/*      $NetBSD: ser.c,v 1.60 2025/08/18 20:59:55 andvar Exp $  */

/*-
 * Copyright (c) 1997 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Leo Weppelman.
 *
 * 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.
 */
/*-
 * Copyright (c) 1993, 1994, 1995, 1996, 1997
 *      Charles M. Hannum.  All rights reserved.
 *
 * Interrupt processing and hardware flow control partly based on code from
 * Onno van der Linden and Gordon Ross.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Charles M. Hannum.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * 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.
 */

/*
 * Copyright (c) 1991 The Regents of the University of California.
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *      @(#)com.c       7.5 (Berkeley) 5/16/91
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ser.c,v 1.60 2025/08/18 20:59:55 andvar Exp $");

#include "opt_ddb.h"
#include "opt_mbtype.h"
#include "opt_serconsole.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/ioctl.h>
#include <sys/select.h>
#include <sys/tty.h>
#include <sys/proc.h>
#include <sys/conf.h>
#include <sys/file.h>
#include <sys/uio.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/types.h>
#include <sys/device.h>
#include <sys/kauth.h>

#include <m68k/asm_single.h>

#include <machine/iomap.h>
#include <machine/mfp.h>
#include <machine/intr.h>
#include <atari/dev/serreg.h>

#include "ioconf.h"

#if !defined(_MILANHW_)
#include <atari/dev/ym2149reg.h>
#else
        /* MILAN has no ym2149 */
#define ym2149_dtr(set) {                                       \
        if (set)                                                \
                single_inst_bset_b(MFP->mf_gpip, 0x08);         \
        else                                                    \
                single_inst_bclr_b(MFP->mf_gpip, 0x08);         \
}

#define ym2149_rts(set) {                                       \
        if (set)                                                \
                single_inst_bset_b(MFP->mf_gpip, 0x01);         \
        else                                                    \
                single_inst_bclr_b(MFP->mf_gpip, 0x01);         \
}
#endif /* _MILANHW_ */

/* #define SER_DEBUG */

#define SERUNIT(x)      TTUNIT(x)
#define SERDIALOUT(x)   TTDIALOUT(x)

/* XXX */
#define CONSBAUD        9600
#define CONSCFLAG       TTYDEF_CFLAG
/* end XXX */

/* Buffer size for character buffer */
#define RXBUFSIZE 2048          /* More than enough..                   */
#define RXBUFMASK (RXBUFSIZE-1) /* Only iff previous is a power of 2    */
#define RXHIWAT   (RXBUFSIZE >> 2)

struct ser_softc {
        device_t         sc_dev;
        struct tty      *sc_tty;

        struct callout sc_diag_ch;

        int              sc_overflows;
        int              sc_floods;
        int              sc_errors;

        uint8_t          sc_hwflags;
        uint8_t          sc_swflags;

        int              sc_ospeed;             /* delay + timer-d data */
        uint8_t          sc_imra;
        uint8_t          sc_imrb;
        uint8_t          sc_ucr;                /* Uart control         */
        uint8_t          sc_msr;                /* Modem status         */
        uint8_t          sc_tsr;                /* Transceiver status   */
        uint8_t          sc_rsr;                /* Receiver status      */
        uint8_t          sc_mcr;                /* (Pseudo) Modem ctrl. */

        uint8_t          sc_msr_delta;
        uint8_t          sc_msr_mask;
        uint8_t          sc_mcr_active;
        uint8_t          sc_mcr_dtr, sc_mcr_rts, sc_msr_cts, sc_msr_dcd;

        int              sc_r_hiwat;
        volatile u_int   sc_rbget;
        volatile u_int   sc_rbput;
        volatile u_int   sc_rbavail;
        uint8_t          sc_rbuf[RXBUFSIZE];
        uint8_t          sc_lbuf[RXBUFSIZE];

        volatile uint8_t sc_rx_blocked;
        volatile uint8_t sc_rx_ready;
        volatile uint8_t sc_tx_busy;
        volatile uint8_t sc_tx_done;
        volatile uint8_t sc_tx_stopped;
        volatile uint8_t sc_st_check;

        uint8_t         *sc_tba;
        int              sc_tbc;
        int              sc_heldtbc;

        volatile uint8_t sc_heldchange;

        void            *sc_sicookie;
};

