xref: /linux/scripts/dtc/libfdt/libfdt.h (revision 0da908c291070d89482f6211dbe81d4d43c3f7cb)
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_COMPATIBLE_VERSION 0x10
18 #define FDT_LAST_SUPPORTED_VERSION	0x11
19 
20 /* Error codes: informative error codes */
21 #define FDT_ERR_NOTFOUND	1
22 	/* FDT_ERR_NOTFOUND: The requested node or property does not exist */
23 #define FDT_ERR_EXISTS		2
24 	/* FDT_ERR_EXISTS: Attempted to create a node or property which
25 	 * already exists */
26 #define FDT_ERR_NOSPACE		3
27 	/* FDT_ERR_NOSPACE: Operation needed to expand the device
28 	 * tree, but its buffer did not have sufficient space to
29 	 * contain the expanded tree. Use fdt_open_into() to move the
30 	 * device tree to a buffer with more space. */
31 
32 /* Error codes: codes for bad parameters */
33 #define FDT_ERR_BADOFFSET	4
34 	/* FDT_ERR_BADOFFSET: Function was passed a structure block
35 	 * offset which is out-of-bounds, or which points to an
36 	 * unsuitable part of the structure for the operation. */
37 #define FDT_ERR_BADPATH		5
38 	/* FDT_ERR_BADPATH: Function was passed a badly formatted path
39 	 * (e.g. missing a leading / for a function which requires an
40 	 * absolute path) */
41 #define FDT_ERR_BADPHANDLE	6
42 	/* FDT_ERR_BADPHANDLE: Function was passed an invalid phandle.
43 	 * This can be caused either by an invalid phandle property
44 	 * length, or the phandle value was either 0 or -1, which are
45 	 * not permitted. */
46 #define FDT_ERR_BADSTATE	7
47 	/* FDT_ERR_BADSTATE: Function was passed an incomplete device
48 	 * tree created by the sequential-write functions, which is
49 	 * not sufficiently complete for the requested operation. */
50 
51 /* Error codes: codes for bad device tree blobs */
52 #define FDT_ERR_TRUNCATED	8
53 	/* FDT_ERR_TRUNCATED: FDT or a sub-block is improperly
54 	 * terminated (overflows, goes outside allowed bounds, or
55 	 * isn't properly terminated).  */
56 #define FDT_ERR_BADMAGIC	9
57 	/* FDT_ERR_BADMAGIC: Given "device tree" appears not to be a
58 	 * device tree at all - it is missing the flattened device
59 	 * tree magic number. */
60 #define FDT_ERR_BADVERSION	10
61 	/* FDT_ERR_BADVERSION: Given device tree has a version which
62 	 * can't be handled by the requested operation.  For
63 	 * read-write functions, this may mean that fdt_open_into() is
64 	 * required to convert the tree to the expected version. */
65 #define FDT_ERR_BADSTRUCTURE	11
66 	/* FDT_ERR_BADSTRUCTURE: Given device tree has a corrupt
67 	 * structure block or other serious error (e.g. misnested
68 	 * nodes, or subnodes preceding properties). */
69 #define FDT_ERR_BADLAYOUT	12
70 	/* FDT_ERR_BADLAYOUT: For read-write functions, the given
71 	 * device tree has it's sub-blocks in an order that the
72 	 * function can't handle (memory reserve map, then structure,
73 	 * then strings).  Use fdt_open_into() to reorganize the tree
74 	 * into a form suitable for the read-write operations. */
75 
76 /* "Can't happen" error indicating a bug in libfdt */
77 #define FDT_ERR_INTERNAL	13
78 	/* FDT_ERR_INTERNAL: libfdt has failed an internal assertion.
79 	 * Should never be returned, if it is, it indicates a bug in
80 	 * libfdt itself. */
81 
82 /* Errors in device tree content */
83 #define FDT_ERR_BADNCELLS	14
84 	/* FDT_ERR_BADNCELLS: Device tree has a #address-cells, #size-cells
85 	 * or similar property with a bad format or value */
86 
87 #define FDT_ERR_BADVALUE	15
88 	/* FDT_ERR_BADVALUE: Device tree has a property with an unexpected
89 	 * value. For example: a property expected to contain a string list
90 	 * is not NUL-terminated within the length of its value. */
91 
92 #define FDT_ERR_BADOVERLAY	16
93 	/* FDT_ERR_BADOVERLAY: The device tree overlay, while
94 	 * correctly structured, cannot be applied due to some
95 	 * unexpected or missing value, property or node. */
96 
97 #define FDT_ERR_NOPHANDLES	17
98 	/* FDT_ERR_NOPHANDLES: The device tree doesn't have any
99 	 * phandle available anymore without causing an overflow */
100 
101 #define FDT_ERR_BADFLAGS	18
102 	/* FDT_ERR_BADFLAGS: The function was passed a flags field that
103 	 * contains invalid flags or an invalid combination of flags. */
104 
105 #define FDT_ERR_ALIGNMENT	19
106 	/* FDT_ERR_ALIGNMENT: The device tree base address is not 8-byte
107 	 * aligned. */
108 
109 #define FDT_ERR_MAX		19
110 
111 /* constants */
112 #define FDT_MAX_PHANDLE 0xfffffffe
113 	/* Valid values for phandles range from 1 to 2^32-2. */
114 
115 /**********************************************************************/
116 /* Low-level functions (you probably don't need these)                */
117 /**********************************************************************/
118 
119 #ifndef SWIG /* This function is not useful in Python */
120 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int checklen);
121 #endif
122 static inline void *fdt_offset_ptr_w(void *fdt, int offset, int checklen)
123 {
124 	return (void *)(uintptr_t)fdt_offset_ptr(fdt, offset, checklen);
125 }
126 
127 uint32_t fdt_next_tag(const void *fdt, int offset, int *nextoffset);
128 
129 /*
130  * External helpers to access words from a device tree blob. They're built
131  * to work even with unaligned pointers on platforms (such as ARMv5) that don't
132  * like unaligned loads and stores.
133  */
134 static inline uint16_t fdt16_ld(const fdt16_t *p)
135 {
136 	const uint8_t *bp = (const uint8_t *)p;
137 
138 	return ((uint16_t)bp[0] << 8) | bp[1];
139 }
140 
141 static inline uint32_t fdt32_ld(const fdt32_t *p)
142 {
143 	const uint8_t *bp = (const uint8_t *)p;
144 
145 	return ((uint32_t)bp[0] << 24)
146 		| ((uint32_t)bp[1] << 16)
147 		| ((uint32_t)bp[2] << 8)
148 		| bp[3];
149 }
150 
151 static inline void fdt32_st(void *property, uint32_t value)
152 {
153 	uint8_t *bp = (uint8_t *)property;
154 
155 	bp[0] = value >> 24;
156 	bp[1] = (value >> 16) & 0xff;
157 	bp[2] = (value >> 8) & 0xff;
158 	bp[3] = value & 0xff;
159 }
160 
161 static inline uint64_t fdt64_ld(const fdt64_t *p)
162 {
163 	const uint8_t *bp = (const uint8_t *)p;
164 
165 	return ((uint64_t)bp[0] << 56)
166 		| ((uint64_t)bp[1] << 48)
167 		| ((uint64_t)bp[2] << 40)
168 		| ((uint64_t)bp[3] << 32)
169 		| ((uint64_t)bp[4] << 24)
170 		| ((uint64_t)bp[5] << 16)
171 		| ((uint64_t)bp[6] << 8)
172 		| bp[7];
173 }
174 
175 static inline void fdt64_st(void *property, uint64_t value)
176 {
177 	uint8_t *bp = (uint8_t *)property;
178 
179 	bp[0] = value >> 56;
180 	bp[1] = (value >> 48) & 0xff;
181 	bp[2] = (value >> 40) & 0xff;
182 	bp[3] = (value >> 32) & 0xff;
183 	bp[4] = (value >> 24) & 0xff;
184 	bp[5] = (value >> 16) & 0xff;
185 	bp[6] = (value >> 8) & 0xff;
186 	bp[7] = value & 0xff;
187 }
188 
189 /**********************************************************************/
190 /* Traversal functions                                                */
191 /**********************************************************************/
192 
193 int fdt_next_node(const void *fdt, int offset, int *depth);
194 
195 /**
196  * fdt_first_subnode() - get offset of first direct subnode
197  * @fdt:	FDT blob
198  * @offset:	Offset of node to check
199  *
200  * Return: offset of first subnode, or -FDT_ERR_NOTFOUND if there is none
201  */
202 int fdt_first_subnode(const void *fdt, int offset);
203 
204 /**
205  * fdt_next_subnode() - get offset of next direct subnode
206  * @fdt:	FDT blob
207  * @offset:	Offset of previous subnode
208  *
209  * After first calling fdt_first_subnode(), call this function repeatedly to
210  * get direct subnodes of a parent node.
211  *
212  * Return: offset of next subnode, or -FDT_ERR_NOTFOUND if there are no more
213  *         subnodes
214  */
215 int fdt_next_subnode(const void *fdt, int offset);
216 
217 /**
218  * fdt_for_each_subnode - iterate over all subnodes of a parent
219  *
220  * @node:	child node (int, lvalue)
221  * @fdt:	FDT blob (const void *)
222  * @parent:	parent node (int)
223  *
224  * This is actually a wrapper around a for loop and would be used like so:
225  *
226  *	fdt_for_each_subnode(node, fdt, parent) {
227  *		Use node
228  *		...
229  *	}
230  *
231  *	if ((node < 0) && (node != -FDT_ERR_NOTFOUND)) {
232  *		Error handling
233  *	}
234  *
235  * Note that this is implemented as a macro and @node is used as
236  * iterator in the loop. The parent variable be constant or even a
237  * literal.
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  * Return: size of DTB header in bytes
283  */
284 size_t fdt_header_size(const void *fdt);
285 
286 /**
287  * fdt_header_size_ - internal function to get header size from a version number
288  * @version: devicetree version number
289  *
290  * Return: size of DTB header in bytes
291  */
292 size_t fdt_header_size_(uint32_t version);
293 
294 /**
295  * fdt_check_header - sanity check a device tree header
296  * @fdt: pointer to data which might be a flattened device tree
297  *
298  * fdt_check_header() checks that the given buffer contains what
299  * appears to be a flattened device tree, and that the header contains
300  * valid information (to the extent that can be determined from the
301  * header alone).
