// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2010 ASIX Electronics Corporation
 * Copyright (c) 2020 Samsung Electronics Co., Ltd.
 *
 * ASIX AX88796C SPI Fast Ethernet Linux driver
 */

#define pr_fmt(fmt)     "ax88796c: " fmt

#include "ax88796c_main.h"
#include "ax88796c_ioctl.h"

#include <linux/bitmap.h>
#include <linux/etherdevice.h>
#include <linux/iopoll.h>
#include <linux/lockdep.h>
#include <linux/mdio.h>
#include <linux/minmax.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/of.h>
#include <linux/phy.h>
#include <linux/skbuff.h>
#include <linux/spi/spi.h>

static int comp = IS_ENABLED(CONFIG_SPI_AX88796C_COMPRESSION);
static int msg_enable = NETIF_MSG_PROBE |
                        NETIF_MSG_LINK |
                        NETIF_MSG_RX_ERR |
                        NETIF_MSG_TX_ERR;

static const char *no_regs_list = "80018001,e1918001,8001a001,fc0d0000";
unsigned long ax88796c_no_regs_mask[AX88796C_REGDUMP_LEN / (sizeof(unsigned long) * 8)];

module_param(msg_enable, int, 0444);
MODULE_PARM_DESC(msg_enable, "Message mask (see linux/netdevice.h for bitmap)");

static int ax88796c_soft_reset(struct ax88796c_device *ax_local)
{
        u16 temp;
        int ret;

        lockdep_assert_held(&ax_local->spi_lock);

        AX_WRITE(&ax_local->ax_spi, PSR_RESET, P0_PSR);
        AX_WRITE(&ax_local->ax_spi, PSR_RESET_CLR, P0_PSR);

        ret = read_poll_timeout(AX_READ, ret,
                                (ret & PSR_DEV_READY),
                                0, jiffies_to_usecs(160 * HZ / 1000), false,
                                &ax_local->ax_spi, P0_PSR);
        if (ret)
                return ret;

        temp = AX_READ(&ax_local->ax_spi, P4_SPICR);
        if (ax_local->priv_flags & AX_CAP_COMP) {
                AX_WRITE(&ax_local->ax_spi,
                         (temp | SPICR_RCEN | SPICR_QCEN), P4_SPICR);
                ax_local->ax_spi.comp = 1;
        } else {
                AX_WRITE(&ax_local->ax_spi,
                         (temp & ~(SPICR_RCEN | SPICR_QCEN)), P4_SPICR);
                ax_local->ax_spi.comp = 0;
        }

        return 0;
}

static int ax88796c_reload_eeprom(struct ax88796c_device *ax_local)
{
        int ret;

        lockdep_assert_held(&ax_local->spi_lock);

        AX_WRITE(&ax_local->ax_spi, EECR_RELOAD, P3_EECR);

        ret = read_poll_timeout(AX_READ, ret,
                                (ret & PSR_DEV_READY),
                                0, jiffies_to_usecs(2 * HZ / 1000), false,
                                &ax_local->ax_spi, P0_PSR);
        if (ret) {
                dev_err(&ax_local->spi->dev,
                        "timeout waiting for reload eeprom\n");
                return ret;
        }

        return 0;
}

static void ax88796c_set_hw_multicast(struct net_device *ndev)
{
        struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
        int mc_count = netdev_mc_count(ndev);
        u16 rx_ctl = RXCR_AB;

        lockdep_assert_held(&ax_local->spi_lock);

        memset(ax_local->multi_filter, 0, AX_MCAST_FILTER_SIZE);

        if (ndev->flags & IFF_PROMISC) {
                rx_ctl |= RXCR_PRO;

        } else if (ndev->flags & IFF_ALLMULTI || mc_count > AX_MAX_MCAST) {
                rx_ctl |= RXCR_AMALL;

        } else if (mc_count == 0) {
                /* just broadcast and directed */
        } else {
                u32 crc_bits;
                int i;
                struct netdev_hw_addr *ha;

                netdev_for_each_mc_addr(ha, ndev) {
                        crc_bits = ether_crc(ETH_ALEN, ha->addr);
                        ax_local->multi_filter[crc_bits >> 29] |=
                                                (1 << ((crc_bits >> 26) & 7));
                }

                for (i = 0; i < 4; i++) {
                        AX_WRITE(&ax_local->ax_spi,
                                 ((ax_local->multi_filter[i * 2 + 1] << 8) |
                                  ax_local->multi_filter[i * 2]), P3_MFAR(i));
                }
        }

        AX_WRITE(&ax_local->ax_spi, rx_ctl, P2_RXCR);
}

static void ax88796c_set_mac_addr(struct net_device *ndev)
{
        struct ax88796c_device *ax_local = to_ax88796c_device(ndev);

        lockdep_assert_held(&ax_local->spi_lock);

        AX_WRITE(&ax_local->ax_spi, ((u16)(ndev->dev_addr[4] << 8) |
                        (u16)ndev->dev_addr[5]), P3_MACASR0);
        AX_WRITE(&ax_local->ax_spi, ((u16)(ndev->dev_addr[2] << 8) |
                        (u16)ndev->dev_addr[3]), P3_MACASR1);
        AX_WRITE(&ax_local->ax_spi, ((u16)(ndev->dev_addr[0] << 8) |
                        (u16)ndev->dev_addr[1]), P3_MACASR2);
}

static void ax88796c_load_mac_addr(struct net_device *ndev)
{
        struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
        u8 addr[ETH_ALEN];
        u16 temp;

        lockdep_assert_held(&ax_local->spi_lock);

