drivers/mtd/mtdblock_ro.c

   1 /*
   2  * (C) 2003 David Woodhouse <dwmw2@infradead.org>
   3  *
   4  * Simple read-only (writable only for RAM) mtdblock driver
   5  */
   6
   7 #include <linux/init.h>
   8 #include <linux/slab.h>
   9 #include <linux/mtd/mtd.h>
  10 #include <linux/mtd/blktrans.h>
  11
  12 static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
  13                               unsigned long block, char *buf)
  14 {
  15         size_t retlen;
  16
  17         if (dev->mtd->read(dev->mtd, (block * 512), 512, &retlen, buf))
  18                 return 1;
  19         return 0;
  20 }
  21
  22 static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
  23                               unsigned long block, char *buf)
  24 {
  25         size_t retlen;
  26
  27         if (dev->mtd->write(dev->mtd, (block * 512), 512, &retlen, buf))
  28                 return 1;
  29         return 0;
  30 }
  31
  32 static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
  33 {
  34         struct mtd_blktrans_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);
  35
  36         if (!dev)
  37                 return;
  38
  39         dev->mtd = mtd;
  40         dev->devnum = mtd->index;
  41
  42         dev->size = mtd->size >> 9;
  43         dev->tr = tr;
  44         dev->readonly = 1;
  45
  46         add_mtd_blktrans_dev(dev);
  47 }
  48
  49 static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
  50 {
  51         del_mtd_blktrans_dev(dev);
  52         kfree(dev);
  53 }
  54
  55 static struct mtd_blktrans_ops mtdblock_tr = {
  56         .name           = "mtdblock",
  57         .major          = 31,
  58         .part_bits      = 0,
  59         .blksize        = 512,
  60         .readsect       = mtdblock_readsect,
  61         .writesect      = mtdblock_writesect,
  62         .add_mtd        = mtdblock_add_mtd,
  63         .remove_dev     = mtdblock_remove_dev,
  64         .owner          = THIS_MODULE,
  65 };
  66
  67 static int __init mtdblock_init(void)
  68 {
  69         return register_mtd_blktrans(&mtdblock_tr);
  70 }
  71
  72 static void __exit mtdblock_exit(void)
  73 {
  74         deregister_mtd_blktrans(&mtdblock_tr);
  75 }
  76
  77 module_init(mtdblock_init);
  78 module_exit(mtdblock_exit);
  79
  80 MODULE_LICENSE("GPL");
  81 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
  82 MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices");