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* libfdt - Flat Device Tree manipulation
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* Copyright (C) 2006 David Gibson, IBM Corporation.
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* SPDX-License-Identifier: GPL-2.0+ BSD-2-Clause
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#include "libfdt_env.h"
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#include "libfdt_internal.h"
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static int _fdt_sw_check_header(void *fdt)
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if (fdt_magic(fdt) != FDT_SW_MAGIC)
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return -FDT_ERR_BADMAGIC;
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/* FIXME: should check more details about the header state */
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#define FDT_SW_CHECK_HEADER(fdt) \
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if ((err = _fdt_sw_check_header(fdt)) != 0) \
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static void *_fdt_grab_space(void *fdt, size_t len)
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int offset = fdt_size_dt_struct(fdt);
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spaceleft = fdt_totalsize(fdt) - fdt_off_dt_struct(fdt)
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- fdt_size_dt_strings(fdt);
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if ((offset + len < offset) || (offset + len > spaceleft))
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fdt_set_size_dt_struct(fdt, offset + len);
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return _fdt_offset_ptr_w(fdt, offset);
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int fdt_create(void *buf, int bufsize)
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if (bufsize < sizeof(struct fdt_header))
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return -FDT_ERR_NOSPACE;
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memset(buf, 0, bufsize);
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fdt_set_magic(fdt, FDT_SW_MAGIC);
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fdt_set_version(fdt, FDT_LAST_SUPPORTED_VERSION);
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fdt_set_last_comp_version(fdt, FDT_FIRST_SUPPORTED_VERSION);
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fdt_set_totalsize(fdt, bufsize);
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fdt_set_off_mem_rsvmap(fdt, FDT_ALIGN(sizeof(struct fdt_header),
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sizeof(struct fdt_reserve_entry)));
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fdt_set_off_dt_struct(fdt, fdt_off_mem_rsvmap(fdt));
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fdt_set_off_dt_strings(fdt, bufsize);
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int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size)
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struct fdt_reserve_entry *re;
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FDT_SW_CHECK_HEADER(fdt);
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if (fdt_size_dt_struct(fdt))
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return -FDT_ERR_BADSTATE;
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offset = fdt_off_dt_struct(fdt);
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if ((offset + sizeof(*re)) > fdt_totalsize(fdt))
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return -FDT_ERR_NOSPACE;
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re = (struct fdt_reserve_entry *)((char *)fdt + offset);
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re->address = cpu_to_fdt64(addr);
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re->size = cpu_to_fdt64(size);
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fdt_set_off_dt_struct(fdt, offset + sizeof(*re));
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int fdt_finish_reservemap(void *fdt)
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return fdt_add_reservemap_entry(fdt, 0, 0);
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int fdt_begin_node(void *fdt, const char *name)
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struct fdt_node_header *nh;
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int namelen = strlen(name) + 1;
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FDT_SW_CHECK_HEADER(fdt);
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nh = _fdt_grab_space(fdt, sizeof(*nh) + FDT_TAGALIGN(namelen));
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return -FDT_ERR_NOSPACE;
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nh->tag = cpu_to_fdt32(FDT_BEGIN_NODE);
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memcpy(nh->name, name, namelen);
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int fdt_end_node(void *fdt)
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FDT_SW_CHECK_HEADER(fdt);
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en = _fdt_grab_space(fdt, FDT_TAGSIZE);
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return -FDT_ERR_NOSPACE;
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*en = cpu_to_fdt32(FDT_END_NODE);
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static int _fdt_find_add_string(void *fdt, const char *s)
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char *strtab = (char *)fdt + fdt_totalsize(fdt);
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int strtabsize = fdt_size_dt_strings(fdt);
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int len = strlen(s) + 1;
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int struct_top, offset;
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p = _fdt_find_string(strtab - strtabsize, strtabsize, s);
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offset = -strtabsize - len;
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struct_top = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt);
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if (fdt_totalsize(fdt) + offset < struct_top)
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return 0; /* no more room :( */
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memcpy(strtab + offset, s, len);
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fdt_set_size_dt_strings(fdt, strtabsize + len);
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int fdt_property(void *fdt, const char *name, const void *val, int len)
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struct fdt_property *prop;
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FDT_SW_CHECK_HEADER(fdt);
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nameoff = _fdt_find_add_string(fdt, name);
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return -FDT_ERR_NOSPACE;
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prop = _fdt_grab_space(fdt, sizeof(*prop) + FDT_TAGALIGN(len));
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return -FDT_ERR_NOSPACE;
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prop->tag = cpu_to_fdt32(FDT_PROP);
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prop->nameoff = cpu_to_fdt32(nameoff);
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prop->len = cpu_to_fdt32(len);
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memcpy(prop->data, val, len);
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int fdt_finish(void *fdt)
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char *p = (char *)fdt;
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int oldstroffset, newstroffset;
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int offset, nextoffset;
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FDT_SW_CHECK_HEADER(fdt);
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end = _fdt_grab_space(fdt, sizeof(*end));
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return -FDT_ERR_NOSPACE;
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*end = cpu_to_fdt32(FDT_END);
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/* Relocate the string table */
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oldstroffset = fdt_totalsize(fdt) - fdt_size_dt_strings(fdt);
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newstroffset = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt);
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memmove(p + newstroffset, p + oldstroffset, fdt_size_dt_strings(fdt));
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fdt_set_off_dt_strings(fdt, newstroffset);
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/* Walk the structure, correcting string offsets */
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while ((tag = fdt_next_tag(fdt, offset, &nextoffset)) != FDT_END) {
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if (tag == FDT_PROP) {
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struct fdt_property *prop =
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_fdt_offset_ptr_w(fdt, offset);
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nameoff = fdt32_to_cpu(prop->nameoff);
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nameoff += fdt_size_dt_strings(fdt);
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prop->nameoff = cpu_to_fdt32(nameoff);
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/* Finally, adjust the header */
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fdt_set_totalsize(fdt, newstroffset + fdt_size_dt_strings(fdt));
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fdt_set_magic(fdt, FDT_MAGIC);