// SPDX-License-Identifier: GPL-2.0
/* Ethernet device driver for Cortina Systems Gemini SoC
 * Also known as the StorLink SL3512 and SL3516 (SL351x) or Lepus
 * Net Engine and Gigabit Ethernet MAC (GMAC)
 * This hardware contains a TCP Offload Engine (TOE) but currently the
 * driver does not make use of it.
 *
 * Authors:
 * Linus Walleij <linus.walleij@linaro.org>
 * Tobias Waldvogel <tobias.waldvogel@gmail.com> (OpenWRT)
 * Michał Mirosław <mirq-linux@rere.qmqm.pl>
 * Paulius Zaleckas <paulius.zaleckas@gmail.com>
 * Giuseppe De Robertis <Giuseppe.DeRobertis@ba.infn.it>
 * Gary Chen & Ch Hsu Storlink Semiconductor
 */
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/cache.h>
#include <linux/interrupt.h>
#include <linux/reset.h>
#include <linux/clk.h>
#include <linux/of.h>
#include <linux/of_mdio.h>
#include <linux/of_net.h>
#include <linux/of_platform.h>
#include <linux/etherdevice.h>
#include <linux/if_vlan.h>
#include <linux/skbuff.h>
#include <linux/phy.h>
#include <linux/crc32.h>
#include <linux/ethtool.h>
#include <linux/tcp.h>
#include <linux/u64_stats_sync.h>

#include <linux/in.h>
#include <linux/ip.h>
#include <linux/ipv6.h>

#include "gemini.h"

#define DRV_NAME                "gmac-gemini"
#define DRV_VERSION             "1.0"

#define DEFAULT_MSG_ENABLE (NETIF_MSG_DRV | NETIF_MSG_PROBE | NETIF_MSG_LINK)
static int debug = -1;
module_param(debug, int, 0);
MODULE_PARM_DESC(debug, "Debug level (0=none,...,16=all)");

#define HSIZE_8                 0x00
#define HSIZE_16                0x01
#define HSIZE_32                0x02

#define HBURST_SINGLE           0x00
#define HBURST_INCR             0x01
#define HBURST_INCR4            0x02
#define HBURST_INCR8            0x03

#define HPROT_DATA_CACHE        BIT(0)
#define HPROT_PRIVILIGED        BIT(1)
#define HPROT_BUFFERABLE        BIT(2)
#define HPROT_CACHABLE          BIT(3)

#define DEFAULT_RX_COALESCE_NSECS       0
#define DEFAULT_GMAC_RXQ_ORDER          9
#define DEFAULT_GMAC_TXQ_ORDER          8
#define DEFAULT_RX_BUF_ORDER            11
#define DEFAULT_NAPI_WEIGHT             64
#define TX_MAX_FRAGS                    16
#define TX_QUEUE_NUM                    1       /* max: 6 */
#define RX_MAX_ALLOC_ORDER              2

#define GMAC0_IRQ0_2 (GMAC0_TXDERR_INT_BIT | GMAC0_TXPERR_INT_BIT | \
                      GMAC0_RXDERR_INT_BIT | GMAC0_RXPERR_INT_BIT)
#define GMAC0_IRQ0_TXQ0_INTS (GMAC0_SWTQ00_EOF_INT_BIT | \
                              GMAC0_SWTQ00_FIN_INT_BIT)
#define GMAC0_IRQ4_8 (GMAC0_MIB_INT_BIT | GMAC0_RX_OVERRUN_INT_BIT)

#define GMAC_OFFLOAD_FEATURES (NETIF_F_SG | NETIF_F_IP_CSUM | \
                NETIF_F_IPV6_CSUM | NETIF_F_RXCSUM | \
                NETIF_F_TSO | NETIF_F_TSO_ECN | NETIF_F_TSO6)

/**
 * struct gmac_queue_page - page buffer per-page info
 */
struct gmac_queue_page {
        struct page *page;
        dma_addr_t mapping;
};

struct gmac_txq {
        struct gmac_txdesc *ring;
        struct sk_buff  **skb;
        unsigned int    cptr;
        unsigned int    noirq_packets;
};

struct gemini_ethernet;

struct gemini_ethernet_port {
        u8 id; /* 0 or 1 */

        struct gemini_ethernet *geth;
        struct net_device *netdev;
        struct device *dev;
        void __iomem *dma_base;
        void __iomem *gmac_base;
        struct clk *pclk;
        struct reset_control *reset;
        int irq;
        __le32 mac_addr[3];

        void __iomem            *rxq_rwptr;
        struct gmac_rxdesc      *rxq_ring;
        unsigned int            rxq_order;

        struct napi_struct      napi;
        struct hrtimer          rx_coalesce_timer;
        unsigned int            rx_coalesce_nsecs;
        unsigned int            freeq_refill;
        struct gmac_txq         txq[TX_QUEUE_NUM];
        unsigned int            txq_order;
        unsigned int            irq_every_tx_packets;

        dma_addr_t              rxq_dma_base;
        dma_addr_t              txq_dma_base;

        unsigned int            msg_enable;
        spinlock_t              config_lock; /* Locks config register */

        struct u64_stats_sync   tx_stats_syncp;
        struct u64_stats_sync   rx_stats_syncp;
        struct u64_stats_sync   ir_stats_syncp;

        struct rtnl_link_stats64 stats;
        u64                     hw_stats[RX_STATS_NUM];
        u64                     rx_stats[RX_STATUS_NUM];
        u64                     rx_csum_stats[RX_CHKSUM_NUM];
        u64                     rx_napi_exits;
        u64                     tx_frag_stats[TX_MAX_FRAGS];
        u64                     tx_frags_linearized;
        u64                     tx_hw_csummed;
};

struct gemini_ethernet {
        struct device *dev;
        void __iomem *base;
        struct gemini_ethernet_port *port0;
        struct gemini_ethernet_port *port1;
        bool initialized;

        spinlock_t      irq_lock; /* Locks IRQ-related registers */
        unsigned int    freeq_order;
        unsigned int    freeq_frag_order;
        struct gmac_rxdesc *freeq_ring;
        dma_addr_t      freeq_dma_base;
        struct gmac_queue_page  *freeq_pages;
        unsigned int    num_freeq_pages;
        spinlock_t      freeq_lock; /* Locks queue from reentrance */
};

#define GMAC_STATS_NUM  ( \
        RX_STATS_NUM + RX_STATUS_NUM + RX_CHKSUM_NUM + 1 + \
        TX_MAX_FRAGS + 2)

static const char gmac_stats_strings[GMAC_STATS_NUM][ETH_GSTRING_LEN] = {
        "GMAC_IN_DISCARDS",
        "GMAC_IN_ERRORS",
        "GMAC_IN_MCAST",
        "GMAC_IN_BCAST",
        "GMAC_IN_MAC1",
        "GMAC_IN_MAC2",
        "RX_STATUS_GOOD_FRAME",
        "RX_STATUS_TOO_LONG_GOOD_CRC",
        "RX_STATUS_RUNT_FRAME",
        "RX_STATUS_SFD_NOT_FOUND",
        "RX_STATUS_CRC_ERROR",
        "RX_STATUS_TOO_LONG_BAD_CRC",
        "RX_STATUS_ALIGNMENT_ERROR",
        "RX_STATUS_TOO_LONG_BAD_ALIGN",
        "RX_STATUS_RX_ERR",
        "RX_STATUS_DA_FILTERED",
        "RX_STATUS_BUFFER_FULL",
        "RX_STATUS_11",
        "RX_STATUS_12",
        "RX_STATUS_13",
        "RX_STATUS_14",
        "RX_STATUS_15",
        "RX_CHKSUM_IP_UDP_TCP_OK",
        "RX_CHKSUM_IP_OK_ONLY",
        "RX_CHKSUM_NONE",
        "RX_CHKSUM_3",
        "RX_CHKSUM_IP_ERR_UNKNOWN",
        "RX_CHKSUM_IP_ERR",
        "RX_CHKSUM_TCP_UDP_ERR",
        "RX_CHKSUM_7",
        "RX_NAPI_EXITS",
        "TX_FRAGS[1]",
        "TX_FRAGS[2]",
        "TX_FRAGS[3]",
        "TX_FRAGS[4]",
        "TX_FRAGS[5]",
        "TX_FRAGS[6]",
        "TX_FRAGS[7]",
        "TX_FRAGS[8]",
        "TX_FRAGS[9]",
        "TX_FRAGS[10]",
        "TX_FRAGS[11]",
        "TX_FRAGS[12]",
        "TX_FRAGS[13]",
        "TX_FRAGS[14]",
        "TX_FRAGS[15]",
        "TX_FRAGS[16+]",
        "TX_FRAGS_LINEARIZED",
        "TX_HW_CSUMMED",
};

static void gmac_dump_dma_state(struct net_device *netdev);

static void gmac_update_config0_reg(struct net_device *netdev,
                                    u32 val, u32 vmask)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        unsigned long flags;
        u32 reg;

        spin_lock_irqsave(&port->config_lock, flags);

        reg = readl(port->gmac_base + GMAC_CONFIG0);
        reg = (reg & ~vmask) | val;
        writel(reg, port->gmac_base + GMAC_CONFIG0);

        spin_unlock_irqrestore(&port->config_lock, flags);
}

static void gmac_enable_tx_rx(struct net_device *netdev)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        unsigned long flags;
        u32 reg;

        spin_lock_irqsave(&port->config_lock, flags);

        reg = readl(port->gmac_base + GMAC_CONFIG0);
        reg &= ~CONFIG0_TX_RX_DISABLE;
        writel(reg, port->gmac_base + GMAC_CONFIG0);

        spin_unlock_irqrestore(&port->config_lock, flags);
}

static void gmac_disable_tx_rx(struct net_device *netdev)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        unsigned long flags;
        u32 val;

        spin_lock_irqsave(&port->config_lock, flags);

        val = readl(port->gmac_base + GMAC_CONFIG0);
        val |= CONFIG0_TX_RX_DISABLE;
        writel(val, port->gmac_base + GMAC_CONFIG0);

        spin_unlock_irqrestore(&port->config_lock, flags);

        mdelay(10);     /* let GMAC consume packet */
}

static void gmac_set_flow_control(struct net_device *netdev, bool tx, bool rx)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        unsigned long flags;
        u32 val;

        spin_lock_irqsave(&port->config_lock, flags);

        val = readl(port->gmac_base + GMAC_CONFIG0);
        val &= ~CONFIG0_FLOW_CTL;
        if (tx)
                val |= CONFIG0_FLOW_TX;
        if (rx)
                val |= CONFIG0_FLOW_RX;
        writel(val, port->gmac_base + GMAC_CONFIG0);

        spin_unlock_irqrestore(&port->config_lock, flags);
}

static void gmac_speed_set(struct net_device *netdev)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        struct phy_device *phydev = netdev->phydev;
        union gmac_status status, old_status;
        int pause_tx = 0;
        int pause_rx = 0;

        status.bits32 = readl(port->gmac_base + GMAC_STATUS);
        old_status.bits32 = status.bits32;
        status.bits.link = phydev->link;
        status.bits.duplex = phydev->duplex;

        switch (phydev->speed) {
        case 1000:
                status.bits.speed = GMAC_SPEED_1000;
                if (phydev->interface == PHY_INTERFACE_MODE_RGMII)
                        status.bits.mii_rmii = GMAC_PHY_RGMII_1000;
                netdev_dbg(netdev, "connect %s to RGMII @ 1Gbit\n",
                           phydev_name(phydev));
                break;
        case 100:
                status.bits.speed = GMAC_SPEED_100;
                if (phydev->interface == PHY_INTERFACE_MODE_RGMII)
                        status.bits.mii_rmii = GMAC_PHY_RGMII_100_10;
                netdev_dbg(netdev, "connect %s to RGMII @ 100 Mbit\n",
                           phydev_name(phydev));
                break;
        case 10:
                status.bits.speed = GMAC_SPEED_10;
                if (phydev->interface == PHY_INTERFACE_MODE_RGMII)
                        status.bits.mii_rmii = GMAC_PHY_RGMII_100_10;
                netdev_dbg(netdev, "connect %s to RGMII @ 10 Mbit\n",
                           phydev_name(phydev));
                break;
        default:
                netdev_warn(netdev, "Unsupported PHY speed (%d) on %s\n",
                            phydev->speed, phydev_name(phydev));
        }

