linux/drivers/mtd/parsers/cmdlinepart.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Read flash partition table from command line
   4 *
   5 * Copyright \xC2\xA9 2002      SYSGO Real-Time Solutions GmbH
   6 * Copyright \xC2\xA9 2002-2010 David Woodhouse <dwmw2@infradead.org>
   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][slc]
  13 * <mtd-id>  := unique name used in mapping driver/device (mtd->name)
  14 * <size>    := standard linux memsize OR "-" to denote all remaining space
  15 *              size is automatically truncated at end of device
  16 *              if specified or truncated size is 0 the part is skipped
  17 * <offset>  := standard linux memsize
  18 *              if omitted the part will immediately follow the previous part
  19 *              or 0 if the first part
  20 * <name>    := '(' NAME ')'
  21 *              NAME will appear in /proc/mtd
  22 *
  23 * <size> and <offset> can be specified such that the parts are out of order
  24 * in physical memory and may even overlap.
  25 *
  26 * The parts are assigned MTD numbers in the order they are specified in the
  27 * command line regardless of their order in physical memory.
  28 *
  29 * Examples:
  30 *
  31 * 1 NOR Flash, with 1 single writable partition:
  32 * edb7312-nor:-
  33 *
  34 * 1 NOR Flash with 2 partitions, 1 NAND with one
  35 * edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
  36 */
  37
  38#define pr_fmt(fmt)     "mtd: " fmt
  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/* debug macro */
  48#if 0
  49#define dbg(x) do { printk("DEBUG-CMDLINE-PART: "); printk x; } while(0)
  50#else
  51#define dbg(x)
  52#endif
  53
  54
  55/* special size referring to all the remaining space in a partition */
  56#define SIZE_REMAINING ULLONG_MAX
  57#define OFFSET_CONTINUOUS ULLONG_MAX
  58
  59struct cmdline_mtd_partition {
  60        struct cmdline_mtd_partition *next;
  61        char *mtd_id;
  62        int num_parts;
  63        struct mtd_partition *parts;
  64};
  65
  66/* mtdpart_setup() parses into here */
  67static struct cmdline_mtd_partition *partitions;
  68
  69/* the command line passed to mtdpart_setup() */
  70static char *mtdparts;
  71static char *cmdline;
  72static int cmdline_parsed;
  73
  74/*
  75 * Parse one partition definition for an MTD. Since there can be many
  76 * comma separated partition definitions, this function calls itself
  77 * recursively until no more partition definitions are found. Nice side
  78 * effect: the memory to keep the mtd_partition structs and the names
  79 * is allocated upon the last definition being found. At that point the
  80 * syntax has been verified ok.
  81 */
  82static struct mtd_partition * newpart(char *s,
  83                                      char **retptr,
  84                                      int *num_parts,
  85                                      int this_part,
  86                                      unsigned char **extra_mem_ptr,
  87                                      int extra_mem_size)
  88{
  89        struct mtd_partition *parts;
  90        unsigned long long size, offset = OFFSET_CONTINUOUS;
  91        char *name;
  92        int name_len;
  93        unsigned char *extra_mem;
  94        char delim;
  95        unsigned int mask_flags, add_flags;
  96
  97        /* fetch the partition size */
  98        if (*s == '-') {
  99                /* assign all remaining space to this partition */
 100                size = SIZE_REMAINING;
 101                s++;
 102        } else {
 103                size = memparse(s, &s);
 104                if (!size) {
 105                        pr_err("partition has size 0\n");
 106                        return ERR_PTR(-EINVAL);
 107                }
 108        }
 109
 110        /* fetch partition name and flags */
 111        mask_flags = 0; /* this is going to be a regular partition */
 112        add_flags = 0;
 113        delim = 0;
 114
 115        /* check for offset */
 116        if (*s == '@') {
 117                s++;
 118                offset = memparse(s, &s);
 119        }
 120
 121        /* now look for name */
 122        if (*s == '(')
 123                delim = ')';
 124
 125        if (delim) {
 126                char *p;
 127
 128                name = ++s;
 129                p = strchr(name, delim);
 130                if (!p) {
 131                        pr_err("no closing %c found in partition name\n", delim);
 132                        return ERR_PTR(-EINVAL);
 133                }
 134                name_len = p - name;
 135                s = p + 1;
 136        } else {
 137                name = NULL;
 138                name_len = 13; /* Partition_000 */
 139        }
 140
 141        /* record name length for memory allocation later */
 142        extra_mem_size += name_len + 1;
 143
 144        /* test for options */
