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1/*
2 * Direct MTD block device access
3 *
4 * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
5 * Copyright © 2000-2003 Nicolas Pitre <nico@fluxnic.net>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 *
21 */
22
23#include <linux/fs.h>
24#include <linux/init.h>
25#include <linux/kernel.h>
26#include <linux/module.h>
27#include <linux/sched.h>
28#include <linux/slab.h>
29#include <linux/types.h>
30#include <linux/vmalloc.h>
31
32#include <linux/mtd/mtd.h>
33#include <linux/mtd/blktrans.h>
34#include <linux/mutex.h>
35
36
37struct mtdblk_dev {
38 struct mtd_blktrans_dev mbd;
39 int count;
40 struct mutex cache_mutex;
41 unsigned char *cache_data;
42 unsigned long cache_offset;
43 unsigned int cache_size;
44 enum { STATE_EMPTY, STATE_CLEAN, STATE_DIRTY } cache_state;
45};
46
47static struct mutex mtdblks_lock;
48
49/*
50 * Cache stuff...
51 *
52 * Since typical flash erasable sectors are much larger than what Linux's
53 * buffer cache can handle, we must implement read-modify-write on flash
54 * sectors for each block write requests. To avoid over-erasing flash sectors
55 * and to speed things up, we locally cache a whole flash sector while it is
56 * being written to until a different sector is required.
57 */
58
59static void erase_callback(struct erase_info *done)
60{
61 wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
62 wake_up(wait_q);
63}
64
65static int erase_write (struct mtd_info *mtd, unsigned long pos,
66 int len, const char *buf)
67{
68 struct erase_info erase;
69 DECLARE_WAITQUEUE(wait, current);
70 wait_queue_head_t wait_q;
71 size_t retlen;
72 int ret;
73
74 /*
75 * First, let's erase the flash block.
76 */
77
78 init_waitqueue_head(&wait_q);
79 erase.mtd = mtd;
80 erase.callback = erase_callback;
81 erase.addr = pos;
82 erase.len = len;
83 erase.priv = (u_long)&wait_q;
84
85 set_current_state(TASK_INTERRUPTIBLE);
86 add_wait_queue(&wait_q, &wait);
87
88 ret = mtd->erase(mtd, &erase);
89 if (ret) {
90 set_current_state(TASK_RUNNING);
91 remove_wait_queue(&wait_q, &wait);
92 printk (KERN_WARNING "mtdblock: erase of region [0x%lx, 0x%x] "
93 "on \"%s\" failed\n",
94 pos, len, mtd->name);
95 return ret;
96 }
97
98 schedule(); /* Wait for erase to finish. */
99 remove_wait_queue(&wait_q, &wait);
100
101 /*
102 * Next, write the data to flash.
103 */
104
105 ret = mtd->write(mtd, pos, len, &retlen, buf);
106 if (ret)
107 return ret;
108 if (retlen != len)
109 return -EIO;
110 return 0;
111}
112
113
114static int write_cached_data (struct mtdblk_dev *mtdblk)
115{
116 struct mtd_info *mtd = mtdblk->mbd.mtd;
117 int ret;
118
119 if (mtdblk->cache_state != STATE_DIRTY)
120 return 0;
121
122 DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: writing cached data for \"%s\" "
123 "at 0x%lx, size 0x%x\n", mtd->name,
124 mtdblk->cache_offset, mtdblk->cache_size);
125
126 ret = erase_write (mtd, mtdblk->cache_offset,
127 mtdblk->cache_size, mtdblk->cache_data);
128 if (ret)
129 return ret;
130
131 /*
132 * Here we could arguably set the cache state to STATE_CLEAN.
133 * However this could lead to inconsistency since we will not
134 * be notified if this content is altered on the flash by other
135 * means. Let's declare it empty and leave buffering tasks to
136 * the buffer cache instead.
