1 /* 2 * Procedures for creating, accessing and interpreting the device tree. 3 * 4 * Paul Mackerras August 1996. 5 * Copyright (C) 1996-2005 Paul Mackerras. 6 * 7 * Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner. 8 * {engebret|bergner}@us.ibm.com 9 * 10 * Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net 11 * 12 * Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and 13 * Grant Likely. 14 * 15 * This program is free software; you can redistribute it and/or 16 * modify it under the terms of the GNU General Public License 17 * as published by the Free Software Foundation; either version 18 * 2 of the License, or (at your option) any later version. 19 */ 20 #include <linux/module.h> 21 #include <linux/of.h> 22 #include <linux/spinlock.h> 23 #include <linux/slab.h> 24 #include <linux/proc_fs.h> 25 26 struct device_node *allnodes; 27 struct device_node *of_chosen; 28 29 /* use when traversing tree through the allnext, child, sibling, 30 * or parent members of struct device_node. 31 */ 32 DEFINE_RWLOCK(devtree_lock); 33 34 int of_n_addr_cells(struct device_node *np) 35 { 36 const __be32 *ip; 37 38 do { 39 if (np->parent) 40 np = np->parent; 41 ip = of_get_property(np, "#address-cells", NULL); 42 if (ip) 43 return be32_to_cpup(ip); 44 } while (np->parent); 45 /* No #address-cells property for the root node */ 46 return OF_ROOT_NODE_ADDR_CELLS_DEFAULT; 47 } 48 EXPORT_SYMBOL(of_n_addr_cells); 49 50 int of_n_size_cells(struct device_node *np) 51 { 52 const __be32 *ip; 53 54 do { 55 if (np->parent) 56 np = np->parent; 57 ip = of_get_property(np, "#size-cells", NULL); 58 if (ip) 59 return be32_to_cpup(ip); 60 } while (np->parent); 61 /* No #size-cells property for the root node */ 62 return OF_ROOT_NODE_SIZE_CELLS_DEFAULT; 63 } 64 EXPORT_SYMBOL(of_n_size_cells); 65 66 #if !defined(CONFIG_SPARC) /* SPARC doesn't do ref counting (yet) */ 67 /** 68 * of_node_get - Increment refcount of a node 69 * @node: Node to inc refcount, NULL is supported to 70 * simplify writing of callers 71 * 72 * Returns node. 73 */ 74 struct device_node *of_node_get(struct device_node *node) 75 { 76 if (node) 77 kref_get(&node->kref); 78 return node; 79 } 80 EXPORT_SYMBOL(of_node_get); 81 82 static inline struct device_node *kref_to_device_node(struct kref *kref) 83 { 84 return container_of(kref, struct device_node, kref); 85 } 86 87 /** 88 * of_node_release - release a dynamically allocated node 89 * @kref: kref element of the node to be released 90 * 91 * In of_node_put() this function is passed to kref_put() 92 * as the destructor. 93 */ 94 static void of_node_release(struct kref *kref) 95 { 96 struct device_node *node = kref_to_device_node(kref); 97 struct property *prop = node->properties; 98 99 /* We should never be releasing nodes that haven't been detached. */ 100 if (!of_node_check_flag(node, OF_DETACHED)) { 101 pr_err("ERROR: Bad of_node_put() on %s\n", node->full_name); 102 dump_stack(); 103 kref_init(&node->kref); 104 return; 105 } 106 107 if (!of_node_check_flag(node, OF_DYNAMIC)) 108 return; 109 110 while (prop) { 111 struct property *next = prop->next; 112 kfree(prop->name); 113 kfree(prop->value); 114 kfree(prop); 115 prop = next; 116 117 if (!prop) { 118 prop = node->deadprops; 119 node->deadprops = NULL; 120 } 121 } 122 kfree(node->full_name); 123 kfree(node->data); 124 kfree(node); 125 } 126 127 /** 128 * of_node_put - Decrement refcount of a node 129 * @node: Node to dec refcount, NULL is supported to 130 * simplify writing of callers 131 * 132 */ 133 void of_node_put(struct device_node *node) 134 { 135 if (node) 136 kref_put(&node->kref, of_node_release); 137 } 138 EXPORT_SYMBOL(of_node_put); 