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      1 #ifndef _LIBFDT_H
      2 #define _LIBFDT_H
      3 /*
      4  * libfdt - Flat Device Tree manipulation
      5  * Copyright (C) 2006 David Gibson, IBM Corporation.
      6  *
      7  * libfdt is dual licensed: you can use it either under the terms of
      8  * the GPL, or the BSD license, at your option.
      9  *
     10  *  a) This library is free software; you can redistribute it and/or
     11  *     modify it under the terms of the GNU General Public License as
     12  *     published by the Free Software Foundation; either version 2 of the
     13  *     License, or (at your option) any later version.
     14  *
     15  *     This library is distributed in the hope that it will be useful,
     16  *     but WITHOUT ANY WARRANTY; without even the implied warranty of
     17  *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     18  *     GNU General Public License for more details.
     19  *
     20  *     You should have received a copy of the GNU General Public
     21  *     License along with this library; if not, write to the Free
     22  *     Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
     23  *     MA 02110-1301 USA
     24  *
     25  * Alternatively,
     26  *
     27  *  b) Redistribution and use in source and binary forms, with or
     28  *     without modification, are permitted provided that the following
     29  *     conditions are met:
     30  *
     31  *     1. Redistributions of source code must retain the above
     32  *        copyright notice, this list of conditions and the following
     33  *        disclaimer.
     34  *     2. Redistributions in binary form must reproduce the above
     35  *        copyright notice, this list of conditions and the following
     36  *        disclaimer in the documentation and/or other materials
     37  *        provided with the distribution.
     38  *
     39  *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
     40  *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
     41  *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     42  *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     43  *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
     44  *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     45  *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     46  *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     47  *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     48  *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     49  *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     50  *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
     51  *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     52  */
     53 
     54 #include <libfdt_env.h>
     55 #include <fdt.h>
     56 
     57 #define FDT_FIRST_SUPPORTED_VERSION	0x10
     58 #define FDT_LAST_SUPPORTED_VERSION	0x11
     59 
     60 /* Error codes: informative error codes */
     61 #define FDT_ERR_NOTFOUND	1
     62 	/* FDT_ERR_NOTFOUND: The requested node or property does not exist */
     63 #define FDT_ERR_EXISTS		2
     64 	/* FDT_ERR_EXISTS: Attempted to create a node or property which
     65 	 * already exists */
     66 #define FDT_ERR_NOSPACE		3
     67 	/* FDT_ERR_NOSPACE: Operation needed to expand the device
     68 	 * tree, but its buffer did not have sufficient space to
     69 	 * contain the expanded tree. Use fdt_open_into() to move the
     70 	 * device tree to a buffer with more space. */
     71 
     72 /* Error codes: codes for bad parameters */
     73 #define FDT_ERR_BADOFFSET	4
     74 	/* FDT_ERR_BADOFFSET: Function was passed a structure block
     75 	 * offset which is out-of-bounds, or which points to an
     76 	 * unsuitable part of the structure for the operation. */
     77 #define FDT_ERR_BADPATH		5
     78 	/* FDT_ERR_BADPATH: Function was passed a badly formatted path
     79 	 * (e.g. missing a leading / for a function which requires an
     80 	 * absolute path) */
     81 #define FDT_ERR_BADPHANDLE	6
     82 	/* FDT_ERR_BADPHANDLE: Function was passed an invalid phandle.
     83 	 * This can be caused either by an invalid phandle property
     84 	 * length, or the phandle value was either 0 or -1, which are
     85 	 * not permitted. */
     86 #define FDT_ERR_BADSTATE	7
     87 	/* FDT_ERR_BADSTATE: Function was passed an incomplete device
     88 	 * tree created by the sequential-write functions, which is
     89 	 * not sufficiently complete for the requested operation. */
     90 
     91 /* Error codes: codes for bad device tree blobs */
     92 #define FDT_ERR_TRUNCATED	8
     93 	/* FDT_ERR_TRUNCATED: Structure block of the given device tree
     94 	 * ends without an FDT_END tag. */
     95 #define FDT_ERR_BADMAGIC	9
     96 	/* FDT_ERR_BADMAGIC: Given "device tree" appears not to be a
     97 	 * device tree at all - it is missing the flattened device
     98 	 * tree magic number. */
     99 #define FDT_ERR_BADVERSION	10
    100 	/* FDT_ERR_BADVERSION: Given device tree has a version which
    101 	 * can't be handled by the requested operation.  For
    102 	 * read-write functions, this may mean that fdt_open_into() is
    103 	 * required to convert the tree to the expected version. */
    104 #define FDT_ERR_BADSTRUCTURE	11
    105 	/* FDT_ERR_BADSTRUCTURE: Given device tree has a corrupt
    106 	 * structure block or other serious error (e.g. misnested
    107 	 * nodes, or subnodes preceding properties). */
    108 #define FDT_ERR_BADLAYOUT	12
    109 	/* FDT_ERR_BADLAYOUT: For read-write functions, the given
    110 	 * device tree has it's sub-blocks in an order that the
    111 	 * function can't handle (memory reserve map, then structure,
    112 	 * then strings).  Use fdt_open_into() to reorganize the tree
    113 	 * into a form suitable for the read-write operations. */
    114 
    115 /* "Can't happen" error indicating a bug in libfdt */
    116 #define FDT_ERR_INTERNAL	13
    117 	/* FDT_ERR_INTERNAL: libfdt has failed an internal assertion.
    118 	 * Should never be returned, if it is, it indicates a bug in
    119 	 * libfdt itself. */
    120 
    121 /* Errors in device tree content */
    122 #define FDT_ERR_BADNCELLS	14
    123 	/* FDT_ERR_BADNCELLS: Device tree has a #address-cells, #size-cells
    124 	 * or similar property with a bad format or value */
    125 
    126 #define FDT_ERR_BADVALUE	15
    127 	/* FDT_ERR_BADVALUE: Device tree has a property with an unexpected
    128 	 * value. For example: a property expected to contain a string list
    129 	 * is not NUL-terminated within the length of its value. */
    130 
    131 #define FDT_ERR_BADOVERLAY	16
    132 	/* FDT_ERR_BADOVERLAY: The device tree overlay, while
    133 	 * correctly structured, cannot be applied due to some
    134 	 * unexpected or missing value, property or node. */
    135 
    136 #define FDT_ERR_NOPHANDLES	17
    137 	/* FDT_ERR_NOPHANDLES: The device tree doesn't have any
    138 	 * phandle available anymore without causing an overflow */
    139 
    140 #define FDT_ERR_MAX		17
    141 
    142 /**********************************************************************/
    143 /* Low-level functions (you probably don't need these)                */
    144 /**********************************************************************/
    145 
    146 #ifndef SWIG /* This function is not useful in Python */
    147 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int checklen);
    148 #endif
    149 static inline void *fdt_offset_ptr_w(void *fdt, int offset, int checklen)
    150 {
    151 	return (void *)(uintptr_t)fdt_offset_ptr(fdt, offset, checklen);
    152 }
    153 
    154 uint32_t fdt_next_tag(const void *fdt, int offset, int *nextoffset);
    155 
    156 /**********************************************************************/
    157 /* Traversal functions                                                */
    158 /**********************************************************************/
    159 
    160 int fdt_next_node(const void *fdt, int offset, int *depth);
    161 
    162 /**
    163  * fdt_first_subnode() - get offset of first direct subnode
    164  *
    165  * @fdt:	FDT blob
    166  * @offset:	Offset of node to check
    167  * @return offset of first subnode, or -FDT_ERR_NOTFOUND if there is none
    168  */
    169 int fdt_first_subnode(const void *fdt, int offset);
    170 
    171 /**
    172  * fdt_next_subnode() - get offset of next direct subnode
    173  *
    174  * After first calling fdt_first_subnode(), call this function repeatedly to
    175  * get direct subnodes of a parent node.
    176  *
    177  * @fdt:	FDT blob
    178  * @offset:	Offset of previous subnode
    179  * @return offset of next subnode, or -FDT_ERR_NOTFOUND if there are no more
    180  * subnodes
    181  */
    182 int fdt_next_subnode(const void *fdt, int offset);
    183 
    184 /**
    185  * fdt_for_each_subnode - iterate over all subnodes of a parent
    186  *
    187  * @node:	child node (int, lvalue)
    188  * @fdt:	FDT blob (const void *)
    189  * @parent:	parent node (int)
    190  *
    191  * This is actually a wrapper around a for loop and would be used like so:
    192  *
    193  *	fdt_for_each_subnode(node, fdt, parent) {
    194  *		Use node
    195  *		...
    196  *	}
    197  *
    198  *	if ((node < 0) && (node != -FDT_ERR_NOT_FOUND)) {
    199  *		Error handling
    200  *	}
    201  *
    202  * Note that this is implemented as a macro and @node is used as
    203  * iterator in the loop. The parent variable be constant or even a
    204  * literal.
    205  *
    206  */
    207 #define fdt_for_each_subnode(node, fdt, parent)		\
    208 	for (node = fdt_first_subnode(fdt, parent);	\
    209 	     node >= 0;					\
    210 	     node = fdt_next_subnode(fdt, node))
    211 
    212 /**********************************************************************/
    213 /* General functions                                                  */
    214 /**********************************************************************/
    215 #define fdt_get_header(fdt, field) \
    216 	(fdt32_to_cpu(((const struct fdt_header *)(fdt))->field))
    217 #define fdt_magic(fdt)			(fdt_get_header(fdt, magic))
    218 #define fdt_totalsize(fdt)		(fdt_get_header(fdt, totalsize))
    219 #define fdt_off_dt_struct(fdt)		(fdt_get_header(fdt, off_dt_struct))
    220 #define fdt_off_dt_strings(fdt)		(fdt_get_header(fdt, off_dt_strings))
    221 #define fdt_off_mem_rsvmap(fdt)		(fdt_get_header(fdt, off_mem_rsvmap))
    222 #define fdt_version(fdt)		(fdt_get_header(fdt, version))
    223 #define fdt_last_comp_version(fdt)	(fdt_get_header(fdt, last_comp_version))
    224 #define fdt_boot_cpuid_phys(fdt)	(fdt_get_header(fdt, boot_cpuid_phys))
    225 #define fdt_size_dt_strings(fdt)	(fdt_get_header(fdt, size_dt_strings))
    226 #define fdt_size_dt_struct(fdt)		(fdt_get_header(fdt, size_dt_struct))
    227 
    228 #define __fdt_set_hdr(name) \
    229 	static inline void fdt_set_##name(void *fdt, uint32_t val) \
    230 	{ \
    231 		struct fdt_header *fdth = (struct fdt_header *)fdt; \
    232 		fdth->name = cpu_to_fdt32(val); \
    233 	}
    234 __fdt_set_hdr(magic);
    235 __fdt_set_hdr(totalsize);
    236 __fdt_set_hdr(off_dt_struct);
    237 __fdt_set_hdr(off_dt_strings);
    238 __fdt_set_hdr(off_mem_rsvmap);
    239 __fdt_set_hdr(version);
    240 __fdt_set_hdr(last_comp_version);
    241 __fdt_set_hdr(boot_cpuid_phys);
    242 __fdt_set_hdr(size_dt_strings);
    243 __fdt_set_hdr(size_dt_struct);
    244 #undef __fdt_set_hdr
    245 
    246 /**
    247  * fdt_check_header - sanity check a device tree or possible device tree
    248  * @fdt: pointer to data which might be a flattened device tree
    249  *
    250  * fdt_check_header() checks that the given buffer contains what
    251  * appears to be a flattened device tree with sane information in its
    252  * header.
