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 (add_mtd_blktrans_dev(dev)) 50 kfree(dev); 51 } 52 53 static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev) 54 { 55 del_mtd_blktrans_dev(dev); 56 } 57 58 static struct mtd_blktrans_ops mtdblock_tr = { 59 .name = "mtdblock", 60 .major = MTD_BLOCK_MAJOR, 61 .part_bits = 0, 62 .blksize = 512, 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