// SPDX-License-Identifier: GPL-2.0-only /* * rfd_ftl.c -- resident flash disk (flash translation layer) * * Copyright © 2005 Sean Young <sean@mess.org> * * This type of flash translation layer (FTL) is used by the Embedded BIOS * by General Software. It is known as the Resident Flash Disk (RFD), see: * * http://www.gensw.com/pages/prod/bios/rfd.htm * * based on ftl.c */ #include <linux/hdreg.h> #include <linux/init.h> #include <linux/mtd/blktrans.h> #include <linux/mtd/mtd.h> #include <linux/vmalloc.h> #include <linux/slab.h> #include <linux/jiffies.h> #include <linux/module.h> #include <asm/types.h> static int block_size = 0; module_param(block_size, int, 0); MODULE_PARM_DESC(block_size, "Block size to use by RFD, defaults to erase unit size"); #define PREFIX "rfd_ftl: " /* This major has been assigned by device@lanana.org */ #ifndef RFD_FTL_MAJOR #define RFD_FTL_MAJOR 256 #endif /* Maximum number of partitions in an FTL region */ #define PART_BITS 4 /* An erase unit should start with this value */ #define RFD_MAGIC 0x9193 /* the second value is 0xffff or 0xffc8; function unknown */ /* the third value is always 0xffff, ignored */ /* next is an array of mapping for each corresponding sector */ #define HEADER_MAP_OFFSET 3 #define SECTOR_DELETED 0x0000 #define SECTOR_ZERO 0xfffe #define SECTOR_FREE 0xffff #define SECTOR_SIZE 512 #define SECTORS_PER_TRACK 63 struct block { enum { BLOCK_OK, BLOCK_ERASING, BLOCK_ERASED, BLOCK_UNUSED, BLOCK_FAILED } state; int free_sectors; int used_sectors; int erases; u_long offset; }; struct partition { struct mtd_blktrans_dev mbd; u_int block_size; /* size of erase unit */ u_int total_blocks; /* number of erase units */ u_int header_sectors_per_block; /* header sectors in erase unit */ u_int data_sectors_per_block; /* data sectors in erase unit */ u_int sector_count; /* sectors in translated disk */ u_int header_size; /* bytes in header sector */ int reserved_block; /* block next up for reclaim */ int current_block; /* block to write to */ u16 *header_cache; /* cached header */ int is_reclaiming; int cylinders; int errors; u_long *sector_map; struct block *blocks; }; static int rfd_ftl_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf); static int build_block_map(struct partition *part, int block_no) { struct block *block = &part->blocks[block_no]; int i; block->offset = part->block_size * block_no; if (le16_to_cpu(part->header_cache[0]) != RFD_MAGIC) { block->state = BLOCK_UNUSED; return -ENOENT; } block->state = BLOCK_OK; for (i=0; i<part->data_sectors_per_block; i++) { u16 entry; entry = le16_to_cpu(part->header_cache[HEADER_MAP_OFFSET + i]); if (entry == SECTOR_DELETED) continue; if (entry == SECTOR_FREE) { block->free_sectors++; continue; } if (entry == SECTOR_ZERO) entry = 0; if (entry >= part->sector_count) { printk(KERN_WARNING PREFIX "'%s': unit #%d: entry %d corrupt, " "sector %d out of range\n", part->mbd.mtd->name, block_no, i, entry); continue; } if (part->sector_map[entry] != -1) { printk(KERN_WARNING PREFIX "'%s': more than one entry for sector %d\n", part->mbd.mtd->name, entry); part->errors = 1; continue; } part->sector_map[entry] = block->offset + (i + part->header_sectors_per_block) * SECTOR_SIZE; block->used_sectors++; } if (block->free_sectors == part->data_sectors_per_block) part->reserved_block = block_no; return 0; } static int scan_header(struct partition *part) { int sectors_per_block; int i, rc = -ENOMEM; int blocks_found; size_t retlen; sectors_per_block = part->block_size / SECTOR_SIZE; part->total_blocks = (u32)part->mbd.mtd->size / part->block_size; if (part->total_blocks < 2) return -ENOENT; /* each erase block has three bytes header, followed by the map */ part->header_sectors_per_block = ((HEADER_MAP_OFFSET + sectors_per_block) * sizeof(u16) + SECTOR_SIZE - 1) / SECTOR_SIZE; part->data_sectors_per_block = sectors_per_block - part->header_sectors_per_block; part->header_size = (HEADER_MAP_OFFSET + part->data_sectors_per_block) * sizeof(u16); part->cylinders = (part->data_sectors_per_block * (part->total_blocks - 1) - 1) / SECTORS_PER_TRACK; part->sector_count = part->cylinders * SECTORS_PER_TRACK; part->current_block = -1; part->reserved_block = -1; part->is_reclaiming = 0; part->header_cache = kmalloc(part->header_size, GFP_KERNEL); if (!part->header_cache) goto err; part->blocks = kcalloc(part->total_blocks, sizeof(struct block), GFP_KERNEL); if (!part->blocks) goto err; part->sector_map = vmalloc(array_size(sizeof(u_long), part->sector_count)); if (!part->sector_map) goto err; for (i=0; i<part->sector_count; i++) part->sector_map[i] = -1; for (i=0, blocks_found=0; i<part->total_blocks; i++) { rc = mtd_read(part->mbd.mtd, i * part->block_size, part->header_size, &retlen, (u_char *)part->header_cache); if (!rc && retlen != part->header_size) rc = -EIO; if (rc) goto err; if (!build_block_map(part, i)) blocks_found++; } if (blocks_found == 0) { printk(KERN_NOTICE PREFIX "no RFD magic found in '%s'\n", part->mbd.mtd->name); rc = -ENOENT; goto err; } if (part->reserved_block == -1) { printk(KERN_WARNING PREFIX "'%s': no empty erase unit found\n", part->mbd.mtd->name); part->errors = 1; } return 0; err: vfree(part->sector_map); kfree(part->header_cache); kfree(part->blocks); return rc; } static int rfd_ftl_readsect(struct mtd_blktrans_dev *dev, u_long sector, char *buf) { struct partition *part = (struct partition*)dev; u_long addr; size_t retlen; int rc; if (sector >= part->sector_count) return -EIO; addr = part->sector_map[sector]; if (addr != -1) { rc = mtd_read(part->mbd.mtd, addr, SECTOR_SIZE, &retlen, (u_char *)buf); if (!rc && retlen != SECTOR_SIZE) rc = -EIO; if (rc) { printk(KERN_WARNING PREFIX "error reading '%s' at " "0x%lx\n", part->mbd.mtd->name, addr); return rc; } } else memset(buf, 0, SECTOR_SIZE); return 0; } static int erase_block(struct partition *part, int block) { struct erase_info *erase; int rc; erase = kmalloc(sizeof(struct erase_info), GFP_KERNEL); if (!erase) return -ENOMEM; erase->addr = part->blocks[block].offset; erase->len = part->block_size; part->blocks[block].state = BLOCK_ERASING; part->blocks[block].free_sectors = 0; rc = mtd_erase(part->mbd.mtd, erase); if (rc) { printk(KERN_ERR PREFIX "erase of region %llx,%llx on '%s' " "failed\n", (unsigned long long)erase->addr, (unsigned long long)erase->len, part->mbd.mtd->name); part->blocks[block].state = BLOCK_FAILED; part->blocks[block].free_sectors = 0; part->blocks[block].used_sectors = 0; } else { u16 magic = cpu_to_le16(RFD_MAGIC); size_t retlen; part->blocks[block].state = BLOCK_ERASED; part->blocks[block].free_sectors = part->data_sectors_per_block; part->blocks[block].used_sectors = 0; part->blocks[block].erases++; rc = mtd_write(part->mbd.mtd, part->blocks[block].offset, sizeof(magic), &retlen, (u_char *)&magic); if (!rc && retlen != sizeof(magic)) rc = -EIO; if (rc) { pr_err(PREFIX "'%s': unable to write RFD header at 0x%lx\n", part->mbd.mtd->name, part->blocks[block].offset); part->blocks[block].state = BLOCK_FAILED; } else { part->blocks[block].state = BLOCK_OK; } } kfree(erase); return rc; } static int move_block_contents(struct partition *part, int block_no, u_long *old_sector) { void *sector_data; u16 *map; size_t retlen; int i, rc = -ENOMEM; part->is_reclaiming = 1; sector_data = kmalloc(SECTOR_SIZE, GFP_KERNEL); if (!sector_data) goto err3; map = kmalloc(part->header_size, GFP_KERNEL); if (!map) goto err2; rc = mtd_read(part->mbd.mtd, part->blocks[block_no].offset, part->header_size, &retlen, (u_char *)map); if (!rc && retlen != part->header_size) rc = -EIO; if (rc) { printk(KERN_ERR PREFIX "error reading '%s' at " "0x%lx\n", part->mbd.mtd->name, part->blocks[block_no].offset); goto err; } for (i=0; i<part->data_sectors_per_block; i++) { u16 entry = le16_to_cpu(map[HEADER_MAP_OFFSET + i]); u_long addr; if (entry == SECTOR_FREE || entry == SECTOR_DELETED) continue; if (entry == SECTOR_ZERO) entry = 0; /* already warned about and ignored in build_block_map() */ if (entry >= part->sector_count) continue; addr = part->blocks[block_no].offset + (i + part->header_sectors_per_block) * SECTOR_SIZE; if (*old_sector == addr) { *old_sector = -1; if (!part->blocks[block_no].used_sectors--) { rc = erase_block(part, block_no); break; } continue; } rc = mtd_read(part->mbd.mtd, addr, SECTOR_SIZE, &retlen, sector_data); if (!rc && retlen != SECTOR_SIZE) rc = -EIO; if (rc) { printk(KERN_ERR PREFIX "'%s': Unable to " "read sector for relocation\n", part->mbd.mtd->name); goto err; } rc = rfd_ftl_writesect((struct mtd_blktrans_dev*)part, entry, sector_data); if (rc) goto err; } err: kfree(map); err2: kfree(sector_data); err3: part->is_reclaiming = 0; return rc; } static int reclaim_block(struct partition *part, u_long *old_sector) { int block, best_block, score, old_sector_block; int rc; /* we have a race if sync doesn't exist */ mtd_sync(part->mbd.mtd); score = 0x7fffffff; /* MAX_INT */ best_block = -1; if (*old_sector != -1) old_sector_block = *old_sector / part->block_size; else old_sector_block = -1; for (block=0; block<part->total_blocks; block++) { int this_score; if (block == part->reserved_block) continue; /* * Postpone reclaiming if there is a free sector as * more removed sectors is more efficient (have to move * less). */ if (part->blocks[block].free_sectors) return 0; this_score = part->blocks[block].used_sectors; if (block == old_sector_block) this_score--; else { /* no point in moving a full block */ if (part->blocks[block].used_sectors == part->data_sectors_per_block) continue; } this_score += part->blocks[block].erases; if (this_score < score) { best_block = block; score = this_score; } } if (best_block == -1) return -ENOSPC; part->current_block = -1; part->reserved_block = best_block; pr_debug("reclaim_block: reclaiming block #%d with %d used " "%d free sectors\n", best_block, part->blocks[best_block].used_sectors, part->blocks[best_block].free_sectors); if (part->blocks[best_block].used_sectors) rc = move_block_contents(part, best_block, old_sector); else rc = erase_block(part, best_block); return rc; } /* * IMPROVE: It would be best to choose the block with the most deleted sectors, * because if we fill that one up first it'll have the most chance of having * the least live sectors at reclaim. */ static int find_free_block(struct partition *part) { int block, stop; block = part->current_block == -1 ? jiffies % part->total_blocks : part->current_block; stop = block; do { if (part->blocks[block].free_sectors && block != part->reserved_block) return block; if (part->blocks[block].state == BLOCK_UNUSED) erase_block(part, block); if (++block >= part->total_blocks) block = 0; } while (block != stop); return -1; } static int find_writable_block(struct partition *part, u_long *old_sector) { int rc, block; size_t retlen; block = find_free_block(part); if (block == -1) { if (!part->is_reclaiming) { rc = reclaim_block(part, old_sector); if (rc) goto err; block = find_free_block(part); } if (block == -1) { rc = -ENOSPC; goto err; } } rc = mtd_read(part->mbd.mtd, part->blocks[block].offset, part->header_size, &retlen, (u_char *)part->header_cache); if (!rc && retlen != part->header_size) rc = -EIO; if (rc) { printk(KERN_ERR PREFIX "'%s': unable to read header at " "0x%lx\n", part->mbd.mtd->name, part->blocks[block].offset); goto err; } part->current_block = block; err: return rc; } static int mark_sector_deleted(struct partition *part, u_long old_addr) { int block, offset, rc; u_long addr; size_t retlen; u16 del = cpu_to_le16(SECTOR_DELETED); block = old_addr / part->block_size; offset = (old_addr % part->block_size) / SECTOR_SIZE - part->header_sectors_per_block; addr = part->blocks[block].offset + (HEADER_MAP_OFFSET + offset) * sizeof(u16); rc = mtd_write(part->mbd.mtd, addr, sizeof(del), &retlen, (u_char *)&del); if (!rc && retlen != sizeof(del)) rc = -EIO; if (rc) { printk(KERN_ERR PREFIX "error writing '%s' at " "0x%lx\n", part->mbd.mtd->name, addr); goto err; } if (block == part->current_block) part->header_cache[offset + HEADER_MAP_OFFSET] = del; part->blocks[block].used_sectors--; if (!part->blocks[block].used_sectors && !part->blocks[block].free_sectors) rc = erase_block(part, block); err: return rc; } static int find_free_sector(const struct partition *part, const struct block *block) { int i, stop; i = stop = part->data_sectors_per_block - block->free_sectors; do { if (le16_to_cpu(part->header_cache[HEADER_MAP_OFFSET + i]) == SECTOR_FREE) return i; if (++i == part->data_sectors_per_block) i = 0; } while(i != stop); return -1; } static int do_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf, ulong *old_addr) { struct partition *part = (struct partition*)dev; struct block *block; u_long addr; int i; int rc; size_t retlen; u16 entry; if (part->current_block == -1 || !part->blocks[part->current_block].free_sectors) { rc = find_writable_block(part, old_addr); if (rc) goto err; } block = &part->blocks[part->current_block]; i = find_free_sector(part, block); if (i < 0) { rc = -ENOSPC; goto err; } addr = (i + part->header_sectors_per_block) * SECTOR_SIZE + block->offset; rc = mtd_write(part->mbd.mtd, addr, SECTOR_SIZE, &retlen, (u_char *)buf); if (!rc && retlen != SECTOR_SIZE) rc = -EIO; if (rc) { printk(KERN_ERR PREFIX "error writing '%s' at 0x%lx\n", part->mbd.mtd->name, addr); goto err; } part->sector_map[sector] = addr; entry = cpu_to_le16(sector == 0 ? SECTOR_ZERO : sector); part->header_cache[i + HEADER_MAP_OFFSET] = entry; addr = block->offset + (HEADER_MAP_OFFSET + i) * sizeof(u16); rc = mtd_write(part->mbd.mtd, addr, sizeof(entry), &retlen, (u_char *)&entry); if (!rc && retlen != sizeof(entry)) rc = -EIO; if (rc) { printk(KERN_ERR PREFIX "error writing '%s' at 0x%lx\n", part->mbd.mtd->name, addr); goto err; } block->used_sectors++; block->free_sectors--; err: return rc; } static int rfd_ftl_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf) { struct partition *part = (struct partition*)dev; u_long old_addr; int i; int rc = 0; pr_debug("rfd_ftl_writesect(sector=0x%lx)\n", sector); if (part->reserved_block == -1) { rc = -EACCES; goto err; } if (sector >= part->sector_count) { rc = -EIO; goto err; } old_addr = part->sector_map[sector]; for (i=0; i<SECTOR_SIZE; i++) { if (!buf[i]) continue; rc = do_writesect(dev, sector, buf, &old_addr); if (rc) goto err; break; } if (i == SECTOR_SIZE) part->sector_map[sector] = -1; if (old_addr != -1) rc = mark_sector_deleted(part, old_addr); err: return rc; } static int rfd_ftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo) { struct partition *part = (struct partition*)dev; geo->heads = 1; geo->sectors = SECTORS_PER_TRACK; geo->cylinders = part->cylinders; return 0; } static void rfd_ftl_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd) { struct partition *part; if (mtd->type != MTD_NORFLASH || mtd->size > UINT_MAX) return; part = kzalloc(sizeof(struct partition), GFP_KERNEL); if (!part) return; part->mbd.mtd = mtd; if (block_size) part->block_size = block_size; else { if (!mtd->erasesize) { printk(KERN_WARNING PREFIX "please provide block_size"); goto out; } else part->block_size = mtd->erasesize; } if (scan_header(part) == 0) { part->mbd.size = part->sector_count; part->mbd.tr = tr; part->mbd.devnum = -1; if (!(mtd->flags & MTD_WRITEABLE)) part->mbd.readonly = 1; else if (part->errors) { printk(KERN_WARNING PREFIX "'%s': errors found, " "setting read-only\n", mtd->name); part->mbd.readonly = 1; } printk(KERN_INFO PREFIX "name: '%s' type: %d flags %x\n", mtd->name, mtd->type, mtd->flags); if (!add_mtd_blktrans_dev((void*)part)) return; } out: kfree(part); } static void rfd_ftl_remove_dev(struct mtd_blktrans_dev *dev) { struct partition *part = (struct partition*)dev; int i; for (i=0; i<part->total_blocks; i++) { pr_debug("rfd_ftl_remove_dev:'%s': erase unit #%02d: %d erases\n", part->mbd.mtd->name, i, part->blocks[i].erases); } del_mtd_blktrans_dev(dev); vfree(part->sector_map); kfree(part->header_cache); kfree(part->blocks); } static struct mtd_blktrans_ops rfd_ftl_tr = { .name = "rfd", .major = RFD_FTL_MAJOR, .part_bits = PART_BITS, .blksize = SECTOR_SIZE, .readsect = rfd_ftl_readsect, .writesect = rfd_ftl_writesect, .getgeo = rfd_ftl_getgeo, .add_mtd = rfd_ftl_add_mtd, .remove_dev = rfd_ftl_remove_dev, .owner = THIS_MODULE, }; module_mtd_blktrans(rfd_ftl_tr); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Sean Young <sean@mess.org>"); MODULE_DESCRIPTION("Support code for RFD Flash Translation Layer, " "used by General Software's Embedded BIOS");