        if (phydev->duplex == DUPLEX_FULL) {
                u16 lcladv = phy_read(phydev, MII_ADVERTISE);
                u16 rmtadv = phy_read(phydev, MII_LPA);
                u8 cap = mii_resolve_flowctrl_fdx(lcladv, rmtadv);

                if (cap & FLOW_CTRL_RX)
                        pause_rx = 1;
                if (cap & FLOW_CTRL_TX)
                        pause_tx = 1;
        }

        gmac_set_flow_control(netdev, pause_tx, pause_rx);

        if (old_status.bits32 == status.bits32)
                return;

        if (netif_msg_link(port)) {
                phy_print_status(phydev);
                netdev_info(netdev, "link flow control: %s\n",
                            phydev->pause
                            ? (phydev->asym_pause ? "tx" : "both")
                            : (phydev->asym_pause ? "rx" : "none")
                );
        }

        gmac_disable_tx_rx(netdev);
        writel(status.bits32, port->gmac_base + GMAC_STATUS);
        gmac_enable_tx_rx(netdev);
}

static int gmac_setup_phy(struct net_device *netdev)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        union gmac_status status = { .bits32 = 0 };
        struct device *dev = port->dev;
        struct phy_device *phy;

        phy = of_phy_get_and_connect(netdev,
                                     dev->of_node,
                                     gmac_speed_set);
        if (!phy)
                return -ENODEV;
        netdev->phydev = phy;

        phy->supported &= PHY_GBIT_FEATURES;
        phy->supported |= SUPPORTED_Asym_Pause | SUPPORTED_Pause;
        phy->advertising = phy->supported;

        /* set PHY interface type */
        switch (phy->interface) {
        case PHY_INTERFACE_MODE_MII:
                netdev_dbg(netdev,
                           "MII: set GMAC0 to GMII mode, GMAC1 disabled\n");
                status.bits.mii_rmii = GMAC_PHY_MII;
                break;
        case PHY_INTERFACE_MODE_GMII:
                netdev_dbg(netdev,
                           "GMII: set GMAC0 to GMII mode, GMAC1 disabled\n");
                status.bits.mii_rmii = GMAC_PHY_GMII;
                break;
        case PHY_INTERFACE_MODE_RGMII:
                netdev_dbg(netdev,
                           "RGMII: set GMAC0 and GMAC1 to MII/RGMII mode\n");
                status.bits.mii_rmii = GMAC_PHY_RGMII_100_10;
                break;
        default:
                netdev_err(netdev, "Unsupported MII interface\n");
                phy_disconnect(phy);
                netdev->phydev = NULL;
                return -EINVAL;
        }
        writel(status.bits32, port->gmac_base + GMAC_STATUS);

        if (netif_msg_link(port))
                phy_attached_info(phy);

        return 0;
}

/* The maximum frame length is not logically enumerated in the
 * hardware, so we do a table lookup to find the applicable max
 * frame length.
 */
struct gmac_max_framelen {
        unsigned int max_l3_len;
        u8 val;
};

static const struct gmac_max_framelen gmac_maxlens[] = {
        {
                .max_l3_len = 1518,
                .val = CONFIG0_MAXLEN_1518,
        },
        {
                .max_l3_len = 1522,
                .val = CONFIG0_MAXLEN_1522,
        },
        {
                .max_l3_len = 1536,
                .val = CONFIG0_MAXLEN_1536,
        },
        {
                .max_l3_len = 1542,
                .val = CONFIG0_MAXLEN_1542,
        },
        {
                .max_l3_len = 9212,
                .val = CONFIG0_MAXLEN_9k,
        },
        {
                .max_l3_len = 10236,
                .val = CONFIG0_MAXLEN_10k,
        },
};

static int gmac_pick_rx_max_len(unsigned int max_l3_len)
{
        const struct gmac_max_framelen *maxlen;
        int maxtot;
        int i;

        maxtot = max_l3_len + ETH_HLEN + VLAN_HLEN;

        for (i = 0; i < ARRAY_SIZE(gmac_maxlens); i++) {
                maxlen = &gmac_maxlens[i];
                if (maxtot <= maxlen->max_l3_len)
                        return maxlen->val;
        }

        return -1;
}

static int gmac_init(struct net_device *netdev)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        union gmac_config0 config0 = { .bits = {
                .dis_tx = 1,
                .dis_rx = 1,
                .ipv4_rx_chksum = 1,
                .ipv6_rx_chksum = 1,
                .rx_err_detect = 1,
                .rgmm_edge = 1,
                .port0_chk_hwq = 1,
                .port1_chk_hwq = 1,
                .port0_chk_toeq = 1,
                .port1_chk_toeq = 1,
                .port0_chk_classq = 1,
                .port1_chk_classq = 1,
        } };
        union gmac_ahb_weight ahb_weight = { .bits = {
                .rx_weight = 1,
                .tx_weight = 1,
                .hash_weight = 1,
                .pre_req = 0x1f,
                .tq_dv_threshold = 0,
        } };
        union gmac_tx_wcr0 hw_weigh = { .bits = {
                .hw_tq3 = 1,
                .hw_tq2 = 1,
                .hw_tq1 = 1,
                .hw_tq0 = 1,
        } };
        union gmac_tx_wcr1 sw_weigh = { .bits = {
                .sw_tq5 = 1,
                .sw_tq4 = 1,
                .sw_tq3 = 1,
                .sw_tq2 = 1,
                .sw_tq1 = 1,
                .sw_tq0 = 1,
        } };
        union gmac_config1 config1 = { .bits = {
                .set_threshold = 16,
                .rel_threshold = 24,
        } };
        union gmac_config2 config2 = { .bits = {
                .set_threshold = 16,
                .rel_threshold = 32,
        } };
        union gmac_config3 config3 = { .bits = {
                .set_threshold = 0,
                .rel_threshold = 0,
        } };
        union gmac_config0 tmp;
        u32 val;

        config0.bits.max_len = gmac_pick_rx_max_len(netdev->mtu);
        tmp.bits32 = readl(port->gmac_base + GMAC_CONFIG0);
        config0.bits.reserved = tmp.bits.reserved;
        writel(config0.bits32, port->gmac_base + GMAC_CONFIG0);
        writel(config1.bits32, port->gmac_base + GMAC_CONFIG1);
        writel(config2.bits32, port->gmac_base + GMAC_CONFIG2);
        writel(config3.bits32, port->gmac_base + GMAC_CONFIG3);

        val = readl(port->dma_base + GMAC_AHB_WEIGHT_REG);
        writel(ahb_weight.bits32, port->dma_base + GMAC_AHB_WEIGHT_REG);

        writel(hw_weigh.bits32,
               port->dma_base + GMAC_TX_WEIGHTING_CTRL_0_REG);
        writel(sw_weigh.bits32,
               port->dma_base + GMAC_TX_WEIGHTING_CTRL_1_REG);

        port->rxq_order = DEFAULT_GMAC_RXQ_ORDER;
        port->txq_order = DEFAULT_GMAC_TXQ_ORDER;
        port->rx_coalesce_nsecs = DEFAULT_RX_COALESCE_NSECS;

        /* Mark every quarter of the queue a packet for interrupt
         * in order to be able to wake up the queue if it was stopped
         */
        port->irq_every_tx_packets = 1 << (port->txq_order - 2);

        return 0;
}

static void gmac_uninit(struct net_device *netdev)
{
        if (netdev->phydev)
                phy_disconnect(netdev->phydev);
}

static int gmac_setup_txqs(struct net_device *netdev)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        unsigned int n_txq = netdev->num_tx_queues;
        struct gemini_ethernet *geth = port->geth;
        size_t entries = 1 << port->txq_order;
        struct gmac_txq *txq = port->txq;
        struct gmac_txdesc *desc_ring;
        size_t len = n_txq * entries;
        struct sk_buff **skb_tab;
        void __iomem *rwptr_reg;
        unsigned int r;
        int i;

        rwptr_reg = port->dma_base + GMAC_SW_TX_QUEUE0_PTR_REG;

        skb_tab = kcalloc(len, sizeof(*skb_tab), GFP_KERNEL);
        if (!skb_tab)
                return -ENOMEM;

        desc_ring = dma_alloc_coherent(geth->dev, len * sizeof(*desc_ring),
                                       &port->txq_dma_base, GFP_KERNEL);

        if (!desc_ring) {
                kfree(skb_tab);
                return -ENOMEM;
        }

        if (port->txq_dma_base & ~DMA_Q_BASE_MASK) {
                dev_warn(geth->dev, "TX queue base is not aligned\n");
                kfree(skb_tab);
                return -ENOMEM;
        }

        writel(port->txq_dma_base | port->txq_order,
               port->dma_base + GMAC_SW_TX_QUEUE_BASE_REG);

        for (i = 0; i < n_txq; i++) {
                txq->ring = desc_ring;
                txq->skb = skb_tab;
                txq->noirq_packets = 0;

                r = readw(rwptr_reg);
                rwptr_reg += 2;
                writew(r, rwptr_reg);
                rwptr_reg += 2;
                txq->cptr = r;

                txq++;
                desc_ring += entries;
                skb_tab += entries;
        }

        return 0;
}

static void gmac_clean_txq(struct net_device *netdev, struct gmac_txq *txq,
                           unsigned int r)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        unsigned int m = (1 << port->txq_order) - 1;
        struct gemini_ethernet *geth = port->geth;
        unsigned int c = txq->cptr;
        union gmac_txdesc_0 word0;
        union gmac_txdesc_1 word1;
        unsigned int hwchksum = 0;
        unsigned long bytes = 0;
        struct gmac_txdesc *txd;
        unsigned short nfrags;
        unsigned int errs = 0;
        unsigned int pkts = 0;
        unsigned int word3;
        dma_addr_t mapping;

        if (c == r)
                return;

        while (c != r) {
                txd = txq->ring + c;
                word0 = txd->word0;
                word1 = txd->word1;
                mapping = txd->word2.buf_adr;
                word3 = txd->word3.bits32;

                dma_unmap_single(geth->dev, mapping,
                                 word0.bits.buffer_size, DMA_TO_DEVICE);

                if (word3 & EOF_BIT)
                        dev_kfree_skb(txq->skb[c]);

                c++;
                c &= m;

                if (!(word3 & SOF_BIT))
                        continue;

                if (!word0.bits.status_tx_ok) {
                        errs++;
                        continue;
                }

                pkts++;
                bytes += txd->word1.bits.byte_count;

                if (word1.bits32 & TSS_CHECKUM_ENABLE)
                        hwchksum++;

                nfrags = word0.bits.desc_count - 1;
                if (nfrags) {
                        if (nfrags >= TX_MAX_FRAGS)
                                nfrags = TX_MAX_FRAGS - 1;

