include/libfdt.h

   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: Attemped 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          * value.  phandle values of 0 and -1 are not permitted. */
  84 #define FDT_ERR_BADSTATE        7
  85         /* FDT_ERR_BADSTATE: Function was passed an incomplete device
  86          * tree created by the sequential-write functions, which is
  87          * not sufficiently complete for the requested operation. */
  88
  89 /* Error codes: codes for bad device tree blobs */
  90 #define FDT_ERR_TRUNCATED       8
  91         /* FDT_ERR_TRUNCATED: Structure block of the given device tree
  92          * ends without an FDT_END tag. */
  93 #define FDT_ERR_BADMAGIC        9
  94         /* FDT_ERR_BADMAGIC: Given "device tree" appears not to be a
  95          * device tree at all - it is missing the flattened device
  96          * tree magic number. */
  97 #define FDT_ERR_BADVERSION      10
  98         /* FDT_ERR_BADVERSION: Given device tree has a version which
  99          * can't be handled by the requested operation.  For
 100          * read-write functions, this may mean that fdt_open_into() is
 101          * required to convert the tree to the expected version. */
 102 #define FDT_ERR_BADSTRUCTURE    11
 103         /* FDT_ERR_BADSTRUCTURE: Given device tree has a corrupt
 104          * structure block or other serious error (e.g. misnested
 105          * nodes, or subnodes preceding properties). */
 106 #define FDT_ERR_BADLAYOUT       12
 107         /* FDT_ERR_BADLAYOUT: For read-write functions, the given
 108          * device tree has it's sub-blocks in an order that the
 109          * function can't handle (memory reserve map, then structure,
 110          * then strings).  Use fdt_open_into() to reorganize the tree
 111          * into a form suitable for the read-write operations. */
 112
 113 /* "Can't happen" error indicating a bug in libfdt */
 114 #define FDT_ERR_INTERNAL        13
 115         /* FDT_ERR_INTERNAL: libfdt has failed an internal assertion.
 116          * Should never be returned, if it is, it indicates a bug in
 117          * libfdt itself. */
 118
 119 #define FDT_ERR_MAX             13
 120
 121 /**********************************************************************/
 122 /* Low-level functions (you probably don't need these)                */
 123 /**********************************************************************/
 124
 125 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int checklen);
 126 static inline void *fdt_offset_ptr_w(void *fdt, int offset, int checklen)
 127 {
 128         return (void *)(uintptr_t)fdt_offset_ptr(fdt, offset, checklen);
 129 }
 130
 131 uint32_t fdt_next_tag(const void *fdt, int offset, int *nextoffset);
 132
 133 /**********************************************************************/
 134 /* Traversal functions                                                */
 135 /**********************************************************************/
 136
 137 int fdt_next_node(const void *fdt, int offset, int *depth);
 138
 139 /**********************************************************************/
 140 /* General functions                                                  */
 141 /**********************************************************************/
 142
 143 #define fdt_get_header(fdt, field) \
 144         (fdt32_to_cpu(((const struct fdt_header *)(fdt))->field))
 145 #define fdt_magic(fdt)                  (fdt_get_header(fdt, magic))
 146 #define fdt_totalsize(fdt)              (fdt_get_header(fdt, totalsize))
 147 #define fdt_off_dt_struct(fdt)          (fdt_get_header(fdt, off_dt_struct))
 148 #define fdt_off_dt_strings(fdt)         (fdt_get_header(fdt, off_dt_strings))
 149 #define fdt_off_mem_rsvmap(fdt)         (fdt_get_header(fdt, off_mem_rsvmap))
 150 #define fdt_version(fdt)                (fdt_get_header(fdt, version))
 151 #define fdt_last_comp_version(fdt)      (fdt_get_header(fdt, last_comp_version))
 152 #define fdt_boot_cpuid_phys(fdt)        (fdt_get_header(fdt, boot_cpuid_phys))
 153 #define fdt_size_dt_strings(fdt)        (fdt_get_header(fdt, size_dt_strings))
 154 #define fdt_size_dt_struct(fdt)         (fdt_get_header(fdt, size_dt_struct))
 155
 156 #define __fdt_set_hdr(name) \
 157         static inline void fdt_set_##name(void *fdt, uint32_t val) \
 158         { \
 159                 struct fdt_header *fdth = (struct fdt_header*)fdt; \
 160                 fdth->name = cpu_to_fdt32(val); \
 161         }
 162 __fdt_set_hdr(magic);
 163 __fdt_set_hdr(totalsize);
 164 __fdt_set_hdr(off_dt_struct);
 165 __fdt_set_hdr(off_dt_strings);
 166 __fdt_set_hdr(off_mem_rsvmap);
 167 __fdt_set_hdr(version);
 168 __fdt_set_hdr(last_comp_version);
 169 __fdt_set_hdr(boot_cpuid_phys);
 170 __fdt_set_hdr(size_dt_strings);
 171 __fdt_set_hdr(size_dt_struct);
 172 #undef __fdt_set_hdr
 173
 174 /**
 175  * fdt_check_header - sanity check a device tree or possible device tree
 176  * @fdt: pointer to data which might be a flattened device tree
 177  *
 178  * fdt_check_header() checks that the given buffer contains what
 179  * appears to be a flattened device tree with sane information in its
 180  * header.
 181  *
 182  * returns:
 183  *     0, if the buffer appears to contain a valid device tree
 184  *     -FDT_ERR_BADMAGIC,
 185  *     -FDT_ERR_BADVERSION,
 186  *     -FDT_ERR_BADSTATE, standard meanings, as above
 187  */
 188 int fdt_check_header(const void *fdt);
 189
 190 /**
 191  * fdt_move - move a device tree around in memory
 192  * @fdt: pointer to the device tree to move
 193  * @buf: pointer to memory where the device is to be moved
 194  * @bufsize: size of the memory space at buf
 195  *
 196  * fdt_move() relocates, if possible, the device tree blob located at
 197  * fdt to the buffer at buf of size bufsize.  The buffer may overlap
 198  * with the existing device tree blob at fdt.  Therefore,
 199  *     fdt_move(fdt, fdt, fdt_totalsize(fdt))
 200  * should always succeed.
