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