[deliverable/linux.git] / drivers / mtd / mtdblock.c

/* 
 * Direct MTD block device access
 *
 * $Id: mtdblock.c,v 1.66 2004/11/25 13:52:52 joern Exp $
 *
 * (C) 2000-2003 Nicolas Pitre <nico@cam.org>
 * (C) 1999-2003 David Woodhouse <dwmw2@infradead.org>
 */

#include <linux/config.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/sched.h>	/* TASK_* */
#include <linux/mtd/mtd.h>
#include <linux/mtd/blktrans.h>

static struct mtdblk_dev {
	struct mtd_info *mtd;
	int count;
	struct semaphore cache_sem;
	unsigned char *cache_data;
	unsigned long cache_offset;
	unsigned int cache_size;
	enum { STATE_EMPTY, STATE_CLEAN, STATE_DIRTY } cache_state;
} *mtdblks[MAX_MTD_DEVICES];

/*
 * Cache stuff...
 * 
 * Since typical flash erasable sectors are much larger than what Linux's
 * buffer cache can handle, we must implement read-modify-write on flash
 * sectors for each block write requests.  To avoid over-erasing flash sectors
 * and to speed things up, we locally cache a whole flash sector while it is
 * being written to until a different sector is required.
 */

static void erase_callback(struct erase_info *done)
{
	wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
	wake_up(wait_q);
}

static int erase_write (struct mtd_info *mtd, unsigned long pos, 
			int len, const char *buf)
{
	struct erase_info erase;
	DECLARE_WAITQUEUE(wait, current);
	wait_queue_head_t wait_q;
	size_t retlen;
	int ret;

	/*
	 * First, let's erase the flash block.
	 */

	init_waitqueue_head(&wait_q);
	erase.mtd = mtd;
	erase.callback = erase_callback;
	erase.addr = pos;
	erase.len = len;
	erase.priv = (u_long)&wait_q;

	set_current_state(TASK_INTERRUPTIBLE);
	add_wait_queue(&wait_q, &wait);

	ret = MTD_ERASE(mtd, &erase);
	if (ret) {
		set_current_state(TASK_RUNNING);
		remove_wait_queue(&wait_q, &wait);
		printk (KERN_WARNING "mtdblock: erase of region [0x%lx, 0x%x] "
				     "on \"%s\" failed\n",
			pos, len, mtd->name);
		return ret;
	}

	schedule();  /* Wait for erase to finish. */
	remove_wait_queue(&wait_q, &wait);

	/*
	 * Next, writhe data to flash.
	 */

	ret = MTD_WRITE (mtd, pos, len, &retlen, buf);
	if (ret)
		return ret;
	if (retlen != len)
		return -EIO;
	return 0;
}


static int write_cached_data (struct mtdblk_dev *mtdblk)
{
	struct mtd_info *mtd = mtdblk->mtd;
	int ret;

	if (mtdblk->cache_state != STATE_DIRTY)
		return 0;

	DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: writing cached data for \"%s\" "
			"at 0x%lx, size 0x%x\n", mtd->name, 
			mtdblk->cache_offset, mtdblk->cache_size);
	
	ret = erase_write (mtd, mtdblk->cache_offset, 
			   mtdblk->cache_size, mtdblk->cache_data);
	if (ret)
		return ret;

	/*
	 * Here we could argubly set the cache state to STATE_CLEAN.
	 * However this could lead to inconsistency since we will not 
	 * be notified if this content is altered on the flash by other 
	 * means.  Let's declare it empty and leave buffering tasks to
	 * the buffer cache instead.
	 */
	mtdblk->cache_state = STATE_EMPTY;
	return 0;
}


static int do_cached_write (struct mtdblk_dev *mtdblk, unsigned long pos, 
			    int len, const char *buf)
{
	struct mtd_info *mtd = mtdblk->mtd;
	unsigned int sect_size = mtdblk->cache_size;
	size_t retlen;
	int ret;

	DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: write on \"%s\" at 0x%lx, size 0x%x\n",
		mtd->name, pos, len);
	
	if (!sect_size)
		return MTD_WRITE (mtd, pos, len, &retlen, buf);

	while (len > 0) {
		unsigned long sect_start = (pos/sect_size)*sect_size;
		unsigned int offset = pos - sect_start;
		unsigned int size = sect_size - offset;
		if( size > len ) 
			size = len;

		if (size == sect_size) {
			/* 
			 * We are covering a whole sector.  Thus there is no
			 * need to bother with the cache while it may still be
			 * useful for other partial writes.
			 */
			ret = erase_write (mtd, pos, size, buf);
			if (ret)
				return ret;
		} else {
			/* Partial sector: need to use the cache */

			if (mtdblk->cache_state == STATE_DIRTY &&
			    mtdblk->cache_offset != sect_start) {
				ret = write_cached_data(mtdblk);
				if (ret) 
					return ret;
			}

			if (mtdblk->cache_state == STATE_EMPTY ||
			    mtdblk->cache_offset != sect_start) {
				/* fill the cache with the current sector */
				mtdblk->cache_state = STATE_EMPTY;
				ret = MTD_READ(mtd, sect_start, sect_size, &retlen, mtdblk->cache_data);
				if (ret)
					return ret;
				if (retlen != sect_size)
					return -EIO;

				mtdblk->cache_offset = sect_start;
				mtdblk->cache_size = sect_size;
				mtdblk->cache_state = STATE_CLEAN;
			}

			/* write data to our local cache */
			memcpy (mtdblk->cache_data + offset, buf, size);
			mtdblk->cache_state = STATE_DIRTY;
		}

		buf += size;
		pos += size;
		len -= size;
	}

	return 0;
}


static int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos, 
			   int len, char *buf)
{
	struct mtd_info *mtd = mtdblk->mtd;
	unsigned int sect_size = mtdblk->cache_size;
	size_t retlen;
	int ret;

	DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: read on \"%s\" at 0x%lx, size 0x%x\n", 
			mtd->name, pos, len);
	
	if (!sect_size)
		return MTD_READ (mtd, pos, len, &retlen, buf);

	while (len > 0) {
		unsigned long sect_start = (pos/sect_size)*sect_size;
		unsigned int offset = pos - sect_start;
		unsigned int size = sect_size - offset;
		if (size > len) 
			size = len;

		/*
		 * Check if the requested data is already cached
		 * Read the requested amount of data from our internal cache if it
		 * contains what we want, otherwise we read the data directly
		 * from flash.
		 */
		if (mtdblk->cache_state != STATE_EMPTY &&
		    mtdblk->cache_offset == sect_start) {
			memcpy (buf, mtdblk->cache_data + offset, size);
		} else {
			ret = MTD_READ (mtd, pos, size, &retlen, buf);
			if (ret)
				return ret;
			if (retlen != size)
				return -EIO;
		}

		buf += size;
		pos += size;
		len -= size;
	}

	return 0;
}

static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
			      unsigned long block, char *buf)
{
	struct mtdblk_dev *mtdblk = mtdblks[dev->devnum];
	return do_cached_read(mtdblk, block<<9, 512, buf);
}

static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
			      unsigned long block, char *buf)
{
	struct mtdblk_dev *mtdblk = mtdblks[dev->devnum];
	if (unlikely(!mtdblk->cache_data && mtdblk->cache_size)) {
		mtdblk->cache_data = vmalloc(mtdblk->mtd->erasesize);
		if (!mtdblk->cache_data)
			return -EINTR;
		/* -EINTR is not really correct, but it is the best match
		 * documented in man 2 write for all cases.  We could also
		 * return -EAGAIN sometimes, but why bother?
		 */
	}
	return do_cached_write(mtdblk, block<<9, 512, buf);
}

static int mtdblock_open(struct mtd_blktrans_dev *mbd)
{
	struct mtdblk_dev *mtdblk;
	struct mtd_info *mtd = mbd->mtd;
	int dev = mbd->devnum;

	DEBUG(MTD_DEBUG_LEVEL1,"mtdblock_open\n");
	
	if (mtdblks[dev]) {
		mtdblks[dev]->count++;
		return 0;
	}
	
	/* OK, it's not open. Create cache info for it */
	mtdblk = kmalloc(sizeof(struct mtdblk_dev), GFP_KERNEL);
	if (!mtdblk)
		return -ENOMEM;

	memset(mtdblk, 0, sizeof(*mtdblk));
	mtdblk->count = 1;
	mtdblk->mtd = mtd;

	init_MUTEX (&mtdblk->cache_sem);
	mtdblk->cache_state = STATE_EMPTY;
	if ((mtdblk->mtd->flags & MTD_CAP_RAM) != MTD_CAP_RAM &&
	    mtdblk->mtd->erasesize) {
		mtdblk->cache_size = mtdblk->mtd->erasesize;
		mtdblk->cache_data = NULL;
	}

	mtdblks[dev] = mtdblk;
	
