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 static int maprom_point (struct mtd_info *mtd, loff_t from, size_t len, 26 size_t *retlen, void **virt, resource_size_t *phys); 27 static int maprom_unpoint(struct mtd_info *mtd, loff_t from, size_t len); 28 29 30 static struct mtd_chip_driver maprom_chipdrv = { 31 .probe = map_rom_probe, 32 .name = "map_rom", 33 .module = THIS_MODULE 34 }; 35 36 static unsigned int default_erasesize(struct map_info *map) 37 { 38 const __be32 *erase_size = NULL; 39 40 erase_size = of_get_property(map->device_node, "erase-size", NULL); 41 42 return !erase_size ? map->size : be32_to_cpu(*erase_size); 43 } 44 45 static struct mtd_info *map_rom_probe(struct map_info *map) 46 { 47 struct mtd_info *mtd; 48 49 mtd = kzalloc(sizeof(*mtd), GFP_KERNEL); 50 if (!mtd) 51 return NULL; 52 53 map->fldrv = &maprom_chipdrv; 54 mtd->priv = map; 55 mtd->name = map->name; 56 mtd->type = MTD_ROM; 57 mtd->size = map->size; 58 mtd->_get_unmapped_area = maprom_unmapped_area; 59 mtd->_point = maprom_point; 60 mtd->_unpoint = maprom_unpoint; 61 mtd->_read = maprom_read; 62 mtd->_write = maprom_write; 63 mtd->_sync = maprom_nop; 64 mtd->_erase = maprom_erase; 65 mtd->flags = MTD_CAP_ROM; 66 mtd->erasesize = default_erasesize(map); 67 mtd->writesize = 1; 68 mtd->writebufsize = 1; 69 70 __module_get(THIS_MODULE); 71 return mtd; 72 } 73 74 75 /* 76 * Allow NOMMU mmap() to directly map the device (if not NULL) 77 * - return the address to which the offset maps 78 * - return -ENOSYS to indicate refusal to do the mapping 79 */ 80 static unsigned long maprom_unmapped_area(struct mtd_info *mtd, 81 unsigned long len, 82 unsigned long offset, 83 unsigned long flags) 84 { 85 struct map_info *map = mtd->priv; 86 return (unsigned long) map->virt + offset; 87 } 88 89 static int maprom_point(struct mtd_info *mtd, loff_t from, size_t len, 90 size_t *retlen, void **virt, resource_size_t *phys) 91 { 92 struct map_info *map = mtd->priv; 93 94 if (!map->virt) 95 return -EINVAL; 96 *virt = map->virt + from; 97 if (phys) 98 *phys = map->phys + from; 99 *retlen = len; 100 return 0; 101 } 102 103 static int maprom_unpoint(struct mtd_info *mtd, loff_t from, size_t len) 104 { 105 return 0; 106 } 107 108 static int maprom_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf) 109 { 110 struct map_info *map = mtd->priv; 111 112 map_copy_from(map, buf, from, len); 113 *retlen = len; 114 return 0; 115 } 116 117 static void maprom_nop(struct mtd_info *mtd) 118 { 119 /* Nothing to see here */ 120 } 121 122 static int maprom_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf) 123 { 124 return -EROFS; 125 } 126 127 static int maprom_erase (struct mtd_info *mtd, struct erase_info *info) 128 { 129 /* We do our best 8) */ 130 return -EROFS; 131 } 132 133 static int __init map_rom_init(void) 134 { 135 register_mtd_chip_driver(&maprom_chipdrv); 136 return 0; 137 } 138 139 static void __exit map_rom_exit(void) 140 { 141 unregister_mtd_chip_driver(&maprom_chipdrv); 142 } 143 144 module_init(map_rom_init); 145 module_exit(map_rom_exit); 146 147 MODULE_LICENSE("GPL"); 148 MODULE_AUTHOR("David Woodhouse <[email protected]>"); 149 MODULE_DESCRIPTION("MTD chip driver for ROM chips"); 150