Merge git://git.kvack.org/~bcrl/aio-next

[mirror_ubuntu-bionic-kernel.git] / drivers / net / ethernet / samsung / sxgbe / sxgbe_main.c

/* 10G controller driver for Samsung SoCs
 *
 * Copyright (C) 2013 Samsung Electronics Co., Ltd.
 *              http://www.samsung.com
 *
 * Author: Siva Reddy Kallam <siva.kallam@samsung.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/clk.h>
#include <linux/crc32.h>
#include <linux/dma-mapping.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/if.h>
#include <linux/if_ether.h>
#include <linux/if_vlan.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/ip.h>
#include <linux/kernel.h>
#include <linux/mii.h>
#include <linux/module.h>
#include <linux/net_tstamp.h>
#include <linux/netdevice.h>
#include <linux/phy.h>
#include <linux/platform_device.h>
#include <linux/prefetch.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/tcp.h>
#include <linux/sxgbe_platform.h>

#include "sxgbe_common.h"
#include "sxgbe_desc.h"
#include "sxgbe_dma.h"
#include "sxgbe_mtl.h"
#include "sxgbe_reg.h"

#define SXGBE_ALIGN(x)  L1_CACHE_ALIGN(x)
#define JUMBO_LEN       9000

/* Module parameters */
#define TX_TIMEO        5000
#define DMA_TX_SIZE     512
#define DMA_RX_SIZE     1024
#define TC_DEFAULT      64
#define DMA_BUFFER_SIZE BUF_SIZE_2KiB
/* The default timer value as per the sxgbe specification 1 sec(1000 ms) */
#define SXGBE_DEFAULT_LPI_TIMER 1000

static int debug = -1;
static int eee_timer = SXGBE_DEFAULT_LPI_TIMER;

module_param(eee_timer, int, S_IRUGO | S_IWUSR);

module_param(debug, int, S_IRUGO | S_IWUSR);
static const u32 default_msg_level = (NETIF_MSG_DRV | NETIF_MSG_PROBE |
                                      NETIF_MSG_LINK | NETIF_MSG_IFUP |
                                      NETIF_MSG_IFDOWN | NETIF_MSG_TIMER);

static irqreturn_t sxgbe_common_interrupt(int irq, void *dev_id);
static irqreturn_t sxgbe_tx_interrupt(int irq, void *dev_id);
static irqreturn_t sxgbe_rx_interrupt(int irq, void *dev_id);

#define SXGBE_COAL_TIMER(x) (jiffies + usecs_to_jiffies(x))

#define SXGBE_LPI_TIMER(x) (jiffies + msecs_to_jiffies(x))

/**
 * sxgbe_verify_args - verify the driver parameters.
 * Description: it verifies if some wrong parameter is passed to the driver.
 * Note that wrong parameters are replaced with the default values.
 */
static void sxgbe_verify_args(void)
{
        if (unlikely(eee_timer < 0))
                eee_timer = SXGBE_DEFAULT_LPI_TIMER;
}

static void sxgbe_enable_eee_mode(const struct sxgbe_priv_data *priv)
{
        /* Check and enter in LPI mode */
        if (!priv->tx_path_in_lpi_mode)
                priv->hw->mac->set_eee_mode(priv->ioaddr);
}

void sxgbe_disable_eee_mode(struct sxgbe_priv_data * const priv)
{
        /* Exit and disable EEE in case of we are are in LPI state. */
        priv->hw->mac->reset_eee_mode(priv->ioaddr);
        del_timer_sync(&priv->eee_ctrl_timer);
        priv->tx_path_in_lpi_mode = false;
}

/**
 * sxgbe_eee_ctrl_timer
 * @arg : data hook
 * Description:
 *  If there is no data transfer and if we are not in LPI state,
 *  then MAC Transmitter can be moved to LPI state.
 */
static void sxgbe_eee_ctrl_timer(unsigned long arg)
{
        struct sxgbe_priv_data *priv = (struct sxgbe_priv_data *)arg;

        sxgbe_enable_eee_mode(priv);
        mod_timer(&priv->eee_ctrl_timer, SXGBE_LPI_TIMER(eee_timer));
}

/**
 * sxgbe_eee_init
 * @priv: private device pointer
 * Description:
 *  If the EEE support has been enabled while configuring the driver,
 *  if the GMAC actually supports the EEE (from the HW cap reg) and the
 *  phy can also manage EEE, so enable the LPI state and start the timer
 *  to verify if the tx path can enter in LPI state.
 */
bool sxgbe_eee_init(struct sxgbe_priv_data * const priv)
{
        bool ret = false;

        /* MAC core supports the EEE feature. */
        if (priv->hw_cap.eee) {
                /* Check if the PHY supports EEE */
                if (phy_init_eee(priv->phydev, 1))
                        return false;

                priv->eee_active = 1;
                init_timer(&priv->eee_ctrl_timer);
                priv->eee_ctrl_timer.function = sxgbe_eee_ctrl_timer;
                priv->eee_ctrl_timer.data = (unsigned long)priv;
                priv->eee_ctrl_timer.expires = SXGBE_LPI_TIMER(eee_timer);
                add_timer(&priv->eee_ctrl_timer);

                priv->hw->mac->set_eee_timer(priv->ioaddr,
                                             SXGBE_DEFAULT_LPI_TIMER,
                                             priv->tx_lpi_timer);

                pr_info("Energy-Efficient Ethernet initialized\n");

                ret = true;
        }

        return ret;
}

static void sxgbe_eee_adjust(const struct sxgbe_priv_data *priv)
{
        /* When the EEE has been already initialised we have to
         * modify the PLS bit in the LPI ctrl & status reg according
         * to the PHY link status. For this reason.
         */
        if (priv->eee_enabled)
                priv->hw->mac->set_eee_pls(priv->ioaddr, priv->phydev->link);
}

/**
 * sxgbe_clk_csr_set - dynamically set the MDC clock
 * @priv: driver private structure
 * Description: this is to dynamically set the MDC clock according to the csr
 * clock input.
 */
static void sxgbe_clk_csr_set(struct sxgbe_priv_data *priv)
{
        u32 clk_rate = clk_get_rate(priv->sxgbe_clk);

        /* assign the proper divider, this will be used during
         * mdio communication
         */
        if (clk_rate < SXGBE_CSR_F_150M)
                priv->clk_csr = SXGBE_CSR_100_150M;
        else if (clk_rate <= SXGBE_CSR_F_250M)
                priv->clk_csr = SXGBE_CSR_150_250M;
        else if (clk_rate <= SXGBE_CSR_F_300M)
                priv->clk_csr = SXGBE_CSR_250_300M;
        else if (clk_rate <= SXGBE_CSR_F_350M)
                priv->clk_csr = SXGBE_CSR_300_350M;
        else if (clk_rate <= SXGBE_CSR_F_400M)
                priv->clk_csr = SXGBE_CSR_350_400M;
        else if (clk_rate <= SXGBE_CSR_F_500M)
                priv->clk_csr = SXGBE_CSR_400_500M;
}

/* minimum number of free TX descriptors required to wake up TX process */
#define SXGBE_TX_THRESH(x)      (x->dma_tx_size/4)

static inline u32 sxgbe_tx_avail(struct sxgbe_tx_queue *queue, int tx_qsize)
{
        return queue->dirty_tx + tx_qsize - queue->cur_tx - 1;
}

/**
 * sxgbe_adjust_link
 * @dev: net device structure
 * Description: it adjusts the link parameters.
 */
static void sxgbe_adjust_link(struct net_device *dev)
{
        struct sxgbe_priv_data *priv = netdev_priv(dev);
        struct phy_device *phydev = priv->phydev;
        u8 new_state = 0;
        u8 speed = 0xff;

        if (!phydev)
                return;

        /* SXGBE is not supporting auto-negotiation and
         * half duplex mode. so, not handling duplex change
         * in this function. only handling speed and link status
         */
        if (phydev->link) {
                if (phydev->speed != priv->speed) {
                        new_state = 1;
                        switch (phydev->speed) {
                        case SPEED_10000:
                                speed = SXGBE_SPEED_10G;
                                break;
                        case SPEED_2500:
                                speed = SXGBE_SPEED_2_5G;
                                break;
                        case SPEED_1000:
                                speed = SXGBE_SPEED_1G;
                                break;
                        default:
                                netif_err(priv, link, dev,
                                          "Speed (%d) not supported\n",
                                          phydev->speed);
                        }

                        priv->speed = phydev->speed;
                        priv->hw->mac->set_speed(priv->ioaddr, speed);
                }

                if (!priv->oldlink) {
                        new_state = 1;
                        priv->oldlink = 1;
                }
        } else if (priv->oldlink) {
                new_state = 1;
                priv->oldlink = 0;
                priv->speed = SPEED_UNKNOWN;
        }

        if (new_state & netif_msg_link(priv))
                phy_print_status(phydev);

        /* Alter the MAC settings for EEE */
        sxgbe_eee_adjust(priv);
}

/**
 * sxgbe_init_phy - PHY initialization
 * @dev: net device structure
 * Description: it initializes the driver's PHY state, and attaches the PHY
 * to the mac driver.
 *  Return value:
 *  0 on success
 */
static int sxgbe_init_phy(struct net_device *ndev)
{
        char phy_id_fmt[MII_BUS_ID_SIZE + 3];
        char bus_id[MII_BUS_ID_SIZE];
        struct phy_device *phydev;
        struct sxgbe_priv_data *priv = netdev_priv(ndev);
        int phy_iface = priv->plat->interface;

        /* assign default link status */
        priv->oldlink = 0;
        priv->speed = SPEED_UNKNOWN;
        priv->oldduplex = DUPLEX_UNKNOWN;

        if (priv->plat->phy_bus_name)
                snprintf(bus_id, MII_BUS_ID_SIZE, "%s-%x",
                         priv->plat->phy_bus_name, priv->plat->bus_id);
        else
                snprintf(bus_id, MII_BUS_ID_SIZE, "sxgbe-%x",
                         priv->plat->bus_id);

        snprintf(phy_id_fmt, MII_BUS_ID_SIZE + 3, PHY_ID_FMT, bus_id,
                 priv->plat->phy_addr);
        netdev_dbg(ndev, "%s: trying to attach to %s\n", __func__, phy_id_fmt);

        phydev = phy_connect(ndev, phy_id_fmt, &sxgbe_adjust_link, phy_iface);

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

        /* Stop Advertising 1000BASE Capability if interface is not GMII */
        if ((phy_iface == PHY_INTERFACE_MODE_MII) ||
            (phy_iface == PHY_INTERFACE_MODE_RMII))
                phydev->advertising &= ~(SUPPORTED_1000baseT_Half |
                                         SUPPORTED_1000baseT_Full);
        if (phydev->phy_id == 0) {
                phy_disconnect(phydev);
                return -ENODEV;
        }

        netdev_dbg(ndev, "%s: attached to PHY (UID 0x%x) Link = %d\n",
                   __func__, phydev->phy_id, phydev->link);

        /* save phy device in private structure */
        priv->phydev = phydev;

        return 0;
}

/**
 * sxgbe_clear_descriptors: clear descriptors
 * @priv: driver private structure
 * Description: this function is called to clear the tx and rx descriptors
 * in case of both basic and extended descriptors are used.
 */
static void sxgbe_clear_descriptors(struct sxgbe_priv_data *priv)
{
        int i, j;
        unsigned int txsize = priv->dma_tx_size;
        unsigned int rxsize = priv->dma_rx_size;

        /* Clear the Rx/Tx descriptors */
        for (j = 0; j < SXGBE_RX_QUEUES; j++) {
                for (i = 0; i < rxsize; i++)
                        priv->hw->desc->init_rx_desc(&priv->rxq[j]->dma_rx[i],
                                                     priv->use_riwt, priv->mode,
                                                     (i == rxsize - 1));
        }

        for (j = 0; j < SXGBE_TX_QUEUES; j++) {
                for (i = 0; i < txsize; i++)
                        priv->hw->desc->init_tx_desc(&priv->txq[j]->dma_tx[i]);
        }
}

static int sxgbe_init_rx_buffers(struct net_device *dev,
                                 struct sxgbe_rx_norm_desc *p, int i,
                                 unsigned int dma_buf_sz,
                                 struct sxgbe_rx_queue *rx_ring)
{
        struct sxgbe_priv_data *priv = netdev_priv(dev);
        struct sk_buff *skb;

        skb = __netdev_alloc_skb_ip_align(dev, dma_buf_sz, GFP_KERNEL);
        if (!skb)
                return -ENOMEM;

        rx_ring->rx_skbuff[i] = skb;
        rx_ring->rx_skbuff_dma[i] = dma_map_single(priv->device, skb->data,
                                                   dma_buf_sz, DMA_FROM_DEVICE);

        if (dma_mapping_error(priv->device, rx_ring->rx_skbuff_dma[i])) {
                netdev_err(dev, "%s: DMA mapping error\n", __func__);
                dev_kfree_skb_any(skb);
                return -EINVAL;
        }

        p->rdes23.rx_rd_des23.buf2_addr = rx_ring->rx_skbuff_dma[i];

        return 0;
}
/**
 * init_tx_ring - init the TX descriptor ring
 * @dev: net device structure
 * @tx_ring: ring to be intialised
 * @tx_rsize: ring size
 * Description:  this function initializes the DMA TX descriptor
 */
static int init_tx_ring(struct device *dev, u8 queue_no,
                        struct sxgbe_tx_queue *tx_ring, int tx_rsize)
{
        /* TX ring is not allcoated */
        if (!tx_ring) {
                dev_err(dev, "No memory for TX queue of SXGBE\n");
                return -ENOMEM;
        }

        /* allocate memory for TX descriptors */
        tx_ring->dma_tx = dma_zalloc_coherent(dev,
                                              tx_rsize * sizeof(struct sxgbe_tx_norm_desc),
                                              &tx_ring->dma_tx_phy, GFP_KERNEL);
        if (!tx_ring->dma_tx)
                return -ENOMEM;

        /* allocate memory for TX skbuff array */
        tx_ring->tx_skbuff_dma = devm_kcalloc(dev, tx_rsize,
                                              sizeof(dma_addr_t), GFP_KERNEL);
        if (!tx_ring->tx_skbuff_dma)
                goto dmamem_err;

        tx_ring->tx_skbuff = devm_kcalloc(dev, tx_rsize,
                                          sizeof(struct sk_buff *), GFP_KERNEL);

        if (!tx_ring->tx_skbuff)
                goto dmamem_err;

        /* assign queue number */
        tx_ring->queue_no = queue_no;

        /* initalise counters */
        tx_ring->dirty_tx = 0;
        tx_ring->cur_tx = 0;

        /* initalise TX queue lock */
        spin_lock_init(&tx_ring->tx_lock);

        return 0;

dmamem_err:
        dma_free_coherent(dev, tx_rsize * sizeof(struct sxgbe_tx_norm_desc),
                          tx_ring->dma_tx, tx_ring->dma_tx_phy);
        return -ENOMEM;
}

/**
 * free_rx_ring - free the RX descriptor ring
 * @dev: net device structure
 * @rx_ring: ring to be intialised
 * @rx_rsize: ring size
 * Description:  this function initializes the DMA RX descriptor
 */
void free_rx_ring(struct device *dev, struct sxgbe_rx_queue *rx_ring,
                  int rx_rsize)
{
        dma_free_coherent(dev, rx_rsize * sizeof(struct sxgbe_rx_norm_desc),
                          rx_ring->dma_rx, rx_ring->dma_rx_phy);
        kfree(rx_ring->rx_skbuff_dma);
        kfree(rx_ring->rx_skbuff);
}

/**
 * init_rx_ring - init the RX descriptor ring
 * @dev: net device structure
 * @rx_ring: ring to be intialised
 * @rx_rsize: ring size
 * Description:  this function initializes the DMA RX descriptor
 */
static int init_rx_ring(struct net_device *dev, u8 queue_no,
                        struct sxgbe_rx_queue *rx_ring, int rx_rsize)
{
        struct sxgbe_priv_data *priv = netdev_priv(dev);
        int desc_index;
        unsigned int bfsize = 0;
        unsigned int ret = 0;

        /* Set the max buffer size according to the MTU. */
        bfsize = ALIGN(dev->mtu + ETH_HLEN + ETH_FCS_LEN + NET_IP_ALIGN, 8);

        netif_dbg(priv, probe, dev, "%s: bfsize %d\n", __func__, bfsize);

        /* RX ring is not allcoated */
        if (rx_ring == NULL) {
                netdev_err(dev, "No memory for RX queue\n");
                goto error;
        }

        /* assign queue number */
        rx_ring->queue_no = queue_no;

        /* allocate memory for RX descriptors */
        rx_ring->dma_rx = dma_zalloc_coherent(priv->device,
                                              rx_rsize * sizeof(struct sxgbe_rx_norm_desc),
                                              &rx_ring->dma_rx_phy, GFP_KERNEL);

        if (rx_ring->dma_rx == NULL)
                goto error;

        /* allocate memory for RX skbuff array */
        rx_ring->rx_skbuff_dma = kmalloc_array(rx_rsize,
                                               sizeof(dma_addr_t), GFP_KERNEL);
        if (rx_ring->rx_skbuff_dma == NULL)
                goto dmamem_err;

        rx_ring->rx_skbuff = kmalloc_array(rx_rsize,
                                           sizeof(struct sk_buff *), GFP_KERNEL);
        if (rx_ring->rx_skbuff == NULL)
                goto rxbuff_err;

        /* initialise the buffers */
        for (desc_index = 0; desc_index < rx_rsize; desc_index++) {
                struct sxgbe_rx_norm_desc *p;
                p = rx_ring->dma_rx + desc_index;
                ret = sxgbe_init_rx_buffers(dev, p, desc_index,
                                            bfsize, rx_ring);
                if (ret)
                        goto err_init_rx_buffers;
        }

        /* initalise counters */
        rx_ring->cur_rx = 0;
        rx_ring->dirty_rx = (unsigned int)(desc_index - rx_rsize);
        priv->dma_buf_sz = bfsize;

        return 0;

err_init_rx_buffers:
        while (--desc_index >= 0)
                free_rx_ring(priv->device, rx_ring, desc_index);
        kfree(rx_ring->rx_skbuff);
rxbuff_err:
        kfree(rx_ring->rx_skbuff_dma);
dmamem_err:
        dma_free_coherent(priv->device,
                          rx_rsize * sizeof(struct sxgbe_rx_norm_desc),
                          rx_ring->dma_rx, rx_ring->dma_rx_phy);
error:
        return -ENOMEM;
}
/**
 * free_tx_ring - free the TX descriptor ring
 * @dev: net device structure
 * @tx_ring: ring to be intialised
 * @tx_rsize: ring size
 * Description:  this function initializes the DMA TX descriptor
 */
void free_tx_ring(struct device *dev, struct sxgbe_tx_queue *tx_ring,
                  int tx_rsize)
{
        dma_free_coherent(dev, tx_rsize * sizeof(struct sxgbe_tx_norm_desc),
                          tx_ring->dma_tx, tx_ring->dma_tx_phy);
}

/**
 * init_dma_desc_rings - init the RX/TX descriptor rings
 * @dev: net device structure
 * Description:  this function initializes the DMA RX/TX descriptors
 * and allocates the socket buffers. It suppors the chained and ring
 * modes.
 */
static int init_dma_desc_rings(struct net_device *netd)
{
        int queue_num, ret;
        struct sxgbe_priv_data *priv = netdev_priv(netd);
        int tx_rsize = priv->dma_tx_size;
        int rx_rsize = priv->dma_rx_size;

        /* Allocate memory for queue structures and TX descs */
        SXGBE_FOR_EACH_QUEUE(SXGBE_TX_QUEUES, queue_num) {
                ret = init_tx_ring(priv->device, queue_num,
                                   priv->txq[queue_num], tx_rsize);
                if (ret) {
                        dev_err(&netd->dev, "TX DMA ring allocation failed!\n");
                        goto txalloc_err;
                }

                /* save private pointer in each ring this
                 * pointer is needed during cleaing TX queue
                 */
                priv->txq[queue_num]->priv_ptr = priv;
        }

        /* Allocate memory for queue structures and RX descs */
        SXGBE_FOR_EACH_QUEUE(SXGBE_RX_QUEUES, queue_num) {
                ret = init_rx_ring(netd, queue_num,
                                   priv->rxq[queue_num], rx_rsize);
                if (ret) {
                        netdev_err(netd, "RX DMA ring allocation failed!!\n");
                        goto rxalloc_err;
                }

                /* save private pointer in each ring this
                 * pointer is needed during cleaing TX queue
                 */
                priv->rxq[queue_num]->priv_ptr = priv;
        }

        sxgbe_clear_descriptors(priv);

        return 0;

txalloc_err:
        while (queue_num--)
                free_tx_ring(priv->device, priv->txq[queue_num], tx_rsize);
        return ret;

rxalloc_err:
        while (queue_num--)
                free_rx_ring(priv->device, priv->rxq[queue_num], rx_rsize);
        return ret;
}

static void tx_free_ring_skbufs(struct sxgbe_tx_queue *txqueue)
{
        int dma_desc;
        struct sxgbe_priv_data *priv = txqueue->priv_ptr;
        int tx_rsize = priv->dma_tx_size;

        for (dma_desc = 0; dma_desc < tx_rsize; dma_desc++) {
                struct sxgbe_tx_norm_desc *tdesc = txqueue->dma_tx + dma_desc;

                if (txqueue->tx_skbuff_dma[dma_desc])
                        dma_unmap_single(priv->device,
                                         txqueue->tx_skbuff_dma[dma_desc],
                                         priv->hw->desc->get_tx_len(tdesc),
                                         DMA_TO_DEVICE);

                dev_kfree_skb_any(txqueue->tx_skbuff[dma_desc]);
                txqueue->tx_skbuff[dma_desc] = NULL;
                txqueue->tx_skbuff_dma[dma_desc] = 0;
        }
}


static void dma_free_tx_skbufs(struct sxgbe_priv_data *priv)
{
        int queue_num;

