1 /* $NetBSD: fdt_overlay.c,v 1.1.1.2 2019/12/22 12:30:38 skrll Exp $ */ 2 3 // SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause) 4 /* 5 * libfdt - Flat Device Tree manipulation 6 * Copyright (C) 2016 Free Electrons 7 * Copyright (C) 2016 NextThing Co. 8 */ 9 #include "libfdt_env.h" 10 11 #include <fdt.h> 12 #include <libfdt.h> 13 14 #include "libfdt_internal.h" 15 16 /** 17 * overlay_get_target_phandle - retrieves the target phandle of a fragment 18 * @fdto: pointer to the device tree overlay blob 19 * @fragment: node offset of the fragment in the overlay 20 * 21 * overlay_get_target_phandle() retrieves the target phandle of an 22 * overlay fragment when that fragment uses a phandle (target 23 * property) instead of a path (target-path property). 24 * 25 * returns: 26 * the phandle pointed by the target property 27 * 0, if the phandle was not found 28 * -1, if the phandle was malformed 29 */ 30 static uint32_t overlay_get_target_phandle(const void *fdto, int fragment) 31 { 32 const fdt32_t *val; 33 int len; 34 35 val = fdt_getprop(fdto, fragment, "target", &len); 36 if (!val) 37 return 0; 38 39 if ((len != sizeof(*val)) || (fdt32_to_cpu(*val) == (uint32_t)-1)) 40 return (uint32_t)-1; 41 42 return fdt32_to_cpu(*val); 43 } 44 45 /** 46 * overlay_get_target - retrieves the offset of a fragment's target 47 * @fdt: Base device tree blob 48 * @fdto: Device tree overlay blob 49 * @fragment: node offset of the fragment in the overlay 50 * @pathp: pointer which receives the path of the target (or NULL) 51 * 52 * overlay_get_target() retrieves the target offset in the base 53 * device tree of a fragment, no matter how the actual targeting is 54 * done (through a phandle or a path) 55 * 56 * returns: 57 * the targeted node offset in the base device tree 58 * Negative error code on error 59 */ 60 static int overlay_get_target(const void *fdt, const void *fdto, 61 int fragment, char const **pathp) 62 { 63 uint32_t phandle; 64 const char *path = NULL; 65 int path_len = 0, ret; 66 67 /* Try first to do a phandle based lookup */ 68 phandle = overlay_get_target_phandle(fdto, fragment); 69 if (phandle == (uint32_t)-1) 70 return -FDT_ERR_BADPHANDLE; 71 72 /* no phandle, try path */ 73 if (!phandle) { 74 /* And then a path based lookup */ 75 path = fdt_getprop(fdto, fragment, "target-path", &path_len); 76 if (path) 77 ret = fdt_path_offset(fdt, path); 78 else 79 ret = path_len; 80 } else 81 ret = fdt_node_offset_by_phandle(fdt, phandle); 82 83 /* 84 * If we haven't found either a target or a 85 * target-path property in a node that contains a 86 * __overlay__ subnode (we wouldn't be called 87 * otherwise), consider it a improperly written 88 * overlay 89 */ 90 if (ret < 0 && path_len == -FDT_ERR_NOTFOUND) 91 ret = -FDT_ERR_BADOVERLAY; 92 93 /* return on error */ 94 if (ret < 0) 95 return ret; 96 97 /* return pointer to path (if available) */ 98 if (pathp) 99 *pathp = path ? path : NULL; 100 101 return ret; 102 } 103 104 /** 105 * overlay_phandle_add_offset - Increases a phandle by an offset 106 * @fdt: Base device tree blob 107 * @node: Device tree overlay blob 108 * @name: Name of the property to modify (phandle or linux,phandle) 109 * @delta: offset to apply 110 * 111 * overlay_phandle_add_offset() increments a node phandle by a given 112 * offset. 113 * 114 * returns: 115 * 0 on success. 