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/*
 * Realtek 8139 (but not the 8129).
 * Error recovery for the various over/under -flow conditions
 * may need work.
 */
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
#include "../port/error.h"
#include "../port/netif.h"

#include "etherif.h"

enum {                                  /* registers */
        Idr0            = 0x0000,       /* MAC address */
        Mar0            = 0x0008,       /* Multicast address */
        Tsd0            = 0x0010,       /* Transmit Status Descriptor0 */
        Tsad0           = 0x0020,       /* Transmit Start Address Descriptor0 */
        Rbstart         = 0x0030,       /* Receive Buffer Start Address */
        Erbcr           = 0x0034,       /* Early Receive Byte Count */
        Ersr            = 0x0036,       /* Early Receive Status */
        Cr              = 0x0037,       /* Command Register */
        Capr            = 0x0038,       /* Current Address of Packet Read */
        Cbr             = 0x003A,       /* Current Buffer Address */
        Imr             = 0x003C,       /* Interrupt Mask */
        Isr             = 0x003E,       /* Interrupt Status */
        Tcr             = 0x0040,       /* Transmit Configuration */
        Rcr             = 0x0044,       /* Receive Configuration */
        Tctr            = 0x0048,       /* Timer Count */
        Mpc             = 0x004C,       /* Missed Packet Counter */
        Cr9346          = 0x0050,       /* 9346 Command Register */
        Config0         = 0x0051,       /* Configuration Register 0 */
        Config1         = 0x0052,       /* Configuration Register 1 */
        TimerInt        = 0x0054,       /* Timer Interrupt */
        Msr             = 0x0058,       /* Media Status */
        Config3         = 0x0059,       /* Configuration Register 3 */
        Config4         = 0x005A,       /* Configuration Register 4 */
        Mulint          = 0x005C,       /* Multiple Interrupt Select */
        RerID           = 0x005E,       /* PCI Revision ID */
        Tsad            = 0x0060,       /* Transmit Status of all Descriptors */

        Bmcr            = 0x0062,       /* Basic Mode Control */
        Bmsr            = 0x0064,       /* Basic Mode Status */
        Anar            = 0x0066,       /* Auto-Negotiation Advertisment */
        Anlpar          = 0x0068,       /* Auto-Negotiation Link Partner */
        Aner            = 0x006A,       /* Auto-Negotiation Expansion */
        Dis             = 0x006C,       /* Disconnect Counter */
        Fcsc            = 0x006E,       /* False Carrier Sense Counter */
        Nwaytr          = 0x0070,       /* N-way Test */
        Rec             = 0x0072,       /* RX_ER Counter */
        Cscr            = 0x0074,       /* CS Configuration */
        Phy1parm        = 0x0078,       /* PHY Parameter 1 */
        Twparm          = 0x007C,       /* Twister Parameter */
        Phy2parm        = 0x0080,       /* PHY Parameter 2 */
};

enum {                                  /* Cr */
        Bufe            = 0x01,         /* Rx Buffer Empty */
        Te              = 0x04,         /* Transmitter Enable */
        Re              = 0x08,         /* Receiver Enable */
        Rst             = 0x10,         /* Software Reset */
};

enum {                                  /* Imr/Isr */
        Rok             = 0x0001,       /* Receive OK */
        Rer             = 0x0002,       /* Receive Error */
        Tok             = 0x0004,       /* Transmit OK */
        Ter             = 0x0008,       /* Transmit Error */
        Rxovw           = 0x0010,       /* Receive Buffer Overflow */
        PunLc           = 0x0020,       /* Packet Underrun or Link Change */
        Fovw            = 0x0040,       /* Receive FIFO Overflow */
        Clc             = 0x2000,       /* Cable Length Change */
        Timerbit        = 0x4000,       /* Timer */
        Serr            = 0x8000,       /* System Error */
};

