system76-edk2/EmbeddedPkg/Library/FdtLib/fdt.c

/*
 * libfdt - Flat Device Tree manipulation
 * Copyright (C) 2006 David Gibson, IBM Corporation.
 *
 * libfdt is dual licensed: you can use it either under the terms of
 * the GPL, or the BSD license, at your option.
 *
 *  a) This library is free software; you can redistribute it and/or
 *     modify it under the terms of the GNU General Public License as
 *     published by the Free Software Foundation; either version 2 of the
 *     License, or (at your option) any later version.
 *
 *     This library is distributed in the hope that it will be useful,
 *     but WITHOUT ANY WARRANTY; without even the implied warranty of
 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *     GNU General Public License for more details.
 *
 *     You should have received a copy of the GNU General Public
 *     License along with this library; if not, write to the Free
 *     Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
 *     MA 02110-1301 USA
 *
 * Alternatively,
 *
 *  b) Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *     1. Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *     2. Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include "libfdt_env.h"

#include <fdt.h>
#include <libfdt.h>

#include "libfdt_internal.h"

int
fdt_check_header (
  const void  *fdt
  )
{
  if (fdt_magic (fdt) == FDT_MAGIC) {
    /* Complete tree */
    if (fdt_version (fdt) < FDT_FIRST_SUPPORTED_VERSION) {
      return -FDT_ERR_BADVERSION;
    }

    if (fdt_last_comp_version (fdt) > FDT_LAST_SUPPORTED_VERSION) {
      return -FDT_ERR_BADVERSION;
    }
  } else if (fdt_magic (fdt) == FDT_SW_MAGIC) {
    /* Unfinished sequential-write blob */
    if (fdt_size_dt_struct (fdt) == 0) {
      return -FDT_ERR_BADSTATE;
    }
  } else {
    return -FDT_ERR_BADMAGIC;
  }

  return 0;
}

const void *
fdt_offset_ptr (
  const void    *fdt,
  int           offset,
  unsigned int  len
  )
{
  unsigned  absoffset = offset + fdt_off_dt_struct (fdt);

  if (  (absoffset < offset)
     || ((absoffset + len) < absoffset)
     || ((absoffset + len) > fdt_totalsize (fdt)))
  {
    return NULL;
  }

  if (fdt_version (fdt) >= 0x11) {
    if (  ((offset + len) < offset)
       || ((offset + len) > fdt_size_dt_struct (fdt)))
    {
      return NULL;
    }
  }

  return _fdt_offset_ptr (fdt, offset);
}

uint32_t
fdt_next_tag (
  const void  *fdt,
  int         startoffset,
  int         *nextoffset
  )
{
  const fdt32_t  *tagp, *lenp;
  uint32_t       tag;
  int            offset = startoffset;
  const char     *p;

  *nextoffset = -FDT_ERR_TRUNCATED;
  tagp        = fdt_offset_ptr (fdt, offset, FDT_TAGSIZE);
  if (!tagp) {
    return FDT_END;             /* premature end */
  }

  tag     = fdt32_to_cpu (*tagp);
  offset += FDT_TAGSIZE;

  *nextoffset = -FDT_ERR_BADSTRUCTURE;
  switch (tag) {
    case FDT_BEGIN_NODE:
      /* skip name */
      do {
        p = fdt_offset_ptr (fdt, offset++, 1);
      } while (p && (*p != '\0'));

      if (!p) {
        return FDT_END;                 /* premature end */
      }

      break;

    case FDT_PROP:
      lenp = fdt_offset_ptr (fdt, offset, sizeof (*lenp));
      if (!lenp) {
        return FDT_END;                 /* premature end */
      }

      /* skip-name offset, length and value */
      offset += sizeof (struct fdt_property) - FDT_TAGSIZE
                + fdt32_to_cpu (*lenp);
      break;

    case FDT_END:
    case FDT_END_NODE:
    case FDT_NOP:
      break;

    default:
      return FDT_END;
  }

  if (!fdt_offset_ptr (fdt, startoffset, offset - startoffset)) {
    return FDT_END;             /* premature end */
  }

  *nextoffset = FDT_TAGALIGN (offset);
  return tag;
}

int
_fdt_check_node_offset (
  const void  *fdt,
  int         offset
  )
{
  if (  (offset < 0) || (offset % FDT_TAGSIZE)
     || (fdt_next_tag (fdt, offset, &offset) != FDT_BEGIN_NODE))
  {
    return -FDT_ERR_BADOFFSET;
  }

  return offset;
}

int
_fdt_check_prop_offset (
  const void  *fdt,
  int         offset
  )
{
  if (  (offset < 0) || (offset % FDT_TAGSIZE)
     || (fdt_next_tag (fdt, offset, &offset) != FDT_PROP))
  {
    return -FDT_ERR_BADOFFSET;
  }

  return offset;
}

int
fdt_next_node (
  const void  *fdt,
  int         offset,
  int         *depth
  )
{
  int       nextoffset = 0;
  uint32_t  tag;

  if (offset >= 0) {
    if ((nextoffset = _fdt_check_node_offset (fdt, offset)) < 0) {
      return nextoffset;
    }
  }

  do {
    offset = nextoffset;
    tag    = fdt_next_tag (fdt, offset, &nextoffset);

    switch (tag) {
      case FDT_PROP:
      case FDT_NOP:
        break;

      case FDT_BEGIN_NODE:
        if (depth) {
          (*depth)++;
        }

        break;

      case FDT_END_NODE:
        if (depth && ((--(*depth)) < 0)) {
          return nextoffset;
        }

        break;

      case FDT_END:
        if (  (nextoffset >= 0)
           || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
        {
          return -FDT_ERR_NOTFOUND;
        } else {
          return nextoffset;
        }
    }
  } while (tag != FDT_BEGIN_NODE);

  return offset;
}

int
fdt_first_subnode (
  const void  *fdt,
  int         offset
  )
{
  int  depth = 0;

  offset = fdt_next_node (fdt, offset, &depth);
  if ((offset < 0) || (depth != 1)) {
    return -FDT_ERR_NOTFOUND;
  }

  return offset;
}

int
fdt_next_subnode (
  const void  *fdt,
  int         offset
  )
{
  int  depth = 1;

  /*
   * With respect to the parent, the depth of the next subnode will be
   * the same as the last.
   */
  do {
    offset = fdt_next_node (fdt, offset, &depth);
    if ((offset < 0) || (depth < 1)) {
      return -FDT_ERR_NOTFOUND;
    }
  } while (depth > 1);

  return offset;
}

const char *
_fdt_find_string (
  const char  *strtab,
  int         tabsize,
  const char  *s
  )
{
  int         len   = strlen (s) + 1;
  const char  *last = strtab + tabsize - len;
  const char  *p;

  for (p = strtab; p <= last; p++) {
    if (memcmp (p, s, len) == 0) {
      return p;
    }
  }

  return NULL;
}

int
fdt_move (
  const void  *fdt,
  void        *buf,
  int         bufsize
  )
{
  FDT_CHECK_HEADER (fdt);

  if (fdt_totalsize (fdt) > bufsize) {
    return -FDT_ERR_NOSPACE;
  }

  memmove (buf, fdt, fdt_totalsize (fdt));
  return 0;
}