xref: /openbmc/linux/scripts/dtc/libfdt/libfdt.h (revision 62975d27)
1 /* SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause) */
2 #ifndef LIBFDT_H
3 #define LIBFDT_H
4 /*
5  * libfdt - Flat Device Tree manipulation
6  * Copyright (C) 2006 David Gibson, IBM Corporation.
7  */
8 
9 #include "libfdt_env.h"
10 #include "fdt.h"
11 
12 #ifdef __cplusplus
13 extern "C" {
14 #endif
15 
16 #define FDT_FIRST_SUPPORTED_VERSION	0x02
17 #define FDT_LAST_SUPPORTED_VERSION	0x11
18 
19 /* Error codes: informative error codes */
20 #define FDT_ERR_NOTFOUND	1
21 	/* FDT_ERR_NOTFOUND: The requested node or property does not exist */
22 #define FDT_ERR_EXISTS		2
23 	/* FDT_ERR_EXISTS: Attempted to create a node or property which
24 	 * already exists */
25 #define FDT_ERR_NOSPACE		3
26 	/* FDT_ERR_NOSPACE: Operation needed to expand the device
27 	 * tree, but its buffer did not have sufficient space to
28 	 * contain the expanded tree. Use fdt_open_into() to move the
29 	 * device tree to a buffer with more space. */
30 
31 /* Error codes: codes for bad parameters */
32 #define FDT_ERR_BADOFFSET	4
33 	/* FDT_ERR_BADOFFSET: Function was passed a structure block
34 	 * offset which is out-of-bounds, or which points to an
35 	 * unsuitable part of the structure for the operation. */
36 #define FDT_ERR_BADPATH		5
37 	/* FDT_ERR_BADPATH: Function was passed a badly formatted path
38 	 * (e.g. missing a leading / for a function which requires an
39 	 * absolute path) */
40 #define FDT_ERR_BADPHANDLE	6
41 	/* FDT_ERR_BADPHANDLE: Function was passed an invalid phandle.
42 	 * This can be caused either by an invalid phandle property
43 	 * length, or the phandle value was either 0 or -1, which are
44 	 * not permitted. */
45 #define FDT_ERR_BADSTATE	7
46 	/* FDT_ERR_BADSTATE: Function was passed an incomplete device
47 	 * tree created by the sequential-write functions, which is
48 	 * not sufficiently complete for the requested operation. */
49 
50 /* Error codes: codes for bad device tree blobs */
51 #define FDT_ERR_TRUNCATED	8
52 	/* FDT_ERR_TRUNCATED: FDT or a sub-block is improperly
53 	 * terminated (overflows, goes outside allowed bounds, or
54 	 * isn't properly terminated).  */
55 #define FDT_ERR_BADMAGIC	9
56 	/* FDT_ERR_BADMAGIC: Given "device tree" appears not to be a
57 	 * device tree at all - it is missing the flattened device
58 	 * tree magic number. */
59 #define FDT_ERR_BADVERSION	10
60 	/* FDT_ERR_BADVERSION: Given device tree has a version which
61 	 * can't be handled by the requested operation.  For
62 	 * read-write functions, this may mean that fdt_open_into() is
63 	 * required to convert the tree to the expected version. */
64 #define FDT_ERR_BADSTRUCTURE	11
65 	/* FDT_ERR_BADSTRUCTURE: Given device tree has a corrupt
66 	 * structure block or other serious error (e.g. misnested
67 	 * nodes, or subnodes preceding properties). */
68 #define FDT_ERR_BADLAYOUT	12
69 	/* FDT_ERR_BADLAYOUT: For read-write functions, the given
70 	 * device tree has it's sub-blocks in an order that the
71 	 * function can't handle (memory reserve map, then structure,
72 	 * then strings).  Use fdt_open_into() to reorganize the tree
73 	 * into a form suitable for the read-write operations. */
74 
75 /* "Can't happen" error indicating a bug in libfdt */
76 #define FDT_ERR_INTERNAL	13
77 	/* FDT_ERR_INTERNAL: libfdt has failed an internal assertion.
78 	 * Should never be returned, if it is, it indicates a bug in
79 	 * libfdt itself. */
80 
81 /* Errors in device tree content */
82 #define FDT_ERR_BADNCELLS	14
83 	/* FDT_ERR_BADNCELLS: Device tree has a #address-cells, #size-cells
84 	 * or similar property with a bad format or value */
85 
86 #define FDT_ERR_BADVALUE	15
87 	/* FDT_ERR_BADVALUE: Device tree has a property with an unexpected
88 	 * value. For example: a property expected to contain a string list
89 	 * is not NUL-terminated within the length of its value. */
90 
91 #define FDT_ERR_BADOVERLAY	16
92 	/* FDT_ERR_BADOVERLAY: The device tree overlay, while
93 	 * correctly structured, cannot be applied due to some
94 	 * unexpected or missing value, property or node. */
95 
96 #define FDT_ERR_NOPHANDLES	17
97 	/* FDT_ERR_NOPHANDLES: The device tree doesn't have any
98 	 * phandle available anymore without causing an overflow */
99 
100 #define FDT_ERR_BADFLAGS	18
101 	/* FDT_ERR_BADFLAGS: The function was passed a flags field that
102 	 * contains invalid flags or an invalid combination of flags. */
103 
104 #define FDT_ERR_MAX		18
105 
106 /* constants */
107 #define FDT_MAX_PHANDLE 0xfffffffe
108 	/* Valid values for phandles range from 1 to 2^32-2. */
109 
110 /**********************************************************************/
111 /* Low-level functions (you probably don't need these)                */
112 /**********************************************************************/
113 
114 #ifndef SWIG /* This function is not useful in Python */
115 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int checklen);
116 #endif
117 static inline void *fdt_offset_ptr_w(void *fdt, int offset, int checklen)
118 {
119 	return (void *)(uintptr_t)fdt_offset_ptr(fdt, offset, checklen);
120 }
121 
122 uint32_t fdt_next_tag(const void *fdt, int offset, int *nextoffset);
123 
124 /*
125  * Alignment helpers:
126  *     These helpers access words from a device tree blob.  They're
127  *     built to work even with unaligned pointers on platforms (ike
128  *     ARM) that don't like unaligned loads and stores
129  */
130 
131 static inline uint32_t fdt32_ld(const fdt32_t *p)
132 {
133 	const uint8_t *bp = (const uint8_t *)p;
134 
135 	return ((uint32_t)bp[0] << 24)
136 		| ((uint32_t)bp[1] << 16)
137 		| ((uint32_t)bp[2] << 8)
138 		| bp[3];
139 }
140 
141 static inline void fdt32_st(void *property, uint32_t value)
142 {
143 	uint8_t *bp = (uint8_t *)property;
144 
145 	bp[0] = value >> 24;
146 	bp[1] = (value >> 16) & 0xff;
147 	bp[2] = (value >> 8) & 0xff;
148 	bp[3] = value & 0xff;
149 }
150 
151 static inline uint64_t fdt64_ld(const fdt64_t *p)
152 {
153 	const uint8_t *bp = (const uint8_t *)p;
154 
155 	return ((uint64_t)bp[0] << 56)
156 		| ((uint64_t)bp[1] << 48)
157 		| ((uint64_t)bp[2] << 40)
158 		| ((uint64_t)bp[3] << 32)
159 		| ((uint64_t)bp[4] << 24)
160 		| ((uint64_t)bp[5] << 16)
161 		| ((uint64_t)bp[6] << 8)
162 		| bp[7];
163 }
164 
165 static inline void fdt64_st(void *property, uint64_t value)
166 {
167 	uint8_t *bp = (uint8_t *)property;
168 
169 	bp[0] = value >> 56;
170 	bp[1] = (value >> 48) & 0xff;
171 	bp[2] = (value >> 40) & 0xff;
172 	bp[3] = (value >> 32) & 0xff;
173 	bp[4] = (value >> 24) & 0xff;
174 	bp[5] = (value >> 16) & 0xff;
175 	bp[6] = (value >> 8) & 0xff;
176 	bp[7] = value & 0xff;
177 }
178 
179 /**********************************************************************/
180 /* Traversal functions                                                */
181 /**********************************************************************/
182 
183 int fdt_next_node(const void *fdt, int offset, int *depth);
184 
185 /**
186  * fdt_first_subnode() - get offset of first direct subnode
187  *
188  * @fdt:	FDT blob
189  * @offset:	Offset of node to check
190  * @return offset of first subnode, or -FDT_ERR_NOTFOUND if there is none
191  */
192 int fdt_first_subnode(const void *fdt, int offset);
193 
194 /**
195  * fdt_next_subnode() - get offset of next direct subnode
196  *
197  * After first calling fdt_first_subnode(), call this function repeatedly to
198  * get direct subnodes of a parent node.
199  *
200  * @fdt:	FDT blob
201  * @offset:	Offset of previous subnode
202  * @return offset of next subnode, or -FDT_ERR_NOTFOUND if there are no more
203  * subnodes
204  */
205 int fdt_next_subnode(const void *fdt, int offset);
206 
207 /**
208  * fdt_for_each_subnode - iterate over all subnodes of a parent
209  *
210  * @node:	child node (int, lvalue)
211  * @fdt:	FDT blob (const void *)
212  * @parent:	parent node (int)
213  *
214  * This is actually a wrapper around a for loop and would be used like so:
215  *
216  *	fdt_for_each_subnode(node, fdt, parent) {
217  *		Use node
218  *		...
219  *	}
220  *
221  *	if ((node < 0) && (node != -FDT_ERR_NOTFOUND)) {
222  *		Error handling
223  *	}
224  *
225  * Note that this is implemented as a macro and @node is used as
226  * iterator in the loop. The parent variable be constant or even a
227  * literal.
