[PATCH] Add Ingenic JZ4780 hardware RNG driver

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This patch adds support for hardware random number generator present in
JZ4780 SoC.

Signed-off-by: PrasannaKumar Muralidharan <prasannatsmkumar@xxxxxxxxx>
---
 .../devicetree/bindings/rng/ingenic,jz4780-rng.txt |  12 +++
 MAINTAINERS                                        |   5 +
 arch/mips/boot/dts/ingenic/jz4780.dtsi             |   7 +-
 drivers/char/hw_random/Kconfig                     |  14 +++
 drivers/char/hw_random/Makefile                    |   1 +
 drivers/char/hw_random/jz4780-rng.c                | 105 +++++++++++++++++++++
 6 files changed, 143 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/rng/ingenic,jz4780-rng.txt
 create mode 100644 drivers/char/hw_random/jz4780-rng.c

diff --git a/Documentation/devicetree/bindings/rng/ingenic,jz4780-rng.txt b/Documentation/devicetree/bindings/rng/ingenic,jz4780-rng.txt
new file mode 100644
index 0000000..03abf56
--- /dev/null
+++ b/Documentation/devicetree/bindings/rng/ingenic,jz4780-rng.txt
@@ -0,0 +1,12 @@
+Ingenic jz4780 RNG driver
+
+Required properties:
+- compatible : Should be "ingenic,jz4780-rng"
+- reg : Specifies base physical address and size of the registers.
+
+Example:
+
+rng: rng@100000D8 {
+	compatible = "ingenic,jz4780-rng";
+	reg = <0x100000D8 0x8>;
+};
diff --git a/MAINTAINERS b/MAINTAINERS
index 08e9efe..c0c66eb 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6002,6 +6002,11 @@ M:	Zubair Lutfullah Kakakhel <Zubair.Kakakhel@xxxxxxxxxx>
 S:	Maintained
 F:	drivers/dma/dma-jz4780.c
 
+INGENIC JZ4780 HW RNG Driver
+M:	PrasannaKumar Muralidharan <prasannatsmkumar@xxxxxxxxx>
+S:	Maintained
+F:	drivers/char/hw_random/jz4780-rng.c
+
 INTEGRITY MEASUREMENT ARCHITECTURE (IMA)
 M:	Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
 M:	Dmitry Kasatkin <dmitry.kasatkin@xxxxxxxxx>
diff --git a/arch/mips/boot/dts/ingenic/jz4780.dtsi b/arch/mips/boot/dts/ingenic/jz4780.dtsi
index b868b42..f11d139 100644
--- a/arch/mips/boot/dts/ingenic/jz4780.dtsi
+++ b/arch/mips/boot/dts/ingenic/jz4780.dtsi
@@ -36,7 +36,7 @@
 
 	cgu: jz4780-cgu@10000000 {
 		compatible = "ingenic,jz4780-cgu";
-		reg = <0x10000000 0x100>;
+		reg = <0x10000000 0xD8>;
 
 		clocks = <&ext>, <&rtc>;
 		clock-names = "ext", "rtc";
@@ -44,6 +44,11 @@
 		#clock-cells = <1>;
 	};
 
+	rng: jz4780-rng@100000D8 {
+		compatible = "ingenic,jz4780-rng";
+		reg = <0x100000D8 0x8>;
+	};
+
 	uart0: serial@10030000 {
 		compatible = "ingenic,jz4780-uart";
 		reg = <0x10030000 0x100>;
diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index 56ad5a59..c336fe8 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -294,6 +294,20 @@ config HW_RANDOM_POWERNV
 
 	  If unsure, say Y.
 
