blob: c8bbfd1e67aba3f33c346873f5c2c928411464bb [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
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 */
158static 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 */
213static 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
257out_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 */
272int ubi_create_gluebi(struct ubi_device *ubi, struct ubi_volume *vol)
273{
274 int err;
275 struct mtd_info *mtd = &vol->gluebi_mtd;
276
277 mtd->name = kmemdup(vol->name, vol->name_len + 1, GFP_KERNEL);
278 if (!mtd->name)
279 return -ENOMEM;
280
281 mtd->type = MTD_UBIVOLUME;
282 if (!ubi->ro_mode)
283 mtd->flags = MTD_WRITEABLE;
284 mtd->writesize = ubi->min_io_size;
285 mtd->owner = THIS_MODULE;
286 mtd->size = vol->usable_leb_size * vol->reserved_pebs;
287 mtd->erasesize = vol->usable_leb_size;
288 mtd->read = gluebi_read;
289 mtd->write = gluebi_write;
290 mtd->erase = gluebi_erase;
291 mtd->get_device = gluebi_get_device;
292 mtd->put_device = gluebi_put_device;
293
294 if (add_mtd_device(mtd)) {
295 ubi_err("cannot not add MTD device\n");
296 kfree(mtd->name);
297 return -ENFILE;
298 }
299
300 dbg_msg("added mtd%d (\"%s\"), size %u, EB size %u",
301 mtd->index, mtd->name, mtd->size, mtd->erasesize);
302 return 0;
303}
304
305/**
306 * ubi_destroy_gluebi - close gluebi for an UBI volume.
307 * @vol: volume description object
308 *
309 * This function is called when an UBI volume is removed in order to remove
310 * corresponding fake MTD device. Returns zero in case of success and a
311 * negative error code in case of failure.
312 */
313int ubi_destroy_gluebi(struct ubi_volume *vol)
314{
315 int err;
316 struct mtd_info *mtd = &vol->gluebi_mtd;
317
318 dbg_msg("remove mtd%d", mtd->index);
319 err = del_mtd_device(mtd);
320 if (err)
321 return err;
322 kfree(mtd->name);
323 return 0;
324}