Driver for non-standard on-chip ethernet device ARC EMAC 10/100,
instantiated in some legacy ARC (Synopsys) FPGA Boards such as
ARCAngel4/ML50x.

This is based off of current Linus tree, build tested for x86.

Signed-off-by: Alexey Brodkin <abrod...@synopsys.com>
Reviewed-by: Vineet Gupta <vgu...@synopsys.com>
Reviewed-by: Mischa Jonker <mjon...@synopsys.com>

Cc: Vineet Gupta <vgu...@synopsys.com>
Cc: Mischa Jonker <mjon...@synopsys.com>
Cc: Arnd Bergmann <a...@arndb.de>
Cc: Grant Likely <grant.lik...@linaro.org>
Cc: Rob Herring <rob.herr...@calxeda.com>
Cc: Paul Gortmaker <paul.gortma...@windriver.com>
Cc: "David S. Miller" <da...@davemloft.net>
Cc: linux-kernel@vger.kernel.org
Cc: devicetree-disc...@lists.ozlabs.org

---
Hi all,

this is v2 respin of "arc_emac" driver.
Please find summary of changes below.

 * Cosmetics as suggested by David Miller - mostly identation fixes in
accordance to the CodingStyle
 * Get rid of extra header "arc_emac_main.h". Its contents moved right
into "arc_emac_main.c"
 * Merge PHY description in "Ethernet" entry in DT so it could be
accessed by "of_mdiobus_register".
 * Add dependences from OF_NET and OF_IRQ in Kconfig to make sure all
needed functions are avaialable.
 * Add DT binding description.
 * Use "void __iomem *" pointers for MMIO mappings instead of simple
"void *"
 * Use "devm_ioremap_resource" instead of pair:
"devm_request_mem_region" & "devm_ioremap_nocache"
---
 Documentation/devicetree/bindings/net/arc_emac.txt |   32 +
 drivers/net/ethernet/Kconfig                       |    1 +
 drivers/net/ethernet/Makefile                      |    1 +
 drivers/net/ethernet/arc/Kconfig                   |   31 +
 drivers/net/ethernet/arc/Makefile                  |    6 +
 drivers/net/ethernet/arc/arc_emac_main.c           |  956 ++++++++++++++++++++
 drivers/net/ethernet/arc/arc_emac_mdio.c           |  170 ++++
 drivers/net/ethernet/arc/arc_emac_mdio.h           |   22 +
 drivers/net/ethernet/arc/arc_emac_regs.h           |   72 ++
 9 files changed, 1291 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/net/arc_emac.txt
 create mode 100644 drivers/net/ethernet/arc/Kconfig
 create mode 100644 drivers/net/ethernet/arc/Makefile
 create mode 100644 drivers/net/ethernet/arc/arc_emac_main.c
 create mode 100644 drivers/net/ethernet/arc/arc_emac_mdio.c
 create mode 100644 drivers/net/ethernet/arc/arc_emac_mdio.h
 create mode 100644 drivers/net/ethernet/arc/arc_emac_regs.h

diff --git a/Documentation/devicetree/bindings/net/arc_emac.txt 
b/Documentation/devicetree/bindings/net/arc_emac.txt
new file mode 100644
index 0000000..4205581
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/arc_emac.txt
@@ -0,0 +1,32 @@
+* Synopsys ARC EMAC 10/100 Ethernet driver (EMAC)
+
+Required properties:
+- compatible: Should be "snps,arc-emac"
+- reg: Address and length of the register set for the device
+- interrupts: Should contain the EMAC interrupts
+- clock-frequency: CPU frequency. It is needed to calculate and set polling
+period of EMAC.
+- phy: PHY device attached to the EMAC via MDIO bus
+
+Child nodes of the driver are the individual PHY devices connected to the
+MDIO bus. They must have a "reg" property given the PHY address on the MDIO 
bus.
+
+Optional properties:
+- mac-address: 6 bytes, mac address
+
+Examples:
+
+       ethernet@c0fc2000 {
+               compatible = "snps,arc-emac";
+               reg = <0xc0fc2000 0x3c>;
+               interrupts = <6>;
+               mac-address = [ 00 11 22 33 44 55 ];
+               clock-frequency = <80000000>;
+               phy = <&phy0>;
+
+               #address-cells = <1>;
+               #size-cells = <0>;
+               phy0: ethernet-phy@0 {
+                       reg = <1>;
+               };
+       };
diff --git a/drivers/net/ethernet/Kconfig b/drivers/net/ethernet/Kconfig
index 4bedae2..98eec48 100644
--- a/drivers/net/ethernet/Kconfig
+++ b/drivers/net/ethernet/Kconfig
@@ -23,6 +23,7 @@ source "drivers/net/ethernet/aeroflex/Kconfig"
 source "drivers/net/ethernet/alteon/Kconfig"
 source "drivers/net/ethernet/amd/Kconfig"
 source "drivers/net/ethernet/apple/Kconfig"
+source "drivers/net/ethernet/arc/Kconfig"
 source "drivers/net/ethernet/atheros/Kconfig"
 source "drivers/net/ethernet/cadence/Kconfig"
 source "drivers/net/ethernet/adi/Kconfig"
diff --git a/drivers/net/ethernet/Makefile b/drivers/net/ethernet/Makefile
index 183e3f4..b764c73 100644
--- a/drivers/net/ethernet/Makefile
+++ b/drivers/net/ethernet/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_GRETH) += aeroflex/
 obj-$(CONFIG_NET_VENDOR_ALTEON) += alteon/
 obj-$(CONFIG_NET_VENDOR_AMD) += amd/
 obj-$(CONFIG_NET_VENDOR_APPLE) += apple/
+obj-$(CONFIG_NET_VENDOR_ARC) += arc/
 obj-$(CONFIG_NET_VENDOR_ATHEROS) += atheros/
 obj-$(CONFIG_NET_CADENCE) += cadence/
 obj-$(CONFIG_NET_BFIN) += adi/
diff --git a/drivers/net/ethernet/arc/Kconfig b/drivers/net/ethernet/arc/Kconfig
new file mode 100644
index 0000000..514c57f
--- /dev/null
+++ b/drivers/net/ethernet/arc/Kconfig
@@ -0,0 +1,31 @@
+#
+# ARC EMAC network device configuration
+#
+
+config NET_VENDOR_ARC
+       bool "ARC devices"
+       default y
+       ---help---
+         If you have a network (Ethernet) card belonging to this class, say Y
+         and read the Ethernet-HOWTO, available from
+         <http://www.tldp.org/docs.html#howto>.
+
+         Note that the answer to this question doesn't directly affect the
+         kernel: saying N will just cause the configurator to skip all
+         the questions about ARC cards. If you say Y, you will be asked for
+         your specific card in the following questions.
+
+if NET_VENDOR_ARC
+
+config ARC_EMAC
+       tristate "ARC EMAC support"
+       select MII
+       select PHYLIB
+       depends on OF_IRQ
+       depends on OF_NET
+       ---help---
+         On some legacy ARC (Synopsys) FPGA boards such as ARCAngel4/ML50x
+         non-standard on-chip ethernet device ARC EMAC 10/100 is used.
+         Say Y here if you have such a board.  If unsure, say N.
+
+endif # NET_VENDOR_ARC
diff --git a/drivers/net/ethernet/arc/Makefile 
b/drivers/net/ethernet/arc/Makefile
new file mode 100644
index 0000000..f5b73e5
--- /dev/null
+++ b/drivers/net/ethernet/arc/Makefile
@@ -0,0 +1,6 @@
+#
+# Makefile for the ARC network device drivers.
+#
+
+arc_emac-objs := arc_emac_main.o arc_emac_mdio.o
+obj-$(CONFIG_ARC_EMAC) += arc_emac.o
diff --git a/drivers/net/ethernet/arc/arc_emac_main.c 
b/drivers/net/ethernet/arc/arc_emac_main.c
new file mode 100644
index 0000000..f098a27
--- /dev/null
+++ b/drivers/net/ethernet/arc/arc_emac_main.c
@@ -0,0 +1,956 @@
+/*
+ * Copyright (C) 2004, 2007-2010, 2011-2013 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Driver for the ARC EMAC 10100 (Rev 5)
+ *
+ * Alexey Brodkin: June 2013
+ *  -Upsteaming
+ *  -Refactoring
+ *      = Use device-tree/OF for configuration
+ *      = Use libphy for phy management
+ *      = Remove non-NAPI code sections
+ *      = Remove ARC-specific BD management implementations
+ *      = Add ethtool functionality
+ *
+ * Vineet Gupta: June 2011
+ *  -Issues when working with 64b cache line size
+ *      = BD rings point to aligned location in an internal buffer
+ *      = added support for cache coherent BD Ring memory
+ *
+ * Vineet Gupta: May 2010
+ *  -Reduced foot-print of the main ISR (handling for error cases moved out
+ *      into a separate non-inline function).
+ *  -Driver Tx path optimized for small packets (which fit into 1 BD = 2K).
+ *      Any specifics for chaining are in a separate block of code.
+ *
+ * Vineet Gupta: Nov 2009
+ *  -Unified NAPI and Non-NAPI Code.
+ *  -API changes since 2.6.26 for making NAPI independent of netdevice
+ *  -Cutting a few checks in main Rx poll routine
+ *  -Tweaked NAPI implementation:
+ *      In poll mode, Original driver would always start sweeping BD chain
+ *      from BD-0 upto poll budget (40). And if it got over-budget it would
+ *      drop reminder of packets.
+ *      Instead now we remember last BD polled and in next
+ *      cycle, we resume from next BD onwards. That way in case of over-budget
+ *      no packet needs to be dropped.
+ *
+ * Vineet Gupta: Nov 2009
+ *  -Rewrote the driver register access macros so that multiple accesses
+ *   in same function use "anchor" reg to save the base addr causing
+ *   shorter instructions
+ *
+ * Amit Bhor, Sameer Dhavale: 2004
+ */
+
+#include <linux/etherdevice.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_mdio.h>
+#include <linux/of_net.h>
+#include <linux/of_platform.h>
+
+#include "arc_emac_regs.h"
+#include "arc_emac_mdio.h"
+
+#define DRV_NAME       "arc_emac"
+#define DRV_VERSION    "2.0"
+
+/* Transmission timeout */
+#define TX_TIMEOUT (400*HZ/1000)
+
+#define NAPI_WEIGHT 40         /* Workload for NAPI */
+
+#define TX_FIFO_SIZE 0x800     /* EMAC Tx FIFO size */
+
+/* Assuming MTU=1500 (IP pkt: hdr+payload), we round off to next cache-line
+ * boundary: 1536 % {32,64,128} == 0
+ * This provides enough space for Ethernet header (14) and also ensures that
+ * buf-size passed to EMAC > max pkt rx (1514). Latter is due to a EMAC quirk
+ * wherein it can generate a chained pkt (with all data in first part, and
+ * an empty 2nd part - albeit with last bit set) when Rx-pkt-sz is exactly
+ * equal to buf-size: hence the need to keep buf-size slightly bigger than
+ * largest pkt.
+ */
+#define        EMAC_BUFFER_PAD 36
+
+struct arc_emac_bd_t {
+       unsigned int info;
+       void *data;
+};
+
+/* Number of Rx/Tx BD's */
+#define RX_BD_NUM      128
+#define TX_BD_NUM      128
+
+#define RX_RING_SZ  (RX_BD_NUM * sizeof(struct arc_emac_bd_t))
+#define TX_RING_SZ  (TX_BD_NUM * sizeof(struct arc_emac_bd_t))
+
+struct arc_emac_priv {
+       struct net_device_stats stats;
+       unsigned int clock_frequency;
+
+       /* Pointers to BD rings - CPU side */
+       struct arc_emac_bd_t *rxbd;
+       struct arc_emac_bd_t *txbd;
+
+       /* Pointers to BD rings - Device side */
+       dma_addr_t rxbd_dma_hdl;
+       dma_addr_t txbd_dma_hdl;
+
+       /* The actual socket buffers */
+       struct sk_buff *rx_skbuff[RX_BD_NUM];
+       struct sk_buff *tx_skbuff[TX_BD_NUM];
+       unsigned int txbd_curr;
+       unsigned int txbd_dirty;
+
+       /* Remember where driver last saw a packet, so next iteration it
+        * starts from here and not 0
+        */
+       unsigned int last_rx_bd;
+
+       struct napi_struct napi;
+
+       /* Storage for "arc_emac_adjust_link" */
+       int old_link;
+       int old_speed;
+       int old_duplex;
+
+       /* Devices */
+       struct device_node *phy_node;
+       struct phy_device *phy_dev;
+       struct net_device *net_dev;
+
+       /* MDIO private structure */
+       struct arc_mdio_priv *mdio_priv;
+
+       /* EMAC registers base address */
+       void __iomem *reg_base_addr;
+};
+
+/**
+ * arc_emac_adjust_link - Adjust the PHY link speed/duplex.
+ * @net_dev:   Pointer to the net_device structure.
+ *
+ * This function is called to change the speed and duplex setting after
+ * auto negotiation is done by the PHY.
