build.c

基于linux-2.6.28的mtd驱动

	err = cdev_add(&ubi->cdev, dev, 1);
	if (err) {
		ubi_err("cannot add character device");
		goto out_unreg;
	}

	err = ubi_sysfs_init(ubi);
	if (err)
		goto out_sysfs;

	for (i = 0; i < ubi->vtbl_slots; i++)
		if (ubi->volumes[i]) {
			err = ubi_add_volume(ubi, ubi->volumes[i]);
			if (err) {
				ubi_err("cannot add volume %d", i);
				goto out_volumes;
			}
		}

	return 0;

out_volumes:
	kill_volumes(ubi);
	do_free = 0;
out_sysfs:
	ubi_sysfs_close(ubi);
	cdev_del(&ubi->cdev);
out_unreg:
	if (do_free)
		free_user_volumes(ubi);
	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
	ubi_err("cannot initialize UBI %s, error %d", ubi->ubi_name, err);
	return err;
}

/**
 * uif_close - close user interfaces for an UBI device.
 * @ubi: UBI device description object
 *
 * Note, since this function un-registers UBI volume device objects (@vol->dev),
 * the memory allocated voe the volumes is freed as well (in the release
 * function).
 */
static void uif_close(struct ubi_device *ubi)
{
	kill_volumes(ubi);
	ubi_sysfs_close(ubi);
	cdev_del(&ubi->cdev);
	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
}

/**
 * free_internal_volumes - free internal volumes.
 * @ubi: UBI device description object
 */
static void free_internal_volumes(struct ubi_device *ubi)
{
	int i;

	for (i = ubi->vtbl_slots;
	     i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
		kfree(ubi->volumes[i]->eba_tbl);
		kfree(ubi->volumes[i]);
	}
}

/**
 * attach_by_scanning - attach an MTD device using scanning method.
 * @ubi: UBI device descriptor
 *
 * This function returns zero in case of success and a negative error code in
 * case of failure.
 *
 * Note, currently this is the only method to attach UBI devices. Hopefully in
 * the future we'll have more scalable attaching methods and avoid full media
 * scanning. But even in this case scanning will be needed as a fall-back
 * attaching method if there are some on-flash table corruptions.
 */
static int attach_by_scanning(struct ubi_device *ubi)
{
	int err;
	struct ubi_scan_info *si;

	si = ubi_scan(ubi);
	if (IS_ERR(si))
		return PTR_ERR(si);

	ubi->bad_peb_count = si->bad_peb_count;
	ubi->good_peb_count = ubi->peb_count - ubi->bad_peb_count;
	ubi->max_ec = si->max_ec;
	ubi->mean_ec = si->mean_ec;

	err = ubi_read_volume_table(ubi, si);
	if (err)
		goto out_si;

	err = ubi_wl_init_scan(ubi, si);
	if (err)
		goto out_vtbl;

	err = ubi_eba_init_scan(ubi, si);
	if (err)
		goto out_wl;

	ubi_scan_destroy_si(si);
	return 0;

out_wl:
	ubi_wl_close(ubi);
out_vtbl:
	free_internal_volumes(ubi);
	vfree(ubi->vtbl);
out_si:
	ubi_scan_destroy_si(si);
	return err;
}

/**
 * io_init - initialize I/O sub-system for a given UBI device.
 * @ubi: UBI device description object
 *
 * If @ubi->vid_hdr_offset or @ubi->leb_start is zero, default offsets are
 * assumed:
 *   o EC header is always at offset zero - this cannot be changed;
 *   o VID header starts just after the EC header at the closest address
 *     aligned to @io->hdrs_min_io_size;
 *   o data starts just after the VID header at the closest address aligned to
 *     @io->min_io_size
 *
 * This function returns zero in case of success and a negative error code in
 * case of failure.
 */
static int io_init(struct ubi_device *ubi)
{
	if (ubi->mtd->numeraseregions != 0) {
		/*
		 * Some flashes have several erase regions. Different regions
		 * may have different eraseblock size and other
		 * characteristics. It looks like mostly multi-region flashes
		 * have one "main" region and one or more small regions to
		 * store boot loader code or boot parameters or whatever. I
		 * guess we should just pick the largest region. But this is
		 * not implemented.
		 */
		ubi_err("multiple regions, not implemented");
		return -EINVAL;
	}

	if (ubi->vid_hdr_offset < 0)
		return -EINVAL;

	/*
	 * Note, in this implementation we support MTD devices with 0x7FFFFFFF
	 * physical eraseblocks maximum.
	 */

	ubi->peb_size   = ubi->mtd->erasesize;
	ubi->peb_count  = ubi->mtd->size / ubi->mtd->erasesize;
	ubi->flash_size = ubi->mtd->size;

	if (ubi->mtd->block_isbad && ubi->mtd->block_markbad)
		ubi->bad_allowed = 1;

	ubi->min_io_size = ubi->mtd->writesize;
	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;

