[mirror_ubuntu-hirsute-kernel.git] / drivers / mtd / mtdcore.c

/*
 * $Id: mtdcore.c,v 1.47 2005/11/07 11:14:20 gleixner Exp $
 *
 * Core registration and callback routines for MTD
 * drivers and users.
 *
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/major.h>
#include <linux/fs.h>
#include <linux/ioctl.h>
#include <linux/init.h>
#include <linux/mtd/compatmac.h>
#ifdef CONFIG_PROC_FS
#include <linux/proc_fs.h>
#endif

#include <linux/mtd/mtd.h>

/* These are exported solely for the purpose of mtd_blkdevs.c. You
   should not use them for _anything_ else */
DEFINE_MUTEX(mtd_table_mutex);
struct mtd_info *mtd_table[MAX_MTD_DEVICES];

EXPORT_SYMBOL_GPL(mtd_table_mutex);
EXPORT_SYMBOL_GPL(mtd_table);

static LIST_HEAD(mtd_notifiers);

/**
 *	add_mtd_device - register an MTD device
 *	@mtd: pointer to new MTD device info structure
 *
 *	Add a device to the list of MTD devices present in the system, and
 *	notify each currently active MTD 'user' of its arrival. Returns
 *	zero on success or 1 on failure, which currently will only happen
 *	if the number of present devices exceeds MAX_MTD_DEVICES (i.e. 16)
 */

int add_mtd_device(struct mtd_info *mtd)
{
	int i;

	mutex_lock(&mtd_table_mutex);

	for (i=0; i < MAX_MTD_DEVICES; i++)
		if (!mtd_table[i]) {
			struct list_head *this;

			mtd_table[i] = mtd;
			mtd->index = i;
			mtd->usecount = 0;

			DEBUG(0, "mtd: Giving out device %d to %s\n",i, mtd->name);
			/* No need to get a refcount on the module containing
			   the notifier, since we hold the mtd_table_mutex */
			list_for_each(this, &mtd_notifiers) {
				struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list);
				not->add(mtd);
			}

			mutex_unlock(&mtd_table_mutex);
			/* We _know_ we aren't being removed, because
			   our caller is still holding us here. So none
			   of this try_ nonsense, and no bitching about it
			   either. :) */
			__module_get(THIS_MODULE);
			return 0;
		}

	mutex_unlock(&mtd_table_mutex);
	return 1;
}

/**
 *	del_mtd_device - unregister an MTD device
 *	@mtd: pointer to MTD device info structure
 *
 *	Remove a device from the list of MTD devices present in the system,
 *	and notify each currently active MTD 'user' of its departure.
 *	Returns zero on success or 1 on failure, which currently will happen
 *	if the requested device does not appear to be present in the list.
 */

int del_mtd_device (struct mtd_info *mtd)
{
	int ret;

	mutex_lock(&mtd_table_mutex);

	if (mtd_table[mtd->index] != mtd) {
		ret = -ENODEV;
	} else if (mtd->usecount) {
		printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
		       mtd->index, mtd->name, mtd->usecount);
		ret = -EBUSY;
	} else {
		struct list_head *this;

		/* No need to get a refcount on the module containing
		   the notifier, since we hold the mtd_table_mutex */
		list_for_each(this, &mtd_notifiers) {
			struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list);
			not->remove(mtd);
		}

		mtd_table[mtd->index] = NULL;

		module_put(THIS_MODULE);
		ret = 0;
	}

	mutex_unlock(&mtd_table_mutex);
	return ret;
}

/**
 *	register_mtd_user - register a 'user' of MTD devices.
 *	@new: pointer to notifier info structure
 *
 *	Registers a pair of callbacks function to be called upon addition
 *	or removal of MTD devices. Causes the 'add' callback to be immediately
 *	invoked for each MTD device currently present in the system.
 */

void register_mtd_user (struct mtd_notifier *new)
{
	int i;

	mutex_lock(&mtd_table_mutex);

	list_add(&new->list, &mtd_notifiers);

