4 * libfdt - Flat Device Tree manipulation
5 * Copyright (C) 2006 David Gibson, IBM Corporation.
7 * SPDX-License-Identifier: GPL-2.0+ BSD-2-Clause
10 #include <libfdt_env.h>
13 #define FDT_FIRST_SUPPORTED_VERSION 0x10
14 #define FDT_LAST_SUPPORTED_VERSION 0x11
16 /* Error codes: informative error codes */
17 #define FDT_ERR_NOTFOUND 1
18 /* FDT_ERR_NOTFOUND: The requested node or property does not exist */
19 #define FDT_ERR_EXISTS 2
20 /* FDT_ERR_EXISTS: Attempted to create a node or property which
22 #define FDT_ERR_NOSPACE 3
23 /* FDT_ERR_NOSPACE: Operation needed to expand the device
24 * tree, but its buffer did not have sufficient space to
25 * contain the expanded tree. Use fdt_open_into() to move the
26 * device tree to a buffer with more space. */
28 /* Error codes: codes for bad parameters */
29 #define FDT_ERR_BADOFFSET 4
30 /* FDT_ERR_BADOFFSET: Function was passed a structure block
31 * offset which is out-of-bounds, or which points to an
32 * unsuitable part of the structure for the operation. */
33 #define FDT_ERR_BADPATH 5
34 /* FDT_ERR_BADPATH: Function was passed a badly formatted path
35 * (e.g. missing a leading / for a function which requires an
37 #define FDT_ERR_BADPHANDLE 6
38 /* FDT_ERR_BADPHANDLE: Function was passed an invalid phandle.
39 * This can be caused either by an invalid phandle property
40 * length, or the phandle value was either 0 or -1, which are
42 #define FDT_ERR_BADSTATE 7
43 /* FDT_ERR_BADSTATE: Function was passed an incomplete device
44 * tree created by the sequential-write functions, which is
45 * not sufficiently complete for the requested operation. */
47 /* Error codes: codes for bad device tree blobs */
48 #define FDT_ERR_TRUNCATED 8
49 /* FDT_ERR_TRUNCATED: Structure block of the given device tree
50 * ends without an FDT_END tag. */
51 #define FDT_ERR_BADMAGIC 9
52 /* FDT_ERR_BADMAGIC: Given "device tree" appears not to be a
53 * device tree at all - it is missing the flattened device
54 * tree magic number. */
55 #define FDT_ERR_BADVERSION 10
56 /* FDT_ERR_BADVERSION: Given device tree has a version which
57 * can't be handled by the requested operation. For
58 * read-write functions, this may mean that fdt_open_into() is
59 * required to convert the tree to the expected version. */
60 #define FDT_ERR_BADSTRUCTURE 11
61 /* FDT_ERR_BADSTRUCTURE: Given device tree has a corrupt
62 * structure block or other serious error (e.g. misnested
63 * nodes, or subnodes preceding properties). */
64 #define FDT_ERR_BADLAYOUT 12
65 /* FDT_ERR_BADLAYOUT: For read-write functions, the given
66 * device tree has it's sub-blocks in an order that the
67 * function can't handle (memory reserve map, then structure,
68 * then strings). Use fdt_open_into() to reorganize the tree
69 * into a form suitable for the read-write operations. */
71 /* "Can't happen" error indicating a bug in libfdt */
72 #define FDT_ERR_INTERNAL 13
73 /* FDT_ERR_INTERNAL: libfdt has failed an internal assertion.
74 * Should never be returned, if it is, it indicates a bug in
77 /* Errors in device tree content */
78 #define FDT_ERR_BADNCELLS 14
79 /* FDT_ERR_BADNCELLS: Device tree has a #address-cells, #size-cells
80 * or similar property with a bad format or value */
82 #define FDT_ERR_BADVALUE 15
83 /* FDT_ERR_BADVALUE: Device tree has a property with an unexpected
84 * value. For example: a property expected to contain a string list
85 * is not NUL-terminated within the length of its value. */
87 #define FDT_ERR_BADOVERLAY 16
88 /* FDT_ERR_BADOVERLAY: The device tree overlay, while
89 * correctly structured, cannot be applied due to some
90 * unexpected or missing value, property or node. */
92 #define FDT_ERR_NOPHANDLES 17
93 /* FDT_ERR_NOPHANDLES: The device tree doesn't have any
94 * phandle available anymore without causing an overflow */
96 #define FDT_ERR_TOODEEP 18
97 /* FDT_ERR_TOODEEP: The depth of a node has exceeded the internal
98 * libfdt limit. This can happen if you have more than
99 * FDT_MAX_DEPTH nested nodes. */
101 #define FDT_ERR_MAX 18
103 /**********************************************************************/
104 /* Low-level functions (you probably don't need these) */
105 /**********************************************************************/
107 #ifndef SWIG /* This function is not useful in Python */
108 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int checklen);
110 static inline void *fdt_offset_ptr_w(void *fdt, int offset, int checklen)
112 return (void *)(uintptr_t)fdt_offset_ptr(fdt, offset, checklen);
115 uint32_t fdt_next_tag(const void *fdt, int offset, int *nextoffset);
117 /**********************************************************************/
118 /* Traversal functions */
119 /**********************************************************************/
121 int fdt_next_node(const void *fdt, int offset, int *depth);
124 * fdt_first_subnode() - get offset of first direct subnode
127 * @offset: Offset of node to check
128 * @return offset of first subnode, or -FDT_ERR_NOTFOUND if there is none
130 int fdt_first_subnode(const void *fdt, int offset);
133 * fdt_next_subnode() - get offset of next direct subnode
135 * After first calling fdt_first_subnode(), call this function repeatedly to
136 * get direct subnodes of a parent node.
139 * @offset: Offset of previous subnode
140 * @return offset of next subnode, or -FDT_ERR_NOTFOUND if there are no more
143 int fdt_next_subnode(const void *fdt, int offset);
146 * fdt_for_each_subnode - iterate over all subnodes of a parent
148 * @node: child node (int, lvalue)
149 * @fdt: FDT blob (const void *)
150 * @parent: parent node (int)
152 * This is actually a wrapper around a for loop and would be used like so:
154 * fdt_for_each_subnode(node, fdt, parent) {
159 * if ((node < 0) && (node != -FDT_ERR_NOT_FOUND)) {
163 * Note that this is implemented as a macro and @node is used as
164 * iterator in the loop. The parent variable be constant or even a
168 #define fdt_for_each_subnode(node, fdt, parent) \
169 for (node = fdt_first_subnode(fdt, parent); \
171 node = fdt_next_subnode(fdt, node))
173 /**********************************************************************/
174 /* General functions */
175 /**********************************************************************/
176 #define fdt_get_header(fdt, field) \
177 (fdt32_to_cpu(((const struct fdt_header *)(fdt))->field))
178 #define fdt_magic(fdt) (fdt_get_header(fdt, magic))
179 #define fdt_totalsize(fdt) (fdt_get_header(fdt, totalsize))
180 #define fdt_off_dt_struct(fdt) (fdt_get_header(fdt, off_dt_struct))
181 #define fdt_off_dt_strings(fdt) (fdt_get_header(fdt, off_dt_strings))
182 #define fdt_off_mem_rsvmap(fdt) (fdt_get_header(fdt, off_mem_rsvmap))
183 #define fdt_version(fdt) (fdt_get_header(fdt, version))
184 #define fdt_last_comp_version(fdt) (fdt_get_header(fdt, last_comp_version))
185 #define fdt_boot_cpuid_phys(fdt) (fdt_get_header(fdt, boot_cpuid_phys))
186 #define fdt_size_dt_strings(fdt) (fdt_get_header(fdt, size_dt_strings))
187 #define fdt_size_dt_struct(fdt) (fdt_get_header(fdt, size_dt_struct))
189 #define __fdt_set_hdr(name) \
190 static inline void fdt_set_##name(void *fdt, uint32_t val) \
192 struct fdt_header *fdth = (struct fdt_header *)fdt; \
193 fdth->name = cpu_to_fdt32(val); \
195 __fdt_set_hdr(magic);
196 __fdt_set_hdr(totalsize);
197 __fdt_set_hdr(off_dt_struct);
198 __fdt_set_hdr(off_dt_strings);
199 __fdt_set_hdr(off_mem_rsvmap);
200 __fdt_set_hdr(version);
201 __fdt_set_hdr(last_comp_version);
202 __fdt_set_hdr(boot_cpuid_phys);
203 __fdt_set_hdr(size_dt_strings);
204 __fdt_set_hdr(size_dt_struct);
208 * fdt_check_header - sanity check a device tree or possible device tree
209 * @fdt: pointer to data which might be a flattened device tree
211 * fdt_check_header() checks that the given buffer contains what
212 * appears to be a flattened device tree with sane information in its
216 * 0, if the buffer appears to contain a valid device tree
218 * -FDT_ERR_BADVERSION,
219 * -FDT_ERR_BADSTATE, standard meanings, as above
221 int fdt_check_header(const void *fdt);
224 * fdt_move - move a device tree around in memory
225 * @fdt: pointer to the device tree to move
226 * @buf: pointer to memory where the device is to be moved
227 * @bufsize: size of the memory space at buf
229 * fdt_move() relocates, if possible, the device tree blob located at
230 * fdt to the buffer at buf of size bufsize. The buffer may overlap
231 * with the existing device tree blob at fdt. Therefore,
232 * fdt_move(fdt, fdt, fdt_totalsize(fdt))
233 * should always succeed.
