Commit | Line | Data |
---|---|---|
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 | ||
31 | #include <asm/div64.h> | |
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; | |
112 | uint64_t tmp = from; | |
113 | ||
114 | dbg_msg("read %zd bytes from offset %lld", len, from); | |
115 | ||
116 | if (len < 0 || from < 0 || from + len > mtd->size) | |
117 | return -EINVAL; | |
118 | ||
119 | vol = container_of(mtd, struct ubi_volume, gluebi_mtd); | |
120 | ubi = vol->ubi; | |
121 | ||
122 | offs = do_div(tmp, mtd->erasesize); | |
123 | lnum = tmp; | |
124 | ||
125 | total_read = len; | |
126 | while (total_read) { | |
127 | size_t to_read = mtd->erasesize - offs; | |
128 | ||
129 | if (to_read > total_read) | |
130 | to_read = total_read; | |
131 | ||
132 | err = ubi_eba_read_leb(ubi, vol->vol_id, lnum, buf, offs, | |
133 | to_read, 0); | |
134 | if (err) | |
135 | break; | |
136 | ||
137 | lnum += 1; | |
138 | offs = 0; | |
139 | total_read -= to_read; | |
140 | buf += to_read; | |
141 | } | |
142 | ||
143 | *retlen = len - total_read; | |
144 | return err; | |
145 | } | |
146 | ||
147 | /** | |
148 | * gluebi_write - write operation of emulated MTD devices. | |
149 | * @mtd: MTD device description object | |
150 | * @to: absolute offset where to write | |
151 | * @len: how many bytes to write | |
152 | * @retlen: count of written bytes is returned here | |
153 | * @buf: buffer with data to write | |
154 | * | |
155 | * This function returns zero in case of success and a negative error code in | |
156 | * case of failure. | |
157 | */ | |
158 | static int gluebi_write(struct mtd_info *mtd, loff_t to, size_t len, | |
159 | size_t *retlen, const u_char *buf) | |
160 | { | |
161 | int err = 0, lnum, offs, total_written; | |
162 | struct ubi_volume *vol; | |
163 | struct ubi_device *ubi; | |
164 | uint64_t tmp = to; | |
165 | ||
166 | dbg_msg("write %zd bytes to offset %lld", len, to); | |
167 | ||
168 | if (len < 0 || to < 0 || len + to > mtd->size) | |
169 | return -EINVAL; | |
170 | ||
171 | vol = container_of(mtd, struct ubi_volume, gluebi_mtd); | |
172 | ubi = vol->ubi; | |
173 | ||
174 | if (ubi->ro_mode) | |
175 | return -EROFS; | |
176 | ||
177 | offs = do_div(tmp, mtd->erasesize); | |
178 | lnum = tmp; | |
179 | ||
180 | if (len % mtd->writesize || offs % mtd->writesize) | |
181 | return -EINVAL; | |
182 | ||
183 | total_written = len; | |
184 | while (total_written) { | |
185 | size_t to_write = mtd->erasesize - offs; | |
186 | ||
187 | if (to_write > total_written) | |
188 | to_write = total_written; | |
189 | ||
190 | err = ubi_eba_write_leb(ubi, vol->vol_id, lnum, buf, offs, | |
191 | to_write, UBI_UNKNOWN); | |
192 | if (err) | |
193 | break; | |
194 | ||
195 | lnum += 1; | |
196 | offs = 0; | |
197 | total_written -= to_write; | |
198 | buf += to_write; | |
199 | } | |
200 | ||
201 | *retlen = len - total_written; | |
202 | return err; | |
203 | } | |
204 | ||
205 | /** | |
206 | * gluebi_erase - erase operation of emulated MTD devices. | |
207 | * @mtd: the MTD device description object | |
208 | * @instr: the erase operation description | |
209 | * | |
210 | * This function calls the erase callback when finishes. Returns zero in case | |
211 | * of success and a negative error code in case of failure. | |
212 | */ | |
213 | static int gluebi_erase(struct mtd_info *mtd, struct erase_info *instr) | |
214 | { | |
215 | int err, i, lnum, count; | |
216 | struct ubi_volume *vol; | |
217 | struct ubi_device *ubi; | |
218 | ||
219 | dbg_msg("erase %u bytes at offset %u", instr->len, instr->addr); | |
220 | ||
221 | if (instr->addr < 0 || instr->addr > mtd->size - mtd->erasesize) | |
222 | return -EINVAL; | |
223 | ||
224 | if (instr->len < 0 || instr->addr + instr->len > mtd->size) | |
225 | return -EINVAL; | |
226 | ||
227 | if (instr->addr % mtd->writesize || instr->len % mtd->writesize) | |
228 | return -EINVAL; | |
229 | ||
230 | lnum = instr->addr / mtd->erasesize; | |
231 | count = instr->len / mtd->erasesize; | |
232 | ||
233 | vol = container_of(mtd, struct ubi_volume, gluebi_mtd); | |
234 | ubi = vol->ubi; | |
235 | ||
236 | if (ubi->ro_mode) | |
237 | return -EROFS; | |
238 | ||
239 | for (i = 0; i < count; i++) { | |
240 | err = ubi_eba_unmap_leb(ubi, vol->vol_id, lnum + i); | |
241 | if (err) | |
242 | goto out_err; | |
243 | } | |
244 | ||
245 | /* | |
246 | * MTD erase operations are synchronous, so we have to make sure the | |
247 | * physical eraseblock is wiped out. | |
248 | */ | |
249 | err = ubi_wl_flush(ubi); | |
250 | if (err) | |
251 | goto out_err; | |
252 | ||
253 | instr->state = MTD_ERASE_DONE; | |
254 | mtd_erase_callback(instr); | |
255 | return 0; | |
256 | ||
257 | out_err: | |
258 | instr->state = MTD_ERASE_FAILED; | |
259 | instr->fail_addr = lnum * mtd->erasesize; | |
260 | return err; | |
261 | } | |
262 | ||
263 | /** | |
264 | * ubi_create_gluebi - initialize gluebi for an UBI volume. | |
265 | * @ubi: UBI device description object | |
266 | * @vol: volume description object | |
267 | * | |
268 | * This function is called when an UBI volume is created in order to create | |
269 | * corresponding fake MTD device. Returns zero in case of success and a | |
270 | * negative error code in case of failure. | |
271 | */ | |
272 | int ubi_create_gluebi(struct ubi_device *ubi, struct ubi_volume *vol) | |
273 | { | |
801c135c AB |
274 | struct mtd_info *mtd = &vol->gluebi_mtd; |
275 | ||
276 | mtd->name = kmemdup(vol->name, vol->name_len + 1, GFP_KERNEL); | |
277 | if (!mtd->name) | |
278 | return -ENOMEM; | |
279 | ||
280 | mtd->type = MTD_UBIVOLUME; | |
281 | if (!ubi->ro_mode) | |
282 | mtd->flags = MTD_WRITEABLE; | |
283 | mtd->writesize = ubi->min_io_size; | |
284 | mtd->owner = THIS_MODULE; | |
801c135c AB |
285 | mtd->erasesize = vol->usable_leb_size; |
286 | mtd->read = gluebi_read; | |
287 | mtd->write = gluebi_write; | |
288 | mtd->erase = gluebi_erase; | |
289 | mtd->get_device = gluebi_get_device; | |
290 | mtd->put_device = gluebi_put_device; | |
291 | ||
941dfb07 AB |
292 | /* |
293 | * In case of dynamic volume, MTD device size is just volume size. In | |
294 | * case of a static volume the size is equivalent to the amount of data | |
295 | * bytes, which is zero at this moment and will be changed after volume | |
296 | * update. | |
297 | */ | |
298 | if (vol->vol_type == UBI_DYNAMIC_VOLUME) | |
299 | mtd->size = vol->usable_leb_size * vol->reserved_pebs; | |
300 | ||
801c135c AB |
301 | if (add_mtd_device(mtd)) { |
302 | ubi_err("cannot not add MTD device\n"); | |
303 | kfree(mtd->name); | |
304 | return -ENFILE; | |
305 | } | |
306 | ||
307 | dbg_msg("added mtd%d (\"%s\"), size %u, EB size %u", | |
308 | mtd->index, mtd->name, mtd->size, mtd->erasesize); | |
309 | return 0; | |
310 | } | |
311 | ||
312 | /** | |
313 | * ubi_destroy_gluebi - close gluebi for an UBI volume. | |
314 | * @vol: volume description object | |
315 | * | |
316 | * This function is called when an UBI volume is removed in order to remove | |
317 | * corresponding fake MTD device. Returns zero in case of success and a | |
318 | * negative error code in case of failure. | |
319 | */ | |
320 | int ubi_destroy_gluebi(struct ubi_volume *vol) | |
321 | { | |
322 | int err; | |
323 | struct mtd_info *mtd = &vol->gluebi_mtd; | |
324 | ||
325 | dbg_msg("remove mtd%d", mtd->index); | |
326 | err = del_mtd_device(mtd); | |
327 | if (err) | |
328 | return err; | |
329 | kfree(mtd->name); | |
330 | return 0; | |
331 | } | |
941dfb07 AB |
332 | |
333 | /** | |
334 | * ubi_gluebi_updated - UBI volume was updated notifier. | |
335 | * @vol: volume description object | |
336 | * | |
337 | * This function is called every time an UBI volume is updated. This function | |
338 | * does nothing if volume @vol is dynamic, and changes MTD device size if the | |
339 | * volume is static. This is needed because static volumes cannot be read past | |
340 | * data they contain. | |
341 | */ | |
342 | void ubi_gluebi_updated(struct ubi_volume *vol) | |
343 | { | |
344 | struct mtd_info *mtd = &vol->gluebi_mtd; | |
345 | ||
346 | if (vol->vol_type == UBI_STATIC_VOLUME) | |
347 | mtd->size = vol->used_bytes; | |
348 | } |