2 * rfd_ftl.c -- resident flash disk (flash translation layer)
4 * Copyright (C) 2005 Sean Young <sean@mess.org>
6 * $Id: rfd_ftl.c,v 1.8 2006/01/15 12:51:44 sean Exp $
8 * This type of flash translation layer (FTL) is used by the Embedded BIOS
9 * by General Software. It is known as the Resident Flash Disk (RFD), see:
11 * http://www.gensw.com/pages/prod/bios/rfd.htm
16 #include <linux/hdreg.h>
17 #include <linux/init.h>
18 #include <linux/mtd/blktrans.h>
19 #include <linux/mtd/mtd.h>
20 #include <linux/vmalloc.h>
21 #include <linux/slab.h>
22 #include <linux/jiffies.h>
24 #include <asm/types.h>
26 #define const_cpu_to_le16 __constant_cpu_to_le16
28 static int block_size
= 0;
29 module_param(block_size
, int, 0);
30 MODULE_PARM_DESC(block_size
, "Block size to use by RFD, defaults to erase unit size");
32 #define PREFIX "rfd_ftl: "
34 /* This major has been assigned by device@lanana.org */
36 #define RFD_FTL_MAJOR 256
39 /* Maximum number of partitions in an FTL region */
42 /* An erase unit should start with this value */
43 #define RFD_MAGIC 0x9193
45 /* the second value is 0xffff or 0xffc8; function unknown */
47 /* the third value is always 0xffff, ignored */
49 /* next is an array of mapping for each corresponding sector */
50 #define HEADER_MAP_OFFSET 3
51 #define SECTOR_DELETED 0x0000
52 #define SECTOR_ZERO 0xfffe
53 #define SECTOR_FREE 0xffff
55 #define SECTOR_SIZE 512
57 #define SECTORS_PER_TRACK 63
74 struct mtd_blktrans_dev mbd
;
76 u_int block_size
; /* size of erase unit */
77 u_int total_blocks
; /* number of erase units */
78 u_int header_sectors_per_block
; /* header sectors in erase unit */
79 u_int data_sectors_per_block
; /* data sectors in erase unit */
80 u_int sector_count
; /* sectors in translated disk */
81 u_int header_size
; /* bytes in header sector */
82 int reserved_block
; /* block next up for reclaim */
83 int current_block
; /* block to write to */
84 u16
*header_cache
; /* cached header */
93 static int rfd_ftl_writesect(struct mtd_blktrans_dev
*dev
, u_long sector
, char *buf
);
95 static int build_block_map(struct partition
*part
, int block_no
)
97 struct block
*block
= &part
->blocks
[block_no
];
100 block
->offset
= part
->block_size
* block_no
;
102 if (le16_to_cpu(part
->header_cache
[0]) != RFD_MAGIC
) {
103 block
->state
= BLOCK_UNUSED
;
107 block
->state
= BLOCK_OK
;
109 for (i
=0; i
<part
->data_sectors_per_block
; i
++) {
112 entry
= le16_to_cpu(part
->header_cache
[HEADER_MAP_OFFSET
+ i
]);
114 if (entry
== SECTOR_DELETED
)
117 if (entry
== SECTOR_FREE
) {
118 block
->free_sectors
++;
122 if (entry
== SECTOR_ZERO
)
125 if (entry
>= part
->sector_count
) {
126 printk(KERN_WARNING PREFIX
127 "'%s': unit #%d: entry %d corrupt, "
128 "sector %d out of range\n",
129 part
->mbd
.mtd
->name
, block_no
, i
, entry
);
133 if (part
->sector_map
[entry
] != -1) {
134 printk(KERN_WARNING PREFIX
135 "'%s': more than one entry for sector %d\n",
136 part
->mbd
.mtd
->name
, entry
);
141 part
->sector_map
[entry
] = block
->offset
+
142 (i
+ part
->header_sectors_per_block
) * SECTOR_SIZE
;
144 block
->used_sectors
++;
147 if (block
->free_sectors
== part
->data_sectors_per_block
)
148 part
->reserved_block
= block_no
;
153 static int scan_header(struct partition
*part
)
155 int sectors_per_block
;
160 sectors_per_block
= part
->block_size
/ SECTOR_SIZE
;
161 part
->total_blocks
= part
->mbd
.mtd
->size
/ part
->block_size
;
163 if (part
->total_blocks
< 2)
166 /* each erase block has three bytes header, followed by the map */
167 part
->header_sectors_per_block
