/*
   * (C) Copyright David Gibson <dwg@au1.ibm.com>, IBM Corporation.  2005.
   *
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License as
   * published by the Free Software Foundation; either version 2 of the
   * License, or (at your option) any later version.
   *
   *  This program is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   *  General Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License
   *  along with this program; if not, write to the Free Software
   *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
   *                                                                   USA
   */
  
  #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 *, 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, 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
  ", prefix, label);
  	fprintf(f, "%s_%s:
  ", prefix, label);
  	fprintf(f, "_%s_%s:
  ", prefix, label);
  }
  
  static void emit_offset_label(FILE *f, const char *label, int offset)
  {
  	fprintf(f, "\t.globl\t%s
  ", label);
  	fprintf(f, "%s\t= . + %d
  ", label, offset);
  }

  #define ASM_EMIT_BELONG(f, fmt, ...) \
  	{ \
  		fprintf((f), "\t.byte\t((" fmt ") >> 24) & 0xff
  ", __VA_ARGS__); \
  		fprintf((f), "\t.byte\t((" fmt ") >> 16) & 0xff
  ", __VA_ARGS__); \
  		fprintf((f), "\t.byte\t((" fmt ") >> 8) & 0xff
  ", __VA_ARGS__); \
  		fprintf((f), "\t.byte\t(" fmt ") & 0xff
  ", __VA_ARGS__); \
  	}

  static void asm_emit_cell(void *e, cell_t val)
  {
  	FILE *f = e;

  	fprintf(f, "\t.byte 0x%02x; .byte 0x%02x; .byte 0x%02x; .byte 0x%02x
  ",
  		(val >> 24) & 0xff, (val >> 16) & 0xff,
  		(val >> 8) & 0xff, val & 0xff);

  }
  
  static void asm_emit_string(void *e, char *str, int len)
  {
  	FILE *f = e;
  	char c = 0;
  
  	if (len != 0) {
  		/* XXX: ewww */
  		c = str[len];
  		str[len] = '\0';
  	}
  
  	fprintf(f, "\t.string\t\"%s\"
  ", str);
  
  	if (len != 0) {
  		str[len] = c;
  	}
  }
  
  static void asm_emit_align(void *e, int a)
  {
  	FILE *f = e;

  	fprintf(f, "\t.balign\t%d, 0
  ", a);

  }
  
  static void asm_emit_data(void *e, struct data d)
  {
  	FILE *f = e;
  	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, fdt32_to_cpu(*((uint32_t *)(d.val+off))));

  		off += sizeof(uint32_t);

  	}

  	while ((d.len - off) >= 1) {

  		fprintf(f, "\t.byte\t0x%hhx
  ", 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
  ", l->label);
  		fprintf(f, "%s:
  ", l->label);

  	}

  	fprintf(f, "\t/* FDT_BEGIN_NODE */
  ");
  	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 */
  ");
  	asm_emit_cell(e, FDT_END_NODE);
  	for_each_label(labels, l) {
  		fprintf(f, "\t.globl\t%s_end
  ", l->label);
  		fprintf(f, "%s_end:
  ", 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
  ", l->label);
  		fprintf(f, "%s:
  ", l->label);

  	}

  	fprintf(f, "\t/* FDT_PROP */
  ");
  	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)
  {
  	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;
  	int seen_name_prop = 0;

  	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 = 1;
  
  		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;
  	static struct fdt_reserve_entry null_re = {0,0};
  	int    j;
  
  	for (re = reservelist; re; re = re->next) {
  		d = data_append_re(d, &re->re);
  	}
  	/*
  	 * Add additional reserved slots if the user asked for them.
  	 */
  	for (j = 0; j < reservenum; j++) {
  		d = data_append_re(d, &null_re);
  	}
  
  	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 boot_info *bi, int version)

