drivers/mtd/mtdblock_ro.c

   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");