139 #endif /* !CONFIG_SPARC */ 140 141 struct property *of_find_property(const struct device_node *np, 142 const char *name, 143 int *lenp) 144 { 145 struct property *pp; 146 147 if (!np) 148 return NULL; 149 150 read_lock(&devtree_lock); 151 for (pp = np->properties; pp != 0; pp = pp->next) { 152 if (of_prop_cmp(pp->name, name) == 0) { 153 if (lenp != 0) 154 *lenp = pp->length; 155 break; 156 } 157 } 158 read_unlock(&devtree_lock); 159 160 return pp; 161 } 162 EXPORT_SYMBOL(of_find_property); 163 164 /** 165 * of_find_all_nodes - Get next node in global list 166 * @prev: Previous node or NULL to start iteration 167 * of_node_put() will be called on it 168 * 169 * Returns a node pointer with refcount incremented, use 170 * of_node_put() on it when done. 171 */ 172 struct device_node *of_find_all_nodes(struct device_node *prev) 173 { 174 struct device_node *np; 175 176 read_lock(&devtree_lock); 177 np = prev ? prev->allnext : allnodes; 178 for (; np != NULL; np = np->allnext) 179 if (of_node_get(np)) 180 break; 181 of_node_put(prev); 182 read_unlock(&devtree_lock); 183 return np; 184 } 185 EXPORT_SYMBOL(of_find_all_nodes); 186 187 /* 188 * Find a property with a given name for a given node 189 * and return the value. 190 */ 191 const void *of_get_property(const struct device_node *np, const char *name, 192 int *lenp) 193 { 194 struct property *pp = of_find_property(np, name, lenp); 195 196 return pp ? pp->value : NULL; 197 } 198 EXPORT_SYMBOL(of_get_property); 199 200 /** Checks if the given "compat" string matches one of the strings in 201 * the device's "compatible" property 202 */ 203 int of_device_is_compatible(const struct device_node *device, 204 const char *compat) 205 { 206 const char* cp; 207 int cplen, l; 208 209 cp = of_get_property(device, "compatible", &cplen); 210 if (cp == NULL) 211 return 0; 212 while (cplen > 0) { 213 if (of_compat_cmp(cp, compat, strlen(compat)) == 0) 214 return 1; 215 l = strlen(cp) + 1; 216 cp += l; 217 cplen -= l; 218 } 219 220 return 0; 221 } 222 EXPORT_SYMBOL(of_device_is_compatible); 223 224 /** 225 * of_machine_is_compatible - Test root of device tree for a given compatible value 226 * @compat: compatible string to look for in root node's compatible property. 227 * 228 * Returns true if the root node has the given value in its 229 * compatible property. 230 */ 231 int of_machine_is_compatible(const char *compat) 232 { 233 struct device_node *root; 234 int rc = 0; 235 236 root = of_find_node_by_path("/"); 237 if (root) { 238 rc = of_device_is_compatible(root, compat); 239 of_node_put(root); 240 } 241 return rc; 242 } 243 EXPORT_SYMBOL(of_machine_is_compatible); 244 245 /** 246 * of_device_is_available - check if a device is available for use 247 * 248 * @device: Node to check for availability 249 * 250 * Returns 1 if the status property is absent or set to "okay" or "ok", 251 * 0 otherwise 252 */ 253 int of_device_is_available(const struct device_node *device) 254 { 255 const char *status; 256 int statlen; 257 258 status = of_get_property(device, "status", &statlen); 259 if (status == NULL) 260 return 1; 261 262 if (statlen > 0) { 263 if (!strcmp(status, "okay") || !strcmp(status, "ok")) 264 return 1; 265 } 266 267 return 0; 268 } 269 EXPORT_SYMBOL(of_device_is_available); 270 271 /** 272 * of_get_parent - Get a node's parent if any 273 * @node: Node to get parent 274 * 275 * Returns a node pointer with refcount incremented, use 276 * of_node_put() on it when done. 277 */ 278 struct device_node *of_get_parent(const struct device_node *node) 279 { 280 struct device_node *np; 281 282 if (!node) 283 return NULL; 284 285 read_lock(&devtree_lock); 286 np = of_node_get(node->parent); 287 read_unlock(&devtree_lock); 288 return np; 289 } 290 EXPORT_SYMBOL(of_get_parent); 291 292 /** 293 * of_get_next_parent - Iterate to a node's parent 294 * @node: Node to get parent of 295 * 296 * This is like of_get_parent() except that it drops the 297 * refcount on the passed node, making it suitable for iterating 298 * through a node's parents. 