/*
 * Driver for Xilinx TEMAC Ethernet device
 *
 * 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.
 *
 * This is a driver for the Xilinx ll_temac ipcore which is often used
 * in the Virtex and Spartan series of chips.
 *
 * Notes:
 * - The ll_temac hardware uses indirect access for many of the TEMAC
 *   registers, include the MDIO bus.  However, indirect access to MDIO
 *   registers take considerably more clock cycles than to TEMAC registers.
 *   MDIO accesses are long, so threads doing them should probably sleep
 *   rather than busywait.  However, since only one indirect access can be
 *   in progress at any given time, that means that *all* indirect accesses
 *   could end up sleeping (to wait for an MDIO access to complete).
 *   Fortunately none of the indirect accesses are on the 'hot' path for tx
 *   or rx, so this should be okay.
 *
 * TODO:
 * - Factor out locallink DMA code into separate driver
 * - Fix multicast assignment.
 * - Fix support for hardware checksumming.
 * - Testing.  Lots and lots of testing.
 *
 */

#include <linux/delay.h>
#include <linux/etherdevice.h>
#include <linux/mii.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/netdevice.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/of_mdio.h>
#include <linux/of_platform.h>
#include <linux/of_address.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/tcp.h>      /* needed for sizeof(tcphdr) */
#include <linux/udp.h>      /* needed for sizeof(udphdr) */
#include <linux/phy.h>
#include <linux/in.h>
#include <linux/io.h>
#include <linux/ip.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/dma-mapping.h>

#include "ll_temac.h"

#define TX_BD_NUM   64
#define RX_BD_NUM   128

/* ---------------------------------------------------------------------
 * Low level register access functions
 */

u32 temac_ior(struct temac_local *lp, int offset)
{
        return in_be32((u32 *)(lp->regs + offset));
}

void temac_iow(struct temac_local *lp, int offset, u32 value)
{
        out_be32((u32 *) (lp->regs + offset), value);
}

int temac_indirect_busywait(struct temac_local *lp)
{
        unsigned long end = jiffies + 2;

        while (!(temac_ior(lp, XTE_RDY0_OFFSET) & XTE_RDY0_HARD_ACS_RDY_MASK)) {
                if (time_before_eq(end, jiffies)) {
                        WARN_ON(1);
                        return -ETIMEDOUT;
                }
                msleep(1);
        }
        return 0;
}

/**
 * temac_indirect_in32
 *
 * lp->indirect_mutex must be held when calling this function
 */
u32 temac_indirect_in32(struct temac_local *lp, int reg)
{
        u32 val;

        if (temac_indirect_busywait(lp))
                return -ETIMEDOUT;
        temac_iow(lp, XTE_CTL0_OFFSET, reg);
        if (temac_indirect_busywait(lp))
                return -ETIMEDOUT;
        val = temac_ior(lp, XTE_LSW0_OFFSET);

        return val;
}

/**
 * temac_indirect_out32
 *
 * lp->indirect_mutex must be held when calling this function
 */
void temac_indirect_out32(struct temac_local *lp, int reg, u32 value)
{
        if (temac_indirect_busywait(lp))
                return;
        temac_iow(lp, XTE_LSW0_OFFSET, value);
        temac_iow(lp, XTE_CTL0_OFFSET, CNTLREG_WRITE_ENABLE_MASK | reg);
        temac_indirect_busywait(lp);
}

/**
 * temac_dma_in32 - Memory mapped DMA read, this function expects a
 * register input that is based on DCR word addresses which
 * are then converted to memory mapped byte addresses
 */
static u32 temac_dma_in32(struct temac_local *lp, int reg)
{
        return in_be32((u32 *)(lp->sdma_regs + (reg << 2)));
}

/**
 * temac_dma_out32 - Memory mapped DMA read, this function expects a
 * register input that is based on DCR word addresses which
 * are then converted to memory mapped byte addresses
 */
static void temac_dma_out32(struct temac_local *lp, int reg, u32 value)
{
        out_be32((u32 *)(lp->sdma_regs + (reg << 2)), value);
}

/* DMA register access functions can be DCR based or memory mapped.
 * The PowerPC 440 is DCR based, the PowerPC 405 and MicroBlaze are both
 * memory mapped.
 */
#ifdef CONFIG_PPC_DCR

/**
 * temac_dma_dcr_in32 - DCR based DMA read
 */
static u32 temac_dma_dcr_in(struct temac_local *lp, int reg)
{
        return dcr_read(lp->sdma_dcrs, reg);
}

/**
 * temac_dma_dcr_out32 - DCR based DMA write
 */
static void temac_dma_dcr_out(struct temac_local *lp, int reg, u32 value)
{
        dcr_write(lp->sdma_dcrs, reg, value);
}

/**
 * temac_dcr_setup - If the DMA is DCR based, then setup the address and
 * I/O  functions
 */
static int temac_dcr_setup(struct temac_local *lp, struct platform_device *op,
                                struct device_node *np)
{
        unsigned int dcrs;

