linux/drivers/mtd/mtdcore.c
Maxim Levitsky 75c0b84d41 mtd: call the remove notifiers before assuming it is in use
Now that mtd block common layer is prepared for proper hotplug support,
enable it here

Now all users of the mtd device have a chance to put the mtd device
when they are notified to do so, and they have to do so to make hotplug work.

[dwmw2: There's more work to be done to fix hotplug in the general case, but
        this is a reasonable start]

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2010-02-26 17:37:10 +00:00

688 lines
15 KiB
C

/*
* Core registration and callback routines for MTD
* drivers and users.
*
*/
#include <linux/module.h>
#include <linux/kernel.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/err.h>
#include <linux/ioctl.h>
#include <linux/init.h>
#include <linux/mtd/compatmac.h>
#include <linux/proc_fs.h>
#include <linux/idr.h>
#include <linux/mtd/mtd.h>
#include "internal.h"
#include "mtdcore.h"
static int mtd_cls_suspend(struct device *dev, pm_message_t state);
static int mtd_cls_resume(struct device *dev);
static struct class mtd_class = {
.name = "mtd",
.owner = THIS_MODULE,
.suspend = mtd_cls_suspend,
.resume = mtd_cls_resume,
};
static DEFINE_IDR(mtd_idr);
/* These are exported solely for the purpose of mtd_blkdevs.c. You
should not use them for _anything_ else */
DEFINE_MUTEX(mtd_table_mutex);
EXPORT_SYMBOL_GPL(mtd_table_mutex);
struct mtd_info *__mtd_next_device(int i)
{
return idr_get_next(&mtd_idr, &i);
}
EXPORT_SYMBOL_GPL(__mtd_next_device);
static LIST_HEAD(mtd_notifiers);
#if defined(CONFIG_MTD_CHAR) || defined(CONFIG_MTD_CHAR_MODULE)
#define MTD_DEVT(index) MKDEV(MTD_CHAR_MAJOR, (index)*2)
#else
#define MTD_DEVT(index) 0
#endif
/* REVISIT once MTD uses the driver model better, whoever allocates
* the mtd_info will probably want to use the release() hook...
*/
static void mtd_release(struct device *dev)
{
dev_t index = MTD_DEVT(dev_to_mtd(dev)->index);
/* remove /dev/mtdXro node if needed */
if (index)
device_destroy(&mtd_class, index + 1);
}
static int mtd_cls_suspend(struct device *dev, pm_message_t state)
{
struct mtd_info *mtd = dev_to_mtd(dev);
if (mtd && mtd->suspend)
return mtd->suspend(mtd);
else
return 0;
}
static int mtd_cls_resume(struct device *dev)
{
struct mtd_info *mtd = dev_to_mtd(dev);
if (mtd && mtd->resume)
mtd->resume(mtd);
return 0;
}
static ssize_t mtd_type_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct mtd_info *mtd = dev_to_mtd(dev);
char *type;
switch (mtd->type) {
case MTD_ABSENT:
type = "absent";
break;
case MTD_RAM:
type = "ram";
break;
case MTD_ROM:
type = "rom";
break;
case MTD_NORFLASH:
type = "nor";
break;
case MTD_NANDFLASH:
type = "nand";
break;
case MTD_DATAFLASH:
type = "dataflash";
break;
case MTD_UBIVOLUME:
type = "ubi";
break;
default:
type = "unknown";
}
return snprintf(buf, PAGE_SIZE, "%s\n", type);
}
static DEVICE_ATTR(type, S_IRUGO, mtd_type_show, NULL);
static ssize_t mtd_flags_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct mtd_info *mtd = dev_to_mtd(dev);
return snprintf(buf, PAGE_SIZE, "0x%lx\n", (unsigned long)mtd->flags);
}
static DEVICE_ATTR(flags, S_IRUGO, mtd_flags_show, NULL);
static ssize_t mtd_size_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct mtd_info *mtd = dev_to_mtd(dev);
return snprintf(buf, PAGE_SIZE, "%llu\n",
(unsigned long long)mtd->size);
}
static DEVICE_ATTR(size, S_IRUGO, mtd_size_show, NULL);
static ssize_t mtd_erasesize_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct mtd_info *mtd = dev_to_mtd(dev);
return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->erasesize);
}
static DEVICE_ATTR(erasesize, S_IRUGO, mtd_erasesize_show, NULL);
static ssize_t mtd_writesize_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct mtd_info *mtd = dev_to_mtd(dev);
return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->writesize);
