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 * <partdef> := <size>[@<offset>][<name>][ro][lk]
  26 * <mtd-id>  := unique name used in mapping driver/device (mtd->name)
  27 * <size>    := standard linux memsize OR "-" to denote all remaining space
  28 *              size is automatically truncated at end of device
  29 *              if specified or trucated size is 0 the part is skipped
  30 * <offset>  := standard linux memsize
  31 *              if omitted the part will immediately follow the previous part
  32 *              or 0 if the first part
  33 * <name>    := '(' NAME ')'
  34 *              NAME will appear in /proc/mtd
  35 *
  36 * <size> and <offset> can be specified such that the parts are out of order
  37 * in physical memory and may even overlap.
  38 *
  39 * The parts are assigned MTD numbers in the order they are specified in the
  40 * command line regardless of their order in physical memory.
  41 *
  42 * Examples:
  43 *
  44 * 1 NOR Flash, with 1 single writable partition:
  45 * edb7312-nor:-
  46 *
  47 * 1 NOR Flash with 2 partitions, 1 NAND with one
  48 * edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
  49 */
  50
  51#include <linux/kernel.h>
  52#include <linux/slab.h>
  53#include <linux/mtd/mtd.h>
  54#include <linux/mtd/partitions.h>
  55#include <linux/module.h>
  56#include <linux/err.h>
  57
  58/* error message prefix */
  59#define ERRP "mtd: "
  60
  61/* debug macro */
  62#if 0
  63#define dbg(x) do { printk("DEBUG-CMDLINE-PART: "); printk x; } while(0)
  64#else
  65#define dbg(x)
  66#endif
  67
  68
  69/* special size referring to all the remaining space in a partition */
  70#define SIZE_REMAINING ULLONG_MAX
  71#define OFFSET_CONTINUOUS ULLONG_MAX
  72
  73struct cmdline_mtd_partition {
  74        struct cmdline_mtd_partition *next;
  75        char *mtd_id;
  76        int num_parts;
  77        struct mtd_partition *parts;
  78};
  79
  80/* mtdpart_setup() parses into here */
  81static struct cmdline_mtd_partition *partitions;
  82
  83/* the command line passed to mtdpart_setup() */
  84static char *mtdparts;
  85static char *cmdline;
  86static int cmdline_parsed;
  87
  88/*
  89 * Parse one partition definition for an MTD. Since there can be many
  90 * comma separated partition definitions, this function calls itself
  91 * recursively until no more partition definitions are found. Nice side
  92 * effect: the memory to keep the mtd_partition structs and the names
  93 * is allocated upon the last definition being found. At that point the
  94 * syntax has been verified ok.
  95 */
  96static struct mtd_partition * newpart(char *s,
  97                                      char **retptr,
  98                                      int *num_parts,
  99                                      int this_part,
 100                                      unsigned char **extra_mem_ptr,
 101                                      int extra_mem_size)
 102{
 103        struct mtd_partition *parts;
 104        unsigned long long size, offset = OFFSET_CONTINUOUS;
 105        char *name;
 106        int name_len;
 107        unsigned char *extra_mem;
 108        char delim;
 109        unsigned int mask_flags;
 110
 111        /* fetch the partition size */
 112        if (*s == '-') {
 113                /* assign all remaining space to this partition */
 114                size = SIZE_REMAINING;
 115                s++;
 116        } else {
 117                size = memparse(s, &s);
 118                if (size < PAGE_SIZE) {
 119                        printk(KERN_ERR ERRP "partition size too small (%llx)\n",
 120                               size);
 121                        return ERR_PTR(-EINVAL);
 122                }
 123        }
 124
 125        /* fetch partition name and flags */
 126        mask_flags = 0; /* this is going to be a regular partition */
 127        delim = 0;
 128
 129        /* check for offset */
 130        if (*s == '@') {
 131                s++;
 132                offset = memparse(s, &s);
 133        }
 134
 135        /* now look for name */
 136        if (*s == '(')
 137                delim = ')';
 138
 139        if (delim) {
 140                char *p;
 141
 142                name = ++s;
 143                p = strchr(name, delim);
 144                if (!p) {
 145                        printk(KERN_ERR ERRP "no closing %c found in partition name\n", delim);
 146                        return ERR_PTR(-EINVAL);
 147                }
 148                name_len = p - name;
 149                s = p + 1;
 150        } else {
 151                name = NULL;
 152                name_len = 13; /* Partition_000 */
 153        }
 154
 155        /* record name length for memory allocation later */
 156        extra_mem_size += name_len + 1;
 157
 158        /* test for options */
 159        if (strncmp(s, "ro", 2) == 0) {
 160                mask_flags |= MTD_WRITEABLE;
 161                s += 2;
 162        }
 163
 164        /* if lk is found do NOT unlock the MTD partition*/
 165        if (strncmp(s, "lk", 2) == 0) {
 166                mask_flags |= MTD_POWERUP_LOCK;
 167                s += 2;
 168        }
 169
 170        /* test if more partitions are following */
 171        if (*s == ',') {
 172                if (size == SIZE_REMAINING) {
 173                        printk(KERN_ERR ERRP "no partitions allowed after a fill-up partition\n");
 174                        return ERR_PTR(-EINVAL);
