/*
 * Tehuti Networks(R) Network Driver
 * ethtool interface implementation
 * Copyright (C) 2007 Tehuti Networks Ltd. All rights reserved
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

/*
 * RX HW/SW interaction overview
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 * There are 2 types of RX communication channels between driver and NIC.
 * 1) RX Free Fifo - RXF - holds descriptors of empty buffers to accept incoming
 * traffic. This Fifo is filled by SW and is readen by HW. Each descriptor holds
 * info about buffer's location, size and ID. An ID field is used to identify a
 * buffer when it's returned with data via RXD Fifo (see below)
 * 2) RX Data Fifo - RXD - holds descriptors of full buffers. This Fifo is
 * filled by HW and is readen by SW. Each descriptor holds status and ID.
 * HW pops descriptor from RXF Fifo, stores ID, fills buffer with incoming data,
 * via dma moves it into host memory, builds new RXD descriptor with same ID,
 * pushes it into RXD Fifo and raises interrupt to indicate new RX data.
 *
 * Current NIC configuration (registers + firmware) makes NIC use 2 RXF Fifos.
 * One holds 1.5K packets and another - 26K packets. Depending on incoming
 * packet size, HW desides on a RXF Fifo to pop buffer from. When packet is
 * filled with data, HW builds new RXD descriptor for it and push it into single
 * RXD Fifo.
 *
 * RX SW Data Structures
 * ~~~~~~~~~~~~~~~~~~~~~
 * skb db - used to keep track of all skbs owned by SW and their dma addresses.
 * For RX case, ownership lasts from allocating new empty skb for RXF until
 * accepting full skb from RXD and passing it to OS. Each RXF Fifo has its own
 * skb db. Implemented as array with bitmask.
 * fifo - keeps info about fifo's size and location, relevant HW registers,
 * usage and skb db. Each RXD and RXF Fifo has its own fifo structure.
 * Implemented as simple struct.
 *
 * RX SW Execution Flow
 * ~~~~~~~~~~~~~~~~~~~~
 * Upon initialization (ifconfig up) driver creates RX fifos and initializes
 * relevant registers. At the end of init phase, driver enables interrupts.
 * NIC sees that there is no RXF buffers and raises
 * RD_INTR interrupt, isr fills skbs and Rx begins.
 * Driver has two receive operation modes:
 *    NAPI - interrupt-driven mixed with polling
 *    interrupt-driven only
 *
 * Interrupt-driven only flow is following. When buffer is ready, HW raises
 * interrupt and isr is called. isr collects all available packets
 * (bdx_rx_receive), refills skbs (bdx_rx_alloc_skbs) and exit.

 * Rx buffer allocation note
 * ~~~~~~~~~~~~~~~~~~~~~~~~~
 * Driver cares to feed such amount of RxF descriptors that respective amount of
 * RxD descriptors can not fill entire RxD fifo. The main reason is lack of
 * overflow check in Bordeaux for RxD fifo free/used size.
 * FIXME: this is NOT fully implemented, more work should be done
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include "tehuti.h"

static const struct pci_device_id bdx_pci_tbl[] = {
        { PCI_VDEVICE(TEHUTI, 0x3009), },
        { PCI_VDEVICE(TEHUTI, 0x3010), },
        { PCI_VDEVICE(TEHUTI, 0x3014), },
        { 0 }
};

MODULE_DEVICE_TABLE(pci, bdx_pci_tbl);

/* Definitions needed by ISR or NAPI functions */
static void bdx_rx_alloc_skbs(struct bdx_priv *priv, struct rxf_fifo *f);
static void bdx_tx_cleanup(struct bdx_priv *priv);
static int bdx_rx_receive(struct bdx_priv *priv, struct rxd_fifo *f, int budget);

/* Definitions needed by FW loading */
static void bdx_tx_push_desc_safe(struct bdx_priv *priv, void *data, int size);

/* Definitions needed by hw_start */
static int bdx_tx_init(struct bdx_priv *priv);
static int bdx_rx_init(struct bdx_priv *priv);

/* Definitions needed by bdx_close */
static void bdx_rx_free(struct bdx_priv *priv);
static void bdx_tx_free(struct bdx_priv *priv);

/* Definitions needed by bdx_probe */
static void bdx_set_ethtool_ops(struct net_device *netdev);

/*************************************************************************
 *    Print Info                                                         *
 *************************************************************************/

static void print_hw_id(struct pci_dev *pdev)
{
        struct pci_nic *nic = pci_get_drvdata(pdev);
        u16 pci_link_status = 0;
        u16 pci_ctrl = 0;

        pci_read_config_word(pdev, PCI_LINK_STATUS_REG, &pci_link_status);
        pci_read_config_word(pdev, PCI_DEV_CTRL_REG, &pci_ctrl);

        pr_info("%s%s\n", BDX_NIC_NAME,
                nic->port_num == 1 ? "" : ", 2-Port");
        pr_info("srom 0x%x fpga %d build %u lane# %d max_pl 0x%x mrrs 0x%x\n",
                readl(nic->regs + SROM_VER), readl(nic->regs + FPGA_VER) & 0xFFF,
                readl(nic->regs + FPGA_SEED),
                GET_LINK_STATUS_LANES(pci_link_status),
                GET_DEV_CTRL_MAXPL(pci_ctrl), GET_DEV_CTRL_MRRS(pci_ctrl));
}

static void print_fw_id(struct pci_nic *nic)
{
        pr_info("fw 0x%x\n", readl(nic->regs + FW_VER));
}

static void print_eth_id(struct net_device *ndev)
{
        netdev_info(ndev, "%s, Port %c\n",
                    BDX_NIC_NAME, (ndev->if_port == 0) ? 'A' : 'B');

}

/*************************************************************************
 *    Code                                                               *
 *************************************************************************/

#define bdx_enable_interrupts(priv)     \
        do { WRITE_REG(priv, regIMR, IR_RUN); } while (0)
#define bdx_disable_interrupts(priv)    \
        do { WRITE_REG(priv, regIMR, 0); } while (0)

/**
 * bdx_fifo_init - create TX/RX descriptor fifo for host-NIC communication.
 * @priv: NIC private structure
 * @f: fifo to initialize
 * @fsz_type: fifo size type: 0-4KB, 1-8KB, 2-16KB, 3-32KB
 * @reg_XXX: offsets of registers relative to base address
 *
 * 1K extra space is allocated at the end of the fifo to simplify
 * processing of descriptors that wraps around fifo's end
 *
 * Returns 0 on success, negative value on failure
 *
 */
static int
bdx_fifo_init(struct bdx_priv *priv, struct fifo *f, int fsz_type,
              u16 reg_CFG0, u16 reg_CFG1, u16 reg_RPTR, u16 reg_WPTR)
{
        u16 memsz = FIFO_SIZE * (1 << fsz_type);

        memset(f, 0, sizeof(struct fifo));
        /* pci_alloc_consistent gives us 4k-aligned memory */
        f->va = pci_alloc_consistent(priv->pdev,
                                     memsz + FIFO_EXTRA_SPACE, &f->da);
        if (!f->va) {
                pr_err("pci_alloc_consistent failed\n");
                RET(-ENOMEM);
        }
        f->reg_CFG0 = reg_CFG0;
        f->reg_CFG1 = reg_CFG1;
        f->reg_RPTR = reg_RPTR;
        f->reg_WPTR = reg_WPTR;
        f->rptr = 0;
        f->wptr = 0;
        f->memsz = memsz;
        f->size_mask = memsz - 1;
        WRITE_REG(priv, reg_CFG0, (u32) ((f->da & TX_RX_CFG0_BASE) | fsz_type));
        WRITE_REG(priv, reg_CFG1, H32_64(f->da));

        RET(0);
}

/**
 * bdx_fifo_free - free all resources used by fifo
 * @priv: NIC private structure
 * @f: fifo to release
 */
static void bdx_fifo_free(struct bdx_priv *priv, struct fifo *f)
{
        ENTER;
        if (f->va) {
                pci_free_consistent(priv->pdev,
                                    f->memsz + FIFO_EXTRA_SPACE, f->va, f->da);
                f->va = NULL;
        }
        RET();
}

/**
 * bdx_link_changed - notifies OS about hw link state.
 * @priv: hw adapter structure
 */
static void bdx_link_changed(struct bdx_priv *priv)
{
        u32 link = READ_REG(priv, regMAC_LNK_STAT) & MAC_LINK_STAT;

        if (!link) {
                if (netif_carrier_ok(priv->ndev)) {
                        netif_stop_queue(priv->ndev);
                        netif_carrier_off(priv->ndev);
                        netdev_err(priv->ndev, "Link Down\n");
                }
        } else {
                if (!netif_carrier_ok(priv->ndev)) {
                        netif_wake_queue(priv->ndev);
                        netif_carrier_on(priv->ndev);
                        netdev_err(priv->ndev, "Link Up\n");
                }
        }
}

static void bdx_isr_extra(struct bdx_priv *priv, u32 isr)
{
        if (isr & IR_RX_FREE_0) {
                bdx_rx_alloc_skbs(priv, &priv->rxf_fifo0);
                DBG("RX_FREE_0\n");
        }

        if (isr & IR_LNKCHG0)
                bdx_link_changed(priv);

        if (isr & IR_PCIE_LINK)
                netdev_err(priv->ndev, "PCI-E Link Fault\n");

        if (isr & IR_PCIE_TOUT)
                netdev_err(priv->ndev, "PCI-E Time Out\n");

}

/**
 * bdx_isr_napi - Interrupt Service Routine for Bordeaux NIC
 * @irq: interrupt number
 * @dev: network device
 *
 * Return IRQ_NONE if it was not our interrupt, IRQ_HANDLED - otherwise
 *
 * It reads ISR register to know interrupt reasons, and proceed them one by one.
 * Reasons of interest are:
 *    RX_DESC - new packet has arrived and RXD fifo holds its descriptor
 *    RX_FREE - number of free Rx buffers in RXF fifo gets low
 *    TX_FREE - packet was transmited and RXF fifo holds its descriptor
 */

static irqreturn_t bdx_isr_napi(int irq, void *dev)
{
        struct net_device *ndev = dev;
        struct bdx_priv *priv = netdev_priv(ndev);
        u32 isr;

        ENTER;
        isr = (READ_REG(priv, regISR) & IR_RUN);
        if (unlikely(!isr)) {
                bdx_enable_interrupts(priv);
                return IRQ_NONE;        /* Not our interrupt */
        }

        if (isr & IR_EXTRA)
                bdx_isr_extra(priv, isr);

        if (isr & (IR_RX_DESC_0 | IR_TX_FREE_0)) {
                if (likely(napi_schedule_prep(&priv->napi))) {
                        __napi_schedule(&priv->napi);
                        RET(IRQ_HANDLED);
                } else {
                        /* NOTE: we get here if intr has slipped into window
                         * between these lines in bdx_poll:
                         *    bdx_enable_interrupts(priv);
                         *    return 0;
                         * currently intrs are disabled (since we read ISR),
                         * and we have failed to register next poll.