    253  *
    254  * returns:
    255  *     0, if the buffer appears to contain a valid device tree
    256  *     -FDT_ERR_BADMAGIC,
    257  *     -FDT_ERR_BADVERSION,
    258  *     -FDT_ERR_BADSTATE, standard meanings, as above
    259  */
    260 int fdt_check_header(const void *fdt);
    261 
    262 /**
    263  * fdt_move - move a device tree around in memory
    264  * @fdt: pointer to the device tree to move
    265  * @buf: pointer to memory where the device is to be moved
    266  * @bufsize: size of the memory space at buf
    267  *
    268  * fdt_move() relocates, if possible, the device tree blob located at
    269  * fdt to the buffer at buf of size bufsize.  The buffer may overlap
    270  * with the existing device tree blob at fdt.  Therefore,
    271  *     fdt_move(fdt, fdt, fdt_totalsize(fdt))
    272  * should always succeed.
    273  *
    274  * returns:
    275  *     0, on success
    276  *     -FDT_ERR_NOSPACE, bufsize is insufficient to contain the device tree
    277  *     -FDT_ERR_BADMAGIC,
    278  *     -FDT_ERR_BADVERSION,
    279  *     -FDT_ERR_BADSTATE, standard meanings
    280  */
    281 int fdt_move(const void *fdt, void *buf, int bufsize);
    282 
    283 /**********************************************************************/
    284 /* Read-only functions                                                */
    285 /**********************************************************************/
    286 
    287 /**
    288  * fdt_string - retrieve a string from the strings block of a device tree
    289  * @fdt: pointer to the device tree blob
    290  * @stroffset: offset of the string within the strings block (native endian)
    291  *
    292  * fdt_string() retrieves a pointer to a single string from the
    293  * strings block of the device tree blob at fdt.
    294  *
    295  * returns:
    296  *     a pointer to the string, on success
    297  *     NULL, if stroffset is out of bounds
    298  */
    299 const char *fdt_string(const void *fdt, int stroffset);
    300 
    301 /**
    302  * fdt_get_max_phandle - retrieves the highest phandle in a tree
    303  * @fdt: pointer to the device tree blob
    304  *
    305  * fdt_get_max_phandle retrieves the highest phandle in the given
    306  * device tree. This will ignore badly formatted phandles, or phandles
    307  * with a value of 0 or -1.
    308  *
    309  * returns:
    310  *      the highest phandle on success
    311  *      0, if no phandle was found in the device tree
    312  *      -1, if an error occurred
    313  */
    314 uint32_t fdt_get_max_phandle(const void *fdt);
    315 
    316 /**
    317  * fdt_num_mem_rsv - retrieve the number of memory reserve map entries
    318  * @fdt: pointer to the device tree blob
    319  *
    320  * Returns the number of entries in the device tree blob's memory
    321  * reservation map.  This does not include the terminating 0,0 entry
    322  * or any other (0,0) entries reserved for expansion.
    323  *
    324  * returns:
    325  *     the number of entries
    326  */
    327 int fdt_num_mem_rsv(const void *fdt);
    328 
    329 /**
    330  * fdt_get_mem_rsv - retrieve one memory reserve map entry
    331  * @fdt: pointer to the device tree blob
    332  * @address, @size: pointers to 64-bit variables
    333  *
    334  * On success, *address and *size will contain the address and size of
    335  * the n-th reserve map entry from the device tree blob, in
    336  * native-endian format.
    337  *
    338  * returns:
    339  *     0, on success
    340  *     -FDT_ERR_BADMAGIC,
    341  *     -FDT_ERR_BADVERSION,
    342  *     -FDT_ERR_BADSTATE, standard meanings
    343  */
    344 int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size);
    345 
    346 /**
    347  * fdt_subnode_offset_namelen - find a subnode based on substring
    348  * @fdt: pointer to the device tree blob
    349  * @parentoffset: structure block offset of a node
    350  * @name: name of the subnode to locate
    351  * @namelen: number of characters of name to consider
    352  *
    353  * Identical to fdt_subnode_offset(), but only examine the first
    354  * namelen characters of name for matching the subnode name.  This is
    355  * useful for finding subnodes based on a portion of a larger string,
    356  * such as a full path.
    357  */
    358 #ifndef SWIG /* Not available in Python */
    359 int fdt_subnode_offset_namelen(const void *fdt, int parentoffset,
    360 			       const char *name, int namelen);
    361 #endif
    362 /**
    363  * fdt_subnode_offset - find a subnode of a given node
    364  * @fdt: pointer to the device tree blob
    365  * @parentoffset: structure block offset of a node
    366  * @name: name of the subnode to locate
    367  *
    368  * fdt_subnode_offset() finds a subnode of the node at structure block
    369  * offset parentoffset with the given name.  name may include a unit
    370  * address, in which case fdt_subnode_offset() will find the subnode
    371  * with that unit address, or the unit address may be omitted, in
    372  * which case fdt_subnode_offset() will find an arbitrary subnode
    373  * whose name excluding unit address matches the given name.
    374  *
    375  * returns:
    376  *	structure block offset of the requested subnode (>=0), on success
    377  *	-FDT_ERR_NOTFOUND, if the requested subnode does not exist
    378  *	-FDT_ERR_BADOFFSET, if parentoffset did not point to an FDT_BEGIN_NODE
    379  *		tag
    380  *	-FDT_ERR_BADMAGIC,
    381  *	-FDT_ERR_BADVERSION,
    382  *	-FDT_ERR_BADSTATE,
    383  *	-FDT_ERR_BADSTRUCTURE,
    384  *	-FDT_ERR_TRUNCATED, standard meanings.
    385  */
    386 int fdt_subnode_offset(const void *fdt, int parentoffset, const char *name);
    387 
    388 /**
    389  * fdt_path_offset_namelen - find a tree node by its full path
    390  * @fdt: pointer to the device tree blob
    391  * @path: full path of the node to locate
    392  * @namelen: number of characters of path to consider
    393  *
    394  * Identical to fdt_path_offset(), but only consider the first namelen
    395  * characters of path as the path name.
    396  */
    397 #ifndef SWIG /* Not available in Python */
    398 int fdt_path_offset_namelen(const void *fdt, const char *path, int namelen);
    399 #endif
    400 
    401 /**
    402  * fdt_path_offset - find a tree node by its full path
    403  * @fdt: pointer to the device tree blob
    404  * @path: full path of the node to locate
    405  *
    406  * fdt_path_offset() finds a node of a given path in the device tree.
    407  * Each path component may omit the unit address portion, but the
    408  * results of this are undefined if any such path component is
    409  * ambiguous (that is if there are multiple nodes at the relevant
    410  * level matching the given component, differentiated only by unit
    411  * address).
    412  *
    413  * returns:
    414  *	structure block offset of the node with the requested path (>=0), on
    415  *		success
    416  *	-FDT_ERR_BADPATH, given path does not begin with '/' or is invalid
    417  *	-FDT_ERR_NOTFOUND, if the requested node does not exist
    418  *      -FDT_ERR_BADMAGIC,
    419  *	-FDT_ERR_BADVERSION,
    420  *	-FDT_ERR_BADSTATE,
    421  *	-FDT_ERR_BADSTRUCTURE,
    422  *	-FDT_ERR_TRUNCATED, standard meanings.
    423  */
    424 int fdt_path_offset(const void *fdt, const char *path);
    425 
    426 /**
    427  * fdt_get_name - retrieve the name of a given node
    428  * @fdt: pointer to the device tree blob
    429  * @nodeoffset: structure block offset of the starting node
    430  * @lenp: pointer to an integer variable (will be overwritten) or NULL
    431  *
    432  * fdt_get_name() retrieves the name (including unit address) of the
    433  * device tree node at structure block offset nodeoffset.  If lenp is
    434  * non-NULL, the length of this name is also returned, in the integer
    435  * pointed to by lenp.
    436  *
    437  * returns:
    438  *	pointer to the node's name, on success
    439  *		If lenp is non-NULL, *lenp contains the length of that name
    440  *			(>=0)
    441  *	NULL, on error
    442  *		if lenp is non-NULL *lenp contains an error code (<0):
    443  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
    444  *			tag
    445  *		-FDT_ERR_BADMAGIC,
    446  *		-FDT_ERR_BADVERSION,
    447  *		-FDT_ERR_BADSTATE, standard meanings
    448  */
    449 const char *fdt_get_name(const void *fdt, int nodeoffset, int *lenp);
    450 
    451 /**
    452  * fdt_first_property_offset - find the offset of a node's first property
    453  * @fdt: pointer to the device tree blob
    454  * @nodeoffset: structure block offset of a node
    455  *
    456  * fdt_first_property_offset() finds the first property of the node at
    457  * the given structure block offset.
