net: ethernet: add driver for Aurora VLSI NB8800 Ethernet controller

This adds a driver for the Aurora VLSI NB8800 Ethernet controller.
It is an almost complete rewrite of a driver originally found in
a Sigma Designs 2.6.22 tree.
Signed-off-by: Mans Rullgard <mans@mansr.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/Kconfig

@@ -29,6 +29,7 @@ source "drivers/net/ethernet/apm/Kconfig"
 source "drivers/net/ethernet/apple/Kconfig"
 source "drivers/net/ethernet/arc/Kconfig"
 source "drivers/net/ethernet/atheros/Kconfig"
+source "drivers/net/ethernet/aurora/Kconfig"
 source "drivers/net/ethernet/cadence/Kconfig"
 source "drivers/net/ethernet/adi/Kconfig"
 source "drivers/net/ethernet/broadcom/Kconfig"

drivers/net/ethernet/Makefile

@@ -15,6 +15,7 @@ obj-$(CONFIG_NET_XGENE) += apm/
 obj-$(CONFIG_NET_VENDOR_APPLE) += apple/
 obj-$(CONFIG_NET_VENDOR_ARC) += arc/
 obj-$(CONFIG_NET_VENDOR_ATHEROS) += atheros/
+obj-$(CONFIG_NET_VENDOR_AURORA) += aurora/
 obj-$(CONFIG_NET_CADENCE) += cadence/
 obj-$(CONFIG_NET_BFIN) += adi/
 obj-$(CONFIG_NET_VENDOR_BROADCOM) += broadcom/

drivers/net/ethernet/aurora/Kconfig

+config NET_VENDOR_AURORA
+	bool "Aurora VLSI devices"
+	help
+	  If you have a network (Ethernet) device belonging to this class,
+	  say Y.
+
+	  Note that the answer to this question doesn't directly affect the
+	  kernel: saying N will just cause the configurator to skip all
+	  questions about Aurora devices. If you say Y, you will be asked
+	  for your specific device in the following questions.
+
+if NET_VENDOR_AURORA
+
+config AURORA_NB8800
+	tristate "Aurora AU-NB8800 support"
+	select PHYLIB
+	help
+	 Support for the AU-NB8800 gigabit Ethernet controller.
+
+endif

drivers/net/ethernet/aurora/Makefile

+obj-$(CONFIG_AURORA_NB8800) += nb8800.o

drivers/net/ethernet/aurora/nb8800.c

+/*
+ * Copyright (C) 2015 Mans Rullgard <mans@mansr.com>
+ *
+ * Mostly rewritten, based on driver from Sigma Designs.  Original
+ * copyright notice below.
+ *
+ *
+ * Driver for tangox SMP864x/SMP865x/SMP867x/SMP868x builtin Ethernet Mac.
+ *
+ * Copyright (C) 2005 Maxime Bizon <mbizon@freebox.fr>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/etherdevice.h>
+#include <linux/delay.h>
+#include <linux/ethtool.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/of_device.h>
+#include <linux/of_mdio.h>
+#include <linux/of_net.h>
+#include <linux/dma-mapping.h>
+#include <linux/phy.h>
+#include <linux/cache.h>
+#include <linux/jiffies.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <asm/barrier.h>
+
+#include "nb8800.h"
+
+static void nb8800_tx_done(struct net_device *dev);
+static int nb8800_dma_stop(struct net_device *dev);
+
+static inline u8 nb8800_readb(struct nb8800_priv *priv, int reg)
+{
+	return readb_relaxed(priv->base + reg);
+}
+
+static inline u32 nb8800_readl(struct nb8800_priv *priv, int reg)
+{
+	return readl_relaxed(priv->base + reg);
+}
+
+static inline void nb8800_writeb(struct nb8800_priv *priv, int reg, u8 val)
+{
+	writeb_relaxed(val, priv->base + reg);
+}
+
+static inline void nb8800_writew(struct nb8800_priv *priv, int reg, u16 val)
+{
+	writew_relaxed(val, priv->base + reg);
+}
+
+static inline void nb8800_writel(struct nb8800_priv *priv, int reg, u32 val)
+{
+	writel_relaxed(val, priv->base + reg);
+}
+
+static inline void nb8800_maskb(struct nb8800_priv *priv, int reg,
+				u32 mask, u32 val)
+{
+	u32 old = nb8800_readb(priv, reg);
+	u32 new = (old & ~mask) | (val & mask);
+
+	if (new != old)
+		nb8800_writeb(priv, reg, new);
+}
+
+static inline void nb8800_maskl(struct nb8800_priv *priv, int reg,
+				u32 mask, u32 val)
+{
+	u32 old = nb8800_readl(priv, reg);
+	u32 new = (old & ~mask) | (val & mask);
+
+	if (new != old)
+		nb8800_writel(priv, reg, new);
+}
+
+static inline void nb8800_modb(struct nb8800_priv *priv, int reg, u8 bits,
+			       bool set)
+{
+	nb8800_maskb(priv, reg, bits, set ? bits : 0);
+}
+
+static inline void nb8800_setb(struct nb8800_priv *priv, int reg, u8 bits)
+{
+	nb8800_maskb(priv, reg, bits, bits);
+}
+
+static inline void nb8800_clearb(struct nb8800_priv *priv, int reg, u8 bits)
+{
+	nb8800_maskb(priv, reg, bits, 0);
+}
+
+static inline void nb8800_modl(struct nb8800_priv *priv, int reg, u32 bits,
+			       bool set)
+{
+	nb8800_maskl(priv, reg, bits, set ? bits : 0);
+}
+
+static inline void nb8800_setl(struct nb8800_priv *priv, int reg, u32 bits)
+{
+	nb8800_maskl(priv, reg, bits, bits);
+}
+
+static inline void nb8800_clearl(struct nb8800_priv *priv, int reg, u32 bits)
+{
+	nb8800_maskl(priv, reg, bits, 0);
+}
+
+static int nb8800_mdio_wait(struct mii_bus *bus)
+{
+	struct nb8800_priv *priv = bus->priv;
+	u32 val;
+
+	return readl_poll_timeout_atomic(priv->base + NB8800_MDIO_CMD,
+					 val, !(val & MDIO_CMD_GO), 1, 1000);
+}
+
+static int nb8800_mdio_cmd(struct mii_bus *bus, u32 cmd)
+{
+	struct nb8800_priv *priv = bus->priv;
+	int err;
+
+	err = nb8800_mdio_wait(bus);
+	if (err)
+		return err;
+
+	nb8800_writel(priv, NB8800_MDIO_CMD, cmd);
+	udelay(10);
+	nb8800_writel(priv, NB8800_MDIO_CMD, cmd | MDIO_CMD_GO);
+
