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
33 struct 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
45 struct fis_list {
46 struct fis_image_desc *img;
47 struct fis_list *next;
48 };
49
50 static int directory = CONFIG_MTD_REDBOOT_DIRECTORY_BLOCK;
51 module_param(directory, int, 0);
52
redboot_checksum(struct fis_image_desc * img)53 static 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
parse_redboot_partitions(struct mtd_info * master,struct mtd_partition ** pparts,struct mtd_part_parser_data * data)59 static 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_can_have_bb(master) &&
82 mtd_block_isbad(master, offset)) {
83 if (!offset) {
84 nogood:
85 printk(KERN_NOTICE "Failed to find a non-bad block to check for RedBoot partition table\n");
86 return -EIO;
87 }
88 offset -= master->erasesize;
89 }
90 } else {
91 offset = directory * master->erasesize;
92 while (mtd_can_have_bb(master) &&
93 mtd_block_isbad(master, offset)) {
94 offset += master->erasesize;
95 if (offset == master->size)
96 goto nogood;
97 }
98 }
99 buf = vmalloc(master->erasesize);
100
101 if (!buf)
102 return -ENOMEM;
103
104 printk(KERN_NOTICE "Searching for RedBoot partition table in %s at offset 0x%lx\n",
105 master->name, offset);
106
107 ret = mtd_read(master, offset, master->erasesize, &retlen,
108 (void *)buf);
109
110 if (ret)
111 goto out;
112
113 if (retlen != master->erasesize) {
114 ret = -EIO;
115 goto out;
116 }
117
118 numslots = (master->erasesize / sizeof(struct fis_image_desc));
119 for (i = 0; i < numslots; i++) {
120 if (!memcmp(buf[i].name, "FIS directory", 14)) {
121 /* This is apparently the FIS directory entry for the
122 * FIS directory itself. The FIS directory size is
123 * one erase block; if the buf[i].size field is
124 * swab32(erasesize) then we know we are looking at
125 * a byte swapped FIS directory - swap all the entries!
126 * (NOTE: this is 'size' not 'data_length'; size is
127 * the full size of the entry.)
128 */
129
130 /* RedBoot can combine the FIS directory and
131 config partitions into a single eraseblock;
132 we assume wrong-endian if either the swapped
133 'size' matches the eraseblock size precisely,
134 or if the swapped size actually fits in an
135 eraseblock while the unswapped size doesn't. */
136 if (swab32(buf[i].size) == master->erasesize ||
137 (buf[i].size > master->erasesize
138 && swab32(buf[i].size) < master->erasesize)) {
139 int j;
140 /* Update numslots based on actual FIS directory size */
141 numslots = swab32(buf[i].size) / sizeof (struct fis_image_desc);
142 for (j = 0; j < numslots; ++j) {
143
144 /* A single 0xff denotes a deleted entry.
145 * Two of them in a row is the end of the table.
146 */
147 if (buf[j].name[0] == 0xff) {
148 if (buf[j].name[1] == 0xff) {
149 break;
150 } else {
151 continue;
152 }
153 }
154
155 /* The unsigned long fields were written with the
156 * wrong byte sex, name and pad have no byte sex.
157 */
158 swab32s(&buf[j].flash_base);
159 swab32s(&buf[j].mem_base);
160 swab32s(&buf[j].size);
161 swab32s(&buf[j].entry_point);
162 swab32s(&buf[j].data_length);
163 swab32s(&buf[j].desc_cksum);
164 swab32s(&buf[j].file_cksum);
165 }
166 } else if (buf[i].size < master->erasesize) {
167 /* Update numslots based on actual FIS directory size */
168 numslots = buf[i].size / sizeof(struct fis_image_desc);
169 }
170 break;
171 }
172 }
173 if (i == numslots) {
174 /* Didn't find it */
175 printk(KERN_NOTICE "No RedBoot partition table detected in %s\n",
176 master->name);
177 ret = 0;
178 goto out;
179 }
180
181 for (i = 0; i < numslots; i++) {
182 struct fis_list *new_fl, **prev;
183
184 if (buf[i].name[0] == 0xff) {
185 if (buf[i].name[1] == 0xff) {
186 break;
187 } else {
188 continue;
189 }
190 }
191 if (!redboot_checksum(&buf[i]))
192 break;
193
194 new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL);
195 namelen += strlen(buf[i].name)+1;
196 if (!new_fl) {
197 ret = -ENOMEM;
198 goto out;
199 }
200 new_fl->img = &buf[i];
201 if (data && data->origin)
202 buf[i].flash_base -= data->origin;
203 else
204 buf[i].flash_base &= master->size-1;
205
206 /* I'm sure the JFFS2 code has done me permanent damage.
