root/drivers/net/ethernet/i825xx/ether1.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/drivers/acorn/net/ether1.c
 *
 *  Copyright (C) 1996-2000 Russell King
 *
 *  Acorn ether1 driver (82586 chip) for Acorn machines
 *
 * We basically keep two queues in the cards memory - one for transmit
 * and one for receive.  Each has a head and a tail.  The head is where
 * we/the chip adds packets to be transmitted/received, and the tail
 * is where the transmitter has got to/where the receiver will stop.
 * Both of these queues are circular, and since the chip is running
 * all the time, we have to be careful when we modify the pointers etc
 * so that the buffer memory contents is valid all the time.
 *
 * Change log:
 * 1.00 RMK                     Released
 * 1.01 RMK     19/03/1996      Transfers the last odd byte onto/off of the card now.
 * 1.02 RMK     25/05/1997      Added code to restart RU if it goes not ready
 * 1.03 RMK     14/09/1997      Cleaned up the handling of a reset during the TX interrupt.
 *                              Should prevent lockup.
 * 1.04 RMK     17/09/1997      Added more info when initialisation of chip goes wrong.
 *                              TDR now only reports failure when chip reports non-zero
 *                              TDR time-distance.
 * 1.05 RMK     31/12/1997      Removed calls to dev_tint for 2.1
 * 1.06 RMK     10/02/2000      Updated for 2.3.43
 * 1.07 RMK     13/05/2000      Updated for 2.3.99-pre8
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/bitops.h>

#include <asm/io.h>
#include <asm/dma.h>
#include <asm/ecard.h>

#define __ETHER1_C
#include "ether1.h"

static unsigned int net_debug = NET_DEBUG;

#define BUFFER_SIZE     0x10000
#define TX_AREA_START   0x00100
#define TX_AREA_END     0x05000
#define RX_AREA_START   0x05000
#define RX_AREA_END     0x0fc00

static int ether1_open(struct net_device *dev);
static netdev_tx_t ether1_sendpacket(struct sk_buff *skb,
                                     struct net_device *dev);
static irqreturn_t ether1_interrupt(int irq, void *dev_id);
static int ether1_close(struct net_device *dev);
static void ether1_setmulticastlist(struct net_device *dev);
static void ether1_timeout(struct net_device *dev, unsigned int txqueue);

/* ------------------------------------------------------------------------- */

static char version[] = "ether1 ethernet driver (c) 2000 Russell King v1.07\n";

#define BUS_16 16
#define BUS_8  8

/* ------------------------------------------------------------------------- */

#define DISABLEIRQS 1
#define NORMALIRQS  0

#define ether1_readw(dev, addr, type, offset, svflgs) ether1_inw_p (dev, addr + (int)(&((type *)0)->offset), svflgs)
#define ether1_writew(dev, val, addr, type, offset, svflgs) ether1_outw_p (dev, val, addr + (int)(&((type *)0)->offset), svflgs)

static inline unsigned short
ether1_inw_p (struct net_device *dev, int addr, int svflgs)
{
        unsigned long flags;
        unsigned short ret;

        if (svflgs)
                local_irq_save (flags);

        writeb(addr >> 12, REG_PAGE);
        ret = readw(ETHER1_RAM + ((addr & 4095) << 1));
        if (svflgs)
                local_irq_restore (flags);
        return ret;
}

static inline void
ether1_outw_p (struct net_device *dev, unsigned short val, int addr, int svflgs)
{
        unsigned long flags;

        if (svflgs)
                local_irq_save (flags);

        writeb(addr >> 12, REG_PAGE);
        writew(val, ETHER1_RAM + ((addr & 4095) << 1));
        if (svflgs)
                local_irq_restore (flags);
}

/*
 * Some inline assembler to allow fast transfers on to/off of the card.
 * Since this driver depends on some features presented by the ARM
 * specific architecture, and that you can't configure this driver
 * without specifying ARM mode, this is not a problem.
 *
 * This routine is essentially an optimised memcpy from the card's
 * onboard RAM to kernel memory.
 */
static void
ether1_writebuffer (struct net_device *dev, void *data, unsigned int start, unsigned int length)
{
        unsigned int page, thislen, offset;
        void __iomem *addr;

        offset = start & 4095;
        page = start >> 12;
        addr = ETHER1_RAM + (offset << 1);

        if (offset + length > 4096)
                thislen = 4096 - offset;
        else
                thislen = length;

        do {
                int used;

                writeb(page, REG_PAGE);
                length -= thislen;

