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 #include <linux/module.h>
  47
  48 /* error message prefix */
  49 #define ERRP "mtd: "
  50
  51 /* debug macro */
  52 #if 0
  53 #define dbg(x) do { printk("DEBUG-CMDLINE-PART: "); printk x; } while(0)
  54 #else
  55 #define dbg(x)
  56 #endif
  57
  58
  59 /* special size referring to all the remaining space in a partition */
  60 #define SIZE_REMAINING UINT_MAX
  61 #define OFFSET_CONTINUOUS UINT_MAX
  62
  63 struct cmdline_mtd_partition {
  64         struct cmdline_mtd_partition *next;
  65         char *mtd_id;
  66         int num_parts;
  67         struct mtd_partition *parts;
  68 };
  69
  70 /* mtdpart_setup() parses into here */
  71 static struct cmdline_mtd_partition *partitions;
  72
  73 /* the command line passed to mtdpart_setupd() */
  74 static char *cmdline;
  75 static int cmdline_parsed = 0;
  76
  77 /*
  78  * Parse one partition definition for an MTD. Since there can be many
  79  * comma separated partition definitions, this function calls itself
  80  * recursively until no more partition definitions are found. Nice side
  81  * effect: the memory to keep the mtd_partition structs and the names
  82  * is allocated upon the last definition being found. At that point the
  83  * syntax has been verified ok.
  84  */
  85 static struct mtd_partition * newpart(char *s,
  86                                       char **retptr,
  87                                       int *num_parts,
  88                                       int this_part,
  89                                       unsigned char **extra_mem_ptr,
  90                                       int extra_mem_size)
  91 {
  92         struct mtd_partition *parts;
  93         unsigned long size;
  94         unsigned long offset = OFFSET_CONTINUOUS;
  95         char *name;
  96         int name_len;
  97         unsigned char *extra_mem;
  98         char delim;
  99         unsigned int mask_flags;
 100
 101         /* fetch the partition size */
 102         if (*s == '-')
 103         {       /* assign all remaining space to this partition */
 104                 size = SIZE_REMAINING;
 105                 s++;
 106         }
 107         else
 108         {
 109                 size = memparse(s, &s);
 110                 if (size < PAGE_SIZE)
 111                 {
 112                         printk(KERN_ERR ERRP "partition size too small (%lx)\n", size);
 113                         return NULL;
 114                 }
 115         }
 116
 117         /* fetch partition name and flags */
 118         mask_flags = 0; /* this is going to be a regular partition */
 119         delim = 0;
 120         /* check for offset */
 121         if (*s == '@')
 122         {
 123                 s++;
 124                 offset = memparse(s, &s);
 125         }
 126         /* now look for name */
 127         if (*s == '(')
 128         {
 129                 delim = ')';
 130         }
 131
 132         if (delim)
 133         {
 134                 char *p;
 135
 136                 name = ++s;
 137                 p = strchr(name, delim);
 138                 if (!p)
 139                 {
 140                         printk(KERN_ERR ERRP "no closing %c found in partition name\n", delim);
 141                         return NULL;
 142                 }
 143                 name_len = p - name;
 144                 s = p + 1;
 145         }
 146         else
 147         {
 148                 name = NULL;
 149                 name_len = 13; /* Partition_000 */
 150         }
 151
 152         /* record name length for memory allocation later */
 153         extra_mem_size += name_len + 1;
 154
 155         /* test for options */
 156         if (strncmp(s, "ro", 2) == 0)
 157         {
 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         {
 165                 mask_flags |= MTD_POWERUP_LOCK;
 166                 s += 2;
 167         }
 168
 169         /* test if more partitions are following */
 170         if (*s == ',')
 171         {
 172                 if (size == SIZE_REMAINING)
 173                 {
 174                         printk(KERN_ERR ERRP "no partitions allowed after a fill-up partition\n");
 175                         return NULL;
 176                 }
 177                 /* more partitions follow, parse them */
 178                 parts = newpart(s + 1, &s, num_parts, this_part + 1,
 179                                 &extra_mem, extra_mem_size);
 180                 if (!parts)
 181                         return NULL;
 182         }
 183         else
 184         {       /* this is the last partition: allocate space for all */
 185                 int alloc_size;
 186
 187                 *num_parts = this_part + 1;
 188                 alloc_size = *num_parts * sizeof(struct mtd_partition) +
 189                              extra_mem_size;
 190                 parts = kzalloc(alloc_size, GFP_KERNEL);
 191                 if (!parts)
 192                 {
 193                         printk(KERN_ERR ERRP "out of memory\n");
 194                         return NULL;
 195                 }
 196                 extra_mem = (unsigned char *)(parts + *num_parts);
 197         }
 198         /* enter this partition (offset will be calculated later if it is zero at this point) */
 199         parts[this_part].size = size;
 200         parts[this_part].offset = offset;
 201         parts[this_part].mask_flags = mask_flags;
 202         if (name)
 203         {
 204                 strlcpy(extra_mem, name, name_len + 1);
 205         }
 206         else
 207         {
 208                 sprintf(extra_mem, "Partition_%03d", this_part);
 209         }
 210         parts[this_part].name = extra_mem;
 211         extra_mem += name_len + 1;
 212
 213         dbg(("partition %d: name <%s>, offset %llx, size %llx, mask flags %x\n",
 214              this_part,
 215              parts[this_part].name,
 216              parts[this_part].offset,
 217              parts[this_part].size,
 218              parts[this_part].mask_flags));
 219
 220         /* return (updated) pointer to extra_mem memory */
 221         if (extra_mem_ptr)
 222           *extra_mem_ptr = extra_mem;
 223
 224         /* return (updated) pointer command line string */
 225         *retptr = s;
 226
 227         /* return partition table */
 228         return parts;
 229 }
 230
 231 /*
 232  * Parse the command line.
