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  * <partdef> := <size>[@offset][<name>][ro][lk]
  11  * <mtd-id>  := unique name used in mapping driver/device (mtd->name)
  12  * <size>    := standard linux memsize OR "-" to denote all remaining space
  13  * <name>    := '(' NAME ')'
  14  *
  15  * Examples:
  16  *
  17  * 1 NOR Flash, with 1 single writable partition:
  18  * edb7312-nor:-
  19  *
  20  * 1 NOR Flash with 2 partitions, 1 NAND with one
  21  * edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
  22  */
  23
  24 #include <linux/kernel.h>
  25 #include <linux/slab.h>
  26
  27 #include <linux/mtd/mtd.h>
  28 #include <linux/mtd/partitions.h>
  29 #include <linux/bootmem.h>
  30
  31 /* error message prefix */
  32 #define ERRP "mtd: "
  33
  34 /* debug macro */
  35 #if 0
  36 #define dbg(x) do { printk("DEBUG-CMDLINE-PART: "); printk x; } while(0)
  37 #else
  38 #define dbg(x)
  39 #endif
  40
  41
  42 /* special size referring to all the remaining space in a partition */
  43 #define SIZE_REMAINING UINT_MAX
  44 #define OFFSET_CONTINUOUS UINT_MAX
  45
  46 struct cmdline_mtd_partition {
  47         struct cmdline_mtd_partition *next;
  48         char *mtd_id;
  49         int num_parts;
  50         struct mtd_partition *parts;
  51 };
  52
  53 /* mtdpart_setup() parses into here */
  54 static struct cmdline_mtd_partition *partitions;
  55
  56 /* the command line passed to mtdpart_setupd() */
  57 static char *cmdline;
  58 static int cmdline_parsed = 0;
  59
  60 /*
  61  * Parse one partition definition for an MTD. Since there can be many
  62  * comma separated partition definitions, this function calls itself
  63  * recursively until no more partition definitions are found. Nice side
  64  * effect: the memory to keep the mtd_partition structs and the names
  65  * is allocated upon the last definition being found. At that point the
  66  * syntax has been verified ok.
  67  */
  68 static struct mtd_partition * newpart(char *s,
  69                                       char **retptr,
  70                                       int *num_parts,
  71                                       int this_part,
  72                                       unsigned char **extra_mem_ptr,
  73                                       int extra_mem_size)
  74 {
  75         struct mtd_partition *parts;
  76         unsigned long size;
  77         unsigned long offset = OFFSET_CONTINUOUS;
  78         char *name;
  79         int name_len;
  80         unsigned char *extra_mem;
  81         char delim;
  82         unsigned int mask_flags;
  83
  84         /* fetch the partition size */
  85         if (*s == '-')
  86         {       /* assign all remaining space to this partition */
  87                 size = SIZE_REMAINING;
  88                 s++;
  89         }
  90         else
  91         {
  92                 size = memparse(s, &s);
  93                 if (size < PAGE_SIZE)
  94                 {
  95                         printk(KERN_ERR ERRP "partition size too small (%lx)\n", size);
  96                         return NULL;
  97                 }
  98         }
  99
 100         /* fetch partition name and flags */
 101         mask_flags = 0; /* this is going to be a regular partition */
 102         delim = 0;
 103         /* check for offset */
 104         if (*s == '@')
 105         {
 106                 s++;
 107                 offset = memparse(s, &s);
 108         }
 109         /* now look for name */
 110         if (*s == '(')
 111         {
 112                 delim = ')';
 113         }
 114
 115         if (delim)
 116         {
 117                 char *p;
 118
 119                 name = ++s;
 120                 p = strchr(name, delim);
 121                 if (!p)
 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         /* if lk is found do NOT unlock the MTD partition*/
 146         if (strncmp(s, "lk", 2) == 0)
 147         {
 148                 mask_flags |= MTD_POWERUP_LOCK;
 149                 s += 2;
 150         }
 151
 152         /* test if more partitions are following */
 153         if (*s == ',')
 154         {
 155                 if (size == SIZE_REMAINING)
 156                 {
 157                         printk(KERN_ERR ERRP "no partitions allowed after a fill-up partition\n");
 158                         return NULL;
 159                 }
 160                 /* more partitions follow, parse them */
 161                 parts = newpart(s + 1, &s, num_parts, this_part + 1,
 162                                 &extra_mem, extra_mem_size);
 163                 if (!parts)
 164                         return NULL;
 165         }
 166         else
 167         {       /* this is the last partition: allocate space for all */
 168                 int alloc_size;
 169
 170                 *num_parts = this_part + 1;
 171                 alloc_size = *num_parts * sizeof(struct mtd_partition) +
 172                              extra_mem_size;
 173                 parts = kzalloc(alloc_size, GFP_KERNEL);
 174                 if (!parts)
 175                 {
 176                         printk(KERN_ERR ERRP "out of memory\n");
 177                         return NULL;
 178                 }
 179                 extra_mem = (unsigned char *)(parts + *num_parts);
 180         }
 181         /* enter this partition (offset will be calculated later if it is zero at this point) */
 182         parts[this_part].size = size;
 183         parts[this_part].offset = offset;
 184         parts[this_part].mask_flags = mask_flags;
 185         if (name)
 186         {
 187                 strlcpy(extra_mem, name, name_len + 1);
 188         }
 189         else
 190         {
 191                 sprintf(extra_mem, "Partition_%03d", this_part);
 192         }
 193         parts[this_part].name = extra_mem;
 194         extra_mem += name_len + 1;
 195
 196         dbg(("partition %d: name <%s>, offset %x, size %x, mask flags %x\n",
 197              this_part,
 198              parts[this_part].name,
 199              parts[this_part].offset,
 200              parts[this_part].size,
 201              parts[this_part].mask_flags));
 202
 203         /* return (updated) pointer to extra_mem memory */
 204         if (extra_mem_ptr)
 205           *extra_mem_ptr = extra_mem;
 206
 207         /* return (updated) pointer command line string */
 208         *retptr = s;
 209
 210         /* return partition table */
 211         return parts;
 212 }
 213
 214 /*
 215  * Parse the command line.
 216  */
 217 static int mtdpart_setup_real(char *s)
 218 {
 219         cmdline_parsed = 1;
 220
 221         for( ; s != NULL; )
 222         {
 223                 struct cmdline_mtd_partition *this_mtd;
 224                 struct mtd_partition *parts;
 225                 int mtd_id_len;
 226                 int num_parts;
 227                 char *p, *mtd_id;
 228
 229                 mtd_id = s;
 230                 /* fetch <mtd-id> */
 231                 if (!(p = strchr(s, ':')))
 232                 {
 233                         printk(KERN_ERR ERRP "no mtd-id\n");
 234                         return 0;
 235                 }
 236                 mtd_id_len = p - mtd_id;
 237
 238                 dbg(("parsing <%s>\n", p+1));
 239
 240                 /*
 241                  * parse one mtd. have it reserve memory for the
 242                  * struct cmdline_mtd_partition and the mtd-id string.
