/*
 * Etherboot -  BOOTP/TFTP Bootstrap Program
 *
 * w89c840.c -- This file implements the winbond-840 driver for etherboot.
 *
 */

/*
 * Adapted by Igor V. Kovalenko
 *  -- <garrison@mail.ru>
 *   OR
 *  -- <iko@crec.mipt.ru>
 * Initial adaptaion stage, including testing, completed 23 August 2000.
 */

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2, or (at
 * your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 *              date       version  by   what
 *  Written:    Aug 20 2000  V0.10  iko  Initial revision.
 * changes:     Aug 22 2000  V0.90  iko  Works!
 *              Aug 23 2000  V0.91  iko  Cleanup, posted to etherboot
 *                                       maintainer.
 *              Aug 26 2000  V0.92  iko  Fixed Rx ring handling.
 *                                       First Linux Kernel (TM)
 *                                       successfully loaded using
 *                                       this driver.
 *              Jan 07 2001  V0.93  iko  Transmitter timeouts are handled
 *                                       using timer2 routines. Proposed
 *                                       by Ken Yap to eliminate CPU speed
 *                                       dependency.
 *
 * This is the etherboot driver for cards based on Winbond W89c840F chip.
 *
 * It was written from skeleton source, with Donald Becker's winbond-840.c
 * kernel driver as a guideline. Mostly the w89c840 related definitions
 * and the lower level routines have been cut-and-pasted into this source.
 *
 * Frankly speaking, about 90% of the code was obtained using cut'n'paste
 * sequence :) while the remainder appeared while brainstorming
 * Linux Kernel 2.4.0-testX source code. Thanks, Donald and Linus!
 *
 * There was a demand for using this card in a rather large
 * remote boot environment at MSKP OVTI Lab of
 * Moscow Institute for Physics and Technology (MIPT) -- http://www.mipt.ru/
 * so you may count that for motivation.
 *
 */

/*
 * If you want to see debugging output then define W89C840_DEBUG
 */

/*
#define W89C840_DEBUG
*/

/*
 * Keep using IO_OPS for Etherboot driver!
 */
#define USE_IO_OPS

#include "etherboot.h"
#include "nic.h"
#include "pci.h"
#include "cards.h"
#include "timer.h"

static const char *w89c840_version = "diver Version 0.92 - August 27, 2000";

typedef unsigned char  u8;
typedef   signed char  s8;
typedef unsigned short u16;
typedef   signed short s16;
typedef unsigned int   u32;
typedef   signed int   s32;

/* Linux support functions */
#define virt_to_bus(x) ((unsigned long)x)
#define bus_to_virt(x) ((void *)x)

#define virt_to_le32desc(addr)  virt_to_bus(addr)
#define le32desc_to_virt(addr)  bus_to_virt(addr)

/*
#define cpu_to_le32(val) (val)
#define le32_to_cpu(val) (val)
*/

/* Operational parameters that are set at compile time. */

/* Keep the ring sizes a power of two for compile efficiency.
   The compiler will convert <unsigned>'%'<2^N> into a bit mask.
   Making the Tx ring too large decreases the effectiveness of channel
   bonding and packet priority.
   There are no ill effects from too-large receive rings. */
#define TX_RING_SIZE    2

#define RX_RING_SIZE    2

/* The presumed FIFO size for working around the Tx-FIFO-overflow bug.
   To avoid overflowing we don't queue again until we have room for a
   full-size packet.
 */
#define TX_FIFO_SIZE (2048)
#define TX_BUG_FIFO_LIMIT (TX_FIFO_SIZE-1514-16)

/* Operational parameters that usually are not changed. */
/* Time in jiffies before concluding the transmitter is hung. */
#define TX_TIMEOUT  (10*TICKS_PER_MS)

#define PKT_BUF_SZ  1536  /* Size of each temporary Rx buffer.*/

/*
 * Used to be this much CPU loops on Celeron@400 (?),
 * now using real timer and TX_TIMEOUT!
 * #define TX_LOOP_COUNT 10000000
 */

#if !defined(__OPTIMIZE__)
#warning  You must compile this file with the correct options!
#warning  See the last lines of the source file.
#error You must compile this driver with "-O".
#endif

enum chip_capability_flags {CanHaveMII=1, HasBrokenTx=2};

