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0001 /* SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause) */
0002 #ifndef LIBFDT_H
0003 #define LIBFDT_H
0004 /*
0005  * libfdt - Flat Device Tree manipulation
0006  * Copyright (C) 2006 David Gibson, IBM Corporation.
0007  */
0008 
0009 #include <libfdt_env.h>
0010 #include <fdt.h>
0011 
0012 #ifdef __cplusplus
0013 extern "C" {
0014 #endif
0015 
0016 #define FDT_FIRST_SUPPORTED_VERSION 0x02
0017 #define FDT_LAST_COMPATIBLE_VERSION 0x10
0018 #define FDT_LAST_SUPPORTED_VERSION  0x11
0019 
0020 /* Error codes: informative error codes */
0021 #define FDT_ERR_NOTFOUND    1
0022     /* FDT_ERR_NOTFOUND: The requested node or property does not exist */
0023 #define FDT_ERR_EXISTS      2
0024     /* FDT_ERR_EXISTS: Attempted to create a node or property which
0025      * already exists */
0026 #define FDT_ERR_NOSPACE     3
0027     /* FDT_ERR_NOSPACE: Operation needed to expand the device
0028      * tree, but its buffer did not have sufficient space to
0029      * contain the expanded tree. Use fdt_open_into() to move the
0030      * device tree to a buffer with more space. */
0031 
0032 /* Error codes: codes for bad parameters */
0033 #define FDT_ERR_BADOFFSET   4
0034     /* FDT_ERR_BADOFFSET: Function was passed a structure block
0035      * offset which is out-of-bounds, or which points to an
0036      * unsuitable part of the structure for the operation. */
0037 #define FDT_ERR_BADPATH     5
0038     /* FDT_ERR_BADPATH: Function was passed a badly formatted path
0039      * (e.g. missing a leading / for a function which requires an
0040      * absolute path) */
0041 #define FDT_ERR_BADPHANDLE  6
0042     /* FDT_ERR_BADPHANDLE: Function was passed an invalid phandle.
0043      * This can be caused either by an invalid phandle property
0044      * length, or the phandle value was either 0 or -1, which are
0045      * not permitted. */
0046 #define FDT_ERR_BADSTATE    7
0047     /* FDT_ERR_BADSTATE: Function was passed an incomplete device
0048      * tree created by the sequential-write functions, which is
0049      * not sufficiently complete for the requested operation. */
0050 
0051 /* Error codes: codes for bad device tree blobs */
0052 #define FDT_ERR_TRUNCATED   8
0053     /* FDT_ERR_TRUNCATED: FDT or a sub-block is improperly
0054      * terminated (overflows, goes outside allowed bounds, or
0055      * isn't properly terminated).  */
0056 #define FDT_ERR_BADMAGIC    9
0057     /* FDT_ERR_BADMAGIC: Given "device tree" appears not to be a
0058      * device tree at all - it is missing the flattened device
0059      * tree magic number. */
0060 #define FDT_ERR_BADVERSION  10
0061     /* FDT_ERR_BADVERSION: Given device tree has a version which
0062      * can't be handled by the requested operation.  For
0063      * read-write functions, this may mean that fdt_open_into() is
0064      * required to convert the tree to the expected version. */
0065 #define FDT_ERR_BADSTRUCTURE    11
0066     /* FDT_ERR_BADSTRUCTURE: Given device tree has a corrupt
0067      * structure block or other serious error (e.g. misnested
0068      * nodes, or subnodes preceding properties). */
0069 #define FDT_ERR_BADLAYOUT   12
0070     /* FDT_ERR_BADLAYOUT: For read-write functions, the given
0071      * device tree has it's sub-blocks in an order that the
0072      * function can't handle (memory reserve map, then structure,
0073      * then strings).  Use fdt_open_into() to reorganize the tree
0074      * into a form suitable for the read-write operations. */
0075 
0076 /* "Can't happen" error indicating a bug in libfdt */
0077 #define FDT_ERR_INTERNAL    13
0078     /* FDT_ERR_INTERNAL: libfdt has failed an internal assertion.
0079      * Should never be returned, if it is, it indicates a bug in
0080      * libfdt itself. */
0081 
0082 /* Errors in device tree content */
0083 #define FDT_ERR_BADNCELLS   14
0084     /* FDT_ERR_BADNCELLS: Device tree has a #address-cells, #size-cells
0085      * or similar property with a bad format or value */
0086 
0087 #define FDT_ERR_BADVALUE    15
0088     /* FDT_ERR_BADVALUE: Device tree has a property with an unexpected
0089      * value. For example: a property expected to contain a string list
0090      * is not NUL-terminated within the length of its value. */
0091 
0092 #define FDT_ERR_BADOVERLAY  16
0093     /* FDT_ERR_BADOVERLAY: The device tree overlay, while
0094      * correctly structured, cannot be applied due to some
0095      * unexpected or missing value, property or node. */
0096 
0097 #define FDT_ERR_NOPHANDLES  17
0098     /* FDT_ERR_NOPHANDLES: The device tree doesn't have any
0099      * phandle available anymore without causing an overflow */
0100 
0101 #define FDT_ERR_BADFLAGS    18
0102     /* FDT_ERR_BADFLAGS: The function was passed a flags field that
0103      * contains invalid flags or an invalid combination of flags. */
0104 
0105 #define FDT_ERR_ALIGNMENT   19
0106     /* FDT_ERR_ALIGNMENT: The device tree base address is not 8-byte
0107      * aligned. */
0108 
0109 #define FDT_ERR_MAX     19
0110 
0111 /* constants */
0112 #define FDT_MAX_PHANDLE 0xfffffffe
0113     /* Valid values for phandles range from 1 to 2^32-2. */
0114 
0115 /**********************************************************************/
0116 /* Low-level functions (you probably don't need these)                */
0117 /**********************************************************************/
0118 
0119 #ifndef SWIG /* This function is not useful in Python */
0120 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int checklen);
0121 #endif
0122 static inline void *fdt_offset_ptr_w(void *fdt, int offset, int checklen)
0123 {
0124     return (void *)(uintptr_t)fdt_offset_ptr(fdt, offset, checklen);
0125 }
0126 
0127 uint32_t fdt_next_tag(const void *fdt, int offset, int *nextoffset);
0128 
0129 /*
0130  * External helpers to access words from a device tree blob. They're built
0131  * to work even with unaligned pointers on platforms (such as ARMv5) that don't
0132  * like unaligned loads and stores.
0133  */
0134 static inline uint16_t fdt16_ld(const fdt16_t *p)
0135 {
0136     const uint8_t *bp = (const uint8_t *)p;
0137 
0138     return ((uint16_t)bp[0] << 8) | bp[1];
0139 }
0140 
0141 static inline uint32_t fdt32_ld(const fdt32_t *p)
0142 {
0143     const uint8_t *bp = (const uint8_t *)p;
0144 
0145     return ((uint32_t)bp[0] << 24)
0146         | ((uint32_t)bp[1] << 16)
0147         | ((uint32_t)bp[2] << 8)
0148         | bp[3];
0149 }
0150 
0151 static inline void fdt32_st(void *property, uint32_t value)
0152 {
0153     uint8_t *bp = (uint8_t *)property;
0154 
0155     bp[0] = value >> 24;
0156     bp[1] = (value >> 16) & 0xff;
0157     bp[2] = (value >> 8) & 0xff;
0158     bp[3] = value & 0xff;
0159 }
0160 
0161 static inline uint64_t fdt64_ld(const fdt64_t *p)
0162 {
0163     const uint8_t *bp = (const uint8_t *)p;
0164 
0165     return ((uint64_t)bp[0] << 56)
0166         | ((uint64_t)bp[1] << 48)
0167         | ((uint64_t)bp[2] << 40)
0168         | ((uint64_t)bp[3] << 32)
0169         | ((uint64_t)bp[4] << 24)
0170         | ((uint64_t)bp[5] << 16)
0171         | ((uint64_t)bp[6] << 8)
0172         | bp[7];
0173 }
0174 
0175 static inline void fdt64_st(void *property, uint64_t value)
0176 {
0177     uint8_t *bp = (uint8_t *)property;
0178 
0179     bp[0] = value >> 56;
0180     bp[1] = (value >> 48) & 0xff;
0181     bp[2] = (value >> 40) & 0xff;
0182     bp[3] = (value >> 32) & 0xff;
0183     bp[4] = (value >> 24) & 0xff;
0184     bp[5] = (value >> 16) & 0xff;
0185     bp[6] = (value >> 8) & 0xff;
0186     bp[7] = value & 0xff;
0187 }
0188 
0189 /**********************************************************************/
0190 /* Traversal functions                                                */
0191 /**********************************************************************/
0192 
0193 int fdt_next_node(const void *fdt, int offset, int *depth);
0194 
0195 /**
0196  * fdt_first_subnode() - get offset of first direct subnode
0197  * @fdt:    FDT blob
0198  * @offset: Offset of node to check
0199  *
0200  * Return: offset of first subnode, or -FDT_ERR_NOTFOUND if there is none
0201  */
0202 int fdt_first_subnode(const void *fdt, int offset);
0203 
0204 /**
0205  * fdt_next_subnode() - get offset of next direct subnode
0206  * @fdt:    FDT blob
0207  * @offset: Offset of previous subnode
0208  *
0209  * After first calling fdt_first_subnode(), call this function repeatedly to
0210  * get direct subnodes of a parent node.
0211  *
0212  * Return: offset of next subnode, or -FDT_ERR_NOTFOUND if there are no more
0213  *         subnodes
0214  */
0215 int fdt_next_subnode(const void *fdt, int offset);
0216 
0217 /**
0218  * fdt_for_each_subnode - iterate over all subnodes of a parent
0219  *
0220  * @node:   child node (int, lvalue)
0221  * @fdt:    FDT blob (const void *)
0222  * @parent: parent node (int)
0223  *
0224  * This is actually a wrapper around a for loop and would be used like so:
0225  *
0226  *  fdt_for_each_subnode(node, fdt, parent) {
0227  *      Use node
0228  *      ...
0229  *  }
0230  *
0231  *  if ((node < 0) && (node != -FDT_ERR_NOTFOUND)) {
0232  *      Error handling
0233  *  }
0234  *
0235  * Note that this is implemented as a macro and @node is used as
0236  * iterator in the loop. The parent variable be constant or even a
0237  * literal.
