kernel/if_re: Add support for the Realtek 8168H.

[dragonfly.git] / sys / dev / netif / re / if_re.c

/*
 * Copyright (c) 2004
 *      Joerg Sonnenberger <joerg@bec.de>.  All rights reserved.
 *
 * Copyright (c) 1997, 1998-2003
 *      Bill Paul <wpaul@windriver.com>.  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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Bill Paul.
 * 4. Neither the name of the author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``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 Bill Paul OR THE VOICES IN HIS HEAD
 * 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.
 *
 * $FreeBSD: src/sys/dev/re/if_re.c,v 1.25 2004/06/09 14:34:01 naddy Exp $
 */

/*
 * RealTek 8139C+/8169/8169S/8110S/8168/8111/8101E PCI NIC driver
 *
 * Written by Bill Paul <wpaul@windriver.com>
 * Senior Networking Software Engineer
 * Wind River Systems
 */

/*
 * This driver is designed to support RealTek's next generation of
 * 10/100 and 10/100/1000 PCI ethernet controllers. There are currently
 * seven devices in this family: the RTL8139C+, the RTL8169, the RTL8169S,
 * RTL8110S, the RTL8168, the RTL8111 and the RTL8101E.
 *
 * The 8139C+ is a 10/100 ethernet chip. It is backwards compatible
 * with the older 8139 family, however it also supports a special
 * C+ mode of operation that provides several new performance enhancing
 * features. These include:
 *
 *      o Descriptor based DMA mechanism. Each descriptor represents
 *        a single packet fragment. Data buffers may be aligned on
 *        any byte boundary.
 *
 *      o 64-bit DMA
 *
 *      o TCP/IP checksum offload for both RX and TX
 *
 *      o High and normal priority transmit DMA rings
 *
 *      o VLAN tag insertion and extraction
 *
 *      o TCP large send (segmentation offload)
 *
 * Like the 8139, the 8139C+ also has a built-in 10/100 PHY. The C+
 * programming API is fairly straightforward. The RX filtering, EEPROM
 * access and PHY access is the same as it is on the older 8139 series
 * chips.
 *
 * The 8169 is a 64-bit 10/100/1000 gigabit ethernet MAC. It has almost the
 * same programming API and feature set as the 8139C+ with the following
 * differences and additions:
 *
 *      o 1000Mbps mode
 *
 *      o Jumbo frames
 *
 *      o GMII and TBI ports/registers for interfacing with copper
 *        or fiber PHYs
 *
 *      o RX and TX DMA rings can have up to 1024 descriptors
 *        (the 8139C+ allows a maximum of 64)
 *
 *      o Slight differences in register layout from the 8139C+
 *
 * The TX start and timer interrupt registers are at different locations
 * on the 8169 than they are on the 8139C+. Also, the status word in the
 * RX descriptor has a slightly different bit layout. The 8169 does not
 * have a built-in PHY. Most reference boards use a Marvell 88E1000 'Alaska'
 * copper gigE PHY.
 *
 * The 8169S/8110S 10/100/1000 devices have built-in copper gigE PHYs
 * (the 'S' stands for 'single-chip'). These devices have the same
 * programming API as the older 8169, but also have some vendor-specific
 * registers for the on-board PHY. The 8110S is a LAN-on-motherboard
 * part designed to be pin-compatible with the RealTek 8100 10/100 chip.
 * 
 * This driver takes advantage of the RX and TX checksum offload and
 * VLAN tag insertion/extraction features. It also implements TX
 * interrupt moderation using the timer interrupt registers, which
 * significantly reduces TX interrupt load. There is also support
 * for jumbo frames, however the 8169/8169S/8110S can not transmit
 * jumbo frames larger than 7440, so the max MTU possible with this
 * driver is 7422 bytes.
 */

#define _IP_VHL

#include "opt_ifpoll.h"

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/endian.h>
#include <sys/kernel.h>
#include <sys/in_cksum.h>
#include <sys/interrupt.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/rman.h>
#include <sys/serialize.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/sysctl.h>

#include <net/bpf.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <net/ifq_var.h>
#include <net/if_arp.h>
#include <net/if_dl.h>
#include <net/if_media.h>
#include <net/if_poll.h>
#include <net/if_types.h>
#include <net/vlan/if_vlan_var.h>
#include <net/vlan/if_vlan_ether.h>

#include <netinet/ip.h>

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

#include "pcidevs.h"
#include <bus/pci/pcireg.h>
#include <bus/pci/pcivar.h>

/* "device miibus" required.  See GENERIC if you get errors here. */
#include "miibus_if.h"

#include <dev/netif/re/if_rereg.h>
#include <dev/netif/re/if_revar.h>

/*
 * Various supported device vendors/types and their names.
 */
static const struct re_type {
        uint16_t        re_vid;
        uint16_t        re_did;
        const char      *re_name;
} re_devs[] = {
        { PCI_VENDOR_DLINK, PCI_PRODUCT_DLINK_DGE528T,
          "D-Link DGE-528(T) Gigabit Ethernet Adapter" },

        { PCI_VENDOR_REALTEK, PCI_PRODUCT_REALTEK_RT8139,
          "RealTek 8139C+ 10/100BaseTX" },

        { PCI_VENDOR_REALTEK, PCI_PRODUCT_REALTEK_RT8101E,
          "RealTek 810x PCIe 10/100baseTX" },

        { PCI_VENDOR_REALTEK, PCI_PRODUCT_REALTEK_RT8168,
          "RealTek 8111/8168 PCIe Gigabit Ethernet" },

        { PCI_VENDOR_REALTEK, PCI_PRODUCT_REALTEK_RT8169,
          "RealTek 8110/8169 Gigabit Ethernet" },

        { PCI_VENDOR_REALTEK, PCI_PRODUCT_REALTEK_RT8169SC,
          "RealTek 8169SC/8110SC Single-chip Gigabit Ethernet" },

        { PCI_VENDOR_COREGA, PCI_PRODUCT_COREGA_CG_LAPCIGT,
          "Corega CG-LAPCIGT Gigabit Ethernet" },

        { PCI_VENDOR_LINKSYS, PCI_PRODUCT_LINKSYS_EG1032,
          "Linksys EG1032 Gigabit Ethernet" },

        { PCI_VENDOR_USR2, PCI_PRODUCT_USR2_997902,
          "US Robotics 997902 Gigabit Ethernet" },

        { PCI_VENDOR_TTTECH, PCI_PRODUCT_TTTECH_MC322,
          "TTTech MC322 Gigabit Ethernet" },

        { 0, 0, NULL }
};

static const struct re_hwrev re_hwrevs[] = {
        { RE_HWREV_8139CPLUS,   ETHERMTU,
          RE_C_HWCSUM | RE_C_8139CP | RE_C_FASTE },

        { RE_HWREV_8169,        ETHERMTU,
          RE_C_HWCSUM | RE_C_8169 },

        { RE_HWREV_8110S,       RE_MTU_6K,
          RE_C_HWCSUM | RE_C_8169 },

        { RE_HWREV_8169S,       RE_MTU_6K,
          RE_C_HWCSUM | RE_C_8169 },

        { RE_HWREV_8169SB,      RE_MTU_6K,
          RE_C_HWCSUM | RE_C_PHYPMGT | RE_C_8169 },

        { RE_HWREV_8169SC,      RE_MTU_6K,
          RE_C_HWCSUM | RE_C_PHYPMGT | RE_C_8169 },

        { RE_HWREV_8168B1,      RE_MTU_6K,
          RE_C_HWIM | RE_C_HWCSUM | RE_C_PHYPMGT },

        { RE_HWREV_8168B2,      RE_MTU_6K,
          RE_C_HWIM | RE_C_HWCSUM | RE_C_PHYPMGT | RE_C_AUTOPAD },

        { RE_HWREV_8168C,       RE_MTU_6K,
          RE_C_HWIM | RE_C_HWCSUM | RE_C_MAC2 | RE_C_PHYPMGT |
          RE_C_AUTOPAD | RE_C_CONTIGRX | RE_C_STOP_RXTX },

        { RE_HWREV_8168CP,      RE_MTU_6K,
          RE_C_HWIM | RE_C_HWCSUM | RE_C_MAC2 | RE_C_PHYPMGT |
          RE_C_AUTOPAD | RE_C_CONTIGRX | RE_C_STOP_RXTX },

        { RE_HWREV_8168D,       RE_MTU_9K,
          RE_C_HWIM | RE_C_HWCSUM | RE_C_MAC2 | RE_C_PHYPMGT |
          RE_C_AUTOPAD | RE_C_CONTIGRX | RE_C_STOP_RXTX },

        { RE_HWREV_8168DP,      RE_MTU_9K,
          RE_C_HWIM | RE_C_HWCSUM | RE_C_MAC2 | RE_C_PHYPMGT |
          RE_C_AUTOPAD | RE_C_CONTIGRX | RE_C_STOP_RXTX },

        { RE_HWREV_8168E,       RE_MTU_9K,
          RE_C_HWIM | RE_C_HWCSUM | RE_C_MAC2 | RE_C_PHYPMGT |
          RE_C_AUTOPAD | RE_C_CONTIGRX | RE_C_STOP_RXTX },

        { RE_HWREV_8168F,       RE_MTU_9K,
          RE_C_HWIM | RE_C_HWCSUM | RE_C_MAC2 | RE_C_PHYPMGT |
          RE_C_AUTOPAD | RE_C_CONTIGRX | RE_C_STOP_RXTX },

        { RE_HWREV_8111F,       RE_MTU_9K,
          RE_C_HWIM | RE_C_HWCSUM | RE_C_MAC2 | RE_C_PHYPMGT |
          RE_C_AUTOPAD | RE_C_CONTIGRX | RE_C_STOP_RXTX },

        { RE_HWREV_8411,        ETHERMTU,
          RE_C_HWIM | RE_C_HWCSUM | RE_C_MAC2 | RE_C_PHYPMGT |
          RE_C_AUTOPAD | RE_C_CONTIGRX | RE_C_STOP_RXTX },

        { RE_HWREV_8168G,       ETHERMTU,
          RE_C_HWIM | RE_C_HWCSUM | RE_C_MAC2 | RE_C_PHYPMGT |
          RE_C_AUTOPAD | RE_C_CONTIGRX | RE_C_STOP_RXTX },

        { RE_HWREV_8168EP,      ETHERMTU,
          RE_C_HWIM | RE_C_HWCSUM | RE_C_MAC2 | RE_C_PHYPMGT |
          RE_C_AUTOPAD | RE_C_CONTIGRX | RE_C_STOP_RXTX },

        { RE_HWREV_8168GU,      ETHERMTU,
          RE_C_HWIM | RE_C_HWCSUM | RE_C_MAC2 | RE_C_PHYPMGT |
          RE_C_AUTOPAD | RE_C_CONTIGRX | RE_C_STOP_RXTX },

        { RE_HWREV_8168H,       ETHERMTU,
          RE_C_HWIM | RE_C_HWCSUM | RE_C_MAC2 | RE_C_PHYPMGT |
          RE_C_AUTOPAD | RE_C_CONTIGRX | RE_C_STOP_RXTX },

        { RE_HWREV_8411B,       ETHERMTU,
          RE_C_HWIM | RE_C_HWCSUM | RE_C_MAC2 | RE_C_PHYPMGT |
          RE_C_AUTOPAD | RE_C_CONTIGRX | RE_C_STOP_RXTX },

        { RE_HWREV_8100E,       ETHERMTU,
          RE_C_HWCSUM | RE_C_FASTE },

        { RE_HWREV_8101E,       ETHERMTU,
          RE_C_HWCSUM | RE_C_FASTE },

        { RE_HWREV_8102E,       ETHERMTU,
          RE_C_HWCSUM | RE_C_MAC2 | RE_C_AUTOPAD | RE_C_STOP_RXTX |
          RE_C_FASTE },

        { RE_HWREV_8102EL,      ETHERMTU,
          RE_C_HWCSUM | RE_C_MAC2 | RE_C_AUTOPAD | RE_C_STOP_RXTX |
          RE_C_FASTE },

        { RE_HWREV_8105E,       ETHERMTU,
          RE_C_HWCSUM | RE_C_MAC2 | RE_C_PHYPMGT | RE_C_AUTOPAD |
          RE_C_STOP_RXTX | RE_C_FASTE },

        { RE_HWREV_8401E,       ETHERMTU,
          RE_C_HWCSUM | RE_C_MAC2 | RE_C_PHYPMGT | RE_C_AUTOPAD |
          RE_C_STOP_RXTX | RE_C_FASTE },

        { RE_HWREV_8402,        ETHERMTU,
          RE_C_HWCSUM | RE_C_MAC2 | RE_C_PHYPMGT | RE_C_AUTOPAD |
          RE_C_STOP_RXTX | RE_C_FASTE },

        { RE_HWREV_8106E,       ETHERMTU,
          RE_C_HWCSUM | RE_C_MAC2 | RE_C_PHYPMGT | RE_C_AUTOPAD |
          RE_C_STOP_RXTX | RE_C_FASTE },

        { RE_HWREV_NULL, 0, 0 }
};

static int      re_probe(device_t);
static int      re_attach(device_t);
static int      re_detach(device_t);
static int      re_suspend(device_t);
static int      re_resume(device_t);
static void     re_shutdown(device_t);

static int      re_allocmem(device_t);
static void     re_freemem(device_t);
static void     re_freebufmem(struct re_softc *, int, int);
static int      re_encap(struct re_softc *, struct mbuf **, int *);
static int      re_newbuf_std(struct re_softc *, int, int);
static int      re_newbuf_jumbo(struct re_softc *, int, int);
static void     re_setup_rxdesc(struct re_softc *, int);
static int      re_rx_list_init(struct re_softc *);
static int      re_tx_list_init(struct re_softc *);
static int      re_rxeof(struct re_softc *);
static int      re_txeof(struct re_softc *);
static int      re_tx_collect(struct re_softc *);
static void     re_intr(void *);
static void     re_tick(void *);
static void     re_tick_serialized(void *);

static void     re_start(struct ifnet *, struct ifaltq_subque *);
static int      re_ioctl(struct ifnet *, u_long, caddr_t, struct ucred *);
static void     re_init(void *);
static void     re_stop(struct re_softc *);
static void     re_watchdog(struct ifnet *);
static int      re_ifmedia_upd(struct ifnet *);
static void     re_ifmedia_sts(struct ifnet *, struct ifmediareq *);

static void     re_eeprom_putbyte(struct re_softc *, int);
static void     re_eeprom_getword(struct re_softc *, int, u_int16_t *);
static void     re_read_eeprom(struct re_softc *, caddr_t, int, int);
static void     re_get_eewidth(struct re_softc *);

static int      re_gmii_readreg(device_t, int, int);
static int      re_gmii_writereg(device_t, int, int, int);

static int      re_miibus_readreg(device_t, int, int);
static int      re_miibus_writereg(device_t, int, int, int);
static void     re_miibus_statchg(device_t);

static void     re_setmulti(struct re_softc *);
static void     re_reset(struct re_softc *, int);
static void     re_get_eaddr(struct re_softc *, uint8_t *);

static void     re_setup_hw_im(struct re_softc *);
static void     re_setup_sim_im(struct re_softc *);
static void     re_disable_hw_im(struct re_softc *);
static void     re_disable_sim_im(struct re_softc *);
static void     re_config_imtype(struct re_softc *, int);
static void     re_setup_intr(struct re_softc *, int, int);

static int      re_sysctl_hwtime(SYSCTL_HANDLER_ARGS, int *);
static int      re_sysctl_rxtime(SYSCTL_HANDLER_ARGS);
static int      re_sysctl_txtime(SYSCTL_HANDLER_ARGS);
static int      re_sysctl_simtime(SYSCTL_HANDLER_ARGS);
static int      re_sysctl_imtype(SYSCTL_HANDLER_ARGS);

static int      re_jpool_alloc(struct re_softc *);
static void     re_jpool_free(struct re_softc *);
static struct re_jbuf *re_jbuf_alloc(struct re_softc *);
static void     re_jbuf_free(void *);
static void     re_jbuf_ref(void *);

