2 * rfd_ftl.c -- resident flash disk (flash translation layer)
4 * Copyright © 2005 Sean Young <sean@mess.org>
6 * This type of flash translation layer (FTL) is used by the Embedded BIOS
7 * by General Software. It is known as the Resident Flash Disk (RFD), see:
9 * http://www.gensw.com/pages/prod/bios/rfd.htm
14 #include <linux/hdreg.h>
15 #include <linux/init.h>
16 #include <linux/mtd/blktrans.h>
17 #include <linux/mtd/mtd.h>
18 #include <linux/vmalloc.h>
19 #include <linux/slab.h>
20 #include <linux/jiffies.h>
21 #include <linux/module.h>
23 #include <asm/types.h>
25 static int block_size
= 0;
26 module_param(block_size
, int, 0);
27 MODULE_PARM_DESC(block_size
, "Block size to use by RFD, defaults to erase unit size");
29 #define PREFIX "rfd_ftl: "
31 /* This major has been assigned by device@lanana.org */
33 #define RFD_FTL_MAJOR 256
36 /* Maximum number of partitions in an FTL region */
39 /* An erase unit should start with this value */
40 #define RFD_MAGIC 0x9193
42 /* the second value is 0xffff or 0xffc8; function unknown */
44 /* the third value is always 0xffff, ignored */
46 /* next is an array of mapping for each corresponding sector */
47 #define HEADER_MAP_OFFSET 3
48 #define SECTOR_DELETED 0x0000
49 #define SECTOR_ZERO 0xfffe
50 #define SECTOR_FREE 0xffff
52 #define SECTOR_SIZE 512
54 #define SECTORS_PER_TRACK 63
71 struct mtd_blktrans_dev mbd
;
73 u_int block_size
; /* size of erase unit */
74 u_int total_blocks
; /* number of erase units */
75 u_int header_sectors_per_block
; /* header sectors in erase unit */
76 u_int data_sectors_per_block
; /* data sectors in erase unit */
77 u_int sector_count
; /* sectors in translated disk */
78 u_int header_size
; /* bytes in header sector */
79 int reserved_block
; /* block next up for reclaim */
80 int current_block
; /* block to write to */
81 u16
*header_cache
; /* cached header */
90 static int rfd_ftl_writesect(struct mtd_blktrans_dev
*dev
, u_long sector
, char *buf
);
92 static int build_block_map(struct partition
*part
, int block_no
)
94 struct block
*block
= &part
->blocks
[block_no
];
97 block
->offset
= part
->block_size
* block_no
;
99 if (le16_to_cpu(part
->header_cache
[0]) != RFD_MAGIC
) {
100 block
->state
= BLOCK_UNUSED
;
104 block
->state
= BLOCK_OK
;
106 for (i
=0; i
<part
->data_sectors_per_block
; i
++) {
109 entry
= le16_to_cpu(part
->header_cache
[HEADER_MAP_OFFSET
+ i
]);
111 if (entry
== SECTOR_DELETED
)
114 if (entry
== SECTOR_FREE
) {
115 block
->free_sectors
++;
119 if (entry
== SECTOR_ZERO
)
122 if (entry
>= part
->sector_count
) {
123 printk(KERN_WARNING PREFIX
124 "'%s': unit #%d: entry %d corrupt, "
125 "sector %d out of range\n",
126 part
->mbd
.mtd
->name
, block_no
, i
, entry
);
130 if (part
->sector_map
[entry
] != -1) {
131 printk(KERN_WARNING PREFIX
132 "'%s': more than one entry for sector %d\n",
133 part
->mbd
.mtd
->name
, entry
);
138 part
->sector_map
[entry
] = block
->offset
+
139 (i
+ part
->header_sectors_per_block
) * SECTOR_SIZE
;
141 block
->used_sectors
++;
144 if (block
->free_sectors
== part
->data_sectors_per_block
)
145 part
->reserved_block
= block_no
;
150 static int scan_header(struct partition
*part
)
152 int sectors_per_block
;
157 sectors_per_block
= part
->block_size
/ SECTOR_SIZE
;
158 part
->total_blocks
= (u32
)part
->mbd
.mtd
->size
/ part
->block_size
;
160 if (part
->total_blocks
< 2)
163 /* each erase block has three bytes header, followed by the map */
164 part
->header_sectors_per_block
=
165 ((HEADER_MAP_OFFSET
+ sectors_per_block
