drivers/mtd/cmdlinepart.c

   1 /*
   2  * $Id: cmdlinepart.c,v 1.19 2005/11/07 11:14:19 gleixner Exp $
   3  *
   4  * Read flash partition table from command line
   5  *
   6  * Copyright 2002 SYSGO Real-Time Solutions GmbH
   7  *
   8  * The format for the command line is as follows:
   9  *
  10  * mtdparts=<mtddef>[;<mtddef]
  11  * <mtddef>  := <mtd-id>:<partdef>[,<partdef>]
  12  * <partdef> := <size>[@offset][<name>][ro]
  13  * <mtd-id>  := unique name used in mapping driver/device (mtd->name)
  14  * <size>    := standard linux memsize OR "-" to denote all remaining space
  15  * <name>    := '(' NAME ')'
  16  *
  17  * Examples:
  18  *
  19  * 1 NOR Flash, with 1 single writable partition:
  20  * edb7312-nor:-
  21  *
  22  * 1 NOR Flash with 2 partitions, 1 NAND with one
  23  * edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
  24  */
  25
  26 #include <linux/kernel.h>
  27 #include <linux/slab.h>
  28
  29 #include <linux/mtd/mtd.h>
  30 #include <linux/mtd/partitions.h>
  31 #include <linux/bootmem.h>
  32
  33 /* error message prefix */
  34 #define ERRP "mtd: "
  35
  36 /* debug macro */
  37 #if 0
  38 #define dbg(x) do { printk("DEBUG-CMDLINE-PART: "); printk x; } while(0)
  39 #else
  40 #define dbg(x)
  41 #endif
  42
  43
  44 /* special size referring to all the remaining space in a partition */
  45 #define SIZE_REMAINING 0xffffffff
  46
  47 struct cmdline_mtd_partition {
  48         struct cmdline_mtd_partition *next;
  49         char *mtd_id;
  50         int num_parts;
  51         struct mtd_partition *parts;
  52 };
  53
  54 /* mtdpart_setup() parses into here */
  55 static struct cmdline_mtd_partition *partitions;
  56
  57 /* the command line passed to mtdpart_setupd() */
  58 static char *cmdline;
  59 static int cmdline_parsed = 0;
  60
  61 /*
  62  * Parse one partition definition for an MTD. Since there can be many
  63  * comma separated partition definitions, this function calls itself
  64  * recursively until no more partition definitions are found. Nice side
  65  * effect: the memory to keep the mtd_partition structs and the names
  66  * is allocated upon the last definition being found. At that point the
  67  * syntax has been verified ok.
  68  */
  69 static struct mtd_partition * newpart(char *s,
  70                                       char **retptr,
  71                                       int *num_parts,
  72                                       int this_part,
  73                                       unsigned char **extra_mem_ptr,
  74                                       int extra_mem_size)
  75 {
  76         struct mtd_partition *parts;
  77         unsigned long size;
  78         unsigned long offset = 0;
  79         char *name;
  80         int name_len;
  81         unsigned char *extra_mem;
  82         char delim;
  83         unsigned int mask_flags;
  84
  85         /* fetch the partition size */
  86         if (*s == '-')
  87         {       /* assign all remaining space to this partition */
  88                 size = SIZE_REMAINING;
  89                 s++;
  90         }
  91         else
  92         {
  93                 size = memparse(s, &s);
  94                 if (size < PAGE_SIZE)
  95                 {
  96                         printk(KERN_ERR ERRP "partition size too small (%lx)\n", size);
  97                         return NULL;
  98                 }
  99         }
 100
 101         /* fetch partition name and flags */
 102         mask_flags = 0; /* this is going to be a regular partition */
 103         delim = 0;
 104         /* check for offset */
 105         if (*s == '@')
 106         {
 107                 s++;
 108                 offset = memparse(s, &s);
 109         }
 110         /* now look for name */
 111         if (*s == '(')
 112         {
 113                 delim = ')';
 114         }
 115
 116         if (delim)
 117         {
 118                 char *p;
 119
 120                 name = ++s;
 121                 if ((p = strchr(name, delim)) == 0)
 122                 {