        /* setup the dcr address mapping if it's in the device tree */

        dcrs = dcr_resource_start(np, 0);
        if (dcrs != 0) {
                lp->sdma_dcrs = dcr_map(np, dcrs, dcr_resource_len(np, 0));
                lp->dma_in = temac_dma_dcr_in;
                lp->dma_out = temac_dma_dcr_out;
                dev_dbg(&op->dev, "DCR base: %x\n", dcrs);
                return 0;
        }
        /* no DCR in the device tree, indicate a failure */
        return -1;
}

#else

/*
 * temac_dcr_setup - This is a stub for when DCR is not supported,
 * such as with MicroBlaze
 */
static int temac_dcr_setup(struct temac_local *lp, struct platform_device *op,
                                struct device_node *np)
{
        return -1;
}

#endif

/**
 * temac_dma_bd_release - Release buffer descriptor rings
 */
static void temac_dma_bd_release(struct net_device *ndev)
{
        struct temac_local *lp = netdev_priv(ndev);
        int i;

        /* Reset Local Link (DMA) */
        lp->dma_out(lp, DMA_CONTROL_REG, DMA_CONTROL_RST);

        for (i = 0; i < RX_BD_NUM; i++) {
                if (!lp->rx_skb[i])
                        break;
                else {
                        dma_unmap_single(ndev->dev.parent, lp->rx_bd_v[i].phys,
                                        XTE_MAX_JUMBO_FRAME_SIZE, DMA_FROM_DEVICE);
                        dev_kfree_skb(lp->rx_skb[i]);
                }
        }
        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);
        kfree(lp->rx_skb);
}

/**
 * temac_dma_bd_init - Setup buffer descriptor rings
 */
static int temac_dma_bd_init(struct net_device *ndev)
{
        struct temac_local *lp = netdev_priv(ndev);
        struct sk_buff *skb;
        int i;

        lp->rx_skb = kcalloc(RX_BD_NUM, sizeof(*lp->rx_skb), GFP_KERNEL);
        if (!lp->rx_skb)
                goto out;

        /* allocate the tx and rx ring buffer descriptors. */
        /* returns a virtual address and a physical address. */
        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,
                                                XTE_MAX_JUMBO_FRAME_SIZE);
                if (!skb)
                        goto out;

                lp->rx_skb[i] = skb;
                /* returns physical address of skb->data */
                lp->rx_bd_v[i].phys = dma_map_single(ndev->dev.parent,
                                                     skb->data,
                                                     XTE_MAX_JUMBO_FRAME_SIZE,
                                                     DMA_FROM_DEVICE);
                lp->rx_bd_v[i].len = XTE_MAX_JUMBO_FRAME_SIZE;
                lp->rx_bd_v[i].app0 = STS_CTRL_APP0_IRQONEND;
        }

        lp->dma_out(lp, TX_CHNL_CTRL, 0x10220400 |
                                          CHNL_CTRL_IRQ_EN |
                                          CHNL_CTRL_IRQ_DLY_EN |
                                          CHNL_CTRL_IRQ_COAL_EN);
        /* 0x10220483 */
        /* 0x00100483 */
        lp->dma_out(lp, RX_CHNL_CTRL, 0xff070000 |
                                          CHNL_CTRL_IRQ_EN |
                                          CHNL_CTRL_IRQ_DLY_EN |
                                          CHNL_CTRL_IRQ_COAL_EN |
                                          CHNL_CTRL_IRQ_IOE);
        /* 0xff010283 */

        lp->dma_out(lp, RX_CURDESC_PTR,  lp->rx_bd_p);
        lp->dma_out(lp, RX_TAILDESC_PTR,
                       lp->rx_bd_p + (sizeof(*lp->rx_bd_v) * (RX_BD_NUM - 1)));
        lp->dma_out(lp, TX_CURDESC_PTR, lp->tx_bd_p);

        /* Init descriptor indexes */
        lp->tx_bd_ci = 0;
        lp->tx_bd_next = 0;
        lp->tx_bd_tail = 0;
        lp->rx_bd_ci = 0;

        return 0;

out:
        temac_dma_bd_release(ndev);
        return -ENOMEM;
}

/* ---------------------------------------------------------------------
 * net_device_ops
 */

static void temac_do_set_mac_address(struct net_device *ndev)
{
        struct temac_local *lp = netdev_priv(ndev);

        /* set up unicast MAC address filter set its mac address */
        mutex_lock(&lp->indirect_mutex);
        temac_indirect_out32(lp, XTE_UAW0_OFFSET,
                             (ndev->dev_addr[0]) |
                             (ndev->dev_addr[1] << 8) |
                             (ndev->dev_addr[2] << 16) |
                             (ndev->dev_addr[3] << 24));
        /* There are reserved bits in EUAW1
         * so don't affect them Set MAC bits [47:32] in EUAW1 */
        temac_indirect_out32(lp, XTE_UAW1_OFFSET,
                             (ndev->dev_addr[4] & 0x000000ff) |
                             (ndev->dev_addr[5] << 8));
        mutex_unlock(&lp->indirect_mutex);
}

