1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (c) International Business Machines Corp., 2006
4 *
5 * Author: Artem Bityutskiy (���������������� ����������)
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