1 /*
2 * Simple read-only (writable only for RAM) mtdblock driver
3 *
4 * Copyright © 2001-2010 David Woodhouse <dwmw2@infradead.org>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 *
20 */
21
22 #include <linux/init.h>
23 #include <linux/slab.h>
24 #include <linux/mtd/mtd.h>
25 #include <linux/mtd/blktrans.h>
26 #include <linux/module.h>
27 #include <linux/major.h>
28
mtdblock_readsect(struct mtd_blktrans_dev * dev,unsigned long block,char * buf)29 static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
30 unsigned long block, char *buf)
31 {
32 size_t retlen;
33
34 if (mtd_read(dev->mtd, (block * 512), 512, &retlen, buf))
35 return 1;
36 return 0;
37 }
38
mtdblock_writesect(struct mtd_blktrans_dev * dev,unsigned long block,char * buf)39 static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
40 unsigned long block, char *buf)
41 {
42 size_t retlen;
43
44 if (mtd_write(dev->mtd, (block * 512), 512, &retlen, buf))
45 return 1;
46 return 0;
47 }
48
mtdblock_add_mtd(struct mtd_blktrans_ops * tr,struct mtd_info * mtd)49 static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
50 {
51 struct mtd_blktrans_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);
52
53 if (!dev)
54 return;
55
56 dev->mtd = mtd;
57 dev->devnum = mtd->index;
58
59 dev->size = mtd->size >> 9;
60 dev->tr = tr;
61 dev->readonly = 1;
62
63 if (add_mtd_blktrans_dev(dev))
64 kfree(dev);
65 }
66
mtdblock_remove_dev(struct mtd_blktrans_dev * dev)67 static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
68 {
69 del_mtd_blktrans_dev(dev);
70 }
71
72 static struct mtd_blktrans_ops mtdblock_tr = {
73 .name = "mtdblock",
74 .major = MTD_BLOCK_MAJOR,
75 .part_bits = 0,
76 .blksize = 512,
77 .readsect = mtdblock_readsect,
78 .writesect = mtdblock_writesect,
79 .add_mtd = mtdblock_add_mtd,
80 .remove_dev = mtdblock_remove_dev,
81 .owner = THIS_MODULE,
82 };
83
mtdblock_init(void)84 static int __init mtdblock_init(void)
85 {
86 return register_mtd_blktrans(&mtdblock_tr);
87 }
88
mtdblock_exit(void)89 static void __exit mtdblock_exit(void)
90 {
91 deregister_mtd_blktrans(&mtdblock_tr);
92 }
93
94 module_init(mtdblock_init);
95 module_exit(mtdblock_exit);
96
97 MODULE_LICENSE("GPL");
98 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
99 MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices");
100
