1/* 2 * Read flash partition table from command line 3 * 4 * Copyright © 2002 SYSGO Real-Time Solutions GmbH 5 * Copyright © 2002-2010 David Woodhouse <dwmw2@infradead.org> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 20 * 21 * The format for the command line is as follows: 22 * 23 * mtdparts=<mtddef>[;<mtddef] 24 * <mtddef> := <mtd-id>:<partdef>[,<partdef>] 25 * <partdef> := <size>[@<offset>][<name>][ro][lk] 26 * <mtd-id> := unique name used in mapping driver/device (mtd->name) 27 * <size> := standard linux memsize OR "-" to denote all remaining space 28 * size is automatically truncated at end of device 29 * if specified or truncated size is 0 the part is skipped 30 * <offset> := standard linux memsize 31 * if omitted the part will immediately follow the previous part 32 * or 0 if the first part 33 * <name> := '(' NAME ')' 34 * NAME will appear in /proc/mtd 35 * 36 * <size> and <offset> can be specified such that the parts are out of order 37 * in physical memory and may even overlap. 38 * 39 * The parts are assigned MTD numbers in the order they are specified in the 40 * command line regardless of their order in physical memory. 41 * 42 * Examples: 43 * 44 * 1 NOR Flash, with 1 single writable partition: 45 * edb7312-nor:- 46 * 47 * 1 NOR Flash with 2 partitions, 1 NAND with one 48 * edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home) 49 */ 50 51#include <linux/kernel.h> 52#include <linux/slab.h> 53#include <linux/mtd/mtd.h> 54#include <linux/mtd/partitions.h> 55#include <linux/module.h> 56#include <linux/err.h> 57 58/* error message prefix */ 59#define ERRP "mtd: " 60 61/* debug macro */ 62#if 0 63#define dbg(x) do { printk("DEBUG-CMDLINE-PART: "); printk x; } while(0) 64#else 65#define dbg(x) 66#endif 67 68 69/* special size referring to all the remaining space in a partition */ 70#define SIZE_REMAINING ULLONG_MAX 71#define OFFSET_CONTINUOUS ULLONG_MAX 72 73struct cmdline_mtd_partition { 74 struct cmdline_mtd_partition *next; 75 char *mtd_id; 76 int num_parts; 77 struct mtd_partition *parts; 78}; 79 80/* mtdpart_setup() parses into here */ 81static struct cmdline_mtd_partition *partitions; 82 83/* the command line passed to mtdpart_setup() */ 84static char *mtdparts; 85static char *cmdline; 86static int cmdline_parsed; 87 88/* 89 * Parse one partition definition for an MTD. Since there can be many 90 * comma separated partition definitions, this function calls itself 91 * recursively until no more partition definitions are found. Nice side 92 * effect: the memory to keep the mtd_partition structs and the names 93 * is allocated upon the last definition being found. At that point the 94 * syntax has been verified ok. 95 */ 96static struct mtd_partition * newpart(char *s, 97 char **retptr, 98 int *num_parts, 99 int this_part, 100 unsigned char **extra_mem_ptr, 101 int extra_mem_size) 102{ 103 struct mtd_partition *parts; 104 unsigned long long size, offset = OFFSET_CONTINUOUS; 105 char *name; 106 int name_len; 107 unsigned char *extra_mem; 108 char delim; 109 unsigned int mask_flags; 110 111 /* fetch the partition size */ 112 if (*s == '-') { 113 /* assign all remaining space to this partition */ 114 size = SIZE_REMAINING; 115 s++; 116 } else { 117 size = memparse(s, &s); 118 if (size < PAGE_SIZE) { 119 printk(KERN_ERR ERRP "partition size too small (%llx)\n", 120 size); 121 return ERR_PTR(-EINVAL); 122 } 123 } 124 125 /* fetch partition name and flags */ 126 mask_flags = 0; /* this is going to be a regular partition */ 127 delim = 0; 128 129 /* check for offset */ 130 if (*s == '@') { 131 s++; 132 offset = memparse(s, &s); 133 } 134 135 /* now look for name */ 136 if (*s == '(') 137 delim = ')'; 138 139 if (delim) { 140 char *p; 141 142 name = ++s; 143 