) *
166 sizeof(u16
) + SECTOR_SIZE
- 1) / SECTOR_SIZE
;
168 part
->data_sectors_per_block
= sectors_per_block
-
169 part
->header_sectors_per_block
;
171 part
->header_size
= (HEADER_MAP_OFFSET
+
172 part
->data_sectors_per_block
) * sizeof(u16
);
174 part
->cylinders
= (part
->data_sectors_per_block
*
175 (part
->total_blocks
- 1) - 1) / SECTORS_PER_TRACK
;
177 part
->sector_count
= part
->cylinders
* SECTORS_PER_TRACK
;
179 part
->current_block
= -1;
180 part
->reserved_block
= -1;
181 part
->is_reclaiming
= 0;
183 part
->header_cache
= kmalloc(part
->header_size
, GFP_KERNEL
);
184 if (!part
->header_cache
)
187 part
->blocks
= kcalloc(part
->total_blocks
, sizeof(struct block
),
192 part
->sector_map
= vmalloc(part
->sector_count
* sizeof(u_long
));
193 if (!part
->sector_map
) {
194 printk(KERN_ERR PREFIX
"'%s': unable to allocate memory for "
195 "sector map", part
->mbd
.mtd
->name
);
199 for (i
=0; i
<part
->sector_count
; i
++)
200 part
->sector_map
[i
] = -1;
202 for (i
=0, blocks_found
=0; i
<part
->total_blocks
; i
++) {
203 rc
= mtd_read(part
->mbd
.mtd
, i
* part
->block_size
,
204 part
->header_size
, &retlen
,
205 (u_char
*)part
->header_cache
);
207 if (!rc
&& retlen
!= part
->header_size
)
213 if (!build_block_map(part
, i
))
217 if (blocks_found
== 0) {
218 printk(KERN_NOTICE PREFIX
"no RFD magic found in '%s'\n",
219 part
->mbd
.mtd
->name
);
224 if (part
->reserved_block
== -1) {
225 printk(KERN_WARNING PREFIX
"'%s': no empty erase unit found\n",
226 part
->mbd
.mtd
->name
);
234 vfree(part
->sector_map
);
235 kfree(part
->header_cache
);
241 static int rfd_ftl_readsect(struct mtd_blktrans_dev
*dev
, u_long sector
, char *buf
)
243 struct partition
*part
= (struct partition
*)dev
;
248 if (sector
>= part
->sector_count
)
251 addr
= part
->sector_map
[sector
];
253 rc
= mtd_read(part
->mbd
.mtd
, addr
, SECTOR_SIZE
, &retlen
,
255 if (!rc
&& retlen
!= SECTOR_SIZE
)
259 printk(KERN_WARNING PREFIX
"error reading '%s' at "
260 "0x%lx\n", part
->mbd
.mtd
->name
, addr
);
264 memset(buf
, 0, SECTOR_SIZE
);
269 static void erase_callback(struct erase_info
*erase
)
271 struct partition
*part
;
276 part
= (struct partition
*)erase
->priv
;
278 i
= (u32
)erase
->addr
/ part
->block_size
;
279 if (i
>= part
->total_blocks
|| part
->blocks
[i
].offset
!= erase
->addr
||
280 erase
->addr
> UINT_MAX
) {
281 printk(KERN_ERR PREFIX
"erase callback for unknown offset %llx "
282 "on '%s'\n", (unsigned long long)erase
->addr
, part
->mbd
.mtd
->name
);
286 if (erase
->state
!= MTD_ERASE_DONE
) {
287 printk(KERN_WARNING PREFIX
"erase failed at 0x%llx on '%s', "
288 "state %d\n", (unsigned long long)erase
->addr
,
289 part
->mbd
.mtd
->name
, erase
->state
);
291 part
->blocks
[i
].state
= BLOCK_FAILED
;
292 part
->blocks
[i
].free_sectors
= 0;
293 part
->blocks
[i
].used_sectors
= 0;
300 magic
= cpu_to_le16(RFD_MAGIC
);
302 part
->blocks
[i
].state
= BLOCK_ERASED
;
303 part
->blocks
[i
].free_sectors
= part
->data_sectors_per_block
;
304 part
->blocks
[i
].used_sectors
= 0;
305 part
->blocks
[i
].erases
++;
307 rc
= mtd_write(part
->mbd
.mtd
, part
->blocks
[i
].offset
, sizeof(magic
),
308 &retlen
, (u_char
*)&magic
);
310 if (!rc
&& retlen
!= sizeof(magic
))
314 printk(KERN_ERR PREFIX
"'%s': unable to write RFD "
317 part
->blocks
[i
].offset
);
318 part
->blocks
[i
].state
= BLOCK_FAILED
;
321 part
->blocks
[i
].state
= BLOCK_OK
;
326 static int erase_block(struct partition
*part
, int block
)
328 struct erase_info
*erase
;
331 erase
