xref: /openbmc/linux/scripts/dtc/flattree.c (revision 95e9fd10)
1 /*
2  * (C) Copyright David Gibson <dwg@au1.ibm.com>, IBM Corporation.  2005.
3  *
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU General Public License as
7  * published by the Free Software Foundation; either version 2 of the
8  * License, or (at your option) any later version.
9  *
10  *  This program is distributed in the hope that it will be useful,
11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  *  General Public License for more details.
14  *
15  *  You should have received a copy of the GNU General Public License
16  *  along with this program; if not, write to the Free Software
17  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
18  *                                                                   USA
19  */
20 
21 #include "dtc.h"
22 #include "srcpos.h"
23 
24 #define FTF_FULLPATH	0x1
25 #define FTF_VARALIGN	0x2
26 #define FTF_NAMEPROPS	0x4
27 #define FTF_BOOTCPUID	0x8
28 #define FTF_STRTABSIZE	0x10
29 #define FTF_STRUCTSIZE	0x20
30 #define FTF_NOPS	0x40
31 
32 static struct version_info {
33 	int version;
34 	int last_comp_version;
35 	int hdr_size;
36 	int flags;
37 } version_table[] = {
38 	{1, 1, FDT_V1_SIZE,
39 	 FTF_FULLPATH|FTF_VARALIGN|FTF_NAMEPROPS},
40 	{2, 1, FDT_V2_SIZE,
41 	 FTF_FULLPATH|FTF_VARALIGN|FTF_NAMEPROPS|FTF_BOOTCPUID},
42 	{3, 1, FDT_V3_SIZE,
43 	 FTF_FULLPATH|FTF_VARALIGN|FTF_NAMEPROPS|FTF_BOOTCPUID|FTF_STRTABSIZE},
44 	{16, 16, FDT_V3_SIZE,
45 	 FTF_BOOTCPUID|FTF_STRTABSIZE|FTF_NOPS},
46 	{17, 16, FDT_V17_SIZE,
47 	 FTF_BOOTCPUID|FTF_STRTABSIZE|FTF_STRUCTSIZE|FTF_NOPS},
48 };
49 
50 struct emitter {
51 	void (*cell)(void *, cell_t);
52 	void (*string)(void *, char *, int);
53 	void (*align)(void *, int);
54 	void (*data)(void *, struct data);
55 	void (*beginnode)(void *, struct label *labels);
56 	void (*endnode)(void *, struct label *labels);
57 	void (*property)(void *, struct label *labels);
58 };
59 
60 static void bin_emit_cell(void *e, cell_t val)
61 {
62 	struct data *dtbuf = e;
63 
64 	*dtbuf = data_append_cell(*dtbuf, val);
65 }
66 
67 static void bin_emit_string(void *e, char *str, int len)
68 {
69 	struct data *dtbuf = e;
70 
71 	if (len == 0)
72 		len = strlen(str);
73 
74 	*dtbuf = data_append_data(*dtbuf, str, len);
75 	*dtbuf = data_append_byte(*dtbuf, '\0');
76 }
77 
78 static void bin_emit_align(void *e, int a)
79 {
80 	struct data *dtbuf = e;
81 
82 	*dtbuf = data_append_align(*dtbuf, a);
83 }
84 
85 static void bin_emit_data(void *e, struct data d)
86 {
87 	struct data *dtbuf = e;
88 
89 	*dtbuf = data_append_data(*dtbuf, d.val, d.len);
90 }
91 
92 static void bin_emit_beginnode(void *e, struct label *labels)
93 {
94 	bin_emit_cell(e, FDT_BEGIN_NODE);
95 }
96 
97 static void bin_emit_endnode(void *e, struct label *labels)
98 {
99 	bin_emit_cell(e, FDT_END_NODE);
100 }
101 
102 static void bin_emit_property(void *e, struct label *labels)
103 {