228  *
229  */
230 #define fdt_for_each_subnode(node, fdt, parent)		\
231 	for (node = fdt_first_subnode(fdt, parent);	\
232 	     node >= 0;					\
233 	     node = fdt_next_subnode(fdt, node))
234 
235 /**********************************************************************/
236 /* General functions                                                  */
237 /**********************************************************************/
238 #define fdt_get_header(fdt, field) \
239 	(fdt32_ld(&((const struct fdt_header *)(fdt))->field))
240 #define fdt_magic(fdt)			(fdt_get_header(fdt, magic))
241 #define fdt_totalsize(fdt)		(fdt_get_header(fdt, totalsize))
242 #define fdt_off_dt_struct(fdt)		(fdt_get_header(fdt, off_dt_struct))
243 #define fdt_off_dt_strings(fdt)		(fdt_get_header(fdt, off_dt_strings))
244 #define fdt_off_mem_rsvmap(fdt)		(fdt_get_header(fdt, off_mem_rsvmap))
245 #define fdt_version(fdt)		(fdt_get_header(fdt, version))
246 #define fdt_last_comp_version(fdt)	(fdt_get_header(fdt, last_comp_version))
247 #define fdt_boot_cpuid_phys(fdt)	(fdt_get_header(fdt, boot_cpuid_phys))
248 #define fdt_size_dt_strings(fdt)	(fdt_get_header(fdt, size_dt_strings))
249 #define fdt_size_dt_struct(fdt)		(fdt_get_header(fdt, size_dt_struct))
250 
251 #define fdt_set_hdr_(name) \
252 	static inline void fdt_set_##name(void *fdt, uint32_t val) \
253 	{ \
254 		struct fdt_header *fdth = (struct fdt_header *)fdt; \
255 		fdth->name = cpu_to_fdt32(val); \
256 	}
257 fdt_set_hdr_(magic);
258 fdt_set_hdr_(totalsize);
259 fdt_set_hdr_(off_dt_struct);
260 fdt_set_hdr_(off_dt_strings);
261 fdt_set_hdr_(off_mem_rsvmap);
262 fdt_set_hdr_(version);
263 fdt_set_hdr_(last_comp_version);
264 fdt_set_hdr_(boot_cpuid_phys);
265 fdt_set_hdr_(size_dt_strings);
266 fdt_set_hdr_(size_dt_struct);
267 #undef fdt_set_hdr_
268 
269 /**
270  * fdt_header_size - return the size of the tree's header
271  * @fdt: pointer to a flattened device tree
272  */
273 size_t fdt_header_size(const void *fdt);
274 
275 /**
276  * fdt_header_size_ - internal function which takes a version number
277  */
278 size_t fdt_header_size_(uint32_t version);
279 
280 /**
281  * fdt_check_header - sanity check a device tree header
282 
283  * @fdt: pointer to data which might be a flattened device tree
284  *
285  * fdt_check_header() checks that the given buffer contains what
286  * appears to be a flattened device tree, and that the header contains
287  * valid information (to the extent that can be determined from the
288  * header alone).
289  *
290  * returns:
291  *     0, if the buffer appears to contain a valid device tree
292  *     -FDT_ERR_BADMAGIC,
293  *     -FDT_ERR_BADVERSION,
294  *     -FDT_ERR_BADSTATE,
295  *     -FDT_ERR_TRUNCATED, standard meanings, as above
296  */
297 int fdt_check_header(const void *fdt);
298 
299 /**
300  * fdt_move - move a device tree around in memory
301  * @fdt: pointer to the device tree to move
302  * @buf: pointer to memory where the device is to be moved
303  * @bufsize: size of the memory space at buf
304  *
305  * fdt_move() relocates, if possible, the device tree blob located at
306  * fdt to the buffer at buf of size bufsize.  The buffer may overlap
307  * with the existing device tree blob at fdt.  Therefore,
308  *     fdt_move(fdt, fdt, fdt_totalsize(fdt))
309  * should always succeed.
310  *
311  * returns:
312  *     0, on success
313  *     -FDT_ERR_NOSPACE, bufsize is insufficient to contain the device tree
314  *     -FDT_ERR_BADMAGIC,
315  *     -FDT_ERR_BADVERSION,
316  *     -FDT_ERR_BADSTATE, standard meanings
317  */
318 int fdt_move(const void *fdt, void *buf, int bufsize);
319 
320 /**********************************************************************/
321 /* Read-only functions                                                */
322 /**********************************************************************/
323 
324 int fdt_check_full(const void *fdt, size_t bufsize);
325 
326 /**
327  * fdt_get_string - retrieve a string from the strings block of a device tree
328  * @fdt: pointer to the device tree blob
329  * @stroffset: offset of the string within the strings block (native endian)
330  * @lenp: optional pointer to return the string's length
331  *
332  * fdt_get_string() retrieves a pointer to a single string from the
333  * strings block of the device tree blob at fdt, and optionally also
334  * returns the string's length in *lenp.
335  *
336  * returns:
337  *     a pointer to the string, on success
338  *     NULL, if stroffset is out of bounds, or doesn't point to a valid string
339  */
340 const char *fdt_get_string(const void *fdt, int stroffset, int *lenp);
341 
342 /**
343  * fdt_string - retrieve a string from the strings block of a device tree
344  * @fdt: pointer to the device tree blob
345  * @stroffset: offset of the string within the strings block (native endian)
346  *
347  * fdt_string() retrieves a pointer to a single string from the
348  * strings block of the device tree blob at fdt.
349  *
350  * returns:
351  *     a pointer to the string, on success
352  *     NULL, if stroffset is out of bounds, or doesn't point to a valid string
353  */
354 const char *fdt_string(const void *fdt, int stroffset);
355 
356 /**
357  * fdt_find_max_phandle - find and return the highest phandle in a tree
358  * @fdt: pointer to the device tree blob
359  * @phandle: return location for the highest phandle value found in the tree
360  *
361  * fdt_find_max_phandle() finds the highest phandle value in the given device
362  * tree. The value returned in @phandle is only valid if the function returns
363  * success.
364  *
365  * returns:
366  *     0 on success or a negative error code on failure
367  */
368 int fdt_find_max_phandle(const void *fdt, uint32_t *phandle);
369 
370 /**
371  * fdt_get_max_phandle - retrieves the highest phandle in a tree
372  * @fdt: pointer to the device tree blob
373  *
374  * fdt_get_max_phandle retrieves the highest phandle in the given
375  * device tree. This will ignore badly formatted phandles, or phandles
376  * with a value of 0 or -1.
377  *
378  * This function is deprecated in favour of fdt_find_max_phandle().
379  *
380  * returns:
381  *      the highest phandle on success
382  *      0, if no phandle was found in the device tree
383  *      -1, if an error occurred
384  */
385 static inline uint32_t fdt_get_max_phandle(const void *fdt)
386 {
387 	uint32_t phandle;
388 	int err;
389 
390 	err = fdt_find_max_phandle(fdt, &phandle);
391 	if (err < 0)
392 		return (uint32_t)-1;
393 
394 	return phandle;
395 }
396 
397 /**
398  * fdt_generate_phandle - return a new, unused phandle for a device tree blob
399  * @fdt: pointer to the device tree blob
400  * @phandle: return location for the new phandle
401  *
402  * Walks the device tree blob and looks for the highest phandle value. On
403  * success, the new, unused phandle value (one higher than the previously
404  * highest phandle value in the device tree blob) will be returned in the
405  * @phandle parameter.
406  *
407  * Returns:
408  *   0 on success or a negative error-code on failure
409  */
410 int fdt_generate_phandle(const void *fdt, uint32_t *phandle);
411 
412 /**
413  * fdt_num_mem_rsv - retrieve the number of memory reserve map entries
414  * @fdt: pointer to the device tree blob
415  *
416  * Returns the number of entries in the device tree blob's memory
417  * reservation map.  This does not include the terminating 0,0 entry
418  * or any other (0,0) entries reserved for expansion.
419  *
420  * returns:
421  *     the number of entries
422  */
423 int fdt_num_mem_rsv(const void *fdt);
424 
425 /**
426  * fdt_get_mem_rsv - retrieve one memory reserve map entry
427  * @fdt: pointer to the device tree blob
428  * @address, @size: pointers to 64-bit variables
429  *
430  * On success, *address and *size will contain the address and size of
431  * the n-th reserve map entry from the device tree blob, in
432  * native-endian format.
433  *
434  * returns:
435  *     0, on success
436  *     -FDT_ERR_BADMAGIC,
437  *     -FDT_ERR_BADVERSION,
438  *     -FDT_ERR_BADSTATE, standard meanings
439  */
440 int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size);
441 
442 /**
443  * fdt_subnode_offset_namelen - find a subnode based on substring
444  * @fdt: pointer to the device tree blob
445  * @parentoffset: structure block offset of a node
446  * @name: name of the subnode to locate
447  * @namelen: number of characters of name to consider
448  *
449  * Identical to fdt_subnode_offset(), but only examine the first
450  * namelen characters of name for matching the subnode name.  This is
451  * useful for finding subnodes based on a portion of a larger string,
452  * such as a full path.
453  */
454 #ifndef SWIG /* Not available in Python */
455 int fdt_subnode_offset_namelen(const void *fdt, int parentoffset,
456 			       const char *name, int namelen);
457 #endif
458 /**
459  * fdt_subnode_offset - find a subnode of a given node
460  * @fdt: pointer to the device tree blob
461  * @parentoffset: structure block offset of a node
462  * @name: name of the subnode to locate
463  *
464  * fdt_subnode_offset() finds a subnode of the node at structure block
465  * offset parentoffset with the given name.  name may include a unit
466  * address, in which case fdt_subnode_offset() will find the subnode
467  * with that unit address, or the unit address may be omitted, in
468  * which case fdt_subnode_offset() will find an arbitrary subnode
469  * whose name excluding unit address matches the given name.
470  *
471  * returns:
472  *	structure block offset of the requested subnode (>=0), on success
473  *	-FDT_ERR_NOTFOUND, if the requested subnode does not exist
474  *	-FDT_ERR_BADOFFSET, if parentoffset did not point to an FDT_BEGIN_NODE
475  *		tag
476  *	-FDT_ERR_BADMAGIC,
477  *	-FDT_ERR_BADVERSION,
478  *	-FDT_ERR_BADSTATE,
479  *	-FDT_ERR_BADSTRUCTURE,
480  *	-FDT_ERR_TRUNCATED, standard meanings.
481  */
482 int fdt_subnode_offset(const void *fdt, int parentoffset, const char *name);
483 
484 /**
485  * fdt_path_offset_namelen - find a tree node by its full path
486  * @fdt: pointer to the device tree blob
487  * @path: full path of the node to locate
488  * @namelen: number of characters of path to consider
489  *
490  * Identical to fdt_path_offset(), but only consider the first namelen
491  * characters of path as the path name.
492  */
493 #ifndef SWIG /* Not available in Python */
494 int fdt_path_offset_namelen(const void *fdt, const char *path, int namelen);
495 #endif
496 
497 /**
498  * fdt_path_offset - find a tree node by its full path
499  * @fdt: pointer to the device tree blob
500  * @path: full path of the node to locate
501  *
502  * fdt_path_offset() finds a node of a given path in the device tree.
503  * Each path component may omit the unit address portion, but the
504  * results of this are undefined if any such path component is
505  * ambiguous (that is if there are multiple nodes at the relevant
506  * level matching the given component, differentiated only by unit
507  * address).
