[PATCH 1/3] powerpc: Implement arch_get_random_long/int() for powernv

[PATCH 1/3] powerpc: Implement arch_get_random_long/int() for powernv

[Michael Ellerman]

Add the plumbing to implement arch_get_random_long/int(). It didn't seem
worth adding an extra ppc_md hook for int, so we reuse the one for long.

Add an implementation for powernv based on the hwrng found in power7+
systems. We whiten the output of the hwrng, and the result passes all
the dieharder tests.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
---
 arch/powerpc/Kconfig                    |   3 +
 arch/powerpc/include/asm/archrandom.h   |  32 +++++++++
 arch/powerpc/include/asm/machdep.h      |   4 ++
 arch/powerpc/platforms/powernv/Kconfig  |   1 +
 arch/powerpc/platforms/powernv/Makefile |   2 +-
 arch/powerpc/platforms/powernv/rng.c    | 122 ++++++++++++++++++++++++++++++++
 6 files changed, 163 insertions(+), 1 deletion(-)
 create mode 100644 arch/powerpc/include/asm/archrandom.h
 create mode 100644 arch/powerpc/platforms/powernv/rng.c

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 38f3b7e..45f16f7 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -1009,6 +1009,9 @@ config PHYSICAL_START
 	default "0x00000000"
 endif
 
+config	ARCH_RANDOM
+	def_bool n
+
 source "net/Kconfig"
 
 source "drivers/Kconfig"
diff --git a/arch/powerpc/include/asm/archrandom.h b/arch/powerpc/include/asm/archrandom.h
new file mode 100644
index 0000000..d853d16
--- /dev/null
+++ b/arch/powerpc/include/asm/archrandom.h
@@ -0,0 +1,32 @@
+#ifndef _ASM_POWERPC_ARCHRANDOM_H
+#define _ASM_POWERPC_ARCHRANDOM_H
+
+#ifdef CONFIG_ARCH_RANDOM
+
+#include <asm/machdep.h>
+
+static inline int arch_get_random_long(unsigned long *v)
+{
+	if (ppc_md.get_random_long)
+		return ppc_md.get_random_long(v);
+
+	return 0;
+}
+
+static inline int arch_get_random_int(unsigned int *v)
+{
+	unsigned long val;
+	int rc;
+
+	rc = arch_get_random_long(&val);
+	if (rc)
+		*v = val;
+
+	return rc;
+}
+
+int powernv_get_random_long(unsigned long *v);
+
+#endif /* CONFIG_ARCH_RANDOM */
+
+#endif /* _ASM_POWERPC_ARCHRANDOM_H */
diff --git a/arch/powerpc/include/asm/machdep.h b/arch/powerpc/include/asm/machdep.h
index 8b48090..ce6cc2a 100644
--- a/arch/powerpc/include/asm/machdep.h
+++ b/arch/powerpc/include/asm/machdep.h
@@ -263,6 +263,10 @@ struct machdep_calls {
 	ssize_t (*cpu_probe)(const char *, size_t);
 	ssize_t (*cpu_release)(const char *, size_t);
 #endif
+
+#ifdef CONFIG_ARCH_RANDOM
+	int (*get_random_long)(unsigned long *v);
+#endif
 };
 
 extern void e500_idle(void);
diff --git a/arch/powerpc/platforms/powernv/Kconfig b/arch/powerpc/platforms/powernv/Kconfig
index 6fae5eb..2108464 100644
--- a/arch/powerpc/platforms/powernv/Kconfig
+++ b/arch/powerpc/platforms/powernv/Kconfig
@@ -9,6 +9,7 @@ config PPC_POWERNV
 	select EPAPR_BOOT
 	select PPC_INDIRECT_PIO
 	select PPC_UDBG_16550
+	select ARCH_RANDOM
 	default y
 
 config POWERNV_MSI
diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
index 300c437..6760a86 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -1,5 +1,5 @@
 obj-y			+= setup.o opal-takeover.o opal-wrappers.o opal.o
-obj-y			+= opal-rtc.o opal-nvram.o opal-lpc.o
+obj-y			+= opal-rtc.o opal-nvram.o opal-lpc.o rng.o
 
