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>

1 files changed, 94 insertions, 0 deletions

diff --git a/drivers/char/hw_random/cavium-rng.c b/drivers/char/hw_random/cavium-rng.c
new file mode 100644
index 000000000000..a944e0a47f42
--- /dev/null
+++ b/drivers/char/hw_random/cavium-rng.c
@@ -0,0 +1,94 @@
+/*
+ * 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");