137 */
138 mtdblk->cache_state = STATE_EMPTY;
139 return 0;
140}
141
142
143static int do_cached_write (struct mtdblk_dev *mtdblk, unsigned long pos,
144 int len, const char *buf)
145{
146 struct mtd_info *mtd = mtdblk->mbd.mtd;
147 unsigned int sect_size = mtdblk->cache_size;
148 size_t retlen;
149 int ret;
150
151 DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: write on \"%s\" at 0x%lx, size 0x%x\n",
152 mtd->name, pos, len);
153
154 if (!sect_size)
155 return mtd->write(mtd, pos, len, &retlen, buf);
156
157 while (len > 0) {
158 unsigned long sect_start = (pos/sect_size)*sect_size;
159 unsigned int offset = pos - sect_start;
160 unsigned int size = sect_size - offset;
161 if( size > len )
162 size = len;
163
164 if (size == sect_size) {
165 /*
166 * We are covering a whole sector. Thus there is no
167 * need to bother with the cache while it may still be
168 * useful for other partial writes.
169 */
170 ret = erase_write (mtd, pos, size, buf);
171 if (ret)
172 return ret;
173 } else {
174 /* Partial sector: need to use the cache */
175
176 if (mtdblk->cache_state == STATE_DIRTY &&
177 mtdblk->cache_offset != sect_start) {
178 ret = write_cached_data(mtdblk);
179 if (ret)
180 return ret;
181 }
182
183 if (mtdblk->cache_state == STATE_EMPTY ||
184 mtdblk->cache_offset != sect_start) {
185 /* fill the cache with the current sector */
186 mtdblk->cache_state = STATE_EMPTY;
187 ret = mtd->read(mtd, sect_start, sect_size,
188 &retlen, mtdblk->cache_data);
189 if (ret)
190 return ret;
191 if (retlen != sect_size)
192 return -EIO;
193
194 mtdblk->cache_offset = sect_start;
195 mtdblk->cache_size = sect_size;
196 mtdblk->cache_state = STATE_CLEAN;
197 }
198
199 /* write data to our local cache */
200 memcpy (mtdblk->cache_data + offset, buf, size);
201 mtdblk->cache_state = STATE_DIRTY;
202 }
203
204 buf += size;
205 pos += size;
206 len -= size;
207 }
208
209 return 0;
210}
211
212
213static int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos,
214 int len, char *buf)
215{
216 struct mtd_info *mtd = mtdblk->mbd.mtd;
217 unsigned int sect_size = mtdblk->cache_size;
218 size_t retlen;
219 int ret;
220
221 DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: read on \"%s\" at 0x%lx, size 0x%x\n",
222 mtd->name, pos, len);
223
224 if (!sect_size)
225 return mtd->read(mtd, pos, len, &retlen, buf);
226
227 while (len > 0) {
228 unsigned long sect_start = (pos/sect_size)*sect_size;
229 unsigned int offset = pos - sect_start;
230 unsigned int size = sect_size - offset;
231 if (size > len)
232 size = len;
233
234 /*
235 * Check if the requested data is already cached
236 * Read the requested amount of data from our internal cache if it
237 * contains what we want, otherwise we read the data directly
238 * from flash.
239 */
240 if (mtdblk->cache_state != STATE_EMPTY &&
241 mtdblk->cache_offset == sect_start) {
242 memcpy (buf, mtdblk->cache_data + offset, size);
243 } else {
244 ret = mtd->read(mtd, pos, size, &retlen, buf);
245 if (ret)
246 return ret;
247 if (retlen != size)
248 return -EIO;
249 }
250
251 buf += size;
252 pos += size;
253 len -= size;
254 }
255
256 return 0;
257}
258
259static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
260 unsigned long block, char *buf)
261{
262 struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
263 return do_cached_read(mtdblk, block<<9, 512, buf);
264}
265
266static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
267 unsigned long block, char *buf)
268{
269 struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
270 if (unlikely(!mtdblk->cache_data && mtdblk->cache_size)) {
271 mtdblk->cache_data = vmalloc(mtdblk->mbd.mtd->erasesize);
272 if (!mtdblk->cache_data)
273 return -EINTR;
274 /* -EINTR is not really correct, but it is the best match
275 * documented in man 2 write for all cases. We could also
276 * return -EAGAIN sometimes, but why bother?
