '%s': %s\n", filename,
+			strerror(ret));
+		return NULL;
+	}
+	/* Successful read */
+	return buff;
+}
+
+char *utilfdt_read(const char *filename)
+{
+	off_t len;
+	return utilfdt_read_len(filename, &len);
+}
+
+/**
+ * Run the main fdtgrep operation, given a filename and valid arguments
+ *
+ * @param disp		Display information / options
+ * @param filename	Filename of blob file
+ * @param return 0 if ok, -ve on error
+ */
+static int do_fdtgrep(struct display_info *disp, const char *filename)
+{
+	struct fdt_region *region;
+	int max_regions;
+	int count = 100;
+	char path[1024];
+	char *blob;
+	int i, ret;
+
+	blob = utilfdt_read(filename);
+	if (!blob)
+		return -1;
+	ret = fdt_check_header(blob);
+	if (ret) {
+		fprintf(stderr, "Error: %s\n", fdt_strerror(ret));
+		return ret;
+	}
+
+	/* Allow old files, but they are untested */
+	if (fdt_version(blob) < 17 && disp->value_head) {
+		fprintf(stderr,
+			"Warning: fdtgrep does not fully support version %d files\n",
+			fdt_version(blob));
+	}
+
+	/*
+	 * We do two passes, since we don't know how many regions we need.
+	 * The first pass will count the regions, but if it is too many,
+	 * we do another pass to actually record them.
+	 */
+	for (i = 0; i < 2; i++) {
+		region = malloc(count * sizeof(struct fdt_region));
+		if (!region) {
+			fprintf(stderr, "Out of memory for %d regions\n",
+				count);
+			return -1;
+		}
+		max_regions = count;
+		count = fdtgrep_find_regions(blob,
+				h_include, disp,
+				region, max_regions, path, sizeof(path),
+				disp->flags);
+		if (count < 0) {
+			report_error("fdt_find_regions", count);
+			return -1;
+		}
+		if (count <= max_regions)
+			break;
+		free(region);
+	}
+
+	/* Optionally print a list of regions */
+	if (disp->region_list)
+		show_region_list(region, count);
+
+	/* Output either source .dts or binary .dtb */
+	if (disp->output == OUT_DTS) {
+		ret = display_fdt_by_regions(disp, blob, region, count);
+	} else {
+		void *fdt;
+		/* Allow reserved memory section to expand slightly */
+		int size = fdt_totalsize(blob) + 16;
+
+		fdt = malloc(size);
+		if (!fdt) {
+			fprintf(stderr, "Out_of_memory\n");
+			ret = -1;
+			goto err;
+		}
+		size = dump_fdt_regions(disp, blob, region, count, fdt);
+		if (disp->remove_strings) {
+			void *out;
+
+			out = malloc(size);
+			if (!out) {
+				fprintf(stderr, "Out_of_memory\n");
+				ret = -1;
+				goto err;
+			}
+			ret = fdt_remove_unused_strings(fdt, out);
+			if (ret < 0) {
+				fprintf(stderr,
+					"Failed to remove unused strings: err=%d\n",
+					ret);
+				goto err;
+			}
+			free(fdt);
+			fdt = out;
+			ret = fdt_pack(fdt);
+			if (ret < 0) {
+				fprintf(stderr, "Failed to pack: err=%d\n",
+					ret);
+				goto err;
+			}
+			size = fdt_totalsize(fdt);
+		}
+
+		if (size != fwrite(fdt, 1, size, disp->fout)) {
+			fprintf(stderr, "Write failure, %d bytes\n", size);
+			free(fdt);
+			ret = 1;
+			goto err;
+		}
+		free(fdt);
+	}
+err:
+	free(blob);
+	free(region);
+
+	return ret;
+}
+
+static const char usage_synopsis[] =
+	"fdtgrep - extract portions from device tree\n"
+	"\n"
+	"Usage:\n"
+	"	fdtgrep <options> <dt file>|-\n\n"
+	"Output formats are:\n"
+	"\tdts - device tree soure text\n"
+	"\tdtb - device tree blob (sets -Hmt automatically)\n"
+	"\tbin - device tree fragment (may not be a valid .dtb)";
+
+/* Helper for usage_short_opts string constant */