	DEBUG(MTD_DEBUG_LEVEL1, "ok\n");

	return 0;
}

static int mtdblock_release(struct mtd_blktrans_dev *mbd)
{
	int dev = mbd->devnum;
	struct mtdblk_dev *mtdblk = mtdblks[dev];

   	DEBUG(MTD_DEBUG_LEVEL1, "mtdblock_release\n");

	down(&mtdblk->cache_sem);
	write_cached_data(mtdblk);
	up(&mtdblk->cache_sem);

	if (!--mtdblk->count) {
		/* It was the last usage. Free the device */
		mtdblks[dev] = NULL;
		if (mtdblk->mtd->sync)
			mtdblk->mtd->sync(mtdblk->mtd);
		vfree(mtdblk->cache_data);
		kfree(mtdblk);
	}
	DEBUG(MTD_DEBUG_LEVEL1, "ok\n");

	return 0;
}  

static int mtdblock_flush(struct mtd_blktrans_dev *dev)
{
	struct mtdblk_dev *mtdblk = mtdblks[dev->devnum];

	down(&mtdblk->cache_sem);
	write_cached_data(mtdblk);
	up(&mtdblk->cache_sem);

	if (mtdblk->mtd->sync)
		mtdblk->mtd->sync(mtdblk->mtd);
	return 0;
}

static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
{
	struct mtd_blktrans_dev *dev = kmalloc(sizeof(*dev), GFP_KERNEL);

	if (!dev)
		return;

	memset(dev, 0, sizeof(*dev));

	dev->mtd = mtd;
	dev->devnum = mtd->index;
	dev->blksize = 512;
	dev->size = mtd->size >> 9;
	dev->tr = tr;

	if (!(mtd->flags & MTD_WRITEABLE))
		dev->readonly = 1;

	add_mtd_blktrans_dev(dev);
}

static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
{
	del_mtd_blktrans_dev(dev);
	kfree(dev);
}

static struct mtd_blktrans_ops mtdblock_tr = {
	.name		= "mtdblock",
	.major		= 31,
	.part_bits	= 0,
	.open		= mtdblock_open,
	.flush		= mtdblock_flush,
	.release	= mtdblock_release,
	.readsect	= mtdblock_readsect,
	.writesect	= mtdblock_writesect,
	.add_mtd	= mtdblock_add_mtd,
	.remove_dev	= mtdblock_remove_dev,
	.owner		= THIS_MODULE,
};

static int __init init_mtdblock(void)
{
	return register_mtd_blktrans(&mtdblock_tr);
}

static void __exit cleanup_mtdblock(void)
{
	deregister_mtd_blktrans(&mtdblock_tr);
}

module_init(init_mtdblock);
module_exit(cleanup_mtdblock);


