[net-next-2.6.git] / drivers / mtd / mtdblock.c

/*
 * Direct MTD block device access
 *
 * (C) 2000-2003 Nicolas Pitre <nico@cam.org>
 * (C) 1999-2003 David Woodhouse <dwmw2@infradead.org>
 */

#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>


static struct mtdblk_dev {
	struct mtd_info *mtd;
	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;
} *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 = kzalloc(sizeof(struct mtdblk_dev), GFP_KERNEL);
	if (!mtdblk)
		return -ENOMEM;

	mtdblk->count = 1;
	mtdblk->mtd = mtd;

	mutex_init(&mtdblk->cache_mutex);
	mtdblk->cache_state = STATE_EMPTY;
	if ( !(mtdblk->mtd->flags & MTD_NO_ERASE) && 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");

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

	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];

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

	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 = kzalloc(sizeof(*dev), GFP_KERNEL);

	if (!dev)
		return;

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

	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,
	.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@cam.org> et al.");
MODULE_DESCRIPTION("Caching read/erase/writeback block device emulation access to MTD devices");
Commit	Line	Data
97894cda	1	/*
1da177e4 LT	2	* Direct MTD block device access
1da177e4 LT	3	*
1da177e4 LT	4	* (C) 2000-2003 Nicolas Pitre <nico@cam.org>
	5	* (C) 1999-2003 David Woodhouse <dwmw2@infradead.org>
	6	*/
	7
1da177e4 LT	8	#include <linux/fs.h>
1da177e4 LT	9	#include <linux/init.h>
15fdc52f TG	10	#include <linux/kernel.h>
	11	#include <linux/module.h>
	12	#include <linux/sched.h>
1da177e4	13	#include <linux/slab.h>
15fdc52f	14	#include <linux/types.h>
1da177e4	15	#include <linux/vmalloc.h>
15fdc52f	16
1da177e4 LT	17	#include <linux/mtd/mtd.h>
1da177e4 LT	18	#include <linux/mtd/blktrans.h>
48b19268 IM	19	#include <linux/mutex.h>
48b19268 IM	20
1da177e4 LT	21
	22	static struct mtdblk_dev {
	23	struct mtd_info *mtd;
	24	int count;
48b19268	25	struct mutex cache_mutex;
1da177e4 LT	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...
97894cda	34	*
1da177e4 LT	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
97894cda	48	static int erase_write (struct mtd_info *mtd, unsigned long pos,
1da177e4 LT	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
f4a43cfc	71	ret = mtd->erase(mtd, &erase);
1da177e4 LT	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
f4a43cfc	88	ret = mtd->write(mtd, pos, len, &retlen, buf);
1da177e4 LT	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\" "
97894cda	106	"at 0x%lx, size 0x%x\n", mtd->name,
1da177e4	107	mtdblk->cache_offset, mtdblk->cache_size);
97894cda TG	108
97894cda TG	109	ret = erase_write (mtd, mtdblk->cache_offset,
1da177e4 LT	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.
97894cda TG	116	* However this could lead to inconsistency since we will not
97894cda TG	117	* be notified if this content is altered on the flash by other
1da177e4 LT	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
97894cda	126	static int do_cached_write (struct mtdblk_dev *mtdblk, unsigned long pos,
1da177e4 LT	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);
97894cda	136
1da177e4	137	if (!sect_size)
f4a43cfc	138	return mtd->write(mtd, pos, len, &retlen, buf);