207 * I now think the following is _normal_
208 */
209 prev = &fl;
210 while(*prev && (*prev)->img->flash_base < new_fl->img->flash_base)
211 prev = &(*prev)->next;
212 new_fl->next = *prev;
213 *prev = new_fl;
214
215 nrparts++;
216 }
217 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
218 if (fl->img->flash_base) {
219 nrparts++;
220 nulllen = sizeof(nullstring);
221 }
222
223 for (tmp_fl = fl; tmp_fl->next; tmp_fl = tmp_fl->next) {
224 if (tmp_fl->img->flash_base + tmp_fl->img->size + master->erasesize <= tmp_fl->next->img->flash_base) {
225 nrparts++;
226 nulllen = sizeof(nullstring);
227 }
228 }
229 #endif
230 parts = kzalloc(sizeof(*parts)*nrparts + nulllen + namelen, GFP_KERNEL);
231
232 if (!parts) {
233 ret = -ENOMEM;
234 goto out;
235 }
236
237 nullname = (char *)&parts[nrparts];
238 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
239 if (nulllen > 0) {
240 strcpy(nullname, nullstring);
241 }
242 #endif
243 names = nullname + nulllen;
244
245 i=0;
246
247 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
248 if (fl->img->flash_base) {
249 parts[0].name = nullname;
250 parts[0].size = fl->img->flash_base;
251 parts[0].offset = 0;
252 i++;
253 }
254 #endif
255 for ( ; i<nrparts; i++) {
256 parts[i].size = fl->img->size;
257 parts[i].offset = fl->img->flash_base;
258 parts[i].name = names;
259
260 strcpy(names, fl->img->name);
261 #ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
262 if (!memcmp(names, "RedBoot", 8) ||
263 !memcmp(names, "RedBoot config", 15) ||
264 !memcmp(names, "FIS directory", 14)) {
265 parts[i].mask_flags = MTD_WRITEABLE;
266 }
267 #endif
268 names += strlen(names)+1;
269
270 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
271 if(fl->next && fl->img->flash_base + fl->img->size + master->erasesize <= fl->next->img->flash_base) {
272 i++;
273 parts[i].offset = parts[i-1].size + parts[i-1].offset;
274 parts[i].size = fl->next->img->flash_base - parts[i].offset;
275 parts[i].name = nullname;
276 }
277 #endif
278 tmp_fl = fl;
279 fl = fl->next;
280 kfree(tmp_fl);
281 }
282 ret = nrparts;
283 *pparts = parts;
284 out:
285 while (fl) {
286 struct fis_list *old = fl;
287 fl = fl->next;
288 kfree(old);
289 }
290 vfree(buf);
291 return ret;
292 }
293
294 static struct mtd_part_parser redboot_parser = {
295 .owner = THIS_MODULE,
296 .parse_fn = parse_redboot_partitions,
297 .name = "RedBoot",
298 };
299
300 /* mtd parsers will request the module by parser name */
301 MODULE_ALIAS("RedBoot");
302
redboot_parser_init(void)303 static int __init redboot_parser_init(void)
304 {
305 return register_mtd_parser(&redboot_parser);
306 }
307
redboot_parser_exit(void)308 static void __exit redboot_parser_exit(void)
309 {
310 deregister_mtd_parser(&redboot_parser);
311 }
312
313 module_init(redboot_parser_init);
314 module_exit(redboot_parser_exit);
315
316 MODULE_LICENSE("GPL");
317 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
318 MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");
319