116 * Negative error code on error 117 */ 118 static int overlay_phandle_add_offset(void *fdt, int node, 119 const char *name, uint32_t delta) 120 { 121 const fdt32_t *val; 122 uint32_t adj_val; 123 int len; 124 125 val = fdt_getprop(fdt, node, name, &len); 126 if (!val) 127 return len; 128 129 if (len != sizeof(*val)) 130 return -FDT_ERR_BADPHANDLE; 131 132 adj_val = fdt32_to_cpu(*val); 133 if ((adj_val + delta) < adj_val) 134 return -FDT_ERR_NOPHANDLES; 135 136 adj_val += delta; 137 if (adj_val == (uint32_t)-1) 138 return -FDT_ERR_NOPHANDLES; 139 140 return fdt_setprop_inplace_u32(fdt, node, name, adj_val); 141 } 142 143 /** 144 * overlay_adjust_node_phandles - Offsets the phandles of a node 145 * @fdto: Device tree overlay blob 146 * @node: Offset of the node we want to adjust 147 * @delta: Offset to shift the phandles of 148 * 149 * overlay_adjust_node_phandles() adds a constant to all the phandles 150 * of a given node. This is mainly use as part of the overlay 151 * application process, when we want to update all the overlay 152 * phandles to not conflict with the overlays of the base device tree. 153 * 154 * returns: 155 * 0 on success 156 * Negative error code on failure 157 */ 158 static int overlay_adjust_node_phandles(void *fdto, int node, 159 uint32_t delta) 160 { 161 int child; 162 int ret; 163 164 ret = overlay_phandle_add_offset(fdto, node, "phandle", delta); 165 if (ret && ret != -FDT_ERR_NOTFOUND) 166 return ret; 167 168 ret = overlay_phandle_add_offset(fdto, node, "linux,phandle", delta); 169 if (ret && ret != -FDT_ERR_NOTFOUND) 170 return ret; 171 172 fdt_for_each_subnode(child, fdto, node) { 173 ret = overlay_adjust_node_phandles(fdto, child, delta); 174 if (ret) 175 return ret; 176 } 177 178 return 0; 179 } 180 181 /** 182 * overlay_adjust_local_phandles - Adjust the phandles of a whole overlay 183 * @fdto: Device tree overlay blob 184 * @delta: Offset to shift the phandles of 185 * 186 * overlay_adjust_local_phandles() adds a constant to all the 187 * phandles of an overlay. This is mainly use as part of the overlay 188 * application process, when we want to update all the overlay 189 * phandles to not conflict with the overlays of the base device tree. 190 * 191 * returns: 192 * 0 on success 193 * Negative error code on failure 194 */ 195 static int overlay_adjust_local_phandles(void *fdto, uint32_t delta) 196 { 197 /* 198 * Start adjusting the phandles from the overlay root 199 */ 200 return overlay_adjust_node_phandles(fdto, 0, delta); 201 } 202 203 /** 204 * overlay_update_local_node_references - Adjust the overlay references 205 * @fdto: Device tree overlay blob 206 * @tree_node: Node offset of the node to operate on 207 * @fixup_node: Node offset of the matching local fixups node 208 * @delta: Offset to shift the phandles of 209 * 210 * overlay_update_local_nodes_references() update the phandles 211 * pointing to a node within the device tree overlay by adding a 212 * constant delta. 213 * 214 * This is mainly used as part of a device tree application process, 215 * where you want the device tree overlays phandles to not conflict 216 * with the ones from the base device tree before merging them. 217 * 218 * returns: 219 * 0 on success 220 * Negative error code on failure 221 */ 222 static int overlay_update_local_node_references(void *fdto, 223 int tree_node, 224 int fixup_node, 225 uint32_t delta) 226 { 227 int fixup_prop; 228 int fixup_child; 229 int ret; 230 231 fdt_for_each_property_offset(fixup_prop, fdto, fixup_node) { 232 