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

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Copyright (c) International Business Machines Corp., 2006
   4 *
   5 * Author: Artem Bityutskiy (Битюцкий Артём)
   6 */
   7
   8/* Here we keep miscellaneous functions which are used all over the UBI code */
   9
  10#include <log.h>
  11#include <malloc.h>
  12#include <ubi_uboot.h>
  13#include "ubi.h"
  14
  15/**
  16 * calc_data_len - calculate how much real data is stored in a buffer.
  17 * @ubi: UBI device description object
  18 * @buf: a buffer with the contents of the physical eraseblock
  19 * @length: the buffer length
  20 *
  21 * This function calculates how much "real data" is stored in @buf and returnes
  22 * the length. Continuous 0xFF bytes at the end of the buffer are not
  23 * considered as "real data".
  24 */
  25int ubi_calc_data_len(const struct ubi_device *ubi, const void *buf,
  26                      int length)
  27{
  28        int i;
  29
  30        ubi_assert(!(length & (ubi->min_io_size - 1)));
  31
  32        for (i = length - 1; i >= 0; i--)
  33                if (((const uint8_t *)buf)[i] != 0xFF)
  34                        break;
  35
  36        /* The resulting length must be aligned to the minimum flash I/O size */
  37        length = ALIGN(i + 1, ubi->min_io_size);
  38        return length;
  39}
  40
  41/**
  42 * ubi_check_volume - check the contents of a static volume.
  43 * @ubi: UBI device description object
  44 * @vol_id: ID of the volume to check
  45 *
  46 * This function checks if static volume @vol_id is corrupted by fully reading
  47 * it and checking data CRC. This function returns %0 if the volume is not
  48 * corrupted, %1 if it is corrupted and a negative error code in case of
  49 * failure. Dynamic volumes are not checked and zero is returned immediately.
  50 */
  51int ubi_check_volume(struct ubi_device *ubi, int vol_id)
  52{
  53        void *buf;
  54        int err = 0, i;
  55        struct ubi_volume *vol = ubi->volumes[vol_id];
  56
  57        if (vol->vol_type != UBI_STATIC_VOLUME)
  58                return 0;
  59
  60        buf = vmalloc(vol->usable_leb_size);
  61        if (!buf)
  62                return -ENOMEM;
  63
  64        for (i = 0; i < vol->used_ebs; i++) {
  65                int size;
  66
  67                cond_resched();
  68
  69                if (i == vol->used_ebs - 1)
  70                        size = vol->last_eb_bytes;
  71                else
  72                        size = vol->usable_leb_size;
  73
  74                err = ubi_eba_read_leb(ubi, vol, i, buf, 0, size, 1);
  75                if (err) {
  76                        if (mtd_is_eccerr(err))
  77                                err = 1;
  78                        break;
  79                }
  80        }
  81
  82        vfree(buf);
  83        return err;
  84}
  85
  86/**
  87 * ubi_update_reserved - update bad eraseblock handling accounting data.
  88 * @ubi: UBI device description object
  89 *
  90 * This function calculates the gap between current number of PEBs reserved for
  91 * bad eraseblock handling and the required level of PEBs that must be
  92 * reserved, and if necessary, reserves more PEBs to fill that gap, according
  93 * to availability. Should be called with ubi->volumes_lock held.
  94 */
  95void ubi_update_reserved(struct ubi_device *ubi)
  96{
  97        int need = ubi->beb_rsvd_level - ubi->beb_rsvd_pebs;
  98
  99        if (need <= 0 || ubi->avail_pebs == 0)
 100                return;
 101
 102        need = min_t(int, need, ubi->avail_pebs);
 103        ubi->avail_pebs -= need;
 104        ubi->rsvd_pebs += need;
 105        ubi->beb_rsvd_pebs += need;
 106        ubi_msg(ubi, "reserved more %d PEBs for bad PEB handling", need);
 107}
 108
 109/**
 110 * ubi_calculate_reserved - calculate how many PEBs must be reserved for bad
 111 * eraseblock handling.
 112 * @ubi: UBI device description object
 113 */
 114void ubi_calculate_reserved(struct ubi_device *ubi)
 115{
 116        /*
 117         * Calculate the actual number of PEBs currently needed to be reserved
 118         * for future bad eraseblock handling.
 119         */
 120        ubi->beb_rsvd_level = ubi->bad_peb_limit - ubi->bad_peb_count;
 121        if (ubi->beb_rsvd_level < 0) {
 122                ubi->beb_rsvd_level = 0;
 123                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)",
 124                         ubi->bad_peb_count, ubi->bad_peb_limit);
 125        }
 126}
 127
 128/**
 129 * ubi_check_pattern - check if buffer contains only a certain byte pattern.
 130 * @buf: buffer to check
 131 * @patt: the pattern to check
 132 * @size: buffer size in bytes
 133 *
 134 * This function returns %1 in there are only @patt bytes in @buf, and %0 if
 135 * something else was also found.
 136 */
 137int ubi_check_pattern(const void *buf, uint8_t patt, int size)
 138{
 139        int i;
 140
 141        for (i = 0; i < size; i++)
 142                if (((const uint8_t *)buf)[i] != patt)
 143                        return 0;
 144        return 1;
 145}
 146