1/*
2 * Read flash partition table from command line
3 *
4 * Copyright © 2002      SYSGO Real-Time Solutions GmbH
5 * Copyright © 2002-2010 David Woodhouse <dwmw2@infradead.org>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
20 *
21 * The format for the command line is as follows:
22 *
23 * mtdparts=<mtddef>[;<mtddef]
24 * <mtddef>  := <mtd-id>:<partdef>[,<partdef>]
25 * <partdef> := <size>[@<offset>][<name>][ro][lk]
26 * <mtd-id>  := unique name used in mapping driver/device (mtd->name)
27 * <size>    := standard linux memsize OR "-" to denote all remaining space
28 *              size is automatically truncated at end of device
29 *              if specified or truncated size is 0 the part is skipped
30 * <offset>  := standard linux memsize
31 *              if omitted the part will immediately follow the previous part
32 *              or 0 if the first part
33 * <name>    := '(' NAME ')'
34 *              NAME will appear in /proc/mtd
35 *
36 * <size> and <offset> can be specified such that the parts are out of order
37 * in physical memory and may even overlap.
38 *
39 * The parts are assigned MTD numbers in the order they are specified in the
40 * command line regardless of their order in physical memory.
41 *
42 * Examples:
43 *
44 * 1 NOR Flash, with 1 single writable partition:
45 * edb7312-nor:-
46 *
47 * 1 NOR Flash with 2 partitions, 1 NAND with one
48 * edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
49 */
50
51#include <linux/kernel.h>
52#include <linux/slab.h>
53#include <linux/mtd/mtd.h>
54#include <linux/mtd/partitions.h>
55#include <linux/module.h>
56#include <linux/err.h>
57
58/* error message prefix */
59#define ERRP "mtd: "
60
61/* debug macro */
62#if 0
63#define dbg(x) do { printk("DEBUG-CMDLINE-PART: "); printk x; } while(0)
64#else
65#define dbg(x)
66#endif
67
68
69/* special size referring to all the remaining space in a partition */
70#define SIZE_REMAINING ULLONG_MAX
71#define OFFSET_CONTINUOUS ULLONG_MAX
72
73struct cmdline_mtd_partition {
74	struct cmdline_mtd_partition *next;
75	char *mtd_id;
76	int num_parts;
77	struct mtd_partition *parts;
78};
79
80/* mtdpart_setup() parses into here */
81static struct cmdline_mtd_partition *partitions;
82
83/* the command line passed to mtdpart_setup() */
84static char *mtdparts;
85static char *cmdline;
86static int cmdline_parsed;
87
88/*
89 * Parse one partition definition for an MTD. Since there can be many
90 * comma separated partition definitions, this function calls itself
91 * recursively until no more partition definitions are found. Nice side
92 * effect: the memory to keep the mtd_partition structs and the names
93 * is allocated upon the last definition being found. At that point the
94 * syntax has been verified ok.
95 */
96static struct mtd_partition * newpart(char *s,
97				      char **retptr,
98				      int *num_parts,
99				      int this_part,
100				      unsigned char **extra_mem_ptr,
101				      int extra_mem_size)
102{
103	struct mtd_partition *parts;
104	unsigned long long size, offset = OFFSET_CONTINUOUS;
105	char *name;
106	int name_len;
107	unsigned char *extra_mem;
108	char delim;
109	unsigned int mask_flags;
110
111	/* fetch the partition size */
112	if (*s == '-') {
113		/* assign all remaining space to this partition */
114		size = SIZE_REMAINING;
115		s++;
116	} else {
117		size = memparse(s, &s);
118		if (size < PAGE_SIZE) {