0238  */
0239 #define fdt_for_each_subnode(node, fdt, parent)     \
0240     for (node = fdt_first_subnode(fdt, parent); \
0241          node >= 0;                 \
0242          node = fdt_next_subnode(fdt, node))
0243 
0244 /**********************************************************************/
0245 /* General functions                                                  */
0246 /**********************************************************************/
0247 #define fdt_get_header(fdt, field) \
0248     (fdt32_ld(&((const struct fdt_header *)(fdt))->field))
0249 #define fdt_magic(fdt)          (fdt_get_header(fdt, magic))
0250 #define fdt_totalsize(fdt)      (fdt_get_header(fdt, totalsize))
0251 #define fdt_off_dt_struct(fdt)      (fdt_get_header(fdt, off_dt_struct))
0252 #define fdt_off_dt_strings(fdt)     (fdt_get_header(fdt, off_dt_strings))
0253 #define fdt_off_mem_rsvmap(fdt)     (fdt_get_header(fdt, off_mem_rsvmap))
0254 #define fdt_version(fdt)        (fdt_get_header(fdt, version))
0255 #define fdt_last_comp_version(fdt)  (fdt_get_header(fdt, last_comp_version))
0256 #define fdt_boot_cpuid_phys(fdt)    (fdt_get_header(fdt, boot_cpuid_phys))
0257 #define fdt_size_dt_strings(fdt)    (fdt_get_header(fdt, size_dt_strings))
0258 #define fdt_size_dt_struct(fdt)     (fdt_get_header(fdt, size_dt_struct))
0259 
0260 #define fdt_set_hdr_(name) \
0261     static inline void fdt_set_##name(void *fdt, uint32_t val) \
0262     { \
0263         struct fdt_header *fdth = (struct fdt_header *)fdt; \
0264         fdth->name = cpu_to_fdt32(val); \
0265     }
0266 fdt_set_hdr_(magic);
0267 fdt_set_hdr_(totalsize);
0268 fdt_set_hdr_(off_dt_struct);
0269 fdt_set_hdr_(off_dt_strings);
0270 fdt_set_hdr_(off_mem_rsvmap);
0271 fdt_set_hdr_(version);
0272 fdt_set_hdr_(last_comp_version);
0273 fdt_set_hdr_(boot_cpuid_phys);
0274 fdt_set_hdr_(size_dt_strings);
0275 fdt_set_hdr_(size_dt_struct);
0276 #undef fdt_set_hdr_
0277 
0278 /**
0279  * fdt_header_size - return the size of the tree's header
0280  * @fdt: pointer to a flattened device tree
0281  *
0282  * Return: size of DTB header in bytes
0283  */
0284 size_t fdt_header_size(const void *fdt);
0285 
0286 /**
0287  * fdt_header_size_ - internal function to get header size from a version number
0288  * @version: devicetree version number
0289  *
0290  * Return: size of DTB header in bytes
0291  */
0292 size_t fdt_header_size_(uint32_t version);
0293 
0294 /**
0295  * fdt_check_header - sanity check a device tree header
0296  * @fdt: pointer to data which might be a flattened device tree
0297  *
0298  * fdt_check_header() checks that the given buffer contains what
0299  * appears to be a flattened device tree, and that the header contains
0300  * valid information (to the extent that can be determined from the
0301  * header alone).
0302  *
0303  * returns:
0304  *     0, if the buffer appears to contain a valid device tree
0305  *     -FDT_ERR_BADMAGIC,
0306  *     -FDT_ERR_BADVERSION,
0307  *     -FDT_ERR_BADSTATE,
0308  *     -FDT_ERR_TRUNCATED, standard meanings, as above
0309  */
0310 int fdt_check_header(const void *fdt);
0311 
0312 /**
0313  * fdt_move - move a device tree around in memory
0314  * @fdt: pointer to the device tree to move
0315  * @buf: pointer to memory where the device is to be moved
0316  * @bufsize: size of the memory space at buf
0317  *
0318  * fdt_move() relocates, if possible, the device tree blob located at
0319  * fdt to the buffer at buf of size bufsize.  The buffer may overlap
0320  * with the existing device tree blob at fdt.  Therefore,
0321  *     fdt_move(fdt, fdt, fdt_totalsize(fdt))
0322  * should always succeed.
0323  *
0324  * returns:
0325  *     0, on success
0326  *     -FDT_ERR_NOSPACE, bufsize is insufficient to contain the device tree
0327  *     -FDT_ERR_BADMAGIC,
0328  *     -FDT_ERR_BADVERSION,
0329  *     -FDT_ERR_BADSTATE, standard meanings
0330  */
0331 int fdt_move(const void *fdt, void *buf, int bufsize);
0332 
0333 /**********************************************************************/
0334 /* Read-only functions                                                */
0335 /**********************************************************************/
0336 
0337 int fdt_check_full(const void *fdt, size_t bufsize);
0338 
0339 /**
0340  * fdt_get_string - retrieve a string from the strings block of a device tree
0341  * @fdt: pointer to the device tree blob
0342  * @stroffset: offset of the string within the strings block (native endian)
0343  * @lenp: optional pointer to return the string's length
0344  *
0345  * fdt_get_string() retrieves a pointer to a single string from the
0346  * strings block of the device tree blob at fdt, and optionally also
0347  * returns the string's length in *lenp.
0348  *
0349  * returns:
0350  *     a pointer to the string, on success
0351  *     NULL, if stroffset is out of bounds, or doesn't point to a valid string
0352  */
0353 const char *fdt_get_string(const void *fdt, int stroffset, int *lenp);
0354 
0355 /**
0356  * fdt_string - retrieve a string from the strings block of a device tree
0357  * @fdt: pointer to the device tree blob
0358  * @stroffset: offset of the string within the strings block (native endian)
0359  *
0360  * fdt_string() retrieves a pointer to a single string from the
0361  * strings block of the device tree blob at fdt.
0362  *
0363  * returns:
0364  *     a pointer to the string, on success
0365  *     NULL, if stroffset is out of bounds, or doesn't point to a valid string
0366  */
0367 const char *fdt_string(const void *fdt, int stroffset);
0368 
0369 /**
0370  * fdt_find_max_phandle - find and return the highest phandle in a tree
0371  * @fdt: pointer to the device tree blob
0372  * @phandle: return location for the highest phandle value found in the tree
0373  *
0374  * fdt_find_max_phandle() finds the highest phandle value in the given device
0375  * tree. The value returned in @phandle is only valid if the function returns
0376  * success.
0377  *
0378  * returns:
0379  *     0 on success or a negative error code on failure
0380  */
0381 int fdt_find_max_phandle(const void *fdt, uint32_t *phandle);
0382 
0383 /**
0384  * fdt_get_max_phandle - retrieves the highest phandle in a tree
0385  * @fdt: pointer to the device tree blob
0386  *
0387  * fdt_get_max_phandle retrieves the highest phandle in the given
0388  * device tree. This will ignore badly formatted phandles, or phandles
0389  * with a value of 0 or -1.
0390  *
0391  * This function is deprecated in favour of fdt_find_max_phandle().
0392  *
0393  * returns:
0394  *      the highest phandle on success
0395  *      0, if no phandle was found in the device tree
0396  *      -1, if an error occurred
0397  */
0398 static inline uint32_t fdt_get_max_phandle(const void *fdt)
0399 {
0400     uint32_t phandle;
0401     int err;
0402 
0403     err = fdt_find_max_phandle(fdt, &phandle);
0404     if (err < 0)
0405         return (uint32_t)-1;
0406 
0407     return phandle;
0408 }
0409 
0410 /**
0411  * fdt_generate_phandle - return a new, unused phandle for a device tree blob
0412  * @fdt: pointer to the device tree blob
0413  * @phandle: return location for the new phandle
0414  *
0415  * Walks the device tree blob and looks for the highest phandle value. On
0416  * success, the new, unused phandle value (one higher than the previously
0417  * highest phandle value in the device tree blob) will be returned in the
0418  * @phandle parameter.
0419  *
0420  * Return: 0 on success or a negative error-code on failure
0421  */
0422 int fdt_generate_phandle(const void *fdt, uint32_t *phandle);
0423 
0424 /**
0425  * fdt_num_mem_rsv - retrieve the number of memory reserve map entries
0426  * @fdt: pointer to the device tree blob
0427  *
0428  * Returns the number of entries in the device tree blob's memory
0429  * reservation map.  This does not include the terminating 0,0 entry
0430  * or any other (0,0) entries reserved for expansion.
0431  *
0432  * returns:
0433  *     the number of entries
0434  */
0435 int fdt_num_mem_rsv(const void *fdt);
0436 
0437 /**
0438  * fdt_get_mem_rsv - retrieve one memory reserve map entry
0439  * @fdt: pointer to the device tree blob
0440  * @n: index of reserve map entry
0441  * @address: pointer to 64-bit variable to hold the start address
0442  * @size: pointer to 64-bit variable to hold the size of the entry
0443  *
0444  * On success, @address and @size will contain the address and size of
0445  * the n-th reserve map entry from the device tree blob, in
0446  * native-endian format.
0447  *
0448  * returns:
0449  *     0, on success
0450  *     -FDT_ERR_BADMAGIC,
0451  *     -FDT_ERR_BADVERSION,
0452  *     -FDT_ERR_BADSTATE, standard meanings
0453  */
0454 int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size);
0455 
0456 /**
0457  * fdt_subnode_offset_namelen - find a subnode based on substring
0458  * @fdt: pointer to the device tree blob
0459  * @parentoffset: structure block offset of a node
0460  * @name: name of the subnode to locate
0461  * @namelen: number of characters of name to consider
0462  *
0463  * Identical to fdt_subnode_offset(), but only examine the first
0464  * namelen characters of name for matching the subnode name.  This is
0465  * useful for finding subnodes based on a portion of a larger string,
0466  * such as a full path.
0467  *
0468  * Return: offset of the subnode or -FDT_ERR_NOTFOUND if name not found.
0469  */
0470 #ifndef SWIG /* Not available in Python */
0471 int fdt_subnode_offset_namelen(const void *fdt, int parentoffset,
0472                    const char *name, int namelen);
0473 #endif
0474 /**
0475  * fdt_subnode_offset - find a subnode of a given node
0476  * @fdt: pointer to the device tree blob
0477  * @parentoffset: structure block offset of a node
0478  * @name: name of the subnode to locate
0479  *
0480  * fdt_subnode_offset() finds a subnode of the node at structure block
0481  * offset parentoffset with the given name.  name may include a unit
0482  * address, in which case fdt_subnode_offset() will find the subnode
0483  * with that unit address, or the unit address may be omitted, in
0484  * which case fdt_subnode_offset() will find an arbitrary subnode
0485  * whose name excluding unit address matches the given name.
0486  *
0487  * returns:
0488  *  structure block offset of the requested subnode (>=0), on success
0489  *  -FDT_ERR_NOTFOUND, if the requested subnode does not exist
0490  *  -FDT_ERR_BADOFFSET, if parentoffset did not point to an FDT_BEGIN_NODE
0491  *      tag
0492  *  -FDT_ERR_BADMAGIC,
0493  *  -FDT_ERR_BADVERSION,
0494  *  -FDT_ERR_BADSTATE,
0495  *  -FDT_ERR_BADSTRUCTURE,
0496  *  -FDT_ERR_TRUNCATED, standard meanings.
0497  */
0498 int fdt_subnode_offset(const void *fdt, int parentoffset, const char *name);
0499 
0500 /**
0501  * fdt_path_offset_namelen - find a tree node by its full path
0502  * @fdt: pointer to the device tree blob
0503  * @path: full path of the node to locate
0504  * @namelen: number of characters of path to consider
0505  *
0506  * Identical to fdt_path_offset(), but only consider the first namelen
0507  * characters of path as the path name.
0508  *
0509  * Return: offset of the node or negative libfdt error value otherwise
0510  */
0511 #ifndef SWIG /* Not available in Python */
0512 int fdt_path_offset_namelen(const void *fdt, const char *path, int namelen);
0513 #endif
0514 
0515 /**
0516  * fdt_path_offset - find a tree node by its full path
0517  * @fdt: pointer to the device tree blob
0518  * @path: full path of the node to locate
0519  *
0520  * fdt_path_offset() finds a node of a given path in the device tree.
0521  * Each path component may omit the unit address portion, but the
0522  * results of this are undefined if any such path component is
0523  * ambiguous (that is if there are multiple nodes at the relevant
0524  * level matching the given component, differentiated only by unit
0525  * address).