                         * so we read the regs to trigger chip
                         * and allow further interupts. */
                        READ_REG(priv, regTXF_WPTR_0);
                        READ_REG(priv, regRXD_WPTR_0);
                }
        }

        bdx_enable_interrupts(priv);
        RET(IRQ_HANDLED);
}

static int bdx_poll(struct napi_struct *napi, int budget)
{
        struct bdx_priv *priv = container_of(napi, struct bdx_priv, napi);
        int work_done;

        ENTER;
        bdx_tx_cleanup(priv);
        work_done = bdx_rx_receive(priv, &priv->rxd_fifo0, budget);
        if ((work_done < budget) ||
            (priv->napi_stop++ >= 30)) {
                DBG("rx poll is done. backing to isr-driven\n");

                /* from time to time we exit to let NAPI layer release
                 * device lock and allow waiting tasks (eg rmmod) to advance) */
                priv->napi_stop = 0;

                napi_complete_done(napi, work_done);
                bdx_enable_interrupts(priv);
        }
        return work_done;
}

/**
 * bdx_fw_load - loads firmware to NIC
 * @priv: NIC private structure
 *
 * Firmware is loaded via TXD fifo, so it must be initialized first.
 * Firware must be loaded once per NIC not per PCI device provided by NIC (NIC
 * can have few of them). So all drivers use semaphore register to choose one
 * that will actually load FW to NIC.
 */

static int bdx_fw_load(struct bdx_priv *priv)
{
        const struct firmware *fw = NULL;
        int master, i;
        int rc;

        ENTER;
        master = READ_REG(priv, regINIT_SEMAPHORE);
        if (!READ_REG(priv, regINIT_STATUS) && master) {
                rc = request_firmware(&fw, "tehuti/bdx.bin", &priv->pdev->dev);
                if (rc)
                        goto out;
                bdx_tx_push_desc_safe(priv, (char *)fw->data, fw->size);
                mdelay(100);
        }
        for (i = 0; i < 200; i++) {
                if (READ_REG(priv, regINIT_STATUS)) {
                        rc = 0;
                        goto out;
                }
                mdelay(2);
        }
        rc = -EIO;
out:
        if (master)
                WRITE_REG(priv, regINIT_SEMAPHORE, 1);

        release_firmware(fw);

        if (rc) {
                netdev_err(priv->ndev, "firmware loading failed\n");
                if (rc == -EIO)
                        DBG("VPC = 0x%x VIC = 0x%x INIT_STATUS = 0x%x i=%d\n",
                            READ_REG(priv, regVPC),
                            READ_REG(priv, regVIC),
                            READ_REG(priv, regINIT_STATUS), i);
                RET(rc);
        } else {
                DBG("%s: firmware loading success\n", priv->ndev->name);
                RET(0);
        }
}

static void bdx_restore_mac(struct net_device *ndev, struct bdx_priv *priv)
{
        u32 val;

        ENTER;
        DBG("mac0=%x mac1=%x mac2=%x\n",
            READ_REG(priv, regUNC_MAC0_A),
            READ_REG(priv, regUNC_MAC1_A), READ_REG(priv, regUNC_MAC2_A));

        val = (ndev->dev_addr[0] << 8) | (ndev->dev_addr[1]);
        WRITE_REG(priv, regUNC_MAC2_A, val);
        val = (ndev->dev_addr[2] << 8) | (ndev->dev_addr[3]);
        WRITE_REG(priv, regUNC_MAC1_A, val);
        val = (ndev->dev_addr[4] << 8) | (ndev->dev_addr[5]);
        WRITE_REG(priv, regUNC_MAC0_A, val);

        DBG("mac0=%x mac1=%x mac2=%x\n",
            READ_REG(priv, regUNC_MAC0_A),
            READ_REG(priv, regUNC_MAC1_A), READ_REG(priv, regUNC_MAC2_A));
        RET();
}

/**
 * bdx_hw_start - inits registers and starts HW's Rx and Tx engines
 * @priv: NIC private structure
 */
static int bdx_hw_start(struct bdx_priv *priv)
{
        int rc = -EIO;
        struct net_device *ndev = priv->ndev;

        ENTER;
        bdx_link_changed(priv);

        /* 10G overall max length (vlan, eth&ip header, ip payload, crc) */
        WRITE_REG(priv, regFRM_LENGTH, 0X3FE0);
        WRITE_REG(priv, regPAUSE_QUANT, 0x96);
        WRITE_REG(priv, regRX_FIFO_SECTION, 0x800010);
        WRITE_REG(priv, regTX_FIFO_SECTION, 0xE00010);
        WRITE_REG(priv, regRX_FULLNESS, 0);
        WRITE_REG(priv, regTX_FULLNESS, 0);
        WRITE_REG(priv, regCTRLST,
                  regCTRLST_BASE | regCTRLST_RX_ENA | regCTRLST_TX_ENA);

        WRITE_REG(priv, regVGLB, 0);
        WRITE_REG(priv, regMAX_FRAME_A,
                  priv->rxf_fifo0.m.pktsz & MAX_FRAME_AB_VAL);

        DBG("RDINTCM=%08x\n", priv->rdintcm);   /*NOTE: test script uses this */
        WRITE_REG(priv, regRDINTCM0, priv->rdintcm);
        WRITE_REG(priv, regRDINTCM2, 0);        /*cpu_to_le32(rcm.val)); */

        DBG("TDINTCM=%08x\n", priv->tdintcm);   /*NOTE: test script uses this */
        WRITE_REG(priv, regTDINTCM0, priv->tdintcm);    /* old val = 0x300064 */

        /* Enable timer interrupt once in 2 secs. */
        /*WRITE_REG(priv, regGTMR0, ((GTMR_SEC * 2) & GTMR_DATA)); */
        bdx_restore_mac(priv->ndev, priv);

        WRITE_REG(priv, regGMAC_RXF_A, GMAC_RX_FILTER_OSEN |
                  GMAC_RX_FILTER_AM | GMAC_RX_FILTER_AB);

#define BDX_IRQ_TYPE    ((priv->nic->irq_type == IRQ_MSI) ? 0 : IRQF_SHARED)

        rc = request_irq(priv->pdev->irq, bdx_isr_napi, BDX_IRQ_TYPE,
                         ndev->name, ndev);
        if (rc)
                goto err_irq;
        bdx_enable_interrupts(priv);

        RET(0);

err_irq:
        RET(rc);
}

static void bdx_hw_stop(struct bdx_priv *priv)
{
        ENTER;
        bdx_disable_interrupts(priv);
        free_irq(priv->pdev->irq, priv->ndev);

        netif_carrier_off(priv->ndev);
        netif_stop_queue(priv->ndev);

        RET();
}

static int bdx_hw_reset_direct(void __iomem *regs)
{
        u32 val, i;
        ENTER;

        /* reset sequences: read, write 1, read, write 0 */
        val = readl(regs + regCLKPLL);
        writel((val | CLKPLL_SFTRST) + 0x8, regs + regCLKPLL);
        udelay(50);
        val = readl(regs + regCLKPLL);
        writel(val & ~CLKPLL_SFTRST, regs + regCLKPLL);

        /* check that the PLLs are locked and reset ended */
        for (i = 0; i < 70; i++, mdelay(10))
                if ((readl(regs + regCLKPLL) & CLKPLL_LKD) == CLKPLL_LKD) {
                        /* do any PCI-E read transaction */
                        readl(regs + regRXD_CFG0_0);
                        return 0;
                }
        pr_err("HW reset failed\n");
        return 1;               /* failure */
}

static int bdx_hw_reset(struct bdx_priv *priv)
{
        u32 val, i;
        ENTER;

        if (priv->port == 0) {
                /* reset sequences: read, write 1, read, write 0 */
                val = READ_REG(priv, regCLKPLL);
                WRITE_REG(priv, regCLKPLL, (val | CLKPLL_SFTRST) + 0x8);
                udelay(50);
                val = READ_REG(priv, regCLKPLL);
                WRITE_REG(priv, regCLKPLL, val & ~CLKPLL_SFTRST);
        }
        /* check that the PLLs are locked and reset ended */
        for (i = 0; i < 70; i++, mdelay(10))
                if ((READ_REG(priv, regCLKPLL) & CLKPLL_LKD) == CLKPLL_LKD) {
                        /* do any PCI-E read transaction */
                        READ_REG(priv, regRXD_CFG0_0);
                        return 0;
                }
        pr_err("HW reset failed\n");
        return 1;               /* failure */
}

static int bdx_sw_reset(struct bdx_priv *priv)
{
        int i;

        ENTER;
        /* 1. load MAC (obsolete) */
        /* 2. disable Rx (and Tx) */
        WRITE_REG(priv, regGMAC_RXF_A, 0);
        mdelay(100);
        /* 3. disable port */
        WRITE_REG(priv, regDIS_PORT, 1);
        /* 4. disable queue */
        WRITE_REG(priv, regDIS_QU, 1);
        /* 5. wait until hw is disabled */
        for (i = 0; i < 50; i++) {
                if (READ_REG(priv, regRST_PORT) & 1)
                        break;
                mdelay(10);
        }
        if (i == 50)
                netdev_err(priv->ndev, "SW reset timeout. continuing anyway\n");

        /* 6. disable intrs */
        WRITE_REG(priv, regRDINTCM0, 0);
        WRITE_REG(priv, regTDINTCM0, 0);
        WRITE_REG(priv, regIMR, 0);
        READ_REG(priv, regISR);

        /* 7. reset queue */
        WRITE_REG(priv, regRST_QU, 1);
        /* 8. reset port */
        WRITE_REG(priv, regRST_PORT, 1);
        /* 9. zero all read and write pointers */
        for (i = regTXD_WPTR_0; i <= regTXF_RPTR_3; i += 0x10)
                DBG("%x = %x\n", i, READ_REG(priv, i) & TXF_WPTR_WR_PTR);
        for (i = regTXD_WPTR_0; i <= regTXF_RPTR_3; i += 0x10)
                WRITE_REG(priv, i, 0);
        /* 10. unseet port disable */
        WRITE_REG(priv, regDIS_PORT, 0);
        /* 11. unset queue disable */
        WRITE_REG(priv, regDIS_QU, 0);
        /* 12. unset queue reset */
        WRITE_REG(priv, regRST_QU, 0);
        /* 13. unset port reset */
        WRITE_REG(priv, regRST_PORT, 0);
        /* 14. enable Rx */
        /* skiped. will be done later */
        /* 15. save MAC (obsolete) */
        for (i = regTXD_WPTR_0; i <= regTXF_RPTR_3; i += 0x10)
                DBG("%x = %x\n", i, READ_REG(priv, i) & TXF_WPTR_WR_PTR);

        RET(0);
}

/* bdx_reset - performs right type of reset depending on hw type */
static int bdx_reset(struct bdx_priv *priv)
{
        ENTER;
        RET((priv->pdev->device == 0x3009)
            ? bdx_hw_reset(priv)
            : bdx_sw_reset(priv));
}

/**
 * bdx_close - Disables a network interface
 * @netdev: network interface device structure
 *
 * Returns 0, this is not allowed to fail
 *
 * The close entry point is called when an interface is de-activated
 * by the OS.  The hardware is still under the drivers control, but
 * needs to be disabled.  A global MAC reset is issued to stop the
 * hardware, and all transmit and receive resources are freed.
