497 строки
11 KiB
C
497 строки
11 KiB
C
/*
|
|
* block2mtd.c - create an mtd from a block device
|
|
*
|
|
* Copyright (C) 2001,2002 Simon Evans <spse@secret.org.uk>
|
|
* Copyright (C) 2004-2006 Joern Engel <joern@wh.fh-wedel.de>
|
|
*
|
|
* Licence: GPL
|
|
*/
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
|
|
/*
|
|
* When the first attempt at device initialization fails, we may need to
|
|
* wait a little bit and retry. This timeout, by default 3 seconds, gives
|
|
* device time to start up. Required on BCM2708 and a few other chipsets.
|
|
*/
|
|
#define MTD_DEFAULT_TIMEOUT 3
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/delay.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/backing-dev.h>
|
|
#include <linux/bio.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/list.h>
|
|
#include <linux/init.h>
|
|
#include <linux/mtd/mtd.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/mount.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/major.h>
|
|
|
|
/* Info for the block device */
|
|
struct block2mtd_dev {
|
|
struct list_head list;
|
|
struct block_device *blkdev;
|
|
struct mtd_info mtd;
|
|
struct mutex write_mutex;
|
|
};
|
|
|
|
|
|
/* Static info about the MTD, used in cleanup_module */
|
|
static LIST_HEAD(blkmtd_device_list);
|
|
|
|
|
|
static struct page *page_read(struct address_space *mapping, int index)
|
|
{
|
|
return read_mapping_page(mapping, index, 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_read(mapping, index);
|
|
if (IS_ERR(page))
|
|
return PTR_ERR(page);
|
|
|
|
max = page_address(page) + PAGE_SIZE;
|
|
for (p=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);
|
|
balance_dirty_pages_ratelimited(mapping);
|
|
break;
|
|
}
|
|
|
|
put_page(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;
|
|
|
|
mutex_lock(&dev->write_mutex);
|
|
err = _block2mtd_erase(dev, from, len);
|
|
mutex_unlock(&dev->write_mutex);
|
|
if (err)
|
|
pr_err("erase failed err = %d\n", err);
|
|
|
|
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;
|
|
|
|
while (len) {
|
|
if ((offset + len) > PAGE_SIZE)
|
|
cpylen = PAGE_SIZE - offset; // multiple pages
|
|
else
|
|
cpylen = len; // this page
|
|
len = len - cpylen;
|
|
|
|
page = page_read(dev->blkdev->bd_inode->i_mapping, index);
|
|
if (IS_ERR(page))
|
|
return PTR_ERR(page);
|
|
|
|
memcpy(buf, page_address(page) + offset, cpylen);
|
|
put_page(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;
|
|
|
|
while (len) {
|
|
if ((offset+len) > PAGE_SIZE)
|
|
cpylen = PAGE_SIZE - offset; // multiple pages
|
|
else
|
|
cpylen = len; // this page
|
|
len = len - cpylen;
|
|
|
|
page = page_read(mapping, index);
|
|
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);
|
|
balance_dirty_pages_ratelimited(mapping);
|
|
}
|
|
put_page(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;
|
|
|
|
mutex_lock(&dev->write_mutex);
|
|
err = _block2mtd_write(dev, buf, to, len, retlen);
|
|
mutex_unlock(&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_mapping_pages(dev->blkdev->bd_inode->i_mapping,
|
|
0, -1);
|
|
blkdev_put(dev->blkdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
|
|
}
|
|
|
|
kfree(dev);
|
|
}
|
|
|
|
|
|
static struct block2mtd_dev *add_device(char *devname, int erase_size,
|
|
int timeout)
|
|
{
|
|
#ifndef MODULE
|
|
int i;
|
|
#endif
|
|
const fmode_t mode = FMODE_READ | FMODE_WRITE | FMODE_EXCL;
|
|
struct block_device *bdev;
|
|
struct block2mtd_dev *dev;
|
|
char *name;
|
|
|
|
if (!devname)
|
|
return NULL;
|
|
|
|
dev = kzalloc(sizeof(struct block2mtd_dev), GFP_KERNEL);
|
|
if (!dev)
|
|
return NULL;
|
|
|
|
/* Get a handle on the device */
|
|
bdev = blkdev_get_by_path(devname, mode, dev);
|
|
|
|
#ifndef MODULE
|
|
/*
|
|
* We might not have the root device mounted at this point.