        SXGBE_FOR_EACH_QUEUE(SXGBE_TX_QUEUES, queue_num) {
                struct sxgbe_tx_queue *tqueue = priv->txq[queue_num];
                tx_free_ring_skbufs(tqueue);
        }
}

static void free_dma_desc_resources(struct sxgbe_priv_data *priv)
{
        int queue_num;
        int tx_rsize = priv->dma_tx_size;
        int rx_rsize = priv->dma_rx_size;

        /* Release the DMA TX buffers */
        dma_free_tx_skbufs(priv);

        /* Release the TX ring memory also */
        SXGBE_FOR_EACH_QUEUE(SXGBE_TX_QUEUES, queue_num) {
                free_tx_ring(priv->device, priv->txq[queue_num], tx_rsize);
        }

        /* Release the RX ring memory also */
        SXGBE_FOR_EACH_QUEUE(SXGBE_RX_QUEUES, queue_num) {
                free_rx_ring(priv->device, priv->rxq[queue_num], rx_rsize);
        }
}

static int txring_mem_alloc(struct sxgbe_priv_data *priv)
{
        int queue_num;

        SXGBE_FOR_EACH_QUEUE(SXGBE_TX_QUEUES, queue_num) {
                priv->txq[queue_num] = devm_kmalloc(priv->device,
                                                    sizeof(struct sxgbe_tx_queue), GFP_KERNEL);
                if (!priv->txq[queue_num])
                        return -ENOMEM;
        }

        return 0;
}

static int rxring_mem_alloc(struct sxgbe_priv_data *priv)
{
        int queue_num;

        SXGBE_FOR_EACH_QUEUE(SXGBE_RX_QUEUES, queue_num) {
                priv->rxq[queue_num] = devm_kmalloc(priv->device,
                                                    sizeof(struct sxgbe_rx_queue), GFP_KERNEL);
                if (!priv->rxq[queue_num])
                        return -ENOMEM;
        }

        return 0;
}

/**
 *  sxgbe_mtl_operation_mode - HW MTL operation mode
 *  @priv: driver private structure
 *  Description: it sets the MTL operation mode: tx/rx MTL thresholds
 *  or Store-And-Forward capability.
 */
static void sxgbe_mtl_operation_mode(struct sxgbe_priv_data *priv)
{
        int queue_num;

        /* TX/RX threshold control */
        if (likely(priv->plat->force_sf_dma_mode)) {
                /* set TC mode for TX QUEUES */
                SXGBE_FOR_EACH_QUEUE(priv->hw_cap.tx_mtl_queues, queue_num)
                        priv->hw->mtl->set_tx_mtl_mode(priv->ioaddr, queue_num,
                                                       SXGBE_MTL_SFMODE);
                priv->tx_tc = SXGBE_MTL_SFMODE;

                /* set TC mode for RX QUEUES */
                SXGBE_FOR_EACH_QUEUE(priv->hw_cap.rx_mtl_queues, queue_num)
                        priv->hw->mtl->set_rx_mtl_mode(priv->ioaddr, queue_num,
                                                       SXGBE_MTL_SFMODE);
                priv->rx_tc = SXGBE_MTL_SFMODE;
        } else if (unlikely(priv->plat->force_thresh_dma_mode)) {
                /* set TC mode for TX QUEUES */
                SXGBE_FOR_EACH_QUEUE(priv->hw_cap.tx_mtl_queues, queue_num)
                        priv->hw->mtl->set_tx_mtl_mode(priv->ioaddr, queue_num,
                                                       priv->tx_tc);
                /* set TC mode for RX QUEUES */
                SXGBE_FOR_EACH_QUEUE(priv->hw_cap.rx_mtl_queues, queue_num)
                        priv->hw->mtl->set_rx_mtl_mode(priv->ioaddr, queue_num,
                                                       priv->rx_tc);
        } else {
                pr_err("ERROR: %s: Invalid TX threshold mode\n", __func__);
        }
}

/**
 * sxgbe_tx_queue_clean:
 * @priv: driver private structure
 * Description: it reclaims resources after transmission completes.
 */
static void sxgbe_tx_queue_clean(struct sxgbe_tx_queue *tqueue)
{
        struct sxgbe_priv_data *priv = tqueue->priv_ptr;
        unsigned int tx_rsize = priv->dma_tx_size;
        struct netdev_queue *dev_txq;
        u8 queue_no = tqueue->queue_no;

        dev_txq = netdev_get_tx_queue(priv->dev, queue_no);

        spin_lock(&tqueue->tx_lock);

        priv->xstats.tx_clean++;
        while (tqueue->dirty_tx != tqueue->cur_tx) {
                unsigned int entry = tqueue->dirty_tx % tx_rsize;
                struct sk_buff *skb = tqueue->tx_skbuff[entry];
                struct sxgbe_tx_norm_desc *p;

                p = tqueue->dma_tx + entry;

                /* Check if the descriptor is owned by the DMA. */
                if (priv->hw->desc->get_tx_owner(p))
                        break;

                if (netif_msg_tx_done(priv))
                        pr_debug("%s: curr %d, dirty %d\n",
                                 __func__, tqueue->cur_tx, tqueue->dirty_tx);

                if (likely(tqueue->tx_skbuff_dma[entry])) {
                        dma_unmap_single(priv->device,
                                         tqueue->tx_skbuff_dma[entry],
                                         priv->hw->desc->get_tx_len(p),
                                         DMA_TO_DEVICE);
                        tqueue->tx_skbuff_dma[entry] = 0;
                }

                if (likely(skb)) {
                        dev_kfree_skb(skb);
                        tqueue->tx_skbuff[entry] = NULL;
                }

                priv->hw->desc->release_tx_desc(p);

                tqueue->dirty_tx++;
        }

        /* wake up queue */
        if (unlikely(netif_tx_queue_stopped(dev_txq) &&
                     sxgbe_tx_avail(tqueue, tx_rsize) > SXGBE_TX_THRESH(priv))) {
                netif_tx_lock(priv->dev);
                if (netif_tx_queue_stopped(dev_txq) &&
                    sxgbe_tx_avail(tqueue, tx_rsize) > SXGBE_TX_THRESH(priv)) {
                        if (netif_msg_tx_done(priv))
                                pr_debug("%s: restart transmit\n", __func__);
                        netif_tx_wake_queue(dev_txq);
                }
                netif_tx_unlock(priv->dev);
        }

        spin_unlock(&tqueue->tx_lock);
}

/**
 * sxgbe_tx_clean:
 * @priv: driver private structure
 * Description: it reclaims resources after transmission completes.
 */
static void sxgbe_tx_all_clean(struct sxgbe_priv_data * const priv)
{
        u8 queue_num;

        SXGBE_FOR_EACH_QUEUE(SXGBE_TX_QUEUES, queue_num) {
                struct sxgbe_tx_queue *tqueue = priv->txq[queue_num];

                sxgbe_tx_queue_clean(tqueue);
        }

        if ((priv->eee_enabled) && (!priv->tx_path_in_lpi_mode)) {
                sxgbe_enable_eee_mode(priv);
                mod_timer(&priv->eee_ctrl_timer, SXGBE_LPI_TIMER(eee_timer));
        }
}

/**
 * sxgbe_restart_tx_queue: irq tx error mng function
 * @priv: driver private structure
 * Description: it cleans the descriptors and restarts the transmission
 * in case of errors.
 */
static void sxgbe_restart_tx_queue(struct sxgbe_priv_data *priv, int queue_num)
{
        struct sxgbe_tx_queue *tx_ring = priv->txq[queue_num];
        struct netdev_queue *dev_txq = netdev_get_tx_queue(priv->dev,
                                                           queue_num);

        /* stop the queue */
        netif_tx_stop_queue(dev_txq);

        /* stop the tx dma */
        priv->hw->dma->stop_tx_queue(priv->ioaddr, queue_num);

        /* free the skbuffs of the ring */
        tx_free_ring_skbufs(tx_ring);

        /* initalise counters */
        tx_ring->cur_tx = 0;
        tx_ring->dirty_tx = 0;

        /* start the tx dma */
        priv->hw->dma->start_tx_queue(priv->ioaddr, queue_num);

        priv->dev->stats.tx_errors++;

        /* wakeup the queue */
        netif_tx_wake_queue(dev_txq);
}

/**
 * sxgbe_reset_all_tx_queues: irq tx error mng function
 * @priv: driver private structure
 * Description: it cleans all the descriptors and
 * restarts the transmission on all queues in case of errors.
 */
static void sxgbe_reset_all_tx_queues(struct sxgbe_priv_data *priv)
{
        int queue_num;

        /* On TX timeout of net device, resetting of all queues
         * may not be proper way, revisit this later if needed
         */
        SXGBE_FOR_EACH_QUEUE(SXGBE_TX_QUEUES, queue_num)
                sxgbe_restart_tx_queue(priv, queue_num);
}

/**
 * sxgbe_get_hw_features: get XMAC capabilities from the HW cap. register.
 * @priv: driver private structure
 * Description:
 *  new GMAC chip generations have a new register to indicate the
 *  presence of the optional feature/functions.
 *  This can be also used to override the value passed through the
 *  platform and necessary for old MAC10/100 and GMAC chips.
 */
static int sxgbe_get_hw_features(struct sxgbe_priv_data * const priv)
{
        int rval = 0;
        struct sxgbe_hw_features *features = &priv->hw_cap;

        /* Read First Capability Register CAP[0] */
        rval = priv->hw->mac->get_hw_feature(priv->ioaddr, 0);
        if (rval) {
                features->pmt_remote_wake_up =
                        SXGBE_HW_FEAT_PMT_TEMOTE_WOP(rval);
                features->pmt_magic_frame = SXGBE_HW_FEAT_PMT_MAGIC_PKT(rval);
                features->atime_stamp = SXGBE_HW_FEAT_IEEE1500_2008(rval);
                features->tx_csum_offload =
                        SXGBE_HW_FEAT_TX_CSUM_OFFLOAD(rval);
                features->rx_csum_offload =
                        SXGBE_HW_FEAT_RX_CSUM_OFFLOAD(rval);
                features->multi_macaddr = SXGBE_HW_FEAT_MACADDR_COUNT(rval);
                features->tstamp_srcselect = SXGBE_HW_FEAT_TSTMAP_SRC(rval);
                features->sa_vlan_insert = SXGBE_HW_FEAT_SRCADDR_VLAN(rval);
                features->eee = SXGBE_HW_FEAT_EEE(rval);
        }

