[PATCH] Remove useless comment from sb1250
[linux-2.6/linux-2.6-openrd.git] / drivers / mtd / rfd_ftl.c
blobfa4362fb4dd8a2b7260b75ae66c0866dcb472233
1 /*
2 * rfd_ftl.c -- resident flash disk (flash translation layer)
4 * Copyright (C) 2005 Sean Young <sean@mess.org>
6 * $Id: rfd_ftl.c,v 1.8 2006/01/15 12:51:44 sean Exp $
8 * This type of flash translation layer (FTL) is used by the Embedded BIOS
9 * by General Software. It is known as the Resident Flash Disk (RFD), see:
11 * http://www.gensw.com/pages/prod/bios/rfd.htm
13 * based on ftl.c
16 #include <linux/hdreg.h>
17 #include <linux/init.h>
18 #include <linux/mtd/blktrans.h>
19 #include <linux/mtd/mtd.h>
20 #include <linux/vmalloc.h>
21 #include <linux/slab.h>
22 #include <linux/jiffies.h>
24 #include <asm/types.h>
26 #define const_cpu_to_le16 __constant_cpu_to_le16
28 static int block_size = 0;
29 module_param(block_size, int, 0);
30 MODULE_PARM_DESC(block_size, "Block size to use by RFD, defaults to erase unit size");
32 #define PREFIX "rfd_ftl: "
34 /* This major has been assigned by device@lanana.org */
35 #ifndef RFD_FTL_MAJOR
36 #define RFD_FTL_MAJOR 256
37 #endif
39 /* Maximum number of partitions in an FTL region */
40 #define PART_BITS 4
42 /* An erase unit should start with this value */
43 #define RFD_MAGIC 0x9193
45 /* the second value is 0xffff or 0xffc8; function unknown */
47 /* the third value is always 0xffff, ignored */
49 /* next is an array of mapping for each corresponding sector */
50 #define HEADER_MAP_OFFSET 3
51 #define SECTOR_DELETED 0x0000
52 #define SECTOR_ZERO 0xfffe
53 #define SECTOR_FREE 0xffff
55 #define SECTOR_SIZE 512
57 #define SECTORS_PER_TRACK 63
59 struct block {
60 enum {
61 BLOCK_OK,
62 BLOCK_ERASING,
63 BLOCK_ERASED,
64 BLOCK_UNUSED,
65 BLOCK_FAILED
66 } state;
67 int free_sectors;
68 int used_sectors;
69 int erases;
70 u_long offset;
73 struct partition {
74 struct mtd_blktrans_dev mbd;
76 u_int block_size; /* size of erase unit */
77 u_int total_blocks; /* number of erase units */
78 u_int header_sectors_per_block; /* header sectors in erase unit */
79 u_int data_sectors_per_block; /* data sectors in erase unit */
80 u_int sector_count; /* sectors in translated disk */
81 u_int header_size; /* bytes in header sector */
82 int reserved_block; /* block next up for reclaim */
83 int current_block; /* block to write to */
84 u16 *header_cache; /* cached header */
86 int is_reclaiming;
87 int cylinders;
88 int errors;
89 u_long *sector_map;
90 struct block *blocks;
93 static int rfd_ftl_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf);
95 static int build_block_map(struct partition *part, int block_no)
97 struct block *block = &part->blocks[block_no];
98 int i;
100 block->offset = part->block_size * block_no;
102 if (le16_to_cpu(part->header_cache[0]) != RFD_MAGIC) {
103 block->state = BLOCK_UNUSED;
104 return -ENOENT;
107 block->state = BLOCK_OK;
109 for (i=0; i<part->data_sectors_per_block; i++) {
110 u16 entry;
112 entry = le16_to_cpu(part->header_cache[HEADER_MAP_OFFSET + i]);
114 if (entry == SECTOR_DELETED)
115 continue;
117 if (entry == SECTOR_FREE) {
118 block->free_sectors++;
