Add a new csum flag to tell IP defragmenter that csum_data does _not_

[dragonfly/port-amd64.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 $
 * $DragonFly: src/sys/dev/netif/re/if_re.c,v 1.36 2007/08/14 13:30:35 sephe 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.
 */

#include "opt_polling.h"

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/endian.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
/* #include <sys/module.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_types.h>
#include <net/vlan/if_vlan_var.h>

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

#include <bus/pci/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>

#define RE_CSUM_FEATURES    (CSUM_IP | CSUM_TCP | CSUM_UDP)
#if 0
#define RE_DISABLE_HWCSUM
#endif

/*
 * Various supported device vendors/types and their names.
 */
static const struct re_type re_devs[] = {
        { PCI_VENDOR_DLINK, PCI_PRODUCT_DLINK_DGE528T, RE_HWREV_8169S,
                "D-Link DGE-528(T) Gigabit Ethernet Adapter" },
        { PCI_VENDOR_REALTEK, PCI_PRODUCT_REALTEK_RT8139, RE_HWREV_8139CPLUS,
                "RealTek 8139C+ 10/100BaseTX" },
        { PCI_VENDOR_REALTEK, PCI_PRODUCT_REALTEK_RT8101E, RE_HWREV_8101E,
                "RealTek 8101E PCIe 10/100baseTX" },
        { PCI_VENDOR_REALTEK, PCI_PRODUCT_REALTEK_RT8168, RE_HWREV_8168_SPIN1,
                "RealTek 8168/8111B PCIe Gigabit Ethernet" },
        { PCI_VENDOR_REALTEK, PCI_PRODUCT_REALTEK_RT8168, RE_HWREV_8168_SPIN2,
                "RealTek 8168/8111B PCIe Gigabit Ethernet" },
        { PCI_VENDOR_REALTEK, PCI_PRODUCT_REALTEK_RT8168, RE_HWREV_8168_SPIN3,
                "RealTek 8168B/8111B PCIe Gigabit Ethernet" },
        { PCI_VENDOR_REALTEK, PCI_PRODUCT_REALTEK_RT8169, RE_HWREV_8169,
                "RealTek 8169 Gigabit Ethernet" },
        { PCI_VENDOR_REALTEK, PCI_PRODUCT_REALTEK_RT8169, RE_HWREV_8169S,
                "RealTek 8169S Single-chip Gigabit Ethernet" },
        { PCI_VENDOR_REALTEK, PCI_PRODUCT_REALTEK_RT8169, RE_HWREV_8169_8110SB,
                "RealTek 8169SB/8110SB Single-chip Gigabit Ethernet" },
        { PCI_VENDOR_REALTEK, PCI_PRODUCT_REALTEK_RT8169, RE_HWREV_8169_8110SC,
                "RealTek 8169SC/8110SC Single-chip Gigabit Ethernet" },
        { PCI_VENDOR_REALTEK, PCI_PRODUCT_REALTEK_RT8169SC, RE_HWREV_8169_8110SC,
                "RealTek 8169SC/8110SC Single-chip Gigabit Ethernet" },
        { PCI_VENDOR_REALTEK, PCI_PRODUCT_REALTEK_RT8169, RE_HWREV_8110S,
                "RealTek 8110S Single-chip Gigabit Ethernet" },
        { PCI_VENDOR_COREGA, PCI_PRODUCT_COREGA_CG_LAPCIGT, RE_HWREV_8169S,
                "Corega CG-LAPCIGT Gigabit Ethernet" },
        { PCI_VENDOR_LINKSYS, PCI_PRODUCT_LINKSYS_EG1032, RE_HWREV_8169S,
                "Linksys EG1032 Gigabit Ethernet" },
        { PCI_VENDOR_USR2, PCI_PRODUCT_USR2_997902, RE_HWREV_8169S,
                "US Robotics 997902 Gigabit Ethernet" },
        { 0, 0, 0, NULL }
};

static const struct re_hwrev re_hwrevs[] = {
        { RE_HWREV_8139CPLUS,   RE_8139CPLUS,   RE_F_HASMPC,    "C+" },
        { RE_HWREV_8168_SPIN1,  RE_8169,        RE_F_PCIE,      "8168" },
        { RE_HWREV_8168_SPIN2,  RE_8169,        RE_F_PCIE,      "8168" },
        { RE_HWREV_8168_SPIN3,  RE_8169,        RE_F_PCIE,      "8168" },
        { RE_HWREV_8169,        RE_8169,        RE_F_HASMPC,    "8169" },
        { RE_HWREV_8169S,       RE_8169,        RE_F_HASMPC,    "8169S" },
        { RE_HWREV_8110S,       RE_8169,        RE_F_HASMPC,    "8110S" },
        { RE_HWREV_8169_8110SB, RE_8169,        RE_F_HASMPC,    "8169SB" },
        { RE_HWREV_8169_8110SC, RE_8169,        0,              "8169SC" },
        { RE_HWREV_8100E,       RE_8169,        RE_F_HASMPC,    "8100E" },
        { RE_HWREV_8101E,       RE_8169,        RE_F_PCIE,      "8101E" },
        { 0, 0, 0, NULL }
};

static int      re_probe(device_t);
static int      re_attach(device_t);
static int      re_detach(device_t);

static int      re_encap(struct re_softc *, struct mbuf **, int *, int *);

static void     re_dma_map_addr(void *, bus_dma_segment_t *, int, int);
static void     re_dma_map_desc(void *, bus_dma_segment_t *, int,
                                bus_size_t, int);
static int      re_allocmem(device_t, struct re_softc *);
static int      re_newbuf(struct re_softc *, int, struct mbuf *);
static int      re_rx_list_init(struct re_softc *);
static int      re_tx_list_init(struct re_softc *);
static void     re_rxeof(struct re_softc *);
static void     re_txeof(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 *);
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_suspend(device_t);
static int      re_resume(device_t);
static void     re_shutdown(device_t);
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 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 *);

