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Linux/drivers/mtd/cmdlinepart.c

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

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