UBI: Add basic UBI support to U-Boot (Part 3/8)

This patch adds basic UBI (Unsorted Block Image) support to U-Boot.
It's based on the Linux UBI version and basically has a "OS"
translation wrapper that defines most Linux specific calls
(spin_lock() etc.) into no-ops. Some source code parts have been
uncommented by "#ifdef UBI_LINUX". This makes it easier to compare
this version with the Linux version and simplifies future UBI
ports/bug-fixes from the Linux version.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Stefan Roese <sr@denx.de>

3 files changed, 2018 insertions, 0 deletions

diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
new file mode 100644
index 0000000..2d44f23
--- /dev/null
+++ b/drivers/mtd/ubi/io.c
@@ -0,0 +1,1274 @@
+/*
+ * 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)
+ */
+
+/*
+ * UBI input/output unit.
+ *
+ * This unit provides a uniform way to work with all kinds of the underlying
+ * MTD devices. It also implements handy functions for reading and writing UBI
+ * headers.
+ *
+ * We are trying to have a paranoid mindset and not to trust to what we read
+ * from the flash media in order to be more secure and robust. So this unit
+ * validates every single header it reads from the flash media.
+ *
+ * Some words about how the eraseblock headers are stored.
+ *
+ * The erase counter header is always stored at offset zero. By default, the
+ * VID header is stored after the EC header at the closest aligned offset
+ * (i.e. aligned to the minimum I/O unit size). Data starts next to the VID
+ * header at the closest aligned offset. But this default layout may be
+ * changed. For example, for different reasons (e.g., optimization) UBI may be
+ * asked to put the VID header at further offset, and even at an unaligned
+ * offset. Of course, if the offset of the VID header is unaligned, UBI adds
+ * proper padding in front of it. Data offset may also be changed but it has to
+ * be aligned.
+ *
+ * About minimal I/O units. In general, UBI assumes flash device model where
+ * there is only one minimal I/O unit size. E.g., in case of NOR flash it is 1,
+ * in case of NAND flash it is a NAND page, etc. This is reported by MTD in the
+ * @ubi->mtd->writesize field. But as an exception, UBI admits of using another
+ * (smaller) minimal I/O unit size for EC and VID headers to make it possible
+ * to do different optimizations.
+ *
+ * This is extremely useful in case of NAND flashes which admit of several
+ * write operations to one NAND page. In this case UBI can fit EC and VID
+ * headers at one NAND page. Thus, UBI may use "sub-page" size as the minimal
+ * I/O unit for the headers (the @ubi->hdrs_min_io_size field). But it still
+ * reports NAND page size (@ubi->min_io_size) as a minimal I/O unit for the UBI
+ * users.
+ *
+ * Example: some Samsung NANDs with 2KiB pages allow 4x 512-byte writes, so
+ * although the minimal I/O unit is 2K, UBI uses 512 bytes for EC and VID
+ * headers.
+ *
+ * Q: why not just to treat sub-page as a minimal I/O unit of this flash
+ * device, e.g., make @ubi->min_io_size = 512 in the example above?
+ *
+ * A: because when writing a sub-page, MTD still writes a full 2K page but the
+ * bytes which are no relevant to the sub-page are 0xFF. So, basically, writing
+ * 4x512 sub-pages is 4 times slower then writing one 2KiB NAND page. Thus, we
+ * prefer to use sub-pages only for EV and VID headers.
+ *
+ * As it was noted above, the VID header may start at a non-aligned offset.
+ * For example, in case of a 2KiB page NAND flash with a 512 bytes sub-page,
+ * the VID header may reside at offset 1984 which is the last 64 bytes of the
+ * last sub-page (EC header is always at offset zero). This causes some
+ * difficulties when reading and writing VID headers.
+ *
+ * Suppose we have a 64-byte buffer and we read a VID header at it. We change
+ * the data and want to write this VID header out. As we can only write in
+ * 512-byte chunks, we have to allocate one more buffer and copy our VID header
+ * to offset 448 of this buffer.
+ *
+ * The I/O unit does the following trick in order to avoid this extra copy.
+ * It always allocates a @ubi->vid_hdr_alsize bytes buffer for the VID header
+ * and returns a pointer to offset @ubi->vid_hdr_shift of this buffer. When the
+ * VID header is being written out, it shifts the VID header pointer back and
+ * writes the whole sub-page.
+ */
+
+#ifdef UBI_LINUX
+#include <linux/crc32.h>
+#include <linux/err.h>
+#endif
+
+#include <ubi_uboot.h>
+#include "ubi.h"
+
+#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
+static int paranoid_check_not_bad(const struct ubi_device *ubi, int pnum);
+static int paranoid_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum);
+static int paranoid_check_ec_hdr(const struct ubi_device *ubi, int pnum,
+				 const struct ubi_ec_hdr *ec_hdr);
+static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum);
+static int paranoid_check_vid_hdr(const struct ubi_device *ubi, int pnum,
+				  const struct ubi_vid_hdr *vid_hdr);
+static int paranoid_check_all_ff(struct ubi_device *ubi, int pnum, int offset,
+				 int len);
+#else
+#define paranoid_check_not_bad(ubi, pnum) 0
+#define paranoid_check_peb_ec_hdr(ubi, pnum)  0
+#define paranoid_check_ec_hdr(ubi, pnum, ec_hdr)  0
+#define paranoid_check_peb_vid_hdr(ubi, pnum) 0
+#define paranoid_check_vid_hdr(ubi, pnum, vid_hdr) 0
+#define paranoid_check_all_ff(ubi, pnum, offset, len) 0
+#endif
+
+/**
+ * ubi_io_read - read data from a physical eraseblock.
+ * @ubi: UBI device description object
+ * @buf: buffer where to store the read data
+ * @pnum: physical eraseblock number to read from
+ * @offset: offset within the physical eraseblock from where to read
+ * @len: how many bytes to read
+ *
+ * This function reads data from offset @offset of physical eraseblock @pnum
+ * and stores the read data in the @buf buffer. The following return codes are
+ * possible:
+ *
+ * o %0 if all the requested data were successfully read;
+ * o %UBI_IO_BITFLIPS if all the requested data were successfully read, but
+ *   correctable bit-flips were detected; this is harmless but may indicate
+ *   that this eraseblock may become bad soon (but do not have to);
+ * o %-EBADMSG if the MTD subsystem reported about data integrity problems, for
+ *   example it can be an ECC error in case of NAND; this most probably means
+ *   that the data is corrupted;
+ * o %-EIO if some I/O error occurred;
+ * o other negative error codes in case of other errors.
+ */
+int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
+		int len)
+{
+	int err, retries = 0;
+	size_t read;
+	loff_t addr;
+
+	dbg_io("read %d bytes from PEB %d:%d", len, pnum, offset);
+
+	ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
+	ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
+	ubi_assert(len > 0);
+
+	err = paranoid_check_not_bad(ubi, pnum);
+	if (err)
+		return err > 0 ? -EINVAL : err;
+
+	addr = (loff_t)pnum * ubi->peb_size + offset;
+retry:
+	err = ubi->mtd->read(ubi->mtd, addr, len, &read, buf);
+	if (err) {
+		if (err == -EUCLEAN) {
+			/*
+			 * -EUCLEAN is reported if there was a bit-flip which
+			 * was corrected, so this is harmless.
+			 */
+			ubi_msg("fixable bit-flip detected at PEB %d", pnum);
+			ubi_assert(len == read);
+			return UBI_IO_BITFLIPS;
+		}
+
+		if (read != len && retries++ < UBI_IO_RETRIES) {
+			dbg_io("error %d while reading %d bytes from PEB %d:%d, "
+			       "read only %zd bytes, retry",
+			       err, len, pnum, offset, read);
+			yield();
+			goto retry;
+		}
+
+		ubi_err("error %d while reading %d bytes from PEB %d:%d, "
+			"read %zd bytes", err, len, pnum, offset, read);
+		ubi_dbg_dump_stack();
+
+		/*
+		 * The driver should never return -EBADMSG if it failed to read
+		 * all the requested data. But some buggy drivers might do
+		 * this, so we change it to -EIO.
+		 */
+		if (read != len && err == -EBADMSG) {
+			ubi_assert(0);
+			printk("%s[%d] not here\n", __func__, __LINE__);
+//			err = -EIO;
+		}
+	} else {
+		ubi_assert(len == read);
+
+		if (ubi_dbg_is_bitflip()) {
+			dbg_msg("bit-flip (emulated)");
+			err = UBI_IO_BITFLIPS;
+		}
+	}
+
+	return err;
+}
+
+/**
+ * ubi_io_write - write data to a physical eraseblock.
