treewide: remove redundant IS_ERR() before error code check

[linux/fpc-iii.git] / drivers / net / ethernet / amd / au1000_eth.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 *
 * Alchemy Au1x00 ethernet driver
 *
 * Copyright 2001-2003, 2006 MontaVista Software Inc.
 * Copyright 2002 TimeSys Corp.
 * Added ethtool/mii-tool support,
 * Copyright 2004 Matt Porter <mporter@kernel.crashing.org>
 * Update: 2004 Bjoern Riemer, riemer@fokus.fraunhofer.de
 * or riemer@riemer-nt.de: fixed the link beat detection with
 * ioctls (SIOCGMIIPHY)
 * Copyright 2006 Herbert Valerio Riedel <hvr@gnu.org>
 *  converted to use linux-2.6.x's PHY framework
 *
 * Author: MontaVista Software, Inc.
 *              ppopov@mvista.com or source@mvista.com
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/capability.h>
#include <linux/dma-mapping.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/errno.h>
#include <linux/in.h>
#include <linux/ioport.h>
#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/mii.h>
#include <linux/skbuff.h>
#include <linux/delay.h>
#include <linux/crc32.h>
#include <linux/phy.h>
#include <linux/platform_device.h>
#include <linux/cpu.h>
#include <linux/io.h>

#include <asm/mipsregs.h>
#include <asm/irq.h>
#include <asm/processor.h>

#include <au1000.h>
#include <au1xxx_eth.h>
#include <prom.h>

#include "au1000_eth.h"

#ifdef AU1000_ETH_DEBUG
static int au1000_debug = 5;
#else
static int au1000_debug = 3;
#endif

#define AU1000_DEF_MSG_ENABLE   (NETIF_MSG_DRV  | \
                                NETIF_MSG_PROBE | \
                                NETIF_MSG_LINK)

#define DRV_NAME        "au1000_eth"
#define DRV_VERSION     "1.7"
#define DRV_AUTHOR      "Pete Popov <ppopov@embeddedalley.com>"
#define DRV_DESC        "Au1xxx on-chip Ethernet driver"

MODULE_AUTHOR(DRV_AUTHOR);
MODULE_DESCRIPTION(DRV_DESC);
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);

/* AU1000 MAC registers and bits */
#define MAC_CONTROL             0x0
#  define MAC_RX_ENABLE         (1 << 2)
#  define MAC_TX_ENABLE         (1 << 3)
#  define MAC_DEF_CHECK         (1 << 5)
#  define MAC_SET_BL(X)         (((X) & 0x3) << 6)
#  define MAC_AUTO_PAD          (1 << 8)
#  define MAC_DISABLE_RETRY     (1 << 10)
#  define MAC_DISABLE_BCAST     (1 << 11)
#  define MAC_LATE_COL          (1 << 12)
#  define MAC_HASH_MODE         (1 << 13)
#  define MAC_HASH_ONLY         (1 << 15)
#  define MAC_PASS_ALL          (1 << 16)
#  define MAC_INVERSE_FILTER    (1 << 17)
#  define MAC_PROMISCUOUS       (1 << 18)
#  define MAC_PASS_ALL_MULTI    (1 << 19)
#  define MAC_FULL_DUPLEX       (1 << 20)
#  define MAC_NORMAL_MODE       0
#  define MAC_INT_LOOPBACK      (1 << 21)
#  define MAC_EXT_LOOPBACK      (1 << 22)
#  define MAC_DISABLE_RX_OWN    (1 << 23)
#  define MAC_BIG_ENDIAN        (1 << 30)
#  define MAC_RX_ALL            (1 << 31)
#define MAC_ADDRESS_HIGH        0x4
#define MAC_ADDRESS_LOW         0x8
#define MAC_MCAST_HIGH          0xC
#define MAC_MCAST_LOW           0x10
#define MAC_MII_CNTRL           0x14
#  define MAC_MII_BUSY          (1 << 0)
#  define MAC_MII_READ          0
#  define MAC_MII_WRITE         (1 << 1)
#  define MAC_SET_MII_SELECT_REG(X) (((X) & 0x1f) << 6)
#  define MAC_SET_MII_SELECT_PHY(X) (((X) & 0x1f) << 11)
#define MAC_MII_DATA            0x18
#define MAC_FLOW_CNTRL          0x1C
#  define MAC_FLOW_CNTRL_BUSY   (1 << 0)
#  define MAC_FLOW_CNTRL_ENABLE (1 << 1)
#  define MAC_PASS_CONTROL      (1 << 2)
#  define MAC_SET_PAUSE(X)      (((X) & 0xffff) << 16)
#define MAC_VLAN1_TAG           0x20
#define MAC_VLAN2_TAG           0x24

/* Ethernet Controller Enable */
#  define MAC_EN_CLOCK_ENABLE   (1 << 0)
#  define MAC_EN_RESET0         (1 << 1)
#  define MAC_EN_TOSS           (0 << 2)
#  define MAC_EN_CACHEABLE      (1 << 3)
#  define MAC_EN_RESET1         (1 << 4)
#  define MAC_EN_RESET2         (1 << 5)
#  define MAC_DMA_RESET         (1 << 6)

/* Ethernet Controller DMA Channels */
/* offsets from MAC_TX_RING_ADDR address */
#define MAC_TX_BUFF0_STATUS     0x0
#  define TX_FRAME_ABORTED      (1 << 0)
#  define TX_JAB_TIMEOUT        (1 << 1)
#  define TX_NO_CARRIER         (1 << 2)
#  define TX_LOSS_CARRIER       (1 << 3)
#  define TX_EXC_DEF            (1 << 4)
#  define TX_LATE_COLL_ABORT    (1 << 5)
#  define TX_EXC_COLL           (1 << 6)
#  define TX_UNDERRUN           (1 << 7)
#  define TX_DEFERRED           (1 << 8)
#  define TX_LATE_COLL          (1 << 9)
#  define TX_COLL_CNT_MASK      (0xF << 10)
#  define TX_PKT_RETRY          (1 << 31)
#define MAC_TX_BUFF0_ADDR       0x4
#  define TX_DMA_ENABLE         (1 << 0)
#  define TX_T_DONE             (1 << 1)
#  define TX_GET_DMA_BUFFER(X)  (((X) >> 2) & 0x3)
#define MAC_TX_BUFF0_LEN        0x8
#define MAC_TX_BUFF1_STATUS     0x10
#define MAC_TX_BUFF1_ADDR       0x14
#define MAC_TX_BUFF1_LEN        0x18
#define MAC_TX_BUFF2_STATUS     0x20
#define MAC_TX_BUFF2_ADDR       0x24
#define MAC_TX_BUFF2_LEN        0x28
#define MAC_TX_BUFF3_STATUS     0x30
#define MAC_TX_BUFF3_ADDR       0x34
#define MAC_TX_BUFF3_LEN        0x38

