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"); 125