const fdt32_t *fixup_val; 233 const char *tree_val; 234 const char *name; 235 int fixup_len; 236 int tree_len; 237 int i; 238 239 fixup_val = fdt_getprop_by_offset(fdto, fixup_prop, 240 &name, &fixup_len); 241 if (!fixup_val) 242 return fixup_len; 243 244 if (fixup_len % sizeof(uint32_t)) 245 return -FDT_ERR_BADOVERLAY; 246 247 tree_val = fdt_getprop(fdto, tree_node, name, &tree_len); 248 if (!tree_val) { 249 if (tree_len == -FDT_ERR_NOTFOUND) 250 return -FDT_ERR_BADOVERLAY; 251 252 return tree_len; 253 } 254 255 for (i = 0; i < (fixup_len / sizeof(uint32_t)); i++) { 256 fdt32_t adj_val; 257 uint32_t poffset; 258 259 poffset = fdt32_to_cpu(fixup_val[i]); 260 261 /* 262 * phandles to fixup can be unaligned. 263 * 264 * Use a memcpy for the architectures that do 265 * not support unaligned accesses. 266 */ 267 memcpy(&adj_val, tree_val + poffset, sizeof(adj_val)); 268 269 adj_val = cpu_to_fdt32(fdt32_to_cpu(adj_val) + delta); 270 271 ret = fdt_setprop_inplace_namelen_partial(fdto, 272 tree_node, 273 name, 274 strlen(name), 275 poffset, 276 &adj_val, 277 sizeof(adj_val)); 278 if (ret == -FDT_ERR_NOSPACE) 279 return -FDT_ERR_BADOVERLAY; 280 281 if (ret) 282 return ret; 283 } 284 } 285 286 fdt_for_each_subnode(fixup_child, fdto, fixup_node) { 287 const char *fixup_child_name = fdt_get_name(fdto, fixup_child, 288 NULL); 289 int tree_child; 290 291 tree_child = fdt_subnode_offset(fdto, tree_node, 292 fixup_child_name); 293 if (tree_child == -FDT_ERR_NOTFOUND) 294 return -FDT_ERR_BADOVERLAY; 295 if (tree_child < 0) 296 return tree_child; 297 298 ret = overlay_update_local_node_references(fdto, 299 tree_child, 300 fixup_child, 301 delta); 302 if (ret) 303 return ret; 304 } 305 306 return 0; 307 } 308 309 /** 310 * overlay_update_local_references - Adjust the overlay references 311 * @fdto: Device tree overlay blob 312 * @delta: Offset to shift the phandles of 313 * 314 * overlay_update_local_references() update all the phandles pointing 315 * to a node within the device tree overlay by adding a constant 316 * delta to not conflict with the base overlay. 317 * 318 * This is mainly used as part of a device tree application process, 319 * where you want the device tree overlays phandles to not conflict 320 * with the ones from the base device tree before merging them. 321 * 322 * returns: 323 * 0 on success 324 * Negative error code on failure 325 */ 326 static int overlay_update_local_references(void *fdto, uint32_t delta) 327 { 328 int fixups; 329 330 fixups = fdt_path_offset(fdto, "/__local_fixups__"); 331 if (fixups < 0) { 332 /* There's no local phandles to adjust, bail out */ 333 if (fixups == -FDT_ERR_NOTFOUND) 334 return 0; 335 336 return fixups; 337 } 338 339 /* 340 * Update our local references from the root of the tree 341 */ 342 return overlay_update_local_node_references(fdto, 0, fixups, 343 delta); 344 } 345 346 /** 347 * overlay_fixup_one_phandle - Set an overlay phandle to the base one 348 * @fdt: Base Device Tree blob 349 * @fdto: Device tree overlay blob 350 * @symbols_off: Node offset of the symbols node in the base device tree 351 * @path: Path to a node holding a phandle in the overlay 352 * @path_len: number of path characters to consider 353 * @name: Name of the property holding the phandle reference in the overlay 354 * @name_len: number of name characters to consider 355 * @poffset: Offset within the overlay property where the phandle is stored 356 * @label: Label of the node referenced by the phandle 357 * 358 * overlay_fixup_one_phandle() resolves an overlay phandle pointing to 359 * a node in the base device tree. 360 * 361 * This is part of the device tree overlay application process, when 362 * you want all the phandles in the overlay to point to the actual 363 * base dt nodes. 