#ifdef RE_DIAG
static int      re_diag(struct re_softc *);
#endif

#ifdef IFPOLL_ENABLE
static void     re_npoll(struct ifnet *, struct ifpoll_info *);
static void     re_npoll_compat(struct ifnet *, void *, int);
#endif

static device_method_t re_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         re_probe),
        DEVMETHOD(device_attach,        re_attach),
        DEVMETHOD(device_detach,        re_detach),
        DEVMETHOD(device_suspend,       re_suspend),
        DEVMETHOD(device_resume,        re_resume),
        DEVMETHOD(device_shutdown,      re_shutdown),

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

        /* MII interface */
        DEVMETHOD(miibus_readreg,       re_miibus_readreg),
        DEVMETHOD(miibus_writereg,      re_miibus_writereg),
        DEVMETHOD(miibus_statchg,       re_miibus_statchg),

        DEVMETHOD_END
};

static driver_t re_driver = {
        "re",
        re_methods,
        sizeof(struct re_softc)
};

static devclass_t re_devclass;

DECLARE_DUMMY_MODULE(if_re);
MODULE_DEPEND(if_re, miibus, 1, 1, 1);
DRIVER_MODULE(if_re, pci, re_driver, re_devclass, NULL, NULL);
DRIVER_MODULE(if_re, cardbus, re_driver, re_devclass, NULL, NULL);
DRIVER_MODULE(miibus, re, miibus_driver, miibus_devclass, NULL, NULL);

static int      re_rx_desc_count = RE_RX_DESC_CNT_DEF;
static int      re_tx_desc_count = RE_TX_DESC_CNT_DEF;
static int      re_msi_enable = 0;

TUNABLE_INT("hw.re.rx_desc_count", &re_rx_desc_count);
TUNABLE_INT("hw.re.tx_desc_count", &re_tx_desc_count);
TUNABLE_INT("hw.re.msi.enable", &re_msi_enable);

#define EE_SET(x)       \
        CSR_WRITE_1(sc, RE_EECMD, CSR_READ_1(sc, RE_EECMD) | (x))

#define EE_CLR(x)       \
        CSR_WRITE_1(sc, RE_EECMD, CSR_READ_1(sc, RE_EECMD) & ~(x))

static __inline void
re_free_rxchain(struct re_softc *sc)
{
        if (sc->re_head != NULL) {
                m_freem(sc->re_head);
                sc->re_head = sc->re_tail = NULL;
        }
}

/*
 * Send a read command and address to the EEPROM, check for ACK.
 */
static void
re_eeprom_putbyte(struct re_softc *sc, int addr)
{
        int d, i;

        d = addr | (RE_9346_READ << sc->re_eewidth);

        /*
         * Feed in each bit and strobe the clock.
         */
        for (i = 1 << (sc->re_eewidth + 3); i; i >>= 1) {
                if (d & i)
                        EE_SET(RE_EE_DATAIN);
                else
                        EE_CLR(RE_EE_DATAIN);
                DELAY(100);
                EE_SET(RE_EE_CLK);
                DELAY(150);
                EE_CLR(RE_EE_CLK);
                DELAY(100);
        }
}

/*
 * Read a word of data stored in the EEPROM at address 'addr.'
 */
static void
re_eeprom_getword(struct re_softc *sc, int addr, uint16_t *dest)
{
        int i;
        uint16_t word = 0;

        /*
         * Send address of word we want to read.
         */
        re_eeprom_putbyte(sc, addr);

        /*
         * Start reading bits from EEPROM.
         */
        for (i = 0x8000; i != 0; i >>= 1) {
                EE_SET(RE_EE_CLK);
                DELAY(100);
                if (CSR_READ_1(sc, RE_EECMD) & RE_EE_DATAOUT)
                        word |= i;
                EE_CLR(RE_EE_CLK);
                DELAY(100);
        }

        *dest = word;
}

/*
 * Read a sequence of words from the EEPROM.
 */
static void
re_read_eeprom(struct re_softc *sc, caddr_t dest, int off, int cnt)
{
        int i;
        uint16_t word = 0, *ptr;

        CSR_SETBIT_1(sc, RE_EECMD, RE_EEMODE_PROGRAM);
        DELAY(100);

        for (i = 0; i < cnt; i++) {
                CSR_SETBIT_1(sc, RE_EECMD, RE_EE_SEL);
                re_eeprom_getword(sc, off + i, &word);
                CSR_CLRBIT_1(sc, RE_EECMD, RE_EE_SEL);
                ptr = (uint16_t *)(dest + (i * 2));
                *ptr = word;
        }

        CSR_CLRBIT_1(sc, RE_EECMD, RE_EEMODE_PROGRAM);
}

static void
re_get_eewidth(struct re_softc *sc)
{
        uint16_t re_did = 0;

        sc->re_eewidth = 6;
        re_read_eeprom(sc, (caddr_t)&re_did, 0, 1);
        if (re_did != 0x8129)
                sc->re_eewidth = 8;
}

static int
re_gmii_readreg(device_t dev, int phy, int reg)
{
        struct re_softc *sc = device_get_softc(dev);
        u_int32_t rval;
        int i;

        if (phy != 1)
                return(0);

        /* Let the rgephy driver read the GMEDIASTAT register */

        if (reg == RE_GMEDIASTAT)
                return(CSR_READ_1(sc, RE_GMEDIASTAT));

        CSR_WRITE_4(sc, RE_PHYAR, reg << 16);
        DELAY(1000);

        for (i = 0; i < RE_TIMEOUT; i++) {
                rval = CSR_READ_4(sc, RE_PHYAR);
                if (rval & RE_PHYAR_BUSY)
                        break;
                DELAY(100);
        }

        if (i == RE_TIMEOUT) {
                device_printf(dev, "PHY read failed\n");
                return(0);
        }

        return(rval & RE_PHYAR_PHYDATA);
}

static int
re_gmii_writereg(device_t dev, int phy, int reg, int data)
{
        struct re_softc *sc = device_get_softc(dev);
        uint32_t rval;
        int i;

        CSR_WRITE_4(sc, RE_PHYAR,
                    (reg << 16) | (data & RE_PHYAR_PHYDATA) | RE_PHYAR_BUSY);
        DELAY(1000);

        for (i = 0; i < RE_TIMEOUT; i++) {
                rval = CSR_READ_4(sc, RE_PHYAR);
                if ((rval & RE_PHYAR_BUSY) == 0)
                        break;
                DELAY(100);
        }

        if (i == RE_TIMEOUT)
                device_printf(dev, "PHY write failed\n");

        return(0);
}

static int
re_miibus_readreg(device_t dev, int phy, int reg)
{
        struct re_softc *sc = device_get_softc(dev);
        uint16_t rval = 0;
        uint16_t re8139_reg = 0;

        if (!RE_IS_8139CP(sc)) {
                rval = re_gmii_readreg(dev, phy, reg);
                return(rval);
        }

        /* Pretend the internal PHY is only at address 0 */
        if (phy)
                return(0);

        switch(reg) {
        case MII_BMCR:
                re8139_reg = RE_BMCR;
                break;
        case MII_BMSR:
                re8139_reg = RE_BMSR;
                break;
        case MII_ANAR:
                re8139_reg = RE_ANAR;
                break;
        case MII_ANER:
                re8139_reg = RE_ANER;
                break;
        case MII_ANLPAR:
                re8139_reg = RE_LPAR;
                break;
        case MII_PHYIDR1:
        case MII_PHYIDR2:
                return(0);
        /*
         * Allow the rlphy driver to read the media status
         * register. If we have a link partner which does not
         * support NWAY, this is the register which will tell
         * us the results of parallel detection.
         */
        case RE_MEDIASTAT:
                return(CSR_READ_1(sc, RE_MEDIASTAT));
        default:
                device_printf(dev, "bad phy register\n");
                return(0);
        }
        rval = CSR_READ_2(sc, re8139_reg);
        if (re8139_reg == RE_BMCR) {
                /* 8139C+ has different bit layout. */
                rval &= ~(BMCR_LOOP | BMCR_ISO);
        }
        return(rval);
}

static int
re_miibus_writereg(device_t dev, int phy, int reg, int data)
{
        struct re_softc *sc= device_get_softc(dev);
        u_int16_t re8139_reg = 0;

        if (!RE_IS_8139CP(sc))
                return(re_gmii_writereg(dev, phy, reg, data));

        /* Pretend the internal PHY is only at address 0 */
        if (phy)
                return(0);

        switch(reg) {
        case MII_BMCR:
                re8139_reg = RE_BMCR;
                /* 8139C+ has different bit layout. */
                data &= ~(BMCR_LOOP | BMCR_ISO);
                break;
        case MII_BMSR:
                re8139_reg = RE_BMSR;
                break;
        case MII_ANAR:
                re8139_reg = RE_ANAR;
                break;
        case MII_ANER:
                re8139_reg = RE_ANER;
                break;
        case MII_ANLPAR:
                re8139_reg = RE_LPAR;
                break;
        case MII_PHYIDR1:
        case MII_PHYIDR2:
                return(0);
        default:
                device_printf(dev, "bad phy register\n");
                return(0);
        }
        CSR_WRITE_2(sc, re8139_reg, data);
        return(0);
}

static void
re_miibus_statchg(device_t dev)
{
}

/*
 * Program the 64-bit multicast hash filter.
 */
static void
re_setmulti(struct re_softc *sc)
{
        struct ifnet *ifp = &sc->arpcom.ac_if;
        int h = 0;
        uint32_t hashes[2] = { 0, 0 };
        struct ifmultiaddr *ifma;
        uint32_t rxfilt;
        int mcnt = 0;

        rxfilt = CSR_READ_4(sc, RE_RXCFG);

        /* Set the individual bit to receive frames for this host only. */
        rxfilt |= RE_RXCFG_RX_INDIV;
        /* Set capture broadcast bit to capture broadcast frames. */
        rxfilt |= RE_RXCFG_RX_BROAD;

        rxfilt &= ~(RE_RXCFG_RX_ALLPHYS | RE_RXCFG_RX_MULTI);
        if ((ifp->if_flags & IFF_ALLMULTI) || (ifp->if_flags & IFF_PROMISC)) {
                rxfilt |= RE_RXCFG_RX_MULTI;

                /* If we want promiscuous mode, set the allframes bit. */
                if (ifp->if_flags & IFF_PROMISC)
                        rxfilt |= RE_RXCFG_RX_ALLPHYS;

                CSR_WRITE_4(sc, RE_RXCFG, rxfilt);
                CSR_WRITE_4(sc, RE_MAR0, 0xFFFFFFFF);
                CSR_WRITE_4(sc, RE_MAR4, 0xFFFFFFFF);
                return;
        }

        /* first, zot all the existing hash bits */
        CSR_WRITE_4(sc, RE_MAR0, 0);
        CSR_WRITE_4(sc, RE_MAR4, 0);

        /* now program new ones */
        TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
                if (ifma->ifma_addr->sa_family != AF_LINK)
                        continue;
                h = ether_crc32_be(LLADDR((struct sockaddr_dl *)
                    ifma->ifma_addr), ETHER_ADDR_LEN) >> 26;
                if (h < 32)
                        hashes[0] |= (1 << h);
                else
                        hashes[1] |= (1 << (h - 32));
                mcnt++;
        }

        if (mcnt)
                rxfilt |= RE_RXCFG_RX_MULTI;
        else
                rxfilt &= ~RE_RXCFG_RX_MULTI;

        CSR_WRITE_4(sc, RE_RXCFG, rxfilt);

        /*
         * For some unfathomable reason, RealTek decided to reverse
         * the order of the multicast hash registers in the PCI Express
         * parts. This means we have to write the hash pattern in reverse
         * order for those devices.
         */
        if (sc->re_caps & RE_C_PCIE) {
                CSR_WRITE_4(sc, RE_MAR0, bswap32(hashes[1]));
                CSR_WRITE_4(sc, RE_MAR4, bswap32(hashes[0]));
        } else {
                CSR_WRITE_4(sc, RE_MAR0, hashes[0]);
                CSR_WRITE_4(sc, RE_MAR4, hashes[1]);
        }
}

static void
re_reset(struct re_softc *sc, int running)
{
        int i;

        if ((sc->re_caps & RE_C_STOP_RXTX) && running) {
                CSR_WRITE_1(sc, RE_COMMAND,
                            RE_CMD_STOPREQ | RE_CMD_TX_ENB | RE_CMD_RX_ENB);
                DELAY(100);
        }

        CSR_WRITE_1(sc, RE_COMMAND, RE_CMD_RESET);

        for (i = 0; i < RE_TIMEOUT; i++) {
                DELAY(10);
                if ((CSR_READ_1(sc, RE_COMMAND) & RE_CMD_RESET) == 0)
                        break;
        }
        if (i == RE_TIMEOUT)
                if_printf(&sc->arpcom.ac_if, "reset never completed!\n");
}

#ifdef RE_DIAG
/*
 * The following routine is designed to test for a defect on some
 * 32-bit 8169 cards. Some of these NICs have the REQ64# and ACK64#
 * lines connected to the bus, however for a 32-bit only card, they
 * should be pulled high. The result of this defect is that the
 * NIC will not work right if you plug it into a 64-bit slot: DMA
 * operations will be done with 64-bit transfers, which will fail
 * because the 64-bit data lines aren't connected.
 *
 * There's no way to work around this (short of talking a soldering
 * iron to the board), however we can detect it. The method we use
 * here is to put the NIC into digital loopback mode, set the receiver
 * to promiscuous mode, and then try to send a frame. We then compare
 * the frame data we sent to what was received. If the data matches,
 * then the NIC is working correctly, otherwise we know the user has
 * a defective NIC which has been mistakenly plugged into a 64-bit PCI
 * slot. In the latter case, there's no way the NIC can work correctly,
 * so we print out a message on the console and abort the device attach.
 */

static int
re_diag(struct re_softc *sc)
{
        struct ifnet *ifp = &sc->arpcom.ac_if;
        struct mbuf *m0;
        struct ether_header *eh;
        struct re_desc *cur_rx;
        uint16_t status;
        int total_len, i, error = 0, phyaddr;
        uint8_t dst[ETHER_ADDR_LEN] = { 0x00, 'h', 'e', 'l', 'l', 'o' };
        uint8_t src[ETHER_ADDR_LEN] = { 0x00, 'w', 'o', 'r', 'l', 'd' };
        char ethstr[2][ETHER_ADDRSTRLEN + 1];

        /* Allocate a single mbuf */

        MGETHDR(m0, M_NOWAIT, MT_DATA);
        if (m0 == NULL)
                return(ENOBUFS);

