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
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 static int block_size = 0;
25 module_param(block_size, int, 0);
26 MODULE_PARM_DESC(block_size, "Block size to use by RFD, defaults to erase unit size");
28 #define PREFIX "rfd_ftl: "
30 /* This major has been assigned by device@lanana.org */
32 #define RFD_FTL_MAJOR 256
35 /* Maximum number of partitions in an FTL region */
38 /* An erase unit should start with this value */
39 #define RFD_MAGIC 0x9193
41 /* the second value is 0xffff or 0xffc8; function unknown */
43 /* the third value is always 0xffff, ignored */
45 /* next is an array of mapping for each corresponding sector */
46 #define HEADER_MAP_OFFSET 3
47 #define SECTOR_DELETED 0x0000
48 #define SECTOR_ZERO 0xfffe
49 #define SECTOR_FREE 0xffff
51 #define SECTOR_SIZE 512
53 #define SECTORS_PER_TRACK 63
70 struct mtd_blktrans_dev mbd;
72 u_int block_size; /* size of erase unit */
73 u_int total_blocks; /* number of erase units */
74 u_int header_sectors_per_block; /* header sectors in erase unit */
75 u_int data_sectors_per_block; /* data sectors in erase unit */
76 u_int sector_count; /* sectors in translated disk */
77 u_int header_size; /* bytes in header sector */
78 int reserved_block; /* block next up for reclaim */
79 int current_block; /* block to write to */
80 u16 *header_cache; /* cached header */
89 static int rfd_ftl_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf);
91 static int build_block_map(struct partition *part, int block_no)
93 struct block *block = &part->blocks[block_no];
96 block->offset = part->block_size * block_no;
98 if (le16_to_cpu(part->header_cache[0]) != RFD_MAGIC) {
99 block->state = BLOCK_UNUSED;
103 block->state = BLOCK_OK;
105 for (i=0; i<part->data_sectors_per_block; i++) {
108 entry = le16_to_cpu(part->header_cache[HEADER_MAP_OFFSET + i]);
110 if (entry == SECTOR_DELETED)
113 if (entry == SECTOR_FREE) {
114 block->free_sectors++;
118 if (entry == SECTOR_ZERO)
121 if (entry >= part->sector_count) {
122 printk(KERN_WARNING PREFIX
123 "'%s': unit #%d: entry %d corrupt, "
124 "sector %d out of range\n",
125 part->mbd.mtd->name, block_no, i, entry);
129 if (part->sector_map[entry] != -1) {
130 printk(KERN_WARNING PREFIX
131 "'%s': more than one entry for sector %d\n",
132 part->mbd.mtd->name, entry);
137 part->sector_map[entry] = block->offset +
138 (i + part->header_sectors_per_block) * SECTOR_SIZE;
140 block->used_sectors++;
143 if (block->free_sectors == part->data_sectors_per_block)
144 part->reserved_block = block_no;
149 static int scan_header(struct partition *part)
151 int sectors_per_block;
156 sectors_per_block = part->block_size / SECTOR_SIZE;
157 part->total_blocks = (u32)part->mbd.mtd->size / part->block_size;
159 if (part->total_blocks < 2)
162 /* each erase block has three bytes header, followed by the map */
163 part->header_sectors_per_block =
164 ((HEADER_MAP_OFFSET + sectors_per_block) *
165 sizeof(u16) + SECTOR_SIZE - 1) / SECTOR_SIZE;
167 part->data_sectors_per_block = sectors_per_block -
168 part->header_sectors_per_block;
170 part->header_size = (HEADER_MAP_OFFSET +
171 part->data_sectors_per_block) * sizeof(u16);
173 part->cylinders = (part->data_sectors_per_block *
174 (part->total_blocks - 1) - 1) / SECTORS_PER_TRACK;
176 part->sector_count = part->cylinders * SECTORS_PER_TRACK;
178 part->current_block = -1;
179 part->reserved_block = -1;
180 part->is_reclaiming = 0;
182 part->header_cache = kmalloc(part->header_size, GFP_KERNEL);
183 if (!part->header_cache)
186 part->blocks = kcalloc(part->total_blocks, sizeof(struct block),
191 part->sector_map = vmalloc(part->sector_count * sizeof(u_long));
192 if (!part->sector_map) {
193 printk(KERN_ERR PREFIX "'%s': unable to allocate memory for "
194 "sector map", part->mbd.mtd->name);
198 for (i=0; i<part->sector_count; i++)
199 part->sector_map[i] = -1;
