/*      $NetBSD: zs.c,v 1.64 2026/02/17 22:26:51 andvar Exp $   */

/*
 * Copyright (c) 1996-1998 Bill Studenmund
 * Copyright (c) 1995 Gordon W. Ross
 * All rights reserved.
 *
 * 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 AUTHOR ``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 AUTHOR 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.
 */

/*
 * Zilog Z8530 Dual UART driver (machine-dependent part)
 *
 * Runs two serial lines per chip using slave drivers.
 * Plain tty/async lines use the zs_async slave.
 * Sun keyboard/mouse uses the zs_kbd/zs_ms slaves.
 * Other ports use their own mice & keyboard slaves.
 *
 * Credits & history:
 *
 * With NetBSD 1.1, port-mac68k started using a port of the port-sparc
 * (port-sun3?) zs.c driver (which was in turn based on code in the
 * Berkeley 4.4 Lite release). Bill Studenmund did the port, with
 * help from Allen Briggs and Gordon Ross <gwr@NetBSD.org>. Noud de
 * Brouwer field-tested the driver at a local ISP.
 *
 * Bill Studenmund and Gordon Ross then ported the machine-independent
 * z8530 driver to work with port-mac68k. NetBSD 1.2 contained an
 * intermediate version (mac68k using a local, patched version of
 * the m.i. drivers), with NetBSD 1.3 containing a full version.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: zs.c,v 1.64 2026/02/17 22:26:51 andvar Exp $");

#include "opt_ddb.h"
#include "opt_mac68k.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/device.h>
#include <sys/conf.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/tty.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/cpu.h>
#include <sys/intr.h>

#include <machine/autoconf.h>
#include <machine/psc.h>
#include <machine/viareg.h>

#include <dev/cons.h>
#include <dev/ic/z8530reg.h>
#include <machine/z8530var.h>
#include <mac68k/dev/zs_cons.h>

/* Are these in a header file anywhere? */
/* Booter flags interface */
#define ZSMAC_RAW       0x01
#define ZSMAC_LOCALTALK 0x02

#define PCLK    (9600 * 384)

/*
 * Some warts needed by z8530tty.c -
 */
int zs_def_cflag = (CREAD | CS8 | HUPCL);

/*
 * abort detection on console will now timeout after iterating on a loop
 * the following # of times. Cheep hack. Also, abort detection is turned
 * off after a timeout (i.e. maybe there's not a terminal hooked up).
 */
#define ZSABORT_DELAY 3000000

/*
 * Define interrupt levels.
 */
#define ZSHARD_PRI      4       /* Wired on the CPU board... */
/*
 * Serial port cards with zs chips on them are actually at the
 * NuBus interrupt level, which is lower than 4. But blocking
 * level 4 interrupts will block those interrupts too, so level
 * 4 is fine.
 */

/* The layout of this is hardware-dependent (padding, order). */
struct zschan {
        volatile uint8_t zc_csr;        /* ctrl,status, and indirect access */
        uint8_t         zc_xxx0;
        uint8_t         zc_xxx1;        /* part of the other channel lives here! */
        uint8_t         zc_xxx2;        /* Yea Apple! */
        volatile uint8_t zc_data;       /* data */
        uint8_t         zc_xxx3;
        uint8_t         zc_xxx4;
        uint8_t         zc_xxx5;
};

/* Flags from cninit() */
static int zs_hwflags[2];
/* Default speed for each channel */
static int zs_defspeed[2] = {
        9600,           /* tty00 */
        9600,           /* tty01 */
};
/* console stuff */
void    *zs_conschan;
int     zs_consunit;
#ifdef  ZS_CONSOLE_ABORT
int     zs_cons_canabort = 1;
#else
int     zs_cons_canabort = 0;
#endif /* ZS_CONSOLE_ABORT*/
/* device to which the console is attached--if serial. */
dev_t   mac68k_zsdev;
/* Mac stuff */
extern volatile unsigned char *sccA;

int     zs_cn_check_speed(int);