 243                  */
 244                 parts = newpart(p + 1,          /* cmdline */
 245                                 &s,             /* out: updated cmdline ptr */
 246                                 &num_parts,     /* out: number of parts */
 247                                 0,              /* first partition */
 248                                 (unsigned char**)&this_mtd, /* out: extra mem */
 249                                 mtd_id_len + 1 + sizeof(*this_mtd) +
 250                                 sizeof(void*)-1 /*alignment*/);
 251                 if(!parts)
 252                 {
 253                         /*
 254                          * An error occurred. We're either:
 255                          * a) out of memory, or
 256                          * b) in the middle of the partition spec
 257                          * Either way, this mtd is hosed and we're
 258                          * unlikely to succeed in parsing any more
 259                          */
 260                          return 0;
 261                  }
 262
 263                 /* align this_mtd */
 264                 this_mtd = (struct cmdline_mtd_partition *)
 265                         ALIGN((unsigned long)this_mtd, sizeof(void*));
 266                 /* enter results */
 267                 this_mtd->parts = parts;
 268                 this_mtd->num_parts = num_parts;
 269                 this_mtd->mtd_id = (char*)(this_mtd + 1);
 270                 strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
 271
 272                 /* link into chain */
 273                 this_mtd->next = partitions;
 274                 partitions = this_mtd;
 275
 276                 dbg(("mtdid=<%s> num_parts=<%d>\n",
 277                      this_mtd->mtd_id, this_mtd->num_parts));
 278
 279
 280                 /* EOS - we're done */
 281                 if (*s == 0)
 282                         break;
 283
 284                 /* does another spec follow? */
 285                 if (*s != ';')
 286                 {
 287                         printk(KERN_ERR ERRP "bad character after partition (%c)\n", *s);
 288                         return 0;
 289                 }
 290                 s++;
 291         }
 292         return 1;
 293 }
 294
 295 /*
 296  * Main function to be called from the MTD mapping driver/device to
 297  * obtain the partitioning information. At this point the command line
 298  * arguments will actually be parsed and turned to struct mtd_partition
 299  * information. It returns partitions for the requested mtd device, or
 300  * the first one in the chain if a NULL mtd_id is passed in.
 301  */
 302 static int parse_cmdline_partitions(struct mtd_info *master,
 303                              struct mtd_partition **pparts,
 304                              unsigned long origin)
 305 {
 306         unsigned long offset;
 307         int i;
 308         struct cmdline_mtd_partition *part;
 309         const char *mtd_id = master->name;
 310
 311         /* parse command line */
 312         if (!cmdline_parsed)
 313                 mtdpart_setup_real(cmdline);
 314
 315         for(part = partitions; part; part = part->next)
 316         {
 317                 if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
 318                 {
 319                         for(i = 0, offset = 0; i < part->num_parts; i++)
 320                         {
 321                                 if (part->parts[i].offset == OFFSET_CONTINUOUS)
 322                                   part->parts[i].offset = offset;
 323                                 else
 324                                   offset = part->parts[i].offset;
 325                                 if (part->parts[i].size == SIZE_REMAINING)
 326                                   part->parts[i].size = master->size - offset;
 327                                 if (offset + part->parts[i].size > master->size)
 328                                 {
 329                                         printk(KERN_WARNING ERRP
 330                                                "%s: partitioning exceeds flash size, truncating\n",
 331                                                part->mtd_id);
 332                                         part->parts[i].size = master->size - offset;
 333                                         part->num_parts = i;
 334                                 }
 335                                 offset += part->parts[i].size;
 336                         }
 337                         *pparts = part->parts;
 338                         return part->num_parts;
 339                 }
 340         }
 341         return 0;
 342 }
 343
 344
 345 /*
 346  * This is the handler for our kernel parameter, called from
 347  * main.c::checksetup(). Note that we can not yet kmalloc() anything,
 348  * so we only save the commandline for later processing.
 349  *
 350  * This function needs to be visible for bootloaders.
 351  */
 352 static int mtdpart_setup(char *s)
 353 {
 354         cmdline = s;
 355         return 1;
 356 }
 357
 358 __setup("mtdparts=", mtdpart_setup);
 359
 360 static struct mtd_part_parser cmdline_parser = {
 361         .owner = THIS_MODULE,
 362         .parse_fn = parse_cmdline_partitions,
 363         .name = "cmdlinepart",
 364 };
 365
 366 static int __init cmdline_parser_init(void)
 367 {
 368         return register_mtd_parser(&cmdline_parser);
 369 }
 370
 371 module_init(cmdline_parser_init);
 372
 373 MODULE_LICENSE("GPL");
 374 MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
 375 MODULE_DESCRIPTION("Command line configuration of MTD partitions");