static int temac_init_mac_address(struct net_device *ndev, void *address)
{
        memcpy(ndev->dev_addr, address, ETH_ALEN);
        if (!is_valid_ether_addr(ndev->dev_addr))
                eth_hw_addr_random(ndev);
        temac_do_set_mac_address(ndev);
        return 0;
}

static int temac_set_mac_address(struct net_device *ndev, void *p)
{
        struct sockaddr *addr = p;

        if (!is_valid_ether_addr(addr->sa_data))
                return -EADDRNOTAVAIL;
        memcpy(ndev->dev_addr, addr->sa_data, ETH_ALEN);
        temac_do_set_mac_address(ndev);
        return 0;
}

static void temac_set_multicast_list(struct net_device *ndev)
{
        struct temac_local *lp = netdev_priv(ndev);
        u32 multi_addr_msw, multi_addr_lsw, val;
        int i;

        mutex_lock(&lp->indirect_mutex);
        if (ndev->flags & (IFF_ALLMULTI | IFF_PROMISC) ||
            netdev_mc_count(ndev) > MULTICAST_CAM_TABLE_NUM) {
                /*
                 *      We must make the kernel realise we had to move
                 *      into promisc mode or we start all out war on
                 *      the cable. If it was a promisc request the
                 *      flag is already set. If not we assert it.
                 */
                ndev->flags |= IFF_PROMISC;
                temac_indirect_out32(lp, XTE_AFM_OFFSET, XTE_AFM_EPPRM_MASK);
                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 >= MULTICAST_CAM_TABLE_NUM)
                                break;
                        multi_addr_msw = ((ha->addr[3] << 24) |
                                          (ha->addr[2] << 16) |
                                          (ha->addr[1] << 8) |
                                          (ha->addr[0]));
                        temac_indirect_out32(lp, XTE_MAW0_OFFSET,
                                             multi_addr_msw);
                        multi_addr_lsw = ((ha->addr[5] << 8) |
                                          (ha->addr[4]) | (i << 16));
                        temac_indirect_out32(lp, XTE_MAW1_OFFSET,
                                             multi_addr_lsw);
                        i++;
                }
        } else {
                val = temac_indirect_in32(lp, XTE_AFM_OFFSET);
                temac_indirect_out32(lp, XTE_AFM_OFFSET,
                                     val & ~XTE_AFM_EPPRM_MASK);
                temac_indirect_out32(lp, XTE_MAW0_OFFSET, 0);
                temac_indirect_out32(lp, XTE_MAW1_OFFSET, 0);
                dev_info(&ndev->dev, "Promiscuous mode disabled.\n");
        }
        mutex_unlock(&lp->indirect_mutex);
}

struct temac_option {
        int flg;
        u32 opt;
        u32 reg;
        u32 m_or;
        u32 m_and;
} temac_options[] = {
        /* Turn on jumbo packet support for both Rx and Tx */
        {
                .opt = XTE_OPTION_JUMBO,
                .reg = XTE_TXC_OFFSET,
                .m_or = XTE_TXC_TXJMBO_MASK,
        },
        {
                .opt = XTE_OPTION_JUMBO,
                .reg = XTE_RXC1_OFFSET,
                .m_or =XTE_RXC1_RXJMBO_MASK,
        },
        /* Turn on VLAN packet support for both Rx and Tx */
        {
                .opt = XTE_OPTION_VLAN,
                .reg = XTE_TXC_OFFSET,
                .m_or =XTE_TXC_TXVLAN_MASK,
        },
        {
                .opt = XTE_OPTION_VLAN,
                .reg = XTE_RXC1_OFFSET,
                .m_or =XTE_RXC1_RXVLAN_MASK,
        },
        /* Turn on FCS stripping on receive packets */
        {
                .opt = XTE_OPTION_FCS_STRIP,
                .reg = XTE_RXC1_OFFSET,
                .m_or =XTE_RXC1_RXFCS_MASK,
        },
        /* Turn on FCS insertion on transmit packets */
        {
                .opt = XTE_OPTION_FCS_INSERT,
                .reg = XTE_TXC_OFFSET,
                .m_or =XTE_TXC_TXFCS_MASK,
        },
        /* Turn on length/type field checking on receive packets */
        {
                .opt = XTE_OPTION_LENTYPE_ERR,
                .reg = XTE_RXC1_OFFSET,
                .m_or =XTE_RXC1_RXLT_MASK,
        },
        /* Turn on flow control */
        {
                .opt = XTE_OPTION_FLOW_CONTROL,
                .reg = XTE_FCC_OFFSET,
                .m_or =XTE_FCC_RXFLO_MASK,
        },
        /* Turn on flow control */
        {
                .opt = XTE_OPTION_FLOW_CONTROL,
                .reg = XTE_FCC_OFFSET,
                .m_or =XTE_FCC_TXFLO_MASK,
        },
        /* Turn on promiscuous frame filtering (all frames are received ) */
        {
                .opt = XTE_OPTION_PROMISC,
                .reg = XTE_AFM_OFFSET,
                .m_or =XTE_AFM_EPPRM_MASK,
        },
        /* Enable transmitter if not already enabled */
        {
                .opt = XTE_OPTION_TXEN,
                .reg = XTE_TXC_OFFSET,
                .m_or =XTE_TXC_TXEN_MASK,
        },
        /* Enable receiver? */
        {
                .opt = XTE_OPTION_RXEN,
                .reg = XTE_RXC1_OFFSET,
                .m_or =XTE_RXC1_RXEN_MASK,
        },
        {}
};

