494 строки
10 KiB
C
494 строки
10 KiB
C
/*
|
|
* $Id: block2mtd.c,v 1.28 2005/03/19 22:40:44 gleixner Exp $
|
|
*
|
|
* block2mtd.c - create an mtd from a block device
|
|
*
|
|
* Copyright (C) 2001,2002 Simon Evans <spse@secret.org.uk>
|
|
* Copyright (C) 2004,2005 Jörn Engel <joern@wh.fh-wedel.de>
|
|
*
|
|
* Licence: GPL
|
|
*/
|
|
#include <linux/config.h>
|
|
#include <linux/module.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/bio.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/list.h>
|
|
#include <linux/init.h>
|
|
#include <linux/mtd/mtd.h>
|
|
#include <linux/buffer_head.h>
|
|
|
|
#define VERSION "$Revision: 1.28 $"
|
|
|
|
|
|
#define ERROR(fmt, args...) printk(KERN_ERR "block2mtd: " fmt "\n" , ## args)
|
|
#define INFO(fmt, args...) printk(KERN_INFO "block2mtd: " fmt "\n" , ## args)
|
|
|
|
|
|
/* Info for the block device */
|
|
struct block2mtd_dev {
|
|
struct list_head list;
|
|
struct block_device *blkdev;
|
|
struct mtd_info mtd;
|
|
struct semaphore write_mutex;
|
|
};
|
|
|
|
|
|
/* Static info about the MTD, used in cleanup_module */
|
|
static LIST_HEAD(blkmtd_device_list);
|
|
|
|
|
|
#define PAGE_READAHEAD 64
|
|
void cache_readahead(struct address_space *mapping, int index)
|
|
{
|
|
filler_t *filler = (filler_t*)mapping->a_ops->readpage;
|
|
int i, pagei;
|
|
unsigned ret = 0;
|
|
unsigned long end_index;
|
|
struct page *page;
|
|
LIST_HEAD(page_pool);
|
|
struct inode *inode = mapping->host;
|
|
loff_t isize = i_size_read(inode);
|
|
|
|
if (!isize) {
|
|
INFO("iSize=0 in cache_readahead\n");
|
|
return;
|
|
}
|
|
|
|
end_index = ((isize - 1) >> PAGE_CACHE_SHIFT);
|
|
|
|
read_lock_irq(&mapping->tree_lock);
|
|
for (i = 0; i < PAGE_READAHEAD; i++) {
|
|
pagei = index + i;
|
|
if (pagei > end_index) {
|
|
INFO("Overrun end of disk in cache readahead\n");
|
|
break;
|
|
}
|
|
page = radix_tree_lookup(&mapping->page_tree, pagei);
|
|
if (page && (!i))
|
|
break;
|
|
if (page)
|
|
continue;
|
|
read_unlock_irq(&mapping->tree_lock);
|
|
page = page_cache_alloc_cold(mapping);
|
|
read_lock_irq(&mapping->tree_lock);
|
|
if (!page)
|
|
break;
|
|
page->index = pagei;
|
|
list_add(&page->lru, &page_pool);
|
|
ret++;
|
|
}
|
|
read_unlock_irq(&mapping->tree_lock);
|
|
if (ret)
|
|
read_cache_pages(mapping, &page_pool, filler, NULL);
|
|
}
|
|
|
|
|
|
static struct page* page_readahead(struct address_space *mapping, int index)
|
|
{
|
|
filler_t *filler = (filler_t*)mapping->a_ops->readpage;
|
|
cache_readahead(mapping, index);
|
|
return read_cache_page(mapping, index, filler, NULL);
|
|
}
|
|
|
|
|
|
/* erase a specified part of the device */
|
|
static int _block2mtd_erase(struct block2mtd_dev *dev, loff_t to, size_t len)
|
|
{
|
|
struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;
|
|
struct page *page;
|
|
int index = to >> PAGE_SHIFT; // page index
|
|
int pages = len >> PAGE_SHIFT;
|
|
u_long *p;
|
|
u_long *max;
|
|
|
|
while (pages) {
|
|
page = page_readahead(mapping, index);
|
|
if (!page)
|
|
return -ENOMEM;
|
|
if (IS_ERR(page))
|
|