302  *
303  * returns:
304  *     0, if the buffer appears to contain a valid device tree
305  *     -FDT_ERR_BADMAGIC,
306  *     -FDT_ERR_BADVERSION,
307  *     -FDT_ERR_BADSTATE,
308  *     -FDT_ERR_TRUNCATED, standard meanings, as above
309  */
310 int fdt_check_header(const void *fdt);
311 
312 /**
313  * fdt_move - move a device tree around in memory
314  * @fdt: pointer to the device tree to move
315  * @buf: pointer to memory where the device is to be moved
316  * @bufsize: size of the memory space at buf
317  *
318  * fdt_move() relocates, if possible, the device tree blob located at
319  * fdt to the buffer at buf of size bufsize.  The buffer may overlap
320  * with the existing device tree blob at fdt.  Therefore,
321  *     fdt_move(fdt, fdt, fdt_totalsize(fdt))
322  * should always succeed.
323  *
324  * returns:
325  *     0, on success
326  *     -FDT_ERR_NOSPACE, bufsize is insufficient to contain the device tree
327  *     -FDT_ERR_BADMAGIC,
328  *     -FDT_ERR_BADVERSION,
329  *     -FDT_ERR_BADSTATE, standard meanings
330  */
331 int fdt_move(const void *fdt, void *buf, int bufsize);
332 
333 /**********************************************************************/
334 /* Read-only functions                                                */
335 /**********************************************************************/
336 
337 int fdt_check_full(const void *fdt, size_t bufsize);
338 
339 /**
340  * fdt_get_string - retrieve a string from the strings block of a device tree
341  * @fdt: pointer to the device tree blob
342  * @stroffset: offset of the string within the strings block (native endian)
343  * @lenp: optional pointer to return the string's length
344  *
345  * fdt_get_string() retrieves a pointer to a single string from the
346  * strings block of the device tree blob at fdt, and optionally also
347  * returns the string's length in *lenp.
348  *
349  * returns:
350  *     a pointer to the string, on success
351  *     NULL, if stroffset is out of bounds, or doesn't point to a valid string
352  */
353 const char *fdt_get_string(const void *fdt, int stroffset, int *lenp);
354 
355 /**
356  * fdt_string - retrieve a string from the strings block of a device tree
357  * @fdt: pointer to the device tree blob
358  * @stroffset: offset of the string within the strings block (native endian)
359  *
360  * fdt_string() retrieves a pointer to a single string from the
361  * strings block of the device tree blob at fdt.
362  *
363  * returns:
364  *     a pointer to the string, on success
365  *     NULL, if stroffset is out of bounds, or doesn't point to a valid string
366  */
367 const char *fdt_string(const void *fdt, int stroffset);
368 
369 /**
370  * fdt_find_max_phandle - find and return the highest phandle in a tree
371  * @fdt: pointer to the device tree blob
372  * @phandle: return location for the highest phandle value found in the tree
373  *
374  * fdt_find_max_phandle() finds the highest phandle value in the given device
375  * tree. The value returned in @phandle is only valid if the function returns
376  * success.
377  *
378  * returns:
379  *     0 on success or a negative error code on failure
380  */
381 int fdt_find_max_phandle(const void *fdt, uint32_t *phandle);
382 
383 /**
384  * fdt_get_max_phandle - retrieves the highest phandle in a tree
385  * @fdt: pointer to the device tree blob
386  *
387  * fdt_get_max_phandle retrieves the highest phandle in the given
388  * device tree. This will ignore badly formatted phandles, or phandles
389  * with a value of 0 or -1.
390  *
391  * This function is deprecated in favour of fdt_find_max_phandle().
392  *
393  * returns:
394  *      the highest phandle on success
395  *      0, if no phandle was found in the device tree
396  *      -1, if an error occurred
397  */
398 static inline uint32_t fdt_get_max_phandle(const void *fdt)
399 {
400 	uint32_t phandle;
401 	int err;
402 
403 	err = fdt_find_max_phandle(fdt, &phandle);
404 	if (err < 0)
405 		return (uint32_t)-1;
406 
407 	return phandle;
408 }
409 
410 /**
411  * fdt_generate_phandle - return a new, unused phandle for a device tree blob
412  * @fdt: pointer to the device tree blob
413  * @phandle: return location for the new phandle
414  *
415  * Walks the device tree blob and looks for the highest phandle value. On
416  * success, the new, unused phandle value (one higher than the previously
417  * highest phandle value in the device tree blob) will be returned in the
418  * @phandle parameter.
419  *
420  * Return: 0 on success or a negative error-code on failure
421  */
422 int fdt_generate_phandle(const void *fdt, uint32_t *phandle);
423 
424 /**
425  * fdt_num_mem_rsv - retrieve the number of memory reserve map entries
426  * @fdt: pointer to the device tree blob
427  *
428  * Returns the number of entries in the device tree blob's memory
429  * reservation map.  This does not include the terminating 0,0 entry
430  * or any other (0,0) entries reserved for expansion.
431  *
432  * returns:
433  *     the number of entries
434  */
435 int fdt_num_mem_rsv(const void *fdt);
436 
437 /**
438  * fdt_get_mem_rsv - retrieve one memory reserve map entry
439  * @fdt: pointer to the device tree blob
440  * @n: index of reserve map entry
441  * @address: pointer to 64-bit variable to hold the start address
442  * @size: pointer to 64-bit variable to hold the size of the entry
443  *
444  * On success, @address and @size will contain the address and size of
445  * the n-th reserve map entry from the device tree blob, in
446  * native-endian format.
447  *
448  * returns:
449  *     0, on success
450  *     -FDT_ERR_BADMAGIC,
451  *     -FDT_ERR_BADVERSION,
452  *     -FDT_ERR_BADSTATE, standard meanings
453  */
454 int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size);
455 
456 /**
457  * fdt_subnode_offset_namelen - find a subnode based on substring
458  * @fdt: pointer to the device tree blob
459  * @parentoffset: structure block offset of a node
460  * @name: name of the subnode to locate
461  * @namelen: number of characters of name to consider
462  *
463  * Identical to fdt_subnode_offset(), but only examine the first
464  * namelen characters of name for matching the subnode name.  This is
465  * useful for finding subnodes based on a portion of a larger string,
466  * such as a full path.
467  *
468  * Return: offset of the subnode or -FDT_ERR_NOTFOUND if name not found.
469  */
470 #ifndef SWIG /* Not available in Python */
471 int fdt_subnode_offset_namelen(const void *fdt, int parentoffset,
472 			       const char *name, int namelen);
473 #endif
474 /**
475  * fdt_subnode_offset - find a subnode of a given node
476  * @fdt: pointer to the device tree blob
477  * @parentoffset: structure block offset of a node
478  * @name: name of the subnode to locate
479  *
480  * fdt_subnode_offset() finds a subnode of the node at structure block
481  * offset parentoffset with the given name.  name may include a unit
482  * address, in which case fdt_subnode_offset() will find the subnode
483  * with that unit address, or the unit address may be omitted, in
484  * which case fdt_subnode_offset() will find an arbitrary subnode
485  * whose name excluding unit address matches the given name.
486  *
487  * returns:
488  *	structure block offset of the requested subnode (>=0), on success
489  *	-FDT_ERR_NOTFOUND, if the requested subnode does not exist
490  *	-FDT_ERR_BADOFFSET, if parentoffset did not point to an FDT_BEGIN_NODE
491  *		tag
492  *	-FDT_ERR_BADMAGIC,
493  *	-FDT_ERR_BADVERSION,
494  *	-FDT_ERR_BADSTATE,
495  *	-FDT_ERR_BADSTRUCTURE,
496  *	-FDT_ERR_TRUNCATED, standard meanings.
497  */
498 int fdt_subnode_offset(const void *fdt, int parentoffset, const char *name);
499 
500 /**
501  * fdt_path_offset_namelen - find a tree node by its full path
502  * @fdt: pointer to the device tree blob
503  * @path: full path of the node to locate
504  * @namelen: number of characters of path to consider
505  *
506  * Identical to fdt_path_offset(), but only consider the first namelen
507  * characters of path as the path name.
508  *
509  * Return: offset of the node or negative libfdt error value otherwise
510  */
511 #ifndef SWIG /* Not available in Python */
512 int fdt_path_offset_namelen(const void *fdt, const char *path, int namelen);
513 #endif
514 
515 /**
516  * fdt_path_offset - find a tree node by its full path
517  * @fdt: pointer to the device tree blob
518  * @path: full path of the node to locate
519  *
520  * fdt_path_offset() finds a node of a given path in the device tree.
521  * Each path component may omit the unit address portion, but the
522  * results of this are undefined if any such path component is
523  * ambiguous (that is if there are multiple nodes at the relevant
524  * level matching the given component, differentiated only by unit
525  * address).
526  *
527  * returns:
528  *	structure block offset of the node with the requested path (>=0), on
529  *		success
530  *	-FDT_ERR_BADPATH, given path does not begin with '/' or is invalid
531  *	-FDT_ERR_NOTFOUND, if the requested node does not exist
532  *      -FDT_ERR_BADMAGIC,
533  *	-FDT_ERR_BADVERSION,
534  *	-FDT_ERR_BADSTATE,
535  *	-FDT_ERR_BADSTRUCTURE,
536  *	-FDT_ERR_TRUNCATED, standard meanings.
537  */
538 int fdt_path_offset(const void *fdt, const char *path);
539 
540 /**
541  * fdt_get_name - retrieve the name of a given node
542  * @fdt: pointer to the device tree blob
543  * @nodeoffset: structure block offset of the starting node
544  * @lenp: pointer to an integer variable (will be overwritten) or NULL
545  *
546  * fdt_get_name() retrieves the name (including unit address) of the
547  * device tree node at structure block offset nodeoffset.  If lenp is
548  * non-NULL, the length of this name is also returned, in the integer
549  * pointed to by lenp.
550  *
551  * returns:
552  *	pointer to the node's name, on success
553  *		If lenp is non-NULL, *lenp contains the length of that name
554  *			(>=0)
555  *	NULL, on error
556  *		if lenp is non-NULL *lenp contains an error code (<0):
557  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
558  *			tag
559  *		-FDT_ERR_BADMAGIC,
560  *		-FDT_ERR_BADVERSION,
561  *		-FDT_ERR_BADSTATE, standard meanings
562  */
563 const char *fdt_get_name(const void *fdt, int nodeoffset, int *lenp);
564 
565 /**
566  * fdt_first_property_offset - find the offset of a node's first property
567  * @fdt: pointer to the device tree blob
568  * @nodeoffset: structure block offset of a node
569  *
570  * fdt_first_property_offset() finds the first property of the node at
571  * the given structure block offset.
