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/*
* RNG driver for Moschip MCS814x SoC
*
* Copyright 2012 (C), Florian Fainelli <florian@openwrt.org>
*
* 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/slab.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/platform_device.h>
#include <linux/hw_random.h>
#include <linux/io.h>
#include <linux/of.h>
#define STAT 0x00
#define RND 0x04
struct mcs814x_rng_priv {
void __iomem *regs;
};
static int mcs814x_rng_data_read(struct hwrng *rng, u32 *buffer)
{
struct mcs814x_rng_priv *priv = (struct mcs814x_rng_priv *)rng->priv;
*buffer = __raw_readl(priv->regs + RND);
return 4;
}
static int mcs814x_rng_probe(struct platform_device *pdev)
{
struct resource *res;
struct mcs814x_rng_priv *priv;
struct hwrng *rng;
int ret;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENODEV;
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv) {
ret = -ENOMEM;
goto out;
}
rng = kzalloc(sizeof(*rng), GFP_KERNEL);
if (!rng) {
ret = -ENOMEM;
goto out_priv;
}
platform_set_drvdata(pdev, rng);
rng->priv = (unsigned long)priv;
rng->name = pdev->name;
rng->data_read = mcs814x_rng_data_read;
if (!devm_request_mem_region(&pdev->dev,
res->start, resource_size(res),
pdev->name)) {
ret = -EBUSY;
goto out_rng;
}
priv->regs = devm_ioremap(&pdev->dev, res->start, resource_size(res));
if (!priv->regs) {
ret = -ENOMEM;
goto out_rng;
}
ret = hwrng_register(rng);
if (ret) {
dev_err(&pdev->dev, "failed to register hwrng driver\n");
goto out;
}
dev_info(&pdev->dev, "registered\n");
return ret;
out_rng:
platform_set_drvdata(pdev, NULL);
kfree(rng);
out_priv:
kfree(priv);
out:
return ret;
}
static int mcs814x_rng_remove(struct platform_device *pdev)
{
struct hwrng *rng = platform_get_drvdata(pdev);
struct mcs814x_rng_priv *priv = (struct mcs814x_rng_priv *)rng->priv;
hwrng_unregister(rng);
kfree(priv);
kfree(rng);
platform_set_drvdata(pdev, NULL);
return 0;
}
static const struct of_device_id mcs814x_rng_ids[] = {
{ .compatible = "moschip,mcs814x-rng", },
{ /* sentinel */ },
};
static struct platform_driver mcs814x_rng_driver = {
.driver = {
.name = "mcs814x-rng",
.owner = THIS_MODULE,
.of_match_table = mcs814x_rng_ids,
},
.probe = mcs814x_rng_probe,
.remove = __devexit_p(mcs814x_rng_remove),
};
module_platform_driver(mcs814x_rng_driver);
MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
MODULE_DESCRIPTION("H/W Random Number Generator (RNG) for Moschip MCS814x");
MODULE_LICENSE("GPL");
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