blob: 4c16c0e43e0fde4a1cc6aff8d7137c8791499f9f [file] [log] [blame]
/*
* MTD device concatenation layer
*
* (C) 2002 Robert Kaiser <rkaiser@sysgo.de>
*
* This code is GPL
*
* $Id: mtdconcat.c,v 1.3 2002/05/21 21:04:25 dwmw2 Exp $
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/concat.h>
/*
* Our storage structure:
* Subdev points to an array of pointers to struct mtd_info objects
* which is allocated along with this structure
*
*/
struct mtd_concat {
struct mtd_info mtd;
int num_subdev;
struct mtd_info **subdev;
};
/*
* how to calculate the size required for the above structure,
* including the pointer array subdev points to:
*/
#define SIZEOF_STRUCT_MTD_CONCAT(num_subdev) \
((sizeof(struct mtd_concat) + (num_subdev) * sizeof(struct mtd_info *)))
/*
* Given a pointer to the MTD object in the mtd_concat structure,
* we can retrieve the pointer to that structure with this macro.
*/
#define CONCAT(x) ((struct mtd_concat *)(x))
/*
* MTD methods which look up the relevant subdevice, translate the
* effective address and pass through to the subdevice.
*/
static int concat_read (struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, u_char *buf)
{
struct mtd_concat *concat = CONCAT(mtd);
int err = -EINVAL;
int i;
*retlen = 0;
for(i = 0; i < concat->num_subdev; i++)
{
struct mtd_info *subdev = concat->subdev[i];
size_t size, retsize;
if (from >= subdev->size)
{
size = 0;
from -= subdev->size;
}
else
{
if (from + len > subdev->size)
size = subdev->size - from;
else
size = len;
err = subdev->read(subdev, from, size, &retsize, buf);
if(err)
break;
*retlen += retsize;
len -= size;
if(len == 0)
break;
err = -EINVAL;
buf += size;
from = 0;
}
}
return err;
}
static int concat_write (struct mtd_info *mtd, loff_t to, size_t len,
size_t *retlen, const u_char *buf)
{
struct mtd_concat *concat = CONCAT(mtd);
int err = -EINVAL;
int i;
if (!(mtd->flags & MTD_WRITEABLE))
return -EROFS;
*retlen = 0;
for(i = 0; i < concat->num_subdev; i++)
{
struct mtd_info *subdev = concat->subdev[i];
size_t size, retsize;
if (to >= subdev->size)
{
size = 0;
to -= subdev->size;
}
else
{
if (to + len > subdev->size)
size = subdev->size - to;
else
size = len;
if (!(subdev->flags & MTD_WRITEABLE))
err = -EROFS;
else
err = subdev->write(subdev, to, size, &retsize, buf);
if(err)
break;
*retlen += retsize;
len -= size;
if(len == 0)
break;
err = -EINVAL;
buf += size;
to = 0;
}
}
return err;
}
static void concat_erase_callback (struct erase_info *instr)
{
wake_up((wait_queue_head_t *)instr->priv);
}
static int concat_dev_erase(struct mtd_info *mtd, struct erase_info *erase)
{
int err;
wait_queue_head_t waitq;
DECLARE_WAITQUEUE(wait, current);
/*
* This code was stol^H^H^H^Hinspired by mtdchar.c
*/
init_waitqueue_head(&waitq);
erase->mtd = mtd;
erase->callback = concat_erase_callback;
erase->priv = (unsigned long)&waitq;
/*
* FIXME: Allow INTERRUPTIBLE. Which means
* not having the wait_queue head on the stack.
*/
err = mtd->erase(mtd, erase);
if (!err)
{
set_current_state(TASK_UNINTERRUPTIBLE);
add_wait_queue(&waitq, &wait);
if (erase->state != MTD_ERASE_DONE && erase->state != MTD_ERASE_FAILED)
schedule();
remove_wait_queue(&waitq, &wait);
set_current_state(TASK_RUNNING);
err = (erase->state == MTD_ERASE_FAILED) ? -EIO : 0;
}
return err;
}
static int concat_erase (struct mtd_info *mtd, struct erase_info *instr)
{
struct mtd_concat *concat = CONCAT(mtd);
struct mtd_info *subdev;
int i, err;
u_int32_t length;
struct erase_info *erase;
if (!(mtd->flags & MTD_WRITEABLE))
return -EROFS;
if(instr->addr > concat->mtd.size)
return -EINVAL;
if(instr->len + instr->addr > concat->mtd.size)
return -EINVAL;
/*
* Check for proper erase block alignment of the to-be-erased area.
