diff options
Diffstat (limited to '')
-rw-r--r-- | drivers/mtd/rfd_ftl.c | 830 |
1 files changed, 830 insertions, 0 deletions
diff --git a/drivers/mtd/rfd_ftl.c b/drivers/mtd/rfd_ftl.c new file mode 100644 index 000000000..c546f8c5f --- /dev/null +++ b/drivers/mtd/rfd_ftl.c @@ -0,0 +1,830 @@ +// 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 = container_of(dev, struct partition, mbd); + 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 = container_of(dev, struct partition, mbd); + 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 = container_of(dev, struct partition, mbd); + 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_discardsect(struct mtd_blktrans_dev *dev, + unsigned long sector, unsigned int nr_sects) +{ + struct partition *part = container_of(dev, struct partition, mbd); + u_long addr; + int rc; + + while (nr_sects) { + if (sector >= part->sector_count) + return -EIO; + + addr = part->sector_map[sector]; + + if (addr != -1) { + rc = mark_sector_deleted(part, addr); + if (rc) + return rc; + + part->sector_map[sector] = -1; + } + + sector++; + nr_sects--; + } + + return 0; +} + +static int rfd_ftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo) +{ + struct partition *part = container_of(dev, struct partition, mbd); + + 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->type != MTD_RAM) || + 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(&part->mbd)) + return; + } +out: + kfree(part); +} + +static void rfd_ftl_remove_dev(struct mtd_blktrans_dev *dev) +{ + struct partition *part = container_of(dev, struct partition, mbd); + 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); + } + + vfree(part->sector_map); + kfree(part->header_cache); + kfree(part->blocks); + del_mtd_blktrans_dev(&part->mbd); +} + +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, + .discard = rfd_ftl_discardsect, + .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"); + |