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                 {
 192                         printk(KERN_ERR ERRP "out of memory\n");
 193                         return NULL;
 194                 }
 195                 extra_mem = (unsigned char *)(parts + *num_parts);
 196         }
 197         /* enter this partition (offset will be calculated later if it is zero at this point) */
 198         parts[this_part].size = size;
 199         parts[this_part].offset = offset;
 200         parts[this_part].mask_flags = mask_flags;
 201         if (name)
 202         {
 203                 strlcpy(extra_mem, name, name_len + 1);
 204         }
 205         else
 206         {
 207                 sprintf(extra_mem, "Partition_%03d", this_part);
 208         }
 209         parts[this_part].name = extra_mem;
 210         extra_mem += name_len + 1;
 211
 212         dbg(("partition %d: name <%s>, offset %llx, size %llx, mask flags %x\n",
 213              this_part,
 214              parts[this_part].name,
 215              parts[this_part].offset,
 216              parts[this_part].size,
 217              parts[this_part].mask_flags));
 218
 219         /* return (updated) pointer to extra_mem memory */
 220         if (extra_mem_ptr)
 221           *extra_mem_ptr = extra_mem;
 222
 223         /* return (updated) pointer command line string */
 224         *retptr = s;
 225
 226         /* return partition table */
 227         return parts;
 228 }
 229
 230 /*
 231  * Parse the command line.
 232  */
 233 static int mtdpart_setup_real(char *s)
 234 {
 235         cmdline_parsed = 1;
 236
 237         for( ; s != NULL; )
 238         {
 239                 struct cmdline_mtd_partition *this_mtd;
 240                 struct mtd_partition *parts;
 241                 int mtd_id_len;
 242                 int num_parts;
 243                 char *p, *mtd_id;
 244
 245                 mtd_id = s;
 246                 /* fetch <mtd-id> */
 247                 if (!(p = strchr(s, ':')))
 248                 {
 249                         printk(KERN_ERR ERRP "no mtd-id\n");
 250                         return 0;
 251                 }
 252                 mtd_id_len = p - mtd_id;
 253
 254                 dbg(("parsing <%s>\n", p+1));
 255
 256                 /*
 257                  * parse one mtd. have it reserve memory for the
 258                  * struct cmdline_mtd_partition and the mtd-id string.
 259                  */
 260                 parts = newpart(p + 1,          /* cmdline */
 261                                 &s,             /* out: updated cmdline ptr */
 262                                 &num_parts,     /* out: number of parts */
 263                                 0,              /* first partition */
 264                                 (unsigned char**)&this_mtd, /* out: extra mem */
 265                                 mtd_id_len + 1 + sizeof(*this_mtd) +
 266                                 sizeof(void*)-1 /*alignment*/);
 267                 if(!parts)
 268                 {
 269                         /*
 270                          * An error occurred. We're either:
 271                          * a) out of memory, or
 272                          * b) in the middle of the partition spec
 273                          * Either way, this mtd is hosed and we're
 274                          * unlikely to succeed in parsing any more
 275                          */
 276                          return 0;
 277                  }
 278
 279                 /* align this_mtd */
 280                 this_mtd = (struct cmdline_mtd_partition *)
 281                         ALIGN((unsigned long)this_mtd, sizeof(void*));
 282                 /* enter results */
 283                 this_mtd->parts = parts;
 284                 this_mtd->num_parts = num_parts;
 285                 this_mtd->mtd_id = (char*)(this_mtd + 1);
 286                 strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
 287
 288                 /* link into chain */
 289                 this_mtd->next = partitions;
 290                 partitions = this_mtd;
 291
 292                 dbg(("mtdid=<%s> num_parts=<%d>\n",
 293                      this_mtd->mtd_id, this_mtd->num_parts));
 294
 295
 296                 /* EOS - we're done */
 297                 if (*s == 0)
 298                         break;
 299
 300                 /* does another spec follow? */
 301                 if (*s != ';')
 302                 {
 303                         printk(KERN_ERR ERRP "bad character after partition (%c)\n", *s);
 304                         return 0;
 305                 }
 306                 s++;
 307         }
 308         return 1;
 309 }
 310
 311 /*
 312  * Main function to be called from the MTD mapping driver/device to
 313  * obtain the partitioning information. At this point the command line
 314  * arguments will actually be parsed and turned to struct mtd_partition
 315  * information. It returns partitions for the requested mtd device, or
 316  * the first one in the chain if a NULL mtd_id is passed in.
 317  */
 318 static int parse_cmdline_partitions(struct mtd_info *master,
 319                              struct mtd_partition **pparts,
 320                              unsigned long origin)
 321 {
 322         unsigned long offset;
 323         int i;
 324         struct cmdline_mtd_partition *part;
 325         const char *mtd_id = master->name;
 326
 327         /* parse command line */
 328         if (!cmdline_parsed)
 329                 mtdpart_setup_real(cmdline);
 330
 331         for(part = partitions; part; part = part->next)
 332         {
 333                 if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
 334                 {
 335                         for(i = 0, offset = 0; i < part->num_parts; i++)
 336                         {
 337                                 if (part->parts[i].offset == OFFSET_CONTINUOUS)
 338                                   part->parts[i].offset = offset;
 339                                 else
 340                                   offset = part->parts[i].offset;
 341                                 if (part->parts[i].size == SIZE_REMAINING)
 342                                   part->parts[i].size = master->size - offset;
 343                                 if (offset + part->parts[i].size > master->size)
 344                                 {
 345                                         printk(KERN_WARNING ERRP
 346                                                "%s: partitioning exceeds flash size, truncating\n",
 347                                                part->mtd_id);
 348                                         part->parts[i].size = master->size - offset;
 349                                         part->num_parts = i;
 350                                 }
 351                                 offset += part->parts[i].size;
 352                         }
 353                         *pparts = kmemdup(part->parts,
 354                                         sizeof(*part->parts) * part->num_parts,
 355                                         GFP_KERNEL);
 356                         if (!*pparts)
 357                                 return -ENOMEM;
 358                         return part->num_parts;
 359                 }
 360         }
 361         return 0;
 362 }
 363
 364
 365 /*
 366  * This is the handler for our kernel parameter, called from
 367  * main.c::checksetup(). Note that we can not yet kmalloc() anything,
 368  * so we only save the commandline for later processing.
 369  *
 370  * This function needs to be visible for bootloaders.
 371  */
 372 static int mtdpart_setup(char *s)
 373 {
 374         cmdline = s;
 375         return 1;
 376 }
 377
 378 __setup("mtdparts=", mtdpart_setup);
 379
 380 static struct mtd_part_parser cmdline_parser = {
 381         .owner = THIS_MODULE,
 382         .parse_fn = parse_cmdline_partitions,
 383         .name = "cmdlinepart",
 384 };
 385
 386 static int __init cmdline_parser_init(void)
 387 {
 388         return register_mtd_parser(&cmdline_parser);
 389 }
 390
 391 module_init(cmdline_parser_init);
 392
 393 MODULE_LICENSE("GPL");
 394 MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
 395 MODULE_DESCRIPTION("Command line configuration of MTD partitions");