        /*
         * Initialize the NIC in test mode. This sets the chip up
         * so that it can send and receive frames, but performs the
         * following special functions:
         * - Puts receiver in promiscuous mode
         * - Enables digital loopback mode
         * - Leaves interrupts turned off
         */

        ifp->if_flags |= IFF_PROMISC;
        sc->re_flags |= RE_F_TESTMODE;
        re_init(sc);
        sc->re_flags |= RE_F_LINKED;
        if (!RE_IS_8139CP(sc))
                phyaddr = 1;
        else
                phyaddr = 0;

        re_miibus_writereg(sc->re_dev, phyaddr, MII_BMCR, BMCR_RESET);
        for (i = 0; i < RE_TIMEOUT; i++) {
                status = re_miibus_readreg(sc->re_dev, phyaddr, MII_BMCR);
                if (!(status & BMCR_RESET))
                        break;
        }

        re_miibus_writereg(sc->re_dev, phyaddr, MII_BMCR, BMCR_LOOP);
        CSR_WRITE_2(sc, RE_ISR, RE_INTRS_DIAG);

        DELAY(100000);

        /* Put some data in the mbuf */

        eh = mtod(m0, struct ether_header *);
        bcopy (dst, eh->ether_dhost, ETHER_ADDR_LEN);
        bcopy (src, eh->ether_shost, ETHER_ADDR_LEN);
        eh->ether_type = htons(ETHERTYPE_IP);
        m0->m_pkthdr.len = m0->m_len = ETHER_MIN_LEN - ETHER_CRC_LEN;

        /*
         * Queue the packet, start transmission.
         * Note: ifq_handoff() ultimately calls re_start() for us.
         */

        CSR_WRITE_2(sc, RE_ISR, 0xFFFF);
        error = ifq_handoff(ifp, m0, NULL);
        if (error) {
                m0 = NULL;
                goto done;
        }
        m0 = NULL;

        /* Wait for it to propagate through the chip */

        DELAY(100000);
        for (i = 0; i < RE_TIMEOUT; i++) {
                status = CSR_READ_2(sc, RE_ISR);
                CSR_WRITE_2(sc, RE_ISR, status);
                if ((status & (RE_ISR_TIMEOUT_EXPIRED|RE_ISR_RX_OK)) ==
                    (RE_ISR_TIMEOUT_EXPIRED|RE_ISR_RX_OK))
                        break;
                DELAY(10);
        }

        if (i == RE_TIMEOUT) {
                if_printf(ifp, "diagnostic failed to receive packet "
                          "in loopback mode\n");
                error = EIO;
                goto done;
        }

        /*
         * The packet should have been dumped into the first
         * entry in the RX DMA ring. Grab it from there.
         */

        bus_dmamap_sync(sc->re_ldata.re_rx_mtag, sc->re_ldata.re_rx_dmamap[0],
                        BUS_DMASYNC_POSTREAD);
        bus_dmamap_unload(sc->re_ldata.re_rx_mtag,
                          sc->re_ldata.re_rx_dmamap[0]);

        m0 = sc->re_ldata.re_rx_mbuf[0];
        sc->re_ldata.re_rx_mbuf[0] = NULL;
        eh = mtod(m0, struct ether_header *);

        cur_rx = &sc->re_ldata.re_rx_list[0];
        total_len = RE_RXBYTES(cur_rx);

        if (total_len != ETHER_MIN_LEN) {
                if_printf(ifp, "diagnostic failed, received short packet\n");
                error = EIO;
                goto done;
        }

        /* Test that the received packet data matches what we sent. */

        if (bcmp(eh->ether_dhost, dst, ETHER_ADDR_LEN) ||
            bcmp(eh->ether_shost, &src, ETHER_ADDR_LEN) ||
            be16toh(eh->ether_type) != ETHERTYPE_IP) {
                if_printf(ifp, "WARNING, DMA FAILURE!\n");
                if_printf(ifp, "expected TX data: %s/%s/0x%x\n",
                    kether_ntoa(dst, ethstr[0]), kether_ntoa(src, ethstr[1]), ETHERTYPE_IP);
                if_printf(ifp, "received RX data: %s/%s/0x%x\n",
                    kether_ntoa(eh->ether_dhost, ethstr[0]),
                    kether_ntoa(eh->ether_shost, ethstr[1]),
                    ntohs(eh->ether_type));
                if_printf(ifp, "You may have a defective 32-bit NIC plugged "
                    "into a 64-bit PCI slot.\n");
                if_printf(ifp, "Please re-install the NIC in a 32-bit slot "
                    "for proper operation.\n");
                if_printf(ifp, "Read the re(4) man page for more details.\n");
                error = EIO;
        }

done:
        /* Turn interface off, release resources */

        sc->re_flags &= ~(RE_F_LINKED | RE_F_TESTMODE);
        ifp->if_flags &= ~IFF_PROMISC;
        re_stop(sc);
        if (m0 != NULL)
                m_freem(m0);

        return (error);
}
#endif  /* RE_DIAG */

/*
 * Probe for a RealTek 8139C+/8169/8110 chip. Check the PCI vendor and device
 * IDs against our list and return a device name if we find a match.
 */
static int
re_probe(device_t dev)
{
        const struct re_type *t;
        const struct re_hwrev *hw_rev;
        struct re_softc *sc;
        int rid;
        uint32_t hwrev, macmode, txcfg;
        uint16_t vendor, product;

        vendor = pci_get_vendor(dev);
        product = pci_get_device(dev);

        /*
         * Only attach to rev.3 of the Linksys EG1032 adapter.
         * Rev.2 is supported by sk(4).
         */
        if (vendor == PCI_VENDOR_LINKSYS &&
            product == PCI_PRODUCT_LINKSYS_EG1032 &&
            pci_get_subdevice(dev) != PCI_SUBDEVICE_LINKSYS_EG1032_REV3)
                return ENXIO;

        if (vendor == PCI_VENDOR_REALTEK &&
            product == PCI_PRODUCT_REALTEK_RT8139 &&
            pci_get_revid(dev) != PCI_REVID_REALTEK_RT8139CP) {
                /* Poor 8139 */
                return ENXIO;
        }

        for (t = re_devs; t->re_name != NULL; t++) {
                if (product == t->re_did && vendor == t->re_vid)
                        break;
        }

        /*
         * Check if we found a RealTek device.
         */
        if (t->re_name == NULL)
                return ENXIO;

        /*
         * Temporarily map the I/O space so we can read the chip ID register.
         */
        sc = kmalloc(sizeof(*sc), M_TEMP, M_WAITOK | M_ZERO);
        rid = RE_PCI_LOIO;
        sc->re_res = bus_alloc_resource_any(dev, SYS_RES_IOPORT, &rid,
                                            RF_ACTIVE);
        if (sc->re_res == NULL) {
                device_printf(dev, "couldn't map ports/memory\n");
                kfree(sc, M_TEMP);
                return ENXIO;
        }

        sc->re_btag = rman_get_bustag(sc->re_res);
        sc->re_bhandle = rman_get_bushandle(sc->re_res);

        txcfg = CSR_READ_4(sc, RE_TXCFG);
        hwrev = txcfg & RE_TXCFG_HWREV;
        macmode = txcfg & RE_TXCFG_MACMODE;
        bus_release_resource(dev, SYS_RES_IOPORT, RE_PCI_LOIO, sc->re_res);
        kfree(sc, M_TEMP);

        /*
         * and continue matching for the specific chip...
         */
        for (hw_rev = re_hwrevs; hw_rev->re_hwrev != RE_HWREV_NULL; hw_rev++) {
                if (hw_rev->re_hwrev == hwrev) {
                        sc = device_get_softc(dev);

                        sc->re_hwrev = hw_rev->re_hwrev;
                        sc->re_caps = hw_rev->re_caps;
                        sc->re_maxmtu = hw_rev->re_maxmtu;

                        /*
                         * Apply chip property fixup
                         */
                        switch (sc->re_hwrev) {
                        case RE_HWREV_8168GU:
                                if (vendor == PCI_VENDOR_REALTEK &&
                                    product == PCI_PRODUCT_REALTEK_RT8101E) {
                                        /* 8106EUS */
                                        sc->re_caps = RE_C_HWCSUM | RE_C_MAC2 |
                                            RE_C_PHYPMGT | RE_C_AUTOPAD |
                                            RE_C_STOP_RXTX | RE_C_FASTE;
                                        sc->re_maxmtu = ETHERMTU;
                                        device_printf(dev, "8106EUS fixup\n");
                                } else {
                                        /* 8168GU */
                                        goto ee_eaddr1;
                                }
                                break;

                        case RE_HWREV_8168E:
                                if (vendor == PCI_VENDOR_REALTEK &&
                                    product == PCI_PRODUCT_REALTEK_RT8101E) {
                                        /* 8105E */
                                        sc->re_caps = RE_C_HWCSUM | RE_C_MAC2 |
                                            RE_C_PHYPMGT | RE_C_AUTOPAD |
                                            RE_C_STOP_RXTX | RE_C_FASTE;
                                        sc->re_maxmtu = ETHERMTU;
                                        device_printf(dev, "8105E fixup\n");
                                        goto ee_eaddr0;
                                }
                                /* 8168E */
                                break;

                        case RE_HWREV_8101E:
                        case RE_HWREV_8102E:
                        case RE_HWREV_8102EL:
                        case RE_HWREV_8401E:
                        case RE_HWREV_8105E:
                        case RE_HWREV_8106E:
ee_eaddr0:
                                sc->re_caps |= RE_C_EE_EADDR;
                                sc->re_ee_eaddr = RE_EE_EADDR0;
                                break;

                        case RE_HWREV_8168F:
                        case RE_HWREV_8111F:
                        case RE_HWREV_8168G:
                                if (macmode == 0 ||
                                    macmode == 0x100000) {
                                        sc->re_caps |= RE_C_EE_EADDR;
                                        sc->re_ee_eaddr = RE_EE_EADDR1;
                                }
                                break;

                        case RE_HWREV_8411:
                        case RE_HWREV_8168EP:
                        case RE_HWREV_8168H:
                        case RE_HWREV_8411B:
ee_eaddr1:
                                sc->re_caps |= RE_C_EE_EADDR;
                                sc->re_ee_eaddr = RE_EE_EADDR1;
                                break;
                        }
                        if (pci_is_pcie(dev))
                                sc->re_caps |= RE_C_PCIE;

                        device_set_desc(dev, t->re_name);
                        return 0;
                }
        }
        device_printf(dev, "unknown hwrev 0x%08x, macmode 0x%08x\n",
            hwrev, macmode);

        return ENXIO;
}

static int
re_allocmem(device_t dev)
{
        struct re_softc *sc = device_get_softc(dev);
        bus_dmamem_t dmem;
        int error, i;

        /*
         * Allocate list data
         */
        sc->re_ldata.re_tx_mbuf =
        kmalloc(sc->re_tx_desc_cnt * sizeof(struct mbuf *),
                M_DEVBUF, M_ZERO | M_WAITOK);

        sc->re_ldata.re_rx_mbuf =
        kmalloc(sc->re_rx_desc_cnt * sizeof(struct mbuf *),
                M_DEVBUF, M_ZERO | M_WAITOK);

        sc->re_ldata.re_rx_paddr =
        kmalloc(sc->re_rx_desc_cnt * sizeof(bus_addr_t),
                M_DEVBUF, M_ZERO | M_WAITOK);

        sc->re_ldata.re_tx_dmamap =
        kmalloc(sc->re_tx_desc_cnt * sizeof(bus_dmamap_t),
                M_DEVBUF, M_ZERO | M_WAITOK);

        sc->re_ldata.re_rx_dmamap =
        kmalloc(sc->re_rx_desc_cnt * sizeof(bus_dmamap_t),
                M_DEVBUF, M_ZERO | M_WAITOK);

        /*
         * Allocate the parent bus DMA tag appropriate for PCI.
         */
        error = bus_dma_tag_create(NULL,        /* parent */
                        1, 0,                   /* alignment, boundary */
                        BUS_SPACE_MAXADDR,      /* lowaddr */
                        BUS_SPACE_MAXADDR,      /* highaddr */
                        NULL, NULL,             /* filter, filterarg */
                        BUS_SPACE_MAXSIZE_32BIT,/* maxsize */
                        0,                      /* nsegments */
                        BUS_SPACE_MAXSIZE_32BIT,/* maxsegsize */
                        0,                      /* flags */
                        &sc->re_parent_tag);
        if (error) {
                device_printf(dev, "could not allocate parent dma tag\n");
                return error;
        }

        /* Allocate TX descriptor list. */
        error = bus_dmamem_coherent(sc->re_parent_tag,
                        RE_RING_ALIGN, 0,
                        BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR,
                        RE_TX_LIST_SZ(sc), BUS_DMA_WAITOK | BUS_DMA_ZERO,
                        &dmem);
        if (error) {
                device_printf(dev, "could not allocate TX ring\n");
                return error;
        }
        sc->re_ldata.re_tx_list_tag = dmem.dmem_tag;
        sc->re_ldata.re_tx_list_map = dmem.dmem_map;
        sc->re_ldata.re_tx_list = dmem.dmem_addr;
        sc->re_ldata.re_tx_list_addr = dmem.dmem_busaddr;

        /* Allocate RX descriptor list. */
        error = bus_dmamem_coherent(sc->re_parent_tag,
                        RE_RING_ALIGN, 0,
                        BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR,
                        RE_RX_LIST_SZ(sc), BUS_DMA_WAITOK | BUS_DMA_ZERO,
                        &dmem);
        if (error) {
                device_printf(dev, "could not allocate RX ring\n");
                return error;
        }
        sc->re_ldata.re_rx_list_tag = dmem.dmem_tag;
        sc->re_ldata.re_rx_list_map = dmem.dmem_map;
        sc->re_ldata.re_rx_list = dmem.dmem_addr;
        sc->re_ldata.re_rx_list_addr = dmem.dmem_busaddr;

        /* Allocate maps for TX mbufs. */
        error = bus_dma_tag_create(sc->re_parent_tag,
                        1, 0,
                        BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR,
                        NULL, NULL,
                        RE_FRAMELEN_MAX, RE_MAXSEGS, MCLBYTES,
                        BUS_DMA_ALLOCNOW | BUS_DMA_WAITOK | BUS_DMA_ONEBPAGE,
                        &sc->re_ldata.re_tx_mtag);
        if (error) {
                device_printf(dev, "could not allocate TX buf dma tag\n");
                return(error);
        }

        /* Create DMA maps for TX buffers */
        for (i = 0; i < sc->re_tx_desc_cnt; i++) {
                error = bus_dmamap_create(sc->re_ldata.re_tx_mtag,
                                BUS_DMA_WAITOK | BUS_DMA_ONEBPAGE,
                                &sc->re_ldata.re_tx_dmamap[i]);
                if (error) {
                        device_printf(dev, "can't create DMA map for TX buf\n");
                        re_freebufmem(sc, i, 0);
                        return(error);
                }
        }

        /* Allocate maps for RX mbufs. */
        error = bus_dma_tag_create(sc->re_parent_tag,
                        RE_RXBUF_ALIGN, 0,
                        BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR,
                        NULL, NULL,
                        MCLBYTES, 1, MCLBYTES,
                        BUS_DMA_ALLOCNOW | BUS_DMA_WAITOK | BUS_DMA_ALIGNED,
                        &sc->re_ldata.re_rx_mtag);
        if (error) {
                device_printf(dev, "could not allocate RX buf dma tag\n");
                return(error);
        }

        /* Create spare DMA map for RX */
        error = bus_dmamap_create(sc->re_ldata.re_rx_mtag, BUS_DMA_WAITOK,
                        &sc->re_ldata.re_rx_spare);
        if (error) {
                device_printf(dev, "can't create spare DMA map for RX\n");
                bus_dma_tag_destroy(sc->re_ldata.re_rx_mtag);
                sc->re_ldata.re_rx_mtag = NULL;
                return error;
        }

