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

/*
 * block2mtd.c - create an mtd from a block device
 *
 * Copyright (C) 2001,2002	Simon Evans <spse@secret.org.uk>
 * Copyright (C) 2004-2006	Joern 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>
#include <linux/slab.h>

#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);


static struct page *page_read(struct address_space *mapping, int index)
{
	return read_mapping_page(mapping, index, 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_read(mapping, index);
		if (!page)
			return -ENOMEM;
		if (IS_ERR(page))
			return PTR_ERR(page);

		max = page_address(page) + PAGE_SIZE;
		for (p=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;

	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;

		page = page_read(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;

		page = page_read(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_mapping_pages(dev->blkdev->bd_inode->i_mapping,
					0, -1);
		close_bdev_exclusive(dev->blkdev, FMODE_READ|FMODE_WRITE);
	}

	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;
	char *name;

	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_exclusive(devname, FMODE_READ|FMODE_WRITE, 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 devt = name_to_dev_t(devname);
		if (devt) {
			bdev = open_by_devnum(devt, 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 */
	name = kasprintf(GFP_KERNEL, "block2mtd: %s", devname);
	if (!name)
		goto devinit_err;

	dev->mtd.name = name;

	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("block2mtd: "),
			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(fmt, ## args);		\
	return 0;			\
} while (0)

#ifndef MODULE
static int block2mtd_init_called = 0;
static 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) {
			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;

#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("block2mtd: "));
		list_del(&dev->list);
		block2mtd_free_device(dev);
	}
}