 obj-$(CONFIG_SMP)	+= smp.o
 obj-$(CONFIG_PCI)	+= pci.o pci-p5ioc2.o pci-ioda.o
diff --git a/arch/powerpc/platforms/powernv/rng.c b/arch/powerpc/platforms/powernv/rng.c
new file mode 100644
index 0000000..02db7d7
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/rng.c
@@ -0,0 +1,122 @@
+/*
+ * Copyright 2013, Michael Ellerman, 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; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#define pr_fmt(fmt)	"powernv-rng: " fmt
+
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/slab.h>
+#include <asm/archrandom.h>
+#include <asm/io.h>
+#include <asm/machdep.h>
+
+
+struct powernv_rng {
+	void __iomem *regs;
+	unsigned long mask;
+};
+
+static DEFINE_PER_CPU(struct powernv_rng *, powernv_rng);
+
+
+static unsigned long rng_whiten(struct powernv_rng *rng, unsigned long val)
+{
+	unsigned long parity;
+
+	/* Calculate the parity of the value */
+	asm ("popcntd %0,%1" : "=r" (parity) : "r" (val));
+
+	/* xor our value with the previous mask */
+	val ^= rng->mask;
+
+	/* update the mask based on the parity of this value */
+	rng->mask = (rng->mask << 1) | (parity & 1);
+
+	return val;
+}
+
+int powernv_get_random_long(unsigned long *v)
+{
+	struct powernv_rng *rng;
+
+	rng = get_cpu_var(powernv_rng);
+
+	*v = rng_whiten(rng, in_be64(rng->regs));
+
+	put_cpu_var(rng);
+
+	return 1;
+}
+EXPORT_SYMBOL_GPL(powernv_get_random_long);
+
+static __init void rng_init_per_cpu(struct powernv_rng *rng,
+				    struct device_node *dn)
+{
+	int chip_id, cpu;
+
+	chip_id = of_get_ibm_chip_id(dn);
+	if (chip_id == -1)
+		pr_warn("No ibm,chip-id found for %s.\n", dn->full_name);
+
+	for_each_possible_cpu(cpu) {
+		if (per_cpu(powernv_rng, cpu) == NULL ||
+		    cpu_to_chip_id(cpu) == chip_id) {
+			per_cpu(powernv_rng, cpu) = rng;
+		}
+	}
+}
+
+static __init int rng_create(struct device_node *dn)
+{
+	struct powernv_rng *rng;
+	unsigned long val;
+
+	rng = kzalloc(sizeof(*rng), GFP_KERNEL);
+	if (!rng)
+		return -ENOMEM;
+
+	rng->regs = of_iomap(dn, 0);
+	if (!rng->regs) {
+		kfree(rng);
+		return -ENXIO;
+	}
+
+	val = in_be64(rng->regs);
+	rng->mask = val;
+
+	rng_init_per_cpu(rng, dn);
+
+	pr_info_once("Registering arch random hook.\n");
+
+	ppc_md.get_random_long = powernv_get_random_long;
+
+	return 0;
+}
+
+static __init int rng_init(void)
+{
+	struct device_node *dn;
+	int rc;
+
+	for_each_compatible_node(dn, NULL, "ibm,power-rng") {
+		rc = rng_create(dn);
+		if (rc) {
+			pr_err("Failed creating rng for %s (%d).\n",
+				dn->full_name, rc);
+			continue;
+		}
+
+		/* Create devices for hwrng driver */
+		of_platform_device_create(dn, NULL, NULL);
+	}
+
+	return 0;
+}
+subsys_initcall(rng_init);
-- 
1.8.1.2

[PATCH 2/3] hwrng: Add a driver for the hwrng found in power7+ systems

[Michael Ellerman]

Add a driver for the hwrng found in power7+ systems, based on the
existing code for the arch_get_random_long() hook.

We only register a single instance of the driver, not one per device,
because we use the existing per_cpu array of devices in the arch code.
This means we always read from the "closest" device, avoiding inter-chip
memory traffic.

Signed-off-by: Guo Chao <yan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
---
 drivers/char/hw_random/Kconfig       | 13 ++++++
 drivers/char/hw_random/Makefile      |  1 +
 drivers/char/hw_random/powernv-rng.c | 81 ++++++++++++++++++++++++++++++++++++
 3 files changed, 95 insertions(+)
 create mode 100644 drivers/char/hw_random/powernv-rng.c

diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index 0aa9d91..c206de2 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -290,6 +290,19 @@ config HW_RANDOM_PSERIES
 
 	  If unsure, say Y.
 