 	__module_get(THIS_MODULE);

	for (i=0; i< MAX_MTD_DEVICES; i++)
		if (mtd_table[i])
			new->add(mtd_table[i]);

	mutex_unlock(&mtd_table_mutex);
}

/**
 *	unregister_mtd_user - unregister a 'user' of MTD devices.
 *	@old: pointer to notifier info structure
 *
 *	Removes a callback function pair from the list of 'users' to be
 *	notified upon addition or removal of MTD devices. Causes the
 *	'remove' callback to be immediately invoked for each MTD device
 *	currently present in the system.
 */

int unregister_mtd_user (struct mtd_notifier *old)
{
	int i;

	mutex_lock(&mtd_table_mutex);

	module_put(THIS_MODULE);

	for (i=0; i< MAX_MTD_DEVICES; i++)
		if (mtd_table[i])
			old->remove(mtd_table[i]);

	list_del(&old->list);
	mutex_unlock(&mtd_table_mutex);
	return 0;
}


/**
 *	get_mtd_device - obtain a validated handle for an MTD device
 *	@mtd: last known address of the required MTD device
 *	@num: internal device number of the required MTD device
 *
 *	Given a number and NULL address, return the num'th entry in the device
 *	table, if any.	Given an address and num == -1, search the device table
 *	for a device with that address and return if it's still present. Given
 *	both, return the num'th driver only if its address matches. Return NULL
 *	if not.
 */

struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
{
	struct mtd_info *ret = NULL;
	int i;

	mutex_lock(&mtd_table_mutex);

	if (num == -1) {
		for (i=0; i< MAX_MTD_DEVICES; i++)
			if (mtd_table[i] == mtd)
				ret = mtd_table[i];
	} else if (num < MAX_MTD_DEVICES) {
		ret = mtd_table[num];
		if (mtd && mtd != ret)
			ret = NULL;
	}

	if (ret && !try_module_get(ret->owner))
		ret = NULL;

	if (ret)
		ret->usecount++;

	mutex_unlock(&mtd_table_mutex);
	return ret;
}

void put_mtd_device(struct mtd_info *mtd)
{
	int c;

	mutex_lock(&mtd_table_mutex);
	c = --mtd->usecount;
	mutex_unlock(&mtd_table_mutex);
	BUG_ON(c < 0);

	module_put(mtd->owner);
}

/* default_mtd_writev - default mtd writev method for MTD devices that
 *			dont implement their own
 */

int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
		       unsigned long count, loff_t to, size_t *retlen)
{
	unsigned long i;
	size_t totlen = 0, thislen;
	int ret = 0;

	if(!mtd->write) {
		ret = -EROFS;
	} else {
		for (i=0; i<count; i++) {
			if (!vecs[i].iov_len)
				continue;
			ret = mtd->write(mtd, to, vecs[i].iov_len, &thislen, vecs[i].iov_base);
			totlen += thislen;
			if (ret || thislen != vecs[i].iov_len)
				break;
			to += vecs[i].iov_len;
		}
	}
	if (retlen)
		*retlen = totlen;
	return ret;
}


/* default_mtd_readv - default mtd readv method for MTD devices that dont
 *		       implement their own
 */

int default_mtd_readv(struct mtd_info *mtd, struct kvec *vecs,
		      unsigned long count, loff_t from, size_t *retlen)
{
	unsigned long i;
	size_t totlen = 0, thislen;
	int ret = 0;

	if(!mtd->read) {
		ret = -EIO;
	} else {
		for (i=0; i<count; i++) {
			if (!vecs[i].iov_len)
				continue;
			ret = mtd->read(mtd, from, vecs[i].iov_len, &thislen, vecs[i].iov_base);
			totlen += thislen;
			if (ret || thislen != vecs[i].iov_len)
				break;
			from += vecs[i].iov_len;
		}
	}
	if (retlen)
		*retlen = totlen;
	return ret;
}


