1 files changed, 926 insertions, 0 deletions

diff --git a/scripts/dtc/flattree.c b/scripts/dtc/flattree.c
new file mode 100644
index 0000000000..95e43d32c3
--- /dev/null
+++ b/scripts/dtc/flattree.c
@@ -0,0 +1,926 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * (C) Copyright David Gibson <dwg@au1.ibm.com>, IBM Corporation.  2005.
+ */
+
+#include "dtc.h"
+#include "srcpos.h"
+
+#define FTF_FULLPATH	0x1
+#define FTF_VARALIGN	0x2
+#define FTF_NAMEPROPS	0x4
+#define FTF_BOOTCPUID	0x8
+#define FTF_STRTABSIZE	0x10
+#define FTF_STRUCTSIZE	0x20
+#define FTF_NOPS	0x40
+
+static struct version_info {
+	int version;
+	int last_comp_version;
+	int hdr_size;
+	int flags;
+} version_table[] = {
+	{1, 1, FDT_V1_SIZE,
+	 FTF_FULLPATH|FTF_VARALIGN|FTF_NAMEPROPS},
+	{2, 1, FDT_V2_SIZE,
+	 FTF_FULLPATH|FTF_VARALIGN|FTF_NAMEPROPS|FTF_BOOTCPUID},
+	{3, 1, FDT_V3_SIZE,
+	 FTF_FULLPATH|FTF_VARALIGN|FTF_NAMEPROPS|FTF_BOOTCPUID|FTF_STRTABSIZE},
+	{16, 16, FDT_V3_SIZE,
+	 FTF_BOOTCPUID|FTF_STRTABSIZE|FTF_NOPS},
+	{17, 16, FDT_V17_SIZE,
+	 FTF_BOOTCPUID|FTF_STRTABSIZE|FTF_STRUCTSIZE|FTF_NOPS},
+};
+
+struct emitter {
+	void (*cell)(void *, cell_t);
+	void (*string)(void *, const char *, int);
+	void (*align)(void *, int);
+	void (*data)(void *, struct data);
+	void (*beginnode)(void *, struct label *labels);
+	void (*endnode)(void *, struct label *labels);
+	void (*property)(void *, struct label *labels);
+};
+
+static void bin_emit_cell(void *e, cell_t val)
+{
+	struct data *dtbuf = e;
+
+	*dtbuf = data_append_cell(*dtbuf, val);
+}
+
+static void bin_emit_string(void *e, const char *str, int len)
+{
+	struct data *dtbuf = e;
+
+	if (len == 0)
+		len = strlen(str);
+
+	*dtbuf = data_append_data(*dtbuf, str, len);
+	*dtbuf = data_append_byte(*dtbuf, '\0');
+}
+
+static void bin_emit_align(void *e, int a)
+{
+	struct data *dtbuf = e;
+
+	*dtbuf = data_append_align(*dtbuf, a);
+}
+
+static void bin_emit_data(void *e, struct data d)
+{
+	struct data *dtbuf = e;
+
+	*dtbuf = data_append_data(*dtbuf, d.val, d.len);
+}
+
+static void bin_emit_beginnode(void *e, struct label *labels)
+{
+	bin_emit_cell(e, FDT_BEGIN_NODE);
+}
+
+static void bin_emit_endnode(void *e, struct label *labels)
+{
+	bin_emit_cell(e, FDT_END_NODE);
+}
+
+static void bin_emit_property(void *e, struct label *labels)
+{
+	bin_emit_cell(e, FDT_PROP);
+}
+
+static struct emitter bin_emitter = {
+	.cell = bin_emit_cell,
+	.string = bin_emit_string,
+	.align = bin_emit_align,
+	.data = bin_emit_data,
+	.beginnode = bin_emit_beginnode,
+	.endnode = bin_emit_endnode,
+	.property = bin_emit_property,
+};
+
+static void emit_label(FILE *f, const char *prefix, const char *label)
+{
+	fprintf(f, "\t.globl\t%s_%s\n", prefix, label);
+	fprintf(f, "%s_%s:\n", prefix, label);
