MIPS: hwrng: Add TX4939 RNG driver (049a947c) · Commits · e / devices / android_kernel_fairphone_FP3

drivers/char/hw_random/Kconfig

+13 −0

Original line number	Diff line number	Diff line
		@@ -149,6 +149,19 @@ config HW_RANDOM_VIRTIO
		To compile this driver as a module, choose M here: the
		module will be called virtio-rng. If unsure, say N.

		config HW_RANDOM_TX4939
		tristate "TX4939 Random Number Generator support"
		depends on HW_RANDOM && SOC_TX4939
		default HW_RANDOM
		---help---
		This driver provides kernel-side support for the Random Number
		Generator hardware found on TX4939 SoC.

		To compile this driver as a module, choose M here: the
		module will be called tx4939-rng.

		If unsure, say Y.

		config HW_RANDOM_MXC_RNGA
		tristate "Freescale i.MX RNGA Random Number Generator"
		depends on HW_RANDOM && ARCH_HAS_RNGA

drivers/char/hw_random/Makefile

+1 −0

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		@@ -15,4 +15,5 @@ obj-$(CONFIG_HW_RANDOM_IXP4XX) += ixp4xx-rng.o
		obj-$(CONFIG_HW_RANDOM_OMAP) += omap-rng.o
		obj-$(CONFIG_HW_RANDOM_PASEMI) += pasemi-rng.o
		obj-$(CONFIG_HW_RANDOM_VIRTIO) += virtio-rng.o
		obj-$(CONFIG_HW_RANDOM_TX4939) += tx4939-rng.o
		obj-$(CONFIG_HW_RANDOM_MXC_RNGA) += mxc-rnga.o

drivers/char/hw_random/tx4939-rng.c

0 → 100644

+184 −0

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		/*
		* RNG driver for TX4939 Random Number Generators (RNG)
		*
		* Copyright (C) 2009 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
		*
		* This file is subject to the terms and conditions of the GNU General Public
		* License. See the file "COPYING" in the main directory of this archive
		* for more details.
		*/
		#include <linux/module.h>
		#include <linux/kernel.h>
		#include <linux/init.h>
		#include <linux/delay.h>
		#include <linux/io.h>
		#include <linux/platform_device.h>
		#include <linux/hw_random.h>

		#define TX4939_RNG_RCSR 0x00000000
		#define TX4939_RNG_ROR(n) (0x00000018 + (n) * 8)

		#define TX4939_RNG_RCSR_INTE 0x00000008
		#define TX4939_RNG_RCSR_RST 0x00000004
		#define TX4939_RNG_RCSR_FIN 0x00000002
		#define TX4939_RNG_RCSR_ST 0x00000001

		struct tx4939_rng {
		struct hwrng rng;
		void __iomem *base;
		u64 databuf[3];
		unsigned int data_avail;
		};

		static void rng_io_start(void)
		{
		#ifndef CONFIG_64BIT
		/*
		* readq is reading a 64-bit register using a 64-bit load. On
		* a 32-bit kernel however interrupts or any other processor
		* exception would clobber the upper 32-bit of the processor
		* register so interrupts need to be disabled.
		*/
		local_irq_disable();
		#endif
		}

		static void rng_io_end(void)
		{
		#ifndef CONFIG_64BIT
		local_irq_enable();
		#endif
		}

		static u64 read_rng(void __iomem *base, unsigned int offset)
		{
		return ____raw_readq(base + offset);
		}

		static void write_rng(u64 val, void __iomem *base, unsigned int offset)
		{
		return ____raw_writeq(val, base + offset);
		}

		static int tx4939_rng_data_present(struct hwrng *rng, int wait)
		{
		struct tx4939_rng *rngdev = container_of(rng, struct tx4939_rng, rng);
		int i;