EXPORT_SYMBOL(add_mtd_device);
EXPORT_SYMBOL(del_mtd_device);
EXPORT_SYMBOL(get_mtd_device);
EXPORT_SYMBOL(put_mtd_device);
EXPORT_SYMBOL(register_mtd_user);
EXPORT_SYMBOL(unregister_mtd_user);
EXPORT_SYMBOL(default_mtd_writev);
EXPORT_SYMBOL(default_mtd_readv);

/*====================================================================*/
/* Support for /proc/mtd */

#ifdef CONFIG_PROC_FS
static struct proc_dir_entry *proc_mtd;

static inline int mtd_proc_info (char *buf, int i)
{
	struct mtd_info *this = mtd_table[i];

	if (!this)
		return 0;

	return sprintf(buf, "mtd%d: %8.8x %8.8x \"%s\"\n", i, this->size,
		       this->erasesize, this->name);
}

static int mtd_read_proc (char *page, char **start, off_t off, int count,
			  int *eof, void *data_unused)
{
	int len, l, i;
        off_t   begin = 0;

	mutex_lock(&mtd_table_mutex);

	len = sprintf(page, "dev:    size   erasesize  name\n");
        for (i=0; i< MAX_MTD_DEVICES; i++) {

                l = mtd_proc_info(page + len, i);
                len += l;
                if (len+begin > off+count)
                        goto done;
                if (len+begin < off) {
                        begin += len;
                        len = 0;
                }
        }

        *eof = 1;

done:
	mutex_unlock(&mtd_table_mutex);
        if (off >= len+begin)
                return 0;
        *start = page + (off-begin);
        return ((count < begin+len-off) ? count : begin+len-off);
}

#endif /* CONFIG_PROC_FS */

/*====================================================================*/
/* Init code */

static int __init init_mtd(void)
{
#ifdef CONFIG_PROC_FS
	if ((proc_mtd = create_proc_entry( "mtd", 0, NULL )))
		proc_mtd->read_proc = mtd_read_proc;
#endif
	return 0;
}

static void __exit cleanup_mtd(void)
{
#ifdef CONFIG_PROC_FS
        if (proc_mtd)
		remove_proc_entry( "mtd", NULL);
#endif
}

module_init(init_mtd);
module_exit(cleanup_mtd);


MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
MODULE_DESCRIPTION("Core MTD registration and access routines");
Commit	Line	Data
1da177e4	1	/*
97894cda	2	* $Id: mtdcore.c,v 1.47 2005/11/07 11:14:20 gleixner Exp $
1da177e4 LT	3	*
	4	* Core registration and callback routines for MTD
	5	* drivers and users.
	6	*
	7	*/
	8
	9	#include <linux/config.h>
	10	#include <linux/module.h>
	11	#include <linux/kernel.h>
	12	#include <linux/sched.h>
	13	#include <linux/ptrace.h>
	14	#include <linux/slab.h>
	15	#include <linux/string.h>
	16	#include <linux/timer.h>
	17	#include <linux/major.h>
	18	#include <linux/fs.h>
	19	#include <linux/ioctl.h>
	20	#include <linux/init.h>
	21	#include <linux/mtd/compatmac.h>
	22	#ifdef CONFIG_PROC_FS
	23	#include <linux/proc_fs.h>
	24	#endif
	25
	26	#include <linux/mtd/mtd.h>
	27
97894cda	28	/* These are exported solely for the purpose of mtd_blkdevs.c. You
1da177e4	29	should not use them for _anything_ else */
48b19268	30	DEFINE_MUTEX(mtd_table_mutex);
1da177e4 LT	31	struct mtd_info *mtd_table[MAX_MTD_DEVICES];
	32
	33	EXPORT_SYMBOL_GPL(mtd_table_mutex);
	34	EXPORT_SYMBOL_GPL(mtd_table);
	35
	36	static LIST_HEAD(mtd_notifiers);
	37
	38	/**
	39	* add_mtd_device - register an MTD device
	40	* @mtd: pointer to new MTD device info structure
	41	*
	42	* Add a device to the list of MTD devices present in the system, and
	43	* notify each currently active MTD 'user' of its arrival. Returns
	44	* zero on success or 1 on failure, which currently will only happen
	45	* if the number of present devices exceeds MAX_MTD_DEVICES (i.e. 16)
	46	*/
	47
	48	int add_mtd_device(struct mtd_info *mtd)
	49	{
	50	int i;
	51
48b19268	52	mutex_lock(&mtd_table_mutex);
1da177e4 LT	53
	54	for (i=0; i < MAX_MTD_DEVICES; i++)
	55	if (!mtd_table[i]) {
	56	struct list_head *this;
	57
	58	mtd_table[i] = mtd;
	59	mtd->index = i;
	60	mtd->usecount = 0;
	61
	62	DEBUG(0, "mtd: Giving out device %d to %s\n",i, mtd->name);
	63	/* No need to get a refcount on the module containing
	64	the notifier, since we hold the mtd_table_mutex */
	65	list_for_each(this, &mtd_notifiers) {
	66	struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list);
	67	not->add(mtd);
	68	}
97894cda	69
48b19268	70	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	71	/* We _know_ we aren't being removed, because
	72	our caller is still holding us here. So none
	73	of this try_ nonsense, and no bitching about it
	74	either. :) */
	75	__module_get(THIS_MODULE);
	76	return 0;
	77	}
97894cda	78
48b19268	79	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	80	return 1;
	81	}
	82
	83	/**
	84	* del_mtd_device - unregister an MTD device
	85	* @mtd: pointer to MTD device info structure
	86	*
	87	* Remove a device from the list of MTD devices present in the system,
	88	* and notify each currently active MTD 'user' of its departure.
	89	* Returns zero on success or 1 on failure, which currently will happen
	90	* if the requested device does not appear to be present in the list.
	91	*/
	92
	93	int del_mtd_device (struct mtd_info *mtd)
	94	{
	95	int ret;
97894cda	96
48b19268	97	mutex_lock(&mtd_table_mutex);
1da177e4 LT	98
	99	if (mtd_table[mtd->index] != mtd) {
	100	ret = -ENODEV;
	101	} else if (mtd->usecount) {
97894cda	102	printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
1da177e4 LT	103	mtd->index, mtd->name, mtd->usecount);
	104	ret = -EBUSY;
	105	} else {
	106	struct list_head *this;
	107
	108	/* No need to get a refcount on the module containing
	109	the notifier, since we hold the mtd_table_mutex */
	110	list_for_each(this, &mtd_notifiers) {