	/*
	 * Make sure minimal I/O unit is power of 2. Note, there is no
	 * fundamental reason for this assumption. It is just an optimization
	 * which allows us to avoid costly division operations.
	 */
	if (!is_power_of_2(ubi->min_io_size)) {
		ubi_err("min. I/O unit (%d) is not power of 2",
			ubi->min_io_size);
		return -EINVAL;
	}

	ubi_assert(ubi->hdrs_min_io_size > 0);
	ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size);
	ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0);

	/* Calculate default aligned sizes of EC and VID headers */
	ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size);
	ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size);

	dbg_msg("min_io_size      %d", ubi->min_io_size);
	dbg_msg("hdrs_min_io_size %d", ubi->hdrs_min_io_size);
	dbg_msg("ec_hdr_alsize    %d", ubi->ec_hdr_alsize);
	dbg_msg("vid_hdr_alsize   %d", ubi->vid_hdr_alsize);

	if (ubi->vid_hdr_offset == 0)
		/* Default offset */
		ubi->vid_hdr_offset = ubi->vid_hdr_aloffset =
				      ubi->ec_hdr_alsize;
	else {
		ubi->vid_hdr_aloffset = ubi->vid_hdr_offset &
						~(ubi->hdrs_min_io_size - 1);
		ubi->vid_hdr_shift = ubi->vid_hdr_offset -
						ubi->vid_hdr_aloffset;
	}

	/* Similar for the data offset */
	ubi->leb_start = ubi->vid_hdr_offset + UBI_EC_HDR_SIZE;
	ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);

	dbg_msg("vid_hdr_offset   %d", ubi->vid_hdr_offset);
	dbg_msg("vid_hdr_aloffset %d", ubi->vid_hdr_aloffset);
	dbg_msg("vid_hdr_shift    %d", ubi->vid_hdr_shift);
	dbg_msg("leb_start        %d", ubi->leb_start);

	/* The shift must be aligned to 32-bit boundary */
	if (ubi->vid_hdr_shift % 4) {
		ubi_err("unaligned VID header shift %d",
			ubi->vid_hdr_shift);
		return -EINVAL;
	}

	/* Check sanity */
	if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE ||
	    ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE ||
	    ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE ||
	    ubi->leb_start & (ubi->min_io_size - 1)) {
		ubi_err("bad VID header (%d) or data offsets (%d)",
			ubi->vid_hdr_offset, ubi->leb_start);
		return -EINVAL;
	}

	/*
	 * It may happen that EC and VID headers are situated in one minimal
	 * I/O unit. In this case we can only accept this UBI image in
	 * read-only mode.
	 */
	if (ubi->vid_hdr_offset + UBI_VID_HDR_SIZE <= ubi->hdrs_min_io_size) {
		ubi_warn("EC and VID headers are in the same minimal I/O unit, "
			 "switch to read-only mode");
		ubi->ro_mode = 1;
	}

	ubi->leb_size = ubi->peb_size - ubi->leb_start;

	if (!(ubi->mtd->flags & MTD_WRITEABLE)) {
		ubi_msg("MTD device %d is write-protected, attach in "
			"read-only mode", ubi->mtd->index);
		ubi->ro_mode = 1;
	}

	ubi_msg("physical eraseblock size:   %d bytes (%d KiB)",
		ubi->peb_size, ubi->peb_size >> 10);
	ubi_msg("logical eraseblock size:    %d bytes", ubi->leb_size);
	ubi_msg("smallest flash I/O unit:    %d", ubi->min_io_size);
	if (ubi->hdrs_min_io_size != ubi->min_io_size)
		ubi_msg("sub-page size:              %d",
			ubi->hdrs_min_io_size);
	ubi_msg("VID header offset:          %d (aligned %d)",
		ubi->vid_hdr_offset, ubi->vid_hdr_aloffset);
	ubi_msg("data offset:                %d", ubi->leb_start);

	/*
	 * Note, ideally, we have to initialize ubi->bad_peb_count here. But
	 * unfortunately, MTD does not provide this information. We should loop
	 * over all physical eraseblocks and invoke mtd->block_is_bad() for
	 * each physical eraseblock. So, we skip ubi->bad_peb_count
	 * uninitialized and initialize it after scanning.
	 */

	return 0;
}

/**
 * autoresize - re-size the volume which has the "auto-resize" flag set.
 * @ubi: UBI device description object
 * @vol_id: ID of the volume to re-size
 *
 * This function re-sizes the volume marked by the @UBI_VTBL_AUTORESIZE_FLG in
 * the volume table to the largest possible size. See comments in ubi-header.h
 * for more description of the flag. Returns zero in case of success and a
 * negative error code in case of failure.
 */
static int autoresize(struct ubi_device *ubi, int vol_id)
{
	struct ubi_volume_desc desc;
	struct ubi_volume *vol = ubi->volumes[vol_id];
	int err, old_reserved_pebs = vol->reserved_pebs;

