4 * libfdt - Flat Device Tree manipulation
5 * Copyright (C) 2006 David Gibson, IBM Corporation.
7 * libfdt is dual licensed: you can use it either under the terms of
8 * the GPL, or the BSD license, at your option.
10 * a) This library is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of the
13 * License, or (at your option) any later version.
15 * This library is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public
21 * License along with this library; if not, write to the Free
22 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
27 * b) Redistribution and use in source and binary forms, with or
28 * without modification, are permitted provided that the following
31 * 1. Redistributions of source code must retain the above
32 * copyright notice, this list of conditions and the following
34 * 2. Redistributions in binary form must reproduce the above
35 * copyright notice, this list of conditions and the following
36 * disclaimer in the documentation and/or other materials
37 * provided with the distribution.
39 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
40 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
41 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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43 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
44 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
45 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
46 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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51 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
54 #include <libfdt_env.h>
57 #define FDT_FIRST_SUPPORTED_VERSION 0x10
58 #define FDT_LAST_SUPPORTED_VERSION 0x11
60 /* Error codes: informative error codes */
61 #define FDT_ERR_NOTFOUND 1
62 /* FDT_ERR_NOTFOUND: The requested node or property does not exist */
63 #define FDT_ERR_EXISTS 2
64 /* FDT_ERR_EXISTS: Attempted to create a node or property which
66 #define FDT_ERR_NOSPACE 3
67 /* FDT_ERR_NOSPACE: Operation needed to expand the device
68 * tree, but its buffer did not have sufficient space to
69 * contain the expanded tree. Use fdt_open_into() to move the
70 * device tree to a buffer with more space. */
72 /* Error codes: codes for bad parameters */
73 #define FDT_ERR_BADOFFSET 4
74 /* FDT_ERR_BADOFFSET: Function was passed a structure block
75 * offset which is out-of-bounds, or which points to an
76 * unsuitable part of the structure for the operation. */
77 #define FDT_ERR_BADPATH 5
78 /* FDT_ERR_BADPATH: Function was passed a badly formatted path
79 * (e.g. missing a leading / for a function which requires an
81 #define FDT_ERR_BADPHANDLE 6
82 /* FDT_ERR_BADPHANDLE: Function was passed an invalid phandle
83 * value. phandle values of 0 and -1 are not permitted. */
84 #define FDT_ERR_BADSTATE 7
85 /* FDT_ERR_BADSTATE: Function was passed an incomplete device
86 * tree created by the sequential-write functions, which is
87 * not sufficiently complete for the requested operation. */
89 /* Error codes: codes for bad device tree blobs */
90 #define FDT_ERR_TRUNCATED 8
91 /* FDT_ERR_TRUNCATED: Structure block of the given device tree
92 * ends without an FDT_END tag. */
93 #define FDT_ERR_BADMAGIC 9
94 /* FDT_ERR_BADMAGIC: Given "device tree" appears not to be a
95 * device tree at all - it is missing the flattened device
96 * tree magic number. */
97 #define FDT_ERR_BADVERSION 10
98 /* FDT_ERR_BADVERSION: Given device tree has a version which
99 * can't be handled by the requested operation. For
100 * read-write functions, this may mean that fdt_open_into() is
101 * required to convert the tree to the expected version. */
102 #define FDT_ERR_BADSTRUCTURE 11
103 /* FDT_ERR_BADSTRUCTURE: Given device tree has a corrupt
104 * structure block or other serious error (e.g. misnested
105 * nodes, or subnodes preceding properties). */
106 #define FDT_ERR_BADLAYOUT 12
107 /* FDT_ERR_BADLAYOUT: For read-write functions, the given
108 * device tree has it's sub-blocks in an order that the
109 * function can't handle (memory reserve map, then structure,
110 * then strings). Use fdt_open_into() to reorganize the tree
111 * into a form suitable for the read-write operations. */
113 /* "Can't happen" error indicating a bug in libfdt */
114 #define FDT_ERR_INTERNAL 13
115 /* FDT_ERR_INTERNAL: libfdt has failed an internal assertion.
116 * Should never be returned, if it is, it indicates a bug in
119 /* Errors in device tree content */
120 #define FDT_ERR_BADNCELLS 14
121 /* FDT_ERR_BADNCELLS: Device tree has a #address-cells, #size-cells
122 * or similar property with a bad format or value */
124 #define FDT_ERR_BADVALUE 15
125 /* FDT_ERR_BADVALUE: Device tree has a property with an unexpected
126 * value. For example: a property expected to contain a string list
127 * is not NUL-terminated within the length of its value. */
129 #define FDT_ERR_TOODEEP 16
130 /* FDT_ERR_TOODEEP: The depth of a node has exceeded the internal
131 * libfdt limit. This can happen if you have more than
132 * FDT_MAX_DEPTH nested nodes. */
134 #define FDT_ERR_MAX 16
136 /**********************************************************************/
137 /* Low-level functions (you probably don't need these) */
138 /**********************************************************************/
140 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int checklen);
141 static inline void *fdt_offset_ptr_w(void *fdt, int offset, int checklen)
143 return (void *)(uintptr_t)fdt_offset_ptr(fdt, offset, checklen);
146 uint32_t fdt_next_tag(const void *fdt, int offset, int *nextoffset);
148 /**********************************************************************/
149 /* Traversal functions */
150 /**********************************************************************/
152 int fdt_next_node(const void *fdt, int offset, int *depth);
155 * fdt_first_subnode() - get offset of first direct subnode
158 * @offset: Offset of node to check
159 * @return offset of first subnode, or -FDT_ERR_NOTFOUND if there is none
161 int fdt_first_subnode(const void *fdt, int offset);
164 * fdt_next_subnode() - get offset of next direct subnode
166 * After first calling fdt_first_subnode(), call this function repeatedly to
167 * get direct subnodes of a parent node.
170 * @offset: Offset of previous subnode
171 * @return offset of next subnode, or -FDT_ERR_NOTFOUND if there are no more
174 int fdt_next_subnode(const void *fdt, int offset);
177 * fdt_for_each_subnode - iterate over all subnodes of a parent
179 * @node: child node (int, lvalue)
180 * @fdt: FDT blob (const void *)
181 * @parent: parent node (int)
183 * This is actually a wrapper around a for loop and would be used like so:
185 * fdt_for_each_subnode(node, fdt, parent) {
190 * if ((node < 0) && (node != -FDT_ERR_NOT_FOUND)) {
194 * Note that this is implemented as a macro and @node is used as
195 * iterator in the loop. The parent variable be constant or even a
199 #define fdt_for_each_subnode(node, fdt, parent) \
200 for (node = fdt_first_subnode(fdt, parent); \
202 node = fdt_next_subnode(fdt, node))
204 /**********************************************************************/
205 /* General functions */
206 /**********************************************************************/
208 #define fdt_get_header(fdt, field) \
209 (fdt32_to_cpu(((const struct fdt_header *)(fdt))->field))
210 #define fdt_magic(fdt) (fdt_get_header(fdt, magic))
211 #define fdt_totalsize(fdt) (fdt_get_header(fdt, totalsize))
212 #define fdt_off_dt_struct(fdt) (fdt_get_header(fdt, off_dt_struct))
213 #define fdt_off_dt_strings(fdt) (fdt_get_header(fdt, off_dt_strings))
214 #define fdt_off_mem_rsvmap(fdt) (fdt_get_header(fdt, off_mem_rsvmap))
215 #define fdt_version(fdt) (fdt_get_header(fdt, version))
216 #define fdt_last_comp_version(fdt) (fdt_get_header(fdt, last_comp_version))
217 #define fdt_boot_cpuid_phys(fdt) (fdt_get_header(fdt, boot_cpuid_phys))
218 #define fdt_size_dt_strings(fdt) (fdt_get_header(fdt, size_dt_strings))
219 #define fdt_size_dt_struct(fdt) (fdt_get_header(fdt, size_dt_struct))
221 #define __fdt_set_hdr(name) \
222 static inline void fdt_set_##name(void *fdt, uint32_t val) \
224 struct fdt_header *fdth = (struct fdt_header *)fdt; \
225 fdth->name = cpu_to_fdt32(val); \
227 __fdt_set_hdr(magic);
228 __fdt_set_hdr(totalsize);
229 __fdt_set_hdr(off_dt_struct);
230 __fdt_set_hdr(off_dt_strings);
231 __fdt_set_hdr(off_mem_rsvmap);
232 __fdt_set_hdr(version);
233 __fdt_set_hdr(last_comp_version);
234 __fdt_set_hdr(boot_cpuid_phys);
235 __fdt_set_hdr(size_dt_strings);
236 __fdt_set_hdr(size_dt_struct);
240 * fdt_check_header - sanity check a device tree or possible device tree
241 * @fdt: pointer to data which might be a flattened device tree
243 * fdt_check_header() checks that the given buffer contains what
244 * appears to be a flattened device tree with sane information in its
248 * 0, if the buffer appears to contain a valid device tree
250 * -FDT_ERR_BADVERSION,
251 * -FDT_ERR_BADSTATE, standard meanings, as above
253 int fdt_check_header(const void *fdt);
256 * fdt_move - move a device tree around in memory
257 * @fdt: pointer to the device tree to move
258 * @buf: pointer to memory where the device is to be moved
259 * @bufsize: size of the memory space at buf
261 * fdt_move() relocates, if possible, the device tree blob located at
262 * fdt to the buffer at buf of size bufsize. The buffer may overlap
263 * with the existing device tree blob at fdt. Therefore,
264 * fdt_move(fdt, fdt, fdt_totalsize(fdt))
265 * should always succeed.
