drivers/mtd/mtdcore.c - kernel/msm-4.19 - Gitiles

 /*
  * $Id: mtdcore.c,v 1.46 2005/08/11 17:13:43 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 */
 DECLARE_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;

 	down(&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);
 			}

 			up(&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;
 		}

 	up(&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;

 	down(&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;
 	}

 	up(&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;

 	down(&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]);

 	up(&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;

 	down(&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);
 	up(&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;

 	down(&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++;

 	up(&mtd_table_mutex);
 	return ret;
 }

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

 	down(&mtd_table_mutex);
 	c = --mtd->usecount;
 	up(&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;

 	down(&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:
 	up(&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");
	/*
	* $Id: mtdcore.c,v 1.46 2005/08/11 17:13:43 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 */
	DECLARE_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;

	down(&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);
	}

	up(&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;
	}

	up(&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;

	down(&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;
	}

	up(&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;

	down(&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]);

	up(&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;

	down(&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);
	up(&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;

	down(&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++;

	up(&mtd_table_mutex);
	return ret;
	}

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

	down(&mtd_table_mutex);
	c = --mtd->usecount;
	up(&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;

	down(&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:
	up(&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");