1 /*
2 * Read flash partition table from command line
3 *
4 * Copyright 2002 SYSGO Real-Time Solutions GmbH
5 *
6 * The format for the command line is as follows:
7 *
8 * mtdparts=<mtddef>[;<mtddef]
9 * <mtddef> := <mtd-id>:<partdef>[,<partdef>]
10 * where <mtd-id> is the name from the "cat /proc/mtd" command
11 * <partdef> := <size>[@offset][<name>][ro][lk]
12 * <mtd-id> := unique name used in mapping driver/device (mtd->name)
13 * <size> := standard linux memsize OR "-" to denote all remaining space
14 * <name> := '(' NAME ')'
15 *
16 * Examples:
17 *
18 * 1 NOR Flash, with 1 single writable partition:
19 * edb7312-nor:-
20 *
21 * 1 NOR Flash with 2 partitions, 1 NAND with one
22 * edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
23 */
24
25 #include <linux/kernel.h>
26 #include <linux/slab.h>
27
28 #include <linux/mtd/mtd.h>
29 #include <linux/mtd/partitions.h>
30 #include <linux/bootmem.h>
31
32 /* error message prefix */
33 #define ERRP "mtd: "
34
35 /* debug macro */
36 #if 0
37 #define dbg(x) do { printk("DEBUG-CMDLINE-PART: "); printk x; } while(0)
38 #else
39 #define dbg(x)
40 #endif
41
42
43 /* special size referring to all the remaining space in a partition */
44 #define SIZE_REMAINING UINT_MAX
45 #define OFFSET_CONTINUOUS UINT_MAX
46
47 struct cmdline_mtd_partition {
48 struct cmdline_mtd_partition *next;
49 char *mtd_id;
50 int num_parts;
51 struct mtd_partition *parts;
52 };
53
54 /* mtdpart_setup() parses into here */
55 static struct cmdline_mtd_partition *partitions;
56
57 /* the command line passed to mtdpart_setupd() */
58 static char *cmdline;
59 static int cmdline_parsed = 0;
60
61 /*
62 * Parse one partition definition for an MTD. Since there can be many
63 * comma separated partition definitions, this function calls itself
64 * recursively until no more partition definitions are found. Nice side
65 * effect: the memory to keep the mtd_partition structs and the names
66 * is allocated upon the last definition being found. At that point the
67 * syntax has been verified ok.
68 */
newpart(char * s,char ** retptr,int * num_parts,int this_part,unsigned char ** extra_mem_ptr,int extra_mem_size)69 static struct mtd_partition * newpart(char *s,
70 char **retptr,
71 int *num_parts,
72 int this_part,
73 unsigned char **extra_mem_ptr,
74 int extra_mem_size)
75 {
76 struct mtd_partition *parts;
77 unsigned long size;
78 unsigned long offset = OFFSET_CONTINUOUS;
79 char *name;
80 int name_len;
81 unsigned char *extra_mem;
82 char delim;
83 unsigned int mask_flags;
84
85 /* fetch the partition size */
86 if (*s == '-')
87 { /* assign all remaining space to this partition */
88 size = SIZE_REMAINING;
89 s++;
90 }
91 else
92 {
93 size = memparse(s, &s);
94 if (size < PAGE_SIZE)
95 {
96 printk(KERN_ERR ERRP "partition size too small (%lx)\n", size);
97 return NULL;
98 }
99 }
100
101 /* fetch partition name and flags */
102 mask_flags = 0; /* this is going to be a regular partition */
103 delim = 0;
104 /* check for offset */
105 if (*s == '@')
106 {
107 s++;
108 offset = memparse(s, &s);
109 }
110 /* now look for name */
