/* * Common code to handle map devices which are simple RAM * (C) 2000 Red Hat. GPL'd. * $Id: map_ram.c,v 1.2 2000/07/03 10:01:38 dwmw2 Exp $ */ #include #include #include #include #include #include #include #include static int mapram_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *); static int mapram_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *); static int mapram_erase (struct mtd_info *, struct erase_info *); static void mapram_nop (struct mtd_info *); static const char im_name[] = "map_ram_probe"; /* This routine is made available to other mtd code via * inter_module_register. It must only be accessed through * inter_module_get which will bump the use count of this module. The * addresses passed back in mtd are valid as long as the use count of * this module is non-zero, i.e. between inter_module_get and * inter_module_put. Keith Owens 29 Oct 2000. */ static struct mtd_info *map_ram_probe(struct map_info *map) { struct mtd_info *mtd; /* Check the first byte is RAM */ map->write8(map, 0x55, 0); if (map->read8(map, 0) != 0x55) return NULL; map->write8(map, 0xAA, 0); if (map->read8(map, 0) != 0xAA) return NULL; /* Check the last byte is RAM */ map->write8(map, 0x55, map->size-1); if (map->read8(map, map->size-1) != 0x55) return NULL; map->write8(map, 0xAA, map->size-1); if (map->read8(map, map->size-1) != 0xAA) return NULL; /* OK. It seems to be RAM. */ mtd = kmalloc(sizeof(*mtd), GFP_KERNEL); if (!mtd) return NULL; memset(mtd, 0, sizeof(*mtd)); map->fldrv_destroy = mapram_nop; mtd->priv = map; mtd->name = map->name; mtd->type = MTD_RAM; mtd->erasesize = 0x10000; mtd->size = map->size; mtd->erase = mapram_erase; mtd->read = mapram_read; mtd->write = mapram_write; mtd->sync = mapram_nop; mtd->im_name = im_name; mtd->flags = MTD_CAP_RAM | MTD_VOLATILE; return mtd; } static int mapram_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf) { struct map_info *map = (struct map_info *)mtd->priv; map->copy_from(map, buf, from, len); *retlen = len; return 0; } static int mapram_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf) { struct map_info *map = (struct map_info *)mtd->priv; map->copy_to(map, to, buf, len); *retlen = len; return 0; } static int mapram_erase (struct mtd_info *mtd, struct erase_info *instr) { /* Yeah, it's inefficient. Who cares? It's faster than a _real_ flash erase. */ struct map_info *map = (struct map_info *)mtd->priv; unsigned long i; for (i=0; ilen; i++) map->write8(map, 0xFF, instr->addr + i); if (instr->callback) instr->callback(instr); return 0; } static void mapram_nop(struct mtd_info *mtd) { /* Nothing to see here */ } static int __init map_ram_init(void) { inter_module_register(im_name, THIS_MODULE, &map_ram_probe); return 0; } static void __exit map_ram_exit(void) { inter_module_unregister(im_name); } module_init(map_ram_init); module_exit(map_ram_exit);