1da177e4 LT	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;
97894cda	144	if( size > len )
1da177e4 LT	145	size = len;
	146
	147	if (size == sect_size) {
97894cda	148	/*
1da177e4 LT	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);
97894cda	162	if (ret)
1da177e4 LT	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;
f4a43cfc TG	170	ret = mtd->read(mtd, sect_start, sect_size,
f4a43cfc TG	171	&retlen, mtdblk->cache_data);
1da177e4 LT	172	if (ret)
	173	return ret;
	174	if (retlen != sect_size)
	175	return -EIO;
	176
	177	mtdblk->cache_offset = sect_start;
	178	mtdblk->cache_size = sect_size;
	179	mtdblk->cache_state = STATE_CLEAN;
	180	}
	181
	182	/* write data to our local cache */
	183	memcpy (mtdblk->cache_data + offset, buf, size);
	184	mtdblk->cache_state = STATE_DIRTY;
	185	}
	186
	187	buf += size;
	188	pos += size;
	189	len -= size;
	190	}
	191
	192	return 0;
	193	}
	194
	195
97894cda	196	static int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos,
1da177e4 LT	197	int len, char *buf)
	198	{
	199	struct mtd_info *mtd = mtdblk->mtd;
	200	unsigned int sect_size = mtdblk->cache_size;
	201	size_t retlen;
	202	int ret;
	203
97894cda	204	DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: read on \"%s\" at 0x%lx, size 0x%x\n",
1da177e4	205	mtd->name, pos, len);
97894cda	206
1da177e4	207	if (!sect_size)
f4a43cfc	208	return mtd->read(mtd, pos, len, &retlen, buf);
1da177e4 LT	209
	210	while (len > 0) {
	211	unsigned long sect_start = (pos/sect_size)*sect_size;
	212	unsigned int offset = pos - sect_start;
	213	unsigned int size = sect_size - offset;
97894cda	214	if (size > len)
1da177e4 LT	215	size = len;
	216
	217	/*
	218	* Check if the requested data is already cached
	219	* Read the requested amount of data from our internal cache if it
	220	* contains what we want, otherwise we read the data directly
	221	* from flash.
	222	*/
	223	if (mtdblk->cache_state != STATE_EMPTY &&
	224	mtdblk->cache_offset == sect_start) {
	225	memcpy (buf, mtdblk->cache_data + offset, size);
	226	} else {
f4a43cfc	227	ret = mtd->read(mtd, pos, size, &retlen, buf);
1da177e4 LT	228	if (ret)
	229	return ret;
	230	if (retlen != size)
	231	return -EIO;
	232	}
	233
	234	buf += size;
	235	pos += size;
	236	len -= size;
	237	}
	238
	239	return 0;
	240	}
	241
	242	static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
	243	unsigned long block, char *buf)
	244	{
	245	struct mtdblk_dev *mtdblk = mtdblks[dev->devnum];
	246	return do_cached_read(mtdblk, block<<9, 512, buf);
	247	}
	248
	249	static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
	250	unsigned long block, char *buf)
	251	{
	252	struct mtdblk_dev *mtdblk = mtdblks[dev->devnum];
	253	if (unlikely(!mtdblk->cache_data && mtdblk->cache_size)) {
	254	mtdblk->cache_data = vmalloc(mtdblk->mtd->erasesize);
	255	if (!mtdblk->cache_data)
	256	return -EINTR;
	257	/* -EINTR is not really correct, but it is the best match
	258	* documented in man 2 write for all cases. We could also
	259	* return -EAGAIN sometimes, but why bother?
	260	*/
	261	}
	262	return do_cached_write(mtdblk, block<<9, 512, buf);
	263	}
	264
	265	static int mtdblock_open(struct mtd_blktrans_dev *mbd)
	266	{
	267	struct mtdblk_dev *mtdblk;
	268	struct mtd_info *mtd = mbd->mtd;
	269	int dev = mbd->devnum;
	270
	271	DEBUG(MTD_DEBUG_LEVEL1,"mtdblock_open\n");
97894cda	272
