GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / mtd / mtdblock_ro.c
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
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
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
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 (mtd_type_is_nand(mtd))
50                 pr_warn("%s: MTD device '%s' is NAND, please consider using UBI block devices instead.\n",
51                         tr->name, mtd->name);
52
53         if (add_mtd_blktrans_dev(dev))
54                 kfree(dev);
55 }
56
57 static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
58 {
59         del_mtd_blktrans_dev(dev);
60 }
61
62 static struct mtd_blktrans_ops mtdblock_tr = {
63         .name           = "mtdblock",
64         .major          = MTD_BLOCK_MAJOR,
65         .part_bits      = 0,
66         .blksize        = 512,
67         .readsect       = mtdblock_readsect,
68         .writesect      = mtdblock_writesect,
69         .add_mtd        = mtdblock_add_mtd,
70         .remove_dev     = mtdblock_remove_dev,
71         .owner          = THIS_MODULE,
72 };
73
74 module_mtd_blktrans(mtdblock_tr);
75
76 MODULE_LICENSE("GPL");
77 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
78 MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices");