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 #include <linux/module.h> 27 28 static int mtdblock_readsect(struct mtd_blktrans_dev *dev, 29 unsigned long block, char *buf) 30 { 31 size_t retlen; 32 33 if (mtd_read(dev->mtd, (block * 512), 512, &retlen, buf)) 34 return 1; 35 return 0; 36 } 37 38 static int mtdblock_writesect(struct mtd_blktrans_dev *dev, 39 unsigned long block, char *buf) 40 { 41 size_t retlen; 42 43 if (mtd_write(dev->mtd, (block * 512), 512, &retlen, buf)) 44 return 1; 45 return 0; 46 } 47 48 static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd) 49 { 50 struct mtd_blktrans_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL); 51 52 if (!dev) 53 return; 54 55 dev->mtd = mtd; 56 dev->devnum = mtd->index; 57 58 dev->size = mtd->size >> 9; 59 dev->tr = tr; 60 dev->readonly = 1; 61 62 if (add_mtd_blktrans_dev(dev)) 63 kfree(dev); 64 } 65 66 static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev) 67 { 68 del_mtd_blktrans_dev(dev); 69 } 70 71 static struct mtd_blktrans_ops mtdblock_tr = { 72 .name = "mtdblock", 73 .major = 31, 74 .part_bits = 0, 75 .blksize = 512, 76 .readsect = mtdblock_readsect, 77 .writesect = mtdblock_writesect, 78 .add_mtd = mtdblock_add_mtd, 79 .remove_dev = mtdblock_remove_dev, 80 .owner = THIS_MODULE, 81 }; 82 83 static int __init mtdblock_init(void) 84 { 85 return register_mtd_blktrans(&mtdblock_tr); 86 } 87 88 static void __exit mtdblock_exit(void) 89 { 90 deregister_mtd_blktrans(&mtdblock_tr); 91 } 92 93 module_init(mtdblock_init); 94 module_exit(mtdblock_exit); 95 96 MODULE_LICENSE("GPL"); 97 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 98 MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices"); 99