/* Synopsys DesignWare Core Enterprise Ethernet (XLGMAC) Driver
 *
 * Copyright (c) 2017 Synopsys, Inc. (www.synopsys.com)
 *
 * This program is dual-licensed; you may select either version 2 of
 * the GNU General Public License ("GPL") or BSD license ("BSD").
 *
 * This Synopsys DWC XLGMAC software driver and associated documentation
 * (hereinafter the "Software") is an unsupported proprietary work of
 * Synopsys, Inc. unless otherwise expressly agreed to in writing between
 * Synopsys and you. The Software IS NOT an item of Licensed Software or a
 * Licensed Product under any End User Software License Agreement or
 * Agreement for Licensed Products with Synopsys or any supplement thereto.
 * Synopsys is a registered trademark of Synopsys, Inc. Other names included
 * in the SOFTWARE may be the trademarks of their respective owners.
 */

#include <linux/netdevice.h>
#include <linux/tcp.h>
#include <linux/interrupt.h>

#include "dwc-xlgmac.h"
#include "dwc-xlgmac-reg.h"

static int xlgmac_one_poll(struct napi_struct *, int);
static int xlgmac_all_poll(struct napi_struct *, int);

static inline unsigned int xlgmac_tx_avail_desc(struct xlgmac_ring *ring)
{
        return (ring->dma_desc_count - (ring->cur - ring->dirty));
}

static inline unsigned int xlgmac_rx_dirty_desc(struct xlgmac_ring *ring)
{
        return (ring->cur - ring->dirty);
}

static int xlgmac_maybe_stop_tx_queue(
                        struct xlgmac_channel *channel,
                        struct xlgmac_ring *ring,
                        unsigned int count)
{
        struct xlgmac_pdata *pdata = channel->pdata;

        if (count > xlgmac_tx_avail_desc(ring)) {
                netif_info(pdata, drv, pdata->netdev,
                           "Tx queue stopped, not enough descriptors available\n");
                netif_stop_subqueue(pdata->netdev, channel->queue_index);
                ring->tx.queue_stopped = 1;

                /* If we haven't notified the hardware because of xmit_more
                 * support, tell it now
                 */
                if (ring->tx.xmit_more)
                        pdata->hw_ops.tx_start_xmit(channel, ring);

                return NETDEV_TX_BUSY;
        }

        return 0;
}

static void xlgmac_prep_vlan(struct sk_buff *skb,
                             struct xlgmac_pkt_info *pkt_info)
{
        if (skb_vlan_tag_present(skb))
                pkt_info->vlan_ctag = skb_vlan_tag_get(skb);
}

static int xlgmac_prep_tso(struct sk_buff *skb,
                           struct xlgmac_pkt_info *pkt_info)
{
        int ret;

        if (!XLGMAC_GET_REG_BITS(pkt_info->attributes,
                                 TX_PACKET_ATTRIBUTES_TSO_ENABLE_POS,
                                 TX_PACKET_ATTRIBUTES_TSO_ENABLE_LEN))
                return 0;

        ret = skb_cow_head(skb, 0);
        if (ret)
                return ret;

        pkt_info->header_len = skb_tcp_all_headers(skb);
        pkt_info->tcp_header_len = tcp_hdrlen(skb);
        pkt_info->tcp_payload_len = skb->len - pkt_info->header_len;
        pkt_info->mss = skb_shinfo(skb)->gso_size;

        XLGMAC_PR("header_len=%u\n", pkt_info->header_len);
        XLGMAC_PR("tcp_header_len=%u, tcp_payload_len=%u\n",
                  pkt_info->tcp_header_len, pkt_info->tcp_payload_len);
        XLGMAC_PR("mss=%u\n", pkt_info->mss);

        /* Update the number of packets that will ultimately be transmitted
         * along with the extra bytes for each extra packet
         */
        pkt_info->tx_packets = skb_shinfo(skb)->gso_segs;
        pkt_info->tx_bytes += (pkt_info->tx_packets - 1) * pkt_info->header_len;

        return 0;
}

static int xlgmac_is_tso(struct sk_buff *skb)
{
        if (skb->ip_summed != CHECKSUM_PARTIAL)
                return 0;

        if (!skb_is_gso(skb))
                return 0;

        return 1;
}

static void xlgmac_prep_tx_pkt(struct xlgmac_pdata *pdata,
                               struct xlgmac_ring *ring,
                               struct sk_buff *skb,
                               struct xlgmac_pkt_info *pkt_info)
{
        skb_frag_t *frag;
        unsigned int context_desc;
        unsigned int len;
        unsigned int i;

        pkt_info->skb = skb;

        context_desc = 0;
        pkt_info->desc_count = 0;

        pkt_info->tx_packets = 1;
        pkt_info->tx_bytes = skb->len;

        if (xlgmac_is_tso(skb)) {
                /* TSO requires an extra descriptor if mss is different */
                if (skb_shinfo(skb)->gso_size != ring->tx.cur_mss) {
                        context_desc = 1;
                        pkt_info->desc_count++;
                }

                /* TSO requires an extra descriptor for TSO header */
                pkt_info->desc_count++;

                pkt_info->attributes = XLGMAC_SET_REG_BITS(
                                        pkt_info->attributes,
                                        TX_PACKET_ATTRIBUTES_TSO_ENABLE_POS,
                                        TX_PACKET_ATTRIBUTES_TSO_ENABLE_LEN,
                                        1);
                pkt_info->attributes = XLGMAC_SET_REG_BITS(
                                        pkt_info->attributes,
                                        TX_PACKET_ATTRIBUTES_CSUM_ENABLE_POS,
                                        TX_PACKET_ATTRIBUTES_CSUM_ENABLE_LEN,
                                        1);
        } else if (skb->ip_summed == CHECKSUM_PARTIAL)
                pkt_info->attributes = XLGMAC_SET_REG_BITS(
                                        pkt_info->attributes,
                                        TX_PACKET_ATTRIBUTES_CSUM_ENABLE_POS,
                                        TX_PACKET_ATTRIBUTES_CSUM_ENABLE_LEN,
                                        1);

        if (skb_vlan_tag_present(skb)) {
                /* VLAN requires an extra descriptor if tag is different */
                if (skb_vlan_tag_get(skb) != ring->tx.cur_vlan_ctag)
                        /* We can share with the TSO context descriptor */
                        if (!context_desc) {
                                context_desc = 1;
                                pkt_info->desc_count++;
                        }

                pkt_info->attributes = XLGMAC_SET_REG_BITS(
                                        pkt_info->attributes,
                                        TX_PACKET_ATTRIBUTES_VLAN_CTAG_POS,
                                        TX_PACKET_ATTRIBUTES_VLAN_CTAG_LEN,
                                        1);
        }

        for (len = skb_headlen(skb); len;) {
                pkt_info->desc_count++;
                len -= min_t(unsigned int, len, XLGMAC_TX_MAX_BUF_SIZE);
        }

        for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
                frag = &skb_shinfo(skb)->frags[i];
                for (len = skb_frag_size(frag); len; ) {
                        pkt_info->desc_count++;
                        len -= min_t(unsigned int, len, XLGMAC_TX_MAX_BUF_SIZE);
                }
        }
}

static int xlgmac_calc_rx_buf_size(struct net_device *netdev, unsigned int mtu)
{
        unsigned int rx_buf_size;

        if (mtu > XLGMAC_JUMBO_PACKET_MTU) {
                netdev_alert(netdev, "MTU exceeds maximum supported value\n");
                return -EINVAL;
        }

        rx_buf_size = mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN;
        rx_buf_size = clamp_val(rx_buf_size, XLGMAC_RX_MIN_BUF_SIZE, PAGE_SIZE);

        rx_buf_size = (rx_buf_size + XLGMAC_RX_BUF_ALIGN - 1) &
                      ~(XLGMAC_RX_BUF_ALIGN - 1);

        return rx_buf_size;
}

static void xlgmac_enable_rx_tx_ints(struct xlgmac_pdata *pdata)
{
        struct xlgmac_hw_ops *hw_ops = &pdata->hw_ops;
        struct xlgmac_channel *channel;
        enum xlgmac_int int_id;
        unsigned int i;

        channel = pdata->channel_head;
        for (i = 0; i < pdata->channel_count; i++, channel++) {
                if (channel->tx_ring && channel->rx_ring)
                        int_id = XLGMAC_INT_DMA_CH_SR_TI_RI;
                else if (channel->tx_ring)
                        int_id = XLGMAC_INT_DMA_CH_SR_TI;
                else if (channel->rx_ring)
                        int_id = XLGMAC_INT_DMA_CH_SR_RI;
                else
                        continue;

                hw_ops->enable_int(channel, int_id);
        }
}

static void xlgmac_disable_rx_tx_ints(struct xlgmac_pdata *pdata)
{
        struct xlgmac_hw_ops *hw_ops = &pdata->hw_ops;
        struct xlgmac_channel *channel;
        enum xlgmac_int int_id;
        unsigned int i;

        channel = pdata->channel_head;
        for (i = 0; i < pdata->channel_count; i++, channel++) {
                if (channel->tx_ring && channel->rx_ring)
                        int_id = XLGMAC_INT_DMA_CH_SR_TI_RI;
                else if (channel->tx_ring)
                        int_id = XLGMAC_INT_DMA_CH_SR_TI;
                else if (channel->rx_ring)
                        int_id = XLGMAC_INT_DMA_CH_SR_RI;
                else
                        continue;

                hw_ops->disable_int(channel, int_id);
        }
}

static irqreturn_t xlgmac_isr(int irq, void *data)
{
        unsigned int dma_isr, dma_ch_isr, mac_isr;
        struct xlgmac_pdata *pdata = data;
        struct xlgmac_channel *channel;
        struct xlgmac_hw_ops *hw_ops;
        unsigned int i, ti, ri;

        hw_ops = &pdata->hw_ops;

        /* The DMA interrupt status register also reports MAC and MTL
         * interrupts. So for polling mode, we just need to check for
         * this register to be non-zero
         */
        dma_isr = readl(pdata->mac_regs + DMA_ISR);
        if (!dma_isr)
                return IRQ_HANDLED;

        netif_dbg(pdata, intr, pdata->netdev, "DMA_ISR=%#010x\n", dma_isr);

        for (i = 0; i < pdata->channel_count; i++) {
                if (!(dma_isr & (1 << i)))
                        continue;

                channel = pdata->channel_head + i;

                dma_ch_isr = readl(XLGMAC_DMA_REG(channel, DMA_CH_SR));
                netif_dbg(pdata, intr, pdata->netdev, "DMA_CH%u_ISR=%#010x\n",
                          i, dma_ch_isr);

                /* The TI or RI interrupt bits may still be set even if using
                 * per channel DMA interrupts. Check to be sure those are not
                 * enabled before using the private data napi structure.
                 */
                ti = XLGMAC_GET_REG_BITS(dma_ch_isr, DMA_CH_SR_TI_POS,
                                         DMA_CH_SR_TI_LEN);
                ri = XLGMAC_GET_REG_BITS(dma_ch_isr, DMA_CH_SR_RI_POS,
                                         DMA_CH_SR_RI_LEN);
                if (!pdata->per_channel_irq && (ti || ri)) {
                        if (napi_schedule_prep(&pdata->napi)) {
                                /* Disable Tx and Rx interrupts */
                                xlgmac_disable_rx_tx_ints(pdata);

                                pdata->stats.napi_poll_isr++;
                                /* Turn on polling */
                                __napi_schedule_irqoff(&pdata->napi);
                        }
                }

                if (XLGMAC_GET_REG_BITS(dma_ch_isr, DMA_CH_SR_TPS_POS,
                                        DMA_CH_SR_TPS_LEN))
                        pdata->stats.tx_process_stopped++;

                if (XLGMAC_GET_REG_BITS(dma_ch_isr, DMA_CH_SR_RPS_POS,
                                        DMA_CH_SR_RPS_LEN))
                        pdata->stats.rx_process_stopped++;

                if (XLGMAC_GET_REG_BITS(dma_ch_isr, DMA_CH_SR_TBU_POS,
                                        DMA_CH_SR_TBU_LEN))
                        pdata->stats.tx_buffer_unavailable++;

                if (XLGMAC_GET_REG_BITS(dma_ch_isr, DMA_CH_SR_RBU_POS,
                                        DMA_CH_SR_RBU_LEN))
                        pdata->stats.rx_buffer_unavailable++;

