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 * where <mtd-id> is the name from the "cat /proc/mtd" command
26 * <partdef> := <size>[@offset][<name>][ro][lk]
27 * <mtd-id> := unique name used in mapping driver/device (mtd->name)
28 * <size> := standard linux memsize OR "-" to denote all remaining space
29 * <name> := '(' NAME ')'
30 *
31 * Examples:
32 *
33 * 1 NOR Flash, with 1 single writable partition:
34 * edb7312-nor:-
35 *
36 * 1 NOR Flash with 2 partitions, 1 NAND with one
37 * edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
38 */
39
40 #include <linux/kernel.h>
41 #include <linux/slab.h>
42
43 #include <linux/mtd/mtd.h>
44 #include <linux/mtd/partitions.h>
45 #include <linux/bootmem.h>
46 #include <linux/module.h>
47
48 /* error message prefix */
49 #define ERRP "mtd: "
50
51 /* debug macro */
52 #if 0
53 #define dbg(x) do { printk("DEBUG-CMDLINE-PART: "); printk x; } while(0)
54 #else
55 #define dbg(x)
56 #endif
57
58
59 /* special size referring to all the remaining space in a partition */
60 #define SIZE_REMAINING UINT_MAX
61 #define OFFSET_CONTINUOUS UINT_MAX
62
63 struct cmdline_mtd_partition {
64 struct cmdline_mtd_partition *next;
65 char *mtd_id;
66 int num_parts;
67 struct mtd_partition *parts;
68 };
69
70 /* mtdpart_setup() parses into here */
71 static struct cmdline_mtd_partition *partitions;
72
73 /* the command line passed to mtdpart_setupd() */
74 static char *cmdline;
75 static int cmdline_parsed = 0;
76
77 /*
78 * Parse one partition definition for an MTD. Since there can be many
79 * comma separated partition definitions, this function calls itself
80 * recursively until no more partition definitions are found. Nice side
81 * effect: the memory to keep the mtd_partition structs and the names
82 * is allocated upon the last definition being found. At that point the
83 * syntax has been verified ok.
84 */
newpart(char * s,char ** retptr,int * num_parts,int this_part,unsigned char ** extra_mem_ptr,int extra_mem_size)85 static struct mtd_partition * newpart(char *s,
86 char **retptr,
87 int *num_parts,
88 int this_part,
89 unsigned char **extra_mem_ptr,
90 int extra_mem_size)
91 {
92 struct mtd_partition *parts;
93 unsigned long size;
94 unsigned long offset = OFFSET_CONTINUOUS;
95 char *name;
96 int name_len;
97 unsigned char *extra_mem;
98 char delim;
99 unsigned int mask_flags;
100
101 /* fetch the partition size */
102 if (*s == '-')
103 { /* assign all remaining space to this partition */
104 size = SIZE_REMAINING;
105 s++;
106 }
107 else
108 {
109 size = memparse(s, &s);
110 if (size < PAGE_SIZE)
111 {
112 printk(KERN_ERR ERRP "partition size too small (%lx)\n", size);
113 return NULL;
114 }
115 }
116
117 /* fetch partition name and flags */
118 mask_flags = 0; /* this is going to be a regular partition */
119 delim = 0;
120 /* check for offset */
121 if (*s == '@')
122 {
123 s++;
124 offset = memparse(s, &s);
125 }
126 /* now look for name */
127 if (*s == '(')
128 {
129 delim = ')';
130 }
131
132 if (delim)
133 {
134 char *p;
135
136 name = ++s;
137 p = strchr(name, delim);
138 if (!p)
139 {
140 printk(KERN_ERR ERRP "no closing %c found in partition name\n", delim);
141 return NULL;
142 }
143 name_len = p - name;
144 s = p + 1;
145 }
146 else
147 {
148 name = NULL;
149 name_len = 13; /* Partition_000 */
150 }
151
152 /* record name length for memory allocation later */
153 extra_mem_size += name_len + 1;
154
155 /* test for options */
156 if (strncmp(s, "ro", 2) == 0)
157 {
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 {
165 mask_flags |= MTD_POWERUP_LOCK;
166 s += 2;
167 }
168
169 /* test if more partitions are following */
170 if (*s == ',')
171 {
172 if (size == SIZE_REMAINING)
173 {
174 printk(KERN_ERR ERRP "no partitions allowed after a fill-up partition\n");
175 return NULL;
176 }
177 /* more partitions follow, parse them */
178 parts = newpart(s + 1, &s, num_parts, this_part + 1,
179 &extra_mem, extra_mem_size);
180 if (!parts)
181 return NULL;
182 }
183 else
184 { /* this is the last partition: allocate space for all */
185 int alloc_size;
186
187 *num_parts = this_part + 1;
188 alloc_size = *num_parts * sizeof(struct mtd_partition) +
189 extra_mem_size;
190 parts = kzalloc(alloc_size, GFP_KERNEL);
191 if (!parts)
192 return NULL;
193 extra_mem = (unsigned char *)(parts + *num_parts);
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 {
201 strlcpy(extra_mem, name, name_len + 1);
202 }
203 else
204 {
205 sprintf(extra_mem, "Partition_%03d", this_part);
206 }
207 parts[this_part].name = extra_mem;
208 extra_mem += name_len + 1;
209
210 dbg(("partition %d: name <%s>, offset %llx, size %llx, mask flags %x\n",
211 this_part,
212 parts[this_part].name,
213 parts[this_part].offset,
214 parts[this_part].size,
215 parts[this_part].mask_flags));
216
217 /* return (updated) pointer to extra_mem memory */
218 if (extra_mem_ptr)
219 *extra_mem_ptr = extra_mem;
220
221 /* return (updated) pointer command line string */
222 *retptr = s;
223
224 /* return partition table */
225 return parts;
226 }
227
228 /*
229 * Parse the command line.
