1 /* 2 * libfdt - Flat Device Tree manipulation 3 * Copyright (C) 2006 David Gibson, IBM Corporation. 4 * SPDX-License-Identifier: GPL-2.0+ BSD-2-Clause 5 */ 6 #include "libfdt_env.h" 7 8 #include <fdt.h> 9 #include <libfdt.h> 10 11 #include "libfdt_internal.h" 12 13 static int _fdt_sw_check_header(void *fdt) 14 { 15 if (fdt_magic(fdt) != FDT_SW_MAGIC) 16 return -FDT_ERR_BADMAGIC; 17 /* FIXME: should check more details about the header state */ 18 return 0; 19 } 20 21 #define FDT_SW_CHECK_HEADER(fdt) \ 22 { \ 23 int err; \ 24 if ((err = _fdt_sw_check_header(fdt)) != 0) \ 25 return err; \ 26 } 27 28 static void *_fdt_grab_space(void *fdt, size_t len) 29 { 30 int offset = fdt_size_dt_struct(fdt); 31 int spaceleft; 32 33 spaceleft = fdt_totalsize(fdt) - fdt_off_dt_struct(fdt) 34 - fdt_size_dt_strings(fdt); 35 36 if ((offset + len < offset) || (offset + len > spaceleft)) 37 return NULL; 38 39 fdt_set_size_dt_struct(fdt, offset + len); 40 return _fdt_offset_ptr_w(fdt, offset); 41 } 42 43 int fdt_create(void *buf, int bufsize) 44 { 45 void *fdt = buf; 46 47 if (bufsize < sizeof(struct fdt_header)) 48 return -FDT_ERR_NOSPACE; 49 50 memset(buf, 0, bufsize); 51 52 fdt_set_magic(fdt, FDT_SW_MAGIC); 53 fdt_set_version(fdt, FDT_LAST_SUPPORTED_VERSION); 54 fdt_set_last_comp_version(fdt, FDT_FIRST_SUPPORTED_VERSION); 55 fdt_set_totalsize(fdt, bufsize); 56 57 fdt_set_off_mem_rsvmap(fdt, FDT_ALIGN(sizeof(struct fdt_header), 58 sizeof(struct fdt_reserve_entry))); 59 fdt_set_off_dt_struct(fdt, fdt_off_mem_rsvmap(fdt)); 60 fdt_set_off_dt_strings(fdt, bufsize); 61 62 return 0; 63 } 64 65 int fdt_resize(void *fdt, void *buf, int bufsize) 66 { 67 size_t headsize, tailsize; 68 char *oldtail, *newtail; 69 70 FDT_SW_CHECK_HEADER(fdt); 71 72 headsize = fdt_off_dt_struct(fdt); 73 tailsize = fdt_size_dt_strings(fdt); 74 75 if ((headsize + tailsize) > bufsize) 76 return -FDT_ERR_NOSPACE; 77 78 oldtail = (char *)fdt + fdt_totalsize(fdt) - tailsize; 79 newtail = (char *)buf + bufsize - tailsize; 80 81 /* Two cases to avoid clobbering data if the old and new 82 * buffers partially overlap */ 83 if (buf <= fdt) { 84 memmove(buf, fdt, headsize); 85 memmove(newtail, oldtail, tailsize); 86 } else { 87 memmove(newtail, oldtail, tailsize); 88 memmove(buf, fdt, headsize); 89 } 90 91 fdt_set_off_dt_strings(buf, bufsize); 92 fdt_set_totalsize(buf, bufsize); 93 94 return 0; 95 } 96 97 int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size) 98 { 99 struct fdt_reserve_entry *re; 100 int offset; 101 102 FDT_SW_CHECK_HEADER(fdt); 103 104 if (fdt_size_dt_struct(fdt)) 105 return -FDT_ERR_BADSTATE; 106 107 offset = fdt_off_dt_struct(fdt); 108 if ((offset + sizeof(*re)) > fdt_totalsize(fdt)) 109 return -FDT_ERR_NOSPACE; 110 111 re = (struct fdt_reserve_entry *)((char *)fdt + offset); 112 re->address = cpu_to_fdt64(addr); 113 re->size = cpu_to_fdt64(size); 114 115 fdt_set_off_dt_struct(fdt, offset + sizeof(*re)); 116 117 return 0; 118 } 119 120 int fdt_finish_reservemap(void *fdt) 121 { 122 return fdt_add_reservemap_entry(fdt, 0, 0); 123 } 124 125 int fdt_begin_node(void *fdt, const char *name) 126 { 127 struct fdt_node_header *nh; 128 int namelen = strlen(name) + 1; 129 130 FDT_SW_CHECK_HEADER(fdt); 131 132 nh = _fdt_grab_space(fdt, sizeof(*nh) + FDT_TAGALIGN(namelen)); 133 if (! nh) 134 return -FDT_ERR_NOSPACE; 135 136 nh->tag = cpu_to_fdt32(FDT_BEGIN_NODE); 137 memcpy(nh->name, name, namelen); 138 return 0; 139 } 140 141 int fdt_end_node(void *fdt) 142 { 143 fdt32_t *en; 144 145 FDT_SW_CHECK_HEADER(fdt); 146 147 en = _fdt_grab_space(fdt, FDT_TAGSIZE); 148 if (! en) 149 return -FDT_ERR_NOSPACE; 150 151 *en = cpu_to_fdt32(FDT_END_NODE); 152 return 0; 153 } 154 155 static int _fdt_find_add_string(void *fdt, const char *s) 156 { 157 char *strtab = (char *)fdt + fdt_totalsize(fdt); 158 const char *p; 159 int strtabsize = fdt_size_dt_strings(fdt); 160 int len = strlen(s) + 1; 161 int struct_top, offset; 162 163 p = _fdt_find_string(strtab - strtabsize, strtabsize, s); 164 if (p) 165 return p - strtab; 166 167 /* Add it */ 168 offset = -strtabsize - len; 169 struct_top = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt); 170 if (fdt_totalsize(fdt) + offset < struct_top) 171 return 0; /* no more room :( */ 172 173 memcpy(strtab + offset, s, len); 174 fdt_set_size_dt_strings(fdt, strtabsize + len); 175 return offset; 176 } 177 178 int fdt_property(void *fdt, const char *name, const void *val, int len) 179 { 180 struct fdt_property *prop; 181 int nameoff; 182 183 FDT_SW_CHECK_HEADER(fdt); 184 185 nameoff = _fdt_find_add_string(fdt, name); 186 if (nameoff == 0) 187 return -FDT_ERR_NOSPACE; 188 189 prop = _fdt_grab_space(fdt, sizeof(*prop) + FDT_TAGALIGN(len)); 190 if (! prop) 191 return -FDT_ERR_NOSPACE; 192 193 prop->tag = cpu_to_fdt32(FDT_PROP); 194 prop->nameoff = cpu_to_fdt32(nameoff); 195 prop->len = cpu_to_fdt32(len); 196 memcpy(prop->data, val, len); 197 return 0; 198 } 199 200 int fdt_finish(void *fdt) 201 { 202 char *p = (char *)fdt; 203 fdt32_t *end; 204 int oldstroffset, newstroffset; 205 uint32_t tag; 206 int offset, nextoffset; 207 208 FDT_SW_CHECK_HEADER(fdt); 209 210 /* Add terminator */ 211 end = _fdt_grab_space(fdt, sizeof(*end)); 212 if (! end) 213 return -FDT_ERR_NOSPACE; 214 *end = cpu_to_fdt32(FDT_END); 215 216 /* Relocate the string table */ 217 oldstroffset = fdt_totalsize(fdt) - fdt_size_dt_strings(fdt); 218 newstroffset = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt); 219 memmove(p + newstroffset, p + oldstroffset, fdt_size_dt_strings(fdt)); 220 fdt_set_off_dt_strings(fdt, newstroffset); 221 222 /* Walk the structure, correcting string offsets */ 223 offset = 0; 224 while ((tag = fdt_next_tag(fdt, offset, &nextoffset)) != FDT_END) { 225 if (tag == FDT_PROP) { 226 struct fdt_property *prop = 227 _fdt_offset_ptr_w(fdt, offset); 228 int nameoff; 229 230 nameoff = fdt32_to_cpu(prop->nameoff); 231 nameoff += fdt_size_dt_strings(fdt); 232 prop->nameoff = cpu_to_fdt32(nameoff); 233 } 234 offset = nextoffset; 235 } 236 if (nextoffset < 0) 237 return nextoffset; 238 239 /* Finally, adjust the header */ 240 fdt_set_totalsize(fdt, newstroffset + fdt_size_dt_strings(fdt)); 241 fdt_set_magic(fdt, FDT_MAGIC); 242 return 0; 243 } 244