+ */
+static void arc_emac_adjust_link(struct net_device *net_dev)
+{
+       struct arc_emac_priv *priv = netdev_priv(net_dev);
+       struct phy_device *phydev = priv->phy_dev;
+       unsigned int reg, status_change = 0;
+
+       BUG_ON(!priv->phy_dev);
+
+       if (phydev->link && (priv->old_speed != phydev->speed)) {
+               /* speed changed */
+               switch (phydev->speed) {
+               case SPEED_10:
+               case SPEED_100:
+                       break;
+               default:
+                       netdev_warn(net_dev, "Speed (%d) is not 10/100?\n",
+                                   phydev->speed);
+                       break;
+               }
+               priv->old_speed = phydev->speed;
+               status_change = 1;
+       }
+
+       if (phydev->link && (priv->old_duplex != phydev->duplex)) {
+               /* duplex mode changed */
+               reg = EMAC_REG_GET(priv->reg_base_addr, R_CTRL);
+
+               if (DUPLEX_FULL == phydev->duplex)
+                       reg |= ENFL_MASK;
+               else
+                       reg &= ~ENFL_MASK;
+
+               EMAC_REG_SET(priv->reg_base_addr, R_CTRL, reg);
+               priv->old_duplex = phydev->duplex;
+               status_change = 1;
+       }
+
+       if (phydev->link != priv->old_link) {
+               /* link state changed */
+               if (!phydev->link) {
+                       /* link went down */
+                       priv->old_speed = 0;
+                       priv->old_duplex = -1;
+               }
+               priv->old_link = phydev->link;
+               status_change = 1;
+       }
+
+       if (status_change)
+               phy_print_status(phydev);
+}
+
+/**
+ * arc_emac_get_settings - Get PHY settings.
+ * @net_dev:   Pointer to net_device structure.
+ * @cmd:               Pointer to ethtool_cmd structure.
+ *
+ * This implements ethtool command for getting PHY settings. If PHY could
+ * not be found, the function returns -ENODEV. This function calls the
+ * relevant PHY ethtool API to get the PHY settings.
+ * Issue "ethtool ethX" under linux prompt to execute this function.
+ */
+static int arc_emac_get_settings(struct net_device *net_dev,
+                                struct ethtool_cmd *cmd)
+{
+       struct arc_emac_priv *priv = netdev_priv(net_dev);
+
+       if (priv->phy_dev)
+               return phy_ethtool_gset(priv->phy_dev, cmd);
+
+       return -EINVAL;
+}
+
+/**
+ * arc_emac_set_settings - Set PHY settings as passed in the argument.
+ * @net_dev:   Pointer to net_device structure.
+ * @cmd:               Pointer to ethtool_cmd structure.
+ *
+ * This implements ethtool command for setting various PHY settings. If PHY
+ * could not be found, the function returns -ENODEV. This function calls the
+ * relevant PHY ethtool API to set the PHY.
+ * Issue e.g. "ethtool -s ethX speed 1000" under linux prompt to execute this
+ * function.
+ */
+static int arc_emac_set_settings(struct net_device *net_dev,
+                                struct ethtool_cmd *cmd)
+{
+       struct arc_emac_priv *priv = netdev_priv(net_dev);
+
+       if (!capable(CAP_NET_ADMIN))
+               return -EPERM;
+
+       if (priv->phy_dev)
+               return phy_ethtool_sset(priv->phy_dev, cmd);
+
+       return -EINVAL;
+}
+
+/**
+ * arc_emac_get_drvinfo - Get EMAC driver information.
+ * @net_dev:   Pointer to net_device structure.
+ * @info:              Pointer to ethtool_drvinfo structure.
+ *
+ * This implements ethtool command for getting the driver information.
+ * Issue "ethtool -i ethX" under linux prompt to execute this function.
+ */
+static void arc_emac_get_drvinfo(struct net_device *net_dev,
+                                struct ethtool_drvinfo *info)
+{
+       strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
+       strlcpy(info->version, DRV_VERSION, sizeof(info->version));
+}
+
+static const struct ethtool_ops arc_emac_ethtool_ops = {
+       .get_settings = arc_emac_get_settings,
+       .set_settings = arc_emac_set_settings,
+       .get_drvinfo = arc_emac_get_drvinfo,
+       .get_link = ethtool_op_get_link,
+};
+
+static int arc_emac_poll(struct napi_struct *napi, int budget)
+{
+       struct net_device *net_dev = napi->dev;
+       struct arc_emac_priv *priv = netdev_priv(net_dev);
+       struct sk_buff *skb, *skbnew;
+       unsigned int i, loop, len, info, work_done = 0;
+
+       /* Loop thru the BD chain, but not always from 0.
+        * Start from right after where we last saw a packet.
+        */
+       i = priv->last_rx_bd;
+
+       for (loop = 0; loop < RX_BD_NUM; loop++) {
+               i = (i + 1) & (RX_BD_NUM - 1);
+
+               info = priv->rxbd[i].info;
+
+               /* BD contains a packet for CPU to grab */
+               if (likely((info & OWN_MASK) == FOR_CPU)) {
+
+                       /* Make a note that we saw a packet at this BD.
+                        * So next time, driver starts from this + 1
+                        */
+                       priv->last_rx_bd = i;
+
+                       /* Packet fits in one BD (Non Fragmented) */
+                       if (likely((info & (FRST_MASK | LAST_MASK)) ==
+                           (FRST_MASK | LAST_MASK))) {
+
+                               len = info & LEN_MASK;
+                               priv->stats.rx_packets++;
+                               priv->stats.rx_bytes += len;
+                               skb = priv->rx_skbuff[i];
+
+                               /* Get a new SKB from stack */
+                               skbnew = netdev_alloc_skb(net_dev,
+                                                         net_dev->mtu +
+                                                         EMAC_BUFFER_PAD);
+
+                               if (!skbnew) {
+                                       netdev_err(net_dev, "Out of memory, "
+                                                  "dropping packet\n");
+
+                                       /* Return buffer to EMAC */
+                                       priv->rxbd[i].info = FOR_EMAC |
+                                              (net_dev->mtu + EMAC_BUFFER_PAD);
+                                       priv->stats.rx_dropped++;
+                                       continue;
+                               }
+
+                               /* Actually preparing the BD for next cycle
+                                * IP header align, eth is 14 bytes
+                                */
+                               skb_reserve(skbnew, 2);
+                               priv->rx_skbuff[i] = skbnew;
+
+                               priv->rxbd[i].data = skbnew->data;
+                               priv->rxbd[i].info = FOR_EMAC |
+                                              (net_dev->mtu + EMAC_BUFFER_PAD);
+
+                               /* Prepare arrived pkt for delivery to stack */
+                               dma_map_single(&net_dev->dev, (void *)skb->data,
+                                              len, DMA_FROM_DEVICE);
+
+                               skb->dev = net_dev;
+
+                               /* Make room for data */
+                               skb_put(skb, len - 4);
+                               skb->protocol = eth_type_trans(skb, net_dev);
+
+                               /* Correct NAPI semantics:
+                                * If work quota exceeded return don't de-queue
+                                * any further packets
+                                */
+                               work_done++;
+                               netif_receive_skb(skb);
+                               if (work_done >= budget)
+                                       break;
+                       } else {
+                               /* Buffer chaining results in a significant
+                                * amount of additional bus overhead and thus
+                                * a higher CLK frequency is required or larger
+                                * FIFOs are required.
