[net-next-2.6.git] / drivers / mtd / devices / block2mtd.c

/*
 * $Id: block2mtd.c,v 1.30 2005/11/29 14:48:32 gleixner Exp $
 *
 * block2mtd.c - create an mtd from a block device
 *
 * Copyright (C) 2001,2002	Simon Evans <spse@secret.org.uk>
 * Copyright (C) 2004-2006	Jörn Engel <joern@wh.fh-wedel.de>
 *
 * Licence: GPL
 */
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/blkdev.h>
#include <linux/bio.h>
#include <linux/pagemap.h>
#include <linux/list.h>
#include <linux/init.h>
#include <linux/mtd/mtd.h>
#include <linux/buffer_head.h>
#include <linux/mutex.h>
#include <linux/mount.h>

#define VERSION "$Revision: 1.30 $"


#define ERROR(fmt, args...) printk(KERN_ERR "block2mtd: " fmt "\n" , ## args)
#define INFO(fmt, args...) printk(KERN_INFO "block2mtd: " fmt "\n" , ## args)


/* Info for the block device */
struct block2mtd_dev {
	struct list_head list;
	struct block_device *blkdev;
	struct mtd_info mtd;
	struct mutex write_mutex;
};


/* Static info about the MTD, used in cleanup_module */
static LIST_HEAD(blkmtd_device_list);


#define PAGE_READAHEAD 64
static void cache_readahead(struct address_space *mapping, int index)
{
	filler_t *filler = (filler_t*)mapping->a_ops->readpage;
	int i, pagei;
	unsigned ret = 0;
	unsigned long end_index;
	struct page *page;
	LIST_HEAD(page_pool);
	struct inode *inode = mapping->host;
	loff_t isize = i_size_read(inode);

	if (!isize) {
		INFO("iSize=0 in cache_readahead\n");
		return;
	}

	end_index = ((isize - 1) >> PAGE_CACHE_SHIFT);

	read_lock_irq(&mapping->tree_lock);
	for (i = 0; i < PAGE_READAHEAD; i++) {
		pagei = index + i;
		if (pagei > end_index) {
			INFO("Overrun end of disk in cache readahead\n");
			break;
		}
		page = radix_tree_lookup(&mapping->page_tree, pagei);
		if (page && (!i))
			break;
		if (page)
			continue;
		read_unlock_irq(&mapping->tree_lock);
		page = page_cache_alloc_cold(mapping);
		read_lock_irq(&mapping->tree_lock);
		if (!page)
			break;
		page->index = pagei;
		list_add(&page->lru, &page_pool);
		ret++;
	}
	read_unlock_irq(&mapping->tree_lock);
	if (ret)
		read_cache_pages(mapping, &page_pool, filler, NULL);
}


static struct page* page_readahead(struct address_space *mapping, int index)
{
	filler_t *filler = (filler_t*)mapping->a_ops->readpage;
	cache_readahead(mapping, index);
	return read_cache_page(mapping, index, filler, NULL);
}


/* erase a specified part of the device */
static int _block2mtd_erase(struct block2mtd_dev *dev, loff_t to, size_t len)
{
	struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;
	struct page *page;
	int index = to >> PAGE_SHIFT;	// page index
	int pages = len >> PAGE_SHIFT;
	u_long *p;
	u_long *max;

	while (pages) {
		page = page_readahead(mapping, index);
		if (!page)
			return -ENOMEM;
		if (IS_ERR(page))
			return PTR_ERR(page);

		max = (u_long*)page_address(page) + PAGE_SIZE;
		for (p=(u_long*)page_address(page); p<max; p++)
			if (*p != -1UL) {
				lock_page(page);
				memset(page_address(page), 0xff, PAGE_SIZE);
				set_page_dirty(page);
				unlock_page(page);
				break;
			}

		page_cache_release(page);
		pages--;
		index++;
	}
	return 0;
}
static int block2mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
{
	struct block2mtd_dev *dev = mtd->priv;
	size_t from = instr->addr;
	size_t len = instr->len;
	int err;

	instr->state = MTD_ERASING;
	mutex_lock(&dev->write_mutex);
	err = _block2mtd_erase(dev, from, len);
	mutex_unlock(&dev->write_mutex);
	if (err) {
		ERROR("erase failed err = %d", err);
		instr->state = MTD_ERASE_FAILED;
	} else
		instr->state = MTD_ERASE_DONE;

