drivers/mtd/cmdlinepart.c

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