ixp4xx-rng.c

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/*
 * drivers/char/hw_random/ixp4xx-rng.c
 *
 * RNG driver for Intel IXP4xx family of NPUs
 *
 * Author: Deepak Saxena <[email protected]>
 *
 * Copyright 2005 (c) MontaVista Software, Inc.
 *
 * Fixes by Michael Buesch
 *
 * This file is licensed under  the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/hw_random.h>

#include <asm/io.h>
#include <mach/hardware.h>


static int ixp4xx_rng_data_read(struct hwrng *rng, u32 *buffer)
{
    void __iomem * rng_base = (void __iomem *)rng->priv;

    *buffer = __raw_readl(rng_base);

    return 4;
}

static struct hwrng ixp4xx_rng_ops = {
    .name       = "ixp4xx",
    .data_read  = ixp4xx_rng_data_read,
};

static int __init ixp4xx_rng_init(void)
{
    void __iomem * rng_base;
    int err;

    if (!cpu_is_ixp46x()) /* includes IXP455 */
        return -ENOSYS;

    rng_base = ioremap(0x70002100, 4);
    if (!rng_base)
        return -ENOMEM;
    ixp4xx_rng_ops.priv = (unsigned long)rng_base;
    err = hwrng_register(&ixp4xx_rng_ops);
    if (err)
        iounmap(rng_base);

    return err;
}

static void __exit ixp4xx_rng_exit(void)
{
    void __iomem * rng_base = (void __iomem *)ixp4xx_rng_ops.priv;

    hwrng_unregister(&ixp4xx_rng_ops);
    iounmap(rng_base);
}

module_init(ixp4xx_rng_init);
module_exit(ixp4xx_rng_exit);

MODULE_AUTHOR("Deepak Saxena <[email protected]>");
MODULE_DESCRIPTION("H/W Pseudo-Random Number Generator (RNG) driver for IXP45x/46x");
MODULE_LICENSE("GPL");