/*
 * Even though zsparam will set up the clock multiples, etc., we
 * still set them here as: 1) mice & keyboards don't use zsparam,
 * and 2) the console stuff uses these defaults before device
 * attach.
 */

static uint8_t zs_init_reg[16] = {
        0,      /* 0: CMD (reset, etc.) */
        0,      /* 1: No interrupts yet. */
        0x18 + ZSHARD_PRI,      /* IVECT */
        ZSWR3_RX_8 | ZSWR3_RX_ENABLE,
        ZSWR4_CLK_X16 | ZSWR4_ONESB | ZSWR4_EVENP,
        ZSWR5_TX_8 | ZSWR5_TX_ENABLE,
        0,      /* 6: TXSYNC/SYNCLO */
        0,      /* 7: RXSYNC/SYNCHI */
        0,      /* 8: alias for data port */
        ZSWR9_MASTER_IE,
        0,      /*10: Misc. TX/RX control bits */
        ZSWR11_TXCLK_BAUD | ZSWR11_RXCLK_BAUD,
        ((PCLK/32)/9600)-2,     /*12: BAUDLO (default=9600) */
        0,                      /*13: BAUDHI (default=9600) */
        ZSWR14_BAUD_ENA,
        ZSWR15_BREAK_IE,
};

struct zschan *
zs_get_chan_addr(int channel)
{
        char *addr;
        struct zschan *zc;

        addr = (char *)__UNVOLATILE(sccA);
        if (channel == 0) {
                zc = (struct zschan *)(addr + 2);
                /* handle the fact the ports are intertwined. */
        } else {
                zc = (struct zschan *)(addr);
        }
        return (zc);
}


/* Find PROM mappings (for console support). */
int zsinited = 0; /* 0 = not, 1 = inited, not attached, 2= attached */

void
zs_init(void)
{
        zsinited = 1;
        if (zs_conschan != 0){ /* we might have moved io under the console */
                zs_conschan = zs_get_chan_addr(zs_consunit);
                /* so recalc the console port */
        }
}       


/****************************************************************
 * Autoconfig
 ****************************************************************/

/* Definition of the driver for autoconfig. */
static int      zsc_match(device_t, cfdata_t, void *);
static void     zsc_attach(device_t, device_t, void *);
static int      zsc_print(void *, const char *);

CFATTACH_DECL_NEW(zsc, sizeof(struct zsc_softc),
    zsc_match, zsc_attach, NULL, NULL);

extern struct cfdriver zsc_cd;

int zshard(void *);

/*
 * Is the zs chip present?
 */
static int
zsc_match(device_t parent, cfdata_t cf, void *aux)
{
        if (zsinited == 2)
                return 0;

        return 1;
}

/*
 * Attach a found zs.
 *
 * Match slave number to zs unit number, so that misconfiguration will
 * not set up the keyboard as ttya, etc.
 */
static void
zsc_attach(device_t parent, device_t self, void *aux)
{
        struct zsc_softc *zsc = device_private(self);
        struct zsc_attach_args zsc_args;
        volatile struct zschan *zc;
        struct xzs_chanstate *xcs;
        struct zs_chanstate *cs;
        int s, chip, theflags, channel;

        zsc->zsc_dev = self;
        if (!zsinited)
                zs_init();
        zsinited = 2;

        chip = 0; /* We'll deal with chip types post 1.2 */
        aprint_normal(" chip type %d \n",chip);

        /*
         * Initialize software state for each channel.
         */
        for (channel = 0; channel < 2; channel++) {
                zsc_args.channel = channel;
                zsc_args.hwflags = zs_hwflags[channel];
                xcs = &zsc->xzsc_xcs_store[channel];
                cs  = &xcs->xzs_cs;
                zsc->zsc_cs[channel] = cs;

                zs_lock_init(cs);
                cs->cs_channel = channel;
                cs->cs_private = NULL;
                cs->cs_ops = &zsops_null;

                zc = zs_get_chan_addr(channel);
                cs->cs_reg_csr  = &zc->zc_csr;
                cs->cs_reg_data = &zc->zc_data;

                memcpy(cs->cs_creg, zs_init_reg, 16);
                memcpy(cs->cs_preg, zs_init_reg, 16);

                /* Current BAUD rate generator clock. */
                cs->cs_brg_clk = PCLK / 16;     /* RTxC is 230400*16, so use 230400 */
                cs->cs_defspeed = zs_defspeed[channel];
                cs->cs_defcflag = zs_def_cflag;

                /* Make these correspond to cs_defcflag (-crtscts) */
                cs->cs_rr0_dcd = ZSRR0_DCD;
                cs->cs_rr0_cts = 0;
                cs->cs_wr5_dtr = ZSWR5_DTR;
                cs->cs_wr5_rts = 0;

