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 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 unsigned int default_erasesize(struct map_info *map)
  33 {
  34         const __be32 *erase_size = NULL;
  35
  36         erase_size = of_get_property(map->device_node, "erase-size", NULL);
  37
  38         return !erase_size ? map->size : be32_to_cpu(*erase_size);
  39 }
  40
  41 static struct mtd_info *map_rom_probe(struct map_info *map)
  42 {
  43         struct mtd_info *mtd;
  44
  45         mtd = kzalloc(sizeof(*mtd), GFP_KERNEL);
  46         if (!mtd)
  47                 return NULL;
  48
  49         map->fldrv = &maprom_chipdrv;
  50         mtd->priv = map;
  51         mtd->name = map->name;
  52         mtd->type = MTD_ROM;
  53         mtd->size = map->size;
  54         mtd->_get_unmapped_area = maprom_unmapped_area;
  55         mtd->_read = maprom_read;
  56         mtd->_write = maprom_write;
  57         mtd->_sync = maprom_nop;
  58         mtd->_erase = maprom_erase;
  59         mtd->flags = MTD_CAP_ROM;
  60         mtd->erasesize = default_erasesize(map);
  61         mtd->writesize = 1;
  62         mtd->writebufsize = 1;
  63
  64         __module_get(THIS_MODULE);
  65         return mtd;
  66 }
  67
  68
  69 /*
  70  * Allow NOMMU mmap() to directly map the device (if not NULL)
  71  * - return the address to which the offset maps
  72  * - return -ENOSYS to indicate refusal to do the mapping
  73  */
  74 static unsigned long maprom_unmapped_area(struct mtd_info *mtd,
  75                                           unsigned long len,
  76                                           unsigned long offset,
  77                                           unsigned long flags)
  78 {
  79         struct map_info *map = mtd->priv;
  80         return (unsigned long) map->virt + offset;
  81 }
  82
  83 static int maprom_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
  84 {
  85         struct map_info *map = mtd->priv;
  86
  87         map_copy_from(map, buf, from, len);
  88         *retlen = len;
  89         return 0;
  90 }
  91
  92 static void maprom_nop(struct mtd_info *mtd)
  93 {
  94         /* Nothing to see here */
  95 }
  96
  97 static int maprom_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf)
  98 {
  99         return -EROFS;
 100 }
 101
 102 static int maprom_erase (struct mtd_info *mtd, struct erase_info *info)
 103 {
 104         /* We do our best 8) */
 105         return -EROFS;
 106 }
 107
 108 static int __init map_rom_init(void)
 109 {
 110         register_mtd_chip_driver(&maprom_chipdrv);
 111         return 0;
 112 }
 113
 114 static void __exit map_rom_exit(void)
 115 {
 116         unregister_mtd_chip_driver(&maprom_chipdrv);
 117 }
 118
 119 module_init(map_rom_init);
 120 module_exit(map_rom_exit);
 121
 122 MODULE_LICENSE("GPL");
 123 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 124 MODULE_DESCRIPTION("MTD chip driver for ROM chips");