#ifdef USE_IO_OPS
#define W840_FLAGS (PCI_USES_IO | PCI_ADDR0 | PCI_USES_MASTER)
#else
#define W840_FLAGS (PCI_USES_MEM | PCI_ADDR1 | PCI_USES_MASTER)
#endif

static u32 driver_flags = CanHaveMII | HasBrokenTx;

/* This driver was written to use PCI memory space, however some x86 systems
   work only with I/O space accesses.  Pass -DUSE_IO_OPS to use PCI I/O space
   accesses instead of memory space. */

#ifdef USE_IO_OPS
#undef readb
#undef readw
#undef readl
#undef writeb
#undef writew
#undef writel
#define readb inb
#define readw inw
#define readl inl
#define writeb outb
#define writew outw
#define writel outl
#endif

/* Offsets to the Command and Status Registers, "CSRs".
   While similar to the Tulip, these registers are longword aligned.
   Note: It's not useful to define symbolic names for every register bit in
   the device.  The name can only partially document the semantics and make
   the driver longer and more difficult to read.
*/
enum w840_offsets {
    PCIBusCfg=0x00, TxStartDemand=0x04, RxStartDemand=0x08,
    RxRingPtr=0x0C, TxRingPtr=0x10,
    IntrStatus=0x14, NetworkConfig=0x18, IntrEnable=0x1C,
    RxMissed=0x20, EECtrl=0x24, MIICtrl=0x24, BootRom=0x28, GPTimer=0x2C,
    CurRxDescAddr=0x30, CurRxBufAddr=0x34,            /* Debug use */
    MulticastFilter0=0x38, MulticastFilter1=0x3C, StationAddr=0x40,
    CurTxDescAddr=0x4C, CurTxBufAddr=0x50,
};

/* Bits in the interrupt status/enable registers. */
/* The bits in the Intr Status/Enable registers, mostly interrupt sources. */
enum intr_status_bits {
    NormalIntr=0x10000, AbnormalIntr=0x8000,
    IntrPCIErr=0x2000, TimerInt=0x800,
    IntrRxDied=0x100, RxNoBuf=0x80, IntrRxDone=0x40,
    TxFIFOUnderflow=0x20, RxErrIntr=0x10,
    TxIdle=0x04, IntrTxStopped=0x02, IntrTxDone=0x01,
};

/* Bits in the NetworkConfig register. */
enum rx_mode_bits {
    AcceptErr=0x80, AcceptRunt=0x40,
    AcceptBroadcast=0x20, AcceptMulticast=0x10,
    AcceptAllPhys=0x08, AcceptMyPhys=0x02,
};

enum mii_reg_bits {
    MDIO_ShiftClk=0x10000, MDIO_DataIn=0x80000, MDIO_DataOut=0x20000,
    MDIO_EnbOutput=0x40000, MDIO_EnbIn = 0x00000,
};

/* The Tulip Rx and Tx buffer descriptors. */
struct w840_rx_desc {
    s32 status;
    s32 length;
    u32 buffer1;
    u32 next_desc;
};

struct w840_tx_desc {
    s32 status;
    s32 length;
    u32 buffer1, buffer2;                /* We use only buffer 1.  */
};

/* Bits in network_desc.status */
enum desc_status_bits {
    DescOwn=0x80000000, DescEndRing=0x02000000, DescUseLink=0x01000000,
    DescWholePkt=0x60000000, DescStartPkt=0x20000000, DescEndPkt=0x40000000,
    DescIntr=0x80000000,
};
#define PRIV_ALIGN    15     /* Required alignment mask */
#define PRIV_ALIGN_BYTES 32