+ * @ubi: UBI device description object
+ * @buf: buffer with the data to write
+ * @pnum: physical eraseblock number to write to
+ * @offset: offset within the physical eraseblock where to write
+ * @len: how many bytes to write
+ *
+ * This function writes @len bytes of data from buffer @buf to offset @offset
+ * of physical eraseblock @pnum. If all the data were successfully written,
+ * zero is returned. If an error occurred, this function returns a negative
+ * error code. If %-EIO is returned, the physical eraseblock most probably went
+ * bad.
+ *
+ * Note, in case of an error, it is possible that something was still written
+ * to the flash media, but may be some garbage.
+ */
+int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
+		 int len)
+{
+	int err;
+	size_t written;
+	loff_t addr;
+
+	dbg_io("write %d bytes to PEB %d:%d", len, pnum, offset);
+
+	ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
+	ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
+	ubi_assert(offset % ubi->hdrs_min_io_size == 0);
+	ubi_assert(len > 0 && len % ubi->hdrs_min_io_size == 0);
+
+	if (ubi->ro_mode) {
+		ubi_err("read-only mode");
+		return -EROFS;
+	}
+
+	/* The below has to be compiled out if paranoid checks are disabled */
+
+	err = paranoid_check_not_bad(ubi, pnum);
+	if (err)
+		return err > 0 ? -EINVAL : err;
+
+	/* The area we are writing to has to contain all 0xFF bytes */
+	err = paranoid_check_all_ff(ubi, pnum, offset, len);
+	if (err)
+		return err > 0 ? -EINVAL : err;
+
+	if (offset >= ubi->leb_start) {
+		/*
+		 * We write to the data area of the physical eraseblock. Make
+		 * sure it has valid EC and VID headers.
+		 */
+		err = paranoid_check_peb_ec_hdr(ubi, pnum);
+		if (err)
+			return err > 0 ? -EINVAL : err;
+		err = paranoid_check_peb_vid_hdr(ubi, pnum);
+		if (err)
+			return err > 0 ? -EINVAL : err;
+	}
+
+	if (ubi_dbg_is_write_failure()) {
+		dbg_err("cannot write %d bytes to PEB %d:%d "
+			"(emulated)", len, pnum, offset);
+		ubi_dbg_dump_stack();
+		return -EIO;
+	}
+
+	addr = (loff_t)pnum * ubi->peb_size + offset;
+	err = ubi->mtd->write(ubi->mtd, addr, len, &written, buf);
+	if (err) {
+		ubi_err("error %d while writing %d bytes to PEB %d:%d, written"
+			" %zd bytes", err, len, pnum, offset, written);
+		ubi_dbg_dump_stack();
+	} else
+		ubi_assert(written == len);
+
+	return err;
+}
+
+/**
+ * erase_callback - MTD erasure call-back.
+ * @ei: MTD erase information object.
+ *
+ * Note, even though MTD erase interface is asynchronous, all the current
+ * implementations are synchronous anyway.
+ */
+static void erase_callback(struct erase_info *ei)
+{
+	wake_up_interruptible((wait_queue_head_t *)ei->priv);
+}
+
+/**
+ * do_sync_erase - synchronously erase a physical eraseblock.
+ * @ubi: UBI device description object
+ * @pnum: the physical eraseblock number to erase
+ *
+ * This function synchronously erases physical eraseblock @pnum and returns
+ * zero in case of success and a negative error code in case of failure. If
+ * %-EIO is returned, the physical eraseblock most probably went bad.
+ */
+static int do_sync_erase(struct ubi_device *ubi, int pnum)
+{
+	int err, retries = 0;
+	struct erase_info ei;
+	wait_queue_head_t wq;
+
+	dbg_io("erase PEB %d", pnum);
+
+retry:
+	init_waitqueue_head(&wq);
+	memset(&ei, 0, sizeof(struct erase_info));
+
+	ei.mtd      = ubi->mtd;
+	ei.addr     = (loff_t)pnum * ubi->peb_size;
+	ei.len      = ubi->peb_size;
+	ei.callback = erase_callback;
+	ei.priv     = (unsigned long)&wq;
+
+	err = ubi->mtd->erase(ubi->mtd, &ei);
+	if (err) {
+		if (retries++ < UBI_IO_RETRIES) {
+			dbg_io("error %d while erasing PEB %d, retry",
+			       err, pnum);
+			yield();
+			goto retry;
+		}
+		ubi_err("cannot erase PEB %d, error %d", pnum, err);
+		ubi_dbg_dump_stack();
+		return err;
+	}
+
+	err = wait_event_interruptible(wq, ei.state == MTD_ERASE_DONE ||
+					   ei.state == MTD_ERASE_FAILED);
+	if (err) {
+		ubi_err("interrupted PEB %d erasure", pnum);
+		return -EINTR;
+	}
+
+	if (ei.state == MTD_ERASE_FAILED) {
+		if (retries++ < UBI_IO_RETRIES) {
+			dbg_io("error while erasing PEB %d, retry", pnum);
+			yield();
+			goto retry;
+		}
+		ubi_err("cannot erase PEB %d", pnum);
+		ubi_dbg_dump_stack();
+		return -EIO;
+	}
+
+	err = paranoid_check_all_ff(ubi, pnum, 0, ubi->peb_size);
+	if (err)
+		return err > 0 ? -EINVAL : err;
+
+	if (ubi_dbg_is_erase_failure() && !err) {
+		dbg_err("cannot erase PEB %d (emulated)", pnum);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/**
+ * check_pattern - check if buffer contains only a certain byte pattern.
+ * @buf: buffer to check
+ * @patt: the pattern to check
+ * @size: buffer size in bytes
+ *
+ * This function returns %1 in there are only @patt bytes in @buf, and %0 if
+ * something else was also found.
+ */
+static int check_pattern(const void *buf, uint8_t patt, int size)
+{
+	int i;
+
+	for (i = 0; i < size; i++)
+		if (((const uint8_t *)buf)[i] != patt)
+			return 0;
+	return 1;
+}
+
+/* Patterns to write to a physical eraseblock when torturing it */
+static uint8_t patterns[] = {0xa5, 0x5a, 0x0};
+
+/**
+ * torture_peb - test a supposedly bad physical eraseblock.
+ * @ubi: UBI device description object
+ * @pnum: the physical eraseblock number to test
+ *
+ * This function returns %-EIO if the physical eraseblock did not pass the
+ * test, a positive number of erase operations done if the test was
+ * successfully passed, and other negative error codes in case of other errors.
+ */
+static int torture_peb(struct ubi_device *ubi, int pnum)
+{
+	int err, i, patt_count;
+
+	patt_count = ARRAY_SIZE(patterns);
+	ubi_assert(patt_count > 0);
+
+	mutex_lock(&ubi->buf_mutex);
+	for (i = 0; i < patt_count; i++) {
+		err = do_sync_erase(ubi, pnum);
+		if (err)
+			goto out;
+
+		/* Make sure the PEB contains only 0xFF bytes */
+		err = ubi_io_read(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
+		if (err)
+			goto out;
+
+		err = check_pattern(ubi->peb_buf1, 0xFF, ubi->peb_size);
+		if (err == 0) {
+			ubi_err("erased PEB %d, but a non-0xFF byte found",
+				pnum);
+			err = -EIO;
+			goto out;
+		}
+
+		/* Write a pattern and check it */
+		memset(ubi->peb_buf1, patterns[i], ubi->peb_size);
+		err = ubi_io_write(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
+		if (err)
+			goto out;
+
+		memset(ubi->peb_buf1, ~patterns[i], ubi->peb_size);
+		err = ubi_io_read(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
+		if (err)
+			goto out;
+
+		err = check_pattern(ubi->peb_buf1, patterns[i], ubi->peb_size);
+		if (err == 0) {
+			ubi_err("pattern %x checking failed for PEB %d",
+				patterns[i], pnum);
+			err = -EIO;
+			goto out;
+		}
+	}
+
+	err = patt_count;
+
+out:
+	mutex_unlock(&ubi->buf_mutex);
+	if (err == UBI_IO_BITFLIPS || err == -EBADMSG) {
+		/*
+		 * If a bit-flip or data integrity error was detected, the test
+		 * has not passed because it happened on a freshly erased
+		 * physical eraseblock which means something is wrong with it.
+		 */
+		ubi_err("read problems on freshly erased PEB %d, must be bad",
+			pnum);
+		err = -EIO;
+	}
+	return err;
+}
+
+/**
+ * ubi_io_sync_erase - synchronously erase a physical eraseblock.
+ * @ubi: UBI device description object
+ * @pnum: physical eraseblock number to erase
+ * @torture: if this physical eraseblock has to be tortured
+ *
+ * This function synchronously erases physical eraseblock @pnum. If @torture
+ * flag is not zero, the physical eraseblock is checked by means of writing
+ * different patterns to it and reading them back. If the torturing is enabled,
+ * the physical eraseblock is erased more then once.
