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 */ 28static 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 51 * device tree of a fragment, no matter how the actual targeting is 52 * done (through a phandle or a path) 53 * 54 * returns: 55 * the targeted node offset in the base device tree 56 * Negative error code on error 57 */ 58static 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 */ 116static 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 */ 156static 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 */ 193static 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 */ 220static 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 fixup_len /= sizeof(uint32_t); 245 246 tree_val = fdt_getprop(fdto, tree_node, name, &tree_len); 247 if (!tree_val) { 248 if (tree_len == -FDT_ERR_NOTFOUND) 249 return -FDT_ERR_BADOVERLAY; 250 251 return tree_len; 252 } 253 254 for (i = 0; i < fixup_len; i++) { 255 fdt32_t adj_val; 256 uint32_t poffset; 257 258 poffset = fdt32_to_cpu(fixup_val[i]); 259 260 /* 261 * phandles to fixup can be unaligned. 262 * 263 * Use a memcpy for the architectures that do 264 * not support unaligned accesses. 265 */ 266 memcpy(&adj_val, tree_val + poffset, sizeof(adj_val)); 267 268 adj_val = cpu_to_fdt32(fdt32_to_cpu(adj_val) + delta); 269 270 ret = fdt_setprop_inplace_namelen_partial(fdto, 271 tree_node, 272 name, 273 strlen(name), 274 poffset, 275 &adj_val, 276 sizeof(adj_val)); 277 if (ret == -FDT_ERR_NOSPACE) 278 return -FDT_ERR_BADOVERLAY; 279 280 if (ret) 281 return ret; 282 } 283 } 284 285 fdt_for_each_subnode(fixup_child, fdto, fixup_node) { 286 const char *fixup_child_name = fdt_get_name(fdto, fixup_child, 287 NULL); 288 int tree_child; 289 290 tree_child = fdt_subnode_offset(fdto, tree_node, 291 fixup_child_name); 292 if (tree_child == -FDT_ERR_NOTFOUND) 293 return -FDT_ERR_BADOVERLAY; 294 if (tree_child < 0) 295 return tree_child; 296 297 ret = overlay_update_local_node_references(fdto, 298 tree_child, 299 fixup_child, 300 delta); 301 if (ret) 302 return ret; 303 } 304 305 return 0; 306} 307 308/** 309 * overlay_update_local_references - Adjust the overlay references 310 * @fdto: Device tree overlay blob 311 * @delta: Offset to shift the phandles of 312 * 313 * overlay_update_local_references() update all the phandles pointing 314 * to a node within the device tree overlay by adding a constant 315 * delta to not conflict with the base overlay. 316 * 317 * This is mainly used as part of a device tree application process, 318 * where you want the device tree overlays phandles to not conflict 319 * with the ones from the base device tree before merging them. 320 * 321 * returns: 322 * 0 on success 323 * Negative error code on failure 324 */ 325static int overlay_update_local_references(void *fdto, uint32_t delta) 326{ 327 int fixups; 328 329 fixups = fdt_path_offset(fdto, "/__local_fixups__"); 330 if (fixups < 0) { 331 /* There's no local phandles to adjust, bail out */ 332 if (fixups == -FDT_ERR_NOTFOUND) 333 return 0; 334 335 return fixups; 336 } 337 338 /* 339 * Update our local references from the root of the tree 340 */ 341 return overlay_update_local_node_references(fdto, 0, fixups, 342 delta); 343} 344 345/** 346 * overlay_fixup_one_phandle - Set an overlay phandle to the base one 347 * @fdt: Base Device Tree blob 348 * @fdto: Device tree overlay blob 349 * @symbols_off: Node offset of the symbols node in the base device tree 350 * @path: Path to a node holding a phandle in