scripts/dtc/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 #include <fdt.h>
  54 #include <libfdt.h>
  55
  56 #include "libfdt_internal.h"
  57
  58 int fdt_check_header(const void *fdt)
  59 {
  60         if (fdt_magic(fdt) == FDT_MAGIC) {
  61                 /* Complete tree */
  62                 if (fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
  63                         return -FDT_ERR_BADVERSION;
  64                 if (fdt_last_comp_version(fdt) > FDT_LAST_SUPPORTED_VERSION)
  65                         return -FDT_ERR_BADVERSION;
  66         } else if (fdt_magic(fdt) == FDT_SW_MAGIC) {
  67                 /* Unfinished sequential-write blob */
  68                 if (fdt_size_dt_struct(fdt) == 0)
  69                         return -FDT_ERR_BADSTATE;
  70         } else {
  71                 return -FDT_ERR_BADMAGIC;
  72         }
  73
  74         return 0;
  75 }
  76
  77 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
  78 {
  79         unsigned absoffset = offset + fdt_off_dt_struct(fdt);
  80
  81         if ((absoffset < offset)
  82             || ((absoffset + len) < absoffset)
  83             || (absoffset + len) > fdt_totalsize(fdt))
  84                 return NULL;
  85
  86         if (fdt_version(fdt) >= 0x11)
  87                 if (((offset + len) < offset)
  88                     || ((offset + len) > fdt_size_dt_struct(fdt)))
  89                         return NULL;
  90
  91         return fdt_offset_ptr_(fdt, offset);
  92 }
  93
  94 uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
  95 {
  96         const fdt32_t *tagp, *lenp;
  97         uint32_t tag;
  98         int offset = startoffset;
  99         const char *p;
 100
 101         *nextoffset = -FDT_ERR_TRUNCATED;
 102         tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
 103         if (!tagp)
 104                 return FDT_END; /* premature end */
 105         tag = fdt32_to_cpu(*tagp);
 106         offset += FDT_TAGSIZE;
 107
 108         *nextoffset = -FDT_ERR_BADSTRUCTURE;
 109         switch (tag) {
 110         case FDT_BEGIN_NODE:
 111                 /* skip name */
 112                 do {
 113                         p = fdt_offset_ptr(fdt, offset++, 1);
 114                 } while (p && (*p != '\0'));
 115                 if (!p)
 116                         return FDT_END; /* premature end */
 117                 break;
 118
 119         case FDT_PROP:
 120                 lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
 121                 if (!lenp)
 122                         return FDT_END; /* premature end */
 123                 /* skip-name offset, length and value */
 124                 offset += sizeof(struct fdt_property) - FDT_TAGSIZE
 125                         + fdt32_to_cpu(*lenp);
 126                 if (fdt_version(fdt) < 0x10 && fdt32_to_cpu(*lenp) >= 8 &&
 127                     ((offset - fdt32_to_cpu(*lenp)) % 8) != 0)
 128                         offset += 4;
 129                 break;
 130
 131         case FDT_END:
 132         case FDT_END_NODE:
 133         case FDT_NOP:
 134                 break;
 135
 136         default:
 137                 return FDT_END;
 138         }
 139
 140         if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
 141                 return FDT_END; /* premature end */
 142
 143         *nextoffset = FDT_TAGALIGN(offset);
 144         return tag;
 145 }
 146
 147 int fdt_check_node_offset_(const void *fdt, int offset)
 148 {
 149         if ((offset < 0) || (offset % FDT_TAGSIZE)
 150             || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE))
 151                 return -FDT_ERR_BADOFFSET;
 152
 153         return offset;
 154 }
 155
 156 int fdt_check_prop_offset_(const void *fdt, int offset)
 157 {
 158         if ((offset < 0) || (offset % FDT_TAGSIZE)
 159             || (fdt_next_tag(fdt, offset, &offset) != FDT_PROP))
 160                 return -FDT_ERR_BADOFFSET;
 161
 162         return offset;
 163 }
 164
 165 int fdt_next_node(const void *fdt, int offset, int *depth)
 166 {
 167         int nextoffset = 0;
 168         uint32_t tag;
 169
 170         if (offset >= 0)
 171                 if ((nextoffset = fdt_check_node_offset_(fdt, offset)) < 0)
 172                         return nextoffset;
 173
 174         do {
 175                 offset = nextoffset;
 176                 tag = fdt_next_tag(fdt, offset, &nextoffset);
 177
 178                 switch (tag) {
 179                 case FDT_PROP:
 180                 case FDT_NOP:
 181                         break;
 182
 183                 case FDT_BEGIN_NODE:
 184                         if (depth)
 185                                 (*depth)++;
 186                         break;
 187
 188                 case FDT_END_NODE:
 189                         if (depth && ((--(*depth)) < 0))
 190                                 return nextoffset;
 191                         break;
 192
 193                 case FDT_END:
 194                         if ((nextoffset >= 0)
 195                             || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
 196                                 return -FDT_ERR_NOTFOUND;
 197                         else
 198                                 return nextoffset;
 199                 }
 200         } while (tag != FDT_BEGIN_NODE);
 201
 202         return offset;
 203 }
 204
 205 int fdt_first_subnode(const void *fdt, int offset)
 206 {
 207         int depth = 0;
 208
 209         offset = fdt_next_node(fdt, offset, &depth);
 210         if (offset < 0 || depth != 1)
 211                 return -FDT_ERR_NOTFOUND;
 212
 213         return offset;
 214 }
 215
 216 int fdt_next_subnode(const void *fdt, int offset)
 217 {
 218         int depth = 1;
 219
 220         /*
 221          * With respect to the parent, the depth of the next subnode will be
 222          * the same as the last.
 223          */
 224         do {
 225                 offset = fdt_next_node(fdt, offset, &depth);
 226                 if (offset < 0 || depth < 1)
 227                         return -FDT_ERR_NOTFOUND;
 228         } while (depth > 1);
 229
 230         return offset;
 231 }
 232
 233 const char *fdt_find_string_(const char *strtab, int tabsize, const char *s)
 234 {
 235         int len = strlen(s) + 1;
 236         const char *last = strtab + tabsize - len;
 237         const char *p;
 238
 239         for (p = strtab; p <= last; p++)
 240                 if (memcmp(p, s, len) == 0)
 241                         return p;
 242         return NULL;
 243 }
 244
 245 int fdt_move(const void *fdt, void *buf, int bufsize)
 246 {
 247         FDT_CHECK_HEADER(fdt);
 248
 249         if (fdt_totalsize(fdt) > bufsize)
 250                 return -FDT_ERR_NOSPACE;
 251
 252         memmove(buf, fdt, fdt_totalsize(fdt));
 253         return 0;
 254 }