summaryrefslogtreecommitdiffstats
path: root/drivers/mtd/cmdlinepart.c
blob: 3402ce448702bfa897bd9f9e4468c1e5e16b9324 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
/*
 * $Id: cmdlinepart.c,v 1.19 2005/11/07 11:14:19 gleixner Exp $
 *
 * Read flash partition table from command line
 *
 * Copyright 2002 SYSGO Real-Time Solutions GmbH
 *
 * The format for the command line is as follows:
 *
 * mtdparts=<mtddef>[;<mtddef]
 * <mtddef>  := <mtd-id>:<partdef>[,<partdef>]
 * <partdef> := <size>[@offset][<name>][ro]
 * <mtd-id>  := unique name used in mapping driver/device (mtd->name)
 * <size>    := standard linux memsize OR "-" to denote all remaining space
 * <name>    := '(' NAME ')'
 *
 * Examples:
 *
 * 1 NOR Flash, with 1 single writable partition:
 * edb7312-nor:-
 *
 * 1 NOR Flash with 2 partitions, 1 NAND with one
 * edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
 */

#include <linux/kernel.h>
#include <linux/slab.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/bootmem.h>

/* error message prefix */
#define ERRP "mtd: "

/* debug macro */
#if 0
#define dbg(x) do { printk("DEBUG-CMDLINE-PART: "); printk x; } while(0)
#else
#define dbg(x)
#endif


/* special size referring to all the remaining space in a partition */
#define SIZE_REMAINING UINT_MAX
#define OFFSET_CONTINUOUS UINT_MAX

struct cmdline_mtd_partition {
	struct cmdline_mtd_partition *next;
	char *mtd_id;
	int num_parts;
	struct mtd_partition *parts;
};

/* mtdpart_setup() parses into here */
static struct cmdline_mtd_partition *partitions;

/* the command line passed to mtdpart_setupd() */
static char *cmdline;
static int cmdline_parsed = 0;

/*
 * Parse one partition definition for an MTD. Since there can be many
 * comma separated partition definitions, this function calls itself
 * recursively until no more partition definitions are found. Nice side
 * effect: the memory to keep the mtd_partition structs and the names
 * is allocated upon the last definition being found. At that point the
 * syntax has been verified ok.
 */
static struct mtd_partition * newpart(char *s,
                                      char **retptr,
                                      int *num_parts,
                                      int this_part,
                                      unsigned char **extra_mem_ptr,
                                      int extra_mem_size)
{
	struct mtd_partition *parts;
	unsigned long size;
	unsigned long offset = OFFSET_CONTINUOUS;
	char *name;
	int name_len;
	unsigned char *extra_mem;
	char delim;
	unsigned int mask_flags;

	/* fetch the partition size */
	if (*s == '-')
	{	/* assign all remaining space to this partition */
		size = SIZE_REMAINING;
		s++;
	}
	else
	{
		size = memparse(s, &s);
		if (size < PAGE_SIZE)
		{
			printk(KERN_ERR ERRP "partition size too small (%lx)\n", size);
			return NULL;
		}
	}

	/* fetch partition name and flags */
	mask_flags = 0; /* this is going to be a regular partition */
	delim = 0;
        /* check for offset */
        if (*s == '@')
	{
                s++;
                offset = memparse(s, &s);
        }
        /* now look for name */
	if (*s == '(')
	{
		delim = ')';
	}

	if (delim)
	{
		char *p;

	    	name = ++s;
		if ((p = strchr(name, delim)) == 0)
		{
			printk(KERN_ERR ERRP "no closing %c found in partition name\n", delim);
			return NULL;
		}
		name_len = p - name;
		s = p + 1;
	}
	else
	{
	    	name = NULL;
		name_len = 13; /* Partition_000 */
	}

	/* record name length for memory allocation later */
	extra_mem_size += name_len + 1;

        /* test for options */
        if (strncmp(s, "ro", 2) == 0)
	{
		mask_flags |= MTD_WRITEABLE;
		s += 2;
        }

	/* test if more partitions are following */
	if (*s == ',')
	{
		if (size == SIZE_REMAINING)
		{
			printk(KERN_ERR ERRP "no partitions allowed after a fill-up partition\n");
			return NULL;
		}
		/* more partitions follow, parse them */
		if ((parts = newpart(s + 1, &s, num_parts,
		                     this_part + 1, &extra_mem, extra_mem_size)) == 0)
		  return NULL;
	}
	else
	{	/* this is the last partition: allocate space for all */
		int alloc_size;

		*num_parts = this_part + 1;
		alloc_size = *num_parts * sizeof(struct mtd_partition) +
			     extra_mem_size;
		parts = kmalloc(alloc_size, GFP_KERNEL);
		if (!parts)
		{
			printk(KERN_ERR ERRP "out of memory\n");
			return NULL;
		}
		memset(parts, 0, alloc_size);
		extra_mem = (unsigned char *)(parts + *num_parts);
	}
	/* enter this partition (offset will be calculated later if it is zero at this point) */
	parts[this_part].size = size;
	parts[this_part].offset = offset;
	parts[this_part].mask_flags = mask_flags;
	if (name)
	{
		strlcpy(extra_mem, name, name_len + 1);
	}
	else
	{
		sprintf(extra_mem, "Partition_%03d", this_part);
	}
	parts[this_part].name = extra_mem;
	extra_mem += name_len + 1;

	dbg(("partition %d: name <%s>, offset %x, size %x, mask flags %x\n",
	     this_part,
	     parts[this_part].name,
	     parts[this_part].offset,
	     parts[this_part].size,
	     parts[this_part].mask_flags));

