diff --git a/drivers/mtd/ubi/scan.c b/drivers/mtd/ubi/scan.c
new file mode 100644
index 0000000..d5c1d27
--- /dev/null
+++ b/drivers/mtd/ubi/scan.c
@@ -0,0 +1,1360 @@
+/*
+ * Copyright (c) International Business Machines Corp., 2006
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Author: Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/*
+ * UBI scanning unit.
+ *
+ * This unit is responsible for scanning the flash media, checking UBI
+ * headers and providing complete information about the UBI flash image.
+ *
+ * The scanning information is represented by a &struct ubi_scan_info' object.
+ * Information about found volumes is represented by &struct ubi_scan_volume
+ * objects which are kept in volume RB-tree with root at the @volumes field.
+ * The RB-tree is indexed by the volume ID.
+ *
+ * Found logical eraseblocks are represented by &struct ubi_scan_leb objects.
+ * These objects are kept in per-volume RB-trees with the root at the
+ * corresponding &struct ubi_scan_volume object. To put it differently, we keep
+ * an RB-tree of per-volume objects and each of these objects is the root of
+ * RB-tree of per-eraseblock objects.
+ *
+ * Corrupted physical eraseblocks are put to the @corr list, free physical
+ * eraseblocks are put to the @free list and the physical eraseblock to be
+ * erased are put to the @erase list.
+ */
+
+#ifdef UBI_LINUX
+#include <linux/err.h>
+#include <linux/crc32.h>
+#include <asm/div64.h>
+#endif
+
+#include <ubi_uboot.h>
+#include "ubi.h"
+
+#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
+static int paranoid_check_si(struct ubi_device *ubi, struct ubi_scan_info *si);
+#else
+#define paranoid_check_si(ubi, si) 0
+#endif
+
+/* Temporary variables used during scanning */
+static struct ubi_ec_hdr *ech;
+static struct ubi_vid_hdr *vidh;
+
+/**
+ * add_to_list - add physical eraseblock to a list.
+ * @si: scanning information
+ * @pnum: physical eraseblock number to add
+ * @ec: erase counter of the physical eraseblock
+ * @list: the list to add to
+ *
+ * This function adds physical eraseblock @pnum to free, erase, corrupted or
+ * alien lists. Returns zero in case of success and a negative error code in
+ * case of failure.
+ */
+static int add_to_list(struct ubi_scan_info *si, int pnum, int ec,
+		       struct list_head *list)
+{
+	struct ubi_scan_leb *seb;
+
+	if (list == &si->free)
+		dbg_bld("add to free: PEB %d, EC %d", pnum, ec);
+	else if (list == &si->erase)
+		dbg_bld("add to erase: PEB %d, EC %d", pnum, ec);
+	else if (list == &si->corr)
+		dbg_bld("add to corrupted: PEB %d, EC %d", pnum, ec);
+	else if (list == &si->alien)
+		dbg_bld("add to alien: PEB %d, EC %d", pnum, ec);
+	else
+		BUG();
+
+	seb = kmalloc(sizeof(struct ubi_scan_leb), GFP_KERNEL);
+	if (!seb)
+		return -ENOMEM;
+
+	seb->pnum = pnum;
+	seb->ec = ec;
+	list_add_tail(&seb->u.list, list);
+	return 0;
+}
+
+/**
+ * validate_vid_hdr - check that volume identifier header is correct and
+ * consistent.
+ * @vid_hdr: the volume identifier header to check
+ * @sv: information about the volume this logical eraseblock belongs to
+ * @pnum: physical eraseblock number the VID header came from
+ *
+ * This function checks that data stored in @vid_hdr is consistent. Returns
+ * non-zero if an inconsistency was found and zero if not.
+ *
+ * Note, UBI does sanity check of everything it reads from the flash media.
+ * Most of the checks are done in the I/O unit. Here we check that the
+ * information in the VID header is consistent to the information in other VID
+ * headers of the same volume.
+ */
+static int validate_vid_hdr(const struct ubi_vid_hdr *vid_hdr,
+			    const struct ubi_scan_volume *sv, int pnum)
+{
+	int vol_type = vid_hdr->vol_type;
+	int vol_id = be32_to_cpu(vid_hdr->vol_id);
+	int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
+	int data_pad = be32_to_cpu(vid_hdr->data_pad);
+
+	if (sv->leb_count != 0) {
+		int sv_vol_type;
+
+		/*
+		 * This is not the first logical eraseblock belonging to this
+		 * volume. Ensure that the data in its VID header is consistent
+		 * to the data in previous logical eraseblock headers.
+		 */
+
+		if (vol_id != sv->vol_id) {
+			dbg_err("inconsistent vol_id");
+			goto bad;
+		}
+
+		if (sv->vol_type == UBI_STATIC_VOLUME)
+			sv_vol_type = UBI_VID_STATIC;
+		else
+			sv_vol_type = UBI_VID_DYNAMIC;
+
+		if (vol_type != sv_vol_type) {
+			dbg_err("inconsistent vol_type");
+			goto bad;
+		}
+
+		if (used_ebs != sv->used_ebs) {
+			dbg_err("inconsistent used_ebs");
+			goto bad;
+		}
+
+		if (data_pad != sv->data_pad) {
+			dbg_err("inconsistent data_pad");
+			goto bad;
+		}
+	}
+
+	return 0;
+
+bad:
+	ubi_err("inconsistent VID header at PEB %d", pnum);
+	ubi_dbg_dump_vid_hdr(vid_hdr);
+	ubi_dbg_dump_sv(sv);
+	return -EINVAL;
+}
+
+/**
+ * add_volume - add volume to the scanning information.
+ * @si: scanning information
+ * @vol_id: ID of the volume to add
+ * @pnum: physical eraseblock number
+ * @vid_hdr: volume identifier header
+ *
+ * If the volume corresponding to the @vid_hdr logical eraseblock is already
+ * present in the scanning information, this function does nothing. Otherwise
+ * it adds corresponding volume to the scanning information. Returns a pointer
+ * to the scanning volume object in case of success and a negative error code
+ * in case of failure.
+ */
+static struct ubi_scan_volume *add_volume(struct ubi_scan_info *si, int vol_id,
+					  int pnum,
+					  const struct ubi_vid_hdr *vid_hdr)
+{
+	struct ubi_scan_volume *sv;
+	struct rb_node **p = &si->volumes.rb_node, *parent = NULL;
+
+	ubi_assert(vol_id == be32_to_cpu(vid_hdr->vol_id));
+
+	/* Walk the volume RB-tree to look if this volume is already present */
+	while (*p) {
+		parent = *p;
+		sv = rb_entry(parent, struct ubi_scan_volume, rb);
+
+		if (vol_id == sv->vol_id)
+			return sv;
+
+		if (vol_id > sv->vol_id)
+			p = &(*p)->rb_left;
+		else
+			p = &(*p)->rb_right;
+	}
+
+	/* The volume is absent - add it */
+	sv = kmalloc(sizeof(struct ubi_scan_volume), GFP_KERNEL);
+	if (!sv)
+		return ERR_PTR(-ENOMEM);
+
+	sv->highest_lnum = sv->leb_count = 0;
+	sv->vol_id = vol_id;
+	sv->root = RB_ROOT;
+	sv->used_ebs = be32_to_cpu(vid_hdr->used_ebs);
+	sv->data_pad = be32_to_cpu(vid_hdr->data_pad);
+	sv->compat = vid_hdr->compat;
+	sv->vol_type = vid_hdr->vol_type == UBI_VID_DYNAMIC ? UBI_DYNAMIC_VOLUME
+							    : UBI_STATIC_VOLUME;
+	if (vol_id > si->highest_vol_id)
+		si->highest_vol_id = vol_id;
+
+	rb_link_node(&sv->rb, parent, p);
+	rb_insert_color(&sv->rb, &si->volumes);
+	si->vols_found += 1;
+	dbg_bld("added volume %d", vol_id);
+	return sv;
+}
+
+/**
+ * compare_lebs - find out which logical eraseblock is newer.
+ * @ubi: UBI device description object
+ * @seb: first logical eraseblock to compare
+ * @pnum: physical eraseblock number of the second logical eraseblock to
+ * compare
+ * @vid_hdr: volume identifier header of the second logical eraseblock
+ *
+ * This function compares 2 copies of a LEB and informs which one is newer. In
+ * case of success this function returns a positive value, in case of failure, a
+ * negative error code is returned. The success return codes use the following
+ * bits:
+ *     o bit 0 is cleared: the first PEB (described by @seb) is newer then the
+ *       second PEB (described by @pnum and @vid_hdr);
+ *     o bit 0 is set: the second PEB is newer;
+ *     o bit 1 is cleared: no bit-flips were detected in the newer LEB;
+ *     o bit 1 is set: bit-flips were detected in the newer LEB;
+ *     o bit 2 is cleared: the older LEB is not corrupted;
+ *     o bit 2 is set: the older LEB is corrupted.
+ */
+static int compare_lebs(struct ubi_device *ubi, const struct ubi_scan_leb *seb,
+			int pnum, const struct ubi_vid_hdr *vid_hdr)
+{
+	void *buf;
+	int len, err, second_is_newer, bitflips = 0, corrupted = 0;
+	uint32_t data_crc, crc;
+	struct ubi_vid_hdr *vh = NULL;
+	unsigned long long sqnum2 = be64_to_cpu(vid_hdr->sqnum);
+
+	if (seb->sqnum == 0 && sqnum2 == 0) {
+		long long abs, v1 = seb->leb_ver, v2 = be32_to_cpu(vid_hdr->leb_ver);
+
+		/*
+		 * UBI constantly increases the logical eraseblock version
+		 * number and it can overflow. Thus, we have to bear in mind
+		 * that versions that are close to %0xFFFFFFFF are less then
+		 * versions that are close to %0.
+		 *
+		 * The UBI WL unit guarantees that the number of pending tasks
+		 * is not greater then %0x7FFFFFFF. So, if the difference
+		 * between any two versions is greater or equivalent to
+		 * %0x7FFFFFFF, there was an overflow and the logical
+		 * eraseblock with lower version is actually newer then the one
+		 * with higher version.
+		 *
+		 * FIXME: but this is anyway obsolete and will be removed at
+		 * some point.
+		 */
+		dbg_bld("using old crappy leb_ver stuff");
+
+		if (v1 == v2) {
+			ubi_err("PEB %d and PEB %d have the same version %lld",
+				seb->pnum, pnum, v1);
+			return -EINVAL;
+		}
+
+		abs = v1 - v2;
+		if (abs < 0)
+			abs = -abs;
+
+		if (abs < 0x7FFFFFFF)
+			/* Non-overflow situation */
+			second_is_newer = (v2 > v1);
+		else
+			second_is_newer = (v2 < v1);
+	} else
+		/* Obviously the LEB with lower sequence counter is older */
+		second_is_newer = sqnum2 > seb->sqnum;
+
+	/*
+	 * Now we know which copy is newer. If the copy flag of the PEB with
+	 * newer version is not set, then we just return, otherwise we have to
+	 * check data CRC. For the second PEB we already have the VID header,
+	 * for the first one - we'll need to re-read it from flash.
+	 *
+	 * FIXME: this may be optimized so that we wouldn't read twice.