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

#ifdef DEVICE_POLLING
static void     re_poll(struct ifnet *ifp, enum poll_cmd cmd, int count);
#endif

static int      re_sysctl_tx_moderation(SYSCTL_HANDLER_ARGS);

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),

        { 0, 0 }
};

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

static devclass_t re_devclass;

DECLARE_DUMMY_MODULE(if_re);
DRIVER_MODULE(if_re, pci, re_driver, re_devclass, 0, 0);
DRIVER_MODULE(if_re, cardbus, re_driver, re_devclass, 0, 0);
DRIVER_MODULE(miibus, re, miibus_driver, miibus_devclass, 0, 0);

#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))

/*
 * 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 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 (sc->re_type == RE_8169) {
                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 (sc->re_type == RE_8139CPLUS && 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 (sc->re_type == RE_8169)
                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;
                if (sc->re_type == RE_8139CPLUS) {
                        /* 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);

        if (ifp->if_flags & IFF_ALLMULTI || ifp->if_flags & IFF_PROMISC) {
                rxfilt |= RE_RXCFG_RX_MULTI;
                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 */
        LIST_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_flags & RE_F_PCIE) {
                CSR_WRITE_4(sc, RE_MAR0, bswap32(hashes[0]));
                CSR_WRITE_4(sc, RE_MAR4, bswap32(hashes[1]));
        } 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 i;

        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");

        CSR_WRITE_1(sc, 0x82, 1);
}

#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;
        uint32_t rxstat;
        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' };

        /* Allocate a single mbuf */

        MGETHDR(m0, MB_DONTWAIT, 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_testmode = 1;
        re_reset(sc);
        re_init(sc);
        sc->re_link = 1;
        if (sc->re_type == RE_8169)
                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_list_tag,
                        sc->re_ldata.re_rx_list_map, BUS_DMASYNC_POSTREAD);
        bus_dmamap_sync(sc->re_ldata.re_mtag, sc->re_ldata.re_rx_dmamap[0],
                        BUS_DMASYNC_POSTWRITE);
        bus_dmamap_unload(sc->re_ldata.re_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);
        rxstat = le32toh(cur_rx->re_cmdstat);

        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: %6D/%6D/0x%x\n",
                    dst, ":", src, ":", ETHERTYPE_IP);
                if_printf(ifp, "received RX data: %6D/%6D/0x%x\n",
                    eh->ether_dhost, ":",  eh->ether_shost, ":",
                    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_testmode = 0;
        sc->re_link = 0;
        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;
        struct re_softc *sc;
        int rid;
        uint32_t hwrev;
        uint16_t vendor, product;

        t = re_devs;

        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;

        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);

        hwrev = CSR_READ_4(sc, RE_TXCFG) & RE_TXCFG_HWREV;
        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 (; t->re_name != NULL; t++) {
                if (product == t->re_did && vendor == t->re_vid &&
                    t->re_basetype == hwrev) {
                        device_set_desc(dev, t->re_name);
                        return(0);
                }
        }
        return(ENXIO);
}

/*
 * This routine takes the segment list provided as the result of
 * a bus_dma_map_load() operation and assigns the addresses/lengths
 * to RealTek DMA descriptors. This can be called either by the RX
 * code or the TX code. In the RX case, we'll probably wind up mapping
 * at most one segment. For the TX case, there could be any number of
 * segments since TX packets may span multiple mbufs. In either case,
 * if the number of segments is larger than the re_maxsegs limit
 * specified by the caller, we abort the mapping operation. Sadly,
 * whoever designed the buffer mapping API did not provide a way to
 * return an error from here, so we have to fake it a bit.
 */

static void
re_dma_map_desc(void *arg, bus_dma_segment_t *segs, int nseg,
                bus_size_t mapsize, int error)
{
        struct re_dmaload_arg *ctx;
        struct re_desc *d = NULL;
        int i = 0, idx;
        uint32_t cmdstat;

        if (error)
                return;

        ctx = arg;

        /* Signal error to caller if there's too many segments */
        if (nseg > ctx->re_maxsegs) {
                ctx->re_maxsegs = 0;
                return;
        }

        /*
         * Map the segment array into descriptors. Note that we set the
         * start-of-frame and end-of-frame markers for either TX or RX, but
         * they really only have meaning in the TX case. (In the RX case,
         * it's the chip that tells us where packets begin and end.)
         * 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. (The caller will
         * set this descriptor later when it start transmission or
         * reception.)
         */
        idx = ctx->re_idx;
        for (;;) {
                d = &ctx->re_ring[idx];
                if (le32toh(d->re_cmdstat) & RE_RDESC_STAT_OWN) {
                        ctx->re_maxsegs = 0;
                        return;
                }
                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 == (RE_RX_DESC_CNT - 1))
                        cmdstat |= RE_TDESC_CMD_EOR;
                d->re_cmdstat = htole32(cmdstat | ctx->re_flags);
                i++;
                if (i == nseg)
                        break;
                RE_DESC_INC(idx);
        }

        d->re_cmdstat |= htole32(RE_TDESC_CMD_EOF);
        ctx->re_maxsegs = nseg;
        ctx->re_idx = idx;
}

/*
 * Map a single buffer address.
 */

static void
re_dma_map_addr(void *arg, bus_dma_segment_t *segs, int nseg, int error)
{
        uint32_t *addr;

        if (error)
                return;

        KASSERT(nseg == 1, ("too many DMA segments, %d should be 1", nseg));
        addr = arg;
        *addr = segs->ds_addr;
}

static int
re_allocmem(device_t dev, struct re_softc *sc)
{
        int error, i, nseg;

        /*
         * Allocate map for RX mbufs.
         */
        nseg = 32;
        error = bus_dma_tag_create(sc->re_parent_tag, ETHER_ALIGN, 0,
            BUS_SPACE_MAXADDR_32BIT, BUS_SPACE_MAXADDR, NULL,
            NULL, MCLBYTES * nseg, nseg, MCLBYTES, BUS_DMA_ALLOCNOW,
            &sc->re_ldata.re_mtag);
        if (error) {
                device_printf(dev, "could not allocate dma tag\n");
                return(error);
        }

        /*
         * Allocate map for TX descriptor list.
         */
        error = bus_dma_tag_create(sc->re_parent_tag, RE_RING_ALIGN,
            0, BUS_SPACE_MAXADDR_32BIT, BUS_SPACE_MAXADDR, NULL,
            NULL, RE_TX_LIST_SZ, 1, RE_TX_LIST_SZ, BUS_DMA_ALLOCNOW,
            &sc->re_ldata.re_tx_list_tag);
        if (error) {
                device_printf(dev, "could not allocate dma tag\n");
                return(error);
        }

        /* Allocate DMA'able memory for the TX ring */

        error = bus_dmamem_alloc(sc->re_ldata.re_tx_list_tag,
            (void **)&sc->re_ldata.re_tx_list, BUS_DMA_WAITOK | BUS_DMA_ZERO,
            &sc->re_ldata.re_tx_list_map);
        if (error) {
                device_printf(dev, "could not allocate TX ring\n");
                return(error);
        }

        /* Load the map for the TX ring. */

        error = bus_dmamap_load(sc->re_ldata.re_tx_list_tag,
             sc->re_ldata.re_tx_list_map, sc->re_ldata.re_tx_list,
             RE_TX_LIST_SZ, re_dma_map_addr,
             &sc->re_ldata.re_tx_list_addr, BUS_DMA_NOWAIT);
        if (error) {
                device_printf(dev, "could not get addres of TX ring\n");
                return(error);
        }

        /* Create DMA maps for TX buffers */

        for (i = 0; i < RE_TX_DESC_CNT; i++) {
                error = bus_dmamap_create(sc->re_ldata.re_mtag, 0,
                            &sc->re_ldata.re_tx_dmamap[i]);
                if (error) {
                        device_printf(dev, "can't create DMA map for TX\n");
                        return(error);
                }
        }

        /*
         * Allocate map for RX descriptor list.
         */
        error = bus_dma_tag_create(sc->re_parent_tag, RE_RING_ALIGN,
            0, BUS_SPACE_MAXADDR_32BIT, BUS_SPACE_MAXADDR, NULL,
            NULL, RE_RX_LIST_SZ, 1, RE_RX_LIST_SZ, BUS_DMA_ALLOCNOW,
            &sc->re_ldata.re_rx_list_tag);
        if (error) {
                device_printf(dev, "could not allocate dma tag\n");
                return(error);
        }

        /* Allocate DMA'able memory for the RX ring */

        error = bus_dmamem_alloc(sc->re_ldata.re_rx_list_tag,
            (void **)&sc->re_ldata.re_rx_list, BUS_DMA_WAITOK | BUS_DMA_ZERO,
            &sc->re_ldata.re_rx_list_map);
        if (error) {
                device_printf(dev, "could not allocate RX ring\n");
                return(error);
        }

        /* Load the map for the RX ring. */

        error = bus_dmamap_load(sc->re_ldata.re_rx_list_tag,
             sc->re_ldata.re_rx_list_map, sc->re_ldata.re_rx_list,
             RE_RX_LIST_SZ, re_dma_map_addr,
             &sc->re_ldata.re_rx_list_addr, BUS_DMA_NOWAIT);
        if (error) {
                device_printf(dev, "could not get address of RX ring\n");
                return(error);
        }

        /* Create DMA maps for RX buffers */

        for (i = 0; i < RE_RX_DESC_CNT; i++) {
                error = bus_dmamap_create(sc->re_ldata.re_mtag, 0,
                            &sc->re_ldata.re_rx_dmamap[i]);
                if (error) {
                        device_printf(dev, "can't create DMA map for RX\n");
                        return(ENOMEM);
                }
        }

        return(0);
}

/*
 * 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;
        const struct re_hwrev *hw_rev;
        uint8_t eaddr[ETHER_ADDR_LEN];
        uint16_t as[ETHER_ADDR_LEN / 2];
        uint16_t re_did = 0;
        uint32_t hwrev;
        int error = 0, rid, i;

        callout_init(&sc->re_timer);
#ifdef RE_DIAG
        sc->re_dev = dev;
#endif

        RE_ENABLE_TX_MODERATION(sc);

        sysctl_ctx_init(&sc->re_sysctl_ctx);
        sc->re_sysctl_tree = SYSCTL_ADD_NODE(&sc->re_sysctl_ctx,
                                             SYSCTL_STATIC_CHILDREN(_hw),
                                             OID_AUTO,
                                             device_get_nameunit(dev),
                                             CTLFLAG_RD, 0, "");
        if (sc->re_sysctl_tree == NULL) {
                device_printf(dev, "can't add sysctl node\n");
                error = ENXIO;
                goto fail;
        }
        SYSCTL_ADD_PROC(&sc->re_sysctl_ctx,
                        SYSCTL_CHILDREN(sc->re_sysctl_tree),
                        OID_AUTO, "tx_moderation",
                        CTLTYPE_INT | CTLFLAG_RW,
                        sc, 0, re_sysctl_tx_moderation, "I",
                        "Enable/Disable TX moderation");