enum {                                  /* Tcr */
        Clrabt          = 0x00000001,   /* Clear Abort */
        TxrrSHIFT       = 4,            /* Transmit Retry Count */
        TxrrMASK        = 0x000000F0,
        MtxdmaSHIFT     = 8,            /* Max. DMA Burst Size */
        MtxdmaMASK      = 0x00000700,
        Mtxdma2048      = 0x00000700,
        Acrc            = 0x00010000,   /* Append CRC (not) */
        LbkSHIFT        = 17,           /* Loopback Test */
        LbkMASK         = 0x00060000,
        Rtl8139ArevG    = 0x00800000,   /* RTL8139A Rev. G ID */
        IfgSHIFT        = 24,           /* Interframe Gap */
        IfgMASK         = 0x03000000,
        HwveridSHIFT    = 26,           /* Hardware Version ID */
        HwveridMASK     = 0x7C000000,
};

enum {                                  /* Rcr */
        Aap             = 0x00000001,   /* Accept All Packets */
        Apm             = 0x00000002,   /* Accept Physical Match */
        Am              = 0x00000004,   /* Accept Multicast */
        Ab              = 0x00000008,   /* Accept Broadcast */
        Ar              = 0x00000010,   /* Accept Runt */
        Aer             = 0x00000020,   /* Accept Error */
        Sel9356         = 0x00000040,   /* 9356 EEPROM used */
        Wrap            = 0x00000080,   /* Rx Buffer Wrap Control */
        MrxdmaSHIFT     = 8,            /* Max. DMA Burst Size */
        MrxdmaMASK      = 0x00000700,
        Mrxdmaunlimited = 0x00000700,
        RblenSHIFT      = 11,           /* Receive Buffer Length */
        RblenMASK       = 0x00001800,
        Rblen8K         = 0x00000000,   /* 8KB+16 */
        Rblen16K        = 0x00000800,   /* 16KB+16 */
        Rblen32K        = 0x00001000,   /* 32KB+16 */
        Rblen64K        = 0x00001800,   /* 64KB+16 */
        RxfthSHIFT      = 13,           /* Receive Buffer Length */
        RxfthMASK       = 0x0000E000,
        Rxfth256        = 0x00008000,
        Rxfthnone       = 0x0000E000,
        Rer8            = 0x00010000,   /* Accept Error Packets > 8 bytes */
        MulERINT        = 0x00020000,   /* Multiple Early Interrupt Select */
        ErxthSHIFT      = 24,           /* Early Rx Threshold */
        ErxthMASK       = 0x0F000000,
        Erxthnone       = 0x00000000,
};

enum {                                  /* Received Packet Status */
        Rcok            = 0x0001,       /* Receive Completed OK */
        Fae             = 0x0002,       /* Frame Alignment Error */
        Crc             = 0x0004,       /* CRC Error */
        Long            = 0x0008,       /* Long Packet */
        Runt            = 0x0010,       /* Runt Packet Received */
        Ise             = 0x0020,       /* Invalid Symbol Error */
        Bar             = 0x2000,       /* Broadcast Address Received */
        Pam             = 0x4000,       /* Physical Address Matched */
        Mar             = 0x8000,       /* Multicast Address Received */
};

enum {                                  /* Media Status Register */
        Rxpf            = 0x01,         /* Pause Flag */
        Txpf            = 0x02,         /* Pause Flag */
        Linkb           = 0x04,         /* Inverse of Link Status */
        Speed10         = 0x08,         /* 10Mbps */
        Auxstatus       = 0x10,         /* Aux. Power Present Status */
        Rxfce           = 0x40,         /* Receive Flow Control Enable */
        Txfce           = 0x80,         /* Transmit Flow Control Enable */
};

typedef struct Td Td;
struct Td {                     /* Soft Transmit Descriptor */
        int     tsd;
        int     tsad;
        uchar*  data;
        Block*  bp;
};