        /* Create DMA maps for RX buffers */
        for (i = 0; i < sc->re_rx_desc_cnt; i++) {
                error = bus_dmamap_create(sc->re_ldata.re_rx_mtag,
                                BUS_DMA_WAITOK, &sc->re_ldata.re_rx_dmamap[i]);
                if (error) {
                        device_printf(dev, "can't create DMA map for RX buf\n");
                        re_freebufmem(sc, sc->re_tx_desc_cnt, i);
                        return(error);
                }
        }

        /* Create jumbo buffer pool for RX if required */
        if (sc->re_caps & RE_C_CONTIGRX) {
                error = re_jpool_alloc(sc);
                if (error) {
                        re_jpool_free(sc);
                        /* Disable jumbo frame support */
                        sc->re_maxmtu = ETHERMTU;
                }
        }
        return(0);
}

static void
re_freebufmem(struct re_softc *sc, int tx_cnt, int rx_cnt)
{
        int i;

        /* Destroy all the RX and TX buffer maps */
        if (sc->re_ldata.re_tx_mtag) {
                for (i = 0; i < tx_cnt; i++) {
                        bus_dmamap_destroy(sc->re_ldata.re_tx_mtag,
                                           sc->re_ldata.re_tx_dmamap[i]);
                }
                bus_dma_tag_destroy(sc->re_ldata.re_tx_mtag);
                sc->re_ldata.re_tx_mtag = NULL;
        }

        if (sc->re_ldata.re_rx_mtag) {
                for (i = 0; i < rx_cnt; i++) {
                        bus_dmamap_destroy(sc->re_ldata.re_rx_mtag,
                                           sc->re_ldata.re_rx_dmamap[i]);
                }
                bus_dmamap_destroy(sc->re_ldata.re_rx_mtag,
                                   sc->re_ldata.re_rx_spare);
                bus_dma_tag_destroy(sc->re_ldata.re_rx_mtag);
                sc->re_ldata.re_rx_mtag = NULL;
        }
}

static void
re_freemem(device_t dev)
{
        struct re_softc *sc = device_get_softc(dev);

        /* Unload and free the RX DMA ring memory and map */
        if (sc->re_ldata.re_rx_list_tag) {
                bus_dmamap_unload(sc->re_ldata.re_rx_list_tag,
                                  sc->re_ldata.re_rx_list_map);
                bus_dmamem_free(sc->re_ldata.re_rx_list_tag,
                                sc->re_ldata.re_rx_list,
                                sc->re_ldata.re_rx_list_map);
                bus_dma_tag_destroy(sc->re_ldata.re_rx_list_tag);
        }

        /* Unload and free the TX DMA ring memory and map */
        if (sc->re_ldata.re_tx_list_tag) {
                bus_dmamap_unload(sc->re_ldata.re_tx_list_tag,
                                  sc->re_ldata.re_tx_list_map);
                bus_dmamem_free(sc->re_ldata.re_tx_list_tag,
                                sc->re_ldata.re_tx_list,
                                sc->re_ldata.re_tx_list_map);
                bus_dma_tag_destroy(sc->re_ldata.re_tx_list_tag);
        }

        /* Free RX/TX buf DMA stuffs */
        re_freebufmem(sc, sc->re_tx_desc_cnt, sc->re_rx_desc_cnt);

        /* Unload and free the stats buffer and map */
        if (sc->re_ldata.re_stag) {
                bus_dmamap_unload(sc->re_ldata.re_stag, sc->re_ldata.re_smap);
                bus_dmamem_free(sc->re_ldata.re_stag,
                                sc->re_ldata.re_stats,
                                sc->re_ldata.re_smap);
                bus_dma_tag_destroy(sc->re_ldata.re_stag);
        }

        if (sc->re_caps & RE_C_CONTIGRX)
                re_jpool_free(sc);

        if (sc->re_parent_tag)
                bus_dma_tag_destroy(sc->re_parent_tag);

        if (sc->re_ldata.re_tx_mbuf != NULL)
                kfree(sc->re_ldata.re_tx_mbuf, M_DEVBUF);
        if (sc->re_ldata.re_rx_mbuf != NULL)
                kfree(sc->re_ldata.re_rx_mbuf, M_DEVBUF);
        if (sc->re_ldata.re_rx_paddr != NULL)
                kfree(sc->re_ldata.re_rx_paddr, M_DEVBUF);
        if (sc->re_ldata.re_tx_dmamap != NULL)
                kfree(sc->re_ldata.re_tx_dmamap, M_DEVBUF);
        if (sc->re_ldata.re_rx_dmamap != NULL)
                kfree(sc->re_ldata.re_rx_dmamap, M_DEVBUF);
}

/*
 * Attach the interface. Allocate softc structures, do ifmedia
 * setup and ethernet/BPF attach.
 */
static int
re_attach(device_t dev)
{
        struct re_softc *sc = device_get_softc(dev);
        struct ifnet *ifp;
        struct sysctl_ctx_list *ctx;
        struct sysctl_oid *tree;
        uint8_t eaddr[ETHER_ADDR_LEN];
        int error = 0, qlen, msi_enable;
        u_int irq_flags;

        callout_init_mp(&sc->re_timer);
        sc->re_dev = dev;

        if (RE_IS_8139CP(sc)) {
                sc->re_rx_desc_cnt = RE_RX_DESC_CNT_8139CP;
                sc->re_tx_desc_cnt = RE_TX_DESC_CNT_8139CP;
        } else {
                sc->re_rx_desc_cnt = re_rx_desc_count;
                if (sc->re_rx_desc_cnt > RE_RX_DESC_CNT_MAX)
                        sc->re_rx_desc_cnt = RE_RX_DESC_CNT_MAX;

                sc->re_tx_desc_cnt = re_tx_desc_count;
                if (sc->re_tx_desc_cnt > RE_TX_DESC_CNT_MAX)
                        sc->re_tx_desc_cnt = RE_TX_DESC_CNT_MAX;
        }

        qlen = RE_IFQ_MAXLEN;
        if (sc->re_tx_desc_cnt > qlen)
                qlen = sc->re_tx_desc_cnt;

        sc->re_rxbuf_size = MCLBYTES;
        sc->re_newbuf = re_newbuf_std;

        sc->re_tx_time = 5;             /* 125us */
        sc->re_rx_time = 2;             /* 50us */
        if (sc->re_caps & RE_C_PCIE)
                sc->re_sim_time = 75;   /* 75us */
        else
                sc->re_sim_time = 125;  /* 125us */
        if (!RE_IS_8139CP(sc)) {
                /* simulated interrupt moderation */
                sc->re_imtype = RE_IMTYPE_SIM;
        } else {
                sc->re_imtype = RE_IMTYPE_NONE;
        }
        re_config_imtype(sc, sc->re_imtype);

        ctx = device_get_sysctl_ctx(dev);
        tree = device_get_sysctl_tree(dev);
        SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
                       "rx_desc_count", CTLFLAG_RD, &sc->re_rx_desc_cnt,
                       0, "RX desc count");
        SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
                       "tx_desc_count", CTLFLAG_RD, &sc->re_tx_desc_cnt,
                       0, "TX desc count");
        SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO, "sim_time",
                        CTLTYPE_INT | CTLFLAG_RW,
                        sc, 0, re_sysctl_simtime, "I",
                        "Simulated interrupt moderation time (usec).");
        SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO, "imtype",
                        CTLTYPE_INT | CTLFLAG_RW,
                        sc, 0, re_sysctl_imtype, "I",
                        "Interrupt moderation type -- "
                        "0:disable, 1:simulated, "
                        "2:hardware(if supported)");
        if (sc->re_caps & RE_C_HWIM) {
                SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree),
                                OID_AUTO, "hw_rxtime",
                                CTLTYPE_INT | CTLFLAG_RW,
                                sc, 0, re_sysctl_rxtime, "I",
                                "Hardware interrupt moderation time "
                                "(unit: 25usec).");
                SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree),
                                OID_AUTO, "hw_txtime",
                                CTLTYPE_INT | CTLFLAG_RW,
                                sc, 0, re_sysctl_txtime, "I",
                                "Hardware interrupt moderation time "
                                "(unit: 25usec).");
        }

#ifndef BURN_BRIDGES
        /*
         * Handle power management nonsense.
         */

        if (pci_get_powerstate(dev) != PCI_POWERSTATE_D0) {
                uint32_t membase, irq;

                /* Save important PCI config data. */
                membase = pci_read_config(dev, RE_PCI_LOMEM, 4);
                irq = pci_read_config(dev, PCIR_INTLINE, 4);

                /* Reset the power state. */
                device_printf(dev, "chip is in D%d power mode "
                    "-- setting to D0\n", pci_get_powerstate(dev));

                pci_set_powerstate(dev, PCI_POWERSTATE_D0);

                /* Restore PCI config data. */
                pci_write_config(dev, RE_PCI_LOMEM, membase, 4);
                pci_write_config(dev, PCIR_INTLINE, irq, 4);
        }
#endif
        /*
         * Map control/status registers.
         */
        pci_enable_busmaster(dev);

        if (pci_is_pcie(dev)) {
                sc->re_res_rid = PCIR_BAR(2);
                sc->re_res_type = SYS_RES_MEMORY;
        } else {
                sc->re_res_rid = PCIR_BAR(0);
                sc->re_res_type = SYS_RES_IOPORT;
        }
        sc->re_res = bus_alloc_resource_any(dev, sc->re_res_type,
            &sc->re_res_rid, RF_ACTIVE);
        if (sc->re_res == NULL) {
                device_printf(dev, "couldn't map IO\n");
                error = ENXIO;
                goto fail;
        }

        sc->re_btag = rman_get_bustag(sc->re_res);
        sc->re_bhandle = rman_get_bushandle(sc->re_res);

        /*
         * Allocate interrupt
         */
        if (pci_is_pcie(dev))
                msi_enable = re_msi_enable;
        else
                msi_enable = 0;
        sc->re_irq_type = pci_alloc_1intr(dev, msi_enable,
            &sc->re_irq_rid, &irq_flags);

        sc->re_irq = bus_alloc_resource_any(dev, SYS_RES_IRQ, &sc->re_irq_rid,
                                            irq_flags);
        if (sc->re_irq == NULL) {
                device_printf(dev, "couldn't map interrupt\n");
                error = ENXIO;
                goto fail;
        }

        /* Reset the adapter. */
        re_reset(sc, 0);

        if (RE_IS_8139CP(sc)) {
                sc->re_bus_speed = 33; /* XXX */
        } else if (sc->re_caps & RE_C_PCIE) {
                sc->re_bus_speed = 125;
        } else {
                uint8_t cfg2;

                cfg2 = CSR_READ_1(sc, RE_CFG2);
                switch (cfg2 & RE_CFG2_PCICLK_MASK) {
                case RE_CFG2_PCICLK_33MHZ:
                        sc->re_bus_speed = 33;
                        break;
                case RE_CFG2_PCICLK_66MHZ:
                        sc->re_bus_speed = 66;
                        break;
                default:
                        device_printf(dev, "unknown bus speed, assume 33MHz\n");
                        sc->re_bus_speed = 33;
                        break;
                }
                if (cfg2 & RE_CFG2_PCI64)
                        sc->re_caps |= RE_C_PCI64;
        }
        device_printf(dev, "Hardware rev. 0x%08x; PCI%s %dMHz\n",
                      sc->re_hwrev,
                      (sc->re_caps & RE_C_PCIE) ?
                      "-E" : ((sc->re_caps & RE_C_PCI64) ? "64" : "32"),
                      sc->re_bus_speed);

        /*
         * NOTE:
         * DO NOT try to adjust config1 and config5 which was spotted in
         * Realtek's Linux drivers.  It will _permanently_ damage certain
         * cards EEPROM, e.g. one of my 8168B (0x38000000) card ...
         */

        re_get_eaddr(sc, eaddr);

        if (!RE_IS_8139CP(sc)) {
                /* Set RX length mask */
                sc->re_rxlenmask = RE_RDESC_STAT_GFRAGLEN;
                sc->re_txstart = RE_GTXSTART;
        } else {
                /* Set RX length mask */
                sc->re_rxlenmask = RE_RDESC_STAT_FRAGLEN;
                sc->re_txstart = RE_TXSTART;
        }

        /* Allocate DMA stuffs */
        error = re_allocmem(dev);
        if (error)
                goto fail;

        /*
         * Apply some magic PCI settings from Realtek ...
         */
        if (RE_IS_8169(sc)) {
                CSR_WRITE_1(sc, 0x82, 1);
                pci_write_config(dev, PCIR_CACHELNSZ, 0x8, 1);
        }
        pci_write_config(dev, PCIR_LATTIMER, 0x40, 1);

        if (sc->re_caps & RE_C_MAC2) {
                /*
                 * Following part is extracted from Realtek BSD driver v176.
                 * However, this does _not_ make much/any sense:
                 * 8168C's PCI Express device control is located at 0x78,
                 * so the reading from 0x79 (higher part of 0x78) and setting
                 * the 4~6bits intend to enlarge the "max read request size"
                 * (we will do it).  The content of the rest part of this
                 * register is not meaningful to other PCI registers, so
                 * writing the value to 0x54 could be completely wrong.
                 * 0x80 is the lower part of PCI Express device status, non-
                 * reserved bits are RW1C, writing 0 to them will not have
                 * any effect at all.
                 */
#ifdef foo
                uint8_t val;

                val = pci_read_config(dev, 0x79, 1);
                val = (val & ~0x70) | 0x50;
                pci_write_config(dev, 0x54, val, 1);
                pci_write_config(dev, 0x80, 0, 1);
#endif
        }

        /*
         * Apply some PHY fixup from Realtek ...
         */
        if (sc->re_hwrev == RE_HWREV_8110S) {
                CSR_WRITE_1(sc, 0x82, 1);
                re_miibus_writereg(dev, 1, 0xb, 0);
        }
        if (sc->re_caps & RE_C_PHYPMGT) {
                /* Power up PHY */
                re_miibus_writereg(dev, 1, 0x1f, 0);
                re_miibus_writereg(dev, 1, 0xe, 0);
        }

        /* Do MII setup */
        if (mii_phy_probe(dev, &sc->re_miibus,
            re_ifmedia_upd, re_ifmedia_sts)) {
                device_printf(dev, "MII without any phy!\n");
                error = ENXIO;
                goto fail;
        }

        ifp = &sc->arpcom.ac_if;
        ifp->if_softc = sc;
        if_initname(ifp, device_get_name(dev), device_get_unit(dev));
        ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
        ifp->if_ioctl = re_ioctl;
        ifp->if_start = re_start;
#ifdef IFPOLL_ENABLE
        ifp->if_npoll = re_npoll;
#endif
        ifp->if_watchdog = re_watchdog;
        ifp->if_init = re_init;
        if (!RE_IS_8139CP(sc)) /* XXX */
                ifp->if_baudrate = 1000000000;
        else
                ifp->if_baudrate = 100000000;
        ifp->if_nmbclusters = sc->re_rx_desc_cnt;
        ifq_set_maxlen(&ifp->if_snd, qlen);
        ifq_set_ready(&ifp->if_snd);

        ifp->if_capabilities = IFCAP_VLAN_MTU | IFCAP_VLAN_HWTAGGING;
        if (sc->re_caps & RE_C_HWCSUM)
                ifp->if_capabilities |= IFCAP_HWCSUM;

        ifp->if_capenable = ifp->if_capabilities;
        if (ifp->if_capabilities & IFCAP_HWCSUM) {
                /*
                 * RTL8168/8111C generates wrong IP checksummed frame if the
                 * packet has IP options so disable TX IP checksum offloading.
                 */ 
                if (sc->re_hwrev == RE_HWREV_8168CP ||
                    sc->re_hwrev == RE_HWREV_8168C)
                        sc->re_hwassist = CSUM_TCP | CSUM_UDP;
                else
                        sc->re_hwassist = CSUM_IP | CSUM_TCP | CSUM_UDP;
        }
        ifp->if_hwassist = sc->re_hwassist;

