1 /* 2 * Copyright (c) International Business Machines Corp., 2006 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See 12 * the GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 17 * 18 * Author: Artem Bityutskiy (Битюцкий Артём) 19 */ 20 21 /* Here we keep miscellaneous functions which are used all over the UBI code */ 22 23 #include "ubi.h" 24 25 /** 26 * calc_data_len - calculate how much real data is stored in a buffer. 27 * @ubi: UBI device description object 28 * @buf: a buffer with the contents of the physical eraseblock 29 * @length: the buffer length 30 * 31 * This function calculates how much "real data" is stored in @buf and returnes 32 * the length. Continuous 0xFF bytes at the end of the buffer are not 33 * considered as "real data". 34 */ 35 int ubi_calc_data_len(const struct ubi_device *ubi, const void *buf, 36 int length) 37 { 38 int i; 39 40 ubi_assert(!(length & (ubi->min_io_size - 1))); 41 42 for (i = length - 1; i >= 0; i--) 43 if (((const uint8_t *)buf)[i] != 0xFF) 44 break; 45 46 /* The resulting length must be aligned to the minimum flash I/O size */ 47 length = ALIGN(i + 1, ubi->min_io_size); 48 return length; 49 } 50 51 /** 52 * ubi_check_volume - check the contents of a static volume. 53 * @ubi: UBI device description object 54 * @vol_id: ID of the volume to check 55 * 56 * This function checks if static volume @vol_id is corrupted by fully reading 57 * it and checking data CRC. This function returns %0 if the volume is not 58 * corrupted, %1 if it is corrupted and a negative error code in case of 59 * failure. Dynamic volumes are not checked and zero is returned immediately. 60 */ 61 int ubi_check_volume(struct ubi_device *ubi, int vol_id) 62 { 63 void *buf; 64 int err = 0, i; 65 struct ubi_volume *vol = ubi->volumes[vol_id]; 66 67 if (vol->vol_type != UBI_STATIC_VOLUME) 68 return 0; 69 70 buf = vmalloc(vol->usable_leb_size); 71 if (!buf) 72 return -ENOMEM; 73 74 for (i = 0; i < vol->used_ebs; i++) { 75 int size; 76 77 if (i == vol->used_ebs - 1) 78 size = vol->last_eb_bytes; 79 else 80 size = vol->usable_leb_size; 81 82 err = ubi_eba_read_leb(ubi, vol, i, buf, 0, size, 1); 83 if (err) { 84 if (mtd_is_eccerr(err)) 85 err = 1; 86 break; 87 } 88 } 89 90 vfree(buf); 91 return err; 92 } 93 94 /** 95 * ubi_update_reserved - update bad eraseblock handling accounting data. 96 * @ubi: UBI device description object 97 * 98 * This function calculates the gap between current number of PEBs reserved for 99 * bad eraseblock handling and the required level of PEBs that must be 100 * reserved, and if necessary, reserves more PEBs to fill that gap, according 101 * to availability. Should be called with ubi->volumes_lock held. 102 */ 103 void ubi_update_reserved(struct ubi_device *ubi) 104 { 105 int need = ubi->beb_rsvd_level - ubi->beb_rsvd_pebs; 106 107 if (need <= 0 || ubi->avail_pebs == 0) 108 return; 109 110 need = min_t(int, need, ubi->avail_pebs); 111 ubi->avail_pebs -= need; 112 ubi->rsvd_pebs += need; 113 ubi->beb_rsvd_pebs += need; 114 ubi_msg("reserved more %d PEBs for bad PEB handling", need); 115 } 116 117 /** 118 * ubi_calculate_reserved - calculate how many PEBs must be reserved for bad 119 * eraseblock handling. 120 * @ubi: UBI device description object 121 */ 122 void ubi_calculate_reserved(struct ubi_device *ubi) 123 { 124 /* 125 * Calculate the actual number of PEBs currently needed to be reserved 126 * for future bad eraseblock handling. 127 */ 128 ubi->beb_rsvd_level = ubi->bad_peb_limit - ubi->bad_peb_count; 129 if (ubi->beb_rsvd_level < 0) { 130 ubi->beb_rsvd_level = 0; 131 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)", 132 ubi->bad_peb_count, ubi->bad_peb_limit); 133 } 134 } 135 136 /** 137 * ubi_check_pattern - check if buffer contains only a certain byte pattern. 138 * @buf: buffer to check 139 * @patt: the pattern to check 140 * @size: buffer size in bytes 141 * 142 * This function returns %1 in there are only @patt bytes in @buf, and %0 if 143 * something else was also found. 144 */ 145 int ubi_check_pattern(const void *buf, uint8_t patt, int size) 146 { 147 int i; 148 149 for (i = 0; i < size; i++) 150 if (((const uint8_t *)buf)[i] != patt) 151 return 0; 152 return 1; 153 } 154