+	 */
+
+	if (second_is_newer) {
+		if (!vid_hdr->copy_flag) {
+			/* It is not a copy, so it is newer */
+			dbg_bld("second PEB %d is newer, copy_flag is unset",
+				pnum);
+			return 1;
+		}
+	} else {
+		pnum = seb->pnum;
+
+		vh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
+		if (!vh)
+			return -ENOMEM;
+
+		err = ubi_io_read_vid_hdr(ubi, pnum, vh, 0);
+		if (err) {
+			if (err == UBI_IO_BITFLIPS)
+				bitflips = 1;
+			else {
+				dbg_err("VID of PEB %d header is bad, but it "
+					"was OK earlier", pnum);
+				if (err > 0)
+					err = -EIO;
+
+				goto out_free_vidh;
+			}
+		}
+
+		if (!vh->copy_flag) {
+			/* It is not a copy, so it is newer */
+			dbg_bld("first PEB %d is newer, copy_flag is unset",
+				pnum);
+			err = bitflips << 1;
+			goto out_free_vidh;
+		}
+
+		vid_hdr = vh;
+	}
+
+	/* Read the data of the copy and check the CRC */
+
+	len = be32_to_cpu(vid_hdr->data_size);
+	buf = vmalloc(len);
+	if (!buf) {
+		err = -ENOMEM;
+		goto out_free_vidh;
+	}
+
+	err = ubi_io_read_data(ubi, buf, pnum, 0, len);
+	if (err && err != UBI_IO_BITFLIPS)
+		goto out_free_buf;
+
+	data_crc = be32_to_cpu(vid_hdr->data_crc);
+	crc = crc32(UBI_CRC32_INIT, buf, len);
+	if (crc != data_crc) {
+		dbg_bld("PEB %d CRC error: calculated %#08x, must be %#08x",
+			pnum, crc, data_crc);
+		corrupted = 1;
+		bitflips = 0;
+		second_is_newer = !second_is_newer;
+	} else {
+		dbg_bld("PEB %d CRC is OK", pnum);
+		bitflips = !!err;
+	}
+
+	vfree(buf);
+	ubi_free_vid_hdr(ubi, vh);
+
+	if (second_is_newer)
+		dbg_bld("second PEB %d is newer, copy_flag is set", pnum);
+	else
+		dbg_bld("first PEB %d is newer, copy_flag is set", pnum);
+
+	return second_is_newer | (bitflips << 1) | (corrupted << 2);
+
+out_free_buf:
+	vfree(buf);
+out_free_vidh:
+	ubi_free_vid_hdr(ubi, vh);
+	return err;
+}
+
+/**
+ * ubi_scan_add_used - add information about a physical eraseblock to the
+ * scanning information.
+ * @ubi: UBI device description object
+ * @si: scanning information
+ * @pnum: the physical eraseblock number
+ * @ec: erase counter
+ * @vid_hdr: the volume identifier header
+ * @bitflips: if bit-flips were detected when this physical eraseblock was read
+ *
+ * This function adds information about a used physical eraseblock to the
+ * 'used' tree of the corresponding volume. The function is rather complex
+ * because it has to handle cases when this is not the first physical
+ * eraseblock belonging to the same logical eraseblock, and the newer one has
+ * to be picked, while the older one has to be dropped. This function returns
+ * zero in case of success and a negative error code in case of failure.
+ */
+int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
+		      int pnum, int ec, const struct ubi_vid_hdr *vid_hdr,
+		      int bitflips)
+{
+	int err, vol_id, lnum;
+	uint32_t leb_ver;
+	unsigned long long sqnum;
+	struct ubi_scan_volume *sv;
+	struct ubi_scan_leb *seb;
+	struct rb_node **p, *parent = NULL;
+
+	vol_id = be32_to_cpu(vid_hdr->vol_id);
+	lnum = be32_to_cpu(vid_hdr->lnum);
+	sqnum = be64_to_cpu(vid_hdr->sqnum);
+	leb_ver = be32_to_cpu(vid_hdr->leb_ver);
+
+	dbg_bld("PEB %d, LEB %d:%d, EC %d, sqnum %llu, ver %u, bitflips %d",
+		pnum, vol_id, lnum, ec, sqnum, leb_ver, bitflips);
+
+	sv = add_volume(si, vol_id, pnum, vid_hdr);
+	if (IS_ERR(sv) < 0)
+		return PTR_ERR(sv);
+
+	if (si->max_sqnum < sqnum)
+		si->max_sqnum = sqnum;
+
+	/*
+	 * Walk the RB-tree of logical eraseblocks of volume @vol_id to look
+	 * if this is the first instance of this logical eraseblock or not.
+	 */
+	p = &sv->root.rb_node;
+	while (*p) {
+		int cmp_res;
+
+		parent = *p;
+		seb = rb_entry(parent, struct ubi_scan_leb, u.rb);
+		if (lnum != seb->lnum) {
+			if (lnum < seb->lnum)
+				p = &(*p)->rb_left;
+			else
+				p = &(*p)->rb_right;
+			continue;
+		}
+
+		/*
+		 * There is already a physical eraseblock describing the same
+		 * logical eraseblock present.
+		 */
+
+		dbg_bld("this LEB already exists: PEB %d, sqnum %llu, "
+			"LEB ver %u, EC %d", seb->pnum, seb->sqnum,
+			seb->leb_ver, seb->ec);
+
+		/*
+		 * Make sure that the logical eraseblocks have different
+		 * versions. Otherwise the image is bad.
+		 */
+		if (seb->leb_ver == leb_ver && leb_ver != 0) {
+			ubi_err("two LEBs with same version %u", leb_ver);
+			ubi_dbg_dump_seb(seb, 0);
+			ubi_dbg_dump_vid_hdr(vid_hdr);
+			return -EINVAL;
+		}
+
+		/*
+		 * Make sure that the logical eraseblocks have different
+		 * sequence numbers. Otherwise the image is bad.
+		 *
+		 * FIXME: remove 'sqnum != 0' check when leb_ver is removed.
+		 */
+		if (seb->sqnum == sqnum && sqnum != 0) {
+			ubi_err("two LEBs with same sequence number %llu",
+				sqnum);
+			ubi_dbg_dump_seb(seb, 0);
+			ubi_dbg_dump_vid_hdr(vid_hdr);
+			return -EINVAL;
+		}
+
+		/*
+		 * Now we have to drop the older one and preserve the newer
+		 * one.
+		 */
+		cmp_res = compare_lebs(ubi, seb, pnum, vid_hdr);
+		if (cmp_res < 0)
+			return cmp_res;
+
+		if (cmp_res & 1) {
+			/*
+			 * This logical eraseblock is newer then the one
+			 * found earlier.
+			 */
+			err = validate_vid_hdr(vid_hdr, sv, pnum);
+			if (err)
+				return err;
+
+			if (cmp_res & 4)
+				err = add_to_list(si, seb->pnum, seb->ec,
+						  &si->corr);
+			else
+				err = add_to_list(si, seb->pnum, seb->ec,
+						  &si->erase);
+			if (err)
+				return err;
+
+			seb->ec = ec;
+			seb->pnum = pnum;
+			seb->scrub = ((cmp_res & 2) || bitflips);
+			seb->sqnum = sqnum;
+			seb->leb_ver = leb_ver;
+
+			if (sv->highest_lnum == lnum)
+				sv->last_data_size =
+					be32_to_cpu(vid_hdr->data_size);
+
+			return 0;
+		} else {
+			/*
+			 * This logical eraseblock is older then the one found
+			 * previously.
+			 */
+			if (cmp_res & 4)
+				return add_to_list(si, pnum, ec, &si->corr);
+			else
+				return add_to_list(si, pnum, ec, &si->erase);
+		}
+	}
+
+	/*
+	 * We've met this logical eraseblock for the first time, add it to the
+	 * scanning information.
+	 */
+
+	err = validate_vid_hdr(vid_hdr, sv, pnum);
+	if (err)
+		return err;
+
+	seb = kmalloc(sizeof(struct ubi_scan_leb), GFP_KERNEL);
+	if (!seb)
+		return -ENOMEM;
+
+	seb->ec = ec;
+	seb->pnum = pnum;
+	seb->lnum = lnum;
+	seb->sqnum = sqnum;
+	seb->scrub = bitflips;
+	seb->leb_ver = leb_ver;
+
+	if (sv->highest_lnum <= lnum) {
+		sv->highest_lnum = lnum;
+		sv->last_data_size = be32_to_cpu(vid_hdr->data_size);
+	}
+
+	sv->leb_count += 1;
+	rb_link_node(&seb->u.rb, parent, p);
+	rb_insert_color(&seb->u.rb, &sv->root);
+	return 0;
+}
+
+/**
+ * ubi_scan_find_sv - find information about a particular volume in the
+ * scanning information.
+ * @si: scanning information
+ * @vol_id: the requested volume ID
+ *
+ * This function returns a pointer to the volume description or %NULL if there
+ * are no data about this volume in the scanning information.
+ */
+struct ubi_scan_volume *ubi_scan_find_sv(const struct ubi_scan_info *si,
+					 int vol_id)
+{
+	struct ubi_scan_volume *sv;
+	struct rb_node *p = si->volumes.rb_node;
+
+	while (p) {
+		sv = rb_entry(p, struct ubi_scan_volume, rb);
+
+		if (vol_id == sv->vol_id)
+			return sv;
+
+		if (vol_id > sv->vol_id)
+			p = p->rb_left;
+		else
+			p = p->rb_right;
+	}
+
+	return NULL;
+}
+
+/**
+ * ubi_scan_find_seb - find information about a particular logical
+ * eraseblock in the volume scanning information.
+ * @sv: a pointer to the volume scanning information
+ * @lnum: the requested logical eraseblock
+ *
+ * This function returns a pointer to the scanning logical eraseblock or %NULL
+ * if there are no data about it in the scanning volume information.
+ */
+struct ubi_scan_leb *ubi_scan_find_seb(const struct ubi_scan_volume *sv,
+				       int lnum)
+{
+	struct ubi_scan_leb *seb;
+	struct rb_node *p = sv->root.rb_node;
+
+	while (p) {
+		seb = rb_entry(p, struct ubi_scan_leb, u.rb);
+
+		if (lnum == seb->lnum)
+			return seb;
+
+		if (lnum > seb->lnum)
+			p = p->rb_left;
+		else
+			p = p->rb_right;
+	}
+
+	return NULL;
+}
+
+/**
+ * ubi_scan_rm_volume - delete scanning information about a volume.
+ * @si: scanning information
+ * @sv: the volume scanning information to delete
+ */
+void ubi_scan_rm_volume(struct ubi_scan_info *si, struct ubi_scan_volume *sv)
+{
+	struct rb_node *rb;
+	struct ubi_scan_leb *seb;
+
+	dbg_bld("remove scanning information about volume %d", sv->vol_id);
+
+	while ((rb = rb_first(&sv->root))) {
+		seb = rb_entry(rb, struct ubi_scan_leb, u.rb);
+		rb_erase(&seb->u.rb, &sv->root);
+		list_add_tail(&seb->u.list, &si->erase);
+	}
+
+	rb_erase(&sv->rb, &si->volumes);
+	kfree(sv);
+	si->vols_found -= 1;
+}
+
+/**
+ * ubi_scan_erase_peb - erase a physical eraseblock.
+ * @ubi: UBI device description object
+ * @si: scanning information
+ * @pnum: physical eraseblock number to erase;
+ * @ec: erase counter value to write (%UBI_SCAN_UNKNOWN_EC if it is unknown)
+ *
+ * This function erases physical eraseblock 'pnum', and writes the erase
+ * counter header to it. This function should only be used on UBI device
+ * initialization stages, when the EBA unit had not been yet initialized. This
+ * function returns zero in case of success and a negative error code in case
+ * of failure.
