| /* |
| * 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 = kmalloc(sizeof(*mtd), GFP_KERNEL); |
| if (!mtd) |
| return NULL; |
| |
| memset(mtd, 0, sizeof(*mtd)); |
| |
| 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"); |