bcm63xx-rng.c

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/*
 * Broadcom BCM63xx Random Number Generator support
 *
 * Copyright (C) 2011, Florian Fainelli <[email protected]>
 * Copyright (C) 2009, Broadcom Corporation
 *
 */
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
#include <linux/hw_random.h>

#include <bcm63xx_io.h>
#include <bcm63xx_regs.h>

struct bcm63xx_rng_priv {
    struct clk *clk;
    void __iomem *regs;
};

#define to_rng_priv(rng)    ((struct bcm63xx_rng_priv *)rng->priv)

static int bcm63xx_rng_init(struct hwrng *rng)
{
    struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
    u32 val;

    val = bcm_readl(priv->regs + RNG_CTRL);
    val |= RNG_EN;
    bcm_writel(val, priv->regs + RNG_CTRL);

    return 0;
}

static void bcm63xx_rng_cleanup(struct hwrng *rng)
{
    struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
    u32 val;

    val = bcm_readl(priv->regs + RNG_CTRL);
    val &= ~RNG_EN;
    bcm_writel(val, priv->regs + RNG_CTRL);
}

static int bcm63xx_rng_data_present(struct hwrng *rng, int wait)
{
    struct bcm63xx_rng_priv *priv = to_rng_priv(rng);

    return bcm_readl(priv->regs + RNG_STAT) & RNG_AVAIL_MASK;
}

static int bcm63xx_rng_data_read(struct hwrng *rng, u32 *data)
{
    struct bcm63xx_rng_priv *priv = to_rng_priv(rng);

    *data = bcm_readl(priv->regs + RNG_DATA);

    return 4;
}

static int __devinit bcm63xx_rng_probe(struct platform_device *pdev)
{
    struct resource *r;
    struct clk *clk;
    int ret;
    struct bcm63xx_rng_priv *priv;
    struct hwrng *rng;

    r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!r) {
        dev_err(&pdev->dev, "no iomem resource\n");
        ret = -ENXIO;
        goto out;
    }

    priv = kzalloc(sizeof(*priv), GFP_KERNEL);
    if (!priv) {
        dev_err(&pdev->dev, "no memory for private structure\n");
        ret = -ENOMEM;
        goto out;
    }

    rng = kzalloc(sizeof(*rng), GFP_KERNEL);
    if (!rng) {
        dev_err(&pdev->dev, "no memory for rng structure\n");
        ret = -ENOMEM;
        goto out_free_priv;
    }

    platform_set_drvdata(pdev, rng);
    rng->priv = (unsigned long)priv;
    rng->name = pdev->name;
    rng->init = bcm63xx_rng_init;
    rng->cleanup = bcm63xx_rng_cleanup;
    rng->data_present = bcm63xx_rng_data_present;
    rng->data_read = bcm63xx_rng_data_read;

    clk = clk_get(&pdev->dev, "ipsec");
    if (IS_ERR(clk)) {
        dev_err(&pdev->dev, "no clock for device\n");
        ret = PTR_ERR(clk);
        goto out_free_rng;
    }

    priv->clk = clk;

    if (!devm_request_mem_region(&pdev->dev, r->start,
                    resource_size(r), pdev->name)) {
        dev_err(&pdev->dev, "request mem failed");
        ret = -ENOMEM;
        goto out_free_rng;
    }

    priv->regs = devm_ioremap_nocache(&pdev->dev, r->start,
                    resource_size(r));
    if (!priv->regs) {
        dev_err(&pdev->dev, "ioremap failed");
        ret = -ENOMEM;
        goto out_free_rng;
    }

    clk_enable(clk);

    ret = hwrng_register(rng);
    if (ret) {
        dev_err(&pdev->dev, "failed to register rng device\n");
        goto out_clk_disable;
    }

    dev_info(&pdev->dev, "registered RNG driver\n");

    return 0;

out_clk_disable:
    clk_disable(clk);
out_free_rng:
    platform_set_drvdata(pdev, NULL);
    kfree(rng);
out_free_priv:
    kfree(priv);
out:
    return ret;
}

static int __devexit bcm63xx_rng_remove(struct platform_device *pdev)
{
    struct hwrng *rng = platform_get_drvdata(pdev);
    struct bcm63xx_rng_priv *priv = to_rng_priv(rng);

    hwrng_unregister(rng);
    clk_disable(priv->clk);
    kfree(priv);
    kfree(rng);
    platform_set_drvdata(pdev, NULL);

    return 0;
}

static struct platform_driver bcm63xx_rng_driver = {
    .probe      = bcm63xx_rng_probe,
    .remove     = __devexit_p(bcm63xx_rng_remove),
    .driver     = {
        .name   = "bcm63xx-rng",
        .owner  = THIS_MODULE,
    },
};

module_platform_driver(bcm63xx_rng_driver);

MODULE_AUTHOR("Florian Fainelli <[email protected]>");
MODULE_DESCRIPTION("Broadcom BCM63xx RNG driver");
MODULE_LICENSE("GPL");