+ */
+int ubi_scan_erase_peb(struct ubi_device *ubi, const struct ubi_scan_info *si,
+		       int pnum, int ec)
+{
+	int err;
+	struct ubi_ec_hdr *ec_hdr;
+
+	if ((long long)ec >= UBI_MAX_ERASECOUNTER) {
+		/*
+		 * Erase counter overflow. Upgrade UBI and use 64-bit
+		 * erase counters internally.
+		 */
+		ubi_err("erase counter overflow at PEB %d, EC %d", pnum, ec);
+		return -EINVAL;
+	}
+
+	ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
+	if (!ec_hdr)
+		return -ENOMEM;
+
+	ec_hdr->ec = cpu_to_be64(ec);
+
+	err = ubi_io_sync_erase(ubi, pnum, 0);
+	if (err < 0)
+		goto out_free;
+
+	err = ubi_io_write_ec_hdr(ubi, pnum, ec_hdr);
+
+out_free:
+	kfree(ec_hdr);
+	return err;
+}
+
+/**
+ * ubi_scan_get_free_peb - get a free physical eraseblock.
+ * @ubi: UBI device description object
+ * @si: scanning information
+ *
+ * This function returns a free physical eraseblock. It is supposed to be
+ * called on the UBI initialization stages when the wear-leveling unit is not
+ * initialized yet. This function picks a physical eraseblocks from one of the
+ * lists, writes the EC header if it is needed, and removes it from the list.
+ *
+ * This function returns scanning physical eraseblock information in case of
+ * success and an error code in case of failure.
+ */
+struct ubi_scan_leb *ubi_scan_get_free_peb(struct ubi_device *ubi,
+					   struct ubi_scan_info *si)
+{
+	int err = 0, i;
+	struct ubi_scan_leb *seb;
+
+	if (!list_empty(&si->free)) {
+		seb = list_entry(si->free.next, struct ubi_scan_leb, u.list);
+		list_del(&seb->u.list);
+		dbg_bld("return free PEB %d, EC %d", seb->pnum, seb->ec);
+		return seb;
+	}
+
+	for (i = 0; i < 2; i++) {
+		struct list_head *head;
+		struct ubi_scan_leb *tmp_seb;
+
+		if (i == 0)
+			head = &si->erase;
+		else
+			head = &si->corr;
+
+		/*
+		 * We try to erase the first physical eraseblock from the @head
+		 * list and pick it if we succeed, or try to erase the
+		 * next one if not. And so forth. We don't want to take care
+		 * about bad eraseblocks here - they'll be handled later.
+		 */
+		list_for_each_entry_safe(seb, tmp_seb, head, u.list) {
+			if (seb->ec == UBI_SCAN_UNKNOWN_EC)
+				seb->ec = si->mean_ec;
+
+			err = ubi_scan_erase_peb(ubi, si, seb->pnum, seb->ec+1);
+			if (err)
+				continue;
+
+			seb->ec += 1;
+			list_del(&seb->u.list);
+			dbg_bld("return PEB %d, EC %d", seb->pnum, seb->ec);
+			return seb;
+		}
+	}
+
+	ubi_err("no eraseblocks found");
+	return ERR_PTR(-ENOSPC);
+}
+
+/**
+ * process_eb - read UBI headers, check them and add corresponding data
+ * to the scanning information.
+ * @ubi: UBI device description object
+ * @si: scanning information
+ * @pnum: the physical eraseblock number
+ *
+ * This function returns a zero if the physical eraseblock was successfully
+ * handled and a negative error code in case of failure.
+ */
+static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si, int pnum)
+{
+	long long uninitialized_var(ec);
+	int err, bitflips = 0, vol_id, ec_corr = 0;
+
+	dbg_bld("scan PEB %d", pnum);
+
+	/* Skip bad physical eraseblocks */
+	err = ubi_io_is_bad(ubi, pnum);
+	if (err < 0)
+		return err;
+	else if (err) {
+		/*
+		 * FIXME: this is actually duty of the I/O unit to initialize
+		 * this, but MTD does not provide enough information.
+		 */
+		si->bad_peb_count += 1;
+		return 0;
+	}
+
+	err = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
+	if (err < 0)
+		return err;
+	else if (err == UBI_IO_BITFLIPS)
+		bitflips = 1;
+	else if (err == UBI_IO_PEB_EMPTY)
+		return add_to_list(si, pnum, UBI_SCAN_UNKNOWN_EC, &si->erase);
+	else if (err == UBI_IO_BAD_EC_HDR) {
+		/*
+		 * We have to also look at the VID header, possibly it is not
+		 * corrupted. Set %bitflips flag in order to make this PEB be
+		 * moved and EC be re-created.
+		 */
+		ec_corr = 1;
+		ec = UBI_SCAN_UNKNOWN_EC;
+		bitflips = 1;
+	}
+
+	si->is_empty = 0;
+
+	if (!ec_corr) {
+		/* Make sure UBI version is OK */
+		if (ech->version != UBI_VERSION) {
+			ubi_err("this UBI version is %d, image version is %d",
+				UBI_VERSION, (int)ech->version);
+			return -EINVAL;
+		}
+
+		ec = be64_to_cpu(ech->ec);
+		if (ec > UBI_MAX_ERASECOUNTER) {
+			/*
+			 * Erase counter overflow. The EC headers have 64 bits
+			 * reserved, but we anyway make use of only 31 bit
+			 * values, as this seems to be enough for any existing
+			 * flash. Upgrade UBI and use 64-bit erase counters
+			 * internally.
+			 */
+			ubi_err("erase counter overflow, max is %d",
+				UBI_MAX_ERASECOUNTER);
+			ubi_dbg_dump_ec_hdr(ech);
+			return -EINVAL;
+		}
+	}
+
+	/* OK, we've done with the EC header, let's look at the VID header */
+
+	err = ubi_io_read_vid_hdr(ubi, pnum, vidh, 0);
+	if (err < 0)
+		return err;
+	else if (err == UBI_IO_BITFLIPS)
+		bitflips = 1;
+	else if (err == UBI_IO_BAD_VID_HDR ||
+		 (err == UBI_IO_PEB_FREE && ec_corr)) {
+		/* VID header is corrupted */
+		err = add_to_list(si, pnum, ec, &si->corr);
+		if (err)
+			return err;
+		goto adjust_mean_ec;
+	} else if (err == UBI_IO_PEB_FREE) {
+		/* No VID header - the physical eraseblock is free */
+		err = add_to_list(si, pnum, ec, &si->free);
+		if (err)
+			return err;
+		goto adjust_mean_ec;
+	}
+
+	vol_id = be32_to_cpu(vidh->vol_id);
+	if (vol_id > UBI_MAX_VOLUMES && vol_id != UBI_LAYOUT_VOLUME_ID) {
+		int lnum = be32_to_cpu(vidh->lnum);
+
+		/* Unsupported internal volume */
+		switch (vidh->compat) {
+		case UBI_COMPAT_DELETE:
+			ubi_msg("\"delete\" compatible internal volume %d:%d"
+				" found, remove it", vol_id, lnum);
+			err = add_to_list(si, pnum, ec, &si->corr);
+			if (err)
+				return err;
+			break;
+
+		case UBI_COMPAT_RO:
+			ubi_msg("read-only compatible internal volume %d:%d"
+				" found, switch to read-only mode",
+				vol_id, lnum);
+			ubi->ro_mode = 1;
+			break;
+
+		case UBI_COMPAT_PRESERVE:
+			ubi_msg("\"preserve\" compatible internal volume %d:%d"
+				" found", vol_id, lnum);
+			err = add_to_list(si, pnum, ec, &si->alien);
+			if (err)
+				return err;
+			si->alien_peb_count += 1;
+			return 0;
+
+		case UBI_COMPAT_REJECT:
+			ubi_err("incompatible internal volume %d:%d found",
+				vol_id, lnum);
+			return -EINVAL;
+		}
+	}
+
+	/* Both UBI headers seem to be fine */
+	err = ubi_scan_add_used(ubi, si, pnum, ec, vidh, bitflips);
+	if (err)
+		return err;
+
+adjust_mean_ec:
+	if (!ec_corr) {
+		si->ec_sum += ec;
+		si->ec_count += 1;
+		if (ec > si->max_ec)
+			si->max_ec = ec;
+		if (ec < si->min_ec)
+			si->min_ec = ec;
+	}
+
+	return 0;
+}
+
+/**
+ * ubi_scan - scan an MTD device.
+ * @ubi: UBI device description object
+ *
+ * This function does full scanning of an MTD device and returns complete
+ * information about it. In case of failure, an error code is returned.
+ */
+struct ubi_scan_info *ubi_scan(struct ubi_device *ubi)
+{
+	int err, pnum;
+	struct rb_node *rb1, *rb2;
+	struct ubi_scan_volume *sv;
+	struct ubi_scan_leb *seb;
+	struct ubi_scan_info *si;
+
+	si = kzalloc(sizeof(struct ubi_scan_info), GFP_KERNEL);
+	if (!si)
+		return ERR_PTR(-ENOMEM);
+
+	INIT_LIST_HEAD(&si->corr);
+	INIT_LIST_HEAD(&si->free);
+	INIT_LIST_HEAD(&si->erase);
+	INIT_LIST_HEAD(&si->alien);
+	si->volumes = RB_ROOT;
+	si->is_empty = 1;
+
+	err = -ENOMEM;
+	ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
+	if (!ech)
+		goto out_si;
+
+	vidh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
+	if (!vidh)
+		goto out_ech;
+
+	for (pnum = 0; pnum < ubi->peb_count; pnum++) {
+		cond_resched();
+
+		dbg_msg("process PEB %d", pnum);
+		err = process_eb(ubi, si, pnum);
+		if (err < 0)
+			goto out_vidh;
+	}
+
+	dbg_msg("scanning is finished");
+
+	/* Calculate mean erase counter */
+	if (si->ec_count) {
+		do_div(si->ec_sum, si->ec_count);
+		si->mean_ec = si->ec_sum;
+	}
+
+	if (si->is_empty)
+		ubi_msg("empty MTD device detected");
+
+	/*
+	 * In case of unknown erase counter we use the mean erase counter
+	 * value.
+	 */
+	ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
+		ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb)
+			if (seb->ec == UBI_SCAN_UNKNOWN_EC)
+				seb->ec = si->mean_ec;
+	}
+
+	list_for_each_entry(seb, &si->free, u.list) {
+		if (seb->ec == UBI_SCAN_UNKNOWN_EC)
+			seb->ec = si->mean_ec;
+	}
+
+	list_for_each_entry(seb, &si->corr, u.list)
+		if (seb->ec == UBI_SCAN_UNKNOWN_EC)
+			seb->ec = si->mean_ec;
+
+	list_for_each_entry(seb, &si->erase, u.list)
+		if (seb->ec == UBI_SCAN_UNKNOWN_EC)
+			seb->ec = si->mean_ec;
+
+	err = paranoid_check_si(ubi, si);
+	if (err) {
+		if (err > 0)
+			err = -EINVAL;
+		goto out_vidh;
+	}
+
+	ubi_free_vid_hdr(ubi, vidh);
+	kfree(ech);
+
+	return si;
+
+out_vidh:
+	ubi_free_vid_hdr(ubi, vidh);
+out_ech:
+	kfree(ech);
+out_si:
+	ubi_scan_destroy_si(si);
+	return ERR_PTR(err);
+}
+
+/**
+ * destroy_sv - free the scanning volume information
+ * @sv: scanning volume information
+ *
+ * This function destroys the volume RB-tree (@sv->root) and the scanning
+ * volume information.
