[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>
#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 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>
	16	#include <linux/mtd/compatmac.h>
	17
	18
	19	static int mapram_read (struct mtd_info , loff_t, size_t, size_t , u_char *);
	20	static int mapram_write (struct mtd_info , loff_t, size_t, size_t , const u_char *);
	21	static int mapram_erase (struct mtd_info , struct erase_info );
	22	static void mapram_nop (struct mtd_info *);
	23	static struct mtd_info map_ram_probe(struct map_info map);
402d3265 DH	24	static unsigned long mapram_unmapped_area(struct mtd_info *, unsigned long,
402d3265 DH	25	unsigned long, unsigned long);
1da177e4 LT	26
	27
	28	static struct mtd_chip_driver mapram_chipdrv = {
	29	.probe = map_ram_probe,
	30	.name = "map_ram",
	31	.module = THIS_MODULE
	32	};
	33
	34	static struct mtd_info map_ram_probe(struct map_info map)
	35	{
	36	struct mtd_info *mtd;
	37
	38	/* Check the first byte is RAM */
	39	#if 0
	40	map_write8(map, 0x55, 0);
	41	if (map_read8(map, 0) != 0x55)
	42	return NULL;
	43
	44	map_write8(map, 0xAA, 0);
	45	if (map_read8(map, 0) != 0xAA)
	46	return NULL;
	47
	48	/* Check the last byte is RAM */
	49	map_write8(map, 0x55, map->size-1);
	50	if (map_read8(map, map->size-1) != 0x55)
	51	return NULL;
	52
	53	map_write8(map, 0xAA, map->size-1);
	54	if (map_read8(map, map->size-1) != 0xAA)
	55	return NULL;
	56	#endif
	57	/* OK. It seems to be RAM. */
	58
95b93a0c	59	mtd = kzalloc(sizeof(*mtd), GFP_KERNEL);
1da177e4 LT	60	if (!mtd)
	61	return NULL;
	62
1da177e4 LT	63	map->fldrv = &mapram_chipdrv;
	64	mtd->priv = map;
	65	mtd->name = map->name;
21c8db9e	66	mtd->type = MTD_RAM;
1da177e4 LT	67	mtd->size = map->size;
1da177e4 LT	68	mtd->erase = mapram_erase;
402d3265	69	mtd->get_unmapped_area = mapram_unmapped_area;
1da177e4 LT	70	mtd->read = mapram_read;
	71	mtd->write = mapram_write;
	72	mtd->sync = mapram_nop;
a6c591ed	73	mtd->flags = MTD_CAP_RAM;
17ffc7ba	74	mtd->writesize = 1;
1da177e4 LT	75
	76	mtd->erasesize = PAGE_SIZE;
	77	while(mtd->size & (mtd->erasesize - 1))
	78	mtd->erasesize >>= 1;
	79
	80	__module_get(THIS_MODULE);
	81	return mtd;
	82	}
	83
	84
402d3265 DH	85	/*
	86	* Allow NOMMU mmap() to directly map the device (if not NULL)
	87	* - return the address to which the offset maps
	88	* - return -ENOSYS to indicate refusal to do the mapping
	89	*/
	90	static unsigned long mapram_unmapped_area(struct mtd_info *mtd,
	91	unsigned long len,
	92	unsigned long offset,
	93	unsigned long flags)
	94	{
	95	struct map_info *map = mtd->priv;
	96	return (unsigned long) map->virt + offset;
	97	}
	98
1da177e4 LT	99	static int mapram_read (struct mtd_info mtd, loff_t from, size_t len, size_t retlen, u_char *buf)
	100	{
	101	struct map_info *map = mtd->priv;
	102
	103	map_copy_from(map, buf, from, len);
	104	*retlen = len;
	105	return 0;
	106	}
	107
	108	static int mapram_write (struct mtd_info mtd, loff_t to, size_t len, size_t retlen, const u_char *buf)
	109	{
	110	struct map_info *map = mtd->priv;
	111
	112	map_copy_to(map, to, buf, len);
	113	*retlen = len;
	114	return 0;
	115	}
	116
	117	static int mapram_erase (struct mtd_info mtd, struct erase_info instr)
	118	{
	119	/* Yeah, it's inefficient. Who cares? It's faster than a _real_
	120	flash erase. */
	121	struct map_info *map = mtd->priv;
	122	map_word allff;
	123	unsigned long i;
	124
	125	allff = map_word_ff(map);
	126
	127	for (i=0; i<instr->len; i += map_bankwidth(map))
	128	map_write(map, allff, instr->addr + i);
	129
	130	instr->state = MTD_ERASE_DONE;
	131
	132	mtd_erase_callback(instr);
	133
	134	return 0;
	135	}
	136
	137	static void mapram_nop(struct mtd_info *mtd)
	138	{
	139	/* Nothing to see here */
	140	}
	141
	142	static int __init map_ram_init(void)
	143	{
	144	register_mtd_chip_driver(&mapram_chipdrv);
	145	return 0;
	146	}
	147
	148	static void __exit map_ram_exit(void)
	149	{
	150	unregister_mtd_chip_driver(&mapram_chipdrv);
	151	}
	152
	153	module_init(map_ram_init);
	154	module_exit(map_ram_exit);
	155
	156	MODULE_LICENSE("GPL");
	157	MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
	158	MODULE_DESCRIPTION("MTD chip driver for RAM chips");