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f0921f50 | 1 | // SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause) |
db405d19 RH |
2 | /* |
3 | * libfdt - Flat Device Tree manipulation | |
4 | * Copyright (C) 2016 Free Electrons | |
5 | * Copyright (C) 2016 NextThing Co. | |
db405d19 | 6 | */ |
999a78d5 MY |
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 | */ | |
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 | ||
43 | /** | |
44 | * overlay_get_target - retrieves the offset of a fragment's target | |
45 | * @fdt: Base device tree blob | |
46 | * @fdto: Device tree overlay blob | |
47 | * @fragment: node offset of the fragment in the overlay | |
48 | * @pathp: pointer which receives the path of the target (or NULL) | |
49 | * | |
50 | * overlay_get_target() retrieves the target offset in the base | |
f0921f50 | 51 | * device tree of a fragment, no matter how the actual targeting is |
999a78d5 MY |
52 | * done (through a phandle or a path) |
53 | * | |
54 | * returns: | |
f0921f50 | 55 | * the targeted node offset in the base device tree |
999a78d5 MY |
56 | * Negative error code on error |
57 | */ | |
58 | static int overlay_get_target(const void *fdt, const void *fdto, | |
59 | int fragment, char const **pathp) | |
60 | { | |
61 | uint32_t phandle; | |
62 | const char *path = NULL; | |
63 | int path_len = 0, ret; | |
64 | ||
65 | /* Try first to do a phandle based lookup */ | |
66 | phandle = overlay_get_target_phandle(fdto, fragment); | |
67 | if (phandle == (uint32_t)-1) | |
68 | return -FDT_ERR_BADPHANDLE; | |
69 | ||
70 | /* no phandle, try path */ | |
71 | if (!phandle) { | |
72 | /* And then a path based lookup */ | |
73 | path = fdt_getprop(fdto, fragment, "target-path", &path_len); | |
74 | if (path) | |
75 | ret = fdt_path_offset(fdt, path); | |
76 | else | |
77 | ret = path_len; | |
78 | } else | |
79 | ret = fdt_node_offset_by_phandle(fdt, phandle); | |
80 | ||
81 | /* | |
82 | * If we haven't found either a target or a | |
83 | * target-path property in a node that contains a | |
84 | * __overlay__ subnode (we wouldn't be called | |
85 | * otherwise), consider it a improperly written | |
86 | * overlay | |
87 | */ | |
88 | if (ret < 0 && path_len == -FDT_ERR_NOTFOUND) | |
89 | ret = -FDT_ERR_BADOVERLAY; | |
90 | ||
91 | /* return on error */ | |
92 | if (ret < 0) | |
93 | return ret; | |
94 | ||
95 | /* return pointer to path (if available) */ | |
96 | if (pathp) | |
97 | *pathp = path ? path : NULL; | |
98 | ||
99 | return ret; | |
100 | } | |
101 | ||
102 | /** | |
103 | * overlay_phandle_add_offset - Increases a phandle by an offset | |
104 | * @fdt: Base device tree blob | |
105 | * @node: Device tree overlay blob | |
106 | * @name: Name of the property to modify (phandle or linux,phandle) | |
107 | * @delta: offset to apply | |
108 | * | |
109 | * overlay_phandle_add_offset() increments a node phandle by a given | |
110 | * offset. | |
111 | * | |
112 | * returns: | |
113 | * 0 on success. | |
114 | * Negative error code on error | |
115 | */ | |
116 | static int overlay_phandle_add_offset(void *fdt, int node, | |
117 | const char *name, uint32_t delta) | |
118 | { | |
119 | const fdt32_t *val; | |
120 | uint32_t adj_val; | |
121 | int len; | |
122 | ||
123 | val = fdt_getprop(fdt, node, name, &len); | |
124 | if (!val) | |
125 | return len; | |
126 | ||
127 | if (len != sizeof(*val)) | |
128 | return -FDT_ERR_BADPHANDLE; | |
129 | ||
130 | adj_val = fdt32_to_cpu(*val); | |
131 | if ((adj_val + delta) < adj_val) | |
