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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/* 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
59struct 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 */
67static struct cmdline_mtd_partition *partitions;
68
69/* the command line passed to mtdpart_setup() */
70static char *mtdparts;
71static char *cmdline;
72static 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 */
82static 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 strlcpy(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 */
220static 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;
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 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 (semicol)
250 *semicol = ';';
251
252 if (!p) {
253 pr_err("no mtd-id\n");
254 return -EINVAL;
255 }
256 mtd_id_len = p - mtd_id;
257
258 dbg(("parsing <%s>\n", p+1));
259
260 /*
261 * parse one mtd. have it reserve memory for the
262 * struct cmdline_mtd_partition and the mtd-id string.
263 */
264 parts = newpart(p + 1, /* cmdline */
265 &s, /* out: updated cmdline ptr */
266 &num_parts, /* out: number of parts */
267 0, /* first partition */
268 (unsigned char**)&this_mtd, /* out: extra mem */
269 mtd_id_len + 1 + sizeof(*this_mtd) +
270 sizeof(void*)-1 /*alignment*/);
271 if (IS_ERR(parts)) {
272 /*
273 * An error occurred. We're either:
274 * a) out of memory, or
275 * b) in the middle of the partition spec
276 * Either way, this mtd is hosed and we're
277 * unlikely to succeed in parsing any more
278 */
279 return PTR_ERR(parts);
280 }
281
282 /* align this_mtd */
283 this_mtd = (struct cmdline_mtd_partition *)
284 ALIGN((unsigned long)this_mtd, sizeof(void *));
285 /* enter results */
286 this_mtd->parts = parts;
287 this_mtd->num_parts = num_parts;
288 this_mtd->mtd_id = (char*)(this_mtd + 1);
289 strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
290
291 /* link into chain */
292 this_mtd->next = partitions;
293 partitions = this_mtd;
294
295 dbg(("mtdid=<%s> num_parts=<%d>\n",
296 this_mtd->mtd_id, this_mtd->num_parts));
297
298
299 /* EOS - we're done */
300 if (*s == 0)
301 break;
302
303 /* does another spec follow? */
304 if (*s != ';') {
305 pr_err("bad character after partition (%c)\n", *s);
306 return -EINVAL;
307 }
308 s++;
309 }
310
311 return 0;
312}
313
314/*
315 * Main function to be called from the MTD mapping driver/device to
316 * obtain the partitioning information. At this point the command line
317 * arguments will actually be parsed and turned to struct mtd_partition
318 * information. It returns partitions for the requested mtd device, or
319 * the first one in the chain if a NULL mtd_id is passed in.
320 */
321static int parse_cmdline_partitions(struct mtd_info *master,
322 const struct mtd_partition **pparts,
323 struct mtd_part_parser_data *data)
324{
325 unsigned long long offset;
326 int i, err;
327 struct cmdline_mtd_partition *part;
328 const char *mtd_id = master->name;
329
330 /* parse command line */
331 if (!cmdline_parsed) {
332 err = mtdpart_setup_real(cmdline);
333 if (err)
334 return err;
335 }
336
337 /*
338 * Search for the partition definition matching master->name.
339 * If master->name is not set, stop at first partition definition.
340 */
341 for (part = partitions; part; part = part->next) {
342 if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
343 break;
344 }
345
346 if (!part)
347 return 0;
348
349 for (i = 0, offset = 0; i < part->num_parts; i++) {
350 if (part->parts[i].offset == OFFSET_CONTINUOUS)
351 part->parts[i].offset = offset;
352 else
353 offset = part->parts[i].offset;
354
355 if (part->parts[i].size == SIZE_REMAINING)
356 part->parts[i].size = master->size - offset;
357
358 if (offset + part->parts[i].size > master->size) {
359 pr_warn("%s: partitioning exceeds flash size, truncating\n",
360 part->mtd_id);
361 part->parts[i].size = master->size - offset;
362 }
363 offset += part->parts[i].size;
364
365 if (part->parts[i].size == 0) {
366 pr_warn("%s: skipping zero sized partition\n",
367 part->mtd_id);
368 part->num_parts--;
369 memmove(&part->parts[i], &part->parts[i + 1],
370 sizeof(*part->parts) * (part->num_parts - i));
371 i--;
372 }
373 }
374
375 *pparts = kmemdup(part->parts, sizeof(*part->parts) * part->num_parts,
376 GFP_KERNEL);
377 if (!*pparts)
378 return -ENOMEM;
379
380 return part->num_parts;
381}
382
383
384/*
385 * This is the handler for our kernel parameter, called from
386 * main.c::checksetup(). Note that we can not yet kmalloc() anything,
387 * so we only save the commandline for later processing.
388 *
389 * This function needs to be visible for bootloaders.
390 */
391static int __init mtdpart_setup(char *s)
392{
393 cmdline = s;
394 return 1;
395}
396
397__setup("mtdparts=", mtdpart_setup);
398
399static struct mtd_part_parser cmdline_parser = {
400 .parse_fn = parse_cmdline_partitions,
401 .name = "cmdlinepart",
402};
403
404static int __init cmdline_parser_init(void)
405{
406 if (mtdparts)
407 mtdpart_setup(mtdparts);
408 register_mtd_parser(&cmdline_parser);
409 return 0;
410}
411
412static void __exit cmdline_parser_exit(void)
413{
414 deregister_mtd_parser(&cmdline_parser);
415}
416
417module_init(cmdline_parser_init);
418module_exit(cmdline_parser_exit);
419
420MODULE_PARM_DESC(mtdparts, "Partitioning specification");
421module_param(mtdparts, charp, 0);
422
423MODULE_LICENSE("GPL");
424MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
425MODULE_DESCRIPTION("Command line configuration of MTD partitions");