+	fprintf(f, "_%s_%s:\n", prefix, label);
+}
+
+static void emit_offset_label(FILE *f, const char *label, int offset)
+{
+	fprintf(f, "\t.globl\t%s\n", label);
+	fprintf(f, "%s\t= . + %d\n", label, offset);
+}
+
+#define ASM_EMIT_BELONG(f, fmt, ...) \
+	{ \
+		fprintf((f), "\t.byte\t((" fmt ") >> 24) & 0xff\n", __VA_ARGS__); \
+		fprintf((f), "\t.byte\t((" fmt ") >> 16) & 0xff\n", __VA_ARGS__); \
+		fprintf((f), "\t.byte\t((" fmt ") >> 8) & 0xff\n", __VA_ARGS__); \
+		fprintf((f), "\t.byte\t(" fmt ") & 0xff\n", __VA_ARGS__); \
+	}
+
+static void asm_emit_cell(void *e, cell_t val)
+{
+	FILE *f = e;
+
+	fprintf(f, "\t.byte\t0x%02x\n" "\t.byte\t0x%02x\n"
+		"\t.byte\t0x%02x\n" "\t.byte\t0x%02x\n",
+		(val >> 24) & 0xff, (val >> 16) & 0xff,
+		(val >> 8) & 0xff, val & 0xff);
+}
+
+static void asm_emit_string(void *e, const char *str, int len)
+{
+	FILE *f = e;
+
+	if (len != 0)
+		fprintf(f, "\t.asciz\t\"%.*s\"\n", len, str);
+	else
+		fprintf(f, "\t.asciz\t\"%s\"\n", str);
+}
+
+static void asm_emit_align(void *e, int a)
+{
+	FILE *f = e;
+
+	fprintf(f, "\t.balign\t%d, 0\n", a);
+}
+
+static void asm_emit_data(void *e, struct data d)
+{
+	FILE *f = e;
+	unsigned int off = 0;
+	struct marker *m = d.markers;
+
+	for_each_marker_of_type(m, LABEL)
+		emit_offset_label(f, m->ref, m->offset);
+
+	while ((d.len - off) >= sizeof(uint32_t)) {
+		asm_emit_cell(e, dtb_ld32(d.val + off));
+		off += sizeof(uint32_t);
+	}
+
+	while ((d.len - off) >= 1) {
+		fprintf(f, "\t.byte\t0x%hhx\n", d.val[off]);
+		off += 1;
+	}
+
+	assert(off == d.len);
+}
+
+static void asm_emit_beginnode(void *e, struct label *labels)
+{
+	FILE *f = e;
+	struct label *l;
+
+	for_each_label(labels, l) {
+		fprintf(f, "\t.globl\t%s\n", l->label);
+		fprintf(f, "%s:\n", l->label);
+	}
+	fprintf(f, "\t/* FDT_BEGIN_NODE */\n");
+	asm_emit_cell(e, FDT_BEGIN_NODE);
+}
+
+static void asm_emit_endnode(void *e, struct label *labels)
+{
+	FILE *f = e;
+	struct label *l;
+
+	fprintf(f, "\t/* FDT_END_NODE */\n");
+	asm_emit_cell(e, FDT_END_NODE);
+	for_each_label(labels, l) {
+		fprintf(f, "\t.globl\t%s_end\n", l->label);
+		fprintf(f, "%s_end:\n", l->label);
+	}
+}
+
+static void asm_emit_property(void *e, struct label *labels)
+{
+	FILE *f = e;
+	struct label *l;
+
+	for_each_label(labels, l) {
+		fprintf(f, "\t.globl\t%s\n", l->label);
+		fprintf(f, "%s:\n", l->label);
+	}
+	fprintf(f, "\t/* FDT_PROP */\n");
+	asm_emit_cell(e, FDT_PROP);
+}
+
+static struct emitter asm_emitter = {
+	.cell = asm_emit_cell,
+	.string = asm_emit_string,
+	.align = asm_emit_align,
+	.data = asm_emit_data,
+	.beginnode = asm_emit_beginnode,
+	.endnode = asm_emit_endnode,
+	.property = asm_emit_property,
+};
+
+static int stringtable_insert(struct data *d, const char *str)
+{