132 | return -FDT_ERR_NOPHANDLES; | |
133 | ||
134 | adj_val += delta; | |
135 | if (adj_val == (uint32_t)-1) | |
136 | return -FDT_ERR_NOPHANDLES; | |
137 | ||
138 | return fdt_setprop_inplace_u32(fdt, node, name, adj_val); | |
139 | } | |
140 | ||
141 | /** | |
142 | * overlay_adjust_node_phandles - Offsets the phandles of a node | |
143 | * @fdto: Device tree overlay blob | |
144 | * @node: Offset of the node we want to adjust | |
145 | * @delta: Offset to shift the phandles of | |
146 | * | |
147 | * overlay_adjust_node_phandles() adds a constant to all the phandles | |
148 | * of a given node. This is mainly use as part of the overlay | |
149 | * application process, when we want to update all the overlay | |
150 | * phandles to not conflict with the overlays of the base device tree. | |
151 | * | |
152 | * returns: | |
153 | * 0 on success | |
154 | * Negative error code on failure | |
155 | */ | |
156 | static int overlay_adjust_node_phandles(void *fdto, int node, | |
157 | uint32_t delta) | |
158 | { | |
159 | int child; | |
160 | int ret; | |
161 | ||
162 | ret = overlay_phandle_add_offset(fdto, node, "phandle", delta); | |
163 | if (ret && ret != -FDT_ERR_NOTFOUND) | |
164 | return ret; | |
165 | ||
166 | ret = overlay_phandle_add_offset(fdto, node, "linux,phandle", delta); | |
167 | if (ret && ret != -FDT_ERR_NOTFOUND) | |
168 | return ret; | |
169 | ||
170 | fdt_for_each_subnode(child, fdto, node) { | |
171 | ret = overlay_adjust_node_phandles(fdto, child, delta); | |
172 | if (ret) | |
173 | return ret; | |
174 | } | |
175 | ||
176 | return 0; | |
177 | } | |
178 | ||
179 | /** | |
180 | * overlay_adjust_local_phandles - Adjust the phandles of a whole overlay | |
181 | * @fdto: Device tree overlay blob | |
182 | * @delta: Offset to shift the phandles of | |
183 | * | |
184 | * overlay_adjust_local_phandles() adds a constant to all the | |
185 | * phandles of an overlay. This is mainly use as part of the overlay | |
186 | * application process, when we want to update all the overlay | |
187 | * phandles to not conflict with the overlays of the base device tree. | |
188 | * | |
189 | * returns: | |
190 | * 0 on success | |
191 | * Negative error code on failure | |
192 | */ | |
193 | static int overlay_adjust_local_phandles(void *fdto, uint32_t delta) | |
194 | { | |
195 | /* | |
196 | * Start adjusting the phandles from the overlay root | |
197 | */ | |
198 | return overlay_adjust_node_phandles(fdto, 0, delta); | |
199 | } | |
200 | ||
201 | /** | |
202 | * overlay_update_local_node_references - Adjust the overlay references | |
203 | * @fdto: Device tree overlay blob | |
204 | * @tree_node: Node offset of the node to operate on | |
205 | * @fixup_node: Node offset of the matching local fixups node | |
206 | * @delta: Offset to shift the phandles of | |
207 | * | |
208 | * overlay_update_local_nodes_references() update the phandles | |
209 | * pointing to a node within the device tree overlay by adding a | |
210 | * constant delta. | |
211 | * | |
212 | * This is mainly used as part of a device tree application process, | |
213 | * where you want the device tree overlays phandles to not conflict | |
214 | * with the ones from the base device tree before merging them. | |
215 | * | |
216 | * returns: | |
217 | * 0 on success | |
218 | * Negative error code on failure | |
219 | */ | |
220 | static int overlay_update_local_node_references(void *fdto, | |
221 | int tree_node, | |
222 | int fixup_node, | |
223 | uint32_t delta) | |
224 | { | |
225 | int fixup_prop; | |