	instr->state = MTD_ERASE_DONE;
	mtd_erase_callback(instr);
	return err;
}


static int block2mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
		size_t *retlen, u_char *buf)
{
	struct block2mtd_dev *dev = mtd->priv;
	struct page *page;
	int index = from >> PAGE_SHIFT;
	int offset = from & (PAGE_SIZE-1);
	int cpylen;

	if (from > mtd->size)
		return -EINVAL;
	if (from + len > mtd->size)
		len = mtd->size - from;

	if (retlen)
		*retlen = 0;

	while (len) {
		if ((offset + len) > PAGE_SIZE)
			cpylen = PAGE_SIZE - offset;	// multiple pages
		else
			cpylen = len;	// this page
		len = len - cpylen;

		//      Get page
		page = page_readahead(dev->blkdev->bd_inode->i_mapping, index);
		if (!page)
			return -ENOMEM;
		if (IS_ERR(page))
			return PTR_ERR(page);

		memcpy(buf, page_address(page) + offset, cpylen);
		page_cache_release(page);

		if (retlen)
			*retlen += cpylen;
		buf += cpylen;
		offset = 0;
		index++;
	}
	return 0;
}


/* write data to the underlying device */
static int _block2mtd_write(struct block2mtd_dev *dev, const u_char *buf,
		loff_t to, size_t len, size_t *retlen)
{
	struct page *page;
	struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;
	int index = to >> PAGE_SHIFT;	// page index
	int offset = to & ~PAGE_MASK;	// page offset
	int cpylen;

	if (retlen)
		*retlen = 0;
	while (len) {
		if ((offset+len) > PAGE_SIZE)
			cpylen = PAGE_SIZE - offset;	// multiple pages
		else
			cpylen = len;			// this page
		len = len - cpylen;

		//	Get page
		page = page_readahead(mapping, index);
		if (!page)
			return -ENOMEM;
		if (IS_ERR(page))
			return PTR_ERR(page);

		if (memcmp(page_address(page)+offset, buf, cpylen)) {
			lock_page(page);
			memcpy(page_address(page) + offset, buf, cpylen);
			set_page_dirty(page);
			unlock_page(page);
		}
		page_cache_release(page);

		if (retlen)
			*retlen += cpylen;

		buf += cpylen;
		offset = 0;
		index++;
	}
	return 0;
}


static int block2mtd_write(struct mtd_info *mtd, loff_t to, size_t len,
		size_t *retlen, const u_char *buf)
{
	struct block2mtd_dev *dev = mtd->priv;
	int err;

	if (!len)
		return 0;
	if (to >= mtd->size)
		return -ENOSPC;
	if (to + len > mtd->size)
		len = mtd->size - to;

	mutex_lock(&dev->write_mutex);
	err = _block2mtd_write(dev, buf, to, len, retlen);
	mutex_unlock(&dev->write_mutex);
	if (err > 0)
		err = 0;
	return err;
}


/* sync the device - wait until the write queue is empty */
static void block2mtd_sync(struct mtd_info *mtd)
{
	struct block2mtd_dev *dev = mtd->priv;
	sync_blockdev(dev->blkdev);
	return;
}


static void block2mtd_free_device(struct block2mtd_dev *dev)
{
	if (!dev)
		return;

	kfree(dev->mtd.name);

	if (dev->blkdev) {
		invalidate_inode_pages(dev->blkdev->bd_inode->i_mapping);
		close_bdev_excl(dev->blkdev);
	}

	kfree(dev);
}


/* FIXME: ensure that mtd->size % erase_size == 0 */
static struct block2mtd_dev *add_device(char *devname, int erase_size)
{
	struct block_device *bdev;
	struct block2mtd_dev *dev;

	if (!devname)
		return NULL;

	dev = kzalloc(sizeof(struct block2mtd_dev), GFP_KERNEL);
	if (!dev)
		return NULL;

	/* Get a handle on the device */
	bdev = open_bdev_excl(devname, O_RDWR, NULL);
#ifndef MODULE
	if (IS_ERR(bdev)) {