0526  *
0527  * returns:
0528  *  structure block offset of the node with the requested path (>=0), on
0529  *      success
0530  *  -FDT_ERR_BADPATH, given path does not begin with '/' or is invalid
0531  *  -FDT_ERR_NOTFOUND, if the requested node does not exist
0532  *      -FDT_ERR_BADMAGIC,
0533  *  -FDT_ERR_BADVERSION,
0534  *  -FDT_ERR_BADSTATE,
0535  *  -FDT_ERR_BADSTRUCTURE,
0536  *  -FDT_ERR_TRUNCATED, standard meanings.
0537  */
0538 int fdt_path_offset(const void *fdt, const char *path);
0539 
0540 /**
0541  * fdt_get_name - retrieve the name of a given node
0542  * @fdt: pointer to the device tree blob
0543  * @nodeoffset: structure block offset of the starting node
0544  * @lenp: pointer to an integer variable (will be overwritten) or NULL
0545  *
0546  * fdt_get_name() retrieves the name (including unit address) of the
0547  * device tree node at structure block offset nodeoffset.  If lenp is
0548  * non-NULL, the length of this name is also returned, in the integer
0549  * pointed to by lenp.
0550  *
0551  * returns:
0552  *  pointer to the node's name, on success
0553  *      If lenp is non-NULL, *lenp contains the length of that name
0554  *          (>=0)
0555  *  NULL, on error
0556  *      if lenp is non-NULL *lenp contains an error code (<0):
0557  *      -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
0558  *          tag
0559  *      -FDT_ERR_BADMAGIC,
0560  *      -FDT_ERR_BADVERSION,
0561  *      -FDT_ERR_BADSTATE, standard meanings
0562  */
0563 const char *fdt_get_name(const void *fdt, int nodeoffset, int *lenp);
0564 
0565 /**
0566  * fdt_first_property_offset - find the offset of a node's first property
0567  * @fdt: pointer to the device tree blob
0568  * @nodeoffset: structure block offset of a node
0569  *
0570  * fdt_first_property_offset() finds the first property of the node at
0571  * the given structure block offset.
0572  *
0573  * returns:
0574  *  structure block offset of the property (>=0), on success
0575  *  -FDT_ERR_NOTFOUND, if the requested node has no properties
0576  *  -FDT_ERR_BADOFFSET, if nodeoffset did not point to an FDT_BEGIN_NODE tag
0577  *      -FDT_ERR_BADMAGIC,
0578  *  -FDT_ERR_BADVERSION,
0579  *  -FDT_ERR_BADSTATE,
0580  *  -FDT_ERR_BADSTRUCTURE,
0581  *  -FDT_ERR_TRUNCATED, standard meanings.
0582  */
0583 int fdt_first_property_offset(const void *fdt, int nodeoffset);
0584 
0585 /**
0586  * fdt_next_property_offset - step through a node's properties
0587  * @fdt: pointer to the device tree blob
0588  * @offset: structure block offset of a property
0589  *
0590  * fdt_next_property_offset() finds the property immediately after the
0591  * one at the given structure block offset.  This will be a property
0592  * of the same node as the given property.
0593  *
0594  * returns:
0595  *  structure block offset of the next property (>=0), on success
0596  *  -FDT_ERR_NOTFOUND, if the given property is the last in its node
0597  *  -FDT_ERR_BADOFFSET, if nodeoffset did not point to an FDT_PROP tag
0598  *      -FDT_ERR_BADMAGIC,
0599  *  -FDT_ERR_BADVERSION,
0600  *  -FDT_ERR_BADSTATE,
0601  *  -FDT_ERR_BADSTRUCTURE,
0602  *  -FDT_ERR_TRUNCATED, standard meanings.
0603  */
0604 int fdt_next_property_offset(const void *fdt, int offset);
0605 
0606 /**
0607  * fdt_for_each_property_offset - iterate over all properties of a node
0608  *
0609  * @property:   property offset (int, lvalue)
0610  * @fdt:    FDT blob (const void *)
0611  * @node:   node offset (int)
0612  *
0613  * This is actually a wrapper around a for loop and would be used like so:
0614  *
0615  *  fdt_for_each_property_offset(property, fdt, node) {
0616  *      Use property
0617  *      ...
0618  *  }
0619  *
0620  *  if ((property < 0) && (property != -FDT_ERR_NOTFOUND)) {
0621  *      Error handling
0622  *  }
0623  *
0624  * Note that this is implemented as a macro and property is used as
0625  * iterator in the loop. The node variable can be constant or even a
0626  * literal.
0627  */
0628 #define fdt_for_each_property_offset(property, fdt, node)   \
0629     for (property = fdt_first_property_offset(fdt, node);   \
0630          property >= 0;                 \
0631          property = fdt_next_property_offset(fdt, property))
0632 
0633 /**
0634  * fdt_get_property_by_offset - retrieve the property at a given offset
0635  * @fdt: pointer to the device tree blob
0636  * @offset: offset of the property to retrieve
0637  * @lenp: pointer to an integer variable (will be overwritten) or NULL
0638  *
0639  * fdt_get_property_by_offset() retrieves a pointer to the
0640  * fdt_property structure within the device tree blob at the given
0641  * offset.  If lenp is non-NULL, the length of the property value is
0642  * also returned, in the integer pointed to by lenp.
0643  *
0644  * Note that this code only works on device tree versions >= 16. fdt_getprop()
0645  * works on all versions.
0646  *
0647  * returns:
0648  *  pointer to the structure representing the property
0649  *      if lenp is non-NULL, *lenp contains the length of the property
0650  *      value (>=0)
0651  *  NULL, on error
0652  *      if lenp is non-NULL, *lenp contains an error code (<0):
0653  *      -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_PROP tag
0654  *      -FDT_ERR_BADMAGIC,
0655  *      -FDT_ERR_BADVERSION,
0656  *      -FDT_ERR_BADSTATE,
0657  *      -FDT_ERR_BADSTRUCTURE,
0658  *      -FDT_ERR_TRUNCATED, standard meanings
0659  */
0660 const struct fdt_property *fdt_get_property_by_offset(const void *fdt,
0661                               int offset,
0662                               int *lenp);
0663 static inline struct fdt_property *fdt_get_property_by_offset_w(void *fdt,
0664                                 int offset,
0665                                 int *lenp)
0666 {
0667     return (struct fdt_property *)(uintptr_t)
0668         fdt_get_property_by_offset(fdt, offset, lenp);
0669 }
0670 
0671 /**
0672  * fdt_get_property_namelen - find a property based on substring
0673  * @fdt: pointer to the device tree blob
0674  * @nodeoffset: offset of the node whose property to find
0675  * @name: name of the property to find
0676  * @namelen: number of characters of name to consider
0677  * @lenp: pointer to an integer variable (will be overwritten) or NULL
0678  *
0679  * Identical to fdt_get_property(), but only examine the first namelen
0680  * characters of name for matching the property name.
0681  *
0682  * Return: pointer to the structure representing the property, or NULL
0683  *         if not found
0684  */
0685 #ifndef SWIG /* Not available in Python */
0686 const struct fdt_property *fdt_get_property_namelen(const void *fdt,
0687                             int nodeoffset,
0688                             const char *name,
0689                             int namelen, int *lenp);
0690 #endif
0691 
0692 /**
0693  * fdt_get_property - find a given property in a given node
0694  * @fdt: pointer to the device tree blob
0695  * @nodeoffset: offset of the node whose property to find
0696  * @name: name of the property to find
0697  * @lenp: pointer to an integer variable (will be overwritten) or NULL
0698  *
0699  * fdt_get_property() retrieves a pointer to the fdt_property
0700  * structure within the device tree blob corresponding to the property
0701  * named 'name' of the node at offset nodeoffset.  If lenp is
0702  * non-NULL, the length of the property value is also returned, in the
0703  * integer pointed to by lenp.
0704  *
0705  * returns:
0706  *  pointer to the structure representing the property
0707  *      if lenp is non-NULL, *lenp contains the length of the property
0708  *      value (>=0)
0709  *  NULL, on error
0710  *      if lenp is non-NULL, *lenp contains an error code (<0):
0711  *      -FDT_ERR_NOTFOUND, node does not have named property
0712  *      -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
0713  *          tag
0714  *      -FDT_ERR_BADMAGIC,
0715  *      -FDT_ERR_BADVERSION,
0716  *      -FDT_ERR_BADSTATE,
0717  *      -FDT_ERR_BADSTRUCTURE,
0718  *      -FDT_ERR_TRUNCATED, standard meanings
0719  */
0720 const struct fdt_property *fdt_get_property(const void *fdt, int nodeoffset,
0721                         const char *name, int *lenp);
0722 static inline struct fdt_property *fdt_get_property_w(void *fdt, int nodeoffset,
0723                               const char *name,
0724                               int *lenp)
0725 {
0726     return (struct fdt_property *)(uintptr_t)
0727         fdt_get_property(fdt, nodeoffset, name, lenp);
0728 }
0729 
0730 /**
0731  * fdt_getprop_by_offset - retrieve the value of a property at a given offset
0732  * @fdt: pointer to the device tree blob
0733  * @offset: offset of the property to read
0734  * @namep: pointer to a string variable (will be overwritten) or NULL
0735  * @lenp: pointer to an integer variable (will be overwritten) or NULL
0736  *
0737  * fdt_getprop_by_offset() retrieves a pointer to the value of the
0738  * property at structure block offset 'offset' (this will be a pointer
0739  * to within the device blob itself, not a copy of the value).  If
0740  * lenp is non-NULL, the length of the property value is also
0741  * returned, in the integer pointed to by lenp.  If namep is non-NULL,
0742  * the property's namne will also be returned in the char * pointed to
0743  * by namep (this will be a pointer to within the device tree's string
0744  * block, not a new copy of the name).
0745  *
0746  * returns:
0747  *  pointer to the property's value
0748  *      if lenp is non-NULL, *lenp contains the length of the property
0749  *      value (>=0)
0750  *      if namep is non-NULL *namep contiains a pointer to the property
0751  *      name.
0752  *  NULL, on error
0753  *      if lenp is non-NULL, *lenp contains an error code (<0):
0754  *      -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_PROP tag
0755  *      -FDT_ERR_BADMAGIC,
0756  *      -FDT_ERR_BADVERSION,
0757  *      -FDT_ERR_BADSTATE,
0758  *      -FDT_ERR_BADSTRUCTURE,
0759  *      -FDT_ERR_TRUNCATED, standard meanings
0760  */
0761 #ifndef SWIG /* This function is not useful in Python */
0762 const void *fdt_getprop_by_offset(const void *fdt, int offset,
0763                   const char **namep, int *lenp);
0764 #endif
0765 
0766 /**
0767  * fdt_getprop_namelen - get property value based on substring
0768  * @fdt: pointer to the device tree blob
0769  * @nodeoffset: offset of the node whose property to find
0770  * @name: name of the property to find
0771  * @namelen: number of characters of name to consider
0772  * @lenp: pointer to an integer variable (will be overwritten) or NULL
0773  *
0774  * Identical to fdt_getprop(), but only examine the first namelen
0775  * characters of name for matching the property name.
0776  *
0777  * Return: pointer to the property's value or NULL on error
0778  */
0779 #ifndef SWIG /* Not available in Python */
0780 const void *fdt_getprop_namelen(const void *fdt, int nodeoffset,
0781                 const char *name, int namelen, int *lenp);
0782 static inline void *fdt_getprop_namelen_w(void *fdt, int nodeoffset,
0783                       const char *name, int namelen,
0784                       int *lenp)
0785 {
0786     return (void *)(uintptr_t)fdt_getprop_namelen(fdt, nodeoffset, name,
0787                               namelen, lenp);
0788 }
0789 #endif
0790 
0791 /**
0792  * fdt_getprop - retrieve the value of a given property
0793  * @fdt: pointer to the device tree blob
0794  * @nodeoffset: offset of the node whose property to find
0795  * @name: name of the property to find
0796  * @lenp: pointer to an integer variable (will be overwritten) or NULL
0797  *
0798  * fdt_getprop() retrieves a pointer to the value of the property
0799  * named @name of the node at offset @nodeoffset (this will be a
0800  * pointer to within the device blob itself, not a copy of the value).