                __asm__ __volatile__(
        "subs   %3, %3, #2\n\
        bmi     2f\n\
1:      ldr     %0, [%1], #2\n\
        mov     %0, %0, lsl #16\n\
        orr     %0, %0, %0, lsr #16\n\
        str     %0, [%2], #4\n\
        subs    %3, %3, #2\n\
        bmi     2f\n\
        ldr     %0, [%1], #2\n\
        mov     %0, %0, lsl #16\n\
        orr     %0, %0, %0, lsr #16\n\
        str     %0, [%2], #4\n\
        subs    %3, %3, #2\n\
        bmi     2f\n\
        ldr     %0, [%1], #2\n\
        mov     %0, %0, lsl #16\n\
        orr     %0, %0, %0, lsr #16\n\
        str     %0, [%2], #4\n\
        subs    %3, %3, #2\n\
        bmi     2f\n\
        ldr     %0, [%1], #2\n\
        mov     %0, %0, lsl #16\n\
        orr     %0, %0, %0, lsr #16\n\
        str     %0, [%2], #4\n\
        subs    %3, %3, #2\n\
        bpl     1b\n\
2:      adds    %3, %3, #1\n\
        ldreqb  %0, [%1]\n\
        streqb  %0, [%2]"
                : "=&r" (used), "=&r" (data)
                : "r"  (addr), "r" (thislen), "1" (data));

                addr = ETHER1_RAM;

                thislen = length;
                if (thislen > 4096)
                        thislen = 4096;
                page++;
        } while (thislen);
}

static void
ether1_readbuffer (struct net_device *dev, void *data, unsigned int start, unsigned int length)
{
        unsigned int page, thislen, offset;
        void __iomem *addr;

        offset = start & 4095;
        page = start >> 12;
        addr = ETHER1_RAM + (offset << 1);

        if (offset + length > 4096)
                thislen = 4096 - offset;
        else
                thislen = length;

        do {
                int used;

                writeb(page, REG_PAGE);
                length -= thislen;

                __asm__ __volatile__(
        "subs   %3, %3, #2\n\
        bmi     2f\n\
1:      ldr     %0, [%2], #4\n\
        strb    %0, [%1], #1\n\
        mov     %0, %0, lsr #8\n\
        strb    %0, [%1], #1\n\
        subs    %3, %3, #2\n\
        bmi     2f\n\
        ldr     %0, [%2], #4\n\
        strb    %0, [%1], #1\n\
        mov     %0, %0, lsr #8\n\
        strb    %0, [%1], #1\n\
        subs    %3, %3, #2\n\
        bmi     2f\n\
        ldr     %0, [%2], #4\n\
        strb    %0, [%1], #1\n\
        mov     %0, %0, lsr #8\n\
        strb    %0, [%1], #1\n\
        subs    %3, %3, #2\n\
        bmi     2f\n\
        ldr     %0, [%2], #4\n\
        strb    %0, [%1], #1\n\
        mov     %0, %0, lsr #8\n\
        strb    %0, [%1], #1\n\
        subs    %3, %3, #2\n\
        bpl     1b\n\
2:      adds    %3, %3, #1\n\
        ldreqb  %0, [%2]\n\
        streqb  %0, [%1]"
                : "=&r" (used), "=&r" (data)
                : "r"  (addr), "r" (thislen), "1" (data));

                addr = ETHER1_RAM;

                thislen = length;
                if (thislen > 4096)
                        thislen = 4096;
                page++;
        } while (thislen);
}

static int
ether1_ramtest(struct net_device *dev, unsigned char byte)
{
        unsigned char *buffer = kmalloc (BUFFER_SIZE, GFP_KERNEL);
        int i, ret = BUFFER_SIZE;
        int max_errors = 15;
        int bad = -1;
        int bad_start = 0;

        if (!buffer)
                return 1;

        memset (buffer, byte, BUFFER_SIZE);
        ether1_writebuffer (dev, buffer, 0, BUFFER_SIZE);
        memset (buffer, byte ^ 0xff, BUFFER_SIZE);
        ether1_readbuffer (dev, buffer, 0, BUFFER_SIZE);

        for (i = 0; i < BUFFER_SIZE; i++) {
                if (buffer[i] != byte) {
                        if (max_errors >= 0 && bad != buffer[i]) {
                                if (bad != -1)
                                        printk ("\n");
                                printk (KERN_CRIT "%s: RAM failed with (%02X instead of %02X) at 0x%04X",
                                        dev->name, buffer[i], byte, i);
                                ret = -ENODEV;
                                max_errors --;
                                bad = buffer[i];
                                bad_start = i;
                        }
                } else {
                        if (bad != -1) {
                                if (bad_start == i - 1)
                                        printk ("\n");
                                else
                                        printk (" - 0x%04X\n", i - 1);
                                bad = -1;
                        }
                }
        }

        if (bad != -1)
                printk (" - 0x%04X\n", BUFFER_SIZE);
        kfree (buffer);

        return ret;
}

static int
ether1_reset (struct net_device *dev)
{
        writeb(CTRL_RST|CTRL_ACK, REG_CONTROL);
        return BUS_16;
}

static int
ether1_init_2(struct net_device *dev)
{
        int i;
        dev->mem_start = 0;

        i = ether1_ramtest (dev, 0x5a);

        if (i > 0)
                i = ether1_ramtest (dev, 0x1e);

        if (i <= 0)
                return -ENODEV;

        dev->mem_end = i;
        return 0;
}

/*
 * These are the structures that are loaded into the ether RAM card to
 * initialise the 82586
 */

