xref: /linux/scripts/dtc/libfdt/libfdt.h (revision b7019ac550eb3916f34d79db583e9b7ea2524afa)
1 #ifndef LIBFDT_H
2 #define LIBFDT_H
3 /*
4  * libfdt - Flat Device Tree manipulation
5  * Copyright (C) 2006 David Gibson, IBM Corporation.
6  *
7  * libfdt is dual licensed: you can use it either under the terms of
8  * the GPL, or the BSD license, at your option.
9  *
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.
14  *
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.
19  *
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,
23  *     MA 02110-1301 USA
24  *
25  * Alternatively,
26  *
27  *  b) Redistribution and use in source and binary forms, with or
28  *     without modification, are permitted provided that the following
29  *     conditions are met:
30  *
31  *     1. Redistributions of source code must retain the above
32  *        copyright notice, this list of conditions and the following
33  *        disclaimer.
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.
38  *
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
42  *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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;
47  *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48  *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
49  *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
50  *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
51  *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
52  */
53 
54 #include "libfdt_env.h"
55 #include "fdt.h"
56 
57 #define FDT_FIRST_SUPPORTED_VERSION	0x02
58 #define FDT_LAST_SUPPORTED_VERSION	0x11
59 
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
65 	 * already exists */
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. */
71 
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
80 	 * absolute path) */
81 #define FDT_ERR_BADPHANDLE	6
82 	/* FDT_ERR_BADPHANDLE: Function was passed an invalid phandle.
83 	 * This can be caused either by an invalid phandle property
84 	 * length, or the phandle value was either 0 or -1, which are
85 	 * not permitted. */
86 #define FDT_ERR_BADSTATE	7
87 	/* FDT_ERR_BADSTATE: Function was passed an incomplete device
88 	 * tree created by the sequential-write functions, which is
89 	 * not sufficiently complete for the requested operation. */
90 
91 /* Error codes: codes for bad device tree blobs */
92 #define FDT_ERR_TRUNCATED	8
93 	/* FDT_ERR_TRUNCATED: FDT or a sub-block is improperly
94 	 * terminated (overflows, goes outside allowed bounds, or
95 	 * isn't properly terminated).  */
96 #define FDT_ERR_BADMAGIC	9
97 	/* FDT_ERR_BADMAGIC: Given "device tree" appears not to be a
98 	 * device tree at all - it is missing the flattened device
99 	 * tree magic number. */
100 #define FDT_ERR_BADVERSION	10
101 	/* FDT_ERR_BADVERSION: Given device tree has a version which
102 	 * can't be handled by the requested operation.  For
103 	 * read-write functions, this may mean that fdt_open_into() is
104 	 * required to convert the tree to the expected version. */
105 #define FDT_ERR_BADSTRUCTURE	11
106 	/* FDT_ERR_BADSTRUCTURE: Given device tree has a corrupt
107 	 * structure block or other serious error (e.g. misnested
108 	 * nodes, or subnodes preceding properties). */
109 #define FDT_ERR_BADLAYOUT	12
110 	/* FDT_ERR_BADLAYOUT: For read-write functions, the given
111 	 * device tree has it's sub-blocks in an order that the
112 	 * function can't handle (memory reserve map, then structure,
113 	 * then strings).  Use fdt_open_into() to reorganize the tree
114 	 * into a form suitable for the read-write operations. */
115 
116 /* "Can't happen" error indicating a bug in libfdt */
117 #define FDT_ERR_INTERNAL	13
118 	/* FDT_ERR_INTERNAL: libfdt has failed an internal assertion.
119 	 * Should never be returned, if it is, it indicates a bug in
120 	 * libfdt itself. */
121 
122 /* Errors in device tree content */
123 #define FDT_ERR_BADNCELLS	14
124 	/* FDT_ERR_BADNCELLS: Device tree has a #address-cells, #size-cells
125 	 * or similar property with a bad format or value */
126 
127 #define FDT_ERR_BADVALUE	15
128 	/* FDT_ERR_BADVALUE: Device tree has a property with an unexpected
129 	 * value. For example: a property expected to contain a string list
130 	 * is not NUL-terminated within the length of its value. */
131 
132 #define FDT_ERR_BADOVERLAY	16
133 	/* FDT_ERR_BADOVERLAY: The device tree overlay, while
134 	 * correctly structured, cannot be applied due to some
135 	 * unexpected or missing value, property or node. */
136 
137 #define FDT_ERR_NOPHANDLES	17
138 	/* FDT_ERR_NOPHANDLES: The device tree doesn't have any
139 	 * phandle available anymore without causing an overflow */
140 
141 #define FDT_ERR_MAX		17
142 
143 /**********************************************************************/
144 /* Low-level functions (you probably don't need these)                */
145 /**********************************************************************/
146 
147 #ifndef SWIG /* This function is not useful in Python */
148 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int checklen);
149 #endif
150 static inline void *fdt_offset_ptr_w(void *fdt, int offset, int checklen)
151 {
152 	return (void *)(uintptr_t)fdt_offset_ptr(fdt, offset, checklen);
153 }
154 
155 uint32_t fdt_next_tag(const void *fdt, int offset, int *nextoffset);
156 
157 /*
158  * Alignment helpers:
159  *     These helpers access words from a device tree blob.  They're
160  *     built to work even with unaligned pointers on platforms (ike
161  *     ARM) that don't like unaligned loads and stores
162  */
163 
164 static inline uint32_t fdt32_ld(const fdt32_t *p)
165 {
166 	const uint8_t *bp = (const uint8_t *)p;
167 
168 	return ((uint32_t)bp[0] << 24)
169 		| ((uint32_t)bp[1] << 16)
170 		| ((uint32_t)bp[2] << 8)
171 		| bp[3];
172 }
173 
174 static inline uint64_t fdt64_ld(const fdt64_t *p)
175 {
176 	const uint8_t *bp = (const uint8_t *)p;
177 
178 	return ((uint64_t)bp[0] << 56)
179 		| ((uint64_t)bp[1] << 48)
180 		| ((uint64_t)bp[2] << 40)
181 		| ((uint64_t)bp[3] << 32)
182 		| ((uint64_t)bp[4] << 24)
183 		| ((uint64_t)bp[5] << 16)
184 		| ((uint64_t)bp[6] << 8)
185 		| bp[7];
186 }
187 
188 /**********************************************************************/
189 /* Traversal functions                                                */
190 /**********************************************************************/
191 
192 int fdt_next_node(const void *fdt, int offset, int *depth);
193 
194 /**
195  * fdt_first_subnode() - get offset of first direct subnode
196  *
197  * @fdt:	FDT blob
198  * @offset:	Offset of node to check
199  * @return offset of first subnode, or -FDT_ERR_NOTFOUND if there is none
200  */
201 int fdt_first_subnode(const void *fdt, int offset);
202 
203 /**
204  * fdt_next_subnode() - get offset of next direct subnode
205  *
206  * After first calling fdt_first_subnode(), call this function repeatedly to
207  * get direct subnodes of a parent node.
208  *
209  * @fdt:	FDT blob
210  * @offset:	Offset of previous subnode
211  * @return offset of next subnode, or -FDT_ERR_NOTFOUND if there are no more
212  * subnodes
213  */
214 int fdt_next_subnode(const void *fdt, int offset);
215 
216 /**
217  * fdt_for_each_subnode - iterate over all subnodes of a parent
218  *
219  * @node:	child node (int, lvalue)
220  * @fdt:	FDT blob (const void *)
221  * @parent:	parent node (int)
222  *
223  * This is actually a wrapper around a for loop and would be used like so:
224  *
225  *	fdt_for_each_subnode(node, fdt, parent) {
226  *		Use node
227  *		...
228  *	}
229  *
230  *	if ((node < 0) && (node != -FDT_ERR_NOT_FOUND)) {
231  *		Error handling
232  *	}
233  *
234  * Note that this is implemented as a macro and @node is used as
235  * iterator in the loop. The parent variable be constant or even a
236  * literal.
237  *
238  */
239 #define fdt_for_each_subnode(node, fdt, parent)		\
240 	for (node = fdt_first_subnode(fdt, parent);	\
241 	     node >= 0;					\
242 	     node = fdt_next_subnode(fdt, node))
243 
244 /**********************************************************************/
245 /* General functions                                                  */
246 /**********************************************************************/
247 #define fdt_get_header(fdt, field) \
248 	(fdt32_ld(&((const struct fdt_header *)(fdt))->field))
249 #define fdt_magic(fdt)			(fdt_get_header(fdt, magic))
250 #define fdt_totalsize(fdt)		(fdt_get_header(fdt, totalsize))
251 #define fdt_off_dt_struct(fdt)		(fdt_get_header(fdt, off_dt_struct))
252 #define fdt_off_dt_strings(fdt)		(fdt_get_header(fdt, off_dt_strings))
253 #define fdt_off_mem_rsvmap(fdt)		(fdt_get_header(fdt, off_mem_rsvmap))
254 #define fdt_version(fdt)		(fdt_get_header(fdt, version))
255 #define fdt_last_comp_version(fdt)	(fdt_get_header(fdt, last_comp_version))
256 #define fdt_boot_cpuid_phys(fdt)	(fdt_get_header(fdt, boot_cpuid_phys))
257 #define fdt_size_dt_strings(fdt)	(fdt_get_header(fdt, size_dt_strings))
258 #define fdt_size_dt_struct(fdt)		(fdt_get_header(fdt, size_dt_struct))
259 
260 #define fdt_set_hdr_(name) \
261 	static inline void fdt_set_##name(void *fdt, uint32_t val) \
262 	{ \
263 		struct fdt_header *fdth = (struct fdt_header *)fdt; \
264 		fdth->name = cpu_to_fdt32(val); \
265 	}
266 fdt_set_hdr_(magic);
267 fdt_set_hdr_(totalsize);
268 fdt_set_hdr_(off_dt_struct);
269 fdt_set_hdr_(off_dt_strings);
270 fdt_set_hdr_(off_mem_rsvmap);
271 fdt_set_hdr_(version);
272 fdt_set_hdr_(last_comp_version);
273 fdt_set_hdr_(boot_cpuid_phys);
274 fdt_set_hdr_(size_dt_strings);
275 fdt_set_hdr_(size_dt_struct);
276 #undef fdt_set_hdr_
277 
278 /**
279  * fdt_header_size - return the size of the tree's header
280  * @fdt: pointer to a flattened device tree
281  */
282 size_t fdt_header_size_(uint32_t version);
283 static inline size_t fdt_header_size(const void *fdt)
284 {
285 	return fdt_header_size_(fdt_version(fdt));
286 }
287 
288 /**
289  * fdt_check_header - sanity check a device tree header
290 
291  * @fdt: pointer to data which might be a flattened device tree
292  *
293  * fdt_check_header() checks that the given buffer contains what
294  * appears to be a flattened device tree, and that the header contains
295  * valid information (to the extent that can be determined from the
296  * header alone).
