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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/*
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#include <linux/major.h>
36
37
38struct mtdblk_dev {
39 struct mtd_blktrans_dev mbd;
40 int count;
41 struct mutex cache_mutex;
42 unsigned char *cache_data;
43 unsigned long cache_offset;
44 unsigned int cache_size;
45 enum { STATE_EMPTY, STATE_CLEAN, STATE_DIRTY } cache_state;
46};
47
48/*
49 * Cache stuff...
50 *
51 * Since typical flash erasable sectors are much larger than what Linux's
52 * buffer cache can handle, we must implement read-modify-write on flash
53 * sectors for each block write requests. To avoid over-erasing flash sectors
54 * and to speed things up, we locally cache a whole flash sector while it is
55 * being written to until a different sector is required.
56 */
57
58static void erase_callback(struct erase_info *done)
59{
60 wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
61 wake_up(wait_q);
62}
63
64static int erase_write (struct mtd_info *mtd, unsigned long pos,
65 int len, const char *buf)
66{
67 struct erase_info erase;
68 DECLARE_WAITQUEUE(wait, current);
69 wait_queue_head_t wait_q;
70 size_t retlen;
71 int ret;
72
73 /*
74 * First, let's erase the flash block.
75 */
76
77 init_waitqueue_head(&wait_q);
78 erase.mtd = mtd;
79 erase.callback = erase_callback;
80 erase.addr = pos;
81 erase.len = len;
82 erase.priv = (u_long)&wait_q;
83
84 set_current_state(TASK_INTERRUPTIBLE);
85 add_wait_queue(&wait_q, &wait);
86
87 ret = mtd_erase(mtd, &erase);
88 if (ret) {
89 set_current_state(TASK_RUNNING);
90 remove_wait_queue(&wait_q, &wait);
91 printk (KERN_WARNING "mtdblock: erase of region [0x%lx, 0x%x] "
92 "on \"%s\" failed\n",
93 pos, len, mtd->name);
94 return ret;
95 }
96
97 schedule(); /* Wait for erase to finish. */
98 remove_wait_queue(&wait_q, &wait);
99
100 /*
101 * Next, write the data to flash.
102 */
103
104 ret = mtd_write(mtd, pos, len, &retlen, buf);
105 if (ret)
106 return ret;
107 if (retlen != len)
108 return -EIO;
109 return 0;
110}
111
112
113static int write_cached_data (struct mtdblk_dev *mtdblk)
114{
115 struct mtd_info *mtd = mtdblk->mbd.mtd;
116 int ret;
117
118 if (mtdblk->cache_state != STATE_DIRTY)
119 return 0;
120
121 pr_debug("mtdblock: writing cached data for \"%s\" "
122 "at 0x%lx, size 0x%x\n", mtd->name,
123 mtdblk->cache_offset, mtdblk->cache_size);
124
125 ret = erase_write (mtd, mtdblk->cache_offset,
126 mtdblk->cache_size, mtdblk->cache_data);
127 if (ret)
128 return ret;
129
130 /*
131 * Here we could arguably set the cache state to STATE_CLEAN.
132 * However this could lead to inconsistency since we will not
133 * be notified if this content is altered on the flash by other
134 * means. Let's declare it empty and leave buffering tasks to
135 * the buffer cache instead.
136 */
137 mtdblk->cache_state = STATE_EMPTY;
138 return 0;
139}
140
141
142static int do_cached_write (struct mtdblk_dev *mtdblk, unsigned long pos,
143 int len, const char *buf)
144{
145 struct mtd_info *mtd = mtdblk->mbd.mtd;
146 unsigned int sect_size = mtdblk->cache_size;
147 size_t retlen;
148 int ret;
149
150 pr_debug("mtdblock: write on \"%s\" at 0x%lx, size 0x%x\n",
151 mtd->name, pos, len);
152
153 if (!sect_size)
154 return mtd_write(mtd, pos, len, &retlen, buf);
155
156 while (len > 0) {
157 unsigned long sect_start = (pos/sect_size)*sect_size;
158 unsigned int offset = pos - sect_start;
159 unsigned int size = sect_size - offset;
160 if( size > len )
161 size = len;
162
163 if (size == sect_size) {
164 /*
165 * We are covering a whole sector. Thus there is no
166 * need to bother with the cache while it may still be
167 * useful for other partial writes.
168 */
169 ret = erase_write (mtd, pos, size, buf);
170 if (ret)
171 return ret;
172 } else {
173 /* Partial sector: need to use the cache */
174
175 if (mtdblk->cache_state == STATE_DIRTY &&
176 mtdblk->cache_offset != sect_start) {
177 ret = write_cached_data(mtdblk);
178 if (ret)
179 return ret;
180 }
181
182 if (mtdblk->cache_state == STATE_EMPTY ||
183 mtdblk->cache_offset != sect_start) {
184 /* fill the cache with the current sector */
185 mtdblk->cache_state = STATE_EMPTY;
186 ret = mtd_read(mtd, sect_start, sect_size,
187 &retlen, mtdblk->cache_data);
188 if (ret)
189 return ret;
190 if (retlen != sect_size)
191 return -EIO;
192
193 mtdblk->cache_offset = sect_start;
194 mtdblk->cache_size = sect_size;
195 mtdblk->cache_state = STATE_CLEAN;
196 }
197
198 /* write data to our local cache */
199 memcpy (mtdblk->cache_data + offset, buf, size);
200 mtdblk->cache_state = STATE_DIRTY;
201 }
202
203 buf += size;
204 pos += size;
205 len -= size;
206 }
207
208 return 0;
209}
210
211
212static int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos,
213 int len, char *buf)
214{
215 struct mtd_info *mtd = mtdblk->mbd.mtd;
216 unsigned int sect_size = mtdblk->cache_size;
217 size_t retlen;
218 int ret;
219
220 pr_debug("mtdblock: read on \"%s\" at 0x%lx, size 0x%x\n",
221 mtd->name, pos, len);
222
223 if (!sect_size)
224 return mtd_read(mtd, pos, len, &retlen, buf);
225
226 while (len > 0) {
227 unsigned long sect_start = (pos/sect_size)*sect_size;
228 unsigned int offset = pos - sect_start;
229 unsigned int size = sect_size - offset;
230 if (size > len)
231 size = len;
232
233 /*
234 * Check if the requested data is already cached
235 * Read the requested amount of data from our internal cache if it
236 * contains what we want, otherwise we read the data directly
237 * from flash.