        /* Try the device tree first */
        if (!platform_get_ethdev_address(&ax_local->spi->dev, ndev) &&
            is_valid_ether_addr(ndev->dev_addr)) {
                if (netif_msg_probe(ax_local))
                        dev_info(&ax_local->spi->dev,
                                 "MAC address read from device tree\n");
                return;
        }

        /* Read the MAC address from AX88796C */
        temp = AX_READ(&ax_local->ax_spi, P3_MACASR0);
        addr[5] = (u8)temp;
        addr[4] = (u8)(temp >> 8);

        temp = AX_READ(&ax_local->ax_spi, P3_MACASR1);
        addr[3] = (u8)temp;
        addr[2] = (u8)(temp >> 8);

        temp = AX_READ(&ax_local->ax_spi, P3_MACASR2);
        addr[1] = (u8)temp;
        addr[0] = (u8)(temp >> 8);

        if (is_valid_ether_addr(addr)) {
                eth_hw_addr_set(ndev, addr);
                if (netif_msg_probe(ax_local))
                        dev_info(&ax_local->spi->dev,
                                 "MAC address read from ASIX chip\n");
                return;
        }

        /* Use random address if none found */
        if (netif_msg_probe(ax_local))
                dev_info(&ax_local->spi->dev, "Use random MAC address\n");
        eth_hw_addr_random(ndev);
}

static void ax88796c_proc_tx_hdr(struct tx_pkt_info *info, u8 ip_summed)
{
        u16 pkt_len_bar = (~info->pkt_len & TX_HDR_SOP_PKTLENBAR);

        /* Prepare SOP header */
        info->sop.flags_len = info->pkt_len |
                ((ip_summed == CHECKSUM_NONE) ||
                 (ip_summed == CHECKSUM_UNNECESSARY) ? TX_HDR_SOP_DICF : 0);

        info->sop.seq_lenbar = ((info->seq_num << 11) & TX_HDR_SOP_SEQNUM)
                                | pkt_len_bar;
        cpu_to_be16s(&info->sop.flags_len);
        cpu_to_be16s(&info->sop.seq_lenbar);

        /* Prepare Segment header */
        info->seg.flags_seqnum_seglen = TX_HDR_SEG_FS | TX_HDR_SEG_LS
                                                | info->pkt_len;

        info->seg.eo_so_seglenbar = pkt_len_bar;

        cpu_to_be16s(&info->seg.flags_seqnum_seglen);
        cpu_to_be16s(&info->seg.eo_so_seglenbar);

        /* Prepare EOP header */
        info->eop.seq_len = ((info->seq_num << 11) &
                             TX_HDR_EOP_SEQNUM) | info->pkt_len;
        info->eop.seqbar_lenbar = ((~info->seq_num << 11) &
                                   TX_HDR_EOP_SEQNUMBAR) | pkt_len_bar;

        cpu_to_be16s(&info->eop.seq_len);
        cpu_to_be16s(&info->eop.seqbar_lenbar);
}

static int
ax88796c_check_free_pages(struct ax88796c_device *ax_local, u8 need_pages)
{
        u8 free_pages;
        u16 tmp;

        lockdep_assert_held(&ax_local->spi_lock);

        free_pages = AX_READ(&ax_local->ax_spi, P0_TFBFCR) & TX_FREEBUF_MASK;
        if (free_pages < need_pages) {
                /* schedule free page interrupt */
                tmp = AX_READ(&ax_local->ax_spi, P0_TFBFCR)
                                & TFBFCR_SCHE_FREE_PAGE;
                AX_WRITE(&ax_local->ax_spi, tmp | TFBFCR_TX_PAGE_SET |
                                TFBFCR_SET_FREE_PAGE(need_pages),
                                P0_TFBFCR);
                return -ENOMEM;
        }

        return 0;
}

static struct sk_buff *
ax88796c_tx_fixup(struct net_device *ndev, struct sk_buff_head *q)
{
        struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
        u8 spi_len = ax_local->ax_spi.comp ? 1 : 4;
        struct sk_buff *skb;
        struct tx_pkt_info info;
        struct skb_data *entry;
        u16 pkt_len;
        u8 padlen, seq_num;
        u8 need_pages;
        int headroom;
        int tailroom;

        if (skb_queue_empty(q))
                return NULL;

        skb = skb_peek(q);
        pkt_len = skb->len;
        need_pages = (pkt_len + TX_OVERHEAD + 127) >> 7;
        if (ax88796c_check_free_pages(ax_local, need_pages) != 0)
                return NULL;

        headroom = skb_headroom(skb);
        tailroom = skb_tailroom(skb);
        padlen = round_up(pkt_len, 4) - pkt_len;
        seq_num = ++ax_local->seq_num & 0x1F;

        info.pkt_len = pkt_len;

        if (skb_cloned(skb) ||
            (headroom < (TX_OVERHEAD + spi_len)) ||
            (tailroom < (padlen + TX_EOP_SIZE))) {
                size_t h = max((TX_OVERHEAD + spi_len) - headroom, 0);
                size_t t = max((padlen + TX_EOP_SIZE) - tailroom, 0);

                if (pskb_expand_head(skb, h, t, GFP_KERNEL))
                        return NULL;
        }

        info.seq_num = seq_num;
        ax88796c_proc_tx_hdr(&info, skb->ip_summed);

        /* SOP and SEG header */
        memcpy(skb_push(skb, TX_OVERHEAD), &info.tx_overhead, TX_OVERHEAD);

