GNU Linux-libre 4.19.264-gnu1
[releases.git] / drivers / mtd / rfd_ftl.c
1 /*
2  * rfd_ftl.c -- resident flash disk (flash translation layer)
3  *
4  * Copyright © 2005  Sean Young <sean@mess.org>
5  *
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:
8  *
9  *      http://www.gensw.com/pages/prod/bios/rfd.htm
10  *
11  * based on ftl.c
12  */
13
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>
22
23 #include <asm/types.h>
24
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");
28
29 #define PREFIX "rfd_ftl: "
30
31 /* This major has been assigned by device@lanana.org */
32 #ifndef RFD_FTL_MAJOR
33 #define RFD_FTL_MAJOR           256
34 #endif
35
36 /* Maximum number of partitions in an FTL region */
37 #define PART_BITS               4
38
39 /* An erase unit should start with this value */
40 #define RFD_MAGIC               0x9193
41
42 /* the second value is 0xffff or 0xffc8; function unknown */
43
44 /* the third value is always 0xffff, ignored */
45
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
51
52 #define SECTOR_SIZE             512
53
54 #define SECTORS_PER_TRACK       63
55
56 struct block {
57         enum {
58                 BLOCK_OK,
59                 BLOCK_ERASING,
60                 BLOCK_ERASED,
61                 BLOCK_UNUSED,
62                 BLOCK_FAILED
63         } state;
64         int free_sectors;
65         int used_sectors;
66         int erases;
67         u_long offset;
68 };
69
70 struct partition {
71         struct mtd_blktrans_dev mbd;
72
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 */
82
83         int is_reclaiming;
84         int cylinders;
85         int errors;
86         u_long *sector_map;
87         struct block *blocks;
88 };
89
90 static int rfd_ftl_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf);
91
92 static int build_block_map(struct partition *part, int block_no)
93 {
94         struct block *block = &part->blocks[block_no];
95         int i;
96
97         block->offset = part->block_size * block_no;
98
99         if (le16_to_cpu(part->header_cache[0]) != RFD_MAGIC) {
100                 block->state = BLOCK_UNUSED;
101                 return -ENOENT;
102         }
103
104         block->state = BLOCK_OK;
105
106         for (i=0; i<part->data_sectors_per_block; i++) {
107                 u16 entry;
108
109                 entry = le16_to_cpu(part->header_cache[HEADER_MAP_OFFSET + i]);
110
111                 if (entry == SECTOR_DELETED)
112                         continue;
113
114                 if (entry == SECTOR_FREE) {
115                         block->free_sectors++;
116                         continue;
117                 }
118
119                 if (entry == SECTOR_ZERO)
120                         entry = 0;
121
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);
127                         continue;
128                 }
129
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);
134                         part->errors = 1;
135                         continue;
136                 }
137
138                 part->sector_map[entry] = block->offset +
139                         (i + part->header_sectors_per_block) * SECTOR_SIZE;
140
141                 block->used_sectors++;
142         }
143
144         if (block->free_sectors == part->data_sectors_per_block)
145                 part->reserved_block = block_no;
146
147         return 0;
148 }
149
150 static int scan_header(struct partition *part)
151 {
152         int sectors_per_block;
153         int i, rc = -ENOMEM;
154         int blocks_found;
155         size_t retlen;
156
157         sectors_per_block = part->block_size / SECTOR_SIZE;
158         part->total_blocks = (u32)part->mbd.mtd->size / part->block_size;
159
160         if (part->total_blocks < 2)
161                 return -ENOENT;
162
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;
167
168         part->data_sectors_per_block = sectors_per_block -
169                         part->header_sectors_per_block;
170
171         part->header_size = (HEADER_MAP_OFFSET +
172                         part->data_sectors_per_block) * sizeof(u16);
173
174         part->cylinders = (part->data_sectors_per_block *
175                         (part->total_blocks - 1) - 1) / SECTORS_PER_TRACK;
176
177         part->sector_count = part->cylinders * SECTORS_PER_TRACK;
178
179         part->current_block = -1;
180         part->reserved_block = -1;
181         part->is_reclaiming = 0;