enum {                                  /* Tsd0 */
        SizeSHIFT       = 0,            /* Descriptor Size */
        SizeMASK        = 0x00001FFF,
        Own             = 0x00002000,
        Tun             = 0x00004000,   /* Transmit FIFO Underrun */
        Tcok            = 0x00008000,   /* Transmit COmpleted OK */
        EtxthSHIFT      = 16,           /* Early Tx Threshold */
        EtxthMASK       = 0x001F0000,
        NccSHIFT        = 24,           /* Number of Collisions Count */
        NccMASK         = 0x0F000000,
        Cdh             = 0x10000000,   /* CD Heartbeat */
        Owc             = 0x20000000,   /* Out of Window Collision */
        Tabt            = 0x40000000,   /* Transmit Abort */
        Crs             = 0x80000000,   /* Carrier Sense Lost */
};

enum {
        Rblen           = Rblen64K,     /* Receive Buffer Length */
        Ntd             = 4,            /* Number of Transmit Descriptors */
        Tdbsz           = ROUNDUP(sizeof(Etherpkt), 4),
};

typedef struct Ctlr Ctlr;
typedef struct Ctlr {
        int     port;
        Pcidev* pcidev;
        Ctlr*   next;
        int     active;
        int     id;

        QLock   alock;                  /* attach */
        Lock    ilock;                  /* init */
        void*   alloc;                  /* base of per-Ctlr allocated data */

        int     pcie;                   /* flag: pci-express device? */

        uvlong  mchash;                 /* multicast hash */

        int     rcr;                    /* receive configuration register */
        uchar*  rbstart;                /* receive buffer */
        int     rblen;                  /* receive buffer length */
        int     ierrs;                  /* receive errors */

        Lock    tlock;                  /* transmit */
        Td      td[Ntd];
        int     ntd;                    /* descriptors active */
        int     tdh;                    /* host index into td */
        int     tdi;                    /* interface index into td */
        int     etxth;                  /* early transmit threshold */
        int     taligned;               /* packet required no alignment */
        int     tunaligned;             /* packet required alignment */

        int     dis;                    /* disconnect counter */
        int     fcsc;                   /* false carrier sense counter */
        int     rec;                    /* RX_ER counter */
        uint    mcast;
} Ctlr;

static Ctlr* ctlrhead;
static Ctlr* ctlrtail;

#define csr8r(c, r)     (inb((c)->port+(r)))
#define csr16r(c, r)    (ins((c)->port+(r)))
#define csr32r(c, r)    (inl((c)->port+(r)))
#define csr8w(c, r, b)  (outb((c)->port+(r), (int)(b)))
#define csr16w(c, r, w) (outs((c)->port+(r), (ushort)(w)))
#define csr32w(c, r, l) (outl((c)->port+(r), (ulong)(l)))

static void
rtl8139promiscuous(void* arg, int on)
{
        Ether *edev;
        Ctlr * ctlr;

        edev = arg;
        ctlr = edev->ctlr;
        ilock(&ctlr->ilock);

        if(on)
                ctlr->rcr |= Aap;
        else
                ctlr->rcr &= ~Aap;
        csr32w(ctlr, Rcr, ctlr->rcr);
        iunlock(&ctlr->ilock);
}

enum {
        /* everyone else uses 0x04c11db7, but they both produce the same crc */
        Etherpolybe = 0x04c11db6,
        Bytemask = (1<<8) - 1,
};

static ulong
ethercrcbe(uchar *addr, long len)
{
        int i, j;
        ulong c, crc, carry;

        crc = ~0UL;
        for (i = 0; i < len; i++) {
                c = addr[i];
                for (j = 0; j < 8; j++) {
                        carry = ((crc & (1UL << 31))? 1: 0) ^ (c & 1);
                        crc <<= 1;
                        c >>= 1;
                        if (carry)
                                crc = (crc ^ Etherpolybe) | carry;
                }
        }
        return crc;
}

static ulong
swabl(ulong l)
{
        return l>>24 | (l>>8) & (Bytemask<<8) |
                (l<<8) & (Bytemask<<16) | l<<24;
}

static void
rtl8139multicast(void* ether, uchar *eaddr, int add)
{
        Ether *edev;
        Ctlr *ctlr;

        if (!add)
                return; /* ok to keep receiving on old mcast addrs */

        edev = ether;
        ctlr = edev->ctlr;
        ilock(&ctlr->ilock);

        ctlr->mchash |= 1ULL << (ethercrcbe(eaddr, Eaddrlen) >> 26);

        ctlr->rcr |= Am;
        csr32w(ctlr, Rcr, ctlr->rcr);