+ *
+ * This function returns the number of erasures made in case of success, %-EIO
+ * if the erasure failed or the torturing test failed, and other negative error
+ * codes in case of other errors. Note, %-EIO means that the physical
+ * eraseblock is bad.
+ */
+int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture)
+{
+	int err, ret = 0;
+
+	ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
+
+	err = paranoid_check_not_bad(ubi, pnum);
+	if (err != 0)
+		return err > 0 ? -EINVAL : err;
+
+	if (ubi->ro_mode) {
+		ubi_err("read-only mode");
+		return -EROFS;
+	}
+
+	if (torture) {
+		ret = torture_peb(ubi, pnum);
+		if (ret < 0)
+			return ret;
+	}
+
+	err = do_sync_erase(ubi, pnum);
+	if (err)
+		return err;
+
+	return ret + 1;
+}
+
+/**
+ * ubi_io_is_bad - check if a physical eraseblock is bad.
+ * @ubi: UBI device description object
+ * @pnum: the physical eraseblock number to check
+ *
+ * This function returns a positive number if the physical eraseblock is bad,
+ * zero if not, and a negative error code if an error occurred.
+ */
+int ubi_io_is_bad(const struct ubi_device *ubi, int pnum)
+{
+	struct mtd_info *mtd = ubi->mtd;
+
+	ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
+
+	if (ubi->bad_allowed) {
+		int ret;
+
+		ret = mtd->block_isbad(mtd, (loff_t)pnum * ubi->peb_size);
+		if (ret < 0)
+			ubi_err("error %d while checking if PEB %d is bad",
+				ret, pnum);
+		else if (ret)
+			dbg_io("PEB %d is bad", pnum);
+		return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * ubi_io_mark_bad - mark a physical eraseblock as bad.
+ * @ubi: UBI device description object
+ * @pnum: the physical eraseblock number to mark
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure.
+ */
+int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum)
+{
+	int err;
+	struct mtd_info *mtd = ubi->mtd;
+
+	ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
+
+	if (ubi->ro_mode) {
+		ubi_err("read-only mode");
+		return -EROFS;
+	}
+
+	if (!ubi->bad_allowed)
+		return 0;
+
+	err = mtd->block_markbad(mtd, (loff_t)pnum * ubi->peb_size);
+	if (err)
+		ubi_err("cannot mark PEB %d bad, error %d", pnum, err);
+	return err;
+}
+
+/**
+ * validate_ec_hdr - validate an erase counter header.
+ * @ubi: UBI device description object
+ * @ec_hdr: the erase counter header to check
+ *
+ * This function returns zero if the erase counter header is OK, and %1 if
+ * not.
+ */
+static int validate_ec_hdr(const struct ubi_device *ubi,
+			   const struct ubi_ec_hdr *ec_hdr)
+{
+	long long ec;
+	int vid_hdr_offset, leb_start;
+
+	ec = be64_to_cpu(ec_hdr->ec);
+	vid_hdr_offset = be32_to_cpu(ec_hdr->vid_hdr_offset);
+	leb_start = be32_to_cpu(ec_hdr->data_offset);
+
+	if (ec_hdr->version != UBI_VERSION) {
+		ubi_err("node with incompatible UBI version found: "
+			"this UBI version is %d, image version is %d",
+			UBI_VERSION, (int)ec_hdr->version);
+		goto bad;
+	}
+
+	if (vid_hdr_offset != ubi->vid_hdr_offset) {
+		ubi_err("bad VID header offset %d, expected %d",
+			vid_hdr_offset, ubi->vid_hdr_offset);
+		goto bad;
+	}
+
+	if (leb_start != ubi->leb_start) {
+		ubi_err("bad data offset %d, expected %d",
+			leb_start, ubi->leb_start);
+		goto bad;
+	}
+
+	if (ec < 0 || ec > UBI_MAX_ERASECOUNTER) {
+		ubi_err("bad erase counter %lld", ec);
+		goto bad;
+	}
+
+	return 0;
+
+bad:
+	ubi_err("bad EC header");
+	ubi_dbg_dump_ec_hdr(ec_hdr);
+	ubi_dbg_dump_stack();
+	return 1;
+}
+
+/**
+ * ubi_io_read_ec_hdr - read and check an erase counter header.
+ * @ubi: UBI device description object
+ * @pnum: physical eraseblock to read from
+ * @ec_hdr: a &struct ubi_ec_hdr object where to store the read erase counter
+ * header
+ * @verbose: be verbose if the header is corrupted or was not found
+ *
+ * This function reads erase counter header from physical eraseblock @pnum and
+ * stores it in @ec_hdr. This function also checks CRC checksum of the read
+ * erase counter header. The following codes may be returned:
+ *
+ * o %0 if the CRC checksum is correct and the header was successfully read;
+ * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
+ *   and corrected by the flash driver; this is harmless but may indicate that
+ *   this eraseblock may become bad soon (but may be not);
+ * o %UBI_IO_BAD_EC_HDR if the erase counter header is corrupted (a CRC error);
+ * o %UBI_IO_PEB_EMPTY if the physical eraseblock is empty;
+ * o a negative error code in case of failure.
+ */
+int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
+		       struct ubi_ec_hdr *ec_hdr, int verbose)
+{
+	int err, read_err = 0;
+	uint32_t crc, magic, hdr_crc;
+
+	dbg_io("read EC header from PEB %d", pnum);
+	ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
+	if (UBI_IO_DEBUG)
+		verbose = 1;
+
+	err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
+	if (err) {
+		if (err != UBI_IO_BITFLIPS && err != -EBADMSG)
+			return err;
+
+		/*
+		 * We read all the data, but either a correctable bit-flip
+		 * occurred, or MTD reported about some data integrity error,
+		 * like an ECC error in case of NAND. The former is harmless,
+		 * the later may mean that the read data is corrupted. But we
+		 * have a CRC check-sum and we will detect this. If the EC
+		 * header is still OK, we just report this as there was a
+		 * bit-flip.
+		 */
+		read_err = err;
+	}
+
+	magic = be32_to_cpu(ec_hdr->magic);
+	if (magic != UBI_EC_HDR_MAGIC) {
+		/*
+		 * The magic field is wrong. Let's check if we have read all
+		 * 0xFF. If yes, this physical eraseblock is assumed to be
+		 * empty.
+		 *
+		 * But if there was a read error, we do not test it for all
+		 * 0xFFs. Even if it does contain all 0xFFs, this error
+		 * indicates that something is still wrong with this physical
+		 * eraseblock and we anyway cannot treat it as empty.
+		 */
+		if (read_err != -EBADMSG &&
+		    check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) {
+			/* The physical eraseblock is supposedly empty */
+
+			/*
+			 * The below is just a paranoid check, it has to be
+			 * compiled out if paranoid checks are disabled.
+			 */
+			err = paranoid_check_all_ff(ubi, pnum, 0,
+						    ubi->peb_size);
+			if (err)
+				return err > 0 ? UBI_IO_BAD_EC_HDR : err;
+
+			if (verbose)
+				ubi_warn("no EC header found at PEB %d, "
+					 "only 0xFF bytes", pnum);
+			return UBI_IO_PEB_EMPTY;
+		}
+
+		/*
+		 * This is not a valid erase counter header, and these are not
+		 * 0xFF bytes. Report that the header is corrupted.
+		 */
+		if (verbose) {
+			ubi_warn("bad magic number at PEB %d: %08x instead of "
+				 "%08x", pnum, magic, UBI_EC_HDR_MAGIC);
+			ubi_dbg_dump_ec_hdr(ec_hdr);
+		}
+		return UBI_IO_BAD_EC_HDR;
+	}
+
+	crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
+	hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
+
+	if (hdr_crc != crc) {
+		if (verbose) {
+			ubi_warn("bad EC header CRC at PEB %d, calculated %#08x,"
+				 " read %#08x", pnum, crc, hdr_crc);
+			ubi_dbg_dump_ec_hdr(ec_hdr);
+		}
+		return UBI_IO_BAD_EC_HDR;
+	}
+
+	/* And of course validate what has just been read from the media */
+	err = validate_ec_hdr(ubi, ec_hdr);
+	if (err) {
+		ubi_err("validation failed for PEB %d", pnum);
+		return -EINVAL;
+	}
+
+	return read_err ? UBI_IO_BITFLIPS : 0;
+}
+
+/**
+ * ubi_io_write_ec_hdr - write an erase counter header.
