1 // SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
2 /*
3 * libfdt - Flat Device Tree manipulation
4 * Copyright (C) 2016 Free Electrons
5 * Copyright (C) 2016 NextThing Co.
6 */
7 #include "libfdt_env.h"
8
9 #include <fdt.h>
10 #include <libfdt.h>
11
12 #include "libfdt_internal.h"
13
14 /**
15 * overlay_get_target_phandle - retrieves the target phandle of a fragment
16 * @fdto: pointer to the device tree overlay blob
17 * @fragment: node offset of the fragment in the overlay
18 *
19 * overlay_get_target_phandle() retrieves the target phandle of an
20 * overlay fragment when that fragment uses a phandle (target
21 * property) instead of a path (target-path property).
22 *
23 * returns:
24 * the phandle pointed by the target property
25 * 0, if the phandle was not found
26 * -1, if the phandle was malformed
27 */
overlay_get_target_phandle(const void * fdto,int fragment)28 static uint32_t overlay_get_target_phandle(const void *fdto, int fragment)
29 {
30 const fdt32_t *val;
31 int len;
32
33 val = fdt_getprop(fdto, fragment, "target", &len);
34 if (!val)
35 return 0;
36
37 if ((len != sizeof(*val)) || (fdt32_to_cpu(*val) == (uint32_t)-1))
38 return (uint32_t)-1;
39
40 return fdt32_to_cpu(*val);
41 }
42
fdt_overlay_target_offset(const void * fdt,const void * fdto,int fragment_offset,char const ** pathp)43 int fdt_overlay_target_offset(const void *fdt, const void *fdto,
44 int fragment_offset, char const **pathp)
45 {
46 uint32_t phandle;
47 const char *path = NULL;
48 int path_len = 0, ret;
49
50 /* Try first to do a phandle based lookup */
51 phandle = overlay_get_target_phandle(fdto, fragment_offset);
52 if (phandle == (uint32_t)-1)
53 return -FDT_ERR_BADPHANDLE;
54
55 /* no phandle, try path */
56 if (!phandle) {
57 /* And then a path based lookup */
58 path = fdt_getprop(fdto, fragment_offset, "target-path", &path_len);
59 if (path)
60 ret = fdt_path_offset(fdt, path);
61 else
62 ret = path_len;
63 } else
64 ret = fdt_node_offset_by_phandle(fdt, phandle);
65
66 /*
67 * If we haven't found either a target or a
68 * target-path property in a node that contains a
69 * __overlay__ subnode (we wouldn't be called
70 * otherwise), consider it a improperly written
71 * overlay
72 */
73 if (ret < 0 && path_len == -FDT_ERR_NOTFOUND)
74 ret = -FDT_ERR_BADOVERLAY;
75
76 /* return on error */
77 if (ret < 0)
78 return ret;
79
80 /* return pointer to path (if available) */
81 if (pathp)
82 *pathp = path ? path : NULL;
83
84 return ret;
85 }
86
87 /**
88 * overlay_phandle_add_offset - Increases a phandle by an offset
89 * @fdt: Base device tree blob
90 * @node: Device tree overlay blob
91 * @name: Name of the property to modify (phandle or linux,phandle)
92 * @delta: offset to apply
93 *
94 * overlay_phandle_add_offset() increments a node phandle by a given
95 * offset.
96 *
97 * returns:
98 * 0 on success.
99 * Negative error code on error
100 */
overlay_phandle_add_offset(void * fdt,int node,const char * name,uint32_t delta)101 static int overlay_phandle_add_offset(void *fdt, int node,
102 const char *name, uint32_t delta)
103 {
104 const fdt32_t *val;
105 uint32_t adj_val;
106 int len;
107
108 val = fdt_getprop(fdt, node, name, &len);
109 if (!val)
110 return len;
111
112 if (len != sizeof(*val))
113 return -FDT_ERR_BADPHANDLE;
114
115 adj_val = fdt32_to_cpu(*val);
116 if ((adj_val + delta) < adj_val)
117 return -FDT_ERR_NOPHANDLES;
118
119 adj_val += delta;
120 if (adj_val == (uint32_t)-1)
121 return -FDT_ERR_NOPHANDLES;
122
123 return fdt_setprop_inplace_u32(fdt, node, name, adj_val);
124 }
125
126 /**
127 * overlay_adjust_node_phandles - Offsets the phandles of a node
128 * @fdto: Device tree overlay blob
129 * @node: Offset of the node we want to adjust
130 * @delta: Offset to shift the phandles of
131 *
132 * overlay_adjust_node_phandles() adds a constant to all the phandles
133 * of a given node. This is mainly use as part of the overlay
134 * application process, when we want to update all the overlay
135 * phandles to not conflict with the overlays of the base device tree.
