ftl.c

基于linux-2.6.28的mtd驱动

	/* Invalidate cache */
	part->bam_index = 0xffff;

	ret = part->mbd.mtd->read(part->mbd.mtd,
		       part->EUNInfo[eun].Offset + le32_to_cpu(part->header.BAMOffset),
		       part->BlocksPerUnit * sizeof(u_int32_t),
		       &retlen, (u_char *) (part->bam_cache));

	if (ret) {
	    printk(KERN_WARNING"ftl: Error reading BAM in find_free\n");
	    return 0;
	}
	part->bam_index = eun;
    }

    /* Find a free block */
    for (blk = 0; blk < part->BlocksPerUnit; blk++)
	if (BLOCK_FREE(le32_to_cpu(part->bam_cache[blk]))) break;
    if (blk == part->BlocksPerUnit) {
#ifdef PSYCHO_DEBUG
	static int ne = 0;
	if (++ne == 1)
	    dump_lists(part);
#endif
	printk(KERN_NOTICE "ftl_cs: bad free list!\n");
	return 0;
    }
    DEBUG(2, "ftl_cs: found free block at %d in %d\n", blk, eun);
    return blk;

} /* find_free */


/*======================================================================

    Read a series of sectors from an FTL partition.

======================================================================*/

static int ftl_read(partition_t *part, caddr_t buffer,
		    u_long sector, u_long nblocks)
{
    u_int32_t log_addr, bsize;
    u_long i;
    int ret;
    size_t offset, retlen;

    DEBUG(2, "ftl_cs: ftl_read(0x%p, 0x%lx, %ld)\n",
	  part, sector, nblocks);
    if (!(part->state & FTL_FORMATTED)) {
	printk(KERN_NOTICE "ftl_cs: bad partition\n");
	return -EIO;
    }
    bsize = 1 << part->header.EraseUnitSize;

    for (i = 0; i < nblocks; i++) {
	if (((sector+i) * SECTOR_SIZE) >= le32_to_cpu(part->header.FormattedSize)) {
	    printk(KERN_NOTICE "ftl_cs: bad read offset\n");
	    return -EIO;
	}
	log_addr = part->VirtualBlockMap[sector+i];
	if (log_addr == 0xffffffff)
	    memset(buffer, 0, SECTOR_SIZE);
	else {
	    offset = (part->EUNInfo[log_addr / bsize].Offset
			  + (log_addr % bsize));
	    ret = part->mbd.mtd->read(part->mbd.mtd, offset, SECTOR_SIZE,
			   &retlen, (u_char *) buffer);

	    if (ret) {
		printk(KERN_WARNING "Error reading MTD device in ftl_read()\n");
		return ret;
	    }
	}
	buffer += SECTOR_SIZE;
    }
    return 0;
} /* ftl_read */

/*======================================================================

    Write a series of sectors to an FTL partition

======================================================================*/

static int set_bam_entry(partition_t *part, u_int32_t log_addr,
			 u_int32_t virt_addr)
{
    u_int32_t bsize, blk, le_virt_addr;
#ifdef PSYCHO_DEBUG
    u_int32_t old_addr;
#endif
    u_int16_t eun;
    int ret;
    size_t retlen, offset;

    DEBUG(2, "ftl_cs: set_bam_entry(0x%p, 0x%x, 0x%x)\n",
	  part, log_addr, virt_addr);
    bsize = 1 << part->header.EraseUnitSize;
    eun = log_addr / bsize;
    blk = (log_addr % bsize) / SECTOR_SIZE;
    offset = (part->EUNInfo[eun].Offset + blk * sizeof(u_int32_t) +
		  le32_to_cpu(part->header.BAMOffset));

#ifdef PSYCHO_DEBUG
    ret = part->mbd.mtd->read(part->mbd.mtd, offset, sizeof(u_int32_t),
                        &retlen, (u_char *)&old_addr);
    if (ret) {
	printk(KERN_WARNING"ftl: Error reading old_addr in set_bam_entry: %d\n",ret);
	return ret;
    }
    old_addr = le32_to_cpu(old_addr);