+	unsigned int i;
+
+	/* FIXME: do this more efficiently? */
+
+	for (i = 0; i < d->len; i++) {
+		if (streq(str, d->val + i))
+			return i;
+	}
+
+	*d = data_append_data(*d, str, strlen(str)+1);
+	return i;
+}
+
+static void flatten_tree(struct node *tree, struct emitter *emit,
+			 void *etarget, struct data *strbuf,
+			 struct version_info *vi)
+{
+	struct property *prop;
+	struct node *child;
+	bool seen_name_prop = false;
+
+	if (tree->deleted)
+		return;
+
+	emit->beginnode(etarget, tree->labels);
+
+	if (vi->flags & FTF_FULLPATH)
+		emit->string(etarget, tree->fullpath, 0);
+	else
+		emit->string(etarget, tree->name, 0);
+
+	emit->align(etarget, sizeof(cell_t));
+
+	for_each_property(tree, prop) {
+		int nameoff;
+
+		if (streq(prop->name, "name"))
+			seen_name_prop = true;
+
+		nameoff = stringtable_insert(strbuf, prop->name);
+
+		emit->property(etarget, prop->labels);
+		emit->cell(etarget, prop->val.len);
+		emit->cell(etarget, nameoff);
+
+		if ((vi->flags & FTF_VARALIGN) && (prop->val.len >= 8))
+			emit->align(etarget, 8);
+
+		emit->data(etarget, prop->val);
+		emit->align(etarget, sizeof(cell_t));
+	}
+
+	if ((vi->flags & FTF_NAMEPROPS) && !seen_name_prop) {
+		emit->property(etarget, NULL);
+		emit->cell(etarget, tree->basenamelen+1);
+		emit->cell(etarget, stringtable_insert(strbuf, "name"));
+
+		if ((vi->flags & FTF_VARALIGN) && ((tree->basenamelen+1) >= 8))
+			emit->align(etarget, 8);
+
+		emit->string(etarget, tree->name, tree->basenamelen);
+		emit->align(etarget, sizeof(cell_t));
+	}
+
+	for_each_child(tree, child) {
+		flatten_tree(child, emit, etarget, strbuf, vi);
+	}
+
+	emit->endnode(etarget, tree->labels);
+}
+
+static struct data flatten_reserve_list(struct reserve_info *reservelist,
+				 struct version_info *vi)
+{
+	struct reserve_info *re;
+	struct data d = empty_data;
+	unsigned int j;
+
+	for (re = reservelist; re; re = re->next) {
+		d = data_append_re(d, re->address, re->size);
+	}
+	/*
+	 * Add additional reserved slots if the user asked for them.
+	 */
+	for (j = 0; j < reservenum; j++) {
+		d = data_append_re(d, 0, 0);
+	}
+
+	return d;
+}
+
+static void make_fdt_header(struct fdt_header *fdt,
+			    struct version_info *vi,
+			    int reservesize, int dtsize, int strsize,
+			    int boot_cpuid_phys)
+{
+	int reserve_off;
+
+	reservesize += sizeof(struct fdt_reserve_entry);
+
+	memset(fdt, 0xff, sizeof(*fdt));
+
+	fdt->magic = cpu_to_fdt32(FDT_MAGIC);
+	fdt->version = cpu_to_fdt32(vi->version);
+	fdt->last_comp_version = cpu_to_fdt32(vi->last_comp_version);
+
+	/* Reserve map should be doubleword aligned */
+	reserve_off = ALIGN(vi->hdr_size, 8);
+
+	fdt->off_mem_rsvmap = cpu_to_fdt32(reserve_off);
+	fdt->off_dt_struct = cpu_to_fdt32(reserve_off + reservesize);
+	fdt->off_dt_strings = cpu_to_fdt32(reserve_off + reservesize
+					  + dtsize);
+	fdt->totalsize = cpu_to_fdt32(reserve_off + reservesize + dtsize + strsize);
+
+	if (vi->flags & FTF_BOOTCPUID)
+		fdt->boot_cpuid_phys = cpu_to_fdt32(boot_cpuid_phys);
+	if (vi->flags & FTF_STRTABSIZE)
+		fdt->size_dt_strings = cpu_to_fdt32(strsize);
+	if (vi->flags & FTF_STRUCTSIZE)
+		fdt->size_dt_struct = cpu_to_fdt32(dtsize);
+}
+
+void dt_to_blob(FILE *f, struct dt_info *dti, int version)
+{
+	struct version_info *vi = NULL;
+	unsigned int i;
+	struct data blob       = empty_data;
+	struct data reservebuf = empty_data;
+	struct data dtbuf      = empty_data;
+	struct data strbuf     = empty_data;
+	struct fdt_header fdt;
+	int padlen = 0;
+
+	for (i = 0; i < ARRAY_SIZE(version_table); i++) {
+		if (version_table[i].version == version)
+			vi = &version_table[i];
+	}
+	if (!vi)
+		die("Unknown device tree blob version %d\n", version);
+
+	flatten_tree(dti->dt, &bin_emitter, &dtbuf, &strbuf, vi);
+	bin_emit_cell(&dtbuf, FDT_END);
+
+	reservebuf = flatten_reserve_list(dti->reservelist, vi);
+
+	/* Make header */
+	make_fdt_header(&fdt, vi, reservebuf.len, dtbuf.len, strbuf.len,
+			dti->boot_cpuid_phys);
+
+	/*
+	 * If the user asked for more space than is used, adjust the totalsize.
+	 */
+	if (minsize > 0) {
+		padlen = minsize - fdt32_to_cpu(fdt.totalsize);
+		if (padlen < 0) {
+			padlen = 0;
+			if (quiet < 1)
+				fprintf(stderr,
+					"Warning: blob size %"PRIu32" >= minimum size %d\n",
+					fdt32_to_cpu(fdt.totalsize), minsize);
+		}
+	}
+
+	if (padsize > 0)
+		padlen = padsize;
+
+	if (alignsize > 0)
+		padlen = ALIGN(fdt32_to_cpu(fdt.totalsize) + padlen, alignsize)
+			- fdt32_to_cpu(fdt.totalsize);
+
+	if (padlen > 0) {
+		int tsize = fdt32_to_cpu(fdt.totalsize);
+		tsize += padlen;
+		fdt.totalsize = cpu_to_fdt32(tsize);
+	}
+
+	/*
+	 * Assemble the blob: start with the header, add with alignment
+	 * the reserve buffer, add the reserve map terminating zeroes,
+	 * the device tree itself, and finally the strings.
+	 */
+	blob = data_append_data(blob, &fdt, vi->hdr_size);
+	blob = data_append_align(blob, 8);
+	blob = data_merge(blob, reservebuf);
+	blob = data_append_zeroes(blob, sizeof(struct fdt_reserve_entry));
+	blob = data_merge(blob, dtbuf);
+	blob = data_merge(blob, strbuf);
+
+	/*
+	 * If the user asked for more space than is used, pad out the blob.
+	 */
+	if (padlen > 0)
+		blob = data_append_zeroes(blob, padlen);
+
+	if (fwrite(blob.val, blob.len, 1, f) != 1) {
+		if (ferror(f))
+			die("Error writing device tree blob: %s\n",
+			    strerror(errno));
+		else
+			die("Short write on device tree blob\n");
+	}
+
+	/*
+	 * data_merge() frees the right-hand element so only the blob
+	 * remains to be freed.
