[mirror_ubuntu-artful-kernel.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

/*
 * When the first attempt at device initialization fails, we may need to
 * wait a little bit and retry. This timeout, by default 3 seconds, gives
 * device time to start up. Required on BCM2708 and a few other chipsets.
 */
#define MTD_DEFAULT_TIMEOUT	3

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.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>
#include <linux/major.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;
			}

		put_page(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);
		put_page(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);
		}
		put_page(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);
}


static struct block2mtd_dev *add_device(char *devname, int erase_size,
		int timeout)
{
#ifndef MODULE
	int i;
#endif
	const fmode_t mode = FMODE_READ | FMODE_WRITE | FMODE_EXCL;
	struct block_device *bdev = ERR_PTR(-ENODEV);
	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
	/*
	 * We might not have the root device mounted at this point.
	 * Try to resolve the device name by other means.
	 */
	for (i = 0; IS_ERR(bdev) && i <= timeout; i++) {
		dev_t devt;

		if (i)
			/*
			 * Calling wait_for_device_probe in the first loop
			 * was not enough, sleep for a bit in subsequent
			 * go-arounds.
			 */
			msleep(1000);
		wait_for_device_probe();

		devt = name_to_dev_t(devname);
		if (!devt)
			continue;
		bdev = blkdev_get_by_dev(devt, mode, dev);
	}
#endif

	if (IS_ERR(bdev)) {
		pr_err("error: cannot open device %s\n", devname);
		goto err_free_block2mtd;
	}
	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 err_free_block2mtd;
	}

	if ((long)dev->blkdev->bd_inode->i_size % erase_size) {
		pr_err("erasesize must be a divisor of device size\n");
		goto err_free_block2mtd;
	}

	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 err_destroy_mutex;

	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 err_destroy_mutex;
	}

	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;

err_destroy_mutex:
	mutex_destroy(&dev->write_mutex);
err_free_block2mtd:
	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;
/* 80 for device, 12 for erase size */
static char block2mtd_paramline[80 + 12];
#endif

static int block2mtd_setup2(const char *val)
{
	/* 80 for device, 12 for erase size, 80 for name, 8 for timeout */
	char buf[80 + 12 + 80 + 8];
	char *str = buf;
	char *token[2];
	char *name;
	size_t erase_size = PAGE_SIZE;
	unsigned long timeout = MTD_DEFAULT_TIMEOUT;
	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, timeout);

	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);
		mutex_destroy(&dev->write_mutex);
		pr_info("mtd%d: [%s] removed\n",
			dev->mtd.index,
			dev->mtd.name + strlen("block2mtd: "));
		list_del(&dev->list);
		block2mtd_free_device(dev);
	}
}