module_init(block2mtd_init);
module_exit(block2mtd_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Joern Engel <joern@lazybastard.org>");
MODULE_DESCRIPTION("Emulate an MTD using a block device");
Commit	Line	Data
1da177e4	1	/*
1da177e4 LT	2	* block2mtd.c - create an mtd from a block device
	3	*
	4	* Copyright (C) 2001,2002 Simon Evans <spse@secret.org.uk>
2b54aaef	5	* Copyright (C) 2004-2006 Joern Engel <joern@wh.fh-wedel.de>
1da177e4 LT	6	*
	7	* Licence: GPL
	8	*/
1da177e4 LT	9	#include <linux/module.h>
	10	#include <linux/fs.h>
	11	#include <linux/blkdev.h>
	12	#include <linux/bio.h>
	13	#include <linux/pagemap.h>
	14	#include <linux/list.h>
	15	#include <linux/init.h>
	16	#include <linux/mtd/mtd.h>
	17	#include <linux/buffer_head.h>
48b19268	18	#include <linux/mutex.h>
c4e7fb31	19	#include <linux/mount.h>
5a0e3ad6	20	#include <linux/slab.h>
1da177e4	21
1da177e4 LT	22	#define ERROR(fmt, args...) printk(KERN_ERR "block2mtd: " fmt "\n" , ## args)
	23	#define INFO(fmt, args...) printk(KERN_INFO "block2mtd: " fmt "\n" , ## args)
	24
	25
	26	/* Info for the block device */
	27	struct block2mtd_dev {
	28	struct list_head list;
	29	struct block_device *blkdev;
	30	struct mtd_info mtd;
48b19268	31	struct mutex write_mutex;
1da177e4 LT	32	};
	33
	34
	35	/* Static info about the MTD, used in cleanup_module */
	36	static LIST_HEAD(blkmtd_device_list);
	37
	38
6fe6900e	39	static struct page page_read(struct address_space mapping, int index)
1da177e4	40	{
6fe6900e	41	return read_mapping_page(mapping, index, NULL);
1da177e4 LT	42	}
1da177e4 LT	43
1da177e4 LT	44	/* erase a specified part of the device */
	45	static int _block2mtd_erase(struct block2mtd_dev *dev, loff_t to, size_t len)
	46	{
	47	struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;
	48	struct page *page;
	49	int index = to >> PAGE_SHIFT; // page index
	50	int pages = len >> PAGE_SHIFT;
	51	u_long *p;
	52	u_long *max;
	53
	54	while (pages) {
21d31f1f	55	page = page_read(mapping, index);
1da177e4 LT	56	if (!page)
	57	return -ENOMEM;
	58	if (IS_ERR(page))
	59	return PTR_ERR(page);
	60
0ffb74cc JE	61	max = page_address(page) + PAGE_SIZE;
0ffb74cc JE	62	for (p=page_address(page); p<max; p++)
1da177e4 LT	63	if (*p != -1UL) {
	64	lock_page(page);
	65	memset(page_address(page), 0xff, PAGE_SIZE);
	66	set_page_dirty(page);
	67	unlock_page(page);
	68	break;
	69	}
	70
	71	page_cache_release(page);
	72	pages--;
	73	index++;
	74	}
	75	return 0;
	76	}
	77	static int block2mtd_erase(struct mtd_info mtd, struct erase_info instr)
	78	{
	79	struct block2mtd_dev *dev = mtd->priv;
	80	size_t from = instr->addr;
	81	size_t len = instr->len;
	82	int err;
	83
	84	instr->state = MTD_ERASING;
48b19268	85	mutex_lock(&dev->write_mutex);
1da177e4	86	err = _block2mtd_erase(dev, from, len);
48b19268	87	mutex_unlock(&dev->write_mutex);
1da177e4 LT	88	if (err) {
	89	ERROR("erase failed err = %d", err);
	90	instr->state = MTD_ERASE_FAILED;
	91	} else
	92	instr->state = MTD_ERASE_DONE;
	93
1da177e4 LT	94	mtd_erase_callback(instr);
	95	return err;
	96	}
	97
	98
	99	static int block2mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
	100	size_t retlen, u_char buf)
	101	{
	102	struct block2mtd_dev *dev = mtd->priv;
	103	struct page *page;
	104	int index = from >> PAGE_SHIFT;
711c11b7	105	int offset = from & (PAGE_SIZE-1);
1da177e4 LT	106	int cpylen;
	107
	108	if (from > mtd->size)
	109	return -EINVAL;
	110	if (from + len > mtd->size)
	111	len = mtd->size - from;
	112
	113	if (retlen)
	114	*retlen = 0;
	115
	116	while (len) {
	117	if ((offset + len) > PAGE_SIZE)
	118	cpylen = PAGE_SIZE - offset; // multiple pages
	119	else
	120	cpylen = len; // this page
	121	len = len - cpylen;
	122
21d31f1f	123	page = page_read(dev->blkdev->bd_inode->i_mapping, index);
1da177e4 LT	124	if (!page)
	125	return -ENOMEM;
	126	if (IS_ERR(page))
	127	return PTR_ERR(page);
	128
	129	memcpy(buf, page_address(page) + offset, cpylen);
	130	page_cache_release(page);
	131
	132	if (retlen)
	133	*retlen += cpylen;
	134	buf += cpylen;
	135	offset = 0;
	136	index++;
	137	}
	138	return 0;
	139	}
	140
	141
	142	/* write data to the underlying device */
	143	static int _block2mtd_write(struct block2mtd_dev dev, const u_char buf,
	144	loff_t to, size_t len, size_t *retlen)
	145	{
	146	struct page *page;
	147	struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;
	148	int index = to >> PAGE_SHIFT; // page index
	149	int offset = to & ~PAGE_MASK; // page offset
	150	int cpylen;
	151
	152	if (retlen)
	153	*retlen = 0;
	154	while (len) {
e5580fbe	155	if ((offset+len) > PAGE_SIZE)
1da177e4 LT	156	cpylen = PAGE_SIZE - offset; // multiple pages
	157	else
	158	cpylen = len; // this page
	159	len = len - cpylen;
	160
21d31f1f	161	page = page_read(mapping, index);
1da177e4 LT	162	if (!page)
	163	return -ENOMEM;
	164	if (IS_ERR(page))
	165	return PTR_ERR(page);
	166
	167	if (memcmp(page_address(page)+offset, buf, cpylen)) {
	168	lock_page(page);
	169	memcpy(page_address(page) + offset, buf, cpylen);
	170	set_page_dirty(page);
	171	unlock_page(page);
	172	}
	173	page_cache_release(page);
	174
	175	if (retlen)
	176	*retlen += cpylen;
	177
	178	buf += cpylen;
	179	offset = 0;
	180	index++;
	181	}
	182	return 0;
	183	}
c4e7fb31 VH	184
c4e7fb31 VH	185
1da177e4 LT	186	static int block2mtd_write(struct mtd_info *mtd, loff_t to, size_t len,
	187	size_t retlen, const u_char buf)
	188	{
	189	struct block2mtd_dev *dev = mtd->priv;
	190	int err;
	191
	192	if (!len)
	193	return 0;
	194	if (to >= mtd->size)
	195	return -ENOSPC;
	196	if (to + len > mtd->size)
	197	len = mtd->size - to;
	198
48b19268	199	mutex_lock(&dev->write_mutex);
1da177e4	200	err = _block2mtd_write(dev, buf, to, len, retlen);
48b19268	201	mutex_unlock(&dev->write_mutex);
1da177e4 LT	202	if (err > 0)
	203	err = 0;
	204	return err;
	205	}
	206
	207
	208	/* sync the device - wait until the write queue is empty */
	209	static void block2mtd_sync(struct mtd_info *mtd)
	210	{
	211	struct block2mtd_dev *dev = mtd->priv;
	212	sync_blockdev(dev->blkdev);
	213	return;
	214	}
	215
	216
	217	static void block2mtd_free_device(struct block2mtd_dev *dev)
	218	{
	219	if (!dev)
	220	return;
	221
	222	kfree(dev->mtd.name);
	223
	224	if (dev->blkdev) {
fc0ecff6 AM	225	invalidate_mapping_pages(dev->blkdev->bd_inode->i_mapping,
fc0ecff6 AM	226	0, -1);
30c40d2c	227	close_bdev_exclusive(dev->blkdev, FMODE_READ\|FMODE_WRITE);
1da177e4 LT	228	}
	229
	230	kfree(dev);
	231	}
	232
	233
	234	/* FIXME: ensure that mtd->size % erase_size == 0 */
	235	static struct block2mtd_dev add_device(char devname, int erase_size)
	236	{
	237	struct block_device *bdev;
	238	struct block2mtd_dev *dev;
eadcf0d7	239	char *name;
1da177e4 LT	240
	241	if (!devname)
	242	return NULL;
	243
95b93a0c	244	dev = kzalloc(sizeof(struct block2mtd_dev), GFP_KERNEL);
1da177e4 LT	245	if (!dev)
1da177e4 LT	246	return NULL;
1da177e4 LT	247
1da177e4 LT	248	/* Get a handle on the device */