508  *
509  * returns:
510  *	structure block offset of the node with the requested path (>=0), on
511  *		success
512  *	-FDT_ERR_BADPATH, given path does not begin with '/' or is invalid
513  *	-FDT_ERR_NOTFOUND, if the requested node does not exist
514  *      -FDT_ERR_BADMAGIC,
515  *	-FDT_ERR_BADVERSION,
516  *	-FDT_ERR_BADSTATE,
517  *	-FDT_ERR_BADSTRUCTURE,
518  *	-FDT_ERR_TRUNCATED, standard meanings.
519  */
520 int fdt_path_offset(const void *fdt, const char *path);
521 
522 /**
523  * fdt_get_name - retrieve the name of a given node
524  * @fdt: pointer to the device tree blob
525  * @nodeoffset: structure block offset of the starting node
526  * @lenp: pointer to an integer variable (will be overwritten) or NULL
527  *
528  * fdt_get_name() retrieves the name (including unit address) of the
529  * device tree node at structure block offset nodeoffset.  If lenp is
530  * non-NULL, the length of this name is also returned, in the integer
531  * pointed to by lenp.
532  *
533  * returns:
534  *	pointer to the node's name, on success
535  *		If lenp is non-NULL, *lenp contains the length of that name
536  *			(>=0)
537  *	NULL, on error
538  *		if lenp is non-NULL *lenp contains an error code (<0):
539  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
540  *			tag
541  *		-FDT_ERR_BADMAGIC,
542  *		-FDT_ERR_BADVERSION,
543  *		-FDT_ERR_BADSTATE, standard meanings
544  */
545 const char *fdt_get_name(const void *fdt, int nodeoffset, int *lenp);
546 
547 /**
548  * fdt_first_property_offset - find the offset of a node's first property
549  * @fdt: pointer to the device tree blob
550  * @nodeoffset: structure block offset of a node
551  *
552  * fdt_first_property_offset() finds the first property of the node at
553  * the given structure block offset.
554  *
555  * returns:
556  *	structure block offset of the property (>=0), on success
557  *	-FDT_ERR_NOTFOUND, if the requested node has no properties
558  *	-FDT_ERR_BADOFFSET, if nodeoffset did not point to an FDT_BEGIN_NODE tag
559  *      -FDT_ERR_BADMAGIC,
560  *	-FDT_ERR_BADVERSION,
561  *	-FDT_ERR_BADSTATE,
562  *	-FDT_ERR_BADSTRUCTURE,
563  *	-FDT_ERR_TRUNCATED, standard meanings.
564  */
565 int fdt_first_property_offset(const void *fdt, int nodeoffset);
566 
567 /**
568  * fdt_next_property_offset - step through a node's properties
569  * @fdt: pointer to the device tree blob
570  * @offset: structure block offset of a property
571  *
572  * fdt_next_property_offset() finds the property immediately after the
573  * one at the given structure block offset.  This will be a property
574  * of the same node as the given property.
575  *
576  * returns:
577  *	structure block offset of the next property (>=0), on success
578  *	-FDT_ERR_NOTFOUND, if the given property is the last in its node
579  *	-FDT_ERR_BADOFFSET, if nodeoffset did not point to an FDT_PROP tag
580  *      -FDT_ERR_BADMAGIC,
581  *	-FDT_ERR_BADVERSION,
582  *	-FDT_ERR_BADSTATE,
583  *	-FDT_ERR_BADSTRUCTURE,
584  *	-FDT_ERR_TRUNCATED, standard meanings.
585  */
586 int fdt_next_property_offset(const void *fdt, int offset);
587 
588 /**
589  * fdt_for_each_property_offset - iterate over all properties of a node
590  *
591  * @property_offset:	property offset (int, lvalue)
592  * @fdt:		FDT blob (const void *)
593  * @node:		node offset (int)
594  *
595  * This is actually a wrapper around a for loop and would be used like so:
596  *
597  *	fdt_for_each_property_offset(property, fdt, node) {
598  *		Use property
599  *		...
600  *	}
601  *
602  *	if ((property < 0) && (property != -FDT_ERR_NOTFOUND)) {
603  *		Error handling
604  *	}
605  *
606  * Note that this is implemented as a macro and property is used as
607  * iterator in the loop. The node variable can be constant or even a
608  * literal.
609  */
610 #define fdt_for_each_property_offset(property, fdt, node)	\
611 	for (property = fdt_first_property_offset(fdt, node);	\
612 	     property >= 0;					\
613 	     property = fdt_next_property_offset(fdt, property))
614 
615 /**
616  * fdt_get_property_by_offset - retrieve the property at a given offset
617  * @fdt: pointer to the device tree blob
618  * @offset: offset of the property to retrieve
619  * @lenp: pointer to an integer variable (will be overwritten) or NULL
620  *
621  * fdt_get_property_by_offset() retrieves a pointer to the
622  * fdt_property structure within the device tree blob at the given
623  * offset.  If lenp is non-NULL, the length of the property value is
624  * also returned, in the integer pointed to by lenp.
625  *
626  * Note that this code only works on device tree versions >= 16. fdt_getprop()
627  * works on all versions.
628  *
629  * returns:
630  *	pointer to the structure representing the property
631  *		if lenp is non-NULL, *lenp contains the length of the property
632  *		value (>=0)
633  *	NULL, on error
634  *		if lenp is non-NULL, *lenp contains an error code (<0):
635  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_PROP tag
636  *		-FDT_ERR_BADMAGIC,
637  *		-FDT_ERR_BADVERSION,
638  *		-FDT_ERR_BADSTATE,
639  *		-FDT_ERR_BADSTRUCTURE,
640  *		-FDT_ERR_TRUNCATED, standard meanings
641  */
642 const struct fdt_property *fdt_get_property_by_offset(const void *fdt,
643 						      int offset,
644 						      int *lenp);
645 
646 /**
647  * fdt_get_property_namelen - find a property based on substring
648  * @fdt: pointer to the device tree blob
649  * @nodeoffset: offset of the node whose property to find
650  * @name: name of the property to find
651  * @namelen: number of characters of name to consider
652  * @lenp: pointer to an integer variable (will be overwritten) or NULL
653  *
654  * Identical to fdt_get_property(), but only examine the first namelen
655  * characters of name for matching the property name.
656  */
657 #ifndef SWIG /* Not available in Python */
658 const struct fdt_property *fdt_get_property_namelen(const void *fdt,
659 						    int nodeoffset,
660 						    const char *name,
661 						    int namelen, int *lenp);
662 #endif
663 
664 /**
665  * fdt_get_property - find a given property in a given node
666  * @fdt: pointer to the device tree blob
667  * @nodeoffset: offset of the node whose property to find
668  * @name: name of the property to find
669  * @lenp: pointer to an integer variable (will be overwritten) or NULL
670  *
671  * fdt_get_property() retrieves a pointer to the fdt_property
672  * structure within the device tree blob corresponding to the property
673  * named 'name' of the node at offset nodeoffset.  If lenp is
674  * non-NULL, the length of the property value is also returned, in the
675  * integer pointed to by lenp.
676  *
677  * returns:
678  *	pointer to the structure representing the property
679  *		if lenp is non-NULL, *lenp contains the length of the property
680  *		value (>=0)
681  *	NULL, on error
682  *		if lenp is non-NULL, *lenp contains an error code (<0):
683  *		-FDT_ERR_NOTFOUND, node does not have named property
684  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
685  *			tag
686  *		-FDT_ERR_BADMAGIC,
687  *		-FDT_ERR_BADVERSION,
688  *		-FDT_ERR_BADSTATE,
689  *		-FDT_ERR_BADSTRUCTURE,
690  *		-FDT_ERR_TRUNCATED, standard meanings
691  */
692 const struct fdt_property *fdt_get_property(const void *fdt, int nodeoffset,
693 					    const char *name, int *lenp);
694 static inline struct fdt_property *fdt_get_property_w(void *fdt, int nodeoffset,
695 						      const char *name,
696 						      int *lenp)
697 {
698 	return (struct fdt_property *)(uintptr_t)
699 		fdt_get_property(fdt, nodeoffset, name, lenp);
700 }
701 
702 /**
703  * fdt_getprop_by_offset - retrieve the value of a property at a given offset
704  * @fdt: pointer to the device tree blob
705  * @offset: offset of the property to read
706  * @namep: pointer to a string variable (will be overwritten) or NULL
707  * @lenp: pointer to an integer variable (will be overwritten) or NULL
708  *
709  * fdt_getprop_by_offset() retrieves a pointer to the value of the
710  * property at structure block offset 'offset' (this will be a pointer
711  * to within the device blob itself, not a copy of the value).  If
712  * lenp is non-NULL, the length of the property value is also
713  * returned, in the integer pointed to by lenp.  If namep is non-NULL,
714  * the property's namne will also be returned in the char * pointed to
715  * by namep (this will be a pointer to within the device tree's string
716  * block, not a new copy of the name).
717  *
718  * returns:
719  *	pointer to the property's value
720  *		if lenp is non-NULL, *lenp contains the length of the property
721  *		value (>=0)
722  *		if namep is non-NULL *namep contiains a pointer to the property
723  *		name.
724  *	NULL, on error
725  *		if lenp is non-NULL, *lenp contains an error code (<0):
726  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_PROP tag
727  *		-FDT_ERR_BADMAGIC,
728  *		-FDT_ERR_BADVERSION,
729  *		-FDT_ERR_BADSTATE,
730  *		-FDT_ERR_BADSTRUCTURE,
731  *		-FDT_ERR_TRUNCATED, standard meanings
732  */
733 #ifndef SWIG /* This function is not useful in Python */
734 const void *fdt_getprop_by_offset(const void *fdt, int offset,
735 				  const char **namep, int *lenp);
736 #endif
737 
738 /**
739  * fdt_getprop_namelen - get property value based on substring
740  * @fdt: pointer to the device tree blob
741  * @nodeoffset: offset of the node whose property to find
742  * @name: name of the property to find
743  * @namelen: number of characters of name to consider
744  * @lenp: pointer to an integer variable (will be overwritten) or NULL
745  *
746  * Identical to fdt_getprop(), but only examine the first namelen
747  * characters of name for matching the property name.
748  */
749 #ifndef SWIG /* Not available in Python */
750 const void *fdt_getprop_namelen(const void *fdt, int nodeoffset,
751 				const char *name, int namelen, int *lenp);
752 static inline void *fdt_getprop_namelen_w(void *fdt, int nodeoffset,
753 					  const char *name, int namelen,
754 					  int *lenp)
755 {
756 	return (void *)(uintptr_t)fdt_getprop_namelen(fdt, nodeoffset, name,
757 						      namelen, lenp);
758 }
759 #endif
760 
761 /**
762  * fdt_getprop - retrieve the value of a given property
763  * @fdt: pointer to the device tree blob
764  * @nodeoffset: offset of the node whose property to find
765  * @name: name of the property to find
766  * @lenp: pointer to an integer variable (will be overwritten) or NULL
767  *
768  * fdt_getprop() retrieves a pointer to the value of the property
769  * named 'name' of the node at offset nodeoffset (this will be a
770  * pointer to within the device blob itself, not a copy of the value).