/* offsets from MAC_RX_RING_ADDR */
#define MAC_RX_BUFF0_STATUS     0x0
#  define RX_FRAME_LEN_MASK     0x3fff
#  define RX_WDOG_TIMER         (1 << 14)
#  define RX_RUNT               (1 << 15)
#  define RX_OVERLEN            (1 << 16)
#  define RX_COLL               (1 << 17)
#  define RX_ETHER              (1 << 18)
#  define RX_MII_ERROR          (1 << 19)
#  define RX_DRIBBLING          (1 << 20)
#  define RX_CRC_ERROR          (1 << 21)
#  define RX_VLAN1              (1 << 22)
#  define RX_VLAN2              (1 << 23)
#  define RX_LEN_ERROR          (1 << 24)
#  define RX_CNTRL_FRAME        (1 << 25)
#  define RX_U_CNTRL_FRAME      (1 << 26)
#  define RX_MCAST_FRAME        (1 << 27)
#  define RX_BCAST_FRAME        (1 << 28)
#  define RX_FILTER_FAIL        (1 << 29)
#  define RX_PACKET_FILTER      (1 << 30)
#  define RX_MISSED_FRAME       (1 << 31)

#  define RX_ERROR (RX_WDOG_TIMER | RX_RUNT | RX_OVERLEN |  \
                    RX_COLL | RX_MII_ERROR | RX_CRC_ERROR | \
                    RX_LEN_ERROR | RX_U_CNTRL_FRAME | RX_MISSED_FRAME)
#define MAC_RX_BUFF0_ADDR       0x4
#  define RX_DMA_ENABLE         (1 << 0)
#  define RX_T_DONE             (1 << 1)
#  define RX_GET_DMA_BUFFER(X)  (((X) >> 2) & 0x3)
#  define RX_SET_BUFF_ADDR(X)   ((X) & 0xffffffc0)
#define MAC_RX_BUFF1_STATUS     0x10
#define MAC_RX_BUFF1_ADDR       0x14
#define MAC_RX_BUFF2_STATUS     0x20
#define MAC_RX_BUFF2_ADDR       0x24
#define MAC_RX_BUFF3_STATUS     0x30
#define MAC_RX_BUFF3_ADDR       0x34

/*
 * Theory of operation
 *
 * The Au1000 MACs use a simple rx and tx descriptor ring scheme.
 * There are four receive and four transmit descriptors.  These
 * descriptors are not in memory; rather, they are just a set of
 * hardware registers.
 *
 * Since the Au1000 has a coherent data cache, the receive and
 * transmit buffers are allocated from the KSEG0 segment. The
 * hardware registers, however, are still mapped at KSEG1 to
 * make sure there's no out-of-order writes, and that all writes
 * complete immediately.
 */

/*
 * board-specific configurations
 *
 * PHY detection algorithm
 *
 * If phy_static_config is undefined, the PHY setup is
 * autodetected:
 *
 * mii_probe() first searches the current MAC's MII bus for a PHY,
 * selecting the first (or last, if phy_search_highest_addr is
 * defined) PHY address not already claimed by another netdev.
 *
 * If nothing was found that way when searching for the 2nd ethernet
 * controller's PHY and phy1_search_mac0 is defined, then
 * the first MII bus is searched as well for an unclaimed PHY; this is
 * needed in case of a dual-PHY accessible only through the MAC0's MII
 * bus.
 *
 * Finally, if no PHY is found, then the corresponding ethernet
 * controller is not registered to the network subsystem.
 */

/* autodetection defaults: phy1_search_mac0 */

/* static PHY setup
 *
 * most boards PHY setup should be detectable properly with the
 * autodetection algorithm in mii_probe(), but in some cases (e.g. if
 * you have a switch attached, or want to use the PHY's interrupt
 * notification capabilities) you can provide a static PHY
 * configuration here
 *
 * IRQs may only be set, if a PHY address was configured
 * If a PHY address is given, also a bus id is required to be set
 *
 * ps: make sure the used irqs are configured properly in the board
 * specific irq-map
 */

static void au1000_enable_mac(struct net_device *dev, int force_reset)
{
        unsigned long flags;
        struct au1000_private *aup = netdev_priv(dev);

        spin_lock_irqsave(&aup->lock, flags);

        if (force_reset || (!aup->mac_enabled)) {
                writel(MAC_EN_CLOCK_ENABLE, aup->enable);
                wmb(); /* drain writebuffer */
                mdelay(2);
                writel((MAC_EN_RESET0 | MAC_EN_RESET1 | MAC_EN_RESET2
                                | MAC_EN_CLOCK_ENABLE), aup->enable);
                wmb(); /* drain writebuffer */
                mdelay(2);

                aup->mac_enabled = 1;
        }

        spin_unlock_irqrestore(&aup->lock, flags);
}

/*
 * MII operations
 */
static int au1000_mdio_read(struct net_device *dev, int phy_addr, int reg)
{
        struct au1000_private *aup = netdev_priv(dev);
        u32 *const mii_control_reg = &aup->mac->mii_control;
        u32 *const mii_data_reg = &aup->mac->mii_data;
        u32 timedout = 20;
        u32 mii_control;

        while (readl(mii_control_reg) & MAC_MII_BUSY) {
                mdelay(1);
                if (--timedout == 0) {
                        netdev_err(dev, "read_MII busy timeout!!\n");
                        return -1;
                }
        }