+ */
+static void destroy_sv(struct ubi_scan_volume *sv)
+{
+	struct ubi_scan_leb *seb;
+	struct rb_node *this = sv->root.rb_node;
+
+	while (this) {
+		if (this->rb_left)
+			this = this->rb_left;
+		else if (this->rb_right)
+			this = this->rb_right;
+		else {
+			seb = rb_entry(this, struct ubi_scan_leb, u.rb);
+			this = rb_parent(this);
+			if (this) {
+				if (this->rb_left == &seb->u.rb)
+					this->rb_left = NULL;
+				else
+					this->rb_right = NULL;
+			}
+
+			kfree(seb);
+		}
+	}
+	kfree(sv);
+}
+
+/**
+ * ubi_scan_destroy_si - destroy scanning information.
+ * @si: scanning information
+ */
+void ubi_scan_destroy_si(struct ubi_scan_info *si)
+{
+	struct ubi_scan_leb *seb, *seb_tmp;
+	struct ubi_scan_volume *sv;
+	struct rb_node *rb;
+
+	list_for_each_entry_safe(seb, seb_tmp, &si->alien, u.list) {
+		list_del(&seb->u.list);
+		kfree(seb);
+	}
+	list_for_each_entry_safe(seb, seb_tmp, &si->erase, u.list) {
+		list_del(&seb->u.list);
+		kfree(seb);
+	}
+	list_for_each_entry_safe(seb, seb_tmp, &si->corr, u.list) {
+		list_del(&seb->u.list);
+		kfree(seb);
+	}
+	list_for_each_entry_safe(seb, seb_tmp, &si->free, u.list) {
+		list_del(&seb->u.list);
+		kfree(seb);
+	}
+
+	/* Destroy the volume RB-tree */
+	rb = si->volumes.rb_node;
+	while (rb) {
+		if (rb->rb_left)
+			rb = rb->rb_left;
+		else if (rb->rb_right)
+			rb = rb->rb_right;
+		else {
+			sv = rb_entry(rb, struct ubi_scan_volume, rb);
+
+			rb = rb_parent(rb);
+			if (rb) {
+				if (rb->rb_left == &sv->rb)
+					rb->rb_left = NULL;
+				else
+					rb->rb_right = NULL;
+			}
+
+			destroy_sv(sv);
+		}
+	}
+
+	kfree(si);
+}
+
+#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
+
+/**
+ * paranoid_check_si - check if the scanning information is correct and
+ * consistent.
+ * @ubi: UBI device description object
+ * @si: scanning information
+ *
+ * This function returns zero if the scanning information is all right, %1 if
+ * not and a negative error code if an error occurred.
+ */
+static int paranoid_check_si(struct ubi_device *ubi, struct ubi_scan_info *si)
+{
+	int pnum, err, vols_found = 0;
+	struct rb_node *rb1, *rb2;
+	struct ubi_scan_volume *sv;
+	struct ubi_scan_leb *seb, *last_seb;
+	uint8_t *buf;
+
+	/*
+	 * At first, check that scanning information is OK.
+	 */
+	ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
+		int leb_count = 0;
+
+		cond_resched();
+
+		vols_found += 1;
+
+		if (si->is_empty) {
+			ubi_err("bad is_empty flag");
+			goto bad_sv;
+		}
+
+		if (sv->vol_id < 0 || sv->highest_lnum < 0 ||
+		    sv->leb_count < 0 || sv->vol_type < 0 || sv->used_ebs < 0 ||
+		    sv->data_pad < 0 || sv->last_data_size < 0) {
+			ubi_err("negative values");
+			goto bad_sv;
+		}
+
+		if (sv->vol_id >= UBI_MAX_VOLUMES &&
+		    sv->vol_id < UBI_INTERNAL_VOL_START) {
+			ubi_err("bad vol_id");
+			goto bad_sv;
+		}
+
+		if (sv->vol_id > si->highest_vol_id) {
+			ubi_err("highest_vol_id is %d, but vol_id %d is there",
+				si->highest_vol_id, sv->vol_id);
+			goto out;
+		}
+
+		if (sv->vol_type != UBI_DYNAMIC_VOLUME &&
+		    sv->vol_type != UBI_STATIC_VOLUME) {
+			ubi_err("bad vol_type");
+			goto bad_sv;
+		}
+
+		if (sv->data_pad > ubi->leb_size / 2) {
+			ubi_err("bad data_pad");
+			goto bad_sv;
+		}
+
+		last_seb = NULL;
+		ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) {
+			cond_resched();
+
+			last_seb = seb;
+			leb_count += 1;
+
+			if (seb->pnum < 0 || seb->ec < 0) {
+				ubi_err("negative values");
+				goto bad_seb;
+			}
+
+			if (seb->ec < si->min_ec) {
+				ubi_err("bad si->min_ec (%d), %d found",
+					si->min_ec, seb->ec);
+				goto bad_seb;
+			}
+
+			if (seb->ec > si->max_ec) {
+				ubi_err("bad si->max_ec (%d), %d found",
+					si->max_ec, seb->ec);
+				goto bad_seb;
+			}
+
+			if (seb->pnum >= ubi->peb_count) {
+				ubi_err("too high PEB number %d, total PEBs %d",
+					seb->pnum, ubi->peb_count);
+				goto bad_seb;
+			}
+
+			if (sv->vol_type == UBI_STATIC_VOLUME) {
+				if (seb->lnum >= sv->used_ebs) {
+					ubi_err("bad lnum or used_ebs");
+					goto bad_seb;
+				}
+			} else {
+				if (sv->used_ebs != 0) {
+					ubi_err("non-zero used_ebs");
+					goto bad_seb;
+				}
+			}
+
+			if (seb->lnum > sv->highest_lnum) {
+				ubi_err("incorrect highest_lnum or lnum");
+				goto bad_seb;
+			}
+		}
+
+		if (sv->leb_count != leb_count) {
+			ubi_err("bad leb_count, %d objects in the tree",
+				leb_count);
+			goto bad_sv;
+		}
+
+		if (!last_seb)
+			continue;
+
+		seb = last_seb;
+
+		if (seb->lnum != sv->highest_lnum) {
+			ubi_err("bad highest_lnum");
+			goto bad_seb;
+		}
+	}
+
+	if (vols_found != si->vols_found) {
+		ubi_err("bad si->vols_found %d, should be %d",
+			si->vols_found, vols_found);
+		goto out;
+	}
+
+	/* Check that scanning information is correct */
+	ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
+		last_seb = NULL;
+		ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) {
+			int vol_type;
+
+			cond_resched();
+
+			last_seb = seb;
+
+			err = ubi_io_read_vid_hdr(ubi, seb->pnum, vidh, 1);
+			if (err && err != UBI_IO_BITFLIPS) {
+				ubi_err("VID header is not OK (%d)", err);
+				if (err > 0)
+					err = -EIO;
+				return err;
+			}
+
+			vol_type = vidh->vol_type == UBI_VID_DYNAMIC ?
+				   UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME;
+			if (sv->vol_type != vol_type) {
+				ubi_err("bad vol_type");
+				goto bad_vid_hdr;
+			}
+
+			if (seb->sqnum != be64_to_cpu(vidh->sqnum)) {
+				ubi_err("bad sqnum %llu", seb->sqnum);
+				goto bad_vid_hdr;
+			}
+
+			if (sv->vol_id != be32_to_cpu(vidh->vol_id)) {
+				ubi_err("bad vol_id %d", sv->vol_id);
+				goto bad_vid_hdr;
+			}
+
+			if (sv->compat != vidh->compat) {
+				ubi_err("bad compat %d", vidh->compat);
+				goto bad_vid_hdr;
+			}
+
+			if (seb->lnum != be32_to_cpu(vidh->lnum)) {
+				ubi_err("bad lnum %d", seb->lnum);
+				goto bad_vid_hdr;
+			}
+
+			if (sv->used_ebs != be32_to_cpu(vidh->used_ebs)) {
+				ubi_err("bad used_ebs %d", sv->used_ebs);
+				goto bad_vid_hdr;
+			}
+
+			if (sv->data_pad != be32_to_cpu(vidh->data_pad)) {
+				ubi_err("bad data_pad %d", sv->data_pad);
+				goto bad_vid_hdr;
+			}
+
+			if (seb->leb_ver != be32_to_cpu(vidh->leb_ver)) {
+				ubi_err("bad leb_ver %u", seb->leb_ver);
+				goto bad_vid_hdr;
+			}
+		}
+
+		if (!last_seb)
+			continue;
+
+		if (sv->highest_lnum != be32_to_cpu(vidh->lnum)) {
+			ubi_err("bad highest_lnum %d", sv->highest_lnum);
+			goto bad_vid_hdr;
+		}
+
+		if (sv->last_data_size != be32_to_cpu(vidh->data_size)) {
+			ubi_err("bad last_data_size %d", sv->last_data_size);
+			goto bad_vid_hdr;
+		}
+	}
+
+	/*
+	 * Make sure that all the physical eraseblocks are in one of the lists
+	 * or trees.
+	 */
+	buf = kzalloc(ubi->peb_count, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	for (pnum = 0; pnum < ubi->peb_count; pnum++) {
+		err = ubi_io_is_bad(ubi, pnum);
+		if (err < 0) {
+			kfree(buf);
+			return err;
+		}
+		else if (err)
+			buf[pnum] = 1;
+	}
+
+	ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb)
+		ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb)
+			buf[seb->pnum] = 1;
+
+	list_for_each_entry(seb, &si->free, u.list)
+		buf[seb->pnum] = 1;
+
+	list_for_each_entry(seb, &si->corr, u.list)
+		buf[seb->pnum] = 1;
+
+	list_for_each_entry(seb, &si->erase, u.list)
+		buf[seb->pnum] = 1;
+
+	list_for_each_entry(seb, &si->alien, u.list)
+		buf[seb->pnum] = 1;
+
+	err = 0;
+	for (pnum = 0; pnum < ubi->peb_count; pnum++)
+		if (!buf[pnum]) {
+			ubi_err("PEB %d is not referred", pnum);
+			err = 1;
+		}
+
+	kfree(buf);
+	if (err)
+		goto out;
+	return 0;
+
+bad_seb:
+	ubi_err("bad scanning information about LEB %d", seb->lnum);
+	ubi_dbg_dump_seb(seb, 0);
+	ubi_dbg_dump_sv(sv);
+	goto out;
+
+bad_sv:
+	ubi_err("bad scanning information about volume %d", sv->vol_id);
+	ubi_dbg_dump_sv(sv);
+	goto out;
+
+bad_vid_hdr:
+	ubi_err("bad scanning information about volume %d", sv->vol_id);
+	ubi_dbg_dump_sv(sv);
+	ubi_dbg_dump_vid_hdr(vidh);
+
+out:
+	ubi_dbg_dump_stack();
+	return 1;
+}
+
+#endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */
diff --git a/drivers/mtd/ubi/scan.h b/drivers/mtd/ubi/scan.h
new file mode 100644
index 0000000..966b9b6
--- /dev/null
+++ b/drivers/mtd/ubi/scan.h
@@ -0,0 +1,165 @@
+/*
+ * Copyright (c) International Business Machines Corp., 2006
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Author: Artem Bityutskiy (Битюцкий Артём)
+ */
+
+#ifndef __UBI_SCAN_H__
+#define __UBI_SCAN_H__
+
+/* The erase counter value for this physical eraseblock is unknown */
+#define UBI_SCAN_UNKNOWN_EC (-1)
+
+/**
+ * struct ubi_scan_leb - scanning information about a physical eraseblock.