late_initcall(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
d6a3f017 FF	12	/*
	13	* When the first attempt at device initialization fails, we may need to
	14	* wait a little bit and retry. This timeout, by default 3 seconds, gives
	15	* device time to start up. Required on BCM2708 and a few other chipsets.
	16	*/
	17	#define MTD_DEFAULT_TIMEOUT 3
	18
1da177e4	19	#include <linux/module.h>
d6a3f017	20	#include <linux/delay.h>
1da177e4 LT	21	#include <linux/fs.h>
1da177e4 LT	22	#include <linux/blkdev.h>
66114cad	23	#include <linux/backing-dev.h>
1da177e4 LT	24	#include <linux/bio.h>
	25	#include <linux/pagemap.h>
	26	#include <linux/list.h>
	27	#include <linux/init.h>
	28	#include <linux/mtd/mtd.h>
48b19268	29	#include <linux/mutex.h>
c4e7fb31	30	#include <linux/mount.h>
5a0e3ad6	31	#include <linux/slab.h>
f83c3838	32	#include <linux/major.h>
1da177e4	33
1da177e4 LT	34	/* Info for the block device */
	35	struct block2mtd_dev {
	36	struct list_head list;
	37	struct block_device *blkdev;
	38	struct mtd_info mtd;
48b19268	39	struct mutex write_mutex;
1da177e4 LT	40	};
	41
	42
	43	/* Static info about the MTD, used in cleanup_module */
	44	static LIST_HEAD(blkmtd_device_list);
	45
	46
6fe6900e	47	static struct page page_read(struct address_space mapping, int index)
1da177e4	48	{
6fe6900e	49	return read_mapping_page(mapping, index, NULL);
1da177e4 LT	50	}
1da177e4 LT	51
1da177e4 LT	52	/* erase a specified part of the device */
	53	static int _block2mtd_erase(struct block2mtd_dev *dev, loff_t to, size_t len)
	54	{
	55	struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;
	56	struct page *page;
	57	int index = to >> PAGE_SHIFT; // page index
	58	int pages = len >> PAGE_SHIFT;
	59	u_long *p;
	60	u_long *max;
	61
	62	while (pages) {
21d31f1f	63	page = page_read(mapping, index);
1da177e4 LT	64	if (IS_ERR(page))
	65	return PTR_ERR(page);
	66
0ffb74cc JE	67	max = page_address(page) + PAGE_SIZE;
0ffb74cc JE	68	for (p=page_address(page); p<max; p++)
1da177e4 LT	69	if (*p != -1UL) {
	70	lock_page(page);
	71	memset(page_address(page), 0xff, PAGE_SIZE);
	72	set_page_dirty(page);
	73	unlock_page(page);
031da73f	74	balance_dirty_pages_ratelimited(mapping);
1da177e4 LT	75	break;
	76	}
	77
09cbfeaf	78	put_page(page);
1da177e4 LT	79	pages--;
	80	index++;
	81	}
	82	return 0;
	83	}
	84	static int block2mtd_erase(struct mtd_info mtd, struct erase_info instr)
	85	{
	86	struct block2mtd_dev *dev = mtd->priv;
	87	size_t from = instr->addr;
	88	size_t len = instr->len;
	89	int err;
	90
	91	instr->state = MTD_ERASING;
48b19268	92	mutex_lock(&dev->write_mutex);
1da177e4	93	err = _block2mtd_erase(dev, from, len);
48b19268	94	mutex_unlock(&dev->write_mutex);
1da177e4	95	if (err) {
a1c06609	96	pr_err("erase failed err = %d\n", err);
1da177e4 LT	97	instr->state = MTD_ERASE_FAILED;
	98	} else
	99	instr->state = MTD_ERASE_DONE;
	100
1da177e4 LT	101	mtd_erase_callback(instr);
	102	return err;
	103	}
	104
	105
	106	static int block2mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
	107	size_t retlen, u_char buf)
	108	{
	109	struct block2mtd_dev *dev = mtd->priv;
	110	struct page *page;
	111	int index = from >> PAGE_SHIFT;
711c11b7	112	int offset = from & (PAGE_SIZE-1);
1da177e4 LT	113	int cpylen;
1da177e4 LT	114
1da177e4 LT	115	while (len) {
	116	if ((offset + len) > PAGE_SIZE)
	117	cpylen = PAGE_SIZE - offset; // multiple pages
	118	else
	119	cpylen = len; // this page
	120	len = len - cpylen;
	121
21d31f1f	122	page = page_read(dev->blkdev->bd_inode->i_mapping, index);
1da177e4 LT	123	if (IS_ERR(page))
	124	return PTR_ERR(page);
	125
	126	memcpy(buf, page_address(page) + offset, cpylen);
09cbfeaf	127	put_page(page);