                /* Restart the device on a Fatal Bus Error */
                if (XLGMAC_GET_REG_BITS(dma_ch_isr, DMA_CH_SR_FBE_POS,
                                        DMA_CH_SR_FBE_LEN)) {
                        pdata->stats.fatal_bus_error++;
                        schedule_work(&pdata->restart_work);
                }

                /* Clear all interrupt signals */
                writel(dma_ch_isr, XLGMAC_DMA_REG(channel, DMA_CH_SR));
        }

        if (XLGMAC_GET_REG_BITS(dma_isr, DMA_ISR_MACIS_POS,
                                DMA_ISR_MACIS_LEN)) {
                mac_isr = readl(pdata->mac_regs + MAC_ISR);

                if (XLGMAC_GET_REG_BITS(mac_isr, MAC_ISR_MMCTXIS_POS,
                                        MAC_ISR_MMCTXIS_LEN))
                        hw_ops->tx_mmc_int(pdata);

                if (XLGMAC_GET_REG_BITS(mac_isr, MAC_ISR_MMCRXIS_POS,
                                        MAC_ISR_MMCRXIS_LEN))
                        hw_ops->rx_mmc_int(pdata);
        }

        return IRQ_HANDLED;
}

static irqreturn_t xlgmac_dma_isr(int irq, void *data)
{
        struct xlgmac_channel *channel = data;

        /* Per channel DMA interrupts are enabled, so we use the per
         * channel napi structure and not the private data napi structure
         */
        if (napi_schedule_prep(&channel->napi)) {
                /* Disable Tx and Rx interrupts */
                disable_irq_nosync(channel->dma_irq);

                /* Turn on polling */
                __napi_schedule_irqoff(&channel->napi);
        }

        return IRQ_HANDLED;
}

static void xlgmac_tx_timer(struct timer_list *t)
{
        struct xlgmac_channel *channel = timer_container_of(channel, t,
                                                            tx_timer);
        struct xlgmac_pdata *pdata = channel->pdata;
        struct napi_struct *napi;

        napi = (pdata->per_channel_irq) ? &channel->napi : &pdata->napi;

        if (napi_schedule_prep(napi)) {
                /* Disable Tx and Rx interrupts */
                if (pdata->per_channel_irq)
                        disable_irq_nosync(channel->dma_irq);
                else
                        xlgmac_disable_rx_tx_ints(pdata);

                pdata->stats.napi_poll_txtimer++;
                /* Turn on polling */
                __napi_schedule(napi);
        }

        channel->tx_timer_active = 0;
}

static void xlgmac_init_timers(struct xlgmac_pdata *pdata)
{
        struct xlgmac_channel *channel;
        unsigned int i;

        channel = pdata->channel_head;
        for (i = 0; i < pdata->channel_count; i++, channel++) {
                if (!channel->tx_ring)
                        break;

                timer_setup(&channel->tx_timer, xlgmac_tx_timer, 0);
        }
}

static void xlgmac_stop_timers(struct xlgmac_pdata *pdata)
{
        struct xlgmac_channel *channel;
        unsigned int i;

        channel = pdata->channel_head;
        for (i = 0; i < pdata->channel_count; i++, channel++) {
                if (!channel->tx_ring)
                        break;

                timer_delete_sync(&channel->tx_timer);
        }
}

static void xlgmac_napi_enable(struct xlgmac_pdata *pdata, unsigned int add)
{
        struct xlgmac_channel *channel;
        unsigned int i;

        if (pdata->per_channel_irq) {
                channel = pdata->channel_head;
                for (i = 0; i < pdata->channel_count; i++, channel++) {
                        if (add)
                                netif_napi_add(pdata->netdev, &channel->napi,
                                               xlgmac_one_poll);

                        napi_enable(&channel->napi);
                }
        } else {
                if (add)
                        netif_napi_add(pdata->netdev, &pdata->napi,
                                       xlgmac_all_poll);

                napi_enable(&pdata->napi);
        }
}

static void xlgmac_napi_disable(struct xlgmac_pdata *pdata, unsigned int del)
{
        struct xlgmac_channel *channel;
        unsigned int i;

        if (pdata->per_channel_irq) {
                channel = pdata->channel_head;
                for (i = 0; i < pdata->channel_count; i++, channel++) {
                        napi_disable(&channel->napi);

                        if (del)
                                netif_napi_del(&channel->napi);
                }
        } else {
                napi_disable(&pdata->napi);

                if (del)
                        netif_napi_del(&pdata->napi);
        }
}

static int xlgmac_request_irqs(struct xlgmac_pdata *pdata)
{
        struct net_device *netdev = pdata->netdev;
        struct xlgmac_channel *channel;
        unsigned int i;
        int ret;

        ret = devm_request_irq(pdata->dev, pdata->dev_irq, xlgmac_isr,
                               IRQF_SHARED, netdev->name, pdata);
        if (ret) {
                netdev_alert(netdev, "error requesting irq %d\n",
                             pdata->dev_irq);
                return ret;
        }

        if (!pdata->per_channel_irq)
                return 0;

        channel = pdata->channel_head;
        for (i = 0; i < pdata->channel_count; i++, channel++) {
                snprintf(channel->dma_irq_name,
                         sizeof(channel->dma_irq_name) - 1,
                         "%s-TxRx-%u", netdev_name(netdev),
                         channel->queue_index);

