158 lines
3.6 KiB
C
158 lines
3.6 KiB
C
/*
|
|
* Common code to handle map devices which are simple RAM
|
|
* (C) 2000 Red Hat. GPL'd.
|
|
*/
|
|
|
|
#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 unsigned long mapram_unmapped_area(struct mtd_info *, unsigned long,
|
|
unsigned long, unsigned long);
|
|
|
|
|
|
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->get_unmapped_area = mapram_unmapped_area;
|
|
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;
|
|
}
|
|
|
|
|
|
/*
|
|
* Allow NOMMU mmap() to directly map the device (if not NULL)
|
|
* - return the address to which the offset maps
|
|
* - return -ENOSYS to indicate refusal to do the mapping
|
|
*/
|
|
static unsigned long mapram_unmapped_area(struct mtd_info *mtd,
|
|
unsigned long len,
|
|
unsigned long offset,
|
|
unsigned long flags)
|
|
{
|
|
struct map_info *map = mtd->priv;
|
|
return (unsigned long) map->virt + offset;
|
|
}
|
|
|
|
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");
|