linux/scripts/dtc/libfdt/fdt.c
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   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
  58int 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
  77const 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
  93uint32_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
 132int _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
 141int 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
 180const 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
 192int 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}
 202