0801  * If @lenp is non-NULL, the length of the property value is also
0802  * returned, in the integer pointed to by @lenp.
0803  *
0804  * returns:
0805  *  pointer to the property's value
0806  *      if lenp is non-NULL, *lenp contains the length of the property
0807  *      value (>=0)
0808  *  NULL, on error
0809  *      if lenp is non-NULL, *lenp contains an error code (<0):
0810  *      -FDT_ERR_NOTFOUND, node does not have named property
0811  *      -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE
0812  *          tag
0813  *      -FDT_ERR_BADMAGIC,
0814  *      -FDT_ERR_BADVERSION,
0815  *      -FDT_ERR_BADSTATE,
0816  *      -FDT_ERR_BADSTRUCTURE,
0817  *      -FDT_ERR_TRUNCATED, standard meanings
0818  */
0819 const void *fdt_getprop(const void *fdt, int nodeoffset,
0820             const char *name, int *lenp);
0821 static inline void *fdt_getprop_w(void *fdt, int nodeoffset,
0822                   const char *name, int *lenp)
0823 {
0824     return (void *)(uintptr_t)fdt_getprop(fdt, nodeoffset, name, lenp);
0825 }
0826 
0827 /**
0828  * fdt_get_phandle - retrieve the phandle of a given node
0829  * @fdt: pointer to the device tree blob
0830  * @nodeoffset: structure block offset of the node
0831  *
0832  * fdt_get_phandle() retrieves the phandle of the device tree node at
0833  * structure block offset nodeoffset.
0834  *
0835  * returns:
0836  *  the phandle of the node at nodeoffset, on success (!= 0, != -1)
0837  *  0, if the node has no phandle, or another error occurs
0838  */
0839 uint32_t fdt_get_phandle(const void *fdt, int nodeoffset);
0840 
0841 /**
0842  * fdt_get_alias_namelen - get alias based on substring
0843  * @fdt: pointer to the device tree blob
0844  * @name: name of the alias th look up
0845  * @namelen: number of characters of name to consider
0846  *
0847  * Identical to fdt_get_alias(), but only examine the first @namelen
0848  * characters of @name for matching the alias name.
0849  *
0850  * Return: a pointer to the expansion of the alias named @name, if it exists,
0851  *     NULL otherwise
0852  */
0853 #ifndef SWIG /* Not available in Python */
0854 const char *fdt_get_alias_namelen(const void *fdt,
0855                   const char *name, int namelen);
0856 #endif
0857 
0858 /**
0859  * fdt_get_alias - retrieve the path referenced by a given alias
0860  * @fdt: pointer to the device tree blob
0861  * @name: name of the alias th look up
0862  *
0863  * fdt_get_alias() retrieves the value of a given alias.  That is, the
0864  * value of the property named @name in the node /aliases.
0865  *
0866  * returns:
0867  *  a pointer to the expansion of the alias named 'name', if it exists
0868  *  NULL, if the given alias or the /aliases node does not exist
0869  */
0870 const char *fdt_get_alias(const void *fdt, const char *name);
0871 
0872 /**
0873  * fdt_get_path - determine the full path of a node
0874  * @fdt: pointer to the device tree blob
0875  * @nodeoffset: offset of the node whose path to find
0876  * @buf: character buffer to contain the returned path (will be overwritten)
0877  * @buflen: size of the character buffer at buf
0878  *
0879  * fdt_get_path() computes the full path of the node at offset
0880  * nodeoffset, and records that path in the buffer at buf.
0881  *
0882  * NOTE: This function is expensive, as it must scan the device tree
0883  * structure from the start to nodeoffset.
0884  *
0885  * returns:
0886  *  0, on success
0887  *      buf contains the absolute path of the node at
0888  *      nodeoffset, as a NUL-terminated string.
0889  *  -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
0890  *  -FDT_ERR_NOSPACE, the path of the given node is longer than (bufsize-1)
0891  *      characters and will not fit in the given buffer.
0892  *  -FDT_ERR_BADMAGIC,
0893  *  -FDT_ERR_BADVERSION,
0894  *  -FDT_ERR_BADSTATE,
0895  *  -FDT_ERR_BADSTRUCTURE, standard meanings
0896  */
0897 int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen);
0898 
0899 /**
0900  * fdt_supernode_atdepth_offset - find a specific ancestor of a node
0901  * @fdt: pointer to the device tree blob
0902  * @nodeoffset: offset of the node whose parent to find
0903  * @supernodedepth: depth of the ancestor to find
0904  * @nodedepth: pointer to an integer variable (will be overwritten) or NULL
0905  *
0906  * fdt_supernode_atdepth_offset() finds an ancestor of the given node
0907  * at a specific depth from the root (where the root itself has depth
0908  * 0, its immediate subnodes depth 1 and so forth).  So
0909  *  fdt_supernode_atdepth_offset(fdt, nodeoffset, 0, NULL);
0910  * will always return 0, the offset of the root node.  If the node at
0911  * nodeoffset has depth D, then:
0912  *  fdt_supernode_atdepth_offset(fdt, nodeoffset, D, NULL);
0913  * will return nodeoffset itself.
0914  *
0915  * NOTE: This function is expensive, as it must scan the device tree
0916  * structure from the start to nodeoffset.
0917  *
0918  * returns:
0919  *  structure block offset of the node at node offset's ancestor
0920  *      of depth supernodedepth (>=0), on success
0921  *  -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
0922  *  -FDT_ERR_NOTFOUND, supernodedepth was greater than the depth of
0923  *      nodeoffset
0924  *  -FDT_ERR_BADMAGIC,
0925  *  -FDT_ERR_BADVERSION,
0926  *  -FDT_ERR_BADSTATE,
0927  *  -FDT_ERR_BADSTRUCTURE, standard meanings
0928  */
0929 int fdt_supernode_atdepth_offset(const void *fdt, int nodeoffset,
0930                  int supernodedepth, int *nodedepth);
0931 
0932 /**
0933  * fdt_node_depth - find the depth of a given node
0934  * @fdt: pointer to the device tree blob
0935  * @nodeoffset: offset of the node whose parent to find
0936  *
0937  * fdt_node_depth() finds the depth of a given node.  The root node
0938  * has depth 0, its immediate subnodes depth 1 and so forth.
0939  *
0940  * NOTE: This function is expensive, as it must scan the device tree
0941  * structure from the start to nodeoffset.
0942  *
0943  * returns:
0944  *  depth of the node at nodeoffset (>=0), on success
0945  *  -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
0946  *  -FDT_ERR_BADMAGIC,
0947  *  -FDT_ERR_BADVERSION,
0948  *  -FDT_ERR_BADSTATE,
0949  *  -FDT_ERR_BADSTRUCTURE, standard meanings
0950  */
0951 int fdt_node_depth(const void *fdt, int nodeoffset);
0952 
0953 /**
0954  * fdt_parent_offset - find the parent of a given node
0955  * @fdt: pointer to the device tree blob
0956  * @nodeoffset: offset of the node whose parent to find
0957  *
0958  * fdt_parent_offset() locates the parent node of a given node (that
0959  * is, it finds the offset of the node which contains the node at
0960  * nodeoffset as a subnode).
0961  *
0962  * NOTE: This function is expensive, as it must scan the device tree
0963  * structure from the start to nodeoffset, *twice*.
0964  *
0965  * returns:
0966  *  structure block offset of the parent of the node at nodeoffset
0967  *      (>=0), on success
0968  *  -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
0969  *  -FDT_ERR_BADMAGIC,
0970  *  -FDT_ERR_BADVERSION,
0971  *  -FDT_ERR_BADSTATE,
0972  *  -FDT_ERR_BADSTRUCTURE, standard meanings
0973  */
0974 int fdt_parent_offset(const void *fdt, int nodeoffset);
0975 
0976 /**
0977  * fdt_node_offset_by_prop_value - find nodes with a given property value
0978  * @fdt: pointer to the device tree blob
0979  * @startoffset: only find nodes after this offset
0980  * @propname: property name to check
0981  * @propval: property value to search for
0982  * @proplen: length of the value in propval
0983  *
0984  * fdt_node_offset_by_prop_value() returns the offset of the first
0985  * node after startoffset, which has a property named propname whose
0986  * value is of length proplen and has value equal to propval; or if
0987  * startoffset is -1, the very first such node in the tree.
0988  *
0989  * To iterate through all nodes matching the criterion, the following
0990  * idiom can be used:
0991  *  offset = fdt_node_offset_by_prop_value(fdt, -1, propname,
0992  *                         propval, proplen);
0993  *  while (offset != -FDT_ERR_NOTFOUND) {
0994  *      // other code here
0995  *      offset = fdt_node_offset_by_prop_value(fdt, offset, propname,
0996  *                             propval, proplen);
0997  *  }
0998  *
0999  * Note the -1 in the first call to the function, if 0 is used here
1000  * instead, the function will never locate the root node, even if it
1001  * matches the criterion.
1002  *
1003  * returns:
1004  *  structure block offset of the located node (>= 0, >startoffset),
1005  *       on success
1006  *  -FDT_ERR_NOTFOUND, no node matching the criterion exists in the
1007  *      tree after startoffset
1008  *  -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
1009  *  -FDT_ERR_BADMAGIC,
1010  *  -FDT_ERR_BADVERSION,
1011  *  -FDT_ERR_BADSTATE,
1012  *  -FDT_ERR_BADSTRUCTURE, standard meanings
1013  */
1014 int fdt_node_offset_by_prop_value(const void *fdt, int startoffset,
1015                   const char *propname,
1016                   const void *propval, int proplen);
1017 
1018 /**
1019  * fdt_node_offset_by_phandle - find the node with a given phandle
1020  * @fdt: pointer to the device tree blob
1021  * @phandle: phandle value
1022  *
1023  * fdt_node_offset_by_phandle() returns the offset of the node
1024  * which has the given phandle value.  If there is more than one node
1025  * in the tree with the given phandle (an invalid tree), results are
1026  * undefined.
1027  *
1028  * returns:
1029  *  structure block offset of the located node (>= 0), on success
1030  *  -FDT_ERR_NOTFOUND, no node with that phandle exists
1031  *  -FDT_ERR_BADPHANDLE, given phandle value was invalid (0 or -1)
1032  *  -FDT_ERR_BADMAGIC,
1033  *  -FDT_ERR_BADVERSION,
1034  *  -FDT_ERR_BADSTATE,
1035  *  -FDT_ERR_BADSTRUCTURE, standard meanings
1036  */
1037 int fdt_node_offset_by_phandle(const void *fdt, uint32_t phandle);
1038 
1039 /**
1040  * fdt_node_check_compatible - check a node's compatible property
1041  * @fdt: pointer to the device tree blob
1042  * @nodeoffset: offset of a tree node
1043  * @compatible: string to match against
1044  *
1045  * fdt_node_check_compatible() returns 0 if the given node contains a
1046  * @compatible property with the given string as one of its elements,
1047  * it returns non-zero otherwise, or on error.
