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"); 133