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Linux 4.19.133
[linux/fpc-iii.git] / drivers / mtd / rfd_ftl.c
blob94720f2ca9a8a21a132d96f0a36687a7cd0bfe94
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
Linux with added FPC-III support