297  *
298  * returns:
299  *     0, if the buffer appears to contain a valid device tree
300  *     -FDT_ERR_BADMAGIC,
301  *     -FDT_ERR_BADVERSION,
302  *     -FDT_ERR_BADSTATE,
303  *     -FDT_ERR_TRUNCATED, standard meanings, as above
304  */
305 int fdt_check_header(const void *fdt);
306 
307 /**
308  * fdt_move - move a device tree around in memory
309  * @fdt: pointer to the device tree to move
310  * @buf: pointer to memory where the device is to be moved
311  * @bufsize: size of the memory space at buf
312  *
313  * fdt_move() relocates, if possible, the device tree blob located at
314  * fdt to the buffer at buf of size bufsize.  The buffer may overlap
315  * with the existing device tree blob at fdt.  Therefore,
316  *     fdt_move(fdt, fdt, fdt_totalsize(fdt))
317  * should always succeed.
318  *
319  * returns:
320  *     0, on success
321  *     -FDT_ERR_NOSPACE, bufsize is insufficient to contain the device tree
322  *     -FDT_ERR_BADMAGIC,
323  *     -FDT_ERR_BADVERSION,
324  *     -FDT_ERR_BADSTATE, standard meanings
325  */
326 int fdt_move(const void *fdt, void *buf, int bufsize);
327 
328 /**********************************************************************/
329 /* Read-only functions                                                */
330 /**********************************************************************/
331 
332 int fdt_check_full(const void *fdt, size_t bufsize);
333 
334 /**
335  * fdt_get_string - retrieve a string from the strings block of a device tree
336  * @fdt: pointer to the device tree blob
337  * @stroffset: offset of the string within the strings block (native endian)
338  * @lenp: optional pointer to return the string's length
339  *
340  * fdt_get_string() retrieves a pointer to a single string from the
341  * strings block of the device tree blob at fdt, and optionally also
342  * returns the string's length in *lenp.
343  *
344  * returns:
345  *     a pointer to the string, on success
346  *     NULL, if stroffset is out of bounds, or doesn't point to a valid string
347  */
348 const char *fdt_get_string(const void *fdt, int stroffset, int *lenp);
349 
350 /**
351  * fdt_string - retrieve a string from the strings block of a device tree
352  * @fdt: pointer to the device tree blob
353  * @stroffset: offset of the string within the strings block (native endian)
354  *
355  * fdt_string() retrieves a pointer to a single string from the
356  * strings block of the device tree blob at fdt.
357  *
358  * returns:
359  *     a pointer to the string, on success
360  *     NULL, if stroffset is out of bounds, or doesn't point to a valid string
361  */
362 const char *fdt_string(const void *fdt, int stroffset);
363 
364 /**
365  * fdt_get_max_phandle - retrieves the highest phandle in a tree
366  * @fdt: pointer to the device tree blob
367  *
368  * fdt_get_max_phandle retrieves the highest phandle in the given
369  * device tree. This will ignore badly formatted phandles, or phandles
370  * with a value of 0 or -1.
371  *
372  * returns:
373  *      the highest phandle on success
374  *      0, if no phandle was found in the device tree
375  *      -1, if an error occurred
376  */
377 uint32_t fdt_get_max_phandle(const void *fdt);
378 
379 /**
380  * fdt_num_mem_rsv - retrieve the number of memory reserve map entries
381  * @fdt: pointer to the device tree blob
382  *
383  * Returns the number of entries in the device tree blob's memory
384  * reservation map.  This does not include the terminating 0,0 entry
385  * or any other (0,0) entries reserved for expansion.
386  *
387  * returns:
388  *     the number of entries
389  */
390 int fdt_num_mem_rsv(const void *fdt);
391 
392 /**
393  * fdt_get_mem_rsv - retrieve one memory reserve map entry
394  * @fdt: pointer to the device tree blob
395  * @address, @size: pointers to 64-bit variables
396  *
397  * On success, *address and *size will contain the address and size of
398  * the n-th reserve map entry from the device tree blob, in
399  * native-endian format.
400  *
401  * returns:
402  *     0, on success
403  *     -FDT_ERR_BADMAGIC,
404  *     -FDT_ERR_BADVERSION,
405  *     -FDT_ERR_BADSTATE, standard meanings
406  */
407 int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size);
408 
409 /**
410  * fdt_subnode_offset_namelen - find a subnode based on substring
411  * @fdt: pointer to the device tree blob
412  * @parentoffset: structure block offset of a node
413  * @name: name of the subnode to locate
414  * @namelen: number of characters of name to consider
415  *
416  * Identical to fdt_subnode_offset(), but only examine the first
417  * namelen characters of name for matching the subnode name.  This is
418  * useful for finding subnodes based on a portion of a larger string,
419  * such as a full path.
420  */
421 #ifndef SWIG /* Not available in Python */
422 int fdt_subnode_offset_namelen(const void *fdt, int parentoffset,
423 			       const char *name, int namelen);
424 #endif
425 /**
426  * fdt_subnode_offset - find a subnode of a given node
427  * @fdt: pointer to the device tree blob
428  * @parentoffset: structure block offset of a node
429  * @name: name of the subnode to locate
430  *
431  * fdt_subnode_offset() finds a subnode of the node at structure block
432  * offset parentoffset with the given name.  name may include a unit
433  * address, in which case fdt_subnode_offset() will find the subnode
434  * with that unit address, or the unit address may be omitted, in
435  * which case fdt_subnode_offset() will find an arbitrary subnode
436  * whose name excluding unit address matches the given name.
437  *
438  * returns:
439  *	structure block offset of the requested subnode (>=0), on success
440  *	-FDT_ERR_NOTFOUND, if the requested subnode does not exist
441  *	-FDT_ERR_BADOFFSET, if parentoffset did not point to an FDT_BEGIN_NODE
442  *		tag
443  *	-FDT_ERR_BADMAGIC,
444  *	-FDT_ERR_BADVERSION,
445  *	-FDT_ERR_BADSTATE,
446  *	-FDT_ERR_BADSTRUCTURE,
447  *	-FDT_ERR_TRUNCATED, standard meanings.
448  */
449 int fdt_subnode_offset(const void *fdt, int parentoffset, const char *name);
450 
451 /**
452  * fdt_path_offset_namelen - find a tree node by its full path
453  * @fdt: pointer to the device tree blob
454  * @path: full path of the node to locate
455  * @namelen: number of characters of path to consider
456  *
457  * Identical to fdt_path_offset(), but only consider the first namelen
458  * characters of path as the path name.
459  */
460 #ifndef SWIG /* Not available in Python */
461 int fdt_path_offset_namelen(const void *fdt, const char *path, int namelen);
462 #endif
463 
464 /**
465  * fdt_path_offset - find a tree node by its full path
466  * @fdt: pointer to the device tree blob
467  * @path: full path of the node to locate
468  *
469  * fdt_path_offset() finds a node of a given path in the device tree.
470  * Each path component may omit the unit address portion, but the
471  * results of this are undefined if any such path component is
472  * ambiguous (that is if there are multiple nodes at the relevant
473  * level matching the given component, differentiated only by unit
474  * address).
475  *
476  * returns:
477  *	structure block offset of the node with the requested path (>=0), on
478  *		success
479  *	-FDT_ERR_BADPATH, given path does not begin with '/' or is invalid
480  *	-FDT_ERR_NOTFOUND, if the requested node does not exist
481  *      -FDT_ERR_BADMAGIC,
482  *	-FDT_ERR_BADVERSION,
483  *	-FDT_ERR_BADSTATE,
484  *	-FDT_ERR_BADSTRUCTURE,
485  *	-FDT_ERR_TRUNCATED, standard meanings.
486  */
487 int fdt_path_offset(const void *fdt, const char *path);
488 
489 /**
490  * fdt_get_name - retrieve the name of a given node
491  * @fdt: pointer to the device tree blob
492  * @nodeoffset: structure block offset of the starting node
493  * @lenp: pointer to an integer variable (will be overwritten) or NULL
494  *
495  * fdt_get_name() retrieves the name (including unit address) of the
496  * device tree node at structure block offset nodeoffset.  If lenp is
497  * non-NULL, the length of this name is also returned, in the integer
498  * pointed to by lenp.
499  *
500  * returns:
501  *	pointer to the node's name, on success
502  *		If lenp is non-NULL, *lenp contains the length of that name
503  *			(>=0)
504  *	NULL, on error
505  *		if lenp is non-NULL *lenp contains an error code (<0):
506  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
507  *			tag
508  *		-FDT_ERR_BADMAGIC,
509  *		-FDT_ERR_BADVERSION,
510  *		-FDT_ERR_BADSTATE, standard meanings
511  */
512 const char *fdt_get_name(const void *fdt, int nodeoffset, int *lenp);
513 
514 /**
515  * fdt_first_property_offset - find the offset of a node's first property
516  * @fdt: pointer to the device tree blob
517  * @nodeoffset: structure block offset of a node
518  *
519  * fdt_first_property_offset() finds the first property of the node at
520  * the given structure block offset.
