blob: d397219238d3b8ede00b4075b1468c1922963d79 [file] [log] [blame]
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001/*
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 */
42static 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 */
84static 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 */
106static 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
Artem Bityutskiy89b96b62007-12-16 20:00:38 +0200132 err = ubi_eba_read_leb(ubi, vol, lnum, buf, offs, to_read, 0);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400133 if (err)
134 break;
135
136 lnum += 1;
137 offs = 0;
138 total_read -= to_read;
139 buf += to_read;
140 }
141
142 *retlen = len - total_read;
143 return err;
144}
145
146/**
147 * gluebi_write - write operation of emulated MTD devices.
148 * @mtd: MTD device description object
149 * @to: absolute offset where to write
150 * @len: how many bytes to write
151 * @retlen: count of written bytes is returned here
152 * @buf: buffer with data to write
153 *
154 * This function returns zero in case of success and a negative error code in
155 * case of failure.
156 */
157static int gluebi_write(struct mtd_info *mtd, loff_t to, size_t len,
158 size_t *retlen, const u_char *buf)
159{
160 int err = 0, lnum, offs, total_written;
161 struct ubi_volume *vol;
162 struct ubi_device *ubi;
163 uint64_t tmp = to;
164
165 dbg_msg("write %zd bytes to offset %lld", len, to);
166
167 if (len < 0 || to < 0 || len + to > mtd->size)
168 return -EINVAL;
169
170 vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
171 ubi = vol->ubi;
172
173 if (ubi->ro_mode)
174 return -EROFS;
175
176 offs = do_div(tmp, mtd->erasesize);
177 lnum = tmp;
178
179 if (len % mtd->writesize || offs % mtd->writesize)
180 return -EINVAL;
181
182 total_written = len;
183 while (total_written) {
184 size_t to_write = mtd->erasesize - offs;
185
186 if (to_write > total_written)
187 to_write = total_written;
188
Artem Bityutskiy89b96b62007-12-16 20:00:38 +0200189 err = ubi_eba_write_leb(ubi, vol, lnum, buf, offs, to_write,
190 UBI_UNKNOWN);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400191 if (err)
192 break;
193
194 lnum += 1;
195 offs = 0;
196 total_written -= to_write;
197 buf += to_write;
198 }
199
200 *retlen = len - total_written;
201 return err;
202}
203
204/**
205 * gluebi_erase - erase operation of emulated MTD devices.
206 * @mtd: the MTD device description object
207 * @instr: the erase operation description
208 *
209 * This function calls the erase callback when finishes. Returns zero in case
210 * of success and a negative error code in case of failure.
211 */
212static int gluebi_erase(struct mtd_info *mtd, struct erase_info *instr)
213{
214 int err, i, lnum, count;
215 struct ubi_volume *vol;
216 struct ubi_device *ubi;
217
218 dbg_msg("erase %u bytes at offset %u", instr->len, instr->addr);
219
220 if (instr->addr < 0 || instr->addr > mtd->size - mtd->erasesize)
221 return -EINVAL;
222
223 if (instr->len < 0 || instr->addr + instr->len > mtd->size)
224 return -EINVAL;
225
226 if (instr->addr % mtd->writesize || instr->len % mtd->writesize)
227 return -EINVAL;
228
229 lnum = instr->addr / mtd->erasesize;
230 count = instr->len / mtd->erasesize;
231
232 vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
233 ubi = vol->ubi;
234
235 if (ubi->ro_mode)
236 return -EROFS;
237
238 for (i = 0; i < count; i++) {
Artem Bityutskiy89b96b62007-12-16 20:00:38 +0200239 err = ubi_eba_unmap_leb(ubi, vol, lnum + i);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400240 if (err)
241 goto out_err;
242 }
243
244 /*
245 * MTD erase operations are synchronous, so we have to make sure the
246 * physical eraseblock is wiped out.
247 */
248 err = ubi_wl_flush(ubi);
249 if (err)
250 goto out_err;
251
252 instr->state = MTD_ERASE_DONE;
253 mtd_erase_callback(instr);
254 return 0;
255
256out_err:
257 instr->state = MTD_ERASE_FAILED;
258 instr->fail_addr = lnum * mtd->erasesize;
259 return err;
260}
261
262/**
263 * ubi_create_gluebi - initialize gluebi for an UBI volume.
264 * @ubi: UBI device description object
265 * @vol: volume description object
266 *
267 * This function is called when an UBI volume is created in order to create
268 * corresponding fake MTD device. Returns zero in case of success and a
269 * negative error code in case of failure.
270 */
271int ubi_create_gluebi(struct ubi_device *ubi, struct ubi_volume *vol)
272{
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400273 struct mtd_info *mtd = &vol->gluebi_mtd;
274
275 mtd->name = kmemdup(vol->name, vol->name_len + 1, GFP_KERNEL);
276 if (!mtd->name)
277 return -ENOMEM;
278
279 mtd->type = MTD_UBIVOLUME;
280 if (!ubi->ro_mode)
281 mtd->flags = MTD_WRITEABLE;
282 mtd->writesize = ubi->min_io_size;
283 mtd->owner = THIS_MODULE;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400284 mtd->erasesize = vol->usable_leb_size;
285 mtd->read = gluebi_read;
286 mtd->write = gluebi_write;
287 mtd->erase = gluebi_erase;
288 mtd->get_device = gluebi_get_device;
289 mtd->put_device = gluebi_put_device;
290
Artem Bityutskiy941dfb02007-05-05 16:33:13 +0300291 /*
292 * In case of dynamic volume, MTD device size is just volume size. In
293 * case of a static volume the size is equivalent to the amount of data
294 * bytes, which is zero at this moment and will be changed after volume
295 * update.
296 */
297 if (vol->vol_type == UBI_DYNAMIC_VOLUME)
298 mtd->size = vol->usable_leb_size * vol->reserved_pebs;
299
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400300 if (add_mtd_device(mtd)) {
301 ubi_err("cannot not add MTD device\n");
302 kfree(mtd->name);
303 return -ENFILE;
304 }
305
306 dbg_msg("added mtd%d (\"%s\"), size %u, EB size %u",
307 mtd->index, mtd->name, mtd->size, mtd->erasesize);
308 return 0;
309}
310
311/**
312 * ubi_destroy_gluebi - close gluebi for an UBI volume.
313 * @vol: volume description object
314 *
315 * This function is called when an UBI volume is removed in order to remove
316 * corresponding fake MTD device. Returns zero in case of success and a
317 * negative error code in case of failure.
318 */
319int ubi_destroy_gluebi(struct ubi_volume *vol)
320{
321 int err;
322 struct mtd_info *mtd = &vol->gluebi_mtd;
323
324 dbg_msg("remove mtd%d", mtd->index);
325 err = del_mtd_device(mtd);
326 if (err)
327 return err;
328 kfree(mtd->name);
329 return 0;
330}
Artem Bityutskiy941dfb02007-05-05 16:33:13 +0300331
332/**
333 * ubi_gluebi_updated - UBI volume was updated notifier.
334 * @vol: volume description object
335 *
336 * This function is called every time an UBI volume is updated. This function
337 * does nothing if volume @vol is dynamic, and changes MTD device size if the
338 * volume is static. This is needed because static volumes cannot be read past
339 * data they contain.
340 */
341void ubi_gluebi_updated(struct ubi_volume *vol)
342{
343 struct mtd_info *mtd = &vol->gluebi_mtd;
344
345 if (vol->vol_type == UBI_STATIC_VOLUME)
346 mtd->size = vol->used_bytes;
347}