[mirror_ubuntu-jammy-kernel.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);

	/*
	 * 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.
	 *
	 * If this cache_offset points to a bad block, data cannot be
	 * written to the device. Clear cache_state to avoid writing to
	 * bad blocks repeatedly.
	 */
	if (ret == 0 || ret == -EIO)
		mtdblk->cache_state = STATE_EMPTY;
	return ret;
}


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;
	}

	if (mtd_type_is_nand(mbd->mtd))
		pr_warn("%s: MTD device '%s' is NAND, please consider using UBI block devices instead.\n",
			mbd->tr->name, mbd->mtd->name);

	/* 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);
	int ret;

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

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,
};

module_mtd_blktrans(mtdblock_tr);

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	91	mtdblk->cache_size, mtdblk->cache_data);
1da177e4 LT	92
1da177e4 LT	93	/*
25985edc	94	* Here we could arguably set the cache state to STATE_CLEAN.
97894cda TG	95	* However this could lead to inconsistency since we will not
97894cda TG	96	* be notified if this content is altered on the flash by other
1da177e4 LT	97	* means. Let's declare it empty and leave buffering tasks to
1da177e4 LT	98	* the buffer cache instead.
5788ccf3 XN	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.
1da177e4	103	*/
5788ccf3 XN	104	if (ret == 0 \|\| ret == -EIO)
	105	mtdblk->cache_state = STATE_EMPTY;
	106	return ret;
1da177e4 LT	107	}
	108
	109
97894cda	110	static int do_cached_write (struct mtdblk_dev *mtdblk, unsigned long pos,
1da177e4 LT	111	int len, const char *buf)
1da177e4 LT	112	{
cbfe93e9	113	struct mtd_info *mtd = mtdblk->mbd.mtd;
1da177e4 LT	114	unsigned int sect_size = mtdblk->cache_size;
	115	size_t retlen;
	116	int ret;
	117
289c0522	118	pr_debug("mtdblock: write on \"%s\" at 0x%lx, size 0x%x\n",
1da177e4	119	mtd->name, pos, len);
97894cda	120
1da177e4	121	if (!sect_size)
eda95cbf	122	return mtd_write(mtd, pos, len, &retlen, buf);
1da177e4 LT	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;
97894cda	128	if( size > len )
1da177e4 LT	129	size = len;
	130
	131	if (size == sect_size) {
97894cda	132	/*
1da177e4 LT	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);
97894cda	146	if (ret)
1da177e4 LT	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;
329ad399 AB	154	ret = mtd_read(mtd, sect_start, sect_size,
329ad399 AB	155	&retlen, mtdblk->cache_data);
1da177e4 LT	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
97894cda	180	static int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos,
1da177e4 LT	181	int len, char *buf)
1da177e4 LT	182	{
cbfe93e9	183	struct mtd_info *mtd = mtdblk->mbd.mtd;
1da177e4 LT	184	unsigned int sect_size = mtdblk->cache_size;
	185	size_t retlen;
	186	int ret;
	187
289c0522	188	pr_debug("mtdblock: read on \"%s\" at 0x%lx, size 0x%x\n",
1da177e4	189	mtd->name, pos, len);
97894cda	190
1da177e4	191	if (!sect_size)
329ad399	192	return mtd_read(mtd, pos, len, &retlen, buf);
1da177e4 LT	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;
97894cda	198	if (size > len)
1da177e4 LT	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 {
329ad399	211	ret = mtd_read(mtd, pos, size, &retlen, buf);
1da177e4 LT	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
	226	static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
	227	unsigned long block, char *buf)
	228	{
cbfe93e9	229	struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
1da177e4 LT	230	return do_cached_read(mtdblk, block<<9, 512, buf);
	231	}
	232
	233	static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
	234	unsigned long block, char *buf)
	235	{
cbfe93e9	236	struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