104 	bin_emit_cell(e, FDT_PROP);
105 }
106 
107 static struct emitter bin_emitter = {
108 	.cell = bin_emit_cell,
109 	.string = bin_emit_string,
110 	.align = bin_emit_align,
111 	.data = bin_emit_data,
112 	.beginnode = bin_emit_beginnode,
113 	.endnode = bin_emit_endnode,
114 	.property = bin_emit_property,
115 };
116 
117 static void emit_label(FILE *f, const char *prefix, const char *label)
118 {
119 	fprintf(f, "\t.globl\t%s_%s\n", prefix, label);
120 	fprintf(f, "%s_%s:\n", prefix, label);
121 	fprintf(f, "_%s_%s:\n", prefix, label);
122 }
123 
124 static void emit_offset_label(FILE *f, const char *label, int offset)
125 {
126 	fprintf(f, "\t.globl\t%s\n", label);
127 	fprintf(f, "%s\t= . + %d\n", label, offset);
128 }
129 
130 #define ASM_EMIT_BELONG(f, fmt, ...) \
131 	{ \
132 		fprintf((f), "\t.byte\t((" fmt ") >> 24) & 0xff\n", __VA_ARGS__); \
133 		fprintf((f), "\t.byte\t((" fmt ") >> 16) & 0xff\n", __VA_ARGS__); \
134 		fprintf((f), "\t.byte\t((" fmt ") >> 8) & 0xff\n", __VA_ARGS__); \
135 		fprintf((f), "\t.byte\t(" fmt ") & 0xff\n", __VA_ARGS__); \
136 	}
137 
138 static void asm_emit_cell(void *e, cell_t val)
139 {
140 	FILE *f = e;
141 
142 	fprintf(f, "\t.byte 0x%02x; .byte 0x%02x; .byte 0x%02x; .byte 0x%02x\n",
143 		(val >> 24) & 0xff, (val >> 16) & 0xff,
144 		(val >> 8) & 0xff, val & 0xff);
145 }
146 
147 static void asm_emit_string(void *e, char *str, int len)
148 {
149 	FILE *f = e;
150 	char c = 0;
151 
152 	if (len != 0) {
153 		/* XXX: ewww */
154 		c = str[len];
155 		str[len] = '\0';
156 	}
157 
158 	fprintf(f, "\t.string\t\"%s\"\n", str);
159 
160 	if (len != 0) {
161 		str[len] = c;
162 	}
163 }
164 
165 static void asm_emit_align(void *e, int a)
166 {
167 	FILE *f = e;
168 
169 	fprintf(f, "\t.balign\t%d, 0\n", a);
170 }
171 
172 static void asm_emit_data(void *e, struct data d)
173 {
174 	FILE *f = e;
175 	int off = 0;
176 	struct marker *m = d.markers;
177 
178 	for_each_marker_of_type(m, LABEL)
179 		emit_offset_label(f, m->ref, m->offset);
180 
181 	while ((d.len - off) >= sizeof(uint32_t)) {
182 		asm_emit_cell(e, fdt32_to_cpu(*((uint32_t *)(d.val+off))));
183 		off += sizeof(uint32_t);
184 	}
185 
186 	while ((d.len - off) >= 1) {
187 		fprintf(f, "\t.byte\t0x%hhx\n", d.val[off]);
188 		off += 1;
189 	}
190 
191 	assert(off == d.len);
192 }
193 
194 static void asm_emit_beginnode(void *e, struct label *labels)
195 {
196 	FILE *f = e;
197 	struct label *l;
198 
199 	for_each_label(labels, l) {
200 		fprintf(f, "\t.globl\t%s\n", l->label);
201 		fprintf(f, "%s:\n", l->label);
202 	}
203 	fprintf(f, "\t/* FDT_BEGIN_NODE */\n");
204 	asm_emit_cell(e, FDT_BEGIN_NODE);
205 }
206 
207 static void asm_emit_endnode(void *e, struct label *labels)
208 {
209 	FILE *f = e;
210 	struct label *l;
211 
212 	fprintf(f, "\t/* FDT_END_NODE */\n");
213 	asm_emit_cell(e, FDT_END_NODE);
214 	for_each_label(labels, l) {
215 		fprintf(f, "\t.globl\t%s_end\n", l->label);
216 		fprintf(f, "%s_end:\n", l->label);