 175                }
 176                /* more partitions follow, parse them */
 177                parts = newpart(s + 1, &s, num_parts, this_part + 1,
 178                                &extra_mem, extra_mem_size);
 179                if (IS_ERR(parts))
 180                        return parts;
 181        } else {
 182                /* this is the last partition: allocate space for all */
 183                int alloc_size;
 184
 185                *num_parts = this_part + 1;
 186                alloc_size = *num_parts * sizeof(struct mtd_partition) +
 187                             extra_mem_size;
 188
 189                parts = kzalloc(alloc_size, GFP_KERNEL);
 190                if (!parts)
 191                        return ERR_PTR(-ENOMEM);
 192                extra_mem = (unsigned char *)(parts + *num_parts);
 193        }
 194
 195        /* enter this partition (offset will be calculated later if it is zero at this point) */
 196        parts[this_part].size = size;
 197        parts[this_part].offset = offset;
 198        parts[this_part].mask_flags = mask_flags;
 199        if (name)
 200                strlcpy(extra_mem, name, name_len + 1);
 201        else
 202                sprintf(extra_mem, "Partition_%03d", this_part);
 203        parts[this_part].name = extra_mem;
 204        extra_mem += name_len + 1;
 205
 206        dbg(("partition %d: name <%s>, offset %llx, size %llx, mask flags %x\n",
 207             this_part, parts[this_part].name, parts[this_part].offset,
 208             parts[this_part].size, parts[this_part].mask_flags));
 209
 210        /* return (updated) pointer to extra_mem memory */
 211        if (extra_mem_ptr)
 212                *extra_mem_ptr = extra_mem;
 213
 214        /* return (updated) pointer command line string */
 215        *retptr = s;
 216
 217        /* return partition table */
 218        return parts;
 219}
 220
 221/*
 222 * Parse the command line.
 223 */
 224static int mtdpart_setup_real(char *s)
 225{
 226        cmdline_parsed = 1;
 227
 228        for( ; s != NULL; )
 229        {
 230                struct cmdline_mtd_partition *this_mtd;
 231                struct mtd_partition *parts;
 232                int mtd_id_len, num_parts;
 233                char *p, *mtd_id;
 234
 235                mtd_id = s;
 236
 237                /* fetch <mtd-id> */
 238                p = strchr(s, ':');
 239                if (!p) {
 240                        printk(KERN_ERR ERRP "no mtd-id\n");
 241                        return -EINVAL;
 242                }
 243                mtd_id_len = p - mtd_id;
 244
 245                dbg(("parsing <%s>\n", p+1));
 246
 247                /*
 248                 * parse one mtd. have it reserve memory for the
 249                 * struct cmdline_mtd_partition and the mtd-id string.
 250                 */
 251                parts = newpart(p + 1,          /* cmdline */
 252                                &s,             /* out: updated cmdline ptr */
 253                                &num_parts,     /* out: number of parts */
 254                                0,              /* first partition */
 255                                (unsigned char**)&this_mtd, /* out: extra mem */
 256                                mtd_id_len + 1 + sizeof(*this_mtd) +
 257                                sizeof(void*)-1 /*alignment*/);
 258                if (IS_ERR(parts)) {
 259                        /*
 260                         * An error occurred. We're either:
 261                         * a) out of memory, or
 262                         * b) in the middle of the partition spec
 263                         * Either way, this mtd is hosed and we're
 264                         * unlikely to succeed in parsing any more
 265                         */
 266                         return PTR_ERR(parts);
 267                 }
 268
 269                /* align this_mtd */
 270                this_mtd = (struct cmdline_mtd_partition *)
 271                                ALIGN((unsigned long)this_mtd, sizeof(void *));
 272                /* enter results */
 273                this_mtd->parts = parts;
 274                this_mtd->num_parts = num_parts;
 275                this_mtd->mtd_id = (char*)(this_mtd + 1);
 276                strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
 277
 278                /* link into chain */
 279                this_mtd->next = partitions;
 280                partitions = this_mtd;
 281
 282                dbg(("mtdid=<%s> num_parts=<%d>\n",
 283                     this_mtd->mtd_id, this_mtd->num_parts));
 284
 285
 286                /* EOS - we're done */
 287                if (*s == 0)
 288                        break;
 289
 290                /* does another spec follow? */
 291                if (*s != ';') {
 292                        printk(KERN_ERR ERRP "bad character after partition (%c)\n", *s);
 293                        return -EINVAL;
 294                }
 295                s++;
 296        }
 297
 298        return 0;
 299}
 300
 301/*
 302 * Main function to be called from the MTD mapping driver/device to
 303 * obtain the partitioning information. At this point the command line
 304 * arguments will actually be parsed and turned to struct mtd_partition
 305 * information. It returns partitions for the requested mtd device, or
 306 * the first one in the chain if a NULL mtd_id is passed in.
