1 // SPDX-License-Identifier: GPL-2.0-only
3 * rfd_ftl.c -- resident flash disk (flash translation layer)
5 * Copyright © 2005 Sean Young <sean@mess.org>
7 * This type of flash translation layer (FTL) is used by the Embedded BIOS
8 * by General Software. It is known as the Resident Flash Disk (RFD), see:
10 * http://www.gensw.com/pages/prod/bios/rfd.htm
15 #include <linux/hdreg.h>
16 #include <linux/init.h>
17 #include <linux/mtd/blktrans.h>
18 #include <linux/mtd/mtd.h>
19 #include <linux/vmalloc.h>
20 #include <linux/slab.h>
21 #include <linux/jiffies.h>
22 #include <linux/module.h>
24 #include <asm/types.h>
26 static int block_size
= 0;
27 module_param(block_size
, int, 0);
28 MODULE_PARM_DESC(block_size
, "Block size to use by RFD, defaults to erase unit size");
30 #define PREFIX "rfd_ftl: "
32 /* This major has been assigned by device@lanana.org */
34 #define RFD_FTL_MAJOR 256
37 /* Maximum number of partitions in an FTL region */
40 /* An erase unit should start with this value */
41 #define RFD_MAGIC 0x9193
43 /* the second value is 0xffff or 0xffc8; function unknown */
45 /* the third value is always 0xffff, ignored */
47 /* next is an array of mapping for each corresponding sector */
48 #define HEADER_MAP_OFFSET 3
49 #define SECTOR_DELETED 0x0000
50 #define SECTOR_ZERO 0xfffe
51 #define SECTOR_FREE 0xffff
53 #define SECTOR_SIZE 512
55 #define SECTORS_PER_TRACK 63
72 struct mtd_blktrans_dev mbd
;
74 u_int block_size
; /* size of erase unit */
75 u_int total_blocks
; /* number of erase units */
76 u_int header_sectors_per_block
; /* header sectors in erase unit */
77 u_int data_sectors_per_block
; /* data sectors in erase unit */
78 u_int sector_count
; /* sectors in translated disk */
79 u_int header_size
; /* bytes in header sector */
80 int reserved_block
; /* block next up for reclaim */
81 int current_block
; /* block to write to */
82 u16
*header_cache
; /* cached header */
91 static int rfd_ftl_writesect(struct mtd_blktrans_dev
*dev
, u_long sector
, char *buf
);
93 static int build_block_map(struct partition
*part
, int block_no
)
95 struct block
*block
= &part
->blocks
[block_no
];
98 block
->offset
= part
->block_size
* block_no
;
100 if (le16_to_cpu(part
->header_cache
[0]) != RFD_MAGIC
) {
101 block
->state
= BLOCK_UNUSED
;
105 block
->state
= BLOCK_OK
;
107 for (i
=0; i
<part
->data_sectors_per_block
; i
++) {
110 entry
= le16_to_cpu(part
->header_cache
[HEADER_MAP_OFFSET
+ i
]);
112 if (entry
== SECTOR_DELETED
)
115 if (entry
== SECTOR_FREE
) {
116 block
->free_sectors
++;
120 if (entry
== SECTOR_ZERO
)
123 if (entry
>= part
->sector_count
) {
124 printk(KERN_WARNING PREFIX
125 "'%s': unit #%d: entry %d corrupt, "
126 "sector %d out of range\n",
127 part
->mbd
.mtd
->name
, block_no
, i
, entry
);
131 if (part
->sector_map
[entry
] != -1) {
132 printk(KERN_WARNING PREFIX
133 "'%s': more than one entry for sector %d\n",
134 part
->mbd
.mtd
->name
, entry
);
139 part
->sector_map
[entry
] = block
->offset
+
140 (i
+ part
->header_sectors_per_block
) * SECTOR_SIZE
;
142 block
->used_sectors
++;
145 if (block
->free_sectors
== part
->data_sectors_per_block
)
146 part
->reserved_block
= block_no
;
151 static int scan_header(struct partition
*part
)
153 int sectors_per_block
;
158 sectors_per_block
= part
->block_size
/ SECTOR_SIZE
;
