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][slc]
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 */
newpart(char * s,char ** retptr,int * num_parts,int this_part,unsigned char ** extra_mem_ptr,int extra_mem_size)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, add_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 add_flags = 0;
113 delim = 0;
114
115 /* check for offset */
116 if (*s == '@') {
117 s++;
118 offset = memparse(s, &s);
119 }
120
121 /* now look for name */
122 if (*s == '(')
123 delim = ')';
124
125 if (delim) {
126 char *p;
127
128 name = ++s;
129 p = strchr(name, delim);
130 if (!p) {
131 pr_err("no closing %c found in partition name\n", delim);
132 return ERR_PTR(-EINVAL);
133 }
134 name_len = p - name;
135 s = p + 1;
136 } else {
137 name = NULL;
138 name_len = 13; /* Partition_000 */
139 }
140
141 /* record name length for memory allocation later */
142 extra_mem_size += name_len + 1;
143
144 /* test for options */
145 if (strncmp(s, "ro", 2) == 0) {
146 mask_flags |= MTD_WRITEABLE;
147 s += 2;
148 }
149
150 /* if lk is found do NOT unlock the MTD partition*/
151 if (strncmp(s, "lk", 2) == 0) {
152 mask_flags |= MTD_POWERUP_LOCK;
153 s += 2;
154 }
155
156 /* if slc is found use emulated SLC mode on this partition*/
157 if (!strncmp(s, "slc", 3)) {
158 add_flags |= MTD_SLC_ON_MLC_EMULATION;
159 s += 3;
160 }
161
162 /* test if more partitions are following */
163 if (*s == ',') {
164 if (size == SIZE_REMAINING) {
165 pr_err("no partitions allowed after a fill-up partition\n");
166 return ERR_PTR(-EINVAL);
167 }
168 /* more partitions follow, parse them */
169 parts = newpart(s + 1, &s, num_parts, this_part + 1,
170 &extra_mem, extra_mem_size);
171 if (IS_ERR(parts))
172 return parts;
173 } else {
174 /* this is the last partition: allocate space for all */
175 int alloc_size;
176
177 *num_parts = this_part + 1;
178 alloc_size = *num_parts * sizeof(struct mtd_partition) +
179 extra_mem_size;
180
181 parts = kzalloc(alloc_size, GFP_KERNEL);
182 if (!parts)
183 return ERR_PTR(-ENOMEM);
184 extra_mem = (unsigned char *)(parts + *num_parts);
185 }
186
187 /*
188 * enter this partition (offset will be calculated later if it is
189 * OFFSET_CONTINUOUS at this point)
190 */
191 parts[this_part].size = size;
192 parts[this_part].offset = offset;
193 parts[this_part].mask_flags = mask_flags;
194 parts[this_part].add_flags = add_flags;
195 if (name)
196 strscpy(extra_mem, name, name_len + 1);
197 else
198 sprintf(extra_mem, "Partition_%03d", this_part);
199 parts[this_part].name = extra_mem;
200 extra_mem += name_len + 1;
201
202 dbg(("partition %d: name <%s>, offset %llx, size %llx, mask flags %x\n",
203 this_part, parts[this_part].name, parts[this_part].offset,
204 parts[this_part].size, parts[this_part].mask_flags));
205
206 /* return (updated) pointer to extra_mem memory */
207 if (extra_mem_ptr)
208 *extra_mem_ptr = extra_mem;
209
210 /* return (updated) pointer command line string */
211 *retptr = s;
212
213 /* return partition table */
214 return parts;
215 }
216
217 /*
218 * Parse the command line.
219 */
mtdpart_setup_real(char * s)220 static int mtdpart_setup_real(char *s)
221 {
222 cmdline_parsed = 1;
223
224 for( ; s != NULL; )
225 {
226 struct cmdline_mtd_partition *this_mtd;
227 struct mtd_partition *parts;
228 int mtd_id_len, num_parts;
229 char *p, *mtd_id, *semicol, *open_parenth;
230
231 /*
232 * Replace the first ';' by a NULL char so strrchr can work
233 * properly.
234 */
235 semicol = strchr(s, ';');
236 if (semicol)
237 *semicol = '\0';
238
239 /*
240 * make sure that part-names with ":" will not be handled as
241 * part of the mtd-id with an ":"
242 */
243 open_parenth = strchr(s, '(');
244 if (open_parenth)
245 *open_parenth = '\0';
246
247 mtd_id = s;
248
249 /*
250 * fetch <mtd-id>. We use strrchr to ignore all ':' that could
251 * be present in the MTD name, only the last one is interpreted
252 * as an <mtd-id>/<part-definition> separator.
253 */
254 p = strrchr(s, ':');
255
256 /* Restore the '(' now. */
257 if (open_parenth)
258 *open_parenth = '(';
259
260 /* Restore the ';' now. */
261 if (semicol)
262 *semicol = ';';
263
264 if (!p) {
265 pr_err("no mtd-id\n");
266 return -EINVAL;
267 }
268 mtd_id_len = p - mtd_id;
269
270 dbg(("parsing <%s>\n", p+1));
271
272 /*
273 * parse one mtd. have it reserve memory for the
274 * struct cmdline_mtd_partition and the mtd-id string.