+	return nb8800_mdio_wait(bus);
+}
+
+static int nb8800_mdio_read(struct mii_bus *bus, int phy_id, int reg)
+{
+	struct nb8800_priv *priv = bus->priv;
+	u32 val;
+	int err;
+
+	err = nb8800_mdio_cmd(bus, MDIO_CMD_ADDR(phy_id) | MDIO_CMD_REG(reg));
+	if (err)
+		return err;
+
+	val = nb8800_readl(priv, NB8800_MDIO_STS);
+	if (val & MDIO_STS_ERR)
+		return 0xffff;
+
+	return val & 0xffff;
+}
+
+static int nb8800_mdio_write(struct mii_bus *bus, int phy_id, int reg, u16 val)
+{
+	u32 cmd = MDIO_CMD_ADDR(phy_id) | MDIO_CMD_REG(reg) |
+		MDIO_CMD_DATA(val) | MDIO_CMD_WR;
+
+	return nb8800_mdio_cmd(bus, cmd);
+}
+
+static void nb8800_mac_tx(struct net_device *dev, bool enable)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+
+	while (nb8800_readl(priv, NB8800_TXC_CR) & TCR_EN)
+		cpu_relax();
+
+	nb8800_modb(priv, NB8800_TX_CTL1, TX_EN, enable);
+}
+
+static void nb8800_mac_rx(struct net_device *dev, bool enable)
+{
+	nb8800_modb(netdev_priv(dev), NB8800_RX_CTL, RX_EN, enable);
+}
+
+static void nb8800_mac_af(struct net_device *dev, bool enable)
+{
+	nb8800_modb(netdev_priv(dev), NB8800_RX_CTL, RX_AF_EN, enable);
+}
+
+static void nb8800_start_rx(struct net_device *dev)
+{
+	nb8800_setl(netdev_priv(dev), NB8800_RXC_CR, RCR_EN);
+}
+
+static int nb8800_alloc_rx(struct net_device *dev, unsigned int i, bool napi)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	struct nb8800_rx_desc *rxd = &priv->rx_descs[i];
+	struct nb8800_rx_buf *rxb = &priv->rx_bufs[i];
+	int size = L1_CACHE_ALIGN(RX_BUF_SIZE);
+	dma_addr_t dma_addr;
+	struct page *page;
+	unsigned long offset;
+	void *data;
+
+	data = napi ? napi_alloc_frag(size) : netdev_alloc_frag(size);
+	if (!data)
+		return -ENOMEM;
+
+	page = virt_to_head_page(data);
+	offset = data - page_address(page);
+
+	dma_addr = dma_map_page(&dev->dev, page, offset, RX_BUF_SIZE,
+				DMA_FROM_DEVICE);
+
+	if (dma_mapping_error(&dev->dev, dma_addr)) {
+		skb_free_frag(data);
+		return -ENOMEM;
+	}
+
+	rxb->page = page;
+	rxb->offset = offset;
+	rxd->desc.s_addr = dma_addr;
+
+	return 0;
+}
+
+static void nb8800_receive(struct net_device *dev, unsigned int i,
+			   unsigned int len)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	struct nb8800_rx_desc *rxd = &priv->rx_descs[i];
+	struct page *page = priv->rx_bufs[i].page;
+	int offset = priv->rx_bufs[i].offset;
+	void *data = page_address(page) + offset;
+	dma_addr_t dma = rxd->desc.s_addr;
+	struct sk_buff *skb;
+	unsigned int size;
+	int err;
+
+	size = len <= RX_COPYBREAK ? len : RX_COPYHDR;
+
+	skb = napi_alloc_skb(&priv->napi, size);
+	if (!skb) {
+		netdev_err(dev, "rx skb allocation failed\n");
+		dev->stats.rx_dropped++;
+		return;
+	}
+
+	if (len <= RX_COPYBREAK) {
+		dma_sync_single_for_cpu(&dev->dev, dma, len, DMA_FROM_DEVICE);
+		memcpy(skb_put(skb, len), data, len);
+		dma_sync_single_for_device(&dev->dev, dma, len,
+					   DMA_FROM_DEVICE);
+	} else {
+		err = nb8800_alloc_rx(dev, i, true);
+		if (err) {
+			netdev_err(dev, "rx buffer allocation failed\n");
+			dev->stats.rx_dropped++;
+			return;
+		}
+
+		dma_unmap_page(&dev->dev, dma, RX_BUF_SIZE, DMA_FROM_DEVICE);
+		memcpy(skb_put(skb, RX_COPYHDR), data, RX_COPYHDR);
+		skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page,
+				offset + RX_COPYHDR, len - RX_COPYHDR,
+				RX_BUF_SIZE);
+	}
+
+	skb->protocol = eth_type_trans(skb, dev);
+	napi_gro_receive(&priv->napi, skb);
+}
+
+static void nb8800_rx_error(struct net_device *dev, u32 report)
+{
+	if (report & RX_LENGTH_ERR)
+		dev->stats.rx_length_errors++;
+
+	if (report & RX_FCS_ERR)
+		dev->stats.rx_crc_errors++;
+
+	if (report & RX_FIFO_OVERRUN)
+		dev->stats.rx_fifo_errors++;
+
+	if (report & RX_ALIGNMENT_ERROR)
+		dev->stats.rx_frame_errors++;
+
+	dev->stats.rx_errors++;
+}
+
+static int nb8800_poll(struct napi_struct *napi, int budget)
+{
+	struct net_device *dev = napi->dev;
+	struct nb8800_priv *priv = netdev_priv(dev);
+	struct nb8800_rx_desc *rxd;
+	unsigned int last = priv->rx_eoc;
+	unsigned int next;
+	int work = 0;
+
+	nb8800_tx_done(dev);
+
+again:
+	while (work < budget) {
+		struct nb8800_rx_buf *rxb;
+		unsigned int len;
+
+		next = (last + 1) % RX_DESC_COUNT;
+
+		rxb = &priv->rx_bufs[next];
+		rxd = &priv->rx_descs[next];
+
+		if (!rxd->report)
+			break;
+
+		len = RX_BYTES_TRANSFERRED(rxd->report);
+
+		if (IS_RX_ERROR(rxd->report))
+			nb8800_rx_error(dev, rxd->report);
+		else
+			nb8800_receive(dev, next, len);
+
+		dev->stats.rx_packets++;
+		dev->stats.rx_bytes += len;
+
+		if (rxd->report & RX_MULTICAST_PKT)
+			dev->stats.multicast++;
+
+		rxd->report = 0;
+		last = next;
+		work++;
+	}
+
+	if (work) {
+		priv->rx_descs[last].desc.config |= DESC_EOC;
+		wmb();	/* ensure new EOC is written before clearing old */
+		priv->rx_descs[priv->rx_eoc].desc.config &= ~DESC_EOC;
+		priv->rx_eoc = last;
+		nb8800_start_rx(dev);
+	}
+
+	if (work < budget) {
+		nb8800_writel(priv, NB8800_RX_ITR, priv->rx_itr_irq);
+
+		/* If a packet arrived after we last checked but
+		 * before writing RX_ITR, the interrupt will be
+		 * delayed, so we retrieve it now.
