/*
 * Copyright (c) 2013 Johannes Berg <johannes@sipsolutions.net>
 *
 *  This file is free software: you may copy, redistribute and/or modify it
 *  under the terms of the GNU General Public License as published by the
 *  Free Software Foundation, either version 2 of the License, or (at your
 *  option) any later version.
 *
 *  This file is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * This file incorporates work covered by the following copyright and
 * permission notice:
 *
 * Copyright (c) 2012 Qualcomm Atheros, Inc.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <linux/module.h>
#include <linux/pci.h>
#include <linux/interrupt.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/if_vlan.h>
#include <linux/mdio.h>
#include <linux/aer.h>
#include <linux/bitops.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <net/ip6_checksum.h>
#include <linux/crc32.h>
#include "alx.h"
#include "hw.h"
#include "reg.h"

const char alx_drv_name[] = "alx";

static bool msix = true;
module_param(msix, bool, 0);
MODULE_PARM_DESC(msix, "Enable msi-x interrupt support (default: true)");

static void alx_free_txbuf(struct alx_tx_queue *txq, int entry)
{
        struct alx_buffer *txb = &txq->bufs[entry];

        if (dma_unmap_len(txb, size)) {
                dma_unmap_single(txq->dev,
                                 dma_unmap_addr(txb, dma),
                                 dma_unmap_len(txb, size),
                                 DMA_TO_DEVICE);
                dma_unmap_len_set(txb, size, 0);
        }

        if (txb->skb) {
                dev_kfree_skb_any(txb->skb);
                txb->skb = NULL;
        }
}

static int alx_refill_rx_ring(struct alx_priv *alx, gfp_t gfp)
{
        struct alx_rx_queue *rxq = alx->qnapi[0]->rxq;
        struct sk_buff *skb;
        struct alx_buffer *cur_buf;
        dma_addr_t dma;
        u16 cur, next, count = 0;

        next = cur = rxq->write_idx;
        if (++next == alx->rx_ringsz)
                next = 0;
        cur_buf = &rxq->bufs[cur];

        while (!cur_buf->skb && next != rxq->read_idx) {
                struct alx_rfd *rfd = &rxq->rfd[cur];

                /*
                 * When DMA RX address is set to something like
                 * 0x....fc0, it will be very likely to cause DMA
                 * RFD overflow issue.
                 *
                 * To work around it, we apply rx skb with 64 bytes
                 * longer space, and offset the address whenever
                 * 0x....fc0 is detected.
                 */
                skb = __netdev_alloc_skb(alx->dev, alx->rxbuf_size + 64, gfp);
                if (!skb)
                        break;

                if (((unsigned long)skb->data & 0xfff) == 0xfc0)
                        skb_reserve(skb, 64);

                dma = dma_map_single(&alx->hw.pdev->dev,
                                     skb->data, alx->rxbuf_size,
                                     DMA_FROM_DEVICE);
                if (dma_mapping_error(&alx->hw.pdev->dev, dma)) {
                        dev_kfree_skb(skb);
                        break;
                }

                /* Unfortunately, RX descriptor buffers must be 4-byte
                 * aligned, so we can't use IP alignment.
                 */
                if (WARN_ON(dma & 3)) {
                        dev_kfree_skb(skb);
                        break;
                }

                cur_buf->skb = skb;
                dma_unmap_len_set(cur_buf, size, alx->rxbuf_size);
                dma_unmap_addr_set(cur_buf, dma, dma);
                rfd->addr = cpu_to_le64(dma);

                cur = next;
                if (++next == alx->rx_ringsz)
                        next = 0;
                cur_buf = &rxq->bufs[cur];
                count++;
        }

        if (count) {
                /* flush all updates before updating hardware */
                wmb();
                rxq->write_idx = cur;
                alx_write_mem16(&alx->hw, ALX_RFD_PIDX, cur);
        }

        return count;
}

static struct alx_tx_queue *alx_tx_queue_mapping(struct alx_priv *alx,
                                                 struct sk_buff *skb)
{
        unsigned int r_idx = skb->queue_mapping;

        if (r_idx >= alx->num_txq)
                r_idx = r_idx % alx->num_txq;

        return alx->qnapi[r_idx]->txq;
}

static struct netdev_queue *alx_get_tx_queue(const struct alx_tx_queue *txq)
{
        return netdev_get_tx_queue(txq->netdev, txq->queue_idx);
}

static inline int alx_tpd_avail(struct alx_tx_queue *txq)
{
        if (txq->write_idx >= txq->read_idx)
                return txq->count + txq->read_idx - txq->write_idx - 1;
        return txq->read_idx - txq->write_idx - 1;
}

static bool alx_clean_tx_irq(struct alx_tx_queue *txq)
{
        struct alx_priv *alx;
        struct netdev_queue *tx_queue;
        u16 hw_read_idx, sw_read_idx;
        unsigned int total_bytes = 0, total_packets = 0;
        int budget = ALX_DEFAULT_TX_WORK;

        alx = netdev_priv(txq->netdev);
        tx_queue = alx_get_tx_queue(txq);

        sw_read_idx = txq->read_idx;
        hw_read_idx = alx_read_mem16(&alx->hw, txq->c_reg);

        if (sw_read_idx != hw_read_idx) {
                while (sw_read_idx != hw_read_idx && budget > 0) {
                        struct sk_buff *skb;

                        skb = txq->bufs[sw_read_idx].skb;
                        if (skb) {
                                total_bytes += skb->len;
                                total_packets++;
                                budget--;
                        }

                        alx_free_txbuf(txq, sw_read_idx);

                        if (++sw_read_idx == txq->count)
                                sw_read_idx = 0;
                }
                txq->read_idx = sw_read_idx;

                netdev_tx_completed_queue(tx_queue, total_packets, total_bytes);
        }

        if (netif_tx_queue_stopped(tx_queue) && netif_carrier_ok(alx->dev) &&
            alx_tpd_avail(txq) > txq->count / 4)
                netif_tx_wake_queue(tx_queue);

        return sw_read_idx == hw_read_idx;
}

static void alx_schedule_link_check(struct alx_priv *alx)
{
        schedule_work(&alx->link_check_wk);
}

static void alx_schedule_reset(struct alx_priv *alx)
{
        schedule_work(&alx->reset_wk);
}

static int alx_clean_rx_irq(struct alx_rx_queue *rxq, int budget)
{
        struct alx_priv *alx;
        struct alx_rrd *rrd;
        struct alx_buffer *rxb;
        struct sk_buff *skb;
        u16 length, rfd_cleaned = 0;
        int work = 0;

        alx = netdev_priv(rxq->netdev);

        while (work < budget) {
                rrd = &rxq->rrd[rxq->rrd_read_idx];
                if (!(rrd->word3 & cpu_to_le32(1 << RRD_UPDATED_SHIFT)))
                        break;
                rrd->word3 &= ~cpu_to_le32(1 << RRD_UPDATED_SHIFT);

                if (ALX_GET_FIELD(le32_to_cpu(rrd->word0),
                                  RRD_SI) != rxq->read_idx ||
                    ALX_GET_FIELD(le32_to_cpu(rrd->word0),
                                  RRD_NOR) != 1) {
                        alx_schedule_reset(alx);
                        return work;
                }

                rxb = &rxq->bufs[rxq->read_idx];
                dma_unmap_single(rxq->dev,
                                 dma_unmap_addr(rxb, dma),
                                 dma_unmap_len(rxb, size),
                                 DMA_FROM_DEVICE);
                dma_unmap_len_set(rxb, size, 0);
                skb = rxb->skb;
                rxb->skb = NULL;

                if (rrd->word3 & cpu_to_le32(1 << RRD_ERR_RES_SHIFT) ||
                    rrd->word3 & cpu_to_le32(1 << RRD_ERR_LEN_SHIFT)) {
                        rrd->word3 = 0;
                        dev_kfree_skb_any(skb);
                        goto next_pkt;
                }

                length = ALX_GET_FIELD(le32_to_cpu(rrd->word3),
                                       RRD_PKTLEN) - ETH_FCS_LEN;
                skb_put(skb, length);
                skb->protocol = eth_type_trans(skb, rxq->netdev);

                skb_checksum_none_assert(skb);
                if (alx->dev->features & NETIF_F_RXCSUM &&
                    !(rrd->word3 & (cpu_to_le32(1 << RRD_ERR_L4_SHIFT) |
                                    cpu_to_le32(1 << RRD_ERR_IPV4_SHIFT)))) {
                        switch (ALX_GET_FIELD(le32_to_cpu(rrd->word2),
                                              RRD_PID)) {
                        case RRD_PID_IPV6UDP:
                        case RRD_PID_IPV4UDP:
                        case RRD_PID_IPV4TCP:
                        case RRD_PID_IPV6TCP:
                                skb->ip_summed = CHECKSUM_UNNECESSARY;
                                break;
                        }
                }