the overlay 351 * @path_len: number of path characters to consider 352 * @name: Name of the property holding the phandle reference in the overlay 353 * @name_len: number of name characters to consider 354 * @poffset: Offset within the overlay property where the phandle is stored 355 * @label: Label of the node referenced by the phandle 356 * 357 * overlay_fixup_one_phandle() resolves an overlay phandle pointing to 358 * a node in the base device tree. 359 * 360 * This is part of the device tree overlay application process, when 361 * you want all the phandles in the overlay to point to the actual 362 * base dt nodes. 363 * 364 * returns: 365 * 0 on success 366 * Negative error code on failure 367 */ 368static int overlay_fixup_one_phandle(void *fdt, void *fdto, 369 int symbols_off, 370 const char *path, uint32_t path_len, 371 const char *name, uint32_t name_len, 372 int poffset, const char *label) 373{ 374 const char *symbol_path; 375 uint32_t phandle; 376 fdt32_t phandle_prop; 377 int symbol_off, fixup_off; 378 int prop_len; 379 380 if (symbols_off < 0) 381 return symbols_off; 382 383 symbol_path = fdt_getprop(fdt, symbols_off, label, 384 &prop_len); 385 if (!symbol_path) 386 return prop_len; 387 388 symbol_off = fdt_path_offset(fdt, symbol_path); 389 if (symbol_off < 0) 390 return symbol_off; 391 392 phandle = fdt_get_phandle(fdt, symbol_off); 393 if (!phandle) 394 return -FDT_ERR_NOTFOUND; 395 396 fixup_off = fdt_path_offset_namelen(fdto, path, path_len); 397 if (fixup_off == -FDT_ERR_NOTFOUND) 398 return -FDT_ERR_BADOVERLAY; 399 if (fixup_off < 0) 400 return fixup_off; 401 402 phandle_prop = cpu_to_fdt32(phandle); 403 return fdt_setprop_inplace_namelen_partial(fdto, fixup_off, 404 name, name_len, poffset, 405 &phandle_prop, 406 sizeof(phandle_prop)); 407}; 408 409/** 410 * overlay_fixup_phandle - Set an overlay phandle to the base one 411 * @fdt: Base Device Tree blob 412 * @fdto: Device tree overlay blob 413 * @symbols_off: Node offset of the symbols node in the base device tree 414 * @property: Property offset in the overlay holding the list of fixups 415 * 416 * overlay_fixup_phandle() resolves all the overlay phandles pointed 417 * to in a __fixups__ property, and updates them to match the phandles 418 * in use in the base device tree. 419 * 420 * This is part of the device tree overlay application process, when 421 * you want all the phandles in the overlay to point to the actual 422 * base dt nodes. 423 * 424 * returns: 425 * 0 on success 426 * Negative error code on failure 427 */ 428static int overlay_fixup_phandle(void *fdt, void *fdto, int symbols_off, 429 int property) 430{ 431 const char *value; 432 const char *label; 433 int len; 434 435 value = fdt_getprop_by_offset(fdto, property, 436 &label, &len); 437 if (!value) { 438 if (len == -FDT_ERR_NOTFOUND) 439 return -FDT_ERR_INTERNAL; 440 441 return len; 442 } 443 444 do { 445 const char *path, *name, *fixup_end; 446 const char *fixup_str = value; 447 uint32_t path_len, name_len; 448 uint32_t fixup_len; 449 char *sep, *endptr; 450 int poffset, ret; 451 452 fixup_end = memchr(value, '\0', len); 453 if (!fixup_end) 454 return -FDT_ERR_BADOVERLAY; 455 fixup_len = fixup_end - fixup_str; 456 457 len -= fixup_len + 1; 458 value += fixup_len + 1; 459 460 path = fixup_str; 461 sep = memchr(fixup_str, ':', fixup_len); 462 if (!sep || *sep != ':') 463 return -FDT_ERR_BADOVERLAY; 464 465 path_len = sep - path; 466 if (path_len == (fixup_len - 1)) 467 return -FDT_ERR_BADOVERLAY; 468 