[linux-2.6-block.git] / drivers / mtd / mtdblock.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Direct MTD block device access
 *
 * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
 * Copyright © 2000-2003 Nicolas Pitre <nico@fluxnic.net>
 */

#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/vmalloc.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/blktrans.h>
#include <linux/mutex.h>
#include <linux/major.h>


struct mtdblk_dev {
	struct mtd_blktrans_dev mbd;
	int count;
	struct mutex cache_mutex;
	unsigned char *cache_data;
	unsigned long cache_offset;
	unsigned int cache_size;
	enum { STATE_EMPTY, STATE_CLEAN, STATE_DIRTY } cache_state;
};

/*
 * 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 int erase_write (struct mtd_info *mtd, unsigned long pos,
			unsigned int len, const char *buf)
{
	struct erase_info erase;
	size_t retlen;
	int ret;

	/*
	 * First, let's erase the flash block.
	 */
	erase.addr = pos;
	erase.len = len;

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

	/*
	 * Next, write the 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->mbd.mtd;
	int ret;

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

	pr_debug("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 arguably 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->mbd.mtd;
	unsigned int sect_size = mtdblk->cache_size;
	size_t retlen;
	int ret;

	pr_debug("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->mbd.mtd;
	unsigned int sect_size = mtdblk->cache_size;
	size_t retlen;
	int ret;

	pr_debug("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 = container_of(dev, struct mtdblk_dev, mbd);
	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 = container_of(dev, struct mtdblk_dev, mbd);
	if (unlikely(!mtdblk->cache_data && mtdblk->cache_size)) {
		mtdblk->cache_data = vmalloc(mtdblk->mbd.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 = container_of(mbd, struct mtdblk_dev, mbd);

	pr_debug("mtdblock_open\n");

	if (mtdblk->count) {
		mtdblk->count++;
		return 0;
	}

	/* OK, it's not open. Create cache info for it */
	mtdblk->count = 1;
	mutex_init(&mtdblk->cache_mutex);
	mtdblk->cache_state = STATE_EMPTY;
	if (!(mbd->mtd->flags & MTD_NO_ERASE) && mbd->mtd->erasesize) {
		mtdblk->cache_size = mbd->mtd->erasesize;
		mtdblk->cache_data = NULL;
	}

	pr_debug("ok\n");

	return 0;
}

static void mtdblock_release(struct mtd_blktrans_dev *mbd)
{
	struct mtdblk_dev *mtdblk = container_of(mbd, struct mtdblk_dev, mbd);

	pr_debug("mtdblock_release\n");

	mutex_lock(&mtdblk->cache_mutex);
	write_cached_data(mtdblk);
	mutex_unlock(&mtdblk->cache_mutex);

	if (!--mtdblk->count) {
		/*
		 * It was the last usage. Free the cache, but only sync if
		 * opened for writing.
		 */
		if (mbd->file_mode & FMODE_WRITE)
			mtd_sync(mbd->mtd);
		vfree(mtdblk->cache_data);
	}

	pr_debug("ok\n");
}

static int mtdblock_flush(struct mtd_blktrans_dev *dev)
{
	struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);

	mutex_lock(&mtdblk->cache_mutex);
	write_cached_data(mtdblk);
	mutex_unlock(&mtdblk->cache_mutex);
	mtd_sync(dev->mtd);
	return 0;
}

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

	if (!dev)
		return;

	dev->mbd.mtd = mtd;
	dev->mbd.devnum = mtd->index;

	dev->mbd.size = mtd->size >> 9;
	dev->mbd.tr = tr;