277 */
278 }
279 return do_cached_write(mtdblk, block<<9, 512, buf);
280}
281
282static int mtdblock_open(struct mtd_blktrans_dev *mbd)
283{
284 struct mtdblk_dev *mtdblk = container_of(mbd, struct mtdblk_dev, mbd);
285
286 DEBUG(MTD_DEBUG_LEVEL1,"mtdblock_open\n");
287
288 mutex_lock(&mtdblks_lock);
289 if (mtdblk->count) {
290 mtdblk->count++;
291 mutex_unlock(&mtdblks_lock);
292 return 0;
293 }
294
295 /* OK, it's not open. Create cache info for it */
296 mtdblk->count = 1;
297 mutex_init(&mtdblk->cache_mutex);
298 mtdblk->cache_state = STATE_EMPTY;
299 if (!(mbd->mtd->flags & MTD_NO_ERASE) && mbd->mtd->erasesize) {
300 mtdblk->cache_size = mbd->mtd->erasesize;
301 mtdblk->cache_data = NULL;
302 }
303
304 mutex_unlock(&mtdblks_lock);
305
306 DEBUG(MTD_DEBUG_LEVEL1, "ok\n");
307
308 return 0;
309}
310
311static int mtdblock_release(struct mtd_blktrans_dev *mbd)
312{
313 struct mtdblk_dev *mtdblk = container_of(mbd, struct mtdblk_dev, mbd);
314
315 DEBUG(MTD_DEBUG_LEVEL1, "mtdblock_release\n");
316
317 mutex_lock(&mtdblks_lock);
318
319 mutex_lock(&mtdblk->cache_mutex);
320 write_cached_data(mtdblk);
321 mutex_unlock(&mtdblk->cache_mutex);
322
323 if (!--mtdblk->count) {
324 /* It was the last usage. Free the cache */
325 if (mbd->mtd->sync)
326 mbd->mtd->sync(mbd->mtd);
327 vfree(mtdblk->cache_data);
328 }
329
330 mutex_unlock(&mtdblks_lock);
331
332 DEBUG(MTD_DEBUG_LEVEL1, "ok\n");
333
334 return 0;
335}
336
337static int mtdblock_flush(struct mtd_blktrans_dev *dev)
338{
339 struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
340
341 mutex_lock(&mtdblk->cache_mutex);
342 write_cached_data(mtdblk);
343 mutex_unlock(&mtdblk->cache_mutex);
344
345 if (dev->mtd->sync)
346 dev->mtd->sync(dev->mtd);
347 return 0;
348}
349
350static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
351{
352 struct mtdblk_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);
353
354 if (!dev)
355 return;
356
357 dev->mbd.mtd = mtd;
358 dev->mbd.devnum = mtd->index;
359
360 dev->mbd.size = mtd->size >> 9;
361 dev->mbd.tr = tr;
362
363 if (!(mtd->flags & MTD_WRITEABLE))
364 dev->mbd.readonly = 1;
365
366 if (add_mtd_blktrans_dev(&dev->mbd))
367 kfree(dev);
368}
369
370static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
371{
372 del_mtd_blktrans_dev(dev);
373}
374
375static struct mtd_blktrans_ops mtdblock_tr = {
376 .name = "mtdblock",
377 .major = 31,
378 .part_bits = 0,
379 .blksize = 512,
380 .open = mtdblock_open,
381 .flush = mtdblock_flush,
382 .release = mtdblock_release,
383 .readsect = mtdblock_readsect,
384 .writesect = mtdblock_writesect,
385 .add_mtd = mtdblock_add_mtd,
386 .remove_dev = mtdblock_remove_dev,
387 .owner = THIS_MODULE,
388};
389
390static int __init init_mtdblock(void)
391{
392 mutex_init(&mtdblks_lock);
393
394 return register_mtd_blktrans(&mtdblock_tr);
395}
396
397static void __exit cleanup_mtdblock(void)
398{
399 deregister_mtd_blktrans(&mtdblock_tr);
400}
401
402module_init(init_mtdblock);
