Root/drivers/mtd/cmdlinepart.c

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

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