[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / mtd / mtdblock.c

/*
 * Direct MTD block device access
 *
 * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
 * Copyright © 2000-2003 Nicolas Pitre <nico@fluxnic.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#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>


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;
};

static struct mutex mtdblks_lock;

/*
 * 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, 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;

	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 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;

	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->mbd.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 = 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);

	DEBUG(MTD_DEBUG_LEVEL1,"mtdblock_open\n");

	mutex_lock(&mtdblks_lock);
	if (mtdblk->count) {
		mtdblk->count++;
		mutex_unlock(&mtdblks_lock);
		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;
	}

	mutex_unlock(&mtdblks_lock);

	DEBUG(MTD_DEBUG_LEVEL1, "ok\n");

	return 0;
}

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

   	DEBUG(MTD_DEBUG_LEVEL1, "mtdblock_release\n");

	mutex_lock(&mtdblks_lock);

	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 */
		if (mbd->mtd->sync)
			mbd->mtd->sync(mbd->mtd);
		vfree(mtdblk->cache_data);
	}

	mutex_unlock(&mtdblks_lock);

	DEBUG(MTD_DEBUG_LEVEL1, "ok\n");

	return 0;
}

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);

	if (dev->mtd->sync)
		dev->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		= 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)
{
	mutex_init(&mtdblks_lock);