119 continue;
122 if (entry == SECTOR_ZERO)
123 entry = 0;
125 if (entry >= part->sector_count) {
126 printk(KERN_WARNING PREFIX
127 "'%s': unit #%d: entry %d corrupt, "
128 "sector %d out of range\n",
129 part->mbd.mtd->name, block_no, i, entry);
130 continue;
133 if (part->sector_map[entry] != -1) {
134 printk(KERN_WARNING PREFIX
135 "'%s': more than one entry for sector %d\n",
136 part->mbd.mtd->name, entry);
137 part->errors = 1;
138 continue;
141 part->sector_map[entry] = block->offset +
142 (i + part->header_sectors_per_block) * SECTOR_SIZE;
144 block->used_sectors++;
147 if (block->free_sectors == part->data_sectors_per_block)
148 part->reserved_block = block_no;
150 return 0;
153 static int scan_header(struct partition *part)
155 int sectors_per_block;
156 int i, rc = -ENOMEM;
157 int blocks_found;
158 size_t retlen;
160 sectors_per_block = part->block_size / SECTOR_SIZE;
161 part->total_blocks = part->mbd.mtd->size / part->block_size;
163 if (part->total_blocks < 2)
164 return -ENOENT;
166 /* each erase block has three bytes header, followed by the map */
167 part->header_sectors_per_block =
168 ((HEADER_MAP_OFFSET + sectors_per_block) *
169 sizeof(u16) + SECTOR_SIZE - 1) / SECTOR_SIZE;
171 part->data_sectors_per_block = sectors_per_block -
172 part->header_sectors_per_block;
174 part->header_size = (HEADER_MAP_OFFSET +
175 part->data_sectors_per_block) * sizeof(u16);
177 part->cylinders = (part->data_sectors_per_block *
178 (part->total_blocks - 1) - 1) / SECTORS_PER_TRACK;
180 part->sector_count = part->cylinders * SECTORS_PER_TRACK;
182 part->current_block = -1;
183 part->reserved_block = -1;
184 part->is_reclaiming = 0;
186 part->header_cache = kmalloc(part->header_size, GFP_KERNEL);
187 if (!part->header_cache)
188 goto err;
190 part->blocks = kcalloc(part->total_blocks, sizeof(struct block),
191 GFP_KERNEL);
192 if (!part->blocks)
193 goto err;
195 part->sector_map = vmalloc(part->sector_count * sizeof(u_long));
196 if (!part->sector_map) {
197 printk(KERN_ERR PREFIX "'%s': unable to allocate memory for "
198 "sector map", part->mbd.mtd->name);
199 goto err;
202 for (i=0; i<part->sector_count; i++)
203 part->sector_map[i] = -1;
205 for (i=0, blocks_found=0; i<part->total_blocks; i++) {
206 rc = part->mbd.mtd->read(part->mbd.mtd,
207 i * part->block_size, part->header_size,
208 &retlen, (u_char*)part->header_cache);
210 if (!rc && retlen != part->header_size)
211 rc = -EIO;
213 if (rc)
214 goto err;
216 if (!build_block_map(part, i))
217 blocks_found++;
220 if (blocks_found == 0) {
221 printk(KERN_NOTICE PREFIX "no RFD magic found in '%s'\n",
222 part->mbd.mtd->name);
223 rc = -ENOENT;
224 goto err;
227 if (part->reserved_block == -1) {
228 printk(KERN_WARNING PREFIX "'%s': no empty erase unit found\n",
229 part->mbd.mtd->name);
231 part->errors = 1;
234 return 0;
236 err:
237 vfree(part->sector_map);
238 kfree(part->header_cache);
239 kfree(part->blocks);
241 return rc;
244 static int rfd_ftl_readsect(struct mtd_blktrans_dev *dev, u_long sector, char *buf)
246 struct partition *part = (struct partition*)dev;
247 u_long addr;
248 size_t retlen;
249 int rc;
