1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Read flash partition table from command line
4 *
5 * Copyright © 2002 SYSGO Real-Time Solutions GmbH
6 * Copyright © 2002-2010 David Woodhouse <dwmw2@infradead.org>
7 *
8 * The format for the command line is as follows:
9 *
10 * mtdparts=<mtddef>[;<mtddef]
11 * <mtddef> := <mtd-id>:<partdef>[,<partdef>]
12 * <partdef> := <size>[@<offset>][<name>][ro][lk]
13 * <mtd-id> := unique name used in mapping driver/device (mtd->name)
14 * <size> := standard linux memsize OR "-" to denote all remaining space
15 * size is automatically truncated at end of device
16 * if specified or truncated size is 0 the part is skipped
17 * <offset> := standard linux memsize
18 * if omitted the part will immediately follow the previous part
19 * or 0 if the first part
20 * <name> := '(' NAME ')'
21 * NAME will appear in /proc/mtd
22 *
23 * <size> and <offset> can be specified such that the parts are out of order
24 * in physical memory and may even overlap.
25 *
26 * The parts are assigned MTD numbers in the order they are specified in the
27 * command line regardless of their order in physical memory.
28 *
29 * Examples:
30 *
31 * 1 NOR Flash, with 1 single writable partition:
32 * edb7312-nor:-
33 *
34 * 1 NOR Flash with 2 partitions, 1 NAND with one
35 * edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
36 */
37
38 #define pr_fmt(fmt) "mtd: " fmt
39
40 #include <linux/kernel.h>
41 #include <linux/slab.h>
42 #include <linux/mtd/mtd.h>
43 #include <linux/mtd/partitions.h>
44 #include <linux/module.h>
45 #include <linux/err.h>
46
47 /* debug macro */
48 #if 0
49 #define dbg(x) do { printk("DEBUG-CMDLINE-PART: "); printk x; } while(0)
50 #else
51 #define dbg(x)
52 #endif
53
54
55 /* special size referring to all the remaining space in a partition */
56 #define SIZE_REMAINING ULLONG_MAX
57 #define OFFSET_CONTINUOUS ULLONG_MAX
58
59 struct cmdline_mtd_partition {
60 struct cmdline_mtd_partition *next;
61 char *mtd_id;
62 int num_parts;
63 struct mtd_partition *parts;
64 };
65
66 /* mtdpart_setup() parses into here */
67 static struct cmdline_mtd_partition *partitions;
68
69 /* the command line passed to mtdpart_setup() */
70 static char *mtdparts;
71 static char *cmdline;
72 static int cmdline_parsed;
73
74 /*
75 * Parse one partition definition for an MTD. Since there can be many
76 * comma separated partition definitions, this function calls itself
77 * recursively until no more partition definitions are found. Nice side
78 * effect: the memory to keep the mtd_partition structs and the names
79 * is allocated upon the last definition being found. At that point the
80 * syntax has been verified ok.
81 */
82 static struct mtd_partition * newpart(char *s,
83 char **retptr,
84 int *num_parts,
85 int this_part,
86 unsigned char **extra_mem_ptr,
87 int extra_mem_size)
88 {
89 struct mtd_partition *parts;
90 unsigned long long size, offset = OFFSET_CONTINUOUS;
91 char *name;
92 int name_len;
93 unsigned char *extra_mem;
94 char delim;
95 unsigned int mask_flags;
96
97 /* fetch the partition size */
98 if (*s == '-') {
99 /* assign all remaining space to this partition */
100 size = SIZE_REMAINING;
101 s++;
102 } else {
103 size = memparse(s, &s);
