2 * rfd_ftl.c -- resident flash disk (flash translation layer)
4 * Copyright © 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>
21 #include <linux/module.h>
23 #include <asm/types.h>
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");
29 #define PREFIX "rfd_ftl: "
31 /* This major has been assigned by device@lanana.org */
33 #define RFD_FTL_MAJOR 256
36 /* Maximum number of partitions in an FTL region */
39 /* An erase unit should start with this value */
40 #define RFD_MAGIC 0x9193
42 /* the second value is 0xffff or 0xffc8; function unknown */
44 /* the third value is always 0xffff, ignored */
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
52 #define SECTOR_SIZE 512
54 #define SECTORS_PER_TRACK 63
71 struct mtd_blktrans_dev mbd;
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 */
90 static int rfd_ftl_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf);
92 static int build_block_map(struct partition *part, int block_no)
94 struct block *block = &part->blocks[block_no];
97 block->offset = part->block_size * block_no;
99 if (le16_to_cpu(part->header_cache[0]) != RFD_MAGIC) {
100 block->state = BLOCK_UNUSED;
104 block->state = BLOCK_OK;
106 for (i=0; i<part->data_sectors_per_block; i++) {
109 entry = le16_to_cpu(part->header_cache[HEADER_MAP_OFFSET + i]);
111 if (entry == SECTOR_DELETED)
114 if (entry == SECTOR_FREE) {
115 block->free_sectors++;
119 if (entry == SECTOR_ZERO)
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);
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);
138 part->sector_map[entry] = block->offset +
139 (i + part->header_sectors_per_block) * SECTOR_SIZE;
141 block->used_sectors++;
144 if (block->free_sectors == part->data_sectors_per_block)
145 part->reserved_block = block_no;
150 static int scan_header(struct partition *part)
152 int sectors_per_block;
157 sectors_per_block = part->block_size / SECTOR_SIZE;
158 part->total_blocks = (u32)part->mbd.mtd->size / part->block_size;
160 if (part->total_blocks < 2)
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;
168 part->data_sectors_per_block = sectors_per_block -
169 part->header_sectors_per_block;
171 part->header_size = (HEADER_MAP_OFFSET +
172 part->data_sectors_per_block) * sizeof(u16);
174 part->cylinders = (part->data_sectors_per_block *
175 (part->total_blocks - 1) - 1) / SECTORS_PER_TRACK;
177 part->sector_count = part->cylinders * SECTORS_PER_TRACK;
179 part->current_block = -1;
180 part->reserved_block = -1;
181 part->is_reclaiming = 0;
183 part->header_cache = kmalloc(part->header_size, GFP_KERNEL);
184 if (!part->header_cache)
187 part->blocks = kcalloc(part->total_blocks, sizeof(struct block),
192 part->sector_map = vmalloc(part->sector_count * sizeof(u_long));
193 if (!part->sector_map) {
194 printk(KERN_ERR PREFIX "'%s': unable to allocate memory for "
195 "sector map", part->mbd.mtd->name);
199 for (i=0; i<part->sector_count; i++)
200 part->sector_map[i] = -1;
202 for (i=0, blocks_found=0; i<part->total_blocks; i++) {
203 rc = mtd_read(part->mbd.mtd, i * part->block_size,
204 part->header_size, &retlen,
205 (u_char *)part->header_cache);
207 if (!rc && retlen != part->header_size)
213 if (!build_block_map(part, i))
217 if (blocks_found == 0) {
218 printk(KERN_NOTICE PREFIX "no RFD magic found in '%s'\n",
219 part->mbd.mtd->name);
224 if (part->reserved_block == -1) {
225 printk(KERN_WARNING PREFIX "'%s': no empty erase unit found\n",
226 part->mbd.mtd->name);
234 vfree(part->sector_map);
235 kfree(part->header_cache);
241 static int rfd_ftl_readsect(struct mtd_blktrans_dev *dev, u_long sector, char *buf)
243 struct partition *part = (struct partition*)dev;
248 if (sector >= part->sector_count)
251 addr = part->sector_map[sector];
253 rc = mtd_read(part->mbd.mtd, addr, SECTOR_SIZE, &retlen,
255 if (!rc && retlen != SECTOR_SIZE)
259 printk(KERN_WARNING PREFIX "error reading '%s' at "
260 "0x%lx\n", part->mbd.mtd->name, addr);
264 memset(buf, 0, SECTOR_SIZE);
269 static void erase_callback(struct erase_info *erase)
271 struct partition *part;
276 part = (struct partition*)erase->priv;
278 i = (u32)erase->addr / part->block_size;
279 if (i >= part->total_blocks || part->blocks[i].offset != erase->addr ||
280 erase->addr > UINT_MAX) {
281 printk(KERN_ERR PREFIX "erase callback for unknown offset %llx "
282 "on '%s'\n", (unsigned long long)erase->addr, part->mbd.mtd->name);
286 if (erase->state != MTD_ERASE_DONE) {
287 printk(KERN_WARNING PREFIX "erase failed at 0x%llx on '%s', "
288 "state %d\n", (unsigned long long)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;
300 magic = 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 = mtd_write(part->mbd.mtd, part->blocks[i].offset, sizeof(magic),