+		 */
+		if (priv->rx_descs[next].report)
+			goto again;
+
+		napi_complete_done(napi, work);
+	}
+
+	return work;
+}
+
+static void __nb8800_tx_dma_start(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	struct nb8800_tx_buf *txb;
+	u32 txc_cr;
+
+	txb = &priv->tx_bufs[priv->tx_queue];
+	if (!txb->ready)
+		return;
+
+	txc_cr = nb8800_readl(priv, NB8800_TXC_CR);
+	if (txc_cr & TCR_EN)
+		return;
+
+	nb8800_writel(priv, NB8800_TX_DESC_ADDR, txb->dma_desc);
+	wmb();		/* ensure desc addr is written before starting DMA */
+	nb8800_writel(priv, NB8800_TXC_CR, txc_cr | TCR_EN);
+
+	priv->tx_queue = (priv->tx_queue + txb->chain_len) % TX_DESC_COUNT;
+}
+
+static void nb8800_tx_dma_start(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+
+	spin_lock_irq(&priv->tx_lock);
+	__nb8800_tx_dma_start(dev);
+	spin_unlock_irq(&priv->tx_lock);
+}
+
+static void nb8800_tx_dma_start_irq(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+
+	spin_lock(&priv->tx_lock);
+	__nb8800_tx_dma_start(dev);
+	spin_unlock(&priv->tx_lock);
+}
+
+static int nb8800_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	struct nb8800_tx_desc *txd;
+	struct nb8800_tx_buf *txb;
+	struct nb8800_dma_desc *desc;
+	dma_addr_t dma_addr;
+	unsigned int dma_len;
+	unsigned int align;
+	unsigned int next;
+
+	if (atomic_read(&priv->tx_free) <= NB8800_DESC_LOW) {
+		netif_stop_queue(dev);
+		return NETDEV_TX_BUSY;
+	}
+
+	align = (8 - (uintptr_t)skb->data) & 7;
+
+	dma_len = skb->len - align;
+	dma_addr = dma_map_single(&dev->dev, skb->data + align,
+				  dma_len, DMA_TO_DEVICE);
+
+	if (dma_mapping_error(&dev->dev, dma_addr)) {
+		netdev_err(dev, "tx dma mapping error\n");
+		kfree_skb(skb);
+		dev->stats.tx_dropped++;
+		return NETDEV_TX_OK;
+	}
+
+	if (atomic_dec_return(&priv->tx_free) <= NB8800_DESC_LOW) {
+		netif_stop_queue(dev);
+		skb->xmit_more = 0;
+	}
+
+	next = priv->tx_next;
+	txb = &priv->tx_bufs[next];
+	txd = &priv->tx_descs[next];
+	desc = &txd->desc[0];
+
+	next = (next + 1) % TX_DESC_COUNT;
+
+	if (align) {
+		memcpy(txd->buf, skb->data, align);
+
+		desc->s_addr =
+			txb->dma_desc + offsetof(struct nb8800_tx_desc, buf);
+		desc->n_addr = txb->dma_desc + sizeof(txd->desc[0]);
+		desc->config = DESC_BTS(2) | DESC_DS | align;
+
+		desc++;
+	}
+
+	desc->s_addr = dma_addr;
+	desc->n_addr = priv->tx_bufs[next].dma_desc;
+	desc->config = DESC_BTS(2) | DESC_DS | DESC_EOF | dma_len;
+
+	if (!skb->xmit_more)
+		desc->config |= DESC_EOC;
+
+	txb->skb = skb;
+	txb->dma_addr = dma_addr;
+	txb->dma_len = dma_len;
+
+	if (!priv->tx_chain) {
+		txb->chain_len = 1;
+		priv->tx_chain = txb;
+	} else {
+		priv->tx_chain->chain_len++;
+	}
+
+	netdev_sent_queue(dev, skb->len);
+
+	priv->tx_next = next;
+
+	if (!skb->xmit_more) {
+		smp_wmb();
+		priv->tx_chain->ready = true;
+		priv->tx_chain = NULL;
+		nb8800_tx_dma_start(dev);
+	}
+
+	return NETDEV_TX_OK;
+}
+
+static void nb8800_tx_error(struct net_device *dev, u32 report)
+{
+	if (report & TX_LATE_COLLISION)
+		dev->stats.collisions++;
+
+	if (report & TX_PACKET_DROPPED)
+		dev->stats.tx_dropped++;
+
+	if (report & TX_FIFO_UNDERRUN)
+		dev->stats.tx_fifo_errors++;
+
+	dev->stats.tx_errors++;
+}
+
+static void nb8800_tx_done(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	unsigned int limit = priv->tx_next;
+	unsigned int done = priv->tx_done;
+	unsigned int packets = 0;
+	unsigned int len = 0;
+
+	while (done != limit) {
+		struct nb8800_tx_desc *txd = &priv->tx_descs[done];
+		struct nb8800_tx_buf *txb = &priv->tx_bufs[done];
+		struct sk_buff *skb;
+
+		if (!txd->report)
+			break;
+
+		skb = txb->skb;
+		len += skb->len;
+
+		dma_unmap_single(&dev->dev, txb->dma_addr, txb->dma_len,
+				 DMA_TO_DEVICE);
+
+		if (IS_TX_ERROR(txd->report)) {
+			nb8800_tx_error(dev, txd->report);
+			kfree_skb(skb);
+		} else {
+			consume_skb(skb);
+		}
+
+		dev->stats.tx_packets++;
+		dev->stats.tx_bytes += TX_BYTES_TRANSFERRED(txd->report);
+		dev->stats.collisions += TX_EARLY_COLLISIONS(txd->report);
+
+		txb->skb = NULL;
+		txb->ready = false;
+		txd->report = 0;
+
+		done = (done + 1) % TX_DESC_COUNT;
+		packets++;
+	}
+
+	if (packets) {
+		smp_mb__before_atomic();
+		atomic_add(packets, &priv->tx_free);
+		netdev_completed_queue(dev, packets, len);
+		netif_wake_queue(dev);
+		priv->tx_done = done;
+	}
+}
+
+static irqreturn_t nb8800_irq(int irq, void *dev_id)
+{
+	struct net_device *dev = dev_id;
+	struct nb8800_priv *priv = netdev_priv(dev);
+	irqreturn_t ret = IRQ_NONE;
+	u32 val;
+
+	/* tx interrupt */
+	val = nb8800_readl(priv, NB8800_TXC_SR);
+	if (val) {
+		nb8800_writel(priv, NB8800_TXC_SR, val);
+
+		if (val & TSR_DI)
+			nb8800_tx_dma_start_irq(dev);
+
+		if (val & TSR_TI)
+			napi_schedule_irqoff(&priv->napi);
+
+		if (unlikely(val & TSR_DE))
+			netdev_err(dev, "TX DMA error\n");
+
+		/* should never happen with automatic status retrieval */
+		if (unlikely(val & TSR_TO))
+			netdev_err(dev, "TX Status FIFO overflow\n");
+
+		ret = IRQ_HANDLED;
+	}
+
+	/* rx interrupt */
+	val = nb8800_readl(priv, NB8800_RXC_SR);
+	if (val) {
+		nb8800_writel(priv, NB8800_RXC_SR, val);
+
+		if (likely(val & (RSR_RI | RSR_DI))) {
+			nb8800_writel(priv, NB8800_RX_ITR, priv->rx_itr_poll);
+			napi_schedule_irqoff(&priv->napi);
+		}
+
+		if (unlikely(val & RSR_DE))
+			netdev_err(dev, "RX DMA error\n");
+
+		/* should never happen with automatic status retrieval */
+		if (unlikely(val & RSR_RO))
+			netdev_err(dev, "RX Status FIFO overflow\n");
+
+		ret = IRQ_HANDLED;
+	}
+
+	return ret;
+}
+
+static void nb8800_mac_config(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	bool gigabit = priv->speed == SPEED_1000;
+	u32 mac_mode_mask = RGMII_MODE | HALF_DUPLEX | GMAC_MODE;
+	u32 mac_mode = 0;
+	u32 slot_time;
+	u32 phy_clk;
+	u32 ict;
+
+	if (!priv->duplex)
+		mac_mode |= HALF_DUPLEX;
+
+	if (gigabit) {
+		if (priv->phy_mode == PHY_INTERFACE_MODE_RGMII)
+			mac_mode |= RGMII_MODE;
+
+		mac_mode |= GMAC_MODE;
+		phy_clk = 125000000;
+
+		/* Should be 512 but register is only 8 bits */
+		slot_time = 255;
+	} else {
+		phy_clk = 25000000;
+		slot_time = 128;
+	}
+
+	ict = DIV_ROUND_UP(phy_clk, clk_get_rate(priv->clk));
+
+	nb8800_writeb(priv, NB8800_IC_THRESHOLD, ict);
+	nb8800_writeb(priv, NB8800_SLOT_TIME, slot_time);
+	nb8800_maskb(priv, NB8800_MAC_MODE, mac_mode_mask, mac_mode);
+}
+
+static void nb8800_pause_config(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	struct phy_device *phydev = priv->phydev;