275 */
276 parts = newpart(p + 1, /* cmdline */
277 &s, /* out: updated cmdline ptr */
278 &num_parts, /* out: number of parts */
279 0, /* first partition */
280 (unsigned char**)&this_mtd, /* out: extra mem */
281 mtd_id_len + 1 + sizeof(*this_mtd) +
282 sizeof(void*)-1 /*alignment*/);
283 if (IS_ERR(parts)) {
284 /*
285 * An error occurred. We're either:
286 * a) out of memory, or
287 * b) in the middle of the partition spec
288 * Either way, this mtd is hosed and we're
289 * unlikely to succeed in parsing any more
290 */
291 return PTR_ERR(parts);
292 }
293
294 /* align this_mtd */
295 this_mtd = (struct cmdline_mtd_partition *)
296 ALIGN((unsigned long)this_mtd, sizeof(void *));
297 /* enter results */
298 this_mtd->parts = parts;
299 this_mtd->num_parts = num_parts;
300 this_mtd->mtd_id = (char*)(this_mtd + 1);
301 strscpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
302
303 /* link into chain */
304 this_mtd->next = partitions;
305 partitions = this_mtd;
306
307 dbg(("mtdid=<%s> num_parts=<%d>\n",
308 this_mtd->mtd_id, this_mtd->num_parts));
309
310
311 /* EOS - we're done */
312 if (*s == 0)
313 break;
314
315 /* does another spec follow? */
316 if (*s != ';') {
317 pr_err("bad character after partition (%c)\n", *s);
318 return -EINVAL;
319 }
320 s++;
321 }
322
323 return 0;
324 }
325
326 /*
327 * Main function to be called from the MTD mapping driver/device to
328 * obtain the partitioning information. At this point the command line
329 * arguments will actually be parsed and turned to struct mtd_partition
330 * information. It returns partitions for the requested mtd device, or
331 * the first one in the chain if a NULL mtd_id is passed in.
332 */
parse_cmdline_partitions(struct mtd_info * master,const struct mtd_partition ** pparts,struct mtd_part_parser_data * data)333 static int parse_cmdline_partitions(struct mtd_info *master,
334 const struct mtd_partition **pparts,
335 struct mtd_part_parser_data *data)
336 {
337 unsigned long long offset;
338 int i, err;
339 struct cmdline_mtd_partition *part;
340 const char *mtd_id = master->name;
341
342 /* parse command line */
343 if (!cmdline_parsed) {
344 err = mtdpart_setup_real(cmdline);
345 if (err)
346 return err;
347 }
348
349 /*
350 * Search for the partition definition matching master->name.
351 * If master->name is not set, stop at first partition definition.
352 */
353 for (part = partitions; part; part = part->next) {
354 if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
355 break;
356 }
357
358 if (!part)
359 return 0;
360
361 for (i = 0, offset = 0; i < part->num_parts; i++) {
362 if (part->parts[i].offset == OFFSET_CONTINUOUS)
363 part->parts[i].offset = offset;
364 else
365 offset = part->parts[i].offset;
366
367 if (part->parts[i].size == SIZE_REMAINING)
368 part->parts[i].size = master->size - offset;
369
370 if (offset + part->parts[i].size > master->size) {
371 pr_warn("%s: partitioning exceeds flash size, truncating\n",
372 part->mtd_id);
373 part->parts[i].size = master->size - offset;
374 }
375 offset += part->parts[i].size;
376
377 if (part->parts[i].size == 0) {
378 pr_warn("%s: skipping zero sized partition\n",
379 part->mtd_id);
380 part->num_parts--;
381 memmove(&part->parts[i], &part->parts[i + 1],
382 sizeof(*part->parts) * (part->num_parts - i));
383 i--;
384 }
385 }
386
387 *pparts = kmemdup(part->parts, sizeof(*part->parts) * part->num_parts,
388 GFP_KERNEL);
389 if (!*pparts)
390 return -ENOMEM;
391
392 return part->num_parts;
393 }
394
395
396 /*
397 * This is the handler for our kernel parameter, called from
398 * main.c::checksetup(). Note that we can not yet kmalloc() anything,
399 * so we only save the commandline for later processing.
400 *
401 * This function needs to be visible for bootloaders.
402 */
mtdpart_setup(char * s)403 static int __init mtdpart_setup(char *s)
404 {
405 cmdline = s;
406 return 1;
407 }
408
409 __setup("mtdparts=", mtdpart_setup);
410
411 static struct mtd_part_parser cmdline_parser = {
412 .parse_fn = parse_cmdline_partitions,
413 .name = "cmdlinepart",
414 };
415
cmdline_parser_init(void)416 static int __init cmdline_parser_init(void)
417 {
418 if (mtdparts)
419 mtdpart_setup(mtdparts);
420 register_mtd_parser(&cmdline_parser);
421 return 0;
422 }
423
cmdline_parser_exit(void)424 static void __exit cmdline_parser_exit(void)
425 {
426 deregister_mtd_parser(&cmdline_parser);
427 }
428
429 module_init(cmdline_parser_init);
430 module_exit(cmdline_parser_exit);
431
432 MODULE_PARM_DESC(mtdparts, "Partitioning specification");
433 module_param(mtdparts, charp, 0);
434
435 MODULE_LICENSE("GPL");
436 MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
437 MODULE_DESCRIPTION("Command line configuration of MTD partitions");
438