1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Read flash partition table from command line 4 * 5 * Copyright © 2002 SYSGO Real-Time Solutions GmbH 6 * Copyright © 2002-2010 David Woodhouse <dwmw2@infradead.org> 7 * 8 * The format for the command line is as follows: 9 * 10 * mtdparts=<mtddef>[;<mtddef] 11 * <mtddef> := <mtd-id>:<partdef>[,<partdef>] 12 * <partdef> := <size>[@<offset>][<name>][ro][lk][slc] 13 * <mtd-id> := unique name used in mapping driver/device (mtd->name) 14 * <size> := standard linux memsize OR "-" to denote all remaining space 15 * size is automatically truncated at end of device 16 * if specified or truncated size is 0 the part is skipped 17 * <offset> := standard linux memsize 18 * if omitted the part will immediately follow the previous part 19 * or 0 if the first part 20 * <name> := '(' NAME ')' 21 * NAME will appear in /proc/mtd 22 * 23 * <size> and <offset> can be specified such that the parts are out of order 24 * in physical memory and may even overlap. 25 * 26 * The parts are assigned MTD numbers in the order they are specified in the 27 * command line regardless of their order in physical memory. 28 * 29 * Examples: 30 * 31 * 1 NOR Flash, with 1 single writable partition: 32 * edb7312-nor:- 33 * 34 * 1 NOR Flash with 2 partitions, 1 NAND with one 35 * edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home) 36 */ 37 38 #define pr_fmt(fmt) "mtd: " fmt 39 40 #include <linux/kernel.h> 41 #include <linux/slab.h> 42 #include <linux/mtd/mtd.h> 43 #include <linux/mtd/partitions.h> 44 #include <linux/module.h> 45 #include <linux/err.h> 46 47 /* special size referring to all the remaining space in a partition */ 48 #define SIZE_REMAINING ULLONG_MAX 49 #define OFFSET_CONTINUOUS ULLONG_MAX 50 51 struct cmdline_mtd_partition { 52 struct cmdline_mtd_partition *next; 53 char *mtd_id; 54 int num_parts; 55 struct mtd_partition *parts; 56 }; 57 58 /* mtdpart_setup() parses into here */ 59 static struct cmdline_mtd_partition *partitions; 60 61 /* the command line passed to mtdpart_setup() */ 62 static char *mtdparts; 63 static char *cmdline; 64 static int cmdline_parsed; 65 66 /* 67 * Parse one partition definition for an MTD. Since there can be many 68 * comma separated partition definitions, this function calls itself 69 * recursively until no more partition definitions are found. Nice side 70 * effect: the memory to keep the mtd_partition structs and the names 71 * is allocated upon the last definition being found. At that point the 72 * syntax has been verified ok. 73 */ 74 static struct mtd_partition * newpart(char *s, 75 char **retptr, 76 int *num_parts, 77 int this_part, 78 unsigned char **extra_mem_ptr, 79 int extra_mem_size) 80 { 81 struct mtd_partition *parts; 82 unsigned long long size, offset = OFFSET_CONTINUOUS; 83 char *name; 84 int name_len; 85 unsigned char *extra_mem; 86 char delim; 87 unsigned int mask_flags, add_flags; 88 89 /* fetch the partition size */ 90 if (*s == '-') { 91 /* assign all remaining space to this partition */ 92 size = SIZE_REMAINING; 93 s++; 94 } else { 95 size = memparse(s, &s); 96 if (!size) { 97 pr_err("partition has size 0\n"); 98 return ERR_PTR(-EINVAL); 99 } 100 } 101 102 /* fetch partition name and flags */ 103 mask_flags = 0; /* this is going to be a regular partition */ 104 add_flags = 0; 105 delim = 0; 106 107 /* check for offset */ 108 if (*s == '@') { 109 s++; 110 offset = memparse(s, &s); 111 } 112 113 /* now look for name */ 114 if (*s == '(') 115 delim = ')'; 116 117 if (delim) { 118 char *p; 119 120 name = ++s; 121 p = strchr(name, delim); 122 if (!p) { 123 pr_err("no closing %c found in partition name\n", delim); 124 return ERR_PTR(-EINVAL); 125 } 126 name_len = p - name; 127 s = p + 1; 128 } else { 129 name = NULL; 130 name_len = 13; /* Partition_000 */ 131 } 132 133 /* record name length for memory allocation later */ 134 extra_mem_size += name_len + 1; 135 136 /* test for options */ 137 if (strncmp(s, "ro", 2) == 0) { 