        /* pci-e variants reverse the order of the hash byte registers */
        if (0 && ctlr->pcie) {
                csr32w(ctlr, Mar0,   swabl(ctlr->mchash>>32));
                csr32w(ctlr, Mar0+4, swabl(ctlr->mchash));
        } else {
                csr32w(ctlr, Mar0,   ctlr->mchash);
                csr32w(ctlr, Mar0+4, ctlr->mchash>>32);
        }

        iunlock(&ctlr->ilock);
}

static long
rtl8139ifstat(Ether* edev, void* a, long n, ulong offset)
{
        int l;
        char *p;
        Ctlr *ctlr;

        ctlr = edev->ctlr;
        p = malloc(READSTR);
        if(p == nil)
                error(Enomem);
        l = snprint(p, READSTR, "rcr %#8.8ux\n", ctlr->rcr);
        l += snprint(p+l, READSTR-l, "multicast %ud\n", ctlr->mcast);
        l += snprint(p+l, READSTR-l, "ierrs %d\n", ctlr->ierrs);
        l += snprint(p+l, READSTR-l, "etxth %d\n", ctlr->etxth);
        l += snprint(p+l, READSTR-l, "taligned %d\n", ctlr->taligned);
        l += snprint(p+l, READSTR-l, "tunaligned %d\n", ctlr->tunaligned);
        ctlr->dis += csr16r(ctlr, Dis);
        l += snprint(p+l, READSTR-l, "dis %d\n", ctlr->dis);
        ctlr->fcsc += csr16r(ctlr, Fcsc);
        l += snprint(p+l, READSTR-l, "fcscnt %d\n", ctlr->fcsc);
        ctlr->rec += csr16r(ctlr, Rec);
        l += snprint(p+l, READSTR-l, "rec %d\n", ctlr->rec);

        l += snprint(p+l, READSTR-l, "Tcr %#8.8lux\n", csr32r(ctlr, Tcr));
        l += snprint(p+l, READSTR-l, "Config0 %#2.2ux\n", csr8r(ctlr, Config0));
        l += snprint(p+l, READSTR-l, "Config1 %#2.2ux\n", csr8r(ctlr, Config1));
        l += snprint(p+l, READSTR-l, "Msr %#2.2ux\n", csr8r(ctlr, Msr));
        l += snprint(p+l, READSTR-l, "Config3 %#2.2ux\n", csr8r(ctlr, Config3));
        l += snprint(p+l, READSTR-l, "Config4 %#2.2ux\n", csr8r(ctlr, Config4));

        l += snprint(p+l, READSTR-l, "Bmcr %#4.4ux\n", csr16r(ctlr, Bmcr));
        l += snprint(p+l, READSTR-l, "Bmsr %#4.4ux\n", csr16r(ctlr, Bmsr));
        l += snprint(p+l, READSTR-l, "Anar %#4.4ux\n", csr16r(ctlr, Anar));
        l += snprint(p+l, READSTR-l, "Anlpar %#4.4ux\n", csr16r(ctlr, Anlpar));
        l += snprint(p+l, READSTR-l, "Aner %#4.4ux\n", csr16r(ctlr, Aner));
        l += snprint(p+l, READSTR-l, "Nwaytr %#4.4ux\n", csr16r(ctlr, Nwaytr));
        snprint(p+l, READSTR-l, "Cscr %#4.4ux\n", csr16r(ctlr, Cscr));
        n = readstr(offset, a, n, p);
        free(p);

        return n;
}

static int
rtl8139reset(Ctlr* ctlr)
{
        int timeo;

        /* stop interrupts */
        csr16w(ctlr, Imr, 0);
        csr16w(ctlr, Isr, ~0);
        csr32w(ctlr, TimerInt, 0);

