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801c135c AB |
1 | /* |
2 | * Copyright (c) International Business Machines Corp., 2006 | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See | |
12 | * the GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write to the Free Software | |
16 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
17 | * | |
18 | * Author: Artem Bityutskiy (Битюцкий Артём), Joern Engel | |
19 | */ | |
20 | ||
21 | /* | |
22 | * This file includes implementation of fake MTD devices for each UBI volume. | |
23 | * This sounds strange, but it is in fact quite useful to make MTD-oriented | |
24 | * software (including all the legacy software) to work on top of UBI. | |
25 | * | |
26 | * Gluebi emulates MTD devices of "MTD_UBIVOLUME" type. Their minimal I/O unit | |
27 | * size (mtd->writesize) is equivalent to the UBI minimal I/O unit. The | |
28 | * eraseblock size is equivalent to the logical eraseblock size of the volume. | |
29 | */ | |
30 | ||
3013ee31 | 31 | #include <linux/math64.h> |
801c135c AB |
32 | #include "ubi.h" |
33 | ||
34 | /** | |
35 | * gluebi_get_device - get MTD device reference. | |
36 | * @mtd: the MTD device description object | |
37 | * | |
38 | * This function is called every time the MTD device is being opened and | |
39 | * implements the MTD get_device() operation. Returns zero in case of success | |
40 | * and a negative error code in case of failure. | |
41 | */ | |
42 | static int gluebi_get_device(struct mtd_info *mtd) | |
43 | { | |
44 | struct ubi_volume *vol; | |
45 | ||
46 | vol = container_of(mtd, struct ubi_volume, gluebi_mtd); | |
47 | ||
48 | /* | |
49 | * We do not introduce locks for gluebi reference count because the | |
50 | * get_device()/put_device() calls are already serialized at MTD. | |
51 | */ | |
52 | if (vol->gluebi_refcount > 0) { | |
53 | /* | |
54 | * The MTD device is already referenced and this is just one | |
55 | * more reference. MTD allows many users to open the same | |
56 | * volume simultaneously and do not distinguish between | |
57 | * readers/writers/exclusive openers as UBI does. So we do not | |
58 | * open the UBI volume again - just increase the reference | |
59 | * counter and return. | |
60 | */ | |
61 | vol->gluebi_refcount += 1; | |
62 | return 0; | |
63 | } | |
64 | ||
65 | /* | |
66 | * This is the first reference to this UBI volume via the MTD device | |
67 | * interface. Open the corresponding volume in read-write mode. | |
68 | */ | |
69 | vol->gluebi_desc = ubi_open_volume(vol->ubi->ubi_num, vol->vol_id, | |
70 | UBI_READWRITE); | |
71 | if (IS_ERR(vol->gluebi_desc)) | |
72 | return PTR_ERR(vol->gluebi_desc); | |
73 | vol->gluebi_refcount += 1; | |
74 | return 0; | |
75 | } | |
76 | ||
77 | /** | |
78 | * gluebi_put_device - put MTD device reference. | |
79 | * @mtd: the MTD device description object | |
80 | * | |
81 | * This function is called every time the MTD device is being put. Returns | |
82 | * zero in case of success and a negative error code in case of failure. | |
83 | */ | |
84 | static void gluebi_put_device(struct mtd_info *mtd) | |
85 | { | |
86 | struct ubi_volume *vol; | |
87 | ||
88 | vol = container_of(mtd, struct ubi_volume, gluebi_mtd); | |
89 | vol->gluebi_refcount -= 1; | |
90 | ubi_assert(vol->gluebi_refcount >= 0); | |
91 | if (vol->gluebi_refcount == 0) | |
92 | ubi_close_volume(vol->gluebi_desc); | |
93 | } | |
94 | ||
95 | /** | |
96 | * gluebi_read - read operation of emulated MTD devices. | |
97 | * @mtd: MTD device description object | |
98 | * @from: absolute offset from where to read | |
99 | * @len: how many bytes to read | |
100 | * @retlen: count of read bytes is returned here | |
101 | * @buf: buffer to store the read data | |
102 | * | |
103 | * This function returns zero in case of success and a negative error code in | |
104 | * case of failure. | |
105 | */ | |
106 | static int gluebi_read(struct mtd_info *mtd, loff_t from, size_t len, | |
107 | size_t *retlen, unsigned char *buf) | |
108 | { | |
109 | int err = 0, lnum, offs, total_read; | |
110 | struct ubi_volume *vol; | |
111 | struct ubi_device *ubi; | |
801c135c | 112 | |