 201  *
 202  * returns:
 203  *     0, on success
 204  *     -FDT_ERR_NOSPACE, bufsize is insufficient to contain the device tree
 205  *     -FDT_ERR_BADMAGIC,
 206  *     -FDT_ERR_BADVERSION,
 207  *     -FDT_ERR_BADSTATE, standard meanings
 208  */
 209 int fdt_move(const void *fdt, void *buf, int bufsize);
 210
 211 /**********************************************************************/
 212 /* Read-only functions                                                */
 213 /**********************************************************************/
 214
 215 /**
 216  * fdt_string - retrieve a string from the strings block of a device tree
 217  * @fdt: pointer to the device tree blob
 218  * @stroffset: offset of the string within the strings block (native endian)
 219  *
 220  * fdt_string() retrieves a pointer to a single string from the
 221  * strings block of the device tree blob at fdt.
 222  *
 223  * returns:
 224  *     a pointer to the string, on success
 225  *     NULL, if stroffset is out of bounds
 226  */
 227 const char *fdt_string(const void *fdt, int stroffset);
 228
 229 /**
 230  * fdt_num_mem_rsv - retrieve the number of memory reserve map entries
 231  * @fdt: pointer to the device tree blob
 232  *
 233  * Returns the number of entries in the device tree blob's memory
 234  * reservation map.  This does not include the terminating 0,0 entry
 235  * or any other (0,0) entries reserved for expansion.
 236  *
 237  * returns:
 238  *     the number of entries
 239  */
 240 int fdt_num_mem_rsv(const void *fdt);
 241
 242 /**
 243  * fdt_get_mem_rsv - retrieve one memory reserve map entry
 244  * @fdt: pointer to the device tree blob
 245  * @address, @size: pointers to 64-bit variables
 246  *
 247  * On success, *address and *size will contain the address and size of
 248  * the n-th reserve map entry from the device tree blob, in
 249  * native-endian format.
 250  *
 251  * returns:
 252  *     0, on success
 253  *     -FDT_ERR_BADMAGIC,
 254  *     -FDT_ERR_BADVERSION,
 255  *     -FDT_ERR_BADSTATE, standard meanings
 256  */
 257 int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size);
 258
 259 /**
 260  * fdt_subnode_offset_namelen - find a subnode based on substring
 261  * @fdt: pointer to the device tree blob
 262  * @parentoffset: structure block offset of a node
 263  * @name: name of the subnode to locate
 264  * @namelen: number of characters of name to consider
 265  *
 266  * Identical to fdt_subnode_offset(), but only examine the first
 267  * namelen characters of name for matching the subnode name.  This is
 268  * useful for finding subnodes based on a portion of a larger string,
 269  * such as a full path.
 270  */
 271 int fdt_subnode_offset_namelen(const void *fdt, int parentoffset,
 272                                const char *name, int namelen);
 273 /**
 274  * fdt_subnode_offset - find a subnode of a given node
 275  * @fdt: pointer to the device tree blob
 276  * @parentoffset: structure block offset of a node
 277  * @name: name of the subnode to locate
 278  *
 279  * fdt_subnode_offset() finds a subnode of the node at structure block
 280  * offset parentoffset with the given name.  name may include a unit
 281  * address, in which case fdt_subnode_offset() will find the subnode
 282  * with that unit address, or the unit address may be omitted, in
 283  * which case fdt_subnode_offset() will find an arbitrary subnode
 284  * whose name excluding unit address matches the given name.
 285  *
 286  * returns:
 287  *      structure block offset of the requested subnode (>=0), on success
 288  *      -FDT_ERR_NOTFOUND, if the requested subnode does not exist
 289  *      -FDT_ERR_BADOFFSET, if parentoffset did not point to an FDT_BEGIN_NODE tag
 290  *      -FDT_ERR_BADMAGIC,
 291  *      -FDT_ERR_BADVERSION,
 292  *      -FDT_ERR_BADSTATE,
 293  *      -FDT_ERR_BADSTRUCTURE,
 294  *      -FDT_ERR_TRUNCATED, standard meanings.
 295  */
 296 int fdt_subnode_offset(const void *fdt, int parentoffset, const char *name);
 297
 298 /**
 299  * fdt_path_offset - find a tree node by its full path
 300  * @fdt: pointer to the device tree blob
 301  * @path: full path of the node to locate
 302  *
 303  * fdt_path_offset() finds a node of a given path in the device tree.
 304  * Each path component may omit the unit address portion, but the
 305  * results of this are undefined if any such path component is
 306  * ambiguous (that is if there are multiple nodes at the relevant
 307  * level matching the given component, differentiated only by unit
 308  * address).
 309  *
 310  * returns:
 311  *      structure block offset of the node with the requested path (>=0), on success
 312  *      -FDT_ERR_BADPATH, given path does not begin with '/' or is invalid
 313  *      -FDT_ERR_NOTFOUND, if the requested node does not exist
 314  *      -FDT_ERR_BADMAGIC,
 315  *      -FDT_ERR_BADVERSION,
 316  *      -FDT_ERR_BADSTATE,
 317  *      -FDT_ERR_BADSTRUCTURE,
 318  *      -FDT_ERR_TRUNCATED, standard meanings.
 319  */
 320 int fdt_path_offset(const void *fdt, const char *path);
 321
 322 /**
 323  * fdt_get_name - retrieve the name of a given node
 324  * @fdt: pointer to the device tree blob
 325  * @nodeoffset: structure block offset of the starting node
 326  * @lenp: pointer to an integer variable (will be overwritten) or NULL
 327  *
 328  * fdt_get_name() retrieves the name (including unit address) of the
 329  * device tree node at structure block offset nodeoffset.  If lenp is
 330  * non-NULL, the length of this name is also returned, in the integer
 331  * pointed to by lenp.