#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);

        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\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 */
        rid = 0;
        sc->re_irq = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
                                            RF_SHAREABLE | RF_ACTIVE);

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

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

        hwrev = CSR_READ_4(sc, RE_TXCFG) & RE_TXCFG_HWREV;
        for (hw_rev = re_hwrevs; hw_rev->re_desc != NULL; hw_rev++) {
                if (hw_rev->re_rev == hwrev) {
                        sc->re_type = hw_rev->re_type;
                        sc->re_flags = hw_rev->re_flags;
                        break;
                }
        }

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

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

        if (sc->re_type == RE_8169) {
                /* 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 the parent bus DMA tag appropriate for PCI.
         */
#define RE_NSEG_NEW 32
        error = bus_dma_tag_create(NULL,        /* parent */
                        1, 0,                   /* alignment, boundary */
                        BUS_SPACE_MAXADDR_32BIT,/* lowaddr */
                        BUS_SPACE_MAXADDR,      /* highaddr */
                        NULL, NULL,             /* filter, filterarg */
                        MAXBSIZE, RE_NSEG_NEW,  /* maxsize, nsegments */
                        BUS_SPACE_MAXSIZE_32BIT,/* maxsegsize */
                        BUS_DMA_ALLOCNOW,       /* flags */
                        &sc->re_parent_tag);
        if (error)
                goto fail;

        error = re_allocmem(dev, sc);

        if (error)
                goto fail;

        /* 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_mtu = ETHERMTU;
        ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
        ifp->if_ioctl = re_ioctl;
        ifp->if_capabilities = IFCAP_VLAN_MTU;
        ifp->if_start = re_start;
        ifp->if_capabilities |= IFCAP_HWCSUM|IFCAP_VLAN_HWTAGGING;
#ifdef DEVICE_POLLING
        ifp->if_poll = re_poll;
#endif
        ifp->if_watchdog = re_watchdog;
        ifp->if_init = re_init;
        if (sc->re_type == RE_8169)
                ifp->if_baudrate = 1000000000;
        else
                ifp->if_baudrate = 100000000;
        ifq_set_maxlen(&ifp->if_snd, RE_IFQ_MAXLEN);
        ifq_set_ready(&ifp->if_snd);

#ifdef RE_DISABLE_HWCSUM
        ifp->if_capenable = ifp->if_capabilities & ~IFCAP_HWCSUM;
        ifp->if_hwassist = 0;
#else
        ifp->if_capenable = ifp->if_capabilities;
        ifp->if_hwassist = RE_CSUM_FEATURES;
#endif  /* RE_DISABLE_HWCSUM */

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

#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 (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_NETSAFE, 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;
        int i;

        /* 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, 0, sc->re_irq);
        if (sc->re_res) {
                bus_release_resource(dev, SYS_RES_IOPORT, RE_PCI_LOIO,
                                     sc->re_res);
        }

        /* 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);
        }

        /* Destroy all the RX and TX buffer maps */

        if (sc->re_ldata.re_mtag) {
                for (i = 0; i < RE_TX_DESC_CNT; i++)
                        bus_dmamap_destroy(sc->re_ldata.re_mtag,
                            sc->re_ldata.re_tx_dmamap[i]);
                for (i = 0; i < RE_RX_DESC_CNT; i++)
                        bus_dmamap_destroy(sc->re_ldata.re_mtag,
                            sc->re_ldata.re_rx_dmamap[i]);
                bus_dma_tag_destroy(sc->re_ldata.re_mtag);
        }

        /* 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_rx_list_map);
                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_parent_tag)
                bus_dma_tag_destroy(sc->re_parent_tag);

        return(0);
}

static int
re_newbuf(struct re_softc *sc, int idx, struct mbuf *m)
{
        struct re_dmaload_arg arg;
        struct mbuf *n = NULL;
        int error;

        if (m == NULL) {
                n = m_getcl(MB_DONTWAIT, MT_DATA, M_PKTHDR);
                if (n == NULL)
                        return(ENOBUFS);
                m = n;
        } else
                m->m_data = m->m_ext.ext_buf;

        m->m_len = m->m_pkthdr.len = MCLBYTES;

        /*
         * 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.
         */

        arg.sc = sc;
        arg.re_idx = idx;
        arg.re_maxsegs = 1;
        arg.re_flags = 0;
        arg.re_ring = sc->re_ldata.re_rx_list;

        error = bus_dmamap_load_mbuf(sc->re_ldata.re_mtag,
            sc->re_ldata.re_rx_dmamap[idx], m, re_dma_map_desc,
            &arg, BUS_DMA_NOWAIT);
        if (error || arg.re_maxsegs != 1) {
                if (n != NULL)
                        m_freem(n);
                return (ENOMEM);
        }

        sc->re_ldata.re_rx_list[idx].re_cmdstat |= htole32(RE_RDESC_CMD_OWN);
        sc->re_ldata.re_rx_mbuf[idx] = m;

        bus_dmamap_sync(sc->re_ldata.re_mtag, sc->re_ldata.re_rx_dmamap[idx],
                        BUS_DMASYNC_PREREAD);

        return(0);
}

static int
re_tx_list_init(struct re_softc *sc)
{
        bzero(sc->re_ldata.re_tx_list, RE_TX_LIST_SZ);
        bzero(&sc->re_ldata.re_tx_mbuf, RE_TX_DESC_CNT * sizeof(struct mbuf *));

        bus_dmamap_sync(sc->re_ldata.re_tx_list_tag,
                        sc->re_ldata.re_tx_list_map, BUS_DMASYNC_PREWRITE);
        sc->re_ldata.re_tx_prodidx = 0;
        sc->re_ldata.re_tx_considx = 0;
        sc->re_ldata.re_tx_free = 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);
        bzero(&sc->re_ldata.re_rx_mbuf, RE_RX_DESC_CNT * sizeof(struct mbuf *));

        for (i = 0; i < RE_RX_DESC_CNT; i++) {
                error = re_newbuf(sc, i, NULL);
                if (error)
                        return(error);
        }