                ret = devm_request_irq(pdata->dev, channel->dma_irq,
                                       xlgmac_dma_isr, 0,
                                       channel->dma_irq_name, channel);
                if (ret) {
                        netdev_alert(netdev, "error requesting irq %d\n",
                                     channel->dma_irq);
                        goto err_irq;
                }
        }

        return 0;

err_irq:
        /* Using an unsigned int, 'i' will go to UINT_MAX and exit */
        for (i--, channel--; i < pdata->channel_count; i--, channel--)
                devm_free_irq(pdata->dev, channel->dma_irq, channel);

        devm_free_irq(pdata->dev, pdata->dev_irq, pdata);

        return ret;
}

static void xlgmac_free_irqs(struct xlgmac_pdata *pdata)
{
        struct xlgmac_channel *channel;
        unsigned int i;

        devm_free_irq(pdata->dev, pdata->dev_irq, pdata);

        if (!pdata->per_channel_irq)
                return;

        channel = pdata->channel_head;
        for (i = 0; i < pdata->channel_count; i++, channel++)
                devm_free_irq(pdata->dev, channel->dma_irq, channel);
}

static void xlgmac_free_tx_data(struct xlgmac_pdata *pdata)
{
        struct xlgmac_desc_ops *desc_ops = &pdata->desc_ops;
        struct xlgmac_desc_data *desc_data;
        struct xlgmac_channel *channel;
        struct xlgmac_ring *ring;
        unsigned int i, j;

        channel = pdata->channel_head;
        for (i = 0; i < pdata->channel_count; i++, channel++) {
                ring = channel->tx_ring;
                if (!ring)
                        break;

                for (j = 0; j < ring->dma_desc_count; j++) {
                        desc_data = XLGMAC_GET_DESC_DATA(ring, j);
                        desc_ops->unmap_desc_data(pdata, desc_data);
                }
        }
}

static void xlgmac_free_rx_data(struct xlgmac_pdata *pdata)
{
        struct xlgmac_desc_ops *desc_ops = &pdata->desc_ops;
        struct xlgmac_desc_data *desc_data;
        struct xlgmac_channel *channel;
        struct xlgmac_ring *ring;
        unsigned int i, j;

        channel = pdata->channel_head;
        for (i = 0; i < pdata->channel_count; i++, channel++) {
                ring = channel->rx_ring;
                if (!ring)
                        break;

                for (j = 0; j < ring->dma_desc_count; j++) {
                        desc_data = XLGMAC_GET_DESC_DATA(ring, j);
                        desc_ops->unmap_desc_data(pdata, desc_data);
                }
        }
}

static int xlgmac_start(struct xlgmac_pdata *pdata)
{
        struct xlgmac_hw_ops *hw_ops = &pdata->hw_ops;
        struct net_device *netdev = pdata->netdev;
        int ret;

        hw_ops->init(pdata);
        xlgmac_napi_enable(pdata, 1);

        ret = xlgmac_request_irqs(pdata);
        if (ret)
                goto err_napi;

        hw_ops->enable_tx(pdata);
        hw_ops->enable_rx(pdata);
        netif_tx_start_all_queues(netdev);

        return 0;

err_napi:
        xlgmac_napi_disable(pdata, 1);
        hw_ops->exit(pdata);

        return ret;
}

static void xlgmac_stop(struct xlgmac_pdata *pdata)
{
        struct xlgmac_hw_ops *hw_ops = &pdata->hw_ops;
        struct net_device *netdev = pdata->netdev;
        struct xlgmac_channel *channel;
        struct netdev_queue *txq;
        unsigned int i;

        netif_tx_stop_all_queues(netdev);
        xlgmac_stop_timers(pdata);
        hw_ops->disable_tx(pdata);
        hw_ops->disable_rx(pdata);
        xlgmac_free_irqs(pdata);
        xlgmac_napi_disable(pdata, 1);
        hw_ops->exit(pdata);

        channel = pdata->channel_head;
        for (i = 0; i < pdata->channel_count; i++, channel++) {
                if (!channel->tx_ring)
                        continue;

                txq = netdev_get_tx_queue(netdev, channel->queue_index);
                netdev_tx_reset_queue(txq);
        }
}

static void xlgmac_restart_dev(struct xlgmac_pdata *pdata)
{
        /* If not running, "restart" will happen on open */
        if (!netif_running(pdata->netdev))
                return;

        xlgmac_stop(pdata);

        xlgmac_free_tx_data(pdata);
        xlgmac_free_rx_data(pdata);

        xlgmac_start(pdata);
}

static void xlgmac_restart(struct work_struct *work)
{
        struct xlgmac_pdata *pdata = container_of(work,
                                                   struct xlgmac_pdata,
                                                   restart_work);

        rtnl_lock();

        xlgmac_restart_dev(pdata);

        rtnl_unlock();
}

static int xlgmac_open(struct net_device *netdev)
{
        struct xlgmac_pdata *pdata = netdev_priv(netdev);
        struct xlgmac_desc_ops *desc_ops;
        int ret;

        desc_ops = &pdata->desc_ops;

        /* TODO: Initialize the phy */

        /* Calculate the Rx buffer size before allocating rings */
        ret = xlgmac_calc_rx_buf_size(netdev, netdev->mtu);
        if (ret < 0)
                return ret;
        pdata->rx_buf_size = ret;

        /* Allocate the channels and rings */
        ret = desc_ops->alloc_channels_and_rings(pdata);
        if (ret)
                return ret;

        INIT_WORK(&pdata->restart_work, xlgmac_restart);
        xlgmac_init_timers(pdata);

        ret = xlgmac_start(pdata);
        if (ret)
                goto err_channels_and_rings;

        return 0;

err_channels_and_rings:
        desc_ops->free_channels_and_rings(pdata);

        return ret;
}

static int xlgmac_close(struct net_device *netdev)
{
        struct xlgmac_pdata *pdata = netdev_priv(netdev);
        struct xlgmac_desc_ops *desc_ops;

        desc_ops = &pdata->desc_ops;

        /* Stop the device */
        xlgmac_stop(pdata);