138 mask_flags |= MTD_WRITEABLE; 139 s += 2; 140 } 141 142 /* if lk is found do NOT unlock the MTD partition*/ 143 if (strncmp(s, "lk", 2) == 0) { 144 mask_flags |= MTD_POWERUP_LOCK; 145 s += 2; 146 } 147 148 /* if slc is found use emulated SLC mode on this partition*/ 149 if (!strncmp(s, "slc", 3)) { 150 add_flags |= MTD_SLC_ON_MLC_EMULATION; 151 s += 3; 152 } 153 154 /* test if more partitions are following */ 155 if (*s == ',') { 156 if (size == SIZE_REMAINING) { 157 pr_err("no partitions allowed after a fill-up partition\n"); 158 return ERR_PTR(-EINVAL); 159 } 160 /* more partitions follow, parse them */ 161 parts = newpart(s + 1, &s, num_parts, this_part + 1, 162 &extra_mem, extra_mem_size); 163 if (IS_ERR(parts)) 164 return parts; 165 } else { 166 /* this is the last partition: allocate space for all */ 167 int alloc_size; 168 169 *num_parts = this_part + 1; 170 alloc_size = *num_parts * sizeof(struct mtd_partition) + 171 extra_mem_size; 172 173 parts = kzalloc(alloc_size, GFP_KERNEL); 174 if (!parts) 175 return ERR_PTR(-ENOMEM); 176 extra_mem = (unsigned char *)(parts + *num_parts); 177 } 178 179 /* 180 * enter this partition (offset will be calculated later if it is 181 * OFFSET_CONTINUOUS at this point) 182 */ 183 parts[this_part].size = size; 184 parts[this_part].offset = offset; 185 parts[this_part].mask_flags = mask_flags; 186 parts[this_part].add_flags = add_flags; 187 if (name) 188 strscpy(extra_mem, name, name_len + 1); 189 else 190 sprintf(extra_mem, "Partition_%03d", this_part); 191 parts[this_part].name = extra_mem; 192 extra_mem += name_len + 1; 193 194 pr_debug("partition %d: name <%s>, offset %llx, size %llx, mask flags %x\n", 195 this_part, parts[this_part].name, parts[this_part].offset, 196 parts[this_part].size, parts[this_part].mask_flags); 197 198 /* return (updated) pointer to extra_mem memory */ 199 if (extra_mem_ptr) 200 *extra_mem_ptr = extra_mem; 201 202 /* return (updated) pointer command line string */ 203 *retptr = s; 204 205 /* return partition table */ 206 return parts; 207 } 208 209 /* 210 * Parse the command line. 211 */ 212 static int mtdpart_setup_real(char *s) 213 { 214 cmdline_parsed = 1; 215 216 for( ; s != NULL; ) 217 { 218 struct cmdline_mtd_partition *this_mtd; 219 struct mtd_partition *parts; 220 int mtd_id_len, num_parts; 221 char *p, *mtd_id, *semicol, *open_parenth; 222 223 /* 224 * Replace the first ';' by a NULL char so strrchr can work 225 * properly. 226 */ 227 semicol = strchr(s, ';'); 228 if (semicol) 229 *semicol = '\0'; 230 231 /* 232 * make sure that part-names with ":" will not be handled as 233 * part of the mtd-id with an ":" 234 */ 235 open_parenth = strchr(s, '('); 236 if (open_parenth) 237 *open_parenth = '\0'; 238 239 mtd_id = s; 240 241 /* 242 * fetch <mtd-id>. We use strrchr to ignore all ':' that could 243 * be present in the MTD name, only the last one is interpreted 244 * as an <mtd-id>/<part-definition> separator. 245 */ 246 p = strrchr(s, ':'); 247 248 /* Restore the '(' now. */ 249 if (open_parenth) 250 *open_parenth = '('; 251 252 /* Restore the ';' now. */ 253 if (semicol) 254 *semicol = ';'; 255 256 if (!p) { 257 pr_err("no mtd-id\n"); 258 return -EINVAL; 259 } 260 mtd_id_len = p - mtd_id; 261 262 pr_debug("parsing <%s>\n", p+1); 263 264 /* 265 * parse one mtd. have it reserve memory for the 266 * struct cmdline_mtd_partition and the mtd-id string. 