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 #include <linux/major.h> 28 29 static int mtdblock_readsect(struct mtd_blktrans_dev *dev, 30 unsigned long block, char *buf) 31 { 32 size_t retlen; 33 34 if (mtd_read(dev->mtd, (block * 512), 512, &retlen, buf)) 35 return 1; 36 return 0; 37 } 38 39 static int mtdblock_writesect(struct mtd_blktrans_dev *dev, 40 unsigned long block, char *buf) 41 { 42 size_t retlen; 43 44 if (mtd_write(dev->mtd, (block * 512), 512, &retlen, buf)) 45 return 1; 46 return 0; 47 } 48 49 static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd) 50 { 51 struct mtd_blktrans_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL); 52 53 if (!dev) 54 return; 55 56 dev->mtd = mtd; 57 dev->devnum = mtd->index; 58 59 dev->size = mtd->size >> 9; 60 dev->tr = tr; 61 dev->readonly = 1; 62 63 if (add_mtd_blktrans_dev(dev)) 64 kfree(dev); 65 } 66 67 static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev) 68 { 69 del_mtd_blktrans_dev(dev); 70 } 71 72 static struct mtd_blktrans_ops mtdblock_tr = { 73 .name = "mtdblock", 74 .major = MTD_BLOCK_MAJOR, 75 .part_bits = 0, 76 .blksize = 512, 77 .readsect = mtdblock_readsect, 78 .writesect = mtdblock_writesect, 79 .add_mtd = mtdblock_add_mtd, 80 .remove_dev = mtdblock_remove_dev, 81 .owner = THIS_MODULE, 82 }; 83 84 static int __init mtdblock_init(void) 85 { 86 return register_mtd_blktrans(&mtdblock_tr); 87 } 88 89 static void __exit mtdblock_exit(void) 90 { 91 deregister_mtd_blktrans(&mtdblock_tr); 92 } 93 94 module_init(mtdblock_init); 95 module_exit(mtdblock_exit); 96 97 MODULE_LICENSE("GPL"); 98 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 99 MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices"); 100