1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Simple read-only (writable only for RAM) mtdblock driver 4 * 5 * Copyright © 2001-2010 David Woodhouse <dwmw2@infradead.org> 6 */ 7 8 #include <linux/init.h> 9 #include <linux/slab.h> 10 #include <linux/mtd/mtd.h> 11 #include <linux/mtd/blktrans.h> 12 #include <linux/module.h> 13 #include <linux/major.h> 14 15 static int mtdblock_readsect(struct mtd_blktrans_dev *dev, 16 unsigned long block, char *buf) 17 { 18 size_t retlen; 19 20 if (mtd_read(dev->mtd, (block * 512), 512, &retlen, buf)) 21 return 1; 22 return 0; 23 } 24 25 static int mtdblock_writesect(struct mtd_blktrans_dev *dev, 26 unsigned long block, char *buf) 27 { 28 size_t retlen; 29 30 if (mtd_write(dev->mtd, (block * 512), 512, &retlen, buf)) 31 return 1; 32 return 0; 33 } 34 35 static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd) 36 { 37 struct mtd_blktrans_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL); 38 39 if (!dev) 40 return; 41 42 dev->mtd = mtd; 43 dev->devnum = mtd->index; 44 45 dev->size = mtd->size >> 9; 46 dev->tr = tr; 47 dev->readonly = 1; 48 49 if (mtd_type_is_nand(mtd)) 50 pr_warn("%s: MTD device '%s' is NAND, please consider using UBI block devices instead.\n", 51 tr->name, mtd->name); 52 53 if (add_mtd_blktrans_dev(dev)) 54 kfree(dev); 55 } 56 57 static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev) 58 { 59 del_mtd_blktrans_dev(dev); 60 } 61 62 static struct mtd_blktrans_ops mtdblock_tr = { 63 .name = "mtdblock", 64 .major = MTD_BLOCK_MAJOR, 65 .part_bits = 0, 66 .blksize = 512, 67 .readsect = mtdblock_readsect, 68 .writesect = mtdblock_writesect, 69 .add_mtd = mtdblock_add_mtd, 70 .remove_dev = mtdblock_remove_dev, 71 .owner = THIS_MODULE, 72 }; 73 74 module_mtd_blktrans(mtdblock_tr); 75 76 MODULE_LICENSE("GPL"); 77 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 78 MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices"); 79