FreeBSD/Linux Kernel Cross Reference
sys/dev/fxp/if_fxp.c

     /*-
      * Copyright (c) 1995, David Greenman
      * Copyright (c) 2001 Jonathan Lemon <jlemon@freebsd.org>
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
     *    notice unmodified, this list of conditions, and the following
     *    disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 THE AUTHOR OR CONTRIBUTORS 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.
     *
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    /*
     * Intel EtherExpress Pro/100B PCI Fast Ethernet driver
     */
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/endian.h>
    #include <sys/mbuf.h>
                    /* #include <sys/mutex.h> */
    #include <sys/kernel.h>
    #include <sys/module.h>
    #include <sys/socket.h>
    #include <sys/sysctl.h>
    
    #include <net/if.h>
    #include <net/if_dl.h>
    #include <net/if_media.h>
    
    #include <net/bpf.h>
    #include <sys/sockio.h>
    #include <sys/bus.h>
    #include <machine/bus.h>
    #include <sys/rman.h>
    #include <machine/resource.h>
    
    #include <net/ethernet.h>
    #include <net/if_arp.h>
    
    #include <machine/clock.h>      /* for DELAY */
    
    #include <net/if_types.h>
    #include <net/if_vlan_var.h>
    
    #ifdef FXP_IP_CSUM_WAR
    #include <netinet/in.h>
    #include <netinet/in_systm.h>
    #include <netinet/ip.h>
    #include <machine/in_cksum.h>
    #endif
    
    #include <dev/pci/pcivar.h>
    #include <dev/pci/pcireg.h>             /* for PCIM_CMD_xxx */
    
    #include <dev/mii/mii.h>
    #include <dev/mii/miivar.h>
    
    #include <dev/fxp/if_fxpreg.h>
    #include <dev/fxp/if_fxpvar.h>
    #include <dev/fxp/rcvbundl.h>
    
    MODULE_DEPEND(fxp, pci, 1, 1, 1);
    MODULE_DEPEND(fxp, ether, 1, 1, 1);
    MODULE_DEPEND(fxp, miibus, 1, 1, 1);
    #include "miibus_if.h"
    
    /*
     * NOTE!  On the Alpha, we have an alignment constraint.  The
     * card DMAs the packet immediately following the RFA.  However,
     * the first thing in the packet is a 14-byte Ethernet header.
     * This means that the packet is misaligned.  To compensate,
     * we actually offset the RFA 2 bytes into the cluster.  This
     * alignes the packet after the Ethernet header at a 32-bit
     * boundary.  HOWEVER!  This means that the RFA is misaligned!
     */
    #define RFA_ALIGNMENT_FUDGE     2
    
    /*
    * Set initial transmit threshold at 64 (512 bytes). This is
    * increased by 64 (512 bytes) at a time, to maximum of 192
    * (1536 bytes), if an underrun occurs.
    */
   static int tx_threshold = 64;
   
   /*
    * The configuration byte map has several undefined fields which
    * must be one or must be zero.  Set up a template for these bits
    * only, (assuming a 82557 chip) leaving the actual configuration
    * to fxp_init.
    *
    * See struct fxp_cb_config for the bit definitions.
    */
   static u_char fxp_cb_config_template[] = {
           0x0, 0x0,               /* cb_status */
           0x0, 0x0,               /* cb_command */
           0x0, 0x0, 0x0, 0x0,     /* link_addr */
           0x0,    /*  0 */
           0x0,    /*  1 */
           0x0,    /*  2 */
           0x0,    /*  3 */
           0x0,    /*  4 */
           0x0,    /*  5 */
           0x32,   /*  6 */
           0x0,    /*  7 */
           0x0,    /*  8 */
           0x0,    /*  9 */
           0x6,    /* 10 */
           0x0,    /* 11 */
           0x0,    /* 12 */
           0x0,    /* 13 */
           0xf2,   /* 14 */
           0x48,   /* 15 */
           0x0,    /* 16 */
           0x40,   /* 17 */
           0xf0,   /* 18 */
           0x0,    /* 19 */
           0x3f,   /* 20 */
           0x5     /* 21 */
   };
   
   struct fxp_ident {
           uint16_t        devid;
           int16_t         revid;          /* -1 matches anything */
           char            *name;
   };
   
   /*
    * Claim various Intel PCI device identifiers for this driver.  The
    * sub-vendor and sub-device field are extensively used to identify
    * particular variants, but we don't currently differentiate between
    * them.
    */
   static struct fxp_ident fxp_ident_table[] = {
       { 0x1029,   -1,     "Intel 82559 PCI/CardBus Pro/100" },
       { 0x1030,   -1,     "Intel 82559 Pro/100 Ethernet" },
       { 0x1031,   -1,     "Intel 82801CAM (ICH3) Pro/100 VE Ethernet" },
       { 0x1032,   -1,     "Intel 82801CAM (ICH3) Pro/100 VE Ethernet" },
       { 0x1033,   -1,     "Intel 82801CAM (ICH3) Pro/100 VM Ethernet" },
       { 0x1034,   -1,     "Intel 82801CAM (ICH3) Pro/100 VM Ethernet" },
       { 0x1035,   -1,     "Intel 82801CAM (ICH3) Pro/100 Ethernet" },
       { 0x1036,   -1,     "Intel 82801CAM (ICH3) Pro/100 Ethernet" },
       { 0x1037,   -1,     "Intel 82801CAM (ICH3) Pro/100 Ethernet" },
       { 0x1038,   -1,     "Intel 82801CAM (ICH3) Pro/100 VM Ethernet" },
       { 0x1039,   -1,     "Intel 82801DB (ICH4) Pro/100 VE Ethernet" },
       { 0x103A,   -1,     "Intel 82801DB (ICH4) Pro/100 Ethernet" },
       { 0x103B,   -1,     "Intel 82801DB (ICH4) Pro/100 VM Ethernet" },
       { 0x103C,   -1,     "Intel 82801DB (ICH4) Pro/100 Ethernet" },
       { 0x103D,   -1,     "Intel 82801DB (ICH4) Pro/100 VE Ethernet" },
       { 0x103E,   -1,     "Intel 82801DB (ICH4) Pro/100 VM Ethernet" },
       { 0x1050,   -1,     "Intel 82801BA (D865) Pro/100 VE Ethernet" },
       { 0x1051,   -1,     "Intel 82562ET (ICH5/ICH5R) Pro/100 VE Ethernet" },
       { 0x1059,   -1,     "Intel 82551QM Pro/100 M Mobile Connection" },
       { 0x1064,   -1,     "Intel 82562EZ (ICH6)" },
       { 0x1068,   -1,     "Intel 82801FBM (ICH6-M) Pro/100 VE Ethernet" },
       { 0x1069,   -1,     "Intel 82562EM/EX/GX Pro/100 Ethernet" },
       { 0x1209,   -1,     "Intel 82559ER Embedded 10/100 Ethernet" },
       { 0x1229,   0x01,   "Intel 82557 Pro/100 Ethernet" },
       { 0x1229,   0x02,   "Intel 82557 Pro/100 Ethernet" },
       { 0x1229,   0x03,   "Intel 82557 Pro/100 Ethernet" },
       { 0x1229,   0x04,   "Intel 82558 Pro/100 Ethernet" },
       { 0x1229,   0x05,   "Intel 82558 Pro/100 Ethernet" },
       { 0x1229,   0x06,   "Intel 82559 Pro/100 Ethernet" },
       { 0x1229,   0x07,   "Intel 82559 Pro/100 Ethernet" },
       { 0x1229,   0x08,   "Intel 82559 Pro/100 Ethernet" },
       { 0x1229,   0x09,   "Intel 82559ER Pro/100 Ethernet" },
       { 0x1229,   0x0c,   "Intel 82550 Pro/100 Ethernet" },
       { 0x1229,   0x0d,   "Intel 82550 Pro/100 Ethernet" },
       { 0x1229,   0x0e,   "Intel 82550 Pro/100 Ethernet" },
       { 0x1229,   0x0f,   "Intel 82551 Pro/100 Ethernet" },
       { 0x1229,   0x10,   "Intel 82551 Pro/100 Ethernet" },
       { 0x1229,   -1,     "Intel 82557/8/9 Pro/100 Ethernet" },
       { 0x2449,   -1,     "Intel 82801BA/CAM (ICH2/3) Pro/100 Ethernet" },
       { 0x27dc,   -1,     "Intel 82801GB (ICH7) 10/100 Ethernet" },
       { 0,        -1,     NULL },
   };
   
   #ifdef FXP_IP_CSUM_WAR
   #define FXP_CSUM_FEATURES    (CSUM_IP | CSUM_TCP | CSUM_UDP)
   #else
   #define FXP_CSUM_FEATURES    (CSUM_TCP | CSUM_UDP)
   #endif
   
   static int              fxp_probe(device_t dev);
   static int              fxp_attach(device_t dev);
   static int              fxp_detach(device_t dev);
   static int              fxp_shutdown(device_t dev);
   static int              fxp_suspend(device_t dev);
   static int              fxp_resume(device_t dev);
   
   static void             fxp_intr(void *xsc);
   static void             fxp_intr_body(struct fxp_softc *sc, struct ifnet *ifp,
                               uint8_t statack, int count);
   static void             fxp_init(void *xsc);
   static void             fxp_init_body(struct fxp_softc *sc);
   static void             fxp_tick(void *xsc);
   static void             fxp_start(struct ifnet *ifp);
   static void             fxp_start_body(struct ifnet *ifp);
   static void             fxp_stop(struct fxp_softc *sc);
   static void             fxp_release(struct fxp_softc *sc);
   static int              fxp_ioctl(struct ifnet *ifp, u_long command,
                               caddr_t data);
   static void             fxp_watchdog(struct ifnet *ifp);
   static int              fxp_add_rfabuf(struct fxp_softc *sc,
                               struct fxp_rx *rxp);
   static int              fxp_mc_addrs(struct fxp_softc *sc);
   static void             fxp_mc_setup(struct fxp_softc *sc);
   static uint16_t         fxp_eeprom_getword(struct fxp_softc *sc, int offset,
                               int autosize);
   static void             fxp_eeprom_putword(struct fxp_softc *sc, int offset,
                               uint16_t data);
   static void             fxp_autosize_eeprom(struct fxp_softc *sc);
   static void             fxp_read_eeprom(struct fxp_softc *sc, u_short *data,
                               int offset, int words);
   static void             fxp_write_eeprom(struct fxp_softc *sc, u_short *data,
                               int offset, int words);
   static int              fxp_ifmedia_upd(struct ifnet *ifp);
   static void             fxp_ifmedia_sts(struct ifnet *ifp,
                               struct ifmediareq *ifmr);
   static int              fxp_serial_ifmedia_upd(struct ifnet *ifp);
   static void             fxp_serial_ifmedia_sts(struct ifnet *ifp,
                               struct ifmediareq *ifmr);
   static volatile int     fxp_miibus_readreg(device_t dev, int phy, int reg);
   static void             fxp_miibus_writereg(device_t dev, int phy, int reg,
                               int value);
   static void             fxp_load_ucode(struct fxp_softc *sc);
   static int              sysctl_int_range(SYSCTL_HANDLER_ARGS,
                               int low, int high);
   static int              sysctl_hw_fxp_bundle_max(SYSCTL_HANDLER_ARGS);
   static int              sysctl_hw_fxp_int_delay(SYSCTL_HANDLER_ARGS);
   static void             fxp_scb_wait(struct fxp_softc *sc);
   static void             fxp_scb_cmd(struct fxp_softc *sc, int cmd);
   static void             fxp_dma_wait(struct fxp_softc *sc,
                               volatile uint16_t *status, bus_dma_tag_t dmat,
                               bus_dmamap_t map);
   
   static device_method_t fxp_methods[] = {
           /* Device interface */
           DEVMETHOD(device_probe,         fxp_probe),
           DEVMETHOD(device_attach,        fxp_attach),
           DEVMETHOD(device_detach,        fxp_detach),
           DEVMETHOD(device_shutdown,      fxp_shutdown),
           DEVMETHOD(device_suspend,       fxp_suspend),
           DEVMETHOD(device_resume,        fxp_resume),
   
           /* MII interface */
           DEVMETHOD(miibus_readreg,       fxp_miibus_readreg),
           DEVMETHOD(miibus_writereg,      fxp_miibus_writereg),
   
           { 0, 0 }
   };
   
   static driver_t fxp_driver = {
           "fxp",
           fxp_methods,
           sizeof(struct fxp_softc),
   };
   
   static devclass_t fxp_devclass;
   
   DRIVER_MODULE(fxp, pci, fxp_driver, fxp_devclass, 0, 0);
   DRIVER_MODULE(fxp, cardbus, fxp_driver, fxp_devclass, 0, 0);
   DRIVER_MODULE(miibus, fxp, miibus_driver, miibus_devclass, 0, 0);
   
   /*
    * Wait for the previous command to be accepted (but not necessarily
    * completed).
    */
   static void
   fxp_scb_wait(struct fxp_softc *sc)
   {
           int i = 10000;
   
           while (CSR_READ_1(sc, FXP_CSR_SCB_COMMAND) && --i)
                   DELAY(2);
           if (i == 0)
                   device_printf(sc->dev, "SCB timeout: 0x%x 0x%x 0x%x 0x%x\n",
                       CSR_READ_1(sc, FXP_CSR_SCB_COMMAND),
                       CSR_READ_1(sc, FXP_CSR_SCB_STATACK),
                       CSR_READ_1(sc, FXP_CSR_SCB_RUSCUS),
                       CSR_READ_2(sc, FXP_CSR_FLOWCONTROL));
   }
   
   static void
   fxp_scb_cmd(struct fxp_softc *sc, int cmd)
   {
   
           if (cmd == FXP_SCB_COMMAND_CU_RESUME && sc->cu_resume_bug) {
                   CSR_WRITE_1(sc, FXP_CSR_SCB_COMMAND, FXP_CB_COMMAND_NOP);
                   fxp_scb_wait(sc);
           }
           CSR_WRITE_1(sc, FXP_CSR_SCB_COMMAND, cmd);
   }
   
   static void
   fxp_dma_wait(struct fxp_softc *sc, volatile uint16_t *status,
       bus_dma_tag_t dmat, bus_dmamap_t map)
   {
           int i = 10000;
   
           bus_dmamap_sync(dmat, map, BUS_DMASYNC_POSTREAD);
           while (!(le16toh(*status) & FXP_CB_STATUS_C) && --i) {
                   DELAY(2);
                   bus_dmamap_sync(dmat, map, BUS_DMASYNC_POSTREAD);
           }
           if (i == 0)
                   device_printf(sc->dev, "DMA timeout\n");
   }
   
   /*
    * Return identification string if this device is ours.
    */
   static int
   fxp_probe(device_t dev)
   {
           uint16_t devid;
           uint8_t revid;
           struct fxp_ident *ident;
   
           if (pci_get_vendor(dev) == FXP_VENDORID_INTEL) {
                   devid = pci_get_device(dev);
                   revid = pci_get_revid(dev);
                   for (ident = fxp_ident_table; ident->name != NULL; ident++) {
                           if (ident->devid == devid &&
                               (ident->revid == revid || ident->revid == -1)) {
                                   device_set_desc(dev, ident->name);
                                   return (BUS_PROBE_DEFAULT);
                           }
                   }
           }
           return (ENXIO);
   }
   
   static void
   fxp_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
   fxp_attach(device_t dev)
   {
           struct fxp_softc *sc;
           struct fxp_cb_tx *tcbp;
           struct fxp_tx *txp;
           struct fxp_rx *rxp;
           struct ifnet *ifp;
           uint32_t val;
           uint16_t data, myea[ETHER_ADDR_LEN / 2];
           int i, rid, m1, m2, prefer_iomap, maxtxseg;
           int error, s;
   
           error = 0;
           sc = device_get_softc(dev);
           sc->dev = dev;
           callout_init(&sc->stat_ch, CALLOUT_MPSAFE);
           mtx_init(&sc->sc_mtx, device_get_nameunit(dev), MTX_NETWORK_LOCK,
               MTX_DEF);
           ifmedia_init(&sc->sc_media, 0, fxp_serial_ifmedia_upd,
               fxp_serial_ifmedia_sts);
   
           s = splimp();
   
           /*
            * Enable bus mastering.
            */
           pci_enable_busmaster(dev);
           val = pci_read_config(dev, PCIR_COMMAND, 2);
   
           /*
            * Figure out which we should try first - memory mapping or i/o mapping?
            * We default to memory mapping. Then we accept an override from the
            * command line. Then we check to see which one is enabled.
            */
           m1 = PCIM_CMD_MEMEN;
           m2 = PCIM_CMD_PORTEN;
           prefer_iomap = 0;
           if (resource_int_value(device_get_name(dev), device_get_unit(dev),
               "prefer_iomap", &prefer_iomap) == 0 && prefer_iomap != 0) {
                   m1 = PCIM_CMD_PORTEN;
                   m2 = PCIM_CMD_MEMEN;
           }
   
           sc->rtp = (m1 == PCIM_CMD_MEMEN)? SYS_RES_MEMORY : SYS_RES_IOPORT;
           sc->rgd = (m1 == PCIM_CMD_MEMEN)? FXP_PCI_MMBA : FXP_PCI_IOBA;
           sc->mem = bus_alloc_resource_any(dev, sc->rtp, &sc->rgd, RF_ACTIVE);
           if (sc->mem == NULL) {
                   sc->rtp =
                       (m2 == PCIM_CMD_MEMEN)? SYS_RES_MEMORY : SYS_RES_IOPORT;
                   sc->rgd = (m2 == PCIM_CMD_MEMEN)? FXP_PCI_MMBA : FXP_PCI_IOBA;
                   sc->mem = bus_alloc_resource_any(dev, sc->rtp, &sc->rgd,
                                               RF_ACTIVE);
           }
   
           if (!sc->mem) {
                   error = ENXIO;
                   goto fail;
           }
           if (bootverbose) {
                   device_printf(dev, "using %s space register mapping\n",
                      sc->rtp == SYS_RES_MEMORY? "memory" : "I/O");
           }
   
           sc->sc_st = rman_get_bustag(sc->mem);
           sc->sc_sh = rman_get_bushandle(sc->mem);
   
           /*
            * Allocate our interrupt.
            */
           rid = 0;
           sc->irq = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
                                    RF_SHAREABLE | RF_ACTIVE);
           if (sc->irq == NULL) {
                   device_printf(dev, "could not map interrupt\n");
                   error = ENXIO;
                   goto fail;
           }
   
           /*
            * Reset to a stable state.
            */
           CSR_WRITE_4(sc, FXP_CSR_PORT, FXP_PORT_SELECTIVE_RESET);
           DELAY(10);
   
           /*
            * Find out how large of an SEEPROM we have.
            */
           fxp_autosize_eeprom(sc);
   
           /*
            * Find out the chip revision; lump all 82557 revs together.
            */
           fxp_read_eeprom(sc, &data, 5, 1);
           if ((data >> 8) == 1)
                   sc->revision = FXP_REV_82557;
           else
                   sc->revision = pci_get_revid(dev);
   
           /*
            * Determine whether we must use the 503 serial interface.
            */
           fxp_read_eeprom(sc, &data, 6, 1);
           if (sc->revision == FXP_REV_82557 && (data & FXP_PHY_DEVICE_MASK) != 0
               && (data & FXP_PHY_SERIAL_ONLY))
                   sc->flags |= FXP_FLAG_SERIAL_MEDIA;
   
           SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
               SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
               OID_AUTO, "int_delay", CTLTYPE_INT | CTLFLAG_RW,
               &sc->tunable_int_delay, 0, sysctl_hw_fxp_int_delay, "I",
               "FXP driver receive interrupt microcode bundling delay");
           SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
               SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
               OID_AUTO, "bundle_max", CTLTYPE_INT | CTLFLAG_RW,
               &sc->tunable_bundle_max, 0, sysctl_hw_fxp_bundle_max, "I",
               "FXP driver receive interrupt microcode bundle size limit");
           SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
               SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
               OID_AUTO, "rnr", CTLFLAG_RD, &sc->rnr, 0,
               "FXP RNR events");
           SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
               SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
               OID_AUTO, "noflow", CTLFLAG_RW, &sc->tunable_noflow, 0,
               "FXP flow control disabled");
   
           /*
            * Pull in device tunables.
            */
           sc->tunable_int_delay = TUNABLE_INT_DELAY;
           sc->tunable_bundle_max = TUNABLE_BUNDLE_MAX;
           sc->tunable_noflow = 1;
           (void) resource_int_value(device_get_name(dev), device_get_unit(dev),
               "int_delay", &sc->tunable_int_delay);
           (void) resource_int_value(device_get_name(dev), device_get_unit(dev),
               "bundle_max", &sc->tunable_bundle_max);
           (void) resource_int_value(device_get_name(dev), device_get_unit(dev),
               "noflow", &sc->tunable_noflow);
           sc->rnr = 0;
   
           /*
            * Enable workarounds for certain chip revision deficiencies.
            *
            * Systems based on the ICH2/ICH2-M chip from Intel, and possibly
            * some systems based a normal 82559 design, have a defect where
            * the chip can cause a PCI protocol violation if it receives
            * a CU_RESUME command when it is entering the IDLE state.  The 
            * workaround is to disable Dynamic Standby Mode, so the chip never
            * deasserts CLKRUN#, and always remains in an active state.
            *
            * See Intel 82801BA/82801BAM Specification Update, Errata #30.
            */
           i = pci_get_device(dev);
           if (i == 0x2449 || (i > 0x1030 && i < 0x1039) ||
               sc->revision >= FXP_REV_82559_A0) {
                   fxp_read_eeprom(sc, &data, 10, 1);
                   if (data & 0x02) {                      /* STB enable */
                           uint16_t cksum;
                           int i;
   
                           device_printf(dev,
                               "Disabling dynamic standby mode in EEPROM\n");
                           data &= ~0x02;
                           fxp_write_eeprom(sc, &data, 10, 1);
                           device_printf(dev, "New EEPROM ID: 0x%x\n", data);
                           cksum = 0;
                           for (i = 0; i < (1 << sc->eeprom_size) - 1; i++) {
                                   fxp_read_eeprom(sc, &data, i, 1);
                                   cksum += data;
                           }
                           i = (1 << sc->eeprom_size) - 1;
                           cksum = 0xBABA - cksum;
                           fxp_read_eeprom(sc, &data, i, 1);
                           fxp_write_eeprom(sc, &cksum, i, 1);
                           device_printf(dev,
                               "EEPROM checksum @ 0x%x: 0x%x -> 0x%x\n",
                               i, data, cksum);
   #if 1
                           /*
                            * If the user elects to continue, try the software
                            * workaround, as it is better than nothing.
                            */
                           sc->flags |= FXP_FLAG_CU_RESUME_BUG;
   #endif
                   }
           }
   
           /*
            * If we are not a 82557 chip, we can enable extended features.
            */
           if (sc->revision != FXP_REV_82557) {
                   /*
                    * If MWI is enabled in the PCI configuration, and there
                    * is a valid cacheline size (8 or 16 dwords), then tell
                    * the board to turn on MWI.
                    */
                   if (val & PCIM_CMD_MWRICEN &&
                       pci_read_config(dev, PCIR_CACHELNSZ, 1) != 0)
                           sc->flags |= FXP_FLAG_MWI_ENABLE;
   
                   /* turn on the extended TxCB feature */
                   sc->flags |= FXP_FLAG_EXT_TXCB;
   
                   /* enable reception of long frames for VLAN */
                   sc->flags |= FXP_FLAG_LONG_PKT_EN;
           } else {
                   /* a hack to get long VLAN frames on a 82557 */
                   sc->flags |= FXP_FLAG_SAVE_BAD;
           }
   
           /*
            * Enable use of extended RFDs and TCBs for 82550
            * and later chips. Note: we need extended TXCB support
            * too, but that's already enabled by the code above.
            * Be careful to do this only on the right devices.
            */
           if (sc->revision == FXP_REV_82550 || sc->revision == FXP_REV_82550_C ||
               sc->revision == FXP_REV_82551_E || sc->revision == FXP_REV_82551_F
               || sc->revision == FXP_REV_82551_10) {
                   sc->rfa_size = sizeof (struct fxp_rfa);
                   sc->tx_cmd = FXP_CB_COMMAND_IPCBXMIT;
                   sc->flags |= FXP_FLAG_EXT_RFA;
           } else {
                   sc->rfa_size = sizeof (struct fxp_rfa) - FXP_RFAX_LEN;
                   sc->tx_cmd = FXP_CB_COMMAND_XMIT;
           }
   
           /*
            * Allocate DMA tags and DMA safe memory.
            */
           maxtxseg = sc->flags & FXP_FLAG_EXT_RFA ? FXP_NTXSEG - 1 : FXP_NTXSEG;
           error = bus_dma_tag_create(NULL, 2, 0, BUS_SPACE_MAXADDR_32BIT,
               BUS_SPACE_MAXADDR, NULL, NULL, MCLBYTES * maxtxseg,
               maxtxseg, MCLBYTES, 0, busdma_lock_mutex, &Giant, &sc->fxp_mtag);
           if (error) {
                   device_printf(dev, "could not allocate dma tag\n");
                   goto fail;
           }
   
           error = bus_dma_tag_create(NULL, 4, 0, BUS_SPACE_MAXADDR_32BIT,
               BUS_SPACE_MAXADDR, NULL, NULL, sizeof(struct fxp_stats), 1,
               sizeof(struct fxp_stats), 0, busdma_lock_mutex, &Giant,
               &sc->fxp_stag);
           if (error) {
                   device_printf(dev, "could not allocate dma tag\n");
                   goto fail;
           }
   
           error = bus_dmamem_alloc(sc->fxp_stag, (void **)&sc->fxp_stats,
               BUS_DMA_NOWAIT | BUS_DMA_ZERO, &sc->fxp_smap);
           if (error)
                   goto fail;
           error = bus_dmamap_load(sc->fxp_stag, sc->fxp_smap, sc->fxp_stats,
               sizeof(struct fxp_stats), fxp_dma_map_addr, &sc->stats_addr, 0);
           if (error) {
                   device_printf(dev, "could not map the stats buffer\n");
                   goto fail;
           }
   
           error = bus_dma_tag_create(NULL, 4, 0, BUS_SPACE_MAXADDR_32BIT,
               BUS_SPACE_MAXADDR, NULL, NULL, FXP_TXCB_SZ, 1,
               FXP_TXCB_SZ, 0, busdma_lock_mutex, &Giant, &sc->cbl_tag);
           if (error) {
                   device_printf(dev, "could not allocate dma tag\n");
                   goto fail;
           }
   
           error = bus_dmamem_alloc(sc->cbl_tag, (void **)&sc->fxp_desc.cbl_list,
               BUS_DMA_NOWAIT | BUS_DMA_ZERO, &sc->cbl_map);
           if (error)
                   goto fail;
   
           error = bus_dmamap_load(sc->cbl_tag, sc->cbl_map,
               sc->fxp_desc.cbl_list, FXP_TXCB_SZ, fxp_dma_map_addr,
               &sc->fxp_desc.cbl_addr, 0);
           if (error) {
                   device_printf(dev, "could not map DMA memory\n");
                   goto fail;
           }
   
           error = bus_dma_tag_create(NULL, 4, 0, BUS_SPACE_MAXADDR_32BIT,
               BUS_SPACE_MAXADDR, NULL, NULL, sizeof(struct fxp_cb_mcs), 1,
               sizeof(struct fxp_cb_mcs), 0, busdma_lock_mutex, &Giant,
               &sc->mcs_tag);
           if (error) {
                   device_printf(dev, "could not allocate dma tag\n");
                   goto fail;
           }
   
           error = bus_dmamem_alloc(sc->mcs_tag, (void **)&sc->mcsp,
               BUS_DMA_NOWAIT, &sc->mcs_map);
           if (error)
                   goto fail;
           error = bus_dmamap_load(sc->mcs_tag, sc->mcs_map, sc->mcsp,
               sizeof(struct fxp_cb_mcs), fxp_dma_map_addr, &sc->mcs_addr, 0);
           if (error) {
                   device_printf(dev, "can't map the multicast setup command\n");
                   goto fail;
           }
   
