/*      $NetBSD: ne2000.c,v 1.79 2024/05/21 08:04:20 andvar Exp $       */

/*-
 * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Device driver for National Semiconductor DS8390/WD83C690 based ethernet
 * adapters.
 *
 * Copyright (c) 1994, 1995 Charles M. Hannum.  All rights reserved.
 *
 * Copyright (C) 1993, David Greenman.  This software may be used, modified,
 * copied, distributed, and sold, in both source and binary form provided that
 * the above copyright and these terms are retained.  Under no circumstances is
 * the author responsible for the proper functioning of this software, nor does
 * the author assume any responsibility for damages incurred with its use.
 */

/*
 * Common code shared by all NE2000-compatible Ethernet interfaces.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ne2000.c,v 1.79 2024/05/21 08:04:20 andvar Exp $");

#include "rtl80x9.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/socket.h>
#include <sys/mbuf.h>
#include <sys/syslog.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/if_media.h>

#include <net/if_ether.h>

#include <sys/bswap.h>
#include <sys/bus.h>

#ifndef __BUS_SPACE_HAS_STREAM_METHODS
#define bus_space_write_stream_2        bus_space_write_2
#define bus_space_write_multi_stream_2  bus_space_write_multi_2
#define bus_space_read_multi_stream_2   bus_space_read_multi_2
#endif /* __BUS_SPACE_HAS_STREAM_METHODS */

#include <dev/ic/dp8390reg.h>
#include <dev/ic/dp8390var.h>

#include <dev/ic/ne2000reg.h>
#include <dev/ic/ne2000var.h>

#include <dev/ic/rtl80x9reg.h>
#include <dev/ic/rtl80x9var.h>

#include <dev/ic/ax88190reg.h>

static int      ne2000_write_mbuf(struct dp8390_softc *, struct mbuf *, int);
static int      ne2000_ring_copy(struct dp8390_softc *, int, void *, u_short);
static void     ne2000_read_hdr(struct dp8390_softc *, int,
                    struct dp8390_ring *);
static int      ne2000_test_mem(struct dp8390_softc *);

static void     ne2000_writemem(bus_space_tag_t, bus_space_handle_t,
                    bus_space_tag_t, bus_space_handle_t, const uint8_t *, int,
                    size_t, int, int);
static void     ne2000_readmem(bus_space_tag_t, bus_space_handle_t,
                    bus_space_tag_t, bus_space_handle_t, int, uint8_t *,
                    size_t, int);

#ifdef NE2000_DETECT_8BIT
static bool     ne2000_detect_8bit(bus_space_tag_t, bus_space_handle_t,
                    bus_space_tag_t, bus_space_handle_t);
#endif

#define ASIC_BARRIER(asict, asich) \
        bus_space_barrier((asict), (asich), 0, 0x10, \
            BUS_SPACE_BARRIER_READ | BUS_SPACE_BARRIER_WRITE)

int
ne2000_attach(struct ne2000_softc *nsc, uint8_t *myea)
{
        struct dp8390_softc *dsc = &nsc->sc_dp8390;
        bus_space_tag_t nict = dsc->sc_regt;
        bus_space_handle_t nich = dsc->sc_regh;
        bus_space_tag_t asict = nsc->sc_asict;
        bus_space_handle_t asich = nsc->sc_asich;
        uint8_t romdata[16];
        int memstart, memsize, i, useword;

        /*
         * Detect it again unless caller specified it; this gives us
         * the memory size.
         */
        if (nsc->sc_type == NE2000_TYPE_UNKNOWN)
                nsc->sc_type = ne2000_detect(nict, nich, asict, asich);