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

	if (add_mtd_blktrans_dev(&dev->mbd))
		kfree(dev);
}

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

static struct mtd_blktrans_ops mtdblock_tr = {
	.name		= "mtdblock",
	.major		= MTD_BLOCK_MAJOR,
	.part_bits	= 0,
	.blksize 	= 512,
	.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@fluxnic.net> et al.");
MODULE_DESCRIPTION("Caching read/erase/writeback block device emulation access to MTD devices");
Commit	Line	Data
fd534e9b	1	// SPDX-License-Identifier: GPL-2.0-or-later
97894cda	2	/*
1da177e4 LT	3	* Direct MTD block device access
1da177e4 LT	4	*
a1452a37 DW	5	* Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
a1452a37 DW	6	* Copyright © 2000-2003 Nicolas Pitre <nico@fluxnic.net>
1da177e4 LT	7	*/
1da177e4 LT	8
1da177e4 LT	9	#include <linux/fs.h>
1da177e4 LT	10	#include <linux/init.h>
15fdc52f TG	11	#include <linux/kernel.h>
	12	#include <linux/module.h>
	13	#include <linux/sched.h>
1da177e4	14	#include <linux/slab.h>
15fdc52f	15	#include <linux/types.h>
1da177e4	16	#include <linux/vmalloc.h>
15fdc52f	17
1da177e4 LT	18	#include <linux/mtd/mtd.h>
1da177e4 LT	19	#include <linux/mtd/blktrans.h>
48b19268	20	#include <linux/mutex.h>
f83c3838	21	#include <linux/major.h>
48b19268	22
1da177e4	23
cbfe93e9 BH	24	struct mtdblk_dev {
cbfe93e9 BH	25	struct mtd_blktrans_dev mbd;
1da177e4	26	int count;
48b19268	27	struct mutex cache_mutex;
1da177e4 LT	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;
cbfe93e9	32	};
1da177e4 LT	33
	34	/*
	35	* Cache stuff...
97894cda	36	*
1da177e4 LT	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
97894cda	44	static int erase_write (struct mtd_info *mtd, unsigned long pos,
bafae538	45	unsigned int len, const char *buf)
1da177e4 LT	46	{
1da177e4 LT	47	struct erase_info erase;
1da177e4 LT	48	size_t retlen;
	49	int ret;
	50
	51	/*
	52	* First, let's erase the flash block.
	53	*/
1da177e4 LT	54	erase.addr = pos;
1da177e4 LT	55	erase.len = len;
1da177e4	56
7e1f0dc0	57	ret = mtd_erase(mtd, &erase);
1da177e4	58	if (ret) {
1da177e4 LT	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
1da177e4	65	/*
dff15509	66	* Next, write the data to flash.
1da177e4 LT	67	*/
1da177e4 LT	68
eda95cbf	69	ret = mtd_write(mtd, pos, len, &retlen, buf);
1da177e4 LT	70	if (ret)
	71	return ret;
	72	if (retlen != len)
	73	return -EIO;
	74	return 0;
	75	}
	76
	77
	78	static int write_cached_data (struct mtdblk_dev *mtdblk)
	79	{
cbfe93e9	80	struct mtd_info *mtd = mtdblk->mbd.mtd;
1da177e4 LT	81	int ret;
	82
	83	if (mtdblk->cache_state != STATE_DIRTY)
	84	return 0;
	85
289c0522	86	pr_debug("mtdblock: writing cached data for \"%s\" "
97894cda	87	"at 0x%lx, size 0x%x\n", mtd->name,
1da177e4	88	mtdblk->cache_offset, mtdblk->cache_size);
97894cda TG	89
97894cda TG	90	ret = erase_write (mtd, mtdblk->cache_offset,
1da177e4 LT	91	mtdblk->cache_size, mtdblk->cache_data);
	92	if (ret)
	93	return ret;
	94
	95	/*
25985edc	96	* Here we could arguably set the cache state to STATE_CLEAN.
97894cda TG	97	* However this could lead to inconsistency since we will not
97894cda TG	98	* be notified if this content is altered on the flash by other
1da177e4 LT	99	* means. Let's declare it empty and leave buffering tasks to
	100	* the buffer cache instead.
	101	*/
	102	mtdblk->cache_state = STATE_EMPTY;
	103	return 0;
	104	}
	105
	106
97894cda	107	static int do_cached_write (struct mtdblk_dev *mtdblk, unsigned long pos,
1da177e4 LT	108	int len, const char *buf)
1da177e4 LT	109	{
cbfe93e9	110	struct mtd_info *mtd = mtdblk->mbd.mtd;
1da177e4 LT	111	unsigned int sect_size = mtdblk->cache_size;
	112	size_t retlen;
	113	int ret;
	114
289c0522	115	pr_debug("mtdblock: write on \"%s\" at 0x%lx, size 0x%x\n",
1da177e4	116	mtd->name, pos, len);
97894cda	117
