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
15static 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
27static 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
37static 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
59static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
60{
61 del_mtd_blktrans_dev(dev);
62}
63
64static 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
76module_mtd_blktrans(mtdblock_tr);
77
78MODULE_LICENSE("GPL");
79MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
80MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices");
81

source code of linux/drivers/mtd/mtdblock_ro.c