EmbeddedPkg/Library/FdtLib/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 #include <fdt.h>
  54 #include <libfdt.h>
  55
  56 #include "libfdt_internal.h"
  57
  58 int
  59 fdt_check_header (
  60   const void  *fdt
  61   )
  62 {
  63   if (fdt_magic (fdt) == FDT_MAGIC) {
  64     /* Complete tree */
  65     if (fdt_version (fdt) < FDT_FIRST_SUPPORTED_VERSION) {
  66       return -FDT_ERR_BADVERSION;
  67     }
  68
  69     if (fdt_last_comp_version (fdt) > FDT_LAST_SUPPORTED_VERSION) {
  70       return -FDT_ERR_BADVERSION;
  71     }
  72   } else if (fdt_magic (fdt) == FDT_SW_MAGIC) {
  73     /* Unfinished sequential-write blob */
  74     if (fdt_size_dt_struct (fdt) == 0) {
  75       return -FDT_ERR_BADSTATE;
  76     }
  77   } else {
  78     return -FDT_ERR_BADMAGIC;
  79   }
  80
  81   return 0;
  82 }
  83
  84 const void *
  85 fdt_offset_ptr (
  86   const void    *fdt,
  87   int           offset,
  88   unsigned int  len
  89   )
  90 {
  91   unsigned  absoffset = offset + fdt_off_dt_struct (fdt);
  92
  93   if (  (absoffset < offset)
  94      || ((absoffset + len) < absoffset)
  95      || ((absoffset + len) > fdt_totalsize (fdt)))
  96   {
  97     return NULL;
  98   }
  99
 100   if (fdt_version (fdt) >= 0x11) {
 101     if (  ((offset + len) < offset)
 102        || ((offset + len) > fdt_size_dt_struct (fdt)))
 103     {
 104       return NULL;
 105     }
 106   }
 107
 108   return _fdt_offset_ptr (fdt, offset);
 109 }
 110
 111 uint32_t
 112 fdt_next_tag (
 113   const void  *fdt,
 114   int         startoffset,
 115   int         *nextoffset
 116   )
 117 {
 118   const fdt32_t  *tagp, *lenp;
 119   uint32_t       tag;
 120   int            offset = startoffset;
 121   const char     *p;
 122
 123   *nextoffset = -FDT_ERR_TRUNCATED;
 124   tagp        = fdt_offset_ptr (fdt, offset, FDT_TAGSIZE);
 125   if (!tagp) {
 126     return FDT_END;             /* premature end */
 127   }
 128
 129   tag     = fdt32_to_cpu (*tagp);
 130   offset += FDT_TAGSIZE;
 131
 132   *nextoffset = -FDT_ERR_BADSTRUCTURE;
 133   switch (tag) {
 134     case FDT_BEGIN_NODE:
 135       /* skip name */
 136       do {
 137         p = fdt_offset_ptr (fdt, offset++, 1);
 138       } while (p && (*p != '\0'));
 139
 140       if (!p) {
 141         return FDT_END;                 /* premature end */
 142       }
 143
 144       break;
 145
 146     case FDT_PROP:
 147       lenp = fdt_offset_ptr (fdt, offset, sizeof (*lenp));
 148       if (!lenp) {
 149         return FDT_END;                 /* premature end */
 150       }
 151
 152       /* skip-name offset, length and value */
 153       offset += sizeof (struct fdt_property) - FDT_TAGSIZE
 154                 + fdt32_to_cpu (*lenp);
 155       break;
 156
 157     case FDT_END:
 158     case FDT_END_NODE:
 159     case FDT_NOP:
 160       break;
 161
 162     default:
 163       return FDT_END;
 164   }
 165
 166   if (!fdt_offset_ptr (fdt, startoffset, offset - startoffset)) {
 167     return FDT_END;             /* premature end */
 168   }
 169
 170   *nextoffset = FDT_TAGALIGN (offset);
 171   return tag;
 172 }
 173
 174 int
 175 _fdt_check_node_offset (
 176   const void  *fdt,
 177   int         offset
 178   )
