linux/drivers/mtd/cmdlinepart.c
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   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][lk]
  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
  48struct 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 */
  56static struct cmdline_mtd_partition *partitions;
  57
  58/* the command line passed to mtdpart_setupd() */
  59static char *cmdline;
  60static 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 */
  70static 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        /* 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                if ((parts = newpart(s + 1, &s, num_parts,
 163                                     this_part + 1, &extra_mem, extra_mem_size)) == 0)
 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 */
 217static 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 */
 302static 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        char *mtd_id = master->name;
 310
 311        if(!cmdline)
 312                return -EINVAL;
 313
 314        /* parse command line */
 315        if (!cmdline_parsed)
 316                mtdpart_setup_real(cmdline);
 317
 318        for(part = partitions; part; part = part->next)
 319        {
 320                if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
 321                {
 322                        for(i = 0, offset = 0; i < part->num_parts; i++)
 323                        {
 324                                if (part->parts[i].offset == OFFSET_CONTINUOUS)
 325                                  part->parts[i].offset = offset;
 326                                else
 327                                  offset = part->parts[i].offset;
 328                                if (part->parts[i].size == SIZE_REMAINING)
 329                                  part->parts[i].size = master->size - offset;
 330                                if (offset + part->parts[i].size > master->size)
 331                                {
 332                                        printk(KERN_WARNING ERRP
 333                                               "%s: partitioning exceeds flash size, truncating\n",
 334                                               part->mtd_id);
 335                                        part->parts[i].size = master->size - offset;
 336                                        part->num_parts = i;
 337                                }
 338                                offset += part->parts[i].size;
 339                        }
 340                        *pparts = part->parts;
 341                        return part->num_parts;
 342                }
 343        }
 344        return -EINVAL;
 345}
 346
 347
 348/*
 349 * This is the handler for our kernel parameter, called from
 350 * main.c::checksetup(). Note that we can not yet kmalloc() anything,
 351 * so we only save the commandline for later processing.
 352 *
 353 * This function needs to be visible for bootloaders.
 354 */
 355static int mtdpart_setup(char *s)
 356{
 357        cmdline = s;
 358        return 1;
 359}
 360
 361__setup("mtdparts=", mtdpart_setup);
 362
 363static struct mtd_part_parser cmdline_parser = {
 364        .owner = THIS_MODULE,
 365        .parse_fn = parse_cmdline_partitions,
 366        .name = "cmdlinepart",
 367};
 368
 369static int __init cmdline_parser_init(void)
 370{
 371        return register_mtd_parser(&cmdline_parser);
 372}
 373
 374module_init(cmdline_parser_init);
 375
 376MODULE_LICENSE("GPL");
 377MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
 378MODULE_DESCRIPTION("Command line configuration of MTD partitions");
 379
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