521  *
522  * returns:
523  *	structure block offset of the property (>=0), on success
524  *	-FDT_ERR_NOTFOUND, if the requested node has no properties
525  *	-FDT_ERR_BADOFFSET, if nodeoffset did not point to an FDT_BEGIN_NODE tag
526  *      -FDT_ERR_BADMAGIC,
527  *	-FDT_ERR_BADVERSION,
528  *	-FDT_ERR_BADSTATE,
529  *	-FDT_ERR_BADSTRUCTURE,
530  *	-FDT_ERR_TRUNCATED, standard meanings.
531  */
532 int fdt_first_property_offset(const void *fdt, int nodeoffset);
533 
534 /**
535  * fdt_next_property_offset - step through a node's properties
536  * @fdt: pointer to the device tree blob
537  * @offset: structure block offset of a property
538  *
539  * fdt_next_property_offset() finds the property immediately after the
540  * one at the given structure block offset.  This will be a property
541  * of the same node as the given property.
542  *
543  * returns:
544  *	structure block offset of the next property (>=0), on success
545  *	-FDT_ERR_NOTFOUND, if the given property is the last in its node
546  *	-FDT_ERR_BADOFFSET, if nodeoffset did not point to an FDT_PROP tag
547  *      -FDT_ERR_BADMAGIC,
548  *	-FDT_ERR_BADVERSION,
549  *	-FDT_ERR_BADSTATE,
550  *	-FDT_ERR_BADSTRUCTURE,
551  *	-FDT_ERR_TRUNCATED, standard meanings.
552  */
553 int fdt_next_property_offset(const void *fdt, int offset);
554 
555 /**
556  * fdt_for_each_property_offset - iterate over all properties of a node
557  *
558  * @property_offset:	property offset (int, lvalue)
559  * @fdt:		FDT blob (const void *)
560  * @node:		node offset (int)
561  *
562  * This is actually a wrapper around a for loop and would be used like so:
563  *
564  *	fdt_for_each_property_offset(property, fdt, node) {
565  *		Use property
566  *		...
567  *	}
568  *
569  *	if ((property < 0) && (property != -FDT_ERR_NOT_FOUND)) {
570  *		Error handling
571  *	}
572  *
573  * Note that this is implemented as a macro and property is used as
574  * iterator in the loop. The node variable can be constant or even a
575  * literal.
576  */
577 #define fdt_for_each_property_offset(property, fdt, node)	\
578 	for (property = fdt_first_property_offset(fdt, node);	\
579 	     property >= 0;					\
580 	     property = fdt_next_property_offset(fdt, property))
581 
582 /**
583  * fdt_get_property_by_offset - retrieve the property at a given offset
584  * @fdt: pointer to the device tree blob
585  * @offset: offset of the property to retrieve
586  * @lenp: pointer to an integer variable (will be overwritten) or NULL
587  *
588  * fdt_get_property_by_offset() retrieves a pointer to the
589  * fdt_property structure within the device tree blob at the given
590  * offset.  If lenp is non-NULL, the length of the property value is
591  * also returned, in the integer pointed to by lenp.
592  *
593  * Note that this code only works on device tree versions >= 16. fdt_getprop()
594  * works on all versions.
595  *
596  * returns:
597  *	pointer to the structure representing the property
598  *		if lenp is non-NULL, *lenp contains the length of the property
599  *		value (>=0)
600  *	NULL, on error
601  *		if lenp is non-NULL, *lenp contains an error code (<0):
602  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_PROP tag
603  *		-FDT_ERR_BADMAGIC,
604  *		-FDT_ERR_BADVERSION,
605  *		-FDT_ERR_BADSTATE,
606  *		-FDT_ERR_BADSTRUCTURE,
607  *		-FDT_ERR_TRUNCATED, standard meanings
608  */
609 const struct fdt_property *fdt_get_property_by_offset(const void *fdt,
610 						      int offset,
611 						      int *lenp);
612 
613 /**
614  * fdt_get_property_namelen - find a property based on substring
615  * @fdt: pointer to the device tree blob
616  * @nodeoffset: offset of the node whose property to find
617  * @name: name of the property to find
618  * @namelen: number of characters of name to consider
619  * @lenp: pointer to an integer variable (will be overwritten) or NULL
620  *
621  * Identical to fdt_get_property(), but only examine the first namelen
622  * characters of name for matching the property name.
623  */
624 #ifndef SWIG /* Not available in Python */
625 const struct fdt_property *fdt_get_property_namelen(const void *fdt,
626 						    int nodeoffset,
627 						    const char *name,
628 						    int namelen, int *lenp);
629 #endif
630 
631 /**
632  * fdt_get_property - find a given property in a given node
633  * @fdt: pointer to the device tree blob
634  * @nodeoffset: offset of the node whose property to find
635  * @name: name of the property to find
636  * @lenp: pointer to an integer variable (will be overwritten) or NULL
637  *
638  * fdt_get_property() retrieves a pointer to the fdt_property
639  * structure within the device tree blob corresponding to the property
640  * named 'name' of the node at offset nodeoffset.  If lenp is
641  * non-NULL, the length of the property value is also returned, in the
642  * integer pointed to by lenp.
643  *
644  * returns:
645  *	pointer to the structure representing the property
646  *		if lenp is non-NULL, *lenp contains the length of the property
647  *		value (>=0)
648  *	NULL, on error
649  *		if lenp is non-NULL, *lenp contains an error code (<0):
650  *		-FDT_ERR_NOTFOUND, node does not have named property
651  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
652  *			tag
653  *		-FDT_ERR_BADMAGIC,
654  *		-FDT_ERR_BADVERSION,
655  *		-FDT_ERR_BADSTATE,
656  *		-FDT_ERR_BADSTRUCTURE,
657  *		-FDT_ERR_TRUNCATED, standard meanings
658  */
659 const struct fdt_property *fdt_get_property(const void *fdt, int nodeoffset,
660 					    const char *name, int *lenp);
661 static inline struct fdt_property *fdt_get_property_w(void *fdt, int nodeoffset,
662 						      const char *name,
663 						      int *lenp)
664 {
665 	return (struct fdt_property *)(uintptr_t)
666 		fdt_get_property(fdt, nodeoffset, name, lenp);
667 }
668 
669 /**
670  * fdt_getprop_by_offset - retrieve the value of a property at a given offset
671  * @fdt: pointer to the device tree blob
672  * @ffset: offset of the property to read
673  * @namep: pointer to a string variable (will be overwritten) or NULL
674  * @lenp: pointer to an integer variable (will be overwritten) or NULL
675  *
676  * fdt_getprop_by_offset() retrieves a pointer to the value of the
677  * property at structure block offset 'offset' (this will be a pointer
678  * to within the device blob itself, not a copy of the value).  If
679  * lenp is non-NULL, the length of the property value is also
680  * returned, in the integer pointed to by lenp.  If namep is non-NULL,
681  * the property's namne will also be returned in the char * pointed to
682  * by namep (this will be a pointer to within the device tree's string
683  * block, not a new copy of the name).
684  *
685  * returns:
686  *	pointer to the property's value
687  *		if lenp is non-NULL, *lenp contains the length of the property
688  *		value (>=0)
689  *		if namep is non-NULL *namep contiains a pointer to the property
690  *		name.
691  *	NULL, on error
692  *		if lenp is non-NULL, *lenp contains an error code (<0):
693  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_PROP tag
694  *		-FDT_ERR_BADMAGIC,
695  *		-FDT_ERR_BADVERSION,
696  *		-FDT_ERR_BADSTATE,
697  *		-FDT_ERR_BADSTRUCTURE,
698  *		-FDT_ERR_TRUNCATED, standard meanings
699  */
700 #ifndef SWIG /* This function is not useful in Python */
701 const void *fdt_getprop_by_offset(const void *fdt, int offset,
702 				  const char **namep, int *lenp);
703 #endif
704 
705 /**
706  * fdt_getprop_namelen - get property value based on substring
707  * @fdt: pointer to the device tree blob
708  * @nodeoffset: offset of the node whose property to find
709  * @name: name of the property to find
710  * @namelen: number of characters of name to consider
711  * @lenp: pointer to an integer variable (will be overwritten) or NULL
712  *
713  * Identical to fdt_getprop(), but only examine the first namelen
714  * characters of name for matching the property name.
715  */
716 #ifndef SWIG /* Not available in Python */
717 const void *fdt_getprop_namelen(const void *fdt, int nodeoffset,
718 				const char *name, int namelen, int *lenp);
719 static inline void *fdt_getprop_namelen_w(void *fdt, int nodeoffset,
720 					  const char *name, int namelen,
721 					  int *lenp)
722 {
723 	return (void *)(uintptr_t)fdt_getprop_namelen(fdt, nodeoffset, name,
724 						      namelen, lenp);
725 }
726 #endif
727 
728 /**
729  * fdt_getprop - retrieve the value of a given property
730  * @fdt: pointer to the device tree blob
731  * @nodeoffset: offset of the node whose property to find
732  * @name: name of the property to find
733  * @lenp: pointer to an integer variable (will be overwritten) or NULL
734  *
735  * fdt_getprop() retrieves a pointer to the value of the property
736  * named 'name' of the node at offset nodeoffset (this will be a
737  * pointer to within the device blob itself, not a copy of the value).
738  * If lenp is non-NULL, the length of the property value is also
739  * returned, in the integer pointed to by lenp.
740  *
741  * returns:
742  *	pointer to the property's value
743  *		if lenp is non-NULL, *lenp contains the length of the property
744  *		value (>=0)
745  *	NULL, on error
746  *		if lenp is non-NULL, *lenp contains an error code (<0):
747  *		-FDT_ERR_NOTFOUND, node does not have named property
748  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
749  *			tag
750  *		-FDT_ERR_BADMAGIC,
751  *		-FDT_ERR_BADVERSION,
752  *		-FDT_ERR_BADSTATE,
753  *		-FDT_ERR_BADSTRUCTURE,
754  *		-FDT_ERR_TRUNCATED, standard meanings
755  */
756 const void *fdt_getprop(const void *fdt, int nodeoffset,
757 			const char *name, int *lenp);
758 static inline void *fdt_getprop_w(void *fdt, int nodeoffset,
759 				  const char *name, int *lenp)
760 {
761 	return (void *)(uintptr_t)fdt_getprop(fdt, nodeoffset, name, lenp);
762 }
763 
764 /**
765  * fdt_get_phandle - retrieve the phandle of a given node
766  * @fdt: pointer to the device tree blob
767  * @nodeoffset: structure block offset of the node
768  *
769  * fdt_get_phandle() retrieves the phandle of the device tree node at
770  * structure block offset nodeoffset.
