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