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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;
}
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