        /* Write SPI TXQ header */
        memcpy(skb_push(skb, spi_len), ax88796c_tx_cmd_buf, spi_len);

        /* Make 32-bit alignment */
        skb_put(skb, padlen);

        /* EOP header */
        skb_put_data(skb, &info.eop, TX_EOP_SIZE);

        skb_unlink(skb, q);

        entry = (struct skb_data *)skb->cb;
        memset(entry, 0, sizeof(*entry));
        entry->len = pkt_len;

        if (netif_msg_pktdata(ax_local)) {
                char pfx[IFNAMSIZ + 7];

                snprintf(pfx, sizeof(pfx), "%s:     ", ndev->name);

                netdev_info(ndev, "TX packet len %d, total len %d, seq %d\n",
                            pkt_len, skb->len, seq_num);

                netdev_info(ndev, "  SPI Header:\n");
                print_hex_dump(KERN_INFO, pfx, DUMP_PREFIX_OFFSET, 16, 1,
                               skb->data, 4, 0);

                netdev_info(ndev, "  TX SOP:\n");
                print_hex_dump(KERN_INFO, pfx, DUMP_PREFIX_OFFSET, 16, 1,
                               skb->data + 4, TX_OVERHEAD, 0);

                netdev_info(ndev, "  TX packet:\n");
                print_hex_dump(KERN_INFO, pfx, DUMP_PREFIX_OFFSET, 16, 1,
                               skb->data + 4 + TX_OVERHEAD,
                               skb->len - TX_EOP_SIZE - 4 - TX_OVERHEAD, 0);

                netdev_info(ndev, "  TX EOP:\n");
                print_hex_dump(KERN_INFO, pfx, DUMP_PREFIX_OFFSET, 16, 1,
                               skb->data + skb->len - 4, 4, 0);
        }

        return skb;
}

static int ax88796c_hard_xmit(struct ax88796c_device *ax_local)
{
        struct ax88796c_pcpu_stats *stats;
        struct sk_buff *tx_skb;
        struct skb_data *entry;
        unsigned long flags;

        lockdep_assert_held(&ax_local->spi_lock);

        stats = this_cpu_ptr(ax_local->stats);
        tx_skb = ax88796c_tx_fixup(ax_local->ndev, &ax_local->tx_wait_q);

        if (!tx_skb) {
                this_cpu_inc(ax_local->stats->tx_dropped);
                return 0;
        }
        entry = (struct skb_data *)tx_skb->cb;

        AX_WRITE(&ax_local->ax_spi,
                 (TSNR_TXB_START | TSNR_PKT_CNT(1)), P0_TSNR);

        axspi_write_txq(&ax_local->ax_spi, tx_skb->data, tx_skb->len);

        if (((AX_READ(&ax_local->ax_spi, P0_TSNR) & TXNR_TXB_IDLE) == 0) ||
            ((ISR_TXERR & AX_READ(&ax_local->ax_spi, P0_ISR)) != 0)) {
                /* Ack tx error int */
                AX_WRITE(&ax_local->ax_spi, ISR_TXERR, P0_ISR);

                this_cpu_inc(ax_local->stats->tx_dropped);

                if (net_ratelimit())
                        netif_err(ax_local, tx_err, ax_local->ndev,
                                  "TX FIFO error, re-initialize the TX bridge\n");

                /* Reinitial tx bridge */
                AX_WRITE(&ax_local->ax_spi, TXNR_TXB_REINIT |
                        AX_READ(&ax_local->ax_spi, P0_TSNR), P0_TSNR);
                ax_local->seq_num = 0;
        } else {
                flags = u64_stats_update_begin_irqsave(&stats->syncp);
                u64_stats_inc(&stats->tx_packets);
                u64_stats_add(&stats->tx_bytes, entry->len);
                u64_stats_update_end_irqrestore(&stats->syncp, flags);
        }

        entry->state = tx_done;
        dev_kfree_skb(tx_skb);

        return 1;
}

static netdev_tx_t
ax88796c_start_xmit(struct sk_buff *skb, struct net_device *ndev)
{
        struct ax88796c_device *ax_local = to_ax88796c_device(ndev);

        skb_queue_tail(&ax_local->tx_wait_q, skb);
        if (skb_queue_len(&ax_local->tx_wait_q) > TX_QUEUE_HIGH_WATER)
                netif_stop_queue(ndev);

        set_bit(EVENT_TX, &ax_local->flags);
        schedule_work(&ax_local->ax_work);

        return NETDEV_TX_OK;
}

static void
ax88796c_skb_return(struct ax88796c_device *ax_local,
                    struct sk_buff *skb, struct rx_header *rxhdr)
{
        struct net_device *ndev = ax_local->ndev;
        struct ax88796c_pcpu_stats *stats;
        unsigned long flags;
        int status;

        stats = this_cpu_ptr(ax_local->stats);

        do {
                if (!(ndev->features & NETIF_F_RXCSUM))
                        break;

                /* checksum error bit is set */
                if ((rxhdr->flags & RX_HDR3_L3_ERR) ||
                    (rxhdr->flags & RX_HDR3_L4_ERR))
                        break;