+ * @ubi: UBI device description object
+ * @pnum: physical eraseblock to write to
+ * @ec_hdr: the erase counter header to write
+ *
+ * This function writes erase counter header described by @ec_hdr to physical
+ * eraseblock @pnum. It also fills most fields of @ec_hdr before writing, so
+ * the caller do not have to fill them. Callers must only fill the @ec_hdr->ec
+ * field.
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure. If %-EIO is returned, the physical eraseblock most probably
+ * went bad.
+ */
+int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
+			struct ubi_ec_hdr *ec_hdr)
+{
+	int err;
+	uint32_t crc;
+
+	dbg_io("write EC header to PEB %d", pnum);
+	ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
+
+	ec_hdr->magic = cpu_to_be32(UBI_EC_HDR_MAGIC);
+	ec_hdr->version = UBI_VERSION;
+	ec_hdr->vid_hdr_offset = cpu_to_be32(ubi->vid_hdr_offset);
+	ec_hdr->data_offset = cpu_to_be32(ubi->leb_start);
+	crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
+	ec_hdr->hdr_crc = cpu_to_be32(crc);
+
+	err = paranoid_check_ec_hdr(ubi, pnum, ec_hdr);
+	if (err)
+		return -EINVAL;
+
+	err = ubi_io_write(ubi, ec_hdr, pnum, 0, ubi->ec_hdr_alsize);
+	return err;
+}
+
+/**
+ * validate_vid_hdr - validate a volume identifier header.
+ * @ubi: UBI device description object
+ * @vid_hdr: the volume identifier header to check
+ *
+ * This function checks that data stored in the volume identifier header
+ * @vid_hdr. Returns zero if the VID header is OK and %1 if not.
+ */
+static int validate_vid_hdr(const struct ubi_device *ubi,
+			    const struct ubi_vid_hdr *vid_hdr)
+{
+	int vol_type = vid_hdr->vol_type;
+	int copy_flag = vid_hdr->copy_flag;
+	int vol_id = be32_to_cpu(vid_hdr->vol_id);
+	int lnum = be32_to_cpu(vid_hdr->lnum);
+	int compat = vid_hdr->compat;
+	int data_size = be32_to_cpu(vid_hdr->data_size);
+	int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
+	int data_pad = be32_to_cpu(vid_hdr->data_pad);
+	int data_crc = be32_to_cpu(vid_hdr->data_crc);
+	int usable_leb_size = ubi->leb_size - data_pad;
+
+	if (copy_flag != 0 && copy_flag != 1) {
+		dbg_err("bad copy_flag");
+		goto bad;
+	}
+
+	if (vol_id < 0 || lnum < 0 || data_size < 0 || used_ebs < 0 ||
+	    data_pad < 0) {
+		dbg_err("negative values");
+		goto bad;
+	}
+
+	if (vol_id >= UBI_MAX_VOLUMES && vol_id < UBI_INTERNAL_VOL_START) {
+		dbg_err("bad vol_id");
+		goto bad;
+	}
+
+	if (vol_id < UBI_INTERNAL_VOL_START && compat != 0) {
+		dbg_err("bad compat");
+		goto bad;
+	}
+
+	if (vol_id >= UBI_INTERNAL_VOL_START && compat != UBI_COMPAT_DELETE &&
+	    compat != UBI_COMPAT_RO && compat != UBI_COMPAT_PRESERVE &&
+	    compat != UBI_COMPAT_REJECT) {
+		dbg_err("bad compat");
+		goto bad;
+	}
+
+	if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
+		dbg_err("bad vol_type");
+		goto bad;
+	}
+
+	if (data_pad >= ubi->leb_size / 2) {
+		dbg_err("bad data_pad");
+		goto bad;
+	}
+
+	if (vol_type == UBI_VID_STATIC) {
+		/*
+		 * Although from high-level point of view static volumes may
+		 * contain zero bytes of data, but no VID headers can contain
+		 * zero at these fields, because they empty volumes do not have
+		 * mapped logical eraseblocks.
+		 */
+		if (used_ebs == 0) {
+			dbg_err("zero used_ebs");
+			goto bad;
+		}
+		if (data_size == 0) {
+			dbg_err("zero data_size");
+			goto bad;
+		}
+		if (lnum < used_ebs - 1) {
+			if (data_size != usable_leb_size) {
+				dbg_err("bad data_size");
+				goto bad;
+			}
+		} else if (lnum == used_ebs - 1) {
+			if (data_size == 0) {
+				dbg_err("bad data_size at last LEB");
+				goto bad;
+			}
+		} else {
+			dbg_err("too high lnum");
+			goto bad;
+		}
+	} else {
+		if (copy_flag == 0) {
+			if (data_crc != 0) {
+				dbg_err("non-zero data CRC");
+				goto bad;
+			}
+			if (data_size != 0) {
+				dbg_err("non-zero data_size");
+				goto bad;
+			}
+		} else {
+			if (data_size == 0) {
+				dbg_err("zero data_size of copy");
+				goto bad;
+			}
+		}
+		if (used_ebs != 0) {
+			dbg_err("bad used_ebs");
+			goto bad;
+		}
+	}
+
+	return 0;
+
+bad:
+	ubi_err("bad VID header");
+	ubi_dbg_dump_vid_hdr(vid_hdr);
+	ubi_dbg_dump_stack();
+	return 1;
+}
+
+/**
+ * ubi_io_read_vid_hdr - read and check a volume identifier header.
+ * @ubi: UBI device description object
+ * @pnum: physical eraseblock number to read from
+ * @vid_hdr: &struct ubi_vid_hdr object where to store the read volume
+ * identifier header
+ * @verbose: be verbose if the header is corrupted or wasn't found
+ *
+ * This function reads the volume identifier header from physical eraseblock
+ * @pnum and stores it in @vid_hdr. It also checks CRC checksum of the read
+ * volume identifier header. The following codes may be returned:
+ *
+ * o %0 if the CRC checksum is correct and the header was successfully read;
+ * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
+ *   and corrected by the flash driver; this is harmless but may indicate that
+ *   this eraseblock may become bad soon;
+ * o %UBI_IO_BAD_VID_HRD if the volume identifier header is corrupted (a CRC
+ *   error detected);
+ * o %UBI_IO_PEB_FREE if the physical eraseblock is free (i.e., there is no VID
+ *   header there);
+ * o a negative error code in case of failure.
+ */
+int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
+			struct ubi_vid_hdr *vid_hdr, int verbose)
+{
+	int err, read_err = 0;
+	uint32_t crc, magic, hdr_crc;
+	void *p;
+
+	dbg_io("read VID header from PEB %d", pnum);
+	ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
+	if (UBI_IO_DEBUG)
+		verbose = 1;
+
+	p = (char *)vid_hdr - ubi->vid_hdr_shift;
+	err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
+			  ubi->vid_hdr_alsize);
+	if (err) {
+		if (err != UBI_IO_BITFLIPS && err != -EBADMSG)
+			return err;
+
+		/*
+		 * We read all the data, but either a correctable bit-flip
+		 * occurred, or MTD reported about some data integrity error,
+		 * like an ECC error in case of NAND. The former is harmless,
+		 * the later may mean the read data is corrupted. But we have a
+		 * CRC check-sum and we will identify this. If the VID header is
+		 * still OK, we just report this as there was a bit-flip.
+		 */
+		read_err = err;
+	}
+
+	magic = be32_to_cpu(vid_hdr->magic);
+	if (magic != UBI_VID_HDR_MAGIC) {
+		/*
+		 * If we have read all 0xFF bytes, the VID header probably does
+		 * not exist and the physical eraseblock is assumed to be free.
+		 *
+		 * But if there was a read error, we do not test the data for
+		 * 0xFFs. Even if it does contain all 0xFFs, this error
+		 * indicates that something is still wrong with this physical
+		 * eraseblock and it cannot be regarded as free.
+		 */
+		if (read_err != -EBADMSG &&
+		    check_pattern(vid_hdr, 0xFF, UBI_VID_HDR_SIZE)) {
+			/* The physical eraseblock is supposedly free */
+
+			/*
+			 * The below is just a paranoid check, it has to be
+			 * compiled out if paranoid checks are disabled.
+			 */
+			err = paranoid_check_all_ff(ubi, pnum, ubi->leb_start,
+						    ubi->leb_size);
+			if (err)
+				return err > 0 ? UBI_IO_BAD_VID_HDR : err;
+
+			if (verbose)
+				ubi_warn("no VID header found at PEB %d, "
+					 "only 0xFF bytes", pnum);
+			return UBI_IO_PEB_FREE;
+		}
+
+		/*
+		 * This is not a valid VID header, and these are not 0xFF
+		 * bytes. Report that the header is corrupted.