237 * -FDT_ERR_NOSPACE, bufsize is insufficient to contain the device tree
239 * -FDT_ERR_BADVERSION,
240 * -FDT_ERR_BADSTATE, standard meanings
242 int fdt_move(const void *fdt, void *buf, int bufsize);
244 /**********************************************************************/
245 /* Read-only functions */
246 /**********************************************************************/
249 * fdt_string - retrieve a string from the strings block of a device tree
250 * @fdt: pointer to the device tree blob
251 * @stroffset: offset of the string within the strings block (native endian)
253 * fdt_string() retrieves a pointer to a single string from the
254 * strings block of the device tree blob at fdt.
257 * a pointer to the string, on success
258 * NULL, if stroffset is out of bounds
260 const char *fdt_string(const void *fdt, int stroffset);
263 * fdt_get_max_phandle - retrieves the highest phandle in a tree
264 * @fdt: pointer to the device tree blob
266 * fdt_get_max_phandle retrieves the highest phandle in the given
267 * device tree. This will ignore badly formatted phandles, or phandles
268 * with a value of 0 or -1.
271 * the highest phandle on success
272 * 0, if no phandle was found in the device tree
273 * -1, if an error occurred
275 uint32_t fdt_get_max_phandle(const void *fdt);
278 * fdt_num_mem_rsv - retrieve the number of memory reserve map entries
279 * @fdt: pointer to the device tree blob
281 * Returns the number of entries in the device tree blob's memory
282 * reservation map. This does not include the terminating 0,0 entry
283 * or any other (0,0) entries reserved for expansion.
286 * the number of entries
288 int fdt_num_mem_rsv(const void *fdt);
291 * fdt_get_mem_rsv - retrieve one memory reserve map entry
292 * @fdt: pointer to the device tree blob
293 * @address, @size: pointers to 64-bit variables
295 * On success, *address and *size will contain the address and size of
296 * the n-th reserve map entry from the device tree blob, in
297 * native-endian format.
302 * -FDT_ERR_BADVERSION,
303 * -FDT_ERR_BADSTATE, standard meanings
305 int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size);
308 * fdt_subnode_offset_namelen - find a subnode based on substring
309 * @fdt: pointer to the device tree blob
310 * @parentoffset: structure block offset of a node
311 * @name: name of the subnode to locate
312 * @namelen: number of characters of name to consider
314 * Identical to fdt_subnode_offset(), but only examine the first
315 * namelen characters of name for matching the subnode name. This is
316 * useful for finding subnodes based on a portion of a larger string,
317 * such as a full path.
319 #ifndef SWIG /* Not available in Python */
320 int fdt_subnode_offset_namelen(const void *fdt, int parentoffset,
321 const char *name, int namelen);
324 * fdt_subnode_offset - find a subnode of a given node
325 * @fdt: pointer to the device tree blob
326 * @parentoffset: structure block offset of a node
327 * @name: name of the subnode to locate
329 * fdt_subnode_offset() finds a subnode of the node at structure block
330 * offset parentoffset with the given name. name may include a unit
331 * address, in which case fdt_subnode_offset() will find the subnode
332 * with that unit address, or the unit address may be omitted, in
333 * which case fdt_subnode_offset() will find an arbitrary subnode
334 * whose name excluding unit address matches the given name.
337 * structure block offset of the requested subnode (>=0), on success
338 * -FDT_ERR_NOTFOUND, if the requested subnode does not exist
339 * -FDT_ERR_BADOFFSET, if parentoffset did not point to an FDT_BEGIN_NODE
342 * -FDT_ERR_BADVERSION,
344 * -FDT_ERR_BADSTRUCTURE,
345 * -FDT_ERR_TRUNCATED, standard meanings.
347 int fdt_subnode_offset(const void *fdt, int parentoffset, const char *name);
350 * fdt_path_offset_namelen - find a tree node by its full path
351 * @fdt: pointer to the device tree blob
352 * @path: full path of the node to locate
353 * @namelen: number of characters of path to consider
355 * Identical to fdt_path_offset(), but only consider the first namelen
356 * characters of path as the path name.
358 #ifndef SWIG /* Not available in Python */
359 int fdt_path_offset_namelen(const void *fdt, const char *path, int namelen);
363 * fdt_path_offset - find a tree node by its full path
364 * @fdt: pointer to the device tree blob
365 * @path: full path of the node to locate
367 * fdt_path_offset() finds a node of a given path in the device tree.
368 * Each path component may omit the unit address portion, but the
369 * results of this are undefined if any such path component is
370 * ambiguous (that is if there are multiple nodes at the relevant
371 * level matching the given component, differentiated only by unit
375 * structure block offset of the node with the requested path (>=0), on
377 * -FDT_ERR_BADPATH, given path does not begin with '/' or is invalid
378 * -FDT_ERR_NOTFOUND, if the requested node does not exist
380 * -FDT_ERR_BADVERSION,
382 * -FDT_ERR_BADSTRUCTURE,
383 * -FDT_ERR_TRUNCATED, standard meanings.
385 int fdt_path_offset(const void *fdt, const char *path);
388 * fdt_get_name - retrieve the name of a given node
389 * @fdt: pointer to the device tree blob
390 * @nodeoffset: structure block offset of the starting node
391 * @lenp: pointer to an integer variable (will be overwritten) or NULL
393 * fdt_get_name() retrieves the name (including unit address) of the
394 * device tree node at structure block offset nodeoffset. If lenp is
395 * non-NULL, the length of this name is also returned, in the integer
396 * pointed to by lenp.
399 * pointer to the node's name, on success
400 * If lenp is non-NULL, *lenp contains the length of that name
403 * if lenp is non-NULL *lenp contains an error code (<0):
404 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
407 * -FDT_ERR_BADVERSION,
408 * -FDT_ERR_BADSTATE, standard meanings
410 const char *fdt_get_name(const void *fdt, int nodeoffset, int *lenp);
413 * fdt_first_property_offset - find the offset of a node's first property
414 * @fdt: pointer to the device tree blob
415 * @nodeoffset: structure block offset of a node
417 * fdt_first_property_offset() finds the first property of the node at
418 * the given structure block offset.
421 * structure block offset of the property (>=0), on success
422 * -FDT_ERR_NOTFOUND, if the requested node has no properties
423 * -FDT_ERR_BADOFFSET, if nodeoffset did not point to an FDT_BEGIN_NODE tag
425 * -FDT_ERR_BADVERSION,
427 * -FDT_ERR_BADSTRUCTURE,
428 * -FDT_ERR_TRUNCATED, standard meanings.
430 int fdt_first_property_offset(const void *fdt, int nodeoffset);
433 * fdt_next_property_offset - step through a node's properties
434 * @fdt: pointer to the device tree blob
435 * @offset: structure block offset of a property
437 * fdt_next_property_offset() finds the property immediately after the
438 * one at the given structure block offset. This will be a property
439 * of the same node as the given property.
442 * structure block offset of the next property (>=0), on success
443 * -FDT_ERR_NOTFOUND, if the given property is the last in its node
444 * -FDT_ERR_BADOFFSET, if nodeoffset did not point to an FDT_PROP tag
446 * -FDT_ERR_BADVERSION,
448 * -FDT_ERR_BADSTRUCTURE,
449 * -FDT_ERR_TRUNCATED, standard meanings.
451 int fdt_next_property_offset(const void *fdt, int offset);
454 * fdt_for_each_property_offset - iterate over all properties of a node
456 * @property_offset: property offset (int, lvalue)
457 * @fdt: FDT blob (const void *)
458 * @node: node offset (int)
460 * This is actually a wrapper around a for loop and would be used like so:
462 * fdt_for_each_property_offset(property, fdt, node) {
467 * if ((property < 0) && (property != -FDT_ERR_NOT_FOUND)) {
471 * Note that this is implemented as a macro and property is used as
472 * iterator in the loop. The node variable can be constant or even a
475 #define fdt_for_each_property_offset(property, fdt, node) \
476 for (property = fdt_first_property_offset(fdt, node); \
478 property = fdt_next_property_offset(fdt, property))
481 * fdt_get_property_by_offset - retrieve the property at a given offset
482 * @fdt: pointer to the device tree blob
483 * @offset: offset of the property to retrieve
484 * @lenp: pointer to an integer variable (will be overwritten) or NULL
486 * fdt_get_property_by_offset() retrieves a pointer to the
487 * fdt_property structure within the device tree blob at the given
488 * offset. If lenp is non-NULL, the length of the property value is
489 * also returned, in the integer pointed to by lenp.
492 * pointer to the structure representing the property
493 * if lenp is non-NULL, *lenp contains the length of the property
496 * if lenp is non-NULL, *lenp contains an error code (<0):
497 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_PROP tag
499 * -FDT_ERR_BADVERSION,
501 * -FDT_ERR_BADSTRUCTURE,
502 * -FDT_ERR_TRUNCATED, standard meanings
504 const struct fdt_property *fdt_get_property_by_offset(const void *fdt,
509 * fdt_get_property_namelen - find a property based on substring
510 * @fdt: pointer to the device tree blob
511 * @nodeoffset: offset of the node whose property to find
512 * @name: name of the property to find
513 * @namelen: number of characters of name to consider
514 * @lenp: pointer to an integer variable (will be overwritten) or NULL
516 * Identical to fdt_get_property(), but only examine the first namelen
517 * characters of name for matching the property name.
519 #ifndef SWIG /* Not available in Python */
520 const struct fdt_property *fdt_get_property_namelen(const void *fdt,
523 int namelen, int *lenp);
527 * fdt_get_property - find a given property in a given node
528 * @fdt: pointer to the device tree blob
529 * @nodeoffset: offset of the node whose property to find
530 * @name: name of the property to find
531 * @lenp: pointer to an integer variable (will be overwritten) or NULL
533 * fdt_get_property() retrieves a pointer to the fdt_property
534 * structure within the device tree blob corresponding to the property
535 * named 'name' of the node at offset nodeoffset. If lenp is
536 * non-NULL, the length of the property value is also returned, in the
537 * integer pointed to by lenp.