+	u32 rxcr;
+
+	if (priv->pause_aneg) {
+		if (!phydev || !phydev->link)
+			return;
+
+		priv->pause_rx = phydev->pause;
+		priv->pause_tx = phydev->pause ^ phydev->asym_pause;
+	}
+
+	nb8800_modb(priv, NB8800_RX_CTL, RX_PAUSE_EN, priv->pause_rx);
+
+	rxcr = nb8800_readl(priv, NB8800_RXC_CR);
+	if (!!(rxcr & RCR_FL) == priv->pause_tx)
+		return;
+
+	if (netif_running(dev)) {
+		napi_disable(&priv->napi);
+		netif_tx_lock_bh(dev);
+		nb8800_dma_stop(dev);
+		nb8800_modl(priv, NB8800_RXC_CR, RCR_FL, priv->pause_tx);
+		nb8800_start_rx(dev);
+		netif_tx_unlock_bh(dev);
+		napi_enable(&priv->napi);
+	} else {
+		nb8800_modl(priv, NB8800_RXC_CR, RCR_FL, priv->pause_tx);
+	}
+}
+
+static void nb8800_link_reconfigure(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	struct phy_device *phydev = priv->phydev;
+	int change = 0;
+
+	if (phydev->link) {
+		if (phydev->speed != priv->speed) {
+			priv->speed = phydev->speed;
+			change = 1;
+		}
+
+		if (phydev->duplex != priv->duplex) {
+			priv->duplex = phydev->duplex;
+			change = 1;
+		}
+
+		if (change)
+			nb8800_mac_config(dev);
+
+		nb8800_pause_config(dev);
+	}
+
+	if (phydev->link != priv->link) {
+		priv->link = phydev->link;
+		change = 1;
+	}
+
+	if (change)
+		phy_print_status(priv->phydev);
+}
+
+static void nb8800_update_mac_addr(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	int i;
+
+	for (i = 0; i < ETH_ALEN; i++)
+		nb8800_writeb(priv, NB8800_SRC_ADDR(i), dev->dev_addr[i]);
+
+	for (i = 0; i < ETH_ALEN; i++)
+		nb8800_writeb(priv, NB8800_UC_ADDR(i), dev->dev_addr[i]);
+}
+
+static int nb8800_set_mac_address(struct net_device *dev, void *addr)
+{
+	struct sockaddr *sock = addr;
+
+	if (netif_running(dev))
+		return -EBUSY;
+
+	ether_addr_copy(dev->dev_addr, sock->sa_data);
+	nb8800_update_mac_addr(dev);
+
+	return 0;
+}
+
+static void nb8800_mc_init(struct net_device *dev, int val)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+
+	nb8800_writeb(priv, NB8800_MC_INIT, val);
+	readb_poll_timeout_atomic(priv->base + NB8800_MC_INIT, val, !val,
+				  1, 1000);
+}
+
+static void nb8800_set_rx_mode(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	struct netdev_hw_addr *ha;
+	int i;
+
+	if (dev->flags & (IFF_PROMISC | IFF_ALLMULTI)) {
+		nb8800_mac_af(dev, false);
+		return;
+	}
+
+	nb8800_mac_af(dev, true);
+	nb8800_mc_init(dev, 0);
+
+	netdev_for_each_mc_addr(ha, dev) {
+		for (i = 0; i < ETH_ALEN; i++)
+			nb8800_writeb(priv, NB8800_MC_ADDR(i), ha->addr[i]);
+
+		nb8800_mc_init(dev, 0xff);
+	}
+}
+
+#define RX_DESC_SIZE (RX_DESC_COUNT * sizeof(struct nb8800_rx_desc))
+#define TX_DESC_SIZE (TX_DESC_COUNT * sizeof(struct nb8800_tx_desc))
+
+static void nb8800_dma_free(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	unsigned int i;
+
+	if (priv->rx_bufs) {
+		for (i = 0; i < RX_DESC_COUNT; i++)
+			if (priv->rx_bufs[i].page)
+				put_page(priv->rx_bufs[i].page);
+
+		kfree(priv->rx_bufs);
+		priv->rx_bufs = NULL;
+	}
+
+	if (priv->tx_bufs) {
+		for (i = 0; i < TX_DESC_COUNT; i++)
+			kfree_skb(priv->tx_bufs[i].skb);
+
+		kfree(priv->tx_bufs);
+		priv->tx_bufs = NULL;
+	}
+
+	if (priv->rx_descs) {
+		dma_free_coherent(dev->dev.parent, RX_DESC_SIZE, priv->rx_descs,
+				  priv->rx_desc_dma);
+		priv->rx_descs = NULL;
+	}
+
+	if (priv->tx_descs) {
+		dma_free_coherent(dev->dev.parent, TX_DESC_SIZE, priv->tx_descs,
+				  priv->tx_desc_dma);
+		priv->tx_descs = NULL;
+	}
+}
+
+static void nb8800_dma_reset(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	struct nb8800_rx_desc *rxd;
+	struct nb8800_tx_desc *txd;
+	unsigned int i;
+
+	for (i = 0; i < RX_DESC_COUNT; i++) {
+		dma_addr_t rx_dma = priv->rx_desc_dma + i * sizeof(*rxd);
+
+		rxd = &priv->rx_descs[i];
+		rxd->desc.n_addr = rx_dma + sizeof(*rxd);
+		rxd->desc.r_addr =
+			rx_dma + offsetof(struct nb8800_rx_desc, report);
+		rxd->desc.config = priv->rx_dma_config;
+		rxd->report = 0;
+	}
+
+	rxd->desc.n_addr = priv->rx_desc_dma;
+	rxd->desc.config |= DESC_EOC;
+
+	priv->rx_eoc = RX_DESC_COUNT - 1;
+
+	for (i = 0; i < TX_DESC_COUNT; i++) {
+		struct nb8800_tx_buf *txb = &priv->tx_bufs[i];
+		dma_addr_t r_dma = txb->dma_desc +
+			offsetof(struct nb8800_tx_desc, report);
+
+		txd = &priv->tx_descs[i];
+		txd->desc[0].r_addr = r_dma;
+		txd->desc[1].r_addr = r_dma;
+		txd->report = 0;
+	}
+
+	priv->tx_next = 0;
+	priv->tx_queue = 0;
+	priv->tx_done = 0;
+	atomic_set(&priv->tx_free, TX_DESC_COUNT);
+
+	nb8800_writel(priv, NB8800_RX_DESC_ADDR, priv->rx_desc_dma);
+
+	wmb();		/* ensure all setup is written before starting */
+}
+
+static int nb8800_dma_init(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	unsigned int n_rx = RX_DESC_COUNT;
+	unsigned int n_tx = TX_DESC_COUNT;
+	unsigned int i;
+	int err;
+
+	priv->rx_descs = dma_alloc_coherent(dev->dev.parent, RX_DESC_SIZE,
+					    &priv->rx_desc_dma, GFP_KERNEL);
+	if (!priv->rx_descs)
+		goto err_out;
+
+	priv->rx_bufs = kcalloc(n_rx, sizeof(*priv->rx_bufs), GFP_KERNEL);
+	if (!priv->rx_bufs)
+		goto err_out;
+
+	for (i = 0; i < n_rx; i++) {
+		err = nb8800_alloc_rx(dev, i, false);
+		if (err)
+			goto err_out;
+	}
+
+	priv->tx_descs = dma_alloc_coherent(dev->dev.parent, TX_DESC_SIZE,
+					    &priv->tx_desc_dma, GFP_KERNEL);
+	if (!priv->tx_descs)
+		goto err_out;
+
+	priv->tx_bufs = kcalloc(n_tx, sizeof(*priv->tx_bufs), GFP_KERNEL);
+	if (!priv->tx_bufs)
+		goto err_out;
+
+	for (i = 0; i < n_tx; i++)
+		priv->tx_bufs[i].dma_desc =
+			priv->tx_desc_dma + i * sizeof(struct nb8800_tx_desc);
+
+	nb8800_dma_reset(dev);
+
+	return 0;
+
+err_out:
+	nb8800_dma_free(dev);
+
+	return -ENOMEM;
+}
+
+static int nb8800_dma_stop(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	struct nb8800_tx_buf *txb = &priv->tx_bufs[0];
+	struct nb8800_tx_desc *txd = &priv->tx_descs[0];
+	int retry = 5;
+	u32 txcr;
+	u32 rxcr;
+	int err;
+	unsigned int i;
+
+	/* wait for tx to finish */
+	err = readl_poll_timeout_atomic(priv->base + NB8800_TXC_CR, txcr,
+					!(txcr & TCR_EN) &&
+					priv->tx_done == priv->tx_next,
+					1000, 1000000);
+	if (err)
+		return err;
+
+	/* The rx DMA only stops if it reaches the end of chain.
+	 * To make this happen, we set the EOC flag on all rx
+	 * descriptors, put the device in loopback mode, and send
+	 * a few dummy frames.  The interrupt handler will ignore
+	 * these since NAPI is disabled and no real frames are in
+	 * the tx queue.