                /* Other types may be indicated by more than one bit. */
                if ((rxhdr->flags & RX_HDR3_L4_TYPE_TCP) ||
                    (rxhdr->flags & RX_HDR3_L4_TYPE_UDP))
                        skb->ip_summed = CHECKSUM_UNNECESSARY;
        } while (0);

        flags = u64_stats_update_begin_irqsave(&stats->syncp);
        u64_stats_inc(&stats->rx_packets);
        u64_stats_add(&stats->rx_bytes, skb->len);
        u64_stats_update_end_irqrestore(&stats->syncp, flags);

        skb->dev = ndev;
        skb->protocol = eth_type_trans(skb, ax_local->ndev);

        netif_info(ax_local, rx_status, ndev, "< rx, len %zu, type 0x%x\n",
                   skb->len + sizeof(struct ethhdr), skb->protocol);

        status = netif_rx(skb);
        if (status != NET_RX_SUCCESS && net_ratelimit())
                netif_info(ax_local, rx_err, ndev,
                           "netif_rx status %d\n", status);
}

static void
ax88796c_rx_fixup(struct ax88796c_device *ax_local, struct sk_buff *rx_skb)
{
        struct rx_header *rxhdr = (struct rx_header *)rx_skb->data;
        struct net_device *ndev = ax_local->ndev;
        u16 len;

        be16_to_cpus(&rxhdr->flags_len);
        be16_to_cpus(&rxhdr->seq_lenbar);
        be16_to_cpus(&rxhdr->flags);

        if ((rxhdr->flags_len & RX_HDR1_PKT_LEN) !=
                         (~rxhdr->seq_lenbar & 0x7FF)) {
                netif_err(ax_local, rx_err, ndev, "Header error\n");

                this_cpu_inc(ax_local->stats->rx_frame_errors);
                kfree_skb(rx_skb);
                return;
        }

        if ((rxhdr->flags_len & RX_HDR1_MII_ERR) ||
            (rxhdr->flags_len & RX_HDR1_CRC_ERR)) {
                netif_err(ax_local, rx_err, ndev, "CRC or MII error\n");

                this_cpu_inc(ax_local->stats->rx_crc_errors);
                kfree_skb(rx_skb);
                return;
        }

        len = rxhdr->flags_len & RX_HDR1_PKT_LEN;
        if (netif_msg_pktdata(ax_local)) {
                char pfx[IFNAMSIZ + 7];

                snprintf(pfx, sizeof(pfx), "%s:     ", ndev->name);
                netdev_info(ndev, "RX data, total len %d, packet len %d\n",
                            rx_skb->len, len);

                netdev_info(ndev, "  Dump RX packet header:");
                print_hex_dump(KERN_INFO, pfx, DUMP_PREFIX_OFFSET, 16, 1,
                               rx_skb->data, sizeof(*rxhdr), 0);

                netdev_info(ndev, "  Dump RX packet:");
                print_hex_dump(KERN_INFO, pfx, DUMP_PREFIX_OFFSET, 16, 1,
                               rx_skb->data + sizeof(*rxhdr), len, 0);
        }

        skb_pull(rx_skb, sizeof(*rxhdr));
        pskb_trim(rx_skb, len);

        ax88796c_skb_return(ax_local, rx_skb, rxhdr);
}

static int ax88796c_receive(struct net_device *ndev)
{
        struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
        struct skb_data *entry;
        u16 w_count, pkt_len;
        struct sk_buff *skb;
        u8 pkt_cnt;

        lockdep_assert_held(&ax_local->spi_lock);

        /* check rx packet and total word count */
        AX_WRITE(&ax_local->ax_spi, AX_READ(&ax_local->ax_spi, P0_RTWCR)
                  | RTWCR_RX_LATCH, P0_RTWCR);

        pkt_cnt = AX_READ(&ax_local->ax_spi, P0_RXBCR2) & RXBCR2_PKT_MASK;
        if (!pkt_cnt)
                return 0;

        pkt_len = AX_READ(&ax_local->ax_spi, P0_RCPHR) & 0x7FF;

        w_count = round_up(pkt_len + 6, 4) >> 1;

        skb = netdev_alloc_skb(ndev, w_count * 2);
        if (!skb) {
                AX_WRITE(&ax_local->ax_spi, RXBCR1_RXB_DISCARD, P0_RXBCR1);
                this_cpu_inc(ax_local->stats->rx_dropped);
                return 0;
        }
        entry = (struct skb_data *)skb->cb;

        AX_WRITE(&ax_local->ax_spi, RXBCR1_RXB_START | w_count, P0_RXBCR1);

        axspi_read_rxq(&ax_local->ax_spi,
                       skb_put(skb, w_count * 2), skb->len);

        /* Check if rx bridge is idle */
        if ((AX_READ(&ax_local->ax_spi, P0_RXBCR2) & RXBCR2_RXB_IDLE) == 0) {
                if (net_ratelimit())
                        netif_err(ax_local, rx_err, ndev,
                                  "Rx Bridge is not idle\n");
                AX_WRITE(&ax_local->ax_spi, RXBCR2_RXB_REINIT, P0_RXBCR2);

                entry->state = rx_err;
        } else {
                entry->state = rx_done;
        }