/* at 0x0100 */
#define NOP_ADDR        (TX_AREA_START)
#define NOP_SIZE        (0x06)
static nop_t  init_nop  = {
        0,
        CMD_NOP,
        NOP_ADDR
};

/* at 0x003a */
#define TDR_ADDR        (0x003a)
#define TDR_SIZE        (0x08)
static tdr_t  init_tdr  = {
        0,
        CMD_TDR | CMD_INTR,
        NOP_ADDR,
        0
};

/* at 0x002e */
#define MC_ADDR         (0x002e)
#define MC_SIZE         (0x0c)
static mc_t   init_mc   = {
        0,
        CMD_SETMULTICAST,
        TDR_ADDR,
        0,
        { { 0, } }
};

/* at 0x0022 */
#define SA_ADDR         (0x0022)
#define SA_SIZE         (0x0c)
static sa_t   init_sa   = {
        0,
        CMD_SETADDRESS,
        MC_ADDR,
        { 0, }
};

/* at 0x0010 */
#define CFG_ADDR        (0x0010)
#define CFG_SIZE        (0x12)
static cfg_t  init_cfg  = {
        0,
        CMD_CONFIG,
        SA_ADDR,
        8,
        8,
        CFG8_SRDY,
        CFG9_PREAMB8 | CFG9_ADDRLENBUF | CFG9_ADDRLEN(6),
        0,
        0x60,
        0,
        CFG13_RETRY(15) | CFG13_SLOTH(2),
        0,
};

/* at 0x0000 */
#define SCB_ADDR        (0x0000)
#define SCB_SIZE        (0x10)
static scb_t  init_scb  = {
        0,
        SCB_CMDACKRNR | SCB_CMDACKCNA | SCB_CMDACKFR | SCB_CMDACKCX,
        CFG_ADDR,
        RX_AREA_START,
        0,
        0,
        0,
        0
};

/* at 0xffee */
#define ISCP_ADDR       (0xffee)
#define ISCP_SIZE       (0x08)
static iscp_t init_iscp = {
        1,
        SCB_ADDR,
        0x0000,
        0x0000
};

/* at 0xfff6 */
#define SCP_ADDR        (0xfff6)
#define SCP_SIZE        (0x0a)
static scp_t  init_scp  = {
        SCP_SY_16BBUS,
        { 0, 0 },
        ISCP_ADDR,
        0
};

#define RFD_SIZE        (0x16)
static rfd_t  init_rfd  = {
        0,
        0,
        0,
        0,
        { 0, },
        { 0, },
        0
};

#define RBD_SIZE        (0x0a)
static rbd_t  init_rbd  = {
        0,
        0,
        0,
        0,
        ETH_FRAME_LEN + 8
};

#define TX_SIZE         (0x08)
#define TBD_SIZE        (0x08)

static int
ether1_init_for_open (struct net_device *dev)
{
        int i, status, addr, next, next2;
        int failures = 0;
        unsigned long timeout;

        writeb(CTRL_RST|CTRL_ACK, REG_CONTROL);

        for (i = 0; i < 6; i++)
                init_sa.sa_addr[i] = dev->dev_addr[i];

        /* load data structures into ether1 RAM */
        ether1_writebuffer (dev, &init_scp,  SCP_ADDR,  SCP_SIZE);
        ether1_writebuffer (dev, &init_iscp, ISCP_ADDR, ISCP_SIZE);
        ether1_writebuffer (dev, &init_scb,  SCB_ADDR,  SCB_SIZE);
        ether1_writebuffer (dev, &init_cfg,  CFG_ADDR,  CFG_SIZE);
        ether1_writebuffer (dev, &init_sa,   SA_ADDR,   SA_SIZE);
        ether1_writebuffer (dev, &init_mc,   MC_ADDR,   MC_SIZE);
        ether1_writebuffer (dev, &init_tdr,  TDR_ADDR,  TDR_SIZE);
        ether1_writebuffer (dev, &init_nop,  NOP_ADDR,  NOP_SIZE);

        if (ether1_readw(dev, CFG_ADDR, cfg_t, cfg_command, NORMALIRQS) != CMD_CONFIG) {
                printk (KERN_ERR "%s: detected either RAM fault or compiler bug\n",
                        dev->name);
                return 1;
        }