104 if (!size) {
105 pr_err("partition has size 0\n");
106 return ERR_PTR(-EINVAL);
107 }
108 }
109
110 /* fetch partition name and flags */
111 mask_flags = 0; /* this is going to be a regular partition */
112 delim = 0;
113
114 /* check for offset */
115 if (*s == '@') {
116 s++;
117 offset = memparse(s, &s);
118 }
119
120 /* now look for name */
121 if (*s == '(')
122 delim = ')';
123
124 if (delim) {
125 char *p;
126
127 name = ++s;
128 p = strchr(name, delim);
129 if (!p) {
130 pr_err("no closing %c found in partition name\n", delim);
131 return ERR_PTR(-EINVAL);
132 }
133 name_len = p - name;
134 s = p + 1;
135 } else {
136 name = NULL;
137 name_len = 13; /* Partition_000 */
138 }
139
140 /* record name length for memory allocation later */
141 extra_mem_size += name_len + 1;
142
143 /* test for options */
144 if (strncmp(s, "ro", 2) == 0) {
145 mask_flags |= MTD_WRITEABLE;
146 s += 2;
147 }
148
149 /* if lk is found do NOT unlock the MTD partition*/
150 if (strncmp(s, "lk", 2) == 0) {
151 mask_flags |= MTD_POWERUP_LOCK;
152 s += 2;
153 }
154
155 /* test if more partitions are following */
156 if (*s == ',') {
157 if (size == SIZE_REMAINING) {
158 pr_err("no partitions allowed after a fill-up partition\n");
159 return ERR_PTR(-EINVAL);
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 (IS_ERR(parts))
165 return parts;
166 } else {
167 /* this is the last partition: allocate space for all */
168 int alloc_size;
169
170 *num_parts = this_part + 1;
171 alloc_size = *num_parts * sizeof(struct mtd_partition) +
172 extra_mem_size;
173
174 parts = kzalloc(alloc_size, GFP_KERNEL);
175 if (!parts)
176 return ERR_PTR(-ENOMEM);
177 extra_mem = (unsigned char *)(parts + *num_parts);
178 }
179
180 /*
181 * enter this partition (offset will be calculated later if it is
182 * OFFSET_CONTINUOUS at this point)
183 */
184 parts[this_part].size = size;
185 parts[this_part].offset = offset;
186 parts[this_part].mask_flags = mask_flags;
187 if (name)
188 strlcpy(extra_mem, name, name_len + 1);
189 else
190 sprintf(extra_mem, "Partition_%03d", this_part);
191 parts[this_part].name = extra_mem;
192 extra_mem += name_len + 1;
193
194 dbg(("partition %d: name <%s>, offset %llx, size %llx, mask flags %x\n",
195 this_part, parts[this_part].name, parts[this_part].offset,
196 parts[this_part].size, parts[this_part].mask_flags));
197
198 /* return (updated) pointer to extra_mem memory */
199 if (extra_mem_ptr)
200 *extra_mem_ptr = extra_mem;
201
202 /* return (updated) pointer command line string */
203 *retptr = s;
204
205 /* return partition table */
206 return parts;
207 }
208
209 /*
210 * Parse the command line.
211 */
212 static int mtdpart_setup_real(char *s)
213 {
214 cmdline_parsed = 1;
215
216 for( ; s != NULL; )
217 {
218 struct cmdline_mtd_partition *this_mtd;
219 struct mtd_partition *parts;
220 int mtd_id_len, num_parts;
221 char *p, *mtd_id;
222
223 mtd_id = s;
224
225 /* fetch <mtd-id> */
226 p = strchr(s, ':');
227 if (!p) {
228 pr_err("no mtd-id\n");
229 return -EINVAL;
230 }
231 mtd_id_len = p - mtd_id;
232
233 dbg(("parsing <%s>\n", p+1));
234
235 /*
236 * parse one mtd. have it reserve memory for the
237 * struct cmdline_mtd_partition and the mtd-id string.
238 */
239 parts = newpart(p + 1, /* cmdline */
240 &s, /* out: updated cmdline ptr */
241 &num_parts, /* out: number of parts */
242 0, /* first partition */
243 (unsigned char**)&this_mtd, /* out: extra mem */
244 mtd_id_len + 1 + sizeof(*this_mtd) +
245 sizeof(void*)-1 /*alignment*/);
246 if (IS_ERR(parts)) {
247 /*
248 * An error occurred. We're either:
249 * a) out of memory, or
250 * b) in the middle of the partition spec
251 * Either way, this mtd is hosed and we're
252 * unlikely to succeed in parsing any more
253 */
254 return PTR_ERR(parts);
255 }
256
257 /* align this_mtd */
258 this_mtd = (struct cmdline_mtd_partition *)
259 ALIGN((unsigned long)this_mtd, sizeof(void *));
260 /* enter results */
261 this_mtd->parts = parts;
262 this_mtd->num_parts = num_parts;
263 this_mtd->mtd_id = (char*)(this_mtd + 1);
264 strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
265
266 /* link into chain */
267 this_mtd->next = partitions;
268 partitions = this_mtd;
269
270 dbg(("mtdid=<%s> num_parts=<%d>\n",
271 this_mtd->mtd_id, this_mtd->num_parts));
272
273
274 /* EOS - we're done */
275 if (*s == 0)
276 break;
277
278 /* does another spec follow? */
279 if (*s != ';') {
280 pr_err("bad character after partition (%c)\n", *s);
281 return -EINVAL;
282 }
283 s++;
284 }
285
286 return 0;
287 }
288
289 /*
290 * Main function to be called from the MTD mapping driver/device to
291 * obtain the partitioning information. At this point the command line
292 * arguments will actually be parsed and turned to struct mtd_partition
293 * information. It returns partitions for the requested mtd device, or
294 * the first one in the chain if a NULL mtd_id is passed in.
295 */
296 static int parse_cmdline_partitions(struct mtd_info *master,
297 const struct mtd_partition **pparts,
298 struct mtd_part_parser_data *data)
299 {
300 unsigned long long offset;
301 int i, err;
302 struct cmdline_mtd_partition *part;
303 const char *mtd_id = master->name;
304
305 /* parse command line */
306 if (!cmdline_parsed) {
307 err = mtdpart_setup_real(cmdline);
308 if (err)
309 return err;
310 }
311
312 /*
313 * Search for the partition definition matching master->name.
314 * If master->name is not set, stop at first partition definition.
315 */
316 for (part = partitions; part; part = part->next) {
317 if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
318 break;
319 }
320
321 if (!part)
322 return 0;
323
324 for (i = 0, offset = 0; i < part->num_parts; i++) {
325 if (part->parts[i].offset == OFFSET_CONTINUOUS)
326 part->parts[i].offset = offset;
327 else
328 offset = part->parts[i].offset;
329
330 if (part->parts[i].size == SIZE_REMAINING)
331 part->parts[i].size = master->size - offset;
332
333 if (offset + part->parts[i].size > master->size) {
334 pr_warn("%s: partitioning exceeds flash size, truncating\n",
335 part->mtd_id);
336 part->parts[i].size = master->size - offset;
337 }
338 offset += part->parts[i].size;
339
340 if (part->parts[i].size == 0) {
341 pr_warn("%s: skipping zero sized partition\n",
342 part->mtd_id);
343 part->num_parts--;
344 memmove(&part->parts[i], &part->parts[i + 1],
345 sizeof(*part->parts) * (part->num_parts - i));
346 i--;
347 }
348 }
349
350 *pparts = kmemdup(part->parts, sizeof(*part->parts) * part->num_parts,
351 GFP_KERNEL);
352 if (!*pparts)
353 return -ENOMEM;
354
355 return part->num_parts;
356 }
357
358
359 /*
360 * This is the handler for our kernel parameter, called from
361 * main.c::checksetup(). Note that we can not yet kmalloc() anything,
362 * so we only save the commandline for later processing.
363 *
364 * This function needs to be visible for bootloaders.
365 */
366 static int __init mtdpart_setup(char *s)
367 {
368 cmdline = s;
369 return 1;
370 }
371
372 __setup("mtdparts=", mtdpart_setup);
373
374 static struct mtd_part_parser cmdline_parser = {
375 .parse_fn = parse_cmdline_partitions,
376 .name = "cmdlinepart",
377 };
378
379 static int __init cmdline_parser_init(void)
380 {
381 if (mtdparts)
382 mtdpart_setup(mtdparts);
383 register_mtd_parser(&cmdline_parser);
384 return 0;
385 }
386
387 static void __exit cmdline_parser_exit(void)
388 {
389 deregister_mtd_parser(&cmdline_parser);
390 }
391
392 module_init(cmdline_parser_init);
393 module_exit(cmdline_parser_exit);
394
395 MODULE_PARM_DESC(mtdparts, "Partitioning specification");
396 module_param(mtdparts, charp, 0);
397
398 MODULE_LICENSE("GPL");
399 MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
400 MODULE_DESCRIPTION("Command line configuration of MTD partitions");