 332  *
 333  * returns:
 334  *      pointer to the node's name, on success
 335  *              If lenp is non-NULL, *lenp contains the length of that name (>=0)
 336  *      NULL, on error
 337  *              if lenp is non-NULL *lenp contains an error code (<0):
 338  *              -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
 339  *              -FDT_ERR_BADMAGIC,
 340  *              -FDT_ERR_BADVERSION,
 341  *              -FDT_ERR_BADSTATE, standard meanings
 342  */
 343 const char *fdt_get_name(const void *fdt, int nodeoffset, int *lenp);
 344
 345 /**
 346  * fdt_get_property_namelen - find a property based on substring
 347  * @fdt: pointer to the device tree blob
 348  * @nodeoffset: offset of the node whose property to find
 349  * @name: name of the property to find
 350  * @namelen: number of characters of name to consider
 351  * @lenp: pointer to an integer variable (will be overwritten) or NULL
 352  *
 353  * Identical to fdt_get_property_namelen(), but only examine the first
 354  * namelen characters of name for matching the property name.
 355  */
 356 const struct fdt_property *fdt_get_property_namelen(const void *fdt,
 357                                                     int nodeoffset,
 358                                                     const char *name,
 359                                                     int namelen, int *lenp);
 360
 361 /**
 362  * fdt_get_property - find a given property in a given node
 363  * @fdt: pointer to the device tree blob
 364  * @nodeoffset: offset of the node whose property to find
 365  * @name: name of the property to find
 366  * @lenp: pointer to an integer variable (will be overwritten) or NULL
 367  *
 368  * fdt_get_property() retrieves a pointer to the fdt_property
 369  * structure within the device tree blob corresponding to the property
 370  * named 'name' of the node at offset nodeoffset.  If lenp is
 371  * non-NULL, the length of the property value is also returned, in the
 372  * integer pointed to by lenp.
 373  *
 374  * returns:
 375  *      pointer to the structure representing the property
 376  *              if lenp is non-NULL, *lenp contains the length of the property
 377  *              value (>=0)
 378  *      NULL, on error
 379  *              if lenp is non-NULL, *lenp contains an error code (<0):
 380  *              -FDT_ERR_NOTFOUND, node does not have named property
 381  *              -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
 382  *              -FDT_ERR_BADMAGIC,
 383  *              -FDT_ERR_BADVERSION,
 384  *              -FDT_ERR_BADSTATE,
 385  *              -FDT_ERR_BADSTRUCTURE,
 386  *              -FDT_ERR_TRUNCATED, standard meanings
 387  */
 388 const struct fdt_property *fdt_get_property(const void *fdt, int nodeoffset,
 389                                             const char *name, int *lenp);
 390 static inline struct fdt_property *fdt_get_property_w(void *fdt, int nodeoffset,
 391                                                       const char *name,
 392                                                       int *lenp)
 393 {
 394         return (struct fdt_property *)(uintptr_t)
 395                 fdt_get_property(fdt, nodeoffset, name, lenp);
 396 }
 397
 398 /**
 399  * fdt_getprop_namelen - get property value based on substring
 400  * @fdt: pointer to the device tree blob
 401  * @nodeoffset: offset of the node whose property to find
 402  * @name: name of the property to find
 403  * @namelen: number of characters of name to consider
 404  * @lenp: pointer to an integer variable (will be overwritten) or NULL
 405  *
 406  * Identical to fdt_getprop(), but only examine the first namelen
 407  * characters of name for matching the property name.
 408  */
 409 const void *fdt_getprop_namelen(const void *fdt, int nodeoffset,
 410                                 const char *name, int namelen, int *lenp);
 411
 412 /**
 413  * fdt_getprop - retrieve the value of a given property
 414  * @fdt: pointer to the device tree blob
 415  * @nodeoffset: offset of the node whose property to find
 416  * @name: name of the property to find
 417  * @lenp: pointer to an integer variable (will be overwritten) or NULL
 418  *
 419  * fdt_getprop() retrieves a pointer to the value of the property
 420  * named 'name' of the node at offset nodeoffset (this will be a
 421  * pointer to within the device blob itself, not a copy of the value).
 422  * If lenp is non-NULL, the length of the property value is also
 423  * returned, in the integer pointed to by lenp.
 424  *
 425  * returns:
 426  *      pointer to the property's value
 427  *              if lenp is non-NULL, *lenp contains the length of the property
 428  *              value (>=0)
 429  *      NULL, on error
 430  *              if lenp is non-NULL, *lenp contains an error code (<0):
 431  *              -FDT_ERR_NOTFOUND, node does not have named property
 432  *              -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
 433  *              -FDT_ERR_BADMAGIC,
 434  *              -FDT_ERR_BADVERSION,
 435  *              -FDT_ERR_BADSTATE,
 436  *              -FDT_ERR_BADSTRUCTURE,
 437  *              -FDT_ERR_TRUNCATED, standard meanings
 438  */
 439 const void *fdt_getprop(const void *fdt, int nodeoffset,
 440                         const char *name, int *lenp);
 441 static inline void *fdt_getprop_w(void *fdt, int nodeoffset,
 442                                   const char *name, int *lenp)
 443 {
 444         return (void *)(uintptr_t)fdt_getprop(fdt, nodeoffset, name, lenp);
 445 }
 446
 447 /**
 448  * fdt_get_phandle - retrieve the phandle of a given node
 449  * @fdt: pointer to the device tree blob
 450  * @nodeoffset: structure block offset of the node
 451  *
 452  * fdt_get_phandle() retrieves the phandle of the device tree node at
 453  * structure block offset nodeoffset.