  {
  	struct version_info *vi = NULL;
  	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
  ", version);
  
  	flatten_tree(bi->dt, &bin_emitter, &dtbuf, &strbuf, vi);
  	bin_emit_cell(&dtbuf, FDT_END);
  
  	reservebuf = flatten_reserve_list(bi->reservelist, vi);
  
  	/* Make header */
  	make_fdt_header(&fdt, vi, reservebuf.len, dtbuf.len, strbuf.len,

  			bi->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) && (quiet < 1))
  			fprintf(stderr,
  				"Warning: blob size %d >= minimum size %d
  ",

  				fdt32_to_cpu(fdt.totalsize), minsize);

  	}
  
  	if (padsize > 0)
  		padlen = padsize;
  
  	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
  ",
  			    strerror(errno));
  		else
  			die("Short write on device tree blob
  ");
  	}

  
  	/*
  	 * 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.string \"%s\"
  ", p);
  		p += len+1;
  	}
  }

  void dt_to_asm(FILE *f, struct boot_info *bi, int version)

  {
  	struct version_info *vi = NULL;
  	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
  ", version);
  
  	fprintf(f, "/* autogenerated by dtc, do not edit */
  
  ");

  
  	emit_label(f, symprefix, "blob_start");
  	emit_label(f, symprefix, "header");

  	fprintf(f, "\t/* magic */
  ");
  	asm_emit_cell(f, FDT_MAGIC);
  	fprintf(f, "\t/* totalsize */
  ");
  	ASM_EMIT_BELONG(f, "_%s_blob_abs_end - _%s_blob_start",
  			symprefix, symprefix);
  	fprintf(f, "\t/* off_dt_struct */
  ");
  	ASM_EMIT_BELONG(f, "_%s_struct_start - _%s_blob_start",

  		symprefix, symprefix);

  	fprintf(f, "\t/* off_dt_strings */
  ");
  	ASM_EMIT_BELONG(f, "_%s_strings_start - _%s_blob_start",

  		symprefix, symprefix);

  	fprintf(f, "\t/* off_mem_rsvmap */
  ");
  	ASM_EMIT_BELONG(f, "_%s_reserve_map - _%s_blob_start",

  		symprefix, symprefix);

  	fprintf(f, "\t/* version */
  ");
  	asm_emit_cell(f, vi->version);
  	fprintf(f, "\t/* last_comp_version */
  ");
  	asm_emit_cell(f, vi->last_comp_version);
  
  	if (vi->flags & FTF_BOOTCPUID) {
  		fprintf(f, "\t/* boot_cpuid_phys */
  ");
  		asm_emit_cell(f, bi->boot_cpuid_phys);
  	}

  	if (vi->flags & FTF_STRTABSIZE) {
  		fprintf(f, "\t/* size_dt_strings */
  ");
  		ASM_EMIT_BELONG(f, "_%s_strings_end - _%s_strings_start",
  				symprefix, symprefix);
  	}

  	if (vi->flags & FTF_STRUCTSIZE) {
  		fprintf(f, "\t/* size_dt_struct */
  ");
  		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 */
  ");
  
  	/*
  	 * Use .long on high and low halfs of u64s to avoid .quad
  	 * as it appears .quad isn't available in some assemblers.
  	 */
  	for (re = bi->reservelist; re; re = re->next) {

  		struct label *l;
  
  		for_each_label(re->labels, l) {
  			fprintf(f, "\t.globl\t%s
  ", l->label);
  			fprintf(f, "%s:
  ", l->label);

  		}

  		ASM_EMIT_BELONG(f, "0x%08x", (unsigned int)(re->re.address >> 32));
  		ASM_EMIT_BELONG(f, "0x%08x",
  				(unsigned int)(re->re.address & 0xffffffff));
  		ASM_EMIT_BELONG(f, "0x%08x", (unsigned int)(re->re.size >> 32));
  		ASM_EMIT_BELONG(f, "0x%08x", (unsigned int)(re->re.size & 0xffffffff));