	111	struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list);
	112	not->remove(mtd);
	113	}
	114
	115	mtd_table[mtd->index] = NULL;
	116
	117	module_put(THIS_MODULE);
	118	ret = 0;
	119	}
	120
48b19268	121	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	122	return ret;
	123	}
	124
	125	/**
	126	* register_mtd_user - register a 'user' of MTD devices.
	127	* @new: pointer to notifier info structure
	128	*
	129	* Registers a pair of callbacks function to be called upon addition
	130	* or removal of MTD devices. Causes the 'add' callback to be immediately
	131	* invoked for each MTD device currently present in the system.
	132	*/
	133
	134	void register_mtd_user (struct mtd_notifier *new)
	135	{
	136	int i;
	137
48b19268	138	mutex_lock(&mtd_table_mutex);
1da177e4 LT	139
	140	list_add(&new->list, &mtd_notifiers);
	141
	142	__module_get(THIS_MODULE);
97894cda	143
1da177e4 LT	144	for (i=0; i< MAX_MTD_DEVICES; i++)
	145	if (mtd_table[i])
	146	new->add(mtd_table[i]);
	147
48b19268	148	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	149	}
	150
	151	/**
49450795 AB	152	* unregister_mtd_user - unregister a 'user' of MTD devices.
49450795 AB	153	* @old: pointer to notifier info structure
1da177e4 LT	154	*
	155	* Removes a callback function pair from the list of 'users' to be
	156	* notified upon addition or removal of MTD devices. Causes the
	157	* 'remove' callback to be immediately invoked for each MTD device
	158	* currently present in the system.
	159	*/
	160
	161	int unregister_mtd_user (struct mtd_notifier *old)
	162	{
	163	int i;
	164
48b19268	165	mutex_lock(&mtd_table_mutex);
1da177e4 LT	166
	167	module_put(THIS_MODULE);
	168
	169	for (i=0; i< MAX_MTD_DEVICES; i++)
	170	if (mtd_table[i])
	171	old->remove(mtd_table[i]);
97894cda	172
1da177e4	173	list_del(&old->list);
48b19268	174	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	175	return 0;
	176	}
	177
	178
	179	/**
	180	* get_mtd_device - obtain a validated handle for an MTD device
	181	* @mtd: last known address of the required MTD device
	182	* @num: internal device number of the required MTD device
	183	*
	184	* Given a number and NULL address, return the num'th entry in the device
	185	* table, if any. Given an address and num == -1, search the device table
	186	* for a device with that address and return if it's still present. Given
	187	* both, return the num'th driver only if its address matches. Return NULL
	188	* if not.
	189	*/
97894cda	190
1da177e4 LT	191	struct mtd_info get_mtd_device(struct mtd_info mtd, int num)
	192	{
	193	struct mtd_info *ret = NULL;
	194	int i;
	195
48b19268	196	mutex_lock(&mtd_table_mutex);
1da177e4 LT	197
	198	if (num == -1) {
	199	for (i=0; i< MAX_MTD_DEVICES; i++)
	200	if (mtd_table[i] == mtd)
	201	ret = mtd_table[i];
	202	} else if (num < MAX_MTD_DEVICES) {
	203	ret = mtd_table[num];
	204	if (mtd && mtd != ret)
	205	ret = NULL;
	206	}
	207
	208	if (ret && !try_module_get(ret->owner))
	209	ret = NULL;
	210
	211	if (ret)
	212	ret->usecount++;
	213
48b19268	214	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	215	return ret;
	216	}
	217
	218	void put_mtd_device(struct mtd_info *mtd)
	219	{
	220	int c;
	221
48b19268	222	mutex_lock(&mtd_table_mutex);
1da177e4	223	c = --mtd->usecount;
48b19268	224	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	225	BUG_ON(c < 0);
	226
	227	module_put(mtd->owner);
	228	}
	229
	230	/* default_mtd_writev - default mtd writev method for MTD devices that
	231	* dont implement their own
	232	*/
	233
	234	int default_mtd_writev(struct mtd_info mtd, const struct kvec vecs,