MODULE_LICENSE("GPL");
MODULE_AUTHOR("Nicolas Pitre <nico@cam.org> et al.");
MODULE_DESCRIPTION("Caching read/erase/writeback block device emulation access to MTD devices");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Direct MTD block device access
	3	*
	4	* $Id: mtdblock.c,v 1.66 2004/11/25 13:52:52 joern Exp $
	5	*
	6	* (C) 2000-2003 Nicolas Pitre <nico@cam.org>
	7	* (C) 1999-2003 David Woodhouse <dwmw2@infradead.org>
	8	*/
	9
	10	#include <linux/config.h>
	11	#include <linux/types.h>
	12	#include <linux/module.h>
	13	#include <linux/kernel.h>
	14	#include <linux/fs.h>
	15	#include <linux/init.h>
	16	#include <linux/slab.h>
	17	#include <linux/vmalloc.h>
4e57b681	18	#include <linux/sched.h> /* TASK_* */
1da177e4 LT	19	#include <linux/mtd/mtd.h>
	20	#include <linux/mtd/blktrans.h>
	21
	22	static struct mtdblk_dev {
	23	struct mtd_info *mtd;
	24	int count;
	25	struct semaphore cache_sem;
	26	unsigned char *cache_data;
	27	unsigned long cache_offset;
	28	unsigned int cache_size;
	29	enum { STATE_EMPTY, STATE_CLEAN, STATE_DIRTY } cache_state;
	30	} *mtdblks[MAX_MTD_DEVICES];
	31
	32	/*
	33	* Cache stuff...
	34	*
	35	* Since typical flash erasable sectors are much larger than what Linux's
	36	* buffer cache can handle, we must implement read-modify-write on flash
	37	* sectors for each block write requests. To avoid over-erasing flash sectors
	38	* and to speed things up, we locally cache a whole flash sector while it is
	39	* being written to until a different sector is required.
	40	*/
	41
	42	static void erase_callback(struct erase_info *done)
	43	{
	44	wait_queue_head_t wait_q = (wait_queue_head_t )done->priv;
	45	wake_up(wait_q);
	46	}
	47
	48	static int erase_write (struct mtd_info *mtd, unsigned long pos,
	49	int len, const char *buf)
	50	{
	51	struct erase_info erase;
	52	DECLARE_WAITQUEUE(wait, current);
	53	wait_queue_head_t wait_q;
	54	size_t retlen;
	55	int ret;
	56
	57	/*
	58	* First, let's erase the flash block.
	59	*/
	60
	61	init_waitqueue_head(&wait_q);
	62	erase.mtd = mtd;
	63	erase.callback = erase_callback;
	64	erase.addr = pos;
	65	erase.len = len;
	66	erase.priv = (u_long)&wait_q;
	67
	68	set_current_state(TASK_INTERRUPTIBLE);
	69	add_wait_queue(&wait_q, &wait);
	70
	71	ret = MTD_ERASE(mtd, &erase);
	72	if (ret) {
	73	set_current_state(TASK_RUNNING);
	74	remove_wait_queue(&wait_q, &wait);
	75	printk (KERN_WARNING "mtdblock: erase of region [0x%lx, 0x%x] "
	76	"on \"%s\" failed\n",
	77	pos, len, mtd->name);
	78	return ret;
	79	}
	80
	81	schedule(); /* Wait for erase to finish. */
	82	remove_wait_queue(&wait_q, &wait);
83
84	/*
85	* Next, writhe data to flash.
86	*/
87
88	ret = MTD_WRITE (mtd, pos, len, &retlen, buf);
89	if (ret)
90	return ret;
91	if (retlen != len)
92	return -EIO;
93	return 0;
94	}
95
96
97	static int write_cached_data (struct mtdblk_dev *mtdblk)
98	{
99	struct mtd_info *mtd = mtdblk->mtd;
100	int ret;
101
102	if (mtdblk->cache_state != STATE_DIRTY)
103	return 0;
104
105	DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: writing cached data for \"%s\" "
106	"at 0x%lx, size 0x%x\n", mtd->name,
107	mtdblk->cache_offset, mtdblk->cache_size);
108
109	ret = erase_write (mtd, mtdblk->cache_offset,
110	mtdblk->cache_size, mtdblk->cache_data);
111	if (ret)
112	return ret;
113
114	/*
115	* Here we could argubly set the cache state to STATE_CLEAN.
116	* However this could lead to inconsistency since we will not
117	* be notified if this content is altered on the flash by other
118	* means. Let's declare it empty and leave buffering tasks to
119	* the buffer cache instead.
120	*/
