/*
 * libfdt - Flat Device Tree manipulation
 * Copyright (C) 2006 David Gibson, IBM Corporation.
 * SPDX-License-Identifier:     GPL-2.0+ BSD-2-Clause
 */
#include <libfdt_env.h>

#ifndef USE_HOSTCC
#include <fdt.h>
#include <libfdt.h>
#else
#include "fdt_host.h"
#endif

#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;
}