403module_exit(cleanup_mtdblock);
404
405
406MODULE_LICENSE("GPL");
407MODULE_AUTHOR("Nicolas Pitre <nico@fluxnic.net> et al.");
408MODULE_DESCRIPTION("Caching read/erase/writeback block device emulation access to MTD devices");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Direct MTD block device access
4 *
5 * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
6 * Copyright © 2000-2003 Nicolas Pitre <nico@fluxnic.net>
7 */
8
9#include <linux/fs.h>
10#include <linux/init.h>
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/sched.h>
14#include <linux/slab.h>
15#include <linux/types.h>
16#include <linux/vmalloc.h>
17
18#include <linux/mtd/mtd.h>
19#include <linux/mtd/blktrans.h>
20#include <linux/mutex.h>
21#include <linux/major.h>
22
23
24struct mtdblk_dev {
25 struct mtd_blktrans_dev mbd;
26 int count;
27 struct mutex cache_mutex;
28 unsigned char *cache_data;
29 unsigned long cache_offset;
30 unsigned int cache_size;
31 enum { STATE_EMPTY, STATE_CLEAN, STATE_DIRTY } cache_state;
32};
33
34/*
35 * Cache stuff...
36 *
37 * Since typical flash erasable sectors are much larger than what Linux's
38 * buffer cache can handle, we must implement read-modify-write on flash
39 * sectors for each block write requests. To avoid over-erasing flash sectors
40 * and to speed things up, we locally cache a whole flash sector while it is
41 * being written to until a different sector is required.
42 */
43
44static int erase_write (struct mtd_info *mtd, unsigned long pos,
45 unsigned int len, const char *buf)
46{
47 struct erase_info erase;
48 size_t retlen;
49 int ret;
50
51 /*
52 * First, let's erase the flash block.
53 */
54 erase.addr = pos;
55 erase.len = len;
56
57 ret = mtd_erase(mtd, &erase);
58 if (ret) {
59 printk (KERN_WARNING "mtdblock: erase of region [0x%lx, 0x%x] "
60 "on \"%s\" failed\n",
61 pos, len, mtd->name);
62 return ret;
63 }
64
65 /*
66 * Next, write the data to flash.
67 */
68
69 ret = mtd_write(mtd, pos, len, &retlen, buf);
70 if (ret)
71 return ret;
72 if (retlen != len)
73 return -EIO;
74 return 0;
75}
76
77
78static int write_cached_data (struct mtdblk_dev *mtdblk)
79{
80 struct mtd_info *mtd = mtdblk->mbd.mtd;
81 int ret;
82
83 if (mtdblk->cache_state != STATE_DIRTY)
84 return 0;
85
86 pr_debug("mtdblock: writing cached data for \"%s\" "
87 "at 0x%lx, size 0x%x\n", mtd->name,
88 mtdblk->cache_offset, mtdblk->cache_size);
89
90 ret = erase_write (mtd, mtdblk->cache_offset,
91 mtdblk->cache_size, mtdblk->cache_data);
92
93 /*
94 * Here we could arguably set the cache state to STATE_CLEAN.
95 * However this could lead to inconsistency since we will not
96 * be notified if this content is altered on the flash by other
97 * means. Let's declare it empty and leave buffering tasks to
98 * the buffer cache instead.
99 *
100 * If this cache_offset points to a bad block, data cannot be
101 * written to the device. Clear cache_state to avoid writing to
102 * bad blocks repeatedly.