                        u64_stats_update_begin(&port->tx_stats_syncp);
                        port->tx_frag_stats[nfrags]++;
                        u64_stats_update_end(&port->ir_stats_syncp);
                }
        }

        u64_stats_update_begin(&port->ir_stats_syncp);
        port->stats.tx_errors += errs;
        port->stats.tx_packets += pkts;
        port->stats.tx_bytes += bytes;
        port->tx_hw_csummed += hwchksum;
        u64_stats_update_end(&port->ir_stats_syncp);

        txq->cptr = c;
}

static void gmac_cleanup_txqs(struct net_device *netdev)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        unsigned int n_txq = netdev->num_tx_queues;
        struct gemini_ethernet *geth = port->geth;
        void __iomem *rwptr_reg;
        unsigned int r, i;

        rwptr_reg = port->dma_base + GMAC_SW_TX_QUEUE0_PTR_REG;

        for (i = 0; i < n_txq; i++) {
                r = readw(rwptr_reg);
                rwptr_reg += 2;
                writew(r, rwptr_reg);
                rwptr_reg += 2;

                gmac_clean_txq(netdev, port->txq + i, r);
        }
        writel(0, port->dma_base + GMAC_SW_TX_QUEUE_BASE_REG);

        kfree(port->txq->skb);
        dma_free_coherent(geth->dev,
                          n_txq * sizeof(*port->txq->ring) << port->txq_order,
                          port->txq->ring, port->txq_dma_base);
}

static int gmac_setup_rxq(struct net_device *netdev)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        struct gemini_ethernet *geth = port->geth;
        struct nontoe_qhdr __iomem *qhdr;

        qhdr = geth->base + TOE_DEFAULT_Q_HDR_BASE(netdev->dev_id);
        port->rxq_rwptr = &qhdr->word1;

        /* Remap a slew of memory to use for the RX queue */
        port->rxq_ring = dma_alloc_coherent(geth->dev,
                                sizeof(*port->rxq_ring) << port->rxq_order,
                                &port->rxq_dma_base, GFP_KERNEL);
        if (!port->rxq_ring)
                return -ENOMEM;
        if (port->rxq_dma_base & ~NONTOE_QHDR0_BASE_MASK) {
                dev_warn(geth->dev, "RX queue base is not aligned\n");
                return -ENOMEM;
        }

        writel(port->rxq_dma_base | port->rxq_order, &qhdr->word0);
        writel(0, port->rxq_rwptr);
        return 0;
}

static struct gmac_queue_page *
gmac_get_queue_page(struct gemini_ethernet *geth,
                    struct gemini_ethernet_port *port,
                    dma_addr_t addr)
{
        struct gmac_queue_page *gpage;
        dma_addr_t mapping;
        int i;

        /* Only look for even pages */
        mapping = addr & PAGE_MASK;

        if (!geth->freeq_pages) {
                dev_err(geth->dev, "try to get page with no page list\n");
                return NULL;
        }

        /* Look up a ring buffer page from virtual mapping */
        for (i = 0; i < geth->num_freeq_pages; i++) {
                gpage = &geth->freeq_pages[i];
                if (gpage->mapping == mapping)
                        return gpage;
        }

        return NULL;
}

static void gmac_cleanup_rxq(struct net_device *netdev)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        struct gemini_ethernet *geth = port->geth;
        struct gmac_rxdesc *rxd = port->rxq_ring;
        static struct gmac_queue_page *gpage;
        struct nontoe_qhdr __iomem *qhdr;
        void __iomem *dma_reg;
        void __iomem *ptr_reg;
        dma_addr_t mapping;
        union dma_rwptr rw;
        unsigned int r, w;

        qhdr = geth->base +
                TOE_DEFAULT_Q_HDR_BASE(netdev->dev_id);
        dma_reg = &qhdr->word0;
        ptr_reg = &qhdr->word1;

        rw.bits32 = readl(ptr_reg);
        r = rw.bits.rptr;
        w = rw.bits.wptr;
        writew(r, ptr_reg + 2);

        writel(0, dma_reg);

        /* Loop from read pointer to write pointer of the RX queue
         * and free up all pages by the queue.
         */
        while (r != w) {
                mapping = rxd[r].word2.buf_adr;
                r++;
                r &= ((1 << port->rxq_order) - 1);

                if (!mapping)
                        continue;

                /* Freeq pointers are one page off */
                gpage = gmac_get_queue_page(geth, port, mapping + PAGE_SIZE);
                if (!gpage) {
                        dev_err(geth->dev, "could not find page\n");
                        continue;
                }
                /* Release the RX queue reference to the page */
                put_page(gpage->page);
        }

        dma_free_coherent(geth->dev, sizeof(*port->rxq_ring) << port->rxq_order,
                          port->rxq_ring, port->rxq_dma_base);
}

static struct page *geth_freeq_alloc_map_page(struct gemini_ethernet *geth,
                                              int pn)
{
        struct gmac_rxdesc *freeq_entry;
        struct gmac_queue_page *gpage;
        unsigned int fpp_order;
        unsigned int frag_len;
        dma_addr_t mapping;
        struct page *page;
        int i;

        /* First allocate and DMA map a single page */
        page = alloc_page(GFP_ATOMIC);
        if (!page)
                return NULL;

        mapping = dma_map_single(geth->dev, page_address(page),
                                 PAGE_SIZE, DMA_FROM_DEVICE);
        if (dma_mapping_error(geth->dev, mapping)) {
                put_page(page);
                return NULL;
        }

        /* The assign the page mapping (physical address) to the buffer address
         * in the hardware queue. PAGE_SHIFT on ARM is 12 (1 page is 4096 bytes,
         * 4k), and the default RX frag order is 11 (fragments are up 20 2048
         * bytes, 2k) so fpp_order (fragments per page order) is default 1. Thus
         * each page normally needs two entries in the queue.
         */
        frag_len = 1 << geth->freeq_frag_order; /* Usually 2048 */
        fpp_order = PAGE_SHIFT - geth->freeq_frag_order;
        freeq_entry = geth->freeq_ring + (pn << fpp_order);
        dev_dbg(geth->dev, "allocate page %d fragment length %d fragments per page %d, freeq entry %p\n",
                 pn, frag_len, (1 << fpp_order), freeq_entry);
        for (i = (1 << fpp_order); i > 0; i--) {
                freeq_entry->word2.buf_adr = mapping;
                freeq_entry++;
                mapping += frag_len;
        }

        /* If the freeq entry already has a page mapped, then unmap it. */
        gpage = &geth->freeq_pages[pn];
        if (gpage->page) {
                mapping = geth->freeq_ring[pn << fpp_order].word2.buf_adr;
                dma_unmap_single(geth->dev, mapping, frag_len, DMA_FROM_DEVICE);
                /* This should be the last reference to the page so it gets
                 * released
                 */
                put_page(gpage->page);
        }

        /* Then put our new mapping into the page table */
        dev_dbg(geth->dev, "page %d, DMA addr: %08x, page %p\n",
                pn, (unsigned int)mapping, page);
        gpage->mapping = mapping;
        gpage->page = page;

        return page;
}

/**
 * geth_fill_freeq() - Fill the freeq with empty fragments to use
 * @geth: the ethernet adapter
 * @refill: whether to reset the queue by filling in all freeq entries or
 * just refill it, usually the interrupt to refill the queue happens when
 * the queue is half empty.
 */
static unsigned int geth_fill_freeq(struct gemini_ethernet *geth, bool refill)
{
        unsigned int fpp_order = PAGE_SHIFT - geth->freeq_frag_order;
        unsigned int count = 0;
        unsigned int pn, epn;
        unsigned long flags;
        union dma_rwptr rw;
        unsigned int m_pn;

        /* Mask for page */
        m_pn = (1 << (geth->freeq_order - fpp_order)) - 1;

        spin_lock_irqsave(&geth->freeq_lock, flags);

        rw.bits32 = readl(geth->base + GLOBAL_SWFQ_RWPTR_REG);
        pn = (refill ? rw.bits.wptr : rw.bits.rptr) >> fpp_order;
        epn = (rw.bits.rptr >> fpp_order) - 1;
        epn &= m_pn;

        /* Loop over the freeq ring buffer entries */
        while (pn != epn) {
                struct gmac_queue_page *gpage;
                struct page *page;

                gpage = &geth->freeq_pages[pn];
                page = gpage->page;

                dev_dbg(geth->dev, "fill entry %d page ref count %d add %d refs\n",
                        pn, page_ref_count(page), 1 << fpp_order);

                if (page_ref_count(page) > 1) {
                        unsigned int fl = (pn - epn) & m_pn;

                        if (fl > 64 >> fpp_order)
                                break;

                        page = geth_freeq_alloc_map_page(geth, pn);
                        if (!page)
                                break;
                }

                /* Add one reference per fragment in the page */
                page_ref_add(page, 1 << fpp_order);
                count += 1 << fpp_order;
                pn++;
                pn &= m_pn;
        }

        writew(pn << fpp_order, geth->base + GLOBAL_SWFQ_RWPTR_REG + 2);

        spin_unlock_irqrestore(&geth->freeq_lock, flags);

        return count;
}

static int geth_setup_freeq(struct gemini_ethernet *geth)
{
        unsigned int fpp_order = PAGE_SHIFT - geth->freeq_frag_order;
        unsigned int frag_len = 1 << geth->freeq_frag_order;
        unsigned int len = 1 << geth->freeq_order;
        unsigned int pages = len >> fpp_order;
        union queue_threshold qt;
        union dma_skb_size skbsz;
        unsigned int filled;
        unsigned int pn;

        geth->freeq_ring = dma_alloc_coherent(geth->dev,
                sizeof(*geth->freeq_ring) << geth->freeq_order,
                &geth->freeq_dma_base, GFP_KERNEL);
        if (!geth->freeq_ring)
                return -ENOMEM;
        if (geth->freeq_dma_base & ~DMA_Q_BASE_MASK) {
                dev_warn(geth->dev, "queue ring base is not aligned\n");
                goto err_freeq;
        }

        /* Allocate a mapping to page look-up index */
        geth->freeq_pages = kcalloc(pages, sizeof(*geth->freeq_pages),
                                    GFP_KERNEL);
        if (!geth->freeq_pages)
                goto err_freeq;
        geth->num_freeq_pages = pages;

        dev_info(geth->dev, "allocate %d pages for queue\n", pages);
        for (pn = 0; pn < pages; pn++)
                if (!geth_freeq_alloc_map_page(geth, pn))
                        goto err_freeq_alloc;

        filled = geth_fill_freeq(geth, false);
        if (!filled)
                goto err_freeq_alloc;

        qt.bits32 = readl(geth->base + GLOBAL_QUEUE_THRESHOLD_REG);
        qt.bits.swfq_empty = 32;
        writel(qt.bits32, geth->base + GLOBAL_QUEUE_THRESHOLD_REG);

        skbsz.bits.sw_skb_size = 1 << geth->freeq_frag_order;
        writel(skbsz.bits32, geth->base + GLOBAL_DMA_SKB_SIZE_REG);
        writel(geth->freeq_dma_base | geth->freeq_order,
               geth->base + GLOBAL_SW_FREEQ_BASE_SIZE_REG);

        return 0;

err_freeq_alloc:
        while (pn > 0) {
                struct gmac_queue_page *gpage;
                dma_addr_t mapping;

                --pn;
                mapping = geth->freeq_ring[pn << fpp_order].word2.buf_adr;
                dma_unmap_single(geth->dev, mapping, frag_len, DMA_FROM_DEVICE);
                gpage = &geth->freeq_pages[pn];
                put_page(gpage->page);
        }

        kfree(geth->freeq_pages);
err_freeq:
        dma_free_coherent(geth->dev,
                          sizeof(*geth->freeq_ring) << geth->freeq_order,
                          geth->freeq_ring, geth->freeq_dma_base);
        geth->freeq_ring = NULL;
        return -ENOMEM;
}

