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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/* special size referring to all the remaining space in a partition */
48#define SIZE_REMAINING ULLONG_MAX
49#define OFFSET_CONTINUOUS ULLONG_MAX
50
51struct cmdline_mtd_partition {
52 struct cmdline_mtd_partition *next;
53 char *mtd_id;
54 int num_parts;
55 struct mtd_partition *parts;
56};
57
58/* mtdpart_setup() parses into here */
59static struct cmdline_mtd_partition *partitions;
60
61/* the command line passed to mtdpart_setup() */
62static char *mtdparts;
63static char *cmdline;
64static int cmdline_parsed;
65
66/*
67 * Parse one partition definition for an MTD. Since there can be many
68 * comma separated partition definitions, this function calls itself
69 * recursively until no more partition definitions are found. Nice side
70 * effect: the memory to keep the mtd_partition structs and the names
71 * is allocated upon the last definition being found. At that point the
72 * syntax has been verified ok.
73 */
74static struct mtd_partition * newpart(char *s,
75 char **retptr,
76 int *num_parts,
77 int this_part,
78 unsigned char **extra_mem_ptr,
79 int extra_mem_size)
80{
81 struct mtd_partition *parts;
82 unsigned long long size, offset = OFFSET_CONTINUOUS;
83 char *name;
84 int name_len;
85 unsigned char *extra_mem;
86 char delim;
87 unsigned int mask_flags, add_flags;
88
89 /* fetch the partition size */
90 if (*s == '-') {
91 /* assign all remaining space to this partition */
92 size = SIZE_REMAINING;
93 s++;
94 } else {
95 size = memparse(s, &s);
96 if (!size) {
97 pr_err("partition has size 0\n");
98 return ERR_PTR(-EINVAL);
99 }
100 }
101
102 /* fetch partition name and flags */
103 mask_flags = 0; /* this is going to be a regular partition */
104 add_flags = 0;
105 delim = 0;
106
107 /* check for offset */
108 if (*s == '@') {
109 s++;
110 offset = memparse(s, &s);
111 }
112
113 /* now look for name */
114 if (*s == '(')
115 delim = ')';
116
117 if (delim) {
118 char *p;
119
120 name = ++s;
121 p = strchr(name, delim);
122 if (!p) {
123 pr_err("no closing %c found in partition name\n", delim);
124 return ERR_PTR(-EINVAL);
125 }
126 name_len = p - name;
127 s = p + 1;
128 } else {
129 name = NULL;
130 name_len = 13; /* Partition_000 */
131 }
132
133 /* record name length for memory allocation later */
134 extra_mem_size += name_len + 1;
135
136 /* test for options */
137 if (strncmp(s, "ro", 2) == 0) {
138 mask_flags |= MTD_WRITEABLE;
139 s += 2;
140 }
141
142 /* if lk is found do NOT unlock the MTD partition*/
143 if (strncmp(s, "lk", 2) == 0) {
144 mask_flags |= MTD_POWERUP_LOCK;
145 s += 2;
146 }
147
148 /* if slc is found use emulated SLC mode on this partition*/
149 if (!strncmp(s, "slc", 3)) {
150 add_flags |= MTD_SLC_ON_MLC_EMULATION;
151 s += 3;
152 }
153
154 /* test if more partitions are following */
155 if (*s == ',') {
156 if (size == SIZE_REMAINING) {
157 pr_err("no partitions allowed after a fill-up partition\n");
158 return ERR_PTR(-EINVAL);
159 }
160 /* more partitions follow, parse them */
161 parts = newpart(s + 1, &s, num_parts, this_part + 1,
162 &extra_mem, extra_mem_size);
163 if (IS_ERR(parts))
164 return parts;
165 } else {
166 /* this is the last partition: allocate space for all */
167 int alloc_size;
168
169 *num_parts = this_part + 1;
170 alloc_size = *num_parts * sizeof(struct mtd_partition) +
171 extra_mem_size;
172
173 parts = kzalloc(alloc_size, GFP_KERNEL);
174 if (!parts)
175 return ERR_PTR(-ENOMEM);
176 extra_mem = (unsigned char *)(parts + *num_parts);
177 }
178
179 /*
180 * enter this partition (offset will be calculated later if it is
181 * OFFSET_CONTINUOUS at this point)
182 */
183 parts[this_part].size = size;
184 parts[this_part].offset = offset;
185 parts[this_part].mask_flags = mask_flags;
186 parts[this_part].add_flags = add_flags;
187 if (name)
188 strscpy(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 pr_debug("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 */
212static 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, *semicol, *open_parenth;
222
223 /*
224 * Replace the first ';' by a NULL char so strrchr can work
225 * properly.
226 */
227 semicol = strchr(s, ';');
228 if (semicol)
229 *semicol = '\0';
230
231 /*
232 * make sure that part-names with ":" will not be handled as
233 * part of the mtd-id with an ":"
234 */
235 open_parenth = strchr(s, '(');
236 if (open_parenth)
237 *open_parenth = '\0';
238
239 mtd_id = s;
240
241 /*
242 * fetch <mtd-id>. We use strrchr to ignore all ':' that could
243 * be present in the MTD name, only the last one is interpreted
244 * as an <mtd-id>/<part-definition> separator.