}
static DEVICE_ATTR(writesize, S_IRUGO, mtd_writesize_show, NULL);
static ssize_t mtd_subpagesize_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct mtd_info *mtd = dev_to_mtd(dev);
unsigned int subpagesize = mtd->writesize >> mtd->subpage_sft;
return snprintf(buf, PAGE_SIZE, "%u\n", subpagesize);
}
static DEVICE_ATTR(subpagesize, S_IRUGO, mtd_subpagesize_show, NULL);
static ssize_t mtd_oobsize_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct mtd_info *mtd = dev_to_mtd(dev);
return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->oobsize);
}
static DEVICE_ATTR(oobsize, S_IRUGO, mtd_oobsize_show, NULL);
static ssize_t mtd_numeraseregions_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct mtd_info *mtd = dev_to_mtd(dev);
return snprintf(buf, PAGE_SIZE, "%u\n", mtd->numeraseregions);
}
static DEVICE_ATTR(numeraseregions, S_IRUGO, mtd_numeraseregions_show,
NULL);
static ssize_t mtd_name_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct mtd_info *mtd = dev_to_mtd(dev);
return snprintf(buf, PAGE_SIZE, "%s\n", mtd->name);
}
static DEVICE_ATTR(name, S_IRUGO, mtd_name_show, NULL);
static struct attribute *mtd_attrs[] = {
&dev_attr_type.attr,
&dev_attr_flags.attr,
&dev_attr_size.attr,
&dev_attr_erasesize.attr,
&dev_attr_writesize.attr,
&dev_attr_subpagesize.attr,
&dev_attr_oobsize.attr,
&dev_attr_numeraseregions.attr,
&dev_attr_name.attr,
NULL,
};
static struct attribute_group mtd_group = {
.attrs = mtd_attrs,
};
static const struct attribute_group *mtd_groups[] = {
&mtd_group,
NULL,
};
static struct device_type mtd_devtype = {
.name = "mtd",
.groups = mtd_groups,
.release = mtd_release,
};
/**
* 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 there is insufficient memory or a sysfs error.
*/
int add_mtd_device(struct mtd_info *mtd)
{
struct mtd_notifier *not;
int i, error;
if (!mtd->backing_dev_info) {
switch (mtd->type) {
case MTD_RAM:
mtd->backing_dev_info = &mtd_bdi_rw_mappable;
break;
case MTD_ROM:
mtd->backing_dev_info = &mtd_bdi_ro_mappable;
break;
default:
mtd->backing_dev_info = &mtd_bdi_unmappable;
break;
}
}
BUG_ON(mtd->writesize == 0);
mutex_lock(&mtd_table_mutex);
do {
if (!idr_pre_get(&mtd_idr, GFP_KERNEL))
goto fail_locked;
error = idr_get_new(&mtd_idr, mtd, &i);
} while (error == -EAGAIN);
if (error)
goto fail_locked;
mtd->index = i;
mtd->usecount = 0;
if (is_power_of_2(mtd->erasesize))
mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
else
mtd->erasesize_shift = 0;
if (is_power_of_2(mtd->writesize))
mtd->writesize_shift = ffs(mtd->writesize) - 1;
else
mtd->writesize_shift = 0;
mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;
/* Some chips always power up locked. Unlock them now */
if ((mtd->flags & MTD_WRITEABLE)
&& (mtd->flags & MTD_POWERUP_LOCK) && mtd->unlock) {
if (mtd->unlock(mtd, 0, mtd->size))
printk(KERN_WARNING
"%s: unlock failed, writes may not work\n",
mtd->name);
}
/* Caller should have set dev.parent to match the
* physical device.
*/
mtd->dev.type = &mtd_devtype;
mtd->dev.class = &mtd_class;
mtd->dev.devt = MTD_DEVT(i);
dev_set_name(&mtd->dev, "mtd%d", i);
dev_set_drvdata(&mtd->dev, mtd);
if (device_register(&mtd->dev) != 0)
goto fail_added;
if (MTD_DEVT(i))
device_create(&mtd_class, mtd->dev.parent,
MTD_DEVT(i) + 1,
NULL, "mtd%dro", i);
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_entry(not, &mtd_notifiers, 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;
fail_added:
idr_remove(&mtd_idr, i);
fail_locked:
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;
struct mtd_notifier *not;
mutex_lock(&mtd_table_mutex);
if (idr_find(&mtd_idr, mtd->index) != mtd) {
ret = -ENODEV;
goto out_error;
}
/* No need to get a refcount on the module containing
the notifier, since we hold the mtd_table_mutex */
list_for_each_entry(not, &mtd_notifiers, list)
not->remove(mtd);