251 if (sector >= part->sector_count)
252 return -EIO;
254 addr = part->sector_map[sector];
255 if (addr != -1) {
256 rc = part->mbd.mtd->read(part->mbd.mtd, addr, SECTOR_SIZE,
257 &retlen, (u_char*)buf);
258 if (!rc && retlen != SECTOR_SIZE)
259 rc = -EIO;
261 if (rc) {
262 printk(KERN_WARNING PREFIX "error reading '%s' at "
263 "0x%lx\n", part->mbd.mtd->name, addr);
264 return rc;
266 } else
267 memset(buf, 0, SECTOR_SIZE);
269 return 0;
272 static void erase_callback(struct erase_info *erase)
274 struct partition *part;
275 u16 magic;
276 int i, rc;
277 size_t retlen;
279 part = (struct partition*)erase->priv;
281 i = erase->addr / part->block_size;
282 if (i >= part->total_blocks || part->blocks[i].offset != erase->addr) {
283 printk(KERN_ERR PREFIX "erase callback for unknown offset %x "
284 "on '%s'\n", erase->addr, part->mbd.mtd->name);
285 return;
288 if (erase->state != MTD_ERASE_DONE) {
289 printk(KERN_WARNING PREFIX "erase failed at 0x%x on '%s', "
290 "state %d\n", erase->addr,
291 part->mbd.mtd->name, erase->state);
293 part->blocks[i].state = BLOCK_FAILED;
294 part->blocks[i].free_sectors = 0;
295 part->blocks[i].used_sectors = 0;
297 kfree(erase);
299 return;
302 magic = const_cpu_to_le16(RFD_MAGIC);
304 part->blocks[i].state = BLOCK_ERASED;
305 part->blocks[i].free_sectors = part->data_sectors_per_block;
306 part->blocks[i].used_sectors = 0;
307 part->blocks[i].erases++;
309 rc = part->mbd.mtd->write(part->mbd.mtd,
310 part->blocks[i].offset, sizeof(magic), &retlen,
311 (u_char*)&magic);
313 if (!rc && retlen != sizeof(magic))
314 rc = -EIO;
316 if (rc) {
317 printk(KERN_ERR PREFIX "'%s': unable to write RFD "
318 "header at 0x%lx\n",
319 part->mbd.mtd->name,
320 part->blocks[i].offset);
321 part->blocks[i].state = BLOCK_FAILED;
323 else
324 part->blocks[i].state = BLOCK_OK;
326 kfree(erase);
329 static int erase_block(struct partition *part, int block)
331 struct erase_info *erase;
332 int rc = -ENOMEM;
334 erase = kmalloc(sizeof(struct erase_info), GFP_KERNEL);
335 if (!erase)
336 goto err;
338 erase->mtd = part->mbd.mtd;
339 erase->callback = erase_callback;
340 erase->addr = part->blocks[block].offset;
341 erase->len = part->block_size;
342 erase->priv = (u_long)part;
344 part->blocks[block].state = BLOCK_ERASING;
345 part->blocks[block].free_sectors = 0;
347 rc = part->mbd.mtd->erase(part->mbd.mtd, erase);
349 if (rc) {
350 printk(KERN_ERR PREFIX "erase of region %x,%x on '%s' "
351 "failed\n", erase->addr, erase->len,
352 part->mbd.mtd->name);
353 kfree(erase);
356 err:
357 return rc;
360 static int move_block_contents(struct partition *part, int block_no, u_long *old_sector)
362 void *sector_data;
363 u16 *map;
364 size_t retlen;
365 int i, rc = -ENOMEM;
367 part->is_reclaiming = 1;
369 sector_data = kmalloc(SECTOR_SIZE, GFP_KERNEL);
370 if (!sector_data)
371 goto err3;
373 map = kmalloc(part->header_size, GFP_KERNEL);
374 if (!map)
375 goto err2;
377 rc = part->mbd.mtd->read(part->mbd.mtd,
378 part->blocks[block_no].offset, part->header_size,
379 &retlen, (u_char*)map);
381 if (!rc && retlen != part->header_size)
382 rc = -EIO;
384 if (rc) {
385 printk(KERN_ERR PREFIX "error reading '%s' at "
