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