/*
* Copyright (c) International Business Machines Corp., 2006
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Author: Artem Bityutskiy (Битюцкий Артём), Joern Engel
*/
/*
* This file includes implementation of fake MTD devices for each UBI volume.
* This sounds strange, but it is in fact quite useful to make MTD-oriented
* software (including all the legacy software) to work on top of UBI.
*
* Gluebi emulates MTD devices of "MTD_UBIVOLUME" type. Their minimal I/O unit
* size (mtd->writesize) is equivalent to the UBI minimal I/O unit. The
* eraseblock size is equivalent to the logical eraseblock size of the volume.
*/
#include <linux/math64.h>
#include "ubi.h"
/**
* gluebi_get_device - get MTD device reference.
* @mtd: the MTD device description object
*
* This function is called every time the MTD device is being opened and
* implements the MTD get_device() operation. Returns zero in case of success
* and a negative error code in case of failure.
*/
static int gluebi_get_device(struct mtd_info *mtd)
{
struct ubi_volume *vol;
vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
/*
* We do not introduce locks for gluebi reference count because the
* get_device()/put_device() calls are already serialized at MTD.
*/
if (vol->gluebi_refcount > 0) {
/*
* The MTD device is already referenced and this is just one
* more reference. MTD allows many users to open the same
* volume simultaneously and do not distinguish between
* readers/writers/exclusive openers as UBI does. So we do not
* open the UBI volume again - just increase the reference
* counter and return.
*/
vol->gluebi_refcount += 1;
return 0;
}
/*
* This is the first reference to this UBI volume via the MTD device
* interface. Open the corresponding volume in read-write mode.
*/
vol->gluebi_desc = ubi_open_volume(vol->ubi->ubi_num, vol->vol_id,
UBI_READWRITE);
if (IS_ERR(vol->gluebi_desc))
return PTR_ERR(vol->gluebi_desc);
vol->gluebi_refcount += 1;
return 0;
}
/**
* gluebi_put_device - put MTD device reference.
* @mtd: the MTD device description object
*
* This function is called every time the MTD device is being put. Returns
* zero in case of success and a negative error code in case of failure.
*/
static void gluebi_put_device(struct mtd_info *mtd)
{
struct ubi_volume *vol;
vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
vol->gluebi_refcount -= 1;
ubi_assert(vol->gluebi_refcount >= 0);
if (vol->gluebi_refcount == 0)
ubi_close_volume(vol->gluebi_desc);
}
/**
* gluebi_read - read operation of emulated MTD devices.
* @mtd: MTD device description object
* @from: absolute offset from where to read
* @len: how many bytes to read
* @retlen: count of read bytes is returned here
* @buf: buffer to store the read data
*
* This function returns zero in case of success and a negative error code in
* case of failure.
*/
static int gluebi_read(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, unsigned char *buf)
{
int err = 0, lnum, offs, total_read;
struct ubi_volume *vol;
struct ubi_device *ubi;
dbg_gen("read %zd bytes from offset %lld", len, from);
if (len < 0 || from < 0 || from + len > mtd->size)
return -EINVAL;
vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
ubi = vol->ubi;
lnum = div_u64_rem(from, mtd->erasesize, &offs);
total_read = len;
while (total_read) {
size_t to_read = mtd->erasesize - offs;
if (to_read > total_read)
to_read = total_read;
err = ubi_eba_read_leb(ubi, vol, lnum, buf, offs, to_read, 0);
if (err)
break;
lnum += 1;
offs = 0;
total_read -= to_read;
buf += to_read;
}
*retlen = len - total_read;
return err;
}
/**
* gluebi_write - write operation of emulated MTD devices.
* @mtd: MTD device description object
* @to: absolute offset where to write
* @len: how many bytes to write
* @retlen: count of written bytes is returned here
* @buf: buffer with data to write
*
* This function returns zero in case of success and a negative error code in
* case of failure.
*/
static int gluebi_write(struct mtd_info *mtd, loff_t to, size_t len,
size_t *retlen, const u_char *buf)
{
int err = 0, lnum, offs, total_written;
struct ubi_volume *vol;
struct ubi_device *ubi;
dbg_gen("write %zd bytes to offset %lld", len, to);
if (len < 0 || to < 0 || len + to > mtd->size)
return -EINVAL;
vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
ubi = vol->ubi;
if (ubi->ro_mode)
return -EROFS;
lnum = div_u64_rem(to, mtd->erasesize, &offs);
if (len % mtd->writesize || offs % mtd->writesize)
return -EINVAL;
total_written = len;
while (total_written) {
size_t to_write = mtd->erasesize - offs;
if (to_write > total_written)
to_write = total_written;
err = ubi_eba_write_leb(ubi, vol, lnum, buf, offs, to_write,
UBI_UNKNOWN);
if (err)
break;
lnum += 1;
offs = 0;
total_written -= to_write;
buf += to_write;
}
*retlen = len - total_written;
return err;
}
/**
* gluebi_erase - erase operation of emulated MTD devices.