/**
 * geth_cleanup_freeq() - cleanup the DMA mappings and free the queue
 * @geth: the Gemini global ethernet state
 */

static void geth_cleanup_freeq(struct gemini_ethernet *geth)
{
        unsigned int fpp_order = PAGE_SHIFT - geth->freeq_frag_order;
        unsigned int frag_len = 1 << geth->freeq_frag_order;
        unsigned int len = 1 << geth->freeq_order;
        unsigned int pages = len >> fpp_order;
        unsigned int pn;

        writew(readw(geth->base + GLOBAL_SWFQ_RWPTR_REG),
               geth->base + GLOBAL_SWFQ_RWPTR_REG + 2);
        writel(0, geth->base + GLOBAL_SW_FREEQ_BASE_SIZE_REG);

        for (pn = 0; pn < pages; pn++) {
                struct gmac_queue_page *gpage;
                dma_addr_t mapping;

                mapping = geth->freeq_ring[pn << fpp_order].word2.buf_adr;
                dma_unmap_single(geth->dev, mapping, frag_len, DMA_FROM_DEVICE);

                gpage = &geth->freeq_pages[pn];
                while (page_ref_count(gpage->page) > 0)
                        put_page(gpage->page);
        }

        kfree(geth->freeq_pages);

        dma_free_coherent(geth->dev,
                          sizeof(*geth->freeq_ring) << geth->freeq_order,
                          geth->freeq_ring, geth->freeq_dma_base);
}

/**
 * geth_resize_freeq() - resize the software queue depth
 * @port: the port requesting the change
 *
 * This gets called at least once during probe() so the device queue gets
 * "resized" from the hardware defaults. Since both ports/net devices share
 * the same hardware queue, some synchronization between the ports is
 * needed.
 */
static int geth_resize_freeq(struct gemini_ethernet_port *port)
{
        struct gemini_ethernet *geth = port->geth;
        struct net_device *netdev = port->netdev;
        struct gemini_ethernet_port *other_port;
        struct net_device *other_netdev;
        unsigned int new_size = 0;
        unsigned int new_order;
        unsigned long flags;
        u32 en;
        int ret;

        if (netdev->dev_id == 0)
                other_netdev = geth->port1->netdev;
        else
                other_netdev = geth->port0->netdev;

        if (other_netdev && netif_running(other_netdev))
                return -EBUSY;

        new_size = 1 << (port->rxq_order + 1);
        netdev_dbg(netdev, "port %d size: %d order %d\n",
                   netdev->dev_id,
                   new_size,
                   port->rxq_order);
        if (other_netdev) {
                other_port = netdev_priv(other_netdev);
                new_size += 1 << (other_port->rxq_order + 1);
                netdev_dbg(other_netdev, "port %d size: %d order %d\n",
                           other_netdev->dev_id,
                           (1 << (other_port->rxq_order + 1)),
                           other_port->rxq_order);
        }

        new_order = min(15, ilog2(new_size - 1) + 1);
        dev_dbg(geth->dev, "set shared queue to size %d order %d\n",
                new_size, new_order);
        if (geth->freeq_order == new_order)
                return 0;

        spin_lock_irqsave(&geth->irq_lock, flags);

        /* Disable the software queue IRQs */
        en = readl(geth->base + GLOBAL_INTERRUPT_ENABLE_4_REG);
        en &= ~SWFQ_EMPTY_INT_BIT;
        writel(en, geth->base + GLOBAL_INTERRUPT_ENABLE_4_REG);
        spin_unlock_irqrestore(&geth->irq_lock, flags);

        /* Drop the old queue */
        if (geth->freeq_ring)
                geth_cleanup_freeq(geth);

        /* Allocate a new queue with the desired order */
        geth->freeq_order = new_order;
        ret = geth_setup_freeq(geth);

        /* Restart the interrupts - NOTE if this is the first resize
         * after probe(), this is where the interrupts get turned on
         * in the first place.
         */
        spin_lock_irqsave(&geth->irq_lock, flags);
        en |= SWFQ_EMPTY_INT_BIT;
        writel(en, geth->base + GLOBAL_INTERRUPT_ENABLE_4_REG);
        spin_unlock_irqrestore(&geth->irq_lock, flags);

        return ret;
}

static void gmac_tx_irq_enable(struct net_device *netdev,
                               unsigned int txq, int en)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        struct gemini_ethernet *geth = port->geth;
        u32 val, mask;

        netdev_dbg(netdev, "%s device %d\n", __func__, netdev->dev_id);

        mask = GMAC0_IRQ0_TXQ0_INTS << (6 * netdev->dev_id + txq);

        if (en)
                writel(mask, geth->base + GLOBAL_INTERRUPT_STATUS_0_REG);

        val = readl(geth->base + GLOBAL_INTERRUPT_ENABLE_0_REG);
        val = en ? val | mask : val & ~mask;
        writel(val, geth->base + GLOBAL_INTERRUPT_ENABLE_0_REG);
}

static void gmac_tx_irq(struct net_device *netdev, unsigned int txq_num)
{
        struct netdev_queue *ntxq = netdev_get_tx_queue(netdev, txq_num);

        gmac_tx_irq_enable(netdev, txq_num, 0);
        netif_tx_wake_queue(ntxq);
}

static int gmac_map_tx_bufs(struct net_device *netdev, struct sk_buff *skb,
                            struct gmac_txq *txq, unsigned short *desc)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        struct skb_shared_info *skb_si =  skb_shinfo(skb);
        unsigned short m = (1 << port->txq_order) - 1;
        short frag, last_frag = skb_si->nr_frags - 1;
        struct gemini_ethernet *geth = port->geth;
        unsigned int word1, word3, buflen;
        unsigned short w = *desc;
        struct gmac_txdesc *txd;
        skb_frag_t *skb_frag;
        dma_addr_t mapping;
        unsigned short mtu;
        void *buffer;

        mtu  = ETH_HLEN;
        mtu += netdev->mtu;
        if (skb->protocol == htons(ETH_P_8021Q))
                mtu += VLAN_HLEN;

        word1 = skb->len;
        word3 = SOF_BIT;

        if (word1 > mtu) {
                word1 |= TSS_MTU_ENABLE_BIT;
                word3 |= mtu;
        }

        if (skb->ip_summed != CHECKSUM_NONE) {
                int tcp = 0;

                if (skb->protocol == htons(ETH_P_IP)) {
                        word1 |= TSS_IP_CHKSUM_BIT;
                        tcp = ip_hdr(skb)->protocol == IPPROTO_TCP;
                } else { /* IPv6 */
                        word1 |= TSS_IPV6_ENABLE_BIT;
                        tcp = ipv6_hdr(skb)->nexthdr == IPPROTO_TCP;
                }

                word1 |= tcp ? TSS_TCP_CHKSUM_BIT : TSS_UDP_CHKSUM_BIT;
        }

        frag = -1;
        while (frag <= last_frag) {
                if (frag == -1) {
                        buffer = skb->data;
                        buflen = skb_headlen(skb);
                } else {
                        skb_frag = skb_si->frags + frag;
                        buffer = page_address(skb_frag_page(skb_frag)) +
                                 skb_frag->page_offset;
                        buflen = skb_frag->size;
                }

                if (frag == last_frag) {
                        word3 |= EOF_BIT;
                        txq->skb[w] = skb;
                }

                mapping = dma_map_single(geth->dev, buffer, buflen,
                                         DMA_TO_DEVICE);
                if (dma_mapping_error(geth->dev, mapping))
                        goto map_error;

                txd = txq->ring + w;
                txd->word0.bits32 = buflen;
                txd->word1.bits32 = word1;
                txd->word2.buf_adr = mapping;
                txd->word3.bits32 = word3;

                word3 &= MTU_SIZE_BIT_MASK;
                w++;
                w &= m;
                frag++;
        }

        *desc = w;
        return 0;

map_error:
        while (w != *desc) {
                w--;
                w &= m;

                dma_unmap_page(geth->dev, txq->ring[w].word2.buf_adr,
                               txq->ring[w].word0.bits.buffer_size,
                               DMA_TO_DEVICE);
        }
        return -ENOMEM;
}

static int gmac_start_xmit(struct sk_buff *skb, struct net_device *netdev)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        unsigned short m = (1 << port->txq_order) - 1;
        struct netdev_queue *ntxq;
        unsigned short r, w, d;
        void __iomem *ptr_reg;
        struct gmac_txq *txq;
        int txq_num, nfrags;
        union dma_rwptr rw;

        SKB_FRAG_ASSERT(skb);

        if (skb->len >= 0x10000)
                goto out_drop_free;

        txq_num = skb_get_queue_mapping(skb);
        ptr_reg = port->dma_base + GMAC_SW_TX_QUEUE_PTR_REG(txq_num);
        txq = &port->txq[txq_num];
        ntxq = netdev_get_tx_queue(netdev, txq_num);
        nfrags = skb_shinfo(skb)->nr_frags;

        rw.bits32 = readl(ptr_reg);
        r = rw.bits.rptr;
        w = rw.bits.wptr;

        d = txq->cptr - w - 1;
        d &= m;

        if (d < nfrags + 2) {
                gmac_clean_txq(netdev, txq, r);
                d = txq->cptr - w - 1;
                d &= m;

                if (d < nfrags + 2) {
                        netif_tx_stop_queue(ntxq);

                        d = txq->cptr + nfrags + 16;
                        d &= m;
                        txq->ring[d].word3.bits.eofie = 1;
                        gmac_tx_irq_enable(netdev, txq_num, 1);

                        u64_stats_update_begin(&port->tx_stats_syncp);
                        netdev->stats.tx_fifo_errors++;
                        u64_stats_update_end(&port->tx_stats_syncp);
                        return NETDEV_TX_BUSY;
                }
        }

        if (gmac_map_tx_bufs(netdev, skb, txq, &w)) {
                if (skb_linearize(skb))
                        goto out_drop;

                u64_stats_update_begin(&port->tx_stats_syncp);
                port->tx_frags_linearized++;
                u64_stats_update_end(&port->tx_stats_syncp);

                if (gmac_map_tx_bufs(netdev, skb, txq, &w))
                        goto out_drop_free;
        }

        writew(w, ptr_reg + 2);

        gmac_clean_txq(netdev, txq, r);
        return NETDEV_TX_OK;

out_drop_free:
        dev_kfree_skb(skb);
out_drop:
        u64_stats_update_begin(&port->tx_stats_syncp);
        port->stats.tx_dropped++;
        u64_stats_update_end(&port->tx_stats_syncp);
        return NETDEV_TX_OK;
}

static void gmac_tx_timeout(struct net_device *netdev)
{
        netdev_err(netdev, "Tx timeout\n");
        gmac_dump_dma_state(netdev);
}

static void gmac_enable_irq(struct net_device *netdev, int enable)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        struct gemini_ethernet *geth = port->geth;
        unsigned long flags;
        u32 val, mask;

        netdev_dbg(netdev, "%s device %d %s\n", __func__,
                   netdev->dev_id, enable ? "enable" : "disable");
        spin_lock_irqsave(&geth->irq_lock, flags);

        mask = GMAC0_IRQ0_2 << (netdev->dev_id * 2);
        val = readl(geth->base + GLOBAL_INTERRUPT_ENABLE_0_REG);
        val = enable ? (val | mask) : (val & ~mask);
        writel(val, geth->base + GLOBAL_INTERRUPT_ENABLE_0_REG);

        mask = DEFAULT_Q0_INT_BIT << netdev->dev_id;
        val = readl(geth->base + GLOBAL_INTERRUPT_ENABLE_1_REG);
        val = enable ? (val | mask) : (val & ~mask);
        writel(val, geth->base + GLOBAL_INTERRUPT_ENABLE_1_REG);

        mask = GMAC0_IRQ4_8 << (netdev->dev_id * 8);
        val = readl(geth->base + GLOBAL_INTERRUPT_ENABLE_4_REG);
        val = enable ? (val | mask) : (val & ~mask);
        writel(val, geth->base + GLOBAL_INTERRUPT_ENABLE_4_REG);