        /* Free the channels and rings */
        desc_ops->free_channels_and_rings(pdata);

        return 0;
}

static void xlgmac_tx_timeout(struct net_device *netdev, unsigned int txqueue)
{
        struct xlgmac_pdata *pdata = netdev_priv(netdev);

        netdev_warn(netdev, "tx timeout, device restarting\n");
        schedule_work(&pdata->restart_work);
}

static netdev_tx_t xlgmac_xmit(struct sk_buff *skb, struct net_device *netdev)
{
        struct xlgmac_pdata *pdata = netdev_priv(netdev);
        struct xlgmac_pkt_info *tx_pkt_info;
        struct xlgmac_desc_ops *desc_ops;
        struct xlgmac_channel *channel;
        struct xlgmac_hw_ops *hw_ops;
        struct netdev_queue *txq;
        struct xlgmac_ring *ring;
        int ret;

        desc_ops = &pdata->desc_ops;
        hw_ops = &pdata->hw_ops;

        XLGMAC_PR("skb->len = %d\n", skb->len);

        channel = pdata->channel_head + skb->queue_mapping;
        txq = netdev_get_tx_queue(netdev, channel->queue_index);
        ring = channel->tx_ring;
        tx_pkt_info = &ring->pkt_info;

        if (skb->len == 0) {
                netif_err(pdata, tx_err, netdev,
                          "empty skb received from stack\n");
                dev_kfree_skb_any(skb);
                return NETDEV_TX_OK;
        }

        /* Prepare preliminary packet info for TX */
        memset(tx_pkt_info, 0, sizeof(*tx_pkt_info));
        xlgmac_prep_tx_pkt(pdata, ring, skb, tx_pkt_info);

        /* Check that there are enough descriptors available */
        ret = xlgmac_maybe_stop_tx_queue(channel, ring,
                                         tx_pkt_info->desc_count);
        if (ret)
                return ret;

        ret = xlgmac_prep_tso(skb, tx_pkt_info);
        if (ret) {
                netif_err(pdata, tx_err, netdev,
                          "error processing TSO packet\n");
                dev_kfree_skb_any(skb);
                return ret;
        }
        xlgmac_prep_vlan(skb, tx_pkt_info);

        if (!desc_ops->map_tx_skb(channel, skb)) {
                dev_kfree_skb_any(skb);
                return NETDEV_TX_OK;
        }

        /* Report on the actual number of bytes (to be) sent */
        netdev_tx_sent_queue(txq, tx_pkt_info->tx_bytes);

        /* Configure required descriptor fields for transmission */
        hw_ops->dev_xmit(channel);

        if (netif_msg_pktdata(pdata))
                xlgmac_print_pkt(netdev, skb, true);

        /* Stop the queue in advance if there may not be enough descriptors */
        xlgmac_maybe_stop_tx_queue(channel, ring, XLGMAC_TX_MAX_DESC_NR);

        return NETDEV_TX_OK;
}

static void xlgmac_get_stats64(struct net_device *netdev,
                               struct rtnl_link_stats64 *s)
{
        struct xlgmac_pdata *pdata = netdev_priv(netdev);
        struct xlgmac_stats *pstats = &pdata->stats;

        pdata->hw_ops.read_mmc_stats(pdata);

        s->rx_packets = pstats->rxframecount_gb;
        s->rx_bytes = pstats->rxoctetcount_gb;
        s->rx_errors = pstats->rxframecount_gb -
                       pstats->rxbroadcastframes_g -
                       pstats->rxmulticastframes_g -
                       pstats->rxunicastframes_g;
        s->multicast = pstats->rxmulticastframes_g;
        s->rx_length_errors = pstats->rxlengtherror;
        s->rx_crc_errors = pstats->rxcrcerror;
        s->rx_fifo_errors = pstats->rxfifooverflow;

        s->tx_packets = pstats->txframecount_gb;
        s->tx_bytes = pstats->txoctetcount_gb;
        s->tx_errors = pstats->txframecount_gb - pstats->txframecount_g;
        s->tx_dropped = netdev->stats.tx_dropped;
}

static int xlgmac_set_mac_address(struct net_device *netdev, void *addr)
{
        struct xlgmac_pdata *pdata = netdev_priv(netdev);
        struct xlgmac_hw_ops *hw_ops = &pdata->hw_ops;
        struct sockaddr *saddr = addr;

        if (!is_valid_ether_addr(saddr->sa_data))
                return -EADDRNOTAVAIL;

        eth_hw_addr_set(netdev, saddr->sa_data);

        hw_ops->set_mac_address(pdata, netdev->dev_addr);

        return 0;
}

static int xlgmac_ioctl(struct net_device *netdev,
                        struct ifreq *ifreq, int cmd)
{
        if (!netif_running(netdev))
                return -ENODEV;

        return 0;
}

static int xlgmac_change_mtu(struct net_device *netdev, int mtu)
{
        struct xlgmac_pdata *pdata = netdev_priv(netdev);
        int ret;

        ret = xlgmac_calc_rx_buf_size(netdev, mtu);
        if (ret < 0)
                return ret;

        pdata->rx_buf_size = ret;
        WRITE_ONCE(netdev->mtu, mtu);

        xlgmac_restart_dev(pdata);

        return 0;
}

static int xlgmac_vlan_rx_add_vid(struct net_device *netdev,
                                  __be16 proto,
                                  u16 vid)
{
        struct xlgmac_pdata *pdata = netdev_priv(netdev);
        struct xlgmac_hw_ops *hw_ops = &pdata->hw_ops;

        set_bit(vid, pdata->active_vlans);
        hw_ops->update_vlan_hash_table(pdata);

        return 0;
}

static int xlgmac_vlan_rx_kill_vid(struct net_device *netdev,
                                   __be16 proto,
                                   u16 vid)
{
        struct xlgmac_pdata *pdata = netdev_priv(netdev);
        struct xlgmac_hw_ops *hw_ops = &pdata->hw_ops;

        clear_bit(vid, pdata->active_vlans);
        hw_ops->update_vlan_hash_table(pdata);

