/* * $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 */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_FSstatic 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");