        /* Flush the RX descriptors */

        bus_dmamap_sync(sc->re_ldata.re_rx_list_tag,
                        sc->re_ldata.re_rx_list_map, BUS_DMASYNC_PREWRITE);

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

        return(0);
}

/*
 * 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 void
re_rxeof(struct re_softc *sc)
{
        struct ifnet *ifp = &sc->arpcom.ac_if;
        struct mbuf *m;
        struct re_desc  *cur_rx;
        uint32_t rxstat, rxvlan;
        int i, total_len;

        /* Invalidate the descriptor memory */

        bus_dmamap_sync(sc->re_ldata.re_rx_list_tag,
                        sc->re_ldata.re_rx_list_map, BUS_DMASYNC_POSTREAD);

        for (i = sc->re_ldata.re_rx_prodidx;
             RE_OWN(&sc->re_ldata.re_rx_list[i]) == 0 ; RE_DESC_INC(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);
                rxvlan = le32toh(cur_rx->re_vlanctl);

                /* Invalidate the RX mbuf and unload its map */

                bus_dmamap_sync(sc->re_ldata.re_mtag,
                                sc->re_ldata.re_rx_dmamap[i],
                                BUS_DMASYNC_POSTWRITE);
                bus_dmamap_unload(sc->re_ldata.re_mtag,
                                  sc->re_ldata.re_rx_dmamap[i]);

                if ((rxstat & RE_RDESC_STAT_EOF) == 0) {
                        m->m_len = MCLBYTES - ETHER_ALIGN;
                        if (sc->re_head == NULL) {
                                sc->re_head = sc->re_tail = m;
                        } else {
                                sc->re_tail->m_next = m;
                                sc->re_tail = m;
                        }
                        re_newbuf(sc, i, NULL);
                        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 (sc->re_type == RE_8169)
                        rxstat >>= 1;

                if (rxstat & RE_RDESC_STAT_RXERRSUM) {
                        ifp->if_ierrors++;
                        /*
                         * If this is part of a multi-fragment packet,
                         * discard all the pieces.
                         */
                        if (sc->re_head != NULL) {
                                m_freem(sc->re_head);
                                sc->re_head = sc->re_tail = NULL;
                        }
                        re_newbuf(sc, i, m);
                        continue;
                }

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

                if (re_newbuf(sc, i, NULL)) {
                        ifp->if_ierrors++;
                        if (sc->re_head != NULL) {
                                m_freem(sc->re_head);
                                sc->re_head = sc->re_tail = NULL;
                        }
                        re_newbuf(sc, i, m);
                        continue;
                }

                if (sc->re_head != NULL) {
                        m->m_len = total_len % (MCLBYTES - ETHER_ALIGN);
                        /* 
                         * 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);

                ifp->if_ipackets++;
                m->m_pkthdr.rcvif = ifp;

                /* Do RX checksumming if enabled */

                if (ifp->if_capenable & IFCAP_RXCSUM) {

                        /* Check IP header checksum */
                        if (rxstat & RE_RDESC_STAT_PROTOID)
                                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 ((RE_TCPPKT(rxstat) &&
                            (rxstat & RE_RDESC_STAT_TCPSUMBAD) == 0) ||
                            (RE_UDPPKT(rxstat) &&
                            (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 (rxvlan & RE_RDESC_VLANCTL_TAG) {
                        VLAN_INPUT_TAG(m,
                           be16toh((rxvlan & RE_RDESC_VLANCTL_DATA)));
                } else {
                        ifp->if_input(ifp, m);
                }
        }

        /* Flush the RX DMA ring */

        bus_dmamap_sync(sc->re_ldata.re_rx_list_tag,
                        sc->re_ldata.re_rx_list_map, BUS_DMASYNC_PREWRITE);

        sc->re_ldata.re_rx_prodidx = i;
}

static void
re_txeof(struct re_softc *sc)
{
        struct ifnet *ifp = &sc->arpcom.ac_if;
        uint32_t txstat;
        int idx;

        /* Invalidate the TX descriptor list */

        bus_dmamap_sync(sc->re_ldata.re_tx_list_tag,
                        sc->re_ldata.re_tx_list_map, BUS_DMASYNC_POSTREAD);

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

                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) {
                        m_freem(sc->re_ldata.re_tx_mbuf[idx]);
                        sc->re_ldata.re_tx_mbuf[idx] = NULL;
                        bus_dmamap_unload(sc->re_ldata.re_mtag,
                            sc->re_ldata.re_tx_dmamap[idx]);
                        if (txstat & (RE_TDESC_STAT_EXCESSCOL|
                            RE_TDESC_STAT_COLCNT))
                                ifp->if_collisions++;
                        if (txstat & RE_TDESC_STAT_TXERRSUM)
                                ifp->if_oerrors++;
                        else
                                ifp->if_opackets++;
                }
                sc->re_ldata.re_tx_free++;
        }

        /* No changes made to the TX ring, so no flush needed */
        if (sc->re_ldata.re_tx_free) {
                sc->re_ldata.re_tx_considx = idx;
                ifp->if_flags &= ~IFF_OACTIVE;
                ifp->if_timer = 0;
        }