572  *
573  * returns:
574  *	structure block offset of the property (>=0), on success
575  *	-FDT_ERR_NOTFOUND, if the requested node has no properties
576  *	-FDT_ERR_BADOFFSET, if nodeoffset did not point to an FDT_BEGIN_NODE tag
577  *      -FDT_ERR_BADMAGIC,
578  *	-FDT_ERR_BADVERSION,
579  *	-FDT_ERR_BADSTATE,
580  *	-FDT_ERR_BADSTRUCTURE,
581  *	-FDT_ERR_TRUNCATED, standard meanings.
582  */
583 int fdt_first_property_offset(const void *fdt, int nodeoffset);
584 
585 /**
586  * fdt_next_property_offset - step through a node's properties
587  * @fdt: pointer to the device tree blob
588  * @offset: structure block offset of a property
589  *
590  * fdt_next_property_offset() finds the property immediately after the
591  * one at the given structure block offset.  This will be a property
592  * of the same node as the given property.
593  *
594  * returns:
595  *	structure block offset of the next property (>=0), on success
596  *	-FDT_ERR_NOTFOUND, if the given property is the last in its node
597  *	-FDT_ERR_BADOFFSET, if nodeoffset did not point to an FDT_PROP tag
598  *      -FDT_ERR_BADMAGIC,
599  *	-FDT_ERR_BADVERSION,
600  *	-FDT_ERR_BADSTATE,
601  *	-FDT_ERR_BADSTRUCTURE,
602  *	-FDT_ERR_TRUNCATED, standard meanings.
603  */
604 int fdt_next_property_offset(const void *fdt, int offset);
605 
606 /**
607  * fdt_for_each_property_offset - iterate over all properties of a node
608  *
609  * @property:	property offset (int, lvalue)
610  * @fdt:	FDT blob (const void *)
611  * @node:	node offset (int)
612  *
613  * This is actually a wrapper around a for loop and would be used like so:
614  *
615  *	fdt_for_each_property_offset(property, fdt, node) {
616  *		Use property
617  *		...
618  *	}
619  *
620  *	if ((property < 0) && (property != -FDT_ERR_NOTFOUND)) {
621  *		Error handling
622  *	}
623  *
624  * Note that this is implemented as a macro and property is used as
625  * iterator in the loop. The node variable can be constant or even a
626  * literal.
627  */
628 #define fdt_for_each_property_offset(property, fdt, node)	\
629 	for (property = fdt_first_property_offset(fdt, node);	\
630 	     property >= 0;					\
631 	     property = fdt_next_property_offset(fdt, property))
632 
633 /**
634  * fdt_get_property_by_offset - retrieve the property at a given offset
635  * @fdt: pointer to the device tree blob
636  * @offset: offset of the property to retrieve
637  * @lenp: pointer to an integer variable (will be overwritten) or NULL
638  *
639  * fdt_get_property_by_offset() retrieves a pointer to the
640  * fdt_property structure within the device tree blob at the given
641  * offset.  If lenp is non-NULL, the length of the property value is
642  * also returned, in the integer pointed to by lenp.
643  *
644  * Note that this code only works on device tree versions >= 16. fdt_getprop()
645  * works on all versions.
646  *
647  * returns:
648  *	pointer to the structure representing the property
649  *		if lenp is non-NULL, *lenp contains the length of the property
650  *		value (>=0)
651  *	NULL, on error
652  *		if lenp is non-NULL, *lenp contains an error code (<0):
653  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_PROP tag
654  *		-FDT_ERR_BADMAGIC,
655  *		-FDT_ERR_BADVERSION,
656  *		-FDT_ERR_BADSTATE,
657  *		-FDT_ERR_BADSTRUCTURE,
658  *		-FDT_ERR_TRUNCATED, standard meanings
659  */
660 const struct fdt_property *fdt_get_property_by_offset(const void *fdt,
661 						      int offset,
662 						      int *lenp);
663 static inline struct fdt_property *fdt_get_property_by_offset_w(void *fdt,
664 								int offset,
665 								int *lenp)
666 {
667 	return (struct fdt_property *)(uintptr_t)
668 		fdt_get_property_by_offset(fdt, offset, lenp);
669 }
670 
671 /**
672  * fdt_get_property_namelen - find a property based on substring
673  * @fdt: pointer to the device tree blob
674  * @nodeoffset: offset of the node whose property to find
675  * @name: name of the property to find
676  * @namelen: number of characters of name to consider
677  * @lenp: pointer to an integer variable (will be overwritten) or NULL
678  *
679  * Identical to fdt_get_property(), but only examine the first namelen
680  * characters of name for matching the property name.
681  *
682  * Return: pointer to the structure representing the property, or NULL
683  *         if not found
684  */
685 #ifndef SWIG /* Not available in Python */
686 const struct fdt_property *fdt_get_property_namelen(const void *fdt,
687 						    int nodeoffset,
688 						    const char *name,
689 						    int namelen, int *lenp);
690 #endif
691 
692 /**
693  * fdt_get_property - find a given property in a given node
694  * @fdt: pointer to the device tree blob
695  * @nodeoffset: offset of the node whose property to find
696  * @name: name of the property to find
697  * @lenp: pointer to an integer variable (will be overwritten) or NULL
698  *
699  * fdt_get_property() retrieves a pointer to the fdt_property
700  * structure within the device tree blob corresponding to the property
701  * named 'name' of the node at offset nodeoffset.  If lenp is
702  * non-NULL, the length of the property value is also returned, in the
703  * integer pointed to by lenp.
704  *
705  * returns:
706  *	pointer to the structure representing the property
707  *		if lenp is non-NULL, *lenp contains the length of the property
708  *		value (>=0)
709  *	NULL, on error
710  *		if lenp is non-NULL, *lenp contains an error code (<0):
711  *		-FDT_ERR_NOTFOUND, node does not have named property
712  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
713  *			tag
714  *		-FDT_ERR_BADMAGIC,
715  *		-FDT_ERR_BADVERSION,
716  *		-FDT_ERR_BADSTATE,
717  *		-FDT_ERR_BADSTRUCTURE,
718  *		-FDT_ERR_TRUNCATED, standard meanings
719  */
720 const struct fdt_property *fdt_get_property(const void *fdt, int nodeoffset,
721 					    const char *name, int *lenp);
722 static inline struct fdt_property *fdt_get_property_w(void *fdt, int nodeoffset,
723 						      const char *name,
724 						      int *lenp)
725 {
726 	return (struct fdt_property *)(uintptr_t)
727 		fdt_get_property(fdt, nodeoffset, name, lenp);
728 }
729 
730 /**
731  * fdt_getprop_by_offset - retrieve the value of a property at a given offset
732  * @fdt: pointer to the device tree blob
733  * @offset: offset of the property to read
734  * @namep: pointer to a string variable (will be overwritten) or NULL
735  * @lenp: pointer to an integer variable (will be overwritten) or NULL
736  *
737  * fdt_getprop_by_offset() retrieves a pointer to the value of the
738  * property at structure block offset 'offset' (this will be a pointer
739  * to within the device blob itself, not a copy of the value).  If
740  * lenp is non-NULL, the length of the property value is also
741  * returned, in the integer pointed to by lenp.  If namep is non-NULL,
742  * the property's namne will also be returned in the char * pointed to
743  * by namep (this will be a pointer to within the device tree's string
744  * block, not a new copy of the name).
745  *
746  * returns:
747  *	pointer to the property's value
748  *		if lenp is non-NULL, *lenp contains the length of the property
749  *		value (>=0)
750  *		if namep is non-NULL *namep contiains a pointer to the property
751  *		name.
752  *	NULL, on error
753  *		if lenp is non-NULL, *lenp contains an error code (<0):
754  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_PROP tag
755  *		-FDT_ERR_BADMAGIC,
756  *		-FDT_ERR_BADVERSION,
757  *		-FDT_ERR_BADSTATE,
758  *		-FDT_ERR_BADSTRUCTURE,
759  *		-FDT_ERR_TRUNCATED, standard meanings
760  */
761 #ifndef SWIG /* This function is not useful in Python */
762 const void *fdt_getprop_by_offset(const void *fdt, int offset,
763 				  const char **namep, int *lenp);
764 #endif
765 
766 /**
767  * fdt_getprop_namelen - get property value based on substring
768  * @fdt: pointer to the device tree blob
769  * @nodeoffset: offset of the node whose property to find
770  * @name: name of the property to find
771  * @namelen: number of characters of name to consider
772  * @lenp: pointer to an integer variable (will be overwritten) or NULL
773  *
774  * Identical to fdt_getprop(), but only examine the first namelen
775  * characters of name for matching the property name.
776  *
777  * Return: pointer to the property's value or NULL on error
778  */
779 #ifndef SWIG /* Not available in Python */
780 const void *fdt_getprop_namelen(const void *fdt, int nodeoffset,
781 				const char *name, int namelen, int *lenp);
782 static inline void *fdt_getprop_namelen_w(void *fdt, int nodeoffset,
783 					  const char *name, int namelen,
784 					  int *lenp)
785 {
786 	return (void *)(uintptr_t)fdt_getprop_namelen(fdt, nodeoffset, name,
787 						      namelen, lenp);
788 }
789 #endif
790 
791 /**
792  * fdt_getprop - retrieve the value of a given property
793  * @fdt: pointer to the device tree blob
794  * @nodeoffset: offset of the node whose property to find
795  * @name: name of the property to find
796  * @lenp: pointer to an integer variable (will be overwritten) or NULL
797  *
798  * fdt_getprop() retrieves a pointer to the value of the property
799  * named @name of the node at offset @nodeoffset (this will be a
800  * pointer to within the device blob itself, not a copy of the value).
801  * If @lenp is non-NULL, the length of the property value is also
802  * returned, in the integer pointed to by @lenp.
803  *
804  * returns:
805  *	pointer to the property's value
806  *		if lenp is non-NULL, *lenp contains the length of the property
807  *		value (>=0)
808  *	NULL, on error
809  *		if lenp is non-NULL, *lenp contains an error code (<0):
810  *		-FDT_ERR_NOTFOUND, node does not have named property
811  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
812  *			tag
813  *		-FDT_ERR_BADMAGIC,
814  *		-FDT_ERR_BADVERSION,
815  *		-FDT_ERR_BADSTATE,
816  *		-FDT_ERR_BADSTRUCTURE,
817  *		-FDT_ERR_TRUNCATED, standard meanings
818  */
819 const void *fdt_getprop(const void *fdt, int nodeoffset,
820 			const char *name, int *lenp);
821 static inline void *fdt_getprop_w(void *fdt, int nodeoffset,
822 				  const char *name, int *lenp)
823 {
824 	return (void *)(uintptr_t)fdt_getprop(fdt, nodeoffset, name, lenp);
825 }
826 
827 /**
828  * fdt_get_phandle - retrieve the phandle of a given node
829  * @fdt: pointer to the device tree blob
830  * @nodeoffset: structure block offset of the node
831  *
832  * fdt_get_phandle() retrieves the phandle of the device tree node at
833  * structure block offset nodeoffset.