/*
 * For sc_hwflags:
 */
#define SER_HW_CONSOLE  0x01

static void     ser_break(struct ser_softc *, int);
static void     ser_hwiflow(struct ser_softc *, int);
static void     ser_iflush(struct ser_softc *);
static void     ser_loadchannelregs(struct ser_softc *);
static void     ser_modem(struct ser_softc *, int);
static void     serdiag(void *);
static int      serhwiflow(struct tty *, int);
static void     serinit(int);
static void     serinitcons(int);
static int      sermintr(void *);
static int      sertrintr(void *);
static int      serparam(struct tty *, struct termios *);
static void     serstart(struct tty *);

struct consdev;
void    sercnprobe(struct consdev *);
void    sercninit(struct consdev *);
int     sercngetc(dev_t);
void    sercnputc(dev_t, int);
void    sercnpollc(dev_t, int);

static void sermsrint(struct ser_softc *, struct tty*);
static void serrxint(struct ser_softc *, struct tty*);
static void ser_shutdown(struct ser_softc *);
static int serspeed(long);
static void sersoft(void *);
static void sertxint(struct ser_softc *, struct tty*);

/*
 * Autoconfig stuff
 */
static int  sermatch(device_t, cfdata_t, void *);
static void serattach(device_t, device_t, void *);

CFATTACH_DECL_NEW(ser, sizeof(struct ser_softc),
    sermatch, serattach, NULL, NULL);

static dev_type_open(seropen);
static dev_type_close(serclose);
static dev_type_read(serread);
static dev_type_write(serwrite);
static dev_type_ioctl(serioctl);
static dev_type_stop(serstop);
static dev_type_tty(sertty);
static dev_type_poll(serpoll);

const struct cdevsw ser_cdevsw = {
        .d_open = seropen,
        .d_close = serclose,
        .d_read = serread,
        .d_write = serwrite,
        .d_ioctl = serioctl,
        .d_stop = serstop,
        .d_tty = sertty,
        .d_poll = serpoll,
        .d_mmap = nommap,
        .d_kqfilter = ttykqfilter,
        .d_discard = nodiscard,
        .d_flag = D_TTY
};

#ifndef SERCONSOLE
#define SERCONSOLE      0
#endif
int serconsole = SERCONSOLE;    /* patchable */

/*ARGSUSED*/
static  int
sermatch(device_t parent, cfdata_t cf, void *aux)
{
        static int ser_matched = 0;

        /* Match at most one ser unit */
        if (strcmp((char *)aux, "ser") || ser_matched)
                return 0;

        ser_matched = 1;
        return 1;
}

/*ARGSUSED*/
static void
serattach(device_t parent, device_t self, void *aux)
{
        struct ser_softc *sc = device_private(self);

        sc->sc_dev = self;

        if (intr_establish(1, USER_VEC, 0, (hw_ifun_t)sermintr, sc) == NULL)
                aprint_error(": Can't establish interrupt (1)\n");
        if (intr_establish(2, USER_VEC, 0, (hw_ifun_t)sermintr, sc) == NULL)
                aprint_error(": Can't establish interrupt (2)\n");
        if (intr_establish(14, USER_VEC, 0, (hw_ifun_t)sermintr, sc) == NULL)
                aprint_error(": Can't establish interrupt (14)\n");
        if (intr_establish(9, USER_VEC, 0, (hw_ifun_t)sertrintr, sc) == NULL)
                aprint_error(": Can't establish interrupt (9)\n");
        if (intr_establish(10, USER_VEC, 0, (hw_ifun_t)sertrintr, sc) == NULL)
                aprint_error(": Can't establish interrupt (10)\n");
        if (intr_establish(11, USER_VEC, 0, (hw_ifun_t)sertrintr, sc) == NULL)
                aprint_error(": Can't establish interrupt (11)\n");
        if (intr_establish(12, USER_VEC, 0, (hw_ifun_t)sertrintr, sc) == NULL)
                aprint_error(": Can't establish interrupt (12)\n");

        sc->sc_sicookie = softint_establish(SOFTINT_SERIAL, sersoft, sc);

        ym2149_rts(1);
        ym2149_dtr(1);

        /*
         * Enable but mask interrupts...
         * XXX: Look at edge-sensitivity for DCD/CTS interrupts.
         */
        MFP->mf_ierb |= IB_SCTS|IB_SDCD;
        MFP->mf_iera |= IA_RRDY|IA_RERR|IA_TRDY|IA_TERR;
        MFP->mf_imrb &= ~(IB_SCTS|IB_SDCD);
        MFP->mf_imra &= ~(IA_RRDY|IA_RERR|IA_TRDY|IA_TERR);

        callout_init(&sc->sc_diag_ch, 0);

        if (serconsole) {
                /*
                 * Activate serial console when DCD present...
                 */
                if ((MFP->mf_gpip & MCR_DCD) == 0)
                        SET(sc->sc_hwflags, SER_HW_CONSOLE);
        }

        aprint_normal(": modem1 on 68901 MFP1 USART\n");
        if (ISSET(sc->sc_hwflags, SER_HW_CONSOLE)) {
                serinit(CONSBAUD);
                aprint_normal_dev(self, "console\n");
        }
}

