xref: /openbmc/linux/drivers/mtd/mtdblock_ro.c (revision 22246614)
1 /*
2  * $Id: mtdblock_ro.c,v 1.19 2004/11/16 18:28:59 dwmw2 Exp $
3  *
4  * (C) 2003 David Woodhouse <dwmw2@infradead.org>
5  *
6  * Simple read-only (writable only for RAM) mtdblock driver
7  */
8 
9 #include <linux/init.h>
10 #include <linux/slab.h>
11 #include <linux/mtd/mtd.h>
12 #include <linux/mtd/blktrans.h>
13 
14 static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
15 			      unsigned long block, char *buf)
16 {
17 	size_t retlen;
18 
19 	if (dev->mtd->read(dev->mtd, (block * 512), 512, &retlen, buf))
20 		return 1;
21 	return 0;
22 }
23 
24 static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
25 			      unsigned long block, char *buf)
26 {
27 	size_t retlen;
28 
29 	if (dev->mtd->write(dev->mtd, (block * 512), 512, &retlen, buf))
30 		return 1;
31 	return 0;
32 }
33 
34 static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
35 {
36 	struct mtd_blktrans_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);
37 
38 	if (!dev)
39 		return;
40 
41 	dev->mtd = mtd;
42 	dev->devnum = mtd->index;
43 
44 	dev->size = mtd->size >> 9;
45 	dev->tr = tr;
46 	dev->readonly = 1;
47 
48 	add_mtd_blktrans_dev(dev);
49 }
50 
51 static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
52 {
53 	del_mtd_blktrans_dev(dev);
54 	kfree(dev);
55 }
56 
57 static struct mtd_blktrans_ops mtdblock_tr = {
58 	.name		= "mtdblock",
59 	.major		= 31,
60 	.part_bits	= 0,
61 	.blksize 	= 512,
62 	.readsect	= mtdblock_readsect,
63 	.writesect	= mtdblock_writesect,
64 	.add_mtd	= mtdblock_add_mtd,
65 	.remove_dev	= mtdblock_remove_dev,
66 	.owner		= THIS_MODULE,
67 };
68 
69 static int __init mtdblock_init(void)
70 {
71 	return register_mtd_blktrans(&mtdblock_tr);
72 }
73 
74 static void __exit mtdblock_exit(void)
75 {
76 	deregister_mtd_blktrans(&mtdblock_tr);
77 }
78 
79 module_init(mtdblock_init);
80 module_exit(mtdblock_exit);
81 
82 MODULE_LICENSE("GPL");
83 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
84 MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices");
85