182
183         part->header_cache = kmalloc(part->header_size, GFP_KERNEL);
184         if (!part->header_cache)
185                 goto err;
186
187         part->blocks = kcalloc(part->total_blocks, sizeof(struct block),
188                         GFP_KERNEL);
189         if (!part->blocks)
190                 goto err;
191
192         part->sector_map = vmalloc(array_size(sizeof(u_long),
193                                               part->sector_count));
194         if (!part->sector_map) {
195                 printk(KERN_ERR PREFIX "'%s': unable to allocate memory for "
196                         "sector map", part->mbd.mtd->name);
197                 goto err;
198         }
199
200         for (i=0; i<part->sector_count; i++)
201                 part->sector_map[i] = -1;
202
203         for (i=0, blocks_found=0; i<part->total_blocks; i++) {
204                 rc = mtd_read(part->mbd.mtd, i * part->block_size,
205                               part->header_size, &retlen,
206                               (u_char *)part->header_cache);
207
208                 if (!rc && retlen != part->header_size)
209                         rc = -EIO;
210
211                 if (rc)
212                         goto err;
213
214                 if (!build_block_map(part, i))
215                         blocks_found++;
216         }
217
218         if (blocks_found == 0) {
219                 printk(KERN_NOTICE PREFIX "no RFD magic found in '%s'\n",
220                                 part->mbd.mtd->name);
221                 rc = -ENOENT;
222                 goto err;
223         }
224
225         if (part->reserved_block == -1) {
226                 printk(KERN_WARNING PREFIX "'%s': no empty erase unit found\n",
227                                 part->mbd.mtd->name);
228
229                 part->errors = 1;
230         }
231
232         return 0;
233
234 err:
235         vfree(part->sector_map);
236         kfree(part->header_cache);
237         kfree(part->blocks);
238
239         return rc;
240 }
241
242 static int rfd_ftl_readsect(struct mtd_blktrans_dev *dev, u_long sector, char *buf)
243 {
244         struct partition *part = (struct partition*)dev;
245         u_long addr;
246         size_t retlen;
247         int rc;
248
249         if (sector >= part->sector_count)
250                 return -EIO;
251
252         addr = part->sector_map[sector];
253         if (addr != -1) {
254                 rc = mtd_read(part->mbd.mtd, addr, SECTOR_SIZE, &retlen,
255                               (u_char *)buf);
256                 if (!rc && retlen != SECTOR_SIZE)
257                         rc = -EIO;
258
259                 if (rc) {
260                         printk(KERN_WARNING PREFIX "error reading '%s' at "
261                                 "0x%lx\n", part->mbd.mtd->name, addr);
262                         return rc;
263                 }
264         } else
265                 memset(buf, 0, SECTOR_SIZE);
266
267         return 0;
268 }
269
270 static int erase_block(struct partition *part, int block)
271 {
272         struct erase_info *erase;
273         int rc;
274
275         erase = kmalloc(sizeof(struct erase_info), GFP_KERNEL);
276         if (!erase)
277                 return -ENOMEM;
278
279         erase->addr = part->blocks[block].offset;
280         erase->len = part->block_size;
281
282         part->blocks[block].state = BLOCK_ERASING;
283         part->blocks[block].free_sectors = 0;
284
285         rc = mtd_erase(part->mbd.mtd, erase);
286         if (rc) {
287                 printk(KERN_ERR PREFIX "erase of region %llx,%llx on '%s' "
288                                 "failed\n", (unsigned long long)erase->addr,
289                                 (unsigned long long)erase->len, part->mbd.mtd->name);
290                 part->blocks[block].state = BLOCK_FAILED;
291                 part->blocks[block].free_sectors = 0;
292                 part->blocks[block].used_sectors = 0;
293         } else {
294                 u16 magic = cpu_to_le16(RFD_MAGIC);
295                 size_t retlen;
296
297                 part->blocks[block].state = BLOCK_ERASED;
298                 part->blocks[block].free_sectors = part->data_sectors_per_block;
299                 part->blocks[block].used_sectors = 0;
300                 part->blocks[block].erases++;
301
302                 rc = mtd_write(part->mbd.mtd, part->blocks[block].offset,
303                                sizeof(magic), &retlen, (u_char *)&magic);