469 fixup_len -= path_len + 1; 470 name = sep + 1; 471 sep = memchr(name, ':', fixup_len); 472 if (!sep || *sep != ':') 473 return -FDT_ERR_BADOVERLAY; 474 475 name_len = sep - name; 476 if (!name_len) 477 return -FDT_ERR_BADOVERLAY; 478 479 poffset = strtoul(sep + 1, &endptr, 10); 480 if ((*endptr != '\0') || (endptr <= (sep + 1))) 481 return -FDT_ERR_BADOVERLAY; 482 483 ret = overlay_fixup_one_phandle(fdt, fdto, symbols_off, 484 path, path_len, name, name_len, 485 poffset, label); 486 if (ret) 487 return ret; 488 } while (len > 0); 489 490 return 0; 491} 492 493/** 494 * overlay_fixup_phandles - Resolve the overlay phandles to the base 495 * device tree 496 * @fdt: Base Device Tree blob 497 * @fdto: Device tree overlay blob 498 * 499 * overlay_fixup_phandles() resolves all the overlay phandles pointing 500 * to nodes in the base device tree. 501 * 502 * This is one of the steps of the device tree overlay application 503 * process, when you want all the phandles in the overlay to point to 504 * the actual base dt nodes. 505 * 506 * returns: 507 * 0 on success 508 * Negative error code on failure 509 */ 510static int overlay_fixup_phandles(void *fdt, void *fdto) 511{ 512 int fixups_off, symbols_off; 513 int property; 514 515 /* We can have overlays without any fixups */ 516 fixups_off = fdt_path_offset(fdto, "/__fixups__"); 517 if (fixups_off == -FDT_ERR_NOTFOUND) 518 return 0; /* nothing to do */ 519 if (fixups_off < 0) 520 return fixups_off; 521 522 /* And base DTs without symbols */ 523 symbols_off = fdt_path_offset(fdt, "/__symbols__"); 524 if ((symbols_off < 0 && (symbols_off != -FDT_ERR_NOTFOUND))) 525 return symbols_off; 526 527 fdt_for_each_property_offset(property, fdto, fixups_off) { 528 int ret; 529 530 ret = overlay_fixup_phandle(fdt, fdto, symbols_off, property); 531 if (ret) 532 return ret; 533 } 534 535 return 0; 536} 537 538/** 539 * overlay_apply_node - Merges a node into the base device tree 540 * @fdt: Base Device Tree blob 541 * @target: Node offset in the base device tree to apply the fragment to 542 * @fdto: Device tree overlay blob 543 * @node: Node offset in the overlay holding the changes to merge 544 * 545 * overlay_apply_node() merges a node into a target base device tree 546 * node pointed. 547 * 548 * This is part of the final step in the device tree overlay 549 * application process, when all the phandles have been adjusted and 550 * resolved and you just have to merge overlay into the base device 551 * tree. 552 * 553 * returns: 554 * 0 on success 555 * Negative error code on failure 556 */ 557static int overlay_apply_node(void *fdt, int target, 558 void *fdto, int node) 559{ 560 int property; 561 int subnode; 562 563 fdt_for_each_property_offset(property, fdto, node) { 564 const char *name; 565 const void *prop; 566 int prop_len; 567 int ret; 568 569 prop = fdt_getprop_by_offset(fdto, property, &name, 570 &prop_len); 571 if (prop_len == -FDT_ERR_NOTFOUND) 572 return -FDT_ERR_INTERNAL; 573 if (prop_len < 0) 574 return prop_len; 575 576 ret = fdt_setprop(fdt, target, name, prop, prop_len); 577 if (ret) 578 return ret; 579 } 580 581 fdt_for_each_subnode(subnode, fdto, node) { 582 const char *name = fdt_get_name(fdto, subnode, NULL); 583 int nnode; 584 int ret; 585 586 nnode = fdt_add_subnode(fdt, target, name); 587 if (nnode == -FDT_ERR_EXISTS) { 588 nnode = fdt_subnode_offset(fdt, target, name); 589 if (nnode == -FDT_ERR_NOTFOUND) 590 return -FDT_ERR_INTERNAL; 591 } 592 593 if (nnode < 0) 594 return nnode; 