        /*
         * setup circularly linked list of { rfd, rbd, buffer }, with
         * all rfds circularly linked, rbds circularly linked.
         * First rfd is linked to scp, first rbd is linked to first
         * rfd.  Last rbd has a suspend command.
         */
        addr = RX_AREA_START;
        do {
                next = addr + RFD_SIZE + RBD_SIZE + ETH_FRAME_LEN + 10;
                next2 = next + RFD_SIZE + RBD_SIZE + ETH_FRAME_LEN + 10;

                if (next2 >= RX_AREA_END) {
                        next = RX_AREA_START;
                        init_rfd.rfd_command = RFD_CMDEL | RFD_CMDSUSPEND;
                        priv(dev)->rx_tail = addr;
                } else
                        init_rfd.rfd_command = 0;
                if (addr == RX_AREA_START)
                        init_rfd.rfd_rbdoffset = addr + RFD_SIZE;
                else
                        init_rfd.rfd_rbdoffset = 0;
                init_rfd.rfd_link = next;
                init_rbd.rbd_link = next + RFD_SIZE;
                init_rbd.rbd_bufl = addr + RFD_SIZE + RBD_SIZE;

                ether1_writebuffer (dev, &init_rfd, addr, RFD_SIZE);
                ether1_writebuffer (dev, &init_rbd, addr + RFD_SIZE, RBD_SIZE);
                addr = next;
        } while (next2 < RX_AREA_END);

        priv(dev)->tx_link = NOP_ADDR;
        priv(dev)->tx_head = NOP_ADDR + NOP_SIZE;
        priv(dev)->tx_tail = TDR_ADDR;
        priv(dev)->rx_head = RX_AREA_START;

        /* release reset & give 586 a prod */
        priv(dev)->resetting = 1;
        priv(dev)->initialising = 1;
        writeb(CTRL_RST, REG_CONTROL);
        writeb(0, REG_CONTROL);
        writeb(CTRL_CA, REG_CONTROL);

        /* 586 should now unset iscp.busy */
        timeout = jiffies + HZ/2;
        while (ether1_readw(dev, ISCP_ADDR, iscp_t, iscp_busy, DISABLEIRQS) == 1) {
                if (time_after(jiffies, timeout)) {
                        printk (KERN_WARNING "%s: can't initialise 82586: iscp is busy\n", dev->name);
                        return 1;
                }
        }

        /* check status of commands that we issued */
        timeout += HZ/10;
        while (((status = ether1_readw(dev, CFG_ADDR, cfg_t, cfg_status, DISABLEIRQS))
                        & STAT_COMPLETE) == 0) {
                if (time_after(jiffies, timeout))
                        break;
        }

        if ((status & (STAT_COMPLETE | STAT_OK)) != (STAT_COMPLETE | STAT_OK)) {
                printk (KERN_WARNING "%s: can't initialise 82586: config status %04X\n", dev->name, status);
                printk (KERN_DEBUG "%s: SCB=[STS=%04X CMD=%04X CBL=%04X RFA=%04X]\n", dev->name,
                        ether1_readw(dev, SCB_ADDR, scb_t, scb_status, NORMALIRQS),
                        ether1_readw(dev, SCB_ADDR, scb_t, scb_command, NORMALIRQS),
                        ether1_readw(dev, SCB_ADDR, scb_t, scb_cbl_offset, NORMALIRQS),
                        ether1_readw(dev, SCB_ADDR, scb_t, scb_rfa_offset, NORMALIRQS));
                failures += 1;
        }

        timeout += HZ/10;
        while (((status = ether1_readw(dev, SA_ADDR, sa_t, sa_status, DISABLEIRQS))
                        & STAT_COMPLETE) == 0) {
                if (time_after(jiffies, timeout))
                        break;
        }

        if ((status & (STAT_COMPLETE | STAT_OK)) != (STAT_COMPLETE | STAT_OK)) {
                printk (KERN_WARNING "%s: can't initialise 82586: set address status %04X\n", dev->name, status);
                printk (KERN_DEBUG "%s: SCB=[STS=%04X CMD=%04X CBL=%04X RFA=%04X]\n", dev->name,
                        ether1_readw(dev, SCB_ADDR, scb_t, scb_status, NORMALIRQS),
                        ether1_readw(dev, SCB_ADDR, scb_t, scb_command, NORMALIRQS),
                        ether1_readw(dev, SCB_ADDR, scb_t, scb_cbl_offset, NORMALIRQS),
                        ether1_readw(dev, SCB_ADDR, scb_t, scb_rfa_offset, NORMALIRQS));
                failures += 1;
        }

        timeout += HZ/10;
        while (((status = ether1_readw(dev, MC_ADDR, mc_t, mc_status, DISABLEIRQS))
                        & STAT_COMPLETE) == 0) {
                if (time_after(jiffies, timeout))
                        break;
        }