        spin_unlock_irqrestore(&geth->irq_lock, flags);
}

static void gmac_enable_rx_irq(struct net_device *netdev, int enable)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        struct gemini_ethernet *geth = port->geth;
        unsigned long flags;
        u32 val, mask;

        netdev_dbg(netdev, "%s device %d %s\n", __func__, netdev->dev_id,
                   enable ? "enable" : "disable");
        spin_lock_irqsave(&geth->irq_lock, flags);
        mask = DEFAULT_Q0_INT_BIT << netdev->dev_id;

        val = readl(geth->base + GLOBAL_INTERRUPT_ENABLE_1_REG);
        val = enable ? (val | mask) : (val & ~mask);
        writel(val, geth->base + GLOBAL_INTERRUPT_ENABLE_1_REG);

        spin_unlock_irqrestore(&geth->irq_lock, flags);
}

static struct sk_buff *gmac_skb_if_good_frame(struct gemini_ethernet_port *port,
                                              union gmac_rxdesc_0 word0,
                                              unsigned int frame_len)
{
        unsigned int rx_csum = word0.bits.chksum_status;
        unsigned int rx_status = word0.bits.status;
        struct sk_buff *skb = NULL;

        port->rx_stats[rx_status]++;
        port->rx_csum_stats[rx_csum]++;

        if (word0.bits.derr || word0.bits.perr ||
            rx_status || frame_len < ETH_ZLEN ||
            rx_csum >= RX_CHKSUM_IP_ERR_UNKNOWN) {
                port->stats.rx_errors++;

                if (frame_len < ETH_ZLEN || RX_ERROR_LENGTH(rx_status))
                        port->stats.rx_length_errors++;
                if (RX_ERROR_OVER(rx_status))
                        port->stats.rx_over_errors++;
                if (RX_ERROR_CRC(rx_status))
                        port->stats.rx_crc_errors++;
                if (RX_ERROR_FRAME(rx_status))
                        port->stats.rx_frame_errors++;
                return NULL;
        }

        skb = napi_get_frags(&port->napi);
        if (!skb)
                goto update_exit;

        if (rx_csum == RX_CHKSUM_IP_UDP_TCP_OK)
                skb->ip_summed = CHECKSUM_UNNECESSARY;

update_exit:
        port->stats.rx_bytes += frame_len;
        port->stats.rx_packets++;
        return skb;
}

static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        unsigned short m = (1 << port->rxq_order) - 1;
        struct gemini_ethernet *geth = port->geth;
        void __iomem *ptr_reg = port->rxq_rwptr;
        unsigned int frame_len, frag_len;
        struct gmac_rxdesc *rx = NULL;
        struct gmac_queue_page *gpage;
        static struct sk_buff *skb;
        union gmac_rxdesc_0 word0;
        union gmac_rxdesc_1 word1;
        union gmac_rxdesc_3 word3;
        struct page *page = NULL;
        unsigned int page_offs;
        unsigned short r, w;
        union dma_rwptr rw;
        dma_addr_t mapping;
        int frag_nr = 0;

        rw.bits32 = readl(ptr_reg);
        /* Reset interrupt as all packages until here are taken into account */
        writel(DEFAULT_Q0_INT_BIT << netdev->dev_id,
               geth->base + GLOBAL_INTERRUPT_STATUS_1_REG);
        r = rw.bits.rptr;
        w = rw.bits.wptr;

        while (budget && w != r) {
                rx = port->rxq_ring + r;
                word0 = rx->word0;
                word1 = rx->word1;
                mapping = rx->word2.buf_adr;
                word3 = rx->word3;

                r++;
                r &= m;

                frag_len = word0.bits.buffer_size;
                frame_len = word1.bits.byte_count;
                page_offs = mapping & ~PAGE_MASK;

                if (!mapping) {
                        netdev_err(netdev,
                                   "rxq[%u]: HW BUG: zero DMA desc\n", r);
                        goto err_drop;
                }

                /* Freeq pointers are one page off */
                gpage = gmac_get_queue_page(geth, port, mapping + PAGE_SIZE);
                if (!gpage) {
                        dev_err(geth->dev, "could not find mapping\n");
                        continue;
                }
                page = gpage->page;

                if (word3.bits32 & SOF_BIT) {
                        if (skb) {
                                napi_free_frags(&port->napi);
                                port->stats.rx_dropped++;
                        }

                        skb = gmac_skb_if_good_frame(port, word0, frame_len);
                        if (!skb)
                                goto err_drop;

                        page_offs += NET_IP_ALIGN;
                        frag_len -= NET_IP_ALIGN;
                        frag_nr = 0;

                } else if (!skb) {
                        put_page(page);
                        continue;
                }

                if (word3.bits32 & EOF_BIT)
                        frag_len = frame_len - skb->len;

                /* append page frag to skb */
                if (frag_nr == MAX_SKB_FRAGS)
                        goto err_drop;

                if (frag_len == 0)
                        netdev_err(netdev, "Received fragment with len = 0\n");

                skb_fill_page_desc(skb, frag_nr, page, page_offs, frag_len);
                skb->len += frag_len;
                skb->data_len += frag_len;
                skb->truesize += frag_len;
                frag_nr++;

                if (word3.bits32 & EOF_BIT) {
                        napi_gro_frags(&port->napi);
                        skb = NULL;
                        --budget;
                }
                continue;

err_drop:
                if (skb) {
                        napi_free_frags(&port->napi);
                        skb = NULL;
                }

                if (mapping)
                        put_page(page);

                port->stats.rx_dropped++;
        }

        writew(r, ptr_reg);
        return budget;
}

static int gmac_napi_poll(struct napi_struct *napi, int budget)
{
        struct gemini_ethernet_port *port = netdev_priv(napi->dev);
        struct gemini_ethernet *geth = port->geth;
        unsigned int freeq_threshold;
        unsigned int received;

        freeq_threshold = 1 << (geth->freeq_order - 1);
        u64_stats_update_begin(&port->rx_stats_syncp);

        received = gmac_rx(napi->dev, budget);
        if (received < budget) {
                napi_gro_flush(napi, false);
                napi_complete_done(napi, received);
                gmac_enable_rx_irq(napi->dev, 1);
                ++port->rx_napi_exits;
        }

        port->freeq_refill += (budget - received);
        if (port->freeq_refill > freeq_threshold) {
                port->freeq_refill -= freeq_threshold;
                geth_fill_freeq(geth, true);
        }

        u64_stats_update_end(&port->rx_stats_syncp);
        return received;
}

static void gmac_dump_dma_state(struct net_device *netdev)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        struct gemini_ethernet *geth = port->geth;
        void __iomem *ptr_reg;
        u32 reg[5];

        /* Interrupt status */
        reg[0] = readl(geth->base + GLOBAL_INTERRUPT_STATUS_0_REG);
        reg[1] = readl(geth->base + GLOBAL_INTERRUPT_STATUS_1_REG);
        reg[2] = readl(geth->base + GLOBAL_INTERRUPT_STATUS_2_REG);
        reg[3] = readl(geth->base + GLOBAL_INTERRUPT_STATUS_3_REG);
        reg[4] = readl(geth->base + GLOBAL_INTERRUPT_STATUS_4_REG);
        netdev_err(netdev, "IRQ status: 0x%08x 0x%08x 0x%08x 0x%08x 0x%08x\n",
                   reg[0], reg[1], reg[2], reg[3], reg[4]);

        /* Interrupt enable */
        reg[0] = readl(geth->base + GLOBAL_INTERRUPT_ENABLE_0_REG);
        reg[1] = readl(geth->base + GLOBAL_INTERRUPT_ENABLE_1_REG);
        reg[2] = readl(geth->base + GLOBAL_INTERRUPT_ENABLE_2_REG);
        reg[3] = readl(geth->base + GLOBAL_INTERRUPT_ENABLE_3_REG);
        reg[4] = readl(geth->base + GLOBAL_INTERRUPT_ENABLE_4_REG);
        netdev_err(netdev, "IRQ enable: 0x%08x 0x%08x 0x%08x 0x%08x 0x%08x\n",
                   reg[0], reg[1], reg[2], reg[3], reg[4]);

        /* RX DMA status */
        reg[0] = readl(port->dma_base + GMAC_DMA_RX_FIRST_DESC_REG);
        reg[1] = readl(port->dma_base + GMAC_DMA_RX_CURR_DESC_REG);
        reg[2] = GET_RPTR(port->rxq_rwptr);
        reg[3] = GET_WPTR(port->rxq_rwptr);
        netdev_err(netdev, "RX DMA regs: 0x%08x 0x%08x, ptr: %u %u\n",
                   reg[0], reg[1], reg[2], reg[3]);

        reg[0] = readl(port->dma_base + GMAC_DMA_RX_DESC_WORD0_REG);
        reg[1] = readl(port->dma_base + GMAC_DMA_RX_DESC_WORD1_REG);
        reg[2] = readl(port->dma_base + GMAC_DMA_RX_DESC_WORD2_REG);
        reg[3] = readl(port->dma_base + GMAC_DMA_RX_DESC_WORD3_REG);
        netdev_err(netdev, "RX DMA descriptor: 0x%08x 0x%08x 0x%08x 0x%08x\n",
                   reg[0], reg[1], reg[2], reg[3]);

        /* TX DMA status */
        ptr_reg = port->dma_base + GMAC_SW_TX_QUEUE0_PTR_REG;

        reg[0] = readl(port->dma_base + GMAC_DMA_TX_FIRST_DESC_REG);
        reg[1] = readl(port->dma_base + GMAC_DMA_TX_CURR_DESC_REG);
        reg[2] = GET_RPTR(ptr_reg);
        reg[3] = GET_WPTR(ptr_reg);
        netdev_err(netdev, "TX DMA regs: 0x%08x 0x%08x, ptr: %u %u\n",
                   reg[0], reg[1], reg[2], reg[3]);

        reg[0] = readl(port->dma_base + GMAC_DMA_TX_DESC_WORD0_REG);
        reg[1] = readl(port->dma_base + GMAC_DMA_TX_DESC_WORD1_REG);
        reg[2] = readl(port->dma_base + GMAC_DMA_TX_DESC_WORD2_REG);
        reg[3] = readl(port->dma_base + GMAC_DMA_TX_DESC_WORD3_REG);
        netdev_err(netdev, "TX DMA descriptor: 0x%08x 0x%08x 0x%08x 0x%08x\n",
                   reg[0], reg[1], reg[2], reg[3]);

        /* FREE queues status */
        ptr_reg = geth->base + GLOBAL_SWFQ_RWPTR_REG;

        reg[0] = GET_RPTR(ptr_reg);
        reg[1] = GET_WPTR(ptr_reg);

        ptr_reg = geth->base + GLOBAL_HWFQ_RWPTR_REG;

        reg[2] = GET_RPTR(ptr_reg);
        reg[3] = GET_WPTR(ptr_reg);
        netdev_err(netdev, "FQ SW ptr: %u %u, HW ptr: %u %u\n",
                   reg[0], reg[1], reg[2], reg[3]);
}

static void gmac_update_hw_stats(struct net_device *netdev)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        unsigned int rx_discards, rx_mcast, rx_bcast;
        struct gemini_ethernet *geth = port->geth;
        unsigned long flags;

        spin_lock_irqsave(&geth->irq_lock, flags);
        u64_stats_update_begin(&port->ir_stats_syncp);

        rx_discards = readl(port->gmac_base + GMAC_IN_DISCARDS);
        port->hw_stats[0] += rx_discards;
        port->hw_stats[1] += readl(port->gmac_base + GMAC_IN_ERRORS);
        rx_mcast = readl(port->gmac_base + GMAC_IN_MCAST);
        port->hw_stats[2] += rx_mcast;
        rx_bcast = readl(port->gmac_base + GMAC_IN_BCAST);
        port->hw_stats[3] += rx_bcast;
        port->hw_stats[4] += readl(port->gmac_base + GMAC_IN_MAC1);
        port->hw_stats[5] += readl(port->gmac_base + GMAC_IN_MAC2);

        port->stats.rx_missed_errors += rx_discards;
        port->stats.multicast += rx_mcast;
        port->stats.multicast += rx_bcast;

        writel(GMAC0_MIB_INT_BIT << (netdev->dev_id * 8),
               geth->base + GLOBAL_INTERRUPT_STATUS_4_REG);

        u64_stats_update_end(&port->ir_stats_syncp);
        spin_unlock_irqrestore(&geth->irq_lock, flags);
}