299 * 300 * Returns a node pointer with refcount incremented, use 301 * of_node_put() on it when done. 302 */ 303 struct device_node *of_get_next_parent(struct device_node *node) 304 { 305 struct device_node *parent; 306 307 if (!node) 308 return NULL; 309 310 read_lock(&devtree_lock); 311 parent = of_node_get(node->parent); 312 of_node_put(node); 313 read_unlock(&devtree_lock); 314 return parent; 315 } 316 317 /** 318 * of_get_next_child - Iterate a node childs 319 * @node: parent node 320 * @prev: previous child of the parent node, or NULL to get first 321 * 322 * Returns a node pointer with refcount incremented, use 323 * of_node_put() on it when done. 324 */ 325 struct device_node *of_get_next_child(const struct device_node *node, 326 struct device_node *prev) 327 { 328 struct device_node *next; 329 330 read_lock(&devtree_lock); 331 next = prev ? prev->sibling : node->child; 332 for (; next; next = next->sibling) 333 if (of_node_get(next)) 334 break; 335 of_node_put(prev); 336 read_unlock(&devtree_lock); 337 return next; 338 } 339 EXPORT_SYMBOL(of_get_next_child); 340 341 /** 342 * of_find_node_by_path - Find a node matching a full OF path 343 * @path: The full path to match 344 * 345 * Returns a node pointer with refcount incremented, use 346 * of_node_put() on it when done. 347 */ 348 struct device_node *of_find_node_by_path(const char *path) 349 { 350 struct device_node *np = allnodes; 351 352 read_lock(&devtree_lock); 353 for (; np; np = np->allnext) { 354 if (np->full_name && (of_node_cmp(np->full_name, path) == 0) 355 && of_node_get(np)) 356 break; 357 } 358 read_unlock(&devtree_lock); 359 return np; 360 } 361 EXPORT_SYMBOL(of_find_node_by_path); 362 363 /** 364 * of_find_node_by_name - Find a node by its "name" property 365 * @from: The node to start searching from or NULL, the node 366 * you pass will not be searched, only the next one 367 * will; typically, you pass what the previous call 368 * returned. of_node_put() will be called on it 369 * @name: The name string to match against 370 * 371 * Returns a node pointer with refcount incremented, use 372 * of_node_put() on it when done. 373 */ 374 struct device_node *of_find_node_by_name(struct device_node *from, 375 const char *name) 376 { 377 struct device_node *np; 378 379 read_lock(&devtree_lock); 380 np = from ? from->allnext : allnodes; 381 for (; np; np = np->allnext) 382 if (np->name && (of_node_cmp(np->name, name) == 0) 383 && of_node_get(np)) 384 break; 385 of_node_put(from); 386 read_unlock(&devtree_lock); 387 return np; 388 } 389 EXPORT_SYMBOL(of_find_node_by_name); 390 391 /** 392 * of_find_node_by_type - Find a node by its "device_type" property 393 * @from: The node to start searching from, or NULL to start searching 394 * the entire device tree. The node you pass will not be 395 * searched, only the next one will; typically, you pass 396 * what the previous call returned. of_node_put() will be 397 * called on from for you. 398 * @type: The type string to match against 399 * 400 * Returns a node pointer with refcount incremented, use 401 * of_node_put() on it when done. 402 */ 403 struct device_node *of_find_node_by_type(struct device_node *from, 404 const char *type) 405 { 406 struct device_node *np; 407 408 