201 for (i=0, blocks_found=0; i<part->total_blocks; i++) {
202 rc = part->mbd.mtd->read(part->mbd.mtd,
203 i * part->block_size, part->header_size,
204 &retlen, (u_char*)part->header_cache);
206 if (!rc && retlen != part->header_size)
212 if (!build_block_map(part, i))
216 if (blocks_found == 0) {
217 printk(KERN_NOTICE PREFIX "no RFD magic found in '%s'\n",
218 part->mbd.mtd->name);
223 if (part->reserved_block == -1) {
224 printk(KERN_WARNING PREFIX "'%s': no empty erase unit found\n",
225 part->mbd.mtd->name);
233 vfree(part->sector_map);
234 kfree(part->header_cache);
240 static int rfd_ftl_readsect(struct mtd_blktrans_dev *dev, u_long sector, char *buf)
242 struct partition *part = (struct partition*)dev;
247 if (sector >= part->sector_count)
250 addr = part->sector_map[sector];
252 rc = part->mbd.mtd->read(part->mbd.mtd, addr, SECTOR_SIZE,
253 &retlen, (u_char*)buf);
254 if (!rc && retlen != SECTOR_SIZE)
258 printk(KERN_WARNING PREFIX "error reading '%s' at "
259 "0x%lx\n", part->mbd.mtd->name, addr);
263 memset(buf, 0, SECTOR_SIZE);
268 static void erase_callback(struct erase_info *erase)
270 struct partition *part;
275 part = (struct partition*)erase->priv;
277 i = (u32)erase->addr / part->block_size;
278 if (i >= part->total_blocks || part->blocks[i].offset != erase->addr ||
279 erase->addr > UINT_MAX) {
280 printk(KERN_ERR PREFIX "erase callback for unknown offset %llx "
281 "on '%s'\n", (unsigned long long)erase->addr, part->mbd.mtd->name);
285 if (erase->state != MTD_ERASE_DONE) {
286 printk(KERN_WARNING PREFIX "erase failed at 0x%llx on '%s', "
287 "state %d\n", (unsigned long long)erase->addr,
288 part->mbd.mtd->name, erase->state);
290 part->blocks[i].state = BLOCK_FAILED;
291 part->blocks[i].free_sectors = 0;
292 part->blocks[i].used_sectors = 0;
299 magic = cpu_to_le16(RFD_MAGIC);
301 part->blocks[i].state = BLOCK_ERASED;
302 part->blocks[i].free_sectors = part->data_sectors_per_block;
303 part->blocks[i].used_sectors = 0;
304 part->blocks[i].erases++;
306 rc = part->mbd.mtd->write(part->mbd.mtd,
307 part->blocks[i].offset, sizeof(magic), &retlen,
310 if (!rc && retlen != sizeof(magic))
314 printk(KERN_ERR PREFIX "'%s': unable to write RFD "
317 part->blocks[i].offset);
318 part->blocks[i].state = BLOCK_FAILED;
321 part->blocks[i].state = BLOCK_OK;
326 static int erase_block(struct partition *part, int block)
328 struct erase_info *erase;
331 erase = kmalloc(sizeof(struct erase_info), GFP_KERNEL);
335 erase->mtd = part->mbd.mtd;
336 erase->callback = erase_callback;
337 erase->addr = part->blocks[block].offset;
338 erase->len = part->block_size;
339 erase->priv = (u_long)part;
341 part->blocks[block].state = BLOCK_ERASING;
342 part->blocks[block].free_sectors = 0;
344 rc = part->mbd.mtd->erase(part->mbd.mtd, erase);
347 printk(KERN_ERR PREFIX "erase of region %llx,%llx on '%s' "
348 "failed\n", (unsigned long long)erase->addr,
349 (unsigned long long)erase->len, part->mbd.mtd->name);
357 static int move_block_contents(struct partition *part, int block_no, u_long *old_sector)
364 part->is_reclaiming = 1;
366 sector_data = kmalloc(SECTOR_SIZE, GFP_KERNEL);
370 map = kmalloc(part->header_size, GFP_KERNEL);
374 rc = part->mbd.mtd->read(part->mbd.mtd,
375 part->blocks[block_no].offset, part->header_size,
376 &retlen, (u_char*)map);
378 if (!rc && retlen != part->header_size)
382 printk(KERN_ERR PREFIX "error reading '%s' at "
383 "0x%lx\n", part->mbd.mtd->name,
384 part->blocks[block_no].offset);
389 for (i=0; i<part->data_sectors_per_block; i++) {
390 u16 entry = le16_to_cpu(map[HEADER_MAP_OFFSET + i]);
394 if (entry == SECTOR_FREE || entry == SECTOR_DELETED)
397 if (entry == SECTOR_ZERO)
400 /* already warned about and ignored in build_block_map() */
401 if (entry >= part->sector_count)
404 addr = part->blocks[block_no].offset +
405 (i + part->header_sectors_per_block) * SECTOR_SIZE;
407 if (*old_sector == addr) {
409 if (!part->blocks[block_no].used_sectors--) {