+	 */
+	data_free(blob);
+}
+
+static void dump_stringtable_asm(FILE *f, struct data strbuf)
+{
+	const char *p;
+	int len;
+
+	p = strbuf.val;
+
+	while (p < (strbuf.val + strbuf.len)) {
+		len = strlen(p);
+		fprintf(f, "\t.asciz \"%s\"\n", p);
+		p += len+1;
+	}
+}
+
+void dt_to_asm(FILE *f, struct dt_info *dti, int version)
+{
+	struct version_info *vi = NULL;
+	unsigned int i;
+	struct data strbuf = empty_data;
+	struct reserve_info *re;
+	const char *symprefix = "dt";
+
+	for (i = 0; i < ARRAY_SIZE(version_table); i++) {
+		if (version_table[i].version == version)
+			vi = &version_table[i];
+	}
+	if (!vi)
+		die("Unknown device tree blob version %d\n", version);
+
+	fprintf(f, "/* autogenerated by dtc, do not edit */\n\n");
+
+	emit_label(f, symprefix, "blob_start");
+	emit_label(f, symprefix, "header");
+	fprintf(f, "\t/* magic */\n");
+	asm_emit_cell(f, FDT_MAGIC);
+	fprintf(f, "\t/* totalsize */\n");
+	ASM_EMIT_BELONG(f, "_%s_blob_abs_end - _%s_blob_start",
+			symprefix, symprefix);
+	fprintf(f, "\t/* off_dt_struct */\n");
+	ASM_EMIT_BELONG(f, "_%s_struct_start - _%s_blob_start",
+		symprefix, symprefix);
+	fprintf(f, "\t/* off_dt_strings */\n");
+	ASM_EMIT_BELONG(f, "_%s_strings_start - _%s_blob_start",
+		symprefix, symprefix);
+	fprintf(f, "\t/* off_mem_rsvmap */\n");
+	ASM_EMIT_BELONG(f, "_%s_reserve_map - _%s_blob_start",
+		symprefix, symprefix);
+	fprintf(f, "\t/* version */\n");
+	asm_emit_cell(f, vi->version);
+	fprintf(f, "\t/* last_comp_version */\n");
+	asm_emit_cell(f, vi->last_comp_version);
+
+	if (vi->flags & FTF_BOOTCPUID) {
+		fprintf(f, "\t/* boot_cpuid_phys */\n");
+		asm_emit_cell(f, dti->boot_cpuid_phys);
+	}
+
+	if (vi->flags & FTF_STRTABSIZE) {
+		fprintf(f, "\t/* size_dt_strings */\n");
+		ASM_EMIT_BELONG(f, "_%s_strings_end - _%s_strings_start",
+				symprefix, symprefix);
+	}
+
+	if (vi->flags & FTF_STRUCTSIZE) {
+		fprintf(f, "\t/* size_dt_struct */\n");
+		ASM_EMIT_BELONG(f, "_%s_struct_end - _%s_struct_start",
+			symprefix, symprefix);
+	}
+
+	/*
+	 * Reserve map entries.
+	 * Align the reserve map to a doubleword boundary.
+	 * Each entry is an (address, size) pair of u64 values.
+	 * Always supply a zero-sized temination entry.
+	 */
+	asm_emit_align(f, 8);
+	emit_label(f, symprefix, "reserve_map");
+
+	fprintf(f, "/* Memory reserve map from source file */\n");
+
+	/*
+	 * Use .long on high and low halves of u64s to avoid .quad
+	 * as it appears .quad isn't available in some assemblers.
+	 */
+	for (re = dti->reservelist; re; re = re->next) {
+		struct label *l;
+
+		for_each_label(re->labels, l) {
+			fprintf(f, "\t.globl\t%s\n", l->label);
+			fprintf(f, "%s:\n", l->label);
+		}
+		ASM_EMIT_BELONG(f, "0x%08x", (unsigned int)(re->address >> 32));
+		ASM_EMIT_BELONG(f, "0x%08x",
+				(unsigned int)(re->address & 0xffffffff));
+		ASM_EMIT_BELONG(f, "0x%08x", (unsigned int)(re->size >> 32));
+		ASM_EMIT_BELONG(f, "0x%08x", (unsigned int)(re->size & 0xffffffff));
+	}
+	for (i = 0; i < reservenum; i++) {
+		fprintf(f, "\t.long\t0, 0\n\t.long\t0, 0\n");
+	}
+
+	fprintf(f, "\t.long\t0, 0\n\t.long\t0, 0\n");
+
+	emit_label(f, symprefix, "struct_start");
+	flatten_tree(dti->dt, &asm_emitter, f, &strbuf, vi);
+
+	fprintf(f, "\t/* FDT_END */\n");
+	asm_emit_cell(f, FDT_END);
+	emit_label(f, symprefix, "struct_end");
+
+	emit_label(f, symprefix, "strings_start");
+	dump_stringtable_asm(f, strbuf);
+	emit_label(f, symprefix, "strings_end");
+
+	emit_label(f, symprefix, "blob_end");
+
+	/*
+	 * If the user asked for more space than is used, pad it out.
