drivers/mtd/mtdblock_ro.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * Simple read-only (writable only for RAM) mtdblock driver
0004  *
0005  * Copyright © 2001-2010 David Woodhouse <dwmw2@infradead.org>
0006  */
0007
0008 #include <linux/init.h>
0009 #include <linux/slab.h>
0010 #include <linux/mtd/mtd.h>
0011 #include <linux/mtd/blktrans.h>
0012 #include <linux/module.h>
0013 #include <linux/major.h>
0014
0015 static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
0016                   unsigned long block, char *buf)
0017 {
0018     size_t retlen;
0019
0020     if (mtd_read(dev->mtd, (block * 512), 512, &retlen, buf))
0021         return 1;
0022     return 0;
0023 }
0024
0025 static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
0026                   unsigned long block, char *buf)
0027 {
0028     size_t retlen;
0029
0030     if (mtd_write(dev->mtd, (block * 512), 512, &retlen, buf))
0031         return 1;
0032     return 0;
0033 }
0034
0035 static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
0036 {
0037     struct mtd_blktrans_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);
0038
0039     if (!dev)
0040         return;
0041
0042     dev->mtd = mtd;
0043     dev->devnum = mtd->index;
0044
0045     dev->size = mtd->size >> 9;
0046     dev->tr = tr;
0047     dev->readonly = 1;
0048
0049     if (mtd_type_is_nand(mtd))
0050         pr_warn("%s: MTD device '%s' is NAND, please consider using UBI block devices instead.\n",
0051             tr->name, mtd->name);
0052
0053     if (add_mtd_blktrans_dev(dev))
0054         kfree(dev);
0055 }
0056
0057 static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
0058 {
0059     del_mtd_blktrans_dev(dev);
0060 }
0061
0062 static struct mtd_blktrans_ops mtdblock_tr = {
0063     .name       = "mtdblock",
0064     .major      = MTD_BLOCK_MAJOR,
0065     .part_bits  = 0,
0066     .blksize    = 512,
0067     .readsect   = mtdblock_readsect,
0068     .writesect  = mtdblock_writesect,
0069     .add_mtd    = mtdblock_add_mtd,
0070     .remove_dev = mtdblock_remove_dev,
0071     .owner      = THIS_MODULE,
0072 };
0073
0074 module_mtd_blktrans(mtdblock_tr);
0075
0076 MODULE_LICENSE("GPL");
0077 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
0078 MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices");