[deliverable/linux.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
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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/mutex.h>
#include <linux/mount.h>
#include <linux/slab.h>

/* 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 (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);
				balance_dirty_pages_ratelimited(mapping);
				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) {
		pr_err("erase failed err = %d\n", 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;

	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 (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;

	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 (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);
			balance_dirty_pages_ratelimited(mapping);
		}
		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;

	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);
		blkdev_put(dev->blkdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
	}

	kfree(dev);
}


/* FIXME: ensure that mtd->size % erase_size == 0 */
static struct block2mtd_dev *add_device(char *devname, int erase_size)
{
	const fmode_t mode = FMODE_READ | FMODE_WRITE | FMODE_EXCL;
	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 = blkdev_get_by_path(devname, mode, dev);
#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 = blkdev_get_by_dev(devt, mode, dev);
	}
#endif

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

	if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
		pr_err("attempting to use an MTD device as a block device\n");
		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.writebufsize = PAGE_SIZE;
	dev->mtd.type = MTD_RAM;
	dev->mtd.flags = MTD_CAP_RAM;
	dev->mtd._erase = block2mtd_erase;
	dev->mtd._write = block2mtd_write;
	dev->mtd._sync = block2mtd_sync;
	dev->mtd._read = block2mtd_read;
	dev->mtd.priv = dev;
	dev->mtd.owner = THIS_MODULE;

	if (mtd_device_register(&dev->mtd, NULL, 0)) {
		/* Device didn't get added, so free the entry */
		goto devinit_err;
	}
	list_add(&dev->list, &blkmtd_device_list);
	pr_info("mtd%d: [%s] erase_size = %dKiB [%d]\n",
		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;
}


#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)) {
		pr_err("parameter too long\n");
		return 0;
	}

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

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

	if (str) {
		pr_err("too many arguments\n");
		return 0;
	}

	if (!token[0]) {
		pr_err("no argument\n");
		return 0;
	}

	name = token[0];
	if (strlen(name) + 1 > 80) {
		pr_err("device name too long\n");
		return 0;
	}

	if (token[1]) {
		ret = parse_num(&erase_size, token[1]);
		if (ret) {
			pr_err("illegal erase size\n");
			return 0;
		}
	}

