1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * 2017 by Marek Behún <kabel@kernel.org>
4 *
5 * Derived from code in ext4/dev.c, which was based on reiserfs/dev.c
6 */
7
8 #define LOG_CATEGORY LOGC_CORE
9
10 #include <common.h>
11 #include <blk.h>
12 #include <compiler.h>
13 #include <log.h>
14 #include <part.h>
15 #include <memalign.h>
16
fs_devread(struct blk_desc * blk,struct disk_partition * partition,lbaint_t sector,int byte_offset,int byte_len,char * buf)17 int fs_devread(struct blk_desc *blk, struct disk_partition *partition,
18 lbaint_t sector, int byte_offset, int byte_len, char *buf)
19 {
20 unsigned block_len;
21 int log2blksz;
22 ALLOC_CACHE_ALIGN_BUFFER(char, sec_buf, (blk ? blk->blksz : 0));
23 if (blk == NULL) {
24 log_err("** Invalid Block Device Descriptor (NULL)\n");
25 return 0;
26 }
27 log2blksz = blk->log2blksz;
28
29 /* Check partition boundaries */
30 if ((sector + ((byte_offset + byte_len - 1) >> log2blksz))
31 >= partition->size) {
32 log_debug("read outside partition " LBAFU "\n", sector);
33 return 0;
34 }
35
36 /* Get the read to the beginning of a partition */
37 sector += byte_offset >> log2blksz;
38 byte_offset &= blk->blksz - 1;
39
40 log_debug(" <" LBAFU ", %d, %d>\n", sector, byte_offset, byte_len);
41
42 if (byte_offset != 0) {
43 int readlen;
44 /* read first part which isn't aligned with start of sector */
45 if (blk_dread(blk, partition->start + sector, 1,
46 (void *)sec_buf) != 1) {
47 log_err(" ** %s read error **\n", __func__);
48 return 0;
49 }
50 readlen = min((int)blk->blksz - byte_offset,
51 byte_len);
52 memcpy(buf, sec_buf + byte_offset, readlen);
53 buf += readlen;
54 byte_len -= readlen;
55 sector++;
56 }
57
58 if (byte_len == 0)
59 return 1;
60
61 /* read sector aligned part */
62 block_len = byte_len & ~(blk->blksz - 1);
63
64 if (block_len == 0) {
65 ALLOC_CACHE_ALIGN_BUFFER(u8, p, blk->blksz);
66
67 block_len = blk->blksz;
68 blk_dread(blk, partition->start + sector, 1,
69 (void *)p);
70 memcpy(buf, p, byte_len);
71 return 1;
72 }
73
74 if (blk_dread(blk, partition->start + sector,
75 block_len >> log2blksz, (void *)buf) !=
76 block_len >> log2blksz) {
77 log_err(" ** %s read error - block\n", __func__);
78 return 0;
79 }
80 block_len = byte_len & ~(blk->blksz - 1);
81 buf += block_len;
82 byte_len -= block_len;
83 sector += block_len / blk->blksz;
84
85 if (byte_len != 0) {
86 /* read rest of data which are not in whole sector */
87 if (blk_dread(blk, partition->start + sector, 1,
88 (void *)sec_buf) != 1) {
89 log_err("* %s read error - last part\n", __func__);
90 return 0;
91 }
92 memcpy(buf, sec_buf, byte_len);
93 }
94 return 1;
95 }
96