release/src-rt-6.x.4708/linux/linux-2.6.36/drivers/mtd/chips/map_rom.c

   1 /*
   2  * Common code to handle map devices which are simple ROM
   3  * (C) 2000 Red Hat. GPL'd.
   4  */
   5
   6 #include <linux/module.h>
   7 #include <linux/types.h>
   8 #include <linux/kernel.h>
   9 #include <asm/io.h>
  10 #include <asm/byteorder.h>
  11 #include <linux/errno.h>
  12 #include <linux/slab.h>
  13 #include <linux/init.h>
  14 #include <linux/mtd/mtd.h>
  15 #include <linux/mtd/map.h>
  16
  17 static int maprom_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *);
  18 static int maprom_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
  19 static void maprom_nop (struct mtd_info *);
  20 static struct mtd_info *map_rom_probe(struct map_info *map);
  21 static int maprom_erase (struct mtd_info *mtd, struct erase_info *info);
  22 static unsigned long maprom_unmapped_area(struct mtd_info *, unsigned long,
  23                                           unsigned long, unsigned long);
  24
  25 static struct mtd_chip_driver maprom_chipdrv = {
  26         .probe  = map_rom_probe,
  27         .name   = "map_rom",
  28         .module = THIS_MODULE
  29 };
  30
  31 static struct mtd_info *map_rom_probe(struct map_info *map)
  32 {
  33         struct mtd_info *mtd;
  34
  35         mtd = kzalloc(sizeof(*mtd), GFP_KERNEL);
  36         if (!mtd)
  37                 return NULL;
  38
  39         map->fldrv = &maprom_chipdrv;
  40         mtd->priv = map;
  41         mtd->name = map->name;
  42         mtd->type = MTD_ROM;
  43         mtd->size = map->size;
  44         mtd->get_unmapped_area = maprom_unmapped_area;
  45         mtd->read = maprom_read;
  46         mtd->write = maprom_write;
  47         mtd->sync = maprom_nop;
  48         mtd->erase = maprom_erase;
  49         mtd->flags = MTD_CAP_ROM;
  50         mtd->erasesize = map->size;
  51         mtd->writesize = 1;
  52
  53         __module_get(THIS_MODULE);
  54         return mtd;
  55 }
  56
  57
  58 /*
  59  * Allow NOMMU mmap() to directly map the device (if not NULL)
  60  * - return the address to which the offset maps
  61  * - return -ENOSYS to indicate refusal to do the mapping
  62  */
  63 static unsigned long maprom_unmapped_area(struct mtd_info *mtd,
  64                                           unsigned long len,
  65                                           unsigned long offset,
  66                                           unsigned long flags)
  67 {
  68         struct map_info *map = mtd->priv;
  69         return (unsigned long) map->virt + offset;
  70 }
  71
  72 static int maprom_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
  73 {
  74         struct map_info *map = mtd->priv;
  75
  76         map_copy_from(map, buf, from, len);
  77         *retlen = len;
  78         return 0;
  79 }
  80
  81 static void maprom_nop(struct mtd_info *mtd)
  82 {
  83         /* Nothing to see here */
  84 }
  85
  86 static int maprom_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf)
  87 {
  88         printk(KERN_NOTICE "maprom_write called\n");
  89         return -EIO;
  90 }
  91
  92 static int maprom_erase (struct mtd_info *mtd, struct erase_info *info)
  93 {
  94         /* We do our best 8) */
  95         return -EROFS;
  96 }
  97
  98 static int __init map_rom_init(void)
  99 {
 100         register_mtd_chip_driver(&maprom_chipdrv);
 101         return 0;
 102 }
 103
 104 static void __exit map_rom_exit(void)
 105 {
 106         unregister_mtd_chip_driver(&maprom_chipdrv);
 107 }
 108
 109 module_init(map_rom_init);
 110 module_exit(map_rom_exit);
 111
 112 MODULE_LICENSE("GPL");
 113 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 114 MODULE_DESCRIPTION("MTD chip driver for ROM chips");