           /*
            * Pre-allocate the TX DMA maps and setup the pointers to
            * the TX command blocks.
            */
           txp = sc->fxp_desc.tx_list;
           tcbp = sc->fxp_desc.cbl_list;
           for (i = 0; i < FXP_NTXCB; i++) {
                   txp[i].tx_cb = tcbp + i;
                   error = bus_dmamap_create(sc->fxp_mtag, 0, &txp[i].tx_map);
                   if (error) {
                           device_printf(dev, "can't create DMA map for TX\n");
                           goto fail;
                   }
           }
           error = bus_dmamap_create(sc->fxp_mtag, 0, &sc->spare_map);
           if (error) {
                   device_printf(dev, "can't create spare DMA map\n");
                   goto fail;
           }
   
           /*
            * Pre-allocate our receive buffers.
            */
           sc->fxp_desc.rx_head = sc->fxp_desc.rx_tail = NULL;
           for (i = 0; i < FXP_NRFABUFS; i++) {
                   rxp = &sc->fxp_desc.rx_list[i];
                   error = bus_dmamap_create(sc->fxp_mtag, 0, &rxp->rx_map);
                   if (error) {
                           device_printf(dev, "can't create DMA map for RX\n");
                           goto fail;
                   }
                   if (fxp_add_rfabuf(sc, rxp) != 0) {
                           error = ENOMEM;
                           goto fail;
                   }
           }
   
           /*
            * Read MAC address.
            */
           fxp_read_eeprom(sc, myea, 0, 3);
           sc->arpcom.ac_enaddr[0] = myea[0] & 0xff;
           sc->arpcom.ac_enaddr[1] = myea[0] >> 8;
           sc->arpcom.ac_enaddr[2] = myea[1] & 0xff;
           sc->arpcom.ac_enaddr[3] = myea[1] >> 8;
           sc->arpcom.ac_enaddr[4] = myea[2] & 0xff;
           sc->arpcom.ac_enaddr[5] = myea[2] >> 8;
           if (bootverbose) {
                   device_printf(dev, "PCI IDs: %04x %04x %04x %04x %04x\n",
                       pci_get_vendor(dev), pci_get_device(dev),
                       pci_get_subvendor(dev), pci_get_subdevice(dev),
                       pci_get_revid(dev));
                   fxp_read_eeprom(sc, &data, 10, 1);
                   device_printf(dev, "Dynamic Standby mode is %s\n",
                       data & 0x02 ? "enabled" : "disabled");
           }
   
           /*
            * If this is only a 10Mbps device, then there is no MII, and
            * the PHY will use a serial interface instead.
            *
            * The Seeq 80c24 AutoDUPLEX(tm) Ethernet Interface Adapter
            * doesn't have a programming interface of any sort.  The
            * media is sensed automatically based on how the link partner
            * is configured.  This is, in essence, manual configuration.
            */
           if (sc->flags & FXP_FLAG_SERIAL_MEDIA) {
                   ifmedia_add(&sc->sc_media, IFM_ETHER|IFM_MANUAL, 0, NULL);
                   ifmedia_set(&sc->sc_media, IFM_ETHER|IFM_MANUAL);
           } else {
                   if (mii_phy_probe(dev, &sc->miibus, fxp_ifmedia_upd,
                       fxp_ifmedia_sts)) {
                           device_printf(dev, "MII without any PHY!\n");
                           error = ENXIO;
                           goto fail;
                   }
           }
   
           ifp = &sc->arpcom.ac_if;
           if_initname(ifp, device_get_name(dev), device_get_unit(dev));
           ifp->if_baudrate = 100000000;
           ifp->if_init = fxp_init;
           ifp->if_softc = sc;
           ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
           ifp->if_ioctl = fxp_ioctl;
           ifp->if_start = fxp_start;
           ifp->if_watchdog = fxp_watchdog;
   
           ifp->if_capabilities = ifp->if_capenable = 0;
   
           /* Enable checksum offload for 82550 or better chips */
           if (sc->flags & FXP_FLAG_EXT_RFA) {
                   ifp->if_hwassist = FXP_CSUM_FEATURES;
                   ifp->if_capabilities |= IFCAP_HWCSUM;
                   ifp->if_capenable |= IFCAP_HWCSUM;
           }
   
   #ifdef DEVICE_POLLING
           /* Inform the world we support polling. */
           ifp->if_capabilities |= IFCAP_POLLING;
           ifp->if_capenable |= IFCAP_POLLING;
   #endif
   
           /*
            * Attach the interface.
            */
           ether_ifattach(ifp, sc->arpcom.ac_enaddr);
   
           /*
            * Tell the upper layer(s) we support long frames.
            * Must appear after the call to ether_ifattach() because
            * ether_ifattach() sets ifi_hdrlen to the default value.
            */
           ifp->if_data.ifi_hdrlen = sizeof(struct ether_vlan_header);
           ifp->if_capabilities |= IFCAP_VLAN_MTU;
           ifp->if_capenable |= IFCAP_VLAN_MTU; /* the hw bits already set */
   
           /*
            * Let the system queue as many packets as we have available
            * TX descriptors.
            */
           IFQ_SET_MAXLEN(&ifp->if_snd, FXP_NTXCB - 1);
           ifp->if_snd.ifq_drv_maxlen = FXP_NTXCB - 1;
           IFQ_SET_READY(&ifp->if_snd);
   
           /* 
            * Hook our interrupt after all initialization is complete.
            */
           error = bus_setup_intr(dev, sc->irq, INTR_TYPE_NET | INTR_MPSAFE,
                                  fxp_intr, sc, &sc->ih);
           if (error) {
                   device_printf(dev, "could not setup irq\n");
                   ether_ifdetach(&sc->arpcom.ac_if);
                   goto fail;
           }
   
   fail:
           splx(s);
           if (error)
                   fxp_release(sc);
           return (error);
   }
   
   /*
    * Release all resources.  The softc lock should not be held and the
    * interrupt should already be torn down.
    */
   static void
   fxp_release(struct fxp_softc *sc)
   {
           struct fxp_rx *rxp;
           struct fxp_tx *txp;
           int i;
   
           FXP_LOCK_ASSERT(sc, MA_NOTOWNED);
           KASSERT(sc->ih == NULL,
               ("fxp_release() called with intr handle still active"));
           if (sc->miibus)
                   device_delete_child(sc->dev, sc->miibus);
           bus_generic_detach(sc->dev);
           ifmedia_removeall(&sc->sc_media);
           if (sc->fxp_desc.cbl_list) {
                   bus_dmamap_unload(sc->cbl_tag, sc->cbl_map);
                   bus_dmamem_free(sc->cbl_tag, sc->fxp_desc.cbl_list,
                       sc->cbl_map);
           }
           if (sc->fxp_stats) {
                   bus_dmamap_unload(sc->fxp_stag, sc->fxp_smap);
                   bus_dmamem_free(sc->fxp_stag, sc->fxp_stats, sc->fxp_smap);
           }
           if (sc->mcsp) {
                   bus_dmamap_unload(sc->mcs_tag, sc->mcs_map);
                   bus_dmamem_free(sc->mcs_tag, sc->mcsp, sc->mcs_map);
           }
           if (sc->irq)
                   bus_release_resource(sc->dev, SYS_RES_IRQ, 0, sc->irq);
           if (sc->mem)
                   bus_release_resource(sc->dev, sc->rtp, sc->rgd, sc->mem);
           if (sc->fxp_mtag) {
                   for (i = 0; i < FXP_NRFABUFS; i++) {
                           rxp = &sc->fxp_desc.rx_list[i];
                           if (rxp->rx_mbuf != NULL) {
                                   bus_dmamap_sync(sc->fxp_mtag, rxp->rx_map,
                                       BUS_DMASYNC_POSTREAD);
                                   bus_dmamap_unload(sc->fxp_mtag, rxp->rx_map);
                                   m_freem(rxp->rx_mbuf);
                           }
                           bus_dmamap_destroy(sc->fxp_mtag, rxp->rx_map);
                   }
                   bus_dmamap_destroy(sc->fxp_mtag, sc->spare_map);
                   for (i = 0; i < FXP_NTXCB; i++) {
                           txp = &sc->fxp_desc.tx_list[i];
                           if (txp->tx_mbuf != NULL) {
                                   bus_dmamap_sync(sc->fxp_mtag, txp->tx_map,
                                       BUS_DMASYNC_POSTWRITE);
                                   bus_dmamap_unload(sc->fxp_mtag, txp->tx_map);
                                   m_freem(txp->tx_mbuf);
                           }
                           bus_dmamap_destroy(sc->fxp_mtag, txp->tx_map);
                   }
                   bus_dma_tag_destroy(sc->fxp_mtag);
           }
           if (sc->fxp_stag)
                   bus_dma_tag_destroy(sc->fxp_stag);
           if (sc->cbl_tag)
                   bus_dma_tag_destroy(sc->cbl_tag);
           if (sc->mcs_tag)
                   bus_dma_tag_destroy(sc->mcs_tag);
   
           mtx_destroy(&sc->sc_mtx);
   }
   
   /*
    * Detach interface.
    */
   static int
   fxp_detach(device_t dev)
   {
           struct fxp_softc *sc = device_get_softc(dev);
           int s;
   
           FXP_LOCK(sc);
           s = splimp();
   
           sc->suspended = 1;      /* Do same thing as we do for suspend */
           /*
            * Close down routes etc.
            */
           ether_ifdetach(&sc->arpcom.ac_if);
   
           /*
            * Stop DMA and drop transmit queue, but disable interrupts first.
            */
           CSR_WRITE_1(sc, FXP_CSR_SCB_INTRCNTL, FXP_SCB_INTR_DISABLE);
           fxp_stop(sc);
           FXP_UNLOCK(sc);
   
           /*
            * Unhook interrupt before dropping lock. This is to prevent
            * races with fxp_intr().
            */
           bus_teardown_intr(sc->dev, sc->irq, sc->ih);
           sc->ih = NULL;
   
           splx(s);
   
           /* Release our allocated resources. */
           fxp_release(sc);
           return (0);
   }
   
   /*
    * Device shutdown routine. Called at system shutdown after sync. The
    * main purpose of this routine is to shut off receiver DMA so that
    * kernel memory doesn't get clobbered during warmboot.
    */
   static int
   fxp_shutdown(device_t dev)
   {
           /*
            * Make sure that DMA is disabled prior to reboot. Not doing
            * do could allow DMA to corrupt kernel memory during the
            * reboot before the driver initializes.
            */
           fxp_stop((struct fxp_softc *) device_get_softc(dev));
           return (0);
   }
   
   /*
    * Device suspend routine.  Stop the interface and save some PCI
    * settings in case the BIOS doesn't restore them properly on
    * resume.
    */
   static int
   fxp_suspend(device_t dev)
   {
           struct fxp_softc *sc = device_get_softc(dev);
           int i, s;
   
           FXP_LOCK(sc);
           s = splimp();
   
           fxp_stop(sc);
           
           for (i = 0; i < 5; i++)
                   sc->saved_maps[i] = pci_read_config(dev, PCIR_BAR(i), 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);
   
           sc->suspended = 1;
   
           FXP_UNLOCK(sc);
           splx(s);
           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
   fxp_resume(device_t dev)
   {
           struct fxp_softc *sc = device_get_softc(dev);
           struct ifnet *ifp = &sc->sc_if;
           uint16_t pci_command;
           int i, s;
   
           FXP_LOCK(sc);
           s = splimp();
   
           /* better way to do this? */
           for (i = 0; i < 5; i++)
                   pci_write_config(dev, PCIR_BAR(i), 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_command = pci_read_config(dev, PCIR_COMMAND, 2);
           pci_command |= (PCIM_CMD_MEMEN|PCIM_CMD_BUSMASTEREN);
           pci_write_config(dev, PCIR_COMMAND, pci_command, 2);
   
           CSR_WRITE_4(sc, FXP_CSR_PORT, FXP_PORT_SELECTIVE_RESET);
           DELAY(10);
   