230 */
mtdpart_setup_real(char * s)231 static int mtdpart_setup_real(char *s)
232 {
233 cmdline_parsed = 1;
234
235 for( ; s != NULL; )
236 {
237 struct cmdline_mtd_partition *this_mtd;
238 struct mtd_partition *parts;
239 int mtd_id_len;
240 int num_parts;
241 char *p, *mtd_id;
242
243 mtd_id = s;
244 /* fetch <mtd-id> */
245 if (!(p = strchr(s, ':')))
246 {
247 printk(KERN_ERR ERRP "no mtd-id\n");
248 return 0;
249 }
250 mtd_id_len = p - mtd_id;
251
252 dbg(("parsing <%s>\n", p+1));
253
254 /*
255 * parse one mtd. have it reserve memory for the
256 * struct cmdline_mtd_partition and the mtd-id string.
257 */
258 parts = newpart(p + 1, /* cmdline */
259 &s, /* out: updated cmdline ptr */
260 &num_parts, /* out: number of parts */
261 0, /* first partition */
262 (unsigned char**)&this_mtd, /* out: extra mem */
263 mtd_id_len + 1 + sizeof(*this_mtd) +
264 sizeof(void*)-1 /*alignment*/);
265 if(!parts)
266 {
267 /*
268 * An error occurred. We're either:
269 * a) out of memory, or
270 * b) in the middle of the partition spec
271 * Either way, this mtd is hosed and we're
272 * unlikely to succeed in parsing any more
273 */
274 return 0;
275 }
276
277 /* align this_mtd */
278 this_mtd = (struct cmdline_mtd_partition *)
279 ALIGN((unsigned long)this_mtd, sizeof(void*));
280 /* enter results */
281 this_mtd->parts = parts;
282 this_mtd->num_parts = num_parts;
283 this_mtd->mtd_id = (char*)(this_mtd + 1);
284 strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
285
286 /* link into chain */
287 this_mtd->next = partitions;
288 partitions = this_mtd;
289
290 dbg(("mtdid=<%s> num_parts=<%d>\n",
291 this_mtd->mtd_id, this_mtd->num_parts));
292
293
294 /* EOS - we're done */
295 if (*s == 0)
296 break;
297
298 /* does another spec follow? */
299 if (*s != ';')
300 {
301 printk(KERN_ERR ERRP "bad character after partition (%c)\n", *s);
302 return 0;
303 }
304 s++;
305 }
306 return 1;
307 }
308
309 /*
310 * Main function to be called from the MTD mapping driver/device to
311 * obtain the partitioning information. At this point the command line
312 * arguments will actually be parsed and turned to struct mtd_partition
313 * information. It returns partitions for the requested mtd device, or
314 * the first one in the chain if a NULL mtd_id is passed in.
315 */
parse_cmdline_partitions(struct mtd_info * master,struct mtd_partition ** pparts,struct mtd_part_parser_data * data)316 static int parse_cmdline_partitions(struct mtd_info *master,
317 struct mtd_partition **pparts,
318 struct mtd_part_parser_data *data)
319 {
320 unsigned long offset;
321 int i;
322 struct cmdline_mtd_partition *part;
323 const char *mtd_id = master->name;
324
325 /* parse command line */
326 if (!cmdline_parsed)
327 mtdpart_setup_real(cmdline);
328
329 for(part = partitions; part; part = part->next)
330 {
331 if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
332 {
333 for(i = 0, offset = 0; i < part->num_parts; i++)
334 {
335 if (part->parts[i].offset == OFFSET_CONTINUOUS)
336 part->parts[i].offset = offset;
337 else
338 offset = part->parts[i].offset;
339 if (part->parts[i].size == SIZE_REMAINING)
340 part->parts[i].size = master->size - offset;
341 if (offset + part->parts[i].size > master->size)
342 {
343 printk(KERN_WARNING ERRP
344 "%s: partitioning exceeds flash size, truncating\n",
345 part->mtd_id);
346 part->parts[i].size = master->size - offset;
347 part->num_parts = i;
348 }
349 offset += part->parts[i].size;
350 }
351 *pparts = kmemdup(part->parts,
352 sizeof(*part->parts) * part->num_parts,
353 GFP_KERNEL);
354 if (!*pparts)
355 return -ENOMEM;
356 return part->num_parts;
357 }
358 }
359 return 0;
360 }
361
362
363 /*
364 * This is the handler for our kernel parameter, called from
365 * main.c::checksetup(). Note that we can not yet kmalloc() anything,
366 * so we only save the commandline for later processing.
367 *
368 * This function needs to be visible for bootloaders.
369 */
mtdpart_setup(char * s)370 static int mtdpart_setup(char *s)
371 {
372 cmdline = s;
373 return 1;
374 }
375
376 __setup("mtdparts=", mtdpart_setup);
377
378 static struct mtd_part_parser cmdline_parser = {
379 .owner = THIS_MODULE,
380 .parse_fn = parse_cmdline_partitions,
381 .name = "cmdlinepart",
382 };
383
cmdline_parser_init(void)384 static int __init cmdline_parser_init(void)
385 {
386 return register_mtd_parser(&cmdline_parser);
387 }
388
389 module_init(cmdline_parser_init);
390
391 MODULE_LICENSE("GPL");
392 MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
393 MODULE_DESCRIPTION("Command line configuration of MTD partitions");
394