308 &retlen, (u_char *)&magic);
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 = 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 = mtd_read(part->mbd.mtd, part->blocks[block_no].offset,
375 part->header_size, &retlen, (u_char *)map);
377 if (!rc && retlen != part->header_size)
381 printk(KERN_ERR PREFIX "error reading '%s' at "
382 "0x%lx\n", part->mbd.mtd->name,
383 part->blocks[block_no].offset);
388 for (i=0; i<part->data_sectors_per_block; i++) {
389 u16 entry = le16_to_cpu(map[HEADER_MAP_OFFSET + i]);
393 if (entry == SECTOR_FREE || entry == SECTOR_DELETED)
396 if (entry == SECTOR_ZERO)
399 /* already warned about and ignored in build_block_map() */
400 if (entry >= part->sector_count)
403 addr = part->blocks[block_no].offset +
404 (i + part->header_sectors_per_block) * SECTOR_SIZE;
406 if (*old_sector == addr) {
408 if (!part->blocks[block_no].used_sectors--) {
409 rc = erase_block(part, block_no);
414 rc = mtd_read(part->mbd.mtd, addr, SECTOR_SIZE, &retlen,
417 if (!rc && retlen != SECTOR_SIZE)
421 printk(KERN_ERR PREFIX "'%s': Unable to "
422 "read sector for relocation\n",
423 part->mbd.mtd->name);
428 rc = rfd_ftl_writesect((struct mtd_blktrans_dev*)part,
440 part->is_reclaiming = 0;
445 static int reclaim_block(struct partition *part, u_long *old_sector)
447 int block, best_block, score, old_sector_block;
450 /* we have a race if sync doesn't exist */
451 if (part->mbd.mtd->sync)
452 mtd_sync(part->mbd.mtd);
454 score = 0x7fffffff; /* MAX_INT */
456 if (*old_sector != -1)
457 old_sector_block = *old_sector / part->block_size;
459 old_sector_block = -1;
461 for (block=0; block<part->total_blocks; block++) {
464 if (block == part->reserved_block)
468 * Postpone reclaiming if there is a free sector as
469 * more removed sectors is more efficient (have to move
472 if (part->blocks[block].free_sectors)
475 this_score = part->blocks[block].used_sectors;
477 if (block == old_sector_block)
480 /* no point in moving a full block */
481 if (part->blocks[block].used_sectors ==
482 part->data_sectors_per_block)
486 this_score += part->blocks[block].erases;
488 if (this_score < score) {
494 if (best_block == -1)
497 part->current_block = -1;
498 part->reserved_block = best_block;
500 pr_debug("reclaim_block: reclaiming block #%d with %d used "
501 "%d free sectors\n", best_block,
502 part->blocks[best_block].used_sectors,
503 part->blocks[best_block].free_sectors);
505 if (part->blocks[best_block].used_sectors)
506 rc = move_block_contents(part, best_block, old_sector);
508 rc = erase_block(part, best_block);
514 * IMPROVE: It would be best to choose the block with the most deleted sectors,
515 * because if we fill that one up first it'll have the most chance of having
516 * the least live sectors at reclaim.
518 static int find_free_block(struct partition *part)
522 block = part->current_block == -1 ?
523 jiffies % part->total_blocks : part->current_block;
527 if (part->blocks[block].free_sectors &&
528 block != part->reserved_block)
531 if (part->blocks[block].state == BLOCK_UNUSED)
532 erase_block(part, block);
534 if (++block >= part->total_blocks)
537 } while (block != stop);
542 static int find_writable_block(struct partition *part, u_long *old_sector)
547 block = find_free_block(part);
550 if (!part->is_reclaiming) {
551 rc = reclaim_block(part, old_sector);
555 block = find_free_block(part);
564 rc = mtd_read(part->mbd.mtd, part->blocks[block].offset,
565 part->header_size, &retlen,
566 (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 = mtd_write(part->mbd.mtd, addr, sizeof(del), &retlen,
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 = mtd_write(part->mbd.mtd, addr, SECTOR_SIZE, &retlen,
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 = mtd_write(part->mbd.mtd, addr, sizeof(entry), &retlen,
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);
822 static struct mtd_blktrans_ops rfd_ftl_tr = {
824 .major = RFD_FTL_MAJOR,
825 .part_bits = PART_BITS,
826 .blksize = SECTOR_SIZE,
828 .readsect = rfd_ftl_readsect,
829 .writesect = rfd_ftl_writesect,
830 .getgeo = rfd_ftl_getgeo,
831 .add_mtd = rfd_ftl_add_mtd,
832 .remove_dev = rfd_ftl_remove_dev,
833 .owner = THIS_MODULE,
836 static int __init init_rfd_ftl(void)
838 return register_mtd_blktrans(&rfd_ftl_tr);
841 static void __exit cleanup_rfd_ftl(void)
843 deregister_mtd_blktrans(&rfd_ftl_tr);
846 module_init(init_rfd_ftl);
847 module_exit(cleanup_rfd_ftl);
849 MODULE_LICENSE("GPL");
850 MODULE_AUTHOR("Sean Young <sean@mess.org>");
851 MODULE_DESCRIPTION("Support code for RFD Flash Translation Layer, "
852 "used by General Software's Embedded BIOS");