121	mtdblk->cache_state = STATE_EMPTY;
122	return 0;
123	}
124
125
126	static int do_cached_write (struct mtdblk_dev *mtdblk, unsigned long pos,
127	int len, const char *buf)
128	{
129	struct mtd_info *mtd = mtdblk->mtd;
130	unsigned int sect_size = mtdblk->cache_size;
131	size_t retlen;
132	int ret;
133
134	DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: write on \"%s\" at 0x%lx, size 0x%x\n",
135	mtd->name, pos, len);
136
137	if (!sect_size)
138	return MTD_WRITE (mtd, pos, len, &retlen, buf);
139
140	while (len > 0) {
141	unsigned long sect_start = (pos/sect_size)*sect_size;
142	unsigned int offset = pos - sect_start;
143	unsigned int size = sect_size - offset;
144	if( size > len )
145	size = len;
146
147	if (size == sect_size) {
148	/*
149	* We are covering a whole sector. Thus there is no
150	* need to bother with the cache while it may still be
151	* useful for other partial writes.
152	*/
153	ret = erase_write (mtd, pos, size, buf);
154	if (ret)
155	return ret;
156	} else {
157	/* Partial sector: need to use the cache */
158
159	if (mtdblk->cache_state == STATE_DIRTY &&
160	mtdblk->cache_offset != sect_start) {
161	ret = write_cached_data(mtdblk);
162	if (ret)
163	return ret;
164	}
165
166	if (mtdblk->cache_state == STATE_EMPTY \|\|
167	mtdblk->cache_offset != sect_start) {
168	/* fill the cache with the current sector */
169	mtdblk->cache_state = STATE_EMPTY;
170	ret = MTD_READ(mtd, sect_start, sect_size, &retlen, mtdblk->cache_data);
171	if (ret)
172	return ret;
173	if (retlen != sect_size)
174	return -EIO;
175
176	mtdblk->cache_offset = sect_start;
177	mtdblk->cache_size = sect_size;
178	mtdblk->cache_state = STATE_CLEAN;
179	}
180
181	/* write data to our local cache */
182	memcpy (mtdblk->cache_data + offset, buf, size);
183	mtdblk->cache_state = STATE_DIRTY;
184	}
185
186	buf += size;
187	pos += size;
188	len -= size;
189	}
190
191	return 0;
192	}
193
194
195	static int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos,
196	int len, char *buf)
197	{
198	struct mtd_info *mtd = mtdblk->mtd;
199	unsigned int sect_size = mtdblk->cache_size;
200	size_t retlen;
201	int ret;
202
203	DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: read on \"%s\" at 0x%lx, size 0x%x\n",
204	mtd->name, pos, len);
205
206	if (!sect_size)
207	return MTD_READ (mtd, pos, len, &retlen, buf);
208
209	while (len > 0) {
210	unsigned long sect_start = (pos/sect_size)*sect_size;
211	unsigned int offset = pos - sect_start;
212	unsigned int size = sect_size - offset;
213	if (size > len)
214	size = len;
215
216	/*
217	* Check if the requested data is already cached
218	* Read the requested amount of data from our internal cache if it
219	* contains what we want, otherwise we read the data directly
220	* from flash.
221	*/
222	if (mtdblk->cache_state != STATE_EMPTY &&
223	mtdblk->cache_offset == sect_start) {
224	memcpy (buf, mtdblk->cache_data + offset, size);
225	} else {
226	ret = MTD_READ (mtd, pos, size, &retlen, buf);
227	if (ret)
228	return ret;
229	if (retlen != size)
230	return -EIO;
231	}
232
233	buf += size;
234	pos += size;
235	len -= size;
236	}
237
238	return 0;
239	}
240
241	static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
242	unsigned long block, char *buf)
243	{
244	struct mtdblk_dev *mtdblk = mtdblks[dev->devnum];
245	return do_cached_read(mtdblk, block<<9, 512, buf);
246	}
247
248	static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
249	unsigned long block, char *buf)
250	{
251	struct mtdblk_dev *mtdblk = mtdblks[dev->devnum];
252	if (unlikely(!mtdblk->cache_data && mtdblk->cache_size)) {
