hwrng: ppc4xx - add support for ppc4xx TRNG (52527cf3) · Commits · e / devices / android_kernel_fairphone_FP5

drivers/char/hw_random/Kconfig

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		@@ -210,3 +210,15 @@ config HW_RANDOM_PICOXCELL
		module will be called picoxcell-rng.

		If unsure, say Y.

		config HW_RANDOM_PPC4XX
		tristate "PowerPC 4xx generic true random number generator support"
		depends on HW_RANDOM && PPC && 4xx
		---help---
		This driver provides the kernel-side support for the TRNG hardware
		found in the security function of some PowerPC 4xx SoCs.

		To compile this driver as a module, choose M here: the
		module will be called ppc4xx-rng.

		If unsure, say N.

drivers/char/hw_random/Makefile

+1 −0

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		@@ -20,3 +20,4 @@ obj-$(CONFIG_HW_RANDOM_MXC_RNGA) += mxc-rnga.o
		obj-$(CONFIG_HW_RANDOM_OCTEON) += octeon-rng.o
		obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o
		obj-$(CONFIG_HW_RANDOM_PICOXCELL) += picoxcell-rng.o
		obj-$(CONFIG_HW_RANDOM_PPC4XX) += ppc4xx-rng.o

drivers/char/hw_random/ppc4xx-rng.c

0 → 100644

+156 −0

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		/*
		* Generic PowerPC 44x RNG driver
		*
		* Copyright 2011 IBM 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 of the License.
		*/

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

		#define PPC4XX_TRNG_DEV_CTRL 0x60080

		#define PPC4XX_TRNGE 0x00020000
		#define PPC4XX_TRNG_CTRL 0x0008
		#define PPC4XX_TRNG_CTRL_DALM 0x20
		#define PPC4XX_TRNG_STAT 0x0004
		#define PPC4XX_TRNG_STAT_B 0x1
		#define PPC4XX_TRNG_DATA 0x0000

		#define MODULE_NAME "ppc4xx_rng"

		static int ppc4xx_rng_data_present(struct hwrng *rng, int wait)
		{
		void __iomem rng_regs = (void __iomem ) rng->priv;
		int busy, i, present = 0;

		for (i = 0; i < 20; i++) {
		busy = (in_le32(rng_regs + PPC4XX_TRNG_STAT) & PPC4XX_TRNG_STAT_B);
		if (!busy \|\| !wait) {
		present = 1;
		break;
		}
		udelay(10);
		}
		return present;
		}

		static int ppc4xx_rng_data_read(struct hwrng rng, u32 data)
		{
		void __iomem rng_regs = (void __iomem ) rng->priv;
		*data = in_le32(rng_regs + PPC4XX_TRNG_DATA);
		return 4;
		}

		static int ppc4xx_rng_enable(int enable)
		{
		struct device_node *ctrl;
		void __iomem *ctrl_reg;
		int err = 0;
		u32 val;

		/* Find the main crypto device node and map it to turn the TRNG on */
		ctrl = of_find_compatible_node(NULL, NULL, "amcc,ppc4xx-crypto");
		if (!ctrl)
		return -ENODEV;

		ctrl_reg = of_iomap(ctrl, 0);
		if (!ctrl_reg) {
		err = -ENODEV;
		goto out;
		}

		val = in_le32(ctrl_reg + PPC4XX_TRNG_DEV_CTRL);

		if (enable)
		val \|= PPC4XX_TRNGE;
		else
		val = val & ~PPC4XX_TRNGE;

		out_le32(ctrl_reg + PPC4XX_TRNG_DEV_CTRL, val);
		iounmap(ctrl_reg);

		out:
		of_node_put(ctrl);

		return err;
		}

		static struct hwrng ppc4xx_rng = {
		.name = MODULE_NAME,
		.data_present = ppc4xx_rng_data_present,
		.data_read = ppc4xx_rng_data_read,
		};

		static int __devinit ppc4xx_rng_probe(struct platform_device *dev)
		{
		void __iomem *rng_regs;
		int err = 0;

		rng_regs = of_iomap(dev->dev.of_node, 0);
		if (!rng_regs)
		return -ENODEV;

		err = ppc4xx_rng_enable(1);
		if (err)
		return err;

		out_le32(rng_regs + PPC4XX_TRNG_CTRL, PPC4XX_TRNG_CTRL_DALM);
		ppc4xx_rng.priv = (unsigned long) rng_regs;

		err = hwrng_register(&ppc4xx_rng);

		return err;
		}

		static int __devexit ppc4xx_rng_remove(struct platform_device *dev)
		{
		void __iomem rng_regs = (void __iomem ) ppc4xx_rng.priv;

		hwrng_unregister(&ppc4xx_rng);
		ppc4xx_rng_enable(0);
		iounmap(rng_regs);

		return 0;
		}

		static struct of_device_id ppc4xx_rng_match[] = {
		{ .compatible = "ppc4xx-rng", },
		{ .compatible = "amcc,ppc460ex-rng", },
		{ .compatible = "amcc,ppc440epx-rng", },
		{},
		};

		static struct platform_driver ppc4xx_rng_driver = {
		.driver = {
		.name = MODULE_NAME,
		.owner = THIS_MODULE,
		.of_match_table = ppc4xx_rng_match,
		},
		.probe = ppc4xx_rng_probe,
		.remove = ppc4xx_rng_remove,
		};

		static int __init ppc4xx_rng_init(void)
		{
		return platform_driver_register(&ppc4xx_rng_driver);
		}
		module_init(ppc4xx_rng_init);

		static void __exit ppc4xx_rng_exit(void)
		{
		platform_driver_unregister(&ppc4xx_rng_driver);
		}
		module_exit(ppc4xx_rng_exit);

		MODULE_LICENSE("GPL");
		MODULE_AUTHOR("Josh Boyer <jwboyer@linux.vnet.ibm.com>");
		MODULE_DESCRIPTION("HW RNG driver for PPC 4xx processors");