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, 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 offset, int *nextoffset)
  94 {
  95         const uint32_t *tagp, *lenp;
  96         uint32_t tag;
  97         const char *p;
  98
  99         if (offset % FDT_TAGSIZE)
 100                 return -1;
 101
 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         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;
 116                 break;
 117         case FDT_PROP:
 118                 lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
 119                 if (! lenp)
 120                         return FDT_END;
 121                 /* skip name offset, length and value */
 122                 offset += 2*FDT_TAGSIZE + fdt32_to_cpu(*lenp);
 123                 break;
 124         }
 125
 126         if (nextoffset)
 127                 *nextoffset = FDT_TAGALIGN(offset);
 128
 129         return tag;
 130 }
 131
 132 int _fdt_check_node_offset(const void *fdt, int offset)
 133 {
 134         if ((offset < 0) || (offset % FDT_TAGSIZE)
 135             || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE))
 136                 return -FDT_ERR_BADOFFSET;
 137
 138         return offset;
 139 }
 140
 141 int fdt_next_node(const void *fdt, int offset, int *depth)
 142 {
 143         int nextoffset = 0;
 144         uint32_t tag;
 145
 146         if (offset >= 0)
 147                 if ((nextoffset = _fdt_check_node_offset(fdt, offset)) < 0)
 148                         return nextoffset;
 149
 150         do {
 151                 offset = nextoffset;
 152                 tag = fdt_next_tag(fdt, offset, &nextoffset);
 153
 154                 switch (tag) {
 155                 case FDT_PROP:
 156                 case FDT_NOP:
 157                         break;
 158
 159                 case FDT_BEGIN_NODE:
 160                         if (depth)
 161                                 (*depth)++;
 162                         break;
 163
 164                 case FDT_END_NODE:
 165                         if (depth)
 166                                 (*depth)--;
 167                         break;
 168
 169                 case FDT_END:
 170                         return -FDT_ERR_NOTFOUND;
 171
 172                 default:
 173                         return -FDT_ERR_BADSTRUCTURE;
 174                 }
 175         } while (tag != FDT_BEGIN_NODE);
 176
 177         return offset;
 178 }
 179
 180 const char *_fdt_find_string(const char *strtab, int tabsize, const char *s)
 181 {
 182         int len = strlen(s) + 1;
 183         const char *last = strtab + tabsize - len;
 184         const char *p;
 185
 186         for (p = strtab; p <= last; p++)
 187                 if (memcmp(p, s, len) == 0)
 188                         return p;
 189         return NULL;
 190 }
 191
 192 int fdt_move(const void *fdt, void *buf, int bufsize)
 193 {
 194         FDT_CHECK_HEADER(fdt);
 195
 196         if (fdt_totalsize(fdt) > bufsize)
 197                 return -FDT_ERR_NOSPACE;
 198
 199         memmove(buf, fdt, fdt_totalsize(fdt));
 200         return 0;
 201 }