267 */ 268 parts = newpart(p + 1, /* cmdline */ 269 &s, /* out: updated cmdline ptr */ 270 &num_parts, /* out: number of parts */ 271 0, /* first partition */ 272 (unsigned char**)&this_mtd, /* out: extra mem */ 273 mtd_id_len + 1 + sizeof(*this_mtd) + 274 sizeof(void*)-1 /*alignment*/); 275 if (IS_ERR(parts)) { 276 /* 277 * An error occurred. We're either: 278 * a) out of memory, or 279 * b) in the middle of the partition spec 280 * Either way, this mtd is hosed and we're 281 * unlikely to succeed in parsing any more 282 */ 283 return PTR_ERR(parts); 284 } 285 286 /* align this_mtd */ 287 this_mtd = (struct cmdline_mtd_partition *) 288 ALIGN((unsigned long)this_mtd, sizeof(void *)); 289 /* enter results */ 290 this_mtd->parts = parts; 291 this_mtd->num_parts = num_parts; 292 this_mtd->mtd_id = (char*)(this_mtd + 1); 293 strscpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1); 294 295 /* link into chain */ 296 this_mtd->next = partitions; 297 partitions = this_mtd; 298 299 pr_debug("mtdid=<%s> num_parts=<%d>\n", 300 this_mtd->mtd_id, this_mtd->num_parts); 301 302 303 /* EOS - we're done */ 304 if (*s == 0) 305 break; 306 307 /* does another spec follow? */ 308 if (*s != ';') { 309 pr_err("bad character after partition (%c)\n", *s); 310 return -EINVAL; 311 } 312 s++; 313 } 314 315 return 0; 316 } 317 318 /* 319 * Main function to be called from the MTD mapping driver/device to 320 * obtain the partitioning information. At this point the command line 321 * arguments will actually be parsed and turned to struct mtd_partition 322 * information. It returns partitions for the requested mtd device, or 323 * the first one in the chain if a NULL mtd_id is passed in. 324 */ 325 static int parse_cmdline_partitions(struct mtd_info *master, 326 const struct mtd_partition **pparts, 327 struct mtd_part_parser_data *data) 328 { 329 unsigned long long offset; 330 int i, err; 331 struct cmdline_mtd_partition *part; 332 const char *mtd_id = master->name; 333 334 /* parse command line */ 335 if (!cmdline_parsed) { 336 err = mtdpart_setup_real(cmdline); 337 if (err) 338 return err; 339 } 340 341 /* 342 * Search for the partition definition matching master->name. 343 * If master->name is not set, stop at first partition definition. 344 */ 345 for (part = partitions; part; part = part->next) { 346 if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id))) 347 break; 348 } 349 350 if (!part) 351 return 0; 352 353 for (i = 0, offset = 0; i < part->num_parts; i++) { 354 if (part->parts[i].offset == OFFSET_CONTINUOUS) 355 part->parts[i].offset = offset; 356 else 357 offset = part->parts[i].offset; 358 359 if (part->parts[i].size == SIZE_REMAINING) 360 part->parts[i].size = master->size - offset; 361 362 if (offset + part->parts[i].size > master->size) { 363 pr_warn("%s: partitioning exceeds flash size, truncating\n", 364 part->mtd_id); 365 part->parts[i].size = master->size - offset; 366 } 367 offset += part->parts[i].size; 368 369 if (part->parts[i].size == 0) { 370 pr_warn("%s: skipping zero sized partition\n", 371 part->mtd_id); 372 part->num_parts--; 373 memmove(&part->parts[i], &part->parts[i + 1], 374 sizeof(*part->parts) * (part->num_parts - i)); 375 i--; 376 } 377 } 378 379 *pparts = kmemdup(part->parts, sizeof(*part->parts) * part->num_parts, 380 GFP_KERNEL); 381 if (!*pparts) 382 return -ENOMEM; 383 384 return part->num_parts; 385 } 386 387 388 /* 389 * This is the handler for our kernel parameter, called from 390 * main.c::checksetup(). Note that we can not yet kmalloc() anything, 391 * so we only save the commandline for later processing. 392 * 393 * This function needs to be visible for bootloaders. 394 */ 395 static int __init mtdpart_setup(char *s) 396 { 397 cmdline = s; 398 return 1; 399 } 400 401 __setup("mtdparts=", mtdpart_setup); 402 403 static struct mtd_part_parser cmdline_parser = { 404 .parse_fn = parse_cmdline_partitions, 405 .name = "cmdlinepart", 406 }; 407 408 static int __init cmdline_parser_init(void) 409 { 410 if (mtdparts) 411 mtdpart_setup(mtdparts); 412 register_mtd_parser(&cmdline_parser); 413 return 0; 414 } 415 416 static void __exit cmdline_parser_exit(void) 417 { 418 deregister_mtd_parser(&cmdline_parser); 419 } 420 421 module_init(cmdline_parser_init); 422 module_exit(cmdline_parser_exit); 423 424 MODULE_PARM_DESC(mtdparts, "Partitioning specification"); 425 module_param(mtdparts, charp, 0); 426 427 MODULE_LICENSE("GPL"); 428 MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>"); 429 MODULE_DESCRIPTION("Command line configuration of MTD partitions"); 430