540 * pointer to the structure representing the property
541 * if lenp is non-NULL, *lenp contains the length of the property
544 * if lenp is non-NULL, *lenp contains an error code (<0):
545 * -FDT_ERR_NOTFOUND, node does not have named property
546 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
549 * -FDT_ERR_BADVERSION,
551 * -FDT_ERR_BADSTRUCTURE,
552 * -FDT_ERR_TRUNCATED, standard meanings
554 const struct fdt_property *fdt_get_property(const void *fdt, int nodeoffset,
555 const char *name, int *lenp);
556 static inline struct fdt_property *fdt_get_property_w(void *fdt, int nodeoffset,
560 return (struct fdt_property *)(uintptr_t)
561 fdt_get_property(fdt, nodeoffset, name, lenp);
565 * fdt_getprop_by_offset - retrieve the value of a property at a given offset
566 * @fdt: pointer to the device tree blob
567 * @ffset: offset of the property to read
568 * @namep: pointer to a string variable (will be overwritten) or NULL
569 * @lenp: pointer to an integer variable (will be overwritten) or NULL
571 * fdt_getprop_by_offset() retrieves a pointer to the value of the
572 * property at structure block offset 'offset' (this will be a pointer
573 * to within the device blob itself, not a copy of the value). If
574 * lenp is non-NULL, the length of the property value is also
575 * returned, in the integer pointed to by lenp. If namep is non-NULL,
576 * the property's namne will also be returned in the char * pointed to
577 * by namep (this will be a pointer to within the device tree's string
578 * block, not a new copy of the name).
581 * pointer to the property's value
582 * if lenp is non-NULL, *lenp contains the length of the property
584 * if namep is non-NULL *namep contiains a pointer to the property
587 * if lenp is non-NULL, *lenp contains an error code (<0):
588 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_PROP tag
590 * -FDT_ERR_BADVERSION,
592 * -FDT_ERR_BADSTRUCTURE,
593 * -FDT_ERR_TRUNCATED, standard meanings
595 #ifndef SWIG /* This function is not useful in Python */
596 const void *fdt_getprop_by_offset(const void *fdt, int offset,
597 const char **namep, int *lenp);
601 * fdt_getprop_namelen - get property value based on substring
602 * @fdt: pointer to the device tree blob
603 * @nodeoffset: offset of the node whose property to find
604 * @name: name of the property to find
605 * @namelen: number of characters of name to consider
606 * @lenp: pointer to an integer variable (will be overwritten) or NULL
608 * Identical to fdt_getprop(), but only examine the first namelen
609 * characters of name for matching the property name.
611 #ifndef SWIG /* Not available in Python */
612 const void *fdt_getprop_namelen(const void *fdt, int nodeoffset,
613 const char *name, int namelen, int *lenp);
614 static inline void *fdt_getprop_namelen_w(void *fdt, int nodeoffset,
615 const char *name, int namelen,
618 return (void *)(uintptr_t)fdt_getprop_namelen(fdt, nodeoffset, name,
624 * fdt_getprop - retrieve the value of a given property
625 * @fdt: pointer to the device tree blob
626 * @nodeoffset: offset of the node whose property to find
627 * @name: name of the property to find
628 * @lenp: pointer to an integer variable (will be overwritten) or NULL
630 * fdt_getprop() retrieves a pointer to the value of the property
631 * named 'name' of the node at offset nodeoffset (this will be a
632 * pointer to within the device blob itself, not a copy of the value).
633 * If lenp is non-NULL, the length of the property value is also
634 * returned, in the integer pointed to by lenp.
637 * pointer to the property's value
638 * if lenp is non-NULL, *lenp contains the length of the property
641 * if lenp is non-NULL, *lenp contains an error code (<0):
642 * -FDT_ERR_NOTFOUND, node does not have named property
643 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
646 * -FDT_ERR_BADVERSION,
648 * -FDT_ERR_BADSTRUCTURE,
649 * -FDT_ERR_TRUNCATED, standard meanings
651 const void *fdt_getprop(const void *fdt, int nodeoffset,
652 const char *name, int *lenp);
653 static inline void *fdt_getprop_w(void *fdt, int nodeoffset,
654 const char *name, int *lenp)
656 return (void *)(uintptr_t)fdt_getprop(fdt, nodeoffset, name, lenp);
660 * fdt_get_phandle - retrieve the phandle of a given node
661 * @fdt: pointer to the device tree blob
662 * @nodeoffset: structure block offset of the node
664 * fdt_get_phandle() retrieves the phandle of the device tree node at
665 * structure block offset nodeoffset.
668 * the phandle of the node at nodeoffset, on success (!= 0, != -1)
669 * 0, if the node has no phandle, or another error occurs
671 uint32_t fdt_get_phandle(const void *fdt, int nodeoffset);
674 * fdt_get_alias_namelen - get alias based on substring
675 * @fdt: pointer to the device tree blob
676 * @name: name of the alias th look up
677 * @namelen: number of characters of name to consider
679 * Identical to fdt_get_alias(), but only examine the first namelen
680 * characters of name for matching the alias name.
682 #ifndef SWIG /* Not available in Python */
683 const char *fdt_get_alias_namelen(const void *fdt,
684 const char *name, int namelen);
688 * fdt_get_alias - retrieve the path referenced by a given alias
689 * @fdt: pointer to the device tree blob
690 * @name: name of the alias th look up
692 * fdt_get_alias() retrieves the value of a given alias. That is, the
693 * value of the property named 'name' in the node /aliases.
696 * a pointer to the expansion of the alias named 'name', if it exists
697 * NULL, if the given alias or the /aliases node does not exist
699 const char *fdt_get_alias(const void *fdt, const char *name);
702 * fdt_get_path - determine the full path of a node
703 * @fdt: pointer to the device tree blob
704 * @nodeoffset: offset of the node whose path to find
705 * @buf: character buffer to contain the returned path (will be overwritten)
706 * @buflen: size of the character buffer at buf
708 * fdt_get_path() computes the full path of the node at offset
709 * nodeoffset, and records that path in the buffer at buf.
711 * NOTE: This function is expensive, as it must scan the device tree
712 * structure from the start to nodeoffset.
716 * buf contains the absolute path of the node at
717 * nodeoffset, as a NUL-terminated string.
718 * -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
719 * -FDT_ERR_NOSPACE, the path of the given node is longer than (bufsize-1)
720 * characters and will not fit in the given buffer.
722 * -FDT_ERR_BADVERSION,
724 * -FDT_ERR_BADSTRUCTURE, standard meanings
726 int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen);
729 * fdt_supernode_atdepth_offset - find a specific ancestor of a node
730 * @fdt: pointer to the device tree blob
731 * @nodeoffset: offset of the node whose parent to find
732 * @supernodedepth: depth of the ancestor to find
733 * @nodedepth: pointer to an integer variable (will be overwritten) or NULL
735 * fdt_supernode_atdepth_offset() finds an ancestor of the given node
736 * at a specific depth from the root (where the root itself has depth
737 * 0, its immediate subnodes depth 1 and so forth). So
738 * fdt_supernode_atdepth_offset(fdt, nodeoffset, 0, NULL);
739 * will always return 0, the offset of the root node. If the node at
740 * nodeoffset has depth D, then:
741 * fdt_supernode_atdepth_offset(fdt, nodeoffset, D, NULL);
742 * will return nodeoffset itself.
744 * NOTE: This function is expensive, as it must scan the device tree
745 * structure from the start to nodeoffset.
748 * structure block offset of the node at node offset's ancestor
749 * of depth supernodedepth (>=0), on success
750 * -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
751 * -FDT_ERR_NOTFOUND, supernodedepth was greater than the depth of
754 * -FDT_ERR_BADVERSION,
756 * -FDT_ERR_BADSTRUCTURE, standard meanings
758 int fdt_supernode_atdepth_offset(const void *fdt, int nodeoffset,
759 int supernodedepth, int *nodedepth);
762 * fdt_node_depth - find the depth of a given node
763 * @fdt: pointer to the device tree blob
764 * @nodeoffset: offset of the node whose parent to find
766 * fdt_node_depth() finds the depth of a given node. The root node
767 * has depth 0, its immediate subnodes depth 1 and so forth.
769 * NOTE: This function is expensive, as it must scan the device tree
770 * structure from the start to nodeoffset.
773 * depth of the node at nodeoffset (>=0), on success
774 * -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
776 * -FDT_ERR_BADVERSION,
778 * -FDT_ERR_BADSTRUCTURE, standard meanings
780 int fdt_node_depth(const void *fdt, int nodeoffset);
783 * fdt_parent_offset - find the parent of a given node
784 * @fdt: pointer to the device tree blob
785 * @nodeoffset: offset of the node whose parent to find
787 * fdt_parent_offset() locates the parent node of a given node (that
788 * is, it finds the offset of the node which contains the node at
789 * nodeoffset as a subnode).
791 * NOTE: This function is expensive, as it must scan the device tree
792 * structure from the start to nodeoffset, *twice*.
795 * structure block offset of the parent of the node at nodeoffset
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_parent_offset(const void *fdt, int nodeoffset);
806 * fdt_node_offset_by_prop_value - find nodes with a given property value
807 * @fdt: pointer to the device tree blob
808 * @startoffset: only find nodes after this offset
809 * @propname: property name to check
810 * @propval: property value to search for
811 * @proplen: length of the value in propval
813 * fdt_node_offset_by_prop_value() returns the offset of the first
814 * node after startoffset, which has a property named propname whose
815 * value is of length proplen and has value equal to propval; or if
816 * startoffset is -1, the very first such node in the tree.