        if ((status & (STAT_COMPLETE | STAT_OK)) != (STAT_COMPLETE | STAT_OK)) {
                printk (KERN_WARNING "%s: can't initialise 82586: set multicast status %04X\n", dev->name, status);
                printk (KERN_DEBUG "%s: SCB=[STS=%04X CMD=%04X CBL=%04X RFA=%04X]\n", dev->name,
                        ether1_readw(dev, SCB_ADDR, scb_t, scb_status, NORMALIRQS),
                        ether1_readw(dev, SCB_ADDR, scb_t, scb_command, NORMALIRQS),
                        ether1_readw(dev, SCB_ADDR, scb_t, scb_cbl_offset, NORMALIRQS),
                        ether1_readw(dev, SCB_ADDR, scb_t, scb_rfa_offset, NORMALIRQS));
                failures += 1;
        }

        timeout += HZ;
        while (((status = ether1_readw(dev, TDR_ADDR, tdr_t, tdr_status, DISABLEIRQS))
                        & STAT_COMPLETE) == 0) {
                if (time_after(jiffies, timeout))
                        break;
        }

        if ((status & (STAT_COMPLETE | STAT_OK)) != (STAT_COMPLETE | STAT_OK)) {
                printk (KERN_WARNING "%s: can't tdr (ignored)\n", dev->name);
                printk (KERN_DEBUG "%s: SCB=[STS=%04X CMD=%04X CBL=%04X RFA=%04X]\n", dev->name,
                        ether1_readw(dev, SCB_ADDR, scb_t, scb_status, NORMALIRQS),
                        ether1_readw(dev, SCB_ADDR, scb_t, scb_command, NORMALIRQS),
                        ether1_readw(dev, SCB_ADDR, scb_t, scb_cbl_offset, NORMALIRQS),
                        ether1_readw(dev, SCB_ADDR, scb_t, scb_rfa_offset, NORMALIRQS));
        } else {
                status = ether1_readw(dev, TDR_ADDR, tdr_t, tdr_result, DISABLEIRQS);
                if (status & TDR_XCVRPROB)
                        printk (KERN_WARNING "%s: i/f failed tdr: transceiver problem\n", dev->name);
                else if ((status & (TDR_SHORT|TDR_OPEN)) && (status & TDR_TIME)) {
#ifdef FANCY
                        printk (KERN_WARNING "%s: i/f failed tdr: cable %s %d.%d us away\n", dev->name,
                                status & TDR_SHORT ? "short" : "open", (status & TDR_TIME) / 10,
                                (status & TDR_TIME) % 10);
#else
                        printk (KERN_WARNING "%s: i/f failed tdr: cable %s %d clks away\n", dev->name,
                                status & TDR_SHORT ? "short" : "open", (status & TDR_TIME));
#endif
                }
        }

        if (failures)
                ether1_reset (dev);
        return failures ? 1 : 0;
}

/* ------------------------------------------------------------------------- */

static int
ether1_txalloc (struct net_device *dev, int size)
{
        int start, tail;

        size = (size + 1) & ~1;
        tail = priv(dev)->tx_tail;

        if (priv(dev)->tx_head + size > TX_AREA_END) {
                if (tail > priv(dev)->tx_head)
                        return -1;
                start = TX_AREA_START;
                if (start + size > tail)
                        return -1;
                priv(dev)->tx_head = start + size;
        } else {
                if (priv(dev)->tx_head < tail && (priv(dev)->tx_head + size) > tail)
                        return -1;
                start = priv(dev)->tx_head;
                priv(dev)->tx_head += size;
        }

        return start;
}

static int
ether1_open (struct net_device *dev)
{
        if (request_irq(dev->irq, ether1_interrupt, 0, "ether1", dev))
                return -EAGAIN;

        if (ether1_init_for_open (dev)) {
                free_irq (dev->irq, dev);
                return -EAGAIN;
        }

        netif_start_queue(dev);

        return 0;
}

static void
ether1_timeout(struct net_device *dev, unsigned int txqueue)
{
        printk(KERN_WARNING "%s: transmit timeout, network cable problem?\n",
                dev->name);
        printk(KERN_WARNING "%s: resetting device\n", dev->name);

        ether1_reset (dev);

        if (ether1_init_for_open (dev))
                printk (KERN_ERR "%s: unable to restart interface\n", dev->name);

        dev->stats.tx_errors++;
        netif_wake_queue(dev);
}

static netdev_tx_t
ether1_sendpacket (struct sk_buff *skb, struct net_device *dev)
{
        int tmp, tst, nopaddr, txaddr, tbdaddr, dataddr;
        unsigned long flags;
        tx_t tx;
        tbd_t tbd;
        nop_t nop;

        if (priv(dev)->restart) {
                printk(KERN_WARNING "%s: resetting device\n", dev->name);

                ether1_reset(dev);

                if (ether1_init_for_open(dev))
                        printk(KERN_ERR "%s: unable to restart interface\n", dev->name);
                else
                        priv(dev)->restart = 0;
        }

        if (skb->len < ETH_ZLEN) {
                if (skb_padto(skb, ETH_ZLEN))
                        goto out;
        }

