diff --git a/Documentation/devicetree/bindings/net/cavium-mdio.txt b/Documentation/devicetree/bindings/net/cavium-mdio.txt
index 04cb749..020df08 100644
--- a/Documentation/devicetree/bindings/net/cavium-mdio.txt
+++ b/Documentation/devicetree/bindings/net/cavium-mdio.txt
@@ -1,9 +1,12 @@
 * System Management Interface (SMI) / MDIO
 
 Properties:
-- compatible: "cavium,octeon-3860-mdio"
+- compatible: One of:
 
-  Compatibility with all cn3XXX, cn5XXX and cn6XXX SOCs.
+   "cavium,octeon-3860-mdio": Compatibility with all cn3XXX, cn5XXX
+                       and cn6XXX SOCs.
+
+   "cavium,thunder-8890-mdio": Compatibility with all cn8XXX SOCs.
 
 - reg: The base address of the MDIO bus controller register bank.
 
@@ -25,3 +28,57 @@ Example:
 			reg = <0>;
 		};
 	};
+
+
+* System Management Interface (SMI) / MDIO Nexus
+
+  Several mdio buses may be gathered as children of a single PCI
+  device, this PCI device is the nexus of the buses.
+
+Properties:
+
+- compatible: "cavium,thunder-8890-mdio-nexus";
+
+- reg: The PCI device and function numbers of the nexus device.
+
+- #address-cells: Must be <2>.
+
+- #size-cells: Must be <2>.
+
+- ranges: As needed for mapping of the MDIO bus device registers.
+
+- assigned-addresses: As needed for mapping of the MDIO bus device registers.
+
+Example:
+
+        mdio-nexus@1,3 {
+                compatible = "cavium,thunder-8890-mdio-nexus";
+                #address-cells = <2>;
+                #size-cells = <2>;
+                reg = <0x0b00 0 0 0 0>; /* DEVFN = 0x0b (1:3) */
+                assigned-addresses = <0x03000000 0x87e0 0x05000000 0x0 0x800000>;
+                ranges = <0x87e0 0x05000000 0x03000000 0x87e0 0x05000000 0x0 0x800000>;
+
+                mdio0@87e0,05003800 {
+                        compatible = "cavium,thunder-8890-mdio";
+                        #address-cells = <1>;
+                        #size-cells = <0>;
+                        reg = <0x87e0 0x05003800 0x0 0x30>;
+
+                        ethernet-phy@0 {
+                                ...
+                                reg = <0>;
+                        };
+                };
+                mdio0@87e0,05003880 {
+                        compatible = "cavium,thunder-8890-mdio";
+                        #address-cells = <1>;
+                        #size-cells = <0>;
+                        reg = <0x87e0 0x05003880 0x0 0x30>;
+
+                        ethernet-phy@0 {
+                                ...
+                                reg = <0>;
+                        };
+                };
+        };
diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 40faec9..075a4cc 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -196,6 +196,17 @@ config MDIO_OCTEON
 	  buses. It is required by the Octeon and ThunderX ethernet device
 	  drivers on some systems.
 