771  *
772  * returns:
773  *	the phandle of the node at nodeoffset, on success (!= 0, != -1)
774  *	0, if the node has no phandle, or another error occurs
775  */
776 uint32_t fdt_get_phandle(const void *fdt, int nodeoffset);
777 
778 /**
779  * fdt_get_alias_namelen - get alias based on substring
780  * @fdt: pointer to the device tree blob
781  * @name: name of the alias th look up
782  * @namelen: number of characters of name to consider
783  *
784  * Identical to fdt_get_alias(), but only examine the first namelen
785  * characters of name for matching the alias name.
786  */
787 #ifndef SWIG /* Not available in Python */
788 const char *fdt_get_alias_namelen(const void *fdt,
789 				  const char *name, int namelen);
790 #endif
791 
792 /**
793  * fdt_get_alias - retrieve the path referenced by a given alias
794  * @fdt: pointer to the device tree blob
795  * @name: name of the alias th look up
796  *
797  * fdt_get_alias() retrieves the value of a given alias.  That is, the
798  * value of the property named 'name' in the node /aliases.
799  *
800  * returns:
801  *	a pointer to the expansion of the alias named 'name', if it exists
802  *	NULL, if the given alias or the /aliases node does not exist
803  */
804 const char *fdt_get_alias(const void *fdt, const char *name);
805 
806 /**
807  * fdt_get_path - determine the full path of a node
808  * @fdt: pointer to the device tree blob
809  * @nodeoffset: offset of the node whose path to find
810  * @buf: character buffer to contain the returned path (will be overwritten)
811  * @buflen: size of the character buffer at buf
812  *
813  * fdt_get_path() computes the full path of the node at offset
814  * nodeoffset, and records that path in the buffer at buf.
815  *
816  * NOTE: This function is expensive, as it must scan the device tree
817  * structure from the start to nodeoffset.
818  *
819  * returns:
820  *	0, on success
821  *		buf contains the absolute path of the node at
822  *		nodeoffset, as a NUL-terminated string.
823  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
824  *	-FDT_ERR_NOSPACE, the path of the given node is longer than (bufsize-1)
825  *		characters and will not fit in the given buffer.
826  *	-FDT_ERR_BADMAGIC,
827  *	-FDT_ERR_BADVERSION,
828  *	-FDT_ERR_BADSTATE,
829  *	-FDT_ERR_BADSTRUCTURE, standard meanings
830  */
831 int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen);
832 
833 /**
834  * fdt_supernode_atdepth_offset - find a specific ancestor of a node
835  * @fdt: pointer to the device tree blob
836  * @nodeoffset: offset of the node whose parent to find
837  * @supernodedepth: depth of the ancestor to find
838  * @nodedepth: pointer to an integer variable (will be overwritten) or NULL
839  *
840  * fdt_supernode_atdepth_offset() finds an ancestor of the given node
841  * at a specific depth from the root (where the root itself has depth
842  * 0, its immediate subnodes depth 1 and so forth).  So
843  *	fdt_supernode_atdepth_offset(fdt, nodeoffset, 0, NULL);
844  * will always return 0, the offset of the root node.  If the node at
845  * nodeoffset has depth D, then:
846  *	fdt_supernode_atdepth_offset(fdt, nodeoffset, D, NULL);
847  * will return nodeoffset itself.
848  *
849  * NOTE: This function is expensive, as it must scan the device tree
850  * structure from the start to nodeoffset.
851  *
852  * returns:
853  *	structure block offset of the node at node offset's ancestor
854  *		of depth supernodedepth (>=0), on success
855  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
856  *	-FDT_ERR_NOTFOUND, supernodedepth was greater than the depth of
857  *		nodeoffset
858  *	-FDT_ERR_BADMAGIC,
859  *	-FDT_ERR_BADVERSION,
860  *	-FDT_ERR_BADSTATE,
861  *	-FDT_ERR_BADSTRUCTURE, standard meanings
862  */
863 int fdt_supernode_atdepth_offset(const void *fdt, int nodeoffset,
864 				 int supernodedepth, int *nodedepth);
865 
866 /**
867  * fdt_node_depth - find the depth of a given node
868  * @fdt: pointer to the device tree blob
869  * @nodeoffset: offset of the node whose parent to find
870  *
871  * fdt_node_depth() finds the depth of a given node.  The root node
872  * has depth 0, its immediate subnodes depth 1 and so forth.
873  *
874  * NOTE: This function is expensive, as it must scan the device tree
875  * structure from the start to nodeoffset.
876  *
877  * returns:
878  *	depth of the node at nodeoffset (>=0), on success
879  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
880  *	-FDT_ERR_BADMAGIC,
881  *	-FDT_ERR_BADVERSION,
882  *	-FDT_ERR_BADSTATE,
883  *	-FDT_ERR_BADSTRUCTURE, standard meanings
884  */
885 int fdt_node_depth(const void *fdt, int nodeoffset);
886 
887 /**
888  * fdt_parent_offset - find the parent of a given node
889  * @fdt: pointer to the device tree blob
890  * @nodeoffset: offset of the node whose parent to find
891  *
892  * fdt_parent_offset() locates the parent node of a given node (that
893  * is, it finds the offset of the node which contains the node at
894  * nodeoffset as a subnode).
895  *
896  * NOTE: This function is expensive, as it must scan the device tree
897  * structure from the start to nodeoffset, *twice*.
898  *
899  * returns:
900  *	structure block offset of the parent of the node at nodeoffset
901  *		(>=0), on success
902  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
903  *	-FDT_ERR_BADMAGIC,
904  *	-FDT_ERR_BADVERSION,
905  *	-FDT_ERR_BADSTATE,
906  *	-FDT_ERR_BADSTRUCTURE, standard meanings
907  */
908 int fdt_parent_offset(const void *fdt, int nodeoffset);
909 
910 /**
911  * fdt_node_offset_by_prop_value - find nodes with a given property value
912  * @fdt: pointer to the device tree blob
913  * @startoffset: only find nodes after this offset
914  * @propname: property name to check
915  * @propval: property value to search for
916  * @proplen: length of the value in propval
917  *
918  * fdt_node_offset_by_prop_value() returns the offset of the first
919  * node after startoffset, which has a property named propname whose
920  * value is of length proplen and has value equal to propval; or if
921  * startoffset is -1, the very first such node in the tree.
922  *
923  * To iterate through all nodes matching the criterion, the following
924  * idiom can be used:
925  *	offset = fdt_node_offset_by_prop_value(fdt, -1, propname,
926  *					       propval, proplen);
927  *	while (offset != -FDT_ERR_NOTFOUND) {
928  *		// other code here
929  *		offset = fdt_node_offset_by_prop_value(fdt, offset, propname,
930  *						       propval, proplen);
931  *	}
932  *
933  * Note the -1 in the first call to the function, if 0 is used here
934  * instead, the function will never locate the root node, even if it
935  * matches the criterion.
936  *
937  * returns:
938  *	structure block offset of the located node (>= 0, >startoffset),
939  *		 on success
940  *	-FDT_ERR_NOTFOUND, no node matching the criterion exists in the
941  *		tree after startoffset
942  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
943  *	-FDT_ERR_BADMAGIC,
944  *	-FDT_ERR_BADVERSION,
945  *	-FDT_ERR_BADSTATE,
946  *	-FDT_ERR_BADSTRUCTURE, standard meanings
947  */
948 int fdt_node_offset_by_prop_value(const void *fdt, int startoffset,
949 				  const char *propname,
950 				  const void *propval, int proplen);
951 
952 /**
953  * fdt_node_offset_by_phandle - find the node with a given phandle
954  * @fdt: pointer to the device tree blob
955  * @phandle: phandle value
956  *
957  * fdt_node_offset_by_phandle() returns the offset of the node
958  * which has the given phandle value.  If there is more than one node
959  * in the tree with the given phandle (an invalid tree), results are
960  * undefined.
961  *
962  * returns:
963  *	structure block offset of the located node (>= 0), on success
964  *	-FDT_ERR_NOTFOUND, no node with that phandle exists
965  *	-FDT_ERR_BADPHANDLE, given phandle value was invalid (0 or -1)
966  *	-FDT_ERR_BADMAGIC,
967  *	-FDT_ERR_BADVERSION,
968  *	-FDT_ERR_BADSTATE,
969  *	-FDT_ERR_BADSTRUCTURE, standard meanings
970  */
971 int fdt_node_offset_by_phandle(const void *fdt, uint32_t phandle);
972 
973 /**
974  * fdt_node_check_compatible: check a node's compatible property
975  * @fdt: pointer to the device tree blob
976  * @nodeoffset: offset of a tree node
977  * @compatible: string to match against
978  *
979  *
980  * fdt_node_check_compatible() returns 0 if the given node contains a
981  * 'compatible' property with the given string as one of its elements,
982  * it returns non-zero otherwise, or on error.
983  *
984  * returns:
985  *	0, if the node has a 'compatible' property listing the given string
986  *	1, if the node has a 'compatible' property, but it does not list
987  *		the given string
988  *	-FDT_ERR_NOTFOUND, if the given node has no 'compatible' property
989  *	-FDT_ERR_BADOFFSET, if nodeoffset does not refer to a BEGIN_NODE tag
990  *	-FDT_ERR_BADMAGIC,
991  *	-FDT_ERR_BADVERSION,
992  *	-FDT_ERR_BADSTATE,
993  *	-FDT_ERR_BADSTRUCTURE, standard meanings
994  */
995 int fdt_node_check_compatible(const void *fdt, int nodeoffset,
996 			      const char *compatible);
997 
998 /**
999  * fdt_node_offset_by_compatible - find nodes with a given 'compatible' value
1000  * @fdt: pointer to the device tree blob
1001  * @startoffset: only find nodes after this offset
1002  * @compatible: 'compatible' string to match against
1003  *
1004  * fdt_node_offset_by_compatible() returns the offset of the first
1005  * node after startoffset, which has a 'compatible' property which
1006  * lists the given compatible string; or if startoffset is -1, the
1007  * very first such node in the tree.
