drivers/mtd/cmdlinepart.c

   1 /*
   2  * Read flash partition table from command line
   3  *
   4  * Copyright 2002 SYSGO Real-Time Solutions GmbH
   5  *
   6  * The format for the command line is as follows:
   7  *
   8  * mtdparts=<mtddef>[;<mtddef]
   9  * <mtddef>  := <mtd-id>:<partdef>[,<partdef>]
  10  *              where <mtd-id> is the name from the "cat /proc/mtd" command
  11  * <partdef> := <size>[@offset][<name>][ro][lk]
  12  * <mtd-id>  := unique name used in mapping driver/device (mtd->name)
  13  * <size>    := standard linux memsize OR "-" to denote all remaining space
  14  * <name>    := '(' NAME ')'
  15  *
  16  * Examples:
  17  *
  18  * 1 NOR Flash, with 1 single writable partition:
  19  * edb7312-nor:-
  20  *
  21  * 1 NOR Flash with 2 partitions, 1 NAND with one
  22  * edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
  23  */
  24
  25 #include <linux/kernel.h>
  26 #include <linux/slab.h>
  27
  28 #include <linux/mtd/mtd.h>
  29 #include <linux/mtd/partitions.h>
  30 #include <linux/bootmem.h>
  31
  32 /* error message prefix */
  33 #define ERRP "mtd: "
  34
  35 /* debug macro */
  36 #if 0
  37 #define dbg(x) do { printk("DEBUG-CMDLINE-PART: "); printk x; } while(0)
  38 #else
  39 #define dbg(x)
  40 #endif
  41
  42
  43 /* special size referring to all the remaining space in a partition */
  44 #define SIZE_REMAINING UINT_MAX
  45 #define OFFSET_CONTINUOUS UINT_MAX
  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 = OFFSET_CONTINUOUS;
  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                 p = strchr(name, delim);
 122                 if (!p)
 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         /* if lk is found do NOT unlock the MTD partition*/
 147         if (strncmp(s, "lk", 2) == 0)
 148         {
 149                 mask_flags |= MTD_POWERUP_LOCK;
 150                 s += 2;
 151         }
 152
 153         /* test if more partitions are following */
 154         if (*s == ',')
 155         {
 156                 if (size == SIZE_REMAINING)
 157                 {
 158                         printk(KERN_ERR ERRP "no partitions allowed after a fill-up partition\n");
 159                         return NULL;
 160                 }
 161                 /* more partitions follow, parse them */
 162                 parts = newpart(s + 1, &s, num_parts, this_part + 1,
 163                                 &extra_mem, extra_mem_size);
 164                 if (!parts)
 165                         return NULL;
 166         }
 167         else
 168         {       /* this is the last partition: allocate space for all */
 169                 int alloc_size;
 170
 171                 *num_parts = this_part + 1;
 172                 alloc_size = *num_parts * sizeof(struct mtd_partition) +
 173                              extra_mem_size;
 174                 parts = kzalloc(alloc_size, GFP_KERNEL);
 175                 if (!parts)
 176                 {
 177                         printk(KERN_ERR ERRP "out of memory\n");
 178                         return NULL;
 179                 }
 180                 extra_mem = (unsigned char *)(parts + *num_parts);
 181         }
 182         /* enter this partition (offset will be calculated later if it is zero at this point) */
 183         parts[this_part].size = size;
 184         parts[this_part].offset = offset;
 185         parts[this_part].mask_flags = mask_flags;
 186         if (name)
 187         {
 188                 strlcpy(extra_mem, name, name_len + 1);
 189         }
 190         else
 191         {
 192                 sprintf(extra_mem, "Partition_%03d", this_part);
 193         }
 194         parts[this_part].name = extra_mem;
 195         extra_mem += name_len + 1;
 196
 197         dbg(("partition %d: name <%s>, offset %x, size %x, mask flags %x\n",
 198              this_part,
 199              parts[this_part].name,
 200              parts[this_part].offset,
 201              parts[this_part].size,
 202              parts[this_part].mask_flags));
 203
 204         /* return (updated) pointer to extra_mem memory */
 205         if (extra_mem_ptr)
 206           *extra_mem_ptr = extra_mem;
 207
 208         /* return (updated) pointer command line string */
 209         *retptr = s;
 210
 211         /* return partition table */
 212         return parts;
 213 }
 214
 215 /*
 216  * Parse the command line.
 217  */
 218 static int mtdpart_setup_real(char *s)
 219 {
 220         cmdline_parsed = 1;
 221
 222         for( ; s != NULL; )
 223         {
 224                 struct cmdline_mtd_partition *this_mtd;
 225                 struct mtd_partition *parts;
 226                 int mtd_id_len;
 227                 int num_parts;
 228                 char *p, *mtd_id;
 229
 230                 mtd_id = s;
 231                 /* fetch <mtd-id> */
 232                 if (!(p = strchr(s, ':')))
 233                 {
 234                         printk(KERN_ERR ERRP "no mtd-id\n");
 235                         return 0;
 236                 }
 237                 mtd_id_len = p - mtd_id;
 238
 239                 dbg(("parsing <%s>\n", p+1));
 240
 241                 /*
 242                  * parse one mtd. have it reserve memory for the
 243                  * struct cmdline_mtd_partition and the mtd-id string.
