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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Read flash partition table from command line4 *5 * Copyright © 2002 SYSGO Real-Time Solutions GmbH6 * Copyright © 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 space15 * size is automatically truncated at end of device16 * if specified or truncated size is 0 the part is skipped17 * <offset> := standard linux memsize18 * if omitted the part will immediately follow the previous part19 * or 0 if the first part20 * <name> := '(' NAME ')'21 * NAME will appear in /proc/mtd22 *23 * <size> and <offset> can be specified such that the parts are out of order24 * in physical memory and may even overlap.25 *26 * The parts are assigned MTD numbers in the order they are specified in the27 * 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 one35 * edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)36 */37 38#define pr_fmt(fmt) "mtd: " fmt39 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/* special size referring to all the remaining space in a partition */48#define SIZE_REMAINING ULLONG_MAX49#define OFFSET_CONTINUOUS ULLONG_MAX50 51struct cmdline_mtd_partition {52 struct cmdline_mtd_partition *next;53 char *mtd_id;54 int num_parts;55 struct mtd_partition *parts;56};57 58/* mtdpart_setup() parses into here */59static struct cmdline_mtd_partition *partitions;60 61/* the command line passed to mtdpart_setup() */62static char *mtdparts;63static char *cmdline;64static int cmdline_parsed;65 66/*67 * Parse one partition definition for an MTD. Since there can be many68 * comma separated partition definitions, this function calls itself69 * recursively until no more partition definitions are found. Nice side70 * effect: the memory to keep the mtd_partition structs and the names71 * is allocated upon the last definition being found. At that point the72 * syntax has been verified ok.73 */74static struct mtd_partition * newpart(char *s,75 char **retptr,76 int *num_parts,77 int this_part,78 unsigned char **extra_mem_ptr,79 int extra_mem_size)80{81 struct mtd_partition *parts;82 unsigned long long size, offset = OFFSET_CONTINUOUS;83 char *name;84 int name_len;85 unsigned char *extra_mem;86 char delim;87 unsigned int mask_flags, add_flags;88 89 /* fetch the partition size */90 if (*s == '-') {91 /* assign all remaining space to this partition */92 size = SIZE_REMAINING;93 s++;94 } else {95 size = memparse(s, &s);96 if (!size) {97 pr_err("partition has size 0\n");98 return ERR_PTR(-EINVAL);99 }100 }101 102 /* fetch partition name and flags */103 mask_flags = 0; /* this is going to be a regular partition */104 add_flags = 0;105 delim = 0;106 107 /* check for offset */108 if (*s == '@') {109 s++;110 offset = memparse(s, &s);111 }112 113 /* now look for name */114 if (*s == '(')115 delim = ')';116 117 if (delim) {118 char *p;119 120 name = ++s;121 p = strchr(name, delim);122 if (!p) {123 pr_err("no closing %c found in partition name\n", delim);124 return ERR_PTR(-EINVAL);125 }126 name_len = p - name;127 s = p + 1;128 } else {129 name = NULL;130 name_len = 13; /* Partition_000 */131 }132 133 /* record name length for memory allocation later */134 extra_mem_size += name_len + 1;135 136 /* test for options */137 if (strncmp(s, "ro", 2) == 0) {138 mask_flags |= MTD_WRITEABLE;139 s += 2;140 }141 142 /* if lk is found do NOT unlock the MTD partition*/143 if (strncmp(s, "lk", 2) == 0) {144 mask_flags |= MTD_POWERUP_LOCK;145 s += 2;146 }147 148 /* if slc is found use emulated SLC mode on this partition*/149 if (!strncmp(s, "slc", 3)) {150 add_flags |= MTD_SLC_ON_MLC_EMULATION;151 s += 3;152 }153 154 /* test if more partitions are following */155 if (*s == ',') {156 if (size == SIZE_REMAINING) {157 pr_err("no partitions allowed after a fill-up partition\n");158 return ERR_PTR(-EINVAL);159 }160 /* more partitions follow, parse them */161 parts = newpart(s + 1, &s, num_parts, this_part + 1,162 &extra_mem, extra_mem_size);163 if (IS_ERR(parts))164 return parts;165 } else {166 /* this is the last partition: allocate space for all */167 int alloc_size;168 169 *num_parts = this_part + 1;170 alloc_size = *num_parts * sizeof(struct mtd_partition) +171 extra_mem_size;172 173 parts = kzalloc(alloc_size, GFP_KERNEL);174 if (!parts)175 return ERR_PTR(-ENOMEM);176 extra_mem = (unsigned char *)(parts + *num_parts);177 }178 179 /*180 * enter this partition (offset will be calculated later if it is181 * OFFSET_CONTINUOUS at this point)182 */183 parts[this_part].size = size;184 parts[this_part].offset = offset;185 parts[this_part].mask_flags = mask_flags;186 parts[this_part].add_flags = add_flags;187 if (name)188 strscpy(extra_mem, name, name_len + 1);189 else190 sprintf(extra_mem, "Partition_%03d", this_part);191 parts[this_part].name = extra_mem;192 extra_mem += name_len + 1;193 194 pr_debug("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, *semicol, *open_parenth;222 223 /*224 * Replace the first ';' by a NULL char so strrchr can work225 * properly.226 */227 semicol = strchr(s, ';');228 if (semicol)229 *semicol = '\0';230 231 /*232 * make sure that part-names with ":" will not be handled