 **/
static int bdx_close(struct net_device *ndev)
{
        struct bdx_priv *priv = NULL;

        ENTER;
        priv = netdev_priv(ndev);

        napi_disable(&priv->napi);

        bdx_reset(priv);
        bdx_hw_stop(priv);
        bdx_rx_free(priv);
        bdx_tx_free(priv);
        RET(0);
}

/**
 * bdx_open - Called when a network interface is made active
 * @netdev: network interface device structure
 *
 * Returns 0 on success, negative value on failure
 *
 * The open entry point is called when a network interface is made
 * active by the system (IFF_UP).  At this point all resources needed
 * for transmit and receive operations are allocated, the interrupt
 * handler is registered with the OS, the watchdog timer is started,
 * and the stack is notified that the interface is ready.
 **/
static int bdx_open(struct net_device *ndev)
{
        struct bdx_priv *priv;
        int rc;

        ENTER;
        priv = netdev_priv(ndev);
        bdx_reset(priv);
        if (netif_running(ndev))
                netif_stop_queue(priv->ndev);

        if ((rc = bdx_tx_init(priv)) ||
            (rc = bdx_rx_init(priv)) ||
            (rc = bdx_fw_load(priv)))
                goto err;

        bdx_rx_alloc_skbs(priv, &priv->rxf_fifo0);

        rc = bdx_hw_start(priv);
        if (rc)
                goto err;

        napi_enable(&priv->napi);

        print_fw_id(priv->nic);

        RET(0);

err:
        bdx_close(ndev);
        RET(rc);
}

static int bdx_range_check(struct bdx_priv *priv, u32 offset)
{
        return (offset > (u32) (BDX_REGS_SIZE / priv->nic->port_num)) ?
                -EINVAL : 0;
}

static int bdx_ioctl_priv(struct net_device *ndev, struct ifreq *ifr, int cmd)
{
        struct bdx_priv *priv = netdev_priv(ndev);
        u32 data[3];
        int error;

        ENTER;

        DBG("jiffies=%ld cmd=%d\n", jiffies, cmd);
        if (cmd != SIOCDEVPRIVATE) {
                error = copy_from_user(data, ifr->ifr_data, sizeof(data));
                if (error) {
                        pr_err("can't copy from user\n");
                        RET(-EFAULT);
                }
                DBG("%d 0x%x 0x%x\n", data[0], data[1], data[2]);
        }

        if (!capable(CAP_SYS_RAWIO))
                return -EPERM;

        switch (data[0]) {

        case BDX_OP_READ:
                error = bdx_range_check(priv, data[1]);
                if (error < 0)
                        return error;
                data[2] = READ_REG(priv, data[1]);
                DBG("read_reg(0x%x)=0x%x (dec %d)\n", data[1], data[2],
                    data[2]);
                error = copy_to_user(ifr->ifr_data, data, sizeof(data));
                if (error)
                        RET(-EFAULT);
                break;

        case BDX_OP_WRITE:
                error = bdx_range_check(priv, data[1]);
                if (error < 0)
                        return error;
                WRITE_REG(priv, data[1], data[2]);
                DBG("write_reg(0x%x, 0x%x)\n", data[1], data[2]);
                break;

        default:
                RET(-EOPNOTSUPP);
        }
        return 0;
}

static int bdx_ioctl(struct net_device *ndev, struct ifreq *ifr, int cmd)
{
        ENTER;
        if (cmd >= SIOCDEVPRIVATE && cmd <= (SIOCDEVPRIVATE + 15))
                RET(bdx_ioctl_priv(ndev, ifr, cmd));
        else
                RET(-EOPNOTSUPP);
}

/**
 * __bdx_vlan_rx_vid - private helper for adding/killing VLAN vid
 * @ndev: network device
 * @vid:  VLAN vid
 * @op:   add or kill operation
 *
 * Passes VLAN filter table to hardware
 */
static void __bdx_vlan_rx_vid(struct net_device *ndev, uint16_t vid, int enable)
{
        struct bdx_priv *priv = netdev_priv(ndev);
        u32 reg, bit, val;

        ENTER;
        DBG2("vid=%d value=%d\n", (int)vid, enable);
        if (unlikely(vid >= 4096)) {
                pr_err("invalid VID: %u (> 4096)\n", vid);
                RET();
        }
        reg = regVLAN_0 + (vid / 32) * 4;
        bit = 1 << vid % 32;
        val = READ_REG(priv, reg);
        DBG2("reg=%x, val=%x, bit=%d\n", reg, val, bit);
        if (enable)
                val |= bit;
        else
                val &= ~bit;
        DBG2("new val %x\n", val);
        WRITE_REG(priv, reg, val);
        RET();
}

/**
 * bdx_vlan_rx_add_vid - kernel hook for adding VLAN vid to hw filtering table
 * @ndev: network device
 * @vid:  VLAN vid to add
 */
static int bdx_vlan_rx_add_vid(struct net_device *ndev, __be16 proto, u16 vid)
{
        __bdx_vlan_rx_vid(ndev, vid, 1);
        return 0;
}

/**
 * bdx_vlan_rx_kill_vid - kernel hook for killing VLAN vid in hw filtering table
 * @ndev: network device
 * @vid:  VLAN vid to kill
 */
static int bdx_vlan_rx_kill_vid(struct net_device *ndev, __be16 proto, u16 vid)
{
        __bdx_vlan_rx_vid(ndev, vid, 0);
        return 0;
}

/**
 * bdx_change_mtu - Change the Maximum Transfer Unit
 * @netdev: network interface device structure
 * @new_mtu: new value for maximum frame size
 *
 * Returns 0 on success, negative on failure
 */
static int bdx_change_mtu(struct net_device *ndev, int new_mtu)
{
        ENTER;

        ndev->mtu = new_mtu;
        if (netif_running(ndev)) {
                bdx_close(ndev);
                bdx_open(ndev);
        }
        RET(0);
}

static void bdx_setmulti(struct net_device *ndev)
{
        struct bdx_priv *priv = netdev_priv(ndev);

        u32 rxf_val =
            GMAC_RX_FILTER_AM | GMAC_RX_FILTER_AB | GMAC_RX_FILTER_OSEN;
        int i;

        ENTER;
        /* IMF - imperfect (hash) rx multicat filter */
        /* PMF - perfect rx multicat filter */

        /* FIXME: RXE(OFF) */
        if (ndev->flags & IFF_PROMISC) {
                rxf_val |= GMAC_RX_FILTER_PRM;
        } else if (ndev->flags & IFF_ALLMULTI) {
                /* set IMF to accept all multicast frmaes */
                for (i = 0; i < MAC_MCST_HASH_NUM; i++)
                        WRITE_REG(priv, regRX_MCST_HASH0 + i * 4, ~0);
        } else if (!netdev_mc_empty(ndev)) {
                u8 hash;
                struct netdev_hw_addr *ha;
                u32 reg, val;

                /* set IMF to deny all multicast frames */
                for (i = 0; i < MAC_MCST_HASH_NUM; i++)
                        WRITE_REG(priv, regRX_MCST_HASH0 + i * 4, 0);
                /* set PMF to deny all multicast frames */
                for (i = 0; i < MAC_MCST_NUM; i++) {
                        WRITE_REG(priv, regRX_MAC_MCST0 + i * 8, 0);
                        WRITE_REG(priv, regRX_MAC_MCST1 + i * 8, 0);
                }

                /* use PMF to accept first MAC_MCST_NUM (15) addresses */
                /* TBD: sort addresses and write them in ascending order
                 * into RX_MAC_MCST regs. we skip this phase now and accept ALL
                 * multicast frames throu IMF */
                /* accept the rest of addresses throu IMF */
                netdev_for_each_mc_addr(ha, ndev) {
                        hash = 0;
                        for (i = 0; i < ETH_ALEN; i++)
                                hash ^= ha->addr[i];
                        reg = regRX_MCST_HASH0 + ((hash >> 5) << 2);
                        val = READ_REG(priv, reg);
                        val |= (1 << (hash % 32));
                        WRITE_REG(priv, reg, val);
                }

        } else {
                DBG("only own mac %d\n", netdev_mc_count(ndev));
                rxf_val |= GMAC_RX_FILTER_AB;
        }
        WRITE_REG(priv, regGMAC_RXF_A, rxf_val);
        /* enable RX */
        /* FIXME: RXE(ON) */
        RET();
}

static int bdx_set_mac(struct net_device *ndev, void *p)
{
        struct bdx_priv *priv = netdev_priv(ndev);
        struct sockaddr *addr = p;

        ENTER;
        /*
           if (netif_running(dev))
           return -EBUSY
         */
        memcpy(ndev->dev_addr, addr->sa_data, ndev->addr_len);
        bdx_restore_mac(ndev, priv);
        RET(0);
}

static int bdx_read_mac(struct bdx_priv *priv)
{
        u16 macAddress[3], i;
        ENTER;

        macAddress[2] = READ_REG(priv, regUNC_MAC0_A);
        macAddress[2] = READ_REG(priv, regUNC_MAC0_A);
        macAddress[1] = READ_REG(priv, regUNC_MAC1_A);
        macAddress[1] = READ_REG(priv, regUNC_MAC1_A);
        macAddress[0] = READ_REG(priv, regUNC_MAC2_A);
        macAddress[0] = READ_REG(priv, regUNC_MAC2_A);
        for (i = 0; i < 3; i++) {
                priv->ndev->dev_addr[i * 2 + 1] = macAddress[i];
                priv->ndev->dev_addr[i * 2] = macAddress[i] >> 8;
        }
        RET(0);
}

static u64 bdx_read_l2stat(struct bdx_priv *priv, int reg)
{
        u64 val;

        val = READ_REG(priv, reg);
        val |= ((u64) READ_REG(priv, reg + 8)) << 32;
        return val;
}

/*Do the statistics-update work*/
static void bdx_update_stats(struct bdx_priv *priv)
{
        struct bdx_stats *stats = &priv->hw_stats;
        u64 *stats_vector = (u64 *) stats;
        int i;
        int addr;

        /*Fill HW structure */
        addr = 0x7200;
        /*First 12 statistics - 0x7200 - 0x72B0 */
        for (i = 0; i < 12; i++) {
                stats_vector[i] = bdx_read_l2stat(priv, addr);
                addr += 0x10;
        }
        BDX_ASSERT(addr != 0x72C0);
        /* 0x72C0-0x72E0 RSRV */
        addr = 0x72F0;
        for (; i < 16; i++) {
                stats_vector[i] = bdx_read_l2stat(priv, addr);
                addr += 0x10;
        }
        BDX_ASSERT(addr != 0x7330);
        /* 0x7330-0x7360 RSRV */
        addr = 0x7370;
        for (; i < 19; i++) {
                stats_vector[i] = bdx_read_l2stat(priv, addr);
                addr += 0x10;
        }
        BDX_ASSERT(addr != 0x73A0);
        /* 0x73A0-0x73B0 RSRV */
        addr = 0x73C0;
        for (; i < 23; i++) {
                stats_vector[i] = bdx_read_l2stat(priv, addr);
                addr += 0x10;
        }
        BDX_ASSERT(addr != 0x7400);
        BDX_ASSERT((sizeof(struct bdx_stats) / sizeof(u64)) != i);
}

static void print_rxdd(struct rxd_desc *rxdd, u32 rxd_val1, u16 len,
                       u16 rxd_vlan);
static void print_rxfd(struct rxf_desc *rxfd);

/*************************************************************************
 *     Rx DB                                                             *
 *************************************************************************/

static void bdx_rxdb_destroy(struct rxdb *db)
{
        vfree(db);
}

static struct rxdb *bdx_rxdb_create(int nelem)
{
        struct rxdb *db;
        int i;

        db = vmalloc(sizeof(struct rxdb)
                     + (nelem * sizeof(int))
                     + (nelem * sizeof(struct rx_map)));
        if (likely(db != NULL)) {
                db->stack = (int *)(db + 1);
                db->elems = (void *)(db->stack + nelem);
                db->nelem = nelem;
