net: Add support for the OpenCores 10/100 Mbps Ethernet MAC.

This patch adds a platform device driver that supports the OpenCores 10/100
Mbps Ethernet MAC.

The driver expects three resources: one IORESOURCE_MEM resource defines the
memory region for the core's memory-mapped registers while a second
IORESOURCE_MEM resource defines the network packet buffer space. The third
resource, of type IORESOURCE_IRQ, associates an interrupt with the driver.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 1121 insertions, 0 deletions

diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index e5ffc1c606c..f062b424704 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -972,6 +972,14 @@ config ENC28J60_WRITEVERIFY
           Enable the verify after the buffer write useful for debugging purpose.
           If unsure, say N.
 
+config ETHOC
+        tristate "OpenCores 10/100 Mbps Ethernet MAC support"
+        depends on NET_ETHERNET
+        select MII
+        select PHYLIB
+        help
+          Say Y here if you want to use the OpenCores 10/100 Mbps Ethernet MAC.
+
 config SMC911X
         tristate "SMSC LAN911[5678] support"
         select CRC32
diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index 758ecdf4c82..98409c9dd44 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -230,6 +230,7 @@ obj-$(CONFIG_PASEMI_MAC) += pasemi_mac_driver.o
 pasemi_mac_driver-objs := pasemi_mac.o pasemi_mac_ethtool.o
 obj-$(CONFIG_MLX4_CORE) += mlx4/
 obj-$(CONFIG_ENC28J60) += enc28j60.o
+obj-$(CONFIG_ETHOC) += ethoc.o
 
 obj-$(CONFIG_XTENSA_XT2000_SONIC) += xtsonic.o
 
diff --git a/drivers/net/ethoc.c b/drivers/net/ethoc.c
new file mode 100644
index 00000000000..91a9b1a3376
--- /dev/null
+++ b/drivers/net/ethoc.c
@@ -0,0 +1,1112 @@
+/*
+ * linux/drivers/net/ethoc.c
+ *
+ * Copyright (C) 2007-2008 Avionic Design Development GmbH
+ * Copyright (C) 2008-2009 Avionic Design GmbH
+ *
+ * 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.
+ *
+ * Written by Thierry Reding <thierry.reding@avionic-design.de>
+ */
+
+#include <linux/etherdevice.h>
+#include <linux/crc32.h>
+#include <linux/io.h>
+#include <linux/mii.h>
+#include <linux/phy.h>
+#include <linux/platform_device.h>
+#include <net/ethoc.h>
+
+/* register offsets */
+#define MODER           0x00
+#define INT_SOURCE      0x04
+#define INT_MASK        0x08
+#define IPGT            0x0c
+#define IPGR1           0x10
+#define IPGR2           0x14
+#define PACKETLEN       0x18
+#define COLLCONF        0x1c
+#define TX_BD_NUM       0x20
+#define CTRLMODER       0x24
+#define MIIMODER        0x28
+#define MIICOMMAND      0x2c
+#define MIIADDRESS      0x30
+#define MIITX_DATA      0x34
+#define MIIRX_DATA      0x38
+#define MIISTATUS       0x3c
+#define MAC_ADDR0       0x40
+#define MAC_ADDR1       0x44
+#define ETH_HASH0       0x48
+#define ETH_HASH1       0x4c
+#define ETH_TXCTRL      0x50
+
+/* mode register */
+#define MODER_RXEN      (1 <<  0) /* receive enable */
+#define MODER_TXEN      (1 <<  1) /* transmit enable */
+#define MODER_NOPRE     (1 <<  2) /* no preamble */
+#define MODER_BRO       (1 <<  3) /* broadcast address */
+#define MODER_IAM       (1 <<  4) /* individual address mode */
+#define MODER_PRO       (1 <<  5) /* promiscuous mode */
+#define MODER_IFG       (1 <<  6) /* interframe gap for incoming frames */
+#define MODER_LOOP      (1 <<  7) /* loopback */
+#define MODER_NBO       (1 <<  8) /* no back-off */
+#define MODER_EDE       (1 <<  9) /* excess defer enable */
+#define MODER_FULLD     (1 << 10) /* full duplex */
+#define MODER_RESET     (1 << 11) /* FIXME: reset (undocumented) */
+#define MODER_DCRC      (1 << 12) /* delayed CRC enable */
+#define MODER_CRC       (1 << 13) /* CRC enable */
+#define MODER_HUGE      (1 << 14) /* huge packets enable */
+#define MODER_PAD       (1 << 15) /* padding enabled */
+#define MODER_RSM       (1 << 16) /* receive small packets */
+
+/* interrupt source and mask registers */
+#define INT_MASK_TXF    (1 << 0) /* transmit frame */
+#define INT_MASK_TXE    (1 << 1) /* transmit error */
+#define INT_MASK_RXF    (1 << 2) /* receive frame */
+#define INT_MASK_RXE    (1 << 3) /* receive error */
+#define INT_MASK_BUSY   (1 << 4)
+#define INT_MASK_TXC    (1 << 5) /* transmit control frame */
+#define INT_MASK_RXC    (1 << 6) /* receive control frame */
+
+#define INT_MASK_TX     (INT_MASK_TXF | INT_MASK_TXE)
+#define INT_MASK_RX     (INT_MASK_RXF | INT_MASK_RXE)
+
+#define INT_MASK_ALL ( \
+                INT_MASK_TXF | INT_MASK_TXE | \
+                INT_MASK_RXF | INT_MASK_RXE | \