		if (rngdev->data_avail)
		return rngdev->data_avail;
		for (i = 0; i < 20; i++) {
		rng_io_start();
		if (!(read_rng(rngdev->base, TX4939_RNG_RCSR)
		& TX4939_RNG_RCSR_ST)) {
		rngdev->databuf[0] =
		read_rng(rngdev->base, TX4939_RNG_ROR(0));
		rngdev->databuf[1] =
		read_rng(rngdev->base, TX4939_RNG_ROR(1));
		rngdev->databuf[2] =
		read_rng(rngdev->base, TX4939_RNG_ROR(2));
		rngdev->data_avail =
		sizeof(rngdev->databuf) / sizeof(u32);
		/* Start RNG */
		write_rng(TX4939_RNG_RCSR_ST,
		rngdev->base, TX4939_RNG_RCSR);
		wait = 0;
		}
		rng_io_end();
		if (!wait)
		break;
		/* 90 bus clock cycles by default for generation */
		ndelay(90 * 5);
		}
		return rngdev->data_avail;
		}

		static int tx4939_rng_data_read(struct hwrng rng, u32 buffer)
		{
		struct tx4939_rng *rngdev = container_of(rng, struct tx4939_rng, rng);

		rngdev->data_avail--;
		buffer = ((u32 *)&rngdev->databuf + rngdev->data_avail);
		return sizeof(u32);
		}

		static int __init tx4939_rng_probe(struct platform_device *dev)
		{
		struct tx4939_rng *rngdev;
		struct resource *r;
		int i;

		r = platform_get_resource(dev, IORESOURCE_MEM, 0);
		if (!r)
		return -EBUSY;
		rngdev = devm_kzalloc(&dev->dev, sizeof(*rngdev), GFP_KERNEL);
		if (!rngdev)
		return -ENOMEM;
		if (!devm_request_mem_region(&dev->dev, r->start, resource_size(r),
		dev_name(&dev->dev)))
		return -EBUSY;
		rngdev->base = devm_ioremap(&dev->dev, r->start, resource_size(r));
		if (!rngdev->base)
		return -EBUSY;

		rngdev->rng.name = dev_name(&dev->dev);
		rngdev->rng.data_present = tx4939_rng_data_present;
		rngdev->rng.data_read = tx4939_rng_data_read;

		rng_io_start();
		/* Reset RNG */
		write_rng(TX4939_RNG_RCSR_RST, rngdev->base, TX4939_RNG_RCSR);
		write_rng(0, rngdev->base, TX4939_RNG_RCSR);
		/* Start RNG */
		write_rng(TX4939_RNG_RCSR_ST, rngdev->base, TX4939_RNG_RCSR);
		rng_io_end();
		/*
		* Drop first two results. From the datasheet:
		* The quality of the random numbers generated immediately
		* after reset can be insufficient. Therefore, do not use
		* random numbers obtained from the first and second
		* generations; use the ones from the third or subsequent
		* generation.
		*/
		for (i = 0; i < 2; i++) {
		rngdev->data_avail = 0;
		if (!tx4939_rng_data_present(&rngdev->rng, 1))
		return -EIO;
		}

		platform_set_drvdata(dev, rngdev);
		return hwrng_register(&rngdev->rng);
		}

		static int __exit tx4939_rng_remove(struct platform_device *dev)
		{
		struct tx4939_rng *rngdev = platform_get_drvdata(dev);

		hwrng_unregister(&rngdev->rng);
		platform_set_drvdata(dev, NULL);
		return 0;
		}

		static struct platform_driver tx4939_rng_driver = {
		.driver = {
		.name = "tx4939-rng",
		.owner = THIS_MODULE,
		},
		.remove = tx4939_rng_remove,
		};

		static int __init tx4939rng_init(void)
		{
		return platform_driver_probe(&tx4939_rng_driver, tx4939_rng_probe);
		}

		static void __exit tx4939rng_exit(void)
		{
		platform_driver_unregister(&tx4939_rng_driver);
		}

		module_init(tx4939rng_init);
		module_exit(tx4939rng_exit);

		MODULE_DESCRIPTION("H/W Random Number Generator (RNG) driver for TX4939");
		MODULE_LICENSE("GPL");