+#define USAGE_COMMON_SHORT_OPTS "hV"
+
+/* Helper for aligning long_opts array */
+#define a_argument required_argument
+
+/* Helper for usage_long_opts option array */
+#define USAGE_COMMON_LONG_OPTS \
+	{"help",      no_argument, NULL, 'h'}, \
+	{"version",   no_argument, NULL, 'V'}, \
+	{NULL,        no_argument, NULL, 0x0}
+
+/* Helper for usage_opts_help array */
+#define USAGE_COMMON_OPTS_HELP \
+	"Print this help and exit", \
+	"Print version and exit", \
+	NULL
+
+/* Helper for getopt case statements */
+#define case_USAGE_COMMON_FLAGS \
+	case 'h': usage(NULL); \
+	case 'V': util_version(); \
+	case '?': usage("unknown option");
+
+static const char usage_short_opts[] =
+		"haAc:b:C:defg:G:HIlLmn:N:o:O:p:P:rRsStTv"
+		USAGE_COMMON_SHORT_OPTS;
+static struct option const usage_long_opts[] = {
+	{"show-address",	no_argument, NULL, 'a'},
+	{"colour",		no_argument, NULL, 'A'},
+	{"include-node-with-prop", a_argument, NULL, 'b'},
+	{"include-compat",	a_argument, NULL, 'c'},
+	{"exclude-compat",	a_argument, NULL, 'C'},
+	{"diff",		no_argument, NULL, 'd'},
+	{"enter-node",		no_argument, NULL, 'e'},
+	{"show-offset",		no_argument, NULL, 'f'},
+	{"include-match",	a_argument, NULL, 'g'},
+	{"exclude-match",	a_argument, NULL, 'G'},
+	{"show-header",		no_argument, NULL, 'H'},
+	{"show-version",	no_argument, NULL, 'I'},
+	{"list-regions",	no_argument, NULL, 'l'},
+	{"list-strings",	no_argument, NULL, 'L'},
+	{"include-mem",		no_argument, NULL, 'm'},
+	{"include-node",	a_argument, NULL, 'n'},
+	{"exclude-node",	a_argument, NULL, 'N'},
+	{"include-prop",	a_argument, NULL, 'p'},
+	{"exclude-prop",	a_argument, NULL, 'P'},
+	{"remove-strings",	no_argument, NULL, 'r'},
+	{"include-root",	no_argument, NULL, 'R'},
+	{"show-subnodes",	no_argument, NULL, 's'},
+	{"skip-supernodes",	no_argument, NULL, 'S'},
+	{"show-stringtab",	no_argument, NULL, 't'},
+	{"show-aliases",	no_argument, NULL, 'T'},
+	{"out",			a_argument, NULL, 'o'},
+	{"out-format",		a_argument, NULL, 'O'},
+	{"invert-match",	no_argument, NULL, 'v'},
+	USAGE_COMMON_LONG_OPTS,
+};
+static const char * const usage_opts_help[] = {
+	"Display address",
+	"Show all nodes/tags, colour those that match",
+	"Include contains containing property",
+	"Compatible nodes to include in grep",
+	"Compatible nodes to exclude in grep",
+	"Diff: Mark matching nodes with +, others with -",
+	"Enter direct subnode names of matching nodes",
+	"Display offset",
+	"Node/property/compatible string to include in grep",
+	"Node/property/compatible string to exclude in grep",
+	"Output a header",
+	"Put \"/dts-v1/;\" on first line of dts output",
+	"Output a region list",
+	"List strings in string table",
+	"Include mem_rsvmap section in binary output",
+	"Node to include in grep",
+	"Node to exclude in grep",
+	"Property to include in grep",
+	"Property to exclude in grep",
+	"Remove unused strings from string table",
+	"Include root node and all properties",
+	"Show all subnodes matching nodes",
+	"Don't include supernodes of matching nodes",
+	"Include string table in binary output",
+	"Include matching aliases in output",
+	"-o <output file>",
+	"-O <output format>",
+	"Invert the sense of matching (select non-matching lines)",
+	USAGE_COMMON_OPTS_HELP
+};
+
+/**
+ * Call getopt_long() with standard options
+ *
+ * Since all util code runs getopt in the same way, provide a helper.
