Merge branch 'master' of git://git.infradead.org/users/pcmoore/lblnet-2.6_next into...
[linux-2.6/mini2440.git] / drivers / mtd / rfd_ftl.c
blobe538c0a72abb0d531ddd992a559671d7020a7f5f
1 /*
2 * rfd_ftl.c -- resident flash disk (flash translation layer)
4 * Copyright (C) 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
11 * based on ftl.c
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>
22 #include <asm/types.h>
24 #define const_cpu_to_le16 __constant_cpu_to_le16
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 */
33 #ifndef RFD_FTL_MAJOR
34 #define RFD_FTL_MAJOR 256
35 #endif
37 /* Maximum number of partitions in an FTL region */
38 #define PART_BITS 4
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
57 struct block {
58 enum {
59 BLOCK_OK,
60 BLOCK_ERASING,
61 BLOCK_ERASED,
62 BLOCK_UNUSED,
63 BLOCK_FAILED
64 } state;
65 int free_sectors;
66 int used_sectors;
67 int erases;
68 u_long offset;
71 struct partition {
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 */
84 int is_reclaiming;
85 int cylinders;
86 int errors;
87 u_long *sector_map;
88 struct block *blocks;
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];
96 int i;
98 block->offset = part->block_size * block_no;
100 if (le16_to_cpu(part->header_cache[0]) != RFD_MAGIC) {
101 block->state = BLOCK_UNUSED;
102 return -ENOENT;
105 block->state = BLOCK_OK;
107 for (i=0; i<part->data_sectors_per_block; i++) {
108 u16 entry;
110 entry = le16_to_cpu(part->header_cache[HEADER_MAP_OFFSET + i]);
112 if (entry == SECTOR_DELETED)
113 continue;
115 if (entry == SECTOR_FREE) {
116 block->free_sectors++;
117 continue;
120 if (entry == SECTOR_ZERO)
121 entry = 0;
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);
128 continue;
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);
135 part->errors = 1;
136 continue;
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;
148 return 0;
151 static int scan_header(struct partition *part)
153 int sectors_per_block;
154 int i, rc = -ENOMEM;
155 int blocks_found;
156 size_t retlen;
158 sectors_per_block = part->block_size / SECTOR_SIZE;
159 part->total_blocks = part->mbd.mtd->size / part->block_size;
161 if (part->total_blocks < 2)
162 return -ENOENT;
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)
186 goto err;
188 part->blocks = kcalloc(part->total_blocks, sizeof(struct block),
189 GFP_KERNEL);
190 if (!part->blocks)
191 goto err;
193 part->sector_map = vmalloc(part->sector_count * sizeof(u_long));
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;
200 for (i=0; i<part->sector_count; i++)
201 part->sector_map[i] = -1;
203 for (i=0, blocks_found=0; i<part->total_blocks; i++) {
204 rc = part->mbd.mtd->read(part->mbd.mtd,
205 i * part->block_size, part->header_size,
206 &retlen, (u_char*)part->header_cache);
208 if (!rc && retlen != part->header_size)
209 rc = -EIO;
211 if (rc)
212 goto err;
214 if (!build_block_map(part, i))
215 blocks_found++;
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;
225 if (part->reserved_block == -1) {
226 printk(KERN_WARNING PREFIX "'%s': no empty erase unit found\n",
227 part->mbd.mtd->name);
229 part->errors = 1;
232 return 0;
234 err:
235 vfree(part->sector_map);
236 kfree(part->header_cache);
237 kfree(part->blocks);
239 return rc;
242 static int rfd_ftl_readsect(struct mtd_blktrans_dev *dev, u_long sector, char *buf)
244 struct partition *part = (struct partition*)dev;
245 u_long addr;
246 size_t retlen;
247 int rc;
249 if (sector >= part->sector_count)
250 return -EIO;
252 addr = part->sector_map[sector];
253 if (addr != -1) {
254 rc = part->mbd.mtd->read(part->mbd.mtd, addr, SECTOR_SIZE,
255 &retlen, (u_char*)buf);
256 if (!rc && retlen != SECTOR_SIZE)
257 rc = -EIO;
259 if (rc) {
260 printk(KERN_WARNING PREFIX "error reading '%s' at "
261 "0x%lx\n", part->mbd.mtd->name, addr);
262 return rc;
264 } else
265 memset(buf, 0, SECTOR_SIZE);
267 return 0;
270 static void erase_callback(struct erase_info *erase)
272 struct partition *part;
273 u16 magic;
274 int i, rc;
275 size_t retlen;
277 part = (struct partition*)erase->priv;
279 i = erase->addr / part->block_size;
280 if (i >= part->total_blocks || part->blocks[i].offset != erase->addr) {
281 printk(KERN_ERR PREFIX "erase callback for unknown offset %x "
282 "on '%s'\n", erase->addr, part->mbd.mtd->name);
283 return;
286 if (erase->state != MTD_ERASE_DONE) {
287 printk(KERN_WARNING PREFIX "erase failed at 0x%x on '%s', "
288 "state %d\n", 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;
295 kfree(erase);
297 return;
300 magic = const_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 = part->mbd.mtd->write(part->mbd.mtd,
308 part->blocks[i].offset, sizeof(magic), &retlen,
309 (u_char*)&magic);
311 if (!rc && retlen != sizeof(magic))
312 rc = -EIO;
314 if (rc) {
315 printk(KERN_ERR PREFIX "'%s': unable to write RFD "
316 "header at 0x%lx\n",
317 part->mbd.mtd->name,
318 part->blocks[i].offset);
319 part->blocks[i].state = BLOCK_FAILED;
321 else
322 part->blocks[i].state = BLOCK_OK;
324 kfree(erase);
327 static int erase_block(struct partition *part, int block)
329 struct erase_info *erase;
330 int rc = -ENOMEM;
332 erase = kmalloc(sizeof(struct erase_info), GFP_KERNEL);
333 if (!erase)
334 goto err;
336 erase->mtd = part->mbd.mtd;
337 erase->callback = erase_callback;
338 erase->addr = part->blocks[block].offset;
339 erase->len = part->block_size;
340 erase->priv = (u_long)part;
342 part->blocks[block].state = BLOCK_ERASING;
343 part->blocks[block].free_sectors = 0;
345 rc = part->mbd.mtd->erase(part->mbd.mtd, erase);
347 if (rc) {
348 printk(KERN_ERR PREFIX "erase of region %x,%x on '%s' "
349 "failed\n", erase->addr, erase->len,
350 part->mbd.mtd->name);
351 kfree(erase);
354 err:
355 return rc;
358 static int move_block_contents(struct partition *part, int block_no, u_long *old_sector)
360 void *sector_data;
361 u16 *map;
362 size_t retlen;
363 int i, rc = -ENOMEM;
365 part->is_reclaiming = 1;
367 sector_data = kmalloc(SECTOR_SIZE, GFP_KERNEL);
368 if (!sector_data)
369 goto err3;
371 map = kmalloc(part->header_size, GFP_KERNEL);
372 if (!map)
373 goto err2;
375 rc = part->mbd.mtd->read(part->mbd.mtd,
376 part->blocks[block_no].offset, part->header_size,
377 &retlen, (u_char*)map);
379 if (!rc && retlen != part->header_size)
380 rc = -EIO;
382 if (rc) {