+ * @ec: erase counter (%UBI_SCAN_UNKNOWN_EC if it is unknown)
+ * @pnum: physical eraseblock number
+ * @lnum: logical eraseblock number
+ * @scrub: if this physical eraseblock needs scrubbing
+ * @sqnum: sequence number
+ * @u: unions RB-tree or @list links
+ * @u.rb: link in the per-volume RB-tree of &struct ubi_scan_leb objects
+ * @u.list: link in one of the eraseblock lists
+ * @leb_ver: logical eraseblock version (obsolete)
+ *
+ * One object of this type is allocated for each physical eraseblock during
+ * scanning.
+ */
+struct ubi_scan_leb {
+	int ec;
+	int pnum;
+	int lnum;
+	int scrub;
+	unsigned long long sqnum;
+	union {
+		struct rb_node rb;
+		struct list_head list;
+	} u;
+	uint32_t leb_ver;
+};
+
+/**
+ * struct ubi_scan_volume - scanning information about a volume.
+ * @vol_id: volume ID
+ * @highest_lnum: highest logical eraseblock number in this volume
+ * @leb_count: number of logical eraseblocks in this volume
+ * @vol_type: volume type
+ * @used_ebs: number of used logical eraseblocks in this volume (only for
+ * static volumes)
+ * @last_data_size: amount of data in the last logical eraseblock of this
+ * volume (always equivalent to the usable logical eraseblock size in case of
+ * dynamic volumes)
+ * @data_pad: how many bytes at the end of logical eraseblocks of this volume
+ * are not used (due to volume alignment)
+ * @compat: compatibility flags of this volume
+ * @rb: link in the volume RB-tree
+ * @root: root of the RB-tree containing all the eraseblock belonging to this
+ * volume (&struct ubi_scan_leb objects)
+ *
+ * One object of this type is allocated for each volume during scanning.
+ */
+struct ubi_scan_volume {
+	int vol_id;
+	int highest_lnum;
+	int leb_count;
+	int vol_type;
+	int used_ebs;
+	int last_data_size;
+	int data_pad;
+	int compat;
+	struct rb_node rb;
+	struct rb_root root;
+};
+
+/**
+ * struct ubi_scan_info - UBI scanning information.
+ * @volumes: root of the volume RB-tree
+ * @corr: list of corrupted physical eraseblocks
+ * @free: list of free physical eraseblocks
+ * @erase: list of physical eraseblocks which have to be erased
+ * @alien: list of physical eraseblocks which should not be used by UBI (e.g.,
+ * @bad_peb_count: count of bad physical eraseblocks
+ * those belonging to "preserve"-compatible internal volumes)
+ * @vols_found: number of volumes found during scanning
+ * @highest_vol_id: highest volume ID
+ * @alien_peb_count: count of physical eraseblocks in the @alien list
+ * @is_empty: flag indicating whether the MTD device is empty or not
+ * @min_ec: lowest erase counter value
+ * @max_ec: highest erase counter value
+ * @max_sqnum: highest sequence number value
+ * @mean_ec: mean erase counter value
+ * @ec_sum: a temporary variable used when calculating @mean_ec
+ * @ec_count: a temporary variable used when calculating @mean_ec
+ *
+ * This data structure contains the result of scanning and may be used by other
+ * UBI units to build final UBI data structures, further error-recovery and so
+ * on.
+ */
+struct ubi_scan_info {
+	struct rb_root volumes;
+	struct list_head corr;
+	struct list_head free;
+	struct list_head erase;
+	struct list_head alien;
+	int bad_peb_count;
+	int vols_found;
+	int highest_vol_id;
+	int alien_peb_count;
+	int is_empty;
+	int min_ec;
+	int max_ec;
+	unsigned long long max_sqnum;
+	int mean_ec;
+	uint64_t ec_sum;
+	int ec_count;
+};
+
+struct ubi_device;
+struct ubi_vid_hdr;
+
+/*
+ * ubi_scan_move_to_list - move a physical eraseblock from the volume tree to a
+ * list.
+ *
+ * @sv: volume scanning information
+ * @seb: scanning eraseblock infprmation
+ * @list: the list to move to
+ */
+static inline void ubi_scan_move_to_list(struct ubi_scan_volume *sv,
+					 struct ubi_scan_leb *seb,
+					 struct list_head *list)
+{
+		rb_erase(&seb->u.rb, &sv->root);
+		list_add_tail(&seb->u.list, list);
+}
+
+int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
+		      int pnum, int ec, const struct ubi_vid_hdr *vid_hdr,
+		      int bitflips);
+struct ubi_scan_volume *ubi_scan_find_sv(const struct ubi_scan_info *si,
+					 int vol_id);
+struct ubi_scan_leb *ubi_scan_find_seb(const struct ubi_scan_volume *sv,
+				       int lnum);
+void ubi_scan_rm_volume(struct ubi_scan_info *si, struct ubi_scan_volume *sv);
+struct ubi_scan_leb *ubi_scan_get_free_peb(struct ubi_device *ubi,
+					   struct ubi_scan_info *si);
+int ubi_scan_erase_peb(struct ubi_device *ubi, const struct ubi_scan_info *si,
+		       int pnum, int ec);
+struct ubi_scan_info *ubi_scan(struct ubi_device *ubi);
+void ubi_scan_destroy_si(struct ubi_scan_info *si);
+
+#endif /* !__UBI_SCAN_H__ */
diff --git a/drivers/mtd/ubi/ubi-media.h b/drivers/mtd/ubi/ubi-media.h
new file mode 100644
index 0000000..c3185d9
--- /dev/null
+++ b/drivers/mtd/ubi/ubi-media.h
@@ -0,0 +1,372 @@
+/*
+ * Copyright (c) International Business Machines Corp., 2006
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём)
+ *          Thomas Gleixner
+ *          Frank Haverkamp
+ *          Oliver Lohmann
+ *          Andreas Arnez
+ */
+
+/*
+ * This file defines the layout of UBI headers and all the other UBI on-flash
+ * data structures.
+ */
+
+#ifndef __UBI_MEDIA_H__
+#define __UBI_MEDIA_H__
+
+#include <asm/byteorder.h>
+
+/* The version of UBI images supported by this implementation */
+#define UBI_VERSION 1
+
+/* The highest erase counter value supported by this implementation */
+#define UBI_MAX_ERASECOUNTER 0x7FFFFFFF
+
+/* The initial CRC32 value used when calculating CRC checksums */
+#define UBI_CRC32_INIT 0xFFFFFFFFU
+
+/* Erase counter header magic number (ASCII "UBI#") */
+#define UBI_EC_HDR_MAGIC  0x55424923
+/* Volume identifier header magic number (ASCII "UBI!") */
+#define UBI_VID_HDR_MAGIC 0x55424921
+
+/*
+ * Volume type constants used in the volume identifier header.
+ *
+ * @UBI_VID_DYNAMIC: dynamic volume
+ * @UBI_VID_STATIC: static volume
+ */
+enum {
+	UBI_VID_DYNAMIC = 1,
+	UBI_VID_STATIC  = 2
+};
+
+/*
+ * Volume flags used in the volume table record.
+ *
+ * @UBI_VTBL_AUTORESIZE_FLG: auto-resize this volume
+ *
+ * %UBI_VTBL_AUTORESIZE_FLG flag can be set only for one volume in the volume
+ * table. UBI automatically re-sizes the volume which has this flag and makes
+ * the volume to be of largest possible size. This means that if after the
+ * initialization UBI finds out that there are available physical eraseblocks
+ * present on the device, it automatically appends all of them to the volume
+ * (the physical eraseblocks reserved for bad eraseblocks handling and other
+ * reserved physical eraseblocks are not taken). So, if there is a volume with
+ * the %UBI_VTBL_AUTORESIZE_FLG flag set, the amount of available logical
+ * eraseblocks will be zero after UBI is loaded, because all of them will be
+ * reserved for this volume. Note, the %UBI_VTBL_AUTORESIZE_FLG bit is cleared
+ * after the volume had been initialized.
+ *
+ * The auto-resize feature is useful for device production purposes. For
+ * example, different NAND flash chips may have different amount of initial bad
+ * eraseblocks, depending of particular chip instance. Manufacturers of NAND
+ * chips usually guarantee that the amount of initial bad eraseblocks does not
+ * exceed certain percent, e.g. 2%. When one creates an UBI image which will be
+ * flashed to the end devices in production, he does not know the exact amount
+ * of good physical eraseblocks the NAND chip on the device will have, but this
+ * number is required to calculate the volume sized and put them to the volume
+ * table of the UBI image. In this case, one of the volumes (e.g., the one
+ * which will store the root file system) is marked as "auto-resizable", and
+ * UBI will adjust its size on the first boot if needed.
+ *
+ * Note, first UBI reserves some amount of physical eraseblocks for bad
+ * eraseblock handling, and then re-sizes the volume, not vice-versa. This
+ * means that the pool of reserved physical eraseblocks will always be present.
+ */
+enum {
+	UBI_VTBL_AUTORESIZE_FLG = 0x01,
+};
+
+/*
+ * Compatibility constants used by internal volumes.
+ *
+ * @UBI_COMPAT_DELETE: delete this internal volume before anything is written
+ * to the flash
+ * @UBI_COMPAT_RO: attach this device in read-only mode
+ * @UBI_COMPAT_PRESERVE: preserve this internal volume - do not touch its
+ * physical eraseblocks, don't allow the wear-leveling unit to move them
+ * @UBI_COMPAT_REJECT: reject this UBI image
+ */
+enum {
+	UBI_COMPAT_DELETE   = 1,
+	UBI_COMPAT_RO       = 2,
+	UBI_COMPAT_PRESERVE = 4,
+	UBI_COMPAT_REJECT   = 5
+};
+
+/* Sizes of UBI headers */
+#define UBI_EC_HDR_SIZE  sizeof(struct ubi_ec_hdr)
+#define UBI_VID_HDR_SIZE sizeof(struct ubi_vid_hdr)
+
+/* Sizes of UBI headers without the ending CRC */
+#define UBI_EC_HDR_SIZE_CRC  (UBI_EC_HDR_SIZE  - sizeof(__be32))
+#define UBI_VID_HDR_SIZE_CRC (UBI_VID_HDR_SIZE - sizeof(__be32))
+
+/**
+ * struct ubi_ec_hdr - UBI erase counter header.
+ * @magic: erase counter header magic number (%UBI_EC_HDR_MAGIC)
+ * @version: version of UBI implementation which is supposed to accept this
+ * UBI image
+ * @padding1: reserved for future, zeroes
+ * @ec: the erase counter
+ * @vid_hdr_offset: where the VID header starts
+ * @data_offset: where the user data start
+ * @padding2: reserved for future, zeroes
+ * @hdr_crc: erase counter header CRC checksum
+ *
+ * The erase counter header takes 64 bytes and has a plenty of unused space for
+ * future usage. The unused fields are zeroed. The @version field is used to
+ * indicate the version of UBI implementation which is supposed to be able to
+ * work with this UBI image. If @version is greater then the current UBI
+ * version, the image is rejected. This may be useful in future if something
+ * is changed radically. This field is duplicated in the volume identifier
+ * header.
+ *
+ * The @vid_hdr_offset and @data_offset fields contain the offset of the the
+ * volume identifier header and user data, relative to the beginning of the
+ * physical eraseblock. These values have to be the same for all physical
+ * eraseblocks.
+ */
+struct ubi_ec_hdr {
+	__be32  magic;
+	__u8    version;
+	__u8    padding1[3];
+	__be64  ec; /* Warning: the current limit is 31-bit anyway! */
+	__be32  vid_hdr_offset;
+	__be32  data_offset;
+	__u8    padding2[36];
+	__be32  hdr_crc;
+} __attribute__ ((packed));
+
+/**
+ * struct ubi_vid_hdr - on-flash UBI volume identifier header.