        mii_control = MAC_SET_MII_SELECT_REG(reg) |
                MAC_SET_MII_SELECT_PHY(phy_addr) | MAC_MII_READ;

        writel(mii_control, mii_control_reg);

        timedout = 20;
        while (readl(mii_control_reg) & MAC_MII_BUSY) {
                mdelay(1);
                if (--timedout == 0) {
                        netdev_err(dev, "mdio_read busy timeout!!\n");
                        return -1;
                }
        }
        return readl(mii_data_reg);
}

static void au1000_mdio_write(struct net_device *dev, int phy_addr,
                              int reg, u16 value)
{
        struct au1000_private *aup = netdev_priv(dev);
        u32 *const mii_control_reg = &aup->mac->mii_control;
        u32 *const mii_data_reg = &aup->mac->mii_data;
        u32 timedout = 20;
        u32 mii_control;

        while (readl(mii_control_reg) & MAC_MII_BUSY) {
                mdelay(1);
                if (--timedout == 0) {
                        netdev_err(dev, "mdio_write busy timeout!!\n");
                        return;
                }
        }

        mii_control = MAC_SET_MII_SELECT_REG(reg) |
                MAC_SET_MII_SELECT_PHY(phy_addr) | MAC_MII_WRITE;

        writel(value, mii_data_reg);
        writel(mii_control, mii_control_reg);
}

static int au1000_mdiobus_read(struct mii_bus *bus, int phy_addr, int regnum)
{
        struct net_device *const dev = bus->priv;

        /* make sure the MAC associated with this
         * mii_bus is enabled
         */
        au1000_enable_mac(dev, 0);

        return au1000_mdio_read(dev, phy_addr, regnum);
}

static int au1000_mdiobus_write(struct mii_bus *bus, int phy_addr, int regnum,
                                u16 value)
{
        struct net_device *const dev = bus->priv;

        /* make sure the MAC associated with this
         * mii_bus is enabled
         */
        au1000_enable_mac(dev, 0);

        au1000_mdio_write(dev, phy_addr, regnum, value);
        return 0;
}

static int au1000_mdiobus_reset(struct mii_bus *bus)
{
        struct net_device *const dev = bus->priv;

        /* make sure the MAC associated with this
         * mii_bus is enabled
         */
        au1000_enable_mac(dev, 0);

        return 0;
}

static void au1000_hard_stop(struct net_device *dev)
{
        struct au1000_private *aup = netdev_priv(dev);
        u32 reg;

        netif_dbg(aup, drv, dev, "hard stop\n");

        reg = readl(&aup->mac->control);
        reg &= ~(MAC_RX_ENABLE | MAC_TX_ENABLE);
        writel(reg, &aup->mac->control);
        wmb(); /* drain writebuffer */
        mdelay(10);
}

static void au1000_enable_rx_tx(struct net_device *dev)
{
        struct au1000_private *aup = netdev_priv(dev);
        u32 reg;

        netif_dbg(aup, hw, dev, "enable_rx_tx\n");

        reg = readl(&aup->mac->control);
        reg |= (MAC_RX_ENABLE | MAC_TX_ENABLE);
        writel(reg, &aup->mac->control);
        wmb(); /* drain writebuffer */
        mdelay(10);
}

static void
au1000_adjust_link(struct net_device *dev)
{
        struct au1000_private *aup = netdev_priv(dev);
        struct phy_device *phydev = dev->phydev;
        unsigned long flags;
        u32 reg;

        int status_change = 0;

        BUG_ON(!phydev);

        spin_lock_irqsave(&aup->lock, flags);

        if (phydev->link && (aup->old_speed != phydev->speed)) {
                /* speed changed */

                switch (phydev->speed) {
                case SPEED_10:
                case SPEED_100:
                        break;
                default:
                        netdev_warn(dev, "Speed (%d) is not 10/100 ???\n",
                                                        phydev->speed);
                        break;
                }

                aup->old_speed = phydev->speed;

                status_change = 1;
        }

        if (phydev->link && (aup->old_duplex != phydev->duplex)) {
                /* duplex mode changed */

                /* switching duplex mode requires to disable rx and tx! */
                au1000_hard_stop(dev);

                reg = readl(&aup->mac->control);
                if (DUPLEX_FULL == phydev->duplex) {
                        reg |= MAC_FULL_DUPLEX;
                        reg &= ~MAC_DISABLE_RX_OWN;
                } else {
                        reg &= ~MAC_FULL_DUPLEX;
                        reg |= MAC_DISABLE_RX_OWN;
                }
                writel(reg, &aup->mac->control);
                wmb(); /* drain writebuffer */
                mdelay(1);

                au1000_enable_rx_tx(dev);
                aup->old_duplex = phydev->duplex;

                status_change = 1;
        }

        if (phydev->link != aup->old_link) {
                /* link state changed */

                if (!phydev->link) {
                        /* link went down */
                        aup->old_speed = 0;
                        aup->old_duplex = -1;
                }

                aup->old_link = phydev->link;
                status_change = 1;
        }

        spin_unlock_irqrestore(&aup->lock, flags);

        if (status_change) {
                if (phydev->link)
                        netdev_info(dev, "link up (%d/%s)\n",
                               phydev->speed,
                               DUPLEX_FULL == phydev->duplex ? "Full" : "Half");
                else
                        netdev_info(dev, "link down\n");
        }
}

static int au1000_mii_probe(struct net_device *dev)
{
        struct au1000_private *const aup = netdev_priv(dev);
        struct phy_device *phydev = NULL;
        int phy_addr;

        if (aup->phy_static_config) {
                BUG_ON(aup->mac_id < 0 || aup->mac_id > 1);

                if (aup->phy_addr)
                        phydev = mdiobus_get_phy(aup->mii_bus, aup->phy_addr);
                else
                        netdev_info(dev, "using PHY-less setup\n");
                return 0;
        }