1048  *
1049  * returns:
1050  *  0, if the node has a 'compatible' property listing the given string
1051  *  1, if the node has a 'compatible' property, but it does not list
1052  *      the given string
1053  *  -FDT_ERR_NOTFOUND, if the given node has no 'compatible' property
1054  *  -FDT_ERR_BADOFFSET, if nodeoffset does not refer to a BEGIN_NODE tag
1055  *  -FDT_ERR_BADMAGIC,
1056  *  -FDT_ERR_BADVERSION,
1057  *  -FDT_ERR_BADSTATE,
1058  *  -FDT_ERR_BADSTRUCTURE, standard meanings
1059  */
1060 int fdt_node_check_compatible(const void *fdt, int nodeoffset,
1061                   const char *compatible);
1062 
1063 /**
1064  * fdt_node_offset_by_compatible - find nodes with a given 'compatible' value
1065  * @fdt: pointer to the device tree blob
1066  * @startoffset: only find nodes after this offset
1067  * @compatible: 'compatible' string to match against
1068  *
1069  * fdt_node_offset_by_compatible() returns the offset of the first
1070  * node after startoffset, which has a 'compatible' property which
1071  * lists the given compatible string; or if startoffset is -1, the
1072  * very first such node in the tree.
1073  *
1074  * To iterate through all nodes matching the criterion, the following
1075  * idiom can be used:
1076  *  offset = fdt_node_offset_by_compatible(fdt, -1, compatible);
1077  *  while (offset != -FDT_ERR_NOTFOUND) {
1078  *      // other code here
1079  *      offset = fdt_node_offset_by_compatible(fdt, offset, compatible);
1080  *  }
1081  *
1082  * Note the -1 in the first call to the function, if 0 is used here
1083  * instead, the function will never locate the root node, even if it
1084  * matches the criterion.
1085  *
1086  * returns:
1087  *  structure block offset of the located node (>= 0, >startoffset),
1088  *       on success
1089  *  -FDT_ERR_NOTFOUND, no node matching the criterion exists in the
1090  *      tree after startoffset
1091  *  -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
1092  *  -FDT_ERR_BADMAGIC,
1093  *  -FDT_ERR_BADVERSION,
1094  *  -FDT_ERR_BADSTATE,
1095  *  -FDT_ERR_BADSTRUCTURE, standard meanings
1096  */
1097 int fdt_node_offset_by_compatible(const void *fdt, int startoffset,
1098                   const char *compatible);
1099 
1100 /**
1101  * fdt_stringlist_contains - check a string list property for a string
1102  * @strlist: Property containing a list of strings to check
1103  * @listlen: Length of property
1104  * @str: String to search for
1105  *
1106  * This is a utility function provided for convenience. The list contains
1107  * one or more strings, each terminated by \0, as is found in a device tree
1108  * "compatible" property.
1109  *
1110  * Return: 1 if the string is found in the list, 0 not found, or invalid list
1111  */
1112 int fdt_stringlist_contains(const char *strlist, int listlen, const char *str);
1113 
1114 /**
1115  * fdt_stringlist_count - count the number of strings in a string list
1116  * @fdt: pointer to the device tree blob
1117  * @nodeoffset: offset of a tree node
1118  * @property: name of the property containing the string list
1119  *
1120  * Return:
1121  *   the number of strings in the given property
1122  *   -FDT_ERR_BADVALUE if the property value is not NUL-terminated
1123  *   -FDT_ERR_NOTFOUND if the property does not exist
1124  */
1125 int fdt_stringlist_count(const void *fdt, int nodeoffset, const char *property);
1126 
1127 /**
1128  * fdt_stringlist_search - find a string in a string list and return its index
1129  * @fdt: pointer to the device tree blob
1130  * @nodeoffset: offset of a tree node
1131  * @property: name of the property containing the string list
1132  * @string: string to look up in the string list
1133  *
1134  * Note that it is possible for this function to succeed on property values
1135  * that are not NUL-terminated. That's because the function will stop after
1136  * finding the first occurrence of @string. This can for example happen with
1137  * small-valued cell properties, such as #address-cells, when searching for
1138  * the empty string.
1139  *
1140  * return:
1141  *   the index of the string in the list of strings
1142  *   -FDT_ERR_BADVALUE if the property value is not NUL-terminated
1143  *   -FDT_ERR_NOTFOUND if the property does not exist or does not contain
1144  *                     the given string
1145  */
1146 int fdt_stringlist_search(const void *fdt, int nodeoffset, const char *property,
1147               const char *string);
1148 
1149 /**
1150  * fdt_stringlist_get() - obtain the string at a given index in a string list
1151  * @fdt: pointer to the device tree blob
1152  * @nodeoffset: offset of a tree node
1153  * @property: name of the property containing the string list
1154  * @index: index of the string to return
1155  * @lenp: return location for the string length or an error code on failure
1156  *
1157  * Note that this will successfully extract strings from properties with
1158  * non-NUL-terminated values. For example on small-valued cell properties
1159  * this function will return the empty string.
1160  *
1161  * If non-NULL, the length of the string (on success) or a negative error-code
1162  * (on failure) will be stored in the integer pointer to by lenp.
1163  *
1164  * Return:
1165  *   A pointer to the string at the given index in the string list or NULL on
1166  *   failure. On success the length of the string will be stored in the memory
1167  *   location pointed to by the lenp parameter, if non-NULL. On failure one of
1168  *   the following negative error codes will be returned in the lenp parameter
1169  *   (if non-NULL):
1170  *     -FDT_ERR_BADVALUE if the property value is not NUL-terminated
1171  *     -FDT_ERR_NOTFOUND if the property does not exist
1172  */
1173 const char *fdt_stringlist_get(const void *fdt, int nodeoffset,
1174                    const char *property, int index,
1175                    int *lenp);
1176 
1177 /**********************************************************************/
1178 /* Read-only functions (addressing related)                           */
1179 /**********************************************************************/
1180 
1181 /**
1182  * FDT_MAX_NCELLS - maximum value for #address-cells and #size-cells
1183  *
1184  * This is the maximum value for #address-cells, #size-cells and
1185  * similar properties that will be processed by libfdt.  IEE1275
1186  * requires that OF implementations handle values up to 4.
1187  * Implementations may support larger values, but in practice higher
1188  * values aren't used.
1189  */
1190 #define FDT_MAX_NCELLS      4
1191 
1192 /**
1193  * fdt_address_cells - retrieve address size for a bus represented in the tree
1194  * @fdt: pointer to the device tree blob
1195  * @nodeoffset: offset of the node to find the address size for
1196  *
1197  * When the node has a valid #address-cells property, returns its value.
1198  *
1199  * returns:
1200  *  0 <= n < FDT_MAX_NCELLS, on success
1201  *      2, if the node has no #address-cells property
1202  *      -FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
1203  *      #address-cells property
1204  *  -FDT_ERR_BADMAGIC,
1205  *  -FDT_ERR_BADVERSION,
1206  *  -FDT_ERR_BADSTATE,
1207  *  -FDT_ERR_BADSTRUCTURE,
1208  *  -FDT_ERR_TRUNCATED, standard meanings
1209  */
1210 int fdt_address_cells(const void *fdt, int nodeoffset);
1211 
1212 /**
1213  * fdt_size_cells - retrieve address range size for a bus represented in the
1214  *                  tree
1215  * @fdt: pointer to the device tree blob
1216  * @nodeoffset: offset of the node to find the address range size for
1217  *
1218  * When the node has a valid #size-cells property, returns its value.
1219  *
1220  * returns:
1221  *  0 <= n < FDT_MAX_NCELLS, on success
1222  *      1, if the node has no #size-cells property
1223  *      -FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
1224  *      #size-cells property
1225  *  -FDT_ERR_BADMAGIC,
1226  *  -FDT_ERR_BADVERSION,
1227  *  -FDT_ERR_BADSTATE,
1228  *  -FDT_ERR_BADSTRUCTURE,
1229  *  -FDT_ERR_TRUNCATED, standard meanings
1230  */
1231 int fdt_size_cells(const void *fdt, int nodeoffset);
1232 
1233 
1234 /**********************************************************************/
1235 /* Write-in-place functions                                           */
1236 /**********************************************************************/
1237 
1238 /**
1239  * fdt_setprop_inplace_namelen_partial - change a property's value,
1240  *                                       but not its size
1241  * @fdt: pointer to the device tree blob
1242  * @nodeoffset: offset of the node whose property to change
1243  * @name: name of the property to change
1244  * @namelen: number of characters of name to consider
1245  * @idx: index of the property to change in the array
1246  * @val: pointer to data to replace the property value with
1247  * @len: length of the property value
1248  *
1249  * Identical to fdt_setprop_inplace(), but modifies the given property
1250  * starting from the given index, and using only the first characters
1251  * of the name. It is useful when you want to manipulate only one value of
1252  * an array and you have a string that doesn't end with \0.
1253  *
1254  * Return: 0 on success, negative libfdt error value otherwise
1255  */
1256 #ifndef SWIG /* Not available in Python */
1257 int fdt_setprop_inplace_namelen_partial(void *fdt, int nodeoffset,
1258                     const char *name, int namelen,
1259                     uint32_t idx, const void *val,
1260                     int len);
1261 #endif
1262 
1263 /**
1264  * fdt_setprop_inplace - change a property's value, but not its size
1265  * @fdt: pointer to the device tree blob
1266  * @nodeoffset: offset of the node whose property to change
1267  * @name: name of the property to change
1268  * @val: pointer to data to replace the property value with
1269  * @len: length of the property value
1270  *
1271  * fdt_setprop_inplace() replaces the value of a given property with
1272  * the data in val, of length len.  This function cannot change the
1273  * size of a property, and so will only work if len is equal to the
1274  * current length of the property.
1275  *
1276  * This function will alter only the bytes in the blob which contain
1277  * the given property value, and will not alter or move any other part
1278  * of the tree.
1279  *
1280  * returns:
1281  *  0, on success
1282  *  -FDT_ERR_NOSPACE, if len is not equal to the property's current length
1283  *  -FDT_ERR_NOTFOUND, node does not have the named property
1284  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1285  *  -FDT_ERR_BADMAGIC,
1286  *  -FDT_ERR_BADVERSION,
1287  *  -FDT_ERR_BADSTATE,
1288  *  -FDT_ERR_BADSTRUCTURE,
1289  *  -FDT_ERR_TRUNCATED, standard meanings
1290  */
1291 #ifndef SWIG /* Not available in Python */
1292 int fdt_setprop_inplace(void *fdt, int nodeoffset, const char *name,
1293             const void *val, int len);
1294 #endif
1295 
1296 /**
1297  * fdt_setprop_inplace_u32 - change the value of a 32-bit integer property
1298  * @fdt: pointer to the device tree blob
1299  * @nodeoffset: offset of the node whose property to change
1300  * @name: name of the property to change
1301  * @val: 32-bit integer value to replace the property with
1302  *
1303  * fdt_setprop_inplace_u32() replaces the value of a given property
1304  * with the 32-bit integer value in val, converting val to big-endian
1305  * if necessary.  This function cannot change the size of a property,
1306  * and so will only work if the property already exists and has length
1307  * 4.
1308  *
1309  * This function will alter only the bytes in the blob which contain
1310  * the given property value, and will not alter or move any other part
1311  * of the tree.
