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