drivers/mtd/mtdblock_ro.c

   1 /*
   2  * $Id: mtdblock_ro.c,v 1.18 2003/06/23 12:00:08 dwmw2 Exp $
   3  *
   4  * (C) 2003 David Woodhouse <dwmw2@infradead.org>
   5  *
   6  * Simple read-only (writable only for RAM) mtdblock driver
   7  *
   8  * (C) 2002 David McCullough, Added MAGIC_ROM_PTR support
   9  */
  10
  11 #include <linux/init.h>
  12 #include <linux/slab.h>
  13 #include <linux/mtd/mtd.h>
  14 #include <linux/mtd/blktrans.h>
  15
  16 static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
  17                               unsigned long block, char *buf)
  18 {
  19         size_t retlen;
  20
  21         if (dev->mtd->read(dev->mtd, (block * 512), 512, &retlen, buf))
  22                 return 1;
  23         return 0;
  24 }
  25
  26 static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
  27                               unsigned long block, char *buf)
  28 {
  29         size_t retlen;
  30
  31         if (dev->mtd->write(dev->mtd, (block * 512), 512, &retlen, buf))
  32                 return 1;
  33         return 0;
  34 }
  35
  36 static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
  37 {
  38         struct mtd_blktrans_dev *dev = kmalloc(sizeof(*dev), GFP_KERNEL);
  39
  40         if (!dev)
  41                 return;
  42
  43         memset(dev, 0, sizeof(*dev));
  44
  45         dev->mtd = mtd;
  46         dev->devnum = mtd->index;
  47         dev->blksize = 512;
  48         dev->size = mtd->size >> 9;
  49         dev->tr = tr;
  50         if ((mtd->flags & (MTD_CLEAR_BITS|MTD_SET_BITS|MTD_WRITEABLE)) !=
  51             (MTD_CLEAR_BITS|MTD_SET_BITS|MTD_WRITEABLE))
  52                 dev->readonly = 1;
  53
  54         add_mtd_blktrans_dev(dev);
  55 }
  56
  57 #ifdef CONFIG_MAGIC_ROM_PTR
  58 #include <linux/mm.h>
  59 static int
  60 mtdblock_romptr(struct mtd_blktrans_dev *dev, struct vm_area_struct * vma)
  61 {
  62         struct mtd_info *mtd = dev->mtd;
  63         u_char *ptr;
  64         size_t len;
  65
  66         if (!mtd->point /* Can't do it, No function to point to correct addr */
  67
  68         || (*mtd->point)(mtd,vma->vm_pgoff,vma->vm_end-vma->vm_start,&len,&ptr) != 0)
  69                 return -ENOSYS;
  70
  71         vma->vm_start = (unsigned long) ptr;
  72         vma->vm_end = vma->vm_start + len;
  73         return 0;
  74 }
  75 #endif
  76
  77 static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
  78 {
  79         del_mtd_blktrans_dev(dev);
  80         kfree(dev);
  81 }
  82
  83 struct mtd_blktrans_ops mtdblock_tr = {
  84         .name           = "mtdblock",
  85         .major          = 31,
  86         .part_bits      = 0,
  87         .readsect       = mtdblock_readsect,
  88         .writesect      = mtdblock_writesect,
  89         .add_mtd        = mtdblock_add_mtd,
  90         .remove_dev     = mtdblock_remove_dev,
  91         .owner          = THIS_MODULE,
  92 #ifdef CONFIG_MAGIC_ROM_PTR
  93         .romptr         = mtdblock_romptr,
  94 #endif
  95 };
  96
  97 static int __init mtdblock_init(void)
  98 {
  99         return register_mtd_blktrans(&mtdblock_tr);
 100 }
 101
 102 static void __exit mtdblock_exit(void)
 103 {
 104         deregister_mtd_blktrans(&mtdblock_tr);
 105 }
 106
 107 module_init(mtdblock_init);
 108 module_exit(mtdblock_exit);
 109
 110 MODULE_LICENSE("GPL");
 111 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 112 MODULE_DESCRIPTION("Simple read-only block device emulation access to MTD devices");