+                INT_MASK_TXC | INT_MASK_RXC | \
+                INT_MASK_BUSY \
+        )
+
+/* packet length register */
+#define PACKETLEN_MIN(min)              (((min) & 0xffff) << 16)
+#define PACKETLEN_MAX(max)              (((max) & 0xffff) <<  0)
+#define PACKETLEN_MIN_MAX(min, max)     (PACKETLEN_MIN(min) | \
+                                        PACKETLEN_MAX(max))
+
+/* transmit buffer number register */
+#define TX_BD_NUM_VAL(x)        (((x) <= 0x80) ? (x) : 0x80)
+
+/* control module mode register */
+#define CTRLMODER_PASSALL       (1 << 0) /* pass all receive frames */
+#define CTRLMODER_RXFLOW        (1 << 1) /* receive control flow */
+#define CTRLMODER_TXFLOW        (1 << 2) /* transmit control flow */
+
+/* MII mode register */
+#define MIIMODER_CLKDIV(x)      ((x) & 0xfe) /* needs to be an even number */
+#define MIIMODER_NOPRE          (1 << 8) /* no preamble */
+
+/* MII command register */
+#define MIICOMMAND_SCAN         (1 << 0) /* scan status */
+#define MIICOMMAND_READ         (1 << 1) /* read status */
+#define MIICOMMAND_WRITE        (1 << 2) /* write control data */
+
+/* MII address register */
+#define MIIADDRESS_FIAD(x)              (((x) & 0x1f) << 0)
+#define MIIADDRESS_RGAD(x)              (((x) & 0x1f) << 8)
+#define MIIADDRESS_ADDR(phy, reg)       (MIIADDRESS_FIAD(phy) | \
+                                        MIIADDRESS_RGAD(reg))
+
+/* MII transmit data register */
+#define MIITX_DATA_VAL(x)       ((x) & 0xffff)
+
+/* MII receive data register */
+#define MIIRX_DATA_VAL(x)       ((x) & 0xffff)
+
+/* MII status register */
+#define MIISTATUS_LINKFAIL      (1 << 0)
+#define MIISTATUS_BUSY          (1 << 1)
+#define MIISTATUS_INVALID       (1 << 2)
+
+/* TX buffer descriptor */
+#define TX_BD_CS                (1 <<  0) /* carrier sense lost */
+#define TX_BD_DF                (1 <<  1) /* defer indication */
+#define TX_BD_LC                (1 <<  2) /* late collision */
+#define TX_BD_RL                (1 <<  3) /* retransmission limit */
+#define TX_BD_RETRY_MASK        (0x00f0)
+#define TX_BD_RETRY(x)          (((x) & 0x00f0) >>  4)
+#define TX_BD_UR                (1 <<  8) /* transmitter underrun */
+#define TX_BD_CRC               (1 << 11) /* TX CRC enable */
+#define TX_BD_PAD               (1 << 12) /* pad enable for short packets */
+#define TX_BD_WRAP              (1 << 13)
+#define TX_BD_IRQ               (1 << 14) /* interrupt request enable */
+#define TX_BD_READY             (1 << 15) /* TX buffer ready */
+#define TX_BD_LEN(x)            (((x) & 0xffff) << 16)
+#define TX_BD_LEN_MASK          (0xffff << 16)
+
+#define TX_BD_STATS             (TX_BD_CS | TX_BD_DF | TX_BD_LC | \
+                                TX_BD_RL | TX_BD_RETRY_MASK | TX_BD_UR)
+
+/* RX buffer descriptor */
+#define RX_BD_LC        (1 <<  0) /* late collision */
+#define RX_BD_CRC       (1 <<  1) /* RX CRC error */
+#define RX_BD_SF        (1 <<  2) /* short frame */
+#define RX_BD_TL        (1 <<  3) /* too long */
+#define RX_BD_DN        (1 <<  4) /* dribble nibble */
+#define RX_BD_IS        (1 <<  5) /* invalid symbol */
+#define RX_BD_OR        (1 <<  6) /* receiver overrun */
+#define RX_BD_MISS      (1 <<  7)
+#define RX_BD_CF        (1 <<  8) /* control frame */
+#define RX_BD_WRAP      (1 << 13)
+#define RX_BD_IRQ       (1 << 14) /* interrupt request enable */
+#define RX_BD_EMPTY     (1 << 15)
+#define RX_BD_LEN(x)    (((x) & 0xffff) << 16)
+
+#define RX_BD_STATS     (RX_BD_LC | RX_BD_CRC | RX_BD_SF | RX_BD_TL | \
+                        RX_BD_DN | RX_BD_IS | RX_BD_OR | RX_BD_MISS)
+
+#define ETHOC_BUFSIZ            1536
+#define ETHOC_ZLEN              64
+#define ETHOC_BD_BASE           0x400
+#define ETHOC_TIMEOUT           (HZ / 2)
+#define ETHOC_MII_TIMEOUT       (1 + (HZ / 5))
+
+/**
+ * struct ethoc - driver-private device structure
+ * @iobase:     pointer to I/O memory region
+ * @membase:    pointer to buffer memory region
+ * @num_tx:     number of send buffers
+ * @cur_tx:     last send buffer written
+ * @dty_tx:     last buffer actually sent
+ * @num_rx:     number of receive buffers
+ * @cur_rx:     current receive buffer
+ * @netdev:     pointer to network device structure
+ * @napi:       NAPI structure
+ * @stats:      network device statistics
+ * @msg_enable: device state flags
+ * @rx_lock:    receive lock
+ * @lock:       device lock
+ * @phy:        attached PHY
+ * @mdio:       MDIO bus for PHY access
+ * @phy_id:     address of attached PHY
+ */
+struct ethoc {
+        void __iomem *iobase;
+        void __iomem *membase;
+