=
168 ((HEADER_MAP_OFFSET
+ sectors_per_block
) *
169 sizeof(u16
) + SECTOR_SIZE
- 1) / SECTOR_SIZE
;
171 part
->data_sectors_per_block
= sectors_per_block
-
172 part
->header_sectors_per_block
;
174 part
->header_size
= (HEADER_MAP_OFFSET
+
175 part
->data_sectors_per_block
) * sizeof(u16
);
177 part
->cylinders
= (part
->data_sectors_per_block
*
178 (part
->total_blocks
- 1) - 1) / SECTORS_PER_TRACK
;
180 part
->sector_count
= part
->cylinders
* SECTORS_PER_TRACK
;
182 part
->current_block
= -1;
183 part
->reserved_block
= -1;
184 part
->is_reclaiming
= 0;
186 part
->header_cache
= kmalloc(part
->header_size
, GFP_KERNEL
);
187 if (!part
->header_cache
)
190 part
->blocks
= kcalloc(part
->total_blocks
, sizeof(struct block
),
195 part
->sector_map
= vmalloc(part
->sector_count
* sizeof(u_long
));
196 if (!part
->sector_map
) {
197 printk(KERN_ERR PREFIX
"'%s': unable to allocate memory for "
198 "sector map", part
->mbd
.mtd
->name
);
202 for (i
=0; i
<part
->sector_count
; i
++)
203 part
->sector_map
[i
] = -1;
205 for (i
=0, blocks_found
=0; i
<part
->total_blocks
; i
++) {
206 rc
= part
->mbd
.mtd
->read(part
->mbd
.mtd
,
207 i
* part
->block_size
, part
->header_size
,
208 &retlen
, (u_char
*)part
->header_cache
);
210 if (!rc
&& retlen
!= part
->header_size
)
216 if (!build_block_map(part
, i
))
220 if (blocks_found
== 0) {
221 printk(KERN_NOTICE PREFIX
"no RFD magic found in '%s'\n",
222 part
->mbd
.mtd
->name
);
227 if (part
->reserved_block
== -1) {
228 printk(KERN_WARNING PREFIX
"'%s': no empty erase unit found\n",
229 part
->mbd
.mtd
->name
);
237 vfree(part
->sector_map
);
238 kfree(part
->header_cache
);
244 static int rfd_ftl_readsect(struct mtd_blktrans_dev
*dev
, u_long sector
, char *buf
)
246 struct partition
*part
= (struct partition
*)dev
;
251 if (sector
>= part
->sector_count
)
254 addr
= part
->sector_map
[sector
];
256 rc
= part
->mbd
.mtd
->read(part
->mbd
.mtd
, addr
, SECTOR_SIZE
,
257 &retlen
, (u_char
*)buf
);
258 if (!rc
&& retlen
!= SECTOR_SIZE
)
262 printk(KERN_WARNING PREFIX
"error reading '%s' at "
263 "0x%lx\n", part
->mbd
.mtd
->name
, addr
);
267 memset(buf
, 0, SECTOR_SIZE
);
272 static void erase_callback(struct erase_info
*erase
)
274 struct partition
*part
;
279 part
= (struct partition
*)erase
->priv
;
281 i
= erase
->addr
/ part
->block_size
;
282 if (i
>= part
->total_blocks
|| part
->blocks
[i
].offset
!= erase
->addr
) {
283 printk(KERN_ERR PREFIX
"erase callback for unknown offset %x "
284 "on '%s'\n", erase
->addr
, part
->mbd
.mtd
->name
);
288 if (erase
->state
!= MTD_ERASE_DONE
) {
289 printk(KERN_WARNING PREFIX
"erase failed at 0x%x on '%s', "
290 "state %d\n", erase
->addr
,
291 part
->mbd
.mtd
->name
, erase
->state
);
293 part
->blocks
[i
].state
= BLOCK_FAILED
;
294 part
->blocks
[i
].free_sectors
= 0;
295 part
->blocks
[i
].used_sectors
= 0;
302 magic
= const_cpu_to_le16(RFD_MAGIC
);
304 part
->blocks
[i
].state
= BLOCK_ERASED
;
305 part
->blocks
[i
].free_sectors
= part
->data_sectors_per_block
;
306 part
->blocks
[i
].used_sectors
= 0;
307 part
->blocks
[i
].erases
++;
309 rc
= part
->mbd
.mtd
->write(part
->mbd
.mtd
,
310 part
->blocks
[i
].offset
, sizeof(magic
), &retlen
,
313 if (!rc
&& retlen
!= sizeof(magic
))
317 printk(KERN_ERR PREFIX
"'%s': unable to write RFD "
320 part
->blocks
[i
].offset
);
321 part
->blocks
[i
].state
= BLOCK_FAILED
;
324 part
->blocks
[i
].state
= BLOCK_OK
;
329 static int erase_block(struct partition
*part
, int block
)
331 struct erase_info
*erase
;
334 erase
= kmalloc(sizeof(struct erase_info