                db->top = nelem;
                for (i = 0; i < nelem; i++)
                        db->stack[i] = nelem - i - 1;   /* to make first allocs
                                                           close to db struct*/
        }

        return db;
}

static inline int bdx_rxdb_alloc_elem(struct rxdb *db)
{
        BDX_ASSERT(db->top <= 0);
        return db->stack[--(db->top)];
}

static inline void *bdx_rxdb_addr_elem(struct rxdb *db, int n)
{
        BDX_ASSERT((n < 0) || (n >= db->nelem));
        return db->elems + n;
}

static inline int bdx_rxdb_available(struct rxdb *db)
{
        return db->top;
}

static inline void bdx_rxdb_free_elem(struct rxdb *db, int n)
{
        BDX_ASSERT((n >= db->nelem) || (n < 0));
        db->stack[(db->top)++] = n;
}

/*************************************************************************
 *     Rx Init                                                           *
 *************************************************************************/

/**
 * bdx_rx_init - initialize RX all related HW and SW resources
 * @priv: NIC private structure
 *
 * Returns 0 on success, negative value on failure
 *
 * It creates rxf and rxd fifos, update relevant HW registers, preallocate
 * skb for rx. It assumes that Rx is desabled in HW
 * funcs are grouped for better cache usage
 *
 * RxD fifo is smaller than RxF fifo by design. Upon high load, RxD will be
 * filled and packets will be dropped by nic without getting into host or
 * cousing interrupt. Anyway, in that condition, host has no chance to process
 * all packets, but dropping in nic is cheaper, since it takes 0 cpu cycles
 */

/* TBD: ensure proper packet size */

static int bdx_rx_init(struct bdx_priv *priv)
{
        ENTER;

        if (bdx_fifo_init(priv, &priv->rxd_fifo0.m, priv->rxd_size,
                          regRXD_CFG0_0, regRXD_CFG1_0,
                          regRXD_RPTR_0, regRXD_WPTR_0))
                goto err_mem;
        if (bdx_fifo_init(priv, &priv->rxf_fifo0.m, priv->rxf_size,
                          regRXF_CFG0_0, regRXF_CFG1_0,

                          regRXF_RPTR_0, regRXF_WPTR_0))
                goto err_mem;
        priv->rxdb = bdx_rxdb_create(priv->rxf_fifo0.m.memsz /
                                     sizeof(struct rxf_desc));
        if (!priv->rxdb)
                goto err_mem;

        priv->rxf_fifo0.m.pktsz = priv->ndev->mtu + VLAN_ETH_HLEN;
        return 0;

err_mem:
        netdev_err(priv->ndev, "Rx init failed\n");
        return -ENOMEM;
}

/**
 * bdx_rx_free_skbs - frees and unmaps all skbs allocated for the fifo
 * @priv: NIC private structure
 * @f: RXF fifo
 */
static void bdx_rx_free_skbs(struct bdx_priv *priv, struct rxf_fifo *f)
{
        struct rx_map *dm;
        struct rxdb *db = priv->rxdb;
        u16 i;

        ENTER;
        DBG("total=%d free=%d busy=%d\n", db->nelem, bdx_rxdb_available(db),
            db->nelem - bdx_rxdb_available(db));
        while (bdx_rxdb_available(db) > 0) {
                i = bdx_rxdb_alloc_elem(db);
                dm = bdx_rxdb_addr_elem(db, i);
                dm->dma = 0;
        }
        for (i = 0; i < db->nelem; i++) {
                dm = bdx_rxdb_addr_elem(db, i);
                if (dm->dma) {
                        pci_unmap_single(priv->pdev,
                                         dm->dma, f->m.pktsz,
                                         PCI_DMA_FROMDEVICE);
                        dev_kfree_skb(dm->skb);
                }
        }
}

/**
 * bdx_rx_free - release all Rx resources
 * @priv: NIC private structure
 *
 * It assumes that Rx is desabled in HW
 */
static void bdx_rx_free(struct bdx_priv *priv)
{
        ENTER;
        if (priv->rxdb) {
                bdx_rx_free_skbs(priv, &priv->rxf_fifo0);
                bdx_rxdb_destroy(priv->rxdb);
                priv->rxdb = NULL;
        }
        bdx_fifo_free(priv, &priv->rxf_fifo0.m);
        bdx_fifo_free(priv, &priv->rxd_fifo0.m);

        RET();
}

/*************************************************************************
 *     Rx Engine                                                         *
 *************************************************************************/

/**
 * bdx_rx_alloc_skbs - fill rxf fifo with new skbs
 * @priv: nic's private structure
 * @f: RXF fifo that needs skbs
 *
 * It allocates skbs, build rxf descs and push it (rxf descr) into rxf fifo.
 * skb's virtual and physical addresses are stored in skb db.
 * To calculate free space, func uses cached values of RPTR and WPTR
 * When needed, it also updates RPTR and WPTR.
 */

/* TBD: do not update WPTR if no desc were written */

static void bdx_rx_alloc_skbs(struct bdx_priv *priv, struct rxf_fifo *f)
{
        struct sk_buff *skb;
        struct rxf_desc *rxfd;
        struct rx_map *dm;
        int dno, delta, idx;
        struct rxdb *db = priv->rxdb;

        ENTER;
        dno = bdx_rxdb_available(db) - 1;
        while (dno > 0) {
                skb = netdev_alloc_skb(priv->ndev, f->m.pktsz + NET_IP_ALIGN);
                if (!skb)
                        break;

                skb_reserve(skb, NET_IP_ALIGN);

                idx = bdx_rxdb_alloc_elem(db);
                dm = bdx_rxdb_addr_elem(db, idx);
                dm->dma = pci_map_single(priv->pdev,
                                         skb->data, f->m.pktsz,
                                         PCI_DMA_FROMDEVICE);
                dm->skb = skb;
                rxfd = (struct rxf_desc *)(f->m.va + f->m.wptr);
                rxfd->info = CPU_CHIP_SWAP32(0x10003);  /* INFO=1 BC=3 */
                rxfd->va_lo = idx;
                rxfd->pa_lo = CPU_CHIP_SWAP32(L32_64(dm->dma));
                rxfd->pa_hi = CPU_CHIP_SWAP32(H32_64(dm->dma));
                rxfd->len = CPU_CHIP_SWAP32(f->m.pktsz);
                print_rxfd(rxfd);

                f->m.wptr += sizeof(struct rxf_desc);
                delta = f->m.wptr - f->m.memsz;
                if (unlikely(delta >= 0)) {
                        f->m.wptr = delta;
                        if (delta > 0) {
                                memcpy(f->m.va, f->m.va + f->m.memsz, delta);
                                DBG("wrapped descriptor\n");
                        }
                }
                dno--;
        }
        /*TBD: to do - delayed rxf wptr like in txd */
        WRITE_REG(priv, f->m.reg_WPTR, f->m.wptr & TXF_WPTR_WR_PTR);
        RET();
}

static inline void
NETIF_RX_MUX(struct bdx_priv *priv, u32 rxd_val1, u16 rxd_vlan,
             struct sk_buff *skb)
{
        ENTER;
        DBG("rxdd->flags.bits.vtag=%d\n", GET_RXD_VTAG(rxd_val1));
        if (GET_RXD_VTAG(rxd_val1)) {
                DBG("%s: vlan rcv vlan '%x' vtag '%x'\n",
                    priv->ndev->name,
                    GET_RXD_VLAN_ID(rxd_vlan),
                    GET_RXD_VTAG(rxd_val1));
                __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), GET_RXD_VLAN_TCI(rxd_vlan));
        }
        netif_receive_skb(skb);
}

static void bdx_recycle_skb(struct bdx_priv *priv, struct rxd_desc *rxdd)
{
        struct rxf_desc *rxfd;
        struct rx_map *dm;
        struct rxf_fifo *f;
        struct rxdb *db;
        struct sk_buff *skb;
        int delta;

        ENTER;
        DBG("priv=%p rxdd=%p\n", priv, rxdd);
        f = &priv->rxf_fifo0;
        db = priv->rxdb;
        DBG("db=%p f=%p\n", db, f);
        dm = bdx_rxdb_addr_elem(db, rxdd->va_lo);
        DBG("dm=%p\n", dm);
        skb = dm->skb;
        rxfd = (struct rxf_desc *)(f->m.va + f->m.wptr);
        rxfd->info = CPU_CHIP_SWAP32(0x10003);  /* INFO=1 BC=3 */
        rxfd->va_lo = rxdd->va_lo;
        rxfd->pa_lo = CPU_CHIP_SWAP32(L32_64(dm->dma));
        rxfd->pa_hi = CPU_CHIP_SWAP32(H32_64(dm->dma));
        rxfd->len = CPU_CHIP_SWAP32(f->m.pktsz);
        print_rxfd(rxfd);

        f->m.wptr += sizeof(struct rxf_desc);
        delta = f->m.wptr - f->m.memsz;
        if (unlikely(delta >= 0)) {
                f->m.wptr = delta;
                if (delta > 0) {
                        memcpy(f->m.va, f->m.va + f->m.memsz, delta);
                        DBG("wrapped descriptor\n");
                }
        }
        RET();
}

/**
 * bdx_rx_receive - receives full packets from RXD fifo and pass them to OS
 * NOTE: a special treatment is given to non-continuous descriptors
 * that start near the end, wraps around and continue at the beginning. a second
 * part is copied right after the first, and then descriptor is interpreted as
 * normal. fifo has an extra space to allow such operations
 * @priv: nic's private structure
 * @f: RXF fifo that needs skbs
 * @budget: maximum number of packets to receive
 */

/* TBD: replace memcpy func call by explicite inline asm */

static int bdx_rx_receive(struct bdx_priv *priv, struct rxd_fifo *f, int budget)
{
        struct net_device *ndev = priv->ndev;
        struct sk_buff *skb, *skb2;
        struct rxd_desc *rxdd;
        struct rx_map *dm;
        struct rxf_fifo *rxf_fifo;
        int tmp_len, size;
        int done = 0;
        int max_done = BDX_MAX_RX_DONE;
        struct rxdb *db = NULL;
        /* Unmarshalled descriptor - copy of descriptor in host order */
        u32 rxd_val1;
        u16 len;
        u16 rxd_vlan;

        ENTER;
        max_done = budget;

        f->m.wptr = READ_REG(priv, f->m.reg_WPTR) & TXF_WPTR_WR_PTR;

        size = f->m.wptr - f->m.rptr;
        if (size < 0)
                size = f->m.memsz + size;       /* size is negative :-) */

        while (size > 0) {

                rxdd = (struct rxd_desc *)(f->m.va + f->m.rptr);
                rxd_val1 = CPU_CHIP_SWAP32(rxdd->rxd_val1);

                len = CPU_CHIP_SWAP16(rxdd->len);

                rxd_vlan = CPU_CHIP_SWAP16(rxdd->rxd_vlan);

                print_rxdd(rxdd, rxd_val1, len, rxd_vlan);

                tmp_len = GET_RXD_BC(rxd_val1) << 3;
                BDX_ASSERT(tmp_len <= 0);
                size -= tmp_len;
                if (size < 0)   /* test for partially arrived descriptor */
                        break;

                f->m.rptr += tmp_len;

                tmp_len = f->m.rptr - f->m.memsz;
                if (unlikely(tmp_len >= 0)) {
                        f->m.rptr = tmp_len;
                        if (tmp_len > 0) {
                                DBG("wrapped desc rptr=%d tmp_len=%d\n",
                                    f->m.rptr, tmp_len);
                                memcpy(f->m.va + f->m.memsz, f->m.va, tmp_len);
                        }
                }

                if (unlikely(GET_RXD_ERR(rxd_val1))) {
                        DBG("rxd_err = 0x%x\n", GET_RXD_ERR(rxd_val1));
                        ndev->stats.rx_errors++;
                        bdx_recycle_skb(priv, rxdd);
                        continue;
                }

                rxf_fifo = &priv->rxf_fifo0;
                db = priv->rxdb;