+        unsigned int num_tx;
+        unsigned int cur_tx;
+        unsigned int dty_tx;
+
+        unsigned int num_rx;
+        unsigned int cur_rx;
+
+        struct net_device *netdev;
+        struct napi_struct napi;
+        struct net_device_stats stats;
+        u32 msg_enable;
+
+        spinlock_t rx_lock;
+        spinlock_t lock;
+
+        struct phy_device *phy;
+        struct mii_bus *mdio;
+        s8 phy_id;
+};
+
+/**
+ * struct ethoc_bd - buffer descriptor
+ * @stat:       buffer statistics
+ * @addr:       physical memory address
+ */
+struct ethoc_bd {
+        u32 stat;
+        u32 addr;
+};
+
+static u32 ethoc_read(struct ethoc *dev, loff_t offset)
+{
+        return ioread32(dev->iobase + offset);
+}
+
+static void ethoc_write(struct ethoc *dev, loff_t offset, u32 data)
+{
+        iowrite32(data, dev->iobase + offset);
+}
+
+static void ethoc_read_bd(struct ethoc *dev, int index, struct ethoc_bd *bd)
+{
+        loff_t offset = ETHOC_BD_BASE + (index * sizeof(struct ethoc_bd));
+        bd->stat = ethoc_read(dev, offset + 0);
+        bd->addr = ethoc_read(dev, offset + 4);
+}
+
+static void ethoc_write_bd(struct ethoc *dev, int index,
+                const struct ethoc_bd *bd)
+{
+        loff_t offset = ETHOC_BD_BASE + (index * sizeof(struct ethoc_bd));
+        ethoc_write(dev, offset + 0, bd->stat);
+        ethoc_write(dev, offset + 4, bd->addr);
+}
+
+static void ethoc_enable_irq(struct ethoc *dev, u32 mask)
+{
+        u32 imask = ethoc_read(dev, INT_MASK);
+        imask |= mask;
+        ethoc_write(dev, INT_MASK, imask);
+}
+
+static void ethoc_disable_irq(struct ethoc *dev, u32 mask)
+{
+        u32 imask = ethoc_read(dev, INT_MASK);
+        imask &= ~mask;
+        ethoc_write(dev, INT_MASK, imask);
+}
+
+static void ethoc_ack_irq(struct ethoc *dev, u32 mask)
+{
+        ethoc_write(dev, INT_SOURCE, mask);
+}
+
+static void ethoc_enable_rx_and_tx(struct ethoc *dev)
+{
+        u32 mode = ethoc_read(dev, MODER);
+        mode |= MODER_RXEN | MODER_TXEN;
+        ethoc_write(dev, MODER, mode);
+}
+
+static void ethoc_disable_rx_and_tx(struct ethoc *dev)
+{
+        u32 mode = ethoc_read(dev, MODER);
+        mode &= ~(MODER_RXEN | MODER_TXEN);
+        ethoc_write(dev, MODER, mode);
+}
+
+static int ethoc_init_ring(struct ethoc *dev)
+{
+        struct ethoc_bd bd;
+        int i;
+
+        dev->cur_tx = 0;
+        dev->dty_tx = 0;
+        dev->cur_rx = 0;
+
+        /* setup transmission buffers */
+        bd.addr = 0;
+        bd.stat = TX_BD_IRQ | TX_BD_CRC;
+
+        for (i = 0; i < dev->num_tx; i++) {
+                if (i == dev->num_tx - 1)
+                        bd.stat |= TX_BD_WRAP;
+
+                ethoc_write_bd(dev, i, &bd);
+                bd.addr += ETHOC_BUFSIZ;
+        }
+
+        bd.addr = dev->num_tx * ETHOC_BUFSIZ;
+        bd.stat = RX_BD_EMPTY | RX_BD_IRQ;
+
+        for (i = 0; i < dev->num_rx; i++) {
+                if (i == dev->num_rx - 1)
+                        bd.stat |= RX_BD_WRAP;
+
+                ethoc_write_bd(dev, dev->num_tx + i, &bd);
+                bd.addr += ETHOC_BUFSIZ;
+        }
+
+        return 0;
+}
+
+static int ethoc_reset(struct ethoc *dev)
+{
+        u32 mode;
+
+        /* TODO: reset controller? */
+
+        ethoc_disable_rx_and_tx(dev);
+
+        /* TODO: setup registers */
+
+        /* enable FCS generation and automatic padding */
+        mode = ethoc_read(dev, MODER);
+        mode |= MODER_CRC | MODER_PAD;
+        ethoc_write(dev, MODER, mode);
+
+        /* set full-duplex mode */
+        mode = ethoc_read(dev, MODER);
+        mode |= MODER_FULLD;
+        ethoc_write(dev, MODER, mode);
+        ethoc_write(dev, IPGT, 0x15);
+
+        ethoc_ack_irq(dev, INT_MASK_ALL);
+        ethoc_enable_irq(dev, INT_MASK_ALL);
+        ethoc_enable_rx_and_tx(dev);
+        return 0;
+}
+
+static unsigned int ethoc_update_rx_stats(struct ethoc *dev,
+                struct ethoc_bd *bd)
+{
+        struct net_device *netdev = dev->netdev;
+        unsigned int ret = 0;
+
+        if (bd->stat & RX_BD_TL) {
+                dev_err(&netdev->dev, "RX: frame too long\n");
+                dev->stats.rx_length_errors++;
+                ret++;
+        }
+
+        if (bd->stat & RX_BD_SF) {
+                dev_err(&netdev->dev, "RX: frame too short\n");
+                dev->stats.rx_length_errors++;
+                ret++;
+        }
+
+        if (bd->stat & RX_BD_DN) {
+                dev_err(&netdev->dev, "RX: dribble nibble\n");
+                dev->stats.rx_frame_errors++;
+        }