 454  *
 455  * returns:
 456  *      the phandle of the node at nodeoffset, on success (!= 0, != -1)
 457  *      0, if the node has no phandle, or another error occurs
 458  */
 459 uint32_t fdt_get_phandle(const void *fdt, int nodeoffset);
 460
 461 /**
 462  * fdt_get_alias_namelen - get alias based on substring
 463  * @fdt: pointer to the device tree blob
 464  * @name: name of the alias th look up
 465  * @namelen: number of characters of name to consider
 466  *
 467  * Identical to fdt_get_alias(), but only examine the first namelen
 468  * characters of name for matching the alias name.
 469  */
 470 const char *fdt_get_alias_namelen(const void *fdt,
 471                                   const char *name, int namelen);
 472
 473 /**
 474  * fdt_get_alias - retreive the path referenced by a given alias
 475  * @fdt: pointer to the device tree blob
 476  * @name: name of the alias th look up
 477  *
 478  * fdt_get_alias() retrieves the value of a given alias.  That is, the
 479  * value of the property named 'name' in the node /aliases.
 480  *
 481  * returns:
 482  *      a pointer to the expansion of the alias named 'name', of it exists
 483  *      NULL, if the given alias or the /aliases node does not exist
 484  */
 485 const char *fdt_get_alias(const void *fdt, const char *name);
 486
 487 /**
 488  * fdt_get_path - determine the full path of a node
 489  * @fdt: pointer to the device tree blob
 490  * @nodeoffset: offset of the node whose path to find
 491  * @buf: character buffer to contain the returned path (will be overwritten)
 492  * @buflen: size of the character buffer at buf
 493  *
 494  * fdt_get_path() computes the full path of the node at offset
 495  * nodeoffset, and records that path in the buffer at buf.
 496  *
 497  * NOTE: This function is expensive, as it must scan the device tree
 498  * structure from the start to nodeoffset.
 499  *
 500  * returns:
 501  *      0, on success
 502  *              buf contains the absolute path of the node at
 503  *              nodeoffset, as a NUL-terminated string.
 504  *      -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
 505  *      -FDT_ERR_NOSPACE, the path of the given node is longer than (bufsize-1)
 506  *              characters and will not fit in the given buffer.
 507  *      -FDT_ERR_BADMAGIC,
 508  *      -FDT_ERR_BADVERSION,
 509  *      -FDT_ERR_BADSTATE,
 510  *      -FDT_ERR_BADSTRUCTURE, standard meanings
 511  */
 512 int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen);
 513
 514 /**
 515  * fdt_supernode_atdepth_offset - find a specific ancestor of a node
 516  * @fdt: pointer to the device tree blob
 517  * @nodeoffset: offset of the node whose parent to find
 518  * @supernodedepth: depth of the ancestor to find
 519  * @nodedepth: pointer to an integer variable (will be overwritten) or NULL
 520  *
 521  * fdt_supernode_atdepth_offset() finds an ancestor of the given node
 522  * at a specific depth from the root (where the root itself has depth
 523  * 0, its immediate subnodes depth 1 and so forth).  So
 524  *      fdt_supernode_atdepth_offset(fdt, nodeoffset, 0, NULL);
 525  * will always return 0, the offset of the root node.  If the node at
 526  * nodeoffset has depth D, then:
 527  *      fdt_supernode_atdepth_offset(fdt, nodeoffset, D, NULL);
 528  * will return nodeoffset itself.
 529  *
 530  * NOTE: This function is expensive, as it must scan the device tree
 531  * structure from the start to nodeoffset.
 532  *
 533  * returns:
 534
 535  *      structure block offset of the node at node offset's ancestor
 536  *              of depth supernodedepth (>=0), on success
 537  *      -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
 538 *       -FDT_ERR_NOTFOUND, supernodedepth was greater than the depth of nodeoffset
 539  *      -FDT_ERR_BADMAGIC,
 540  *      -FDT_ERR_BADVERSION,
 541  *      -FDT_ERR_BADSTATE,
 542  *      -FDT_ERR_BADSTRUCTURE, standard meanings
 543  */
 544 int fdt_supernode_atdepth_offset(const void *fdt, int nodeoffset,
 545                                  int supernodedepth, int *nodedepth);
 546
 547 /**
 548  * fdt_node_depth - find the depth of a given node
 549  * @fdt: pointer to the device tree blob
 550  * @nodeoffset: offset of the node whose parent to find
 551  *
 552  * fdt_node_depth() finds the depth of a given node.  The root node
 553  * has depth 0, its immediate subnodes depth 1 and so forth.
 554  *
 555  * NOTE: This function is expensive, as it must scan the device tree
 556  * structure from the start to nodeoffset.
 557  *
 558  * returns:
 559  *      depth of the node at nodeoffset (>=0), on success
 560  *      -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
 561  *      -FDT_ERR_BADMAGIC,
 562  *      -FDT_ERR_BADVERSION,
 563  *      -FDT_ERR_BADSTATE,
 564  *      -FDT_ERR_BADSTRUCTURE, standard meanings
 565  */
 566 int fdt_node_depth(const void *fdt, int nodeoffset);
 567
 568 /**
 569  * fdt_parent_offset - find the parent of a given node
 570  * @fdt: pointer to the device tree blob
 571  * @nodeoffset: offset of the node whose parent to find
 572  *
 573  * fdt_parent_offset() locates the parent node of a given node (that
 574  * is, it finds the offset of the node which contains the node at
 575  * nodeoffset as a subnode).
 576  *
 577  * NOTE: This function is expensive, as it must scan the device tree
 578  * structure from the start to nodeoffset, *twice*.