595 596 ret = overlay_apply_node(fdt, nnode, fdto, subnode); 597 if (ret) 598 return ret; 599 } 600 601 return 0; 602} 603 604/** 605 * overlay_merge - Merge an overlay into its base device tree 606 * @fdt: Base Device Tree blob 607 * @fdto: Device tree overlay blob 608 * 609 * overlay_merge() merges an overlay into its base device tree. 610 * 611 * This is the next to last step in the device tree overlay application 612 * process, when all the phandles have been adjusted and resolved and 613 * you just have to merge overlay into the base device tree. 614 * 615 * returns: 616 * 0 on success 617 * Negative error code on failure 618 */ 619static int overlay_merge(void *fdt, void *fdto) 620{ 621 int fragment; 622 623 fdt_for_each_subnode(fragment, fdto, 0) { 624 int overlay; 625 int target; 626 int ret; 627 628 /* 629 * Each fragments will have an __overlay__ node. If 630 * they don't, it's not supposed to be merged 631 */ 632 overlay = fdt_subnode_offset(fdto, fragment, "__overlay__"); 633 if (overlay == -FDT_ERR_NOTFOUND) 634 continue; 635 636 if (overlay < 0) 637 return overlay; 638 639 target = overlay_get_target(fdt, fdto, fragment, NULL); 640 if (target < 0) 641 return target; 642 643 ret = overlay_apply_node(fdt, target, fdto, overlay); 644 if (ret) 645 return ret; 646 } 647 648 return 0; 649} 650 651static int get_path_len(const void *fdt, int nodeoffset) 652{ 653 int len = 0, namelen; 654 const char *name; 655 656 FDT_RO_PROBE(fdt); 657 658 for (;;) { 659 name = fdt_get_name(fdt, nodeoffset, &namelen); 660 if (!name) 661 return namelen; 662 663 /* root? we're done */ 664 if (namelen == 0) 665 break; 666 667 nodeoffset = fdt_parent_offset(fdt, nodeoffset); 668 if (nodeoffset < 0) 669 return nodeoffset; 670 len += namelen + 1; 671 } 672 673 /* in case of root pretend it's "/" */ 674 if (len == 0) 675 len++; 676 return len; 677} 678 679/** 680 * overlay_symbol_update - Update the symbols of base tree after a merge 681 * @fdt: Base Device Tree blob 682 * @fdto: Device tree overlay blob 683 * 684 * overlay_symbol_update() updates the symbols of the base tree with the 685 * symbols of the applied overlay 686 * 687 * This is the last step in the device tree overlay application 688 * process, allowing the reference of overlay symbols by subsequent 689 * overlay operations. 690 * 691 * returns: 692 * 0 on success 693 * Negative error code on failure 694 */ 695static int overlay_symbol_update(void *fdt, void *fdto) 696{ 697 int root_sym, ov_sym, prop, path_len, fragment, target; 698 int len, frag_name_len, ret, rel_path_len; 699 const char *s, *e; 700 const char *path; 701 const char *name; 702 const char *frag_name; 703 const char *rel_path; 704 const char *target_path; 705 char *buf; 706 void *p; 707 708 ov_sym = fdt_subnode_offset(fdto, 0, "__symbols__"); 709 710 /* if no overlay symbols exist no problem */ 711 if (ov_sym < 0) 712 return 0; 713 714 root_sym = fdt_subnode_offset(fdt, 0, "__symbols__"); 715 716 /* it no root symbols exist we should create them */ 717 if (root_sym == -FDT_ERR_NOTFOUND) 718 root_sym = fdt_add_subnode(fdt, 0, "__symbols__"); 719 720 /* any error is fatal now */ 721 if (root_sym < 0) 722 return root_sym; 723 724 /* iterate over each overlay symbol */ 725 fdt_for_each_property_offset(prop, fdto, ov_sym) { 726 path = fdt_getprop_by_offset(fdto, prop, &name, &path_len); 727 if (!path) 728 return path_len; 729 730 /* verify it's a string property (terminated by a single \0) */ 731 if (path_len < 1 || memchr(path, '\0', path_len) != &path[path_len - 1]) 732 return -FDT_ERR_BADVALUE; 733 734 /* keep end marker to avoid strlen() */ 735 e = path + path_len; 736 737 if (*path != '/') 738 return -FDT_ERR_BADVALUE; 739 740 /* get fragment name first */ 741 s = strchr(path + 1, '/'); 742 if (!s) { 743 /* Symbol refers to something that won't end 744 * up in the target tree */ 745 continue; 746 } 747 748 frag_name = path + 1; 749 frag_name_len = s - path - 1; 750 751 /* verify format; safe since "s" lies in \0 terminated prop */ 752 len = sizeof("/__overlay__/") - 1; 753 if ((e - s) > len && (memcmp(s, "/__overlay__/", len) == 0)) { 754 /* /<fragment-name>/__overlay__/<relative-subnode-path> */ 755 rel_path = s + len; 756 rel_path_len = e - rel_path - 1; 757 } else if ((e - s) == len 758 && (memcmp(s, "/__overlay__", len - 1) == 0)) { 759 /* /<fragment-name>/__overlay__ */ 760 rel_path = ""; 761 rel_path_len = 0; 762 } else { 763 /* Symbol refers to something that won't end 764 * up in the target tree */ 765 continue; 766 } 767 768 /* find the fragment index in which the symbol lies */ 769 ret = fdt_subnode_offset_namelen(fdto, 0, frag_name, 770 frag_name_len); 771 /* not found? */ 772 if (ret < 0) 773 return -FDT_ERR_BADOVERLAY; 774 fragment = ret; 775 776 /* an __overlay__ subnode must exist */ 777 ret = fdt_subnode_offset(fdto, fragment, "__overlay__"); 778 if (ret < 0) 779 return -FDT_ERR_BADOVERLAY; 780 781 /* get the target of the fragment */ 782 ret = overlay_get_target(fdt, fdto, fragment, &target_path); 783 if (ret < 0) 784 return ret; 785 target = ret; 786 787 /* if we have a target path use */ 788 if (!target_path) { 789 ret = get_path_len(fdt, target); 790 if (ret < 0) 791 return ret; 792 len = ret; 793 } else { 794 len = strlen(target_path); 795 } 796 797 ret = fdt_setprop_placeholder(fdt, root_sym, name, 798 len + (len > 1) + rel_path_len + 1, &p); 799 if (ret < 0) 800 return ret; 801 802 if (!target_path) { 803 /* again in case setprop_placeholder changed it */ 804 ret = overlay_get_target(fdt, fdto, fragment, &target_path); 805 if (ret < 0) 806 return ret; 807 target = ret; 808 } 809 810 buf = p; 811 if (len > 1) { /* target is not root */ 812 if (!target_path) { 813 ret = fdt_get_path(fdt, target, buf, len + 1); 814 if (ret < 0) 815 return ret; 816 } else 817 memcpy(buf, target_path, len + 1); 818 819 } else 820 len--; 821 822 buf[len] = '/'; 823 memcpy(buf + len + 1, rel_path, rel_path_len); 824 buf[len + 1 + rel_path_len] = '\0'; 825 } 826 827 return 0; 828} 829 830int fdt_overlay_apply(void *fdt, void *fdto) 831{ 832 uint32_t delta; 833 int ret; 834 835 FDT_RO_PROBE(fdt); 836 FDT_RO_PROBE(fdto); 837 838 ret = fdt_find_max_phandle(fdt, &delta); 839 if (ret) 840 goto err; 841 842 ret = overlay_adjust_local_phandles(fdto, delta); 843 if (ret) 844 goto err; 845 846 ret = overlay_update_local_references(fdto, delta); 847 if (ret) 848 goto err; 849 850 ret = overlay_fixup_phandles(fdt, fdto); 851 if (ret) 852 goto err; 853 854 ret = overlay_merge(fdt, fdto); 855 if (ret) 856 goto err; 857 858 ret = overlay_symbol_update(fdt, fdto); 859 if (ret) 860 goto err; 861 862 /* 863 * The overlay has been damaged, erase its magic. 864 */ 865 fdt_set_magic(fdto, ~0); 866 867 return 0; 868 869err: 870 /* 871 * The overlay might have been damaged, erase its magic. 872 */ 873 fdt_set_magic(fdto, ~0); 874 875 /* 876 * The base device tree might have been damaged, erase its 877 * magic. 878 */ 879 fdt_set_magic(fdt, ~0); 880 881 return ret; 882} 883