1 files changed, 433 insertions, 0 deletions

diff --git a/drivers/mtd/ubi/upd.c b/drivers/mtd/ubi/upd.c
new file mode 100644
index 000000000..39712560b
--- /dev/null
+++ b/drivers/mtd/ubi/upd.c
@@ -0,0 +1,433 @@
+/*
+ * Copyright (c) International Business Machines Corp., 2006
+ * Copyright (c) Nokia Corporation, 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)
+ *
+ * Jan 2007: Alexander Schmidt, hacked per-volume update.
+ */
+
+/*
+ * This file contains implementation of the volume update and atomic LEB change
+ * functionality.
+ *
+ * The update operation is based on the per-volume update marker which is
+ * stored in the volume table. The update marker is set before the update
+ * starts, and removed after the update has been finished. So if the update was
+ * interrupted by an unclean re-boot or due to some other reasons, the update
+ * marker stays on the flash media and UBI finds it when it attaches the MTD
+ * device next time. If the update marker is set for a volume, the volume is
+ * treated as damaged and most I/O operations are prohibited. Only a new update
+ * operation is allowed.
+ *
+ * Note, in general it is possible to implement the update operation as a
+ * transaction with a roll-back capability.
+ */
+
+#include <linux/err.h>
+#include <linux/uaccess.h>
+#include <linux/math64.h>
+#include "ubi.h"
+
+/**
+ * set_update_marker - set update marker.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ *
+ * This function sets the update marker flag for volume @vol. Returns zero
+ * in case of success and a negative error code in case of failure.
+ */
+static int set_update_marker(struct ubi_device *ubi, struct ubi_volume *vol)
+{
+	int err;
+	struct ubi_vtbl_record vtbl_rec;
+
+	dbg_gen("set update marker for volume %d", vol->vol_id);
+
+	if (vol->upd_marker) {
+		ubi_assert(ubi->vtbl[vol->vol_id].upd_marker);
+		dbg_gen("already set");
+		return 0;
+	}
+
+	vtbl_rec = ubi->vtbl[vol->vol_id];
+	vtbl_rec.upd_marker = 1;
+
+	mutex_lock(&ubi->device_mutex);
+	err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec);
+	vol->upd_marker = 1;
+	mutex_unlock(&ubi->device_mutex);
+	return err;
+}
+
+/**
+ * clear_update_marker - clear update marker.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ * @bytes: new data size in bytes
+ *
+ * This function clears the update marker for volume @vol, sets new volume
+ * data size and clears the "corrupted" flag (static volumes only). Returns
+ * zero in case of success and a negative error code in case of failure.
+ */
+static int clear_update_marker(struct ubi_device *ubi, struct ubi_volume *vol,
+			       long long bytes)
+{
+	int err;
+	struct ubi_vtbl_record vtbl_rec;
+
+	dbg_gen("clear update marker for volume %d", vol->vol_id);
+
+	vtbl_rec = ubi->vtbl[vol->vol_id];
+	ubi_assert(vol->upd_marker && vtbl_rec.upd_marker);
+	vtbl_rec.upd_marker = 0;
+
+	if (vol->vol_type == UBI_STATIC_VOLUME) {
+		vol->corrupted = 0;
+		vol->used_bytes = bytes;
+		vol->used_ebs = div_u64_rem(bytes, vol->usable_leb_size,
+					    &vol->last_eb_bytes);
+		if (vol->last_eb_bytes)
+			vol->used_ebs += 1;
+		else
+			vol->last_eb_bytes = vol->usable_leb_size;
+	}
+
+	mutex_lock(&ubi->device_mutex);
+	err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec);
+	vol->upd_marker = 0;
+	mutex_unlock(&ubi->device_mutex);
+	return err;
+}
+
+/**
+ * ubi_start_update - start volume update.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ * @bytes: update bytes
+ *
+ * This function starts volume update operation. If @bytes is zero, the volume
+ * is just wiped out. Returns zero in case of success and a negative error code
+ * in case of failure.