/**
 * gmac_get_intr_flags() - get interrupt status flags for a port from
 * @netdev: the net device for the port to get flags from
 * @i: the interrupt status register 0..4
 */
static u32 gmac_get_intr_flags(struct net_device *netdev, int i)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        struct gemini_ethernet *geth = port->geth;
        void __iomem *irqif_reg, *irqen_reg;
        unsigned int offs, val;

        /* Calculate the offset using the stride of the status registers */
        offs = i * (GLOBAL_INTERRUPT_STATUS_1_REG -
                    GLOBAL_INTERRUPT_STATUS_0_REG);

        irqif_reg = geth->base + GLOBAL_INTERRUPT_STATUS_0_REG + offs;
        irqen_reg = geth->base + GLOBAL_INTERRUPT_ENABLE_0_REG + offs;

        val = readl(irqif_reg) & readl(irqen_reg);
        return val;
}

static enum hrtimer_restart gmac_coalesce_delay_expired(struct hrtimer *timer)
{
        struct gemini_ethernet_port *port =
                container_of(timer, struct gemini_ethernet_port,
                             rx_coalesce_timer);

        napi_schedule(&port->napi);
        return HRTIMER_NORESTART;
}

static irqreturn_t gmac_irq(int irq, void *data)
{
        struct gemini_ethernet_port *port;
        struct net_device *netdev = data;
        struct gemini_ethernet *geth;
        u32 val, orr = 0;

        port = netdev_priv(netdev);
        geth = port->geth;

        val = gmac_get_intr_flags(netdev, 0);
        orr |= val;

        if (val & (GMAC0_IRQ0_2 << (netdev->dev_id * 2))) {
                /* Oh, crap */
                netdev_err(netdev, "hw failure/sw bug\n");
                gmac_dump_dma_state(netdev);

                /* don't know how to recover, just reduce losses */
                gmac_enable_irq(netdev, 0);
                return IRQ_HANDLED;
        }

        if (val & (GMAC0_IRQ0_TXQ0_INTS << (netdev->dev_id * 6)))
                gmac_tx_irq(netdev, 0);

        val = gmac_get_intr_flags(netdev, 1);
        orr |= val;

        if (val & (DEFAULT_Q0_INT_BIT << netdev->dev_id)) {
                gmac_enable_rx_irq(netdev, 0);

                if (!port->rx_coalesce_nsecs) {
                        napi_schedule(&port->napi);
                } else {
                        ktime_t ktime;

                        ktime = ktime_set(0, port->rx_coalesce_nsecs);
                        hrtimer_start(&port->rx_coalesce_timer, ktime,
                                      HRTIMER_MODE_REL);
                }
        }

        val = gmac_get_intr_flags(netdev, 4);
        orr |= val;

        if (val & (GMAC0_MIB_INT_BIT << (netdev->dev_id * 8)))
                gmac_update_hw_stats(netdev);

        if (val & (GMAC0_RX_OVERRUN_INT_BIT << (netdev->dev_id * 8))) {
                writel(GMAC0_RXDERR_INT_BIT << (netdev->dev_id * 8),
                       geth->base + GLOBAL_INTERRUPT_STATUS_4_REG);

                spin_lock(&geth->irq_lock);
                u64_stats_update_begin(&port->ir_stats_syncp);
                ++port->stats.rx_fifo_errors;
                u64_stats_update_end(&port->ir_stats_syncp);
                spin_unlock(&geth->irq_lock);
        }

        return orr ? IRQ_HANDLED : IRQ_NONE;
}

static void gmac_start_dma(struct gemini_ethernet_port *port)
{
        void __iomem *dma_ctrl_reg = port->dma_base + GMAC_DMA_CTRL_REG;
        union gmac_dma_ctrl dma_ctrl;

        dma_ctrl.bits32 = readl(dma_ctrl_reg);
        dma_ctrl.bits.rd_enable = 1;
        dma_ctrl.bits.td_enable = 1;
        dma_ctrl.bits.loopback = 0;
        dma_ctrl.bits.drop_small_ack = 0;
        dma_ctrl.bits.rd_insert_bytes = NET_IP_ALIGN;
        dma_ctrl.bits.rd_prot = HPROT_DATA_CACHE | HPROT_PRIVILIGED;
        dma_ctrl.bits.rd_burst_size = HBURST_INCR8;
        dma_ctrl.bits.rd_bus = HSIZE_8;
        dma_ctrl.bits.td_prot = HPROT_DATA_CACHE;
        dma_ctrl.bits.td_burst_size = HBURST_INCR8;
        dma_ctrl.bits.td_bus = HSIZE_8;

        writel(dma_ctrl.bits32, dma_ctrl_reg);
}

static void gmac_stop_dma(struct gemini_ethernet_port *port)
{
        void __iomem *dma_ctrl_reg = port->dma_base + GMAC_DMA_CTRL_REG;
        union gmac_dma_ctrl dma_ctrl;

        dma_ctrl.bits32 = readl(dma_ctrl_reg);
        dma_ctrl.bits.rd_enable = 0;
        dma_ctrl.bits.td_enable = 0;
        writel(dma_ctrl.bits32, dma_ctrl_reg);
}

static int gmac_open(struct net_device *netdev)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        int err;

        if (!netdev->phydev) {
                err = gmac_setup_phy(netdev);
                if (err) {
                        netif_err(port, ifup, netdev,
                                  "PHY init failed: %d\n", err);
                        return err;
                }
        }

        err = request_irq(netdev->irq, gmac_irq,
                          IRQF_SHARED, netdev->name, netdev);
        if (err) {
                netdev_err(netdev, "no IRQ\n");
                return err;
        }

        netif_carrier_off(netdev);
        phy_start(netdev->phydev);

        err = geth_resize_freeq(port);
        /* It's fine if it's just busy, the other port has set up
         * the freeq in that case.
         */
        if (err && (err != -EBUSY)) {
                netdev_err(netdev, "could not resize freeq\n");
                goto err_stop_phy;
        }

        err = gmac_setup_rxq(netdev);
        if (err) {
                netdev_err(netdev, "could not setup RXQ\n");
                goto err_stop_phy;
        }

        err = gmac_setup_txqs(netdev);
        if (err) {
                netdev_err(netdev, "could not setup TXQs\n");
                gmac_cleanup_rxq(netdev);
                goto err_stop_phy;
        }

        napi_enable(&port->napi);

        gmac_start_dma(port);
        gmac_enable_irq(netdev, 1);
        gmac_enable_tx_rx(netdev);
        netif_tx_start_all_queues(netdev);

        hrtimer_init(&port->rx_coalesce_timer, CLOCK_MONOTONIC,
                     HRTIMER_MODE_REL);
        port->rx_coalesce_timer.function = &gmac_coalesce_delay_expired;

        netdev_dbg(netdev, "opened\n");

        return 0;

err_stop_phy:
        phy_stop(netdev->phydev);
        free_irq(netdev->irq, netdev);
        return err;
}

static int gmac_stop(struct net_device *netdev)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);

        hrtimer_cancel(&port->rx_coalesce_timer);
        netif_tx_stop_all_queues(netdev);
        gmac_disable_tx_rx(netdev);
        gmac_stop_dma(port);
        napi_disable(&port->napi);

        gmac_enable_irq(netdev, 0);
        gmac_cleanup_rxq(netdev);
        gmac_cleanup_txqs(netdev);

        phy_stop(netdev->phydev);
        free_irq(netdev->irq, netdev);

        gmac_update_hw_stats(netdev);
        return 0;
}

static void gmac_set_rx_mode(struct net_device *netdev)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        union gmac_rx_fltr filter = { .bits = {
                .broadcast = 1,
                .multicast = 1,
                .unicast = 1,
        } };
        struct netdev_hw_addr *ha;
        unsigned int bit_nr;
        u32 mc_filter[2];

        mc_filter[1] = 0;
        mc_filter[0] = 0;

        if (netdev->flags & IFF_PROMISC) {
                filter.bits.error = 1;
                filter.bits.promiscuous = 1;
                mc_filter[1] = ~0;
                mc_filter[0] = ~0;
        } else if (netdev->flags & IFF_ALLMULTI) {
                mc_filter[1] = ~0;
                mc_filter[0] = ~0;
        } else {
                netdev_for_each_mc_addr(ha, netdev) {
                        bit_nr = ~crc32_le(~0, ha->addr, ETH_ALEN) & 0x3f;
                        mc_filter[bit_nr >> 5] |= 1 << (bit_nr & 0x1f);
                }
        }

        writel(mc_filter[0], port->gmac_base + GMAC_MCAST_FIL0);
        writel(mc_filter[1], port->gmac_base + GMAC_MCAST_FIL1);
        writel(filter.bits32, port->gmac_base + GMAC_RX_FLTR);
}

static void gmac_write_mac_address(struct net_device *netdev)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        __le32 addr[3];

        memset(addr, 0, sizeof(addr));
        memcpy(addr, netdev->dev_addr, ETH_ALEN);

        writel(le32_to_cpu(addr[0]), port->gmac_base + GMAC_STA_ADD0);
        writel(le32_to_cpu(addr[1]), port->gmac_base + GMAC_STA_ADD1);
        writel(le32_to_cpu(addr[2]), port->gmac_base + GMAC_STA_ADD2);
}

static int gmac_set_mac_address(struct net_device *netdev, void *addr)
{
        struct sockaddr *sa = addr;

        memcpy(netdev->dev_addr, sa->sa_data, ETH_ALEN);
        gmac_write_mac_address(netdev);

        return 0;
}

static void gmac_clear_hw_stats(struct net_device *netdev)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);

        readl(port->gmac_base + GMAC_IN_DISCARDS);
        readl(port->gmac_base + GMAC_IN_ERRORS);
        readl(port->gmac_base + GMAC_IN_MCAST);
        readl(port->gmac_base + GMAC_IN_BCAST);
        readl(port->gmac_base + GMAC_IN_MAC1);
        readl(port->gmac_base + GMAC_IN_MAC2);
}

static void gmac_get_stats64(struct net_device *netdev,
                             struct rtnl_link_stats64 *stats)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        unsigned int start;

        gmac_update_hw_stats(netdev);

        /* Racing with RX NAPI */
        do {
                start = u64_stats_fetch_begin(&port->rx_stats_syncp);

                stats->rx_packets = port->stats.rx_packets;
                stats->rx_bytes = port->stats.rx_bytes;
                stats->rx_errors = port->stats.rx_errors;
                stats->rx_dropped = port->stats.rx_dropped;

                stats->rx_length_errors = port->stats.rx_length_errors;
                stats->rx_over_errors = port->stats.rx_over_errors;
                stats->rx_crc_errors = port->stats.rx_crc_errors;
                stats->rx_frame_errors = port->stats.rx_frame_errors;

        } while (u64_stats_fetch_retry(&port->rx_stats_syncp, start));

        /* Racing with MIB and TX completion interrupts */
        do {
                start = u64_stats_fetch_begin(&port->ir_stats_syncp);

                stats->tx_errors = port->stats.tx_errors;
                stats->tx_packets = port->stats.tx_packets;
                stats->tx_bytes = port->stats.tx_bytes;

                stats->multicast = port->stats.multicast;
                stats->rx_missed_errors = port->stats.rx_missed_errors;
                stats->rx_fifo_errors = port->stats.rx_fifo_errors;