771  * If lenp is non-NULL, the length of the property value is also
772  * returned, in the integer pointed to by lenp.
773  *
774  * returns:
775  *	pointer to the property's value
776  *		if lenp is non-NULL, *lenp contains the length of the property
777  *		value (>=0)
778  *	NULL, on error
779  *		if lenp is non-NULL, *lenp contains an error code (<0):
780  *		-FDT_ERR_NOTFOUND, node does not have named property
781  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
782  *			tag
783  *		-FDT_ERR_BADMAGIC,
784  *		-FDT_ERR_BADVERSION,
785  *		-FDT_ERR_BADSTATE,
786  *		-FDT_ERR_BADSTRUCTURE,
787  *		-FDT_ERR_TRUNCATED, standard meanings
788  */
789 const void *fdt_getprop(const void *fdt, int nodeoffset,
790 			const char *name, int *lenp);
791 static inline void *fdt_getprop_w(void *fdt, int nodeoffset,
792 				  const char *name, int *lenp)
793 {
794 	return (void *)(uintptr_t)fdt_getprop(fdt, nodeoffset, name, lenp);
795 }
796 
797 /**
798  * fdt_get_phandle - retrieve the phandle of a given node
799  * @fdt: pointer to the device tree blob
800  * @nodeoffset: structure block offset of the node
801  *
802  * fdt_get_phandle() retrieves the phandle of the device tree node at
803  * structure block offset nodeoffset.
804  *
805  * returns:
806  *	the phandle of the node at nodeoffset, on success (!= 0, != -1)
807  *	0, if the node has no phandle, or another error occurs
808  */
809 uint32_t fdt_get_phandle(const void *fdt, int nodeoffset);
810 
811 /**
812  * fdt_get_alias_namelen - get alias based on substring
813  * @fdt: pointer to the device tree blob
814  * @name: name of the alias th look up
815  * @namelen: number of characters of name to consider
816  *
817  * Identical to fdt_get_alias(), but only examine the first namelen
818  * characters of name for matching the alias name.
819  */
820 #ifndef SWIG /* Not available in Python */
821 const char *fdt_get_alias_namelen(const void *fdt,
822 				  const char *name, int namelen);
823 #endif
824 
825 /**
826  * fdt_get_alias - retrieve the path referenced by a given alias
827  * @fdt: pointer to the device tree blob
828  * @name: name of the alias th look up
829  *
830  * fdt_get_alias() retrieves the value of a given alias.  That is, the
831  * value of the property named 'name' in the node /aliases.
832  *
833  * returns:
834  *	a pointer to the expansion of the alias named 'name', if it exists
835  *	NULL, if the given alias or the /aliases node does not exist
836  */
837 const char *fdt_get_alias(const void *fdt, const char *name);
838 
839 /**
840  * fdt_get_path - determine the full path of a node
841  * @fdt: pointer to the device tree blob
842  * @nodeoffset: offset of the node whose path to find
843  * @buf: character buffer to contain the returned path (will be overwritten)
844  * @buflen: size of the character buffer at buf
845  *
846  * fdt_get_path() computes the full path of the node at offset
847  * nodeoffset, and records that path in the buffer at buf.
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  *	0, on success
854  *		buf contains the absolute path of the node at
855  *		nodeoffset, as a NUL-terminated string.
856  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
857  *	-FDT_ERR_NOSPACE, the path of the given node is longer than (bufsize-1)
858  *		characters and will not fit in the given buffer.
859  *	-FDT_ERR_BADMAGIC,
860  *	-FDT_ERR_BADVERSION,
861  *	-FDT_ERR_BADSTATE,
862  *	-FDT_ERR_BADSTRUCTURE, standard meanings
863  */
864 int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen);
865 
866 /**
867  * fdt_supernode_atdepth_offset - find a specific ancestor of a node
868  * @fdt: pointer to the device tree blob
869  * @nodeoffset: offset of the node whose parent to find
870  * @supernodedepth: depth of the ancestor to find
871  * @nodedepth: pointer to an integer variable (will be overwritten) or NULL
872  *
873  * fdt_supernode_atdepth_offset() finds an ancestor of the given node
874  * at a specific depth from the root (where the root itself has depth
875  * 0, its immediate subnodes depth 1 and so forth).  So
876  *	fdt_supernode_atdepth_offset(fdt, nodeoffset, 0, NULL);
877  * will always return 0, the offset of the root node.  If the node at
878  * nodeoffset has depth D, then:
879  *	fdt_supernode_atdepth_offset(fdt, nodeoffset, D, NULL);
880  * will return nodeoffset itself.
881  *
882  * NOTE: This function is expensive, as it must scan the device tree
883  * structure from the start to nodeoffset.
884  *
885  * returns:
886  *	structure block offset of the node at node offset's ancestor
887  *		of depth supernodedepth (>=0), on success
888  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
889  *	-FDT_ERR_NOTFOUND, supernodedepth was greater than the depth of
890  *		nodeoffset
891  *	-FDT_ERR_BADMAGIC,
892  *	-FDT_ERR_BADVERSION,
893  *	-FDT_ERR_BADSTATE,
894  *	-FDT_ERR_BADSTRUCTURE, standard meanings
895  */
896 int fdt_supernode_atdepth_offset(const void *fdt, int nodeoffset,
897 				 int supernodedepth, int *nodedepth);
898 
899 /**
900  * fdt_node_depth - find the depth of a given node
901  * @fdt: pointer to the device tree blob
902  * @nodeoffset: offset of the node whose parent to find
903  *
904  * fdt_node_depth() finds the depth of a given node.  The root node
905  * has depth 0, its immediate subnodes depth 1 and so forth.
906  *
907  * NOTE: This function is expensive, as it must scan the device tree
908  * structure from the start to nodeoffset.
909  *
910  * returns:
911  *	depth of the node at nodeoffset (>=0), on success
912  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
913  *	-FDT_ERR_BADMAGIC,
914  *	-FDT_ERR_BADVERSION,
915  *	-FDT_ERR_BADSTATE,
916  *	-FDT_ERR_BADSTRUCTURE, standard meanings
917  */
918 int fdt_node_depth(const void *fdt, int nodeoffset);
919 
920 /**
921  * fdt_parent_offset - find the parent of a given node
922  * @fdt: pointer to the device tree blob
923  * @nodeoffset: offset of the node whose parent to find
924  *
925  * fdt_parent_offset() locates the parent node of a given node (that
926  * is, it finds the offset of the node which contains the node at
927  * nodeoffset as a subnode).
928  *
929  * NOTE: This function is expensive, as it must scan the device tree
930  * structure from the start to nodeoffset, *twice*.
931  *
932  * returns:
933  *	structure block offset of the parent of the node at nodeoffset
934  *		(>=0), on success
935  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
936  *	-FDT_ERR_BADMAGIC,
937  *	-FDT_ERR_BADVERSION,
938  *	-FDT_ERR_BADSTATE,
939  *	-FDT_ERR_BADSTRUCTURE, standard meanings
940  */
941 int fdt_parent_offset(const void *fdt, int nodeoffset);
942 
943 /**
944  * fdt_node_offset_by_prop_value - find nodes with a given property value
945  * @fdt: pointer to the device tree blob
946  * @startoffset: only find nodes after this offset
947  * @propname: property name to check
948  * @propval: property value to search for
949  * @proplen: length of the value in propval
950  *
951  * fdt_node_offset_by_prop_value() returns the offset of the first
952  * node after startoffset, which has a property named propname whose
953  * value is of length proplen and has value equal to propval; or if
954  * startoffset is -1, the very first such node in the tree.
955  *
956  * To iterate through all nodes matching the criterion, the following
957  * idiom can be used:
958  *	offset = fdt_node_offset_by_prop_value(fdt, -1, propname,
959  *					       propval, proplen);
960  *	while (offset != -FDT_ERR_NOTFOUND) {
961  *		// other code here
962  *		offset = fdt_node_offset_by_prop_value(fdt, offset, propname,
963  *						       propval, proplen);
964  *	}
965  *
966  * Note the -1 in the first call to the function, if 0 is used here
967  * instead, the function will never locate the root node, even if it
968  * matches the criterion.
969  *
970  * returns:
971  *	structure block offset of the located node (>= 0, >startoffset),
972  *		 on success
973  *	-FDT_ERR_NOTFOUND, no node matching the criterion exists in the
974  *		tree after startoffset
975  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
976  *	-FDT_ERR_BADMAGIC,
977  *	-FDT_ERR_BADVERSION,
978  *	-FDT_ERR_BADSTATE,
979  *	-FDT_ERR_BADSTRUCTURE, standard meanings
980  */
981 int fdt_node_offset_by_prop_value(const void *fdt, int startoffset,
982 				  const char *propname,
983 				  const void *propval, int proplen);
984 
985 /**
986  * fdt_node_offset_by_phandle - find the node with a given phandle
987  * @fdt: pointer to the device tree blob
988  * @phandle: phandle value
989  *
990  * fdt_node_offset_by_phandle() returns the offset of the node
991  * which has the given phandle value.  If there is more than one node
992  * in the tree with the given phandle (an invalid tree), results are
993  * undefined.
994  *
995  * returns:
996  *	structure block offset of the located node (>= 0), on success
997  *	-FDT_ERR_NOTFOUND, no node with that phandle exists
998  *	-FDT_ERR_BADPHANDLE, given phandle value was invalid (0 or -1)
999  *	-FDT_ERR_BADMAGIC,
1000  *	-FDT_ERR_BADVERSION,
1001  *	-FDT_ERR_BADSTATE,
1002  *	-FDT_ERR_BADSTRUCTURE, standard meanings
1003  */
1004 int fdt_node_offset_by_phandle(const void *fdt, uint32_t phandle);
1005 
1006 /**
1007  * fdt_node_check_compatible: check a node's compatible property
1008  * @fdt: pointer to the device tree blob
1009  * @nodeoffset: offset of a tree node
1010  * @compatible: string to match against
1011  *
1012  *
1013  * fdt_node_check_compatible() returns 0 if the given node contains a
1014  * 'compatible' property with the given string as one of its elements,
1015  * it returns non-zero otherwise, or on error.