304                 if (!rc && retlen != sizeof(magic))
305                         rc = -EIO;
306
307                 if (rc) {
308                         pr_err(PREFIX "'%s': unable to write RFD header at 0x%lx\n",
309                                part->mbd.mtd->name, part->blocks[block].offset);
310                         part->blocks[block].state = BLOCK_FAILED;
311                 } else {
312                         part->blocks[block].state = BLOCK_OK;
313                 }
314         }
315
316         kfree(erase);
317
318         return rc;
319 }
320
321 static int move_block_contents(struct partition *part, int block_no, u_long *old_sector)
322 {
323         void *sector_data;
324         u16 *map;
325         size_t retlen;
326         int i, rc = -ENOMEM;
327
328         part->is_reclaiming = 1;
329
330         sector_data = kmalloc(SECTOR_SIZE, GFP_KERNEL);
331         if (!sector_data)
332                 goto err3;
333
334         map = kmalloc(part->header_size, GFP_KERNEL);
335         if (!map)
336                 goto err2;
337
338         rc = mtd_read(part->mbd.mtd, part->blocks[block_no].offset,
339                       part->header_size, &retlen, (u_char *)map);
340
341         if (!rc && retlen != part->header_size)
342                 rc = -EIO;
343
344         if (rc) {
345                 printk(KERN_ERR PREFIX "error reading '%s' at "
346                         "0x%lx\n", part->mbd.mtd->name,
347                         part->blocks[block_no].offset);
348
349                 goto err;
350         }
351
352         for (i=0; i<part->data_sectors_per_block; i++) {
353                 u16 entry = le16_to_cpu(map[HEADER_MAP_OFFSET + i]);
354                 u_long addr;
355
356
357                 if (entry == SECTOR_FREE || entry == SECTOR_DELETED)
358                         continue;
359
360                 if (entry == SECTOR_ZERO)
361                         entry = 0;
362
363                 /* already warned about and ignored in build_block_map() */
364                 if (entry >= part->sector_count)
365                         continue;
366
367                 addr = part->blocks[block_no].offset +
368                         (i + part->header_sectors_per_block) * SECTOR_SIZE;
369
370                 if (*old_sector == addr) {
371                         *old_sector = -1;
372                         if (!part->blocks[block_no].used_sectors--) {
373                                 rc = erase_block(part, block_no);
374                                 break;
375                         }
376                         continue;
377                 }
378                 rc = mtd_read(part->mbd.mtd, addr, SECTOR_SIZE, &retlen,
379                               sector_data);
380
381                 if (!rc && retlen != SECTOR_SIZE)
382                         rc = -EIO;
383
384                 if (rc) {
385                         printk(KERN_ERR PREFIX "'%s': Unable to "
386                                 "read sector for relocation\n",
387                                 part->mbd.mtd->name);
388
389                         goto err;
390                 }
391
392                 rc = rfd_ftl_writesect((struct mtd_blktrans_dev*)part,
393                                 entry, sector_data);
394
395                 if (rc)
396                         goto err;
397         }
398
399 err:
400         kfree(map);
401 err2:
402         kfree(sector_data);
403 err3:
404         part->is_reclaiming = 0;
405
406         return rc;
407 }
408
409 static int reclaim_block(struct partition *part, u_long *old_sector)
410 {
411         int block, best_block, score, old_sector_block;
412         int rc;
413
414         /* we have a race if sync doesn't exist */
415         mtd_sync(part->mbd.mtd);
416
417         score = 0x7fffffff; /* MAX_INT */
418         best_block = -1;
419         if (*old_sector != -1)
420                 old_sector_block = *old_sector / part->block_size;
421         else
422                 old_sector_block = -1;
423
424         for (block=0; block<part->total_blocks; block++) {
425                 int this_score;
426
427                 if (block == part->reserved_block)
428                         continue;
429
430                 /*
431                  * Postpone reclaiming if there is a free sector as
432                  * more removed sectors is more efficient (have to move
433                  * less).