        } while (u64_stats_fetch_retry(&port->ir_stats_syncp, start));

        /* Racing with hard_start_xmit */
        do {
                start = u64_stats_fetch_begin(&port->tx_stats_syncp);

                stats->tx_dropped = port->stats.tx_dropped;

        } while (u64_stats_fetch_retry(&port->tx_stats_syncp, start));

        stats->rx_dropped += stats->rx_missed_errors;
}

static int gmac_change_mtu(struct net_device *netdev, int new_mtu)
{
        int max_len = gmac_pick_rx_max_len(new_mtu);

        if (max_len < 0)
                return -EINVAL;

        gmac_disable_tx_rx(netdev);

        netdev->mtu = new_mtu;
        gmac_update_config0_reg(netdev, max_len << CONFIG0_MAXLEN_SHIFT,
                                CONFIG0_MAXLEN_MASK);

        netdev_update_features(netdev);

        gmac_enable_tx_rx(netdev);

        return 0;
}

static netdev_features_t gmac_fix_features(struct net_device *netdev,
                                           netdev_features_t features)
{
        if (netdev->mtu + ETH_HLEN + VLAN_HLEN > MTU_SIZE_BIT_MASK)
                features &= ~GMAC_OFFLOAD_FEATURES;

        return features;
}

static int gmac_set_features(struct net_device *netdev,
                             netdev_features_t features)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        int enable = features & NETIF_F_RXCSUM;
        unsigned long flags;
        u32 reg;

        spin_lock_irqsave(&port->config_lock, flags);

        reg = readl(port->gmac_base + GMAC_CONFIG0);
        reg = enable ? reg | CONFIG0_RX_CHKSUM : reg & ~CONFIG0_RX_CHKSUM;
        writel(reg, port->gmac_base + GMAC_CONFIG0);

        spin_unlock_irqrestore(&port->config_lock, flags);
        return 0;
}

static int gmac_get_sset_count(struct net_device *netdev, int sset)
{
        return sset == ETH_SS_STATS ? GMAC_STATS_NUM : 0;
}

static void gmac_get_strings(struct net_device *netdev, u32 stringset, u8 *data)
{
        if (stringset != ETH_SS_STATS)
                return;

        memcpy(data, gmac_stats_strings, sizeof(gmac_stats_strings));
}

static void gmac_get_ethtool_stats(struct net_device *netdev,
                                   struct ethtool_stats *estats, u64 *values)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        unsigned int start;
        u64 *p;
        int i;

        gmac_update_hw_stats(netdev);

        /* Racing with MIB interrupt */
        do {
                p = values;
                start = u64_stats_fetch_begin(&port->ir_stats_syncp);

                for (i = 0; i < RX_STATS_NUM; i++)
                        *p++ = port->hw_stats[i];

        } while (u64_stats_fetch_retry(&port->ir_stats_syncp, start));
        values = p;

        /* Racing with RX NAPI */
        do {
                p = values;
                start = u64_stats_fetch_begin(&port->rx_stats_syncp);

                for (i = 0; i < RX_STATUS_NUM; i++)
                        *p++ = port->rx_stats[i];
                for (i = 0; i < RX_CHKSUM_NUM; i++)
                        *p++ = port->rx_csum_stats[i];
                *p++ = port->rx_napi_exits;

        } while (u64_stats_fetch_retry(&port->rx_stats_syncp, start));
        values = p;

        /* Racing with TX start_xmit */
        do {
                p = values;
                start = u64_stats_fetch_begin(&port->tx_stats_syncp);

                for (i = 0; i < TX_MAX_FRAGS; i++) {
                        *values++ = port->tx_frag_stats[i];
                        port->tx_frag_stats[i] = 0;
                }
                *values++ = port->tx_frags_linearized;
                *values++ = port->tx_hw_csummed;

        } while (u64_stats_fetch_retry(&port->tx_stats_syncp, start));
}

static int gmac_get_ksettings(struct net_device *netdev,
                              struct ethtool_link_ksettings *cmd)
{
        if (!netdev->phydev)
                return -ENXIO;
        phy_ethtool_ksettings_get(netdev->phydev, cmd);

        return 0;
}

static int gmac_set_ksettings(struct net_device *netdev,
                              const struct ethtool_link_ksettings *cmd)
{
        if (!netdev->phydev)
                return -ENXIO;
        return phy_ethtool_ksettings_set(netdev->phydev, cmd);
}

static int gmac_nway_reset(struct net_device *netdev)
{
        if (!netdev->phydev)
                return -ENXIO;
        return phy_start_aneg(netdev->phydev);
}

static void gmac_get_pauseparam(struct net_device *netdev,
                                struct ethtool_pauseparam *pparam)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        union gmac_config0 config0;

        config0.bits32 = readl(port->gmac_base + GMAC_CONFIG0);

        pparam->rx_pause = config0.bits.rx_fc_en;
        pparam->tx_pause = config0.bits.tx_fc_en;
        pparam->autoneg = true;
}

static void gmac_get_ringparam(struct net_device *netdev,
                               struct ethtool_ringparam *rp)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        union gmac_config0 config0;

        config0.bits32 = readl(port->gmac_base + GMAC_CONFIG0);

        rp->rx_max_pending = 1 << 15;
        rp->rx_mini_max_pending = 0;
        rp->rx_jumbo_max_pending = 0;
        rp->tx_max_pending = 1 << 15;

        rp->rx_pending = 1 << port->rxq_order;
        rp->rx_mini_pending = 0;
        rp->rx_jumbo_pending = 0;
        rp->tx_pending = 1 << port->txq_order;
}

static int gmac_set_ringparam(struct net_device *netdev,
                              struct ethtool_ringparam *rp)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);
        int err = 0;

        if (netif_running(netdev))
                return -EBUSY;

        if (rp->rx_pending) {
                port->rxq_order = min(15, ilog2(rp->rx_pending - 1) + 1);
                err = geth_resize_freeq(port);
        }
        if (rp->tx_pending) {
                port->txq_order = min(15, ilog2(rp->tx_pending - 1) + 1);
                port->irq_every_tx_packets = 1 << (port->txq_order - 2);
        }

        return err;
}

static int gmac_get_coalesce(struct net_device *netdev,
                             struct ethtool_coalesce *ecmd)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);

        ecmd->rx_max_coalesced_frames = 1;
        ecmd->tx_max_coalesced_frames = port->irq_every_tx_packets;
        ecmd->rx_coalesce_usecs = port->rx_coalesce_nsecs / 1000;

        return 0;
}

static int gmac_set_coalesce(struct net_device *netdev,
                             struct ethtool_coalesce *ecmd)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);

        if (ecmd->tx_max_coalesced_frames < 1)
                return -EINVAL;
        if (ecmd->tx_max_coalesced_frames >= 1 << port->txq_order)
                return -EINVAL;

        port->irq_every_tx_packets = ecmd->tx_max_coalesced_frames;
        port->rx_coalesce_nsecs = ecmd->rx_coalesce_usecs * 1000;

        return 0;
}

static u32 gmac_get_msglevel(struct net_device *netdev)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);

        return port->msg_enable;
}

static void gmac_set_msglevel(struct net_device *netdev, u32 level)
{
        struct gemini_ethernet_port *port = netdev_priv(netdev);

        port->msg_enable = level;
}

static void gmac_get_drvinfo(struct net_device *netdev,
                             struct ethtool_drvinfo *info)
{
        strcpy(info->driver,  DRV_NAME);
        strcpy(info->version, DRV_VERSION);
        strcpy(info->bus_info, netdev->dev_id ? "1" : "0");
}

static const struct net_device_ops gmac_351x_ops = {
        .ndo_init               = gmac_init,
        .ndo_uninit             = gmac_uninit,
        .ndo_open               = gmac_open,
        .ndo_stop               = gmac_stop,
        .ndo_start_xmit         = gmac_start_xmit,
        .ndo_tx_timeout         = gmac_tx_timeout,
        .ndo_set_rx_mode        = gmac_set_rx_mode,
        .ndo_set_mac_address    = gmac_set_mac_address,
        .ndo_get_stats64        = gmac_get_stats64,
        .ndo_change_mtu         = gmac_change_mtu,
        .ndo_fix_features       = gmac_fix_features,
        .ndo_set_features       = gmac_set_features,
};

static const struct ethtool_ops gmac_351x_ethtool_ops = {
        .get_sset_count = gmac_get_sset_count,
        .get_strings    = gmac_get_strings,
        .get_ethtool_stats = gmac_get_ethtool_stats,
        .get_link       = ethtool_op_get_link,
        .get_link_ksettings = gmac_get_ksettings,
        .set_link_ksettings = gmac_set_ksettings,
        .nway_reset     = gmac_nway_reset,
        .get_pauseparam = gmac_get_pauseparam,
        .get_ringparam  = gmac_get_ringparam,
        .set_ringparam  = gmac_set_ringparam,
        .get_coalesce   = gmac_get_coalesce,
        .set_coalesce   = gmac_set_coalesce,
        .get_msglevel   = gmac_get_msglevel,
        .set_msglevel   = gmac_set_msglevel,
        .get_drvinfo    = gmac_get_drvinfo,
};

static irqreturn_t gemini_port_irq_thread(int irq, void *data)
{
        unsigned long irqmask = SWFQ_EMPTY_INT_BIT;
        struct gemini_ethernet_port *port = data;
        struct gemini_ethernet *geth;
        unsigned long flags;

        geth = port->geth;
        /* The queue is half empty so refill it */
        geth_fill_freeq(geth, true);

        spin_lock_irqsave(&geth->irq_lock, flags);
        /* ACK queue interrupt */
        writel(irqmask, geth->base + GLOBAL_INTERRUPT_STATUS_4_REG);
        /* Enable queue interrupt again */
        irqmask |= readl(geth->base + GLOBAL_INTERRUPT_ENABLE_4_REG);
        writel(irqmask, geth->base + GLOBAL_INTERRUPT_ENABLE_4_REG);
        spin_unlock_irqrestore(&geth->irq_lock, flags);

        return IRQ_HANDLED;
}

static irqreturn_t gemini_port_irq(int irq, void *data)
{
        struct gemini_ethernet_port *port = data;
        struct gemini_ethernet *geth;
        irqreturn_t ret = IRQ_NONE;
        u32 val, en;

        geth = port->geth;
        spin_lock(&geth->irq_lock);

        val = readl(geth->base + GLOBAL_INTERRUPT_STATUS_4_REG);
        en = readl(geth->base + GLOBAL_INTERRUPT_ENABLE_4_REG);

        if (val & en & SWFQ_EMPTY_INT_BIT) {
                /* Disable the queue empty interrupt while we work on
                 * processing the queue. Also disable overrun interrupts
                 * as there is not much we can do about it here.
                 */
                en &= ~(SWFQ_EMPTY_INT_BIT | GMAC0_RX_OVERRUN_INT_BIT
                                           | GMAC1_RX_OVERRUN_INT_BIT);
                writel(en, geth->base + GLOBAL_INTERRUPT_ENABLE_4_REG);
                ret = IRQ_WAKE_THREAD;
        }

        spin_unlock(&geth->irq_lock);

        return ret;
}

static void gemini_port_remove(struct gemini_ethernet_port *port)
{
        if (port->netdev)
                unregister_netdev(port->netdev);
        clk_disable_unprepare(port->pclk);
        geth_cleanup_freeq(port->geth);
}

static void gemini_ethernet_init(struct gemini_ethernet *geth)
{
        /* Only do this once both ports are online */
        if (geth->initialized)
                return;
        if (geth->port0 && geth->port1)
                geth->initialized = true;
        else
                return;

        writel(0, geth->base + GLOBAL_INTERRUPT_ENABLE_0_REG);
        writel(0, geth->base + GLOBAL_INTERRUPT_ENABLE_1_REG);
        writel(0, geth->base + GLOBAL_INTERRUPT_ENABLE_2_REG);
        writel(0, geth->base + GLOBAL_INTERRUPT_ENABLE_3_REG);
        writel(0, geth->base + GLOBAL_INTERRUPT_ENABLE_4_REG);