	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
97894cda	1	/*
1da177e4 LT	2	* Direct MTD block device access
1da177e4 LT	3	*
a1452a37 DW	4	* Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
	5	* Copyright © 2000-2003 Nicolas Pitre <nico@fluxnic.net>
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation; either version 2 of the License, or
	10	* (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, write to the Free Software
	19	* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	20	*
1da177e4 LT	21	*/
1da177e4 LT	22
1da177e4 LT	23	#include <linux/fs.h>
1da177e4 LT	24	#include <linux/init.h>
15fdc52f TG	25	#include <linux/kernel.h>
	26	#include <linux/module.h>
	27	#include <linux/sched.h>
1da177e4	28	#include <linux/slab.h>
15fdc52f	29	#include <linux/types.h>
1da177e4	30	#include <linux/vmalloc.h>
15fdc52f	31
1da177e4 LT	32	#include <linux/mtd/mtd.h>
1da177e4 LT	33	#include <linux/mtd/blktrans.h>
48b19268 IM	34	#include <linux/mutex.h>
48b19268 IM	35
1da177e4	36
cbfe93e9 BH	37	struct mtdblk_dev {
cbfe93e9 BH	38	struct mtd_blktrans_dev mbd;
1da177e4	39	int count;
48b19268	40	struct mutex cache_mutex;
1da177e4 LT	41	unsigned char *cache_data;
	42	unsigned long cache_offset;
	43	unsigned int cache_size;
	44	enum { STATE_EMPTY, STATE_CLEAN, STATE_DIRTY } cache_state;
cbfe93e9	45	};
1da177e4	46
d676c117 MK	47	static struct mutex mtdblks_lock;
d676c117 MK	48
1da177e4 LT	49	/*
1da177e4 LT	50	* Cache stuff...
97894cda	51	*
1da177e4 LT	52	* Since typical flash erasable sectors are much larger than what Linux's
	53	* buffer cache can handle, we must implement read-modify-write on flash
	54	* sectors for each block write requests. To avoid over-erasing flash sectors
	55	* and to speed things up, we locally cache a whole flash sector while it is
	56	* being written to until a different sector is required.
	57	*/
	58
	59	static void erase_callback(struct erase_info *done)
	60	{
	61	wait_queue_head_t wait_q = (wait_queue_head_t )done->priv;
	62	wake_up(wait_q);
	63	}
	64
97894cda	65	static int erase_write (struct mtd_info *mtd, unsigned long pos,
1da177e4 LT	66	int len, const char *buf)
	67	{
	68	struct erase_info erase;
	69	DECLARE_WAITQUEUE(wait, current);
	70	wait_queue_head_t wait_q;
	71	size_t retlen;
	72	int ret;
	73
	74	/*
	75	* First, let's erase the flash block.
	76	*/
	77
	78	init_waitqueue_head(&wait_q);
	79	erase.mtd = mtd;
	80	erase.callback = erase_callback;
	81	erase.addr = pos;
	82	erase.len = len;
	83	erase.priv = (u_long)&wait_q;
	84
	85	set_current_state(TASK_INTERRUPTIBLE);
	86	add_wait_queue(&wait_q, &wait);
	87
f4a43cfc	88	ret = mtd->erase(mtd, &erase);
1da177e4 LT	89	if (ret) {
	90	set_current_state(TASK_RUNNING);
	91	remove_wait_queue(&wait_q, &wait);
	92	printk (KERN_WARNING "mtdblock: erase of region [0x%lx, 0x%x] "
	93	"on \"%s\" failed\n",
	94	pos, len, mtd->name);
	95	return ret;
	96	}
	97
	98	schedule(); /* Wait for erase to finish. */
	99	remove_wait_queue(&wait_q, &wait);
	100
	101	/*
dff15509	102	* Next, write the data to flash.
1da177e4 LT	103	*/
1da177e4 LT	104
f4a43cfc	105	ret = mtd->write(mtd, pos, len, &retlen, buf);
1da177e4 LT	106	if (ret)
	107	return ret;
	108	if (retlen != len)
	109	return -EIO;
	110	return 0;
	111	}
	112
	113
	114	static int write_cached_data (struct mtdblk_dev *mtdblk)
	115	{
cbfe93e9	116	struct mtd_info *mtd = mtdblk->mbd.mtd;
1da177e4 LT	117	int ret;
	118
	119	if (mtdblk->cache_state != STATE_DIRTY)
	120	return 0;
	121
	122	DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: writing cached data for \"%s\" "
97894cda	123	"at 0x%lx, size 0x%x\n", mtd->name,
1da177e4	124	mtdblk->cache_offset, mtdblk->cache_size);
97894cda TG	125
97894cda TG	126	ret = erase_write (mtd, mtdblk->cache_offset,
1da177e4 LT	127	mtdblk->cache_size, mtdblk->cache_data);
	128	if (ret)
	129	return ret;
	130
	131	/*
25985edc	132	* Here we could arguably set the cache state to STATE_CLEAN.
97894cda TG	133	* However this could lead to inconsistency since we will not
97894cda TG	134	* be notified if this content is altered on the flash by other
1da177e4 LT	135	* means. Let's declare it empty and leave buffering tasks to
	136	* the buffer cache instead.
	137	*/
	138	mtdblk->cache_state = STATE_EMPTY;