+	 */
+	if (minsize > 0) {
+		fprintf(f, "\t.space\t%d - (_%s_blob_end - _%s_blob_start), 0\n",
+			minsize, symprefix, symprefix);
+	}
+	if (padsize > 0) {
+		fprintf(f, "\t.space\t%d, 0\n", padsize);
+	}
+	if (alignsize > 0)
+		asm_emit_align(f, alignsize);
+	emit_label(f, symprefix, "blob_abs_end");
+
+	data_free(strbuf);
+}
+
+struct inbuf {
+	char *base, *limit, *ptr;
+};
+
+static void inbuf_init(struct inbuf *inb, void *base, void *limit)
+{
+	inb->base = base;
+	inb->limit = limit;
+	inb->ptr = inb->base;
+}
+
+static void flat_read_chunk(struct inbuf *inb, void *p, int len)
+{
+	if ((inb->ptr + len) > inb->limit)
+		die("Premature end of data parsing flat device tree\n");
+
+	memcpy(p, inb->ptr, len);
+
+	inb->ptr += len;
+}
+
+static uint32_t flat_read_word(struct inbuf *inb)
+{
+	fdt32_t val;
+
+	assert(((inb->ptr - inb->base) % sizeof(val)) == 0);
+
+	flat_read_chunk(inb, &val, sizeof(val));
+
+	return fdt32_to_cpu(val);
+}
+
+static void flat_realign(struct inbuf *inb, int align)
+{
+	int off = inb->ptr - inb->base;
+
+	inb->ptr = inb->base + ALIGN(off, align);
+	if (inb->ptr > inb->limit)
+		die("Premature end of data parsing flat device tree\n");
+}
+
+static char *flat_read_string(struct inbuf *inb)
+{
+	int len = 0;
+	const char *p = inb->ptr;
+	char *str;
+
+	do {
+		if (p >= inb->limit)
+			die("Premature end of data parsing flat device tree\n");
+		len++;
+	} while ((*p++) != '\0');
+
+	str = xstrdup(inb->ptr);
+
+	inb->ptr += len;
+
+	flat_realign(inb, sizeof(uint32_t));
+
+	return str;
+}
+
+static struct data flat_read_data(struct inbuf *inb, int len)
+{
+	struct data d = empty_data;
+
+	if (len == 0)
+		return empty_data;
+
+	d = data_grow_for(d, len);
+	d.len = len;
+
+	flat_read_chunk(inb, d.val, len);
+
+	flat_realign(inb, sizeof(uint32_t));
+
+	return d;
+}
+
+static char *flat_read_stringtable(struct inbuf *inb, int offset)
+{
+	const char *p;
+
+	p = inb->base + offset;
+	while (1) {
+		if (p >= inb->limit || p < inb->base)
+			die("String offset %d overruns string table\n",
+			    offset);
+
+		if (*p == '\0')
+			break;
+
+		p++;
+	}
+
+	return xstrdup(inb->base + offset);
+}
+
+static struct property *flat_read_property(struct inbuf *dtbuf,
+					   struct inbuf *strbuf, int flags)
+{
+	uint32_t proplen, stroff;
+	char *name;
+	struct data val;
+
+	proplen = flat_read_word(dtbuf);
+	stroff = flat_read_word(dtbuf);
+
+	name = flat_read_stringtable(strbuf, stroff);
+
+	if ((flags & FTF_VARALIGN) && (proplen >= 8))
+		flat_realign(dtbuf, 8);
+
+	val = flat_read_data(dtbuf, proplen);
+
+	return build_property(name, val, NULL);
+}
+
+
+static struct reserve_info *flat_read_mem_reserve(struct inbuf *inb)
+{
+	struct reserve_info *reservelist = NULL;
+	struct reserve_info *new;
+	struct fdt_reserve_entry re;
+
+	/*
+	 * Each entry is a pair of u64 (addr, size) values for 4 cell_t's.