 145        if (strncmp(s, "ro", 2) == 0) {
 146                mask_flags |= MTD_WRITEABLE;
 147                s += 2;
 148        }
 149
 150        /* if lk is found do NOT unlock the MTD partition*/
 151        if (strncmp(s, "lk", 2) == 0) {
 152                mask_flags |= MTD_POWERUP_LOCK;
 153                s += 2;
 154        }
 155
 156        /* if slc is found use emulated SLC mode on this partition*/
 157        if (!strncmp(s, "slc", 3)) {
 158                add_flags |= MTD_SLC_ON_MLC_EMULATION;
 159                s += 3;
 160        }
 161
 162        /* test if more partitions are following */
 163        if (*s == ',') {
 164                if (size == SIZE_REMAINING) {
 165                        pr_err("no partitions allowed after a fill-up partition\n");
 166                        return ERR_PTR(-EINVAL);
 167                }
 168                /* more partitions follow, parse them */
 169                parts = newpart(s + 1, &s, num_parts, this_part + 1,
 170                                &extra_mem, extra_mem_size);
 171                if (IS_ERR(parts))
 172                        return parts;
 173        } else {
 174                /* this is the last partition: allocate space for all */
 175                int alloc_size;
 176
 177                *num_parts = this_part + 1;
 178                alloc_size = *num_parts * sizeof(struct mtd_partition) +
 179                             extra_mem_size;
 180
 181                parts = kzalloc(alloc_size, GFP_KERNEL);
 182                if (!parts)
 183                        return ERR_PTR(-ENOMEM);
 184                extra_mem = (unsigned char *)(parts + *num_parts);
 185        }
 186
 187        /*
 188         * enter this partition (offset will be calculated later if it is
 189         * OFFSET_CONTINUOUS at this point)
 190         */
 191        parts[this_part].size = size;
 192        parts[this_part].offset = offset;
 193        parts[this_part].mask_flags = mask_flags;
 194        parts[this_part].add_flags = add_flags;
 195        if (name)
 196                strlcpy(extra_mem, name, name_len + 1);
 197        else
 198                sprintf(extra_mem, "Partition_%03d", this_part);
 199        parts[this_part].name = extra_mem;
 200        extra_mem += name_len + 1;
 201
 202        dbg(("partition %d: name <%s>, offset %llx, size %llx, mask flags %x\n",
 203             this_part, parts[this_part].name, parts[this_part].offset,
 204             parts[this_part].size, parts[this_part].mask_flags));
 205
 206        /* return (updated) pointer to extra_mem memory */
 207        if (extra_mem_ptr)
 208                *extra_mem_ptr = extra_mem;
 209
 210        /* return (updated) pointer command line string */
 211        *retptr = s;
 212
 213        /* return partition table */
 214        return parts;
 215}
 216
 217/*
 218 * Parse the command line.
 219 */
 220static int mtdpart_setup_real(char *s)
 221{
 222        cmdline_parsed = 1;
 223
 224        for( ; s != NULL; )
 225        {
 226                struct cmdline_mtd_partition *this_mtd;
 227                struct mtd_partition *parts;
 228                int mtd_id_len, num_parts;
 229                char *p, *mtd_id, *semicol, *open_parenth;
 230
 231                /*
 232                 * Replace the first ';' by a NULL char so strrchr can work
 233                 * properly.
 234                 */
 235                semicol = strchr(s, ';');
 236                if (semicol)
 237                        *semicol = '\0';
 238
 239                /*
 240                 * make sure that part-names with ":" will not be handled as
 241                 * part of the mtd-id with an ":"
 242                 */
 243                open_parenth = strchr(s, '(');
 244                if (open_parenth)
 245                        *open_parenth = '\0';
 246
 247                mtd_id = s;
 248
 249                /*
 250                 * fetch <mtd-id>. We use strrchr to ignore all ':' that could
 251                 * be present in the MTD name, only the last one is interpreted
 252                 * as an <mtd-id>/<part-definition> separator.
 253                 */
 254                p = strrchr(s, ':');
 255
 256                /* Restore the '(' now. */
 257                if (open_parenth)
 258                        *open_parenth = '(';
 259
 260                /* Restore the ';' now. */
 261                if (semicol)
 262                        *semicol = ';';
 263
 264                if (!p) {
 265                        pr_err("no mtd-id\n");
 266                        return -EINVAL;
 267                }
 268                mtd_id_len = p - mtd_id;
 269
 270                dbg(("parsing <%s>\n", p+1));
 271
 272                /*
 273                 * parse one mtd. have it reserve memory for the
 274                 * struct cmdline_mtd_partition and the mtd-id string.