                napi_gro_receive(&rxq->np->napi, skb);
                work++;

next_pkt:
                if (++rxq->read_idx == rxq->count)
                        rxq->read_idx = 0;
                if (++rxq->rrd_read_idx == rxq->count)
                        rxq->rrd_read_idx = 0;

                if (++rfd_cleaned > ALX_RX_ALLOC_THRESH)
                        rfd_cleaned -= alx_refill_rx_ring(alx, GFP_ATOMIC);
        }

        if (rfd_cleaned)
                alx_refill_rx_ring(alx, GFP_ATOMIC);

        return work;
}

static int alx_poll(struct napi_struct *napi, int budget)
{
        struct alx_napi *np = container_of(napi, struct alx_napi, napi);
        struct alx_priv *alx = np->alx;
        struct alx_hw *hw = &alx->hw;
        unsigned long flags;
        bool tx_complete = true;
        int work = 0;

        if (np->txq)
                tx_complete = alx_clean_tx_irq(np->txq);
        if (np->rxq)
                work = alx_clean_rx_irq(np->rxq, budget);

        if (!tx_complete || work == budget)
                return budget;

        napi_complete(&np->napi);

        /* enable interrupt */
        if (alx->flags & ALX_FLAG_USING_MSIX) {
                alx_mask_msix(hw, np->vec_idx, false);
        } else {
                spin_lock_irqsave(&alx->irq_lock, flags);
                alx->int_mask |= ALX_ISR_TX_Q0 | ALX_ISR_RX_Q0;
                alx_write_mem32(hw, ALX_IMR, alx->int_mask);
                spin_unlock_irqrestore(&alx->irq_lock, flags);
        }

        alx_post_write(hw);

        return work;
}

static bool alx_intr_handle_misc(struct alx_priv *alx, u32 intr)
{
        struct alx_hw *hw = &alx->hw;

        if (intr & ALX_ISR_FATAL) {
                netif_warn(alx, hw, alx->dev,
                           "fatal interrupt 0x%x, resetting\n", intr);
                alx_schedule_reset(alx);
                return true;
        }

        if (intr & ALX_ISR_ALERT)
                netdev_warn(alx->dev, "alert interrupt: 0x%x\n", intr);

        if (intr & ALX_ISR_PHY) {
                /* suppress PHY interrupt, because the source
                 * is from PHY internal. only the internal status
                 * is cleared, the interrupt status could be cleared.
                 */
                alx->int_mask &= ~ALX_ISR_PHY;
                alx_write_mem32(hw, ALX_IMR, alx->int_mask);
                alx_schedule_link_check(alx);
        }

        return false;
}

static irqreturn_t alx_intr_handle(struct alx_priv *alx, u32 intr)
{
        struct alx_hw *hw = &alx->hw;

        spin_lock(&alx->irq_lock);

        /* ACK interrupt */
        alx_write_mem32(hw, ALX_ISR, intr | ALX_ISR_DIS);
        intr &= alx->int_mask;

        if (alx_intr_handle_misc(alx, intr))
                goto out;

        if (intr & (ALX_ISR_TX_Q0 | ALX_ISR_RX_Q0)) {
                napi_schedule(&alx->qnapi[0]->napi);
                /* mask rx/tx interrupt, enable them when napi complete */
                alx->int_mask &= ~ALX_ISR_ALL_QUEUES;
                alx_write_mem32(hw, ALX_IMR, alx->int_mask);
        }

        alx_write_mem32(hw, ALX_ISR, 0);

 out:
        spin_unlock(&alx->irq_lock);
        return IRQ_HANDLED;
}

static irqreturn_t alx_intr_msix_ring(int irq, void *data)
{
        struct alx_napi *np = data;
        struct alx_hw *hw = &np->alx->hw;

        /* mask interrupt to ACK chip */
        alx_mask_msix(hw, np->vec_idx, true);
        /* clear interrupt status */
        alx_write_mem32(hw, ALX_ISR, np->vec_mask);

        napi_schedule(&np->napi);

        return IRQ_HANDLED;
}

static irqreturn_t alx_intr_msix_misc(int irq, void *data)
{
        struct alx_priv *alx = data;
        struct alx_hw *hw = &alx->hw;
        u32 intr;

        /* mask interrupt to ACK chip */
        alx_mask_msix(hw, 0, true);

        /* read interrupt status */
        intr = alx_read_mem32(hw, ALX_ISR);
        intr &= (alx->int_mask & ~ALX_ISR_ALL_QUEUES);

        if (alx_intr_handle_misc(alx, intr))
                return IRQ_HANDLED;

        /* clear interrupt status */
        alx_write_mem32(hw, ALX_ISR, intr);

        /* enable interrupt again */
        alx_mask_msix(hw, 0, false);

        return IRQ_HANDLED;
}

static irqreturn_t alx_intr_msi(int irq, void *data)
{
        struct alx_priv *alx = data;

        return alx_intr_handle(alx, alx_read_mem32(&alx->hw, ALX_ISR));
}

static irqreturn_t alx_intr_legacy(int irq, void *data)
{
        struct alx_priv *alx = data;
        struct alx_hw *hw = &alx->hw;
        u32 intr;

        intr = alx_read_mem32(hw, ALX_ISR);

        if (intr & ALX_ISR_DIS || !(intr & alx->int_mask))
                return IRQ_NONE;

        return alx_intr_handle(alx, intr);
}

static const u16 txring_header_reg[] = {ALX_TPD_PRI0_ADDR_LO,
                                        ALX_TPD_PRI1_ADDR_LO,
                                        ALX_TPD_PRI2_ADDR_LO,
                                        ALX_TPD_PRI3_ADDR_LO};

static void alx_init_ring_ptrs(struct alx_priv *alx)
{
        struct alx_hw *hw = &alx->hw;
        u32 addr_hi = ((u64)alx->descmem.dma) >> 32;
        struct alx_napi *np;
        int i;

        for (i = 0; i < alx->num_napi; i++) {
                np = alx->qnapi[i];
                if (np->txq) {
                        np->txq->read_idx = 0;
                        np->txq->write_idx = 0;
                        alx_write_mem32(hw,
                                        txring_header_reg[np->txq->queue_idx],
                                        np->txq->tpd_dma);
                }

                if (np->rxq) {
                        np->rxq->read_idx = 0;
                        np->rxq->write_idx = 0;
                        np->rxq->rrd_read_idx = 0;
                        alx_write_mem32(hw, ALX_RRD_ADDR_LO, np->rxq->rrd_dma);
                        alx_write_mem32(hw, ALX_RFD_ADDR_LO, np->rxq->rfd_dma);
                }
        }

        alx_write_mem32(hw, ALX_TX_BASE_ADDR_HI, addr_hi);
        alx_write_mem32(hw, ALX_TPD_RING_SZ, alx->tx_ringsz);

        alx_write_mem32(hw, ALX_RX_BASE_ADDR_HI, addr_hi);
        alx_write_mem32(hw, ALX_RRD_RING_SZ, alx->rx_ringsz);
        alx_write_mem32(hw, ALX_RFD_RING_SZ, alx->rx_ringsz);
        alx_write_mem32(hw, ALX_RFD_BUF_SZ, alx->rxbuf_size);