159 part
->total_blocks
= (u32
)part
->mbd
.mtd
->size
/ part
->block_size
;
161 if (part
->total_blocks
< 2)
164 /* each erase block has three bytes header, followed by the map */
165 part
->header_sectors_per_block
=
166 ((HEADER_MAP_OFFSET
+ sectors_per_block
) *
167 sizeof(u16
) + SECTOR_SIZE
- 1) / SECTOR_SIZE
;
169 part
->data_sectors_per_block
= sectors_per_block
-
170 part
->header_sectors_per_block
;
172 part
->header_size
= (HEADER_MAP_OFFSET
+
173 part
->data_sectors_per_block
) * sizeof(u16
);
175 part
->cylinders
= (part
->data_sectors_per_block
*
176 (part
->total_blocks
- 1) - 1) / SECTORS_PER_TRACK
;
178 part
->sector_count
= part
->cylinders
* SECTORS_PER_TRACK
;
180 part
->current_block
= -1;
181 part
->reserved_block
= -1;
182 part
->is_reclaiming
= 0;
184 part
->header_cache
= kmalloc(part
->header_size
, GFP_KERNEL
);
185 if (!part
->header_cache
)
188 part
->blocks
= kcalloc(part
->total_blocks
, sizeof(struct block
),
193 part
->sector_map
= vmalloc(array_size(sizeof(u_long
),
194 part
->sector_count
));
195 if (!part
->sector_map
) {
196 printk(KERN_ERR PREFIX
"'%s': unable to allocate memory for "
197 "sector map", part
->mbd
.mtd
->name
);
201 for (i
=0; i
<part
->sector_count
; i
++)
202 part
->sector_map
[i
] = -1;
204 for (i
=0, blocks_found
=0; i
<part
->total_blocks
; i
++) {
205 rc
= mtd_read(part
->mbd
.mtd
, i
* part
->block_size
,
206 part
->header_size
, &retlen
,
207 (u_char
*)part
->header_cache
);
209 if (!rc
&& retlen
!= part
->header_size
)
215 if (!build_block_map(part
, i
))
219 if (blocks_found
== 0) {
220 printk(KERN_NOTICE PREFIX
"no RFD magic found in '%s'\n",
221 part
->mbd
.mtd
->name
);
226 if (part
->reserved_block
== -1) {
227 printk(KERN_WARNING PREFIX
"'%s': no empty erase unit found\n",
228 part
->mbd
.mtd
->name
);
236 vfree(part
->sector_map
);
237 kfree(part
->header_cache
);
243 static int rfd_ftl_readsect(struct mtd_blktrans_dev
*dev
, u_long sector
, char *buf
)
245 struct partition
*part
= (struct partition
*)dev
;
250 if (sector
>= part
->sector_count
)
253 addr
= part
->sector_map
[sector
];
255 rc
= mtd_read(part
->mbd
.mtd
, addr
, SECTOR_SIZE
, &retlen
,
257 if (!rc
&& retlen
!= SECTOR_SIZE
)
261 printk(KERN_WARNING PREFIX
"error reading '%s' at "
262 "0x%lx\n", part
->mbd
.mtd
->name
, addr
);
266 memset(buf
, 0, SECTOR_SIZE
);
271 static int erase_block(struct partition
*part
, int block
)
273 struct erase_info
*erase
;
276 erase
= kmalloc(sizeof(struct erase_info
), GFP_KERNEL
);
280 erase
->addr
= part
->blocks
[block
].offset
;
281 erase
->len
= part
->block_size
;
283 part
->blocks
[block
].state
= BLOCK_ERASING
;
284 part
->blocks
[block
].free_sectors
= 0;
286 rc
= mtd_erase(part
->mbd
.mtd
, erase
);
288 printk(KERN_ERR PREFIX
"erase of region %llx,%llx on '%s' "
289 "failed\n", (unsigned long long)erase
->addr
,
290 (unsigned long long)erase
->len
, part
->mbd
.mtd
->name
);
291 part
->blocks
[block
].state
= BLOCK_FAILED
;
292 part
->blocks
[block
].free_sectors
= 0;
293 part
->blocks
[block
].used_sectors
= 0;
295 u16 magic
= cpu_to_le16(RFD_MAGIC
);
298 part
->blocks
[block
].state
= BLOCK_ERASED
;
299 part
->blocks
[block
].free_sectors
= part
->data_sectors_per_block
;
300 part
->blocks
[block
].used_sectors
= 0;
301 part
->blocks
[block
].erases
++;
303 rc
= mtd_write(part