226 | int fixup_child; | |
227 | int ret; | |
228 | ||
229 | fdt_for_each_property_offset(fixup_prop, fdto, fixup_node) { | |
230 | const fdt32_t *fixup_val; | |
231 | const char *tree_val; | |
232 | const char *name; | |
233 | int fixup_len; | |
234 | int tree_len; | |
235 | int i; | |
236 | ||
237 | fixup_val = fdt_getprop_by_offset(fdto, fixup_prop, | |
238 | &name, &fixup_len); | |
239 | if (!fixup_val) | |
240 | return fixup_len; | |
241 | ||
242 | if (fixup_len % sizeof(uint32_t)) | |
243 | return -FDT_ERR_BADOVERLAY; | |
244 | ||
245 | tree_val = fdt_getprop(fdto, tree_node, name, &tree_len); | |
246 | if (!tree_val) { | |
247 | if (tree_len == -FDT_ERR_NOTFOUND) | |
248 | return -FDT_ERR_BADOVERLAY; | |
249 | ||
250 | return tree_len; | |
251 | } | |
252 | ||
253 | for (i = 0; i < (fixup_len / sizeof(uint32_t)); i++) { | |
254 | fdt32_t adj_val; | |
255 | uint32_t poffset; | |
256 | ||
257 | poffset = fdt32_to_cpu(fixup_val[i]); | |
258 | ||
259 | /* | |
260 | * phandles to fixup can be unaligned. | |
261 | * | |
262 | * Use a memcpy for the architectures that do | |
263 | * not support unaligned accesses. | |
264 | */ | |
265 | memcpy(&adj_val, tree_val + poffset, sizeof(adj_val)); | |
266 | ||
267 | adj_val = cpu_to_fdt32(fdt32_to_cpu(adj_val) + delta); | |
268 | ||
269 | ret = fdt_setprop_inplace_namelen_partial(fdto, | |
270 | tree_node, | |
271 | name, | |
272 | strlen(name), | |
273 | poffset, | |
274 | &adj_val, | |
275 | sizeof(adj_val)); | |
276 | if (ret == -FDT_ERR_NOSPACE) | |
277 | return -FDT_ERR_BADOVERLAY; | |
278 | ||
279 | if (ret) | |
280 | return ret; | |
281 | } | |
282 | } | |
283 | ||
284 | fdt_for_each_subnode(fixup_child, fdto, fixup_node) { | |
285 | const char *fixup_child_name = fdt_get_name(fdto, fixup_child, | |
286 | NULL); | |
287 | int tree_child; | |
288 | ||
289 | tree_child = fdt_subnode_offset(fdto, tree_node, | |
290 | fixup_child_name); | |
291 | if (tree_child == -FDT_ERR_NOTFOUND) | |
292 | return -FDT_ERR_BADOVERLAY; | |
293 | if (tree_child < 0) | |
294 | return tree_child; | |
295 | ||
296 | ret = overlay_update_local_node_references(fdto, | |
297 | tree_child, | |
298 | fixup_child, | |
299 | delta); | |
300 | if (ret) | |
301 | return ret; | |
302 | } | |
303 | ||
304 | return 0; | |
305 | } | |
306 | ||
307 | /** | |
308 | * overlay_update_local_references - Adjust the overlay references | |
309 | * @fdto: Device tree overlay blob | |
310 | * @delta: Offset to shift the phandles of | |
311 | * | |
312 | * overlay_update_local_references() update all the phandles pointing | |
313 | * to a node within the device tree overlay by adding a constant | |
314 | * delta to not conflict with the base overlay. | |
315 | * | |
316 | * This is mainly used as part of a device tree application process, | |
317 | * where you want the device tree overlays phandles to not conflict | |
318 | * with the ones from the base device tree before merging them. | |
319 | * | |
320 | * returns: | |
321 | * 0 on success | |
322 | * Negative error code on failure | |
323 | */ | |
324 | static int overlay_update_local_references(void *fdto, uint32_t delta) | |
325 | { | |
326 | int fixups; | |
327 | ||
328 | fixups = fdt_path_offset(fdto, "/__local_fixups__"); | |
329 | if (fixups < 0) { | |
330 | /* There's no local phandles to adjust, bail out */ | |
331 | if (fixups == -FDT_ERR_NOTFOUND) | |
332 | return 0; | |
333 | ||
334 | return fixups; | |
335 | } | |
336 | ||
337 | /* | |
338 | * Update our local references from the root of the tree | |