238 */
239 if (mtdblk->cache_state != STATE_EMPTY &&
240 mtdblk->cache_offset == sect_start) {
241 memcpy (buf, mtdblk->cache_data + offset, size);
242 } else {
243 ret = mtd_read(mtd, pos, size, &retlen, buf);
244 if (ret)
245 return ret;
246 if (retlen != size)
247 return -EIO;
248 }
249
250 buf += size;
251 pos += size;
252 len -= size;
253 }
254
255 return 0;
256}
257
258static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
259 unsigned long block, char *buf)
260{
261 struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
262 return do_cached_read(mtdblk, block<<9, 512, buf);
263}
264
265static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
266 unsigned long block, char *buf)
267{
268 struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
269 if (unlikely(!mtdblk->cache_data && mtdblk->cache_size)) {
270 mtdblk->cache_data = vmalloc(mtdblk->mbd.mtd->erasesize);
271 if (!mtdblk->cache_data)
272 return -EINTR;
273 /* -EINTR is not really correct, but it is the best match
274 * documented in man 2 write for all cases. We could also
275 * return -EAGAIN sometimes, but why bother?
276 */
277 }
278 return do_cached_write(mtdblk, block<<9, 512, buf);
279}
280
281static int mtdblock_open(struct mtd_blktrans_dev *mbd)
282{
283 struct mtdblk_dev *mtdblk = container_of(mbd, struct mtdblk_dev, mbd);
284
285 pr_debug("mtdblock_open\n");
286
287 if (mtdblk->count) {
288 mtdblk->count++;
289 return 0;
290 }
291
292 /* OK, it's not open. Create cache info for it */
293 mtdblk->count = 1;
294 mutex_init(&mtdblk->cache_mutex);
295 mtdblk->cache_state = STATE_EMPTY;
296 if (!(mbd->mtd->flags & MTD_NO_ERASE) && mbd->mtd->erasesize) {
297 mtdblk->cache_size = mbd->mtd->erasesize;
298 mtdblk->cache_data = NULL;
299 }
300
301 pr_debug("ok\n");
302
303 return 0;
304}
305
306static void mtdblock_release(struct mtd_blktrans_dev *mbd)
307{
308 struct mtdblk_dev *mtdblk = container_of(mbd, struct mtdblk_dev, mbd);
309
310 pr_debug("mtdblock_release\n");
311
312 mutex_lock(&mtdblk->cache_mutex);
313 write_cached_data(mtdblk);
314 mutex_unlock(&mtdblk->cache_mutex);
315
316 if (!--mtdblk->count) {
317 /*
318 * It was the last usage. Free the cache, but only sync if
319 * opened for writing.
320 */
321 if (mbd->file_mode & FMODE_WRITE)
322 mtd_sync(mbd->mtd);
323 vfree(mtdblk->cache_data);
324 }
325
326 pr_debug("ok\n");
327}
328
329static int mtdblock_flush(struct mtd_blktrans_dev *dev)
330{
331 struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
332
333 mutex_lock(&mtdblk->cache_mutex);
334 write_cached_data(mtdblk);
335 mutex_unlock(&mtdblk->cache_mutex);
336 mtd_sync(dev->mtd);
337 return 0;
338}
339
340static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
341{
342 struct mtdblk_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);
343
344 if (!dev)
345 return;
346
347 dev->mbd.mtd = mtd;
348 dev->mbd.devnum = mtd->index;
349
350 dev->mbd.size = mtd->size >> 9;
351 dev->mbd.tr = tr;
352
353 if (!(mtd->flags & MTD_WRITEABLE))
354 dev->mbd.readonly = 1;
355
356 if (add_mtd_blktrans_dev(&dev->mbd))
357 kfree(dev);
358}
359
360static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
361{
362 del_mtd_blktrans_dev(dev);
363}
364
365static struct mtd_blktrans_ops mtdblock_tr = {
366 .name = "mtdblock",
367 .major = MTD_BLOCK_MAJOR,
368 .part_bits = 0,
369 .blksize = 512,
370 .open = mtdblock_open,
371 .flush = mtdblock_flush,
372 .release = mtdblock_release,
373 .readsect = mtdblock_readsect,
374 .writesect = mtdblock_writesect,
375 .add_mtd = mtdblock_add_mtd,
376 .remove_dev = mtdblock_remove_dev,
377 .owner = THIS_MODULE,
378};
379
380static int __init init_mtdblock(void)
381{
382 return register_mtd_blktrans(&mtdblock_tr);
383}
384
385static void __exit cleanup_mtdblock(void)
386{
387 deregister_mtd_blktrans(&mtdblock_tr);
388}
389
390module_init(init_mtdblock);
391module_exit(cleanup_mtdblock);
392
393
394MODULE_LICENSE("GPL");
395MODULE_AUTHOR("Nicolas Pitre <nico@fluxnic.net> et al.");
396MODULE_DESCRIPTION("Caching read/erase/writeback block device emulation access to MTD devices");