hwrng: mtk - Add driver for hardware random generator on MT7623 SoC (7701d1ff) · Commits · e / devices / android_kernel_oneplus_sm7250

drivers/char/hw_random/Kconfig

+14 −0

Original line number	Diff line number	Diff line
		@@ -409,6 +409,20 @@ config HW_RANDOM_CAVIUM

		If unsure, say Y.

		config HW_RANDOM_MTK
		tristate "Mediatek Random Number Generator support"
		depends on HW_RANDOM
		depends on ARCH_MEDIATEK \|\| COMPILE_TEST
		default y
		---help---
		This driver provides kernel-side support for the Random Number
		Generator hardware found on Mediatek SoCs.

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

		If unsure, say Y.

		endif # HW_RANDOM

		config UML_RANDOM

drivers/char/hw_random/Makefile

+1 −0

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		@@ -35,3 +35,4 @@ obj-$(CONFIG_HW_RANDOM_STM32) += stm32-rng.o
		obj-$(CONFIG_HW_RANDOM_PIC32) += pic32-rng.o
		obj-$(CONFIG_HW_RANDOM_MESON) += meson-rng.o
		obj-$(CONFIG_HW_RANDOM_CAVIUM) += cavium-rng.o cavium-rng-vf.o
		obj-$(CONFIG_HW_RANDOM_MTK) += mtk-rng.o

drivers/char/hw_random/mtk-rng.c

0 → 100644

+168 −0

Original line number	Diff line number	Diff line
		/*
		* Driver for Mediatek Hardware Random Number Generator
		*
		* Copyright (C) 2017 Sean Wang <sean.wang@mediatek.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; either version 2 of
		* the License, or (at your option) any later version.
		*
		* 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.
		*/
		#define MTK_RNG_DEV KBUILD_MODNAME

		#include <linux/clk.h>
		#include <linux/delay.h>
		#include <linux/err.h>
		#include <linux/hw_random.h>
		#include <linux/io.h>
		#include <linux/iopoll.h>
		#include <linux/kernel.h>
		#include <linux/module.h>
		#include <linux/of.h>
		#include <linux/platform_device.h>

		#define USEC_POLL 2
		#define TIMEOUT_POLL 20

		#define RNG_CTRL 0x00
		#define RNG_EN BIT(0)
		#define RNG_READY BIT(31)

		#define RNG_DATA 0x08

		#define to_mtk_rng(p) container_of(p, struct mtk_rng, rng)

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

		static int mtk_rng_init(struct hwrng *rng)
		{
		struct mtk_rng *priv = to_mtk_rng(rng);
		u32 val;
		int err;

		err = clk_prepare_enable(priv->clk);
		if (err)
		return err;

		val = readl(priv->base + RNG_CTRL);
		val \|= RNG_EN;
		writel(val, priv->base + RNG_CTRL);

		return 0;
		}

		static void mtk_rng_cleanup(struct hwrng *rng)
		{
		struct mtk_rng *priv = to_mtk_rng(rng);
		u32 val;

		val = readl(priv->base + RNG_CTRL);
		val &= ~RNG_EN;
		writel(val, priv->base + RNG_CTRL);

		clk_disable_unprepare(priv->clk);
		}

		static bool mtk_rng_wait_ready(struct hwrng *rng, bool wait)
		{
		struct mtk_rng *priv = to_mtk_rng(rng);
		int ready;

		ready = readl(priv->base + RNG_CTRL) & RNG_READY;
		if (!ready && wait)
		readl_poll_timeout_atomic(priv->base + RNG_CTRL, ready,
		ready & RNG_READY, USEC_POLL,
		TIMEOUT_POLL);
		return !!ready;
		}

		static int mtk_rng_read(struct hwrng rng, void buf, size_t max, bool wait)
		{
		struct mtk_rng *priv = to_mtk_rng(rng);
		int retval = 0;

		while (max >= sizeof(u32)) {
		if (!mtk_rng_wait_ready(rng, wait))
		break;

		(u32 )buf = readl(priv->base + RNG_DATA);
		retval += sizeof(u32);
		buf += sizeof(u32);
		max -= sizeof(u32);
		}

		return retval \|\| !wait ? retval : -EIO;
		}

		static int mtk_rng_probe(struct platform_device *pdev)
		{
		struct resource *res;
		int ret;
		struct mtk_rng *priv;

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

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

		priv->rng.name = pdev->name;
		priv->rng.init = mtk_rng_init;
		priv->rng.cleanup = mtk_rng_cleanup;
		priv->rng.read = mtk_rng_read;

		priv->clk = devm_clk_get(&pdev->dev, "rng");
		if (IS_ERR(priv->clk)) {
		ret = PTR_ERR(priv->clk);
		dev_err(&pdev->dev, "no clock for device: %d\n", ret);
		return ret;
		}

		priv->base = devm_ioremap_resource(&pdev->dev, res);
		if (IS_ERR(priv->base))
		return PTR_ERR(priv->base);

		ret = devm_hwrng_register(&pdev->dev, &priv->rng);
		if (ret) {
		dev_err(&pdev->dev, "failed to register rng device: %d\n",
		ret);
		return ret;
		}

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

		return 0;
		}

		static const struct of_device_id mtk_rng_match[] = {
		{ .compatible = "mediatek,mt7623-rng" },
		{},
		};
		MODULE_DEVICE_TABLE(of, mtk_rng_match);

		static struct platform_driver mtk_rng_driver = {
		.probe = mtk_rng_probe,
		.driver = {
		.name = MTK_RNG_DEV,
		.of_match_table = mtk_rng_match,
		},
		};

		module_platform_driver(mtk_rng_driver);

		MODULE_DESCRIPTION("Mediatek Random Number Generator Driver");
		MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
		MODULE_LICENSE("GPL");