                dm = bdx_rxdb_addr_elem(db, rxdd->va_lo);
                skb = dm->skb;

                if (len < BDX_COPYBREAK &&
                    (skb2 = netdev_alloc_skb(priv->ndev, len + NET_IP_ALIGN))) {
                        skb_reserve(skb2, NET_IP_ALIGN);
                        /*skb_put(skb2, len); */
                        pci_dma_sync_single_for_cpu(priv->pdev,
                                                    dm->dma, rxf_fifo->m.pktsz,
                                                    PCI_DMA_FROMDEVICE);
                        memcpy(skb2->data, skb->data, len);
                        bdx_recycle_skb(priv, rxdd);
                        skb = skb2;
                } else {
                        pci_unmap_single(priv->pdev,
                                         dm->dma, rxf_fifo->m.pktsz,
                                         PCI_DMA_FROMDEVICE);
                        bdx_rxdb_free_elem(db, rxdd->va_lo);
                }

                ndev->stats.rx_bytes += len;

                skb_put(skb, len);
                skb->protocol = eth_type_trans(skb, ndev);

                /* Non-IP packets aren't checksum-offloaded */
                if (GET_RXD_PKT_ID(rxd_val1) == 0)
                        skb_checksum_none_assert(skb);
                else
                        skb->ip_summed = CHECKSUM_UNNECESSARY;

                NETIF_RX_MUX(priv, rxd_val1, rxd_vlan, skb);

                if (++done >= max_done)
                        break;
        }

        ndev->stats.rx_packets += done;

        /* FIXME: do smth to minimize pci accesses    */
        WRITE_REG(priv, f->m.reg_RPTR, f->m.rptr & TXF_WPTR_WR_PTR);

        bdx_rx_alloc_skbs(priv, &priv->rxf_fifo0);

        RET(done);
}

/*************************************************************************
 * Debug / Temprorary Code                                               *
 *************************************************************************/
static void print_rxdd(struct rxd_desc *rxdd, u32 rxd_val1, u16 len,
                       u16 rxd_vlan)
{
        DBG("ERROR: rxdd bc %d rxfq %d to %d type %d err %d rxp %d pkt_id %d vtag %d len %d vlan_id %d cfi %d prio %d va_lo %d va_hi %d\n",
            GET_RXD_BC(rxd_val1), GET_RXD_RXFQ(rxd_val1), GET_RXD_TO(rxd_val1),
            GET_RXD_TYPE(rxd_val1), GET_RXD_ERR(rxd_val1),
            GET_RXD_RXP(rxd_val1), GET_RXD_PKT_ID(rxd_val1),
            GET_RXD_VTAG(rxd_val1), len, GET_RXD_VLAN_ID(rxd_vlan),
            GET_RXD_CFI(rxd_vlan), GET_RXD_PRIO(rxd_vlan), rxdd->va_lo,
            rxdd->va_hi);
}

static void print_rxfd(struct rxf_desc *rxfd)
{
        DBG("=== RxF desc CHIP ORDER/ENDIANNESS =============\n"
            "info 0x%x va_lo %u pa_lo 0x%x pa_hi 0x%x len 0x%x\n",
            rxfd->info, rxfd->va_lo, rxfd->pa_lo, rxfd->pa_hi, rxfd->len);
}

/*
 * TX HW/SW interaction overview
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 * There are 2 types of TX communication channels between driver and NIC.
 * 1) TX Free Fifo - TXF - holds ack descriptors for sent packets
 * 2) TX Data Fifo - TXD - holds descriptors of full buffers.
 *
 * Currently NIC supports TSO, checksuming and gather DMA
 * UFO and IP fragmentation is on the way
 *
 * RX SW Data Structures
 * ~~~~~~~~~~~~~~~~~~~~~
 * txdb - used to keep track of all skbs owned by SW and their dma addresses.
 * For TX case, ownership lasts from geting packet via hard_xmit and until HW
 * acknowledges sent by TXF descriptors.
 * Implemented as cyclic buffer.
 * fifo - keeps info about fifo's size and location, relevant HW registers,
 * usage and skb db. Each RXD and RXF Fifo has its own fifo structure.
 * Implemented as simple struct.
 *
 * TX SW Execution Flow
 * ~~~~~~~~~~~~~~~~~~~~
 * OS calls driver's hard_xmit method with packet to sent.
 * Driver creates DMA mappings, builds TXD descriptors and kicks HW
 * by updating TXD WPTR.
 * When packet is sent, HW write us TXF descriptor and SW frees original skb.
 * To prevent TXD fifo overflow without reading HW registers every time,
 * SW deploys "tx level" technique.
 * Upon strart up, tx level is initialized to TXD fifo length.
 * For every sent packet, SW gets its TXD descriptor sizei
 * (from precalculated array) and substructs it from tx level.
 * The size is also stored in txdb. When TXF ack arrives, SW fetch size of
 * original TXD descriptor from txdb and adds it to tx level.
 * When Tx level drops under some predefined treshhold, the driver
 * stops the TX queue. When TX level rises above that level,
 * the tx queue is enabled again.
 *
 * This technique avoids eccessive reading of RPTR and WPTR registers.
 * As our benchmarks shows, it adds 1.5 Gbit/sec to NIS's throuput.
 */

/*************************************************************************
 *     Tx DB                                                             *
 *************************************************************************/
static inline int bdx_tx_db_size(struct txdb *db)
{
        int taken = db->wptr - db->rptr;
        if (taken < 0)
                taken = db->size + 1 + taken;   /* (size + 1) equals memsz */

        return db->size - taken;
}

/**
 * __bdx_tx_db_ptr_next - helper function, increment read/write pointer + wrap
 * @db: tx data base
 * @pptr: read or write pointer
 */
static inline void __bdx_tx_db_ptr_next(struct txdb *db, struct tx_map **pptr)
{
        BDX_ASSERT(db == NULL || pptr == NULL); /* sanity */

        BDX_ASSERT(*pptr != db->rptr && /* expect either read */
                   *pptr != db->wptr);  /* or write pointer */

        BDX_ASSERT(*pptr < db->start || /* pointer has to be */
                   *pptr >= db->end);   /* in range */

        ++*pptr;
        if (unlikely(*pptr == db->end))
                *pptr = db->start;
}

/**
 * bdx_tx_db_inc_rptr - increment read pointer
 * @db: tx data base
 */
static inline void bdx_tx_db_inc_rptr(struct txdb *db)
{
        BDX_ASSERT(db->rptr == db->wptr);       /* can't read from empty db */
        __bdx_tx_db_ptr_next(db, &db->rptr);
}

/**
 * bdx_tx_db_inc_wptr - increment write pointer
 * @db: tx data base
 */
static inline void bdx_tx_db_inc_wptr(struct txdb *db)
{
        __bdx_tx_db_ptr_next(db, &db->wptr);
        BDX_ASSERT(db->rptr == db->wptr);       /* we can not get empty db as
                                                   a result of write */
}

/**
 * bdx_tx_db_init - creates and initializes tx db
 * @d: tx data base
 * @sz_type: size of tx fifo
 *
 * Returns 0 on success, error code otherwise
 */
static int bdx_tx_db_init(struct txdb *d, int sz_type)
{
        int memsz = FIFO_SIZE * (1 << (sz_type + 1));

        d->start = vmalloc(memsz);
        if (!d->start)
                return -ENOMEM;

        /*
         * In order to differentiate between db is empty and db is full
         * states at least one element should always be empty in order to
         * avoid rptr == wptr which means db is empty
         */
        d->size = memsz / sizeof(struct tx_map) - 1;
        d->end = d->start + d->size + 1;        /* just after last element */

        /* all dbs are created equally empty */
        d->rptr = d->start;
        d->wptr = d->start;

        return 0;
}

/**
 * bdx_tx_db_close - closes tx db and frees all memory
 * @d: tx data base
 */
static void bdx_tx_db_close(struct txdb *d)
{
        BDX_ASSERT(d == NULL);

        vfree(d->start);
        d->start = NULL;
}

/*************************************************************************
 *     Tx Engine                                                         *
 *************************************************************************/

/* sizes of tx desc (including padding if needed) as function
 * of skb's frag number */
static struct {
        u16 bytes;
        u16 qwords;             /* qword = 64 bit */
} txd_sizes[MAX_SKB_FRAGS + 1];

/**
 * bdx_tx_map_skb - creates and stores dma mappings for skb's data blocks
 * @priv: NIC private structure
 * @skb: socket buffer to map
 * @txdd: TX descriptor to use
 *
 * It makes dma mappings for skb's data blocks and writes them to PBL of
 * new tx descriptor. It also stores them in the tx db, so they could be
 * unmaped after data was sent. It is reponsibility of a caller to make
 * sure that there is enough space in the tx db. Last element holds pointer
 * to skb itself and marked with zero length
 */
static inline void
bdx_tx_map_skb(struct bdx_priv *priv, struct sk_buff *skb,
               struct txd_desc *txdd)
{
        struct txdb *db = &priv->txdb;
        struct pbl *pbl = &txdd->pbl[0];
        int nr_frags = skb_shinfo(skb)->nr_frags;
        int i;

        db->wptr->len = skb_headlen(skb);
        db->wptr->addr.dma = pci_map_single(priv->pdev, skb->data,
                                            db->wptr->len, PCI_DMA_TODEVICE);
        pbl->len = CPU_CHIP_SWAP32(db->wptr->len);
        pbl->pa_lo = CPU_CHIP_SWAP32(L32_64(db->wptr->addr.dma));
        pbl->pa_hi = CPU_CHIP_SWAP32(H32_64(db->wptr->addr.dma));
        DBG("=== pbl   len: 0x%x ================\n", pbl->len);
        DBG("=== pbl pa_lo: 0x%x ================\n", pbl->pa_lo);
        DBG("=== pbl pa_hi: 0x%x ================\n", pbl->pa_hi);
        bdx_tx_db_inc_wptr(db);

        for (i = 0; i < nr_frags; i++) {
                const struct skb_frag_struct *frag;

                frag = &skb_shinfo(skb)->frags[i];
                db->wptr->len = skb_frag_size(frag);
                db->wptr->addr.dma = skb_frag_dma_map(&priv->pdev->dev, frag,
                                                      0, skb_frag_size(frag),
                                                      DMA_TO_DEVICE);

                pbl++;
                pbl->len = CPU_CHIP_SWAP32(db->wptr->len);
                pbl->pa_lo = CPU_CHIP_SWAP32(L32_64(db->wptr->addr.dma));
                pbl->pa_hi = CPU_CHIP_SWAP32(H32_64(db->wptr->addr.dma));
                bdx_tx_db_inc_wptr(db);
        }

        /* add skb clean up info. */
        db->wptr->len = -txd_sizes[nr_frags].bytes;
        db->wptr->addr.skb = skb;
        bdx_tx_db_inc_wptr(db);
}

/* init_txd_sizes - precalculate sizes of descriptors for skbs up to 16 frags
 * number of frags is used as index to fetch correct descriptors size,
 * instead of calculating it each time */
static void __init init_txd_sizes(void)
{
        int i, lwords;

        /* 7 - is number of lwords in txd with one phys buffer
         * 3 - is number of lwords used for every additional phys buffer */
        for (i = 0; i < MAX_SKB_FRAGS + 1; i++) {
                lwords = 7 + (i * 3);
                if (lwords & 1)
                        lwords++;       /* pad it with 1 lword */
                txd_sizes[i].qwords = lwords >> 1;
                txd_sizes[i].bytes = lwords << 2;
        }
}

/* bdx_tx_init - initialize all Tx related stuff.