	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 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);
		mtd_device_unregister(&dev->mtd);
		pr_info("mtd%d: [%s] removed\n",
			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	*/
a1c06609 JP	9
	10	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	11
1da177e4 LT	12	#include <linux/module.h>
	13	#include <linux/fs.h>
	14	#include <linux/blkdev.h>
	15	#include <linux/bio.h>
	16	#include <linux/pagemap.h>
	17	#include <linux/list.h>
	18	#include <linux/init.h>
	19	#include <linux/mtd/mtd.h>
48b19268	20	#include <linux/mutex.h>
c4e7fb31	21	#include <linux/mount.h>
5a0e3ad6	22	#include <linux/slab.h>
1da177e4	23
1da177e4 LT	24	/* Info for the block device */
	25	struct block2mtd_dev {
	26	struct list_head list;
	27	struct block_device *blkdev;
	28	struct mtd_info mtd;
48b19268	29	struct mutex write_mutex;
1da177e4 LT	30	};
	31
	32
	33	/* Static info about the MTD, used in cleanup_module */
	34	static LIST_HEAD(blkmtd_device_list);
	35
	36
6fe6900e	37	static struct page page_read(struct address_space mapping, int index)
1da177e4	38	{
6fe6900e	39	return read_mapping_page(mapping, index, NULL);
1da177e4 LT	40	}
1da177e4 LT	41
1da177e4 LT	42	/* erase a specified part of the device */
	43	static int _block2mtd_erase(struct block2mtd_dev *dev, loff_t to, size_t len)
	44	{
	45	struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;
	46	struct page *page;
	47	int index = to >> PAGE_SHIFT; // page index
	48	int pages = len >> PAGE_SHIFT;
	49	u_long *p;
	50	u_long *max;
	51
	52	while (pages) {
21d31f1f	53	page = page_read(mapping, index);
1da177e4 LT	54	if (IS_ERR(page))
	55	return PTR_ERR(page);
	56
0ffb74cc JE	57	max = page_address(page) + PAGE_SIZE;
0ffb74cc JE	58	for (p=page_address(page); p<max; p++)
1da177e4 LT	59	if (*p != -1UL) {
	60	lock_page(page);
	61	memset(page_address(page), 0xff, PAGE_SIZE);
	62	set_page_dirty(page);
	63	unlock_page(page);
031da73f	64	balance_dirty_pages_ratelimited(mapping);
1da177e4 LT	65	break;
	66	}
	67
	68	page_cache_release(page);
	69	pages--;
	70	index++;
	71	}
	72	return 0;
	73	}
	74	static int block2mtd_erase(struct mtd_info mtd, struct erase_info instr)
	75	{
	76	struct block2mtd_dev *dev = mtd->priv;
	77	size_t from = instr->addr;
	78	size_t len = instr->len;
	79	int err;
	80
	81	instr->state = MTD_ERASING;
48b19268	82	mutex_lock(&dev->write_mutex);
1da177e4	83	err = _block2mtd_erase(dev, from, len);
48b19268	84	mutex_unlock(&dev->write_mutex);
1da177e4	85	if (err) {
a1c06609	86	pr_err("erase failed err = %d\n", err);
1da177e4 LT	87	instr->state = MTD_ERASE_FAILED;
	88	} else
	89	instr->state = MTD_ERASE_DONE;
	90
1da177e4 LT	91	mtd_erase_callback(instr);
	92	return err;
	93	}
	94
	95
	96	static int block2mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
	97	size_t retlen, u_char buf)
	98	{
	99	struct block2mtd_dev *dev = mtd->priv;
	100	struct page *page;
	101	int index = from >> PAGE_SHIFT;
711c11b7	102	int offset = from & (PAGE_SIZE-1);
1da177e4 LT	103	int cpylen;
1da177e4 LT	104
1da177e4 LT	105	while (len) {
	106	if ((offset + len) > PAGE_SIZE)
	107	cpylen = PAGE_SIZE - offset; // multiple pages
	108	else
	109	cpylen = len; // this page
	110	len = len - cpylen;
	111
21d31f1f	112	page = page_read(dev->blkdev->bd_inode->i_mapping, index);
1da177e4 LT	113	if (IS_ERR(page))
	114	return PTR_ERR(page);
	115