217 	}
218 }
219 
220 static void asm_emit_property(void *e, struct label *labels)
221 {
222 	FILE *f = e;
223 	struct label *l;
224 
225 	for_each_label(labels, l) {
226 		fprintf(f, "\t.globl\t%s\n", l->label);
227 		fprintf(f, "%s:\n", l->label);
228 	}
229 	fprintf(f, "\t/* FDT_PROP */\n");
230 	asm_emit_cell(e, FDT_PROP);
231 }
232 
233 static struct emitter asm_emitter = {
234 	.cell = asm_emit_cell,
235 	.string = asm_emit_string,
236 	.align = asm_emit_align,
237 	.data = asm_emit_data,
238 	.beginnode = asm_emit_beginnode,
239 	.endnode = asm_emit_endnode,
240 	.property = asm_emit_property,
241 };
242 
243 static int stringtable_insert(struct data *d, const char *str)
244 {
245 	int i;
246 
247 	/* FIXME: do this more efficiently? */
248 
249 	for (i = 0; i < d->len; i++) {
250 		if (streq(str, d->val + i))
251 			return i;
252 	}
253 
254 	*d = data_append_data(*d, str, strlen(str)+1);
255 	return i;
256 }
257 
258 static void flatten_tree(struct node *tree, struct emitter *emit,
259 			 void *etarget, struct data *strbuf,
260 			 struct version_info *vi)
261 {
262 	struct property *prop;
263 	struct node *child;
264 	int seen_name_prop = 0;
265 
266 	emit->beginnode(etarget, tree->labels);
267 
268 	if (vi->flags & FTF_FULLPATH)
269 		emit->string(etarget, tree->fullpath, 0);
270 	else
271 		emit->string(etarget, tree->name, 0);
272 
273 	emit->align(etarget, sizeof(cell_t));
274 
275 	for_each_property(tree, prop) {
276 		int nameoff;
277 
278 		if (streq(prop->name, "name"))
279 			seen_name_prop = 1;
280 
281 		nameoff = stringtable_insert(strbuf, prop->name);
282 
283 		emit->property(etarget, prop->labels);
284 		emit->cell(etarget, prop->val.len);
285 		emit->cell(etarget, nameoff);
286 
287 		if ((vi->flags & FTF_VARALIGN) && (prop->val.len >= 8))
288 			emit->align(etarget, 8);
289 
290 		emit->data(etarget, prop->val);
291 		emit->align(etarget, sizeof(cell_t));
292 	}
293 
294 	if ((vi->flags & FTF_NAMEPROPS) && !seen_name_prop) {
295 		emit->property(etarget, NULL);
296 		emit->cell(etarget, tree->basenamelen+1);
297 		emit->cell(etarget, stringtable_insert(strbuf, "name"));
298 
299 		if ((vi->flags & FTF_VARALIGN) && ((tree->basenamelen+1) >= 8))
300 			emit->align(etarget, 8);
301 
302 		emit->string(etarget, tree->name, tree->basenamelen);
303 		emit->align(etarget, sizeof(cell_t));
304 	}
305 
306 	for_each_child(tree, child) {
307 		flatten_tree(child, emit, etarget, strbuf, vi);
308 	}
309 
310 	emit->endnode(etarget, tree->labels);
311 }
312 
313 static struct data flatten_reserve_list(struct reserve_info *reservelist,
314 				 struct version_info *vi)
315 {
316 	struct reserve_info *re;
317 	struct data d = empty_data;
318 	static struct fdt_reserve_entry null_re = {0,0};
319 	int    j;
320 
321 	for (re = reservelist; re; re = re->next) {
322 		d = data_append_re(d, &re->re);
323 	}
324 	/*
325 	 * Add additional reserved slots if the user asked for them.