+
+        if (bd->stat & RX_BD_CRC) {
+                dev_err(&netdev->dev, "RX: wrong CRC\n");
+                dev->stats.rx_crc_errors++;
+                ret++;
+        }
+
+        if (bd->stat & RX_BD_OR) {
+                dev_err(&netdev->dev, "RX: overrun\n");
+                dev->stats.rx_over_errors++;
+                ret++;
+        }
+
+        if (bd->stat & RX_BD_MISS)
+                dev->stats.rx_missed_errors++;
+
+        if (bd->stat & RX_BD_LC) {
+                dev_err(&netdev->dev, "RX: late collision\n");
+                dev->stats.collisions++;
+                ret++;
+        }
+
+        return ret;
+}
+
+static int ethoc_rx(struct net_device *dev, int limit)
+{
+        struct ethoc *priv = netdev_priv(dev);
+        int count;
+
+        for (count = 0; count < limit; ++count) {
+                unsigned int entry;
+                struct ethoc_bd bd;
+
+                entry = priv->num_tx + (priv->cur_rx % priv->num_rx);
+                ethoc_read_bd(priv, entry, &bd);
+                if (bd.stat & RX_BD_EMPTY)
+                        break;
+
+                if (ethoc_update_rx_stats(priv, &bd) == 0) {
+                        int size = bd.stat >> 16;
+                        struct sk_buff *skb = netdev_alloc_skb(dev, size);
+                        if (likely(skb)) {
+                                void *src = priv->membase + bd.addr;
+                                memcpy_fromio(skb_put(skb, size), src, size);
+                                skb->protocol = eth_type_trans(skb, dev);
+                                dev->last_rx = jiffies;
+                                priv->stats.rx_packets++;
+                                priv->stats.rx_bytes += size;
+                                netif_receive_skb(skb);
+                        } else {
+                                if (net_ratelimit())
+                                        dev_warn(&dev->dev, "low on memory - "
+                                                        "packet dropped\n");
+
+                                priv->stats.rx_dropped++;
+                                break;
+                        }
+                }
+
+                /* clear the buffer descriptor so it can be reused */
+                bd.stat &= ~RX_BD_STATS;
+                bd.stat |=  RX_BD_EMPTY;
+                ethoc_write_bd(priv, entry, &bd);
+                priv->cur_rx++;
+        }
+
+        return count;
+}
+
+static int ethoc_update_tx_stats(struct ethoc *dev, struct ethoc_bd *bd)
+{
+        struct net_device *netdev = dev->netdev;
+
+        if (bd->stat & TX_BD_LC) {
+                dev_err(&netdev->dev, "TX: late collision\n");
+                dev->stats.tx_window_errors++;
+        }
+
+        if (bd->stat & TX_BD_RL) {
+                dev_err(&netdev->dev, "TX: retransmit limit\n");
+                dev->stats.tx_aborted_errors++;
+        }
+
+        if (bd->stat & TX_BD_UR) {
+                dev_err(&netdev->dev, "TX: underrun\n");
+                dev->stats.tx_fifo_errors++;
+        }
+
+        if (bd->stat & TX_BD_CS) {
+                dev_err(&netdev->dev, "TX: carrier sense lost\n");
+                dev->stats.tx_carrier_errors++;
+        }
+
+        if (bd->stat & TX_BD_STATS)
+                dev->stats.tx_errors++;
+
+        dev->stats.collisions += (bd->stat >> 4) & 0xf;
+        dev->stats.tx_bytes += bd->stat >> 16;
+        dev->stats.tx_packets++;
+        return 0;
+}
+
+static void ethoc_tx(struct net_device *dev)
+{
+        struct ethoc *priv = netdev_priv(dev);
+
+        spin_lock(&priv->lock);
+
+        while (priv->dty_tx != priv->cur_tx) {
+                unsigned int entry = priv->dty_tx % priv->num_tx;
+                struct ethoc_bd bd;
+
+                ethoc_read_bd(priv, entry, &bd);
+                if (bd.stat & TX_BD_READY)
+                        break;
+
+                entry = (++priv->dty_tx) % priv->num_tx;
+                (void)ethoc_update_tx_stats(priv, &bd);
+        }
+
+        if ((priv->cur_tx - priv->dty_tx) <= (priv->num_tx / 2))
+                netif_wake_queue(dev);
+
+        ethoc_ack_irq(priv, INT_MASK_TX);
+        spin_unlock(&priv->lock);
+}
+
+static irqreturn_t ethoc_interrupt(int irq, void *dev_id)
+{
+        struct net_device *dev = (struct net_device *)dev_id;
+        struct ethoc *priv = netdev_priv(dev);
+        u32 pending;
+
+        ethoc_disable_irq(priv, INT_MASK_ALL);
+        pending = ethoc_read(priv, INT_SOURCE);
+        if (unlikely(pending == 0)) {
