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4201d057 RH |
1 | #include "libfdt_env.h" |
2 | ||
3 | #include <fdt.h> | |
4 | #include <libfdt.h> | |
5 | ||
6 | #include "libfdt_internal.h" | |
7 | ||
8 | /** | |
9 | * overlay_get_target_phandle - retrieves the target phandle of a fragment | |
10 | * @fdto: pointer to the device tree overlay blob | |
11 | * @fragment: node offset of the fragment in the overlay | |
12 | * | |
13 | * overlay_get_target_phandle() retrieves the target phandle of an | |
14 | * overlay fragment when that fragment uses a phandle (target | |
15 | * property) instead of a path (target-path property). | |
16 | * | |
17 | * returns: | |
18 | * the phandle pointed by the target property | |
19 | * 0, if the phandle was not found | |
20 | * -1, if the phandle was malformed | |
21 | */ | |
22 | static uint32_t overlay_get_target_phandle(const void *fdto, int fragment) | |
23 | { | |
24 | const fdt32_t *val; | |
25 | int len; | |
26 | ||
27 | val = fdt_getprop(fdto, fragment, "target", &len); | |
28 | if (!val) | |
29 | return 0; | |
30 | ||
31 | if ((len != sizeof(*val)) || (fdt32_to_cpu(*val) == (uint32_t)-1)) | |
32 | return (uint32_t)-1; | |
33 | ||
34 | return fdt32_to_cpu(*val); | |
35 | } | |
36 | ||
37 | /** | |
38 | * overlay_get_target - retrieves the offset of a fragment's target | |
39 | * @fdt: Base device tree blob | |
40 | * @fdto: Device tree overlay blob | |
41 | * @fragment: node offset of the fragment in the overlay | |
42 | * @pathp: pointer which receives the path of the target (or NULL) | |
43 | * | |
44 | * overlay_get_target() retrieves the target offset in the base | |
45 | * device tree of a fragment, no matter how the actual targetting is | |
46 | * done (through a phandle or a path) | |
47 | * | |
48 | * returns: | |
49 | * the targetted node offset in the base device tree | |
50 | * Negative error code on error | |
51 | */ | |
52 | static int overlay_get_target(const void *fdt, const void *fdto, | |
53 | int fragment, char const **pathp) | |
54 | { | |
55 | uint32_t phandle; | |
56 | const char *path = NULL; | |
57 | int path_len = 0, ret; | |
58 | ||
59 | /* Try first to do a phandle based lookup */ | |
60 | phandle = overlay_get_target_phandle(fdto, fragment); | |
61 | if (phandle == (uint32_t)-1) | |
62 | return -FDT_ERR_BADPHANDLE; | |
63 | ||
64 | /* no phandle, try path */ | |
65 | if (!phandle) { | |
66 | /* And then a path based lookup */ | |
67 | path = fdt_getprop(fdto, fragment, "target-path", &path_len); | |
68 | if (path) | |
69 | ret = fdt_path_offset(fdt, path); | |
70 | else | |
71 | ret = path_len; | |
72 | } else | |
73 | ret = fdt_node_offset_by_phandle(fdt, phandle); | |
74 | ||
75 | /* | |
76 | * If we haven't found either a target or a | |
77 | * target-path property in a node that contains a | |
78 | * __overlay__ subnode (we wouldn't be called | |
79 | * otherwise), consider it a improperly written | |
80 | * overlay | |
81 | */ | |
82 | if (ret < 0 && path_len == -FDT_ERR_NOTFOUND) | |
83 | ret = -FDT_ERR_BADOVERLAY; | |
84 | ||
85 | /* return on error */ | |
86 | if (ret < 0) | |
87 | return ret; | |
88 | ||
89 | /* return pointer to path (if available) */ | |
90 | if (pathp) | |
91 | *pathp = path ? path : NULL; | |
92 | ||
93 | return ret; | |
94 | } | |
95 | ||
96 | /** | |
97 | * overlay_phandle_add_offset - Increases a phandle by an offset | |
98 | * @fdt: Base device tree blob | |
99 | * @node: Device tree overlay blob | |
100 | * @name: Name of the property to modify (phandle or linux,phandle) | |
101 | * @delta: offset to apply | |
102 | * | |
103 | * overlay_phandle_add_offset() increments a node phandle by a given | |
104 | * offset. | |
105 | * | |
106 | * returns: | |
107 | * 0 on success. | |
108 | * Negative error code on error | |
109 | */ | |
110 | static int overlay_phandle_add_offset(void *fdt, int node, | |
111 | const char *name, uint32_t delta) | |
112 | { | |
113 | const fdt32_t *val; | |
114 | uint32_t adj_val; | |
115 | int len; | |
116 | ||
117 | val = fdt_getprop(fdt, node, name, &len); | |
118 | if (!val) | |
119 | return len; | |
120 | ||
121 | if (len != sizeof(*val)) | |
122 | return -FDT_ERR_BADPHANDLE; | |
123 | ||
124 | adj_val = fdt32_to_cpu(*val); | |
125 | if ((adj_val + delta) < adj_val) | |
126 | return -FDT_ERR_NOPHANDLES; | |
127 | ||
128 | adj_val += delta; | |
129 | if (adj_val == (uint32_t)-1) | |
130 | return -FDT_ERR_NOPHANDLES; | |
131 | ||
132 | return fdt_setprop_inplace_u32(fdt, node, name, adj_val); | |
133 | } | |
134 | ||
135 | /** | |
136 | * overlay_adjust_node_phandles - Offsets the phandles of a node | |
137 | * @fdto: Device tree overlay blob | |
138 | * @node: Offset of the node we want to adjust | |
139 | * @delta: Offset to shift the phandles of | |
140 | * | |
141 | * overlay_adjust_node_phandles() adds a constant to all the phandles | |
142 | * of a given node. This is mainly use as part of the overlay | |
143 | * application process, when we want to update all the overlay | |
144 | * phandles to not conflict with the overlays of the base device tree. | |
145 | * | |
146 | * returns: | |
147 | * 0 on success | |
148 | * Negative error code on failure | |
149 | */ | |
150 | static int overlay_adjust_node_phandles(void *fdto, int node, | |
151 | uint32_t delta) | |
152 | { | |
153 | int child; | |
154 | int ret; | |
155 | ||
156 | ret = overlay_phandle_add_offset(fdto, node, "phandle", delta); | |
157 | if (ret && ret != -FDT_ERR_NOTFOUND) | |
158 | return ret; | |
159 | ||
160 | ret = overlay_phandle_add_offset(fdto, node, "linux,phandle", delta); | |
161 | if (ret && ret != -FDT_ERR_NOTFOUND) | |
162 | return ret; | |
163 | ||
164 | fdt_for_each_subnode(child, fdto, node) { | |
165 | ret = overlay_adjust_node_phandles(fdto, child, delta); | |
166 | if (ret) | |
167 | return ret; | |
168 | } | |
169 | ||
170 | return 0; | |
171 | } | |
172 | ||
173 | /** | |
174 | * overlay_adjust_local_phandles - Adjust the phandles of a whole overlay | |
175 | * @fdto: Device tree overlay blob | |
176 | * @delta: Offset to shift the phandles of | |
177 | * | |
178 | * overlay_adjust_local_phandles() adds a constant to all the | |
179 | * phandles of an overlay. This is mainly use as part of the overlay | |
180 | * application process, when we want to update all the overlay | |
181 | * phandles to not conflict with the overlays of the base device tree. | |
182 | * | |
183 | * returns: | |
184 | * 0 on success | |
185 | * Negative error code on failure | |
186 | */ | |
187 | static int overlay_adjust_local_phandles(void *fdto, uint32_t delta) | |
188 | { | |
189 | /* | |
190 | * Start adjusting the phandles from the overlay root | |
191 | */ | |
192 | return overlay_adjust_node_phandles(fdto, 0, delta); | |
193 | } | |
194 | ||
195 | /** | |
196 | * overlay_update_local_node_references - Adjust the overlay references | |
197 | * @fdto: Device tree overlay blob | |
198 | * @tree_node: Node offset of the node to operate on | |
199 | * @fixup_node: Node offset of the matching local fixups node | |
200 | * @delta: Offset to shift the phandles of | |
201 | * | |
202 | * overlay_update_local_nodes_references() update the phandles | |
203 | * pointing to a node within the device tree overlay by adding a | |
204 | * constant delta. | |
205 | * | |
206 | * This is mainly used as part of a device tree application process, | |
207 | * where you want the device tree overlays phandles to not conflict | |
208 | * with the ones from the base device tree before merging them. | |
209 | * | |
210 | * returns: | |
211 | * 0 on success | |
212 | * Negative error code on failure | |
213 | */ | |
214 | static int overlay_update_local_node_references(void *fdto, | |
215 | int tree_node, | |
216 | int fixup_node, | |
217 | uint32_t delta) | |
218 | { | |
219 | int fixup_prop; | |
220 | int fixup_child; | |
221 | int ret; | |
222 | ||
223 | fdt_for_each_property_offset(fixup_prop, fdto, fixup_node) { | |
224 | const fdt32_t *fixup_val; | |
225 | const char *tree_val; | |
226 | const char *name; | |
227 | int fixup_len; | |
228 | int tree_len; | |
229 | int i; | |
230 | ||
231 | fixup_val = fdt_getprop_by_offset(fdto, fixup_prop, | |
232 | &name, &fixup_len); | |
233 | if (!fixup_val) | |
234 | return fixup_len; | |
235 | ||
236 | if (fixup_len % sizeof(uint32_t)) | |
237 | return -FDT_ERR_BADOVERLAY; | |
238 | ||
239 | tree_val = fdt_getprop(fdto, tree_node, name, &tree_len); | |
240 | if (!tree_val) { | |
241 | if (tree_len == -FDT_ERR_NOTFOUND) | |
242 | return -FDT_ERR_BADOVERLAY; | |
243 | ||
244 | return tree_len; | |
245 | } | |
246 | ||
247 | for (i = 0; i < (fixup_len / sizeof(uint32_t)); i++) { | |
248 | fdt32_t adj_val; | |
249 | uint32_t poffset; | |
250 | ||
251 | poffset = fdt32_to_cpu(fixup_val[i]); | |
252 | ||
253 | /* | |
254 | * phandles to fixup can be unaligned. | |
255 | * | |
256 | * Use a memcpy for the architectures that do | |
257 | * not support unaligned accesses. | |
258 | */ | |
259 | memcpy(&adj_val, tree_val + poffset, sizeof(adj_val)); | |
260 | ||
261 | adj_val = cpu_to_fdt32(fdt32_to_cpu(adj_val) + delta); | |
262 | ||
263 | ret = fdt_setprop_inplace_namelen_partial(fdto, | |
264 | tree_node, | |
265 | name, | |
266 | strlen(name), | |
267 | poffset, | |
268 | &adj_val, | |
269 | sizeof(adj_val)); | |
270 | if (ret == -FDT_ERR_NOSPACE) | |
271 | return -FDT_ERR_BADOVERLAY; | |
272 | ||
273 | if (ret) | |
274 | return ret; | |
275 | } | |
276 | } | |
277 | ||
278 | fdt_for_each_subnode(fixup_child, fdto, fixup_node) { | |
279 | const char *fixup_child_name = fdt_get_name(fdto, fixup_child, | |
280 | NULL); | |
281 | int tree_child; | |
282 | ||
283 | tree_child = fdt_subnode_offset(fdto, tree_node, | |
284 | fixup_child_name); | |
285 | if (tree_child == -FDT_ERR_NOTFOUND) | |
286 | return -FDT_ERR_BADOVERLAY; | |
287 | if (tree_child < 0) | |
288 | return tree_child; | |
289 | ||
290 | ret = overlay_update_local_node_references(fdto, | |
291 | tree_child, | |
292 | fixup_child, | |
293 | delta); | |
294 | if (ret) | |
295 | return ret; | |
296 | } | |
297 | ||
298 | return 0; | |
299 | } | |
300 | ||
301 | /** | |
302 | * overlay_update_local_references - Adjust the overlay references | |
303 | * @fdto: Device tree overlay blob | |
304 | * @delta: Offset to shift the phandles of | |
305 | * | |
306 | * overlay_update_local_references() update all the phandles pointing | |
307 | * to a node within the device tree overlay by adding a constant | |
308 | * delta to not conflict with the base overlay. | |
309 | * | |
310 | * This is mainly used as part of a device tree application process, | |
311 | * where you want the device tree overlays phandles to not conflict | |
312 | * with the ones from the base device tree before merging them. | |
313 | * | |
314 | * returns: | |
315 | * 0 on success | |
316 | * Negative error code on failure | |
317 | */ | |
318 | static int overlay_update_local_references(void *fdto, uint32_t delta) | |
319 | { | |
320 | int fixups; | |
321 | ||
322 | fixups = fdt_path_offset(fdto, "/__local_fixups__"); | |
323 | if (fixups < 0) { | |
324 | /* There's no local phandles to adjust, bail out */ | |
325 | if (fixups == -FDT_ERR_NOTFOUND) | |
326 | return 0; | |
327 | ||
328 | return fixups; | |
329 | } | |
330 | ||
331 | /* | |
332 | * Update our local references from the root of the tree | |
333 | */ | |
334 | return overlay_update_local_node_references(fdto, 0, fixups, | |
335 | delta); | |
336 | } | |
337 | ||
338 | /** | |
339 | * overlay_fixup_one_phandle - Set an overlay phandle to the base one | |
340 | * @fdt: Base Device Tree blob | |
341 | * @fdto: Device tree overlay blob | |
342 | * @symbols_off: Node offset of the symbols node in the base device tree | |
343 | * @path: Path to a node holding a phandle in the overlay | |
344 | * @path_len: number of path characters to consider | |
345 | * @name: Name of the property holding the phandle reference in the overlay | |
346 | * @name_len: number of name characters to consider | |
347 | * @poffset: Offset within the overlay property where the phandle is stored | |
348 | * @label: Label of the node referenced by the phandle | |
349 | * | |
350 | * overlay_fixup_one_phandle() resolves an overlay phandle pointing to | |
351 | * a node in the base device tree. | |
352 | * | |
353 | * This is part of the device tree overlay application process, when | |
354 | * you want all the phandles in the overlay to point to the actual | |
355 | * base dt nodes. | |
356 | * | |
357 | * returns: | |
358 | * 0 on success | |
359 | * Negative error code on failure | |
360 | */ | |
361 | static int overlay_fixup_one_phandle(void *fdt, void *fdto, | |
362 | int symbols_off, | |
363 | const char *path, uint32_t path_len, | |
364 | const char *name, uint32_t name_len, | |
365 | int poffset, const char *label) | |
366 | { | |
367 | const char *symbol_path; | |
368 | uint32_t phandle; | |
369 | fdt32_t phandle_prop; | |
370 | int symbol_off, fixup_off; | |
371 | int prop_len; | |
372 | ||
373 | if (symbols_off < 0) | |
374 | return symbols_off; | |
375 | ||
376 | symbol_path = fdt_getprop(fdt, symbols_off, label, | |
377 | &prop_len); | |
378 | if (!symbol_path) | |
379 | return prop_len; | |
380 | ||
381 | symbol_off = fdt_path_offset(fdt, symbol_path); | |
382 | if (symbol_off < 0) | |
383 | return symbol_off; | |
384 | ||
385 | phandle = fdt_get_phandle(fdt, symbol_off); | |
386 | if (!phandle) | |
387 | return -FDT_ERR_NOTFOUND; | |
388 | ||
389 | fixup_off = fdt_path_offset_namelen(fdto, path, path_len); | |
390 | if (fixup_off == -FDT_ERR_NOTFOUND) | |
391 | return -FDT_ERR_BADOVERLAY; | |
392 | if (fixup_off < 0) | |
393 | return fixup_off; | |
394 | ||
395 | phandle_prop = cpu_to_fdt32(phandle); | |
396 | return fdt_setprop_inplace_namelen_partial(fdto, fixup_off, | |
397 | name, name_len, poffset, | |
398 | &phandle_prop, | |
399 | sizeof(phandle_prop)); | |
400 | }; | |
401 | ||
402 | /** | |
403 | * overlay_fixup_phandle - Set an overlay phandle to the base one | |
404 | * @fdt: Base Device Tree blob | |
405 | * @fdto: Device tree overlay blob | |
406 | * @symbols_off: Node offset of the symbols node in the base device tree | |
407 | * @property: Property offset in the overlay holding the list of fixups | |
