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         /*
 194          * enter this partition (offset will be calculated later if it is
 195          * OFFSET_CONTINUOUS at this point)
 196          */
 197         parts[this_part].size = size;
 198         parts[this_part].offset = offset;
 199         parts[this_part].mask_flags = mask_flags;
 200         if (name)
 201                 strlcpy(extra_mem, name, name_len + 1);
 202         else
 203                 sprintf(extra_mem, "Partition_%03d", this_part);
 204         parts[this_part].name = extra_mem;
 205         extra_mem += name_len + 1;
 206
 207         dbg(("partition %d: name <%s>, offset %llx, size %llx, mask flags %x\n",
 208              this_part, parts[this_part].name, parts[this_part].offset,
 209              parts[this_part].size, parts[this_part].mask_flags));
 210
 211         /* return (updated) pointer to extra_mem memory */
 212         if (extra_mem_ptr)
 213                 *extra_mem_ptr = extra_mem;
 214
 215         /* return (updated) pointer command line string */
 216         *retptr = s;
 217
 218         /* return partition table */
 219         return parts;
 220 }
 221
 222 /*
 223  * Parse the command line.
 224  */
 225 static int mtdpart_setup_real(char *s)
 226 {
 227         cmdline_parsed = 1;
 228
 229         for( ; s != NULL; )
 230         {
 231                 struct cmdline_mtd_partition *this_mtd;
 232                 struct mtd_partition *parts;
 233                 int mtd_id_len, num_parts;
 234                 char *p, *mtd_id;
 235
 236                 mtd_id = s;
 237
 238                 /* fetch <mtd-id> */
 239                 p = strchr(s, ':');
 240                 if (!p) {
 241                         pr_err("no mtd-id\n");
 242                         return -EINVAL;
 243                 }
 244                 mtd_id_len = p - mtd_id;
 245
 246                 dbg(("parsing <%s>\n", p+1));
 247
 248                 /*
 249                  * parse one mtd. have it reserve memory for the
 250                  * struct cmdline_mtd_partition and the mtd-id string.
 251                  */
 252                 parts = newpart(p + 1,          /* cmdline */
 253                                 &s,             /* out: updated cmdline ptr */
 254                                 &num_parts,     /* out: number of parts */
 255                                 0,              /* first partition */
 256                                 (unsigned char**)&this_mtd, /* out: extra mem */
 257                                 mtd_id_len + 1 + sizeof(*this_mtd) +
 258                                 sizeof(void*)-1 /*alignment*/);
 259                 if (IS_ERR(parts)) {
 260                         /*
 261                          * An error occurred. We're either:
 262                          * a) out of memory, or
 263                          * b) in the middle of the partition spec
 264                          * Either way, this mtd is hosed and we're
 265                          * unlikely to succeed in parsing any more
 266                          */
 267                          return PTR_ERR(parts);
 268                  }
 269
 270                 /* align this_mtd */
 271                 this_mtd = (struct cmdline_mtd_partition *)
 272                                 ALIGN((unsigned long)this_mtd, sizeof(void *));
 273                 /* enter results */
 274                 this_mtd->parts = parts;
 275                 this_mtd->num_parts = num_parts;
 276                 this_mtd->mtd_id = (char*)(this_mtd + 1);
 277                 strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
 278
 279                 /* link into chain */
 280                 this_mtd->next = partitions;
 281                 partitions = this_mtd;
 282
 283                 dbg(("mtdid=<%s> num_parts=<%d>\n",
 284                      this_mtd->mtd_id, this_mtd->num_parts));
 285
 286
 287                 /* EOS - we're done */
 288                 if (*s == 0)
 289                         break;
 290
 291                 /* does another spec follow? */
 292                 if (*s != ';') {
 293                         pr_err("bad character after partition (%c)\n", *s);
 294                         return -EINVAL;
 295                 }
 296                 s++;
 297         }
 298
 299         return 0;
 300 }
 301
 302 /*
 303  * Main function to be called from the MTD mapping driver/device to
 304  * obtain the partitioning information. At this point the command line
 305  * arguments will actually be parsed and turned to struct mtd_partition
 306  * information. It returns partitions for the requested mtd device, or
 307  * the first one in the chain if a NULL mtd_id is passed in.
 308  */
 309 static int parse_cmdline_partitions(struct mtd_info *master,
 310                                     const struct mtd_partition **pparts,
 311                                     struct mtd_part_parser_data *data)
 312 {
 313         unsigned long long offset;
 314         int i, err;
 315         struct cmdline_mtd_partition *part;
 316         const char *mtd_id = master->name;
 317
 318         /* parse command line */
 319         if (!cmdline_parsed) {
 320                 err = mtdpart_setup_real(cmdline);
 321                 if (err)
 322                         return err;
 323         }
 324
 325         /*
 326          * Search for the partition definition matching master->name.
 327          * If master->name is not set, stop at first partition definition.
 328          */
 329         for (part = partitions; part; part = part->next) {
 330                 if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
 331                         break;
 332         }
 333
 334         if (!part)
 335                 return 0;
 336
 337         for (i = 0, offset = 0; i < part->num_parts; i++) {
 338                 if (part->parts[i].offset == OFFSET_CONTINUOUS)
 339                         part->parts[i].offset = offset;
 340                 else
 341                         offset = part->parts[i].offset;
 342
 343                 if (part->parts[i].size == SIZE_REMAINING)
 344                         part->parts[i].size = master->size - offset;
 345
 346                 if (offset + part->parts[i].size > master->size) {
 347                         pr_warn("%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                         pr_warn("%s: skipping zero sized partition\n",
 355                                 part->mtd_id);
 356                         part->num_parts--;
 357                         memmove(&part->parts[i], &part->parts[i + 1],
 358                                 sizeof(*part->parts) * (part->num_parts - i));
 359                         i--;
 360                 }
 361         }
 362
 363         *pparts = kmemdup(part->parts, sizeof(*part->parts) * part->num_parts,
 364                           GFP_KERNEL);
 365         if (!*pparts)
 366                 return -ENOMEM;
 367
 368         return part->num_parts;
 369 }
 370
 371
 372 /*
 373  * This is the handler for our kernel parameter, called from
 374  * main.c::checksetup(). Note that we can not yet kmalloc() anything,
 375  * so we only save the commandline for later processing.
 376  *
 377  * This function needs to be visible for bootloaders.
 378  */
 379 static int __init mtdpart_setup(char *s)
 380 {
 381         cmdline = s;
 382         return 1;
 383 }
 384
 385 __setup("mtdparts=", mtdpart_setup);
 386
 387 static struct mtd_part_parser cmdline_parser = {
 388         .parse_fn = parse_cmdline_partitions,
 389         .name = "cmdlinepart",
 390 };
 391
 392 static int __init cmdline_parser_init(void)
 393 {
 394         if (mtdparts)
 395                 mtdpart_setup(mtdparts);
 396         register_mtd_parser(&cmdline_parser);
 397         return 0;
 398 }
 399
 400 static void __exit cmdline_parser_exit(void)
 401 {
 402         deregister_mtd_parser(&cmdline_parser);
 403 }
 404
 405 module_init(cmdline_parser_init);
 406 module_exit(cmdline_parser_exit);
 407
 408 MODULE_PARM_DESC(mtdparts, "Partitioning specification");
 409 module_param(mtdparts, charp, 0);
 410
 411 MODULE_LICENSE("GPL");
 412 MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
 413 MODULE_DESCRIPTION("Command line configuration of MTD partitions");