1016  *
1017  * returns:
1018  *	0, if the node has a 'compatible' property listing the given string
1019  *	1, if the node has a 'compatible' property, but it does not list
1020  *		the given string
1021  *	-FDT_ERR_NOTFOUND, if the given node has no 'compatible' property
1022  *	-FDT_ERR_BADOFFSET, if nodeoffset does not refer to a BEGIN_NODE tag
1023  *	-FDT_ERR_BADMAGIC,
1024  *	-FDT_ERR_BADVERSION,
1025  *	-FDT_ERR_BADSTATE,
1026  *	-FDT_ERR_BADSTRUCTURE, standard meanings
1027  */
1028 int fdt_node_check_compatible(const void *fdt, int nodeoffset,
1029 			      const char *compatible);
1030 
1031 /**
1032  * fdt_node_offset_by_compatible - find nodes with a given 'compatible' value
1033  * @fdt: pointer to the device tree blob
1034  * @startoffset: only find nodes after this offset
1035  * @compatible: 'compatible' string to match against
1036  *
1037  * fdt_node_offset_by_compatible() returns the offset of the first
1038  * node after startoffset, which has a 'compatible' property which
1039  * lists the given compatible string; or if startoffset is -1, the
1040  * very first such node in the tree.
1041  *
1042  * To iterate through all nodes matching the criterion, the following
1043  * idiom can be used:
1044  *	offset = fdt_node_offset_by_compatible(fdt, -1, compatible);
1045  *	while (offset != -FDT_ERR_NOTFOUND) {
1046  *		// other code here
1047  *		offset = fdt_node_offset_by_compatible(fdt, offset, compatible);
1048  *	}
1049  *
1050  * Note the -1 in the first call to the function, if 0 is used here
1051  * instead, the function will never locate the root node, even if it
1052  * matches the criterion.
1053  *
1054  * returns:
1055  *	structure block offset of the located node (>= 0, >startoffset),
1056  *		 on success
1057  *	-FDT_ERR_NOTFOUND, no node matching the criterion exists in the
1058  *		tree after startoffset
1059  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
1060  *	-FDT_ERR_BADMAGIC,
1061  *	-FDT_ERR_BADVERSION,
1062  *	-FDT_ERR_BADSTATE,
1063  *	-FDT_ERR_BADSTRUCTURE, standard meanings
1064  */
1065 int fdt_node_offset_by_compatible(const void *fdt, int startoffset,
1066 				  const char *compatible);
1067 
1068 /**
1069  * fdt_stringlist_contains - check a string list property for a string
1070  * @strlist: Property containing a list of strings to check
1071  * @listlen: Length of property
1072  * @str: String to search for
1073  *
1074  * This is a utility function provided for convenience. The list contains
1075  * one or more strings, each terminated by \0, as is found in a device tree
1076  * "compatible" property.
1077  *
1078  * @return: 1 if the string is found in the list, 0 not found, or invalid list
1079  */
1080 int fdt_stringlist_contains(const char *strlist, int listlen, const char *str);
1081 
1082 /**
1083  * fdt_stringlist_count - count the number of strings in a string list
1084  * @fdt: pointer to the device tree blob
1085  * @nodeoffset: offset of a tree node
1086  * @property: name of the property containing the string list
1087  * @return:
1088  *   the number of strings in the given property
1089  *   -FDT_ERR_BADVALUE if the property value is not NUL-terminated
1090  *   -FDT_ERR_NOTFOUND if the property does not exist
1091  */
1092 int fdt_stringlist_count(const void *fdt, int nodeoffset, const char *property);
1093 
1094 /**
1095  * fdt_stringlist_search - find a string in a string list and return its index
1096  * @fdt: pointer to the device tree blob
1097  * @nodeoffset: offset of a tree node
1098  * @property: name of the property containing the string list
1099  * @string: string to look up in the string list
1100  *
1101  * Note that it is possible for this function to succeed on property values
1102  * that are not NUL-terminated. That's because the function will stop after
1103  * finding the first occurrence of @string. This can for example happen with
1104  * small-valued cell properties, such as #address-cells, when searching for
1105  * the empty string.
1106  *
1107  * @return:
1108  *   the index of the string in the list of strings
1109  *   -FDT_ERR_BADVALUE if the property value is not NUL-terminated
1110  *   -FDT_ERR_NOTFOUND if the property does not exist or does not contain
1111  *                     the given string
1112  */
1113 int fdt_stringlist_search(const void *fdt, int nodeoffset, const char *property,
1114 			  const char *string);
1115 
1116 /**
1117  * fdt_stringlist_get() - obtain the string at a given index in a string list
1118  * @fdt: pointer to the device tree blob
1119  * @nodeoffset: offset of a tree node
1120  * @property: name of the property containing the string list
1121  * @index: index of the string to return
1122  * @lenp: return location for the string length or an error code on failure
1123  *
1124  * Note that this will successfully extract strings from properties with
1125  * non-NUL-terminated values. For example on small-valued cell properties
1126  * this function will return the empty string.
1127  *
1128  * If non-NULL, the length of the string (on success) or a negative error-code
1129  * (on failure) will be stored in the integer pointer to by lenp.
1130  *
1131  * @return:
1132  *   A pointer to the string at the given index in the string list or NULL on
1133  *   failure. On success the length of the string will be stored in the memory
1134  *   location pointed to by the lenp parameter, if non-NULL. On failure one of
1135  *   the following negative error codes will be returned in the lenp parameter
1136  *   (if non-NULL):
1137  *     -FDT_ERR_BADVALUE if the property value is not NUL-terminated
1138  *     -FDT_ERR_NOTFOUND if the property does not exist
1139  */
1140 const char *fdt_stringlist_get(const void *fdt, int nodeoffset,
1141 			       const char *property, int index,
1142 			       int *lenp);
1143 
1144 /**********************************************************************/
1145 /* Read-only functions (addressing related)                           */
1146 /**********************************************************************/
1147 
1148 /**
1149  * FDT_MAX_NCELLS - maximum value for #address-cells and #size-cells
1150  *
1151  * This is the maximum value for #address-cells, #size-cells and
1152  * similar properties that will be processed by libfdt.  IEE1275
1153  * requires that OF implementations handle values up to 4.
1154  * Implementations may support larger values, but in practice higher
1155  * values aren't used.
1156  */
1157 #define FDT_MAX_NCELLS		4
1158 
1159 /**
1160  * fdt_address_cells - retrieve address size for a bus represented in the tree
1161  * @fdt: pointer to the device tree blob
1162  * @nodeoffset: offset of the node to find the address size for
1163  *
1164  * When the node has a valid #address-cells property, returns its value.
1165  *
1166  * returns:
1167  *	0 <= n < FDT_MAX_NCELLS, on success
1168  *      2, if the node has no #address-cells property
1169  *      -FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
1170  *		#address-cells property
1171  *	-FDT_ERR_BADMAGIC,
1172  *	-FDT_ERR_BADVERSION,
1173  *	-FDT_ERR_BADSTATE,
1174  *	-FDT_ERR_BADSTRUCTURE,
1175  *	-FDT_ERR_TRUNCATED, standard meanings
1176  */
1177 int fdt_address_cells(const void *fdt, int nodeoffset);
1178 
1179 /**
1180  * fdt_size_cells - retrieve address range size for a bus represented in the
1181  *                  tree
1182  * @fdt: pointer to the device tree blob
1183  * @nodeoffset: offset of the node to find the address range size for
1184  *
1185  * When the node has a valid #size-cells property, returns its value.
1186  *
1187  * returns:
1188  *	0 <= n < FDT_MAX_NCELLS, on success
1189  *      1, if the node has no #size-cells property
1190  *      -FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
1191  *		#size-cells property
1192  *	-FDT_ERR_BADMAGIC,
1193  *	-FDT_ERR_BADVERSION,
1194  *	-FDT_ERR_BADSTATE,
1195  *	-FDT_ERR_BADSTRUCTURE,
1196  *	-FDT_ERR_TRUNCATED, standard meanings
1197  */
1198 int fdt_size_cells(const void *fdt, int nodeoffset);
1199 
1200 
1201 /**********************************************************************/
1202 /* Write-in-place functions                                           */
1203 /**********************************************************************/
1204 
1205 /**
1206  * fdt_setprop_inplace_namelen_partial - change a property's value,
1207  *                                       but not its size
1208  * @fdt: pointer to the device tree blob
1209  * @nodeoffset: offset of the node whose property to change
1210  * @name: name of the property to change
1211  * @namelen: number of characters of name to consider
1212  * @idx: index of the property to change in the array
1213  * @val: pointer to data to replace the property value with
1214  * @len: length of the property value
1215  *
1216  * Identical to fdt_setprop_inplace(), but modifies the given property
1217  * starting from the given index, and using only the first characters
1218  * of the name. It is useful when you want to manipulate only one value of
1219  * an array and you have a string that doesn't end with \0.
1220  */
1221 #ifndef SWIG /* Not available in Python */
1222 int fdt_setprop_inplace_namelen_partial(void *fdt, int nodeoffset,
1223 					const char *name, int namelen,
1224 					uint32_t idx, const void *val,
1225 					int len);
1226 #endif
1227 
1228 /**
1229  * fdt_setprop_inplace - change a property's value, but not its size
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: pointer to data to replace the property value with
1234  * @len: length of the property value
1235  *
1236  * fdt_setprop_inplace() replaces the value of a given property with
1237  * the data in val, of length len.  This function cannot change the
1238  * size of a property, and so will only work if len is equal to the
1239  * current length of the property.
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 len is not equal to the property's current length
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 #ifndef SWIG /* Not available in Python */
1257 int fdt_setprop_inplace(void *fdt, int nodeoffset, const char *name,
1258 			const void *val, int len);
1259 #endif
1260 
1261 /**
1262  * fdt_setprop_inplace_u32 - change the value of a 32-bit integer property
1263  * @fdt: pointer to the device tree blob
1264  * @nodeoffset: offset of the node whose property to change
1265  * @name: name of the property to change
1266  * @val: 32-bit integer value to replace the property with
1267  *
1268  * fdt_setprop_inplace_u32() replaces the value of a given property
1269  * with the 32-bit integer value in val, converting val to big-endian
1270  * if necessary.  This function cannot change the size of a property,
1271  * and so will only work if the property already exists and has length
1272  * 4.
1273  *
1274  * This function will alter only the bytes in the blob which contain
1275  * the given property value, and will not alter or move any other part
1276  * of the tree.