+		 */
+		if (verbose) {
+			ubi_warn("bad magic number at PEB %d: %08x instead of "
+				 "%08x", pnum, magic, UBI_VID_HDR_MAGIC);
+			ubi_dbg_dump_vid_hdr(vid_hdr);
+		}
+		return UBI_IO_BAD_VID_HDR;
+	}
+
+	crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
+	hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
+
+	if (hdr_crc != crc) {
+		if (verbose) {
+			ubi_warn("bad CRC at PEB %d, calculated %#08x, "
+				 "read %#08x", pnum, crc, hdr_crc);
+			ubi_dbg_dump_vid_hdr(vid_hdr);
+		}
+		return UBI_IO_BAD_VID_HDR;
+	}
+
+	/* Validate the VID header that we have just read */
+	err = validate_vid_hdr(ubi, vid_hdr);
+	if (err) {
+		ubi_err("validation failed for PEB %d", pnum);
+		return -EINVAL;
+	}
+
+	return read_err ? UBI_IO_BITFLIPS : 0;
+}
+
+/**
+ * ubi_io_write_vid_hdr - write a volume identifier header.
+ * @ubi: UBI device description object
+ * @pnum: the physical eraseblock number to write to
+ * @vid_hdr: the volume identifier header to write
+ *
+ * This function writes the volume identifier header described by @vid_hdr to
+ * physical eraseblock @pnum. This function automatically fills the
+ * @vid_hdr->magic and the @vid_hdr->version fields, as well as calculates
+ * header CRC checksum and stores it at vid_hdr->hdr_crc.
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure. If %-EIO is returned, the physical eraseblock probably went
+ * bad.
+ */
+int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
+			 struct ubi_vid_hdr *vid_hdr)
+{
+	int err;
+	uint32_t crc;
+	void *p;
+
+	dbg_io("write VID header to PEB %d", pnum);
+	ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
+
+	err = paranoid_check_peb_ec_hdr(ubi, pnum);
+	if (err)
+		return err > 0 ? -EINVAL: err;
+
+	vid_hdr->magic = cpu_to_be32(UBI_VID_HDR_MAGIC);
+	vid_hdr->version = UBI_VERSION;
+	crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
+	vid_hdr->hdr_crc = cpu_to_be32(crc);
+
+	err = paranoid_check_vid_hdr(ubi, pnum, vid_hdr);
+	if (err)
+		return -EINVAL;
+
+	p = (char *)vid_hdr - ubi->vid_hdr_shift;
+	err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
+			   ubi->vid_hdr_alsize);
+	return err;
+}
+
+#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
+
+/**
+ * paranoid_check_not_bad - ensure that a physical eraseblock is not bad.
+ * @ubi: UBI device description object
+ * @pnum: physical eraseblock number to check
+ *
+ * This function returns zero if the physical eraseblock is good, a positive
+ * number if it is bad and a negative error code if an error occurred.
+ */
+static int paranoid_check_not_bad(const struct ubi_device *ubi, int pnum)
+{
+	int err;
+
+	err = ubi_io_is_bad(ubi, pnum);
+	if (!err)
+		return err;
+
+	ubi_err("paranoid check failed for PEB %d", pnum);
+	ubi_dbg_dump_stack();
+	return err;
+}
+
+/**
+ * paranoid_check_ec_hdr - check if an erase counter header is all right.
+ * @ubi: UBI device description object
+ * @pnum: physical eraseblock number the erase counter header belongs to
+ * @ec_hdr: the erase counter header to check
+ *
+ * This function returns zero if the erase counter header contains valid
+ * values, and %1 if not.
+ */
+static int paranoid_check_ec_hdr(const struct ubi_device *ubi, int pnum,
+				 const struct ubi_ec_hdr *ec_hdr)
+{
+	int err;
+	uint32_t magic;
+
+	magic = be32_to_cpu(ec_hdr->magic);
+	if (magic != UBI_EC_HDR_MAGIC) {
+		ubi_err("bad magic %#08x, must be %#08x",
+			magic, UBI_EC_HDR_MAGIC);
+		goto fail;
+	}
+
+	err = validate_ec_hdr(ubi, ec_hdr);
+	if (err) {
+		ubi_err("paranoid check failed for PEB %d", pnum);
+		goto fail;
+	}
+
+	return 0;
+
+fail:
+	ubi_dbg_dump_ec_hdr(ec_hdr);
+	ubi_dbg_dump_stack();
+	return 1;
+}
+
+/**
+ * paranoid_check_peb_ec_hdr - check that the erase counter header of a
+ * physical eraseblock is in-place and is all right.
+ * @ubi: UBI device description object
+ * @pnum: the physical eraseblock number to check
+ *
+ * This function returns zero if the erase counter header is all right, %1 if
+ * not, and a negative error code if an error occurred.
+ */
+static int paranoid_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum)
+{
+	int err;
+	uint32_t crc, hdr_crc;
+	struct ubi_ec_hdr *ec_hdr;
+
+	ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
+	if (!ec_hdr)
+		return -ENOMEM;
+
+	err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
+	if (err && err != UBI_IO_BITFLIPS && err != -EBADMSG)
+		goto exit;
+
+	crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
+	hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
+	if (hdr_crc != crc) {
+		ubi_err("bad CRC, calculated %#08x, read %#08x", crc, hdr_crc);
+		ubi_err("paranoid check failed for PEB %d", pnum);
+		ubi_dbg_dump_ec_hdr(ec_hdr);
+		ubi_dbg_dump_stack();
+		err = 1;
+		goto exit;
+	}
+
+	err = paranoid_check_ec_hdr(ubi, pnum, ec_hdr);
+
+exit:
+	kfree(ec_hdr);
+	return err;
+}
+
+/**
+ * paranoid_check_vid_hdr - check that a volume identifier header is all right.
+ * @ubi: UBI device description object
+ * @pnum: physical eraseblock number the volume identifier header belongs to
+ * @vid_hdr: the volume identifier header to check
+ *
+ * This function returns zero if the volume identifier header is all right, and
+ * %1 if not.
+ */
+static int paranoid_check_vid_hdr(const struct ubi_device *ubi, int pnum,
+				  const struct ubi_vid_hdr *vid_hdr)
+{
+	int err;
+	uint32_t magic;
+
+	magic = be32_to_cpu(vid_hdr->magic);
+	if (magic != UBI_VID_HDR_MAGIC) {
+		ubi_err("bad VID header magic %#08x at PEB %d, must be %#08x",
+			magic, pnum, UBI_VID_HDR_MAGIC);
+		goto fail;
+	}
+
+	err = validate_vid_hdr(ubi, vid_hdr);
+	if (err) {
+		ubi_err("paranoid check failed for PEB %d", pnum);
+		goto fail;
+	}
+
+	return err;
+
+fail:
+	ubi_err("paranoid check failed for PEB %d", pnum);
+	ubi_dbg_dump_vid_hdr(vid_hdr);
+	ubi_dbg_dump_stack();
+	return 1;
+
+}
+
+/**
+ * paranoid_check_peb_vid_hdr - check that the volume identifier header of a
+ * physical eraseblock is in-place and is all right.
+ * @ubi: UBI device description object
+ * @pnum: the physical eraseblock number to check
+ *
+ * This function returns zero if the volume identifier header is all right,
+ * %1 if not, and a negative error code if an error occurred.
+ */
+static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
+{
+	int err;
+	uint32_t crc, hdr_crc;
+	struct ubi_vid_hdr *vid_hdr;
+	void *p;
+
+	vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
+	if (!vid_hdr)
+		return -ENOMEM;
+
+	p = (char *)vid_hdr - ubi->vid_hdr_shift;
+	err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
+			  ubi->vid_hdr_alsize);
+	if (err && err != UBI_IO_BITFLIPS && err != -EBADMSG)
+		goto exit;
+
+	crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_EC_HDR_SIZE_CRC);
+	hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
+	if (hdr_crc != crc) {
+		ubi_err("bad VID header CRC at PEB %d, calculated %#08x, "
+			"read %#08x", pnum, crc, hdr_crc);
+		ubi_err("paranoid check failed for PEB %d", pnum);
+		ubi_dbg_dump_vid_hdr(vid_hdr);
+		ubi_dbg_dump_stack();
+		err = 1;
+		goto exit;
+	}
+
+	err = paranoid_check_vid_hdr(ubi, pnum, vid_hdr);
+
+exit:
+	ubi_free_vid_hdr(ubi, vid_hdr);
+	return err;
+}
+
+/**
+ * paranoid_check_all_ff - check that a region of flash is empty.
+ * @ubi: UBI device description object
+ * @pnum: the physical eraseblock number to check
+ * @offset: the starting offset within the physical eraseblock to check
+ * @len: the length of the region to check
+ *
+ * This function returns zero if only 0xFF bytes are present at offset
+ * @offset of the physical eraseblock @pnum, %1 if not, and a negative error
+ * code if an error occurred.