           /* reinitialize interface if necessary */
           if (ifp->if_flags & IFF_UP)
                   fxp_init_body(sc);
  
          sc->suspended = 0;
  
          FXP_UNLOCK(sc);
          splx(s);
          return (0);
  }
  
  static void 
  fxp_eeprom_shiftin(struct fxp_softc *sc, int data, int length)
  {
          uint16_t reg;
          int x;
  
          /*
           * Shift in data.
           */
          for (x = 1 << (length - 1); x; x >>= 1) {
                  if (data & x)
                          reg = FXP_EEPROM_EECS | FXP_EEPROM_EEDI;
                  else
                          reg = FXP_EEPROM_EECS;
                  CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, reg);
                  DELAY(1);
                  CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, reg | FXP_EEPROM_EESK);
                  DELAY(1);
                  CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, reg);
                  DELAY(1);
          }
  }
  
  /*
   * Read from the serial EEPROM. Basically, you manually shift in
   * the read opcode (one bit at a time) and then shift in the address,
   * and then you shift out the data (all of this one bit at a time).
   * The word size is 16 bits, so you have to provide the address for
   * every 16 bits of data.
   */
  static uint16_t
  fxp_eeprom_getword(struct fxp_softc *sc, int offset, int autosize)
  {
          uint16_t reg, data;
          int x;
  
          CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, FXP_EEPROM_EECS);
          /*
           * Shift in read opcode.
           */
          fxp_eeprom_shiftin(sc, FXP_EEPROM_OPC_READ, 3);
          /*
           * Shift in address.
           */
          data = 0;
          for (x = 1 << (sc->eeprom_size - 1); x; x >>= 1) {
                  if (offset & x)
                          reg = FXP_EEPROM_EECS | FXP_EEPROM_EEDI;
                  else
                          reg = FXP_EEPROM_EECS;
                  CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, reg);
                  DELAY(1);
                  CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, reg | FXP_EEPROM_EESK);
                  DELAY(1);
                  CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, reg);
                  DELAY(1);
                  reg = CSR_READ_2(sc, FXP_CSR_EEPROMCONTROL) & FXP_EEPROM_EEDO;
                  data++;
                  if (autosize && reg == 0) {
                          sc->eeprom_size = data;
                          break;
                  }
          }
          /*
           * Shift out data.
           */
          data = 0;
          reg = FXP_EEPROM_EECS;
          for (x = 1 << 15; x; x >>= 1) {
                  CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, reg | FXP_EEPROM_EESK);
                  DELAY(1);
                  if (CSR_READ_2(sc, FXP_CSR_EEPROMCONTROL) & FXP_EEPROM_EEDO)
                          data |= x;
                  CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, reg);
                  DELAY(1);
          }
          CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, 0);
          DELAY(1);
  
          return (data);
  }
  
  static void
  fxp_eeprom_putword(struct fxp_softc *sc, int offset, uint16_t data)
  {
          int i;
  
          /*
           * Erase/write enable.
           */
          CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, FXP_EEPROM_EECS);
          fxp_eeprom_shiftin(sc, 0x4, 3);
          fxp_eeprom_shiftin(sc, 0x03 << (sc->eeprom_size - 2), sc->eeprom_size);
          CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, 0);
          DELAY(1);
          /*
           * Shift in write opcode, address, data.
           */
          CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, FXP_EEPROM_EECS);
          fxp_eeprom_shiftin(sc, FXP_EEPROM_OPC_WRITE, 3);
          fxp_eeprom_shiftin(sc, offset, sc->eeprom_size);
          fxp_eeprom_shiftin(sc, data, 16);
          CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, 0);
          DELAY(1);
          /*
           * Wait for EEPROM to finish up.
           */
          CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, FXP_EEPROM_EECS);
          DELAY(1);
          for (i = 0; i < 1000; i++) {
                  if (CSR_READ_2(sc, FXP_CSR_EEPROMCONTROL) & FXP_EEPROM_EEDO)
                          break;
                  DELAY(50);
          }
          CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, 0);
          DELAY(1);
          /*
           * Erase/write disable.
           */
          CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, FXP_EEPROM_EECS);
          fxp_eeprom_shiftin(sc, 0x4, 3);
          fxp_eeprom_shiftin(sc, 0, sc->eeprom_size);
          CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, 0);
          DELAY(1);
  }
  
  /*
   * From NetBSD:
   *
   * Figure out EEPROM size.
   *
   * 559's can have either 64-word or 256-word EEPROMs, the 558
   * datasheet only talks about 64-word EEPROMs, and the 557 datasheet
   * talks about the existance of 16 to 256 word EEPROMs.
   *
   * The only known sizes are 64 and 256, where the 256 version is used
   * by CardBus cards to store CIS information.
   *
   * The address is shifted in msb-to-lsb, and after the last
   * address-bit the EEPROM is supposed to output a `dummy zero' bit,
   * after which follows the actual data. We try to detect this zero, by
   * probing the data-out bit in the EEPROM control register just after
   * having shifted in a bit. If the bit is zero, we assume we've
   * shifted enough address bits. The data-out should be tri-state,
   * before this, which should translate to a logical one.
   */
  static void
  fxp_autosize_eeprom(struct fxp_softc *sc)
  {
  
          /* guess maximum size of 256 words */
          sc->eeprom_size = 8;
  
          /* autosize */
          (void) fxp_eeprom_getword(sc, 0, 1);
  }
  
  static void
  fxp_read_eeprom(struct fxp_softc *sc, u_short *data, int offset, int words)
  {
          int i;
  
          for (i = 0; i < words; i++)
                  data[i] = fxp_eeprom_getword(sc, offset + i, 0);
  }
  
  static void
  fxp_write_eeprom(struct fxp_softc *sc, u_short *data, int offset, int words)
  {
          int i;
  
          for (i = 0; i < words; i++)
                  fxp_eeprom_putword(sc, offset + i, data[i]);
  }
  
  static void
  fxp_dma_map_txbuf(void *arg, bus_dma_segment_t *segs, int nseg,
      bus_size_t mapsize, int error)
  {
          struct fxp_softc *sc;
          struct fxp_cb_tx *txp;
          int i;
  
          if (error)
                  return;
  
          KASSERT(nseg <= FXP_NTXSEG, ("too many DMA segments"));
  
          sc = arg;
          txp = sc->fxp_desc.tx_last->tx_next->tx_cb;
          for (i = 0; i < nseg; i++) {
                  KASSERT(segs[i].ds_len <= MCLBYTES, ("segment size too large"));
                  /*
                   * If this is an 82550/82551, then we're using extended
                   * TxCBs _and_ we're using checksum offload. This means
                   * that the TxCB is really an IPCB. One major difference
                   * between the two is that with plain extended TxCBs,
                   * the bottom half of the TxCB contains two entries from
                   * the TBD array, whereas IPCBs contain just one entry:
                   * one entry (8 bytes) has been sacrificed for the TCP/IP
                   * checksum offload control bits. So to make things work
                   * right, we have to start filling in the TBD array
                   * starting from a different place depending on whether
                   * the chip is an 82550/82551 or not.
                   */
                  if (sc->flags & FXP_FLAG_EXT_RFA) {
                          txp->tbd[i + 1].tb_addr = htole32(segs[i].ds_addr);
                          txp->tbd[i + 1].tb_size = htole32(segs[i].ds_len);
                  } else {
                          txp->tbd[i].tb_addr = htole32(segs[i].ds_addr);
                          txp->tbd[i].tb_size = htole32(segs[i].ds_len);
                  }
          }
          txp->tbd_number = nseg;
  }
  
  /*
   * Grab the softc lock and call the real fxp_start_body() routine
   */
  static void
  fxp_start(struct ifnet *ifp)
  {
          struct fxp_softc *sc = ifp->if_softc;
  
          FXP_LOCK(sc);
          fxp_start_body(ifp);
          FXP_UNLOCK(sc);
  }
  
  /*
   * Start packet transmission on the interface.  
   * This routine must be called with the softc lock held, and is an
   * internal entry point only.
   */
  static void
  fxp_start_body(struct ifnet *ifp)
  {
          struct fxp_softc *sc = ifp->if_softc;
          struct fxp_tx *txp;
          struct mbuf *mb_head;
          int error;
  
          FXP_LOCK_ASSERT(sc, MA_OWNED);
          /*
           * See if we need to suspend xmit until the multicast filter
           * has been reprogrammed (which can only be done at the head
           * of the command chain).
           */
          if (sc->need_mcsetup) {
                  return;
          }
  
          txp = NULL;
  
          /*
           * We're finished if there is nothing more to add to the list or if
           * we're all filled up with buffers to transmit.
           * NOTE: One TxCB is reserved to guarantee that fxp_mc_setup() can add
           *       a NOP command when needed.
           */
          while (!IFQ_DRV_IS_EMPTY(&ifp->if_snd) &&
              sc->tx_queued < FXP_NTXCB - 1) {
  
                  /*
                   * Grab a packet to transmit.
                   */
                  IFQ_DRV_DEQUEUE(&ifp->if_snd, mb_head);
                  if (mb_head == NULL)
                          break;
  
                  /*
                   * Get pointer to next available tx desc.
                   */
                  txp = sc->fxp_desc.tx_last->tx_next;
  
                  /*
                   * A note in Appendix B of the Intel 8255x 10/100 Mbps
                   * Ethernet Controller Family Open Source Software
                   * Developer Manual says:
                   *   Using software parsing is only allowed with legal
                   *   TCP/IP or UDP/IP packets.
                   *   ...
                   *   For all other datagrams, hardware parsing must
                   *   be used.
                   * Software parsing appears to truncate ICMP and
                   * fragmented UDP packets that contain one to three
                   * bytes in the second (and final) mbuf of the packet.
                   */
                  if (sc->flags & FXP_FLAG_EXT_RFA)
                          txp->tx_cb->ipcb_ip_activation_high =
                              FXP_IPCB_HARDWAREPARSING_ENABLE;
  
                  /*
                   * Deal with TCP/IP checksum offload. Note that
                   * in order for TCP checksum offload to work,
                   * the pseudo header checksum must have already
                   * been computed and stored in the checksum field
                   * in the TCP header. The stack should have
                   * already done this for us.
                   */
  
                  if (mb_head->m_pkthdr.csum_flags) {
                          if (mb_head->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
                                  txp->tx_cb->ipcb_ip_schedule =
                                      FXP_IPCB_TCPUDP_CHECKSUM_ENABLE;
                                  if (mb_head->m_pkthdr.csum_flags & CSUM_TCP)
                                          txp->tx_cb->ipcb_ip_schedule |=
                                              FXP_IPCB_TCP_PACKET;
                          }
  #ifdef FXP_IP_CSUM_WAR
                  /*
                   * XXX The 82550 chip appears to have trouble
                   * dealing with IP header checksums in very small
                   * datagrams, namely fragments from 1 to 3 bytes
                   * in size. For example, say you want to transmit
                   * a UDP packet of 1473 bytes. The packet will be
                   * fragmented over two IP datagrams, the latter
                   * containing only one byte of data. The 82550 will
                   * botch the header checksum on the 1-byte fragment.
                   * As long as the datagram contains 4 or more bytes
                   * of data, you're ok.
                   *
                   * The following code attempts to work around this
                   * problem: if the datagram is less than 38 bytes
                   * in size (14 bytes ether header, 20 bytes IP header,
                   * plus 4 bytes of data), we punt and compute the IP
                   * header checksum by hand. This workaround doesn't
                   * work very well, however, since it can be fooled
                   * by things like VLAN tags and IP options that make
                   * the header sizes/offsets vary.
                   */
  
                          if (mb_head->m_pkthdr.csum_flags & CSUM_IP) {
                                  if (mb_head->m_pkthdr.len < 38) {
                                          struct ip *ip;
                                          mb_head->m_data += ETHER_HDR_LEN;
                                          ip = mtod(mb_head, struct ip *);
                                          ip->ip_sum = in_cksum(mb_head,
                                              ip->ip_hl << 2);
                                          mb_head->m_data -= ETHER_HDR_LEN;
                                  } else {
                                          txp->tx_cb->ipcb_ip_activation_high =
                                              FXP_IPCB_HARDWAREPARSING_ENABLE;
                                          txp->tx_cb->ipcb_ip_schedule |=
                                              FXP_IPCB_IP_CHECKSUM_ENABLE;
                                  }
                          }
  #endif
                  }
  
                  /*
                   * Go through each of the mbufs in the chain and initialize
                   * the transmit buffer descriptors with the physical address
                   * and size of the mbuf.
                   */
                  error = bus_dmamap_load_mbuf(sc->fxp_mtag, txp->tx_map,
                      mb_head, fxp_dma_map_txbuf, sc, 0);
  
                  if (error && error != EFBIG) {
                          device_printf(sc->dev, "can't map mbuf (error %d)\n",
                              error);
                          m_freem(mb_head);
                          break;
                  }
  
                  if (error) {
                          struct mbuf *mn;
  