818 * To iterate through all nodes matching the criterion, the following
820 * offset = fdt_node_offset_by_prop_value(fdt, -1, propname,
822 * while (offset != -FDT_ERR_NOTFOUND) {
824 * offset = fdt_node_offset_by_prop_value(fdt, offset, propname,
828 * Note the -1 in the first call to the function, if 0 is used here
829 * instead, the function will never locate the root node, even if it
830 * matches the criterion.
833 * structure block offset of the located node (>= 0, >startoffset),
835 * -FDT_ERR_NOTFOUND, no node matching the criterion exists in the
836 * tree after startoffset
837 * -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
839 * -FDT_ERR_BADVERSION,
841 * -FDT_ERR_BADSTRUCTURE, standard meanings
843 int fdt_node_offset_by_prop_value(const void *fdt, int startoffset,
844 const char *propname,
845 const void *propval, int proplen);
848 * fdt_node_offset_by_phandle - find the node with a given phandle
849 * @fdt: pointer to the device tree blob
850 * @phandle: phandle value
852 * fdt_node_offset_by_phandle() returns the offset of the node
853 * which has the given phandle value. If there is more than one node
854 * in the tree with the given phandle (an invalid tree), results are
858 * structure block offset of the located node (>= 0), on success
859 * -FDT_ERR_NOTFOUND, no node with that phandle exists
860 * -FDT_ERR_BADPHANDLE, given phandle value was invalid (0 or -1)
862 * -FDT_ERR_BADVERSION,
864 * -FDT_ERR_BADSTRUCTURE, standard meanings
866 int fdt_node_offset_by_phandle(const void *fdt, uint32_t phandle);
869 * fdt_node_check_compatible: check a node's compatible property
870 * @fdt: pointer to the device tree blob
871 * @nodeoffset: offset of a tree node
872 * @compatible: string to match against
875 * fdt_node_check_compatible() returns 0 if the given node contains a
876 * 'compatible' property with the given string as one of its elements,
877 * it returns non-zero otherwise, or on error.
880 * 0, if the node has a 'compatible' property listing the given string
881 * 1, if the node has a 'compatible' property, but it does not list
883 * -FDT_ERR_NOTFOUND, if the given node has no 'compatible' property
884 * -FDT_ERR_BADOFFSET, if nodeoffset does not refer to a BEGIN_NODE tag
886 * -FDT_ERR_BADVERSION,
888 * -FDT_ERR_BADSTRUCTURE, standard meanings
890 int fdt_node_check_compatible(const void *fdt, int nodeoffset,
891 const char *compatible);
894 * fdt_node_offset_by_compatible - find nodes with a given 'compatible' value
895 * @fdt: pointer to the device tree blob
896 * @startoffset: only find nodes after this offset
897 * @compatible: 'compatible' string to match against
899 * fdt_node_offset_by_compatible() returns the offset of the first
900 * node after startoffset, which has a 'compatible' property which
901 * lists the given compatible string; or if startoffset is -1, the
902 * very first such node in the tree.
904 * To iterate through all nodes matching the criterion, the following
906 * offset = fdt_node_offset_by_compatible(fdt, -1, compatible);
907 * while (offset != -FDT_ERR_NOTFOUND) {
909 * offset = fdt_node_offset_by_compatible(fdt, offset, compatible);
912 * Note the -1 in the first call to the function, if 0 is used here
913 * instead, the function will never locate the root node, even if it
914 * matches the criterion.
917 * structure block offset of the located node (>= 0, >startoffset),
919 * -FDT_ERR_NOTFOUND, no node matching the criterion exists in the
920 * tree after startoffset
921 * -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
923 * -FDT_ERR_BADVERSION,
925 * -FDT_ERR_BADSTRUCTURE, standard meanings
927 int fdt_node_offset_by_compatible(const void *fdt, int startoffset,
928 const char *compatible);
931 * fdt_stringlist_contains - check a string list property for a string
932 * @strlist: Property containing a list of strings to check
933 * @listlen: Length of property
934 * @str: String to search for
936 * This is a utility function provided for convenience. The list contains
937 * one or more strings, each terminated by \0, as is found in a device tree
938 * "compatible" property.
940 * @return: 1 if the string is found in the list, 0 not found, or invalid list
942 int fdt_stringlist_contains(const char *strlist, int listlen, const char *str);
945 * fdt_stringlist_count - count the number of strings in a string list
946 * @fdt: pointer to the device tree blob
947 * @nodeoffset: offset of a tree node
948 * @property: name of the property containing the string list
950 * the number of strings in the given property
951 * -FDT_ERR_BADVALUE if the property value is not NUL-terminated
952 * -FDT_ERR_NOTFOUND if the property does not exist
954 int fdt_stringlist_count(const void *fdt, int nodeoffset, const char *property);
957 * fdt_stringlist_search - find a string in a string list and return its index
958 * @fdt: pointer to the device tree blob
959 * @nodeoffset: offset of a tree node
960 * @property: name of the property containing the string list
961 * @string: string to look up in the string list
963 * Note that it is possible for this function to succeed on property values
964 * that are not NUL-terminated. That's because the function will stop after
965 * finding the first occurrence of @string. This can for example happen with
966 * small-valued cell properties, such as #address-cells, when searching for
970 * the index of the string in the list of strings
971 * -FDT_ERR_BADVALUE if the property value is not NUL-terminated
972 * -FDT_ERR_NOTFOUND if the property does not exist or does not contain
975 int fdt_stringlist_search(const void *fdt, int nodeoffset, const char *property,
979 * fdt_stringlist_get() - obtain the string at a given index in a string list
980 * @fdt: pointer to the device tree blob
981 * @nodeoffset: offset of a tree node
982 * @property: name of the property containing the string list
983 * @index: index of the string to return
984 * @lenp: return location for the string length or an error code on failure
986 * Note that this will successfully extract strings from properties with
987 * non-NUL-terminated values. For example on small-valued cell properties
988 * this function will return the empty string.
990 * If non-NULL, the length of the string (on success) or a negative error-code
991 * (on failure) will be stored in the integer pointer to by lenp.
994 * A pointer to the string at the given index in the string list or NULL on
995 * failure. On success the length of the string will be stored in the memory
996 * location pointed to by the lenp parameter, if non-NULL. On failure one of
997 * the following negative error codes will be returned in the lenp parameter
999 * -FDT_ERR_BADVALUE if the property value is not NUL-terminated
1000 * -FDT_ERR_NOTFOUND if the property does not exist
1002 const char *fdt_stringlist_get(const void *fdt, int nodeoffset,
1003 const char *property, int index,
1006 /**********************************************************************/
1007 /* Read-only functions (addressing related) */
1008 /**********************************************************************/
1011 * FDT_MAX_NCELLS - maximum value for #address-cells and #size-cells
1013 * This is the maximum value for #address-cells, #size-cells and
1014 * similar properties that will be processed by libfdt. IEE1275
1015 * requires that OF implementations handle values up to 4.
1016 * Implementations may support larger values, but in practice higher
1017 * values aren't used.
1019 #define FDT_MAX_NCELLS 4
1022 * fdt_address_cells - retrieve address size for a bus represented in the tree
1023 * @fdt: pointer to the device tree blob
1024 * @nodeoffset: offset of the node to find the address size for
1026 * When the node has a valid #address-cells property, returns its value.
1029 * 0 <= n < FDT_MAX_NCELLS, on success
1030 * 2, if the node has no #address-cells property
1031 * -FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
1032 * #address-cells property
1033 * -FDT_ERR_BADMAGIC,
1034 * -FDT_ERR_BADVERSION,
1035 * -FDT_ERR_BADSTATE,
1036 * -FDT_ERR_BADSTRUCTURE,
1037 * -FDT_ERR_TRUNCATED, standard meanings
1039 int fdt_address_cells(const void *fdt, int nodeoffset);
1042 * fdt_size_cells - retrieve address range size for a bus represented in the
1044 * @fdt: pointer to the device tree blob
1045 * @nodeoffset: offset of the node to find the address range size for
1047 * When the node has a valid #size-cells property, returns its value.
1050 * 0 <= n < FDT_MAX_NCELLS, on success
1051 * 2, if the node has no #address-cells property
1052 * -FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
1053 * #size-cells property
1054 * -FDT_ERR_BADMAGIC,
1055 * -FDT_ERR_BADVERSION,
1056 * -FDT_ERR_BADSTATE,
1057 * -FDT_ERR_BADSTRUCTURE,
1058 * -FDT_ERR_TRUNCATED, standard meanings
1060 int fdt_size_cells(const void *fdt, int nodeoffset);
1063 /**********************************************************************/
1064 /* Write-in-place functions */
1065 /**********************************************************************/
1068 * fdt_setprop_inplace_namelen_partial - change a property's value,
1070 * @fdt: pointer to the device tree blob
1071 * @nodeoffset: offset of the node whose property to change
1072 * @name: name of the property to change
1073 * @namelen: number of characters of name to consider
1074 * @idx: index of the property to change in the array
1075 * @val: pointer to data to replace the property value with
1076 * @len: length of the property value
1078 * Identical to fdt_setprop_inplace(), but modifies the given property
1079 * starting from the given index, and using only the first characters
1080 * of the name. It is useful when you want to manipulate only one value of
1081 * an array and you have a string that doesn't end with \0.
1083 #ifndef SWIG /* Not available in Python */
1084 int fdt_setprop_inplace_namelen_partial(void *fdt, int nodeoffset,
1085 const char *name, int namelen,
1086 uint32_t idx, const void *val,
1091 * fdt_setprop_inplace - change a property's value, but not its size
1092 * @fdt: pointer to the device tree blob
1093 * @nodeoffset: offset of the node whose property to change
1094 * @name: name of the property to change
1095 * @val: pointer to data to replace the property value with
1096 * @len: length of the property value
1098 * fdt_setprop_inplace() replaces the value of a given property with
1099 * the data in val, of length len. This function cannot change the
1100 * size of a property, and so will only work if len is equal to the
1101 * current length of the property.