	/*
	 * Clear the auto-resize flag in the volume in-memory copy of the
	 * volume table, and 'ubi_resize_volume()' will propagate this change
	 * to the flash.
	 */
	ubi->vtbl[vol_id].flags &= ~UBI_VTBL_AUTORESIZE_FLG;

	if (ubi->avail_pebs == 0) {
		struct ubi_vtbl_record vtbl_rec;

		/*
		 * No available PEBs to re-size the volume, clear the flag on
		 * flash and exit.
		 */
		memcpy(&vtbl_rec, &ubi->vtbl[vol_id],
		       sizeof(struct ubi_vtbl_record));
		err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
		if (err)
			ubi_err("cannot clean auto-resize flag for volume %d",
				vol_id);
	} else {
		desc.vol = vol;
		err = ubi_resize_volume(&desc,
					old_reserved_pebs + ubi->avail_pebs);
		if (err)
			ubi_err("cannot auto-resize volume %d", vol_id);
	}

	if (err)
		return err;

	ubi_msg("volume %d (\"%s\") re-sized from %d to %d LEBs", vol_id,
		vol->name, old_reserved_pebs, vol->reserved_pebs);
	return 0;
}

/**
 * ubi_attach_mtd_dev - attach an MTD device.
 * @mtd: MTD device description object
 * @ubi_num: number to assign to the new UBI device
 * @vid_hdr_offset: VID header offset
 *
 * This function attaches MTD device @mtd_dev to UBI and assign @ubi_num number
 * to the newly created UBI device, unless @ubi_num is %UBI_DEV_NUM_AUTO, in
 * which case this function finds a vacant device number and assigns it
 * automatically. Returns the new UBI device number in case of success and a
 * negative error code in case of failure.
 *
 * Note, the invocations of this function has to be serialized by the
 * @ubi_devices_mutex.
 */
int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset)
{
	struct ubi_device *ubi;
	int i, err, do_free = 1;

	/*
	 * Check if we already have the same MTD device attached.
	 *
	 * Note, this function assumes that UBI devices creations and deletions
	 * are serialized, so it does not take the &ubi_devices_lock.
	 */
	for (i = 0; i < UBI_MAX_DEVICES; i++) {
		ubi = ubi_devices[i];
		if (ubi && mtd->index == ubi->mtd->index) {
			dbg_err("mtd%d is already attached to ubi%d",
				mtd->index, i);
			return -EEXIST;
		}
	}

	/*
	 * Make sure this MTD device is not emulated on top of an UBI volume
	 * already. Well, generally this recursion works fine, but there are
	 * different problems like the UBI module takes a reference to itself
	 * by attaching (and thus, opening) the emulated MTD device. This
	 * results in inability to unload the module. And in general it makes
	 * no sense to attach emulated MTD devices, so we prohibit this.
	 */
	if (mtd->type == MTD_UBIVOLUME) {
		ubi_err("refuse attaching mtd%d - it is already emulated on "
			"top of UBI", mtd->index);
		return -EINVAL;
	}

	if (ubi_num == UBI_DEV_NUM_AUTO) {
		/* Search for an empty slot in the @ubi_devices array */
		for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)
			if (!ubi_devices[ubi_num])
				break;
		if (ubi_num == UBI_MAX_DEVICES) {
			dbg_err("only %d UBI devices may be created",
				UBI_MAX_DEVICES);
			return -ENFILE;
		}
	} else {
		if (ubi_num >= UBI_MAX_DEVICES)
			return -EINVAL;

		/* Make sure ubi_num is not busy */
		if (ubi_devices[ubi_num]) {
			dbg_err("ubi%d already exists", ubi_num);
			return -EEXIST;
		}
	}

	ubi = kzalloc(sizeof(struct ubi_device), GFP_KERNEL);
	if (!ubi)
		return -ENOMEM;

	ubi->mtd = mtd;
	ubi->ubi_num = ubi_num;
	ubi->vid_hdr_offset = vid_hdr_offset;
	ubi->autoresize_vol_id = -1;

	mutex_init(&ubi->buf_mutex);
	mutex_init(&ubi->ckvol_mutex);
	mutex_init(&ubi->mult_mutex);
	mutex_init(&ubi->volumes_mutex);
	spin_lock_init(&ubi->volumes_lock);