linux-imx

/*

 * 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

 */

​

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

​

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/hw_random.h>

#include <asm/vio.h>

​

​

static int pseries_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)

{

    u64 buffer[PLPAR_HCALL_BUFSIZE];

    int rc;

​

    rc = plpar_hcall(H_RANDOM, (unsigned long *)buffer);

    if (rc != H_SUCCESS) {

        pr_err_ratelimited("H_RANDOM call failed %d\n", rc);

        return -EIO;

    }

    memcpy(data, buffer, 8);

​

    /* The hypervisor interface returns 64 bits */

    return 8;

}

​

/**

 * pseries_rng_get_desired_dma - Return desired DMA allocate for CMO operations

 *

 * This is a required function for a driver to operate in a CMO environment

 * but this device does not make use of DMA allocations, return 0.

 *

 * Return value:

 *  Number of bytes of IO data the driver will need to perform well -> 0

 */

static unsigned long pseries_rng_get_desired_dma(struct vio_dev *vdev)

{

    return 0;

};

​

static struct hwrng pseries_rng = {

    .name       = KBUILD_MODNAME,

    .read       = pseries_rng_read,

};

​

static int pseries_rng_probe(struct vio_dev *dev,