        /* Interrupt config:
         *
         *      GMAC0 intr bits ------> int0 ----> eth0
         *      GMAC1 intr bits ------> int1 ----> eth1
         *      TOE intr -------------> int1 ----> eth1
         *      Classification Intr --> int0 ----> eth0
         *      Default Q0 -----------> int0 ----> eth0
         *      Default Q1 -----------> int1 ----> eth1
         *      FreeQ intr -----------> int1 ----> eth1
         */
        writel(0xCCFC0FC0, geth->base + GLOBAL_INTERRUPT_SELECT_0_REG);
        writel(0x00F00002, geth->base + GLOBAL_INTERRUPT_SELECT_1_REG);
        writel(0xFFFFFFFF, geth->base + GLOBAL_INTERRUPT_SELECT_2_REG);
        writel(0xFFFFFFFF, geth->base + GLOBAL_INTERRUPT_SELECT_3_REG);
        writel(0xFF000003, geth->base + GLOBAL_INTERRUPT_SELECT_4_REG);

        /* edge-triggered interrupts packed to level-triggered one... */
        writel(~0, geth->base + GLOBAL_INTERRUPT_STATUS_0_REG);
        writel(~0, geth->base + GLOBAL_INTERRUPT_STATUS_1_REG);
        writel(~0, geth->base + GLOBAL_INTERRUPT_STATUS_2_REG);
        writel(~0, geth->base + GLOBAL_INTERRUPT_STATUS_3_REG);
        writel(~0, geth->base + GLOBAL_INTERRUPT_STATUS_4_REG);

        /* Set up queue */
        writel(0, geth->base + GLOBAL_SW_FREEQ_BASE_SIZE_REG);
        writel(0, geth->base + GLOBAL_HW_FREEQ_BASE_SIZE_REG);
        writel(0, geth->base + GLOBAL_SWFQ_RWPTR_REG);
        writel(0, geth->base + GLOBAL_HWFQ_RWPTR_REG);

        geth->freeq_frag_order = DEFAULT_RX_BUF_ORDER;
        /* This makes the queue resize on probe() so that we
         * set up and enable the queue IRQ. FIXME: fragile.
         */
        geth->freeq_order = 1;
}

static void gemini_port_save_mac_addr(struct gemini_ethernet_port *port)
{
        port->mac_addr[0] =
                cpu_to_le32(readl(port->gmac_base + GMAC_STA_ADD0));
        port->mac_addr[1] =
                cpu_to_le32(readl(port->gmac_base + GMAC_STA_ADD1));
        port->mac_addr[2] =
                cpu_to_le32(readl(port->gmac_base + GMAC_STA_ADD2));
}

static int gemini_ethernet_port_probe(struct platform_device *pdev)
{
        char *port_names[2] = { "ethernet0", "ethernet1" };
        struct gemini_ethernet_port *port;
        struct device *dev = &pdev->dev;
        struct gemini_ethernet *geth;
        struct net_device *netdev;
        struct resource *gmacres;
        struct resource *dmares;
        struct device *parent;
        unsigned int id;
        int irq;
        int ret;

        parent = dev->parent;
        geth = dev_get_drvdata(parent);

        if (!strcmp(dev_name(dev), "60008000.ethernet-port"))
                id = 0;
        else if (!strcmp(dev_name(dev), "6000c000.ethernet-port"))
                id = 1;
        else
                return -ENODEV;

        dev_info(dev, "probe %s ID %d\n", dev_name(dev), id);

        netdev = alloc_etherdev_mq(sizeof(*port), TX_QUEUE_NUM);
        if (!netdev) {
                dev_err(dev, "Can't allocate ethernet device #%d\n", id);
                return -ENOMEM;
        }

        port = netdev_priv(netdev);
        SET_NETDEV_DEV(netdev, dev);
        port->netdev = netdev;
        port->id = id;
        port->geth = geth;
        port->dev = dev;
        port->msg_enable = netif_msg_init(debug, DEFAULT_MSG_ENABLE);

        /* DMA memory */
        dmares = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!dmares) {
                dev_err(dev, "no DMA resource\n");
                return -ENODEV;
        }
        port->dma_base = devm_ioremap_resource(dev, dmares);
        if (IS_ERR(port->dma_base))
                return PTR_ERR(port->dma_base);

        /* GMAC config memory */
        gmacres = platform_get_resource(pdev, IORESOURCE_MEM, 1);
        if (!gmacres) {
                dev_err(dev, "no GMAC resource\n");
                return -ENODEV;
        }
        port->gmac_base = devm_ioremap_resource(dev, gmacres);
        if (IS_ERR(port->gmac_base))
                return PTR_ERR(port->gmac_base);

        /* Interrupt */
        irq = platform_get_irq(pdev, 0);
        if (irq <= 0) {
                dev_err(dev, "no IRQ\n");
                return irq ? irq : -ENODEV;
        }
        port->irq = irq;

        /* Clock the port */
        port->pclk = devm_clk_get(dev, "PCLK");
        if (IS_ERR(port->pclk)) {
                dev_err(dev, "no PCLK\n");
                return PTR_ERR(port->pclk);
        }
        ret = clk_prepare_enable(port->pclk);
        if (ret)
                return ret;

        /* Maybe there is a nice ethernet address we should use */
        gemini_port_save_mac_addr(port);

        /* Reset the port */
        port->reset = devm_reset_control_get_exclusive(dev, NULL);
        if (IS_ERR(port->reset)) {
                dev_err(dev, "no reset\n");
                return PTR_ERR(port->reset);
        }
        reset_control_reset(port->reset);
        usleep_range(100, 500);

        /* Assign pointer in the main state container */
        if (!id)
                geth->port0 = port;
        else
                geth->port1 = port;

        /* This will just be done once both ports are up and reset */
        gemini_ethernet_init(geth);

        platform_set_drvdata(pdev, port);

        /* Set up and register the netdev */
        netdev->dev_id = port->id;
        netdev->irq = irq;
        netdev->netdev_ops = &gmac_351x_ops;
        netdev->ethtool_ops = &gmac_351x_ethtool_ops;

        spin_lock_init(&port->config_lock);
        gmac_clear_hw_stats(netdev);

        netdev->hw_features = GMAC_OFFLOAD_FEATURES;
        netdev->features |= GMAC_OFFLOAD_FEATURES | NETIF_F_GRO;
        /* We can handle jumbo frames up to 10236 bytes so, let's accept
         * payloads of 10236 bytes minus VLAN and ethernet header
         */
        netdev->min_mtu = ETH_MIN_MTU;
        netdev->max_mtu = 10236 - VLAN_ETH_HLEN;

        port->freeq_refill = 0;
        netif_napi_add(netdev, &port->napi, gmac_napi_poll,
                       DEFAULT_NAPI_WEIGHT);

        if (is_valid_ether_addr((void *)port->mac_addr)) {
                memcpy(netdev->dev_addr, port->mac_addr, ETH_ALEN);
        } else {
                dev_dbg(dev, "ethernet address 0x%08x%08x%08x invalid\n",
                        port->mac_addr[0], port->mac_addr[1],
                        port->mac_addr[2]);
                dev_info(dev, "using a random ethernet address\n");
                eth_random_addr(netdev->dev_addr);
        }
        gmac_write_mac_address(netdev);

        ret = devm_request_threaded_irq(port->dev,
                                        port->irq,
                                        gemini_port_irq,
                                        gemini_port_irq_thread,
                                        IRQF_SHARED,
                                        port_names[port->id],
                                        port);
        if (ret)
                return ret;

        ret = register_netdev(netdev);
        if (!ret) {
                netdev_info(netdev,
                            "irq %d, DMA @ 0x%pap, GMAC @ 0x%pap\n",
                            port->irq, &dmares->start,
                            &gmacres->start);
                ret = gmac_setup_phy(netdev);
                if (ret)
                        netdev_info(netdev,
                                    "PHY init failed, deferring to ifup time\n");
                return 0;
        }

        port->netdev = NULL;
        free_netdev(netdev);
        return ret;
}

static int gemini_ethernet_port_remove(struct platform_device *pdev)
{
        struct gemini_ethernet_port *port = platform_get_drvdata(pdev);

        gemini_port_remove(port);
        return 0;
}

static const struct of_device_id gemini_ethernet_port_of_match[] = {
        {
                .compatible = "cortina,gemini-ethernet-port",
        },
        {},
};
MODULE_DEVICE_TABLE(of, gemini_ethernet_port_of_match);

static struct platform_driver gemini_ethernet_port_driver = {
        .driver = {
                .name = "gemini-ethernet-port",
                .of_match_table = of_match_ptr(gemini_ethernet_port_of_match),
        },
        .probe = gemini_ethernet_port_probe,
        .remove = gemini_ethernet_port_remove,
};

static int gemini_ethernet_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct gemini_ethernet *geth;
        unsigned int retry = 5;
        struct resource *res;
        u32 val;

        /* Global registers */
        geth = devm_kzalloc(dev, sizeof(*geth), GFP_KERNEL);
        if (!geth)
                return -ENOMEM;
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res)
                return -ENODEV;
        geth->base = devm_ioremap_resource(dev, res);
        if (IS_ERR(geth->base))
                return PTR_ERR(geth->base);
        geth->dev = dev;

        /* Wait for ports to stabilize */
        do {
                udelay(2);
                val = readl(geth->base + GLOBAL_TOE_VERSION_REG);
                barrier();
        } while (!val && --retry);
        if (!retry) {
                dev_err(dev, "failed to reset ethernet\n");
                return -EIO;
        }
        dev_info(dev, "Ethernet device ID: 0x%03x, revision 0x%01x\n",
                 (val >> 4) & 0xFFFU, val & 0xFU);

        spin_lock_init(&geth->irq_lock);
        spin_lock_init(&geth->freeq_lock);

        /* The children will use this */
        platform_set_drvdata(pdev, geth);

        /* Spawn child devices for the two ports */
        return devm_of_platform_populate(dev);
}

static int gemini_ethernet_remove(struct platform_device *pdev)
{
        struct gemini_ethernet *geth = platform_get_drvdata(pdev);

        geth_cleanup_freeq(geth);
        geth->initialized = false;

        return 0;
}

static const struct of_device_id gemini_ethernet_of_match[] = {
        {
                .compatible = "cortina,gemini-ethernet",
        },
        {},
};
MODULE_DEVICE_TABLE(of, gemini_ethernet_of_match);

static struct platform_driver gemini_ethernet_driver = {
        .driver = {
                .name = DRV_NAME,
                .of_match_table = of_match_ptr(gemini_ethernet_of_match),
        },
        .probe = gemini_ethernet_probe,
        .remove = gemini_ethernet_remove,
};

static int __init gemini_ethernet_module_init(void)
{
        int ret;

        ret = platform_driver_register(&gemini_ethernet_port_driver);
        if (ret)
                return ret;

        ret = platform_driver_register(&gemini_ethernet_driver);
        if (ret) {
                platform_driver_unregister(&gemini_ethernet_port_driver);
                return ret;
        }

        return 0;
}
module_init(gemini_ethernet_module_init);

static void __exit gemini_ethernet_module_exit(void)
{
        platform_driver_unregister(&gemini_ethernet_driver);
        platform_driver_unregister(&gemini_ethernet_port_driver);
}
module_exit(gemini_ethernet_module_exit);

MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
MODULE_DESCRIPTION("StorLink SL351x (Gemini) ethernet driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRV_NAME);