+                ethoc_enable_irq(priv, INT_MASK_ALL);
+                return IRQ_NONE;
+        }
+
+        ethoc_ack_irq(priv, INT_MASK_ALL);
+
+        if (pending & INT_MASK_BUSY) {
+                dev_err(&dev->dev, "packet dropped\n");
+                priv->stats.rx_dropped++;
+        }
+
+        if (pending & INT_MASK_RX) {
+                if (napi_schedule_prep(&priv->napi))
+                        __napi_schedule(&priv->napi);
+        } else {
+                ethoc_enable_irq(priv, INT_MASK_RX);
+        }
+
+        if (pending & INT_MASK_TX)
+                ethoc_tx(dev);
+
+        ethoc_enable_irq(priv, INT_MASK_ALL & ~INT_MASK_RX);
+        return IRQ_HANDLED;
+}
+
+static int ethoc_get_mac_address(struct net_device *dev, void *addr)
+{
+        struct ethoc *priv = netdev_priv(dev);
+        u8 *mac = (u8 *)addr;
+        u32 reg;
+
+        reg = ethoc_read(priv, MAC_ADDR0);
+        mac[2] = (reg >> 24) & 0xff;
+        mac[3] = (reg >> 16) & 0xff;
+        mac[4] = (reg >>  8) & 0xff;
+        mac[5] = (reg >>  0) & 0xff;
+
+        reg = ethoc_read(priv, MAC_ADDR1);
+        mac[0] = (reg >>  8) & 0xff;
+        mac[1] = (reg >>  0) & 0xff;
+
+        return 0;
+}
+
+static int ethoc_poll(struct napi_struct *napi, int budget)
+{
+        struct ethoc *priv = container_of(napi, struct ethoc, napi);
+        int work_done = 0;
+
+        work_done = ethoc_rx(priv->netdev, budget);
+        if (work_done < budget) {
+                ethoc_enable_irq(priv, INT_MASK_RX);
+                napi_complete(napi);
+        }
+
+        return work_done;
+}
+
+static int ethoc_mdio_read(struct mii_bus *bus, int phy, int reg)
+{
+        unsigned long timeout = jiffies + ETHOC_MII_TIMEOUT;
+        struct ethoc *priv = bus->priv;
+
+        ethoc_write(priv, MIIADDRESS, MIIADDRESS_ADDR(phy, reg));
+        ethoc_write(priv, MIICOMMAND, MIICOMMAND_READ);
+
+        while (time_before(jiffies, timeout)) {
+                u32 status = ethoc_read(priv, MIISTATUS);
+                if (!(status & MIISTATUS_BUSY)) {
+                        u32 data = ethoc_read(priv, MIIRX_DATA);
+                        /* reset MII command register */
+                        ethoc_write(priv, MIICOMMAND, 0);
+                        return data;
+                }
+
+                schedule();
+        }
+
+        return -EBUSY;
+}
+
+static int ethoc_mdio_write(struct mii_bus *bus, int phy, int reg, u16 val)
+{
+        unsigned long timeout = jiffies + ETHOC_MII_TIMEOUT;
+        struct ethoc *priv = bus->priv;
+
+        ethoc_write(priv, MIIADDRESS, MIIADDRESS_ADDR(phy, reg));
+        ethoc_write(priv, MIITX_DATA, val);
+        ethoc_write(priv, MIICOMMAND, MIICOMMAND_WRITE);
+
+        while (time_before(jiffies, timeout)) {
+                u32 stat = ethoc_read(priv, MIISTATUS);
+                if (!(stat & MIISTATUS_BUSY))
+                        return 0;
+
+                schedule();
+        }
+
+        return -EBUSY;
+}
+
+static int ethoc_mdio_reset(struct mii_bus *bus)
+{
+        return 0;
+}
+
+static void ethoc_mdio_poll(struct net_device *dev)
+{
+}
+
+static int ethoc_mdio_probe(struct net_device *dev)
+{
+        struct ethoc *priv = netdev_priv(dev);
+        struct phy_device *phy;
+        int i;
+
+        for (i = 0; i < PHY_MAX_ADDR; i++) {
+                phy = priv->mdio->phy_map[i];
+                if (phy) {
+                        if (priv->phy_id != -1) {
+                                /* attach to specified PHY */
+                                if (priv->phy_id == phy->addr)
+                                        break;
+                        } else {
+                                /* autoselect PHY if none was specified */
+                                if (phy->addr != 0)
+                                        break;
+                        }
+                }
+        }
+
+        if (!phy) {
+                dev_err(&dev->dev, "no PHY found\n");
+                return -ENXIO;
+        }
+
+        phy = phy_connect(dev, dev_name(&phy->dev), &ethoc_mdio_poll, 0,
+                        PHY_INTERFACE_MODE_GMII);
+        if (IS_ERR(phy)) {
+                dev_err(&dev->dev, "could not attach to PHY\n");
+                return PTR_ERR(phy);
+        }
+
+        priv->phy = phy;
+        return 0;
+}
+
+static int ethoc_open(struct net_device *dev)
+{
+        struct ethoc *priv = netdev_priv(dev);
+        unsigned int min_tx = 2;
+        unsigned int num_bd;
+        int ret;
+
+        ret = request_irq(dev->irq, ethoc_interrupt, IRQF_SHARED,
