/*
 * Xilinx Axi Ethernet device driver
 *
 * Copyright (c) 2008 Nissin Systems Co., Ltd.,  Yoshio Kashiwagi
 * Copyright (c) 2005-2008 DLA Systems,  David H. Lynch Jr. <dhlii@dlasys.net>
 * Copyright (c) 2008-2009 Secret Lab Technologies Ltd.
 * Copyright (c) 2010 - 2011 Michal Simek <monstr@monstr.eu>
 * Copyright (c) 2010 - 2011 PetaLogix
 * Copyright (c) 2010 - 2012 Xilinx, Inc. All rights reserved.
 *
 * This is a driver for the Xilinx Axi Ethernet which is used in the Virtex6
 * and Spartan6.
 *
 * TODO:
 *  - Add Axi Fifo support.
 *  - Factor out Axi DMA code into separate driver.
 *  - Test and fix basic multicast filtering.
 *  - Add support for extended multicast filtering.
 *  - Test basic VLAN support.
 *  - Add support for extended VLAN support.
 */

#include <linux/delay.h>
#include <linux/etherdevice.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/of_mdio.h>
#include <linux/of_net.h>
#include <linux/of_platform.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/phy.h>
#include <linux/mii.h>
#include <linux/ethtool.h>

#include "xilinx_axienet.h"

/* Descriptors defines for Tx and Rx DMA - 2^n for the best performance */
#define TX_BD_NUM               64
#define RX_BD_NUM               128

/* Must be shorter than length of ethtool_drvinfo.driver field to fit */
#define DRIVER_NAME             "xaxienet"
#define DRIVER_DESCRIPTION      "Xilinx Axi Ethernet driver"
#define DRIVER_VERSION          "1.00a"

#define AXIENET_REGS_N          32

/* Match table for of_platform binding */
static const struct of_device_id axienet_of_match[] = {
        { .compatible = "xlnx,axi-ethernet-1.00.a", },
        { .compatible = "xlnx,axi-ethernet-1.01.a", },
        { .compatible = "xlnx,axi-ethernet-2.01.a", },
        {},
};

MODULE_DEVICE_TABLE(of, axienet_of_match);

/* Option table for setting up Axi Ethernet hardware options */
static struct axienet_option axienet_options[] = {
        /* Turn on jumbo packet support for both Rx and Tx */
        {
                .opt = XAE_OPTION_JUMBO,
                .reg = XAE_TC_OFFSET,
                .m_or = XAE_TC_JUM_MASK,
        }, {
                .opt = XAE_OPTION_JUMBO,
                .reg = XAE_RCW1_OFFSET,
                .m_or = XAE_RCW1_JUM_MASK,
        }, { /* Turn on VLAN packet support for both Rx and Tx */
                .opt = XAE_OPTION_VLAN,
                .reg = XAE_TC_OFFSET,
                .m_or = XAE_TC_VLAN_MASK,
        }, {
                .opt = XAE_OPTION_VLAN,
                .reg = XAE_RCW1_OFFSET,
                .m_or = XAE_RCW1_VLAN_MASK,
        }, { /* Turn on FCS stripping on receive packets */
                .opt = XAE_OPTION_FCS_STRIP,
                .reg = XAE_RCW1_OFFSET,
                .m_or = XAE_RCW1_FCS_MASK,
        }, { /* Turn on FCS insertion on transmit packets */
                .opt = XAE_OPTION_FCS_INSERT,
                .reg = XAE_TC_OFFSET,
                .m_or = XAE_TC_FCS_MASK,
        }, { /* Turn off length/type field checking on receive packets */
                .opt = XAE_OPTION_LENTYPE_ERR,
                .reg = XAE_RCW1_OFFSET,
                .m_or = XAE_RCW1_LT_DIS_MASK,
        }, { /* Turn on Rx flow control */
                .opt = XAE_OPTION_FLOW_CONTROL,
                .reg = XAE_FCC_OFFSET,
                .m_or = XAE_FCC_FCRX_MASK,
        }, { /* Turn on Tx flow control */
                .opt = XAE_OPTION_FLOW_CONTROL,
                .reg = XAE_FCC_OFFSET,
                .m_or = XAE_FCC_FCTX_MASK,
        }, { /* Turn on promiscuous frame filtering */
                .opt = XAE_OPTION_PROMISC,
                .reg = XAE_FMI_OFFSET,
                .m_or = XAE_FMI_PM_MASK,
        }, { /* Enable transmitter */
                .opt = XAE_OPTION_TXEN,
                .reg = XAE_TC_OFFSET,
                .m_or = XAE_TC_TX_MASK,
        }, { /* Enable receiver */
                .opt = XAE_OPTION_RXEN,
                .reg = XAE_RCW1_OFFSET,
                .m_or = XAE_RCW1_RX_MASK,
        },
        {}
};

/**
 * axienet_dma_in32 - Memory mapped Axi DMA register read
 * @lp:         Pointer to axienet local structure
 * @reg:        Address offset from the base address of the Axi DMA core
 *
 * Return: The contents of the Axi DMA register
 *
 * This function returns the contents of the corresponding Axi DMA register.
 */
static inline u32 axienet_dma_in32(struct axienet_local *lp, off_t reg)
{
        return in_be32(lp->dma_regs + reg);
}

/**
 * axienet_dma_out32 - Memory mapped Axi DMA register write.
 * @lp:         Pointer to axienet local structure
 * @reg:        Address offset from the base address of the Axi DMA core
 * @value:      Value to be written into the Axi DMA register
 *
 * This function writes the desired value into the corresponding Axi DMA
 * register.
 */
static inline void axienet_dma_out32(struct axienet_local *lp,
                                     off_t reg, u32 value)
{
        out_be32((lp->dma_regs + reg), value);
}

/**
 * axienet_dma_bd_release - Release buffer descriptor rings
 * @ndev:       Pointer to the net_device structure
 *
 * This function is used to release the descriptors allocated in
 * axienet_dma_bd_init. axienet_dma_bd_release is called when Axi Ethernet
 * driver stop api is called.
 */
static void axienet_dma_bd_release(struct net_device *ndev)
{
        int i;
        struct axienet_local *lp = netdev_priv(ndev);

        for (i = 0; i < RX_BD_NUM; i++) {
                dma_unmap_single(ndev->dev.parent, lp->rx_bd_v[i].phys,
                                 lp->max_frm_size, DMA_FROM_DEVICE);
                dev_kfree_skb((struct sk_buff *)
                              (lp->rx_bd_v[i].sw_id_offset));
        }

        if (lp->rx_bd_v) {
                dma_free_coherent(ndev->dev.parent,
                                  sizeof(*lp->rx_bd_v) * RX_BD_NUM,
                                  lp->rx_bd_v,
                                  lp->rx_bd_p);
        }
        if (lp->tx_bd_v) {
                dma_free_coherent(ndev->dev.parent,
                                  sizeof(*lp->tx_bd_v) * TX_BD_NUM,
                                  lp->tx_bd_v,
                                  lp->tx_bd_p);
        }
}

/**
 * axienet_dma_bd_init - Setup buffer descriptor rings for Axi DMA
 * @ndev:       Pointer to the net_device structure
 *
 * Return: 0, on success -ENOMEM, on failure
 *
 * This function is called to initialize the Rx and Tx DMA descriptor
 * rings. This initializes the descriptors with required default values
 * and is called when Axi Ethernet driver reset is called.
 */
static int axienet_dma_bd_init(struct net_device *ndev)
{
        u32 cr;
        int i;
        struct sk_buff *skb;
        struct axienet_local *lp = netdev_priv(ndev);

        /* Reset the indexes which are used for accessing the BDs */
        lp->tx_bd_ci = 0;
        lp->tx_bd_tail = 0;
        lp->rx_bd_ci = 0;

        /* Allocate the Tx and Rx buffer descriptors. */
        lp->tx_bd_v = dma_zalloc_coherent(ndev->dev.parent,
                                          sizeof(*lp->tx_bd_v) * TX_BD_NUM,
                                          &lp->tx_bd_p, GFP_KERNEL);
        if (!lp->tx_bd_v)
                goto out;

        lp->rx_bd_v = dma_zalloc_coherent(ndev->dev.parent,
                                          sizeof(*lp->rx_bd_v) * RX_BD_NUM,
                                          &lp->rx_bd_p, GFP_KERNEL);
        if (!lp->rx_bd_v)
                goto out;

        for (i = 0; i < TX_BD_NUM; i++) {
                lp->tx_bd_v[i].next = lp->tx_bd_p +
                                      sizeof(*lp->tx_bd_v) *
                                      ((i + 1) % TX_BD_NUM);
        }

        for (i = 0; i < RX_BD_NUM; i++) {
                lp->rx_bd_v[i].next = lp->rx_bd_p +
                                      sizeof(*lp->rx_bd_v) *
                                      ((i + 1) % RX_BD_NUM);

                skb = netdev_alloc_skb_ip_align(ndev, lp->max_frm_size);
                if (!skb)
                        goto out;

                lp->rx_bd_v[i].sw_id_offset = (u32) skb;
                lp->rx_bd_v[i].phys = dma_map_single(ndev->dev.parent,
                                                     skb->data,
                                                     lp->max_frm_size,
                                                     DMA_FROM_DEVICE);
                lp->rx_bd_v[i].cntrl = lp->max_frm_size;
        }