 123                         printk(KERN_ERR ERRP "no closing %c found in partition name\n", delim);
 124                         return NULL;
 125                 }
 126                 name_len = p - name;
 127                 s = p + 1;
 128         }
 129         else
 130         {
 131                 name = NULL;
 132                 name_len = 13; /* Partition_000 */
 133         }
 134
 135         /* record name length for memory allocation later */
 136         extra_mem_size += name_len + 1;
 137
 138         /* test for options */
 139         if (strncmp(s, "ro", 2) == 0)
 140         {
 141                 mask_flags |= MTD_WRITEABLE;
 142                 s += 2;
 143         }
 144
 145         /* test if more partitions are following */
 146         if (*s == ',')
 147         {
 148                 if (size == SIZE_REMAINING)
 149                 {
 150                         printk(KERN_ERR ERRP "no partitions allowed after a fill-up partition\n");
 151                         return NULL;
 152                 }
 153                 /* more partitions follow, parse them */
 154                 if ((parts = newpart(s + 1, &s, num_parts,
 155                                      this_part + 1, &extra_mem, extra_mem_size)) == 0)
 156                   return NULL;
 157         }
 158         else
 159         {       /* this is the last partition: allocate space for all */
 160                 int alloc_size;
 161
 162                 *num_parts = this_part + 1;
 163                 alloc_size = *num_parts * sizeof(struct mtd_partition) +
 164                              extra_mem_size;
 165                 parts = kmalloc(alloc_size, GFP_KERNEL);
 166                 if (!parts)
 167                 {
 168                         printk(KERN_ERR ERRP "out of memory\n");
 169                         return NULL;
 170                 }
 171                 memset(parts, 0, alloc_size);
 172                 extra_mem = (unsigned char *)(parts + *num_parts);
 173         }
 174         /* enter this partition (offset will be calculated later if it is zero at this point) */
 175         parts[this_part].size = size;
 176         parts[this_part].offset = offset;
 177         parts[this_part].mask_flags = mask_flags;
 178         if (name)
 179         {
 180                 strlcpy(extra_mem, name, name_len + 1);
 181         }
 182         else
 183         {
 184                 sprintf(extra_mem, "Partition_%03d", this_part);
 185         }
 186         parts[this_part].name = extra_mem;
 187         extra_mem += name_len + 1;
 188
 189         dbg(("partition %d: name <%s>, offset %x, size %x, mask flags %x\n",
 190              this_part,
 191              parts[this_part].name,
 192              parts[this_part].offset,
 193              parts[this_part].size,
 194              parts[this_part].mask_flags));
 195
 196         /* return (updated) pointer to extra_mem memory */
 197         if (extra_mem_ptr)
 198           *extra_mem_ptr = extra_mem;
 199
 200         /* return (updated) pointer command line string */
 201         *retptr = s;
 202
 203         /* return partition table */
 204         return parts;
 205 }
 206
 207 /*
 208  * Parse the command line.
 209  */
 210 static int mtdpart_setup_real(char *s)
 211 {
 212         cmdline_parsed = 1;
 213
 214         for( ; s != NULL; )
 215         {
 216                 struct cmdline_mtd_partition *this_mtd;
 217                 struct mtd_partition *parts;
 218                 int mtd_id_len;
 219                 int num_parts;
 220                 char *p, *mtd_id;
 221
 222                 mtd_id = s;
 223                 /* fetch <mtd-id> */
 224                 if (!(p = strchr(s, ':')))
 225                 {
 226                         printk(KERN_ERR ERRP "no mtd-id\n");
 227                         return 0;
 228                 }
 229                 mtd_id_len = p - mtd_id;
 230
 231                 dbg(("parsing <%s>\n", p+1));
 232
 233                 /*
 234                  * parse one mtd. have it reserve memory for the
 235                  * struct cmdline_mtd_partition and the mtd-id string.
