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 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                 break;
 127
 128         case FDT_END:
 129         case FDT_END_NODE:
 130         case FDT_NOP:
 131                 break;
 132
 133         default:
 134                 return FDT_END;
 135         }
 136
 137         if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
 138                 return FDT_END; /* premature end */
 139
 140         *nextoffset = FDT_TAGALIGN(offset);
 141         return tag;
 142 }
 143
 144 int _fdt_check_node_offset(const void *fdt, int offset)
 145 {
 146         if ((offset < 0) || (offset % FDT_TAGSIZE)
 147             || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE))
 148                 return -FDT_ERR_BADOFFSET;
 149
 150         return offset;
 151 }
 152
 153 int _fdt_check_prop_offset(const void *fdt, int offset)
 154 {
 155         if ((offset < 0) || (offset % FDT_TAGSIZE)
 156             || (fdt_next_tag(fdt, offset, &offset) != FDT_PROP))
 157                 return -FDT_ERR_BADOFFSET;
 158
 159         return offset;
 160 }
 161
 162 int fdt_next_node(const void *fdt, int offset, int *depth)
 163 {
 164         int nextoffset = 0;
 165         uint32_t tag;
 166
 167         if (offset >= 0)
 168                 if ((nextoffset = _fdt_check_node_offset(fdt, offset)) < 0)
 169                         return nextoffset;
 170
 171         do {
 172                 offset = nextoffset;
 173                 tag = fdt_next_tag(fdt, offset, &nextoffset);
 174
 175                 switch (tag) {
 176                 case FDT_PROP:
 177                 case FDT_NOP:
 178                         break;
 179
 180                 case FDT_BEGIN_NODE:
 181                         if (depth)
 182                                 (*depth)++;
 183                         break;
 184
 185                 case FDT_END_NODE:
 186                         if (depth && ((--(*depth)) < 0))
 187                                 return nextoffset;
 188                         break;
 189
 190                 case FDT_END:
 191                         if ((nextoffset >= 0)
 192                             || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
 193                                 return -FDT_ERR_NOTFOUND;
 194                         else
 195                                 return nextoffset;
 196                 }
 197         } while (tag != FDT_BEGIN_NODE);
 198
 199         return offset;
 200 }
 201
 202 int fdt_first_subnode(const void *fdt, int offset)
 203 {
 204         int depth = 0;
 205
 206         offset = fdt_next_node(fdt, offset, &depth);
 207         if (offset < 0 || depth != 1)
 208                 return -FDT_ERR_NOTFOUND;
 209
 210         return offset;
 211 }
 212
 213 int fdt_next_subnode(const void *fdt, int offset)
 214 {
 215         int depth = 1;
 216
 217         /*
 218          * With respect to the parent, the depth of the next subnode will be
 219          * the same as the last.
 220          */
 221         do {
 222                 offset = fdt_next_node(fdt, offset, &depth);
 223                 if (offset < 0 || depth < 1)
 224                         return -FDT_ERR_NOTFOUND;
 225         } while (depth > 1);
 226
 227         return offset;
 228 }
 229
 230 const char *_fdt_find_string(const char *strtab, int tabsize, const char *s)
 231 {
 232         int len = strlen(s) + 1;
 233         const char *last = strtab + tabsize - len;
 234         const char *p;
 235
 236         for (p = strtab; p <= last; p++)
 237                 if (memcmp(p, s, len) == 0)
 238                         return p;
 239         return NULL;
 240 }
 241
 242 int fdt_move(const void *fdt, void *buf, int bufsize)
 243 {
 244         FDT_CHECK_HEADER(fdt);
 245
 246         if (fdt_totalsize(fdt) > bufsize)
 247                 return -FDT_ERR_NOSPACE;
 248
 249         memmove(buf, fdt, fdt_totalsize(fdt));
 250         return 0;
 251 }