= kmalloc(sizeof(struct erase_info
), GFP_KERNEL
);
335 erase
->mtd
= part
->mbd
.mtd
;
336 erase
->callback
= erase_callback
;
337 erase
->addr
= part
->blocks
[block
].offset
;
338 erase
->len
= part
->block_size
;
339 erase
->priv
= (u_long
)part
;
341 part
->blocks
[block
].state
= BLOCK_ERASING
;
342 part
->blocks
[block
].free_sectors
= 0;
344 rc
= mtd_erase(part
->mbd
.mtd
, erase
);
347 printk(KERN_ERR PREFIX
"erase of region %llx,%llx on '%s' "
348 "failed\n", (unsigned long long)erase
->addr
,
349 (unsigned long long)erase
->len
, part
->mbd
.mtd
->name
);
357 static int move_block_contents(struct partition
*part
, int block_no
, u_long
*old_sector
)
364 part
->is_reclaiming
= 1;
366 sector_data
= kmalloc(SECTOR_SIZE
, GFP_KERNEL
);
370 map
= kmalloc(part
->header_size
, GFP_KERNEL
);
374 rc
= mtd_read(part
->mbd
.mtd
, part
->blocks
[block_no
].offset
,
375 part
->header_size
, &retlen
, (u_char
*)map
);
377 if (!rc
&& retlen
!= part
->header_size
)
381 printk(KERN_ERR PREFIX
"error reading '%s' at "
382 "0x%lx\n", part
->mbd
.mtd
->name
,
383 part
->blocks
[block_no
].offset
);
388 for (i
=0; i
<part
->data_sectors_per_block
; i
++) {
389 u16 entry
= le16_to_cpu(map
[HEADER_MAP_OFFSET
+ i
]);
393 if (entry
== SECTOR_FREE
|| entry
== SECTOR_DELETED
)
396 if (entry
== SECTOR_ZERO
)
399 /* already warned about and ignored in build_block_map() */
400 if (entry
>= part
->sector_count
)
403 addr
= part
->blocks
[block_no
].offset
+
404 (i
+ part
->header_sectors_per_block
) * SECTOR_SIZE
;
406 if (*old_sector
== addr
) {
408 if (!part
->blocks
[block_no
].used_sectors
--) {
409 rc
= erase_block(part
, block_no
);
414 rc
= mtd_read(part
->mbd
.mtd
, addr
, SECTOR_SIZE
, &retlen
,
417 if (!rc
&& retlen
!= SECTOR_SIZE
)
421 printk(KERN_ERR PREFIX
"'%s': Unable to "
422 "read sector for relocation\n",
423 part
->mbd
.mtd
->name
);
428 rc
= rfd_ftl_writesect((struct mtd_blktrans_dev
*)part
,
440 part
->is_reclaiming
= 0;
445 static int reclaim_block(struct partition
*part
, u_long
*old_sector
)
447 int block
, best_block
, score
, old_sector_block
;
450 /* we have a race if sync doesn't exist */
451 mtd_sync(part
->mbd
.mtd
);
453 score
= 0x7fffffff; /* MAX_INT */
455 if (*old_sector
!= -1)
456 old_sector_block
= *old_sector
/ part
->block_size
;
458 old_sector_block
= -1;
460 for (block
=0; block
<part
->total_blocks
; block
++) {
463 if (block
== part
->reserved_block
)
467 * Postpone reclaiming if there is a free sector as
468 * more removed sectors is more efficient (have to move
471 if (part
->blocks
[block
].free_sectors
)
474 this_score
= part
->blocks
[block
].used_sectors
;
476 if (block
== old_sector_block
)
479 /* no point in moving a full block */
480 if (part
->blocks
[block
].used_sectors
==
481 part
->data_sectors_per_block
)
485 this_score
+= part
->blocks
[block
].erases
;
487 if (this_score
< score
) {
493 if (best_block
== -1)
496 part
->current_block
= -1;
497 part
->reserved_block
= best_block
;
499 pr_debug("reclaim_block: reclaiming block #%d with %d used "
500 "%d free sectors\n", best_block
,
501 part
->blocks
[best_block
].used_sectors
,
502 part
->blocks
[best_block
].free_sectors
);
504 if (part
->blocks
[best_block
].used_sectors
)
505 rc
= move_block_contents(part
, best_block
, old_sector
);
507 rc
= erase_block(part
, best_block
);
513 * IMPROVE: It would be best to choose the block with the most deleted sectors,
514 * because if we fill that one up first it'll have the most chance of having
515 * the least live sectors at reclaim.
