/* * Common code to handle map devices which are simple RAM * (C) 2000 Red Hat. GPL'd. * $Id: map_ram.c,v 1.22 2005/01/05 18:05:12 dwmw2 Exp $ */ #include <linux/module.h> #include <linux/types.h> #include <linux/kernel.h> #include <asm/io.h> #include <asm/byteorder.h> #include <linux/errno.h> #include <linux/slab.h> #include <linux/init.h> #include <linux/mtd/mtd.h> #include <linux/mtd/map.h> #include <linux/mtd/compatmac.h> 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 struct mtd_info *map_ram_probe(struct map_info *map); static struct mtd_chip_driver mapram_chipdrv = { .probe = map_ram_probe, .name = "map_ram", .module = THIS_MODULE }; static struct mtd_info *map_ram_probe(struct map_info *map) { struct mtd_info *mtd; /* Check the first byte is RAM */ #if 0 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; #endif /* OK. It seems to be RAM. */ mtd = kzalloc(sizeof(*mtd), GFP_KERNEL); if (!mtd) return NULL; map->fldrv = &mapram_chipdrv; mtd->priv = map; mtd->name = map->name; mtd->type = MTD_RAM; mtd->size = map->size; mtd->erase = mapram_erase; mtd->read = mapram_read; mtd->write = mapram_write; mtd->sync = mapram_nop; mtd->flags = MTD_CAP_RAM; mtd->writesize = 1; mtd->erasesize = PAGE_SIZE; while(mtd->size & (mtd->erasesize - 1)) mtd->erasesize >>= 1; __module_get(THIS_MODULE); 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 = 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 = 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 = mtd->priv; map_word allff; unsigned long i; allff = map_word_ff(map); for (i=0; i<instr->len; i += map_bankwidth(map)) map_write(map, allff, instr->addr + i); instr->state = MTD_ERASE_DONE; mtd_erase_callback(instr); return 0; } static void mapram_nop(struct mtd_info *mtd) { /* Nothing to see here */ } static int __init map_ram_init(void) { register_mtd_chip_driver(&mapram_chipdrv); return 0; } static void __exit map_ram_exit(void) { unregister_mtd_chip_driver(&mapram_chipdrv); } module_init(map_ram_init); module_exit(map_ram_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); MODULE_DESCRIPTION("MTD chip driver for RAM chips");