408 | * | |
409 | * overlay_fixup_phandle() resolves all the overlay phandles pointed | |
410 | * to in a __fixups__ property, and updates them to match the phandles | |
411 | * in use in the base device tree. | |
412 | * | |
413 | * This is part of the device tree overlay application process, when | |
414 | * you want all the phandles in the overlay to point to the actual | |
415 | * base dt nodes. | |
416 | * | |
417 | * returns: | |
418 | * 0 on success | |
419 | * Negative error code on failure | |
420 | */ | |
421 | static int overlay_fixup_phandle(void *fdt, void *fdto, int symbols_off, | |
422 | int property) | |
423 | { | |
424 | const char *value; | |
425 | const char *label; | |
426 | int len; | |
427 | ||
428 | value = fdt_getprop_by_offset(fdto, property, | |
429 | &label, &len); | |
430 | if (!value) { | |
431 | if (len == -FDT_ERR_NOTFOUND) | |
432 | return -FDT_ERR_INTERNAL; | |
433 | ||
434 | return len; | |
435 | } | |
436 | ||
437 | do { | |
438 | const char *path, *name, *fixup_end; | |
439 | const char *fixup_str = value; | |
440 | uint32_t path_len, name_len; | |
441 | uint32_t fixup_len; | |
442 | char *sep, *endptr; | |
443 | int poffset, ret; | |
444 | ||
445 | fixup_end = memchr(value, '\0', len); | |
446 | if (!fixup_end) | |
447 | return -FDT_ERR_BADOVERLAY; | |
448 | fixup_len = fixup_end - fixup_str; | |
449 | ||
450 | len -= fixup_len + 1; | |
451 | value += fixup_len + 1; | |
452 | ||
453 | path = fixup_str; | |
454 | sep = memchr(fixup_str, ':', fixup_len); | |
455 | if (!sep || *sep != ':') | |
456 | return -FDT_ERR_BADOVERLAY; | |
457 | ||
458 | path_len = sep - path; | |
459 | if (path_len == (fixup_len - 1)) | |
460 | return -FDT_ERR_BADOVERLAY; | |
461 | ||
462 | fixup_len -= path_len + 1; | |
463 | name = sep + 1; | |
464 | sep = memchr(name, ':', fixup_len); | |
465 | if (!sep || *sep != ':') | |
466 | return -FDT_ERR_BADOVERLAY; | |
467 | ||
468 | name_len = sep - name; | |
469 | if (!name_len) | |
470 | return -FDT_ERR_BADOVERLAY; | |
471 | ||
472 | poffset = strtoul(sep + 1, &endptr, 10); | |
473 | if ((*endptr != '\0') || (endptr <= (sep + 1))) | |
474 | return -FDT_ERR_BADOVERLAY; | |
475 | ||
476 | ret = overlay_fixup_one_phandle(fdt, fdto, symbols_off, | |
477 | path, path_len, name, name_len, | |
478 | poffset, label); | |
479 | if (ret) | |
480 | return ret; | |
481 | } while (len > 0); | |
482 | ||
483 | return 0; | |
484 | } | |
485 | ||
486 | /** | |
487 | * overlay_fixup_phandles - Resolve the overlay phandles to the base | |
488 | * device tree | |
489 | * @fdt: Base Device Tree blob | |
490 | * @fdto: Device tree overlay blob | |
491 | * | |
492 | * overlay_fixup_phandles() resolves all the overlay phandles pointing | |
493 | * to nodes in the base device tree. | |
494 | * | |
495 | * This is one of the steps of the device tree overlay application | |
496 | * process, when you want all the phandles in the overlay to point to | |
497 | * the actual base dt nodes. | |
498 | * | |
499 | * returns: | |
500 | * 0 on success | |
501 | * Negative error code on failure | |
502 | */ | |
503 | static int overlay_fixup_phandles(void *fdt, void *fdto) | |
504 | { | |
505 | int fixups_off, symbols_off; | |
506 | int property; | |
507 | ||
508 | /* We can have overlays without any fixups */ | |
509 | fixups_off = fdt_path_offset(fdto, "/__fixups__"); | |
510 | if (fixups_off == -FDT_ERR_NOTFOUND) | |
511 | return 0; /* nothing to do */ | |
512 | if (fixups_off < 0) | |
513 | return fixups_off; | |
514 | ||
515 | /* And base DTs without symbols */ | |