30c40d2c	249	bdev = open_bdev_exclusive(devname, FMODE_READ\|FMODE_WRITE, NULL);
c4e7fb31 VH	250	#ifndef MODULE
	251	if (IS_ERR(bdev)) {
	252
	253	/* We might not have rootfs mounted at this point. Try
	254	to resolve the device name by other means. */
	255
8870530a JE	256	dev_t devt = name_to_dev_t(devname);
	257	if (devt) {
	258	bdev = open_by_devnum(devt, FMODE_WRITE \| FMODE_READ);
c4e7fb31 VH	259	}
	260	}
	261	#endif
	262
1da177e4 LT	263	if (IS_ERR(bdev)) {
	264	ERROR("error: cannot open device %s", devname);
	265	goto devinit_err;
	266	}
	267	dev->blkdev = bdev;
	268
	269	if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
	270	ERROR("attempting to use an MTD device as a block device");
	271	goto devinit_err;
	272	}
	273
48b19268	274	mutex_init(&dev->write_mutex);
1da177e4 LT	275
	276	/* Setup the MTD structure */
	277	/* make the name contain the block device in */
4d682420	278	name = kasprintf(GFP_KERNEL, "block2mtd: %s", devname);
eadcf0d7	279	if (!name)
1da177e4 LT	280	goto devinit_err;
1da177e4 LT	281
eadcf0d7	282	dev->mtd.name = name;
1da177e4 LT	283
	284	dev->mtd.size = dev->blkdev->bd_inode->i_size & PAGE_MASK;
	285	dev->mtd.erasesize = erase_size;
17ffc7ba	286	dev->mtd.writesize = 1;
21c8db9e	287	dev->mtd.type = MTD_RAM;
1da177e4 LT	288	dev->mtd.flags = MTD_CAP_RAM;
	289	dev->mtd.erase = block2mtd_erase;
	290	dev->mtd.write = block2mtd_write;
	291	dev->mtd.writev = default_mtd_writev;
	292	dev->mtd.sync = block2mtd_sync;
	293	dev->mtd.read = block2mtd_read;
1da177e4 LT	294	dev->mtd.priv = dev;
	295	dev->mtd.owner = THIS_MODULE;
	296
	297	if (add_mtd_device(&dev->mtd)) {
	298	/* Device didnt get added, so free the entry */
	299	goto devinit_err;
	300	}
	301	list_add(&dev->list, &blkmtd_device_list);
	302	INFO("mtd%d: [%s] erase_size = %dKiB [%d]", dev->mtd.index,
0bc88c59	303	dev->mtd.name + strlen("block2mtd: "),
1da177e4 LT	304	dev->mtd.erasesize >> 10, dev->mtd.erasesize);
	305	return dev;
	306
	307	devinit_err:
	308	block2mtd_free_device(dev);
	309	return NULL;
	310	}
	311
	312
954c2422 JE	313	/* This function works similar to reguler strtoul. In addition, it
	314	* allows some suffixes for a more human-readable number format:
	315	* ki, Ki, kiB, KiB - multiply result with 1024
	316	* Mi, MiB - multiply result with 1024^2
	317	* Gi, GiB - multiply result with 1024^3
	318	*/
1da177e4 LT	319	static int ustrtoul(const char cp, char *endp, unsigned int base)
	320	{
	321	unsigned long result = simple_strtoul(cp, endp, base);
	322	switch (**endp) {
	323	case 'G' :
	324	result *= 1024;
	325	case 'M':
	326	result *= 1024;
954c2422	327	case 'K':
1da177e4 LT	328	case 'k':
	329	result *= 1024;
	330	/* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
954c2422 JE	331	if ((*endp)[1] == 'i') {
	332	if ((*endp)[2] == 'B')
	333	(*endp) += 3;
	334	else
	335	(*endp) += 2;
	336	}
1da177e4 LT	337	}
	338	return result;
	339	}
	340
	341
cc71229f	342	static int parse_num(size_t num, const char token)
1da177e4 LT	343	{
1da177e4 LT	344	char *endp;
cc71229f	345	size_t n;
1da177e4	346
cc71229f	347	n = (size_t) ustrtoul(token, &endp, 0);
1da177e4 LT	348	if (*endp)
	349	return -EINVAL;
	350
cc71229f	351	*num = n;
1da177e4 LT	352	return 0;
	353	}
	354
	355
1da177e4 LT	356	static inline void kill_final_newline(char *str)
	357	{
	358	char *newline = strrchr(str, '\n');
	359	if (newline && !newline[1])
	360	*newline = 0;
	361	}
	362
	363
0bc88c59 SC	364	#define parse_err(fmt, args...) do { \