        AX_WRITE(&ax_local->ax_spi, ISR_RXPKT, P0_ISR);

        ax88796c_rx_fixup(ax_local, skb);

        return 1;
}

static int ax88796c_process_isr(struct ax88796c_device *ax_local)
{
        struct net_device *ndev = ax_local->ndev;
        int todo = 0;
        u16 isr;

        lockdep_assert_held(&ax_local->spi_lock);

        isr = AX_READ(&ax_local->ax_spi, P0_ISR);
        AX_WRITE(&ax_local->ax_spi, isr, P0_ISR);

        netif_dbg(ax_local, intr, ndev, "  ISR 0x%04x\n", isr);

        if (isr & ISR_TXERR) {
                netif_dbg(ax_local, intr, ndev, "  TXERR interrupt\n");
                AX_WRITE(&ax_local->ax_spi, TXNR_TXB_REINIT, P0_TSNR);
                ax_local->seq_num = 0x1f;
        }

        if (isr & ISR_TXPAGES) {
                netif_dbg(ax_local, intr, ndev, "  TXPAGES interrupt\n");
                set_bit(EVENT_TX, &ax_local->flags);
        }

        if (isr & ISR_LINK) {
                netif_dbg(ax_local, intr, ndev, "  Link change interrupt\n");
                phy_mac_interrupt(ax_local->ndev->phydev);
        }

        if (isr & ISR_RXPKT) {
                netif_dbg(ax_local, intr, ndev, "  RX interrupt\n");
                todo = ax88796c_receive(ax_local->ndev);
        }

        return todo;
}

static irqreturn_t ax88796c_interrupt(int irq, void *dev_instance)
{
        struct ax88796c_device *ax_local;
        struct net_device *ndev;

        ndev = dev_instance;
        if (!ndev) {
                pr_err("irq %d for unknown device.\n", irq);
                return IRQ_RETVAL(0);
        }
        ax_local = to_ax88796c_device(ndev);

        disable_irq_nosync(irq);

        netif_dbg(ax_local, intr, ndev, "Interrupt occurred\n");

        set_bit(EVENT_INTR, &ax_local->flags);
        schedule_work(&ax_local->ax_work);

        return IRQ_HANDLED;
}

static void ax88796c_work(struct work_struct *work)
{
        struct ax88796c_device *ax_local =
                        container_of(work, struct ax88796c_device, ax_work);

        mutex_lock(&ax_local->spi_lock);

        if (test_bit(EVENT_SET_MULTI, &ax_local->flags)) {
                ax88796c_set_hw_multicast(ax_local->ndev);
                clear_bit(EVENT_SET_MULTI, &ax_local->flags);
        }

        if (test_bit(EVENT_INTR, &ax_local->flags)) {
                AX_WRITE(&ax_local->ax_spi, IMR_MASKALL, P0_IMR);

                while (ax88796c_process_isr(ax_local))
                        /* nothing */;

                clear_bit(EVENT_INTR, &ax_local->flags);

                AX_WRITE(&ax_local->ax_spi, IMR_DEFAULT, P0_IMR);

                enable_irq(ax_local->ndev->irq);
        }

        if (test_bit(EVENT_TX, &ax_local->flags)) {
                while (skb_queue_len(&ax_local->tx_wait_q)) {
                        if (!ax88796c_hard_xmit(ax_local))
                                break;
                }

                clear_bit(EVENT_TX, &ax_local->flags);

                if (netif_queue_stopped(ax_local->ndev) &&
                    (skb_queue_len(&ax_local->tx_wait_q) < TX_QUEUE_LOW_WATER))
                        netif_wake_queue(ax_local->ndev);
        }

        mutex_unlock(&ax_local->spi_lock);
}

static void ax88796c_get_stats64(struct net_device *ndev,
                                 struct rtnl_link_stats64 *stats)
{
        struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
        u32 rx_frame_errors = 0, rx_crc_errors = 0;
        u32 rx_dropped = 0, tx_dropped = 0;
        unsigned int start;
        int cpu;

        for_each_possible_cpu(cpu) {
                struct ax88796c_pcpu_stats *s;
                u64 rx_packets, rx_bytes;
                u64 tx_packets, tx_bytes;

                s = per_cpu_ptr(ax_local->stats, cpu);

                do {
                        start = u64_stats_fetch_begin(&s->syncp);
                        rx_packets = u64_stats_read(&s->rx_packets);
                        rx_bytes   = u64_stats_read(&s->rx_bytes);
                        tx_packets = u64_stats_read(&s->tx_packets);
                        tx_bytes   = u64_stats_read(&s->tx_bytes);
                } while (u64_stats_fetch_retry(&s->syncp, start));

                stats->rx_packets += rx_packets;
                stats->rx_bytes   += rx_bytes;
                stats->tx_packets += tx_packets;
                stats->tx_bytes   += tx_bytes;

                rx_dropped      += s->rx_dropped;
                tx_dropped      += s->tx_dropped;
                rx_frame_errors += s->rx_frame_errors;
                rx_crc_errors   += s->rx_crc_errors;
        }

        stats->rx_dropped = rx_dropped;
        stats->tx_dropped = tx_dropped;
        stats->rx_frame_errors = rx_frame_errors;
        stats->rx_crc_errors = rx_crc_errors;
}

static void ax88796c_set_mac(struct  ax88796c_device *ax_local)
{
        u16 maccr;

        maccr = (ax_local->link) ? MACCR_RXEN : 0;

        switch (ax_local->speed) {
        case SPEED_100:
                maccr |= MACCR_SPEED_100;
                break;
        case SPEED_10:
        case SPEED_UNKNOWN:
                break;
        default:
                return;
        }

        switch (ax_local->duplex) {
        case DUPLEX_FULL:
                maccr |= MACCR_SPEED_100;
                break;
        case DUPLEX_HALF:
        case DUPLEX_UNKNOWN:
                break;
        default:
                return;
        }

        if (ax_local->flowctrl & AX_FC_ANEG &&
            ax_local->phydev->autoneg) {
                maccr |= ax_local->pause ? MACCR_RXFC_ENABLE : 0;
                maccr |= !ax_local->pause != !ax_local->asym_pause ?
                        MACCR_TXFC_ENABLE : 0;
        } else {
                maccr |= (ax_local->flowctrl & AX_FC_RX) ? MACCR_RXFC_ENABLE : 0;
                maccr |= (ax_local->flowctrl & AX_FC_TX) ? MACCR_TXFC_ENABLE : 0;
        }