+ * @magic: volume identifier header magic number (%UBI_VID_HDR_MAGIC)
+ * @version: UBI implementation version which is supposed to accept this UBI
+ * image (%UBI_VERSION)
+ * @vol_type: volume type (%UBI_VID_DYNAMIC or %UBI_VID_STATIC)
+ * @copy_flag: if this logical eraseblock was copied from another physical
+ * eraseblock (for wear-leveling reasons)
+ * @compat: compatibility of this volume (%0, %UBI_COMPAT_DELETE,
+ * %UBI_COMPAT_IGNORE, %UBI_COMPAT_PRESERVE, or %UBI_COMPAT_REJECT)
+ * @vol_id: ID of this volume
+ * @lnum: logical eraseblock number
+ * @leb_ver: version of this logical eraseblock (IMPORTANT: obsolete, to be
+ * removed, kept only for not breaking older UBI users)
+ * @data_size: how many bytes of data this logical eraseblock contains
+ * @used_ebs: total number of used logical eraseblocks in this volume
+ * @data_pad: how many bytes at the end of this physical eraseblock are not
+ * used
+ * @data_crc: CRC checksum of the data stored in this logical eraseblock
+ * @padding1: reserved for future, zeroes
+ * @sqnum: sequence number
+ * @padding2: reserved for future, zeroes
+ * @hdr_crc: volume identifier header CRC checksum
+ *
+ * The @sqnum is the value of the global sequence counter at the time when this
+ * VID header was created. The global sequence counter is incremented each time
+ * UBI writes a new VID header to the flash, i.e. when it maps a logical
+ * eraseblock to a new physical eraseblock. The global sequence counter is an
+ * unsigned 64-bit integer and we assume it never overflows. The @sqnum
+ * (sequence number) is used to distinguish between older and newer versions of
+ * logical eraseblocks.
+ *
+ * There are 2 situations when there may be more then one physical eraseblock
+ * corresponding to the same logical eraseblock, i.e., having the same @vol_id
+ * and @lnum values in the volume identifier header. Suppose we have a logical
+ * eraseblock L and it is mapped to the physical eraseblock P.
+ *
+ * 1. Because UBI may erase physical eraseblocks asynchronously, the following
+ * situation is possible: L is asynchronously erased, so P is scheduled for
+ * erasure, then L is written to,i.e. mapped to another physical eraseblock P1,
+ * so P1 is written to, then an unclean reboot happens. Result - there are 2
+ * physical eraseblocks P and P1 corresponding to the same logical eraseblock
+ * L. But P1 has greater sequence number, so UBI picks P1 when it attaches the
+ * flash.
+ *
+ * 2. From time to time UBI moves logical eraseblocks to other physical
+ * eraseblocks for wear-leveling reasons. If, for example, UBI moves L from P
+ * to P1, and an unclean reboot happens before P is physically erased, there
+ * are two physical eraseblocks P and P1 corresponding to L and UBI has to
+ * select one of them when the flash is attached. The @sqnum field says which
+ * PEB is the original (obviously P will have lower @sqnum) and the copy. But
+ * it is not enough to select the physical eraseblock with the higher sequence
+ * number, because the unclean reboot could have happen in the middle of the
+ * copying process, so the data in P is corrupted. It is also not enough to
+ * just select the physical eraseblock with lower sequence number, because the
+ * data there may be old (consider a case if more data was added to P1 after
+ * the copying). Moreover, the unclean reboot may happen when the erasure of P
+ * was just started, so it result in unstable P, which is "mostly" OK, but
+ * still has unstable bits.
+ *
+ * UBI uses the @copy_flag field to indicate that this logical eraseblock is a
+ * copy. UBI also calculates data CRC when the data is moved and stores it at
+ * the @data_crc field of the copy (P1). So when UBI needs to pick one physical
+ * eraseblock of two (P or P1), the @copy_flag of the newer one (P1) is
+ * examined. If it is cleared, the situation* is simple and the newer one is
+ * picked. If it is set, the data CRC of the copy (P1) is examined. If the CRC
+ * checksum is correct, this physical eraseblock is selected (P1). Otherwise
+ * the older one (P) is selected.
+ *
+ * Note, there is an obsolete @leb_ver field which was used instead of @sqnum
+ * in the past. But it is not used anymore and we keep it in order to be able
+ * to deal with old UBI images. It will be removed at some point.
+ *
+ * There are 2 sorts of volumes in UBI: user volumes and internal volumes.
+ * Internal volumes are not seen from outside and are used for various internal
+ * UBI purposes. In this implementation there is only one internal volume - the
+ * layout volume. Internal volumes are the main mechanism of UBI extensions.
+ * For example, in future one may introduce a journal internal volume. Internal
+ * volumes have their own reserved range of IDs.
+ *
+ * The @compat field is only used for internal volumes and contains the "degree
+ * of their compatibility". It is always zero for user volumes. This field
+ * provides a mechanism to introduce UBI extensions and to be still compatible
+ * with older UBI binaries. For example, if someone introduced a journal in
+ * future, he would probably use %UBI_COMPAT_DELETE compatibility for the
+ * journal volume.  And in this case, older UBI binaries, which know nothing
+ * about the journal volume, would just delete this volume and work perfectly
+ * fine. This is similar to what Ext2fs does when it is fed by an Ext3fs image
+ * - it just ignores the Ext3fs journal.
+ *
+ * The @data_crc field contains the CRC checksum of the contents of the logical
+ * eraseblock if this is a static volume. In case of dynamic volumes, it does
+ * not contain the CRC checksum as a rule. The only exception is when the
+ * data of the physical eraseblock was moved by the wear-leveling unit, then
+ * the wear-leveling unit calculates the data CRC and stores it in the
+ * @data_crc field. And of course, the @copy_flag is %in this case.
+ *
+ * The @data_size field is used only for static volumes because UBI has to know
+ * how many bytes of data are stored in this eraseblock. For dynamic volumes,
+ * this field usually contains zero. The only exception is when the data of the
+ * physical eraseblock was moved to another physical eraseblock for
+ * wear-leveling reasons. In this case, UBI calculates CRC checksum of the
+ * contents and uses both @data_crc and @data_size fields. In this case, the
+ * @data_size field contains data size.
+ *
+ * The @used_ebs field is used only for static volumes and indicates how many
+ * eraseblocks the data of the volume takes. For dynamic volumes this field is
+ * not used and always contains zero.
+ *
+ * The @data_pad is calculated when volumes are created using the alignment
+ * parameter. So, effectively, the @data_pad field reduces the size of logical
+ * eraseblocks of this volume. This is very handy when one uses block-oriented
+ * software (say, cramfs) on top of the UBI volume.
+ */
+struct ubi_vid_hdr {
+	__be32  magic;
+	__u8    version;
+	__u8    vol_type;
+	__u8    copy_flag;
+	__u8    compat;
+	__be32  vol_id;
+	__be32  lnum;
+	__be32  leb_ver; /* obsolete, to be removed, don't use */
+	__be32  data_size;
+	__be32  used_ebs;
+	__be32  data_pad;
+	__be32  data_crc;
+	__u8    padding1[4];
+	__be64  sqnum;
+	__u8    padding2[12];
+	__be32  hdr_crc;
+} __attribute__ ((packed));
+
+/* Internal UBI volumes count */
+#define UBI_INT_VOL_COUNT 1
+
+/*
+ * Starting ID of internal volumes. There is reserved room for 4096 internal
+ * volumes.
+ */
+#define UBI_INTERNAL_VOL_START (0x7FFFFFFF - 4096)
+
+/* The layout volume contains the volume table */
+
+#define UBI_LAYOUT_VOLUME_ID     UBI_INTERNAL_VOL_START
+#define UBI_LAYOUT_VOLUME_TYPE   UBI_VID_DYNAMIC
+#define UBI_LAYOUT_VOLUME_ALIGN  1
+#define UBI_LAYOUT_VOLUME_EBS    2
+#define UBI_LAYOUT_VOLUME_NAME   "layout volume"
+#define UBI_LAYOUT_VOLUME_COMPAT UBI_COMPAT_REJECT
+
+/* The maximum number of volumes per one UBI device */
+#define UBI_MAX_VOLUMES 128
+
+/* The maximum volume name length */
+#define UBI_VOL_NAME_MAX 127
+
+/* Size of the volume table record */
+#define UBI_VTBL_RECORD_SIZE sizeof(struct ubi_vtbl_record)
+
+/* Size of the volume table record without the ending CRC */
+#define UBI_VTBL_RECORD_SIZE_CRC (UBI_VTBL_RECORD_SIZE - sizeof(__be32))
+
+/**
+ * struct ubi_vtbl_record - a record in the volume table.
+ * @reserved_pebs: how many physical eraseblocks are reserved for this volume
+ * @alignment: volume alignment
+ * @data_pad: how many bytes are unused at the end of the each physical
+ * eraseblock to satisfy the requested alignment
+ * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
+ * @upd_marker: if volume update was started but not finished
+ * @name_len: volume name length
+ * @name: the volume name
+ * @flags: volume flags (%UBI_VTBL_AUTORESIZE_FLG)
+ * @padding: reserved, zeroes
+ * @crc: a CRC32 checksum of the record
+ *
+ * The volume table records are stored in the volume table, which is stored in
+ * the layout volume. The layout volume consists of 2 logical eraseblock, each
+ * of which contains a copy of the volume table (i.e., the volume table is
+ * duplicated). The volume table is an array of &struct ubi_vtbl_record
+ * objects indexed by the volume ID.
+ *
+ * If the size of the logical eraseblock is large enough to fit
+ * %UBI_MAX_VOLUMES records, the volume table contains %UBI_MAX_VOLUMES
+ * records. Otherwise, it contains as many records as it can fit (i.e., size of
+ * logical eraseblock divided by sizeof(struct ubi_vtbl_record)).
+ *
+ * The @upd_marker flag is used to implement volume update. It is set to %1
+ * before update and set to %0 after the update. So if the update operation was
+ * interrupted, UBI knows that the volume is corrupted.
+ *
+ * The @alignment field is specified when the volume is created and cannot be
+ * later changed. It may be useful, for example, when a block-oriented file
+ * system works on top of UBI. The @data_pad field is calculated using the
+ * logical eraseblock size and @alignment. The alignment must be multiple to the
+ * minimal flash I/O unit. If @alignment is 1, all the available space of
+ * the physical eraseblocks is used.
+ *
+ * Empty records contain all zeroes and the CRC checksum of those zeroes.