static struct winbond_private
{
    /* Descriptor rings first for alignment. */
    struct w840_rx_desc rx_ring[RX_RING_SIZE];
    struct w840_tx_desc tx_ring[TX_RING_SIZE];
    struct net_device *next_module;        /* Link for devices of this type. */
    void *priv_addr;                    /* Unaligned address for kfree */
    const char *product_name;
    /* Frequently used values: keep some adjacent for cache effect. */
    int chip_id, drv_flags;
    struct pci_dev *pci_dev;
    int csr6;
    struct w840_rx_desc *rx_head_desc;
    unsigned int cur_rx, dirty_rx;        /* Producer/consumer ring indices */
    unsigned int rx_buf_sz;                /* Based on MTU+slack. */
    unsigned int cur_tx, dirty_tx;
    int tx_q_bytes;
    unsigned int tx_full:1;                /* The Tx queue is full. */
    /* These values are keep track of the transceiver/media in use. */
    unsigned int full_duplex:1;            /* Full-duplex operation requested. */
    unsigned int duplex_lock:1;
    unsigned int medialock:1;            /* Do not sense media. */
    unsigned int default_port:4;        /* Last dev->if_port value. */
    /* MII transceiver section. */
    int mii_cnt;                        /* MII device addresses. */
    u16 advertising;                    /* NWay media advertisement */
    unsigned char phys[2];                /* MII device addresses. */
} w840private __attribute__ ((aligned (PRIV_ALIGN_BYTES)));

/* NIC specific static variables go here */

static int ioaddr;
static unsigned short eeprom [0x40];

#ifdef    USE_LOWMEM_BUFFER
#define rx_packet ((char *)0x10000 - PKT_BUF_SZ * RX_RING_SIZE)
#define tx_packet ((char *)0x10000 - PKT_BUF_SZ * RX_RING_SIZE - PKT_BUF_SZ * TX_RING_SIZE)
#else
static char        rx_packet[PKT_BUF_SZ * RX_RING_SIZE];
static char        tx_packet[PKT_BUF_SZ * TX_RING_SIZE];
#endif

static int  eeprom_read(long ioaddr, int location);
static int  mdio_read(int base_address, int phy_id, int location);
static void mdio_write(int base_address, int phy_id, int location, int value);

static void check_duplex(void);
static void set_rx_mode(void);
static void init_ring(void);

/*
static void wait_long_time(void)
{
    printf("Paused - please read output above this line\n");
    sleep(3);
}
*/

#if defined W89C840_DEBUG
static void decode_interrupt(u32 intr_status)
{
    printf("Interrupt status: ");

#define TRACE_INTR(_intr_) \
    if (intr_status & (_intr_)) { printf (" " #_intr_); }

    TRACE_INTR(NormalIntr);
    TRACE_INTR(AbnormalIntr);
    TRACE_INTR(IntrPCIErr);
    TRACE_INTR(TimerInt);
    TRACE_INTR(IntrRxDied);
    TRACE_INTR(RxNoBuf);
    TRACE_INTR(IntrRxDone);
    TRACE_INTR(TxFIFOUnderflow);
    TRACE_INTR(RxErrIntr);
    TRACE_INTR(TxIdle);
    TRACE_INTR(IntrTxStopped);
    TRACE_INTR(IntrTxDone);

    printf("\n");
    /*sleep(1);*/
}
#endif

/**************************************************************************
w89c840_reset - Reset adapter
***************************************************************************/
static void w89c840_reset(struct nic *nic)
{
    int i;

    /* Reset the chip to erase previous misconfiguration.
       No hold time required! */
    writel(0x00000001, ioaddr + PCIBusCfg);

    init_ring();

    writel(virt_to_bus(w840private.rx_ring), ioaddr + RxRingPtr);
    writel(virt_to_bus(w840private.tx_ring), ioaddr + TxRingPtr);

    for (i = 0; i < ETH_ALEN; i++)
        writeb(nic->node_addr[i], ioaddr + StationAddr + i);

    /* Initialize other registers. */
    /* Configure the PCI bus bursts and FIFO thresholds.
       486: Set 8 longword cache alignment, 8 longword burst.
       586: Set 16 longword cache alignment, no burst limit.
       Cache alignment bits 15:14         Burst length 13:8
        0000    <not allowed>         0000 align to cache    0800 8 longwords
        4000    8  longwords        0100 1 longword        1000 16 longwords
        8000    16 longwords        0200 2 longwords    2000 32 longwords
        C000    32  longwords        0400 4 longwords
       Wait the specified 50 PCI cycles after a reset by initializing
       Tx and Rx queues and the address filter list. */

    writel(0xE010, ioaddr + PCIBusCfg);

    writel(0, ioaddr + RxStartDemand);
    w840private.csr6 = 0x20022002;
    check_duplex();
    set_rx_mode();

