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