        /*
         * 8k of memory for NE1000, 16k for NE2000 and 24k for the
         * card uses DL10019.
         */
        switch (nsc->sc_type) {
        case NE2000_TYPE_UNKNOWN:
        default:
                aprint_error_dev(dsc->sc_dev, "where did the card go?\n");
                return 1;
        case NE2000_TYPE_NE1000:
                memstart = 8192;
                memsize = 8192;
                useword = 0;
                break;
        case NE2000_TYPE_NE2000:
        case NE2000_TYPE_AX88190:               /* XXX really? */
        case NE2000_TYPE_AX88790:
        case NE2000_TYPE_AX88796:
#if NRTL80X9 > 0
        case NE2000_TYPE_RTL8019:
#endif
                memstart = 16384;
                memsize = 16384;
                useword = 1;

                if (
#ifdef NE2000_DETECT_8BIT
                    ne2000_detect_8bit(nict, nich, asict, asich) ||
#endif
                    (nsc->sc_quirk & NE2000_QUIRK_8BIT) != 0) {
                        /* in 8 bit mode, only 8KB memory can be used */
                        memsize = 8192;
                        useword = 0;
                }
                break;
        case NE2000_TYPE_DL10019:
        case NE2000_TYPE_DL10022:
                memstart = 8192 * 3;
                memsize = 8192 * 3;
                useword = 1;
                break;
        }

        nsc->sc_useword = useword;
#if NRTL80X9 > 0
        if (nsc->sc_type == NE2000_TYPE_RTL8019) {
                dsc->init_card = rtl80x9_init_card;
                dsc->sc_media_init = rtl80x9_media_init;
                dsc->sc_mediachange = rtl80x9_mediachange;
                dsc->sc_mediastatus = rtl80x9_mediastatus;
        }
#endif

        dsc->cr_proto = ED_CR_RD2;
        if (nsc->sc_type == NE2000_TYPE_AX88190 ||
            nsc->sc_type == NE2000_TYPE_AX88790) {
                dsc->rcr_proto = ED_RCR_INTT;
                dsc->sc_flags |= DP8390_DO_AX88190_WORKAROUND;
        } else
                dsc->rcr_proto = 0;

        /*
         * DCR gets:
         *
         *      FIFO threshold to 8, No auto-init Remote DMA,
         *      byte order=80x86.
         *
         * NE1000 gets byte-wide DMA, NE2000 gets word-wide DMA.
         */
        dsc->dcr_reg = ED_DCR_FT1 | ED_DCR_LS | (useword ? ED_DCR_WTS : 0);

        dsc->test_mem = ne2000_test_mem;
        dsc->ring_copy = ne2000_ring_copy;
        dsc->write_mbuf = ne2000_write_mbuf;
        dsc->read_hdr = ne2000_read_hdr;

        /* Registers are linear. */
        for (i = 0; i < 16; i++)
                dsc->sc_reg_map[i] = i;

        /*
         * NIC memory doesn't start at zero on an NE board.
         * The start address is tied to the bus width.
         */
#ifdef GWETHER
        {
                int x;
                int8_t pbuf0[ED_PAGE_SIZE], pbuf[ED_PAGE_SIZE],
                    tbuf[ED_PAGE_SIZE];

                memstart = 0;
                for (i = 0; i < ED_PAGE_SIZE; i++)
                        pbuf0[i] = 0;

                /* Search for the start of RAM. */
                for (x = 1; x < 256; x++) {
                        ne2000_writemem(nict, nich, asict, asich, pbuf0,
                            x << ED_PAGE_SHIFT, ED_PAGE_SIZE, useword, 0);
                        ne2000_readmem(nict, nich, asict, asich,
                            x << ED_PAGE_SHIFT, tbuf, ED_PAGE_SIZE, useword);
                        if (memcmp(pbuf0, tbuf, ED_PAGE_SIZE) == 0) {
                                for (i = 0; i < ED_PAGE_SIZE; i++)
                                        pbuf[i] = 255 - x;
                                ne2000_writemem(nict, nich, asict, asich,
                                    pbuf, x << ED_PAGE_SHIFT, ED_PAGE_SIZE,
                                    useword, 0);
                                ne2000_readmem(nict, nich, asict, asich,
                                    x << ED_PAGE_SHIFT, tbuf, ED_PAGE_SIZE,
                                    useword);
                                if (memcmp(pbuf, tbuf, ED_PAGE_SIZE) == 0) {
                                        memstart = x << ED_PAGE_SHIFT;
                                        memsize = ED_PAGE_SIZE;
                                        break;
                                }
                        }
                }

                if (memstart == 0) {
                        aprint_error_dev(dsc->sc_dev,
                            "cannot find start of RAM\n");
                        return 1;
                }