 275                 */
 276                parts = newpart(p + 1,          /* cmdline */
 277                                &s,             /* out: updated cmdline ptr */
 278                                &num_parts,     /* out: number of parts */
 279                                0,              /* first partition */
 280                                (unsigned char**)&this_mtd, /* out: extra mem */
 281                                mtd_id_len + 1 + sizeof(*this_mtd) +
 282                                sizeof(void*)-1 /*alignment*/);
 283                if (IS_ERR(parts)) {
 284                        /*
 285                         * An error occurred. We're either:
 286                         * a) out of memory, or
 287                         * b) in the middle of the partition spec
 288                         * Either way, this mtd is hosed and we're
 289                         * unlikely to succeed in parsing any more
 290                         */
 291                         return PTR_ERR(parts);
 292                 }
 293
 294                /* align this_mtd */
 295                this_mtd = (struct cmdline_mtd_partition *)
 296                                ALIGN((unsigned long)this_mtd, sizeof(void *));
 297                /* enter results */
 298                this_mtd->parts = parts;
 299                this_mtd->num_parts = num_parts;
 300                this_mtd->mtd_id = (char*)(this_mtd + 1);
 301                strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
 302
 303                /* link into chain */
 304                this_mtd->next = partitions;
 305                partitions = this_mtd;
 306
 307                dbg(("mtdid=<%s> num_parts=<%d>\n",
 308                     this_mtd->mtd_id, this_mtd->num_parts));
 309
 310
 311                /* EOS - we're done */
 312                if (*s == 0)
 313                        break;
 314
 315                /* does another spec follow? */
 316                if (*s != ';') {
 317                        pr_err("bad character after partition (%c)\n", *s);
 318                        return -EINVAL;
 319                }
 320                s++;
 321        }
 322
 323        return 0;
 324}
 325
 326/*
 327 * Main function to be called from the MTD mapping driver/device to
 328 * obtain the partitioning information. At this point the command line
 329 * arguments will actually be parsed and turned to struct mtd_partition
 330 * information. It returns partitions for the requested mtd device, or
 331 * the first one in the chain if a NULL mtd_id is passed in.
 332 */
 333static int parse_cmdline_partitions(struct mtd_info *master,
 334                                    const struct mtd_partition **pparts,
 335                                    struct mtd_part_parser_data *data)
 336{
 337        unsigned long long offset;
 338        int i, err;
 339        struct cmdline_mtd_partition *part;
 340        const char *mtd_id = master->name;
 341
 342        /* parse command line */
 343        if (!cmdline_parsed) {
 344                err = mtdpart_setup_real(cmdline);
 345                if (err)
 346                        return err;
 347        }
 348
 349        /*
 350         * Search for the partition definition matching master->name.
 351         * If master->name is not set, stop at first partition definition.
 352         */
 353        for (part = partitions; part; part = part->next) {
 354                if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
 355                        break;
 356        }
 357
 358        if (!part)
 359                return 0;
 360
 361        for (i = 0, offset = 0; i < part->num_parts; i++) {
 362                if (part->parts[i].offset == OFFSET_CONTINUOUS)
 363                        part->parts[i].offset = offset;
 364                else
 365                        offset = part->parts[i].offset;
 366
 367                if (part->parts[i].size == SIZE_REMAINING)
 368                        part->parts[i].size = master->size - offset;
 369
 370                if (offset + part->parts[i].size > master->size) {
 371                        pr_warn("%s: partitioning exceeds flash size, truncating\n",
 372                                part->mtd_id);
 373                        part->parts[i].size = master->size - offset;
 374                }
 375                offset += part->parts[i].size;
 376
 377                if (part->parts[i].size == 0) {
 378                        pr_warn("%s: skipping zero sized partition\n",
 379                                part->mtd_id);
 380                        part->num_parts--;
 381                        memmove(&part->parts[i], &part->parts[i + 1],
 382                                sizeof(*part->parts) * (part->num_parts - i));
 383                        i--;
 384                }
 385        }
 386
 387        *pparts = kmemdup(part->parts, sizeof(*part->parts) * part->num_parts,
 388                          GFP_KERNEL);
 389        if (!*pparts)
 390                return -ENOMEM;
 391
 392        return part->num_parts;
 393}
 394
 395
 396/*
 397 * This is the handler for our kernel parameter, called from
 398 * main.c::checksetup(). Note that we can not yet kmalloc() anything,
 399 * so we only save the commandline for later processing.
 400 *
 401 * This function needs to be visible for bootloaders.
 402 */
 403static int __init mtdpart_setup(char *s)
 404{
 405        cmdline = s;
 406        return 1;
 407}
 408
 409__setup("mtdparts=", mtdpart_setup);
 410
 411static struct mtd_part_parser cmdline_parser = {
 412        .parse_fn = parse_cmdline_partitions,
 413        .name = "cmdlinepart",
 414};
 415
 416static int __init cmdline_parser_init(void)
 417{
 418        if (mtdparts)
 419                mtdpart_setup(mtdparts);
 420        register_mtd_parser(&cmdline_parser);
 421        return 0;
 422}
 423
 424static void __exit cmdline_parser_exit(void)
 425{
 426        deregister_mtd_parser(&cmdline_parser);
 427}
 428
 429module_init(cmdline_parser_init);
 430module_exit(cmdline_parser_exit);
 431
 432MODULE_PARM_DESC(mtdparts, "Partitioning specification");
 433module_param(mtdparts, charp, 0);
 434
 435MODULE_LICENSE("GPL");
 436MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
 437MODULE_DESCRIPTION("Command line configuration of MTD partitions");
 438