434                  */
435                 if (part->blocks[block].free_sectors)
436                         return 0;
437
438                 this_score = part->blocks[block].used_sectors;
439
440                 if (block == old_sector_block)
441                         this_score--;
442                 else {
443                         /* no point in moving a full block */
444                         if (part->blocks[block].used_sectors ==
445                                         part->data_sectors_per_block)
446                                 continue;
447                 }
448
449                 this_score += part->blocks[block].erases;
450
451                 if (this_score < score) {
452                         best_block = block;
453                         score = this_score;
454                 }
455         }
456
457         if (best_block == -1)
458                 return -ENOSPC;
459
460         part->current_block = -1;
461         part->reserved_block = best_block;
462
463         pr_debug("reclaim_block: reclaiming block #%d with %d used "
464                  "%d free sectors\n", best_block,
465                  part->blocks[best_block].used_sectors,
466                  part->blocks[best_block].free_sectors);
467
468         if (part->blocks[best_block].used_sectors)
469                 rc = move_block_contents(part, best_block, old_sector);
470         else
471                 rc = erase_block(part, best_block);
472
473         return rc;
474 }
475
476 /*
477  * IMPROVE: It would be best to choose the block with the most deleted sectors,
478  * because if we fill that one up first it'll have the most chance of having
479  * the least live sectors at reclaim.
480  */
481 static int find_free_block(struct partition *part)
482 {
483         int block, stop;
484
485         block = part->current_block == -1 ?
486                         jiffies % part->total_blocks : part->current_block;
487         stop = block;
488
489         do {
490                 if (part->blocks[block].free_sectors &&
491                                 block != part->reserved_block)
492                         return block;
493
494                 if (part->blocks[block].state == BLOCK_UNUSED)
495                         erase_block(part, block);
496
497                 if (++block >= part->total_blocks)
498                         block = 0;
499
500         } while (block != stop);
501
502         return -1;
503 }
504
505 static int find_writable_block(struct partition *part, u_long *old_sector)
506 {
507         int rc, block;
508         size_t retlen;
509
510         block = find_free_block(part);
511
512         if (block == -1) {
513                 if (!part->is_reclaiming) {
514                         rc = reclaim_block(part, old_sector);
515                         if (rc)
516                                 goto err;
517
518                         block = find_free_block(part);
519                 }
520
521                 if (block == -1) {
522                         rc = -ENOSPC;
523                         goto err;
524                 }
525         }
526
527         rc = mtd_read(part->mbd.mtd, part->blocks[block].offset,
528                       part->header_size, &retlen,
529                       (u_char *)part->header_cache);
530
531         if (!rc && retlen != part->header_size)
532                 rc = -EIO;
533
534         if (rc) {
535                 printk(KERN_ERR PREFIX "'%s': unable to read header at "
536                                 "0x%lx\n", part->mbd.mtd->name,
537                                 part->blocks[block].offset);
538                 goto err;
539         }
540
541         part->current_block = block;
542
543 err:
544         return rc;
545 }
546
547 static int mark_sector_deleted(struct partition *part, u_long old_addr)
548 {
549         int block, offset, rc;
550         u_long addr;
551         size_t retlen;
552         u16 del = cpu_to_le16(SECTOR_DELETED);
553
554         block = old_addr / part->block_size;
555         offset = (old_addr % part->block_size) / SECTOR_SIZE -
