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fdt_ro.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"

#define CHECK_HEADER(fdt) \
      { \
            int err; \
            if ((err = fdt_check_header(fdt)) != 0) \
                  return err; \
      }

static int nodename_eq(const void *fdt, int offset,
                   const char *s, int len)
{
      const char *p = fdt_offset_ptr(fdt, offset, len+1);

      if (! p)
            /* short match */
            return 0;

      if (memcmp(p, s, len) != 0)
            return 0;

      if (p[len] == '\0')
            return 1;
      else if (!memchr(s, '@', len) && (p[len] == '@'))
            return 1;
      else
            return 0;
}

const char *fdt_string(const void *fdt, int stroffset)
{
      return (char *)fdt + fdt_off_dt_strings(fdt) + stroffset;
}

int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size)
{
      CHECK_HEADER(fdt);
      *address = fdt64_to_cpu(_fdt_mem_rsv(fdt, n)->address);
      *size = fdt64_to_cpu(_fdt_mem_rsv(fdt, n)->size);
      return 0;
}

int fdt_num_mem_rsv(const void *fdt)
{
      int i = 0;

      while (fdt64_to_cpu(_fdt_mem_rsv(fdt, i)->size) != 0)
            i++;
      return i;
}

int fdt_subnode_offset_namelen(const void *fdt, int parentoffset,
                         const char *name, int namelen)
{
      int level = 0;
      uint32_t tag;
      int offset, nextoffset;

      CHECK_HEADER(fdt);

      tag = fdt_next_tag(fdt, parentoffset, &nextoffset);
      if (tag != FDT_BEGIN_NODE)
            return -FDT_ERR_BADOFFSET;

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

            switch (tag) {
            case FDT_END:
                  return -FDT_ERR_TRUNCATED;

            case FDT_BEGIN_NODE:
                  level++;
                  if (level != 1)
                        continue;
                  if (nodename_eq(fdt, offset+FDT_TAGSIZE, name, namelen))
                        /* Found it! */
                        return offset;
                  break;

            case FDT_END_NODE:
                  level--;
                  break;

            case FDT_PROP:
            case FDT_NOP:
                  break;

            default:
                  return -FDT_ERR_BADSTRUCTURE;
            }
      } while (level >= 0);

      return -FDT_ERR_NOTFOUND;
}

int fdt_subnode_offset(const void *fdt, int parentoffset,
                   const char *name)
{
      return fdt_subnode_offset_namelen(fdt, parentoffset, name, strlen(name));
}

int fdt_path_offset(const void *fdt, const char *path)
{
      const char *end = path + strlen(path);
      const char *p = path;
      int offset = 0;

      CHECK_HEADER(fdt);

      if (*path != '/')
            return -FDT_ERR_BADPATH;

      while (*p) {
            const char *q;

            while (*p == '/')
                  p++;
            if (! *p)
                  return offset;
            q = strchr(p, '/');
            if (! q)
                  q = end;

            offset = fdt_subnode_offset_namelen(fdt, offset, p, q-p);
            if (offset < 0)
                  return offset;

            p = q;
      }

      return offset;
}

const char *fdt_get_name(const void *fdt, int nodeoffset, int *len)
{
      const struct fdt_node_header *nh;
      int err;

      if ((err = fdt_check_header(fdt)) != 0)
            goto fail;

      err = -FDT_ERR_BADOFFSET;
      nh = fdt_offset_ptr(fdt, nodeoffset, sizeof(*nh));
      if (!nh || (fdt32_to_cpu(nh->tag) != FDT_BEGIN_NODE))
            goto fail;

      if (len)
            *len = strlen(nh->name);

      return nh->name;

 fail:
      if (len)
            *len = err;
      return NULL;
}

const struct fdt_property *fdt_get_property(const void *fdt,
                                  int nodeoffset,
                                  const char *name, int *lenp)
{
      uint32_t tag;
      const struct fdt_property *prop;
      int namestroff;
      int offset, nextoffset;
      int err;

      if ((err = fdt_check_header(fdt)) != 0)
            goto fail;

      err = -FDT_ERR_BADOFFSET;
      if (nodeoffset % FDT_TAGSIZE)
            goto fail;

      tag = fdt_next_tag(fdt, nodeoffset, &nextoffset);
      if (tag != FDT_BEGIN_NODE)
            goto fail;

      do {
            offset = nextoffset;

            tag = fdt_next_tag(fdt, offset, &nextoffset);
            switch (tag) {
            case FDT_END:
                  err = -FDT_ERR_TRUNCATED;
                  goto fail;

            case FDT_BEGIN_NODE:
            case FDT_END_NODE:
            case FDT_NOP:
                  break;

            case FDT_PROP:
                  err = -FDT_ERR_BADSTRUCTURE;
                  prop = fdt_offset_ptr(fdt, offset, sizeof(*prop));
                  if (! prop)
                        goto fail;
                  namestroff = fdt32_to_cpu(prop->nameoff);
                  if (streq(fdt_string(fdt, namestroff), name)) {
                        /* Found it! */
                        int len = fdt32_to_cpu(prop->len);
                        prop = fdt_offset_ptr(fdt, offset,
                                          sizeof(*prop)+len);
                        if (! prop)
                              goto fail;