111 if (*s == '(')
112 {
113 delim = ')';
114 }
115
116 if (delim)
117 {
118 char *p;
119
120 name = ++s;
121 p = strchr(name, delim);
122 if (!p)
123 {
124 printk(KERN_ERR ERRP "no closing %c found in partition name\n", delim);
125 return NULL;
126 }
127 name_len = p - name;
128 s = p + 1;
129 }
130 else
131 {
132 name = NULL;
133 name_len = 13; /* Partition_000 */
134 }
135
136 /* record name length for memory allocation later */
137 extra_mem_size += name_len + 1;
138
139 /* test for options */
140 if (strncmp(s, "ro", 2) == 0)
141 {
142 mask_flags |= MTD_WRITEABLE;
143 s += 2;
144 }
145
146 /* if lk is found do NOT unlock the MTD partition*/
147 if (strncmp(s, "lk", 2) == 0)
148 {
149 mask_flags |= MTD_POWERUP_LOCK;
150 s += 2;
151 }
152
153 /* test if more partitions are following */
154 if (*s == ',')
155 {
156 if (size == SIZE_REMAINING)
157 {
158 printk(KERN_ERR ERRP "no partitions allowed after a fill-up partition\n");
159 return NULL;
160 }
161 /* more partitions follow, parse them */
162 parts = newpart(s + 1, &s, num_parts, this_part + 1,
163 &extra_mem, extra_mem_size);
164 if (!parts)
165 return NULL;
166 }
167 else
168 { /* this is the last partition: allocate space for all */
169 int alloc_size;
170
171 *num_parts = this_part + 1;
172 alloc_size = *num_parts * sizeof(struct mtd_partition) +
173 extra_mem_size;
174 parts = kzalloc(alloc_size, GFP_KERNEL);
175 if (!parts)
176 {
177 printk(KERN_ERR ERRP "out of memory\n");
178 return NULL;
179 }
180 extra_mem = (unsigned char *)(parts + *num_parts);
181 }
182 /* enter this partition (offset will be calculated later if it is zero at this point) */
183 parts[this_part].size = size;
184 parts[this_part].offset = offset;
185 parts[this_part].mask_flags = mask_flags;
186 if (name)
187 {
188 strlcpy(extra_mem, name, name_len + 1);
189 }
190 else
191 {
192 sprintf(extra_mem, "Partition_%03d", this_part);
193 }
194 parts[this_part].name = extra_mem;
195 extra_mem += name_len + 1;
196
197 dbg(("partition %d: name <%s>, offset %x, size %x, mask flags %x\n",
198 this_part,
199 parts[this_part].name,
200 parts[this_part].offset,
201 parts[this_part].size,
202 parts[this_part].mask_flags));
203
204 /* return (updated) pointer to extra_mem memory */
205 if (extra_mem_ptr)
206 *extra_mem_ptr = extra_mem;
207
208 /* return (updated) pointer command line string */
209 *retptr = s;
210
211 /* return partition table */
212 return parts;
213 }
214
215 /*
216 * Parse the command line.
217 */
mtdpart_setup_real(char * s)218 static int mtdpart_setup_real(char *s)
219 {
220 cmdline_parsed = 1;
221
222 for( ; s != NULL; )
223 {
224 struct cmdline_mtd_partition *this_mtd;
225 struct mtd_partition *parts;
226 int mtd_id_len;
227 int num_parts;
228 char *p, *mtd_id;
229
230 mtd_id = s;
231 /* fetch <mtd-id> */
232 if (!(p = strchr(s, ':')))
233 {
234 printk(KERN_ERR ERRP "no mtd-id\n");
235 return 0;
236 }
237 mtd_id_len = p - mtd_id;
238
239 dbg(("parsing <%s>\n", p+1));
240
241 /*
242 * parse one mtd. have it reserve memory for the
243 * struct cmdline_mtd_partition and the mtd-id string.