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 {
device_unregister(&mtd->dev);
idr_remove(&mtd_idr, mtd->index);
module_put(THIS_MODULE);
ret = 0;
}
out_error:
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)
{
struct mtd_info *mtd;
mutex_lock(&mtd_table_mutex);
list_add(&new->list, &mtd_notifiers);
__module_get(THIS_MODULE);
mtd_for_each_device(mtd)
new->add(mtd);
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)
{
struct mtd_info *mtd;
mutex_lock(&mtd_table_mutex);
module_put(THIS_MODULE);
mtd_for_each_device(mtd)
old->remove(mtd);
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
* error code if not.
*/
struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
{
struct mtd_info *ret = NULL, *other;
int err = -ENODEV;
mutex_lock(&mtd_table_mutex);
if (num == -1) {
mtd_for_each_device(other) {
if (other == mtd) {
ret = mtd;
break;
}
}
} else if (num >= 0) {
ret = idr_find(&mtd_idr, num);
if (mtd && mtd != ret)
ret = NULL;
}
if (!ret) {
ret = ERR_PTR(err);
goto out;
}
err = __get_mtd_device(ret);
if (err)
ret = ERR_PTR(err);
out:
mutex_unlock(&mtd_table_mutex);
return ret;
}
int __get_mtd_device(struct mtd_info *mtd)
{
int err;
if (!try_module_get(mtd->owner))
return -ENODEV;
if (mtd->get_device) {
err = mtd->get_device(mtd);
if (err) {
module_put(mtd->owner);
return err;
}
}
mtd->usecount++;
return 0;
}
/**
* get_mtd_device_nm - obtain a validated handle for an MTD device by
* device name
* @name: MTD device name to open
*
* This function returns MTD device description structure in case of
* success and an error code in case of failure.
*/
struct mtd_info *get_mtd_device_nm(const char *name)
{
int err = -ENODEV;
struct mtd_info *mtd = NULL, *other;
mutex_lock(&mtd_table_mutex);
mtd_for_each_device(other) {
if (!strcmp(name, other->name)) {
mtd = other;
break;
}
}
if (!mtd)
goto out_unlock;
if (!try_module_get(mtd->owner))
goto out_unlock;
if (mtd->get_device) {
err = mtd->get_device(mtd);
if (err)
goto out_put;
}
mtd->usecount++;
mutex_unlock(&mtd_table_mutex);
return mtd;
out_put:
module_put(mtd->owner);
out_unlock:
mutex_unlock(&mtd_table_mutex);
return ERR_PTR(err);
}
void put_mtd_device(struct mtd_info *mtd)
{
mutex_lock(&mtd_table_mutex);
__put_mtd_device(mtd);
mutex_unlock(&mtd_table_mutex);
}
void __put_mtd_device(struct mtd_info *mtd)
{
--mtd->usecount;
BUG_ON(mtd->usecount < 0);
if (mtd->put_device)
mtd->put_device(mtd);
module_put(mtd->owner);
}
/* default_mtd_writev - default mtd writev method for MTD devices that
* don't 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_GPL(add_mtd_device);
EXPORT_SYMBOL_GPL(del_mtd_device);
EXPORT_SYMBOL_GPL(get_mtd_device);
EXPORT_SYMBOL_GPL(get_mtd_device_nm);
EXPORT_SYMBOL_GPL(__get_mtd_device);
EXPORT_SYMBOL_GPL(put_mtd_device);
EXPORT_SYMBOL_GPL(__put_mtd_device);
EXPORT_SYMBOL_GPL(register_mtd_user);
EXPORT_SYMBOL_GPL(unregister_mtd_user);
EXPORT_SYMBOL_GPL(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, struct mtd_info *this)
{
return sprintf(buf, "mtd%d: %8.8llx %8.8x \"%s\"\n", this->index,
(unsigned long long)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)
{
struct mtd_info *mtd;
int len, l;
off_t begin = 0;
mutex_lock(&mtd_table_mutex);
len = sprintf(page, "dev: size erasesize name\n");
mtd_for_each_device(mtd) {
l = mtd_proc_info(page + len, mtd);
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)
{
int ret;
ret = class_register(&mtd_class);
if (ret) {
pr_err("Error registering mtd class: %d\n", ret);
return ret;
}
#ifdef CONFIG_PROC_FS
if ((proc_mtd = create_proc_entry( "mtd", 0, NULL )))
proc_mtd->read_proc = mtd_read_proc;
#endif /* CONFIG_PROC_FS */
return 0;
}
static void __exit cleanup_mtd(void)
{
#ifdef CONFIG_PROC_FS
if (proc_mtd)
remove_proc_entry( "mtd", NULL);
#endif /* CONFIG_PROC_FS */
class_unregister(&mtd_class);
}
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");