136 *
137 * returns:
138 * 0 on success
139 * Negative error code on failure
140 */
overlay_adjust_node_phandles(void * fdto,int node,uint32_t delta)141 static int overlay_adjust_node_phandles(void *fdto, int node,
142 uint32_t delta)
143 {
144 int child;
145 int ret;
146
147 ret = overlay_phandle_add_offset(fdto, node, "phandle", delta);
148 if (ret && ret != -FDT_ERR_NOTFOUND)
149 return ret;
150
151 ret = overlay_phandle_add_offset(fdto, node, "linux,phandle", delta);
152 if (ret && ret != -FDT_ERR_NOTFOUND)
153 return ret;
154
155 fdt_for_each_subnode(child, fdto, node) {
156 ret = overlay_adjust_node_phandles(fdto, child, delta);
157 if (ret)
158 return ret;
159 }
160
161 return 0;
162 }
163
164 /**
165 * overlay_adjust_local_phandles - Adjust the phandles of a whole overlay
166 * @fdto: Device tree overlay blob
167 * @delta: Offset to shift the phandles of
168 *
169 * overlay_adjust_local_phandles() adds a constant to all the
170 * phandles of an overlay. This is mainly use as part of the overlay
171 * application process, when we want to update all the overlay
172 * phandles to not conflict with the overlays of the base device tree.
173 *
174 * returns:
175 * 0 on success
176 * Negative error code on failure
177 */
overlay_adjust_local_phandles(void * fdto,uint32_t delta)178 static int overlay_adjust_local_phandles(void *fdto, uint32_t delta)
179 {
180 /*
181 * Start adjusting the phandles from the overlay root
182 */
183 return overlay_adjust_node_phandles(fdto, 0, delta);
184 }
185
186 /**
187 * overlay_update_local_node_references - Adjust the overlay references
188 * @fdto: Device tree overlay blob
189 * @tree_node: Node offset of the node to operate on
190 * @fixup_node: Node offset of the matching local fixups node
191 * @delta: Offset to shift the phandles of
192 *
193 * overlay_update_local_nodes_references() update the phandles
194 * pointing to a node within the device tree overlay by adding a
195 * constant delta.
196 *
197 * This is mainly used as part of a device tree application process,
198 * where you want the device tree overlays phandles to not conflict
199 * with the ones from the base device tree before merging them.
200 *
201 * returns:
202 * 0 on success
203 * Negative error code on failure
204 */
overlay_update_local_node_references(void * fdto,int tree_node,int fixup_node,uint32_t delta)205 static int overlay_update_local_node_references(void *fdto,
206 int tree_node,
207 int fixup_node,
208 uint32_t delta)
209 {
210 int fixup_prop;
211 int fixup_child;
212 int ret;
213
214 fdt_for_each_property_offset(fixup_prop, fdto, fixup_node) {
215 const fdt32_t *fixup_val;
216 const char *tree_val;
217 const char *name;
218 int fixup_len;
219 int tree_len;
220 int i;
221
222 fixup_val = fdt_getprop_by_offset(fdto, fixup_prop,
223 &name, &fixup_len);
224 if (!fixup_val)
225 return fixup_len;
226
227 if (fixup_len % sizeof(uint32_t))
228 return -FDT_ERR_BADOVERLAY;
229 fixup_len /= sizeof(uint32_t);
230
231 tree_val = fdt_getprop(fdto, tree_node, name, &tree_len);
232 if (!tree_val) {
233 if (tree_len == -FDT_ERR_NOTFOUND)
234 return -FDT_ERR_BADOVERLAY;
235
236 return tree_len;
237 }
238
239 for (i = 0; i < fixup_len; i++) {
240 fdt32_t adj_val;
241 uint32_t poffset;
242
243 poffset = fdt32_to_cpu(fixup_val[i]);
244
245 /*
246 * phandles to fixup can be unaligned.