244 */
245 parts = newpart(p + 1, /* cmdline */
246 &s, /* out: updated cmdline ptr */
247 &num_parts, /* out: number of parts */
248 0, /* first partition */
249 (unsigned char**)&this_mtd, /* out: extra mem */
250 mtd_id_len + 1 + sizeof(*this_mtd) +
251 sizeof(void*)-1 /*alignment*/);
252 if(!parts)
253 {
254 /*
255 * An error occurred. We're either:
256 * a) out of memory, or
257 * b) in the middle of the partition spec
258 * Either way, this mtd is hosed and we're
259 * unlikely to succeed in parsing any more
260 */
261 return 0;
262 }
263
264 /* align this_mtd */
265 this_mtd = (struct cmdline_mtd_partition *)
266 ALIGN((unsigned long)this_mtd, sizeof(void*));
267 /* enter results */
268 this_mtd->parts = parts;
269 this_mtd->num_parts = num_parts;
270 this_mtd->mtd_id = (char*)(this_mtd + 1);
271 strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
272
273 /* link into chain */
274 this_mtd->next = partitions;
275 partitions = this_mtd;
276
277 dbg(("mtdid=<%s> num_parts=<%d>\n",
278 this_mtd->mtd_id, this_mtd->num_parts));
279
280
281 /* EOS - we're done */
282 if (*s == 0)
283 break;
284
285 /* does another spec follow? */
286 if (*s != ';')
287 {
288 printk(KERN_ERR ERRP "bad character after partition (%c)\n", *s);
289 return 0;
290 }
291 s++;
292 }
293 return 1;
294 }
295
296 /*
297 * Main function to be called from the MTD mapping driver/device to
298 * obtain the partitioning information. At this point the command line
299 * arguments will actually be parsed and turned to struct mtd_partition
300 * information. It returns partitions for the requested mtd device, or
301 * the first one in the chain if a NULL mtd_id is passed in.
302 */
parse_cmdline_partitions(struct mtd_info * master,struct mtd_partition ** pparts,unsigned long origin)303 static int parse_cmdline_partitions(struct mtd_info *master,
304 struct mtd_partition **pparts,
305 unsigned long origin)
306 {
307 unsigned long offset;
308 int i;
309 struct cmdline_mtd_partition *part;
310 const char *mtd_id = master->name;
311
312 /* parse command line */
313 if (!cmdline_parsed)
314 mtdpart_setup_real(cmdline);
315
316 for(part = partitions; part; part = part->next)
317 {
318 if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
319 {
320 for(i = 0, offset = 0; i < part->num_parts; i++)
321 {
322 if (part->parts[i].offset == OFFSET_CONTINUOUS)
323 part->parts[i].offset = offset;
324 else
325 offset = part->parts[i].offset;
326 if (part->parts[i].size == SIZE_REMAINING)
327 part->parts[i].size = master->size - offset;
328 if (offset + part->parts[i].size > master->size)
329 {
330 printk(KERN_WARNING ERRP
331 "%s: partitioning exceeds flash size, truncating\n",
332 part->mtd_id);
333 part->parts[i].size = master->size - offset;
334 part->num_parts = i;
335 }
336 offset += part->parts[i].size;
337 }
338 *pparts = part->parts;
339 return part->num_parts;
340 }
341 }
342 return 0;
343 }
344
345
346 /*
347 * This is the handler for our kernel parameter, called from
348 * main.c::checksetup(). Note that we can not yet kmalloc() anything,
349 * so we only save the commandline for later processing.
350 *
351 * This function needs to be visible for bootloaders.
352 */
mtdpart_setup(char * s)353 static int mtdpart_setup(char *s)
354 {
355 cmdline = s;
356 return 1;
357 }
358
359 __setup("mtdparts=", mtdpart_setup);
360
361 static struct mtd_part_parser cmdline_parser = {
362 .owner = THIS_MODULE,
363 .parse_fn = parse_cmdline_partitions,
364 .name = "cmdlinepart",
365 };
366
cmdline_parser_init(void)367 static int __init cmdline_parser_init(void)
368 {
369 return register_mtd_parser(&cmdline_parser);
370 }
371
372 module_init(cmdline_parser_init);
373
374 MODULE_LICENSE("GPL");
375 MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
376 MODULE_DESCRIPTION("Command line configuration of MTD partitions");
377