1da177e4 LT	128
	129	if (retlen)
	130	*retlen += cpylen;
	131	buf += cpylen;
	132	offset = 0;
	133	index++;
	134	}
	135	return 0;
	136	}
	137
	138
	139	/* write data to the underlying device */
	140	static int _block2mtd_write(struct block2mtd_dev dev, const u_char buf,
	141	loff_t to, size_t len, size_t *retlen)
	142	{
	143	struct page *page;
	144	struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;
	145	int index = to >> PAGE_SHIFT; // page index
	146	int offset = to & ~PAGE_MASK; // page offset
	147	int cpylen;
	148
1da177e4	149	while (len) {
e5580fbe	150	if ((offset+len) > PAGE_SIZE)
1da177e4 LT	151	cpylen = PAGE_SIZE - offset; // multiple pages
	152	else
	153	cpylen = len; // this page
	154	len = len - cpylen;
	155
21d31f1f	156	page = page_read(mapping, index);
1da177e4 LT	157	if (IS_ERR(page))
	158	return PTR_ERR(page);
	159
	160	if (memcmp(page_address(page)+offset, buf, cpylen)) {
	161	lock_page(page);
	162	memcpy(page_address(page) + offset, buf, cpylen);
	163	set_page_dirty(page);
	164	unlock_page(page);
031da73f	165	balance_dirty_pages_ratelimited(mapping);
1da177e4	166	}
09cbfeaf	167	put_page(page);
1da177e4 LT	168
	169	if (retlen)
	170	*retlen += cpylen;
	171
	172	buf += cpylen;
	173	offset = 0;
	174	index++;
	175	}
	176	return 0;
	177	}
c4e7fb31 VH	178
c4e7fb31 VH	179
1da177e4 LT	180	static int block2mtd_write(struct mtd_info *mtd, loff_t to, size_t len,
	181	size_t retlen, const u_char buf)
	182	{
	183	struct block2mtd_dev *dev = mtd->priv;
	184	int err;
	185
48b19268	186	mutex_lock(&dev->write_mutex);
1da177e4	187	err = _block2mtd_write(dev, buf, to, len, retlen);
48b19268	188	mutex_unlock(&dev->write_mutex);
1da177e4 LT	189	if (err > 0)
	190	err = 0;
	191	return err;
	192	}
	193
	194
	195	/* sync the device - wait until the write queue is empty */
	196	static void block2mtd_sync(struct mtd_info *mtd)
	197	{
	198	struct block2mtd_dev *dev = mtd->priv;
	199	sync_blockdev(dev->blkdev);
	200	return;
	201	}
	202
	203
	204	static void block2mtd_free_device(struct block2mtd_dev *dev)
	205	{
	206	if (!dev)
	207	return;
	208
	209	kfree(dev->mtd.name);
	210
	211	if (dev->blkdev) {
fc0ecff6 AM	212	invalidate_mapping_pages(dev->blkdev->bd_inode->i_mapping,
fc0ecff6 AM	213	0, -1);
e525fd89	214	blkdev_put(dev->blkdev, FMODE_READ\|FMODE_WRITE\|FMODE_EXCL);
1da177e4 LT	215	}
	216
	217	kfree(dev);
	218	}
	219
	220
d6a3f017 FF	221	static struct block2mtd_dev add_device(char devname, int erase_size,
d6a3f017 FF	222	int timeout)
1da177e4	223	{
d6a3f017 FF	224	#ifndef MODULE
	225	int i;
	226	#endif
e525fd89	227	const fmode_t mode = FMODE_READ \| FMODE_WRITE \| FMODE_EXCL;
d6a3f017	228	struct block_device *bdev = ERR_PTR(-ENODEV);
1da177e4	229	struct block2mtd_dev *dev;
eadcf0d7	230	char *name;
1da177e4 LT	231
	232	if (!devname)
	233	return NULL;
	234
95b93a0c	235	dev = kzalloc(sizeof(struct block2mtd_dev), GFP_KERNEL);
1da177e4 LT	236	if (!dev)
1da177e4 LT	237	return NULL;
1da177e4 LT	238
1da177e4 LT	239	/* Get a handle on the device */
d4d77629	240	bdev = blkdev_get_by_path(devname, mode, dev);
c4e7fb31	241
d6a3f017 FF	242	#ifndef MODULE
	243	/*
	244	* We might not have the root device mounted at this point.
	245	* Try to resolve the device name by other means.
	246	*/
	247	for (i = 0; IS_ERR(bdev) && i <= timeout; i++) {
	248	dev_t devt;
	249
	250	if (i)
	251	/*
	252	* Calling wait_for_device_probe in the first loop
	253	* was not enough, sleep for a bit in subsequent
	254	* go-arounds.
	255	*/
	256	msleep(1000);
	257	wait_for_device_probe();
	258
	259	devt = name_to_dev_t(devname);
	260	if (!devt)
	261	continue;
	262	bdev = blkdev_get_by_dev(devt, mode, dev);
c4e7fb31 VH	263	}
