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 */ 35int 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 */ 61int 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 (err == -EBADMSG) 85 err = 1; 86 break; 87 } 88 } 89 90 vfree(buf); 91 return err; 92} 93 94/** 95 * ubi_calculate_rsvd_pool - calculate how many PEBs must be reserved for bad 96 * eraseblock handling. 97 * @ubi: UBI device description object 98 */ 99void ubi_calculate_reserved(struct ubi_device *ubi) 100{ 101 ubi->beb_rsvd_level = ubi->good_peb_count/100; 102 ubi->beb_rsvd_level *= CONFIG_MTD_UBI_BEB_RESERVE; 103 if (ubi->beb_rsvd_level < MIN_RESEVED_PEBS) 104 ubi->beb_rsvd_level = MIN_RESEVED_PEBS; 105} 106 107/** 108 * ubi_check_pattern - check if buffer contains only a certain byte pattern. 109 * @buf: buffer to check 110 * @patt: the pattern to check 111 * @size: buffer size in bytes 112 * 113 * This function returns %1 in there are only @patt bytes in @buf, and %0 if 114 * something else was also found. 115 */ 116int ubi_check_pattern(const void *buf, uint8_t patt, int size) 117{ 118 int i; 119 120 for (i = 0; i < size; i++) 121 if (((const uint8_t *)buf)[i] != patt) 122 return 0; 123 return 1; 124} 125