339 | */ | |
340 | return overlay_update_local_node_references(fdto, 0, fixups, | |
341 | delta); | |
342 | } | |
343 | ||
344 | /** | |
345 | * overlay_fixup_one_phandle - Set an overlay phandle to the base one | |
346 | * @fdt: Base Device Tree blob | |
347 | * @fdto: Device tree overlay blob | |
348 | * @symbols_off: Node offset of the symbols node in the base device tree | |
349 | * @path: Path to a node holding a phandle in the overlay | |
350 | * @path_len: number of path characters to consider | |
351 | * @name: Name of the property holding the phandle reference in the overlay | |
352 | * @name_len: number of name characters to consider | |
353 | * @poffset: Offset within the overlay property where the phandle is stored | |
354 | * @label: Label of the node referenced by the phandle | |
355 | * | |
356 | * overlay_fixup_one_phandle() resolves an overlay phandle pointing to | |
357 | * a node in the base device tree. | |
358 | * | |
359 | * This is part of the device tree overlay application process, when | |
360 | * you want all the phandles in the overlay to point to the actual | |
361 | * base dt nodes. | |
362 | * | |
363 | * returns: | |
364 | * 0 on success | |
365 | * Negative error code on failure | |
366 | */ | |
367 | static int overlay_fixup_one_phandle(void *fdt, void *fdto, | |
368 | int symbols_off, | |
369 | const char *path, uint32_t path_len, | |
370 | const char *name, uint32_t name_len, | |
371 | int poffset, const char *label) | |
372 | { | |
373 | const char *symbol_path; | |
374 | uint32_t phandle; | |
375 | fdt32_t phandle_prop; | |
376 | int symbol_off, fixup_off; | |
377 | int prop_len; | |
378 | ||
379 | if (symbols_off < 0) | |
380 | return symbols_off; | |
381 | ||
382 | symbol_path = fdt_getprop(fdt, symbols_off, label, | |
383 | &prop_len); | |
384 | if (!symbol_path) | |
385 | return prop_len; | |
386 | ||
387 | symbol_off = fdt_path_offset(fdt, symbol_path); | |
388 | if (symbol_off < 0) | |
389 | return symbol_off; | |
390 | ||
391 | phandle = fdt_get_phandle(fdt, symbol_off); | |
392 | if (!phandle) | |
393 | return -FDT_ERR_NOTFOUND; | |
394 | ||
395 | fixup_off = fdt_path_offset_namelen(fdto, path, path_len); | |
396 | if (fixup_off == -FDT_ERR_NOTFOUND) | |
397 | return -FDT_ERR_BADOVERLAY; | |
398 | if (fixup_off < 0) | |
399 | return fixup_off; | |
400 | ||
401 | phandle_prop = cpu_to_fdt32(phandle); | |
402 | return fdt_setprop_inplace_namelen_partial(fdto, fixup_off, | |
403 | name, name_len, poffset, | |
404 | &phandle_prop, | |
405 | sizeof(phandle_prop)); | |
406 | }; | |
407 | ||
408 | /** | |
409 | * overlay_fixup_phandle - Set an overlay phandle to the base one | |
410 | * @fdt: Base Device Tree blob | |
411 | * @fdto: Device tree overlay blob | |
412 | * @symbols_off: Node offset of the symbols node in the base device tree | |
413 | * @property: Property offset in the overlay holding the list of fixups | |
414 | * | |
415 | * overlay_fixup_phandle() resolves all the overlay phandles pointed | |
416 | * to in a __fixups__ property, and updates them to match the phandles | |
417 | * in use in the base device tree. | |
418 | * | |
419 | * This is part of the device tree overlay application process, when | |
420 | * you want all the phandles in the overlay to point to the actual | |
421 | * base dt nodes. | |
422 | * | |
423 | * returns: | |
424 | * 0 on success | |
425 | * Negative error code on failure | |
426 | */ | |
427 | static int overlay_fixup_phandle(void *fdt, void *fdto, int symbols_off, | |
428 | int property) | |