1008  *
1009  * To iterate through all nodes matching the criterion, the following
1010  * idiom can be used:
1011  *	offset = fdt_node_offset_by_compatible(fdt, -1, compatible);
1012  *	while (offset != -FDT_ERR_NOTFOUND) {
1013  *		// other code here
1014  *		offset = fdt_node_offset_by_compatible(fdt, offset, compatible);
1015  *	}
1016  *
1017  * Note the -1 in the first call to the function, if 0 is used here
1018  * instead, the function will never locate the root node, even if it
1019  * matches the criterion.
1020  *
1021  * returns:
1022  *	structure block offset of the located node (>= 0, >startoffset),
1023  *		 on success
1024  *	-FDT_ERR_NOTFOUND, no node matching the criterion exists in the
1025  *		tree after startoffset
1026  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
1027  *	-FDT_ERR_BADMAGIC,
1028  *	-FDT_ERR_BADVERSION,
1029  *	-FDT_ERR_BADSTATE,
1030  *	-FDT_ERR_BADSTRUCTURE, standard meanings
1031  */
1032 int fdt_node_offset_by_compatible(const void *fdt, int startoffset,
1033 				  const char *compatible);
1034 
1035 /**
1036  * fdt_stringlist_contains - check a string list property for a string
1037  * @strlist: Property containing a list of strings to check
1038  * @listlen: Length of property
1039  * @str: String to search for
1040  *
1041  * This is a utility function provided for convenience. The list contains
1042  * one or more strings, each terminated by \0, as is found in a device tree
1043  * "compatible" property.
1044  *
1045  * @return: 1 if the string is found in the list, 0 not found, or invalid list
1046  */
1047 int fdt_stringlist_contains(const char *strlist, int listlen, const char *str);
1048 
1049 /**
1050  * fdt_stringlist_count - count the number of strings in a string list
1051  * @fdt: pointer to the device tree blob
1052  * @nodeoffset: offset of a tree node
1053  * @property: name of the property containing the string list
1054  * @return:
1055  *   the number of strings in the given property
1056  *   -FDT_ERR_BADVALUE if the property value is not NUL-terminated
1057  *   -FDT_ERR_NOTFOUND if the property does not exist
1058  */
1059 int fdt_stringlist_count(const void *fdt, int nodeoffset, const char *property);
1060 
1061 /**
1062  * fdt_stringlist_search - find a string in a string list and return its index
1063  * @fdt: pointer to the device tree blob
1064  * @nodeoffset: offset of a tree node
1065  * @property: name of the property containing the string list
1066  * @string: string to look up in the string list
1067  *
1068  * Note that it is possible for this function to succeed on property values
1069  * that are not NUL-terminated. That's because the function will stop after
1070  * finding the first occurrence of @string. This can for example happen with
1071  * small-valued cell properties, such as #address-cells, when searching for
1072  * the empty string.
1073  *
1074  * @return:
1075  *   the index of the string in the list of strings
1076  *   -FDT_ERR_BADVALUE if the property value is not NUL-terminated
1077  *   -FDT_ERR_NOTFOUND if the property does not exist or does not contain
1078  *                     the given string
1079  */
1080 int fdt_stringlist_search(const void *fdt, int nodeoffset, const char *property,
1081 			  const char *string);
1082 
1083 /**
1084  * fdt_stringlist_get() - obtain the string at a given index in a string list
1085  * @fdt: pointer to the device tree blob
1086  * @nodeoffset: offset of a tree node
1087  * @property: name of the property containing the string list
1088  * @index: index of the string to return
1089  * @lenp: return location for the string length or an error code on failure
1090  *
1091  * Note that this will successfully extract strings from properties with
1092  * non-NUL-terminated values. For example on small-valued cell properties
1093  * this function will return the empty string.
1094  *
1095  * If non-NULL, the length of the string (on success) or a negative error-code
1096  * (on failure) will be stored in the integer pointer to by lenp.
1097  *
1098  * @return:
1099  *   A pointer to the string at the given index in the string list or NULL on
1100  *   failure. On success the length of the string will be stored in the memory
1101  *   location pointed to by the lenp parameter, if non-NULL. On failure one of
1102  *   the following negative error codes will be returned in the lenp parameter
1103  *   (if non-NULL):
1104  *     -FDT_ERR_BADVALUE if the property value is not NUL-terminated
1105  *     -FDT_ERR_NOTFOUND if the property does not exist
1106  */
1107 const char *fdt_stringlist_get(const void *fdt, int nodeoffset,
1108 			       const char *property, int index,
1109 			       int *lenp);
1110 
1111 /**********************************************************************/
1112 /* Read-only functions (addressing related)                           */
1113 /**********************************************************************/
1114 
1115 /**
1116  * FDT_MAX_NCELLS - maximum value for #address-cells and #size-cells
1117  *
1118  * This is the maximum value for #address-cells, #size-cells and
1119  * similar properties that will be processed by libfdt.  IEE1275
1120  * requires that OF implementations handle values up to 4.
1121  * Implementations may support larger values, but in practice higher
1122  * values aren't used.
1123  */
1124 #define FDT_MAX_NCELLS		4
1125 
1126 /**
1127  * fdt_address_cells - retrieve address size for a bus represented in the tree
1128  * @fdt: pointer to the device tree blob
1129  * @nodeoffset: offset of the node to find the address size for
1130  *
1131  * When the node has a valid #address-cells property, returns its value.
1132  *
1133  * returns:
1134  *	0 <= n < FDT_MAX_NCELLS, on success
1135  *      2, if the node has no #address-cells property
1136  *      -FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
1137  *		#address-cells property
1138  *	-FDT_ERR_BADMAGIC,
1139  *	-FDT_ERR_BADVERSION,
1140  *	-FDT_ERR_BADSTATE,
1141  *	-FDT_ERR_BADSTRUCTURE,
1142  *	-FDT_ERR_TRUNCATED, standard meanings
1143  */
1144 int fdt_address_cells(const void *fdt, int nodeoffset);
1145 
1146 /**
1147  * fdt_size_cells - retrieve address range size for a bus represented in the
1148  *                  tree
1149  * @fdt: pointer to the device tree blob
1150  * @nodeoffset: offset of the node to find the address range size for
1151  *
1152  * When the node has a valid #size-cells property, returns its value.
1153  *
1154  * returns:
1155  *	0 <= n < FDT_MAX_NCELLS, on success
1156  *      1, if the node has no #size-cells property
1157  *      -FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
1158  *		#size-cells property
1159  *	-FDT_ERR_BADMAGIC,
1160  *	-FDT_ERR_BADVERSION,
1161  *	-FDT_ERR_BADSTATE,
1162  *	-FDT_ERR_BADSTRUCTURE,
1163  *	-FDT_ERR_TRUNCATED, standard meanings
1164  */
1165 int fdt_size_cells(const void *fdt, int nodeoffset);
1166 
1167 
1168 /**********************************************************************/
1169 /* Write-in-place functions                                           */
1170 /**********************************************************************/
1171 
1172 /**
1173  * fdt_setprop_inplace_namelen_partial - change a property's value,
1174  *                                       but not its size
1175  * @fdt: pointer to the device tree blob
1176  * @nodeoffset: offset of the node whose property to change
1177  * @name: name of the property to change
1178  * @namelen: number of characters of name to consider
1179  * @idx: index of the property to change in the array
1180  * @val: pointer to data to replace the property value with
1181  * @len: length of the property value
1182  *
1183  * Identical to fdt_setprop_inplace(), but modifies the given property
1184  * starting from the given index, and using only the first characters
1185  * of the name. It is useful when you want to manipulate only one value of
1186  * an array and you have a string that doesn't end with \0.
1187  */
1188 #ifndef SWIG /* Not available in Python */
1189 int fdt_setprop_inplace_namelen_partial(void *fdt, int nodeoffset,
1190 					const char *name, int namelen,
1191 					uint32_t idx, const void *val,
1192 					int len);
1193 #endif
1194 
1195 /**
1196  * fdt_setprop_inplace - change a property's value, but not its size
1197  * @fdt: pointer to the device tree blob
1198  * @nodeoffset: offset of the node whose property to change
1199  * @name: name of the property to change
1200  * @val: pointer to data to replace the property value with
1201  * @len: length of the property value
1202  *
1203  * fdt_setprop_inplace() replaces the value of a given property with
1204  * the data in val, of length len.  This function cannot change the
1205  * size of a property, and so will only work if len is equal to the
1206  * current length of the property.
1207  *
1208  * This function will alter only the bytes in the blob which contain
1209  * the given property value, and will not alter or move any other part
1210  * of the tree.
1211  *
1212  * returns:
1213  *	0, on success
1214  *	-FDT_ERR_NOSPACE, if len is not equal to the property's current length
1215  *	-FDT_ERR_NOTFOUND, node does not have the named property
1216  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1217  *	-FDT_ERR_BADMAGIC,
1218  *	-FDT_ERR_BADVERSION,
1219  *	-FDT_ERR_BADSTATE,
1220  *	-FDT_ERR_BADSTRUCTURE,
1221  *	-FDT_ERR_TRUNCATED, standard meanings
1222  */
1223 #ifndef SWIG /* Not available in Python */
1224 int fdt_setprop_inplace(void *fdt, int nodeoffset, const char *name,
1225 			const void *val, int len);
1226 #endif
1227 
1228 /**
1229  * fdt_setprop_inplace_u32 - change the value of a 32-bit integer property
1230  * @fdt: pointer to the device tree blob
1231  * @nodeoffset: offset of the node whose property to change
1232  * @name: name of the property to change
1233  * @val: 32-bit integer value to replace the property with
1234  *
1235  * fdt_setprop_inplace_u32() replaces the value of a given property
1236  * with the 32-bit integer value in val, converting val to big-endian
1237  * if necessary.  This function cannot change the size of a property,
1238  * and so will only work if the property already exists and has length
1239  * 4.