+ */
+static int paranoid_check_all_ff(struct ubi_device *ubi, int pnum, int offset,
+				 int len)
+{
+	size_t read;
+	int err;
+	loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
+
+	mutex_lock(&ubi->dbg_buf_mutex);
+	err = ubi->mtd->read(ubi->mtd, addr, len, &read, ubi->dbg_peb_buf);
+	if (err && err != -EUCLEAN) {
+		ubi_err("error %d while reading %d bytes from PEB %d:%d, "
+			"read %zd bytes", err, len, pnum, offset, read);
+		goto error;
+	}
+
+	err = check_pattern(ubi->dbg_peb_buf, 0xFF, len);
+	if (err == 0) {
+		ubi_err("flash region at PEB %d:%d, length %d does not "
+			"contain all 0xFF bytes", pnum, offset, len);
+		goto fail;
+	}
+	mutex_unlock(&ubi->dbg_buf_mutex);
+
+	return 0;
+
+fail:
+	ubi_err("paranoid check failed for PEB %d", pnum);
+	dbg_msg("hex dump of the %d-%d region", offset, offset + len);
+	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
+		       ubi->dbg_peb_buf, len, 1);
+	err = 1;
+error:
+	ubi_dbg_dump_stack();
+	mutex_unlock(&ubi->dbg_buf_mutex);
+	return err;
+}
+
+#endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */
diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c
new file mode 100644
index 0000000..423d479
--- /dev/null
+++ b/drivers/mtd/ubi/kapi.c
@@ -0,0 +1,638 @@
+/*
+ * 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)
+ */
+
+/* This file mostly implements UBI kernel API functions */
+
+#ifdef UBI_LINUX
+#include <linux/module.h>
+#include <linux/err.h>
+#include <asm/div64.h>
+#endif
+
+#include <ubi_uboot.h>
+#include "ubi.h"
+
+/**
+ * ubi_get_device_info - get information about UBI device.
+ * @ubi_num: UBI device number
+ * @di: the information is stored here
+ *
+ * This function returns %0 in case of success, %-EINVAL if the UBI device
+ * number is invalid, and %-ENODEV if there is no such UBI device.
+ */
+int ubi_get_device_info(int ubi_num, struct ubi_device_info *di)
+{
+	struct ubi_device *ubi;
+
+	if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
+		return -EINVAL;
+
+	ubi = ubi_get_device(ubi_num);
+	if (!ubi)
+		return -ENODEV;
+
+	di->ubi_num = ubi->ubi_num;
+	di->leb_size = ubi->leb_size;
+	di->min_io_size = ubi->min_io_size;
+	di->ro_mode = ubi->ro_mode;
+	di->cdev = ubi->cdev.dev;
+
+	ubi_put_device(ubi);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ubi_get_device_info);
+
+/**
+ * ubi_get_volume_info - get information about UBI volume.
+ * @desc: volume descriptor
+ * @vi: the information is stored here
+ */
+void ubi_get_volume_info(struct ubi_volume_desc *desc,
+			 struct ubi_volume_info *vi)
+{
+	const struct ubi_volume *vol = desc->vol;
+	const struct ubi_device *ubi = vol->ubi;
+
+	vi->vol_id = vol->vol_id;
+	vi->ubi_num = ubi->ubi_num;
+	vi->size = vol->reserved_pebs;
+	vi->used_bytes = vol->used_bytes;
+	vi->vol_type = vol->vol_type;
+	vi->corrupted = vol->corrupted;
+	vi->upd_marker = vol->upd_marker;
+	vi->alignment = vol->alignment;
+	vi->usable_leb_size = vol->usable_leb_size;
+	vi->name_len = vol->name_len;
+	vi->name = vol->name;
+	vi->cdev = vol->cdev.dev;
+}
+EXPORT_SYMBOL_GPL(ubi_get_volume_info);
+
+/**
+ * ubi_open_volume - open UBI volume.
+ * @ubi_num: UBI device number
+ * @vol_id: volume ID
+ * @mode: open mode
+ *
+ * The @mode parameter specifies if the volume should be opened in read-only
+ * mode, read-write mode, or exclusive mode. The exclusive mode guarantees that
+ * nobody else will be able to open this volume. UBI allows to have many volume
+ * readers and one writer at a time.
+ *
+ * If a static volume is being opened for the first time since boot, it will be
+ * checked by this function, which means it will be fully read and the CRC
+ * checksum of each logical eraseblock will be checked.
+ *
+ * This function returns volume descriptor in case of success and a negative
+ * error code in case of failure.
+ */
+struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
+{
+	int err;
+	struct ubi_volume_desc *desc;
+	struct ubi_device *ubi;
+	struct ubi_volume *vol;
+
+	dbg_msg("open device %d volume %d, mode %d", ubi_num, vol_id, mode);
+
+	if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
+		return ERR_PTR(-EINVAL);
+
+	if (mode != UBI_READONLY && mode != UBI_READWRITE &&
+	    mode != UBI_EXCLUSIVE)
+		return ERR_PTR(-EINVAL);
+
+	/*
+	 * First of all, we have to get the UBI device to prevent its removal.
+	 */
+	ubi = ubi_get_device(ubi_num);
+	if (!ubi)
+		return ERR_PTR(-ENODEV);
+
+	if (vol_id < 0 || vol_id >= ubi->vtbl_slots) {
+		err = -EINVAL;
+		goto out_put_ubi;
+	}
+
+	desc = kmalloc(sizeof(struct ubi_volume_desc), GFP_KERNEL);
+	if (!desc) {
+		err = -ENOMEM;
+		goto out_put_ubi;
+	}
+
+	err = -ENODEV;
+	if (!try_module_get(THIS_MODULE))
+		goto out_free;
+
+	spin_lock(&ubi->volumes_lock);
+	vol = ubi->volumes[vol_id];
+	if (!vol)
+		goto out_unlock;
+
+	err = -EBUSY;
+	switch (mode) {
+	case UBI_READONLY:
+		if (vol->exclusive)
+			goto out_unlock;
+		vol->readers += 1;
+		break;
+
+	case UBI_READWRITE:
+		if (vol->exclusive || vol->writers > 0)
+			goto out_unlock;
+		vol->writers += 1;
+		break;
+
+	case UBI_EXCLUSIVE:
+		if (vol->exclusive || vol->writers || vol->readers)
+			goto out_unlock;
+		vol->exclusive = 1;
+		break;
+	}
+	get_device(&vol->dev);
+	vol->ref_count += 1;
+	spin_unlock(&ubi->volumes_lock);
+
+	desc->vol = vol;
+	desc->mode = mode;
+
+	mutex_lock(&ubi->ckvol_mutex);
+	if (!vol->checked) {
+		/* This is the first open - check the volume */
+		err = ubi_check_volume(ubi, vol_id);
+		if (err < 0) {
+			mutex_unlock(&ubi->ckvol_mutex);
+			ubi_close_volume(desc);
+			return ERR_PTR(err);
+		}
+		if (err == 1) {
+			ubi_warn("volume %d on UBI device %d is corrupted",
+				 vol_id, ubi->ubi_num);
+			vol->corrupted = 1;
+		}
+		vol->checked = 1;
+	}
+	mutex_unlock(&ubi->ckvol_mutex);
+
+	return desc;
+
+out_unlock:
+	spin_unlock(&ubi->volumes_lock);
+	module_put(THIS_MODULE);
+out_free:
+	kfree(desc);
+out_put_ubi:
+	ubi_put_device(ubi);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(ubi_open_volume);
+
+/**
+ * ubi_open_volume_nm - open UBI volume by name.
+ * @ubi_num: UBI device number
+ * @name: volume name
+ * @mode: open mode
+ *
+ * This function is similar to 'ubi_open_volume()', but opens a volume by name.
+ */
+struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
+					   int mode)
+{
+	int i, vol_id = -1, len;
+	struct ubi_device *ubi;
+	struct ubi_volume_desc *ret;
+
+	dbg_msg("open volume %s, mode %d", name, mode);
+
+	if (!name)
+		return ERR_PTR(-EINVAL);
+
+	len = strnlen(name, UBI_VOL_NAME_MAX + 1);
+	if (len > UBI_VOL_NAME_MAX)
+		return ERR_PTR(-EINVAL);
+
+	if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
+		return ERR_PTR(-EINVAL);
+
+	ubi = ubi_get_device(ubi_num);
+	if (!ubi)
+		return ERR_PTR(-ENODEV);
+
+	spin_lock(&ubi->volumes_lock);
+	/* Walk all volumes of this UBI device */
+	for (i = 0; i < ubi->vtbl_slots; i++) {
+		struct ubi_volume *vol = ubi->volumes[i];
+
+		if (vol && len == vol->name_len && !strcmp(name, vol->name)) {
+			vol_id = i;
+			break;
+		}
+	}
+	spin_unlock(&ubi->volumes_lock);
+
+	if (vol_id >= 0)
+		ret = ubi_open_volume(ubi_num, vol_id, mode);
+	else
+		ret = ERR_PTR(-ENODEV);
+
+	/*
+	 * We should put the UBI device even in case of success, because
+	 * 'ubi_open_volume()' took a reference as well.