), GFP_KERNEL
);
338 erase
->mtd
= part
->mbd
.mtd
;
339 erase
->callback
= erase_callback
;
340 erase
->addr
= part
->blocks
[block
].offset
;
341 erase
->len
= part
->block_size
;
342 erase
->priv
= (u_long
)part
;
344 part
->blocks
[block
].state
= BLOCK_ERASING
;
345 part
->blocks
[block
].free_sectors
= 0;
347 rc
= part
->mbd
.mtd
->erase(part
->mbd
.mtd
, erase
);
350 printk(KERN_ERR PREFIX
"erase of region %x,%x on '%s' "
351 "failed\n", erase
->addr
, erase
->len
,
352 part
->mbd
.mtd
->name
);
360 static int move_block_contents(struct partition
*part
, int block_no
, u_long
*old_sector
)
367 part
->is_reclaiming
= 1;
369 sector_data
= kmalloc(SECTOR_SIZE
, GFP_KERNEL
);
373 map
= kmalloc(part
->header_size
, GFP_KERNEL
);
377 rc
= part
->mbd
.mtd
->read(part
->mbd
.mtd
,
378 part
->blocks
[block_no
].offset
, part
->header_size
,
379 &retlen
, (u_char
*)map
);
381 if (!rc
&& retlen
!= part
->header_size
)
385 printk(KERN_ERR PREFIX
"error reading '%s' at "
386 "0x%lx\n", part
->mbd
.mtd
->name
,
387 part
->blocks
[block_no
].offset
);
392 for (i
=0; i
<part
->data_sectors_per_block
; i
++) {
393 u16 entry
= le16_to_cpu(map
[HEADER_MAP_OFFSET
+ i
]);
397 if (entry
== SECTOR_FREE
|| entry
== SECTOR_DELETED
)
400 if (entry
== SECTOR_ZERO
)
403 /* already warned about and ignored in build_block_map() */
404 if (entry
>= part
->sector_count
)
407 addr
= part
->blocks
[block_no
].offset
+
408 (i
+ part
->header_sectors_per_block
) * SECTOR_SIZE
;
410 if (*old_sector
== addr
) {
412 if (!part
->blocks
[block_no
].used_sectors
--) {
413 rc
= erase_block(part
, block_no
);
418 rc
= part
->mbd
.mtd
->read(part
->mbd
.mtd
, addr
,
419 SECTOR_SIZE
, &retlen
, sector_data
);
421 if (!rc
&& retlen
!= SECTOR_SIZE
)
425 printk(KERN_ERR PREFIX
"'%s': Unable to "
426 "read sector for relocation\n",
427 part
->mbd
.mtd
->name
);
432 rc
= rfd_ftl_writesect((struct mtd_blktrans_dev
*)part
,
444 part
->is_reclaiming
= 0;
449 static int reclaim_block(struct partition
*part
, u_long
*old_sector
)
451 int block
, best_block
, score
, old_sector_block
;
454 /* we have a race if sync doesn't exist */
455 if (part
->mbd
.mtd
->sync
)
456 part
->mbd
.mtd
->sync(part
->mbd
.mtd
);
458 score
= 0x7fffffff; /* MAX_INT */
460 if (*old_sector
!= -1)
461 old_sector_block
= *old_sector
/ part
->block_size
;
463 old_sector_block
= -1;
465 for (block
=0; block
<part
->total_blocks
; block
++) {
468 if (block
== part
->reserved_block
)
472 * Postpone reclaiming if there is a free sector as
473 * more removed sectors is more efficient (have to move
476 if (part
->blocks
[block
].free_sectors
)
479 this_score
= part
->blocks
[block
].used_sectors
;
481 if (block
== old_sector_block
)
484 /* no point in moving a full block */
485 if (part
->blocks
[block
].used_sectors
==
486 part
->data_sectors_per_block
)
490 this_score
+= part
->blocks
[block
].erases
;
492 if (this_score
< score
) {
498 if (best_block
== -1)
501 part
->current_block
= -1;
502 part
->reserved_block
= best_block
;
504 pr_debug("reclaim_block: reclaiming block #%d with %d used "
505 "%d free sectors\n", best_block
,
506 part
->blocks
[best_block
].used_sectors
,
507 part
->blocks
[best_block
].free_sectors
);
509 if (part
->blocks
[best_block
].used_sectors
)
510 rc
= move_block_contents(part
, best_block
, old_sector
);
512 rc
= erase_block(part
, best_block
);
518 * IMPROVE: It would be best to choose the block with the most deleted sectors,
519 * because if we fill that one up first it'll have the most chance of having
520 * the least live sectors at reclaim.