        /* Start updating the Rx channel control register */
        cr = axienet_dma_in32(lp, XAXIDMA_RX_CR_OFFSET);
        /* Update the interrupt coalesce count */
        cr = ((cr & ~XAXIDMA_COALESCE_MASK) |
              ((lp->coalesce_count_rx) << XAXIDMA_COALESCE_SHIFT));
        /* Update the delay timer count */
        cr = ((cr & ~XAXIDMA_DELAY_MASK) |
              (XAXIDMA_DFT_RX_WAITBOUND << XAXIDMA_DELAY_SHIFT));
        /* Enable coalesce, delay timer and error interrupts */
        cr |= XAXIDMA_IRQ_ALL_MASK;
        /* Write to the Rx channel control register */
        axienet_dma_out32(lp, XAXIDMA_RX_CR_OFFSET, cr);

        /* Start updating the Tx channel control register */
        cr = axienet_dma_in32(lp, XAXIDMA_TX_CR_OFFSET);
        /* Update the interrupt coalesce count */
        cr = (((cr & ~XAXIDMA_COALESCE_MASK)) |
              ((lp->coalesce_count_tx) << XAXIDMA_COALESCE_SHIFT));
        /* Update the delay timer count */
        cr = (((cr & ~XAXIDMA_DELAY_MASK)) |
              (XAXIDMA_DFT_TX_WAITBOUND << XAXIDMA_DELAY_SHIFT));
        /* Enable coalesce, delay timer and error interrupts */
        cr |= XAXIDMA_IRQ_ALL_MASK;
        /* Write to the Tx channel control register */
        axienet_dma_out32(lp, XAXIDMA_TX_CR_OFFSET, cr);

        /* Populate the tail pointer and bring the Rx Axi DMA engine out of
         * halted state. This will make the Rx side ready for reception.
         */
        axienet_dma_out32(lp, XAXIDMA_RX_CDESC_OFFSET, lp->rx_bd_p);
        cr = axienet_dma_in32(lp, XAXIDMA_RX_CR_OFFSET);
        axienet_dma_out32(lp, XAXIDMA_RX_CR_OFFSET,
                          cr | XAXIDMA_CR_RUNSTOP_MASK);
        axienet_dma_out32(lp, XAXIDMA_RX_TDESC_OFFSET, lp->rx_bd_p +
                          (sizeof(*lp->rx_bd_v) * (RX_BD_NUM - 1)));

        /* Write to the RS (Run-stop) bit in the Tx channel control register.
         * Tx channel is now ready to run. But only after we write to the
         * tail pointer register that the Tx channel will start transmitting.
         */
        axienet_dma_out32(lp, XAXIDMA_TX_CDESC_OFFSET, lp->tx_bd_p);
        cr = axienet_dma_in32(lp, XAXIDMA_TX_CR_OFFSET);
        axienet_dma_out32(lp, XAXIDMA_TX_CR_OFFSET,
                          cr | XAXIDMA_CR_RUNSTOP_MASK);

        return 0;
out:
        axienet_dma_bd_release(ndev);
        return -ENOMEM;
}

/**
 * axienet_set_mac_address - Write the MAC address
 * @ndev:       Pointer to the net_device structure
 * @address:    6 byte Address to be written as MAC address
 *
 * This function is called to initialize the MAC address of the Axi Ethernet
 * core. It writes to the UAW0 and UAW1 registers of the core.
 */
static void axienet_set_mac_address(struct net_device *ndev,
                                    const void *address)
{
        struct axienet_local *lp = netdev_priv(ndev);

        if (address)
                memcpy(ndev->dev_addr, address, ETH_ALEN);
        if (!is_valid_ether_addr(ndev->dev_addr))
                eth_hw_addr_random(ndev);

        /* Set up unicast MAC address filter set its mac address */
        axienet_iow(lp, XAE_UAW0_OFFSET,
                    (ndev->dev_addr[0]) |
                    (ndev->dev_addr[1] << 8) |
                    (ndev->dev_addr[2] << 16) |
                    (ndev->dev_addr[3] << 24));
        axienet_iow(lp, XAE_UAW1_OFFSET,
                    (((axienet_ior(lp, XAE_UAW1_OFFSET)) &
                      ~XAE_UAW1_UNICASTADDR_MASK) |
                     (ndev->dev_addr[4] |
                     (ndev->dev_addr[5] << 8))));
}

/**
 * netdev_set_mac_address - Write the MAC address (from outside the driver)
 * @ndev:       Pointer to the net_device structure
 * @p:          6 byte Address to be written as MAC address
 *
 * Return: 0 for all conditions. Presently, there is no failure case.
 *
 * This function is called to initialize the MAC address of the Axi Ethernet
 * core. It calls the core specific axienet_set_mac_address. This is the
 * function that goes into net_device_ops structure entry ndo_set_mac_address.
 */
static int netdev_set_mac_address(struct net_device *ndev, void *p)
{
        struct sockaddr *addr = p;
        axienet_set_mac_address(ndev, addr->sa_data);
        return 0;
}

/**
 * axienet_set_multicast_list - Prepare the multicast table
 * @ndev:       Pointer to the net_device structure
 *
 * This function is called to initialize the multicast table during
 * initialization. The Axi Ethernet basic multicast support has a four-entry
 * multicast table which is initialized here. Additionally this function
 * goes into the net_device_ops structure entry ndo_set_multicast_list. This
 * means whenever the multicast table entries need to be updated this
 * function gets called.
 */
static void axienet_set_multicast_list(struct net_device *ndev)
{
        int i;
        u32 reg, af0reg, af1reg;
        struct axienet_local *lp = netdev_priv(ndev);

        if (ndev->flags & (IFF_ALLMULTI | IFF_PROMISC) ||
            netdev_mc_count(ndev) > XAE_MULTICAST_CAM_TABLE_NUM) {
                /* We must make the kernel realize we had to move into
                 * promiscuous mode. If it was a promiscuous mode request
                 * the flag is already set. If not we set it.
                 */
                ndev->flags |= IFF_PROMISC;
                reg = axienet_ior(lp, XAE_FMI_OFFSET);
                reg |= XAE_FMI_PM_MASK;
                axienet_iow(lp, XAE_FMI_OFFSET, reg);
                dev_info(&ndev->dev, "Promiscuous mode enabled.\n");
        } else if (!netdev_mc_empty(ndev)) {
                struct netdev_hw_addr *ha;

                i = 0;
                netdev_for_each_mc_addr(ha, ndev) {
                        if (i >= XAE_MULTICAST_CAM_TABLE_NUM)
                                break;

                        af0reg = (ha->addr[0]);
                        af0reg |= (ha->addr[1] << 8);
                        af0reg |= (ha->addr[2] << 16);
                        af0reg |= (ha->addr[3] << 24);

                        af1reg = (ha->addr[4]);
                        af1reg |= (ha->addr[5] << 8);

                        reg = axienet_ior(lp, XAE_FMI_OFFSET) & 0xFFFFFF00;
                        reg |= i;

                        axienet_iow(lp, XAE_FMI_OFFSET, reg);
                        axienet_iow(lp, XAE_AF0_OFFSET, af0reg);
                        axienet_iow(lp, XAE_AF1_OFFSET, af1reg);
                        i++;
                }
        } else {
                reg = axienet_ior(lp, XAE_FMI_OFFSET);
                reg &= ~XAE_FMI_PM_MASK;

                axienet_iow(lp, XAE_FMI_OFFSET, reg);

                for (i = 0; i < XAE_MULTICAST_CAM_TABLE_NUM; i++) {
                        reg = axienet_ior(lp, XAE_FMI_OFFSET) & 0xFFFFFF00;
                        reg |= i;