        /*
         * Call MI attach routine.
         */
        ether_ifattach(ifp, eaddr, NULL);

        ifq_set_cpuid(&ifp->if_snd, rman_get_cpuid(sc->re_irq));

#ifdef IFPOLL_ENABLE
        ifpoll_compat_setup(&sc->re_npoll, ctx, (struct sysctl_oid *)tree,
            device_get_unit(dev), ifp->if_serializer);
#endif

#ifdef RE_DIAG
        /*
         * Perform hardware diagnostic on the original RTL8169.
         * Some 32-bit cards were incorrectly wired and would
         * malfunction if plugged into a 64-bit slot.
         */
        if (sc->re_hwrev == RE_HWREV_8169) {
                lwkt_serialize_enter(ifp->if_serializer);
                error = re_diag(sc);
                lwkt_serialize_exit(ifp->if_serializer);

                if (error) {
                        device_printf(dev, "hardware diagnostic failure\n");
                        ether_ifdetach(ifp);
                        goto fail;
                }
        }
#endif  /* RE_DIAG */

        /* Hook interrupt last to avoid having to lock softc */
        error = bus_setup_intr(dev, sc->re_irq, INTR_MPSAFE, re_intr, sc,
                               &sc->re_intrhand, ifp->if_serializer);

        if (error) {
                device_printf(dev, "couldn't set up irq\n");
                ether_ifdetach(ifp);
                goto fail;
        }

fail:
        if (error)
                re_detach(dev);

        return (error);
}

/*
 * Shutdown hardware and free up resources. This can be called any
 * time after the mutex has been initialized. It is called in both
 * the error case in attach and the normal detach case so it needs
 * to be careful about only freeing resources that have actually been
 * allocated.
 */
static int
re_detach(device_t dev)
{
        struct re_softc *sc = device_get_softc(dev);
        struct ifnet *ifp = &sc->arpcom.ac_if;

        /* These should only be active if attach succeeded */
        if (device_is_attached(dev)) {
                lwkt_serialize_enter(ifp->if_serializer);
                re_stop(sc);
                bus_teardown_intr(dev, sc->re_irq, sc->re_intrhand);
                lwkt_serialize_exit(ifp->if_serializer);

                ether_ifdetach(ifp);
        }
        if (sc->re_miibus)
                device_delete_child(dev, sc->re_miibus);
        bus_generic_detach(dev);

        if (sc->re_irq)
                bus_release_resource(dev, SYS_RES_IRQ, sc->re_irq_rid,
                                     sc->re_irq);

        if (sc->re_irq_type == PCI_INTR_TYPE_MSI)
                pci_release_msi(dev);

        if (sc->re_res) {
                bus_release_resource(dev, sc->re_res_type, sc->re_res_rid,
                    sc->re_res);
        }

        /* Free DMA stuffs */
        re_freemem(dev);

        return(0);
}

static void
re_setup_rxdesc(struct re_softc *sc, int idx)
{
        bus_addr_t paddr;
        uint32_t cmdstat;
        struct re_desc *d;

        paddr = sc->re_ldata.re_rx_paddr[idx];
        d = &sc->re_ldata.re_rx_list[idx];

        d->re_bufaddr_lo = htole32(RE_ADDR_LO(paddr));
        d->re_bufaddr_hi = htole32(RE_ADDR_HI(paddr));

        cmdstat = sc->re_rxbuf_size | RE_RDESC_CMD_OWN;
        if (idx == (sc->re_rx_desc_cnt - 1))
                cmdstat |= RE_RDESC_CMD_EOR;
        d->re_cmdstat = htole32(cmdstat);
}

static int
re_newbuf_std(struct re_softc *sc, int idx, int init)
{
        bus_dma_segment_t seg;
        bus_dmamap_t map;
        struct mbuf *m;
        int error, nsegs;

        m = m_getcl(init ? M_WAITOK : M_NOWAIT, MT_DATA, M_PKTHDR);
        if (m == NULL) {
                error = ENOBUFS;

                if (init) {
                        if_printf(&sc->arpcom.ac_if, "m_getcl failed\n");
                        return error;
                } else {
                        goto back;
                }
        }
        m->m_len = m->m_pkthdr.len = MCLBYTES;

        /*
         * NOTE:
         * re(4) chips need address of the receive buffer to be 8-byte
         * aligned, so don't call m_adj(m, ETHER_ALIGN) here.
         */

        error = bus_dmamap_load_mbuf_segment(sc->re_ldata.re_rx_mtag,
                        sc->re_ldata.re_rx_spare, m,
                        &seg, 1, &nsegs, BUS_DMA_NOWAIT);
        if (error) {
                m_freem(m);
                if (init) {
                        if_printf(&sc->arpcom.ac_if, "can't load RX mbuf\n");
                        return error;
                } else {
                        goto back;
                }
        }

        if (!init) {
                bus_dmamap_sync(sc->re_ldata.re_rx_mtag,
                                sc->re_ldata.re_rx_dmamap[idx],
                                BUS_DMASYNC_POSTREAD);
                bus_dmamap_unload(sc->re_ldata.re_rx_mtag,
                                  sc->re_ldata.re_rx_dmamap[idx]);
        }
        sc->re_ldata.re_rx_mbuf[idx] = m;
        sc->re_ldata.re_rx_paddr[idx] = seg.ds_addr;

        map = sc->re_ldata.re_rx_dmamap[idx];
        sc->re_ldata.re_rx_dmamap[idx] = sc->re_ldata.re_rx_spare;
        sc->re_ldata.re_rx_spare = map;
back:
        re_setup_rxdesc(sc, idx);
        return error;
}

static int
re_newbuf_jumbo(struct re_softc *sc, int idx, int init)
{
        struct mbuf *m;
        struct re_jbuf *jbuf;
        int error = 0;

        MGETHDR(m, init ? M_WAITOK : M_NOWAIT, MT_DATA);
        if (m == NULL) {
                error = ENOBUFS;
                if (init) {
                        if_printf(&sc->arpcom.ac_if, "MGETHDR failed\n");
                        return error;
                } else {
                        goto back;
                }
        }

        jbuf = re_jbuf_alloc(sc);
        if (jbuf == NULL) {
                m_freem(m);

                error = ENOBUFS;
                if (init) {
                        if_printf(&sc->arpcom.ac_if, "jpool is empty\n");
                        return error;
                } else {
                        goto back;
                }
        }

        m->m_ext.ext_arg = jbuf;
        m->m_ext.ext_buf = jbuf->re_buf;
        m->m_ext.ext_free = re_jbuf_free;
        m->m_ext.ext_ref = re_jbuf_ref;
        m->m_ext.ext_size = sc->re_rxbuf_size;

        m->m_data = m->m_ext.ext_buf;
        m->m_flags |= M_EXT;
        m->m_len = m->m_pkthdr.len = m->m_ext.ext_size;

        /*
         * NOTE:
         * Some re(4) chips(e.g. RTL8101E) need address of the receive buffer
         * to be 8-byte aligned, so don't call m_adj(m, ETHER_ALIGN) here.
         */

        sc->re_ldata.re_rx_mbuf[idx] = m;
        sc->re_ldata.re_rx_paddr[idx] = jbuf->re_paddr;
back:
        re_setup_rxdesc(sc, idx);
        return error;
}

static int
re_tx_list_init(struct re_softc *sc)
{
        bzero(sc->re_ldata.re_tx_list, RE_TX_LIST_SZ(sc));

        sc->re_ldata.re_tx_prodidx = 0;
        sc->re_ldata.re_tx_considx = 0;
        sc->re_ldata.re_tx_free = sc->re_tx_desc_cnt;

        return(0);
}

static int
re_rx_list_init(struct re_softc *sc)
{
        int i, error;

        bzero(sc->re_ldata.re_rx_list, RE_RX_LIST_SZ(sc));

        for (i = 0; i < sc->re_rx_desc_cnt; i++) {
                error = sc->re_newbuf(sc, i, 1);
                if (error)
                        return(error);
        }

        sc->re_ldata.re_rx_prodidx = 0;
        sc->re_head = sc->re_tail = NULL;

        return(0);
}

#define RE_IP4_PACKET   0x1
#define RE_TCP_PACKET   0x2
#define RE_UDP_PACKET   0x4

static __inline uint8_t
re_packet_type(struct re_softc *sc, uint32_t rxstat, uint32_t rxctrl)
{
        uint8_t packet_type = 0;

        if (sc->re_caps & RE_C_MAC2) {
                if (rxctrl & RE_RDESC_CTL_PROTOIP4)
                        packet_type |= RE_IP4_PACKET;
        } else {
                if (rxstat & RE_RDESC_STAT_PROTOID)
                        packet_type |= RE_IP4_PACKET;
        }
        if (RE_TCPPKT(rxstat))
                packet_type |= RE_TCP_PACKET;
        else if (RE_UDPPKT(rxstat))
                packet_type |= RE_UDP_PACKET;
        return packet_type;
}

/*
 * RX handler for C+ and 8169. For the gigE chips, we support
 * the reception of jumbo frames that have been fragmented
 * across multiple 2K mbuf cluster buffers.
 */
static int
re_rxeof(struct re_softc *sc)
{
        struct ifnet *ifp = &sc->arpcom.ac_if;
        struct mbuf *m;
        struct re_desc  *cur_rx;
        uint32_t rxstat, rxctrl;
        int i, total_len, rx = 0;

        for (i = sc->re_ldata.re_rx_prodidx;
             RE_OWN(&sc->re_ldata.re_rx_list[i]) == 0; RE_RXDESC_INC(sc, i)) {
                cur_rx = &sc->re_ldata.re_rx_list[i];
                m = sc->re_ldata.re_rx_mbuf[i];
                total_len = RE_RXBYTES(cur_rx);
                rxstat = le32toh(cur_rx->re_cmdstat);
                rxctrl = le32toh(cur_rx->re_control);

                rx = 1;

#ifdef INVARIANTS
                if (sc->re_flags & RE_F_USE_JPOOL)
                        KKASSERT(rxstat & RE_RDESC_STAT_EOF);
#endif

                if ((rxstat & RE_RDESC_STAT_EOF) == 0) {
                        if (sc->re_flags & RE_F_DROP_RXFRAG) {
                                re_setup_rxdesc(sc, i);
                                continue;
                        }

                        if (sc->re_newbuf(sc, i, 0)) {
                                /* Drop upcoming fragments */
                                sc->re_flags |= RE_F_DROP_RXFRAG;
                                continue;
                        }

                        m->m_len = MCLBYTES;
                        if (sc->re_head == NULL) {
                                sc->re_head = sc->re_tail = m;
                        } else {
                                sc->re_tail->m_next = m;
                                sc->re_tail = m;
                        }
                        continue;
                } else if (sc->re_flags & RE_F_DROP_RXFRAG) {
                        /*
                         * Last fragment of a multi-fragment packet.
                         *
                         * Since error already happened, this fragment
                         * must be dropped as well as the fragment chain.
                         */
                        re_setup_rxdesc(sc, i);
                        re_free_rxchain(sc);
                        sc->re_flags &= ~RE_F_DROP_RXFRAG;
                        continue;
                }

                /*
                 * NOTE: for the 8139C+, the frame length field
                 * is always 12 bits in size, but for the gigE chips,
                 * it is 13 bits (since the max RX frame length is 16K).
                 * Unfortunately, all 32 bits in the status word
                 * were already used, so to make room for the extra
                 * length bit, RealTek took out the 'frame alignment
                 * error' bit and shifted the other status bits
                 * over one slot. The OWN, EOR, FS and LS bits are
                 * still in the same places. We have already extracted
                 * the frame length and checked the OWN bit, so rather
                 * than using an alternate bit mapping, we shift the
                 * status bits one space to the right so we can evaluate
                 * them using the 8169 status as though it was in the
                 * same format as that of the 8139C+.
                 */
                if (!RE_IS_8139CP(sc))
                        rxstat >>= 1;

                if (rxstat & RE_RDESC_STAT_RXERRSUM) {
                        IFNET_STAT_INC(ifp, ierrors, 1);
                        /*
                         * If this is part of a multi-fragment packet,
                         * discard all the pieces.
                         */
                        re_free_rxchain(sc);
                        re_setup_rxdesc(sc, i);
                        continue;
                }

                /*
                 * If allocating a replacement mbuf fails,
                 * reload the current one.
                 */

                if (sc->re_newbuf(sc, i, 0)) {
                        IFNET_STAT_INC(ifp, ierrors, 1);
                        continue;
                }

                if (sc->re_head != NULL) {
                        m->m_len = total_len % MCLBYTES;
                        /* 
                         * Special case: if there's 4 bytes or less
                         * in this buffer, the mbuf can be discarded:
                         * the last 4 bytes is the CRC, which we don't
                         * care about anyway.
                         */
                        if (m->m_len <= ETHER_CRC_LEN) {
                                sc->re_tail->m_len -=
                                    (ETHER_CRC_LEN - m->m_len);
                                m_freem(m);
                        } else {
                                m->m_len -= ETHER_CRC_LEN;
                                sc->re_tail->m_next = m;
                        }
                        m = sc->re_head;
                        sc->re_head = sc->re_tail = NULL;
                        m->m_pkthdr.len = total_len - ETHER_CRC_LEN;
                } else {
                        m->m_pkthdr.len = m->m_len =
                            (total_len - ETHER_CRC_LEN);
                }

                IFNET_STAT_INC(ifp, ipackets, 1);
                m->m_pkthdr.rcvif = ifp;

                /* Do RX checksumming if enabled */

                if (ifp->if_capenable & IFCAP_RXCSUM) {
                        uint8_t packet_type;

                        packet_type = re_packet_type(sc, rxstat, rxctrl);

                        /* Check IP header checksum */
                        if (packet_type & RE_IP4_PACKET) {
                                m->m_pkthdr.csum_flags |= CSUM_IP_CHECKED;
                                if ((rxstat & RE_RDESC_STAT_IPSUMBAD) == 0)
                                        m->m_pkthdr.csum_flags |= CSUM_IP_VALID;
                        }

