hwrng: exynos - Add support for Exynos random number generator (b329669e) · Commits · e / devices / android_kernel_oneplus_sm7250

drivers/char/hw_random/Kconfig

+12 −0

Original line number	Diff line number	Diff line
		@@ -263,3 +263,15 @@ config HW_RANDOM_PSERIES
		module will be called pseries-rng.

		If unsure, say Y.

		config HW_RANDOM_EXYNOS
		tristate "EXYNOS HW random number generator support"
		depends on HW_RANDOM && HAS_IOMEM && HAVE_CLK
		---help---
		This driver provides kernel-side support for the Random Number
		Generator hardware found on EXYNOS SOCs.

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

		If unsure, say Y.

drivers/char/hw_random/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -23,3 +23,4 @@ obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o
		obj-$(CONFIG_HW_RANDOM_PICOXCELL) += picoxcell-rng.o
		obj-$(CONFIG_HW_RANDOM_PPC4XX) += ppc4xx-rng.o
		obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o
		obj-$(CONFIG_HW_RANDOM_EXYNOS) += exynos-rng.o

drivers/char/hw_random/exynos-rng.c

0 → 100644

+182 −0

Original line number	Diff line number	Diff line
		/*
		* exynos-rng.c - Random Number Generator driver for the exynos
		*
		* Copyright (C) 2012 Samsung Electronics
		* Jonghwa Lee <jonghwa3.lee@smasung.com>
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License 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
		*
		*/

		#include <linux/hw_random.h>
		#include <linux/kernel.h>
		#include <linux/module.h>
		#include <linux/init.h>
		#include <linux/io.h>
		#include <linux/platform_device.h>
		#include <linux/clk.h>
		#include <linux/pm_runtime.h>
		#include <linux/err.h>

		#define EXYNOS_PRNG_STATUS_OFFSET 0x10
		#define EXYNOS_PRNG_SEED_OFFSET 0x140
		#define EXYNOS_PRNG_OUT1_OFFSET 0x160
		#define SEED_SETTING_DONE BIT(1)
		#define PRNG_START 0x18
		#define PRNG_DONE BIT(5)
		#define EXYNOS_AUTOSUSPEND_DELAY 100

		struct exynos_rng {
		struct device *dev;
		struct hwrng rng;
		void __iomem *mem;
		struct clk *clk;
		};

		static u32 exynos_rng_readl(struct exynos_rng *rng, u32 offset)
		{
		return __raw_readl(rng->mem + offset);
		}

		static void exynos_rng_writel(struct exynos_rng *rng, u32 val, u32 offset)
		{
		__raw_writel(val, rng->mem + offset);
		}

		static int exynos_init(struct hwrng *rng)
		{
		struct exynos_rng *exynos_rng = container_of(rng,
		struct exynos_rng, rng);
		int i;
		int ret = 0;

		pm_runtime_get_sync(exynos_rng->dev);

		for (i = 0 ; i < 5 ; i++)
		exynos_rng_writel(exynos_rng, jiffies,
		EXYNOS_PRNG_SEED_OFFSET + 4*i);

		if (!(exynos_rng_readl(exynos_rng, EXYNOS_PRNG_STATUS_OFFSET)
		& SEED_SETTING_DONE))
		ret = -EIO;

		pm_runtime_put_noidle(exynos_rng->dev);

		return ret;
		}

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

		pm_runtime_get_sync(exynos_rng->dev);

		exynos_rng_writel(exynos_rng, PRNG_START, 0);

		while (!(exynos_rng_readl(exynos_rng,
		EXYNOS_PRNG_STATUS_OFFSET) & PRNG_DONE))
		cpu_relax();

		exynos_rng_writel(exynos_rng, PRNG_DONE, EXYNOS_PRNG_STATUS_OFFSET);

		*data = exynos_rng_readl(exynos_rng, EXYNOS_PRNG_OUT1_OFFSET);

		pm_runtime_mark_last_busy(exynos_rng->dev);
		pm_runtime_autosuspend(exynos_rng->dev);

		return 4;
		}

		static int __devinit exynos_rng_probe(struct platform_device *pdev)
		{
		struct exynos_rng *exynos_rng;

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

		exynos_rng->dev = &pdev->dev;
		exynos_rng->rng.name = "exynos";
		exynos_rng->rng.init = exynos_init;
		exynos_rng->rng.read = exynos_read;
		exynos_rng->clk = devm_clk_get(&pdev->dev, "secss");
		if (IS_ERR(exynos_rng->clk)) {
		dev_err(&pdev->dev, "Couldn't get clock.\n");
		return -ENOENT;
		}

		exynos_rng->mem = devm_request_and_ioremap(&pdev->dev,
		platform_get_resource(pdev, IORESOURCE_MEM, 0));
		if (!exynos_rng->mem)
		return -EBUSY;

		platform_set_drvdata(pdev, exynos_rng);

		pm_runtime_set_autosuspend_delay(&pdev->dev, EXYNOS_AUTOSUSPEND_DELAY);
		pm_runtime_use_autosuspend(&pdev->dev);
		pm_runtime_enable(&pdev->dev);

		return hwrng_register(&exynos_rng->rng);
		}

		static int __devexit exynos_rng_remove(struct platform_device *pdev)
		{
		struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);

		hwrng_unregister(&exynos_rng->rng);

		return 0;
		}

		static int exynos_rng_runtime_suspend(struct device *dev)
		{
		struct platform_device *pdev = to_platform_device(dev);
		struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);

		clk_disable_unprepare(exynos_rng->clk);

		return 0;
		}

		static int exynos_rng_runtime_resume(struct device *dev)
		{
		struct platform_device *pdev = to_platform_device(dev);
		struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);

		return clk_prepare_enable(exynos_rng->clk);
		}


		UNIVERSAL_DEV_PM_OPS(exynos_rng_pm_ops, exynos_rng_runtime_suspend,
		exynos_rng_runtime_resume, NULL);

		static struct platform_driver exynos_rng_driver = {
		.driver = {
		.name = "exynos-rng",
		.owner = THIS_MODULE,
		.pm = &exynos_rng_pm_ops,
		},
		.probe = exynos_rng_probe,
		.remove = __devexit_p(exynos_rng_remove),
		};

		module_platform_driver(exynos_rng_driver);

		MODULE_DESCRIPTION("EXYNOS 4 H/W Random Number Generator driver");
		MODULE_AUTHOR("Jonghwa Lee <jonghwa3.lee@samsung.com>");
		MODULE_LICENSE("GPL");