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 */
newpart(char * s,char ** retptr,int * num_parts,int this_part,unsigned char ** extra_mem_ptr,int extra_mem_size)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 /*
194 * enter this partition (offset will be calculated later if it is
195 * OFFSET_CONTINUOUS at this point)
196 */
197 parts[this_part].size = size;
198 parts[this_part].offset = offset;
199 parts[this_part].mask_flags = mask_flags;
200 if (name)
201 strlcpy(extra_mem, name, name_len + 1);
202 else
203 sprintf(extra_mem, "Partition_%03d", this_part);
204 parts[this_part].name = extra_mem;
205 extra_mem += name_len + 1;
206
207 dbg(("partition %d: name <%s>, offset %llx, size %llx, mask flags %x\n",
208 this_part, parts[this_part].name, parts[this_part].offset,
209 parts[this_part].size, parts[this_part].mask_flags));
210
211 /* return (updated) pointer to extra_mem memory */
212 if (extra_mem_ptr)
213 *extra_mem_ptr = extra_mem;
214
215 /* return (updated) pointer command line string */
216 *retptr = s;
217
218 /* return partition table */
219 return parts;
220 }
221
222 /*
223 * Parse the command line.
224 */
mtdpart_setup_real(char * s)225 static int mtdpart_setup_real(char *s)
226 {
227 cmdline_parsed = 1;
228
229 for( ; s != NULL; )
230 {
231 struct cmdline_mtd_partition *this_mtd;
232 struct mtd_partition *parts;
233 int mtd_id_len, num_parts;
234 char *p, *mtd_id;
235
236 mtd_id = s;
237
238 /* fetch <mtd-id> */
239 p = strchr(s, ':');
240 if (!p) {
241 pr_err("no mtd-id\n");
242 return -EINVAL;
243 }
244 mtd_id_len = p - mtd_id;
245
246 dbg(("parsing <%s>\n", p+1));
247
248 /*
249 * parse one mtd. have it reserve memory for the
250 * struct cmdline_mtd_partition and the mtd-id string.
251 */
252 parts = newpart(p + 1, /* cmdline */
253 &s, /* out: updated cmdline ptr */
254 &num_parts, /* out: number of parts */
255 0, /* first partition */
256 (unsigned char**)&this_mtd, /* out: extra mem */
257 mtd_id_len + 1 + sizeof(*this_mtd) +
258 sizeof(void*)-1 /*alignment*/);
259 if (IS_ERR(parts)) {
260 /*
261 * An error occurred. We're either:
262 * a) out of memory, or
263 * b) in the middle of the partition spec
264 * Either way, this mtd is hosed and we're
265 * unlikely to succeed in parsing any more
266 */
267 return PTR_ERR(parts);
268 }
269
270 /* align this_mtd */
271 this_mtd = (struct cmdline_mtd_partition *)
272 ALIGN((unsigned long)this_mtd, sizeof(void *));
273 /* enter results */
274 this_mtd->parts = parts;
275 this_mtd->num_parts = num_parts;
276 this_mtd->mtd_id = (char*)(this_mtd + 1);
277 strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
278
279 /* link into chain */
280 this_mtd->next = partitions;
281 partitions = this_mtd;
282
283 dbg(("mtdid=<%s> num_parts=<%d>\n",
284 this_mtd->mtd_id, this_mtd->num_parts));
285
286
287 /* EOS - we're done */
288 if (*s == 0)
289 break;
290
291 /* does another spec follow? */
292 if (*s != ';') {
293 pr_err("bad character after partition (%c)\n", *s);
294 return -EINVAL;
295 }
296 s++;
297 }
298
299 return 0;
300 }
301
302 /*
303 * Main function to be called from the MTD mapping driver/device to
304 * obtain the partitioning information. At this point the command line
305 * arguments will actually be parsed and turned to struct mtd_partition
306 * information. It returns partitions for the requested mtd device, or
307 * the first one in the chain if a NULL mtd_id is passed in.
308 */
parse_cmdline_partitions(struct mtd_info * master,const struct mtd_partition ** pparts,struct mtd_part_parser_data * data)309 static int parse_cmdline_partitions(struct mtd_info *master,
310 const struct mtd_partition **pparts,
311 struct mtd_part_parser_data *data)
312 {
313 unsigned long long offset;
314 int i, err;
315 struct cmdline_mtd_partition *part;
316 const char *mtd_id = master->name;
317
318 /* parse command line */
319 if (!cmdline_parsed) {
320 err = mtdpart_setup_real(cmdline);
321 if (err)
322 return err;
323 }
324
325 /*
326 * Search for the partition definition matching master->name.
327 * If master->name is not set, stop at first partition definition.
328 */
329 for (part = partitions; part; part = part->next) {
330 if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
331 break;
332 }
333
334 if (!part)
335 return 0;
336
337 for (i = 0, offset = 0; i < part->num_parts; i++) {
338 if (part->parts[i].offset == OFFSET_CONTINUOUS)
339 part->parts[i].offset = offset;
340 else
341 offset = part->parts[i].offset;
342
343 if (part->parts[i].size == SIZE_REMAINING)
344 part->parts[i].size = master->size - offset;
345
346 if (offset + part->parts[i].size > master->size) {
347 pr_warn("%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 pr_warn("%s: skipping zero sized partition\n",
355 part->mtd_id);
356 part->num_parts--;
357 memmove(&part->parts[i], &part->parts[i + 1],
358 sizeof(*part->parts) * (part->num_parts - i));
359 i--;
360 }
361 }
362
363 *pparts = kmemdup(part->parts, sizeof(*part->parts) * part->num_parts,
364 GFP_KERNEL);
365 if (!*pparts)
366 return -ENOMEM;
367
368 return part->num_parts;
369 }
370
371
372 /*
373 * This is the handler for our kernel parameter, called from
374 * main.c::checksetup(). Note that we can not yet kmalloc() anything,
375 * so we only save the commandline for later processing.
376 *
377 * This function needs to be visible for bootloaders.
378 */
mtdpart_setup(char * s)379 static int __init mtdpart_setup(char *s)
380 {
381 cmdline = s;
382 return 1;
383 }
384
385 __setup("mtdparts=", mtdpart_setup);
386
387 static struct mtd_part_parser cmdline_parser = {
388 .parse_fn = parse_cmdline_partitions,
389 .name = "cmdlinepart",
390 };
391
cmdline_parser_init(void)392 static int __init cmdline_parser_init(void)
393 {
394 if (mtdparts)
395 mtdpart_setup(mtdparts);
396 register_mtd_parser(&cmdline_parser);
397 return 0;
398 }
399
cmdline_parser_exit(void)400 static void __exit cmdline_parser_exit(void)
401 {
402 deregister_mtd_parser(&cmdline_parser);
403 }
404
405 module_init(cmdline_parser_init);
406 module_exit(cmdline_parser_exit);
407
408 MODULE_PARM_DESC(mtdparts, "Partitioning specification");
409 module_param(mtdparts, charp, 0);
410
411 MODULE_LICENSE("GPL");
412 MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
413 MODULE_DESCRIPTION("Command line configuration of MTD partitions");
414