    /* Clear and Enable interrupts by setting the interrupt mask. */
    writel(0x1A0F5, ioaddr + IntrStatus);
    writel(0x1A0F5, ioaddr + IntrEnable);

#if defined(W89C840_DEBUG)
    printf("winbond-840 : Done reset.\n");
#endif
}

static void handle_intr(u32 intr_stat)
{
    if ((intr_stat & (NormalIntr|AbnormalIntr)) == 0) {
        /* we are polling, do not return now */
        /*return 0;*/
    } else {
        /* Acknowledge all of the current interrupt sources ASAP. */
        writel(intr_stat & 0x001ffff, ioaddr + IntrStatus);
    }

    if (intr_stat & AbnormalIntr) {
        /* There was an abnormal interrupt */
        printf("\n-=- Abnormal interrupt.\n");

#if defined (W89C840_DEBUG)
        decode_interrupt(intr_stat);
#endif

        if (intr_stat & RxNoBuf) {
            /* There was an interrupt */
            printf("-=- <=> No receive buffers available.\n");
            writel(0, ioaddr + RxStartDemand);
        }
    }
}

/**************************************************************************
w89c840_poll - Wait for a frame
***************************************************************************/
static int w89c840_poll(struct nic *nic)
{
    /* return true if there's an ethernet packet ready to read */
    /* nic->packet should contain data on return */
    /* nic->packetlen should contain length of data */
    int packet_received = 0;

    u32 intr_status = readl(ioaddr + IntrStatus);
    /* handle_intr(intr_status); */ /* -- handled later */

    do {
        /* Code from netdev_rx(dev) */

        int entry = w840private.cur_rx % RX_RING_SIZE;

        struct w840_rx_desc *desc = w840private.rx_head_desc;
        s32 status = desc->status;

        if (status & DescOwn) {
            /* DescOwn bit is still set, we should wait for RX to complete */
            packet_received = 0;
            break;
        }

        if ((status & 0x38008300) != 0x0300) {
            if ((status & 0x38000300) != 0x0300) {
                /* Ingore earlier buffers. */
                if ((status & 0xffff) != 0x7fff) {
                    printf("winbond-840 : Oversized Ethernet frame spanned "
                           "multiple buffers, entry %d status %X !\n",
                           w840private.cur_rx, status);
                }
            } else if (status & 0x8000) {
                /* There was a fatal error. */
#if defined(W89C840_DEBUG)
                printf("winbond-840 : Receive error, Rx status %X :", status);
                if (status & 0x0890) {
                    printf(" RXLEN_ERROR");
                }
                if (status & 0x004C) {
                    printf(", FRAME_ERROR");
                }
                if (status & 0x0002) {
                    printf(", CRC_ERROR");
                }
                printf("\n");
#endif

                /* Simpy do a reset now... */
                w89c840_reset(nic);

                packet_received = 0;
                break;
            }
        } else {
            /* Omit the four octet CRC from the length. */
            int pkt_len = ((status >> 16) & 0x7ff) - 4;

#if defined(W89C840_DEBUG)
            printf(" netdev_rx() normal Rx pkt ring %d length %d status %X\n", entry, pkt_len, status);
#endif

            nic->packetlen = pkt_len;

            /* Check if the packet is long enough to accept without copying
               to a minimally-sized skbuff. */

            memcpy(nic->packet, le32desc_to_virt(w840private.rx_ring[entry].buffer1), pkt_len);
            packet_received = 1;

            /* Release buffer to NIC */
            w840private.rx_ring[entry].status = DescOwn;

#if defined(W89C840_DEBUG)
            /* You will want this info for the initial debug. */
            printf("  Rx data %hhX:%hhX:%hhX:%hhX:%hhX:"
                   "%hhX %hhX:%hhX:%hhX:%hhX:%hhX:%hhX %hhX%hhX "
                   "%hhX.%hhX.%hhX.%hhX.\n",
                   nic->packet[0],  nic->packet[1],  nic->packet[2], nic->packet[3],
                   nic->packet[4],  nic->packet[5],  nic->packet[6], nic->packet[7],
                   nic->packet[8],  nic->packet[9],  nic->packet[10],
                   nic->packet[11], nic->packet[12], nic->packet[13],
                   nic->packet[14], nic->packet[15], nic->packet[16],
                   nic->packet[17]);
#endif