                /* Search for the end of RAM. */
                for (++x; x < 256; x++) {
                        ne2000_writemem(nict, nich, asict, asich, pbuf0,
                            x << ED_PAGE_SHIFT, ED_PAGE_SIZE, useword, 0);
                        ne2000_readmem(nict, nich, asict, asich,
                            x << ED_PAGE_SHIFT, tbuf, ED_PAGE_SIZE, useword);
                        if (memcmp(pbuf0, tbuf, ED_PAGE_SIZE) == 0) {
                                for (i = 0; i < ED_PAGE_SIZE; i++)
                                        pbuf[i] = 255 - x;
                                ne2000_writemem(nict, nich, asict, asich,
                                    pbuf, x << ED_PAGE_SHIFT, ED_PAGE_SIZE,
                                    useword, 0);
                                ne2000_readmem(nict, nich, asict, asich,
                                    x << ED_PAGE_SHIFT, tbuf, ED_PAGE_SIZE,
                                    useword);
                                if (memcmp(pbuf, tbuf, ED_PAGE_SIZE) == 0)
                                        memsize += ED_PAGE_SIZE;
                                else
                                        break;
                        } else
                                break;
                }

                printf("%s: RAM start 0x%x, size %d\n",
                    device_xname(dsc->sc_dev), memstart, memsize);
        }
#endif /* GWETHER */
        dsc->mem_start = memstart;

        dsc->mem_size = memsize;

        if (myea == NULL) {
                /* Read the station address. */
                if (nsc->sc_type == NE2000_TYPE_AX88190 ||
                    nsc->sc_type == NE2000_TYPE_AX88790 ||
                    nsc->sc_type == NE2000_TYPE_AX88796) {
                        /* Select page 0 registers. */
                        NIC_BARRIER(nict, nich);
                        bus_space_write_1(nict, nich, ED_P0_CR,
                            ED_CR_RD2 | ED_CR_PAGE_0 | ED_CR_STA);
                        NIC_BARRIER(nict, nich);
                        /* Select word transfer. */
                        bus_space_write_1(nict, nich, ED_P0_DCR,
                            useword ? ED_DCR_WTS : 0);
                        NIC_BARRIER(nict, nich);
                        ne2000_readmem(nict, nich, asict, asich,
                            AX88190_NODEID_OFFSET, dsc->sc_enaddr,
                            ETHER_ADDR_LEN, useword);
                } else {
                        bool ne1000 = (nsc->sc_type == NE2000_TYPE_NE1000);

                        ne2000_readmem(nict, nich, asict, asich, 0, romdata,
                            sizeof(romdata), useword);
                        for (i = 0; i < ETHER_ADDR_LEN; i++)
                                dsc->sc_enaddr[i] =
                                    romdata[i * (ne1000 ? 1 : 2)];
                }
        } else
                memcpy(dsc->sc_enaddr, myea, sizeof(dsc->sc_enaddr));

        /* Clear any pending interrupts that might have occurred above. */
        NIC_BARRIER(nict, nich);
        bus_space_write_1(nict, nich, ED_P0_ISR, 0xff);
        NIC_BARRIER(nict, nich);

        if (dsc->sc_media_init == NULL)
                dsc->sc_media_init = dp8390_media_init;

        if (dp8390_config(dsc)) {
                aprint_error_dev(dsc->sc_dev, "setup failed\n");
                return 1;
        }

        return 0;
}

/*
 * Detect an NE-2000 or compatible.  Returns a model code.
 */
int
ne2000_detect(bus_space_tag_t nict, bus_space_handle_t nich,
    bus_space_tag_t asict, bus_space_handle_t asich)
{
        const uint8_t test_pattern[32] = "THIS is A memory TEST pattern";
        uint8_t test_buffer[32], tmp;
        int i, rv = NE2000_TYPE_UNKNOWN;
        int useword;

        /* Reset the board. */
#ifdef GWETHER
        bus_space_write_1(asict, asich, NE2000_ASIC_RESET, 0);
        ASIC_BARRIER(asict, asich);
        delay(200);
#endif /* GWETHER */
        tmp = bus_space_read_1(asict, asich, NE2000_ASIC_RESET);
        ASIC_BARRIER(asict, asich);
        delay(10000);

