1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-or-later
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Simple read-only (writable only for RAM) mtdblock driver
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright © 2001-2010 David Woodhouse <dwmw2@infradead.org>
6*4882a593Smuzhiyun */
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun #include <linux/init.h>
9*4882a593Smuzhiyun #include <linux/slab.h>
10*4882a593Smuzhiyun #include <linux/mtd/mtd.h>
11*4882a593Smuzhiyun #include <linux/mtd/blktrans.h>
12*4882a593Smuzhiyun #include <linux/module.h>
13*4882a593Smuzhiyun #include <linux/major.h>
14*4882a593Smuzhiyun
mtdblock_readsect(struct mtd_blktrans_dev * dev,unsigned long block,char * buf)15*4882a593Smuzhiyun static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
16*4882a593Smuzhiyun unsigned long block, char *buf)
17*4882a593Smuzhiyun {
18*4882a593Smuzhiyun size_t retlen;
19*4882a593Smuzhiyun
20*4882a593Smuzhiyun if (mtd_read(dev->mtd, (block * 512), 512, &retlen, buf))
21*4882a593Smuzhiyun return 1;
22*4882a593Smuzhiyun return 0;
23*4882a593Smuzhiyun }
24*4882a593Smuzhiyun
mtdblock_writesect(struct mtd_blktrans_dev * dev,unsigned long block,char * buf)25*4882a593Smuzhiyun static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
26*4882a593Smuzhiyun unsigned long block, char *buf)
27*4882a593Smuzhiyun {
28*4882a593Smuzhiyun size_t retlen;
29*4882a593Smuzhiyun
30*4882a593Smuzhiyun if (mtd_write(dev->mtd, (block * 512), 512, &retlen, buf))
31*4882a593Smuzhiyun return 1;
32*4882a593Smuzhiyun return 0;
33*4882a593Smuzhiyun }
34*4882a593Smuzhiyun
mtdblock_add_mtd(struct mtd_blktrans_ops * tr,struct mtd_info * mtd)35*4882a593Smuzhiyun static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
36*4882a593Smuzhiyun {
37*4882a593Smuzhiyun struct mtd_blktrans_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun if (!dev)
40*4882a593Smuzhiyun return;
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun dev->mtd = mtd;
43*4882a593Smuzhiyun dev->devnum = mtd->index;
44*4882a593Smuzhiyun
45*4882a593Smuzhiyun dev->size = mtd->size >> 9;
46*4882a593Smuzhiyun dev->tr = tr;
47*4882a593Smuzhiyun dev->readonly = 1;
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun if (add_mtd_blktrans_dev(dev))
50*4882a593Smuzhiyun kfree(dev);
51*4882a593Smuzhiyun }
52*4882a593Smuzhiyun
mtdblock_remove_dev(struct mtd_blktrans_dev * dev)53*4882a593Smuzhiyun static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
54*4882a593Smuzhiyun {
55*4882a593Smuzhiyun del_mtd_blktrans_dev(dev);
56*4882a593Smuzhiyun }
57*4882a593Smuzhiyun
58*4882a593Smuzhiyun static struct mtd_blktrans_ops mtdblock_tr = {
59*4882a593Smuzhiyun .name = "mtdblock",
60*4882a593Smuzhiyun .major = MTD_BLOCK_MAJOR,
61*4882a593Smuzhiyun .part_bits = 0,
62*4882a593Smuzhiyun .blksize = 512,
63*4882a593Smuzhiyun .readsect = mtdblock_readsect,
64*4882a593Smuzhiyun .writesect = mtdblock_writesect,
65*4882a593Smuzhiyun .add_mtd = mtdblock_add_mtd,
66*4882a593Smuzhiyun .remove_dev = mtdblock_remove_dev,
67*4882a593Smuzhiyun .owner = THIS_MODULE,
68*4882a593Smuzhiyun };
69*4882a593Smuzhiyun
mtdblock_init(void)70*4882a593Smuzhiyun static int __init mtdblock_init(void)
71*4882a593Smuzhiyun {
72*4882a593Smuzhiyun return register_mtd_blktrans(&mtdblock_tr);
73*4882a593Smuzhiyun }
74*4882a593Smuzhiyun
mtdblock_exit(void)75*4882a593Smuzhiyun static void __exit mtdblock_exit(void)
76*4882a593Smuzhiyun {
77*4882a593Smuzhiyun deregister_mtd_blktrans(&mtdblock_tr);
78*4882a593Smuzhiyun }
79*4882a593Smuzhiyun
80*4882a593Smuzhiyun module_init(mtdblock_init);
81*4882a593Smuzhiyun module_exit(mtdblock_exit);
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun MODULE_LICENSE("GPL");
84*4882a593Smuzhiyun MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
85*4882a593Smuzhiyun MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices");
86