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 * Copyright © 2002-2010 David Woodhouse <dwmw2@infradead.org>
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License as published by
   9 * the Free Software Foundation; either version 2 of the License, or
  10 * (at your option) any later version.
  11 *
  12 * This program is distributed in the hope that it will be useful,
  13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 * GNU General Public License for more details.
  16 *
  17 * You should have received a copy of the GNU General Public License
  18 * along with this program; if not, write to the Free Software
  19 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  20 *
  21 * The format for the command line is as follows:
  22 *
  23 * mtdparts=<mtddef>[;<mtddef]
  24 * <mtddef>  := <mtd-id>:<partdef>[,<partdef>]
  25 *              where <mtd-id> is the name from the "cat /proc/mtd" command
  26 * <partdef> := <size>[@offset][<name>][ro][lk]
  27 * <mtd-id>  := unique name used in mapping driver/device (mtd->name)
  28 * <size>    := standard linux memsize OR "-" to denote all remaining space
  29 * <name>    := '(' NAME ')'
  30 *
  31 * Examples:
  32 *
  33 * 1 NOR Flash, with 1 single writable partition:
  34 * edb7312-nor:-
  35 *
  36 * 1 NOR Flash with 2 partitions, 1 NAND with one
  37 * edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
  38 */
  39
  40#include <linux/kernel.h>
  41#include <linux/slab.h>
  42#include <linux/mtd/mtd.h>
  43#include <linux/mtd/partitions.h>
  44#include <linux/module.h>
  45#include <linux/err.h>
  46
  47/* error message prefix */
  48#define ERRP "mtd: "
  49
  50/* debug macro */
  51#if 0
  52#define dbg(x) do { printk("DEBUG-CMDLINE-PART: "); printk x; } while(0)
  53#else
  54#define dbg(x)
  55#endif
  56
  57
  58/* special size referring to all the remaining space in a partition */
  59#define SIZE_REMAINING ULLONG_MAX
  60#define OFFSET_CONTINUOUS ULLONG_MAX
  61
  62struct cmdline_mtd_partition {
  63        struct cmdline_mtd_partition *next;
  64        char *mtd_id;
  65        int num_parts;
  66        struct mtd_partition *parts;
  67};
  68
  69/* mtdpart_setup() parses into here */
  70static struct cmdline_mtd_partition *partitions;
  71
  72/* the command line passed to mtdpart_setup() */
  73static char *cmdline;
  74static int cmdline_parsed;
  75
  76/*
  77 * Parse one partition definition for an MTD. Since there can be many
  78 * comma separated partition definitions, this function calls itself
  79 * recursively until no more partition definitions are found. Nice side
  80 * effect: the memory to keep the mtd_partition structs and the names
  81 * is allocated upon the last definition being found. At that point the
  82 * syntax has been verified ok.
  83 */
  84static struct mtd_partition * newpart(char *s,
  85                                      char **retptr,
  86                                      int *num_parts,
  87                                      int this_part,
  88                                      unsigned char **extra_mem_ptr,
  89                                      int extra_mem_size)
  90{
  91        struct mtd_partition *parts;
  92        unsigned long long size, offset = OFFSET_CONTINUOUS;
  93        char *name;
  94        int name_len;
  95        unsigned char *extra_mem;
  96        char delim;
  97        unsigned int mask_flags;
  98
  99        /* fetch the partition size */
 100        if (*s == '-') {
 101                /* assign all remaining space to this partition */
 102                size = SIZE_REMAINING;
 103                s++;
 104        } else {
 105                size = memparse(s, &s);
 106                if (size < PAGE_SIZE) {
 107                        printk(KERN_ERR ERRP "partition size too small (%llx)\n",
 108                               size);
 109                        return ERR_PTR(-EINVAL);
 110                }
 111        }
 112
 113        /* fetch partition name and flags */
 114        mask_flags = 0; /* this is going to be a regular partition */
 115        delim = 0;
 116
 117        /* check for offset */
 118        if (*s == '@') {
 119                s++;
 120                offset = memparse(s, &s);
 121        }