386 "0x%lx\n", part->mbd.mtd->name,
387 part->blocks[block_no].offset);
389 goto err;
392 for (i=0; i<part->data_sectors_per_block; i++) {
393 u16 entry = le16_to_cpu(map[HEADER_MAP_OFFSET + i]);
394 u_long addr;
397 if (entry == SECTOR_FREE || entry == SECTOR_DELETED)
398 continue;
400 if (entry == SECTOR_ZERO)
401 entry = 0;
403 /* already warned about and ignored in build_block_map() */
404 if (entry >= part->sector_count)
405 continue;
407 addr = part->blocks[block_no].offset +
408 (i + part->header_sectors_per_block) * SECTOR_SIZE;
410 if (*old_sector == addr) {
411 *old_sector = -1;
412 if (!part->blocks[block_no].used_sectors--) {
413 rc = erase_block(part, block_no);
414 break;
416 continue;
418 rc = part->mbd.mtd->read(part->mbd.mtd, addr,
419 SECTOR_SIZE, &retlen, sector_data);
421 if (!rc && retlen != SECTOR_SIZE)
422 rc = -EIO;
424 if (rc) {
425 printk(KERN_ERR PREFIX "'%s': Unable to "
426 "read sector for relocation\n",
427 part->mbd.mtd->name);
429 goto err;
432 rc = rfd_ftl_writesect((struct mtd_blktrans_dev*)part,
433 entry, sector_data);
435 if (rc)
436 goto err;
439 err:
440 kfree(map);
441 err2:
442 kfree(sector_data);
443 err3:
444 part->is_reclaiming = 0;
446 return rc;
449 static int reclaim_block(struct partition *part, u_long *old_sector)
451 int block, best_block, score, old_sector_block;
452 int rc;
454 /* we have a race if sync doesn't exist */
455 if (part->mbd.mtd->sync)
456 part->mbd.mtd->sync(part->mbd.mtd);
458 score = 0x7fffffff; /* MAX_INT */
459 best_block = -1;
460 if (*old_sector != -1)
461 old_sector_block = *old_sector / part->block_size;
462 else
463 old_sector_block = -1;
465 for (block=0; block<part->total_blocks; block++) {
466 int this_score;
468 if (block == part->reserved_block)
469 continue;
472 * Postpone reclaiming if there is a free sector as
473 * more removed sectors is more efficient (have to move
474 * less).
476 if (part->blocks[block].free_sectors)
477 return 0;
479 this_score = part->blocks[block].used_sectors;
481 if (block == old_sector_block)
482 this_score--;
483 else {
484 /* no point in moving a full block */
485 if (part->blocks[block].used_sectors ==
486 part->data_sectors_per_block)
487 continue;
490 this_score += part->blocks[block].erases;
492 if (this_score < score) {
493 best_block = block;
494 score = this_score;
498 if (best_block == -1)
499 return -ENOSPC;
501 part->current_block = -1;
502 part->reserved_block = best_block;
504 pr_debug("reclaim_block: reclaiming block #%d with %d used "
505 "%d free sectors\n", best_block,
506 part->blocks[best_block].used_sectors,
507 part->blocks[best_block].free_sectors);
509 if (part->blocks[best_block].used_sectors)
510 rc = move_block_contents(part, best_block, old_sector);
511 else
512 rc = erase_block(part, best_block);
514 return rc;
518 * IMPROVE: It would be best to choose the block with the most deleted sectors,
519 * because if we fill that one up first it'll have the most chance of having
520 * the least live sectors at reclaim.
522 static int find_free_block(struct partition *part)
524 int block, stop;
526 block = part->current_block == -1 ?