834  *
835  * returns:
836  *	the phandle of the node at nodeoffset, on success (!= 0, != -1)
837  *	0, if the node has no phandle, or another error occurs
838  */
839 uint32_t fdt_get_phandle(const void *fdt, int nodeoffset);
840 
841 /**
842  * fdt_get_alias_namelen - get alias based on substring
843  * @fdt: pointer to the device tree blob
844  * @name: name of the alias th look up
845  * @namelen: number of characters of name to consider
846  *
847  * Identical to fdt_get_alias(), but only examine the first @namelen
848  * characters of @name for matching the alias name.
849  *
850  * Return: a pointer to the expansion of the alias named @name, if it exists,
851  *	   NULL otherwise
852  */
853 #ifndef SWIG /* Not available in Python */
854 const char *fdt_get_alias_namelen(const void *fdt,
855 				  const char *name, int namelen);
856 #endif
857 
858 /**
859  * fdt_get_alias - retrieve the path referenced by a given alias
860  * @fdt: pointer to the device tree blob
861  * @name: name of the alias th look up
862  *
863  * fdt_get_alias() retrieves the value of a given alias.  That is, the
864  * value of the property named @name in the node /aliases.
865  *
866  * returns:
867  *	a pointer to the expansion of the alias named 'name', if it exists
868  *	NULL, if the given alias or the /aliases node does not exist
869  */
870 const char *fdt_get_alias(const void *fdt, const char *name);
871 
872 /**
873  * fdt_get_path - determine the full path of a node
874  * @fdt: pointer to the device tree blob
875  * @nodeoffset: offset of the node whose path to find
876  * @buf: character buffer to contain the returned path (will be overwritten)
877  * @buflen: size of the character buffer at buf
878  *
879  * fdt_get_path() computes the full path of the node at offset
880  * nodeoffset, and records that path in the buffer at buf.
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  *	0, on success
887  *		buf contains the absolute path of the node at
888  *		nodeoffset, as a NUL-terminated string.
889  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
890  *	-FDT_ERR_NOSPACE, the path of the given node is longer than (bufsize-1)
891  *		characters and will not fit in the given buffer.
892  *	-FDT_ERR_BADMAGIC,
893  *	-FDT_ERR_BADVERSION,
894  *	-FDT_ERR_BADSTATE,
895  *	-FDT_ERR_BADSTRUCTURE, standard meanings
896  */
897 int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen);
898 
899 /**
900  * fdt_supernode_atdepth_offset - find a specific ancestor of a node
901  * @fdt: pointer to the device tree blob
902  * @nodeoffset: offset of the node whose parent to find
903  * @supernodedepth: depth of the ancestor to find
904  * @nodedepth: pointer to an integer variable (will be overwritten) or NULL
905  *
906  * fdt_supernode_atdepth_offset() finds an ancestor of the given node
907  * at a specific depth from the root (where the root itself has depth
908  * 0, its immediate subnodes depth 1 and so forth).  So
909  *	fdt_supernode_atdepth_offset(fdt, nodeoffset, 0, NULL);
910  * will always return 0, the offset of the root node.  If the node at
911  * nodeoffset has depth D, then:
912  *	fdt_supernode_atdepth_offset(fdt, nodeoffset, D, NULL);
913  * will return nodeoffset itself.
914  *
915  * NOTE: This function is expensive, as it must scan the device tree
916  * structure from the start to nodeoffset.
917  *
918  * returns:
919  *	structure block offset of the node at node offset's ancestor
920  *		of depth supernodedepth (>=0), on success
921  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
922  *	-FDT_ERR_NOTFOUND, supernodedepth was greater than the depth of
923  *		nodeoffset
924  *	-FDT_ERR_BADMAGIC,
925  *	-FDT_ERR_BADVERSION,
926  *	-FDT_ERR_BADSTATE,
927  *	-FDT_ERR_BADSTRUCTURE, standard meanings
928  */
929 int fdt_supernode_atdepth_offset(const void *fdt, int nodeoffset,
930 				 int supernodedepth, int *nodedepth);
931 
932 /**
933  * fdt_node_depth - find the depth of a given node
934  * @fdt: pointer to the device tree blob
935  * @nodeoffset: offset of the node whose parent to find
936  *
937  * fdt_node_depth() finds the depth of a given node.  The root node
938  * has depth 0, its immediate subnodes depth 1 and so forth.
939  *
940  * NOTE: This function is expensive, as it must scan the device tree
941  * structure from the start to nodeoffset.
942  *
943  * returns:
944  *	depth of the node at nodeoffset (>=0), on success
945  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
946  *	-FDT_ERR_BADMAGIC,
947  *	-FDT_ERR_BADVERSION,
948  *	-FDT_ERR_BADSTATE,
949  *	-FDT_ERR_BADSTRUCTURE, standard meanings
950  */
951 int fdt_node_depth(const void *fdt, int nodeoffset);
952 
953 /**
954  * fdt_parent_offset - find the parent of a given node
955  * @fdt: pointer to the device tree blob
956  * @nodeoffset: offset of the node whose parent to find
957  *
958  * fdt_parent_offset() locates the parent node of a given node (that
959  * is, it finds the offset of the node which contains the node at
960  * nodeoffset as a subnode).
961  *
962  * NOTE: This function is expensive, as it must scan the device tree
963  * structure from the start to nodeoffset, *twice*.
964  *
965  * returns:
966  *	structure block offset of the parent of the node at nodeoffset
967  *		(>=0), on success
968  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
969  *	-FDT_ERR_BADMAGIC,
970  *	-FDT_ERR_BADVERSION,
971  *	-FDT_ERR_BADSTATE,
972  *	-FDT_ERR_BADSTRUCTURE, standard meanings
973  */
974 int fdt_parent_offset(const void *fdt, int nodeoffset);
975 
976 /**
977  * fdt_node_offset_by_prop_value - find nodes with a given property value
978  * @fdt: pointer to the device tree blob
979  * @startoffset: only find nodes after this offset
980  * @propname: property name to check
981  * @propval: property value to search for
982  * @proplen: length of the value in propval
983  *
984  * fdt_node_offset_by_prop_value() returns the offset of the first
985  * node after startoffset, which has a property named propname whose
986  * value is of length proplen and has value equal to propval; or if
987  * startoffset is -1, the very first such node in the tree.
988  *
989  * To iterate through all nodes matching the criterion, the following
990  * idiom can be used:
991  *	offset = fdt_node_offset_by_prop_value(fdt, -1, propname,
992  *					       propval, proplen);
993  *	while (offset != -FDT_ERR_NOTFOUND) {
994  *		// other code here
995  *		offset = fdt_node_offset_by_prop_value(fdt, offset, propname,
996  *						       propval, proplen);
997  *	}
998  *
999  * Note the -1 in the first call to the function, if 0 is used here
1000  * instead, the function will never locate the root node, even if it
1001  * matches the criterion.
1002  *
1003  * returns:
1004  *	structure block offset of the located node (>= 0, >startoffset),
1005  *		 on success
1006  *	-FDT_ERR_NOTFOUND, no node matching the criterion exists in the
1007  *		tree after startoffset
1008  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
1009  *	-FDT_ERR_BADMAGIC,
1010  *	-FDT_ERR_BADVERSION,
1011  *	-FDT_ERR_BADSTATE,
1012  *	-FDT_ERR_BADSTRUCTURE, standard meanings
1013  */
1014 int fdt_node_offset_by_prop_value(const void *fdt, int startoffset,
1015 				  const char *propname,
1016 				  const void *propval, int proplen);
1017 
1018 /**
1019  * fdt_node_offset_by_phandle - find the node with a given phandle
1020  * @fdt: pointer to the device tree blob
1021  * @phandle: phandle value
1022  *
1023  * fdt_node_offset_by_phandle() returns the offset of the node
1024  * which has the given phandle value.  If there is more than one node
1025  * in the tree with the given phandle (an invalid tree), results are
1026  * undefined.
1027  *
1028  * returns:
1029  *	structure block offset of the located node (>= 0), on success
1030  *	-FDT_ERR_NOTFOUND, no node with that phandle exists
1031  *	-FDT_ERR_BADPHANDLE, given phandle value was invalid (0 or -1)
1032  *	-FDT_ERR_BADMAGIC,
1033  *	-FDT_ERR_BADVERSION,
1034  *	-FDT_ERR_BADSTATE,
1035  *	-FDT_ERR_BADSTRUCTURE, standard meanings
1036  */
1037 int fdt_node_offset_by_phandle(const void *fdt, uint32_t phandle);
1038 
1039 /**
1040  * fdt_node_check_compatible - check a node's compatible property
1041  * @fdt: pointer to the device tree blob
1042  * @nodeoffset: offset of a tree node
1043  * @compatible: string to match against
1044  *
1045  * fdt_node_check_compatible() returns 0 if the given node contains a
1046  * @compatible property with the given string as one of its elements,
1047  * it returns non-zero otherwise, or on error.
1048  *
1049  * returns:
1050  *	0, if the node has a 'compatible' property listing the given string
1051  *	1, if the node has a 'compatible' property, but it does not list
1052  *		the given string
1053  *	-FDT_ERR_NOTFOUND, if the given node has no 'compatible' property
1054  *	-FDT_ERR_BADOFFSET, if nodeoffset does not refer to a BEGIN_NODE tag
1055  *	-FDT_ERR_BADMAGIC,
1056  *	-FDT_ERR_BADVERSION,
1057  *	-FDT_ERR_BADSTATE,
1058  *	-FDT_ERR_BADSTRUCTURE, standard meanings
1059  */
1060 int fdt_node_check_compatible(const void *fdt, int nodeoffset,
1061 			      const char *compatible);
1062 
1063 /**
1064  * fdt_node_offset_by_compatible - find nodes with a given 'compatible' value
1065  * @fdt: pointer to the device tree blob
1066  * @startoffset: only find nodes after this offset
1067  * @compatible: 'compatible' string to match against
1068  *
1069  * fdt_node_offset_by_compatible() returns the offset of the first
1070  * node after startoffset, which has a 'compatible' property which
1071  * lists the given compatible string; or if startoffset is -1, the
1072  * very first such node in the tree.
