/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2012
 *      Ben Gray <bgray@freebsd.org>.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Microchip LAN9xxx devices (https://www.microchip.com/en-us/product/lan9500a)
 * 
 * The LAN9500 & LAN9500A devices are stand-alone USB to Ethernet chips that
 * support USB 2.0 and 10/100 Mbps Ethernet.
 *
 * The LAN951x devices are an integrated USB hub and USB to Ethernet adapter.
 * The driver only covers the Ethernet part, the standard USB hub driver
 * supports the hub part.
 *
 * This driver is closely modelled on the Linux driver written and copyrighted
 * by SMSC (later acquired by Microchip).
 *
 *
 *
 *
 * H/W TCP & UDP Checksum Offloading
 * ---------------------------------
 * The chip supports both tx and rx offloading of UDP & TCP checksums, this
 * feature can be dynamically enabled/disabled.  
 *
 * RX checksuming is performed across bytes after the IPv4 header to the end of
 * the Ethernet frame, this means if the frame is padded with non-zero values
 * the H/W checksum will be incorrect, however the rx code compensates for this.
 *
 * TX checksuming is more complicated, the device requires a special header to
 * be prefixed onto the start of the frame which indicates the start and end
 * positions of the UDP or TCP frame.  This requires the driver to manually
 * go through the packet data and decode the headers prior to sending.
 * On Linux they generally provide cues to the location of the csum and the
 * area to calculate it over, on FreeBSD we seem to have to do it all ourselves,
 * hence this is not as optimal and therefore h/w tX checksum is currently not
 * implemented.
 *
 */
#include <sys/stdint.h>
#include <sys/stddef.h>
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/types.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/condvar.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/sx.h>
#include <sys/unistd.h>
#include <sys/callout.h>
#include <sys/malloc.h>
#include <sys/priv.h>
#include <sys/random.h>

#include <net/if.h>
#include <net/if_var.h>
#include <net/if_media.h>

#include <dev/mii/mii.h>
#include <dev/mii/miivar.h>

#include <netinet/in.h>
#include <netinet/ip.h>

#include "opt_platform.h"

#ifdef FDT
#include <dev/fdt/fdt_common.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <dev/usb/usb_fdt_support.h>
#endif

#include <dev/usb/usb.h>
#include <dev/usb/usbdi.h>
#include <dev/usb/usbdi_util.h>
#include "usbdevs.h"

#define USB_DEBUG_VAR smsc_debug
#include <dev/usb/usb_debug.h>
#include <dev/usb/usb_process.h>

#include <dev/usb/net/usb_ethernet.h>

#include <dev/usb/net/if_smscreg.h>

#include "miibus_if.h"

SYSCTL_NODE(_hw_usb, OID_AUTO, smsc, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "USB smsc");

static bool smsc_rx_packet_batching = 1;

SYSCTL_BOOL(_hw_usb_smsc, OID_AUTO, smsc_rx_packet_batching, CTLFLAG_RDTUN,
    &smsc_rx_packet_batching, 0,
    "If set, allows packet batching to increase throughput and latency. "
    "Else throughput and latency is decreased.");

#ifdef USB_DEBUG
static int smsc_debug = 0;

SYSCTL_INT(_hw_usb_smsc, OID_AUTO, debug, CTLFLAG_RWTUN, &smsc_debug, 0,
    "Debug level");
#endif

/*
 * Various supported device vendors/products.
 */
static const struct usb_device_id smsc_devs[] = {
#define SMSC_DEV(p,i) { USB_VPI(USB_VENDOR_SMC2, USB_PRODUCT_SMC2_##p, i) }
        SMSC_DEV(LAN89530_ETH, 0),
        SMSC_DEV(LAN9500_ETH, 0),
        SMSC_DEV(LAN9500_ETH_2, 0),
        SMSC_DEV(LAN9500A_ETH, 0),
        SMSC_DEV(LAN9500A_ETH_2, 0),
        SMSC_DEV(LAN9505_ETH, 0),
        SMSC_DEV(LAN9505A_ETH, 0),
        SMSC_DEV(LAN9514_ETH, 0),
        SMSC_DEV(LAN9514_ETH_2, 0),
        SMSC_DEV(LAN9530_ETH, 0),
        SMSC_DEV(LAN9730_ETH, 0),
        SMSC_DEV(LAN9500_SAL10, 0),
        SMSC_DEV(LAN9505_SAL10, 0),
        SMSC_DEV(LAN9500A_SAL10, 0),
        SMSC_DEV(LAN9505A_SAL10, 0),
        SMSC_DEV(LAN9514_SAL10, 0),
        SMSC_DEV(LAN9500A_HAL, 0),
        SMSC_DEV(LAN9505A_HAL, 0),
#undef SMSC_DEV
};

#ifdef USB_DEBUG
#define smsc_dbg_printf(sc, fmt, args...) \
        do { \
                if (smsc_debug > 0) \
                        device_printf((sc)->sc_ue.ue_dev, "debug: " fmt, ##args); \
        } while(0)
#else
#define smsc_dbg_printf(sc, fmt, args...) do { } while (0)
#endif

#define smsc_warn_printf(sc, fmt, args...) \
        device_printf((sc)->sc_ue.ue_dev, "warning: " fmt, ##args)

#define smsc_err_printf(sc, fmt, args...) \
        device_printf((sc)->sc_ue.ue_dev, "error: " fmt, ##args)

#define ETHER_IS_VALID(addr) \
        (!ETHER_IS_MULTICAST(addr) && !ETHER_IS_ZERO(addr))

#define BOOTARGS_SMSC95XX       "smsc95xx.macaddr"

static device_probe_t smsc_probe;
static device_attach_t smsc_attach;
static device_detach_t smsc_detach;

static usb_callback_t smsc_bulk_read_callback;
static usb_callback_t smsc_bulk_write_callback;

static miibus_readreg_t smsc_miibus_readreg;
static miibus_writereg_t smsc_miibus_writereg;
static miibus_statchg_t smsc_miibus_statchg;

static int smsc_attach_post_sub(struct usb_ether *ue);
static uether_fn_t smsc_attach_post;
static uether_fn_t smsc_init;
static uether_fn_t smsc_stop;
static uether_fn_t smsc_start;
static uether_fn_t smsc_tick;
static uether_fn_t smsc_setmulti;
static uether_fn_t smsc_setpromisc;

static int      smsc_ifmedia_upd(if_t);
static void     smsc_ifmedia_sts(if_t, struct ifmediareq *);

static int smsc_chip_init(struct smsc_softc *sc);
static int smsc_ioctl(if_t ifp, u_long cmd, caddr_t data);

static const struct usb_config smsc_config[SMSC_N_TRANSFER] = {
        [SMSC_BULK_DT_WR] = {
                .type = UE_BULK,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_OUT,
                .frames = 16,
                .bufsize = 16 * (MCLBYTES + 16),
                .flags = {.pipe_bof = 1,.force_short_xfer = 1,},
                .callback = smsc_bulk_write_callback,
                .timeout = 10000,       /* 10 seconds */
        },

        [SMSC_BULK_DT_RD] = {
                .type = UE_BULK,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_IN,
                .bufsize = 20480,       /* bytes */
                .flags = {.pipe_bof = 1,.short_xfer_ok = 1,},
                .callback = smsc_bulk_read_callback,
                .timeout = 0,   /* no timeout */
        },

        /* The SMSC chip supports an interrupt endpoints, however they aren't
         * needed as we poll on the MII status.
         */
};

static const struct usb_ether_methods smsc_ue_methods = {
        .ue_attach_post = smsc_attach_post,
        .ue_attach_post_sub = smsc_attach_post_sub,
        .ue_start = smsc_start,
        .ue_ioctl = smsc_ioctl,
        .ue_init = smsc_init,
        .ue_stop = smsc_stop,
        .ue_tick = smsc_tick,
        .ue_setmulti = smsc_setmulti,
        .ue_setpromisc = smsc_setpromisc,
        .ue_mii_upd = smsc_ifmedia_upd,
        .ue_mii_sts = smsc_ifmedia_sts,
};