527 jiffies % part->total_blocks : part->current_block;
528 stop = block;
530 do {
531 if (part->blocks[block].free_sectors &&
532 block != part->reserved_block)
533 return block;
535 if (part->blocks[block].state == BLOCK_UNUSED)
536 erase_block(part, block);
538 if (++block >= part->total_blocks)
539 block = 0;
541 } while (block != stop);
543 return -1;
546 static int find_writable_block(struct partition *part, u_long *old_sector)
548 int rc, block;
549 size_t retlen;
551 block = find_free_block(part);
553 if (block == -1) {
554 if (!part->is_reclaiming) {
555 rc = reclaim_block(part, old_sector);
556 if (rc)
557 goto err;
559 block = find_free_block(part);
562 if (block == -1) {
563 rc = -ENOSPC;
564 goto err;
568 rc = part->mbd.mtd->read(part->mbd.mtd, part->blocks[block].offset,
569 part->header_size, &retlen, (u_char*)part->header_cache);
571 if (!rc && retlen != part->header_size)
572 rc = -EIO;
574 if (rc) {
575 printk(KERN_ERR PREFIX "'%s': unable to read header at "
576 "0x%lx\n", part->mbd.mtd->name,
577 part->blocks[block].offset);
578 goto err;
581 part->current_block = block;
583 err:
584 return rc;
587 static int mark_sector_deleted(struct partition *part, u_long old_addr)
589 int block, offset, rc;
590 u_long addr;
591 size_t retlen;
592 u16 del = const_cpu_to_le16(SECTOR_DELETED);
594 block = old_addr / part->block_size;
595 offset = (old_addr % part->block_size) / SECTOR_SIZE -
596 part->header_sectors_per_block;
598 addr = part->blocks[block].offset +
599 (HEADER_MAP_OFFSET + offset) * sizeof(u16);
600 rc = part->mbd.mtd->write(part->mbd.mtd, addr,
601 sizeof(del), &retlen, (u_char*)&del);
603 if (!rc && retlen != sizeof(del))
604 rc = -EIO;
606 if (rc) {
607 printk(KERN_ERR PREFIX "error writing '%s' at "
608 "0x%lx\n", part->mbd.mtd->name, addr);
609 if (rc)
610 goto err;
612 if (block == part->current_block)
613 part->header_cache[offset + HEADER_MAP_OFFSET] = del;
615 part->blocks[block].used_sectors--;
617 if (!part->blocks[block].used_sectors &&
618 !part->blocks[block].free_sectors)
619 rc = erase_block(part, block);
621 err:
622 return rc;
625 static int find_free_sector(const struct partition *part, const struct block *block)
627 int i, stop;
629 i = stop = part->data_sectors_per_block - block->free_sectors;
631 do {
632 if (le16_to_cpu(part->header_cache[HEADER_MAP_OFFSET + i])
633 == SECTOR_FREE)
634 return i;
636 if (++i == part->data_sectors_per_block)
637 i = 0;
639 while(i != stop);
641 return -1;
644 static int do_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf, ulong *old_addr)
646 struct partition *part = (struct partition*)dev;
647 struct block *block;
648 u_long addr;
649 int i;
650 int rc;
651 size_t retlen;
652 u16 entry;
654 if (part->current_block == -1 ||
655 !part->blocks[part->current_block].free_sectors) {
657 rc = find_writable_block(part, old_addr);
658 if (rc)
659 goto err;
662 block = &part->blocks[part->current_block];
664 i = find_free_sector(part, block);
666 if (i < 0) {
667 rc = -ENOSPC;
668 goto err;
671 addr = (i + part->header_sectors_per_block) * SECTOR_SIZE +
672 block->offset;
673 rc = part->mbd.mtd->write(part->mbd.mtd,
674 addr, SECTOR_SIZE, &retlen, (u_char*)buf);
676 if (!rc && retlen != SECTOR_SIZE)
677 rc = -EIO;
679 if (rc) {
680 printk(KERN_ERR PREFIX "error writing '%s' at 0x%lx\n",
681 part->mbd.mtd->name, addr);
682 if (rc)
683 goto err;
686 part->sector_map[sector] = addr;
688 entry = cpu_to_le16(sector == 0 ? SECTOR_ZERO : sector);
690 part->header_cache[i + HEADER_MAP_OFFSET] = entry;
692 addr = block->offset + (HEADER_MAP_OFFSET + i) * sizeof(u16);
