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 int err; 20 21 err = mtd_read(dev->mtd, (block * 512), 512, &retlen, buf); 22 if (err && !mtd_is_bitflip(err)) 23 return 1; 24 return 0; 25 } 26 27 static int mtdblock_writesect(struct mtd_blktrans_dev *dev, 28 unsigned long block, char *buf) 29 { 30 size_t retlen; 31 32 if (mtd_write(dev->mtd, (block * 512), 512, &retlen, buf)) 33 return 1; 34 return 0; 35 } 36 37 static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd) 38 { 39 struct mtd_blktrans_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL); 40 41 if (!dev) 42 return; 43 44 dev->mtd = mtd; 45 dev->devnum = mtd->index; 46 47 dev->size = mtd->size >> 9; 48 dev->tr = tr; 49 dev->readonly = 1; 50 51 if (mtd_type_is_nand(mtd)) 52 pr_warn_ratelimited("%s: MTD device '%s' is NAND, please consider using UBI block devices instead.\n", 53 tr->name, mtd->name); 54 55 if (add_mtd_blktrans_dev(dev)) 56 kfree(dev); 57 } 58 59 static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev) 60 { 61 del_mtd_blktrans_dev(dev); 62 } 63 64 static struct mtd_blktrans_ops mtdblock_tr = { 65 .name = "mtdblock", 66 .major = MTD_BLOCK_MAJOR, 67 .part_bits = 0, 68 .blksize = 512, 69 .readsect = mtdblock_readsect, 70 .writesect = mtdblock_writesect, 71 .add_mtd = mtdblock_add_mtd, 72 .remove_dev = mtdblock_remove_dev, 73 .owner = THIS_MODULE, 74 }; 75 76 module_mtd_blktrans(mtdblock_tr); 77 78 MODULE_LICENSE("GPL"); 79 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 80 MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices"); 81