	116	memcpy(buf, page_address(page) + offset, cpylen);
	117	page_cache_release(page);
	118
	119	if (retlen)
	120	*retlen += cpylen;
	121	buf += cpylen;
	122	offset = 0;
	123	index++;
	124	}
	125	return 0;
	126	}
	127
	128
	129	/* write data to the underlying device */
	130	static int _block2mtd_write(struct block2mtd_dev dev, const u_char buf,
	131	loff_t to, size_t len, size_t *retlen)
	132	{
	133	struct page *page;
	134	struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;
	135	int index = to >> PAGE_SHIFT; // page index
	136	int offset = to & ~PAGE_MASK; // page offset
	137	int cpylen;
	138
1da177e4	139	while (len) {
e5580fbe	140	if ((offset+len) > PAGE_SIZE)
1da177e4 LT	141	cpylen = PAGE_SIZE - offset; // multiple pages
	142	else
	143	cpylen = len; // this page
	144	len = len - cpylen;
	145
21d31f1f	146	page = page_read(mapping, index);
1da177e4 LT	147	if (IS_ERR(page))
	148	return PTR_ERR(page);
	149
	150	if (memcmp(page_address(page)+offset, buf, cpylen)) {
	151	lock_page(page);
	152	memcpy(page_address(page) + offset, buf, cpylen);
	153	set_page_dirty(page);
	154	unlock_page(page);
031da73f	155	balance_dirty_pages_ratelimited(mapping);
1da177e4 LT	156	}
	157	page_cache_release(page);
	158
	159	if (retlen)
	160	*retlen += cpylen;
	161
	162	buf += cpylen;
	163	offset = 0;
	164	index++;
	165	}
	166	return 0;
	167	}
c4e7fb31 VH	168
c4e7fb31 VH	169
1da177e4 LT	170	static int block2mtd_write(struct mtd_info *mtd, loff_t to, size_t len,
	171	size_t retlen, const u_char buf)
	172	{
	173	struct block2mtd_dev *dev = mtd->priv;
	174	int err;
	175
48b19268	176	mutex_lock(&dev->write_mutex);
1da177e4	177	err = _block2mtd_write(dev, buf, to, len, retlen);
48b19268	178	mutex_unlock(&dev->write_mutex);
1da177e4 LT	179	if (err > 0)
	180	err = 0;
	181	return err;
	182	}
	183
	184
	185	/* sync the device - wait until the write queue is empty */
	186	static void block2mtd_sync(struct mtd_info *mtd)
	187	{
	188	struct block2mtd_dev *dev = mtd->priv;
	189	sync_blockdev(dev->blkdev);
	190	return;
	191	}
	192
	193
	194	static void block2mtd_free_device(struct block2mtd_dev *dev)
	195	{
	196	if (!dev)
	197	return;
	198
	199	kfree(dev->mtd.name);
	200
	201	if (dev->blkdev) {
fc0ecff6 AM	202	invalidate_mapping_pages(dev->blkdev->bd_inode->i_mapping,
fc0ecff6 AM	203	0, -1);
e525fd89	204	blkdev_put(dev->blkdev, FMODE_READ\|FMODE_WRITE\|FMODE_EXCL);
1da177e4 LT	205	}
	206
	207	kfree(dev);
	208	}
	209
	210
	211	/* FIXME: ensure that mtd->size % erase_size == 0 */
	212	static struct block2mtd_dev add_device(char devname, int erase_size)
	213	{
e525fd89	214	const fmode_t mode = FMODE_READ \| FMODE_WRITE \| FMODE_EXCL;
1da177e4 LT	215	struct block_device *bdev;
1da177e4 LT	216	struct block2mtd_dev *dev;
eadcf0d7	217	char *name;
1da177e4 LT	218
	219	if (!devname)
	220	return NULL;
	221
95b93a0c	222	dev = kzalloc(sizeof(struct block2mtd_dev), GFP_KERNEL);
1da177e4 LT	223	if (!dev)
1da177e4 LT	224	return NULL;
1da177e4 LT	225
1da177e4 LT	226	/* Get a handle on the device */
d4d77629	227	bdev = blkdev_get_by_path(devname, mode, dev);
c4e7fb31 VH	228	#ifndef MODULE
	229	if (IS_ERR(bdev)) {
	230
	231	/* We might not have rootfs mounted at this point. Try
	232	to resolve the device name by other means. */
	233
8870530a	234	dev_t devt = name_to_dev_t(devname);
e525fd89	235	if (devt)
d4d77629	236	bdev = blkdev_get_by_dev(devt, mode, dev);
