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