        /*
         * Soft reset the controller.
         */
        csr8w(ctlr, Cr, Rst);
        for(timeo = 0; timeo < 1000; timeo++){
                if(!(csr8r(ctlr, Cr) & Rst))
                        return 0;
                delay(1);
        }

        return -1;
}

static void
rtl8139halt(Ctlr* ctlr)
{
        int i;

        csr8w(ctlr, Cr, 0);
        csr16w(ctlr, Imr, 0);
        csr16w(ctlr, Isr, ~0);
        csr32w(ctlr, TimerInt, 0);

        for(i = 0; i < Ntd; i++){
                if(ctlr->td[i].bp == nil)
                        continue;
                freeb(ctlr->td[i].bp);
                ctlr->td[i].bp = nil;
        }
}

static void
rtl8139shutdown(Ether *edev)
{
        Ctlr *ctlr;

        ctlr = edev->ctlr;
        ilock(&ctlr->ilock);
        rtl8139halt(ctlr);
        rtl8139reset(ctlr);
        iunlock(&ctlr->ilock);
}

static void
rtl8139init(Ether* edev)
{
        int i;
        ulong r;
        Ctlr *ctlr;
        uchar *alloc;

        ctlr = edev->ctlr;
        ilock(&ctlr->ilock);

        rtl8139halt(ctlr);

        /*
         * MAC Address.
         */
        r = (edev->ea[3]<<24)|(edev->ea[2]<<16)|(edev->ea[1]<<8)|edev->ea[0];
        csr32w(ctlr, Idr0, r);
        r = (edev->ea[5]<<8)|edev->ea[4];
        csr32w(ctlr, Idr0+4, r);

        /*
         * Receiver
         */
        alloc = (uchar*)ROUNDUP((ulong)ctlr->alloc, 32);
        ctlr->rbstart = alloc;
        alloc += ctlr->rblen+16;
        memset(ctlr->rbstart, 0, ctlr->rblen+16);
        csr32w(ctlr, Rbstart, PCIWADDR(ctlr->rbstart));
        ctlr->rcr = Rxfth256|Rblen|Mrxdmaunlimited|Ab|Am|Apm;

        /*
         * Transmitter.
         */
        for(i = 0; i < Ntd; i++){
                ctlr->td[i].tsd = Tsd0+i*4;
                ctlr->td[i].tsad = Tsad0+i*4;
                ctlr->td[i].data = alloc;
                alloc += Tdbsz;
                ctlr->td[i].bp = nil;
        }
        ctlr->ntd = ctlr->tdh = ctlr->tdi = 0;
        ctlr->etxth = 128/32;

        /*
         * Enable receiver/transmitter.
         * Need to enable before writing the Rcr or it won't take.
         */
        csr8w(ctlr, Cr, Te|Re);
        csr32w(ctlr, Tcr, Mtxdma2048);
        csr32w(ctlr, Rcr, ctlr->rcr);
        csr32w(ctlr, Mar0,   0);
        csr32w(ctlr, Mar0+4, 0);
        ctlr->mchash = 0;

        /*
         * Interrupts.
         */
        csr32w(ctlr, TimerInt, 0);
        csr16w(ctlr, Imr, Serr|Timerbit|Fovw|PunLc|Rxovw|Ter|Tok|Rer|Rok);
        csr32w(ctlr, Mpc, 0);

        iunlock(&ctlr->ilock);
}

static void
rtl8139attach(Ether* edev)
{
        Ctlr *ctlr;

        if(edev == nil) {
                print("rtl8139attach: nil edev\n");
                return;
        }
        ctlr = edev->ctlr;
        if(ctlr == nil) {
                print("rtl8139attach: nil ctlr for Ether %#p\n", edev);
                return;
        }
        qlock(&ctlr->alock);
        if(ctlr->alloc == nil){
                ctlr->rblen = 1<<((Rblen>>RblenSHIFT)+13);
                ctlr->alloc = malloc(ctlr->rblen+16 + Ntd*Tdbsz + 32);
                if(ctlr->alloc == nil) {
                        qunlock(&ctlr->alock);
                        error(Enomem);
                }
                rtl8139init(edev);
        }
        qunlock(&ctlr->alock);
}