return PTR_ERR(page);
|
|
|
|
max = (u_long*)page_address(page) + PAGE_SIZE;
|
|
for (p=(u_long*)page_address(page); p<max; p++)
|
|
if (*p != -1UL) {
|
|
lock_page(page);
|
|
memset(page_address(page), 0xff, PAGE_SIZE);
|
|
set_page_dirty(page);
|
|
unlock_page(page);
|
|
break;
|
|
}
|
|
|
|
page_cache_release(page);
|
|
pages--;
|
|
index++;
|
|
}
|
|
return 0;
|
|
}
|
|
static int block2mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
|
|
{
|
|
struct block2mtd_dev *dev = mtd->priv;
|
|
size_t from = instr->addr;
|
|
size_t len = instr->len;
|
|
int err;
|
|
|
|
instr->state = MTD_ERASING;
|
|
down(&dev->write_mutex);
|
|
err = _block2mtd_erase(dev, from, len);
|
|
up(&dev->write_mutex);
|
|
if (err) {
|
|
ERROR("erase failed err = %d", err);
|
|
instr->state = MTD_ERASE_FAILED;
|
|
} else
|
|
instr->state = MTD_ERASE_DONE;
|
|
|
|
instr->state = MTD_ERASE_DONE;
|
|
mtd_erase_callback(instr);
|
|
return err;
|
|
}
|
|
|
|
|
|
static int block2mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
|
|
size_t *retlen, u_char *buf)
|
|
{
|
|
struct block2mtd_dev *dev = mtd->priv;
|
|
struct page *page;
|
|
int index = from >> PAGE_SHIFT;
|
|
int offset = from & (PAGE_SIZE-1);
|
|
int cpylen;
|
|
|
|
if (from > mtd->size)
|
|
return -EINVAL;
|
|
if (from + len > mtd->size)
|
|
len = mtd->size - from;
|
|
|
|
if (retlen)
|
|
*retlen = 0;
|
|
|
|
while (len) {
|
|
if ((offset + len) > PAGE_SIZE)
|
|
cpylen = PAGE_SIZE - offset; // multiple pages
|
|
else
|
|
cpylen = len; // this page
|
|
len = len - cpylen;
|
|
|
|
// Get page
|
|
page = page_readahead(dev->blkdev->bd_inode->i_mapping, index);
|
|
if (!page)
|
|
return -ENOMEM;
|
|
if (IS_ERR(page))
|
|
return PTR_ERR(page);
|
|
|
|
memcpy(buf, page_address(page) + offset, cpylen);
|
|
page_cache_release(page);
|
|
|
|
if (retlen)
|
|
*retlen += cpylen;
|
|
buf += cpylen;
|
|
offset = 0;
|
|
index++;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
/* write data to the underlying device */
|
|
static int _block2mtd_write(struct block2mtd_dev *dev, const u_char *buf,
|
|
loff_t to, size_t len, size_t *retlen)
|
|
{
|
|
struct page *page;
|
|
struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;
|
|
int index = to >> PAGE_SHIFT; // page index
|
|
int offset = to & ~PAGE_MASK; // page offset
|
|
int cpylen;
|
|
|
|
if (retlen)
|
|
*retlen = 0;
|
|
while (len) {
|
|
if ((offset+len) > PAGE_SIZE)
|
|
cpylen = PAGE_SIZE - offset; // multiple pages
|
|
else
|
|
cpylen = len; // this page
|
|
len = len - cpylen;
|
|
|
|
// Get page
|
|
page = page_readahead(mapping, index);
|
|
if (!page)
|
|
return -ENOMEM;
|
|
if (IS_ERR(page))
|
|
return PTR_ERR(page);
|
|
|
|
if (memcmp(page_address(page)+offset, buf, cpylen)) {
|
|
lock_page(page);
|
|
memcpy(page_address(page) + offset, buf, cpylen);
|
|
set_page_dirty(page);
|
|
unlock_page(page);
|
|
}
|
|
page_cache_release(page);
|
|
|
|
if (retlen)
|
|
*retlen += cpylen;
|
|
|
|
buf += cpylen;
|
|
offset = 0;
|
|
index++;
|
|
}
|
|
return 0;
|
|
}
|
|