429 | { | |
430 | const char *value; | |
431 | const char *label; | |
432 | int len; | |
433 | ||
434 | value = fdt_getprop_by_offset(fdto, property, | |
435 | &label, &len); | |
436 | if (!value) { | |
437 | if (len == -FDT_ERR_NOTFOUND) | |
438 | return -FDT_ERR_INTERNAL; | |
439 | ||
440 | return len; | |
441 | } | |
442 | ||
443 | do { | |
444 | const char *path, *name, *fixup_end; | |
445 | const char *fixup_str = value; | |
446 | uint32_t path_len, name_len; | |
447 | uint32_t fixup_len; | |
448 | char *sep, *endptr; | |
449 | int poffset, ret; | |
450 | ||
451 | fixup_end = memchr(value, '\0', len); | |
452 | if (!fixup_end) | |
453 | return -FDT_ERR_BADOVERLAY; | |
454 | fixup_len = fixup_end - fixup_str; | |
455 | ||
456 | len -= fixup_len + 1; | |
457 | value += fixup_len + 1; | |
458 | ||
459 | path = fixup_str; | |
460 | sep = memchr(fixup_str, ':', fixup_len); | |
461 | if (!sep || *sep != ':') | |
462 | return -FDT_ERR_BADOVERLAY; | |
463 | ||
464 | path_len = sep - path; | |
465 | if (path_len == (fixup_len - 1)) | |
466 | return -FDT_ERR_BADOVERLAY; | |
467 | ||
468 | fixup_len -= path_len + 1; | |
469 | name = sep + 1; | |
470 | sep = memchr(name, ':', fixup_len); | |
471 | if (!sep || *sep != ':') | |
472 | return -FDT_ERR_BADOVERLAY; | |
473 | ||
474 | name_len = sep - name; | |
475 | if (!name_len) | |
476 | return -FDT_ERR_BADOVERLAY; | |
477 | ||
478 | poffset = strtoul(sep + 1, &endptr, 10); | |
479 | if ((*endptr != '\0') || (endptr <= (sep + 1))) | |
480 | return -FDT_ERR_BADOVERLAY; | |
481 | ||
482 | ret = overlay_fixup_one_phandle(fdt, fdto, symbols_off, | |
483 | path, path_len, name, name_len, | |
484 | poffset, label); | |
485 | if (ret) | |
486 | return ret; | |
487 | } while (len > 0); | |
488 | ||
489 | return 0; | |
490 | } | |
491 | ||
492 | /** | |
493 | * overlay_fixup_phandles - Resolve the overlay phandles to the base | |
494 | * device tree | |
495 | * @fdt: Base Device Tree blob | |
496 | * @fdto: Device tree overlay blob | |
497 | * | |
498 | * overlay_fixup_phandles() resolves all the overlay phandles pointing | |
499 | * to nodes in the base device tree. | |
500 | * | |
501 | * This is one of the steps of the device tree overlay application | |
502 | * process, when you want all the phandles in the overlay to point to | |
503 | * the actual base dt nodes. | |
504 | * | |
505 | * returns: | |
506 | * 0 on success | |
507 | * Negative error code on failure | |
508 | */ | |
509 | static int overlay_fixup_phandles(void *fdt, void *fdto) | |
510 | { | |
511 | int fixups_off, symbols_off; | |
512 | int property; | |
513 | ||
514 | /* We can have overlays without any fixups */ | |
515 | fixups_off = fdt_path_offset(fdto, "/__fixups__"); | |
516 | if (fixups_off == -FDT_ERR_NOTFOUND) | |
517 | return 0; /* nothing to do */ | |
518 | if (fixups_off < 0) | |
519 | return fixups_off; | |
520 | ||
521 | /* And base DTs without symbols */ | |
522 | symbols_off = fdt_path_offset(fdt, "/__symbols__"); | |
523 | if ((symbols_off < 0 && (symbols_off != -FDT_ERR_NOTFOUND))) | |
524 | return symbols_off; | |
525 | ||
526 | fdt_for_each_property_offset(property, fdto, fixups_off) { | |
527 | int ret; | |
528 | ||
529 | ret = overlay_fixup_phandle(fdt, fdto, symbols_off, property); | |
530 | if (ret) | |
531 | return ret; | |
532 | } | |
533 | ||
534 | return 0; | |
535 | } | |
536 | ||
537 | /** | |
538 | * overlay_apply_node - Merges a node into the base device tree | |
539 | * @fdt: Base Device Tree blob | |