        /*
         * 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 < RE_TX_DESC_CNT)
                CSR_WRITE_1(sc, sc->re_txstart, RE_TXSTART_START);

        /*
         * If not all descriptors have been released reaped yet,
         * reload the timer so that we will eventually get another
         * interrupt that will cause us to re-enter this routine.
         * This is done in case the transmitter has gone idle.
         */
        if (RE_TX_MODERATION_IS_ENABLED(sc) &&
            sc->re_ldata.re_tx_free < RE_TX_DESC_CNT)
                CSR_WRITE_4(sc, RE_TIMERCNT, 1);
}

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;

        mii = device_get_softc(sc->re_miibus);
        mii_tick(mii);
        if (sc->re_link) {
                if (!(mii->mii_media_status & IFM_ACTIVE))
                        sc->re_link = 0;
        } else {
                if (mii->mii_media_status & IFM_ACTIVE &&
                    IFM_SUBTYPE(mii->mii_media_active) != IFM_NONE) {
                        sc->re_link = 1;
                        if (!ifq_is_empty(&ifp->if_snd))
                                ifp->if_start(ifp);
                }
        }

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

#ifdef DEVICE_POLLING

static void
re_poll(struct ifnet *ifp, enum poll_cmd cmd, int count)
{
        struct re_softc *sc = ifp->if_softc;

        switch(cmd) {
        case POLL_REGISTER:
                /* disable interrupts */
                CSR_WRITE_2(sc, RE_IMR, 0x0000);
                break;
        case POLL_DEREGISTER:
                /* enable interrupts */
                CSR_WRITE_2(sc, RE_IMR, sc->re_intrs);
                break;
        default:
                sc->rxcycles = count;
                re_rxeof(sc);
                re_txeof(sc);

                if (!ifq_is_empty(&ifp->if_snd))
                        (*ifp->if_start)(ifp);

                if (cmd == POLL_AND_CHECK_STATUS) { /* also check status register */
                        uint16_t       status;

                        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_reset(sc);
                                re_init(sc);
                        }
                }
                break;
        }
}
#endif /* DEVICE_POLLING */

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

        if (sc->suspended || (ifp->if_flags & IFF_UP) == 0)
                return;

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

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

                if (status & (RE_ISR_RX_OK | RE_ISR_RX_ERR | RE_ISR_FIFO_OFLOW))
                        re_rxeof(sc);

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

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

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

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

static int
re_encap(struct re_softc *sc, struct mbuf **m_head, int *idx, int *called_defrag)
{
        struct ifnet *ifp = &sc->arpcom.ac_if;
        struct mbuf *m, *m_new = NULL;
        struct re_dmaload_arg   arg;
        bus_dmamap_t            map;
        int                     error;

        *called_defrag = 0;
        if (sc->re_ldata.re_tx_free <= 4)
                return(EFBIG);

        m = *m_head;

        /*
         * 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.)
         */

        arg.re_flags = 0;

        if (m->m_pkthdr.csum_flags & CSUM_IP)
                arg.re_flags |= RE_TDESC_CMD_IPCSUM;
        if (m->m_pkthdr.csum_flags & CSUM_TCP)
                arg.re_flags |= RE_TDESC_CMD_TCPCSUM;
        if (m->m_pkthdr.csum_flags & CSUM_UDP)
                arg.re_flags |= RE_TDESC_CMD_UDPCSUM;

        arg.sc = sc;
        arg.re_idx = *idx;
        arg.re_maxsegs = sc->re_ldata.re_tx_free;
        if (arg.re_maxsegs > 4)
                arg.re_maxsegs -= 4;
        arg.re_ring = sc->re_ldata.re_tx_list;

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

        /*
         * 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. We do this by pretending
         * the mbuf chain has too many fragments so the coalescing code
         * below can assemble the packet into a single buffer that's
         * padded out to the mininum frame size.
         *
         * Note: this appears unnecessary for TCP, and doing it for TCP
         * with PCIe adapters seems to result in bad checksums.
         */
        if (arg.re_flags && !(arg.re_flags & RE_TDESC_CMD_TCPCSUM) &&
            m->m_pkthdr.len < RE_MIN_FRAMELEN) {
                error = EFBIG;
        } else {
                error = bus_dmamap_load_mbuf(sc->re_ldata.re_mtag, map,
                    m, re_dma_map_desc, &arg, BUS_DMA_NOWAIT);
        }

        if (error && error != EFBIG) {
                if_printf(ifp, "can't map mbuf (error %d)\n", error);
                return(ENOBUFS);
        }

        /* Too many segments to map, coalesce into a single mbuf */

        if (error || arg.re_maxsegs == 0) {
                m_new = m_defrag_nofree(m, MB_DONTWAIT);
                if (m_new == NULL) {
                        return(1);
                } else {
                        m = m_new;
                        *m_head = m;
                }

                /*
                 * Manually pad short frames, and zero the pad space
                 * to avoid leaking data.
                 */
                if (m_new->m_pkthdr.len < RE_MIN_FRAMELEN) {
                        bzero(mtod(m_new, char *) + m_new->m_pkthdr.len,
                            RE_MIN_FRAMELEN - m_new->m_pkthdr.len);
                        m_new->m_pkthdr.len += RE_MIN_FRAMELEN -
                            m_new->m_pkthdr.len;
                        m_new->m_len = m_new->m_pkthdr.len;
                }