                          /*
                           * We ran out of segments. We have to recopy this
                           * mbuf chain first. Bail out if we can't get the
                           * new buffers.
                           */
                          mn = m_defrag(mb_head, M_DONTWAIT);
                          if (mn == NULL) {
                                  m_freem(mb_head);
                                  break;
                          } else {
                                  mb_head = mn;
                          }
                          error = bus_dmamap_load_mbuf(sc->fxp_mtag, txp->tx_map,
                              mb_head, fxp_dma_map_txbuf, sc, 0);
                          if (error) {
                                  device_printf(sc->dev,
                                      "can't map mbuf (error %d)\n", error);
                                  m_freem(mb_head);
                                  break;
                          }
                  }
  
                  bus_dmamap_sync(sc->fxp_mtag, txp->tx_map,
                      BUS_DMASYNC_PREWRITE);
  
                  txp->tx_mbuf = mb_head;
                  txp->tx_cb->cb_status = 0;
                  txp->tx_cb->byte_count = 0;
                  if (sc->tx_queued != FXP_CXINT_THRESH - 1) {
                          txp->tx_cb->cb_command =
                              htole16(sc->tx_cmd | FXP_CB_COMMAND_SF |
                              FXP_CB_COMMAND_S);
                  } else {
                          txp->tx_cb->cb_command =
                              htole16(sc->tx_cmd | FXP_CB_COMMAND_SF |
                              FXP_CB_COMMAND_S | FXP_CB_COMMAND_I);
                          /*
                           * Set a 5 second timer just in case we don't hear
                           * from the card again.
                           */
                          ifp->if_timer = 5;
                  }
                  txp->tx_cb->tx_threshold = tx_threshold;
  
                  /*
                   * Advance the end of list forward.
                   */
  
  #ifdef __alpha__
                  /*
                   * On platforms which can't access memory in 16-bit
                   * granularities, we must prevent the card from DMA'ing
                   * up the status while we update the command field.
                   * This could cause us to overwrite the completion status.
                   * XXX This is probably bogus and we're _not_ looking
                   * for atomicity here.
                   */
                  atomic_clear_16(&sc->fxp_desc.tx_last->tx_cb->cb_command,
                      htole16(FXP_CB_COMMAND_S));
  #else
                  sc->fxp_desc.tx_last->tx_cb->cb_command &=
                      htole16(~FXP_CB_COMMAND_S);
  #endif /*__alpha__*/
                  sc->fxp_desc.tx_last = txp;
  
                  /*
                   * Advance the beginning of the list forward if there are
                   * no other packets queued (when nothing is queued, tx_first
                   * sits on the last TxCB that was sent out).
                   */
                  if (sc->tx_queued == 0)
                          sc->fxp_desc.tx_first = txp;
  
                  sc->tx_queued++;
  
                  /*
                   * Pass packet to bpf if there is a listener.
                   */
                  BPF_MTAP(ifp, mb_head);
          }
          bus_dmamap_sync(sc->cbl_tag, sc->cbl_map, BUS_DMASYNC_PREWRITE);
  
          /*
           * We're finished. If we added to the list, issue a RESUME to get DMA
           * going again if suspended.
           */
          if (txp != NULL) {
                  fxp_scb_wait(sc);
                  fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_RESUME);
          }
  }
  
  #ifdef DEVICE_POLLING
  static poll_handler_t fxp_poll;
  
  static void
  fxp_poll(struct ifnet *ifp, enum poll_cmd cmd, int count)
  {
          struct fxp_softc *sc = ifp->if_softc;
          uint8_t statack;
  
          FXP_LOCK(sc);
          if (!(ifp->if_capenable & IFCAP_POLLING)) {
                  ether_poll_deregister(ifp);
                  cmd = POLL_DEREGISTER;
          }
          if (cmd == POLL_DEREGISTER) {   /* final call, enable interrupts */
                  CSR_WRITE_1(sc, FXP_CSR_SCB_INTRCNTL, 0);
                  FXP_UNLOCK(sc);
                  return;
          }
          statack = FXP_SCB_STATACK_CXTNO | FXP_SCB_STATACK_CNA |
              FXP_SCB_STATACK_FR;
          if (cmd == POLL_AND_CHECK_STATUS) {
                  uint8_t tmp;
  
                  tmp = CSR_READ_1(sc, FXP_CSR_SCB_STATACK);
                  if (tmp == 0xff || tmp == 0) {
                          FXP_UNLOCK(sc);
                          return; /* nothing to do */
                  }
                  tmp &= ~statack;
                  /* ack what we can */
                  if (tmp != 0)
                          CSR_WRITE_1(sc, FXP_CSR_SCB_STATACK, tmp);
                  statack |= tmp;
          }
          fxp_intr_body(sc, ifp, statack, count);
          FXP_UNLOCK(sc);
  }
  #endif /* DEVICE_POLLING */
  
  /*
   * Process interface interrupts.
   */
  static void
  fxp_intr(void *xsc)
  {
          struct fxp_softc *sc = xsc;
          struct ifnet *ifp = &sc->sc_if;
          uint8_t statack;
  
          FXP_LOCK(sc);
          if (sc->suspended) {
                  FXP_UNLOCK(sc);
                  return;
          }
  
  #ifdef DEVICE_POLLING
          if (ifp->if_flags & IFF_POLLING) {
                  FXP_UNLOCK(sc);
                  return;
          }
          if ((ifp->if_capenable & IFCAP_POLLING) &&
              ether_poll_register(fxp_poll, ifp)) {
                  /* disable interrupts */
                  CSR_WRITE_1(sc, FXP_CSR_SCB_INTRCNTL, FXP_SCB_INTR_DISABLE);
                  FXP_UNLOCK(sc);
                  fxp_poll(ifp, 0, 1);
                  return;
          }
  #endif
          while ((statack = CSR_READ_1(sc, FXP_CSR_SCB_STATACK)) != 0) {
                  /*
                   * It should not be possible to have all bits set; the
                   * FXP_SCB_INTR_SWI bit always returns 0 on a read.  If 
                   * all bits are set, this may indicate that the card has
                   * been physically ejected, so ignore it.
                   */  
                  if (statack == 0xff) {
                          FXP_UNLOCK(sc);
                          return;
                  }
  
                  /*
                   * First ACK all the interrupts in this pass.
                   */
                  CSR_WRITE_1(sc, FXP_CSR_SCB_STATACK, statack);
                  fxp_intr_body(sc, ifp, statack, -1);
          }
          FXP_UNLOCK(sc);
  }
  
  static void
  fxp_txeof(struct fxp_softc *sc)
  {
          struct fxp_tx *txp;
  
          bus_dmamap_sync(sc->cbl_tag, sc->cbl_map, BUS_DMASYNC_PREREAD);
          for (txp = sc->fxp_desc.tx_first; sc->tx_queued &&
              (le16toh(txp->tx_cb->cb_status) & FXP_CB_STATUS_C) != 0;
              txp = txp->tx_next) {
                  if (txp->tx_mbuf != NULL) {
                          bus_dmamap_sync(sc->fxp_mtag, txp->tx_map,
                              BUS_DMASYNC_POSTWRITE);
                          bus_dmamap_unload(sc->fxp_mtag, txp->tx_map);
                          m_freem(txp->tx_mbuf);
                          txp->tx_mbuf = NULL;
                          /* clear this to reset csum offload bits */
                          txp->tx_cb->tbd[0].tb_addr = 0;
                  }
                  sc->tx_queued--;
          }
          sc->fxp_desc.tx_first = txp;
          bus_dmamap_sync(sc->cbl_tag, sc->cbl_map, BUS_DMASYNC_PREWRITE);
  }
  
  static void
  fxp_intr_body(struct fxp_softc *sc, struct ifnet *ifp, uint8_t statack,
      int count)
  {
          struct mbuf *m;
          struct fxp_rx *rxp;
          struct fxp_rfa *rfa;
          int rnr = (statack & FXP_SCB_STATACK_RNR) ? 1 : 0;
          int fxp_rc = 0;
  
          FXP_LOCK_ASSERT(sc, MA_OWNED);
          if (rnr)
                  sc->rnr++;
  #ifdef DEVICE_POLLING
          /* Pick up a deferred RNR condition if `count' ran out last time. */
          if (sc->flags & FXP_FLAG_DEFERRED_RNR) {
                  sc->flags &= ~FXP_FLAG_DEFERRED_RNR;
                  rnr = 1;
          }
  #endif
  
          /*
           * Free any finished transmit mbuf chains.
           *
           * Handle the CNA event likt a CXTNO event. It used to
           * be that this event (control unit not ready) was not
           * encountered, but it is now with the SMPng modifications.
           * The exact sequence of events that occur when the interface
           * is brought up are different now, and if this event
           * goes unhandled, the configuration/rxfilter setup sequence
           * can stall for several seconds. The result is that no
           * packets go out onto the wire for about 5 to 10 seconds
           * after the interface is ifconfig'ed for the first time.
           */
          if (statack & (FXP_SCB_STATACK_CXTNO | FXP_SCB_STATACK_CNA)) {
                  fxp_txeof(sc);
  
                  ifp->if_timer = 0;
                  if (sc->tx_queued == 0) {
                          if (sc->need_mcsetup)
                                  fxp_mc_setup(sc);
                  }
                  /*
                   * Try to start more packets transmitting.
                   */
                  if (!IFQ_DRV_IS_EMPTY(&ifp->if_snd))
                          fxp_start_body(ifp);
          }
  
          /*
           * Just return if nothing happened on the receive side.
           */
          if (!rnr && (statack & FXP_SCB_STATACK_FR) == 0)
                  return;
  
          /*
           * Process receiver interrupts. If a no-resource (RNR)
           * condition exists, get whatever packets we can and
           * re-start the receiver.
           *
           * When using polling, we do not process the list to completion,
           * so when we get an RNR interrupt we must defer the restart
           * until we hit the last buffer with the C bit set.
           * If we run out of cycles and rfa_headm has the C bit set,
           * record the pending RNR in the FXP_FLAG_DEFERRED_RNR flag so
           * that the info will be used in the subsequent polling cycle.
           */
          for (;;) {
                  rxp = sc->fxp_desc.rx_head;
                  m = rxp->rx_mbuf;
                  rfa = (struct fxp_rfa *)(m->m_ext.ext_buf +
                      RFA_ALIGNMENT_FUDGE);
                  bus_dmamap_sync(sc->fxp_mtag, rxp->rx_map,
                      BUS_DMASYNC_POSTREAD);
  
  #ifdef DEVICE_POLLING /* loop at most count times if count >=0 */
                  if (count >= 0 && count-- == 0) {
                          if (rnr) {
                                  /* Defer RNR processing until the next time. */
                                  sc->flags |= FXP_FLAG_DEFERRED_RNR;
                                  rnr = 0;
                          }
                          break;
                  }
  #endif /* DEVICE_POLLING */
  
                  if ((le16toh(rfa->rfa_status) & FXP_RFA_STATUS_C) == 0)
                          break;
  
                  /*
                   * Advance head forward.
                   */
                  sc->fxp_desc.rx_head = rxp->rx_next;
  
                  /*
                   * Add a new buffer to the receive chain.
                   * If this fails, the old buffer is recycled
                   * instead.
                   */
                  fxp_rc = fxp_add_rfabuf(sc, rxp);
                  if (fxp_rc == 0) {
                          int total_len;
  
                          /*
                           * Fetch packet length (the top 2 bits of
                           * actual_size are flags set by the controller
                           * upon completion), and drop the packet in case
                           * of bogus length or CRC errors.
                           */
                          total_len = le16toh(rfa->actual_size) & 0x3fff;
                          if (total_len < sizeof(struct ether_header) ||
                              total_len > MCLBYTES - RFA_ALIGNMENT_FUDGE -
                                  sc->rfa_size ||
                              le16toh(rfa->rfa_status) & FXP_RFA_STATUS_CRC) {
                                  m_freem(m);
                                  continue;
                          }
  
                          /* Do IP checksum checking. */
                          if (le16toh(rfa->rfa_status) & FXP_RFA_STATUS_PARSE) {
                                  if (rfa->rfax_csum_sts &
                                      FXP_RFDX_CS_IP_CSUM_BIT_VALID)
                                          m->m_pkthdr.csum_flags |=
                                              CSUM_IP_CHECKED;
                                  if (rfa->rfax_csum_sts &
                                      FXP_RFDX_CS_IP_CSUM_VALID)
                                          m->m_pkthdr.csum_flags |=
                                              CSUM_IP_VALID;
                                  if ((rfa->rfax_csum_sts &
                                      FXP_RFDX_CS_TCPUDP_CSUM_BIT_VALID) &&
                                      (rfa->rfax_csum_sts &
                                      FXP_RFDX_CS_TCPUDP_CSUM_VALID)) {
                                          m->m_pkthdr.csum_flags |=
                                              CSUM_DATA_VALID|CSUM_PSEUDO_HDR;
                                          m->m_pkthdr.csum_data = 0xffff;
                                  }
                          }
  
                          m->m_pkthdr.len = m->m_len = total_len;
                          m->m_pkthdr.rcvif = ifp;
  
                          /*
                           * Drop locks before calling if_input() since it
                           * may re-enter fxp_start() in the netisr case.
                           * This would result in a lock reversal.  Better
                           * performance might be obtained by chaining all
                           * packets received, dropping the lock, and then
                           * calling if_input() on each one.
                           */
                          FXP_UNLOCK(sc);
                          (*ifp->if_input)(ifp, m);
                          FXP_LOCK(sc);
                  } else if (fxp_rc == ENOBUFS) {
                          rnr = 0;
                          break;
                  }
          }
          if (rnr) {
                  fxp_scb_wait(sc);
                  CSR_WRITE_4(sc, FXP_CSR_SCB_GENERAL,
                      sc->fxp_desc.rx_head->rx_addr);
                  fxp_scb_cmd(sc, FXP_SCB_COMMAND_RU_START);
          }
  }
  