        /* find the first (lowest address) PHY
         * on the current MAC's MII bus
         */
        for (phy_addr = 0; phy_addr < PHY_MAX_ADDR; phy_addr++)
                if (mdiobus_get_phy(aup->mii_bus, phy_addr)) {
                        phydev = mdiobus_get_phy(aup->mii_bus, phy_addr);
                        if (!aup->phy_search_highest_addr)
                                /* break out with first one found */
                                break;
                }

        if (aup->phy1_search_mac0) {
                /* try harder to find a PHY */
                if (!phydev && (aup->mac_id == 1)) {
                        /* no PHY found, maybe we have a dual PHY? */
                        dev_info(&dev->dev, ": no PHY found on MAC1, "
                                "let's see if it's attached to MAC0...\n");

                        /* find the first (lowest address) non-attached
                         * PHY on the MAC0 MII bus
                         */
                        for (phy_addr = 0; phy_addr < PHY_MAX_ADDR; phy_addr++) {
                                struct phy_device *const tmp_phydev =
                                        mdiobus_get_phy(aup->mii_bus,
                                                        phy_addr);

                                if (aup->mac_id == 1)
                                        break;

                                /* no PHY here... */
                                if (!tmp_phydev)
                                        continue;

                                /* already claimed by MAC0 */
                                if (tmp_phydev->attached_dev)
                                        continue;

                                phydev = tmp_phydev;
                                break; /* found it */
                        }
                }
        }

        if (!phydev) {
                netdev_err(dev, "no PHY found\n");
                return -1;
        }

        /* now we are supposed to have a proper phydev, to attach to... */
        BUG_ON(phydev->attached_dev);

        phydev = phy_connect(dev, phydev_name(phydev),
                             &au1000_adjust_link, PHY_INTERFACE_MODE_MII);

        if (IS_ERR(phydev)) {
                netdev_err(dev, "Could not attach to PHY\n");
                return PTR_ERR(phydev);
        }

        phy_set_max_speed(phydev, SPEED_100);

        aup->old_link = 0;
        aup->old_speed = 0;
        aup->old_duplex = -1;

        phy_attached_info(phydev);

        return 0;
}


/*
 * Buffer allocation/deallocation routines. The buffer descriptor returned
 * has the virtual and dma address of a buffer suitable for
 * both, receive and transmit operations.
 */
static struct db_dest *au1000_GetFreeDB(struct au1000_private *aup)
{
        struct db_dest *pDB;
        pDB = aup->pDBfree;

        if (pDB)
                aup->pDBfree = pDB->pnext;

        return pDB;
}

void au1000_ReleaseDB(struct au1000_private *aup, struct db_dest *pDB)
{
        struct db_dest *pDBfree = aup->pDBfree;
        if (pDBfree)
                pDBfree->pnext = pDB;
        aup->pDBfree = pDB;
}

static void au1000_reset_mac_unlocked(struct net_device *dev)
{
        struct au1000_private *const aup = netdev_priv(dev);
        int i;

        au1000_hard_stop(dev);

        writel(MAC_EN_CLOCK_ENABLE, aup->enable);
        wmb(); /* drain writebuffer */
        mdelay(2);
        writel(0, aup->enable);
        wmb(); /* drain writebuffer */
        mdelay(2);

        aup->tx_full = 0;
        for (i = 0; i < NUM_RX_DMA; i++) {
                /* reset control bits */
                aup->rx_dma_ring[i]->buff_stat &= ~0xf;
        }
        for (i = 0; i < NUM_TX_DMA; i++) {
                /* reset control bits */
                aup->tx_dma_ring[i]->buff_stat &= ~0xf;
        }

        aup->mac_enabled = 0;

}

static void au1000_reset_mac(struct net_device *dev)
{
        struct au1000_private *const aup = netdev_priv(dev);
        unsigned long flags;

        netif_dbg(aup, hw, dev, "reset mac, aup %x\n",
                                        (unsigned)aup);

        spin_lock_irqsave(&aup->lock, flags);

        au1000_reset_mac_unlocked(dev);

        spin_unlock_irqrestore(&aup->lock, flags);
}

/*
 * Setup the receive and transmit "rings".  These pointers are the addresses
 * of the rx and tx MAC DMA registers so they are fixed by the hardware --
 * these are not descriptors sitting in memory.
 */
static void
au1000_setup_hw_rings(struct au1000_private *aup, void __iomem *tx_base)
{
        int i;

        for (i = 0; i < NUM_RX_DMA; i++) {
                aup->rx_dma_ring[i] = (struct rx_dma *)
                        (tx_base + 0x100 + sizeof(struct rx_dma) * i);
        }
        for (i = 0; i < NUM_TX_DMA; i++) {
                aup->tx_dma_ring[i] = (struct tx_dma *)
                        (tx_base + sizeof(struct tx_dma) * i);
        }
}

/*
 * ethtool operations
 */

static void
au1000_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
{
        struct au1000_private *aup = netdev_priv(dev);

        strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
        strlcpy(info->version, DRV_VERSION, sizeof(info->version));
        snprintf(info->bus_info, sizeof(info->bus_info), "%s %d", DRV_NAME,
                 aup->mac_id);
}

static void au1000_set_msglevel(struct net_device *dev, u32 value)
{
        struct au1000_private *aup = netdev_priv(dev);
        aup->msg_enable = value;
}

static u32 au1000_get_msglevel(struct net_device *dev)
{
        struct au1000_private *aup = netdev_priv(dev);
        return aup->msg_enable;
}

static const struct ethtool_ops au1000_ethtool_ops = {
        .get_drvinfo = au1000_get_drvinfo,
        .get_link = ethtool_op_get_link,
        .get_msglevel = au1000_get_msglevel,
        .set_msglevel = au1000_set_msglevel,
        .get_link_ksettings = phy_ethtool_get_link_ksettings,
        .set_link_ksettings = phy_ethtool_set_link_ksettings,
};


/*
 * Initialize the interface.
 *
 * When the device powers up, the clocks are disabled and the
 * mac is in reset state.  When the interface is closed, we
 * do the same -- reset the device and disable the clocks to
 * conserve power. Thus, whenever au1000_init() is called,
 * the device should already be in reset state.
 */
static int au1000_init(struct net_device *dev)
{
        struct au1000_private *aup = netdev_priv(dev);
        unsigned long flags;
        int i;
        u32 control;

        netif_dbg(aup, hw, dev, "au1000_init\n");