383 printk(KERN_ERR PREFIX "error reading '%s' at "
384 "0x%lx\n", part->mbd.mtd->name,
385 part->blocks[block_no].offset);
387 goto err;
390 for (i=0; i<part->data_sectors_per_block; i++) {
391 u16 entry = le16_to_cpu(map[HEADER_MAP_OFFSET + i]);
392 u_long addr;
395 if (entry == SECTOR_FREE || entry == SECTOR_DELETED)
396 continue;
398 if (entry == SECTOR_ZERO)
399 entry = 0;
401 /* already warned about and ignored in build_block_map() */
402 if (entry >= part->sector_count)
403 continue;
405 addr = part->blocks[block_no].offset +
406 (i + part->header_sectors_per_block) * SECTOR_SIZE;
408 if (*old_sector == addr) {
409 *old_sector = -1;
410 if (!part->blocks[block_no].used_sectors--) {
411 rc = erase_block(part, block_no);
412 break;
414 continue;
416 rc = part->mbd.mtd->read(part->mbd.mtd, addr,
417 SECTOR_SIZE, &retlen, sector_data);
419 if (!rc && retlen != SECTOR_SIZE)
420 rc = -EIO;
422 if (rc) {
423 printk(KERN_ERR PREFIX "'%s': Unable to "
424 "read sector for relocation\n",
425 part->mbd.mtd->name);
427 goto err;
430 rc = rfd_ftl_writesect((struct mtd_blktrans_dev*)part,
431 entry, sector_data);
433 if (rc)
434 goto err;
437 err:
438 kfree(map);
439 err2:
440 kfree(sector_data);
441 err3:
442 part->is_reclaiming = 0;
444 return rc;
447 static int reclaim_block(struct partition *part, u_long *old_sector)
449 int block, best_block, score, old_sector_block;
450 int rc;
452 /* we have a race if sync doesn't exist */
453 if (part->mbd.mtd->sync)
454 part->mbd.mtd->sync(part->mbd.mtd);
456 score = 0x7fffffff; /* MAX_INT */
457 best_block = -1;
458 if (*old_sector != -1)
459 old_sector_block = *old_sector / part->block_size;
460 else
461 old_sector_block = -1;
463 for (block=0; block<part->total_blocks; block++) {
464 int this_score;
466 if (block == part->reserved_block)
467 continue;
470 * Postpone reclaiming if there is a free sector as
471 * more removed sectors is more efficient (have to move
472 * less).
474 if (part->blocks[block].free_sectors)
475 return 0;
477 this_score = part->blocks[block].used_sectors;
479 if (block == old_sector_block)
480 this_score--;
481 else {
482 /* no point in moving a full block */
483 if (part->blocks[block].used_sectors ==
484 part->data_sectors_per_block)
485 continue;
488 this_score += part->blocks[block].erases;
490 if (this_score < score) {
491 best_block = block;
492 score = this_score;
496 if (best_block == -1)
497 return -ENOSPC;
499 part->current_block = -1;
500 part->reserved_block = best_block;
502 pr_debug("reclaim_block: reclaiming block #%d with %d used "
503 "%d free sectors\n", best_block,
504 part->blocks[best_block].used_sectors,
505 part->blocks[best_block].free_sectors);
507 if (part->blocks[best_block].used_sectors)
508 rc = move_block_contents(part, best_block, old_sector);
509 else
510 rc = erase_block(part, best_block);
512 return rc;
516 * IMPROVE: It would be best to choose the block with the most deleted sectors,
517 * because if we fill that one up first it'll have the most chance of having
518 * the least live sectors at reclaim.
520 static int find_free_block(struct partition *part)
522 int block, stop;
524 block = part->current_block == -1 ?