 307 */
 308static int parse_cmdline_partitions(struct mtd_info *master,
 309                                    struct mtd_partition **pparts,
 310                                    struct mtd_part_parser_data *data)
 311{
 312        unsigned long long offset;
 313        int i, err;
 314        struct cmdline_mtd_partition *part;
 315        const char *mtd_id = master->name;
 316
 317        /* parse command line */
 318        if (!cmdline_parsed) {
 319                err = mtdpart_setup_real(cmdline);
 320                if (err)
 321                        return err;
 322        }
 323
 324        /*
 325         * Search for the partition definition matching master->name.
 326         * If master->name is not set, stop at first partition definition.
 327         */
 328        for (part = partitions; part; part = part->next) {
 329                if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
 330                        break;
 331        }
 332
 333        if (!part)
 334                return 0;
 335
 336        for (i = 0, offset = 0; i < part->num_parts; i++) {
 337                if (part->parts[i].offset == OFFSET_CONTINUOUS)
 338                        part->parts[i].offset = offset;
 339                else
 340                        offset = part->parts[i].offset;
 341
 342                if (part->parts[i].size == SIZE_REMAINING)
 343                        part->parts[i].size = master->size - offset;
 344
 345                if (offset + part->parts[i].size > master->size) {
 346                        printk(KERN_WARNING ERRP
 347                               "%s: partitioning exceeds flash size, truncating\n",
 348                               part->mtd_id);
 349                        part->parts[i].size = master->size - offset;
 350                }
 351                offset += part->parts[i].size;
 352
 353                if (part->parts[i].size == 0) {
 354                        printk(KERN_WARNING ERRP
 355                               "%s: skipping zero sized partition\n",
 356                               part->mtd_id);
 357                        part->num_parts--;
 358                        memmove(&part->parts[i], &part->parts[i + 1],
 359                                sizeof(*part->parts) * (part->num_parts - i));
 360                        i--;
 361                }
 362        }
 363
 364        *pparts = kmemdup(part->parts, sizeof(*part->parts) * part->num_parts,
 365                          GFP_KERNEL);
 366        if (!*pparts)
 367                return -ENOMEM;
 368
 369        return part->num_parts;
 370}
 371
 372
 373/*
 374 * This is the handler for our kernel parameter, called from
 375 * main.c::checksetup(). Note that we can not yet kmalloc() anything,
 376 * so we only save the commandline for later processing.
 377 *
 378 * This function needs to be visible for bootloaders.
 379 */
 380static int __init mtdpart_setup(char *s)
 381{
 382        cmdline = s;
 383        return 1;
 384}
 385
 386__setup("mtdparts=", mtdpart_setup);
 387
 388static struct mtd_part_parser cmdline_parser = {
 389        .owner = THIS_MODULE,
 390        .parse_fn = parse_cmdline_partitions,
 391        .name = "cmdlinepart",
 392};
 393
 394static int __init cmdline_parser_init(void)
 395{
 396        if (mtdparts)
 397                mtdpart_setup(mtdparts);
 398        return register_mtd_parser(&cmdline_parser);
 399}
 400
 401static void __exit cmdline_parser_exit(void)
 402{
 403        deregister_mtd_parser(&cmdline_parser);
 404}
 405
 406module_init(cmdline_parser_init);
 407module_exit(cmdline_parser_exit);
 408
 409MODULE_PARM_DESC(mtdparts, "Partitioning specification");
 410module_param(mtdparts, charp, 0);
 411
 412MODULE_LICENSE("GPL");
 413MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
 414MODULE_DESCRIPTION("Command line configuration of MTD partitions");
 415
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