+	 */
+
+	for (i = 0; i < RX_DESC_COUNT; i++)
+		priv->rx_descs[i].desc.config |= DESC_EOC;
+
+	txd->desc[0].s_addr =
+		txb->dma_desc + offsetof(struct nb8800_tx_desc, buf);
+	txd->desc[0].config = DESC_BTS(2) | DESC_DS | DESC_EOF | DESC_EOC | 8;
+	memset(txd->buf, 0, sizeof(txd->buf));
+
+	nb8800_mac_af(dev, false);
+	nb8800_setb(priv, NB8800_MAC_MODE, LOOPBACK_EN);
+
+	do {
+		nb8800_writel(priv, NB8800_TX_DESC_ADDR, txb->dma_desc);
+		wmb();
+		nb8800_writel(priv, NB8800_TXC_CR, txcr | TCR_EN);
+
+		err = readl_poll_timeout_atomic(priv->base + NB8800_RXC_CR,
+						rxcr, !(rxcr & RCR_EN),
+						1000, 100000);
+	} while (err && --retry);
+
+	nb8800_mac_af(dev, true);
+	nb8800_clearb(priv, NB8800_MAC_MODE, LOOPBACK_EN);
+	nb8800_dma_reset(dev);
+
+	return retry ? 0 : -ETIMEDOUT;
+}
+
+static void nb8800_pause_adv(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	u32 adv = 0;
+
+	if (!priv->phydev)
+		return;
+
+	if (priv->pause_rx)
+		adv |= ADVERTISED_Pause | ADVERTISED_Asym_Pause;
+	if (priv->pause_tx)
+		adv ^= ADVERTISED_Asym_Pause;
+
+	priv->phydev->supported |= adv;
+	priv->phydev->advertising |= adv;
+}
+
+static int nb8800_open(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	int err;
+
+	/* clear any pending interrupts */
+	nb8800_writel(priv, NB8800_RXC_SR, 0xf);
+	nb8800_writel(priv, NB8800_TXC_SR, 0xf);
+
+	err = nb8800_dma_init(dev);
+	if (err)
+		return err;
+
+	err = request_irq(dev->irq, nb8800_irq, 0, dev_name(&dev->dev), dev);
+	if (err)
+		goto err_free_dma;
+
+	nb8800_mac_rx(dev, true);
+	nb8800_mac_tx(dev, true);
+
+	priv->phydev = of_phy_connect(dev, priv->phy_node,
+				      nb8800_link_reconfigure, 0,
+				      priv->phy_mode);
+	if (!priv->phydev)
+		goto err_free_irq;
+
+	nb8800_pause_adv(dev);
+
+	netdev_reset_queue(dev);
+	napi_enable(&priv->napi);
+	netif_start_queue(dev);
+
+	nb8800_start_rx(dev);
+	phy_start(priv->phydev);
+
+	return 0;
+
+err_free_irq:
+	free_irq(dev->irq, dev);
+err_free_dma:
+	nb8800_dma_free(dev);
+
+	return err;
+}
+
+static int nb8800_stop(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+
+	phy_stop(priv->phydev);
+
+	netif_stop_queue(dev);
+	napi_disable(&priv->napi);
+
+	nb8800_dma_stop(dev);
+	nb8800_mac_rx(dev, false);
+	nb8800_mac_tx(dev, false);
+
+	phy_disconnect(priv->phydev);
+	priv->phydev = NULL;
+
+	free_irq(dev->irq, dev);
+
+	nb8800_dma_free(dev);
+
+	return 0;
+}
+
+static int nb8800_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+
+	return phy_mii_ioctl(priv->phydev, rq, cmd);
+}
+
+static const struct net_device_ops nb8800_netdev_ops = {
+	.ndo_open		= nb8800_open,
+	.ndo_stop		= nb8800_stop,
+	.ndo_start_xmit		= nb8800_xmit,
+	.ndo_set_mac_address	= nb8800_set_mac_address,
+	.ndo_set_rx_mode	= nb8800_set_rx_mode,
+	.ndo_do_ioctl		= nb8800_ioctl,
+	.ndo_change_mtu		= eth_change_mtu,
+	.ndo_validate_addr	= eth_validate_addr,
+};
+
+static int nb8800_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+
+	if (!priv->phydev)
+		return -ENODEV;
+
+	return phy_ethtool_gset(priv->phydev, cmd);
+}
+
+static int nb8800_set_settings(struct net_device *dev, struct ethtool_cmd *cmd)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+
+	if (!priv->phydev)
+		return -ENODEV;
+
+	return phy_ethtool_sset(priv->phydev, cmd);
+}
+
+static int nb8800_nway_reset(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+
+	if (!priv->phydev)
+		return -ENODEV;
+
+	return genphy_restart_aneg(priv->phydev);
+}
+
+static void nb8800_get_pauseparam(struct net_device *dev,
+				  struct ethtool_pauseparam *pp)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+
+	pp->autoneg = priv->pause_aneg;
+	pp->rx_pause = priv->pause_rx;
+	pp->tx_pause = priv->pause_tx;
+}
+
+static int nb8800_set_pauseparam(struct net_device *dev,
+				 struct ethtool_pauseparam *pp)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+
+	priv->pause_aneg = pp->autoneg;
+	priv->pause_rx = pp->rx_pause;
+	priv->pause_tx = pp->tx_pause;
+
+	nb8800_pause_adv(dev);
+
+	if (!priv->pause_aneg)
+		nb8800_pause_config(dev);
+	else if (priv->phydev)
+		phy_start_aneg(priv->phydev);
+
+	return 0;
+}
+
+static const char nb8800_stats_names[][ETH_GSTRING_LEN] = {
+	"rx_bytes_ok",
+	"rx_frames_ok",
+	"rx_undersize_frames",
+	"rx_fragment_frames",
+	"rx_64_byte_frames",
+	"rx_127_byte_frames",
+	"rx_255_byte_frames",
+	"rx_511_byte_frames",
+	"rx_1023_byte_frames",
+	"rx_max_size_frames",
+	"rx_oversize_frames",
+	"rx_bad_fcs_frames",
+	"rx_broadcast_frames",
+	"rx_multicast_frames",
+	"rx_control_frames",
+	"rx_pause_frames",
+	"rx_unsup_control_frames",
+	"rx_align_error_frames",
+	"rx_overrun_frames",
+	"rx_jabber_frames",
+	"rx_bytes",
+	"rx_frames",
+
+	"tx_bytes_ok",
+	"tx_frames_ok",
+	"tx_64_byte_frames",
+	"tx_127_byte_frames",
+	"tx_255_byte_frames",
+	"tx_511_byte_frames",
+	"tx_1023_byte_frames",
+	"tx_max_size_frames",
+	"tx_oversize_frames",
+	"tx_broadcast_frames",
+	"tx_multicast_frames",
+	"tx_control_frames",
+	"tx_pause_frames",
+	"tx_underrun_frames",
+	"tx_single_collision_frames",
+	"tx_multi_collision_frames",
+	"tx_deferred_collision_frames",
+	"tx_late_collision_frames",
+	"tx_excessive_collision_frames",
+	"tx_bytes",
+	"tx_frames",
+	"tx_collisions",
+};
+
+#define NB8800_NUM_STATS ARRAY_SIZE(nb8800_stats_names)
+
+static int nb8800_get_sset_count(struct net_device *dev, int sset)
+{
+	if (sset == ETH_SS_STATS)
+		return NB8800_NUM_STATS;
+
+	return -EOPNOTSUPP;
+}
+
+static void nb8800_get_strings(struct net_device *dev, u32 sset, u8 *buf)
+{
+	if (sset == ETH_SS_STATS)
+		memcpy(buf, &nb8800_stats_names, sizeof(nb8800_stats_names));
+}
+
+static u32 nb8800_read_stat(struct net_device *dev, int index)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+
+	nb8800_writeb(priv, NB8800_STAT_INDEX, index);
+
+	return nb8800_readl(priv, NB8800_STAT_DATA);
+}
+
+static void nb8800_get_ethtool_stats(struct net_device *dev,
+				     struct ethtool_stats *estats, u64 *st)
+{
+	unsigned int i;
+	u32 rx, tx;
+
+	for (i = 0; i < NB8800_NUM_STATS / 2; i++) {
+		rx = nb8800_read_stat(dev, i);
+		tx = nb8800_read_stat(dev, i | 0x80);
+		st[i] = rx;
+		st[i + NB8800_NUM_STATS / 2] = tx;
+	}
+}
+
+static const struct ethtool_ops nb8800_ethtool_ops = {
+	.get_settings		= nb8800_get_settings,
+	.set_settings		= nb8800_set_settings,
+	.nway_reset		= nb8800_nway_reset,
+	.get_link		= ethtool_op_get_link,
+	.get_pauseparam		= nb8800_get_pauseparam,
+	.set_pauseparam		= nb8800_set_pauseparam,
+	.get_sset_count		= nb8800_get_sset_count,
+	.get_strings		= nb8800_get_strings,
+	.get_ethtool_stats	= nb8800_get_ethtool_stats,
+};
+
+static int nb8800_hw_init(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	u32 val;
+
+	val = TX_RETRY_EN | TX_PAD_EN | TX_APPEND_FCS;
+	nb8800_writeb(priv, NB8800_TX_CTL1, val);
+
+	/* Collision retry count */
+	nb8800_writeb(priv, NB8800_TX_CTL2, 5);
+
+	val = RX_PAD_STRIP | RX_AF_EN;
+	nb8800_writeb(priv, NB8800_RX_CTL, val);
+
+	/* Chosen by fair dice roll */
+	nb8800_writeb(priv, NB8800_RANDOM_SEED, 4);
+
+	/* TX cycles per deferral period */
+	nb8800_writeb(priv, NB8800_TX_SDP, 12);
+
+	/* The following three threshold values have been
+	 * experimentally determined for good results.
