hwrng: OMAP3 ROM Random Number Generator support (1c6b7c21) · Commits · e / devices / android_kernel_xiaomi_markw

drivers/char/hw_random/Kconfig

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		@@ -165,6 +165,19 @@ config HW_RANDOM_OMAP

		If unsure, say Y.

		config HW_RANDOM_OMAP3_ROM
		tristate "OMAP3 ROM Random Number Generator support"
		depends on HW_RANDOM && ARCH_OMAP3
		default HW_RANDOM
		---help---
		This driver provides kernel-side support for the Random Number
		Generator hardware found on OMAP34xx processors.

		To compile this driver as a module, choose M here: the
		module will be called omap3-rom-rng.

		If unsure, say Y.

		config HW_RANDOM_OCTEON
		tristate "Octeon Random Number Generator support"
		depends on HW_RANDOM && CAVIUM_OCTEON_SOC

drivers/char/hw_random/Makefile

+1 −0

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		@@ -15,6 +15,7 @@ n2-rng-y := n2-drv.o n2-asm.o
		obj-$(CONFIG_HW_RANDOM_VIA) += via-rng.o
		obj-$(CONFIG_HW_RANDOM_IXP4XX) += ixp4xx-rng.o
		obj-$(CONFIG_HW_RANDOM_OMAP) += omap-rng.o
		obj-$(CONFIG_HW_RANDOM_OMAP3_ROM) += omap3-rom-rng.o
		obj-$(CONFIG_HW_RANDOM_PASEMI) += pasemi-rng.o
		obj-$(CONFIG_HW_RANDOM_VIRTIO) += virtio-rng.o
		obj-$(CONFIG_HW_RANDOM_TX4939) += tx4939-rng.o

drivers/char/hw_random/omap3-rom-rng.c

0 → 100644

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		/*
		* omap3-rom-rng.c - RNG driver for TI OMAP3 CPU family
		*
		* Copyright (C) 2009 Nokia Corporation
		* Author: Juha Yrjola <juha.yrjola@solidboot.com>
		*
		* Copyright (C) 2013 Pali Rohár <pali.rohar@gmail.com>
		*
		* 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.
		*/

		#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

		#include <linux/module.h>
		#include <linux/init.h>
		#include <linux/random.h>
		#include <linux/hw_random.h>
		#include <linux/timer.h>
		#include <linux/clk.h>
		#include <linux/err.h>
		#include <linux/platform_device.h>

		#define RNG_RESET 0x01
		#define RNG_GEN_PRNG_HW_INIT 0x02
		#define RNG_GEN_HW 0x08

		/* param1: ptr, param2: count, param3: flag */
		static u32 (*omap3_rom_rng_call)(u32, u32, u32);

		static struct timer_list idle_timer;
		static int rng_idle;
		static struct clk *rng_clk;

		static void omap3_rom_rng_idle(unsigned long data)
		{
		int r;

		r = omap3_rom_rng_call(0, 0, RNG_RESET);
		if (r != 0) {
		pr_err("reset failed: %d\n", r);
		return;
		}
		clk_disable_unprepare(rng_clk);
		rng_idle = 1;
		}

		static int omap3_rom_rng_get_random(void *buf, unsigned int count)
		{
		u32 r;
		u32 ptr;

		del_timer_sync(&idle_timer);
		if (rng_idle) {
		clk_prepare_enable(rng_clk);
		r = omap3_rom_rng_call(0, 0, RNG_GEN_PRNG_HW_INIT);
		if (r != 0) {
		clk_disable_unprepare(rng_clk);
		pr_err("HW init failed: %d\n", r);
		return -EIO;
		}
		rng_idle = 0;
		}

		ptr = virt_to_phys(buf);
		r = omap3_rom_rng_call(ptr, count, RNG_GEN_HW);
		mod_timer(&idle_timer, jiffies + msecs_to_jiffies(500));
		if (r != 0)
		return -EINVAL;
		return 0;
		}

		static int omap3_rom_rng_data_present(struct hwrng *rng, int wait)
		{
		return 1;
		}

		static int omap3_rom_rng_data_read(struct hwrng rng, u32 data)
		{
		int r;

		r = omap3_rom_rng_get_random(data, 4);
		if (r < 0)
		return r;
		return 4;
		}

		static struct hwrng omap3_rom_rng_ops = {
		.name = "omap3-rom",
		.data_present = omap3_rom_rng_data_present,
		.data_read = omap3_rom_rng_data_read,
		};

		static int omap3_rom_rng_probe(struct platform_device *pdev)
		{
		pr_info("initializing\n");

		omap3_rom_rng_call = pdev->dev.platform_data;
		if (!omap3_rom_rng_call) {
		pr_err("omap3_rom_rng_call is NULL\n");
		return -EINVAL;
		}

		setup_timer(&idle_timer, omap3_rom_rng_idle, 0);
		rng_clk = clk_get(&pdev->dev, "ick");
		if (IS_ERR(rng_clk)) {
		pr_err("unable to get RNG clock\n");
		return PTR_ERR(rng_clk);
		}

		/* Leave the RNG in reset state. */
		clk_prepare_enable(rng_clk);
		omap3_rom_rng_idle(0);

		return hwrng_register(&omap3_rom_rng_ops);
		}

		static int omap3_rom_rng_remove(struct platform_device *pdev)
		{
		hwrng_unregister(&omap3_rom_rng_ops);
		clk_disable_unprepare(rng_clk);
		clk_put(rng_clk);
		return 0;
		}

		static struct platform_driver omap3_rom_rng_driver = {
		.driver = {
		.name = "omap3-rom-rng",
		.owner = THIS_MODULE,
		},
		.probe = omap3_rom_rng_probe,
		.remove = omap3_rom_rng_remove,
		};

		module_platform_driver(omap3_rom_rng_driver);

		MODULE_ALIAS("platform:omap3-rom-rng");
		MODULE_AUTHOR("Juha Yrjola");
		MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
		MODULE_LICENSE("GPL");