#ifdef SER_DEBUG
void serstatus(struct ser_softc *, const char *);
void
serstatus(struct ser_softc *sc, const char *str)
{
        struct tty *tp = sc->sc_tty;

        printf("%s: %s %sclocal  %sdcd %sts_carr_on %sdtr %stx_stopped\n",
            device_xname(sc->sc_dev), str,
            ISSET(tp->t_cflag, CLOCAL) ? "+" : "-",
            ISSET(sc->sc_msr, MCR_DCD) ? "+" : "-",
            ISSET(tp->t_state, TS_CARR_ON) ? "+" : "-",
            ISSET(sc->sc_mcr, MCR_DTR) ? "+" : "-",
            sc->sc_tx_stopped ? "+" : "-");

        printf("%s: %s %scrtscts %scts %sts_ttstop  %srts %srx_blocked\n",
            device_xname(sc->sc_dev), str,
            ISSET(tp->t_cflag, CRTSCTS) ? "+" : "-",
            ISSET(sc->sc_msr, MCR_CTS) ? "+" : "-",
            ISSET(tp->t_state, TS_TTSTOP) ? "+" : "-",
            ISSET(sc->sc_mcr, MCR_RTS) ? "+" : "-",
            sc->sc_rx_blocked ? "+" : "-");
}
#endif /* SER_DEBUG */

static int
seropen(dev_t dev, int flag, int mode, struct lwp *l)
{
        int unit = SERUNIT(dev);
        struct ser_softc *sc;
        struct tty *tp;
        int s, s2;
        int error = 0;

        sc = device_lookup_private(&ser_cd, unit);
        if (sc == NULL)
                return ENXIO;

        if (!sc->sc_tty) {
                tp = sc->sc_tty = tty_alloc();
                tty_attach(tp);
        } else
                tp = sc->sc_tty;

        if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_OPEN, tp))
                return EBUSY;

        s = spltty();

        /*
         * Do the following if this is a first open.
         */
        if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
                struct termios t;

                /* Turn on interrupts. */
                sc->sc_imra = IA_RRDY|IA_RERR|IA_TRDY|IA_TERR;
                sc->sc_imrb = IB_SCTS|IB_SDCD;
                single_inst_bset_b(MFP->mf_imra, sc->sc_imra);
                single_inst_bset_b(MFP->mf_imrb, sc->sc_imrb);

                /* Fetch the current modem control status, needed later. */
                sc->sc_msr = ~MFP->mf_gpip & (IO_SDCD|IO_SCTS|IO_SRI);

                /* Add some entry points needed by the tty layer. */
                tp->t_oproc = serstart;
                tp->t_param = serparam;
                tp->t_hwiflow = serhwiflow;
                tp->t_dev = dev;

                /*
                 * Initialize the termios status to the defaults.  Add in the
                 * sticky bits from TIOCSFLAGS.
                 */
                t.c_ispeed = 0;
                if (ISSET(sc->sc_hwflags, SER_HW_CONSOLE)) {
                        t.c_ospeed = CONSBAUD;
                        t.c_cflag  = CONSCFLAG;
                } else {
                        t.c_ospeed = TTYDEF_SPEED;
                        t.c_cflag = TTYDEF_CFLAG;
                }
                if (ISSET(sc->sc_swflags, TIOCFLAG_CLOCAL))
                        SET(t.c_cflag, CLOCAL);
                if (ISSET(sc->sc_swflags, TIOCFLAG_CRTSCTS))
                        SET(t.c_cflag, CRTSCTS);
                if (ISSET(sc->sc_swflags, TIOCFLAG_MDMBUF))
                        SET(t.c_cflag, MDMBUF);
                tp->t_iflag = TTYDEF_IFLAG;
                tp->t_oflag = TTYDEF_OFLAG;
                tp->t_lflag = TTYDEF_LFLAG;
                ttychars(tp);
                (void)serparam(tp, &t);
                ttsetwater(tp);

                s2 = splhigh();

                /*
                 * Turn on DTR.  We must always do this, even if carrier is not
                 * present, because otherwise we'd have to use TIOCSDTR
                 * immediately after setting CLOCAL.  We will drop DTR only on
                 * the next high-low transition of DCD, or by explicit request.
                 */
                ser_modem(sc, 1);

                /* Clear the input ring, and unblock. */
                sc->sc_rbput = sc->sc_rbget = 0;
                sc->sc_rbavail = RXBUFSIZE;
                ser_iflush(sc);
                sc->sc_rx_blocked = 0;
                ser_hwiflow(sc, 0);

