1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Simple read-only (writable only for RAM) mtdblock driver |
4 | * |
5 | * Copyright © 2001-2010 David Woodhouse <dwmw2@infradead.org> |
6 | */ |
7 | |
8 | #include <linux/init.h> |
9 | #include <linux/slab.h> |
10 | #include <linux/mtd/mtd.h> |
11 | #include <linux/mtd/blktrans.h> |
12 | #include <linux/module.h> |
13 | #include <linux/major.h> |
14 | |
15 | static int mtdblock_readsect(struct mtd_blktrans_dev *dev, |
16 | unsigned long block, char *buf) |
17 | { |
18 | size_t retlen; |
19 | int err; |
20 | |
21 | err = mtd_read(mtd: dev->mtd, from: (block * 512), len: 512, retlen: &retlen, buf); |
22 | if (err && !mtd_is_bitflip(err)) |
23 | return 1; |
24 | return 0; |
25 | } |
26 | |
27 | static int mtdblock_writesect(struct mtd_blktrans_dev *dev, |
28 | unsigned long block, char *buf) |
29 | { |
30 | size_t retlen; |
31 | |
32 | if (mtd_write(mtd: dev->mtd, to: (block * 512), len: 512, retlen: &retlen, buf)) |
33 | return 1; |
34 | return 0; |
35 | } |
36 | |
37 | static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd) |
38 | { |
39 | struct mtd_blktrans_dev *dev = kzalloc(size: sizeof(*dev), GFP_KERNEL); |
40 | |
41 | if (!dev) |
42 | return; |
43 | |
44 | dev->mtd = mtd; |
45 | dev->devnum = mtd->index; |
46 | |
47 | dev->size = mtd->size >> 9; |
48 | dev->tr = tr; |
49 | dev->readonly = 1; |
50 | |
51 | if (mtd_type_is_nand(mtd)) |
52 | pr_warn_ratelimited("%s: MTD device '%s' is NAND, please consider using UBI block devices instead.\n" , |
53 | tr->name, mtd->name); |
54 | |
55 | if (add_mtd_blktrans_dev(dev)) |
56 | kfree(objp: dev); |
57 | } |
58 | |
59 | static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev) |
60 | { |
61 | del_mtd_blktrans_dev(dev); |
62 | } |
63 | |
64 | static struct mtd_blktrans_ops mtdblock_tr = { |
65 | .name = "mtdblock" , |
66 | .major = MTD_BLOCK_MAJOR, |
67 | .part_bits = 0, |
68 | .blksize = 512, |
69 | .readsect = mtdblock_readsect, |
70 | .writesect = mtdblock_writesect, |
71 | .add_mtd = mtdblock_add_mtd, |
72 | .remove_dev = mtdblock_remove_dev, |
73 | .owner = THIS_MODULE, |
74 | }; |
75 | |
76 | module_mtd_blktrans(mtdblock_tr); |
77 | |
78 | MODULE_LICENSE("GPL" ); |
79 | MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>" ); |
80 | MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices" ); |
81 | |