103 */
104 if (ret == 0 || ret == -EIO)
105 mtdblk->cache_state = STATE_EMPTY;
106 return ret;
107}
108
109
110static int do_cached_write (struct mtdblk_dev *mtdblk, unsigned long pos,
111 int len, const char *buf)
112{
113 struct mtd_info *mtd = mtdblk->mbd.mtd;
114 unsigned int sect_size = mtdblk->cache_size;
115 size_t retlen;
116 int ret;
117
118 pr_debug("mtdblock: write on \"%s\" at 0x%lx, size 0x%x\n",
119 mtd->name, pos, len);
120
121 if (!sect_size)
122 return mtd_write(mtd, pos, len, &retlen, buf);
123
124 while (len > 0) {
125 unsigned long sect_start = (pos/sect_size)*sect_size;
126 unsigned int offset = pos - sect_start;
127 unsigned int size = sect_size - offset;
128 if( size > len )
129 size = len;
130
131 if (size == sect_size) {
132 /*
133 * We are covering a whole sector. Thus there is no
134 * need to bother with the cache while it may still be
135 * useful for other partial writes.
136 */
137 ret = erase_write (mtd, pos, size, buf);
138 if (ret)
139 return ret;
140 } else {
141 /* Partial sector: need to use the cache */
142
143 if (mtdblk->cache_state == STATE_DIRTY &&
144 mtdblk->cache_offset != sect_start) {
145 ret = write_cached_data(mtdblk);
146 if (ret)
147 return ret;
148 }
149
150 if (mtdblk->cache_state == STATE_EMPTY ||
151 mtdblk->cache_offset != sect_start) {
152 /* fill the cache with the current sector */
153 mtdblk->cache_state = STATE_EMPTY;
154 ret = mtd_read(mtd, sect_start, sect_size,
155 &retlen, mtdblk->cache_data);
156 if (ret)
157 return ret;
158 if (retlen != sect_size)
159 return -EIO;
160
161 mtdblk->cache_offset = sect_start;
162 mtdblk->cache_size = sect_size;
163 mtdblk->cache_state = STATE_CLEAN;
164 }
165
166 /* write data to our local cache */
167 memcpy (mtdblk->cache_data + offset, buf, size);
168 mtdblk->cache_state = STATE_DIRTY;
169 }
170
171 buf += size;
172 pos += size;
173 len -= size;
174 }
175
176 return 0;
177}
178
179
180static int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos,
181 int len, char *buf)
182{
183 struct mtd_info *mtd = mtdblk->mbd.mtd;
184 unsigned int sect_size = mtdblk->cache_size;
185 size_t retlen;
186 int ret;
187
188 pr_debug("mtdblock: read on \"%s\" at 0x%lx, size 0x%x\n",
189 mtd->name, pos, len);
190
191 if (!sect_size)
192 return mtd_read(mtd, pos, len, &retlen, buf);
193
194 while (len > 0) {
195 unsigned long sect_start = (pos/sect_size)*sect_size;
196 unsigned int offset = pos - sect_start;
197 unsigned int size = sect_size - offset;
198 if (size > len)
199 size = len;
200
201 /*
202 * Check if the requested data is already cached
203 * Read the requested amount of data from our internal cache if it
204 * contains what we want, otherwise we read the data directly
205 * from flash.
206 */
207 if (mtdblk->cache_state != STATE_EMPTY &&
208 mtdblk->cache_offset == sect_start) {
209 memcpy (buf, mtdblk->cache_data + offset, size);
210 } else {
211 ret = mtd_read(mtd, pos, size, &retlen, buf);
212 if (ret)
213 return ret;
214 if (retlen != size)
215 return -EIO;
216 }
217
218 buf += size;
219 pos += size;
220 len -= size;
221 }
222
223 return 0;
224}
225
226static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
227 unsigned long block, char *buf)
228{
229 struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
230 return do_cached_read(mtdblk, block<<9, 512, buf);
231}
232
233static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
234 unsigned long block, char *buf)
235{
236 struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
237 if (unlikely(!mtdblk->cache_data && mtdblk->cache_size)) {
238 mtdblk->cache_data = vmalloc(mtdblk->mbd.mtd->erasesize);
239 if (!mtdblk->cache_data)
240 return -EINTR;
241 /* -EINTR is not really correct, but it is the best match
242 * documented in man 2 write for all cases. We could also
243 * return -EAGAIN sometimes, but why bother?