#ifdef SER_DEBUG
                serstatus(sc, "seropen  ");
#endif

                splx(s2);
        }

        splx(s);

        error = ttyopen(tp, SERDIALOUT(dev), ISSET(flag, O_NONBLOCK));
        if (error)
                goto bad;

        error = (*tp->t_linesw->l_open)(dev, tp);
        if (error)
                goto bad;

        return 0;

bad:
        if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
                /*
                 * We failed to open the device, and nobody else had it opened.
                 * Clean up the state as appropriate.
                 */
                ser_shutdown(sc);
        }

        return error;
}

static int
serclose(dev_t dev, int flag, int mode, struct lwp *l)
{
        int unit = SERUNIT(dev);
        struct ser_softc *sc = device_lookup_private(&ser_cd, unit);
        struct tty *tp = sc->sc_tty;

        /* XXX This is for cons.c. */
        if (!ISSET(tp->t_state, TS_ISOPEN))
                return 0;

        (*tp->t_linesw->l_close)(tp, flag);
        ttyclose(tp);

        if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
                /*
                 * Although we got a last close, the device may still be in
                 * use; e.g. if this was the dialout node, and there are still
                 * processes waiting for carrier on the non-dialout node.
                 */
                ser_shutdown(sc);
        }

        return 0;
}

static int
serread(dev_t dev, struct uio *uio, int flag)
{
        struct ser_softc *sc = device_lookup_private(&ser_cd, SERUNIT(dev));
        struct tty *tp = sc->sc_tty;

        return (*tp->t_linesw->l_read)(tp, uio, flag);
}

static int
serwrite(dev_t dev, struct uio *uio, int flag)
{
        struct ser_softc *sc = device_lookup_private(&ser_cd, SERUNIT(dev));
        struct tty *tp = sc->sc_tty;

        return (*tp->t_linesw->l_write)(tp, uio, flag);
}

static int
serpoll(dev_t dev, int events, struct lwp *l)
{
        struct ser_softc *sc = device_lookup_private(&ser_cd, SERUNIT(dev));
        struct tty *tp = sc->sc_tty;

        return (*tp->t_linesw->l_poll)(tp, events, l);
}

static struct tty *
sertty(dev_t dev)
{
        struct ser_softc *sc = device_lookup_private(&ser_cd, SERUNIT(dev));
        struct tty *tp = sc->sc_tty;

        return tp;
}

static int
serioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
{
        int unit = SERUNIT(dev);
        struct ser_softc *sc = device_lookup_private(&ser_cd, unit);
        struct tty *tp = sc->sc_tty;
        int error;

        error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, l);
        if (error != EPASSTHROUGH)
                return error;

        error = ttioctl(tp, cmd, data, flag, l);
        if (error != EPASSTHROUGH)
                return error;

        switch (cmd) {
        case TIOCSBRK:
                ser_break(sc, 1);
                break;

        case TIOCCBRK:
                ser_break(sc, 0);
                break;

        case TIOCSDTR:
                ser_modem(sc, 1);
                break;

        case TIOCCDTR:
                ser_modem(sc, 0);
                break;

        case TIOCGFLAGS:
                *(int *)data = sc->sc_swflags;
                break;

        case TIOCSFLAGS:
                error = kauth_authorize_device_tty(l->l_cred,
                    KAUTH_DEVICE_TTY_PRIVSET, tp);
                if (error)
                        return error;
                sc->sc_swflags = *(int *)data;
                break;

        case TIOCMSET:
        case TIOCMBIS:
        case TIOCMBIC:
        case TIOCMGET:
        default:
                return EPASSTHROUGH;
        }

#ifdef SER_DEBUG
        serstatus(sc, "serioctl ");
#endif

        return 0;
}

void
ser_break(struct ser_softc *sc, int onoff)
{
        int s;

        s = splhigh();
        if (onoff)
                SET(sc->sc_tsr, TSR_SBREAK);
        else
                CLR(sc->sc_tsr, TSR_SBREAK);

        if (!sc->sc_heldchange) {
                if (sc->sc_tx_busy) {
                        sc->sc_heldtbc = sc->sc_tbc;
                        sc->sc_tbc = 0;
                        sc->sc_heldchange = 1;
                } else
                        ser_loadchannelregs(sc);
        }
        splx(s);
}

void
ser_modem(struct ser_softc *sc, int onoff)
{
        int s;

        s = splhigh();
        if (onoff)
                SET(sc->sc_mcr, sc->sc_mcr_dtr);
        else
                CLR(sc->sc_mcr, sc->sc_mcr_dtr);

        if (!sc->sc_heldchange) {
                if (sc->sc_tx_busy) {
                        sc->sc_heldtbc = sc->sc_tbc;
                        sc->sc_tbc = 0;
                        sc->sc_heldchange = 1;
                } else
                        ser_loadchannelregs(sc);
        }
        splx(s);
}

int
serparam(struct tty *tp, struct termios *t)
{
        struct ser_softc *sc =
            device_lookup_private(&ser_cd, SERUNIT(tp->t_dev));
        int ospeed = serspeed(t->c_ospeed);
        uint8_t ucr;
        int s;