+                                * Because of that fact we don't support
+                                * chaining of receive packets. We preallocate
+                                * buffers of MTU size so incoming packets
+                                * won't be chained
+                                */
+                               netdev_warn(net_dev,
+                                           "Rx chained, packet is larger than "
+                                           "device MTU (%d bytes)\n",
+                                           net_dev->mtu);
+
+                               /* Return buffer to EMAC */
+                               priv->rxbd[i].info = FOR_EMAC |
+                                              (net_dev->mtu + EMAC_BUFFER_PAD);
+                               priv->stats.rx_length_errors++;
+                       }
+               }       /* BD for CPU */
+       }               /* BD chain loop */
+
+       if (work_done < budget) {
+               napi_complete(napi);
+               EMAC_REG_OR(priv->reg_base_addr, R_ENABLE, RXINT_MASK);
+       }
+
+       return work_done;
+}
+
+/**
+ * arc_emac_intr - Global interrupt handler for EMAC.
+ * @irq:               irq number.
+ * @net_dev:   net_device pointer.
+ *
+ * returns: IRQ_HANDLED for all cases.
+ *
+ * ARC EMAC has only 1 interrupt line, and depending on bits raised in
+ * STATUS register we may tell what is a reason for interrupt to fire.
+ */
+static irqreturn_t arc_emac_intr(int irq, void *dev_instance)
+{
+       struct net_device *net_dev = (struct net_device *)dev_instance;
+       struct arc_emac_priv *priv = netdev_priv(net_dev);
+       unsigned int status;
+
+       /* Read STATUS register from EMAC */
+       status = EMAC_REG_GET(priv->reg_base_addr, R_STATUS);
+
+       /* Mask all bits except "MDIO complete" */
+       status &= ~MDIO_MASK;
+
+       /* To reset any bit in STATUS register we need to write "1" in
+        * corresponding bit. That's why we write only masked bits back.
+        */
+       EMAC_REG_SET(priv->reg_base_addr, R_STATUS, status);
+
+       if (likely(status & (RXINT_MASK | TXINT_MASK))) {
+               if (status & RXINT_MASK) {
+                       if (likely(napi_schedule_prep(&priv->napi))) {
+                               EMAC_REG_CLR(priv->reg_base_addr, R_ENABLE,
+                                            RXINT_MASK);
+                               __napi_schedule(&priv->napi);
+                       }
+               }
+               if (status & TXINT_MASK) {
+                       unsigned int i, info;
+                       struct sk_buff *skb;
+
+                       for (i = 0; i < TX_BD_NUM; i++) {
+                               info = priv->txbd[priv->txbd_dirty].info;
+
+                               if (info & (DROP | DEFR | LTCL | UFLO))
+                                       netdev_warn(net_dev,
+                                                   "add Tx errors to stats\n");
+
+                               if ((info & FOR_EMAC) ||
+                                       !priv->txbd[priv->txbd_dirty].data)
+                                       break;
+
+                               if (info & LAST_MASK) {
+                                       skb = priv->tx_skbuff[priv->txbd_dirty];
+                                       priv->stats.tx_packets++;
+                                       priv->stats.tx_bytes += skb->len;
+
+                                       /* return the sk_buff to system */
+                                       dev_kfree_skb_irq(skb);
+                               }
+                               priv->txbd[priv->txbd_dirty].data = 0x0;
+                               priv->txbd[priv->txbd_dirty].info = 0x0;
+                               priv->txbd_dirty = (priv->txbd_dirty + 1) %
+                                                                     TX_BD_NUM;
+                       }
+               }
+       } else {
+               if (status & ERR_MASK) {
+                       /* MSER/RXCR/RXFR/RXFL interrupt fires on corresponding
+                        * 8-bit error counter overrun.
+                        * Because of this fact we add 256 items each time
+                        * overrun interrupt happens.
+                        */
+
+                       if (status & TXCH_MASK) {
+                               priv->stats.tx_errors++;
+                               priv->stats.tx_aborted_errors++;
+                               netdev_err(priv->net_dev,
+                                          "Tx chaining err! txbd_dirty = %u\n",
+                                          priv->txbd_dirty);
+                       } else if (status & MSER_MASK) {
+                               priv->stats.rx_missed_errors += 255;
+                               priv->stats.rx_errors += 255;
+                       } else if (status & RXCR_MASK) {
+                               priv->stats.rx_crc_errors += 255;
+                               priv->stats.rx_errors += 255;
+                       } else if (status & RXFR_MASK) {
+                               priv->stats.rx_frame_errors += 255;
+                               priv->stats.rx_errors += 255;
+                       } else if (status & RXFL_MASK) {
+                               priv->stats.rx_over_errors += 255;
+                               priv->stats.rx_errors += 255;
+                       } else {
+                               netdev_err(priv->net_dev,
+                                          "unknown err. Status reg is 0x%x\n",
+                                          status);
+                       }
+               }
+       }
+       return IRQ_HANDLED;
+}
+
+/**
+ * arc_emac_open - Open the network device.
+ * @net_dev:   Pointer to the network device.
+ *
+ * returns: 0, on success or non-zero error value on failure.
+ *
+ * This function sets the MAC address, requests and enables an IRQ
+ * for the EMAC device and starts the Tx queue.
+ * It also connects to the phy device.
+ */
+int arc_emac_open(struct net_device *net_dev)
+{
+       struct arc_emac_priv *priv = netdev_priv(net_dev);
+       struct arc_emac_bd_t *bd;
+       struct sk_buff *skb;
+       int i;
+
+       if (!priv->phy_node) {
+               netdev_err(net_dev, "arc_emac_open: phy device is absent\n");
+               return -ENODEV;
+       }
+
+       priv->phy_dev = of_phy_connect(net_dev, priv->phy_node,
+                                      arc_emac_adjust_link, 0,
+                                      PHY_INTERFACE_MODE_MII);
+
+       if (!priv->phy_dev) {
+               netdev_err(net_dev, "of_phy_connect() failed\n");
+               return -ENODEV;
+       }
+
+       netdev_info(net_dev, "connected to %s phy with id 0x%x\n",
+                   priv->phy_dev->drv->name, priv->phy_dev->phy_id);
+
+       priv->phy_dev->autoneg = AUTONEG_ENABLE;
+       priv->phy_dev->speed = 0;
+       priv->phy_dev->duplex = 0;
+
+       /* We support only up-to 100mbps speeds */
+       priv->phy_dev->advertising = priv->phy_dev->supported;
+       priv->phy_dev->advertising &= PHY_BASIC_FEATURES;
+       priv->phy_dev->advertising |= ADVERTISED_Autoneg;
+
+       /* Restart auto negotiation */
+       phy_start_aneg(priv->phy_dev);
+
+       netif_start_queue(net_dev);
+
+       /* Allocate and set buffers for Rx BD's */
+       bd = priv->rxbd;
+       for (i = 0; i < RX_BD_NUM; i++) {
+               skb = netdev_alloc_skb(net_dev, net_dev->mtu + EMAC_BUFFER_PAD);
+
+               /* IP header Alignment (14 byte Ethernet header) */
+               skb_reserve(skb, 2);
+               priv->rx_skbuff[i] = skb;
+               bd->data = skb->data;
+
+               /* EMAC owns Rx descriptors */
+               bd->info = FOR_EMAC | (net_dev->mtu + EMAC_BUFFER_PAD);
+               bd++;
+       }
+
+       /* setup last seen to MAX, so driver starts from 0 */
+       priv->last_rx_bd = RX_BD_NUM - 1;
+
+       /* Allocate Tx BD's similar to Rx BD's. All Tx BD's owned by CPU */
+       bd = priv->txbd;
+       for (i = 0; i < TX_BD_NUM; i++) {
+               bd->data = 0;
+               bd->info = 0;
+               bd++;
+       }
+
+       /* Initialize logical address filter */
+       EMAC_REG_SET(priv->reg_base_addr, R_LAFL, 0);
+       EMAC_REG_SET(priv->reg_base_addr, R_LAFH, 0);
+
+       /* Set BD ring pointers for device side */
+       EMAC_REG_SET(priv->reg_base_addr, R_RX_RING,
+                    (unsigned int)priv->rxbd_dma_hdl);
+
+       EMAC_REG_SET(priv->reg_base_addr, R_TX_RING,
+                    (unsigned int)priv->rxbd_dma_hdl + RX_RING_SZ);
+
+       /* Set Poll rate so that it polls every 1 ms */
+       EMAC_REG_SET(priv->reg_base_addr, R_POLLRATE,
+                    priv->clock_frequency / 1000000);
+
+       /* Enable interrupts. Note: interrupts wont actually come till we set
+        * CONTROL below.