364 * 365 * returns: 366 * 0 on success 367 * Negative error code on failure 368 */ 369 static int overlay_fixup_one_phandle(void *fdt, void *fdto, 370 int symbols_off, 371 const char *path, uint32_t path_len, 372 const char *name, uint32_t name_len, 373 int poffset, const char *label) 374 { 375 const char *symbol_path; 376 uint32_t phandle; 377 fdt32_t phandle_prop; 378 int symbol_off, fixup_off; 379 int prop_len; 380 381 if (symbols_off < 0) 382 return symbols_off; 383 384 symbol_path = fdt_getprop(fdt, symbols_off, label, 385 &prop_len); 386 if (!symbol_path) 387 return prop_len; 388 389 symbol_off = fdt_path_offset(fdt, symbol_path); 390 if (symbol_off < 0) 391 return symbol_off; 392 393 phandle = fdt_get_phandle(fdt, symbol_off); 394 if (!phandle) 395 return -FDT_ERR_NOTFOUND; 396 397 fixup_off = fdt_path_offset_namelen(fdto, path, path_len); 398 if (fixup_off == -FDT_ERR_NOTFOUND) 399 return -FDT_ERR_BADOVERLAY; 400 if (fixup_off < 0) 401 return fixup_off; 402 403 phandle_prop = cpu_to_fdt32(phandle); 404 return fdt_setprop_inplace_namelen_partial(fdto, fixup_off, 405 name, name_len, poffset, 406 &phandle_prop, 407 sizeof(phandle_prop)); 408 }; 409 410 /** 411 * overlay_fixup_phandle - Set an overlay phandle to the base one 412 * @fdt: Base Device Tree blob 413 * @fdto: Device tree overlay blob 414 * @symbols_off: Node offset of the symbols node in the base device tree 415 * @property: Property offset in the overlay holding the list of fixups 416 * 417 * overlay_fixup_phandle() resolves all the overlay phandles pointed 418 * to in a __fixups__ property, and updates them to match the phandles 419 * in use in the base device tree. 420 * 421 * This is part of the device tree overlay application process, when 422 * you want all the phandles in the overlay to point to the actual 423 * base dt nodes. 424 * 425 * returns: 426 * 0 on success 427 * Negative error code on failure 428 */ 429 static int overlay_fixup_phandle(void *fdt, void *fdto, int symbols_off, 430 int property) 431 { 432 const char *value; 433 const char *label; 434 int len; 435 436 value = fdt_getprop_by_offset(fdto, property, 437 &label, &len); 438 if (!value) { 439 if (len == -FDT_ERR_NOTFOUND) 440 return -FDT_ERR_INTERNAL; 441 442 return len; 443 } 444 445 do { 446 const char *path, *name, *fixup_end; 447 const char *fixup_str = value; 448 uint32_t path_len, name_len; 449 uint32_t fixup_len; 450 char *sep, *endptr; 451 int poffset, ret; 452 453 fixup_end = memchr(value, '\0', len); 454 if (!fixup_end) 455 return -FDT_ERR_BADOVERLAY; 456 fixup_len = fixup_end - fixup_str; 457 458 len -= fixup_len + 1; 459 value += fixup_len + 1; 460 461 path = fixup_str; 462 sep = memchr(fixup_str, ':', fixup_len); 463 if (!sep || *sep != ':') 464 return -FDT_ERR_BADOVERLAY; 465 466 path_len = sep - path; 467 if (path_len == (fixup_len - 1)) 468 return -FDT_ERR_BADOVERLAY; 469 470 fixup_len -= path_len + 1; 471 name = sep + 1; 472 sep = memchr(name, ':', fixup_len); 473 if (!sep || *sep != ':') 474 return -FDT_ERR_BADOVERLAY; 475 476 name_len = sep - name; 477 if (!name_len) 478 return -FDT_ERR_BADOVERLAY; 479 480 poffset = strtoul(sep + 1, &endptr, 10); 481 if ((*endptr != '\0') || (endptr <= (sep + 1))) 482 return -FDT_ERR_BADOVERLAY; 483 484 ret = overlay_fixup_one_phandle(fdt, fdto, symbols_off, 485 path, path_len, name, name_len, 486 poffset, label); 487 if (ret) 488 return ret; 489 } while (len > 0); 490 491 return 0; 492 } 493 494 /** 495 * overlay_fixup_phandles - Resolve the overlay phandles to the base 496 * device tree 497 * @fdt: Base Device Tree blob 498 * @fdto: Device tree overlay blob 499 * 500 * overlay_fixup_phandles() resolves all the overlay phandles pointing 501 * to nodes in the base device tree. 502 * 503 * This is one of the steps of the device tree overlay application 504 * process, when you want all the phandles in the overlay to point to 505 * the actual base dt nodes. 506 * 507 * returns: 508 * 0 on success 509 * Negative error code on failure 510 */ 511 static int overlay_fixup_phandles(void *fdt, void *fdto) 512 { 513 int fixups_off, symbols_off; 514 int property; 515 516 /* We can have overlays without any fixups */ 517 fixups_off = fdt_path_offset(fdto, "/__fixups__"); 518 if (fixups_off == -FDT_ERR_NOTFOUND) 519 return 0; /* nothing to do */ 520 if (fixups_off < 0) 521 return fixups_off; 522 523 /* And base DTs without symbols */ 524 symbols_off = fdt_path_offset(fdt, "/__symbols__"); 525 if ((symbols_off < 0 && (symbols_off != -FDT_ERR_NOTFOUND))) 526 return symbols_off; 527 528 fdt_for_each_property_offset(property, fdto, fixups_off) { 529 int ret; 530 531 ret = overlay_fixup_phandle(fdt, fdto, symbols_off, property); 532 if (ret) 533 return ret; 534 } 535 536 return 0; 537 } 538 539 /** 540 * overlay_apply_node - Merges a node into the base device tree 541 * @fdt: Base Device Tree blob 542 * @target: Node offset in the base device tree to apply the fragment to 543 * @fdto: Device tree overlay blob 544 * @node: Node offset in the overlay holding the changes to merge 545 * 546 * overlay_apply_node() merges a node into a target base device tree 547 * node pointed. 548 * 549 * This is part of the final step in the device tree overlay 550 * application process, when all the phandles have been adjusted and 551 * resolved and you just have to merge overlay into the base device 552 * tree. 553 * 554 * returns: 555 * 0 on success 556 * Negative error code on failure 557 */ 558 static int overlay_apply_node(void *fdt, int target, 559 void *fdto, int node) 560 { 561 int property; 562 int subnode; 563 564 fdt_for_each_property_offset(property, fdto, node) { 565 const char *name; 566 const void *prop; 567 int prop_len; 568 int ret; 569 570 prop = fdt_getprop_by_offset(fdto, property, &name, 571 &prop_len); 572 if (prop_len == -FDT_ERR_NOTFOUND) 573 return -FDT_ERR_INTERNAL; 574 if (prop_len < 0) 575 return prop_len; 576 577 ret = fdt_setprop(fdt, target, name, prop, prop_len); 578 if (ret) 579 return ret; 580 } 581 582 fdt_for_each_subnode(subnode, fdto, node) { 583 const char *name = fdt_get_name(fdto, subnode, NULL); 584 int nnode; 585 int ret; 586 587 nnode = fdt_add_subnode(fdt, target, name); 588 if (nnode == -FDT_ERR_EXISTS) { 589 nnode = fdt_subnode_offset(fdt, target, name); 590 if (nnode == -FDT_ERR_NOTFOUND) 591 return -FDT_ERR_INTERNAL; 592 } 593 594 if (nnode < 0) 595 return nnode; 596 597 ret = overlay_apply_node(fdt, nnode, fdto, subnode); 598 if (ret) 599 return ret; 600 } 601 602 return 0; 603 } 604 605 /** 606 * overlay_merge - Merge an overlay into its base device tree 607 * @fdt: Base Device Tree blob 608 * @fdto: Device tree overlay blob 609 * 610 * overlay_merge() merges an overlay into its base device tree. 611 * 612 * This is the next to last step in the device tree overlay application 613 * process, when all the phandles have been adjusted and resolved and 614 * you just have to merge overlay into the base device tree. 615 * 616 * returns: 617 * 0 on success 618 * Negative error code on failure 619 */ 620 static int overlay_merge(void *fdt, void *fdto) 621 { 622 int fragment; 623 624 fdt_for_each_subnode(fragment, fdto, 0) { 625 int overlay; 626 int target; 627 int ret; 628 629 /* 630 * Each fragments will have an __overlay__ node. If 631 * they don't, it's not supposed to be merged 632 */ 633 overlay = fdt_subnode_offset(fdto, fragment, "__overlay__"); 634 if (overlay == -FDT_ERR_NOTFOUND) 635 continue; 636 637 if (overlay < 0) 638 return overlay; 639 640 target = overlay_get_target(fdt, fdto, fragment, NULL); 641 if (target < 0) 642 return target; 643 644 ret = overlay_apply_node(fdt, target, fdto, overlay); 645 if (ret) 646 return ret; 647 } 648 649 return 0; 650 } 651 652 static int get_path_len(const void *fdt, int nodeoffset) 653 { 654 int len = 0, namelen; 655 const char *name; 656 657 FDT_RO_PROBE(fdt); 658 659 for (;;) { 660 name = fdt_get_name(fdt, nodeoffset, &namelen); 661 if (!name) 662 return namelen; 663 664 /* root? we're done */ 665 if (namelen == 0) 666 break; 667 668 nodeoffset = fdt_parent_offset(fdt, nodeoffset); 669 if (nodeoffset < 0) 670 return nodeoffset; 671 len += namelen + 1; 672 } 673 674 /* in case of root pretend it's "/" */ 675 if (len == 0) 676 len++; 677 return len; 678 } 679 680 /** 681 * overlay_symbol_update - Update the symbols of base tree after a merge 682 * @fdt: Base Device Tree blob 683 * @fdto: Device tree overlay blob 684 * 685 * overlay_symbol_update() updates the symbols of the base tree with the 686 * symbols of the applied overlay 687 * 688 * This is the last step in the device tree overlay application 689 * process, allowing the reference of overlay symbols by subsequent 690 * overlay operations. 691 * 692 * returns: 693 * 0 on success 694 * Negative error code on failure 695 */ 696 static int overlay_symbol_update(void *fdt, void *fdto) 697 { 698 int root_sym, ov_sym, prop, path_len, fragment, target; 699 int len, frag_name_len, ret, rel_path_len; 700 const char *s, *e; 701 const char *path; 702 const char *name; 703 const char *frag_name; 704 const char *rel_path; 705 const char *target_path; 706 char *buf; 707 void *p; 708 709 ov_sym = fdt_subnode_offset(fdto, 0, "__symbols__"); 710 711 /* if no overlay symbols exist no problem */ 712 if (ov_sym < 0) 713 return 0; 714 715 root_sym = fdt_subnode_offset(fdt, 0, "__symbols__"); 716 717 /* it no root symbols exist we should create them */ 718 if (root_sym == -FDT_ERR_NOTFOUND) 719 root_sym = fdt_add_subnode(fdt, 0, "__symbols__"); 720 721 /* any error is fatal now */ 722 if (root_sym < 0) 723 return root_sym; 724 725 /* iterate over each overlay symbol */ 726 fdt_for_each_property_offset(prop, fdto, ov_sym) { 727 path = fdt_getprop_by_offset(fdto, prop, &name, &path_len); 728 if (!path) 729 return path_len; 730 731 /* verify it's a string property (terminated by a single \0) */ 732 if (path_len < 1 || memchr(path, '\0', path_len) != &path[path_len - 1]) 733 return -FDT_ERR_BADVALUE; 