540 | * @target: Node offset in the base device tree to apply the fragment to | |
541 | * @fdto: Device tree overlay blob | |
542 | * @node: Node offset in the overlay holding the changes to merge | |
543 | * | |
544 | * overlay_apply_node() merges a node into a target base device tree | |
545 | * node pointed. | |
546 | * | |
547 | * This is part of the final step in the device tree overlay | |
548 | * application process, when all the phandles have been adjusted and | |
549 | * resolved and you just have to merge overlay into the base device | |
550 | * tree. | |
551 | * | |
552 | * returns: | |
553 | * 0 on success | |
554 | * Negative error code on failure | |
555 | */ | |
556 | static int overlay_apply_node(void *fdt, int target, | |
557 | void *fdto, int node) | |
558 | { | |
559 | int property; | |
560 | int subnode; | |
561 | ||
562 | fdt_for_each_property_offset(property, fdto, node) { | |
563 | const char *name; | |
564 | const void *prop; | |
565 | int prop_len; | |
566 | int ret; | |
567 | ||
568 | prop = fdt_getprop_by_offset(fdto, property, &name, | |
569 | &prop_len); | |
570 | if (prop_len == -FDT_ERR_NOTFOUND) | |
571 | return -FDT_ERR_INTERNAL; | |
572 | if (prop_len < 0) | |
573 | return prop_len; | |
574 | ||
575 | ret = fdt_setprop(fdt, target, name, prop, prop_len); | |
576 | if (ret) | |
577 | return ret; | |
578 | } | |
579 | ||
580 | fdt_for_each_subnode(subnode, fdto, node) { | |
581 | const char *name = fdt_get_name(fdto, subnode, NULL); | |
582 | int nnode; | |
583 | int ret; | |
584 | ||
585 | nnode = fdt_add_subnode(fdt, target, name); | |
586 | if (nnode == -FDT_ERR_EXISTS) { | |
587 | nnode = fdt_subnode_offset(fdt, target, name); | |
588 | if (nnode == -FDT_ERR_NOTFOUND) | |
589 | return -FDT_ERR_INTERNAL; | |
590 | } | |
591 | ||
592 | if (nnode < 0) | |
593 | return nnode; | |
594 | ||
595 | ret = overlay_apply_node(fdt, nnode, fdto, subnode); | |
596 | if (ret) | |
597 | return ret; | |
598 | } | |
599 | ||
600 | return 0; | |
601 | } | |
602 | ||
603 | /** | |
604 | * overlay_merge - Merge an overlay into its base device tree | |
605 | * @fdt: Base Device Tree blob | |
606 | * @fdto: Device tree overlay blob | |
607 | * | |
608 | * overlay_merge() merges an overlay into its base device tree. | |
609 | * | |
610 | * This is the next to last step in the device tree overlay application | |
611 | * process, when all the phandles have been adjusted and resolved and | |
612 | * you just have to merge overlay into the base device tree. | |
613 | * | |
614 | * returns: | |
615 | * 0 on success | |
616 | * Negative error code on failure | |
617 | */ | |
618 | static int overlay_merge(void *fdt, void *fdto) | |
619 | { | |
620 | int fragment; | |
621 | ||
622 | fdt_for_each_subnode(fragment, fdto, 0) { | |
623 | int overlay; | |
624 | int target; | |
625 | int ret; | |
626 | ||
627 | /* | |
628 | * Each fragments will have an __overlay__ node. If | |
629 | * they don't, it's not supposed to be merged | |
630 | */ | |
631 | overlay = fdt_subnode_offset(fdto, fragment, "__overlay__"); | |
632 | if (overlay == -FDT_ERR_NOTFOUND) | |
633 | continue; | |
634 | ||
635 | if (overlay < 0) | |
636 | return overlay; | |
637 | ||
638 | target = overlay_get_target(fdt, fdto, fragment, NULL); | |
639 | if (target < 0) | |
640 | return target; | |
641 | ||
642 | ret = overlay_apply_node(fdt, target, fdto, overlay); | |
643 | if (ret) | |
644 | return ret; | |
645 | } | |
646 | ||
647 | return 0; | |
648 | } | |
649 | ||
650 | static int get_path_len(const void *fdt, int nodeoffset) | |
651 | { | |