* It is easier to do this based on the super device's erase
* region info rather than looking at each particular sub-device
* in turn.
*/
if (!concat->mtd.numeraseregions)
{ /* the easy case: device has uniform erase block size */
if(instr->addr & (concat->mtd.erasesize - 1))
return -EINVAL;
if(instr->len & (concat->mtd.erasesize - 1))
return -EINVAL;
}
else
{ /* device has variable erase size */
struct mtd_erase_region_info *erase_regions = concat->mtd.eraseregions;
/*
* Find the erase region where the to-be-erased area begins:
*/
for(i = 0; i < concat->mtd.numeraseregions &&
instr->addr >= erase_regions[i].offset; i++)
;
--i;
/*
* Now erase_regions[i] is the region in which the
* to-be-erased area begins. Verify that the starting
* offset is aligned to this region's erase size:
*/
if (instr->addr & (erase_regions[i].erasesize-1))
return -EINVAL;
/*
* now find the erase region where the to-be-erased area ends:
*/
for(; i < concat->mtd.numeraseregions &&
(instr->addr + instr->len) >= erase_regions[i].offset ; ++i)
;
--i;
/*
* check if the ending offset is aligned to this region's erase size
*/
if ((instr->addr + instr->len) & (erase_regions[i].erasesize-1))
return -EINVAL;
}
/* make a local copy of instr to avoid modifying the caller's struct */
erase = kmalloc(sizeof(struct erase_info),GFP_KERNEL);
if (!erase)
return -ENOMEM;
*erase = *instr;
length = instr->len;
/*
* find the subdevice where the to-be-erased area begins, adjust
* starting offset to be relative to the subdevice start
*/
for(i = 0; i < concat->num_subdev; i++)
{
subdev = concat->subdev[i];
if(subdev->size <= erase->addr)
erase->addr -= subdev->size;
else
break;
}
if(i >= concat->num_subdev) /* must never happen since size */
BUG(); /* limit has been verified above */
/* now do the erase: */
err = 0;
for(;length > 0; i++) /* loop for all subevices affected by this request */
{
subdev = concat->subdev[i]; /* get current subdevice */
/* limit length to subdevice's size: */
if(erase->addr + length > subdev->size)
erase->len = subdev->size - erase->addr;
else
erase->len = length;
if (!(subdev->flags & MTD_WRITEABLE))
{
err = -EROFS;
break;
}
length -= erase->len;
if ((err = concat_dev_erase(subdev, erase)))
{
if(err == -EINVAL) /* sanity check: must never happen since */
BUG(); /* block alignment has been checked above */
break;
}
/*
* erase->addr specifies the offset of the area to be
* erased *within the current subdevice*. It can be
* non-zero only the first time through this loop, i.e.
* for the first subdevice where blocks need to be erased.
* All the following erases must begin at the start of the
* current subdevice, i.e. at offset zero.
*/
erase->addr = 0;
}
kfree(erase);
if (err)
return err;
instr->state = MTD_ERASE_DONE;
if (instr->callback)
instr->callback(instr);
return 0;
}
static int concat_lock (struct mtd_info *mtd, loff_t ofs, size_t len)
{
struct mtd_concat *concat = CONCAT(mtd);
int i, err = -EINVAL;
if ((len + ofs) > mtd->size)
return -EINVAL;
for(i = 0; i < concat->num_subdev; i++)
{
struct mtd_info *subdev = concat->subdev[i];
size_t size;
if (ofs >= subdev->size)
{
size = 0;
ofs -= subdev->size;
}
else
{
if (ofs + len > subdev->size)
size = subdev->size - ofs;
else
size = len;
err = subdev->lock(subdev, ofs, size);
if(err)
break;
len -= size;
if(len == 0)
break;
err = -EINVAL;
ofs = 0;
}
}
return err;
}
static int concat_unlock (struct mtd_info *mtd, loff_t ofs, size_t len)
{
struct mtd_concat *concat = CONCAT(mtd);
int i, err = 0;
if ((len + ofs) > mtd->size)
return -EINVAL;
for(i = 0; i < concat->num_subdev; i++)
{
struct mtd_info *subdev = concat->subdev[i];
size_t size;
