hwrng: cavium - Add Cavium HWRNG driver for ThunderX SoC.

The Cavium ThunderX SoC has a hardware random number generator.
This driver provides support using the HWRNG framework.
Signed-off-by: Omer Khaliq <okhaliq@caviumnetworks.com>
Signed-off-by: Ananth Jasty <Ananth.Jasty@cavium.com>
Acked-by: David Daney <david.daney@cavium.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/char/hw_random/Kconfig

@@ -410,6 +410,19 @@ config HW_RANDOM_MESON
 
 	  If unsure, say Y.
 
+config HW_RANDOM_CAVIUM
+       tristate "Cavium ThunderX Random Number Generator support"
+       depends on HW_RANDOM && PCI && (ARM64 || (COMPILE_TEST && 64BIT))
+       default HW_RANDOM
+       ---help---
+         This driver provides kernel-side support for the Random Number
+         Generator hardware found on Cavium SoCs.
+
+         To compile this driver as a module, choose M here: the
+         module will be called cavium_rng.
+
+         If unsure, say Y.
+
 endif # HW_RANDOM
 
 config UML_RANDOM

drivers/char/hw_random/Makefile

@@ -35,3 +35,4 @@ obj-$(CONFIG_HW_RANDOM_XGENE) += xgene-rng.o
 obj-$(CONFIG_HW_RANDOM_STM32) += stm32-rng.o
 obj-$(CONFIG_HW_RANDOM_PIC32) += pic32-rng.o
 obj-$(CONFIG_HW_RANDOM_MESON) += meson-rng.o
+obj-$(CONFIG_HW_RANDOM_CAVIUM) += cavium-rng.o cavium-rng-vf.o

drivers/char/hw_random/cavium-rng-vf.c

+/*
+ * Hardware Random Number Generator support for Cavium, Inc.
+ * Thunder processor family.
+ *
+ * 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.
+ *
+ * Copyright (C) 2016 Cavium, Inc.
+ */
+
+#include <linux/hw_random.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/pci_ids.h>
+
+struct cavium_rng {
+	struct hwrng ops;
+	void __iomem *result;
+};
+
+/* Read data from the RNG unit */
+static int cavium_rng_read(struct hwrng *rng, void *dat, size_t max, bool wait)
+{
+	struct cavium_rng *p = container_of(rng, struct cavium_rng, ops);
+	unsigned int size = max;
+
+	while (size >= 8) {
+		*((u64 *)dat) = readq(p->result);
+		size -= 8;
+		dat += 8;
+	}
+	while (size > 0) {
+		*((u8 *)dat) = readb(p->result);
+		size--;
+		dat++;
+	}
+	return max;
+}
+
+/* Map Cavium RNG to an HWRNG object */
+static int cavium_rng_probe_vf(struct	pci_dev		*pdev,
+			 const struct	pci_device_id	*id)
+{
+	struct	cavium_rng *rng;
+	int	ret;
+
+	rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
+	if (!rng)
+		return -ENOMEM;
+
+	/* Map the RNG result */
+	rng->result = pcim_iomap(pdev, 0, 0);
+	if (!rng->result) {
+		dev_err(&pdev->dev, "Error iomap failed retrieving result.\n");
+		return -ENOMEM;
+	}
+
+	rng->ops.name    = "cavium rng";
+	rng->ops.read    = cavium_rng_read;
+	rng->ops.quality = 1000;
+
+	pci_set_drvdata(pdev, rng);
+
+	ret = hwrng_register(&rng->ops);
+	if (ret) {
+		dev_err(&pdev->dev, "Error registering device as HWRNG.\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+/* Remove the VF */
+void  cavium_rng_remove_vf(struct pci_dev *pdev)
+{
+	struct cavium_rng *rng;
+
+	rng = pci_get_drvdata(pdev);
+	hwrng_unregister(&rng->ops);
+}
+
+static const struct pci_device_id cavium_rng_vf_id_table[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, 0xa033), 0, 0, 0},
+	{0,},
+};
+MODULE_DEVICE_TABLE(pci, cavium_rng_vf_id_table);
+
+static struct pci_driver cavium_rng_vf_driver = {
+	.name		= "cavium_rng_vf",
+	.id_table	= cavium_rng_vf_id_table,
+	.probe		= cavium_rng_probe_vf,
+	.remove		= cavium_rng_remove_vf,
+};
+module_pci_driver(cavium_rng_vf_driver);
+
+MODULE_AUTHOR("Omer Khaliq <okhaliq@caviumnetworks.com>");
+MODULE_LICENSE("GPL");

drivers/char/hw_random/cavium-rng.c

+/*
+ * Hardware Random Number Generator support for Cavium Inc.
+ * Thunder processor family.
+ *
+ * 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.
+ *
+ * Copyright (C) 2016 Cavium, Inc.
+ */
+
+#include <linux/hw_random.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/pci_ids.h>
+
+#define THUNDERX_RNM_ENT_EN     0x1
+#define THUNDERX_RNM_RNG_EN     0x2
+
+struct cavium_rng_pf {
+	void __iomem *control_status;
+};
+
+/* Enable the RNG hardware and activate the VF */
+static int cavium_rng_probe(struct pci_dev *pdev,
+			const struct pci_device_id *id)
+{
+	struct	cavium_rng_pf *rng;
+	int	iov_err;
+
+	rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
+	if (!rng)
+		return -ENOMEM;
+
+	/*Map the RNG control */
+	rng->control_status = pcim_iomap(pdev, 0, 0);
+	if (!rng->control_status) {
+		dev_err(&pdev->dev,
+			"Error iomap failed retrieving control_status.\n");
+		return -ENOMEM;
+	}
+
+	/* Enable the RNG hardware and entropy source */
+	writeq(THUNDERX_RNM_RNG_EN | THUNDERX_RNM_ENT_EN,
+		rng->control_status);
+
+	pci_set_drvdata(pdev, rng);
+
+	/* Enable the Cavium RNG as a VF */
+	iov_err = pci_enable_sriov(pdev, 1);
+	if (iov_err != 0) {
+		/* Disable the RNG hardware and entropy source */
+		writeq(0, rng->control_status);
+		dev_err(&pdev->dev,
+			"Error initializing RNG virtual function,(%i).\n",
+			iov_err);
+		return iov_err;
+	}
+
+	return 0;
+}
+
+/* Disable VF and RNG Hardware */
+void  cavium_rng_remove(struct pci_dev *pdev)
+{
+	struct cavium_rng_pf *rng;
+
+	rng = pci_get_drvdata(pdev);
+
+	/* Remove the VF */
+	pci_disable_sriov(pdev);
+
+	/* Disable the RNG hardware and entropy source */
+	writeq(0, rng->control_status);
+}
+
+static const struct pci_device_id cavium_rng_pf_id_table[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, 0xa018), 0, 0, 0}, /* Thunder RNM */
+	{0,},
+};
+
+MODULE_DEVICE_TABLE(pci, cavium_rng_pf_id_table);
+
+static struct pci_driver cavium_rng_pf_driver = {
+	.name		= "cavium_rng_pf",
+	.id_table	= cavium_rng_pf_id_table,
+	.probe		= cavium_rng_probe,
+	.remove		= cavium_rng_remove,
+};
+
+module_pci_driver(cavium_rng_pf_driver);
+MODULE_AUTHOR("Omer Khaliq <okhaliq@caviumnetworks.com>");
+MODULE_LICENSE("GPL");