+ */
+#define util_getopt_long() getopt_long(argc, argv, usage_short_opts, \
+				       usage_long_opts, NULL)
+
+void util_usage(const char *errmsg, const char *synopsis,
+		const char *short_opts, struct option const long_opts[],
+		const char * const opts_help[])
+{
+	FILE *fp = errmsg ? stderr : stdout;
+	const char a_arg[] = "<arg>";
+	size_t a_arg_len = strlen(a_arg) + 1;
+	size_t i;
+	int optlen;
+
+	fprintf(fp,
+		"Usage: %s\n"
+		"\n"
+		"Options: -[%s]\n", synopsis, short_opts);
+
+	/* prescan the --long opt length to auto-align */
+	optlen = 0;
+	for (i = 0; long_opts[i].name; ++i) {
+		/* +1 is for space between --opt and help text */
+		int l = strlen(long_opts[i].name) + 1;
+		if (long_opts[i].has_arg == a_argument)
+			l += a_arg_len;
+		if (optlen < l)
+			optlen = l;
+	}
+
+	for (i = 0; long_opts[i].name; ++i) {
+		/* helps when adding new applets or options */
+		assert(opts_help[i] != NULL);
+
+		/* first output the short flag if it has one */
+		if (long_opts[i].val > '~')
+			fprintf(fp, "      ");
+		else
+			fprintf(fp, "  -%c, ", long_opts[i].val);
+
+		/* then the long flag */
+		if (long_opts[i].has_arg == no_argument) {
+			fprintf(fp, "--%-*s", optlen, long_opts[i].name);
+		} else {
+			fprintf(fp, "--%s %s%*s", long_opts[i].name, a_arg,
+				(int)(optlen - strlen(long_opts[i].name) -
+				a_arg_len), "");
+		}
+
+		/* finally the help text */
+		fprintf(fp, "%s\n", opts_help[i]);
+	}
+
+	if (errmsg) {
+		fprintf(fp, "\nError: %s\n", errmsg);
+		exit(EXIT_FAILURE);
+	} else {
+		exit(EXIT_SUCCESS);
+	}
+}
+
+/**
+ * Show usage and exit
+ *
+ * If you name all your usage variables with usage_xxx, then you can call this
+ * help macro rather than expanding all arguments yourself.