410 rc = erase_block(part, block_no);
415 rc = part->mbd.mtd->read(part->mbd.mtd, addr,
416 SECTOR_SIZE, &retlen, sector_data);
418 if (!rc && retlen != SECTOR_SIZE)
422 printk(KERN_ERR PREFIX "'%s': Unable to "
423 "read sector for relocation\n",
424 part->mbd.mtd->name);
429 rc = rfd_ftl_writesect((struct mtd_blktrans_dev*)part,
441 part->is_reclaiming = 0;
446 static int reclaim_block(struct partition *part, u_long *old_sector)
448 int block, best_block, score, old_sector_block;
451 /* we have a race if sync doesn't exist */
452 if (part->mbd.mtd->sync)
453 part->mbd.mtd->sync(part->mbd.mtd);
455 score = 0x7fffffff; /* MAX_INT */
457 if (*old_sector != -1)
458 old_sector_block = *old_sector / part->block_size;
460 old_sector_block = -1;
462 for (block=0; block<part->total_blocks; block++) {
465 if (block == part->reserved_block)
469 * Postpone reclaiming if there is a free sector as
470 * more removed sectors is more efficient (have to move
473 if (part->blocks[block].free_sectors)
476 this_score = part->blocks[block].used_sectors;
478 if (block == old_sector_block)
481 /* no point in moving a full block */
482 if (part->blocks[block].used_sectors ==
483 part->data_sectors_per_block)
487 this_score += part->blocks[block].erases;
489 if (this_score < score) {
495 if (best_block == -1)
498 part->current_block = -1;
499 part->reserved_block = best_block;
501 pr_debug("reclaim_block: reclaiming block #%d with %d used "
502 "%d free sectors\n", best_block,
503 part->blocks[best_block].used_sectors,
504 part->blocks[best_block].free_sectors);
506 if (part->blocks[best_block].used_sectors)
507 rc = move_block_contents(part, best_block, old_sector);
509 rc = erase_block(part, best_block);
515 * IMPROVE: It would be best to choose the block with the most deleted sectors,
516 * because if we fill that one up first it'll have the most chance of having
517 * the least live sectors at reclaim.
519 static int find_free_block(struct partition *part)
523 block = part->current_block == -1 ?
524 jiffies % part->total_blocks : part->current_block;
528 if (part->blocks[block].free_sectors &&
529 block != part->reserved_block)
532 if (part->blocks[block].state == BLOCK_UNUSED)
533 erase_block(part, block);
535 if (++block >= part->total_blocks)
538 } while (block != stop);
543 static int find_writable_block(struct partition *part, u_long *old_sector)
548 block = find_free_block(part);
551 if (!part->is_reclaiming) {
552 rc = reclaim_block(part, old_sector);
556 block = find_free_block(part);
565 rc = part->mbd.mtd->read(part->mbd.mtd, part->blocks[block].offset,
566 part->header_size, &retlen, (u_char*)part->header_cache);
568 if (!rc && retlen != part->header_size)
572 printk(KERN_ERR PREFIX "'%s': unable to read header at "
573 "0x%lx\n", part->mbd.mtd->name,
574 part->blocks[block].offset);
578 part->current_block = block;
584 static int mark_sector_deleted(struct partition *part, u_long old_addr)
586 int block, offset, rc;
589 u16 del = cpu_to_le16(SECTOR_DELETED);
591 block = old_addr / part->block_size;
592 offset = (old_addr % part->block_size) / SECTOR_SIZE -
593 part->header_sectors_per_block;
595 addr = part->blocks[block].offset +
596 (HEADER_MAP_OFFSET + offset) * sizeof(u16);
597 rc = part->mbd.mtd->write(part->mbd.mtd, addr,
598 sizeof(del), &retlen, (u_char*)&del);
600 if (!rc && retlen != sizeof(del))
604 printk(KERN_ERR PREFIX "error writing '%s' at "
605 "0x%lx\n", part->mbd.mtd->name, addr);
609 if (block == part->current_block)
610 part->header_cache[offset + HEADER_MAP_OFFSET] = del;
612 part->blocks[block].used_sectors--;
614 if (!part->blocks[block].used_sectors &&
615 !part->blocks[block].free_sectors)
616 rc = erase_block(part, block);
622 static int find_free_sector(const struct partition *part, const struct block *block)
626 i = stop = part->data_sectors_per_block - block->free_sectors;
629 if (le16_to_cpu(part->header_cache[HEADER_MAP_OFFSET + i])
