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 dev->readonly = 1; 49 50 add_mtd_blktrans_dev(dev); 51 } 52 53 static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev) 54 { 55 del_mtd_blktrans_dev(dev); 56 kfree(dev); 57 } 58 59 static struct mtd_blktrans_ops mtdblock_tr = { 60 .name = "mtdblock", 61 .major = 31, 62 .part_bits = 0, 63 .readsect = mtdblock_readsect, 64 .writesect = mtdblock_writesect, 65 .add_mtd = mtdblock_add_mtd, 66 .remove_dev = mtdblock_remove_dev, 67 .owner = THIS_MODULE, 68 }; 69 70 static int __init mtdblock_init(void) 71 { 72 return register_mtd_blktrans(&mtdblock_tr); 73 } 74 75 static void __exit mtdblock_exit(void) 76 { 77 deregister_mtd_blktrans(&mtdblock_tr); 78 } 79 80 module_init(mtdblock_init); 81 module_exit(mtdblock_exit); 82 83 MODULE_LICENSE("GPL"); 84 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 85 MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices"); 86