p = strchr(name, delim); 144 if (!p) { 145 printk(KERN_ERR ERRP "no closing %c found in partition name\n", delim); 146 return ERR_PTR(-EINVAL); 147 } 148 name_len = p - name; 149 s = p + 1; 150 } else { 151 name = NULL; 152 name_len = 13; /* Partition_000 */ 153 } 154 155 /* record name length for memory allocation later */ 156 extra_mem_size += name_len + 1; 157 158 /* test for options */ 159 if (strncmp(s, "ro", 2) == 0) { 160 mask_flags |= MTD_WRITEABLE; 161 s += 2; 162 } 163 164 /* if lk is found do NOT unlock the MTD partition*/ 165 if (strncmp(s, "lk", 2) == 0) { 166 mask_flags |= MTD_POWERUP_LOCK; 167 s += 2; 168 } 169 170 /* test if more partitions are following */ 171 if (*s == ',') { 172 if (size == SIZE_REMAINING) { 173 printk(KERN_ERR ERRP "no partitions allowed after a fill-up partition\n"); 174 return ERR_PTR(-EINVAL); 175 } 176 /* more partitions follow, parse them */ 177 parts = newpart(s + 1, &s, num_parts, this_part + 1, 178 &extra_mem, extra_mem_size); 179 if (IS_ERR(parts)) 180 return parts; 181 } else { 182 /* this is the last partition: allocate space for all */ 183 int alloc_size; 184 185 *num_parts = this_part + 1; 186 alloc_size = *num_parts * sizeof(struct mtd_partition) + 187 extra_mem_size; 188 189 parts = kzalloc(alloc_size, GFP_KERNEL); 190 if (!parts) 191 return ERR_PTR(-ENOMEM); 192 extra_mem = (unsigned char *)(parts + *num_parts); 193 } 194 195 /* enter this partition (offset will be calculated later if it is zero at this point) */ 196 parts[this_part].size = size; 197 parts[this_part].offset = offset; 198 parts[this_part].mask_flags = mask_flags; 199 if (name) 200 strlcpy(extra_mem, name, name_len + 1); 201 else 202 sprintf(extra_mem, "Partition_%03d", this_part); 203 parts[this_part].name = extra_mem; 204 extra_mem += name_len + 1; 205 206 dbg(("partition %d: name <%s>, offset %llx, size %llx, mask flags %x\n", 207 this_part, parts[this_part].name, parts[this_part].offset, 208 parts[this_part].size, parts[this_part].mask_flags)); 209 210 /* return (updated) pointer to extra_mem memory */ 211 if (extra_mem_ptr) 212 *extra_mem_ptr = extra_mem; 213 214 /* return (updated) pointer command line string */ 215 *retptr = s; 216 217 /* return partition table */ 218 return parts; 219} 220 221/* 222 * Parse the command line. 223 */ 224static int mtdpart_setup_real(char *s) 225{ 226 cmdline_parsed = 1; 227 228 for( ; s != NULL; ) 229 { 230 struct cmdline_mtd_partition *this_mtd; 231 struct mtd_partition *parts; 232 int mtd_id_len, num_parts; 233 char *p, *mtd_id; 234 235 mtd_id = s; 236 237 /* fetch <mtd-id> */ 238 p = strchr(s, ':'); 239 if (!p) { 240 printk(KERN_ERR ERRP "no mtd-id\n"); 241 return -EINVAL; 242 } 243 mtd_id_len = p - mtd_id; 244 245 dbg(("parsing <%s>\n", p+1)); 246 247 /* 248 * parse one mtd. have it reserve memory for the 249 * struct cmdline_mtd_partition and the mtd-id string. 250 */ 251 parts = newpart(p + 1, /* cmdline */ 252 &s, /* out: updated cmdline ptr */ 253 &num_parts, /* out: number of parts */ 254 0, /* first partition */ 255 (unsigned char**)&this_mtd, /* out: extra mem */ 256 mtd_id_len + 1 + sizeof(*this_mtd) + 257 sizeof(void*)-1 /*alignment*/); 258 if (IS_ERR(parts)) { 259 /* 260 * An error occurred. We're either: 261 * a) out of memory, or 262 * b) in the middle of the partition spec 263 * Either way, this mtd is hosed and we're 264 * unlikely to succeed in parsing any more 265 */ 266 return PTR_ERR(parts); 267 } 268 269 /* align this_mtd */ 270 this_mtd = (struct cmdline_mtd_partition *) 271 ALIGN((unsigned long)this_mtd, sizeof(void *)); 272 /* enter results */ 273 this_mtd->parts = parts; 274 this_mtd->num_parts = num_parts; 275 this_mtd->mtd_id = (char*)(this_mtd + 1); 276 strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1); 