1da177e4	237	if (unlikely(!mtdblk->cache_data && mtdblk->cache_size)) {
cbfe93e9	238	mtdblk->cache_data = vmalloc(mtdblk->mbd.mtd->erasesize);
1da177e4 LT	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
	249	static int mtdblock_open(struct mtd_blktrans_dev *mbd)
	250	{
cbfe93e9	251	struct mtdblk_dev *mtdblk = container_of(mbd, struct mtdblk_dev, mbd);
1da177e4	252
289c0522	253	pr_debug("mtdblock_open\n");
97894cda	254
cbfe93e9 BH	255	if (mtdblk->count) {
cbfe93e9 BH	256	mtdblk->count++;
1da177e4 LT	257	return 0;
1da177e4 LT	258	}
97894cda	259
b2ad947f BM	260	if (mtd_type_is_nand(mbd->mtd))
	261	pr_warn("%s: MTD device '%s' is NAND, please consider using UBI block devices instead.\n",
	262	mbd->tr->name, mbd->mtd->name);
	263
1da177e4	264	/* OK, it's not open. Create cache info for it */
1da177e4	265	mtdblk->count = 1;
48b19268	266	mutex_init(&mtdblk->cache_mutex);
1da177e4	267	mtdblk->cache_state = STATE_EMPTY;
cbfe93e9 BH	268	if (!(mbd->mtd->flags & MTD_NO_ERASE) && mbd->mtd->erasesize) {
cbfe93e9 BH	269	mtdblk->cache_size = mbd->mtd->erasesize;
1da177e4 LT	270	mtdblk->cache_data = NULL;
	271	}
	272
289c0522	273	pr_debug("ok\n");
1da177e4 LT	274
	275	return 0;
	276	}
	277
a8ca889e	278	static void mtdblock_release(struct mtd_blktrans_dev *mbd)
1da177e4	279	{
cbfe93e9	280	struct mtdblk_dev *mtdblk = container_of(mbd, struct mtdblk_dev, mbd);
1da177e4	281
289c0522	282	pr_debug("mtdblock_release\n");
1da177e4	283
48b19268	284	mutex_lock(&mtdblk->cache_mutex);
1da177e4	285	write_cached_data(mtdblk);
48b19268	286	mutex_unlock(&mtdblk->cache_mutex);
1da177e4 LT	287
1da177e4 LT	288	if (!--mtdblk->count) {
70d5098a AS	289	/*
	290	* It was the last usage. Free the cache, but only sync if
	291	* opened for writing.
	292	*/
	293	if (mbd->file_mode & FMODE_WRITE)
	294	mtd_sync(mbd->mtd);
1da177e4	295	vfree(mtdblk->cache_data);
1da177e4	296	}
d676c117	297
289c0522	298	pr_debug("ok\n");
97894cda	299	}
1da177e4 LT	300
	301	static int mtdblock_flush(struct mtd_blktrans_dev *dev)
	302	{
cbfe93e9	303	struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
4e4a9a82	304	int ret;
1da177e4	305
48b19268	306	mutex_lock(&mtdblk->cache_mutex);
4e4a9a82	307	ret = write_cached_data(mtdblk);
48b19268	308	mutex_unlock(&mtdblk->cache_mutex);
327cf292	309	mtd_sync(dev->mtd);
4e4a9a82	310	return ret;
1da177e4 LT	311	}
	312
	313	static void mtdblock_add_mtd(struct mtd_blktrans_ops tr, struct mtd_info mtd)
	314	{
cbfe93e9	315	struct mtdblk_dev dev = kzalloc(sizeof(dev), GFP_KERNEL);
1da177e4 LT	316
	317	if (!dev)
	318	return;
	319
cbfe93e9 BH	320	dev->mbd.mtd = mtd;
cbfe93e9 BH	321	dev->mbd.devnum = mtd->index;
19187672	322
cbfe93e9 BH	323	dev->mbd.size = mtd->size >> 9;
cbfe93e9 BH	324	dev->mbd.tr = tr;
1da177e4 LT	325
1da177e4 LT	326	if (!(mtd->flags & MTD_WRITEABLE))
cbfe93e9	327	dev->mbd.readonly = 1;
1da177e4	328
298304f1 ML	329	if (add_mtd_blktrans_dev(&dev->mbd))
298304f1 ML	330	kfree(dev);
1da177e4 LT	331	}
	332
	333	static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
	334	{
	335	del_mtd_blktrans_dev(dev);
1da177e4 LT	336	}
	337
	338	static struct mtd_blktrans_ops mtdblock_tr = {
	339	.name = "mtdblock",
2aabeb20	340	.major = MTD_BLOCK_MAJOR,
1da177e4	341	.part_bits = 0,
19187672	342	.blksize = 512,
1da177e4 LT	343	.open = mtdblock_open,
	344	.flush = mtdblock_flush,
	345	.release = mtdblock_release,
	346	.readsect = mtdblock_readsect,
	347	.writesect = mtdblock_writesect,
	348	.add_mtd = mtdblock_add_mtd,
	349	.remove_dev = mtdblock_remove_dev,
	350	.owner = THIS_MODULE,
	351	};
	352
27b08bf3	353	module_mtd_blktrans(mtdblock_tr);
1da177e4 LT	354
1da177e4 LT	355	MODULE_LICENSE("GPL");
2f82af08	356	MODULE_AUTHOR("Nicolas Pitre <nico@fluxnic.net> et al.");
1da177e4	357	MODULE_DESCRIPTION("Caching read/erase/writeback block device emulation access to MTD devices");