/*      $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;
       }
}