1103 * This function will alter only the bytes in the blob which contain
1104 * the given property value, and will not alter or move any other part
1109 * -FDT_ERR_NOSPACE, if len is not equal to the property's current length
1110 * -FDT_ERR_NOTFOUND, node does not have the named property
1111 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1112 * -FDT_ERR_BADMAGIC,
1113 * -FDT_ERR_BADVERSION,
1114 * -FDT_ERR_BADSTATE,
1115 * -FDT_ERR_BADSTRUCTURE,
1116 * -FDT_ERR_TRUNCATED, standard meanings
1118 #ifndef SWIG /* Not available in Python */
1119 int fdt_setprop_inplace(void *fdt, int nodeoffset, const char *name,
1120 const void *val, int len);
1124 * fdt_setprop_inplace_u32 - change the value of a 32-bit integer property
1125 * @fdt: pointer to the device tree blob
1126 * @nodeoffset: offset of the node whose property to change
1127 * @name: name of the property to change
1128 * @val: 32-bit integer value to replace the property with
1130 * fdt_setprop_inplace_u32() replaces the value of a given property
1131 * with the 32-bit integer value in val, converting val to big-endian
1132 * if necessary. This function cannot change the size of a property,
1133 * and so will only work if the property already exists and has length
1136 * This function will alter only the bytes in the blob which contain
1137 * the given property value, and will not alter or move any other part
1142 * -FDT_ERR_NOSPACE, if the property's length is not equal to 4
1143 * -FDT_ERR_NOTFOUND, node does not have the named property
1144 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1145 * -FDT_ERR_BADMAGIC,
1146 * -FDT_ERR_BADVERSION,
1147 * -FDT_ERR_BADSTATE,
1148 * -FDT_ERR_BADSTRUCTURE,
1149 * -FDT_ERR_TRUNCATED, standard meanings
1151 static inline int fdt_setprop_inplace_u32(void *fdt, int nodeoffset,
1152 const char *name, uint32_t val)
1154 fdt32_t tmp = cpu_to_fdt32(val);
1155 return fdt_setprop_inplace(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1159 * fdt_setprop_inplace_u64 - change the value of a 64-bit integer property
1160 * @fdt: pointer to the device tree blob
1161 * @nodeoffset: offset of the node whose property to change
1162 * @name: name of the property to change
1163 * @val: 64-bit integer value to replace the property with
1165 * fdt_setprop_inplace_u64() replaces the value of a given property
1166 * with the 64-bit integer value in val, converting val to big-endian
1167 * if necessary. This function cannot change the size of a property,
1168 * and so will only work if the property already exists and has length
1171 * This function will alter only the bytes in the blob which contain
1172 * the given property value, and will not alter or move any other part
1177 * -FDT_ERR_NOSPACE, if the property's length is not equal to 8
1178 * -FDT_ERR_NOTFOUND, node does not have the named property
1179 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1180 * -FDT_ERR_BADMAGIC,
1181 * -FDT_ERR_BADVERSION,
1182 * -FDT_ERR_BADSTATE,
1183 * -FDT_ERR_BADSTRUCTURE,
1184 * -FDT_ERR_TRUNCATED, standard meanings
1186 static inline int fdt_setprop_inplace_u64(void *fdt, int nodeoffset,
1187 const char *name, uint64_t val)
1189 fdt64_t tmp = cpu_to_fdt64(val);
1190 return fdt_setprop_inplace(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1194 * fdt_setprop_inplace_cell - change the value of a single-cell property
1196 * This is an alternative name for fdt_setprop_inplace_u32()
1198 static inline int fdt_setprop_inplace_cell(void *fdt, int nodeoffset,
1199 const char *name, uint32_t val)
1201 return fdt_setprop_inplace_u32(fdt, nodeoffset, name, val);
1205 * fdt_nop_property - replace a property with nop tags
1206 * @fdt: pointer to the device tree blob
1207 * @nodeoffset: offset of the node whose property to nop
1208 * @name: name of the property to nop
1210 * fdt_nop_property() will replace a given property's representation
1211 * in the blob with FDT_NOP tags, effectively removing it from the
1214 * This function will alter only the bytes in the blob which contain
1215 * the property, and will not alter or move any other part of the
1220 * -FDT_ERR_NOTFOUND, node does not have the named property
1221 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1222 * -FDT_ERR_BADMAGIC,
1223 * -FDT_ERR_BADVERSION,
1224 * -FDT_ERR_BADSTATE,
1225 * -FDT_ERR_BADSTRUCTURE,
1226 * -FDT_ERR_TRUNCATED, standard meanings
1228 int fdt_nop_property(void *fdt, int nodeoffset, const char *name);
1231 * fdt_nop_node - replace a node (subtree) with nop tags
1232 * @fdt: pointer to the device tree blob
1233 * @nodeoffset: offset of the node to nop
1235 * fdt_nop_node() will replace a given node's representation in the
1236 * blob, including all its subnodes, if any, with FDT_NOP tags,
1237 * effectively removing it from the tree.
1239 * This function will alter only the bytes in the blob which contain
1240 * the node and its properties and subnodes, and will not alter or
1241 * move any other part of the tree.
1245 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1246 * -FDT_ERR_BADMAGIC,
1247 * -FDT_ERR_BADVERSION,
1248 * -FDT_ERR_BADSTATE,
1249 * -FDT_ERR_BADSTRUCTURE,
1250 * -FDT_ERR_TRUNCATED, standard meanings
1252 int fdt_nop_node(void *fdt, int nodeoffset);
1254 /**********************************************************************/
1255 /* Sequential write functions */
1256 /**********************************************************************/
1258 int fdt_create(void *buf, int bufsize);
1259 int fdt_resize(void *fdt, void *buf, int bufsize);
1260 int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size);
1261 int fdt_finish_reservemap(void *fdt);
1262 int fdt_begin_node(void *fdt, const char *name);
1263 int fdt_property(void *fdt, const char *name, const void *val, int len);
1264 static inline int fdt_property_u32(void *fdt, const char *name, uint32_t val)
1266 fdt32_t tmp = cpu_to_fdt32(val);
1267 return fdt_property(fdt, name, &tmp, sizeof(tmp));
1269 static inline int fdt_property_u64(void *fdt, const char *name, uint64_t val)
1271 fdt64_t tmp = cpu_to_fdt64(val);
1272 return fdt_property(fdt, name, &tmp, sizeof(tmp));
1274 static inline int fdt_property_cell(void *fdt, const char *name, uint32_t val)
1276 return fdt_property_u32(fdt, name, val);
1280 * fdt_property_placeholder - add a new property and return a ptr to its value
1282 * @fdt: pointer to the device tree blob
1283 * @name: name of property to add
1284 * @len: length of property value in bytes
1285 * @valp: returns a pointer to where where the value should be placed
1289 * -FDT_ERR_BADMAGIC,
1290 * -FDT_ERR_NOSPACE, standard meanings
1292 int fdt_property_placeholder(void *fdt, const char *name, int len, void **valp);
1294 #define fdt_property_string(fdt, name, str) \
1295 fdt_property(fdt, name, str, strlen(str)+1)
1296 int fdt_end_node(void *fdt);
1297 int fdt_finish(void *fdt);
1299 /**********************************************************************/
1300 /* Read-write functions */
1301 /**********************************************************************/
1303 int fdt_create_empty_tree(void *buf, int bufsize);
1304 int fdt_open_into(const void *fdt, void *buf, int bufsize);
1305 int fdt_pack(void *fdt);
1308 * fdt_add_mem_rsv - add one memory reserve map entry
1309 * @fdt: pointer to the device tree blob
1310 * @address, @size: 64-bit values (native endian)
1312 * Adds a reserve map entry to the given blob reserving a region at
1313 * address address of length size.
1315 * This function will insert data into the reserve map and will
1316 * therefore change the indexes of some entries in the table.
1320 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1321 * contain the new reservation entry
1322 * -FDT_ERR_BADMAGIC,
1323 * -FDT_ERR_BADVERSION,
1324 * -FDT_ERR_BADSTATE,
1325 * -FDT_ERR_BADSTRUCTURE,
1326 * -FDT_ERR_BADLAYOUT,
1327 * -FDT_ERR_TRUNCATED, standard meanings
1329 int fdt_add_mem_rsv(void *fdt, uint64_t address, uint64_t size);
1332 * fdt_del_mem_rsv - remove a memory reserve map entry
1333 * @fdt: pointer to the device tree blob
1334 * @n: entry to remove
1336 * fdt_del_mem_rsv() removes the n-th memory reserve map entry from
1339 * This function will delete data from the reservation table and will
1340 * therefore change the indexes of some entries in the table.
1344 * -FDT_ERR_NOTFOUND, there is no entry of the given index (i.e. there
1345 * are less than n+1 reserve map entries)
1346 * -FDT_ERR_BADMAGIC,
1347 * -FDT_ERR_BADVERSION,
1348 * -FDT_ERR_BADSTATE,
1349 * -FDT_ERR_BADSTRUCTURE,
1350 * -FDT_ERR_BADLAYOUT,
1351 * -FDT_ERR_TRUNCATED, standard meanings
1353 int fdt_del_mem_rsv(void *fdt, int n);
1356 * fdt_set_name - change the name of a given node
1357 * @fdt: pointer to the device tree blob
1358 * @nodeoffset: structure block offset of a node
1359 * @name: name to give the node
1361 * fdt_set_name() replaces the name (including unit address, if any)
1362 * of the given node with the given string. NOTE: this function can't
1363 * efficiently check if the new name is unique amongst the given
1364 * node's siblings; results are undefined if this function is invoked
1365 * with a name equal to one of the given node's siblings.