        /* bring the device out of reset */
        au1000_enable_mac(dev, 1);

        spin_lock_irqsave(&aup->lock, flags);

        writel(0, &aup->mac->control);
        aup->tx_head = (aup->tx_dma_ring[0]->buff_stat & 0xC) >> 2;
        aup->tx_tail = aup->tx_head;
        aup->rx_head = (aup->rx_dma_ring[0]->buff_stat & 0xC) >> 2;

        writel(dev->dev_addr[5]<<8 | dev->dev_addr[4],
                                        &aup->mac->mac_addr_high);
        writel(dev->dev_addr[3]<<24 | dev->dev_addr[2]<<16 |
                dev->dev_addr[1]<<8 | dev->dev_addr[0],
                                        &aup->mac->mac_addr_low);


        for (i = 0; i < NUM_RX_DMA; i++)
                aup->rx_dma_ring[i]->buff_stat |= RX_DMA_ENABLE;

        wmb(); /* drain writebuffer */

        control = MAC_RX_ENABLE | MAC_TX_ENABLE;
#ifndef CONFIG_CPU_LITTLE_ENDIAN
        control |= MAC_BIG_ENDIAN;
#endif
        if (dev->phydev) {
                if (dev->phydev->link && (DUPLEX_FULL == dev->phydev->duplex))
                        control |= MAC_FULL_DUPLEX;
                else
                        control |= MAC_DISABLE_RX_OWN;
        } else { /* PHY-less op, assume full-duplex */
                control |= MAC_FULL_DUPLEX;
        }

        writel(control, &aup->mac->control);
        writel(0x8100, &aup->mac->vlan1_tag); /* activate vlan support */
        wmb(); /* drain writebuffer */

        spin_unlock_irqrestore(&aup->lock, flags);
        return 0;
}

static inline void au1000_update_rx_stats(struct net_device *dev, u32 status)
{
        struct net_device_stats *ps = &dev->stats;

        ps->rx_packets++;
        if (status & RX_MCAST_FRAME)
                ps->multicast++;

        if (status & RX_ERROR) {
                ps->rx_errors++;
                if (status & RX_MISSED_FRAME)
                        ps->rx_missed_errors++;
                if (status & (RX_OVERLEN | RX_RUNT | RX_LEN_ERROR))
                        ps->rx_length_errors++;
                if (status & RX_CRC_ERROR)
                        ps->rx_crc_errors++;
                if (status & RX_COLL)
                        ps->collisions++;
        } else
                ps->rx_bytes += status & RX_FRAME_LEN_MASK;

}

/*
 * Au1000 receive routine.
 */
static int au1000_rx(struct net_device *dev)
{
        struct au1000_private *aup = netdev_priv(dev);
        struct sk_buff *skb;
        struct rx_dma *prxd;
        u32 buff_stat, status;
        struct db_dest *pDB;
        u32     frmlen;

        netif_dbg(aup, rx_status, dev, "au1000_rx head %d\n", aup->rx_head);

        prxd = aup->rx_dma_ring[aup->rx_head];
        buff_stat = prxd->buff_stat;
        while (buff_stat & RX_T_DONE)  {
                status = prxd->status;
                pDB = aup->rx_db_inuse[aup->rx_head];
                au1000_update_rx_stats(dev, status);
                if (!(status & RX_ERROR))  {

                        /* good frame */
                        frmlen = (status & RX_FRAME_LEN_MASK);
                        frmlen -= 4; /* Remove FCS */
                        skb = netdev_alloc_skb(dev, frmlen + 2);
                        if (skb == NULL) {
                                dev->stats.rx_dropped++;
                                continue;
                        }
                        skb_reserve(skb, 2);    /* 16 byte IP header align */
                        skb_copy_to_linear_data(skb,
                                (unsigned char *)pDB->vaddr, frmlen);
                        skb_put(skb, frmlen);
                        skb->protocol = eth_type_trans(skb, dev);
                        netif_rx(skb);  /* pass the packet to upper layers */
                } else {
                        if (au1000_debug > 4) {
                                pr_err("rx_error(s):");
                                if (status & RX_MISSED_FRAME)
                                        pr_cont(" miss");
                                if (status & RX_WDOG_TIMER)
                                        pr_cont(" wdog");
                                if (status & RX_RUNT)
                                        pr_cont(" runt");
                                if (status & RX_OVERLEN)
                                        pr_cont(" overlen");
                                if (status & RX_COLL)
                                        pr_cont(" coll");
                                if (status & RX_MII_ERROR)
                                        pr_cont(" mii error");
                                if (status & RX_CRC_ERROR)
                                        pr_cont(" crc error");
                                if (status & RX_LEN_ERROR)
                                        pr_cont(" len error");
                                if (status & RX_U_CNTRL_FRAME)
                                        pr_cont(" u control frame");
                                pr_cont("\n");
                        }
                }
                prxd->buff_stat = (u32)(pDB->dma_addr | RX_DMA_ENABLE);
                aup->rx_head = (aup->rx_head + 1) & (NUM_RX_DMA - 1);
                wmb(); /* drain writebuffer */

                /* next descriptor */
                prxd = aup->rx_dma_ring[aup->rx_head];
                buff_stat = prxd->buff_stat;
        }
        return 0;
}

static void au1000_update_tx_stats(struct net_device *dev, u32 status)
{
        struct net_device_stats *ps = &dev->stats;

        if (status & TX_FRAME_ABORTED) {
                if (!dev->phydev || (DUPLEX_FULL == dev->phydev->duplex)) {
                        if (status & (TX_JAB_TIMEOUT | TX_UNDERRUN)) {
                                /* any other tx errors are only valid
                                 * in half duplex mode
                                 */
                                ps->tx_errors++;
                                ps->tx_aborted_errors++;
                        }
                } else {
                        ps->tx_errors++;
                        ps->tx_aborted_errors++;
                        if (status & (TX_NO_CARRIER | TX_LOSS_CARRIER))
                                ps->tx_carrier_errors++;
                }
        }
}