253	mtdblk->cache_data = vmalloc(mtdblk->mtd->erasesize);
254	if (!mtdblk->cache_data)
255	return -EINTR;
256	/* -EINTR is not really correct, but it is the best match
257	* documented in man 2 write for all cases. We could also
258	* return -EAGAIN sometimes, but why bother?
259	*/
260	}
261	return do_cached_write(mtdblk, block<<9, 512, buf);
262	}
263
264	static int mtdblock_open(struct mtd_blktrans_dev *mbd)
265	{
266	struct mtdblk_dev *mtdblk;
267	struct mtd_info *mtd = mbd->mtd;
268	int dev = mbd->devnum;
269
270	DEBUG(MTD_DEBUG_LEVEL1,"mtdblock_open\n");
271
272	if (mtdblks[dev]) {
273	mtdblks[dev]->count++;
274	return 0;
275	}
276
277	/* OK, it's not open. Create cache info for it */
278	mtdblk = kmalloc(sizeof(struct mtdblk_dev), GFP_KERNEL);
279	if (!mtdblk)
280	return -ENOMEM;
281
282	memset(mtdblk, 0, sizeof(*mtdblk));
283	mtdblk->count = 1;
284	mtdblk->mtd = mtd;
285
286	init_MUTEX (&mtdblk->cache_sem);
287	mtdblk->cache_state = STATE_EMPTY;
288	if ((mtdblk->mtd->flags & MTD_CAP_RAM) != MTD_CAP_RAM &&
289	mtdblk->mtd->erasesize) {
290	mtdblk->cache_size = mtdblk->mtd->erasesize;
291	mtdblk->cache_data = NULL;
292	}
293
294	mtdblks[dev] = mtdblk;
295
296	DEBUG(MTD_DEBUG_LEVEL1, "ok\n");
297
298	return 0;
299	}
300
301	static int mtdblock_release(struct mtd_blktrans_dev *mbd)
302	{
303	int dev = mbd->devnum;
304	struct mtdblk_dev *mtdblk = mtdblks[dev];
305
306	DEBUG(MTD_DEBUG_LEVEL1, "mtdblock_release\n");
307
308	down(&mtdblk->cache_sem);
309	write_cached_data(mtdblk);
310	up(&mtdblk->cache_sem);
311
312	if (!--mtdblk->count) {
313	/* It was the last usage. Free the device */
314	mtdblks[dev] = NULL;
315	if (mtdblk->mtd->sync)
316	mtdblk->mtd->sync(mtdblk->mtd);
317	vfree(mtdblk->cache_data);
318	kfree(mtdblk);
319	}
320	DEBUG(MTD_DEBUG_LEVEL1, "ok\n");
321
322	return 0;
323	}
324
325	static int mtdblock_flush(struct mtd_blktrans_dev *dev)
326	{
327	struct mtdblk_dev *mtdblk = mtdblks[dev->devnum];
328
329	down(&mtdblk->cache_sem);
330	write_cached_data(mtdblk);
331	up(&mtdblk->cache_sem);
332
333	if (mtdblk->mtd->sync)
334	mtdblk->mtd->sync(mtdblk->mtd);
335	return 0;
336	}
337
338	static void mtdblock_add_mtd(struct mtd_blktrans_ops tr, struct mtd_info mtd)
339	{
340	struct mtd_blktrans_dev dev = kmalloc(sizeof(dev), GFP_KERNEL);
341
342	if (!dev)
343	return;
344
345	memset(dev, 0, sizeof(*dev));
346
347	dev->mtd = mtd;
348	dev->devnum = mtd->index;
349	dev->blksize = 512;
350	dev->size = mtd->size >> 9;
351	dev->tr = tr;
352
353	if (!(mtd->flags & MTD_WRITEABLE))
354	dev->readonly = 1;
355
356	add_mtd_blktrans_dev(dev);
357	}
358
359	static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
360	{
361	del_mtd_blktrans_dev(dev);
362	kfree(dev);
363	}
364
365	static struct mtd_blktrans_ops mtdblock_tr = {
366	.name = "mtdblock",
367	.major = 31,
368	.part_bits = 0,
369	.open = mtdblock_open,
370	.flush = mtdblock_flush,
371	.release = mtdblock_release,
372	.readsect = mtdblock_readsect,
373	.writesect = mtdblock_writesect,
374	.add_mtd = mtdblock_add_mtd,
375	.remove_dev = mtdblock_remove_dev,
376	.owner = THIS_MODULE,
377	};
378
379	static int __init init_mtdblock(void)
380	{
381	return register_mtd_blktrans(&mtdblock_tr);
382	}
383
384	static void __exit cleanup_mtdblock(void)
385	{
386	deregister_mtd_blktrans(&mtdblock_tr);
387	}
388
389	module_init(init_mtdblock);
390	module_exit(cleanup_mtdblock);
391
392
393	MODULE_LICENSE("GPL");
394	MODULE_AUTHOR("Nicolas Pitre <nico@cam.org> et al.");
395	MODULE_DESCRIPTION("Caching read/erase/writeback block device emulation access to MTD devices");