1367 * This function may insert or delete data from the blob, and will
1368 * therefore change the offsets of some existing nodes.
1372 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob
1373 * to contain the new name
1374 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1375 * -FDT_ERR_BADMAGIC,
1376 * -FDT_ERR_BADVERSION,
1377 * -FDT_ERR_BADSTATE, standard meanings
1379 int fdt_set_name(void *fdt, int nodeoffset, const char *name);
1382 * fdt_setprop - create or change a property
1383 * @fdt: pointer to the device tree blob
1384 * @nodeoffset: offset of the node whose property to change
1385 * @name: name of the property to change
1386 * @val: pointer to data to set the property value to
1387 * @len: length of the property value
1389 * fdt_setprop() sets the value of the named property in the given
1390 * node to the given value and length, creating the property if it
1391 * does not already exist.
1393 * This function may insert or delete data from the blob, and will
1394 * therefore change the offsets of some existing nodes.
1398 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1399 * contain the new property value
1400 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1401 * -FDT_ERR_BADLAYOUT,
1402 * -FDT_ERR_BADMAGIC,
1403 * -FDT_ERR_BADVERSION,
1404 * -FDT_ERR_BADSTATE,
1405 * -FDT_ERR_BADSTRUCTURE,
1406 * -FDT_ERR_BADLAYOUT,
1407 * -FDT_ERR_TRUNCATED, standard meanings
1409 int fdt_setprop(void *fdt, int nodeoffset, const char *name,
1410 const void *val, int len);
1413 * fdt_setprop_u32 - set a property to a 32-bit integer
1414 * @fdt: pointer to the device tree blob
1415 * @nodeoffset: offset of the node whose property to change
1416 * @name: name of the property to change
1417 * @val: 32-bit integer value for the property (native endian)
1419 * fdt_setprop_u32() sets the value of the named property in the given
1420 * node to the given 32-bit integer value (converting to big-endian if
1421 * necessary), or creates a new property with that value if it does
1422 * not already exist.
1424 * This function may insert or delete data from the blob, and will
1425 * therefore change the offsets of some existing nodes.
1429 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1430 * contain the new property value
1431 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1432 * -FDT_ERR_BADLAYOUT,
1433 * -FDT_ERR_BADMAGIC,
1434 * -FDT_ERR_BADVERSION,
1435 * -FDT_ERR_BADSTATE,
1436 * -FDT_ERR_BADSTRUCTURE,
1437 * -FDT_ERR_BADLAYOUT,
1438 * -FDT_ERR_TRUNCATED, standard meanings
1440 static inline int fdt_setprop_u32(void *fdt, int nodeoffset, const char *name,
1443 fdt32_t tmp = cpu_to_fdt32(val);
1444 return fdt_setprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1448 * fdt_setprop_u64 - set a property to a 64-bit integer
1449 * @fdt: pointer to the device tree blob
1450 * @nodeoffset: offset of the node whose property to change
1451 * @name: name of the property to change
1452 * @val: 64-bit integer value for the property (native endian)
1454 * fdt_setprop_u64() sets the value of the named property in the given
1455 * node to the given 64-bit integer value (converting to big-endian if
1456 * necessary), or creates a new property with that value if it does
1457 * not already exist.
1459 * This function may insert or delete data from the blob, and will
1460 * therefore change the offsets of some existing nodes.
1464 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1465 * contain the new property value
1466 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1467 * -FDT_ERR_BADLAYOUT,
1468 * -FDT_ERR_BADMAGIC,
1469 * -FDT_ERR_BADVERSION,
1470 * -FDT_ERR_BADSTATE,
1471 * -FDT_ERR_BADSTRUCTURE,
1472 * -FDT_ERR_BADLAYOUT,
1473 * -FDT_ERR_TRUNCATED, standard meanings
1475 static inline int fdt_setprop_u64(void *fdt, int nodeoffset, const char *name,
1478 fdt64_t tmp = cpu_to_fdt64(val);
1479 return fdt_setprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1483 * fdt_setprop_cell - set a property to a single cell value
1485 * This is an alternative name for fdt_setprop_u32()
1487 static inline int fdt_setprop_cell(void *fdt, int nodeoffset, const char *name,
1490 return fdt_setprop_u32(fdt, nodeoffset, name, val);
1494 * fdt_setprop_string - set a property to a string value
1495 * @fdt: pointer to the device tree blob
1496 * @nodeoffset: offset of the node whose property to change
1497 * @name: name of the property to change
1498 * @str: string value for the property
1500 * fdt_setprop_string() sets the value of the named property in the
1501 * given node to the given string value (using the length of the
1502 * string to determine the new length of the property), or creates a
1503 * new property with that value if it does not already exist.
1505 * This function may insert or delete data from the blob, and will
1506 * therefore change the offsets of some existing nodes.
1510 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1511 * contain the new property value
1512 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1513 * -FDT_ERR_BADLAYOUT,
1514 * -FDT_ERR_BADMAGIC,
1515 * -FDT_ERR_BADVERSION,
1516 * -FDT_ERR_BADSTATE,
1517 * -FDT_ERR_BADSTRUCTURE,
1518 * -FDT_ERR_BADLAYOUT,
1519 * -FDT_ERR_TRUNCATED, standard meanings
1521 #define fdt_setprop_string(fdt, nodeoffset, name, str) \
1522 fdt_setprop((fdt), (nodeoffset), (name), (str), strlen(str)+1)
1526 * fdt_setprop_empty - set a property to an empty value
1527 * @fdt: pointer to the device tree blob
1528 * @nodeoffset: offset of the node whose property to change
1529 * @name: name of the property to change
1531 * fdt_setprop_empty() sets the value of the named property in the
1532 * given node to an empty (zero length) value, or creates a new empty
1533 * property if it does not already exist.
1535 * This function may insert or delete data from the blob, and will
1536 * therefore change the offsets of some existing nodes.
1540 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1541 * contain the new property value
1542 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1543 * -FDT_ERR_BADLAYOUT,
1544 * -FDT_ERR_BADMAGIC,
1545 * -FDT_ERR_BADVERSION,
1546 * -FDT_ERR_BADSTATE,
1547 * -FDT_ERR_BADSTRUCTURE,
1548 * -FDT_ERR_BADLAYOUT,
1549 * -FDT_ERR_TRUNCATED, standard meanings
1551 #define fdt_setprop_empty(fdt, nodeoffset, name) \
1552 fdt_setprop((fdt), (nodeoffset), (name), NULL, 0)
1555 * fdt_appendprop - append to or create a property
1556 * @fdt: pointer to the device tree blob
1557 * @nodeoffset: offset of the node whose property to change
1558 * @name: name of the property to append to
1559 * @val: pointer to data to append to the property value
1560 * @len: length of the data to append to the property value
1562 * fdt_appendprop() appends the value to the named property in the
1563 * given node, creating the property if it does not already exist.
1565 * This function may insert data into the blob, and will therefore
1566 * change the offsets of some existing nodes.
1570 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1571 * contain the new property value
1572 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1573 * -FDT_ERR_BADLAYOUT,
1574 * -FDT_ERR_BADMAGIC,
1575 * -FDT_ERR_BADVERSION,
1576 * -FDT_ERR_BADSTATE,
1577 * -FDT_ERR_BADSTRUCTURE,
1578 * -FDT_ERR_BADLAYOUT,
1579 * -FDT_ERR_TRUNCATED, standard meanings
1581 int fdt_appendprop(void *fdt, int nodeoffset, const char *name,
1582 const void *val, int len);
1585 * fdt_appendprop_u32 - append a 32-bit integer value to a property
1586 * @fdt: pointer to the device tree blob
1587 * @nodeoffset: offset of the node whose property to change
1588 * @name: name of the property to change
1589 * @val: 32-bit integer value to append to the property (native endian)
1591 * fdt_appendprop_u32() appends the given 32-bit integer value
1592 * (converting to big-endian if necessary) to the value of the named
1593 * property in the given node, or creates a new property with that
1594 * value if it does not already exist.
1596 * This function may insert data into the blob, and will therefore
1597 * change the offsets of some existing nodes.
1601 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1602 * contain the new property value
1603 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1604 * -FDT_ERR_BADLAYOUT,
1605 * -FDT_ERR_BADMAGIC,
1606 * -FDT_ERR_BADVERSION,
1607 * -FDT_ERR_BADSTATE,
1608 * -FDT_ERR_BADSTRUCTURE,
1609 * -FDT_ERR_BADLAYOUT,
1610 * -FDT_ERR_TRUNCATED, standard meanings
1612 static inline int fdt_appendprop_u32(void *fdt, int nodeoffset,
1613 const char *name, uint32_t val)
1615 fdt32_t tmp = cpu_to_fdt32(val);
1616 return fdt_appendprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1620 * fdt_appendprop_u64 - append a 64-bit integer value to a property
1621 * @fdt: pointer to the device tree blob
1622 * @nodeoffset: offset of the node whose property to change
1623 * @name: name of the property to change
1624 * @val: 64-bit integer value to append to the property (native endian)
1626 * fdt_appendprop_u64() appends the given 64-bit integer value
1627 * (converting to big-endian if necessary) to the value of the named
1628 * property in the given node, or creates a new property with that
1629 * value if it does not already exist.
1631 * This function may insert data into the blob, and will therefore
1632 * change the offsets of some existing nodes.