652 | int len = 0, namelen; | |
653 | const char *name; | |
654 | ||
f0921f50 | 655 | FDT_RO_PROBE(fdt); |
999a78d5 MY |
656 | |
657 | for (;;) { | |
658 | name = fdt_get_name(fdt, nodeoffset, &namelen); | |
659 | if (!name) | |
660 | return namelen; | |
661 | ||
662 | /* root? we're done */ | |
663 | if (namelen == 0) | |
664 | break; | |
665 | ||
666 | nodeoffset = fdt_parent_offset(fdt, nodeoffset); | |
667 | if (nodeoffset < 0) | |
668 | return nodeoffset; | |
669 | len += namelen + 1; | |
670 | } | |
671 | ||
672 | /* in case of root pretend it's "/" */ | |
673 | if (len == 0) | |
674 | len++; | |
675 | return len; | |
676 | } | |
677 | ||
678 | /** | |
679 | * overlay_symbol_update - Update the symbols of base tree after a merge | |
680 | * @fdt: Base Device Tree blob | |
681 | * @fdto: Device tree overlay blob | |
682 | * | |
683 | * overlay_symbol_update() updates the symbols of the base tree with the | |
684 | * symbols of the applied overlay | |
685 | * | |
686 | * This is the last step in the device tree overlay application | |
687 | * process, allowing the reference of overlay symbols by subsequent | |
688 | * overlay operations. | |
689 | * | |
690 | * returns: | |
691 | * 0 on success | |
692 | * Negative error code on failure | |
693 | */ | |
694 | static int overlay_symbol_update(void *fdt, void *fdto) | |
695 | { | |
696 | int root_sym, ov_sym, prop, path_len, fragment, target; | |
697 | int len, frag_name_len, ret, rel_path_len; | |
698 | const char *s, *e; | |
699 | const char *path; | |
700 | const char *name; | |
701 | const char *frag_name; | |
702 | const char *rel_path; | |
703 | const char *target_path; | |
704 | char *buf; | |
705 | void *p; | |
706 | ||
707 | ov_sym = fdt_subnode_offset(fdto, 0, "__symbols__"); | |
708 | ||
709 | /* if no overlay symbols exist no problem */ | |
710 | if (ov_sym < 0) | |
711 | return 0; | |
712 | ||
713 | root_sym = fdt_subnode_offset(fdt, 0, "__symbols__"); | |
714 | ||
715 | /* it no root symbols exist we should create them */ | |
716 | if (root_sym == -FDT_ERR_NOTFOUND) | |
717 | root_sym = fdt_add_subnode(fdt, 0, "__symbols__"); | |
718 | ||
719 | /* any error is fatal now */ | |
720 | if (root_sym < 0) | |
721 | return root_sym; | |
722 | ||
723 | /* iterate over each overlay symbol */ | |
724 | fdt_for_each_property_offset(prop, fdto, ov_sym) { | |
725 | path = fdt_getprop_by_offset(fdto, prop, &name, &path_len); | |
726 | if (!path) | |
727 | return path_len; | |
728 | ||
729 | /* verify it's a string property (terminated by a single \0) */ | |
730 | if (path_len < 1 || memchr(path, '\0', path_len) != &path[path_len - 1]) | |
731 | return -FDT_ERR_BADVALUE; | |
732 | ||
733 | /* keep end marker to avoid strlen() */ | |
734 | e = path + path_len; | |
735 | ||
999a78d5 MY |
736 | if (*path != '/') |
737 | return -FDT_ERR_BADVALUE; | |
738 | ||
739 | /* get fragment name first */ | |
740 | s = strchr(path + 1, '/'); | |
f0921f50 SG |
741 | if (!s) { |
742 | /* Symbol refers to something that won't end | |
743 | * up in the target tree */ | |
744 | continue; | |
745 | } | |
999a78d5 MY |
746 | |
747 | frag_name = path + 1; | |
748 | frag_name_len = s - path - 1; | |
749 | ||
750 | /* verify format; safe since "s" lies in \0 terminated prop */ | |
751 | len = sizeof("/__overlay__/") - 1; | |
f0921f50 SG |
752 | if ((e - s) > len && (memcmp(s, "/__overlay__/", len) == 0)) { |
753 | /* /<fragment-name>/__overlay__/<relative-subnode-path> */ | |
754 | rel_path = s + len; | |
755 | rel_path_len = e - rel_path; | |