525 jiffies % part->total_blocks : part->current_block;
526 stop = block;
528 do {
529 if (part->blocks[block].free_sectors &&
530 block != part->reserved_block)
531 return block;
533 if (part->blocks[block].state == BLOCK_UNUSED)
534 erase_block(part, block);
536 if (++block >= part->total_blocks)
537 block = 0;
539 } while (block != stop);
541 return -1;
544 static int find_writable_block(struct partition *part, u_long *old_sector)
546 int rc, block;
547 size_t retlen;
549 block = find_free_block(part);
551 if (block == -1) {
552 if (!part->is_reclaiming) {
553 rc = reclaim_block(part, old_sector);
554 if (rc)
555 goto err;
557 block = find_free_block(part);
560 if (block == -1) {
561 rc = -ENOSPC;
562 goto err;
566 rc = part->mbd.mtd->read(part->mbd.mtd, part->blocks[block].offset,
567 part->header_size, &retlen, (u_char*)part->header_cache);
569 if (!rc && retlen != part->header_size)
570 rc = -EIO;
572 if (rc) {
573 printk(KERN_ERR PREFIX "'%s': unable to read header at "
574 "0x%lx\n", part->mbd.mtd->name,
575 part->blocks[block].offset);
576 goto err;
579 part->current_block = block;
581 err:
582 return rc;
585 static int mark_sector_deleted(struct partition *part, u_long old_addr)
587 int block, offset, rc;
588 u_long addr;
589 size_t retlen;
590 u16 del = const_cpu_to_le16(SECTOR_DELETED);
592 block = old_addr / part->block_size;
593 offset = (old_addr % part->block_size) / SECTOR_SIZE -
594 part->header_sectors_per_block;
596 addr = part->blocks[block].offset +
597 (HEADER_MAP_OFFSET + offset) * sizeof(u16);
598 rc = part->mbd.mtd->write(part->mbd.mtd, addr,
599 sizeof(del), &retlen, (u_char*)&del);
601 if (!rc && retlen != sizeof(del))
602 rc = -EIO;
604 if (rc) {
605 printk(KERN_ERR PREFIX "error writing '%s' at "
606 "0x%lx\n", part->mbd.mtd->name, addr);
607 if (rc)
608 goto err;
610 if (block == part->current_block)
611 part->header_cache[offset + HEADER_MAP_OFFSET] = del;
613 part->blocks[block].used_sectors--;
615 if (!part->blocks[block].used_sectors &&
616 !part->blocks[block].free_sectors)
617 rc = erase_block(part, block);
619 err:
620 return rc;
623 static int find_free_sector(const struct partition *part, const struct block *block)
625 int i, stop;
627 i = stop = part->data_sectors_per_block - block->free_sectors;
629 do {
630 if (le16_to_cpu(part->header_cache[HEADER_MAP_OFFSET + i])
631 == SECTOR_FREE)
632 return i;
634 if (++i == part->data_sectors_per_block)
635 i = 0;
637 while(i != stop);
639 return -1;
642 static int do_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf, ulong *old_addr)
644 struct partition *part = (struct partition*)dev;
645 struct block *block;
646 u_long addr;
647 int i;
648 int rc;
649 size_t retlen;
650 u16 entry;
652 if (part->current_block == -1 ||
653 !part->blocks[part->current_block].free_sectors) {
655 rc = find_writable_block(part, old_addr);
656 if (rc)
657 goto err;
660 block = &part->blocks[part->current_block];
662 i = find_free_sector(part, block);
664 if (i < 0) {
665 rc = -ENOSPC;
666 goto err;
669 addr = (i + part->header_sectors_per_block) * SECTOR_SIZE +
670 block->offset;
671 rc = part->mbd.mtd->write(part->mbd.mtd,
672 addr, SECTOR_SIZE, &retlen, (u_char*)buf);
674 if (!rc && retlen != SECTOR_SIZE)
675 rc = -EIO;
677 if (rc) {
678 printk(KERN_ERR PREFIX "error writing '%s' at 0x%lx\n",
679 part->mbd.mtd->name, addr);
680 if (rc)
681 goto err;
684 part->sector_map[sector] = addr;
686 entry = cpu_to_le16(sector == 0 ? SECTOR_ZERO : sector);
688 part->header_cache[i + HEADER_MAP_OFFSET] = entry;
690 addr = block->offset + (HEADER_MAP_OFFSET + i) * sizeof(u16);