 * Namely, TXD and TXF fifos, database etc */
static int bdx_tx_init(struct bdx_priv *priv)
{
        if (bdx_fifo_init(priv, &priv->txd_fifo0.m, priv->txd_size,
                          regTXD_CFG0_0,
                          regTXD_CFG1_0, regTXD_RPTR_0, regTXD_WPTR_0))
                goto err_mem;
        if (bdx_fifo_init(priv, &priv->txf_fifo0.m, priv->txf_size,
                          regTXF_CFG0_0,
                          regTXF_CFG1_0, regTXF_RPTR_0, regTXF_WPTR_0))
                goto err_mem;

        /* The TX db has to keep mappings for all packets sent (on TxD)
         * and not yet reclaimed (on TxF) */
        if (bdx_tx_db_init(&priv->txdb, max(priv->txd_size, priv->txf_size)))
                goto err_mem;

        priv->tx_level = BDX_MAX_TX_LEVEL;
#ifdef BDX_DELAY_WPTR
        priv->tx_update_mark = priv->tx_level - 1024;
#endif
        return 0;

err_mem:
        netdev_err(priv->ndev, "Tx init failed\n");
        return -ENOMEM;
}

/**
 * bdx_tx_space - calculates available space in TX fifo
 * @priv: NIC private structure
 *
 * Returns available space in TX fifo in bytes
 */
static inline int bdx_tx_space(struct bdx_priv *priv)
{
        struct txd_fifo *f = &priv->txd_fifo0;
        int fsize;

        f->m.rptr = READ_REG(priv, f->m.reg_RPTR) & TXF_WPTR_WR_PTR;
        fsize = f->m.rptr - f->m.wptr;
        if (fsize <= 0)
                fsize = f->m.memsz + fsize;
        return fsize;
}

/**
 * bdx_tx_transmit - send packet to NIC
 * @skb: packet to send
 * @ndev: network device assigned to NIC
 * Return codes:
 * o NETDEV_TX_OK everything ok.
 * o NETDEV_TX_BUSY Cannot transmit packet, try later
 *   Usually a bug, means queue start/stop flow control is broken in
 *   the driver. Note: the driver must NOT put the skb in its DMA ring.
 */
static netdev_tx_t bdx_tx_transmit(struct sk_buff *skb,
                                   struct net_device *ndev)
{
        struct bdx_priv *priv = netdev_priv(ndev);
        struct txd_fifo *f = &priv->txd_fifo0;
        int txd_checksum = 7;   /* full checksum */
        int txd_lgsnd = 0;
        int txd_vlan_id = 0;
        int txd_vtag = 0;
        int txd_mss = 0;

        int nr_frags = skb_shinfo(skb)->nr_frags;
        struct txd_desc *txdd;
        int len;
        unsigned long flags;

        ENTER;
        local_irq_save(flags);
        spin_lock(&priv->tx_lock);

        /* build tx descriptor */
        BDX_ASSERT(f->m.wptr >= f->m.memsz);    /* started with valid wptr */
        txdd = (struct txd_desc *)(f->m.va + f->m.wptr);
        if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL))
                txd_checksum = 0;

        if (skb_shinfo(skb)->gso_size) {
                txd_mss = skb_shinfo(skb)->gso_size;
                txd_lgsnd = 1;
                DBG("skb %p skb len %d gso size = %d\n", skb, skb->len,
                    txd_mss);
        }

        if (skb_vlan_tag_present(skb)) {
                /*Cut VLAN ID to 12 bits */
                txd_vlan_id = skb_vlan_tag_get(skb) & BITS_MASK(12);
                txd_vtag = 1;
        }

        txdd->length = CPU_CHIP_SWAP16(skb->len);
        txdd->mss = CPU_CHIP_SWAP16(txd_mss);
        txdd->txd_val1 =
            CPU_CHIP_SWAP32(TXD_W1_VAL
                            (txd_sizes[nr_frags].qwords, txd_checksum, txd_vtag,
                             txd_lgsnd, txd_vlan_id));
        DBG("=== TxD desc =====================\n");
        DBG("=== w1: 0x%x ================\n", txdd->txd_val1);
        DBG("=== w2: mss 0x%x len 0x%x\n", txdd->mss, txdd->length);

        bdx_tx_map_skb(priv, skb, txdd);

        /* increment TXD write pointer. In case of
           fifo wrapping copy reminder of the descriptor
           to the beginning */
        f->m.wptr += txd_sizes[nr_frags].bytes;
        len = f->m.wptr - f->m.memsz;
        if (unlikely(len >= 0)) {
                f->m.wptr = len;
                if (len > 0) {
                        BDX_ASSERT(len > f->m.memsz);
                        memcpy(f->m.va, f->m.va + f->m.memsz, len);
                }
        }
        BDX_ASSERT(f->m.wptr >= f->m.memsz);    /* finished with valid wptr */

        priv->tx_level -= txd_sizes[nr_frags].bytes;
        BDX_ASSERT(priv->tx_level <= 0 || priv->tx_level > BDX_MAX_TX_LEVEL);
#ifdef BDX_DELAY_WPTR
        if (priv->tx_level > priv->tx_update_mark) {
                /* Force memory writes to complete before letting h/w
                   know there are new descriptors to fetch.
                   (might be needed on platforms like IA64)
                   wmb(); */
                WRITE_REG(priv, f->m.reg_WPTR, f->m.wptr & TXF_WPTR_WR_PTR);
        } else {
                if (priv->tx_noupd++ > BDX_NO_UPD_PACKETS) {
                        priv->tx_noupd = 0;
                        WRITE_REG(priv, f->m.reg_WPTR,
                                  f->m.wptr & TXF_WPTR_WR_PTR);
                }
        }
#else
        /* Force memory writes to complete before letting h/w
           know there are new descriptors to fetch.
           (might be needed on platforms like IA64)
           wmb(); */
        WRITE_REG(priv, f->m.reg_WPTR, f->m.wptr & TXF_WPTR_WR_PTR);

#endif
#ifdef BDX_LLTX
        netif_trans_update(ndev); /* NETIF_F_LLTX driver :( */
#endif
        ndev->stats.tx_packets++;
        ndev->stats.tx_bytes += skb->len;

        if (priv->tx_level < BDX_MIN_TX_LEVEL) {
                DBG("%s: %s: TX Q STOP level %d\n",
                    BDX_DRV_NAME, ndev->name, priv->tx_level);
                netif_stop_queue(ndev);
        }

        spin_unlock_irqrestore(&priv->tx_lock, flags);
        return NETDEV_TX_OK;
}

/**
 * bdx_tx_cleanup - clean TXF fifo, run in the context of IRQ.
 * @priv: bdx adapter
 *
 * It scans TXF fifo for descriptors, frees DMA mappings and reports to OS
 * that those packets were sent
 */
static void bdx_tx_cleanup(struct bdx_priv *priv)
{
        struct txf_fifo *f = &priv->txf_fifo0;
        struct txdb *db = &priv->txdb;
        int tx_level = 0;

        ENTER;
        f->m.wptr = READ_REG(priv, f->m.reg_WPTR) & TXF_WPTR_MASK;
        BDX_ASSERT(f->m.rptr >= f->m.memsz);    /* started with valid rptr */

        while (f->m.wptr != f->m.rptr) {
                f->m.rptr += BDX_TXF_DESC_SZ;
                f->m.rptr &= f->m.size_mask;

                /* unmap all the fragments */
                /* first has to come tx_maps containing dma */
                BDX_ASSERT(db->rptr->len == 0);
                do {
                        BDX_ASSERT(db->rptr->addr.dma == 0);
                        pci_unmap_page(priv->pdev, db->rptr->addr.dma,
                                       db->rptr->len, PCI_DMA_TODEVICE);
                        bdx_tx_db_inc_rptr(db);
                } while (db->rptr->len > 0);
                tx_level -= db->rptr->len;      /* '-' koz len is negative */

                /* now should come skb pointer - free it */
                dev_kfree_skb_irq(db->rptr->addr.skb);
                bdx_tx_db_inc_rptr(db);
        }

        /* let h/w know which TXF descriptors were cleaned */
        BDX_ASSERT((f->m.wptr & TXF_WPTR_WR_PTR) >= f->m.memsz);
        WRITE_REG(priv, f->m.reg_RPTR, f->m.rptr & TXF_WPTR_WR_PTR);

        /* We reclaimed resources, so in case the Q is stopped by xmit callback,
         * we resume the transmission and use tx_lock to synchronize with xmit.*/
        spin_lock(&priv->tx_lock);
        priv->tx_level += tx_level;
        BDX_ASSERT(priv->tx_level <= 0 || priv->tx_level > BDX_MAX_TX_LEVEL);
#ifdef BDX_DELAY_WPTR
        if (priv->tx_noupd) {
                priv->tx_noupd = 0;
                WRITE_REG(priv, priv->txd_fifo0.m.reg_WPTR,
                          priv->txd_fifo0.m.wptr & TXF_WPTR_WR_PTR);
        }
#endif

        if (unlikely(netif_queue_stopped(priv->ndev) &&
                     netif_carrier_ok(priv->ndev) &&
                     (priv->tx_level >= BDX_MIN_TX_LEVEL))) {
                DBG("%s: %s: TX Q WAKE level %d\n",
                    BDX_DRV_NAME, priv->ndev->name, priv->tx_level);
                netif_wake_queue(priv->ndev);
        }
        spin_unlock(&priv->tx_lock);
}

/**
 * bdx_tx_free_skbs - frees all skbs from TXD fifo.
 * It gets called when OS stops this dev, eg upon "ifconfig down" or rmmod
 */
static void bdx_tx_free_skbs(struct bdx_priv *priv)
{
        struct txdb *db = &priv->txdb;

        ENTER;
        while (db->rptr != db->wptr) {
                if (likely(db->rptr->len))
                        pci_unmap_page(priv->pdev, db->rptr->addr.dma,
                                       db->rptr->len, PCI_DMA_TODEVICE);
                else
                        dev_kfree_skb(db->rptr->addr.skb);
                bdx_tx_db_inc_rptr(db);
        }
        RET();
}

/* bdx_tx_free - frees all Tx resources */
static void bdx_tx_free(struct bdx_priv *priv)
{
        ENTER;
        bdx_tx_free_skbs(priv);
        bdx_fifo_free(priv, &priv->txd_fifo0.m);
        bdx_fifo_free(priv, &priv->txf_fifo0.m);
        bdx_tx_db_close(&priv->txdb);
}

/**
 * bdx_tx_push_desc - push descriptor to TxD fifo
 * @priv: NIC private structure
 * @data: desc's data
 * @size: desc's size
 *
 * Pushes desc to TxD fifo and overlaps it if needed.
