Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

Pull networking updates from David Miller:
 "This is a re-do of the net-next pull request for the current merge
  window.  The only difference from the one I made the other day is that
  this has Eliezer's interface renames and the timeout handling changes
  made based upon your feedback, as well as a few bug fixes that have
  trickeled in.

  Highlights:

   1) Low latency device polling, eliminating the cost of interrupt
      handling and context switches.  Allows direct polling of a network
      device from socket operations, such as recvmsg() and poll().

      Currently ixgbe, mlx4, and bnx2x support this feature.

      Full high level description, performance numbers, and design in
      commit 0a4db187a999 ("Merge branch 'll_poll'")

      From Eliezer Tamir.

   2) With the routing cache removed, ip_check_mc_rcu() gets exercised
      more than ever before in the case where we have lots of multicast
      addresses.  Use a hash table instead of a simple linked list, from
      Eric Dumazet.

   3) Add driver for Atheros CQA98xx 802.11ac wireless devices, from
      Bartosz Markowski, Janusz Dziedzic, Kalle Valo, Marek Kwaczynski,
      Marek Puzyniak, Michal Kazior, and Sujith Manoharan.

   4) Support reporting the TUN device persist flag to userspace, from
      Pavel Emelyanov.

   5) Allow controlling network device VF link state using netlink, from
      Rony Efraim.

   6) Support GRE tunneling in openvswitch, from Pravin B Shelar.

   7) Adjust SOCK_MIN_RCVBUF and SOCK_MIN_SNDBUF for modern times, from
      Daniel Borkmann and Eric Dumazet.

   8) Allow controlling of TCP quickack behavior on a per-route basis,
      from Cong Wang.

   9) Several bug fixes and improvements to vxlan from Stephen
      Hemminger, Pravin B Shelar, and Mike Rapoport.  In particular,
      support receiving on multiple UDP ports.

  10) Major cleanups, particular in the area of debugging and cookie
      lifetime handline, to the SCTP protocol code.  From Daniel
      Borkmann.

  11) Allow packets to cross network namespaces when traversing tunnel
      devices.  From Nicolas Dichtel.

  12) Allow monitoring netlink traffic via AF_PACKET sockets, in a
      manner akin to how we monitor real network traffic via ptype_all.
      From Daniel Borkmann.

  13) Several bug fixes and improvements for the new alx device driver,
      from Johannes Berg.

  14) Fix scalability issues in the netem packet scheduler's time queue,
      by using an rbtree.  From Eric Dumazet.

  15) Several bug fixes in TCP loss recovery handling, from Yuchung
      Cheng.

  16) Add support for GSO segmentation of MPLS packets, from Simon
      Horman.

  17) Make network notifiers have a real data type for the opaque
      pointer that's passed into them.  Use this to properly handle
      network device flag changes in arp_netdev_event().  From Jiri
      Pirko and Timo Teräs.

  18) Convert several drivers over to module_pci_driver(), from Peter
      Huewe.

  19) tcp_fixup_rcvbuf() can loop 500 times over loopback, just use a
      O(1) calculation instead.  From Eric Dumazet.

  20) Support setting of explicit tunnel peer addresses in ipv6, just
      like ipv4.  From Nicolas Dichtel.

  21) Protect x86 BPF JIT against spraying attacks, from Eric Dumazet.

  22) Prevent a single high rate flow from overruning an individual cpu
      during RX packet processing via selective flow shedding.  From
      Willem de Bruijn.

  23) Don't use spinlocks in TCP md5 signing fast paths, from Eric
      Dumazet.

  24) Don't just drop GSO packets which are above the TBF scheduler's
      burst limit, chop them up so they are in-bounds instead.  Also
      from Eric Dumazet.

  25) VLAN offloads are missed when configured on top of a bridge, fix
      from Vlad Yasevich.

  26) Support IPV6 in ping sockets.  From Lorenzo Colitti.