+        */
+       EMAC_REG_SET(priv->reg_base_addr, R_ENABLE,
+                    TXINT_MASK |       /* Transmit interrupt */
+                    RXINT_MASK |       /* Receive interrupt */
+                    ERR_MASK |         /* Error interrupt */
+                    TXCH_MASK |        /* Transmit chaining error interrupt */
+                    MSER_MASK);        /* Missed packet error */
+
+       /* Set CONTROL */
+       EMAC_REG_SET(priv->reg_base_addr, R_CTRL,
+                    (RX_BD_NUM << 24) |        /* RX buffer desc table len */
+                    (TX_BD_NUM << 16) |        /* TX buffer desc table len */
+                    TXRN_MASK |                /* TX enable */
+                    RXRN_MASK);                /* RX enable */
+
+       EMAC_REG_OR(priv->reg_base_addr, R_CTRL, EN_MASK);
+
+       netif_wake_queue(net_dev);
+       napi_enable(&priv->napi);
+
+       return 0;
+}
+
+/**
+ * arc_emac_stop - Close the network device.
+ * @net_dev:   Pointer to the network device.
+ *
+ * This function stops the Tx queue, disables interrupts and frees the IRQ for
+ * the EMAC device.
+ * It also disconnects the phy device associated with the EMAC device.
+ */
+int arc_emac_stop(struct net_device *net_dev)
+{
+       struct arc_emac_priv *priv = netdev_priv(net_dev);
+
+       napi_disable(&priv->napi);
+       netif_stop_queue(net_dev);
+
+       /* Disable interrupts */
+       EMAC_REG_CLR(priv->reg_base_addr, R_ENABLE,
+                    TXINT_MASK |       /* Tx interrupt */
+                    RXINT_MASK |       /* Rx interrupt */
+                    ERR_MASK |         /* Error interrupt */
+                    TXCH_MASK);        /* Transmit chaining error interrupt */
+
+       if (priv->phy_dev)
+               phy_disconnect(priv->phy_dev);
+
+       priv->phy_dev = NULL;
+
+       /* Disable EMAC */
+       EMAC_REG_CLR(priv->reg_base_addr, R_CTRL, EN_MASK);
+
+       return 0;
+}
+
+/**
+ * arc_emac_stats - Get system network statistics.
+ * @net_dev:   Pointer to net_device structure.
+ *
+ * Returns the address of the device statistics structure.
+ * Statistics are updated in interrupt handler.
+ */
+struct net_device_stats *arc_emac_stats(struct net_device *net_dev)
+{
+       unsigned long miss, rxerr, rxfram, rxcrc, rxoflow;
+       struct arc_emac_priv *priv = netdev_priv(net_dev);
+
+       rxerr = EMAC_REG_GET(priv->reg_base_addr, R_RXERR);
+       miss = EMAC_REG_GET(priv->reg_base_addr, R_MISS);
+
+       rxcrc = (rxerr & 0xff);
+       rxfram = (rxerr >> 8 & 0xff);
+       rxoflow = (rxerr >> 16 & 0xff);
+
+       priv->stats.rx_errors += miss;
+       priv->stats.rx_errors += rxcrc + rxfram + rxoflow;
+
+       priv->stats.rx_over_errors += rxoflow;
+       priv->stats.rx_frame_errors += rxfram;
+       priv->stats.rx_crc_errors += rxcrc;
+       priv->stats.rx_missed_errors += miss;
+
+       return &priv->stats;
+}
+
+/**
+ * arc_emac_tx - Starts the data transmission.
+ * @skb:               sk_buff pointer that contains data to be Transmitted.
+ * @net_dev:   Pointer to net_device structure.
+ *
+ * returns: NETDEV_TX_OK, on success
+ *             NETDEV_TX_BUSY, if any of the descriptors are not free.
+ *
+ * This function is invoked from upper layers to initiate transmission.
+ */
+int arc_emac_tx(struct sk_buff *skb, struct net_device *net_dev)
+{
+       int len, bitmask;
+       unsigned int info;
+       char *pkt;
+       struct arc_emac_priv *priv = netdev_priv(net_dev);
+
+       len = skb->len < ETH_ZLEN ? ETH_ZLEN : skb->len;
+       pkt = skb->data;
+       net_dev->trans_start = jiffies;
+
+       dma_map_single(&net_dev->dev, (void *)pkt, len, DMA_TO_DEVICE);
+
+       /* Set first bit */
+       bitmask = FRST_MASK;
+
+tx_next_chunk:
+
+       info = priv->txbd[priv->txbd_curr].info;
+       if (likely((info & OWN_MASK) == FOR_CPU)) {
+               priv->txbd[priv->txbd_curr].data = pkt;
+
+               /* This case handles 2 scenarios:
+                * 1. pkt fits into 1 BD (2k)
+                * 2. Last chunk of pkt (in multiples of 2k)
+                */
+               if (likely(len <= TX_FIFO_SIZE)) {
+                       priv->tx_skbuff[priv->txbd_curr] = skb;
+
+                       /* Set data length, bit mask and give ownership to
+                        * EMAC This should be the last thing we do. EMAC
+                        * might immediately start sending
+                        */
+                       priv->txbd[priv->txbd_curr].info = FOR_EMAC | bitmask |
+                                                               LAST_MASK | len;
+
+                       /* Set TXPOLL bit to force a poll */
+                       EMAC_REG_SET(priv->reg_base_addr, R_STATUS, TXPL_MASK);
+
+                       priv->txbd_curr = (priv->txbd_curr + 1) % TX_BD_NUM;
+                       return NETDEV_TX_OK;
+               } else {
+                       /* if pkt > 2k, this case handles all non last chunks */
+                       priv->txbd[priv->txbd_curr].info = FOR_EMAC | bitmask |
+                                                    (len & (TX_FIFO_SIZE - 1));
+
+                       /* clear the FIRST CHUNK bit */
+                       bitmask = 0;
+
+                       len -= TX_FIFO_SIZE;
+               }
+
+               priv->txbd_curr = (priv->txbd_curr + 1) % TX_BD_NUM;
+               goto tx_next_chunk;
+
+       } else {
+               return NETDEV_TX_BUSY;
+       }
+}
+
+/**
+ * arc_emac_set_address - Set the MAC address for this device.