+config HW_RANDOM_POWERNV
+	tristate "PowerNV Random Number Generator support"
+	depends on HW_RANDOM && PPC_POWERNV
+	default HW_RANDOM
+	---help---
+	  This is the driver for Random Number Generator hardware found
+	  in POWER7+ and above machines for PowerNV platform.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called powernv-rng.
+
+	  If unsure, say Y.
+
 config HW_RANDOM_EXYNOS
 	tristate "EXYNOS HW random number generator support"
 	depends on HW_RANDOM && HAS_IOMEM && HAVE_CLK
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index bed467c..d7d2435 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o
 obj-$(CONFIG_HW_RANDOM_PICOXCELL) += picoxcell-rng.o
 obj-$(CONFIG_HW_RANDOM_PPC4XX) += ppc4xx-rng.o
 obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o
+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
diff --git a/drivers/char/hw_random/powernv-rng.c b/drivers/char/hw_random/powernv-rng.c
new file mode 100644
index 0000000..3f4f632
--- /dev/null
+++ b/drivers/char/hw_random/powernv-rng.c
@@ -0,0 +1,81 @@
+/*
+ * Copyright 2013 Michael Ellerman, Guo Chao, IBM Corp.
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/random.h>
+#include <linux/hw_random.h>
+
+static int powernv_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
+{
+	unsigned long *buf;
+	int i, len;
+
+	/* We rely on rng_buffer_size() being >= sizeof(unsigned long) */
+	len = max / sizeof(unsigned long);
+
+	buf = (unsigned long *)data;
+
+	for (i = 0; i < len; i++)
+		powernv_get_random_long(buf++);
+
+	return len * sizeof(unsigned long);
+}
+
+static struct hwrng powernv_hwrng = {
+	.name = "powernv-rng",
+	.read = powernv_rng_read,
+};
+
+static int powernv_rng_remove(struct platform_device *pdev)
+{
+	hwrng_unregister(&powernv_hwrng);
+
+	return 0;
+}
+
+static int powernv_rng_probe(struct platform_device *pdev)
+{
+	int rc;
+
+	rc = hwrng_register(&powernv_hwrng);
+	if (rc) {
+		/* We only register one device, ignore any others */
+		if (rc == -EEXIST)
+			rc = -ENODEV;
+
+		return rc;
+	}
+
+	pr_info("Registered powernv hwrng.\n");
+
+	return 0;
+}
+
+static struct of_device_id powernv_rng_match[] = {
+	{ .compatible	= "ibm,power-rng",},
+	{},
+};
+MODULE_DEVICE_TABLE(of, powernv_rng_match);
+
+static struct platform_driver powernv_rng_driver = {
+	.driver = {
+		.name = "powernv_rng",
+		.of_match_table = powernv_rng_match,
+	},
+	.probe	= powernv_rng_probe,
+	.remove = powernv_rng_remove,
+};
+module_platform_driver(powernv_rng_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Bare metal HWRNG driver for POWER7+ and above");
-- 
1.8.1.2

[PATCH 3/3] powerpc/pseries: Implement arch_get_random_long() based on H_RANDOM

[Michael Ellerman]

Add support for the arch_get_random_long() hook based on the H_RANDOM
hypervisor call. We trust the hypervisor to provide us with random data,
ie. we don't whiten it in anyway.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
---
 arch/powerpc/platforms/pseries/Makefile |  2 +-
 arch/powerpc/platforms/pseries/rng.c    | 44 +++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 1 deletion(-)
 create mode 100644 arch/powerpc/platforms/pseries/rng.c

diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
index 6c61ec5..fbccac9 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -3,7 +3,7 @@ ccflags-$(CONFIG_PPC_PSERIES_DEBUG)	+= -DDEBUG
 