        /* Read First Capability Register CAP[1] */
        rval = priv->hw->mac->get_hw_feature(priv->ioaddr, 1);
        if (rval) {
                features->rxfifo_size = SXGBE_HW_FEAT_RX_FIFO_SIZE(rval);
                features->txfifo_size = SXGBE_HW_FEAT_TX_FIFO_SIZE(rval);
                features->atstmap_hword = SXGBE_HW_FEAT_TX_FIFO_SIZE(rval);
                features->dcb_enable = SXGBE_HW_FEAT_DCB(rval);
                features->splithead_enable = SXGBE_HW_FEAT_SPLIT_HDR(rval);
                features->tcpseg_offload = SXGBE_HW_FEAT_TSO(rval);
                features->debug_mem = SXGBE_HW_FEAT_DEBUG_MEM_IFACE(rval);
                features->rss_enable = SXGBE_HW_FEAT_RSS(rval);
                features->hash_tsize = SXGBE_HW_FEAT_HASH_TABLE_SIZE(rval);
                features->l3l4_filer_size = SXGBE_HW_FEAT_L3L4_FILTER_NUM(rval);
        }

        /* Read First Capability Register CAP[2] */
        rval = priv->hw->mac->get_hw_feature(priv->ioaddr, 2);
        if (rval) {
                features->rx_mtl_queues = SXGBE_HW_FEAT_RX_MTL_QUEUES(rval);
                features->tx_mtl_queues = SXGBE_HW_FEAT_TX_MTL_QUEUES(rval);
                features->rx_dma_channels = SXGBE_HW_FEAT_RX_DMA_CHANNELS(rval);
                features->tx_dma_channels = SXGBE_HW_FEAT_TX_DMA_CHANNELS(rval);
                features->pps_output_count = SXGBE_HW_FEAT_PPS_OUTPUTS(rval);
                features->aux_input_count = SXGBE_HW_FEAT_AUX_SNAPSHOTS(rval);
        }

        return rval;
}

/**
 * sxgbe_check_ether_addr: check if the MAC addr is valid
 * @priv: driver private structure
 * Description:
 * it is to verify if the MAC address is valid, in case of failures it
 * generates a random MAC address
 */
static void sxgbe_check_ether_addr(struct sxgbe_priv_data *priv)
{
        if (!is_valid_ether_addr(priv->dev->dev_addr)) {
                priv->hw->mac->get_umac_addr((void __iomem *)
                                             priv->ioaddr,
                                             priv->dev->dev_addr, 0);
                if (!is_valid_ether_addr(priv->dev->dev_addr))
                        eth_hw_addr_random(priv->dev);
        }
        dev_info(priv->device, "device MAC address %pM\n",
                 priv->dev->dev_addr);
}

/**
 * sxgbe_init_dma_engine: DMA init.
 * @priv: driver private structure
 * Description:
 * It inits the DMA invoking the specific SXGBE callback.
 * Some DMA parameters can be passed from the platform;
 * in case of these are not passed a default is kept for the MAC or GMAC.
 */
static int sxgbe_init_dma_engine(struct sxgbe_priv_data *priv)
{
        int pbl = DEFAULT_DMA_PBL, fixed_burst = 0, burst_map = 0;
        int queue_num;

        if (priv->plat->dma_cfg) {
                pbl = priv->plat->dma_cfg->pbl;
                fixed_burst = priv->plat->dma_cfg->fixed_burst;
                burst_map = priv->plat->dma_cfg->burst_map;
        }

        SXGBE_FOR_EACH_QUEUE(SXGBE_TX_QUEUES, queue_num)
                priv->hw->dma->cha_init(priv->ioaddr, queue_num,
                                        fixed_burst, pbl,
                                        (priv->txq[queue_num])->dma_tx_phy,
                                        (priv->rxq[queue_num])->dma_rx_phy,
                                        priv->dma_tx_size, priv->dma_rx_size);

        return priv->hw->dma->init(priv->ioaddr, fixed_burst, burst_map);
}

/**
 * sxgbe_init_mtl_engine: MTL init.
 * @priv: driver private structure
 * Description:
 * It inits the MTL invoking the specific SXGBE callback.
 */
static void sxgbe_init_mtl_engine(struct sxgbe_priv_data *priv)
{
        int queue_num;

        SXGBE_FOR_EACH_QUEUE(SXGBE_TX_QUEUES, queue_num) {
                priv->hw->mtl->mtl_set_txfifosize(priv->ioaddr, queue_num,
                                                  priv->hw_cap.tx_mtl_qsize);
                priv->hw->mtl->mtl_enable_txqueue(priv->ioaddr, queue_num);
        }
}

/**
 * sxgbe_disable_mtl_engine: MTL disable.
 * @priv: driver private structure
 * Description:
 * It disables the MTL queues by invoking the specific SXGBE callback.
 */
static void sxgbe_disable_mtl_engine(struct sxgbe_priv_data *priv)
{
        int queue_num;

        SXGBE_FOR_EACH_QUEUE(SXGBE_TX_QUEUES, queue_num)
                priv->hw->mtl->mtl_disable_txqueue(priv->ioaddr, queue_num);
}


/**
 * sxgbe_tx_timer: mitigation sw timer for tx.
 * @data: data pointer
 * Description:
 * This is the timer handler to directly invoke the sxgbe_tx_clean.
 */
static void sxgbe_tx_timer(unsigned long data)
{
        struct sxgbe_tx_queue *p = (struct sxgbe_tx_queue *)data;
        sxgbe_tx_queue_clean(p);
}

/**
 * sxgbe_init_tx_coalesce: init tx mitigation options.
 * @priv: driver private structure
 * Description:
 * This inits the transmit coalesce parameters: i.e. timer rate,
 * timer handler and default threshold used for enabling the
 * interrupt on completion bit.
 */
static void sxgbe_tx_init_coalesce(struct sxgbe_priv_data *priv)
{
        u8 queue_num;

        SXGBE_FOR_EACH_QUEUE(SXGBE_TX_QUEUES, queue_num) {
                struct sxgbe_tx_queue *p = priv->txq[queue_num];
                p->tx_coal_frames =  SXGBE_TX_FRAMES;
                p->tx_coal_timer = SXGBE_COAL_TX_TIMER;
                init_timer(&p->txtimer);
                p->txtimer.expires = SXGBE_COAL_TIMER(p->tx_coal_timer);
                p->txtimer.data = (unsigned long)&priv->txq[queue_num];
                p->txtimer.function = sxgbe_tx_timer;
                add_timer(&p->txtimer);
        }
}

static void sxgbe_tx_del_timer(struct sxgbe_priv_data *priv)
{
        u8 queue_num;

        SXGBE_FOR_EACH_QUEUE(SXGBE_TX_QUEUES, queue_num) {
                struct sxgbe_tx_queue *p = priv->txq[queue_num];
                del_timer_sync(&p->txtimer);
        }
}

/**
 *  sxgbe_open - open entry point of the driver
 *  @dev : pointer to the device structure.
 *  Description:
 *  This function is the open entry point of the driver.
 *  Return value:
 *  0 on success and an appropriate (-)ve integer as defined in errno.h
 *  file on failure.
 */
static int sxgbe_open(struct net_device *dev)
{
        struct sxgbe_priv_data *priv = netdev_priv(dev);
        int ret, queue_num;

        clk_prepare_enable(priv->sxgbe_clk);

        sxgbe_check_ether_addr(priv);

        /* Init the phy */
        ret = sxgbe_init_phy(dev);
        if (ret) {
                netdev_err(dev, "%s: Cannot attach to PHY (error: %d)\n",
                           __func__, ret);
                goto phy_error;
        }

        /* Create and initialize the TX/RX descriptors chains. */
        priv->dma_tx_size = SXGBE_ALIGN(DMA_TX_SIZE);
        priv->dma_rx_size = SXGBE_ALIGN(DMA_RX_SIZE);
        priv->dma_buf_sz = SXGBE_ALIGN(DMA_BUFFER_SIZE);
        priv->tx_tc = TC_DEFAULT;
        priv->rx_tc = TC_DEFAULT;
        init_dma_desc_rings(dev);

        /* DMA initialization and SW reset */
        ret = sxgbe_init_dma_engine(priv);
        if (ret < 0) {
                netdev_err(dev, "%s: DMA initialization failed\n", __func__);
                goto init_error;
        }

        /*  MTL initialization */
        sxgbe_init_mtl_engine(priv);

        /* Copy the MAC addr into the HW  */
        priv->hw->mac->set_umac_addr(priv->ioaddr, dev->dev_addr, 0);

        /* Initialize the MAC Core */
        priv->hw->mac->core_init(priv->ioaddr);

        /* Request the IRQ lines */
        ret = devm_request_irq(priv->device, priv->irq, sxgbe_common_interrupt,
                               IRQF_SHARED, dev->name, dev);
        if (unlikely(ret < 0)) {
                netdev_err(dev, "%s: ERROR: allocating the IRQ %d (error: %d)\n",
                           __func__, priv->irq, ret);
                goto init_error;
        }

        /* If the LPI irq is different from the mac irq
         * register a dedicated handler
         */
        if (priv->lpi_irq != dev->irq) {
                ret = devm_request_irq(priv->device, priv->lpi_irq,
                                       sxgbe_common_interrupt,
                                       IRQF_SHARED, dev->name, dev);
                if (unlikely(ret < 0)) {
                        netdev_err(dev, "%s: ERROR: allocating the LPI IRQ %d (%d)\n",
                                   __func__, priv->lpi_irq, ret);
                        goto init_error;
                }
        }

        /* Request TX DMA irq lines */
        SXGBE_FOR_EACH_QUEUE(SXGBE_TX_QUEUES, queue_num) {
                ret = devm_request_irq(priv->device,
                                       (priv->txq[queue_num])->irq_no,
                                       sxgbe_tx_interrupt, 0,
                                       dev->name, priv->txq[queue_num]);
                if (unlikely(ret < 0)) {
                        netdev_err(dev, "%s: ERROR: allocating TX IRQ %d (error: %d)\n",
                                   __func__, priv->irq, ret);
                        goto init_error;
                }
        }

        /* Request RX DMA irq lines */
        SXGBE_FOR_EACH_QUEUE(SXGBE_RX_QUEUES, queue_num) {
                ret = devm_request_irq(priv->device,
                                       (priv->rxq[queue_num])->irq_no,
                                       sxgbe_rx_interrupt, 0,
                                       dev->name, priv->rxq[queue_num]);
                if (unlikely(ret < 0)) {
                        netdev_err(dev, "%s: ERROR: allocating TX IRQ %d (error: %d)\n",
                                   __func__, priv->irq, ret);
                        goto init_error;
                }
        }