247 *
248 * Use a memcpy for the architectures that do
249 * not support unaligned accesses.
250 */
251 memcpy(&adj_val, tree_val + poffset, sizeof(adj_val));
252
253 adj_val = cpu_to_fdt32(fdt32_to_cpu(adj_val) + delta);
254
255 ret = fdt_setprop_inplace_namelen_partial(fdto,
256 tree_node,
257 name,
258 strlen(name),
259 poffset,
260 &adj_val,
261 sizeof(adj_val));
262 if (ret == -FDT_ERR_NOSPACE)
263 return -FDT_ERR_BADOVERLAY;
264
265 if (ret)
266 return ret;
267 }
268 }
269
270 fdt_for_each_subnode(fixup_child, fdto, fixup_node) {
271 const char *fixup_child_name = fdt_get_name(fdto, fixup_child,
272 NULL);
273 int tree_child;
274
275 tree_child = fdt_subnode_offset(fdto, tree_node,
276 fixup_child_name);
277 if (tree_child == -FDT_ERR_NOTFOUND)
278 return -FDT_ERR_BADOVERLAY;
279 if (tree_child < 0)
280 return tree_child;
281
282 ret = overlay_update_local_node_references(fdto,
283 tree_child,
284 fixup_child,
285 delta);
286 if (ret)
287 return ret;
288 }
289
290 return 0;
291 }
292
293 /**
294 * overlay_update_local_references - Adjust the overlay references
295 * @fdto: Device tree overlay blob
296 * @delta: Offset to shift the phandles of
297 *
298 * overlay_update_local_references() update all the phandles pointing
299 * to a node within the device tree overlay by adding a constant
300 * delta to not conflict with the base overlay.
301 *
302 * This is mainly used as part of a device tree application process,
303 * where you want the device tree overlays phandles to not conflict
304 * with the ones from the base device tree before merging them.
305 *
306 * returns:
307 * 0 on success
308 * Negative error code on failure
309 */
overlay_update_local_references(void * fdto,uint32_t delta)310 static int overlay_update_local_references(void *fdto, uint32_t delta)
311 {
312 int fixups;
313
314 fixups = fdt_path_offset(fdto, "/__local_fixups__");
315 if (fixups < 0) {
316 /* There's no local phandles to adjust, bail out */
317 if (fixups == -FDT_ERR_NOTFOUND)
318 return 0;
319
320 return fixups;
321 }
322
323 /*
324 * Update our local references from the root of the tree
325 */
326 return overlay_update_local_node_references(fdto, 0, fixups,
327 delta);
328 }
329
330 /**
331 * overlay_fixup_one_phandle - Set an overlay phandle to the base one
332 * @fdt: Base Device Tree blob
333 * @fdto: Device tree overlay blob
334 * @symbols_off: Node offset of the symbols node in the base device tree
335 * @path: Path to a node holding a phandle in the overlay
336 * @path_len: number of path characters to consider
337 * @name: Name of the property holding the phandle reference in the overlay
338 * @name_len: number of name characters to consider
339 * @poffset: Offset within the overlay property where the phandle is stored
340 * @label: Label of the node referenced by the phandle
341 *
342 * overlay_fixup_one_phandle() resolves an overlay phandle pointing to
343 * a node in the base device tree.
344 *
345 * This is part of the device tree overlay application process, when
346 * you want all the phandles in the overlay to point to the actual
347 * base dt nodes.