1240  *
1241  * This function will alter only the bytes in the blob which contain
1242  * the given property value, and will not alter or move any other part
1243  * of the tree.
1244  *
1245  * returns:
1246  *	0, on success
1247  *	-FDT_ERR_NOSPACE, if the property's length is not equal to 4
1248  *	-FDT_ERR_NOTFOUND, node does not have the named property
1249  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1250  *	-FDT_ERR_BADMAGIC,
1251  *	-FDT_ERR_BADVERSION,
1252  *	-FDT_ERR_BADSTATE,
1253  *	-FDT_ERR_BADSTRUCTURE,
1254  *	-FDT_ERR_TRUNCATED, standard meanings
1255  */
1256 static inline int fdt_setprop_inplace_u32(void *fdt, int nodeoffset,
1257 					  const char *name, uint32_t val)
1258 {
1259 	fdt32_t tmp = cpu_to_fdt32(val);
1260 	return fdt_setprop_inplace(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1261 }
1262 
1263 /**
1264  * fdt_setprop_inplace_u64 - change the value of a 64-bit integer property
1265  * @fdt: pointer to the device tree blob
1266  * @nodeoffset: offset of the node whose property to change
1267  * @name: name of the property to change
1268  * @val: 64-bit integer value to replace the property with
1269  *
1270  * fdt_setprop_inplace_u64() replaces the value of a given property
1271  * with the 64-bit integer value in val, converting val to big-endian
1272  * if necessary.  This function cannot change the size of a property,
1273  * and so will only work if the property already exists and has length
1274  * 8.
1275  *
1276  * This function will alter only the bytes in the blob which contain
1277  * the given property value, and will not alter or move any other part
1278  * of the tree.
1279  *
1280  * returns:
1281  *	0, on success
1282  *	-FDT_ERR_NOSPACE, if the property's length is not equal to 8
1283  *	-FDT_ERR_NOTFOUND, node does not have the named property
1284  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1285  *	-FDT_ERR_BADMAGIC,
1286  *	-FDT_ERR_BADVERSION,
1287  *	-FDT_ERR_BADSTATE,
1288  *	-FDT_ERR_BADSTRUCTURE,
1289  *	-FDT_ERR_TRUNCATED, standard meanings
1290  */
1291 static inline int fdt_setprop_inplace_u64(void *fdt, int nodeoffset,
1292 					  const char *name, uint64_t val)
1293 {
1294 	fdt64_t tmp = cpu_to_fdt64(val);
1295 	return fdt_setprop_inplace(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1296 }
1297 
1298 /**
1299  * fdt_setprop_inplace_cell - change the value of a single-cell property
1300  *
1301  * This is an alternative name for fdt_setprop_inplace_u32()
1302  */
1303 static inline int fdt_setprop_inplace_cell(void *fdt, int nodeoffset,
1304 					   const char *name, uint32_t val)
1305 {
1306 	return fdt_setprop_inplace_u32(fdt, nodeoffset, name, val);
1307 }
1308 
1309 /**
1310  * fdt_nop_property - replace a property with nop tags
1311  * @fdt: pointer to the device tree blob
1312  * @nodeoffset: offset of the node whose property to nop
1313  * @name: name of the property to nop
1314  *
1315  * fdt_nop_property() will replace a given property's representation
1316  * in the blob with FDT_NOP tags, effectively removing it from the
1317  * tree.
1318  *
1319  * This function will alter only the bytes in the blob which contain
1320  * the property, and will not alter or move any other part of the
1321  * tree.
1322  *
1323  * returns:
1324  *	0, on success
1325  *	-FDT_ERR_NOTFOUND, node does not have the named property
1326  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1327  *	-FDT_ERR_BADMAGIC,
1328  *	-FDT_ERR_BADVERSION,
1329  *	-FDT_ERR_BADSTATE,
1330  *	-FDT_ERR_BADSTRUCTURE,
1331  *	-FDT_ERR_TRUNCATED, standard meanings
1332  */
1333 int fdt_nop_property(void *fdt, int nodeoffset, const char *name);
1334 
1335 /**
1336  * fdt_nop_node - replace a node (subtree) with nop tags
1337  * @fdt: pointer to the device tree blob
1338  * @nodeoffset: offset of the node to nop
1339  *
1340  * fdt_nop_node() will replace a given node's representation in the
1341  * blob, including all its subnodes, if any, with FDT_NOP tags,
1342  * effectively removing it from the tree.
1343  *
1344  * This function will alter only the bytes in the blob which contain
1345  * the node and its properties and subnodes, and will not alter or
1346  * move any other part of the tree.
1347  *
1348  * returns:
1349  *	0, on success
1350  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1351  *	-FDT_ERR_BADMAGIC,
1352  *	-FDT_ERR_BADVERSION,
1353  *	-FDT_ERR_BADSTATE,
1354  *	-FDT_ERR_BADSTRUCTURE,
1355  *	-FDT_ERR_TRUNCATED, standard meanings
1356  */
1357 int fdt_nop_node(void *fdt, int nodeoffset);
1358 
1359 /**********************************************************************/
1360 /* Sequential write functions                                         */
1361 /**********************************************************************/
1362 
1363 int fdt_create(void *buf, int bufsize);
1364 int fdt_resize(void *fdt, void *buf, int bufsize);
1365 int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size);
1366 int fdt_finish_reservemap(void *fdt);
1367 int fdt_begin_node(void *fdt, const char *name);
1368 int fdt_property(void *fdt, const char *name, const void *val, int len);
1369 static inline int fdt_property_u32(void *fdt, const char *name, uint32_t val)
1370 {
1371 	fdt32_t tmp = cpu_to_fdt32(val);
1372 	return fdt_property(fdt, name, &tmp, sizeof(tmp));
1373 }
1374 static inline int fdt_property_u64(void *fdt, const char *name, uint64_t val)
1375 {
1376 	fdt64_t tmp = cpu_to_fdt64(val);
1377 	return fdt_property(fdt, name, &tmp, sizeof(tmp));
1378 }
1379 
1380 #ifndef SWIG /* Not available in Python */
1381 static inline int fdt_property_cell(void *fdt, const char *name, uint32_t val)
1382 {
1383 	return fdt_property_u32(fdt, name, val);
1384 }
1385 #endif
1386 
1387 /**
1388  * fdt_property_placeholder - add a new property and return a ptr to its value
1389  *
1390  * @fdt: pointer to the device tree blob
1391  * @name: name of property to add
1392  * @len: length of property value in bytes
1393  * @valp: returns a pointer to where where the value should be placed
1394  *
1395  * returns:
1396  *	0, on success
1397  *	-FDT_ERR_BADMAGIC,
1398  *	-FDT_ERR_NOSPACE, standard meanings
1399  */
1400 int fdt_property_placeholder(void *fdt, const char *name, int len, void **valp);
1401 
1402 #define fdt_property_string(fdt, name, str) \
1403 	fdt_property(fdt, name, str, strlen(str)+1)
1404 int fdt_end_node(void *fdt);
1405 int fdt_finish(void *fdt);
1406 
1407 /**********************************************************************/
1408 /* Read-write functions                                               */
1409 /**********************************************************************/
1410 
1411 int fdt_create_empty_tree(void *buf, int bufsize);
1412 int fdt_open_into(const void *fdt, void *buf, int bufsize);
1413 int fdt_pack(void *fdt);
1414 
1415 /**
1416  * fdt_add_mem_rsv - add one memory reserve map entry
1417  * @fdt: pointer to the device tree blob
1418  * @address, @size: 64-bit values (native endian)
1419  *
1420  * Adds a reserve map entry to the given blob reserving a region at
1421  * address address of length size.
1422  *
1423  * This function will insert data into the reserve map and will
1424  * therefore change the indexes of some entries in the table.
1425  *
1426  * returns:
1427  *	0, on success
1428  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1429  *		contain the new reservation entry
1430  *	-FDT_ERR_BADMAGIC,
1431  *	-FDT_ERR_BADVERSION,
1432  *	-FDT_ERR_BADSTATE,
1433  *	-FDT_ERR_BADSTRUCTURE,
1434  *	-FDT_ERR_BADLAYOUT,
1435  *	-FDT_ERR_TRUNCATED, standard meanings
1436  */
1437 int fdt_add_mem_rsv(void *fdt, uint64_t address, uint64_t size);
1438 
1439 /**
1440  * fdt_del_mem_rsv - remove a memory reserve map entry
1441  * @fdt: pointer to the device tree blob
1442  * @n: entry to remove
1443  *
1444  * fdt_del_mem_rsv() removes the n-th memory reserve map entry from
1445  * the blob.
1446  *
1447  * This function will delete data from the reservation table and will
1448  * therefore change the indexes of some entries in the table.
1449  *
1450  * returns:
1451  *	0, on success
1452  *	-FDT_ERR_NOTFOUND, there is no entry of the given index (i.e. there
1453  *		are less than n+1 reserve map entries)
1454  *	-FDT_ERR_BADMAGIC,
1455  *	-FDT_ERR_BADVERSION,
1456  *	-FDT_ERR_BADSTATE,
1457  *	-FDT_ERR_BADSTRUCTURE,
1458  *	-FDT_ERR_BADLAYOUT,
1459  *	-FDT_ERR_TRUNCATED, standard meanings
1460  */
1461 int fdt_del_mem_rsv(void *fdt, int n);
1462 
1463 /**
1464  * fdt_set_name - change the name of a given node
1465  * @fdt: pointer to the device tree blob
1466  * @nodeoffset: structure block offset of a node
1467  * @name: name to give the node
1468  *
1469  * fdt_set_name() replaces the name (including unit address, if any)
1470  * of the given node with the given string.  NOTE: this function can't
1471  * efficiently check if the new name is unique amongst the given
1472  * node's siblings; results are undefined if this function is invoked
1473  * with a name equal to one of the given node's siblings.
1474  *
1475  * This function may insert or delete data from the blob, and will
1476  * therefore change the offsets of some existing nodes.