if (ofs >= subdev->size)
{
size = 0;
ofs -= subdev->size;
}
else
{
if (ofs + len > subdev->size)
size = subdev->size - ofs;
else
size = len;
err = subdev->unlock(subdev, ofs, size);
if(err)
break;
len -= size;
if(len == 0)
break;
err = -EINVAL;
ofs = 0;
}
}
return err;
}
static void concat_sync(struct mtd_info *mtd)
{
struct mtd_concat *concat = CONCAT(mtd);
int i;
for(i = 0; i < concat->num_subdev; i++)
{
struct mtd_info *subdev = concat->subdev[i];
subdev->sync(subdev);
}
}
static int concat_suspend(struct mtd_info *mtd)
{
struct mtd_concat *concat = CONCAT(mtd);
int i, rc = 0;
for(i = 0; i < concat->num_subdev; i++)
{
struct mtd_info *subdev = concat->subdev[i];
if((rc = subdev->suspend(subdev)) < 0)
return rc;
}
return rc;
}
static void concat_resume(struct mtd_info *mtd)
{
struct mtd_concat *concat = CONCAT(mtd);
int i;
for(i = 0; i < concat->num_subdev; i++)
{
struct mtd_info *subdev = concat->subdev[i];
subdev->resume(subdev);
}
}
/*
* This function constructs a virtual MTD device by concatenating
* num_devs MTD devices. A pointer to the new device object is
* stored to *new_dev upon success. This function does _not_
* register any devices: this is the caller's responsibility.
*/
struct mtd_info *mtd_concat_create(
struct mtd_info *subdev[], /* subdevices to concatenate */
int num_devs, /* number of subdevices */
char *name) /* name for the new device */
{
int i;
size_t size;
struct mtd_concat *concat;
u_int32_t max_erasesize, curr_erasesize;
int num_erase_region;
printk(KERN_NOTICE "Concatenating MTD devices:\n");
for(i = 0; i < num_devs; i++)
printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
printk(KERN_NOTICE "into device \"%s\"\n", name);
/* allocate the device structure */
size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);
concat = kmalloc (size, GFP_KERNEL);
if(!concat)
{
printk ("memory allocation error while creating concatenated device \"%s\"\n",
name);
return NULL;
}
memset(concat, 0, size);
concat->subdev = (struct mtd_info **)(concat + 1);
/*
* Set up the new "super" device's MTD object structure, check for
* incompatibilites between the subdevices.
*/
concat->mtd.type = subdev[0]->type;
concat->mtd.flags = subdev[0]->flags;
concat->mtd.size = subdev[0]->size;
concat->mtd.erasesize = subdev[0]->erasesize;
concat->mtd.oobblock = subdev[0]->oobblock;
concat->mtd.oobsize = subdev[0]->oobsize;
concat->mtd.ecctype = subdev[0]->ecctype;
concat->mtd.eccsize = subdev[0]->eccsize;
concat->subdev[0] = subdev[0];
for(i = 1; i < num_devs; i++)
{
if(concat->mtd.type != subdev[i]->type)
{
kfree(concat);
printk ("Incompatible device type on \"%s\"\n", subdev[i]->name);
return NULL;
}
if(concat->mtd.flags != subdev[i]->flags)
{ /*
* Expect all flags except MTD_WRITEABLE to be equal on
* all subdevices.
*/
if((concat->mtd.flags ^ subdev[i]->flags) & ~MTD_WRITEABLE)
{
kfree(concat);
printk ("Incompatible device flags on \"%s\"\n", subdev[i]->name);
return NULL;
}
else /* if writeable attribute differs, make super device writeable */
concat->mtd.flags |= subdev[i]->flags & MTD_WRITEABLE;
}
concat->mtd.size += subdev[i]->size;
if(concat->mtd.oobblock != subdev[i]->oobblock ||
concat->mtd.oobsize != subdev[i]->oobsize ||
concat->mtd.ecctype != subdev[i]->ecctype ||
concat->mtd.eccsize != subdev[i]->eccsize)
{
kfree(concat);
printk ("Incompatible OOB or ECC data on \"%s\"\n", subdev[i]->name);
return NULL;
}
concat->subdev[i] = subdev[i];
}
concat->num_subdev = num_devs;
concat->mtd.name = name;
/*
* NOTE: for now, we do not provide any readv()/writev() methods
* because they are messy to implement and they are not
* used to a great extent anyway.