326 	 */
327 	for (j = 0; j < reservenum; j++) {
328 		d = data_append_re(d, &null_re);
329 	}
330 
331 	return d;
332 }
333 
334 static void make_fdt_header(struct fdt_header *fdt,
335 			    struct version_info *vi,
336 			    int reservesize, int dtsize, int strsize,
337 			    int boot_cpuid_phys)
338 {
339 	int reserve_off;
340 
341 	reservesize += sizeof(struct fdt_reserve_entry);
342 
343 	memset(fdt, 0xff, sizeof(*fdt));
344 
345 	fdt->magic = cpu_to_fdt32(FDT_MAGIC);
346 	fdt->version = cpu_to_fdt32(vi->version);
347 	fdt->last_comp_version = cpu_to_fdt32(vi->last_comp_version);
348 
349 	/* Reserve map should be doubleword aligned */
350 	reserve_off = ALIGN(vi->hdr_size, 8);
351 
352 	fdt->off_mem_rsvmap = cpu_to_fdt32(reserve_off);
353 	fdt->off_dt_struct = cpu_to_fdt32(reserve_off + reservesize);
354 	fdt->off_dt_strings = cpu_to_fdt32(reserve_off + reservesize
355 					  + dtsize);
356 	fdt->totalsize = cpu_to_fdt32(reserve_off + reservesize + dtsize + strsize);
357 
358 	if (vi->flags & FTF_BOOTCPUID)
359 		fdt->boot_cpuid_phys = cpu_to_fdt32(boot_cpuid_phys);
360 	if (vi->flags & FTF_STRTABSIZE)
361 		fdt->size_dt_strings = cpu_to_fdt32(strsize);
362 	if (vi->flags & FTF_STRUCTSIZE)
363 		fdt->size_dt_struct = cpu_to_fdt32(dtsize);
364 }
365 
366 void dt_to_blob(FILE *f, struct boot_info *bi, int version)
367 {
368 	struct version_info *vi = NULL;
369 	int i;
370 	struct data blob       = empty_data;
371 	struct data reservebuf = empty_data;
372 	struct data dtbuf      = empty_data;
373 	struct data strbuf     = empty_data;
374 	struct fdt_header fdt;
375 	int padlen = 0;
376 
377 	for (i = 0; i < ARRAY_SIZE(version_table); i++) {
378 		if (version_table[i].version == version)
379 			vi = &version_table[i];
380 	}
381 	if (!vi)
382 		die("Unknown device tree blob version %d\n", version);
383 
384 	flatten_tree(bi->dt, &bin_emitter, &dtbuf, &strbuf, vi);
385 	bin_emit_cell(&dtbuf, FDT_END);
386 
387 	reservebuf = flatten_reserve_list(bi->reservelist, vi);
388 
389 	/* Make header */
390 	make_fdt_header(&fdt, vi, reservebuf.len, dtbuf.len, strbuf.len,
391 			bi->boot_cpuid_phys);
392 
393 	/*
394 	 * If the user asked for more space than is used, adjust the totalsize.
395 	 */
396 	if (minsize > 0) {
397 		padlen = minsize - fdt32_to_cpu(fdt.totalsize);
398 		if ((padlen < 0) && (quiet < 1))
399 			fprintf(stderr,
400 				"Warning: blob size %d >= minimum size %d\n",
401 				fdt32_to_cpu(fdt.totalsize), minsize);
402 	}
403 
404 	if (padsize > 0)
405 		padlen = padsize;
406 
407 	if (padlen > 0) {
408 		int tsize = fdt32_to_cpu(fdt.totalsize);
409 		tsize += padlen;
410 		fdt.totalsize = cpu_to_fdt32(tsize);
411 	}
412 
413 	/*
414 	 * Assemble the blob: start with the header, add with alignment
415 	 * the reserve buffer, add the reserve map terminating zeroes,
416 	 * the device tree itself, and finally the strings.
417 	 */
418 	blob = data_append_data(blob, &fdt, vi->hdr_size);
419 	blob = data_append_align(blob, 8);
420 	blob = data_merge(blob, reservebuf);
421 	blob = data_append_zeroes(blob, sizeof(struct fdt_reserve_entry));
422 	blob = data_merge(blob, dtbuf);
423 	blob = data_merge(blob, strbuf);
424 
425 	/*
426 	 * If the user asked for more space than is used, pad out the blob.
427 	 */
428 	if (padlen > 0)
429 		blob = data_append_zeroes(blob, padlen);
430 
431 	if (fwrite(blob.val, blob.len, 1, f) != 1) {
432 		if (ferror(f))
433 			die("Error writing device tree blob: %s\n",
434 			    strerror(errno));
435 		else
436 			die("Short write on device tree blob\n");
437 	}
438 
439 	/*
440 	 * data_merge() frees the right-hand element so only the blob
441 	 * remains to be freed.