+ *
+ * @param errmsg	If non-NULL, an error message to display
+ */
+#define usage(errmsg) \
+	util_usage(errmsg, usage_synopsis, usage_short_opts, \
+		   usage_long_opts, usage_opts_help)
+
+void util_version(void)
+{
+	printf("Version: %s\n", "(U-Boot)");
+	exit(0);
+}
+
+static void scan_args(struct display_info *disp, int argc, char *argv[])
+{
+	int opt;
+
+	while ((opt = util_getopt_long()) != EOF) {
+		int type = 0;
+		int inc = 1;
+
+		switch (opt) {
+		case_USAGE_COMMON_FLAGS
+		case 'a':
+			disp->show_addr = 1;
+			break;
+		case 'A':
+			disp->all = 1;
+			break;
+		case 'b':
+			type = FDT_NODE_HAS_PROP;
+			break;
+		case 'C':
+			inc = 0;
+			/* no break */
+		case 'c':
+			type = FDT_IS_COMPAT;
+			break;
+		case 'd':
+			disp->diff = 1;
+			break;
+		case 'e':
+			disp->flags |= FDT_REG_DIRECT_SUBNODES;
+			break;
+		case 'f':
+			disp->show_offset = 1;
+			break;
+		case 'G':
+			inc = 0;
+			/* no break */
+		case 'g':
+			type = FDT_ANY_GLOBAL;
+			break;
+		case 'H':
+			disp->header = 1;
+			break;
+		case 'l':
+			disp->region_list = 1;
+			break;
+		case 'L':
+			disp->list_strings = 1;
+			break;
+		case 'm':
+			disp->flags |= FDT_REG_ADD_MEM_RSVMAP;
+			break;
+		case 'N':
+			inc = 0;
+			/* no break */
+		case 'n':
+			type = FDT_IS_NODE;
+			break;
+		case 'o':
+			disp->output_fname = optarg;
+			break;
+		case 'O':
+			if (!strcmp(optarg, "dtb"))
+				disp->output = OUT_DTB;
+			else if (!strcmp(optarg, "dts"))
+				disp->output = OUT_DTS;
+			else if (!strcmp(optarg, "bin"))
+				disp->output = OUT_BIN;
+			else
+				usage("Unknown output format");
+			break;
+		case 'P':
+			inc = 0;
+			/* no break */
+		case 'p':
+			type = FDT_IS_PROP;
+			break;
+		case 'r':
+			disp->remove_strings = 1;
+			break;
+		case 'R':
+			disp->include_root = 1;
+			break;
+		case 's':
+			disp->flags |= FDT_REG_ALL_SUBNODES;
+			break;
+		case 'S':
+			disp->flags &= ~FDT_REG_SUPERNODES;
+			break;
+		case 't':
+			disp->flags |= FDT_REG_ADD_STRING_TAB;
+			break;
+		case 'T':
+			disp->add_aliases = 1;
+			break;
+		case 'v':
+			disp->invert = 1;
+			break;
+		case 'I':
+			disp->show_dts_version = 1;
+			break;
+		}
+
+		if (type && value_add(disp, &disp->value_head, type, inc,
+				      optarg))
+			usage("Cannot add value");
+	}
+
+	if (disp->invert && disp->types_exc)
+		usage("-v has no meaning when used with 'exclude' conditions");
+}
+
+int main(int argc, char *argv[])
+{
+	char *filename = NULL;
+	struct display_info disp;
+	int ret;
+
+	/* set defaults */
+	memset(&disp, '\0', sizeof(disp));
+	disp.flags = FDT_REG_SUPERNODES;	/* Default flags */
+
+	scan_args(&disp, argc, argv);
+
+	/* Show matched lines in colour if we can */
+	disp.colour = disp.all && isatty(0);
+
+	/* Any additional arguments can match anything, just like -g */
+	while (optind < argc - 1) {
+		if (value_add(&disp, &disp.value_head, FDT_IS_ANY, 1,
+			      argv[optind++]))
+			usage("Cannot add value");
+	}
+
+	if (optind < argc)
+		filename = argv[optind++];
+	if (!filename)
+		usage("Missing filename");
+
+	/* If a valid .dtb is required, set flags to ensure we get one */
+	if (disp.output == OUT_DTB) {
+		disp.header = 1;
+		disp.flags |= FDT_REG_ADD_MEM_RSVMAP | FDT_REG_ADD_STRING_TAB;
+	}
+
+	if (disp.output_fname) {
+		disp.fout = fopen(disp.output_fname, "w");
+		if (!disp.fout)
+			usage("Cannot open output file");
+	} else {
+		disp.fout = stdout;
+	}
+
+	/* Run the grep and output the results */
+	ret = do_fdtgrep(&disp, filename);
+	if (disp.output_fname)
+		fclose(disp.fout);
+	if (ret)
+		return 1;
+
+	return 0;
+}