- 根目录:
- drivers
- mtd
- rfd_ftl.c
/*
* rfd_ftl.c -- resident flash disk (flash translation layer)
*
* Copyright © 2005 Sean Young <sean@mess.org>
*
* This type of flash translation layer (FTL) is used by the Embedded BIOS
* by General Software. It is known as the Resident Flash Disk (RFD), see:
*
* http://www.gensw.com/pages/prod/bios/rfd.htm
*
* based on ftl.c
*/
#include <linux/hdreg.h>
#include <linux/init.h>
#include <linux/mtd/blktrans.h>
#include <linux/mtd/mtd.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <asm/types.h>
static int block_size = 0;
module_param(block_size, int, 0);
MODULE_PARM_DESC(block_size, "Block size to use by RFD, defaults to erase unit size");
#define PREFIX "rfd_ftl: "
/* This major has been assigned by device@lanana.org */
#ifndef RFD_FTL_MAJOR
#define RFD_FTL_MAJOR 256
#endif
/* Maximum number of partitions in an FTL region */
#define PART_BITS 4
/* An erase unit should start with this value */
#define RFD_MAGIC 0x9193
/* the second value is 0xffff or 0xffc8; function unknown */
/* the third value is always 0xffff, ignored */
/* next is an array of mapping for each corresponding sector */
#define HEADER_MAP_OFFSET 3
#define SECTOR_DELETED 0x0000
#define SECTOR_ZERO 0xfffe
#define SECTOR_FREE 0xffff
#define SECTOR_SIZE 512
#define SECTORS_PER_TRACK 63
struct block {
enum {
BLOCK_OK,
BLOCK_ERASING,
BLOCK_ERASED,
BLOCK_UNUSED,
BLOCK_FAILED
} state;
int free_sectors;
int used_sectors;
int erases;
u_long offset;
};
struct partition {
struct mtd_blktrans_dev mbd;
u_int block_size; /* size of erase unit */
u_int total_blocks; /* number of erase units */
u_int header_sectors_per_block; /* header sectors in erase unit */
u_int data_sectors_per_block; /* data sectors in erase unit */
u_int sector_count; /* sectors in translated disk */
u_int header_size; /* bytes in header sector */
int reserved_block; /* block next up for reclaim */
int current_block; /* block to write to */
u16 *header_cache; /* cached header */
int is_reclaiming;
int cylinders;
int errors;
u_long *sector_map;
struct block *blocks;
};
static int rfd_ftl_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf);
static int build_block_map(struct partition *part, int block_no)
{
struct block *block = &part->blocks[block_no];
int i;
block->offset = part->block_size * block_no;
if (le16_to_cpu(part->header_cache[0]) != RFD_MAGIC) {
block->state = BLOCK_UNUSED;
return -ENOENT;
}
block->state = BLOCK_OK;
for (i=0; i<part->data_sectors_per_block; i++) {
u16 entry;
entry = le16_to_cpu(part->header_cache[HEADER_MAP_OFFSET + i]);
if (entry == SECTOR_DELETED)
continue;
if (entry == SECTOR_FREE) {
block->free_sectors++;
continue;
}
if (entry == SECTOR_ZERO)
entry = 0;
if (entry >= part->sector_count) {
printk(KERN_WARNING PREFIX
"'%s': unit #%d: entry %d corrupt, "
"sector %d out of range\n",
part->mbd.mtd->name, block_no, i, entry);
continue;
}
if (part->sector_map[entry] != -1) {
printk(KERN_WARNING PREFIX
"'%s': more than one entry for sector %d\n",
part->mbd.mtd->name, entry);
part->errors = 1;
continue;
}
part->sector_map[entry] = block->offset +
(i + part->header_sectors_per_block) * SECTOR_SIZE;
block->used_sectors++;
}
if (block->free_sectors == part->data_sectors_per_block)
part->reserved_block = block_no;
return 0;
}
static int scan_header(struct partition *part)
{