  27) Receive flow steering targets should be updated at poll() time
      too, from David Majnemer.

  28) Fix several corner case regressions in PMTU/redirect handling due
      to the routing cache removal, from Timo Teräs.

  29) We have to be mindful of ipv4 mapped ipv6 sockets in
      upd_v6_push_pending_frames().  From Hannes Frederic Sowa.

  30) Fix L2TP sequence number handling bugs, from James Chapman."

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1214 commits)
  drivers/net: caif: fix wrong rtnl_is_locked() usage
  drivers/net: enic: release rtnl_lock on error-path
  vhost-net: fix use-after-free in vhost_net_flush
  net: mv643xx_eth: do not use port number as platform device id
  net: sctp: confirm route during forward progress
  virtio_net: fix race in RX VQ processing
  virtio: support unlocked queue poll
  net/cadence/macb: fix bug/typo in extracting gem_irq_read_clear bit
  Documentation: Fix references to defunct linux-net@vger.kernel.org
  net/fs: change busy poll time accounting
  net: rename low latency sockets functions to busy poll
  bridge: fix some kernel warning in multicast timer
  sfc: Fix memory leak when discarding scattered packets
  sit: fix tunnel update via netlink
  dt:net:stmmac: Add dt specific phy reset callback support.
  dt:net:stmmac: Add support to dwmac version 3.610 and 3.710
  dt:net:stmmac: Allocate platform data only if its NULL.
  net:stmmac: fix memleak in the open method
  ipv6: rt6_check_neigh should successfully verify neigh if no NUD information are available
  net: ipv6: fix wrong ping_v6_sendmsg return value
  ...