        /*
         * I don't know if this is necessary; probably cruft leftover from
         * Clarkson packet driver code. Doesn't do a thing on the boards I've
         * tested. -DG [note that a outb(0x84, 0) seems to work here, and is
         * non-invasive...but some boards don't seem to reset and I don't have
         * complete documentation on what the 'right' thing to do is...so we do
         * the invasive thing for now.  Yuck.]
         */
        bus_space_write_1(asict, asich, NE2000_ASIC_RESET, tmp);
        ASIC_BARRIER(asict, asich);
        delay(5000);

        /*
         * This is needed because some NE clones apparently don't reset the
         * NIC properly (or the NIC chip doesn't reset fully on power-up).
         * XXX - this makes the probe invasive!  Done against my better
         * judgement.  -DLG
         */
        bus_space_write_1(nict, nich, ED_P0_CR,
            ED_CR_RD2 | ED_CR_PAGE_0 | ED_CR_STP);
        NIC_BARRIER(nict, nich);

        delay(5000);

        /*
         * Generic probe routine for testing for the existence of a DS8390.
         * Must be performed after the NIC has just been reset.  This
         * works by looking at certain register values that are guaranteed
         * to be initialized a certain way after power-up or reset.
         *
         * Specifically:
         *
         *      Register                reset bits      set bits
         *      --------                ----------      --------
         *      CR                      TXP, STA        RD2, STP
         *      ISR                                     RST
         *      IMR                     <all>
         *      DCR                                     LAS
         *      TCR                     LB1, LB0
         *
         * We only look at CR and ISR, however, since looking at the others
         * would require changing register pages, which would be intrusive
         * if this isn't an 8390.
         */

        tmp = bus_space_read_1(nict, nich, ED_P0_CR);
        if ((tmp & (ED_CR_RD2 | ED_CR_TXP | ED_CR_STA | ED_CR_STP)) !=
            (ED_CR_RD2 | ED_CR_STP))
                goto out;

        tmp = bus_space_read_1(nict, nich, ED_P0_ISR);
        if ((tmp & ED_ISR_RST) != ED_ISR_RST)
                goto out;

        bus_space_write_1(nict, nich,
            ED_P0_CR, ED_CR_RD2 | ED_CR_PAGE_0 | ED_CR_STA);
        NIC_BARRIER(nict, nich);

        for (i = 0; i < 100; i++) {
                if ((bus_space_read_1(nict, nich, ED_P0_ISR) & ED_ISR_RST) ==
                    ED_ISR_RST) {
                        /* Ack the reset bit. */
                        bus_space_write_1(nict, nich, ED_P0_ISR, ED_ISR_RST);
                        NIC_BARRIER(nict, nich);
                        break;
                }
                delay(100);
        }

#if 0
        /* XXX */
        if (i == 100)
                goto out;
#endif

        /*
         * Test the ability to read and write to the NIC memory.  This has
         * the side effect of determining if this is an NE1000 or an NE2000.
         */

        /*
         * This prevents packets from being stored in the NIC memory when
         * the readmem routine turns on the start bit in the CR.
         */
        bus_space_write_1(nict, nich, ED_P0_RCR, ED_RCR_MON);
        NIC_BARRIER(nict, nich);

        /* Temporarily initialize DCR for byte operations. */
        bus_space_write_1(nict, nich, ED_P0_DCR, ED_DCR_FT1 | ED_DCR_LS);

        bus_space_write_1(nict, nich, ED_P0_PSTART, 8192 >> ED_PAGE_SHIFT);
        bus_space_write_1(nict, nich, ED_P0_PSTOP, 16384 >> ED_PAGE_SHIFT);

        /*
         * Write a test pattern in byte mode.  If this fails, then there
         * probably isn't any memory at 8k - which likely means that the
         * board is an NE2000.
         */
        ne2000_writemem(nict, nich, asict, asich, test_pattern, 8192,
            sizeof(test_pattern), 0, 1);
        ne2000_readmem(nict, nich, asict, asich, 8192, test_buffer,
            sizeof(test_buffer), 0);

        if (memcmp(test_pattern, test_buffer, sizeof(test_pattern)) == 0) {
                /* We're an NE1000. */
                rv = NE2000_TYPE_NE1000;
                goto out;
        }