1277  *
1278  * returns:
1279  *	0, on success
1280  *	-FDT_ERR_NOSPACE, if the property's length is not equal to 4
1281  *	-FDT_ERR_NOTFOUND, node does not have the named property
1282  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1283  *	-FDT_ERR_BADMAGIC,
1284  *	-FDT_ERR_BADVERSION,
1285  *	-FDT_ERR_BADSTATE,
1286  *	-FDT_ERR_BADSTRUCTURE,
1287  *	-FDT_ERR_TRUNCATED, standard meanings
1288  */
1289 static inline int fdt_setprop_inplace_u32(void *fdt, int nodeoffset,
1290 					  const char *name, uint32_t val)
1291 {
1292 	fdt32_t tmp = cpu_to_fdt32(val);
1293 	return fdt_setprop_inplace(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1294 }
1295 
1296 /**
1297  * fdt_setprop_inplace_u64 - change the value of a 64-bit integer property
1298  * @fdt: pointer to the device tree blob
1299  * @nodeoffset: offset of the node whose property to change
1300  * @name: name of the property to change
1301  * @val: 64-bit integer value to replace the property with
1302  *
1303  * fdt_setprop_inplace_u64() replaces the value of a given property
1304  * with the 64-bit integer value in val, converting val to big-endian
1305  * if necessary.  This function cannot change the size of a property,
1306  * and so will only work if the property already exists and has length
1307  * 8.
1308  *
1309  * This function will alter only the bytes in the blob which contain
1310  * the given property value, and will not alter or move any other part
1311  * of the tree.
1312  *
1313  * returns:
1314  *	0, on success
1315  *	-FDT_ERR_NOSPACE, if the property's length is not equal to 8
1316  *	-FDT_ERR_NOTFOUND, node does not have the named property
1317  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1318  *	-FDT_ERR_BADMAGIC,
1319  *	-FDT_ERR_BADVERSION,
1320  *	-FDT_ERR_BADSTATE,
1321  *	-FDT_ERR_BADSTRUCTURE,
1322  *	-FDT_ERR_TRUNCATED, standard meanings
1323  */
1324 static inline int fdt_setprop_inplace_u64(void *fdt, int nodeoffset,
1325 					  const char *name, uint64_t val)
1326 {
1327 	fdt64_t tmp = cpu_to_fdt64(val);
1328 	return fdt_setprop_inplace(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1329 }
1330 
1331 /**
1332  * fdt_setprop_inplace_cell - change the value of a single-cell property
1333  *
1334  * This is an alternative name for fdt_setprop_inplace_u32()
1335  */
1336 static inline int fdt_setprop_inplace_cell(void *fdt, int nodeoffset,
1337 					   const char *name, uint32_t val)
1338 {
1339 	return fdt_setprop_inplace_u32(fdt, nodeoffset, name, val);
1340 }
1341 
1342 /**
1343  * fdt_nop_property - replace a property with nop tags
1344  * @fdt: pointer to the device tree blob
1345  * @nodeoffset: offset of the node whose property to nop
1346  * @name: name of the property to nop
1347  *
1348  * fdt_nop_property() will replace a given property's representation
1349  * in the blob with FDT_NOP tags, effectively removing it from the
1350  * tree.
1351  *
1352  * This function will alter only the bytes in the blob which contain
1353  * the property, and will not alter or move any other part of the
1354  * tree.
1355  *
1356  * returns:
1357  *	0, on success
1358  *	-FDT_ERR_NOTFOUND, node does not have the named property
1359  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1360  *	-FDT_ERR_BADMAGIC,
1361  *	-FDT_ERR_BADVERSION,
1362  *	-FDT_ERR_BADSTATE,
1363  *	-FDT_ERR_BADSTRUCTURE,
1364  *	-FDT_ERR_TRUNCATED, standard meanings
1365  */
1366 int fdt_nop_property(void *fdt, int nodeoffset, const char *name);
1367 
1368 /**
1369  * fdt_nop_node - replace a node (subtree) with nop tags
1370  * @fdt: pointer to the device tree blob
1371  * @nodeoffset: offset of the node to nop
1372  *
1373  * fdt_nop_node() will replace a given node's representation in the
1374  * blob, including all its subnodes, if any, with FDT_NOP tags,
1375  * effectively removing it from the tree.
1376  *
1377  * This function will alter only the bytes in the blob which contain
1378  * the node and its properties and subnodes, and will not alter or
1379  * move any other part of the tree.
1380  *
1381  * returns:
1382  *	0, on success
1383  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1384  *	-FDT_ERR_BADMAGIC,
1385  *	-FDT_ERR_BADVERSION,
1386  *	-FDT_ERR_BADSTATE,
1387  *	-FDT_ERR_BADSTRUCTURE,
1388  *	-FDT_ERR_TRUNCATED, standard meanings
1389  */
1390 int fdt_nop_node(void *fdt, int nodeoffset);
1391 
1392 /**********************************************************************/
1393 /* Sequential write functions                                         */
1394 /**********************************************************************/
1395 
1396 /* fdt_create_with_flags flags */
1397 #define FDT_CREATE_FLAG_NO_NAME_DEDUP 0x1
1398 	/* FDT_CREATE_FLAG_NO_NAME_DEDUP: Do not try to de-duplicate property
1399 	 * names in the fdt. This can result in faster creation times, but
1400 	 * a larger fdt. */
1401 
1402 #define FDT_CREATE_FLAGS_ALL	(FDT_CREATE_FLAG_NO_NAME_DEDUP)
1403 
1404 /**
1405  * fdt_create_with_flags - begin creation of a new fdt
1406  * @fdt: pointer to memory allocated where fdt will be created
1407  * @bufsize: size of the memory space at fdt
1408  * @flags: a valid combination of FDT_CREATE_FLAG_ flags, or 0.
1409  *
1410  * fdt_create_with_flags() begins the process of creating a new fdt with
1411  * the sequential write interface.
1412  *
1413  * fdt creation process must end with fdt_finished() to produce a valid fdt.
1414  *
1415  * returns:
1416  *	0, on success
1417  *	-FDT_ERR_NOSPACE, bufsize is insufficient for a minimal fdt
1418  *	-FDT_ERR_BADFLAGS, flags is not valid
1419  */
1420 int fdt_create_with_flags(void *buf, int bufsize, uint32_t flags);
1421 
1422 /**
1423  * fdt_create - begin creation of a new fdt
1424  * @fdt: pointer to memory allocated where fdt will be created
1425  * @bufsize: size of the memory space at fdt
1426  *
1427  * fdt_create() is equivalent to fdt_create_with_flags() with flags=0.
1428  *
1429  * returns:
1430  *	0, on success
1431  *	-FDT_ERR_NOSPACE, bufsize is insufficient for a minimal fdt
1432  */
1433 int fdt_create(void *buf, int bufsize);
1434 
1435 int fdt_resize(void *fdt, void *buf, int bufsize);
1436 int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size);
1437 int fdt_finish_reservemap(void *fdt);
1438 int fdt_begin_node(void *fdt, const char *name);
1439 int fdt_property(void *fdt, const char *name, const void *val, int len);
1440 static inline int fdt_property_u32(void *fdt, const char *name, uint32_t val)
1441 {
1442 	fdt32_t tmp = cpu_to_fdt32(val);
1443 	return fdt_property(fdt, name, &tmp, sizeof(tmp));
1444 }
1445 static inline int fdt_property_u64(void *fdt, const char *name, uint64_t val)
1446 {
1447 	fdt64_t tmp = cpu_to_fdt64(val);
1448 	return fdt_property(fdt, name, &tmp, sizeof(tmp));
1449 }
1450 
1451 #ifndef SWIG /* Not available in Python */
1452 static inline int fdt_property_cell(void *fdt, const char *name, uint32_t val)
1453 {
1454 	return fdt_property_u32(fdt, name, val);
1455 }
1456 #endif
1457 
1458 /**
1459  * fdt_property_placeholder - add a new property and return a ptr to its value
1460  *
1461  * @fdt: pointer to the device tree blob
1462  * @name: name of property to add
1463  * @len: length of property value in bytes
1464  * @valp: returns a pointer to where where the value should be placed
1465  *
1466  * returns:
1467  *	0, on success
1468  *	-FDT_ERR_BADMAGIC,
1469  *	-FDT_ERR_NOSPACE, standard meanings
1470  */
1471 int fdt_property_placeholder(void *fdt, const char *name, int len, void **valp);
1472 
1473 #define fdt_property_string(fdt, name, str) \
1474 	fdt_property(fdt, name, str, strlen(str)+1)
1475 int fdt_end_node(void *fdt);
1476 int fdt_finish(void *fdt);
1477 
1478 /**********************************************************************/
1479 /* Read-write functions                                               */
1480 /**********************************************************************/
1481 
1482 int fdt_create_empty_tree(void *buf, int bufsize);
1483 int fdt_open_into(const void *fdt, void *buf, int bufsize);
1484 int fdt_pack(void *fdt);
1485 
1486 /**
1487  * fdt_add_mem_rsv - add one memory reserve map entry
1488  * @fdt: pointer to the device tree blob
1489  * @address, @size: 64-bit values (native endian)
1490  *
1491  * Adds a reserve map entry to the given blob reserving a region at
1492  * address address of length size.
1493  *
1494  * This function will insert data into the reserve map and will
1495  * therefore change the indexes of some entries in the table.
1496  *
1497  * returns:
1498  *	0, on success
1499  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1500  *		contain the new reservation entry
1501  *	-FDT_ERR_BADMAGIC,
1502  *	-FDT_ERR_BADVERSION,
1503  *	-FDT_ERR_BADSTATE,
1504  *	-FDT_ERR_BADSTRUCTURE,
1505  *	-FDT_ERR_BADLAYOUT,
1506  *	-FDT_ERR_TRUNCATED, standard meanings
1507  */
1508 int fdt_add_mem_rsv(void *fdt, uint64_t address, uint64_t size);
1509 
1510 /**
1511  * fdt_del_mem_rsv - remove a memory reserve map entry
1512  * @fdt: pointer to the device tree blob
1513  * @n: entry to remove
1514  *
1515  * fdt_del_mem_rsv() removes the n-th memory reserve map entry from
1516  * the blob.
1517  *
1518  * This function will delete data from the reservation table and will
1519  * therefore change the indexes of some entries in the table.
1520  *
1521  * returns:
1522  *	0, on success
1523  *	-FDT_ERR_NOTFOUND, there is no entry of the given index (i.e. there
1524  *		are less than n+1 reserve map entries)
1525  *	-FDT_ERR_BADMAGIC,
1526  *	-FDT_ERR_BADVERSION,
1527  *	-FDT_ERR_BADSTATE,
1528  *	-FDT_ERR_BADSTRUCTURE,
1529  *	-FDT_ERR_BADLAYOUT,
1530  *	-FDT_ERR_TRUNCATED, standard meanings
1531  */
1532 int fdt_del_mem_rsv(void *fdt, int n);
1533 
1534 /**
1535  * fdt_set_name - change the name of a given node
1536  * @fdt: pointer to the device tree blob
1537  * @nodeoffset: structure block offset of a node
1538  * @name: name to give the node
1539  *
1540  * fdt_set_name() replaces the name (including unit address, if any)
1541  * of the given node with the given string.  NOTE: this function can't
1542  * efficiently check if the new name is unique amongst the given
1543  * node's siblings; results are undefined if this function is invoked
1544  * with a name equal to one of the given node's siblings.