1da177e4 LT	273	if (mtdblks[dev]) {
	274	mtdblks[dev]->count++;
	275	return 0;
	276	}
97894cda	277
1da177e4	278	/* OK, it's not open. Create cache info for it */
95b93a0c	279	mtdblk = kzalloc(sizeof(struct mtdblk_dev), GFP_KERNEL);
1da177e4 LT	280	if (!mtdblk)
	281	return -ENOMEM;
	282
1da177e4 LT	283	mtdblk->count = 1;
	284	mtdblk->mtd = mtd;
	285
48b19268	286	mutex_init(&mtdblk->cache_mutex);
1da177e4	287	mtdblk->cache_state = STATE_EMPTY;
92cbfdcc	288	if ( !(mtdblk->mtd->flags & MTD_NO_ERASE) && mtdblk->mtd->erasesize) {
1da177e4 LT	289	mtdblk->cache_size = mtdblk->mtd->erasesize;
	290	mtdblk->cache_data = NULL;
	291	}
	292
	293	mtdblks[dev] = mtdblk;
97894cda	294
1da177e4 LT	295	DEBUG(MTD_DEBUG_LEVEL1, "ok\n");
	296
	297	return 0;
	298	}
	299
	300	static int mtdblock_release(struct mtd_blktrans_dev *mbd)
	301	{
	302	int dev = mbd->devnum;
	303	struct mtdblk_dev *mtdblk = mtdblks[dev];
	304
	305	DEBUG(MTD_DEBUG_LEVEL1, "mtdblock_release\n");
	306
48b19268	307	mutex_lock(&mtdblk->cache_mutex);
1da177e4	308	write_cached_data(mtdblk);
48b19268	309	mutex_unlock(&mtdblk->cache_mutex);
1da177e4 LT	310
	311	if (!--mtdblk->count) {
	312	/* It was the last usage. Free the device */
	313	mtdblks[dev] = NULL;
	314	if (mtdblk->mtd->sync)
	315	mtdblk->mtd->sync(mtdblk->mtd);
	316	vfree(mtdblk->cache_data);
	317	kfree(mtdblk);
	318	}
	319	DEBUG(MTD_DEBUG_LEVEL1, "ok\n");
	320
	321	return 0;
97894cda	322	}
1da177e4 LT	323
	324	static int mtdblock_flush(struct mtd_blktrans_dev *dev)
	325	{
	326	struct mtdblk_dev *mtdblk = mtdblks[dev->devnum];
	327
48b19268	328	mutex_lock(&mtdblk->cache_mutex);
1da177e4	329	write_cached_data(mtdblk);
48b19268	330	mutex_unlock(&mtdblk->cache_mutex);
1da177e4 LT	331
	332	if (mtdblk->mtd->sync)
	333	mtdblk->mtd->sync(mtdblk->mtd);
	334	return 0;
	335	}
	336
	337	static void mtdblock_add_mtd(struct mtd_blktrans_ops tr, struct mtd_info mtd)
	338	{
95b93a0c	339	struct mtd_blktrans_dev dev = kzalloc(sizeof(dev), GFP_KERNEL);
1da177e4 LT	340
	341	if (!dev)
	342	return;
	343
1da177e4 LT	344	dev->mtd = mtd;
1da177e4 LT	345	dev->devnum = mtd->index;
19187672	346
1da177e4 LT	347	dev->size = mtd->size >> 9;
	348	dev->tr = tr;
	349
	350	if (!(mtd->flags & MTD_WRITEABLE))
	351	dev->readonly = 1;
	352
	353	add_mtd_blktrans_dev(dev);
	354	}
	355
	356	static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
	357	{
	358	del_mtd_blktrans_dev(dev);
	359	kfree(dev);
	360	}
	361
	362	static struct mtd_blktrans_ops mtdblock_tr = {
	363	.name = "mtdblock",
	364	.major = 31,
	365	.part_bits = 0,
19187672	366	.blksize = 512,
1da177e4 LT	367	.open = mtdblock_open,
	368	.flush = mtdblock_flush,
	369	.release = mtdblock_release,
	370	.readsect = mtdblock_readsect,
	371	.writesect = mtdblock_writesect,
	372	.add_mtd = mtdblock_add_mtd,
	373	.remove_dev = mtdblock_remove_dev,
	374	.owner = THIS_MODULE,
	375	};
	376
	377	static int __init init_mtdblock(void)
	378	{
	379	return register_mtd_blktrans(&mtdblock_tr);
	380	}
	381
	382	static void __exit cleanup_mtdblock(void)
	383	{
	384	deregister_mtd_blktrans(&mtdblock_tr);
	385	}
	386
	387	module_init(init_mtdblock);
	388	module_exit(cleanup_mtdblock);
	389
	390
	391	MODULE_LICENSE("GPL");
	392	MODULE_AUTHOR("Nicolas Pitre <nico@cam.org> et al.");
	393	MODULE_DESCRIPTION("Caching read/erase/writeback block device emulation access to MTD devices");