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

/*
 * Direct MTD block device access
 *
 * $Id: mtdblock.c,v 1.68 2005/11/07 11:14:20 gleixner Exp $
 *
 * (C) 2000-2003 Nicolas Pitre <nico@cam.org>
 * (C) 1999-2003 David Woodhouse <dwmw2@infradead.org>
 */

#include <linux/config.h>
#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 = kmalloc(sizeof(struct mtdblk_dev), GFP_KERNEL);
	if (!mtdblk)
		return -ENOMEM;

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

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

	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 = 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
97894cda	1	/*
1da177e4 LT	2	* Direct MTD block device access
1da177e4 LT	3	*
97894cda	4	* $Id: mtdblock.c,v 1.68 2005/11/07 11:14:20 gleixner Exp $
1da177e4 LT	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>
1da177e4 LT	11	#include <linux/fs.h>
1da177e4 LT	12	#include <linux/init.h>
15fdc52f TG	13	#include <linux/kernel.h>
	14	#include <linux/module.h>
	15	#include <linux/sched.h>
1da177e4	16	#include <linux/slab.h>
15fdc52f	17	#include <linux/types.h>
1da177e4	18	#include <linux/vmalloc.h>
15fdc52f	19
1da177e4 LT	20	#include <linux/mtd/mtd.h>
1da177e4 LT	21	#include <linux/mtd/blktrans.h>
48b19268 IM	22	#include <linux/mutex.h>
48b19268 IM	23
1da177e4 LT	24
	25	static struct mtdblk_dev {
	26	struct mtd_info *mtd;
	27	int count;
48b19268	28	struct mutex cache_mutex;
1da177e4 LT	29	unsigned char *cache_data;
	30	unsigned long cache_offset;
	31	unsigned int cache_size;
	32	enum { STATE_EMPTY, STATE_CLEAN, STATE_DIRTY } cache_state;
	33	} *mtdblks[MAX_MTD_DEVICES];
	34
	35	/*
	36	* Cache stuff...
97894cda	37	*
1da177e4 LT	38	* Since typical flash erasable sectors are much larger than what Linux's
	39	* buffer cache can handle, we must implement read-modify-write on flash
	40	* sectors for each block write requests. To avoid over-erasing flash sectors
	41	* and to speed things up, we locally cache a whole flash sector while it is
	42	* being written to until a different sector is required.
	43	*/
	44
	45	static void erase_callback(struct erase_info *done)
	46	{
	47	wait_queue_head_t wait_q = (wait_queue_head_t )done->priv;
	48	wake_up(wait_q);
	49	}
	50
97894cda	51	static int erase_write (struct mtd_info *mtd, unsigned long pos,
1da177e4 LT	52	int len, const char *buf)
	53	{
	54	struct erase_info erase;
	55	DECLARE_WAITQUEUE(wait, current);
	56	wait_queue_head_t wait_q;
	57	size_t retlen;
	58	int ret;
	59
	60	/*
	61	* First, let's erase the flash block.
	62	*/
	63
	64	init_waitqueue_head(&wait_q);
	65	erase.mtd = mtd;
	66	erase.callback = erase_callback;
	67	erase.addr = pos;
	68	erase.len = len;
	69	erase.priv = (u_long)&wait_q;
	70
	71	set_current_state(TASK_INTERRUPTIBLE);
	72	add_wait_queue(&wait_q, &wait);
	73
	74	ret = MTD_ERASE(mtd, &erase);
	75	if (ret) {
	76	set_current_state(TASK_RUNNING);
	77	remove_wait_queue(&wait_q, &wait);
	78	printk (KERN_WARNING "mtdblock: erase of region [0x%lx, 0x%x] "
	79	"on \"%s\" failed\n",
	80	pos, len, mtd->name);
	81	return ret;
	82	}
	83
	84	schedule(); /* Wait for erase to finish. */
	85	remove_wait_queue(&wait_q, &wait);
	86
	87	/*
	88	* Next, writhe data to flash.