        }

        entry = (++w840private.cur_rx) % RX_RING_SIZE;
        w840private.rx_head_desc = &w840private.rx_ring[entry];
    } while (0);

    if (intr_status & (AbnormalIntr | TxFIFOUnderflow | IntrPCIErr |TimerInt | IntrTxStopped)) {
        handle_intr(intr_status);
    }

    return packet_received;
}

/**************************************************************************
w89c840_transmit - Transmit a frame
***************************************************************************/

static void w89c840_transmit(
    struct nic *nic,
    const char *d,            /* Destination */
    unsigned int t,            /* Type */
    unsigned int s,            /* size */
    const char *p)            /* Packet */
{
    /* send the packet to destination */
    unsigned entry;
    int transmit_status;

    /* Caution: the write order is important here, set the field
       with the "ownership" bits last. */

    /* Fill in our transmit buffer */
    entry = w840private.cur_tx % TX_RING_SIZE;

    memcpy (tx_packet, d, ETH_ALEN);    /* dst */
    memcpy (tx_packet + ETH_ALEN, nic->node_addr, ETH_ALEN);/* src */

    *((char *) tx_packet + 12) = t >> 8;    /* type */
    *((char *) tx_packet + 13) = t;

    memcpy (tx_packet + ETH_HLEN, p, s);
    s += ETH_HLEN;

    while (s < ETH_ZLEN)
    *((char *) tx_packet + ETH_HLEN + (s++)) = 0;

    w840private.tx_ring[entry].buffer1 = virt_to_le32desc(tx_packet);

    w840private.tx_ring[entry].length = (DescWholePkt | s);
    if (entry >= TX_RING_SIZE-1)         /* Wrap ring */
        w840private.tx_ring[entry].length |= (DescIntr | DescEndRing);
    w840private.tx_ring[entry].status = (DescOwn);
    w840private.cur_tx++;

    w840private.tx_q_bytes += s;
    writel(0, ioaddr + TxStartDemand);

    /* Work around horrible bug in the chip by marking the queue as full
       when we do not have FIFO room for a maximum sized packet. */

    if ((w840private.drv_flags & HasBrokenTx) && w840private.tx_q_bytes > TX_BUG_FIFO_LIMIT) {
        /* Actually this is left to help finding error tails later in debugging...
         * See Linux kernel driver in winbond-840.c for details.
         */
        w840private.tx_full = 1;
    }

#if defined(W89C840_DEBUG)
    printf("winbond-840 : Transmit frame # %d size %d queued in slot %d.\n", w840private.cur_tx, s, entry);
#endif

    /* Now wait for TX to complete. */
    transmit_status = w840private.tx_ring[entry].status;

    load_timer2(TX_TIMEOUT);

    {
        u32 intr_stat = 0;

        while (1) {

            intr_stat = readl(ioaddr + IntrStatus);
#if defined(W89C840_DEBUG)
            decode_interrupt(intr_stat);
#endif

            if (intr_stat & (NormalIntr | IntrTxDone)) {

                while ( (transmit_status & DescOwn) && timer2_running()) {

                    transmit_status = w840private.tx_ring[entry].status;
                }

                writel(intr_stat & 0x0001ffff, ioaddr + IntrStatus);
                break;
            }
        }
    }

    if ((transmit_status & DescOwn) == 0) {

#if defined(W89C840_DEBUG)
        printf("winbond-840 : transmission complete after %d wait loop iterations, status %X\n",
               TX_LOOP_COUNT - transmit_loop_counter, w840private.tx_ring[entry].status);
#endif

        return;
    }

    /* Transmit timed out... */

    printf("winbond-840 : transmission TIMEOUT : status %X\n", w840private.tx_ring[entry].status);

    return;
}

/**************************************************************************
w89c840_disable - Turn off ethernet interface
***************************************************************************/
static void w89c840_disable(struct nic *nic)
{
    /* Don't know what to do to disable the board. Is this needed at all? */
    /* Yes, a live NIC can corrupt the loaded memory later [Ken] */
    /* Stop the chip's Tx and Rx processes. */
    writel(w840private.csr6 &= ~0x20FA, ioaddr + NetworkConfig);
}