277 278 /* link into chain */ 279 this_mtd->next = partitions; 280 partitions = this_mtd; 281 282 dbg(("mtdid=<%s> num_parts=<%d>\n", 283 this_mtd->mtd_id, this_mtd->num_parts)); 284 285 286 /* EOS - we're done */ 287 if (*s == 0) 288 break; 289 290 /* does another spec follow? */ 291 if (*s != ';') { 292 printk(KERN_ERR ERRP "bad character after partition (%c)\n", *s); 293 return -EINVAL; 294 } 295 s++; 296 } 297 298 return 0; 299} 300 301/* 302 * Main function to be called from the MTD mapping driver/device to 303 * obtain the partitioning information. At this point the command line 304 * arguments will actually be parsed and turned to struct mtd_partition 305 * information. It returns partitions for the requested mtd device, or 306 * the first one in the chain if a NULL mtd_id is passed in. 307 */ 308static int parse_cmdline_partitions(struct mtd_info *master, 309 struct mtd_partition **pparts, 310 struct mtd_part_parser_data *data) 311{ 312 unsigned long long offset; 313 int i, err; 314 struct cmdline_mtd_partition *part; 315 const char *mtd_id = master->name; 316 317 /* parse command line */ 318 if (!cmdline_parsed) { 319 err = mtdpart_setup_real(cmdline); 320 if (err) 321 return err; 322 } 323 324 /* 325 * Search for the partition definition matching master->name. 326 * If master->name is not set, stop at first partition definition. 327 */ 328 for (part = partitions; part; part = part->next) { 329 if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id))) 330 break; 331 } 332 333 if (!part) 334 return 0; 335 336 for (i = 0, offset = 0; i < part->num_parts; i++) { 337 if (part->parts[i].offset == OFFSET_CONTINUOUS) 338 part->parts[i].offset = offset; 339 else 340 offset = part->parts[i].offset; 341 342 if (part->parts[i].size == SIZE_REMAINING) 343 part->parts[i].size = master->size - offset; 344 345 if (offset + part->parts[i].size > master->size) { 346 printk(KERN_WARNING ERRP 347 "%s: partitioning exceeds flash size, truncating\n", 348 part->mtd_id); 349 part->parts[i].size = master->size - offset; 350 } 351 offset += part->parts[i].size; 352 353 if (part->parts[i].size == 0) { 354 printk(KERN_WARNING ERRP 355 "%s: skipping zero sized partition\n", 356 part->mtd_id); 357 part->num_parts--; 358 memmove(&part->parts[i], &part->parts[i + 1], 359 sizeof(*part->parts) * (part->num_parts - i)); 360 i--; 361 } 362 } 363 364 *pparts = kmemdup(part->parts, sizeof(*part->parts) * part->num_parts, 365 GFP_KERNEL); 366 if (!*pparts) 367 return -ENOMEM; 368 369 return part->num_parts; 370} 371 372 373/* 374 * This is the handler for our kernel parameter, called from 375 * main.c::checksetup(). Note that we can not yet kmalloc() anything, 376 * so we only save the commandline for later processing. 377 * 378 * This function needs to be visible for bootloaders. 379 */ 380static int __init mtdpart_setup(char *s) 381{ 382 cmdline = s; 383 return 1; 384} 385 386__setup("mtdparts=", mtdpart_setup); 387 388static struct mtd_part_parser cmdline_parser = { 389 .owner = THIS_MODULE, 390 .parse_fn = parse_cmdline_partitions, 391 .name = "cmdlinepart", 392}; 393 394static int __init cmdline_parser_init(void) 395{ 396 if (mtdparts) 397 mtdpart_setup(mtdparts); 398 register_mtd_parser(&cmdline_parser); 399 return 0; 400} 401 402static void __exit cmdline_parser_exit(void) 403{ 404 deregister_mtd_parser(&cmdline_parser); 405} 406 407module_init(cmdline_parser_init); 408module_exit(cmdline_parser_exit); 409 410MODULE_PARM_DESC(mtdparts, "Partitioning specification"); 411module_param(mtdparts, charp, 0); 412 413MODULE_LICENSE("GPL"); 414MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>"); 415MODULE_DESCRIPTION("Command line configuration of MTD partitions"); 416