->mbd
.mtd
, part
->blocks
[block
].offset
,
304 sizeof(magic
), &retlen
, (u_char
*)&magic
);
305 if (!rc
&& retlen
!= sizeof(magic
))
309 pr_err(PREFIX
"'%s': unable to write RFD header at 0x%lx\n",
310 part
->mbd
.mtd
->name
, part
->blocks
[block
].offset
);
311 part
->blocks
[block
].state
= BLOCK_FAILED
;
313 part
->blocks
[block
].state
= BLOCK_OK
;
322 static int move_block_contents(struct partition
*part
, int block_no
, u_long
*old_sector
)
329 part
->is_reclaiming
= 1;
331 sector_data
= kmalloc(SECTOR_SIZE
, GFP_KERNEL
);
335 map
= kmalloc(part
->header_size
, GFP_KERNEL
);
339 rc
= mtd_read(part
->mbd
.mtd
, part
->blocks
[block_no
].offset
,
340 part
->header_size
, &retlen
, (u_char
*)map
);
342 if (!rc
&& retlen
!= part
->header_size
)
346 printk(KERN_ERR PREFIX
"error reading '%s' at "
347 "0x%lx\n", part
->mbd
.mtd
->name
,
348 part
->blocks
[block_no
].offset
);
353 for (i
=0; i
<part
->data_sectors_per_block
; i
++) {
354 u16 entry
= le16_to_cpu(map
[HEADER_MAP_OFFSET
+ i
]);
358 if (entry
== SECTOR_FREE
|| entry
== SECTOR_DELETED
)
361 if (entry
== SECTOR_ZERO
)
364 /* already warned about and ignored in build_block_map() */
365 if (entry
>= part
->sector_count
)
368 addr
= part
->blocks
[block_no
].offset
+
369 (i
+ part
->header_sectors_per_block
) * SECTOR_SIZE
;
371 if (*old_sector
== addr
) {
373 if (!part
->blocks
[block_no
].used_sectors
--) {
374 rc
= erase_block(part
, block_no
);
379 rc
= mtd_read(part
->mbd
.mtd
, addr
, SECTOR_SIZE
, &retlen
,
382 if (!rc
&& retlen
!= SECTOR_SIZE
)
386 printk(KERN_ERR PREFIX
"'%s': Unable to "
387 "read sector for relocation\n",
388 part
->mbd
.mtd
->name
);
393 rc
= rfd_ftl_writesect((struct mtd_blktrans_dev
*)part
,
405 part
->is_reclaiming
= 0;
410 static int reclaim_block(struct partition
*part
, u_long
*old_sector
)
412 int block
, best_block
, score
, old_sector_block
;
415 /* we have a race if sync doesn't exist */
416 mtd_sync(part
->mbd
.mtd
);
418 score
= 0x7fffffff; /* MAX_INT */
420 if (*old_sector
!= -1)
421 old_sector_block
= *old_sector
/ part
->block_size
;
423 old_sector_block
= -1;
425 for (block
=0; block
<part
->total_blocks
; block
++) {
428 if (block
== part
->reserved_block
)
432 * Postpone reclaiming if there is a free sector as
433 * more removed sectors is more efficient (have to move
436 if (part
->blocks
[block
].free_sectors
)
439 this_score
= part
->blocks
[block
].used_sectors
;
441 if (block
== old_sector_block
)
444 /* no point in moving a full block */
445 if (part
->blocks
[block
].used_sectors
==
446 part
->data_sectors_per_block
)
450 this_score
+= part
->blocks
[block
].erases
;
452 if (this_score
< score
) {
458 if (best_block
== -1)
461 part
->current_block
= -1;
462 part
->reserved_block
= best_block
;
464 pr_debug("reclaim_block: reclaiming block #%d with %d used "
465 "%d free sectors\n", best_block
,
466 part
->blocks
[best_block
].used_sectors
,
467 part
->blocks
[best_block
].free_sectors
);
469 if (part
->blocks
[best_block
].used_sectors
)
470 rc
= move_block_contents(part
, best_block
, old_sector
);
472 rc
= erase_block(part
, best_block
);
478 * IMPROVE: It would be best to choose the block with the most deleted sectors,
479 * because if we fill that one up first it'll have the most chance of having
480 * the least live sectors at reclaim.