                *called_defrag = 1;
                arg.sc = sc;
                arg.re_idx = *idx;
                arg.re_maxsegs = sc->re_ldata.re_tx_free;
                arg.re_ring = sc->re_ldata.re_tx_list;

                error = bus_dmamap_load_mbuf(sc->re_ldata.re_mtag, map,
                    m, re_dma_map_desc, &arg, BUS_DMA_NOWAIT);
                if (error) {
                        m_freem(m);
                        if_printf(ifp, "can't map mbuf (error %d)\n", error);
                        return(EFBIG);
                }
        }

        /*
         * 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[*idx] =
            sc->re_ldata.re_tx_dmamap[arg.re_idx];
        sc->re_ldata.re_tx_dmamap[arg.re_idx] = map;

        sc->re_ldata.re_tx_mbuf[arg.re_idx] = m;
        sc->re_ldata.re_tx_free -= arg.re_maxsegs;

        /*
         * Set up hardware VLAN tagging. Note: vlan tag info must
         * appear in the first descriptor of a multi-descriptor
         * transmission attempt.
         */

        if ((m->m_flags & (M_PROTO1|M_PKTHDR)) == (M_PROTO1|M_PKTHDR) &&
            m->m_pkthdr.rcvif != NULL &&
            m->m_pkthdr.rcvif->if_type == IFT_L2VLAN) {
                struct ifvlan *ifv;
                ifv = m->m_pkthdr.rcvif->if_softc;
                if (ifv != NULL)
                        sc->re_ldata.re_tx_list[*idx].re_vlanctl =
                            htole32(htobe16(ifv->ifv_tag) | RE_TDESC_VLANCTL_TAG);
        }

        /* Transfer ownership of packet to the chip. */

        sc->re_ldata.re_tx_list[arg.re_idx].re_cmdstat |=
            htole32(RE_TDESC_CMD_OWN);
        if (*idx != arg.re_idx)
                sc->re_ldata.re_tx_list[*idx].re_cmdstat |=
                    htole32(RE_TDESC_CMD_OWN);

        RE_DESC_INC(arg.re_idx);
        *idx = arg.re_idx;

        return(0);
}

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

static void
re_start(struct ifnet *ifp)
{
        struct re_softc *sc = ifp->if_softc;
        struct mbuf *m_head;
        struct mbuf *m_head2;
        int called_defrag, idx, need_trans;

        if (!sc->re_link || (ifp->if_flags & IFF_OACTIVE))
                return;

        idx = sc->re_ldata.re_tx_prodidx;

        need_trans = 0;
        while (sc->re_ldata.re_tx_mbuf[idx] == NULL) {
                m_head = ifq_poll(&ifp->if_snd);
                if (m_head == NULL)
                        break;
                m_head2 = m_head;
                if (re_encap(sc, &m_head2, &idx, &called_defrag)) {
                        /*
                         * If we could not encapsulate the defragged packet,
                         * the returned m_head2 is garbage and we must dequeue
                         * and throw away the original packet.
                         */
                        if (called_defrag) {
                                ifq_dequeue(&ifp->if_snd, m_head);
                                m_freem(m_head);
                        }
                        ifp->if_flags |= IFF_OACTIVE;
                        break;
                }

                /*
                 * Clean out the packet we encapsulated.  If we defragged
                 * the packet the m_head2 is the one that got encapsulated
                 * and the original must be thrown away.  Otherwise m_head2
                 * *IS* the original.
                 */
                ifq_dequeue(&ifp->if_snd, m_head);
                if (called_defrag)
                        m_freem(m_head);
                need_trans = 1;

                /*
                 * If there's a BPF listener, bounce a copy of this frame
                 * to him.
                 */
                BPF_MTAP(ifp, m_head2);
        }

        if (!need_trans) {
                if (RE_TX_MODERATION_IS_ENABLED(sc) &&
                    sc->re_ldata.re_tx_free != RE_TX_DESC_CNT)
                        CSR_WRITE_4(sc, RE_TIMERCNT, 1);
                return;
        }

        /* Flush the TX descriptors */
        bus_dmamap_sync(sc->re_ldata.re_tx_list_tag,
                        sc->re_ldata.re_tx_list_map, BUS_DMASYNC_PREWRITE);

        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);

        if (RE_TX_MODERATION_IS_ENABLED(sc)) {
                /*
                 * Use the countdown timer for interrupt moderation.
                 * 'TX done' interrupts are disabled. Instead, we reset the
                 * countdown timer, which will begin counting until it hits
                 * the value in the TIMERINT register, and then trigger an
                 * interrupt. Each time we write to the TIMERCNT register,
                 * the timer count is reset to 0.
                 */
                CSR_WRITE_4(sc, RE_TIMERCNT, 1);
        }

        /*
         * 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;
        uint32_t rxcfg = 0;

        mii = device_get_softc(sc->re_miibus);

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

        /*
         * 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 | RE_CPLUSCMD_VLANSTRIP |
                    (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.
         */
        re_rx_list_init(sc);
        re_tx_list_init(sc);

        /*
         * 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_testmode) {
                if (sc->re_type == RE_8169)
                        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);

        CSR_WRITE_1(sc, RE_EARLY_TX_THRESH, 16);

        CSR_WRITE_4(sc, RE_RXCFG, RE_RXCFG_CONFIG);

        /* Set the individual bit to receive frames for this host only. */
        rxcfg = CSR_READ_4(sc, RE_RXCFG);
        rxcfg |= RE_RXCFG_RX_INDIV;

        /* If we want promiscuous mode, set the allframes bit. */
        if (ifp->if_flags & IFF_PROMISC) {
                rxcfg |= RE_RXCFG_RX_ALLPHYS;
                CSR_WRITE_4(sc, RE_RXCFG, rxcfg);
        } else {
                rxcfg &= ~RE_RXCFG_RX_ALLPHYS;
                CSR_WRITE_4(sc, RE_RXCFG, rxcfg);
        }