                        if (lenp)
                              *lenp = len;

                        return prop;
                  }
                  break;

            default:
                  err = -FDT_ERR_BADSTRUCTURE;
                  goto fail;
            }
      } while ((tag != FDT_BEGIN_NODE) && (tag != FDT_END_NODE));

      err = -FDT_ERR_NOTFOUND;
 fail:
      if (lenp)
            *lenp = err;
      return NULL;
}

const void *fdt_getprop(const void *fdt, int nodeoffset,
              const char *name, int *lenp)
{
      const struct fdt_property *prop;

      prop = fdt_get_property(fdt, nodeoffset, name, lenp);
      if (! prop)
            return NULL;

      return prop->data;
}

uint32_t fdt_get_phandle(const void *fdt, int nodeoffset)
{
      const uint32_t *php;
      int len;

      php = fdt_getprop(fdt, nodeoffset, "linux,phandle", &len);
      if (!php || (len != sizeof(*php)))
            return 0;

      return fdt32_to_cpu(*php);
}

int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen)
{
      uint32_t tag;
      int p = 0, overflow = 0;
      int offset, nextoffset, namelen;
      const char *name;

      CHECK_HEADER(fdt);

      tag = fdt_next_tag(fdt, 0, &nextoffset);
      if (tag != FDT_BEGIN_NODE)
            return -FDT_ERR_BADSTRUCTURE;

      if (buflen < 2)
            return -FDT_ERR_NOSPACE;
      buf[0] = '/';
      p = 1;

      while (nextoffset <= nodeoffset) {
            offset = nextoffset;
            tag = fdt_next_tag(fdt, offset, &nextoffset);
            switch (tag) {
            case FDT_END:
                  return -FDT_ERR_BADOFFSET;

            case FDT_BEGIN_NODE:
                  name = fdt_get_name(fdt, offset, &namelen);
                  if (!name)
                        return namelen;
                  if (overflow || ((p + namelen + 1) > buflen)) {
                        overflow++;
                        break;
                  }
                  memcpy(buf + p, name, namelen);
                  p += namelen;
                  buf[p++] = '/';
                  break;

            case FDT_END_NODE:
                  if (overflow) {
                        overflow--;
                        break;
                  }
                  do {
                        p--;
                  } while  (buf[p-1] != '/');
                  break;

            case FDT_PROP:
            case FDT_NOP:
                  break;

            default:
                  return -FDT_ERR_BADSTRUCTURE;
            }
      }

      if (overflow)
            return -FDT_ERR_NOSPACE;

      if (p > 1) /* special case so that root path is "/", not "" */
            p--;
      buf[p] = '\0';
      return p;
}

int fdt_supernode_atdepth_offset(const void *fdt, int nodeoffset,
                         int supernodedepth, int *nodedepth)
{
      int level = -1;
      uint32_t tag;
      int offset, nextoffset = 0;
      int supernodeoffset = -FDT_ERR_INTERNAL;

      CHECK_HEADER(fdt);

      if (supernodedepth < 0)
            return -FDT_ERR_NOTFOUND;

      do {
            offset = nextoffset;
            tag = fdt_next_tag(fdt, offset, &nextoffset);
            switch (tag) {
            case FDT_END:
                  return -FDT_ERR_BADOFFSET;

            case FDT_BEGIN_NODE:
                  level++;
                  if (level == supernodedepth)
                        supernodeoffset = offset;
                  break;

            case FDT_END_NODE:
                  level--;
                  break;

            case FDT_PROP:
            case FDT_NOP:
                  break;

            default:
                  return -FDT_ERR_BADSTRUCTURE;
            }
      } while (offset < nodeoffset);

      if (nodedepth)
            *nodedepth = level;

      if (supernodedepth > level)
            return -FDT_ERR_NOTFOUND;
      return supernodeoffset;
}

int fdt_node_depth(const void *fdt, int nodeoffset)
{
      int nodedepth;
      int err;