442 	 */
443 	data_free(blob);
444 }
445 
446 static void dump_stringtable_asm(FILE *f, struct data strbuf)
447 {
448 	const char *p;
449 	int len;
450 
451 	p = strbuf.val;
452 
453 	while (p < (strbuf.val + strbuf.len)) {
454 		len = strlen(p);
455 		fprintf(f, "\t.string \"%s\"\n", p);
456 		p += len+1;
457 	}
458 }
459 
460 void dt_to_asm(FILE *f, struct boot_info *bi, int version)
461 {
462 	struct version_info *vi = NULL;
463 	int i;
464 	struct data strbuf = empty_data;
465 	struct reserve_info *re;
466 	const char *symprefix = "dt";
467 
468 	for (i = 0; i < ARRAY_SIZE(version_table); i++) {
469 		if (version_table[i].version == version)
470 			vi = &version_table[i];
471 	}
472 	if (!vi)
473 		die("Unknown device tree blob version %d\n", version);
474 
475 	fprintf(f, "/* autogenerated by dtc, do not edit */\n\n");
476 
477 	emit_label(f, symprefix, "blob_start");
478 	emit_label(f, symprefix, "header");
479 	fprintf(f, "\t/* magic */\n");
480 	asm_emit_cell(f, FDT_MAGIC);
481 	fprintf(f, "\t/* totalsize */\n");
482 	ASM_EMIT_BELONG(f, "_%s_blob_abs_end - _%s_blob_start",
483 			symprefix, symprefix);
484 	fprintf(f, "\t/* off_dt_struct */\n");
485 	ASM_EMIT_BELONG(f, "_%s_struct_start - _%s_blob_start",
486 		symprefix, symprefix);
487 	fprintf(f, "\t/* off_dt_strings */\n");
488 	ASM_EMIT_BELONG(f, "_%s_strings_start - _%s_blob_start",
489 		symprefix, symprefix);
490 	fprintf(f, "\t/* off_mem_rsvmap */\n");
491 	ASM_EMIT_BELONG(f, "_%s_reserve_map - _%s_blob_start",
492 		symprefix, symprefix);
493 	fprintf(f, "\t/* version */\n");
494 	asm_emit_cell(f, vi->version);
495 	fprintf(f, "\t/* last_comp_version */\n");
496 	asm_emit_cell(f, vi->last_comp_version);
497 
498 	if (vi->flags & FTF_BOOTCPUID) {
499 		fprintf(f, "\t/* boot_cpuid_phys */\n");
500 		asm_emit_cell(f, bi->boot_cpuid_phys);
501 	}
502 
503 	if (vi->flags & FTF_STRTABSIZE) {
504 		fprintf(f, "\t/* size_dt_strings */\n");
505 		ASM_EMIT_BELONG(f, "_%s_strings_end - _%s_strings_start",
506 				symprefix, symprefix);
507 	}
508 
509 	if (vi->flags & FTF_STRUCTSIZE) {
510 		fprintf(f, "\t/* size_dt_struct */\n");
511 		ASM_EMIT_BELONG(f, "_%s_struct_end - _%s_struct_start",
512 			symprefix, symprefix);
513 	}
514 
515 	/*
516 	 * Reserve map entries.
517 	 * Align the reserve map to a doubleword boundary.
518 	 * Each entry is an (address, size) pair of u64 values.
519 	 * Always supply a zero-sized temination entry.
520 	 */
521 	asm_emit_align(f, 8);
522 	emit_label(f, symprefix, "reserve_map");
523 
524 	fprintf(f, "/* Memory reserve map from source file */\n");
525 
526 	/*
527 	 * Use .long on high and low halfs of u64s to avoid .quad
528 	 * as it appears .quad isn't available in some assemblers.
529 	 */
530 	for (re = bi->reservelist; re; re = re->next) {
531 		struct label *l;
532 
533 		for_each_label(re->labels, l) {
534 			fprintf(f, "\t.globl\t%s\n", l->label);
535 			fprintf(f, "%s:\n", l->label);
536 		}
537 		ASM_EMIT_BELONG(f, "0x%08x", (unsigned int)(re->re.address >> 32));
538 		ASM_EMIT_BELONG(f, "0x%08x",
539 				(unsigned int)(re->re.address & 0xffffffff));
540 		ASM_EMIT_BELONG(f, "0x%08x", (unsigned int)(re->re.size >> 32));
541 		ASM_EMIT_BELONG(f, "0x%08x", (unsigned int)(re->re.size & 0xffffffff));
542 	}
543 	for (i = 0; i < reservenum; i++) {
544 		fprintf(f, "\t.long\t0, 0\n\t.long\t0, 0\n");
545 	}
546 
547 	fprintf(f, "\t.long\t0, 0\n\t.long\t0, 0\n");
548 
549 	emit_label(f, symprefix, "struct_start");
550 	flatten_tree(bi->dt, &asm_emitter, f, &strbuf, vi);
551 
552 	fprintf(f, "\t/* FDT_END */\n");
553 	asm_emit_cell(f, FDT_END);
554 	emit_label(f, symprefix, "struct_end");
555 
556 	emit_label(f, symprefix, "strings_start");
557 	dump_stringtable_asm(f, strbuf);
558 	emit_label(f, symprefix, "strings_end");
559 
560 	emit_label(f, symprefix, "blob_end");
561 
562 	/*
563 	 * If the user asked for more space than is used, pad it out.