 579  *
 580  * returns:
 581  *      structure block offset of the parent of the node at nodeoffset
 582  *              (>=0), on success
 583  *      -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
 584  *      -FDT_ERR_BADMAGIC,
 585  *      -FDT_ERR_BADVERSION,
 586  *      -FDT_ERR_BADSTATE,
 587  *      -FDT_ERR_BADSTRUCTURE, standard meanings
 588  */
 589 int fdt_parent_offset(const void *fdt, int nodeoffset);
 590
 591 /**
 592  * fdt_node_offset_by_prop_value - find nodes with a given property value
 593  * @fdt: pointer to the device tree blob
 594  * @startoffset: only find nodes after this offset
 595  * @propname: property name to check
 596  * @propval: property value to search for
 597  * @proplen: length of the value in propval
 598  *
 599  * fdt_node_offset_by_prop_value() returns the offset of the first
 600  * node after startoffset, which has a property named propname whose
 601  * value is of length proplen and has value equal to propval; or if
 602  * startoffset is -1, the very first such node in the tree.
 603  *
 604  * To iterate through all nodes matching the criterion, the following
 605  * idiom can be used:
 606  *      offset = fdt_node_offset_by_prop_value(fdt, -1, propname,
 607  *                                             propval, proplen);
 608  *      while (offset != -FDT_ERR_NOTFOUND) {
 609  *              ... other code here ...
 610  *              offset = fdt_node_offset_by_prop_value(fdt, offset, propname,
 611  *                                                     propval, proplen);
 612  *      }
 613  *
 614  * Note the -1 in the first call to the function, if 0 is used here
 615  * instead, the function will never locate the root node, even if it
 616  * matches the criterion.
 617  *
 618  * returns:
 619  *      structure block offset of the located node (>= 0, >startoffset),
 620  *               on success
 621  *      -FDT_ERR_NOTFOUND, no node matching the criterion exists in the
 622  *              tree after startoffset
 623  *      -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
 624  *      -FDT_ERR_BADMAGIC,
 625  *      -FDT_ERR_BADVERSION,
 626  *      -FDT_ERR_BADSTATE,
 627  *      -FDT_ERR_BADSTRUCTURE, standard meanings
 628  */
 629 int fdt_node_offset_by_prop_value(const void *fdt, int startoffset,
 630                                   const char *propname,
 631                                   const void *propval, int proplen);
 632
 633 /**
 634  * fdt_node_offset_by_phandle - find the node with a given phandle
 635  * @fdt: pointer to the device tree blob
 636  * @phandle: phandle value
 637  *
 638  * fdt_node_offset_by_phandle() returns the offset of the node
 639  * which has the given phandle value.  If there is more than one node
 640  * in the tree with the given phandle (an invalid tree), results are
 641  * undefined.
 642  *
 643  * returns:
 644  *      structure block offset of the located node (>= 0), on success
 645  *      -FDT_ERR_NOTFOUND, no node with that phandle exists
 646  *      -FDT_ERR_BADPHANDLE, given phandle value was invalid (0 or -1)
 647  *      -FDT_ERR_BADMAGIC,
 648  *      -FDT_ERR_BADVERSION,
 649  *      -FDT_ERR_BADSTATE,
 650  *      -FDT_ERR_BADSTRUCTURE, standard meanings
 651  */
 652 int fdt_node_offset_by_phandle(const void *fdt, uint32_t phandle);
 653
 654 /**
 655  * fdt_node_check_compatible: check a node's compatible property
 656  * @fdt: pointer to the device tree blob
 657  * @nodeoffset: offset of a tree node
 658  * @compatible: string to match against
 659  *
 660  *
 661  * fdt_node_check_compatible() returns 0 if the given node contains a
 662  * 'compatible' property with the given string as one of its elements,
 663  * it returns non-zero otherwise, or on error.
 664  *
 665  * returns:
 666  *      0, if the node has a 'compatible' property listing the given string
 667  *      1, if the node has a 'compatible' property, but it does not list
 668  *              the given string
 669  *      -FDT_ERR_NOTFOUND, if the given node has no 'compatible' property
 670  *      -FDT_ERR_BADOFFSET, if nodeoffset does not refer to a BEGIN_NODE tag
 671  *      -FDT_ERR_BADMAGIC,
 672  *      -FDT_ERR_BADVERSION,
 673  *      -FDT_ERR_BADSTATE,
 674  *      -FDT_ERR_BADSTRUCTURE, standard meanings
 675  */
 676 int fdt_node_check_compatible(const void *fdt, int nodeoffset,
 677                               const char *compatible);
 678
 679 /**
 680  * fdt_node_offset_by_compatible - find nodes with a given 'compatible' value
 681  * @fdt: pointer to the device tree blob
 682  * @startoffset: only find nodes after this offset
 683  * @compatible: 'compatible' string to match against
 684  *
 685  * fdt_node_offset_by_compatible() returns the offset of the first
 686  * node after startoffset, which has a 'compatible' property which
 687  * lists the given compatible string; or if startoffset is -1, the
 688  * very first such node in the tree.
 689  *
 690  * To iterate through all nodes matching the criterion, the following
 691  * idiom can be used:
 692  *      offset = fdt_node_offset_by_compatible(fdt, -1, compatible);
 693  *      while (offset != -FDT_ERR_NOTFOUND) {
 694  *              ... other code here ...
 695  *              offset = fdt_node_offset_by_compatible(fdt, offset, compatible);
 696  *      }
 697  *
 698  * Note the -1 in the first call to the function, if 0 is used here
 699  * instead, the function will never locate the root node, even if it
 700  * matches the criterion.
 701  *
 702  * returns:
 703  *      structure block offset of the located node (>= 0, >startoffset),
 704  *               on success
 705  *      -FDT_ERR_NOTFOUND, no node matching the criterion exists in the
 706  *              tree after startoffset
 707  *      -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
 708  *      -FDT_ERR_BADMAGIC,
 709  *      -FDT_ERR_BADVERSION,
 710  *      -FDT_ERR_BADSTATE,
 711  *      -FDT_ERR_BADSTRUCTURE, standard meanings
 712  */
 713 int fdt_node_offset_by_compatible(const void *fdt, int startoffset,
 714                                   const char *compatible);
 715
 716 /**********************************************************************/
 717 /* Write-in-place functions                                           */
 718 /**********************************************************************/
 719
 720 /**
 721  * fdt_setprop_inplace - change a property's value, but not its size
 722  * @fdt: pointer to the device tree blob
 723  * @nodeoffset: offset of the node whose property to change
 724  * @name: name of the property to change
 725  * @val: pointer to data to replace the property value with
 726  * @len: length of the property value
 727  *
 728  * fdt_setprop_inplace() replaces the value of a given property with
 729  * the data in val, of length len.  This function cannot change the
 730  * size of a property, and so will only work if len is equal to the
 731  * current length of the property.