1 files changed, 819 insertions, 0 deletions

diff --git a/drivers/net/ethernet/arc/emac_main.c b/drivers/net/ethernet/arc/emac_main.c
new file mode 100644
index 00000000000..f1b121ee552
--- /dev/null
+++ b/drivers/net/ethernet/arc/emac_main.c
@@ -0,0 +1,819 @@
+/*
+ * Copyright (C) 2004-2013 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 (hardware revision 5)
+ *
+ * Contributors:
+ *		Amit Bhor
+ *		Sameer Dhavale
+ *		Vineet Gupta
+ */
+
+#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 "emac.h"
+
+#define DRV_NAME	"arc_emac"
+#define DRV_VERSION	"1.0"
+
+/**
+ * arc_emac_adjust_link - Adjust the PHY link duplex.
+ * @ndev:	Pointer to the net_device structure.
+ *
+ * This function is called to change the duplex setting after auto negotiation
+ * is done by the PHY.
+ */
+static void arc_emac_adjust_link(struct net_device *ndev)
+{
+	struct arc_emac_priv *priv = netdev_priv(ndev);
+	struct phy_device *phy_dev = priv->phy_dev;
+	unsigned int reg, state_changed = 0;
+
+	if (priv->link != phy_dev->link) {
+		priv->link = phy_dev->link;
+		state_changed = 1;
+	}
+
+	if (priv->speed != phy_dev->speed) {
+		priv->speed = phy_dev->speed;
+		state_changed = 1;
+	}
+
+	if (priv->duplex != phy_dev->duplex) {
+		reg = arc_reg_get(priv, R_CTRL);
+
+		if (DUPLEX_FULL == phy_dev->duplex)
+			reg |= ENFL_MASK;
+		else
+			reg &= ~ENFL_MASK;
+
+		arc_reg_set(priv, R_CTRL, reg);
+		priv->duplex = phy_dev->duplex;
+		state_changed = 1;
+	}
+
+	if (state_changed)
+		phy_print_status(phy_dev);
+}
+
+/**
+ * arc_emac_get_settings - Get PHY settings.
+ * @ndev:	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 *ndev,
+				 struct ethtool_cmd *cmd)
+{
+	struct arc_emac_priv *priv = netdev_priv(ndev);
+
+	return phy_ethtool_gset(priv->phy_dev, cmd);
+}
+
+/**
+ * arc_emac_set_settings - Set PHY settings as passed in the argument.
+ * @ndev:	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 *ndev,
+				 struct ethtool_cmd *cmd)
+{
+	struct arc_emac_priv *priv = netdev_priv(ndev);
+
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
+	return phy_ethtool_sset(priv->phy_dev, cmd);
+}
+
+/**
+ * arc_emac_get_drvinfo - Get EMAC driver information.
+ * @ndev:	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 *ndev,
+				 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,
+};
+
+#define FIRST_OR_LAST_MASK	(FIRST_MASK | LAST_MASK)
+
+/**
+ * arc_emac_tx_clean - clears processed by EMAC Tx BDs.
+ * @ndev:	Pointer to the network device.
+ */
+static void arc_emac_tx_clean(struct net_device *ndev)
+{
+	struct arc_emac_priv *priv = netdev_priv(ndev);
+	struct net_device_stats *stats = &priv->stats;
+	unsigned int i;
+
+	for (i = 0; i < TX_BD_NUM; i++) {
+		unsigned int *txbd_dirty = &priv->txbd_dirty;
+		struct arc_emac_bd *txbd = &priv->txbd[*txbd_dirty];
+		struct buffer_state *tx_buff = &priv->tx_buff[*txbd_dirty];
+		struct sk_buff *skb = tx_buff->skb;
+		unsigned int info = le32_to_cpu(txbd->info);
+
+		*txbd_dirty = (*txbd_dirty + 1) % TX_BD_NUM;
+
+		if ((info & FOR_EMAC) || !txbd->data)
+			break;
+