        /* not an NE1000 - try NE2000 */

        /* try 16 bit mode first */
        useword = 1;

#ifdef NE2000_DETECT_8BIT
        /*
         * Check bus type in EEPROM first because some NE2000 compatible wedges
         * on 16 bit DMA access if the chip is configured in 8 bit mode.
         */
        if (ne2000_detect_8bit(nict, nich, asict, asich))
                useword = 0;
#endif
 again:
        bus_space_write_1(nict, nich, ED_P0_DCR, ED_DCR_FT1 | ED_DCR_LS |
            (useword ? ED_DCR_WTS : 0));
        bus_space_write_1(nict, nich, ED_P0_PSTART, 16384 >> ED_PAGE_SHIFT);
        bus_space_write_1(nict, nich, ED_P0_PSTOP,
            (16384 + (useword ? 16384 : 8192)) >> ED_PAGE_SHIFT);

        /*
         * Write the test pattern in word mode.  If this also fails,
         * then we don't know what this board is.
         */
        ne2000_writemem(nict, nich, asict, asich, test_pattern, 16384,
            sizeof(test_pattern), useword, 1);
        ne2000_readmem(nict, nich, asict, asich, 16384, test_buffer,
            sizeof(test_buffer), useword);

        if (memcmp(test_pattern, test_buffer, sizeof(test_pattern)) != 0) {
                if (useword == 1) {
                        /* try 8 bit mode */
                        useword = 0;
                        goto again;
                }
                return NE2000_TYPE_UNKNOWN;     /* not an NE2000 either */
        }

        rv = NE2000_TYPE_NE2000;

#if NRTL80X9 > 0
        /* Check for a Realtek RTL8019. */
        if (bus_space_read_1(nict, nich, NERTL_RTL0_8019ID0) == RTL0_8019ID0 &&
            bus_space_read_1(nict, nich, NERTL_RTL0_8019ID1) == RTL0_8019ID1)
                rv = NE2000_TYPE_RTL8019;
#endif

 out:
        /* Clear any pending interrupts that might have occurred above. */
        NIC_BARRIER(nict, nich);
        bus_space_write_1(nict, nich, ED_P0_ISR, 0xff);

        return rv;
}

#ifdef NE2000_DETECT_8BIT
static bool
ne2000_detect_8bit(bus_space_tag_t nict, bus_space_handle_t nich,
    bus_space_tag_t asict, bus_space_handle_t asich)
{
        bool is8bit;
        uint8_t romdata[32];

        is8bit = false;

        /* Set DCR for 8 bit DMA. */
        bus_space_write_1(nict, nich, ED_P0_DCR, ED_DCR_FT1 | ED_DCR_LS);
        /* Read PROM area. */
        ne2000_readmem(nict, nich, asict, asich, 0, romdata,
            sizeof(romdata), 0);
        if (romdata[28] == 'B' && romdata[30] == 'B') {
                /* 'B' (0x42) in 8 bit mode, 'W' (0x57) in 16 bit mode */
                is8bit = true;
        } 
        if (!is8bit) {
                /* not in 8 bit mode; put back DCR setting for 16 bit DMA */
                bus_space_write_1(nict, nich, ED_P0_DCR,
                    ED_DCR_FT1 | ED_DCR_LS | ED_DCR_WTS);
        }

        return is8bit;
}
#endif

/*
 * Write an mbuf chain to the destination NIC memory address using programmed
 * I/O.
 */
int
ne2000_write_mbuf(struct dp8390_softc *sc, struct mbuf *m, int buf)
{
        struct ne2000_softc *nsc = (struct ne2000_softc *)sc;
        bus_space_tag_t nict = sc->sc_regt;
        bus_space_handle_t nich = sc->sc_regh;
        bus_space_tag_t asict = nsc->sc_asict;
        bus_space_handle_t asich = nsc->sc_asich;
        int savelen, padlen;
        int maxwait = 100;      /* about 120us */

        savelen = m->m_pkthdr.len;
        if (savelen < ETHER_MIN_LEN - ETHER_CRC_LEN) {
                padlen = ETHER_MIN_LEN - ETHER_CRC_LEN - savelen;
                savelen = ETHER_MIN_LEN - ETHER_CRC_LEN;
        } else
                padlen = 0;