 732  *
 733  * This function will alter only the bytes in the blob which contain
 734  * the given property value, and will not alter or move any other part
 735  * of the tree.
 736  *
 737  * returns:
 738  *      0, on success
 739  *      -FDT_ERR_NOSPACE, if len is not equal to the property's current length
 740  *      -FDT_ERR_NOTFOUND, node does not have the named property
 741  *      -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
 742  *      -FDT_ERR_BADMAGIC,
 743  *      -FDT_ERR_BADVERSION,
 744  *      -FDT_ERR_BADSTATE,
 745  *      -FDT_ERR_BADSTRUCTURE,
 746  *      -FDT_ERR_TRUNCATED, standard meanings
 747  */
 748 int fdt_setprop_inplace(void *fdt, int nodeoffset, const char *name,
 749                         const void *val, int len);
 750
 751 /**
 752  * fdt_setprop_inplace_cell - change the value of a single-cell property
 753  * @fdt: pointer to the device tree blob
 754  * @nodeoffset: offset of the node whose property to change
 755  * @name: name of the property to change
 756  * @val: cell (32-bit integer) value to replace the property with
 757  *
 758  * fdt_setprop_inplace_cell() replaces the value of a given property
 759  * with the 32-bit integer cell value in val, converting val to
 760  * big-endian if necessary.  This function cannot change the size of a
 761  * property, and so will only work if the property already exists and
 762  * has length 4.
 763  *
 764  * This function will alter only the bytes in the blob which contain
 765  * the given property value, and will not alter or move any other part
 766  * of the tree.
 767  *
 768  * returns:
 769  *      0, on success
 770  *      -FDT_ERR_NOSPACE, if the property's length is not equal to 4
 771   *     -FDT_ERR_NOTFOUND, node does not have the named property
 772  *      -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
 773  *      -FDT_ERR_BADMAGIC,
 774  *      -FDT_ERR_BADVERSION,
 775  *      -FDT_ERR_BADSTATE,
 776  *      -FDT_ERR_BADSTRUCTURE,
 777  *      -FDT_ERR_TRUNCATED, standard meanings
 778  */
 779 static inline int fdt_setprop_inplace_cell(void *fdt, int nodeoffset,
 780                                            const char *name, uint32_t val)
 781 {
 782         val = cpu_to_fdt32(val);
 783         return fdt_setprop_inplace(fdt, nodeoffset, name, &val, sizeof(val));
 784 }
 785
 786 /**
 787  * fdt_nop_property - replace a property with nop tags
 788  * @fdt: pointer to the device tree blob
 789  * @nodeoffset: offset of the node whose property to nop
 790  * @name: name of the property to nop
 791  *
 792  * fdt_nop_property() will replace a given property's representation
 793  * in the blob with FDT_NOP tags, effectively removing it from the
 794  * tree.
 795  *
 796  * This function will alter only the bytes in the blob which contain
 797  * the property, and will not alter or move any other part of the
 798  * tree.
 799  *
 800  * returns:
 801  *      0, on success
 802  *      -FDT_ERR_NOTFOUND, node does not have the named property
 803  *      -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
 804  *      -FDT_ERR_BADMAGIC,
 805  *      -FDT_ERR_BADVERSION,
 806  *      -FDT_ERR_BADSTATE,
 807  *      -FDT_ERR_BADSTRUCTURE,
 808  *      -FDT_ERR_TRUNCATED, standard meanings
 809  */
 810 int fdt_nop_property(void *fdt, int nodeoffset, const char *name);
 811
 812 /**
 813  * fdt_nop_node - replace a node (subtree) with nop tags
 814  * @fdt: pointer to the device tree blob
 815  * @nodeoffset: offset of the node to nop
 816  *
 817  * fdt_nop_node() will replace a given node's representation in the
 818  * blob, including all its subnodes, if any, with FDT_NOP tags,
 819  * effectively removing it from the tree.
 820  *
 821  * This function will alter only the bytes in the blob which contain
 822  * the node and its properties and subnodes, and will not alter or
 823  * move any other part of the tree.
 824  *
 825  * returns:
 826  *      0, on success
 827  *      -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
 828  *      -FDT_ERR_BADMAGIC,
 829  *      -FDT_ERR_BADVERSION,
 830  *      -FDT_ERR_BADSTATE,
 831  *      -FDT_ERR_BADSTRUCTURE,
 832  *      -FDT_ERR_TRUNCATED, standard meanings
 833  */
 834 int fdt_nop_node(void *fdt, int nodeoffset);
 835
 836 /**********************************************************************/
 837 /* Sequential write functions                                         */
 838 /**********************************************************************/
 839
 840 int fdt_create(void *buf, int bufsize);
 841 int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size);
 842 int fdt_finish_reservemap(void *fdt);
 843 int fdt_begin_node(void *fdt, const char *name);
 844 int fdt_property(void *fdt, const char *name, const void *val, int len);
 845 static inline int fdt_property_cell(void *fdt, const char *name, uint32_t val)
 846 {
 847         val = cpu_to_fdt32(val);
 848         return fdt_property(fdt, name, &val, sizeof(val));
 849 }
 850 #define fdt_property_string(fdt, name, str) \
 851         fdt_property(fdt, name, str, strlen(str)+1)
 852 int fdt_end_node(void *fdt);
 853 int fdt_finish(void *fdt);
 854
 855 /**********************************************************************/
 856 /* Read-write functions                                               */
 857 /**********************************************************************/
 858
 859 int fdt_open_into(const void *fdt, void *buf, int bufsize);
 860 int fdt_pack(void *fdt);
 861
 862 /**
 863  * fdt_add_mem_rsv - add one memory reserve map entry
 864  * @fdt: pointer to the device tree blob
 865  * @address, @size: 64-bit values (native endian)
 866  *
 867  * Adds a reserve map entry to the given blob reserving a region at
 868  * address address of length size.