/**
 *      smsc_read_reg - Reads a 32-bit register on the device
 *      @sc: driver soft context
 *      @off: offset of the register
 *      @data: pointer a value that will be populated with the register value
 *      
 *      LOCKING:
 *      The device lock must be held before calling this function.
 *
 *      RETURNS:
 *      0 on success, a USB_ERR_?? error code on failure.
 */
static int
smsc_read_reg(struct smsc_softc *sc, uint32_t off, uint32_t *data)
{
        struct usb_device_request req;
        uint32_t buf;
        usb_error_t err;

        SMSC_LOCK_ASSERT(sc, MA_OWNED);

        req.bmRequestType = UT_READ_VENDOR_DEVICE;
        req.bRequest = SMSC_UR_READ_REG;
        USETW(req.wValue, 0);
        USETW(req.wIndex, off);
        USETW(req.wLength, 4);

        err = uether_do_request(&sc->sc_ue, &req, &buf, 1000);
        if (err != 0)
                smsc_warn_printf(sc, "Failed to read register 0x%0x\n", off);

        *data = le32toh(buf);

        return (err);
}

/**
 *      smsc_write_reg - Writes a 32-bit register on the device
 *      @sc: driver soft context
 *      @off: offset of the register
 *      @data: the 32-bit value to write into the register
 *      
 *      LOCKING:
 *      The device lock must be held before calling this function.
 *
 *      RETURNS:
 *      0 on success, a USB_ERR_?? error code on failure.
 */
static int
smsc_write_reg(struct smsc_softc *sc, uint32_t off, uint32_t data)
{
        struct usb_device_request req;
        uint32_t buf;
        usb_error_t err;

        SMSC_LOCK_ASSERT(sc, MA_OWNED);

        buf = htole32(data);

        req.bmRequestType = UT_WRITE_VENDOR_DEVICE;
        req.bRequest = SMSC_UR_WRITE_REG;
        USETW(req.wValue, 0);
        USETW(req.wIndex, off);
        USETW(req.wLength, 4);

        err = uether_do_request(&sc->sc_ue, &req, &buf, 1000);
        if (err != 0)
                smsc_warn_printf(sc, "Failed to write register 0x%0x\n", off);

        return (err);
}

/**
 *      smsc_wait_for_bits - Polls on a register value until bits are cleared
 *      @sc: soft context
 *      @reg: offset of the register
 *      @bits: if the bits are clear the function returns
 *
 *      LOCKING:
 *      The device lock must be held before calling this function.
 *
 *      RETURNS:
 *      0 on success, or a USB_ERR_?? error code on failure.
 */
static int
smsc_wait_for_bits(struct smsc_softc *sc, uint32_t reg, uint32_t bits)
{
        usb_ticks_t start_ticks;
        const usb_ticks_t max_ticks = USB_MS_TO_TICKS(1000);
        uint32_t val;
        int err;

        SMSC_LOCK_ASSERT(sc, MA_OWNED);

        start_ticks = (usb_ticks_t)ticks;
        do {
                if ((err = smsc_read_reg(sc, reg, &val)) != 0)
                        return (err);
                if (!(val & bits))
                        return (0);
                
                uether_pause(&sc->sc_ue, hz / 100);
        } while (((usb_ticks_t)(ticks - start_ticks)) < max_ticks);

        return (USB_ERR_TIMEOUT);
}

/**
 *      smsc_eeprom_read - Reads the attached EEPROM
 *      @sc: soft context
 *      @off: the eeprom address offset
 *      @buf: stores the bytes
 *      @buflen: the number of bytes to read
 *
 *      Simply reads bytes from an attached eeprom.
 *
 *      LOCKING:
 *      The function takes and releases the device lock if it is not already held.
 *
 *      RETURNS:
 *      0 on success, or a USB_ERR_?? error code on failure.
 */
static int
smsc_eeprom_read(struct smsc_softc *sc, uint16_t off, uint8_t *buf, uint16_t buflen)
{
        usb_ticks_t start_ticks;
        const usb_ticks_t max_ticks = USB_MS_TO_TICKS(1000);
        int err;
        int locked;
        uint32_t val;
        uint16_t i;

        locked = mtx_owned(&sc->sc_mtx);
        if (!locked)
                SMSC_LOCK(sc);

        err = smsc_wait_for_bits(sc, SMSC_EEPROM_CMD, SMSC_EEPROM_CMD_BUSY);
        if (err != 0) {
                smsc_warn_printf(sc, "eeprom busy, failed to read data\n");
                goto done;
        }

        /* start reading the bytes, one at a time */
        for (i = 0; i < buflen; i++) {
                val = SMSC_EEPROM_CMD_BUSY | (SMSC_EEPROM_CMD_ADDR_MASK & (off + i));
                if ((err = smsc_write_reg(sc, SMSC_EEPROM_CMD, val)) != 0)
                        goto done;
                
                start_ticks = (usb_ticks_t)ticks;
                do {
                        if ((err = smsc_read_reg(sc, SMSC_EEPROM_CMD, &val)) != 0)
                                goto done;
                        if (!(val & SMSC_EEPROM_CMD_BUSY) || (val & SMSC_EEPROM_CMD_TIMEOUT))
                                break;

                        uether_pause(&sc->sc_ue, hz / 100);
                } while (((usb_ticks_t)(ticks - start_ticks)) < max_ticks);

                if (val & (SMSC_EEPROM_CMD_BUSY | SMSC_EEPROM_CMD_TIMEOUT)) {
                        smsc_warn_printf(sc, "eeprom command failed\n");
                        err = USB_ERR_IOERROR;
                        break;
                }
                        
                if ((err = smsc_read_reg(sc, SMSC_EEPROM_DATA, &val)) != 0)
                        goto done;

                buf[i] = (val & 0xff);
        }

done:
        if (!locked)
                SMSC_UNLOCK(sc);

        return (err);
}

/**
 *      smsc_miibus_readreg - Reads a MII/MDIO register
 *      @dev: usb ether device
 *      @phy: the number of phy reading from
 *      @reg: the register address
 *
 *      Attempts to read a phy register over the MII bus.
 *
 *      LOCKING:
 *      Takes and releases the device mutex lock if not already held.
 *
 *      RETURNS:
 *      Returns the 16-bits read from the MII register, if this function fails 0
 *      is returned.
 */
static int
smsc_miibus_readreg(device_t dev, int phy, int reg)
{
        struct smsc_softc *sc = device_get_softc(dev);
        int locked;
        uint32_t addr;
        uint32_t val = 0;

        locked = mtx_owned(&sc->sc_mtx);
        if (!locked)
                SMSC_LOCK(sc);

        if (smsc_wait_for_bits(sc, SMSC_MII_ADDR, SMSC_MII_BUSY) != 0) {
                smsc_warn_printf(sc, "MII is busy\n");
                goto done;
        }

        addr = (phy << 11) | (reg << 6) | SMSC_MII_READ | SMSC_MII_BUSY;
        smsc_write_reg(sc, SMSC_MII_ADDR, addr);

        if (smsc_wait_for_bits(sc, SMSC_MII_ADDR, SMSC_MII_BUSY) != 0)
                smsc_warn_printf(sc, "MII read timeout\n");

        smsc_read_reg(sc, SMSC_MII_DATA, &val);
        val = le32toh(val);

done:
        if (!locked)
                SMSC_UNLOCK(sc);

        return (val & 0xFFFF);
}

/**
 *      smsc_miibus_writereg - Writes a MII/MDIO register
 *      @dev: usb ether device
 *      @phy: the number of phy writing to
 *      @reg: the register address
 *      @val: the value to write
 *
 *      Attempts to write a phy register over the MII bus.
 *
 *      LOCKING:
 *      Takes and releases the device mutex lock if not already held.
 *
 *      RETURNS:
 *      Always returns 0 regardless of success or failure.
 */
static int
smsc_miibus_writereg(device_t dev, int phy, int reg, int val)
{
        struct smsc_softc *sc = device_get_softc(dev);
        int locked;
        uint32_t addr;

        if (sc->sc_phyno != phy)
                return (0);

        locked = mtx_owned(&sc->sc_mtx);
        if (!locked)
                SMSC_LOCK(sc);

        if (smsc_wait_for_bits(sc, SMSC_MII_ADDR, SMSC_MII_BUSY) != 0) {
                smsc_warn_printf(sc, "MII is busy\n");
                goto done;
        }

        val = htole32(val);
        smsc_write_reg(sc, SMSC_MII_DATA, val);

        addr = (phy << 11) | (reg << 6) | SMSC_MII_WRITE | SMSC_MII_BUSY;
        smsc_write_reg(sc, SMSC_MII_ADDR, addr);

        if (smsc_wait_for_bits(sc, SMSC_MII_ADDR, SMSC_MII_BUSY) != 0)
                smsc_warn_printf(sc, "MII write timeout\n");

done:
        if (!locked)
                SMSC_UNLOCK(sc);
        return (0);
}

/**
 *      smsc_miibus_statchg - Called to detect phy status change
 *      @dev: usb ether device
 *
 *      This function is called periodically by the system to poll for status
 *      changes of the link.
 *
 *      LOCKING:
 *      Takes and releases the device mutex lock if not already held.
 */
static void
smsc_miibus_statchg(device_t dev)
{
        struct smsc_softc *sc = device_get_softc(dev);
        struct mii_data *mii = uether_getmii(&sc->sc_ue);
        if_t ifp;
        int locked;
        int err;
        uint32_t flow;
        uint32_t afc_cfg;

        locked = mtx_owned(&sc->sc_mtx);
        if (!locked)
                SMSC_LOCK(sc);

        ifp = uether_getifp(&sc->sc_ue);
        if (mii == NULL || ifp == NULL ||
            (if_getdrvflags(ifp) & IFF_DRV_RUNNING) == 0)
                goto done;

        /* Use the MII status to determine link status */
        sc->sc_flags &= ~SMSC_FLAG_LINK;
        if ((mii->mii_media_status & (IFM_ACTIVE | IFM_AVALID)) ==
            (IFM_ACTIVE | IFM_AVALID)) {
                switch (IFM_SUBTYPE(mii->mii_media_active)) {
                        case IFM_10_T:
                        case IFM_100_TX:
                                sc->sc_flags |= SMSC_FLAG_LINK;
                                break;
                        case IFM_1000_T:
                                /* Gigabit ethernet not supported by chipset */
                                break;
                        default:
                                break;
                }
        }

        /* Lost link, do nothing. */
        if ((sc->sc_flags & SMSC_FLAG_LINK) == 0) {
                smsc_dbg_printf(sc, "link flag not set\n");
                goto done;
        }

        err = smsc_read_reg(sc, SMSC_AFC_CFG, &afc_cfg);
        if (err) {
                smsc_warn_printf(sc, "failed to read initial AFC_CFG, error %d\n", err);
                goto done;
        }

        /* Enable/disable full duplex operation and TX/RX pause */
        if ((IFM_OPTIONS(mii->mii_media_active) & IFM_FDX) != 0) {
                smsc_dbg_printf(sc, "full duplex operation\n");
                sc->sc_mac_csr &= ~SMSC_MAC_CSR_RCVOWN;
                sc->sc_mac_csr |= SMSC_MAC_CSR_FDPX;

                if ((IFM_OPTIONS(mii->mii_media_active) & IFM_ETH_RXPAUSE) != 0)
                        flow = 0xffff0002;
                else
                        flow = 0;
                        
                if ((IFM_OPTIONS(mii->mii_media_active) & IFM_ETH_TXPAUSE) != 0)
                        afc_cfg |= 0xf;
                else
                        afc_cfg &= ~0xf;
                
        } else {
                smsc_dbg_printf(sc, "half duplex operation\n");
                sc->sc_mac_csr &= ~SMSC_MAC_CSR_FDPX;
                sc->sc_mac_csr |= SMSC_MAC_CSR_RCVOWN;
                
                flow = 0;
                afc_cfg |= 0xf;
        }

        err = smsc_write_reg(sc, SMSC_MAC_CSR, sc->sc_mac_csr);
        err += smsc_write_reg(sc, SMSC_FLOW, flow);
        err += smsc_write_reg(sc, SMSC_AFC_CFG, afc_cfg);
        if (err)
                smsc_warn_printf(sc, "media change failed, error %d\n", err);

done:
        if (!locked)
                SMSC_UNLOCK(sc);
}

/**
 *      smsc_ifmedia_upd - Set media options
 *      @ifp: interface pointer
 *
 *      Basically boilerplate code that simply calls the mii functions to set the
 *      media options.
 *
 *      LOCKING:
 *      The device lock must be held before this function is called.
 *
 *      RETURNS:
 *      Returns 0 on success or a negative error code.
 */
static int
smsc_ifmedia_upd(if_t ifp)
{
        struct smsc_softc *sc = if_getsoftc(ifp);
        struct mii_data *mii = uether_getmii(&sc->sc_ue);
        struct mii_softc *miisc;
        int err;

        SMSC_LOCK_ASSERT(sc, MA_OWNED);

        LIST_FOREACH(miisc, &mii->mii_phys, mii_list)
                PHY_RESET(miisc);
        err = mii_mediachg(mii);
        return (err);
}

/**
 *      smsc_ifmedia_sts - Report current media status
 *      @ifp: inet interface pointer
 *      @ifmr: interface media request
 *
 *      Basically boilerplate code that simply calls the mii functions to get the
 *      media status.
 *
 *      LOCKING:
 *      Internally takes and releases the device lock.
 */
static void
smsc_ifmedia_sts(if_t ifp, struct ifmediareq *ifmr)
{
        struct smsc_softc *sc = if_getsoftc(ifp);
        struct mii_data *mii = uether_getmii(&sc->sc_ue);

        SMSC_LOCK(sc);
        mii_pollstat(mii);
        ifmr->ifm_active = mii->mii_media_active;
        ifmr->ifm_status = mii->mii_media_status;
        SMSC_UNLOCK(sc);
}

/**
 *      smsc_hash - Calculate the hash of a mac address
 *      @addr: The mac address to calculate the hash on
 *
 *      This function is used when configuring a range of m'cast mac addresses to
 *      filter on.  The hash of the mac address is put in the device's mac hash
 *      table.
 *
 *      RETURNS:
 *      Returns a value from 0-63 value which is the hash of the mac address.
 */
static inline uint32_t
smsc_hash(uint8_t addr[ETHER_ADDR_LEN])
{
        return (ether_crc32_be(addr, ETHER_ADDR_LEN) >> 26) & 0x3f;
}

static u_int
smsc_hash_maddr(void *arg, struct sockaddr_dl *sdl, u_int cnt)
{
        uint32_t hash, *hashtbl = arg;

        hash = smsc_hash(LLADDR(sdl));
        hashtbl[hash >> 5] |= 1 << (hash & 0x1F);

        return (1);
}

/**
 *      smsc_setmulti - Setup multicast
 *      @ue: usb ethernet device context
 *
 *      Tells the device to either accept frames with a multicast mac address, a
 *      select group of m'cast mac addresses or just the devices mac address.
 *
 *      LOCKING:
 *      Should be called with the SMSC lock held.
 */
static void
smsc_setmulti(struct usb_ether *ue)
{
        struct smsc_softc *sc = uether_getsc(ue);
        if_t ifp = uether_getifp(ue);
        uint32_t hashtbl[2] = { 0, 0 };

        SMSC_LOCK_ASSERT(sc, MA_OWNED);

        if (if_getflags(ifp) & (IFF_ALLMULTI | IFF_PROMISC)) {
                smsc_dbg_printf(sc, "receive all multicast enabled\n");
                sc->sc_mac_csr |= SMSC_MAC_CSR_MCPAS;
                sc->sc_mac_csr &= ~SMSC_MAC_CSR_HPFILT;
                
        } else {
                if (if_foreach_llmaddr(ifp, smsc_hash_maddr, &hashtbl) > 0) {
                        /* We are filtering on a set of address so calculate
                         * hashes of each of the address and set the
                         * corresponding bits in the register.
                         */
                        sc->sc_mac_csr |= SMSC_MAC_CSR_HPFILT;
                        sc->sc_mac_csr &= ~(SMSC_MAC_CSR_PRMS | SMSC_MAC_CSR_MCPAS);
                } else {
                        /* Only receive packets with destination set to
                         * our mac address
                         */
                        sc->sc_mac_csr &= ~(SMSC_MAC_CSR_MCPAS | SMSC_MAC_CSR_HPFILT);
                }
                
                /* Debug */
                if (sc->sc_mac_csr & SMSC_MAC_CSR_HPFILT)
                        smsc_dbg_printf(sc, "receive select group of macs\n");
                else
                        smsc_dbg_printf(sc, "receive own packets only\n");
        }