 244                  */
 245                 parts = newpart(p + 1,          /* cmdline */
 246                                 &s,             /* out: updated cmdline ptr */
 247                                 &num_parts,     /* out: number of parts */
 248                                 0,              /* first partition */
 249                                 (unsigned char**)&this_mtd, /* out: extra mem */
 250                                 mtd_id_len + 1 + sizeof(*this_mtd) +
 251                                 sizeof(void*)-1 /*alignment*/);
 252                 if(!parts)
 253                 {
 254                         /*
 255                          * An error occurred. We're either:
 256                          * a) out of memory, or
 257                          * b) in the middle of the partition spec
 258                          * Either way, this mtd is hosed and we're
 259                          * unlikely to succeed in parsing any more
 260                          */
 261                          return 0;
 262                  }
 263
 264                 /* align this_mtd */
 265                 this_mtd = (struct cmdline_mtd_partition *)
 266                         ALIGN((unsigned long)this_mtd, sizeof(void*));
 267                 /* enter results */
 268                 this_mtd->parts = parts;
 269                 this_mtd->num_parts = num_parts;
 270                 this_mtd->mtd_id = (char*)(this_mtd + 1);
 271                 strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
 272
 273                 /* link into chain */
 274                 this_mtd->next = partitions;
 275                 partitions = this_mtd;
 276
 277                 dbg(("mtdid=<%s> num_parts=<%d>\n",
 278                      this_mtd->mtd_id, this_mtd->num_parts));
 279
 280
 281                 /* EOS - we're done */
 282                 if (*s == 0)
 283                         break;
 284
 285                 /* does another spec follow? */
 286                 if (*s != ';')
 287                 {
 288                         printk(KERN_ERR ERRP "bad character after partition (%c)\n", *s);
 289                         return 0;
 290                 }
 291                 s++;
 292         }
 293         return 1;
 294 }
 295
 296 /*
 297  * Main function to be called from the MTD mapping driver/device to
 298  * obtain the partitioning information. At this point the command line
 299  * arguments will actually be parsed and turned to struct mtd_partition
 300  * information. It returns partitions for the requested mtd device, or
 301  * the first one in the chain if a NULL mtd_id is passed in.
 302  */
 303 static int parse_cmdline_partitions(struct mtd_info *master,
 304                              struct mtd_partition **pparts,
 305                              unsigned long origin)
 306 {
 307         unsigned long offset;
 308         int i;
 309         struct cmdline_mtd_partition *part;
 310         const char *mtd_id = master->name;
 311
 312         /* parse command line */
 313         if (!cmdline_parsed)
 314                 mtdpart_setup_real(cmdline);
 315
 316         for(part = partitions; part; part = part->next)
 317         {
 318                 if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
 319                 {
 320                         for(i = 0, offset = 0; i < part->num_parts; i++)
 321                         {
 322                                 if (part->parts[i].offset == OFFSET_CONTINUOUS)
 323                                   part->parts[i].offset = offset;
 324                                 else
 325                                   offset = part->parts[i].offset;
 326                                 if (part->parts[i].size == SIZE_REMAINING)
 327                                   part->parts[i].size = master->size - offset;
 328                                 if (offset + part->parts[i].size > master->size)
 329                                 {
 330                                         printk(KERN_WARNING ERRP
 331                                                "%s: partitioning exceeds flash size, truncating\n",
 332                                                part->mtd_id);
 333                                         part->parts[i].size = master->size - offset;
 334                                         part->num_parts = i;
 335                                 }
 336                                 offset += part->parts[i].size;
 337                         }
 338                         *pparts = kmemdup(part->parts,
 339                                         sizeof(*part->parts) * part->num_parts,
 340                                         GFP_KERNEL);
 341                         if (!*pparts)
 342                                 return -ENOMEM;
 343                         return part->num_parts;
 344                 }
 345         }
 346         return 0;
 347 }
 348
 349
 350 /*
 351  * This is the handler for our kernel parameter, called from
 352  * main.c::checksetup(). Note that we can not yet kmalloc() anything,
 353  * so we only save the commandline for later processing.
 354  *
 355  * This function needs to be visible for bootloaders.
 356  */
 357 static int mtdpart_setup(char *s)
 358 {
 359         cmdline = s;
 360         return 1;
 361 }
 362
 363 __setup("mtdparts=", mtdpart_setup);
 364
 365 static struct mtd_part_parser cmdline_parser = {
 366         .owner = THIS_MODULE,
 367         .parse_fn = parse_cmdline_partitions,
 368         .name = "cmdlinepart",
 369 };
 370
 371 static int __init cmdline_parser_init(void)
 372 {
 373         return register_mtd_parser(&cmdline_parser);
 374 }
 375
 376 module_init(cmdline_parser_init);
 377
 378 MODULE_LICENSE("GPL");
 379 MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
 380 MODULE_DESCRIPTION("Command line configuration of MTD partitions");