	89	*/
	90
	91	ret = MTD_WRITE (mtd, pos, len, &retlen, buf);
	92	if (ret)
	93	return ret;
	94	if (retlen != len)
	95	return -EIO;
	96	return 0;
	97	}
	98
	99
	100	static int write_cached_data (struct mtdblk_dev *mtdblk)
	101	{
	102	struct mtd_info *mtd = mtdblk->mtd;
	103	int ret;
	104
	105	if (mtdblk->cache_state != STATE_DIRTY)
	106	return 0;
	107
	108	DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: writing cached data for \"%s\" "
97894cda	109	"at 0x%lx, size 0x%x\n", mtd->name,
1da177e4	110	mtdblk->cache_offset, mtdblk->cache_size);
97894cda TG	111
97894cda TG	112	ret = erase_write (mtd, mtdblk->cache_offset,
1da177e4 LT	113	mtdblk->cache_size, mtdblk->cache_data);
	114	if (ret)
	115	return ret;
	116
	117	/*
	118	* Here we could argubly set the cache state to STATE_CLEAN.
97894cda TG	119	* However this could lead to inconsistency since we will not
97894cda TG	120	* be notified if this content is altered on the flash by other
1da177e4 LT	121	* means. Let's declare it empty and leave buffering tasks to
	122	* the buffer cache instead.
	123	*/
	124	mtdblk->cache_state = STATE_EMPTY;
	125	return 0;
	126	}
	127
	128
97894cda	129	static int do_cached_write (struct mtdblk_dev *mtdblk, unsigned long pos,
1da177e4 LT	130	int len, const char *buf)
	131	{
	132	struct mtd_info *mtd = mtdblk->mtd;
	133	unsigned int sect_size = mtdblk->cache_size;
	134	size_t retlen;
	135	int ret;
	136
	137	DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: write on \"%s\" at 0x%lx, size 0x%x\n",
	138	mtd->name, pos, len);
97894cda	139
1da177e4 LT	140	if (!sect_size)
	141	return MTD_WRITE (mtd, pos, len, &retlen, buf);
	142
	143	while (len > 0) {
	144	unsigned long sect_start = (pos/sect_size)*sect_size;
	145	unsigned int offset = pos - sect_start;
	146	unsigned int size = sect_size - offset;
97894cda	147	if( size > len )
1da177e4 LT	148	size = len;
	149
	150	if (size == sect_size) {
97894cda	151	/*
1da177e4 LT	152	* We are covering a whole sector. Thus there is no
	153	* need to bother with the cache while it may still be
	154	* useful for other partial writes.
	155	*/
	156	ret = erase_write (mtd, pos, size, buf);
	157	if (ret)
	158	return ret;
	159	} else {
	160	/* Partial sector: need to use the cache */
	161
	162	if (mtdblk->cache_state == STATE_DIRTY &&
	163	mtdblk->cache_offset != sect_start) {
	164	ret = write_cached_data(mtdblk);
97894cda	165	if (ret)
1da177e4 LT	166	return ret;
	167	}
	168
	169	if (mtdblk->cache_state == STATE_EMPTY \|\|
	170	mtdblk->cache_offset != sect_start) {
	171	/* fill the cache with the current sector */
	172	mtdblk->cache_state = STATE_EMPTY;
	173	ret = MTD_READ(mtd, sect_start, sect_size, &retlen, mtdblk->cache_data);
	174	if (ret)
	175	return ret;
	176	if (retlen != sect_size)
	177	return -EIO;
	178
	179	mtdblk->cache_offset = sect_start;
	180	mtdblk->cache_size = sect_size;
	181	mtdblk->cache_state = STATE_CLEAN;
	182	}
	183
	184	/* write data to our local cache */
	185	memcpy (mtdblk->cache_data + offset, buf, size);
	186	mtdblk->cache_state = STATE_DIRTY;
	187	}
	188
	189	buf += size;
	190	pos += size;
	191	len -= size;
	192	}
	193
	194	return 0;
	195	}
	196
	197
97894cda	198	static int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos,
1da177e4 LT	199	int len, char *buf)
	200	{
	201	struct mtd_info *mtd = mtdblk->mtd;
	202	unsigned int sect_size = mtdblk->cache_size;
	203	size_t retlen;
	204	int ret;
	205
97894cda	206	DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: read on \"%s\" at 0x%lx, size 0x%x\n",
1da177e4	207	mtd->name, pos, len);
97894cda	208
1da177e4 LT	209	if (!sect_size)
	210	return MTD_READ (mtd, pos, len, &retlen, buf);
	211
	212	while (len > 0) {
	213	unsigned long sect_start = (pos/sect_size)*sect_size;
	214	unsigned int offset = pos - sect_start;
	215	unsigned int size = sect_size - offset;
97894cda	216	if (size > len)
1da177e4 LT	217	size = len;
	218
	219	/*
	220	* Check if the requested data is already cached
	221	* Read the requested amount of data from our internal cache if it
	222	* contains what we want, otherwise we read the data directly
	223	* from flash.
