pseries-rng.c

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/*
 * Copyright (C) 2010 Michael Neuling IBM Corporation
 *
 * Driver for the pseries hardware RNG for POWER7+ and above
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/module.h>
#include <linux/hw_random.h>
#include <asm/vio.h>

#define MODULE_NAME "pseries-rng"

static int pseries_rng_data_read(struct hwrng *rng, u32 *data)
{
    if (plpar_hcall(H_RANDOM, (unsigned long *)data) != H_SUCCESS) {
        printk(KERN_ERR "pseries rng hcall error\n");
        return 0;
    }
    return 8;
}

static unsigned long pseries_rng_get_desired_dma(struct vio_dev *vdev)
{
    return 0;
};

static struct hwrng pseries_rng = {
    .name       = MODULE_NAME,
    .data_read  = pseries_rng_data_read,
};

static int __init pseries_rng_probe(struct vio_dev *dev,
        const struct vio_device_id *id)
{
    return hwrng_register(&pseries_rng);
}

static int __exit pseries_rng_remove(struct vio_dev *dev)
{
    hwrng_unregister(&pseries_rng);
    return 0;
}

static struct vio_device_id pseries_rng_driver_ids[] = {
    { "ibm,random-v1", "ibm,random"},
    { "", "" }
};
MODULE_DEVICE_TABLE(vio, pseries_rng_driver_ids);

static struct vio_driver pseries_rng_driver = {
    .name = MODULE_NAME,
    .probe = pseries_rng_probe,
    .remove = pseries_rng_remove,
    .get_desired_dma = pseries_rng_get_desired_dma,
    .id_table = pseries_rng_driver_ids
};

static int __init rng_init(void)
{
    printk(KERN_INFO "Registering IBM pSeries RNG driver\n");
    return vio_register_driver(&pseries_rng_driver);
}

module_init(rng_init);

static void __exit rng_exit(void)
{
    vio_unregister_driver(&pseries_rng_driver);
}
module_exit(rng_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Michael Neuling <[email protected]>");
MODULE_DESCRIPTION("H/W RNG driver for IBM pSeries processors");