1073  *
1074  * To iterate through all nodes matching the criterion, the following
1075  * idiom can be used:
1076  *	offset = fdt_node_offset_by_compatible(fdt, -1, compatible);
1077  *	while (offset != -FDT_ERR_NOTFOUND) {
1078  *		// other code here
1079  *		offset = fdt_node_offset_by_compatible(fdt, offset, compatible);
1080  *	}
1081  *
1082  * Note the -1 in the first call to the function, if 0 is used here
1083  * instead, the function will never locate the root node, even if it
1084  * matches the criterion.
1085  *
1086  * returns:
1087  *	structure block offset of the located node (>= 0, >startoffset),
1088  *		 on success
1089  *	-FDT_ERR_NOTFOUND, no node matching the criterion exists in the
1090  *		tree after startoffset
1091  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
1092  *	-FDT_ERR_BADMAGIC,
1093  *	-FDT_ERR_BADVERSION,
1094  *	-FDT_ERR_BADSTATE,
1095  *	-FDT_ERR_BADSTRUCTURE, standard meanings
1096  */
1097 int fdt_node_offset_by_compatible(const void *fdt, int startoffset,
1098 				  const char *compatible);
1099 
1100 /**
1101  * fdt_stringlist_contains - check a string list property for a string
1102  * @strlist: Property containing a list of strings to check
1103  * @listlen: Length of property
1104  * @str: String to search for
1105  *
1106  * This is a utility function provided for convenience. The list contains
1107  * one or more strings, each terminated by \0, as is found in a device tree
1108  * "compatible" property.
1109  *
1110  * Return: 1 if the string is found in the list, 0 not found, or invalid list
1111  */
1112 int fdt_stringlist_contains(const char *strlist, int listlen, const char *str);
1113 
1114 /**
1115  * fdt_stringlist_count - count the number of strings in a string list
1116  * @fdt: pointer to the device tree blob
1117  * @nodeoffset: offset of a tree node
1118  * @property: name of the property containing the string list
1119  *
1120  * Return:
1121  *   the number of strings in the given property
1122  *   -FDT_ERR_BADVALUE if the property value is not NUL-terminated
1123  *   -FDT_ERR_NOTFOUND if the property does not exist
1124  */
1125 int fdt_stringlist_count(const void *fdt, int nodeoffset, const char *property);
1126 
1127 /**
1128  * fdt_stringlist_search - find a string in a string list and return its index
1129  * @fdt: pointer to the device tree blob
1130  * @nodeoffset: offset of a tree node
1131  * @property: name of the property containing the string list
1132  * @string: string to look up in the string list
1133  *
1134  * Note that it is possible for this function to succeed on property values
1135  * that are not NUL-terminated. That's because the function will stop after
1136  * finding the first occurrence of @string. This can for example happen with
1137  * small-valued cell properties, such as #address-cells, when searching for
1138  * the empty string.
1139  *
1140  * return:
1141  *   the index of the string in the list of strings
1142  *   -FDT_ERR_BADVALUE if the property value is not NUL-terminated
1143  *   -FDT_ERR_NOTFOUND if the property does not exist or does not contain
1144  *                     the given string
1145  */
1146 int fdt_stringlist_search(const void *fdt, int nodeoffset, const char *property,
1147 			  const char *string);
1148 
1149 /**
1150  * fdt_stringlist_get() - obtain the string at a given index in a string list
1151  * @fdt: pointer to the device tree blob
1152  * @nodeoffset: offset of a tree node
1153  * @property: name of the property containing the string list
1154  * @index: index of the string to return
1155  * @lenp: return location for the string length or an error code on failure
1156  *
1157  * Note that this will successfully extract strings from properties with
1158  * non-NUL-terminated values. For example on small-valued cell properties
1159  * this function will return the empty string.
1160  *
1161  * If non-NULL, the length of the string (on success) or a negative error-code
1162  * (on failure) will be stored in the integer pointer to by lenp.
1163  *
1164  * Return:
1165  *   A pointer to the string at the given index in the string list or NULL on
1166  *   failure. On success the length of the string will be stored in the memory
1167  *   location pointed to by the lenp parameter, if non-NULL. On failure one of
1168  *   the following negative error codes will be returned in the lenp parameter
1169  *   (if non-NULL):
1170  *     -FDT_ERR_BADVALUE if the property value is not NUL-terminated
1171  *     -FDT_ERR_NOTFOUND if the property does not exist
1172  */
1173 const char *fdt_stringlist_get(const void *fdt, int nodeoffset,
1174 			       const char *property, int index,
1175 			       int *lenp);
1176 
1177 /**********************************************************************/
1178 /* Read-only functions (addressing related)                           */
1179 /**********************************************************************/
1180 
1181 /**
1182  * FDT_MAX_NCELLS - maximum value for #address-cells and #size-cells
1183  *
1184  * This is the maximum value for #address-cells, #size-cells and
1185  * similar properties that will be processed by libfdt.  IEE1275
1186  * requires that OF implementations handle values up to 4.
1187  * Implementations may support larger values, but in practice higher
1188  * values aren't used.
1189  */
1190 #define FDT_MAX_NCELLS		4
1191 
1192 /**
1193  * fdt_address_cells - retrieve address size for a bus represented in the tree
1194  * @fdt: pointer to the device tree blob
1195  * @nodeoffset: offset of the node to find the address size for
1196  *
1197  * When the node has a valid #address-cells property, returns its value.
1198  *
1199  * returns:
1200  *	0 <= n < FDT_MAX_NCELLS, on success
1201  *      2, if the node has no #address-cells property
1202  *      -FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
1203  *		#address-cells property
1204  *	-FDT_ERR_BADMAGIC,
1205  *	-FDT_ERR_BADVERSION,
1206  *	-FDT_ERR_BADSTATE,
1207  *	-FDT_ERR_BADSTRUCTURE,
1208  *	-FDT_ERR_TRUNCATED, standard meanings
1209  */
1210 int fdt_address_cells(const void *fdt, int nodeoffset);
1211 
1212 /**
1213  * fdt_size_cells - retrieve address range size for a bus represented in the
1214  *                  tree
1215  * @fdt: pointer to the device tree blob
1216  * @nodeoffset: offset of the node to find the address range size for
1217  *
1218  * When the node has a valid #size-cells property, returns its value.
1219  *
1220  * returns:
1221  *	0 <= n < FDT_MAX_NCELLS, on success
1222  *      1, if the node has no #size-cells property
1223  *      -FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
1224  *		#size-cells property
1225  *	-FDT_ERR_BADMAGIC,
1226  *	-FDT_ERR_BADVERSION,
1227  *	-FDT_ERR_BADSTATE,
1228  *	-FDT_ERR_BADSTRUCTURE,
1229  *	-FDT_ERR_TRUNCATED, standard meanings
1230  */
1231 int fdt_size_cells(const void *fdt, int nodeoffset);
1232 
1233 
1234 /**********************************************************************/
1235 /* Write-in-place functions                                           */
1236 /**********************************************************************/
1237 
1238 /**
1239  * fdt_setprop_inplace_namelen_partial - change a property's value,
1240  *                                       but not its size
1241  * @fdt: pointer to the device tree blob
1242  * @nodeoffset: offset of the node whose property to change
1243  * @name: name of the property to change
1244  * @namelen: number of characters of name to consider
1245  * @idx: index of the property to change in the array
1246  * @val: pointer to data to replace the property value with
1247  * @len: length of the property value
1248  *
1249  * Identical to fdt_setprop_inplace(), but modifies the given property
1250  * starting from the given index, and using only the first characters
1251  * of the name. It is useful when you want to manipulate only one value of
1252  * an array and you have a string that doesn't end with \0.
1253  *
1254  * Return: 0 on success, negative libfdt error value otherwise
1255  */
1256 #ifndef SWIG /* Not available in Python */
1257 int fdt_setprop_inplace_namelen_partial(void *fdt, int nodeoffset,
1258 					const char *name, int namelen,
1259 					uint32_t idx, const void *val,
1260 					int len);
1261 #endif
1262 
1263 /**
1264  * fdt_setprop_inplace - change a property's value, but not its size
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: pointer to data to replace the property value with
1269  * @len: length of the property value
1270  *
1271  * fdt_setprop_inplace() replaces the value of a given property with
1272  * the data in val, of length len.  This function cannot change the
1273  * size of a property, and so will only work if len is equal to the
1274  * current length of the property.
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 len is not equal to the property's current length
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 #ifndef SWIG /* Not available in Python */
1292 int fdt_setprop_inplace(void *fdt, int nodeoffset, const char *name,
1293 			const void *val, int len);
1294 #endif
1295 
1296 /**
1297  * fdt_setprop_inplace_u32 - change the value of a 32-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: 32-bit integer value to replace the property with
1302  *
1303  * fdt_setprop_inplace_u32() replaces the value of a given property
1304  * with the 32-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  * 4.
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 4
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_u32(void *fdt, int nodeoffset,
1325 					  const char *name, uint32_t val)
1326 {
1327 	fdt32_t tmp = cpu_to_fdt32(val);
1328 	return fdt_setprop_inplace(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1329 }
1330 
1331 /**
1332  * fdt_setprop_inplace_u64 - change the value of a 64-bit integer property
1333  * @fdt: pointer to the device tree blob
1334  * @nodeoffset: offset of the node whose property to change
1335  * @name: name of the property to change
1336  * @val: 64-bit integer value to replace the property with
1337  *
1338  * fdt_setprop_inplace_u64() replaces the value of a given property
1339  * with the 64-bit integer value in val, converting val to big-endian
1340  * if necessary.  This function cannot change the size of a property,
1341  * and so will only work if the property already exists and has length
1342  * 8.
1343  *
1344  * This function will alter only the bytes in the blob which contain
1345  * the given property value, and will not alter or move any other part
1346  * of the tree.
1347  *
1348  * returns:
1349  *	0, on success
1350  *	-FDT_ERR_NOSPACE, if the property's length is not equal to 8
1351  *	-FDT_ERR_NOTFOUND, node does not have the named property
1352  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1353  *	-FDT_ERR_BADMAGIC,
1354  *	-FDT_ERR_BADVERSION,
1355  *	-FDT_ERR_BADSTATE,
1356  *	-FDT_ERR_BADSTRUCTURE,
1357  *	-FDT_ERR_TRUNCATED, standard meanings
1358  */
1359 static inline int fdt_setprop_inplace_u64(void *fdt, int nodeoffset,
1360 					  const char *name, uint64_t val)
1361 {
1362 	fdt64_t tmp = cpu_to_fdt64(val);
1363 	return fdt_setprop_inplace(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1364 }
1365 
1366 /**
1367  * fdt_setprop_inplace_cell - change the value of a single-cell property
1368  * @fdt: pointer to the device tree blob
1369  * @nodeoffset: offset of the node containing the property
1370  * @name: name of the property to change the value of
1371  * @val: new value of the 32-bit cell
1372  *
1373  * This is an alternative name for fdt_setprop_inplace_u32()
1374  * Return: 0 on success, negative libfdt error number otherwise.