                        /* Check TCP/UDP checksum */
                        if (((packet_type & RE_TCP_PACKET) &&
                             (rxstat & RE_RDESC_STAT_TCPSUMBAD) == 0) ||
                            ((packet_type & RE_UDP_PACKET) &&
                             (rxstat & RE_RDESC_STAT_UDPSUMBAD) == 0)) {
                                m->m_pkthdr.csum_flags |=
                                    CSUM_DATA_VALID|CSUM_PSEUDO_HDR|
                                    CSUM_FRAG_NOT_CHECKED;
                                m->m_pkthdr.csum_data = 0xffff;
                        }
                }

                if (rxctrl & RE_RDESC_CTL_HASTAG) {
                        m->m_flags |= M_VLANTAG;
                        m->m_pkthdr.ether_vlantag =
                                be16toh((rxctrl & RE_RDESC_CTL_TAGDATA));
                }
                ifp->if_input(ifp, m, NULL, -1);
        }

        sc->re_ldata.re_rx_prodidx = i;

        return rx;
}

#undef RE_IP4_PACKET
#undef RE_TCP_PACKET
#undef RE_UDP_PACKET

static int
re_tx_collect(struct re_softc *sc)
{
        struct ifnet *ifp = &sc->arpcom.ac_if;
        uint32_t txstat;
        int idx, tx = 0;

        for (idx = sc->re_ldata.re_tx_considx;
             sc->re_ldata.re_tx_free < sc->re_tx_desc_cnt;
             RE_TXDESC_INC(sc, idx)) {
                txstat = le32toh(sc->re_ldata.re_tx_list[idx].re_cmdstat);
                if (txstat & RE_TDESC_CMD_OWN)
                        break;

                tx = 1;

                sc->re_ldata.re_tx_list[idx].re_bufaddr_lo = 0;

                /*
                 * We only stash mbufs in the last descriptor
                 * in a fragment chain, which also happens to
                 * be the only place where the TX status bits
                 * are valid.
                 */
                if (txstat & RE_TDESC_CMD_EOF) {
                        bus_dmamap_unload(sc->re_ldata.re_tx_mtag,
                            sc->re_ldata.re_tx_dmamap[idx]);
                        m_freem(sc->re_ldata.re_tx_mbuf[idx]);
                        sc->re_ldata.re_tx_mbuf[idx] = NULL;
                        if (txstat & (RE_TDESC_STAT_EXCESSCOL|
                            RE_TDESC_STAT_COLCNT))
                                IFNET_STAT_INC(ifp, collisions, 1);
                        if (txstat & RE_TDESC_STAT_TXERRSUM)
                                IFNET_STAT_INC(ifp, oerrors, 1);
                        else
                                IFNET_STAT_INC(ifp, opackets, 1);
                }
                sc->re_ldata.re_tx_free++;
        }
        sc->re_ldata.re_tx_considx = idx;

        return tx;
}

static int
re_txeof(struct re_softc *sc)
{
        struct ifnet *ifp = &sc->arpcom.ac_if;
        int tx;

        tx = re_tx_collect(sc);

        /* There is enough free TX descs */
        if (sc->re_ldata.re_tx_free > RE_TXDESC_SPARE)
                ifq_clr_oactive(&ifp->if_snd);

        /*
         * Some chips will ignore a second TX request issued while an
         * existing transmission is in progress. If the transmitter goes
         * idle but there are still packets waiting to be sent, we need
         * to restart the channel here to flush them out. This only seems
         * to be required with the PCIe devices.
         */
        if (sc->re_ldata.re_tx_free < sc->re_tx_desc_cnt)
                CSR_WRITE_1(sc, sc->re_txstart, RE_TXSTART_START);
        else
                ifp->if_timer = 0;

        return tx;
}

static void
re_tick(void *xsc)
{
        struct re_softc *sc = xsc;

        lwkt_serialize_enter(sc->arpcom.ac_if.if_serializer);
        re_tick_serialized(xsc);
        lwkt_serialize_exit(sc->arpcom.ac_if.if_serializer);
}

static void
re_tick_serialized(void *xsc)
{
        struct re_softc *sc = xsc;
        struct ifnet *ifp = &sc->arpcom.ac_if;
        struct mii_data *mii;

        ASSERT_SERIALIZED(ifp->if_serializer);

        mii = device_get_softc(sc->re_miibus);
        mii_tick(mii);
        if (sc->re_flags & RE_F_LINKED) {
                if (!(mii->mii_media_status & IFM_ACTIVE))
                        sc->re_flags &= ~RE_F_LINKED;
        } else {
                if (mii->mii_media_status & IFM_ACTIVE &&
                    IFM_SUBTYPE(mii->mii_media_active) != IFM_NONE) {
                        sc->re_flags |= RE_F_LINKED;
                        if (!ifq_is_empty(&ifp->if_snd))
                                if_devstart(ifp);
                }
        }

        callout_reset(&sc->re_timer, hz, re_tick, sc);
}

#ifdef IFPOLL_ENABLE

static void
re_npoll_compat(struct ifnet *ifp, void *arg __unused, int count)
{
        struct re_softc *sc = ifp->if_softc;

        ASSERT_SERIALIZED(ifp->if_serializer);

        if (sc->re_npoll.ifpc_stcount-- == 0) {
                uint16_t       status;

                sc->re_npoll.ifpc_stcount = sc->re_npoll.ifpc_stfrac;

                status = CSR_READ_2(sc, RE_ISR);
                if (status == 0xffff)
                        return;
                if (status)
                        CSR_WRITE_2(sc, RE_ISR, status);

                /*
                 * XXX check behaviour on receiver stalls.
                 */

                if (status & RE_ISR_SYSTEM_ERR)
                        re_init(sc);
        }

        sc->rxcycles = count;
        re_rxeof(sc);
        re_txeof(sc);

        if (!ifq_is_empty(&ifp->if_snd))
                if_devstart(ifp);
}

static void
re_npoll(struct ifnet *ifp, struct ifpoll_info *info)
{
        struct re_softc *sc = ifp->if_softc;

        ASSERT_SERIALIZED(ifp->if_serializer);

        if (info != NULL) {
                int cpuid = sc->re_npoll.ifpc_cpuid;

                info->ifpi_rx[cpuid].poll_func = re_npoll_compat;
                info->ifpi_rx[cpuid].arg = NULL;
                info->ifpi_rx[cpuid].serializer = ifp->if_serializer;

                if (ifp->if_flags & IFF_RUNNING)
                        re_setup_intr(sc, 0, RE_IMTYPE_NONE);
                ifq_set_cpuid(&ifp->if_snd, cpuid);
        } else {
                if (ifp->if_flags & IFF_RUNNING)
                        re_setup_intr(sc, 1, sc->re_imtype);
                ifq_set_cpuid(&ifp->if_snd, rman_get_cpuid(sc->re_irq));
        }
}
#endif /* IFPOLL_ENABLE */

static void
re_intr(void *arg)
{
        struct re_softc *sc = arg;
        struct ifnet *ifp = &sc->arpcom.ac_if;
        uint16_t status;
        int rx, tx;

        ASSERT_SERIALIZED(ifp->if_serializer);

        if ((sc->re_flags & RE_F_SUSPENDED) ||
            (ifp->if_flags & IFF_RUNNING) == 0)
                return;

        rx = tx = 0;

        status = CSR_READ_2(sc, RE_ISR);
        /* If the card has gone away the read returns 0xffff. */
        if (status == 0xffff)
                goto reload;
        if (status)
                CSR_WRITE_2(sc, RE_ISR, status);

        if ((status & sc->re_intrs) == 0)
                goto reload;

        if (status & (sc->re_rx_ack | RE_ISR_RX_ERR))
                rx |= re_rxeof(sc);

        if (status & (sc->re_tx_ack | RE_ISR_TX_ERR))
                tx |= re_txeof(sc);

        if (status & RE_ISR_SYSTEM_ERR)
                re_init(sc);

        if (status & RE_ISR_LINKCHG) {
                callout_stop(&sc->re_timer);
                re_tick_serialized(sc);
        }

reload:
        if (sc->re_imtype == RE_IMTYPE_SIM) {
                if ((sc->re_flags & RE_F_TIMER_INTR)) {
                        if ((tx | rx) == 0) {
                                /*
                                 * Nothing needs to be processed, fallback
                                 * to use TX/RX interrupts.
                                 */
                                re_setup_intr(sc, 1, RE_IMTYPE_NONE);

                                /*
                                 * Recollect, mainly to avoid the possible
                                 * race introduced by changing interrupt
                                 * masks.
                                 */
                                re_rxeof(sc);
                                tx = re_txeof(sc);
                        } else {
                                CSR_WRITE_4(sc, RE_TIMERCNT, 1); /* reload */
                        }
                } else if (tx | rx) {
                        /*
                         * Assume that using simulated interrupt moderation
                         * (hardware timer based) could reduce the interript
                         * rate.
                         */
                        re_setup_intr(sc, 1, RE_IMTYPE_SIM);
                }
        }

        if (tx && !ifq_is_empty(&ifp->if_snd))
                if_devstart(ifp);
}

static int
re_encap(struct re_softc *sc, struct mbuf **m_head, int *idx0)
{
        struct mbuf *m = *m_head;
        bus_dma_segment_t segs[RE_MAXSEGS];
        bus_dmamap_t map;
        int error, maxsegs, idx, i, nsegs;
        struct re_desc *d, *tx_ring;
        uint32_t cmd_csum, ctl_csum, vlantag;

        KASSERT(sc->re_ldata.re_tx_free > RE_TXDESC_SPARE,
                ("not enough free TX desc"));

        map = sc->re_ldata.re_tx_dmamap[*idx0];

        /*
         * Set up checksum offload. Note: checksum offload bits must
         * appear in all descriptors of a multi-descriptor transmit
         * attempt. (This is according to testing done with an 8169
         * chip. I'm not sure if this is a requirement or a bug.)
         */
        cmd_csum = ctl_csum = 0;
        if (m->m_pkthdr.csum_flags & CSUM_IP) {
                cmd_csum |= RE_TDESC_CMD_IPCSUM;
                ctl_csum |= RE_TDESC_CTL_IPCSUM;
        }
        if (m->m_pkthdr.csum_flags & CSUM_TCP) {
                cmd_csum |= RE_TDESC_CMD_TCPCSUM;
                ctl_csum |= RE_TDESC_CTL_TCPCSUM;
        }
        if (m->m_pkthdr.csum_flags & CSUM_UDP) {
                cmd_csum |= RE_TDESC_CMD_UDPCSUM;
                ctl_csum |= RE_TDESC_CTL_UDPCSUM;
        }

        /* For MAC2 chips, csum flags are set on re_control */
        if (sc->re_caps & RE_C_MAC2)
                cmd_csum = 0;
        else
                ctl_csum = 0;

        if ((sc->re_caps & RE_C_AUTOPAD) == 0) {
                /*
                 * With some of the RealTek chips, using the checksum offload
                 * support in conjunction with the autopadding feature results
                 * in the transmission of corrupt frames. For example, if we
                 * need to send a really small IP fragment that's less than 60
                 * bytes in size, and IP header checksumming is enabled, the
                 * resulting ethernet frame that appears on the wire will
                 * have garbled payload. To work around this, if TX checksum
                 * offload is enabled, we always manually pad short frames out
                 * to the minimum ethernet frame size.
                 *
                 * Note: this appears unnecessary for TCP, and doing it for TCP
                 * with PCIe adapters seems to result in bad checksums.
                 */
                if ((m->m_pkthdr.csum_flags &
                     (CSUM_DELAY_IP | CSUM_DELAY_DATA)) &&
                    (m->m_pkthdr.csum_flags & CSUM_TCP) == 0 &&
                    m->m_pkthdr.len < RE_MIN_FRAMELEN) {
                        error = m_devpad(m, RE_MIN_FRAMELEN);
                        if (error)
                                goto back;
                }
        }

        vlantag = 0;
        if (m->m_flags & M_VLANTAG) {
                vlantag = htobe16(m->m_pkthdr.ether_vlantag) |
                          RE_TDESC_CTL_INSTAG;
        }

        maxsegs = sc->re_ldata.re_tx_free;
        if (maxsegs > RE_MAXSEGS)
                maxsegs = RE_MAXSEGS;

        error = bus_dmamap_load_mbuf_defrag(sc->re_ldata.re_tx_mtag, map,
                        m_head, segs, maxsegs, &nsegs, BUS_DMA_NOWAIT);
        if (error)
                goto back;

        m = *m_head;
        bus_dmamap_sync(sc->re_ldata.re_tx_mtag, map, BUS_DMASYNC_PREWRITE);

        /*
         * Map the segment array into descriptors.  We also keep track
         * of the end of the ring and set the end-of-ring bits as needed,
         * and we set the ownership bits in all except the very first
         * descriptor, whose ownership bits will be turned on later.
         */
        tx_ring = sc->re_ldata.re_tx_list;
        idx = *idx0;
        i = 0;
        for (;;) {
                uint32_t cmdstat;

                d = &tx_ring[idx];

                cmdstat = segs[i].ds_len;
                d->re_bufaddr_lo = htole32(RE_ADDR_LO(segs[i].ds_addr));
                d->re_bufaddr_hi = htole32(RE_ADDR_HI(segs[i].ds_addr));
                if (i == 0)
                        cmdstat |= RE_TDESC_CMD_SOF;
                else
                        cmdstat |= RE_TDESC_CMD_OWN;
                if (idx == (sc->re_tx_desc_cnt - 1))
                        cmdstat |= RE_TDESC_CMD_EOR;
                d->re_cmdstat = htole32(cmdstat | cmd_csum);
                d->re_control = htole32(ctl_csum | vlantag);

                i++;
                if (i == nsegs)
                        break;
                RE_TXDESC_INC(sc, idx);
        }
        d->re_cmdstat |= htole32(RE_TDESC_CMD_EOF);

        /* Transfer ownership of packet to the chip. */
        d->re_cmdstat |= htole32(RE_TDESC_CMD_OWN);
        if (*idx0 != idx)
                tx_ring[*idx0].re_cmdstat |= htole32(RE_TDESC_CMD_OWN);

        /*
         * Insure that the map for this transmission
         * is placed at the array index of the last descriptor
         * in this chain.
         */
        sc->re_ldata.re_tx_dmamap[*idx0] = sc->re_ldata.re_tx_dmamap[idx];
        sc->re_ldata.re_tx_dmamap[idx] = map;

        sc->re_ldata.re_tx_mbuf[idx] = m;
        sc->re_ldata.re_tx_free -= nsegs;

        RE_TXDESC_INC(sc, idx);
        *idx0 = idx;
back:
        if (error) {
                m_freem(*m_head);
                *m_head = NULL;
        }
        return error;
}

/*
 * Main transmit routine for C+ and gigE NICs.
 */

static void
re_start(struct ifnet *ifp, struct ifaltq_subque *ifsq)
{
        struct re_softc *sc = ifp->if_softc;
        struct mbuf *m_head;
        int idx, need_trans, oactive, error;

        ASSERT_ALTQ_SQ_DEFAULT(ifp, ifsq);
        ASSERT_SERIALIZED(ifp->if_serializer);

        if ((sc->re_flags & RE_F_LINKED) == 0) {
                ifq_purge(&ifp->if_snd);
                return;
        }

        if ((ifp->if_flags & IFF_RUNNING) == 0 || ifq_is_oactive(&ifp->if_snd))
                return;

        idx = sc->re_ldata.re_tx_prodidx;

        need_trans = 0;
        oactive = 0;
        while (sc->re_ldata.re_tx_mbuf[idx] == NULL) {
                if (sc->re_ldata.re_tx_free <= RE_TXDESC_SPARE) {
                        if (!oactive) {
                                if (re_tx_collect(sc)) {
                                        oactive = 1;
                                        continue;
                                }
                        }
                        ifq_set_oactive(&ifp->if_snd);
                        break;
                }

                m_head = ifq_dequeue(&ifp->if_snd);
                if (m_head == NULL)
                        break;

                error = re_encap(sc, &m_head, &idx);
                if (error) {
                        /* m_head is freed by re_encap(), if we reach here */
                        IFNET_STAT_INC(ifp, oerrors, 1);

                        if (error == EFBIG && !oactive) {
                                if (re_tx_collect(sc)) {
                                        oactive = 1;
                                        continue;
                                }
                        }
                        ifq_set_oactive(&ifp->if_snd);
                        break;
                }

                oactive = 0;
                need_trans = 1;

