[deliverable/linux.git] / drivers / mtd / chips / map_ram.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");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Common code to handle map devices which are simple RAM
	3	* (C) 2000 Red Hat. GPL'd.
1da177e4 LT	4	*/
	5
	6	#include <linux/module.h>
	7	#include <linux/types.h>
	8	#include <linux/kernel.h>
	9	#include <asm/io.h>
	10	#include <asm/byteorder.h>
	11	#include <linux/errno.h>
	12	#include <linux/slab.h>
	13	#include <linux/init.h>
	14	#include <linux/mtd/mtd.h>
	15	#include <linux/mtd/map.h>
1da177e4 LT	16
	17
	18	static int mapram_read (struct mtd_info , loff_t, size_t, size_t , u_char *);
	19	static int mapram_write (struct mtd_info , loff_t, size_t, size_t , const u_char *);
	20	static int mapram_erase (struct mtd_info , struct erase_info );
	21	static void mapram_nop (struct mtd_info *);
	22	static struct mtd_info map_ram_probe(struct map_info map);
402d3265 DH	23	static unsigned long mapram_unmapped_area(struct mtd_info *, unsigned long,
402d3265 DH	24	unsigned long, unsigned long);
1da177e4 LT	25
	26
	27	static struct mtd_chip_driver mapram_chipdrv = {
	28	.probe = map_ram_probe,
	29	.name = "map_ram",
	30	.module = THIS_MODULE
	31	};
	32
	33	static struct mtd_info map_ram_probe(struct map_info map)
	34	{
	35	struct mtd_info *mtd;
	36
	37	/* Check the first byte is RAM */
	38	#if 0
	39	map_write8(map, 0x55, 0);
	40	if (map_read8(map, 0) != 0x55)
	41	return NULL;
	42
	43	map_write8(map, 0xAA, 0);
	44	if (map_read8(map, 0) != 0xAA)
	45	return NULL;
	46
	47	/* Check the last byte is RAM */
	48	map_write8(map, 0x55, map->size-1);
	49	if (map_read8(map, map->size-1) != 0x55)
	50	return NULL;
	51
	52	map_write8(map, 0xAA, map->size-1);
	53	if (map_read8(map, map->size-1) != 0xAA)
	54	return NULL;
	55	#endif
	56	/* OK. It seems to be RAM. */
	57
95b93a0c	58	mtd = kzalloc(sizeof(*mtd), GFP_KERNEL);
1da177e4 LT	59	if (!mtd)
	60	return NULL;
	61
1da177e4 LT	62	map->fldrv = &mapram_chipdrv;
	63	mtd->priv = map;
	64	mtd->name = map->name;
21c8db9e	65	mtd->type = MTD_RAM;
1da177e4	66	mtd->size = map->size;
3c3c10bb AB	67	mtd->_erase = mapram_erase;
	68	mtd->_get_unmapped_area = mapram_unmapped_area;
	69	mtd->_read = mapram_read;
	70	mtd->_write = mapram_write;
	71	mtd->_sync = mapram_nop;
a6c591ed	72	mtd->flags = MTD_CAP_RAM;
17ffc7ba	73	mtd->writesize = 1;
1da177e4 LT	74
	75	mtd->erasesize = PAGE_SIZE;
	76	while(mtd->size & (mtd->erasesize - 1))
	77	mtd->erasesize >>= 1;
	78
	79	__module_get(THIS_MODULE);
	80	return mtd;
	81	}
	82
	83
402d3265 DH	84	/*
	85	* Allow NOMMU mmap() to directly map the device (if not NULL)
	86	* - return the address to which the offset maps
	87	* - return -ENOSYS to indicate refusal to do the mapping
	88	*/
	89	static unsigned long mapram_unmapped_area(struct mtd_info *mtd,
	90	unsigned long len,
	91	unsigned long offset,
	92	unsigned long flags)
	93	{
	94	struct map_info *map = mtd->priv;
	95	return (unsigned long) map->virt + offset;
	96	}
	97
1da177e4 LT	98	static int mapram_read (struct mtd_info mtd, loff_t from, size_t len, size_t retlen, u_char *buf)
	99	{
	100	struct map_info *map = mtd->priv;
	101
	102	map_copy_from(map, buf, from, len);
	103	*retlen = len;
	104	return 0;
	105	}
	106
	107	static int mapram_write (struct mtd_info mtd, loff_t to, size_t len, size_t retlen, const u_char *buf)
	108	{
	109	struct map_info *map = mtd->priv;
	110
	111	map_copy_to(map, to, buf, len);
	112	*retlen = len;
	113	return 0;
	114	}
	115
	116	static int mapram_erase (struct mtd_info mtd, struct erase_info instr)
	117	{
	118	/* Yeah, it's inefficient. Who cares? It's faster than a _real_
	119	flash erase. */
	120	struct map_info *map = mtd->priv;
	121	map_word allff;
	122	unsigned long i;
	123
	124	allff = map_word_ff(map);
1da177e4 LT	125	for (i=0; i<instr->len; i += map_bankwidth(map))
1da177e4 LT	126	map_write(map, allff, instr->addr + i);
1da177e4	127	instr->state = MTD_ERASE_DONE;
1da177e4	128	mtd_erase_callback(instr);
1da177e4 LT	129	return 0;
	130	}
	131
	132	static void mapram_nop(struct mtd_info *mtd)
	133	{
	134	/* Nothing to see here */
	135	}
	136
	137	static int __init map_ram_init(void)
	138	{
	139	register_mtd_chip_driver(&mapram_chipdrv);
	140	return 0;
	141	}
	142
	143	static void __exit map_ram_exit(void)
	144	{
	145	unregister_mtd_chip_driver(&mapram_chipdrv);
	146	}
	147
	148	module_init(map_ram_init);
	149	module_exit(map_ram_exit);
	150
	151	MODULE_LICENSE("GPL");
	152	MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
	153	MODULE_DESCRIPTION("MTD chip driver for RAM chips");