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-rw-r--r--kernel/drivers/mtd/ubi/misc.c155
1 files changed, 155 insertions, 0 deletions
diff --git a/kernel/drivers/mtd/ubi/misc.c b/kernel/drivers/mtd/ubi/misc.c
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+++ b/kernel/drivers/mtd/ubi/misc.c
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+/*
+ * 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.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;
+
+ cond_resched();
+
+ 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 (mtd_is_eccerr(err))
+ err = 1;
+ break;
+ }
+ }
+
+ vfree(buf);
+ return err;
+}
+
+/**
+ * ubi_update_reserved - update bad eraseblock handling accounting data.
+ * @ubi: UBI device description object
+ *
+ * This function calculates the gap between current number of PEBs reserved for
+ * bad eraseblock handling and the required level of PEBs that must be
+ * reserved, and if necessary, reserves more PEBs to fill that gap, according
+ * to availability. Should be called with ubi->volumes_lock held.
+ */
+void ubi_update_reserved(struct ubi_device *ubi)
+{
+ int need = ubi->beb_rsvd_level - ubi->beb_rsvd_pebs;
+
+ if (need <= 0 || ubi->avail_pebs == 0)
+ return;
+
+ need = min_t(int, need, ubi->avail_pebs);
+ ubi->avail_pebs -= need;
+ ubi->rsvd_pebs += need;
+ ubi->beb_rsvd_pebs += need;
+ ubi_msg(ubi, "reserved more %d PEBs for bad PEB handling", need);
+}
+
+/**
+ * ubi_calculate_reserved - calculate how many PEBs must be reserved for bad
+ * eraseblock handling.
+ * @ubi: UBI device description object
+ */
+void ubi_calculate_reserved(struct ubi_device *ubi)
+{
+ /*
+ * Calculate the actual number of PEBs currently needed to be reserved
+ * for future bad eraseblock handling.
+ */
+ ubi->beb_rsvd_level = ubi->bad_peb_limit - ubi->bad_peb_count;
+ if (ubi->beb_rsvd_level < 0) {
+ ubi->beb_rsvd_level = 0;
+ ubi_warn(ubi, "number of bad PEBs (%d) is above the expected limit (%d), not reserving any PEBs for bad PEB handling, will use available PEBs (if any)",
+ ubi->bad_peb_count, ubi->bad_peb_limit);
+ }
+}
+
+/**
+ * ubi_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.
+ */
+int ubi_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;
+}