+		if (unlikely(info & (DROP | DEFR | LTCL | UFLO))) {
+			stats->tx_errors++;
+			stats->tx_dropped++;
+
+			if (info & DEFR)
+				stats->tx_carrier_errors++;
+
+			if (info & LTCL)
+				stats->collisions++;
+
+			if (info & UFLO)
+				stats->tx_fifo_errors++;
+		} else if (likely(info & FIRST_OR_LAST_MASK)) {
+			stats->tx_packets++;
+			stats->tx_bytes += skb->len;
+		}
+
+		dma_unmap_single(&ndev->dev, dma_unmap_addr(tx_buff, addr),
+				 dma_unmap_len(tx_buff, len), DMA_TO_DEVICE);
+
+		/* return the sk_buff to system */
+		dev_kfree_skb_irq(skb);
+
+		txbd->data = 0;
+		txbd->info = 0;
+
+		if (netif_queue_stopped(ndev))
+			netif_wake_queue(ndev);
+	}
+}
+
+/**
+ * arc_emac_rx - processing of Rx packets.
+ * @ndev:	Pointer to the network device.
+ * @budget:	How many BDs to process on 1 call.
+ *
+ * returns:	Number of processed BDs
+ *
+ * Iterate through Rx BDs and deliver received packages to upper layer.
+ */
+static int arc_emac_rx(struct net_device *ndev, int budget)
+{
+	struct arc_emac_priv *priv = netdev_priv(ndev);
+	unsigned int work_done;
+
+	for (work_done = 0; work_done <= budget; work_done++) {
+		unsigned int *last_rx_bd = &priv->last_rx_bd;
+		struct net_device_stats *stats = &priv->stats;
+		struct buffer_state *rx_buff = &priv->rx_buff[*last_rx_bd];
+		struct arc_emac_bd *rxbd = &priv->rxbd[*last_rx_bd];
+		unsigned int pktlen, info = le32_to_cpu(rxbd->info);
+		struct sk_buff *skb;
+		dma_addr_t addr;
+
+		if (unlikely((info & OWN_MASK) == FOR_EMAC))
+			break;
+
+		/* Make a note that we saw a packet at this BD.
+		 * So next time, driver starts from this + 1
+		 */
+		*last_rx_bd = (*last_rx_bd + 1) % RX_BD_NUM;
+
+		if (unlikely((info & FIRST_OR_LAST_MASK) !=
+			     FIRST_OR_LAST_MASK)) {
+			/* We pre-allocate buffers of MTU size so incoming
+			 * packets won't be split/chained.
+			 */
+			if (net_ratelimit())
+				netdev_err(ndev, "incomplete packet received\n");
+
+			/* Return ownership to EMAC */
+			rxbd->info = cpu_to_le32(FOR_EMAC | EMAC_BUFFER_SIZE);
+			stats->rx_errors++;
+			stats->rx_length_errors++;
+			continue;
+		}
+
+		pktlen = info & LEN_MASK;
+		stats->rx_packets++;
+		stats->rx_bytes += pktlen;
+		skb = rx_buff->skb;
+		skb_put(skb, pktlen);
+		skb->dev = ndev;
+		skb->protocol = eth_type_trans(skb, ndev);
+
+		dma_unmap_single(&ndev->dev, dma_unmap_addr(rx_buff, addr),
+				 dma_unmap_len(rx_buff, len), DMA_FROM_DEVICE);
+
+		/* Prepare the BD for next cycle */
+		rx_buff->skb = netdev_alloc_skb_ip_align(ndev,
+							 EMAC_BUFFER_SIZE);
+		if (unlikely(!rx_buff->skb)) {
+			stats->rx_errors++;
+			/* Because receive_skb is below, increment rx_dropped */
+			stats->rx_dropped++;
+			continue;
+		}
+
+		/* receive_skb only if new skb was allocated to avoid holes */
+		netif_receive_skb(skb);
+
+		addr = dma_map_single(&ndev->dev, (void *)rx_buff->skb->data,
+				      EMAC_BUFFER_SIZE, DMA_FROM_DEVICE);
+		if (dma_mapping_error(&ndev->dev, addr)) {
+			if (net_ratelimit())
+				netdev_err(ndev, "cannot dma map\n");
+			dev_kfree_skb(rx_buff->skb);
+			stats->rx_errors++;
+			continue;
+		}