  	}
  	for (i = 0; i < reservenum; i++) {
  		fprintf(f, "\t.long\t0, 0
  \t.long\t0, 0
  ");
  	}
  
  	fprintf(f, "\t.long\t0, 0
  \t.long\t0, 0
  ");
  
  	emit_label(f, symprefix, "struct_start");
  	flatten_tree(bi->dt, &asm_emitter, f, &strbuf, vi);

  
  	fprintf(f, "\t/* FDT_END */
  ");
  	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
  ",
  			minsize, symprefix, symprefix);
  	}
  	if (padsize > 0) {
  		fprintf(f, "\t.space\t%d, 0
  ", padsize);
  	}
  	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
  ");
  
  	memcpy(p, inb->ptr, len);
  
  	inb->ptr += len;
  }

  static uint32_t flat_read_word(struct inbuf *inb)

  {

  	uint32_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
  ");
  }
  
  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
  ");
  		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
  ",
  			    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);

  }
  
  
  static struct reserve_info *flat_read_mem_reserve(struct inbuf *inb)
  {
  	struct reserve_info *reservelist = NULL;
  	struct reserve_info *new;
  	const char *p;
  	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.
  	 */
  	p = inb->ptr;
  	while (1) {
  		flat_read_chunk(inb, &re, sizeof(re));

  		re.address  = fdt64_to_cpu(re.address);
  		re.size = fdt64_to_cpu(re.size);

  		if (re.size == 0)
  			break;

  		new = build_reserve_entry(re.address, re.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 (!strneq(ppath, cpath, plen))
  		die("Path \"%s\" is not valid as a child of \"%s\"
  ",
  		    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);

  	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.
  ");
  			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
  ");
  			break;
  
  		case FDT_NOP:
  			if (!(flags & FTF_NOPS))
  				fprintf(stderr, "Warning: NOP tag found in flat tree"
  					" version <16
  ");
  
  			/* Ignore */
  			break;
  
  		default:
  			die("Invalid opcode word %08x in device tree blob
  ",
  			    val);
  		}
  	} while (val != FDT_END_NODE);
  
  	return node;
  }

  struct boot_info *dt_from_blob(const char *fname)

  {

  	FILE *f;

  	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, sizeof(magic), 1, f);
  	if (ferror(f))

  		die("Error reading DT blob magic number: %s
  ",
  		    strerror(errno));
  	if (rc < 1) {

  		if (feof(f))

  			die("EOF reading DT blob magic number
  ");
  		else
  			die("Mysterious short read reading magic number
  ");
  	}

  	magic = fdt32_to_cpu(magic);

  	if (magic != FDT_MAGIC)
  		die("Blob has incorrect magic number
  ");

  	rc = fread(&totalsize, sizeof(totalsize), 1, f);
  	if (ferror(f))

  		die("Error reading DT blob size: %s
  ", strerror(errno));
  	if (rc < 1) {

  		if (feof(f))

  			die("EOF reading DT blob size
  ");
  		else
  			die("Mysterious short read reading blob size
  ");
  	}

  	totalsize = fdt32_to_cpu(totalsize);

  	if (totalsize < FDT_V1_SIZE)
  		die("DT blob size (%d) is too small
  ", 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
  ",
  			    totalsize);

  		rc = fread(p, 1, sizeleft, f);
  		if (ferror(f))

  			die("Error reading DT blob: %s
  ",
  			    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
  ");
  
  	if (off_dt >= totalsize)
  		die("DT structure offset exceeds total size
  ");
  
  	if (off_str > totalsize)
  		die("String table offset exceeds total size
  ");

  	if (version >= 3) {

  		uint32_t size_str = fdt32_to_cpu(fdt->size_dt_strings);

  		if (off_str+size_str > totalsize)
  			die("String table extends past total size
  ");

  		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 > totalsize)
  			die("Structure block extends past total size
  ");
  	}
  
  	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)
  ", 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
  ");
  
  	free(blob);

  	fclose(f);

  
  	return build_boot_info(reservelist, tree, boot_cpuid_phys);

  }