        mutex_lock(&ax_local->spi_lock);

        maccr |= AX_READ(&ax_local->ax_spi, P0_MACCR) &
                ~(MACCR_DUPLEX_FULL | MACCR_SPEED_100 |
                  MACCR_TXFC_ENABLE | MACCR_RXFC_ENABLE);
        AX_WRITE(&ax_local->ax_spi, maccr, P0_MACCR);

        mutex_unlock(&ax_local->spi_lock);
}

static void ax88796c_handle_link_change(struct net_device *ndev)
{
        struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
        struct phy_device *phydev = ndev->phydev;
        bool update = false;

        if (phydev->link && (ax_local->speed != phydev->speed ||
                             ax_local->duplex != phydev->duplex ||
                             ax_local->pause != phydev->pause ||
                             ax_local->asym_pause != phydev->asym_pause)) {
                ax_local->speed = phydev->speed;
                ax_local->duplex = phydev->duplex;
                ax_local->pause = phydev->pause;
                ax_local->asym_pause = phydev->asym_pause;
                update = true;
        }

        if (phydev->link != ax_local->link) {
                if (!phydev->link) {
                        ax_local->speed = SPEED_UNKNOWN;
                        ax_local->duplex = DUPLEX_UNKNOWN;
                }

                ax_local->link = phydev->link;
                update = true;
        }

        if (update)
                ax88796c_set_mac(ax_local);

        if (net_ratelimit())
                phy_print_status(ndev->phydev);
}

static void ax88796c_set_csums(struct ax88796c_device *ax_local)
{
        struct net_device *ndev = ax_local->ndev;

        lockdep_assert_held(&ax_local->spi_lock);

        if (ndev->features & NETIF_F_RXCSUM) {
                AX_WRITE(&ax_local->ax_spi, COERCR0_DEFAULT, P4_COERCR0);
                AX_WRITE(&ax_local->ax_spi, COERCR1_DEFAULT, P4_COERCR1);
        } else {
                AX_WRITE(&ax_local->ax_spi, 0, P4_COERCR0);
                AX_WRITE(&ax_local->ax_spi, 0, P4_COERCR1);
        }

        if (ndev->features & NETIF_F_HW_CSUM) {
                AX_WRITE(&ax_local->ax_spi, COETCR0_DEFAULT, P4_COETCR0);
                AX_WRITE(&ax_local->ax_spi, COETCR1_TXPPPE, P4_COETCR1);
        } else {
                AX_WRITE(&ax_local->ax_spi, 0, P4_COETCR0);
                AX_WRITE(&ax_local->ax_spi, 0, P4_COETCR1);
        }
}

static int
ax88796c_open(struct net_device *ndev)
{
        struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
        unsigned long irq_flag = 0;
        int fc = AX_FC_NONE;
        int ret;
        u16 t;

        ret = request_irq(ndev->irq, ax88796c_interrupt,
                          irq_flag, ndev->name, ndev);
        if (ret) {
                netdev_err(ndev, "unable to get IRQ %d (errno=%d).\n",
                           ndev->irq, ret);
                return ret;
        }

        mutex_lock(&ax_local->spi_lock);

        ret = ax88796c_soft_reset(ax_local);
        if (ret < 0) {
                free_irq(ndev->irq, ndev);
                mutex_unlock(&ax_local->spi_lock);
                return ret;
        }
        ax_local->seq_num = 0x1f;

        ax88796c_set_mac_addr(ndev);
        ax88796c_set_csums(ax_local);

        /* Disable stuffing packet */
        t = AX_READ(&ax_local->ax_spi, P1_RXBSPCR);
        t &= ~RXBSPCR_STUF_ENABLE;
        AX_WRITE(&ax_local->ax_spi, t, P1_RXBSPCR);

        /* Enable RX packet process */
        AX_WRITE(&ax_local->ax_spi, RPPER_RXEN, P1_RPPER);

        t = AX_READ(&ax_local->ax_spi, P0_FER);
        t |= FER_RXEN | FER_TXEN | FER_BSWAP | FER_IRQ_PULL;
        AX_WRITE(&ax_local->ax_spi, t, P0_FER);

        /* Setup LED mode */
        AX_WRITE(&ax_local->ax_spi,
                 (LCR_LED0_EN | LCR_LED0_DUPLEX | LCR_LED1_EN |
                 LCR_LED1_100MODE), P2_LCR0);
        AX_WRITE(&ax_local->ax_spi,
                 (AX_READ(&ax_local->ax_spi, P2_LCR1) & LCR_LED2_MASK) |
                 LCR_LED2_EN | LCR_LED2_LINK, P2_LCR1);

        /* Disable PHY auto-polling */
        AX_WRITE(&ax_local->ax_spi, PCR_PHYID(AX88796C_PHY_ID), P2_PCR);

        /* Enable MAC interrupts */
        AX_WRITE(&ax_local->ax_spi, IMR_DEFAULT, P0_IMR);

        mutex_unlock(&ax_local->spi_lock);