        /* Enable the MAC Rx/Tx */
        priv->hw->mac->enable_tx(priv->ioaddr, true);
        priv->hw->mac->enable_rx(priv->ioaddr, true);

        /* Set the HW DMA mode and the COE */
        sxgbe_mtl_operation_mode(priv);

        /* Extra statistics */
        memset(&priv->xstats, 0, sizeof(struct sxgbe_extra_stats));

        priv->xstats.tx_threshold = priv->tx_tc;
        priv->xstats.rx_threshold = priv->rx_tc;

        /* Start the ball rolling... */
        netdev_dbg(dev, "DMA RX/TX processes started...\n");
        priv->hw->dma->start_tx(priv->ioaddr, SXGBE_TX_QUEUES);
        priv->hw->dma->start_rx(priv->ioaddr, SXGBE_RX_QUEUES);

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

        /* initalise TX coalesce parameters */
        sxgbe_tx_init_coalesce(priv);

        if ((priv->use_riwt) && (priv->hw->dma->rx_watchdog)) {
                priv->rx_riwt = SXGBE_MAX_DMA_RIWT;
                priv->hw->dma->rx_watchdog(priv->ioaddr, SXGBE_MAX_DMA_RIWT);
        }

        priv->tx_lpi_timer = SXGBE_DEFAULT_LPI_TIMER;
        priv->eee_enabled = sxgbe_eee_init(priv);

        napi_enable(&priv->napi);
        netif_start_queue(dev);

        return 0;

init_error:
        free_dma_desc_resources(priv);
        if (priv->phydev)
                phy_disconnect(priv->phydev);
phy_error:
        clk_disable_unprepare(priv->sxgbe_clk);

        return ret;
}

/**
 *  sxgbe_release - close entry point of the driver
 *  @dev : device pointer.
 *  Description:
 *  This is the stop entry point of the driver.
 */
static int sxgbe_release(struct net_device *dev)
{
        struct sxgbe_priv_data *priv = netdev_priv(dev);

        if (priv->eee_enabled)
                del_timer_sync(&priv->eee_ctrl_timer);

        /* Stop and disconnect the PHY */
        if (priv->phydev) {
                phy_stop(priv->phydev);
                phy_disconnect(priv->phydev);
                priv->phydev = NULL;
        }

        netif_tx_stop_all_queues(dev);

        napi_disable(&priv->napi);

        /* delete TX timers */
        sxgbe_tx_del_timer(priv);

        /* Stop TX/RX DMA and clear the descriptors */
        priv->hw->dma->stop_tx(priv->ioaddr, SXGBE_TX_QUEUES);
        priv->hw->dma->stop_rx(priv->ioaddr, SXGBE_RX_QUEUES);

        /* disable MTL queue */
        sxgbe_disable_mtl_engine(priv);

        /* Release and free the Rx/Tx resources */
        free_dma_desc_resources(priv);

        /* Disable the MAC Rx/Tx */
        priv->hw->mac->enable_tx(priv->ioaddr, false);
        priv->hw->mac->enable_rx(priv->ioaddr, false);

        clk_disable_unprepare(priv->sxgbe_clk);

        return 0;
}

/* Prepare first Tx descriptor for doing TSO operation */
void sxgbe_tso_prepare(struct sxgbe_priv_data *priv,
                       struct sxgbe_tx_norm_desc *first_desc,
                       struct sk_buff *skb)
{
        unsigned int total_hdr_len, tcp_hdr_len;

        /* Write first Tx descriptor with appropriate value */
        tcp_hdr_len = tcp_hdrlen(skb);
        total_hdr_len = skb_transport_offset(skb) + tcp_hdr_len;

        first_desc->tdes01 = dma_map_single(priv->device, skb->data,
                                            total_hdr_len, DMA_TO_DEVICE);
        if (dma_mapping_error(priv->device, first_desc->tdes01))
                pr_err("%s: TX dma mapping failed!!\n", __func__);

        first_desc->tdes23.tx_rd_des23.first_desc = 1;
        priv->hw->desc->tx_desc_enable_tse(first_desc, 1, total_hdr_len,
                                           tcp_hdr_len,
                                           skb->len - total_hdr_len);
}

/**
 *  sxgbe_xmit: Tx entry point of the driver
 *  @skb : the socket buffer
 *  @dev : device pointer
 *  Description : this is the tx entry point of the driver.
 *  It programs the chain or the ring and supports oversized frames
 *  and SG feature.
 */
static netdev_tx_t sxgbe_xmit(struct sk_buff *skb, struct net_device *dev)
{
        unsigned int entry, frag_num;
        int cksum_flag = 0;
        struct netdev_queue *dev_txq;
        unsigned txq_index = skb_get_queue_mapping(skb);
        struct sxgbe_priv_data *priv = netdev_priv(dev);
        unsigned int tx_rsize = priv->dma_tx_size;
        struct sxgbe_tx_queue *tqueue = priv->txq[txq_index];
        struct sxgbe_tx_norm_desc *tx_desc, *first_desc;
        struct sxgbe_tx_ctxt_desc *ctxt_desc = NULL;
        int nr_frags = skb_shinfo(skb)->nr_frags;
        int no_pagedlen = skb_headlen(skb);
        int is_jumbo = 0;
        u16 cur_mss = skb_shinfo(skb)->gso_size;
        u32 ctxt_desc_req = 0;

        /* get the TX queue handle */
        dev_txq = netdev_get_tx_queue(dev, txq_index);

        if (unlikely(skb_is_gso(skb) && tqueue->prev_mss != cur_mss))
                ctxt_desc_req = 1;

        if (unlikely(vlan_tx_tag_present(skb) ||
                     ((skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) &&
                      tqueue->hwts_tx_en)))
                ctxt_desc_req = 1;

        /* get the spinlock */
        spin_lock(&tqueue->tx_lock);

        if (priv->tx_path_in_lpi_mode)
                sxgbe_disable_eee_mode(priv);

        if (unlikely(sxgbe_tx_avail(tqueue, tx_rsize) < nr_frags + 1)) {
                if (!netif_tx_queue_stopped(dev_txq)) {
                        netif_tx_stop_queue(dev_txq);
                        netdev_err(dev, "%s: Tx Ring is full when %d queue is awake\n",
                                   __func__, txq_index);
                }
                /* release the spin lock in case of BUSY */
                spin_unlock(&tqueue->tx_lock);
                return NETDEV_TX_BUSY;
        }

        entry = tqueue->cur_tx % tx_rsize;
        tx_desc = tqueue->dma_tx + entry;

        first_desc = tx_desc;
        if (ctxt_desc_req)
                ctxt_desc = (struct sxgbe_tx_ctxt_desc *)first_desc;

        /* save the skb address */
        tqueue->tx_skbuff[entry] = skb;

        if (!is_jumbo) {
                if (likely(skb_is_gso(skb))) {
                        /* TSO support */
                        if (unlikely(tqueue->prev_mss != cur_mss)) {
                                priv->hw->desc->tx_ctxt_desc_set_mss(
                                                ctxt_desc, cur_mss);
                                priv->hw->desc->tx_ctxt_desc_set_tcmssv(
                                                ctxt_desc);
                                priv->hw->desc->tx_ctxt_desc_reset_ostc(
                                                ctxt_desc);
                                priv->hw->desc->tx_ctxt_desc_set_ctxt(
                                                ctxt_desc);
                                priv->hw->desc->tx_ctxt_desc_set_owner(
                                                ctxt_desc);

                                entry = (++tqueue->cur_tx) % tx_rsize;
                                first_desc = tqueue->dma_tx + entry;

                                tqueue->prev_mss = cur_mss;
                        }
                        sxgbe_tso_prepare(priv, first_desc, skb);
                } else {
                        tx_desc->tdes01 = dma_map_single(priv->device,
                                                         skb->data, no_pagedlen, DMA_TO_DEVICE);
                        if (dma_mapping_error(priv->device, tx_desc->tdes01))
                                netdev_err(dev, "%s: TX dma mapping failed!!\n",
                                           __func__);

                        priv->hw->desc->prepare_tx_desc(tx_desc, 1, no_pagedlen,
                                                        no_pagedlen, cksum_flag);
                }
        }

        for (frag_num = 0; frag_num < nr_frags; frag_num++) {
                const skb_frag_t *frag = &skb_shinfo(skb)->frags[frag_num];
                int len = skb_frag_size(frag);

                entry = (++tqueue->cur_tx) % tx_rsize;
                tx_desc = tqueue->dma_tx + entry;
                tx_desc->tdes01 = skb_frag_dma_map(priv->device, frag, 0, len,
                                                   DMA_TO_DEVICE);

                tqueue->tx_skbuff_dma[entry] = tx_desc->tdes01;
                tqueue->tx_skbuff[entry] = NULL;

                /* prepare the descriptor */
                priv->hw->desc->prepare_tx_desc(tx_desc, 0, len,
                                                len, cksum_flag);
                /* memory barrier to flush descriptor */
                wmb();

                /* set the owner */
                priv->hw->desc->set_tx_owner(tx_desc);
        }

        /* close the descriptors */
        priv->hw->desc->close_tx_desc(tx_desc);

        /* memory barrier to flush descriptor */
        wmb();

        tqueue->tx_count_frames += nr_frags + 1;
        if (tqueue->tx_count_frames > tqueue->tx_coal_frames) {
                priv->hw->desc->clear_tx_ic(tx_desc);
                priv->xstats.tx_reset_ic_bit++;
                mod_timer(&tqueue->txtimer,
                          SXGBE_COAL_TIMER(tqueue->tx_coal_timer));
        } else {
                tqueue->tx_count_frames = 0;
        }

        /* set owner for first desc */
        priv->hw->desc->set_tx_owner(first_desc);

        /* memory barrier to flush descriptor */
        wmb();

        tqueue->cur_tx++;

        /* display current ring */
        netif_dbg(priv, pktdata, dev, "%s: curr %d dirty=%d entry=%d, first=%p, nfrags=%d\n",
                  __func__, tqueue->cur_tx % tx_rsize,
                  tqueue->dirty_tx % tx_rsize, entry,
                  first_desc, nr_frags);

        if (unlikely(sxgbe_tx_avail(tqueue, tx_rsize) <= (MAX_SKB_FRAGS + 1))) {
                netif_dbg(priv, hw, dev, "%s: stop transmitted packets\n",
                          __func__);
                netif_tx_stop_queue(dev_txq);
        }

        dev->stats.tx_bytes += skb->len;

        if (unlikely((skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) &&
                     tqueue->hwts_tx_en)) {
                /* declare that device is doing timestamping */
                skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
                priv->hw->desc->tx_enable_tstamp(first_desc);
        }

        if (!tqueue->hwts_tx_en)
                skb_tx_timestamp(skb);

        priv->hw->dma->enable_dma_transmission(priv->ioaddr, txq_index);

        spin_unlock(&tqueue->tx_lock);

        return NETDEV_TX_OK;
}

/**
 * sxgbe_rx_refill: refill used skb preallocated buffers
 * @priv: driver private structure
 * Description : this is to reallocate the skb for the reception process
 * that is based on zero-copy.
 */
static void sxgbe_rx_refill(struct sxgbe_priv_data *priv)
{
        unsigned int rxsize = priv->dma_rx_size;
        int bfsize = priv->dma_buf_sz;
        u8 qnum = priv->cur_rx_qnum;

        for (; priv->rxq[qnum]->cur_rx - priv->rxq[qnum]->dirty_rx > 0;
             priv->rxq[qnum]->dirty_rx++) {
                unsigned int entry = priv->rxq[qnum]->dirty_rx % rxsize;
                struct sxgbe_rx_norm_desc *p;

                p = priv->rxq[qnum]->dma_rx + entry;

                if (likely(priv->rxq[qnum]->rx_skbuff[entry] == NULL)) {
                        struct sk_buff *skb;