                        axienet_iow(lp, XAE_FMI_OFFSET, reg);
                        axienet_iow(lp, XAE_AF0_OFFSET, 0);
                        axienet_iow(lp, XAE_AF1_OFFSET, 0);
                }

                dev_info(&ndev->dev, "Promiscuous mode disabled.\n");
        }
}

/**
 * axienet_setoptions - Set an Axi Ethernet option
 * @ndev:       Pointer to the net_device structure
 * @options:    Option to be enabled/disabled
 *
 * The Axi Ethernet core has multiple features which can be selectively turned
 * on or off. The typical options could be jumbo frame option, basic VLAN
 * option, promiscuous mode option etc. This function is used to set or clear
 * these options in the Axi Ethernet hardware. This is done through
 * axienet_option structure .
 */
static void axienet_setoptions(struct net_device *ndev, u32 options)
{
        int reg;
        struct axienet_local *lp = netdev_priv(ndev);
        struct axienet_option *tp = &axienet_options[0];

        while (tp->opt) {
                reg = ((axienet_ior(lp, tp->reg)) & ~(tp->m_or));
                if (options & tp->opt)
                        reg |= tp->m_or;
                axienet_iow(lp, tp->reg, reg);
                tp++;
        }

        lp->options |= options;
}

static void __axienet_device_reset(struct axienet_local *lp, off_t offset)
{
        u32 timeout;
        /* Reset Axi DMA. This would reset Axi Ethernet core as well. The reset
         * process of Axi DMA takes a while to complete as all pending
         * commands/transfers will be flushed or completed during this
         * reset process.
         */
        axienet_dma_out32(lp, offset, XAXIDMA_CR_RESET_MASK);
        timeout = DELAY_OF_ONE_MILLISEC;
        while (axienet_dma_in32(lp, offset) & XAXIDMA_CR_RESET_MASK) {
                udelay(1);
                if (--timeout == 0) {
                        netdev_err(lp->ndev, "%s: DMA reset timeout!\n",
                                   __func__);
                        break;
                }
        }
}

/**
 * axienet_device_reset - Reset and initialize the Axi Ethernet hardware.
 * @ndev:       Pointer to the net_device structure
 *
 * This function is called to reset and initialize the Axi Ethernet core. This
 * is typically called during initialization. It does a reset of the Axi DMA
 * Rx/Tx channels and initializes the Axi DMA BDs. Since Axi DMA reset lines
 * areconnected to Axi Ethernet reset lines, this in turn resets the Axi
 * Ethernet core. No separate hardware reset is done for the Axi Ethernet
 * core.
 */
static void axienet_device_reset(struct net_device *ndev)
{
        u32 axienet_status;
        struct axienet_local *lp = netdev_priv(ndev);

        __axienet_device_reset(lp, XAXIDMA_TX_CR_OFFSET);
        __axienet_device_reset(lp, XAXIDMA_RX_CR_OFFSET);

        lp->max_frm_size = XAE_MAX_VLAN_FRAME_SIZE;
        lp->options |= XAE_OPTION_VLAN;
        lp->options &= (~XAE_OPTION_JUMBO);

        if ((ndev->mtu > XAE_MTU) &&
                (ndev->mtu <= XAE_JUMBO_MTU)) {
                lp->max_frm_size = ndev->mtu + VLAN_ETH_HLEN +
                                        XAE_TRL_SIZE;

                if (lp->max_frm_size <= lp->rxmem)
                        lp->options |= XAE_OPTION_JUMBO;
        }

        if (axienet_dma_bd_init(ndev)) {
                netdev_err(ndev, "%s: descriptor allocation failed\n",
                           __func__);
        }

        axienet_status = axienet_ior(lp, XAE_RCW1_OFFSET);
        axienet_status &= ~XAE_RCW1_RX_MASK;
        axienet_iow(lp, XAE_RCW1_OFFSET, axienet_status);

        axienet_status = axienet_ior(lp, XAE_IP_OFFSET);
        if (axienet_status & XAE_INT_RXRJECT_MASK)
                axienet_iow(lp, XAE_IS_OFFSET, XAE_INT_RXRJECT_MASK);

        axienet_iow(lp, XAE_FCC_OFFSET, XAE_FCC_FCRX_MASK);

        /* Sync default options with HW but leave receiver and
         * transmitter disabled.
         */
        axienet_setoptions(ndev, lp->options &
                           ~(XAE_OPTION_TXEN | XAE_OPTION_RXEN));
        axienet_set_mac_address(ndev, NULL);
        axienet_set_multicast_list(ndev);
        axienet_setoptions(ndev, lp->options);

        netif_trans_update(ndev);
}

/**
 * axienet_adjust_link - Adjust the PHY link speed/duplex.
 * @ndev:       Pointer to the net_device structure
 *
 * This function is called to change the speed and duplex setting after
 * auto negotiation is done by the PHY. This is the function that gets
 * registered with the PHY interface through the "of_phy_connect" call.
 */
static void axienet_adjust_link(struct net_device *ndev)
{
        u32 emmc_reg;
        u32 link_state;
        u32 setspeed = 1;
        struct axienet_local *lp = netdev_priv(ndev);
        struct phy_device *phy = ndev->phydev;

        link_state = phy->speed | (phy->duplex << 1) | phy->link;
        if (lp->last_link != link_state) {
                if ((phy->speed == SPEED_10) || (phy->speed == SPEED_100)) {
                        if (lp->phy_type == XAE_PHY_TYPE_1000BASE_X)
                                setspeed = 0;
                } else {
                        if ((phy->speed == SPEED_1000) &&
                            (lp->phy_type == XAE_PHY_TYPE_MII))
                                setspeed = 0;
                }

                if (setspeed == 1) {
                        emmc_reg = axienet_ior(lp, XAE_EMMC_OFFSET);
                        emmc_reg &= ~XAE_EMMC_LINKSPEED_MASK;

                        switch (phy->speed) {
                        case SPEED_1000:
                                emmc_reg |= XAE_EMMC_LINKSPD_1000;
                                break;
                        case SPEED_100:
                                emmc_reg |= XAE_EMMC_LINKSPD_100;
                                break;
                        case SPEED_10:
                                emmc_reg |= XAE_EMMC_LINKSPD_10;
                                break;
                        default:
                                dev_err(&ndev->dev, "Speed other than 10, 100 "
                                        "or 1Gbps is not supported\n");
                                break;
                        }

                        axienet_iow(lp, XAE_EMMC_OFFSET, emmc_reg);
                        lp->last_link = link_state;
                        phy_print_status(phy);
                } else {
                        netdev_err(ndev,
                                   "Error setting Axi Ethernet mac speed\n");
                }
        }
}

/**
 * axienet_start_xmit_done - Invoked once a transmit is completed by the
 * Axi DMA Tx channel.
 * @ndev:       Pointer to the net_device structure
 *
 * This function is invoked from the Axi DMA Tx isr to notify the completion
 * of transmit operation. It clears fields in the corresponding Tx BDs and
 * unmaps the corresponding buffer so that CPU can regain ownership of the
 * buffer. It finally invokes "netif_wake_queue" to restart transmission if
 * required.
 */
static void axienet_start_xmit_done(struct net_device *ndev)
{
        u32 size = 0;
        u32 packets = 0;
        struct axienet_local *lp = netdev_priv(ndev);
        struct axidma_bd *cur_p;
        unsigned int status = 0;

        cur_p = &lp->tx_bd_v[lp->tx_bd_ci];
        status = cur_p->status;
        while (status & XAXIDMA_BD_STS_COMPLETE_MASK) {
                dma_unmap_single(ndev->dev.parent, cur_p->phys,
                                (cur_p->cntrl & XAXIDMA_BD_CTRL_LENGTH_MASK),
                                DMA_TO_DEVICE);
                if (cur_p->app4)
                        dev_kfree_skb_irq((struct sk_buff *)cur_p->app4);
                /*cur_p->phys = 0;*/
                cur_p->app0 = 0;
                cur_p->app1 = 0;
                cur_p->app2 = 0;
                cur_p->app4 = 0;
                cur_p->status = 0;

                size += status & XAXIDMA_BD_STS_ACTUAL_LEN_MASK;
                packets++;

                ++lp->tx_bd_ci;
                lp->tx_bd_ci %= TX_BD_NUM;
                cur_p = &lp->tx_bd_v[lp->tx_bd_ci];
                status = cur_p->status;
        }

        ndev->stats.tx_packets += packets;
        ndev->stats.tx_bytes += size;
        netif_wake_queue(ndev);
}

