rt-thread/components/drivers/fdt/libfdt/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;
}