        /* check requested parameters */
        if (ospeed < 0)
                return EINVAL;
        if (t->c_ispeed && t->c_ispeed != t->c_ospeed)
                return EINVAL;

        sc->sc_rsr = RSR_ENAB;
        sc->sc_tsr = TSR_ENAB;

        ucr = UCR_CLKDIV;

        switch (ISSET(t->c_cflag, CSIZE)) {
        case CS5:
                SET(ucr, UCR_5BITS);
                break;
        case CS6:
                SET(ucr, UCR_6BITS);
                break;
        case CS7:
                SET(ucr, UCR_7BITS);
                break;
        case CS8:
                SET(ucr, UCR_8BITS);
                break;
        }
        if (ISSET(t->c_cflag, PARENB)) {
                SET(ucr, UCR_PENAB);
                if (!ISSET(t->c_cflag, PARODD))
                        SET(ucr, UCR_PEVEN);
        }
        if (ISSET(t->c_cflag, CSTOPB))
                SET(ucr, UCR_STOPB2);
        else
                SET(ucr, UCR_STOPB1);

        s = splhigh();

        sc->sc_ucr = ucr;

        /*
         * For the console, always force CLOCAL and !HUPCL, so that the port
         * is always active.
         */
        if (ISSET(sc->sc_swflags, TIOCFLAG_SOFTCAR) ||
            ISSET(sc->sc_hwflags, SER_HW_CONSOLE)) {
                SET(t->c_cflag, CLOCAL);
                CLR(t->c_cflag, HUPCL);
        }

        /*
         * If we're not in a mode that assumes a connection is present, then
         * ignore carrier changes.
         */
        if (ISSET(t->c_cflag, CLOCAL | MDMBUF))
                sc->sc_msr_dcd = 0;
        else
                sc->sc_msr_dcd = MCR_DCD;
        /*
         * Set the flow control pins depending on the current flow control
         * mode.
         */
        if (ISSET(t->c_cflag, CRTSCTS)) {
                sc->sc_mcr_dtr = MCR_DTR;
                sc->sc_mcr_rts = MCR_RTS;
                sc->sc_msr_cts = MCR_CTS;
                sc->sc_r_hiwat = RXHIWAT;
        } else if (ISSET(t->c_cflag, MDMBUF)) {
                /*
                 * For DTR/DCD flow control, make sure we don't toggle DTR for
                 * carrier detection.
                 */
                sc->sc_mcr_dtr = 0;
                sc->sc_mcr_rts = MCR_DTR;
                sc->sc_msr_cts = MCR_DCD;
                sc->sc_r_hiwat = RXHIWAT;
        } else {
                /*
                 * If no flow control, then always set RTS.  This will make
                 * the other side happy if it mistakenly thinks we're doing
                 * RTS/CTS flow control.
                 */
                sc->sc_mcr_dtr = MCR_DTR | MCR_RTS;
                sc->sc_mcr_rts = 0;
                sc->sc_msr_cts = 0;
                sc->sc_r_hiwat = 0;
                if (ISSET(sc->sc_mcr, MCR_DTR))
                        SET(sc->sc_mcr, MCR_RTS);
                else
                        CLR(sc->sc_mcr, MCR_RTS);
        }
        sc->sc_msr_mask = sc->sc_msr_cts | sc->sc_msr_dcd;

#if 0
        if (ospeed == 0)
                CLR(sc->sc_mcr, sc->sc_mcr_dtr);
        else
                SET(sc->sc_mcr, sc->sc_mcr_dtr);
#endif

        sc->sc_ospeed = ospeed;

        /* and copy to tty */
        tp->t_ispeed = 0;
        tp->t_ospeed = t->c_ospeed;
        tp->t_cflag = t->c_cflag;

        if (!sc->sc_heldchange) {
                if (sc->sc_tx_busy) {
                        sc->sc_heldtbc = sc->sc_tbc;
                        sc->sc_tbc = 0;
                        sc->sc_heldchange = 1;
                } else
                        ser_loadchannelregs(sc);
        }

        splx(s);

        /*
         * Update the tty layer's idea of the carrier bit, in case we changed
         * CLOCAL or MDMBUF.  We don't hang up here; we only do that if we
         * lose carrier while carrier detection is on.
         */
        (void)(*tp->t_linesw->l_modem)(tp, ISSET(sc->sc_msr, MCR_DCD));