                /*
                 * If there's a BPF listener, bounce a copy of this frame
                 * to him.
                 */
                ETHER_BPF_MTAP(ifp, m_head);
        }

        /*
         * If sc->re_ldata.re_tx_mbuf[idx] is not NULL it is possible
         * for OACTIVE to not be properly set when we also do not
         * have sufficient free tx descriptors, leaving packet in
         * ifp->if_snd.  This can cause if_start_dispatch() to loop
         * infinitely so make sure OACTIVE is set properly.
         */
        if (sc->re_ldata.re_tx_free <= RE_TXDESC_SPARE) {
                if (!ifq_is_oactive(&ifp->if_snd)) {
#if 0
                        if_printf(ifp, "Debug: OACTIVE was not set when "
                            "re_tx_free was below minimum!\n");
#endif
                        ifq_set_oactive(&ifp->if_snd);
                }
        }
        if (!need_trans)
                return;

        sc->re_ldata.re_tx_prodidx = idx;

        /*
         * RealTek put the TX poll request register in a different
         * location on the 8169 gigE chip. I don't know why.
         */
        CSR_WRITE_1(sc, sc->re_txstart, RE_TXSTART_START);

        /*
         * Set a timeout in case the chip goes out to lunch.
         */
        ifp->if_timer = 5;
}

static void
re_init(void *xsc)
{
        struct re_softc *sc = xsc;
        struct ifnet *ifp = &sc->arpcom.ac_if;
        struct mii_data *mii;
        int error, framelen;

        ASSERT_SERIALIZED(ifp->if_serializer);

        mii = device_get_softc(sc->re_miibus);

        /*
         * Cancel pending I/O and free all RX/TX buffers.
         */
        re_stop(sc);

        if (sc->re_caps & RE_C_CONTIGRX) {
                if (ifp->if_mtu > ETHERMTU) {
                        KKASSERT(sc->re_ldata.re_jbuf != NULL);
                        sc->re_flags |= RE_F_USE_JPOOL;
                        sc->re_rxbuf_size = RE_FRAMELEN_MAX;
                        sc->re_newbuf = re_newbuf_jumbo;
                } else {
                        sc->re_flags &= ~RE_F_USE_JPOOL;
                        sc->re_rxbuf_size = MCLBYTES;
                        sc->re_newbuf = re_newbuf_std;
                }
        }

        /*
         * Adjust max read request size according to MTU; mainly to
         * improve TX performance for common case (ETHERMTU) on GigE
         * NICs.  However, this could _not_ be done on 10/100 only
         * NICs; their DMA engines will malfunction using non-default
         * max read request size.
         */
        if ((sc->re_caps & (RE_C_PCIE | RE_C_FASTE)) == RE_C_PCIE) {
                if (ifp->if_mtu > ETHERMTU) {
                        /*
                         * 512 seems to be the only value that works
                         * reliably with jumbo frame
                         */
                        pcie_set_max_readrq(sc->re_dev,
                                PCIEM_DEVCTL_MAX_READRQ_512);
                } else {
                        pcie_set_max_readrq(sc->re_dev,
                                PCIEM_DEVCTL_MAX_READRQ_4096);
                }
        }

        /*
         * Enable C+ RX and TX mode, as well as VLAN stripping and
         * RX checksum offload. We must configure the C+ register
         * before all others.
         */
        CSR_WRITE_2(sc, RE_CPLUS_CMD, RE_CPLUSCMD_RXENB | RE_CPLUSCMD_TXENB |
                    RE_CPLUSCMD_PCI_MRW |
                    (ifp->if_capenable & IFCAP_VLAN_HWTAGGING ?
                     RE_CPLUSCMD_VLANSTRIP : 0) |
                    (ifp->if_capenable & IFCAP_RXCSUM ?
                     RE_CPLUSCMD_RXCSUM_ENB : 0));

        /*
         * Init our MAC address.  Even though the chipset
         * documentation doesn't mention it, we need to enter "Config
         * register write enable" mode to modify the ID registers.
         */
        CSR_WRITE_1(sc, RE_EECMD, RE_EEMODE_WRITECFG);
        CSR_WRITE_4(sc, RE_IDR0,
            htole32(*(uint32_t *)(&sc->arpcom.ac_enaddr[0])));
        CSR_WRITE_2(sc, RE_IDR4,
            htole16(*(uint16_t *)(&sc->arpcom.ac_enaddr[4])));
        CSR_WRITE_1(sc, RE_EECMD, RE_EEMODE_OFF);

        /*
         * For C+ mode, initialize the RX descriptors and mbufs.
         */
        error = re_rx_list_init(sc);
        if (error) {
                re_stop(sc);
                return;
        }
        error = re_tx_list_init(sc);
        if (error) {
                re_stop(sc);
                return;
        }

        /*
         * Load the addresses of the RX and TX lists into the chip.
         */
        CSR_WRITE_4(sc, RE_RXLIST_ADDR_HI,
            RE_ADDR_HI(sc->re_ldata.re_rx_list_addr));
        CSR_WRITE_4(sc, RE_RXLIST_ADDR_LO,
            RE_ADDR_LO(sc->re_ldata.re_rx_list_addr));

        CSR_WRITE_4(sc, RE_TXLIST_ADDR_HI,
            RE_ADDR_HI(sc->re_ldata.re_tx_list_addr));
        CSR_WRITE_4(sc, RE_TXLIST_ADDR_LO,
            RE_ADDR_LO(sc->re_ldata.re_tx_list_addr));

        /*
         * Enable transmit and receive.
         */
        CSR_WRITE_1(sc, RE_COMMAND, RE_CMD_TX_ENB|RE_CMD_RX_ENB);

        /*
         * Set the initial TX and RX configuration.
         */
        if (sc->re_flags & RE_F_TESTMODE) {
                if (!RE_IS_8139CP(sc))
                        CSR_WRITE_4(sc, RE_TXCFG,
                                    RE_TXCFG_CONFIG | RE_LOOPTEST_ON);
                else
                        CSR_WRITE_4(sc, RE_TXCFG,
                                    RE_TXCFG_CONFIG | RE_LOOPTEST_ON_CPLUS);
        } else
                CSR_WRITE_4(sc, RE_TXCFG, RE_TXCFG_CONFIG);

        framelen = RE_FRAMELEN(ifp->if_mtu);
        if (framelen < MCLBYTES)
                CSR_WRITE_1(sc, RE_EARLY_TX_THRESH, howmany(MCLBYTES, 128));
        else
                CSR_WRITE_1(sc, RE_EARLY_TX_THRESH, howmany(framelen, 128));

        CSR_WRITE_4(sc, RE_RXCFG, RE_RXCFG_CONFIG);

        /*
         * Program the multicast filter, if necessary.
         */
        re_setmulti(sc);

#ifdef IFPOLL_ENABLE
        /*
         * Disable interrupts if we are polling.
         */
        if (ifp->if_flags & IFF_NPOLLING)
                re_setup_intr(sc, 0, RE_IMTYPE_NONE);
        else    /* otherwise ... */
#endif /* IFPOLL_ENABLE */
        /*
         * Enable interrupts.
         */
        if (sc->re_flags & RE_F_TESTMODE)
                CSR_WRITE_2(sc, RE_IMR, 0);
        else
                re_setup_intr(sc, 1, sc->re_imtype);
        CSR_WRITE_2(sc, RE_ISR, sc->re_intrs);

        /* Start RX/TX process. */
        CSR_WRITE_4(sc, RE_MISSEDPKT, 0);

#ifdef notdef
        /* Enable receiver and transmitter. */
        CSR_WRITE_1(sc, RE_COMMAND, RE_CMD_TX_ENB|RE_CMD_RX_ENB);
#endif

        /*
         * For 8169 gigE NICs, set the max allowed RX packet
         * size so we can receive jumbo frames.
         */
        if (!RE_IS_8139CP(sc)) {
                if (sc->re_caps & RE_C_CONTIGRX)
                        CSR_WRITE_2(sc, RE_MAXRXPKTLEN, sc->re_rxbuf_size);
                else
                        CSR_WRITE_2(sc, RE_MAXRXPKTLEN, 16383);
        }

        if (sc->re_flags & RE_F_TESTMODE)
                return;

        mii_mediachg(mii);

        CSR_WRITE_1(sc, RE_CFG1, RE_CFG1_DRVLOAD|RE_CFG1_FULLDUPLEX);

        ifp->if_flags |= IFF_RUNNING;
        ifq_clr_oactive(&ifp->if_snd);

        callout_reset(&sc->re_timer, hz, re_tick, sc);
}

/*
 * Set media options.
 */
static int
re_ifmedia_upd(struct ifnet *ifp)
{
        struct re_softc *sc = ifp->if_softc;
        struct mii_data *mii;

        ASSERT_SERIALIZED(ifp->if_serializer);

        mii = device_get_softc(sc->re_miibus);
        mii_mediachg(mii);

        return(0);
}

/*
 * Report current media status.
 */
static void
re_ifmedia_sts(struct ifnet *ifp, struct ifmediareq *ifmr)
{
        struct re_softc *sc = ifp->if_softc;
        struct mii_data *mii;

        ASSERT_SERIALIZED(ifp->if_serializer);

        mii = device_get_softc(sc->re_miibus);

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

static int
re_ioctl(struct ifnet *ifp, u_long command, caddr_t data, struct ucred *cr)
{
        struct re_softc *sc = ifp->if_softc;
        struct ifreq *ifr = (struct ifreq *) data;
        struct mii_data *mii;
        int error = 0, mask;

        ASSERT_SERIALIZED(ifp->if_serializer);

        switch(command) {
        case SIOCSIFMTU:
                if (ifr->ifr_mtu > sc->re_maxmtu) {
                        error = EINVAL;
                } else if (ifp->if_mtu != ifr->ifr_mtu) {
                        ifp->if_mtu = ifr->ifr_mtu;
                        if (ifp->if_flags & IFF_RUNNING)
                                ifp->if_init(sc);
                }
                break;

        case SIOCSIFFLAGS:
                if (ifp->if_flags & IFF_UP) {
                        if (ifp->if_flags & IFF_RUNNING) {
                                if ((ifp->if_flags ^ sc->re_if_flags) &
                                    (IFF_PROMISC | IFF_ALLMULTI))
                                        re_setmulti(sc);
                        } else {
                                re_init(sc);
                        }
                } else if (ifp->if_flags & IFF_RUNNING) {
                        re_stop(sc);
                }
                sc->re_if_flags = ifp->if_flags;
                break;

        case SIOCADDMULTI:
        case SIOCDELMULTI:
                re_setmulti(sc);
                break;

        case SIOCGIFMEDIA:
        case SIOCSIFMEDIA:
                mii = device_get_softc(sc->re_miibus);
                error = ifmedia_ioctl(ifp, ifr, &mii->mii_media, command);
                break;

        case SIOCSIFCAP:
                mask = (ifr->ifr_reqcap ^ ifp->if_capenable) &
                       ifp->if_capabilities;
                ifp->if_capenable ^= mask;

                if (mask & IFCAP_HWCSUM) {
                        if (ifp->if_capenable & IFCAP_TXCSUM)
                                ifp->if_hwassist = sc->re_hwassist;
                        else
                                ifp->if_hwassist = 0;
                }
                if (mask && (ifp->if_flags & IFF_RUNNING))
                        re_init(sc);
                break;

        default:
                error = ether_ioctl(ifp, command, data);
                break;
        }
        return(error);
}

static void
re_watchdog(struct ifnet *ifp)
{
        struct re_softc *sc = ifp->if_softc;

        ASSERT_SERIALIZED(ifp->if_serializer);

        if_printf(ifp, "watchdog timeout\n");

        IFNET_STAT_INC(ifp, oerrors, 1);

        re_txeof(sc);
        re_rxeof(sc);

        re_init(sc);

        if (!ifq_is_empty(&ifp->if_snd))
                if_devstart(ifp);
}

/*
 * Stop the adapter and free any mbufs allocated to the
 * RX and TX lists.
 */
static void
re_stop(struct re_softc *sc)
{
        struct ifnet *ifp = &sc->arpcom.ac_if;
        int i;

        ASSERT_SERIALIZED(ifp->if_serializer);

        /* Reset the adapter. */
        re_reset(sc, ifp->if_flags & IFF_RUNNING);

        ifp->if_timer = 0;
        callout_stop(&sc->re_timer);

        ifp->if_flags &= ~IFF_RUNNING;
        ifq_clr_oactive(&ifp->if_snd);
        sc->re_flags &= ~(RE_F_TIMER_INTR | RE_F_DROP_RXFRAG | RE_F_LINKED);

        CSR_WRITE_1(sc, RE_COMMAND, 0x00);
        CSR_WRITE_2(sc, RE_IMR, 0x0000);
        CSR_WRITE_2(sc, RE_ISR, 0xFFFF);

        re_free_rxchain(sc);

        /* Free the TX list buffers. */
        for (i = 0; i < sc->re_tx_desc_cnt; i++) {
                if (sc->re_ldata.re_tx_mbuf[i] != NULL) {
                        bus_dmamap_unload(sc->re_ldata.re_tx_mtag,
                                          sc->re_ldata.re_tx_dmamap[i]);
                        m_freem(sc->re_ldata.re_tx_mbuf[i]);
                        sc->re_ldata.re_tx_mbuf[i] = NULL;
                }
        }

        /* Free the RX list buffers. */
        for (i = 0; i < sc->re_rx_desc_cnt; i++) {
                if (sc->re_ldata.re_rx_mbuf[i] != NULL) {
                        if ((sc->re_flags & RE_F_USE_JPOOL) == 0) {
                                bus_dmamap_unload(sc->re_ldata.re_rx_mtag,
                                                  sc->re_ldata.re_rx_dmamap[i]);
                        }
                        m_freem(sc->re_ldata.re_rx_mbuf[i]);
                        sc->re_ldata.re_rx_mbuf[i] = NULL;
                }
        }
}

/*
 * Device suspend routine.  Stop the interface and save some PCI
 * settings in case the BIOS doesn't restore them properly on
 * resume.
 */
static int
re_suspend(device_t dev)
{
#ifndef BURN_BRIDGES
        int i;
#endif
        struct re_softc *sc = device_get_softc(dev);
        struct ifnet *ifp = &sc->arpcom.ac_if;

        lwkt_serialize_enter(ifp->if_serializer);

        re_stop(sc);

#ifndef BURN_BRIDGES
        for (i = 0; i < 5; i++)
                sc->saved_maps[i] = pci_read_config(dev, PCIR_MAPS + i * 4, 4);
        sc->saved_biosaddr = pci_read_config(dev, PCIR_BIOS, 4);
        sc->saved_intline = pci_read_config(dev, PCIR_INTLINE, 1);
        sc->saved_cachelnsz = pci_read_config(dev, PCIR_CACHELNSZ, 1);
        sc->saved_lattimer = pci_read_config(dev, PCIR_LATTIMER, 1);
#endif

        sc->re_flags |= RE_F_SUSPENDED;

        lwkt_serialize_exit(ifp->if_serializer);

        return (0);
}

/*
 * Device resume routine.  Restore some PCI settings in case the BIOS
 * doesn't, re-enable busmastering, and restart the interface if
 * appropriate.
 */
static int
re_resume(device_t dev)
{
        struct re_softc *sc = device_get_softc(dev);
        struct ifnet *ifp = &sc->arpcom.ac_if;
#ifndef BURN_BRIDGES
        int i;
#endif

        lwkt_serialize_enter(ifp->if_serializer);