        /* load these pointers into the chip */
        alx_write_mem32(hw, ALX_SRAM9, ALX_SRAM_LOAD_PTR);
}

static void alx_free_txring_buf(struct alx_tx_queue *txq)
{
        int i;

        if (!txq->bufs)
                return;

        for (i = 0; i < txq->count; i++)
                alx_free_txbuf(txq, i);

        memset(txq->bufs, 0, txq->count * sizeof(struct alx_buffer));
        memset(txq->tpd, 0, txq->count * sizeof(struct alx_txd));
        txq->write_idx = 0;
        txq->read_idx = 0;

        netdev_tx_reset_queue(alx_get_tx_queue(txq));
}

static void alx_free_rxring_buf(struct alx_rx_queue *rxq)
{
        struct alx_buffer *cur_buf;
        u16 i;

        if (!rxq->bufs)
                return;

        for (i = 0; i < rxq->count; i++) {
                cur_buf = rxq->bufs + i;
                if (cur_buf->skb) {
                        dma_unmap_single(rxq->dev,
                                         dma_unmap_addr(cur_buf, dma),
                                         dma_unmap_len(cur_buf, size),
                                         DMA_FROM_DEVICE);
                        dev_kfree_skb(cur_buf->skb);
                        cur_buf->skb = NULL;
                        dma_unmap_len_set(cur_buf, size, 0);
                        dma_unmap_addr_set(cur_buf, dma, 0);
                }
        }

        rxq->write_idx = 0;
        rxq->read_idx = 0;
        rxq->rrd_read_idx = 0;
}

static void alx_free_buffers(struct alx_priv *alx)
{
        int i;

        for (i = 0; i < alx->num_txq; i++)
                if (alx->qnapi[i] && alx->qnapi[i]->txq)
                        alx_free_txring_buf(alx->qnapi[i]->txq);

        if (alx->qnapi[0] && alx->qnapi[0]->rxq)
                alx_free_rxring_buf(alx->qnapi[0]->rxq);
}

static int alx_reinit_rings(struct alx_priv *alx)
{
        alx_free_buffers(alx);

        alx_init_ring_ptrs(alx);

        if (!alx_refill_rx_ring(alx, GFP_KERNEL))
                return -ENOMEM;

        return 0;
}

static void alx_add_mc_addr(struct alx_hw *hw, const u8 *addr, u32 *mc_hash)
{
        u32 crc32, bit, reg;

        crc32 = ether_crc(ETH_ALEN, addr);
        reg = (crc32 >> 31) & 0x1;
        bit = (crc32 >> 26) & 0x1F;

        mc_hash[reg] |= BIT(bit);
}

static void __alx_set_rx_mode(struct net_device *netdev)
{
        struct alx_priv *alx = netdev_priv(netdev);
        struct alx_hw *hw = &alx->hw;
        struct netdev_hw_addr *ha;
        u32 mc_hash[2] = {};

        if (!(netdev->flags & IFF_ALLMULTI)) {
                netdev_for_each_mc_addr(ha, netdev)
                        alx_add_mc_addr(hw, ha->addr, mc_hash);

                alx_write_mem32(hw, ALX_HASH_TBL0, mc_hash[0]);
                alx_write_mem32(hw, ALX_HASH_TBL1, mc_hash[1]);
        }

        hw->rx_ctrl &= ~(ALX_MAC_CTRL_MULTIALL_EN | ALX_MAC_CTRL_PROMISC_EN);
        if (netdev->flags & IFF_PROMISC)
                hw->rx_ctrl |= ALX_MAC_CTRL_PROMISC_EN;
        if (netdev->flags & IFF_ALLMULTI)
                hw->rx_ctrl |= ALX_MAC_CTRL_MULTIALL_EN;

        alx_write_mem32(hw, ALX_MAC_CTRL, hw->rx_ctrl);
}

static void alx_set_rx_mode(struct net_device *netdev)
{
        __alx_set_rx_mode(netdev);
}

static int alx_set_mac_address(struct net_device *netdev, void *data)
{
        struct alx_priv *alx = netdev_priv(netdev);
        struct alx_hw *hw = &alx->hw;
        struct sockaddr *addr = data;

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

        if (netdev->addr_assign_type & NET_ADDR_RANDOM)
                netdev->addr_assign_type ^= NET_ADDR_RANDOM;

        memcpy(netdev->dev_addr, addr->sa_data, netdev->addr_len);
        memcpy(hw->mac_addr, addr->sa_data, netdev->addr_len);
        alx_set_macaddr(hw, hw->mac_addr);

        return 0;
}

static int alx_alloc_tx_ring(struct alx_priv *alx, struct alx_tx_queue *txq,
                             int offset)
{
        txq->bufs = kcalloc(txq->count, sizeof(struct alx_buffer), GFP_KERNEL);
        if (!txq->bufs)
                return -ENOMEM;

        txq->tpd = alx->descmem.virt + offset;
        txq->tpd_dma = alx->descmem.dma + offset;
        offset += sizeof(struct alx_txd) * txq->count;

        return offset;
}

static int alx_alloc_rx_ring(struct alx_priv *alx, struct alx_rx_queue *rxq,
                             int offset)
{
        rxq->bufs = kcalloc(rxq->count, sizeof(struct alx_buffer), GFP_KERNEL);
        if (!rxq->bufs)
                return -ENOMEM;

        rxq->rrd = alx->descmem.virt + offset;
        rxq->rrd_dma = alx->descmem.dma + offset;
        offset += sizeof(struct alx_rrd) * rxq->count;

        rxq->rfd = alx->descmem.virt + offset;
        rxq->rfd_dma = alx->descmem.dma + offset;
        offset += sizeof(struct alx_rfd) * rxq->count;

        return offset;
}

static int alx_alloc_rings(struct alx_priv *alx)
{
        int i, offset = 0;

        /* physical tx/rx ring descriptors
         *
         * Allocate them as a single chunk because they must not cross a
         * 4G boundary (hardware has a single register for high 32 bits
         * of addresses only)
         */
        alx->descmem.size = sizeof(struct alx_txd) * alx->tx_ringsz *
                            alx->num_txq +
                            sizeof(struct alx_rrd) * alx->rx_ringsz +
                            sizeof(struct alx_rfd) * alx->rx_ringsz;
        alx->descmem.virt = dma_zalloc_coherent(&alx->hw.pdev->dev,
                                                alx->descmem.size,
                                                &alx->descmem.dma,
                                                GFP_KERNEL);
        if (!alx->descmem.virt)
                return -ENOMEM;

        /* alignment requirements */
        BUILD_BUG_ON(sizeof(struct alx_txd) % 8);
        BUILD_BUG_ON(sizeof(struct alx_rrd) % 8);

        for (i = 0; i < alx->num_txq; i++) {
                offset = alx_alloc_tx_ring(alx, alx->qnapi[i]->txq, offset);
                if (offset < 0) {
                        netdev_err(alx->dev, "Allocation of tx buffer failed!\n");
                        return -ENOMEM;
                }
        }

        offset = alx_alloc_rx_ring(alx, alx->qnapi[0]->rxq, offset);
        if (offset < 0) {
                netdev_err(alx->dev, "Allocation of rx buffer failed!\n");
                return -ENOMEM;
        }

        return 0;
}

static void alx_free_rings(struct alx_priv *alx)
{
        int i;

        alx_free_buffers(alx);

        for (i = 0; i < alx->num_txq; i++)
                if (alx->qnapi[i] && alx->qnapi[i]->txq)
                        kfree(alx->qnapi[i]->txq->bufs);

        if (alx->qnapi[0] && alx->qnapi[0]->rxq)
                kfree(alx->qnapi[0]->rxq->bufs);

        if (alx->descmem.virt)
                dma_free_coherent(&alx->hw.pdev->dev,
                                  alx->descmem.size,
                                  alx->descmem.virt,
                                  alx->descmem.dma);
}

static void alx_free_napis(struct alx_priv *alx)
{
        struct alx_napi *np;
        int i;

        for (i = 0; i < alx->num_napi; i++) {
                np = alx->qnapi[i];
                if (!np)
                        continue;

                netif_napi_del(&np->napi);
                kfree(np->txq);
                kfree(np->rxq);
                kfree(np);
                alx->qnapi[i] = NULL;
        }
}

static const u16 tx_pidx_reg[] = {ALX_TPD_PRI0_PIDX, ALX_TPD_PRI1_PIDX,
                                  ALX_TPD_PRI2_PIDX, ALX_TPD_PRI3_PIDX};
static const u16 tx_cidx_reg[] = {ALX_TPD_PRI0_CIDX, ALX_TPD_PRI1_CIDX,
                                  ALX_TPD_PRI2_CIDX, ALX_TPD_PRI3_CIDX};
static const u32 tx_vect_mask[] = {ALX_ISR_TX_Q0, ALX_ISR_TX_Q1,
                                   ALX_ISR_TX_Q2, ALX_ISR_TX_Q3};
static const u32 rx_vect_mask[] = {ALX_ISR_RX_Q0, ALX_ISR_RX_Q1,
                                   ALX_ISR_RX_Q2, ALX_ISR_RX_Q3,
                                   ALX_ISR_RX_Q4, ALX_ISR_RX_Q5,
                                   ALX_ISR_RX_Q6, ALX_ISR_RX_Q7};

static int alx_alloc_napis(struct alx_priv *alx)
{
        struct alx_napi *np;
        struct alx_rx_queue *rxq;
        struct alx_tx_queue *txq;
        int i;

        alx->int_mask &= ~ALX_ISR_ALL_QUEUES;