1375  */
1376 static inline int fdt_setprop_inplace_cell(void *fdt, int nodeoffset,
1377 					   const char *name, uint32_t val)
1378 {
1379 	return fdt_setprop_inplace_u32(fdt, nodeoffset, name, val);
1380 }
1381 
1382 /**
1383  * fdt_nop_property - replace a property with nop tags
1384  * @fdt: pointer to the device tree blob
1385  * @nodeoffset: offset of the node whose property to nop
1386  * @name: name of the property to nop
1387  *
1388  * fdt_nop_property() will replace a given property's representation
1389  * in the blob with FDT_NOP tags, effectively removing it from the
1390  * tree.
1391  *
1392  * This function will alter only the bytes in the blob which contain
1393  * the property, and will not alter or move any other part of the
1394  * tree.
1395  *
1396  * returns:
1397  *	0, on success
1398  *	-FDT_ERR_NOTFOUND, node does not have the named property
1399  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1400  *	-FDT_ERR_BADMAGIC,
1401  *	-FDT_ERR_BADVERSION,
1402  *	-FDT_ERR_BADSTATE,
1403  *	-FDT_ERR_BADSTRUCTURE,
1404  *	-FDT_ERR_TRUNCATED, standard meanings
1405  */
1406 int fdt_nop_property(void *fdt, int nodeoffset, const char *name);
1407 
1408 /**
1409  * fdt_nop_node - replace a node (subtree) with nop tags
1410  * @fdt: pointer to the device tree blob
1411  * @nodeoffset: offset of the node to nop
1412  *
1413  * fdt_nop_node() will replace a given node's representation in the
1414  * blob, including all its subnodes, if any, with FDT_NOP tags,
1415  * effectively removing it from the tree.
1416  *
1417  * This function will alter only the bytes in the blob which contain
1418  * the node and its properties and subnodes, and will not alter or
1419  * move any other part of the tree.
1420  *
1421  * returns:
1422  *	0, on success
1423  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1424  *	-FDT_ERR_BADMAGIC,
1425  *	-FDT_ERR_BADVERSION,
1426  *	-FDT_ERR_BADSTATE,
1427  *	-FDT_ERR_BADSTRUCTURE,
1428  *	-FDT_ERR_TRUNCATED, standard meanings
1429  */
1430 int fdt_nop_node(void *fdt, int nodeoffset);
1431 
1432 /**********************************************************************/
1433 /* Sequential write functions                                         */
1434 /**********************************************************************/
1435 
1436 /* fdt_create_with_flags flags */
1437 #define FDT_CREATE_FLAG_NO_NAME_DEDUP 0x1
1438 	/* FDT_CREATE_FLAG_NO_NAME_DEDUP: Do not try to de-duplicate property
1439 	 * names in the fdt. This can result in faster creation times, but
1440 	 * a larger fdt. */
1441 
1442 #define FDT_CREATE_FLAGS_ALL	(FDT_CREATE_FLAG_NO_NAME_DEDUP)
1443 
1444 /**
1445  * fdt_create_with_flags - begin creation of a new fdt
1446  * @buf: pointer to memory allocated where fdt will be created
1447  * @bufsize: size of the memory space at fdt
1448  * @flags: a valid combination of FDT_CREATE_FLAG_ flags, or 0.
1449  *
1450  * fdt_create_with_flags() begins the process of creating a new fdt with
1451  * the sequential write interface.
1452  *
1453  * fdt creation process must end with fdt_finished() to produce a valid fdt.
1454  *
1455  * returns:
1456  *	0, on success
1457  *	-FDT_ERR_NOSPACE, bufsize is insufficient for a minimal fdt
1458  *	-FDT_ERR_BADFLAGS, flags is not valid
1459  */
1460 int fdt_create_with_flags(void *buf, int bufsize, uint32_t flags);
1461 
1462 /**
1463  * fdt_create - begin creation of a new fdt
1464  * @buf: pointer to memory allocated where fdt will be created
1465  * @bufsize: size of the memory space at fdt
1466  *
1467  * fdt_create() is equivalent to fdt_create_with_flags() with flags=0.
1468  *
1469  * returns:
1470  *	0, on success
1471  *	-FDT_ERR_NOSPACE, bufsize is insufficient for a minimal fdt
1472  */
1473 int fdt_create(void *buf, int bufsize);
1474 
1475 int fdt_resize(void *fdt, void *buf, int bufsize);
1476 int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size);
1477 int fdt_finish_reservemap(void *fdt);
1478 int fdt_begin_node(void *fdt, const char *name);
1479 int fdt_property(void *fdt, const char *name, const void *val, int len);
1480 static inline int fdt_property_u32(void *fdt, const char *name, uint32_t val)
1481 {
1482 	fdt32_t tmp = cpu_to_fdt32(val);
1483 	return fdt_property(fdt, name, &tmp, sizeof(tmp));
1484 }
1485 static inline int fdt_property_u64(void *fdt, const char *name, uint64_t val)
1486 {
1487 	fdt64_t tmp = cpu_to_fdt64(val);
1488 	return fdt_property(fdt, name, &tmp, sizeof(tmp));
1489 }
1490 
1491 #ifndef SWIG /* Not available in Python */
1492 static inline int fdt_property_cell(void *fdt, const char *name, uint32_t val)
1493 {
1494 	return fdt_property_u32(fdt, name, val);
1495 }
1496 #endif
1497 
1498 /**
1499  * fdt_property_placeholder - add a new property and return a ptr to its value
1500  *
1501  * @fdt: pointer to the device tree blob
1502  * @name: name of property to add
1503  * @len: length of property value in bytes
1504  * @valp: returns a pointer to where where the value should be placed
1505  *
1506  * returns:
1507  *	0, on success
1508  *	-FDT_ERR_BADMAGIC,
1509  *	-FDT_ERR_NOSPACE, standard meanings
1510  */
1511 int fdt_property_placeholder(void *fdt, const char *name, int len, void **valp);
1512 
1513 #define fdt_property_string(fdt, name, str) \
1514 	fdt_property(fdt, name, str, strlen(str)+1)
1515 int fdt_end_node(void *fdt);
1516 int fdt_finish(void *fdt);
1517 
1518 /**********************************************************************/
1519 /* Read-write functions                                               */
1520 /**********************************************************************/
1521 
1522 int fdt_create_empty_tree(void *buf, int bufsize);
1523 int fdt_open_into(const void *fdt, void *buf, int bufsize);
1524 int fdt_pack(void *fdt);
1525 
1526 /**
1527  * fdt_add_mem_rsv - add one memory reserve map entry
1528  * @fdt: pointer to the device tree blob
1529  * @address: 64-bit start address of the reserve map entry
1530  * @size: 64-bit size of the reserved region
1531  *
1532  * Adds a reserve map entry to the given blob reserving a region at
1533  * address address of length size.
1534  *
1535  * This function will insert data into the reserve map and will
1536  * therefore change the indexes of some entries in the table.
1537  *
1538  * returns:
1539  *	0, on success
1540  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1541  *		contain the new reservation entry
1542  *	-FDT_ERR_BADMAGIC,
1543  *	-FDT_ERR_BADVERSION,
1544  *	-FDT_ERR_BADSTATE,
1545  *	-FDT_ERR_BADSTRUCTURE,
1546  *	-FDT_ERR_BADLAYOUT,
1547  *	-FDT_ERR_TRUNCATED, standard meanings
1548  */
1549 int fdt_add_mem_rsv(void *fdt, uint64_t address, uint64_t size);
1550 
1551 /**
1552  * fdt_del_mem_rsv - remove a memory reserve map entry
1553  * @fdt: pointer to the device tree blob
1554  * @n: entry to remove
1555  *
1556  * fdt_del_mem_rsv() removes the n-th memory reserve map entry from
1557  * the blob.
1558  *
1559  * This function will delete data from the reservation table and will
1560  * therefore change the indexes of some entries in the table.
1561  *
1562  * returns:
1563  *	0, on success
1564  *	-FDT_ERR_NOTFOUND, there is no entry of the given index (i.e. there
1565  *		are less than n+1 reserve map entries)
1566  *	-FDT_ERR_BADMAGIC,
1567  *	-FDT_ERR_BADVERSION,
1568  *	-FDT_ERR_BADSTATE,
1569  *	-FDT_ERR_BADSTRUCTURE,
1570  *	-FDT_ERR_BADLAYOUT,
1571  *	-FDT_ERR_TRUNCATED, standard meanings
1572  */
1573 int fdt_del_mem_rsv(void *fdt, int n);
1574 
1575 /**
1576  * fdt_set_name - change the name of a given node
1577  * @fdt: pointer to the device tree blob
1578  * @nodeoffset: structure block offset of a node
1579  * @name: name to give the node
1580  *
1581  * fdt_set_name() replaces the name (including unit address, if any)
1582  * of the given node with the given string.  NOTE: this function can't
1583  * efficiently check if the new name is unique amongst the given
1584  * node's siblings; results are undefined if this function is invoked
1585  * with a name equal to one of the given node's siblings.
1586  *
1587  * This function may insert or delete data from the blob, and will
1588  * therefore change the offsets of some existing nodes.
1589  *
1590  * returns:
1591  *	0, on success
1592  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob
1593  *		to contain the new name
1594  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1595  *	-FDT_ERR_BADMAGIC,
1596  *	-FDT_ERR_BADVERSION,
1597  *	-FDT_ERR_BADSTATE, standard meanings
1598  */
1599 int fdt_set_name(void *fdt, int nodeoffset, const char *name);
1600 
1601 /**
1602  * fdt_setprop - create or change a property
1603  * @fdt: pointer to the device tree blob
1604  * @nodeoffset: offset of the node whose property to change
1605  * @name: name of the property to change
1606  * @val: pointer to data to set the property value to
1607  * @len: length of the property value
1608  *
1609  * fdt_setprop() sets the value of the named property in the given
1610  * node to the given value and length, creating the property if it
1611  * does not already exist.
1612  *
1613  * This function may insert or delete data from the blob, and will
1614  * therefore change the offsets of some existing nodes.