348 *
349 * returns:
350 * 0 on success
351 * Negative error code on failure
352 */
overlay_fixup_one_phandle(void * fdt,void * fdto,int symbols_off,const char * path,uint32_t path_len,const char * name,uint32_t name_len,int poffset,const char * label)353 static int overlay_fixup_one_phandle(void *fdt, void *fdto,
354 int symbols_off,
355 const char *path, uint32_t path_len,
356 const char *name, uint32_t name_len,
357 int poffset, const char *label)
358 {
359 const char *symbol_path;
360 uint32_t phandle;
361 fdt32_t phandle_prop;
362 int symbol_off, fixup_off;
363 int prop_len;
364
365 if (symbols_off < 0)
366 return symbols_off;
367
368 symbol_path = fdt_getprop(fdt, symbols_off, label,
369 &prop_len);
370 if (!symbol_path)
371 return prop_len;
372
373 symbol_off = fdt_path_offset(fdt, symbol_path);
374 if (symbol_off < 0)
375 return symbol_off;
376
377 phandle = fdt_get_phandle(fdt, symbol_off);
378 if (!phandle)
379 return -FDT_ERR_NOTFOUND;
380
381 fixup_off = fdt_path_offset_namelen(fdto, path, path_len);
382 if (fixup_off == -FDT_ERR_NOTFOUND)
383 return -FDT_ERR_BADOVERLAY;
384 if (fixup_off < 0)
385 return fixup_off;
386
387 phandle_prop = cpu_to_fdt32(phandle);
388 return fdt_setprop_inplace_namelen_partial(fdto, fixup_off,
389 name, name_len, poffset,
390 &phandle_prop,
391 sizeof(phandle_prop));
392 };
393
394 /**
395 * overlay_fixup_phandle - Set an overlay phandle to the base one
396 * @fdt: Base Device Tree blob
397 * @fdto: Device tree overlay blob
398 * @symbols_off: Node offset of the symbols node in the base device tree
399 * @property: Property offset in the overlay holding the list of fixups
400 *
401 * overlay_fixup_phandle() resolves all the overlay phandles pointed
402 * to in a __fixups__ property, and updates them to match the phandles
403 * in use in the base device tree.
404 *
405 * This is part of the device tree overlay application process, when
406 * you want all the phandles in the overlay to point to the actual
407 * base dt nodes.
408 *
409 * returns:
410 * 0 on success
411 * Negative error code on failure
412 */
overlay_fixup_phandle(void * fdt,void * fdto,int symbols_off,int property)413 static int overlay_fixup_phandle(void *fdt, void *fdto, int symbols_off,
414 int property)
415 {
416 const char *value;
417 const char *label;
418 int len;
419
420 value = fdt_getprop_by_offset(fdto, property,
421 &label, &len);
422 if (!value) {
423 if (len == -FDT_ERR_NOTFOUND)
424 return -FDT_ERR_INTERNAL;
425
426 return len;
427 }
428
429 do {
430 const char *path, *name, *fixup_end;
431 const char *fixup_str = value;
432 uint32_t path_len, name_len;
433 uint32_t fixup_len;
434 char *sep, *endptr;
435 int poffset, ret;
436
437 fixup_end = memchr(value, '\0', len);
438 if (!fixup_end)
439 return -FDT_ERR_BADOVERLAY;
440 fixup_len = fixup_end - fixup_str;
441
442 len -= fixup_len + 1;
443 value += fixup_len + 1;
444
445 path = fixup_str;
446 sep = memchr(fixup_str, ':', fixup_len);
447 if (!sep || *sep != ':')
448 return -FDT_ERR_BADOVERLAY;
449
450 path_len = sep - path;
451 if (path_len == (fixup_len - 1))
452 return -FDT_ERR_BADOVERLAY;
453
454 fixup_len -= path_len + 1;
455 name = sep + 1;
456 sep = memchr(name, ':', fixup_len);
457 if (!sep || *sep != ':')
458 return -FDT_ERR_BADOVERLAY;
459
460 name_len = sep - name;
461 if (!name_len)
462 return -FDT_ERR_BADOVERLAY;
463
464 poffset = strtoul(sep + 1, &endptr, 10);
465 if ((*endptr != '\0') || (endptr <= (sep + 1)))
466 return -FDT_ERR_BADOVERLAY;
467
468 ret = overlay_fixup_one_phandle(fdt, fdto, symbols_off,
469 path, path_len, name, name_len,
470 poffset, label);
471 if (ret)
472 return ret;
473 } while (len > 0);
474
475 return 0;
476 }
477
478 /**
479 * overlay_fixup_phandles - Resolve the overlay phandles to the base
480 * device tree
481 * @fdt: Base Device Tree blob
482 * @fdto: Device tree overlay blob
483 *
484 * overlay_fixup_phandles() resolves all the overlay phandles pointing
485 * to nodes in the base device tree.