        /* Setup flow-control configuration */
        phy_support_asym_pause(ax_local->phydev);

        if (linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT,
                              ax_local->phydev->advertising) ||
            linkmode_test_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT,
                              ax_local->phydev->advertising))
                fc |= AX_FC_ANEG;

        fc |= linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT,
                                ax_local->phydev->advertising) ? AX_FC_RX : 0;
        fc |= (linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT,
                                 ax_local->phydev->advertising) !=
               linkmode_test_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT,
                                 ax_local->phydev->advertising)) ? AX_FC_TX : 0;
        ax_local->flowctrl = fc;

        phy_start(ax_local->ndev->phydev);

        netif_start_queue(ndev);

        spi_message_init(&ax_local->ax_spi.rx_msg);

        return 0;
}

static int
ax88796c_close(struct net_device *ndev)
{
        struct ax88796c_device *ax_local = to_ax88796c_device(ndev);

        phy_stop(ndev->phydev);

        /* We lock the mutex early not only to protect the device
         * against concurrent access, but also avoid waking up the
         * queue in ax88796c_work(). phy_stop() needs to be called
         * before because it locks the mutex to access SPI.
         */
        mutex_lock(&ax_local->spi_lock);

        netif_stop_queue(ndev);

        /* No more work can be scheduled now. Make any pending work,
         * including one already waiting for the mutex to be unlocked,
         * NOP.
         */
        netif_dbg(ax_local, ifdown, ndev, "clearing bits\n");
        clear_bit(EVENT_SET_MULTI, &ax_local->flags);
        clear_bit(EVENT_INTR, &ax_local->flags);
        clear_bit(EVENT_TX, &ax_local->flags);

        /* Disable MAC interrupts */
        AX_WRITE(&ax_local->ax_spi, IMR_MASKALL, P0_IMR);
        __skb_queue_purge(&ax_local->tx_wait_q);
        ax88796c_soft_reset(ax_local);

        mutex_unlock(&ax_local->spi_lock);

        cancel_work_sync(&ax_local->ax_work);

        free_irq(ndev->irq, ndev);

        return 0;
}

static int
ax88796c_set_features(struct net_device *ndev, netdev_features_t features)
{
        struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
        netdev_features_t changed = features ^ ndev->features;

        if (!(changed & (NETIF_F_RXCSUM | NETIF_F_HW_CSUM)))
                return 0;

        ndev->features = features;

        if (changed & (NETIF_F_RXCSUM | NETIF_F_HW_CSUM))
                ax88796c_set_csums(ax_local);

        return 0;
}

static const struct net_device_ops ax88796c_netdev_ops = {
        .ndo_open               = ax88796c_open,
        .ndo_stop               = ax88796c_close,
        .ndo_start_xmit         = ax88796c_start_xmit,
        .ndo_get_stats64        = ax88796c_get_stats64,
        .ndo_eth_ioctl          = ax88796c_ioctl,
        .ndo_set_mac_address    = eth_mac_addr,
        .ndo_set_features       = ax88796c_set_features,
};

static int ax88796c_hard_reset(struct ax88796c_device *ax_local)
{
        struct device *dev = (struct device *)&ax_local->spi->dev;
        struct gpio_desc *reset_gpio;

        /* reset info */
        reset_gpio = gpiod_get(dev, "reset", 0);
        if (IS_ERR(reset_gpio)) {
                dev_err(dev, "Could not get 'reset' GPIO: %ld", PTR_ERR(reset_gpio));
                return PTR_ERR(reset_gpio);
        }

        /* set reset */
        gpiod_direction_output(reset_gpio, 1);
        msleep(100);
        gpiod_direction_output(reset_gpio, 0);
        gpiod_put(reset_gpio);
        msleep(20);

        return 0;
}

static int ax88796c_probe(struct spi_device *spi)
{
        char phy_id[MII_BUS_ID_SIZE + 3];
        struct ax88796c_device *ax_local;
        struct net_device *ndev;
        u16 temp;
        int ret;

        ndev = devm_alloc_etherdev(&spi->dev, sizeof(*ax_local));
        if (!ndev)
                return -ENOMEM;

        SET_NETDEV_DEV(ndev, &spi->dev);

        ax_local = to_ax88796c_device(ndev);

        dev_set_drvdata(&spi->dev, ax_local);
        ax_local->spi = spi;
        ax_local->ax_spi.spi = spi;

        ax_local->stats =
                devm_netdev_alloc_pcpu_stats(&spi->dev,
                                             struct ax88796c_pcpu_stats);
        if (!ax_local->stats)
                return -ENOMEM;

        ax_local->ndev = ndev;
        ax_local->priv_flags |= comp ? AX_CAP_COMP : 0;
        ax_local->msg_enable = msg_enable;
        mutex_init(&ax_local->spi_lock);

        ax_local->mdiobus = devm_mdiobus_alloc(&spi->dev);
        if (!ax_local->mdiobus)
                return -ENOMEM;

        ax_local->mdiobus->priv = ax_local;
        ax_local->mdiobus->read = ax88796c_mdio_read;
        ax_local->mdiobus->write = ax88796c_mdio_write;
        ax_local->mdiobus->name = "ax88976c-mdiobus";
        ax_local->mdiobus->phy_mask = (u32)~BIT(AX88796C_PHY_ID);
        ax_local->mdiobus->parent = &spi->dev;

        snprintf(ax_local->mdiobus->id, MII_BUS_ID_SIZE,
                 "ax88796c-%s.%u", dev_name(&spi->dev), spi_get_chipselect(spi, 0));

        ret = devm_mdiobus_register(&spi->dev, ax_local->mdiobus);
        if (ret < 0) {
                dev_err(&spi->dev, "Could not register MDIO bus\n");
                return ret;
        }

        if (netif_msg_probe(ax_local)) {
                dev_info(&spi->dev, "AX88796C-SPI Configuration:\n");
                dev_info(&spi->dev, "    Compression : %s\n",
                         ax_local->priv_flags & AX_CAP_COMP ? "ON" : "OFF");
        }

        ndev->irq = spi->irq;
        ndev->netdev_ops = &ax88796c_netdev_ops;
        ndev->ethtool_ops = &ax88796c_ethtool_ops;
        ndev->hw_features |= NETIF_F_HW_CSUM | NETIF_F_RXCSUM;
        ndev->features |= NETIF_F_HW_CSUM | NETIF_F_RXCSUM;
        ndev->needed_headroom = TX_OVERHEAD;
        ndev->needed_tailroom = TX_EOP_SIZE;

        mutex_lock(&ax_local->spi_lock);