        /*
         * insert packet followed by a nop
         */
        txaddr = ether1_txalloc (dev, TX_SIZE);
        tbdaddr = ether1_txalloc (dev, TBD_SIZE);
        dataddr = ether1_txalloc (dev, skb->len);
        nopaddr = ether1_txalloc (dev, NOP_SIZE);

        tx.tx_status = 0;
        tx.tx_command = CMD_TX | CMD_INTR;
        tx.tx_link = nopaddr;
        tx.tx_tbdoffset = tbdaddr;
        tbd.tbd_opts = TBD_EOL | skb->len;
        tbd.tbd_link = I82586_NULL;
        tbd.tbd_bufl = dataddr;
        tbd.tbd_bufh = 0;
        nop.nop_status = 0;
        nop.nop_command = CMD_NOP;
        nop.nop_link = nopaddr;

        local_irq_save(flags);
        ether1_writebuffer (dev, &tx, txaddr, TX_SIZE);
        ether1_writebuffer (dev, &tbd, tbdaddr, TBD_SIZE);
        ether1_writebuffer (dev, skb->data, dataddr, skb->len);
        ether1_writebuffer (dev, &nop, nopaddr, NOP_SIZE);
        tmp = priv(dev)->tx_link;
        priv(dev)->tx_link = nopaddr;

        /* now reset the previous nop pointer */
        ether1_writew(dev, txaddr, tmp, nop_t, nop_link, NORMALIRQS);

        local_irq_restore(flags);

        /* handle transmit */

        /* check to see if we have room for a full sized ether frame */
        tmp = priv(dev)->tx_head;
        tst = ether1_txalloc (dev, TX_SIZE + TBD_SIZE + NOP_SIZE + ETH_FRAME_LEN);
        priv(dev)->tx_head = tmp;
        dev_kfree_skb (skb);

        if (tst == -1)
                netif_stop_queue(dev);

 out:
        return NETDEV_TX_OK;
}

static void
ether1_xmit_done (struct net_device *dev)
{
        nop_t nop;
        int caddr, tst;

        caddr = priv(dev)->tx_tail;

again:
        ether1_readbuffer (dev, &nop, caddr, NOP_SIZE);

        switch (nop.nop_command & CMD_MASK) {
        case CMD_TDR:
                /* special case */
                if (ether1_readw(dev, SCB_ADDR, scb_t, scb_cbl_offset, NORMALIRQS)
                                != (unsigned short)I82586_NULL) {
                        ether1_writew(dev, SCB_CMDCUCSTART | SCB_CMDRXSTART, SCB_ADDR, scb_t,
                                    scb_command, NORMALIRQS);
                        writeb(CTRL_CA, REG_CONTROL);
                }
                priv(dev)->tx_tail = NOP_ADDR;
                return;

        case CMD_NOP:
                if (nop.nop_link == caddr) {
                        if (priv(dev)->initialising == 0)
                                printk (KERN_WARNING "%s: strange command complete with no tx command!\n", dev->name);
                        else
                                priv(dev)->initialising = 0;
                        return;
                }
                if (caddr == nop.nop_link)
                        return;
                caddr = nop.nop_link;
                goto again;

        case CMD_TX:
                if (nop.nop_status & STAT_COMPLETE)
                        break;
                printk (KERN_ERR "%s: strange command complete without completed command\n", dev->name);
                priv(dev)->restart = 1;
                return;

        default:
                printk (KERN_WARNING "%s: strange command %d complete! (offset %04X)", dev->name,
                        nop.nop_command & CMD_MASK, caddr);
                priv(dev)->restart = 1;
                return;
        }

        while (nop.nop_status & STAT_COMPLETE) {
                if (nop.nop_status & STAT_OK) {
                        dev->stats.tx_packets++;
                        dev->stats.collisions += (nop.nop_status & STAT_COLLISIONS);
                } else {
                        dev->stats.tx_errors++;

                        if (nop.nop_status & STAT_COLLAFTERTX)
                                dev->stats.collisions++;
                        if (nop.nop_status & STAT_NOCARRIER)
                                dev->stats.tx_carrier_errors++;
                        if (nop.nop_status & STAT_TXLOSTCTS)
                                printk (KERN_WARNING "%s: cts lost\n", dev->name);
                        if (nop.nop_status & STAT_TXSLOWDMA)
                                dev->stats.tx_fifo_errors++;
                        if (nop.nop_status & STAT_COLLEXCESSIVE)
                                dev->stats.collisions += 16;
                }

                if (nop.nop_link == caddr) {
                        printk (KERN_ERR "%s: tx buffer chaining error: tx command points to itself\n", dev->name);
                        break;
                }

                caddr = nop.nop_link;
                ether1_readbuffer (dev, &nop, caddr, NOP_SIZE);
                if ((nop.nop_command & CMD_MASK) != CMD_NOP) {
                        printk (KERN_ERR "%s: tx buffer chaining error: no nop after tx command\n", dev->name);
                        break;
                }