516 | symbols_off = fdt_path_offset(fdt, "/__symbols__"); | |
517 | if ((symbols_off < 0 && (symbols_off != -FDT_ERR_NOTFOUND))) | |
518 | return symbols_off; | |
519 | ||
520 | fdt_for_each_property_offset(property, fdto, fixups_off) { | |
521 | int ret; | |
522 | ||
523 | ret = overlay_fixup_phandle(fdt, fdto, symbols_off, property); | |
524 | if (ret) | |
525 | return ret; | |
526 | } | |
527 | ||
528 | return 0; | |
529 | } | |
530 | ||
531 | /** | |
532 | * overlay_apply_node - Merges a node into the base device tree | |
533 | * @fdt: Base Device Tree blob | |
534 | * @target: Node offset in the base device tree to apply the fragment to | |
535 | * @fdto: Device tree overlay blob | |
536 | * @node: Node offset in the overlay holding the changes to merge | |
537 | * | |
538 | * overlay_apply_node() merges a node into a target base device tree | |
539 | * node pointed. | |
540 | * | |
541 | * This is part of the final step in the device tree overlay | |
542 | * application process, when all the phandles have been adjusted and | |
543 | * resolved and you just have to merge overlay into the base device | |
544 | * tree. | |
545 | * | |
546 | * returns: | |
547 | * 0 on success | |
548 | * Negative error code on failure | |
549 | */ | |
550 | static int overlay_apply_node(void *fdt, int target, | |
551 | void *fdto, int node) | |
552 | { | |
553 | int property; | |
554 | int subnode; | |
555 | ||
556 | fdt_for_each_property_offset(property, fdto, node) { | |
557 | const char *name; | |
558 | const void *prop; | |
559 | int prop_len; | |
560 | int ret; | |
561 | ||
562 | prop = fdt_getprop_by_offset(fdto, property, &name, | |
563 | &prop_len); | |
564 | if (prop_len == -FDT_ERR_NOTFOUND) | |
565 | return -FDT_ERR_INTERNAL; | |
566 | if (prop_len < 0) | |
567 | return prop_len; | |
568 | ||
569 | ret = fdt_setprop(fdt, target, name, prop, prop_len); | |
570 | if (ret) | |
571 | return ret; | |
572 | } | |
573 | ||
574 | fdt_for_each_subnode(subnode, fdto, node) { | |
575 | const char *name = fdt_get_name(fdto, subnode, NULL); | |
576 | int nnode; | |
577 | int ret; | |
578 | ||
579 | nnode = fdt_add_subnode(fdt, target, name); | |
580 | if (nnode == -FDT_ERR_EXISTS) { | |
581 | nnode = fdt_subnode_offset(fdt, target, name); | |
582 | if (nnode == -FDT_ERR_NOTFOUND) | |
583 | return -FDT_ERR_INTERNAL; | |
584 | } | |
585 | ||
586 | if (nnode < 0) | |
587 | return nnode; | |
588 | ||
589 | ret = overlay_apply_node(fdt, nnode, fdto, subnode); | |
590 | if (ret) | |
591 | return ret; | |
592 | } | |
593 | ||
594 | return 0; | |
595 | } | |
596 | ||
597 | /** | |
598 | * overlay_merge - Merge an overlay into its base device tree | |
599 | * @fdt: Base Device Tree blob | |
600 | * @fdto: Device tree overlay blob | |
601 | * | |
602 | * overlay_merge() merges an overlay into its base device tree. | |
603 | * | |
604 | * This is the next to last step in the device tree overlay application | |
605 | * process, when all the phandles have been adjusted and resolved and | |
606 | * you just have to merge overlay into the base device tree. | |
607 | * | |
608 | * returns: | |
609 | * 0 on success | |
610 | * Negative error code on failure | |
611 | */ | |
612 | static int overlay_merge(void *fdt, void *fdto) | |
613 | { | |
614 | int fragment; | |
615 | ||
616 | fdt_for_each_subnode(fragment, fdto, 0) { | |
617 | int overlay; | |
618 | int target; | |
619 | int ret; | |
620 | ||
621 | /* | |
622 | * Each fragments will have an __overlay__ node. If | |
623 | * they don't, it's not supposed to be merged | |