        /* ax88796c gpio reset */
        ax88796c_hard_reset(ax_local);

        /* Reset AX88796C */
        ret = ax88796c_soft_reset(ax_local);
        if (ret < 0) {
                ret = -ENODEV;
                mutex_unlock(&ax_local->spi_lock);
                goto err;
        }
        /* Check board revision */
        temp = AX_READ(&ax_local->ax_spi, P2_CRIR);
        if ((temp & 0xF) != 0x0) {
                dev_err(&spi->dev, "spi read failed: %d\n", temp);
                ret = -ENODEV;
                mutex_unlock(&ax_local->spi_lock);
                goto err;
        }

        /*Reload EEPROM*/
        ax88796c_reload_eeprom(ax_local);

        ax88796c_load_mac_addr(ndev);

        if (netif_msg_probe(ax_local))
                dev_info(&spi->dev,
                         "irq %d, MAC addr %02X:%02X:%02X:%02X:%02X:%02X\n",
                         ndev->irq,
                         ndev->dev_addr[0], ndev->dev_addr[1],
                         ndev->dev_addr[2], ndev->dev_addr[3],
                         ndev->dev_addr[4], ndev->dev_addr[5]);

        /* Disable power saving */
        AX_WRITE(&ax_local->ax_spi, (AX_READ(&ax_local->ax_spi, P0_PSCR)
                                     & PSCR_PS_MASK) | PSCR_PS_D0, P0_PSCR);

        mutex_unlock(&ax_local->spi_lock);

        INIT_WORK(&ax_local->ax_work, ax88796c_work);

        skb_queue_head_init(&ax_local->tx_wait_q);

        snprintf(phy_id, MII_BUS_ID_SIZE + 3, PHY_ID_FMT,
                 ax_local->mdiobus->id, AX88796C_PHY_ID);
        ax_local->phydev = phy_connect(ax_local->ndev, phy_id,
                                       ax88796c_handle_link_change,
                                       PHY_INTERFACE_MODE_MII);
        if (IS_ERR(ax_local->phydev)) {
                ret = PTR_ERR(ax_local->phydev);
                goto err;
        }
        ax_local->phydev->irq = PHY_POLL;

        ret = devm_register_netdev(&spi->dev, ndev);
        if (ret) {
                dev_err(&spi->dev, "failed to register a network device\n");
                goto err_phy_dis;
        }

        netif_info(ax_local, probe, ndev, "%s %s registered\n",
                   dev_driver_string(&spi->dev),
                   dev_name(&spi->dev));
        phy_attached_info(ax_local->phydev);

        return 0;

err_phy_dis:
        phy_disconnect(ax_local->phydev);
err:
        return ret;
}

static void ax88796c_remove(struct spi_device *spi)
{
        struct ax88796c_device *ax_local = dev_get_drvdata(&spi->dev);
        struct net_device *ndev = ax_local->ndev;

        phy_disconnect(ndev->phydev);

        netif_info(ax_local, probe, ndev, "removing network device %s %s\n",
                   dev_driver_string(&spi->dev),
                   dev_name(&spi->dev));
}

#ifdef CONFIG_OF
static const struct of_device_id ax88796c_dt_ids[] = {
        { .compatible = "asix,ax88796c" },
        {},
};
MODULE_DEVICE_TABLE(of, ax88796c_dt_ids);
#endif

static const struct spi_device_id asix_id[] = {
        { "ax88796c", 0 },
        { }
};
MODULE_DEVICE_TABLE(spi, asix_id);

static struct spi_driver ax88796c_spi_driver = {
        .driver = {
                .name = DRV_NAME,
                .of_match_table = of_match_ptr(ax88796c_dt_ids),
        },
        .probe = ax88796c_probe,
        .remove = ax88796c_remove,
        .id_table = asix_id,
};

static __init int ax88796c_spi_init(void)
{
        int ret;

        bitmap_zero(ax88796c_no_regs_mask, AX88796C_REGDUMP_LEN);
        ret = bitmap_parse(no_regs_list, 35,
                           ax88796c_no_regs_mask, AX88796C_REGDUMP_LEN);
        if (ret) {
                bitmap_fill(ax88796c_no_regs_mask, AX88796C_REGDUMP_LEN);
                pr_err("Invalid bitmap description, masking all registers\n");
        }

        return spi_register_driver(&ax88796c_spi_driver);
}

static __exit void ax88796c_spi_exit(void)
{
        spi_unregister_driver(&ax88796c_spi_driver);
}

module_init(ax88796c_spi_init);
module_exit(ax88796c_spi_exit);

MODULE_AUTHOR("Łukasz Stelmach <l.stelmach@samsung.com>");
MODULE_DESCRIPTION("ASIX AX88796C SPI Ethernet driver");
MODULE_LICENSE("GPL");