1636 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1637 * contain the new property value
1638 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1639 * -FDT_ERR_BADLAYOUT,
1640 * -FDT_ERR_BADMAGIC,
1641 * -FDT_ERR_BADVERSION,
1642 * -FDT_ERR_BADSTATE,
1643 * -FDT_ERR_BADSTRUCTURE,
1644 * -FDT_ERR_BADLAYOUT,
1645 * -FDT_ERR_TRUNCATED, standard meanings
1647 static inline int fdt_appendprop_u64(void *fdt, int nodeoffset,
1648 const char *name, uint64_t val)
1650 fdt64_t tmp = cpu_to_fdt64(val);
1651 return fdt_appendprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1655 * fdt_appendprop_cell - append a single cell value to a property
1657 * This is an alternative name for fdt_appendprop_u32()
1659 static inline int fdt_appendprop_cell(void *fdt, int nodeoffset,
1660 const char *name, uint32_t val)
1662 return fdt_appendprop_u32(fdt, nodeoffset, name, val);
1666 * fdt_appendprop_string - append a string to a property
1667 * @fdt: pointer to the device tree blob
1668 * @nodeoffset: offset of the node whose property to change
1669 * @name: name of the property to change
1670 * @str: string value to append to the property
1672 * fdt_appendprop_string() appends the given string to the value of
1673 * the named property in the given node, or creates a new property
1674 * with that value if it does not already exist.
1676 * This function may insert data into the blob, and will therefore
1677 * change the offsets of some existing nodes.
1681 * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1682 * contain the new property value
1683 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1684 * -FDT_ERR_BADLAYOUT,
1685 * -FDT_ERR_BADMAGIC,
1686 * -FDT_ERR_BADVERSION,
1687 * -FDT_ERR_BADSTATE,
1688 * -FDT_ERR_BADSTRUCTURE,
1689 * -FDT_ERR_BADLAYOUT,
1690 * -FDT_ERR_TRUNCATED, standard meanings
1692 #define fdt_appendprop_string(fdt, nodeoffset, name, str) \
1693 fdt_appendprop((fdt), (nodeoffset), (name), (str), strlen(str)+1)
1696 * fdt_delprop - delete a property
1697 * @fdt: pointer to the device tree blob
1698 * @nodeoffset: offset of the node whose property to nop
1699 * @name: name of the property to nop
1701 * fdt_del_property() will delete the given property.
1703 * This function will delete data from the blob, and will therefore
1704 * change the offsets of some existing nodes.
1708 * -FDT_ERR_NOTFOUND, node does not have the named property
1709 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1710 * -FDT_ERR_BADLAYOUT,
1711 * -FDT_ERR_BADMAGIC,
1712 * -FDT_ERR_BADVERSION,
1713 * -FDT_ERR_BADSTATE,
1714 * -FDT_ERR_BADSTRUCTURE,
1715 * -FDT_ERR_TRUNCATED, standard meanings
1717 int fdt_delprop(void *fdt, int nodeoffset, const char *name);
1720 * fdt_add_subnode_namelen - creates a new node based on substring
1721 * @fdt: pointer to the device tree blob
1722 * @parentoffset: structure block offset of a node
1723 * @name: name of the subnode to locate
1724 * @namelen: number of characters of name to consider
1726 * Identical to fdt_add_subnode(), but use only the first namelen
1727 * characters of name as the name of the new node. This is useful for
1728 * creating subnodes based on a portion of a larger string, such as a
1731 #ifndef SWIG /* Not available in Python */
1732 int fdt_add_subnode_namelen(void *fdt, int parentoffset,
1733 const char *name, int namelen);
1737 * fdt_add_subnode - creates a new node
1738 * @fdt: pointer to the device tree blob
1739 * @parentoffset: structure block offset of a node
1740 * @name: name of the subnode to locate
1742 * fdt_add_subnode() creates a new node as a subnode of the node at
1743 * structure block offset parentoffset, with the given name (which
1744 * should include the unit address, if any).
1746 * This function will insert data into the blob, and will therefore
1747 * change the offsets of some existing nodes.
1750 * structure block offset of the created nodeequested subnode (>=0), on
1752 * -FDT_ERR_NOTFOUND, if the requested subnode does not exist
1753 * -FDT_ERR_BADOFFSET, if parentoffset did not point to an FDT_BEGIN_NODE
1755 * -FDT_ERR_EXISTS, if the node at parentoffset already has a subnode of
1757 * -FDT_ERR_NOSPACE, if there is insufficient free space in the
1758 * blob to contain the new node
1760 * -FDT_ERR_BADLAYOUT
1761 * -FDT_ERR_BADMAGIC,
1762 * -FDT_ERR_BADVERSION,
1763 * -FDT_ERR_BADSTATE,
1764 * -FDT_ERR_BADSTRUCTURE,
1765 * -FDT_ERR_TRUNCATED, standard meanings.
1767 int fdt_add_subnode(void *fdt, int parentoffset, const char *name);
1770 * fdt_del_node - delete a node (subtree)
1771 * @fdt: pointer to the device tree blob
1772 * @nodeoffset: offset of the node to nop
1774 * fdt_del_node() will remove the given node, including all its
1775 * subnodes if any, from the blob.
1777 * This function will delete data from the blob, and will therefore
1778 * change the offsets of some existing nodes.
1782 * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1783 * -FDT_ERR_BADLAYOUT,
1784 * -FDT_ERR_BADMAGIC,
1785 * -FDT_ERR_BADVERSION,
1786 * -FDT_ERR_BADSTATE,
1787 * -FDT_ERR_BADSTRUCTURE,
1788 * -FDT_ERR_TRUNCATED, standard meanings
1790 int fdt_del_node(void *fdt, int nodeoffset);
1793 * fdt_overlay_apply - Applies a DT overlay on a base DT
1794 * @fdt: pointer to the base device tree blob
1795 * @fdto: pointer to the device tree overlay blob
1797 * fdt_overlay_apply() will apply the given device tree overlay on the
1798 * given base device tree.
1800 * Expect the base device tree to be modified, even if the function
1805 * -FDT_ERR_NOSPACE, there's not enough space in the base device tree
1806 * -FDT_ERR_NOTFOUND, the overlay points to some inexistant nodes or
1807 * properties in the base DT
1808 * -FDT_ERR_BADPHANDLE,
1809 * -FDT_ERR_BADOVERLAY,
1810 * -FDT_ERR_NOPHANDLES,
1811 * -FDT_ERR_INTERNAL,
1812 * -FDT_ERR_BADLAYOUT,
1813 * -FDT_ERR_BADMAGIC,
1814 * -FDT_ERR_BADOFFSET,
1816 * -FDT_ERR_BADVERSION,
1817 * -FDT_ERR_BADSTRUCTURE,
1818 * -FDT_ERR_BADSTATE,
1819 * -FDT_ERR_TRUNCATED, standard meanings
1821 int fdt_overlay_apply(void *fdt, void *fdto);
1823 /**********************************************************************/
1824 /* Debugging / informational functions */
1825 /**********************************************************************/
1827 #ifndef SWIG /* Not available in Python */
1828 const char *fdt_strerror(int errval);
1831 * fdt_remove_unused_strings() - Remove any unused strings from an FDT
1833 * This creates a new device tree in @new with unused strings removed. The
1834 * called can then use fdt_pack() to minimise the space consumed.
1836 * @old: Old device tree blog
1837 * @new: Place to put new device tree blob, which must be as large as
1841 * -FDT_ERR_BADOFFSET, corrupt device tree
1842 * -FDT_ERR_NOSPACE, out of space, which should not happen unless there
1843 * is something very wrong with the device tree input
1845 int fdt_remove_unused_strings(const void *old, void *new);
1853 * Flags for fdt_find_regions()
1855 * Add a region for the string table (always the last region)
1857 #define FDT_REG_ADD_STRING_TAB (1 << 0)
1860 * Add all supernodes of a matching node/property, useful for creating a
1863 #define FDT_REG_SUPERNODES (1 << 1)
1865 /* Add the FDT_BEGIN_NODE tags of subnodes, including their names */
1866 #define FDT_REG_DIRECT_SUBNODES (1 << 2)
1868 /* Add all subnodes of a matching node */
1869 #define FDT_REG_ALL_SUBNODES (1 << 3)
1871 /* Add a region for the mem_rsvmap table (always the first region) */
1872 #define FDT_REG_ADD_MEM_RSVMAP (1 << 4)
1874 /* Indicates what an fdt part is (node, property, value) */
1875 #define FDT_IS_NODE (1 << 0)
1876 #define FDT_IS_PROP (1 << 1)
1877 #define FDT_IS_VALUE (1 << 2) /* not supported */
1878 #define FDT_IS_COMPAT (1 << 3) /* used internally */
1879 #define FDT_NODE_HAS_PROP (1 << 4) /* node contains prop */
1881 #define FDT_ANY_GLOBAL (FDT_IS_NODE | FDT_IS_PROP | FDT_IS_VALUE | \
1883 #define FDT_IS_ANY 0x1f /* all the above */
1885 /* We set a reasonable limit on the number of nested nodes */
1886 #define FDT_MAX_DEPTH 32
1888 /* Decribes what we want to include from the current tag */
1891 WANT_NODES_ONLY, /* No properties */
1892 WANT_NODES_AND_PROPS, /* Everything for one level */
1893 WANT_ALL_NODES_AND_PROPS /* Everything for all levels */
1896 /* Keeps track of the state at parent nodes */
1897 struct fdt_subnode_stack {
1898 int offset; /* Offset of node */
1899 enum want_t want; /* The 'want' value here */
1900 int included; /* 1 if we included this node, 0 if not */
1903 struct fdt_region_ptrs {
1904 int depth; /* Current tree depth */
1905 int done; /* What we have completed scanning */
1906 enum want_t want; /* What we are currently including */
1907 char *end; /* Pointer to end of full node path */
1908 int nextoffset; /* Next node offset to check */
1911 /* The state of our finding algortihm */
1912 struct fdt_region_state {
1913 struct fdt_subnode_stack stack[FDT_MAX_DEPTH]; /* node stack */
1914 struct fdt_region *region; /* Contains list of regions found */
1915 int count; /* Numnber of regions found */
1916 const void *fdt; /* FDT blob */
1917 int max_regions; /* Maximum regions to find */
1918 int can_merge; /* 1 if we can merge with previous region */
1919 int start; /* Start position of current region */
1920 struct fdt_region_ptrs ptrs; /* Pointers for what we are up to */
1924 * fdt_find_regions() - find regions in device tree
1926 * Given a list of nodes to include and properties to exclude, find
1927 * the regions of the device tree which describe those included parts.