/*
 * Called from the interrupt service routine to acknowledge
 * the TX DONE bits.  This is a must if the irq is setup as
 * edge triggered.
 */
static void au1000_tx_ack(struct net_device *dev)
{
        struct au1000_private *aup = netdev_priv(dev);
        struct tx_dma *ptxd;

        ptxd = aup->tx_dma_ring[aup->tx_tail];

        while (ptxd->buff_stat & TX_T_DONE) {
                au1000_update_tx_stats(dev, ptxd->status);
                ptxd->buff_stat &= ~TX_T_DONE;
                ptxd->len = 0;
                wmb(); /* drain writebuffer */

                aup->tx_tail = (aup->tx_tail + 1) & (NUM_TX_DMA - 1);
                ptxd = aup->tx_dma_ring[aup->tx_tail];

                if (aup->tx_full) {
                        aup->tx_full = 0;
                        netif_wake_queue(dev);
                }
        }
}

/*
 * Au1000 interrupt service routine.
 */
static irqreturn_t au1000_interrupt(int irq, void *dev_id)
{
        struct net_device *dev = dev_id;

        /* Handle RX interrupts first to minimize chance of overrun */

        au1000_rx(dev);
        au1000_tx_ack(dev);
        return IRQ_RETVAL(1);
}

static int au1000_open(struct net_device *dev)
{
        int retval;
        struct au1000_private *aup = netdev_priv(dev);

        netif_dbg(aup, drv, dev, "open: dev=%p\n", dev);

        retval = request_irq(dev->irq, au1000_interrupt, 0,
                                        dev->name, dev);
        if (retval) {
                netdev_err(dev, "unable to get IRQ %d\n", dev->irq);
                return retval;
        }

        retval = au1000_init(dev);
        if (retval) {
                netdev_err(dev, "error in au1000_init\n");
                free_irq(dev->irq, dev);
                return retval;
        }

        if (dev->phydev)
                phy_start(dev->phydev);

        netif_start_queue(dev);

        netif_dbg(aup, drv, dev, "open: Initialization done.\n");

        return 0;
}

static int au1000_close(struct net_device *dev)
{
        unsigned long flags;
        struct au1000_private *const aup = netdev_priv(dev);

        netif_dbg(aup, drv, dev, "close: dev=%p\n", dev);

        if (dev->phydev)
                phy_stop(dev->phydev);

        spin_lock_irqsave(&aup->lock, flags);

        au1000_reset_mac_unlocked(dev);

        /* stop the device */
        netif_stop_queue(dev);

        /* disable the interrupt */
        free_irq(dev->irq, dev);
        spin_unlock_irqrestore(&aup->lock, flags);

        return 0;
}

/*
 * Au1000 transmit routine.
 */
static netdev_tx_t au1000_tx(struct sk_buff *skb, struct net_device *dev)
{
        struct au1000_private *aup = netdev_priv(dev);
        struct net_device_stats *ps = &dev->stats;
        struct tx_dma *ptxd;
        u32 buff_stat;
        struct db_dest *pDB;
        int i;

        netif_dbg(aup, tx_queued, dev, "tx: aup %x len=%d, data=%p, head %d\n",
                                (unsigned)aup, skb->len,
                                skb->data, aup->tx_head);

        ptxd = aup->tx_dma_ring[aup->tx_head];
        buff_stat = ptxd->buff_stat;
        if (buff_stat & TX_DMA_ENABLE) {
                /* We've wrapped around and the transmitter is still busy */
                netif_stop_queue(dev);
                aup->tx_full = 1;
                return NETDEV_TX_BUSY;
        } else if (buff_stat & TX_T_DONE) {
                au1000_update_tx_stats(dev, ptxd->status);
                ptxd->len = 0;
        }

        if (aup->tx_full) {
                aup->tx_full = 0;
                netif_wake_queue(dev);
        }

        pDB = aup->tx_db_inuse[aup->tx_head];
        skb_copy_from_linear_data(skb, (void *)pDB->vaddr, skb->len);
        if (skb->len < ETH_ZLEN) {
                for (i = skb->len; i < ETH_ZLEN; i++)
                        ((char *)pDB->vaddr)[i] = 0;

                ptxd->len = ETH_ZLEN;
        } else
                ptxd->len = skb->len;

        ps->tx_packets++;
        ps->tx_bytes += ptxd->len;

        ptxd->buff_stat = pDB->dma_addr | TX_DMA_ENABLE;
        wmb(); /* drain writebuffer */
        dev_kfree_skb(skb);
        aup->tx_head = (aup->tx_head + 1) & (NUM_TX_DMA - 1);
        return NETDEV_TX_OK;
}

/*
 * The Tx ring has been full longer than the watchdog timeout
 * value. The transmitter must be hung?
 */
static void au1000_tx_timeout(struct net_device *dev, unsigned int txqueue)
{
        netdev_err(dev, "au1000_tx_timeout: dev=%p\n", dev);
        au1000_reset_mac(dev);
        au1000_init(dev);
        netif_trans_update(dev); /* prevent tx timeout */
        netif_wake_queue(dev);
}

static void au1000_multicast_list(struct net_device *dev)
{
        struct au1000_private *aup = netdev_priv(dev);
        u32 reg;

        netif_dbg(aup, drv, dev, "%s: flags=%x\n", __func__, dev->flags);
        reg = readl(&aup->mac->control);
        if (dev->flags & IFF_PROMISC) {                 /* Set promiscuous. */
                reg |= MAC_PROMISCUOUS;
        } else if ((dev->flags & IFF_ALLMULTI)  ||
                           netdev_mc_count(dev) > MULTICAST_FILTER_LIMIT) {
                reg |= MAC_PASS_ALL_MULTI;
                reg &= ~MAC_PROMISCUOUS;
                netdev_info(dev, "Pass all multicast\n");
        } else {
                struct netdev_hw_addr *ha;
                u32 mc_filter[2];       /* Multicast hash filter */

                mc_filter[1] = mc_filter[0] = 0;
                netdev_for_each_mc_addr(ha, dev)
                        set_bit(ether_crc(ETH_ALEN, ha->addr)>>26,
                                        (long *)mc_filter);
                writel(mc_filter[1], &aup->mac->multi_hash_high);
                writel(mc_filter[0], &aup->mac->multi_hash_low);
                reg &= ~MAC_PROMISCUOUS;
                reg |= MAC_HASH_MODE;
        }
        writel(reg, &aup->mac->control);
}

