Root/drivers/mtd/redboot.c

1/*
2 * Parse RedBoot-style Flash Image System (FIS) tables and
3 * produce a Linux partition array to match.
4 *
5 * Copyright © 2001 Red Hat UK Limited
6 * Copyright © 2001-2010 David Woodhouse <dwmw2@infradead.org>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
21 *
22 */
23
24#include <linux/kernel.h>
25#include <linux/slab.h>
26#include <linux/init.h>
27#include <linux/vmalloc.h>
28
29#include <linux/mtd/mtd.h>
30#include <linux/mtd/partitions.h>
31#include <linux/module.h>
32
33struct fis_image_desc {
34    unsigned char name[16]; // Null terminated name
35    uint32_t flash_base; // Address within FLASH of image
36    uint32_t mem_base; // Address in memory where it executes
37    uint32_t size; // Length of image
38    uint32_t entry_point; // Execution entry point
39    uint32_t data_length; // Length of actual data
40    unsigned char _pad[256-(16+7*sizeof(uint32_t))];
41    uint32_t desc_cksum; // Checksum over image descriptor
42    uint32_t file_cksum; // Checksum over image data
43};
44
45struct fis_list {
46    struct fis_image_desc *img;
47    struct fis_list *next;
48};
49
50static int directory = CONFIG_MTD_REDBOOT_DIRECTORY_BLOCK;
51module_param(directory, int, 0);
52
53static inline int redboot_checksum(struct fis_image_desc *img)
54{
55    /* RedBoot doesn't actually write the desc_cksum field yet AFAICT */
56    return 1;
57}
58
59static int parse_redboot_partitions(struct mtd_info *master,
60                    struct mtd_partition **pparts,
61                    struct mtd_part_parser_data *data)
62{
63    int nrparts = 0;
64    struct fis_image_desc *buf;
65    struct mtd_partition *parts;
66    struct fis_list *fl = NULL, *tmp_fl;
67    int ret, i;
68    size_t retlen;
69    char *names;
70    char *nullname;
71    int namelen = 0;
72    int nulllen = 0;
73    int numslots;
74    unsigned long offset;
75#ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
76    static char nullstring[] = "unallocated";
77#endif
78
79    if ( directory < 0 ) {
80        offset = master->size + directory * master->erasesize;
81        while (mtd_block_isbad(master, offset)) {
82            if (!offset) {
83            nogood:
84                printk(KERN_NOTICE "Failed to find a non-bad block to check for RedBoot partition table\n");
85                return -EIO;
86            }
87            offset -= master->erasesize;
88        }
89    } else {
90        offset = directory * master->erasesize;
91        while (mtd_block_isbad(master, offset)) {
92            offset += master->erasesize;
93            if (offset == master->size)
94                goto nogood;
95        }
96    }
97    buf = vmalloc(master->erasesize);
98
99    if (!buf)
100        return -ENOMEM;
101
102    printk(KERN_NOTICE "Searching for RedBoot partition table in %s at offset 0x%lx\n",
103           master->name, offset);
104
105    ret = mtd_read(master, offset, master->erasesize, &retlen,
106               (void *)buf);
107
108    if (ret)
109        goto out;
110
111    if (retlen != master->erasesize) {
112        ret = -EIO;
113        goto out;
114    }
115
116    numslots = (master->erasesize / sizeof(struct fis_image_desc));
117    for (i = 0; i < numslots; i++) {
118        if (!memcmp(buf[i].name, "FIS directory", 14)) {
119            /* This is apparently the FIS directory entry for the
120             * FIS directory itself. The FIS directory size is
121             * one erase block; if the buf[i].size field is
122             * swab32(erasesize) then we know we are looking at
123             * a byte swapped FIS directory - swap all the entries!
124             * (NOTE: this is 'size' not 'data_length'; size is
125             * the full size of the entry.)
126             */
127
128            /* RedBoot can combine the FIS directory and
129               config partitions into a single eraseblock;
130               we assume wrong-endian if either the swapped
131               'size' matches the eraseblock size precisely,
132               or if the swapped size actually fits in an
133               eraseblock while the unswapped size doesn't. */
134            if (swab32(buf[i].size) == master->erasesize ||
135                (buf[i].size > master->erasesize
136                 && swab32(buf[i].size) < master->erasesize)) {
137                int j;
138                /* Update numslots based on actual FIS directory size */
139                numslots = swab32(buf[i].size) / sizeof (struct fis_image_desc);
140                for (j = 0; j < numslots; ++j) {
141
142                    /* A single 0xff denotes a deleted entry.
143                     * Two of them in a row is the end of the table.
144                     */
145                    if (buf[j].name[0] == 0xff) {
146                          if (buf[j].name[1] == 0xff) {
147                            break;
148                        } else {
149                            continue;
150                        }
151                    }
152
153                    /* The unsigned long fields were written with the
154                     * wrong byte sex, name and pad have no byte sex.
155                     */
156                    swab32s(&buf[j].flash_base);
157                    swab32s(&buf[j].mem_base);
158                    swab32s(&buf[j].size);
159                    swab32s(&buf[j].entry_point);
160                    swab32s(&buf[j].data_length);
161                    swab32s(&buf[j].desc_cksum);
162                    swab32s(&buf[j].file_cksum);
163                }
164            } else if (buf[i].size < master->erasesize) {
165                /* Update numslots based on actual FIS directory size */
166                numslots = buf[i].size / sizeof(struct fis_image_desc);
167            }
168            break;
169        }
170    }
171    if (i == numslots) {
172        /* Didn't find it */
173        printk(KERN_NOTICE "No RedBoot partition table detected in %s\n",
174               master->name);
175        ret = 0;
176        goto out;
177    }
178
179    for (i = 0; i < numslots; i++) {
180        struct fis_list *new_fl, **prev;
181
182        if (buf[i].name[0] == 0xff) {
183            if (buf[i].name[1] == 0xff) {
184                break;
185            } else {
186                continue;
187            }
188        }
189        if (!redboot_checksum(&buf[i]))
190            break;
191
192        new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL);
193        namelen += strlen(buf[i].name)+1;
194        if (!new_fl) {
195            ret = -ENOMEM;
196            goto out;
197        }
198        new_fl->img = &buf[i];
199        if (data && data->origin)
200            buf[i].flash_base -= data->origin;
201        else
202            buf[i].flash_base &= master->size-1;
203
204        /* I'm sure the JFFS2 code has done me permanent damage.
205         * I now think the following is _normal_
206         */
207        prev = &fl;
208        while(*prev && (*prev)->img->flash_base < new_fl->img->flash_base)
209            prev = &(*prev)->next;
210        new_fl->next = *prev;
211        *prev = new_fl;
212
213        nrparts++;
214    }
215#ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
216    if (fl->img->flash_base) {
217        nrparts++;
218        nulllen = sizeof(nullstring);
219    }
220
221    for (tmp_fl = fl; tmp_fl->next; tmp_fl = tmp_fl->next) {
222        if (tmp_fl->img->flash_base + tmp_fl->img->size + master->erasesize <= tmp_fl->next->img->flash_base) {
223            nrparts++;
224            nulllen = sizeof(nullstring);
225        }
226    }
227#endif
228    parts = kzalloc(sizeof(*parts)*nrparts + nulllen + namelen, GFP_KERNEL);
229
230    if (!parts) {
231        ret = -ENOMEM;
232        goto out;
233    }
234
235    nullname = (char *)&parts[nrparts];
236#ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
237    if (nulllen > 0) {
238        strcpy(nullname, nullstring);
239    }
240#endif
241    names = nullname + nulllen;
242
243    i=0;
244
245#ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
246    if (fl->img->flash_base) {
247           parts[0].name = nullname;
248           parts[0].size = fl->img->flash_base;
249           parts[0].offset = 0;
250        i++;
251    }
252#endif
253    for ( ; i<nrparts; i++) {
254        parts[i].size = fl->img->size;
255        parts[i].offset = fl->img->flash_base;
256        parts[i].name = names;
257
258        strcpy(names, fl->img->name);
259#ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
260        if (!memcmp(names, "RedBoot", 8) ||
261                !memcmp(names, "RedBoot config", 15) ||
262                !memcmp(names, "FIS directory", 14)) {
263            parts[i].mask_flags = MTD_WRITEABLE;
264        }
265#endif
266        names += strlen(names)+1;
267
268#ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
269        if(fl->next && fl->img->flash_base + fl->img->size + master->erasesize <= fl->next->img->flash_base) {
270            i++;
271            parts[i].offset = parts[i-1].size + parts[i-1].offset;
272            parts[i].size = fl->next->img->flash_base - parts[i].offset;
273            parts[i].name = nullname;
274        }
275#endif
276        tmp_fl = fl;
277        fl = fl->next;
278        kfree(tmp_fl);
279    }
280    ret = nrparts;
281    *pparts = parts;
282 out:
283    while (fl) {
284        struct fis_list *old = fl;
285        fl = fl->next;
286        kfree(old);
287    }
288    vfree(buf);
289    return ret;
290}
291
292static struct mtd_part_parser redboot_parser = {
293    .owner = THIS_MODULE,
294    .parse_fn = parse_redboot_partitions,
295    .name = "RedBoot",
296};
297
298/* mtd parsers will request the module by parser name */
299MODULE_ALIAS("RedBoot");
300
301static int __init redboot_parser_init(void)
302{
303    return register_mtd_parser(&redboot_parser);
304}
305
306static void __exit redboot_parser_exit(void)
307{
308    deregister_mtd_parser(&redboot_parser);
309}
310
311module_init(redboot_parser_init);
312module_exit(redboot_parser_exit);
313
314MODULE_LICENSE("GPL");
315MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
316MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");
317

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