		/* We might not have rootfs mounted at this point. Try
		   to resolve the device name by other means. */

		dev_t dev = name_to_dev_t(devname);
		if (dev != 0) {
			bdev = open_by_devnum(dev, FMODE_WRITE | FMODE_READ);
		}
	}
#endif

	if (IS_ERR(bdev)) {
		ERROR("error: cannot open device %s", devname);
		goto devinit_err;
	}
	dev->blkdev = bdev;

	if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
		ERROR("attempting to use an MTD device as a block device");
		goto devinit_err;
	}

	mutex_init(&dev->write_mutex);

	/* Setup the MTD structure */
	/* make the name contain the block device in */
	dev->mtd.name = kmalloc(sizeof("block2mtd: ") + strlen(devname),
			GFP_KERNEL);
	if (!dev->mtd.name)
		goto devinit_err;

	sprintf(dev->mtd.name, "block2mtd: %s", devname);

	dev->mtd.size = dev->blkdev->bd_inode->i_size & PAGE_MASK;
	dev->mtd.erasesize = erase_size;
	dev->mtd.writesize = 1;
	dev->mtd.type = MTD_RAM;
	dev->mtd.flags = MTD_CAP_RAM;
	dev->mtd.erase = block2mtd_erase;
	dev->mtd.write = block2mtd_write;
	dev->mtd.writev = default_mtd_writev;
	dev->mtd.sync = block2mtd_sync;
	dev->mtd.read = block2mtd_read;
	dev->mtd.priv = dev;
	dev->mtd.owner = THIS_MODULE;

	if (add_mtd_device(&dev->mtd)) {
		/* Device didnt get added, so free the entry */
		goto devinit_err;
	}
	list_add(&dev->list, &blkmtd_device_list);
	INFO("mtd%d: [%s] erase_size = %dKiB [%d]", dev->mtd.index,
			dev->mtd.name + strlen("blkmtd: "),
			dev->mtd.erasesize >> 10, dev->mtd.erasesize);
	return dev;

devinit_err:
	block2mtd_free_device(dev);
	return NULL;
}


/* This function works similar to reguler strtoul.  In addition, it
 * allows some suffixes for a more human-readable number format:
 * ki, Ki, kiB, KiB	- multiply result with 1024
 * Mi, MiB		- multiply result with 1024^2
 * Gi, GiB		- multiply result with 1024^3
 */
static int ustrtoul(const char *cp, char **endp, unsigned int base)
{
	unsigned long result = simple_strtoul(cp, endp, base);
	switch (**endp) {
	case 'G' :
		result *= 1024;
	case 'M':
		result *= 1024;
	case 'K':
	case 'k':
		result *= 1024;
	/* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
		if ((*endp)[1] == 'i') {
			if ((*endp)[2] == 'B')
				(*endp) += 3;
			else
				(*endp) += 2;
		}
	}
	return result;
}


static int parse_num(size_t *num, const char *token)
{
	char *endp;
	size_t n;

	n = (size_t) ustrtoul(token, &endp, 0);
	if (*endp)
		return -EINVAL;

	*num = n;
	return 0;
}


static inline void kill_final_newline(char *str)
{
	char *newline = strrchr(str, '\n');
	if (newline && !newline[1])
		*newline = 0;
}


#define parse_err(fmt, args...) do {		\
	ERROR("block2mtd: " fmt "\n", ## args);	\
	return 0;				\
} while (0)

#ifndef MODULE
static int block2mtd_init_called = 0;
static __initdata char block2mtd_paramline[80 + 12]; /* 80 for device, 12 for erase size */
#endif


static int block2mtd_setup2(const char *val)
{
	char buf[80 + 12]; /* 80 for device, 12 for erase size */
	char *str = buf;
	char *token[2];
	char *name;
	size_t erase_size = PAGE_SIZE;
	int i, ret;

	if (strnlen(val, sizeof(buf)) >= sizeof(buf))
		parse_err("parameter too long");

	strcpy(str, val);
	kill_final_newline(str);

	for (i = 0; i < 2; i++)
		token[i] = strsep(&str, ",");

	if (str)
		parse_err("too many arguments");

	if (!token[0])
		parse_err("no argument");

	name = token[0];
	if (strlen(name) + 1 > 80)
		parse_err("device name too long");

	if (token[1]) {
		ret = parse_num(&erase_size, token[1]);
		if (ret) {
			kfree(name);
			parse_err("illegal erase size");
		}
	}

	add_device(name, erase_size);

	return 0;
}


static int block2mtd_setup(const char *val, struct kernel_param *kp)
{
#ifdef MODULE
	return block2mtd_setup2(val);
#else
	/* If more parameters are later passed in via
	   /sys/module/block2mtd/parameters/block2mtd
	   and block2mtd_init() has already been called,
	   we can parse the argument now. */

	if (block2mtd_init_called)
		return block2mtd_setup2(val);

