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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Simple read-only (writable only for RAM) mtdblock driver4 *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 15static 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 27static 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 37static 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 59static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)60{61 del_mtd_blktrans_dev(dev);62}63 64static 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 76module_mtd_blktrans(mtdblock_tr);77 78MODULE_LICENSE("GPL");79MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");80MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices");81