#ifdef __notyet__
                cs->cs_slave_type = ZS_SLAVE_NONE;
#endif

                /* Define BAUD rate stuff. */
                xcs->cs_clocks[0].clk = PCLK;
                xcs->cs_clocks[0].flags = ZSC_RTXBRG | ZSC_RTXDIV;
                xcs->cs_clocks[1].flags =
                        ZSC_RTXBRG | ZSC_RTXDIV | ZSC_VARIABLE | ZSC_EXTERN;
                xcs->cs_clocks[2].flags = ZSC_TRXDIV | ZSC_VARIABLE;
                xcs->cs_clock_count = 3;
                if (channel == 0) {
                        theflags = mac68k_machine.modem_flags;
                        xcs->cs_clocks[1].clk = mac68k_machine.modem_dcd_clk;
                        xcs->cs_clocks[2].clk = mac68k_machine.modem_cts_clk;
                } else {
                        theflags = mac68k_machine.print_flags;
                        xcs->cs_clocks[1].flags = ZSC_VARIABLE;
                        /*
                         * Yes, we aren't defining ANY clock source enables for the
                         * printer's DCD clock in. The hardware won't let us
                         * use it. But a clock will freak out the chip, so we
                         * let you set it, telling us to bar interrupts on the line.
                         */
                        xcs->cs_clocks[1].clk = mac68k_machine.print_dcd_clk;
                        xcs->cs_clocks[2].clk = mac68k_machine.print_cts_clk;
                }
                if (xcs->cs_clocks[1].clk)
                        zsc_args.hwflags |= ZS_HWFLAG_NO_DCD;
                if (xcs->cs_clocks[2].clk)
                        zsc_args.hwflags |= ZS_HWFLAG_NO_CTS;

                printf("zsc%d channel %d: d_speed %6d DCD clk %ld CTS clk %ld",
                                device_unit(self), channel, cs->cs_defspeed,
                                xcs->cs_clocks[1].clk, xcs->cs_clocks[2].clk);

                /* Set defaults in our "extended" chanstate. */
                xcs->cs_csource = 0;
                xcs->cs_psource = 0;
                xcs->cs_cclk_flag = 0;  /* Nothing fancy by default */
                xcs->cs_pclk_flag = 0;

                if (theflags & ZSMAC_RAW) {
                        zsc_args.hwflags |= ZS_HWFLAG_RAW;
                        printf(" (raw defaults)");
                }

                /*
                 * XXX - This might be better done with a "stub" driver
                 * (to replace zstty) that ignores LocalTalk for now.
                 */
                if (theflags & ZSMAC_LOCALTALK) {
                        printf(" shielding from LocalTalk");
                        cs->cs_defspeed = 1;
                        cs->cs_creg[ZSRR_BAUDLO] = cs->cs_preg[ZSRR_BAUDLO] = 0xff;
                        cs->cs_creg[ZSRR_BAUDHI] = cs->cs_preg[ZSRR_BAUDHI] = 0xff;
                        zs_write_reg(cs, ZSRR_BAUDLO, 0xff);
                        zs_write_reg(cs, ZSRR_BAUDHI, 0xff);
                        /*
                         * If we might have LocalTalk, then make sure we have the
                         * Baud rate low-enough to not do any damage.
                         */
                }

                /*
                 * We used to disable chip interrupts here, but we now
                 * do that in zscnprobe, just in case MacOS left the chip on.
                 */

                xcs->cs_chip = chip;

                /* Stash away a copy of the final H/W flags. */
                xcs->cs_hwflags = zsc_args.hwflags;

                printf("\n");

                /*
                 * Look for a child driver for this channel.
                 * The child attach will setup the hardware.
                 */
                if (!config_found(self, (void *)&zsc_args, zsc_print,
                    CFARGS_NONE)) {
                        /* No sub-driver.  Just reset it. */
                        uint8_t reset = (channel == 0) ?
                                ZSWR9_A_RESET : ZSWR9_B_RESET;
                        s = splzs();
                        zs_write_reg(cs,  9, reset);
                        splx(s);
                }
        }

        if (current_mac_model->class == MACH_CLASSAV) {
                add_psc_lev4_intr(PSCINTR_SCCA, zshard, zsc);
                add_psc_lev4_intr(PSCINTR_SCCB, zshard, zsc);
        } else {
                intr_establish(zshard, zsc, ZSHARD_PRI);
        }
        zsc->zsc_softintr_cookie = softint_establish(SOFTINT_SERIAL,
            (void (*)(void *))zsc_intr_soft, zsc);