        /* Write the hash table and mac control registers */
        smsc_write_reg(sc, SMSC_HASHH, hashtbl[1]);
        smsc_write_reg(sc, SMSC_HASHL, hashtbl[0]);
        smsc_write_reg(sc, SMSC_MAC_CSR, sc->sc_mac_csr);
}

/**
 *      smsc_setpromisc - Enables/disables promiscuous mode
 *      @ue: usb ethernet device context
 *
 *      LOCKING:
 *      Should be called with the SMSC lock held.
 */
static void
smsc_setpromisc(struct usb_ether *ue)
{
        struct smsc_softc *sc = uether_getsc(ue);
        if_t ifp = uether_getifp(ue);

        smsc_dbg_printf(sc, "promiscuous mode %sabled\n",
                        (if_getflags(ifp) & IFF_PROMISC) ? "en" : "dis");

        SMSC_LOCK_ASSERT(sc, MA_OWNED);

        if (if_getflags(ifp) & IFF_PROMISC)
                sc->sc_mac_csr |= SMSC_MAC_CSR_PRMS;
        else
                sc->sc_mac_csr &= ~SMSC_MAC_CSR_PRMS;

        smsc_write_reg(sc, SMSC_MAC_CSR, sc->sc_mac_csr);
}

/**
 *      smsc_sethwcsum - Enable or disable H/W UDP and TCP checksumming
 *      @sc: driver soft context
 *
 *      LOCKING:
 *      Should be called with the SMSC lock held.
 *
 *      RETURNS:
 *      Returns 0 on success or a negative error code.
 */
static int smsc_sethwcsum(struct smsc_softc *sc)
{
        if_t ifp = uether_getifp(&sc->sc_ue);
        uint32_t val;
        int err;

        if (!ifp)
                return (-EIO);

        SMSC_LOCK_ASSERT(sc, MA_OWNED);

        err = smsc_read_reg(sc, SMSC_COE_CTRL, &val);
        if (err != 0) {
                smsc_warn_printf(sc, "failed to read SMSC_COE_CTRL (err=%d)\n", err);
                return (err);
        }

        /* Enable/disable the Rx checksum */
        if ((if_getcapabilities(ifp) & if_getcapenable(ifp)) & IFCAP_RXCSUM)
                val |= SMSC_COE_CTRL_RX_EN;
        else
                val &= ~SMSC_COE_CTRL_RX_EN;

        /* Enable/disable the Tx checksum (currently not supported) */
        if ((if_getcapabilities(ifp) & if_getcapenable(ifp)) & IFCAP_TXCSUM)
                val |= SMSC_COE_CTRL_TX_EN;
        else
                val &= ~SMSC_COE_CTRL_TX_EN;

        err = smsc_write_reg(sc, SMSC_COE_CTRL, val);
        if (err != 0) {
                smsc_warn_printf(sc, "failed to write SMSC_COE_CTRL (err=%d)\n", err);
                return (err);
        }

        return (0);
}

/**
 *      smsc_setmacaddress - Sets the mac address in the device
 *      @sc: driver soft context
 *      @addr: pointer to array contain at least 6 bytes of the mac
 *
 *      Writes the MAC address into the device, usually the MAC is programmed with
 *      values from the EEPROM.
 *
 *      LOCKING:
 *      Should be called with the SMSC lock held.
 *
 *      RETURNS:
 *      Returns 0 on success or a negative error code.
 */
static int
smsc_setmacaddress(struct smsc_softc *sc, const uint8_t *addr)
{
        int err;
        uint32_t val;

        smsc_dbg_printf(sc, "setting mac address to %02x:%02x:%02x:%02x:%02x:%02x\n",
                        addr[0], addr[1], addr[2], addr[3], addr[4], addr[5]);

        SMSC_LOCK_ASSERT(sc, MA_OWNED);

        val = (addr[3] << 24) | (addr[2] << 16) | (addr[1] << 8) | addr[0];
        if ((err = smsc_write_reg(sc, SMSC_MAC_ADDRL, val)) != 0)
                goto done;
                
        val = (addr[5] << 8) | addr[4];
        err = smsc_write_reg(sc, SMSC_MAC_ADDRH, val);

done:
        return (err);
}

/**
 *      smsc_reset - Reset the SMSC chip
 *      @sc: device soft context
 *
 *      LOCKING:
 *      Should be called with the SMSC lock held.
 */
static void
smsc_reset(struct smsc_softc *sc)
{
        struct usb_config_descriptor *cd;
        usb_error_t err;

        cd = usbd_get_config_descriptor(sc->sc_ue.ue_udev);

        err = usbd_req_set_config(sc->sc_ue.ue_udev, &sc->sc_mtx,
                                  cd->bConfigurationValue);
        if (err)
                smsc_warn_printf(sc, "reset failed (ignored)\n");

        /* Wait a little while for the chip to get its brains in order. */
        uether_pause(&sc->sc_ue, hz / 100);

        /* Reinitialize controller to achieve full reset. */
        smsc_chip_init(sc);
}

/**
 *      smsc_init - Initialises the LAN95xx chip
 *      @ue: USB ether interface
 *
 *      Called when the interface is brought up (i.e. ifconfig ue0 up), this
 *      initialise the interface and the rx/tx pipes.
 *
 *      LOCKING:
 *      Should be called with the SMSC lock held.
 */
static void
smsc_init(struct usb_ether *ue)
{
        struct smsc_softc *sc = uether_getsc(ue);
        if_t ifp = uether_getifp(ue);

        SMSC_LOCK_ASSERT(sc, MA_OWNED);

        if (smsc_setmacaddress(sc, if_getlladdr(ifp)))
                smsc_dbg_printf(sc, "setting MAC address failed\n");

        if ((if_getdrvflags(ifp) & IFF_DRV_RUNNING) != 0)
                return;

        /* Cancel pending I/O */
        smsc_stop(ue);

        /* Reset the ethernet interface. */
        smsc_reset(sc);

        /* Load the multicast filter. */
        smsc_setmulti(ue);

        /* TCP/UDP checksum offload engines. */
        smsc_sethwcsum(sc);

        usbd_xfer_set_stall(sc->sc_xfer[SMSC_BULK_DT_WR]);

        /* Indicate we are up and running. */
        if_setdrvflagbits(ifp, IFF_DRV_RUNNING, 0);

        /* Switch to selected media. */
        smsc_ifmedia_upd(ifp);
        smsc_start(ue);
}

/**
 *      smsc_bulk_read_callback - Read callback used to process the USB URB
 *      @xfer: the USB transfer
 *      @error: 
 *
 *      Reads the URB data which can contain one or more ethernet frames, the
 *      frames are copyed into a mbuf and given to the system.
 *
 *      LOCKING:
 *      No locking required, doesn't access internal driver settings.
 */
static void
smsc_bulk_read_callback(struct usb_xfer *xfer, usb_error_t error)
{
        struct smsc_softc *sc = usbd_xfer_softc(xfer);
        struct usb_ether *ue = &sc->sc_ue;
        if_t ifp = uether_getifp(ue);
        struct mbuf *m;
        struct usb_page_cache *pc;
        uint32_t rxhdr;
        int pktlen;
        int off;
        int actlen;

        usbd_xfer_status(xfer, &actlen, NULL, NULL, NULL);
        smsc_dbg_printf(sc, "rx : actlen %d\n", actlen);

        switch (USB_GET_STATE(xfer)) {
        case USB_ST_TRANSFERRED:

                /* There is always a zero length frame after bringing the IF up */
                if (actlen < (sizeof(rxhdr) + ETHER_CRC_LEN))
                        goto tr_setup;

                /* There maybe multiple packets in the USB frame, each will have a 
                 * header and each needs to have it's own mbuf allocated and populated
                 * for it.
                 */
                pc = usbd_xfer_get_frame(xfer, 0);
                off = 0;
                
                while (off < actlen) {
                
                        /* The frame header is always aligned on a 4 byte boundary */
                        off = ((off + 0x3) & ~0x3);

                        if ((off + sizeof(rxhdr)) > actlen)
                                goto tr_setup;

                        usbd_copy_out(pc, off, &rxhdr, sizeof(rxhdr));
                        off += (sizeof(rxhdr) + ETHER_ALIGN);
                        rxhdr = le32toh(rxhdr);
                
