/*
 * 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"

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

#include "libfdt_internal.h"

static int _fdt_sw_check_header(void *fdt)
{
        if (fdt_magic(fdt) != FDT_SW_MAGIC)
                return -FDT_ERR_BADMAGIC;
        /* FIXME: should check more details about the header state */
        return 0;
}

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

static void *_fdt_grab_space(void *fdt, size_t len)
{
        int offset = fdt_size_dt_struct(fdt);
        int spaceleft;

        spaceleft = fdt_totalsize(fdt) - fdt_off_dt_struct(fdt)
                - fdt_size_dt_strings(fdt);

        if ((offset + len < offset) || (offset + len > spaceleft))
                return NULL;

        fdt_set_size_dt_struct(fdt, offset + len);
        return _fdt_offset_ptr_w(fdt, offset);
}

int fdt_create(void *buf, int bufsize)
{
        void *fdt = buf;

        if (bufsize < sizeof(struct fdt_header))
                return -FDT_ERR_NOSPACE;

        memset(buf, 0, bufsize);

        fdt_set_magic(fdt, FDT_SW_MAGIC);
        fdt_set_version(fdt, FDT_LAST_SUPPORTED_VERSION);
        fdt_set_last_comp_version(fdt, FDT_FIRST_SUPPORTED_VERSION);
        fdt_set_totalsize(fdt,  bufsize);

        fdt_set_off_mem_rsvmap(fdt, FDT_ALIGN(sizeof(struct fdt_header),
                                              sizeof(struct fdt_reserve_entry)));
        fdt_set_off_dt_struct(fdt, fdt_off_mem_rsvmap(fdt));
        fdt_set_off_dt_strings(fdt, bufsize);

        return 0;
}

int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size)
{
        struct fdt_reserve_entry *re;
        int offset;

        FDT_SW_CHECK_HEADER(fdt);

        if (fdt_size_dt_struct(fdt))
                return -FDT_ERR_BADSTATE;

        offset = fdt_off_dt_struct(fdt);
        if ((offset + sizeof(*re)) > fdt_totalsize(fdt))
                return -FDT_ERR_NOSPACE;

        re = (struct fdt_reserve_entry *)((char *)fdt + offset);
        re->address = cpu_to_fdt64(addr);
        re->size = cpu_to_fdt64(size);

        fdt_set_off_dt_struct(fdt, offset + sizeof(*re));

        return 0;
}

int fdt_finish_reservemap(void *fdt)
{
        return fdt_add_reservemap_entry(fdt, 0, 0);
}

int fdt_begin_node(void *fdt, const char *name)
{
        struct fdt_node_header *nh;
        int namelen = strlen(name) + 1;

        FDT_SW_CHECK_HEADER(fdt);

        nh = _fdt_grab_space(fdt, sizeof(*nh) + FDT_TAGALIGN(namelen));
        if (! nh)
                return -FDT_ERR_NOSPACE;

        nh->tag = cpu_to_fdt32(FDT_BEGIN_NODE);
        memcpy(nh->name, name, namelen);
        return 0;
}

int fdt_end_node(void *fdt)
{
        fdt32_t *en;

        FDT_SW_CHECK_HEADER(fdt);

        en = _fdt_grab_space(fdt, FDT_TAGSIZE);
        if (! en)
                return -FDT_ERR_NOSPACE;

        *en = cpu_to_fdt32(FDT_END_NODE);
        return 0;
}

static int _fdt_find_add_string(void *fdt, const char *s)
{
        char *strtab = (char *)fdt + fdt_totalsize(fdt);
        const char *p;
        int strtabsize = fdt_size_dt_strings(fdt);
        int len = strlen(s) + 1;
        int struct_top, offset;

        p = _fdt_find_string(strtab - strtabsize, strtabsize, s);
        if (p)
                return p - strtab;

        /* Add it */
        offset = -strtabsize - len;
        struct_top = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt);
        if (fdt_totalsize(fdt) + offset < struct_top)
                return 0; /* no more room :( */

        memcpy(strtab + offset, s, len);
        fdt_set_size_dt_strings(fdt, strtabsize + len);
        return offset;
}

int fdt_property(void *fdt, const char *name, const void *val, int len)
{
        struct fdt_property *prop;
        int nameoff;

        FDT_SW_CHECK_HEADER(fdt);

        nameoff = _fdt_find_add_string(fdt, name);
        if (nameoff == 0)
                return -FDT_ERR_NOSPACE;

        prop = _fdt_grab_space(fdt, sizeof(*prop) + FDT_TAGALIGN(len));
        if (! prop)
                return -FDT_ERR_NOSPACE;

        prop->tag = cpu_to_fdt32(FDT_PROP);
        prop->nameoff = cpu_to_fdt32(nameoff);
        prop->len = cpu_to_fdt32(len);
        memcpy(prop->data, val, len);
        return 0;
}

int fdt_finish(void *fdt)
{
        char *p = (char *)fdt;
        fdt32_t *end;
        int oldstroffset, newstroffset;
        uint32_t tag;
        int offset, nextoffset;

        FDT_SW_CHECK_HEADER(fdt);

        /* Add terminator */
        end = _fdt_grab_space(fdt, sizeof(*end));
        if (! end)
                return -FDT_ERR_NOSPACE;
        *end = cpu_to_fdt32(FDT_END);

        /* Relocate the string table */
        oldstroffset = fdt_totalsize(fdt) - fdt_size_dt_strings(fdt);
        newstroffset = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt);
        memmove(p + newstroffset, p + oldstroffset, fdt_size_dt_strings(fdt));
        fdt_set_off_dt_strings(fdt, newstroffset);

        /* Walk the structure, correcting string offsets */
        offset = 0;
        while ((tag = fdt_next_tag(fdt, offset, &nextoffset)) != FDT_END) {
                if (tag == FDT_PROP) {
                        struct fdt_property *prop =
                                _fdt_offset_ptr_w(fdt, offset);
                        int nameoff;

                        nameoff = fdt32_to_cpu(prop->nameoff);
                        nameoff += fdt_size_dt_strings(fdt);
                        prop->nameoff = cpu_to_fdt32(nameoff);
                }
                offset = nextoffset;
        }
        if (nextoffset < 0)
                return nextoffset;

        /* Finally, adjust the header */
        fdt_set_totalsize(fdt, newstroffset + fdt_size_dt_strings(fdt));
        fdt_set_magic(fdt, FDT_MAGIC);
        return 0;
}