    458  *
    459  * returns:
    460  *	structure block offset of the property (>=0), on success
    461  *	-FDT_ERR_NOTFOUND, if the requested node has no properties
    462  *	-FDT_ERR_BADOFFSET, if nodeoffset did not point to an FDT_BEGIN_NODE tag
    463  *      -FDT_ERR_BADMAGIC,
    464  *	-FDT_ERR_BADVERSION,
    465  *	-FDT_ERR_BADSTATE,
    466  *	-FDT_ERR_BADSTRUCTURE,
    467  *	-FDT_ERR_TRUNCATED, standard meanings.
    468  */
    469 int fdt_first_property_offset(const void *fdt, int nodeoffset);
    470 
    471 /**
    472  * fdt_next_property_offset - step through a node's properties
    473  * @fdt: pointer to the device tree blob
    474  * @offset: structure block offset of a property
    475  *
    476  * fdt_next_property_offset() finds the property immediately after the
    477  * one at the given structure block offset.  This will be a property
    478  * of the same node as the given property.
    479  *
    480  * returns:
    481  *	structure block offset of the next property (>=0), on success
    482  *	-FDT_ERR_NOTFOUND, if the given property is the last in its node
    483  *	-FDT_ERR_BADOFFSET, if nodeoffset did not point to an FDT_PROP tag
    484  *      -FDT_ERR_BADMAGIC,
    485  *	-FDT_ERR_BADVERSION,
    486  *	-FDT_ERR_BADSTATE,
    487  *	-FDT_ERR_BADSTRUCTURE,
    488  *	-FDT_ERR_TRUNCATED, standard meanings.
    489  */
    490 int fdt_next_property_offset(const void *fdt, int offset);
    491 
    492 /**
    493  * fdt_for_each_property_offset - iterate over all properties of a node
    494  *
    495  * @property_offset:	property offset (int, lvalue)
    496  * @fdt:		FDT blob (const void *)
    497  * @node:		node offset (int)
    498  *
    499  * This is actually a wrapper around a for loop and would be used like so:
    500  *
    501  *	fdt_for_each_property_offset(property, fdt, node) {
    502  *		Use property
    503  *		...
    504  *	}
    505  *
    506  *	if ((property < 0) && (property != -FDT_ERR_NOT_FOUND)) {
    507  *		Error handling
    508  *	}
    509  *
    510  * Note that this is implemented as a macro and property is used as
    511  * iterator in the loop. The node variable can be constant or even a
    512  * literal.
    513  */
    514 #define fdt_for_each_property_offset(property, fdt, node)	\
    515 	for (property = fdt_first_property_offset(fdt, node);	\
    516 	     property >= 0;					\
    517 	     property = fdt_next_property_offset(fdt, property))
    518 
    519 /**
    520  * fdt_get_property_by_offset - retrieve the property at a given offset
    521  * @fdt: pointer to the device tree blob
    522  * @offset: offset of the property to retrieve
    523  * @lenp: pointer to an integer variable (will be overwritten) or NULL
    524  *
    525  * fdt_get_property_by_offset() retrieves a pointer to the
    526  * fdt_property structure within the device tree blob at the given
    527  * offset.  If lenp is non-NULL, the length of the property value is
    528  * also returned, in the integer pointed to by lenp.
    529  *
    530  * returns:
    531  *	pointer to the structure representing the property
    532  *		if lenp is non-NULL, *lenp contains the length of the property
    533  *		value (>=0)
    534  *	NULL, on error
    535  *		if lenp is non-NULL, *lenp contains an error code (<0):
    536  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_PROP tag
    537  *		-FDT_ERR_BADMAGIC,
    538  *		-FDT_ERR_BADVERSION,
    539  *		-FDT_ERR_BADSTATE,
    540  *		-FDT_ERR_BADSTRUCTURE,
    541  *		-FDT_ERR_TRUNCATED, standard meanings
    542  */
    543 const struct fdt_property *fdt_get_property_by_offset(const void *fdt,
    544 						      int offset,
    545 						      int *lenp);
    546 
    547 /**
    548  * fdt_get_property_namelen - find a property based on substring
    549  * @fdt: pointer to the device tree blob
    550  * @nodeoffset: offset of the node whose property to find
    551  * @name: name of the property to find
    552  * @namelen: number of characters of name to consider
    553  * @lenp: pointer to an integer variable (will be overwritten) or NULL
    554  *
    555  * Identical to fdt_get_property(), but only examine the first namelen
    556  * characters of name for matching the property name.
    557  */
    558 #ifndef SWIG /* Not available in Python */
    559 const struct fdt_property *fdt_get_property_namelen(const void *fdt,
    560 						    int nodeoffset,
    561 						    const char *name,
    562 						    int namelen, int *lenp);
    563 #endif
    564 
    565 /**
    566  * fdt_get_property - find a given property in a given node
    567  * @fdt: pointer to the device tree blob
    568  * @nodeoffset: offset of the node whose property to find
    569  * @name: name of the property to find
    570  * @lenp: pointer to an integer variable (will be overwritten) or NULL
    571  *
    572  * fdt_get_property() retrieves a pointer to the fdt_property
    573  * structure within the device tree blob corresponding to the property
    574  * named 'name' of the node at offset nodeoffset.  If lenp is
    575  * non-NULL, the length of the property value is also returned, in the
    576  * integer pointed to by lenp.
    577  *
    578  * returns:
    579  *	pointer to the structure representing the property
    580  *		if lenp is non-NULL, *lenp contains the length of the property
    581  *		value (>=0)
    582  *	NULL, on error
    583  *		if lenp is non-NULL, *lenp contains an error code (<0):
    584  *		-FDT_ERR_NOTFOUND, node does not have named property
    585  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
    586  *			tag
    587  *		-FDT_ERR_BADMAGIC,
    588  *		-FDT_ERR_BADVERSION,
    589  *		-FDT_ERR_BADSTATE,
    590  *		-FDT_ERR_BADSTRUCTURE,
    591  *		-FDT_ERR_TRUNCATED, standard meanings
    592  */
    593 const struct fdt_property *fdt_get_property(const void *fdt, int nodeoffset,
    594 					    const char *name, int *lenp);
    595 static inline struct fdt_property *fdt_get_property_w(void *fdt, int nodeoffset,
    596 						      const char *name,
    597 						      int *lenp)
    598 {
    599 	return (struct fdt_property *)(uintptr_t)
    600 		fdt_get_property(fdt, nodeoffset, name, lenp);
    601 }
    602 
    603 /**
    604  * fdt_getprop_by_offset - retrieve the value of a property at a given offset
    605  * @fdt: pointer to the device tree blob
    606  * @ffset: offset of the property to read
    607  * @namep: pointer to a string variable (will be overwritten) or NULL
    608  * @lenp: pointer to an integer variable (will be overwritten) or NULL
    609  *
    610  * fdt_getprop_by_offset() retrieves a pointer to the value of the
    611  * property at structure block offset 'offset' (this will be a pointer
    612  * to within the device blob itself, not a copy of the value).  If
    613  * lenp is non-NULL, the length of the property value is also
    614  * returned, in the integer pointed to by lenp.  If namep is non-NULL,
    615  * the property's namne will also be returned in the char * pointed to
    616  * by namep (this will be a pointer to within the device tree's string
    617  * block, not a new copy of the name).
    618  *
    619  * returns:
    620  *	pointer to the property's value
    621  *		if lenp is non-NULL, *lenp contains the length of the property
    622  *		value (>=0)
    623  *		if namep is non-NULL *namep contiains a pointer to the property
    624  *		name.
    625  *	NULL, on error
    626  *		if lenp is non-NULL, *lenp contains an error code (<0):
    627  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_PROP tag
    628  *		-FDT_ERR_BADMAGIC,
    629  *		-FDT_ERR_BADVERSION,
    630  *		-FDT_ERR_BADSTATE,
    631  *		-FDT_ERR_BADSTRUCTURE,
    632  *		-FDT_ERR_TRUNCATED, standard meanings
    633  */
    634 #ifndef SWIG /* This function is not useful in Python */
    635 const void *fdt_getprop_by_offset(const void *fdt, int offset,
    636 				  const char **namep, int *lenp);
    637 #endif
    638 
    639 /**
    640  * fdt_getprop_namelen - get property value based on substring
    641  * @fdt: pointer to the device tree blob
    642  * @nodeoffset: offset of the node whose property to find
    643  * @name: name of the property to find
    644  * @namelen: number of characters of name to consider
    645  * @lenp: pointer to an integer variable (will be overwritten) or NULL
    646  *
    647  * Identical to fdt_getprop(), but only examine the first namelen
    648  * characters of name for matching the property name.
    649  */
    650 #ifndef SWIG /* Not available in Python */
    651 const void *fdt_getprop_namelen(const void *fdt, int nodeoffset,
    652 				const char *name, int namelen, int *lenp);
    653 static inline void *fdt_getprop_namelen_w(void *fdt, int nodeoffset,
    654 					  const char *name, int namelen,
    655 					  int *lenp)
    656 {
    657 	return (void *)(uintptr_t)fdt_getprop_namelen(fdt, nodeoffset, name,
    658 						      namelen, lenp);
    659 }
    660 #endif
    661 
    662 /**
    663  * fdt_getprop - retrieve the value of a given property
    664  * @fdt: pointer to the device tree blob
    665  * @nodeoffset: offset of the node whose property to find
    666  * @name: name of the property to find
    667  * @lenp: pointer to an integer variable (will be overwritten) or NULL
    668  *
    669  * fdt_getprop() retrieves a pointer to the value of the property
    670  * named 'name' of the node at offset nodeoffset (this will be a
    671  * pointer to within the device blob itself, not a copy of the value).
    672  * If lenp is non-NULL, the length of the property value is also
    673  * returned, in the integer pointed to by lenp.
