[linux.git] / drivers / mtd / chips / map_absent.c

/*
 * Common code to handle absent "placeholder" devices
 * Copyright 2001 Resilience Corporation <[email protected]>
 *
 * This map driver is used to allocate "placeholder" MTD
 * devices on systems that have socketed/removable media.
 * Use of this driver as a fallback preserves the expected
 * registration of MTD device nodes regardless of probe outcome.
 * A usage example is as follows:
 *
 *		my_dev[i] = do_map_probe("cfi", &my_map[i]);
 *		if(NULL == my_dev[i]) {
 *			my_dev[i] = do_map_probe("map_absent", &my_map[i]);
 *		}
 *
 * Any device 'probed' with this driver will return -ENODEV
 * upon open.
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.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 map_absent_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *);
static int map_absent_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
static int map_absent_erase (struct mtd_info *, struct erase_info *);
static void map_absent_sync (struct mtd_info *);
static struct mtd_info *map_absent_probe(struct map_info *map);
static void map_absent_destroy (struct mtd_info *);


static struct mtd_chip_driver map_absent_chipdrv = {
	.probe		= map_absent_probe,
	.destroy	= map_absent_destroy,
	.name		= "map_absent",
	.module		= THIS_MODULE
};

static struct mtd_info *map_absent_probe(struct map_info *map)
{
	struct mtd_info *mtd;

	mtd = kzalloc(sizeof(*mtd), GFP_KERNEL);
	if (!mtd) {
		return NULL;
	}

	map->fldrv 	= &map_absent_chipdrv;
	mtd->priv 	= map;
	mtd->name 	= map->name;
	mtd->type 	= MTD_ABSENT;
	mtd->size 	= map->size;
	mtd->_erase 	= map_absent_erase;
	mtd->_read 	= map_absent_read;
	mtd->_write 	= map_absent_write;
	mtd->_sync 	= map_absent_sync;
	mtd->flags 	= 0;
	mtd->erasesize  = PAGE_SIZE;
	mtd->writesize  = 1;

	__module_get(THIS_MODULE);
	return mtd;
}


static int map_absent_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
{
	return -ENODEV;
}

static int map_absent_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf)
{
	return -ENODEV;
}

static int map_absent_erase(struct mtd_info *mtd, struct erase_info *instr)
{
	return -ENODEV;
}

static void map_absent_sync(struct mtd_info *mtd)
{
	/* nop */
}

static void map_absent_destroy(struct mtd_info *mtd)
{
	/* nop */
}

static int __init map_absent_init(void)
{
	register_mtd_chip_driver(&map_absent_chipdrv);
	return 0;
}

static void __exit map_absent_exit(void)
{
	unregister_mtd_chip_driver(&map_absent_chipdrv);
}

module_init(map_absent_init);
module_exit(map_absent_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Resilience Corporation - Eric Brower <[email protected]>");
MODULE_DESCRIPTION("Placeholder MTD chip driver for 'absent' chips");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Common code to handle absent "placeholder" devices
	3	* Copyright 2001 Resilience Corporation <[email protected]>
1da177e4 LT	4	*
1da177e4 LT	5	* This map driver is used to allocate "placeholder" MTD
1f948b43 TG	6	* devices on systems that have socketed/removable media.
1f948b43 TG	7	* Use of this driver as a fallback preserves the expected
1da177e4 LT	8	* registration of MTD device nodes regardless of probe outcome.
	9	* A usage example is as follows:
	10	*
	11	* my_dev[i] = do_map_probe("cfi", &my_map[i]);
	12	* if(NULL == my_dev[i]) {
	13	* my_dev[i] = do_map_probe("map_absent", &my_map[i]);
	14	* }
	15	*
	16	* Any device 'probed' with this driver will return -ENODEV
	17	* upon open.
	18	*/
	19
	20	#include <linux/module.h>
	21	#include <linux/types.h>
	22	#include <linux/kernel.h>
	23	#include <linux/errno.h>
	24	#include <linux/slab.h>
	25	#include <linux/init.h>
	26	#include <linux/mtd/mtd.h>
	27	#include <linux/mtd/map.h>
1da177e4 LT	28
	29	static int map_absent_read (struct mtd_info , loff_t, size_t, size_t , u_char *);
	30	static int map_absent_write (struct mtd_info , loff_t, size_t, size_t , const u_char *);
	31	static int map_absent_erase (struct mtd_info , struct erase_info );
	32	static void map_absent_sync (struct mtd_info *);
	33	static struct mtd_info map_absent_probe(struct map_info map);
	34	static void map_absent_destroy (struct mtd_info *);
	35
	36
	37	static struct mtd_chip_driver map_absent_chipdrv = {
	38	.probe = map_absent_probe,
	39	.destroy = map_absent_destroy,
	40	.name = "map_absent",
	41	.module = THIS_MODULE
	42	};
	43
	44	static struct mtd_info map_absent_probe(struct map_info map)
	45	{
	46	struct mtd_info *mtd;
	47
95b93a0c	48	mtd = kzalloc(sizeof(*mtd), GFP_KERNEL);
1da177e4 LT	49	if (!mtd) {
	50	return NULL;
	51	}
	52
1da177e4 LT	53	map->fldrv = &map_absent_chipdrv;
	54	mtd->priv = map;
	55	mtd->name = map->name;
	56	mtd->type = MTD_ABSENT;
	57	mtd->size = map->size;
3c3c10bb AB	58	mtd->_erase = map_absent_erase;
	59	mtd->_read = map_absent_read;
	60	mtd->_write = map_absent_write;
	61	mtd->_sync = map_absent_sync;
1da177e4	62	mtd->flags = 0;
17ffc7ba AB	63	mtd->erasesize = PAGE_SIZE;
17ffc7ba AB	64	mtd->writesize = 1;
1da177e4 LT	65
	66	__module_get(THIS_MODULE);
	67	return mtd;
	68	}
	69
	70
	71	static int map_absent_read(struct mtd_info mtd, loff_t from, size_t len, size_t retlen, u_char *buf)
	72	{
1da177e4 LT	73	return -ENODEV;
	74	}
	75
	76	static int map_absent_write(struct mtd_info mtd, loff_t to, size_t len, size_t retlen, const u_char *buf)
	77	{
1f948b43	78	return -ENODEV;
1da177e4 LT	79	}
	80
	81	static int map_absent_erase(struct mtd_info mtd, struct erase_info instr)
	82	{
	83	return -ENODEV;
	84	}
	85
	86	static void map_absent_sync(struct mtd_info *mtd)
	87	{
	88	/* nop */
	89	}
	90
	91	static void map_absent_destroy(struct mtd_info *mtd)
	92	{
	93	/* nop */
	94	}
	95
	96	static int __init map_absent_init(void)
	97	{
	98	register_mtd_chip_driver(&map_absent_chipdrv);
	99	return 0;
	100	}
	101
	102	static void __exit map_absent_exit(void)
	103	{
	104	unregister_mtd_chip_driver(&map_absent_chipdrv);
	105	}
	106
	107	module_init(map_absent_init);
	108	module_exit(map_absent_exit);
	109
	110	MODULE_LICENSE("GPL");
	111	MODULE_AUTHOR("Resilience Corporation - Eric Brower <[email protected]>");
	112	MODULE_DESCRIPTION("Placeholder MTD chip driver for 'absent' chips");