        /* Select page 0 registers. */
        NIC_BARRIER(nict, nich);
        bus_space_write_1(nict, nich, ED_P0_CR,
            ED_CR_RD2 | ED_CR_PAGE_0 | ED_CR_STA);
        NIC_BARRIER(nict, nich);

        /* Reset remote DMA complete flag. */
        bus_space_write_1(nict, nich, ED_P0_ISR, ED_ISR_RDC);
        NIC_BARRIER(nict, nich);

        /* Set up DMA byte count. */
        bus_space_write_1(nict, nich, ED_P0_RBCR0, savelen);
        bus_space_write_1(nict, nich, ED_P0_RBCR1, savelen >> 8);

        /* Set up destination address in NIC mem. */
        bus_space_write_1(nict, nich, ED_P0_RSAR0, buf);
        bus_space_write_1(nict, nich, ED_P0_RSAR1, buf >> 8);

        /* Set remote DMA write. */
        NIC_BARRIER(nict, nich);
        bus_space_write_1(nict, nich,
            ED_P0_CR, ED_CR_RD1 | ED_CR_PAGE_0 | ED_CR_STA);
        NIC_BARRIER(nict, nich);

        /*
         * Transfer the mbuf chain to the NIC memory.  NE2000 cards
         * require that data be transferred as words, and only words,
         * so that case requires some extra code to patch over odd-length
         * mbufs.
         */
        if (nsc->sc_useword == 0) {
                /* byte ops are easy. */
                for (; m != NULL; m = m->m_next) {
                        if (m->m_len) {
                                bus_space_write_multi_1(asict, asich,
                                    NE2000_ASIC_DATA, mtod(m, uint8_t *),
                                    m->m_len);
                        }
                }
                if (padlen) {
                        for(; padlen > 0; padlen--)
                                bus_space_write_1(asict, asich,
                                    NE2000_ASIC_DATA, 0);
                }
        } else {
                /* word ops are a bit trickier. */
                uint8_t *data, savebyte[2];
                int l, leftover;
#ifdef DIAGNOSTIC
                uint8_t *lim;
#endif
                /* Start out with no leftover data. */
                leftover = 0;
                savebyte[0] = savebyte[1] = 0;

                for (; m != NULL; m = m->m_next) {
                        l = m->m_len;
                        if (l == 0)
                                continue;
                        data = mtod(m, uint8_t *);
#ifdef DIAGNOSTIC
                        lim = data + l;
#endif
                        while (l > 0) {
                                if (leftover) {
                                        /*
                                         * Data left over (from mbuf or
                                         * realignment).  Buffer the next
                                         * byte, and write it and the
                                         * leftover data out.
                                         */
                                        savebyte[1] = *data++;
                                        l--;
                                        bus_space_write_stream_2(asict, asich,
                                            NE2000_ASIC_DATA,
                                            *(uint16_t *)savebyte);
                                        leftover = 0;
                                } else if (BUS_SPACE_ALIGNED_POINTER(data,
                                           uint16_t) == 0) {
                                        /*
                                         * Unaligned data; buffer the next
                                         * byte.
                                         */
                                        savebyte[0] = *data++;
                                        l--;
                                        leftover = 1;
                                } else {
                                        /*
                                         * Aligned data; output contiguous
                                         * words as much as we can, then
                                         * buffer the remaining byte, if any.
                                         */
                                        leftover = l & 1;
                                        l &= ~1;
                                        bus_space_write_multi_stream_2(asict,
                                            asich, NE2000_ASIC_DATA,
                                            (uint16_t *)data, l >> 1);
                                        data += l;
                                        if (leftover)
                                                savebyte[0] = *data++;
                                        l = 0;
                                }
                        }
                        if (l < 0)
                                panic("ne2000_write_mbuf: negative len");
#ifdef DIAGNOSTIC
                        if (data != lim)
                                panic("ne2000_write_mbuf: data != lim");
#endif
                }
                if (leftover) {
                        savebyte[1] = 0;
                        bus_space_write_stream_2(asict, asich, NE2000_ASIC_DATA,
                            *(uint16_t *)savebyte);
                }
                if (padlen) {
                        for(; padlen > 1; padlen -= 2)
                                bus_space_write_stream_2(asict, asich,
                                    NE2000_ASIC_DATA, 0);
                }
        }
        NIC_BARRIER(nict, nich);