1312  *
1313  * returns:
1314  *  0, on success
1315  *  -FDT_ERR_NOSPACE, if the property's length is not equal to 4
1316  *  -FDT_ERR_NOTFOUND, node does not have the named property
1317  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1318  *  -FDT_ERR_BADMAGIC,
1319  *  -FDT_ERR_BADVERSION,
1320  *  -FDT_ERR_BADSTATE,
1321  *  -FDT_ERR_BADSTRUCTURE,
1322  *  -FDT_ERR_TRUNCATED, standard meanings
1323  */
1324 static inline int fdt_setprop_inplace_u32(void *fdt, int nodeoffset,
1325                       const char *name, uint32_t val)
1326 {
1327     fdt32_t tmp = cpu_to_fdt32(val);
1328     return fdt_setprop_inplace(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1329 }
1330 
1331 /**
1332  * fdt_setprop_inplace_u64 - change the value of a 64-bit integer property
1333  * @fdt: pointer to the device tree blob
1334  * @nodeoffset: offset of the node whose property to change
1335  * @name: name of the property to change
1336  * @val: 64-bit integer value to replace the property with
1337  *
1338  * fdt_setprop_inplace_u64() replaces the value of a given property
1339  * with the 64-bit integer value in val, converting val to big-endian
1340  * if necessary.  This function cannot change the size of a property,
1341  * and so will only work if the property already exists and has length
1342  * 8.
1343  *
1344  * This function will alter only the bytes in the blob which contain
1345  * the given property value, and will not alter or move any other part
1346  * of the tree.
1347  *
1348  * returns:
1349  *  0, on success
1350  *  -FDT_ERR_NOSPACE, if the property's length is not equal to 8
1351  *  -FDT_ERR_NOTFOUND, node does not have the named property
1352  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1353  *  -FDT_ERR_BADMAGIC,
1354  *  -FDT_ERR_BADVERSION,
1355  *  -FDT_ERR_BADSTATE,
1356  *  -FDT_ERR_BADSTRUCTURE,
1357  *  -FDT_ERR_TRUNCATED, standard meanings
1358  */
1359 static inline int fdt_setprop_inplace_u64(void *fdt, int nodeoffset,
1360                       const char *name, uint64_t val)
1361 {
1362     fdt64_t tmp = cpu_to_fdt64(val);
1363     return fdt_setprop_inplace(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1364 }
1365 
1366 /**
1367  * fdt_setprop_inplace_cell - change the value of a single-cell property
1368  * @fdt: pointer to the device tree blob
1369  * @nodeoffset: offset of the node containing the property
1370  * @name: name of the property to change the value of
1371  * @val: new value of the 32-bit cell
1372  *
1373  * This is an alternative name for fdt_setprop_inplace_u32()
1374  * Return: 0 on success, negative libfdt error number otherwise.
1375  */
1376 static inline int fdt_setprop_inplace_cell(void *fdt, int nodeoffset,
1377                        const char *name, uint32_t val)
1378 {
1379     return fdt_setprop_inplace_u32(fdt, nodeoffset, name, val);
1380 }
1381 
1382 /**
1383  * fdt_nop_property - replace a property with nop tags
1384  * @fdt: pointer to the device tree blob
1385  * @nodeoffset: offset of the node whose property to nop
1386  * @name: name of the property to nop
1387  *
1388  * fdt_nop_property() will replace a given property's representation
1389  * in the blob with FDT_NOP tags, effectively removing it from the
1390  * tree.
1391  *
1392  * This function will alter only the bytes in the blob which contain
1393  * the property, and will not alter or move any other part of the
1394  * tree.
1395  *
1396  * returns:
1397  *  0, on success
1398  *  -FDT_ERR_NOTFOUND, node does not have the named property
1399  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1400  *  -FDT_ERR_BADMAGIC,
1401  *  -FDT_ERR_BADVERSION,
1402  *  -FDT_ERR_BADSTATE,
1403  *  -FDT_ERR_BADSTRUCTURE,
1404  *  -FDT_ERR_TRUNCATED, standard meanings
1405  */
1406 int fdt_nop_property(void *fdt, int nodeoffset, const char *name);
1407 
1408 /**
1409  * fdt_nop_node - replace a node (subtree) with nop tags
1410  * @fdt: pointer to the device tree blob
1411  * @nodeoffset: offset of the node to nop
1412  *
1413  * fdt_nop_node() will replace a given node's representation in the
1414  * blob, including all its subnodes, if any, with FDT_NOP tags,
1415  * effectively removing it from the tree.
1416  *
1417  * This function will alter only the bytes in the blob which contain
1418  * the node and its properties and subnodes, and will not alter or
1419  * move any other part of the tree.
1420  *
1421  * returns:
1422  *  0, on success
1423  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1424  *  -FDT_ERR_BADMAGIC,
1425  *  -FDT_ERR_BADVERSION,
1426  *  -FDT_ERR_BADSTATE,
1427  *  -FDT_ERR_BADSTRUCTURE,
1428  *  -FDT_ERR_TRUNCATED, standard meanings
1429  */
1430 int fdt_nop_node(void *fdt, int nodeoffset);
1431 
1432 /**********************************************************************/
1433 /* Sequential write functions                                         */
1434 /**********************************************************************/
1435 
1436 /* fdt_create_with_flags flags */
1437 #define FDT_CREATE_FLAG_NO_NAME_DEDUP 0x1
1438     /* FDT_CREATE_FLAG_NO_NAME_DEDUP: Do not try to de-duplicate property
1439      * names in the fdt. This can result in faster creation times, but
1440      * a larger fdt. */
1441 
1442 #define FDT_CREATE_FLAGS_ALL    (FDT_CREATE_FLAG_NO_NAME_DEDUP)
1443 
1444 /**
1445  * fdt_create_with_flags - begin creation of a new fdt
1446  * @buf: pointer to memory allocated where fdt will be created
1447  * @bufsize: size of the memory space at fdt
1448  * @flags: a valid combination of FDT_CREATE_FLAG_ flags, or 0.
1449  *
1450  * fdt_create_with_flags() begins the process of creating a new fdt with
1451  * the sequential write interface.
1452  *
1453  * fdt creation process must end with fdt_finished() to produce a valid fdt.
1454  *
1455  * returns:
1456  *  0, on success
1457  *  -FDT_ERR_NOSPACE, bufsize is insufficient for a minimal fdt
1458  *  -FDT_ERR_BADFLAGS, flags is not valid
1459  */
1460 int fdt_create_with_flags(void *buf, int bufsize, uint32_t flags);
1461 
1462 /**
1463  * fdt_create - begin creation of a new fdt
1464  * @buf: pointer to memory allocated where fdt will be created
1465  * @bufsize: size of the memory space at fdt
1466  *
1467  * fdt_create() is equivalent to fdt_create_with_flags() with flags=0.
1468  *
1469  * returns:
1470  *  0, on success
1471  *  -FDT_ERR_NOSPACE, bufsize is insufficient for a minimal fdt
1472  */
1473 int fdt_create(void *buf, int bufsize);
1474 
1475 int fdt_resize(void *fdt, void *buf, int bufsize);
1476 int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size);
1477 int fdt_finish_reservemap(void *fdt);
1478 int fdt_begin_node(void *fdt, const char *name);
1479 int fdt_property(void *fdt, const char *name, const void *val, int len);
1480 static inline int fdt_property_u32(void *fdt, const char *name, uint32_t val)
1481 {
1482     fdt32_t tmp = cpu_to_fdt32(val);
1483     return fdt_property(fdt, name, &tmp, sizeof(tmp));
1484 }
1485 static inline int fdt_property_u64(void *fdt, const char *name, uint64_t val)
1486 {
1487     fdt64_t tmp = cpu_to_fdt64(val);
1488     return fdt_property(fdt, name, &tmp, sizeof(tmp));
1489 }
1490 
1491 #ifndef SWIG /* Not available in Python */
1492 static inline int fdt_property_cell(void *fdt, const char *name, uint32_t val)
1493 {
1494     return fdt_property_u32(fdt, name, val);
1495 }
1496 #endif
1497 
1498 /**
1499  * fdt_property_placeholder - add a new property and return a ptr to its value
1500  *
1501  * @fdt: pointer to the device tree blob
1502  * @name: name of property to add
1503  * @len: length of property value in bytes
1504  * @valp: returns a pointer to where where the value should be placed
1505  *
1506  * returns:
1507  *  0, on success
1508  *  -FDT_ERR_BADMAGIC,
1509  *  -FDT_ERR_NOSPACE, standard meanings
1510  */
1511 int fdt_property_placeholder(void *fdt, const char *name, int len, void **valp);
1512 
1513 #define fdt_property_string(fdt, name, str) \
1514     fdt_property(fdt, name, str, strlen(str)+1)
1515 int fdt_end_node(void *fdt);
1516 int fdt_finish(void *fdt);
1517 
1518 /**********************************************************************/
1519 /* Read-write functions                                               */
1520 /**********************************************************************/
1521 
1522 int fdt_create_empty_tree(void *buf, int bufsize);
1523 int fdt_open_into(const void *fdt, void *buf, int bufsize);
1524 int fdt_pack(void *fdt);
1525 
1526 /**
1527  * fdt_add_mem_rsv - add one memory reserve map entry
1528  * @fdt: pointer to the device tree blob
1529  * @address: 64-bit start address of the reserve map entry
1530  * @size: 64-bit size of the reserved region
1531  *
1532  * Adds a reserve map entry to the given blob reserving a region at
1533  * address address of length size.
1534  *
1535  * This function will insert data into the reserve map and will
1536  * therefore change the indexes of some entries in the table.
1537  *
1538  * returns:
1539  *  0, on success
1540  *  -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1541  *      contain the new reservation entry
1542  *  -FDT_ERR_BADMAGIC,
1543  *  -FDT_ERR_BADVERSION,
1544  *  -FDT_ERR_BADSTATE,
1545  *  -FDT_ERR_BADSTRUCTURE,
1546  *  -FDT_ERR_BADLAYOUT,
1547  *  -FDT_ERR_TRUNCATED, standard meanings
1548  */
1549 int fdt_add_mem_rsv(void *fdt, uint64_t address, uint64_t size);
1550 
1551 /**
1552  * fdt_del_mem_rsv - remove a memory reserve map entry
1553  * @fdt: pointer to the device tree blob
1554  * @n: entry to remove
1555  *
1556  * fdt_del_mem_rsv() removes the n-th memory reserve map entry from
1557  * the blob.
1558  *
1559  * This function will delete data from the reservation table and will
1560  * therefore change the indexes of some entries in the table.
1561  *
1562  * returns:
1563  *  0, on success
1564  *  -FDT_ERR_NOTFOUND, there is no entry of the given index (i.e. there
1565  *      are less than n+1 reserve map entries)
1566  *  -FDT_ERR_BADMAGIC,
1567  *  -FDT_ERR_BADVERSION,
1568  *  -FDT_ERR_BADSTATE,
1569  *  -FDT_ERR_BADSTRUCTURE,
1570  *  -FDT_ERR_BADLAYOUT,
1571  *  -FDT_ERR_TRUNCATED, standard meanings
1572  */
1573 int fdt_del_mem_rsv(void *fdt, int n);
1574 
1575 /**
1576  * fdt_set_name - change the name of a given node
1577  * @fdt: pointer to the device tree blob
1578  * @nodeoffset: structure block offset of a node
1579  * @name: name to give the node
1580  *
1581  * fdt_set_name() replaces the name (including unit address, if any)
1582  * of the given node with the given string.  NOTE: this function can't
1583  * efficiently check if the new name is unique amongst the given
1584  * node's siblings; results are undefined if this function is invoked
1585  * with a name equal to one of the given node's siblings.
1586  *
1587  * This function may insert or delete data from the blob, and will
1588  * therefore change the offsets of some existing nodes.