#ifndef BURN_BRIDGES
        /* better way to do this? */
        for (i = 0; i < 5; i++)
                pci_write_config(dev, PCIR_MAPS + i * 4, sc->saved_maps[i], 4);
        pci_write_config(dev, PCIR_BIOS, sc->saved_biosaddr, 4);
        pci_write_config(dev, PCIR_INTLINE, sc->saved_intline, 1);
        pci_write_config(dev, PCIR_CACHELNSZ, sc->saved_cachelnsz, 1);
        pci_write_config(dev, PCIR_LATTIMER, sc->saved_lattimer, 1);

        /* reenable busmastering */
        pci_enable_busmaster(dev);
        pci_enable_io(dev, SYS_RES_IOPORT);
#endif

        /* reinitialize interface if necessary */
        if (ifp->if_flags & IFF_UP)
                re_init(sc);

        sc->re_flags &= ~RE_F_SUSPENDED;

        lwkt_serialize_exit(ifp->if_serializer);

        return (0);
}

/*
 * Stop all chip I/O so that the kernel's probe routines don't
 * get confused by errant DMAs when rebooting.
 */
static void
re_shutdown(device_t dev)
{
        struct re_softc *sc = device_get_softc(dev);
        struct ifnet *ifp = &sc->arpcom.ac_if;

        lwkt_serialize_enter(ifp->if_serializer);
        re_stop(sc);
        lwkt_serialize_exit(ifp->if_serializer);
}

static int
re_sysctl_rxtime(SYSCTL_HANDLER_ARGS)
{
        struct re_softc *sc = arg1;

        return re_sysctl_hwtime(oidp, arg1, arg2, req, &sc->re_rx_time);
}

static int
re_sysctl_txtime(SYSCTL_HANDLER_ARGS)
{
        struct re_softc *sc = arg1;

        return re_sysctl_hwtime(oidp, arg1, arg2, req, &sc->re_tx_time);
}

static int
re_sysctl_hwtime(SYSCTL_HANDLER_ARGS, int *hwtime)
{
        struct re_softc *sc = arg1;
        struct ifnet *ifp = &sc->arpcom.ac_if;
        int error, v;

        lwkt_serialize_enter(ifp->if_serializer);

        v = *hwtime;
        error = sysctl_handle_int(oidp, &v, 0, req);
        if (error || req->newptr == NULL)
                goto back;

        if (v <= 0) {
                error = EINVAL;
                goto back;
        }

        if (v != *hwtime) {
                *hwtime = v;

                if ((ifp->if_flags & (IFF_RUNNING | IFF_NPOLLING)) ==
                    IFF_RUNNING && sc->re_imtype == RE_IMTYPE_HW)
                        re_setup_hw_im(sc);
        }
back:
        lwkt_serialize_exit(ifp->if_serializer);
        return error;
}

static int
re_sysctl_simtime(SYSCTL_HANDLER_ARGS)
{
        struct re_softc *sc = arg1;
        struct ifnet *ifp = &sc->arpcom.ac_if;
        int error, v;

        lwkt_serialize_enter(ifp->if_serializer);

        v = sc->re_sim_time;
        error = sysctl_handle_int(oidp, &v, 0, req);
        if (error || req->newptr == NULL)
                goto back;

        if (v <= 0) {
                error = EINVAL;
                goto back;
        }

        if (v != sc->re_sim_time) {
                sc->re_sim_time = v;

                if ((ifp->if_flags & (IFF_RUNNING | IFF_NPOLLING)) ==
                    IFF_RUNNING && sc->re_imtype == RE_IMTYPE_SIM) {
#ifdef foo
                        int reg;

                        /*
                         * Following code causes various strange
                         * performance problems.  Hmm ...
                         */
                        CSR_WRITE_2(sc, RE_IMR, 0);
                        if (!RE_IS_8139CP(sc))
                                reg = RE_TIMERINT_8169;
                        else
                                reg = RE_TIMERINT;
                        CSR_WRITE_4(sc, reg, 0);
                        CSR_READ_4(sc, reg); /* flush */

                        CSR_WRITE_2(sc, RE_IMR, sc->re_intrs);
                        re_setup_sim_im(sc);
#else
                        re_setup_intr(sc, 0, RE_IMTYPE_NONE);
                        DELAY(10);
                        re_setup_intr(sc, 1, RE_IMTYPE_SIM);
#endif
                }
        }
back:
        lwkt_serialize_exit(ifp->if_serializer);
        return error;
}

static int
re_sysctl_imtype(SYSCTL_HANDLER_ARGS)
{
        struct re_softc *sc = arg1;
        struct ifnet *ifp = &sc->arpcom.ac_if;
        int error, v;

        lwkt_serialize_enter(ifp->if_serializer);

        v = sc->re_imtype;
        error = sysctl_handle_int(oidp, &v, 0, req);
        if (error || req->newptr == NULL)
                goto back;

        if (v != RE_IMTYPE_HW && v != RE_IMTYPE_SIM && v != RE_IMTYPE_NONE) {
                error = EINVAL;
                goto back;
        }
        if (v == RE_IMTYPE_HW && (sc->re_caps & RE_C_HWIM) == 0) {
                /* Can't do hardware interrupt moderation */
                error = EOPNOTSUPP;
                goto back;
        }

        if (v != sc->re_imtype) {
                sc->re_imtype = v;
                if ((ifp->if_flags & (IFF_RUNNING | IFF_NPOLLING)) ==
                    IFF_RUNNING)
                        re_setup_intr(sc, 1, sc->re_imtype);
        }
back:
        lwkt_serialize_exit(ifp->if_serializer);
        return error;
}

static void
re_setup_hw_im(struct re_softc *sc)
{
        KKASSERT(sc->re_caps & RE_C_HWIM);

        /*
         * Interrupt moderation
         *
         * 0xABCD
         * A - unknown (maybe TX related)
         * B - TX timer (unit: 25us)
         * C - unknown (maybe RX related)
         * D - RX timer (unit: 25us)
         *
         *
         * re(4)'s interrupt moderation is actually controlled by
         * two variables, like most other NICs (bge, bce etc.)
         * o  timer
         * o  number of packets [P]
         *
         * The logic relationship between these two variables is
         * similar to other NICs too:
         * if (timer expire || packets > [P])
         *     Interrupt is delivered
         *
         * Currently we only know how to set 'timer', but not
         * 'number of packets', which should be ~30, as far as I
         * tested (sink ~900Kpps, interrupt rate is 30KHz)
         */
        CSR_WRITE_2(sc, RE_IM,
                    RE_IM_RXTIME(sc->re_rx_time) |
                    RE_IM_TXTIME(sc->re_tx_time) |
                    RE_IM_MAGIC);
}

static void
re_disable_hw_im(struct re_softc *sc)
{
        if (sc->re_caps & RE_C_HWIM)
                CSR_WRITE_2(sc, RE_IM, 0);
}

static void
re_setup_sim_im(struct re_softc *sc)
{
        if (!RE_IS_8139CP(sc)) {
                uint32_t ticks;

                /*
                 * Datasheet says tick decreases at bus speed,
                 * but it seems the clock runs a little bit
                 * faster, so we do some compensation here.
                 */
                ticks = (sc->re_sim_time * sc->re_bus_speed * 8) / 5;
                CSR_WRITE_4(sc, RE_TIMERINT_8169, ticks);
        } else {
                CSR_WRITE_4(sc, RE_TIMERINT, 0x400); /* XXX */
        }
        CSR_WRITE_4(sc, RE_TIMERCNT, 1); /* reload */
        sc->re_flags |= RE_F_TIMER_INTR;
}

static void
re_disable_sim_im(struct re_softc *sc)
{
        if (!RE_IS_8139CP(sc))
                CSR_WRITE_4(sc, RE_TIMERINT_8169, 0);
        else
                CSR_WRITE_4(sc, RE_TIMERINT, 0);
        sc->re_flags &= ~RE_F_TIMER_INTR;
}

static void
re_config_imtype(struct re_softc *sc, int imtype)
{
        switch (imtype) {
        case RE_IMTYPE_HW:
                KKASSERT(sc->re_caps & RE_C_HWIM);
                /* FALL THROUGH */
        case RE_IMTYPE_NONE:
                sc->re_intrs = RE_INTRS;
                sc->re_rx_ack = RE_ISR_RX_OK | RE_ISR_FIFO_OFLOW |
                                RE_ISR_RX_OVERRUN;
                sc->re_tx_ack = RE_ISR_TX_OK;
                break;

        case RE_IMTYPE_SIM:
                sc->re_intrs = RE_INTRS_TIMER;
                sc->re_rx_ack = RE_ISR_TIMEOUT_EXPIRED;
                sc->re_tx_ack = RE_ISR_TIMEOUT_EXPIRED;
                break;

        default:
                panic("%s: unknown imtype %d",
                      sc->arpcom.ac_if.if_xname, imtype);
        }
}

static void
re_setup_intr(struct re_softc *sc, int enable_intrs, int imtype)
{
        re_config_imtype(sc, imtype);

        if (enable_intrs)
                CSR_WRITE_2(sc, RE_IMR, sc->re_intrs);
        else
                CSR_WRITE_2(sc, RE_IMR, 0); 

        sc->re_npoll.ifpc_stcount = 0;

        switch (imtype) {
        case RE_IMTYPE_NONE:
                re_disable_sim_im(sc);
                re_disable_hw_im(sc);
                break;

        case RE_IMTYPE_HW:
                KKASSERT(sc->re_caps & RE_C_HWIM);
                re_disable_sim_im(sc);
                re_setup_hw_im(sc);
                break;

        case RE_IMTYPE_SIM:
                re_disable_hw_im(sc);
                re_setup_sim_im(sc);
                break;

        default:
                panic("%s: unknown imtype %d",
                      sc->arpcom.ac_if.if_xname, imtype);
        }
}

static void
re_get_eaddr(struct re_softc *sc, uint8_t *eaddr)
{
        int i;

        if (sc->re_caps & RE_C_EE_EADDR) {
                uint16_t re_did;

                re_get_eewidth(sc);
                re_read_eeprom(sc, (caddr_t)&re_did, 0, 1);
                if (re_did == 0x8128) {
                        uint16_t as[ETHER_ADDR_LEN / 2];

                        /*
                         * Get station address from the EEPROM.
                         */
                        re_read_eeprom(sc, (caddr_t)as, sc->re_ee_eaddr, 3);
                        for (i = 0; i < ETHER_ADDR_LEN / 2; i++)
                                as[i] = le16toh(as[i]);
                        bcopy(as, eaddr, ETHER_ADDR_LEN);
                        return;
                }
        }

        /*
         * Get station address from IDRx.
         */
        for (i = 0; i < ETHER_ADDR_LEN; ++i)
                eaddr[i] = CSR_READ_1(sc, RE_IDR0 + i);
}

static int
re_jpool_alloc(struct re_softc *sc)
{
        struct re_list_data *ldata = &sc->re_ldata;
        struct re_jbuf *jbuf;
        bus_addr_t paddr;
        bus_size_t jpool_size;
        bus_dmamem_t dmem;
        caddr_t buf;
        int i, error;

        lwkt_serialize_init(&ldata->re_jbuf_serializer);

        ldata->re_jbuf = kmalloc(sizeof(struct re_jbuf) * RE_JBUF_COUNT(sc),
                                 M_DEVBUF, M_WAITOK | M_ZERO);

        jpool_size = RE_JBUF_COUNT(sc) * RE_JBUF_SIZE;

        error = bus_dmamem_coherent(sc->re_parent_tag,
                        RE_RXBUF_ALIGN, 0,
                        BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR,
                        jpool_size, BUS_DMA_WAITOK, &dmem);
        if (error) {
                device_printf(sc->re_dev, "could not allocate jumbo memory\n");
                return error;
        }
        ldata->re_jpool_tag = dmem.dmem_tag;
        ldata->re_jpool_map = dmem.dmem_map;
        ldata->re_jpool = dmem.dmem_addr;
        paddr = dmem.dmem_busaddr;

        /* ..and split it into 9KB chunks */
        SLIST_INIT(&ldata->re_jbuf_free);

        buf = ldata->re_jpool;
        for (i = 0; i < RE_JBUF_COUNT(sc); i++) {
                jbuf = &ldata->re_jbuf[i];

                jbuf->re_sc = sc;
                jbuf->re_inuse = 0;
                jbuf->re_slot = i;
                jbuf->re_buf = buf;
                jbuf->re_paddr = paddr;

                SLIST_INSERT_HEAD(&ldata->re_jbuf_free, jbuf, re_link);

                buf += RE_JBUF_SIZE;
                paddr += RE_JBUF_SIZE;
        }
        return 0;
}

static void
re_jpool_free(struct re_softc *sc)
{
        struct re_list_data *ldata = &sc->re_ldata;

        if (ldata->re_jpool_tag != NULL) {
                bus_dmamap_unload(ldata->re_jpool_tag, ldata->re_jpool_map);
                bus_dmamem_free(ldata->re_jpool_tag, ldata->re_jpool,
                                ldata->re_jpool_map);
                bus_dma_tag_destroy(ldata->re_jpool_tag);
                ldata->re_jpool_tag = NULL;
        }

        if (ldata->re_jbuf != NULL) {
                kfree(ldata->re_jbuf, M_DEVBUF);
                ldata->re_jbuf = NULL;
        }
}

static struct re_jbuf *
re_jbuf_alloc(struct re_softc *sc)
{
        struct re_list_data *ldata = &sc->re_ldata;
        struct re_jbuf *jbuf;

        lwkt_serialize_enter(&ldata->re_jbuf_serializer);

        jbuf = SLIST_FIRST(&ldata->re_jbuf_free);
        if (jbuf != NULL) {
                SLIST_REMOVE_HEAD(&ldata->re_jbuf_free, re_link);
                jbuf->re_inuse = 1;
        }

        lwkt_serialize_exit(&ldata->re_jbuf_serializer);

        return jbuf;
}

static void
re_jbuf_free(void *arg)
{
        struct re_jbuf *jbuf = arg;
        struct re_softc *sc = jbuf->re_sc;
        struct re_list_data *ldata = &sc->re_ldata;

        if (&ldata->re_jbuf[jbuf->re_slot] != jbuf) {
                panic("%s: free wrong jumbo buffer",
                      sc->arpcom.ac_if.if_xname);
        } else if (jbuf->re_inuse == 0) {
                panic("%s: jumbo buffer already freed",
                      sc->arpcom.ac_if.if_xname);
        }

        lwkt_serialize_enter(&ldata->re_jbuf_serializer);
        atomic_subtract_int(&jbuf->re_inuse, 1);
        if (jbuf->re_inuse == 0)
                SLIST_INSERT_HEAD(&ldata->re_jbuf_free, jbuf, re_link);
        lwkt_serialize_exit(&ldata->re_jbuf_serializer);
}

static void
re_jbuf_ref(void *arg)
{
        struct re_jbuf *jbuf = arg;
        struct re_softc *sc = jbuf->re_sc;
        struct re_list_data *ldata = &sc->re_ldata;

        if (&ldata->re_jbuf[jbuf->re_slot] != jbuf) {
                panic("%s: ref wrong jumbo buffer",
                      sc->arpcom.ac_if.if_xname);
        } else if (jbuf->re_inuse == 0) {
                panic("%s: jumbo buffer already freed",
                      sc->arpcom.ac_if.if_xname);
        }
        atomic_add_int(&jbuf->re_inuse, 1);
}