486 *
487 * This is one of the steps of the device tree overlay application
488 * process, when you want all the phandles in the overlay to point to
489 * the actual base dt nodes.
490 *
491 * returns:
492 * 0 on success
493 * Negative error code on failure
494 */
overlay_fixup_phandles(void * fdt,void * fdto)495 static int overlay_fixup_phandles(void *fdt, void *fdto)
496 {
497 int fixups_off, symbols_off;
498 int property;
499
500 /* We can have overlays without any fixups */
501 fixups_off = fdt_path_offset(fdto, "/__fixups__");
502 if (fixups_off == -FDT_ERR_NOTFOUND)
503 return 0; /* nothing to do */
504 if (fixups_off < 0)
505 return fixups_off;
506
507 /* And base DTs without symbols */
508 symbols_off = fdt_path_offset(fdt, "/__symbols__");
509 if ((symbols_off < 0 && (symbols_off != -FDT_ERR_NOTFOUND)))
510 return symbols_off;
511
512 fdt_for_each_property_offset(property, fdto, fixups_off) {
513 int ret;
514
515 ret = overlay_fixup_phandle(fdt, fdto, symbols_off, property);
516 if (ret)
517 return ret;
518 }
519
520 return 0;
521 }
522
523 /**
524 * overlay_apply_node - Merges a node into the base device tree
525 * @fdt: Base Device Tree blob
526 * @target: Node offset in the base device tree to apply the fragment to
527 * @fdto: Device tree overlay blob
528 * @node: Node offset in the overlay holding the changes to merge
529 *
530 * overlay_apply_node() merges a node into a target base device tree
531 * node pointed.
532 *
533 * This is part of the final step in the device tree overlay
534 * application process, when all the phandles have been adjusted and
535 * resolved and you just have to merge overlay into the base device
536 * tree.
537 *
538 * returns:
539 * 0 on success
540 * Negative error code on failure
541 */
overlay_apply_node(void * fdt,int target,void * fdto,int node)542 static int overlay_apply_node(void *fdt, int target,
543 void *fdto, int node)
544 {
545 int property;
546 int subnode;
547
548 fdt_for_each_property_offset(property, fdto, node) {
549 const char *name;
550 const void *prop;
551 int prop_len;
552 int ret;
553
554 prop = fdt_getprop_by_offset(fdto, property, &name,
555 &prop_len);
556 if (prop_len == -FDT_ERR_NOTFOUND)
557 return -FDT_ERR_INTERNAL;
558 if (prop_len < 0)
559 return prop_len;
560
561 ret = fdt_setprop(fdt, target, name, prop, prop_len);
562 if (ret)
563 return ret;
564 }
565
566 fdt_for_each_subnode(subnode, fdto, node) {
567 const char *name = fdt_get_name(fdto, subnode, NULL);
568 int nnode;
569 int ret;
570
571 nnode = fdt_add_subnode(fdt, target, name);
572 if (nnode == -FDT_ERR_EXISTS) {
573 nnode = fdt_subnode_offset(fdt, target, name);
574 if (nnode == -FDT_ERR_NOTFOUND)
575 return -FDT_ERR_INTERNAL;
576 }
577
578 if (nnode < 0)
579 return nnode;
580
581 ret = overlay_apply_node(fdt, nnode, fdto, subnode);
582 if (ret)
583 return ret;
584 }
585
586 return 0;
587 }
588
589 /**
590 * overlay_merge - Merge an overlay into its base device tree
591 * @fdt: Base Device Tree blob
592 * @fdto: Device tree overlay blob
593 *
594 * overlay_merge() merges an overlay into its base device tree.
595 *
596 * This is the next to last step in the device tree overlay application
597 * process, when all the phandles have been adjusted and resolved and
598 * you just have to merge overlay into the base device tree.