  /*
   * Update packet in/out/collision statistics. The i82557 doesn't
   * allow you to access these counters without doing a fairly
   * expensive DMA to get _all_ of the statistics it maintains, so
   * we do this operation here only once per second. The statistics
   * counters in the kernel are updated from the previous dump-stats
   * DMA and then a new dump-stats DMA is started. The on-chip
   * counters are zeroed when the DMA completes. If we can't start
   * the DMA immediately, we don't wait - we just prepare to read
   * them again next time.
   */
  static void
  fxp_tick(void *xsc)
  {
          struct fxp_softc *sc = xsc;
          struct ifnet *ifp = &sc->sc_if;
          struct fxp_stats *sp = sc->fxp_stats;
          int s;
  
          FXP_LOCK(sc);
          s = splimp();
          bus_dmamap_sync(sc->fxp_stag, sc->fxp_smap, BUS_DMASYNC_POSTREAD);
          ifp->if_opackets += le32toh(sp->tx_good);
          ifp->if_collisions += le32toh(sp->tx_total_collisions);
          if (sp->rx_good) {
                  ifp->if_ipackets += le32toh(sp->rx_good);
                  sc->rx_idle_secs = 0;
          } else {
                  /*
                   * Receiver's been idle for another second.
                   */
                  sc->rx_idle_secs++;
          }
          ifp->if_ierrors +=
              le32toh(sp->rx_crc_errors) +
              le32toh(sp->rx_alignment_errors) +
              le32toh(sp->rx_rnr_errors) +
              le32toh(sp->rx_overrun_errors);
          /*
           * If any transmit underruns occured, bump up the transmit
           * threshold by another 512 bytes (64 * 8).
           */
          if (sp->tx_underruns) {
                  ifp->if_oerrors += le32toh(sp->tx_underruns);
                  if (tx_threshold < 192)
                          tx_threshold += 64;
          }
  
          /*
           * Release any xmit buffers that have completed DMA. This isn't
           * strictly necessary to do here, but it's advantagous for mbufs
           * with external storage to be released in a timely manner rather
           * than being defered for a potentially long time. This limits
           * the delay to a maximum of one second.
           */ 
          fxp_txeof(sc);
  
          /*
           * If we haven't received any packets in FXP_MAC_RX_IDLE seconds,
           * then assume the receiver has locked up and attempt to clear
           * the condition by reprogramming the multicast filter. This is
           * a work-around for a bug in the 82557 where the receiver locks
           * up if it gets certain types of garbage in the syncronization
           * bits prior to the packet header. This bug is supposed to only
           * occur in 10Mbps mode, but has been seen to occur in 100Mbps
           * mode as well (perhaps due to a 10/100 speed transition).
           */
          if (sc->rx_idle_secs > FXP_MAX_RX_IDLE) {
                  sc->rx_idle_secs = 0;
                  fxp_mc_setup(sc);
          }
          /*
           * If there is no pending command, start another stats
           * dump. Otherwise punt for now.
           */
          if (CSR_READ_1(sc, FXP_CSR_SCB_COMMAND) == 0) {
                  /*
                   * Start another stats dump.
                   */
                  bus_dmamap_sync(sc->fxp_stag, sc->fxp_smap,
                      BUS_DMASYNC_PREREAD);
                  fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_DUMPRESET);
          } else {
                  /*
                   * A previous command is still waiting to be accepted.
                   * Just zero our copy of the stats and wait for the
                   * next timer event to update them.
                   */
                  sp->tx_good = 0;
                  sp->tx_underruns = 0;
                  sp->tx_total_collisions = 0;
  
                  sp->rx_good = 0;
                  sp->rx_crc_errors = 0;
                  sp->rx_alignment_errors = 0;
                  sp->rx_rnr_errors = 0;
                  sp->rx_overrun_errors = 0;
          }
          if (sc->miibus != NULL)
                  mii_tick(device_get_softc(sc->miibus));
  
          /*
           * Schedule another timeout one second from now.
           */
          callout_reset(&sc->stat_ch, hz, fxp_tick, sc);
          FXP_UNLOCK(sc);
          splx(s);
  }
  
  /*
   * Stop the interface. Cancels the statistics updater and resets
   * the interface.
   */
  static void
  fxp_stop(struct fxp_softc *sc)
  {
          struct ifnet *ifp = &sc->sc_if;
          struct fxp_tx *txp;
          int i;
  
          ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
          ifp->if_timer = 0;
  
  #ifdef DEVICE_POLLING
          ether_poll_deregister(ifp);
  #endif
          /*
           * Cancel stats updater.
           */
          callout_stop(&sc->stat_ch);
  
          /*
           * Issue software reset, which also unloads the microcode.
           */
          sc->flags &= ~FXP_FLAG_UCODE;
          CSR_WRITE_4(sc, FXP_CSR_PORT, FXP_PORT_SOFTWARE_RESET);
          DELAY(50);
  
          /*
           * Release any xmit buffers.
           */
          txp = sc->fxp_desc.tx_list;
          if (txp != NULL) {
                  for (i = 0; i < FXP_NTXCB; i++) {
                          if (txp[i].tx_mbuf != NULL) {
                                  bus_dmamap_sync(sc->fxp_mtag, txp[i].tx_map,
                                      BUS_DMASYNC_POSTWRITE);
                                  bus_dmamap_unload(sc->fxp_mtag, txp[i].tx_map);
                                  m_freem(txp[i].tx_mbuf);
                                  txp[i].tx_mbuf = NULL;
                                  /* clear this to reset csum offload bits */
                                  txp[i].tx_cb->tbd[0].tb_addr = 0;
                          }
                  }
          }
          bus_dmamap_sync(sc->cbl_tag, sc->cbl_map, BUS_DMASYNC_PREWRITE);
          sc->tx_queued = 0;
  }
  
  /*
   * Watchdog/transmission transmit timeout handler. Called when a
   * transmission is started on the interface, but no interrupt is
   * received before the timeout. This usually indicates that the
   * card has wedged for some reason.
   */
  static void
  fxp_watchdog(struct ifnet *ifp)
  {
          struct fxp_softc *sc = ifp->if_softc;
  
          FXP_LOCK(sc);
          device_printf(sc->dev, "device timeout\n");
          ifp->if_oerrors++;
  
          fxp_init_body(sc);
          FXP_UNLOCK(sc);
  }
  
  /*
   * Acquire locks and then call the real initialization function.  This
   * is necessary because ether_ioctl() calls if_init() and this would
   * result in mutex recursion if the mutex was held.
   */
  static void
  fxp_init(void *xsc)
  {
          struct fxp_softc *sc = xsc;
  
          FXP_LOCK(sc);
          fxp_init_body(sc);
          FXP_UNLOCK(sc);
  }
  
  /*
   * Perform device initialization. This routine must be called with the
   * softc lock held.
   */
  static void
  fxp_init_body(struct fxp_softc *sc)
  {
          struct ifnet *ifp = &sc->sc_if;
          struct fxp_cb_config *cbp;
          struct fxp_cb_ias *cb_ias;
          struct fxp_cb_tx *tcbp;
          struct fxp_tx *txp;
          struct fxp_cb_mcs *mcsp;
          int i, prm, s;
  
          FXP_LOCK_ASSERT(sc, MA_OWNED);
          s = splimp();
          /*
           * Cancel any pending I/O
           */
          fxp_stop(sc);
  
          prm = (ifp->if_flags & IFF_PROMISC) ? 1 : 0;
  
          /*
           * Initialize base of CBL and RFA memory. Loading with zero
           * sets it up for regular linear addressing.
           */
          CSR_WRITE_4(sc, FXP_CSR_SCB_GENERAL, 0);
          fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_BASE);
  
          fxp_scb_wait(sc);
          fxp_scb_cmd(sc, FXP_SCB_COMMAND_RU_BASE);
  
          /*
           * Initialize base of dump-stats buffer.
           */
          fxp_scb_wait(sc);
          bus_dmamap_sync(sc->fxp_stag, sc->fxp_smap, BUS_DMASYNC_PREREAD);
          CSR_WRITE_4(sc, FXP_CSR_SCB_GENERAL, sc->stats_addr);
          fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_DUMP_ADR);
  
          /*
           * Attempt to load microcode if requested.
           */
          if (ifp->if_flags & IFF_LINK0 && (sc->flags & FXP_FLAG_UCODE) == 0)
                  fxp_load_ucode(sc);
  
          /*
           * Initialize the multicast address list.
           */
          if (fxp_mc_addrs(sc)) {
                  mcsp = sc->mcsp;
                  mcsp->cb_status = 0;
                  mcsp->cb_command =
                      htole16(FXP_CB_COMMAND_MCAS | FXP_CB_COMMAND_EL);
                  mcsp->link_addr = 0xffffffff;
                  /*
                   * Start the multicast setup command.
                   */
                  fxp_scb_wait(sc);
                  bus_dmamap_sync(sc->mcs_tag, sc->mcs_map, BUS_DMASYNC_PREWRITE);
                  CSR_WRITE_4(sc, FXP_CSR_SCB_GENERAL, sc->mcs_addr);
                  fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_START);
                  /* ...and wait for it to complete. */
                  fxp_dma_wait(sc, &mcsp->cb_status, sc->mcs_tag, sc->mcs_map);
                  bus_dmamap_sync(sc->mcs_tag, sc->mcs_map,
                      BUS_DMASYNC_POSTWRITE);
          }
  
          /*
           * We temporarily use memory that contains the TxCB list to
           * construct the config CB. The TxCB list memory is rebuilt
           * later.
           */
          cbp = (struct fxp_cb_config *)sc->fxp_desc.cbl_list;
  
          /*
           * This bcopy is kind of disgusting, but there are a bunch of must be
           * zero and must be one bits in this structure and this is the easiest
           * way to initialize them all to proper values.
           */
          bcopy(fxp_cb_config_template, cbp, sizeof(fxp_cb_config_template));
  
          cbp->cb_status =        0;
          cbp->cb_command =       htole16(FXP_CB_COMMAND_CONFIG |
              FXP_CB_COMMAND_EL);
          cbp->link_addr =        0xffffffff;     /* (no) next command */
          cbp->byte_count =       sc->flags & FXP_FLAG_EXT_RFA ? 32 : 22;
          cbp->rx_fifo_limit =    8;      /* rx fifo threshold (32 bytes) */
          cbp->tx_fifo_limit =    0;      /* tx fifo threshold (0 bytes) */
          cbp->adaptive_ifs =     0;      /* (no) adaptive interframe spacing */
          cbp->mwi_enable =       sc->flags & FXP_FLAG_MWI_ENABLE ? 1 : 0;
          cbp->type_enable =      0;      /* actually reserved */
          cbp->read_align_en =    sc->flags & FXP_FLAG_READ_ALIGN ? 1 : 0;
          cbp->end_wr_on_cl =     sc->flags & FXP_FLAG_WRITE_ALIGN ? 1 : 0;
          cbp->rx_dma_bytecount = 0;      /* (no) rx DMA max */
          cbp->tx_dma_bytecount = 0;      /* (no) tx DMA max */
          cbp->dma_mbce =         0;      /* (disable) dma max counters */
          cbp->late_scb =         0;      /* (don't) defer SCB update */
          cbp->direct_dma_dis =   1;      /* disable direct rcv dma mode */
          cbp->tno_int_or_tco_en =0;      /* (disable) tx not okay interrupt */
          cbp->ci_int =           1;      /* interrupt on CU idle */
          cbp->ext_txcb_dis =     sc->flags & FXP_FLAG_EXT_TXCB ? 0 : 1;
          cbp->ext_stats_dis =    1;      /* disable extended counters */
          cbp->keep_overrun_rx =  0;      /* don't pass overrun frames to host */
          cbp->save_bf =          sc->flags & FXP_FLAG_SAVE_BAD ? 1 : prm;
          cbp->disc_short_rx =    !prm;   /* discard short packets */
          cbp->underrun_retry =   1;      /* retry mode (once) on DMA underrun */
          cbp->two_frames =       0;      /* do not limit FIFO to 2 frames */
          cbp->dyn_tbd =          0;      /* (no) dynamic TBD mode */
          cbp->ext_rfa =          sc->flags & FXP_FLAG_EXT_RFA ? 1 : 0;
          cbp->mediatype =        sc->flags & FXP_FLAG_SERIAL_MEDIA ? 0 : 1;
          cbp->csma_dis =         0;      /* (don't) disable link */
          cbp->tcp_udp_cksum =    0;      /* (don't) enable checksum */
          cbp->vlan_tco =         0;      /* (don't) enable vlan wakeup */
          cbp->link_wake_en =     0;      /* (don't) assert PME# on link change */
          cbp->arp_wake_en =      0;      /* (don't) assert PME# on arp */
          cbp->mc_wake_en =       0;      /* (don't) enable PME# on mcmatch */
          cbp->nsai =             1;      /* (don't) disable source addr insert */
          cbp->preamble_length =  2;      /* (7 byte) preamble */
          cbp->loopback =         0;      /* (don't) loopback */
          cbp->linear_priority =  0;      /* (normal CSMA/CD operation) */
          cbp->linear_pri_mode =  0;      /* (wait after xmit only) */
          cbp->interfrm_spacing = 6;      /* (96 bits of) interframe spacing */
          cbp->promiscuous =      prm;    /* promiscuous mode */
          cbp->bcast_disable =    0;      /* (don't) disable broadcasts */
          cbp->wait_after_win =   0;      /* (don't) enable modified backoff alg*/
          cbp->ignore_ul =        0;      /* consider U/L bit in IA matching */
          cbp->crc16_en =         0;      /* (don't) enable crc-16 algorithm */
          cbp->crscdt =           sc->flags & FXP_FLAG_SERIAL_MEDIA ? 1 : 0;
  