#ifdef SER_DEBUG
        serstatus(sc, "serparam ");
#endif

        /* XXXXX FIX ME */
        /* Block or unblock as needed. */
        if (!ISSET(t->c_cflag, CHWFLOW)) {
                if (sc->sc_rx_blocked) {
                        sc->sc_rx_blocked = 0;
                        ser_hwiflow(sc, 0);
                }
                if (sc->sc_tx_stopped) {
                        sc->sc_tx_stopped = 0;
                        serstart(tp);
                }
        } else {
#if 0
                sermsrint(sc, tp);
#endif
        }

        return 0;
}

void
ser_iflush(struct ser_softc *sc)
{
        uint8_t tmp;

        /* flush any pending I/O */
        while (ISSET(MFP->mf_rsr, RSR_CIP|RSR_BFULL))
                tmp = MFP->mf_udr;
        __USE(tmp);
}

void
ser_loadchannelregs(struct ser_softc *sc)
{

        /* XXXXX necessary? */
        ser_iflush(sc);

        /*
         * No interrupts please...
         */
        if ((MFP->mf_imra & (IA_RRDY|IA_RERR|IA_TRDY|IA_TERR)) != sc->sc_imra) {
                printf("loadchannelregs: mf_imra: %x sc_imra: %x\n",
                    (u_int)MFP->mf_imra, (u_int)sc->sc_imra);
        }
        if ((MFP->mf_imrb & (IB_SCTS|IB_SDCD)) != sc->sc_imrb) {
                printf("loadchannelregs: mf_imrb: %x sc_imrb: %x\n",
                     (u_int)MFP->mf_imrb, (u_int)sc->sc_imrb);
        }
        single_inst_bclr_b(MFP->mf_imra, IA_RRDY|IA_RERR|IA_TRDY|IA_TERR);
        single_inst_bclr_b(MFP->mf_imrb, IB_SCTS|IB_SDCD);

        MFP->mf_ucr = sc->sc_ucr;
        MFP->mf_rsr = sc->sc_rsr;
        MFP->mf_tsr = sc->sc_tsr;

        single_inst_bclr_b(MFP->mf_tcdcr, 0x07);
        MFP->mf_tddr  = sc->sc_ospeed;
        single_inst_bset_b(MFP->mf_tcdcr, (sc->sc_ospeed >> 8) & 0x0f);

        sc->sc_mcr_active = sc->sc_mcr;

        if (machineid & ATARI_HADES) {
                /* PCB fault, wires exchanged..... */
                ym2149_rts(!(sc->sc_mcr_active & MCR_DTR));
                ym2149_dtr(!(sc->sc_mcr_active & MCR_RTS));
        } else {
                ym2149_rts(!(sc->sc_mcr_active & MCR_RTS));
                ym2149_dtr(!(sc->sc_mcr_active & MCR_DTR));
        }

        single_inst_bset_b(MFP->mf_imra, sc->sc_imra);
        single_inst_bset_b(MFP->mf_imrb, sc->sc_imrb);
}

int
serhwiflow(struct tty *tp, int block)
{
        struct ser_softc *sc =
            device_lookup_private(&ser_cd, SERUNIT(tp->t_dev));
        int s;

        if (sc->sc_mcr_rts == 0)
                return 0;

        s = splhigh();
        if (block) {
                /*
                 * The tty layer is asking us to block input.
                 * If we already did it, just return TRUE.
                 */
                if (sc->sc_rx_blocked)
                        goto out;
                sc->sc_rx_blocked = 1;
        } else {
                /*
                 * The tty layer is asking us to resume input.
                 * The input ring is always empty by now.
                 */
                sc->sc_rx_blocked = 0;
        }
        ser_hwiflow(sc, block);
out:
        splx(s);
        return 1;
}

/*
 * (un)block input via hw flowcontrol
 */
void
ser_hwiflow(struct ser_softc *sc, int block)
{

        if (sc->sc_mcr_rts == 0)
                return;

        if (block) {
                CLR(sc->sc_mcr, sc->sc_mcr_rts);
                CLR(sc->sc_mcr_active, sc->sc_mcr_rts);
        } else {
                SET(sc->sc_mcr, sc->sc_mcr_rts);
                SET(sc->sc_mcr_active, sc->sc_mcr_rts);
        }
        if (machineid & ATARI_HADES) {
                /* PCB fault, wires exchanged..... */
                ym2149_dtr(sc->sc_mcr_active & MCR_RTS);
        }
        else {
                ym2149_rts(sc->sc_mcr_active & MCR_RTS);
        }
}

void
serstart(struct tty *tp)
{
        struct ser_softc *sc =
            device_lookup_private(&ser_cd, SERUNIT(tp->t_dev));
        int s;

        s = spltty();
        if (ISSET(tp->t_state, TS_BUSY))
                goto out;
        if (ISSET(tp->t_state, TS_TIMEOUT | TS_TTSTOP))
                goto stopped;

        if (sc->sc_tx_stopped)
                goto stopped;
        if (!ttypull(tp))
                goto stopped;

