drivers/mtd/mtdblock_ro.c

   1 /*
   2  * $Id: mtdblock_ro.c,v 1.19 2004/11/16 18:28:59 dwmw2 Exp $
   3  *
   4  * (C) 2003 David Woodhouse <dwmw2@infradead.org>
   5  *
   6  * Simple read-only (writable only for RAM) mtdblock driver
   7  */
   8
   9 #include <linux/init.h>
  10 #include <linux/slab.h>
  11 #include <linux/mtd/mtd.h>
  12 #include <linux/mtd/blktrans.h>
  13
  14 static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
  15                               unsigned long block, char *buf)
  16 {
  17         size_t retlen;
  18
  19         if (dev->mtd->read(dev->mtd, (block * 512), 512, &retlen, buf))
  20                 return 1;
  21         return 0;
  22 }
  23
  24 static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
  25                               unsigned long block, char *buf)
  26 {
  27         size_t retlen;
  28
  29         if (dev->mtd->write(dev->mtd, (block * 512), 512, &retlen, buf))
  30                 return 1;
  31         return 0;
  32 }
  33
  34 static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
  35 {
  36         struct mtd_blktrans_dev *dev = kmalloc(sizeof(*dev), GFP_KERNEL);
  37
  38         if (!dev)
  39                 return;
  40
  41         memset(dev, 0, sizeof(*dev));
  42
  43         dev->mtd = mtd;
  44         dev->devnum = mtd->index;
  45         dev->blksize = 512;
  46         dev->size = mtd->size >> 9;
  47         dev->tr = tr;
  48         dev->readonly = 1;
  49
  50         add_mtd_blktrans_dev(dev);
  51 }
  52
  53 static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
  54 {
  55         del_mtd_blktrans_dev(dev);
  56         kfree(dev);
  57 }
  58
  59 static struct mtd_blktrans_ops mtdblock_tr = {
  60         .name           = "mtdblock",
  61         .major          = 31,
  62         .part_bits      = 0,
  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");