245 */
246 p = strrchr(s, ':');
247
248 /* Restore the '(' now. */
249 if (open_parenth)
250 *open_parenth = '(';
251
252 /* Restore the ';' now. */
253 if (semicol)
254 *semicol = ';';
255
256 if (!p) {
257 pr_err("no mtd-id\n");
258 return -EINVAL;
259 }
260 mtd_id_len = p - mtd_id;
261
262 pr_debug("parsing <%s>\n", p+1);
263
264 /*
265 * parse one mtd. have it reserve memory for the
266 * struct cmdline_mtd_partition and the mtd-id string.
267 */
268 parts = newpart(p + 1, /* cmdline */
269 &s, /* out: updated cmdline ptr */
270 &num_parts, /* out: number of parts */
271 0, /* first partition */
272 (unsigned char**)&this_mtd, /* out: extra mem */
273 mtd_id_len + 1 + sizeof(*this_mtd) +
274 sizeof(void*)-1 /*alignment*/);
275 if (IS_ERR(parts)) {
276 /*
277 * An error occurred. We're either:
278 * a) out of memory, or
279 * b) in the middle of the partition spec
280 * Either way, this mtd is hosed and we're
281 * unlikely to succeed in parsing any more
282 */
283 return PTR_ERR(parts);
284 }
285
286 /* align this_mtd */
287 this_mtd = (struct cmdline_mtd_partition *)
288 ALIGN((unsigned long)this_mtd, sizeof(void *));
289 /* enter results */
290 this_mtd->parts = parts;
291 this_mtd->num_parts = num_parts;
292 this_mtd->mtd_id = (char*)(this_mtd + 1);
293 strscpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
294
295 /* link into chain */
296 this_mtd->next = partitions;
297 partitions = this_mtd;
298
299 pr_debug("mtdid=<%s> num_parts=<%d>\n",
300 this_mtd->mtd_id, this_mtd->num_parts);
301
302
303 /* EOS - we're done */
304 if (*s == 0)
305 break;
306
307 /* does another spec follow? */
308 if (*s != ';') {
309 pr_err("bad character after partition (%c)\n", *s);
310 return -EINVAL;
311 }
312 s++;
313 }
314
315 return 0;
316}
317
318/*
319 * Main function to be called from the MTD mapping driver/device to
320 * obtain the partitioning information. At this point the command line
321 * arguments will actually be parsed and turned to struct mtd_partition
322 * information. It returns partitions for the requested mtd device, or
323 * the first one in the chain if a NULL mtd_id is passed in.
324 */
325static int parse_cmdline_partitions(struct mtd_info *master,
326 const struct mtd_partition **pparts,
327 struct mtd_part_parser_data *data)
328{
329 unsigned long long offset;
330 int i, err;
331 struct cmdline_mtd_partition *part;
332 const char *mtd_id = master->name;
333
334 /* parse command line */
335 if (!cmdline_parsed) {
336 err = mtdpart_setup_real(cmdline);
337 if (err)
338 return err;
339 }
340
341 /*
342 * Search for the partition definition matching master->name.
343 * If master->name is not set, stop at first partition definition.
344 */
345 for (part = partitions; part; part = part->next) {
346 if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
347 break;
348 }
349
350 if (!part)
351 return 0;
352
353 for (i = 0, offset = 0; i < part->num_parts; i++) {
354 if (part->parts[i].offset == OFFSET_CONTINUOUS)
355 part->parts[i].offset = offset;
356 else
357 offset = part->parts[i].offset;
358
359 if (part->parts[i].size == SIZE_REMAINING)
360 part->parts[i].size = master->size - offset;
361
362 if (offset + part->parts[i].size > master->size) {
363 pr_warn("%s: partitioning exceeds flash size, truncating\n",
364 part->mtd_id);
365 part->parts[i].size = master->size - offset;
366 }
367 offset += part->parts[i].size;
368
369 if (part->parts[i].size == 0) {
370 pr_warn("%s: skipping zero sized partition\n",
371 part->mtd_id);
372 part->num_parts--;
373 memmove(&part->parts[i], &part->parts[i + 1],
374 sizeof(*part->parts) * (part->num_parts - i));
375 i--;
376 }
377 }
378
379 *pparts = kmemdup(part->parts, sizeof(*part->parts) * part->num_parts,
380 GFP_KERNEL);
381 if (!*pparts)
382 return -ENOMEM;
383
384 return part->num_parts;
385}
386
387
388/*
389 * This is the handler for our kernel parameter, called from
390 * main.c::checksetup(). Note that we can not yet kmalloc() anything,
391 * so we only save the commandline for later processing.
392 *
393 * This function needs to be visible for bootloaders.
394 */
395static int __init mtdpart_setup(char *s)
396{
397 cmdline = s;
398 return 1;
399}
400
401__setup("mtdparts=", mtdpart_setup);
402
403static struct mtd_part_parser cmdline_parser = {
404 .parse_fn = parse_cmdline_partitions,
405 .name = "cmdlinepart",
406};
407
408static int __init cmdline_parser_init(void)
409{
410 if (mtdparts)
411 mtdpart_setup(mtdparts);
412 register_mtd_parser(&cmdline_parser);
413 return 0;
414}
415
416static void __exit cmdline_parser_exit(void)
417{
418 deregister_mtd_parser(&cmdline_parser);
419}
420
421module_init(cmdline_parser_init);
422module_exit(cmdline_parser_exit);
423
424MODULE_PARM_DESC(mtdparts, "Partitioning specification");
425module_param(mtdparts, charp, 0);
426
427MODULE_LICENSE("GPL");
428MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
429MODULE_DESCRIPTION("Command line configuration of MTD partitions");