+		dma_unmap_addr_set(rx_buff, addr, addr);
+		dma_unmap_len_set(rx_buff, len, EMAC_BUFFER_SIZE);
+
+		rxbd->data = cpu_to_le32(addr);
+
+		/* Make sure pointer to data buffer is set */
+		wmb();
+
+		/* Return ownership to EMAC */
+		rxbd->info = cpu_to_le32(FOR_EMAC | EMAC_BUFFER_SIZE);
+	}
+
+	return work_done;
+}
+
+/**
+ * arc_emac_poll - NAPI poll handler.
+ * @napi:	Pointer to napi_struct structure.
+ * @budget:	How many BDs to process on 1 call.
+ *
+ * returns:	Number of processed BDs
+ */
+static int arc_emac_poll(struct napi_struct *napi, int budget)
+{
+	struct net_device *ndev = napi->dev;
+	struct arc_emac_priv *priv = netdev_priv(ndev);
+	unsigned int work_done;
+
+	arc_emac_tx_clean(ndev);
+
+	work_done = arc_emac_rx(ndev, budget);
+	if (work_done < budget) {
+		napi_complete(napi);
+		arc_reg_or(priv, R_ENABLE, RXINT_MASK);
+	}
+
+	return work_done;
+}
+
+/**
+ * arc_emac_intr - Global interrupt handler for EMAC.
+ * @irq:		irq number.
+ * @dev_instance:	device instance.
+ *
+ * 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 *ndev = dev_instance;
+	struct arc_emac_priv *priv = netdev_priv(ndev);
+	struct net_device_stats *stats = &priv->stats;
+	unsigned int status;
+
+	status = arc_reg_get(priv, R_STATUS);
+	status &= ~MDIO_MASK;
+
+	/* Reset all flags except "MDIO complete" */
+	arc_reg_set(priv, R_STATUS, status);
+
+	if (status & RXINT_MASK) {
+		if (likely(napi_schedule_prep(&priv->napi))) {
+			arc_reg_clr(priv, R_ENABLE, RXINT_MASK);
+			__napi_schedule(&priv->napi);
+		}
+	}
+
+	if (status & ERR_MASK) {
+		/* MSER/RXCR/RXFR/RXFL interrupt fires on corresponding
+		 * 8-bit error counter overrun.
+		 */
+
+		if (status & MSER_MASK) {
+			stats->rx_missed_errors += 0x100;
+			stats->rx_errors += 0x100;
+		}
+
+		if (status & RXCR_MASK) {
+			stats->rx_crc_errors += 0x100;
+			stats->rx_errors += 0x100;
+		}
+
+		if (status & RXFR_MASK) {
+			stats->rx_frame_errors += 0x100;
+			stats->rx_errors += 0x100;
+		}
+
+		if (status & RXFL_MASK) {
+			stats->rx_over_errors += 0x100;
+			stats->rx_errors += 0x100;
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * arc_emac_open - Open the network device.
+ * @ndev:	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.
+ */
+static int arc_emac_open(struct net_device *ndev)
+{
+	struct arc_emac_priv *priv = netdev_priv(ndev);
+	struct phy_device *phy_dev = priv->phy_dev;
+	int i;
+
+	phy_dev->autoneg = AUTONEG_ENABLE;
+	phy_dev->speed = 0;
+	phy_dev->duplex = 0;
+	phy_dev->advertising = phy_dev->supported;
+
+	if (priv->max_speed > 100) {
+		phy_dev->advertising &= PHY_GBIT_FEATURES;
+	} else if (priv->max_speed <= 100) {
+		phy_dev->advertising &= PHY_BASIC_FEATURES;
+		if (priv->max_speed <= 10) {
+			phy_dev->advertising &= ~SUPPORTED_100baseT_Half;
+			phy_dev->advertising &= ~SUPPORTED_100baseT_Full;
+		}
+	}
+
+	priv->last_rx_bd = 0;
+
+	/* Allocate and set buffers for Rx BD's */
+	for (i = 0; i < RX_BD_NUM; i++) {
+		dma_addr_t addr;
+		unsigned int *last_rx_bd = &priv->last_rx_bd;
+		struct arc_emac_bd *rxbd = &priv->rxbd[*last_rx_bd];