static int block2mtd_write(struct mtd_info *mtd, loff_t to, size_t len,
|
|
size_t *retlen, const u_char *buf)
|
|
{
|
|
struct block2mtd_dev *dev = mtd->priv;
|
|
int err;
|
|
|
|
if (!len)
|
|
return 0;
|
|
if (to >= mtd->size)
|
|
return -ENOSPC;
|
|
if (to + len > mtd->size)
|
|
len = mtd->size - to;
|
|
|
|
down(&dev->write_mutex);
|
|
err = _block2mtd_write(dev, buf, to, len, retlen);
|
|
up(&dev->write_mutex);
|
|
if (err > 0)
|
|
err = 0;
|
|
return err;
|
|
}
|
|
|
|
|
|
/* sync the device - wait until the write queue is empty */
|
|
static void block2mtd_sync(struct mtd_info *mtd)
|
|
{
|
|
struct block2mtd_dev *dev = mtd->priv;
|
|
sync_blockdev(dev->blkdev);
|
|
return;
|
|
}
|
|
|
|
|
|
static void block2mtd_free_device(struct block2mtd_dev *dev)
|
|
{
|
|
if (!dev)
|
|
return;
|
|
|
|
kfree(dev->mtd.name);
|
|
|
|
if (dev->blkdev) {
|
|
invalidate_inode_pages(dev->blkdev->bd_inode->i_mapping);
|
|
close_bdev_excl(dev->blkdev);
|
|
}
|
|
|
|
kfree(dev);
|
|
}
|
|
|
|
|
|
/* FIXME: ensure that mtd->size % erase_size == 0 */
|
|
static struct block2mtd_dev *add_device(char *devname, int erase_size)
|
|
{
|
|
struct block_device *bdev;
|
|
struct block2mtd_dev *dev;
|
|
|
|
if (!devname)
|
|
return NULL;
|
|
|
|
dev = kmalloc(sizeof(struct block2mtd_dev), GFP_KERNEL);
|
|
if (!dev)
|
|
return NULL;
|
|
memset(dev, 0, sizeof(*dev));
|
|
|
|
/* Get a handle on the device */
|
|
bdev = open_bdev_excl(devname, O_RDWR, NULL);
|
|
if (IS_ERR(bdev)) {
|
|
ERROR("error: cannot open device %s", devname);
|
|
goto devinit_err;
|
|
}
|
|
dev->blkdev = bdev;
|
|
|
|
if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
|
|
ERROR("attempting to use an MTD device as a block device");
|
|
goto devinit_err;
|
|
}
|
|
|
|
init_MUTEX(&dev->write_mutex);
|
|
|
|
/* Setup the MTD structure */
|
|
/* make the name contain the block device in */
|
|
dev->mtd.name = kmalloc(sizeof("block2mtd: ") + strlen(devname),
|
|
GFP_KERNEL);
|
|
if (!dev->mtd.name)
|
|
goto devinit_err;
|
|
|
|
sprintf(dev->mtd.name, "block2mtd: %s", devname);
|
|
|
|
dev->mtd.size = dev->blkdev->bd_inode->i_size & PAGE_MASK;
|
|
dev->mtd.erasesize = erase_size;
|
|
dev->mtd.type = MTD_RAM;
|
|
dev->mtd.flags = MTD_CAP_RAM;
|
|
dev->mtd.erase = block2mtd_erase;
|
|
dev->mtd.write = block2mtd_write;
|
|
dev->mtd.writev = default_mtd_writev;
|
|
dev->mtd.sync = block2mtd_sync;
|
|
dev->mtd.read = block2mtd_read;
|
|
dev->mtd.readv = default_mtd_readv;
|
|
dev->mtd.priv = dev;
|
|
dev->mtd.owner = THIS_MODULE;
|
|
|
|
if (add_mtd_device(&dev->mtd)) {
|
|
/* Device didnt get added, so free the entry */
|
|
goto devinit_err;
|
|
}
|
|
list_add(&dev->list, &blkmtd_device_list);
|
|
INFO("mtd%d: [%s] erase_size = %dKiB [%d]", dev->mtd.index,
|
|
dev->mtd.name + strlen("blkmtd: "),
|
|
dev->mtd.erasesize >> 10, dev->mtd.erasesize);
|
|
return dev;
|
|
|
|
devinit_err:
|
|
block2mtd_free_device(dev);
|
|
return NULL;
|
|
}
|
|
|
|
|
|
static int ustrtoul(const char *cp, char **endp, unsigned int base)
|
|
{
|
|
unsigned long result = simple_strtoul(cp, endp, base);