	139	return 0;
	140	}
	141
	142
97894cda	143	static int do_cached_write (struct mtdblk_dev *mtdblk, unsigned long pos,
1da177e4 LT	144	int len, const char *buf)
1da177e4 LT	145	{
cbfe93e9	146	struct mtd_info *mtd = mtdblk->mbd.mtd;
1da177e4 LT	147	unsigned int sect_size = mtdblk->cache_size;
	148	size_t retlen;
	149	int ret;
	150
	151	DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: write on \"%s\" at 0x%lx, size 0x%x\n",
	152	mtd->name, pos, len);
97894cda	153
1da177e4	154	if (!sect_size)
f4a43cfc	155	return mtd->write(mtd, pos, len, &retlen, buf);
1da177e4 LT	156
	157	while (len > 0) {
	158	unsigned long sect_start = (pos/sect_size)*sect_size;
	159	unsigned int offset = pos - sect_start;
	160	unsigned int size = sect_size - offset;
97894cda	161	if( size > len )
1da177e4 LT	162	size = len;
	163
	164	if (size == sect_size) {
97894cda	165	/*
1da177e4 LT	166	* We are covering a whole sector. Thus there is no
	167	* need to bother with the cache while it may still be
	168	* useful for other partial writes.
	169	*/
	170	ret = erase_write (mtd, pos, size, buf);
	171	if (ret)
	172	return ret;
	173	} else {
	174	/* Partial sector: need to use the cache */
	175
	176	if (mtdblk->cache_state == STATE_DIRTY &&
	177	mtdblk->cache_offset != sect_start) {
	178	ret = write_cached_data(mtdblk);
97894cda	179	if (ret)
1da177e4 LT	180	return ret;
	181	}
	182
	183	if (mtdblk->cache_state == STATE_EMPTY \|\|
	184	mtdblk->cache_offset != sect_start) {
	185	/* fill the cache with the current sector */
	186	mtdblk->cache_state = STATE_EMPTY;
f4a43cfc TG	187	ret = mtd->read(mtd, sect_start, sect_size,
f4a43cfc TG	188	&retlen, mtdblk->cache_data);
1da177e4 LT	189	if (ret)
	190	return ret;
	191	if (retlen != sect_size)
	192	return -EIO;
	193
	194	mtdblk->cache_offset = sect_start;
	195	mtdblk->cache_size = sect_size;
	196	mtdblk->cache_state = STATE_CLEAN;
	197	}
	198
	199	/* write data to our local cache */
	200	memcpy (mtdblk->cache_data + offset, buf, size);
	201	mtdblk->cache_state = STATE_DIRTY;
	202	}
	203
	204	buf += size;
	205	pos += size;
	206	len -= size;
	207	}
	208
	209	return 0;
	210	}
	211
	212
97894cda	213	static int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos,
1da177e4 LT	214	int len, char *buf)
1da177e4 LT	215	{
cbfe93e9	216	struct mtd_info *mtd = mtdblk->mbd.mtd;
1da177e4 LT	217	unsigned int sect_size = mtdblk->cache_size;
	218	size_t retlen;
	219	int ret;
	220
97894cda	221	DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: read on \"%s\" at 0x%lx, size 0x%x\n",
1da177e4	222	mtd->name, pos, len);
97894cda	223
1da177e4	224	if (!sect_size)
f4a43cfc	225	return mtd->read(mtd, pos, len, &retlen, buf);
1da177e4 LT	226
	227	while (len > 0) {
	228	unsigned long sect_start = (pos/sect_size)*sect_size;
	229	unsigned int offset = pos - sect_start;
	230	unsigned int size = sect_size - offset;
97894cda	231	if (size > len)
1da177e4 LT	232	size = len;
	233
	234	/*
	235	* Check if the requested data is already cached
	236	* Read the requested amount of data from our internal cache if it
	237	* contains what we want, otherwise we read the data directly
	238	* from flash.
	239	*/
	240	if (mtdblk->cache_state != STATE_EMPTY &&
	241	mtdblk->cache_offset == sect_start) {
	242	memcpy (buf, mtdblk->cache_data + offset, size);
	243	} else {
f4a43cfc	244	ret = mtd->read(mtd, pos, size, &retlen, buf);
1da177e4 LT	245	if (ret)
	246	return ret;
	247	if (retlen != size)
	248	return -EIO;
	249	}
	250
	251	buf += size;
	252	pos += size;
	253	len -= size;
	254	}
	255
	256	return 0;
	257	}
	258
	259	static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
	260	unsigned long block, char *buf)
	261	{
cbfe93e9	262	struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
1da177e4 LT	263	return do_cached_read(mtdblk, block<<9, 512, buf);
	264	}
	265
	266	static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
	267	unsigned long block, char *buf)
	268	{
cbfe93e9	269	struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
1da177e4	270	if (unlikely(!mtdblk->cache_data && mtdblk->cache_size)) {
cbfe93e9	271	mtdblk->cache_data = vmalloc(mtdblk->mbd.mtd->erasesize);
1da177e4 LT	272	if (!mtdblk->cache_data)
	273	return -EINTR;