+	 */
+	ubi_put_device(ubi);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
+
+/**
+ * ubi_close_volume - close UBI volume.
+ * @desc: volume descriptor
+ */
+void ubi_close_volume(struct ubi_volume_desc *desc)
+{
+	struct ubi_volume *vol = desc->vol;
+	struct ubi_device *ubi = vol->ubi;
+
+	dbg_msg("close volume %d, mode %d", vol->vol_id, desc->mode);
+
+	spin_lock(&ubi->volumes_lock);
+	switch (desc->mode) {
+	case UBI_READONLY:
+		vol->readers -= 1;
+		break;
+	case UBI_READWRITE:
+		vol->writers -= 1;
+		break;
+	case UBI_EXCLUSIVE:
+		vol->exclusive = 0;
+	}
+	vol->ref_count -= 1;
+	spin_unlock(&ubi->volumes_lock);
+
+	kfree(desc);
+	put_device(&vol->dev);
+	ubi_put_device(ubi);
+	module_put(THIS_MODULE);
+}
+EXPORT_SYMBOL_GPL(ubi_close_volume);
+
+/**
+ * ubi_leb_read - read data.
+ * @desc: volume descriptor
+ * @lnum: logical eraseblock number to read from
+ * @buf: buffer where to store the read data
+ * @offset: offset within the logical eraseblock to read from
+ * @len: how many bytes to read
+ * @check: whether UBI has to check the read data's CRC or not.
+ *
+ * This function reads data from offset @offset of logical eraseblock @lnum and
+ * stores the data at @buf. When reading from static volumes, @check specifies
+ * whether the data has to be checked or not. If yes, the whole logical
+ * eraseblock will be read and its CRC checksum will be checked (i.e., the CRC
+ * checksum is per-eraseblock). So checking may substantially slow down the
+ * read speed. The @check argument is ignored for dynamic volumes.
+ *
+ * In case of success, this function returns zero. In case of failure, this
+ * function returns a negative error code.
+ *
+ * %-EBADMSG error code is returned:
+ * o for both static and dynamic volumes if MTD driver has detected a data
+ *   integrity problem (unrecoverable ECC checksum mismatch in case of NAND);
+ * o for static volumes in case of data CRC mismatch.
+ *
+ * If the volume is damaged because of an interrupted update this function just
+ * returns immediately with %-EBADF error code.
+ */
+int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
+		 int len, int check)
+{
+	struct ubi_volume *vol = desc->vol;
+	struct ubi_device *ubi = vol->ubi;
+	int err, vol_id = vol->vol_id;
+
+	dbg_msg("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
+
+	if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 ||
+	    lnum >= vol->used_ebs || offset < 0 || len < 0 ||
+	    offset + len > vol->usable_leb_size)
+		return -EINVAL;
+
+	if (vol->vol_type == UBI_STATIC_VOLUME) {
+		if (vol->used_ebs == 0)
+			/* Empty static UBI volume */
+			return 0;
+		if (lnum == vol->used_ebs - 1 &&
+		    offset + len > vol->last_eb_bytes)
+			return -EINVAL;
+	}
+
+	if (vol->upd_marker)
+		return -EBADF;
+	if (len == 0)
+		return 0;
+
+	err = ubi_eba_read_leb(ubi, vol, lnum, buf, offset, len, check);
+	if (err && err == -EBADMSG && vol->vol_type == UBI_STATIC_VOLUME) {
+		ubi_warn("mark volume %d as corrupted", vol_id);
+		vol->corrupted = 1;
+	}
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(ubi_leb_read);
+
+/**
+ * ubi_leb_write - write data.
+ * @desc: volume descriptor
+ * @lnum: logical eraseblock number to write to
+ * @buf: data to write
+ * @offset: offset within the logical eraseblock where to write
+ * @len: how many bytes to write
+ * @dtype: expected data type
+ *
+ * This function writes @len bytes of data from @buf to offset @offset of
+ * logical eraseblock @lnum. The @dtype argument describes expected lifetime of
+ * the data.
+ *
+ * This function takes care of physical eraseblock write failures. If write to
+ * the physical eraseblock write operation fails, the logical eraseblock is
+ * re-mapped to another physical eraseblock, the data is recovered, and the
+ * write finishes. UBI has a pool of reserved physical eraseblocks for this.
+ *
+ * If all the data were successfully written, zero is returned. If an error
+ * occurred and UBI has not been able to recover from it, this function returns
+ * a negative error code. Note, in case of an error, it is possible that
+ * something was still written to the flash media, but that may be some
+ * garbage.
+ *
+ * If the volume is damaged because of an interrupted update this function just
+ * returns immediately with %-EBADF code.
+ */
+int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
+		  int offset, int len, int dtype)
+{
+	struct ubi_volume *vol = desc->vol;
+	struct ubi_device *ubi = vol->ubi;
+	int vol_id = vol->vol_id;
+
+	dbg_msg("write %d bytes to LEB %d:%d:%d", len, vol_id, lnum, offset);
+
+	if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
+		return -EINVAL;
+
+	if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
+		return -EROFS;
+
+	if (lnum < 0 || lnum >= vol->reserved_pebs || offset < 0 || len < 0 ||
+	    offset + len > vol->usable_leb_size ||
+	    offset & (ubi->min_io_size - 1) || len & (ubi->min_io_size - 1))
+		return -EINVAL;
+
+	if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM &&
+	    dtype != UBI_UNKNOWN)
+		return -EINVAL;
+
+	if (vol->upd_marker)
+		return -EBADF;
+
+	if (len == 0)
+		return 0;
+
+	return ubi_eba_write_leb(ubi, vol, lnum, buf, offset, len, dtype);
+}
+EXPORT_SYMBOL_GPL(ubi_leb_write);
+
+/*
+ * ubi_leb_change - change logical eraseblock atomically.
+ * @desc: volume descriptor
+ * @lnum: logical eraseblock number to change
+ * @buf: data to write
+ * @len: how many bytes to write
+ * @dtype: expected data type
+ *
+ * This function changes the contents of a logical eraseblock atomically. @buf
+ * has to contain new logical eraseblock data, and @len - the length of the
+ * data, which has to be aligned. The length may be shorter then the logical
+ * eraseblock size, ant the logical eraseblock may be appended to more times
+ * later on. This function guarantees that in case of an unclean reboot the old
+ * contents is preserved. Returns zero in case of success and a negative error
+ * code in case of failure.
+ */
+int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
+		   int len, int dtype)
+{
+	struct ubi_volume *vol = desc->vol;
+	struct ubi_device *ubi = vol->ubi;
+	int vol_id = vol->vol_id;
+
+	dbg_msg("atomically write %d bytes to LEB %d:%d", len, vol_id, lnum);
+
+	if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
+		return -EINVAL;
+
+	if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
+		return -EROFS;
+
+	if (lnum < 0 || lnum >= vol->reserved_pebs || len < 0 ||
+	    len > vol->usable_leb_size || len & (ubi->min_io_size - 1))
+		return -EINVAL;
+
+	if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM &&
+	    dtype != UBI_UNKNOWN)
+		return -EINVAL;
+
+	if (vol->upd_marker)
+		return -EBADF;
+
+	if (len == 0)
+		return 0;
+
+	return ubi_eba_atomic_leb_change(ubi, vol, lnum, buf, len, dtype);
+}
+EXPORT_SYMBOL_GPL(ubi_leb_change);
+
+/**
+ * ubi_leb_erase - erase logical eraseblock.
+ * @desc: volume descriptor
+ * @lnum: logical eraseblock number
+ *
+ * This function un-maps logical eraseblock @lnum and synchronously erases the
+ * correspondent physical eraseblock. Returns zero in case of success and a
+ * negative error code in case of failure.
+ *
+ * If the volume is damaged because of an interrupted update this function just
+ * returns immediately with %-EBADF code.