517 static int find_free_block(struct partition
*part
)
521 block
= part
->current_block
== -1 ?
522 jiffies
% part
->total_blocks
: part
->current_block
;
526 if (part
->blocks
[block
].free_sectors
&&
527 block
!= part
->reserved_block
)
530 if (part
->blocks
[block
].state
== BLOCK_UNUSED
)
531 erase_block(part
, block
);
533 if (++block
>= part
->total_blocks
)
536 } while (block
!= stop
);
541 static int find_writable_block(struct partition
*part
, u_long
*old_sector
)
546 block
= find_free_block(part
);
549 if (!part
->is_reclaiming
) {
550 rc
= reclaim_block(part
, old_sector
);
554 block
= find_free_block(part
);
563 rc
= mtd_read(part
->mbd
.mtd
, part
->blocks
[block
].offset
,
564 part
->header_size
, &retlen
,
565 (u_char
*)part
->header_cache
);
567 if (!rc
&& retlen
!= part
->header_size
)
571 printk(KERN_ERR PREFIX
"'%s': unable to read header at "
572 "0x%lx\n", part
->mbd
.mtd
->name
,
573 part
->blocks
[block
].offset
);
577 part
->current_block
= block
;
583 static int mark_sector_deleted(struct partition
*part
, u_long old_addr
)
585 int block
, offset
, rc
;
588 u16 del
= cpu_to_le16(SECTOR_DELETED
);
590 block
= old_addr
/ part
->block_size
;
591 offset
= (old_addr
% part
->block_size
) / SECTOR_SIZE
-
592 part
->header_sectors_per_block
;
594 addr
= part
->blocks
[block
].offset
+
595 (HEADER_MAP_OFFSET
+ offset
) * sizeof(u16
);
596 rc
= mtd_write(part
->mbd
.mtd
, addr
, sizeof(del
), &retlen
,
599 if (!rc
&& retlen
!= sizeof(del
))
603 printk(KERN_ERR PREFIX
"error writing '%s' at "
604 "0x%lx\n", part
->mbd
.mtd
->name
, addr
);
607 if (block
== part
->current_block
)
608 part
->header_cache
[offset
+ HEADER_MAP_OFFSET
] = del
;
610 part
->blocks
[block
].used_sectors
--;
612 if (!part
->blocks
[block
].used_sectors
&&
613 !part
->blocks
[block
].free_sectors
)
614 rc
= erase_block(part
, block
);
620 static int find_free_sector(const struct partition
*part
, const struct block
*block
)
624 i
= stop
= part
->data_sectors_per_block
- block
->free_sectors
;
627 if (le16_to_cpu(part
->header_cache
[HEADER_MAP_OFFSET
+ i
])
631 if (++i
== part
->data_sectors_per_block
)
639 static int do_writesect(struct mtd_blktrans_dev
*dev
, u_long sector
, char *buf
, ulong
*old_addr
)
641 struct partition
*part
= (struct partition
*)dev
;
649 if (part
->current_block
== -1 ||
650 !part
->blocks
[part
->current_block
].free_sectors
) {
652 rc
= find_writable_block(part
, old_addr
);
657 block
= &part
->blocks
[part
->current_block
];
659 i
= find_free_sector(part
, block
);
666 addr
= (i
+ part
->header_sectors_per_block
) * SECTOR_SIZE
+
668 rc
= mtd_write(part
->mbd
.mtd
, addr
, SECTOR_SIZE
, &retlen
,
671 if (!rc
&& retlen
!= SECTOR_SIZE
)
675 printk(KERN_ERR PREFIX
"error writing '%s' at 0x%lx\n",
676 part
->mbd
.mtd
->name
, addr
);
680 part
->sector_map
[sector
] = addr
;
682 entry
= cpu_to_le16(sector
== 0 ? SECTOR_ZERO
: sector
);
684 part
->header_cache
[i
+ HEADER_MAP_OFFSET
] = entry
;
686 addr
= block
->offset
+ (HEADER_MAP_OFFSET
+ i
) * sizeof(u16
);
687 rc
= mtd_write(part
->mbd
.mtd