read_lock(&devtree_lock); 409 np = from ? from->allnext : allnodes; 410 for (; np; np = np->allnext) 411 if (np->type && (of_node_cmp(np->type, type) == 0) 412 && of_node_get(np)) 413 break; 414 of_node_put(from); 415 read_unlock(&devtree_lock); 416 return np; 417 } 418 EXPORT_SYMBOL(of_find_node_by_type); 419 420 /** 421 * of_find_compatible_node - Find a node based on type and one of the 422 * tokens in its "compatible" property 423 * @from: The node to start searching from or NULL, the node 424 * you pass will not be searched, only the next one 425 * will; typically, you pass what the previous call 426 * returned. of_node_put() will be called on it 427 * @type: The type string to match "device_type" or NULL to ignore 428 * @compatible: The string to match to one of the tokens in the device 429 * "compatible" list. 430 * 431 * Returns a node pointer with refcount incremented, use 432 * of_node_put() on it when done. 433 */ 434 struct device_node *of_find_compatible_node(struct device_node *from, 435 const char *type, const char *compatible) 436 { 437 struct device_node *np; 438 439 read_lock(&devtree_lock); 440 np = from ? from->allnext : allnodes; 441 for (; np; np = np->allnext) { 442 if (type 443 && !(np->type && (of_node_cmp(np->type, type) == 0))) 444 continue; 445 if (of_device_is_compatible(np, compatible) && of_node_get(np)) 446 break; 447 } 448 of_node_put(from); 449 read_unlock(&devtree_lock); 450 return np; 451 } 452 EXPORT_SYMBOL(of_find_compatible_node); 453 454 /** 455 * of_find_node_with_property - Find a node which has a property with 456 * the given name. 457 * @from: The node to start searching from or NULL, the node 458 * you pass will not be searched, only the next one 459 * will; typically, you pass what the previous call 460 * returned. of_node_put() will be called on it 461 * @prop_name: The name of the property to look for. 462 * 463 * Returns a node pointer with refcount incremented, use 464 * of_node_put() on it when done. 465 */ 466 struct device_node *of_find_node_with_property(struct device_node *from, 467 const char *prop_name) 468 { 469 struct device_node *np; 470 struct property *pp; 471 472 read_lock(&devtree_lock); 473 np = from ? from->allnext : allnodes; 474 for (; np; np = np->allnext) { 475 for (pp = np->properties; pp != 0; pp = pp->next) { 476 if (of_prop_cmp(pp->name, prop_name) == 0) { 477 of_node_get(np); 478 goto out; 479 } 480 } 481 } 482 out: 483 of_node_put(from); 484 read_unlock(&devtree_lock); 485 return np; 486 } 487 EXPORT_SYMBOL(of_find_node_with_property); 488 489 /** 490 * of_match_node - Tell if an device_node has a matching of_match structure 491 * @matches: array of of device match structures to search in 492 * @node: the of device structure to match against 493 * 494 * Low level utility function used by device matching. 495 */ 496 const struct of_device_id *of_match_node(const struct of_device_id *matches, 497 const struct device_node *node) 498 { 499 while (matches->name[0] || matches->type[0] || matches->compatible[0]) { 500 int match = 1; 501 if (matches->name[0]) 502 match &= node->name 503 && !strcmp(matches->name, node->name); 504 if (matches->type[0]) 505 match &= node->type 506 && !strcmp(matches->type, node->type); 507 if (matches->compatible[0]) 508 match &= of_device_is_compatible(node, 509 matches->compatible); 510 if (match) 511 return matches; 512 matches++; 513 } 514 return NULL; 515 } 516 EXPORT_SYMBOL(of_match_node); 517 518 /** 519 * of_find_matching_node - Find a node based on an of_device_id match 520 * table. 