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  */
  24 int 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  */
  50 int 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                 if (i == vol->used_ebs - 1)
  67                         size = vol->last_eb_bytes;
  68                 else
  69                         size = vol->usable_leb_size;
  70
  71                 err = ubi_eba_read_leb(ubi, vol, i, buf, 0, size, 1);
  72                 if (err) {
  73                         if (mtd_is_eccerr(err))
  74                                 err = 1;
  75                         break;
  76                 }
  77         }
  78
  79         vfree(buf);
  80         return err;
  81 }
  82
  83 /**
  84  * ubi_update_reserved - update bad eraseblock handling accounting data.
  85  * @ubi: UBI device description object
  86  *
  87  * This function calculates the gap between current number of PEBs reserved for
  88  * bad eraseblock handling and the required level of PEBs that must be
  89  * reserved, and if necessary, reserves more PEBs to fill that gap, according
  90  * to availability. Should be called with ubi->volumes_lock held.
  91  */
  92 void ubi_update_reserved(struct ubi_device *ubi)
  93 {
  94         int need = ubi->beb_rsvd_level - ubi->beb_rsvd_pebs;
  95
  96         if (need <= 0 || ubi->avail_pebs == 0)
  97                 return;
  98
  99         need = min_t(int, need, ubi->avail_pebs);
 100         ubi->avail_pebs -= need;
 101         ubi->rsvd_pebs += need;
 102         ubi->beb_rsvd_pebs += need;
 103         ubi_msg("reserved more %d PEBs for bad PEB handling", need);
 104 }
 105
 106 /**
 107  * ubi_calculate_reserved - calculate how many PEBs must be reserved for bad
 108  * eraseblock handling.
 109  * @ubi: UBI device description object
 110  */
 111 void ubi_calculate_reserved(struct ubi_device *ubi)
 112 {
 113         /*
 114          * Calculate the actual number of PEBs currently needed to be reserved
 115          * for future bad eraseblock handling.
 116          */
 117         ubi->beb_rsvd_level = ubi->bad_peb_limit - ubi->bad_peb_count;
 118         if (ubi->beb_rsvd_level < 0) {
 119                 ubi->beb_rsvd_level = 0;
 120                 ubi_warn("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)",
 121                          ubi->bad_peb_count, ubi->bad_peb_limit);
 122         }
 123 }
 124
 125 /**
 126  * ubi_check_pattern - check if buffer contains only a certain byte pattern.
 127  * @buf: buffer to check
 128  * @patt: the pattern to check
 129  * @size: buffer size in bytes
 130  *
 131  * This function returns %1 in there are only @patt bytes in @buf, and %0 if
 132  * something else was also found.
 133  */
 134 int ubi_check_pattern(const void *buf, uint8_t patt, int size)
 135 {
 136         int i;
 137
 138         for (i = 0; i < size; i++)
 139                 if (((const uint8_t *)buf)[i] != patt)
 140                         return 0;
 141         return 1;
 142 }