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/of.h>
  15 #include <linux/mtd/mtd.h>
  16 #include <linux/mtd/map.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 int maprom_point (struct mtd_info *mtd, loff_t from, size_t len,
  24                          size_t *retlen, void **virt, resource_size_t *phys);
  25 static int maprom_unpoint(struct mtd_info *mtd, loff_t from, size_t len);
  26
  27
  28 static struct mtd_chip_driver maprom_chipdrv = {
  29         .probe  = map_rom_probe,
  30         .name   = "map_rom",
  31         .module = THIS_MODULE
  32 };
  33
  34 static unsigned int default_erasesize(struct map_info *map)
  35 {
  36         const __be32 *erase_size = NULL;
  37
  38         erase_size = of_get_property(map->device_node, "erase-size", NULL);
  39
  40         return !erase_size ? map->size : be32_to_cpu(*erase_size);
  41 }
  42
  43 static struct mtd_info *map_rom_probe(struct map_info *map)
  44 {
  45         struct mtd_info *mtd;
  46
  47         mtd = kzalloc(sizeof(*mtd), GFP_KERNEL);
  48         if (!mtd)
  49                 return NULL;
  50
  51         map->fldrv = &maprom_chipdrv;
  52         mtd->priv = map;
  53         mtd->name = map->name;
  54         mtd->type = MTD_ROM;
  55         mtd->size = map->size;
  56         mtd->_point = maprom_point;
  57         mtd->_unpoint = maprom_unpoint;
  58         mtd->_read = maprom_read;
  59         mtd->_write = maprom_write;
  60         mtd->_sync = maprom_nop;
  61         mtd->_erase = maprom_erase;
  62         mtd->flags = MTD_CAP_ROM;
  63         mtd->erasesize = default_erasesize(map);
  64         mtd->writesize = 1;
  65         mtd->writebufsize = 1;
  66
  67         __module_get(THIS_MODULE);
  68         return mtd;
  69 }
  70
  71
  72 static int maprom_point(struct mtd_info *mtd, loff_t from, size_t len,
  73                         size_t *retlen, void **virt, resource_size_t *phys)
  74 {
  75         struct map_info *map = mtd->priv;
  76
  77         if (!map->virt)
  78                 return -EINVAL;
  79         *virt = map->virt + from;
  80         if (phys)
  81                 *phys = map->phys + from;
  82         *retlen = len;
  83         return 0;
  84 }
  85
  86 static int maprom_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  87 {
  88         return 0;
  89 }
  90
  91 static int maprom_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
  92 {
  93         struct map_info *map = mtd->priv;
  94
  95         map_copy_from(map, buf, from, len);
  96         *retlen = len;
  97         return 0;
  98 }
  99
 100 static void maprom_nop(struct mtd_info *mtd)
 101 {
 102         /* Nothing to see here */
 103 }
 104
 105 static int maprom_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf)
 106 {
 107         return -EROFS;
 108 }
 109
 110 static int maprom_erase (struct mtd_info *mtd, struct erase_info *info)
 111 {
 112         /* We do our best 8) */
 113         return -EROFS;
 114 }
 115
 116 static int __init map_rom_init(void)
 117 {
 118         register_mtd_chip_driver(&maprom_chipdrv);
 119         return 0;
 120 }
 121
 122 static void __exit map_rom_exit(void)
 123 {
 124         unregister_mtd_chip_driver(&maprom_chipdrv);
 125 }
 126
 127 module_init(map_rom_init);
 128 module_exit(map_rom_exit);
 129
 130 MODULE_LICENSE("GPL");
 131 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 132 MODULE_DESCRIPTION("MTD chip driver for ROM chips");