1// SPDX-License-Identifier: GPL-2.0
2/*
3 * 2017 by Marek Beh��n <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
17int 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