        /* some AX88796 doesn't seem to have remote DMA complete */
        if (sc->sc_flags & DP8390_NO_REMOTE_DMA_COMPLETE)
                return savelen;

        /*
         * Wait for remote DMA to complete.  This is necessary because on the
         * transmit side, data is handled internally by the NIC in bursts, and
         * we can't start another remote DMA until this one completes.  Not
         * waiting causes really bad things to happen - like the NIC wedging
         * the bus.
         */
        while (((bus_space_read_1(nict, nich, ED_P0_ISR) & ED_ISR_RDC) !=
            ED_ISR_RDC) && --maxwait) {
                (void)bus_space_read_1(nict, nich, ED_P0_CRDA1);
                (void)bus_space_read_1(nict, nich, ED_P0_CRDA0);
                NIC_BARRIER(nict, nich);
                DELAY(1);
        }

        if (maxwait == 0) {
                log(LOG_WARNING,
                    "%s: remote transmit DMA failed to complete\n",
                    device_xname(sc->sc_dev));
                dp8390_reset(sc);
        }

        return savelen;
}

/*
 * Given a source and destination address, copy 'amount' of a packet from
 * the ring buffer into a linear destination buffer.  Takes into account
 * ring-wrap.
 */
int
ne2000_ring_copy(struct dp8390_softc *sc, int src, void *dstv, u_short amount)
{
        char *dst = dstv;
        struct ne2000_softc *nsc = (struct ne2000_softc *)sc;
        bus_space_tag_t nict = sc->sc_regt;
        bus_space_handle_t nich = sc->sc_regh;
        bus_space_tag_t asict = nsc->sc_asict;
        bus_space_handle_t asich = nsc->sc_asich;
        u_short tmp_amount;
        int useword = nsc->sc_useword;

        /* Does copy wrap to lower addr in ring buffer? */
        if (src + amount > sc->mem_end) {
                tmp_amount = sc->mem_end - src;

                /* Copy amount up to end of NIC memory. */
                ne2000_readmem(nict, nich, asict, asich, src,
                    (uint8_t *)dst, tmp_amount, useword);

                amount -= tmp_amount;
                src = sc->mem_ring;
                dst += tmp_amount;
        }

        ne2000_readmem(nict, nich, asict, asich, src, (uint8_t *)dst,
            amount, useword);

        return src + amount;
}

void
ne2000_read_hdr(struct dp8390_softc *sc, int buf, struct dp8390_ring *hdr)
{
        struct ne2000_softc *nsc = (struct ne2000_softc *)sc;

        ne2000_readmem(sc->sc_regt, sc->sc_regh, nsc->sc_asict, nsc->sc_asich,
            buf, (uint8_t *)hdr, sizeof(struct dp8390_ring),
            nsc->sc_useword);
#if BYTE_ORDER == BIG_ENDIAN
        hdr->count = bswap16(hdr->count);
#endif
}

int
ne2000_test_mem(struct dp8390_softc *sc)
{

        /* Noop. */
        return 0;
}

/*
 * Given a NIC memory source address and a host memory destination address,
 * copy 'amount' from NIC to host using programmed i/o.  The 'amount' is
 * rounded up to a word - ok as long as mbufs are word sized.
 */
void
ne2000_readmem(bus_space_tag_t nict, bus_space_handle_t nich,
    bus_space_tag_t asict, bus_space_handle_t asich,
    int src, uint8_t *dst, size_t amount, int useword)
{

        /* Select page 0 registers. */
        NIC_BARRIER(nict, nich);
        bus_space_write_1(nict, nich, ED_P0_CR,
            ED_CR_RD2 | ED_CR_PAGE_0 | ED_CR_STA);
        NIC_BARRIER(nict, nich);

        /* Round up to a word. */
        amount = roundup2(amount, sizeof(uint16_t));

        /* Set up DMA byte count. */
        bus_space_write_1(nict, nich, ED_P0_RBCR0, amount);
        bus_space_write_1(nict, nich, ED_P0_RBCR1, amount >> 8);