c8566350 | 113 | dbg_gen("read %zd bytes from offset %lld", len, from); |
801c135c AB |
114 | |
115 | if (len < 0 || from < 0 || from + len > mtd->size) | |
116 | return -EINVAL; | |
117 | ||
118 | vol = container_of(mtd, struct ubi_volume, gluebi_mtd); | |
119 | ubi = vol->ubi; | |
120 | ||
3013ee31 | 121 | lnum = div_u64_rem(from, mtd->erasesize, &offs); |
801c135c AB |
122 | total_read = len; |
123 | while (total_read) { | |
124 | size_t to_read = mtd->erasesize - offs; | |
125 | ||
126 | if (to_read > total_read) | |
127 | to_read = total_read; | |
128 | ||
89b96b69 | 129 | err = ubi_eba_read_leb(ubi, vol, lnum, buf, offs, to_read, 0); |
801c135c AB |
130 | if (err) |
131 | break; | |
132 | ||
133 | lnum += 1; | |
134 | offs = 0; | |
135 | total_read -= to_read; | |
136 | buf += to_read; | |
137 | } | |
138 | ||
139 | *retlen = len - total_read; | |
140 | return err; | |
141 | } | |
142 | ||
143 | /** | |
144 | * gluebi_write - write operation of emulated MTD devices. | |
145 | * @mtd: MTD device description object | |
146 | * @to: absolute offset where to write | |
147 | * @len: how many bytes to write | |
148 | * @retlen: count of written bytes is returned here | |
149 | * @buf: buffer with data to write | |
150 | * | |
151 | * This function returns zero in case of success and a negative error code in | |
152 | * case of failure. | |
153 | */ | |
154 | static int gluebi_write(struct mtd_info *mtd, loff_t to, size_t len, | |
155 | size_t *retlen, const u_char *buf) | |
156 | { | |
157 | int err = 0, lnum, offs, total_written; | |
158 | struct ubi_volume *vol; | |
159 | struct ubi_device *ubi; | |
801c135c | 160 | |
c8566350 | 161 | dbg_gen("write %zd bytes to offset %lld", len, to); |
801c135c AB |
162 | |
163 | if (len < 0 || to < 0 || len + to > mtd->size) | |
164 | return -EINVAL; | |
165 | ||
166 | vol = container_of(mtd, struct ubi_volume, gluebi_mtd); | |
167 | ubi = vol->ubi; | |
168 | ||
169 | if (ubi->ro_mode) | |
170 | return -EROFS; | |
171 | ||
3013ee31 | 172 | lnum = div_u64_rem(to, mtd->erasesize, &offs); |
801c135c AB |
173 | |
174 | if (len % mtd->writesize || offs % mtd->writesize) | |
175 | return -EINVAL; | |
176 | ||
177 | total_written = len; | |
178 | while (total_written) { | |
179 | size_t to_write = mtd->erasesize - offs; | |
180 | ||
181 | if (to_write > total_written) | |
182 | to_write = total_written; | |
183 | ||
89b96b69 AB |
184 | err = ubi_eba_write_leb(ubi, vol, lnum, buf, offs, to_write, |
185 | UBI_UNKNOWN); | |
801c135c AB |
186 | if (err) |
187 | break; | |
188 | ||
189 | lnum += 1; | |
190 | offs = 0; | |
191 | total_written -= to_write; | |
192 | buf += to_write; | |
193 | } | |
194 | ||
195 | *retlen = len - total_written; | |
196 | return err; | |
197 | } | |
198 | ||
199 | /** | |
200 | * gluebi_erase - erase operation of emulated MTD devices. | |
201 | * @mtd: the MTD device description object | |
202 | * @instr: the erase operation description | |
203 | * | |
204 | * This function calls the erase callback when finishes. Returns zero in case | |
205 | * of success and a negative error code in case of failure. | |
206 | */ | |
207 | static int gluebi_erase(struct mtd_info *mtd, struct erase_info *instr) | |
208 | { | |
209 | int err, i, lnum, count; | |
210 | struct ubi_volume *vol; | |
211 | struct ubi_device *ubi; | |
212 | ||
69423d99 AH |
213 | dbg_gen("erase %llu bytes at offset %llu", (unsigned long long)instr->len, |
214 | (unsigned long long)instr->addr); | |
801c135c AB |
215 | |
216 | if (instr->addr < 0 || instr->addr > mtd->size - mtd->erasesize) | |
217 | return -EINVAL; | |
218 | ||
219 | if (instr->len < 0 || instr->addr + instr->len > mtd->size) | |
220 | return -EINVAL; | |
221 | ||
69423d99 | 222 | if (mtd_mod_by_ws(instr->addr, mtd) || mtd_mod_by_ws(instr->len, mtd)) |
801c135c AB |
223 | return -EINVAL; |
224 | ||
69423d99 AH |
225 | lnum = mtd_div_by_eb(instr->addr, mtd); |
226 | count = mtd_div_by_eb(instr->len, mtd); | |
801c135c AB |
227 | |
228 | vol = container_of(mtd, struct ubi_volume, gluebi_mtd); | |
229 | ubi = vol->ubi; | |
230 | ||
231 | if (ubi->ro_mode) | |
232 | return -EROFS; | |
233 | ||