269 * -FDT_ERR_NOSPACE, bufsize is insufficient to contain the device tree
271 * -FDT_ERR_BADVERSION,
272 * -FDT_ERR_BADSTATE, standard meanings
274 int fdt_move(const void *fdt, void *buf, int bufsize);
276 /**********************************************************************/
277 /* Read-only functions */
278 /**********************************************************************/
281 * fdt_string - retrieve a string from the strings block of a device tree
282 * @fdt: pointer to the device tree blob
283 * @stroffset: offset of the string within the strings block (native endian)
285 * fdt_string() retrieves a pointer to a single string from the
286 * strings block of the device tree blob at fdt.
289 * a pointer to the string, on success
290 * NULL, if stroffset is out of bounds
292 const char *fdt_string(const void *fdt, int stroffset);
295 * fdt_get_max_phandle - retrieves the highest phandle in a tree
296 * @fdt: pointer to the device tree blob
298 * fdt_get_max_phandle retrieves the highest phandle in the given
299 * device tree. This will ignore badly formatted phandles, or phandles
300 * with a value of 0 or -1.
303 * the highest phandle on success
304 * 0, if no phandle was found in the device tree
305 * -1, if an error occurred
307 uint32_t fdt_get_max_phandle(const void *fdt);
310 * fdt_num_mem_rsv - retrieve the number of memory reserve map entries
311 * @fdt: pointer to the device tree blob
313 * Returns the number of entries in the device tree blob's memory
314 * reservation map. This does not include the terminating 0,0 entry
315 * or any other (0,0) entries reserved for expansion.
318 * the number of entries
320 int fdt_num_mem_rsv(const void *fdt);
323 * fdt_get_mem_rsv - retrieve one memory reserve map entry
324 * @fdt: pointer to the device tree blob
325 * @address, @size: pointers to 64-bit variables
327 * On success, *address and *size will contain the address and size of
328 * the n-th reserve map entry from the device tree blob, in
329 * native-endian format.
334 * -FDT_ERR_BADVERSION,
335 * -FDT_ERR_BADSTATE, standard meanings
337 int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size);
340 * fdt_subnode_offset_namelen - find a subnode based on substring
341 * @fdt: pointer to the device tree blob
342 * @parentoffset: structure block offset of a node
343 * @name: name of the subnode to locate
344 * @namelen: number of characters of name to consider
346 * Identical to fdt_subnode_offset(), but only examine the first
347 * namelen characters of name for matching the subnode name. This is
348 * useful for finding subnodes based on a portion of a larger string,
349 * such as a full path.
351 int fdt_subnode_offset_namelen(const void *fdt, int parentoffset,
352 const char *name, int namelen);
354 * fdt_subnode_offset - find a subnode of a given node
355 * @fdt: pointer to the device tree blob
356 * @parentoffset: structure block offset of a node
357 * @name: name of the subnode to locate
359 * fdt_subnode_offset() finds a subnode of the node at structure block
360 * offset parentoffset with the given name. name may include a unit
361 * address, in which case fdt_subnode_offset() will find the subnode
362 * with that unit address, or the unit address may be omitted, in
363 * which case fdt_subnode_offset() will find an arbitrary subnode
364 * whose name excluding unit address matches the given name.
367 * structure block offset of the requested subnode (>=0), on success
368 * -FDT_ERR_NOTFOUND, if the requested subnode does not exist
369 * -FDT_ERR_BADOFFSET, if parentoffset did not point to an FDT_BEGIN_NODE
372 * -FDT_ERR_BADVERSION,
374 * -FDT_ERR_BADSTRUCTURE,
375 * -FDT_ERR_TRUNCATED, standard meanings.
377 int fdt_subnode_offset(const void *fdt, int parentoffset, const char *name);
380 * fdt_path_offset_namelen - find a tree node by its full path
381 * @fdt: pointer to the device tree blob
382 * @path: full path of the node to locate
383 * @namelen: number of characters of path to consider
385 * Identical to fdt_path_offset(), but only consider the first namelen
386 * characters of path as the path name.
388 int fdt_path_offset_namelen(const void *fdt, const char *path, int namelen);
391 * fdt_path_offset - find a tree node by its full path
392 * @fdt: pointer to the device tree blob
393 * @path: full path of the node to locate
395 * fdt_path_offset() finds a node of a given path in the device tree.
396 * Each path component may omit the unit address portion, but the
397 * results of this are undefined if any such path component is
398 * ambiguous (that is if there are multiple nodes at the relevant
399 * level matching the given component, differentiated only by unit
403 * structure block offset of the node with the requested path (>=0), on
405 * -FDT_ERR_BADPATH, given path does not begin with '/' or is invalid
406 * -FDT_ERR_NOTFOUND, if the requested node does not exist
408 * -FDT_ERR_BADVERSION,
410 * -FDT_ERR_BADSTRUCTURE,
411 * -FDT_ERR_TRUNCATED, standard meanings.
413 static inline int fdt_path_offset(const void *fdt, const char *path)
415 return fdt_path_offset_namelen(fdt, path, strlen(path));
419 * fdt_get_name - retrieve the name of a given node
420 * @fdt: pointer to the device tree blob
421 * @nodeoffset: structure block offset of the starting node
422 * @lenp: pointer to an integer variable (will be overwritten) or NULL
424 * fdt_get_name() retrieves the name (including unit address) of the
425 * device tree node at structure block offset nodeoffset. If lenp is
426 * non-NULL, the length of this name is also returned, in the integer
427 * pointed to by lenp.
430 * pointer to the node's name, on success
431 * If lenp is non-NULL, *lenp contains the length of that name
434 * if lenp is non-NULL *lenp contains an error code (<0):
435 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
438 * -FDT_ERR_BADVERSION,
439 * -FDT_ERR_BADSTATE, standard meanings
441 const char *fdt_get_name(const void *fdt, int nodeoffset, int *lenp);
444 * fdt_first_property_offset - find the offset of a node's first property
445 * @fdt: pointer to the device tree blob
446 * @nodeoffset: structure block offset of a node
448 * fdt_first_property_offset() finds the first property of the node at
449 * the given structure block offset.
452 * structure block offset of the property (>=0), on success
453 * -FDT_ERR_NOTFOUND, if the requested node has no properties
454 * -FDT_ERR_BADOFFSET, if nodeoffset did not point to an FDT_BEGIN_NODE tag
456 * -FDT_ERR_BADVERSION,
458 * -FDT_ERR_BADSTRUCTURE,
459 * -FDT_ERR_TRUNCATED, standard meanings.
461 int fdt_first_property_offset(const void *fdt, int nodeoffset);
464 * fdt_next_property_offset - step through a node's properties
465 * @fdt: pointer to the device tree blob
466 * @offset: structure block offset of a property
468 * fdt_next_property_offset() finds the property immediately after the
469 * one at the given structure block offset. This will be a property
470 * of the same node as the given property.
473 * structure block offset of the next property (>=0), on success
474 * -FDT_ERR_NOTFOUND, if the given property is the last in its node
475 * -FDT_ERR_BADOFFSET, if nodeoffset did not point to an FDT_PROP tag
477 * -FDT_ERR_BADVERSION,
479 * -FDT_ERR_BADSTRUCTURE,
480 * -FDT_ERR_TRUNCATED, standard meanings.
482 int fdt_next_property_offset(const void *fdt, int offset);
485 * fdt_for_each_property_offset - iterate over all properties of a node
487 * @property_offset: property offset (int, lvalue)
488 * @fdt: FDT blob (const void *)
489 * @node: node offset (int)
491 * This is actually a wrapper around a for loop and would be used like so:
493 * fdt_for_each_property_offset(property, fdt, node) {
498 * if ((property < 0) && (property != -FDT_ERR_NOT_FOUND)) {
502 * Note that this is implemented as a macro and property is used as
503 * iterator in the loop. The node variable can be constant or even a
506 #define fdt_for_each_property_offset(property, fdt, node) \
507 for (property = fdt_first_property_offset(fdt, node); \
509 property = fdt_next_property_offset(fdt, property))
512 * fdt_get_property_by_offset - retrieve the property at a given offset
513 * @fdt: pointer to the device tree blob
514 * @offset: offset of the property to retrieve
515 * @lenp: pointer to an integer variable (will be overwritten) or NULL
517 * fdt_get_property_by_offset() retrieves a pointer to the
518 * fdt_property structure within the device tree blob at the given
519 * offset. If lenp is non-NULL, the length of the property value is
520 * also returned, in the integer pointed to by lenp.
523 * pointer to the structure representing the property
524 * if lenp is non-NULL, *lenp contains the length of the property
527 * if lenp is non-NULL, *lenp contains an error code (<0):
528 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_PROP tag
530 * -FDT_ERR_BADVERSION,
532 * -FDT_ERR_BADSTRUCTURE,
533 * -FDT_ERR_TRUNCATED, standard meanings
535 const struct fdt_property *fdt_get_property_by_offset(const void *fdt,
540 * fdt_get_property_namelen - find a property based on substring
541 * @fdt: pointer to the device tree blob
542 * @nodeoffset: offset of the node whose property to find
543 * @name: name of the property to find
544 * @namelen: number of characters of name to consider
545 * @lenp: pointer to an integer variable (will be overwritten) or NULL
547 * Identical to fdt_get_property(), but only examine the first namelen
548 * characters of name for matching the property name.