521 * @from: The node to start searching from or NULL, the node 522 * you pass will not be searched, only the next one 523 * will; typically, you pass what the previous call 524 * returned. of_node_put() will be called on it 525 * @matches: array of of device match structures to search in 526 * 527 * Returns a node pointer with refcount incremented, use 528 * of_node_put() on it when done. 529 */ 530 struct device_node *of_find_matching_node(struct device_node *from, 531 const struct of_device_id *matches) 532 { 533 struct device_node *np; 534 535 read_lock(&devtree_lock); 536 np = from ? from->allnext : allnodes; 537 for (; np; np = np->allnext) { 538 if (of_match_node(matches, np) && of_node_get(np)) 539 break; 540 } 541 of_node_put(from); 542 read_unlock(&devtree_lock); 543 return np; 544 } 545 EXPORT_SYMBOL(of_find_matching_node); 546 547 /** 548 * of_modalias_node - Lookup appropriate modalias for a device node 549 * @node: pointer to a device tree node 550 * @modalias: Pointer to buffer that modalias value will be copied into 551 * @len: Length of modalias value 552 * 553 * Based on the value of the compatible property, this routine will attempt 554 * to choose an appropriate modalias value for a particular device tree node. 555 * It does this by stripping the manufacturer prefix (as delimited by a ',') 556 * from the first entry in the compatible list property. 557 * 558 * This routine returns 0 on success, <0 on failure. 559 */ 560 int of_modalias_node(struct device_node *node, char *modalias, int len) 561 { 562 const char *compatible, *p; 563 int cplen; 564 565 compatible = of_get_property(node, "compatible", &cplen); 566 if (!compatible || strlen(compatible) > cplen) 567 return -ENODEV; 568 p = strchr(compatible, ','); 569 strlcpy(modalias, p ? p + 1 : compatible, len); 570 return 0; 571 } 572 EXPORT_SYMBOL_GPL(of_modalias_node); 573 574 /** 575 * of_find_node_by_phandle - Find a node given a phandle 576 * @handle: phandle of the node to find 577 * 578 * Returns a node pointer with refcount incremented, use 579 * of_node_put() on it when done. 580 */ 581 struct device_node *of_find_node_by_phandle(phandle handle) 582 { 583 struct device_node *np; 584 585 read_lock(&devtree_lock); 586 for (np = allnodes; np; np = np->allnext) 587 if (np->phandle == handle) 588 break; 589 of_node_get(np); 590 read_unlock(&devtree_lock); 591 return np; 592 } 593 EXPORT_SYMBOL(of_find_node_by_phandle); 594 595 /** 596 * of_parse_phandle - Resolve a phandle property to a device_node pointer 597 * @np: Pointer to device node holding phandle property 598 * @phandle_name: Name of property holding a phandle value 599 * @index: For properties holding a table of phandles, this is the index into 600 * the table 601 * 602 * Returns the device_node pointer with refcount incremented. Use 603 * of_node_put() on it when done. 604 */ 605 struct device_node * 606 of_parse_phandle(struct device_node *np, const char *phandle_name, int index) 607 { 608 const __be32 *phandle; 609 int size; 610 611 phandle = of_get_property(np, phandle_name, &size); 612 if ((!phandle) || (size < sizeof(*phandle) * (index + 1))) 613 return NULL; 614 615 return of_find_node_by_phandle(be32_to_cpup(phandle + index)); 616 } 617 EXPORT_SYMBOL(of_parse_phandle); 618 619 /** 620 * of_parse_phandles_with_args - Find a node pointed by phandle in a list 621 * @np: pointer to a device tree node containing a list 622 * @list_name: property name that contains a list 623 * @cells_name: property name that specifies phandles' arguments count 624 * @index: index of a phandle to parse out 625 * @out_node: optional pointer to device_node struct pointer (will be filled) 626 * @out_args: optional pointer to arguments pointer (will be filled) 627 * 628 * This function is useful to parse lists of phandles and their arguments. 