        /* Grab the first contiguous region of buffer space. */
        {
                uint8_t *tba;
                int tbc;

                tba = tp->t_outq.c_cf;
                tbc = ndqb(&tp->t_outq, 0);

                (void)splhigh();

                sc->sc_tba = tba;
                sc->sc_tbc = tbc;
        }

        SET(tp->t_state, TS_BUSY);
        sc->sc_tx_busy = 1;

        /* Enable transmit completion interrupts if necessary. */
        if (!ISSET(sc->sc_imra, IA_TRDY)) {
                SET(sc->sc_imra, IA_TRDY|IA_TERR);
                single_inst_bset_b(MFP->mf_imra, IA_TRDY|IA_TERR);
        }

        /* Output the first char */
        MFP->mf_udr = *sc->sc_tba;
        sc->sc_tbc--;
        sc->sc_tba++;

        splx(s);
        return;

stopped:
        /* Disable transmit completion interrupts if necessary. */
        if (ISSET(sc->sc_imra, IA_TRDY)) {
                CLR(sc->sc_imra, IA_TRDY|IA_TERR);
                single_inst_bclr_b(MFP->mf_imra, IA_TRDY|IA_TERR);
        }
out:
        splx(s);
        return;
}

/*
 * Stop output on a line.
 */
static void
serstop(struct tty *tp, int flag)
{
        struct ser_softc *sc =
            device_lookup_private(&ser_cd, SERUNIT(tp->t_dev));
        int s;

        s = splhigh();
        if (ISSET(tp->t_state, TS_BUSY)) {
                /* Stop transmitting at the next chunk. */
                sc->sc_tbc = 0;
                sc->sc_heldtbc = 0;
                if (!ISSET(tp->t_state, TS_TTSTOP))
                        SET(tp->t_state, TS_FLUSH);
        }
        splx(s);
}

void
serdiag(void *arg)
{
        struct ser_softc *sc = arg;
        int overflows, floods;
        int s;

        s = splhigh();
        overflows = sc->sc_overflows;
        sc->sc_overflows = 0;
        floods = sc->sc_floods;
        sc->sc_floods = 0;
        sc->sc_errors = 0;
        splx(s);

        log(LOG_WARNING,
            "%s: %d silo overflow%s, %d ibuf flood%s\n",
            device_xname(sc->sc_dev),
            overflows, overflows == 1 ? "" : "s",
            floods, floods == 1 ? "" : "s");
}

static void
ser_shutdown(struct ser_softc *sc)
{
        int s;
        struct tty *tp = sc->sc_tty;


        s = splhigh();

        /* If we were asserting flow control, then deassert it. */
        sc->sc_rx_blocked = 1;
        ser_hwiflow(sc, 1);

        /* Clear any break condition set with TIOCSBRK. */
        ser_break(sc, 0);

        /*
         * Hang up if necessary.  Wait a bit, so the other side has time to
         * notice even if we immediately open the port again.
         */
        if (ISSET(tp->t_cflag, HUPCL)) {
                ser_modem(sc, 0);
                (void)tsleep(sc, TTIPRI, ttclos, hz);
        }

        /* Turn off interrupts. */
        CLR(sc->sc_imra, IA_RRDY|IA_RERR|IA_TRDY|IA_TERR);
        CLR(sc->sc_imrb, IB_SCTS|IB_SDCD);
        single_inst_bclr_b(MFP->mf_imrb, IB_SCTS|IB_SDCD);
        single_inst_bclr_b(MFP->mf_imra, IA_RRDY|IA_RERR|IA_TRDY|IA_TERR);
        splx(s);
}

static void
serrxint(struct ser_softc *sc, struct tty *tp)
{
        u_int get, cc, scc;
        int code;
        uint8_t rsr;
        int s;
        static const int lsrmap[8] = {
                0,      TTY_PE,
                TTY_FE, TTY_PE|TTY_FE,
                TTY_FE, TTY_PE|TTY_FE,
                TTY_FE, TTY_PE|TTY_FE
        };

        get = sc->sc_rbget;
        scc = cc = RXBUFSIZE - sc->sc_rbavail;

        if (cc == RXBUFSIZE) {
                sc->sc_floods++;
                if (sc->sc_errors++ == 0)
                        callout_reset(&sc->sc_diag_ch, 60 * hz, serdiag, sc);
        }