	274	/* -EINTR is not really correct, but it is the best match
	275	* documented in man 2 write for all cases. We could also
	276	* return -EAGAIN sometimes, but why bother?
	277	*/
	278	}
	279	return do_cached_write(mtdblk, block<<9, 512, buf);
	280	}
	281
	282	static int mtdblock_open(struct mtd_blktrans_dev *mbd)
	283	{
cbfe93e9	284	struct mtdblk_dev *mtdblk = container_of(mbd, struct mtdblk_dev, mbd);
1da177e4 LT	285
1da177e4 LT	286	DEBUG(MTD_DEBUG_LEVEL1,"mtdblock_open\n");
97894cda	287
d676c117	288	mutex_lock(&mtdblks_lock);
cbfe93e9 BH	289	if (mtdblk->count) {
cbfe93e9 BH	290	mtdblk->count++;
d676c117	291	mutex_unlock(&mtdblks_lock);
1da177e4 LT	292	return 0;
1da177e4 LT	293	}
97894cda	294
1da177e4	295	/* OK, it's not open. Create cache info for it */
1da177e4	296	mtdblk->count = 1;
48b19268	297	mutex_init(&mtdblk->cache_mutex);
1da177e4	298	mtdblk->cache_state = STATE_EMPTY;
cbfe93e9 BH	299	if (!(mbd->mtd->flags & MTD_NO_ERASE) && mbd->mtd->erasesize) {
cbfe93e9 BH	300	mtdblk->cache_size = mbd->mtd->erasesize;
1da177e4 LT	301	mtdblk->cache_data = NULL;
	302	}
	303
d676c117	304	mutex_unlock(&mtdblks_lock);
97894cda	305
1da177e4 LT	306	DEBUG(MTD_DEBUG_LEVEL1, "ok\n");
	307
	308	return 0;
	309	}
	310
	311	static int mtdblock_release(struct mtd_blktrans_dev *mbd)
	312	{
cbfe93e9	313	struct mtdblk_dev *mtdblk = container_of(mbd, struct mtdblk_dev, mbd);
1da177e4 LT	314
	315	DEBUG(MTD_DEBUG_LEVEL1, "mtdblock_release\n");
	316
d676c117 MK	317	mutex_lock(&mtdblks_lock);
d676c117 MK	318
48b19268	319	mutex_lock(&mtdblk->cache_mutex);
1da177e4	320	write_cached_data(mtdblk);
48b19268	321	mutex_unlock(&mtdblk->cache_mutex);
1da177e4 LT	322
1da177e4 LT	323	if (!--mtdblk->count) {
cbfe93e9 BH	324	/* It was the last usage. Free the cache */
	325	if (mbd->mtd->sync)
	326	mbd->mtd->sync(mbd->mtd);
1da177e4	327	vfree(mtdblk->cache_data);
1da177e4	328	}
d676c117 MK	329
	330	mutex_unlock(&mtdblks_lock);
	331
1da177e4 LT	332	DEBUG(MTD_DEBUG_LEVEL1, "ok\n");
	333
	334	return 0;
97894cda	335	}
1da177e4 LT	336
	337	static int mtdblock_flush(struct mtd_blktrans_dev *dev)
	338	{
cbfe93e9	339	struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
1da177e4	340
48b19268	341	mutex_lock(&mtdblk->cache_mutex);
1da177e4	342	write_cached_data(mtdblk);
48b19268	343	mutex_unlock(&mtdblk->cache_mutex);
1da177e4	344
cbfe93e9 BH	345	if (dev->mtd->sync)
cbfe93e9 BH	346	dev->mtd->sync(dev->mtd);
1da177e4 LT	347	return 0;
	348	}
	349
	350	static void mtdblock_add_mtd(struct mtd_blktrans_ops tr, struct mtd_info mtd)
	351	{
cbfe93e9	352	struct mtdblk_dev dev = kzalloc(sizeof(dev), GFP_KERNEL);
1da177e4 LT	353
	354	if (!dev)
	355	return;
	356
cbfe93e9 BH	357	dev->mbd.mtd = mtd;
cbfe93e9 BH	358	dev->mbd.devnum = mtd->index;
19187672	359
cbfe93e9 BH	360	dev->mbd.size = mtd->size >> 9;
cbfe93e9 BH	361	dev->mbd.tr = tr;
1da177e4 LT	362
1da177e4 LT	363	if (!(mtd->flags & MTD_WRITEABLE))
cbfe93e9	364	dev->mbd.readonly = 1;
1da177e4	365
298304f1 ML	366	if (add_mtd_blktrans_dev(&dev->mbd))
298304f1 ML	367	kfree(dev);
1da177e4 LT	368	}
	369
	370	static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
	371	{
	372	del_mtd_blktrans_dev(dev);
1da177e4 LT	373	}
	374
	375	static struct mtd_blktrans_ops mtdblock_tr = {
	376	.name = "mtdblock",
	377	.major = 31,
	378	.part_bits = 0,
19187672	379	.blksize = 512,
1da177e4 LT	380	.open = mtdblock_open,
	381	.flush = mtdblock_flush,
	382	.release = mtdblock_release,
	383	.readsect = mtdblock_readsect,
	384	.writesect = mtdblock_writesect,
	385	.add_mtd = mtdblock_add_mtd,
	386	.remove_dev = mtdblock_remove_dev,
	387	.owner = THIS_MODULE,
	388	};
	389
	390	static int __init init_mtdblock(void)
	391	{
d676c117 MK	392	mutex_init(&mtdblks_lock);
d676c117 MK	393
1da177e4 LT	394	return register_mtd_blktrans(&mtdblock_tr);
	395	}
	396
	397	static void __exit cleanup_mtdblock(void)
	398	{
	399	deregister_mtd_blktrans(&mtdblock_tr);
	400	}
	401
	402	module_init(init_mtdblock);
	403	module_exit(cleanup_mtdblock);
	404
	405
	406	MODULE_LICENSE("GPL");
2f82af08	407	MODULE_AUTHOR("Nicolas Pitre <nico@fluxnic.net> et al.");
1da177e4	408	MODULE_DESCRIPTION("Caching read/erase/writeback block device emulation access to MTD devices");