522 static int find_free_block(struct partition
*part
)
526 block
= part
->current_block
== -1 ?
527 jiffies
% part
->total_blocks
: part
->current_block
;
531 if (part
->blocks
[block
].free_sectors
&&
532 block
!= part
->reserved_block
)
535 if (part
->blocks
[block
].state
== BLOCK_UNUSED
)
536 erase_block(part
, block
);
538 if (++block
>= part
->total_blocks
)
541 } while (block
!= stop
);
546 static int find_writable_block(struct partition
*part
, u_long
*old_sector
)
551 block
= find_free_block(part
);
554 if (!part
->is_reclaiming
) {
555 rc
= reclaim_block(part
, old_sector
);
559 block
= find_free_block(part
);
568 rc
= part
->mbd
.mtd
->read(part
->mbd
.mtd
, part
->blocks
[block
].offset
,
569 part
->header_size
, &retlen
, (u_char
*)part
->header_cache
);
571 if (!rc
&& retlen
!= part
->header_size
)
575 printk(KERN_ERR PREFIX
"'%s': unable to read header at "
576 "0x%lx\n", part
->mbd
.mtd
->name
,
577 part
->blocks
[block
].offset
);
581 part
->current_block
= block
;
587 static int mark_sector_deleted(struct partition
*part
, u_long old_addr
)
589 int block
, offset
, rc
;
592 u16 del
= const_cpu_to_le16(SECTOR_DELETED
);
594 block
= old_addr
/ part
->block_size
;
595 offset
= (old_addr
% part
->block_size
) / SECTOR_SIZE
-
596 part
->header_sectors_per_block
;
598 addr
= part
->blocks
[block
].offset
+
599 (HEADER_MAP_OFFSET
+ offset
) * sizeof(u16
);
600 rc
= part
->mbd
.mtd
->write(part
->mbd
.mtd
, addr
,
601 sizeof(del
), &retlen
, (u_char
*)&del
);
603 if (!rc
&& retlen
!= sizeof(del
))
607 printk(KERN_ERR PREFIX
"error writing '%s' at "
608 "0x%lx\n", part
->mbd
.mtd
->name
, addr
);
612 if (block
== part
->current_block
)
613 part
->header_cache
[offset
+ HEADER_MAP_OFFSET
] = del
;
615 part
->blocks
[block
].used_sectors
--;
617 if (!part
->blocks
[block
].used_sectors
&&
618 !part
->blocks
[block
].free_sectors
)
619 rc
= erase_block(part
, block
);
625 static int find_free_sector(const struct partition
*part
, const struct block
*block
)
629 i
= stop
= part
->data_sectors_per_block
- block
->free_sectors
;
632 if (le16_to_cpu(part
->header_cache
[HEADER_MAP_OFFSET
+ i
])
636 if (++i
== part
->data_sectors_per_block
)
644 static int do_writesect(struct mtd_blktrans_dev
*dev
, u_long sector
, char *buf
, ulong
*old_addr
)
646 struct partition
*part
= (struct partition
*)dev
;
654 if (part
->current_block
== -1 ||
655 !part
->blocks
[part
->current_block
].free_sectors
) {
657 rc
= find_writable_block(part
, old_addr
);
662 block
= &part
->blocks
[part
->current_block
];
664 i
= find_free_sector(part
, block
);
671 addr
= (i
+ part
->header_sectors_per_block
) * SECTOR_SIZE
+
673 rc
= part
->mbd
.mtd
->write(part
->mbd
.mtd
,
674 addr
, SECTOR_SIZE
, &retlen
, (u_char
*)buf
);
676 if (!rc
&& retlen
!= SECTOR_SIZE
)
680 printk(KERN_ERR PREFIX
"error writing '%s' at 0x%lx\n",
681 part
->mbd
.mtd
->name
, addr
);
686 part
->sector_map
[sector
] = addr
;
688 entry
= cpu_to_le16(sector
== 0 ? SECTOR_ZERO
: sector
);
690 part
->header_cache
[i
+ HEADER_MAP_OFFSET
] = entry
;
692 addr
= block
->offset
+ (HEADER_MAP_OFFSET
+ i
) * sizeof(u16