        return 0;
}

#ifdef CONFIG_NET_POLL_CONTROLLER
static void xlgmac_poll_controller(struct net_device *netdev)
{
        struct xlgmac_pdata *pdata = netdev_priv(netdev);
        struct xlgmac_channel *channel;
        unsigned int i;

        if (pdata->per_channel_irq) {
                channel = pdata->channel_head;
                for (i = 0; i < pdata->channel_count; i++, channel++)
                        xlgmac_dma_isr(channel->dma_irq, channel);
        } else {
                disable_irq(pdata->dev_irq);
                xlgmac_isr(pdata->dev_irq, pdata);
                enable_irq(pdata->dev_irq);
        }
}
#endif /* CONFIG_NET_POLL_CONTROLLER */

static int xlgmac_set_features(struct net_device *netdev,
                               netdev_features_t features)
{
        netdev_features_t rxhash, rxcsum, rxvlan, rxvlan_filter;
        struct xlgmac_pdata *pdata = netdev_priv(netdev);
        struct xlgmac_hw_ops *hw_ops = &pdata->hw_ops;
        int ret = 0;

        rxhash = pdata->netdev_features & NETIF_F_RXHASH;
        rxcsum = pdata->netdev_features & NETIF_F_RXCSUM;
        rxvlan = pdata->netdev_features & NETIF_F_HW_VLAN_CTAG_RX;
        rxvlan_filter = pdata->netdev_features & NETIF_F_HW_VLAN_CTAG_FILTER;

        if ((features & NETIF_F_RXHASH) && !rxhash)
                ret = hw_ops->enable_rss(pdata);
        else if (!(features & NETIF_F_RXHASH) && rxhash)
                ret = hw_ops->disable_rss(pdata);
        if (ret)
                return ret;

        if ((features & NETIF_F_RXCSUM) && !rxcsum)
                hw_ops->enable_rx_csum(pdata);
        else if (!(features & NETIF_F_RXCSUM) && rxcsum)
                hw_ops->disable_rx_csum(pdata);

        if ((features & NETIF_F_HW_VLAN_CTAG_RX) && !rxvlan)
                hw_ops->enable_rx_vlan_stripping(pdata);
        else if (!(features & NETIF_F_HW_VLAN_CTAG_RX) && rxvlan)
                hw_ops->disable_rx_vlan_stripping(pdata);

        if ((features & NETIF_F_HW_VLAN_CTAG_FILTER) && !rxvlan_filter)
                hw_ops->enable_rx_vlan_filtering(pdata);
        else if (!(features & NETIF_F_HW_VLAN_CTAG_FILTER) && rxvlan_filter)
                hw_ops->disable_rx_vlan_filtering(pdata);

        pdata->netdev_features = features;

        return 0;
}

static void xlgmac_set_rx_mode(struct net_device *netdev)
{
        struct xlgmac_pdata *pdata = netdev_priv(netdev);
        struct xlgmac_hw_ops *hw_ops = &pdata->hw_ops;

        hw_ops->config_rx_mode(pdata);
}

static const struct net_device_ops xlgmac_netdev_ops = {
        .ndo_open               = xlgmac_open,
        .ndo_stop               = xlgmac_close,
        .ndo_start_xmit         = xlgmac_xmit,
        .ndo_tx_timeout         = xlgmac_tx_timeout,
        .ndo_get_stats64        = xlgmac_get_stats64,
        .ndo_change_mtu         = xlgmac_change_mtu,
        .ndo_set_mac_address    = xlgmac_set_mac_address,
        .ndo_validate_addr      = eth_validate_addr,
        .ndo_eth_ioctl          = xlgmac_ioctl,
        .ndo_vlan_rx_add_vid    = xlgmac_vlan_rx_add_vid,
        .ndo_vlan_rx_kill_vid   = xlgmac_vlan_rx_kill_vid,
#ifdef CONFIG_NET_POLL_CONTROLLER
        .ndo_poll_controller    = xlgmac_poll_controller,
#endif
        .ndo_set_features       = xlgmac_set_features,
        .ndo_set_rx_mode        = xlgmac_set_rx_mode,
};

const struct net_device_ops *xlgmac_get_netdev_ops(void)
{
        return &xlgmac_netdev_ops;
}

static void xlgmac_rx_refresh(struct xlgmac_channel *channel)
{
        struct xlgmac_pdata *pdata = channel->pdata;
        struct xlgmac_ring *ring = channel->rx_ring;
        struct xlgmac_desc_data *desc_data;
        struct xlgmac_desc_ops *desc_ops;
        struct xlgmac_hw_ops *hw_ops;

        desc_ops = &pdata->desc_ops;
        hw_ops = &pdata->hw_ops;

        while (ring->dirty != ring->cur) {
                desc_data = XLGMAC_GET_DESC_DATA(ring, ring->dirty);

                /* Reset desc_data values */
                desc_ops->unmap_desc_data(pdata, desc_data);

                if (desc_ops->map_rx_buffer(pdata, ring, desc_data))
                        break;

                hw_ops->rx_desc_reset(pdata, desc_data, ring->dirty);

                ring->dirty++;
        }

        /* Make sure everything is written before the register write */
        wmb();

        /* Update the Rx Tail Pointer Register with address of
         * the last cleaned entry
         */
        desc_data = XLGMAC_GET_DESC_DATA(ring, ring->dirty - 1);
        writel(lower_32_bits(desc_data->dma_desc_addr),
               XLGMAC_DMA_REG(channel, DMA_CH_RDTR_LO));
}

static struct sk_buff *xlgmac_create_skb(struct xlgmac_pdata *pdata,
                                         struct napi_struct *napi,
                                         struct xlgmac_desc_data *desc_data,
                                         unsigned int len)
{
        unsigned int copy_len;
        struct sk_buff *skb;
        u8 *packet;

        skb = napi_alloc_skb(napi, desc_data->rx.hdr.dma_len);
        if (!skb)
                return NULL;