629 * Returns 0 on success and fills out_node and out_args, on error returns 630 * appropriate errno value. 631 * 632 * Example: 633 * 634 * phandle1: node1 { 635 * #list-cells = <2>; 636 * } 637 * 638 * phandle2: node2 { 639 * #list-cells = <1>; 640 * } 641 * 642 * node3 { 643 * list = <&phandle1 1 2 &phandle2 3>; 644 * } 645 * 646 * To get a device_node of the `node2' node you may call this: 647 * of_parse_phandles_with_args(node3, "list", "#list-cells", 2, &node2, &args); 648 */ 649 int of_parse_phandles_with_args(struct device_node *np, const char *list_name, 650 const char *cells_name, int index, 651 struct device_node **out_node, 652 const void **out_args) 653 { 654 int ret = -EINVAL; 655 const __be32 *list; 656 const __be32 *list_end; 657 int size; 658 int cur_index = 0; 659 struct device_node *node = NULL; 660 const void *args = NULL; 661 662 list = of_get_property(np, list_name, &size); 663 if (!list) { 664 ret = -ENOENT; 665 goto err0; 666 } 667 list_end = list + size / sizeof(*list); 668 669 while (list < list_end) { 670 const __be32 *cells; 671 phandle phandle; 672 673 phandle = be32_to_cpup(list++); 674 args = list; 675 676 /* one cell hole in the list = <>; */ 677 if (!phandle) 678 goto next; 679 680 node = of_find_node_by_phandle(phandle); 681 if (!node) { 682 pr_debug("%s: could not find phandle\n", 683 np->full_name); 684 goto err0; 685 } 686 687 cells = of_get_property(node, cells_name, &size); 688 if (!cells || size != sizeof(*cells)) { 689 pr_debug("%s: could not get %s for %s\n", 690 np->full_name, cells_name, node->full_name); 691 goto err1; 692 } 693 694 list += be32_to_cpup(cells); 695 if (list > list_end) { 696 pr_debug("%s: insufficient arguments length\n", 697 np->full_name); 698 goto err1; 699 } 700 next: 701 if (cur_index == index) 702 break; 703 704 of_node_put(node); 705 node = NULL; 706 args = NULL; 707 cur_index++; 708 } 709 710 if (!node) { 711 /* 712 * args w/o node indicates that the loop above has stopped at 713 * the 'hole' cell. Report this differently. 714 */ 715 if (args) 716 ret = -EEXIST; 717 else 718 ret = -ENOENT; 719 goto err0; 720 } 721 722 if (out_node) 723 *out_node = node; 724 if (out_args) 725 *out_args = args; 726 727 return 0; 728 err1: 729 of_node_put(node); 730 err0: 731 pr_debug("%s failed with status %d\n", __func__, ret); 732 return ret; 733 } 734 EXPORT_SYMBOL(of_parse_phandles_with_args); 735 736 /** 737 * prom_add_property - Add a property to a node 738 */ 739 int prom_add_property(struct device_node *np, struct property *prop) 740 { 741 struct property **next; 742 unsigned long flags; 743 744 prop->next = NULL; 745 write_lock_irqsave(&devtree_lock, flags); 746 next = &np->properties; 747 while (*next) { 748 if (strcmp(prop->name, (*next)->name) == 0) { 749 /* duplicate ! don't insert it */ 750 write_unlock_irqrestore(&devtree_lock, flags); 751 return -1; 752 } 753 next = &(*next)->next; 754 } 755 *next = prop; 756 write_unlock_irqrestore(&devtree_lock, flags); 757 758 #ifdef CONFIG_PROC_DEVICETREE 759 /* try to add to proc as well if it was initialized */ 760 if (np->pde) 761 proc_device_tree_add_prop(np->pde, prop); 762 #endif /* CONFIG_PROC_DEVICETREE */ 763 764 return 0; 765 } 766 767 /** 768 * prom_remove_property - Remove a property from a node. 769 * 770 * Note that we don't actually remove it, since we have given out 771 * who-knows-how-many pointers to the data using get-property. 