linux/drivers/mtd/ubi/gluebi.c
Adrian Hunter 69423d99fc [MTD] update internal API to support 64-bit device size
MTD internal API presently uses 32-bit values to represent
device size.  This patch updates them to 64-bits but leaves
the external API unchanged.  Extending the external API
is a separate issue for several reasons.  First, no one
needs it at the moment.  Secondly, whether the implementation
is done with IOCTLs, sysfs or both is still debated.  Thirdly
external API changes require the internal API to be accepted
first.

Note that although the MTD API will be able to support 64-bit
device sizes, existing drivers do not and are not required
to do so, although NAND base has been updated.

In general, changing from 32-bit to 64-bit values cause little
or no changes to the majority of the code with the following
exceptions:
    	- printk message formats
    	- division and modulus of 64-bit values
    	- NAND base support
	- 32-bit local variables used by mtdpart and mtdconcat
	- naughtily assuming one structure maps to another
	in MEMERASE ioctl

Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2008-12-10 13:37:21 +00:00

349 lines
9.5 KiB
C

/*
* 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 <asm/div64.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;
uint64_t tmp = from;
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;
offs = do_div(tmp, mtd->erasesize);
lnum = tmp;
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;
uint64_t tmp = to;
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;
offs = do_div(tmp, mtd->erasesize);
lnum = tmp;
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;
}