 122
 123        /* now look for name */
 124        if (*s == '(')
 125                delim = ')';
 126
 127        if (delim) {
 128                char *p;
 129
 130                name = ++s;
 131                p = strchr(name, delim);
 132                if (!p) {
 133                        printk(KERN_ERR ERRP "no closing %c found in partition name\n", delim);
 134                        return ERR_PTR(-EINVAL);
 135                }
 136                name_len = p - name;
 137                s = p + 1;
 138        } else {
 139                name = NULL;
 140                name_len = 13; /* Partition_000 */
 141        }
 142
 143        /* record name length for memory allocation later */
 144        extra_mem_size += name_len + 1;
 145
 146        /* test for options */
 147        if (strncmp(s, "ro", 2) == 0) {
 148                mask_flags |= MTD_WRITEABLE;
 149                s += 2;
 150        }
 151
 152        /* if lk is found do NOT unlock the MTD partition*/
 153        if (strncmp(s, "lk", 2) == 0) {
 154                mask_flags |= MTD_POWERUP_LOCK;
 155                s += 2;
 156        }
 157
 158        /* test if more partitions are following */
 159        if (*s == ',') {
 160                if (size == SIZE_REMAINING) {
 161                        printk(KERN_ERR ERRP "no partitions allowed after a fill-up partition\n");
 162                        return ERR_PTR(-EINVAL);
 163                }
 164                /* more partitions follow, parse them */
 165                parts = newpart(s + 1, &s, num_parts, this_part + 1,
 166                                &extra_mem, extra_mem_size);
 167                if (IS_ERR(parts))
 168                        return parts;
 169        } else {
 170                /* this is the last partition: allocate space for all */
 171                int alloc_size;
 172
 173                *num_parts = this_part + 1;
 174                alloc_size = *num_parts * sizeof(struct mtd_partition) +
 175                             extra_mem_size;
 176
 177                parts = kzalloc(alloc_size, GFP_KERNEL);
 178                if (!parts)
 179                        return ERR_PTR(-ENOMEM);
 180                extra_mem = (unsigned char *)(parts + *num_parts);
 181        }
 182
 183        /* enter this partition (offset will be calculated later if it is zero at this point) */
 184        parts[this_part].size = size;
 185        parts[this_part].offset = offset;
 186        parts[this_part].mask_flags = mask_flags;
 187        if (name)
 188                strlcpy(extra_mem, name, name_len + 1);
 189        else
 190                sprintf(extra_mem, "Partition_%03d", this_part);
 191        parts[this_part].name = extra_mem;
 192        extra_mem += name_len + 1;
 193
 194        dbg(("partition %d: name <%s>, offset %llx, size %llx, mask flags %x\n",
 195             this_part, parts[this_part].name, parts[this_part].offset,
 196             parts[this_part].size, parts[this_part].mask_flags));
 197
 198        /* return (updated) pointer to extra_mem memory */
 199        if (extra_mem_ptr)
 200                *extra_mem_ptr = extra_mem;
 201
 202        /* return (updated) pointer command line string */
 203        *retptr = s;
 204
 205        /* return partition table */
 206        return parts;
 207}
 208
 209/*
 210 * Parse the command line.
 211 */
 212static int mtdpart_setup_real(char *s)
 213{
 214        cmdline_parsed = 1;
 215
 216        for( ; s != NULL; )
 217        {
 218                struct cmdline_mtd_partition *this_mtd;
 219                struct mtd_partition *parts;
 220                int mtd_id_len, num_parts;
 221                char *p, *mtd_id;
 222
 223                mtd_id = s;
 224
 225                /* fetch <mtd-id> */
 226                p = strchr(s, ':');
 227                if (!p) {
 228                        printk(KERN_ERR ERRP "no mtd-id\n");
 229                        return -EINVAL;
 230                }
 231                mtd_id_len = p - mtd_id;
 232
 233                dbg(("parsing <%s>\n", p+1));
 234
 235                /*
 236                 * parse one mtd. have it reserve memory for the
 237                 * struct cmdline_mtd_partition and the mtd-id string.