+	 */
+
+	/* RX/TX FIFO threshold for partial empty (64-bit entries) */
+	nb8800_writeb(priv, NB8800_PE_THRESHOLD, 0);
+
+	/* RX/TX FIFO threshold for partial full (64-bit entries) */
+	nb8800_writeb(priv, NB8800_PF_THRESHOLD, 255);
+
+	/* Buffer size for transmit (64-bit entries) */
+	nb8800_writeb(priv, NB8800_TX_BUFSIZE, 64);
+
+	/* Configure tx DMA */
+
+	val = nb8800_readl(priv, NB8800_TXC_CR);
+	val &= TCR_LE;		/* keep endian setting */
+	val |= TCR_DM;		/* DMA descriptor mode */
+	val |= TCR_RS;		/* automatically store tx status  */
+	val |= TCR_DIE;		/* interrupt on DMA chain completion */
+	val |= TCR_TFI(7);	/* interrupt after 7 frames transmitted */
+	val |= TCR_BTS(2);	/* 32-byte bus transaction size */
+	nb8800_writel(priv, NB8800_TXC_CR, val);
+
+	/* TX complete interrupt after 10 ms or 7 frames (see above) */
+	val = clk_get_rate(priv->clk) / 100;
+	nb8800_writel(priv, NB8800_TX_ITR, val);
+
+	/* Configure rx DMA */
+
+	val = nb8800_readl(priv, NB8800_RXC_CR);
+	val &= RCR_LE;		/* keep endian setting */
+	val |= RCR_DM;		/* DMA descriptor mode */
+	val |= RCR_RS;		/* automatically store rx status */
+	val |= RCR_DIE;		/* interrupt at end of DMA chain */
+	val |= RCR_RFI(7);	/* interrupt after 7 frames received */
+	val |= RCR_BTS(2);	/* 32-byte bus transaction size */
+	nb8800_writel(priv, NB8800_RXC_CR, val);
+
+	/* The rx interrupt can fire before the DMA has completed
+	 * unless a small delay is added.  50 us is hopefully enough.
+	 */
+	priv->rx_itr_irq = clk_get_rate(priv->clk) / 20000;
+
+	/* In NAPI poll mode we want to disable interrupts, but the
+	 * hardware does not permit this.  Delay 10 ms instead.
+	 */
+	priv->rx_itr_poll = clk_get_rate(priv->clk) / 100;
+
+	nb8800_writel(priv, NB8800_RX_ITR, priv->rx_itr_irq);
+
+	priv->rx_dma_config = RX_BUF_SIZE | DESC_BTS(2) | DESC_DS | DESC_EOF;
+
+	/* Flow control settings */
+
+	/* Pause time of 0.1 ms */
+	val = 100000 / 512;
+	nb8800_writeb(priv, NB8800_PQ1, val >> 8);
+	nb8800_writeb(priv, NB8800_PQ2, val & 0xff);
+
+	/* Auto-negotiate by default */
+	priv->pause_aneg = true;
+	priv->pause_rx = true;
+	priv->pause_tx = true;
+
+	nb8800_mc_init(dev, 0);
+
+	return 0;
+}
+
+static int nb8800_tangox_init(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	u32 pad_mode = PAD_MODE_MII;
+
+	switch (priv->phy_mode) {
+	case PHY_INTERFACE_MODE_MII:
+	case PHY_INTERFACE_MODE_GMII:
+		pad_mode = PAD_MODE_MII;
+		break;
+
+	case PHY_INTERFACE_MODE_RGMII:
+		pad_mode = PAD_MODE_RGMII;
+		break;
+
+	case PHY_INTERFACE_MODE_RGMII_TXID:
+		pad_mode = PAD_MODE_RGMII | PAD_MODE_GTX_CLK_DELAY;
+		break;
+
+	default:
+		dev_err(dev->dev.parent, "unsupported phy mode %s\n",
+			phy_modes(priv->phy_mode));
+		return -EINVAL;
+	}
+
+	nb8800_writeb(priv, NB8800_TANGOX_PAD_MODE, pad_mode);
+
+	return 0;
+}
+
+static int nb8800_tangox_reset(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	int clk_div;
+
+	nb8800_writeb(priv, NB8800_TANGOX_RESET, 0);
+	usleep_range(1000, 10000);
+	nb8800_writeb(priv, NB8800_TANGOX_RESET, 1);
+
+	wmb();		/* ensure reset is cleared before proceeding */
+
+	clk_div = DIV_ROUND_UP(clk_get_rate(priv->clk), 2 * MAX_MDC_CLOCK);
+	nb8800_writew(priv, NB8800_TANGOX_MDIO_CLKDIV, clk_div);
+
+	return 0;
+}
+
+static const struct nb8800_ops nb8800_tangox_ops = {
+	.init	= nb8800_tangox_init,
+	.reset	= nb8800_tangox_reset,
+};
+
+static int nb8800_tango4_init(struct net_device *dev)
+{
+	struct nb8800_priv *priv = netdev_priv(dev);
+	int err;
+
+	err = nb8800_tangox_init(dev);
+	if (err)
+		return err;
+
+	/* On tango4 interrupt on DMA completion per frame works and gives
+	 * better performance despite generating more rx interrupts.