772 * Instead we just move the property to the "dead properties" 773 * list, so it won't be found any more. 774 */ 775 int prom_remove_property(struct device_node *np, struct property *prop) 776 { 777 struct property **next; 778 unsigned long flags; 779 int found = 0; 780 781 write_lock_irqsave(&devtree_lock, flags); 782 next = &np->properties; 783 while (*next) { 784 if (*next == prop) { 785 /* found the node */ 786 *next = prop->next; 787 prop->next = np->deadprops; 788 np->deadprops = prop; 789 found = 1; 790 break; 791 } 792 next = &(*next)->next; 793 } 794 write_unlock_irqrestore(&devtree_lock, flags); 795 796 if (!found) 797 return -ENODEV; 798 799 #ifdef CONFIG_PROC_DEVICETREE 800 /* try to remove the proc node as well */ 801 if (np->pde) 802 proc_device_tree_remove_prop(np->pde, prop); 803 #endif /* CONFIG_PROC_DEVICETREE */ 804 805 return 0; 806 } 807 808 /* 809 * prom_update_property - Update a property in a node. 810 * 811 * Note that we don't actually remove it, since we have given out 812 * who-knows-how-many pointers to the data using get-property. 813 * Instead we just move the property to the "dead properties" list, 814 * and add the new property to the property list 815 */ 816 int prom_update_property(struct device_node *np, 817 struct property *newprop, 818 struct property *oldprop) 819 { 820 struct property **next; 821 unsigned long flags; 822 int found = 0; 823 824 write_lock_irqsave(&devtree_lock, flags); 825 next = &np->properties; 826 while (*next) { 827 if (*next == oldprop) { 828 /* found the node */ 829 newprop->next = oldprop->next; 830 *next = newprop; 831 oldprop->next = np->deadprops; 832 np->deadprops = oldprop; 833 found = 1; 834 break; 835 } 836 next = &(*next)->next; 837 } 838 write_unlock_irqrestore(&devtree_lock, flags); 839 840 if (!found) 841 return -ENODEV; 842 843 #ifdef CONFIG_PROC_DEVICETREE 844 /* try to add to proc as well if it was initialized */ 845 if (np->pde) 846 proc_device_tree_update_prop(np->pde, newprop, oldprop); 847 #endif /* CONFIG_PROC_DEVICETREE */ 848 849 return 0; 850 } 851 852 #if defined(CONFIG_OF_DYNAMIC) 853 /* 854 * Support for dynamic device trees. 855 * 856 * On some platforms, the device tree can be manipulated at runtime. 857 * The routines in this section support adding, removing and changing 858 * device tree nodes. 859 */ 860 861 /** 862 * of_attach_node - Plug a device node into the tree and global list. 863 */ 864 void of_attach_node(struct device_node *np) 865 { 866 unsigned long flags; 867 868 write_lock_irqsave(&devtree_lock, flags); 869 np->sibling = np->parent->child; 870 np->allnext = allnodes; 871 np->parent->child = np; 872 allnodes = np; 873 write_unlock_irqrestore(&devtree_lock, flags); 874 } 875 876 /** 877 * of_detach_node - "Unplug" a node from the device tree. 878 * 879 * The caller must hold a reference to the node. The memory associated with 880 * the node is not freed until its refcount goes to zero. 881 */ 882 void of_detach_node(struct device_node *np) 883 { 884 struct device_node *parent; 885 unsigned long flags; 886 887 write_lock_irqsave(&devtree_lock, flags); 888 889 parent = np->parent; 890 if (!parent) 891 goto out_unlock; 892 893 if (allnodes == np) 894 allnodes = np->allnext; 895 else { 896 struct device_node *prev; 897 for (prev = allnodes; 898 prev->allnext != np; 899 prev = prev->allnext) 900 ; 901 prev->allnext = np->allnext; 902 } 903 904 if (parent->child == np) 905 parent->child = np->sibling; 906 else { 907 struct device_node *prevsib; 908 for (prevsib = np->parent->child; 909 prevsib->sibling != np; 910 prevsib = prevsib->sibling) 911 ; 912 prevsib->sibling = np->sibling; 913 } 914 915 of_node_set_flag(np, OF_DETACHED); 916 917 out_unlock: 918 write_unlock_irqrestore(&devtree_lock, flags); 919 } 920 #endif /* defined(CONFIG_OF_DYNAMIC) */ 921 922