/**
 * axienet_check_tx_bd_space - Checks if a BD/group of BDs are currently busy
 * @lp:         Pointer to the axienet_local structure
 * @num_frag:   The number of BDs to check for
 *
 * Return: 0, on success
 *          NETDEV_TX_BUSY, if any of the descriptors are not free
 *
 * This function is invoked before BDs are allocated and transmission starts.
 * This function returns 0 if a BD or group of BDs can be allocated for
 * transmission. If the BD or any of the BDs are not free the function
 * returns a busy status. This is invoked from axienet_start_xmit.
 */
static inline int axienet_check_tx_bd_space(struct axienet_local *lp,
                                            int num_frag)
{
        struct axidma_bd *cur_p;
        cur_p = &lp->tx_bd_v[(lp->tx_bd_tail + num_frag) % TX_BD_NUM];
        if (cur_p->status & XAXIDMA_BD_STS_ALL_MASK)
                return NETDEV_TX_BUSY;
        return 0;
}

/**
 * axienet_start_xmit - Starts the transmission.
 * @skb:        sk_buff pointer that contains data to be Txed.
 * @ndev:       Pointer to net_device structure.
 *
 * Return: NETDEV_TX_OK, on success
 *          NETDEV_TX_BUSY, if any of the descriptors are not free
 *
 * This function is invoked from upper layers to initiate transmission. The
 * function uses the next available free BDs and populates their fields to
 * start the transmission. Additionally if checksum offloading is supported,
 * it populates AXI Stream Control fields with appropriate values.
 */
static int axienet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
{
        u32 ii;
        u32 num_frag;
        u32 csum_start_off;
        u32 csum_index_off;
        skb_frag_t *frag;
        dma_addr_t tail_p;
        struct axienet_local *lp = netdev_priv(ndev);
        struct axidma_bd *cur_p;

        num_frag = skb_shinfo(skb)->nr_frags;
        cur_p = &lp->tx_bd_v[lp->tx_bd_tail];

        if (axienet_check_tx_bd_space(lp, num_frag)) {
                if (!netif_queue_stopped(ndev))
                        netif_stop_queue(ndev);
                return NETDEV_TX_BUSY;
        }

        if (skb->ip_summed == CHECKSUM_PARTIAL) {
                if (lp->features & XAE_FEATURE_FULL_TX_CSUM) {
                        /* Tx Full Checksum Offload Enabled */
                        cur_p->app0 |= 2;
                } else if (lp->features & XAE_FEATURE_PARTIAL_RX_CSUM) {
                        csum_start_off = skb_transport_offset(skb);
                        csum_index_off = csum_start_off + skb->csum_offset;
                        /* Tx Partial Checksum Offload Enabled */
                        cur_p->app0 |= 1;
                        cur_p->app1 = (csum_start_off << 16) | csum_index_off;
                }
        } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
                cur_p->app0 |= 2; /* Tx Full Checksum Offload Enabled */
        }

        cur_p->cntrl = skb_headlen(skb) | XAXIDMA_BD_CTRL_TXSOF_MASK;
        cur_p->phys = dma_map_single(ndev->dev.parent, skb->data,
                                     skb_headlen(skb), DMA_TO_DEVICE);

        for (ii = 0; ii < num_frag; ii++) {
                ++lp->tx_bd_tail;
                lp->tx_bd_tail %= TX_BD_NUM;
                cur_p = &lp->tx_bd_v[lp->tx_bd_tail];
                frag = &skb_shinfo(skb)->frags[ii];
                cur_p->phys = dma_map_single(ndev->dev.parent,
                                             skb_frag_address(frag),
                                             skb_frag_size(frag),
                                             DMA_TO_DEVICE);
                cur_p->cntrl = skb_frag_size(frag);
        }

        cur_p->cntrl |= XAXIDMA_BD_CTRL_TXEOF_MASK;
        cur_p->app4 = (unsigned long)skb;

        tail_p = lp->tx_bd_p + sizeof(*lp->tx_bd_v) * lp->tx_bd_tail;
        /* Start the transfer */
        axienet_dma_out32(lp, XAXIDMA_TX_TDESC_OFFSET, tail_p);
        ++lp->tx_bd_tail;
        lp->tx_bd_tail %= TX_BD_NUM;

        return NETDEV_TX_OK;
}

/**
 * axienet_recv - Is called from Axi DMA Rx Isr to complete the received
 *                BD processing.
 * @ndev:       Pointer to net_device structure.
 *
 * This function is invoked from the Axi DMA Rx isr to process the Rx BDs. It
 * does minimal processing and invokes "netif_rx" to complete further
 * processing.
 */
static void axienet_recv(struct net_device *ndev)
{
        u32 length;
        u32 csumstatus;
        u32 size = 0;
        u32 packets = 0;
        dma_addr_t tail_p = 0;
        struct axienet_local *lp = netdev_priv(ndev);
        struct sk_buff *skb, *new_skb;
        struct axidma_bd *cur_p;

        cur_p = &lp->rx_bd_v[lp->rx_bd_ci];

        while ((cur_p->status & XAXIDMA_BD_STS_COMPLETE_MASK)) {
                tail_p = lp->rx_bd_p + sizeof(*lp->rx_bd_v) * lp->rx_bd_ci;
                skb = (struct sk_buff *) (cur_p->sw_id_offset);
                length = cur_p->app4 & 0x0000FFFF;

                dma_unmap_single(ndev->dev.parent, cur_p->phys,
                                 lp->max_frm_size,
                                 DMA_FROM_DEVICE);

                skb_put(skb, length);
                skb->protocol = eth_type_trans(skb, ndev);
                /*skb_checksum_none_assert(skb);*/
                skb->ip_summed = CHECKSUM_NONE;

                /* if we're doing Rx csum offload, set it up */
                if (lp->features & XAE_FEATURE_FULL_RX_CSUM) {
                        csumstatus = (cur_p->app2 &
                                      XAE_FULL_CSUM_STATUS_MASK) >> 3;
                        if ((csumstatus == XAE_IP_TCP_CSUM_VALIDATED) ||
                            (csumstatus == XAE_IP_UDP_CSUM_VALIDATED)) {
                                skb->ip_summed = CHECKSUM_UNNECESSARY;
                        }
                } else if ((lp->features & XAE_FEATURE_PARTIAL_RX_CSUM) != 0 &&
                           skb->protocol == htons(ETH_P_IP) &&
                           skb->len > 64) {
                        skb->csum = be32_to_cpu(cur_p->app3 & 0xFFFF);
                        skb->ip_summed = CHECKSUM_COMPLETE;
                }

                netif_rx(skb);

                size += length;
                packets++;

                new_skb = netdev_alloc_skb_ip_align(ndev, lp->max_frm_size);
                if (!new_skb)
                        return;

                cur_p->phys = dma_map_single(ndev->dev.parent, new_skb->data,
                                             lp->max_frm_size,
                                             DMA_FROM_DEVICE);
                cur_p->cntrl = lp->max_frm_size;
                cur_p->status = 0;
                cur_p->sw_id_offset = (u32) new_skb;

                ++lp->rx_bd_ci;
                lp->rx_bd_ci %= RX_BD_NUM;
                cur_p = &lp->rx_bd_v[lp->rx_bd_ci];
        }

        ndev->stats.rx_packets += packets;
        ndev->stats.rx_bytes += size;

        if (tail_p)
                axienet_dma_out32(lp, XAXIDMA_RX_TDESC_OFFSET, tail_p);
}

/**
 * axienet_tx_irq - Tx Done Isr.
 * @irq:        irq number
 * @_ndev:      net_device pointer
 *
 * Return: IRQ_HANDLED for all cases.
 *
 * This is the Axi DMA Tx done Isr. It invokes "axienet_start_xmit_done"
 * to complete the BD processing.
 */
static irqreturn_t axienet_tx_irq(int irq, void *_ndev)
{
        u32 cr;
        unsigned int status;
        struct net_device *ndev = _ndev;
        struct axienet_local *lp = netdev_priv(ndev);

        status = axienet_dma_in32(lp, XAXIDMA_TX_SR_OFFSET);
        if (status & (XAXIDMA_IRQ_IOC_MASK | XAXIDMA_IRQ_DELAY_MASK)) {
                axienet_dma_out32(lp, XAXIDMA_TX_SR_OFFSET, status);
                axienet_start_xmit_done(lp->ndev);
                goto out;
        }
        if (!(status & XAXIDMA_IRQ_ALL_MASK))
                dev_err(&ndev->dev, "No interrupts asserted in Tx path\n");
        if (status & XAXIDMA_IRQ_ERROR_MASK) {
                dev_err(&ndev->dev, "DMA Tx error 0x%x\n", status);
                dev_err(&ndev->dev, "Current BD is at: 0x%x\n",
                        (lp->tx_bd_v[lp->tx_bd_ci]).phys);

                cr = axienet_dma_in32(lp, XAXIDMA_TX_CR_OFFSET);
                /* Disable coalesce, delay timer and error interrupts */
                cr &= (~XAXIDMA_IRQ_ALL_MASK);
                /* Write to the Tx channel control register */
                axienet_dma_out32(lp, XAXIDMA_TX_CR_OFFSET, cr);

                cr = axienet_dma_in32(lp, XAXIDMA_RX_CR_OFFSET);
                /* Disable coalesce, delay timer and error interrupts */
                cr &= (~XAXIDMA_IRQ_ALL_MASK);
                /* Write to the Rx channel control register */
                axienet_dma_out32(lp, XAXIDMA_RX_CR_OFFSET, cr);

                tasklet_schedule(&lp->dma_err_tasklet);
                axienet_dma_out32(lp, XAXIDMA_TX_SR_OFFSET, status);
        }
out:
        return IRQ_HANDLED;
}