    674  *
    675  * returns:
    676  *	pointer to the property's value
    677  *		if lenp is non-NULL, *lenp contains the length of the property
    678  *		value (>=0)
    679  *	NULL, on error
    680  *		if lenp is non-NULL, *lenp contains an error code (<0):
    681  *		-FDT_ERR_NOTFOUND, node does not have named property
    682  *		-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
    683  *			tag
    684  *		-FDT_ERR_BADMAGIC,
    685  *		-FDT_ERR_BADVERSION,
    686  *		-FDT_ERR_BADSTATE,
    687  *		-FDT_ERR_BADSTRUCTURE,
    688  *		-FDT_ERR_TRUNCATED, standard meanings
    689  */
    690 const void *fdt_getprop(const void *fdt, int nodeoffset,
    691 			const char *name, int *lenp);
    692 static inline void *fdt_getprop_w(void *fdt, int nodeoffset,
    693 				  const char *name, int *lenp)
    694 {
    695 	return (void *)(uintptr_t)fdt_getprop(fdt, nodeoffset, name, lenp);
    696 }
    697 
    698 /**
    699  * fdt_get_phandle - retrieve the phandle of a given node
    700  * @fdt: pointer to the device tree blob
    701  * @nodeoffset: structure block offset of the node
    702  *
    703  * fdt_get_phandle() retrieves the phandle of the device tree node at
    704  * structure block offset nodeoffset.
    705  *
    706  * returns:
    707  *	the phandle of the node at nodeoffset, on success (!= 0, != -1)
    708  *	0, if the node has no phandle, or another error occurs
    709  */
    710 uint32_t fdt_get_phandle(const void *fdt, int nodeoffset);
    711 
    712 /**
    713  * fdt_get_alias_namelen - get alias based on substring
    714  * @fdt: pointer to the device tree blob
    715  * @name: name of the alias th look up
    716  * @namelen: number of characters of name to consider
    717  *
    718  * Identical to fdt_get_alias(), but only examine the first namelen
    719  * characters of name for matching the alias name.
    720  */
    721 #ifndef SWIG /* Not available in Python */
    722 const char *fdt_get_alias_namelen(const void *fdt,
    723 				  const char *name, int namelen);
    724 #endif
    725 
    726 /**
    727  * fdt_get_alias - retrieve the path referenced by a given alias
    728  * @fdt: pointer to the device tree blob
    729  * @name: name of the alias th look up
    730  *
    731  * fdt_get_alias() retrieves the value of a given alias.  That is, the
    732  * value of the property named 'name' in the node /aliases.
    733  *
    734  * returns:
    735  *	a pointer to the expansion of the alias named 'name', if it exists
    736  *	NULL, if the given alias or the /aliases node does not exist
    737  */
    738 const char *fdt_get_alias(const void *fdt, const char *name);
    739 
    740 /**
    741  * fdt_get_path - determine the full path of a node
    742  * @fdt: pointer to the device tree blob
    743  * @nodeoffset: offset of the node whose path to find
    744  * @buf: character buffer to contain the returned path (will be overwritten)
    745  * @buflen: size of the character buffer at buf
    746  *
    747  * fdt_get_path() computes the full path of the node at offset
    748  * nodeoffset, and records that path in the buffer at buf.
    749  *
    750  * NOTE: This function is expensive, as it must scan the device tree
    751  * structure from the start to nodeoffset.
    752  *
    753  * returns:
    754  *	0, on success
    755  *		buf contains the absolute path of the node at
    756  *		nodeoffset, as a NUL-terminated string.
    757  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
    758  *	-FDT_ERR_NOSPACE, the path of the given node is longer than (bufsize-1)
    759  *		characters and will not fit in the given buffer.
    760  *	-FDT_ERR_BADMAGIC,
    761  *	-FDT_ERR_BADVERSION,
    762  *	-FDT_ERR_BADSTATE,
    763  *	-FDT_ERR_BADSTRUCTURE, standard meanings
    764  */
    765 int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen);
    766 
    767 /**
    768  * fdt_supernode_atdepth_offset - find a specific ancestor of a node
    769  * @fdt: pointer to the device tree blob
    770  * @nodeoffset: offset of the node whose parent to find
    771  * @supernodedepth: depth of the ancestor to find
    772  * @nodedepth: pointer to an integer variable (will be overwritten) or NULL
    773  *
    774  * fdt_supernode_atdepth_offset() finds an ancestor of the given node
    775  * at a specific depth from the root (where the root itself has depth
    776  * 0, its immediate subnodes depth 1 and so forth).  So
    777  *	fdt_supernode_atdepth_offset(fdt, nodeoffset, 0, NULL);
    778  * will always return 0, the offset of the root node.  If the node at
    779  * nodeoffset has depth D, then:
    780  *	fdt_supernode_atdepth_offset(fdt, nodeoffset, D, NULL);
    781  * will return nodeoffset itself.
    782  *
    783  * NOTE: This function is expensive, as it must scan the device tree
    784  * structure from the start to nodeoffset.
    785  *
    786  * returns:
    787  *	structure block offset of the node at node offset's ancestor
    788  *		of depth supernodedepth (>=0), on success
    789  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
    790  *	-FDT_ERR_NOTFOUND, supernodedepth was greater than the depth of
    791  *		nodeoffset
    792  *	-FDT_ERR_BADMAGIC,
    793  *	-FDT_ERR_BADVERSION,
    794  *	-FDT_ERR_BADSTATE,
    795  *	-FDT_ERR_BADSTRUCTURE, standard meanings
    796  */
    797 int fdt_supernode_atdepth_offset(const void *fdt, int nodeoffset,
    798 				 int supernodedepth, int *nodedepth);
    799 
    800 /**
    801  * fdt_node_depth - find the depth of a given node
    802  * @fdt: pointer to the device tree blob
    803  * @nodeoffset: offset of the node whose parent to find
    804  *
    805  * fdt_node_depth() finds the depth of a given node.  The root node
    806  * has depth 0, its immediate subnodes depth 1 and so forth.
    807  *
    808  * NOTE: This function is expensive, as it must scan the device tree
    809  * structure from the start to nodeoffset.
    810  *
    811  * returns:
    812  *	depth of the node at nodeoffset (>=0), on success
    813  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
    814  *	-FDT_ERR_BADMAGIC,
    815  *	-FDT_ERR_BADVERSION,
    816  *	-FDT_ERR_BADSTATE,
    817  *	-FDT_ERR_BADSTRUCTURE, standard meanings
    818  */
    819 int fdt_node_depth(const void *fdt, int nodeoffset);
    820 
    821 /**
    822  * fdt_parent_offset - find the parent of a given node
    823  * @fdt: pointer to the device tree blob
    824  * @nodeoffset: offset of the node whose parent to find
    825  *
    826  * fdt_parent_offset() locates the parent node of a given node (that
    827  * is, it finds the offset of the node which contains the node at
    828  * nodeoffset as a subnode).
    829  *
    830  * NOTE: This function is expensive, as it must scan the device tree
    831  * structure from the start to nodeoffset, *twice*.
    832  *
    833  * returns:
    834  *	structure block offset of the parent of the node at nodeoffset
    835  *		(>=0), on success
    836  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
    837  *	-FDT_ERR_BADMAGIC,
    838  *	-FDT_ERR_BADVERSION,
    839  *	-FDT_ERR_BADSTATE,
    840  *	-FDT_ERR_BADSTRUCTURE, standard meanings
    841  */
    842 int fdt_parent_offset(const void *fdt, int nodeoffset);
    843 
    844 /**
    845  * fdt_node_offset_by_prop_value - find nodes with a given property value
    846  * @fdt: pointer to the device tree blob
    847  * @startoffset: only find nodes after this offset
    848  * @propname: property name to check
    849  * @propval: property value to search for
    850  * @proplen: length of the value in propval
    851  *
    852  * fdt_node_offset_by_prop_value() returns the offset of the first
    853  * node after startoffset, which has a property named propname whose
    854  * value is of length proplen and has value equal to propval; or if
    855  * startoffset is -1, the very first such node in the tree.
    856  *
    857  * To iterate through all nodes matching the criterion, the following
    858  * idiom can be used:
    859  *	offset = fdt_node_offset_by_prop_value(fdt, -1, propname,
    860  *					       propval, proplen);
    861  *	while (offset != -FDT_ERR_NOTFOUND) {
    862  *		// other code here
    863  *		offset = fdt_node_offset_by_prop_value(fdt, offset, propname,
    864  *						       propval, proplen);
    865  *	}
    866  *
    867  * Note the -1 in the first call to the function, if 0 is used here
    868  * instead, the function will never locate the root node, even if it
    869  * matches the criterion.
    870  *
    871  * returns:
    872  *	structure block offset of the located node (>= 0, >startoffset),
    873  *		 on success
    874  *	-FDT_ERR_NOTFOUND, no node matching the criterion exists in the
    875  *		tree after startoffset
    876  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
    877  *	-FDT_ERR_BADMAGIC,
    878  *	-FDT_ERR_BADVERSION,
    879  *	-FDT_ERR_BADSTATE,
    880  *	-FDT_ERR_BADSTRUCTURE, standard meanings
    881  */
    882 int fdt_node_offset_by_prop_value(const void *fdt, int startoffset,
    883 				  const char *propname,
    884 				  const void *propval, int proplen);
    885 
    886 /**
    887  * fdt_node_offset_by_phandle - find the node with a given phandle
    888  * @fdt: pointer to the device tree blob
    889  * @phandle: phandle value
    890  *
    891  * fdt_node_offset_by_phandle() returns the offset of the node
    892  * which has the given phandle value.  If there is more than one node
    893  * in the tree with the given phandle (an invalid tree), results are
    894  * undefined.
    895  *
    896  * returns:
    897  *	structure block offset of the located node (>= 0), on success
    898  *	-FDT_ERR_NOTFOUND, no node with that phandle exists
    899  *	-FDT_ERR_BADPHANDLE, given phandle value was invalid (0 or -1)
    900  *	-FDT_ERR_BADMAGIC,
    901  *	-FDT_ERR_BADVERSION,
    902  *	-FDT_ERR_BADSTATE,
    903  *	-FDT_ERR_BADSTRUCTURE, standard meanings
    904  */
    905 int fdt_node_offset_by_phandle(const void *fdt, uint32_t phandle);
    906 
    907 /**
    908  * fdt_node_check_compatible: check a node's compatible property
    909  * @fdt: pointer to the device tree blob
    910  * @nodeoffset: offset of a tree node
    911  * @compatible: string to match against
    912  *
    913  *
    914  * fdt_node_check_compatible() returns 0 if the given node contains a
    915  * 'compatible' property with the given string as one of its elements,
    916  * it returns non-zero otherwise, or on error.