|
|
switch (**endp) {
|
|
case 'G' :
|
|
result *= 1024;
|
|
case 'M':
|
|
result *= 1024;
|
|
case 'k':
|
|
result *= 1024;
|
|
/* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
|
|
if ((*endp)[1] == 'i')
|
|
(*endp) += 2;
|
|
}
|
|
return result;
|
|
}
|
|
|
|
|
|
static int parse_num(size_t *num, const char *token)
|
|
{
|
|
char *endp;
|
|
size_t n;
|
|
|
|
n = (size_t) ustrtoul(token, &endp, 0);
|
|
if (*endp)
|
|
return -EINVAL;
|
|
|
|
*num = n;
|
|
return 0;
|
|
}
|
|
|
|
|
|
static int parse_name(char **pname, const char *token, size_t limit)
|
|
{
|
|
size_t len;
|
|
char *name;
|
|
|
|
len = strlen(token) + 1;
|
|
if (len > limit)
|
|
return -ENOSPC;
|
|
|
|
name = kmalloc(len, GFP_KERNEL);
|
|
if (!name)
|
|
return -ENOMEM;
|
|
|
|
strcpy(name, token);
|
|
|
|
*pname = name;
|
|
return 0;
|
|
}
|
|
|
|
|
|
static inline void kill_final_newline(char *str)
|
|
{
|
|
char *newline = strrchr(str, '\n');
|
|
if (newline && !newline[1])
|
|
*newline = 0;
|
|
}
|
|
|
|
|
|
#define parse_err(fmt, args...) do { \
|
|
ERROR("block2mtd: " fmt "\n", ## args); \
|
|
return 0; \
|
|
} while (0)
|
|
|
|
static int block2mtd_setup(const char *val, struct kernel_param *kp)
|
|
{
|
|
char buf[80+12], *str=buf; /* 80 for device, 12 for erase size */
|
|
char *token[2];
|
|
char *name;
|
|
size_t erase_size = PAGE_SIZE;
|
|
int i, ret;
|
|
|
|
if (strnlen(val, sizeof(buf)) >= sizeof(buf))
|
|
parse_err("parameter too long");
|
|
|
|
strcpy(str, val);
|
|
kill_final_newline(str);
|
|
|
|
for (i=0; i<2; i++)
|
|
token[i] = strsep(&str, ",");
|
|
|
|
if (str)
|
|
parse_err("too many arguments");
|
|
|
|
if (!token[0])
|
|
parse_err("no argument");
|
|
|
|
ret = parse_name(&name, token[0], 80);
|
|
if (ret == -ENOMEM)
|
|
parse_err("out of memory");
|
|
if (ret == -ENOSPC)
|
|
parse_err("name too long");
|
|
if (ret)
|
|
return 0;
|
|
|
|
if (token[1]) {
|
|
ret = parse_num(&erase_size, token[1]);
|
|
if (ret)
|
|
parse_err("illegal erase size");
|
|
}
|
|
|
|
add_device(name, erase_size);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
module_param_call(block2mtd, block2mtd_setup, NULL, NULL, 0200);
|
|
MODULE_PARM_DESC(block2mtd, "Device to use. \"block2mtd=<dev>[,<erasesize>]\"");
|
|
|
|
static int __init block2mtd_init(void)
|
|
{
|
|
INFO("version " VERSION);
|
|
return 0;
|
|
}
|
|
|
|
|
|
static void __devexit block2mtd_exit(void)
|
|
{
|
|
struct list_head *pos, *next;
|
|
|
|
/* Remove the MTD devices */
|
|
list_for_each_safe(pos, next, &blkmtd_device_list) {
|
|
struct block2mtd_dev *dev = list_entry(pos, typeof(*dev), list);
|
|
block2mtd_sync(&dev->mtd);
|
|
del_mtd_device(&dev->mtd);
|
|
INFO("mtd%d: [%s] removed", dev->mtd.index,
|
|
dev->mtd.name + strlen("blkmtd: "));
|
|
list_del(&dev->list);
|
|
block2mtd_free_device(dev);
|
|
}
|
|
}
|
|
|
|
|
|
module_init(block2mtd_init);
|
|
module_exit(block2mtd_exit);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Simon Evans <spse@secret.org.uk> and others");
|
|
MODULE_DESCRIPTION("Emulate an MTD using a block device");
|