                        pktlen = (uint16_t)SMSC_RX_STAT_FRM_LENGTH(rxhdr);
                        
                        smsc_dbg_printf(sc, "rx : rxhdr 0x%08x : pktlen %d : actlen %d : "
                                        "off %d\n", rxhdr, pktlen, actlen, off);

                        
                        if (rxhdr & SMSC_RX_STAT_ERROR) {
                                smsc_dbg_printf(sc, "rx error (hdr 0x%08x)\n", rxhdr);
                                if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
                                if (rxhdr & SMSC_RX_STAT_COLLISION)
                                        if_inc_counter(ifp, IFCOUNTER_COLLISIONS, 1);
                        } else {
                                /* Check if the ethernet frame is too big or too small */
                                if ((pktlen < ETHER_HDR_LEN) || (pktlen > (actlen - off)))
                                        goto tr_setup;
                        
                                /* Create a new mbuf to store the packet in */
                                m = uether_newbuf();
                                if (m == NULL) {
                                        smsc_warn_printf(sc, "failed to create new mbuf\n");
                                        if_inc_counter(ifp, IFCOUNTER_IQDROPS, 1);
                                        goto tr_setup;
                                }
                                if (pktlen > m->m_len) {
                                        smsc_dbg_printf(sc, "buffer too small %d vs %d bytes",
                                            pktlen, m->m_len);
                                        if_inc_counter(ifp, IFCOUNTER_IQDROPS, 1);
                                        m_freem(m);
                                        goto tr_setup;
                                }
                                usbd_copy_out(pc, off, mtod(m, uint8_t *), pktlen);

                                /* Check if RX TCP/UDP checksumming is being offloaded */
                                if ((if_getcapenable(ifp) & IFCAP_RXCSUM) != 0) {
                                        struct ether_header *eh;

                                        eh = mtod(m, struct ether_header *);
                                
                                        /* Remove the extra 2 bytes of the csum */
                                        pktlen -= 2;

                                        /* The checksum appears to be simplistically calculated
                                         * over the udp/tcp header and data up to the end of the
                                         * eth frame.  Which means if the eth frame is padded
                                         * the csum calculation is incorrectly performed over
                                         * the padding bytes as well. Therefore to be safe we
                                         * ignore the H/W csum on frames less than or equal to
                                         * 64 bytes.
                                         *
                                         * Ignore H/W csum for non-IPv4 packets.
                                         */
                                        if ((be16toh(eh->ether_type) == ETHERTYPE_IP) &&
                                            (pktlen > ETHER_MIN_LEN)) {
                                                struct ip *ip;

                                                ip = (struct ip *)(eh + 1);
                                                if ((ip->ip_v == IPVERSION) &&
                                                    ((ip->ip_p == IPPROTO_TCP) ||
                                                     (ip->ip_p == IPPROTO_UDP))) {
                                                        /* Indicate the UDP/TCP csum has been calculated */
                                                        m->m_pkthdr.csum_flags |= CSUM_DATA_VALID;

                                                        /* Copy the TCP/UDP checksum from the last 2 bytes
                                                         * of the transfer and put in the csum_data field.
                                                         */
                                                        usbd_copy_out(pc, (off + pktlen),
                                                                      &m->m_pkthdr.csum_data, 2);

                                                        /* The data is copied in network order, but the
                                                         * csum algorithm in the kernel expects it to be
                                                         * in host network order.
                                                         */
                                                        m->m_pkthdr.csum_data = ntohs(m->m_pkthdr.csum_data);

                                                        smsc_dbg_printf(sc, "RX checksum offloaded (0x%04x)\n",
                                                                        m->m_pkthdr.csum_data);
                                                }
                                        }
                                        
                                        /* Need to adjust the offset as well or we'll be off
                                         * by 2 because the csum is removed from the packet
                                         * length.
                                         */
                                        off += 2;
                                }
                        
                                /* Finally enqueue the mbuf on the receive queue */
                                /* Remove 4 trailing bytes */
                                if (pktlen < (4 + ETHER_HDR_LEN)) {
                                        m_freem(m);
                                        goto tr_setup;
                                }
                                uether_rxmbuf(ue, m, pktlen - 4);
                        }

                        /* Update the offset to move to the next potential packet */
                        off += pktlen;
                }

                /* FALLTHROUGH */
                
        case USB_ST_SETUP:
tr_setup:
                usbd_xfer_set_frame_len(xfer, 0, usbd_xfer_max_len(xfer));
                usbd_transfer_submit(xfer);
                uether_rxflush(ue);
                return;

        default:
                if (error != USB_ERR_CANCELLED) {
                        smsc_warn_printf(sc, "bulk read error, %s\n", usbd_errstr(error));
                        usbd_xfer_set_stall(xfer);
                        goto tr_setup;
                }
                return;
        }
}

/**
 *      smsc_bulk_write_callback - Write callback used to send ethernet frame(s)
 *      @xfer: the USB transfer
 *      @error: error code if the transfers is in an errored state
 *
 *      The main write function that pulls ethernet frames off the queue and sends
 *      them out.
 *
 *      LOCKING:
 *      
 */
static void
smsc_bulk_write_callback(struct usb_xfer *xfer, usb_error_t error)
{
        struct smsc_softc *sc = usbd_xfer_softc(xfer);
        if_t ifp = uether_getifp(&sc->sc_ue);
        struct usb_page_cache *pc;
        struct mbuf *m;
        uint32_t txhdr;
        uint32_t frm_len = 0;
        int nframes;

        switch (USB_GET_STATE(xfer)) {
        case USB_ST_TRANSFERRED:
                if_setdrvflagbits(ifp, 0, IFF_DRV_OACTIVE);
                /* FALLTHROUGH */

        case USB_ST_SETUP:
tr_setup:
                if ((sc->sc_flags & SMSC_FLAG_LINK) == 0 ||
                        (if_getdrvflags(ifp) & IFF_DRV_OACTIVE) != 0) {
                        /* Don't send anything if there is no link or controller is busy. */
                        return;
                }

                for (nframes = 0; nframes < 16 &&
                    !if_sendq_empty(ifp); nframes++) {
                        m = if_dequeue(ifp);
                        if (m == NULL)
                                break;
                        usbd_xfer_set_frame_offset(xfer, nframes * MCLBYTES,
                            nframes);
                        frm_len = 0;
                        pc = usbd_xfer_get_frame(xfer, nframes);

                        /* Each frame is prefixed with two 32-bit values describing the
                         * length of the packet and buffer.
                         */
                        txhdr = SMSC_TX_CTRL_0_BUF_SIZE(m->m_pkthdr.len) | 
                                        SMSC_TX_CTRL_0_FIRST_SEG | SMSC_TX_CTRL_0_LAST_SEG;
                        txhdr = htole32(txhdr);
                        usbd_copy_in(pc, 0, &txhdr, sizeof(txhdr));
                        
                        txhdr = SMSC_TX_CTRL_1_PKT_LENGTH(m->m_pkthdr.len);
                        txhdr = htole32(txhdr);
                        usbd_copy_in(pc, 4, &txhdr, sizeof(txhdr));
                        
                        frm_len += 8;

                        /* Next copy in the actual packet */
                        usbd_m_copy_in(pc, frm_len, m, 0, m->m_pkthdr.len);
                        frm_len += m->m_pkthdr.len;

                        if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);

                        /* If there's a BPF listener, bounce a copy of this frame to him */
                        BPF_MTAP(ifp, m);

                        m_freem(m);

                        /* Set frame length. */
                        usbd_xfer_set_frame_len(xfer, nframes, frm_len);
                }
                if (nframes != 0) {
                        usbd_xfer_set_frames(xfer, nframes);
                        usbd_transfer_submit(xfer);
                        if_setdrvflagbits(ifp, IFF_DRV_OACTIVE, 0);
                }
                return;

        default:
                if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
                if_setdrvflagbits(ifp, 0, IFF_DRV_OACTIVE);
                
                if (error != USB_ERR_CANCELLED) {
                        smsc_err_printf(sc, "usb error on tx: %s\n", usbd_errstr(error));
                        usbd_xfer_set_stall(xfer);
                        goto tr_setup;
                }
                return;
        }
}