756 | } else if ((e - s) == len | |
757 | && (memcmp(s, "/__overlay__", len - 1) == 0)) { | |
758 | /* /<fragment-name>/__overlay__ */ | |
759 | rel_path = ""; | |
760 | rel_path_len = 0; | |
761 | } else { | |
762 | /* Symbol refers to something that won't end | |
763 | * up in the target tree */ | |
764 | continue; | |
765 | } | |
999a78d5 MY |
766 | |
767 | /* find the fragment index in which the symbol lies */ | |
768 | ret = fdt_subnode_offset_namelen(fdto, 0, frag_name, | |
769 | frag_name_len); | |
770 | /* not found? */ | |
771 | if (ret < 0) | |
772 | return -FDT_ERR_BADOVERLAY; | |
773 | fragment = ret; | |
774 | ||
775 | /* an __overlay__ subnode must exist */ | |
776 | ret = fdt_subnode_offset(fdto, fragment, "__overlay__"); | |
777 | if (ret < 0) | |
778 | return -FDT_ERR_BADOVERLAY; | |
779 | ||
780 | /* get the target of the fragment */ | |
781 | ret = overlay_get_target(fdt, fdto, fragment, &target_path); | |
782 | if (ret < 0) | |
783 | return ret; | |
784 | target = ret; | |
785 | ||
786 | /* if we have a target path use */ | |
787 | if (!target_path) { | |
788 | ret = get_path_len(fdt, target); | |
789 | if (ret < 0) | |
790 | return ret; | |
791 | len = ret; | |
792 | } else { | |
793 | len = strlen(target_path); | |
794 | } | |
795 | ||
796 | ret = fdt_setprop_placeholder(fdt, root_sym, name, | |
797 | len + (len > 1) + rel_path_len + 1, &p); | |
798 | if (ret < 0) | |
799 | return ret; | |
800 | ||
801 | if (!target_path) { | |
802 | /* again in case setprop_placeholder changed it */ | |
803 | ret = overlay_get_target(fdt, fdto, fragment, &target_path); | |
804 | if (ret < 0) | |
805 | return ret; | |
806 | target = ret; | |
807 | } | |
808 | ||
809 | buf = p; | |
810 | if (len > 1) { /* target is not root */ | |
811 | if (!target_path) { | |
812 | ret = fdt_get_path(fdt, target, buf, len + 1); | |
813 | if (ret < 0) | |
814 | return ret; | |
815 | } else | |
816 | memcpy(buf, target_path, len + 1); | |
817 | ||
818 | } else | |
819 | len--; | |
820 | ||
821 | buf[len] = '/'; | |
822 | memcpy(buf + len + 1, rel_path, rel_path_len); | |
823 | buf[len + 1 + rel_path_len] = '\0'; | |
824 | } | |
825 | ||
826 | return 0; | |
827 | } | |
828 | ||
829 | int fdt_overlay_apply(void *fdt, void *fdto) | |
830 | { | |
f0921f50 | 831 | uint32_t delta; |
999a78d5 MY |
832 | int ret; |
833 | ||
f0921f50 SG |
834 | FDT_RO_PROBE(fdt); |
835 | FDT_RO_PROBE(fdto); | |
836 | ||
837 | ret = fdt_find_max_phandle(fdt, &delta); | |
838 | if (ret) | |
839 | goto err; | |
999a78d5 MY |
840 | |
841 | ret = overlay_adjust_local_phandles(fdto, delta); | |
842 | if (ret) | |
843 | goto err; | |
844 | ||
845 | ret = overlay_update_local_references(fdto, delta); | |
846 | if (ret) | |
847 | goto err; | |
848 | ||
849 | ret = overlay_fixup_phandles(fdt, fdto); | |
850 | if (ret) | |
851 | goto err; | |
852 | ||
853 | ret = overlay_merge(fdt, fdto); | |
854 | if (ret) | |
855 | goto err; | |
856 | ||
857 | ret = overlay_symbol_update(fdt, fdto); | |
858 | if (ret) | |
859 | goto err; | |
860 | ||
861 | /* | |
862 | * The overlay has been damaged, erase its magic. | |
863 | */ | |
864 | fdt_set_magic(fdto, ~0); | |
865 | ||
866 | return 0; | |
867 | ||
868 | err: | |
869 | /* | |
870 | * The overlay might have been damaged, erase its magic. | |
871 | */ | |
872 | fdt_set_magic(fdto, ~0); | |
873 | ||
874 | /* | |
875 | * The base device tree might have been damaged, erase its | |
876 | * magic. | |
877 | */ | |
878 | fdt_set_magic(fdt, ~0); | |
879 | ||
880 | return ret; | |
881 | } |