        /* Start with the header buffer which may contain just the header
         * or the header plus data
         */
        dma_sync_single_range_for_cpu(pdata->dev, desc_data->rx.hdr.dma_base,
                                      desc_data->rx.hdr.dma_off,
                                      desc_data->rx.hdr.dma_len,
                                      DMA_FROM_DEVICE);

        packet = page_address(desc_data->rx.hdr.pa.pages) +
                 desc_data->rx.hdr.pa.pages_offset;
        copy_len = (desc_data->rx.hdr_len) ? desc_data->rx.hdr_len : len;
        copy_len = min(desc_data->rx.hdr.dma_len, copy_len);
        skb_copy_to_linear_data(skb, packet, copy_len);
        skb_put(skb, copy_len);

        len -= copy_len;
        if (len) {
                /* Add the remaining data as a frag */
                dma_sync_single_range_for_cpu(pdata->dev,
                                              desc_data->rx.buf.dma_base,
                                              desc_data->rx.buf.dma_off,
                                              desc_data->rx.buf.dma_len,
                                              DMA_FROM_DEVICE);

                skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
                                desc_data->rx.buf.pa.pages,
                                desc_data->rx.buf.pa.pages_offset,
                                len, desc_data->rx.buf.dma_len);
                desc_data->rx.buf.pa.pages = NULL;
        }

        return skb;
}

static int xlgmac_tx_poll(struct xlgmac_channel *channel)
{
        struct xlgmac_pdata *pdata = channel->pdata;
        struct xlgmac_ring *ring = channel->tx_ring;
        struct net_device *netdev = pdata->netdev;
        unsigned int tx_packets = 0, tx_bytes = 0;
        struct xlgmac_desc_data *desc_data;
        struct xlgmac_dma_desc *dma_desc;
        struct xlgmac_desc_ops *desc_ops;
        struct xlgmac_hw_ops *hw_ops;
        struct netdev_queue *txq;
        int processed = 0;
        unsigned int cur;

        desc_ops = &pdata->desc_ops;
        hw_ops = &pdata->hw_ops;

        /* Nothing to do if there isn't a Tx ring for this channel */
        if (!ring)
                return 0;

        cur = ring->cur;

        /* Be sure we get ring->cur before accessing descriptor data */
        smp_rmb();

        txq = netdev_get_tx_queue(netdev, channel->queue_index);

        while ((processed < XLGMAC_TX_DESC_MAX_PROC) &&
               (ring->dirty != cur)) {
                desc_data = XLGMAC_GET_DESC_DATA(ring, ring->dirty);
                dma_desc = desc_data->dma_desc;

                if (!hw_ops->tx_complete(dma_desc))
                        break;

                /* Make sure descriptor fields are read after reading
                 * the OWN bit
                 */
                dma_rmb();

                if (netif_msg_tx_done(pdata))
                        xlgmac_dump_tx_desc(pdata, ring, ring->dirty, 1, 0);

                if (hw_ops->is_last_desc(dma_desc)) {
                        tx_packets += desc_data->tx.packets;
                        tx_bytes += desc_data->tx.bytes;
                }

                /* Free the SKB and reset the descriptor for re-use */
                desc_ops->unmap_desc_data(pdata, desc_data);
                hw_ops->tx_desc_reset(desc_data);

                processed++;
                ring->dirty++;
        }

        if (!processed)
                return 0;

        netdev_tx_completed_queue(txq, tx_packets, tx_bytes);

        if ((ring->tx.queue_stopped == 1) &&
            (xlgmac_tx_avail_desc(ring) > XLGMAC_TX_DESC_MIN_FREE)) {
                ring->tx.queue_stopped = 0;
                netif_tx_wake_queue(txq);
        }

        XLGMAC_PR("processed=%d\n", processed);

        return processed;
}

static int xlgmac_rx_poll(struct xlgmac_channel *channel, int budget)
{
        struct xlgmac_pdata *pdata = channel->pdata;
        struct xlgmac_ring *ring = channel->rx_ring;
        struct net_device *netdev = pdata->netdev;
        unsigned int len, dma_desc_len, max_len;
        unsigned int context_next, context;
        struct xlgmac_desc_data *desc_data;
        struct xlgmac_pkt_info *pkt_info;
        unsigned int incomplete, error;
        struct xlgmac_hw_ops *hw_ops;
        unsigned int received = 0;
        struct napi_struct *napi;
        struct sk_buff *skb;
        int packet_count = 0;

        hw_ops = &pdata->hw_ops;

        /* Nothing to do if there isn't a Rx ring for this channel */
        if (!ring)
                return 0;

        incomplete = 0;
        context_next = 0;

        napi = (pdata->per_channel_irq) ? &channel->napi : &pdata->napi;

        desc_data = XLGMAC_GET_DESC_DATA(ring, ring->cur);
        pkt_info = &ring->pkt_info;
        while (packet_count < budget) {
                /* First time in loop see if we need to restore state */
                if (!received && desc_data->state_saved) {
                        skb = desc_data->state.skb;
                        error = desc_data->state.error;
                        len = desc_data->state.len;
                } else {
                        memset(pkt_info, 0, sizeof(*pkt_info));
                        skb = NULL;
                        error = 0;
                        len = 0;
                }

read_again:
                desc_data = XLGMAC_GET_DESC_DATA(ring, ring->cur);

                if (xlgmac_rx_dirty_desc(ring) > XLGMAC_RX_DESC_MAX_DIRTY)
                        xlgmac_rx_refresh(channel);

                if (hw_ops->dev_read(channel))
                        break;

                received++;
                ring->cur++;

                incomplete = XLGMAC_GET_REG_BITS(
                                        pkt_info->attributes,
                                        RX_PACKET_ATTRIBUTES_INCOMPLETE_POS,
                                        RX_PACKET_ATTRIBUTES_INCOMPLETE_LEN);
                context_next = XLGMAC_GET_REG_BITS(
                                        pkt_info->attributes,
                                        RX_PACKET_ATTRIBUTES_CONTEXT_NEXT_POS,
                                        RX_PACKET_ATTRIBUTES_CONTEXT_NEXT_LEN);
                context = XLGMAC_GET_REG_BITS(
                                        pkt_info->attributes,
                                        RX_PACKET_ATTRIBUTES_CONTEXT_POS,
                                        RX_PACKET_ATTRIBUTES_CONTEXT_LEN);