/**************************************************************************
w89c840_probe - Look for an adapter, this routine's visible to the outside
***************************************************************************/
struct nic *w89c840_probe(struct nic *nic, unsigned short *probe_addrs, struct pci_device *p)
{
    u16 sum = 0;
    int i, j, to;
    unsigned short value;
    int options;
    int promisc;

    if (probe_addrs == 0 || probe_addrs[0] == 0)
        return 0;

    ioaddr = probe_addrs[0]; /* Mask the bit that says "this is an io addr" */

#if defined(W89C840_DEBUG)
    printf("winbond-840: PCI bus %hhX device function %hhX: I/O address: %hX\n", p->bus, p->devfn, ioaddr);
#endif

    ioaddr = ioaddr & ~3; /* Mask the bit that says "this is an io addr" */

    /* if probe_addrs is 0, then routine can use a hardwired default */

    /* From Matt Hortman <mbhortman@acpthinclient.com> */
    if (p->vendor == PCI_VENDOR_ID_WINBOND2
        && p->dev_id == PCI_DEVICE_ID_WINBOND2_89C840) {

        /* detected "Winbond W89c840 Fast Ethernet PCI NIC" */

    } else if ( p->vendor == PCI_VENDOR_ID_COMPEX
                && p->dev_id == PCI_DEVICE_ID_COMPEX_RL100ATX) {

        /* detected "Compex RL100ATX Fast Ethernet PCI NIC" */

    } else {
        /* Gee, guess what? They missed again. */
        printf("device ID : %X - is not a Compex RL100ATX NIC.\n", p->dev_id);
        return 0;
    }

    printf(" %s\n", w89c840_version);

    adjust_pci_device(p);

    /* Ok. Got one. Read the eeprom. */
    for (j = 0, i = 0; i < 0x40; i++) {
        value = eeprom_read(ioaddr, i);
        eeprom[i] = value;
        sum += value;
    }

    for (i=0;i<ETH_ALEN;i++) {
        nic->node_addr[i] =  (eeprom[i/2] >> (8*(i&1))) & 0xff;
    }
    printf ("Ethernet addr: %!\n", nic->node_addr);

#if defined(W89C840_DEBUG)
    printf("winbond-840: EEPROM checksum %hX, got eeprom", sum);
#endif

    /* Reset the chip to erase previous misconfiguration.
       No hold time required! */
    writel(0x00000001, ioaddr + PCIBusCfg);

    if (driver_flags & CanHaveMII) {
        int phy, phy_idx = 0;
        for (phy = 1; phy < 32 && phy_idx < 4; phy++) {
            int mii_status = mdio_read(ioaddr, phy, 1);
            if (mii_status != 0xffff  &&  mii_status != 0x0000) {
                w840private.phys[phy_idx++] = phy;
                w840private.advertising = mdio_read(ioaddr, phy, 4);

#if defined(W89C840_DEBUG)
                printf("winbond-840 : MII PHY found at address %d, status "
                       "%X advertising %hX.\n", phy, mii_status, w840private.advertising);
#endif

            }
        }

        w840private.mii_cnt = phy_idx;

        if (phy_idx == 0) {
                printf("winbond-840 : MII PHY not found -- this device may not operate correctly.\n");
        }
    }

    /* point to NIC specific routines */
    nic->reset = w89c840_reset;
    nic->poll = w89c840_poll;
    nic->transmit = w89c840_transmit;
    nic->disable = w89c840_disable;

    w89c840_reset(nic);

    return nic;
}

/* Read the EEPROM and MII Management Data I/O (MDIO) interfaces.  These are
   often serial bit streams generated by the host processor.
   The example below is for the common 93c46 EEPROM, 64 16 bit words. */

/* Delay between EEPROM clock transitions.
   No extra delay is needed with 33Mhz PCI, but future 66Mhz access may need
   a delay.  Note that pre-2.0.34 kernels had a cache-alignment bug that
   made udelay() unreliable.
   The old method of using an ISA access as a delay, __SLOW_DOWN_IO__, is
   depricated.
*/
#define eeprom_delay(ee_addr)    readl(ee_addr)

enum EEPROM_Ctrl_Bits {
    EE_ShiftClk=0x02, EE_Write0=0x801, EE_Write1=0x805,
    EE_ChipSelect=0x801, EE_DataIn=0x08,
};