1929 * The intent is to get a list of regions which will be invariant provided
1930 * those parts are invariant. For example, if you request a list of regions
1931 * for all nodes but exclude the property "data", then you will get the
1932 * same region contents regardless of any change to "data" properties.
1934 * This function can be used to produce a byte-stream to send to a hashing
1935 * function to verify that critical parts of the FDT have not changed.
1937 * Nodes which are given in 'inc' are included in the region list, as
1938 * are the names of the immediate subnodes nodes (but not the properties
1939 * or subnodes of those subnodes).
1941 * For eaxample "/" means to include the root node, all root properties
1942 * and the FDT_BEGIN_NODE and FDT_END_NODE of all subnodes of /. The latter
1943 * ensures that we capture the names of the subnodes. In a hashing situation
1944 * it prevents the root node from changing at all Any change to non-excluded
1945 * properties, names of subnodes or number of subnodes would be detected.
1947 * When used with FITs this provides the ability to hash and sign parts of
1948 * the FIT based on different configurations in the FIT. Then it is
1949 * impossible to change anything about that configuration (include images
1950 * attached to the configuration), but it may be possible to add new
1951 * configurations, new images or new signatures within the existing
1954 * Adding new properties to a device tree may result in the string table
1955 * being extended (if the new property names are different from those
1956 * already added). This function can optionally include a region for
1957 * the string table so that this can be part of the hash too.
1959 * The device tree header is not included in the list.
1961 * @fdt: Device tree to check
1962 * @inc: List of node paths to included
1963 * @inc_count: Number of node paths in list
1964 * @exc_prop: List of properties names to exclude
1965 * @exc_prop_count: Number of properties in exclude list
1966 * @region: Returns list of regions
1967 * @max_region: Maximum length of region list
1968 * @path: Pointer to a temporary string for the function to use for
1969 * building path names
1970 * @path_len: Length of path, must be large enough to hold the longest
1972 * @add_string_tab: 1 to add a region for the string table
1973 * @return number of regions in list. If this is >max_regions then the
1974 * region array was exhausted. You should increase max_regions and try
1977 int fdt_find_regions(const void *fdt, char * const inc[], int inc_count,
1978 char * const exc_prop[], int exc_prop_count,
1979 struct fdt_region region[], int max_regions,
1980 char *path, int path_len, int add_string_tab);
1983 * fdt_first_region() - find regions in device tree
1985 * Given a nodes and properties to include and properties to exclude, find
1986 * the regions of the device tree which describe those included parts.
1988 * The use for this function is twofold. Firstly it provides a convenient
1989 * way of performing a structure-aware grep of the tree. For example it is
1990 * possible to grep for a node and get all the properties associated with
1991 * that node. Trees can be subsetted easily, by specifying the nodes that
1992 * are required, and then writing out the regions returned by this function.
1993 * This is useful for small resource-constrained systems, such as boot
1994 * loaders, which want to use an FDT but do not need to know about all of
1997 * Secondly it makes it easy to hash parts of the tree and detect changes.
1998 * The intent is to get a list of regions which will be invariant provided
1999 * those parts are invariant. For example, if you request a list of regions
2000 * for all nodes but exclude the property "data", then you will get the
2001 * same region contents regardless of any change to "data" properties.
2003 * This function can be used to produce a byte-stream to send to a hashing
2004 * function to verify that critical parts of the FDT have not changed.
2005 * Note that semantically null changes in order could still cause false
2006 * hash misses. Such reordering might happen if the tree is regenerated
2007 * from source, and nodes are reordered (the bytes-stream will be emitted
2008 * in a different order and mnay hash functions will detect this). However
2009 * if an existing tree is modified using libfdt functions, such as
2010 * fdt_add_subnode() and fdt_setprop(), then this problem is avoided.
2012 * The nodes/properties to include/exclude are defined by a function
2013 * provided by the caller. This function is called for each node and
2014 * property, and must return:
2016 * 0 - to exclude this part
2017 * 1 - to include this part
2018 * -1 - for FDT_IS_PROP only: no information is available, so include
2019 * if its containing node is included
2021 * The last case is only used to deal with properties. Often a property is
2022 * included if its containing node is included - this is the case where
2023 * -1 is returned.. However if the property is specifically required to be
2024 * included/excluded, then 0 or 1 can be returned. Note that including a
2025 * property when the FDT_REG_SUPERNODES flag is given will force its
2026 * containing node to be included since it is not valid to have a property
2027 * that is not in a node.
2029 * Using the information provided, the inclusion of a node can be controlled
2030 * either by a node name or its compatible string, or any other property
2031 * that the function can determine.
2033 * As an example, including node "/" means to include the root node and all
2034 * root properties. A flag provides a way of also including supernodes (of
2035 * which there is none for the root node), and another flag includes
2036 * immediate subnodes, so in this case we would get the FDT_BEGIN_NODE and
2037 * FDT_END_NODE of all subnodes of /.
2039 * The subnode feature helps in a hashing situation since it prevents the
2040 * root node from changing at all. Any change to non-excluded properties,
2041 * names of subnodes or number of subnodes would be detected.
2043 * When used with FITs this provides the ability to hash and sign parts of
2044 * the FIT based on different configurations in the FIT. Then it is
2045 * impossible to change anything about that configuration (include images
2046 * attached to the configuration), but it may be possible to add new
2047 * configurations, new images or new signatures within the existing
2050 * Adding new properties to a device tree may result in the string table
2051 * being extended (if the new property names are different from those
2052 * already added). This function can optionally include a region for
2053 * the string table so that this can be part of the hash too. This is always
2056 * The FDT also has a mem_rsvmap table which can also be included, and is
2057 * always the first region if so.
2059 * The device tree header is not included in the region list. Since the
2060 * contents of the FDT are changing (shrinking, often), the caller will need
2061 * to regenerate the header anyway.
2063 * @fdt: Device tree to check
2064 * @h_include: Function to call to determine whether to include a part or
2067 * @priv: Private pointer as passed to fdt_find_regions()
2068 * @fdt: Pointer to FDT blob
2069 * @offset: Offset of this node / property
2070 * @type: Type of this part, FDT_IS_...
2071 * @data: Pointer to data (node name, property name, compatible
2072 * string, value (not yet supported)
2073 * @size: Size of data, or 0 if none
2074 * @return 0 to exclude, 1 to include, -1 if no information is
2076 * @priv: Private pointer passed to h_include
2077 * @region: Returns list of regions, sorted by offset
2078 * @max_regions: Maximum length of region list
2079 * @path: Pointer to a temporary string for the function to use for
2080 * building path names
2081 * @path_len: Length of path, must be large enough to hold the longest
2083 * @flags: Various flags that control the region algortihm, see
2085 * @return number of regions in list. If this is >max_regions then the
2086 * region array was exhausted. You should increase max_regions and try
2087 * the call again. Only the first max_regions elements are available in the
2090 * On error a -ve value is return, which can be:
2092 * -FDT_ERR_BADSTRUCTURE (too deep or more END tags than BEGIN tags
2093 * -FDT_ERR_BADLAYOUT
2094 * -FDT_ERR_NOSPACE (path area is too small)
2096 int fdt_first_region(const void *fdt,
2097 int (*h_include)(void *priv, const void *fdt, int offset,
2098 int type, const char *data, int size),
2099 void *priv, struct fdt_region *region,
2100 char *path, int path_len, int flags,
2101 struct fdt_region_state *info);
2103 /** fdt_next_region() - find next region
2105 * See fdt_first_region() for full description. This function finds the
2106 * next region according to the provided parameters, which must be the same
2107 * as passed to fdt_first_region().
2109 * This function can additionally return -FDT_ERR_NOTFOUND when there are no
2112 int fdt_next_region(const void *fdt,
2113 int (*h_include)(void *priv, const void *fdt, int offset,
2114 int type, const char *data, int size),
2115 void *priv, struct fdt_region *region,
2116 char *path, int path_len, int flags,
2117 struct fdt_region_state *info);
2120 * fdt_add_alias_regions() - find aliases that point to existing regions
2122 * Once a device tree grep is complete some of the nodes will be present
2123 * and some will have been dropped. This function checks all the alias nodes
2124 * to figure out which points point to nodes which are still present. These
2125 * aliases need to be kept, along with the nodes they reference.
2127 * Given a list of regions function finds the aliases that still apply and
2128 * adds more regions to the list for these. This function is called after
2129 * fdt_next_region() has finished returning regions and requires the same
2132 * @fdt: Device tree file to reference
2133 * @region: List of regions that will be kept
2134 * @count: Number of regions
2135 * @max_regions: Number of entries that can fit in @region
2136 * @info: Region state as returned from fdt_next_region()
2137 * @return new number of regions in @region (i.e. count + the number added)
2138 * or -FDT_ERR_NOSPACE if there was not enough space.
2140 int fdt_add_alias_regions(const void *fdt, struct fdt_region *region, int count,
2141 int max_regions, struct fdt_region_state *info);
2144 #endif /* _LIBFDT_H */