	/* return (updated) pointer to extra_mem memory */
	if (extra_mem_ptr)
	  *extra_mem_ptr = extra_mem;

	/* return (updated) pointer command line string */
	*retptr = s;

	/* return partition table */
	return parts;
}

/*
 * Parse the command line.
 */
static int mtdpart_setup_real(char *s)
{
	cmdline_parsed = 1;

	for( ; s != NULL; )
	{
		struct cmdline_mtd_partition *this_mtd;
		struct mtd_partition *parts;
	    	int mtd_id_len;
		int num_parts;
		char *p, *mtd_id;

	    	mtd_id = s;
		/* fetch <mtd-id> */
		if (!(p = strchr(s, ':')))
		{
			printk(KERN_ERR ERRP "no mtd-id\n");
			return 0;
		}
		mtd_id_len = p - mtd_id;

		dbg(("parsing <%s>\n", p+1));

		/*
		 * parse one mtd. have it reserve memory for the
		 * struct cmdline_mtd_partition and the mtd-id string.
		 */
		parts = newpart(p + 1,		/* cmdline */
				&s,		/* out: updated cmdline ptr */
				&num_parts,	/* out: number of parts */
				0,		/* first partition */
				(unsigned char**)&this_mtd, /* out: extra mem */
				mtd_id_len + 1 + sizeof(*this_mtd) +
				sizeof(void*)-1 /*alignment*/);
		if(!parts)
		{
			/*
			 * An error occurred. We're either:
			 * a) out of memory, or
			 * b) in the middle of the partition spec
			 * Either way, this mtd is hosed and we're
			 * unlikely to succeed in parsing any more
			 */
			 return 0;
		 }

		/* align this_mtd */
		this_mtd = (struct cmdline_mtd_partition *)
			ALIGN((unsigned long)this_mtd, sizeof(void*));
		/* enter results */
		this_mtd->parts = parts;
		this_mtd->num_parts = num_parts;
		this_mtd->mtd_id = (char*)(this_mtd + 1);
		strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);

		/* link into chain */
		this_mtd->next = partitions;
		partitions = this_mtd;

		dbg(("mtdid=<%s> num_parts=<%d>\n",
		     this_mtd->mtd_id, this_mtd->num_parts));


		/* EOS - we're done */
		if (*s == 0)
			break;

		/* does another spec follow? */
		if (*s != ';')
		{
			printk(KERN_ERR ERRP "bad character after partition (%c)\n", *s);
			return 0;
		}
		s++;
	}
	return 1;
}

/*
 * Main function to be called from the MTD mapping driver/device to
 * obtain the partitioning information. At this point the command line
 * arguments will actually be parsed and turned to struct mtd_partition
 * information. It returns partitions for the requested mtd device, or
 * the first one in the chain if a NULL mtd_id is passed in.
 */
static int parse_cmdline_partitions(struct mtd_info *master,
                             struct mtd_partition **pparts,
                             unsigned long origin)
{
	unsigned long offset;
	int i;
	struct cmdline_mtd_partition *part;
	char *mtd_id = master->name;

	if(!cmdline)
		return -EINVAL;

	/* parse command line */
	if (!cmdline_parsed)
		mtdpart_setup_real(cmdline);

	for(part = partitions; part; part = part->next)
	{
		if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
		{
			for(i = 0, offset = 0; i < part->num_parts; i++)
			{
				if (part->parts[i].offset == OFFSET_CONTINUOUS)
				  part->parts[i].offset = offset;
				else
				  offset = part->parts[i].offset;
				if (part->parts[i].size == SIZE_REMAINING)
				  part->parts[i].size = master->size - offset;
				if (offset + part->parts[i].size > master->size)
				{
					printk(KERN_WARNING ERRP
					       "%s: partitioning exceeds flash size, truncating\n",
					       part->mtd_id);
					part->parts[i].size = master->size - offset;
					part->num_parts = i;
				}
				offset += part->parts[i].size;
			}
			*pparts = part->parts;
			return part->num_parts;
		}
	}
	return -EINVAL;
}


/*
 * This is the handler for our kernel parameter, called from
 * main.c::checksetup(). Note that we can not yet kmalloc() anything,
 * so we only save the commandline for later processing.
 *
 * This function needs to be visible for bootloaders.
 */
static int mtdpart_setup(char *s)
{
	cmdline = s;
	return 1;
}

__setup("mtdparts=", mtdpart_setup);

static struct mtd_part_parser cmdline_parser = {
	.owner = THIS_MODULE,
	.parse_fn = parse_cmdline_partitions,
	.name = "cmdlinepart",
};

static int __init cmdline_parser_init(void)
{
	return register_mtd_parser(&cmdline_parser);
}

module_init(cmdline_parser_init);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
MODULE_DESCRIPTION("Command line configuration of MTD partitions");