119			printk(KERN_ERR ERRP "partition size too small (%llx)\n",
120			       size);
121			return ERR_PTR(-EINVAL);
122		}
123	}
124
125	/* fetch partition name and flags */
126	mask_flags = 0; /* this is going to be a regular partition */
127	delim = 0;
128
129	/* check for offset */
130	if (*s == '@') {
131		s++;
132		offset = memparse(s, &s);
133	}
134
135	/* now look for name */
136	if (*s == '(')
137		delim = ')';
138
139	if (delim) {
140		char *p;
141
142		name = ++s;
143		p = strchr(name, delim);
144		if (!p) {
145			printk(KERN_ERR ERRP "no closing %c found in partition name\n", delim);
146			return ERR_PTR(-EINVAL);
147		}
148		name_len = p - name;
149		s = p + 1;
150	} else {
151		name = NULL;
152		name_len = 13; /* Partition_000 */
153	}
154
155	/* record name length for memory allocation later */
156	extra_mem_size += name_len + 1;
157
158	/* test for options */
159	if (strncmp(s, "ro", 2) == 0) {
160		mask_flags |= MTD_WRITEABLE;
161		s += 2;
162	}
163
164	/* if lk is found do NOT unlock the MTD partition*/
165	if (strncmp(s, "lk", 2) == 0) {
166		mask_flags |= MTD_POWERUP_LOCK;
167		s += 2;
168	}
169
170	/* test if more partitions are following */
171	if (*s == ',') {
172		if (size == SIZE_REMAINING) {
173			printk(KERN_ERR ERRP "no partitions allowed after a fill-up partition\n");
174			return ERR_PTR(-EINVAL);
175		}
176		/* more partitions follow, parse them */
177		parts = newpart(s + 1, &s, num_parts, this_part + 1,
178				&extra_mem, extra_mem_size);
179		if (IS_ERR(parts))
180			return parts;
181	} else {
182		/* this is the last partition: allocate space for all */
183		int alloc_size;
184
185		*num_parts = this_part + 1;
186		alloc_size = *num_parts * sizeof(struct mtd_partition) +
187			     extra_mem_size;
188
189		parts = kzalloc(alloc_size, GFP_KERNEL);
190		if (!parts)
191			return ERR_PTR(-ENOMEM);
192		extra_mem = (unsigned char *)(parts + *num_parts);
193	}
194
195	/* enter this partition (offset will be calculated later if it is zero at this point) */
196	parts[this_part].size = size;
197	parts[this_part].offset = offset;
198	parts[this_part].mask_flags = mask_flags;
199	if (name)
200		strlcpy(extra_mem, name, name_len + 1);
201	else
202		sprintf(extra_mem, "Partition_%03d", this_part);
203	parts[this_part].name = extra_mem;
204	extra_mem += name_len + 1;
205
206	dbg(("partition %d: name <%s>, offset %llx, size %llx, mask flags %x\n",
207	     this_part, parts[this_part].name, parts[this_part].offset,
208	     parts[this_part].size, parts[this_part].mask_flags));
209
210	/* return (updated) pointer to extra_mem memory */
211	if (extra_mem_ptr)
212		*extra_mem_ptr = extra_mem;
213
214	/* return (updated) pointer command line string */
215	*retptr = s;
216
217	/* return partition table */
218	return parts;
219}
220
221/*
222 * Parse the command line.
223 */
224static int mtdpart_setup_real(char *s)
225{
226	cmdline_parsed = 1;
227
228	for( ; s != NULL; )
229	{
230		struct cmdline_mtd_partition *this_mtd;
231		struct mtd_partition *parts;
232		int mtd_id_len, num_parts;
233		char *p, *mtd_id;
234
235		mtd_id = s;
236
237		/* fetch <mtd-id> */
238		p = strchr(s, ':');
239		if (!p) {
240			printk(KERN_ERR ERRP "no mtd-id\n");
241			return -EINVAL;
242		}
243		mtd_id_len = p - mtd_id;
244
245		dbg(("parsing <%s>\n", p+1));
246
247		/*
248		 * parse one mtd. have it reserve memory for the
249		 * struct cmdline_mtd_partition and the mtd-id string.