          cbp->stripping =        !prm;   /* truncate rx packet to byte count */
          cbp->padding =          1;      /* (do) pad short tx packets */
          cbp->rcv_crc_xfer =     0;      /* (don't) xfer CRC to host */
          cbp->long_rx_en =       sc->flags & FXP_FLAG_LONG_PKT_EN ? 1 : 0;
          cbp->ia_wake_en =       0;      /* (don't) wake up on address match */
          cbp->magic_pkt_dis =    0;      /* (don't) disable magic packet */
                                          /* must set wake_en in PMCSR also */
          cbp->force_fdx =        0;      /* (don't) force full duplex */
          cbp->fdx_pin_en =       1;      /* (enable) FDX# pin */
          cbp->multi_ia =         0;      /* (don't) accept multiple IAs */
          cbp->mc_all =           sc->flags & FXP_FLAG_ALL_MCAST ? 1 : 0;
          cbp->gamla_rx =         sc->flags & FXP_FLAG_EXT_RFA ? 1 : 0;
  
          if (sc->tunable_noflow || sc->revision == FXP_REV_82557) {
                  /*
                   * The 82557 has no hardware flow control, the values
                   * below are the defaults for the chip.
                   */
                  cbp->fc_delay_lsb =     0;
                  cbp->fc_delay_msb =     0x40;
                  cbp->pri_fc_thresh =    3;
                  cbp->tx_fc_dis =        0;
                  cbp->rx_fc_restop =     0;
                  cbp->rx_fc_restart =    0;
                  cbp->fc_filter =        0;
                  cbp->pri_fc_loc =       1;
          } else {
                  cbp->fc_delay_lsb =     0x1f;
                  cbp->fc_delay_msb =     0x01;
                  cbp->pri_fc_thresh =    3;
                  cbp->tx_fc_dis =        0;      /* enable transmit FC */
                  cbp->rx_fc_restop =     1;      /* enable FC restop frames */
                  cbp->rx_fc_restart =    1;      /* enable FC restart frames */
                  cbp->fc_filter =        !prm;   /* drop FC frames to host */
                  cbp->pri_fc_loc =       1;      /* FC pri location (byte31) */
          }
  
          /*
           * Start the config command/DMA.
           */
          fxp_scb_wait(sc);
          bus_dmamap_sync(sc->cbl_tag, sc->cbl_map, BUS_DMASYNC_PREWRITE);
          CSR_WRITE_4(sc, FXP_CSR_SCB_GENERAL, sc->fxp_desc.cbl_addr);
          fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_START);
          /* ...and wait for it to complete. */
          fxp_dma_wait(sc, &cbp->cb_status, sc->cbl_tag, sc->cbl_map);
          bus_dmamap_sync(sc->cbl_tag, sc->cbl_map, BUS_DMASYNC_POSTWRITE);
  
          /*
           * Now initialize the station address. Temporarily use the TxCB
           * memory area like we did above for the config CB.
           */
          cb_ias = (struct fxp_cb_ias *)sc->fxp_desc.cbl_list;
          cb_ias->cb_status = 0;
          cb_ias->cb_command = htole16(FXP_CB_COMMAND_IAS | FXP_CB_COMMAND_EL);
          cb_ias->link_addr = 0xffffffff;
          bcopy(sc->arpcom.ac_enaddr, cb_ias->macaddr,
              sizeof(sc->arpcom.ac_enaddr));
  
          /*
           * Start the IAS (Individual Address Setup) command/DMA.
           */
          fxp_scb_wait(sc);
          bus_dmamap_sync(sc->cbl_tag, sc->cbl_map, BUS_DMASYNC_PREWRITE);
          fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_START);
          /* ...and wait for it to complete. */
          fxp_dma_wait(sc, &cb_ias->cb_status, sc->cbl_tag, sc->cbl_map);
          bus_dmamap_sync(sc->cbl_tag, sc->cbl_map, BUS_DMASYNC_POSTWRITE);
  
          /*
           * Initialize transmit control block (TxCB) list.
           */
          txp = sc->fxp_desc.tx_list;
          tcbp = sc->fxp_desc.cbl_list;
          bzero(tcbp, FXP_TXCB_SZ);
          for (i = 0; i < FXP_NTXCB; i++) {
                  txp[i].tx_mbuf = NULL;
                  tcbp[i].cb_status = htole16(FXP_CB_STATUS_C | FXP_CB_STATUS_OK);
                  tcbp[i].cb_command = htole16(FXP_CB_COMMAND_NOP);
                  tcbp[i].link_addr = htole32(sc->fxp_desc.cbl_addr +
                      (((i + 1) & FXP_TXCB_MASK) * sizeof(struct fxp_cb_tx)));
                  if (sc->flags & FXP_FLAG_EXT_TXCB)
                          tcbp[i].tbd_array_addr =
                              htole32(FXP_TXCB_DMA_ADDR(sc, &tcbp[i].tbd[2]));
                  else
                          tcbp[i].tbd_array_addr =
                              htole32(FXP_TXCB_DMA_ADDR(sc, &tcbp[i].tbd[0]));
                  txp[i].tx_next = &txp[(i + 1) & FXP_TXCB_MASK];
          }
          /*
           * Set the suspend flag on the first TxCB and start the control
           * unit. It will execute the NOP and then suspend.
           */
          tcbp->cb_command = htole16(FXP_CB_COMMAND_NOP | FXP_CB_COMMAND_S);
          bus_dmamap_sync(sc->cbl_tag, sc->cbl_map, BUS_DMASYNC_PREWRITE);
          sc->fxp_desc.tx_first = sc->fxp_desc.tx_last = txp;
          sc->tx_queued = 1;
  
          fxp_scb_wait(sc);
          fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_START);
  
          /*
           * Initialize receiver buffer area - RFA.
           */
          fxp_scb_wait(sc);
          CSR_WRITE_4(sc, FXP_CSR_SCB_GENERAL, sc->fxp_desc.rx_head->rx_addr);
          fxp_scb_cmd(sc, FXP_SCB_COMMAND_RU_START);
  
          /*
           * Set current media.
           */
          if (sc->miibus != NULL)
                  mii_mediachg(device_get_softc(sc->miibus));
  
          ifp->if_flags |= IFF_RUNNING;
          ifp->if_flags &= ~IFF_OACTIVE;
  
          /*
           * Enable interrupts.
           */
  #ifdef DEVICE_POLLING
          /*
           * ... but only do that if we are not polling. And because (presumably)
           * the default is interrupts on, we need to disable them explicitly!
           */
          if ( ifp->if_flags & IFF_POLLING )
                  CSR_WRITE_1(sc, FXP_CSR_SCB_INTRCNTL, FXP_SCB_INTR_DISABLE);
          else
  #endif /* DEVICE_POLLING */
          CSR_WRITE_1(sc, FXP_CSR_SCB_INTRCNTL, 0);
  
          /*
           * Start stats updater.
           */
          callout_reset(&sc->stat_ch, hz, fxp_tick, sc);
          splx(s);
  }
  
  static int
  fxp_serial_ifmedia_upd(struct ifnet *ifp)
  {
  
          return (0);
  }
  
  static void
  fxp_serial_ifmedia_sts(struct ifnet *ifp, struct ifmediareq *ifmr)
  {
  
          ifmr->ifm_active = IFM_ETHER|IFM_MANUAL;
  }
  
  /*
   * Change media according to request.
   */
  static int
  fxp_ifmedia_upd(struct ifnet *ifp)
  {
          struct fxp_softc *sc = ifp->if_softc;
          struct mii_data *mii;
  
          mii = device_get_softc(sc->miibus);
          mii_mediachg(mii);
          return (0);
  }
  
  /*
   * Notify the world which media we're using.
   */
  static void
  fxp_ifmedia_sts(struct ifnet *ifp, struct ifmediareq *ifmr)
  {
          struct fxp_softc *sc = ifp->if_softc;
          struct mii_data *mii;
  
          mii = device_get_softc(sc->miibus);
          mii_pollstat(mii);
          ifmr->ifm_active = mii->mii_media_active;
          ifmr->ifm_status = mii->mii_media_status;
  
          if (ifmr->ifm_status & IFM_10_T && sc->flags & FXP_FLAG_CU_RESUME_BUG)
                  sc->cu_resume_bug = 1;
          else
                  sc->cu_resume_bug = 0;
  }
  
  /*
   * Add a buffer to the end of the RFA buffer list.
   * Return 0 if successful, 1 for failure. A failure results in
   * adding the 'oldm' (if non-NULL) on to the end of the list -
   * tossing out its old contents and recycling it.
   * The RFA struct is stuck at the beginning of mbuf cluster and the
   * data pointer is fixed up to point just past it.
   */
  static int
  fxp_add_rfabuf(struct fxp_softc *sc, struct fxp_rx *rxp)
  {
          struct mbuf *m;
          struct fxp_rfa *rfa, *p_rfa;
          struct fxp_rx *p_rx;
          bus_dmamap_t tmp_map;
          int error;
  
          m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
          if (m == NULL)
                  return (ENOBUFS);
  
          /*
           * Move the data pointer up so that the incoming data packet
           * will be 32-bit aligned.
           */
          m->m_data += RFA_ALIGNMENT_FUDGE;
  
          /*
           * Get a pointer to the base of the mbuf cluster and move
           * data start past it.
           */
          rfa = mtod(m, struct fxp_rfa *);
          m->m_data += sc->rfa_size;
          rfa->size = htole16(MCLBYTES - sc->rfa_size - RFA_ALIGNMENT_FUDGE);
  
          rfa->rfa_status = 0;
          rfa->rfa_control = htole16(FXP_RFA_CONTROL_EL);
          rfa->actual_size = 0;
  
          /*
           * Initialize the rest of the RFA.  Note that since the RFA
           * is misaligned, we cannot store values directly.  We're thus
           * using the le32enc() function which handles endianness and
           * is also alignment-safe.
           */
          le32enc(&rfa->link_addr, 0xffffffff);
          le32enc(&rfa->rbd_addr, 0xffffffff);
  
          /* Map the RFA into DMA memory. */
          error = bus_dmamap_load(sc->fxp_mtag, sc->spare_map, rfa,
              MCLBYTES - RFA_ALIGNMENT_FUDGE, fxp_dma_map_addr,
              &rxp->rx_addr, 0);
          if (error) {
                  m_freem(m);
                  return (error);
          }
  
          bus_dmamap_unload(sc->fxp_mtag, rxp->rx_map);
          tmp_map = sc->spare_map;
          sc->spare_map = rxp->rx_map;
          rxp->rx_map = tmp_map;
          rxp->rx_mbuf = m;
  
          bus_dmamap_sync(sc->fxp_mtag, rxp->rx_map,
              BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
  
          /*
           * If there are other buffers already on the list, attach this
           * one to the end by fixing up the tail to point to this one.
           */
          if (sc->fxp_desc.rx_head != NULL) {
                  p_rx = sc->fxp_desc.rx_tail;
                  p_rfa = (struct fxp_rfa *)
                      (p_rx->rx_mbuf->m_ext.ext_buf + RFA_ALIGNMENT_FUDGE);
                  p_rx->rx_next = rxp;
                  le32enc(&p_rfa->link_addr, rxp->rx_addr);
                  p_rfa->rfa_control = 0;
                  bus_dmamap_sync(sc->fxp_mtag, p_rx->rx_map,
                      BUS_DMASYNC_PREWRITE);
          } else {
                  rxp->rx_next = NULL;
                  sc->fxp_desc.rx_head = rxp;
          }
          sc->fxp_desc.rx_tail = rxp;
          return (0);
  }
  
  static volatile int
  fxp_miibus_readreg(device_t dev, int phy, int reg)
  {
          struct fxp_softc *sc = device_get_softc(dev);
          int count = 10000;
          int value;
  
          CSR_WRITE_4(sc, FXP_CSR_MDICONTROL,
              (FXP_MDI_READ << 26) | (reg << 16) | (phy << 21));
  
          while (((value = CSR_READ_4(sc, FXP_CSR_MDICONTROL)) & 0x10000000) == 0
              && count--)
                  DELAY(10);
  
          if (count <= 0)
                  device_printf(dev, "fxp_miibus_readreg: timed out\n");
  
          return (value & 0xffff);
  }
  
  static void
  fxp_miibus_writereg(device_t dev, int phy, int reg, int value)
  {
          struct fxp_softc *sc = device_get_softc(dev);
          int count = 10000;
  
          CSR_WRITE_4(sc, FXP_CSR_MDICONTROL,
              (FXP_MDI_WRITE << 26) | (reg << 16) | (phy << 21) |
              (value & 0xffff));
  
          while ((CSR_READ_4(sc, FXP_CSR_MDICONTROL) & 0x10000000) == 0 &&
              count--)
                  DELAY(10);
  
          if (count <= 0)
                  device_printf(dev, "fxp_miibus_writereg: timed out\n");
  }
  
  static int
  fxp_ioctl(struct ifnet *ifp, u_long command, caddr_t data)
  {
          struct fxp_softc *sc = ifp->if_softc;
          struct ifreq *ifr = (struct ifreq *)data;
          struct mii_data *mii;
          int flag, mask, s, error = 0;
  
          /*
           * Detaching causes us to call ioctl with the mutex owned.  Preclude
           * that by saying we're busy if the lock is already held.
           */
          if (FXP_LOCKED(sc))
                  return (EBUSY);
  