int sectors_per_block;
int i, rc = -ENOMEM;
int blocks_found;
size_t retlen;
sectors_per_block = part->block_size / SECTOR_SIZE;
part->total_blocks = (u32)part->mbd.mtd->size / part->block_size;
if (part->total_blocks < 2)
return -ENOENT;
/* each erase block has three bytes header, followed by the map */
part->header_sectors_per_block =
((HEADER_MAP_OFFSET + sectors_per_block) *
sizeof(u16) + SECTOR_SIZE - 1) / SECTOR_SIZE;
part->data_sectors_per_block = sectors_per_block -
part->header_sectors_per_block;
part->header_size = (HEADER_MAP_OFFSET +
part->data_sectors_per_block) * sizeof(u16);
part->cylinders = (part->data_sectors_per_block *
(part->total_blocks - 1) - 1) / SECTORS_PER_TRACK;
part->sector_count = part->cylinders * SECTORS_PER_TRACK;
part->current_block = -1;
part->reserved_block = -1;
part->is_reclaiming = 0;
part->header_cache = kmalloc(part->header_size, GFP_KERNEL);
if (!part->header_cache)
goto err;
part->blocks = kcalloc(part->total_blocks, sizeof(struct block),
GFP_KERNEL);
if (!part->blocks)
goto err;
part->sector_map = vmalloc(part->sector_count * sizeof(u_long));
if (!part->sector_map) {
printk(KERN_ERR PREFIX "'%s': unable to allocate memory for "
"sector map", part->mbd.mtd->name);
goto err;
}
for (i=0; i<part->sector_count; i++)
part->sector_map[i] = -1;
for (i=0, blocks_found=0; i<part->total_blocks; i++) {
rc = mtd_read(part->mbd.mtd, i * part->block_size,
part->header_size, &retlen,
(u_char *)part->header_cache);
if (!rc && retlen != part->header_size)
rc = -EIO;
if (rc)
goto err;
if (!build_block_map(part, i))
blocks_found++;
}
if (blocks_found == 0) {
printk(KERN_NOTICE PREFIX "no RFD magic found in '%s'\n",
part->mbd.mtd->name);
rc = -ENOENT;
goto err;
}
if (part->reserved_block == -1) {
printk(KERN_WARNING PREFIX "'%s': no empty erase unit found\n",
part->mbd.mtd->name);
part->errors = 1;
}
return 0;
err:
vfree(part->sector_map);
kfree(part->header_cache);
kfree(part->blocks);
return rc;
}
static int rfd_ftl_readsect(struct mtd_blktrans_dev *dev, u_long sector, char *buf)
{
struct partition *part = (struct partition*)dev;
u_long addr;
size_t retlen;
int rc;
if (sector >= part->sector_count)
return -EIO;
addr = part->sector_map[sector];
if (addr != -1) {
rc = mtd_read(part->mbd.mtd, addr, SECTOR_SIZE, &retlen,
(u_char *)buf);
if (!rc && retlen != SECTOR_SIZE)
rc = -EIO;
if (rc) {
printk(KERN_WARNING PREFIX "error reading '%s' at "
"0x%lx\n", part->mbd.mtd->name, addr);
return rc;
}
} else
memset(buf, 0, SECTOR_SIZE);
return 0;
}
static void erase_callback(struct erase_info *erase)
{
struct partition *part;
u16 magic;
int i, rc;
size_t retlen;
part = (struct partition*)erase->priv;
i = (u32)erase->addr / part->block_size;
if (i >= part->total_blocks || part->blocks[i].offset != erase->addr ||
erase->addr > UINT_MAX) {
printk(KERN_ERR PREFIX "erase callback for unknown offset %llx "
"on '%s'\n", (unsigned long long)erase->addr, part->mbd.mtd->name);
return;
}
if (erase->state != MTD_ERASE_DONE) {
printk(KERN_WARNING PREFIX "erase failed at 0x%llx on '%s', "
"state %d\n", (unsigned long long)erase->addr,
part->mbd.mtd->name, erase->state);
part->blocks[i].state = BLOCK_FAILED;
part->blocks[i].free_sectors = 0;
part->blocks[i].used_sectors = 0;
kfree(erase);
return;
}
magic = cpu_to_le16(RFD_MAGIC);
part->blocks[i].state = BLOCK_ERASED;