|
|
* Try to resolve the device name by other means.
|
|
*/
|
|
for (i = 0; IS_ERR(bdev) && i <= timeout; i++) {
|
|
dev_t devt;
|
|
|
|
if (i)
|
|
/*
|
|
* Calling wait_for_device_probe in the first loop
|
|
* was not enough, sleep for a bit in subsequent
|
|
* go-arounds.
|
|
*/
|
|
msleep(1000);
|
|
wait_for_device_probe();
|
|
|
|
devt = name_to_dev_t(devname);
|
|
if (!devt)
|
|
continue;
|
|
bdev = blkdev_get_by_dev(devt, mode, dev);
|
|
}
|
|
#endif
|
|
|
|
if (IS_ERR(bdev)) {
|
|
pr_err("error: cannot open device %s\n", devname);
|
|
goto err_free_block2mtd;
|
|
}
|
|
dev->blkdev = bdev;
|
|
|
|
if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
|
|
pr_err("attempting to use an MTD device as a block device\n");
|
|
goto err_free_block2mtd;
|
|
}
|
|
|
|
if ((long)dev->blkdev->bd_inode->i_size % erase_size) {
|
|
pr_err("erasesize must be a divisor of device size\n");
|
|
goto err_free_block2mtd;
|
|
}
|
|
|
|
mutex_init(&dev->write_mutex);
|
|
|
|
/* Setup the MTD structure */
|
|
/* make the name contain the block device in */
|
|
name = kasprintf(GFP_KERNEL, "block2mtd: %s", devname);
|
|
if (!name)
|
|
goto err_destroy_mutex;
|
|
|
|
dev->mtd.name = name;
|
|
|
|
dev->mtd.size = dev->blkdev->bd_inode->i_size & PAGE_MASK;
|
|
dev->mtd.erasesize = erase_size;
|
|
dev->mtd.writesize = 1;
|
|
dev->mtd.writebufsize = PAGE_SIZE;
|
|
dev->mtd.type = MTD_RAM;
|
|
dev->mtd.flags = MTD_CAP_RAM;
|
|
dev->mtd._erase = block2mtd_erase;
|
|
dev->mtd._write = block2mtd_write;
|
|
dev->mtd._sync = block2mtd_sync;
|
|
dev->mtd._read = block2mtd_read;
|
|
dev->mtd.priv = dev;
|
|
dev->mtd.owner = THIS_MODULE;
|
|
|
|
if (mtd_device_register(&dev->mtd, NULL, 0)) {
|
|
/* Device didn't get added, so free the entry */
|
|
goto err_destroy_mutex;
|
|
}
|
|
|
|
list_add(&dev->list, &blkmtd_device_list);
|
|
pr_info("mtd%d: [%s] erase_size = %dKiB [%d]\n",
|
|
dev->mtd.index,
|
|
dev->mtd.name + strlen("block2mtd: "),
|
|
dev->mtd.erasesize >> 10, dev->mtd.erasesize);
|
|
return dev;
|
|
|
|
err_destroy_mutex:
|
|
mutex_destroy(&dev->write_mutex);
|
|
err_free_block2mtd:
|
|
block2mtd_free_device(dev);
|
|
return NULL;
|
|
}
|
|
|
|
|
|
/* This function works similar to reguler strtoul. In addition, it
|
|
* allows some suffixes for a more human-readable number format:
|
|
* ki, Ki, kiB, KiB - multiply result with 1024
|
|
* Mi, MiB - multiply result with 1024^2
|
|
* Gi, GiB - multiply result with 1024^3
|
|
*/
|
|
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':
|
|
case 'k':
|
|
result *= 1024;
|
|
/* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
|
|
if ((*endp)[1] == 'i') {
|
|
if ((*endp)[2] == 'B')
|
|
(*endp) += 3;
|
|
else
|
|
(*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 inline void kill_final_newline(char *str)
|
|
{
|
|
char *newline = strrchr(str, '\n');
|
|
if (newline && !newline[1])
|
|
*newline = 0;
|
|
}
|