+                        dev->name, dev);
+        if (ret)
+                return ret;
+
+        /* calculate the number of TX/RX buffers */
+        num_bd = (dev->mem_end - dev->mem_start + 1) / ETHOC_BUFSIZ;
+        priv->num_tx = min(min_tx, num_bd / 4);
+        priv->num_rx = num_bd - priv->num_tx;
+        ethoc_write(priv, TX_BD_NUM, priv->num_tx);
+
+        ethoc_init_ring(priv);
+        ethoc_reset(priv);
+
+        if (netif_queue_stopped(dev)) {
+                dev_dbg(&dev->dev, " resuming queue\n");
+                netif_wake_queue(dev);
+        } else {
+                dev_dbg(&dev->dev, " starting queue\n");
+                netif_start_queue(dev);
+        }
+
+        phy_start(priv->phy);
+        napi_enable(&priv->napi);
+
+        if (netif_msg_ifup(priv)) {
+                dev_info(&dev->dev, "I/O: %08lx Memory: %08lx-%08lx\n",
+                                dev->base_addr, dev->mem_start, dev->mem_end);
+        }
+
+        return 0;
+}
+
+static int ethoc_stop(struct net_device *dev)
+{
+        struct ethoc *priv = netdev_priv(dev);
+
+        napi_disable(&priv->napi);
+
+        if (priv->phy)
+                phy_stop(priv->phy);
+
+        ethoc_disable_rx_and_tx(priv);
+        free_irq(dev->irq, dev);
+
+        if (!netif_queue_stopped(dev))
+                netif_stop_queue(dev);
+
+        return 0;
+}
+
+static int ethoc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
+{
+        struct ethoc *priv = netdev_priv(dev);
+        struct mii_ioctl_data *mdio = if_mii(ifr);
+        struct phy_device *phy = NULL;
+
+        if (!netif_running(dev))
+                return -EINVAL;
+
+        if (cmd != SIOCGMIIPHY) {
+                if (mdio->phy_id >= PHY_MAX_ADDR)
+                        return -ERANGE;
+
+                phy = priv->mdio->phy_map[mdio->phy_id];
+                if (!phy)
+                        return -ENODEV;
+        } else {
+                phy = priv->phy;
+        }
+
+        return phy_mii_ioctl(phy, mdio, cmd);
+}
+
+static int ethoc_config(struct net_device *dev, struct ifmap *map)
+{
+        return -ENOSYS;
+}
+
+static int ethoc_set_mac_address(struct net_device *dev, void *addr)
+{
+        struct ethoc *priv = netdev_priv(dev);
+        u8 *mac = (u8 *)addr;
+
+        ethoc_write(priv, MAC_ADDR0, (mac[2] << 24) | (mac[3] << 16) |
+                                     (mac[4] <<  8) | (mac[5] <<  0));
+        ethoc_write(priv, MAC_ADDR1, (mac[0] <<  8) | (mac[1] <<  0));
+
+        return 0;
+}
+
+static void ethoc_set_multicast_list(struct net_device *dev)
+{
+        struct ethoc *priv = netdev_priv(dev);
+        u32 mode = ethoc_read(priv, MODER);
+        struct dev_mc_list *mc = NULL;
+        u32 hash[2] = { 0, 0 };
+
+        /* set loopback mode if requested */
+        if (dev->flags & IFF_LOOPBACK)
+                mode |=  MODER_LOOP;
+        else
+                mode &= ~MODER_LOOP;
+
+        /* receive broadcast frames if requested */
+        if (dev->flags & IFF_BROADCAST)
+                mode &= ~MODER_BRO;
+        else
+                mode |=  MODER_BRO;
+
+        /* enable promiscuous mode if requested */
+        if (dev->flags & IFF_PROMISC)
+                mode |=  MODER_PRO;
+        else
+                mode &= ~MODER_PRO;
+
+        ethoc_write(priv, MODER, mode);
+
+        /* receive multicast frames */
+        if (dev->flags & IFF_ALLMULTI) {
+                hash[0] = 0xffffffff;
+                hash[1] = 0xffffffff;
+        } else {
+                for (mc = dev->mc_list; mc; mc = mc->next) {
+                        u32 crc = ether_crc(mc->dmi_addrlen, mc->dmi_addr);
+                        int bit = (crc >> 26) & 0x3f;
+                        hash[bit >> 5] |= 1 << (bit & 0x1f);
+                }
+        }
+
+        ethoc_write(priv, ETH_HASH0, hash[0]);
+        ethoc_write(priv, ETH_HASH1, hash[1]);
+}
+
+static int ethoc_change_mtu(struct net_device *dev, int new_mtu)
+{
+        return -ENOSYS;
+}
+
+static void ethoc_tx_timeout(struct net_device *dev)
+{
+        struct ethoc *priv = netdev_priv(dev);
+        u32 pending = ethoc_read(priv, INT_SOURCE);
+        if (likely(pending))
+                ethoc_interrupt(dev->irq, dev);
+}
+
+static struct net_device_stats *ethoc_stats(struct net_device *dev)
+{
+        struct ethoc *priv = netdev_priv(dev);
+        return &priv->stats;
+}
+
+static int ethoc_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+        struct ethoc *priv = netdev_priv(dev);
+        struct ethoc_bd bd;
+        unsigned int entry;