 * NOTE: this func does not check for available space. this is responsibility
 *    of the caller. Neither does it check that data size is smaller than
 *    fifo size.
 */
static void bdx_tx_push_desc(struct bdx_priv *priv, void *data, int size)
{
        struct txd_fifo *f = &priv->txd_fifo0;
        int i = f->m.memsz - f->m.wptr;

        if (size == 0)
                return;

        if (i > size) {
                memcpy(f->m.va + f->m.wptr, data, size);
                f->m.wptr += size;
        } else {
                memcpy(f->m.va + f->m.wptr, data, i);
                f->m.wptr = size - i;
                memcpy(f->m.va, data + i, f->m.wptr);
        }
        WRITE_REG(priv, f->m.reg_WPTR, f->m.wptr & TXF_WPTR_WR_PTR);
}

/**
 * bdx_tx_push_desc_safe - push descriptor to TxD fifo in a safe way
 * @priv: NIC private structure
 * @data: desc's data
 * @size: desc's size
 *
 * NOTE: this func does check for available space and, if necessary, waits for
 *   NIC to read existing data before writing new one.
 */
static void bdx_tx_push_desc_safe(struct bdx_priv *priv, void *data, int size)
{
        int timer = 0;
        ENTER;

        while (size > 0) {
                /* we substruct 8 because when fifo is full rptr == wptr
                   which also means that fifo is empty, we can understand
                   the difference, but could hw do the same ??? :) */
                int avail = bdx_tx_space(priv) - 8;
                if (avail <= 0) {
                        if (timer++ > 300) {    /* prevent endless loop */
                                DBG("timeout while writing desc to TxD fifo\n");
                                break;
                        }
                        udelay(50);     /* give hw a chance to clean fifo */
                        continue;
                }
                avail = min(avail, size);
                DBG("about to push  %d bytes starting %p size %d\n", avail,
                    data, size);
                bdx_tx_push_desc(priv, data, avail);
                size -= avail;
                data += avail;
        }
        RET();
}

static const struct net_device_ops bdx_netdev_ops = {
        .ndo_open               = bdx_open,
        .ndo_stop               = bdx_close,
        .ndo_start_xmit         = bdx_tx_transmit,
        .ndo_validate_addr      = eth_validate_addr,
        .ndo_do_ioctl           = bdx_ioctl,
        .ndo_set_rx_mode        = bdx_setmulti,
        .ndo_change_mtu         = bdx_change_mtu,
        .ndo_set_mac_address    = bdx_set_mac,
        .ndo_vlan_rx_add_vid    = bdx_vlan_rx_add_vid,
        .ndo_vlan_rx_kill_vid   = bdx_vlan_rx_kill_vid,
};

/**
 * bdx_probe - Device Initialization Routine
 * @pdev: PCI device information struct
 * @ent: entry in bdx_pci_tbl
 *
 * Returns 0 on success, negative on failure
 *
 * bdx_probe initializes an adapter identified by a pci_dev structure.
 * The OS initialization, configuring of the adapter private structure,
 * and a hardware reset occur.
 *
 * functions and their order used as explained in
 * /usr/src/linux/Documentation/DMA-{API,mapping}.txt
 *
 */

/* TBD: netif_msg should be checked and implemented. I disable it for now */
static int
bdx_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
{
        struct net_device *ndev;
        struct bdx_priv *priv;
        int err, pci_using_dac, port;
        unsigned long pciaddr;
        u32 regionSize;
        struct pci_nic *nic;

        ENTER;

        nic = vmalloc(sizeof(*nic));
        if (!nic)
                RET(-ENOMEM);

    /************** pci *****************/
        err = pci_enable_device(pdev);
        if (err)                        /* it triggers interrupt, dunno why. */
                goto err_pci;           /* it's not a problem though */

        if (!(err = pci_set_dma_mask(pdev, DMA_BIT_MASK(64))) &&
            !(err = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(64)))) {
                pci_using_dac = 1;
        } else {
                if ((err = pci_set_dma_mask(pdev, DMA_BIT_MASK(32))) ||
                    (err = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32)))) {
                        pr_err("No usable DMA configuration, aborting\n");
                        goto err_dma;
                }
                pci_using_dac = 0;
        }

        err = pci_request_regions(pdev, BDX_DRV_NAME);
        if (err)
                goto err_dma;

        pci_set_master(pdev);

        pciaddr = pci_resource_start(pdev, 0);
        if (!pciaddr) {
                err = -EIO;
                pr_err("no MMIO resource\n");
                goto err_out_res;
        }
        regionSize = pci_resource_len(pdev, 0);
        if (regionSize < BDX_REGS_SIZE) {
                err = -EIO;
                pr_err("MMIO resource (%x) too small\n", regionSize);
                goto err_out_res;
        }

        nic->regs = ioremap(pciaddr, regionSize);
        if (!nic->regs) {
                err = -EIO;
                pr_err("ioremap failed\n");
                goto err_out_res;
        }

        if (pdev->irq < 2) {
                err = -EIO;
                pr_err("invalid irq (%d)\n", pdev->irq);
                goto err_out_iomap;
        }
        pci_set_drvdata(pdev, nic);

        if (pdev->device == 0x3014)
                nic->port_num = 2;
        else
                nic->port_num = 1;

        print_hw_id(pdev);

        bdx_hw_reset_direct(nic->regs);

        nic->irq_type = IRQ_INTX;
#ifdef BDX_MSI
        if ((readl(nic->regs + FPGA_VER) & 0xFFF) >= 378) {
                err = pci_enable_msi(pdev);
                if (err)
                        pr_err("Can't enable msi. error is %d\n", err);
                else
                        nic->irq_type = IRQ_MSI;
        } else
                DBG("HW does not support MSI\n");
#endif

    /************** netdev **************/
        for (port = 0; port < nic->port_num; port++) {
                ndev = alloc_etherdev(sizeof(struct bdx_priv));
                if (!ndev) {
                        err = -ENOMEM;
                        goto err_out_iomap;
                }

                ndev->netdev_ops = &bdx_netdev_ops;
                ndev->tx_queue_len = BDX_NDEV_TXQ_LEN;

                bdx_set_ethtool_ops(ndev);      /* ethtool interface */

                /* these fields are used for info purposes only

                 * so we can have them same for all ports of the board */
                ndev->if_port = port;
                ndev->features = NETIF_F_IP_CSUM | NETIF_F_SG | NETIF_F_TSO
                    | NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX |
                    NETIF_F_HW_VLAN_CTAG_FILTER | NETIF_F_RXCSUM
                    ;
                ndev->hw_features = NETIF_F_IP_CSUM | NETIF_F_SG |
                        NETIF_F_TSO | NETIF_F_HW_VLAN_CTAG_TX;

                if (pci_using_dac)
                        ndev->features |= NETIF_F_HIGHDMA;

        /************** priv ****************/
                priv = nic->priv[port] = netdev_priv(ndev);

                priv->pBdxRegs = nic->regs + port * 0x8000;
                priv->port = port;
                priv->pdev = pdev;
                priv->ndev = ndev;
                priv->nic = nic;
                priv->msg_enable = BDX_DEF_MSG_ENABLE;

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

                if ((readl(nic->regs + FPGA_VER) & 0xFFF) == 308) {
                        DBG("HW statistics not supported\n");
                        priv->stats_flag = 0;
                } else {
                        priv->stats_flag = 1;
                }

                /* Initialize fifo sizes. */
                priv->txd_size = 2;
                priv->txf_size = 2;
                priv->rxd_size = 2;
                priv->rxf_size = 3;

                /* Initialize the initial coalescing registers. */
                priv->rdintcm = INT_REG_VAL(0x20, 1, 4, 12);
                priv->tdintcm = INT_REG_VAL(0x20, 1, 0, 12);

                /* ndev->xmit_lock spinlock is not used.
                 * Private priv->tx_lock is used for synchronization
                 * between transmit and TX irq cleanup.  In addition
                 * set multicast list callback has to use priv->tx_lock.