+	 */
+
+	/* Disable unnecessary interrupt on rx completion */
+	nb8800_clearl(priv, NB8800_RXC_CR, RCR_RFI(7));
+
+	/* Request interrupt on descriptor DMA completion */
+	priv->rx_dma_config |= DESC_ID;
+
+	return 0;
+}
+
+static const struct nb8800_ops nb8800_tango4_ops = {
+	.init	= nb8800_tango4_init,
+	.reset	= nb8800_tangox_reset,
+};
+
+static const struct of_device_id nb8800_dt_ids[] = {
+	{
+		.compatible = "aurora,nb8800",
+	},
+	{
+		.compatible = "sigma,smp8642-ethernet",
+		.data = &nb8800_tangox_ops,
+	},
+	{
+		.compatible = "sigma,smp8734-ethernet",
+		.data = &nb8800_tango4_ops,
+	},
+	{ }
+};
+
+static int nb8800_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *match;
+	const struct nb8800_ops *ops = NULL;
+	struct nb8800_priv *priv;
+	struct resource *res;
+	struct net_device *dev;
+	struct mii_bus *bus;
+	const unsigned char *mac;
+	void __iomem *base;
+	int irq;
+	int ret;
+
+	match = of_match_device(nb8800_dt_ids, &pdev->dev);
+	if (match)
+		ops = match->data;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq <= 0) {
+		dev_err(&pdev->dev, "No IRQ\n");
+		return -EINVAL;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	dev_dbg(&pdev->dev, "AU-NB8800 Ethernet at %pa\n", &res->start);
+
+	dev = alloc_etherdev(sizeof(*priv));
+	if (!dev)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, dev);
+	SET_NETDEV_DEV(dev, &pdev->dev);
+
+	priv = netdev_priv(dev);
+	priv->base = base;
+
+	priv->phy_mode = of_get_phy_mode(pdev->dev.of_node);
+	if (priv->phy_mode < 0)
+		priv->phy_mode = PHY_INTERFACE_MODE_RGMII;
+
+	priv->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(priv->clk)) {
+		dev_err(&pdev->dev, "failed to get clock\n");
+		ret = PTR_ERR(priv->clk);
+		goto err_free_dev;
+	}
+
+	ret = clk_prepare_enable(priv->clk);
+	if (ret)
+		goto err_free_dev;
+
+	spin_lock_init(&priv->tx_lock);
+
+	if (ops && ops->reset) {
+		ret = ops->reset(dev);
+		if (ret)
+			goto err_free_dev;
+	}
+
+	bus = devm_mdiobus_alloc(&pdev->dev);
+	if (!bus) {
+		ret = -ENOMEM;
+		goto err_disable_clk;
+	}
+
+	bus->name = "nb8800-mii";
+	bus->read = nb8800_mdio_read;
+	bus->write = nb8800_mdio_write;
+	bus->parent = &pdev->dev;
+	snprintf(bus->id, MII_BUS_ID_SIZE, "%lx.nb8800-mii",
+		 (unsigned long)res->start);
+	bus->priv = priv;
+
+	ret = of_mdiobus_register(bus, pdev->dev.of_node);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register MII bus\n");
+		goto err_disable_clk;
+	}
+
+	priv->phy_node = of_parse_phandle(pdev->dev.of_node, "phy-handle", 0);
+	if (!priv->phy_node) {
+		dev_err(&pdev->dev, "no PHY specified\n");
+		ret = -ENODEV;
+		goto err_free_bus;
+	}
+
+	priv->mii_bus = bus;
+
+	ret = nb8800_hw_init(dev);
+	if (ret)
+		goto err_free_bus;
+
+	if (ops && ops->init) {
+		ret = ops->init(dev);
+		if (ret)
+			goto err_free_bus;
+	}
+
+	dev->netdev_ops = &nb8800_netdev_ops;
+	dev->ethtool_ops = &nb8800_ethtool_ops;
+	dev->flags |= IFF_MULTICAST;
+	dev->irq = irq;
+
+	mac = of_get_mac_address(pdev->dev.of_node);
+	if (mac)
+		ether_addr_copy(dev->dev_addr, mac);
+
+	if (!is_valid_ether_addr(dev->dev_addr))
+		eth_hw_addr_random(dev);
+
+	nb8800_update_mac_addr(dev);
+
+	netif_carrier_off(dev);
+
+	ret = register_netdev(dev);
+	if (ret) {
+		netdev_err(dev, "failed to register netdev\n");
+		goto err_free_dma;
+	}
+
+	netif_napi_add(dev, &priv->napi, nb8800_poll, NAPI_POLL_WEIGHT);
+
+	netdev_info(dev, "MAC address %pM\n", dev->dev_addr);
+
+	return 0;
+
+err_free_dma:
+	nb8800_dma_free(dev);
+err_free_bus:
+	mdiobus_unregister(bus);
+err_disable_clk:
+	clk_disable_unprepare(priv->clk);
+err_free_dev:
+	free_netdev(dev);
+
+	return ret;
+}
+
+static int nb8800_remove(struct platform_device *pdev)
+{
+	struct net_device *ndev = platform_get_drvdata(pdev);
+	struct nb8800_priv *priv = netdev_priv(ndev);
+
+	unregister_netdev(ndev);
+
+	mdiobus_unregister(priv->mii_bus);
+
+	clk_disable_unprepare(priv->clk);
+
+	nb8800_dma_free(ndev);
+	free_netdev(ndev);
+
+	return 0;
+}
+
+static struct platform_driver nb8800_driver = {
+	.driver = {
+		.name		= "nb8800",
+		.of_match_table	= nb8800_dt_ids,
+	},
+	.probe	= nb8800_probe,
+	.remove	= nb8800_remove,
+};
+
+module_platform_driver(nb8800_driver);
+
+MODULE_DESCRIPTION("Aurora AU-NB8800 Ethernet driver");
+MODULE_AUTHOR("Mans Rullgard <mans@mansr.com>");
+MODULE_LICENSE("GPL");

drivers/net/ethernet/aurora/nb8800.h

+#ifndef _NB8800_H_
+#define _NB8800_H_
+
+#include <linux/types.h>
+#include <linux/skbuff.h>
+#include <linux/phy.h>
+#include <linux/clk.h>
+#include <linux/bitops.h>
+
+#define RX_DESC_COUNT			256
+#define TX_DESC_COUNT			256
+
+#define NB8800_DESC_LOW			4
+
+#define RX_BUF_SIZE			1552
+
+#define RX_COPYBREAK			256
+#define RX_COPYHDR			128
+
+#define MAX_MDC_CLOCK			2500000
+
+/* Stargate Solutions SSN8800 core registers */
+#define NB8800_TX_CTL1			0x000
+#define TX_TPD				BIT(5)
+#define TX_APPEND_FCS			BIT(4)
+#define TX_PAD_EN			BIT(3)
+#define TX_RETRY_EN			BIT(2)
+#define TX_EN				BIT(0)
+
+#define NB8800_TX_CTL2			0x001
+
+#define NB8800_RX_CTL			0x004
+#define RX_BC_DISABLE			BIT(7)
+#define RX_RUNT				BIT(6)
+#define RX_AF_EN			BIT(5)
+#define RX_PAUSE_EN			BIT(3)
+#define RX_SEND_CRC			BIT(2)
+#define RX_PAD_STRIP			BIT(1)
+#define RX_EN				BIT(0)
+
+#define NB8800_RANDOM_SEED		0x008
+#define NB8800_TX_SDP			0x14
+#define NB8800_TX_TPDP1			0x18
+#define NB8800_TX_TPDP2			0x19
+#define NB8800_SLOT_TIME		0x1c
+
+#define NB8800_MDIO_CMD			0x020
+#define MDIO_CMD_GO			BIT(31)
+#define MDIO_CMD_WR			BIT(26)
+#define MDIO_CMD_ADDR(x)		((x) << 21)
+#define MDIO_CMD_REG(x)			((x) << 16)
+#define MDIO_CMD_DATA(x)		((x) <<	 0)
+
+#define NB8800_MDIO_STS			0x024
+#define MDIO_STS_ERR			BIT(31)
+
+#define NB8800_MC_ADDR(i)		(0x028 + (i))
+#define NB8800_MC_INIT			0x02e
+#define NB8800_UC_ADDR(i)		(0x03c + (i))
+
+#define NB8800_MAC_MODE			0x044
+#define RGMII_MODE			BIT(7)
+#define HALF_DUPLEX			BIT(4)
+#define BURST_EN			BIT(3)
+#define LOOPBACK_EN			BIT(2)
+#define GMAC_MODE			BIT(0)
+
+#define NB8800_IC_THRESHOLD		0x050
+#define NB8800_PE_THRESHOLD		0x051