/* The EEPROM commands include the alway-set leading bit. */
enum EEPROM_Cmds {
    EE_WriteCmd=(5 << 6), EE_ReadCmd=(6 << 6), EE_EraseCmd=(7 << 6),
};

static int eeprom_read(long addr, int location)
{
    int i;
    int retval = 0;
    int ee_addr = addr + EECtrl;
    int read_cmd = location | EE_ReadCmd;
    writel(EE_ChipSelect, ee_addr);

    /* Shift the read command bits out. */
    for (i = 10; i >= 0; i--) {
        short dataval = (read_cmd & (1 << i)) ? EE_Write1 : EE_Write0;
        writel(dataval, ee_addr);
        eeprom_delay(ee_addr);
        writel(dataval | EE_ShiftClk, ee_addr);
        eeprom_delay(ee_addr);
    }
    writel(EE_ChipSelect, ee_addr);

    for (i = 16; i > 0; i--) {
        writel(EE_ChipSelect | EE_ShiftClk, ee_addr);
        eeprom_delay(ee_addr);
        retval = (retval << 1) | ((readl(ee_addr) & EE_DataIn) ? 1 : 0);
        writel(EE_ChipSelect, ee_addr);
        eeprom_delay(ee_addr);
    }

    /* Terminate the EEPROM access. */
    writel(0, ee_addr);
    return retval;
}

/*  MII transceiver control section.
    Read and write the MII registers using software-generated serial
    MDIO protocol.  See the MII specifications or DP83840A data sheet
    for details.

    The maximum data clock rate is 2.5 Mhz.  The minimum timing is usually
    met by back-to-back 33Mhz PCI cycles. */
#define mdio_delay(mdio_addr) readl(mdio_addr)

/* Set iff a MII transceiver on any interface requires mdio preamble.
   This only set with older tranceivers, so the extra
   code size of a per-interface flag is not worthwhile. */
static char mii_preamble_required = 1;

#define MDIO_WRITE0 (MDIO_EnbOutput)
#define MDIO_WRITE1 (MDIO_DataOut | MDIO_EnbOutput)

/* Generate the preamble required for initial synchronization and
   a few older transceivers. */
static void mdio_sync(long mdio_addr)
{
    int bits = 32;

    /* Establish sync by sending at least 32 logic ones. */
    while (--bits >= 0) {
        writel(MDIO_WRITE1, mdio_addr);
        mdio_delay(mdio_addr);
        writel(MDIO_WRITE1 | MDIO_ShiftClk, mdio_addr);
        mdio_delay(mdio_addr);
    }
}

static int mdio_read(int base_address, int phy_id, int location)
{
    long mdio_addr = base_address + MIICtrl;
    int mii_cmd = (0xf6 << 10) | (phy_id << 5) | location;
    int i, retval = 0;

    if (mii_preamble_required)
        mdio_sync(mdio_addr);

    /* Shift the read command bits out. */
    for (i = 15; i >= 0; i--) {
        int dataval = (mii_cmd & (1 << i)) ? MDIO_WRITE1 : MDIO_WRITE0;

        writel(dataval, mdio_addr);
        mdio_delay(mdio_addr);
        writel(dataval | MDIO_ShiftClk, mdio_addr);
        mdio_delay(mdio_addr);
    }
    /* Read the two transition, 16 data, and wire-idle bits. */
    for (i = 20; i > 0; i--) {
        writel(MDIO_EnbIn, mdio_addr);
        mdio_delay(mdio_addr);
        retval = (retval << 1) | ((readl(mdio_addr) & MDIO_DataIn) ? 1 : 0);
        writel(MDIO_EnbIn | MDIO_ShiftClk, mdio_addr);
        mdio_delay(mdio_addr);
    }
    return (retval>>1) & 0xffff;
}

static void mdio_write(int base_address, int phy_id, int location, int value)
{
    long mdio_addr = base_address + MIICtrl;
    int mii_cmd = (0x5002 << 16) | (phy_id << 23) | (location<<18) | value;
    int i;

    if (location == 4  &&  phy_id == w840private.phys[0])
        w840private.advertising = value;

    if (mii_preamble_required)
        mdio_sync(mdio_addr);