	264	#endif
	265
1da177e4	266	if (IS_ERR(bdev)) {
a1c06609	267	pr_err("error: cannot open device %s\n", devname);
4bed207c	268	goto err_free_block2mtd;
1da177e4 LT	269	}
	270	dev->blkdev = bdev;
	271
	272	if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
a1c06609	273	pr_err("attempting to use an MTD device as a block device\n");
4bed207c	274	goto err_free_block2mtd;
1da177e4 LT	275	}
1da177e4 LT	276
ea6d833a FF	277	if ((long)dev->blkdev->bd_inode->i_size % erase_size) {
	278	pr_err("erasesize must be a divisor of device size\n");
	279	goto err_free_block2mtd;
	280	}
	281
48b19268	282	mutex_init(&dev->write_mutex);
1da177e4 LT	283
	284	/* Setup the MTD structure */
	285	/* make the name contain the block device in */
4d682420	286	name = kasprintf(GFP_KERNEL, "block2mtd: %s", devname);
eadcf0d7	287	if (!name)
4bed207c	288	goto err_destroy_mutex;
1da177e4	289
eadcf0d7	290	dev->mtd.name = name;
1da177e4 LT	291
	292	dev->mtd.size = dev->blkdev->bd_inode->i_size & PAGE_MASK;
	293	dev->mtd.erasesize = erase_size;
17ffc7ba	294	dev->mtd.writesize = 1;
b6043874	295	dev->mtd.writebufsize = PAGE_SIZE;
21c8db9e	296	dev->mtd.type = MTD_RAM;
1da177e4	297	dev->mtd.flags = MTD_CAP_RAM;
3c3c10bb AB	298	dev->mtd._erase = block2mtd_erase;
3c3c10bb AB	299	dev->mtd._write = block2mtd_write;
3c3c10bb AB	300	dev->mtd._sync = block2mtd_sync;
3c3c10bb AB	301	dev->mtd._read = block2mtd_read;
1da177e4 LT	302	dev->mtd.priv = dev;
	303	dev->mtd.owner = THIS_MODULE;
	304
ee0e87b1	305	if (mtd_device_register(&dev->mtd, NULL, 0)) {
25985edc	306	/* Device didn't get added, so free the entry */
4bed207c	307	goto err_destroy_mutex;
1da177e4	308	}
d6a3f017	309
1da177e4	310	list_add(&dev->list, &blkmtd_device_list);
a1c06609 JP	311	pr_info("mtd%d: [%s] erase_size = %dKiB [%d]\n",
	312	dev->mtd.index,
	313	dev->mtd.name + strlen("block2mtd: "),
	314	dev->mtd.erasesize >> 10, dev->mtd.erasesize);
1da177e4 LT	315	return dev;
1da177e4 LT	316
4bed207c FF	317	err_destroy_mutex:
	318	mutex_destroy(&dev->write_mutex);
	319	err_free_block2mtd:
1da177e4 LT	320	block2mtd_free_device(dev);
	321	return NULL;
	322	}
	323
	324
954c2422 JE	325	/* This function works similar to reguler strtoul. In addition, it
	326	* allows some suffixes for a more human-readable number format:
	327	* ki, Ki, kiB, KiB - multiply result with 1024
	328	* Mi, MiB - multiply result with 1024^2
	329	* Gi, GiB - multiply result with 1024^3
	330	*/
1da177e4 LT	331	static int ustrtoul(const char cp, char *endp, unsigned int base)
	332	{
	333	unsigned long result = simple_strtoul(cp, endp, base);
	334	switch (**endp) {
	335	case 'G' :
	336	result *= 1024;
	337	case 'M':
	338	result *= 1024;
954c2422	339	case 'K':
1da177e4 LT	340	case 'k':
	341	result *= 1024;
	342	/* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
954c2422 JE	343	if ((*endp)[1] == 'i') {
	344	if ((*endp)[2] == 'B')
	345	(*endp) += 3;
	346	else
	347	(*endp) += 2;
	348	}
1da177e4 LT	349	}
	350	return result;
	351	}
	352
	353
cc71229f	354	static int parse_num(size_t num, const char token)
1da177e4 LT	355	{
1da177e4 LT	356	char *endp;
cc71229f	357	size_t n;
1da177e4	358
cc71229f	359	n = (size_t) ustrtoul(token, &endp, 0);
1da177e4 LT	360	if (*endp)
	361	return -EINVAL;
	362
cc71229f	363	*num = n;
1da177e4 LT	364	return 0;
	365	}
	366
	367
1da177e4 LT	368	static inline void kill_final_newline(char *str)
	369	{
	370	char *newline = strrchr(str, '\n');
	371	if (newline && !newline[1])
	372	*newline = 0;
	373	}
	374
	375
c4e7fb31 VH	376	#ifndef MODULE
c4e7fb31 VH	377	static int block2mtd_init_called = 0;
d6a3f017 FF	378	/* 80 for device, 12 for erase size */
d6a3f017 FF	379	static char block2mtd_paramline[80 + 12];