550 const struct fdt_property *fdt_get_property_namelen(const void *fdt,
553 int namelen, int *lenp);
556 * fdt_get_property - find a given property in a given node
557 * @fdt: pointer to the device tree blob
558 * @nodeoffset: offset of the node whose property to find
559 * @name: name of the property to find
560 * @lenp: pointer to an integer variable (will be overwritten) or NULL
562 * fdt_get_property() retrieves a pointer to the fdt_property
563 * structure within the device tree blob corresponding to the property
564 * named 'name' of the node at offset nodeoffset. If lenp is
565 * non-NULL, the length of the property value is also returned, in the
566 * integer pointed to by lenp.
569 * pointer to the structure representing the property
570 * if lenp is non-NULL, *lenp contains the length of the property
573 * if lenp is non-NULL, *lenp contains an error code (<0):
574 * -FDT_ERR_NOTFOUND, node does not have named property
575 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
578 * -FDT_ERR_BADVERSION,
580 * -FDT_ERR_BADSTRUCTURE,
581 * -FDT_ERR_TRUNCATED, standard meanings
583 const struct fdt_property *fdt_get_property(const void *fdt, int nodeoffset,
584 const char *name, int *lenp);
585 static inline struct fdt_property *fdt_get_property_w(void *fdt, int nodeoffset,
589 return (struct fdt_property *)(uintptr_t)
590 fdt_get_property(fdt, nodeoffset, name, lenp);
594 * fdt_getprop_by_offset - retrieve the value of a property at a given offset
595 * @fdt: pointer to the device tree blob
596 * @ffset: offset of the property to read
597 * @namep: pointer to a string variable (will be overwritten) or NULL
598 * @lenp: pointer to an integer variable (will be overwritten) or NULL
600 * fdt_getprop_by_offset() retrieves a pointer to the value of the
601 * property at structure block offset 'offset' (this will be a pointer
602 * to within the device blob itself, not a copy of the value). If
603 * lenp is non-NULL, the length of the property value is also
604 * returned, in the integer pointed to by lenp. If namep is non-NULL,
605 * the property's namne will also be returned in the char * pointed to
606 * by namep (this will be a pointer to within the device tree's string
607 * block, not a new copy of the name).
610 * pointer to the property's value
611 * if lenp is non-NULL, *lenp contains the length of the property
613 * if namep is non-NULL *namep contiains a pointer to the property
616 * if lenp is non-NULL, *lenp contains an error code (<0):
617 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_PROP tag
619 * -FDT_ERR_BADVERSION,
621 * -FDT_ERR_BADSTRUCTURE,
622 * -FDT_ERR_TRUNCATED, standard meanings
624 const void *fdt_getprop_by_offset(const void *fdt, int offset,
625 const char **namep, int *lenp);
628 * fdt_getprop_namelen - get property value based on substring
629 * @fdt: pointer to the device tree blob
630 * @nodeoffset: offset of the node whose property to find
631 * @name: name of the property to find
632 * @namelen: number of characters of name to consider
633 * @lenp: pointer to an integer variable (will be overwritten) or NULL
635 * Identical to fdt_getprop(), but only examine the first namelen
636 * characters of name for matching the property name.
638 const void *fdt_getprop_namelen(const void *fdt, int nodeoffset,
639 const char *name, int namelen, int *lenp);
640 static inline void *fdt_getprop_namelen_w(void *fdt, int nodeoffset,
641 const char *name, int namelen,
644 return (void *)(uintptr_t)fdt_getprop_namelen(fdt, nodeoffset, name,
649 * fdt_getprop - retrieve the value of a given property
650 * @fdt: pointer to the device tree blob
651 * @nodeoffset: offset of the node whose property to find
652 * @name: name of the property to find
653 * @lenp: pointer to an integer variable (will be overwritten) or NULL
655 * fdt_getprop() retrieves a pointer to the value of the property
656 * named 'name' of the node at offset nodeoffset (this will be a
657 * pointer to within the device blob itself, not a copy of the value).
658 * If lenp is non-NULL, the length of the property value is also
659 * returned, in the integer pointed to by lenp.
662 * pointer to the property's value
663 * if lenp is non-NULL, *lenp contains the length of the property
666 * if lenp is non-NULL, *lenp contains an error code (<0):
667 * -FDT_ERR_NOTFOUND, node does not have named property
668 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
671 * -FDT_ERR_BADVERSION,
673 * -FDT_ERR_BADSTRUCTURE,
674 * -FDT_ERR_TRUNCATED, standard meanings
676 const void *fdt_getprop(const void *fdt, int nodeoffset,
677 const char *name, int *lenp);
678 static inline void *fdt_getprop_w(void *fdt, int nodeoffset,
679 const char *name, int *lenp)
681 return (void *)(uintptr_t)fdt_getprop(fdt, nodeoffset, name, lenp);
685 * fdt_get_phandle - retrieve the phandle of a given node
686 * @fdt: pointer to the device tree blob
687 * @nodeoffset: structure block offset of the node
689 * fdt_get_phandle() retrieves the phandle of the device tree node at
690 * structure block offset nodeoffset.
693 * the phandle of the node at nodeoffset, on success (!= 0, != -1)
694 * 0, if the node has no phandle, or another error occurs
696 uint32_t fdt_get_phandle(const void *fdt, int nodeoffset);
699 * fdt_get_alias_namelen - get alias based on substring
700 * @fdt: pointer to the device tree blob
701 * @name: name of the alias th look up
702 * @namelen: number of characters of name to consider
704 * Identical to fdt_get_alias(), but only examine the first namelen
705 * characters of name for matching the alias name.
707 const char *fdt_get_alias_namelen(const void *fdt,
708 const char *name, int namelen);
711 * fdt_get_alias - retrieve the path referenced by a given alias
712 * @fdt: pointer to the device tree blob
713 * @name: name of the alias th look up
715 * fdt_get_alias() retrieves the value of a given alias. That is, the
716 * value of the property named 'name' in the node /aliases.
719 * a pointer to the expansion of the alias named 'name', if it exists
720 * NULL, if the given alias or the /aliases node does not exist
722 const char *fdt_get_alias(const void *fdt, const char *name);
725 * fdt_get_path - determine the full path of a node
726 * @fdt: pointer to the device tree blob
727 * @nodeoffset: offset of the node whose path to find
728 * @buf: character buffer to contain the returned path (will be overwritten)
729 * @buflen: size of the character buffer at buf
731 * fdt_get_path() computes the full path of the node at offset
732 * nodeoffset, and records that path in the buffer at buf.
734 * NOTE: This function is expensive, as it must scan the device tree
735 * structure from the start to nodeoffset.
739 * buf contains the absolute path of the node at
740 * nodeoffset, as a NUL-terminated string.
741 * -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
742 * -FDT_ERR_NOSPACE, the path of the given node is longer than (bufsize-1)
743 * characters and will not fit in the given buffer.
745 * -FDT_ERR_BADVERSION,
747 * -FDT_ERR_BADSTRUCTURE, standard meanings
749 int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen);
752 * fdt_supernode_atdepth_offset - find a specific ancestor of a node
753 * @fdt: pointer to the device tree blob
754 * @nodeoffset: offset of the node whose parent to find
755 * @supernodedepth: depth of the ancestor to find
756 * @nodedepth: pointer to an integer variable (will be overwritten) or NULL
758 * fdt_supernode_atdepth_offset() finds an ancestor of the given node
759 * at a specific depth from the root (where the root itself has depth
760 * 0, its immediate subnodes depth 1 and so forth). So
761 * fdt_supernode_atdepth_offset(fdt, nodeoffset, 0, NULL);
762 * will always return 0, the offset of the root node. If the node at
763 * nodeoffset has depth D, then:
764 * fdt_supernode_atdepth_offset(fdt, nodeoffset, D, NULL);
765 * will return nodeoffset itself.
767 * NOTE: This function is expensive, as it must scan the device tree
768 * structure from the start to nodeoffset.
771 * structure block offset of the node at node offset's ancestor
772 * of depth supernodedepth (>=0), on success
773 * -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
774 * -FDT_ERR_NOTFOUND, supernodedepth was greater than the depth of
777 * -FDT_ERR_BADVERSION,
779 * -FDT_ERR_BADSTRUCTURE, standard meanings
781 int fdt_supernode_atdepth_offset(const void *fdt, int nodeoffset,
782 int supernodedepth, int *nodedepth);
785 * fdt_node_depth - find the depth of a given node
786 * @fdt: pointer to the device tree blob
787 * @nodeoffset: offset of the node whose parent to find
789 * fdt_node_depth() finds the depth of a given node. The root node
790 * has depth 0, its immediate subnodes depth 1 and so forth.
792 * NOTE: This function is expensive, as it must scan the device tree
793 * structure from the start to nodeoffset.
796 * depth of the node at nodeoffset (>=0), on success
797 * -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
799 * -FDT_ERR_BADVERSION,
801 * -FDT_ERR_BADSTRUCTURE, standard meanings
803 int fdt_node_depth(const void *fdt, int nodeoffset);
806 * fdt_parent_offset - find the parent of a given node
807 * @fdt: pointer to the device tree blob
808 * @nodeoffset: offset of the node whose parent to find
810 * fdt_parent_offset() locates the parent node of a given node (that
811 * is, it finds the offset of the node which contains the node at
812 * nodeoffset as a subnode).
814 * NOTE: This function is expensive, as it must scan the device tree
815 * structure from the start to nodeoffset, *twice*.