                        skb = netdev_alloc_skb_ip_align(priv->dev, bfsize);

                        if (unlikely(skb == NULL))
                                break;

                        priv->rxq[qnum]->rx_skbuff[entry] = skb;
                        priv->rxq[qnum]->rx_skbuff_dma[entry] =
                                dma_map_single(priv->device, skb->data, bfsize,
                                               DMA_FROM_DEVICE);

                        p->rdes23.rx_rd_des23.buf2_addr =
                                priv->rxq[qnum]->rx_skbuff_dma[entry];
                }

                /* Added memory barrier for RX descriptor modification */
                wmb();
                priv->hw->desc->set_rx_owner(p);
                /* Added memory barrier for RX descriptor modification */
                wmb();
        }
}

/**
 * sxgbe_rx: receive the frames from the remote host
 * @priv: driver private structure
 * @limit: napi bugget.
 * Description :  this the function called by the napi poll method.
 * It gets all the frames inside the ring.
 */
static int sxgbe_rx(struct sxgbe_priv_data *priv, int limit)
{
        u8 qnum = priv->cur_rx_qnum;
        unsigned int rxsize = priv->dma_rx_size;
        unsigned int entry = priv->rxq[qnum]->cur_rx;
        unsigned int next_entry = 0;
        unsigned int count = 0;
        int checksum;
        int status;

        while (count < limit) {
                struct sxgbe_rx_norm_desc *p;
                struct sk_buff *skb;
                int frame_len;

                p = priv->rxq[qnum]->dma_rx + entry;

                if (priv->hw->desc->get_rx_owner(p))
                        break;

                count++;

                next_entry = (++priv->rxq[qnum]->cur_rx) % rxsize;
                prefetch(priv->rxq[qnum]->dma_rx + next_entry);

                /* Read the status of the incoming frame and also get checksum
                 * value based on whether it is enabled in SXGBE hardware or
                 * not.
                 */
                status = priv->hw->desc->rx_wbstatus(p, &priv->xstats,
                                                     &checksum);
                if (unlikely(status < 0)) {
                        entry = next_entry;
                        continue;
                }
                if (unlikely(!priv->rxcsum_insertion))
                        checksum = CHECKSUM_NONE;

                skb = priv->rxq[qnum]->rx_skbuff[entry];

                if (unlikely(!skb))
                        netdev_err(priv->dev, "rx descriptor is not consistent\n");

                prefetch(skb->data - NET_IP_ALIGN);
                priv->rxq[qnum]->rx_skbuff[entry] = NULL;

                frame_len = priv->hw->desc->get_rx_frame_len(p);

                skb_put(skb, frame_len);

                skb->ip_summed = checksum;
                if (checksum == CHECKSUM_NONE)
                        netif_receive_skb(skb);
                else
                        napi_gro_receive(&priv->napi, skb);

                entry = next_entry;
        }

        sxgbe_rx_refill(priv);

        return count;
}

/**
 *  sxgbe_poll - sxgbe poll method (NAPI)
 *  @napi : pointer to the napi structure.
 *  @budget : maximum number of packets that the current CPU can receive from
 *            all interfaces.
 *  Description :
 *  To look at the incoming frames and clear the tx resources.
 */
static int sxgbe_poll(struct napi_struct *napi, int budget)
{
        struct sxgbe_priv_data *priv = container_of(napi,
                                                    struct sxgbe_priv_data, napi);
        int work_done = 0;
        u8 qnum = priv->cur_rx_qnum;

        priv->xstats.napi_poll++;
        /* first, clean the tx queues */
        sxgbe_tx_all_clean(priv);

        work_done = sxgbe_rx(priv, budget);
        if (work_done < budget) {
                napi_complete(napi);
                priv->hw->dma->enable_dma_irq(priv->ioaddr, qnum);
        }

        return work_done;
}

/**
 *  sxgbe_tx_timeout
 *  @dev : Pointer to net device structure
 *  Description: this function is called when a packet transmission fails to
 *   complete within a reasonable time. The driver will mark the error in the
 *   netdev structure and arrange for the device to be reset to a sane state
 *   in order to transmit a new packet.
 */
static void sxgbe_tx_timeout(struct net_device *dev)
{
        struct sxgbe_priv_data *priv = netdev_priv(dev);

        sxgbe_reset_all_tx_queues(priv);
}

/**
 *  sxgbe_common_interrupt - main ISR
 *  @irq: interrupt number.
 *  @dev_id: to pass the net device pointer.
 *  Description: this is the main driver interrupt service routine.
 *  It calls the DMA ISR and also the core ISR to manage PMT, MMC, LPI
 *  interrupts.
 */
static irqreturn_t sxgbe_common_interrupt(int irq, void *dev_id)
{
        struct net_device *netdev = (struct net_device *)dev_id;
        struct sxgbe_priv_data *priv = netdev_priv(netdev);
        int status;

        status = priv->hw->mac->host_irq_status(priv->ioaddr, &priv->xstats);
        /* For LPI we need to save the tx status */
        if (status & TX_ENTRY_LPI_MODE) {
                priv->xstats.tx_lpi_entry_n++;
                priv->tx_path_in_lpi_mode = true;
        }
        if (status & TX_EXIT_LPI_MODE) {
                priv->xstats.tx_lpi_exit_n++;
                priv->tx_path_in_lpi_mode = false;
        }
        if (status & RX_ENTRY_LPI_MODE)
                priv->xstats.rx_lpi_entry_n++;
        if (status & RX_EXIT_LPI_MODE)
                priv->xstats.rx_lpi_exit_n++;

        return IRQ_HANDLED;
}

/**
 *  sxgbe_tx_interrupt - TX DMA ISR
 *  @irq: interrupt number.
 *  @dev_id: to pass the net device pointer.
 *  Description: this is the tx dma interrupt service routine.
 */
static irqreturn_t sxgbe_tx_interrupt(int irq, void *dev_id)
{
        int status;
        struct sxgbe_tx_queue *txq = (struct sxgbe_tx_queue *)dev_id;
        struct sxgbe_priv_data *priv = txq->priv_ptr;

        /* get the channel status */
        status = priv->hw->dma->tx_dma_int_status(priv->ioaddr, txq->queue_no,
                                                  &priv->xstats);
        /* check for normal path */
        if (likely((status & handle_tx)))
                napi_schedule(&priv->napi);

        /* check for unrecoverable error */
        if (unlikely((status & tx_hard_error)))
                sxgbe_restart_tx_queue(priv, txq->queue_no);

        /* check for TC configuration change */
        if (unlikely((status & tx_bump_tc) &&
                     (priv->tx_tc != SXGBE_MTL_SFMODE) &&
                     (priv->tx_tc < 512))) {
                /* step of TX TC is 32 till 128, otherwise 64 */
                priv->tx_tc += (priv->tx_tc < 128) ? 32 : 64;
                priv->hw->mtl->set_tx_mtl_mode(priv->ioaddr,
                                               txq->queue_no, priv->tx_tc);
                priv->xstats.tx_threshold = priv->tx_tc;
        }

        return IRQ_HANDLED;
}

/**
 *  sxgbe_rx_interrupt - RX DMA ISR
 *  @irq: interrupt number.
 *  @dev_id: to pass the net device pointer.
 *  Description: this is the rx dma interrupt service routine.
 */
static irqreturn_t sxgbe_rx_interrupt(int irq, void *dev_id)
{
        int status;
        struct sxgbe_rx_queue *rxq = (struct sxgbe_rx_queue *)dev_id;
        struct sxgbe_priv_data *priv = rxq->priv_ptr;

        /* get the channel status */
        status = priv->hw->dma->rx_dma_int_status(priv->ioaddr, rxq->queue_no,
                                                  &priv->xstats);

        if (likely((status & handle_rx) && (napi_schedule_prep(&priv->napi)))) {
                priv->hw->dma->disable_dma_irq(priv->ioaddr, rxq->queue_no);
                __napi_schedule(&priv->napi);
        }

        /* check for TC configuration change */
        if (unlikely((status & rx_bump_tc) &&
                     (priv->rx_tc != SXGBE_MTL_SFMODE) &&
                     (priv->rx_tc < 128))) {
                /* step of TC is 32 */
                priv->rx_tc += 32;
                priv->hw->mtl->set_rx_mtl_mode(priv->ioaddr,
                                               rxq->queue_no, priv->rx_tc);
                priv->xstats.rx_threshold = priv->rx_tc;
        }

        return IRQ_HANDLED;
}

static inline u64 sxgbe_get_stat64(void __iomem *ioaddr, int reg_lo, int reg_hi)
{
        u64 val = readl(ioaddr + reg_lo);

        val |= ((u64)readl(ioaddr + reg_hi)) << 32;

        return val;
}


/*  sxgbe_get_stats64 - entry point to see statistical information of device
 *  @dev : device pointer.
 *  @stats : pointer to hold all the statistical information of device.
 *  Description:
 *  This function is a driver entry point whenever ifconfig command gets
 *  executed to see device statistics. Statistics are number of
 *  bytes sent or received, errors occured etc.
 *  Return value:
 *  This function returns various statistical information of device.
 */
static struct rtnl_link_stats64 *sxgbe_get_stats64(struct net_device *dev,
                                                   struct rtnl_link_stats64 *stats)
{
        struct sxgbe_priv_data *priv = netdev_priv(dev);
        void __iomem *ioaddr = priv->ioaddr;
        u64 count;

        spin_lock(&priv->stats_lock);
        /* Freeze the counter registers before reading value otherwise it may
         * get updated by hardware while we are reading them
         */
        writel(SXGBE_MMC_CTRL_CNT_FRZ, ioaddr + SXGBE_MMC_CTL_REG);

        stats->rx_bytes = sxgbe_get_stat64(ioaddr,
                                           SXGBE_MMC_RXOCTETLO_GCNT_REG,
                                           SXGBE_MMC_RXOCTETHI_GCNT_REG);