|
|
|
|
|
#ifndef MODULE
|
|
static int block2mtd_init_called = 0;
|
|
/* 80 for device, 12 for erase size */
|
|
static char block2mtd_paramline[80 + 12];
|
|
#endif
|
|
|
|
static int block2mtd_setup2(const char *val)
|
|
{
|
|
/* 80 for device, 12 for erase size, 80 for name, 8 for timeout */
|
|
char buf[80 + 12 + 80 + 8];
|
|
char *str = buf;
|
|
char *token[2];
|
|
char *name;
|
|
size_t erase_size = PAGE_SIZE;
|
|
unsigned long timeout = MTD_DEFAULT_TIMEOUT;
|
|
int i, ret;
|
|
|
|
if (strnlen(val, sizeof(buf)) >= sizeof(buf)) {
|
|
pr_err("parameter too long\n");
|
|
return 0;
|
|
}
|
|
|
|
strcpy(str, val);
|
|
kill_final_newline(str);
|
|
|
|
for (i = 0; i < 2; i++)
|
|
token[i] = strsep(&str, ",");
|
|
|
|
if (str) {
|
|
pr_err("too many arguments\n");
|
|
return 0;
|
|
}
|
|
|
|
if (!token[0]) {
|
|
pr_err("no argument\n");
|
|
return 0;
|
|
}
|
|
|
|
name = token[0];
|
|
if (strlen(name) + 1 > 80) {
|
|
pr_err("device name too long\n");
|
|
return 0;
|
|
}
|
|
|
|
if (token[1]) {
|
|
ret = parse_num(&erase_size, token[1]);
|
|
if (ret) {
|
|
pr_err("illegal erase size\n");
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
add_device(name, erase_size, timeout);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
static int block2mtd_setup(const char *val, const struct kernel_param *kp)
|
|
{
|
|
#ifdef MODULE
|
|
return block2mtd_setup2(val);
|
|
#else
|
|
/* If more parameters are later passed in via
|
|
/sys/module/block2mtd/parameters/block2mtd
|
|
and block2mtd_init() has already been called,
|
|
we can parse the argument now. */
|
|
|
|
if (block2mtd_init_called)
|
|
return block2mtd_setup2(val);
|
|
|
|
/* During early boot stage, we only save the parameters
|
|
here. We must parse them later: if the param passed
|
|
from kernel boot command line, block2mtd_setup() is
|
|
called so early that it is not possible to resolve
|
|
the device (even kmalloc() fails). Deter that work to
|
|
block2mtd_setup2(). */
|
|
|
|
strlcpy(block2mtd_paramline, val, sizeof(block2mtd_paramline));
|
|
|
|
return 0;
|
|
#endif
|
|
}
|
|
|
|
|
|
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)
|
|
{
|
|
int ret = 0;
|
|
|
|
#ifndef MODULE
|
|
if (strlen(block2mtd_paramline))
|
|
ret = block2mtd_setup2(block2mtd_paramline);
|
|
block2mtd_init_called = 1;
|
|
#endif
|
|
|
|
return ret;
|
|
}
|
|
|
|
|
|
static void 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);
|
|
mtd_device_unregister(&dev->mtd);
|
|
mutex_destroy(&dev->write_mutex);
|
|
pr_info("mtd%d: [%s] removed\n",
|
|
dev->mtd.index,
|
|
dev->mtd.name + strlen("block2mtd: "));
|
|
list_del(&dev->list);
|
|
block2mtd_free_device(dev);
|
|
}
|
|
}
|
|
|
|
late_initcall(block2mtd_init);
|
|
module_exit(block2mtd_exit);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Joern Engel <joern@lazybastard.org>");
|
|
MODULE_DESCRIPTION("Emulate an MTD using a block device");
|