/**
 * axienet_rx_irq - Rx Isr.
 * @irq:        irq number
 * @_ndev:      net_device pointer
 *
 * Return: IRQ_HANDLED for all cases.
 *
 * This is the Axi DMA Rx Isr. It invokes "axienet_recv" to complete the BD
 * processing.
 */
static irqreturn_t axienet_rx_irq(int irq, void *_ndev)
{
        u32 cr;
        unsigned int status;
        struct net_device *ndev = _ndev;
        struct axienet_local *lp = netdev_priv(ndev);

        status = axienet_dma_in32(lp, XAXIDMA_RX_SR_OFFSET);
        if (status & (XAXIDMA_IRQ_IOC_MASK | XAXIDMA_IRQ_DELAY_MASK)) {
                axienet_dma_out32(lp, XAXIDMA_RX_SR_OFFSET, status);
                axienet_recv(lp->ndev);
                goto out;
        }
        if (!(status & XAXIDMA_IRQ_ALL_MASK))
                dev_err(&ndev->dev, "No interrupts asserted in Rx path\n");
        if (status & XAXIDMA_IRQ_ERROR_MASK) {
                dev_err(&ndev->dev, "DMA Rx error 0x%x\n", status);
                dev_err(&ndev->dev, "Current BD is at: 0x%x\n",
                        (lp->rx_bd_v[lp->rx_bd_ci]).phys);

                cr = axienet_dma_in32(lp, XAXIDMA_TX_CR_OFFSET);
                /* Disable coalesce, delay timer and error interrupts */
                cr &= (~XAXIDMA_IRQ_ALL_MASK);
                /* Finally write to the Tx channel control register */
                axienet_dma_out32(lp, XAXIDMA_TX_CR_OFFSET, cr);

                cr = axienet_dma_in32(lp, XAXIDMA_RX_CR_OFFSET);
                /* Disable coalesce, delay timer and error interrupts */
                cr &= (~XAXIDMA_IRQ_ALL_MASK);
                /* write to the Rx channel control register */
                axienet_dma_out32(lp, XAXIDMA_RX_CR_OFFSET, cr);

                tasklet_schedule(&lp->dma_err_tasklet);
                axienet_dma_out32(lp, XAXIDMA_RX_SR_OFFSET, status);
        }
out:
        return IRQ_HANDLED;
}

static void axienet_dma_err_handler(unsigned long data);

/**
 * axienet_open - Driver open routine.
 * @ndev:       Pointer to net_device structure
 *
 * Return: 0, on success.
 *          -ENODEV, if PHY cannot be connected to
 *          non-zero error value on failure
 *
 * This is the driver open routine. It calls phy_start to start the PHY device.
 * It also allocates interrupt service routines, enables the interrupt lines
 * and ISR handling. Axi Ethernet core is reset through Axi DMA core. Buffer
 * descriptors are initialized.
 */
static int axienet_open(struct net_device *ndev)
{
        int ret, mdio_mcreg;
        struct axienet_local *lp = netdev_priv(ndev);
        struct phy_device *phydev = NULL;

        dev_dbg(&ndev->dev, "axienet_open()\n");

        mdio_mcreg = axienet_ior(lp, XAE_MDIO_MC_OFFSET);
        ret = axienet_mdio_wait_until_ready(lp);
        if (ret < 0)
                return ret;
        /* Disable the MDIO interface till Axi Ethernet Reset is completed.
         * When we do an Axi Ethernet reset, it resets the complete core
         * including the MDIO. If MDIO is not disabled when the reset
         * process is started, MDIO will be broken afterwards.
         */
        axienet_iow(lp, XAE_MDIO_MC_OFFSET,
                    (mdio_mcreg & (~XAE_MDIO_MC_MDIOEN_MASK)));
        axienet_device_reset(ndev);
        /* Enable the MDIO */
        axienet_iow(lp, XAE_MDIO_MC_OFFSET, mdio_mcreg);
        ret = axienet_mdio_wait_until_ready(lp);
        if (ret < 0)
                return ret;

        if (lp->phy_node) {
                if (lp->phy_type == XAE_PHY_TYPE_GMII) {
                        phydev = of_phy_connect(lp->ndev, lp->phy_node,
                                                axienet_adjust_link, 0,
                                                PHY_INTERFACE_MODE_GMII);
                } else if (lp->phy_type == XAE_PHY_TYPE_RGMII_2_0) {
                        phydev = of_phy_connect(lp->ndev, lp->phy_node,
                                                axienet_adjust_link, 0,
                                                PHY_INTERFACE_MODE_RGMII_ID);
                }

                if (!phydev)
                        dev_err(lp->dev, "of_phy_connect() failed\n");
                else
                        phy_start(phydev);
        }

        /* Enable tasklets for Axi DMA error handling */
        tasklet_init(&lp->dma_err_tasklet, axienet_dma_err_handler,
                     (unsigned long) lp);

        /* Enable interrupts for Axi DMA Tx */
        ret = request_irq(lp->tx_irq, axienet_tx_irq, 0, ndev->name, ndev);
        if (ret)
                goto err_tx_irq;
        /* Enable interrupts for Axi DMA Rx */
        ret = request_irq(lp->rx_irq, axienet_rx_irq, 0, ndev->name, ndev);
        if (ret)
                goto err_rx_irq;

        return 0;

err_rx_irq:
        free_irq(lp->tx_irq, ndev);
err_tx_irq:
        if (phydev)
                phy_disconnect(phydev);
        tasklet_kill(&lp->dma_err_tasklet);
        dev_err(lp->dev, "request_irq() failed\n");
        return ret;
}

/**
 * axienet_stop - Driver stop routine.
 * @ndev:       Pointer to net_device structure
 *
 * Return: 0, on success.
 *
 * This is the driver stop routine. It calls phy_disconnect to stop the PHY
 * device. It also removes the interrupt handlers and disables the interrupts.
 * The Axi DMA Tx/Rx BDs are released.
 */
static int axienet_stop(struct net_device *ndev)
{
        u32 cr;
        struct axienet_local *lp = netdev_priv(ndev);

        dev_dbg(&ndev->dev, "axienet_close()\n");

        cr = axienet_dma_in32(lp, XAXIDMA_RX_CR_OFFSET);
        axienet_dma_out32(lp, XAXIDMA_RX_CR_OFFSET,
                          cr & (~XAXIDMA_CR_RUNSTOP_MASK));
        cr = axienet_dma_in32(lp, XAXIDMA_TX_CR_OFFSET);
        axienet_dma_out32(lp, XAXIDMA_TX_CR_OFFSET,

                          cr & (~XAXIDMA_CR_RUNSTOP_MASK));
        axienet_setoptions(ndev, lp->options &
                           ~(XAE_OPTION_TXEN | XAE_OPTION_RXEN));

        tasklet_kill(&lp->dma_err_tasklet);

        free_irq(lp->tx_irq, ndev);
        free_irq(lp->rx_irq, ndev);

        if (ndev->phydev)
                phy_disconnect(ndev->phydev);

        axienet_dma_bd_release(ndev);
        return 0;
}

/**
 * axienet_change_mtu - Driver change mtu routine.
 * @ndev:       Pointer to net_device structure
 * @new_mtu:    New mtu value to be applied
 *
 * Return: Always returns 0 (success).
 *
 * This is the change mtu driver routine. It checks if the Axi Ethernet
 * hardware supports jumbo frames before changing the mtu. This can be
 * called only when the device is not up.
 */
static int axienet_change_mtu(struct net_device *ndev, int new_mtu)
{
        struct axienet_local *lp = netdev_priv(ndev);

        if (netif_running(ndev))
                return -EBUSY;

        if ((new_mtu + VLAN_ETH_HLEN +
                XAE_TRL_SIZE) > lp->rxmem)
                return -EINVAL;

        ndev->mtu = new_mtu;

        return 0;
}

#ifdef CONFIG_NET_POLL_CONTROLLER
/**
 * axienet_poll_controller - Axi Ethernet poll mechanism.
 * @ndev:       Pointer to net_device structure
 *
 * This implements Rx/Tx ISR poll mechanisms. The interrupts are disabled prior
 * to polling the ISRs and are enabled back after the polling is done.
 */
static void axienet_poll_controller(struct net_device *ndev)
{
        struct axienet_local *lp = netdev_priv(ndev);
        disable_irq(lp->tx_irq);
        disable_irq(lp->rx_irq);
        axienet_rx_irq(lp->tx_irq, ndev);
        axienet_tx_irq(lp->rx_irq, ndev);
        enable_irq(lp->tx_irq);
        enable_irq(lp->rx_irq);
}
#endif

static const struct net_device_ops axienet_netdev_ops = {
        .ndo_open = axienet_open,
        .ndo_stop = axienet_stop,
        .ndo_start_xmit = axienet_start_xmit,
        .ndo_change_mtu = axienet_change_mtu,
        .ndo_set_mac_address = netdev_set_mac_address,
        .ndo_validate_addr = eth_validate_addr,
        .ndo_set_rx_mode = axienet_set_multicast_list,
#ifdef CONFIG_NET_POLL_CONTROLLER
        .ndo_poll_controller = axienet_poll_controller,
#endif
};