	224	*/
	225	if (mtdblk->cache_state != STATE_EMPTY &&
	226	mtdblk->cache_offset == sect_start) {
	227	memcpy (buf, mtdblk->cache_data + offset, size);
	228	} else {
	229	ret = MTD_READ (mtd, pos, size, &retlen, buf);
	230	if (ret)
	231	return ret;
	232	if (retlen != size)
	233	return -EIO;
	234	}
	235
	236	buf += size;
	237	pos += size;
	238	len -= size;
	239	}
	240
	241	return 0;
	242	}
	243
	244	static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
	245	unsigned long block, char *buf)
	246	{
	247	struct mtdblk_dev *mtdblk = mtdblks[dev->devnum];
	248	return do_cached_read(mtdblk, block<<9, 512, buf);
	249	}
	250
	251	static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
	252	unsigned long block, char *buf)
	253	{
	254	struct mtdblk_dev *mtdblk = mtdblks[dev->devnum];
	255	if (unlikely(!mtdblk->cache_data && mtdblk->cache_size)) {
	256	mtdblk->cache_data = vmalloc(mtdblk->mtd->erasesize);
	257	if (!mtdblk->cache_data)
	258	return -EINTR;
	259	/* -EINTR is not really correct, but it is the best match
	260	* documented in man 2 write for all cases. We could also
	261	* return -EAGAIN sometimes, but why bother?
	262	*/
	263	}
	264	return do_cached_write(mtdblk, block<<9, 512, buf);
	265	}
	266
	267	static int mtdblock_open(struct mtd_blktrans_dev *mbd)
	268	{
	269	struct mtdblk_dev *mtdblk;
	270	struct mtd_info *mtd = mbd->mtd;
	271	int dev = mbd->devnum;
	272
	273	DEBUG(MTD_DEBUG_LEVEL1,"mtdblock_open\n");
97894cda	274
1da177e4 LT	275	if (mtdblks[dev]) {
	276	mtdblks[dev]->count++;
	277	return 0;
	278	}
97894cda	279
1da177e4 LT	280	/* OK, it's not open. Create cache info for it */
	281	mtdblk = kmalloc(sizeof(struct mtdblk_dev), GFP_KERNEL);
	282	if (!mtdblk)
	283	return -ENOMEM;
	284
	285	memset(mtdblk, 0, sizeof(*mtdblk));
	286	mtdblk->count = 1;
	287	mtdblk->mtd = mtd;
	288
48b19268	289	mutex_init(&mtdblk->cache_mutex);
1da177e4	290	mtdblk->cache_state = STATE_EMPTY;
7f7c08df	291	if (mtdblk->mtd->type != MTD_RAM && mtdblk->mtd->erasesize) {
1da177e4 LT	292	mtdblk->cache_size = mtdblk->mtd->erasesize;
	293	mtdblk->cache_data = NULL;
	294	}
	295
	296	mtdblks[dev] = mtdblk;
97894cda	297
1da177e4 LT	298	DEBUG(MTD_DEBUG_LEVEL1, "ok\n");
	299
	300	return 0;
	301	}
	302
	303	static int mtdblock_release(struct mtd_blktrans_dev *mbd)
	304	{
	305	int dev = mbd->devnum;
	306	struct mtdblk_dev *mtdblk = mtdblks[dev];
	307