static void
rtl8139txstart(Ether* edev)
{
        Td *td;
        int size;
        Block *bp;
        Ctlr *ctlr;

        ctlr = edev->ctlr;
        while(ctlr->ntd < Ntd){
                bp = qget(edev->oq);
                if(bp == nil)
                        break;
                size = BLEN(bp);

                td = &ctlr->td[ctlr->tdh];
                if(((int)bp->rp) & 0x03){
                        memmove(td->data, bp->rp, size);
                        freeb(bp);
                        csr32w(ctlr, td->tsad, PCIWADDR(td->data));
                        ctlr->tunaligned++;
                }
                else{
                        td->bp = bp;
                        csr32w(ctlr, td->tsad, PCIWADDR(bp->rp));
                        ctlr->taligned++;
                }
                csr32w(ctlr, td->tsd, (ctlr->etxth<<EtxthSHIFT)|size);

                ctlr->ntd++;
                ctlr->tdh = NEXT(ctlr->tdh, Ntd);
        }
}

static void
rtl8139transmit(Ether* edev)
{
        Ctlr *ctlr;

        ctlr = edev->ctlr;
        ilock(&ctlr->tlock);
        rtl8139txstart(edev);
        iunlock(&ctlr->tlock);
}

static void
rtl8139receive(Ether* edev)
{
        Block *bp;
        Ctlr *ctlr;
        ushort capr;
        uchar cr, *p;
        int l, length, status;

        ctlr = edev->ctlr;

        /*
         * Capr is where the host is reading from,
         * Cbr is where the NIC is currently writing.
         */
        if(ctlr->rblen == 0)
                return;         /* not attached yet (shouldn't happen) */
        capr = (csr16r(ctlr, Capr)+16) % ctlr->rblen;
        while(!(csr8r(ctlr, Cr) & Bufe)){
                p = ctlr->rbstart+capr;

                /*
                 * Apparently the packet length may be 0xFFF0 if
                 * the NIC is still copying the packet into memory.
                 */
                length = (*(p+3)<<8)|*(p+2);
                if(length == 0xFFF0)
                        break;
                status = (*(p+1)<<8)|*p;

                if(!(status & Rcok)){
                        if(status & (Ise|Fae))
                                edev->frames++;
                        if(status & Crc)
                                edev->crcs++;
                        if(status & (Runt|Long))
                                edev->buffs++;

                        /*
                         * Reset the receiver.
                         * Also may have to restore the multicast list
                         * here too if it ever gets used.
                         */
                        cr = csr8r(ctlr, Cr);
                        csr8w(ctlr, Cr, cr & ~Re);
                        csr32w(ctlr, Rbstart, PCIWADDR(ctlr->rbstart));
                        csr8w(ctlr, Cr, cr);
                        csr32w(ctlr, Rcr, ctlr->rcr);

                        continue;
                }

                /*
                 * Receive Completed OK.
                 * Very simplistic; there are ways this could be done
                 * without copying, but the juice probably isn't worth
                 * the squeeze.
                 * The packet length includes a 4 byte CRC on the end.
                 */
                capr = (capr+4) % ctlr->rblen;
                p = ctlr->rbstart+capr;
                capr = (capr+length) % ctlr->rblen;
                if(status & Mar)
                        ctlr->mcast++;

                if((bp = iallocb(length)) != nil){
                        if(p+length >= ctlr->rbstart+ctlr->rblen){
                                l = ctlr->rbstart+ctlr->rblen - p;
                                memmove(bp->wp, p, l);
                                bp->wp += l;
                                length -= l;
                                p = ctlr->rbstart;
                        }
                        if(length > 0){
                                memmove(bp->wp, p, length);
                                bp->wp += length;
                        }
                        bp->wp -= 4;
                        etheriq(edev, bp, 1);
                }

                capr = ROUNDUP(capr, 4);
                csr16w(ctlr, Capr, capr-16);
        }
}

static void
rtl8139interrupt(Ureg*, void* arg)
{
        Td *td;
        Ctlr *ctlr;
        Ether *edev;
        int isr, msr, tsd;