*/
concat->mtd.erase = concat_erase;
concat->mtd.read = concat_read;
concat->mtd.write = concat_write;
concat->mtd.sync = concat_sync;
concat->mtd.lock = concat_lock;
concat->mtd.unlock = concat_unlock;
concat->mtd.suspend = concat_suspend;
concat->mtd.resume = concat_resume;
/*
* Combine the erase block size info of the subdevices:
*
* first, walk the map of the new device and see how
* many changes in erase size we have
*/
max_erasesize = curr_erasesize = subdev[0]->erasesize;
num_erase_region = 1;
for(i = 0; i < num_devs; i++)
{
if(subdev[i]->numeraseregions == 0)
{ /* current subdevice has uniform erase size */
if(subdev[i]->erasesize != curr_erasesize)
{ /* if it differs from the last subdevice's erase size, count it */
++num_erase_region;
curr_erasesize = subdev[i]->erasesize;
if(curr_erasesize > max_erasesize)
max_erasesize = curr_erasesize;
}
}
else
{ /* current subdevice has variable erase size */
int j;
for(j = 0; j < subdev[i]->numeraseregions; j++)
{ /* walk the list of erase regions, count any changes */
if(subdev[i]->eraseregions[j].erasesize != curr_erasesize)
{
++num_erase_region;
curr_erasesize = subdev[i]->eraseregions[j].erasesize;
if(curr_erasesize > max_erasesize)
max_erasesize = curr_erasesize;
}
}
}
}
if(num_erase_region == 1)
{ /*
* All subdevices have the same uniform erase size.
* This is easy:
*/
concat->mtd.erasesize = curr_erasesize;
concat->mtd.numeraseregions = 0;
}
else
{ /*
* erase block size varies across the subdevices: allocate
* space to store the data describing the variable erase regions
*/
struct mtd_erase_region_info *erase_region_p;
u_int32_t begin, position;
concat->mtd.erasesize = max_erasesize;
concat->mtd.numeraseregions = num_erase_region;
concat->mtd.eraseregions = erase_region_p = kmalloc (
num_erase_region * sizeof(struct mtd_erase_region_info), GFP_KERNEL);
if(!erase_region_p)
{
kfree(concat);
printk ("memory allocation error while creating erase region list"
" for device \"%s\"\n", name);
return NULL;
}
/*
* walk the map of the new device once more and fill in
* in erase region info:
*/
curr_erasesize = subdev[0]->erasesize;
begin = position = 0;
for(i = 0; i < num_devs; i++)
{
if(subdev[i]->numeraseregions == 0)
{ /* current subdevice has uniform erase size */
if(subdev[i]->erasesize != curr_erasesize)
{ /*
* fill in an mtd_erase_region_info structure for the area
* we have walked so far:
*/
erase_region_p->offset = begin;
erase_region_p->erasesize = curr_erasesize;
erase_region_p->numblocks = (position - begin) / curr_erasesize;
begin = position;
curr_erasesize = subdev[i]->erasesize;
++erase_region_p;
}
position += subdev[i]->size;
}
else
{ /* current subdevice has variable erase size */
int j;
for(j = 0; j < subdev[i]->numeraseregions; j++)
{ /* walk the list of erase regions, count any changes */
if(subdev[i]->eraseregions[j].erasesize != curr_erasesize)
{
erase_region_p->offset = begin;
erase_region_p->erasesize = curr_erasesize;
erase_region_p->numblocks = (position - begin) / curr_erasesize;
begin = position;
curr_erasesize = subdev[i]->eraseregions[j].erasesize;
++erase_region_p;
}
position += subdev[i]->eraseregions[j].numblocks * curr_erasesize;
}
}
}
/* Now write the final entry */
erase_region_p->offset = begin;
erase_region_p->erasesize = curr_erasesize;
erase_region_p->numblocks = (position - begin) / curr_erasesize;
}
return &concat->mtd;
}
/*
* This function destroys an MTD object obtained from concat_mtd_devs()
*/
void mtd_concat_destroy(struct mtd_info *mtd)
{
struct mtd_concat *concat = CONCAT(mtd);
if(concat->mtd.numeraseregions)
kfree(concat->mtd.eraseregions);
kfree(concat);
}
EXPORT_SYMBOL(mtd_concat_create);
EXPORT_SYMBOL(mtd_concat_destroy);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");
MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");