        /* allocate alx_napi structures */
        for (i = 0; i < alx->num_napi; i++) {
                np = kzalloc(sizeof(struct alx_napi), GFP_KERNEL);
                if (!np)
                        goto err_out;

                np->alx = alx;
                netif_napi_add(alx->dev, &np->napi, alx_poll, 64);
                alx->qnapi[i] = np;
        }

        /* allocate tx queues */
        for (i = 0; i < alx->num_txq; i++) {
                np = alx->qnapi[i];
                txq = kzalloc(sizeof(*txq), GFP_KERNEL);
                if (!txq)
                        goto err_out;

                np->txq = txq;
                txq->p_reg = tx_pidx_reg[i];
                txq->c_reg = tx_cidx_reg[i];
                txq->queue_idx = i;
                txq->count = alx->tx_ringsz;
                txq->netdev = alx->dev;
                txq->dev = &alx->hw.pdev->dev;
                np->vec_mask |= tx_vect_mask[i];
                alx->int_mask |= tx_vect_mask[i];
        }

        /* allocate rx queues */
        np = alx->qnapi[0];
        rxq = kzalloc(sizeof(*rxq), GFP_KERNEL);
        if (!rxq)
                goto err_out;

        np->rxq = rxq;
        rxq->np = alx->qnapi[0];
        rxq->queue_idx = 0;
        rxq->count = alx->rx_ringsz;
        rxq->netdev = alx->dev;
        rxq->dev = &alx->hw.pdev->dev;
        np->vec_mask |= rx_vect_mask[0];
        alx->int_mask |= rx_vect_mask[0];

        return 0;

err_out:
        netdev_err(alx->dev, "error allocating internal structures\n");
        alx_free_napis(alx);
        return -ENOMEM;
}

static const int txq_vec_mapping_shift[] = {
        0, ALX_MSI_MAP_TBL1_TXQ0_SHIFT,
        0, ALX_MSI_MAP_TBL1_TXQ1_SHIFT,
        1, ALX_MSI_MAP_TBL2_TXQ2_SHIFT,
        1, ALX_MSI_MAP_TBL2_TXQ3_SHIFT,
};

static void alx_config_vector_mapping(struct alx_priv *alx)
{
        struct alx_hw *hw = &alx->hw;
        u32 tbl[2] = {0, 0};
        int i, vector, idx, shift;

        if (alx->flags & ALX_FLAG_USING_MSIX) {
                /* tx mappings */
                for (i = 0, vector = 1; i < alx->num_txq; i++, vector++) {
                        idx = txq_vec_mapping_shift[i * 2];
                        shift = txq_vec_mapping_shift[i * 2 + 1];
                        tbl[idx] |= vector << shift;
                }

                /* rx mapping */
                tbl[0] |= 1 << ALX_MSI_MAP_TBL1_RXQ0_SHIFT;
        }

        alx_write_mem32(hw, ALX_MSI_MAP_TBL1, tbl[0]);
        alx_write_mem32(hw, ALX_MSI_MAP_TBL2, tbl[1]);
        alx_write_mem32(hw, ALX_MSI_ID_MAP, 0);
}

static bool alx_enable_msix(struct alx_priv *alx)
{
        int i, err, num_vec, num_txq, num_rxq;

        num_txq = min_t(int, num_online_cpus(), ALX_MAX_TX_QUEUES);
        num_rxq = 1;
        num_vec = max_t(int, num_txq, num_rxq) + 1;

        alx->msix_entries = kcalloc(num_vec, sizeof(struct msix_entry),
                                    GFP_KERNEL);
        if (!alx->msix_entries) {
                netdev_warn(alx->dev, "Allocation of msix entries failed!\n");
                return false;
        }

        for (i = 0; i < num_vec; i++)
                alx->msix_entries[i].entry = i;

        err = pci_enable_msix(alx->hw.pdev, alx->msix_entries, num_vec);
        if (err) {
                kfree(alx->msix_entries);
                netdev_warn(alx->dev, "Enabling MSI-X interrupts failed!\n");
                return false;
        }

        alx->num_vec = num_vec;
        alx->num_napi = num_vec - 1;
        alx->num_txq = num_txq;
        alx->num_rxq = num_rxq;

        return true;
}

static int alx_request_msix(struct alx_priv *alx)
{
        struct net_device *netdev = alx->dev;
        int i, err, vector = 0, free_vector = 0;

        err = request_irq(alx->msix_entries[0].vector, alx_intr_msix_misc,
                          0, netdev->name, alx);
        if (err)
                goto out_err;

        for (i = 0; i < alx->num_napi; i++) {
                struct alx_napi *np = alx->qnapi[i];

                vector++;

                if (np->txq && np->rxq)
                        sprintf(np->irq_lbl, "%s-TxRx-%u", netdev->name,
                                np->txq->queue_idx);
                else if (np->txq)
                        sprintf(np->irq_lbl, "%s-tx-%u", netdev->name,
                                np->txq->queue_idx);
                else if (np->rxq)
                        sprintf(np->irq_lbl, "%s-rx-%u", netdev->name,
                                np->rxq->queue_idx);
                else
                        sprintf(np->irq_lbl, "%s-unused", netdev->name);

                np->vec_idx = vector;
                err = request_irq(alx->msix_entries[vector].vector,
                                  alx_intr_msix_ring, 0, np->irq_lbl, np);
                if (err)
                        goto out_free;
        }
        return 0;

out_free:
        free_irq(alx->msix_entries[free_vector++].vector, alx);

        vector--;
        for (i = 0; i < vector; i++)
                free_irq(alx->msix_entries[free_vector++].vector,
                         alx->qnapi[i]);

out_err:
        return err;
}

static void alx_init_intr(struct alx_priv *alx, bool msix)
{
        if (msix) {
                if (alx_enable_msix(alx))
                        alx->flags |= ALX_FLAG_USING_MSIX;
        }

        if (!(alx->flags & ALX_FLAG_USING_MSIX)) {
                alx->num_vec = 1;
                alx->num_napi = 1;
                alx->num_txq = 1;
                alx->num_rxq = 1;

                if (!pci_enable_msi(alx->hw.pdev))
                        alx->flags |= ALX_FLAG_USING_MSI;
        }
}

static void alx_disable_advanced_intr(struct alx_priv *alx)
{
        if (alx->flags & ALX_FLAG_USING_MSIX) {
                kfree(alx->msix_entries);
                pci_disable_msix(alx->hw.pdev);
                alx->flags &= ~ALX_FLAG_USING_MSIX;
        }

        if (alx->flags & ALX_FLAG_USING_MSI) {
                pci_disable_msi(alx->hw.pdev);
                alx->flags &= ~ALX_FLAG_USING_MSI;
        }
}

static void alx_irq_enable(struct alx_priv *alx)
{
        struct alx_hw *hw = &alx->hw;
        int i;

        /* level-1 interrupt switch */
        alx_write_mem32(hw, ALX_ISR, 0);
        alx_write_mem32(hw, ALX_IMR, alx->int_mask);
        alx_post_write(hw);

        if (alx->flags & ALX_FLAG_USING_MSIX)
                /* enable all msix irqs */
                for (i = 0; i < alx->num_vec; i++)
                        alx_mask_msix(hw, i, false);
}

static void alx_irq_disable(struct alx_priv *alx)
{
        struct alx_hw *hw = &alx->hw;
        int i;

        alx_write_mem32(hw, ALX_ISR, ALX_ISR_DIS);
        alx_write_mem32(hw, ALX_IMR, 0);
        alx_post_write(hw);

        if (alx->flags & ALX_FLAG_USING_MSIX) {
                for (i = 0; i < alx->num_vec; i++) {
                        alx_mask_msix(hw, i, true);
                        synchronize_irq(alx->msix_entries[i].vector);
                }
        } else {
                synchronize_irq(alx->hw.pdev->irq);
        }
}

static int alx_realloc_resources(struct alx_priv *alx)
{
        int err;

        alx_free_rings(alx);
        alx_free_napis(alx);
        alx_disable_advanced_intr(alx);
        alx_init_intr(alx, false);

        err = alx_alloc_napis(alx);
        if (err)
                return err;

        err = alx_alloc_rings(alx);
        if (err)
                return err;

        return 0;
}

static int alx_request_irq(struct alx_priv *alx)
{
        struct pci_dev *pdev = alx->hw.pdev;
        struct alx_hw *hw = &alx->hw;
        int err;
        u32 msi_ctrl;

        msi_ctrl = (hw->imt >> 1) << ALX_MSI_RETRANS_TM_SHIFT;

        if (alx->flags & ALX_FLAG_USING_MSIX) {
                alx_write_mem32(hw, ALX_MSI_RETRANS_TIMER, msi_ctrl);
                err = alx_request_msix(alx);
                if (!err)
                        goto out;