c4e7fb31 VH	237	}
	238	#endif
	239
1da177e4	240	if (IS_ERR(bdev)) {
a1c06609	241	pr_err("error: cannot open device %s\n", devname);
1da177e4 LT	242	goto devinit_err;
	243	}
	244	dev->blkdev = bdev;
	245
	246	if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
a1c06609	247	pr_err("attempting to use an MTD device as a block device\n");
1da177e4 LT	248	goto devinit_err;
	249	}
	250
48b19268	251	mutex_init(&dev->write_mutex);
1da177e4 LT	252
	253	/* Setup the MTD structure */
	254	/* make the name contain the block device in */
4d682420	255	name = kasprintf(GFP_KERNEL, "block2mtd: %s", devname);
eadcf0d7	256	if (!name)
1da177e4 LT	257	goto devinit_err;
1da177e4 LT	258
eadcf0d7	259	dev->mtd.name = name;
1da177e4 LT	260
	261	dev->mtd.size = dev->blkdev->bd_inode->i_size & PAGE_MASK;
	262	dev->mtd.erasesize = erase_size;
17ffc7ba	263	dev->mtd.writesize = 1;
b6043874	264	dev->mtd.writebufsize = PAGE_SIZE;
21c8db9e	265	dev->mtd.type = MTD_RAM;
1da177e4	266	dev->mtd.flags = MTD_CAP_RAM;
3c3c10bb AB	267	dev->mtd._erase = block2mtd_erase;
3c3c10bb AB	268	dev->mtd._write = block2mtd_write;
3c3c10bb AB	269	dev->mtd._sync = block2mtd_sync;
3c3c10bb AB	270	dev->mtd._read = block2mtd_read;
1da177e4 LT	271	dev->mtd.priv = dev;
	272	dev->mtd.owner = THIS_MODULE;
	273
ee0e87b1	274	if (mtd_device_register(&dev->mtd, NULL, 0)) {
25985edc	275	/* Device didn't get added, so free the entry */
1da177e4 LT	276	goto devinit_err;
	277	}
	278	list_add(&dev->list, &blkmtd_device_list);
a1c06609 JP	279	pr_info("mtd%d: [%s] erase_size = %dKiB [%d]\n",
	280	dev->mtd.index,
	281	dev->mtd.name + strlen("block2mtd: "),
	282	dev->mtd.erasesize >> 10, dev->mtd.erasesize);
1da177e4 LT	283	return dev;
	284
	285	devinit_err:
	286	block2mtd_free_device(dev);
	287	return NULL;
	288	}
	289
	290
954c2422 JE	291	/* This function works similar to reguler strtoul. In addition, it
	292	* allows some suffixes for a more human-readable number format:
	293	* ki, Ki, kiB, KiB - multiply result with 1024
	294	* Mi, MiB - multiply result with 1024^2
	295	* Gi, GiB - multiply result with 1024^3
	296	*/
1da177e4 LT	297	static int ustrtoul(const char cp, char *endp, unsigned int base)
	298	{
	299	unsigned long result = simple_strtoul(cp, endp, base);
	300	switch (**endp) {
	301	case 'G' :
	302	result *= 1024;
	303	case 'M':
	304	result *= 1024;
954c2422	305	case 'K':
1da177e4 LT	306	case 'k':
	307	result *= 1024;
	308	/* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
954c2422 JE	309	if ((*endp)[1] == 'i') {
	310	if ((*endp)[2] == 'B')
	311	(*endp) += 3;
	312	else
	313	(*endp) += 2;
	314	}
1da177e4 LT	315	}
	316	return result;
	317	}
	318
	319
cc71229f	320	static int parse_num(size_t num, const char token)
1da177e4 LT	321	{
1da177e4 LT	322	char *endp;
cc71229f	323	size_t n;
1da177e4	324
cc71229f	325	n = (size_t) ustrtoul(token, &endp, 0);
1da177e4 LT	326	if (*endp)
	327	return -EINVAL;
	328
cc71229f	329	*num = n;
1da177e4 LT	330	return 0;
	331	}
	332
	333
1da177e4 LT	334	static inline void kill_final_newline(char *str)
	335	{
	336	char *newline = strrchr(str, '\n');
	337	if (newline && !newline[1])
	338	*newline = 0;
	339	}
	340
	341
c4e7fb31 VH	342	#ifndef MODULE
c4e7fb31 VH	343	static int block2mtd_init_called = 0;
4839f048	344	static char block2mtd_paramline[80 + 12]; /* 80 for device, 12 for erase size */
c4e7fb31 VH	345	#endif
c4e7fb31 VH	346
