| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 = kmalloc(sizeof(*dev), GFP_KERNEL); |
| 37 | |
| 38 | if (!dev) |
| 39 | return; |
| 40 | |
| 41 | memset(dev, 0, sizeof(*dev)); |
| 42 | |
| 43 | dev->mtd = mtd; |
| 44 | dev->devnum = mtd->index; |
| 45 | dev->blksize = 512; |
| 46 | dev->size = mtd->size >> 9; |
| 47 | dev->tr = tr; |
| 48 | if ((mtd->flags & (MTD_CLEAR_BITS|MTD_SET_BITS|MTD_WRITEABLE)) != |
| 49 | (MTD_CLEAR_BITS|MTD_SET_BITS|MTD_WRITEABLE)) |
| 50 | dev->readonly = 1; |
| 51 | |
| 52 | add_mtd_blktrans_dev(dev); |
| 53 | } |
| 54 | |
| 55 | static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev) |
| 56 | { |
| 57 | del_mtd_blktrans_dev(dev); |
| 58 | kfree(dev); |
| 59 | } |
| 60 | |
| 61 | static struct mtd_blktrans_ops mtdblock_tr = { |
| 62 | .name = "mtdblock", |
| 63 | .major = 31, |
| 64 | .part_bits = 0, |
| 65 | .readsect = mtdblock_readsect, |
| 66 | .writesect = mtdblock_writesect, |
| 67 | .add_mtd = mtdblock_add_mtd, |
| 68 | .remove_dev = mtdblock_remove_dev, |
| 69 | .owner = THIS_MODULE, |
| 70 | }; |
| 71 | |
| 72 | static int __init mtdblock_init(void) |
| 73 | { |
| 74 | return register_mtd_blktrans(&mtdblock_tr); |
| 75 | } |
| 76 | |
| 77 | static void __exit mtdblock_exit(void) |
| 78 | { |
| 79 | deregister_mtd_blktrans(&mtdblock_tr); |
| 80 | } |
| 81 | |
| 82 | module_init(mtdblock_init); |
| 83 | module_exit(mtdblock_exit); |
| 84 | |
| 85 | MODULE_LICENSE("GPL"); |
| 86 | MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); |
| 87 | MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices"); |