                /* msix request failed, realloc resources */
                err = alx_realloc_resources(alx);
                if (err)
                        goto out;
        }

        if (alx->flags & ALX_FLAG_USING_MSI) {
                alx_write_mem32(hw, ALX_MSI_RETRANS_TIMER,
                                msi_ctrl | ALX_MSI_MASK_SEL_LINE);
                err = request_irq(pdev->irq, alx_intr_msi, 0,
                                  alx->dev->name, alx);
                if (!err)
                        goto out;
                /* fall back to legacy interrupt */
                alx->flags &= ~ALX_FLAG_USING_MSI;
                pci_disable_msi(alx->hw.pdev);
        }

        alx_write_mem32(hw, ALX_MSI_RETRANS_TIMER, 0);
        err = request_irq(pdev->irq, alx_intr_legacy, IRQF_SHARED,
                          alx->dev->name, alx);
out:
        if (!err)
                alx_config_vector_mapping(alx);
        else
                netdev_err(alx->dev, "IRQ registration failed!\n");
        return err;
}

static void alx_free_irq(struct alx_priv *alx)
{
        struct pci_dev *pdev = alx->hw.pdev;
        int i, vector = 0;

        if (alx->flags & ALX_FLAG_USING_MSIX) {
                free_irq(alx->msix_entries[vector++].vector, alx);
                for (i = 0; i < alx->num_napi; i++)
                        free_irq(alx->msix_entries[vector++].vector,
                                 alx->qnapi[i]);
        } else {
                free_irq(pdev->irq, alx);
        }

        alx_disable_advanced_intr(alx);
}

static int alx_identify_hw(struct alx_priv *alx)
{
        struct alx_hw *hw = &alx->hw;
        int rev = alx_hw_revision(hw);

        if (rev > ALX_REV_C0)
                return -EINVAL;

        hw->max_dma_chnl = rev >= ALX_REV_B0 ? 4 : 2;

        return 0;
}

static int alx_init_sw(struct alx_priv *alx)
{
        struct pci_dev *pdev = alx->hw.pdev;
        struct alx_hw *hw = &alx->hw;
        int err;

        err = alx_identify_hw(alx);
        if (err) {
                dev_err(&pdev->dev, "unrecognized chip, aborting\n");
                return err;
        }

        alx->hw.lnk_patch =
                pdev->device == ALX_DEV_ID_AR8161 &&
                pdev->subsystem_vendor == PCI_VENDOR_ID_ATTANSIC &&
                pdev->subsystem_device == 0x0091 &&
                pdev->revision == 0;

        hw->smb_timer = 400;
        hw->mtu = alx->dev->mtu;
        alx->rxbuf_size = ALX_MAX_FRAME_LEN(hw->mtu);
        alx->tx_ringsz = 256;
        alx->rx_ringsz = 512;
        hw->imt = 200;
        alx->int_mask = ALX_ISR_MISC;
        hw->dma_chnl = hw->max_dma_chnl;
        hw->ith_tpd = alx->tx_ringsz / 3;
        hw->link_speed = SPEED_UNKNOWN;
        hw->duplex = DUPLEX_UNKNOWN;
        hw->adv_cfg = ADVERTISED_Autoneg |
                      ADVERTISED_10baseT_Half |
                      ADVERTISED_10baseT_Full |
                      ADVERTISED_100baseT_Full |
                      ADVERTISED_100baseT_Half |
                      ADVERTISED_1000baseT_Full;
        hw->flowctrl = ALX_FC_ANEG | ALX_FC_RX | ALX_FC_TX;

        hw->rx_ctrl = ALX_MAC_CTRL_WOLSPED_SWEN |
                      ALX_MAC_CTRL_MHASH_ALG_HI5B |
                      ALX_MAC_CTRL_BRD_EN |
                      ALX_MAC_CTRL_PCRCE |
                      ALX_MAC_CTRL_CRCE |
                      ALX_MAC_CTRL_RXFC_EN |
                      ALX_MAC_CTRL_TXFC_EN |
                      7 << ALX_MAC_CTRL_PRMBLEN_SHIFT;

        return err;
}


static netdev_features_t alx_fix_features(struct net_device *netdev,
                                          netdev_features_t features)
{
        if (netdev->mtu > ALX_MAX_TSO_PKT_SIZE)
                features &= ~(NETIF_F_TSO | NETIF_F_TSO6);

        return features;
}

static void alx_netif_stop(struct alx_priv *alx)
{
        int i;

        netif_trans_update(alx->dev);
        if (netif_carrier_ok(alx->dev)) {
                netif_carrier_off(alx->dev);
                netif_tx_disable(alx->dev);
                for (i = 0; i < alx->num_napi; i++)
                        napi_disable(&alx->qnapi[i]->napi);
        }
}

static void alx_halt(struct alx_priv *alx)
{
        struct alx_hw *hw = &alx->hw;

        alx_netif_stop(alx);
        hw->link_speed = SPEED_UNKNOWN;
        hw->duplex = DUPLEX_UNKNOWN;

        alx_reset_mac(hw);

        /* disable l0s/l1 */
        alx_enable_aspm(hw, false, false);
        alx_irq_disable(alx);
        alx_free_buffers(alx);
}

static void alx_configure(struct alx_priv *alx)
{
        struct alx_hw *hw = &alx->hw;

        alx_configure_basic(hw);
        alx_disable_rss(hw);
        __alx_set_rx_mode(alx->dev);

        alx_write_mem32(hw, ALX_MAC_CTRL, hw->rx_ctrl);
}

static void alx_activate(struct alx_priv *alx)
{
        /* hardware setting lost, restore it */
        alx_reinit_rings(alx);
        alx_configure(alx);

        /* clear old interrupts */
        alx_write_mem32(&alx->hw, ALX_ISR, ~(u32)ALX_ISR_DIS);

        alx_irq_enable(alx);

        alx_schedule_link_check(alx);
}

static void alx_reinit(struct alx_priv *alx)
{
        ASSERT_RTNL();

        alx_halt(alx);
        alx_activate(alx);
}

static int alx_change_mtu(struct net_device *netdev, int mtu)
{
        struct alx_priv *alx = netdev_priv(netdev);
        int max_frame = ALX_MAX_FRAME_LEN(mtu);

        if ((max_frame < ALX_MIN_FRAME_SIZE) ||
            (max_frame > ALX_MAX_FRAME_SIZE))
                return -EINVAL;

        if (netdev->mtu == mtu)
                return 0;

        netdev->mtu = mtu;
        alx->hw.mtu = mtu;
        alx->rxbuf_size = max(max_frame, ALX_DEF_RXBUF_SIZE);
        netdev_update_features(netdev);
        if (netif_running(netdev))
                alx_reinit(alx);
        return 0;
}

static void alx_netif_start(struct alx_priv *alx)
{
        int i;

        netif_tx_wake_all_queues(alx->dev);
        for (i = 0; i < alx->num_napi; i++)
                napi_enable(&alx->qnapi[i]->napi);
        netif_carrier_on(alx->dev);
}

static int __alx_open(struct alx_priv *alx, bool resume)
{
        int err;

        alx_init_intr(alx, msix);

        if (!resume)
                netif_carrier_off(alx->dev);

        err = alx_alloc_napis(alx);
        if (err)
                goto out_disable_adv_intr;

        err = alx_alloc_rings(alx);
        if (err)
                goto out_free_rings;

        alx_configure(alx);

        err = alx_request_irq(alx);
        if (err)
                goto out_free_rings;

        /* must be called after alx_request_irq because the chip stops working
         * if we copy the dma addresses in alx_init_ring_ptrs twice when
         * requesting msi-x interrupts failed
         */
        alx_reinit_rings(alx);

        netif_set_real_num_tx_queues(alx->dev, alx->num_txq);
        netif_set_real_num_rx_queues(alx->dev, alx->num_rxq);

        /* clear old interrupts */
        alx_write_mem32(&alx->hw, ALX_ISR, ~(u32)ALX_ISR_DIS);

        alx_irq_enable(alx);

        if (!resume)
                netif_tx_start_all_queues(alx->dev);

        alx_schedule_link_check(alx);
        return 0;

out_free_rings:
        alx_free_rings(alx);
        alx_free_napis(alx);
out_disable_adv_intr:
        alx_disable_advanced_intr(alx);
        return err;
}

static void __alx_stop(struct alx_priv *alx)
{
        alx_halt(alx);
        alx_free_irq(alx);
        alx_free_rings(alx);
        alx_free_napis(alx);
}

static const char *alx_speed_desc(struct alx_hw *hw)
{
        switch (alx_speed_to_ethadv(hw->link_speed, hw->duplex)) {
        case ADVERTISED_1000baseT_Full:
                return "1 Gbps Full";
        case ADVERTISED_100baseT_Full:
                return "100 Mbps Full";
        case ADVERTISED_100baseT_Half:
                return "100 Mbps Half";
        case ADVERTISED_10baseT_Full:
                return "10 Mbps Full";
        case ADVERTISED_10baseT_Half:
                return "10 Mbps Half";
        default:
                return "Unknown speed";
        }
}

static void alx_check_link(struct alx_priv *alx)
{
        struct alx_hw *hw = &alx->hw;
        unsigned long flags;
        int old_speed;
        u8 old_duplex;
        int err;