818 * structure block offset of the parent of the node at nodeoffset
820 * -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
822 * -FDT_ERR_BADVERSION,
824 * -FDT_ERR_BADSTRUCTURE, standard meanings
826 int fdt_parent_offset(const void *fdt, int nodeoffset);
829 * fdt_node_offset_by_prop_value - find nodes with a given property value
830 * @fdt: pointer to the device tree blob
831 * @startoffset: only find nodes after this offset
832 * @propname: property name to check
833 * @propval: property value to search for
834 * @proplen: length of the value in propval
836 * fdt_node_offset_by_prop_value() returns the offset of the first
837 * node after startoffset, which has a property named propname whose
838 * value is of length proplen and has value equal to propval; or if
839 * startoffset is -1, the very first such node in the tree.
841 * To iterate through all nodes matching the criterion, the following
843 * offset = fdt_node_offset_by_prop_value(fdt, -1, propname,
845 * while (offset != -FDT_ERR_NOTFOUND) {
847 * offset = fdt_node_offset_by_prop_value(fdt, offset, propname,
851 * Note the -1 in the first call to the function, if 0 is used here
852 * instead, the function will never locate the root node, even if it
853 * matches the criterion.
856 * structure block offset of the located node (>= 0, >startoffset),
858 * -FDT_ERR_NOTFOUND, no node matching the criterion exists in the
859 * tree after startoffset
860 * -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
862 * -FDT_ERR_BADVERSION,
864 * -FDT_ERR_BADSTRUCTURE, standard meanings
866 int fdt_node_offset_by_prop_value(const void *fdt, int startoffset,
867 const char *propname,
868 const void *propval, int proplen);
871 * fdt_node_offset_by_phandle - find the node with a given phandle
872 * @fdt: pointer to the device tree blob
873 * @phandle: phandle value
875 * fdt_node_offset_by_phandle() returns the offset of the node
876 * which has the given phandle value. If there is more than one node
877 * in the tree with the given phandle (an invalid tree), results are
881 * structure block offset of the located node (>= 0), on success
882 * -FDT_ERR_NOTFOUND, no node with that phandle exists
883 * -FDT_ERR_BADPHANDLE, given phandle value was invalid (0 or -1)
885 * -FDT_ERR_BADVERSION,
887 * -FDT_ERR_BADSTRUCTURE, standard meanings
889 int fdt_node_offset_by_phandle(const void *fdt, uint32_t phandle);
892 * fdt_node_check_compatible: check a node's compatible property
893 * @fdt: pointer to the device tree blob
894 * @nodeoffset: offset of a tree node
895 * @compatible: string to match against
898 * fdt_node_check_compatible() returns 0 if the given node contains a
899 * 'compatible' property with the given string as one of its elements,
900 * it returns non-zero otherwise, or on error.
903 * 0, if the node has a 'compatible' property listing the given string
904 * 1, if the node has a 'compatible' property, but it does not list
906 * -FDT_ERR_NOTFOUND, if the given node has no 'compatible' property
907 * -FDT_ERR_BADOFFSET, if nodeoffset does not refer to a BEGIN_NODE tag
909 * -FDT_ERR_BADVERSION,
911 * -FDT_ERR_BADSTRUCTURE, standard meanings
913 int fdt_node_check_compatible(const void *fdt, int nodeoffset,
914 const char *compatible);
917 * fdt_node_offset_by_compatible - find nodes with a given 'compatible' value
918 * @fdt: pointer to the device tree blob
919 * @startoffset: only find nodes after this offset
920 * @compatible: 'compatible' string to match against
922 * fdt_node_offset_by_compatible() returns the offset of the first
923 * node after startoffset, which has a 'compatible' property which
924 * lists the given compatible string; or if startoffset is -1, the
925 * very first such node in the tree.
927 * To iterate through all nodes matching the criterion, the following
929 * offset = fdt_node_offset_by_compatible(fdt, -1, compatible);
930 * while (offset != -FDT_ERR_NOTFOUND) {
932 * offset = fdt_node_offset_by_compatible(fdt, offset, compatible);
935 * Note the -1 in the first call to the function, if 0 is used here
936 * instead, the function will never locate the root node, even if it
937 * matches the criterion.
940 * structure block offset of the located node (>= 0, >startoffset),
942 * -FDT_ERR_NOTFOUND, no node matching the criterion exists in the
943 * tree after startoffset
944 * -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
946 * -FDT_ERR_BADVERSION,
948 * -FDT_ERR_BADSTRUCTURE, standard meanings
950 int fdt_node_offset_by_compatible(const void *fdt, int startoffset,
951 const char *compatible);
954 * fdt_stringlist_contains - check a string list property for a string
955 * @strlist: Property containing a list of strings to check
956 * @listlen: Length of property
957 * @str: String to search for
959 * This is a utility function provided for convenience. The list contains
960 * one or more strings, each terminated by \0, as is found in a device tree
961 * "compatible" property.
963 * @return: 1 if the string is found in the list, 0 not found, or invalid list
965 int fdt_stringlist_contains(const char *strlist, int listlen, const char *str);
968 * fdt_stringlist_count - count the number of strings in a string list
969 * @fdt: pointer to the device tree blob
970 * @nodeoffset: offset of a tree node
971 * @property: name of the property containing the string list
973 * the number of strings in the given property
974 * -FDT_ERR_BADVALUE if the property value is not NUL-terminated
975 * -FDT_ERR_NOTFOUND if the property does not exist
977 int fdt_stringlist_count(const void *fdt, int nodeoffset, const char *property);
980 * fdt_stringlist_search - find a string in a string list and return its index
981 * @fdt: pointer to the device tree blob
982 * @nodeoffset: offset of a tree node
983 * @property: name of the property containing the string list
984 * @string: string to look up in the string list
986 * Note that it is possible for this function to succeed on property values
987 * that are not NUL-terminated. That's because the function will stop after
988 * finding the first occurrence of @string. This can for example happen with
989 * small-valued cell properties, such as #address-cells, when searching for
993 * the index of the string in the list of strings
994 * -FDT_ERR_BADVALUE if the property value is not NUL-terminated
995 * -FDT_ERR_NOTFOUND if the property does not exist or does not contain
998 int fdt_stringlist_search(const void *fdt, int nodeoffset, const char *property,
1002 * fdt_stringlist_get() - obtain the string at a given index in a string list
1003 * @fdt: pointer to the device tree blob
1004 * @nodeoffset: offset of a tree node
1005 * @property: name of the property containing the string list
1006 * @index: index of the string to return
1007 * @lenp: return location for the string length or an error code on failure
1009 * Note that this will successfully extract strings from properties with
1010 * non-NUL-terminated values. For example on small-valued cell properties
1011 * this function will return the empty string.
1013 * If non-NULL, the length of the string (on success) or a negative error-code
1014 * (on failure) will be stored in the integer pointer to by lenp.
1017 * A pointer to the string at the given index in the string list or NULL on
1018 * failure. On success the length of the string will be stored in the memory
1019 * location pointed to by the lenp parameter, if non-NULL. On failure one of
1020 * the following negative error codes will be returned in the lenp parameter
1022 * -FDT_ERR_BADVALUE if the property value is not NUL-terminated
1023 * -FDT_ERR_NOTFOUND if the property does not exist
1025 const char *fdt_stringlist_get(const void *fdt, int nodeoffset,
1026 const char *property, int index,
1029 /**********************************************************************/
1030 /* Read-only functions (addressing related) */
1031 /**********************************************************************/
1034 * FDT_MAX_NCELLS - maximum value for #address-cells and #size-cells
1036 * This is the maximum value for #address-cells, #size-cells and
1037 * similar properties that will be processed by libfdt. IEE1275
1038 * requires that OF implementations handle values up to 4.
1039 * Implementations may support larger values, but in practice higher
1040 * values aren't used.
1042 #define FDT_MAX_NCELLS 4
1045 * fdt_address_cells - retrieve address size for a bus represented in the tree
1046 * @fdt: pointer to the device tree blob
1047 * @nodeoffset: offset of the node to find the address size for
1049 * When the node has a valid #address-cells property, returns its value.
1052 * 0 <= n < FDT_MAX_NCELLS, on success
1053 * 2, if the node has no #address-cells property
1054 * -FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
1055 * #address-cells property
1056 * -FDT_ERR_BADMAGIC,
1057 * -FDT_ERR_BADVERSION,
1058 * -FDT_ERR_BADSTATE,
1059 * -FDT_ERR_BADSTRUCTURE,
1060 * -FDT_ERR_TRUNCATED, standard meanings
1062 int fdt_address_cells(const void *fdt, int nodeoffset);
1065 * fdt_size_cells - retrieve address range size for a bus represented in the
1067 * @fdt: pointer to the device tree blob
1068 * @nodeoffset: offset of the node to find the address range size for
1070 * When the node has a valid #size-cells property, returns its value.
1073 * 0 <= n < FDT_MAX_NCELLS, on success
1074 * 2, if the node has no #address-cells property
1075 * -FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
1076 * #size-cells property
1077 * -FDT_ERR_BADMAGIC,
1078 * -FDT_ERR_BADVERSION,
1079 * -FDT_ERR_BADSTATE,
1080 * -FDT_ERR_BADSTRUCTURE,
1081 * -FDT_ERR_TRUNCATED, standard meanings
1083 int fdt_size_cells(const void *fdt, int nodeoffset);
1086 /**********************************************************************/
1087 /* Write-in-place functions */
1088 /**********************************************************************/
1091 * fdt_setprop_inplace_namelen_partial - change a property's value,
1093 * @fdt: pointer to the device tree blob
1094 * @nodeoffset: offset of the node whose property to change
1095 * @name: name of the property to change
1096 * @namelen: number of characters of name to consider
1097 * @idx: index of the property to change in the array
1098 * @val: pointer to data to replace the property value with
1099 * @len: length of the property value
1101 * Identical to fdt_setprop_inplace(), but modifies the given property
1102 * starting from the given index, and using only the first characters
1103 * of the name. It is useful when you want to manipulate only one value of
1104 * an array and you have a string that doesn't end with \0.
1106 int fdt_setprop_inplace_namelen_partial(void *fdt, int nodeoffset,
1107 const char *name, int namelen,
1108 uint32_t idx, const void *val,
1112 * fdt_setprop_inplace - change a property's value, but not its size
1113 * @fdt: pointer to the device tree blob
1114 * @nodeoffset: offset of the node whose property to change
1115 * @name: name of the property to change
1116 * @val: pointer to data to replace the property value with
1117 * @len: length of the property value
1119 * fdt_setprop_inplace() replaces the value of a given property with
1120 * the data in val, of length len. This function cannot change the
1121 * size of a property, and so will only work if len is equal to the
1122 * current length of the property.
1124 * This function will alter only the bytes in the blob which contain
1125 * the given property value, and will not alter or move any other part
1130 * -FDT_ERR_NOSPACE, if len is not equal to the property's current length
1131 * -FDT_ERR_NOTFOUND, node does not have the named property
1132 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1133 * -FDT_ERR_BADMAGIC,
1134 * -FDT_ERR_BADVERSION,
1135 * -FDT_ERR_BADSTATE,
1136 * -FDT_ERR_BADSTRUCTURE,
1137 * -FDT_ERR_TRUNCATED, standard meanings
1139 int fdt_setprop_inplace(void *fdt, int nodeoffset, const char *name,
1140 const void *val, int len);
1143 * fdt_setprop_inplace_u32 - change the value of a 32-bit integer property
1144 * @fdt: pointer to the device tree blob
1145 * @nodeoffset: offset of the node whose property to change
1146 * @name: name of the property to change
1147 * @val: 32-bit integer value to replace the property with
1149 * fdt_setprop_inplace_u32() replaces the value of a given property
1150 * with the 32-bit integer value in val, converting val to big-endian
1151 * if necessary. This function cannot change the size of a property,
1152 * and so will only work if the property already exists and has length
1155 * This function will alter only the bytes in the blob which contain
1156 * the given property value, and will not alter or move any other part
1161 * -FDT_ERR_NOSPACE, if the property's length is not equal to 4
1162 * -FDT_ERR_NOTFOUND, node does not have the named property
1163 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1164 * -FDT_ERR_BADMAGIC,
1165 * -FDT_ERR_BADVERSION,
1166 * -FDT_ERR_BADSTATE,
1167 * -FDT_ERR_BADSTRUCTURE,
1168 * -FDT_ERR_TRUNCATED, standard meanings
1170 static inline int fdt_setprop_inplace_u32(void *fdt, int nodeoffset,
1171 const char *name, uint32_t val)
1173 fdt32_t tmp = cpu_to_fdt32(val);
1174 return fdt_setprop_inplace(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1178 * fdt_setprop_inplace_u64 - change the value of a 64-bit integer property
1179 * @fdt: pointer to the device tree blob
1180 * @nodeoffset: offset of the node whose property to change
1181 * @name: name of the property to change
1182 * @val: 64-bit integer value to replace the property with
1184 * fdt_setprop_inplace_u64() replaces the value of a given property
1185 * with the 64-bit integer value in val, converting val to big-endian
1186 * if necessary. This function cannot change the size of a property,
1187 * and so will only work if the property already exists and has length
1190 * This function will alter only the bytes in the blob which contain
1191 * the given property value, and will not alter or move any other part
1196 * -FDT_ERR_NOSPACE, if the property's length is not equal to 8
1197 * -FDT_ERR_NOTFOUND, node does not have the named property
1198 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1199 * -FDT_ERR_BADMAGIC,
1200 * -FDT_ERR_BADVERSION,
1201 * -FDT_ERR_BADSTATE,
1202 * -FDT_ERR_BADSTRUCTURE,
1203 * -FDT_ERR_TRUNCATED, standard meanings
1205 static inline int fdt_setprop_inplace_u64(void *fdt, int nodeoffset,
1206 const char *name, uint64_t val)
1208 fdt64_t tmp = cpu_to_fdt64(val);
1209 return fdt_setprop_inplace(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1213 * fdt_setprop_inplace_cell - change the value of a single-cell property
1215 * This is an alternative name for fdt_setprop_inplace_u32()
1217 static inline int fdt_setprop_inplace_cell(void *fdt, int nodeoffset,
1218 const char *name, uint32_t val)
1220 return fdt_setprop_inplace_u32(fdt, nodeoffset, name, val);
1224 * fdt_nop_property - replace a property with nop tags
1225 * @fdt: pointer to the device tree blob
1226 * @nodeoffset: offset of the node whose property to nop
1227 * @name: name of the property to nop
1229 * fdt_nop_property() will replace a given property's representation
1230 * in the blob with FDT_NOP tags, effectively removing it from the
1233 * This function will alter only the bytes in the blob which contain
1234 * the property, and will not alter or move any other part of the
1239 * -FDT_ERR_NOTFOUND, node does not have the named property
1240 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1241 * -FDT_ERR_BADMAGIC,
1242 * -FDT_ERR_BADVERSION,
1243 * -FDT_ERR_BADSTATE,
1244 * -FDT_ERR_BADSTRUCTURE,
1245 * -FDT_ERR_TRUNCATED, standard meanings
1247 int fdt_nop_property(void *fdt, int nodeoffset, const char *name);
1250 * fdt_nop_node - replace a node (subtree) with nop tags
1251 * @fdt: pointer to the device tree blob
1252 * @nodeoffset: offset of the node to nop
1254 * fdt_nop_node() will replace a given node's representation in the
1255 * blob, including all its subnodes, if any, with FDT_NOP tags,
1256 * effectively removing it from the tree.
1258 * This function will alter only the bytes in the blob which contain
1259 * the node and its properties and subnodes, and will not alter or
1260 * move any other part of the tree.
1264 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1265 * -FDT_ERR_BADMAGIC,
1266 * -FDT_ERR_BADVERSION,
1267 * -FDT_ERR_BADSTATE,
1268 * -FDT_ERR_BADSTRUCTURE,
1269 * -FDT_ERR_TRUNCATED, standard meanings
1271 int fdt_nop_node(void *fdt, int nodeoffset);
1273 /**********************************************************************/
1274 /* Sequential write functions */
1275 /**********************************************************************/
1277 int fdt_create(void *buf, int bufsize);
1278 int fdt_resize(void *fdt, void *buf, int bufsize);
1279 int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size);
1280 int fdt_finish_reservemap(void *fdt);
1281 int fdt_begin_node(void *fdt, const char *name);
1282 int fdt_property(void *fdt, const char *name, const void *val, int len);
1283 static inline int fdt_property_u32(void *fdt, const char *name, uint32_t val)
1285 fdt32_t tmp = cpu_to_fdt32(val);
1286 return fdt_property(fdt, name, &tmp, sizeof(tmp));
1288 static inline int fdt_property_u64(void *fdt, const char *name, uint64_t val)
1290 fdt64_t tmp = cpu_to_fdt64(val);
1291 return fdt_property(fdt, name, &tmp, sizeof(tmp));
1293 static inline int fdt_property_cell(void *fdt, const char *name, uint32_t val)
1295 return fdt_property_u32(fdt, name, val);
1299 * fdt_property_placeholder - add a new property and return a ptr to its value
1301 * @fdt: pointer to the device tree blob
1302 * @name: name of property to add
1303 * @len: length of property value in bytes
1304 * @valp: returns a pointer to where where the value should be placed
1308 * -FDT_ERR_BADMAGIC,
1309 * -FDT_ERR_NOSPACE, standard meanings
1311 int fdt_property_placeholder(void *fdt, const char *name, int len, void **valp);
1313 #define fdt_property_string(fdt, name, str) \
1314 fdt_property(fdt, name, str, strlen(str)+1)
1315 int fdt_end_node(void *fdt);
1316 int fdt_finish(void *fdt);
1318 /**********************************************************************/
1319 /* Read-write functions */
1320 /**********************************************************************/
1322 int fdt_create_empty_tree(void *buf, int bufsize);
1323 int fdt_open_into(const void *fdt, void *buf, int bufsize);
1324 int fdt_pack(void *fdt);
1327 * fdt_add_mem_rsv - add one memory reserve map entry
1328 * @fdt: pointer to the device tree blob
1329 * @address, @size: 64-bit values (native endian)
1331 * Adds a reserve map entry to the given blob reserving a region at
1332 * address address of length size.
1334 * This function will insert data into the reserve map and will
1335 * therefore change the indexes of some entries in the table.
1339 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1340 * contain the new reservation entry
1341 * -FDT_ERR_BADMAGIC,
1342 * -FDT_ERR_BADVERSION,
1343 * -FDT_ERR_BADSTATE,
1344 * -FDT_ERR_BADSTRUCTURE,
1345 * -FDT_ERR_BADLAYOUT,
1346 * -FDT_ERR_TRUNCATED, standard meanings
1348 int fdt_add_mem_rsv(void *fdt, uint64_t address, uint64_t size);
1351 * fdt_del_mem_rsv - remove a memory reserve map entry
1352 * @fdt: pointer to the device tree blob
1353 * @n: entry to remove
1355 * fdt_del_mem_rsv() removes the n-th memory reserve map entry from
1358 * This function will delete data from the reservation table and will
1359 * therefore change the indexes of some entries in the table.