part->blocks[i].free_sectors = part->data_sectors_per_block;
part->blocks[i].used_sectors = 0;
part->blocks[i].erases++;
rc = mtd_write(part->mbd.mtd, part->blocks[i].offset, sizeof(magic),
&retlen, (u_char *)&magic);
if (!rc && retlen != sizeof(magic))
rc = -EIO;
if (rc) {
printk(KERN_ERR PREFIX "'%s': unable to write RFD "
"header at 0x%lx\n",
part->mbd.mtd->name,
part->blocks[i].offset);
part->blocks[i].state = BLOCK_FAILED;
}
else
part->blocks[i].state = BLOCK_OK;
kfree(erase);
}
static int erase_block(struct partition *part, int block)
{
struct erase_info *erase;
int rc = -ENOMEM;
erase = kmalloc(sizeof(struct erase_info), GFP_KERNEL);
if (!erase)
goto err;
erase->mtd = part->mbd.mtd;
erase->callback = erase_callback;
erase->addr = part->blocks[block].offset;
erase->len = part->block_size;
erase->priv = (u_long)part;
part->blocks[block].state = BLOCK_ERASING;
part->blocks[block].free_sectors = 0;
rc = mtd_erase(part->mbd.mtd, erase);
if (rc) {
printk(KERN_ERR PREFIX "erase of region %llx,%llx on '%s' "
"failed\n", (unsigned long long)erase->addr,
(unsigned long long)erase->len, part->mbd.mtd->name);
kfree(erase);
}
err:
return rc;
}
static int move_block_contents(struct partition *part, int block_no, u_long *old_sector)
{
void *sector_data;
u16 *map;
size_t retlen;
int i, rc = -ENOMEM;
part->is_reclaiming = 1;
sector_data = kmalloc(SECTOR_SIZE, GFP_KERNEL);
if (!sector_data)
goto err3;
map = kmalloc(part->header_size, GFP_KERNEL);
if (!map)
goto err2;
rc = mtd_read(part->mbd.mtd, part->blocks[block_no].offset,
part->header_size, &retlen, (u_char *)map);
if (!rc && retlen != part->header_size)
rc = -EIO;
if (rc) {
printk(KERN_ERR PREFIX "error reading '%s' at "
"0x%lx\n", part->mbd.mtd->name,
part->blocks[block_no].offset);
goto err;
}
for (i=0; i<part->data_sectors_per_block; i++) {
u16 entry = le16_to_cpu(map[HEADER_MAP_OFFSET + i]);
u_long addr;
if (entry == SECTOR_FREE || entry == SECTOR_DELETED)
continue;
if (entry == SECTOR_ZERO)
entry = 0;
/* already warned about and ignored in build_block_map() */
if (entry >= part->sector_count)
continue;
addr = part->blocks[block_no].offset +
(i + part->header_sectors_per_block) * SECTOR_SIZE;
if (*old_sector == addr) {
*old_sector = -1;
if (!part->blocks[block_no].used_sectors--) {
rc = erase_block(part, block_no);
break;
}
continue;
}
rc = mtd_read(part->mbd.mtd, addr, SECTOR_SIZE, &retlen,
sector_data);
if (!rc && retlen != SECTOR_SIZE)
rc = -EIO;
if (rc) {
printk(KERN_ERR PREFIX "'%s': Unable to "
"read sector for relocation\n",
part->mbd.mtd->name);
goto err;
}
rc = rfd_ftl_writesect((struct mtd_blktrans_dev*)part,
entry, sector_data);
if (rc)
goto err;
}
err:
kfree(map);
err2:
kfree(sector_data);
err3:
part->is_reclaiming = 0;
return rc;
}
static int reclaim_block(struct partition *part, u_long *old_sector)
{
int block, best_block, score, old_sector_block;
int rc;
/* we have a race if sync doesn't exist */
mtd_sync(part->mbd.mtd);
score = 0x7fffffff; /* MAX_INT */
best_block = -1;
if (*old_sector != -1)
old_sector_block = *old_sector / part->block_size;
else
old_sector_block = -1;
for (block=0; block<part->total_blocks; block++) {
int this_score;
if (block == part->reserved_block)
continue;
/*
* Postpone reclaiming if there is a free sector as
* more removed sectors is more efficient (have to move
* less).