c4e7fb31	347	static int block2mtd_setup2(const char *val)
1da177e4	348	{
c4e7fb31	349	char buf[80 + 12]; /* 80 for device, 12 for erase size */
a6550e57	350	char *str = buf;
1da177e4 LT	351	char *token[2];
1da177e4 LT	352	char *name;
cc71229f	353	size_t erase_size = PAGE_SIZE;
1da177e4 LT	354	int i, ret;
1da177e4 LT	355
a1c06609 JP	356	if (strnlen(val, sizeof(buf)) >= sizeof(buf)) {
	357	pr_err("parameter too long\n");
	358	return 0;
	359	}
1da177e4 LT	360
	361	strcpy(str, val);
	362	kill_final_newline(str);
	363
a6550e57	364	for (i = 0; i < 2; i++)
1da177e4 LT	365	token[i] = strsep(&str, ",");
1da177e4 LT	366
a1c06609 JP	367	if (str) {
	368	pr_err("too many arguments\n");
	369	return 0;
	370	}
1da177e4	371
a1c06609 JP	372	if (!token[0]) {
	373	pr_err("no argument\n");
	374	return 0;
	375	}
1da177e4	376
c4e7fb31	377	name = token[0];
a1c06609 JP	378	if (strlen(name) + 1 > 80) {
	379	pr_err("device name too long\n");
	380	return 0;
	381	}
1da177e4 LT	382
1da177e4 LT	383	if (token[1]) {
cc71229f	384	ret = parse_num(&erase_size, token[1]);
a6550e57	385	if (ret) {
a1c06609 JP	386	pr_err("illegal erase size\n");
a1c06609 JP	387	return 0;
a6550e57	388	}
1da177e4 LT	389	}
	390
	391	add_device(name, erase_size);
	392
	393	return 0;
	394	}
	395
	396
c4e7fb31 VH	397	static int block2mtd_setup(const char val, struct kernel_param kp)
	398	{
	399	#ifdef MODULE
	400	return block2mtd_setup2(val);
	401	#else
	402	/* If more parameters are later passed in via
	403	/sys/module/block2mtd/parameters/block2mtd
	404	and block2mtd_init() has already been called,
	405	we can parse the argument now. */
	406
	407	if (block2mtd_init_called)
	408	return block2mtd_setup2(val);
	409
	410	/* During early boot stage, we only save the parameters
	411	here. We must parse them later: if the param passed
	412	from kernel boot command line, block2mtd_setup() is
	413	called so early that it is not possible to resolve
	414	the device (even kmalloc() fails). Deter that work to
	415	block2mtd_setup2(). */
	416
	417	strlcpy(block2mtd_paramline, val, sizeof(block2mtd_paramline));
	418
	419	return 0;
	420	#endif
	421	}
	422
	423
1da177e4 LT	424	module_param_call(block2mtd, block2mtd_setup, NULL, NULL, 0200);
	425	MODULE_PARM_DESC(block2mtd, "Device to use. \"block2mtd=<dev>[,<erasesize>]\"");
	426
	427	static int __init block2mtd_init(void)
	428	{
c4e7fb31	429	int ret = 0;
c4e7fb31 VH	430
	431	#ifndef MODULE
	432	if (strlen(block2mtd_paramline))
	433	ret = block2mtd_setup2(block2mtd_paramline);
	434	block2mtd_init_called = 1;
	435	#endif
	436
	437	return ret;
1da177e4 LT	438	}
	439
	440
810b7e06	441	static void block2mtd_exit(void)
1da177e4 LT	442	{
	443	struct list_head pos, next;
	444
	445	/* Remove the MTD devices */
	446	list_for_each_safe(pos, next, &blkmtd_device_list) {
	447	struct block2mtd_dev dev = list_entry(pos, typeof(dev), list);
	448	block2mtd_sync(&dev->mtd);
ee0e87b1	449	mtd_device_unregister(&dev->mtd);
a1c06609 JP	450	pr_info("mtd%d: [%s] removed\n",
	451	dev->mtd.index,
	452	dev->mtd.name + strlen("block2mtd: "));
1da177e4 LT	453	list_del(&dev->list);
	454	block2mtd_free_device(dev);
	455	}
	456	}
	457
	458
	459	module_init(block2mtd_init);
	460	module_exit(block2mtd_exit);
	461
	462	MODULE_LICENSE("GPL");
2b54aaef	463	MODULE_AUTHOR("Joern Engel <joern@lazybastard.org>");
1da177e4	464	MODULE_DESCRIPTION("Emulate an MTD using a block device");