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
mtdblock_readsect(struct mtd_blktrans_dev * dev,unsigned long block,char * buf)15 static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
16 unsigned long block, char *buf)
17 {
18 size_t retlen;
19
20 if (mtd_read(dev->mtd, (block * 512), 512, &retlen, buf))
21 return 1;
22 return 0;
23 }
24
mtdblock_writesect(struct mtd_blktrans_dev * dev,unsigned long block,char * buf)25 static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
26 unsigned long block, char *buf)
27 {
28 size_t retlen;
29
30 if (mtd_write(dev->mtd, (block * 512), 512, &retlen, buf))
31 return 1;
32 return 0;
33 }
34
mtdblock_add_mtd(struct mtd_blktrans_ops * tr,struct mtd_info * mtd)35 static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
36 {
37 struct mtd_blktrans_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);
38
39 if (!dev)
40 return;
41
42 dev->mtd = mtd;
43 dev->devnum = mtd->index;
44
45 dev->size = mtd->size >> 9;
46 dev->tr = tr;
47 dev->readonly = 1;
48
49 if (add_mtd_blktrans_dev(dev))
50 kfree(dev);
51 }
52
mtdblock_remove_dev(struct mtd_blktrans_dev * dev)53 static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
54 {
55 del_mtd_blktrans_dev(dev);
56 }
57
58 static struct mtd_blktrans_ops mtdblock_tr = {
59 .name = "mtdblock",
60 .major = MTD_BLOCK_MAJOR,
61 .part_bits = 0,
62 .blksize = 512,
63 .readsect = mtdblock_readsect,
64 .writesect = mtdblock_writesect,
65 .add_mtd = mtdblock_add_mtd,
66 .remove_dev = mtdblock_remove_dev,
67 .owner = THIS_MODULE,
68 };
69
mtdblock_init(void)70 static int __init mtdblock_init(void)
71 {
72 return register_mtd_blktrans(&mtdblock_tr);
73 }
74
mtdblock_exit(void)75 static void __exit mtdblock_exit(void)
76 {
77 deregister_mtd_blktrans(&mtdblock_tr);
78 }
79
80 module_init(mtdblock_init);
81 module_exit(mtdblock_exit);
82
83 MODULE_LICENSE("GPL");
84 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
85 MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices");
86