/**
 * axienet_ethtools_get_drvinfo - Get various Axi Ethernet driver information.
 * @ndev:       Pointer to net_device structure
 * @ed:         Pointer to ethtool_drvinfo structure
 *
 * This implements ethtool command for getting the driver information.
 * Issue "ethtool -i ethX" under linux prompt to execute this function.
 */
static void axienet_ethtools_get_drvinfo(struct net_device *ndev,
                                         struct ethtool_drvinfo *ed)
{
        strlcpy(ed->driver, DRIVER_NAME, sizeof(ed->driver));
        strlcpy(ed->version, DRIVER_VERSION, sizeof(ed->version));
}

/**
 * axienet_ethtools_get_regs_len - Get the total regs length present in the
 *                                 AxiEthernet core.
 * @ndev:       Pointer to net_device structure
 *
 * This implements ethtool command for getting the total register length
 * information.
 *
 * Return: the total regs length
 */
static int axienet_ethtools_get_regs_len(struct net_device *ndev)
{
        return sizeof(u32) * AXIENET_REGS_N;
}

/**
 * axienet_ethtools_get_regs - Dump the contents of all registers present
 *                             in AxiEthernet core.
 * @ndev:       Pointer to net_device structure
 * @regs:       Pointer to ethtool_regs structure
 * @ret:        Void pointer used to return the contents of the registers.
 *
 * This implements ethtool command for getting the Axi Ethernet register dump.
 * Issue "ethtool -d ethX" to execute this function.
 */
static void axienet_ethtools_get_regs(struct net_device *ndev,
                                      struct ethtool_regs *regs, void *ret)
{
        u32 *data = (u32 *) ret;
        size_t len = sizeof(u32) * AXIENET_REGS_N;
        struct axienet_local *lp = netdev_priv(ndev);

        regs->version = 0;
        regs->len = len;

        memset(data, 0, len);
        data[0] = axienet_ior(lp, XAE_RAF_OFFSET);
        data[1] = axienet_ior(lp, XAE_TPF_OFFSET);
        data[2] = axienet_ior(lp, XAE_IFGP_OFFSET);
        data[3] = axienet_ior(lp, XAE_IS_OFFSET);
        data[4] = axienet_ior(lp, XAE_IP_OFFSET);
        data[5] = axienet_ior(lp, XAE_IE_OFFSET);
        data[6] = axienet_ior(lp, XAE_TTAG_OFFSET);
        data[7] = axienet_ior(lp, XAE_RTAG_OFFSET);
        data[8] = axienet_ior(lp, XAE_UAWL_OFFSET);
        data[9] = axienet_ior(lp, XAE_UAWU_OFFSET);
        data[10] = axienet_ior(lp, XAE_TPID0_OFFSET);
        data[11] = axienet_ior(lp, XAE_TPID1_OFFSET);
        data[12] = axienet_ior(lp, XAE_PPST_OFFSET);
        data[13] = axienet_ior(lp, XAE_RCW0_OFFSET);
        data[14] = axienet_ior(lp, XAE_RCW1_OFFSET);
        data[15] = axienet_ior(lp, XAE_TC_OFFSET);
        data[16] = axienet_ior(lp, XAE_FCC_OFFSET);
        data[17] = axienet_ior(lp, XAE_EMMC_OFFSET);
        data[18] = axienet_ior(lp, XAE_PHYC_OFFSET);
        data[19] = axienet_ior(lp, XAE_MDIO_MC_OFFSET);
        data[20] = axienet_ior(lp, XAE_MDIO_MCR_OFFSET);
        data[21] = axienet_ior(lp, XAE_MDIO_MWD_OFFSET);
        data[22] = axienet_ior(lp, XAE_MDIO_MRD_OFFSET);
        data[23] = axienet_ior(lp, XAE_MDIO_MIS_OFFSET);
        data[24] = axienet_ior(lp, XAE_MDIO_MIP_OFFSET);
        data[25] = axienet_ior(lp, XAE_MDIO_MIE_OFFSET);
        data[26] = axienet_ior(lp, XAE_MDIO_MIC_OFFSET);
        data[27] = axienet_ior(lp, XAE_UAW0_OFFSET);
        data[28] = axienet_ior(lp, XAE_UAW1_OFFSET);
        data[29] = axienet_ior(lp, XAE_FMI_OFFSET);
        data[30] = axienet_ior(lp, XAE_AF0_OFFSET);
        data[31] = axienet_ior(lp, XAE_AF1_OFFSET);
}

/**
 * axienet_ethtools_get_pauseparam - Get the pause parameter setting for
 *                                   Tx and Rx paths.
 * @ndev:       Pointer to net_device structure
 * @epauseparm: Pointer to ethtool_pauseparam structure.
 *
 * This implements ethtool command for getting axi ethernet pause frame
 * setting. Issue "ethtool -a ethX" to execute this function.
 */
static void
axienet_ethtools_get_pauseparam(struct net_device *ndev,
                                struct ethtool_pauseparam *epauseparm)
{
        u32 regval;
        struct axienet_local *lp = netdev_priv(ndev);
        epauseparm->autoneg  = 0;
        regval = axienet_ior(lp, XAE_FCC_OFFSET);
        epauseparm->tx_pause = regval & XAE_FCC_FCTX_MASK;
        epauseparm->rx_pause = regval & XAE_FCC_FCRX_MASK;
}

/**
 * axienet_ethtools_set_pauseparam - Set device pause parameter(flow control)
 *                                   settings.
 * @ndev:       Pointer to net_device structure
 * @epauseparm:Pointer to ethtool_pauseparam structure
 *
 * This implements ethtool command for enabling flow control on Rx and Tx
 * paths. Issue "ethtool -A ethX tx on|off" under linux prompt to execute this
 * function.
 *
 * Return: 0 on success, -EFAULT if device is running
 */
static int
axienet_ethtools_set_pauseparam(struct net_device *ndev,
                                struct ethtool_pauseparam *epauseparm)
{
        u32 regval = 0;
        struct axienet_local *lp = netdev_priv(ndev);

        if (netif_running(ndev)) {
                netdev_err(ndev,
                           "Please stop netif before applying configuration\n");
                return -EFAULT;
        }

        regval = axienet_ior(lp, XAE_FCC_OFFSET);
        if (epauseparm->tx_pause)
                regval |= XAE_FCC_FCTX_MASK;
        else
                regval &= ~XAE_FCC_FCTX_MASK;
        if (epauseparm->rx_pause)
                regval |= XAE_FCC_FCRX_MASK;
        else
                regval &= ~XAE_FCC_FCRX_MASK;
        axienet_iow(lp, XAE_FCC_OFFSET, regval);

        return 0;
}

/**
 * axienet_ethtools_get_coalesce - Get DMA interrupt coalescing count.
 * @ndev:       Pointer to net_device structure
 * @ecoalesce:  Pointer to ethtool_coalesce structure
 *
 * This implements ethtool command for getting the DMA interrupt coalescing
 * count on Tx and Rx paths. Issue "ethtool -c ethX" under linux prompt to
 * execute this function.
 *
 * Return: 0 always
 */
static int axienet_ethtools_get_coalesce(struct net_device *ndev,
                                         struct ethtool_coalesce *ecoalesce)
{
        u32 regval = 0;
        struct axienet_local *lp = netdev_priv(ndev);
        regval = axienet_dma_in32(lp, XAXIDMA_RX_CR_OFFSET);
        ecoalesce->rx_max_coalesced_frames = (regval & XAXIDMA_COALESCE_MASK)
                                             >> XAXIDMA_COALESCE_SHIFT;
        regval = axienet_dma_in32(lp, XAXIDMA_TX_CR_OFFSET);
        ecoalesce->tx_max_coalesced_frames = (regval & XAXIDMA_COALESCE_MASK)
                                             >> XAXIDMA_COALESCE_SHIFT;
        return 0;
}