599 *
600 * returns:
601 * 0 on success
602 * Negative error code on failure
603 */
overlay_merge(void * fdt,void * fdto)604 static int overlay_merge(void *fdt, void *fdto)
605 {
606 int fragment;
607
608 fdt_for_each_subnode(fragment, fdto, 0) {
609 int overlay;
610 int target;
611 int ret;
612
613 /*
614 * Each fragments will have an __overlay__ node. If
615 * they don't, it's not supposed to be merged
616 */
617 overlay = fdt_subnode_offset(fdto, fragment, "__overlay__");
618 if (overlay == -FDT_ERR_NOTFOUND)
619 continue;
620
621 if (overlay < 0)
622 return overlay;
623
624 target = fdt_overlay_target_offset(fdt, fdto, fragment, NULL);
625 if (target < 0)
626 return target;
627
628 ret = overlay_apply_node(fdt, target, fdto, overlay);
629 if (ret)
630 return ret;
631 }
632
633 return 0;
634 }
635
get_path_len(const void * fdt,int nodeoffset)636 static int get_path_len(const void *fdt, int nodeoffset)
637 {
638 int len = 0, namelen;
639 const char *name;
640
641 FDT_RO_PROBE(fdt);
642
643 for (;;) {
644 name = fdt_get_name(fdt, nodeoffset, &namelen);
645 if (!name)
646 return namelen;
647
648 /* root? we're done */
649 if (namelen == 0)
650 break;
651
652 nodeoffset = fdt_parent_offset(fdt, nodeoffset);
653 if (nodeoffset < 0)
654 return nodeoffset;
655 len += namelen + 1;
656 }
657
658 /* in case of root pretend it's "/" */
659 if (len == 0)
660 len++;
661 return len;
662 }
663
664 /**
665 * overlay_symbol_update - Update the symbols of base tree after a merge
666 * @fdt: Base Device Tree blob
667 * @fdto: Device tree overlay blob
668 *
669 * overlay_symbol_update() updates the symbols of the base tree with the
670 * symbols of the applied overlay
671 *
672 * This is the last step in the device tree overlay application
673 * process, allowing the reference of overlay symbols by subsequent
674 * overlay operations.
675 *
676 * returns:
677 * 0 on success
678 * Negative error code on failure
679 */
overlay_symbol_update(void * fdt,void * fdto)680 static int overlay_symbol_update(void *fdt, void *fdto)
681 {
682 int root_sym, ov_sym, prop, path_len, fragment, target;
683 int len, frag_name_len, ret, rel_path_len;
684 const char *s, *e;
685 const char *path;
686 const char *name;
687 const char *frag_name;
688 const char *rel_path;
689 const char *target_path;
690 char *buf;
691 void *p;
692
693 ov_sym = fdt_subnode_offset(fdto, 0, "__symbols__");
694
695 /* if no overlay symbols exist no problem */
696 if (ov_sym < 0)
697 return 0;
698
699 root_sym = fdt_subnode_offset(fdt, 0, "__symbols__");
700
701 /* it no root symbols exist we should create them */
702 if (root_sym == -FDT_ERR_NOTFOUND)
703 root_sym = fdt_add_subnode(fdt, 0, "__symbols__");
704
705 /* any error is fatal now */
706 if (root_sym < 0)
707 return root_sym;
708
709 /* iterate over each overlay symbol */
710 fdt_for_each_property_offset(prop, fdto, ov_sym) {
711 path = fdt_getprop_by_offset(fdto, prop, &name, &path_len);
712 if (!path)
713 return path_len;
714
715 /* verify it's a string property (terminated by a single \0) */
716 if (path_len < 1 || memchr(path, '\0', path_len) != &path[path_len - 1])
717 return -FDT_ERR_BADVALUE;
718
719 /* keep end marker to avoid strlen() */
720 e = path + path_len;
721
722 if (*path != '/')
723 return -FDT_ERR_BADVALUE;
724
725 /* get fragment name first */