        /* Now safe to enable interrupts. */

        /*
         * Set the master interrupt enable and interrupt vector.
         * (common to both channels, do it on A)
         */
        cs = zsc->zsc_cs[0];
        s = splzs();
        /* interrupt vector */
        zs_write_reg(cs, 2, zs_init_reg[2]);
        /* master interrupt control (enable) */
        zs_write_reg(cs, 9, zs_init_reg[9]);
        splx(s);
}

static int
zsc_print(void *aux, const char *name)
{
        struct zsc_attach_args *args = aux;

        if (name != NULL)
                aprint_normal("%s: ", name);

        if (args->channel != -1)
                aprint_normal(" channel %d", args->channel);

        return UNCONF;
}

int
zsmdioctl(struct zs_chanstate *cs, u_long cmd, void *data)
{
        switch (cmd) {
        default:
                return (EPASSTHROUGH);
        }
        return (0);
}

void
zsmd_setclock(struct zs_chanstate *cs)
{
        struct xzs_chanstate *xcs = (void *)cs;

        if (cs->cs_channel != 0)
                return;

        /*
         * If the new clock has the external bit set, then select the
         * external source.
         */
        via_set_modem((xcs->cs_pclk_flag & ZSC_EXTERN) ? 1 : 0);
}

/*
 * Do the minimum work to pull data off of the chip and queue it up
 * for later processing.
 */
int
zshard(void *arg)
{
        struct zsc_softc *zsc = arg;
        int rval;

        if (zsc == NULL)
                return 0;

        rval = zsc_intr_hard(zsc);
        if ((zsc->zsc_cs[0]->cs_softreq) || (zsc->zsc_cs[1]->cs_softreq)) {
                softint_schedule(zsc->zsc_softintr_cookie);
        }
        return (rval);
}

#ifndef ZS_TOLERANCE
#define ZS_TOLERANCE 51
/* 5% in tenths of a %, plus 1 so that exactly 5% will be ok. */
#endif

/*
 * check out a rate for acceptability from the internal clock
 * source. Used in console config to validate a requested
 * default speed. Placed here so that all the speed checking code is
 * in one place.
 *
 * != 0 means ok.
 */
int
zs_cn_check_speed(int bps)
{
        int tc, rate;

        tc = BPS_TO_TCONST(PCLK / 16, bps);
        if (tc < 0)
                return 0;
        rate = TCONST_TO_BPS(PCLK / 16, tc);
        if (ZS_TOLERANCE > abs(((rate - bps)*1000)/bps)) 
                return 1;
        else
                return 0;
}

/*
 * Search through the signal sources in the channel, and
 * pick the best one for the baud rate requested. Return
 * a -1 if not achievable in tolerance. Otherwise return 0
 * and fill in the values.
 *
 * This routine draws inspiration from the Atari port's zs.c
 * driver in NetBSD 1.1 which did the same type of source switching.
 * Tolerance code inspired by comspeed routine in isa/com.c.
 *
 * By Bill Studenmund, 1996-05-12
 */
int
zs_set_speed(struct zs_chanstate *cs, int bps)
{
        struct xzs_chanstate *xcs = (void *) cs;
        int i, tc, tc0 = 0, tc1, s, sf = 0;
        int src, rate0, rate1, err, tol;

        if (bps == 0)
                return (0);

        src = -1;               /* no valid source yet */
        tol = ZS_TOLERANCE;

        /*
         * Step through all the sources and see which one matches
         * the best. A source has to match BETTER than tol to be chosen.
         * Thus if two sources give the same error, the first one will be
         * chosen. Also, allow for the possibility that one source might run
         * both the BRG and the direct divider (i.e. RTxC).
         */
        for (i=0; i < xcs->cs_clock_count; i++) {
                if (xcs->cs_clocks[i].clk <= 0)
                        continue;       /* skip non-existent or bad clocks */
                if (xcs->cs_clocks[i].flags & ZSC_BRG) {
                        /* check out BRG at /16 */
                        tc1 = BPS_TO_TCONST(xcs->cs_clocks[i].clk >> 4, bps);
                        if (tc1 >= 0) {
                                rate1 = TCONST_TO_BPS(xcs->cs_clocks[i].clk >> 4, tc1);
                                err = abs(((rate1 - bps)*1000)/bps);
                                if (err < tol) {
                                        tol = err;
                                        src = i;
                                        sf = xcs->cs_clocks[i].flags & ~ZSC_DIV;
                                        tc0 = tc1;
                                        rate0 = rate1;
                                }
                        }
                }
                if (xcs->cs_clocks[i].flags & ZSC_DIV) {
                        /*
                         * Check out either /1, /16, /32, or /64
                         * Note: for /1, you'd better be using a synchronized
                         * clock!
                         */
                        int b0 = xcs->cs_clocks[i].clk, e0 = abs(b0-bps);
                        int b1 = b0 >> 4, e1 = abs(b1-bps);
                        int b2 = b1 >> 1, e2 = abs(b2-bps);
                        int b3 = b2 >> 1, e3 = abs(b3-bps);

                        if (e0 < e1 && e0 < e2 && e0 < e3) {
                                err = e0;
                                rate1 = b0;
                                tc1 = ZSWR4_CLK_X1;
                        } else if (e0 > e1 && e1 < e2  && e1 < e3) {
                                err = e1;
                                rate1 = b1;
                                tc1 = ZSWR4_CLK_X16;
                        } else if (e0 > e2 && e1 > e2 && e2 < e3) {
                                err = e2;
                                rate1 = b2;
                                tc1 = ZSWR4_CLK_X32;
                        } else {
                                err = e3;
                                rate1 = b3;
                                tc1 = ZSWR4_CLK_X64;
                        }

                        err = (err * 1000)/bps;
                        if (err < tol) {
                                tol = err;
                                src = i;
                                sf = xcs->cs_clocks[i].flags & ~ZSC_BRG;
                                tc0 = tc1;
                                rate0 = rate1;
                        }
                }
        }
#ifdef ZSMACDEBUG
        printf("Checking for rate %d. Found source #%d.\n", bps, src);
#endif
        if (src == -1)
                return (EINVAL); /* no can do */

        /*
         * The M.I. layer likes to keep cs_brg_clk current, even though
         * we are the only ones who should be touching the BRG's rate.
         *
         * Note: we are assuming that any ZSC_EXTERN signal source comes in
         * on the RTxC pin. Correct for the mac68k obio zsc.
         */
        if (sf & ZSC_EXTERN)
                cs->cs_brg_clk = xcs->cs_clocks[i].clk >> 4;
        else
                cs->cs_brg_clk = PCLK / 16;

        /*
         * Now we have a source, so set it up.
         */
        s = splzs();
        xcs->cs_psource = src;
        xcs->cs_pclk_flag = sf;
        bps = rate0;
        if (sf & ZSC_BRG) {
                cs->cs_preg[4] = ZSWR4_CLK_X16;
                cs->cs_preg[11]= ZSWR11_RXCLK_BAUD | ZSWR11_TXCLK_BAUD;
                if (sf & ZSC_PCLK) {
                        cs->cs_preg[14] = ZSWR14_BAUD_ENA | ZSWR14_BAUD_FROM_PCLK;
                } else {
                        cs->cs_preg[14] = ZSWR14_BAUD_ENA;
                }
                tc = tc0;
        } else {
                cs->cs_preg[4] = tc0;
                if (sf & ZSC_RTXDIV) {
                        cs->cs_preg[11] = ZSWR11_RXCLK_RTXC | ZSWR11_TXCLK_RTXC;
                } else {
                        cs->cs_preg[11] = ZSWR11_RXCLK_TRXC | ZSWR11_TXCLK_TRXC;
                }
                cs->cs_preg[14]= 0;
                tc = 0xffff;
        }
        /* Set the BAUD rate divisor. */
        cs->cs_preg[12] = tc;
        cs->cs_preg[13] = tc >> 8;
        splx(s);
        
#ifdef ZSMACDEBUG
        printf("Rate is %7d, tc is %7d, source no. %2d, flags %4x\n",
            bps, tc, src, sf);
        printf("Registers are: 4 %x, 11 %x, 14 %x\n\n",
            cs->cs_preg[4], cs->cs_preg[11], cs->cs_preg[14]);
#endif

        cs->cs_preg[5] |= ZSWR5_RTS;    /* Make sure the drivers are on! */

        /* Caller will stuff the pending registers. */
        return (0);
}

int
zs_set_modes(struct zs_chanstate *cs, int cflag)
{
        struct xzs_chanstate *xcs = (void*)cs;
        int s;

        /*
         * Make sure we don't enable hfc on a signal line we're ignoring.
         * As we enable CTS interrupts only if we have CRTSCTS or CDTRCTS,
         * this code also effectively turns off ZSWR15_CTS_IE.
         *
         * Also, disable DCD interrupts if we've been told to ignore
         * the DCD pin. Happens on mac68k because the input line for
         * DCD can also be used as a clock input.  (Just set CLOCAL.)
         *
         * If someone tries to turn an invalid flow mode on, Just Say No
         * (Suggested by gwr)
         */
        if ((cflag & CDTRCTS) && (cflag & (CRTSCTS | MDMBUF)))
                return (EINVAL);
        cs->cs_rr0_pps = 0;
        if (xcs->cs_hwflags & ZS_HWFLAG_NO_DCD) {
                if (cflag & MDMBUF)
                        return (EINVAL);
                cflag |= CLOCAL;
        } else {
                /*
                 * cs->cs_rr0_pps indicates which bit MAY be used for pps.
                 * Enable only if nothing else will want the interrupt and
                 * it's ok to enable interrupts on this line.
                 */
                if ((cflag & (CLOCAL | MDMBUF)) == CLOCAL)
                        cs->cs_rr0_pps = ZSRR0_DCD;
        }
        if ((xcs->cs_hwflags & ZS_HWFLAG_NO_CTS) && (cflag & (CRTSCTS | CDTRCTS)))
                return (EINVAL);

        /*
         * Output hardware flow control on the chip is horrendous:
         * if carrier detect drops, the receiver is disabled, and if
         * CTS drops, the transmitter is stopped IN MID CHARACTER!
         * Therefore, NEVER set the HFC bit, and instead use the
         * status interrupt to detect CTS changes.
         */
        s = splzs();
        if ((cflag & (CLOCAL | MDMBUF)) != 0)
                cs->cs_rr0_dcd = 0;
        else
                cs->cs_rr0_dcd = ZSRR0_DCD;
        /*
         * The mac hardware only has one output, DTR (HSKo in Mac
         * parlance). In HFC mode, we use it for the functions
         * typically served by RTS and DTR on other ports, so we
         * have to fake the upper layer out some.
         *
         * CRTSCTS we use CTS as an input which tells us when to shut up.
         * We make no effort to shut up the other side of the connection.
         * DTR is used to hang up the modem.
         *
         * In CDTRCTS, we use CTS to tell us to stop, but we use DTR to
         * shut up the other side.
         */
        if ((cflag & CRTSCTS) != 0) {
                cs->cs_wr5_dtr = ZSWR5_DTR;
                cs->cs_wr5_rts = 0;
                cs->cs_rr0_cts = ZSRR0_CTS;
        } else if ((cflag & CDTRCTS) != 0) {
                cs->cs_wr5_dtr = 0;
                cs->cs_wr5_rts = ZSWR5_DTR;
                cs->cs_rr0_cts = ZSRR0_CTS;
        } else if ((cflag & MDMBUF) != 0) {
                cs->cs_wr5_dtr = 0;
                cs->cs_wr5_rts = ZSWR5_DTR;
                cs->cs_rr0_cts = ZSRR0_DCD;
        } else {
                cs->cs_wr5_dtr = ZSWR5_DTR;
                cs->cs_wr5_rts = 0;
                cs->cs_rr0_cts = 0;
        }
        splx(s);

        /* Caller will stuff the pending registers. */
        return (0);
}


/*
 * Read or write the chip with suitable delays.
 * MacII hardware has the delay built in.
 * No need for extra delay. :-) However, some clock-chirped
 * macs, or zsc's on serial add-on boards might need it.
 */
#define ZS_DELAY()

uint8_t
zs_read_reg(struct zs_chanstate *cs, uint8_t reg)
{
        uint8_t val;