1da177e4	118	if (!sect_size)
eda95cbf	119	return mtd_write(mtd, pos, len, &retlen, buf);
1da177e4 LT	120
	121	while (len > 0) {
	122	unsigned long sect_start = (pos/sect_size)*sect_size;
	123	unsigned int offset = pos - sect_start;
	124	unsigned int size = sect_size - offset;
97894cda	125	if( size > len )
1da177e4 LT	126	size = len;
	127
	128	if (size == sect_size) {
97894cda	129	/*
1da177e4 LT	130	* We are covering a whole sector. Thus there is no
	131	* need to bother with the cache while it may still be
	132	* useful for other partial writes.
	133	*/
	134	ret = erase_write (mtd, pos, size, buf);
	135	if (ret)
	136	return ret;
	137	} else {
	138	/* Partial sector: need to use the cache */
	139
	140	if (mtdblk->cache_state == STATE_DIRTY &&
	141	mtdblk->cache_offset != sect_start) {
	142	ret = write_cached_data(mtdblk);
97894cda	143	if (ret)
1da177e4 LT	144	return ret;
	145	}
	146
	147	if (mtdblk->cache_state == STATE_EMPTY \|\|
	148	mtdblk->cache_offset != sect_start) {
	149	/* fill the cache with the current sector */
	150	mtdblk->cache_state = STATE_EMPTY;
329ad399 AB	151	ret = mtd_read(mtd, sect_start, sect_size,
329ad399 AB	152	&retlen, mtdblk->cache_data);
1da177e4 LT	153	if (ret)
	154	return ret;
	155	if (retlen != sect_size)
	156	return -EIO;
	157
	158	mtdblk->cache_offset = sect_start;
	159	mtdblk->cache_size = sect_size;
	160	mtdblk->cache_state = STATE_CLEAN;
	161	}
	162
	163	/* write data to our local cache */
	164	memcpy (mtdblk->cache_data + offset, buf, size);
	165	mtdblk->cache_state = STATE_DIRTY;
	166	}
	167
	168	buf += size;
	169	pos += size;
	170	len -= size;
	171	}
	172
	173	return 0;
	174	}
	175
	176
97894cda	177	static int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos,
1da177e4 LT	178	int len, char *buf)
1da177e4 LT	179	{
cbfe93e9	180	struct mtd_info *mtd = mtdblk->mbd.mtd;
1da177e4 LT	181	unsigned int sect_size = mtdblk->cache_size;
	182	size_t retlen;
	183	int ret;
	184
289c0522	185	pr_debug("mtdblock: read on \"%s\" at 0x%lx, size 0x%x\n",
1da177e4	186	mtd->name, pos, len);
97894cda	187
1da177e4	188	if (!sect_size)
329ad399	189	return mtd_read(mtd, pos, len, &retlen, buf);
1da177e4 LT	190
	191	while (len > 0) {
	192	unsigned long sect_start = (pos/sect_size)*sect_size;
	193	unsigned int offset = pos - sect_start;
	194	unsigned int size = sect_size - offset;
97894cda	195	if (size > len)
1da177e4 LT	196	size = len;
	197
	198	/*
	199	* Check if the requested data is already cached
	200	* Read the requested amount of data from our internal cache if it
	201	* contains what we want, otherwise we read the data directly
	202	* from flash.
	203	*/
	204	if (mtdblk->cache_state != STATE_EMPTY &&
	205	mtdblk->cache_offset == sect_start) {
	206	memcpy (buf, mtdblk->cache_data + offset, size);
	207	} else {
329ad399	208	ret = mtd_read(mtd, pos, size, &retlen, buf);
1da177e4 LT	209	if (ret)
	210	return ret;
	211	if (retlen != size)
	212	return -EIO;
	213	}
	214
	215	buf += size;
	216	pos += size;
	217	len -= size;
	218	}
	219
	220	return 0;
	221	}
	222
	223	static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
	224	unsigned long block, char *buf)
	225	{
cbfe93e9	226	struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
1da177e4 LT	227	return do_cached_read(mtdblk, block<<9, 512, buf);
	228	}
	229
	230	static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
	231	unsigned long block, char *buf)
	232	{
cbfe93e9	233	struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
1da177e4	234	if (unlikely(!mtdblk->cache_data && mtdblk->cache_size)) {
cbfe93e9	235	mtdblk->cache_data = vmalloc(mtdblk->mbd.mtd->erasesize);
1da177e4 LT	236	if (!mtdblk->cache_data)
	237	return -EINTR;
	238	/* -EINTR is not really correct, but it is the best match
	239	* documented in man 2 write for all cases. We could also