+ * @net_dev:   Pointer to net_device structure.
+ * @p:                 6 byte Address to be written as MAC address.
+ *
+ * This function copies the HW address from the sockaddr structure to the
+ * net_device structure and updates the address in HW.
+ *
+ * returns:    -EBUSY if the net device is busy or 0 if the address is set
+ *             successfully.
+ */
+int arc_emac_set_address(struct net_device *net_dev, void *p)
+{
+       struct sockaddr *addr = p;
+       struct arc_emac_priv *priv = netdev_priv(net_dev);
+
+       if (netif_running(net_dev))
+               return -EBUSY;
+
+       memcpy(net_dev->dev_addr, addr->sa_data, net_dev->addr_len);
+
+       EMAC_REG_SET(priv->reg_base_addr, R_ADDRL,
+                    *(unsigned int *)net_dev->dev_addr);
+
+       EMAC_REG_SET(priv->reg_base_addr, R_ADDRH,
+                    *(unsigned int *)&net_dev->dev_addr[4] & 0x0000ffff);
+
+       return 0;
+}
+
+static const struct net_device_ops arc_emac_netdev_ops = {
+       .ndo_open = arc_emac_open,
+       .ndo_stop = arc_emac_stop,
+       .ndo_start_xmit = arc_emac_tx,
+       .ndo_set_mac_address = arc_emac_set_address,
+       .ndo_get_stats = arc_emac_stats,
+};
+
+static int arc_emac_probe(struct platform_device *pdev)
+{
+       struct net_device *net_dev;
+       struct arc_emac_priv *priv;
+       int err;
+       unsigned int id, clock_frequency;
+       struct resource res_regs, res_irq;
+       const char *mac_addr = NULL;
+
+       /* no device tree device */
+       if (!pdev->dev.of_node)
+               return -ENODEV;
+
+       net_dev = alloc_etherdev(sizeof(struct arc_emac_priv));
+       if (!net_dev) {
+               err = -ENOMEM;
+               goto out;
+       }
+
+       SET_NETDEV_DEV(net_dev, &pdev->dev);
+
+       /* Populate our net_device structure */
+       net_dev->netdev_ops = &arc_emac_netdev_ops;
+       net_dev->ethtool_ops = &arc_emac_ethtool_ops;
+       net_dev->watchdog_timeo = TX_TIMEOUT;
+       /* FIXME :: no multicast support yet */
+       net_dev->flags &= ~IFF_MULTICAST;
+
+       priv = netdev_priv(net_dev);
+       priv->net_dev = net_dev;
+
+       /* Get phy from device tree */
+       priv->phy_node = of_parse_phandle(pdev->dev.of_node, "phy", 0);
+       if (!priv->phy_node) {
+               dev_err(&pdev->dev, "failed to retrieve phy description "
+                       "from device tree\n");
+               err = -ENODEV;
+               goto out;
+       }
+
+       /* Get EMAC registers base address from device tree */
+       err = of_address_to_resource(pdev->dev.of_node, 0, &res_regs);
+       if (err) {
+               dev_err(&pdev->dev, "failed to retrieve registers base "
+                       "from device tree\n");
+               err = -ENODEV;
+               goto out;
+       }
+
+       priv->reg_base_addr = devm_ioremap_resource(&pdev->dev, &res_regs);
+       if (IS_ERR(priv->reg_base_addr)) {
+               dev_err(&pdev->dev, "failed to ioremap MAC registers\n");
+               err = PTR_ERR(priv->reg_base_addr);
+               goto out;
+       }
+       dev_dbg(&pdev->dev, "Registers base address is 0x%p\n",
+               priv->reg_base_addr);
+
+       id = EMAC_REG_GET(priv->reg_base_addr, R_ID);
+       /* Check for EMAC revision 5 or 7, magic number */
+       if (!(id == 0x0005fd02 || id == 0x0007fd02)) {
+               dev_err(&pdev->dev, "ARC EMAC not detected, id=0x%x\n", id);
+               err = -ENODEV;
+               goto out;
+       }
+       dev_info(&pdev->dev, "ARC EMAC detected with id: 0x%x\n", id);
+
+       /* Get CPU clock frequency from device tree */
+       if (of_property_read_u32(pdev->dev.of_node, "clock-frequency",
+                                &clock_frequency)) {
+               dev_err(&pdev->dev, "failed to retrieve <clock-frequency> "
+                       "from device tree\n");
+               err = -EINVAL;
+               goto out;
+       }
+       priv->clock_frequency = clock_frequency;
+
+       /* Get IRQ from device tree */
+       err = of_irq_to_resource(pdev->dev.of_node, 0, &res_irq);
+       if (!err) {
+               dev_err(&pdev->dev, "failed to retrieve <irq> value "
+                       "from device tree\n");
+               err = -ENODEV;
+               goto out;
+       }
+       net_dev->irq = res_irq.start;
+       dev_info(&pdev->dev, "IRQ is %d\n", net_dev->irq);
+
+       /* Register interrupt handler for device */
+       err = devm_request_irq(&pdev->dev, net_dev->irq, arc_emac_intr, 0,
+                              net_dev->name, net_dev);
+       if (err) {
+               dev_err(&pdev->dev, "could not allocate IRQ\n");
+               goto out;
+       }
+
+       /* Get MAC address from device tree */
+       mac_addr = of_get_mac_address(pdev->dev.of_node);
+
+       if (!mac_addr || !is_valid_ether_addr(mac_addr))
+               eth_hw_addr_random(net_dev);
+       else
+               memcpy(net_dev->dev_addr, mac_addr, ETH_ALEN);
+
+       dev_info(&pdev->dev, "MAC address is now %pM\n", net_dev->dev_addr);
+
+       /* Allocate cache coherent memory for BD Rings - to avoid need to do
+        * explicit uncached ".di" accesses, which can potentially screw-up
+        */
+       priv->rxbd = (struct arc_emac_bd_t *)dmam_alloc_coherent(&pdev->dev,
+                                               RX_RING_SZ + TX_RING_SZ,
+                                        &priv->rxbd_dma_hdl, GFP_KERNEL);
+
+       if (!priv->rxbd) {
+               dev_err(&pdev->dev, "failed to allocate data buffers\n");