556                 part->header_sectors_per_block;
557
558         addr = part->blocks[block].offset +
559                         (HEADER_MAP_OFFSET + offset) * sizeof(u16);
560         rc = mtd_write(part->mbd.mtd, addr, sizeof(del), &retlen,
561                        (u_char *)&del);
562
563         if (!rc && retlen != sizeof(del))
564                 rc = -EIO;
565
566         if (rc) {
567                 printk(KERN_ERR PREFIX "error writing '%s' at "
568                         "0x%lx\n", part->mbd.mtd->name, addr);
569                 goto err;
570         }
571         if (block == part->current_block)
572                 part->header_cache[offset + HEADER_MAP_OFFSET] = del;
573
574         part->blocks[block].used_sectors--;
575
576         if (!part->blocks[block].used_sectors &&
577             !part->blocks[block].free_sectors)
578                 rc = erase_block(part, block);
579
580 err:
581         return rc;
582 }
583
584 static int find_free_sector(const struct partition *part, const struct block *block)
585 {
586         int i, stop;
587
588         i = stop = part->data_sectors_per_block - block->free_sectors;
589
590         do {
591                 if (le16_to_cpu(part->header_cache[HEADER_MAP_OFFSET + i])
592                                 == SECTOR_FREE)
593                         return i;
594
595                 if (++i == part->data_sectors_per_block)
596                         i = 0;
597         }
598         while(i != stop);
599
600         return -1;
601 }
602
603 static int do_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf, ulong *old_addr)
604 {
605         struct partition *part = (struct partition*)dev;
606         struct block *block;
607         u_long addr;
608         int i;
609         int rc;
610         size_t retlen;
611         u16 entry;
612
613         if (part->current_block == -1 ||
614                 !part->blocks[part->current_block].free_sectors) {
615
616                 rc = find_writable_block(part, old_addr);
617                 if (rc)
618                         goto err;
619         }
620
621         block = &part->blocks[part->current_block];
622
623         i = find_free_sector(part, block);
624
625         if (i < 0) {
626                 rc = -ENOSPC;
627                 goto err;
628         }
629
630         addr = (i + part->header_sectors_per_block) * SECTOR_SIZE +
631                 block->offset;
632         rc = mtd_write(part->mbd.mtd, addr, SECTOR_SIZE, &retlen,
633                        (u_char *)buf);
634
635         if (!rc && retlen != SECTOR_SIZE)
636                 rc = -EIO;
637
638         if (rc) {
639                 printk(KERN_ERR PREFIX "error writing '%s' at 0x%lx\n",
640                                 part->mbd.mtd->name, addr);
641                 goto err;
642         }
643
644         part->sector_map[sector] = addr;
645
646         entry = cpu_to_le16(sector == 0 ? SECTOR_ZERO : sector);
647
648         part->header_cache[i + HEADER_MAP_OFFSET] = entry;
649
650         addr = block->offset + (HEADER_MAP_OFFSET + i) * sizeof(u16);
651         rc = mtd_write(part->mbd.mtd, addr, sizeof(entry), &retlen,
652                        (u_char *)&entry);
653
654         if (!rc && retlen != sizeof(entry))
655                 rc = -EIO;
656
657         if (rc) {
658                 printk(KERN_ERR PREFIX "error writing '%s' at 0x%lx\n",
659                                 part->mbd.mtd->name, addr);
660                 goto err;
661         }
662         block->used_sectors++;
663         block->free_sectors--;
664
665 err:
666         return rc;
667 }
668
669 static int rfd_ftl_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf)
670 {
671         struct partition *part = (struct partition*)dev;
672         u_long old_addr;
673         int i;
674         int rc = 0;
675
676         pr_debug("rfd_ftl_writesect(sector=0x%lx)\n", sector);
677
678         if (part->reserved_block == -1) {
679                 rc = -EACCES;
680                 goto err;
681         }
682
683         if (sector >= part->sector_count) {
684                 rc = -EIO;