/**
 *      smsc_tick - Called periodically to monitor the state of the LAN95xx chip
 *      @ue: USB ether interface
 *
 *      Simply calls the mii status functions to check the state of the link.
 *
 *      LOCKING:
 *      Should be called with the SMSC lock held.
 */
static void
smsc_tick(struct usb_ether *ue)
{
        struct smsc_softc *sc = uether_getsc(ue);
        struct mii_data *mii = uether_getmii(&sc->sc_ue);

        SMSC_LOCK_ASSERT(sc, MA_OWNED);

        mii_tick(mii);
        if ((sc->sc_flags & SMSC_FLAG_LINK) == 0) {
                smsc_miibus_statchg(ue->ue_dev);
                if ((sc->sc_flags & SMSC_FLAG_LINK) != 0)
                        smsc_start(ue);
        }
}

/**
 *      smsc_start - Starts communication with the LAN95xx chip
 *      @ue: USB ether interface
 *
 *      
 *
 */
static void
smsc_start(struct usb_ether *ue)
{
        struct smsc_softc *sc = uether_getsc(ue);

        /*
         * start the USB transfers, if not already started:
         */
        usbd_transfer_start(sc->sc_xfer[SMSC_BULK_DT_RD]);
        usbd_transfer_start(sc->sc_xfer[SMSC_BULK_DT_WR]);
}

/**
 *      smsc_stop - Stops communication with the LAN95xx chip
 *      @ue: USB ether interface
 *
 *      
 *
 */
static void
smsc_stop(struct usb_ether *ue)
{
        struct smsc_softc *sc = uether_getsc(ue);
        if_t ifp = uether_getifp(ue);

        SMSC_LOCK_ASSERT(sc, MA_OWNED);

        if_setdrvflagbits(ifp, 0, (IFF_DRV_RUNNING | IFF_DRV_OACTIVE));
        sc->sc_flags &= ~SMSC_FLAG_LINK;

        /*
         * stop all the transfers, if not already stopped:
         */
        usbd_transfer_stop(sc->sc_xfer[SMSC_BULK_DT_WR]);
        usbd_transfer_stop(sc->sc_xfer[SMSC_BULK_DT_RD]);
}

/**
 *      smsc_phy_init - Initialises the in-built SMSC phy
 *      @sc: driver soft context
 *
 *      Resets the PHY part of the chip and then initialises it to default
 *      values.  The 'link down' and 'auto-negotiation complete' interrupts
 *      from the PHY are also enabled, however we don't monitor the interrupt
 *      endpoints for the moment.
 *
 *      RETURNS:
 *      Returns 0 on success or EIO if failed to reset the PHY.
 */
static int
smsc_phy_init(struct smsc_softc *sc)
{
        int bmcr;
        usb_ticks_t start_ticks;
        const usb_ticks_t max_ticks = USB_MS_TO_TICKS(1000);

        SMSC_LOCK_ASSERT(sc, MA_OWNED);

        /* Reset phy and wait for reset to complete */
        smsc_miibus_writereg(sc->sc_ue.ue_dev, sc->sc_phyno, MII_BMCR, BMCR_RESET);

        start_ticks = ticks;
        do {
                uether_pause(&sc->sc_ue, hz / 100);
                bmcr = smsc_miibus_readreg(sc->sc_ue.ue_dev, sc->sc_phyno, MII_BMCR);
        } while ((bmcr & BMCR_RESET) && ((ticks - start_ticks) < max_ticks));

        if (((usb_ticks_t)(ticks - start_ticks)) >= max_ticks) {
                smsc_err_printf(sc, "PHY reset timed-out\n");
                return (EIO);
        }

        smsc_miibus_writereg(sc->sc_ue.ue_dev, sc->sc_phyno, MII_ANAR,
                             ANAR_10 | ANAR_10_FD | ANAR_TX | ANAR_TX_FD |  /* all modes */
                             ANAR_CSMA | 
                             ANAR_FC |
                             ANAR_PAUSE_ASYM);

        /* Setup the phy to interrupt when the link goes down or autoneg completes */
        smsc_miibus_readreg(sc->sc_ue.ue_dev, sc->sc_phyno, SMSC_PHY_INTR_STAT);
        smsc_miibus_writereg(sc->sc_ue.ue_dev, sc->sc_phyno, SMSC_PHY_INTR_MASK,
                             (SMSC_PHY_INTR_ANEG_COMP | SMSC_PHY_INTR_LINK_DOWN));

        /* Restart auto-negotiation */
        bmcr = smsc_miibus_readreg(sc->sc_ue.ue_dev, sc->sc_phyno, MII_BMCR);
        bmcr |= BMCR_STARTNEG;
        smsc_miibus_writereg(sc->sc_ue.ue_dev, sc->sc_phyno, MII_BMCR, bmcr);

        return (0);
}

/**
 *      smsc_chip_init - Initialises the chip after power on
 *      @sc: driver soft context
 *
 *      This initialisation sequence is modelled on the procedure in the Linux
 *      driver.
 *
 *      RETURNS:
 *      Returns 0 on success or an error code on failure.
 */
static int
smsc_chip_init(struct smsc_softc *sc)
{
        int err;
        int locked;
        uint32_t reg_val;
        int burst_cap;

        locked = mtx_owned(&sc->sc_mtx);
        if (!locked)
                SMSC_LOCK(sc);

        /* Enter H/W config mode */
        smsc_write_reg(sc, SMSC_HW_CFG, SMSC_HW_CFG_LRST);

        if ((err = smsc_wait_for_bits(sc, SMSC_HW_CFG, SMSC_HW_CFG_LRST)) != 0) {
                smsc_warn_printf(sc, "timed-out waiting for reset to complete\n");
                goto init_failed;
        }

        /* Reset the PHY */
        smsc_write_reg(sc, SMSC_PM_CTRL, SMSC_PM_CTRL_PHY_RST);

        if ((err = smsc_wait_for_bits(sc, SMSC_PM_CTRL, SMSC_PM_CTRL_PHY_RST)) != 0) {
                smsc_warn_printf(sc, "timed-out waiting for phy reset to complete\n");
                goto init_failed;
        }

        /* Set the mac address */
        if ((err = smsc_setmacaddress(sc, sc->sc_ue.ue_eaddr)) != 0) {
                smsc_warn_printf(sc, "failed to set the MAC address\n");
                goto init_failed;
        }

        /* Don't know what the HW_CFG_BIR bit is, but following the reset sequence
         * as used in the Linux driver.
         */
        if ((err = smsc_read_reg(sc, SMSC_HW_CFG, &reg_val)) != 0) {
                smsc_warn_printf(sc, "failed to read HW_CFG: %d\n", err);
                goto init_failed;
        }
        reg_val |= SMSC_HW_CFG_BIR;
        smsc_write_reg(sc, SMSC_HW_CFG, reg_val);

        /* There is a so called 'turbo mode' that the linux driver supports, it
         * seems to allow you to jam multiple frames per Rx transaction.  By default
         * this driver supports that and therefore allows multiple frames per URB.
         *
         * The xfer buffer size needs to reflect this as well, therefore based on
         * the calculations in the Linux driver the RX bufsize is set to 18944,
         *     bufsz = (16 * 1024 + 5 * 512)
         *
         * Burst capability is the number of URBs that can be in a burst of data/
         * ethernet frames.
         */
        if (!smsc_rx_packet_batching)
                burst_cap = 0;
        else if (usbd_get_speed(sc->sc_ue.ue_udev) == USB_SPEED_HIGH)
                burst_cap = 37;
        else
                burst_cap = 128;

        smsc_write_reg(sc, SMSC_BURST_CAP, burst_cap);

        /* Set the default bulk in delay (magic value from Linux driver) */
        smsc_write_reg(sc, SMSC_BULK_IN_DLY, 0x00002000);

        /*
         * Initialise the RX interface
         */
        if ((err = smsc_read_reg(sc, SMSC_HW_CFG, &reg_val)) < 0) {
                smsc_warn_printf(sc, "failed to read HW_CFG: (err = %d)\n", err);
                goto init_failed;
        }

        /* Adjust the packet offset in the buffer (designed to try and align IP
         * header on 4 byte boundary)
         */
        reg_val &= ~SMSC_HW_CFG_RXDOFF;
        reg_val |= (ETHER_ALIGN << 9) & SMSC_HW_CFG_RXDOFF;