693 rc = part->mbd.mtd->write(part->mbd.mtd, addr,
694 sizeof(entry), &retlen, (u_char*)&entry);
696 if (!rc && retlen != sizeof(entry))
697 rc = -EIO;
699 if (rc) {
700 printk(KERN_ERR PREFIX "error writing '%s' at 0x%lx\n",
701 part->mbd.mtd->name, addr);
702 if (rc)
703 goto err;
705 block->used_sectors++;
706 block->free_sectors--;
708 err:
709 return rc;
712 static int rfd_ftl_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf)
714 struct partition *part = (struct partition*)dev;
715 u_long old_addr;
716 int i;
717 int rc = 0;
719 pr_debug("rfd_ftl_writesect(sector=0x%lx)\n", sector);
721 if (part->reserved_block == -1) {
722 rc = -EACCES;
723 goto err;
726 if (sector >= part->sector_count) {
727 rc = -EIO;
728 goto err;
731 old_addr = part->sector_map[sector];
733 for (i=0; i<SECTOR_SIZE; i++) {
734 if (!buf[i])
735 continue;
737 rc = do_writesect(dev, sector, buf, &old_addr);
738 if (rc)
739 goto err;
740 break;
743 if (i == SECTOR_SIZE)
744 part->sector_map[sector] = -1;
746 if (old_addr != -1)
747 rc = mark_sector_deleted(part, old_addr);
749 err:
750 return rc;
753 static int rfd_ftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
755 struct partition *part = (struct partition*)dev;
757 geo->heads = 1;
758 geo->sectors = SECTORS_PER_TRACK;
759 geo->cylinders = part->cylinders;
761 return 0;
764 static void rfd_ftl_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
766 struct partition *part;
768 if (mtd->type != MTD_NORFLASH)
769 return;
771 part = kcalloc(1, sizeof(struct partition), GFP_KERNEL);
772 if (!part)
773 return;
775 part->mbd.mtd = mtd;
777 if (block_size)
778 part->block_size = block_size;
779 else {
780 if (!mtd->erasesize) {
781 printk(KERN_WARNING PREFIX "please provide block_size");
782 return;
784 else
785 part->block_size = mtd->erasesize;
788 if (scan_header(part) == 0) {
789 part->mbd.size = part->sector_count;
790 part->mbd.blksize = SECTOR_SIZE;
791 part->mbd.tr = tr;
792 part->mbd.devnum = -1;
793 if (!(mtd->flags & MTD_WRITEABLE))
794 part->mbd.readonly = 1;
795 else if (part->errors) {
796 printk(KERN_WARNING PREFIX "'%s': errors found, "
797 "setting read-only\n", mtd->name);
798 part->mbd.readonly = 1;
801 printk(KERN_INFO PREFIX "name: '%s' type: %d flags %x\n",
802 mtd->name, mtd->type, mtd->flags);
804 if (!add_mtd_blktrans_dev((void*)part))
805 return;
808 kfree(part);
811 static void rfd_ftl_remove_dev(struct mtd_blktrans_dev *dev)
813 struct partition *part = (struct partition*)dev;
814 int i;
816 for (i=0; i<part->total_blocks; i++) {
817 pr_debug("rfd_ftl_remove_dev:'%s': erase unit #%02d: %d erases\n",
818 part->mbd.mtd->name, i, part->blocks[i].erases);
821 del_mtd_blktrans_dev(dev);
822 vfree(part->sector_map);
823 kfree(part->header_cache);
824 kfree(part->blocks);
825 kfree(part);
828 struct mtd_blktrans_ops rfd_ftl_tr = {
829 .name = "rfd",
830 .major = RFD_FTL_MAJOR,
831 .part_bits = PART_BITS,
832 .readsect = rfd_ftl_readsect,
833 .writesect = rfd_ftl_writesect,
834 .getgeo = rfd_ftl_getgeo,
835 .add_mtd = rfd_ftl_add_mtd,
836 .remove_dev = rfd_ftl_remove_dev,
837 .owner = THIS_MODULE,
840 static int __init init_rfd_ftl(void)
842 return register_mtd_blktrans(&rfd_ftl_tr);
845 static void __exit cleanup_rfd_ftl(void)
847 deregister_mtd_blktrans(&rfd_ftl_tr);
850 module_init(init_rfd_ftl);
851 module_exit(cleanup_rfd_ftl);
853 MODULE_LICENSE("GPL");
854 MODULE_AUTHOR("Sean Young <sean@mess.org>");
855 MODULE_DESCRIPTION("Support code for RFD Flash Translation Layer, "
856 "used by General Software's Embedded BIOS");