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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