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/*

 * Common code to handle map devices which are simple RAM

 * (C) 2000 Red Hat. GPL'd.

 * $Id: map_ram.c,v 1.1.1.1 2004-04-15 01:52:10 phoenix Exp $

 */

#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/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 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 = kmalloc(sizeof(*mtd), GFP_KERNEL);

        if (!mtd)

                return NULL;

        memset(mtd, 0, sizeof(*mtd));

        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->sync = mapram_nop;

        mtd->flags = MTD_CAP_RAM | MTD_VOLATILE;

        mtd->erasesize = PAGE_SIZE;

        while(mtd->size & (mtd->erasesize - 1))

                mtd->erasesize >>= 1;

        MOD_INC_USE_COUNT;

        return mtd;

}

static int mapram_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)

{

        struct map_info *map = (struct map_info *)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 = (struct map_info *)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 = (struct map_info *)mtd->priv;

        unsigned long i;

        for (i=0; i<instr->len; i++)

                map->write8(map, 0xFF, instr->addr + i);

        if (instr->callback)

                instr->callback(instr);

        return 0;

}

static void mapram_nop(struct mtd_info *mtd)

{

        /* Nothing to see here */

}

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");