    if (((virt_addr == 0xfffffffe) && !BLOCK_FREE(old_addr)) ||
	((virt_addr == 0) && (BLOCK_TYPE(old_addr) != BLOCK_DATA)) ||
	(!BLOCK_DELETED(virt_addr) && (old_addr != 0xfffffffe))) {
	static int ne = 0;
	if (++ne < 5) {
	    printk(KERN_NOTICE "ftl_cs: set_bam_entry() inconsistency!\n");
	    printk(KERN_NOTICE "ftl_cs:   log_addr = 0x%x, old = 0x%x"
		   ", new = 0x%x\n", log_addr, old_addr, virt_addr);
	}
	return -EIO;
    }
#endif
    le_virt_addr = cpu_to_le32(virt_addr);
    if (part->bam_index == eun) {
#ifdef PSYCHO_DEBUG
	if (le32_to_cpu(part->bam_cache[blk]) != old_addr) {
	    static int ne = 0;
	    if (++ne < 5) {
		printk(KERN_NOTICE "ftl_cs: set_bam_entry() "
		       "inconsistency!\n");
		printk(KERN_NOTICE "ftl_cs:   log_addr = 0x%x, cache"
		       " = 0x%x\n",
		       le32_to_cpu(part->bam_cache[blk]), old_addr);
	    }
	    return -EIO;
	}
#endif
	part->bam_cache[blk] = le_virt_addr;
    }
    ret = part->mbd.mtd->write(part->mbd.mtd, offset, sizeof(u_int32_t),
                            &retlen, (u_char *)&le_virt_addr);

    if (ret) {
	printk(KERN_NOTICE "ftl_cs: set_bam_entry() failed!\n");
	printk(KERN_NOTICE "ftl_cs:   log_addr = 0x%x, new = 0x%x\n",
	       log_addr, virt_addr);
    }
    return ret;
} /* set_bam_entry */

static int ftl_write(partition_t *part, caddr_t buffer,
		     u_long sector, u_long nblocks)
{
    u_int32_t bsize, log_addr, virt_addr, old_addr, blk;
    u_long i;
    int ret;
    size_t retlen, offset;

    DEBUG(2, "ftl_cs: ftl_write(0x%p, %ld, %ld)\n",
	  part, sector, nblocks);
    if (!(part->state & FTL_FORMATTED)) {
	printk(KERN_NOTICE "ftl_cs: bad partition\n");
	return -EIO;
    }
    /* See if we need to reclaim space, before we start */
    while (part->FreeTotal < nblocks) {
	ret = reclaim_block(part);
	if (ret)
	    return ret;
    }

    bsize = 1 << part->header.EraseUnitSize;

    virt_addr = sector * SECTOR_SIZE | BLOCK_DATA;
    for (i = 0; i < nblocks; i++) {
	if (virt_addr >= le32_to_cpu(part->header.FormattedSize)) {
	    printk(KERN_NOTICE "ftl_cs: bad write offset\n");
	    return -EIO;
	}

	/* Grab a free block */
	blk = find_free(part);
	if (blk == 0) {
	    static int ne = 0;
	    if (++ne < 5)
		printk(KERN_NOTICE "ftl_cs: internal error: "
		       "no free blocks!\n");
	    return -ENOSPC;
	}

	/* Tag the BAM entry, and write the new block */
	log_addr = part->bam_index * bsize + blk * SECTOR_SIZE;
	part->EUNInfo[part->bam_index].Free--;
	part->FreeTotal--;
	if (set_bam_entry(part, log_addr, 0xfffffffe))
	    return -EIO;
	part->EUNInfo[part->bam_index].Deleted++;
	offset = (part->EUNInfo[part->bam_index].Offset +
		      blk * SECTOR_SIZE);
	ret = part->mbd.mtd->write(part->mbd.mtd, offset, SECTOR_SIZE, &retlen,
                                     buffer);

	if (ret) {
	    printk(KERN_NOTICE "ftl_cs: block write failed!\n");
	    printk(KERN_NOTICE "ftl_cs:   log_addr = 0x%x, virt_addr"
		   " = 0x%x, Offset = 0x%zx\n", log_addr, virt_addr,
		   offset);
	    return -EIO;
	}

	/* Only delete the old entry when the new entry is ready */
	old_addr = part->VirtualBlockMap[sector+i];
	if (old_addr != 0xffffffff) {
	    part->VirtualBlockMap[sector+i] = 0xffffffff;
	    part->EUNInfo[old_addr/bsize].Deleted++;
	    if (set_bam_entry(part, old_addr, 0))
		return -EIO;
	}