+		struct buffer_state *rx_buff = &priv->rx_buff[*last_rx_bd];
+
+		rx_buff->skb = netdev_alloc_skb_ip_align(ndev,
+							 EMAC_BUFFER_SIZE);
+		if (unlikely(!rx_buff->skb))
+			return -ENOMEM;
+
+		addr = dma_map_single(&ndev->dev, (void *)rx_buff->skb->data,
+				      EMAC_BUFFER_SIZE, DMA_FROM_DEVICE);
+		if (dma_mapping_error(&ndev->dev, addr)) {
+			netdev_err(ndev, "cannot dma map\n");
+			dev_kfree_skb(rx_buff->skb);
+			return -ENOMEM;
+		}
+		dma_unmap_addr_set(rx_buff, addr, addr);
+		dma_unmap_len_set(rx_buff, len, EMAC_BUFFER_SIZE);
+
+		rxbd->data = cpu_to_le32(addr);
+
+		/* Make sure pointer to data buffer is set */
+		wmb();
+
+		/* Return ownership to EMAC */
+		rxbd->info = cpu_to_le32(FOR_EMAC | EMAC_BUFFER_SIZE);
+
+		*last_rx_bd = (*last_rx_bd + 1) % RX_BD_NUM;
+	}
+
+	/* Clean Tx BD's */
+	memset(priv->txbd, 0, TX_RING_SZ);
+
+	/* Initialize logical address filter */
+	arc_reg_set(priv, R_LAFL, 0);
+	arc_reg_set(priv, R_LAFH, 0);
+
+	/* Set BD ring pointers for device side */
+	arc_reg_set(priv, R_RX_RING, (unsigned int)priv->rxbd_dma);
+	arc_reg_set(priv, R_TX_RING, (unsigned int)priv->txbd_dma);
+
+	/* Enable interrupts */
+	arc_reg_set(priv, R_ENABLE, RXINT_MASK | ERR_MASK);
+
+	/* Set CONTROL */
+	arc_reg_set(priv, R_CTRL,
+		     (RX_BD_NUM << 24) |	/* RX BD table length */
+		     (TX_BD_NUM << 16) |	/* TX BD table length */
+		     TXRN_MASK | RXRN_MASK);
+
+	napi_enable(&priv->napi);
+
+	/* Enable EMAC */
+	arc_reg_or(priv, R_CTRL, EN_MASK);
+
+	phy_start_aneg(priv->phy_dev);
+
+	netif_start_queue(ndev);
+
+	return 0;
+}
+
+/**
+ * arc_emac_stop - Close the network device.
+ * @ndev:	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.
+ */
+static int arc_emac_stop(struct net_device *ndev)
+{
+	struct arc_emac_priv *priv = netdev_priv(ndev);
+
+	napi_disable(&priv->napi);
+	netif_stop_queue(ndev);
+
+	/* Disable interrupts */
+	arc_reg_clr(priv, R_ENABLE, RXINT_MASK | ERR_MASK);
+
+	/* Disable EMAC */
+	arc_reg_clr(priv, R_CTRL, EN_MASK);
+
+	return 0;
+}
+
+/**
+ * arc_emac_stats - Get system network statistics.
+ * @ndev:	Pointer to net_device structure.
+ *
+ * Returns the address of the device statistics structure.
+ * Statistics are updated in interrupt handler.
+ */
+static struct net_device_stats *arc_emac_stats(struct net_device *ndev)
+{
+	struct arc_emac_priv *priv = netdev_priv(ndev);
+	struct net_device_stats *stats = &priv->stats;
+	unsigned long miss, rxerr;
+	u8 rxcrc, rxfram, rxoflow;
+
+	rxerr = arc_reg_get(priv, R_RXERR);
+	miss = arc_reg_get(priv, R_MISS);
+
+	rxcrc = rxerr;
+	rxfram = rxerr >> 8;
+	rxoflow = rxerr >> 16;
+
+	stats->rx_errors += miss;
+	stats->rx_errors += rxcrc + rxfram + rxoflow;
+
+	stats->rx_over_errors += rxoflow;
+	stats->rx_frame_errors += rxfram;
+	stats->rx_crc_errors += rxcrc;
+	stats->rx_missed_errors += miss;
+
+	return stats;
+}
+
+/**
+ * arc_emac_tx - Starts the data transmission.
+ * @skb:	sk_buff pointer that contains data to be Transmitted.
+ * @ndev:	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.
+ */
+static int arc_emac_tx(struct sk_buff *skb, struct net_device *ndev)