+ */
+int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol,
+		     long long bytes)
+{
+	int i, err;
+
+	dbg_gen("start update of volume %d, %llu bytes", vol->vol_id, bytes);
+	ubi_assert(!vol->updating && !vol->changing_leb);
+	vol->updating = 1;
+
+	vol->upd_buf = vmalloc(ubi->leb_size);
+	if (!vol->upd_buf)
+		return -ENOMEM;
+
+	err = set_update_marker(ubi, vol);
+	if (err)
+		return err;
+
+	/* Before updating - wipe out the volume */
+	for (i = 0; i < vol->reserved_pebs; i++) {
+		err = ubi_eba_unmap_leb(ubi, vol, i);
+		if (err)
+			return err;
+	}
+
+	err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL);
+	if (err)
+		return err;
+
+	if (bytes == 0) {
+		err = clear_update_marker(ubi, vol, 0);
+		if (err)
+			return err;
+
+		vfree(vol->upd_buf);
+		vol->updating = 0;
+		return 0;
+	}
+
+	vol->upd_ebs = div_u64(bytes + vol->usable_leb_size - 1,
+			       vol->usable_leb_size);
+	vol->upd_bytes = bytes;
+	vol->upd_received = 0;
+	return 0;
+}
+
+/**
+ * ubi_start_leb_change - start atomic LEB change.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ * @req: operation request
+ *
+ * This function starts atomic LEB change operation. Returns zero in case of
+ * success and a negative error code in case of failure.
+ */
+int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
+			 const struct ubi_leb_change_req *req)
+{
+	ubi_assert(!vol->updating && !vol->changing_leb);
+
+	dbg_gen("start changing LEB %d:%d, %u bytes",
+		vol->vol_id, req->lnum, req->bytes);
+	if (req->bytes == 0)
+		return ubi_eba_atomic_leb_change(ubi, vol, req->lnum, NULL, 0);
+
+	vol->upd_bytes = req->bytes;
+	vol->upd_received = 0;
+	vol->changing_leb = 1;
+	vol->ch_lnum = req->lnum;
+
+	vol->upd_buf = vmalloc(ALIGN((int)req->bytes, ubi->min_io_size));
+	if (!vol->upd_buf)
+		return -ENOMEM;
+
+	return 0;
+}
+
+/**
+ * write_leb - write update data.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ * @lnum: logical eraseblock number
+ * @buf: data to write
+ * @len: data size
+ * @used_ebs: how many logical eraseblocks will this volume contain (static
+ * volumes only)
+ *
+ * This function writes update data to corresponding logical eraseblock. In
+ * case of dynamic volume, this function checks if the data contains 0xFF bytes
+ * at the end. If yes, the 0xFF bytes are cut and not written. So if the whole
+ * buffer contains only 0xFF bytes, the LEB is left unmapped.
+ *
+ * The reason why we skip the trailing 0xFF bytes in case of dynamic volume is
+ * that we want to make sure that more data may be appended to the logical
+ * eraseblock in future. Indeed, writing 0xFF bytes may have side effects and
+ * this PEB won't be writable anymore. So if one writes the file-system image
+ * to the UBI volume where 0xFFs mean free space - UBI makes sure this free
+ * space is writable after the update.
+ *
+ * We do not do this for static volumes because they are read-only. But this
+ * also cannot be done because we have to store per-LEB CRC and the correct
+ * data length.
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure.
+ */
+static int write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
+		     void *buf, int len, int used_ebs)
+{
+	int err;
+
+	if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
+		int l = ALIGN(len, ubi->min_io_size);
+
+		memset(buf + len, 0xFF, l - len);
+		len = ubi_calc_data_len(ubi, buf, l);
+		if (len == 0) {
+			dbg_gen("all %d bytes contain 0xFF - skip", len);
+			return 0;
+		}
+
+		err = ubi_eba_write_leb(ubi, vol, lnum, buf, 0, len);
+	} else {
+		/*
+		 * When writing static volume, and this is the last logical
+		 * eraseblock, the length (@len) does not have to be aligned to
+		 * the minimal flash I/O unit. The 'ubi_eba_write_leb_st()'
+		 * function accepts exact (unaligned) length and stores it in
+		 * the VID header. And it takes care of proper alignment by
+		 * padding the buffer. Here we just make sure the padding will
+		 * contain zeros, not random trash.
+		 */
+		memset(buf + len, 0, vol->usable_leb_size - len);
+		err = ubi_eba_write_leb_st(ubi, vol, lnum, buf, len, used_ebs);
+	}
+
+	return err;
+}
+
+/**
+ * ubi_more_update_data - write more update data.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ * @buf: write data (user-space memory buffer)
+ * @count: how much bytes to write
+ *
+ * This function writes more data to the volume which is being updated. It may
+ * be called arbitrary number of times until all the update data arriveis. This
+ * function returns %0 in case of success, number of bytes written during the
+ * last call if the whole volume update has been successfully finished, and a
+ * negative error code in case of failure.
+ */
+int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol,
+			 const void __user *buf, int count)
+{
+	int lnum, offs, err = 0, len, to_write = count;
+
+	dbg_gen("write %d of %lld bytes, %lld already passed",
+		count, vol->upd_bytes, vol->upd_received);
+
+	if (ubi->ro_mode)
+		return -EROFS;
+
+	lnum = div_u64_rem(vol->upd_received,  vol->usable_leb_size, &offs);
+	if (vol->upd_received + count > vol->upd_bytes)
+		to_write = count = vol->upd_bytes - vol->upd_received;
+
+	/*
+	 * When updating volumes, we accumulate whole logical eraseblock of
+	 * data and write it at once.