+               err = -ENOMEM;
+               goto out;
+       }
+
+       priv->txbd = priv->rxbd + RX_BD_NUM;
+
+       /* To keep things simple - we just do 1 big allocation, instead of 2
+        * separate ones for Rx and Tx Rings responsively
+        */
+       priv->txbd_dma_hdl = priv->rxbd_dma_hdl + RX_RING_SZ;
+       dev_dbg(&pdev->dev, "EMAC Device addr: Rx Ring [0x%x], Tx Ring[%x]\n",
+               (unsigned int)priv->rxbd_dma_hdl,
+               (unsigned int)priv->txbd_dma_hdl);
+
+       priv->mdio_priv = devm_kzalloc(&pdev->dev, sizeof(struct arc_mdio_priv),
+                                      GFP_KERNEL);
+
+       if (!priv->mdio_priv) {
+               dev_err(&pdev->dev, "cannot allocate memory for MDIO "
+                       "private structure\n");
+               err = -ENOMEM;
+               goto out;
+       }
+
+       priv->mdio_priv->reg_base_addr = priv->reg_base_addr;
+       priv->mdio_priv->dev = &pdev->dev;
+
+       err = arc_mdio_probe(pdev->dev.of_node, priv->mdio_priv);
+       if (err) {
+               dev_err(&pdev->dev, "failed to probe MII bus\n");
+               goto out;
+       }
+
+       netif_napi_add(net_dev, &priv->napi, arc_emac_poll, NAPI_WEIGHT);
+
+       err = register_netdev(net_dev);
+       if (err) {
+               netif_napi_del(&priv->napi);
+               dev_err(&pdev->dev, "failed to register network device\n");
+               goto out;
+       }
+
+       return 0;
+
+out:
+       free_netdev(net_dev);
+       return err;
+}
+
+static int arc_emac_remove(struct platform_device *pdev)
+{
+       struct net_device *net_dev = platform_get_drvdata(pdev);
+       struct arc_emac_priv *priv = netdev_priv(net_dev);
+
+       arc_mdio_remove(priv->mdio_priv);
+       unregister_netdev(net_dev);
+       netif_napi_del(&priv->napi);
+       free_netdev(net_dev);
+
+       return 0;
+}
+
+static const struct of_device_id arc_emac_dt_ids[] = {
+       { .compatible = "snps,arc-emac" },
+       { /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, arc_emac_dt_ids);
+
+static struct platform_driver arc_emac_driver = {
+               .probe = arc_emac_probe,
+               .remove = arc_emac_remove,
+               .driver = {
+                       .name = DRV_NAME,
+                       .owner = THIS_MODULE,
+                       .of_match_table  = arc_emac_dt_ids,
+                       },
+};
+
+module_platform_driver(arc_emac_driver);
+
+MODULE_AUTHOR("Alexey Brodkin <abrod...@synopsys.com>");
+MODULE_DESCRIPTION("ARC EMAC driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/net/ethernet/arc/arc_emac_mdio.c 
b/drivers/net/ethernet/arc/arc_emac_mdio.c
new file mode 100644
index 0000000..7d13dd5
--- /dev/null
+++ b/drivers/net/ethernet/arc/arc_emac_mdio.c
@@ -0,0 +1,170 @@
+/*
+ * Copyright (C) 2004, 2007-2010, 2011-2013 Synopsys, Inc. (www.synopsys.com)
+ *
+ * MDIO implementation for ARC EMAC
+ */
+
+#include <linux/delay.h>
+#include <linux/of_mdio.h>
+
+#include "arc_emac_regs.h"
+#include "arc_emac_mdio.h"
+
+/* Number of seconds we wait for "MDIO complete" flag to appear */
+#define ARC_MDIO_COMPLETE_POLL_COUNT   1
+
+/**
+ * arc_mdio_complete_wait - Waits until MDIO transaction is completed.
+ * @priv:      Pointer to ARC MDIO private data structure.
+ *
+ * returns:    0 on success, -ETIMEDOUT on a timeout.
+ */
+static int arc_mdio_complete_wait(struct arc_mdio_priv *priv)
+{
+       unsigned int status;
+       unsigned int count = (ARC_MDIO_COMPLETE_POLL_COUNT * 40);
+
+       while (1) {
+               /* Read STATUS register from EMAC */
+               status = EMAC_REG_GET(priv->reg_base_addr, R_STATUS);
+
+               /* Mask "MDIO complete" bit */
+               status &= MDIO_MASK;
+
+               if (status) {
+                       /* Reset "MDIO complete" flag */
+                       EMAC_REG_SET(priv->reg_base_addr, R_STATUS, status);
+                       break;
+               }
+
+               /* Make sure we never get into infinite loop */
+               if (count-- == 0) {
+                       WARN_ON(1);
+                       return -ETIMEDOUT;
+               }
+               msleep(25);
+       }
+       return 0;
+}
+
+/**
+ * arc_mdio_read - MDIO interface read function.
+ * @bus:       Pointer to MII bus structure.
+ * @phy_addr:  Address of the PHY device.
+ * @reg_num:   PHY register to read.
+ *
+ * returns:    The register contents on success, -ETIMEDOUT on a timeout.
+ *
+ * Reads the contents of the requested register from the requested PHY
+ * address.
+ */
+static int arc_mdio_read(struct mii_bus *bus, int phy_addr, int reg_num)
+{
+       int error;
+       unsigned int value;
+       struct arc_mdio_priv *priv = bus->priv;
+
+       EMAC_REG_SET(priv->reg_base_addr, R_MDIO,
+                    0x60020000 | (phy_addr << 23) | (reg_num << 18));
+
+       error = arc_mdio_complete_wait(priv);
+       if (error < 0)
+               return error;
+
+       value = EMAC_REG_GET(priv->reg_base_addr, R_MDIO) & 0xffff;
+
+       dev_dbg(priv->dev, "arc_mdio_read(phy_addr=%i, reg_num=%x) = %x\n",
+               phy_addr, reg_num, value);
+
+       return value;
+}
+
+/**
+ * arc_mdio_write - MDIO interface write function.
+ * @bus:       Pointer to MII bus structure.
+ * @phy_addr:  Address of the PHY device.
+ * @reg_num:   PHY register to write to.
+ * @value:     Value to be written into the register.
+ *
+ * returns:    0 on success, -ETIMEDOUT on a timeout.
+ *
+ * Writes the value to the requested register.