244 */
245 }
246 return do_cached_write(mtdblk, block<<9, 512, buf);
247}
248
249static int mtdblock_open(struct mtd_blktrans_dev *mbd)
250{
251 struct mtdblk_dev *mtdblk = container_of(mbd, struct mtdblk_dev, mbd);
252
253 pr_debug("mtdblock_open\n");
254
255 if (mtdblk->count) {
256 mtdblk->count++;
257 return 0;
258 }
259
260 /* OK, it's not open. Create cache info for it */
261 mtdblk->count = 1;
262 mutex_init(&mtdblk->cache_mutex);
263 mtdblk->cache_state = STATE_EMPTY;
264 if (!(mbd->mtd->flags & MTD_NO_ERASE) && mbd->mtd->erasesize) {
265 mtdblk->cache_size = mbd->mtd->erasesize;
266 mtdblk->cache_data = NULL;
267 }
268
269 pr_debug("ok\n");
270
271 return 0;
272}
273
274static void mtdblock_release(struct mtd_blktrans_dev *mbd)
275{
276 struct mtdblk_dev *mtdblk = container_of(mbd, struct mtdblk_dev, mbd);
277
278 pr_debug("mtdblock_release\n");
279
280 mutex_lock(&mtdblk->cache_mutex);
281 write_cached_data(mtdblk);
282 mutex_unlock(&mtdblk->cache_mutex);
283
284 if (!--mtdblk->count) {
285 /*
286 * It was the last usage. Free the cache, but only sync if
287 * opened for writing.
288 */
289 if (mbd->file_mode & FMODE_WRITE)
290 mtd_sync(mbd->mtd);
291 vfree(mtdblk->cache_data);
292 }
293
294 pr_debug("ok\n");
295}
296
297static int mtdblock_flush(struct mtd_blktrans_dev *dev)
298{
299 struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
300 int ret;
301
302 mutex_lock(&mtdblk->cache_mutex);
303 ret = write_cached_data(mtdblk);
304 mutex_unlock(&mtdblk->cache_mutex);
305 mtd_sync(dev->mtd);
306 return ret;
307}
308
309static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
310{
311 struct mtdblk_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);
312
313 if (!dev)
314 return;
315
316 dev->mbd.mtd = mtd;
317 dev->mbd.devnum = mtd->index;
318
319 dev->mbd.size = mtd->size >> 9;
320 dev->mbd.tr = tr;
321
322 if (!(mtd->flags & MTD_WRITEABLE))
323 dev->mbd.readonly = 1;
324
325 if (add_mtd_blktrans_dev(&dev->mbd))
326 kfree(dev);
327}
328
329static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
330{
331 del_mtd_blktrans_dev(dev);
332}
333
334static struct mtd_blktrans_ops mtdblock_tr = {
335 .name = "mtdblock",
336 .major = MTD_BLOCK_MAJOR,
337 .part_bits = 0,
338 .blksize = 512,
339 .open = mtdblock_open,
340 .flush = mtdblock_flush,
341 .release = mtdblock_release,
342 .readsect = mtdblock_readsect,
343 .writesect = mtdblock_writesect,
344 .add_mtd = mtdblock_add_mtd,
345 .remove_dev = mtdblock_remove_dev,
346 .owner = THIS_MODULE,
347};
348
349static int __init init_mtdblock(void)
350{
351 return register_mtd_blktrans(&mtdblock_tr);
352}
353
354static void __exit cleanup_mtdblock(void)
355{
356 deregister_mtd_blktrans(&mtdblock_tr);
357}
358
359module_init(init_mtdblock);
360module_exit(cleanup_mtdblock);
361
362
363MODULE_LICENSE("GPL");
364MODULE_AUTHOR("Nicolas Pitre <nico@fluxnic.net> et al.");
365MODULE_DESCRIPTION("Caching read/erase/writeback block device emulation access to MTD devices");