564 	 */
565 	if (minsize > 0) {
566 		fprintf(f, "\t.space\t%d - (_%s_blob_end - _%s_blob_start), 0\n",
567 			minsize, symprefix, symprefix);
568 	}
569 	if (padsize > 0) {
570 		fprintf(f, "\t.space\t%d, 0\n", padsize);
571 	}
572 	emit_label(f, symprefix, "blob_abs_end");
573 
574 	data_free(strbuf);
575 }
576 
577 struct inbuf {
578 	char *base, *limit, *ptr;
579 };
580 
581 static void inbuf_init(struct inbuf *inb, void *base, void *limit)
582 {
583 	inb->base = base;
584 	inb->limit = limit;
585 	inb->ptr = inb->base;
586 }
587 
588 static void flat_read_chunk(struct inbuf *inb, void *p, int len)
589 {
590 	if ((inb->ptr + len) > inb->limit)
591 		die("Premature end of data parsing flat device tree\n");
592 
593 	memcpy(p, inb->ptr, len);
594 
595 	inb->ptr += len;
596 }
597 
598 static uint32_t flat_read_word(struct inbuf *inb)
599 {
600 	uint32_t val;
601 
602 	assert(((inb->ptr - inb->base) % sizeof(val)) == 0);
603 
604 	flat_read_chunk(inb, &val, sizeof(val));
605 
606 	return fdt32_to_cpu(val);
607 }
608 
609 static void flat_realign(struct inbuf *inb, int align)
610 {
611 	int off = inb->ptr - inb->base;
612 
613 	inb->ptr = inb->base + ALIGN(off, align);
614 	if (inb->ptr > inb->limit)
615 		die("Premature end of data parsing flat device tree\n");
616 }
617 
618 static char *flat_read_string(struct inbuf *inb)
619 {
620 	int len = 0;
621 	const char *p = inb->ptr;
622 	char *str;
623 
624 	do {
625 		if (p >= inb->limit)
626 			die("Premature end of data parsing flat device tree\n");
627 		len++;
628 	} while ((*p++) != '\0');
629 
630 	str = xstrdup(inb->ptr);
631 
632 	inb->ptr += len;
633 
634 	flat_realign(inb, sizeof(uint32_t));
635 
636 	return str;
637 }
638 
639 static struct data flat_read_data(struct inbuf *inb, int len)
640 {
641 	struct data d = empty_data;
642 
643 	if (len == 0)
644 		return empty_data;
645 
646 	d = data_grow_for(d, len);
647 	d.len = len;
648 
649 	flat_read_chunk(inb, d.val, len);
650 
651 	flat_realign(inb, sizeof(uint32_t));
652 
653 	return d;
654 }
655 
656 static char *flat_read_stringtable(struct inbuf *inb, int offset)
657 {
658 	const char *p;
659 
660 	p = inb->base + offset;
661 	while (1) {
662 		if (p >= inb->limit || p < inb->base)
663 			die("String offset %d overruns string table\n",
664 			    offset);
665 
666 		if (*p == '\0')
667 			break;
668 
669 		p++;
670 	}
671 
672 	return xstrdup(inb->base + offset);
673 }
674 
675 static struct property *flat_read_property(struct inbuf *dtbuf,
676 					   struct inbuf *strbuf, int flags)
677 {
678 	uint32_t proplen, stroff;
679 	char *name;
680 	struct data val;
681 
682 	proplen = flat_read_word(dtbuf);
683 	stroff = flat_read_word(dtbuf);
684 
685 	name = flat_read_stringtable(strbuf, stroff);
686 
687 	if ((flags & FTF_VARALIGN) && (proplen >= 8))
688 		flat_realign(dtbuf, 8);
689 
690 	val = flat_read_data(dtbuf, proplen);
691 
692 	return build_property(name, val);
693 }
694 
695 
696 static struct reserve_info *flat_read_mem_reserve(struct inbuf *inb)
697 {
698 	struct reserve_info *reservelist = NULL;
699 	struct reserve_info *new;
700 	struct fdt_reserve_entry re;
701 
702 	/*
703 	 * Each entry is a pair of u64 (addr, size) values for 4 cell_t's.
704 	 * List terminates at an entry with size equal to zero.
705 	 *
706 	 * First pass, count entries.
707 	 */
708 	while (1) {
709 		flat_read_chunk(inb, &re, sizeof(re));
710 		re.address  = fdt64_to_cpu(re.address);
711 		re.size = fdt64_to_cpu(re.size);
712 		if (re.size == 0)
713 			break;
714 
715 		new = build_reserve_entry(re.address, re.size);
716 		reservelist = add_reserve_entry(reservelist, new);
717 	}
718 
719 	return reservelist;
720 }
721 
722 
723 static char *nodename_from_path(const char *ppath, const char *cpath)
724 {
725 	int plen;
726 
727 	plen = strlen(ppath);
728 
729 	if (!strneq(ppath, cpath, plen))
730 		die("Path \"%s\" is not valid as a child of \"%s\"\n",
731 		    cpath, ppath);
732 
733 	/* root node is a special case */
734 	if (!streq(ppath, "/"))
735 		plen++;
736 
737 	return xstrdup(cpath + plen);
738 }
739 
740 static struct node *unflatten_tree(struct inbuf *dtbuf,
741 				   struct inbuf *strbuf,
742 				   const char *parent_flatname, int flags)
743 {
744 	struct node *node;
745 	char *flatname;
746 	uint32_t val;
747 
748 	node = build_node(NULL, NULL);
749 
750 	flatname = flat_read_string(dtbuf);
751 
752 	if (flags & FTF_FULLPATH)
753 		node->name = nodename_from_path(parent_flatname, flatname);
754 	else
755 		node->name = flatname;
756 
757 	do {
758 		struct property *prop;
759 		struct node *child;
760 
761 		val = flat_read_word(dtbuf);
762 		switch (val) {
763 		case FDT_PROP:
764 			if (node->children)
765 				fprintf(stderr, "Warning: Flat tree input has "
766 					"subnodes preceding a property.\n");
767 			prop = flat_read_property(dtbuf, strbuf, flags);
768 			add_property(node, prop);
769 			break;
770 
771 		case FDT_BEGIN_NODE:
772 			child = unflatten_tree(dtbuf,strbuf, flatname, flags);
773 			add_child(node, child);
774 			break;
775 
776 		case FDT_END_NODE:
777 			break;
778 
779 		case FDT_END:
780 			die("Premature FDT_END in device tree blob\n");
781 			break;
782 
783 		case FDT_NOP:
784 			if (!(flags & FTF_NOPS))
785 				fprintf(stderr, "Warning: NOP tag found in flat tree"
786 					" version <16\n");
787 
788 			/* Ignore */
789 			break;
790 
791 		default:
792 			die("Invalid opcode word %08x in device tree blob\n",
793 			    val);
794 		}
795 	} while (val != FDT_END_NODE);
796 
797 	return node;
798 }
799 
800 
801 struct boot_info *dt_from_blob(const char *fname)
802 {
803 	FILE *f;
804 	uint32_t magic, totalsize, version, size_dt, boot_cpuid_phys;
805 	uint32_t off_dt, off_str, off_mem_rsvmap;
806 	int rc;
807 	char *blob;
808 	struct fdt_header *fdt;
809 	char *p;
810 	struct inbuf dtbuf, strbuf;
811 	struct inbuf memresvbuf;
812 	int sizeleft;
813 	struct reserve_info *reservelist;
814 	struct node *tree;
815 	uint32_t val;
816 	int flags = 0;
817 
818 	f = srcfile_relative_open(fname, NULL);
819 
820 	rc = fread(&magic, sizeof(magic), 1, f);
821 	if (ferror(f))
822 		die("Error reading DT blob magic number: %s\n",
823 		    strerror(errno));
824 	if (rc < 1) {
825 		if (feof(f))
826 			die("EOF reading DT blob magic number\n");
827 		else
