diff options
Diffstat (limited to 'drivers/mtd/chips/map_ram.c')
| -rw-r--r-- | drivers/mtd/chips/map_ram.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/drivers/mtd/chips/map_ram.c b/drivers/mtd/chips/map_ram.c new file mode 100644 index 0000000000..e8dd649692 --- /dev/null +++ b/drivers/mtd/chips/map_ram.c @@ -0,0 +1,159 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Common code to handle map devices which are simple RAM + * (C) 2000 Red Hat. + */ + +#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> + + +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 int mapram_point (struct mtd_info *mtd, loff_t from, size_t len, + size_t *retlen, void **virt, resource_size_t *phys); +static int mapram_unpoint(struct mtd_info *mtd, loff_t from, size_t len); + + +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->_panic_write = mapram_write; + mtd->_point = mapram_point; + mtd->_sync = mapram_nop; + mtd->_unpoint = mapram_unpoint; + 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_point(struct mtd_info *mtd, loff_t from, size_t len, + size_t *retlen, void **virt, resource_size_t *phys) +{ + struct map_info *map = mtd->priv; + + if (!map->virt) + return -EINVAL; + *virt = map->virt + from; + if (phys) + *phys = map->phys + from; + *retlen = len; + return 0; +} + +static int mapram_unpoint(struct mtd_info *mtd, loff_t from, size_t len) +{ + return 0; +} + +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); + 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"); |