static const struct net_device_ops au1000_netdev_ops = {
        .ndo_open               = au1000_open,
        .ndo_stop               = au1000_close,
        .ndo_start_xmit         = au1000_tx,
        .ndo_set_rx_mode        = au1000_multicast_list,
        .ndo_do_ioctl           = phy_do_ioctl_running,
        .ndo_tx_timeout         = au1000_tx_timeout,
        .ndo_set_mac_address    = eth_mac_addr,
        .ndo_validate_addr      = eth_validate_addr,
};

static int au1000_probe(struct platform_device *pdev)
{
        struct au1000_private *aup = NULL;
        struct au1000_eth_platform_data *pd;
        struct net_device *dev = NULL;
        struct db_dest *pDB, *pDBfree;
        int irq, i, err = 0;
        struct resource *base, *macen, *macdma;

        base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!base) {
                dev_err(&pdev->dev, "failed to retrieve base register\n");
                err = -ENODEV;
                goto out;
        }

        macen = platform_get_resource(pdev, IORESOURCE_MEM, 1);
        if (!macen) {
                dev_err(&pdev->dev, "failed to retrieve MAC Enable register\n");
                err = -ENODEV;
                goto out;
        }

        irq = platform_get_irq(pdev, 0);
        if (irq < 0) {
                err = -ENODEV;
                goto out;
        }

        macdma = platform_get_resource(pdev, IORESOURCE_MEM, 2);
        if (!macdma) {
                dev_err(&pdev->dev, "failed to retrieve MACDMA registers\n");
                err = -ENODEV;
                goto out;
        }

        if (!request_mem_region(base->start, resource_size(base),
                                                        pdev->name)) {
                dev_err(&pdev->dev, "failed to request memory region for base registers\n");
                err = -ENXIO;
                goto out;
        }

        if (!request_mem_region(macen->start, resource_size(macen),
                                                        pdev->name)) {
                dev_err(&pdev->dev, "failed to request memory region for MAC enable register\n");
                err = -ENXIO;
                goto err_request;
        }

        if (!request_mem_region(macdma->start, resource_size(macdma),
                                                        pdev->name)) {
                dev_err(&pdev->dev, "failed to request MACDMA memory region\n");
                err = -ENXIO;
                goto err_macdma;
        }

        dev = alloc_etherdev(sizeof(struct au1000_private));
        if (!dev) {
                err = -ENOMEM;
                goto err_alloc;
        }

        SET_NETDEV_DEV(dev, &pdev->dev);
        platform_set_drvdata(pdev, dev);
        aup = netdev_priv(dev);

        spin_lock_init(&aup->lock);
        aup->msg_enable = (au1000_debug < 4 ?
                                AU1000_DEF_MSG_ENABLE : au1000_debug);

        /* Allocate the data buffers
         * Snooping works fine with eth on all au1xxx
         */
        aup->vaddr = (u32)dma_alloc_attrs(&pdev->dev, MAX_BUF_SIZE *
                                          (NUM_TX_BUFFS + NUM_RX_BUFFS),
                                          &aup->dma_addr, 0,
                                          DMA_ATTR_NON_CONSISTENT);
        if (!aup->vaddr) {
                dev_err(&pdev->dev, "failed to allocate data buffers\n");
                err = -ENOMEM;
                goto err_vaddr;
        }

        /* aup->mac is the base address of the MAC's registers */
        aup->mac = (struct mac_reg *)
                        ioremap(base->start, resource_size(base));
        if (!aup->mac) {
                dev_err(&pdev->dev, "failed to ioremap MAC registers\n");
                err = -ENXIO;
                goto err_remap1;
        }

        /* Setup some variables for quick register address access */
        aup->enable = (u32 *)ioremap(macen->start,
                                                resource_size(macen));
        if (!aup->enable) {
                dev_err(&pdev->dev, "failed to ioremap MAC enable register\n");
                err = -ENXIO;
                goto err_remap2;
        }
        aup->mac_id = pdev->id;

        aup->macdma = ioremap(macdma->start, resource_size(macdma));
        if (!aup->macdma) {
                dev_err(&pdev->dev, "failed to ioremap MACDMA registers\n");
                err = -ENXIO;
                goto err_remap3;
        }

        au1000_setup_hw_rings(aup, aup->macdma);

        writel(0, aup->enable);
        aup->mac_enabled = 0;

        pd = dev_get_platdata(&pdev->dev);
        if (!pd) {
                dev_info(&pdev->dev, "no platform_data passed,"
                                        " PHY search on MAC0\n");
                aup->phy1_search_mac0 = 1;
        } else {
                if (is_valid_ether_addr(pd->mac)) {
                        memcpy(dev->dev_addr, pd->mac, ETH_ALEN);
                } else {
                        /* Set a random MAC since no valid provided by platform_data. */
                        eth_hw_addr_random(dev);
                }

                aup->phy_static_config = pd->phy_static_config;
                aup->phy_search_highest_addr = pd->phy_search_highest_addr;
                aup->phy1_search_mac0 = pd->phy1_search_mac0;
                aup->phy_addr = pd->phy_addr;
                aup->phy_busid = pd->phy_busid;
                aup->phy_irq = pd->phy_irq;
        }

        if (aup->phy_busid > 0) {
                dev_err(&pdev->dev, "MAC0-associated PHY attached 2nd MACs MII bus not supported yet\n");
                err = -ENODEV;
                goto err_mdiobus_alloc;
        }

        aup->mii_bus = mdiobus_alloc();
        if (aup->mii_bus == NULL) {
                dev_err(&pdev->dev, "failed to allocate mdiobus structure\n");
                err = -ENOMEM;
                goto err_mdiobus_alloc;
        }

        aup->mii_bus->priv = dev;
        aup->mii_bus->read = au1000_mdiobus_read;
        aup->mii_bus->write = au1000_mdiobus_write;
        aup->mii_bus->reset = au1000_mdiobus_reset;
        aup->mii_bus->name = "au1000_eth_mii";
        snprintf(aup->mii_bus->id, MII_BUS_ID_SIZE, "%s-%x",
                pdev->name, aup->mac_id);