c4e7fb31 VH	380	#endif
c4e7fb31 VH	381
c4e7fb31	382	static int block2mtd_setup2(const char *val)
1da177e4	383	{
d6a3f017 FF	384	/* 80 for device, 12 for erase size, 80 for name, 8 for timeout */
d6a3f017 FF	385	char buf[80 + 12 + 80 + 8];
a6550e57	386	char *str = buf;
1da177e4 LT	387	char *token[2];
1da177e4 LT	388	char *name;
cc71229f	389	size_t erase_size = PAGE_SIZE;
d6a3f017	390	unsigned long timeout = MTD_DEFAULT_TIMEOUT;
1da177e4 LT	391	int i, ret;
1da177e4 LT	392
a1c06609 JP	393	if (strnlen(val, sizeof(buf)) >= sizeof(buf)) {
	394	pr_err("parameter too long\n");
	395	return 0;
	396	}
1da177e4 LT	397
	398	strcpy(str, val);
	399	kill_final_newline(str);
	400
a6550e57	401	for (i = 0; i < 2; i++)
1da177e4 LT	402	token[i] = strsep(&str, ",");
1da177e4 LT	403
a1c06609 JP	404	if (str) {
	405	pr_err("too many arguments\n");
	406	return 0;
	407	}
1da177e4	408
a1c06609 JP	409	if (!token[0]) {
	410	pr_err("no argument\n");
	411	return 0;
	412	}
1da177e4	413
c4e7fb31	414	name = token[0];
a1c06609 JP	415	if (strlen(name) + 1 > 80) {
	416	pr_err("device name too long\n");
	417	return 0;
	418	}
1da177e4 LT	419
1da177e4 LT	420	if (token[1]) {
cc71229f	421	ret = parse_num(&erase_size, token[1]);
a6550e57	422	if (ret) {
a1c06609 JP	423	pr_err("illegal erase size\n");
a1c06609 JP	424	return 0;
a6550e57	425	}
1da177e4 LT	426	}
1da177e4 LT	427
d6a3f017	428	add_device(name, erase_size, timeout);
1da177e4 LT	429
	430	return 0;
	431	}
	432
	433
c4e7fb31 VH	434	static int block2mtd_setup(const char val, struct kernel_param kp)
	435	{
	436	#ifdef MODULE
	437	return block2mtd_setup2(val);
	438	#else
	439	/* If more parameters are later passed in via
	440	/sys/module/block2mtd/parameters/block2mtd
	441	and block2mtd_init() has already been called,
	442	we can parse the argument now. */
	443
	444	if (block2mtd_init_called)
	445	return block2mtd_setup2(val);
	446
	447	/* During early boot stage, we only save the parameters
	448	here. We must parse them later: if the param passed
	449	from kernel boot command line, block2mtd_setup() is
	450	called so early that it is not possible to resolve
	451	the device (even kmalloc() fails). Deter that work to
	452	block2mtd_setup2(). */
	453
	454	strlcpy(block2mtd_paramline, val, sizeof(block2mtd_paramline));
	455
	456	return 0;
	457	#endif
	458	}
	459
	460
1da177e4 LT	461	module_param_call(block2mtd, block2mtd_setup, NULL, NULL, 0200);
	462	MODULE_PARM_DESC(block2mtd, "Device to use. \"block2mtd=<dev>[,<erasesize>]\"");
	463
	464	static int __init block2mtd_init(void)
	465	{
c4e7fb31	466	int ret = 0;
c4e7fb31 VH	467
	468	#ifndef MODULE
	469	if (strlen(block2mtd_paramline))
	470	ret = block2mtd_setup2(block2mtd_paramline);
	471	block2mtd_init_called = 1;
	472	#endif
	473
	474	return ret;
1da177e4 LT	475	}
	476
	477
810b7e06	478	static void block2mtd_exit(void)
1da177e4 LT	479	{
	480	struct list_head pos, next;
	481
	482	/* Remove the MTD devices */
	483	list_for_each_safe(pos, next, &blkmtd_device_list) {
	484	struct block2mtd_dev dev = list_entry(pos, typeof(dev), list);
	485	block2mtd_sync(&dev->mtd);
ee0e87b1	486	mtd_device_unregister(&dev->mtd);
4bed207c	487	mutex_destroy(&dev->write_mutex);
a1c06609 JP	488	pr_info("mtd%d: [%s] removed\n",
	489	dev->mtd.index,
	490	dev->mtd.name + strlen("block2mtd: "));
1da177e4 LT	491	list_del(&dev->list);
	492	block2mtd_free_device(dev);
	493	}
	494	}
	495
d6a3f017	496	late_initcall(block2mtd_init);
1da177e4 LT	497	module_exit(block2mtd_exit);
	498
	499	MODULE_LICENSE("GPL");
2b54aaef	500	MODULE_AUTHOR("Joern Engel <joern@lazybastard.org>");
1da177e4	501	MODULE_DESCRIPTION("Emulate an MTD using a block device");