+	 */
+	if (offs != 0) {
+		/*
+		 * This is a write to the middle of the logical eraseblock. We
+		 * copy the data to our update buffer and wait for more data or
+		 * flush it if the whole eraseblock is written or the update
+		 * is finished.
+		 */
+
+		len = vol->usable_leb_size - offs;
+		if (len > count)
+			len = count;
+
+		err = copy_from_user(vol->upd_buf + offs, buf, len);
+		if (err)
+			return -EFAULT;
+
+		if (offs + len == vol->usable_leb_size ||
+		    vol->upd_received + len == vol->upd_bytes) {
+			int flush_len = offs + len;
+
+			/*
+			 * OK, we gathered either the whole eraseblock or this
+			 * is the last chunk, it's time to flush the buffer.
+			 */
+			ubi_assert(flush_len <= vol->usable_leb_size);
+			err = write_leb(ubi, vol, lnum, vol->upd_buf, flush_len,
+					vol->upd_ebs);
+			if (err)
+				return err;
+		}
+
+		vol->upd_received += len;
+		count -= len;
+		buf += len;
+		lnum += 1;
+	}
+
+	/*
+	 * If we've got more to write, let's continue. At this point we know we
+	 * are starting from the beginning of an eraseblock.
+	 */
+	while (count) {
+		if (count > vol->usable_leb_size)
+			len = vol->usable_leb_size;
+		else
+			len = count;
+
+		err = copy_from_user(vol->upd_buf, buf, len);
+		if (err)
+			return -EFAULT;
+
+		if (len == vol->usable_leb_size ||
+		    vol->upd_received + len == vol->upd_bytes) {
+			err = write_leb(ubi, vol, lnum, vol->upd_buf,
+					len, vol->upd_ebs);
+			if (err)
+				break;
+		}
+
+		vol->upd_received += len;
+		count -= len;
+		lnum += 1;
+		buf += len;
+	}
+
+	ubi_assert(vol->upd_received <= vol->upd_bytes);
+	if (vol->upd_received == vol->upd_bytes) {
+		err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL);
+		if (err)
+			return err;
+		/* The update is finished, clear the update marker */
+		err = clear_update_marker(ubi, vol, vol->upd_bytes);
+		if (err)
+			return err;
+		vol->updating = 0;
+		err = to_write;
+		vfree(vol->upd_buf);
+	}
+
+	return err;
+}
+
+/**
+ * ubi_more_leb_change_data - accept more data for atomic LEB change.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ * @buf: write data (user-space memory buffer)
+ * @count: how much bytes to write
+ *
+ * This function accepts more data to the volume which is being under the
+ * "atomic LEB change" operation. It may be called arbitrary number of times
+ * until all data arrives. This function returns %0 in case of success, number
+ * of bytes written during the last call if the whole "atomic LEB change"
+ * operation has been successfully finished, and a negative error code in case
+ * of failure.
+ */
+int ubi_more_leb_change_data(struct ubi_device *ubi, struct ubi_volume *vol,
+			     const void __user *buf, int count)
+{
+	int err;
+
+	dbg_gen("write %d of %lld bytes, %lld already passed",
+		count, vol->upd_bytes, vol->upd_received);
+
+	if (ubi->ro_mode)
+		return -EROFS;
+
+	if (vol->upd_received + count > vol->upd_bytes)
+		count = vol->upd_bytes - vol->upd_received;
+
+	err = copy_from_user(vol->upd_buf + vol->upd_received, buf, count);
+	if (err)
+		return -EFAULT;
+
+	vol->upd_received += count;
+
+	if (vol->upd_received == vol->upd_bytes) {
+		int len = ALIGN((int)vol->upd_bytes, ubi->min_io_size);
+
+		memset(vol->upd_buf + vol->upd_bytes, 0xFF,
+		       len - vol->upd_bytes);
+		len = ubi_calc_data_len(ubi, vol->upd_buf, len);
+		err = ubi_eba_atomic_leb_change(ubi, vol, vol->ch_lnum,
+						vol->upd_buf, len);
+		if (err)
+			return err;
+	}
+
+	ubi_assert(vol->upd_received <= vol->upd_bytes);
+	if (vol->upd_received == vol->upd_bytes) {
+		vol->changing_leb = 0;
+		err = count;
+		vfree(vol->upd_buf);
+	}
+
+	return err;
+}