, addr
, sizeof(entry
), &retlen
,
690 if (!rc
&& retlen
!= sizeof(entry
))
694 printk(KERN_ERR PREFIX
"error writing '%s' at 0x%lx\n",
695 part
->mbd
.mtd
->name
, addr
);
698 block
->used_sectors
++;
699 block
->free_sectors
--;
705 static int rfd_ftl_writesect(struct mtd_blktrans_dev
*dev
, u_long sector
, char *buf
)
707 struct partition
*part
= (struct partition
*)dev
;
712 pr_debug("rfd_ftl_writesect(sector=0x%lx)\n", sector
);
714 if (part
->reserved_block
== -1) {
719 if (sector
>= part
->sector_count
) {
724 old_addr
= part
->sector_map
[sector
];
726 for (i
=0; i
<SECTOR_SIZE
; i
++) {
730 rc
= do_writesect(dev
, sector
, buf
, &old_addr
);
736 if (i
== SECTOR_SIZE
)
737 part
->sector_map
[sector
] = -1;
740 rc
= mark_sector_deleted(part
, old_addr
);
746 static int rfd_ftl_getgeo(struct mtd_blktrans_dev
*dev
, struct hd_geometry
*geo
)
748 struct partition
*part
= (struct partition
*)dev
;
751 geo
->sectors
= SECTORS_PER_TRACK
;
752 geo
->cylinders
= part
->cylinders
;
757 static void rfd_ftl_add_mtd(struct mtd_blktrans_ops
*tr
, struct mtd_info
*mtd
)
759 struct partition
*part
;
761 if (mtd
->type
!= MTD_NORFLASH
|| mtd
->size
> UINT_MAX
)
764 part
= kzalloc(sizeof(struct partition
), GFP_KERNEL
);
771 part
->block_size
= block_size
;
773 if (!mtd
->erasesize
) {
774 printk(KERN_WARNING PREFIX
"please provide block_size");
777 part
->block_size
= mtd
->erasesize
;
780 if (scan_header(part
) == 0) {
781 part
->mbd
.size
= part
->sector_count
;
783 part
->mbd
.devnum
= -1;
784 if (!(mtd
->flags
& MTD_WRITEABLE
))
785 part
->mbd
.readonly
= 1;
786 else if (part
->errors
) {
787 printk(KERN_WARNING PREFIX
"'%s': errors found, "
788 "setting read-only\n", mtd
->name
);
789 part
->mbd
.readonly
= 1;
792 printk(KERN_INFO PREFIX
"name: '%s' type: %d flags %x\n",
793 mtd
->name
, mtd
->type
, mtd
->flags
);
795 if (!add_mtd_blktrans_dev((void*)part
))
802 static void rfd_ftl_remove_dev(struct mtd_blktrans_dev
*dev
)
804 struct partition
*part
= (struct partition
*)dev
;
807 for (i
=0; i
<part
->total_blocks
; i
++) {
808 pr_debug("rfd_ftl_remove_dev:'%s': erase unit #%02d: %d erases\n",
809 part
->mbd
.mtd
->name
, i
, part
->blocks
[i
].erases
);
812 del_mtd_blktrans_dev(dev
);
813 vfree(part
->sector_map
);
814 kfree(part
->header_cache
);
818 static struct mtd_blktrans_ops rfd_ftl_tr
= {
820 .major
= RFD_FTL_MAJOR
,
821 .part_bits
= PART_BITS
,
822 .blksize
= SECTOR_SIZE
,
824 .readsect
= rfd_ftl_readsect
,
825 .writesect
= rfd_ftl_writesect
,
826 .getgeo
= rfd_ftl_getgeo
,
827 .add_mtd
= rfd_ftl_add_mtd
,
828 .remove_dev
= rfd_ftl_remove_dev
,
829 .owner
= THIS_MODULE
,
832 static int __init
init_rfd_ftl(void)
834 return register_mtd_blktrans(&rfd_ftl_tr
);
837 static void __exit
cleanup_rfd_ftl(void)
839 deregister_mtd_blktrans(&rfd_ftl_tr
);
842 module_init(init_rfd_ftl
);
843 module_exit(cleanup_rfd_ftl
);
845 MODULE_LICENSE("GPL");
846 MODULE_AUTHOR("Sean Young <sean@mess.org>");
847 MODULE_DESCRIPTION("Support code for RFD Flash Translation Layer, "
848 "used by General Software's Embedded BIOS");