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 27 static int mtdblock_readsect(struct mtd_blktrans_dev *dev, 28 unsigned long block, char *buf) 29 { 30 size_t retlen; 31 32 if (dev->mtd->read(dev->mtd, (block * 512), 512, &retlen, buf)) 33 return 1; 34 return 0; 35 } 36 37 static int mtdblock_writesect(struct mtd_blktrans_dev *dev, 38 unsigned long block, char *buf) 39 { 40 size_t retlen; 41 42 if (dev->mtd->write(dev->mtd, (block * 512), 512, &retlen, buf)) 43 return 1; 44 return 0; 45 } 46 47 static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd) 48 { 49 struct mtd_blktrans_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL); 50 51 if (!dev) 52 return; 53 54 dev->mtd = mtd; 55 dev->devnum = mtd->index; 56 57 dev->size = mtd->size >> 9; 58 dev->tr = tr; 59 dev->readonly = 1; 60 61 if (add_mtd_blktrans_dev(dev)) 62 kfree(dev); 63 } 64 65 static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev) 66 { 67 del_mtd_blktrans_dev(dev); 68 } 69 70 static struct mtd_blktrans_ops mtdblock_tr = { 71 .name = "mtdblock", 72 .major = 31, 73 .part_bits = 0, 74 .blksize = 512, 75 .readsect = mtdblock_readsect, 76 .writesect = mtdblock_writesect, 77 .add_mtd = mtdblock_add_mtd, 78 .remove_dev = mtdblock_remove_dev, 79 .owner = THIS_MODULE, 80 }; 81 82 static int __init mtdblock_init(void) 83 { 84 return register_mtd_blktrans(&mtdblock_tr); 85 } 86 87 static void __exit mtdblock_exit(void) 88 { 89 deregister_mtd_blktrans(&mtdblock_tr); 90 } 91 92 module_init(mtdblock_init); 93 module_exit(mtdblock_exit); 94 95 MODULE_LICENSE("GPL"); 96 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 97 MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices"); 98