linux/drivers/mtd/cmdlinepart.c
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   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
  47struct 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 */
  55static struct cmdline_mtd_partition *partitions;
  56
  57/* the command line passed to mtdpart_setupd() */
  58static char *cmdline;
  59static 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 */
  69static 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 */
 218static 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 */
 303static 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 = part->parts;
 339                        return part->num_parts;
 340                }
 341        }
 342        return 0;
 343}
 344
 345
 346/*
 347 * This is the handler for our kernel parameter, called from
 348 * main.c::checksetup(). Note that we can not yet kmalloc() anything,
 349 * so we only save the commandline for later processing.
 350 *
 351 * This function needs to be visible for bootloaders.
 352 */
 353static int mtdpart_setup(char *s)
 354{
 355        cmdline = s;
 356        return 1;
 357}
 358
 359__setup("mtdparts=", mtdpart_setup);
 360
 361static struct mtd_part_parser cmdline_parser = {
 362        .owner = THIS_MODULE,
 363        .parse_fn = parse_cmdline_partitions,
 364        .name = "cmdlinepart",
 365};
 366
 367static int __init cmdline_parser_init(void)
 368{
 369        return register_mtd_parser(&cmdline_parser);
 370}
 371
 372module_init(cmdline_parser_init);
 373
 374MODULE_LICENSE("GPL");
 375MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
 376MODULE_DESCRIPTION("Command line configuration of MTD partitions");
 377