1545  *
1546  * This function may insert or delete data from the blob, and will
1547  * therefore change the offsets of some existing nodes.
1548  *
1549  * returns:
1550  *	0, on success
1551  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob
1552  *		to contain the new name
1553  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1554  *	-FDT_ERR_BADMAGIC,
1555  *	-FDT_ERR_BADVERSION,
1556  *	-FDT_ERR_BADSTATE, standard meanings
1557  */
1558 int fdt_set_name(void *fdt, int nodeoffset, const char *name);
1559 
1560 /**
1561  * fdt_setprop - create or change a property
1562  * @fdt: pointer to the device tree blob
1563  * @nodeoffset: offset of the node whose property to change
1564  * @name: name of the property to change
1565  * @val: pointer to data to set the property value to
1566  * @len: length of the property value
1567  *
1568  * fdt_setprop() sets the value of the named property in the given
1569  * node to the given value and length, creating the property if it
1570  * does not already exist.
1571  *
1572  * This function may insert or delete data from the blob, and will
1573  * therefore change the offsets of some existing nodes.
1574  *
1575  * returns:
1576  *	0, on success
1577  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1578  *		contain the new property value
1579  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1580  *	-FDT_ERR_BADLAYOUT,
1581  *	-FDT_ERR_BADMAGIC,
1582  *	-FDT_ERR_BADVERSION,
1583  *	-FDT_ERR_BADSTATE,
1584  *	-FDT_ERR_BADSTRUCTURE,
1585  *	-FDT_ERR_BADLAYOUT,
1586  *	-FDT_ERR_TRUNCATED, standard meanings
1587  */
1588 int fdt_setprop(void *fdt, int nodeoffset, const char *name,
1589 		const void *val, int len);
1590 
1591 /**
1592  * fdt_setprop_placeholder - allocate space for a property
1593  * @fdt: pointer to the device tree blob
1594  * @nodeoffset: offset of the node whose property to change
1595  * @name: name of the property to change
1596  * @len: length of the property value
1597  * @prop_data: return pointer to property data
1598  *
1599  * fdt_setprop_placeholer() allocates the named property in the given node.
1600  * If the property exists it is resized. In either case a pointer to the
1601  * property data is returned.
1602  *
1603  * This function may insert or delete data from the blob, and will
1604  * therefore change the offsets of some existing nodes.
1605  *
1606  * returns:
1607  *	0, on success
1608  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1609  *		contain the new property value
1610  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1611  *	-FDT_ERR_BADLAYOUT,
1612  *	-FDT_ERR_BADMAGIC,
1613  *	-FDT_ERR_BADVERSION,
1614  *	-FDT_ERR_BADSTATE,
1615  *	-FDT_ERR_BADSTRUCTURE,
1616  *	-FDT_ERR_BADLAYOUT,
1617  *	-FDT_ERR_TRUNCATED, standard meanings
1618  */
1619 int fdt_setprop_placeholder(void *fdt, int nodeoffset, const char *name,
1620 			    int len, void **prop_data);
1621 
1622 /**
1623  * fdt_setprop_u32 - set a property to a 32-bit integer
1624  * @fdt: pointer to the device tree blob
1625  * @nodeoffset: offset of the node whose property to change
1626  * @name: name of the property to change
1627  * @val: 32-bit integer value for the property (native endian)
1628  *
1629  * fdt_setprop_u32() sets the value of the named property in the given
1630  * node to the given 32-bit integer value (converting to big-endian if
1631  * necessary), or creates a new property with that value if it does
1632  * not already exist.
1633  *
1634  * This function may insert or delete data from the blob, and will
1635  * therefore change the offsets of some existing nodes.
1636  *
1637  * returns:
1638  *	0, on success
1639  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1640  *		contain the new property value
1641  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1642  *	-FDT_ERR_BADLAYOUT,
1643  *	-FDT_ERR_BADMAGIC,
1644  *	-FDT_ERR_BADVERSION,
1645  *	-FDT_ERR_BADSTATE,
1646  *	-FDT_ERR_BADSTRUCTURE,
1647  *	-FDT_ERR_BADLAYOUT,
1648  *	-FDT_ERR_TRUNCATED, standard meanings
1649  */
1650 static inline int fdt_setprop_u32(void *fdt, int nodeoffset, const char *name,
1651 				  uint32_t val)
1652 {
1653 	fdt32_t tmp = cpu_to_fdt32(val);
1654 	return fdt_setprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1655 }
1656 
1657 /**
1658  * fdt_setprop_u64 - set a property to a 64-bit integer
1659  * @fdt: pointer to the device tree blob
1660  * @nodeoffset: offset of the node whose property to change
1661  * @name: name of the property to change
1662  * @val: 64-bit integer value for the property (native endian)
1663  *
1664  * fdt_setprop_u64() sets the value of the named property in the given
1665  * node to the given 64-bit integer value (converting to big-endian if
1666  * necessary), or creates a new property with that value if it does
1667  * not already exist.
1668  *
1669  * This function may insert or delete data from the blob, and will
1670  * therefore change the offsets of some existing nodes.
1671  *
1672  * returns:
1673  *	0, on success
1674  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1675  *		contain the new property value
1676  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1677  *	-FDT_ERR_BADLAYOUT,
1678  *	-FDT_ERR_BADMAGIC,
1679  *	-FDT_ERR_BADVERSION,
1680  *	-FDT_ERR_BADSTATE,
1681  *	-FDT_ERR_BADSTRUCTURE,
1682  *	-FDT_ERR_BADLAYOUT,
1683  *	-FDT_ERR_TRUNCATED, standard meanings
1684  */
1685 static inline int fdt_setprop_u64(void *fdt, int nodeoffset, const char *name,
1686 				  uint64_t val)
1687 {
1688 	fdt64_t tmp = cpu_to_fdt64(val);
1689 	return fdt_setprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1690 }
1691 
1692 /**
1693  * fdt_setprop_cell - set a property to a single cell value
1694  *
1695  * This is an alternative name for fdt_setprop_u32()
1696  */
1697 static inline int fdt_setprop_cell(void *fdt, int nodeoffset, const char *name,
1698 				   uint32_t val)
1699 {
1700 	return fdt_setprop_u32(fdt, nodeoffset, name, val);
1701 }
1702 
1703 /**
1704  * fdt_setprop_string - set a property to a string value
1705  * @fdt: pointer to the device tree blob
1706  * @nodeoffset: offset of the node whose property to change
1707  * @name: name of the property to change
1708  * @str: string value for the property
1709  *
1710  * fdt_setprop_string() sets the value of the named property in the
1711  * given node to the given string value (using the length of the
1712  * string to determine the new length of the property), or creates a
1713  * new property with that value if it does not already exist.
1714  *
1715  * This function may insert or delete data from the blob, and will
1716  * therefore change the offsets of some existing nodes.
1717  *
1718  * returns:
1719  *	0, on success
1720  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1721  *		contain the new property value
1722  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1723  *	-FDT_ERR_BADLAYOUT,
1724  *	-FDT_ERR_BADMAGIC,
1725  *	-FDT_ERR_BADVERSION,
1726  *	-FDT_ERR_BADSTATE,
1727  *	-FDT_ERR_BADSTRUCTURE,
1728  *	-FDT_ERR_BADLAYOUT,
1729  *	-FDT_ERR_TRUNCATED, standard meanings
1730  */
1731 #define fdt_setprop_string(fdt, nodeoffset, name, str) \
1732 	fdt_setprop((fdt), (nodeoffset), (name), (str), strlen(str)+1)
1733 
1734 
1735 /**
1736  * fdt_setprop_empty - set a property to an empty value
1737  * @fdt: pointer to the device tree blob
1738  * @nodeoffset: offset of the node whose property to change
1739  * @name: name of the property to change
1740  *
1741  * fdt_setprop_empty() sets the value of the named property in the
1742  * given node to an empty (zero length) value, or creates a new empty
1743  * property if it does not already exist.
1744  *
1745  * This function may insert or delete data from the blob, and will
1746  * therefore change the offsets of some existing nodes.
1747  *
1748  * returns:
1749  *	0, on success
1750  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1751  *		contain the new property value
1752  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1753  *	-FDT_ERR_BADLAYOUT,
1754  *	-FDT_ERR_BADMAGIC,
1755  *	-FDT_ERR_BADVERSION,
1756  *	-FDT_ERR_BADSTATE,
1757  *	-FDT_ERR_BADSTRUCTURE,
1758  *	-FDT_ERR_BADLAYOUT,
1759  *	-FDT_ERR_TRUNCATED, standard meanings
1760  */
1761 #define fdt_setprop_empty(fdt, nodeoffset, name) \
1762 	fdt_setprop((fdt), (nodeoffset), (name), NULL, 0)
1763 
1764 /**
1765  * fdt_appendprop - append to or create a property
1766  * @fdt: pointer to the device tree blob
1767  * @nodeoffset: offset of the node whose property to change
1768  * @name: name of the property to append to
1769  * @val: pointer to data to append to the property value
1770  * @len: length of the data to append to the property value
1771  *
1772  * fdt_appendprop() appends the value to the named property in the
1773  * given node, creating the property if it does not already exist.
1774  *
1775  * This function may insert data into the blob, and will therefore
1776  * change the offsets of some existing nodes.
1777  *
1778  * returns:
1779  *	0, on success
1780  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1781  *		contain the new property value
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_BADLAYOUT,
1789  *	-FDT_ERR_TRUNCATED, standard meanings
1790  */
1791 int fdt_appendprop(void *fdt, int nodeoffset, const char *name,
1792 		   const void *val, int len);
1793 
1794 /**
1795  * fdt_appendprop_u32 - append a 32-bit integer value to a property
1796  * @fdt: pointer to the device tree blob
1797  * @nodeoffset: offset of the node whose property to change
1798  * @name: name of the property to change
1799  * @val: 32-bit integer value to append to the property (native endian)
1800  *
1801  * fdt_appendprop_u32() appends the given 32-bit integer value
1802  * (converting to big-endian if necessary) to the value of the named
1803  * property in the given node, or creates a new property with that
1804  * value if it does not already exist.
1805  *
1806  * This function may insert data into the blob, and will therefore
1807  * change the offsets of some existing nodes.