726 s = strchr(path + 1, '/');
727 if (!s) {
728 /* Symbol refers to something that won't end
729 * up in the target tree */
730 continue;
731 }
732
733 frag_name = path + 1;
734 frag_name_len = s - path - 1;
735
736 /* verify format; safe since "s" lies in \0 terminated prop */
737 len = sizeof("/__overlay__/") - 1;
738 if ((e - s) > len && (memcmp(s, "/__overlay__/", len) == 0)) {
739 /* /<fragment-name>/__overlay__/<relative-subnode-path> */
740 rel_path = s + len;
741 rel_path_len = e - rel_path - 1;
742 } else if ((e - s) == len
743 && (memcmp(s, "/__overlay__", len - 1) == 0)) {
744 /* /<fragment-name>/__overlay__ */
745 rel_path = "";
746 rel_path_len = 0;
747 } else {
748 /* Symbol refers to something that won't end
749 * up in the target tree */
750 continue;
751 }
752
753 /* find the fragment index in which the symbol lies */
754 ret = fdt_subnode_offset_namelen(fdto, 0, frag_name,
755 frag_name_len);
756 /* not found? */
757 if (ret < 0)
758 return -FDT_ERR_BADOVERLAY;
759 fragment = ret;
760
761 /* an __overlay__ subnode must exist */
762 ret = fdt_subnode_offset(fdto, fragment, "__overlay__");
763 if (ret < 0)
764 return -FDT_ERR_BADOVERLAY;
765
766 /* get the target of the fragment */
767 ret = fdt_overlay_target_offset(fdt, fdto, fragment, &target_path);
768 if (ret < 0)
769 return ret;
770 target = ret;
771
772 /* if we have a target path use */
773 if (!target_path) {
774 ret = get_path_len(fdt, target);
775 if (ret < 0)
776 return ret;
777 len = ret;
778 } else {
779 len = strlen(target_path);
780 }
781
782 ret = fdt_setprop_placeholder(fdt, root_sym, name,
783 len + (len > 1) + rel_path_len + 1, &p);
784 if (ret < 0)
785 return ret;
786
787 if (!target_path) {
788 /* again in case setprop_placeholder changed it */
789 ret = fdt_overlay_target_offset(fdt, fdto, fragment, &target_path);
790 if (ret < 0)
791 return ret;
792 target = ret;
793 }
794
795 buf = p;
796 if (len > 1) { /* target is not root */
797 if (!target_path) {
798 ret = fdt_get_path(fdt, target, buf, len + 1);
799 if (ret < 0)
800 return ret;
801 } else
802 memcpy(buf, target_path, len + 1);
803
804 } else
805 len--;
806
807 buf[len] = '/';
808 memcpy(buf + len + 1, rel_path, rel_path_len);
809 buf[len + 1 + rel_path_len] = '\0';
810 }
811
812 return 0;
813 }
814
fdt_overlay_apply(void * fdt,void * fdto)815 int fdt_overlay_apply(void *fdt, void *fdto)
816 {
817 uint32_t delta;
818 int ret;
819
820 FDT_RO_PROBE(fdt);
821 FDT_RO_PROBE(fdto);
822
823 ret = fdt_find_max_phandle(fdt, &delta);
824 if (ret)
825 goto err;
826
827 ret = overlay_adjust_local_phandles(fdto, delta);
828 if (ret)
829 goto err;
830
831 ret = overlay_update_local_references(fdto, delta);
832 if (ret)
833 goto err;
834
835 ret = overlay_fixup_phandles(fdt, fdto);
836 if (ret)
837 goto err;
838
839 ret = overlay_merge(fdt, fdto);
840 if (ret)
841 goto err;
842
843 ret = overlay_symbol_update(fdt, fdto);
844 if (ret)
845 goto err;
846
847 /*
848 * The overlay has been damaged, erase its magic.
849 */
850 fdt_set_magic(fdto, ~0);
851
852 return 0;
853
854 err:
855 /*
856 * The overlay might have been damaged, erase its magic.
857 */
858 fdt_set_magic(fdto, ~0);
859
860 /*
861 * The base device tree might have been damaged, erase its
862 * magic.
863 */
864 fdt_set_magic(fdt, ~0);
865
866 return ret;
867 }
868
