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