 obj-y			:= lpar.o hvCall.o nvram.o reconfig.o \
 			   setup.o iommu.o event_sources.o ras.o \
-			   firmware.o power.o dlpar.o mobility.o
+			   firmware.o power.o dlpar.o mobility.o rng.o
 obj-$(CONFIG_SMP)	+= smp.o
 obj-$(CONFIG_SCANLOG)	+= scanlog.o
 obj-$(CONFIG_EEH)	+= eeh_pseries.o
diff --git a/arch/powerpc/platforms/pseries/rng.c b/arch/powerpc/platforms/pseries/rng.c
new file mode 100644
index 0000000..a702f1c
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/rng.c
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2013, Michael Ellerman, 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; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#define pr_fmt(fmt)	"pseries-rng: " fmt
+
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <asm/archrandom.h>
+#include <asm/machdep.h>
+
+
+static int pseries_get_random_long(unsigned long *v)
+{
+	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
+
+	if (plpar_hcall(H_RANDOM, retbuf) == H_SUCCESS) {
+		*v = retbuf[0];
+		return 1;
+	}
+
+	return 0;
+}
+
+static __init int rng_init(void)
+{
+	struct device_node *dn;
+
+	dn = of_find_compatible_node(NULL, NULL, "ibm,random");
+	if (!dn)
+		return -ENODEV;
+
+	pr_info("Registering arch random hook.\n");
+
+	ppc_md.get_random_long = pseries_get_random_long;
+
+	return 0;
+}
+subsys_initcall(rng_init);
-- 
1.8.1.2

Re: [PATCH 1/3] powerpc: Implement arch_get_random_long/int() for powernv

[Benjamin Herrenschmidt]

On Thu, 2013-09-26 at 16:31 +1000, Michael Ellerman wrote:
> +       pr_info_once("registering arch random hook\n");

Either pr_debug or make it nicer looking :-)

Cheers,
Ben.

[PATCH 1/3] powerpc: Implement arch_get_random_long/int() for powernv

[Michael Ellerman]

Add the plumbing to implement arch_get_random_long/int(). It didn't seem
worth adding an extra ppc_md hook for int, so we reuse the one for long.

Add an implementation for powernv based on the hwrng found in power7+
systems. We whiten the output of the hwrng, and the result passes all
the dieharder tests.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
---
 arch/powerpc/Kconfig                    |   3 +
 arch/powerpc/include/asm/archrandom.h   |  32 +++++++++
 arch/powerpc/include/asm/machdep.h      |   4 ++
 arch/powerpc/platforms/powernv/Kconfig  |   1 +
 arch/powerpc/platforms/powernv/Makefile |   2 +-
 arch/powerpc/platforms/powernv/rng.c    | 122 ++++++++++++++++++++++++++++++++
 6 files changed, 163 insertions(+), 1 deletion(-)
 create mode 100644 arch/powerpc/include/asm/archrandom.h
 create mode 100644 arch/powerpc/platforms/powernv/rng.c

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 38f3b7e..45f16f7 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -1009,6 +1009,9 @@ config PHYSICAL_START
 	default "0x00000000"
 endif
 
+config	ARCH_RANDOM
+	def_bool n
+
 source "net/Kconfig"
 
 source "drivers/Kconfig"
diff --git a/arch/powerpc/include/asm/archrandom.h b/arch/powerpc/include/asm/archrandom.h
new file mode 100644
index 0000000..d853d16
--- /dev/null
+++ b/arch/powerpc/include/asm/archrandom.h
@@ -0,0 +1,32 @@
+#ifndef _ASM_POWERPC_ARCHRANDOM_H
+#define _ASM_POWERPC_ARCHRANDOM_H
+
+#ifdef CONFIG_ARCH_RANDOM
+
+#include <asm/machdep.h>
+
+static inline int arch_get_random_long(unsigned long *v)
+{
+	if (ppc_md.get_random_long)
+		return ppc_md.get_random_long(v);
+
+	return 0;
+}
+
+static inline int arch_get_random_int(unsigned int *v)
+{
+	unsigned long val;
+	int rc;
+
+	rc = arch_get_random_long(&val);
+	if (rc)
+		*v = val;
+
+	return rc;
+}
+
+int powernv_get_random_long(unsigned long *v);
+
+#endif /* CONFIG_ARCH_RANDOM */
+
+#endif /* _ASM_POWERPC_ARCHRANDOM_H */
diff --git a/arch/powerpc/include/asm/machdep.h b/arch/powerpc/include/asm/machdep.h
index 8b48090..ce6cc2a 100644
--- a/arch/powerpc/include/asm/machdep.h
+++ b/arch/powerpc/include/asm/machdep.h
@@ -263,6 +263,10 @@ struct machdep_calls {
 	ssize_t (*cpu_probe)(const char *, size_t);
 	ssize_t (*cpu_release)(const char *, size_t);
 #endif
+
+#ifdef CONFIG_ARCH_RANDOM
+	int (*get_random_long)(unsigned long *v);
+#endif
 };
 