+	 * List terminates at an entry with size equal to zero.
+	 *
+	 * First pass, count entries.
+	 */
+	while (1) {
+		uint64_t address, size;
+
+		flat_read_chunk(inb, &re, sizeof(re));
+		address  = fdt64_to_cpu(re.address);
+		size = fdt64_to_cpu(re.size);
+		if (size == 0)
+			break;
+
+		new = build_reserve_entry(address, size);
+		reservelist = add_reserve_entry(reservelist, new);
+	}
+
+	return reservelist;
+}
+
+
+static char *nodename_from_path(const char *ppath, const char *cpath)
+{
+	int plen;
+
+	plen = strlen(ppath);
+
+	if (!strstarts(cpath, ppath))
+		die("Path \"%s\" is not valid as a child of \"%s\"\n",
+		    cpath, ppath);
+
+	/* root node is a special case */
+	if (!streq(ppath, "/"))
+		plen++;
+
+	return xstrdup(cpath + plen);
+}
+
+static struct node *unflatten_tree(struct inbuf *dtbuf,
+				   struct inbuf *strbuf,
+				   const char *parent_flatname, int flags)
+{
+	struct node *node;
+	char *flatname;
+	uint32_t val;
+
+	node = build_node(NULL, NULL, NULL);
+
+	flatname = flat_read_string(dtbuf);
+
+	if (flags & FTF_FULLPATH)
+		node->name = nodename_from_path(parent_flatname, flatname);
+	else
+		node->name = flatname;
+
+	do {
+		struct property *prop;
+		struct node *child;
+
+		val = flat_read_word(dtbuf);
+		switch (val) {
+		case FDT_PROP:
+			if (node->children)
+				fprintf(stderr, "Warning: Flat tree input has "
+					"subnodes preceding a property.\n");
+			prop = flat_read_property(dtbuf, strbuf, flags);
+			add_property(node, prop);
+			break;
+
+		case FDT_BEGIN_NODE:
+			child = unflatten_tree(dtbuf,strbuf, flatname, flags);
+			add_child(node, child);
+			break;
+
+		case FDT_END_NODE:
+			break;
+
+		case FDT_END:
+			die("Premature FDT_END in device tree blob\n");
+			break;
+
+		case FDT_NOP:
+			if (!(flags & FTF_NOPS))
+				fprintf(stderr, "Warning: NOP tag found in flat tree"
+					" version <16\n");
+
+			/* Ignore */
+			break;
+
+		default:
+			die("Invalid opcode word %08x in device tree blob\n",
+			    val);
+		}
+	} while (val != FDT_END_NODE);
+
+	if (node->name != flatname) {
+		free(flatname);
+	}
+
+	return node;
+}
+
+
+struct dt_info *dt_from_blob(const char *fname)
+{
+	FILE *f;
+	fdt32_t magic_buf, totalsize_buf;
+	uint32_t magic, totalsize, version, size_dt, boot_cpuid_phys;
+	uint32_t off_dt, off_str, off_mem_rsvmap;
+	int rc;
+	char *blob;
+	struct fdt_header *fdt;
+	char *p;
+	struct inbuf dtbuf, strbuf;
+	struct inbuf memresvbuf;
+	int sizeleft;
+	struct reserve_info *reservelist;
+	struct node *tree;
+	uint32_t val;
+	int flags = 0;
+
+	f = srcfile_relative_open(fname, NULL);
+
+	rc = fread(&magic_buf, sizeof(magic_buf), 1, f);
+	if (ferror(f))
+		die("Error reading DT blob magic number: %s\n",
+		    strerror(errno));
+	if (rc < 1) {
+		if (feof(f))
+			die("EOF reading DT blob magic number\n");
+		else