        *cs->cs_reg_csr = reg;
        ZS_DELAY();
        val = *cs->cs_reg_csr;
        ZS_DELAY();
        return val;
}

void
zs_write_reg(struct zs_chanstate *cs, uint8_t reg, uint8_t val)
{
        *cs->cs_reg_csr = reg;
        ZS_DELAY();
        *cs->cs_reg_csr = val;
        ZS_DELAY();
}

uint8_t
zs_read_csr(struct zs_chanstate *cs)
{
        uint8_t val;

        val = *cs->cs_reg_csr;
        ZS_DELAY();
        /* make up for the fact CTS is wired backwards */
        val ^= ZSRR0_CTS;
        return val;
}

void
zs_write_csr(struct zs_chanstate *cs, uint8_t val)
{
        /* Note, the csr does not write CTS... */
        *cs->cs_reg_csr = val;
        ZS_DELAY();
}

uint8_t
zs_read_data(struct zs_chanstate *cs)
{
        uint8_t val;

        val = *cs->cs_reg_data;
        ZS_DELAY();
        return val;
}

void
zs_write_data(struct zs_chanstate *cs, uint8_t val)
{
        *cs->cs_reg_data = val;
        ZS_DELAY();
}

/****************************************************************
 * Console support functions (mac68k specific!)
 * Note: this code is allowed to know about the layout of
 * the chip registers, and uses that to keep things simple.
 * XXX - I think I like the mvme167 code better. -gwr
 * XXX - Well :-P  :-)  -wrs
 ****************************************************************/

#define zscnpollc       nullcnpollc
cons_decl(zs);

static void     zscnsetup(void);

/*
 * Console functions.
 */

/*
 * This code modeled after the zs_setparam routine in zskgdb
 * It sets the console unit to a known state so we can output
 * correctly.
 */
static void
zscnsetup(void)
{
        struct xzs_chanstate xcs;
        struct zs_chanstate *cs;
        struct zschan *zc;
        int tconst, s;

        /* Setup temporary chanstate. */
        memset(&xcs, 0, sizeof(xcs));
        cs = &xcs.xzs_cs;
        zc = zs_conschan;
        cs->cs_reg_csr  = &zc->zc_csr;
        cs->cs_reg_data = &zc->zc_data;
        cs->cs_channel = zs_consunit;
        cs->cs_brg_clk = PCLK / 16;

        memcpy(cs->cs_preg, zs_init_reg, 16);
        cs->cs_preg[5] |= ZSWR5_DTR | ZSWR5_RTS;
        cs->cs_preg[15] = ZSWR15_BREAK_IE;
        tconst = BPS_TO_TCONST(cs->cs_brg_clk, zs_defspeed[zs_consunit]);
        cs->cs_preg[12] = tconst;
        cs->cs_preg[13] = tconst >> 8;
        /* can't use zs_set_speed as we haven't set up the
         * signal sources, and it's not worth it for now 
         */

        /*
         * As zs_loadchannelregs doesn't touch reg 9 (interrupt control),
         * we won't accidentally turn on interrupts below
         */
        s = splhigh();
        zs_loadchannelregs(cs);
        splx(s);
}

/*
 * zscnprobe is the routine which gets called as the kernel is trying to
 * figure out where the console should be. Each io driver which might
 * be the console (as defined in mac68k/conf.c) gets probed. The probe
 * fills in the consdev structure. Important parts are the device #,
 * and the console priority. Values are CN_DEAD (don't touch me),
 * CN_NORMAL (I'm here, but elsewhere might be better), CN_INTERNAL
 * (the video, better than CN_NORMAL), and CN_REMOTE (pick me!)
 *
 * As the mac's a bit different, we do extra work here. We mainly check
 * to see if we have serial echo going on. Also should check for default
 * speeds.
 */
void
zscnprobe(struct consdev * cp)
{
        extern u_long   IOBase;
        int     maj, unit, i;
        extern const struct cdevsw zstty_cdevsw;

        maj = cdevsw_lookup_major(&zstty_cdevsw);
        if (maj != -1) {
                cp->cn_pri = CN_NORMAL;          /* Lower than CN_INTERNAL */
                if (mac68k_machine.serial_console != 0) {
                        cp->cn_pri = CN_REMOTE;  /* Higher than CN_INTERNAL */
                        mac68k_machine.serial_boot_echo =0;
                }

                unit = (mac68k_machine.serial_console == 1) ? 0 : 1;
                zs_consunit = unit;
                zs_conschan = (struct zschan *) -1; /* dummy flag for zs_init() */