	/* During early boot stage, we only save the parameters
	   here. We must parse them later: if the param passed
	   from kernel boot command line, block2mtd_setup() is
	   called so early that it is not possible to resolve
	   the device (even kmalloc() fails). Deter that work to
	   block2mtd_setup2(). */

	strlcpy(block2mtd_paramline, val, sizeof(block2mtd_paramline));

	return 0;
#endif
}


module_param_call(block2mtd, block2mtd_setup, NULL, NULL, 0200);
MODULE_PARM_DESC(block2mtd, "Device to use. \"block2mtd=<dev>[,<erasesize>]\"");

static int __init block2mtd_init(void)
{
	int ret = 0;
	INFO("version " VERSION);

#ifndef MODULE
	if (strlen(block2mtd_paramline))
		ret = block2mtd_setup2(block2mtd_paramline);
	block2mtd_init_called = 1;
#endif

	return ret;
}


static void __devexit block2mtd_exit(void)
{
	struct list_head *pos, *next;

	/* Remove the MTD devices */
	list_for_each_safe(pos, next, &blkmtd_device_list) {
		struct block2mtd_dev *dev = list_entry(pos, typeof(*dev), list);
		block2mtd_sync(&dev->mtd);
		del_mtd_device(&dev->mtd);
		INFO("mtd%d: [%s] removed", dev->mtd.index,
				dev->mtd.name + strlen("blkmtd: "));
		list_del(&dev->list);
		block2mtd_free_device(dev);
	}
}