734 735 /* keep end marker to avoid strlen() */ 736 e = path + path_len; 737 738 if (*path != '/') 739 return -FDT_ERR_BADVALUE; 740 741 /* get fragment name first */ 742 s = strchr(path + 1, '/'); 743 if (!s) { 744 /* Symbol refers to something that won't end 745 * up in the target tree */ 746 continue; 747 } 748 749 frag_name = path + 1; 750 frag_name_len = s - path - 1; 751 752 /* verify format; safe since "s" lies in \0 terminated prop */ 753 len = sizeof("/__overlay__/") - 1; 754 if ((e - s) > len && (memcmp(s, "/__overlay__/", len) == 0)) { 755 /* /<fragment-name>/__overlay__/<relative-subnode-path> */ 756 rel_path = s + len; 757 rel_path_len = e - rel_path; 758 } else if ((e - s) == len 759 && (memcmp(s, "/__overlay__", len - 1) == 0)) { 760 /* /<fragment-name>/__overlay__ */ 761 rel_path = ""; 762 rel_path_len = 0; 763 } else { 764 /* Symbol refers to something that won't end 765 * up in the target tree */ 766 continue; 767 } 768 769 /* find the fragment index in which the symbol lies */ 770 ret = fdt_subnode_offset_namelen(fdto, 0, frag_name, 771 frag_name_len); 772 /* not found? */ 773 if (ret < 0) 774 return -FDT_ERR_BADOVERLAY; 775 fragment = ret; 776 777 /* an __overlay__ subnode must exist */ 778 ret = fdt_subnode_offset(fdto, fragment, "__overlay__"); 779 if (ret < 0) 780 return -FDT_ERR_BADOVERLAY; 781 782 /* get the target of the fragment */ 783 ret = overlay_get_target(fdt, fdto, fragment, &target_path); 784 if (ret < 0) 785 return ret; 786 target = ret; 787 788 /* if we have a target path use */ 789 if (!target_path) { 790 ret = get_path_len(fdt, target); 791 if (ret < 0) 792 return ret; 793 len = ret; 794 } else { 795 len = strlen(target_path); 796 } 797 798 ret = fdt_setprop_placeholder(fdt, root_sym, name, 799 len + (len > 1) + rel_path_len + 1, &p); 800 if (ret < 0) 801 return ret; 802 803 if (!target_path) { 804 /* again in case setprop_placeholder changed it */ 805 ret = overlay_get_target(fdt, fdto, fragment, &target_path); 806 if (ret < 0) 807 return ret; 808 target = ret; 809 } 810 811 buf = p; 812 if (len > 1) { /* target is not root */ 813 if (!target_path) { 814 ret = fdt_get_path(fdt, target, buf, len + 1); 815 if (ret < 0) 816 return ret; 817 } else 818 memcpy(buf, target_path, len + 1); 819 820 } else 821 len--; 822 823 buf[len] = '/'; 824 memcpy(buf + len + 1, rel_path, rel_path_len); 825 buf[len + 1 + rel_path_len] = '\0'; 826 } 827 828 return 0; 829 } 830 831 int fdt_overlay_apply(void *fdt, void *fdto) 832 { 833 uint32_t delta; 834 int ret; 835 836 FDT_RO_PROBE(fdt); 837 FDT_RO_PROBE(fdto); 838 839 ret = fdt_find_max_phandle(fdt, &delta); 840 if (ret) 841 goto err; 842 843 ret = overlay_adjust_local_phandles(fdto, delta); 844 if (ret) 845 goto err; 846 847 ret = overlay_update_local_references(fdto, delta); 848 if (ret) 849 goto err; 850 851 ret = overlay_fixup_phandles(fdt, fdto); 852 if (ret) 853 goto err; 854 855 ret = overlay_merge(fdt, fdto); 856 if (ret) 857 goto err; 858 859 ret = overlay_symbol_update(fdt, fdto); 860 if (ret) 861 goto err; 862 863 /* 864 * The overlay has been damaged, erase its magic. 865 */ 866 fdt_set_magic(fdto, ~0); 867 868 return 0; 869 870 err: 871 /* 872 * The overlay might have been damaged, erase its magic. 873 */ 874 fdt_set_magic(fdto, ~0); 875 876 /* 877 * The base device tree might have been damaged, erase its 878 * magic. 879 */ 880 fdt_set_magic(fdt, ~0); 881 882 return ret; 883 } 884