        /* clear PHY internal interrupt status, otherwise the main
         * interrupt status will be asserted forever
         */
        alx_clear_phy_intr(hw);

        old_speed = hw->link_speed;
        old_duplex = hw->duplex;
        err = alx_read_phy_link(hw);
        if (err < 0)
                goto reset;

        spin_lock_irqsave(&alx->irq_lock, flags);
        alx->int_mask |= ALX_ISR_PHY;
        alx_write_mem32(hw, ALX_IMR, alx->int_mask);
        spin_unlock_irqrestore(&alx->irq_lock, flags);

        if (old_speed == hw->link_speed)
                return;

        if (hw->link_speed != SPEED_UNKNOWN) {
                netif_info(alx, link, alx->dev,
                           "NIC Up: %s\n", alx_speed_desc(hw));
                alx_post_phy_link(hw);
                alx_enable_aspm(hw, true, true);
                alx_start_mac(hw);

                if (old_speed == SPEED_UNKNOWN)
                        alx_netif_start(alx);
        } else {
                /* link is now down */
                alx_netif_stop(alx);
                netif_info(alx, link, alx->dev, "Link Down\n");
                err = alx_reset_mac(hw);
                if (err)
                        goto reset;
                alx_irq_disable(alx);

                /* MAC reset causes all HW settings to be lost, restore all */
                err = alx_reinit_rings(alx);
                if (err)
                        goto reset;
                alx_configure(alx);
                alx_enable_aspm(hw, false, true);
                alx_post_phy_link(hw);
                alx_irq_enable(alx);
        }

        return;

reset:
        alx_schedule_reset(alx);
}

static int alx_open(struct net_device *netdev)
{
        return __alx_open(netdev_priv(netdev), false);
}

static int alx_stop(struct net_device *netdev)
{
        __alx_stop(netdev_priv(netdev));
        return 0;
}

static void alx_link_check(struct work_struct *work)
{
        struct alx_priv *alx;

        alx = container_of(work, struct alx_priv, link_check_wk);

        rtnl_lock();
        alx_check_link(alx);
        rtnl_unlock();
}

static void alx_reset(struct work_struct *work)
{
        struct alx_priv *alx = container_of(work, struct alx_priv, reset_wk);

        rtnl_lock();
        alx_reinit(alx);
        rtnl_unlock();
}

static int alx_tpd_req(struct sk_buff *skb)
{
        int num;

        num = skb_shinfo(skb)->nr_frags + 1;
        /* we need one extra descriptor for LSOv2 */
        if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
                num++;

        return num;
}

static int alx_tx_csum(struct sk_buff *skb, struct alx_txd *first)
{
        u8 cso, css;

        if (skb->ip_summed != CHECKSUM_PARTIAL)
                return 0;

        cso = skb_checksum_start_offset(skb);
        if (cso & 1)
                return -EINVAL;

        css = cso + skb->csum_offset;
        first->word1 |= cpu_to_le32((cso >> 1) << TPD_CXSUMSTART_SHIFT);
        first->word1 |= cpu_to_le32((css >> 1) << TPD_CXSUMOFFSET_SHIFT);
        first->word1 |= cpu_to_le32(1 << TPD_CXSUM_EN_SHIFT);

        return 0;
}

static int alx_tso(struct sk_buff *skb, struct alx_txd *first)
{
        int err;

        if (skb->ip_summed != CHECKSUM_PARTIAL)
                return 0;

        if (!skb_is_gso(skb))
                return 0;

        err = skb_cow_head(skb, 0);
        if (err < 0)
                return err;

        if (skb->protocol == htons(ETH_P_IP)) {
                struct iphdr *iph = ip_hdr(skb);

                iph->check = 0;
                tcp_hdr(skb)->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
                                                         0, IPPROTO_TCP, 0);
                first->word1 |= 1 << TPD_IPV4_SHIFT;
        } else if (skb_is_gso_v6(skb)) {
                ipv6_hdr(skb)->payload_len = 0;
                tcp_hdr(skb)->check = ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
                                                       &ipv6_hdr(skb)->daddr,
                                                       0, IPPROTO_TCP, 0);
                /* LSOv2: the first TPD only provides the packet length */
                first->adrl.l.pkt_len = skb->len;
                first->word1 |= 1 << TPD_LSO_V2_SHIFT;
        }

        first->word1 |= 1 << TPD_LSO_EN_SHIFT;
        first->word1 |= (skb_transport_offset(skb) &
                         TPD_L4HDROFFSET_MASK) << TPD_L4HDROFFSET_SHIFT;
        first->word1 |= (skb_shinfo(skb)->gso_size &
                         TPD_MSS_MASK) << TPD_MSS_SHIFT;
        return 1;
}

static int alx_map_tx_skb(struct alx_tx_queue *txq, struct sk_buff *skb)
{
        struct alx_txd *tpd, *first_tpd;
        dma_addr_t dma;
        int maplen, f, first_idx = txq->write_idx;

        first_tpd = &txq->tpd[txq->write_idx];
        tpd = first_tpd;

        if (tpd->word1 & (1 << TPD_LSO_V2_SHIFT)) {
                if (++txq->write_idx == txq->count)
                        txq->write_idx = 0;

                tpd = &txq->tpd[txq->write_idx];
                tpd->len = first_tpd->len;
                tpd->vlan_tag = first_tpd->vlan_tag;
                tpd->word1 = first_tpd->word1;
        }

        maplen = skb_headlen(skb);
        dma = dma_map_single(txq->dev, skb->data, maplen,
                             DMA_TO_DEVICE);
        if (dma_mapping_error(txq->dev, dma))
                goto err_dma;

        dma_unmap_len_set(&txq->bufs[txq->write_idx], size, maplen);
        dma_unmap_addr_set(&txq->bufs[txq->write_idx], dma, dma);

        tpd->adrl.addr = cpu_to_le64(dma);
        tpd->len = cpu_to_le16(maplen);

        for (f = 0; f < skb_shinfo(skb)->nr_frags; f++) {
                struct skb_frag_struct *frag;

                frag = &skb_shinfo(skb)->frags[f];

                if (++txq->write_idx == txq->count)
                        txq->write_idx = 0;
                tpd = &txq->tpd[txq->write_idx];

                tpd->word1 = first_tpd->word1;

                maplen = skb_frag_size(frag);
                dma = skb_frag_dma_map(txq->dev, frag, 0,
                                       maplen, DMA_TO_DEVICE);
                if (dma_mapping_error(txq->dev, dma))
                        goto err_dma;
                dma_unmap_len_set(&txq->bufs[txq->write_idx], size, maplen);
                dma_unmap_addr_set(&txq->bufs[txq->write_idx], dma, dma);

                tpd->adrl.addr = cpu_to_le64(dma);
                tpd->len = cpu_to_le16(maplen);
        }

        /* last TPD, set EOP flag and store skb */
        tpd->word1 |= cpu_to_le32(1 << TPD_EOP_SHIFT);
        txq->bufs[txq->write_idx].skb = skb;

        if (++txq->write_idx == txq->count)
                txq->write_idx = 0;

        return 0;

err_dma:
        f = first_idx;
        while (f != txq->write_idx) {
                alx_free_txbuf(txq, f);
                if (++f == txq->count)
                        f = 0;
        }
        return -ENOMEM;
}

static netdev_tx_t alx_start_xmit_ring(struct sk_buff *skb,
                                       struct alx_tx_queue *txq)
{
        struct alx_priv *alx;
        struct alx_txd *first;
        int tso;

        alx = netdev_priv(txq->netdev);

        if (alx_tpd_avail(txq) < alx_tpd_req(skb)) {
                netif_tx_stop_queue(alx_get_tx_queue(txq));
                goto drop;
        }

        first = &txq->tpd[txq->write_idx];
        memset(first, 0, sizeof(*first));

        tso = alx_tso(skb, first);
        if (tso < 0)
                goto drop;
        else if (!tso && alx_tx_csum(skb, first))
                goto drop;

        if (alx_map_tx_skb(txq, skb) < 0)
                goto drop;

        netdev_tx_sent_queue(alx_get_tx_queue(txq), skb->len);