        /* if known, set corresponding PHY IRQs */
        if (aup->phy_static_config)
                if (aup->phy_irq && aup->phy_busid == aup->mac_id)
                        aup->mii_bus->irq[aup->phy_addr] = aup->phy_irq;

        err = mdiobus_register(aup->mii_bus);
        if (err) {
                dev_err(&pdev->dev, "failed to register MDIO bus\n");
                goto err_mdiobus_reg;
        }

        err = au1000_mii_probe(dev);
        if (err != 0)
                goto err_out;

        pDBfree = NULL;
        /* setup the data buffer descriptors and attach a buffer to each one */
        pDB = aup->db;
        for (i = 0; i < (NUM_TX_BUFFS+NUM_RX_BUFFS); i++) {
                pDB->pnext = pDBfree;
                pDBfree = pDB;
                pDB->vaddr = (u32 *)((unsigned)aup->vaddr + MAX_BUF_SIZE*i);
                pDB->dma_addr = (dma_addr_t)virt_to_bus(pDB->vaddr);
                pDB++;
        }
        aup->pDBfree = pDBfree;

        err = -ENODEV;
        for (i = 0; i < NUM_RX_DMA; i++) {
                pDB = au1000_GetFreeDB(aup);
                if (!pDB)
                        goto err_out;

                aup->rx_dma_ring[i]->buff_stat = (unsigned)pDB->dma_addr;
                aup->rx_db_inuse[i] = pDB;
        }

        err = -ENODEV;
        for (i = 0; i < NUM_TX_DMA; i++) {
                pDB = au1000_GetFreeDB(aup);
                if (!pDB)
                        goto err_out;

                aup->tx_dma_ring[i]->buff_stat = (unsigned)pDB->dma_addr;
                aup->tx_dma_ring[i]->len = 0;
                aup->tx_db_inuse[i] = pDB;
        }

        dev->base_addr = base->start;
        dev->irq = irq;
        dev->netdev_ops = &au1000_netdev_ops;
        dev->ethtool_ops = &au1000_ethtool_ops;
        dev->watchdog_timeo = ETH_TX_TIMEOUT;

        /*
         * The boot code uses the ethernet controller, so reset it to start
         * fresh.  au1000_init() expects that the device is in reset state.
         */
        au1000_reset_mac(dev);

        err = register_netdev(dev);
        if (err) {
                netdev_err(dev, "Cannot register net device, aborting.\n");
                goto err_out;
        }

        netdev_info(dev, "Au1xx0 Ethernet found at 0x%lx, irq %d\n",
                        (unsigned long)base->start, irq);

        pr_info_once("%s version %s %s\n", DRV_NAME, DRV_VERSION, DRV_AUTHOR);

        return 0;

err_out:
        if (aup->mii_bus != NULL)
                mdiobus_unregister(aup->mii_bus);

        /* here we should have a valid dev plus aup-> register addresses
         * so we can reset the mac properly.
         */
        au1000_reset_mac(dev);

        for (i = 0; i < NUM_RX_DMA; i++) {
                if (aup->rx_db_inuse[i])
                        au1000_ReleaseDB(aup, aup->rx_db_inuse[i]);
        }
        for (i = 0; i < NUM_TX_DMA; i++) {
                if (aup->tx_db_inuse[i])
                        au1000_ReleaseDB(aup, aup->tx_db_inuse[i]);
        }
err_mdiobus_reg:
        mdiobus_free(aup->mii_bus);
err_mdiobus_alloc:
        iounmap(aup->macdma);
err_remap3:
        iounmap(aup->enable);
err_remap2:
        iounmap(aup->mac);
err_remap1:
        dma_free_attrs(&pdev->dev, MAX_BUF_SIZE * (NUM_TX_BUFFS + NUM_RX_BUFFS),
                        (void *)aup->vaddr, aup->dma_addr,
                        DMA_ATTR_NON_CONSISTENT);
err_vaddr:
        free_netdev(dev);
err_alloc:
        release_mem_region(macdma->start, resource_size(macdma));
err_macdma:
        release_mem_region(macen->start, resource_size(macen));
err_request:
        release_mem_region(base->start, resource_size(base));
out:
        return err;
}

static int au1000_remove(struct platform_device *pdev)
{
        struct net_device *dev = platform_get_drvdata(pdev);
        struct au1000_private *aup = netdev_priv(dev);
        int i;
        struct resource *base, *macen;

        unregister_netdev(dev);
        mdiobus_unregister(aup->mii_bus);
        mdiobus_free(aup->mii_bus);

        for (i = 0; i < NUM_RX_DMA; i++)
                if (aup->rx_db_inuse[i])
                        au1000_ReleaseDB(aup, aup->rx_db_inuse[i]);

        for (i = 0; i < NUM_TX_DMA; i++)
                if (aup->tx_db_inuse[i])
                        au1000_ReleaseDB(aup, aup->tx_db_inuse[i]);

        dma_free_attrs(&pdev->dev, MAX_BUF_SIZE * (NUM_TX_BUFFS + NUM_RX_BUFFS),
                        (void *)aup->vaddr, aup->dma_addr,
                        DMA_ATTR_NON_CONSISTENT);

        iounmap(aup->macdma);
        iounmap(aup->mac);
        iounmap(aup->enable);

        base = platform_get_resource(pdev, IORESOURCE_MEM, 2);
        release_mem_region(base->start, resource_size(base));

        base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        release_mem_region(base->start, resource_size(base));

        macen = platform_get_resource(pdev, IORESOURCE_MEM, 1);
        release_mem_region(macen->start, resource_size(macen));

        free_netdev(dev);

        return 0;
}

static struct platform_driver au1000_eth_driver = {
        .probe  = au1000_probe,
        .remove = au1000_remove,
        .driver = {
                .name   = "au1000-eth",
        },
};

module_platform_driver(au1000_eth_driver);

MODULE_ALIAS("platform:au1000-eth");