        /* The following settings are used for 'turbo mode', a.k.a multiple frames
         * per Rx transaction (again info taken form Linux driver).
         */
        if (smsc_rx_packet_batching)
                reg_val |= (SMSC_HW_CFG_MEF | SMSC_HW_CFG_BCE);

        smsc_write_reg(sc, SMSC_HW_CFG, reg_val);

        /* Clear the status register ? */
        smsc_write_reg(sc, SMSC_INTR_STATUS, 0xffffffff);

        /* Read and display the revision register */
        if ((err = smsc_read_reg(sc, SMSC_ID_REV, &sc->sc_rev_id)) < 0) {
                smsc_warn_printf(sc, "failed to read ID_REV (err = %d)\n", err);
                goto init_failed;
        }

        device_printf(sc->sc_ue.ue_dev, "chip 0x%04lx, rev. %04lx\n", 
            (sc->sc_rev_id & SMSC_ID_REV_CHIP_ID_MASK) >> 16, 
            (sc->sc_rev_id & SMSC_ID_REV_CHIP_REV_MASK));

        /* GPIO/LED setup */
        reg_val = SMSC_LED_GPIO_CFG_SPD_LED | SMSC_LED_GPIO_CFG_LNK_LED | 
                  SMSC_LED_GPIO_CFG_FDX_LED;
        smsc_write_reg(sc, SMSC_LED_GPIO_CFG, reg_val);

        /*
         * Initialise the TX interface
         */
        smsc_write_reg(sc, SMSC_FLOW, 0);

        smsc_write_reg(sc, SMSC_AFC_CFG, AFC_CFG_DEFAULT);

        /* Read the current MAC configuration */
        if ((err = smsc_read_reg(sc, SMSC_MAC_CSR, &sc->sc_mac_csr)) < 0) {
                smsc_warn_printf(sc, "failed to read MAC_CSR (err=%d)\n", err);
                goto init_failed;
        }

        /* Vlan */
        smsc_write_reg(sc, SMSC_VLAN1, (uint32_t)ETHERTYPE_VLAN);

        /*
         * Initialise the PHY
         */
        if ((err = smsc_phy_init(sc)) != 0)
                goto init_failed;

        /*
         * Start TX
         */
        sc->sc_mac_csr |= SMSC_MAC_CSR_TXEN;
        smsc_write_reg(sc, SMSC_MAC_CSR, sc->sc_mac_csr);
        smsc_write_reg(sc, SMSC_TX_CFG, SMSC_TX_CFG_ON);

        /*
         * Start RX
         */
        sc->sc_mac_csr |= SMSC_MAC_CSR_RXEN;
        smsc_write_reg(sc, SMSC_MAC_CSR, sc->sc_mac_csr);

        if (!locked)
                SMSC_UNLOCK(sc);

        return (0);

init_failed:
        if (!locked)
                SMSC_UNLOCK(sc);

        smsc_err_printf(sc, "smsc_chip_init failed (err=%d)\n", err);
        return (err);
}

/**
 *      smsc_ioctl - ioctl function for the device
 *      @ifp: interface pointer
 *      @cmd: the ioctl command
 *      @data: data passed in the ioctl call, typically a pointer to struct ifreq.
 *      
 *      The ioctl routine is overridden to detect change requests for the H/W
 *      checksum capabilities.
 *
 *      RETURNS:
 *      0 on success and an error code on failure.
 */
static int
smsc_ioctl(if_t ifp, u_long cmd, caddr_t data)
{
        struct usb_ether *ue = if_getsoftc(ifp);
        struct smsc_softc *sc;
        struct ifreq *ifr;
        int rc;
        int mask;
        int reinit;

        if (cmd == SIOCSIFCAP) {
                sc = uether_getsc(ue);
                ifr = (struct ifreq *)data;

                SMSC_LOCK(sc);

                rc = 0;
                reinit = 0;

                mask = ifr->ifr_reqcap ^ if_getcapenable(ifp);

                /* Modify the RX CSUM enable bits */
                if ((mask & IFCAP_RXCSUM) != 0 &&
                    (if_getcapabilities(ifp) & IFCAP_RXCSUM) != 0) {
                        if_togglecapenable(ifp, IFCAP_RXCSUM);
                        
                        if (if_getdrvflags(ifp) & IFF_DRV_RUNNING) {
                                if_setdrvflagbits(ifp, 0, IFF_DRV_RUNNING);
                                reinit = 1;
                        }
                }
                
                SMSC_UNLOCK(sc);
                if (reinit)
                        uether_init(ue);

        } else {
                rc = uether_ioctl(ifp, cmd, data);
        }

        return (rc);
}

#ifdef FDT
static bool
smsc_get_smsc95xx_macaddr(char* bootargs, size_t len, struct usb_ether *ue)
{
        int values[6];
        int i;
        char* p;

        p = strnstr(bootargs, BOOTARGS_SMSC95XX, len);
        if (p == NULL)
                return (false);

        if (sscanf(p, BOOTARGS_SMSC95XX "=%x:%x:%x:%x:%x:%x%*c",
                        &values[0], &values[1], &values[2],
                        &values[3], &values[4], &values[5]) != 6) {
                smsc_warn_printf((struct smsc_softc *)ue->ue_sc,
                                "invalid mac from bootargs '%s'.\n", p);
                return (false);
        }

        for (i = 0; i < ETHER_ADDR_LEN; ++i)
                ue->ue_eaddr[i] = values[i];

        smsc_dbg_printf((struct smsc_softc *)ue->ue_sc,
                        "bootargs mac=%6D.\n", ue->ue_eaddr, ":");
        return (true);
}

/**
 * Raspberry Pi is known to pass smsc95xx.macaddr=XX:XX:XX:XX:XX:XX via
 * bootargs.
 */
static bool
smsc_bootargs_get_mac_addr(device_t dev, struct usb_ether *ue)
{
        char *bootargs;
        ssize_t len;
        phandle_t node;

        /* only use bootargs for the first device
         * to prevent duplicate mac addresses */
        if (device_get_unit(dev) != 0)
                return (false);
        node = OF_finddevice("/chosen");
        if (node == -1)
                return (false);
        if (!OF_hasprop(node, "bootargs")) {
                smsc_dbg_printf((struct smsc_softc *)ue->ue_sc,
                                "bootargs not found");
                return (false);
        }
        len = OF_getprop_alloc(node, "bootargs", (void **)&bootargs);
        if (len == -1 || bootargs == NULL) {
                smsc_warn_printf((struct smsc_softc *)ue->ue_sc,
                                "failed alloc for bootargs (%zd)", len);
                return (false);
        }
        smsc_dbg_printf((struct smsc_softc *)ue->ue_sc, "bootargs: %s.\n",
                        bootargs);
        if (!smsc_get_smsc95xx_macaddr(bootargs, len, ue)) {
                OF_prop_free(bootargs);
                return (false);
        }
        OF_prop_free(bootargs);
        device_printf(dev, "MAC address found in bootargs %6D.\n",
                        ue->ue_eaddr, ":");
        return (true);
}
#endif

/**
 *      smsc_attach_post - Called after the driver attached to the USB interface
 *      @ue: the USB ethernet device
 *
 *      This is where the chip is intialised for the first time.  This is different
 *      from the smsc_init() function in that that one is designed to setup the
 *      H/W to match the UE settings and can be called after a reset.
 *
 *
 */
static void
smsc_attach_post(struct usb_ether *ue)
{
        struct smsc_softc *sc = uether_getsc(ue);
        struct ether_addr eaddr;
        uint32_t mac_h, mac_l;
        int err;
        int i;

        smsc_dbg_printf(sc, "smsc_attach_post\n");

        /* Setup some of the basics */
        sc->sc_phyno = 1;

        /* Attempt to get the mac address, if an EEPROM is not attached this
         * will just return FF:FF:FF:FF:FF:FF, so in such cases we invent a MAC
         * address based on urandom.
         */
        memset(sc->sc_ue.ue_eaddr, 0xff, ETHER_ADDR_LEN);