module_init(block2mtd_init);
module_exit(block2mtd_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Simon Evans <spse@secret.org.uk> and others");
MODULE_DESCRIPTION("Emulate an MTD using a block device");
Commit	Line	Data
1da177e4	1	/*
2b9175c1	2	* $Id: block2mtd.c,v 1.30 2005/11/29 14:48:32 gleixner Exp $
1da177e4 LT	3	*
	4	* block2mtd.c - create an mtd from a block device
	5	*
	6	* Copyright (C) 2001,2002 Simon Evans <spse@secret.org.uk>
151e7659	7	* Copyright (C) 2004-2006 Jörn Engel <joern@wh.fh-wedel.de>
1da177e4 LT	8	*
	9	* Licence: GPL
	10	*/
1da177e4 LT	11	#include <linux/module.h>
	12	#include <linux/fs.h>
	13	#include <linux/blkdev.h>
	14	#include <linux/bio.h>
	15	#include <linux/pagemap.h>
	16	#include <linux/list.h>
	17	#include <linux/init.h>
	18	#include <linux/mtd/mtd.h>
	19	#include <linux/buffer_head.h>
48b19268	20	#include <linux/mutex.h>
c4e7fb31	21	#include <linux/mount.h>
1da177e4	22
2b9175c1	23	#define VERSION "$Revision: 1.30 $"
1da177e4 LT	24
	25
	26	#define ERROR(fmt, args...) printk(KERN_ERR "block2mtd: " fmt "\n" , ## args)
	27	#define INFO(fmt, args...) printk(KERN_INFO "block2mtd: " fmt "\n" , ## args)
	28
	29
	30	/* Info for the block device */
	31	struct block2mtd_dev {
	32	struct list_head list;
	33	struct block_device *blkdev;
	34	struct mtd_info mtd;
48b19268	35	struct mutex write_mutex;
1da177e4 LT	36	};
	37
	38
	39	/* Static info about the MTD, used in cleanup_module */
	40	static LIST_HEAD(blkmtd_device_list);
	41
	42
	43	#define PAGE_READAHEAD 64
2b9175c1	44	static void cache_readahead(struct address_space *mapping, int index)
1da177e4 LT	45	{
	46	filler_t filler = (filler_t)mapping->a_ops->readpage;
	47	int i, pagei;
	48	unsigned ret = 0;
	49	unsigned long end_index;
	50	struct page *page;
	51	LIST_HEAD(page_pool);
	52	struct inode *inode = mapping->host;
	53	loff_t isize = i_size_read(inode);
	54
	55	if (!isize) {
	56	INFO("iSize=0 in cache_readahead\n");
	57	return;
	58	}
	59
	60	end_index = ((isize - 1) >> PAGE_CACHE_SHIFT);
	61
	62	read_lock_irq(&mapping->tree_lock);
	63	for (i = 0; i < PAGE_READAHEAD; i++) {
	64	pagei = index + i;
	65	if (pagei > end_index) {
	66	INFO("Overrun end of disk in cache readahead\n");
	67	break;
	68	}
	69	page = radix_tree_lookup(&mapping->page_tree, pagei);
	70	if (page && (!i))
	71	break;
	72	if (page)
	73	continue;
	74	read_unlock_irq(&mapping->tree_lock);
	75	page = page_cache_alloc_cold(mapping);
	76	read_lock_irq(&mapping->tree_lock);
	77	if (!page)
	78	break;
	79	page->index = pagei;
	80	list_add(&page->lru, &page_pool);
	81	ret++;
	82	}
	83	read_unlock_irq(&mapping->tree_lock);
	84	if (ret)
	85	read_cache_pages(mapping, &page_pool, filler, NULL);
	86	}
	87
	88
	89	static struct page* page_readahead(struct address_space *mapping, int index)
	90	{
	91	filler_t filler = (filler_t)mapping->a_ops->readpage;
1da177e4 LT	92	cache_readahead(mapping, index);
	93	return read_cache_page(mapping, index, filler, NULL);
	94	}
	95
	96
	97	/* erase a specified part of the device */
	98	static int _block2mtd_erase(struct block2mtd_dev *dev, loff_t to, size_t len)
	99	{
	100	struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;
	101	struct page *page;
	102	int index = to >> PAGE_SHIFT; // page index
	103	int pages = len >> PAGE_SHIFT;
	104	u_long *p;
	105	u_long *max;
	106
	107	while (pages) {
	108	page = page_readahead(mapping, index);
	109	if (!page)
	110	return -ENOMEM;
	111	if (IS_ERR(page))
	112	return PTR_ERR(page);
	113
	114	max = (u_long*)page_address(page) + PAGE_SIZE;
e5580fbe	115	for (p=(u_long*)page_address(page); p<max; p++)
1da177e4 LT	116	if (*p != -1UL) {
	117	lock_page(page);
	118	memset(page_address(page), 0xff, PAGE_SIZE);
	119	set_page_dirty(page);
	120	unlock_page(page);
	121	break;
	122	}
	123