/**
 * axienet_ethtools_set_coalesce - Set DMA interrupt coalescing count.
 * @ndev:       Pointer to net_device structure
 * @ecoalesce:  Pointer to ethtool_coalesce structure
 *
 * This implements ethtool command for setting the DMA interrupt coalescing
 * count on Tx and Rx paths. Issue "ethtool -C ethX rx-frames 5" under linux
 * prompt to execute this function.
 *
 * Return: 0, on success, Non-zero error value on failure.
 */
static int axienet_ethtools_set_coalesce(struct net_device *ndev,
                                         struct ethtool_coalesce *ecoalesce)
{
        struct axienet_local *lp = netdev_priv(ndev);

        if (netif_running(ndev)) {
                netdev_err(ndev,
                           "Please stop netif before applying configuration\n");
                return -EFAULT;
        }

        if ((ecoalesce->rx_coalesce_usecs) ||
            (ecoalesce->rx_coalesce_usecs_irq) ||
            (ecoalesce->rx_max_coalesced_frames_irq) ||
            (ecoalesce->tx_coalesce_usecs) ||
            (ecoalesce->tx_coalesce_usecs_irq) ||
            (ecoalesce->tx_max_coalesced_frames_irq) ||
            (ecoalesce->stats_block_coalesce_usecs) ||
            (ecoalesce->use_adaptive_rx_coalesce) ||
            (ecoalesce->use_adaptive_tx_coalesce) ||
            (ecoalesce->pkt_rate_low) ||
            (ecoalesce->rx_coalesce_usecs_low) ||
            (ecoalesce->rx_max_coalesced_frames_low) ||
            (ecoalesce->tx_coalesce_usecs_low) ||
            (ecoalesce->tx_max_coalesced_frames_low) ||
            (ecoalesce->pkt_rate_high) ||
            (ecoalesce->rx_coalesce_usecs_high) ||
            (ecoalesce->rx_max_coalesced_frames_high) ||
            (ecoalesce->tx_coalesce_usecs_high) ||
            (ecoalesce->tx_max_coalesced_frames_high) ||
            (ecoalesce->rate_sample_interval))
                return -EOPNOTSUPP;
        if (ecoalesce->rx_max_coalesced_frames)
                lp->coalesce_count_rx = ecoalesce->rx_max_coalesced_frames;
        if (ecoalesce->tx_max_coalesced_frames)
                lp->coalesce_count_tx = ecoalesce->tx_max_coalesced_frames;

        return 0;
}

static const struct ethtool_ops axienet_ethtool_ops = {
        .get_drvinfo    = axienet_ethtools_get_drvinfo,
        .get_regs_len   = axienet_ethtools_get_regs_len,
        .get_regs       = axienet_ethtools_get_regs,
        .get_link       = ethtool_op_get_link,
        .get_pauseparam = axienet_ethtools_get_pauseparam,
        .set_pauseparam = axienet_ethtools_set_pauseparam,
        .get_coalesce   = axienet_ethtools_get_coalesce,
        .set_coalesce   = axienet_ethtools_set_coalesce,
        .get_link_ksettings = phy_ethtool_get_link_ksettings,
        .set_link_ksettings = phy_ethtool_set_link_ksettings,
};

/**
 * axienet_dma_err_handler - Tasklet handler for Axi DMA Error
 * @data:       Data passed
 *
 * Resets the Axi DMA and Axi Ethernet devices, and reconfigures the
 * Tx/Rx BDs.
 */
static void axienet_dma_err_handler(unsigned long data)
{
        u32 axienet_status;
        u32 cr, i;
        int mdio_mcreg;
        struct axienet_local *lp = (struct axienet_local *) data;
        struct net_device *ndev = lp->ndev;
        struct axidma_bd *cur_p;

        axienet_setoptions(ndev, lp->options &
                           ~(XAE_OPTION_TXEN | XAE_OPTION_RXEN));
        mdio_mcreg = axienet_ior(lp, XAE_MDIO_MC_OFFSET);
        axienet_mdio_wait_until_ready(lp);
        /* Disable the MDIO interface till Axi Ethernet Reset is completed.
         * When we do an Axi Ethernet reset, it resets the complete core
         * including the MDIO. So if MDIO is not disabled when the reset
         * process is started, MDIO will be broken afterwards.
         */
        axienet_iow(lp, XAE_MDIO_MC_OFFSET, (mdio_mcreg &
                    ~XAE_MDIO_MC_MDIOEN_MASK));

        __axienet_device_reset(lp, XAXIDMA_TX_CR_OFFSET);
        __axienet_device_reset(lp, XAXIDMA_RX_CR_OFFSET);

        axienet_iow(lp, XAE_MDIO_MC_OFFSET, mdio_mcreg);
        axienet_mdio_wait_until_ready(lp);

        for (i = 0; i < TX_BD_NUM; i++) {
                cur_p = &lp->tx_bd_v[i];
                if (cur_p->phys)
                        dma_unmap_single(ndev->dev.parent, cur_p->phys,
                                         (cur_p->cntrl &
                                          XAXIDMA_BD_CTRL_LENGTH_MASK),
                                         DMA_TO_DEVICE);
                if (cur_p->app4)
                        dev_kfree_skb_irq((struct sk_buff *) cur_p->app4);
                cur_p->phys = 0;
                cur_p->cntrl = 0;
                cur_p->status = 0;
                cur_p->app0 = 0;
                cur_p->app1 = 0;
                cur_p->app2 = 0;
                cur_p->app3 = 0;
                cur_p->app4 = 0;
                cur_p->sw_id_offset = 0;
        }

        for (i = 0; i < RX_BD_NUM; i++) {
                cur_p = &lp->rx_bd_v[i];
                cur_p->status = 0;
                cur_p->app0 = 0;
                cur_p->app1 = 0;
                cur_p->app2 = 0;
                cur_p->app3 = 0;
                cur_p->app4 = 0;
        }

        lp->tx_bd_ci = 0;
        lp->tx_bd_tail = 0;
        lp->rx_bd_ci = 0;

        /* Start updating the Rx channel control register */
        cr = axienet_dma_in32(lp, XAXIDMA_RX_CR_OFFSET);
        /* Update the interrupt coalesce count */
        cr = ((cr & ~XAXIDMA_COALESCE_MASK) |
              (XAXIDMA_DFT_RX_THRESHOLD << XAXIDMA_COALESCE_SHIFT));
        /* Update the delay timer count */
        cr = ((cr & ~XAXIDMA_DELAY_MASK) |
              (XAXIDMA_DFT_RX_WAITBOUND << XAXIDMA_DELAY_SHIFT));
        /* Enable coalesce, delay timer and error interrupts */
        cr |= XAXIDMA_IRQ_ALL_MASK;
        /* Finally write to the Rx channel control register */
        axienet_dma_out32(lp, XAXIDMA_RX_CR_OFFSET, cr);

        /* Start updating the Tx channel control register */
        cr = axienet_dma_in32(lp, XAXIDMA_TX_CR_OFFSET);
        /* Update the interrupt coalesce count */
        cr = (((cr & ~XAXIDMA_COALESCE_MASK)) |
              (XAXIDMA_DFT_TX_THRESHOLD << XAXIDMA_COALESCE_SHIFT));
        /* Update the delay timer count */
        cr = (((cr & ~XAXIDMA_DELAY_MASK)) |
              (XAXIDMA_DFT_TX_WAITBOUND << XAXIDMA_DELAY_SHIFT));
        /* Enable coalesce, delay timer and error interrupts */
        cr |= XAXIDMA_IRQ_ALL_MASK;
        /* Finally write to the Tx channel control register */
        axienet_dma_out32(lp, XAXIDMA_TX_CR_OFFSET, cr);

        /* Populate the tail pointer and bring the Rx Axi DMA engine out of
         * halted state. This will make the Rx side ready for reception.
         */
        axienet_dma_out32(lp, XAXIDMA_RX_CDESC_OFFSET, lp->rx_bd_p);
        cr = axienet_dma_in32(lp, XAXIDMA_RX_CR_OFFSET);
        axienet_dma_out32(lp, XAXIDMA_RX_CR_OFFSET,
                          cr | XAXIDMA_CR_RUNSTOP_MASK);
        axienet_dma_out32(lp, XAXIDMA_RX_TDESC_OFFSET, lp->rx_bd_p +
                          (sizeof(*lp->rx_bd_v) * (RX_BD_NUM - 1)));