1363 * -FDT_ERR_NOTFOUND, there is no entry of the given index (i.e. there
1364 * are less than n+1 reserve map entries)
1365 * -FDT_ERR_BADMAGIC,
1366 * -FDT_ERR_BADVERSION,
1367 * -FDT_ERR_BADSTATE,
1368 * -FDT_ERR_BADSTRUCTURE,
1369 * -FDT_ERR_BADLAYOUT,
1370 * -FDT_ERR_TRUNCATED, standard meanings
1372 int fdt_del_mem_rsv(void *fdt, int n);
1375 * fdt_set_name - change the name of a given node
1376 * @fdt: pointer to the device tree blob
1377 * @nodeoffset: structure block offset of a node
1378 * @name: name to give the node
1380 * fdt_set_name() replaces the name (including unit address, if any)
1381 * of the given node with the given string. NOTE: this function can't
1382 * efficiently check if the new name is unique amongst the given
1383 * node's siblings; results are undefined if this function is invoked
1384 * with a name equal to one of the given node's siblings.
1386 * This function may insert or delete data from the blob, and will
1387 * therefore change the offsets of some existing nodes.
1391 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob
1392 * to contain the new name
1393 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1394 * -FDT_ERR_BADMAGIC,
1395 * -FDT_ERR_BADVERSION,
1396 * -FDT_ERR_BADSTATE, standard meanings
1398 int fdt_set_name(void *fdt, int nodeoffset, const char *name);
1401 * fdt_setprop - create or change a property
1402 * @fdt: pointer to the device tree blob
1403 * @nodeoffset: offset of the node whose property to change
1404 * @name: name of the property to change
1405 * @val: pointer to data to set the property value to
1406 * @len: length of the property value
1408 * fdt_setprop() sets the value of the named property in the given
1409 * node to the given value and length, creating the property if it
1410 * does not already exist.
1412 * This function may insert or delete data from the blob, and will
1413 * therefore change the offsets of some existing nodes.
1417 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1418 * contain the new property value
1419 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1420 * -FDT_ERR_BADLAYOUT,
1421 * -FDT_ERR_BADMAGIC,
1422 * -FDT_ERR_BADVERSION,
1423 * -FDT_ERR_BADSTATE,
1424 * -FDT_ERR_BADSTRUCTURE,
1425 * -FDT_ERR_BADLAYOUT,
1426 * -FDT_ERR_TRUNCATED, standard meanings
1428 int fdt_setprop(void *fdt, int nodeoffset, const char *name,
1429 const void *val, int len);
1432 * fdt_setprop_u32 - set a property to a 32-bit integer
1433 * @fdt: pointer to the device tree blob
1434 * @nodeoffset: offset of the node whose property to change
1435 * @name: name of the property to change
1436 * @val: 32-bit integer value for the property (native endian)
1438 * fdt_setprop_u32() sets the value of the named property in the given
1439 * node to the given 32-bit integer value (converting to big-endian if
1440 * necessary), or creates a new property with that value if it does
1441 * not already exist.
1443 * This function may insert or delete data from the blob, and will
1444 * therefore change the offsets of some existing nodes.
1448 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1449 * contain the new property value
1450 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1451 * -FDT_ERR_BADLAYOUT,
1452 * -FDT_ERR_BADMAGIC,
1453 * -FDT_ERR_BADVERSION,
1454 * -FDT_ERR_BADSTATE,
1455 * -FDT_ERR_BADSTRUCTURE,
1456 * -FDT_ERR_BADLAYOUT,
1457 * -FDT_ERR_TRUNCATED, standard meanings
1459 static inline int fdt_setprop_u32(void *fdt, int nodeoffset, const char *name,
1462 fdt32_t tmp = cpu_to_fdt32(val);
1463 return fdt_setprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1467 * fdt_setprop_u64 - set a property to a 64-bit integer
1468 * @fdt: pointer to the device tree blob
1469 * @nodeoffset: offset of the node whose property to change
1470 * @name: name of the property to change
1471 * @val: 64-bit integer value for the property (native endian)
1473 * fdt_setprop_u64() sets the value of the named property in the given
1474 * node to the given 64-bit integer value (converting to big-endian if
1475 * necessary), or creates a new property with that value if it does
1476 * not already exist.
1478 * This function may insert or delete data from the blob, and will
1479 * therefore change the offsets of some existing nodes.
1483 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1484 * contain the new property value
1485 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1486 * -FDT_ERR_BADLAYOUT,
1487 * -FDT_ERR_BADMAGIC,
1488 * -FDT_ERR_BADVERSION,
1489 * -FDT_ERR_BADSTATE,
1490 * -FDT_ERR_BADSTRUCTURE,
1491 * -FDT_ERR_BADLAYOUT,
1492 * -FDT_ERR_TRUNCATED, standard meanings
1494 static inline int fdt_setprop_u64(void *fdt, int nodeoffset, const char *name,
1497 fdt64_t tmp = cpu_to_fdt64(val);
1498 return fdt_setprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1502 * fdt_setprop_cell - set a property to a single cell value
1504 * This is an alternative name for fdt_setprop_u32()
1506 static inline int fdt_setprop_cell(void *fdt, int nodeoffset, const char *name,
1509 return fdt_setprop_u32(fdt, nodeoffset, name, val);
1513 * fdt_setprop_string - set a property to a string value
1514 * @fdt: pointer to the device tree blob
1515 * @nodeoffset: offset of the node whose property to change
1516 * @name: name of the property to change
1517 * @str: string value for the property
1519 * fdt_setprop_string() sets the value of the named property in the
1520 * given node to the given string value (using the length of the
1521 * string to determine the new length of the property), or creates a
1522 * new property with that value if it does not already exist.
1524 * This function may insert or delete data from the blob, and will
1525 * therefore change the offsets of some existing nodes.
1529 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1530 * contain the new property value
1531 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1532 * -FDT_ERR_BADLAYOUT,
1533 * -FDT_ERR_BADMAGIC,
1534 * -FDT_ERR_BADVERSION,
1535 * -FDT_ERR_BADSTATE,
1536 * -FDT_ERR_BADSTRUCTURE,
1537 * -FDT_ERR_BADLAYOUT,
1538 * -FDT_ERR_TRUNCATED, standard meanings
1540 #define fdt_setprop_string(fdt, nodeoffset, name, str) \
1541 fdt_setprop((fdt), (nodeoffset), (name), (str), strlen(str)+1)
1544 * fdt_appendprop - append to or create a property
1545 * @fdt: pointer to the device tree blob
1546 * @nodeoffset: offset of the node whose property to change
1547 * @name: name of the property to append to
1548 * @val: pointer to data to append to the property value
1549 * @len: length of the data to append to the property value
1551 * fdt_appendprop() appends the value to the named property in the
1552 * given node, creating the property if it does not already exist.
1554 * This function may insert data into the blob, and will therefore
1555 * change the offsets of some existing nodes.
1559 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1560 * contain the new property value
1561 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1562 * -FDT_ERR_BADLAYOUT,
1563 * -FDT_ERR_BADMAGIC,
1564 * -FDT_ERR_BADVERSION,
1565 * -FDT_ERR_BADSTATE,
1566 * -FDT_ERR_BADSTRUCTURE,
1567 * -FDT_ERR_BADLAYOUT,
1568 * -FDT_ERR_TRUNCATED, standard meanings
1570 int fdt_appendprop(void *fdt, int nodeoffset, const char *name,
1571 const void *val, int len);
1574 * fdt_appendprop_u32 - append a 32-bit integer value to a property
1575 * @fdt: pointer to the device tree blob
1576 * @nodeoffset: offset of the node whose property to change
1577 * @name: name of the property to change
1578 * @val: 32-bit integer value to append to the property (native endian)
1580 * fdt_appendprop_u32() appends the given 32-bit integer value
1581 * (converting to big-endian if necessary) to the value of the named
1582 * property in the given node, or creates a new property with that
1583 * value if it does not already exist.
1585 * This function may insert data into the blob, and will therefore
1586 * change the offsets of some existing nodes.
1590 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1591 * contain the new property value
1592 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1593 * -FDT_ERR_BADLAYOUT,
1594 * -FDT_ERR_BADMAGIC,
1595 * -FDT_ERR_BADVERSION,
1596 * -FDT_ERR_BADSTATE,
1597 * -FDT_ERR_BADSTRUCTURE,
1598 * -FDT_ERR_BADLAYOUT,
1599 * -FDT_ERR_TRUNCATED, standard meanings
1601 static inline int fdt_appendprop_u32(void *fdt, int nodeoffset,
1602 const char *name, uint32_t val)
1604 fdt32_t tmp = cpu_to_fdt32(val);
1605 return fdt_appendprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1609 * fdt_appendprop_u64 - append a 64-bit integer value to a property
1610 * @fdt: pointer to the device tree blob
1611 * @nodeoffset: offset of the node whose property to change
1612 * @name: name of the property to change
1613 * @val: 64-bit integer value to append to the property (native endian)
1615 * fdt_appendprop_u64() appends the given 64-bit integer value
1616 * (converting to big-endian if necessary) to the value of the named
1617 * property in the given node, or creates a new property with that
1618 * value if it does not already exist.
1620 * This function may insert data into the blob, and will therefore
1621 * change the offsets of some existing nodes.