1808  *
1809  * returns:
1810  *	0, on success
1811  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1812  *		contain the new property value
1813  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1814  *	-FDT_ERR_BADLAYOUT,
1815  *	-FDT_ERR_BADMAGIC,
1816  *	-FDT_ERR_BADVERSION,
1817  *	-FDT_ERR_BADSTATE,
1818  *	-FDT_ERR_BADSTRUCTURE,
1819  *	-FDT_ERR_BADLAYOUT,
1820  *	-FDT_ERR_TRUNCATED, standard meanings
1821  */
1822 static inline int fdt_appendprop_u32(void *fdt, int nodeoffset,
1823 				     const char *name, uint32_t val)
1824 {
1825 	fdt32_t tmp = cpu_to_fdt32(val);
1826 	return fdt_appendprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1827 }
1828 
1829 /**
1830  * fdt_appendprop_u64 - append a 64-bit integer value to a property
1831  * @fdt: pointer to the device tree blob
1832  * @nodeoffset: offset of the node whose property to change
1833  * @name: name of the property to change
1834  * @val: 64-bit integer value to append to the property (native endian)
1835  *
1836  * fdt_appendprop_u64() appends the given 64-bit integer value
1837  * (converting to big-endian if necessary) to the value of the named
1838  * property in the given node, or creates a new property with that
1839  * value if it does not already exist.
1840  *
1841  * This function may insert data into the blob, and will therefore
1842  * change the offsets of some existing nodes.
1843  *
1844  * returns:
1845  *	0, on success
1846  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1847  *		contain the new property value
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_BADLAYOUT,
1855  *	-FDT_ERR_TRUNCATED, standard meanings
1856  */
1857 static inline int fdt_appendprop_u64(void *fdt, int nodeoffset,
1858 				     const char *name, uint64_t val)
1859 {
1860 	fdt64_t tmp = cpu_to_fdt64(val);
1861 	return fdt_appendprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1862 }
1863 
1864 /**
1865  * fdt_appendprop_cell - append a single cell value to a property
1866  *
1867  * This is an alternative name for fdt_appendprop_u32()
1868  */
1869 static inline int fdt_appendprop_cell(void *fdt, int nodeoffset,
1870 				      const char *name, uint32_t val)
1871 {
1872 	return fdt_appendprop_u32(fdt, nodeoffset, name, val);
1873 }
1874 
1875 /**
1876  * fdt_appendprop_string - append a string to a property
1877  * @fdt: pointer to the device tree blob
1878  * @nodeoffset: offset of the node whose property to change
1879  * @name: name of the property to change
1880  * @str: string value to append to the property
1881  *
1882  * fdt_appendprop_string() appends the given string to the value of
1883  * the named property in the given node, or creates a new property
1884  * with that value if it does not already exist.
1885  *
1886  * This function may insert data into the blob, and will therefore
1887  * change the offsets of some existing nodes.
1888  *
1889  * returns:
1890  *	0, on success
1891  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1892  *		contain the new property value
1893  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1894  *	-FDT_ERR_BADLAYOUT,
1895  *	-FDT_ERR_BADMAGIC,
1896  *	-FDT_ERR_BADVERSION,
1897  *	-FDT_ERR_BADSTATE,
1898  *	-FDT_ERR_BADSTRUCTURE,
1899  *	-FDT_ERR_BADLAYOUT,
1900  *	-FDT_ERR_TRUNCATED, standard meanings
1901  */
1902 #define fdt_appendprop_string(fdt, nodeoffset, name, str) \
1903 	fdt_appendprop((fdt), (nodeoffset), (name), (str), strlen(str)+1)
1904 
1905 /**
1906  * fdt_appendprop_addrrange - append a address range property
1907  * @fdt: pointer to the device tree blob
1908  * @parent: offset of the parent node
1909  * @nodeoffset: offset of the node to add a property at
1910  * @name: name of property
1911  * @addr: start address of a given range
1912  * @size: size of a given range
1913  *
1914  * fdt_appendprop_addrrange() appends an address range value (start
1915  * address and size) to the value of the named property in the given
1916  * node, or creates a new property with that value if it does not
1917  * already exist.
1918  * If "name" is not specified, a default "reg" is used.
1919  * Cell sizes are determined by parent's #address-cells and #size-cells.
1920  *
1921  * This function may insert data into the blob, and will therefore
1922  * change the offsets of some existing nodes.
1923  *
1924  * returns:
1925  *	0, on success
1926  *	-FDT_ERR_BADLAYOUT,
1927  *	-FDT_ERR_BADMAGIC,
1928  *	-FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
1929  *		#address-cells property
1930  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1931  *	-FDT_ERR_BADSTATE,
1932  *	-FDT_ERR_BADSTRUCTURE,
1933  *	-FDT_ERR_BADVERSION,
1934  *	-FDT_ERR_BADVALUE, addr or size doesn't fit to respective cells size
1935  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1936  *		contain a new property
1937  *	-FDT_ERR_TRUNCATED, standard meanings
1938  */
1939 int fdt_appendprop_addrrange(void *fdt, int parent, int nodeoffset,
1940 			     const char *name, uint64_t addr, uint64_t size);
1941 
1942 /**
1943  * fdt_delprop - delete a property
1944  * @fdt: pointer to the device tree blob
1945  * @nodeoffset: offset of the node whose property to nop
1946  * @name: name of the property to nop
1947  *
1948  * fdt_del_property() will delete the given property.
1949  *
1950  * This function will delete data from the blob, and will therefore
1951  * change the offsets of some existing nodes.
1952  *
1953  * returns:
1954  *	0, on success
1955  *	-FDT_ERR_NOTFOUND, node does not have the named property
1956  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1957  *	-FDT_ERR_BADLAYOUT,
1958  *	-FDT_ERR_BADMAGIC,
1959  *	-FDT_ERR_BADVERSION,
1960  *	-FDT_ERR_BADSTATE,
1961  *	-FDT_ERR_BADSTRUCTURE,
1962  *	-FDT_ERR_TRUNCATED, standard meanings
1963  */
1964 int fdt_delprop(void *fdt, int nodeoffset, const char *name);
1965 
1966 /**
1967  * fdt_add_subnode_namelen - creates a new node based on substring
1968  * @fdt: pointer to the device tree blob
1969  * @parentoffset: structure block offset of a node
1970  * @name: name of the subnode to locate
1971  * @namelen: number of characters of name to consider
1972  *
1973  * Identical to fdt_add_subnode(), but use only the first namelen
1974  * characters of name as the name of the new node.  This is useful for
1975  * creating subnodes based on a portion of a larger string, such as a
1976  * full path.
1977  */
1978 #ifndef SWIG /* Not available in Python */
1979 int fdt_add_subnode_namelen(void *fdt, int parentoffset,
1980 			    const char *name, int namelen);
1981 #endif
1982 
1983 /**
1984  * fdt_add_subnode - creates a new node
1985  * @fdt: pointer to the device tree blob
1986  * @parentoffset: structure block offset of a node
1987  * @name: name of the subnode to locate
1988  *
1989  * fdt_add_subnode() creates a new node as a subnode of the node at
1990  * structure block offset parentoffset, with the given name (which
1991  * should include the unit address, if any).
1992  *
1993  * This function will insert data into the blob, and will therefore
1994  * change the offsets of some existing nodes.
1995 
1996  * returns:
1997  *	structure block offset of the created nodeequested subnode (>=0), on
1998  *		success
1999  *	-FDT_ERR_NOTFOUND, if the requested subnode does not exist
2000  *	-FDT_ERR_BADOFFSET, if parentoffset did not point to an FDT_BEGIN_NODE
2001  *		tag
2002  *	-FDT_ERR_EXISTS, if the node at parentoffset already has a subnode of
2003  *		the given name
2004  *	-FDT_ERR_NOSPACE, if there is insufficient free space in the
2005  *		blob to contain the new node
2006  *	-FDT_ERR_NOSPACE
2007  *	-FDT_ERR_BADLAYOUT
2008  *      -FDT_ERR_BADMAGIC,
2009  *	-FDT_ERR_BADVERSION,
2010  *	-FDT_ERR_BADSTATE,
2011  *	-FDT_ERR_BADSTRUCTURE,
2012  *	-FDT_ERR_TRUNCATED, standard meanings.
2013  */
2014 int fdt_add_subnode(void *fdt, int parentoffset, const char *name);
2015 
2016 /**
2017  * fdt_del_node - delete a node (subtree)
2018  * @fdt: pointer to the device tree blob
2019  * @nodeoffset: offset of the node to nop
2020  *
2021  * fdt_del_node() will remove the given node, including all its
2022  * subnodes if any, from the blob.
2023  *
2024  * This function will delete data from the blob, and will therefore
2025  * change the offsets of some existing nodes.
2026  *
2027  * returns:
2028  *	0, on success
2029  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
2030  *	-FDT_ERR_BADLAYOUT,
2031  *	-FDT_ERR_BADMAGIC,
2032  *	-FDT_ERR_BADVERSION,
2033  *	-FDT_ERR_BADSTATE,
2034  *	-FDT_ERR_BADSTRUCTURE,
2035  *	-FDT_ERR_TRUNCATED, standard meanings
2036  */
2037 int fdt_del_node(void *fdt, int nodeoffset);
2038 
2039 /**
2040  * fdt_overlay_apply - Applies a DT overlay on a base DT
2041  * @fdt: pointer to the base device tree blob
2042  * @fdto: pointer to the device tree overlay blob
2043  *
2044  * fdt_overlay_apply() will apply the given device tree overlay on the
2045  * given base device tree.
2046  *
2047  * Expect the base device tree to be modified, even if the function
2048  * returns an error.
2049  *
2050  * returns:
2051  *	0, on success
2052  *	-FDT_ERR_NOSPACE, there's not enough space in the base device tree
2053  *	-FDT_ERR_NOTFOUND, the overlay points to some inexistant nodes or
2054  *		properties in the base DT
2055  *	-FDT_ERR_BADPHANDLE,
2056  *	-FDT_ERR_BADOVERLAY,
2057  *	-FDT_ERR_NOPHANDLES,
2058  *	-FDT_ERR_INTERNAL,
2059  *	-FDT_ERR_BADLAYOUT,
2060  *	-FDT_ERR_BADMAGIC,
2061  *	-FDT_ERR_BADOFFSET,
2062  *	-FDT_ERR_BADPATH,
2063  *	-FDT_ERR_BADVERSION,
2064  *	-FDT_ERR_BADSTRUCTURE,
2065  *	-FDT_ERR_BADSTATE,
2066  *	-FDT_ERR_TRUNCATED, standard meanings
2067  */
2068 int fdt_overlay_apply(void *fdt, void *fdto);
2069 
2070 /**********************************************************************/
2071 /* Debugging / informational functions                                */
2072 /**********************************************************************/
2073 
2074 const char *fdt_strerror(int errval);
2075 
2076 #ifdef __cplusplus
2077 }
2078 #endif
2079 
2080 #endif /* LIBFDT_H */
2081