+config HW_RANDOM_JZ4780
+	tristate "JZ4780 HW random number generator support"
+	depends on MACH_INGENIC
+	depends on HAS_IOMEM
+	default HW_RANDOM
+	---help---
+	  This driver provides kernel-side support for the Random Number
+	  Generator hardware found on JZ4780 SOCs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called jz4780-rng.
+
+	  If unsure, say Y.
+
 config HW_RANDOM_EXYNOS
 	tristate "EXYNOS HW random number generator support"
 	depends on ARCH_EXYNOS || COMPILE_TEST
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index 04bb0b0..a155066 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -26,6 +26,7 @@ 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_HISI)	+= hisi-rng.o
+obj-$(CONFIG_HW_RANDOM_JZ4780)	+= jz4780-rng.o
 obj-$(CONFIG_HW_RANDOM_TPM) += tpm-rng.o
 obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o
 obj-$(CONFIG_HW_RANDOM_IPROC_RNG200) += iproc-rng200.o
diff --git a/drivers/char/hw_random/jz4780-rng.c b/drivers/char/hw_random/jz4780-rng.c
new file mode 100644
index 0000000..c9d2cde
--- /dev/null
+++ b/drivers/char/hw_random/jz4780-rng.c
@@ -0,0 +1,105 @@
+/*
+ * jz4780-rng.c - Random Number Generator driver for J4780
+ *
+ * Copyright 2016 (C) PrasannaKumar Muralidharan <prasannatsmkumar@xxxxxxxxx>
+ *
+ * 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.
+ */
+
+#include <linux/hw_random.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/err.h>
+
+#define REG_RNG_CTRL	0x0
+#define REG_RNG_DATA	0x4
+
+struct jz4780_rng {
+	struct device *dev;
+	struct hwrng rng;
+	void __iomem *mem;
+};
+
+static u32 jz4780_rng_readl(struct jz4780_rng *rng, u32 offset)
+{
+	return readl(rng->mem + offset);
+}
+
+static void jz4780_rng_writel(struct jz4780_rng *rng, u32 val, u32 offset)
+{
+	writel(val, rng->mem + offset);
+}
+
+static int jz4780_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
+{
+	struct jz4780_rng *jz4780_rng = container_of(rng, struct jz4780_rng,
+							rng);
+	u32 *data = buf;
+	*data = jz4780_rng_readl(jz4780_rng, REG_RNG_DATA);
+	return 4;
+}
+
+static int jz4780_rng_probe(struct platform_device *pdev)
+{
+	struct jz4780_rng *jz4780_rng;
+	struct resource *res;
+	resource_size_t size;
+	int ret;
+
+	jz4780_rng = devm_kzalloc(&pdev->dev, sizeof(struct jz4780_rng),
+					GFP_KERNEL);
+	if (!jz4780_rng)
+		return -ENOMEM;
+
+	jz4780_rng->dev = &pdev->dev;
+	jz4780_rng->rng.name = "jz4780";
+	jz4780_rng->rng.read = jz4780_rng_read;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	size = resource_size(res);
+
+	jz4780_rng->mem = devm_ioremap(&pdev->dev, res->start, size);
+	if (IS_ERR(jz4780_rng->mem))
+		return PTR_ERR(jz4780_rng->mem);
+
+	platform_set_drvdata(pdev, jz4780_rng);
+	jz4780_rng_writel(jz4780_rng, 1, REG_RNG_CTRL);
+	ret = hwrng_register(&jz4780_rng->rng);
+
+	return ret;
+}
+
+static int jz4780_rng_remove(struct platform_device *pdev)
+{
+	struct jz4780_rng *jz4780_rng = platform_get_drvdata(pdev);
+
+	jz4780_rng_writel(jz4780_rng, 0, REG_RNG_CTRL);
+	hwrng_unregister(&jz4780_rng->rng);
+
+	return 0;
+}
+
+static const struct of_device_id jz4780_rng_dt_match[] = {
+	{ .compatible = "ingenic,jz4780-rng", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, jz4780_rng_dt_match);
+
+static struct platform_driver jz4780_rng_driver = {
+	.driver		= {
+		.name	= "jz4780-rng",
+		.of_match_table = jz4780_rng_dt_match,
+	},
+	.probe		= jz4780_rng_probe,
+	.remove		= jz4780_rng_remove,
+};
+module_platform_driver(jz4780_rng_driver);
+
+MODULE_DESCRIPTION("Ingenic JZ4780 H/W Random Number Generator driver");
+MODULE_AUTHOR("PrasannaKumar Muralidharan <prasannatsmkumar@xxxxxxxxx>");
+MODULE_LICENSE("GPL");
-- 
2.5.0

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