1615  *
1616  * returns:
1617  *	0, on success
1618  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1619  *		contain the new property value
1620  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1621  *	-FDT_ERR_BADLAYOUT,
1622  *	-FDT_ERR_BADMAGIC,
1623  *	-FDT_ERR_BADVERSION,
1624  *	-FDT_ERR_BADSTATE,
1625  *	-FDT_ERR_BADSTRUCTURE,
1626  *	-FDT_ERR_BADLAYOUT,
1627  *	-FDT_ERR_TRUNCATED, standard meanings
1628  */
1629 int fdt_setprop(void *fdt, int nodeoffset, const char *name,
1630 		const void *val, int len);
1631 
1632 /**
1633  * fdt_setprop_placeholder - allocate space for a property
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  * @len: length of the property value
1638  * @prop_data: return pointer to property data
1639  *
1640  * fdt_setprop_placeholer() allocates the named property in the given node.
1641  * If the property exists it is resized. In either case a pointer to the
1642  * property data is returned.
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 int fdt_setprop_placeholder(void *fdt, int nodeoffset, const char *name,
1661 			    int len, void **prop_data);
1662 
1663 /**
1664  * fdt_setprop_u32 - set a property to a 32-bit integer
1665  * @fdt: pointer to the device tree blob
1666  * @nodeoffset: offset of the node whose property to change
1667  * @name: name of the property to change
1668  * @val: 32-bit integer value for the property (native endian)
1669  *
1670  * fdt_setprop_u32() sets the value of the named property in the given
1671  * node to the given 32-bit integer value (converting to big-endian if
1672  * necessary), or creates a new property with that value if it does
1673  * not already exist.
1674  *
1675  * This function may insert or delete data from the blob, and will
1676  * therefore change the offsets of some existing nodes.
1677  *
1678  * returns:
1679  *	0, on success
1680  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1681  *		contain the new property value
1682  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1683  *	-FDT_ERR_BADLAYOUT,
1684  *	-FDT_ERR_BADMAGIC,
1685  *	-FDT_ERR_BADVERSION,
1686  *	-FDT_ERR_BADSTATE,
1687  *	-FDT_ERR_BADSTRUCTURE,
1688  *	-FDT_ERR_BADLAYOUT,
1689  *	-FDT_ERR_TRUNCATED, standard meanings
1690  */
1691 static inline int fdt_setprop_u32(void *fdt, int nodeoffset, const char *name,
1692 				  uint32_t val)
1693 {
1694 	fdt32_t tmp = cpu_to_fdt32(val);
1695 	return fdt_setprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1696 }
1697 
1698 /**
1699  * fdt_setprop_u64 - set a property to a 64-bit integer
1700  * @fdt: pointer to the device tree blob
1701  * @nodeoffset: offset of the node whose property to change
1702  * @name: name of the property to change
1703  * @val: 64-bit integer value for the property (native endian)
1704  *
1705  * fdt_setprop_u64() sets the value of the named property in the given
1706  * node to the given 64-bit integer value (converting to big-endian if
1707  * necessary), or creates a new property with that value if it does
1708  * not already exist.
1709  *
1710  * This function may insert or delete data from the blob, and will
1711  * therefore change the offsets of some existing nodes.
1712  *
1713  * returns:
1714  *	0, on success
1715  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1716  *		contain the new property value
1717  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1718  *	-FDT_ERR_BADLAYOUT,
1719  *	-FDT_ERR_BADMAGIC,
1720  *	-FDT_ERR_BADVERSION,
1721  *	-FDT_ERR_BADSTATE,
1722  *	-FDT_ERR_BADSTRUCTURE,
1723  *	-FDT_ERR_BADLAYOUT,
1724  *	-FDT_ERR_TRUNCATED, standard meanings
1725  */
1726 static inline int fdt_setprop_u64(void *fdt, int nodeoffset, const char *name,
1727 				  uint64_t val)
1728 {
1729 	fdt64_t tmp = cpu_to_fdt64(val);
1730 	return fdt_setprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1731 }
1732 
1733 /**
1734  * fdt_setprop_cell - set a property to a single cell value
1735  * @fdt: pointer to the device tree blob
1736  * @nodeoffset: offset of the node whose property to change
1737  * @name: name of the property to change
1738  * @val: 32-bit integer value for the property (native endian)
1739  *
1740  * This is an alternative name for fdt_setprop_u32()
1741  *
1742  * Return: 0 on success, negative libfdt error value otherwise.
1743  */
1744 static inline int fdt_setprop_cell(void *fdt, int nodeoffset, const char *name,
1745 				   uint32_t val)
1746 {
1747 	return fdt_setprop_u32(fdt, nodeoffset, name, val);
1748 }
1749 
1750 /**
1751  * fdt_setprop_string - set a property to a string value
1752  * @fdt: pointer to the device tree blob
1753  * @nodeoffset: offset of the node whose property to change
1754  * @name: name of the property to change
1755  * @str: string value for the property
1756  *
1757  * fdt_setprop_string() sets the value of the named property in the
1758  * given node to the given string value (using the length of the
1759  * string to determine the new length of the property), or creates a
1760  * new property with that value if it does not already exist.
1761  *
1762  * This function may insert or delete data from the blob, and will
1763  * therefore change the offsets of some existing nodes.
1764  *
1765  * returns:
1766  *	0, on success
1767  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1768  *		contain the new property value
1769  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1770  *	-FDT_ERR_BADLAYOUT,
1771  *	-FDT_ERR_BADMAGIC,
1772  *	-FDT_ERR_BADVERSION,
1773  *	-FDT_ERR_BADSTATE,
1774  *	-FDT_ERR_BADSTRUCTURE,
1775  *	-FDT_ERR_BADLAYOUT,
1776  *	-FDT_ERR_TRUNCATED, standard meanings
1777  */
1778 #define fdt_setprop_string(fdt, nodeoffset, name, str) \
1779 	fdt_setprop((fdt), (nodeoffset), (name), (str), strlen(str)+1)
1780 
1781 
1782 /**
1783  * fdt_setprop_empty - set a property to an empty value
1784  * @fdt: pointer to the device tree blob
1785  * @nodeoffset: offset of the node whose property to change
1786  * @name: name of the property to change
1787  *
1788  * fdt_setprop_empty() sets the value of the named property in the
1789  * given node to an empty (zero length) value, or creates a new empty
1790  * property if it does not already exist.
1791  *
1792  * This function may insert or delete data from the blob, and will
1793  * therefore change the offsets of some existing nodes.
1794  *
1795  * returns:
1796  *	0, on success
1797  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1798  *		contain the new property value
1799  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1800  *	-FDT_ERR_BADLAYOUT,
1801  *	-FDT_ERR_BADMAGIC,
1802  *	-FDT_ERR_BADVERSION,
1803  *	-FDT_ERR_BADSTATE,
1804  *	-FDT_ERR_BADSTRUCTURE,
1805  *	-FDT_ERR_BADLAYOUT,
1806  *	-FDT_ERR_TRUNCATED, standard meanings
1807  */
1808 #define fdt_setprop_empty(fdt, nodeoffset, name) \
1809 	fdt_setprop((fdt), (nodeoffset), (name), NULL, 0)
1810 
1811 /**
1812  * fdt_appendprop - append to or create a property
1813  * @fdt: pointer to the device tree blob
1814  * @nodeoffset: offset of the node whose property to change
1815  * @name: name of the property to append to
1816  * @val: pointer to data to append to the property value
1817  * @len: length of the data to append to the property value
1818  *
1819  * fdt_appendprop() appends the value to the named property in the
1820  * given node, creating the property if it does not already exist.
1821  *
1822  * This function may insert data into the blob, and will therefore
1823  * change the offsets of some existing nodes.
1824  *
1825  * returns:
1826  *	0, on success
1827  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1828  *		contain the new property value
1829  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1830  *	-FDT_ERR_BADLAYOUT,
1831  *	-FDT_ERR_BADMAGIC,
1832  *	-FDT_ERR_BADVERSION,
1833  *	-FDT_ERR_BADSTATE,
1834  *	-FDT_ERR_BADSTRUCTURE,
1835  *	-FDT_ERR_BADLAYOUT,
1836  *	-FDT_ERR_TRUNCATED, standard meanings
1837  */
1838 int fdt_appendprop(void *fdt, int nodeoffset, const char *name,
1839 		   const void *val, int len);
1840 
1841 /**
1842  * fdt_appendprop_u32 - append a 32-bit integer value to a property
1843  * @fdt: pointer to the device tree blob
1844  * @nodeoffset: offset of the node whose property to change
1845  * @name: name of the property to change
1846  * @val: 32-bit integer value to append to the property (native endian)
1847  *
1848  * fdt_appendprop_u32() appends the given 32-bit integer value
1849  * (converting to big-endian if necessary) to the value of the named
1850  * property in the given node, or creates a new property with that
1851  * value if it does not already exist.
1852  *
1853  * This function may insert data into the blob, and will therefore
1854  * change the offsets of some existing nodes.
1855  *
1856  * returns:
1857  *	0, on success
1858  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1859  *		contain the new property value
1860  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1861  *	-FDT_ERR_BADLAYOUT,
1862  *	-FDT_ERR_BADMAGIC,
1863  *	-FDT_ERR_BADVERSION,
1864  *	-FDT_ERR_BADSTATE,
1865  *	-FDT_ERR_BADSTRUCTURE,
1866  *	-FDT_ERR_BADLAYOUT,
1867  *	-FDT_ERR_TRUNCATED, standard meanings
1868  */
1869 static inline int fdt_appendprop_u32(void *fdt, int nodeoffset,
1870 				     const char *name, uint32_t val)
1871 {
1872 	fdt32_t tmp = cpu_to_fdt32(val);
1873 	return fdt_appendprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1874 }
1875 
1876 /**
1877  * fdt_appendprop_u64 - append a 64-bit integer value to a property
1878  * @fdt: pointer to the device tree blob
1879  * @nodeoffset: offset of the node whose property to change
1880  * @name: name of the property to change
1881  * @val: 64-bit integer value to append to the property (native endian)
1882  *
1883  * fdt_appendprop_u64() appends the given 64-bit integer value
1884  * (converting to big-endian if necessary) to the value of the named
1885  * property in the given node, or creates a new property with that
1886  * value if it does not already exist.
1887  *
1888  * This function may insert data into the blob, and will therefore
1889  * change the offsets of some existing nodes.