1589  *
1590  * returns:
1591  *  0, on success
1592  *  -FDT_ERR_NOSPACE, there is insufficient free space in the blob
1593  *      to contain the new name
1594  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1595  *  -FDT_ERR_BADMAGIC,
1596  *  -FDT_ERR_BADVERSION,
1597  *  -FDT_ERR_BADSTATE, standard meanings
1598  */
1599 int fdt_set_name(void *fdt, int nodeoffset, const char *name);
1600 
1601 /**
1602  * fdt_setprop - create or change a property
1603  * @fdt: pointer to the device tree blob
1604  * @nodeoffset: offset of the node whose property to change
1605  * @name: name of the property to change
1606  * @val: pointer to data to set the property value to
1607  * @len: length of the property value
1608  *
1609  * fdt_setprop() sets the value of the named property in the given
1610  * node to the given value and length, creating the property if it
1611  * does not already exist.
1612  *
1613  * This function may insert or delete data from the blob, and will
1614  * therefore change the offsets of some existing nodes.
1615  *
1616  * returns:
1617  *  0, on success
1618  *  -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1619  *      contain the new property value
1620  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1621  *  -FDT_ERR_BADLAYOUT,
1622  *  -FDT_ERR_BADMAGIC,
1623  *  -FDT_ERR_BADVERSION,
1624  *  -FDT_ERR_BADSTATE,
1625  *  -FDT_ERR_BADSTRUCTURE,
1626  *  -FDT_ERR_BADLAYOUT,
1627  *  -FDT_ERR_TRUNCATED, standard meanings
1628  */
1629 int fdt_setprop(void *fdt, int nodeoffset, const char *name,
1630         const void *val, int len);
1631 
1632 /**
1633  * fdt_setprop_placeholder - allocate space for a property
1634  * @fdt: pointer to the device tree blob
1635  * @nodeoffset: offset of the node whose property to change
1636  * @name: name of the property to change
1637  * @len: length of the property value
1638  * @prop_data: return pointer to property data
1639  *
1640  * fdt_setprop_placeholer() allocates the named property in the given node.
1641  * If the property exists it is resized. In either case a pointer to the
1642  * property data is returned.
1643  *
1644  * This function may insert or delete data from the blob, and will
1645  * therefore change the offsets of some existing nodes.
1646  *
1647  * returns:
1648  *  0, on success
1649  *  -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1650  *      contain the new property value
1651  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1652  *  -FDT_ERR_BADLAYOUT,
1653  *  -FDT_ERR_BADMAGIC,
1654  *  -FDT_ERR_BADVERSION,
1655  *  -FDT_ERR_BADSTATE,
1656  *  -FDT_ERR_BADSTRUCTURE,
1657  *  -FDT_ERR_BADLAYOUT,
1658  *  -FDT_ERR_TRUNCATED, standard meanings
1659  */
1660 int fdt_setprop_placeholder(void *fdt, int nodeoffset, const char *name,
1661                 int len, void **prop_data);
1662 
1663 /**
1664  * fdt_setprop_u32 - set a property to a 32-bit integer
1665  * @fdt: pointer to the device tree blob
1666  * @nodeoffset: offset of the node whose property to change
1667  * @name: name of the property to change
1668  * @val: 32-bit integer value for the property (native endian)
1669  *
1670  * fdt_setprop_u32() sets the value of the named property in the given
1671  * node to the given 32-bit integer value (converting to big-endian if
1672  * necessary), or creates a new property with that value if it does
1673  * not already exist.
1674  *
1675  * This function may insert or delete data from the blob, and will
1676  * therefore change the offsets of some existing nodes.
1677  *
1678  * returns:
1679  *  0, on success
1680  *  -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1681  *      contain the new property value
1682  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1683  *  -FDT_ERR_BADLAYOUT,
1684  *  -FDT_ERR_BADMAGIC,
1685  *  -FDT_ERR_BADVERSION,
1686  *  -FDT_ERR_BADSTATE,
1687  *  -FDT_ERR_BADSTRUCTURE,
1688  *  -FDT_ERR_BADLAYOUT,
1689  *  -FDT_ERR_TRUNCATED, standard meanings
1690  */
1691 static inline int fdt_setprop_u32(void *fdt, int nodeoffset, const char *name,
1692                   uint32_t val)
1693 {
1694     fdt32_t tmp = cpu_to_fdt32(val);
1695     return fdt_setprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1696 }
1697 
1698 /**
1699  * fdt_setprop_u64 - set a property to a 64-bit integer
1700  * @fdt: pointer to the device tree blob
1701  * @nodeoffset: offset of the node whose property to change
1702  * @name: name of the property to change
1703  * @val: 64-bit integer value for the property (native endian)
1704  *
1705  * fdt_setprop_u64() sets the value of the named property in the given
1706  * node to the given 64-bit integer value (converting to big-endian if
1707  * necessary), or creates a new property with that value if it does
1708  * not already exist.
1709  *
1710  * This function may insert or delete data from the blob, and will
1711  * therefore change the offsets of some existing nodes.
1712  *
1713  * returns:
1714  *  0, on success
1715  *  -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1716  *      contain the new property value
1717  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1718  *  -FDT_ERR_BADLAYOUT,
1719  *  -FDT_ERR_BADMAGIC,
1720  *  -FDT_ERR_BADVERSION,
1721  *  -FDT_ERR_BADSTATE,
1722  *  -FDT_ERR_BADSTRUCTURE,
1723  *  -FDT_ERR_BADLAYOUT,
1724  *  -FDT_ERR_TRUNCATED, standard meanings
1725  */
1726 static inline int fdt_setprop_u64(void *fdt, int nodeoffset, const char *name,
1727                   uint64_t val)
1728 {
1729     fdt64_t tmp = cpu_to_fdt64(val);
1730     return fdt_setprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1731 }
1732 
1733 /**
1734  * fdt_setprop_cell - set a property to a single cell value
1735  * @fdt: pointer to the device tree blob
1736  * @nodeoffset: offset of the node whose property to change
1737  * @name: name of the property to change
1738  * @val: 32-bit integer value for the property (native endian)
1739  *
1740  * This is an alternative name for fdt_setprop_u32()
1741  *
1742  * Return: 0 on success, negative libfdt error value otherwise.
1743  */
1744 static inline int fdt_setprop_cell(void *fdt, int nodeoffset, const char *name,
1745                    uint32_t val)
1746 {
1747     return fdt_setprop_u32(fdt, nodeoffset, name, val);
1748 }
1749 
1750 /**
1751  * fdt_setprop_string - set a property to a string value
1752  * @fdt: pointer to the device tree blob
1753  * @nodeoffset: offset of the node whose property to change
1754  * @name: name of the property to change
1755  * @str: string value for the property
1756  *
1757  * fdt_setprop_string() sets the value of the named property in the
1758  * given node to the given string value (using the length of the
1759  * string to determine the new length of the property), or creates a
1760  * new property with that value if it does not already exist.
1761  *
1762  * This function may insert or delete data from the blob, and will
1763  * therefore change the offsets of some existing nodes.
1764  *
1765  * returns:
1766  *  0, on success
1767  *  -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1768  *      contain the new property value
1769  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1770  *  -FDT_ERR_BADLAYOUT,
1771  *  -FDT_ERR_BADMAGIC,
1772  *  -FDT_ERR_BADVERSION,
1773  *  -FDT_ERR_BADSTATE,
1774  *  -FDT_ERR_BADSTRUCTURE,
1775  *  -FDT_ERR_BADLAYOUT,
1776  *  -FDT_ERR_TRUNCATED, standard meanings
1777  */
1778 #define fdt_setprop_string(fdt, nodeoffset, name, str) \
1779     fdt_setprop((fdt), (nodeoffset), (name), (str), strlen(str)+1)
1780 
1781 
1782 /**
1783  * fdt_setprop_empty - set a property to an empty value
1784  * @fdt: pointer to the device tree blob
1785  * @nodeoffset: offset of the node whose property to change
1786  * @name: name of the property to change
1787  *
1788  * fdt_setprop_empty() sets the value of the named property in the
1789  * given node to an empty (zero length) value, or creates a new empty
1790  * property if it does not already exist.
1791  *
1792  * This function may insert or delete data from the blob, and will
1793  * therefore change the offsets of some existing nodes.
1794  *
1795  * returns:
1796  *  0, on success
1797  *  -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1798  *      contain the new property value
1799  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1800  *  -FDT_ERR_BADLAYOUT,
1801  *  -FDT_ERR_BADMAGIC,
1802  *  -FDT_ERR_BADVERSION,
1803  *  -FDT_ERR_BADSTATE,
1804  *  -FDT_ERR_BADSTRUCTURE,
1805  *  -FDT_ERR_BADLAYOUT,
1806  *  -FDT_ERR_TRUNCATED, standard meanings
1807  */
1808 #define fdt_setprop_empty(fdt, nodeoffset, name) \
1809     fdt_setprop((fdt), (nodeoffset), (name), NULL, 0)
1810 
1811 /**
1812  * fdt_appendprop - append to or create a property
1813  * @fdt: pointer to the device tree blob
1814  * @nodeoffset: offset of the node whose property to change
1815  * @name: name of the property to append to
1816  * @val: pointer to data to append to the property value
1817  * @len: length of the data to append to the property value
1818  *
1819  * fdt_appendprop() appends the value to the named property in the
1820  * given node, creating the property if it does not already exist.
1821  *
1822  * This function may insert data into the blob, and will therefore
1823  * change the offsets of some existing nodes.
1824  *
1825  * returns:
1826  *  0, on success
1827  *  -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1828  *      contain the new property value
1829  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1830  *  -FDT_ERR_BADLAYOUT,
1831  *  -FDT_ERR_BADMAGIC,
1832  *  -FDT_ERR_BADVERSION,
1833  *  -FDT_ERR_BADSTATE,
1834  *  -FDT_ERR_BADSTRUCTURE,
1835  *  -FDT_ERR_BADLAYOUT,
1836  *  -FDT_ERR_TRUNCATED, standard meanings
1837  */
1838 int fdt_appendprop(void *fdt, int nodeoffset, const char *name,
1839            const void *val, int len);
1840 
1841 /**
1842  * fdt_appendprop_u32 - append a 32-bit integer value to a property
1843  * @fdt: pointer to the device tree blob
1844  * @nodeoffset: offset of the node whose property to change
1845  * @name: name of the property to change
1846  * @val: 32-bit integer value to append to the property (native endian)
1847  *
1848  * fdt_appendprop_u32() appends the given 32-bit integer value
1849  * (converting to big-endian if necessary) to the value of the named
1850  * property in the given node, or creates a new property with that
1851  * value if it does not already exist.
1852  *
1853  * This function may insert data into the blob, and will therefore
1854  * change the offsets of some existing nodes.
1855  *
1856  * returns:
1857  *  0, on success
1858  *  -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1859  *      contain the new property value
1860  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1861  *  -FDT_ERR_BADLAYOUT,
1862  *  -FDT_ERR_BADMAGIC,
1863  *  -FDT_ERR_BADVERSION,
1864  *  -FDT_ERR_BADSTATE,
1865  *  -FDT_ERR_BADSTRUCTURE,
1866  *  -FDT_ERR_BADLAYOUT,
1867  *  -FDT_ERR_TRUNCATED, standard meanings
1868  */
1869 static inline int fdt_appendprop_u32(void *fdt, int nodeoffset,
1870                      const char *name, uint32_t val)
1871 {
1872     fdt32_t tmp = cpu_to_fdt32(val);
1873     return fdt_appendprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1874 }
1875 
1876 /**
1877  * fdt_appendprop_u64 - append a 64-bit integer value to a property
1878  * @fdt: pointer to the device tree blob
1879  * @nodeoffset: offset of the node whose property to change
1880  * @name: name of the property to change
1881  * @val: 64-bit integer value to append to the property (native endian)
1882  *
1883  * fdt_appendprop_u64() appends the given 64-bit integer value
1884  * (converting to big-endian if necessary) to the value of the named
1885  * property in the given node, or creates a new property with that
1886  * value if it does not already exist.