685                 goto err;
686         }
687
688         old_addr = part->sector_map[sector];
689
690         for (i=0; i<SECTOR_SIZE; i++) {
691                 if (!buf[i])
692                         continue;
693
694                 rc = do_writesect(dev, sector, buf, &old_addr);
695                 if (rc)
696                         goto err;
697                 break;
698         }
699
700         if (i == SECTOR_SIZE)
701                 part->sector_map[sector] = -1;
702
703         if (old_addr != -1)
704                 rc = mark_sector_deleted(part, old_addr);
705
706 err:
707         return rc;
708 }
709
710 static int rfd_ftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
711 {
712         struct partition *part = (struct partition*)dev;
713
714         geo->heads = 1;
715         geo->sectors = SECTORS_PER_TRACK;
716         geo->cylinders = part->cylinders;
717
718         return 0;
719 }
720
721 static void rfd_ftl_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
722 {
723         struct partition *part;
724
725         if (mtd->type != MTD_NORFLASH || mtd->size > UINT_MAX)
726                 return;
727
728         part = kzalloc(sizeof(struct partition), GFP_KERNEL);
729         if (!part)
730                 return;
731
732         part->mbd.mtd = mtd;
733
734         if (block_size)
735                 part->block_size = block_size;
736         else {
737                 if (!mtd->erasesize) {
738                         printk(KERN_WARNING PREFIX "please provide block_size");
739                         goto out;
740                 } else
741                         part->block_size = mtd->erasesize;
742         }
743
744         if (scan_header(part) == 0) {
745                 part->mbd.size = part->sector_count;
746                 part->mbd.tr = tr;
747                 part->mbd.devnum = -1;
748                 if (!(mtd->flags & MTD_WRITEABLE))
749                         part->mbd.readonly = 1;
750                 else if (part->errors) {
751                         printk(KERN_WARNING PREFIX "'%s': errors found, "
752                                         "setting read-only\n", mtd->name);
753                         part->mbd.readonly = 1;
754                 }
755
756                 printk(KERN_INFO PREFIX "name: '%s' type: %d flags %x\n",
757                                 mtd->name, mtd->type, mtd->flags);
758
759                 if (!add_mtd_blktrans_dev((void*)part))
760                         return;
761         }
762 out:
763         kfree(part);
764 }
765
766 static void rfd_ftl_remove_dev(struct mtd_blktrans_dev *dev)
767 {
768         struct partition *part = (struct partition*)dev;
769         int i;
770
771         for (i=0; i<part->total_blocks; i++) {
772                 pr_debug("rfd_ftl_remove_dev:'%s': erase unit #%02d: %d erases\n",
773                         part->mbd.mtd->name, i, part->blocks[i].erases);
774         }
775
776         del_mtd_blktrans_dev(dev);
777         vfree(part->sector_map);
778         kfree(part->header_cache);
779         kfree(part->blocks);
780 }
781
782 static struct mtd_blktrans_ops rfd_ftl_tr = {
783         .name           = "rfd",
784         .major          = RFD_FTL_MAJOR,
785         .part_bits      = PART_BITS,
786         .blksize        = SECTOR_SIZE,
787
788         .readsect       = rfd_ftl_readsect,
789         .writesect      = rfd_ftl_writesect,
790         .getgeo         = rfd_ftl_getgeo,
791         .add_mtd        = rfd_ftl_add_mtd,
792         .remove_dev     = rfd_ftl_remove_dev,
793         .owner          = THIS_MODULE,
794 };
795
796 static int __init init_rfd_ftl(void)
797 {
798         return register_mtd_blktrans(&rfd_ftl_tr);
799 }
800
801 static void __exit cleanup_rfd_ftl(void)
802 {
803         deregister_mtd_blktrans(&rfd_ftl_tr);
804 }
805
806 module_init(init_rfd_ftl);
807 module_exit(cleanup_rfd_ftl);
808
809 MODULE_LICENSE("GPL");
810 MODULE_AUTHOR("Sean Young <sean@mess.org>");
811 MODULE_DESCRIPTION("Support code for RFD Flash Translation Layer, "
812                 "used by General Software's Embedded BIOS");
813