234 | for (i = 0; i < count; i++) { | |
89b96b69 | 235 | err = ubi_eba_unmap_leb(ubi, vol, lnum + i); |
801c135c AB |
236 | if (err) |
237 | goto out_err; | |
238 | } | |
239 | ||
240 | /* | |
241 | * MTD erase operations are synchronous, so we have to make sure the | |
242 | * physical eraseblock is wiped out. | |
243 | */ | |
244 | err = ubi_wl_flush(ubi); | |
245 | if (err) | |
246 | goto out_err; | |
247 | ||
9c9ec147 AB |
248 | instr->state = MTD_ERASE_DONE; |
249 | mtd_erase_callback(instr); | |
801c135c AB |
250 | return 0; |
251 | ||
252 | out_err: | |
253 | instr->state = MTD_ERASE_FAILED; | |
69423d99 | 254 | instr->fail_addr = (long long)lnum * mtd->erasesize; |
801c135c AB |
255 | return err; |
256 | } | |
257 | ||
258 | /** | |
259 | * ubi_create_gluebi - initialize gluebi for an UBI volume. | |
260 | * @ubi: UBI device description object | |
261 | * @vol: volume description object | |
262 | * | |
263 | * This function is called when an UBI volume is created in order to create | |
264 | * corresponding fake MTD device. Returns zero in case of success and a | |
265 | * negative error code in case of failure. | |
266 | */ | |
267 | int ubi_create_gluebi(struct ubi_device *ubi, struct ubi_volume *vol) | |
268 | { | |
801c135c AB |
269 | struct mtd_info *mtd = &vol->gluebi_mtd; |
270 | ||
271 | mtd->name = kmemdup(vol->name, vol->name_len + 1, GFP_KERNEL); | |
272 | if (!mtd->name) | |
273 | return -ENOMEM; | |
274 | ||
275 | mtd->type = MTD_UBIVOLUME; | |
276 | if (!ubi->ro_mode) | |
277 | mtd->flags = MTD_WRITEABLE; | |
278 | mtd->writesize = ubi->min_io_size; | |
279 | mtd->owner = THIS_MODULE; | |
801c135c AB |
280 | mtd->erasesize = vol->usable_leb_size; |
281 | mtd->read = gluebi_read; | |
282 | mtd->write = gluebi_write; | |
283 | mtd->erase = gluebi_erase; | |
284 | mtd->get_device = gluebi_get_device; | |
285 | mtd->put_device = gluebi_put_device; | |
286 | ||
941dfb07 AB |
287 | /* |
288 | * In case of dynamic volume, MTD device size is just volume size. In | |
289 | * case of a static volume the size is equivalent to the amount of data | |
cbd8a9d2 | 290 | * bytes. |
941dfb07 AB |
291 | */ |
292 | if (vol->vol_type == UBI_DYNAMIC_VOLUME) | |
69423d99 | 293 | mtd->size = (long long)vol->usable_leb_size * vol->reserved_pebs; |
cbd8a9d2 JA |
294 | else |
295 | mtd->size = vol->used_bytes; | |
941dfb07 | 296 | |
801c135c | 297 | if (add_mtd_device(mtd)) { |
bb84c1a1 | 298 | ubi_err("cannot not add MTD device"); |
801c135c AB |
299 | kfree(mtd->name); |
300 | return -ENFILE; | |
301 | } | |
302 | ||
69423d99 AH |
303 | dbg_gen("added mtd%d (\"%s\"), size %llu, EB size %u", |
304 | mtd->index, mtd->name, (unsigned long long)mtd->size, mtd->erasesize); | |
801c135c AB |
305 | return 0; |
306 | } | |
307 | ||
308 | /** | |
309 | * ubi_destroy_gluebi - close gluebi for an UBI volume. | |
310 | * @vol: volume description object | |
311 | * | |
312 | * This function is called when an UBI volume is removed in order to remove | |
313 | * corresponding fake MTD device. Returns zero in case of success and a | |
314 | * negative error code in case of failure. | |
315 | */ | |
316 | int ubi_destroy_gluebi(struct ubi_volume *vol) | |
317 | { | |
318 | int err; | |
319 | struct mtd_info *mtd = &vol->gluebi_mtd; | |
320 | ||
c8566350 | 321 | dbg_gen("remove mtd%d", mtd->index); |
801c135c AB |
322 | err = del_mtd_device(mtd); |
323 | if (err) | |
324 | return err; | |
325 | kfree(mtd->name); | |
326 | return 0; | |
327 | } | |
941dfb07 AB |
328 | |
329 | /** | |
330 | * ubi_gluebi_updated - UBI volume was updated notifier. | |
331 | * @vol: volume description object | |
332 | * | |
333 | * This function is called every time an UBI volume is updated. This function | |
334 | * does nothing if volume @vol is dynamic, and changes MTD device size if the | |
335 | * volume is static. This is needed because static volumes cannot be read past | |
336 | * data they contain. | |
337 | */ | |
338 | void ubi_gluebi_updated(struct ubi_volume *vol) | |
339 | { | |
340 | struct mtd_info *mtd = &vol->gluebi_mtd; | |
341 | ||
342 | if (vol->vol_type == UBI_STATIC_VOLUME) | |
343 | mtd->size = vol->used_bytes; | |
344 | } |