hw_random: add driver for atmel true hardware random number generator (677d3e2f) · Commits · e / devices / android_kernel_xiaomi_markw

drivers/char/hw_random/Kconfig

+13 −0

Original line number	Diff line number	Diff line
		@@ -60,6 +60,19 @@ config HW_RANDOM_AMD

		If unsure, say Y.

		config HW_RANDOM_ATMEL
		tristate "Atmel Random Number Generator support"
		depends on HW_RANDOM && ARCH_AT91SAM9G45
		default HW_RANDOM
		---help---
		This driver provides kernel-side support for the Random Number
		Generator hardware found on Atmel AT91 devices.

		To compile this driver as a module, choose M here: the
		module will be called atmel-rng.

		If unsure, say Y.

		config HW_RANDOM_GEODE
		tristate "AMD Geode HW Random Number Generator support"
		depends on HW_RANDOM && X86_32 && PCI

drivers/char/hw_random/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -7,6 +7,7 @@ rng-core-y := core.o
		obj-$(CONFIG_HW_RANDOM_TIMERIOMEM) += timeriomem-rng.o
		obj-$(CONFIG_HW_RANDOM_INTEL) += intel-rng.o
		obj-$(CONFIG_HW_RANDOM_AMD) += amd-rng.o
		obj-$(CONFIG_HW_RANDOM_ATMEL) += atmel-rng.o
		obj-$(CONFIG_HW_RANDOM_GEODE) += geode-rng.o
		obj-$(CONFIG_HW_RANDOM_N2RNG) += n2-rng.o
		n2-rng-y := n2-drv.o n2-asm.o

drivers/char/hw_random/atmel-rng.c

0 → 100644

+158 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (c) 2011 Peter Korsgaard <jacmet@sunsite.dk>
		*
		* 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/module.h>
		#include <linux/slab.h>
		#include <linux/err.h>
		#include <linux/clk.h>
		#include <linux/io.h>
		#include <linux/hw_random.h>
		#include <linux/platform_device.h>

		#define TRNG_CR 0x00
		#define TRNG_ISR 0x1c
		#define TRNG_ODATA 0x50

		#define TRNG_KEY 0x524e4700 /* RNG */

		struct atmel_trng {
		struct clk *clk;
		void __iomem *base;
		struct hwrng rng;
		};

		static int atmel_trng_read(struct hwrng rng, void buf, size_t max,
		bool wait)
		{
		struct atmel_trng *trng = container_of(rng, struct atmel_trng, rng);
		u32 *data = buf;

		/* data ready? */
		if (readl(trng->base + TRNG_ODATA) & 1) {
		*data = readl(trng->base + TRNG_ODATA);
		return 4;
		} else
		return 0;
		}

		static int atmel_trng_probe(struct platform_device *pdev)
		{
		struct atmel_trng *trng;
		struct resource *res;
		int ret;

		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
		if (!res)
		return -EINVAL;

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

		if (!devm_request_mem_region(&pdev->dev, res->start,
		resource_size(res), pdev->name))
		return -EBUSY;

		trng->base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
		if (!trng->base)
		return -EBUSY;

		trng->clk = clk_get(&pdev->dev, NULL);
		if (IS_ERR(trng->clk))
		return PTR_ERR(trng->clk);

		ret = clk_enable(trng->clk);
		if (ret)
		goto err_enable;

		writel(TRNG_KEY \| 1, trng->base + TRNG_CR);
		trng->rng.name = pdev->name;
		trng->rng.read = atmel_trng_read;

		ret = hwrng_register(&trng->rng);
		if (ret)
		goto err_register;

		platform_set_drvdata(pdev, trng);

		return 0;

		err_register:
		clk_disable(trng->clk);
		err_enable:
		clk_put(trng->clk);

		return ret;
		}

		static int __devexit atmel_trng_remove(struct platform_device *pdev)
		{
		struct atmel_trng *trng = platform_get_drvdata(pdev);

		hwrng_unregister(&trng->rng);

		writel(TRNG_KEY, trng->base + TRNG_CR);
		clk_disable(trng->clk);
		clk_put(trng->clk);

		platform_set_drvdata(pdev, NULL);

		return 0;
		}

		#ifdef CONFIG_PM
		static int atmel_trng_suspend(struct device *dev)
		{
		struct atmel_trng *trng = dev_get_drvdata(dev);

		clk_disable(trng->clk);

		return 0;
		}

		static int atmel_trng_resume(struct device *dev)
		{
		struct atmel_trng *trng = dev_get_drvdata(dev);

		return clk_enable(trng->clk);
		}

		static const struct dev_pm_ops atmel_trng_pm_ops = {
		.suspend = atmel_trng_suspend,
		.resume = atmel_trng_resume,
		};
		#endif /* CONFIG_PM */

		static struct platform_driver atmel_trng_driver = {
		.probe = atmel_trng_probe,
		.remove = __devexit_p(atmel_trng_remove),
		.driver = {
		.name = "atmel-trng",
		.owner = THIS_MODULE,
		#ifdef CONFIG_PM
		.pm = &atmel_trng_pm_ops,
		#endif /* CONFIG_PM */
		},
		};

		static int __init atmel_trng_init(void)
		{
		return platform_driver_register(&atmel_trng_driver);
		}
		module_init(atmel_trng_init);

		static void __exit atmel_trng_exit(void)
		{
		platform_driver_unregister(&atmel_trng_driver);
		}
		module_exit(atmel_trng_exit);

		MODULE_LICENSE("GPL");
		MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
		MODULE_DESCRIPTION("Atmel true random number generator driver");