        /* flush updates before updating hardware */
        wmb();
        alx_write_mem16(&alx->hw, txq->p_reg, txq->write_idx);

        if (alx_tpd_avail(txq) < txq->count / 8)
                netif_tx_stop_queue(alx_get_tx_queue(txq));

        return NETDEV_TX_OK;

drop:
        dev_kfree_skb_any(skb);
        return NETDEV_TX_OK;
}

static netdev_tx_t alx_start_xmit(struct sk_buff *skb,
                                  struct net_device *netdev)
{
        struct alx_priv *alx = netdev_priv(netdev);
        return alx_start_xmit_ring(skb, alx_tx_queue_mapping(alx, skb));
}

static void alx_tx_timeout(struct net_device *dev)
{
        struct alx_priv *alx = netdev_priv(dev);

        alx_schedule_reset(alx);
}

static int alx_mdio_read(struct net_device *netdev,
                         int prtad, int devad, u16 addr)
{
        struct alx_priv *alx = netdev_priv(netdev);
        struct alx_hw *hw = &alx->hw;
        u16 val;
        int err;

        if (prtad != hw->mdio.prtad)
                return -EINVAL;

        if (devad == MDIO_DEVAD_NONE)
                err = alx_read_phy_reg(hw, addr, &val);
        else
                err = alx_read_phy_ext(hw, devad, addr, &val);

        if (err)
                return err;
        return val;
}

static int alx_mdio_write(struct net_device *netdev,
                          int prtad, int devad, u16 addr, u16 val)
{
        struct alx_priv *alx = netdev_priv(netdev);
        struct alx_hw *hw = &alx->hw;

        if (prtad != hw->mdio.prtad)
                return -EINVAL;

        if (devad == MDIO_DEVAD_NONE)
                return alx_write_phy_reg(hw, addr, val);

        return alx_write_phy_ext(hw, devad, addr, val);
}

static int alx_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd)
{
        struct alx_priv *alx = netdev_priv(netdev);

        if (!netif_running(netdev))
                return -EAGAIN;

        return mdio_mii_ioctl(&alx->hw.mdio, if_mii(ifr), cmd);
}

#ifdef CONFIG_NET_POLL_CONTROLLER
static void alx_poll_controller(struct net_device *netdev)
{
        struct alx_priv *alx = netdev_priv(netdev);
        int i;

        if (alx->flags & ALX_FLAG_USING_MSIX) {
                alx_intr_msix_misc(0, alx);
                for (i = 0; i < alx->num_txq; i++)
                        alx_intr_msix_ring(0, alx->qnapi[i]);
        } else if (alx->flags & ALX_FLAG_USING_MSI)
                alx_intr_msi(0, alx);
        else
                alx_intr_legacy(0, alx);
}
#endif

static void alx_get_stats64(struct net_device *dev,
                            struct rtnl_link_stats64 *net_stats)
{
        struct alx_priv *alx = netdev_priv(dev);
        struct alx_hw_stats *hw_stats = &alx->hw.stats;

        spin_lock(&alx->stats_lock);

        alx_update_hw_stats(&alx->hw);

        net_stats->tx_bytes   = hw_stats->tx_byte_cnt;
        net_stats->rx_bytes   = hw_stats->rx_byte_cnt;
        net_stats->multicast  = hw_stats->rx_mcast;
        net_stats->collisions = hw_stats->tx_single_col +
                                hw_stats->tx_multi_col +
                                hw_stats->tx_late_col +
                                hw_stats->tx_abort_col;

        net_stats->rx_errors  = hw_stats->rx_frag +
                                hw_stats->rx_fcs_err +
                                hw_stats->rx_len_err +
                                hw_stats->rx_ov_sz +
                                hw_stats->rx_ov_rrd +
                                hw_stats->rx_align_err +
                                hw_stats->rx_ov_rxf;

        net_stats->rx_fifo_errors   = hw_stats->rx_ov_rxf;
        net_stats->rx_length_errors = hw_stats->rx_len_err;
        net_stats->rx_crc_errors    = hw_stats->rx_fcs_err;
        net_stats->rx_frame_errors  = hw_stats->rx_align_err;
        net_stats->rx_dropped       = hw_stats->rx_ov_rrd;

        net_stats->tx_errors = hw_stats->tx_late_col +
                               hw_stats->tx_abort_col +
                               hw_stats->tx_underrun +
                               hw_stats->tx_trunc;

        net_stats->tx_aborted_errors = hw_stats->tx_abort_col;
        net_stats->tx_fifo_errors    = hw_stats->tx_underrun;
        net_stats->tx_window_errors  = hw_stats->tx_late_col;

        net_stats->tx_packets = hw_stats->tx_ok + net_stats->tx_errors;
        net_stats->rx_packets = hw_stats->rx_ok + net_stats->rx_errors;

        spin_unlock(&alx->stats_lock);
}

static const struct net_device_ops alx_netdev_ops = {
        .ndo_open               = alx_open,
        .ndo_stop               = alx_stop,
        .ndo_start_xmit         = alx_start_xmit,
        .ndo_get_stats64        = alx_get_stats64,
        .ndo_set_rx_mode        = alx_set_rx_mode,
        .ndo_validate_addr      = eth_validate_addr,
        .ndo_set_mac_address    = alx_set_mac_address,
        .ndo_change_mtu_rh74    = alx_change_mtu,
        .ndo_do_ioctl           = alx_ioctl,
        .ndo_tx_timeout         = alx_tx_timeout,
        .ndo_fix_features       = alx_fix_features,
#ifdef CONFIG_NET_POLL_CONTROLLER
        .ndo_poll_controller    = alx_poll_controller,
#endif
};

static int alx_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
{
        struct net_device *netdev;
        struct alx_priv *alx;
        struct alx_hw *hw;
        bool phy_configured;
        int bars, err;

        err = pci_enable_device_mem(pdev);
        if (err)
                return err;

        /* The alx chip can DMA to 64-bit addresses, but it uses a single
         * shared register for the high 32 bits, so only a single, aligned,
         * 4 GB physical address range can be used for descriptors.
         */
        if (!dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64))) {
                dev_dbg(&pdev->dev, "DMA to 64-BIT addresses\n");
        } else {
                err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
                if (err) {
                        dev_err(&pdev->dev, "No usable DMA config, aborting\n");
                        goto out_pci_disable;
                }
        }

        bars = pci_select_bars(pdev, IORESOURCE_MEM);
        err = pci_request_selected_regions(pdev, bars, alx_drv_name);
        if (err) {
                dev_err(&pdev->dev,
                        "pci_request_selected_regions failed(bars:%d)\n", bars);
                goto out_pci_disable;
        }

        pci_enable_pcie_error_reporting(pdev);
        pci_set_master(pdev);

        if (!pdev->pm_cap) {
                dev_err(&pdev->dev,
                        "Can't find power management capability, aborting\n");
                err = -EIO;
                goto out_pci_release;
        }

        netdev = alloc_etherdev_mqs(sizeof(*alx),
                                    ALX_MAX_TX_QUEUES, 1);
        if (!netdev) {
                err = -ENOMEM;
                goto out_pci_release;
        }

        SET_NETDEV_DEV(netdev, &pdev->dev);
        alx = netdev_priv(netdev);
        spin_lock_init(&alx->hw.mdio_lock);
        spin_lock_init(&alx->irq_lock);
        spin_lock_init(&alx->stats_lock);
        alx->dev = netdev;
        alx->hw.pdev = pdev;
        alx->msg_enable = NETIF_MSG_LINK | NETIF_MSG_HW | NETIF_MSG_IFUP |
                          NETIF_MSG_TX_ERR | NETIF_MSG_RX_ERR | NETIF_MSG_WOL;
        hw = &alx->hw;
        pci_set_drvdata(pdev, alx);

        hw->hw_addr = pci_ioremap_bar(pdev, 0);
        if (!hw->hw_addr) {
                dev_err(&pdev->dev, "cannot map device registers\n");
                err = -EIO;
                goto out_free_netdev;
        }

        netdev->netdev_ops = &alx_netdev_ops;
        netdev->ethtool_ops = &alx_ethtool_ops;
        netdev->irq = pdev->irq;
        netdev->watchdog_timeo = ALX_WATCHDOG_TIME;

        if (ent->driver_data & ALX_DEV_QUIRK_MSI_INTX_DISABLE_BUG)
                pdev->dev_flags |= PCI_DEV_FLAGS_MSI_INTX_DISABLE_BUG;

        err = alx_init_sw(alx);
        if (err) {
                dev_err(&pdev->dev, "net device private data init failed\n");
                goto out_unmap;
        }

        alx_reset_pcie(hw);

        phy_configured = alx_phy_configured(hw);

        if (!phy_configured)
                alx_reset_phy(hw);

        err = alx_reset_mac(hw);
        if (err) {
                dev_err(&pdev->dev, "MAC Reset failed, error = %d\n", err);
                goto out_unmap;
        }