    /* Shift the command bits out. */
    for (i = 31; i >= 0; i--) {
        int dataval = (mii_cmd & (1 << i)) ? MDIO_WRITE1 : MDIO_WRITE0;

        writel(dataval, mdio_addr);
        mdio_delay(mdio_addr);
        writel(dataval | MDIO_ShiftClk, mdio_addr);
        mdio_delay(mdio_addr);
    }
    /* Clear out extra bits. */
    for (i = 2; i > 0; i--) {
        writel(MDIO_EnbIn, mdio_addr);
        mdio_delay(mdio_addr);
        writel(MDIO_EnbIn | MDIO_ShiftClk, mdio_addr);
        mdio_delay(mdio_addr);
    }
    return;
}

static void check_duplex(void)
{
    int mii_reg5 = mdio_read(ioaddr, w840private.phys[0], 5);
    int negotiated =  mii_reg5 & w840private.advertising;
    int duplex;

    if (w840private.duplex_lock  ||  mii_reg5 == 0xffff)
        return;

    duplex = (negotiated & 0x0100) || (negotiated & 0x01C0) == 0x0040;
    if (w840private.full_duplex != duplex) {
        w840private.full_duplex = duplex;       

#if defined(W89C840_DEBUG)
        printf("winbond-840 : Setting %s-duplex based on MII # %d negotiated capability %X\n",
               duplex ? "full" : "half", w840private.phys[0], negotiated);
#endif

        w840private.csr6 &= ~0x200;
        w840private.csr6 |= duplex ? 0x200 : 0;
    }
}

static void set_rx_mode(void)
{
    u32 mc_filter[2];            /* Multicast hash filter */
    u32 rx_mode;

    /* Accept all multicasts from now on. */
    memset(mc_filter, 0xff, sizeof(mc_filter));

/*
 * Actually, should work OK with multicast enabled. -- iko
 */
/*
 *  rx_mode = AcceptBroadcast | AcceptMyPhys | AcceptMulticast;
 */
    rx_mode = AcceptBroadcast | AcceptMyPhys;

    writel(mc_filter[0], ioaddr + MulticastFilter0);
    writel(mc_filter[1], ioaddr + MulticastFilter1);
    w840private.csr6 &= ~0x00F8;
    w840private.csr6 |= rx_mode;
    writel(w840private.csr6, ioaddr + NetworkConfig);

#if defined(W89C840_DEBUG)
    printf("winbond-840 : Done setting RX mode.\n");
#endif
}

/* Initialize the Rx and Tx rings, along with various 'dev' bits. */
static void init_ring(void)
{
    int i;
    char * p;

    w840private.tx_full = 0;
    w840private.tx_q_bytes = w840private.cur_rx = w840private.cur_tx = 0;
    w840private.dirty_rx = w840private.dirty_tx = 0;

    w840private.rx_buf_sz = PKT_BUF_SZ;
    w840private.rx_head_desc = &w840private.rx_ring[0];

    /* Initial all Rx descriptors. Fill in the Rx buffers. */

    p = &rx_packet[0];

    for (i = 0; i < RX_RING_SIZE; i++) {
        w840private.rx_ring[i].length = w840private.rx_buf_sz;
        w840private.rx_ring[i].status = 0;
        w840private.rx_ring[i].next_desc = virt_to_le32desc(&w840private.rx_ring[i+1]);

        w840private.rx_ring[i].buffer1 = virt_to_le32desc(p + (PKT_BUF_SZ * i));
        w840private.rx_ring[i].status = DescOwn | DescIntr;
    }

    /* Mark the last entry as wrapping the ring. */
    w840private.rx_ring[i-1].length |= DescEndRing;
    w840private.rx_ring[i-1].next_desc = virt_to_le32desc(&w840private.rx_ring[0]);

    w840private.dirty_rx = (unsigned int)(i - RX_RING_SIZE);

    for (i = 0; i < TX_RING_SIZE; i++) {
        w840private.tx_ring[i].status = 0;
    }
    return;
}