+#define NB8800_PF_THRESHOLD		0x052
+#define NB8800_TX_BUFSIZE		0x054
+#define NB8800_FIFO_CTL			0x056
+#define NB8800_PQ1			0x060
+#define NB8800_PQ2			0x061
+#define NB8800_SRC_ADDR(i)		(0x06a + (i))
+#define NB8800_STAT_DATA		0x078
+#define NB8800_STAT_INDEX		0x07c
+#define NB8800_STAT_CLEAR		0x07d
+
+#define NB8800_SLEEP_MODE		0x07e
+#define SLEEP_MODE			BIT(0)
+
+#define NB8800_WAKEUP			0x07f
+#define WAKEUP				BIT(0)
+
+/* Aurora NB8800 host interface registers */
+#define NB8800_TXC_CR			0x100
+#define TCR_LK				BIT(12)
+#define TCR_DS				BIT(11)
+#define TCR_BTS(x)			(((x) & 0x7) << 8)
+#define TCR_DIE				BIT(7)
+#define TCR_TFI(x)			(((x) & 0x7) << 4)
+#define TCR_LE				BIT(3)
+#define TCR_RS				BIT(2)
+#define TCR_DM				BIT(1)
+#define TCR_EN				BIT(0)
+
+#define NB8800_TXC_SR			0x104
+#define TSR_DE				BIT(3)
+#define TSR_DI				BIT(2)
+#define TSR_TO				BIT(1)
+#define TSR_TI				BIT(0)
+
+#define NB8800_TX_SAR			0x108
+#define NB8800_TX_DESC_ADDR		0x10c
+
+#define NB8800_TX_REPORT_ADDR		0x110
+#define TX_BYTES_TRANSFERRED(x)		(((x) >> 16) & 0xffff)
+#define TX_FIRST_DEFERRAL		BIT(7)
+#define TX_EARLY_COLLISIONS(x)		(((x) >> 3) & 0xf)
+#define TX_LATE_COLLISION		BIT(2)
+#define TX_PACKET_DROPPED		BIT(1)
+#define TX_FIFO_UNDERRUN		BIT(0)
+#define IS_TX_ERROR(r)			((r) & 0x07)
+
+#define NB8800_TX_FIFO_SR		0x114
+#define NB8800_TX_ITR			0x118
+
+#define NB8800_RXC_CR			0x200
+#define RCR_FL				BIT(13)
+#define RCR_LK				BIT(12)
+#define RCR_DS				BIT(11)
+#define RCR_BTS(x)			(((x) & 7) << 8)
+#define RCR_DIE				BIT(7)
+#define RCR_RFI(x)			(((x) & 7) << 4)
+#define RCR_LE				BIT(3)
+#define RCR_RS				BIT(2)
+#define RCR_DM				BIT(1)
+#define RCR_EN				BIT(0)
+
+#define NB8800_RXC_SR			0x204
+#define RSR_DE				BIT(3)
+#define RSR_DI				BIT(2)
+#define RSR_RO				BIT(1)
+#define RSR_RI				BIT(0)
+
+#define NB8800_RX_SAR			0x208
+#define NB8800_RX_DESC_ADDR		0x20c
+
+#define NB8800_RX_REPORT_ADDR		0x210
+#define RX_BYTES_TRANSFERRED(x)		(((x) >> 16) & 0xFFFF)
+#define RX_MULTICAST_PKT		BIT(9)
+#define RX_BROADCAST_PKT		BIT(8)
+#define RX_LENGTH_ERR			BIT(7)
+#define RX_FCS_ERR			BIT(6)
+#define RX_RUNT_PKT			BIT(5)
+#define RX_FIFO_OVERRUN			BIT(4)
+#define RX_LATE_COLLISION		BIT(3)
+#define RX_ALIGNMENT_ERROR		BIT(2)
+#define RX_ERROR_MASK			0xfc
+#define IS_RX_ERROR(r)			((r) & RX_ERROR_MASK)
+
+#define NB8800_RX_FIFO_SR		0x214
+#define NB8800_RX_ITR			0x218
+
+/* Sigma Designs SMP86xx additional registers */
+#define NB8800_TANGOX_PAD_MODE		0x400
+#define PAD_MODE_MASK			0x7
+#define PAD_MODE_MII			0x0
+#define PAD_MODE_RGMII			0x1
+#define PAD_MODE_GTX_CLK_INV		BIT(3)
+#define PAD_MODE_GTX_CLK_DELAY		BIT(4)
+
+#define NB8800_TANGOX_MDIO_CLKDIV	0x420
+#define NB8800_TANGOX_RESET		0x424
+
+/* Hardware DMA descriptor */
+struct nb8800_dma_desc {
+	u32				s_addr;	/* start address */
+	u32				n_addr;	/* next descriptor address */
+	u32				r_addr;	/* report address */
+	u32				config;
+} __aligned(8);
+
+#define DESC_ID				BIT(23)
+#define DESC_EOC			BIT(22)
+#define DESC_EOF			BIT(21)
+#define DESC_LK				BIT(20)
+#define DESC_DS				BIT(19)
+#define DESC_BTS(x)			(((x) & 0x7) << 16)
+
+/* DMA descriptor and associated data for rx.
+ * Allocated from coherent memory.
+ */
+struct nb8800_rx_desc {
+	/* DMA descriptor */
+	struct nb8800_dma_desc		desc;
+
+	/* Status report filled in by hardware */
+	u32				report;
+};
+
+/* Address of buffer on rx ring */
+struct nb8800_rx_buf {
+	struct page			*page;
+	unsigned long			offset;
+};
+
+/* DMA descriptors and associated data for tx.
+ * Allocated from coherent memory.
+ */
+struct nb8800_tx_desc {
+	/* DMA descriptor.  The second descriptor is used if packet
+	 * data is unaligned.
+	 */
+	struct nb8800_dma_desc		desc[2];
+
+	/* Status report filled in by hardware */
+	u32				report;
+
+	/* Bounce buffer for initial unaligned part of packet */
+	u8				buf[8] __aligned(8);
+};
+
+/* Packet in tx queue */
+struct nb8800_tx_buf {
+	/* Currently queued skb */
+	struct sk_buff			*skb;
+
+	/* DMA address of the first descriptor */
+	dma_addr_t			dma_desc;
+
+	/* DMA address of packet data */
+	dma_addr_t			dma_addr;
+
+	/* Length of DMA mapping, less than skb->len if alignment
+	 * buffer is used.
+	 */
+	unsigned int			dma_len;
+
+	/* Number of packets in chain starting here */
+	unsigned int			chain_len;
+
+	/* Packet chain ready to be submitted to hardware */
+	bool				ready;
+};
+
+struct nb8800_priv {
+	struct napi_struct		napi;
+
+	void __iomem			*base;
+
+	/* RX DMA descriptors */
+	struct nb8800_rx_desc		*rx_descs;
+
+	/* RX buffers referenced by DMA descriptors */
+	struct nb8800_rx_buf		*rx_bufs;
+
+	/* Current end of chain */
+	u32				rx_eoc;
+
+	/* Value for rx interrupt time register in NAPI interrupt mode */
+	u32				rx_itr_irq;
+
+	/* Value for rx interrupt time register in NAPI poll mode */
+	u32				rx_itr_poll;
+
+	/* Value for config field of rx DMA descriptors */
+	u32				rx_dma_config;
+
+	/* TX DMA descriptors */
+	struct nb8800_tx_desc		*tx_descs;
+
+	/* TX packet queue */
+	struct nb8800_tx_buf		*tx_bufs;
+
+	/* Number of free tx queue entries */
+	atomic_t			tx_free;
+
+	/* First free tx queue entry */
+	u32				tx_next;
+
+	/* Next buffer to transmit */
+	u32				tx_queue;
+
+	/* Start of current packet chain */
+	struct nb8800_tx_buf		*tx_chain;
+
+	/* Next buffer to reclaim */
+	u32				tx_done;
+
+	/* Lock for DMA activation */
+	spinlock_t			tx_lock;
+
+	struct mii_bus			*mii_bus;
+	struct device_node		*phy_node;
+	struct phy_device		*phydev;
+
+	/* PHY connection type from DT */
+	int				phy_mode;
+
+	/* Current link status */
+	int				speed;
+	int				duplex;
+	int				link;
+
+	/* Pause settings */
+	bool				pause_aneg;
+	bool				pause_rx;
+	bool				pause_tx;
+
+	/* DMA base address of rx descriptors, see rx_descs above */
+	dma_addr_t			rx_desc_dma;
+
+	/* DMA base address of tx descriptors, see tx_descs above */
+	dma_addr_t			tx_desc_dma;
+
+	struct clk			*clk;
+};
+
+struct nb8800_ops {
+	int				(*init)(struct net_device *dev);
+	int				(*reset)(struct net_device *dev);
+};
+
+#endif /* _NB8800_H_ */