+ */
+int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum)
+{
+	struct ubi_volume *vol = desc->vol;
+	struct ubi_device *ubi = vol->ubi;
+	int err;
+
+	dbg_msg("erase LEB %d:%d", vol->vol_id, lnum);
+
+	if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
+		return -EROFS;
+
+	if (lnum < 0 || lnum >= vol->reserved_pebs)
+		return -EINVAL;
+
+	if (vol->upd_marker)
+		return -EBADF;
+
+	err = ubi_eba_unmap_leb(ubi, vol, lnum);
+	if (err)
+		return err;
+
+	return ubi_wl_flush(ubi);
+}
+EXPORT_SYMBOL_GPL(ubi_leb_erase);
+
+/**
+ * ubi_leb_unmap - un-map logical eraseblock.
+ * @desc: volume descriptor
+ * @lnum: logical eraseblock number
+ *
+ * This function un-maps logical eraseblock @lnum and schedules the
+ * corresponding physical eraseblock for erasure, so that it will eventually be
+ * physically erased in background. This operation is much faster then the
+ * erase operation.
+ *
+ * Unlike erase, the un-map operation does not guarantee that the logical
+ * eraseblock will contain all 0xFF bytes when UBI is initialized again. For
+ * example, if several logical eraseblocks are un-mapped, and an unclean reboot
+ * happens after this, the logical eraseblocks will not necessarily be
+ * un-mapped again when this MTD device is attached. They may actually be
+ * mapped to the same physical eraseblocks again. So, this function has to be
+ * used with care.
+ *
+ * In other words, when un-mapping a logical eraseblock, UBI does not store
+ * any information about this on the flash media, it just marks the logical
+ * eraseblock as "un-mapped" in RAM. If UBI is detached before the physical
+ * eraseblock is physically erased, it will be mapped again to the same logical
+ * eraseblock when the MTD device is attached again.
+ *
+ * The main and obvious use-case of this function is when the contents of a
+ * logical eraseblock has to be re-written. Then it is much more efficient to
+ * first un-map it, then write new data, rather then first erase it, then write
+ * new data. Note, once new data has been written to the logical eraseblock,
+ * UBI guarantees that the old contents has gone forever. In other words, if an
+ * unclean reboot happens after the logical eraseblock has been un-mapped and
+ * then written to, it will contain the last written data.
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure. If the volume is damaged because of an interrupted update
+ * this function just returns immediately with %-EBADF code.
+ */
+int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum)
+{
+	struct ubi_volume *vol = desc->vol;
+	struct ubi_device *ubi = vol->ubi;
+
+	dbg_msg("unmap LEB %d:%d", vol->vol_id, lnum);
+
+	if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
+		return -EROFS;
+
+	if (lnum < 0 || lnum >= vol->reserved_pebs)
+		return -EINVAL;
+
+	if (vol->upd_marker)
+		return -EBADF;
+
+	return ubi_eba_unmap_leb(ubi, vol, lnum);
+}
+EXPORT_SYMBOL_GPL(ubi_leb_unmap);
+
+/**
+ * ubi_leb_map - map logical erasblock to a physical eraseblock.
+ * @desc: volume descriptor
+ * @lnum: logical eraseblock number
+ * @dtype: expected data type
+ *
+ * This function maps an un-mapped logical eraseblock @lnum to a physical
+ * eraseblock. This means, that after a successfull invocation of this
+ * function the logical eraseblock @lnum will be empty (contain only %0xFF
+ * bytes) and be mapped to a physical eraseblock, even if an unclean reboot
+ * happens.
+ *
+ * This function returns zero in case of success, %-EBADF if the volume is
+ * damaged because of an interrupted update, %-EBADMSG if the logical
+ * eraseblock is already mapped, and other negative error codes in case of
+ * other failures.
+ */
+int ubi_leb_map(struct ubi_volume_desc *desc, int lnum, int dtype)
+{
+	struct ubi_volume *vol = desc->vol;
+	struct ubi_device *ubi = vol->ubi;
+
+	dbg_msg("unmap LEB %d:%d", vol->vol_id, lnum);
+
+	if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
+		return -EROFS;
+
+	if (lnum < 0 || lnum >= vol->reserved_pebs)
+		return -EINVAL;
+
+	if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM &&
+	    dtype != UBI_UNKNOWN)
+		return -EINVAL;
+
+	if (vol->upd_marker)
+		return -EBADF;
+
+	if (vol->eba_tbl[lnum] >= 0)
+		return -EBADMSG;
+
+	return ubi_eba_write_leb(ubi, vol, lnum, NULL, 0, 0, dtype);
+}
+EXPORT_SYMBOL_GPL(ubi_leb_map);
+
+/**
+ * ubi_is_mapped - check if logical eraseblock is mapped.
+ * @desc: volume descriptor
+ * @lnum: logical eraseblock number
+ *
+ * This function checks if logical eraseblock @lnum is mapped to a physical
+ * eraseblock. If a logical eraseblock is un-mapped, this does not necessarily
+ * mean it will still be un-mapped after the UBI device is re-attached. The
+ * logical eraseblock may become mapped to the physical eraseblock it was last
+ * mapped to.
+ *
+ * This function returns %1 if the LEB is mapped, %0 if not, and a negative
+ * error code in case of failure. If the volume is damaged because of an
+ * interrupted update this function just returns immediately with %-EBADF error
+ * code.
+ */
+int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum)
+{
+	struct ubi_volume *vol = desc->vol;
+
+	dbg_msg("test LEB %d:%d", vol->vol_id, lnum);
+
+	if (lnum < 0 || lnum >= vol->reserved_pebs)
+		return -EINVAL;
+
+	if (vol->upd_marker)
+		return -EBADF;
+
+	return vol->eba_tbl[lnum] >= 0;
+}
+EXPORT_SYMBOL_GPL(ubi_is_mapped);
diff --git a/drivers/mtd/ubi/misc.c b/drivers/mtd/ubi/misc.c
new file mode 100644
index 0000000..a6410bf
--- /dev/null
+++ b/drivers/mtd/ubi/misc.c
@@ -0,0 +1,106 @@
+/*
+ * 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)
+ */
+
+/* Here we keep miscellaneous functions which are used all over the UBI code */
+
+#include <ubi_uboot.h>
+#include "ubi.h"
+
+/**
+ * calc_data_len - calculate how much real data is stored in a buffer.
+ * @ubi: UBI device description object
+ * @buf: a buffer with the contents of the physical eraseblock
+ * @length: the buffer length
+ *
+ * This function calculates how much "real data" is stored in @buf and returnes
+ * the length. Continuous 0xFF bytes at the end of the buffer are not
+ * considered as "real data".
+ */
+int ubi_calc_data_len(const struct ubi_device *ubi, const void *buf,
+		      int length)
+{
+	int i;
+
+	ubi_assert(!(length & (ubi->min_io_size - 1)));
+
+	for (i = length - 1; i >= 0; i--)
+		if (((const uint8_t *)buf)[i] != 0xFF)
+			break;
+
+	/* The resulting length must be aligned to the minimum flash I/O size */
+	length = ALIGN(i + 1, ubi->min_io_size);
+	return length;
+}
+
+/**
+ * ubi_check_volume - check the contents of a static volume.
+ * @ubi: UBI device description object
+ * @vol_id: ID of the volume to check
+ *
+ * This function checks if static volume @vol_id is corrupted by fully reading
+ * it and checking data CRC. This function returns %0 if the volume is not
+ * corrupted, %1 if it is corrupted and a negative error code in case of
+ * failure. Dynamic volumes are not checked and zero is returned immediately.
+ */
+int ubi_check_volume(struct ubi_device *ubi, int vol_id)
+{
+	void *buf;
+	int err = 0, i;
+	struct ubi_volume *vol = ubi->volumes[vol_id];
+
+	if (vol->vol_type != UBI_STATIC_VOLUME)
+		return 0;
+
+	buf = vmalloc(vol->usable_leb_size);
+	if (!buf)
+		return -ENOMEM;
+
+	for (i = 0; i < vol->used_ebs; i++) {
+		int size;
+
+		if (i == vol->used_ebs - 1)
+			size = vol->last_eb_bytes;
+		else
+			size = vol->usable_leb_size;
+
+		err = ubi_eba_read_leb(ubi, vol, i, buf, 0, size, 1);
+		if (err) {
+			if (err == -EBADMSG)
+				err = 1;
+			break;
+		}
+	}
+
+	vfree(buf);
+	return err;
+}
+
+/**
+ * ubi_calculate_rsvd_pool - calculate how many PEBs must be reserved for bad
+ * eraseblock handling.
+ * @ubi: UBI device description object
+ */
+void ubi_calculate_reserved(struct ubi_device *ubi)
+{
+	ubi->beb_rsvd_level = ubi->good_peb_count/100;
+	ubi->beb_rsvd_level *= CONFIG_MTD_UBI_BEB_RESERVE;
+	if (ubi->beb_rsvd_level < MIN_RESEVED_PEBS)
+		ubi->beb_rsvd_level = MIN_RESEVED_PEBS;
+}