 extern void e500_idle(void);
diff --git a/arch/powerpc/platforms/powernv/Kconfig b/arch/powerpc/platforms/powernv/Kconfig
index 6fae5eb..2108464 100644
--- a/arch/powerpc/platforms/powernv/Kconfig
+++ b/arch/powerpc/platforms/powernv/Kconfig
@@ -9,6 +9,7 @@ config PPC_POWERNV
 	select EPAPR_BOOT
 	select PPC_INDIRECT_PIO
 	select PPC_UDBG_16550
+	select ARCH_RANDOM
 	default y
 
 config POWERNV_MSI
diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
index 300c437..6760a86 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -1,5 +1,5 @@
 obj-y			+= setup.o opal-takeover.o opal-wrappers.o opal.o
-obj-y			+= opal-rtc.o opal-nvram.o opal-lpc.o
+obj-y			+= opal-rtc.o opal-nvram.o opal-lpc.o rng.o
 
 obj-$(CONFIG_SMP)	+= smp.o
 obj-$(CONFIG_PCI)	+= pci.o pci-p5ioc2.o pci-ioda.o
diff --git a/arch/powerpc/platforms/powernv/rng.c b/arch/powerpc/platforms/powernv/rng.c
new file mode 100644
index 0000000..51d2e6a
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/rng.c
@@ -0,0 +1,122 @@
+/*
+ * Copyright 2013, Michael Ellerman, 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; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#define pr_fmt(fmt)	"powernv-rng: " fmt
+
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/slab.h>
+#include <asm/archrandom.h>
+#include <asm/io.h>
+#include <asm/machdep.h>
+
+
+struct powernv_rng {
+	void __iomem *regs;
+	unsigned long mask;
+};
+
+static DEFINE_PER_CPU(struct powernv_rng *, powernv_rng);
+
+
+static unsigned long rng_whiten(struct powernv_rng *rng, unsigned long val)
+{
+	unsigned long parity;
+
+	/* Calculate the parity of the value */
+	asm ("popcntd %0,%1" : "=r" (parity) : "r" (val));
+
+	/* xor our value with the previous mask */
+	val ^= rng->mask;
+
+	/* update the mask based on the parity of this value */
+	rng->mask = (rng->mask << 1) | (parity & 1);
+
+	return val;
+}
+
+int powernv_get_random_long(unsigned long *v)
+{
+	struct powernv_rng *rng;
+
+	rng = get_cpu_var(powernv_rng);
+
+	*v = rng_whiten(rng, in_be64(rng->regs));
+
+	put_cpu_var(rng);
+
+	return 1;
+}
+EXPORT_SYMBOL_GPL(powernv_get_random_long);
+
+static __init void rng_init_per_cpu(struct powernv_rng *rng,
+				    struct device_node *dn)
+{
+	int chip_id, cpu;
+
+	chip_id = of_get_ibm_chip_id(dn);
+	if (chip_id == -1)
+		pr_warn("no ibm,chip-id found for %s\n", dn->full_name);
+
+	for_each_possible_cpu(cpu) {
+		if (per_cpu(powernv_rng, cpu) == NULL ||
+		    cpu_to_chip_id(cpu) == chip_id) {
+			per_cpu(powernv_rng, cpu) = rng;
+		}
+	}
+}
+
+static __init int rng_create(struct device_node *dn)
+{
+	struct powernv_rng *rng;
+	unsigned long val;
+
+	rng = kzalloc(sizeof(*rng), GFP_KERNEL);
+	if (!rng)
+		return -ENOMEM;
+
+	rng->regs = of_iomap(dn, 0);
+	if (!rng->regs) {
+		kfree(rng);
+		return -ENXIO;
+	}
+
+	val = in_be64(rng->regs);
+	rng->mask = val;
+
+	rng_init_per_cpu(rng, dn);
+
+	pr_info_once("registering arch random hook\n");
+
+	ppc_md.get_random_long = powernv_get_random_long;
+
+	return 0;
+}
+
+static __init int rng_init(void)
+{
+	struct device_node *dn;
+	int rc;
+
+	for_each_compatible_node(dn, NULL, "ibm,power-rng") {
+		rc = rng_create(dn);
+		if (rc) {
+			pr_err("failed creating rng for %s (%d)\n",
+				dn->full_name, rc);
+			continue;
+		}
+
+		/* Create devices for hwrng driver */
+		of_platform_device_create(dn, NULL, NULL);
+	}
+
+	return 0;
+}
+subsys_initcall(rng_init);
-- 
1.8.1.2