                if (caddr == nop.nop_link)
                        break;

                caddr = nop.nop_link;
                ether1_readbuffer (dev, &nop, caddr, NOP_SIZE);
                if ((nop.nop_command & CMD_MASK) != CMD_TX) {
                        printk (KERN_ERR "%s: tx buffer chaining error: no tx command after nop\n", dev->name);
                        break;
                }
        }
        priv(dev)->tx_tail = caddr;

        caddr = priv(dev)->tx_head;
        tst = ether1_txalloc (dev, TX_SIZE + TBD_SIZE + NOP_SIZE + ETH_FRAME_LEN);
        priv(dev)->tx_head = caddr;
        if (tst != -1)
                netif_wake_queue(dev);
}

static void
ether1_recv_done (struct net_device *dev)
{
        int status;
        int nexttail, rbdaddr;
        rbd_t rbd;

        do {
                status = ether1_readw(dev, priv(dev)->rx_head, rfd_t, rfd_status, NORMALIRQS);
                if ((status & RFD_COMPLETE) == 0)
                        break;

                rbdaddr = ether1_readw(dev, priv(dev)->rx_head, rfd_t, rfd_rbdoffset, NORMALIRQS);
                ether1_readbuffer (dev, &rbd, rbdaddr, RBD_SIZE);

                if ((rbd.rbd_status & (RBD_EOF | RBD_ACNTVALID)) == (RBD_EOF | RBD_ACNTVALID)) {
                        int length = rbd.rbd_status & RBD_ACNT;
                        struct sk_buff *skb;

                        length = (length + 1) & ~1;
                        skb = netdev_alloc_skb(dev, length + 2);

                        if (skb) {
                                skb_reserve (skb, 2);

                                ether1_readbuffer (dev, skb_put (skb, length), rbd.rbd_bufl, length);

                                skb->protocol = eth_type_trans (skb, dev);
                                netif_rx (skb);
                                dev->stats.rx_packets++;
                        } else
                                dev->stats.rx_dropped++;
                } else {
                        printk(KERN_WARNING "%s: %s\n", dev->name,
                                (rbd.rbd_status & RBD_EOF) ? "oversized packet" : "acnt not valid");
                        dev->stats.rx_dropped++;
                }

                nexttail = ether1_readw(dev, priv(dev)->rx_tail, rfd_t, rfd_link, NORMALIRQS);
                /* nexttail should be rx_head */
                if (nexttail != priv(dev)->rx_head)
                        printk(KERN_ERR "%s: receiver buffer chaining error (%04X != %04X)\n",
                                dev->name, nexttail, priv(dev)->rx_head);
                ether1_writew(dev, RFD_CMDEL | RFD_CMDSUSPEND, nexttail, rfd_t, rfd_command, NORMALIRQS);
                ether1_writew(dev, 0, priv(dev)->rx_tail, rfd_t, rfd_command, NORMALIRQS);
                ether1_writew(dev, 0, priv(dev)->rx_tail, rfd_t, rfd_status, NORMALIRQS);
                ether1_writew(dev, 0, priv(dev)->rx_tail, rfd_t, rfd_rbdoffset, NORMALIRQS);
        
                priv(dev)->rx_tail = nexttail;
                priv(dev)->rx_head = ether1_readw(dev, priv(dev)->rx_head, rfd_t, rfd_link, NORMALIRQS);
        } while (1);
}

static irqreturn_t
ether1_interrupt (int irq, void *dev_id)
{
        struct net_device *dev = (struct net_device *)dev_id;
        int status;

        status = ether1_readw(dev, SCB_ADDR, scb_t, scb_status, NORMALIRQS);

        if (status) {
                ether1_writew(dev, status & (SCB_STRNR | SCB_STCNA | SCB_STFR | SCB_STCX),
                            SCB_ADDR, scb_t, scb_command, NORMALIRQS);
                writeb(CTRL_CA | CTRL_ACK, REG_CONTROL);
                if (status & SCB_STCX) {
                        ether1_xmit_done (dev);
                }
                if (status & SCB_STCNA) {
                        if (priv(dev)->resetting == 0)
                                printk (KERN_WARNING "%s: CU went not ready ???\n", dev->name);
                        else
                                priv(dev)->resetting += 1;
                        if (ether1_readw(dev, SCB_ADDR, scb_t, scb_cbl_offset, NORMALIRQS)
                                        != (unsigned short)I82586_NULL) {
                                ether1_writew(dev, SCB_CMDCUCSTART, SCB_ADDR, scb_t, scb_command, NORMALIRQS);
                                writeb(CTRL_CA, REG_CONTROL);
                        }
                        if (priv(dev)->resetting == 2)
                                priv(dev)->resetting = 0;
                }
                if (status & SCB_STFR) {
                        ether1_recv_done (dev);
                }
                if (status & SCB_STRNR) {
                        if (ether1_readw(dev, SCB_ADDR, scb_t, scb_status, NORMALIRQS) & SCB_STRXSUSP) {
                                printk (KERN_WARNING "%s: RU went not ready: RU suspended\n", dev->name);
                                ether1_writew(dev, SCB_CMDRXRESUME, SCB_ADDR, scb_t, scb_command, NORMALIRQS);
                                writeb(CTRL_CA, REG_CONTROL);
                                dev->stats.rx_dropped++;        /* we suspended due to lack of buffer space */
                        } else
                                printk(KERN_WARNING "%s: RU went not ready: %04X\n", dev->name,
                                        ether1_readw(dev, SCB_ADDR, scb_t, scb_status, NORMALIRQS));
                        printk (KERN_WARNING "RU ptr = %04X\n", ether1_readw(dev, SCB_ADDR, scb_t, scb_rfa_offset,
                                                NORMALIRQS));
                }
        } else
                writeb(CTRL_ACK, REG_CONTROL);