 179 {
 180   if (  (offset < 0) || (offset % FDT_TAGSIZE)
 181      || (fdt_next_tag (fdt, offset, &offset) != FDT_BEGIN_NODE))
 182   {
 183     return -FDT_ERR_BADOFFSET;
 184   }
 185
 186   return offset;
 187 }
 188
 189 int
 190 _fdt_check_prop_offset (
 191   const void  *fdt,
 192   int         offset
 193   )
 194 {
 195   if (  (offset < 0) || (offset % FDT_TAGSIZE)
 196      || (fdt_next_tag (fdt, offset, &offset) != FDT_PROP))
 197   {
 198     return -FDT_ERR_BADOFFSET;
 199   }
 200
 201   return offset;
 202 }
 203
 204 int
 205 fdt_next_node (
 206   const void  *fdt,
 207   int         offset,
 208   int         *depth
 209   )
 210 {
 211   int       nextoffset = 0;
 212   uint32_t  tag;
 213
 214   if (offset >= 0) {
 215     if ((nextoffset = _fdt_check_node_offset (fdt, offset)) < 0) {
 216       return nextoffset;
 217     }
 218   }
 219
 220   do {
 221     offset = nextoffset;
 222     tag    = fdt_next_tag (fdt, offset, &nextoffset);
 223
 224     switch (tag) {
 225       case FDT_PROP:
 226       case FDT_NOP:
 227         break;
 228
 229       case FDT_BEGIN_NODE:
 230         if (depth) {
 231           (*depth)++;
 232         }
 233
 234         break;
 235
 236       case FDT_END_NODE:
 237         if (depth && ((--(*depth)) < 0)) {
 238           return nextoffset;
 239         }
 240
 241         break;
 242
 243       case FDT_END:
 244         if (  (nextoffset >= 0)
 245            || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
 246         {
 247           return -FDT_ERR_NOTFOUND;
 248         } else {
 249           return nextoffset;
 250         }
 251     }
 252   } while (tag != FDT_BEGIN_NODE);
 253
 254   return offset;
 255 }
 256
 257 int
 258 fdt_first_subnode (
 259   const void  *fdt,
 260   int         offset
 261   )
 262 {
 263   int  depth = 0;
 264
 265   offset = fdt_next_node (fdt, offset, &depth);
 266   if ((offset < 0) || (depth != 1)) {
 267     return -FDT_ERR_NOTFOUND;
 268   }
 269
 270   return offset;
 271 }
 272
 273 int
 274 fdt_next_subnode (
 275   const void  *fdt,
 276   int         offset
 277   )
 278 {
 279   int  depth = 1;
 280
 281   /*
 282    * With respect to the parent, the depth of the next subnode will be
 283    * the same as the last.
 284    */
 285   do {
 286     offset = fdt_next_node (fdt, offset, &depth);
 287     if ((offset < 0) || (depth < 1)) {
 288       return -FDT_ERR_NOTFOUND;
 289     }
 290   } while (depth > 1);
 291
 292   return offset;
 293 }
 294
 295 const char *
 296 _fdt_find_string (
 297   const char  *strtab,
 298   int         tabsize,
 299   const char  *s
 300   )
 301 {
 302   int         len   = strlen (s) + 1;
 303   const char  *last = strtab + tabsize - len;
 304   const char  *p;
 305
 306   for (p = strtab; p <= last; p++) {
 307     if (memcmp (p, s, len) == 0) {
 308       return p;
 309     }
 310   }
 311
 312   return NULL;
 313 }
 314
 315 int
 316 fdt_move (
 317   const void  *fdt,
 318   void        *buf,
 319   int         bufsize
 320   )
 321 {
 322   FDT_CHECK_HEADER (fdt);
 323
 324   if (fdt_totalsize (fdt) > bufsize) {
 325     return -FDT_ERR_NOSPACE;
 326   }
 327
 328   memmove (buf, fdt, fdt_totalsize (fdt));
 329   return 0;
 330 }