        edev = arg;
        ctlr = edev->ctlr;
        if(ctlr == nil) {       /* not attached yet? (shouldn't happen) */
                print("rtl8139interrupt: interrupt for unattached Ether %#p\n",
                        edev);
                return;
        }

        while((isr = csr16r(ctlr, Isr)) != 0){
                csr16w(ctlr, Isr, isr);
                if(ctlr->alloc == nil) {
                        print("rtl8139interrupt: interrupt for unattached Ctlr "
                                "%#p port %#p\n", ctlr, (void *)ctlr->port);
                        return; /* not attached yet (shouldn't happen) */
                }
                if(isr & (Fovw|PunLc|Rxovw|Rer|Rok)){
                        rtl8139receive(edev);
                        if(!(isr & Rok))
                                ctlr->ierrs++;
                        isr &= ~(Fovw|Rxovw|Rer|Rok);
                }

                if(isr & (Ter|Tok)){
                        ilock(&ctlr->tlock);
                        while(ctlr->ntd){
                                td = &ctlr->td[ctlr->tdi];
                                tsd = csr32r(ctlr, td->tsd);
                                if(!(tsd & (Tabt|Tun|Tcok)))
                                        break;

                                if(!(tsd & Tcok)){
                                        if(tsd & Tun){
                                                if(ctlr->etxth < ETHERMAXTU/32)
                                                        ctlr->etxth++;
                                        }
                                        edev->oerrs++;
                                }

                                if(td->bp != nil){
                                        freeb(td->bp);
                                        td->bp = nil;
                                }

                                ctlr->ntd--;
                                ctlr->tdi = NEXT(ctlr->tdi, Ntd);
                        }
                        rtl8139txstart(edev);
                        iunlock(&ctlr->tlock);
                        isr &= ~(Ter|Tok);
                }

                if(isr & PunLc){
                        /*
                         * Maybe the link changed - do we care very much?
                         */
                        msr = csr8r(ctlr, Msr);
                        if(!(msr & Linkb)){
                                if(!(msr & Speed10) && edev->mbps != 100){
                                        edev->mbps = 100;
                                        qsetlimit(edev->oq, 256*1024);
                                }
                                else if((msr & Speed10) && edev->mbps != 10){
                                        edev->mbps = 10;
                                        qsetlimit(edev->oq, 65*1024);
                                }
                        }
                        isr &= ~(Clc|PunLc);
                }

                /*
                 * Only Serr|Timerbit should be left by now.
                 * Should anything be done to tidy up? TimerInt isn't
                 * used so that can be cleared. A PCI bus error is indicated
                 * by Serr, that's pretty serious; is there anyhing to do
                 * other than try to reinitialise the chip?
                 */
                if((isr & (Serr|Timerbit)) != 0){
                        iprint("rtl8139interrupt: imr %#4.4ux isr %#4.4ux\n",
                                csr16r(ctlr, Imr), isr);
                        if(isr & Timerbit)
                                csr32w(ctlr, TimerInt, 0);
                        if(isr & Serr)
                                rtl8139init(edev);
                }
        }
}

static Ctlr*
rtl8139match(Ether* edev, int id)
{
        Pcidev *p;
        Ctlr *ctlr;
        int i, port;

        /*
         * Any adapter matches if no edev->port is supplied,
         * otherwise the ports must match.
         */
        for(ctlr = ctlrhead; ctlr != nil; ctlr = ctlr->next){
                if(ctlr->active)
                        continue;
                p = ctlr->pcidev;
                if(((p->did<<16)|p->vid) != id)
                        continue;
                port = p->mem[0].bar & ~0x01;
                if(edev->port != 0 && edev->port != port)
                        continue;

                if(ioalloc(port, p->mem[0].size, 0, "rtl8139") < 0){
                        print("rtl8139: port %#ux in use\n", port);
                        continue;
                }

                if(pcigetpms(p) > 0){
                        pcisetpms(p, 0);
        