        /*
         * Set capture broadcast bit to capture broadcast frames.
         */
        if (ifp->if_flags & IFF_BROADCAST) {
                rxcfg |= RE_RXCFG_RX_BROAD;
                CSR_WRITE_4(sc, RE_RXCFG, rxcfg);
        } else {
                rxcfg &= ~RE_RXCFG_RX_BROAD;
                CSR_WRITE_4(sc, RE_RXCFG, rxcfg);
        }

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

#ifdef DEVICE_POLLING
        /*
         * Disable interrupts if we are polling.
         */
        if (ifp->if_flags & IFF_POLLING)
                CSR_WRITE_2(sc, RE_IMR, 0);
        else    /* otherwise ... */
#endif /* DEVICE_POLLING */
        /*
         * Enable interrupts.
         */
        if (sc->re_testmode)
                CSR_WRITE_2(sc, RE_IMR, 0);
        else
                CSR_WRITE_2(sc, RE_IMR, sc->re_intrs);
        CSR_WRITE_2(sc, RE_ISR, sc->re_intrs);

        /* Set initial TX threshold */
        sc->re_txthresh = RE_TX_THRESH_INIT;

        /* Start RX/TX process. */
        if (sc->re_flags & RE_F_HASMPC)
                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

        if (RE_TX_MODERATION_IS_ENABLED(sc)) {
                /*
                 * Initialize the timer interrupt register so that
                 * a timer interrupt will be generated once the timer
                 * reaches a certain number of ticks. The timer is
                 * reloaded on each transmit. This gives us TX interrupt
                 * moderation, which dramatically improves TX frame rate.
                 */
                if (sc->re_type == RE_8169)
                        CSR_WRITE_4(sc, RE_TIMERINT_8169, 0x800);
                else
                        CSR_WRITE_4(sc, RE_TIMERINT, 0x400);
        }

        /*
         * For 8169 gigE NICs, set the max allowed RX packet
         * size so we can receive jumbo frames.
         */
        if (sc->re_type == RE_8169)
                CSR_WRITE_2(sc, RE_MAXRXPKTLEN, 16383);

        if (sc->re_testmode) {
                return;
        }

        mii_mediachg(mii);

        CSR_WRITE_1(sc, RE_CFG1, RE_CFG1_DRVLOAD|RE_CFG1_FULLDUPLEX);

        ifp->if_flags |= IFF_RUNNING;
        ifp->if_flags &= ~IFF_OACTIVE;

        sc->re_link = 0;
        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;

        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;

        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;

        switch(command) {
        case SIOCSIFMTU:
                if (ifr->ifr_mtu > RE_JUMBO_MTU)
                        error = EINVAL;
                ifp->if_mtu = ifr->ifr_mtu;
                break;
        case SIOCSIFFLAGS:
                if (ifp->if_flags & IFF_UP)
                        re_init(sc);
                else if (ifp->if_flags & IFF_RUNNING)
                        re_stop(sc);
                break;
        case SIOCADDMULTI:
        case SIOCDELMULTI:
                re_setmulti(sc);
                error = 0;
                break;
        case SIOCGIFMEDIA:
        case SIOCSIFMEDIA:
                mii = device_get_softc(sc->re_miibus);
                error = ifmedia_ioctl(ifp, ifr, &mii->mii_media, command);
                break;
        case SIOCSIFCAP:
                ifp->if_capenable &= ~(IFCAP_HWCSUM);
                ifp->if_capenable |=
                    ifr->ifr_reqcap & (IFCAP_HWCSUM);
                if (ifp->if_capenable & IFCAP_TXCSUM)
                        ifp->if_hwassist = RE_CSUM_FEATURES;
                else
                        ifp->if_hwassist = 0;
                if (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;

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

        ifp->if_oerrors++;

        re_txeof(sc);
        re_rxeof(sc);

        re_init(sc);

        if (!ifq_is_empty(&ifp->if_snd))
                ifp->if_start(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;

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

        ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);

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

        if (sc->re_head != NULL) {
                m_freem(sc->re_head);
                sc->re_head = sc->re_tail = NULL;
        }

        /* Free the TX list buffers. */
        for (i = 0; i < RE_TX_DESC_CNT; i++) {
                if (sc->re_ldata.re_tx_mbuf[i] != NULL) {
                        bus_dmamap_unload(sc->re_ldata.re_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 < RE_RX_DESC_CNT; i++) {
                if (sc->re_ldata.re_rx_mbuf[i] != NULL) {
                        bus_dmamap_unload(sc->re_ldata.re_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);

        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->suspended = 1;

        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

#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->suspended = 0;

        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_tx_moderation(SYSCTL_HANDLER_ARGS)
{
        struct re_softc *sc = arg1;
        struct ifnet *ifp = &sc->arpcom.ac_if;
        int error = 0, mod, mod_old;

        lwkt_serialize_enter(ifp->if_serializer);

        mod_old = mod = RE_TX_MODERATION_IS_ENABLED(sc);

        error = sysctl_handle_int(oidp, &mod, 0, req);
        if (error || req->newptr == NULL || mod == mod_old)
                goto back;
        if (mod != 0 && mod != 1) {
                error = EINVAL;
                goto back;
        }

        if (mod)
                RE_ENABLE_TX_MODERATION(sc);
        else
                RE_DISABLE_TX_MODERATION(sc);

        if ((ifp->if_flags & (IFF_RUNNING | IFF_UP)) == (IFF_RUNNING | IFF_UP))
                re_init(sc);
back:
        lwkt_serialize_exit(ifp->if_serializer);
        return error;
}