828 			die("Mysterious short read reading magic number\n");
829 	}
830 
831 	magic = fdt32_to_cpu(magic);
832 	if (magic != FDT_MAGIC)
833 		die("Blob has incorrect magic number\n");
834 
835 	rc = fread(&totalsize, sizeof(totalsize), 1, f);
836 	if (ferror(f))
837 		die("Error reading DT blob size: %s\n", strerror(errno));
838 	if (rc < 1) {
839 		if (feof(f))
840 			die("EOF reading DT blob size\n");
841 		else
842 			die("Mysterious short read reading blob size\n");
843 	}
844 
845 	totalsize = fdt32_to_cpu(totalsize);
846 	if (totalsize < FDT_V1_SIZE)
847 		die("DT blob size (%d) is too small\n", totalsize);
848 
849 	blob = xmalloc(totalsize);
850 
851 	fdt = (struct fdt_header *)blob;
852 	fdt->magic = cpu_to_fdt32(magic);
853 	fdt->totalsize = cpu_to_fdt32(totalsize);
854 
855 	sizeleft = totalsize - sizeof(magic) - sizeof(totalsize);
856 	p = blob + sizeof(magic)  + sizeof(totalsize);
857 
858 	while (sizeleft) {
859 		if (feof(f))
860 			die("EOF before reading %d bytes of DT blob\n",
861 			    totalsize);
862 
863 		rc = fread(p, 1, sizeleft, f);
864 		if (ferror(f))
865 			die("Error reading DT blob: %s\n",
866 			    strerror(errno));
867 
868 		sizeleft -= rc;
869 		p += rc;
870 	}
871 
872 	off_dt = fdt32_to_cpu(fdt->off_dt_struct);
873 	off_str = fdt32_to_cpu(fdt->off_dt_strings);
874 	off_mem_rsvmap = fdt32_to_cpu(fdt->off_mem_rsvmap);
875 	version = fdt32_to_cpu(fdt->version);
876 	boot_cpuid_phys = fdt32_to_cpu(fdt->boot_cpuid_phys);
877 
878 	if (off_mem_rsvmap >= totalsize)
879 		die("Mem Reserve structure offset exceeds total size\n");
880 
881 	if (off_dt >= totalsize)
882 		die("DT structure offset exceeds total size\n");
883 
884 	if (off_str > totalsize)
885 		die("String table offset exceeds total size\n");
886 
887 	if (version >= 3) {
888 		uint32_t size_str = fdt32_to_cpu(fdt->size_dt_strings);
889 		if (off_str+size_str > totalsize)
890 			die("String table extends past total size\n");
891 		inbuf_init(&strbuf, blob + off_str, blob + off_str + size_str);
892 	} else {
893 		inbuf_init(&strbuf, blob + off_str, blob + totalsize);
894 	}
895 
896 	if (version >= 17) {
897 		size_dt = fdt32_to_cpu(fdt->size_dt_struct);
898 		if (off_dt+size_dt > totalsize)
899 			die("Structure block extends past total size\n");
900 	}
901 
902 	if (version < 16) {
903 		flags |= FTF_FULLPATH | FTF_NAMEPROPS | FTF_VARALIGN;
904 	} else {
905 		flags |= FTF_NOPS;
906 	}
907 
908 	inbuf_init(&memresvbuf,
909 		   blob + off_mem_rsvmap, blob + totalsize);
910 	inbuf_init(&dtbuf, blob + off_dt, blob + totalsize);
911 
912 	reservelist = flat_read_mem_reserve(&memresvbuf);
913 
914 	val = flat_read_word(&dtbuf);
915 
916 	if (val != FDT_BEGIN_NODE)
917 		die("Device tree blob doesn't begin with FDT_BEGIN_NODE (begins with 0x%08x)\n", val);
918 
919 	tree = unflatten_tree(&dtbuf, &strbuf, "", flags);
920 
921 	val = flat_read_word(&dtbuf);
922 	if (val != FDT_END)
923 		die("Device tree blob doesn't end with FDT_END\n");
924 
925 	free(blob);
926 
927 	fclose(f);
928 
929 	return build_boot_info(reservelist, tree, boot_cpuid_phys);
930 }
931