482 static int find_free_block(struct partition
*part
)
486 block
= part
->current_block
== -1 ?
487 jiffies
% part
->total_blocks
: part
->current_block
;
491 if (part
->blocks
[block
].free_sectors
&&
492 block
!= part
->reserved_block
)
495 if (part
->blocks
[block
].state
== BLOCK_UNUSED
)
496 erase_block(part
, block
);
498 if (++block
>= part
->total_blocks
)
501 } while (block
!= stop
);
506 static int find_writable_block(struct partition
*part
, u_long
*old_sector
)
511 block
= find_free_block(part
);
514 if (!part
->is_reclaiming
) {
515 rc
= reclaim_block(part
, old_sector
);
519 block
= find_free_block(part
);
528 rc
= mtd_read(part
->mbd
.mtd
, part
->blocks
[block
].offset
,
529 part
->header_size
, &retlen
,
530 (u_char
*)part
->header_cache
);
532 if (!rc
&& retlen
!= part
->header_size
)
536 printk(KERN_ERR PREFIX
"'%s': unable to read header at "
537 "0x%lx\n", part
->mbd
.mtd
->name
,
538 part
->blocks
[block
].offset
);
542 part
->current_block
= block
;
548 static int mark_sector_deleted(struct partition
*part
, u_long old_addr
)
550 int block
, offset
, rc
;
553 u16 del
= cpu_to_le16(SECTOR_DELETED
);
555 block
= old_addr
/ part
->block_size
;
556 offset
= (old_addr
% part
->block_size
) / SECTOR_SIZE
-
557 part
->header_sectors_per_block
;
559 addr
= part
->blocks
[block
].offset
+
560 (HEADER_MAP_OFFSET
+ offset
) * sizeof(u16
);
561 rc
= mtd_write(part
->mbd
.mtd
, addr
, sizeof(del
), &retlen
,
564 if (!rc
&& retlen
!= sizeof(del
))
568 printk(KERN_ERR PREFIX
"error writing '%s' at "
569 "0x%lx\n", part
->mbd
.mtd
->name
, addr
);
572 if (block
== part
->current_block
)
573 part
->header_cache
[offset
+ HEADER_MAP_OFFSET
] = del
;
575 part
->blocks
[block
].used_sectors
--;
577 if (!part
->blocks
[block
].used_sectors
&&
578 !part
->blocks
[block
].free_sectors
)
579 rc
= erase_block(part
, block
);
585 static int find_free_sector(const struct partition
*part
, const struct block
*block
)
589 i
= stop
= part
->data_sectors_per_block
- block
->free_sectors
;
592 if (le16_to_cpu(part
->header_cache
[HEADER_MAP_OFFSET
+ i
])
596 if (++i
== part
->data_sectors_per_block
)
604 static int do_writesect(struct mtd_blktrans_dev
*dev
, u_long sector
, char *buf
, ulong
*old_addr
)
606 struct partition
*part
= (struct partition
*)dev
;
614 if (part
->current_block
== -1 ||
615 !part
->blocks
[part
->current_block
].free_sectors
) {
617 rc
= find_writable_block(part
, old_addr
);
622 block
= &part
->blocks
[part
->current_block
];
624 i
= find_free_sector(part
, block
);
631 addr
= (i
+ part
->header_sectors_per_block
) * SECTOR_SIZE
+
633 rc
= mtd_write(part
->mbd
.mtd
, addr
, SECTOR_SIZE
, &retlen
,
636 if (!rc
&& retlen
!= SECTOR_SIZE
)
640 printk(KERN_ERR PREFIX
"error writing '%s' at 0x%lx\n",
641 part
->mbd
.mtd
->name
, addr
);
645 part
->sector_map
[sector
] = addr
;
647 entry
= cpu_to_le16(sector
== 0 ? SECTOR_ZERO
: sector
);
649 part
->header_cache
[i
+ HEADER_MAP_OFFSET
] = entry
;
651 addr
= block
->offset
+ (HEADER_MAP_OFFSET
+ i
) * sizeof(u16
);
652 rc
= mtd_write(part
->mbd
.mtd