        /* setup link to put it in a known good starting state */
        if (!phy_configured) {
                err = alx_setup_speed_duplex(hw, hw->adv_cfg, hw->flowctrl);
                if (err) {
                        dev_err(&pdev->dev,
                                "failed to configure PHY speed/duplex (err=%d)\n",
                                err);
                        goto out_unmap;
                }
        }

        netdev->hw_features = NETIF_F_SG |
                              NETIF_F_HW_CSUM |
                              NETIF_F_TSO |
                              NETIF_F_TSO6;

        if (alx_get_perm_macaddr(hw, hw->perm_addr)) {
                dev_warn(&pdev->dev,
                         "Invalid permanent address programmed, using random one\n");
                eth_hw_addr_random(netdev);
                memcpy(hw->perm_addr, netdev->dev_addr, netdev->addr_len);
        }

        memcpy(hw->mac_addr, hw->perm_addr, ETH_ALEN);
        memcpy(netdev->dev_addr, hw->mac_addr, ETH_ALEN);
        memcpy(netdev->perm_addr, hw->perm_addr, ETH_ALEN);

        hw->mdio.prtad = 0;
        hw->mdio.mmds = 0;
        hw->mdio.dev = netdev;
        hw->mdio.mode_support = MDIO_SUPPORTS_C45 |
                                MDIO_SUPPORTS_C22 |
                                MDIO_EMULATE_C22;
        hw->mdio.mdio_read = alx_mdio_read;
        hw->mdio.mdio_write = alx_mdio_write;

        if (!alx_get_phy_info(hw)) {
                dev_err(&pdev->dev, "failed to identify PHY\n");
                err = -EIO;
                goto out_unmap;
        }

        INIT_WORK(&alx->link_check_wk, alx_link_check);
        INIT_WORK(&alx->reset_wk, alx_reset);
        netif_carrier_off(netdev);

        err = register_netdev(netdev);
        if (err) {
                dev_err(&pdev->dev, "register netdevice failed\n");
                goto out_unmap;
        }

        netdev_info(netdev,
                    "Qualcomm Atheros AR816x/AR817x Ethernet [%pM]\n",
                    netdev->dev_addr);

        return 0;

out_unmap:
        iounmap(hw->hw_addr);
out_free_netdev:
        free_netdev(netdev);
out_pci_release:
        pci_release_selected_regions(pdev, bars);
out_pci_disable:
        pci_disable_device(pdev);
        return err;
}

static void alx_remove(struct pci_dev *pdev)
{
        struct alx_priv *alx = pci_get_drvdata(pdev);
        struct alx_hw *hw = &alx->hw;

        cancel_work_sync(&alx->link_check_wk);
        cancel_work_sync(&alx->reset_wk);

        /* restore permanent mac address */
        alx_set_macaddr(hw, hw->perm_addr);

        unregister_netdev(alx->dev);
        iounmap(hw->hw_addr);
        pci_release_selected_regions(pdev,
                                     pci_select_bars(pdev, IORESOURCE_MEM));

        pci_disable_pcie_error_reporting(pdev);
        pci_disable_device(pdev);

        free_netdev(alx->dev);
}

#ifdef CONFIG_PM_SLEEP
static int alx_suspend(struct device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        struct alx_priv *alx = pci_get_drvdata(pdev);

        if (!netif_running(alx->dev))
                return 0;
        netif_device_detach(alx->dev);
        __alx_stop(alx);
        return 0;
}

static int alx_resume(struct device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        struct alx_priv *alx = pci_get_drvdata(pdev);
        struct alx_hw *hw = &alx->hw;

        alx_reset_phy(hw);

        if (!netif_running(alx->dev))
                return 0;
        netif_device_attach(alx->dev);
        return __alx_open(alx, true);
}

static SIMPLE_DEV_PM_OPS(alx_pm_ops, alx_suspend, alx_resume);
#define ALX_PM_OPS      (&alx_pm_ops)
#else
#define ALX_PM_OPS      NULL
#endif


static pci_ers_result_t alx_pci_error_detected(struct pci_dev *pdev,
                                               pci_channel_state_t state)
{
        struct alx_priv *alx = pci_get_drvdata(pdev);
        struct net_device *netdev = alx->dev;
        pci_ers_result_t rc = PCI_ERS_RESULT_NEED_RESET;

        dev_info(&pdev->dev, "pci error detected\n");

        rtnl_lock();

        if (netif_running(netdev)) {
                netif_device_detach(netdev);
                alx_halt(alx);
        }

        if (state == pci_channel_io_perm_failure)
                rc = PCI_ERS_RESULT_DISCONNECT;
        else
                pci_disable_device(pdev);

        rtnl_unlock();

        return rc;
}

static pci_ers_result_t alx_pci_error_slot_reset(struct pci_dev *pdev)
{
        struct alx_priv *alx = pci_get_drvdata(pdev);
        struct alx_hw *hw = &alx->hw;
        pci_ers_result_t rc = PCI_ERS_RESULT_DISCONNECT;

        dev_info(&pdev->dev, "pci error slot reset\n");

        rtnl_lock();

        if (pci_enable_device(pdev)) {
                dev_err(&pdev->dev, "Failed to re-enable PCI device after reset\n");
                goto out;
        }

        pci_set_master(pdev);

        alx_reset_pcie(hw);
        if (!alx_reset_mac(hw))
                rc = PCI_ERS_RESULT_RECOVERED;
out:
        pci_cleanup_aer_uncorrect_error_status(pdev);

        rtnl_unlock();

        return rc;
}

static void alx_pci_error_resume(struct pci_dev *pdev)
{

        struct alx_priv *alx = pci_get_drvdata(pdev);
        struct net_device *netdev = alx->dev;

        dev_info(&pdev->dev, "pci error resume\n");

        rtnl_lock();

        if (netif_running(netdev)) {
                alx_activate(alx);
                netif_device_attach(netdev);
        }

        rtnl_unlock();
}

static const struct pci_error_handlers alx_err_handlers = {
        .error_detected = alx_pci_error_detected,
        .slot_reset     = alx_pci_error_slot_reset,
        .resume         = alx_pci_error_resume,
};

static const struct pci_device_id alx_pci_tbl[] = {
        { PCI_VDEVICE(ATTANSIC, ALX_DEV_ID_AR8161),
          .driver_data = ALX_DEV_QUIRK_MSI_INTX_DISABLE_BUG },
        { PCI_VDEVICE(ATTANSIC, ALX_DEV_ID_E2200),
          .driver_data = ALX_DEV_QUIRK_MSI_INTX_DISABLE_BUG },
        { PCI_VDEVICE(ATTANSIC, ALX_DEV_ID_E2400),
          .driver_data = ALX_DEV_QUIRK_MSI_INTX_DISABLE_BUG },
        { PCI_VDEVICE(ATTANSIC, ALX_DEV_ID_E2500),
          .driver_data = ALX_DEV_QUIRK_MSI_INTX_DISABLE_BUG },
        { PCI_VDEVICE(ATTANSIC, ALX_DEV_ID_AR8162),
          .driver_data = ALX_DEV_QUIRK_MSI_INTX_DISABLE_BUG },
        { PCI_VDEVICE(ATTANSIC, ALX_DEV_ID_AR8171) },
        { PCI_VDEVICE(ATTANSIC, ALX_DEV_ID_AR8172) },
        {}
};

static struct pci_driver alx_driver = {
        .name        = alx_drv_name,
        .id_table    = alx_pci_tbl,
        .probe       = alx_probe,
        .remove      = alx_remove,
        .err_handler = &alx_err_handlers,
        .driver.pm   = ALX_PM_OPS,
};

module_pci_driver(alx_driver);
MODULE_DEVICE_TABLE(pci, alx_pci_tbl);
MODULE_AUTHOR("Johannes Berg <johannes@sipsolutions.net>");
MODULE_AUTHOR("Qualcomm Corporation, <nic-devel@qualcomm.com>");
MODULE_DESCRIPTION(
        "Qualcomm Atheros(R) AR816x/AR817x PCI-E Ethernet Network Driver");
MODULE_LICENSE("GPL");