	/* Finally, set up the new pointers */
	if (set_bam_entry(part, log_addr, virt_addr))
	    return -EIO;
	part->VirtualBlockMap[sector+i] = log_addr;
	part->EUNInfo[part->bam_index].Deleted--;

	buffer += SECTOR_SIZE;
	virt_addr += SECTOR_SIZE;
    }
    return 0;
} /* ftl_write */

static int ftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
{
	partition_t *part = (void *)dev;
	u_long sect;

	/* Sort of arbitrary: round size down to 4KiB boundary */
	sect = le32_to_cpu(part->header.FormattedSize)/SECTOR_SIZE;

	geo->heads = 1;
	geo->sectors = 8;
	geo->cylinders = sect >> 3;

	return 0;
}

static int ftl_readsect(struct mtd_blktrans_dev *dev,
			      unsigned long block, char *buf)
{
	return ftl_read((void *)dev, buf, block, 1);
}

static int ftl_writesect(struct mtd_blktrans_dev *dev,
			      unsigned long block, char *buf)
{
	return ftl_write((void *)dev, buf, block, 1);
}

static int ftl_discardsect(struct mtd_blktrans_dev *dev,
			   unsigned long sector, unsigned nr_sects)
{
	partition_t *part = (void *)dev;
	uint32_t bsize = 1 << part->header.EraseUnitSize;

	DEBUG(1, "FTL erase sector %ld for %d sectors\n",
	      sector, nr_sects);

	while (nr_sects) {
		uint32_t old_addr = part->VirtualBlockMap[sector];
		if (old_addr != 0xffffffff) {
			part->VirtualBlockMap[sector] = 0xffffffff;
			part->EUNInfo[old_addr/bsize].Deleted++;
			if (set_bam_entry(part, old_addr, 0))
				return -EIO;
		}
		nr_sects--;
		sector++;
	}

	return 0;
}
/*====================================================================*/

static void ftl_freepart(partition_t *part)
{
	vfree(part->VirtualBlockMap);
	part->VirtualBlockMap = NULL;
	kfree(part->VirtualPageMap);
	part->VirtualPageMap = NULL;
	kfree(part->EUNInfo);
	part->EUNInfo = NULL;
	kfree(part->XferInfo);
	part->XferInfo = NULL;
	kfree(part->bam_cache);
	part->bam_cache = NULL;
} /* ftl_freepart */

static void ftl_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
{
	partition_t *partition;

	partition = kzalloc(sizeof(partition_t), GFP_KERNEL);

	if (!partition) {
		printk(KERN_WARNING "No memory to scan for FTL on %s\n",
		       mtd->name);
		return;
	}

	partition->mbd.mtd = mtd;

	if ((scan_header(partition) == 0) &&
	    (build_maps(partition) == 0)) {

		partition->state = FTL_FORMATTED;
#ifdef PCMCIA_DEBUG
		printk(KERN_INFO "ftl_cs: opening %d KiB FTL partition\n",
		       le32_to_cpu(partition->header.FormattedSize) >> 10);
#endif
		partition->mbd.size = le32_to_cpu(partition->header.FormattedSize) >> 9;

		partition->mbd.tr = tr;
		partition->mbd.devnum = -1;
		if (!add_mtd_blktrans_dev((void *)partition))
			return;
	}

	ftl_freepart(partition);
	kfree(partition);
}

static void ftl_remove_dev(struct mtd_blktrans_dev *dev)
{
	del_mtd_blktrans_dev(dev);
	ftl_freepart((partition_t *)dev);
	kfree(dev);
}

static struct mtd_blktrans_ops ftl_tr = {
	.name		= "ftl",
	.major		= FTL_MAJOR,
	.part_bits	= PART_BITS,
	.blksize 	= SECTOR_SIZE,
	.readsect	= ftl_readsect,
	.writesect	= ftl_writesect,
	.discard	= ftl_discardsect,
	.getgeo		= ftl_getgeo,
	.add_mtd	= ftl_add_mtd,
	.remove_dev	= ftl_remove_dev,
	.owner		= THIS_MODULE,
};

static int init_ftl(void)
{
	return register_mtd_blktrans(&ftl_tr);
}

static void __exit cleanup_ftl(void)
{
	deregister_mtd_blktrans(&ftl_tr);
}

module_init(init_ftl);
module_exit(cleanup_ftl);


MODULE_LICENSE("Dual MPL/GPL");
MODULE_AUTHOR("David Hinds <[e-mail]>");
MODULE_DESCRIPTION("Support code for Flash Translation Layer, used on PCMCIA devices");