, addr
, sizeof(entry
), &retlen
,
655 if (!rc
&& retlen
!= sizeof(entry
))
659 printk(KERN_ERR PREFIX
"error writing '%s' at 0x%lx\n",
660 part
->mbd
.mtd
->name
, addr
);
663 block
->used_sectors
++;
664 block
->free_sectors
--;
670 static int rfd_ftl_writesect(struct mtd_blktrans_dev
*dev
, u_long sector
, char *buf
)
672 struct partition
*part
= (struct partition
*)dev
;
677 pr_debug("rfd_ftl_writesect(sector=0x%lx)\n", sector
);
679 if (part
->reserved_block
== -1) {
684 if (sector
>= part
->sector_count
) {
689 old_addr
= part
->sector_map
[sector
];
691 for (i
=0; i
<SECTOR_SIZE
; i
++) {
695 rc
= do_writesect(dev
, sector
, buf
, &old_addr
);
701 if (i
== SECTOR_SIZE
)
702 part
->sector_map
[sector
] = -1;
705 rc
= mark_sector_deleted(part
, old_addr
);
711 static int rfd_ftl_getgeo(struct mtd_blktrans_dev
*dev
, struct hd_geometry
*geo
)
713 struct partition
*part
= (struct partition
*)dev
;
716 geo
->sectors
= SECTORS_PER_TRACK
;
717 geo
->cylinders
= part
->cylinders
;
722 static void rfd_ftl_add_mtd(struct mtd_blktrans_ops
*tr
, struct mtd_info
*mtd
)
724 struct partition
*part
;
726 if (mtd
->type
!= MTD_NORFLASH
|| mtd
->size
> UINT_MAX
)
729 part
= kzalloc(sizeof(struct partition
), GFP_KERNEL
);
736 part
->block_size
= block_size
;
738 if (!mtd
->erasesize
) {
739 printk(KERN_WARNING PREFIX
"please provide block_size");
742 part
->block_size
= mtd
->erasesize
;
745 if (scan_header(part
) == 0) {
746 part
->mbd
.size
= part
->sector_count
;
748 part
->mbd
.devnum
= -1;
749 if (!(mtd
->flags
& MTD_WRITEABLE
))
750 part
->mbd
.readonly
= 1;
751 else if (part
->errors
) {
752 printk(KERN_WARNING PREFIX
"'%s': errors found, "
753 "setting read-only\n", mtd
->name
);
754 part
->mbd
.readonly
= 1;
757 printk(KERN_INFO PREFIX
"name: '%s' type: %d flags %x\n",
758 mtd
->name
, mtd
->type
, mtd
->flags
);
760 if (!add_mtd_blktrans_dev((void*)part
))
767 static void rfd_ftl_remove_dev(struct mtd_blktrans_dev
*dev
)
769 struct partition
*part
= (struct partition
*)dev
;
772 for (i
=0; i
<part
->total_blocks
; i
++) {
773 pr_debug("rfd_ftl_remove_dev:'%s': erase unit #%02d: %d erases\n",
774 part
->mbd
.mtd
->name
, i
, part
->blocks
[i
].erases
);
777 del_mtd_blktrans_dev(dev
);
778 vfree(part
->sector_map
);
779 kfree(part
->header_cache
);
783 static struct mtd_blktrans_ops rfd_ftl_tr
= {
785 .major
= RFD_FTL_MAJOR
,
786 .part_bits
= PART_BITS
,
787 .blksize
= SECTOR_SIZE
,
789 .readsect
= rfd_ftl_readsect
,
790 .writesect
= rfd_ftl_writesect
,
791 .getgeo
= rfd_ftl_getgeo
,
792 .add_mtd
= rfd_ftl_add_mtd
,
793 .remove_dev
= rfd_ftl_remove_dev
,
794 .owner
= THIS_MODULE
,
797 static int __init
init_rfd_ftl(void)
799 return register_mtd_blktrans(&rfd_ftl_tr
);
802 static void __exit
cleanup_rfd_ftl(void)
804 deregister_mtd_blktrans(&rfd_ftl_tr
);
807 module_init(init_rfd_ftl
);
808 module_exit(cleanup_rfd_ftl
);
810 MODULE_LICENSE("GPL");
811 MODULE_AUTHOR("Sean Young <sean@mess.org>");
812 MODULE_DESCRIPTION("Support code for RFD Flash Translation Layer, "
813 "used by General Software's Embedded BIOS");