                /* Earlier error, just drain the remaining data */
                if ((incomplete || context_next) && error)
                        goto read_again;

                if (error || pkt_info->errors) {
                        if (pkt_info->errors)
                                netif_err(pdata, rx_err, netdev,
                                          "error in received packet\n");
                        dev_kfree_skb(skb);
                        goto next_packet;
                }

                if (!context) {
                        /* Length is cumulative, get this descriptor's length */
                        dma_desc_len = desc_data->rx.len - len;
                        len += dma_desc_len;

                        if (dma_desc_len && !skb) {
                                skb = xlgmac_create_skb(pdata, napi, desc_data,
                                                        dma_desc_len);
                                if (!skb)
                                        error = 1;
                        } else if (dma_desc_len) {
                                dma_sync_single_range_for_cpu(
                                                pdata->dev,
                                                desc_data->rx.buf.dma_base,
                                                desc_data->rx.buf.dma_off,
                                                desc_data->rx.buf.dma_len,
                                                DMA_FROM_DEVICE);

                                skb_add_rx_frag(
                                        skb, skb_shinfo(skb)->nr_frags,
                                        desc_data->rx.buf.pa.pages,
                                        desc_data->rx.buf.pa.pages_offset,
                                        dma_desc_len,
                                        desc_data->rx.buf.dma_len);
                                desc_data->rx.buf.pa.pages = NULL;
                        }
                }

                if (incomplete || context_next)
                        goto read_again;

                if (!skb)
                        goto next_packet;

                /* Be sure we don't exceed the configured MTU */
                max_len = netdev->mtu + ETH_HLEN;
                if (!(netdev->features & NETIF_F_HW_VLAN_CTAG_RX) &&
                    (skb->protocol == htons(ETH_P_8021Q)))
                        max_len += VLAN_HLEN;

                if (skb->len > max_len) {
                        netif_err(pdata, rx_err, netdev,
                                  "packet length exceeds configured MTU\n");
                        dev_kfree_skb(skb);
                        goto next_packet;
                }

                if (netif_msg_pktdata(pdata))
                        xlgmac_print_pkt(netdev, skb, false);

                skb_checksum_none_assert(skb);
                if (XLGMAC_GET_REG_BITS(pkt_info->attributes,
                                        RX_PACKET_ATTRIBUTES_CSUM_DONE_POS,
                                    RX_PACKET_ATTRIBUTES_CSUM_DONE_LEN))
                        skb->ip_summed = CHECKSUM_UNNECESSARY;

                if (XLGMAC_GET_REG_BITS(pkt_info->attributes,
                                        RX_PACKET_ATTRIBUTES_VLAN_CTAG_POS,
                                    RX_PACKET_ATTRIBUTES_VLAN_CTAG_LEN)) {
                        __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
                                               pkt_info->vlan_ctag);
                        pdata->stats.rx_vlan_packets++;
                }

                if (XLGMAC_GET_REG_BITS(pkt_info->attributes,
                                        RX_PACKET_ATTRIBUTES_RSS_HASH_POS,
                                    RX_PACKET_ATTRIBUTES_RSS_HASH_LEN))
                        skb_set_hash(skb, pkt_info->rss_hash,
                                     pkt_info->rss_hash_type);

                skb->dev = netdev;
                skb->protocol = eth_type_trans(skb, netdev);
                skb_record_rx_queue(skb, channel->queue_index);

                napi_gro_receive(napi, skb);

next_packet:
                packet_count++;
        }

        /* Check if we need to save state before leaving */
        if (received && (incomplete || context_next)) {
                desc_data = XLGMAC_GET_DESC_DATA(ring, ring->cur);
                desc_data->state_saved = 1;
                desc_data->state.skb = skb;
                desc_data->state.len = len;
                desc_data->state.error = error;
        }

        XLGMAC_PR("packet_count = %d\n", packet_count);

        return packet_count;
}

static int xlgmac_one_poll(struct napi_struct *napi, int budget)
{
        struct xlgmac_channel *channel = container_of(napi,
                                                struct xlgmac_channel,
                                                napi);
        int processed = 0;

        XLGMAC_PR("budget=%d\n", budget);

        /* Cleanup Tx ring first */
        xlgmac_tx_poll(channel);

        /* Process Rx ring next */
        processed = xlgmac_rx_poll(channel, budget);

        /* If we processed everything, we are done */
        if (processed < budget) {
                /* Turn off polling */
                napi_complete_done(napi, processed);

                /* Enable Tx and Rx interrupts */
                enable_irq(channel->dma_irq);
        }

        XLGMAC_PR("received = %d\n", processed);

        return processed;
}

static int xlgmac_all_poll(struct napi_struct *napi, int budget)
{
        struct xlgmac_pdata *pdata = container_of(napi,
                                                   struct xlgmac_pdata,
                                                   napi);
        struct xlgmac_channel *channel;
        int processed, last_processed;
        int ring_budget;
        unsigned int i;

        XLGMAC_PR("budget=%d\n", budget);

        processed = 0;
        ring_budget = budget / pdata->rx_ring_count;
        do {
                last_processed = processed;

                channel = pdata->channel_head;
                for (i = 0; i < pdata->channel_count; i++, channel++) {
                        /* Cleanup Tx ring first */
                        xlgmac_tx_poll(channel);

                        /* Process Rx ring next */
                        if (ring_budget > (budget - processed))
                                ring_budget = budget - processed;
                        processed += xlgmac_rx_poll(channel, ring_budget);
                }
        } while ((processed < budget) && (processed != last_processed));

        /* If we processed everything, we are done */
        if (processed < budget) {
                /* Turn off polling */
                napi_complete_done(napi, processed);

                /* Enable Tx and Rx interrupts */
                xlgmac_enable_rx_tx_ints(pdata);
        }

        XLGMAC_PR("received = %d\n", processed);

        return processed;
}