624 | */ | |
625 | overlay = fdt_subnode_offset(fdto, fragment, "__overlay__"); | |
626 | if (overlay == -FDT_ERR_NOTFOUND) | |
627 | continue; | |
628 | ||
629 | if (overlay < 0) | |
630 | return overlay; | |
631 | ||
632 | target = overlay_get_target(fdt, fdto, fragment, NULL); | |
633 | if (target < 0) | |
634 | return target; | |
635 | ||
636 | ret = overlay_apply_node(fdt, target, fdto, overlay); | |
637 | if (ret) | |
638 | return ret; | |
639 | } | |
640 | ||
641 | return 0; | |
642 | } | |
643 | ||
644 | static int get_path_len(const void *fdt, int nodeoffset) | |
645 | { | |
646 | int len = 0, namelen; | |
647 | const char *name; | |
648 | ||
649 | FDT_CHECK_HEADER(fdt); | |
650 | ||
651 | for (;;) { | |
652 | name = fdt_get_name(fdt, nodeoffset, &namelen); | |
653 | if (!name) | |
654 | return namelen; | |
655 | ||
656 | /* root? we're done */ | |
657 | if (namelen == 0) | |
658 | break; | |
659 | ||
660 | nodeoffset = fdt_parent_offset(fdt, nodeoffset); | |
661 | if (nodeoffset < 0) | |
662 | return nodeoffset; | |
663 | len += namelen + 1; | |
664 | } | |
665 | ||
666 | /* in case of root pretend it's "/" */ | |
667 | if (len == 0) | |
668 | len++; | |
669 | return len; | |
670 | } | |
671 | ||
672 | /** | |
673 | * overlay_symbol_update - Update the symbols of base tree after a merge | |
674 | * @fdt: Base Device Tree blob | |
675 | * @fdto: Device tree overlay blob | |
676 | * | |
677 | * overlay_symbol_update() updates the symbols of the base tree with the | |
678 | * symbols of the applied overlay | |
679 | * | |
680 | * This is the last step in the device tree overlay application | |
681 | * process, allowing the reference of overlay symbols by subsequent | |
682 | * overlay operations. | |
683 | * | |
684 | * returns: | |
685 | * 0 on success | |
686 | * Negative error code on failure | |
687 | */ | |
688 | static int overlay_symbol_update(void *fdt, void *fdto) | |
689 | { | |
690 | int root_sym, ov_sym, prop, path_len, fragment, target; | |
691 | int len, frag_name_len, ret, rel_path_len; | |
692 | const char *s, *e; | |
693 | const char *path; | |
694 | const char *name; | |
695 | const char *frag_name; | |
696 | const char *rel_path; | |
697 | const char *target_path; | |
698 | char *buf; | |
699 | void *p; | |
700 | ||
701 | ov_sym = fdt_subnode_offset(fdto, 0, "__symbols__"); | |
702 | ||
703 | /* if no overlay symbols exist no problem */ | |
704 | if (ov_sym < 0) | |
705 | return 0; | |
706 | ||
707 | root_sym = fdt_subnode_offset(fdt, 0, "__symbols__"); | |
708 | ||
709 | /* it no root symbols exist we should create them */ | |
710 | if (root_sym == -FDT_ERR_NOTFOUND) | |
711 | root_sym = fdt_add_subnode(fdt, 0, "__symbols__"); | |
712 | ||
713 | /* any error is fatal now */ | |
714 | if (root_sym < 0) | |
715 | return root_sym; | |
716 | ||
717 | /* iterate over each overlay symbol */ | |
718 | fdt_for_each_property_offset(prop, fdto, ov_sym) { | |
719 | path = fdt_getprop_by_offset(fdto, prop, &name, &path_len); | |
720 | if (!path) | |
721 | return path_len; | |
722 | ||
723 | /* verify it's a string property (terminated by a single \0) */ | |
724 | if (path_len < 1 || memchr(path, '\0', path_len) != &path[path_len - 1]) | |
725 | return -FDT_ERR_BADVALUE; | |
726 | ||
727 | /* keep end marker to avoid strlen() */ | |
728 | e = path + path_len; | |
729 | ||
730 | /* format: /<fragment-name>/__overlay__/<relative-subnode-path> */ | |
731 | ||
732 | if (*path != '/') | |
733 | return -FDT_ERR_BADVALUE; | |
734 | ||
735 | /* get fragment name first */ | |
