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 UINT_MAX
  60#define OFFSET_CONTINUOUS UINT_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 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 (%lx)\n", size);
 108                        return ERR_PTR(-EINVAL);
 109                }
 110        }
 111
 112        /* fetch partition name and flags */
 113        mask_flags = 0; /* this is going to be a regular partition */
 114        delim = 0;
 115
 116        /* check for offset */
 117        if (*s == '@') {
 118                s++;
 119                offset = memparse(s, &s);
 120        }
 121
 122        /* now look for name */
 123        if (*s == '(')
 124                delim = ')';
 125
 126        if (delim) {
 127                char *p;
 128
 129                name = ++s;
 130                p = strchr(name, delim);
 131                if (!p) {
 132                        printk(KERN_ERR ERRP "no closing %c found in partition name\n", delim);
 133                        return ERR_PTR(-EINVAL);
 134                }
 135                name_len = p - name;
 136                s = p + 1;
 137        } else {
 138                name = NULL;
 139                name_len = 13; /* Partition_000 */
 140        }
 141
 142        /* record name length for memory allocation later */
 143        extra_mem_size += name_len + 1;
 144
 145        /* test for options */
 146        if (strncmp(s, "ro", 2) == 0) {
 147                mask_flags |= MTD_WRITEABLE;
 148                s += 2;
 149        }
 150
 151        /* if lk is found do NOT unlock the MTD partition*/
 152        if (strncmp(s, "lk", 2) == 0) {
 153                mask_flags |= MTD_POWERUP_LOCK;
 154                s += 2;
 155        }
 156
 157        /* test if more partitions are following */
 158        if (*s == ',') {
 159                if (size == SIZE_REMAINING) {
 160                        printk(KERN_ERR ERRP "no partitions allowed after a fill-up partition\n");
 161                        return ERR_PTR(-EINVAL);
 162                }
 163                /* more partitions follow, parse them */
 164                parts = newpart(s + 1, &s, num_parts, this_part + 1,
 165                                &extra_mem, extra_mem_size);
 166                if (IS_ERR(parts))
 167                        return parts;
 168        } else {
 169                /* this is the last partition: allocate space for all */
 170                int alloc_size;
 171
 172                *num_parts = this_part + 1;
 173                alloc_size = *num_parts * sizeof(struct mtd_partition) +
 174                             extra_mem_size;
 175
 176                parts = kzalloc(alloc_size, GFP_KERNEL);
 177                if (!parts)
 178                        return ERR_PTR(-ENOMEM);
 179                extra_mem = (unsigned char *)(parts + *num_parts);
 180        }
 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                strlcpy(extra_mem, name, name_len + 1);
 188        else
 189                sprintf(extra_mem, "Partition_%03d", this_part);
 190        parts[this_part].name = extra_mem;
 191        extra_mem += name_len + 1;
 192
 193        dbg(("partition %d: name <%s>, offset %llx, size %llx, mask flags %x\n",
 194             this_part, parts[this_part].name, parts[this_part].offset,
 195             parts[this_part].size, parts[this_part].mask_flags));
 196
 197        /* return (updated) pointer to extra_mem memory */
 198        if (extra_mem_ptr)
 199                *extra_mem_ptr = extra_mem;
 200
 201        /* return (updated) pointer command line string */
 202        *retptr = s;
 203
 204        /* return partition table */
 205        return parts;
 206}
 207
 208/*
 209 * Parse the command line.
 210 */
 211static int mtdpart_setup_real(char *s)
 212{
 213        cmdline_parsed = 1;
 214
 215        for( ; s != NULL; )
 216        {
 217                struct cmdline_mtd_partition *this_mtd;
 218                struct mtd_partition *parts;
 219                int mtd_id_len, num_parts;
 220                char *p, *mtd_id;
 221
 222                mtd_id = s;
 223
 224                /* fetch <mtd-id> */
 225                p = strchr(s, ':');
 226                if (!p) {
 227                        printk(KERN_ERR ERRP "no mtd-id\n");
 228                        return -EINVAL;
 229                }
 230                mtd_id_len = p - mtd_id;
 231
 232                dbg(("parsing <%s>\n", p+1));
 233
 234                /*
 235                 * parse one mtd. have it reserve memory for the
 236                 * struct cmdline_mtd_partition and the mtd-id string.