                mac68k_zsdev = cp->cn_dev = makedev(maj, unit);
        }
        if (mac68k_machine.serial_boot_echo) {
                /*
                 * at this point, we know that we don't have a serial
                 * console, but are doing echo
                 */
                zs_conschan = (struct zschan *) -1; /* dummy flag for zs_init() */
                zs_consunit = 1;
                zs_hwflags[zs_consunit] = ZS_HWFLAG_CONSOLE;
        }

        if ((i = mac68k_machine.modem_d_speed) > 0) {
                if (zs_cn_check_speed(i))
                        zs_defspeed[0] = i;
        }
        if ((i = mac68k_machine.print_d_speed) > 0) {
                if (zs_cn_check_speed(i))
                        zs_defspeed[1] = i;
        }
        mac68k_set_io_offsets(IOBase);
        zs_init();
        /*
         * zsinit will set up the addresses of the scc. It will also, if
         * zs_conschan != 0, calculate the new address of the conschan for
         * unit zs_consunit. So if we are (or think we are) going to use the
         * chip for console I/O, we just set up the internal addresses for it.
         *
         * Now turn off interrupts for the chip. Note: using sccA to get at
         * the chip is the only vestige of the NetBSD 1.0 ser driver. :-)
         */
        unit = sccA[2];                 /* reset reg. access */
        unit = sccA[0];
        sccA[2] = 9; sccA[2] = 0;       /* write 0 to reg. 9, clearing MIE */
        sccA[2] = ZSWR0_CLR_INTR; unit = sccA[2]; /* reset any pending ints. */
        sccA[0] = ZSWR0_CLR_INTR; unit = sccA[0];

        if (mac68k_machine.serial_boot_echo)
                zscnsetup();
        return;
}

void
zscninit(struct consdev *cp)
{

        zs_hwflags[zs_consunit] = ZS_HWFLAG_CONSOLE;

        /*
         * zsinit will set up the addresses of the scc. It will also, if
         * zs_conschan != 0, calculate the new address of the conschan for
         * unit zs_consunit. So zs_init implicitly sets zs_conschan to the right
         * number. :-)
         */
        zscnsetup();
        printf("\nNetBSD/mac68k console\n");
}


/*
 * Polled input char.
 */
int
zs_getc(void *arg)
{
        volatile struct zschan *zc = arg;
        int s, c, rr0;

        s = splhigh();
        /* Wait for a character to arrive. */
        do {
                rr0 = zc->zc_csr;
                ZS_DELAY();
        } while ((rr0 & ZSRR0_RX_READY) == 0);

        c = zc->zc_data;
        ZS_DELAY();
        splx(s);

        /*
         * This is used by the kd driver to read scan codes,
         * so don't translate '\r' ==> '\n' here...
         */
        return (c);
}

/*
 * Polled output char.
 */
void
zs_putc(void *arg, int c)
{
        volatile struct zschan *zc = arg;
        int s, rr0;
        long wait = 0;

        s = splhigh();
        /* Wait for transmitter to become ready. */
        do {
                rr0 = zc->zc_csr;
                ZS_DELAY();
        } while (((rr0 & ZSRR0_TX_READY) == 0) && (wait++ < 1000000));

        if ((rr0 & ZSRR0_TX_READY) != 0) {
                zc->zc_data = c;
                ZS_DELAY();
        }
        splx(s);
}


/*
 * Polled console input putchar.
 */
int
zscngetc(dev_t dev)
{
        struct zschan *zc = zs_conschan;
        int c;

        c = zs_getc(zc);
        return (c);
}

/*
 * Polled console output putchar.
 */
void
zscnputc(dev_t dev, int c)
{
        struct zschan *zc = zs_conschan;

        zs_putc(zc, c);
}



/*
 * Handle user request to enter kernel debugger.
 */
void
zs_abort(struct zs_chanstate *cs)
{
        volatile struct zschan *zc = zs_conschan;
        int rr0;
        long wait = 0;

        if (zs_cons_canabort == 0)
                return;

        /* Wait for end of break to avoid PROM abort. */
        do {
                rr0 = zc->zc_csr;
                ZS_DELAY();
        } while ((rr0 & ZSRR0_BREAK) && (wait++ < ZSABORT_DELAY));

        if (wait > ZSABORT_DELAY) {
                zs_cons_canabort = 0;
        /* If we time out, turn off the abort ability! */
        }

#ifdef DDB
        Debugger();
#endif
}