+config MDIO_THUNDER
+	tristate "Support for MDIO buses on on ThunderX SOCs"
+	depends on 64BIT
+	depends on PCI
+	select MDIO_CAVIUM
+	help
+	  This driver supports the MDIO interfaces found on Cavium
+	  ThunderX SoCs when the MDIO bus device appears on as a PCI
+	  device.
+
+
 config MDIO_SUN4I
 	tristate "Allwinner sun4i MDIO interface support"
 	depends on ARCH_SUNXI
diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index 041b3d9..fcdbb92 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -31,6 +31,7 @@ obj-$(CONFIG_DP83867_PHY)	+= dp83867.o
 obj-$(CONFIG_STE10XP)		+= ste10Xp.o
 obj-$(CONFIG_MICREL_PHY)	+= micrel.o
 obj-$(CONFIG_MDIO_OCTEON)	+= mdio-octeon.o
+obj-$(CONFIG_MDIO_THUNDER)	+= mdio-thunder.o
 obj-$(CONFIG_MDIO_CAVIUM)	+= mdio-cavium.o
 obj-$(CONFIG_MICREL_KS8995MA)	+= spi_ks8995.o
 obj-$(CONFIG_AT803X_PHY)	+= at803x.o
diff --git a/drivers/net/phy/mdio-thunder.c b/drivers/net/phy/mdio-thunder.c
new file mode 100644
index 0000000..5646169
--- /dev/null
+++ b/drivers/net/phy/mdio-thunder.c
@@ -0,0 +1,154 @@
+/*
+ * 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) 2009-2016 Cavium, Inc.
+ */
+
+#include <linux/of_address.h>
+#include <linux/of_mdio.h>
+#include <linux/module.h>
+#include <linux/gfp.h>
+#include <linux/phy.h>
+#include <linux/io.h>
+#include <linux/acpi.h>
+#include <linux/pci.h>
+
+#include "mdio-cavium.h"
+
+struct thunder_mdiobus_nexus {
+	void __iomem *bar0;
+	struct cavium_mdiobus *buses[4];
+};
+
+static int thunder_mdiobus_pci_probe(struct pci_dev *pdev,
+				     const struct pci_device_id *ent)
+{
+	struct device_node *node;
+	struct fwnode_handle *fwn;
+	struct thunder_mdiobus_nexus *nexus;
+	int err;
+	int i;
+
+	nexus = devm_kzalloc(&pdev->dev, sizeof(*nexus), GFP_KERNEL);
+	if (!nexus)
+		return -ENOMEM;
+
+	pci_set_drvdata(pdev, nexus);
+
+	err = pcim_enable_device(pdev);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to enable PCI device\n");
+		pci_set_drvdata(pdev, NULL);
+		return err;
+	}
+
+	err = pci_request_regions(pdev, KBUILD_MODNAME);
+	if (err) {
+		dev_err(&pdev->dev, "pci_request_regions failed\n");
+		goto err_disable_device;
+	}
+
+	nexus->bar0 = pcim_iomap(pdev, 0, pci_resource_len(pdev, 0));
+	if (!nexus->bar0) {
+		err = -ENOMEM;
+		goto err_release_regions;
+	}
+
+	i = 0;
+	device_for_each_child_node(&pdev->dev, fwn) {
+		struct resource r;
+		struct mii_bus *mii_bus;
+		struct cavium_mdiobus *bus;
+		union cvmx_smix_en smi_en;
+
+		/* If it is not an OF node we cannot handle it yet, so
+		 * exit the loop.
+		 */
+		node = to_of_node(fwn);
+		if (!node)
+			break;
+
+		err = of_address_to_resource(node, 0, &r);
+		if (err) {
+			dev_err(&pdev->dev,
+				"Couldn't translate address for \"%s\"\n",
+				node->name);
+			break;
+		}
+
+		mii_bus = devm_mdiobus_alloc_size(&pdev->dev, sizeof(*bus));
+		if (!mii_bus)
+			break;
+		bus = mii_bus->priv;
+		bus->mii_bus = mii_bus;
+
+		nexus->buses[i] = bus;
+		i++;
+
+		bus->register_base = (u64)nexus->bar0 +
+			r.start - pci_resource_start(pdev, 0);
+
+		smi_en.u64 = 0;
+		smi_en.s.en = 1;
+		oct_mdio_writeq(smi_en.u64, bus->register_base + SMI_EN);
+		bus->mii_bus->name = KBUILD_MODNAME;
+		snprintf(bus->mii_bus->id, MII_BUS_ID_SIZE, "%llx", r.start);
+		bus->mii_bus->parent = &pdev->dev;
+		bus->mii_bus->read = cavium_mdiobus_read;
+		bus->mii_bus->write = cavium_mdiobus_write;
+
+		err = of_mdiobus_register(bus->mii_bus, node);
+		if (err)
+			dev_err(&pdev->dev, "of_mdiobus_register failed\n");
+
+		dev_info(&pdev->dev, "Added bus at %llx\n", r.start);
+		if (i >= ARRAY_SIZE(nexus->buses))
+			break;
+	}
+	return 0;
+
+err_release_regions:
+	pci_release_regions(pdev);
+
+err_disable_device:
+	pci_set_drvdata(pdev, NULL);
+	return err;
+}
+
+static void thunder_mdiobus_pci_remove(struct pci_dev *pdev)
+{
+	int i;
+	struct thunder_mdiobus_nexus *nexus = pci_get_drvdata(pdev);
+
+	for (i = 0; i < ARRAY_SIZE(nexus->buses); i++) {
+		struct cavium_mdiobus *bus = nexus->buses[i];
+
+		if (!bus)
+			continue;
+
+		mdiobus_unregister(bus->mii_bus);
+		mdiobus_free(bus->mii_bus);
+		oct_mdio_writeq(0, bus->register_base + SMI_EN);
+	}
+	pci_set_drvdata(pdev, NULL);
+}
+
+static const struct pci_device_id thunder_mdiobus_id_table[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, 0xa02b) },
+	{ 0, } /* End of table. */
+};
+MODULE_DEVICE_TABLE(pci, thunder_mdiobus_id_table);
+
+static struct pci_driver thunder_mdiobus_driver = {
+	.name = KBUILD_MODNAME,
+	.id_table = thunder_mdiobus_id_table,
+	.probe = thunder_mdiobus_pci_probe,
+	.remove = thunder_mdiobus_pci_remove,
+};
+
+module_pci_driver(thunder_mdiobus_driver);
+
+MODULE_DESCRIPTION("Cavium ThunderX MDIO bus driver");
+MODULE_LICENSE("GPL");