	365	ERROR(fmt, ## args); \
	366	return 0; \
1da177e4 LT	367	} while (0)
1da177e4 LT	368
c4e7fb31 VH	369	#ifndef MODULE
c4e7fb31 VH	370	static int block2mtd_init_called = 0;
4839f048	371	static char block2mtd_paramline[80 + 12]; /* 80 for device, 12 for erase size */
c4e7fb31 VH	372	#endif
	373
	374
	375	static int block2mtd_setup2(const char *val)
1da177e4	376	{
c4e7fb31	377	char buf[80 + 12]; /* 80 for device, 12 for erase size */
a6550e57	378	char *str = buf;
1da177e4 LT	379	char *token[2];
1da177e4 LT	380	char *name;
cc71229f	381	size_t erase_size = PAGE_SIZE;
1da177e4 LT	382	int i, ret;
	383
	384	if (strnlen(val, sizeof(buf)) >= sizeof(buf))
	385	parse_err("parameter too long");
	386
	387	strcpy(str, val);
	388	kill_final_newline(str);
	389
a6550e57	390	for (i = 0; i < 2; i++)
1da177e4 LT	391	token[i] = strsep(&str, ",");
	392
	393	if (str)
	394	parse_err("too many arguments");
	395
	396	if (!token[0])
	397	parse_err("no argument");
	398
c4e7fb31 VH	399	name = token[0];
	400	if (strlen(name) + 1 > 80)
	401	parse_err("device name too long");
1da177e4 LT	402
1da177e4 LT	403	if (token[1]) {
cc71229f	404	ret = parse_num(&erase_size, token[1]);
a6550e57	405	if (ret) {
1da177e4	406	parse_err("illegal erase size");
a6550e57	407	}
1da177e4 LT	408	}
	409
	410	add_device(name, erase_size);
	411
	412	return 0;
	413	}
	414
	415
c4e7fb31 VH	416	static int block2mtd_setup(const char val, struct kernel_param kp)
	417	{
	418	#ifdef MODULE
	419	return block2mtd_setup2(val);
	420	#else
	421	/* If more parameters are later passed in via
	422	/sys/module/block2mtd/parameters/block2mtd
	423	and block2mtd_init() has already been called,
	424	we can parse the argument now. */
	425
	426	if (block2mtd_init_called)
	427	return block2mtd_setup2(val);
	428
	429	/* During early boot stage, we only save the parameters
	430	here. We must parse them later: if the param passed
	431	from kernel boot command line, block2mtd_setup() is
	432	called so early that it is not possible to resolve
	433	the device (even kmalloc() fails). Deter that work to
	434	block2mtd_setup2(). */
	435
	436	strlcpy(block2mtd_paramline, val, sizeof(block2mtd_paramline));
	437
	438	return 0;
	439	#endif
	440	}
	441
	442
1da177e4 LT	443	module_param_call(block2mtd, block2mtd_setup, NULL, NULL, 0200);
	444	MODULE_PARM_DESC(block2mtd, "Device to use. \"block2mtd=<dev>[,<erasesize>]\"");
	445
	446	static int __init block2mtd_init(void)
	447	{
c4e7fb31	448	int ret = 0;
c4e7fb31 VH	449
	450	#ifndef MODULE
	451	if (strlen(block2mtd_paramline))
	452	ret = block2mtd_setup2(block2mtd_paramline);
	453	block2mtd_init_called = 1;
	454	#endif
	455
	456	return ret;
1da177e4 LT	457	}
	458
	459
	460	static void __devexit block2mtd_exit(void)
	461	{
	462	struct list_head pos, next;
	463
	464	/* Remove the MTD devices */
	465	list_for_each_safe(pos, next, &blkmtd_device_list) {
	466	struct block2mtd_dev dev = list_entry(pos, typeof(dev), list);
	467	block2mtd_sync(&dev->mtd);
	468	del_mtd_device(&dev->mtd);
	469	INFO("mtd%d: [%s] removed", dev->mtd.index,
0bc88c59	470	dev->mtd.name + strlen("block2mtd: "));
1da177e4 LT	471	list_del(&dev->list);
	472	block2mtd_free_device(dev);
	473	}
	474	}
	475
	476
	477	module_init(block2mtd_init);
	478	module_exit(block2mtd_exit);
	479
	480	MODULE_LICENSE("GPL");
2b54aaef	481	MODULE_AUTHOR("Joern Engel <joern@lazybastard.org>");
1da177e4	482	MODULE_DESCRIPTION("Emulate an MTD using a block device");