	124	page_cache_release(page);
	125	pages--;
	126	index++;
	127	}
	128	return 0;
	129	}
	130	static int block2mtd_erase(struct mtd_info mtd, struct erase_info instr)
	131	{
	132	struct block2mtd_dev *dev = mtd->priv;
	133	size_t from = instr->addr;
	134	size_t len = instr->len;
	135	int err;
	136
	137	instr->state = MTD_ERASING;
48b19268	138	mutex_lock(&dev->write_mutex);
1da177e4	139	err = _block2mtd_erase(dev, from, len);
48b19268	140	mutex_unlock(&dev->write_mutex);
1da177e4 LT	141	if (err) {
	142	ERROR("erase failed err = %d", err);
	143	instr->state = MTD_ERASE_FAILED;
	144	} else
	145	instr->state = MTD_ERASE_DONE;
	146
	147	instr->state = MTD_ERASE_DONE;
	148	mtd_erase_callback(instr);
	149	return err;
	150	}
	151
	152
	153	static int block2mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
	154	size_t retlen, u_char buf)
	155	{
	156	struct block2mtd_dev *dev = mtd->priv;
	157	struct page *page;
	158	int index = from >> PAGE_SHIFT;
711c11b7	159	int offset = from & (PAGE_SIZE-1);
1da177e4 LT	160	int cpylen;
	161
	162	if (from > mtd->size)
	163	return -EINVAL;
	164	if (from + len > mtd->size)
	165	len = mtd->size - from;
	166
	167	if (retlen)
	168	*retlen = 0;
	169
	170	while (len) {
	171	if ((offset + len) > PAGE_SIZE)
	172	cpylen = PAGE_SIZE - offset; // multiple pages
	173	else
	174	cpylen = len; // this page
	175	len = len - cpylen;
	176
	177	// Get page
	178	page = page_readahead(dev->blkdev->bd_inode->i_mapping, index);
	179	if (!page)
	180	return -ENOMEM;
	181	if (IS_ERR(page))
	182	return PTR_ERR(page);
	183
	184	memcpy(buf, page_address(page) + offset, cpylen);
	185	page_cache_release(page);
	186
	187	if (retlen)
	188	*retlen += cpylen;
	189	buf += cpylen;
	190	offset = 0;
	191	index++;
	192	}
	193	return 0;
	194	}
	195
	196
	197	/* write data to the underlying device */
	198	static int _block2mtd_write(struct block2mtd_dev dev, const u_char buf,
	199	loff_t to, size_t len, size_t *retlen)
	200	{
	201	struct page *page;
	202	struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;
	203	int index = to >> PAGE_SHIFT; // page index
	204	int offset = to & ~PAGE_MASK; // page offset
	205	int cpylen;
	206
	207	if (retlen)
	208	*retlen = 0;
	209	while (len) {
e5580fbe	210	if ((offset+len) > PAGE_SIZE)
1da177e4 LT	211	cpylen = PAGE_SIZE - offset; // multiple pages
	212	else
	213	cpylen = len; // this page
	214	len = len - cpylen;
	215
	216	// Get page
	217	page = page_readahead(mapping, index);
	218	if (!page)
	219	return -ENOMEM;
	220	if (IS_ERR(page))
	221	return PTR_ERR(page);
	222
	223	if (memcmp(page_address(page)+offset, buf, cpylen)) {
	224	lock_page(page);
	225	memcpy(page_address(page) + offset, buf, cpylen);
	226	set_page_dirty(page);
	227	unlock_page(page);
	228	}
	229	page_cache_release(page);
	230
	231	if (retlen)
	232	*retlen += cpylen;
	233
	234	buf += cpylen;
	235	offset = 0;
	236	index++;
	237	}
	238	return 0;
	239	}
c4e7fb31 VH	240
c4e7fb31 VH	241
1da177e4 LT	242	static int block2mtd_write(struct mtd_info *mtd, loff_t to, size_t len,
	243	size_t retlen, const u_char buf)
	244	{
	245	struct block2mtd_dev *dev = mtd->priv;
	246	int err;
	247
	248	if (!len)
	249	return 0;
	250	if (to >= mtd->size)
	251	return -ENOSPC;
	252	if (to + len > mtd->size)
	253	len = mtd->size - to;
	254
48b19268	255	mutex_lock(&dev->write_mutex);
1da177e4	256	err = _block2mtd_write(dev, buf, to, len, retlen);
48b19268	257	mutex_unlock(&dev->write_mutex);
1da177e4 LT	258	if (err > 0)
	259	err = 0;
	260	return err;
	261	}
	262
	263
	264	/* sync the device - wait until the write queue is empty */
	265	static void block2mtd_sync(struct mtd_info *mtd)
	266	{
	267	struct block2mtd_dev *dev = mtd->priv;
	268	sync_blockdev(dev->blkdev);
	269	return;
	270	}
	271
	272