1890  *
1891  * returns:
1892  *	0, on success
1893  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1894  *		contain the new property value
1895  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1896  *	-FDT_ERR_BADLAYOUT,
1897  *	-FDT_ERR_BADMAGIC,
1898  *	-FDT_ERR_BADVERSION,
1899  *	-FDT_ERR_BADSTATE,
1900  *	-FDT_ERR_BADSTRUCTURE,
1901  *	-FDT_ERR_BADLAYOUT,
1902  *	-FDT_ERR_TRUNCATED, standard meanings
1903  */
1904 static inline int fdt_appendprop_u64(void *fdt, int nodeoffset,
1905 				     const char *name, uint64_t val)
1906 {
1907 	fdt64_t tmp = cpu_to_fdt64(val);
1908 	return fdt_appendprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1909 }
1910 
1911 /**
1912  * fdt_appendprop_cell - append a single cell value to a property
1913  * @fdt: pointer to the device tree blob
1914  * @nodeoffset: offset of the node whose property to change
1915  * @name: name of the property to change
1916  * @val: 32-bit integer value to append to the property (native endian)
1917  *
1918  * This is an alternative name for fdt_appendprop_u32()
1919  *
1920  * Return: 0 on success, negative libfdt error value otherwise.
1921  */
1922 static inline int fdt_appendprop_cell(void *fdt, int nodeoffset,
1923 				      const char *name, uint32_t val)
1924 {
1925 	return fdt_appendprop_u32(fdt, nodeoffset, name, val);
1926 }
1927 
1928 /**
1929  * fdt_appendprop_string - append a string to a property
1930  * @fdt: pointer to the device tree blob
1931  * @nodeoffset: offset of the node whose property to change
1932  * @name: name of the property to change
1933  * @str: string value to append to the property
1934  *
1935  * fdt_appendprop_string() appends the given string to the value of
1936  * the named property in the given node, or creates a new property
1937  * with that value if it does not already exist.
1938  *
1939  * This function may insert data into the blob, and will therefore
1940  * change the offsets of some existing nodes.
1941  *
1942  * returns:
1943  *	0, on success
1944  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1945  *		contain the new property value
1946  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1947  *	-FDT_ERR_BADLAYOUT,
1948  *	-FDT_ERR_BADMAGIC,
1949  *	-FDT_ERR_BADVERSION,
1950  *	-FDT_ERR_BADSTATE,
1951  *	-FDT_ERR_BADSTRUCTURE,
1952  *	-FDT_ERR_BADLAYOUT,
1953  *	-FDT_ERR_TRUNCATED, standard meanings
1954  */
1955 #define fdt_appendprop_string(fdt, nodeoffset, name, str) \
1956 	fdt_appendprop((fdt), (nodeoffset), (name), (str), strlen(str)+1)
1957 
1958 /**
1959  * fdt_appendprop_addrrange - append a address range property
1960  * @fdt: pointer to the device tree blob
1961  * @parent: offset of the parent node
1962  * @nodeoffset: offset of the node to add a property at
1963  * @name: name of property
1964  * @addr: start address of a given range
1965  * @size: size of a given range
1966  *
1967  * fdt_appendprop_addrrange() appends an address range value (start
1968  * address and size) to the value of the named property in the given
1969  * node, or creates a new property with that value if it does not
1970  * already exist.
1971  * If "name" is not specified, a default "reg" is used.
1972  * Cell sizes are determined by parent's #address-cells and #size-cells.
1973  *
1974  * This function may insert data into the blob, and will therefore
1975  * change the offsets of some existing nodes.
1976  *
1977  * returns:
1978  *	0, on success
1979  *	-FDT_ERR_BADLAYOUT,
1980  *	-FDT_ERR_BADMAGIC,
1981  *	-FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
1982  *		#address-cells property
1983  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1984  *	-FDT_ERR_BADSTATE,
1985  *	-FDT_ERR_BADSTRUCTURE,
1986  *	-FDT_ERR_BADVERSION,
1987  *	-FDT_ERR_BADVALUE, addr or size doesn't fit to respective cells size
1988  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1989  *		contain a new property
1990  *	-FDT_ERR_TRUNCATED, standard meanings
1991  */
1992 int fdt_appendprop_addrrange(void *fdt, int parent, int nodeoffset,
1993 			     const char *name, uint64_t addr, uint64_t size);
1994 
1995 /**
1996  * fdt_delprop - delete a property
1997  * @fdt: pointer to the device tree blob
1998  * @nodeoffset: offset of the node whose property to nop
1999  * @name: name of the property to nop
2000  *
2001  * fdt_del_property() will delete the given property.
2002  *
2003  * This function will delete data from the blob, and will therefore
2004  * change the offsets of some existing nodes.
2005  *
2006  * returns:
2007  *	0, on success
2008  *	-FDT_ERR_NOTFOUND, node does not have the named property
2009  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
2010  *	-FDT_ERR_BADLAYOUT,
2011  *	-FDT_ERR_BADMAGIC,
2012  *	-FDT_ERR_BADVERSION,
2013  *	-FDT_ERR_BADSTATE,
2014  *	-FDT_ERR_BADSTRUCTURE,
2015  *	-FDT_ERR_TRUNCATED, standard meanings
2016  */
2017 int fdt_delprop(void *fdt, int nodeoffset, const char *name);
2018 
2019 /**
2020  * fdt_add_subnode_namelen - creates a new node based on substring
2021  * @fdt: pointer to the device tree blob
2022  * @parentoffset: structure block offset of a node
2023  * @name: name of the subnode to create
2024  * @namelen: number of characters of name to consider
2025  *
2026  * Identical to fdt_add_subnode(), but use only the first @namelen
2027  * characters of @name as the name of the new node.  This is useful for
2028  * creating subnodes based on a portion of a larger string, such as a
2029  * full path.
2030  *
2031  * Return: structure block offset of the created subnode (>=0),
2032  *	   negative libfdt error value otherwise
2033  */
2034 #ifndef SWIG /* Not available in Python */
2035 int fdt_add_subnode_namelen(void *fdt, int parentoffset,
2036 			    const char *name, int namelen);
2037 #endif
2038 
2039 /**
2040  * fdt_add_subnode - creates a new node
2041  * @fdt: pointer to the device tree blob
2042  * @parentoffset: structure block offset of a node
2043  * @name: name of the subnode to locate
2044  *
2045  * fdt_add_subnode() creates a new node as a subnode of the node at
2046  * structure block offset parentoffset, with the given name (which
2047  * should include the unit address, if any).
2048  *
2049  * This function will insert data into the blob, and will therefore
2050  * change the offsets of some existing nodes.
2051  *
2052  * returns:
2053  *	structure block offset of the created nodeequested subnode (>=0), on
2054  *		success
2055  *	-FDT_ERR_NOTFOUND, if the requested subnode does not exist
2056  *	-FDT_ERR_BADOFFSET, if parentoffset did not point to an FDT_BEGIN_NODE
2057  *		tag
2058  *	-FDT_ERR_EXISTS, if the node at parentoffset already has a subnode of
2059  *		the given name
2060  *	-FDT_ERR_NOSPACE, if there is insufficient free space in the
2061  *		blob to contain the new node
2062  *	-FDT_ERR_NOSPACE
2063  *	-FDT_ERR_BADLAYOUT
2064  *      -FDT_ERR_BADMAGIC,
2065  *	-FDT_ERR_BADVERSION,
2066  *	-FDT_ERR_BADSTATE,
2067  *	-FDT_ERR_BADSTRUCTURE,
2068  *	-FDT_ERR_TRUNCATED, standard meanings.
2069  */
2070 int fdt_add_subnode(void *fdt, int parentoffset, const char *name);
2071 
2072 /**
2073  * fdt_del_node - delete a node (subtree)
2074  * @fdt: pointer to the device tree blob
2075  * @nodeoffset: offset of the node to nop
2076  *
2077  * fdt_del_node() will remove the given node, including all its
2078  * subnodes if any, from the blob.
2079  *
2080  * This function will delete data from the blob, and will therefore
2081  * change the offsets of some existing nodes.
2082  *
2083  * returns:
2084  *	0, on success
2085  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
2086  *	-FDT_ERR_BADLAYOUT,
2087  *	-FDT_ERR_BADMAGIC,
2088  *	-FDT_ERR_BADVERSION,
2089  *	-FDT_ERR_BADSTATE,
2090  *	-FDT_ERR_BADSTRUCTURE,
2091  *	-FDT_ERR_TRUNCATED, standard meanings
2092  */
2093 int fdt_del_node(void *fdt, int nodeoffset);
2094 
2095 /**
2096  * fdt_overlay_apply - Applies a DT overlay on a base DT
2097  * @fdt: pointer to the base device tree blob
2098  * @fdto: pointer to the device tree overlay blob
2099  *
2100  * fdt_overlay_apply() will apply the given device tree overlay on the
2101  * given base device tree.
2102  *
2103  * Expect the base device tree to be modified, even if the function
2104  * returns an error.
2105  *
2106  * returns:
2107  *	0, on success
2108  *	-FDT_ERR_NOSPACE, there's not enough space in the base device tree
2109  *	-FDT_ERR_NOTFOUND, the overlay points to some inexistant nodes or
2110  *		properties in the base DT
2111  *	-FDT_ERR_BADPHANDLE,
2112  *	-FDT_ERR_BADOVERLAY,
2113  *	-FDT_ERR_NOPHANDLES,
2114  *	-FDT_ERR_INTERNAL,
2115  *	-FDT_ERR_BADLAYOUT,
2116  *	-FDT_ERR_BADMAGIC,
2117  *	-FDT_ERR_BADOFFSET,
2118  *	-FDT_ERR_BADPATH,
2119  *	-FDT_ERR_BADVERSION,
2120  *	-FDT_ERR_BADSTRUCTURE,
2121  *	-FDT_ERR_BADSTATE,
2122  *	-FDT_ERR_TRUNCATED, standard meanings
2123  */
2124 int fdt_overlay_apply(void *fdt, void *fdto);
2125 
2126 /**
2127  * fdt_overlay_target_offset - retrieves the offset of a fragment's target
2128  * @fdt: Base device tree blob
2129  * @fdto: Device tree overlay blob
2130  * @fragment_offset: node offset of the fragment in the overlay
2131  * @pathp: pointer which receives the path of the target (or NULL)
2132  *
2133  * fdt_overlay_target_offset() retrieves the target offset in the base
2134  * device tree of a fragment, no matter how the actual targeting is
2135  * done (through a phandle or a path)
2136  *
2137  * returns:
2138  *      the targeted node offset in the base device tree
2139  *      Negative error code on error
2140  */
2141 int fdt_overlay_target_offset(const void *fdt, const void *fdto,
2142 			      int fragment_offset, char const **pathp);
2143 
2144 /**********************************************************************/
2145 /* Debugging / informational functions                                */
2146 /**********************************************************************/
2147 
2148 const char *fdt_strerror(int errval);
2149 
2150 #ifdef __cplusplus
2151 }
2152 #endif
2153 
2154 #endif /* LIBFDT_H */
2155