    917  *
    918  * returns:
    919  *	0, if the node has a 'compatible' property listing the given string
    920  *	1, if the node has a 'compatible' property, but it does not list
    921  *		the given string
    922  *	-FDT_ERR_NOTFOUND, if the given node has no 'compatible' property
    923  *	-FDT_ERR_BADOFFSET, if nodeoffset does not refer to a BEGIN_NODE tag
    924  *	-FDT_ERR_BADMAGIC,
    925  *	-FDT_ERR_BADVERSION,
    926  *	-FDT_ERR_BADSTATE,
    927  *	-FDT_ERR_BADSTRUCTURE, standard meanings
    928  */
    929 int fdt_node_check_compatible(const void *fdt, int nodeoffset,
    930 			      const char *compatible);
    931 
    932 /**
    933  * fdt_node_offset_by_compatible - find nodes with a given 'compatible' value
    934  * @fdt: pointer to the device tree blob
    935  * @startoffset: only find nodes after this offset
    936  * @compatible: 'compatible' string to match against
    937  *
    938  * fdt_node_offset_by_compatible() returns the offset of the first
    939  * node after startoffset, which has a 'compatible' property which
    940  * lists the given compatible string; or if startoffset is -1, the
    941  * very first such node in the tree.
    942  *
    943  * To iterate through all nodes matching the criterion, the following
    944  * idiom can be used:
    945  *	offset = fdt_node_offset_by_compatible(fdt, -1, compatible);
    946  *	while (offset != -FDT_ERR_NOTFOUND) {
    947  *		// other code here
    948  *		offset = fdt_node_offset_by_compatible(fdt, offset, compatible);
    949  *	}
    950  *
    951  * Note the -1 in the first call to the function, if 0 is used here
    952  * instead, the function will never locate the root node, even if it
    953  * matches the criterion.
    954  *
    955  * returns:
    956  *	structure block offset of the located node (>= 0, >startoffset),
    957  *		 on success
    958  *	-FDT_ERR_NOTFOUND, no node matching the criterion exists in the
    959  *		tree after startoffset
    960  *	-FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
    961  *	-FDT_ERR_BADMAGIC,
    962  *	-FDT_ERR_BADVERSION,
    963  *	-FDT_ERR_BADSTATE,
    964  *	-FDT_ERR_BADSTRUCTURE, standard meanings
    965  */
    966 int fdt_node_offset_by_compatible(const void *fdt, int startoffset,
    967 				  const char *compatible);
    968 
    969 /**
    970  * fdt_stringlist_contains - check a string list property for a string
    971  * @strlist: Property containing a list of strings to check
    972  * @listlen: Length of property
    973  * @str: String to search for
    974  *
    975  * This is a utility function provided for convenience. The list contains
    976  * one or more strings, each terminated by \0, as is found in a device tree
    977  * "compatible" property.
    978  *
    979  * @return: 1 if the string is found in the list, 0 not found, or invalid list
    980  */
    981 int fdt_stringlist_contains(const char *strlist, int listlen, const char *str);
    982 
    983 /**
    984  * fdt_stringlist_count - count the number of strings in a string list
    985  * @fdt: pointer to the device tree blob
    986  * @nodeoffset: offset of a tree node
    987  * @property: name of the property containing the string list
    988  * @return:
    989  *   the number of strings in the given property
    990  *   -FDT_ERR_BADVALUE if the property value is not NUL-terminated
    991  *   -FDT_ERR_NOTFOUND if the property does not exist
    992  */
    993 int fdt_stringlist_count(const void *fdt, int nodeoffset, const char *property);
    994 
    995 /**
    996  * fdt_stringlist_search - find a string in a string list and return its index
    997  * @fdt: pointer to the device tree blob
    998  * @nodeoffset: offset of a tree node
    999  * @property: name of the property containing the string list
   1000  * @string: string to look up in the string list
   1001  *
   1002  * Note that it is possible for this function to succeed on property values
   1003  * that are not NUL-terminated. That's because the function will stop after
   1004  * finding the first occurrence of @string. This can for example happen with
   1005  * small-valued cell properties, such as #address-cells, when searching for
   1006  * the empty string.
   1007  *
   1008  * @return:
   1009  *   the index of the string in the list of strings
   1010  *   -FDT_ERR_BADVALUE if the property value is not NUL-terminated
   1011  *   -FDT_ERR_NOTFOUND if the property does not exist or does not contain
   1012  *                     the given string
   1013  */
   1014 int fdt_stringlist_search(const void *fdt, int nodeoffset, const char *property,
   1015 			  const char *string);
   1016 
   1017 /**
   1018  * fdt_stringlist_get() - obtain the string at a given index in a string list
   1019  * @fdt: pointer to the device tree blob
   1020  * @nodeoffset: offset of a tree node
   1021  * @property: name of the property containing the string list
   1022  * @index: index of the string to return
   1023  * @lenp: return location for the string length or an error code on failure
   1024  *
   1025  * Note that this will successfully extract strings from properties with
   1026  * non-NUL-terminated values. For example on small-valued cell properties
   1027  * this function will return the empty string.
   1028  *
   1029  * If non-NULL, the length of the string (on success) or a negative error-code
   1030  * (on failure) will be stored in the integer pointer to by lenp.
   1031  *
   1032  * @return:
   1033  *   A pointer to the string at the given index in the string list or NULL on
   1034  *   failure. On success the length of the string will be stored in the memory
   1035  *   location pointed to by the lenp parameter, if non-NULL. On failure one of
   1036  *   the following negative error codes will be returned in the lenp parameter
   1037  *   (if non-NULL):
   1038  *     -FDT_ERR_BADVALUE if the property value is not NUL-terminated
   1039  *     -FDT_ERR_NOTFOUND if the property does not exist
   1040  */
   1041 const char *fdt_stringlist_get(const void *fdt, int nodeoffset,
   1042 			       const char *property, int index,
   1043 			       int *lenp);
   1044 
   1045 /**********************************************************************/
   1046 /* Read-only functions (addressing related)                           */
   1047 /**********************************************************************/
   1048 
   1049 /**
   1050  * FDT_MAX_NCELLS - maximum value for #address-cells and #size-cells
   1051  *
   1052  * This is the maximum value for #address-cells, #size-cells and
   1053  * similar properties that will be processed by libfdt.  IEE1275
   1054  * requires that OF implementations handle values up to 4.
   1055  * Implementations may support larger values, but in practice higher
   1056  * values aren't used.
   1057  */
   1058 #define FDT_MAX_NCELLS		4
   1059 
   1060 /**
   1061  * fdt_address_cells - retrieve address size for a bus represented in the tree
   1062  * @fdt: pointer to the device tree blob
   1063  * @nodeoffset: offset of the node to find the address size for
   1064  *
   1065  * When the node has a valid #address-cells property, returns its value.
   1066  *
   1067  * returns:
   1068  *	0 <= n < FDT_MAX_NCELLS, on success
   1069  *      2, if the node has no #address-cells property
   1070  *      -FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
   1071  *		#address-cells property
   1072  *	-FDT_ERR_BADMAGIC,
   1073  *	-FDT_ERR_BADVERSION,
   1074  *	-FDT_ERR_BADSTATE,
   1075  *	-FDT_ERR_BADSTRUCTURE,
   1076  *	-FDT_ERR_TRUNCATED, standard meanings
   1077  */
   1078 int fdt_address_cells(const void *fdt, int nodeoffset);
   1079 
   1080 /**
   1081  * fdt_size_cells - retrieve address range size for a bus represented in the
   1082  *                  tree
   1083  * @fdt: pointer to the device tree blob
   1084  * @nodeoffset: offset of the node to find the address range size for
   1085  *
   1086  * When the node has a valid #size-cells property, returns its value.
   1087  *
   1088  * returns:
   1089  *	0 <= n < FDT_MAX_NCELLS, on success
   1090  *      2, if the node has no #address-cells property
   1091  *      -FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
   1092  *		#size-cells property
   1093  *	-FDT_ERR_BADMAGIC,
   1094  *	-FDT_ERR_BADVERSION,
   1095  *	-FDT_ERR_BADSTATE,
   1096  *	-FDT_ERR_BADSTRUCTURE,
   1097  *	-FDT_ERR_TRUNCATED, standard meanings
   1098  */
   1099 int fdt_size_cells(const void *fdt, int nodeoffset);
   1100 
   1101 
   1102 /**********************************************************************/
   1103 /* Write-in-place functions                                           */
   1104 /**********************************************************************/
   1105 
   1106 /**
   1107  * fdt_setprop_inplace_namelen_partial - change a property's value,
   1108  *                                       but not its size
   1109  * @fdt: pointer to the device tree blob
   1110  * @nodeoffset: offset of the node whose property to change
   1111  * @name: name of the property to change
   1112  * @namelen: number of characters of name to consider
   1113  * @idx: index of the property to change in the array
   1114  * @val: pointer to data to replace the property value with
   1115  * @len: length of the property value
   1116  *
   1117  * Identical to fdt_setprop_inplace(), but modifies the given property
   1118  * starting from the given index, and using only the first characters
   1119  * of the name. It is useful when you want to manipulate only one value of
   1120  * an array and you have a string that doesn't end with \0.
   1121  */
   1122 #ifndef SWIG /* Not available in Python */
   1123 int fdt_setprop_inplace_namelen_partial(void *fdt, int nodeoffset,
   1124 					const char *name, int namelen,
   1125 					uint32_t idx, const void *val,
   1126 					int len);
   1127 #endif
   1128 
   1129 /**
   1130  * fdt_setprop_inplace - change a property's value, but not its size
   1131  * @fdt: pointer to the device tree blob
   1132  * @nodeoffset: offset of the node whose property to change
   1133  * @name: name of the property to change
   1134  * @val: pointer to data to replace the property value with
   1135  * @len: length of the property value
   1136  *
   1137  * fdt_setprop_inplace() replaces the value of a given property with
   1138  * the data in val, of length len.  This function cannot change the
   1139  * size of a property, and so will only work if len is equal to the
   1140  * current length of the property.
   1141  *
   1142  * This function will alter only the bytes in the blob which contain
   1143  * the given property value, and will not alter or move any other part
   1144  * of the tree.