	273	static void block2mtd_free_device(struct block2mtd_dev *dev)
	274	{
	275	if (!dev)
	276	return;
	277
	278	kfree(dev->mtd.name);
	279
	280	if (dev->blkdev) {
	281	invalidate_inode_pages(dev->blkdev->bd_inode->i_mapping);
	282	close_bdev_excl(dev->blkdev);
	283	}
	284
	285	kfree(dev);
	286	}
	287
	288
	289	/* FIXME: ensure that mtd->size % erase_size == 0 */
	290	static struct block2mtd_dev add_device(char devname, int erase_size)
	291	{
	292	struct block_device *bdev;
	293	struct block2mtd_dev *dev;
	294
	295	if (!devname)
	296	return NULL;
	297
95b93a0c	298	dev = kzalloc(sizeof(struct block2mtd_dev), GFP_KERNEL);
1da177e4 LT	299	if (!dev)
1da177e4 LT	300	return NULL;
1da177e4 LT	301
	302	/* Get a handle on the device */
	303	bdev = open_bdev_excl(devname, O_RDWR, NULL);
c4e7fb31 VH	304	#ifndef MODULE
	305	if (IS_ERR(bdev)) {
	306
	307	/* We might not have rootfs mounted at this point. Try
	308	to resolve the device name by other means. */
	309
	310	dev_t dev = name_to_dev_t(devname);
	311	if (dev != 0) {
	312	bdev = open_by_devnum(dev, FMODE_WRITE \| FMODE_READ);
	313	}
	314	}
	315	#endif
	316
1da177e4 LT	317	if (IS_ERR(bdev)) {
	318	ERROR("error: cannot open device %s", devname);
	319	goto devinit_err;
	320	}
	321	dev->blkdev = bdev;
	322
	323	if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
	324	ERROR("attempting to use an MTD device as a block device");
	325	goto devinit_err;
	326	}
	327
48b19268	328	mutex_init(&dev->write_mutex);
1da177e4 LT	329
	330	/* Setup the MTD structure */
	331	/* make the name contain the block device in */
	332	dev->mtd.name = kmalloc(sizeof("block2mtd: ") + strlen(devname),
	333	GFP_KERNEL);
	334	if (!dev->mtd.name)
	335	goto devinit_err;
	336
	337	sprintf(dev->mtd.name, "block2mtd: %s", devname);
	338
	339	dev->mtd.size = dev->blkdev->bd_inode->i_size & PAGE_MASK;
	340	dev->mtd.erasesize = erase_size;
17ffc7ba	341	dev->mtd.writesize = 1;
21c8db9e	342	dev->mtd.type = MTD_RAM;
1da177e4 LT	343	dev->mtd.flags = MTD_CAP_RAM;
	344	dev->mtd.erase = block2mtd_erase;
	345	dev->mtd.write = block2mtd_write;
	346	dev->mtd.writev = default_mtd_writev;
	347	dev->mtd.sync = block2mtd_sync;
	348	dev->mtd.read = block2mtd_read;
1da177e4 LT	349	dev->mtd.priv = dev;
	350	dev->mtd.owner = THIS_MODULE;
	351
	352	if (add_mtd_device(&dev->mtd)) {
	353	/* Device didnt get added, so free the entry */
	354	goto devinit_err;
	355	}
	356	list_add(&dev->list, &blkmtd_device_list);
	357	INFO("mtd%d: [%s] erase_size = %dKiB [%d]", dev->mtd.index,
	358	dev->mtd.name + strlen("blkmtd: "),
	359	dev->mtd.erasesize >> 10, dev->mtd.erasesize);
	360	return dev;
	361
	362	devinit_err:
	363	block2mtd_free_device(dev);
	364	return NULL;
	365	}
	366
	367
954c2422 JE	368	/* This function works similar to reguler strtoul. In addition, it
	369	* allows some suffixes for a more human-readable number format:
	370	* ki, Ki, kiB, KiB - multiply result with 1024
	371	* Mi, MiB - multiply result with 1024^2
	372	* Gi, GiB - multiply result with 1024^3
	373	*/
1da177e4 LT	374	static int ustrtoul(const char cp, char *endp, unsigned int base)
	375	{
	376	unsigned long result = simple_strtoul(cp, endp, base);
	377	switch (**endp) {
	378	case 'G' :
	379	result *= 1024;
	380	case 'M':
	381	result *= 1024;
954c2422	382	case 'K':
1da177e4 LT	383	case 'k':
	384	result *= 1024;
	385	/* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
954c2422 JE	386	if ((*endp)[1] == 'i') {
	387	if ((*endp)[2] == 'B')
	388	(*endp) += 3;
	389	else
	390	(*endp) += 2;
	391	}
1da177e4 LT	392	}
	393	return result;
	394	}
	395
	396
cc71229f	397	static int parse_num(size_t num, const char token)
1da177e4 LT	398	{
1da177e4 LT	399	char *endp;
cc71229f	400	size_t n;
1da177e4	401
cc71229f	402	n = (size_t) ustrtoul(token, &endp, 0);
1da177e4 LT	403	if (*endp)