	240	* return -EAGAIN sometimes, but why bother?
	241	*/
	242	}
	243	return do_cached_write(mtdblk, block<<9, 512, buf);
	244	}
	245
	246	static int mtdblock_open(struct mtd_blktrans_dev *mbd)
	247	{
cbfe93e9	248	struct mtdblk_dev *mtdblk = container_of(mbd, struct mtdblk_dev, mbd);
1da177e4	249
289c0522	250	pr_debug("mtdblock_open\n");
97894cda	251
cbfe93e9 BH	252	if (mtdblk->count) {
cbfe93e9 BH	253	mtdblk->count++;
1da177e4 LT	254	return 0;
1da177e4 LT	255	}
97894cda	256
1da177e4	257	/* OK, it's not open. Create cache info for it */
1da177e4	258	mtdblk->count = 1;
48b19268	259	mutex_init(&mtdblk->cache_mutex);
1da177e4	260	mtdblk->cache_state = STATE_EMPTY;
cbfe93e9 BH	261	if (!(mbd->mtd->flags & MTD_NO_ERASE) && mbd->mtd->erasesize) {
cbfe93e9 BH	262	mtdblk->cache_size = mbd->mtd->erasesize;
1da177e4 LT	263	mtdblk->cache_data = NULL;
	264	}
	265
289c0522	266	pr_debug("ok\n");
1da177e4 LT	267
	268	return 0;
	269	}
	270
a8ca889e	271	static void mtdblock_release(struct mtd_blktrans_dev *mbd)
1da177e4	272	{
cbfe93e9	273	struct mtdblk_dev *mtdblk = container_of(mbd, struct mtdblk_dev, mbd);
1da177e4	274
289c0522	275	pr_debug("mtdblock_release\n");
1da177e4	276
48b19268	277	mutex_lock(&mtdblk->cache_mutex);
1da177e4	278	write_cached_data(mtdblk);
48b19268	279	mutex_unlock(&mtdblk->cache_mutex);
1da177e4 LT	280
1da177e4 LT	281	if (!--mtdblk->count) {
70d5098a AS	282	/*
	283	* It was the last usage. Free the cache, but only sync if
	284	* opened for writing.
	285	*/
	286	if (mbd->file_mode & FMODE_WRITE)
	287	mtd_sync(mbd->mtd);
1da177e4	288	vfree(mtdblk->cache_data);
1da177e4	289	}
d676c117	290
289c0522	291	pr_debug("ok\n");
97894cda	292	}
1da177e4 LT	293
	294	static int mtdblock_flush(struct mtd_blktrans_dev *dev)
	295	{
cbfe93e9	296	struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
1da177e4	297
48b19268	298	mutex_lock(&mtdblk->cache_mutex);
1da177e4	299	write_cached_data(mtdblk);
48b19268	300	mutex_unlock(&mtdblk->cache_mutex);
327cf292	301	mtd_sync(dev->mtd);
1da177e4 LT	302	return 0;
	303	}
	304
	305	static void mtdblock_add_mtd(struct mtd_blktrans_ops tr, struct mtd_info mtd)
	306	{
cbfe93e9	307	struct mtdblk_dev dev = kzalloc(sizeof(dev), GFP_KERNEL);
1da177e4 LT	308
	309	if (!dev)
	310	return;
	311
cbfe93e9 BH	312	dev->mbd.mtd = mtd;
cbfe93e9 BH	313	dev->mbd.devnum = mtd->index;
19187672	314
cbfe93e9 BH	315	dev->mbd.size = mtd->size >> 9;
cbfe93e9 BH	316	dev->mbd.tr = tr;
1da177e4 LT	317
1da177e4 LT	318	if (!(mtd->flags & MTD_WRITEABLE))
cbfe93e9	319	dev->mbd.readonly = 1;
1da177e4	320
298304f1 ML	321	if (add_mtd_blktrans_dev(&dev->mbd))
298304f1 ML	322	kfree(dev);
1da177e4 LT	323	}
	324
	325	static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
	326	{
	327	del_mtd_blktrans_dev(dev);
1da177e4 LT	328	}
	329
	330	static struct mtd_blktrans_ops mtdblock_tr = {
	331	.name = "mtdblock",
2aabeb20	332	.major = MTD_BLOCK_MAJOR,
1da177e4	333	.part_bits = 0,
19187672	334	.blksize = 512,
1da177e4 LT	335	.open = mtdblock_open,
	336	.flush = mtdblock_flush,
	337	.release = mtdblock_release,
	338	.readsect = mtdblock_readsect,
	339	.writesect = mtdblock_writesect,
	340	.add_mtd = mtdblock_add_mtd,
	341	.remove_dev = mtdblock_remove_dev,
	342	.owner = THIS_MODULE,
	343	};
	344
	345	static int __init init_mtdblock(void)
	346	{
	347	return register_mtd_blktrans(&mtdblock_tr);
	348	}
	349
	350	static void __exit cleanup_mtdblock(void)
	351	{
	352	deregister_mtd_blktrans(&mtdblock_tr);
	353	}
	354
	355	module_init(init_mtdblock);
	356	module_exit(cleanup_mtdblock);
	357
	358
	359	MODULE_LICENSE("GPL");
2f82af08	360	MODULE_AUTHOR("Nicolas Pitre <nico@fluxnic.net> et al.");
1da177e4	361	MODULE_DESCRIPTION("Caching read/erase/writeback block device emulation access to MTD devices");