        /* Set up source address in NIC mem. */
        bus_space_write_1(nict, nich, ED_P0_RSAR0, src);
        bus_space_write_1(nict, nich, ED_P0_RSAR1, src >> 8);

        NIC_BARRIER(nict, nich);
        bus_space_write_1(nict, nich, ED_P0_CR,
            ED_CR_RD0 | ED_CR_PAGE_0 | ED_CR_STA);

        ASIC_BARRIER(asict, asich);
        if (useword)
                bus_space_read_multi_stream_2(asict, asich, NE2000_ASIC_DATA,
                    (uint16_t *)dst, amount >> 1);
        else
                bus_space_read_multi_1(asict, asich, NE2000_ASIC_DATA,
                    dst, amount);
}

/*
 * Stripped down routine for writing a linear buffer to NIC memory.  Only
 * used in the probe routine to test the memory.  'len' must be even.
 */
void
ne2000_writemem(bus_space_tag_t nict, bus_space_handle_t nich,
    bus_space_tag_t asict, bus_space_handle_t asich,
    const uint8_t *src, int dst, size_t len, int useword, int quiet)
{
        int maxwait = 100;      /* about 120us */

        /* Select page 0 registers. */
        NIC_BARRIER(nict, nich);
        bus_space_write_1(nict, nich, ED_P0_CR,
            ED_CR_RD2 | ED_CR_PAGE_0 | ED_CR_STA);
        NIC_BARRIER(nict, nich);

        /* Reset remote DMA complete flag. */
        bus_space_write_1(nict, nich, ED_P0_ISR, ED_ISR_RDC);
        NIC_BARRIER(nict, nich);

        /* Set up DMA byte count. */
        bus_space_write_1(nict, nich, ED_P0_RBCR0, len);
        bus_space_write_1(nict, nich, ED_P0_RBCR1, len >> 8);

        /* Set up destination address in NIC mem. */
        bus_space_write_1(nict, nich, ED_P0_RSAR0, dst);
        bus_space_write_1(nict, nich, ED_P0_RSAR1, dst >> 8);

        /* Set remote DMA write. */
        NIC_BARRIER(nict, nich);
        bus_space_write_1(nict, nich, ED_P0_CR,
            ED_CR_RD1 | ED_CR_PAGE_0 | ED_CR_STA);
        NIC_BARRIER(nict, nich);

        ASIC_BARRIER(asict, asich);
        if (useword)
                bus_space_write_multi_stream_2(asict, asich, NE2000_ASIC_DATA,
                    (const uint16_t *)src, len >> 1);
        else
                bus_space_write_multi_1(asict, asich, NE2000_ASIC_DATA,
                    src, len);
        ASIC_BARRIER(asict, asich);

        /*
         * Wait for remote DMA to complete.  This is necessary because on the
         * transmit side, data is handled internally by the NIC in bursts, and
         * we can't start another remote DMA until this one completes.  Not
         * waiting causes really bad things to happen - like the NIC wedging
         * the bus.
         */
        while (((bus_space_read_1(nict, nich, ED_P0_ISR) & ED_ISR_RDC) !=
            ED_ISR_RDC) && --maxwait)
                DELAY(1);

        if (!quiet && maxwait == 0)
                printf("ne2000_writemem: failed to complete\n");
}

int
ne2000_detach(struct ne2000_softc *sc, int flags)
{

        return dp8390_detach(&sc->sc_dp8390, flags);
}

bool
ne2000_suspend(device_t self, const pmf_qual_t *qual)
{
        struct ne2000_softc *sc = device_private(self);
        struct dp8390_softc *dsc = &sc->sc_dp8390;
        int s;

        s = splnet();

        dp8390_stop(dsc);
        dp8390_disable(dsc);

        splx(s);
        return true;
}

bool
ne2000_resume(device_t self, const pmf_qual_t *qual)
{
        struct ne2000_softc *sc = device_private(self);
        struct dp8390_softc *dsc = &sc->sc_dp8390;
        struct ifnet *ifp = &dsc->sc_ec.ec_if;
        int s;

        s = splnet();

        if (ifp->if_flags & IFF_UP) {
                if (dp8390_enable(dsc) == 0)
                        dp8390_init(dsc);
        }

        splx(s);
        return true;
}