1625 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1626 * contain the new property value
1627 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1628 * -FDT_ERR_BADLAYOUT,
1629 * -FDT_ERR_BADMAGIC,
1630 * -FDT_ERR_BADVERSION,
1631 * -FDT_ERR_BADSTATE,
1632 * -FDT_ERR_BADSTRUCTURE,
1633 * -FDT_ERR_BADLAYOUT,
1634 * -FDT_ERR_TRUNCATED, standard meanings
1636 static inline int fdt_appendprop_u64(void *fdt, int nodeoffset,
1637 const char *name, uint64_t val)
1639 fdt64_t tmp = cpu_to_fdt64(val);
1640 return fdt_appendprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1644 * fdt_appendprop_cell - append a single cell value to a property
1646 * This is an alternative name for fdt_appendprop_u32()
1648 static inline int fdt_appendprop_cell(void *fdt, int nodeoffset,
1649 const char *name, uint32_t val)
1651 return fdt_appendprop_u32(fdt, nodeoffset, name, val);
1655 * fdt_appendprop_string - append a string to a property
1656 * @fdt: pointer to the device tree blob
1657 * @nodeoffset: offset of the node whose property to change
1658 * @name: name of the property to change
1659 * @str: string value to append to the property
1661 * fdt_appendprop_string() appends the given string to the value of
1662 * the named property in the given node, or creates a new property
1663 * with that value if it does not already exist.
1665 * This function may insert data into the blob, and will therefore
1666 * change the offsets of some existing nodes.
1670 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1671 * contain the new property value
1672 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1673 * -FDT_ERR_BADLAYOUT,
1674 * -FDT_ERR_BADMAGIC,
1675 * -FDT_ERR_BADVERSION,
1676 * -FDT_ERR_BADSTATE,
1677 * -FDT_ERR_BADSTRUCTURE,
1678 * -FDT_ERR_BADLAYOUT,
1679 * -FDT_ERR_TRUNCATED, standard meanings
1681 #define fdt_appendprop_string(fdt, nodeoffset, name, str) \
1682 fdt_appendprop((fdt), (nodeoffset), (name), (str), strlen(str)+1)
1685 * fdt_delprop - delete a property
1686 * @fdt: pointer to the device tree blob
1687 * @nodeoffset: offset of the node whose property to nop
1688 * @name: name of the property to nop
1690 * fdt_del_property() will delete the given property.
1692 * This function will delete data from the blob, and will therefore
1693 * change the offsets of some existing nodes.
1697 * -FDT_ERR_NOTFOUND, node does not have the named property
1698 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1699 * -FDT_ERR_BADLAYOUT,
1700 * -FDT_ERR_BADMAGIC,
1701 * -FDT_ERR_BADVERSION,
1702 * -FDT_ERR_BADSTATE,
1703 * -FDT_ERR_BADSTRUCTURE,
1704 * -FDT_ERR_TRUNCATED, standard meanings
1706 int fdt_delprop(void *fdt, int nodeoffset, const char *name);
1709 * fdt_add_subnode_namelen - creates a new node based on substring
1710 * @fdt: pointer to the device tree blob
1711 * @parentoffset: structure block offset of a node
1712 * @name: name of the subnode to locate
1713 * @namelen: number of characters of name to consider
1715 * Identical to fdt_add_subnode(), but use only the first namelen
1716 * characters of name as the name of the new node. This is useful for
1717 * creating subnodes based on a portion of a larger string, such as a
1720 int fdt_add_subnode_namelen(void *fdt, int parentoffset,
1721 const char *name, int namelen);
1724 * fdt_add_subnode - creates a new node
1725 * @fdt: pointer to the device tree blob
1726 * @parentoffset: structure block offset of a node
1727 * @name: name of the subnode to locate
1729 * fdt_add_subnode() creates a new node as a subnode of the node at
1730 * structure block offset parentoffset, with the given name (which
1731 * should include the unit address, if any).
1733 * This function will insert data into the blob, and will therefore
1734 * change the offsets of some existing nodes.
1737 * structure block offset of the created nodeequested subnode (>=0), on
1739 * -FDT_ERR_NOTFOUND, if the requested subnode does not exist
1740 * -FDT_ERR_BADOFFSET, if parentoffset did not point to an FDT_BEGIN_NODE
1742 * -FDT_ERR_EXISTS, if the node at parentoffset already has a subnode of
1744 * -FDT_ERR_NOSPACE, if there is insufficient free space in the
1745 * blob to contain the new node
1747 * -FDT_ERR_BADLAYOUT
1748 * -FDT_ERR_BADMAGIC,
1749 * -FDT_ERR_BADVERSION,
1750 * -FDT_ERR_BADSTATE,
1751 * -FDT_ERR_BADSTRUCTURE,
1752 * -FDT_ERR_TRUNCATED, standard meanings.
1754 int fdt_add_subnode(void *fdt, int parentoffset, const char *name);
1757 * fdt_del_node - delete a node (subtree)
1758 * @fdt: pointer to the device tree blob
1759 * @nodeoffset: offset of the node to nop
1761 * fdt_del_node() will remove the given node, including all its
1762 * subnodes if any, from the blob.
1764 * This function will delete data from the blob, and will therefore
1765 * change the offsets of some existing nodes.
1769 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1770 * -FDT_ERR_BADLAYOUT,
1771 * -FDT_ERR_BADMAGIC,
1772 * -FDT_ERR_BADVERSION,
1773 * -FDT_ERR_BADSTATE,
1774 * -FDT_ERR_BADSTRUCTURE,
1775 * -FDT_ERR_TRUNCATED, standard meanings
1777 int fdt_del_node(void *fdt, int nodeoffset);
1780 * fdt_overlay_apply - Applies a DT overlay on a base DT
1781 * @fdt: pointer to the base device tree blob
1782 * @fdto: pointer to the device tree overlay blob
1784 * fdt_overlay_apply() will apply the given device tree overlay on the
1785 * given base device tree.
1787 * Expect the base device tree to be modified, even if the function
1792 * -FDT_ERR_NOSPACE, there's not enough space in the base device tree
1793 * -FDT_ERR_NOTFOUND, the overlay points to some inexistant nodes or
1794 * properties in the base DT
1795 * -FDT_ERR_BADPHANDLE, the phandles in the overlay do not have the right
1797 * -FDT_ERR_INTERNAL,
1798 * -FDT_ERR_BADLAYOUT,
1799 * -FDT_ERR_BADMAGIC,
1800 * -FDT_ERR_BADOFFSET,
1802 * -FDT_ERR_BADVERSION,
1803 * -FDT_ERR_BADSTRUCTURE,
1804 * -FDT_ERR_BADSTATE,
1805 * -FDT_ERR_TRUNCATED, standard meanings
1807 int fdt_overlay_apply(void *fdt, void *fdto);
1809 /**********************************************************************/
1810 /* Debugging / informational functions */
1811 /**********************************************************************/
1813 const char *fdt_strerror(int errval);
1816 * fdt_remove_unused_strings() - Remove any unused strings from an FDT
1818 * This creates a new device tree in @new with unused strings removed. The
1819 * called can then use fdt_pack() to minimise the space consumed.
1821 * @old: Old device tree blog
1822 * @new: Place to put new device tree blob, which must be as large as
1826 * -FDT_ERR_BADOFFSET, corrupt device tree
1827 * -FDT_ERR_NOSPACE, out of space, which should not happen unless there
1828 * is something very wrong with the device tree input
1830 int fdt_remove_unused_strings(const void *old, void *new);
1838 * Flags for fdt_find_regions()
1840 * Add a region for the string table (always the last region)
1842 #define FDT_REG_ADD_STRING_TAB (1 << 0)
1845 * Add all supernodes of a matching node/property, useful for creating a
1848 #define FDT_REG_SUPERNODES (1 << 1)
1850 /* Add the FDT_BEGIN_NODE tags of subnodes, including their names */
1851 #define FDT_REG_DIRECT_SUBNODES (1 << 2)
1853 /* Add all subnodes of a matching node */
1854 #define FDT_REG_ALL_SUBNODES (1 << 3)
1856 /* Add a region for the mem_rsvmap table (always the first region) */
1857 #define FDT_REG_ADD_MEM_RSVMAP (1 << 4)
1859 /* Indicates what an fdt part is (node, property, value) */
1860 #define FDT_IS_NODE (1 << 0)
1861 #define FDT_IS_PROP (1 << 1)
1862 #define FDT_IS_VALUE (1 << 2) /* not supported */
1863 #define FDT_IS_COMPAT (1 << 3) /* used internally */
1864 #define FDT_NODE_HAS_PROP (1 << 4) /* node contains prop */
1866 #define FDT_ANY_GLOBAL (FDT_IS_NODE | FDT_IS_PROP | FDT_IS_VALUE | \
1868 #define FDT_IS_ANY 0x1f /* all the above */
1870 /* We set a reasonable limit on the number of nested nodes */
1871 #define FDT_MAX_DEPTH 32
1873 /* Decribes what we want to include from the current tag */
1876 WANT_NODES_ONLY, /* No properties */
1877 WANT_NODES_AND_PROPS, /* Everything for one level */
1878 WANT_ALL_NODES_AND_PROPS /* Everything for all levels */
1881 /* Keeps track of the state at parent nodes */
1882 struct fdt_subnode_stack {
1883 int offset; /* Offset of node */
1884 enum want_t want; /* The 'want' value here */
1885 int included; /* 1 if we included this node, 0 if not */
1888 struct fdt_region_ptrs {
1889 int depth; /* Current tree depth */
1890 int done; /* What we have completed scanning */
1891 enum want_t want; /* What we are currently including */
1892 char *end; /* Pointer to end of full node path */
1893 int nextoffset; /* Next node offset to check */
1896 /* The state of our finding algortihm */
1897 struct fdt_region_state {
1898 struct fdt_subnode_stack stack[FDT_MAX_DEPTH]; /* node stack */
1899 struct fdt_region *region; /* Contains list of regions found */
1900 int count; /* Numnber of regions found */
1901 const void *fdt; /* FDT blob */
1902 int max_regions; /* Maximum regions to find */
1903 int can_merge; /* 1 if we can merge with previous region */
1904 int start; /* Start position of current region */
1905 struct fdt_region_ptrs ptrs; /* Pointers for what we are up to */
1909 * fdt_find_regions() - find regions in device tree
1911 * Given a list of nodes to include and properties to exclude, find
1912 * the regions of the device tree which describe those included parts.