 233  */
 234 static int mtdpart_setup_real(char *s)
 235 {
 236         cmdline_parsed = 1;
 237
 238         for( ; s != NULL; )
 239         {
 240                 struct cmdline_mtd_partition *this_mtd;
 241                 struct mtd_partition *parts;
 242                 int mtd_id_len;
 243                 int num_parts;
 244                 char *p, *mtd_id;
 245
 246                 mtd_id = s;
 247                 /* fetch <mtd-id> */
 248                 if (!(p = strchr(s, ':')))
 249                 {
 250                         printk(KERN_ERR ERRP "no mtd-id\n");
 251                         return 0;
 252                 }
 253                 mtd_id_len = p - mtd_id;
 254
 255                 dbg(("parsing <%s>\n", p+1));
 256
 257                 /*
 258                  * parse one mtd. have it reserve memory for the
 259                  * struct cmdline_mtd_partition and the mtd-id string.
 260                  */
 261                 parts = newpart(p + 1,          /* cmdline */
 262                                 &s,             /* out: updated cmdline ptr */
 263                                 &num_parts,     /* out: number of parts */
 264                                 0,              /* first partition */
 265                                 (unsigned char**)&this_mtd, /* out: extra mem */
 266                                 mtd_id_len + 1 + sizeof(*this_mtd) +
 267                                 sizeof(void*)-1 /*alignment*/);
 268                 if(!parts)
 269                 {
 270                         /*
 271                          * An error occurred. We're either:
 272                          * a) out of memory, or
 273                          * b) in the middle of the partition spec
 274                          * Either way, this mtd is hosed and we're
 275                          * unlikely to succeed in parsing any more
 276                          */
 277                          return 0;
 278                  }
 279
 280                 /* align this_mtd */
 281                 this_mtd = (struct cmdline_mtd_partition *)
 282                         ALIGN((unsigned long)this_mtd, sizeof(void*));
 283                 /* enter results */
 284                 this_mtd->parts = parts;
 285                 this_mtd->num_parts = num_parts;
 286                 this_mtd->mtd_id = (char*)(this_mtd + 1);
 287                 strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
 288
 289                 /* link into chain */
 290                 this_mtd->next = partitions;
 291                 partitions = this_mtd;
 292
 293                 dbg(("mtdid=<%s> num_parts=<%d>\n",
 294                      this_mtd->mtd_id, this_mtd->num_parts));
 295
 296
 297                 /* EOS - we're done */
 298                 if (*s == 0)
 299                         break;
 300
 301                 /* does another spec follow? */
 302                 if (*s != ';')
 303                 {
 304                         printk(KERN_ERR ERRP "bad character after partition (%c)\n", *s);
 305                         return 0;
 306                 }
 307                 s++;
 308         }
 309         return 1;
 310 }
 311
 312 /*
 313  * Main function to be called from the MTD mapping driver/device to
 314  * obtain the partitioning information. At this point the command line
 315  * arguments will actually be parsed and turned to struct mtd_partition
 316  * information. It returns partitions for the requested mtd device, or
 317  * the first one in the chain if a NULL mtd_id is passed in.
 318  */
 319 static int parse_cmdline_partitions(struct mtd_info *master,
 320                              struct mtd_partition **pparts,
 321                              unsigned long origin)
 322 {
 323         unsigned long offset;
 324         int i;
 325         struct cmdline_mtd_partition *part;
 326         const char *mtd_id = master->name;
 327
 328         /* parse command line */
 329         if (!cmdline_parsed)
 330                 mtdpart_setup_real(cmdline);
 331
 332         for(part = partitions; part; part = part->next)
 333         {
 334                 if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
 335                 {
 336                         for(i = 0, offset = 0; i < part->num_parts; i++)
 337                         {
 338                                 if (part->parts[i].offset == OFFSET_CONTINUOUS)
 339                                   part->parts[i].offset = offset;
 340                                 else
 341                                   offset = part->parts[i].offset;
 342                                 if (part->parts[i].size == SIZE_REMAINING)
 343                                   part->parts[i].size = master->size - offset;
 344                                 if (offset + part->parts[i].size > master->size)
 345                                 {
 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                                         part->num_parts = i;
 351                                 }
 352                                 offset += part->parts[i].size;
 353                         }
 354                         *pparts = kmemdup(part->parts,
 355                                         sizeof(*part->parts) * part->num_parts,
 356                                         GFP_KERNEL);
 357                         if (!*pparts)
 358                                 return -ENOMEM;
 359                         return part->num_parts;
 360                 }
 361         }
 362         return 0;
 363 }
 364
 365
 366 /*
 367  * This is the handler for our kernel parameter, called from
 368  * main.c::checksetup(). Note that we can not yet kmalloc() anything,
 369  * so we only save the commandline for later processing.
 370  *
 371  * This function needs to be visible for bootloaders.
 372  */
 373 static int mtdpart_setup(char *s)
 374 {
 375         cmdline = s;
 376         return 1;
 377 }
 378
 379 __setup("mtdparts=", mtdpart_setup);
 380
 381 static struct mtd_part_parser cmdline_parser = {
 382         .owner = THIS_MODULE,
 383         .parse_fn = parse_cmdline_partitions,
 384         .name = "cmdlinepart",
 385 };
 386
 387 static int __init cmdline_parser_init(void)
 388 {
 389         return register_mtd_parser(&cmdline_parser);
 390 }
 391
 392 module_init(cmdline_parser_init);
 393
 394 MODULE_LICENSE("GPL");
 395 MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
 396 MODULE_DESCRIPTION("Command line configuration of MTD partitions");