+        void *dest;
+
+        if (unlikely(skb->len > ETHOC_BUFSIZ)) {
+                priv->stats.tx_errors++;
+                return -EMSGSIZE;
+        }
+
+        entry = priv->cur_tx % priv->num_tx;
+        spin_lock_irq(&priv->lock);
+        priv->cur_tx++;
+
+        ethoc_read_bd(priv, entry, &bd);
+        if (unlikely(skb->len < ETHOC_ZLEN))
+                bd.stat |=  TX_BD_PAD;
+        else
+                bd.stat &= ~TX_BD_PAD;
+
+        dest = priv->membase + bd.addr;
+        memcpy_toio(dest, skb->data, skb->len);
+
+        bd.stat &= ~(TX_BD_STATS | TX_BD_LEN_MASK);
+        bd.stat |= TX_BD_LEN(skb->len);
+        ethoc_write_bd(priv, entry, &bd);
+
+        bd.stat |= TX_BD_READY;
+        ethoc_write_bd(priv, entry, &bd);
+
+        if (priv->cur_tx == (priv->dty_tx + priv->num_tx)) {
+                dev_dbg(&dev->dev, "stopping queue\n");
+                netif_stop_queue(dev);
+        }
+
+        dev->trans_start = jiffies;
+        dev_kfree_skb(skb);
+
+        spin_unlock_irq(&priv->lock);
+        return NETDEV_TX_OK;
+}
+
+static const struct net_device_ops ethoc_netdev_ops = {
+        .ndo_open = ethoc_open,
+        .ndo_stop = ethoc_stop,
+        .ndo_do_ioctl = ethoc_ioctl,
+        .ndo_set_config = ethoc_config,
+        .ndo_set_mac_address = ethoc_set_mac_address,
+        .ndo_set_multicast_list = ethoc_set_multicast_list,
+        .ndo_change_mtu = ethoc_change_mtu,
+        .ndo_tx_timeout = ethoc_tx_timeout,
+        .ndo_get_stats = ethoc_stats,
+        .ndo_start_xmit = ethoc_start_xmit,
+};
+
+/**
+ * ethoc_probe() - initialize OpenCores ethernet MAC
+ * pdev:        platform device
+ */
+static int ethoc_probe(struct platform_device *pdev)
+{
+        struct net_device *netdev = NULL;
+        struct resource *res = NULL;
+        struct resource *mmio = NULL;
+        struct resource *mem = NULL;
+        struct ethoc *priv = NULL;
+        unsigned int phy;
+        int ret = 0;
+
+        /* allocate networking device */
+        netdev = alloc_etherdev(sizeof(struct ethoc));
+        if (!netdev) {
+                dev_err(&pdev->dev, "cannot allocate network device\n");
+                ret = -ENOMEM;
+                goto out;
+        }
+
+        SET_NETDEV_DEV(netdev, &pdev->dev);
+        platform_set_drvdata(pdev, netdev);
+
+        /* obtain I/O memory space */
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!res) {
+                dev_err(&pdev->dev, "cannot obtain I/O memory space\n");
+                ret = -ENXIO;
+                goto free;
+        }
+
+        mmio = devm_request_mem_region(&pdev->dev, res->start,
+                        res->end - res->start + 1, res->name);
+        if (!res) {
+                dev_err(&pdev->dev, "cannot request I/O memory space\n");
+                ret = -ENXIO;
+                goto free;
+        }
+
+        netdev->base_addr = mmio->start;
+
+        /* obtain buffer memory space */
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+        if (!res) {
+                dev_err(&pdev->dev, "cannot obtain memory space\n");
+                ret = -ENXIO;
+                goto free;
+        }
+
+        mem = devm_request_mem_region(&pdev->dev, res->start,
+                        res->end - res->start + 1, res->name);
+        if (!mem) {
+                dev_err(&pdev->dev, "cannot request memory space\n");
+                ret = -ENXIO;
+                goto free;
+        }
+
+        netdev->mem_start = mem->start;
+        netdev->mem_end   = mem->end;
+
+        /* obtain device IRQ number */
+        res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+        if (!res) {
+                dev_err(&pdev->dev, "cannot obtain IRQ\n");
+                ret = -ENXIO;
+                goto free;
+        }
+
+        netdev->irq = res->start;
+
+        /* setup driver-private data */
+        priv = netdev_priv(netdev);
+        priv->netdev = netdev;
+
+        priv->iobase = devm_ioremap_nocache(&pdev->dev, netdev->base_addr,
+                        mmio->end - mmio->start + 1);
+        if (!priv->iobase) {
+                dev_err(&pdev->dev, "cannot remap I/O memory space\n");
+                ret = -ENXIO;
+                goto error;
+        }
+
+        priv->membase = devm_ioremap_nocache(&pdev->dev, netdev->mem_start,
+                        mem->end - mem->start + 1);
+        if (!priv->membase) {
+                dev_err(&pdev->dev, "cannot remap memory space\n");
+                ret = -ENXIO;
+                goto error;
+        }