	308	DEBUG(MTD_DEBUG_LEVEL1, "mtdblock_release\n");
	309
48b19268	310	mutex_lock(&mtdblk->cache_mutex);
1da177e4	311	write_cached_data(mtdblk);
48b19268	312	mutex_unlock(&mtdblk->cache_mutex);
1da177e4 LT	313
	314	if (!--mtdblk->count) {
	315	/* It was the last usage. Free the device */
	316	mtdblks[dev] = NULL;
	317	if (mtdblk->mtd->sync)
	318	mtdblk->mtd->sync(mtdblk->mtd);
	319	vfree(mtdblk->cache_data);
	320	kfree(mtdblk);
	321	}
	322	DEBUG(MTD_DEBUG_LEVEL1, "ok\n");
	323
	324	return 0;
97894cda	325	}
1da177e4 LT	326
	327	static int mtdblock_flush(struct mtd_blktrans_dev *dev)
	328	{
	329	struct mtdblk_dev *mtdblk = mtdblks[dev->devnum];
	330
48b19268	331	mutex_lock(&mtdblk->cache_mutex);
1da177e4	332	write_cached_data(mtdblk);
48b19268	333	mutex_unlock(&mtdblk->cache_mutex);
1da177e4 LT	334
	335	if (mtdblk->mtd->sync)
	336	mtdblk->mtd->sync(mtdblk->mtd);
	337	return 0;
	338	}
	339
	340	static void mtdblock_add_mtd(struct mtd_blktrans_ops tr, struct mtd_info mtd)
	341	{
	342	struct mtd_blktrans_dev dev = kmalloc(sizeof(dev), GFP_KERNEL);
	343
	344	if (!dev)
	345	return;
	346
	347	memset(dev, 0, sizeof(*dev));
	348
	349	dev->mtd = mtd;
	350	dev->devnum = mtd->index;
	351	dev->blksize = 512;
	352	dev->size = mtd->size >> 9;
	353	dev->tr = tr;
	354
	355	if (!(mtd->flags & MTD_WRITEABLE))
	356	dev->readonly = 1;
	357
	358	add_mtd_blktrans_dev(dev);
	359	}
	360
	361	static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
	362	{
	363	del_mtd_blktrans_dev(dev);
	364	kfree(dev);
	365	}
	366
	367	static struct mtd_blktrans_ops mtdblock_tr = {
	368	.name = "mtdblock",
	369	.major = 31,
	370	.part_bits = 0,
	371	.open = mtdblock_open,
	372	.flush = mtdblock_flush,
	373	.release = mtdblock_release,
	374	.readsect = mtdblock_readsect,
	375	.writesect = mtdblock_writesect,
	376	.add_mtd = mtdblock_add_mtd,
	377	.remove_dev = mtdblock_remove_dev,
	378	.owner = THIS_MODULE,
	379	};
	380
	381	static int __init init_mtdblock(void)
	382	{
	383	return register_mtd_blktrans(&mtdblock_tr);
	384	}
	385
	386	static void __exit cleanup_mtdblock(void)
	387	{
	388	deregister_mtd_blktrans(&mtdblock_tr);
	389	}
	390
	391	module_init(init_mtdblock);
	392	module_exit(cleanup_mtdblock);
	393
	394
	395	MODULE_LICENSE("GPL");
	396	MODULE_AUTHOR("Nicolas Pitre <nico@cam.org> et al.");
	397	MODULE_DESCRIPTION("Caching read/erase/writeback block device emulation access to MTD devices");