/**
 * temac_setoptions
 */
static u32 temac_setoptions(struct net_device *ndev, u32 options)
{
        struct temac_local *lp = netdev_priv(ndev);
        struct temac_option *tp = &temac_options[0];
        int reg;

        mutex_lock(&lp->indirect_mutex);
        while (tp->opt) {
                reg = temac_indirect_in32(lp, tp->reg) & ~tp->m_or;
                if (options & tp->opt)
                        reg |= tp->m_or;
                temac_indirect_out32(lp, tp->reg, reg);
                tp++;
        }
        lp->options |= options;
        mutex_unlock(&lp->indirect_mutex);

        return 0;
}

/* Initialize temac */
static void temac_device_reset(struct net_device *ndev)
{
        struct temac_local *lp = netdev_priv(ndev);
        u32 timeout;
        u32 val;

        /* Perform a software reset */

        /* 0x300 host enable bit ? */
        /* reset PHY through control register ?:1 */

        dev_dbg(&ndev->dev, "%s()\n", __func__);

        mutex_lock(&lp->indirect_mutex);
        /* Reset the receiver and wait for it to finish reset */
        temac_indirect_out32(lp, XTE_RXC1_OFFSET, XTE_RXC1_RXRST_MASK);
        timeout = 1000;
        while (temac_indirect_in32(lp, XTE_RXC1_OFFSET) & XTE_RXC1_RXRST_MASK) {
                udelay(1);
                if (--timeout == 0) {
                        dev_err(&ndev->dev,
                                "temac_device_reset RX reset timeout!!\n");
                        break;
                }
        }

        /* Reset the transmitter and wait for it to finish reset */
        temac_indirect_out32(lp, XTE_TXC_OFFSET, XTE_TXC_TXRST_MASK);
        timeout = 1000;
        while (temac_indirect_in32(lp, XTE_TXC_OFFSET) & XTE_TXC_TXRST_MASK) {
                udelay(1);
                if (--timeout == 0) {
                        dev_err(&ndev->dev,
                                "temac_device_reset TX reset timeout!!\n");
                        break;
                }
        }

        /* Disable the receiver */
        val = temac_indirect_in32(lp, XTE_RXC1_OFFSET);
        temac_indirect_out32(lp, XTE_RXC1_OFFSET, val & ~XTE_RXC1_RXEN_MASK);

        /* Reset Local Link (DMA) */
        lp->dma_out(lp, DMA_CONTROL_REG, DMA_CONTROL_RST);
        timeout = 1000;
        while (lp->dma_in(lp, DMA_CONTROL_REG) & DMA_CONTROL_RST) {
                udelay(1);
                if (--timeout == 0) {
                        dev_err(&ndev->dev,
                                "temac_device_reset DMA reset timeout!!\n");
                        break;
                }
        }
        lp->dma_out(lp, DMA_CONTROL_REG, DMA_TAIL_ENABLE);

        if (temac_dma_bd_init(ndev)) {
                dev_err(&ndev->dev,
                                "temac_device_reset descriptor allocation failed\n");
        }

        temac_indirect_out32(lp, XTE_RXC0_OFFSET, 0);
        temac_indirect_out32(lp, XTE_RXC1_OFFSET, 0);
        temac_indirect_out32(lp, XTE_TXC_OFFSET, 0);
        temac_indirect_out32(lp, XTE_FCC_OFFSET, XTE_FCC_RXFLO_MASK);

        mutex_unlock(&lp->indirect_mutex);

        /* Sync default options with HW
         * but leave receiver and transmitter disabled.  */
        temac_setoptions(ndev,
                         lp->options & ~(XTE_OPTION_TXEN | XTE_OPTION_RXEN));

        temac_do_set_mac_address(ndev);

        /* Set address filter table */
        temac_set_multicast_list(ndev);
        if (temac_setoptions(ndev, lp->options))
                dev_err(&ndev->dev, "Error setting TEMAC options\n");

        /* Init Driver variable */
        ndev->trans_start = jiffies; /* prevent tx timeout */
}

void temac_adjust_link(struct net_device *ndev)
{
        struct temac_local *lp = netdev_priv(ndev);
        struct phy_device *phy = lp->phy_dev;
        u32 mii_speed;
        int link_state;

        /* hash together the state values to decide if something has changed */
        link_state = phy->speed | (phy->duplex << 1) | phy->link;

        mutex_lock(&lp->indirect_mutex);
        if (lp->last_link != link_state) {
                mii_speed = temac_indirect_in32(lp, XTE_EMCFG_OFFSET);
                mii_speed &= ~XTE_EMCFG_LINKSPD_MASK;

                switch (phy->speed) {
                case SPEED_1000: mii_speed |= XTE_EMCFG_LINKSPD_1000; break;
                case SPEED_100: mii_speed |= XTE_EMCFG_LINKSPD_100; break;
                case SPEED_10: mii_speed |= XTE_EMCFG_LINKSPD_10; break;
                }

