/*
* $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/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>
#include <linux/proc_fs.h>
#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;
BUG_ON(mtd->writesize == 0);
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;
}
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);
#ifdef CONFIG_PROC_FS
/*====================================================================*/
/* Support for /proc/mtd */
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);
}
/*====================================================================*/
/* Init code */
static int __init init_mtd(void)
{
if ((proc_mtd = create_proc_entry( "mtd", 0, NULL )))
proc_mtd->read_proc = mtd_read_proc;
return 0;
}
static void __exit cleanup_mtd(void)
{
if (proc_mtd)
remove_proc_entry( "mtd", NULL);
}
module_init(init_mtd);
module_exit(cleanup_mtd);
#endif /* CONFIG_PROC_FS */
MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
MODULE_DESCRIPTION("Core MTD registration and access routines");