+			die("Mysterious short read reading magic number\n");
+	}
+
+	magic = fdt32_to_cpu(magic_buf);
+	if (magic != FDT_MAGIC)
+		die("Blob has incorrect magic number\n");
+
+	rc = fread(&totalsize_buf, sizeof(totalsize_buf), 1, f);
+	if (ferror(f))
+		die("Error reading DT blob size: %s\n", strerror(errno));
+	if (rc < 1) {
+		if (feof(f))
+			die("EOF reading DT blob size\n");
+		else
+			die("Mysterious short read reading blob size\n");
+	}
+
+	totalsize = fdt32_to_cpu(totalsize_buf);
+	if (totalsize < FDT_V1_SIZE)
+		die("DT blob size (%d) is too small\n", totalsize);
+
+	blob = xmalloc(totalsize);
+
+	fdt = (struct fdt_header *)blob;
+	fdt->magic = cpu_to_fdt32(magic);
+	fdt->totalsize = cpu_to_fdt32(totalsize);
+
+	sizeleft = totalsize - sizeof(magic) - sizeof(totalsize);
+	p = blob + sizeof(magic)  + sizeof(totalsize);
+
+	while (sizeleft) {
+		if (feof(f))
+			die("EOF before reading %d bytes of DT blob\n",
+			    totalsize);
+
+		rc = fread(p, 1, sizeleft, f);
+		if (ferror(f))
+			die("Error reading DT blob: %s\n",
+			    strerror(errno));
+
+		sizeleft -= rc;
+		p += rc;
+	}
+
+	off_dt = fdt32_to_cpu(fdt->off_dt_struct);
+	off_str = fdt32_to_cpu(fdt->off_dt_strings);
+	off_mem_rsvmap = fdt32_to_cpu(fdt->off_mem_rsvmap);
+	version = fdt32_to_cpu(fdt->version);
+	boot_cpuid_phys = fdt32_to_cpu(fdt->boot_cpuid_phys);
+
+	if (off_mem_rsvmap >= totalsize)
+		die("Mem Reserve structure offset exceeds total size\n");
+
+	if (off_dt >= totalsize)
+		die("DT structure offset exceeds total size\n");
+
+	if (off_str > totalsize)
+		die("String table offset exceeds total size\n");
+
+	if (version >= 3) {
+		uint32_t size_str = fdt32_to_cpu(fdt->size_dt_strings);
+		if ((off_str+size_str < off_str) || (off_str+size_str > totalsize))
+			die("String table extends past total size\n");
+		inbuf_init(&strbuf, blob + off_str, blob + off_str + size_str);
+	} else {
+		inbuf_init(&strbuf, blob + off_str, blob + totalsize);
+	}
+
+	if (version >= 17) {
+		size_dt = fdt32_to_cpu(fdt->size_dt_struct);
+		if ((off_dt+size_dt < off_dt) || (off_dt+size_dt > totalsize))
+			die("Structure block extends past total size\n");
+	}
+
+	if (version < 16) {
+		flags |= FTF_FULLPATH | FTF_NAMEPROPS | FTF_VARALIGN;
+	} else {
+		flags |= FTF_NOPS;
+	}
+
+	inbuf_init(&memresvbuf,
+		   blob + off_mem_rsvmap, blob + totalsize);
+	inbuf_init(&dtbuf, blob + off_dt, blob + totalsize);
+
+	reservelist = flat_read_mem_reserve(&memresvbuf);
+
+	val = flat_read_word(&dtbuf);
+
+	if (val != FDT_BEGIN_NODE)
+		die("Device tree blob doesn't begin with FDT_BEGIN_NODE (begins with 0x%08x)\n", val);
+
+	tree = unflatten_tree(&dtbuf, &strbuf, "", flags);
+
+	val = flat_read_word(&dtbuf);
+	if (val != FDT_END)
+		die("Device tree blob doesn't end with FDT_END\n");
+
+	free(blob);
+
+	fclose(f);
+
+	return build_dt_info(DTSF_V1, reservelist, tree, boot_cpuid_phys);
+}