+{
+	struct arc_emac_priv *priv = netdev_priv(ndev);
+	unsigned int len, *txbd_curr = &priv->txbd_curr;
+	struct net_device_stats *stats = &priv->stats;
+	__le32 *info = &priv->txbd[*txbd_curr].info;
+	dma_addr_t addr;
+
+	if (skb_padto(skb, ETH_ZLEN))
+		return NETDEV_TX_OK;
+
+	len = max_t(unsigned int, ETH_ZLEN, skb->len);
+
+	/* EMAC still holds this buffer in its possession.
+	 * CPU must not modify this buffer descriptor
+	 */
+	if (unlikely((le32_to_cpu(*info) & OWN_MASK) == FOR_EMAC)) {
+		netif_stop_queue(ndev);
+		return NETDEV_TX_BUSY;
+	}
+
+	addr = dma_map_single(&ndev->dev, (void *)skb->data, len,
+			      DMA_TO_DEVICE);
+
+	if (unlikely(dma_mapping_error(&ndev->dev, addr))) {
+		stats->tx_dropped++;
+		stats->tx_errors++;
+		dev_kfree_skb(skb);
+		return NETDEV_TX_OK;
+	}
+	dma_unmap_addr_set(&priv->tx_buff[*txbd_curr], addr, addr);
+	dma_unmap_len_set(&priv->tx_buff[*txbd_curr], len, len);
+
+	priv->tx_buff[*txbd_curr].skb = skb;
+	priv->txbd[*txbd_curr].data = cpu_to_le32(addr);
+
+	/* Make sure pointer to data buffer is set */
+	wmb();
+
+	*info = cpu_to_le32(FOR_EMAC | FIRST_OR_LAST_MASK | len);
+
+	/* Increment index to point to the next BD */
+	*txbd_curr = (*txbd_curr + 1) % TX_BD_NUM;
+
+	/* Get "info" of the next BD */
+	info = &priv->txbd[*txbd_curr].info;
+
+	/* Check if if Tx BD ring is full - next BD is still owned by EMAC */
+	if (unlikely((le32_to_cpu(*info) & OWN_MASK) == FOR_EMAC))
+		netif_stop_queue(ndev);
+
+	arc_reg_set(priv, R_STATUS, TXPL_MASK);
+
+	skb_tx_timestamp(skb);
+
+	return NETDEV_TX_OK;
+}
+
+/**
+ * arc_emac_set_address - Set the MAC address for this device.
+ * @ndev:	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.
+ */
+static int arc_emac_set_address(struct net_device *ndev, void *p)
+{
+	struct arc_emac_priv *priv = netdev_priv(ndev);
+	struct sockaddr *addr = p;
+	unsigned int addr_low, addr_hi;
+
+	if (netif_running(ndev))
+		return -EBUSY;
+
+	if (!is_valid_ether_addr(addr->sa_data))
+		return -EADDRNOTAVAIL;
+
+	memcpy(ndev->dev_addr, addr->sa_data, ndev->addr_len);
+
+	addr_low = le32_to_cpu(*(__le32 *) &ndev->dev_addr[0]);
+	addr_hi = le16_to_cpu(*(__le16 *) &ndev->dev_addr[4]);
+
+	arc_reg_set(priv, R_ADDRL, addr_low);
+	arc_reg_set(priv, R_ADDRH, addr_hi);
+
+	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 resource res_regs, res_irq;
+	struct device_node *phy_node;
+	struct arc_emac_priv *priv;
+	struct net_device *ndev;
+	const char *mac_addr;
+	unsigned int id, clock_frequency;
+	int err;
+
+	if (!pdev->dev.of_node)
+		return -ENODEV;
+
+	/* Get PHY from device tree */
+	phy_node = of_parse_phandle(pdev->dev.of_node, "phy", 0);
+	if (!phy_node) {
+		dev_err(&pdev->dev, "failed to retrieve phy description from device tree\n");
+		return -ENODEV;
+	}
+
+	/* 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");
+		return -ENODEV;
+	}
+
+	/* 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");
+		return -EINVAL;
+	}
+
+	/* 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");
+		return -ENODEV;
+	}
+
+	ndev = alloc_etherdev(sizeof(struct arc_emac_priv));