633 if (++i == part->data_sectors_per_block)
641 static int do_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf, ulong *old_addr)
643 struct partition *part = (struct partition*)dev;
651 if (part->current_block == -1 ||
652 !part->blocks[part->current_block].free_sectors) {
654 rc = find_writable_block(part, old_addr);
659 block = &part->blocks[part->current_block];
661 i = find_free_sector(part, block);
668 addr = (i + part->header_sectors_per_block) * SECTOR_SIZE +
670 rc = part->mbd.mtd->write(part->mbd.mtd,
671 addr, SECTOR_SIZE, &retlen, (u_char*)buf);
673 if (!rc && retlen != SECTOR_SIZE)
677 printk(KERN_ERR PREFIX "error writing '%s' at 0x%lx\n",
678 part->mbd.mtd->name, addr);
683 part->sector_map[sector] = addr;
685 entry = cpu_to_le16(sector == 0 ? SECTOR_ZERO : sector);
687 part->header_cache[i + HEADER_MAP_OFFSET] = entry;
689 addr = block->offset + (HEADER_MAP_OFFSET + i) * sizeof(u16);
690 rc = part->mbd.mtd->write(part->mbd.mtd, addr,
691 sizeof(entry), &retlen, (u_char*)&entry);
693 if (!rc && retlen != sizeof(entry))
697 printk(KERN_ERR PREFIX "error writing '%s' at 0x%lx\n",
698 part->mbd.mtd->name, addr);
702 block->used_sectors++;
703 block->free_sectors--;
709 static int rfd_ftl_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf)
711 struct partition *part = (struct partition*)dev;
716 pr_debug("rfd_ftl_writesect(sector=0x%lx)\n", sector);
718 if (part->reserved_block == -1) {
723 if (sector >= part->sector_count) {
728 old_addr = part->sector_map[sector];
730 for (i=0; i<SECTOR_SIZE; i++) {
734 rc = do_writesect(dev, sector, buf, &old_addr);
740 if (i == SECTOR_SIZE)
741 part->sector_map[sector] = -1;
744 rc = mark_sector_deleted(part, old_addr);
750 static int rfd_ftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
752 struct partition *part = (struct partition*)dev;
755 geo->sectors = SECTORS_PER_TRACK;
756 geo->cylinders = part->cylinders;
761 static void rfd_ftl_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
763 struct partition *part;
765 if (mtd->type != MTD_NORFLASH || mtd->size > UINT_MAX)
768 part = kzalloc(sizeof(struct partition), GFP_KERNEL);
775 part->block_size = block_size;
777 if (!mtd->erasesize) {
778 printk(KERN_WARNING PREFIX "please provide block_size");
781 part->block_size = mtd->erasesize;
784 if (scan_header(part) == 0) {
785 part->mbd.size = part->sector_count;
787 part->mbd.devnum = -1;
788 if (!(mtd->flags & MTD_WRITEABLE))
789 part->mbd.readonly = 1;
790 else if (part->errors) {
791 printk(KERN_WARNING PREFIX "'%s': errors found, "
792 "setting read-only\n", mtd->name);
793 part->mbd.readonly = 1;
796 printk(KERN_INFO PREFIX "name: '%s' type: %d flags %x\n",
797 mtd->name, mtd->type, mtd->flags);
799 if (!add_mtd_blktrans_dev((void*)part))
806 static void rfd_ftl_remove_dev(struct mtd_blktrans_dev *dev)
808 struct partition *part = (struct partition*)dev;
811 for (i=0; i<part->total_blocks; i++) {
812 pr_debug("rfd_ftl_remove_dev:'%s': erase unit #%02d: %d erases\n",
813 part->mbd.mtd->name, i, part->blocks[i].erases);
816 del_mtd_blktrans_dev(dev);
817 vfree(part->sector_map);
818 kfree(part->header_cache);
823 static struct mtd_blktrans_ops rfd_ftl_tr = {
825 .major = RFD_FTL_MAJOR,
826 .part_bits = PART_BITS,
827 .blksize = SECTOR_SIZE,
829 .readsect = rfd_ftl_readsect,
830 .writesect = rfd_ftl_writesect,
831 .getgeo = rfd_ftl_getgeo,
832 .add_mtd = rfd_ftl_add_mtd,
833 .remove_dev = rfd_ftl_remove_dev,
834 .owner = THIS_MODULE,
837 static int __init init_rfd_ftl(void)
839 return register_mtd_blktrans(&rfd_ftl_tr);
842 static void __exit cleanup_rfd_ftl(void)
844 deregister_mtd_blktrans(&rfd_ftl_tr);
847 module_init(init_rfd_ftl);
848 module_exit(cleanup_rfd_ftl);
850 MODULE_LICENSE("GPL");
851 MODULE_AUTHOR("Sean Young <sean@mess.org>");
852 MODULE_DESCRIPTION("Support code for RFD Flash Translation Layer, "
853 "used by General Software's Embedded BIOS");