 238                 */
 239                parts = newpart(p + 1,          /* cmdline */
 240                                &s,             /* out: updated cmdline ptr */
 241                                &num_parts,     /* out: number of parts */
 242                                0,              /* first partition */
 243                                (unsigned char**)&this_mtd, /* out: extra mem */
 244                                mtd_id_len + 1 + sizeof(*this_mtd) +
 245                                sizeof(void*)-1 /*alignment*/);
 246                if (IS_ERR(parts)) {
 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 PTR_ERR(parts);
 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                        printk(KERN_ERR ERRP "bad character after partition (%c)\n", *s);
 281                        return -EINVAL;
 282                }
 283                s++;
 284        }
 285
 286        return 0;
 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 */
 296static int parse_cmdline_partitions(struct mtd_info *master,
 297                                    struct mtd_partition **pparts,
 298                                    struct mtd_part_parser_data *data)
 299{
 300        unsigned long long offset;
 301        int i, err;
 302        struct cmdline_mtd_partition *part;
 303        const char *mtd_id = master->name;
 304
 305        /* parse command line */
 306        if (!cmdline_parsed) {
 307                err = mtdpart_setup_real(cmdline);
 308                if (err)
 309                        return err;
 310        }
 311
 312        /*
 313         * Search for the partition definition matching master->name.
 314         * If master->name is not set, stop at first partition definition.
 315         */
 316        for (part = partitions; part; part = part->next) {
 317                if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
 318                        break;
 319        }
 320
 321        if (!part)
 322                return 0;
 323
 324        for (i = 0, offset = 0; i < part->num_parts; i++) {
 325                if (part->parts[i].offset == OFFSET_CONTINUOUS)
 326                        part->parts[i].offset = offset;
 327                else
 328                        offset = part->parts[i].offset;
 329
 330                if (part->parts[i].size == SIZE_REMAINING)
 331                        part->parts[i].size = master->size - offset;
 332
 333                if (part->parts[i].size == 0) {
 334                        printk(KERN_WARNING ERRP
 335                               "%s: skipping zero sized partition\n",
 336                               part->mtd_id);
 337                        part->num_parts--;
 338                        memmove(&part->parts[i], &part->parts[i + 1],
 339                                sizeof(*part->parts) * (part->num_parts - i));
 340                        continue;
 341                }
 342
 343                if (offset + part->parts[i].size > master->size) {
 344                        printk(KERN_WARNING ERRP
 345                               "%s: partitioning exceeds flash size, truncating\n",
 346                               part->mtd_id);
 347                        part->parts[i].size = master->size - offset;
 348                }
 349                offset += part->parts[i].size;
 350        }
 351
 352        *pparts = kmemdup(part->parts, sizeof(*part->parts) * part->num_parts,
 353                          GFP_KERNEL);
 354        if (!*pparts)
 355                return -ENOMEM;
 356
 357        return part->num_parts;
 358}
 359
 360
 361/*
 362 * This is the handler for our kernel parameter, called from
 363 * main.c::checksetup(). Note that we can not yet kmalloc() anything,
 364 * so we only save the commandline for later processing.
 365 *
 366 * This function needs to be visible for bootloaders.
 367 */
 368static int mtdpart_setup(char *s)
 369{
 370        cmdline = s;
 371        return 1;
 372}
 373
 374__setup("mtdparts=", mtdpart_setup);
 375
 376static struct mtd_part_parser cmdline_parser = {
 377        .owner = THIS_MODULE,
 378        .parse_fn = parse_cmdline_partitions,
 379        .name = "cmdlinepart",
 380};
 381
 382static int __init cmdline_parser_init(void)
 383{
 384        return register_mtd_parser(&cmdline_parser);
 385}
 386
 387module_init(cmdline_parser_init);
 388
 389MODULE_LICENSE("GPL");
 390MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
 391MODULE_DESCRIPTION("Command line configuration of MTD partitions");
 392
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