        /* Write to the RS (Run-stop) bit in the Tx channel control register.
         * Tx channel is now ready to run. But only after we write to the
         * tail pointer register that the Tx channel will start transmitting
         */
        axienet_dma_out32(lp, XAXIDMA_TX_CDESC_OFFSET, lp->tx_bd_p);
        cr = axienet_dma_in32(lp, XAXIDMA_TX_CR_OFFSET);
        axienet_dma_out32(lp, XAXIDMA_TX_CR_OFFSET,
                          cr | XAXIDMA_CR_RUNSTOP_MASK);

        axienet_status = axienet_ior(lp, XAE_RCW1_OFFSET);
        axienet_status &= ~XAE_RCW1_RX_MASK;
        axienet_iow(lp, XAE_RCW1_OFFSET, axienet_status);

        axienet_status = axienet_ior(lp, XAE_IP_OFFSET);
        if (axienet_status & XAE_INT_RXRJECT_MASK)
                axienet_iow(lp, XAE_IS_OFFSET, XAE_INT_RXRJECT_MASK);
        axienet_iow(lp, XAE_FCC_OFFSET, XAE_FCC_FCRX_MASK);

        /* Sync default options with HW but leave receiver and
         * transmitter disabled.
         */
        axienet_setoptions(ndev, lp->options &
                           ~(XAE_OPTION_TXEN | XAE_OPTION_RXEN));
        axienet_set_mac_address(ndev, NULL);
        axienet_set_multicast_list(ndev);
        axienet_setoptions(ndev, lp->options);
}

/**
 * axienet_probe - Axi Ethernet probe function.
 * @pdev:       Pointer to platform device structure.
 *
 * Return: 0, on success
 *          Non-zero error value on failure.
 *
 * This is the probe routine for Axi Ethernet driver. This is called before
 * any other driver routines are invoked. It allocates and sets up the Ethernet
 * device. Parses through device tree and populates fields of
 * axienet_local. It registers the Ethernet device.
 */
static int axienet_probe(struct platform_device *pdev)
{
        int ret;
        struct device_node *np;
        struct axienet_local *lp;
        struct net_device *ndev;
        const void *mac_addr;
        struct resource *ethres, dmares;
        u32 value;

        ndev = alloc_etherdev(sizeof(*lp));
        if (!ndev)
                return -ENOMEM;

        platform_set_drvdata(pdev, ndev);

        SET_NETDEV_DEV(ndev, &pdev->dev);
        ndev->flags &= ~IFF_MULTICAST;  /* clear multicast */
        ndev->features = NETIF_F_SG;
        ndev->netdev_ops = &axienet_netdev_ops;
        ndev->ethtool_ops = &axienet_ethtool_ops;

        /* MTU range: 64 - 9000 */
        ndev->min_mtu = 64;
        ndev->max_mtu = XAE_JUMBO_MTU;

        lp = netdev_priv(ndev);
        lp->ndev = ndev;
        lp->dev = &pdev->dev;
        lp->options = XAE_OPTION_DEFAULTS;
        /* Map device registers */
        ethres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        lp->regs = devm_ioremap_resource(&pdev->dev, ethres);
        if (IS_ERR(lp->regs)) {
                dev_err(&pdev->dev, "could not map Axi Ethernet regs.\n");
                ret = PTR_ERR(lp->regs);
                goto free_netdev;
        }

        /* Setup checksum offload, but default to off if not specified */
        lp->features = 0;

        ret = of_property_read_u32(pdev->dev.of_node, "xlnx,txcsum", &value);
        if (!ret) {
                switch (value) {
                case 1:
                        lp->csum_offload_on_tx_path =
                                XAE_FEATURE_PARTIAL_TX_CSUM;
                        lp->features |= XAE_FEATURE_PARTIAL_TX_CSUM;
                        /* Can checksum TCP/UDP over IPv4. */
                        ndev->features |= NETIF_F_IP_CSUM;
                        break;
                case 2:
                        lp->csum_offload_on_tx_path =
                                XAE_FEATURE_FULL_TX_CSUM;
                        lp->features |= XAE_FEATURE_FULL_TX_CSUM;
                        /* Can checksum TCP/UDP over IPv4. */
                        ndev->features |= NETIF_F_IP_CSUM;
                        break;
                default:
                        lp->csum_offload_on_tx_path = XAE_NO_CSUM_OFFLOAD;
                }
        }
        ret = of_property_read_u32(pdev->dev.of_node, "xlnx,rxcsum", &value);
        if (!ret) {
                switch (value) {
                case 1:
                        lp->csum_offload_on_rx_path =
                                XAE_FEATURE_PARTIAL_RX_CSUM;
                        lp->features |= XAE_FEATURE_PARTIAL_RX_CSUM;
                        break;
                case 2:
                        lp->csum_offload_on_rx_path =
                                XAE_FEATURE_FULL_RX_CSUM;
                        lp->features |= XAE_FEATURE_FULL_RX_CSUM;
                        break;
                default:
                        lp->csum_offload_on_rx_path = XAE_NO_CSUM_OFFLOAD;
                }
        }
        /* For supporting jumbo frames, the Axi Ethernet hardware must have
         * a larger Rx/Tx Memory. Typically, the size must be large so that
         * we can enable jumbo option and start supporting jumbo frames.
         * Here we check for memory allocated for Rx/Tx in the hardware from
         * the device-tree and accordingly set flags.
         */
        of_property_read_u32(pdev->dev.of_node, "xlnx,rxmem", &lp->rxmem);
        of_property_read_u32(pdev->dev.of_node, "xlnx,phy-type", &lp->phy_type);

        /* Find the DMA node, map the DMA registers, and decode the DMA IRQs */
        np = of_parse_phandle(pdev->dev.of_node, "axistream-connected", 0);
        if (!np) {
                dev_err(&pdev->dev, "could not find DMA node\n");
                ret = -ENODEV;
                goto free_netdev;
        }
        ret = of_address_to_resource(np, 0, &dmares);
        if (ret) {
                dev_err(&pdev->dev, "unable to get DMA resource\n");
                goto free_netdev;
        }
        lp->dma_regs = devm_ioremap_resource(&pdev->dev, &dmares);
        if (IS_ERR(lp->dma_regs)) {
                dev_err(&pdev->dev, "could not map DMA regs\n");
                ret = PTR_ERR(lp->dma_regs);
                goto free_netdev;
        }
        lp->rx_irq = irq_of_parse_and_map(np, 1);
        lp->tx_irq = irq_of_parse_and_map(np, 0);
        of_node_put(np);
        if ((lp->rx_irq <= 0) || (lp->tx_irq <= 0)) {
                dev_err(&pdev->dev, "could not determine irqs\n");
                ret = -ENOMEM;
                goto free_netdev;
        }

        /* Retrieve the MAC address */
        mac_addr = of_get_mac_address(pdev->dev.of_node);
        if (!mac_addr) {
                dev_err(&pdev->dev, "could not find MAC address\n");
                goto free_netdev;
        }
        axienet_set_mac_address(ndev, mac_addr);

        lp->coalesce_count_rx = XAXIDMA_DFT_RX_THRESHOLD;
        lp->coalesce_count_tx = XAXIDMA_DFT_TX_THRESHOLD;

        lp->phy_node = of_parse_phandle(pdev->dev.of_node, "phy-handle", 0);
        if (lp->phy_node) {
                ret = axienet_mdio_setup(lp, pdev->dev.of_node);
                if (ret)
                        dev_warn(&pdev->dev, "error registering MDIO bus\n");
        }

        ret = register_netdev(lp->ndev);
        if (ret) {
                dev_err(lp->dev, "register_netdev() error (%i)\n", ret);
                goto free_netdev;
        }

        return 0;

free_netdev:
        free_netdev(ndev);

        return ret;
}

static int axienet_remove(struct platform_device *pdev)
{
        struct net_device *ndev = platform_get_drvdata(pdev);
        struct axienet_local *lp = netdev_priv(ndev);

        axienet_mdio_teardown(lp);
        unregister_netdev(ndev);

        of_node_put(lp->phy_node);
        lp->phy_node = NULL;

        free_netdev(ndev);

        return 0;
}

static struct platform_driver axienet_driver = {
        .probe = axienet_probe,
        .remove = axienet_remove,
        .driver = {
                 .name = "xilinx_axienet",
                 .of_match_table = axienet_of_match,
        },
};

module_platform_driver(axienet_driver);

MODULE_DESCRIPTION("Xilinx Axi Ethernet driver");
MODULE_AUTHOR("Xilinx");
MODULE_LICENSE("GPL");