                /* Write new speed setting out to TEMAC */
                temac_indirect_out32(lp, XTE_EMCFG_OFFSET, mii_speed);
                lp->last_link = link_state;
                phy_print_status(phy);
        }
        mutex_unlock(&lp->indirect_mutex);
}

static void temac_start_xmit_done(struct net_device *ndev)
{
        struct temac_local *lp = netdev_priv(ndev);
        struct cdmac_bd *cur_p;
        unsigned int stat = 0;

        cur_p = &lp->tx_bd_v[lp->tx_bd_ci];
        stat = cur_p->app0;

        while (stat & STS_CTRL_APP0_CMPLT) {
                dma_unmap_single(ndev->dev.parent, cur_p->phys, cur_p->len,
                                 DMA_TO_DEVICE);
                if (cur_p->app4)
                        dev_kfree_skb_irq((struct sk_buff *)cur_p->app4);
                cur_p->app0 = 0;
                cur_p->app1 = 0;
                cur_p->app2 = 0;
                cur_p->app3 = 0;
                cur_p->app4 = 0;

                ndev->stats.tx_packets++;
                ndev->stats.tx_bytes += cur_p->len;

                lp->tx_bd_ci++;
                if (lp->tx_bd_ci >= TX_BD_NUM)
                        lp->tx_bd_ci = 0;

                cur_p = &lp->tx_bd_v[lp->tx_bd_ci];
                stat = cur_p->app0;
        }

        netif_wake_queue(ndev);
}

static inline int temac_check_tx_bd_space(struct temac_local *lp, int num_frag)
{
        struct cdmac_bd *cur_p;
        int tail;

        tail = lp->tx_bd_tail;
        cur_p = &lp->tx_bd_v[tail];

        do {
                if (cur_p->app0)
                        return NETDEV_TX_BUSY;

                tail++;
                if (tail >= TX_BD_NUM)
                        tail = 0;

                cur_p = &lp->tx_bd_v[tail];
                num_frag--;
        } while (num_frag >= 0);

        return 0;
}

static int temac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
{
        struct temac_local *lp = netdev_priv(ndev);
        struct cdmac_bd *cur_p;
        dma_addr_t start_p, tail_p;
        int ii;
        unsigned long num_frag;
        skb_frag_t *frag;

        num_frag = skb_shinfo(skb)->nr_frags;
        frag = &skb_shinfo(skb)->frags[0];
        start_p = lp->tx_bd_p + sizeof(*lp->tx_bd_v) * lp->tx_bd_tail;
        cur_p = &lp->tx_bd_v[lp->tx_bd_tail];

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

        cur_p->app0 = 0;
        if (skb->ip_summed == CHECKSUM_PARTIAL) {
                unsigned int csum_start_off = skb_checksum_start_offset(skb);
                unsigned int csum_index_off = csum_start_off + skb->csum_offset;

                cur_p->app0 |= 1; /* TX Checksum Enabled */
                cur_p->app1 = (csum_start_off << 16) | csum_index_off;
                cur_p->app2 = 0;  /* initial checksum seed */
        }

        cur_p->app0 |= STS_CTRL_APP0_SOP;
        cur_p->len = skb_headlen(skb);
        cur_p->phys = dma_map_single(ndev->dev.parent, skb->data, skb->len,
                                     DMA_TO_DEVICE);
        cur_p->app4 = (unsigned long)skb;

        for (ii = 0; ii < num_frag; ii++) {
                lp->tx_bd_tail++;
                if (lp->tx_bd_tail >= TX_BD_NUM)
                        lp->tx_bd_tail = 0;

                cur_p = &lp->tx_bd_v[lp->tx_bd_tail];
                cur_p->phys = dma_map_single(ndev->dev.parent,
                                             skb_frag_address(frag),
                                             skb_frag_size(frag), DMA_TO_DEVICE);
                cur_p->len = skb_frag_size(frag);
                cur_p->app0 = 0;
                frag++;
        }
        cur_p->app0 |= STS_CTRL_APP0_EOP;

        tail_p = lp->tx_bd_p + sizeof(*lp->tx_bd_v) * lp->tx_bd_tail;
        lp->tx_bd_tail++;
        if (lp->tx_bd_tail >= TX_BD_NUM)
                lp->tx_bd_tail = 0;

        skb_tx_timestamp(skb);

        /* Kick off the transfer */
        lp->dma_out(lp, TX_TAILDESC_PTR, tail_p); /* DMA start */

        return NETDEV_TX_OK;
}


static void ll_temac_recv(struct net_device *ndev)
{
        struct temac_local *lp = netdev_priv(ndev);
        struct sk_buff *skb, *new_skb;
        unsigned int bdstat;
        struct cdmac_bd *cur_p;
        dma_addr_t tail_p;
        int length;
        unsigned long flags;

        spin_lock_irqsave(&lp->rx_lock, flags);

        tail_p = lp->rx_bd_p + sizeof(*lp->rx_bd_v) * lp->rx_bd_ci;
        cur_p = &lp->rx_bd_v[lp->rx_bd_ci];

        bdstat = cur_p->app0;
        while ((bdstat & STS_CTRL_APP0_CMPLT)) {

                skb = lp->rx_skb[lp->rx_bd_ci];
                length = cur_p->app4 & 0x3FFF;