      err = fdt_supernode_atdepth_offset(fdt, nodeoffset, 0, &nodedepth);
      if (err)
            return (err < 0) ? err : -FDT_ERR_INTERNAL;
      return nodedepth;
}

int fdt_parent_offset(const void *fdt, int nodeoffset)
{
      int nodedepth = fdt_node_depth(fdt, nodeoffset);

      if (nodedepth < 0)
            return nodedepth;
      return fdt_supernode_atdepth_offset(fdt, nodeoffset,
                                  nodedepth - 1, NULL);
}

int fdt_node_offset_by_prop_value(const void *fdt, int startoffset,
                          const char *propname,
                          const void *propval, int proplen)
{
      uint32_t tag;
      int offset, nextoffset;
      const void *val;
      int len;

      CHECK_HEADER(fdt);

      if (startoffset >= 0) {
            tag = fdt_next_tag(fdt, startoffset, &nextoffset);
            if (tag != FDT_BEGIN_NODE)
                  return -FDT_ERR_BADOFFSET;
      } else {
            nextoffset = 0;
      }

      /* FIXME: The algorithm here is pretty horrible: we scan each
       * property of a node in fdt_getprop(), then if that didn't
       * find what we want, we scan over them again making our way
       * to the next node.  Still it's the easiest to implement
       * approach; performance can come later. */
      do {
            offset = nextoffset;
            tag = fdt_next_tag(fdt, offset, &nextoffset);

            switch (tag) {
            case FDT_BEGIN_NODE:
                  val = fdt_getprop(fdt, offset, propname, &len);
                  if (val
                      && (len == proplen)
                      && (memcmp(val, propval, len) == 0))
                        return offset;
                  break;

            case FDT_PROP:
            case FDT_END:
            case FDT_END_NODE:
            case FDT_NOP:
                  break;

            default:
                  return -FDT_ERR_BADSTRUCTURE;
            }
      } while (tag != FDT_END);

      return -FDT_ERR_NOTFOUND;
}

int fdt_node_offset_by_phandle(const void *fdt, uint32_t phandle)
{
      if ((phandle == 0) || (phandle == -1))
            return -FDT_ERR_BADPHANDLE;
      phandle = cpu_to_fdt32(phandle);
      return fdt_node_offset_by_prop_value(fdt, -1, "linux,phandle",
                                   &phandle, sizeof(phandle));
}

int _stringlist_contains(const void *strlist, int listlen, const char *str)
{
      int len = strlen(str);
      const void *p;

      while (listlen >= len) {
            if (memcmp(str, strlist, len+1) == 0)
                  return 1;
            p = memchr(strlist, '\0', listlen);
            if (!p)
                  return 0; /* malformed strlist.. */
            listlen -= (p-strlist) + 1;
            strlist = p + 1;
      }
      return 0;
}

int fdt_node_check_compatible(const void *fdt, int nodeoffset,
                        const char *compatible)
{
      const void *prop;
      int len;

      prop = fdt_getprop(fdt, nodeoffset, "compatible", &len);
      if (!prop)
            return len;
      if (_stringlist_contains(prop, len, compatible))
            return 0;
      else
            return 1;
}

int fdt_node_offset_by_compatible(const void *fdt, int startoffset,
                          const char *compatible)
{
      uint32_t tag;
      int offset, nextoffset;
      int err;

      CHECK_HEADER(fdt);

      if (startoffset >= 0) {
            tag = fdt_next_tag(fdt, startoffset, &nextoffset);
            if (tag != FDT_BEGIN_NODE)
                  return -FDT_ERR_BADOFFSET;
      } else {
            nextoffset = 0;
      }

      /* FIXME: The algorithm here is pretty horrible: we scan each
       * property of a node in fdt_node_check_compatible(), then if
       * that didn't find what we want, we scan over them again
       * making our way to the next node.  Still it's the easiest to
       * implement approach; performance can come later. */
      do {
            offset = nextoffset;
            tag = fdt_next_tag(fdt, offset, &nextoffset);

            switch (tag) {
            case FDT_BEGIN_NODE:
                  err = fdt_node_check_compatible(fdt, offset,
                                          compatible);
                  if ((err < 0)
                      && (err != -FDT_ERR_NOTFOUND))
                        return err;
                  else if (err == 0)
                        return offset;
                  break;

            case FDT_PROP:
            case FDT_END:
            case FDT_END_NODE:
            case FDT_NOP:
                  break;

            default:
                  return -FDT_ERR_BADSTRUCTURE;
            }
      } while (tag != FDT_END);

      return -FDT_ERR_NOTFOUND;
}

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