octeon-rng.c

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/*
 * Hardware Random Number Generator support for Cavium Networks
 * Octeon processor family.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2009 Cavium Networks
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/device.h>
#include <linux/hw_random.h>
#include <linux/io.h>
#include <linux/gfp.h>

#include <asm/octeon/octeon.h>
#include <asm/octeon/cvmx-rnm-defs.h>

struct octeon_rng {
    struct hwrng ops;
    void __iomem *control_status;
    void __iomem *result;
};

static int octeon_rng_init(struct hwrng *rng)
{
    union cvmx_rnm_ctl_status ctl;
    struct octeon_rng *p = container_of(rng, struct octeon_rng, ops);

    ctl.u64 = 0;
    ctl.s.ent_en = 1; /* Enable the entropy source.  */
    ctl.s.rng_en = 1; /* Enable the RNG hardware.  */
    cvmx_write_csr((u64)p->control_status, ctl.u64);
    return 0;
}

static void octeon_rng_cleanup(struct hwrng *rng)
{
    union cvmx_rnm_ctl_status ctl;
    struct octeon_rng *p = container_of(rng, struct octeon_rng, ops);

    ctl.u64 = 0;
    /* Disable everything.  */
    cvmx_write_csr((u64)p->control_status, ctl.u64);
}

static int octeon_rng_data_read(struct hwrng *rng, u32 *data)
{
    struct octeon_rng *p = container_of(rng, struct octeon_rng, ops);

    *data = cvmx_read64_uint32((u64)p->result);
    return sizeof(u32);
}

static int __devinit octeon_rng_probe(struct platform_device *pdev)
{
    struct resource *res_ports;
    struct resource *res_result;
    struct octeon_rng *rng;
    int ret;
    struct hwrng ops = {
        .name = "octeon",
        .init = octeon_rng_init,
        .cleanup = octeon_rng_cleanup,
        .data_read = octeon_rng_data_read
    };

    rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
    if (!rng)
        return -ENOMEM;

    res_ports = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!res_ports)
        return -ENOENT;

    res_result = platform_get_resource(pdev, IORESOURCE_MEM, 1);
    if (!res_result)
        return -ENOENT;


    rng->control_status = devm_ioremap_nocache(&pdev->dev,
                           res_ports->start,
                           sizeof(u64));
    if (!rng->control_status)
        return -ENOENT;

    rng->result = devm_ioremap_nocache(&pdev->dev,
                       res_result->start,
                       sizeof(u64));
    if (!rng->result)
        return -ENOENT;

    rng->ops = ops;

    dev_set_drvdata(&pdev->dev, &rng->ops);
    ret = hwrng_register(&rng->ops);
    if (ret)
        return -ENOENT;

    dev_info(&pdev->dev, "Octeon Random Number Generator\n");

    return 0;
}

static int __exit octeon_rng_remove(struct platform_device *pdev)
{
    struct hwrng *rng = dev_get_drvdata(&pdev->dev);

    hwrng_unregister(rng);

    return 0;
}

static struct platform_driver octeon_rng_driver = {
    .driver = {
        .name       = "octeon_rng",
        .owner      = THIS_MODULE,
    },
    .probe      = octeon_rng_probe,
    .remove     = __exit_p(octeon_rng_remove),
};

module_platform_driver(octeon_rng_driver);

MODULE_AUTHOR("David Daney");
MODULE_LICENSE("GPL");