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

                skb_put(skb, length);
                skb->protocol = eth_type_trans(skb, ndev);
                skb_checksum_none_assert(skb);

                /* if we're doing rx csum offload, set it up */
                if (((lp->temac_features & TEMAC_FEATURE_RX_CSUM) != 0) &&
                    (skb->protocol == htons(ETH_P_IP)) &&
                    (skb->len > 64)) {

                        skb->csum = cur_p->app3 & 0xFFFF;
                        skb->ip_summed = CHECKSUM_COMPLETE;
                }

                if (!skb_defer_rx_timestamp(skb))
                        netif_rx(skb);

                ndev->stats.rx_packets++;
                ndev->stats.rx_bytes += length;

                new_skb = netdev_alloc_skb_ip_align(ndev,
                                                XTE_MAX_JUMBO_FRAME_SIZE);
                if (!new_skb) {
                        spin_unlock_irqrestore(&lp->rx_lock, flags);
                        return;
                }

                cur_p->app0 = STS_CTRL_APP0_IRQONEND;
                cur_p->phys = dma_map_single(ndev->dev.parent, new_skb->data,
                                             XTE_MAX_JUMBO_FRAME_SIZE,
                                             DMA_FROM_DEVICE);
                cur_p->len = XTE_MAX_JUMBO_FRAME_SIZE;
                lp->rx_skb[lp->rx_bd_ci] = new_skb;

                lp->rx_bd_ci++;
                if (lp->rx_bd_ci >= RX_BD_NUM)
                        lp->rx_bd_ci = 0;

                cur_p = &lp->rx_bd_v[lp->rx_bd_ci];
                bdstat = cur_p->app0;
        }
        lp->dma_out(lp, RX_TAILDESC_PTR, tail_p);

        spin_unlock_irqrestore(&lp->rx_lock, flags);
}

static irqreturn_t ll_temac_tx_irq(int irq, void *_ndev)
{
        struct net_device *ndev = _ndev;
        struct temac_local *lp = netdev_priv(ndev);
        unsigned int status;

        status = lp->dma_in(lp, TX_IRQ_REG);
        lp->dma_out(lp, TX_IRQ_REG, status);

        if (status & (IRQ_COAL | IRQ_DLY))
                temac_start_xmit_done(lp->ndev);
        if (status & 0x080)
                dev_err(&ndev->dev, "DMA error 0x%x\n", status);

        return IRQ_HANDLED;
}

static irqreturn_t ll_temac_rx_irq(int irq, void *_ndev)
{
        struct net_device *ndev = _ndev;
        struct temac_local *lp = netdev_priv(ndev);
        unsigned int status;

        /* Read and clear the status registers */
        status = lp->dma_in(lp, RX_IRQ_REG);
        lp->dma_out(lp, RX_IRQ_REG, status);

        if (status & (IRQ_COAL | IRQ_DLY))
                ll_temac_recv(lp->ndev);

        return IRQ_HANDLED;
}

static int temac_open(struct net_device *ndev)
{
        struct temac_local *lp = netdev_priv(ndev);
        int rc;

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

        if (lp->phy_node) {
                lp->phy_dev = of_phy_connect(lp->ndev, lp->phy_node,
                                             temac_adjust_link, 0, 0);
                if (!lp->phy_dev) {
                        dev_err(lp->dev, "of_phy_connect() failed\n");
                        return -ENODEV;
                }

                phy_start(lp->phy_dev);
        }

        temac_device_reset(ndev);

        rc = request_irq(lp->tx_irq, ll_temac_tx_irq, 0, ndev->name, ndev);
        if (rc)
                goto err_tx_irq;
        rc = request_irq(lp->rx_irq, ll_temac_rx_irq, 0, ndev->name, ndev);
        if (rc)
                goto err_rx_irq;

        return 0;

 err_rx_irq:
        free_irq(lp->tx_irq, ndev);
 err_tx_irq:
        if (lp->phy_dev)
                phy_disconnect(lp->phy_dev);
        lp->phy_dev = NULL;
        dev_err(lp->dev, "request_irq() failed\n");
        return rc;
}

static int temac_stop(struct net_device *ndev)
{
        struct temac_local *lp = netdev_priv(ndev);