1477  *
1478  * returns:
1479  *	0, on success
1480  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob
1481  *		to contain the new name
1482  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1483  *	-FDT_ERR_BADMAGIC,
1484  *	-FDT_ERR_BADVERSION,
1485  *	-FDT_ERR_BADSTATE, standard meanings
1486  */
1487 int fdt_set_name(void *fdt, int nodeoffset, const char *name);
1488 
1489 /**
1490  * fdt_setprop - create or change a property
1491  * @fdt: pointer to the device tree blob
1492  * @nodeoffset: offset of the node whose property to change
1493  * @name: name of the property to change
1494  * @val: pointer to data to set the property value to
1495  * @len: length of the property value
1496  *
1497  * fdt_setprop() sets the value of the named property in the given
1498  * node to the given value and length, creating the property if it
1499  * does not already exist.
1500  *
1501  * This function may insert or delete data from the blob, and will
1502  * therefore change the offsets of some existing nodes.
1503  *
1504  * returns:
1505  *	0, on success
1506  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1507  *		contain the new property value
1508  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1509  *	-FDT_ERR_BADLAYOUT,
1510  *	-FDT_ERR_BADMAGIC,
1511  *	-FDT_ERR_BADVERSION,
1512  *	-FDT_ERR_BADSTATE,
1513  *	-FDT_ERR_BADSTRUCTURE,
1514  *	-FDT_ERR_BADLAYOUT,
1515  *	-FDT_ERR_TRUNCATED, standard meanings
1516  */
1517 int fdt_setprop(void *fdt, int nodeoffset, const char *name,
1518 		const void *val, int len);
1519 
1520 /**
1521  * fdt_setprop_placeholder - allocate space for a property
1522  * @fdt: pointer to the device tree blob
1523  * @nodeoffset: offset of the node whose property to change
1524  * @name: name of the property to change
1525  * @len: length of the property value
1526  * @prop_data: return pointer to property data
1527  *
1528  * fdt_setprop_placeholer() allocates the named property in the given node.
1529  * If the property exists it is resized. In either case a pointer to the
1530  * property data is returned.
1531  *
1532  * This function may insert or delete data from the blob, and will
1533  * therefore change the offsets of some existing nodes.
1534  *
1535  * returns:
1536  *	0, on success
1537  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1538  *		contain the new property value
1539  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1540  *	-FDT_ERR_BADLAYOUT,
1541  *	-FDT_ERR_BADMAGIC,
1542  *	-FDT_ERR_BADVERSION,
1543  *	-FDT_ERR_BADSTATE,
1544  *	-FDT_ERR_BADSTRUCTURE,
1545  *	-FDT_ERR_BADLAYOUT,
1546  *	-FDT_ERR_TRUNCATED, standard meanings
1547  */
1548 int fdt_setprop_placeholder(void *fdt, int nodeoffset, const char *name,
1549 			    int len, void **prop_data);
1550 
1551 /**
1552  * fdt_setprop_u32 - set a property to a 32-bit integer
1553  * @fdt: pointer to the device tree blob
1554  * @nodeoffset: offset of the node whose property to change
1555  * @name: name of the property to change
1556  * @val: 32-bit integer value for the property (native endian)
1557  *
1558  * fdt_setprop_u32() sets the value of the named property in the given
1559  * node to the given 32-bit integer value (converting to big-endian if
1560  * necessary), or creates a new property with that value if it does
1561  * not already exist.
1562  *
1563  * This function may insert or delete data from the blob, and will
1564  * therefore change the offsets of some existing nodes.
1565  *
1566  * returns:
1567  *	0, on success
1568  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1569  *		contain the new property value
1570  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1571  *	-FDT_ERR_BADLAYOUT,
1572  *	-FDT_ERR_BADMAGIC,
1573  *	-FDT_ERR_BADVERSION,
1574  *	-FDT_ERR_BADSTATE,
1575  *	-FDT_ERR_BADSTRUCTURE,
1576  *	-FDT_ERR_BADLAYOUT,
1577  *	-FDT_ERR_TRUNCATED, standard meanings
1578  */
1579 static inline int fdt_setprop_u32(void *fdt, int nodeoffset, const char *name,
1580 				  uint32_t val)
1581 {
1582 	fdt32_t tmp = cpu_to_fdt32(val);
1583 	return fdt_setprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1584 }
1585 
1586 /**
1587  * fdt_setprop_u64 - set a property to a 64-bit integer
1588  * @fdt: pointer to the device tree blob
1589  * @nodeoffset: offset of the node whose property to change
1590  * @name: name of the property to change
1591  * @val: 64-bit integer value for the property (native endian)
1592  *
1593  * fdt_setprop_u64() sets the value of the named property in the given
1594  * node to the given 64-bit integer value (converting to big-endian if
1595  * necessary), or creates a new property with that value if it does
1596  * not already exist.
1597  *
1598  * This function may insert or delete data from the blob, and will
1599  * therefore change the offsets of some existing nodes.
1600  *
1601  * returns:
1602  *	0, on success
1603  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1604  *		contain the new property value
1605  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1606  *	-FDT_ERR_BADLAYOUT,
1607  *	-FDT_ERR_BADMAGIC,
1608  *	-FDT_ERR_BADVERSION,
1609  *	-FDT_ERR_BADSTATE,
1610  *	-FDT_ERR_BADSTRUCTURE,
1611  *	-FDT_ERR_BADLAYOUT,
1612  *	-FDT_ERR_TRUNCATED, standard meanings
1613  */
1614 static inline int fdt_setprop_u64(void *fdt, int nodeoffset, const char *name,
1615 				  uint64_t val)
1616 {
1617 	fdt64_t tmp = cpu_to_fdt64(val);
1618 	return fdt_setprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1619 }
1620 
1621 /**
1622  * fdt_setprop_cell - set a property to a single cell value
1623  *
1624  * This is an alternative name for fdt_setprop_u32()
1625  */
1626 static inline int fdt_setprop_cell(void *fdt, int nodeoffset, const char *name,
1627 				   uint32_t val)
1628 {
1629 	return fdt_setprop_u32(fdt, nodeoffset, name, val);
1630 }
1631 
1632 /**
1633  * fdt_setprop_string - set a property to a string value
1634  * @fdt: pointer to the device tree blob
1635  * @nodeoffset: offset of the node whose property to change
1636  * @name: name of the property to change
1637  * @str: string value for the property
1638  *
1639  * fdt_setprop_string() sets the value of the named property in the
1640  * given node to the given string value (using the length of the
1641  * string to determine the new length of the property), or creates a
1642  * new property with that value if it does not already exist.
1643  *
1644  * This function may insert or delete data from the blob, and will
1645  * therefore change the offsets of some existing nodes.
1646  *
1647  * returns:
1648  *	0, on success
1649  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1650  *		contain the new property value
1651  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1652  *	-FDT_ERR_BADLAYOUT,
1653  *	-FDT_ERR_BADMAGIC,
1654  *	-FDT_ERR_BADVERSION,
1655  *	-FDT_ERR_BADSTATE,
1656  *	-FDT_ERR_BADSTRUCTURE,
1657  *	-FDT_ERR_BADLAYOUT,
1658  *	-FDT_ERR_TRUNCATED, standard meanings
1659  */
1660 #define fdt_setprop_string(fdt, nodeoffset, name, str) \
1661 	fdt_setprop((fdt), (nodeoffset), (name), (str), strlen(str)+1)
1662 
1663 
1664 /**
1665  * fdt_setprop_empty - set a property to an empty value
1666  * @fdt: pointer to the device tree blob
1667  * @nodeoffset: offset of the node whose property to change
1668  * @name: name of the property to change
1669  *
1670  * fdt_setprop_empty() sets the value of the named property in the
1671  * given node to an empty (zero length) value, or creates a new empty
1672  * property if it does not already exist.
1673  *
1674  * This function may insert or delete data from the blob, and will
1675  * therefore change the offsets of some existing nodes.
1676  *
1677  * returns:
1678  *	0, on success
1679  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1680  *		contain the new property value
1681  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1682  *	-FDT_ERR_BADLAYOUT,
1683  *	-FDT_ERR_BADMAGIC,
1684  *	-FDT_ERR_BADVERSION,
1685  *	-FDT_ERR_BADSTATE,
1686  *	-FDT_ERR_BADSTRUCTURE,
1687  *	-FDT_ERR_BADLAYOUT,
1688  *	-FDT_ERR_TRUNCATED, standard meanings
1689  */
1690 #define fdt_setprop_empty(fdt, nodeoffset, name) \
1691 	fdt_setprop((fdt), (nodeoffset), (name), NULL, 0)
1692 
1693 /**
1694  * fdt_appendprop - append to or create a property
1695  * @fdt: pointer to the device tree blob
1696  * @nodeoffset: offset of the node whose property to change
1697  * @name: name of the property to append to
1698  * @val: pointer to data to append to the property value
1699  * @len: length of the data to append to the property value
1700  *
1701  * fdt_appendprop() appends the value to the named property in the
1702  * given node, creating the property if it does not already exist.
1703  *
1704  * This function may insert data into the blob, and will therefore
1705  * change the offsets of some existing nodes.
1706  *
1707  * returns:
1708  *	0, on success
1709  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1710  *		contain the new property value
1711  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1712  *	-FDT_ERR_BADLAYOUT,
1713  *	-FDT_ERR_BADMAGIC,
1714  *	-FDT_ERR_BADVERSION,
1715  *	-FDT_ERR_BADSTATE,
1716  *	-FDT_ERR_BADSTRUCTURE,
1717  *	-FDT_ERR_BADLAYOUT,
1718  *	-FDT_ERR_TRUNCATED, standard meanings
1719  */
1720 int fdt_appendprop(void *fdt, int nodeoffset, const char *name,
1721 		   const void *val, int len);
1722 
1723 /**
1724  * fdt_appendprop_u32 - append a 32-bit integer value to a property
1725  * @fdt: pointer to the device tree blob
1726  * @nodeoffset: offset of the node whose property to change
1727  * @name: name of the property to change
1728  * @val: 32-bit integer value to append to the property (native endian)
1729  *
1730  * fdt_appendprop_u32() appends the given 32-bit integer value
1731  * (converting to big-endian if necessary) to the value of the named
1732  * property in the given node, or creates a new property with that
1733  * value if it does not already exist.