736 | s = strchr(path + 1, '/'); | |
737 | if (!s) | |
738 | return -FDT_ERR_BADOVERLAY; | |
739 | ||
740 | frag_name = path + 1; | |
741 | frag_name_len = s - path - 1; | |
742 | ||
743 | /* verify format; safe since "s" lies in \0 terminated prop */ | |
744 | len = sizeof("/__overlay__/") - 1; | |
745 | if ((e - s) < len || memcmp(s, "/__overlay__/", len)) | |
746 | return -FDT_ERR_BADOVERLAY; | |
747 | ||
748 | rel_path = s + len; | |
749 | rel_path_len = e - rel_path; | |
750 | ||
751 | /* find the fragment index in which the symbol lies */ | |
752 | ret = fdt_subnode_offset_namelen(fdto, 0, frag_name, | |
753 | frag_name_len); | |
754 | /* not found? */ | |
755 | if (ret < 0) | |
756 | return -FDT_ERR_BADOVERLAY; | |
757 | fragment = ret; | |
758 | ||
759 | /* an __overlay__ subnode must exist */ | |
760 | ret = fdt_subnode_offset(fdto, fragment, "__overlay__"); | |
761 | if (ret < 0) | |
762 | return -FDT_ERR_BADOVERLAY; | |
763 | ||
764 | /* get the target of the fragment */ | |
765 | ret = overlay_get_target(fdt, fdto, fragment, &target_path); | |
766 | if (ret < 0) | |
767 | return ret; | |
768 | target = ret; | |
769 | ||
770 | /* if we have a target path use */ | |
771 | if (!target_path) { | |
772 | ret = get_path_len(fdt, target); | |
773 | if (ret < 0) | |
774 | return ret; | |
775 | len = ret; | |
776 | } else { | |
777 | len = strlen(target_path); | |
778 | } | |
779 | ||
780 | ret = fdt_setprop_placeholder(fdt, root_sym, name, | |
781 | len + (len > 1) + rel_path_len + 1, &p); | |
782 | if (ret < 0) | |
783 | return ret; | |
784 | ||
785 | if (!target_path) { | |
786 | /* again in case setprop_placeholder changed it */ | |
787 | ret = overlay_get_target(fdt, fdto, fragment, &target_path); | |
788 | if (ret < 0) | |
789 | return ret; | |
790 | target = ret; | |
791 | } | |
792 | ||
793 | buf = p; | |
794 | if (len > 1) { /* target is not root */ | |
795 | if (!target_path) { | |
796 | ret = fdt_get_path(fdt, target, buf, len + 1); | |
797 | if (ret < 0) | |
798 | return ret; | |
799 | } else | |
800 | memcpy(buf, target_path, len + 1); | |
801 | ||
802 | } else | |
803 | len--; | |
804 | ||
805 | buf[len] = '/'; | |
806 | memcpy(buf + len + 1, rel_path, rel_path_len); | |
807 | buf[len + 1 + rel_path_len] = '\0'; | |
808 | } | |
809 | ||
810 | return 0; | |
811 | } | |
812 | ||
813 | int fdt_overlay_apply(void *fdt, void *fdto) | |
814 | { | |
815 | uint32_t delta = fdt_get_max_phandle(fdt); | |
816 | int ret; | |
817 | ||
818 | FDT_CHECK_HEADER(fdt); | |
819 | FDT_CHECK_HEADER(fdto); | |
820 | ||
821 | ret = overlay_adjust_local_phandles(fdto, delta); | |
822 | if (ret) | |
823 | goto err; | |
824 | ||
825 | ret = overlay_update_local_references(fdto, delta); | |
826 | if (ret) | |
827 | goto err; | |
828 | ||
829 | ret = overlay_fixup_phandles(fdt, fdto); | |
830 | if (ret) | |
831 | goto err; | |
832 | ||
833 | ret = overlay_merge(fdt, fdto); | |
834 | if (ret) | |
835 | goto err; | |
836 | ||
837 | ret = overlay_symbol_update(fdt, fdto); | |
838 | if (ret) | |
839 | goto err; | |
840 | ||
841 | /* | |
842 | * The overlay has been damaged, erase its magic. | |
843 | */ | |
844 | fdt_set_magic(fdto, ~0); | |
845 | ||
846 | return 0; | |
847 | ||
848 | err: | |
849 | /* | |
850 | * The overlay might have been damaged, erase its magic. | |
851 | */ | |
852 | fdt_set_magic(fdto, ~0); | |
853 | ||
854 | /* | |
855 | * The base device tree might have been damaged, erase its | |
856 | * magic. | |
857 | */ | |
858 | fdt_set_magic(fdt, ~0); | |
859 | ||
860 | return ret; | |
861 | } |