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

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

        if (lp->phy_dev)
                phy_disconnect(lp->phy_dev);
        lp->phy_dev = NULL;

        temac_dma_bd_release(ndev);

        return 0;
}

#ifdef CONFIG_NET_POLL_CONTROLLER
static void
temac_poll_controller(struct net_device *ndev)
{
        struct temac_local *lp = netdev_priv(ndev);

        disable_irq(lp->tx_irq);
        disable_irq(lp->rx_irq);

        ll_temac_rx_irq(lp->tx_irq, ndev);
        ll_temac_tx_irq(lp->rx_irq, ndev);

        enable_irq(lp->tx_irq);
        enable_irq(lp->rx_irq);
}
#endif

static int temac_ioctl(struct net_device *ndev, struct ifreq *rq, int cmd)
{
        struct temac_local *lp = netdev_priv(ndev);

        if (!netif_running(ndev))
                return -EINVAL;

        if (!lp->phy_dev)
                return -EINVAL;

        return phy_mii_ioctl(lp->phy_dev, rq, cmd);
}

static const struct net_device_ops temac_netdev_ops = {
        .ndo_open = temac_open,
        .ndo_stop = temac_stop,
        .ndo_start_xmit = temac_start_xmit,
        .ndo_set_mac_address = temac_set_mac_address,
        .ndo_validate_addr = eth_validate_addr,
        .ndo_do_ioctl = temac_ioctl,
#ifdef CONFIG_NET_POLL_CONTROLLER
        .ndo_poll_controller = temac_poll_controller,
#endif
};

/* ---------------------------------------------------------------------
 * SYSFS device attributes
 */
static ssize_t temac_show_llink_regs(struct device *dev,
                                     struct device_attribute *attr, char *buf)
{
        struct net_device *ndev = dev_get_drvdata(dev);
        struct temac_local *lp = netdev_priv(ndev);
        int i, len = 0;

        for (i = 0; i < 0x11; i++)
                len += sprintf(buf + len, "%.8x%s", lp->dma_in(lp, i),
                               (i % 8) == 7 ? "\n" : " ");
        len += sprintf(buf + len, "\n");

        return len;
}

static DEVICE_ATTR(llink_regs, 0440, temac_show_llink_regs, NULL);

static struct attribute *temac_device_attrs[] = {
        &dev_attr_llink_regs.attr,
        NULL,
};

static const struct attribute_group temac_attr_group = {
        .attrs = temac_device_attrs,
};

/* ethtool support */
static int temac_get_settings(struct net_device *ndev, struct ethtool_cmd *cmd)
{
        struct temac_local *lp = netdev_priv(ndev);
        return phy_ethtool_gset(lp->phy_dev, cmd);
}

static int temac_set_settings(struct net_device *ndev, struct ethtool_cmd *cmd)
{
        struct temac_local *lp = netdev_priv(ndev);
        return phy_ethtool_sset(lp->phy_dev, cmd);
}

static int temac_nway_reset(struct net_device *ndev)
{
        struct temac_local *lp = netdev_priv(ndev);
        return phy_start_aneg(lp->phy_dev);
}

static const struct ethtool_ops temac_ethtool_ops = {
        .get_settings = temac_get_settings,
        .set_settings = temac_set_settings,
        .nway_reset = temac_nway_reset,
        .get_link = ethtool_op_get_link,
        .get_ts_info = ethtool_op_get_ts_info,
};

static int temac_of_probe(struct platform_device *op)

{
        struct device_node *np;
        struct temac_local *lp;
        struct net_device *ndev;
        const void *addr;
        __be32 *p;
        int size, rc = 0;

        /* Init network device structure */
        ndev = alloc_etherdev(sizeof(*lp));
        if (!ndev)
                return -ENOMEM;

        platform_set_drvdata(op, ndev);
        SET_NETDEV_DEV(ndev, &op->dev);
        ndev->flags &= ~IFF_MULTICAST;  /* clear multicast */
        ndev->features = NETIF_F_SG;
        ndev->netdev_ops = &temac_netdev_ops;
        ndev->ethtool_ops = &temac_ethtool_ops;
#if 0
        ndev->features |= NETIF_F_IP_CSUM; /* Can checksum TCP/UDP over IPv4. */
        ndev->features |= NETIF_F_HW_CSUM; /* Can checksum all the packets. */
        ndev->features |= NETIF_F_IPV6_CSUM; /* Can checksum IPV6 TCP/UDP */
        ndev->features |= NETIF_F_HIGHDMA; /* Can DMA to high memory. */
        ndev->features |= NETIF_F_HW_VLAN_CTAG_TX; /* Transmit VLAN hw accel */
        ndev->features |= NETIF_F_HW_VLAN_CTAG_RX; /* Receive VLAN hw acceleration */
        ndev->features |= NETIF_F_HW_VLAN_CTAG_FILTER; /* Receive VLAN filtering */
        ndev->features |= NETIF_F_VLAN_CHALLENGED; /* cannot handle VLAN pkts */
        ndev->features |= NETIF_F_GSO; /* Enable software GSO. */
        ndev->features |= NETIF_F_MULTI_QUEUE; /* Has multiple TX/RX queues */
        ndev->features |= NETIF_F_LRO; /* large receive offload */
#endif

        /* setup temac private info structure */
        lp = netdev_priv(ndev);
        lp->ndev = ndev;
        lp->dev = &op->dev;
        lp->options = XTE_OPTION_DEFAULTS;
        spin_lock_init(&lp->rx_lock);
        mutex_init(&lp->indirect_mutex);