*/
if (part->blocks[block].free_sectors)
return 0;
this_score = part->blocks[block].used_sectors;
if (block == old_sector_block)
this_score--;
else {
/* no point in moving a full block */
if (part->blocks[block].used_sectors ==
part->data_sectors_per_block)
continue;
}
this_score += part->blocks[block].erases;
if (this_score < score) {
best_block = block;
score = this_score;
}
}
if (best_block == -1)
return -ENOSPC;
part->current_block = -1;
part->reserved_block = best_block;
pr_debug("reclaim_block: reclaiming block #%d with %d used "
"%d free sectors\n", best_block,
part->blocks[best_block].used_sectors,
part->blocks[best_block].free_sectors);
if (part->blocks[best_block].used_sectors)
rc = move_block_contents(part, best_block, old_sector);
else
rc = erase_block(part, best_block);
return rc;
}
/*
* IMPROVE: It would be best to choose the block with the most deleted sectors,
* because if we fill that one up first it'll have the most chance of having
* the least live sectors at reclaim.
*/
static int find_free_block(struct partition *part)
{
int block, stop;
block = part->current_block == -1 ?
jiffies % part->total_blocks : part->current_block;
stop = block;
do {
if (part->blocks[block].free_sectors &&
block != part->reserved_block)
return block;
if (part->blocks[block].state == BLOCK_UNUSED)
erase_block(part, block);
if (++block >= part->total_blocks)
block = 0;
} while (block != stop);
return -1;
}
static int find_writable_block(struct partition *part, u_long *old_sector)
{
int rc, block;
size_t retlen;
block = find_free_block(part);
if (block == -1) {
if (!part->is_reclaiming) {
rc = reclaim_block(part, old_sector);
if (rc)
goto err;
block = find_free_block(part);
}
if (block == -1) {
rc = -ENOSPC;
goto err;
}
}
rc = mtd_read(part->mbd.mtd, part->blocks[block].offset,
part->header_size, &retlen,
(u_char *)part->header_cache);
if (!rc && retlen != part->header_size)
rc = -EIO;
if (rc) {
printk(KERN_ERR PREFIX "'%s': unable to read header at "
"0x%lx\n", part->mbd.mtd->name,
part->blocks[block].offset);
goto err;
}
part->current_block = block;
err:
return rc;
}
static int mark_sector_deleted(struct partition *part, u_long old_addr)
{
int block, offset, rc;
u_long addr;
size_t retlen;
u16 del = cpu_to_le16(SECTOR_DELETED);
block = old_addr / part->block_size;
offset = (old_addr % part->block_size) / SECTOR_SIZE -
part->header_sectors_per_block;
addr = part->blocks[block].offset +
(HEADER_MAP_OFFSET + offset) * sizeof(u16);
rc = mtd_write(part->mbd.mtd, addr, sizeof(del), &retlen,
(u_char *)&del);
if (!rc && retlen != sizeof(del))
rc = -EIO;
if (rc) {
printk(KERN_ERR PREFIX "error writing '%s' at "
"0x%lx\n", part->mbd.mtd->name, addr);
if (rc)
goto err;
}
if (block == part->current_block)
part->header_cache[offset + HEADER_MAP_OFFSET] = del;
part->blocks[block].used_sectors--;
if (!part->blocks[block].used_sectors &&
!part->blocks[block].free_sectors)
rc = erase_block(part, block);
err:
return rc;
}
static int find_free_sector(const struct partition *part, const struct block *block)
{
int i, stop;
i = stop = part->data_sectors_per_block - block->free_sectors;
do {
if (le16_to_cpu(part->header_cache[HEADER_MAP_OFFSET + i])
== SECTOR_FREE)
return i;
if (++i == part->data_sectors_per_block)
i = 0;
}
while(i != stop);
return -1;
}
static int do_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf, ulong *old_addr)
{
struct partition *part = (struct partition*)dev;
struct block *block;
u_long addr;
int i;
int rc;
size_t retlen;
u16 entry;
if (part->current_block == -1 ||
!part->blocks[part->current_block].free_sectors) {
rc = find_writable_block(part, old_addr);
if (rc)
goto err;
}
block = &part->blocks[part->current_block];
i = find_free_sector(part, block);