        /* Check if there is already a MAC address in the register */
        if ((smsc_read_reg(sc, SMSC_MAC_ADDRL, &mac_l) == 0) &&
            (smsc_read_reg(sc, SMSC_MAC_ADDRH, &mac_h) == 0)) {
                sc->sc_ue.ue_eaddr[5] = (uint8_t)((mac_h >> 8) & 0xff);
                sc->sc_ue.ue_eaddr[4] = (uint8_t)((mac_h) & 0xff);
                sc->sc_ue.ue_eaddr[3] = (uint8_t)((mac_l >> 24) & 0xff);
                sc->sc_ue.ue_eaddr[2] = (uint8_t)((mac_l >> 16) & 0xff);
                sc->sc_ue.ue_eaddr[1] = (uint8_t)((mac_l >> 8) & 0xff);
                sc->sc_ue.ue_eaddr[0] = (uint8_t)((mac_l) & 0xff);
        }

        /* MAC address is not set so try to read from EEPROM, if that fails generate
         * a random MAC address.
         */
        if (!ETHER_IS_VALID(sc->sc_ue.ue_eaddr)) {
                err = smsc_eeprom_read(sc, 0x01, sc->sc_ue.ue_eaddr, ETHER_ADDR_LEN);
#ifdef FDT
                if ((err != 0) || (!ETHER_IS_VALID(sc->sc_ue.ue_eaddr)))
                        err = usb_fdt_get_mac_addr(sc->sc_ue.ue_dev, &sc->sc_ue);
                if ((err != 0) || (!ETHER_IS_VALID(sc->sc_ue.ue_eaddr)))
                        err = smsc_bootargs_get_mac_addr(sc->sc_ue.ue_dev,
                                        &sc->sc_ue) ? (0) : (1);
#endif
                if ((err != 0) || (!ETHER_IS_VALID(sc->sc_ue.ue_eaddr))) {
                        smsc_dbg_printf(sc, "No MAC address found."
                                        " Using ether_gen_addr().\n");
                        ether_gen_addr_byname(device_get_nameunit(ue->ue_dev),
                                        &eaddr);
                        for (i = 0; i < ETHER_ADDR_LEN; i++)
                                sc->sc_ue.ue_eaddr[i] = eaddr.octet[i];
                }
        }

        /* Initialise the chip for the first time */
        smsc_chip_init(sc);
}

/**
 *      smsc_attach_post_sub - Called after the driver attached to the USB interface
 *      @ue: the USB ethernet device
 *
 *      Most of this is boilerplate code and copied from the base USB ethernet
 *      driver.  It has been overridden so that we can indicate to the system that
 *      the chip supports H/W checksumming.
 *
 *      RETURNS:
 *      Returns 0 on success or a negative error code.
 */
static int
smsc_attach_post_sub(struct usb_ether *ue)
{
        struct smsc_softc *sc;
        if_t ifp;
        int error;

        sc = uether_getsc(ue);
        ifp = ue->ue_ifp;
        if_setflags(ifp, IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST);
        if_setstartfn(ifp, uether_start);
        if_setioctlfn(ifp, smsc_ioctl);
        if_setinitfn(ifp, uether_init);
        if_setsendqlen(ifp, ifqmaxlen);
        if_setsendqready(ifp);

        /* The chip supports TCP/UDP checksum offloading on TX and RX paths, however
         * currently only RX checksum is supported in the driver (see top of file).
         */
        if_setcapabilitiesbit(ifp, IFCAP_RXCSUM | IFCAP_VLAN_MTU, 0);
        if_sethwassist(ifp, 0);

        /* TX checksuming is disabled (for now?)
        if_setcapabilitiesbit(ifp, IFCAP_TXCSUM, 0);
        if_setcapenablebit(ifp, IFCAP_TXCSUM, 0);
        if_sethwassist(ifp, CSUM_TCP | CSUM_UDP);
        */

        if_setcapenable(ifp, if_getcapabilities(ifp));

        bus_topo_lock();
        error = mii_attach(ue->ue_dev, &ue->ue_miibus, ifp,
            uether_ifmedia_upd, ue->ue_methods->ue_mii_sts,
            BMSR_DEFCAPMASK, sc->sc_phyno, MII_OFFSET_ANY, 0);
        bus_topo_unlock();

        return (error);
}

/**
 *      smsc_probe - Probe the interface. 
 *      @dev: smsc device handle
 *
 *      Checks if the device is a match for this driver.
 *
 *      RETURNS:
 *      Returns 0 on success or an error code on failure.
 */
static int
smsc_probe(device_t dev)
{
        struct usb_attach_arg *uaa = device_get_ivars(dev);

        if (uaa->usb_mode != USB_MODE_HOST)
                return (ENXIO);
        if (uaa->info.bConfigIndex != SMSC_CONFIG_INDEX)
                return (ENXIO);
        if (uaa->info.bIfaceIndex != SMSC_IFACE_IDX)
                return (ENXIO);

        return (usbd_lookup_id_by_uaa(smsc_devs, sizeof(smsc_devs), uaa));
}

/**
 *      smsc_attach - Attach the interface. 
 *      @dev: smsc device handle
 *
 *      Allocate softc structures, do ifmedia setup and ethernet/BPF attach.
 *
 *      RETURNS:
 *      Returns 0 on success or a negative error code.
 */
static int
smsc_attach(device_t dev)
{
        struct usb_attach_arg *uaa = device_get_ivars(dev);
        struct smsc_softc *sc = device_get_softc(dev);
        struct usb_ether *ue = &sc->sc_ue;
        uint8_t iface_index;
        int err;

        sc->sc_flags = USB_GET_DRIVER_INFO(uaa);

        device_set_usb_desc(dev);

        mtx_init(&sc->sc_mtx, device_get_nameunit(dev), NULL, MTX_DEF);

        /* Setup the endpoints for the SMSC LAN95xx device(s) */
        iface_index = SMSC_IFACE_IDX;
        err = usbd_transfer_setup(uaa->device, &iface_index, sc->sc_xfer,
                                  smsc_config, SMSC_N_TRANSFER, sc, &sc->sc_mtx);
        if (err) {
                device_printf(dev, "error: allocating USB transfers failed\n");
                goto detach;
        }

        ue->ue_sc = sc;
        ue->ue_dev = dev;
        ue->ue_udev = uaa->device;
        ue->ue_mtx = &sc->sc_mtx;
        ue->ue_methods = &smsc_ue_methods;

        err = uether_ifattach(ue);
        if (err) {
                device_printf(dev, "error: could not attach interface\n");
                goto detach;
        }
        return (0);                     /* success */

detach:
        smsc_detach(dev);
        return (ENXIO);         /* failure */
}

/**
 *      smsc_detach - Detach the interface. 
 *      @dev: smsc device handle
 *
 *      RETURNS:
 *      Returns 0.
 */
static int
smsc_detach(device_t dev)
{
        struct smsc_softc *sc = device_get_softc(dev);
        struct usb_ether *ue = &sc->sc_ue;

        usbd_transfer_unsetup(sc->sc_xfer, SMSC_N_TRANSFER);
        uether_ifdetach(ue);
        mtx_destroy(&sc->sc_mtx);

        return (0);
}

static device_method_t smsc_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe, smsc_probe),
        DEVMETHOD(device_attach, smsc_attach),
        DEVMETHOD(device_detach, smsc_detach),

        /* bus interface */
        DEVMETHOD(bus_print_child, bus_generic_print_child),
        DEVMETHOD(bus_driver_added, bus_generic_driver_added),

        /* MII interface */
        DEVMETHOD(miibus_readreg, smsc_miibus_readreg),
        DEVMETHOD(miibus_writereg, smsc_miibus_writereg),
        DEVMETHOD(miibus_statchg, smsc_miibus_statchg),

        DEVMETHOD_END
};

static driver_t smsc_driver = {
        .name = "smsc",
        .methods = smsc_methods,
        .size = sizeof(struct smsc_softc),
};

DRIVER_MODULE(smsc, uhub, smsc_driver, NULL, NULL);
DRIVER_MODULE(miibus, smsc, miibus_driver, 0, 0);
MODULE_DEPEND(smsc, uether, 1, 1, 1);
MODULE_DEPEND(smsc, usb, 1, 1, 1);
MODULE_DEPEND(smsc, ether, 1, 1, 1);
MODULE_DEPEND(smsc, miibus, 1, 1, 1);
MODULE_VERSION(smsc, 1);
USB_PNP_HOST_INFO(smsc_devs);