1914 * The intent is to get a list of regions which will be invariant provided
1915 * those parts are invariant. For example, if you request a list of regions
1916 * for all nodes but exclude the property "data", then you will get the
1917 * same region contents regardless of any change to "data" properties.
1919 * This function can be used to produce a byte-stream to send to a hashing
1920 * function to verify that critical parts of the FDT have not changed.
1922 * Nodes which are given in 'inc' are included in the region list, as
1923 * are the names of the immediate subnodes nodes (but not the properties
1924 * or subnodes of those subnodes).
1926 * For eaxample "/" means to include the root node, all root properties
1927 * and the FDT_BEGIN_NODE and FDT_END_NODE of all subnodes of /. The latter
1928 * ensures that we capture the names of the subnodes. In a hashing situation
1929 * it prevents the root node from changing at all Any change to non-excluded
1930 * properties, names of subnodes or number of subnodes would be detected.
1932 * When used with FITs this provides the ability to hash and sign parts of
1933 * the FIT based on different configurations in the FIT. Then it is
1934 * impossible to change anything about that configuration (include images
1935 * attached to the configuration), but it may be possible to add new
1936 * configurations, new images or new signatures within the existing
1939 * Adding new properties to a device tree may result in the string table
1940 * being extended (if the new property names are different from those
1941 * already added). This function can optionally include a region for
1942 * the string table so that this can be part of the hash too.
1944 * The device tree header is not included in the list.
1946 * @fdt: Device tree to check
1947 * @inc: List of node paths to included
1948 * @inc_count: Number of node paths in list
1949 * @exc_prop: List of properties names to exclude
1950 * @exc_prop_count: Number of properties in exclude list
1951 * @region: Returns list of regions
1952 * @max_region: Maximum length of region list
1953 * @path: Pointer to a temporary string for the function to use for
1954 * building path names
1955 * @path_len: Length of path, must be large enough to hold the longest
1957 * @add_string_tab: 1 to add a region for the string table
1958 * @return number of regions in list. If this is >max_regions then the
1959 * region array was exhausted. You should increase max_regions and try
1962 int fdt_find_regions(const void *fdt, char * const inc[], int inc_count,
1963 char * const exc_prop[], int exc_prop_count,
1964 struct fdt_region region[], int max_regions,
1965 char *path, int path_len, int add_string_tab);
1968 * fdt_first_region() - find regions in device tree
1970 * Given a nodes and properties to include and properties to exclude, find
1971 * the regions of the device tree which describe those included parts.
1973 * The use for this function is twofold. Firstly it provides a convenient
1974 * way of performing a structure-aware grep of the tree. For example it is
1975 * possible to grep for a node and get all the properties associated with
1976 * that node. Trees can be subsetted easily, by specifying the nodes that
1977 * are required, and then writing out the regions returned by this function.
1978 * This is useful for small resource-constrained systems, such as boot
1979 * loaders, which want to use an FDT but do not need to know about all of
1982 * Secondly it makes it easy to hash parts of the tree and detect changes.
1983 * The intent is to get a list of regions which will be invariant provided
1984 * those parts are invariant. For example, if you request a list of regions
1985 * for all nodes but exclude the property "data", then you will get the
1986 * same region contents regardless of any change to "data" properties.
1988 * This function can be used to produce a byte-stream to send to a hashing
1989 * function to verify that critical parts of the FDT have not changed.
1990 * Note that semantically null changes in order could still cause false
1991 * hash misses. Such reordering might happen if the tree is regenerated
1992 * from source, and nodes are reordered (the bytes-stream will be emitted
1993 * in a different order and mnay hash functions will detect this). However
1994 * if an existing tree is modified using libfdt functions, such as
1995 * fdt_add_subnode() and fdt_setprop(), then this problem is avoided.
1997 * The nodes/properties to include/exclude are defined by a function
1998 * provided by the caller. This function is called for each node and
1999 * property, and must return:
2001 * 0 - to exclude this part
2002 * 1 - to include this part
2003 * -1 - for FDT_IS_PROP only: no information is available, so include
2004 * if its containing node is included
2006 * The last case is only used to deal with properties. Often a property is
2007 * included if its containing node is included - this is the case where
2008 * -1 is returned.. However if the property is specifically required to be
2009 * included/excluded, then 0 or 1 can be returned. Note that including a
2010 * property when the FDT_REG_SUPERNODES flag is given will force its
2011 * containing node to be included since it is not valid to have a property
2012 * that is not in a node.
2014 * Using the information provided, the inclusion of a node can be controlled
2015 * either by a node name or its compatible string, or any other property
2016 * that the function can determine.
2018 * As an example, including node "/" means to include the root node and all
2019 * root properties. A flag provides a way of also including supernodes (of
2020 * which there is none for the root node), and another flag includes
2021 * immediate subnodes, so in this case we would get the FDT_BEGIN_NODE and
2022 * FDT_END_NODE of all subnodes of /.
2024 * The subnode feature helps in a hashing situation since it prevents the
2025 * root node from changing at all. Any change to non-excluded properties,
2026 * names of subnodes or number of subnodes would be detected.
2028 * When used with FITs this provides the ability to hash and sign parts of
2029 * the FIT based on different configurations in the FIT. Then it is
2030 * impossible to change anything about that configuration (include images
2031 * attached to the configuration), but it may be possible to add new
2032 * configurations, new images or new signatures within the existing
2035 * Adding new properties to a device tree may result in the string table
2036 * being extended (if the new property names are different from those
2037 * already added). This function can optionally include a region for
2038 * the string table so that this can be part of the hash too. This is always
2041 * The FDT also has a mem_rsvmap table which can also be included, and is
2042 * always the first region if so.
2044 * The device tree header is not included in the region list. Since the
2045 * contents of the FDT are changing (shrinking, often), the caller will need
2046 * to regenerate the header anyway.
2048 * @fdt: Device tree to check
2049 * @h_include: Function to call to determine whether to include a part or
2052 * @priv: Private pointer as passed to fdt_find_regions()
2053 * @fdt: Pointer to FDT blob
2054 * @offset: Offset of this node / property
2055 * @type: Type of this part, FDT_IS_...
2056 * @data: Pointer to data (node name, property name, compatible
2057 * string, value (not yet supported)
2058 * @size: Size of data, or 0 if none
2059 * @return 0 to exclude, 1 to include, -1 if no information is
2061 * @priv: Private pointer passed to h_include
2062 * @region: Returns list of regions, sorted by offset
2063 * @max_regions: Maximum length of region list
2064 * @path: Pointer to a temporary string for the function to use for
2065 * building path names
2066 * @path_len: Length of path, must be large enough to hold the longest
2068 * @flags: Various flags that control the region algortihm, see
2070 * @return number of regions in list. If this is >max_regions then the
2071 * region array was exhausted. You should increase max_regions and try
2072 * the call again. Only the first max_regions elements are available in the
2075 * On error a -ve value is return, which can be:
2077 * -FDT_ERR_BADSTRUCTURE (too deep or more END tags than BEGIN tags
2078 * -FDT_ERR_BADLAYOUT
2079 * -FDT_ERR_NOSPACE (path area is too small)
2081 int fdt_first_region(const void *fdt,
2082 int (*h_include)(void *priv, const void *fdt, int offset,
2083 int type, const char *data, int size),
2084 void *priv, struct fdt_region *region,
2085 char *path, int path_len, int flags,
2086 struct fdt_region_state *info);
2088 /** fdt_next_region() - find next region
2090 * See fdt_first_region() for full description. This function finds the
2091 * next region according to the provided parameters, which must be the same
2092 * as passed to fdt_first_region().
2094 * This function can additionally return -FDT_ERR_NOTFOUND when there are no
2097 int fdt_next_region(const void *fdt,
2098 int (*h_include)(void *priv, const void *fdt, int offset,
2099 int type, const char *data, int size),
2100 void *priv, struct fdt_region *region,
2101 char *path, int path_len, int flags,
2102 struct fdt_region_state *info);
2105 * fdt_add_alias_regions() - find aliases that point to existing regions
2107 * Once a device tree grep is complete some of the nodes will be present
2108 * and some will have been dropped. This function checks all the alias nodes
2109 * to figure out which points point to nodes which are still present. These
2110 * aliases need to be kept, along with the nodes they reference.
2112 * Given a list of regions function finds the aliases that still apply and
2113 * adds more regions to the list for these. This function is called after
2114 * fdt_next_region() has finished returning regions and requires the same
2117 * @fdt: Device tree file to reference
2118 * @region: List of regions that will be kept
2119 * @count: Number of regions
2120 * @max_regions: Number of entries that can fit in @region
2121 * @info: Region state as returned from fdt_next_region()
2122 * @return new number of regions in @region (i.e. count + the number added)
2123 * or -FDT_ERR_NOSPACE if there was not enough space.
2125 int fdt_add_alias_regions(const void *fdt, struct fdt_region *region, int count,
2126 int max_regions, struct fdt_region_state *info);
2128 #endif /* _LIBFDT_H */