LXR uboot/drivers/mtd/ubi/misc.c

   1/*
   2 * Copyright (c) International Business Machines Corp., 2006
   3 *
   4 * SPDX-License-Identifier:     GPL-2.0+
   5 *
   6 * Author: Artem Bityutskiy (Битюцкий Артём)
   7 */
   8
   9/* Here we keep miscellaneous functions which are used all over the UBI code */
  10
  11#include <ubi_uboot.h>
  12#include "ubi.h"
  13
  14/**
  15 * calc_data_len - calculate how much real data is stored in a buffer.
  16 * @ubi: UBI device description object
  17 * @buf: a buffer with the contents of the physical eraseblock
  18 * @length: the buffer length
  19 *
  20 * This function calculates how much "real data" is stored in @buf and returnes
  21 * the length. Continuous 0xFF bytes at the end of the buffer are not
  22 * considered as "real data".
  23 */
  24int ubi_calc_data_len(const struct ubi_device *ubi, const void *buf,
  25                      int length)
  26{
  27        int i;
  28
  29        ubi_assert(!(length & (ubi->min_io_size - 1)));
  30
  31        for (i = length - 1; i >= 0; i--)
  32                if (((const uint8_t *)buf)[i] != 0xFF)
  33                        break;
  34
  35        /* The resulting length must be aligned to the minimum flash I/O size */
  36        length = ALIGN(i + 1, ubi->min_io_size);
  37        return length;
  38}
  39
  40/**
  41 * ubi_check_volume - check the contents of a static volume.
  42 * @ubi: UBI device description object
  43 * @vol_id: ID of the volume to check
  44 *
  45 * This function checks if static volume @vol_id is corrupted by fully reading
  46 * it and checking data CRC. This function returns %0 if the volume is not
  47 * corrupted, %1 if it is corrupted and a negative error code in case of
  48 * failure. Dynamic volumes are not checked and zero is returned immediately.
  49 */
  50int ubi_check_volume(struct ubi_device *ubi, int vol_id)
  51{
  52        void *buf;
  53        int err = 0, i;
  54        struct ubi_volume *vol = ubi->volumes[vol_id];
  55
  56        if (vol->vol_type != UBI_STATIC_VOLUME)
  57                return 0;
  58
  59        buf = vmalloc(vol->usable_leb_size);
  60        if (!buf)
  61                return -ENOMEM;
  62
  63        for (i = 0; i < vol->used_ebs; i++) {
  64                int size;
  65
  66                cond_resched();
  67
  68                if (i == vol->used_ebs - 1)
  69                        size = vol->last_eb_bytes;
  70                else
  71                        size = vol->usable_leb_size;
  72
  73                err = ubi_eba_read_leb(ubi, vol, i, buf, 0, size, 1);
  74                if (err) {
  75                        if (mtd_is_eccerr(err))
  76                                err = 1;
  77                        break;
  78                }
  79        }
  80
  81        vfree(buf);
  82        return err;
  83}
  84
  85/**
  86 * ubi_update_reserved - update bad eraseblock handling accounting data.
  87 * @ubi: UBI device description object
  88 *
  89 * This function calculates the gap between current number of PEBs reserved for
  90 * bad eraseblock handling and the required level of PEBs that must be
  91 * reserved, and if necessary, reserves more PEBs to fill that gap, according
  92 * to availability. Should be called with ubi->volumes_lock held.
  93 */
  94void ubi_update_reserved(struct ubi_device *ubi)
  95{
  96        int need = ubi->beb_rsvd_level - ubi->beb_rsvd_pebs;
  97
  98        if (need <= 0 || ubi->avail_pebs == 0)
  99                return;
 100
 101        need = min_t(int, need, ubi->avail_pebs);
 102        ubi->avail_pebs -= need;
 103        ubi->rsvd_pebs += need;
 104        ubi->beb_rsvd_pebs += need;
 105        ubi_msg(ubi, "reserved more %d PEBs for bad PEB handling", need);
 106}
 107
 108/**
 109 * ubi_calculate_reserved - calculate how many PEBs must be reserved for bad
 110 * eraseblock handling.
 111 * @ubi: UBI device description object
 112 */
 113void ubi_calculate_reserved(struct ubi_device *ubi)
 114{
 115        /*
 116         * Calculate the actual number of PEBs currently needed to be reserved
 117         * for future bad eraseblock handling.
 118         */
 119        ubi->beb_rsvd_level = ubi->bad_peb_limit - ubi->bad_peb_count;
 120        if (ubi->beb_rsvd_level < 0) {
 121                ubi->beb_rsvd_level = 0;
 122                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)",
 123                         ubi->bad_peb_count, ubi->bad_peb_limit);
 124        }
 125}
 126
 127/**
 128 * ubi_check_pattern - check if buffer contains only a certain byte pattern.
 129 * @buf: buffer to check
 130 * @patt: the pattern to check
 131 * @size: buffer size in bytes
 132 *
 133 * This function returns %1 in there are only @patt bytes in @buf, and %0 if
 134 * something else was also found.
 135 */
 136int ubi_check_pattern(const void *buf, uint8_t patt, int size)
 137{
 138        int i;
 139
 140        for (i = 0; i < size; i++)
 141                if (((const uint8_t *)buf)[i] != patt)
 142                        return 0;
 143        return 1;
 144}
 145