	404	return -EINVAL;
	405
cc71229f	406	*num = n;
1da177e4 LT	407	return 0;
	408	}
	409
	410
1da177e4 LT	411	static inline void kill_final_newline(char *str)
	412	{
	413	char *newline = strrchr(str, '\n');
	414	if (newline && !newline[1])
	415	*newline = 0;
	416	}
	417
	418
	419	#define parse_err(fmt, args...) do { \
	420	ERROR("block2mtd: " fmt "\n", ## args); \
	421	return 0; \
	422	} while (0)
	423
c4e7fb31 VH	424	#ifndef MODULE
	425	static int block2mtd_init_called = 0;
	426	static __initdata char block2mtd_paramline[80 + 12]; /* 80 for device, 12 for erase size */
	427	#endif
	428
	429
	430	static int block2mtd_setup2(const char *val)
1da177e4	431	{
c4e7fb31	432	char buf[80 + 12]; /* 80 for device, 12 for erase size */
a6550e57	433	char *str = buf;
1da177e4 LT	434	char *token[2];
1da177e4 LT	435	char *name;
cc71229f	436	size_t erase_size = PAGE_SIZE;
1da177e4 LT	437	int i, ret;
	438
	439	if (strnlen(val, sizeof(buf)) >= sizeof(buf))
	440	parse_err("parameter too long");
	441
	442	strcpy(str, val);
	443	kill_final_newline(str);
	444
a6550e57	445	for (i = 0; i < 2; i++)
1da177e4 LT	446	token[i] = strsep(&str, ",");
	447
	448	if (str)
	449	parse_err("too many arguments");
	450
	451	if (!token[0])
	452	parse_err("no argument");
	453
c4e7fb31 VH	454	name = token[0];
	455	if (strlen(name) + 1 > 80)
	456	parse_err("device name too long");
1da177e4 LT	457
1da177e4 LT	458	if (token[1]) {
cc71229f	459	ret = parse_num(&erase_size, token[1]);
a6550e57 JJ	460	if (ret) {
a6550e57 JJ	461	kfree(name);
1da177e4	462	parse_err("illegal erase size");
a6550e57	463	}
1da177e4 LT	464	}
	465
	466	add_device(name, erase_size);
	467
	468	return 0;
	469	}
	470
	471
c4e7fb31 VH	472	static int block2mtd_setup(const char val, struct kernel_param kp)
	473	{
	474	#ifdef MODULE
	475	return block2mtd_setup2(val);
	476	#else
	477	/* If more parameters are later passed in via
	478	/sys/module/block2mtd/parameters/block2mtd
	479	and block2mtd_init() has already been called,
	480	we can parse the argument now. */
	481
	482	if (block2mtd_init_called)
	483	return block2mtd_setup2(val);
	484
	485	/* During early boot stage, we only save the parameters
	486	here. We must parse them later: if the param passed
	487	from kernel boot command line, block2mtd_setup() is
	488	called so early that it is not possible to resolve
	489	the device (even kmalloc() fails). Deter that work to
	490	block2mtd_setup2(). */
	491
	492	strlcpy(block2mtd_paramline, val, sizeof(block2mtd_paramline));
	493
	494	return 0;
	495	#endif
	496	}
	497
	498
1da177e4 LT	499	module_param_call(block2mtd, block2mtd_setup, NULL, NULL, 0200);
	500	MODULE_PARM_DESC(block2mtd, "Device to use. \"block2mtd=<dev>[,<erasesize>]\"");
	501
	502	static int __init block2mtd_init(void)
	503	{
c4e7fb31	504	int ret = 0;
1da177e4	505	INFO("version " VERSION);
c4e7fb31 VH	506
	507	#ifndef MODULE
	508	if (strlen(block2mtd_paramline))
	509	ret = block2mtd_setup2(block2mtd_paramline);
	510	block2mtd_init_called = 1;
	511	#endif
	512
	513	return ret;
1da177e4 LT	514	}
	515
	516
	517	static void __devexit block2mtd_exit(void)
	518	{
	519	struct list_head pos, next;
	520
	521	/* Remove the MTD devices */
	522	list_for_each_safe(pos, next, &blkmtd_device_list) {
	523	struct block2mtd_dev dev = list_entry(pos, typeof(dev), list);
	524	block2mtd_sync(&dev->mtd);
	525	del_mtd_device(&dev->mtd);
	526	INFO("mtd%d: [%s] removed", dev->mtd.index,
	527	dev->mtd.name + strlen("blkmtd: "));
	528	list_del(&dev->list);
	529	block2mtd_free_device(dev);
	530	}
	531	}
	532
	533
	534	module_init(block2mtd_init);
	535	module_exit(block2mtd_exit);
	536
	537	MODULE_LICENSE("GPL");
	538	MODULE_AUTHOR("Simon Evans <spse@secret.org.uk> and others");
	539	MODULE_DESCRIPTION("Emulate an MTD using a block device");