);
693 rc
= part
->mbd
.mtd
->write(part
->mbd
.mtd
, addr
,
694 sizeof(entry
), &retlen
, (u_char
*)&entry
);
696 if (!rc
&& retlen
!= sizeof(entry
))
700 printk(KERN_ERR PREFIX
"error writing '%s' at 0x%lx\n",
701 part
->mbd
.mtd
->name
, addr
);
705 block
->used_sectors
++;
706 block
->free_sectors
--;
712 static int rfd_ftl_writesect(struct mtd_blktrans_dev
*dev
, u_long sector
, char *buf
)
714 struct partition
*part
= (struct partition
*)dev
;
719 pr_debug("rfd_ftl_writesect(sector=0x%lx)\n", sector
);
721 if (part
->reserved_block
== -1) {
726 if (sector
>= part
->sector_count
) {
731 old_addr
= part
->sector_map
[sector
];
733 for (i
=0; i
<SECTOR_SIZE
; i
++) {
737 rc
= do_writesect(dev
, sector
, buf
, &old_addr
);
743 if (i
== SECTOR_SIZE
)
744 part
->sector_map
[sector
] = -1;
747 rc
= mark_sector_deleted(part
, old_addr
);
753 static int rfd_ftl_getgeo(struct mtd_blktrans_dev
*dev
, struct hd_geometry
*geo
)
755 struct partition
*part
= (struct partition
*)dev
;
758 geo
->sectors
= SECTORS_PER_TRACK
;
759 geo
->cylinders
= part
->cylinders
;
764 static void rfd_ftl_add_mtd(struct mtd_blktrans_ops
*tr
, struct mtd_info
*mtd
)
766 struct partition
*part
;
768 if (mtd
->type
!= MTD_NORFLASH
)
771 part
= kzalloc(sizeof(struct partition
), GFP_KERNEL
);
778 part
->block_size
= block_size
;
780 if (!mtd
->erasesize
) {
781 printk(KERN_WARNING PREFIX
"please provide block_size");
784 part
->block_size
= mtd
->erasesize
;
787 if (scan_header(part
) == 0) {
788 part
->mbd
.size
= part
->sector_count
;
790 part
->mbd
.devnum
= -1;
791 if (!(mtd
->flags
& MTD_WRITEABLE
))
792 part
->mbd
.readonly
= 1;
793 else if (part
->errors
) {
794 printk(KERN_WARNING PREFIX
"'%s': errors found, "
795 "setting read-only\n", mtd
->name
);
796 part
->mbd
.readonly
= 1;
799 printk(KERN_INFO PREFIX
"name: '%s' type: %d flags %x\n",
800 mtd
->name
, mtd
->type
, mtd
->flags
);
802 if (!add_mtd_blktrans_dev((void*)part
))
809 static void rfd_ftl_remove_dev(struct mtd_blktrans_dev
*dev
)
811 struct partition
*part
= (struct partition
*)dev
;
814 for (i
=0; i
<part
->total_blocks
; i
++) {
815 pr_debug("rfd_ftl_remove_dev:'%s': erase unit #%02d: %d erases\n",
816 part
->mbd
.mtd
->name
, i
, part
->blocks
[i
].erases
);
819 del_mtd_blktrans_dev(dev
);
820 vfree(part
->sector_map
);
821 kfree(part
->header_cache
);
826 struct mtd_blktrans_ops rfd_ftl_tr
= {
828 .major
= RFD_FTL_MAJOR
,
829 .part_bits
= PART_BITS
,
830 .blksize
= SECTOR_SIZE
,
832 .readsect
= rfd_ftl_readsect
,
833 .writesect
= rfd_ftl_writesect
,
834 .getgeo
= rfd_ftl_getgeo
,
835 .add_mtd
= rfd_ftl_add_mtd
,
836 .remove_dev
= rfd_ftl_remove_dev
,
837 .owner
= THIS_MODULE
,
840 static int __init
init_rfd_ftl(void)
842 return register_mtd_blktrans(&rfd_ftl_tr
);
845 static void __exit
cleanup_rfd_ftl(void)
847 deregister_mtd_blktrans(&rfd_ftl_tr
);
850 module_init(init_rfd_ftl
);
851 module_exit(cleanup_rfd_ftl
);
853 MODULE_LICENSE("GPL");
854 MODULE_AUTHOR("Sean Young <sean@mess.org>");
855 MODULE_DESCRIPTION("Support code for RFD Flash Translation Layer, "
856 "used by General Software's Embedded BIOS");