 237                 */
 238                parts = newpart(p + 1,          /* cmdline */
 239                                &s,             /* out: updated cmdline ptr */
 240                                &num_parts,     /* out: number of parts */
 241                                0,              /* first partition */
 242                                (unsigned char**)&this_mtd, /* out: extra mem */
 243                                mtd_id_len + 1 + sizeof(*this_mtd) +
 244                                sizeof(void*)-1 /*alignment*/);
 245                if (IS_ERR(parts)) {
 246                        /*
 247                         * An error occurred. We're either:
 248                         * a) out of memory, or
 249                         * b) in the middle of the partition spec
 250                         * Either way, this mtd is hosed and we're
 251                         * unlikely to succeed in parsing any more
 252                         */
 253                         return PTR_ERR(parts);
 254                 }
 255
 256                /* align this_mtd */
 257                this_mtd = (struct cmdline_mtd_partition *)
 258                                ALIGN((unsigned long)this_mtd, sizeof(void *));
 259                /* enter results */
 260                this_mtd->parts = parts;
 261                this_mtd->num_parts = num_parts;
 262                this_mtd->mtd_id = (char*)(this_mtd + 1);
 263                strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
 264
 265                /* link into chain */
 266                this_mtd->next = partitions;
 267                partitions = this_mtd;
 268
 269                dbg(("mtdid=<%s> num_parts=<%d>\n",
 270                     this_mtd->mtd_id, this_mtd->num_parts));
 271
 272
 273                /* EOS - we're done */
 274                if (*s == 0)
 275                        break;
 276
 277                /* does another spec follow? */
 278                if (*s != ';') {
 279                        printk(KERN_ERR ERRP "bad character after partition (%c)\n", *s);
 280                        return -EINVAL;
 281                }
 282                s++;
 283        }
 284
 285        return 0;
 286}
 287
 288/*
 289 * Main function to be called from the MTD mapping driver/device to
 290 * obtain the partitioning information. At this point the command line
 291 * arguments will actually be parsed and turned to struct mtd_partition
 292 * information. It returns partitions for the requested mtd device, or
 293 * the first one in the chain if a NULL mtd_id is passed in.
 294 */
 295static int parse_cmdline_partitions(struct mtd_info *master,
 296                                    struct mtd_partition **pparts,
 297                                    struct mtd_part_parser_data *data)
 298{
 299        unsigned long offset;
 300        int i, err;
 301        struct cmdline_mtd_partition *part;
 302        const char *mtd_id = master->name;
 303
 304        /* parse command line */
 305        if (!cmdline_parsed) {
 306                err = mtdpart_setup_real(cmdline);
 307                if (err)
 308                        return err;
 309        }
 310
 311        for (part = partitions; part; part = part->next) {
 312                if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id))) {
 313                        for (i = 0, offset = 0; i < part->num_parts; i++) {
 314                                if (part->parts[i].offset == OFFSET_CONTINUOUS)
 315                                        part->parts[i].offset = offset;
 316                                else
 317                                        offset = part->parts[i].offset;
 318
 319                                if (part->parts[i].size == SIZE_REMAINING)
 320                                        part->parts[i].size = master->size - offset;
 321
 322                                if (part->parts[i].size == 0) {
 323                                        printk(KERN_WARNING ERRP
 324                                               "%s: skipping zero sized partition\n",
 325                                               part->mtd_id);
 326                                        part->num_parts--;
 327                                        memmove(&part->parts[i],
 328                                                &part->parts[i + 1],
 329                                                sizeof(*part->parts) * (part->num_parts - i));
 330                                        continue;
 331                                }
 332
 333                                if (offset + part->parts[i].size > master->size) {
 334                                        printk(KERN_WARNING ERRP
 335                                               "%s: partitioning exceeds flash size, truncating\n",
 336                                               part->mtd_id);
 337                                        part->parts[i].size = master->size - offset;
 338                                }
 339                                offset += part->parts[i].size;
 340                        }
 341
 342                        *pparts = kmemdup(part->parts,
 343                                        sizeof(*part->parts) * part->num_parts,
 344                                        GFP_KERNEL);
 345                        if (!*pparts)
 346                                return -ENOMEM;
 347
 348                        return part->num_parts;
 349                }
 350        }
 351
 352        return 0;
 353}
 354
 355
 356/*
 357 * This is the handler for our kernel parameter, called from
 358 * main.c::checksetup(). Note that we can not yet kmalloc() anything,
 359 * so we only save the commandline for later processing.
 360 *
 361 * This function needs to be visible for bootloaders.
 362 */
 363static int mtdpart_setup(char *s)
 364{
 365        cmdline = s;
 366        return 1;
 367}
 368
 369__setup("mtdparts=", mtdpart_setup);
 370
 371static struct mtd_part_parser cmdline_parser = {
 372        .owner = THIS_MODULE,
 373        .parse_fn = parse_cmdline_partitions,
 374        .name = "cmdlinepart",
 375};
 376
 377static int __init cmdline_parser_init(void)
 378{
 379        return register_mtd_parser(&cmdline_parser);
 380}
 381
 382module_init(cmdline_parser_init);
 383
 384MODULE_LICENSE("GPL");
 385MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
 386MODULE_DESCRIPTION("Command line configuration of MTD partitions");
 387
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