   1145  *
   1146  * returns:
   1147  *	0, on success
   1148  *	-FDT_ERR_NOSPACE, if len is not equal to the property's current length
   1149  *	-FDT_ERR_NOTFOUND, node does not have the named property
   1150  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
   1151  *	-FDT_ERR_BADMAGIC,
   1152  *	-FDT_ERR_BADVERSION,
   1153  *	-FDT_ERR_BADSTATE,
   1154  *	-FDT_ERR_BADSTRUCTURE,
   1155  *	-FDT_ERR_TRUNCATED, standard meanings
   1156  */
   1157 #ifndef SWIG /* Not available in Python */
   1158 int fdt_setprop_inplace(void *fdt, int nodeoffset, const char *name,
   1159 			const void *val, int len);
   1160 #endif
   1161 
   1162 /**
   1163  * fdt_setprop_inplace_u32 - change the value of a 32-bit integer property
   1164  * @fdt: pointer to the device tree blob
   1165  * @nodeoffset: offset of the node whose property to change
   1166  * @name: name of the property to change
   1167  * @val: 32-bit integer value to replace the property with
   1168  *
   1169  * fdt_setprop_inplace_u32() replaces the value of a given property
   1170  * with the 32-bit integer value in val, converting val to big-endian
   1171  * if necessary.  This function cannot change the size of a property,
   1172  * and so will only work if the property already exists and has length
   1173  * 4.
   1174  *
   1175  * This function will alter only the bytes in the blob which contain
   1176  * the given property value, and will not alter or move any other part
   1177  * of the tree.
   1178  *
   1179  * returns:
   1180  *	0, on success
   1181  *	-FDT_ERR_NOSPACE, if the property's length is not equal to 4
   1182  *	-FDT_ERR_NOTFOUND, node does not have the named property
   1183  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
   1184  *	-FDT_ERR_BADMAGIC,
   1185  *	-FDT_ERR_BADVERSION,
   1186  *	-FDT_ERR_BADSTATE,
   1187  *	-FDT_ERR_BADSTRUCTURE,
   1188  *	-FDT_ERR_TRUNCATED, standard meanings
   1189  */
   1190 static inline int fdt_setprop_inplace_u32(void *fdt, int nodeoffset,
   1191 					  const char *name, uint32_t val)
   1192 {
   1193 	fdt32_t tmp = cpu_to_fdt32(val);
   1194 	return fdt_setprop_inplace(fdt, nodeoffset, name, &tmp, sizeof(tmp));
   1195 }
   1196 
   1197 /**
   1198  * fdt_setprop_inplace_u64 - change the value of a 64-bit integer property
   1199  * @fdt: pointer to the device tree blob
   1200  * @nodeoffset: offset of the node whose property to change
   1201  * @name: name of the property to change
   1202  * @val: 64-bit integer value to replace the property with
   1203  *
   1204  * fdt_setprop_inplace_u64() replaces the value of a given property
   1205  * with the 64-bit integer value in val, converting val to big-endian
   1206  * if necessary.  This function cannot change the size of a property,
   1207  * and so will only work if the property already exists and has length
   1208  * 8.
   1209  *
   1210  * This function will alter only the bytes in the blob which contain
   1211  * the given property value, and will not alter or move any other part
   1212  * of the tree.
   1213  *
   1214  * returns:
   1215  *	0, on success
   1216  *	-FDT_ERR_NOSPACE, if the property's length is not equal to 8
   1217  *	-FDT_ERR_NOTFOUND, node does not have the named property
   1218  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
   1219  *	-FDT_ERR_BADMAGIC,
   1220  *	-FDT_ERR_BADVERSION,
   1221  *	-FDT_ERR_BADSTATE,
   1222  *	-FDT_ERR_BADSTRUCTURE,
   1223  *	-FDT_ERR_TRUNCATED, standard meanings
   1224  */
   1225 static inline int fdt_setprop_inplace_u64(void *fdt, int nodeoffset,
   1226 					  const char *name, uint64_t val)
   1227 {
   1228 	fdt64_t tmp = cpu_to_fdt64(val);
   1229 	return fdt_setprop_inplace(fdt, nodeoffset, name, &tmp, sizeof(tmp));
   1230 }
   1231 
   1232 /**
   1233  * fdt_setprop_inplace_cell - change the value of a single-cell property
   1234  *
   1235  * This is an alternative name for fdt_setprop_inplace_u32()
   1236  */
   1237 static inline int fdt_setprop_inplace_cell(void *fdt, int nodeoffset,
   1238 					   const char *name, uint32_t val)
   1239 {
   1240 	return fdt_setprop_inplace_u32(fdt, nodeoffset, name, val);
   1241 }
   1242 
   1243 /**
   1244  * fdt_nop_property - replace a property with nop tags
   1245  * @fdt: pointer to the device tree blob
   1246  * @nodeoffset: offset of the node whose property to nop
   1247  * @name: name of the property to nop
   1248  *
   1249  * fdt_nop_property() will replace a given property's representation
   1250  * in the blob with FDT_NOP tags, effectively removing it from the
   1251  * tree.
   1252  *
   1253  * This function will alter only the bytes in the blob which contain
   1254  * the property, and will not alter or move any other part of the
   1255  * tree.
   1256  *
   1257  * returns:
   1258  *	0, on success
   1259  *	-FDT_ERR_NOTFOUND, node does not have the named property
   1260  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
   1261  *	-FDT_ERR_BADMAGIC,
   1262  *	-FDT_ERR_BADVERSION,
   1263  *	-FDT_ERR_BADSTATE,
   1264  *	-FDT_ERR_BADSTRUCTURE,
   1265  *	-FDT_ERR_TRUNCATED, standard meanings
   1266  */
   1267 int fdt_nop_property(void *fdt, int nodeoffset, const char *name);
   1268 
   1269 /**
   1270  * fdt_nop_node - replace a node (subtree) with nop tags
   1271  * @fdt: pointer to the device tree blob
   1272  * @nodeoffset: offset of the node to nop
   1273  *
   1274  * fdt_nop_node() will replace a given node's representation in the
   1275  * blob, including all its subnodes, if any, with FDT_NOP tags,
   1276  * effectively removing it from the tree.
   1277  *
   1278  * This function will alter only the bytes in the blob which contain
   1279  * the node and its properties and subnodes, and will not alter or
   1280  * move any other part of the tree.
   1281  *
   1282  * returns:
   1283  *	0, on success
   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 int fdt_nop_node(void *fdt, int nodeoffset);
   1292 
   1293 /**********************************************************************/
   1294 /* Sequential write functions                                         */
   1295 /**********************************************************************/
   1296 
   1297 int fdt_create(void *buf, int bufsize);
   1298 int fdt_resize(void *fdt, void *buf, int bufsize);
   1299 int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size);
   1300 int fdt_finish_reservemap(void *fdt);
   1301 int fdt_begin_node(void *fdt, const char *name);
   1302 int fdt_property(void *fdt, const char *name, const void *val, int len);
   1303 static inline int fdt_property_u32(void *fdt, const char *name, uint32_t val)
   1304 {
   1305 	fdt32_t tmp = cpu_to_fdt32(val);
   1306 	return fdt_property(fdt, name, &tmp, sizeof(tmp));
   1307 }
   1308 static inline int fdt_property_u64(void *fdt, const char *name, uint64_t val)
   1309 {
   1310 	fdt64_t tmp = cpu_to_fdt64(val);
   1311 	return fdt_property(fdt, name, &tmp, sizeof(tmp));
   1312 }
   1313 static inline int fdt_property_cell(void *fdt, const char *name, uint32_t val)
   1314 {
   1315 	return fdt_property_u32(fdt, name, val);
   1316 }
   1317 
   1318 /**
   1319  * fdt_property_placeholder - add a new property and return a ptr to its value
   1320  *
   1321  * @fdt: pointer to the device tree blob
   1322  * @name: name of property to add
   1323  * @len: length of property value in bytes
   1324  * @valp: returns a pointer to where where the value should be placed
   1325  *
   1326  * returns:
   1327  *	0, on success
   1328  *	-FDT_ERR_BADMAGIC,
   1329  *	-FDT_ERR_NOSPACE, standard meanings
   1330  */
   1331 int fdt_property_placeholder(void *fdt, const char *name, int len, void **valp);
   1332 
   1333 #define fdt_property_string(fdt, name, str) \
   1334 	fdt_property(fdt, name, str, strlen(str)+1)
   1335 int fdt_end_node(void *fdt);
   1336 int fdt_finish(void *fdt);
   1337 
   1338 /**********************************************************************/
   1339 /* Read-write functions                                               */
   1340 /**********************************************************************/
   1341 
   1342 int fdt_create_empty_tree(void *buf, int bufsize);
   1343 int fdt_open_into(const void *fdt, void *buf, int bufsize);
   1344 int fdt_pack(void *fdt);
   1345 
   1346 /**
   1347  * fdt_add_mem_rsv - add one memory reserve map entry
   1348  * @fdt: pointer to the device tree blob
   1349  * @address, @size: 64-bit values (native endian)
   1350  *
   1351  * Adds a reserve map entry to the given blob reserving a region at
   1352  * address address of length size.
   1353  *
   1354  * This function will insert data into the reserve map and will
   1355  * therefore change the indexes of some entries in the table.
   1356  *
   1357  * returns:
   1358  *	0, on success
   1359  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
   1360  *		contain the new reservation entry
   1361  *	-FDT_ERR_BADMAGIC,
   1362  *	-FDT_ERR_BADVERSION,
   1363  *	-FDT_ERR_BADSTATE,
   1364  *	-FDT_ERR_BADSTRUCTURE,
   1365  *	-FDT_ERR_BADLAYOUT,
   1366  *	-FDT_ERR_TRUNCATED, standard meanings
   1367  */
   1368 int fdt_add_mem_rsv(void *fdt, uint64_t address, uint64_t size);
   1369 
   1370 /**
   1371  * fdt_del_mem_rsv - remove a memory reserve map entry
   1372  * @fdt: pointer to the device tree blob
   1373  * @n: entry to remove
   1374  *
   1375  * fdt_del_mem_rsv() removes the n-th memory reserve map entry from
   1376  * the blob.
   1377  *
   1378  * This function will delete data from the reservation table and will
   1379  * therefore change the indexes of some entries in the table.
