- 根目录:
- drivers
- mtd
- mtdcore.c
/*
* Core registration and callback routines for MTD
* drivers and users.
*
* Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
* Copyright © 2006 Red Hat UK Limited
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/ptrace.h>
#include <linux/seq_file.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/proc_fs.h>
#include <linux/idr.h>
#include <linux/backing-dev.h>
#include <linux/gfp.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include "mtdcore.h"
/*
* backing device capabilities for non-mappable devices (such as NAND flash)
* - permits private mappings, copies are taken of the data
*/
static struct backing_dev_info mtd_bdi_unmappable = {
.capabilities = BDI_CAP_MAP_COPY,
};
/*
* backing device capabilities for R/O mappable devices (such as ROM)
* - permits private mappings, copies are taken of the data
* - permits non-writable shared mappings
*/
static struct backing_dev_info mtd_bdi_ro_mappable = {
.capabilities = (BDI_CAP_MAP_COPY | BDI_CAP_MAP_DIRECT |
BDI_CAP_EXEC_MAP | BDI_CAP_READ_MAP),
};
/*
* backing device capabilities for writable mappable devices (such as RAM)
* - permits private mappings, copies are taken of the data
* - permits non-writable shared mappings
*/
static struct backing_dev_info mtd_bdi_rw_mappable = {
.capabilities = (BDI_CAP_MAP_COPY | BDI_CAP_MAP_DIRECT |
BDI_CAP_EXEC_MAP | BDI_CAP_READ_MAP |
BDI_CAP_WRITE_MAP),
};
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;
}
/**
* mtd_device_register - register an MTD device.
*
* @master: the MTD device to register
* @parts: the partitions to register - only valid if nr_parts > 0
* @nr_parts: the number of partitions in parts. If zero then the full MTD
* device is registered
*
* Register an MTD device with the system and optionally, a number of
* partitions. If nr_parts is 0 then the whole device is registered, otherwise
* only the partitions are registered. To register both the full device *and*
* the partitions, call mtd_device_register() twice, once with nr_parts == 0
* and once equal to the number of partitions.
*/
int mtd_device_register(struct mtd_info *master,
const struct mtd_partition *parts,
int nr_parts)
{
return parts ? add_mtd_partitions(master, parts, nr_parts) :
add_mtd_device(master);
}
EXPORT_SYMBOL_GPL(mtd_device_register);
/**
* mtd_device_unregister - unregister an existing MTD device.
*
* @master: the MTD device to unregister. This will unregister both the master
* and any partitions if registered.
*/
int mtd_device_unregister(struct mtd_info *master)
{
int err;
err = del_mtd_partitions(master);
if (err)
return err;
if (!device_is_registered(&master->dev))
return 0;
return del_mtd_device(master);
}
EXPORT_SYMBOL_GPL(mtd_device_unregister);
/**
* 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;
err = __get_mtd_device(mtd);
if (err)
goto out_unlock;
mutex_unlock(&mtd_table_mutex);
return mtd;
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;
}
/**
* mtd_kmalloc_up_to - allocate a contiguous buffer up to the specified size
* @size: A pointer to the ideal or maximum size of the allocation. Points
* to the actual allocation size on success.
*
* This routine attempts to allocate a contiguous kernel buffer up to
* the specified size, backing off the size of the request exponentially
* until the request succeeds or until the allocation size falls below
* the system page size. This attempts to make sure it does not adversely
* impact system performance, so when allocating more than one page, we
* ask the memory allocator to avoid re-trying, swapping, writing back
* or performing I/O.
*
* Note, this function also makes sure that the allocated buffer is aligned to
* the MTD device's min. I/O unit, i.e. the "mtd->writesize" value.
*
* This is called, for example by mtd_{read,write} and jffs2_scan_medium,
* to handle smaller (i.e. degraded) buffer allocations under low- or
* fragmented-memory situations where such reduced allocations, from a
* requested ideal, are allowed.
*
* Returns a pointer to the allocated buffer on success; otherwise, NULL.
*/
void *mtd_kmalloc_up_to(const struct mtd_info *mtd, size_t *size)
{
gfp_t flags = __GFP_NOWARN | __GFP_WAIT |
__GFP_NORETRY | __GFP_NO_KSWAPD;
size_t min_alloc = max_t(size_t, mtd->writesize, PAGE_SIZE);
void *kbuf;
*size = min_t(size_t, *size, KMALLOC_MAX_SIZE);
while (*size > min_alloc) {
kbuf = kmalloc(*size, flags);
if (kbuf)
return kbuf;
*size >>= 1;
*size = ALIGN(*size, mtd->writesize);
}
/*
* For the last resort allocation allow 'kmalloc()' to do all sorts of
* things (write-back, dropping caches, etc) by using GFP_KERNEL.
*/
return kmalloc(*size, GFP_KERNEL);
}
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);
EXPORT_SYMBOL_GPL(mtd_kmalloc_up_to);
#ifdef CONFIG_PROC_FS
/*====================================================================*/
/* Support for /proc/mtd */
static struct proc_dir_entry *proc_mtd;
static int mtd_proc_show(struct seq_file *m, void *v)
{
struct mtd_info *mtd;
seq_puts(m, "dev: size erasesize name\n");
mutex_lock(&mtd_table_mutex);
mtd_for_each_device(mtd) {
seq_printf(m, "mtd%d: %8.8llx %8.8x \"%s\"\n",
mtd->index, (unsigned long long)mtd->size,
mtd->erasesize, mtd->name);
}
mutex_unlock(&mtd_table_mutex);
return 0;
}
static int mtd_proc_open(struct inode *inode, struct file *file)
{
return single_open(file, mtd_proc_show, NULL);
}
static const struct file_operations mtd_proc_ops = {
.open = mtd_proc_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
#endif /* CONFIG_PROC_FS */
/*====================================================================*/
/* Init code */
static int __init mtd_bdi_init(struct backing_dev_info *bdi, const char *name)
{
int ret;
ret = bdi_init(bdi);
if (!ret)
ret = bdi_register(bdi, NULL, name);
if (ret)
bdi_destroy(bdi);
return ret;
}
static int __init init_mtd(void)
{
int ret;
ret = class_register(&mtd_class);
if (ret)
goto err_reg;
ret = mtd_bdi_init(&mtd_bdi_unmappable, "mtd-unmap");
if (ret)
goto err_bdi1;
ret = mtd_bdi_init(&mtd_bdi_ro_mappable, "mtd-romap");
if (ret)
goto err_bdi2;
ret = mtd_bdi_init(&mtd_bdi_rw_mappable, "mtd-rwmap");
if (ret)
goto err_bdi3;
#ifdef CONFIG_PROC_FS
proc_mtd = proc_create("mtd", 0, NULL, &mtd_proc_ops);
#endif /* CONFIG_PROC_FS */
return 0;
err_bdi3:
bdi_destroy(&mtd_bdi_ro_mappable);
err_bdi2:
bdi_destroy(&mtd_bdi_unmappable);
err_bdi1:
class_unregister(&mtd_class);
err_reg:
pr_err("Error registering mtd class or bdi: %d\n", ret);
return ret;
}
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);
bdi_destroy(&mtd_bdi_unmappable);
bdi_destroy(&mtd_bdi_ro_mappable);
bdi_destroy(&mtd_bdi_rw_mappable);
}
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");