        return IRQ_HANDLED;
}

static int
ether1_close (struct net_device *dev)
{
        ether1_reset (dev);

        free_irq(dev->irq, dev);

        return 0;
}

/*
 * Set or clear the multicast filter for this adaptor.
 * num_addrs == -1      Promiscuous mode, receive all packets.
 * num_addrs == 0       Normal mode, clear multicast list.
 * num_addrs > 0        Multicast mode, receive normal and MC packets, and do
 *                      best-effort filtering.
 */
static void
ether1_setmulticastlist (struct net_device *dev)
{
}

/* ------------------------------------------------------------------------- */

static void ether1_banner(void)
{
        static unsigned int version_printed = 0;

        if (net_debug && version_printed++ == 0)
                printk(KERN_INFO "%s", version);
}

static const struct net_device_ops ether1_netdev_ops = {
        .ndo_open               = ether1_open,
        .ndo_stop               = ether1_close,
        .ndo_start_xmit         = ether1_sendpacket,
        .ndo_set_rx_mode        = ether1_setmulticastlist,
        .ndo_tx_timeout         = ether1_timeout,
        .ndo_validate_addr      = eth_validate_addr,
        .ndo_set_mac_address    = eth_mac_addr,
};

static int
ether1_probe(struct expansion_card *ec, const struct ecard_id *id)
{
        struct net_device *dev;
        u8 addr[ETH_ALEN];
        int i, ret = 0;

        ether1_banner();

        ret = ecard_request_resources(ec);
        if (ret)
                goto out;

        dev = alloc_etherdev(sizeof(struct ether1_priv));
        if (!dev) {
                ret = -ENOMEM;
                goto release;
        }

        SET_NETDEV_DEV(dev, &ec->dev);

        dev->irq = ec->irq;
        priv(dev)->base = ecardm_iomap(ec, ECARD_RES_IOCFAST, 0, 0);
        if (!priv(dev)->base) {
                ret = -ENOMEM;
                goto free;
        }

        if ((priv(dev)->bus_type = ether1_reset(dev)) == 0) {
                ret = -ENODEV;
                goto free;
        }

        for (i = 0; i < 6; i++)
                addr[i] = readb(IDPROM_ADDRESS + (i << 2));
        eth_hw_addr_set(dev, addr);

        if (ether1_init_2(dev)) {
                ret = -ENODEV;
                goto free;
        }

        dev->netdev_ops         = &ether1_netdev_ops;
        dev->watchdog_timeo     = 5 * HZ / 100;

        ret = register_netdev(dev);
        if (ret)
                goto free;

        printk(KERN_INFO "%s: ether1 in slot %d, %pM\n",
                dev->name, ec->slot_no, dev->dev_addr);
    
        ecard_set_drvdata(ec, dev);
        return 0;

 free:
        free_netdev(dev);
 release:
        ecard_release_resources(ec);
 out:
        return ret;
}

static void ether1_remove(struct expansion_card *ec)
{
        struct net_device *dev = ecard_get_drvdata(ec);

        ecard_set_drvdata(ec, NULL);    

        unregister_netdev(dev);
        free_netdev(dev);
        ecard_release_resources(ec);
}

static const struct ecard_id ether1_ids[] = {
        { MANU_ACORN, PROD_ACORN_ETHER1 },
        { 0xffff, 0xffff }
};

static struct ecard_driver ether1_driver = {
        .probe          = ether1_probe,
        .remove         = ether1_remove,
        .id_table       = ether1_ids,
        .drv = {
                .name   = "ether1",
        },
};

static int __init ether1_init(void)
{
        return ecard_register_driver(&ether1_driver);
}

static void __exit ether1_exit(void)
{
        ecard_remove_driver(&ether1_driver);
}

module_init(ether1_init);
module_exit(ether1_exit);

MODULE_LICENSE("GPL");