   1380  *
   1381  * returns:
   1382  *	0, on success
   1383  *	-FDT_ERR_NOTFOUND, there is no entry of the given index (i.e. there
   1384  *		are less than n+1 reserve map entries)
   1385  *	-FDT_ERR_BADMAGIC,
   1386  *	-FDT_ERR_BADVERSION,
   1387  *	-FDT_ERR_BADSTATE,
   1388  *	-FDT_ERR_BADSTRUCTURE,
   1389  *	-FDT_ERR_BADLAYOUT,
   1390  *	-FDT_ERR_TRUNCATED, standard meanings
   1391  */
   1392 int fdt_del_mem_rsv(void *fdt, int n);
   1393 
   1394 /**
   1395  * fdt_set_name - change the name of a given node
   1396  * @fdt: pointer to the device tree blob
   1397  * @nodeoffset: structure block offset of a node
   1398  * @name: name to give the node
   1399  *
   1400  * fdt_set_name() replaces the name (including unit address, if any)
   1401  * of the given node with the given string.  NOTE: this function can't
   1402  * efficiently check if the new name is unique amongst the given
   1403  * node's siblings; results are undefined if this function is invoked
   1404  * with a name equal to one of the given node's siblings.
   1405  *
   1406  * This function may insert or delete data from the blob, and will
   1407  * therefore change the offsets of some existing nodes.
   1408  *
   1409  * returns:
   1410  *	0, on success
   1411  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob
   1412  *		to contain the new name
   1413  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
   1414  *	-FDT_ERR_BADMAGIC,
   1415  *	-FDT_ERR_BADVERSION,
   1416  *	-FDT_ERR_BADSTATE, standard meanings
   1417  */
   1418 int fdt_set_name(void *fdt, int nodeoffset, const char *name);
   1419 
   1420 /**
   1421  * fdt_setprop - create or change a property
   1422  * @fdt: pointer to the device tree blob
   1423  * @nodeoffset: offset of the node whose property to change
   1424  * @name: name of the property to change
   1425  * @val: pointer to data to set the property value to
   1426  * @len: length of the property value
   1427  *
   1428  * fdt_setprop() sets the value of the named property in the given
   1429  * node to the given value and length, creating the property if it
   1430  * does not already exist.
   1431  *
   1432  * This function may insert or delete data from the blob, and will
   1433  * therefore change the offsets of some existing nodes.
   1434  *
   1435  * returns:
   1436  *	0, on success
   1437  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
   1438  *		contain the new property value
   1439  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
   1440  *	-FDT_ERR_BADLAYOUT,
   1441  *	-FDT_ERR_BADMAGIC,
   1442  *	-FDT_ERR_BADVERSION,
   1443  *	-FDT_ERR_BADSTATE,
   1444  *	-FDT_ERR_BADSTRUCTURE,
   1445  *	-FDT_ERR_BADLAYOUT,
   1446  *	-FDT_ERR_TRUNCATED, standard meanings
   1447  */
   1448 int fdt_setprop(void *fdt, int nodeoffset, const char *name,
   1449 		const void *val, int len);
   1450 
   1451 /**
   1452  * fdt_setprop_u32 - set a property to a 32-bit integer
   1453  * @fdt: pointer to the device tree blob
   1454  * @nodeoffset: offset of the node whose property to change
   1455  * @name: name of the property to change
   1456  * @val: 32-bit integer value for the property (native endian)
   1457  *
   1458  * fdt_setprop_u32() sets the value of the named property in the given
   1459  * node to the given 32-bit integer value (converting to big-endian if
   1460  * necessary), or creates a new property with that value if it does
   1461  * not already exist.
   1462  *
   1463  * This function may insert or delete data from the blob, and will
   1464  * therefore change the offsets of some existing nodes.
   1465  *
   1466  * returns:
   1467  *	0, on success
   1468  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
   1469  *		contain the new property value
   1470  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
   1471  *	-FDT_ERR_BADLAYOUT,
   1472  *	-FDT_ERR_BADMAGIC,
   1473  *	-FDT_ERR_BADVERSION,
   1474  *	-FDT_ERR_BADSTATE,
   1475  *	-FDT_ERR_BADSTRUCTURE,
   1476  *	-FDT_ERR_BADLAYOUT,
   1477  *	-FDT_ERR_TRUNCATED, standard meanings
   1478  */
   1479 static inline int fdt_setprop_u32(void *fdt, int nodeoffset, const char *name,
   1480 				  uint32_t val)
   1481 {
   1482 	fdt32_t tmp = cpu_to_fdt32(val);
   1483 	return fdt_setprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
   1484 }
   1485 
   1486 /**
   1487  * fdt_setprop_u64 - set a property to a 64-bit integer
   1488  * @fdt: pointer to the device tree blob
   1489  * @nodeoffset: offset of the node whose property to change
   1490  * @name: name of the property to change
   1491  * @val: 64-bit integer value for the property (native endian)
   1492  *
   1493  * fdt_setprop_u64() sets the value of the named property in the given
   1494  * node to the given 64-bit integer value (converting to big-endian if
   1495  * necessary), or creates a new property with that value if it does
   1496  * not already exist.
   1497  *
   1498  * This function may insert or delete data from the blob, and will
   1499  * therefore change the offsets of some existing nodes.
   1500  *
   1501  * returns:
   1502  *	0, on success
   1503  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
   1504  *		contain the new property value
   1505  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
   1506  *	-FDT_ERR_BADLAYOUT,
   1507  *	-FDT_ERR_BADMAGIC,
   1508  *	-FDT_ERR_BADVERSION,
   1509  *	-FDT_ERR_BADSTATE,
   1510  *	-FDT_ERR_BADSTRUCTURE,
   1511  *	-FDT_ERR_BADLAYOUT,
   1512  *	-FDT_ERR_TRUNCATED, standard meanings
   1513  */
   1514 static inline int fdt_setprop_u64(void *fdt, int nodeoffset, const char *name,
   1515 				  uint64_t val)
   1516 {
   1517 	fdt64_t tmp = cpu_to_fdt64(val);
   1518 	return fdt_setprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
   1519 }
   1520 
   1521 /**
   1522  * fdt_setprop_cell - set a property to a single cell value
   1523  *
   1524  * This is an alternative name for fdt_setprop_u32()
   1525  */
   1526 static inline int fdt_setprop_cell(void *fdt, int nodeoffset, const char *name,
   1527 				   uint32_t val)
   1528 {
   1529 	return fdt_setprop_u32(fdt, nodeoffset, name, val);
   1530 }
   1531 
   1532 /**
   1533  * fdt_setprop_string - set a property to a string value
   1534  * @fdt: pointer to the device tree blob
   1535  * @nodeoffset: offset of the node whose property to change
   1536  * @name: name of the property to change
   1537  * @str: string value for the property
   1538  *
   1539  * fdt_setprop_string() sets the value of the named property in the
   1540  * given node to the given string value (using the length of the
   1541  * string to determine the new length of the property), or creates a
   1542  * new property with that value if it does not already exist.
   1543  *
   1544  * This function may insert or delete data from the blob, and will
   1545  * therefore change the offsets of some existing nodes.
   1546  *
   1547  * returns:
   1548  *	0, on success
   1549  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
   1550  *		contain the new property value
   1551  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
   1552  *	-FDT_ERR_BADLAYOUT,
   1553  *	-FDT_ERR_BADMAGIC,
   1554  *	-FDT_ERR_BADVERSION,
   1555  *	-FDT_ERR_BADSTATE,
   1556  *	-FDT_ERR_BADSTRUCTURE,
   1557  *	-FDT_ERR_BADLAYOUT,
   1558  *	-FDT_ERR_TRUNCATED, standard meanings
   1559  */
   1560 #define fdt_setprop_string(fdt, nodeoffset, name, str) \
   1561 	fdt_setprop((fdt), (nodeoffset), (name), (str), strlen(str)+1)
   1562 
   1563 
   1564 /**
   1565  * fdt_setprop_empty - set a property to an empty value
   1566  * @fdt: pointer to the device tree blob
   1567  * @nodeoffset: offset of the node whose property to change
   1568  * @name: name of the property to change
   1569  *
   1570  * fdt_setprop_empty() sets the value of the named property in the
   1571  * given node to an empty (zero length) value, or creates a new empty
   1572  * property if it does not already exist.
   1573  *
   1574  * This function may insert or delete data from the blob, and will
   1575  * therefore change the offsets of some existing nodes.
   1576  *
   1577  * returns:
   1578  *	0, on success
   1579  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
   1580  *		contain the new property value
   1581  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
   1582  *	-FDT_ERR_BADLAYOUT,
   1583  *	-FDT_ERR_BADMAGIC,
   1584  *	-FDT_ERR_BADVERSION,
   1585  *	-FDT_ERR_BADSTATE,
   1586  *	-FDT_ERR_BADSTRUCTURE,
   1587  *	-FDT_ERR_BADLAYOUT,
   1588  *	-FDT_ERR_TRUNCATED, standard meanings
   1589  */
   1590 #define fdt_setprop_empty(fdt, nodeoffset, name) \
   1591 	fdt_setprop((fdt), (nodeoffset), (name), NULL, 0)
   1592 
   1593 /**
   1594  * fdt_appendprop - append to or create a property
   1595  * @fdt: pointer to the device tree blob
   1596  * @nodeoffset: offset of the node whose property to change
   1597  * @name: name of the property to append to
   1598  * @val: pointer to data to append to the property value
   1599  * @len: length of the data to append to the property value
   1600  *
   1601  * fdt_appendprop() appends the value to the named property in the
   1602  * given node, creating the property if it does not already exist.
   1603  *
   1604  * This function may insert data into the blob, and will therefore
   1605  * change the offsets of some existing nodes.
   1606  *
   1607  * returns:
   1608  *	0, on success
   1609  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
   1610  *		contain the new property value
   1611  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
   1612  *	-FDT_ERR_BADLAYOUT,
   1613  *	-FDT_ERR_BADMAGIC,
   1614  *	-FDT_ERR_BADVERSION,
   1615  *	-FDT_ERR_BADSTATE,
   1616  *	-FDT_ERR_BADSTRUCTURE,
   1617  *	-FDT_ERR_BADLAYOUT,
   1618  *	-FDT_ERR_TRUNCATED, standard meanings
   1619  */
   1620 int fdt_appendprop(void *fdt, int nodeoffset, const char *name,
   1621 		   const void *val, int len);
   1622 
   1623 /**
   1624  * fdt_appendprop_u32 - append a 32-bit integer value to a property
   1625  * @fdt: pointer to the device tree blob
   1626  * @nodeoffset: offset of the node whose property to change
   1627  * @name: name of the property to change
   1628  * @val: 32-bit integer value to append to the property (native endian)
   1629  *
   1630  * fdt_appendprop_u32() appends the given 32-bit integer value
   1631  * (converting to big-endian if necessary) to the value of the named
   1632  * property in the given node, or creates a new property with that
   1633  * value if it does not already exist.
