hwrng: iproc-rng200 - Add Broadcom IPROC RNG driver (c83d45d5) · Commits · e / devices / android_kernel_teracube_mt6765

drivers/char/hw_random/Kconfig

+13 −0

Original line number	Diff line number	Diff line
		@@ -101,6 +101,19 @@ config HW_RANDOM_BCM2835

		If unsure, say Y.

		config HW_RANDOM_IPROC_RNG200
		tristate "Broadcom iProc RNG200 support"
		depends on ARCH_BCM_IPROC
		default HW_RANDOM
		---help---
		This driver provides kernel-side support for the RNG200
		hardware found on the Broadcom iProc SoCs.

		To compile this driver as a module, choose M here: the
		module will be called iproc-rng200

		If unsure, say Y.

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

drivers/char/hw_random/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -28,5 +28,6 @@ obj-$(CONFIG_HW_RANDOM_POWERNV) += powernv-rng.o
		obj-$(CONFIG_HW_RANDOM_EXYNOS) += exynos-rng.o
		obj-$(CONFIG_HW_RANDOM_TPM) += tpm-rng.o
		obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o
		obj-$(CONFIG_HW_RANDOM_IPROC_RNG200) += iproc-rng200.o
		obj-$(CONFIG_HW_RANDOM_MSM) += msm-rng.o
		obj-$(CONFIG_HW_RANDOM_XGENE) += xgene-rng.o

drivers/char/hw_random/iproc-rng200.c

0 → 100644

+254 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2015 Broadcom Corporation
		*
		* 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 version 2.
		*
		* This program is distributed "as is" WITHOUT ANY WARRANTY of any
		* kind, whether express or implied; without even the implied warranty
		* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*/
		/*
		* DESCRIPTION: The Broadcom iProc RNG200 Driver
		*/

		#include <linux/hw_random.h>
		#include <linux/init.h>
		#include <linux/io.h>
		#include <linux/kernel.h>
		#include <linux/module.h>
		#include <linux/of_address.h>
		#include <linux/of_platform.h>
		#include <linux/platform_device.h>
		#include <linux/delay.h>

		/* Registers */
		#define RNG_CTRL_OFFSET 0x00
		#define RNG_CTRL_RNG_RBGEN_MASK 0x00001FFF
		#define RNG_CTRL_RNG_RBGEN_ENABLE 0x00000001
		#define RNG_CTRL_RNG_RBGEN_DISABLE 0x00000000

		#define RNG_SOFT_RESET_OFFSET 0x04
		#define RNG_SOFT_RESET 0x00000001

		#define RBG_SOFT_RESET_OFFSET 0x08
		#define RBG_SOFT_RESET 0x00000001

		#define RNG_INT_STATUS_OFFSET 0x18
		#define RNG_INT_STATUS_MASTER_FAIL_LOCKOUT_IRQ_MASK 0x80000000
		#define RNG_INT_STATUS_STARTUP_TRANSITIONS_MET_IRQ_MASK 0x00020000
		#define RNG_INT_STATUS_NIST_FAIL_IRQ_MASK 0x00000020
		#define RNG_INT_STATUS_TOTAL_BITS_COUNT_IRQ_MASK 0x00000001

		#define RNG_FIFO_DATA_OFFSET 0x20

		#define RNG_FIFO_COUNT_OFFSET 0x24
		#define RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK 0x000000FF

		struct iproc_rng200_dev {
		void __iomem *base;
		};

		static void iproc_rng200_restart(void __iomem *rng_base)
		{
		uint32_t val;

		/* Disable RBG */
		val = ioread32(rng_base + RNG_CTRL_OFFSET);
		val &= ~RNG_CTRL_RNG_RBGEN_MASK;
		val \|= RNG_CTRL_RNG_RBGEN_DISABLE;
		iowrite32(val, rng_base + RNG_CTRL_OFFSET);

		/* Clear all interrupt status */
		iowrite32(0xFFFFFFFFUL, rng_base + RNG_INT_STATUS_OFFSET);

		/* Reset RNG and RBG */
		val = ioread32(rng_base + RBG_SOFT_RESET_OFFSET);
		val \|= RBG_SOFT_RESET;
		iowrite32(val, rng_base + RBG_SOFT_RESET_OFFSET);

		val = ioread32(rng_base + RNG_SOFT_RESET_OFFSET);
		val \|= RNG_SOFT_RESET;
		iowrite32(val, rng_base + RNG_SOFT_RESET_OFFSET);

		val = ioread32(rng_base + RNG_SOFT_RESET_OFFSET);
		val &= ~RNG_SOFT_RESET;
		iowrite32(val, rng_base + RNG_SOFT_RESET_OFFSET);

		val = ioread32(rng_base + RBG_SOFT_RESET_OFFSET);
		val &= ~RBG_SOFT_RESET;
		iowrite32(val, rng_base + RBG_SOFT_RESET_OFFSET);

		/* Enable RBG */
		val = ioread32(rng_base + RNG_CTRL_OFFSET);
		val &= ~RNG_CTRL_RNG_RBGEN_MASK;
		val \|= RNG_CTRL_RNG_RBGEN_ENABLE;
		iowrite32(val, rng_base + RNG_CTRL_OFFSET);
		}

		static int iproc_rng200_read(struct hwrng rng, void buf, size_t max,
		bool wait)
		{
		uint32_t status;
		uint32_t num_remaining = max;
		struct iproc_rng200_dev priv = (struct iproc_rng200_dev )rng->priv;