if (i < 0) {
rc = -ENOSPC;
goto err;
}
addr = (i + part->header_sectors_per_block) * SECTOR_SIZE +
block->offset;
rc = mtd_write(part->mbd.mtd, addr, SECTOR_SIZE, &retlen,
(u_char *)buf);
if (!rc && retlen != SECTOR_SIZE)
rc = -EIO;
if (rc) {
printk(KERN_ERR PREFIX "error writing '%s' at 0x%lx\n",
part->mbd.mtd->name, addr);
if (rc)
goto err;
}
part->sector_map[sector] = addr;
entry = cpu_to_le16(sector == 0 ? SECTOR_ZERO : sector);
part->header_cache[i + HEADER_MAP_OFFSET] = entry;
addr = block->offset + (HEADER_MAP_OFFSET + i) * sizeof(u16);
rc = mtd_write(part->mbd.mtd, addr, sizeof(entry), &retlen,
(u_char *)&entry);
if (!rc && retlen != sizeof(entry))
rc = -EIO;
if (rc) {
printk(KERN_ERR PREFIX "error writing '%s' at 0x%lx\n",
part->mbd.mtd->name, addr);
if (rc)
goto err;
}
block->used_sectors++;
block->free_sectors--;
err:
return rc;
}
static int rfd_ftl_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf)
{
struct partition *part = (struct partition*)dev;
u_long old_addr;
int i;
int rc = 0;
pr_debug("rfd_ftl_writesect(sector=0x%lx)\n", sector);
if (part->reserved_block == -1) {
rc = -EACCES;
goto err;
}
if (sector >= part->sector_count) {
rc = -EIO;
goto err;
}
old_addr = part->sector_map[sector];
for (i=0; i<SECTOR_SIZE; i++) {
if (!buf[i])
continue;
rc = do_writesect(dev, sector, buf, &old_addr);
if (rc)
goto err;
break;
}
if (i == SECTOR_SIZE)
part->sector_map[sector] = -1;
if (old_addr != -1)
rc = mark_sector_deleted(part, old_addr);
err:
return rc;
}
static int rfd_ftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
{
struct partition *part = (struct partition*)dev;
geo->heads = 1;
geo->sectors = SECTORS_PER_TRACK;
geo->cylinders = part->cylinders;
return 0;
}
static void rfd_ftl_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
{
struct partition *part;
if (mtd->type != MTD_NORFLASH || mtd->size > UINT_MAX)
return;
part = kzalloc(sizeof(struct partition), GFP_KERNEL);
if (!part)
return;
part->mbd.mtd = mtd;
if (block_size)
part->block_size = block_size;
else {
if (!mtd->erasesize) {
printk(KERN_WARNING PREFIX "please provide block_size");
goto out;
} else
part->block_size = mtd->erasesize;
}
if (scan_header(part) == 0) {
part->mbd.size = part->sector_count;
part->mbd.tr = tr;
part->mbd.devnum = -1;
if (!(mtd->flags & MTD_WRITEABLE))
part->mbd.readonly = 1;
else if (part->errors) {
printk(KERN_WARNING PREFIX "'%s': errors found, "
"setting read-only\n", mtd->name);
part->mbd.readonly = 1;
}
printk(KERN_INFO PREFIX "name: '%s' type: %d flags %x\n",
mtd->name, mtd->type, mtd->flags);
if (!add_mtd_blktrans_dev((void*)part))
return;
}
out:
kfree(part);
}
static void rfd_ftl_remove_dev(struct mtd_blktrans_dev *dev)
{
struct partition *part = (struct partition*)dev;
int i;
for (i=0; i<part->total_blocks; i++) {
pr_debug("rfd_ftl_remove_dev:'%s': erase unit #%02d: %d erases\n",
part->mbd.mtd->name, i, part->blocks[i].erases);
}
del_mtd_blktrans_dev(dev);
vfree(part->sector_map);
kfree(part->header_cache);
kfree(part->blocks);
}
static struct mtd_blktrans_ops rfd_ftl_tr = {
.name = "rfd",
.major = RFD_FTL_MAJOR,
.part_bits = PART_BITS,
.blksize = SECTOR_SIZE,
.readsect = rfd_ftl_readsect,
.writesect = rfd_ftl_writesect,
.getgeo = rfd_ftl_getgeo,
.add_mtd = rfd_ftl_add_mtd,
.remove_dev = rfd_ftl_remove_dev,
.owner = THIS_MODULE,
};
static int __init init_rfd_ftl(void)
{
return register_mtd_blktrans(&rfd_ftl_tr);
}
static void __exit cleanup_rfd_ftl(void)
{
deregister_mtd_blktrans(&rfd_ftl_tr);
}
module_init(init_rfd_ftl);
module_exit(cleanup_rfd_ftl);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Sean Young <sean@mess.org>");
MODULE_DESCRIPTION("Support code for RFD Flash Translation Layer, "
"used by General Software's Embedded BIOS");