1734  *
1735  * This function may insert data into the blob, and will therefore
1736  * change the offsets of some existing nodes.
1737  *
1738  * returns:
1739  *	0, on success
1740  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1741  *		contain the new property value
1742  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1743  *	-FDT_ERR_BADLAYOUT,
1744  *	-FDT_ERR_BADMAGIC,
1745  *	-FDT_ERR_BADVERSION,
1746  *	-FDT_ERR_BADSTATE,
1747  *	-FDT_ERR_BADSTRUCTURE,
1748  *	-FDT_ERR_BADLAYOUT,
1749  *	-FDT_ERR_TRUNCATED, standard meanings
1750  */
1751 static inline int fdt_appendprop_u32(void *fdt, int nodeoffset,
1752 				     const char *name, uint32_t val)
1753 {
1754 	fdt32_t tmp = cpu_to_fdt32(val);
1755 	return fdt_appendprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1756 }
1757 
1758 /**
1759  * fdt_appendprop_u64 - append a 64-bit integer value to a property
1760  * @fdt: pointer to the device tree blob
1761  * @nodeoffset: offset of the node whose property to change
1762  * @name: name of the property to change
1763  * @val: 64-bit integer value to append to the property (native endian)
1764  *
1765  * fdt_appendprop_u64() appends the given 64-bit integer value
1766  * (converting to big-endian if necessary) to the value of the named
1767  * property in the given node, or creates a new property with that
1768  * value if it does not already exist.
1769  *
1770  * This function may insert data into the blob, and will therefore
1771  * change the offsets of some existing nodes.
1772  *
1773  * returns:
1774  *	0, on success
1775  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1776  *		contain the new property value
1777  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1778  *	-FDT_ERR_BADLAYOUT,
1779  *	-FDT_ERR_BADMAGIC,
1780  *	-FDT_ERR_BADVERSION,
1781  *	-FDT_ERR_BADSTATE,
1782  *	-FDT_ERR_BADSTRUCTURE,
1783  *	-FDT_ERR_BADLAYOUT,
1784  *	-FDT_ERR_TRUNCATED, standard meanings
1785  */
1786 static inline int fdt_appendprop_u64(void *fdt, int nodeoffset,
1787 				     const char *name, uint64_t val)
1788 {
1789 	fdt64_t tmp = cpu_to_fdt64(val);
1790 	return fdt_appendprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1791 }
1792 
1793 /**
1794  * fdt_appendprop_cell - append a single cell value to a property
1795  *
1796  * This is an alternative name for fdt_appendprop_u32()
1797  */
1798 static inline int fdt_appendprop_cell(void *fdt, int nodeoffset,
1799 				      const char *name, uint32_t val)
1800 {
1801 	return fdt_appendprop_u32(fdt, nodeoffset, name, val);
1802 }
1803 
1804 /**
1805  * fdt_appendprop_string - append a string to a property
1806  * @fdt: pointer to the device tree blob
1807  * @nodeoffset: offset of the node whose property to change
1808  * @name: name of the property to change
1809  * @str: string value to append to the property
1810  *
1811  * fdt_appendprop_string() appends the given string to the value of
1812  * the named property in the given node, or creates a new property
1813  * with that value if it does not already exist.
1814  *
1815  * This function may insert data into the blob, and will therefore
1816  * change the offsets of some existing nodes.
1817  *
1818  * returns:
1819  *	0, on success
1820  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1821  *		contain the new property value
1822  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1823  *	-FDT_ERR_BADLAYOUT,
1824  *	-FDT_ERR_BADMAGIC,
1825  *	-FDT_ERR_BADVERSION,
1826  *	-FDT_ERR_BADSTATE,
1827  *	-FDT_ERR_BADSTRUCTURE,
1828  *	-FDT_ERR_BADLAYOUT,
1829  *	-FDT_ERR_TRUNCATED, standard meanings
1830  */
1831 #define fdt_appendprop_string(fdt, nodeoffset, name, str) \
1832 	fdt_appendprop((fdt), (nodeoffset), (name), (str), strlen(str)+1)
1833 
1834 /**
1835  * fdt_delprop - delete a property
1836  * @fdt: pointer to the device tree blob
1837  * @nodeoffset: offset of the node whose property to nop
1838  * @name: name of the property to nop
1839  *
1840  * fdt_del_property() will delete the given property.
1841  *
1842  * This function will delete data from the blob, and will therefore
1843  * change the offsets of some existing nodes.
1844  *
1845  * returns:
1846  *	0, on success
1847  *	-FDT_ERR_NOTFOUND, node does not have the named property
1848  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1849  *	-FDT_ERR_BADLAYOUT,
1850  *	-FDT_ERR_BADMAGIC,
1851  *	-FDT_ERR_BADVERSION,
1852  *	-FDT_ERR_BADSTATE,
1853  *	-FDT_ERR_BADSTRUCTURE,
1854  *	-FDT_ERR_TRUNCATED, standard meanings
1855  */
1856 int fdt_delprop(void *fdt, int nodeoffset, const char *name);
1857 
1858 /**
1859  * fdt_add_subnode_namelen - creates a new node based on substring
1860  * @fdt: pointer to the device tree blob
1861  * @parentoffset: structure block offset of a node
1862  * @name: name of the subnode to locate
1863  * @namelen: number of characters of name to consider
1864  *
1865  * Identical to fdt_add_subnode(), but use only the first namelen
1866  * characters of name as the name of the new node.  This is useful for
1867  * creating subnodes based on a portion of a larger string, such as a
1868  * full path.
1869  */
1870 #ifndef SWIG /* Not available in Python */
1871 int fdt_add_subnode_namelen(void *fdt, int parentoffset,
1872 			    const char *name, int namelen);
1873 #endif
1874 
1875 /**
1876  * fdt_add_subnode - creates a new node
1877  * @fdt: pointer to the device tree blob
1878  * @parentoffset: structure block offset of a node
1879  * @name: name of the subnode to locate
1880  *
1881  * fdt_add_subnode() creates a new node as a subnode of the node at
1882  * structure block offset parentoffset, with the given name (which
1883  * should include the unit address, if any).
1884  *
1885  * This function will insert data into the blob, and will therefore
1886  * change the offsets of some existing nodes.
1887 
1888  * returns:
1889  *	structure block offset of the created nodeequested subnode (>=0), on
1890  *		success
1891  *	-FDT_ERR_NOTFOUND, if the requested subnode does not exist
1892  *	-FDT_ERR_BADOFFSET, if parentoffset did not point to an FDT_BEGIN_NODE
1893  *		tag
1894  *	-FDT_ERR_EXISTS, if the node at parentoffset already has a subnode of
1895  *		the given name
1896  *	-FDT_ERR_NOSPACE, if there is insufficient free space in the
1897  *		blob to contain the new node
1898  *	-FDT_ERR_NOSPACE
1899  *	-FDT_ERR_BADLAYOUT
1900  *      -FDT_ERR_BADMAGIC,
1901  *	-FDT_ERR_BADVERSION,
1902  *	-FDT_ERR_BADSTATE,
1903  *	-FDT_ERR_BADSTRUCTURE,
1904  *	-FDT_ERR_TRUNCATED, standard meanings.
1905  */
1906 int fdt_add_subnode(void *fdt, int parentoffset, const char *name);
1907 
1908 /**
1909  * fdt_del_node - delete a node (subtree)
1910  * @fdt: pointer to the device tree blob
1911  * @nodeoffset: offset of the node to nop
1912  *
1913  * fdt_del_node() will remove the given node, including all its
1914  * subnodes if any, from the blob.
1915  *
1916  * This function will delete data from the blob, and will therefore
1917  * change the offsets of some existing nodes.
1918  *
1919  * returns:
1920  *	0, on success
1921  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1922  *	-FDT_ERR_BADLAYOUT,
1923  *	-FDT_ERR_BADMAGIC,
1924  *	-FDT_ERR_BADVERSION,
1925  *	-FDT_ERR_BADSTATE,
1926  *	-FDT_ERR_BADSTRUCTURE,
1927  *	-FDT_ERR_TRUNCATED, standard meanings
1928  */
1929 int fdt_del_node(void *fdt, int nodeoffset);
1930 
1931 /**
1932  * fdt_overlay_apply - Applies a DT overlay on a base DT
1933  * @fdt: pointer to the base device tree blob
1934  * @fdto: pointer to the device tree overlay blob
1935  *
1936  * fdt_overlay_apply() will apply the given device tree overlay on the
1937  * given base device tree.
1938  *
1939  * Expect the base device tree to be modified, even if the function
1940  * returns an error.
1941  *
1942  * returns:
1943  *	0, on success
1944  *	-FDT_ERR_NOSPACE, there's not enough space in the base device tree
1945  *	-FDT_ERR_NOTFOUND, the overlay points to some inexistant nodes or
1946  *		properties in the base DT
1947  *	-FDT_ERR_BADPHANDLE,
1948  *	-FDT_ERR_BADOVERLAY,
1949  *	-FDT_ERR_NOPHANDLES,
1950  *	-FDT_ERR_INTERNAL,
1951  *	-FDT_ERR_BADLAYOUT,
1952  *	-FDT_ERR_BADMAGIC,
1953  *	-FDT_ERR_BADOFFSET,
1954  *	-FDT_ERR_BADPATH,
1955  *	-FDT_ERR_BADVERSION,
1956  *	-FDT_ERR_BADSTRUCTURE,
1957  *	-FDT_ERR_BADSTATE,
1958  *	-FDT_ERR_TRUNCATED, standard meanings
1959  */
1960 int fdt_overlay_apply(void *fdt, void *fdto);
1961 
1962 /**********************************************************************/
1963 /* Debugging / informational functions                                */
1964 /**********************************************************************/
1965 
1966 const char *fdt_strerror(int errval);
1967 
1968 #endif /* LIBFDT_H */
1969