1 /* 2 * Common code to handle map devices which are simple RAM 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/mtd/mtd.h> 15 #include <linux/mtd/map.h> 16 17 18 static int mapram_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *); 19 static int mapram_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *); 20 static int mapram_erase (struct mtd_info *, struct erase_info *); 21 static void mapram_nop (struct mtd_info *); 22 static struct mtd_info *map_ram_probe(struct map_info *map); 23 static int mapram_point (struct mtd_info *mtd, loff_t from, size_t len, 24 size_t *retlen, void **virt, resource_size_t *phys); 25 static int mapram_unpoint(struct mtd_info *mtd, loff_t from, size_t len); 26 27 28 static struct mtd_chip_driver mapram_chipdrv = { 29 .probe = map_ram_probe, 30 .name = "map_ram", 31 .module = THIS_MODULE 32 }; 33 34 static struct mtd_info *map_ram_probe(struct map_info *map) 35 { 36 struct mtd_info *mtd; 37 38 /* Check the first byte is RAM */ 39 #if 0 40 map_write8(map, 0x55, 0); 41 if (map_read8(map, 0) != 0x55) 42 return NULL; 43 44 map_write8(map, 0xAA, 0); 45 if (map_read8(map, 0) != 0xAA) 46 return NULL; 47 48 /* Check the last byte is RAM */ 49 map_write8(map, 0x55, map->size-1); 50 if (map_read8(map, map->size-1) != 0x55) 51 return NULL; 52 53 map_write8(map, 0xAA, map->size-1); 54 if (map_read8(map, map->size-1) != 0xAA) 55 return NULL; 56 #endif 57 /* OK. It seems to be RAM. */ 58 59 mtd = kzalloc(sizeof(*mtd), GFP_KERNEL); 60 if (!mtd) 61 return NULL; 62 63 map->fldrv = &mapram_chipdrv; 64 mtd->priv = map; 65 mtd->name = map->name; 66 mtd->type = MTD_RAM; 67 mtd->size = map->size; 68 mtd->_erase = mapram_erase; 69 mtd->_read = mapram_read; 70 mtd->_write = mapram_write; 71 mtd->_panic_write = mapram_write; 72 mtd->_point = mapram_point; 73 mtd->_sync = mapram_nop; 74 mtd->_unpoint = mapram_unpoint; 75 mtd->flags = MTD_CAP_RAM; 76 mtd->writesize = 1; 77 78 mtd->erasesize = PAGE_SIZE; 79 while(mtd->size & (mtd->erasesize - 1)) 80 mtd->erasesize >>= 1; 81 82 __module_get(THIS_MODULE); 83 return mtd; 84 } 85 86 static int mapram_point(struct mtd_info *mtd, loff_t from, size_t len, 87 size_t *retlen, void **virt, resource_size_t *phys) 88 { 89 struct map_info *map = mtd->priv; 90 91 if (!map->virt) 92 return -EINVAL; 93 *virt = map->virt + from; 94 if (phys) 95 *phys = map->phys + from; 96 *retlen = len; 97 return 0; 98 } 99 100 static int mapram_unpoint(struct mtd_info *mtd, loff_t from, size_t len) 101 { 102 return 0; 103 } 104 105 static int mapram_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf) 106 { 107 struct map_info *map = mtd->priv; 108 109 map_copy_from(map, buf, from, len); 110 *retlen = len; 111 return 0; 112 } 113 114 static int mapram_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf) 115 { 116 struct map_info *map = mtd->priv; 117 118 map_copy_to(map, to, buf, len); 119 *retlen = len; 120 return 0; 121 } 122 123 static int mapram_erase (struct mtd_info *mtd, struct erase_info *instr) 124 { 125 /* Yeah, it's inefficient. Who cares? It's faster than a _real_ 126 flash erase. */ 127 struct map_info *map = mtd->priv; 128 map_word allff; 129 unsigned long i; 130 131 allff = map_word_ff(map); 132 for (i=0; i<instr->len; i += map_bankwidth(map)) 133 map_write(map, allff, instr->addr + i); 134 return 0; 135 } 136 137 static void mapram_nop(struct mtd_info *mtd) 138 { 139 /* Nothing to see here */ 140 } 141 142 static int __init map_ram_init(void) 143 { 144 register_mtd_chip_driver(&mapram_chipdrv); 145 return 0; 146 } 147 148 static void __exit map_ram_exit(void) 149 { 150 unregister_mtd_chip_driver(&mapram_chipdrv); 151 } 152 153 module_init(map_ram_init); 154 module_exit(map_ram_exit); 155 156 MODULE_LICENSE("GPL"); 157 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 158 MODULE_DESCRIPTION("MTD chip driver for RAM chips"); 159