mtdram.c

Go to the documentation of this file.

/*
 * mtdram - a test mtd device
 * Author: Alexander Larsson <[email protected]>
 *
 * Copyright (c) 1999 Alexander Larsson <[email protected]>
 * Copyright (c) 2005 Joern Engel <[email protected]>
 *
 * This code is GPL
 *
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/mtdram.h>

static unsigned long total_size = CONFIG_MTDRAM_TOTAL_SIZE;
static unsigned long erase_size = CONFIG_MTDRAM_ERASE_SIZE;
#define MTDRAM_TOTAL_SIZE (total_size * 1024)
#define MTDRAM_ERASE_SIZE (erase_size * 1024)

#ifdef MODULE
module_param(total_size, ulong, 0);
MODULE_PARM_DESC(total_size, "Total device size in KiB");
module_param(erase_size, ulong, 0);
MODULE_PARM_DESC(erase_size, "Device erase block size in KiB");
#endif

// We could store these in the mtd structure, but we only support 1 device..
static struct mtd_info *mtd_info;

static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
{
    memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
    instr->state = MTD_ERASE_DONE;
    mtd_erase_callback(instr);
    return 0;
}

static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
        size_t *retlen, void **virt, resource_size_t *phys)
{
    *virt = mtd->priv + from;
    *retlen = len;
    return 0;
}

static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
{
    return 0;
}

/*
 * 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 ram_get_unmapped_area(struct mtd_info *mtd,
                       unsigned long len,
                       unsigned long offset,
                       unsigned long flags)
{
    return (unsigned long) mtd->priv + offset;
}

static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
        size_t *retlen, u_char *buf)
{
    memcpy(buf, mtd->priv + from, len);
    *retlen = len;
    return 0;
}

static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
        size_t *retlen, const u_char *buf)
{
    memcpy((char *)mtd->priv + to, buf, len);
    *retlen = len;
    return 0;
}

static void __exit cleanup_mtdram(void)
{
    if (mtd_info) {
        mtd_device_unregister(mtd_info);
        vfree(mtd_info->priv);
        kfree(mtd_info);
    }
}

int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
        unsigned long size, char *name)
{
    memset(mtd, 0, sizeof(*mtd));

    /* Setup the MTD structure */
    mtd->name = name;
    mtd->type = MTD_RAM;
    mtd->flags = MTD_CAP_RAM;
    mtd->size = size;
    mtd->writesize = 1;
    mtd->writebufsize = 64; /* Mimic CFI NOR flashes */
    mtd->erasesize = MTDRAM_ERASE_SIZE;
    mtd->priv = mapped_address;

    mtd->owner = THIS_MODULE;
    mtd->_erase = ram_erase;
    mtd->_point = ram_point;
    mtd->_unpoint = ram_unpoint;
    mtd->_get_unmapped_area = ram_get_unmapped_area;
    mtd->_read = ram_read;
    mtd->_write = ram_write;

    if (mtd_device_register(mtd, NULL, 0))
        return -EIO;

    return 0;
}

static int __init init_mtdram(void)
{
    void *addr;
    int err;

    if (!total_size)
        return -EINVAL;

    /* Allocate some memory */
    mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
    if (!mtd_info)
        return -ENOMEM;

    addr = vmalloc(MTDRAM_TOTAL_SIZE);
    if (!addr) {
        kfree(mtd_info);
        mtd_info = NULL;
        return -ENOMEM;
    }
    err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
    if (err) {
        vfree(addr);
        kfree(mtd_info);
        mtd_info = NULL;
        return err;
    }
    memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
    return err;
}

module_init(init_mtdram);
module_exit(cleanup_mtdram);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Alexander Larsson <[email protected]>");
MODULE_DESCRIPTION("Simulated MTD driver for testing");