+	if (!ndev)
+		return -ENOMEM;
+
+	SET_NETDEV_DEV(ndev, &pdev->dev);
+
+	ndev->netdev_ops = &arc_emac_netdev_ops;
+	ndev->ethtool_ops = &arc_emac_ethtool_ops;
+	ndev->watchdog_timeo = TX_TIMEOUT;
+	/* FIXME :: no multicast support yet */
+	ndev->flags &= ~IFF_MULTICAST;
+
+	priv = netdev_priv(ndev);
+	priv->dev = &pdev->dev;
+	priv->ndev = ndev;
+
+	priv->regs = devm_ioremap_resource(&pdev->dev, &res_regs);
+	if (IS_ERR(priv->regs)) {
+		err = PTR_ERR(priv->regs);
+		goto out;
+	}
+	dev_dbg(&pdev->dev, "Registers base address is 0x%p\n", priv->regs);
+
+	id = arc_reg_get(priv, 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);
+
+	/* Set poll rate so that it polls every 1 ms */
+	arc_reg_set(priv, R_POLLRATE, clock_frequency / 1000000);
+
+	/* Get max speed of operation from device tree */
+	if (of_property_read_u32(pdev->dev.of_node, "max-speed",
+				 &priv->max_speed)) {
+		dev_err(&pdev->dev, "failed to retrieve <max-speed> from device tree\n");
+		err = -EINVAL;
+		goto out;
+	}
+
+	ndev->irq = res_irq.start;
+	dev_info(&pdev->dev, "IRQ is %d\n", ndev->irq);
+
+	/* Register interrupt handler for device */
+	err = devm_request_irq(&pdev->dev, ndev->irq, arc_emac_intr, 0,
+			       ndev->name, ndev);
+	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(ndev);
+	else
+		memcpy(ndev->dev_addr, mac_addr, ETH_ALEN);
+
+	dev_info(&pdev->dev, "MAC address is now %pM\n", ndev->dev_addr);
+
+	/* Do 1 allocation instead of 2 separate ones for Rx and Tx BD rings */
+	priv->rxbd = dmam_alloc_coherent(&pdev->dev, RX_RING_SZ + TX_RING_SZ,
+					 &priv->rxbd_dma, 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;
+
+	priv->txbd_dma = priv->rxbd_dma + RX_RING_SZ;
+	dev_dbg(&pdev->dev, "EMAC Device addr: Rx Ring [0x%x], Tx Ring[%x]\n",
+		(unsigned int)priv->rxbd_dma, (unsigned int)priv->txbd_dma);
+
+	err = arc_mdio_probe(pdev, priv);
+	if (err) {
+		dev_err(&pdev->dev, "failed to probe MII bus\n");
+		goto out;
+	}
+
+	priv->phy_dev = of_phy_connect(ndev, phy_node, arc_emac_adjust_link, 0,
+				       PHY_INTERFACE_MODE_MII);
+	if (!priv->phy_dev) {
+		dev_err(&pdev->dev, "of_phy_connect() failed\n");
+		err = -ENODEV;
+		goto out;
+	}
+
+	dev_info(&pdev->dev, "connected to %s phy with id 0x%x\n",
+		 priv->phy_dev->drv->name, priv->phy_dev->phy_id);
+
+	netif_napi_add(ndev, &priv->napi, arc_emac_poll, ARC_EMAC_NAPI_WEIGHT);
+
+	err = register_netdev(ndev);
+	if (err) {
+		netif_napi_del(&priv->napi);
+		dev_err(&pdev->dev, "failed to register network device\n");
+		goto out;
+	}
+
+	return 0;
+
+out:
+	free_netdev(ndev);
+	return err;
+}
+
+static int arc_emac_remove(struct platform_device *pdev)
+{
+	struct net_device *ndev = platform_get_drvdata(pdev);
+	struct arc_emac_priv *priv = netdev_priv(ndev);
+
+	phy_disconnect(priv->phy_dev);
+	priv->phy_dev = NULL;
+	arc_mdio_remove(priv);
+	unregister_netdev(ndev);
+	netif_napi_del(&priv->napi);
+	free_netdev(ndev);
+
+	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 <abrodkin@synopsys.com>");
+MODULE_DESCRIPTION("ARC EMAC driver");
+MODULE_LICENSE("GPL");