+ */
+struct ubi_vtbl_record {
+	__be32  reserved_pebs;
+	__be32  alignment;
+	__be32  data_pad;
+	__u8    vol_type;
+	__u8    upd_marker;
+	__be16  name_len;
+	__u8    name[UBI_VOL_NAME_MAX+1];
+	__u8    flags;
+	__u8    padding[23];
+	__be32  crc;
+} __attribute__ ((packed));
+
+#endif /* !__UBI_MEDIA_H__ */
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
new file mode 100644
index 0000000..bf77a15
--- /dev/null
+++ b/drivers/mtd/ubi/ubi.h
@@ -0,0 +1,641 @@
+/*
+ * Copyright (c) International Business Machines Corp., 2006
+ * Copyright (c) Nokia Corporation, 2006, 2007
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Author: Artem Bityutskiy (Битюцкий Артём)
+ */
+
+#ifndef __UBI_UBI_H__
+#define __UBI_UBI_H__
+
+#ifdef UBI_LINUX
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/rbtree.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/mutex.h>
+#include <linux/rwsem.h>
+#include <linux/spinlock.h>
+#include <linux/fs.h>
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/string.h>
+#include <linux/vmalloc.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/ubi.h>
+#endif
+
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/rbtree.h>
+#include <linux/string.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/ubi.h>
+
+#include "ubi-media.h"
+#include "scan.h"
+#include "debug.h"
+
+/* Maximum number of supported UBI devices */
+#define UBI_MAX_DEVICES 32
+
+/* UBI name used for character devices, sysfs, etc */
+#define UBI_NAME_STR "ubi"
+
+/* Normal UBI messages */
+#define ubi_msg(fmt, ...) printk(KERN_NOTICE "UBI: " fmt "\n", ##__VA_ARGS__)
+/* UBI warning messages */
+#define ubi_warn(fmt, ...) printk(KERN_WARNING "UBI warning: %s: " fmt "\n", \
+				  __func__, ##__VA_ARGS__)
+/* UBI error messages */
+#define ubi_err(fmt, ...) printk(KERN_ERR "UBI error: %s: " fmt "\n", \
+				 __func__, ##__VA_ARGS__)
+
+/* Lowest number PEBs reserved for bad PEB handling */
+#define MIN_RESEVED_PEBS 2
+
+/* Background thread name pattern */
+#define UBI_BGT_NAME_PATTERN "ubi_bgt%dd"
+
+/* This marker in the EBA table means that the LEB is um-mapped */
+#define UBI_LEB_UNMAPPED -1
+
+/*
+ * In case of errors, UBI tries to repeat the operation several times before
+ * returning error. The below constant defines how many times UBI re-tries.
+ */
+#define UBI_IO_RETRIES 3
+
+/*
+ * Error codes returned by the I/O unit.
+ *
+ * UBI_IO_PEB_EMPTY: the physical eraseblock is empty, i.e. it contains only
+ * 0xFF bytes
+ * UBI_IO_PEB_FREE: the physical eraseblock is free, i.e. it contains only a
+ * valid erase counter header, and the rest are %0xFF bytes
+ * UBI_IO_BAD_EC_HDR: the erase counter header is corrupted (bad magic or CRC)
+ * UBI_IO_BAD_VID_HDR: the volume identifier header is corrupted (bad magic or
+ * CRC)
+ * UBI_IO_BITFLIPS: bit-flips were detected and corrected
+ */
+enum {
+	UBI_IO_PEB_EMPTY = 1,
+	UBI_IO_PEB_FREE,
+	UBI_IO_BAD_EC_HDR,
+	UBI_IO_BAD_VID_HDR,
+	UBI_IO_BITFLIPS
+};
+
+/**
+ * struct ubi_wl_entry - wear-leveling entry.
+ * @rb: link in the corresponding RB-tree
+ * @ec: erase counter
+ * @pnum: physical eraseblock number
+ *
+ * This data structure is used in the WL unit. Each physical eraseblock has a
+ * corresponding &struct wl_entry object which may be kept in different
+ * RB-trees. See WL unit for details.
+ */
+struct ubi_wl_entry {
+	struct rb_node rb;
+	int ec;
+	int pnum;
+};
+
+/**
+ * struct ubi_ltree_entry - an entry in the lock tree.
+ * @rb: links RB-tree nodes
+ * @vol_id: volume ID of the locked logical eraseblock
+ * @lnum: locked logical eraseblock number
+ * @users: how many tasks are using this logical eraseblock or wait for it
+ * @mutex: read/write mutex to implement read/write access serialization to
+ *         the (@vol_id, @lnum) logical eraseblock
+ *
+ * This data structure is used in the EBA unit to implement per-LEB locking.
+ * When a logical eraseblock is being locked - corresponding
+ * &struct ubi_ltree_entry object is inserted to the lock tree (@ubi->ltree).
+ * See EBA unit for details.
+ */
+struct ubi_ltree_entry {
+	struct rb_node rb;
+	int vol_id;
+	int lnum;
+	int users;
+	struct rw_semaphore mutex;
+};
+
+struct ubi_volume_desc;
+
+/**
+ * struct ubi_volume - UBI volume description data structure.
+ * @dev: device object to make use of the the Linux device model
+ * @cdev: character device object to create character device
+ * @ubi: reference to the UBI device description object
+ * @vol_id: volume ID
+ * @ref_count: volume reference count
+ * @readers: number of users holding this volume in read-only mode
+ * @writers: number of users holding this volume in read-write mode
+ * @exclusive: whether somebody holds this volume in exclusive mode
+ *
+ * @reserved_pebs: how many physical eraseblocks are reserved for this volume
+ * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
+ * @usable_leb_size: logical eraseblock size without padding
+ * @used_ebs: how many logical eraseblocks in this volume contain data
+ * @last_eb_bytes: how many bytes are stored in the last logical eraseblock
+ * @used_bytes: how many bytes of data this volume contains
+ * @alignment: volume alignment
+ * @data_pad: how many bytes are not used at the end of physical eraseblocks to
+ *            satisfy the requested alignment
+ * @name_len: volume name length
+ * @name: volume name
+ *
+ * @upd_ebs: how many eraseblocks are expected to be updated
+ * @ch_lnum: LEB number which is being changing by the atomic LEB change
+ *           operation
+ * @ch_dtype: data persistency type which is being changing by the atomic LEB
+ *            change operation
+ * @upd_bytes: how many bytes are expected to be received for volume update or
+ *             atomic LEB change
+ * @upd_received: how many bytes were already received for volume update or
+ *                atomic LEB change
+ * @upd_buf: update buffer which is used to collect update data or data for
+ *           atomic LEB change
+ *
+ * @eba_tbl: EBA table of this volume (LEB->PEB mapping)
+ * @checked: %1 if this static volume was checked
+ * @corrupted: %1 if the volume is corrupted (static volumes only)
+ * @upd_marker: %1 if the update marker is set for this volume
+ * @updating: %1 if the volume is being updated
+ * @changing_leb: %1 if the atomic LEB change ioctl command is in progress
+ *
+ * @gluebi_desc: gluebi UBI volume descriptor
+ * @gluebi_refcount: reference count of the gluebi MTD device
+ * @gluebi_mtd: MTD device description object of the gluebi MTD device
+ *
+ * The @corrupted field indicates that the volume's contents is corrupted.
+ * Since UBI protects only static volumes, this field is not relevant to
+ * dynamic volumes - it is user's responsibility to assure their data
+ * integrity.
+ *
+ * The @upd_marker flag indicates that this volume is either being updated at
+ * the moment or is damaged because of an unclean reboot.
+ */
+struct ubi_volume {
+	struct device dev;
+	struct cdev cdev;
+	struct ubi_device *ubi;
+	int vol_id;
+	int ref_count;
+	int readers;
+	int writers;
+	int exclusive;
+
+	int reserved_pebs;
+	int vol_type;
+	int usable_leb_size;
+	int used_ebs;
+	int last_eb_bytes;
+	long long used_bytes;
+	int alignment;
+	int data_pad;
+	int name_len;
+	char name[UBI_VOL_NAME_MAX+1];
+
+	int upd_ebs;
+	int ch_lnum;
+	int ch_dtype;
+	long long upd_bytes;
+	long long upd_received;
+	void *upd_buf;
+
+	int *eba_tbl;
+	unsigned int checked:1;
+	unsigned int corrupted:1;
+	unsigned int upd_marker:1;
+	unsigned int updating:1;
+	unsigned int changing_leb:1;
+
+#ifdef CONFIG_MTD_UBI_GLUEBI
+	/*
+	 * Gluebi-related stuff may be compiled out.
+	 * TODO: this should not be built into UBI but should be a separate
+	 * ubimtd driver which works on top of UBI and emulates MTD devices.
+	 */
+	struct ubi_volume_desc *gluebi_desc;
+	int gluebi_refcount;
+	struct mtd_info gluebi_mtd;
+#endif
+};
+
+/**
+ * struct ubi_volume_desc - descriptor of the UBI volume returned when it is
+ * opened.
+ * @vol: reference to the corresponding volume description object
+ * @mode: open mode (%UBI_READONLY, %UBI_READWRITE, or %UBI_EXCLUSIVE)
+ */
+struct ubi_volume_desc {
+	struct ubi_volume *vol;
+	int mode;
+};
+
+struct ubi_wl_entry;
+
+/**
+ * struct ubi_device - UBI device description structure
+ * @dev: UBI device object to use the the Linux device model
+ * @cdev: character device object to create character device
+ * @ubi_num: UBI device number
+ * @ubi_name: UBI device name
+ * @vol_count: number of volumes in this UBI device
+ * @volumes: volumes of this UBI device
+ * @volumes_lock: protects @volumes, @rsvd_pebs, @avail_pebs, beb_rsvd_pebs,
+ *                @beb_rsvd_level, @bad_peb_count, @good_peb_count, @vol_count,
+ *                @vol->readers, @vol->writers, @vol->exclusive,
+ *                @vol->ref_count, @vol->mapping and @vol->eba_tbl.