        stats->rx_packets = sxgbe_get_stat64(ioaddr,
                                             SXGBE_MMC_RXFRAMELO_GBCNT_REG,
                                             SXGBE_MMC_RXFRAMEHI_GBCNT_REG);

        stats->multicast = sxgbe_get_stat64(ioaddr,
                                            SXGBE_MMC_RXMULTILO_GCNT_REG,
                                            SXGBE_MMC_RXMULTIHI_GCNT_REG);

        stats->rx_crc_errors = sxgbe_get_stat64(ioaddr,
                                                SXGBE_MMC_RXCRCERRLO_REG,
                                                SXGBE_MMC_RXCRCERRHI_REG);

        stats->rx_length_errors = sxgbe_get_stat64(ioaddr,
                                                  SXGBE_MMC_RXLENERRLO_REG,
                                                  SXGBE_MMC_RXLENERRHI_REG);

        stats->rx_missed_errors = sxgbe_get_stat64(ioaddr,
                                                   SXGBE_MMC_RXFIFOOVERFLOWLO_GBCNT_REG,
                                                   SXGBE_MMC_RXFIFOOVERFLOWHI_GBCNT_REG);

        stats->tx_bytes = sxgbe_get_stat64(ioaddr,
                                           SXGBE_MMC_TXOCTETLO_GCNT_REG,
                                           SXGBE_MMC_TXOCTETHI_GCNT_REG);

        count = sxgbe_get_stat64(ioaddr, SXGBE_MMC_TXFRAMELO_GBCNT_REG,
                                 SXGBE_MMC_TXFRAMEHI_GBCNT_REG);

        stats->tx_errors = sxgbe_get_stat64(ioaddr, SXGBE_MMC_TXFRAMELO_GCNT_REG,
                                            SXGBE_MMC_TXFRAMEHI_GCNT_REG);
        stats->tx_errors = count - stats->tx_errors;
        stats->tx_packets = count;
        stats->tx_fifo_errors = sxgbe_get_stat64(ioaddr, SXGBE_MMC_TXUFLWLO_GBCNT_REG,
                                                 SXGBE_MMC_TXUFLWHI_GBCNT_REG);
        writel(0, ioaddr + SXGBE_MMC_CTL_REG);
        spin_unlock(&priv->stats_lock);

        return stats;
}

/*  sxgbe_set_features - entry point to set offload features of the device.
 *  @dev : device pointer.
 *  @features : features which are required to be set.
 *  Description:
 *  This function is a driver entry point and called by Linux kernel whenever
 *  any device features are set or reset by user.
 *  Return value:
 *  This function returns 0 after setting or resetting device features.
 */
static int sxgbe_set_features(struct net_device *dev,
                              netdev_features_t features)
{
        struct sxgbe_priv_data *priv = netdev_priv(dev);
        netdev_features_t changed = dev->features ^ features;

        if (changed & NETIF_F_RXCSUM) {
                if (features & NETIF_F_RXCSUM) {
                        priv->hw->mac->enable_rx_csum(priv->ioaddr);
                        priv->rxcsum_insertion = true;
                } else {
                        priv->hw->mac->disable_rx_csum(priv->ioaddr);
                        priv->rxcsum_insertion = false;
                }
        }

        return 0;
}

/*  sxgbe_change_mtu - entry point to change MTU size for the device.
 *  @dev : device pointer.
 *  @new_mtu : the new MTU size for the device.
 *  Description: the Maximum Transfer Unit (MTU) is used by the network layer
 *  to drive packet transmission. Ethernet has an MTU of 1500 octets
 *  (ETH_DATA_LEN). This value can be changed with ifconfig.
 *  Return value:
 *  0 on success and an appropriate (-)ve integer as defined in errno.h
 *  file on failure.
 */
static int sxgbe_change_mtu(struct net_device *dev, int new_mtu)
{
        /* RFC 791, page 25, "Every internet module must be able to forward
         * a datagram of 68 octets without further fragmentation."
         */
        if (new_mtu < MIN_MTU || (new_mtu > MAX_MTU)) {
                netdev_err(dev, "invalid MTU, MTU should be in between %d and %d\n",
                           MIN_MTU, MAX_MTU);
                return -EINVAL;
        }

        /* Return if the buffer sizes will not change */
        if (dev->mtu == new_mtu)
                return 0;

        dev->mtu = new_mtu;

        if (!netif_running(dev))
                return 0;

        /* Recevice ring buffer size is needed to be set based on MTU. If MTU is
         * changed then reinitilisation of the receive ring buffers need to be
         * done. Hence bring interface down and bring interface back up
         */
        sxgbe_release(dev);
        return sxgbe_open(dev);
}

static void sxgbe_set_umac_addr(void __iomem *ioaddr, unsigned char *addr,
                                unsigned int reg_n)
{
        unsigned long data;

        data = (addr[5] << 8) | addr[4];
        /* For MAC Addr registers se have to set the Address Enable (AE)
         * bit that has no effect on the High Reg 0 where the bit 31 (MO)
         * is RO.
         */
        writel(data | SXGBE_HI_REG_AE, ioaddr + SXGBE_ADDR_HIGH(reg_n));
        data = (addr[3] << 24) | (addr[2] << 16) | (addr[1] << 8) | addr[0];
        writel(data, ioaddr + SXGBE_ADDR_LOW(reg_n));
}

/**
 * sxgbe_set_rx_mode - entry point for setting different receive mode of
 * a device. unicast, multicast addressing
 * @dev : pointer to the device structure
 * Description:
 * This function is a driver entry point which gets called by the kernel
 * whenever different receive mode like unicast, multicast and promiscuous
 * must be enabled/disabled.
 * Return value:
 * void.
 */
static void sxgbe_set_rx_mode(struct net_device *dev)
{
        struct sxgbe_priv_data *priv = netdev_priv(dev);
        void __iomem *ioaddr = (void __iomem *)priv->ioaddr;
        unsigned int value = 0;
        u32 mc_filter[2];
        struct netdev_hw_addr *ha;
        int reg = 1;

        netdev_dbg(dev, "%s: # mcasts %d, # unicast %d\n",
                   __func__, netdev_mc_count(dev), netdev_uc_count(dev));

        if (dev->flags & IFF_PROMISC) {
                value = SXGBE_FRAME_FILTER_PR;

        } else if ((netdev_mc_count(dev) > SXGBE_HASH_TABLE_SIZE) ||
                   (dev->flags & IFF_ALLMULTI)) {
                value = SXGBE_FRAME_FILTER_PM;  /* pass all multi */
                writel(0xffffffff, ioaddr + SXGBE_HASH_HIGH);
                writel(0xffffffff, ioaddr + SXGBE_HASH_LOW);

        } else if (!netdev_mc_empty(dev)) {
                /* Hash filter for multicast */
                value = SXGBE_FRAME_FILTER_HMC;

                memset(mc_filter, 0, sizeof(mc_filter));
                netdev_for_each_mc_addr(ha, dev) {
                        /* The upper 6 bits of the calculated CRC are used to
                         * index the contens of the hash table
                         */
                        int bit_nr = bitrev32(~crc32_le(~0, ha->addr, 6)) >> 26;

                        /* The most significant bit determines the register to
                         * use (H/L) while the other 5 bits determine the bit
                         * within the register.
                         */
                        mc_filter[bit_nr >> 5] |= 1 << (bit_nr & 31);
                }
                writel(mc_filter[0], ioaddr + SXGBE_HASH_LOW);
                writel(mc_filter[1], ioaddr + SXGBE_HASH_HIGH);
        }

        /* Handle multiple unicast addresses (perfect filtering) */
        if (netdev_uc_count(dev) > SXGBE_MAX_PERFECT_ADDRESSES)
                /* Switch to promiscuous mode if more than 16 addrs
                 * are required
                 */
                value |= SXGBE_FRAME_FILTER_PR;
        else {
                netdev_for_each_uc_addr(ha, dev) {
                        sxgbe_set_umac_addr(ioaddr, ha->addr, reg);
                        reg++;
                }
        }
#ifdef FRAME_FILTER_DEBUG
        /* Enable Receive all mode (to debug filtering_fail errors) */
        value |= SXGBE_FRAME_FILTER_RA;
#endif
        writel(value, ioaddr + SXGBE_FRAME_FILTER);

        netdev_dbg(dev, "Filter: 0x%08x\n\tHash: HI 0x%08x, LO 0x%08x\n",
                   readl(ioaddr + SXGBE_FRAME_FILTER),
                   readl(ioaddr + SXGBE_HASH_HIGH),
                   readl(ioaddr + SXGBE_HASH_LOW));
}

/**
 * sxgbe_config - entry point for changing configuration mode passed on by
 * ifconfig
 * @dev : pointer to the device structure
 * @map : pointer to the device mapping structure
 * Description:
 * This function is a driver entry point which gets called by the kernel
 * whenever some device configuration is changed.
 * Return value:
 * This function returns 0 if success and appropriate error otherwise.
 */
static int sxgbe_config(struct net_device *dev, struct ifmap *map)
{
        struct sxgbe_priv_data *priv = netdev_priv(dev);

        /* Can't act on a running interface */
        if (dev->flags & IFF_UP)
                return -EBUSY;

        /* Don't allow changing the I/O address */
        if (map->base_addr != (unsigned long)priv->ioaddr) {
                netdev_warn(dev, "can't change I/O address\n");
                return -EOPNOTSUPP;
        }

        /* Don't allow changing the IRQ */
        if (map->irq != priv->irq) {
                netdev_warn(dev, "not change IRQ number %d\n", priv->irq);
                return -EOPNOTSUPP;
        }

        return 0;
}

#ifdef CONFIG_NET_POLL_CONTROLLER
/**
 * sxgbe_poll_controller - entry point for polling receive by device
 * @dev : pointer to the device structure
 * Description:
 * This function is used by NETCONSOLE and other diagnostic tools
 * to allow network I/O with interrupts disabled.
 * Return value:
 * Void.
 */
static void sxgbe_poll_controller(struct net_device *dev)
{
        struct sxgbe_priv_data *priv = netdev_priv(dev);

        disable_irq(priv->irq);
        sxgbe_rx_interrupt(priv->irq, dev);
        enable_irq(priv->irq);
}
#endif

/*  sxgbe_ioctl - Entry point for the Ioctl
 *  @dev: Device pointer.
 *  @rq: An IOCTL specefic structure, that can contain a pointer to
 *  a proprietary structure used to pass information to the driver.
 *  @cmd: IOCTL command
 *  Description:
 *  Currently it supports the phy_mii_ioctl(...) and HW time stamping.
 */
static int sxgbe_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
        struct sxgbe_priv_data *priv = netdev_priv(dev);
        int ret = -EOPNOTSUPP;