 236                  */
 237                 parts = newpart(p + 1,          /* cmdline */
 238                                 &s,             /* out: updated cmdline ptr */
 239                                 &num_parts,     /* out: number of parts */
 240                                 0,              /* first partition */
 241                                 (unsigned char**)&this_mtd, /* out: extra mem */
 242                                 mtd_id_len + 1 + sizeof(*this_mtd) +
 243                                 sizeof(void*)-1 /*alignment*/);
 244                 if(!parts)
 245                 {
 246                         /*
 247                          * An error occurred. We're either:
 248                          * a) out of memory, or
 249                          * b) in the middle of the partition spec
 250                          * Either way, this mtd is hosed and we're
 251                          * unlikely to succeed in parsing any more
 252                          */
 253                          return 0;
 254                  }
 255
 256                 /* align this_mtd */
 257                 this_mtd = (struct cmdline_mtd_partition *)
 258                         ALIGN((unsigned long)this_mtd, sizeof(void*));
 259                 /* enter results */
 260                 this_mtd->parts = parts;
 261                 this_mtd->num_parts = num_parts;
 262                 this_mtd->mtd_id = (char*)(this_mtd + 1);
 263                 strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
 264
 265                 /* link into chain */
 266                 this_mtd->next = partitions;
 267                 partitions = this_mtd;
 268
 269                 dbg(("mtdid=<%s> num_parts=<%d>\n",
 270                      this_mtd->mtd_id, this_mtd->num_parts));
 271
 272
 273                 /* EOS - we're done */
 274                 if (*s == 0)
 275                         break;
 276
 277                 /* does another spec follow? */
 278                 if (*s != ';')
 279                 {
 280                         printk(KERN_ERR ERRP "bad character after partition (%c)\n", *s);
 281                         return 0;
 282                 }
 283                 s++;
 284         }
 285         return 1;
 286 }
 287
 288 /*
 289  * Main function to be called from the MTD mapping driver/device to
 290  * obtain the partitioning information. At this point the command line
 291  * arguments will actually be parsed and turned to struct mtd_partition
 292  * information. It returns partitions for the requested mtd device, or
 293  * the first one in the chain if a NULL mtd_id is passed in.
 294  */
 295 static int parse_cmdline_partitions(struct mtd_info *master,
 296                              struct mtd_partition **pparts,
 297                              unsigned long origin)
 298 {
 299         unsigned long offset;
 300         int i;
 301         struct cmdline_mtd_partition *part;
 302         char *mtd_id = master->name;
 303
 304         if(!cmdline)
 305                 return -EINVAL;
 306
 307         /* parse command line */
 308         if (!cmdline_parsed)
 309                 mtdpart_setup_real(cmdline);
 310
 311         for(part = partitions; part; part = part->next)
 312         {
 313                 if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
 314                 {
 315                         for(i = 0, offset = 0; i < part->num_parts; i++)
 316                         {
 317                                 if (!part->parts[i].offset)
 318                                   part->parts[i].offset = offset;
 319                                 else
 320                                   offset = part->parts[i].offset;
 321                                 if (part->parts[i].size == SIZE_REMAINING)
 322                                   part->parts[i].size = master->size - offset;
 323                                 if (offset + part->parts[i].size > master->size)
 324                                 {
 325                                         printk(KERN_WARNING ERRP
 326                                                "%s: partitioning exceeds flash size, truncating\n",
 327                                                part->mtd_id);
 328                                         part->parts[i].size = master->size - offset;
 329                                         part->num_parts = i;
 330                                 }
 331                                 offset += part->parts[i].size;
 332                         }
 333                         *pparts = part->parts;
 334                         return part->num_parts;
 335                 }
 336         }
 337         return -EINVAL;
 338 }
 339
 340
 341 /*
 342  * This is the handler for our kernel parameter, called from
 343  * main.c::checksetup(). Note that we can not yet kmalloc() anything,
 344  * so we only save the commandline for later processing.
 345  *
 346  * This function needs to be visible for bootloaders.
 347  */
 348 int mtdpart_setup(char *s)
 349 {
 350         cmdline = s;
 351         return 1;
 352 }
 353
 354 __setup("mtdparts=", mtdpart_setup);
 355
 356 static struct mtd_part_parser cmdline_parser = {
 357         .owner = THIS_MODULE,
 358         .parse_fn = parse_cmdline_partitions,
 359         .name = "cmdlinepart",
 360 };
 361
 362 static int __init cmdline_parser_init(void)
 363 {
 364         return register_mtd_parser(&cmdline_parser);
 365 }
 366
 367 module_init(cmdline_parser_init);
 368
 369 MODULE_LICENSE("GPL");
 370 MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
 371 MODULE_DESCRIPTION("Command line configuration of MTD partitions");