	235	unsigned long count, loff_t to, size_t *retlen)
	236	{
	237	unsigned long i;
	238	size_t totlen = 0, thislen;
	239	int ret = 0;
	240
	241	if(!mtd->write) {
	242	ret = -EROFS;
	243	} else {
	244	for (i=0; i<count; i++) {
	245	if (!vecs[i].iov_len)
	246	continue;
	247	ret = mtd->write(mtd, to, vecs[i].iov_len, &thislen, vecs[i].iov_base);
	248	totlen += thislen;
	249	if (ret \|\| thislen != vecs[i].iov_len)
	250	break;
	251	to += vecs[i].iov_len;
	252	}
	253	}
	254	if (retlen)
	255	*retlen = totlen;
	256	return ret;
	257	}
	258
	259
	260	/* default_mtd_readv - default mtd readv method for MTD devices that dont
	261	* implement their own
	262	*/
	263
	264	int default_mtd_readv(struct mtd_info mtd, struct kvec vecs,
	265	unsigned long count, loff_t from, size_t *retlen)
	266	{
	267	unsigned long i;
	268	size_t totlen = 0, thislen;
	269	int ret = 0;
	270
	271	if(!mtd->read) {
	272	ret = -EIO;
	273	} else {
	274	for (i=0; i<count; i++) {
	275	if (!vecs[i].iov_len)
	276	continue;
	277	ret = mtd->read(mtd, from, vecs[i].iov_len, &thislen, vecs[i].iov_base);
	278	totlen += thislen;
	279	if (ret \|\| thislen != vecs[i].iov_len)
	280	break;
	281	from += vecs[i].iov_len;
	282	}
	283	}
	284	if (retlen)
	285	*retlen = totlen;
	286	return ret;
	287	}
	288
289
290	EXPORT_SYMBOL(add_mtd_device);
291	EXPORT_SYMBOL(del_mtd_device);
292	EXPORT_SYMBOL(get_mtd_device);
293	EXPORT_SYMBOL(put_mtd_device);
294	EXPORT_SYMBOL(register_mtd_user);
295	EXPORT_SYMBOL(unregister_mtd_user);
296	EXPORT_SYMBOL(default_mtd_writev);
297	EXPORT_SYMBOL(default_mtd_readv);
298
1da177e4 LT	299	/====================================================================/
	300	/* Support for /proc/mtd */
	301
	302	#ifdef CONFIG_PROC_FS
	303	static struct proc_dir_entry *proc_mtd;
	304
	305	static inline int mtd_proc_info (char *buf, int i)
	306	{
	307	struct mtd_info *this = mtd_table[i];
	308
	309	if (!this)
	310	return 0;
	311
	312	return sprintf(buf, "mtd%d: %8.8x %8.8x \"%s\"\n", i, this->size,
	313	this->erasesize, this->name);
	314	}
	315
	316	static int mtd_read_proc (char page, char *start, off_t off, int count,
	317	int eof, void data_unused)
	318	{
	319	int len, l, i;
	320	off_t begin = 0;
	321
48b19268	322	mutex_lock(&mtd_table_mutex);
1da177e4 LT	323
	324	len = sprintf(page, "dev: size erasesize name\n");
	325	for (i=0; i< MAX_MTD_DEVICES; i++) {
	326
	327	l = mtd_proc_info(page + len, i);
	328	len += l;
	329	if (len+begin > off+count)
	330	goto done;
	331	if (len+begin < off) {
	332	begin += len;
	333	len = 0;
	334	}
	335	}
	336
	337	*eof = 1;
	338
	339	done:
48b19268	340	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	341	if (off >= len+begin)
	342	return 0;
	343	*start = page + (off-begin);
	344	return ((count < begin+len-off) ? count : begin+len-off);
	345	}
	346
	347	#endif /* CONFIG_PROC_FS */
	348
	349	/====================================================================/
	350	/* Init code */
	351
	352	static int __init init_mtd(void)
	353	{
	354	#ifdef CONFIG_PROC_FS
	355	if ((proc_mtd = create_proc_entry( "mtd", 0, NULL )))
	356	proc_mtd->read_proc = mtd_read_proc;
	357	#endif
1da177e4 LT	358	return 0;
	359	}
	360
	361	static void __exit cleanup_mtd(void)
	362	{
1da177e4 LT	363	#ifdef CONFIG_PROC_FS
	364	if (proc_mtd)
	365	remove_proc_entry( "mtd", NULL);
	366	#endif
	367	}
	368
	369	module_init(init_mtd);
	370	module_exit(cleanup_mtd);
	371
	372
	373	MODULE_LICENSE("GPL");
	374	MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
	375	MODULE_DESCRIPTION("Core MTD registration and access routines");