691 rc = part->mbd.mtd->write(part->mbd.mtd, addr,
692 sizeof(entry), &retlen, (u_char*)&entry);
694 if (!rc && retlen != sizeof(entry))
695 rc = -EIO;
697 if (rc) {
698 printk(KERN_ERR PREFIX "error writing '%s' at 0x%lx\n",
699 part->mbd.mtd->name, addr);
700 if (rc)
701 goto err;
703 block->used_sectors++;
704 block->free_sectors--;
706 err:
707 return rc;
710 static int rfd_ftl_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf)
712 struct partition *part = (struct partition*)dev;
713 u_long old_addr;
714 int i;
715 int rc = 0;
717 pr_debug("rfd_ftl_writesect(sector=0x%lx)\n", sector);
719 if (part->reserved_block == -1) {
720 rc = -EACCES;
721 goto err;
724 if (sector >= part->sector_count) {
725 rc = -EIO;
726 goto err;
729 old_addr = part->sector_map[sector];
731 for (i=0; i<SECTOR_SIZE; i++) {
732 if (!buf[i])
733 continue;
735 rc = do_writesect(dev, sector, buf, &old_addr);
736 if (rc)
737 goto err;
738 break;
741 if (i == SECTOR_SIZE)
742 part->sector_map[sector] = -1;
744 if (old_addr != -1)
745 rc = mark_sector_deleted(part, old_addr);
747 err:
748 return rc;
751 static int rfd_ftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
753 struct partition *part = (struct partition*)dev;
755 geo->heads = 1;
756 geo->sectors = SECTORS_PER_TRACK;
757 geo->cylinders = part->cylinders;
759 return 0;
762 static void rfd_ftl_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
764 struct partition *part;
766 if (mtd->type != MTD_NORFLASH)
767 return;
769 part = kzalloc(sizeof(struct partition), GFP_KERNEL);
770 if (!part)
771 return;
773 part->mbd.mtd = mtd;
775 if (block_size)
776 part->block_size = block_size;
777 else {
778 if (!mtd->erasesize) {
779 printk(KERN_WARNING PREFIX "please provide block_size");
780 goto out;
781 } else
782 part->block_size = mtd->erasesize;
785 if (scan_header(part) == 0) {
786 part->mbd.size = part->sector_count;
787 part->mbd.tr = tr;
788 part->mbd.devnum = -1;
789 if (!(mtd->flags & MTD_WRITEABLE))
790 part->mbd.readonly = 1;
791 else if (part->errors) {
792 printk(KERN_WARNING PREFIX "'%s': errors found, "
793 "setting read-only\n", mtd->name);
794 part->mbd.readonly = 1;
797 printk(KERN_INFO PREFIX "name: '%s' type: %d flags %x\n",
798 mtd->name, mtd->type, mtd->flags);
800 if (!add_mtd_blktrans_dev((void*)part))
801 return;
803 out:
804 kfree(part);
807 static void rfd_ftl_remove_dev(struct mtd_blktrans_dev *dev)
809 struct partition *part = (struct partition*)dev;
810 int i;
812 for (i=0; i<part->total_blocks; i++) {
813 pr_debug("rfd_ftl_remove_dev:'%s': erase unit #%02d: %d erases\n",
814 part->mbd.mtd->name, i, part->blocks[i].erases);
817 del_mtd_blktrans_dev(dev);
818 vfree(part->sector_map);
819 kfree(part->header_cache);
820 kfree(part->blocks);
821 kfree(part);
824 static struct mtd_blktrans_ops rfd_ftl_tr = {
825 .name = "rfd",
826 .major = RFD_FTL_MAJOR,
827 .part_bits = PART_BITS,
828 .blksize = SECTOR_SIZE,
830 .readsect = rfd_ftl_readsect,
831 .writesect = rfd_ftl_writesect,
832 .getgeo = rfd_ftl_getgeo,
833 .add_mtd = rfd_ftl_add_mtd,
834 .remove_dev = rfd_ftl_remove_dev,
835 .owner = THIS_MODULE,
838 static int __init init_rfd_ftl(void)
840 return register_mtd_blktrans(&rfd_ftl_tr);
843 static void __exit cleanup_rfd_ftl(void)
845 deregister_mtd_blktrans(&rfd_ftl_tr);
848 module_init(init_rfd_ftl);
849 module_exit(cleanup_rfd_ftl);
851 MODULE_LICENSE("GPL");
852 MODULE_AUTHOR("Sean Young <sean@mess.org>");
853 MODULE_DESCRIPTION("Support code for RFD Flash Translation Layer, "
854 "used by General Software's Embedded BIOS");