                 */
#ifdef BDX_LLTX
                ndev->features |= NETIF_F_LLTX;
#endif
                /* MTU range: 60 - 16384 */
                ndev->min_mtu = ETH_ZLEN;
                ndev->max_mtu = BDX_MAX_MTU;

                spin_lock_init(&priv->tx_lock);

                /*bdx_hw_reset(priv); */
                if (bdx_read_mac(priv)) {
                        pr_err("load MAC address failed\n");
                        goto err_out_iomap;
                }
                SET_NETDEV_DEV(ndev, &pdev->dev);
                err = register_netdev(ndev);
                if (err) {
                        pr_err("register_netdev failed\n");
                        goto err_out_free;
                }
                netif_carrier_off(ndev);
                netif_stop_queue(ndev);

                print_eth_id(ndev);
        }
        RET(0);

err_out_free:
        free_netdev(ndev);
err_out_iomap:
        iounmap(nic->regs);
err_out_res:
        pci_release_regions(pdev);
err_dma:
        pci_disable_device(pdev);
err_pci:
        vfree(nic);

        RET(err);
}

/****************** Ethtool interface *********************/
/* get strings for statistics counters */
static const char
 bdx_stat_names[][ETH_GSTRING_LEN] = {
        "InUCast",              /* 0x7200 */
        "InMCast",              /* 0x7210 */
        "InBCast",              /* 0x7220 */
        "InPkts",               /* 0x7230 */
        "InErrors",             /* 0x7240 */
        "InDropped",            /* 0x7250 */
        "FrameTooLong",         /* 0x7260 */
        "FrameSequenceErrors",  /* 0x7270 */
        "InVLAN",               /* 0x7280 */
        "InDroppedDFE",         /* 0x7290 */
        "InDroppedIntFull",     /* 0x72A0 */
        "InFrameAlignErrors",   /* 0x72B0 */

        /* 0x72C0-0x72E0 RSRV */

        "OutUCast",             /* 0x72F0 */
        "OutMCast",             /* 0x7300 */
        "OutBCast",             /* 0x7310 */
        "OutPkts",              /* 0x7320 */

        /* 0x7330-0x7360 RSRV */

        "OutVLAN",              /* 0x7370 */
        "InUCastOctects",       /* 0x7380 */
        "OutUCastOctects",      /* 0x7390 */

        /* 0x73A0-0x73B0 RSRV */

        "InBCastOctects",       /* 0x73C0 */
        "OutBCastOctects",      /* 0x73D0 */
        "InOctects",            /* 0x73E0 */
        "OutOctects",           /* 0x73F0 */
};

/*
 * bdx_get_settings - get device-specific settings
 * @netdev
 * @ecmd
 */
static int bdx_get_settings(struct net_device *netdev, struct ethtool_cmd *ecmd)
{
        u32 rdintcm;
        u32 tdintcm;
        struct bdx_priv *priv = netdev_priv(netdev);

        rdintcm = priv->rdintcm;
        tdintcm = priv->tdintcm;

        ecmd->supported = (SUPPORTED_10000baseT_Full | SUPPORTED_FIBRE);
        ecmd->advertising = (ADVERTISED_10000baseT_Full | ADVERTISED_FIBRE);
        ethtool_cmd_speed_set(ecmd, SPEED_10000);
        ecmd->duplex = DUPLEX_FULL;
        ecmd->port = PORT_FIBRE;
        ecmd->transceiver = XCVR_EXTERNAL;      /* what does it mean? */
        ecmd->autoneg = AUTONEG_DISABLE;

        /* PCK_TH measures in multiples of FIFO bytes
           We translate to packets */
        ecmd->maxtxpkt =
            ((GET_PCK_TH(tdintcm) * PCK_TH_MULT) / BDX_TXF_DESC_SZ);
        ecmd->maxrxpkt =
            ((GET_PCK_TH(rdintcm) * PCK_TH_MULT) / sizeof(struct rxf_desc));

        return 0;
}

/*
 * bdx_get_drvinfo - report driver information
 * @netdev
 * @drvinfo
 */
static void
bdx_get_drvinfo(struct net_device *netdev, struct ethtool_drvinfo *drvinfo)
{
        struct bdx_priv *priv = netdev_priv(netdev);

        strlcpy(drvinfo->driver, BDX_DRV_NAME, sizeof(drvinfo->driver));
        strlcpy(drvinfo->version, BDX_DRV_VERSION, sizeof(drvinfo->version));
        strlcpy(drvinfo->fw_version, "N/A", sizeof(drvinfo->fw_version));
        strlcpy(drvinfo->bus_info, pci_name(priv->pdev),
                sizeof(drvinfo->bus_info));
}

/*
 * bdx_get_coalesce - get interrupt coalescing parameters
 * @netdev
 * @ecoal
 */
static int
bdx_get_coalesce(struct net_device *netdev, struct ethtool_coalesce *ecoal)
{
        u32 rdintcm;
        u32 tdintcm;
        struct bdx_priv *priv = netdev_priv(netdev);

        rdintcm = priv->rdintcm;
        tdintcm = priv->tdintcm;

        /* PCK_TH measures in multiples of FIFO bytes
           We translate to packets */
        ecoal->rx_coalesce_usecs = GET_INT_COAL(rdintcm) * INT_COAL_MULT;
        ecoal->rx_max_coalesced_frames =
            ((GET_PCK_TH(rdintcm) * PCK_TH_MULT) / sizeof(struct rxf_desc));

        ecoal->tx_coalesce_usecs = GET_INT_COAL(tdintcm) * INT_COAL_MULT;
        ecoal->tx_max_coalesced_frames =
            ((GET_PCK_TH(tdintcm) * PCK_TH_MULT) / BDX_TXF_DESC_SZ);

        /* adaptive parameters ignored */
        return 0;
}

/*
 * bdx_set_coalesce - set interrupt coalescing parameters
 * @netdev
 * @ecoal
 */
static int
bdx_set_coalesce(struct net_device *netdev, struct ethtool_coalesce *ecoal)
{
        u32 rdintcm;
        u32 tdintcm;
        struct bdx_priv *priv = netdev_priv(netdev);
        int rx_coal;
        int tx_coal;
        int rx_max_coal;
        int tx_max_coal;

        /* Check for valid input */
        rx_coal = ecoal->rx_coalesce_usecs / INT_COAL_MULT;
        tx_coal = ecoal->tx_coalesce_usecs / INT_COAL_MULT;
        rx_max_coal = ecoal->rx_max_coalesced_frames;
        tx_max_coal = ecoal->tx_max_coalesced_frames;

        /* Translate from packets to multiples of FIFO bytes */
        rx_max_coal =
            (((rx_max_coal * sizeof(struct rxf_desc)) + PCK_TH_MULT - 1)
             / PCK_TH_MULT);
        tx_max_coal =
            (((tx_max_coal * BDX_TXF_DESC_SZ) + PCK_TH_MULT - 1)
             / PCK_TH_MULT);

        if ((rx_coal > 0x7FFF) || (tx_coal > 0x7FFF) ||
            (rx_max_coal > 0xF) || (tx_max_coal > 0xF))
                return -EINVAL;

        rdintcm = INT_REG_VAL(rx_coal, GET_INT_COAL_RC(priv->rdintcm),
                              GET_RXF_TH(priv->rdintcm), rx_max_coal);
        tdintcm = INT_REG_VAL(tx_coal, GET_INT_COAL_RC(priv->tdintcm), 0,
                              tx_max_coal);

        priv->rdintcm = rdintcm;
        priv->tdintcm = tdintcm;

        WRITE_REG(priv, regRDINTCM0, rdintcm);
        WRITE_REG(priv, regTDINTCM0, tdintcm);

        return 0;
}

/* Convert RX fifo size to number of pending packets */
static inline int bdx_rx_fifo_size_to_packets(int rx_size)
{
        return (FIFO_SIZE * (1 << rx_size)) / sizeof(struct rxf_desc);
}

/* Convert TX fifo size to number of pending packets */
static inline int bdx_tx_fifo_size_to_packets(int tx_size)
{
        return (FIFO_SIZE * (1 << tx_size)) / BDX_TXF_DESC_SZ;
}

/*
 * bdx_get_ringparam - report ring sizes
 * @netdev
 * @ring
 */
static void
bdx_get_ringparam(struct net_device *netdev, struct ethtool_ringparam *ring)
{
        struct bdx_priv *priv = netdev_priv(netdev);

        /*max_pending - the maximum-sized FIFO we allow */
        ring->rx_max_pending = bdx_rx_fifo_size_to_packets(3);
        ring->tx_max_pending = bdx_tx_fifo_size_to_packets(3);
        ring->rx_pending = bdx_rx_fifo_size_to_packets(priv->rxf_size);
        ring->tx_pending = bdx_tx_fifo_size_to_packets(priv->txd_size);
}

/*
 * bdx_set_ringparam - set ring sizes
 * @netdev
 * @ring
 */
static int
bdx_set_ringparam(struct net_device *netdev, struct ethtool_ringparam *ring)
{
        struct bdx_priv *priv = netdev_priv(netdev);
        int rx_size = 0;
        int tx_size = 0;

        for (; rx_size < 4; rx_size++) {
                if (bdx_rx_fifo_size_to_packets(rx_size) >= ring->rx_pending)
                        break;
        }
        if (rx_size == 4)
                rx_size = 3;

        for (; tx_size < 4; tx_size++) {
                if (bdx_tx_fifo_size_to_packets(tx_size) >= ring->tx_pending)
                        break;
        }
        if (tx_size == 4)
                tx_size = 3;

        /*Is there anything to do? */
        if ((rx_size == priv->rxf_size) &&
            (tx_size == priv->txd_size))
                return 0;

        priv->rxf_size = rx_size;
        if (rx_size > 1)
                priv->rxd_size = rx_size - 1;
        else
                priv->rxd_size = rx_size;

        priv->txf_size = priv->txd_size = tx_size;

        if (netif_running(netdev)) {
                bdx_close(netdev);
                bdx_open(netdev);
        }
        return 0;
}

/*
 * bdx_get_strings - return a set of strings that describe the requested objects
 * @netdev
 * @data
 */
static void bdx_get_strings(struct net_device *netdev, u32 stringset, u8 *data)
{
        switch (stringset) {
        case ETH_SS_STATS:
                memcpy(data, *bdx_stat_names, sizeof(bdx_stat_names));
                break;
        }
}

/*
 * bdx_get_sset_count - return number of statistics or tests
 * @netdev
 */
static int bdx_get_sset_count(struct net_device *netdev, int stringset)
{
        struct bdx_priv *priv = netdev_priv(netdev);

        switch (stringset) {
        case ETH_SS_STATS:
                BDX_ASSERT(ARRAY_SIZE(bdx_stat_names)
                           != sizeof(struct bdx_stats) / sizeof(u64));
                return (priv->stats_flag) ? ARRAY_SIZE(bdx_stat_names)  : 0;
        }

        return -EINVAL;
}

/*
 * bdx_get_ethtool_stats - return device's hardware L2 statistics
 * @netdev
 * @stats
 * @data
 */
static void bdx_get_ethtool_stats(struct net_device *netdev,
                                  struct ethtool_stats *stats, u64 *data)
{
        struct bdx_priv *priv = netdev_priv(netdev);

        if (priv->stats_flag) {

                /* Update stats from HW */
                bdx_update_stats(priv);

                /* Copy data to user buffer */
                memcpy(data, &priv->hw_stats, sizeof(priv->hw_stats));
        }
}

/*
 * bdx_set_ethtool_ops - ethtool interface implementation
 * @netdev
 */
static void bdx_set_ethtool_ops(struct net_device *netdev)
{
        static const struct ethtool_ops bdx_ethtool_ops = {
                .get_settings = bdx_get_settings,
                .get_drvinfo = bdx_get_drvinfo,
                .get_link = ethtool_op_get_link,
                .get_coalesce = bdx_get_coalesce,
                .set_coalesce = bdx_set_coalesce,
                .get_ringparam = bdx_get_ringparam,
                .set_ringparam = bdx_set_ringparam,
                .get_strings = bdx_get_strings,
                .get_sset_count = bdx_get_sset_count,
                .get_ethtool_stats = bdx_get_ethtool_stats,
        };

        netdev->ethtool_ops = &bdx_ethtool_ops;
}

/**
 * bdx_remove - Device Removal Routine
 * @pdev: PCI device information struct
 *
 * bdx_remove is called by the PCI subsystem to alert the driver
 * that it should release a PCI device.  The could be caused by a
 * Hot-Plug event, or because the driver is going to be removed from
 * memory.
 **/
static void bdx_remove(struct pci_dev *pdev)
{
        struct pci_nic *nic = pci_get_drvdata(pdev);
        struct net_device *ndev;
        int port;

        for (port = 0; port < nic->port_num; port++) {
                ndev = nic->priv[port]->ndev;
                unregister_netdev(ndev);
                free_netdev(ndev);
        }

        /*bdx_hw_reset_direct(nic->regs); */
#ifdef BDX_MSI
        if (nic->irq_type == IRQ_MSI)
                pci_disable_msi(pdev);
#endif

        iounmap(nic->regs);
        pci_release_regions(pdev);
        pci_disable_device(pdev);
        vfree(nic);

        RET();
}

static struct pci_driver bdx_pci_driver = {
        .name = BDX_DRV_NAME,
        .id_table = bdx_pci_tbl,
        .probe = bdx_probe,
        .remove = bdx_remove,
};

/*
 * print_driver_id - print parameters of the driver build
 */
static void __init print_driver_id(void)
{
        pr_info("%s, %s\n", BDX_DRV_DESC, BDX_DRV_VERSION);
        pr_info("Options: hw_csum %s\n", BDX_MSI_STRING);
}

static int __init bdx_module_init(void)
{
        ENTER;
        init_txd_sizes();
        print_driver_id();
        RET(pci_register_driver(&bdx_pci_driver));
}

module_init(bdx_module_init);

static void __exit bdx_module_exit(void)
{
        ENTER;
        pci_unregister_driver(&bdx_pci_driver);
        RET();
}

module_exit(bdx_module_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(BDX_DRV_DESC);
MODULE_FIRMWARE("tehuti/bdx.bin");