as233 * part of the mtd-id with an ":"234 */235 open_parenth = strchr(s, '(');236 if (open_parenth)237 *open_parenth = '\0';238 239 mtd_id = s;240 241 /*242 * fetch <mtd-id>. We use strrchr to ignore all ':' that could243 * be present in the MTD name, only the last one is interpreted244 * as an <mtd-id>/<part-definition> separator.245 */246 p = strrchr(s, ':');247 248 /* Restore the '(' now. */249 if (open_parenth)250 *open_parenth = '(';251 252 /* Restore the ';' now. */253 if (semicol)254 *semicol = ';';255 256 if (!p) {257 pr_err("no mtd-id\n");258 return -EINVAL;259 }260 mtd_id_len = p - mtd_id;261 262 pr_debug("parsing <%s>\n", p+1);263 264 /*265 * parse one mtd. have it reserve memory for the266 * struct cmdline_mtd_partition and the mtd-id string.267 */268 parts = newpart(p + 1, /* cmdline */269 &s, /* out: updated cmdline ptr */270 &num_parts, /* out: number of parts */271 0, /* first partition */272 (unsigned char**)&this_mtd, /* out: extra mem */273 mtd_id_len + 1 + sizeof(*this_mtd) +274 sizeof(void*)-1 /*alignment*/);275 if (IS_ERR(parts)) {276 /*277 * An error occurred. We're either:278 * a) out of memory, or279 * b) in the middle of the partition spec280 * Either way, this mtd is hosed and we're281 * unlikely to succeed in parsing any more282 */283 return PTR_ERR(parts);284 }285 286 /* align this_mtd */287 this_mtd = (struct cmdline_mtd_partition *)288 ALIGN((unsigned long)this_mtd, sizeof(void *));289 /* enter results */290 this_mtd->parts = parts;291 this_mtd->num_parts = num_parts;292 this_mtd->mtd_id = (char*)(this_mtd + 1);293 strscpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);294 295 /* link into chain */296 this_mtd->next = partitions;297 partitions = this_mtd;298 299 pr_debug("mtdid=<%s> num_parts=<%d>\n",300 this_mtd->mtd_id, this_mtd->num_parts);301 302 303 /* EOS - we're done */304 if (*s == 0)305 break;306 307 /* does another spec follow? */308 if (*s != ';') {309 pr_err("bad character after partition (%c)\n", *s);310 return -EINVAL;311 }312 s++;313 }314 315 return 0;316}317 318/*319 * Main function to be called from the MTD mapping driver/device to320 * obtain the partitioning information. At this point the command line321 * arguments will actually be parsed and turned to struct mtd_partition322 * information. It returns partitions for the requested mtd device, or323 * the first one in the chain if a NULL mtd_id is passed in.324 */325static int parse_cmdline_partitions(struct mtd_info *master,326 const struct mtd_partition **pparts,327 struct mtd_part_parser_data *data)328{329 unsigned long long offset;330 int i, err;331 struct cmdline_mtd_partition *part;332 const char *mtd_id = master->name;333 334 /* parse command line */335 if (!cmdline_parsed) {336 err = mtdpart_setup_real(cmdline);337 if (err)338 return err;339 }340 341 /*342 * Search for the partition definition matching master->name.343 * If master->name is not set, stop at first partition definition.344 */345 for (part = partitions; part; part = part->next) {346 if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))347 break;348 }349 350 if (!part)351 return 0;352 353 for (i = 0, offset = 0; i < part->num_parts; i++) {354 if (part->parts[i].offset == OFFSET_CONTINUOUS)355 part->parts[i].offset = offset;356 else357 offset = part->parts[i].offset;358 359 if (part->parts[i].size == SIZE_REMAINING)360 part->parts[i].size = master->size - offset;361 362 if (offset + part->parts[i].size > master->size) {363 pr_warn("%s: partitioning exceeds flash size, truncating\n",364 part->mtd_id);365 part->parts[i].size = master->size - offset;366 }367 offset += part->parts[i].size;368 369 if (part->parts[i].size == 0) {370 pr_warn("%s: skipping zero sized partition\n",371 part->mtd_id);372 part->num_parts--;373 memmove(&part->parts[i], &part->parts[i + 1],374 sizeof(*part->parts) * (part->num_parts - i));375 i--;376 }377 }378 379 *pparts = kmemdup(part->parts, sizeof(*part->parts) * part->num_parts,380 GFP_KERNEL);381 if (!*pparts)382 return -ENOMEM;383 384 return part->num_parts;385}386 387 388/*389 * This is the handler for our kernel parameter, called from390 * main.c::checksetup(). Note that we can not yet kmalloc() anything,391 * so we only save the commandline for later processing.392 *393 * This function needs to be visible for bootloaders.394 */395static int __init mtdpart_setup(char *s)396{397 cmdline = s;398 return 1;399}400 401__setup("mtdparts=", mtdpart_setup);402 403static struct mtd_part_parser cmdline_parser = {404 .parse_fn = parse_cmdline_partitions,405 .name = "cmdlinepart",406};407 408static int __init cmdline_parser_init(void)409{410 if (mtdparts)411 mtdpart_setup(mtdparts);412 register_mtd_parser(&cmdline_parser);413 return 0;414}415 416static void __exit cmdline_parser_exit(void)417{418 deregister_mtd_parser(&cmdline_parser);419}420 421module_init(cmdline_parser_init);422module_exit(cmdline_parser_exit);423 424MODULE_PARM_DESC(mtdparts, "Partitioning specification");425module_param(mtdparts, charp, 0);426 427MODULE_LICENSE("GPL");428MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");429MODULE_DESCRIPTION("Command line configuration of MTD partitions");430