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

        switch (cmd) {
        case SIOCGMIIPHY:
        case SIOCGMIIREG:
        case SIOCSMIIREG:
                if (!priv->phydev)
                        return -EINVAL;
                ret = phy_mii_ioctl(priv->phydev, rq, cmd);
                break;
        default:
                break;
        }

        return ret;
}

static const struct net_device_ops sxgbe_netdev_ops = {
        .ndo_open               = sxgbe_open,
        .ndo_start_xmit         = sxgbe_xmit,
        .ndo_stop               = sxgbe_release,
        .ndo_get_stats64        = sxgbe_get_stats64,
        .ndo_change_mtu         = sxgbe_change_mtu,
        .ndo_set_features       = sxgbe_set_features,
        .ndo_set_rx_mode        = sxgbe_set_rx_mode,
        .ndo_tx_timeout         = sxgbe_tx_timeout,
        .ndo_do_ioctl           = sxgbe_ioctl,
        .ndo_set_config         = sxgbe_config,
#ifdef CONFIG_NET_POLL_CONTROLLER
        .ndo_poll_controller    = sxgbe_poll_controller,
#endif
        .ndo_set_mac_address    = eth_mac_addr,
};

/* Get the hardware ops */
static void sxgbe_get_ops(struct sxgbe_ops * const ops_ptr)
{
        ops_ptr->mac            = sxgbe_get_core_ops();
        ops_ptr->desc           = sxgbe_get_desc_ops();
        ops_ptr->dma            = sxgbe_get_dma_ops();
        ops_ptr->mtl            = sxgbe_get_mtl_ops();

        /* set the MDIO communication Address/Data regisers */
        ops_ptr->mii.addr       = SXGBE_MDIO_SCMD_ADD_REG;
        ops_ptr->mii.data       = SXGBE_MDIO_SCMD_DATA_REG;

        /* Assigning the default link settings
         * no SXGBE defined default values to be set in registers,
         * so assigning as 0 for port and duplex
         */
        ops_ptr->link.port      = 0;
        ops_ptr->link.duplex    = 0;
        ops_ptr->link.speed     = SXGBE_SPEED_10G;
}

/**
 *  sxgbe_hw_init - Init the GMAC device
 *  @priv: driver private structure
 *  Description: this function checks the HW capability
 *  (if supported) and sets the driver's features.
 */
static int sxgbe_hw_init(struct sxgbe_priv_data * const priv)
{
        u32 ctrl_ids;

        priv->hw = kmalloc(sizeof(*priv->hw), GFP_KERNEL);
        if(!priv->hw)
                return -ENOMEM;

        /* get the hardware ops */
        sxgbe_get_ops(priv->hw);

        /* get the controller id */
        ctrl_ids = priv->hw->mac->get_controller_version(priv->ioaddr);
        priv->hw->ctrl_uid = (ctrl_ids & 0x00ff0000) >> 16;
        priv->hw->ctrl_id = (ctrl_ids & 0x000000ff);
        pr_info("user ID: 0x%x, Controller ID: 0x%x\n",
                priv->hw->ctrl_uid, priv->hw->ctrl_id);

        /* get the H/W features */
        if (!sxgbe_get_hw_features(priv))
                pr_info("Hardware features not found\n");

        if (priv->hw_cap.tx_csum_offload)
                pr_info("TX Checksum offload supported\n");

        if (priv->hw_cap.rx_csum_offload)
                pr_info("RX Checksum offload supported\n");

        return 0;
}

/**
 * sxgbe_drv_probe
 * @device: device pointer
 * @plat_dat: platform data pointer
 * @addr: iobase memory address
 * Description: this is the main probe function used to
 * call the alloc_etherdev, allocate the priv structure.
 */
struct sxgbe_priv_data *sxgbe_drv_probe(struct device *device,
                                        struct sxgbe_plat_data *plat_dat,
                                        void __iomem *addr)
{
        struct sxgbe_priv_data *priv;
        struct net_device *ndev;
        int ret;
        u8 queue_num;

        ndev = alloc_etherdev_mqs(sizeof(struct sxgbe_priv_data),
                                  SXGBE_TX_QUEUES, SXGBE_RX_QUEUES);
        if (!ndev)
                return NULL;

        SET_NETDEV_DEV(ndev, device);

        priv = netdev_priv(ndev);
        priv->device = device;
        priv->dev = ndev;

        sxgbe_set_ethtool_ops(ndev);
        priv->plat = plat_dat;
        priv->ioaddr = addr;

        /* Verify driver arguments */
        sxgbe_verify_args();

        /* Init MAC and get the capabilities */
        ret = sxgbe_hw_init(priv);
        if (ret)
                goto error_free_netdev;

        /* allocate memory resources for Descriptor rings */
        ret = txring_mem_alloc(priv);
        if (ret)
                goto error_free_hw;

        ret = rxring_mem_alloc(priv);
        if (ret)
                goto error_free_hw;

        ndev->netdev_ops = &sxgbe_netdev_ops;

        ndev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
                NETIF_F_RXCSUM | NETIF_F_TSO | NETIF_F_TSO6 |
                NETIF_F_GRO;
        ndev->features |= ndev->hw_features | NETIF_F_HIGHDMA;
        ndev->watchdog_timeo = msecs_to_jiffies(TX_TIMEO);

        /* assign filtering support */
        ndev->priv_flags |= IFF_UNICAST_FLT;

        priv->msg_enable = netif_msg_init(debug, default_msg_level);

        /* Enable TCP segmentation offload for all DMA channels */
        if (priv->hw_cap.tcpseg_offload) {
                SXGBE_FOR_EACH_QUEUE(SXGBE_TX_QUEUES, queue_num) {
                        priv->hw->dma->enable_tso(priv->ioaddr, queue_num);
                }
        }

        /* Enable Rx checksum offload */
        if (priv->hw_cap.rx_csum_offload) {
                priv->hw->mac->enable_rx_csum(priv->ioaddr);
                priv->rxcsum_insertion = true;
        }

        /* Initialise pause frame settings */
        priv->rx_pause = 1;
        priv->tx_pause = 1;

        /* Rx Watchdog is available, enable depend on platform data */
        if (!priv->plat->riwt_off) {
                priv->use_riwt = 1;
                pr_info("Enable RX Mitigation via HW Watchdog Timer\n");
        }

        netif_napi_add(ndev, &priv->napi, sxgbe_poll, 64);

        spin_lock_init(&priv->stats_lock);

        priv->sxgbe_clk = clk_get(priv->device, SXGBE_RESOURCE_NAME);
        if (IS_ERR(priv->sxgbe_clk)) {
                netdev_warn(ndev, "%s: warning: cannot get CSR clock\n",
                            __func__);
                goto error_napi_del;
        }

        /* If a specific clk_csr value is passed from the platform
         * this means that the CSR Clock Range selection cannot be
         * changed at run-time and it is fixed. Viceversa the driver'll try to
         * set the MDC clock dynamically according to the csr actual
         * clock input.
         */
        if (!priv->plat->clk_csr)
                sxgbe_clk_csr_set(priv);
        else
                priv->clk_csr = priv->plat->clk_csr;

        /* MDIO bus Registration */
        ret = sxgbe_mdio_register(ndev);
        if (ret < 0) {
                netdev_dbg(ndev, "%s: MDIO bus (id: %d) registration failed\n",
                           __func__, priv->plat->bus_id);
                goto error_clk_put;
        }

        ret = register_netdev(ndev);
        if (ret) {
                pr_err("%s: ERROR %i registering the device\n", __func__, ret);
                goto error_mdio_unregister;
        }

        sxgbe_check_ether_addr(priv);

        return priv;

error_mdio_unregister:
        sxgbe_mdio_unregister(ndev);
error_clk_put:
        clk_put(priv->sxgbe_clk);
error_napi_del:
        netif_napi_del(&priv->napi);
error_free_hw:
        kfree(priv->hw);
error_free_netdev:
        free_netdev(ndev);

        return NULL;
}

/**
 * sxgbe_drv_remove
 * @ndev: net device pointer
 * Description: this function resets the TX/RX processes, disables the MAC RX/TX
 * changes the link status, releases the DMA descriptor rings.
 */
int sxgbe_drv_remove(struct net_device *ndev)
{
        struct sxgbe_priv_data *priv = netdev_priv(ndev);

        netdev_info(ndev, "%s: removing driver\n", __func__);

        priv->hw->dma->stop_rx(priv->ioaddr, SXGBE_RX_QUEUES);
        priv->hw->dma->stop_tx(priv->ioaddr, SXGBE_TX_QUEUES);

        priv->hw->mac->enable_tx(priv->ioaddr, false);
        priv->hw->mac->enable_rx(priv->ioaddr, false);

        unregister_netdev(ndev);

        sxgbe_mdio_unregister(ndev);

        clk_put(priv->sxgbe_clk);

        netif_napi_del(&priv->napi);

        kfree(priv->hw);

        free_netdev(ndev);

        return 0;
}

#ifdef CONFIG_PM
int sxgbe_suspend(struct net_device *ndev)
{
        return 0;
}

int sxgbe_resume(struct net_device *ndev)
{
        return 0;
}

int sxgbe_freeze(struct net_device *ndev)
{
        return -ENOSYS;
}

int sxgbe_restore(struct net_device *ndev)
{
        return -ENOSYS;
}
#endif /* CONFIG_PM */

/* Driver is configured as Platform driver */
static int __init sxgbe_init(void)
{
        int ret;

        ret = sxgbe_register_platform();
        if (ret)
                goto err;
        return 0;
err:
        pr_err("driver registration failed\n");
        return ret;
}

static void __exit sxgbe_exit(void)
{
        sxgbe_unregister_platform();
}

module_init(sxgbe_init);
module_exit(sxgbe_exit);

#ifndef MODULE
static int __init sxgbe_cmdline_opt(char *str)
{
        char *opt;

        if (!str || !*str)
                return -EINVAL;
        while ((opt = strsep(&str, ",")) != NULL) {
                if (!strncmp(opt, "eee_timer:", 6)) {
                        if (kstrtoint(opt + 10, 0, &eee_timer))
                                goto err;
                }
        }
        return 0;

err:
        pr_err("%s: ERROR broken module parameter conversion\n", __func__);
        return -EINVAL;
}

__setup("sxgbeeth=", sxgbe_cmdline_opt);
#endif /* MODULE */



MODULE_DESCRIPTION("SAMSUNG 10G/2.5G/1G Ethernet PLATFORM driver");

MODULE_PARM_DESC(debug, "Message Level (-1: default, 0: no output, 16: all)");
MODULE_PARM_DESC(eee_timer, "EEE-LPI Default LS timer value");

MODULE_AUTHOR("Siva Reddy Kallam <siva.kallam@samsung.com>");
MODULE_AUTHOR("ByungHo An <bh74.an@samsung.com>");
MODULE_AUTHOR("Girish K S <ks.giri@samsung.com>");
MODULE_AUTHOR("Vipul Pandya <vipul.pandya@samsung.com>");

MODULE_LICENSE("GPL");