250		 */
251		parts = newpart(p + 1,		/* cmdline */
252				&s,		/* out: updated cmdline ptr */
253				&num_parts,	/* out: number of parts */
254				0,		/* first partition */
255				(unsigned char**)&this_mtd, /* out: extra mem */
256				mtd_id_len + 1 + sizeof(*this_mtd) +
257				sizeof(void*)-1 /*alignment*/);
258		if (IS_ERR(parts)) {
259			/*
260			 * An error occurred. We're either:
261			 * a) out of memory, or
262			 * b) in the middle of the partition spec
263			 * Either way, this mtd is hosed and we're
264			 * unlikely to succeed in parsing any more
265			 */
266			 return PTR_ERR(parts);
267		 }
268
269		/* align this_mtd */
270		this_mtd = (struct cmdline_mtd_partition *)
271				ALIGN((unsigned long)this_mtd, sizeof(void *));
272		/* enter results */
273		this_mtd->parts = parts;
274		this_mtd->num_parts = num_parts;
275		this_mtd->mtd_id = (char*)(this_mtd + 1);
276		strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
277
278		/* link into chain */
279		this_mtd->next = partitions;
280		partitions = this_mtd;
281
282		dbg(("mtdid=<%s> num_parts=<%d>\n",
283		     this_mtd->mtd_id, this_mtd->num_parts));
284
285
286		/* EOS - we're done */
287		if (*s == 0)
288			break;
289
290		/* does another spec follow? */
291		if (*s != ';') {
292			printk(KERN_ERR ERRP "bad character after partition (%c)\n", *s);
293			return -EINVAL;
294		}
295		s++;
296	}
297
298	return 0;
299}
300
301/*
302 * Main function to be called from the MTD mapping driver/device to
303 * obtain the partitioning information. At this point the command line
304 * arguments will actually be parsed and turned to struct mtd_partition
305 * information. It returns partitions for the requested mtd device, or
306 * the first one in the chain if a NULL mtd_id is passed in.
307 */
308static int parse_cmdline_partitions(struct mtd_info *master,
309				    struct mtd_partition **pparts,
310				    struct mtd_part_parser_data *data)
311{
312	unsigned long long offset;
313	int i, err;
314	struct cmdline_mtd_partition *part;
315	const char *mtd_id = master->name;
316
317	/* parse command line */
318	if (!cmdline_parsed) {
319		err = mtdpart_setup_real(cmdline);
320		if (err)
321			return err;
322	}
323
324	/*
325	 * Search for the partition definition matching master->name.
326	 * If master->name is not set, stop at first partition definition.
327	 */
328	for (part = partitions; part; part = part->next) {
329		if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
330			break;
331	}
332
333	if (!part)
334		return 0;
335
336	for (i = 0, offset = 0; i < part->num_parts; i++) {
337		if (part->parts[i].offset == OFFSET_CONTINUOUS)
338			part->parts[i].offset = offset;
339		else
340			offset = part->parts[i].offset;
341
342		if (part->parts[i].size == SIZE_REMAINING)
343			part->parts[i].size = master->size - offset;
344
345		if (offset + part->parts[i].size > master->size) {
346			printk(KERN_WARNING ERRP
347			       "%s: partitioning exceeds flash size, truncating\n",
348			       part->mtd_id);
349			part->parts[i].size = master->size - offset;
350		}
351		offset += part->parts[i].size;
352
353		if (part->parts[i].size == 0) {
354			printk(KERN_WARNING ERRP
355			       "%s: skipping zero sized partition\n",
356			       part->mtd_id);
357			part->num_parts--;
358			memmove(&part->parts[i], &part->parts[i + 1],
359				sizeof(*part->parts) * (part->num_parts - i));
360			i--;
361		}
362	}
363
364	*pparts = kmemdup(part->parts, sizeof(*part->parts) * part->num_parts,
365			  GFP_KERNEL);
366	if (!*pparts)
367		return -ENOMEM;
368
369	return part->num_parts;
370}
371
372
373/*
374 * This is the handler for our kernel parameter, called from
375 * main.c::checksetup(). Note that we can not yet kmalloc() anything,
376 * so we only save the commandline for later processing.
377 *
378 * This function needs to be visible for bootloaders.
379 */
380static int __init mtdpart_setup(char *s)
381{
382	cmdline = s;
383	return 1;
384}
385
386__setup("mtdparts=", mtdpart_setup);
387
388static struct mtd_part_parser cmdline_parser = {
389	.owner = THIS_MODULE,
390	.parse_fn = parse_cmdline_partitions,
391	.name = "cmdlinepart",
392};
393
394static int __init cmdline_parser_init(void)
395{
396	if (mtdparts)
397		mtdpart_setup(mtdparts);
398	register_mtd_parser(&cmdline_parser);
399	return 0;
400}
401
402static void __exit cmdline_parser_exit(void)
403{
404	deregister_mtd_parser(&cmdline_parser);
405}
406
407module_init(cmdline_parser_init);
408module_exit(cmdline_parser_exit);
409
410MODULE_PARM_DESC(mtdparts, "Partitioning specification");
411module_param(mtdparts, charp, 0);
412
413MODULE_LICENSE("GPL");
414MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
415MODULE_DESCRIPTION("Command line configuration of MTD partitions");
416