        /* map device registers */
        lp->regs = of_iomap(op->dev.of_node, 0);
        if (!lp->regs) {
                dev_err(&op->dev, "could not map temac regs.\n");
                rc = -ENOMEM;
                goto nodev;
        }

        /* Setup checksum offload, but default to off if not specified */
        lp->temac_features = 0;
        p = (__be32 *)of_get_property(op->dev.of_node, "xlnx,txcsum", NULL);
        if (p && be32_to_cpu(*p)) {
                lp->temac_features |= TEMAC_FEATURE_TX_CSUM;
                /* Can checksum TCP/UDP over IPv4. */
                ndev->features |= NETIF_F_IP_CSUM;
        }
        p = (__be32 *)of_get_property(op->dev.of_node, "xlnx,rxcsum", NULL);
        if (p && be32_to_cpu(*p))
                lp->temac_features |= TEMAC_FEATURE_RX_CSUM;

        /* Find the DMA node, map the DMA registers, and decode the DMA IRQs */
        np = of_parse_phandle(op->dev.of_node, "llink-connected", 0);
        if (!np) {
                dev_err(&op->dev, "could not find DMA node\n");
                rc = -ENODEV;
                goto err_iounmap;
        }

        /* Setup the DMA register accesses, could be DCR or memory mapped */
        if (temac_dcr_setup(lp, op, np)) {

                /* no DCR in the device tree, try non-DCR */
                lp->sdma_regs = of_iomap(np, 0);
                if (lp->sdma_regs) {
                        lp->dma_in = temac_dma_in32;
                        lp->dma_out = temac_dma_out32;
                        dev_dbg(&op->dev, "MEM base: %p\n", lp->sdma_regs);
                } else {
                        dev_err(&op->dev, "unable to map DMA registers\n");
                        of_node_put(np);
                        goto err_iounmap;
                }
        }

        lp->rx_irq = irq_of_parse_and_map(np, 0);
        lp->tx_irq = irq_of_parse_and_map(np, 1);

        of_node_put(np); /* Finished with the DMA node; drop the reference */

        if (!lp->rx_irq || !lp->tx_irq) {
                dev_err(&op->dev, "could not determine irqs\n");
                rc = -ENOMEM;
                goto err_iounmap_2;
        }


        /* Retrieve the MAC address */
        addr = of_get_property(op->dev.of_node, "local-mac-address", &size);
        if ((!addr) || (size != 6)) {
                dev_err(&op->dev, "could not find MAC address\n");
                rc = -ENODEV;
                goto err_iounmap_2;
        }
        temac_init_mac_address(ndev, (void *)addr);

        rc = temac_mdio_setup(lp, op->dev.of_node);
        if (rc)
                dev_warn(&op->dev, "error registering MDIO bus\n");

        lp->phy_node = of_parse_phandle(op->dev.of_node, "phy-handle", 0);
        if (lp->phy_node)
                dev_dbg(lp->dev, "using PHY node %s (%p)\n", np->full_name, np);

        /* Add the device attributes */
        rc = sysfs_create_group(&lp->dev->kobj, &temac_attr_group);
        if (rc) {
                dev_err(lp->dev, "Error creating sysfs files\n");
                goto err_iounmap_2;
        }

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

        return 0;

 err_register_ndev:
        sysfs_remove_group(&lp->dev->kobj, &temac_attr_group);
 err_iounmap_2:
        if (lp->sdma_regs)
                iounmap(lp->sdma_regs);
 err_iounmap:
        iounmap(lp->regs);
 nodev:
        free_netdev(ndev);
        ndev = NULL;
        return rc;
}

static int temac_of_remove(struct platform_device *op)
{
        struct net_device *ndev = platform_get_drvdata(op);
        struct temac_local *lp = netdev_priv(ndev);

        temac_mdio_teardown(lp);
        unregister_netdev(ndev);
        sysfs_remove_group(&lp->dev->kobj, &temac_attr_group);
        of_node_put(lp->phy_node);
        lp->phy_node = NULL;
        iounmap(lp->regs);
        if (lp->sdma_regs)
                iounmap(lp->sdma_regs);
        free_netdev(ndev);
        return 0;
}

static struct of_device_id temac_of_match[] = {
        { .compatible = "xlnx,xps-ll-temac-1.01.b", },
        { .compatible = "xlnx,xps-ll-temac-2.00.a", },
        { .compatible = "xlnx,xps-ll-temac-2.02.a", },
        { .compatible = "xlnx,xps-ll-temac-2.03.a", },
        {},
};
MODULE_DEVICE_TABLE(of, temac_of_match);

static struct platform_driver temac_of_driver = {
        .probe = temac_of_probe,
        .remove = temac_of_remove,
        .driver = {
                .name = "xilinx_temac",
                .of_match_table = temac_of_match,
        },
};

module_platform_driver(temac_of_driver);

MODULE_DESCRIPTION("Xilinx LL_TEMAC Ethernet driver");
MODULE_AUTHOR("Yoshio Kashiwagi");
MODULE_LICENSE("GPL");