		#define MAX_RESETS_PER_READ 1
		uint32_t num_resets = 0;

		#define MAX_IDLE_TIME (1 * HZ)
		unsigned long idle_endtime = jiffies + MAX_IDLE_TIME;

		while ((num_remaining > 0) && time_before(jiffies, idle_endtime)) {

		/* Is RNG sane? If not, reset it. */
		status = ioread32(priv->base + RNG_INT_STATUS_OFFSET);
		if ((status & (RNG_INT_STATUS_MASTER_FAIL_LOCKOUT_IRQ_MASK \|
		RNG_INT_STATUS_NIST_FAIL_IRQ_MASK)) != 0) {

		if (num_resets >= MAX_RESETS_PER_READ)
		return max - num_remaining;

		iproc_rng200_restart(priv->base);
		num_resets++;
		}

		/* Are there any random numbers available? */
		if ((ioread32(priv->base + RNG_FIFO_COUNT_OFFSET) &
		RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK) > 0) {

		if (num_remaining >= sizeof(uint32_t)) {
		/* Buffer has room to store entire word */
		(uint32_t )buf = ioread32(priv->base +
		RNG_FIFO_DATA_OFFSET);
		buf += sizeof(uint32_t);
		num_remaining -= sizeof(uint32_t);
		} else {
		/* Buffer can only store partial word */
		uint32_t rnd_number = ioread32(priv->base +
		RNG_FIFO_DATA_OFFSET);
		memcpy(buf, &rnd_number, num_remaining);
		buf += num_remaining;
		num_remaining = 0;
		}

		/* Reset the IDLE timeout */
		idle_endtime = jiffies + MAX_IDLE_TIME;
		} else {
		if (!wait)
		/* Cannot wait, return immediately */
		return max - num_remaining;

		/* Can wait, give others chance to run */
		usleep_range(min(num_remaining * 10, 500U), 500);
		}
		}

		return max - num_remaining;
		}

		static int iproc_rng200_init(struct hwrng *rng)
		{
		uint32_t val;
		struct iproc_rng200_dev *priv;

		priv = (struct iproc_rng200_dev *)rng->priv;

		/* Setup RNG. */
		val = ioread32(priv->base + RNG_CTRL_OFFSET);
		val &= ~RNG_CTRL_RNG_RBGEN_MASK;
		val \|= RNG_CTRL_RNG_RBGEN_ENABLE;
		iowrite32(val, priv->base + RNG_CTRL_OFFSET);

		return 0;
		}

		static void iproc_rng200_cleanup(struct hwrng *rng)
		{
		uint32_t val;
		struct iproc_rng200_dev *priv;

		priv = (struct iproc_rng200_dev *)rng->priv;

		/* Disable RNG hardware */
		val = ioread32(priv->base + RNG_CTRL_OFFSET);
		val &= ~RNG_CTRL_RNG_RBGEN_MASK;
		val \|= RNG_CTRL_RNG_RBGEN_DISABLE;
		iowrite32(val, priv->base + RNG_CTRL_OFFSET);
		}

		static struct hwrng iproc_rng200_ops = {
		.name = "iproc-rng200",
		.read = iproc_rng200_read,
		.init = iproc_rng200_init,
		.cleanup = iproc_rng200_cleanup,
		};

		static int iproc_rng200_probe(struct platform_device *pdev)
		{
		struct iproc_rng200_dev *priv;
		struct resource *res;
		struct device *dev = &pdev->dev;
		int ret;

		priv = devm_kzalloc(dev, sizeof(struct iproc_rng200_dev), GFP_KERNEL);
		if (!priv)
		return -ENOMEM;

		iproc_rng200_ops.priv = (unsigned long)priv;
		platform_set_drvdata(pdev, priv);

		/* Map peripheral */
		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
		if (!res) {
		dev_err(dev, "failed to get rng resources\n");
		return -EINVAL;
		}

		priv->base = devm_ioremap_resource(dev, res);
		if (IS_ERR(priv->base)) {
		dev_err(dev, "failed to remap rng regs\n");
		return PTR_ERR(priv->base);
		}

		/* Register driver */
		ret = hwrng_register(&iproc_rng200_ops);
		if (ret) {
		dev_err(dev, "hwrng registration failed\n");
		return ret;
		}

		dev_info(dev, "hwrng registered\n");

		return 0;
		}

		static int iproc_rng200_remove(struct platform_device *pdev)
		{
		/* Unregister driver */
		hwrng_unregister(&iproc_rng200_ops);

		return 0;
		}

		static const struct of_device_id iproc_rng200_of_match[] = {
		{ .compatible = "brcm,iproc-rng200", },
		{},
		};
		MODULE_DEVICE_TABLE(of, iproc_rng200_of_match);

		static struct platform_driver iproc_rng200_driver = {
		.driver = {
		.name = "iproc-rng200",
		.of_match_table = iproc_rng200_of_match,
		},
		.probe = iproc_rng200_probe,
		.remove = iproc_rng200_remove,
		};
		module_platform_driver(iproc_rng200_driver);

		MODULE_AUTHOR("Broadcom");
		MODULE_DESCRIPTION("iProc RNG200 Random Number Generator driver");
		MODULE_LICENSE("GPL v2");