/*      $NetBSD: mx98905.c,v 1.18 2024/05/21 07:29:40 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.
 */

/*
 * Special routines for the Macronix MX 98905.  For use with the "ne" driver.
 */

/*
 * <URL:http://mail-index.NetBSD.org/port-arm32/1996/06/23/0005.html>:
 * There are 2 types of etherh card.  One uses the macronics chipset MX98905
 * and that chipset has a bug in it, in that it the MSB remote DMA
 * register does not work.  There is a workaround for this which
 * should be around soon.  In fact, I think only the buffer ram test
 * ever transfers more than 256 bytes across the DMA channel, so disabling
 * it will make the mx stuff work.
 */

#include <sys/param.h>

__KERNEL_RCSID(0, "$NetBSD: mx98905.c,v 1.18 2024/05/21 07:29:40 andvar Exp $");

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

#include <net/if.h>
#include <net/if_ether.h>
#include <net/if_media.h>

#include <sys/bus.h>

#include <dev/ic/dp8390reg.h>
#include <dev/ic/dp8390var.h>
#include <dev/ic/ne2000reg.h>
#include <dev/ic/ne2000var.h>
#include <dev/ic/mx98905var.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 */

static inline void mx98905_write_setup(struct dp8390_softc *, int, int);
static inline void mx98905_write_wait(struct dp8390_softc *);

void
mx98905_attach(struct dp8390_softc *sc)
{

        sc->ring_copy = mx98905_ring_copy;
        sc->write_mbuf = mx98905_write_mbuf;
        sc->read_hdr = mx98905_read_hdr;
}

static inline void
mx98905_write_setup(struct dp8390_softc *sc, int len, int buf)
{
        bus_space_tag_t nict = sc->sc_regt;
        bus_space_handle_t nich = sc->sc_regh;

        /* 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, 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);
}


static inline void
mx98905_write_wait(struct dp8390_softc *sc)
{
        int maxwait = 100;      /* about 120us */
        bus_space_tag_t nict = sc->sc_regt;
        bus_space_handle_t nich = sc->sc_regh;

        /*
         * 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) {
                bus_space_read_1(nict, nich, ED_P0_CRDA1);
                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);
        }
}

/*
 * Write an mbuf chain to the destination NIC memory address using programmed
 * I/O.
 */
int
mx98905_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, dmalen, resid, len;
        u_int8_t *data, savebyte[2];
        int l, leftover;
#ifdef DIAGNOSTIC
        u_int8_t *lim;
#endif
        int i;

        resid = savelen = m->m_pkthdr.len;

        dmalen = uimin(resid, 254);

        mx98905_write_setup(sc, dmalen, buf);

        buf += dmalen;
        resid -= dmalen;

        /*
         * 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.
         */
        /* NE2000s are a bit trickier. */
        /* Start out with no leftover data. */
        leftover = 0;
        savebyte[0] = savebyte[1] = 0;

        for (; m != 0; m = m->m_next) {
                l = m->m_len;
                if (l == 0)
                        continue;
                data = mtod(m, u_int8_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, *(u_int16_t *)savebyte);
                                dmalen -= 2;
                                leftover = 0;
                        } else if (BUS_SPACE_ALIGNED_POINTER(data,
                            u_int16_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.
                                 */
                                len = uimin(l, dmalen);
                                leftover = len & 1;
                                len &= ~1;
                                bus_space_write_multi_stream_2(asict,
                                    asich, NE2000_ASIC_DATA,
                                    (u_int16_t *)data, len >> 1);
                                dmalen -= len;
                                data += len;
                                if (leftover)
                                        savebyte[0] = *data++;
                                l -= len + leftover;
                        }
                        if (dmalen == 0 && resid > 0) {
                                mx98905_write_wait(sc);
                                dmalen = uimin(resid, 254);

                                mx98905_write_setup(sc, dmalen, buf);

                                buf += dmalen;
                                resid -= dmalen;
                        }
                }
                if (l < 0)
                        panic("mx98905_write_mbuf: negative len");
#ifdef DIAGNOSTIC
                if (data != lim)
                        panic("mx98905_write_mbuf: data != lim");
#endif
        }
        if (leftover) {
                savebyte[1] = 0;
                bus_space_write_stream_2(asict, asich, NE2000_ASIC_DATA,
                    *(u_int16_t *)savebyte);
        }
        if (savelen < ETHER_MIN_LEN - ETHER_CRC_LEN) {
                for(i = 0; i < (ETHER_MIN_LEN - ETHER_CRC_LEN - savelen) >> 1;
                    i++)
                        bus_space_write_stream_2(asict, asich,
                            NE2000_ASIC_DATA, 0);
                savelen = ETHER_MIN_LEN - ETHER_CRC_LEN;
        }
        NIC_BARRIER(nict, nich);

        mx98905_write_wait(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
mx98905_ring_copy(struct dp8390_softc *sc, int src, void *vdst, u_short amount)
{
        struct ne2000_softc *nsc = (struct ne2000_softc *)sc;
        uint8_t *dst = vdst;
        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. */
                mx98905_readmem(nict, nich, asict, asich, src,
                    (u_int8_t *)dst, tmp_amount, useword);

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

        mx98905_readmem(nict, nich, asict, asich, src, dst, amount, useword);

        return (src + amount);
}

void
mx98905_read_hdr(struct dp8390_softc *sc, int buf, struct dp8390_ring *hdr)
{
        struct ne2000_softc *nsc = (struct ne2000_softc *)sc;

        mx98905_readmem(sc->sc_regt, sc->sc_regh, nsc->sc_asict, nsc->sc_asich,
            buf, (u_int8_t *)hdr, sizeof(struct dp8390_ring),
            nsc->sc_useword);
#if BYTE_ORDER == BIG_ENDIAN
        hdr->count = bswap16(hdr->count);
#endif
}

static inline void
mx98905_read_setup(bus_space_tag_t nict, bus_space_handle_t nich,
    int len, int buf)
{

        /* 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);

        /* 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 source 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);

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

        bus_space_barrier(nict, nich, 0, NE2000_NPORTS,
                          BUS_SPACE_BARRIER_READ | BUS_SPACE_BARRIER_WRITE);
}

/*
 * 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
mx98905_readmem(bus_space_tag_t nict, bus_space_handle_t nich, bus_space_tag_t asict, bus_space_handle_t asich, int src, u_int8_t *dst, size_t amount, int useword)
{
        int len, resid;

        resid = amount;
        /* Round up to a word. */
        if (resid & 1)
                ++resid;

        while (resid > 0) {
                len = uimin(resid, 254);
                mx98905_read_setup(nict, nich, len, src);
                if (useword)
                        bus_space_read_multi_stream_2(asict, asich,
                            NE2000_ASIC_DATA, (u_int16_t *)dst, len >> 1);
                else
                        bus_space_read_multi_1(asict, asich, NE2000_ASIC_DATA,
                            dst, len);
                resid -= len;
                src += len;
                dst += len;
        }
}