* @mtd: the MTD device description object
* @instr: the erase operation description
*
* This function calls the erase callback when finishes. Returns zero in case
* of success and a negative error code in case of failure.
*/
static int gluebi_erase(struct mtd_info *mtd, struct erase_info *instr)
{
int err, i, lnum, count;
struct ubi_volume *vol;
struct ubi_device *ubi;
dbg_gen("erase %llu bytes at offset %llu", (unsigned long long)instr->len,
(unsigned long long)instr->addr);
if (instr->addr < 0 || instr->addr > mtd->size - mtd->erasesize)
return -EINVAL;
if (instr->len < 0 || instr->addr + instr->len > mtd->size)
return -EINVAL;
if (mtd_mod_by_ws(instr->addr, mtd) || mtd_mod_by_ws(instr->len, mtd))
return -EINVAL;
lnum = mtd_div_by_eb(instr->addr, mtd);
count = mtd_div_by_eb(instr->len, mtd);
vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
ubi = vol->ubi;
if (ubi->ro_mode)
return -EROFS;
for (i = 0; i < count; i++) {
err = ubi_eba_unmap_leb(ubi, vol, lnum + i);
if (err)
goto out_err;
}
/*
* MTD erase operations are synchronous, so we have to make sure the
* physical eraseblock is wiped out.
*/
err = ubi_wl_flush(ubi);
if (err)
goto out_err;
instr->state = MTD_ERASE_DONE;
mtd_erase_callback(instr);
return 0;
out_err:
instr->state = MTD_ERASE_FAILED;
instr->fail_addr = (long long)lnum * mtd->erasesize;
return err;
}
/**
* ubi_create_gluebi - initialize gluebi for an UBI volume.
* @ubi: UBI device description object
* @vol: volume description object
*
* This function is called when an UBI volume is created in order to create
* corresponding fake MTD device. Returns zero in case of success and a
* negative error code in case of failure.
*/
int ubi_create_gluebi(struct ubi_device *ubi, struct ubi_volume *vol)
{
struct mtd_info *mtd = &vol->gluebi_mtd;
mtd->name = kmemdup(vol->name, vol->name_len + 1, GFP_KERNEL);
if (!mtd->name)
return -ENOMEM;
mtd->type = MTD_UBIVOLUME;
if (!ubi->ro_mode)
mtd->flags = MTD_WRITEABLE;
mtd->writesize = ubi->min_io_size;
mtd->owner = THIS_MODULE;
mtd->erasesize = vol->usable_leb_size;
mtd->read = gluebi_read;
mtd->write = gluebi_write;
mtd->erase = gluebi_erase;
mtd->get_device = gluebi_get_device;
mtd->put_device = gluebi_put_device;
/*
* In case of dynamic volume, MTD device size is just volume size. In
* case of a static volume the size is equivalent to the amount of data
* bytes.
*/
if (vol->vol_type == UBI_DYNAMIC_VOLUME)
mtd->size = (long long)vol->usable_leb_size * vol->reserved_pebs;
else
mtd->size = vol->used_bytes;
if (add_mtd_device(mtd)) {
ubi_err("cannot not add MTD device");
kfree(mtd->name);
return -ENFILE;
}
dbg_gen("added mtd%d (\"%s\"), size %llu, EB size %u",
mtd->index, mtd->name, (unsigned long long)mtd->size, mtd->erasesize);
return 0;
}
/**
* ubi_destroy_gluebi - close gluebi for an UBI volume.
* @vol: volume description object
*
* This function is called when an UBI volume is removed in order to remove
* corresponding fake MTD device. Returns zero in case of success and a
* negative error code in case of failure.
*/
int ubi_destroy_gluebi(struct ubi_volume *vol)
{
int err;
struct mtd_info *mtd = &vol->gluebi_mtd;
dbg_gen("remove mtd%d", mtd->index);
err = del_mtd_device(mtd);
if (err)
return err;
kfree(mtd->name);
return 0;
}
/**
* ubi_gluebi_updated - UBI volume was updated notifier.
* @vol: volume description object
*
* This function is called every time an UBI volume is updated. This function
* does nothing if volume @vol is dynamic, and changes MTD device size if the
* volume is static. This is needed because static volumes cannot be read past
* data they contain.
*/
void ubi_gluebi_updated(struct ubi_volume *vol)
{
struct mtd_info *mtd = &vol->gluebi_mtd;
if (vol->vol_type == UBI_STATIC_VOLUME)
mtd->size = vol->used_bytes;
}
