libfdt/fdt.c

   1 /*
   2  * libfdt - Flat Device Tree manipulation
   3  * Copyright (C) 2006 David Gibson, IBM Corporation.
   4  *
   5  * libfdt is dual licensed: you can use it either under the terms of
   6  * the GPL, or the BSD license, at your option.
   7  *
   8  *  a) This library is free software; you can redistribute it and/or
   9  *     modify it under the terms of the GNU General Public License as
  10  *     published by the Free Software Foundation; either version 2 of the
  11  *     License, or (at your option) any later version.
  12  *
  13  *     This library is distributed in the hope that it will be useful,
  14  *     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *     GNU General Public License for more details.
  17  *
  18  *     You should have received a copy of the GNU General Public
  19  *     License along with this library; if not, write to the Free
  20  *     Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
  21  *     MA 02110-1301 USA
  22  *
  23  * Alternatively,
  24  *
  25  *  b) Redistribution and use in source and binary forms, with or
  26  *     without modification, are permitted provided that the following
  27  *     conditions are met:
  28  *
  29  *     1. Redistributions of source code must retain the above
  30  *        copyright notice, this list of conditions and the following
  31  *        disclaimer.
  32  *     2. Redistributions in binary form must reproduce the above
  33  *        copyright notice, this list of conditions and the following
  34  *        disclaimer in the documentation and/or other materials
  35  *        provided with the distribution.
  36  *
  37  *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
  38  *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
  39  *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  40  *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  41  *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  42  *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  43  *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  44  *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  45  *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  46  *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  47  *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  48  *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
  49  *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  50  */
  51 #include "libfdt_env.h"
  52
  53 #ifndef USE_HOSTCC
  54 #include <fdt.h>
  55 #include <libfdt.h>
  56 #else
  57 #include "fdt_host.h"
  58 #endif
  59
  60 #include "libfdt_internal.h"
  61
  62 int fdt_check_header(const void *fdt)
  63 {
  64         if (fdt_magic(fdt) == FDT_MAGIC) {
  65                 /* Complete tree */
  66                 if (fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
  67                         return -FDT_ERR_BADVERSION;
  68                 if (fdt_last_comp_version(fdt) > FDT_LAST_SUPPORTED_VERSION)
  69                         return -FDT_ERR_BADVERSION;
  70         } else if (fdt_magic(fdt) == SW_MAGIC) {
  71                 /* Unfinished sequential-write blob */
  72                 if (fdt_size_dt_struct(fdt) == 0)
  73                         return -FDT_ERR_BADSTATE;
  74         } else {
  75                 return -FDT_ERR_BADMAGIC;
  76         }
  77
  78         return 0;
  79 }
  80
  81 const void *fdt_offset_ptr(const void *fdt, int offset, int len)
  82 {
  83         const void *p;
  84
  85         if (fdt_version(fdt) >= 0x11)
  86                 if (((offset + len) < offset)
  87                     || ((offset + len) > fdt_size_dt_struct(fdt)))
  88                         return NULL;
  89
  90         p = _fdt_offset_ptr(fdt, offset);
  91
  92         if (p + len < p)
  93                 return NULL;
  94         return p;
  95 }
  96
  97 uint32_t fdt_next_tag(const void *fdt, int offset, int *nextoffset)
  98 {
  99         const uint32_t *tagp, *lenp;
 100         uint32_t tag;
 101         const char *p;
 102
 103         if (offset % FDT_TAGSIZE)
 104                 return -1;
 105
 106         tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
 107         if (! tagp)
 108                 return FDT_END; /* premature end */
 109         tag = fdt32_to_cpu(*tagp);
 110         offset += FDT_TAGSIZE;
 111
 112         switch (tag) {
 113         case FDT_BEGIN_NODE:
 114                 /* skip name */
 115                 do {
 116                         p = fdt_offset_ptr(fdt, offset++, 1);
 117                 } while (p && (*p != '\0'));
 118                 if (! p)
 119                         return FDT_END;
 120                 break;
 121         case FDT_PROP:
 122                 lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
 123                 if (! lenp)
 124                         return FDT_END;
 125                 /* skip name offset, length and value */
 126                 offset += 2*FDT_TAGSIZE + fdt32_to_cpu(*lenp);
 127                 break;
 128         }
 129
 130         if (nextoffset)
 131                 *nextoffset = ALIGN(offset, FDT_TAGSIZE);
 132
 133         return tag;
 134 }
 135
 136 int fdt_next_node(const void *fdt, int offset, int *depth)
 137 {
 138         int nextoffset = 0;
 139         uint32_t tag;
 140
 141         if (offset >= 0) {
 142                 tag = fdt_next_tag(fdt, offset, &nextoffset);
 143                 if (tag != FDT_BEGIN_NODE)
 144                         return -FDT_ERR_BADOFFSET;
 145         }
 146
 147         do {
 148                 offset = nextoffset;
 149                 tag = fdt_next_tag(fdt, offset, &nextoffset);
 150
 151                 switch (tag) {
 152                 case FDT_PROP:
 153                 case FDT_NOP:
 154                         break;
 155
 156                 case FDT_BEGIN_NODE:
 157                         if (depth)
 158                                 (*depth)++;
 159                         break;
 160
 161                 case FDT_END_NODE:
 162                         if (depth)
 163                                 (*depth)--;
 164                         break;
 165
 166                 case FDT_END:
 167                         return -FDT_ERR_NOTFOUND;
 168
 169                 default:
 170                         return -FDT_ERR_BADSTRUCTURE;
 171                 }
 172         } while (tag != FDT_BEGIN_NODE);
 173
 174         return offset;
 175 }
 176
 177 const char *_fdt_find_string(const char *strtab, int tabsize, const char *s)
 178 {
 179         int len = strlen(s) + 1;
 180         const char *last = strtab + tabsize - len;
 181         const char *p;
 182
 183         for (p = strtab; p <= last; p++)
 184                 if (memeq(p, s, len))
 185                         return p;
 186         return NULL;
 187 }
 188
 189 int fdt_move(const void *fdt, void *buf, int bufsize)
 190 {
 191         CHECK_HEADER(fdt);
 192
 193         if (fdt_totalsize(fdt) > bufsize)
 194                 return -FDT_ERR_NOSPACE;
 195
 196         memmove(buf, fdt, fdt_totalsize(fdt));
 197         return 0;
 198 }