 869  *
 870  * This function will insert data into the reserve map and will
 871  * therefore change the indexes of some entries in the table.
 872  *
 873  * returns:
 874  *      0, on success
 875  *      -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
 876  *              contain the new reservation entry
 877  *      -FDT_ERR_BADMAGIC,
 878  *      -FDT_ERR_BADVERSION,
 879  *      -FDT_ERR_BADSTATE,
 880  *      -FDT_ERR_BADSTRUCTURE,
 881  *      -FDT_ERR_BADLAYOUT,
 882  *      -FDT_ERR_TRUNCATED, standard meanings
 883  */
 884 int fdt_add_mem_rsv(void *fdt, uint64_t address, uint64_t size);
 885
 886 /**
 887  * fdt_del_mem_rsv - remove a memory reserve map entry
 888  * @fdt: pointer to the device tree blob
 889  * @n: entry to remove
 890  *
 891  * fdt_del_mem_rsv() removes the n-th memory reserve map entry from
 892  * the blob.
 893  *
 894  * This function will delete data from the reservation table and will
 895  * therefore change the indexes of some entries in the table.
 896  *
 897  * returns:
 898  *      0, on success
 899  *      -FDT_ERR_NOTFOUND, there is no entry of the given index (i.e. there
 900  *              are less than n+1 reserve map entries)
 901  *      -FDT_ERR_BADMAGIC,
 902  *      -FDT_ERR_BADVERSION,
 903  *      -FDT_ERR_BADSTATE,
 904  *      -FDT_ERR_BADSTRUCTURE,
 905  *      -FDT_ERR_BADLAYOUT,
 906  *      -FDT_ERR_TRUNCATED, standard meanings
 907  */
 908 int fdt_del_mem_rsv(void *fdt, int n);
 909
 910 /**
 911  * fdt_set_name - change the name of a given node
 912  * @fdt: pointer to the device tree blob
 913  * @nodeoffset: structure block offset of a node
 914  * @name: name to give the node
 915  *
 916  * fdt_set_name() replaces the name (including unit address, if any)
 917  * of the given node with the given string.  NOTE: this function can't
 918  * efficiently check if the new name is unique amongst the given
 919  * node's siblings; results are undefined if this function is invoked
 920  * with a name equal to one of the given node's siblings.
 921  *
 922  * This function may insert or delete data from the blob, and will
 923  * therefore change the offsets of some existing nodes.
 924  *
 925  * returns:
 926  *      0, on success
 927  *      -FDT_ERR_NOSPACE, there is insufficient free space in the blob
 928  *              to contain the new name
 929  *      -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
 930  *      -FDT_ERR_BADMAGIC,
 931  *      -FDT_ERR_BADVERSION,
 932  *      -FDT_ERR_BADSTATE, standard meanings
 933  */
 934 int fdt_set_name(void *fdt, int nodeoffset, const char *name);
 935
 936 /**
 937  * fdt_setprop - create or change a property
 938  * @fdt: pointer to the device tree blob
 939  * @nodeoffset: offset of the node whose property to change
 940  * @name: name of the property to change
 941  * @val: pointer to data to set the property value to
 942  * @len: length of the property value
 943  *
 944  * fdt_setprop() sets the value of the named property in the given
 945  * node to the given value and length, creating the property if it
 946  * does not already exist.
 947  *
 948  * This function may insert or delete data from the blob, and will
 949  * therefore change the offsets of some existing nodes.
 950  *
 951  * returns:
 952  *      0, on success
 953  *      -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
 954  *              contain the new property value
 955  *      -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
 956  *      -FDT_ERR_BADLAYOUT,
 957  *      -FDT_ERR_BADMAGIC,
 958  *      -FDT_ERR_BADVERSION,
 959  *      -FDT_ERR_BADSTATE,
 960  *      -FDT_ERR_BADSTRUCTURE,
 961  *      -FDT_ERR_BADLAYOUT,
 962  *      -FDT_ERR_TRUNCATED, standard meanings
 963  */
 964 int fdt_setprop(void *fdt, int nodeoffset, const char *name,
 965                 const void *val, int len);
 966
 967 /**
 968  * fdt_setprop_cell - set a property to a single cell value
 969  * @fdt: pointer to the device tree blob
 970  * @nodeoffset: offset of the node whose property to change
 971  * @name: name of the property to change
 972  * @val: 32-bit integer value for the property (native endian)
 973  *
 974  * fdt_setprop_cell() sets the value of the named property in the
 975  * given node to the given cell value (converting to big-endian if
 976  * necessary), or creates a new property with that value if it does
 977  * not already exist.
 978  *
 979  * This function may insert or delete data from the blob, and will
 980  * therefore change the offsets of some existing nodes.