+
+        /* Allow the platform setup code to pass in a MAC address. */
+        if (pdev->dev.platform_data) {
+                struct ethoc_platform_data *pdata =
+                        (struct ethoc_platform_data *)pdev->dev.platform_data;
+                memcpy(netdev->dev_addr, pdata->hwaddr, IFHWADDRLEN);
+                priv->phy_id = pdata->phy_id;
+        }
+
+        /* Check that the given MAC address is valid. If it isn't, read the
+         * current MAC from the controller. */
+        if (!is_valid_ether_addr(netdev->dev_addr))
+                ethoc_get_mac_address(netdev, netdev->dev_addr);
+
+        /* Check the MAC again for validity, if it still isn't choose and
+         * program a random one. */
+        if (!is_valid_ether_addr(netdev->dev_addr))
+                random_ether_addr(netdev->dev_addr);
+
+        ethoc_set_mac_address(netdev, netdev->dev_addr);
+
+        /* register MII bus */
+        priv->mdio = mdiobus_alloc();
+        if (!priv->mdio) {
+                ret = -ENOMEM;
+                goto free;
+        }
+
+        priv->mdio->name = "ethoc-mdio";
+        snprintf(priv->mdio->id, MII_BUS_ID_SIZE, "%s-%d",
+                        priv->mdio->name, pdev->id);
+        priv->mdio->read = ethoc_mdio_read;
+        priv->mdio->write = ethoc_mdio_write;
+        priv->mdio->reset = ethoc_mdio_reset;
+        priv->mdio->priv = priv;
+
+        priv->mdio->irq = kmalloc(sizeof(int) * PHY_MAX_ADDR, GFP_KERNEL);
+        if (!priv->mdio->irq) {
+                ret = -ENOMEM;
+                goto free_mdio;
+        }
+
+        for (phy = 0; phy < PHY_MAX_ADDR; phy++)
+                priv->mdio->irq[phy] = PHY_POLL;
+
+        ret = mdiobus_register(priv->mdio);
+        if (ret) {
+                dev_err(&netdev->dev, "failed to register MDIO bus\n");
+                goto free_mdio;
+        }
+
+        ret = ethoc_mdio_probe(netdev);
+        if (ret) {
+                dev_err(&netdev->dev, "failed to probe MDIO bus\n");
+                goto error;
+        }
+
+        ether_setup(netdev);
+
+        /* setup the net_device structure */
+        netdev->netdev_ops = &ethoc_netdev_ops;
+        netdev->watchdog_timeo = ETHOC_TIMEOUT;
+        netdev->features |= 0;
+
+        /* setup NAPI */
+        memset(&priv->napi, 0, sizeof(priv->napi));
+        netif_napi_add(netdev, &priv->napi, ethoc_poll, 64);
+
+        spin_lock_init(&priv->rx_lock);
+        spin_lock_init(&priv->lock);
+
+        ret = register_netdev(netdev);
+        if (ret < 0) {
+                dev_err(&netdev->dev, "failed to register interface\n");
+                goto error;
+        }
+
+        goto out;
+
+error:
+        mdiobus_unregister(priv->mdio);
+free_mdio:
+        kfree(priv->mdio->irq);
+        mdiobus_free(priv->mdio);
+free:
+        free_netdev(netdev);
+out:
+        return ret;
+}
+
+/**
+ * ethoc_remove() - shutdown OpenCores ethernet MAC
+ * @pdev:       platform device
+ */
+static int ethoc_remove(struct platform_device *pdev)
+{
+        struct net_device *netdev = platform_get_drvdata(pdev);
+        struct ethoc *priv = netdev_priv(netdev);
+
+        platform_set_drvdata(pdev, NULL);
+
+        if (netdev) {
+                phy_disconnect(priv->phy);
+                priv->phy = NULL;
+
+                if (priv->mdio) {
+                        mdiobus_unregister(priv->mdio);
+                        kfree(priv->mdio->irq);
+                        mdiobus_free(priv->mdio);
+                }
+
+                unregister_netdev(netdev);
+                free_netdev(netdev);
+        }
+
+        return 0;
+}
+
+#ifdef CONFIG_PM
+static int ethoc_suspend(struct platform_device *pdev, pm_message_t state)
+{
+        return -ENOSYS;
+}
+
+static int ethoc_resume(struct platform_device *pdev)
+{
+        return -ENOSYS;
+}
+#else
+# define ethoc_suspend NULL
+# define ethoc_resume  NULL
+#endif
+
+static struct platform_driver ethoc_driver = {
+        .probe   = ethoc_probe,
+        .remove  = ethoc_remove,
+        .suspend = ethoc_suspend,
+        .resume  = ethoc_resume,
+        .driver  = {
+                .name = "ethoc",
+        },
+};
+
+static int __init ethoc_init(void)
+{
+        return platform_driver_register(&ethoc_driver);
+}
+
+static void __exit ethoc_exit(void)
+{
+        platform_driver_unregister(&ethoc_driver);
+}
+
+module_init(ethoc_init);
+module_exit(ethoc_exit);
+
+MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
+MODULE_DESCRIPTION("OpenCores Ethernet MAC driver");
+MODULE_LICENSE("GPL v2");
+