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, 99 insertions, 0 deletions

diff --git a/drivers/char/hw_random/cavium-rng-vf.c b/drivers/char/hw_random/cavium-rng-vf.c
new file mode 100644
index 000000000000..066ae0e78d63
--- /dev/null
+++ b/drivers/char/hw_random/cavium-rng-vf.c
@@ -0,0 +1,99 @@
+/*
+ * 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");