1887  *
1888  * This function may insert data into the blob, and will therefore
1889  * change the offsets of some existing nodes.
1890  *
1891  * returns:
1892  *  0, on success
1893  *  -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1894  *      contain the new property value
1895  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1896  *  -FDT_ERR_BADLAYOUT,
1897  *  -FDT_ERR_BADMAGIC,
1898  *  -FDT_ERR_BADVERSION,
1899  *  -FDT_ERR_BADSTATE,
1900  *  -FDT_ERR_BADSTRUCTURE,
1901  *  -FDT_ERR_BADLAYOUT,
1902  *  -FDT_ERR_TRUNCATED, standard meanings
1903  */
1904 static inline int fdt_appendprop_u64(void *fdt, int nodeoffset,
1905                      const char *name, uint64_t val)
1906 {
1907     fdt64_t tmp = cpu_to_fdt64(val);
1908     return fdt_appendprop(fdt, nodeoffset, name, &tmp, sizeof(tmp));
1909 }
1910 
1911 /**
1912  * fdt_appendprop_cell - append a single cell value to a property
1913  * @fdt: pointer to the device tree blob
1914  * @nodeoffset: offset of the node whose property to change
1915  * @name: name of the property to change
1916  * @val: 32-bit integer value to append to the property (native endian)
1917  *
1918  * This is an alternative name for fdt_appendprop_u32()
1919  *
1920  * Return: 0 on success, negative libfdt error value otherwise.
1921  */
1922 static inline int fdt_appendprop_cell(void *fdt, int nodeoffset,
1923                       const char *name, uint32_t val)
1924 {
1925     return fdt_appendprop_u32(fdt, nodeoffset, name, val);
1926 }
1927 
1928 /**
1929  * fdt_appendprop_string - append a string to a property
1930  * @fdt: pointer to the device tree blob
1931  * @nodeoffset: offset of the node whose property to change
1932  * @name: name of the property to change
1933  * @str: string value to append to the property
1934  *
1935  * fdt_appendprop_string() appends the given string to the value of
1936  * the named property in the given node, or creates a new property
1937  * with that value if it does not already exist.
1938  *
1939  * This function may insert data into the blob, and will therefore
1940  * change the offsets of some existing nodes.
1941  *
1942  * returns:
1943  *  0, on success
1944  *  -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1945  *      contain the new property value
1946  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1947  *  -FDT_ERR_BADLAYOUT,
1948  *  -FDT_ERR_BADMAGIC,
1949  *  -FDT_ERR_BADVERSION,
1950  *  -FDT_ERR_BADSTATE,
1951  *  -FDT_ERR_BADSTRUCTURE,
1952  *  -FDT_ERR_BADLAYOUT,
1953  *  -FDT_ERR_TRUNCATED, standard meanings
1954  */
1955 #define fdt_appendprop_string(fdt, nodeoffset, name, str) \
1956     fdt_appendprop((fdt), (nodeoffset), (name), (str), strlen(str)+1)
1957 
1958 /**
1959  * fdt_appendprop_addrrange - append a address range property
1960  * @fdt: pointer to the device tree blob
1961  * @parent: offset of the parent node
1962  * @nodeoffset: offset of the node to add a property at
1963  * @name: name of property
1964  * @addr: start address of a given range
1965  * @size: size of a given range
1966  *
1967  * fdt_appendprop_addrrange() appends an address range value (start
1968  * address and size) to the value of the named property in the given
1969  * node, or creates a new property with that value if it does not
1970  * already exist.
1971  * If "name" is not specified, a default "reg" is used.
1972  * Cell sizes are determined by parent's #address-cells and #size-cells.
1973  *
1974  * This function may insert data into the blob, and will therefore
1975  * change the offsets of some existing nodes.
1976  *
1977  * returns:
1978  *  0, on success
1979  *  -FDT_ERR_BADLAYOUT,
1980  *  -FDT_ERR_BADMAGIC,
1981  *  -FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
1982  *      #address-cells property
1983  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
1984  *  -FDT_ERR_BADSTATE,
1985  *  -FDT_ERR_BADSTRUCTURE,
1986  *  -FDT_ERR_BADVERSION,
1987  *  -FDT_ERR_BADVALUE, addr or size doesn't fit to respective cells size
1988  *  -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
1989  *      contain a new property
1990  *  -FDT_ERR_TRUNCATED, standard meanings
1991  */
1992 int fdt_appendprop_addrrange(void *fdt, int parent, int nodeoffset,
1993                  const char *name, uint64_t addr, uint64_t size);
1994 
1995 /**
1996  * fdt_delprop - delete a property
1997  * @fdt: pointer to the device tree blob
1998  * @nodeoffset: offset of the node whose property to nop
1999  * @name: name of the property to nop
2000  *
2001  * fdt_del_property() will delete the given property.
2002  *
2003  * This function will delete data from the blob, and will therefore
2004  * change the offsets of some existing nodes.
2005  *
2006  * returns:
2007  *  0, on success
2008  *  -FDT_ERR_NOTFOUND, node does not have the named property
2009  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
2010  *  -FDT_ERR_BADLAYOUT,
2011  *  -FDT_ERR_BADMAGIC,
2012  *  -FDT_ERR_BADVERSION,
2013  *  -FDT_ERR_BADSTATE,
2014  *  -FDT_ERR_BADSTRUCTURE,
2015  *  -FDT_ERR_TRUNCATED, standard meanings
2016  */
2017 int fdt_delprop(void *fdt, int nodeoffset, const char *name);
2018 
2019 /**
2020  * fdt_add_subnode_namelen - creates a new node based on substring
2021  * @fdt: pointer to the device tree blob
2022  * @parentoffset: structure block offset of a node
2023  * @name: name of the subnode to create
2024  * @namelen: number of characters of name to consider
2025  *
2026  * Identical to fdt_add_subnode(), but use only the first @namelen
2027  * characters of @name as the name of the new node.  This is useful for
2028  * creating subnodes based on a portion of a larger string, such as a
2029  * full path.
2030  *
2031  * Return: structure block offset of the created subnode (>=0),
2032  *     negative libfdt error value otherwise
2033  */
2034 #ifndef SWIG /* Not available in Python */
2035 int fdt_add_subnode_namelen(void *fdt, int parentoffset,
2036                 const char *name, int namelen);
2037 #endif
2038 
2039 /**
2040  * fdt_add_subnode - creates a new node
2041  * @fdt: pointer to the device tree blob
2042  * @parentoffset: structure block offset of a node
2043  * @name: name of the subnode to locate
2044  *
2045  * fdt_add_subnode() creates a new node as a subnode of the node at
2046  * structure block offset parentoffset, with the given name (which
2047  * should include the unit address, if any).
2048  *
2049  * This function will insert data into the blob, and will therefore
2050  * change the offsets of some existing nodes.
2051  *
2052  * returns:
2053  *  structure block offset of the created nodeequested subnode (>=0), on
2054  *      success
2055  *  -FDT_ERR_NOTFOUND, if the requested subnode does not exist
2056  *  -FDT_ERR_BADOFFSET, if parentoffset did not point to an FDT_BEGIN_NODE
2057  *      tag
2058  *  -FDT_ERR_EXISTS, if the node at parentoffset already has a subnode of
2059  *      the given name
2060  *  -FDT_ERR_NOSPACE, if there is insufficient free space in the
2061  *      blob to contain the new node
2062  *  -FDT_ERR_NOSPACE
2063  *  -FDT_ERR_BADLAYOUT
2064  *      -FDT_ERR_BADMAGIC,
2065  *  -FDT_ERR_BADVERSION,
2066  *  -FDT_ERR_BADSTATE,
2067  *  -FDT_ERR_BADSTRUCTURE,
2068  *  -FDT_ERR_TRUNCATED, standard meanings.
2069  */
2070 int fdt_add_subnode(void *fdt, int parentoffset, const char *name);
2071 
2072 /**
2073  * fdt_del_node - delete a node (subtree)
2074  * @fdt: pointer to the device tree blob
2075  * @nodeoffset: offset of the node to nop
2076  *
2077  * fdt_del_node() will remove the given node, including all its
2078  * subnodes if any, from the blob.
2079  *
2080  * This function will delete data from the blob, and will therefore
2081  * change the offsets of some existing nodes.
2082  *
2083  * returns:
2084  *  0, on success
2085  *  -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
2086  *  -FDT_ERR_BADLAYOUT,
2087  *  -FDT_ERR_BADMAGIC,
2088  *  -FDT_ERR_BADVERSION,
2089  *  -FDT_ERR_BADSTATE,
2090  *  -FDT_ERR_BADSTRUCTURE,
2091  *  -FDT_ERR_TRUNCATED, standard meanings
2092  */
2093 int fdt_del_node(void *fdt, int nodeoffset);
2094 
2095 /**
2096  * fdt_overlay_apply - Applies a DT overlay on a base DT
2097  * @fdt: pointer to the base device tree blob
2098  * @fdto: pointer to the device tree overlay blob
2099  *
2100  * fdt_overlay_apply() will apply the given device tree overlay on the
2101  * given base device tree.
2102  *
2103  * Expect the base device tree to be modified, even if the function
2104  * returns an error.
2105  *
2106  * returns:
2107  *  0, on success
2108  *  -FDT_ERR_NOSPACE, there's not enough space in the base device tree
2109  *  -FDT_ERR_NOTFOUND, the overlay points to some inexistant nodes or
2110  *      properties in the base DT
2111  *  -FDT_ERR_BADPHANDLE,
2112  *  -FDT_ERR_BADOVERLAY,
2113  *  -FDT_ERR_NOPHANDLES,
2114  *  -FDT_ERR_INTERNAL,
2115  *  -FDT_ERR_BADLAYOUT,
2116  *  -FDT_ERR_BADMAGIC,
2117  *  -FDT_ERR_BADOFFSET,
2118  *  -FDT_ERR_BADPATH,
2119  *  -FDT_ERR_BADVERSION,
2120  *  -FDT_ERR_BADSTRUCTURE,
2121  *  -FDT_ERR_BADSTATE,
2122  *  -FDT_ERR_TRUNCATED, standard meanings
2123  */
2124 int fdt_overlay_apply(void *fdt, void *fdto);
2125 
2126 /**
2127  * fdt_overlay_target_offset - retrieves the offset of a fragment's target
2128  * @fdt: Base device tree blob
2129  * @fdto: Device tree overlay blob
2130  * @fragment_offset: node offset of the fragment in the overlay
2131  * @pathp: pointer which receives the path of the target (or NULL)
2132  *
2133  * fdt_overlay_target_offset() retrieves the target offset in the base
2134  * device tree of a fragment, no matter how the actual targeting is
2135  * done (through a phandle or a path)
2136  *
2137  * returns:
2138  *      the targeted node offset in the base device tree
2139  *      Negative error code on error
2140  */
2141 int fdt_overlay_target_offset(const void *fdt, const void *fdto,
2142                   int fragment_offset, char const **pathp);
2143 
2144 /**********************************************************************/
2145 /* Debugging / informational functions                                */
2146 /**********************************************************************/
2147 
2148 const char *fdt_strerror(int errval);
2149 
2150 #ifdef __cplusplus
2151 }
2152 #endif
2153 
2154 #endif /* LIBFDT_H */