LXR linux/drivers/mtd/mtdblock

   1/*
   2 * Simple read-only (writable only for RAM) mtdblock driver
   3 *
   4 * Copyright © 2001-2010 David Woodhouse <dwmw2@infradead.org>
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19 *
  20 */
  21
  22#include <linux/init.h>
  23#include <linux/slab.h>
  24#include <linux/mtd/mtd.h>
  25#include <linux/mtd/blktrans.h>
  26#include <linux/module.h>
  27#include <linux/major.h>
  28
  29static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
  30                              unsigned long block, char *buf)
  31{
  32        size_t retlen;
  33
  34        if (mtd_read(dev->mtd, (block * 512), 512, &retlen, buf))
  35                return 1;
  36        return 0;
  37}
  38
  39static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
  40                              unsigned long block, char *buf)
  41{
  42        size_t retlen;
  43
  44        if (mtd_write(dev->mtd, (block * 512), 512, &retlen, buf))
  45                return 1;
  46        return 0;
  47}
  48
  49static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
  50{
  51        struct mtd_blktrans_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);
  52
  53        if (!dev)
  54                return;
  55
  56        dev->mtd = mtd;
  57        dev->devnum = mtd->index;
  58
  59        dev->size = mtd->size >> 9;
  60        dev->tr = tr;
  61        dev->readonly = 1;
  62
  63        if (add_mtd_blktrans_dev(dev))
  64                kfree(dev);
  65}
  66
  67static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
  68{
  69        del_mtd_blktrans_dev(dev);
  70}
  71
  72static struct mtd_blktrans_ops mtdblock_tr = {
  73        .name           = "mtdblock",
  74        .major          = MTD_BLOCK_MAJOR,
  75        .part_bits      = 0,
  76        .blksize        = 512,
  77        .readsect       = mtdblock_readsect,
  78        .writesect      = mtdblock_writesect,
  79        .add_mtd        = mtdblock_add_mtd,
  80        .remove_dev     = mtdblock_remove_dev,
  81        .owner          = THIS_MODULE,
  82};
  83
  84static int __init mtdblock_init(void)
  85{
  86        return register_mtd_blktrans(&mtdblock_tr);
  87}
  88
  89static void __exit mtdblock_exit(void)
  90{
  91        deregister_mtd_blktrans(&mtdblock_tr);
  92}
  93
  94module_init(mtdblock_init);
  95module_exit(mtdblock_exit);
  96
  97MODULE_LICENSE("GPL");
  98MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
  99MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices");
 100