                        for(i = 0; i < 6; i++)
                                pcicfgw32(p, PciBAR0+i*4, p->mem[i].bar);
                        pcicfgw8(p, PciINTL, p->intl);
                        pcicfgw8(p, PciLTR, p->ltr);
                        pcicfgw8(p, PciCLS, p->cls);
                        pcicfgw16(p, PciPCR, p->pcr);
                }

                ctlr->port = port;
                if(rtl8139reset(ctlr)) {
                        iofree(port);
                        continue;
                }
                pcisetbme(p);

                ctlr->active = 1;
                return ctlr;
        }
        return nil;
}

static struct {
        char*   name;
        int     id;
} rtl8139pci[] = {
        { "rtl8139",    (0x8139<<16)|0x10EC, }, /* generic */
        { "smc1211",    (0x1211<<16)|0x1113, }, /* SMC EZ-Card */
        { "dfe-538tx",  (0x1300<<16)|0x1186, }, /* D-Link DFE-538TX */
        { "dfe-560txd", (0x1340<<16)|0x1186, }, /* D-Link DFE-560TXD */
        { nil },
};

static int
rtl8139pnp(Ether* edev)
{
        int i, id;
        Pcidev *p;
        Ctlr *ctlr;
        uchar ea[Eaddrlen];

        /*
         * Make a list of all ethernet controllers
         * if not already done.
         */
        if(ctlrhead == nil){
                p = nil;
                while(p = pcimatch(p, 0, 0)){
                        if(p->ccrb != 0x02 || p->ccru != 0)
                                continue;
                        ctlr = malloc(sizeof(Ctlr));
                        if(ctlr == nil)
                                error(Enomem);
                        ctlr->pcidev = p;
                        ctlr->id = (p->did<<16)|p->vid;

                        if(ctlrhead != nil)
                                ctlrtail->next = ctlr;
                        else
                                ctlrhead = ctlr;
                        ctlrtail = ctlr;
                }
        }

        /*
         * Is it an RTL8139 under a different name?
         * Normally a search is made through all the found controllers
         * for one which matches any of the known vid+did pairs.
         * If a vid+did pair is specified a search is made for that
         * specific controller only.
         */
        id = 0;
        for(i = 0; i < edev->nopt; i++){
                if(cistrncmp(edev->opt[i], "id=", 3) == 0)
                        id = strtol(&edev->opt[i][3], nil, 0);
        }

        ctlr = nil;
        if(id != 0)
                ctlr = rtl8139match(edev, id);
        else for(i = 0; rtl8139pci[i].name; i++){
                if((ctlr = rtl8139match(edev, rtl8139pci[i].id)) != nil)
                        break;
        }
        if(ctlr == nil)
                return -1;

        edev->ctlr = ctlr;
        edev->port = ctlr->port;
        edev->irq = ctlr->pcidev->intl;
        edev->tbdf = ctlr->pcidev->tbdf;

        /*
         * Check if the adapter's station address is to be overridden.
         * If not, read it from the device and set in edev->ea.
         */
        memset(ea, 0, Eaddrlen);
        if(memcmp(ea, edev->ea, Eaddrlen) == 0){
                i = csr32r(ctlr, Idr0);
                edev->ea[0] = i;
                edev->ea[1] = i>>8;
                edev->ea[2] = i>>16;
                edev->ea[3] = i>>24;
                i = csr32r(ctlr, Idr0+4);
                edev->ea[4] = i;
                edev->ea[5] = i>>8;
        }

        edev->arg = edev;
        edev->attach = rtl8139attach;
        edev->transmit = rtl8139transmit;
        edev->interrupt = rtl8139interrupt;
        edev->ifstat = rtl8139ifstat;

        edev->promiscuous = rtl8139promiscuous;
        edev->multicast = rtl8139multicast;
        edev->shutdown = rtl8139shutdown;

        /*
         * This should be much more dynamic but will do for now.
         */
        if((csr8r(ctlr, Msr) & (Speed10|Linkb)) == 0)
                edev->mbps = 100;

        return 0;
}

void
ether8139link(void)
{
        addethercard("rtl8139", rtl8139pnp);
}