   1634  *
   1635  * This function may insert data into the blob, and will therefore
   1636  * change the offsets of some existing nodes.
   1637  *
   1638  * returns:
   1639  *	0, on success
   1640  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
   1641  *		contain the new property value
   1642  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
   1643  *	-FDT_ERR_BADLAYOUT,
   1644  *	-FDT_ERR_BADMAGIC,
   1645  *	-FDT_ERR_BADVERSION,
   1646  *	-FDT_ERR_BADSTATE,
   1647  *	-FDT_ERR_BADSTRUCTURE,
   1648  *	-FDT_ERR_BADLAYOUT,
   1649  *	-FDT_ERR_TRUNCATED, standard meanings
   1650  */
   1651 static inline int fdt_appendprop_u32(void *fdt, int nodeoffset,
   1652 				     const char *name, uint32_t val)
   1653 {
   1654 	fdt32_t tmp = cpu_to_fdt32(val);
   1655 	return fdt_appendprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
   1656 }
   1657 
   1658 /**
   1659  * fdt_appendprop_u64 - append a 64-bit integer value to a property
   1660  * @fdt: pointer to the device tree blob
   1661  * @nodeoffset: offset of the node whose property to change
   1662  * @name: name of the property to change
   1663  * @val: 64-bit integer value to append to the property (native endian)
   1664  *
   1665  * fdt_appendprop_u64() appends the given 64-bit integer value
   1666  * (converting to big-endian if necessary) to the value of the named
   1667  * property in the given node, or creates a new property with that
   1668  * value if it does not already exist.
   1669  *
   1670  * This function may insert data into the blob, and will therefore
   1671  * change the offsets of some existing nodes.
   1672  *
   1673  * returns:
   1674  *	0, on success
   1675  *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
   1676  *		contain the new property value
   1677  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
   1678  *	-FDT_ERR_BADLAYOUT,
   1679  *	-FDT_ERR_BADMAGIC,
   1680  *	-FDT_ERR_BADVERSION,
   1681  *	-FDT_ERR_BADSTATE,
   1682  *	-FDT_ERR_BADSTRUCTURE,
   1683  *	-FDT_ERR_BADLAYOUT,
   1684  *	-FDT_ERR_TRUNCATED, standard meanings
   1685  */
   1686 static inline int fdt_appendprop_u64(void *fdt, int nodeoffset,
   1687 				     const char *name, uint64_t val)
   1688 {
   1689 	fdt64_t tmp = cpu_to_fdt64(val);
   1690 	return fdt_appendprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
   1691 }
   1692 
   1693 /**
   1694  * fdt_appendprop_cell - append a single cell value to a property
   1695  *
   1696  * This is an alternative name for fdt_appendprop_u32()
   1697  */
   1698 static inline int fdt_appendprop_cell(void *fdt, int nodeoffset,
   1699 				      const char *name, uint32_t val)
   1700 {
   1701 	return fdt_appendprop_u32(fdt, nodeoffset, name, val);
   1702 }
   1703 
   1704 /**
   1705  * fdt_appendprop_string - append a string to a property
   1706  * @fdt: pointer to the device tree blob
   1707  * @nodeoffset: offset of the node whose property to change
   1708  * @name: name of the property to change
   1709  * @str: string value to append to the property
   1710  *
   1711  * fdt_appendprop_string() appends the given string to the value of
   1712  * the named property in the given node, or creates a new property
   1713  * with that value if it does not already exist.
   1714  *
   1715  * This function may insert data into the blob, and will therefore
   1716  * 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_appendprop_string(fdt, nodeoffset, name, str) \
   1732 	fdt_appendprop((fdt), (nodeoffset), (name), (str), strlen(str)+1)
   1733 
   1734 /**
   1735  * fdt_delprop - delete a property
   1736  * @fdt: pointer to the device tree blob
   1737  * @nodeoffset: offset of the node whose property to nop
   1738  * @name: name of the property to nop
   1739  *
   1740  * fdt_del_property() will delete the given property.
   1741  *
   1742  * This function will delete data from the blob, and will therefore
   1743  * change the offsets of some existing nodes.
   1744  *
   1745  * returns:
   1746  *	0, on success
   1747  *	-FDT_ERR_NOTFOUND, node does not have the named property
   1748  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
   1749  *	-FDT_ERR_BADLAYOUT,
   1750  *	-FDT_ERR_BADMAGIC,
   1751  *	-FDT_ERR_BADVERSION,
   1752  *	-FDT_ERR_BADSTATE,
   1753  *	-FDT_ERR_BADSTRUCTURE,
   1754  *	-FDT_ERR_TRUNCATED, standard meanings
   1755  */
   1756 int fdt_delprop(void *fdt, int nodeoffset, const char *name);
   1757 
   1758 /**
   1759  * fdt_add_subnode_namelen - creates a new node based on substring
   1760  * @fdt: pointer to the device tree blob
   1761  * @parentoffset: structure block offset of a node
   1762  * @name: name of the subnode to locate
   1763  * @namelen: number of characters of name to consider
   1764  *
   1765  * Identical to fdt_add_subnode(), but use only the first namelen
   1766  * characters of name as the name of the new node.  This is useful for
   1767  * creating subnodes based on a portion of a larger string, such as a
   1768  * full path.
   1769  */
   1770 #ifndef SWIG /* Not available in Python */
   1771 int fdt_add_subnode_namelen(void *fdt, int parentoffset,
   1772 			    const char *name, int namelen);
   1773 #endif
   1774 
   1775 /**
   1776  * fdt_add_subnode - creates a new node
   1777  * @fdt: pointer to the device tree blob
   1778  * @parentoffset: structure block offset of a node
   1779  * @name: name of the subnode to locate
   1780  *
   1781  * fdt_add_subnode() creates a new node as a subnode of the node at
   1782  * structure block offset parentoffset, with the given name (which
   1783  * should include the unit address, if any).
   1784  *
   1785  * This function will insert data into the blob, and will therefore
   1786  * change the offsets of some existing nodes.
   1787 
   1788  * returns:
   1789  *	structure block offset of the created nodeequested subnode (>=0), on
   1790  *		success
   1791  *	-FDT_ERR_NOTFOUND, if the requested subnode does not exist
   1792  *	-FDT_ERR_BADOFFSET, if parentoffset did not point to an FDT_BEGIN_NODE
   1793  *		tag
   1794  *	-FDT_ERR_EXISTS, if the node at parentoffset already has a subnode of
   1795  *		the given name
   1796  *	-FDT_ERR_NOSPACE, if there is insufficient free space in the
   1797  *		blob to contain the new node
   1798  *	-FDT_ERR_NOSPACE
   1799  *	-FDT_ERR_BADLAYOUT
   1800  *      -FDT_ERR_BADMAGIC,
   1801  *	-FDT_ERR_BADVERSION,
   1802  *	-FDT_ERR_BADSTATE,
   1803  *	-FDT_ERR_BADSTRUCTURE,
   1804  *	-FDT_ERR_TRUNCATED, standard meanings.
   1805  */
   1806 int fdt_add_subnode(void *fdt, int parentoffset, const char *name);
   1807 
   1808 /**
   1809  * fdt_del_node - delete a node (subtree)
   1810  * @fdt: pointer to the device tree blob
   1811  * @nodeoffset: offset of the node to nop
   1812  *
   1813  * fdt_del_node() will remove the given node, including all its
   1814  * subnodes if any, from the blob.
   1815  *
   1816  * This function will delete data from the blob, and will therefore
   1817  * change the offsets of some existing nodes.
   1818  *
   1819  * returns:
   1820  *	0, on success
   1821  *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
   1822  *	-FDT_ERR_BADLAYOUT,
   1823  *	-FDT_ERR_BADMAGIC,
   1824  *	-FDT_ERR_BADVERSION,
   1825  *	-FDT_ERR_BADSTATE,
   1826  *	-FDT_ERR_BADSTRUCTURE,
   1827  *	-FDT_ERR_TRUNCATED, standard meanings
   1828  */
   1829 int fdt_del_node(void *fdt, int nodeoffset);
   1830 
   1831 /**
   1832  * fdt_overlay_apply - Applies a DT overlay on a base DT
   1833  * @fdt: pointer to the base device tree blob
   1834  * @fdto: pointer to the device tree overlay blob
   1835  *
   1836  * fdt_overlay_apply() will apply the given device tree overlay on the
   1837  * given base device tree.
   1838  *
   1839  * Expect the base device tree to be modified, even if the function
   1840  * returns an error.
   1841  *
   1842  * returns:
   1843  *	0, on success
   1844  *	-FDT_ERR_NOSPACE, there's not enough space in the base device tree
   1845  *	-FDT_ERR_NOTFOUND, the overlay points to some inexistant nodes or
   1846  *		properties in the base DT
   1847  *	-FDT_ERR_BADPHANDLE,
   1848  *	-FDT_ERR_BADOVERLAY,
   1849  *	-FDT_ERR_NOPHANDLES,
   1850  *	-FDT_ERR_INTERNAL,
   1851  *	-FDT_ERR_BADLAYOUT,
   1852  *	-FDT_ERR_BADMAGIC,
   1853  *	-FDT_ERR_BADOFFSET,
   1854  *	-FDT_ERR_BADPATH,
   1855  *	-FDT_ERR_BADVERSION,
   1856  *	-FDT_ERR_BADSTRUCTURE,
   1857  *	-FDT_ERR_BADSTATE,
   1858  *	-FDT_ERR_TRUNCATED, standard meanings
   1859  */
   1860 int fdt_overlay_apply(void *fdt, void *fdto);
   1861 
   1862 /**********************************************************************/
   1863 /* Debugging / informational functions                                */
   1864 /**********************************************************************/
   1865 
   1866 const char *fdt_strerror(int errval);
   1867 
   1868 #endif /* _LIBFDT_H */
   1869