 981  *
 982  * returns:
 983  *      0, on success
 984  *      -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
 985  *              contain the new property value
 986  *      -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
 987  *      -FDT_ERR_BADLAYOUT,
 988  *      -FDT_ERR_BADMAGIC,
 989  *      -FDT_ERR_BADVERSION,
 990  *      -FDT_ERR_BADSTATE,
 991  *      -FDT_ERR_BADSTRUCTURE,
 992  *      -FDT_ERR_BADLAYOUT,
 993  *      -FDT_ERR_TRUNCATED, standard meanings
 994  */
 995 static inline int fdt_setprop_cell(void *fdt, int nodeoffset, const char *name,
 996                                    uint32_t val)
 997 {
 998         val = cpu_to_fdt32(val);
 999         return fdt_setprop(fdt, nodeoffset, name, &val, sizeof(val));
1000 }
1001
1002 /**
1003  * fdt_setprop_string - set a property to a string value
1004  * @fdt: pointer to the device tree blob
1005  * @nodeoffset: offset of the node whose property to change
1006  * @name: name of the property to change
1007  * @str: string value for the property
1008  *
1009  * fdt_setprop_string() sets the value of the named property in the
1010  * given node to the given string value (using the length of the
1011  * string to determine the new length of the property), or creates a
1012  * new property with that value if it does not already exist.
1013  *
1014  * This function may insert or delete data from the blob, and will
1015  * therefore change the offsets of some existing nodes.
1016  *
1017  * returns:
1018  *      0, on success
1019  *      -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1020  *              contain the new property value
1021  *      -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1022  *      -FDT_ERR_BADLAYOUT,
1023  *      -FDT_ERR_BADMAGIC,
1024  *      -FDT_ERR_BADVERSION,
1025  *      -FDT_ERR_BADSTATE,
1026  *      -FDT_ERR_BADSTRUCTURE,
1027  *      -FDT_ERR_BADLAYOUT,
1028  *      -FDT_ERR_TRUNCATED, standard meanings
1029  */
1030 #define fdt_setprop_string(fdt, nodeoffset, name, str) \
1031         fdt_setprop((fdt), (nodeoffset), (name), (str), strlen(str)+1)
1032
1033 /**
1034  * fdt_delprop - delete a property
1035  * @fdt: pointer to the device tree blob
1036  * @nodeoffset: offset of the node whose property to nop
1037  * @name: name of the property to nop
1038  *
1039  * fdt_del_property() will delete the given property.
1040  *
1041  * This function will delete data from the blob, and will therefore
1042  * change the offsets of some existing nodes.
1043  *
1044  * returns:
1045  *      0, on success
1046  *      -FDT_ERR_NOTFOUND, node does not have the named property
1047  *      -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1048  *      -FDT_ERR_BADLAYOUT,
1049  *      -FDT_ERR_BADMAGIC,
1050  *      -FDT_ERR_BADVERSION,
1051  *      -FDT_ERR_BADSTATE,
1052  *      -FDT_ERR_BADSTRUCTURE,
1053  *      -FDT_ERR_TRUNCATED, standard meanings
1054  */
1055 int fdt_delprop(void *fdt, int nodeoffset, const char *name);
1056
1057 /**
1058  * fdt_add_subnode_namelen - creates a new node based on substring
1059  * @fdt: pointer to the device tree blob
1060  * @parentoffset: structure block offset of a node
1061  * @name: name of the subnode to locate
1062  * @namelen: number of characters of name to consider
1063  *
1064  * Identical to fdt_add_subnode(), but use only the first namelen
1065  * characters of name as the name of the new node.  This is useful for
1066  * creating subnodes based on a portion of a larger string, such as a
1067  * full path.
1068  */
1069 int fdt_add_subnode_namelen(void *fdt, int parentoffset,
1070                             const char *name, int namelen);
1071
1072 /**
1073  * fdt_add_subnode - creates a new node
1074  * @fdt: pointer to the device tree blob
1075  * @parentoffset: structure block offset of a node
1076  * @name: name of the subnode to locate
1077  *
1078  * fdt_add_subnode() creates a new node as a subnode of the node at
1079  * structure block offset parentoffset, with the given name (which
1080  * should include the unit address, if any).
1081  *
1082  * This function will insert data into the blob, and will therefore
1083  * change the offsets of some existing nodes.
1084
1085  * returns:
1086  *      structure block offset of the created nodeequested subnode (>=0), on success
1087  *      -FDT_ERR_NOTFOUND, if the requested subnode does not exist
1088  *      -FDT_ERR_BADOFFSET, if parentoffset did not point to an FDT_BEGIN_NODE tag
1089  *      -FDT_ERR_EXISTS, if the node at parentoffset already has a subnode of
1090  *              the given name
1091  *      -FDT_ERR_NOSPACE, if there is insufficient free space in the
1092  *              blob to contain the new node
1093  *      -FDT_ERR_NOSPACE
1094  *      -FDT_ERR_BADLAYOUT
1095  *      -FDT_ERR_BADMAGIC,
1096  *      -FDT_ERR_BADVERSION,
1097  *      -FDT_ERR_BADSTATE,
1098  *      -FDT_ERR_BADSTRUCTURE,
1099  *      -FDT_ERR_TRUNCATED, standard meanings.
1100  */
1101 int fdt_add_subnode(void *fdt, int parentoffset, const char *name);
1102
1103 /**
1104  * fdt_del_node - delete a node (subtree)
1105  * @fdt: pointer to the device tree blob
1106  * @nodeoffset: offset of the node to nop
1107  *
1108  * fdt_del_node() will remove the given node, including all its
1109  * subnodes if any, from the blob.
1110  *
1111  * This function will delete data from the blob, and will therefore
1112  * change the offsets of some existing nodes.
1113  *
1114  * returns:
1115  *      0, on success
1116  *      -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1117  *      -FDT_ERR_BADLAYOUT,
1118  *      -FDT_ERR_BADMAGIC,
1119  *      -FDT_ERR_BADVERSION,
1120  *      -FDT_ERR_BADSTATE,
1121  *      -FDT_ERR_BADSTRUCTURE,
1122  *      -FDT_ERR_TRUNCATED, standard meanings
1123  */
1124 int fdt_del_node(void *fdt, int nodeoffset);
1125
1126 /**********************************************************************/
1127 /* Debugging / informational functions                                */
1128 /**********************************************************************/
1129
1130 const char *fdt_strerror(int errval);
1131
1132 #endif /* _LIBFDT_H */