+ */
+static int arc_mdio_write(struct mii_bus *bus, int phy_addr,
+                         int reg_num, u16 value)
+{
+       struct arc_mdio_priv *priv = bus->priv;
+
+       dev_dbg(priv->dev,
+               "arc_mdio_write(phy_addr=%i, reg_num=%x, value=%x)\n",
+               phy_addr, reg_num, value);
+
+       EMAC_REG_SET(priv->reg_base_addr, R_MDIO,
+                    0x50020000 | (phy_addr << 23) | (reg_num << 18) |
+                    (value & 0xffff));
+
+       return arc_mdio_complete_wait(priv);
+}
+
+/**
+ * arc_mdio_probe - MDIO probe function.
+ * @dev_node:  Pointer to device node.
+ * @priv:      Pointer to ARC MDIO private data structure.
+ *
+ * returns:    0 on success, -ENOMEM when mdiobus_alloc
+ * (to allocate memory for MII bus structure) fails.
+ *
+ * Sets up and registers the MDIO interface.
+ */
+int arc_mdio_probe(struct device_node *dev_node, struct arc_mdio_priv *priv)
+{
+       struct mii_bus *bus;
+       int error;
+
+       bus = mdiobus_alloc();
+       if (!bus) {
+               error = -ENOMEM;
+               goto cleanup;
+       }
+
+       priv->bus = bus;
+       bus->priv = priv;
+       bus->name = "Synopsys MII Bus",
+       bus->read = &arc_mdio_read;
+       bus->write = &arc_mdio_write;
+
+       snprintf(bus->id, MII_BUS_ID_SIZE, "%.8x",
+                (unsigned int)priv->reg_base_addr);
+
+       bus->parent = priv->dev;
+
+       error = of_mdiobus_register(bus, dev_node);
+       if (error) {
+               dev_err(priv->dev, "cannot register %s as MDIO bus\n",
+                       bus->name);
+               goto cleanup;
+       }
+
+       return 0;
+
+cleanup:
+       if (bus)
+               mdiobus_free(bus);
+
+       return error;
+}
+
+/**
+ * arc_mdio_remove - MDIO remove function.
+ * @priv:      Pointer to ARC MDIO private data structure.
+ *
+ * Unregisters the MDIO and frees any associate memory for MII bus.
+ */
+int arc_mdio_remove(struct arc_mdio_priv *priv)
+{
+       mdiobus_unregister(priv->bus);
+       mdiobus_free(priv->bus);
+       priv->bus = NULL;
+
+       return 0;
+}
diff --git a/drivers/net/ethernet/arc/arc_emac_mdio.h 
b/drivers/net/ethernet/arc/arc_emac_mdio.h
new file mode 100644
index 0000000..954241e
--- /dev/null
+++ b/drivers/net/ethernet/arc/arc_emac_mdio.h
@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2004, 2007-2010, 2011-2013 Synopsys, Inc. (www.synopsys.com)
+ *
+ * Definitions for MDIO of ARC EMAC device driver
+ */
+
+#ifndef ARC_MDIO_H
+#define ARC_MDIO_H
+
+#include <linux/device.h>
+#include <linux/phy.h>
+
+struct arc_mdio_priv {
+       struct mii_bus *bus;
+       struct device *dev;
+       void __iomem *reg_base_addr; /* MAC registers base address */
+};
+
+int arc_mdio_probe(struct device_node *np, struct arc_mdio_priv *priv);
+int arc_mdio_remove(struct arc_mdio_priv *priv);
+
+#endif /* ARC_MDIO_H */
diff --git a/drivers/net/ethernet/arc/arc_emac_regs.h 
b/drivers/net/ethernet/arc/arc_emac_regs.h
new file mode 100644
index 0000000..e4c8d73
--- /dev/null
+++ b/drivers/net/ethernet/arc/arc_emac_regs.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2004, 2007-2010, 2011-2013 Synopsys, Inc. (www.synopsys.com)
+ *
+ * Registers and bits definitions of ARC EMAC
+ */
+
+#ifndef ARC_EMAC_REGS_H
+#define ARC_EMAC_REGS_H
+
+/* STATUS and ENABLE Register bit masks */
+#define TXINT_MASK     (1<<0)  /* Transmit interrupt */
+#define RXINT_MASK     (1<<1)  /* Receive interrupt */
+#define ERR_MASK       (1<<2)  /* Error interrupt */
+#define TXCH_MASK      (1<<3)  /* Transmit chaining error interrupt */
+#define MSER_MASK      (1<<4)  /* Missed packet counter error */
+#define RXCR_MASK      (1<<8)  /* RXCRCERR counter rolled over  */
+#define RXFR_MASK      (1<<9)  /* RXFRAMEERR counter rolled over */
+#define RXFL_MASK      (1<<10) /* RXOFLOWERR counter rolled over */
+#define MDIO_MASK      (1<<12) /* MDIO complete interrupt */
+#define TXPL_MASK      (1<<31) /* TXPOLL */
+
+/* CONTROL Register bit masks */
+#define EN_MASK                (1<<0)  /* VMAC enable */
+#define TXRN_MASK      (1<<3)  /* TX enable */
+#define RXRN_MASK      (1<<4)  /* RX enable */
+#define DSBC_MASK      (1<<8)  /* Disable receive broadcast */
+#define ENFL_MASK      (1<<10) /* Enable Full-duplex */
+#define PROM_MASK      (1<<11) /* Promiscuous mode */
+
+/* Buffer descriptor INFO bit masks */
+#define OWN_MASK       (1<<31) /* 0-CPU owns buffer, 1-EMAC owns buffer */
+#define FRST_MASK      (1<<16) /* First buffer in chain */
+#define LAST_MASK      (1<<17) /* Last buffer in chain */
+#define LEN_MASK       0x000007FF      /* last 11 bits */
+#define CRLS           (1<<21)
+#define DEFR           (1<<22)
+#define DROP           (1<<23)
+#define RTRY           (1<<24)
+#define LTCL           (1<<28)
+#define UFLO           (1<<29)
+
+#define FOR_EMAC       OWN_MASK
+#define FOR_CPU                0
+
+/* ARC EMAC register set combines entries for MAC and MDIO */
+enum {
+       R_ID = 0,
+       R_STATUS,
+       R_ENABLE,
+       R_CTRL,
+       R_POLLRATE,
+       R_RXERR,
+       R_MISS,
+       R_TX_RING,
+       R_RX_RING,
+       R_ADDRL,
+       R_ADDRH,
+       R_LAFL,
+       R_LAFH,
+       R_MDIO,
+};
+
+#define EMAC_REG_SET(reg_base_addr, reg, val)  \
+                       iowrite32((val), reg_base_addr + reg * sizeof(int))
+
+#define EMAC_REG_GET(reg_base_addr, reg)       \
+                       ioread32(reg_base_addr + reg * sizeof(int))
+
+#define EMAC_REG_OR(b, r, v)  EMAC_REG_SET(b, r, EMAC_REG_GET(b, r) | (v))
+#define EMAC_REG_CLR(b, r, v) EMAC_REG_SET(b, r, EMAC_REG_GET(b, r) & ~(v))
+
+#endif /* ARC_EMAC_REGS_H */
-- 
1.7.10.4

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