+ * @ref_count: count of references on the UBI device
+ *
+ * @rsvd_pebs: count of reserved physical eraseblocks
+ * @avail_pebs: count of available physical eraseblocks
+ * @beb_rsvd_pebs: how many physical eraseblocks are reserved for bad PEB
+ *                 handling
+ * @beb_rsvd_level: normal level of PEBs reserved for bad PEB handling
+ *
+ * @autoresize_vol_id: ID of the volume which has to be auto-resized at the end
+ *                     of UBI ititializetion
+ * @vtbl_slots: how many slots are available in the volume table
+ * @vtbl_size: size of the volume table in bytes
+ * @vtbl: in-RAM volume table copy
+ * @volumes_mutex: protects on-flash volume table and serializes volume
+ *                 changes, like creation, deletion, update, resize
+ *
+ * @max_ec: current highest erase counter value
+ * @mean_ec: current mean erase counter value
+ *
+ * @global_sqnum: global sequence number
+ * @ltree_lock: protects the lock tree and @global_sqnum
+ * @ltree: the lock tree
+ * @alc_mutex: serializes "atomic LEB change" operations
+ *
+ * @used: RB-tree of used physical eraseblocks
+ * @free: RB-tree of free physical eraseblocks
+ * @scrub: RB-tree of physical eraseblocks which need scrubbing
+ * @prot: protection trees
+ * @prot.pnum: protection tree indexed by physical eraseblock numbers
+ * @prot.aec: protection tree indexed by absolute erase counter value
+ * @wl_lock: protects the @used, @free, @prot, @lookuptbl, @abs_ec, @move_from,
+ *           @move_to, @move_to_put @erase_pending, @wl_scheduled, and @works
+ *           fields
+ * @move_mutex: serializes eraseblock moves
+ * @wl_scheduled: non-zero if the wear-leveling was scheduled
+ * @lookuptbl: a table to quickly find a &struct ubi_wl_entry object for any
+ *             physical eraseblock
+ * @abs_ec: absolute erase counter
+ * @move_from: physical eraseblock from where the data is being moved
+ * @move_to: physical eraseblock where the data is being moved to
+ * @move_to_put: if the "to" PEB was put
+ * @works: list of pending works
+ * @works_count: count of pending works
+ * @bgt_thread: background thread description object
+ * @thread_enabled: if the background thread is enabled
+ * @bgt_name: background thread name
+ *
+ * @flash_size: underlying MTD device size (in bytes)
+ * @peb_count: count of physical eraseblocks on the MTD device
+ * @peb_size: physical eraseblock size
+ * @bad_peb_count: count of bad physical eraseblocks
+ * @good_peb_count: count of good physical eraseblocks
+ * @min_io_size: minimal input/output unit size of the underlying MTD device
+ * @hdrs_min_io_size: minimal I/O unit size used for VID and EC headers
+ * @ro_mode: if the UBI device is in read-only mode
+ * @leb_size: logical eraseblock size
+ * @leb_start: starting offset of logical eraseblocks within physical
+ * eraseblocks
+ * @ec_hdr_alsize: size of the EC header aligned to @hdrs_min_io_size
+ * @vid_hdr_alsize: size of the VID header aligned to @hdrs_min_io_size
+ * @vid_hdr_offset: starting offset of the volume identifier header (might be
+ * unaligned)
+ * @vid_hdr_aloffset: starting offset of the VID header aligned to
+ * @hdrs_min_io_size
+ * @vid_hdr_shift: contains @vid_hdr_offset - @vid_hdr_aloffset
+ * @bad_allowed: whether the MTD device admits of bad physical eraseblocks or
+ *               not
+ * @mtd: MTD device descriptor
+ *
+ * @peb_buf1: a buffer of PEB size used for different purposes
+ * @peb_buf2: another buffer of PEB size used for different purposes
+ * @buf_mutex: proptects @peb_buf1 and @peb_buf2
+ * @dbg_peb_buf: buffer of PEB size used for debugging
+ * @dbg_buf_mutex: proptects @dbg_peb_buf
+ */
+struct ubi_device {
+	struct cdev cdev;
+	struct device dev;
+	int ubi_num;
+	char ubi_name[sizeof(UBI_NAME_STR)+5];
+	int vol_count;
+	struct ubi_volume *volumes[UBI_MAX_VOLUMES+UBI_INT_VOL_COUNT];
+	spinlock_t volumes_lock;
+	int ref_count;
+
+	int rsvd_pebs;
+	int avail_pebs;
+	int beb_rsvd_pebs;
+	int beb_rsvd_level;
+
+	int autoresize_vol_id;
+	int vtbl_slots;
+	int vtbl_size;
+	struct ubi_vtbl_record *vtbl;
+	struct mutex volumes_mutex;
+
+	int max_ec;
+	/* TODO: mean_ec is not updated run-time, fix */
+	int mean_ec;
+
+	/* EBA unit's stuff */
+	unsigned long long global_sqnum;
+	spinlock_t ltree_lock;
+	struct rb_root ltree;
+	struct mutex alc_mutex;
+
+	/* Wear-leveling unit's stuff */
+	struct rb_root used;
+	struct rb_root free;
+	struct rb_root scrub;
+	struct {
+		struct rb_root pnum;
+		struct rb_root aec;
+	} prot;
+	spinlock_t wl_lock;
+	struct mutex move_mutex;
+	struct rw_semaphore work_sem;
+	int wl_scheduled;
+	struct ubi_wl_entry **lookuptbl;
+	unsigned long long abs_ec;
+	struct ubi_wl_entry *move_from;
+	struct ubi_wl_entry *move_to;
+	int move_to_put;
+	struct list_head works;
+	int works_count;
+	struct task_struct *bgt_thread;
+	int thread_enabled;
+	char bgt_name[sizeof(UBI_BGT_NAME_PATTERN)+2];
+
+	/* I/O unit's stuff */
+	long long flash_size;
+	int peb_count;
+	int peb_size;
+	int bad_peb_count;
+	int good_peb_count;
+	int min_io_size;
+	int hdrs_min_io_size;
+	int ro_mode;
+	int leb_size;
+	int leb_start;
+	int ec_hdr_alsize;
+	int vid_hdr_alsize;
+	int vid_hdr_offset;
+	int vid_hdr_aloffset;
+	int vid_hdr_shift;
+	int bad_allowed;
+	struct mtd_info *mtd;
+
+	void *peb_buf1;
+	void *peb_buf2;
+	struct mutex buf_mutex;
+	struct mutex ckvol_mutex;
+#ifdef CONFIG_MTD_UBI_DEBUG
+	void *dbg_peb_buf;
+	struct mutex dbg_buf_mutex;
+#endif
+};
+
+extern struct kmem_cache *ubi_wl_entry_slab;
+extern struct file_operations ubi_ctrl_cdev_operations;
+extern struct file_operations ubi_cdev_operations;
+extern struct file_operations ubi_vol_cdev_operations;
+extern struct class *ubi_class;
+extern struct mutex ubi_devices_mutex;
+
+/* vtbl.c */
+int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
+			   struct ubi_vtbl_record *vtbl_rec);
+int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_scan_info *si);
+
+/* vmt.c */
+int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req);
+int ubi_remove_volume(struct ubi_volume_desc *desc);
+int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs);
+int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol);
+void ubi_free_volume(struct ubi_device *ubi, struct ubi_volume *vol);
+
+/* upd.c */
+int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol,
+		     long long bytes);
+int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol,
+			 const void __user *buf, int count);
+int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
+			 const struct ubi_leb_change_req *req);
+int ubi_more_leb_change_data(struct ubi_device *ubi, struct ubi_volume *vol,
+			     const void __user *buf, int count);
+
+/* misc.c */
+int ubi_calc_data_len(const struct ubi_device *ubi, const void *buf, int length);
+int ubi_check_volume(struct ubi_device *ubi, int vol_id);
+void ubi_calculate_reserved(struct ubi_device *ubi);
+
+/* gluebi.c */
+#ifdef CONFIG_MTD_UBI_GLUEBI
+int ubi_create_gluebi(struct ubi_device *ubi, struct ubi_volume *vol);
+int ubi_destroy_gluebi(struct ubi_volume *vol);
+void ubi_gluebi_updated(struct ubi_volume *vol);
+#else
+#define ubi_create_gluebi(ubi, vol) 0
+#define ubi_destroy_gluebi(vol) 0
+#define ubi_gluebi_updated(vol)
+#endif
+
+/* eba.c */
+int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol,
+		      int lnum);
+int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
+		     void *buf, int offset, int len, int check);
+int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
+		      const void *buf, int offset, int len, int dtype);
+int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
+			 int lnum, const void *buf, int len, int dtype,
+			 int used_ebs);
+int ubi_eba_atomic_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
+			      int lnum, const void *buf, int len, int dtype);
+int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
+		     struct ubi_vid_hdr *vid_hdr);
+int ubi_eba_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si);
+void ubi_eba_close(const struct ubi_device *ubi);
+
+/* wl.c */
+int ubi_wl_get_peb(struct ubi_device *ubi, int dtype);
+int ubi_wl_put_peb(struct ubi_device *ubi, int pnum, int torture);
+int ubi_wl_flush(struct ubi_device *ubi);
+int ubi_wl_scrub_peb(struct ubi_device *ubi, int pnum);
+int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si);
+void ubi_wl_close(struct ubi_device *ubi);
+int ubi_thread(void *u);
+
+/* io.c */
+int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
+		int len);
+int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
+		 int len);
+int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture);
+int ubi_io_is_bad(const struct ubi_device *ubi, int pnum);
+int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum);
+int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
+		       struct ubi_ec_hdr *ec_hdr, int verbose);
+int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
+			struct ubi_ec_hdr *ec_hdr);
+int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
+			struct ubi_vid_hdr *vid_hdr, int verbose);
+int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
+			 struct ubi_vid_hdr *vid_hdr);
+
+/* build.c */
+int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset);
+int ubi_detach_mtd_dev(int ubi_num, int anyway);
+struct ubi_device *ubi_get_device(int ubi_num);
+void ubi_put_device(struct ubi_device *ubi);
+struct ubi_device *ubi_get_by_major(int major);
+int ubi_major2num(int major);
+
+/*
+ * ubi_rb_for_each_entry - walk an RB-tree.
+ * @rb: a pointer to type 'struct rb_node' to to use as a loop counter
+ * @pos: a pointer to RB-tree entry type to use as a loop counter
+ * @root: RB-tree's root
+ * @member: the name of the 'struct rb_node' within the RB-tree entry
+ */
+#define ubi_rb_for_each_entry(rb, pos, root, member)                         \
+	for (rb = rb_first(root),                                            \
+	     pos = (rb ? container_of(rb, typeof(*pos), member) : NULL);     \
+	     rb;                                                             \
+	     rb = rb_next(rb), pos = container_of(rb, typeof(*pos), member))
+
+/**
+ * ubi_zalloc_vid_hdr - allocate a volume identifier header object.
+ * @ubi: UBI device description object
+ * @gfp_flags: GFP flags to allocate with
+ *
+ * This function returns a pointer to the newly allocated and zero-filled
+ * volume identifier header object in case of success and %NULL in case of
+ * failure.
+ */
+static inline struct ubi_vid_hdr *
+ubi_zalloc_vid_hdr(const struct ubi_device *ubi, gfp_t gfp_flags)
+{
+	void *vid_hdr;
+
+	vid_hdr = kzalloc(ubi->vid_hdr_alsize, gfp_flags);
+	if (!vid_hdr)
+		return NULL;
+
+	/*
+	 * VID headers may be stored at un-aligned flash offsets, so we shift
+	 * the pointer.
+	 */
+	return vid_hdr + ubi->vid_hdr_shift;
+}
+
+/**
+ * ubi_free_vid_hdr - free a volume identifier header object.
+ * @ubi: UBI device description object
+ * @vid_hdr: the object to free
+ */
+static inline void ubi_free_vid_hdr(const struct ubi_device *ubi,
+				    struct ubi_vid_hdr *vid_hdr)
+{
+	void *p = vid_hdr;
+
+	if (!p)
+		return;
+
+	kfree(p - ubi->vid_hdr_shift);
+}
+
+/*
+ * This function is equivalent to 'ubi_io_read()', but @offset is relative to
+ * the beginning of the logical eraseblock, not to the beginning of the
+ * physical eraseblock.
+ */
+static inline int ubi_io_read_data(const struct ubi_device *ubi, void *buf,
+				   int pnum, int offset, int len)
+{
+	ubi_assert(offset >= 0);
+	return ubi_io_read(ubi, buf, pnum, offset + ubi->leb_start, len);
+}
+
+/*
+ * This function is equivalent to 'ubi_io_write()', but @offset is relative to
+ * the beginning of the logical eraseblock, not to the beginning of the
+ * physical eraseblock.
+ */
+static inline int ubi_io_write_data(struct ubi_device *ubi, const void *buf,
+				    int pnum, int offset, int len)
+{
+	ubi_assert(offset >= 0);
+	return ubi_io_write(ubi, buf, pnum, offset + ubi->leb_start, len);
+}
+
+/**
+ * ubi_ro_mode - switch to read-only mode.
+ * @ubi: UBI device description object
+ */
+static inline void ubi_ro_mode(struct ubi_device *ubi)
+{
+	if (!ubi->ro_mode) {
+		ubi->ro_mode = 1;
+		ubi_warn("switch to read-only mode");
+	}
+}
+
+/**
+ * vol_id2idx - get table index by volume ID.
+ * @ubi: UBI device description object
+ * @vol_id: volume ID
+ */
+static inline int vol_id2idx(const struct ubi_device *ubi, int vol_id)
+{
+	if (vol_id >= UBI_INTERNAL_VOL_START)
+		return vol_id - UBI_INTERNAL_VOL_START + ubi->vtbl_slots;
+	else
+		return vol_id;
+}
+
+/**
+ * idx2vol_id - get volume ID by table index.
+ * @ubi: UBI device description object
+ * @idx: table index
+ */
+static inline int idx2vol_id(const struct ubi_device *ubi, int idx)
+{
+	if (idx >= ubi->vtbl_slots)
+		return idx - ubi->vtbl_slots + UBI_INTERNAL_VOL_START;
+	else
+		return idx;
+}
+
+#endif /* !__UBI_UBI_H__ */