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 trucated 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
  73 struct 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 */
  81 static struct cmdline_mtd_partition *partitions;
  82
  83 /* the command line passed to mtdpart_setup() */
  84 static char *mtdparts;
  85 static char *cmdline;
  86 static 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  */
  96 static 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  */
 224 static 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  */
 308 static 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  */
 380 static int __init mtdpart_setup(char *s)
 381 {
 382         cmdline = s;
 383         return 1;
 384 }
 385
 386 __setup("mtdparts=", mtdpart_setup);
 387
 388 static struct mtd_part_parser cmdline_parser = {
 389         .owner = THIS_MODULE,
 390         .parse_fn = parse_cmdline_partitions,
 391         .name = "cmdlinepart",
 392 };
 393
 394 static int __init cmdline_parser_init(void)
 395 {
 396         if (mtdparts)
 397                 mtdpart_setup(mtdparts);
 398         return register_mtd_parser(&cmdline_parser);
 399 }
 400
 401 static void __exit cmdline_parser_exit(void)
 402 {
 403         deregister_mtd_parser(&cmdline_parser);
 404 }
 405
 406 module_init(cmdline_parser_init);
 407 module_exit(cmdline_parser_exit);
 408
 409 MODULE_PARM_DESC(mtdparts, "Partitioning specification");
 410 module_param(mtdparts, charp, 0);
 411
 412 MODULE_LICENSE("GPL");
 413 MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
 414 MODULE_DESCRIPTION("Command line configuration of MTD partitions");