          FXP_LOCK(sc);
          s = splimp();
  
          switch (command) {
          case SIOCSIFFLAGS:
                  if (ifp->if_flags & IFF_ALLMULTI)
                          sc->flags |= FXP_FLAG_ALL_MCAST;
                  else
                          sc->flags &= ~FXP_FLAG_ALL_MCAST;
  
                  /*
                   * If interface is marked up and not running, then start it.
                   * If it is marked down and running, stop it.
                   * XXX If it's up then re-initialize it. This is so flags
                   * such as IFF_PROMISC are handled.
                   */
                  if (ifp->if_flags & IFF_UP) {
                          fxp_init_body(sc);
                  } else {
                          if (ifp->if_flags & IFF_RUNNING)
                                  fxp_stop(sc);
                  }
                  break;
  
          case SIOCADDMULTI:
          case SIOCDELMULTI:
                  if (ifp->if_flags & IFF_ALLMULTI)
                          sc->flags |= FXP_FLAG_ALL_MCAST;
                  else
                          sc->flags &= ~FXP_FLAG_ALL_MCAST;
                  /*
                   * Multicast list has changed; set the hardware filter
                   * accordingly.
                   */
                  if ((sc->flags & FXP_FLAG_ALL_MCAST) == 0)
                          fxp_mc_setup(sc);
                  /*
                   * fxp_mc_setup() can set FXP_FLAG_ALL_MCAST, so check it
                   * again rather than else {}.
                   */
                  if (sc->flags & FXP_FLAG_ALL_MCAST)
                          fxp_init_body(sc);
                  error = 0;
                  break;
  
          case SIOCSIFMEDIA:
          case SIOCGIFMEDIA:
                  if (sc->miibus != NULL) {
                          mii = device_get_softc(sc->miibus);
                          error = ifmedia_ioctl(ifp, ifr,
                              &mii->mii_media, command);
                  } else {
                          error = ifmedia_ioctl(ifp, ifr, &sc->sc_media, command);
                  }
                  break;
  
          case SIOCSIFCAP:
                  mask = ifp->if_capenable ^ ifr->ifr_reqcap;
                  if (mask & IFCAP_POLLING)
                          ifp->if_capenable ^= IFCAP_POLLING;
                  if (mask & IFCAP_VLAN_MTU) {
                          ifp->if_capenable ^= IFCAP_VLAN_MTU;
                          if (sc->revision != FXP_REV_82557)
                                  flag = FXP_FLAG_LONG_PKT_EN;
                          else /* a hack to get long frames on the old chip */
                                  flag = FXP_FLAG_SAVE_BAD;
                          sc->flags ^= flag;
                          if (ifp->if_flags & IFF_UP)
                                  fxp_init_body(sc);
                  }
                  break;
  
          default:
                  /* 
                   * ether_ioctl() will eventually call fxp_start() which
                   * will result in mutex recursion so drop it first.
                   */
                  FXP_UNLOCK(sc);
                  error = ether_ioctl(ifp, command, data);
          }
          if (FXP_LOCKED(sc))
                  FXP_UNLOCK(sc);
          splx(s);
          return (error);
  }
  
  /*
   * Fill in the multicast address list and return number of entries.
   */
  static int
  fxp_mc_addrs(struct fxp_softc *sc)
  {
          struct fxp_cb_mcs *mcsp = sc->mcsp;
          struct ifnet *ifp = &sc->sc_if;
          struct ifmultiaddr *ifma;
          int nmcasts;
  
          nmcasts = 0;
          if ((sc->flags & FXP_FLAG_ALL_MCAST) == 0) {
                  IF_ADDR_LOCK(ifp);
  #if __FreeBSD_version < 500000
                  LIST_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
  #else
                  TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
  #endif
                          if (ifma->ifma_addr->sa_family != AF_LINK)
                                  continue;
                          if (nmcasts >= MAXMCADDR) {
                                  sc->flags |= FXP_FLAG_ALL_MCAST;
                                  nmcasts = 0;
                                  break;
                          }
                          bcopy(LLADDR((struct sockaddr_dl *)ifma->ifma_addr),
                              &sc->mcsp->mc_addr[nmcasts][0], ETHER_ADDR_LEN);
                          nmcasts++;
                  }
                  IF_ADDR_UNLOCK(ifp);
          }
          mcsp->mc_cnt = htole16(nmcasts * ETHER_ADDR_LEN);
          return (nmcasts);
  }
  
  /*
   * Program the multicast filter.
   *
   * We have an artificial restriction that the multicast setup command
   * must be the first command in the chain, so we take steps to ensure
   * this. By requiring this, it allows us to keep up the performance of
   * the pre-initialized command ring (esp. link pointers) by not actually
   * inserting the mcsetup command in the ring - i.e. its link pointer
   * points to the TxCB ring, but the mcsetup descriptor itself is not part
   * of it. We then can do 'CU_START' on the mcsetup descriptor and have it
   * lead into the regular TxCB ring when it completes.
   *
   * This function must be called at splimp.
   */
  static void
  fxp_mc_setup(struct fxp_softc *sc)
  {
          struct fxp_cb_mcs *mcsp = sc->mcsp;
          struct ifnet *ifp = &sc->sc_if;
          struct fxp_tx *txp;
          int count;
  
          FXP_LOCK_ASSERT(sc, MA_OWNED);
          /*
           * If there are queued commands, we must wait until they are all
           * completed. If we are already waiting, then add a NOP command
           * with interrupt option so that we're notified when all commands
           * have been completed - fxp_start() ensures that no additional
           * TX commands will be added when need_mcsetup is true.
           */
          if (sc->tx_queued) {
                  /*
                   * need_mcsetup will be true if we are already waiting for the
                   * NOP command to be completed (see below). In this case, bail.
                   */
                  if (sc->need_mcsetup)
                          return;
                  sc->need_mcsetup = 1;
  
                  /*
                   * Add a NOP command with interrupt so that we are notified
                   * when all TX commands have been processed.
                   */
                  txp = sc->fxp_desc.tx_last->tx_next;
                  txp->tx_mbuf = NULL;
                  txp->tx_cb->cb_status = 0;
                  txp->tx_cb->cb_command = htole16(FXP_CB_COMMAND_NOP |
                      FXP_CB_COMMAND_S | FXP_CB_COMMAND_I);
                  /*
                   * Advance the end of list forward.
                   */
                  sc->fxp_desc.tx_last->tx_cb->cb_command &=
                      htole16(~FXP_CB_COMMAND_S);
                  bus_dmamap_sync(sc->cbl_tag, sc->cbl_map, BUS_DMASYNC_PREWRITE);
                  sc->fxp_desc.tx_last = txp;
                  sc->tx_queued++;
                  /*
                   * Issue a resume in case the CU has just suspended.
                   */
                  fxp_scb_wait(sc);
                  fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_RESUME);
                  /*
                   * Set a 5 second timer just in case we don't hear from the
                   * card again.
                   */
                  ifp->if_timer = 5;
  
                  return;
          }
          sc->need_mcsetup = 0;
  
          /*
           * Initialize multicast setup descriptor.
           */
          mcsp->cb_status = 0;
          mcsp->cb_command = htole16(FXP_CB_COMMAND_MCAS |
              FXP_CB_COMMAND_S | FXP_CB_COMMAND_I);
          mcsp->link_addr = htole32(sc->fxp_desc.cbl_addr);
          txp = &sc->fxp_desc.mcs_tx;
          txp->tx_mbuf = NULL;
          txp->tx_cb = (struct fxp_cb_tx *)sc->mcsp;
          txp->tx_next = sc->fxp_desc.tx_list;
          (void) fxp_mc_addrs(sc);
          sc->fxp_desc.tx_first = sc->fxp_desc.tx_last = txp;
          sc->tx_queued = 1;
  
          /*
           * Wait until command unit is not active. This should never
           * be the case when nothing is queued, but make sure anyway.
           */
          count = 100;
          while ((CSR_READ_1(sc, FXP_CSR_SCB_RUSCUS) >> 6) ==
              FXP_SCB_CUS_ACTIVE && --count)
                  DELAY(10);
          if (count == 0) {
                  device_printf(sc->dev, "command queue timeout\n");
                  return;
          }
  
          /*
           * Start the multicast setup command.
           */
          fxp_scb_wait(sc);
          bus_dmamap_sync(sc->mcs_tag, sc->mcs_map, BUS_DMASYNC_PREWRITE);
          CSR_WRITE_4(sc, FXP_CSR_SCB_GENERAL, sc->mcs_addr);
          fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_START);
  
          ifp->if_timer = 2;
          return;
  }
  
  static uint32_t fxp_ucode_d101a[] = D101_A_RCVBUNDLE_UCODE;
  static uint32_t fxp_ucode_d101b0[] = D101_B0_RCVBUNDLE_UCODE;
  static uint32_t fxp_ucode_d101ma[] = D101M_B_RCVBUNDLE_UCODE;
  static uint32_t fxp_ucode_d101s[] = D101S_RCVBUNDLE_UCODE;
  static uint32_t fxp_ucode_d102[] = D102_B_RCVBUNDLE_UCODE;
  static uint32_t fxp_ucode_d102c[] = D102_C_RCVBUNDLE_UCODE;
  
  #define UCODE(x)        x, sizeof(x)/sizeof(uint32_t)
  
  struct ucode {
          uint32_t        revision;
          uint32_t        *ucode;
          int             length;
          u_short         int_delay_offset;
          u_short         bundle_max_offset;
  } ucode_table[] = {
          { FXP_REV_82558_A4, UCODE(fxp_ucode_d101a), D101_CPUSAVER_DWORD, 0 },
          { FXP_REV_82558_B0, UCODE(fxp_ucode_d101b0), D101_CPUSAVER_DWORD, 0 },
          { FXP_REV_82559_A0, UCODE(fxp_ucode_d101ma),
              D101M_CPUSAVER_DWORD, D101M_CPUSAVER_BUNDLE_MAX_DWORD },
          { FXP_REV_82559S_A, UCODE(fxp_ucode_d101s),
              D101S_CPUSAVER_DWORD, D101S_CPUSAVER_BUNDLE_MAX_DWORD },
          { FXP_REV_82550, UCODE(fxp_ucode_d102),
              D102_B_CPUSAVER_DWORD, D102_B_CPUSAVER_BUNDLE_MAX_DWORD },
          { FXP_REV_82550_C, UCODE(fxp_ucode_d102c),
              D102_C_CPUSAVER_DWORD, D102_C_CPUSAVER_BUNDLE_MAX_DWORD },
          { 0, NULL, 0, 0, 0 }
  };
  
  static void
  fxp_load_ucode(struct fxp_softc *sc)
  {
          struct ucode *uc;
          struct fxp_cb_ucode *cbp;
          int i;
  
          for (uc = ucode_table; uc->ucode != NULL; uc++)
                  if (sc->revision == uc->revision)
                          break;
          if (uc->ucode == NULL)
                  return;
          cbp = (struct fxp_cb_ucode *)sc->fxp_desc.cbl_list;
          cbp->cb_status = 0;
          cbp->cb_command = htole16(FXP_CB_COMMAND_UCODE | FXP_CB_COMMAND_EL);
          cbp->link_addr = 0xffffffff;            /* (no) next command */
          for (i = 0; i < uc->length; i++)
                  cbp->ucode[i] = htole32(uc->ucode[i]);
          if (uc->int_delay_offset)
                  *(uint16_t *)&cbp->ucode[uc->int_delay_offset] =
                      htole16(sc->tunable_int_delay + sc->tunable_int_delay / 2);
          if (uc->bundle_max_offset)
                  *(uint16_t *)&cbp->ucode[uc->bundle_max_offset] =
                      htole16(sc->tunable_bundle_max);
          /*
           * Download the ucode to the chip.
           */
          fxp_scb_wait(sc);
          bus_dmamap_sync(sc->cbl_tag, sc->cbl_map, BUS_DMASYNC_PREWRITE);
          CSR_WRITE_4(sc, FXP_CSR_SCB_GENERAL, sc->fxp_desc.cbl_addr);
          fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_START);
          /* ...and wait for it to complete. */
          fxp_dma_wait(sc, &cbp->cb_status, sc->cbl_tag, sc->cbl_map);
          bus_dmamap_sync(sc->cbl_tag, sc->cbl_map, BUS_DMASYNC_POSTWRITE);
          device_printf(sc->dev,
              "Microcode loaded, int_delay: %d usec  bundle_max: %d\n",
              sc->tunable_int_delay, 
              uc->bundle_max_offset == 0 ? 0 : sc->tunable_bundle_max);
          sc->flags |= FXP_FLAG_UCODE;
  }
  
  static int
  sysctl_int_range(SYSCTL_HANDLER_ARGS, int low, int high)
  {
          int error, value;
  
          value = *(int *)arg1;
          error = sysctl_handle_int(oidp, &value, 0, req);
          if (error || !req->newptr)
                  return (error);
          if (value < low || value > high)
                  return (EINVAL);
          *(int *)arg1 = value;
          return (0);
  }
  
  /*
   * Interrupt delay is expressed in microseconds, a multiplier is used
   * to convert this to the appropriate clock ticks before using. 
   */
  static int
  sysctl_hw_fxp_int_delay(SYSCTL_HANDLER_ARGS)
  {
          return (sysctl_int_range(oidp, arg1, arg2, req, 300, 3000));
  }
  
  static int
  sysctl_hw_fxp_bundle_max(SYSCTL_HANDLER_ARGS)
  {
          return (sysctl_int_range(oidp, arg1, arg2, req, 1, 0xffff));
  }

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