        while (cc--) {
                rsr = sc->sc_lbuf[get];
                if (ISSET(rsr, RSR_BREAK)) {
#ifdef DDB
                        if (ISSET(sc->sc_hwflags, SER_HW_CONSOLE))
                                Debugger();
#endif
                } else if (ISSET(rsr, RSR_OERR)) {
                        sc->sc_overflows++;
                        if (sc->sc_errors++ == 0)
                                callout_reset(&sc->sc_diag_ch, 60 * hz,
                                    serdiag, sc);
                }
                code = sc->sc_rbuf[get] |
                    lsrmap[(rsr & (RSR_BREAK|RSR_FERR|RSR_PERR)) >> 3];
                (*tp->t_linesw->l_rint)(code, tp);
                get = (get + 1) & RXBUFMASK;
        }

        sc->sc_rbget = get;
        s = splhigh();
        sc->sc_rbavail += scc;
        /*
         * Buffers should be ok again, release possible block, but only if the
         * tty layer isn't blocking too.
         */
        if (sc->sc_rx_blocked && !ISSET(tp->t_state, TS_TBLOCK)) {
                sc->sc_rx_blocked = 0;
                ser_hwiflow(sc, 0);
        }
        splx(s);
}

static void
sertxint(struct ser_softc *sc, struct tty *tp)
{

        CLR(tp->t_state, TS_BUSY);
        if (ISSET(tp->t_state, TS_FLUSH))
                CLR(tp->t_state, TS_FLUSH);
        else
                ndflush(&tp->t_outq, (int)(sc->sc_tba - tp->t_outq.c_cf));
        (*tp->t_linesw->l_start)(tp);
}

static void
sermsrint(struct ser_softc *sc, struct tty *tp)
{
        uint8_t msr, delta;
        int s;

        s = splhigh();
        msr = sc->sc_msr;
        delta = sc->sc_msr_delta;
        sc->sc_msr_delta = 0;
        splx(s);

        if (ISSET(delta, sc->sc_msr_dcd)) {
                /*
                 * Inform the tty layer that carrier detect changed.
                 */
                (void)(*tp->t_linesw->l_modem)(tp, ISSET(msr, MCR_DCD));
        }

        if (ISSET(delta, sc->sc_msr_cts)) {
                /* Block or unblock output according to flow control. */
                if (ISSET(msr, sc->sc_msr_cts)) {
                        sc->sc_tx_stopped = 0;
                        (*tp->t_linesw->l_start)(tp);
                } else {
                        sc->sc_tx_stopped = 1;
                        serstop(tp, 0);
                }
        }

#ifdef SER_DEBUG
        serstatus(sc, "sermsrint");
#endif
}

void
sersoft(void *arg)
{
        struct ser_softc *sc = arg;
        struct tty *tp;

        tp = sc->sc_tty;
        if (tp == NULL)
                return;

        if (!ISSET(tp->t_state, TS_ISOPEN) && (tp->t_wopen == 0))
                return;

        if (sc->sc_rx_ready) {
                sc->sc_rx_ready = 0;
                serrxint(sc, tp);
        }

        if (sc->sc_st_check) {
                sc->sc_st_check = 0;
                sermsrint(sc, tp);
        }

        if (sc->sc_tx_done) {
                sc->sc_tx_done = 0;
                sertxint(sc, tp);
        }
}

int
sermintr(void *arg)
{
        struct ser_softc *sc = arg;
        uint8_t msr, delta;

        msr = ~MFP->mf_gpip;
        delta = msr ^ sc->sc_msr;
        sc->sc_msr  = sc->sc_msr & ~(MCR_CTS|MCR_DCD|MCR_RI);
        sc->sc_msr |= msr & (MCR_CTS|MCR_DCD|MCR_RI);

        if (ISSET(delta, sc->sc_msr_mask)) {
                sc->sc_msr_delta |= delta;

                /*
                 * Stop output immediately if we lose the output
                 * flow control signal or carrier detect.
                 */
                if (ISSET(~msr, sc->sc_msr_mask)) {
                        sc->sc_tbc = 0;
                        sc->sc_heldtbc = 0;
#ifdef SER_DEBUG
                        serstatus(sc, "sermintr  ");
#endif
                }

                sc->sc_st_check = 1;
        }
        softint_schedule(sc->sc_sicookie);
        return 1;
}

int
sertrintr(void *arg)
{
        struct ser_softc *sc = arg;
        u_int put, cc;
        uint8_t rsr, tsr;

        put = sc->sc_rbput;
        cc = sc->sc_rbavail;

        rsr = MFP->mf_rsr;
        if (ISSET(rsr, RSR_BFULL|RSR_BREAK)) {
                for (; ISSET(rsr, RSR_BFULL|RSR_BREAK) && cc > 0; cc--) {
                        sc->sc_rbuf[put] = MFP->mf_udr;
                        sc->sc_lbuf[put] = rsr;
                        put = (put + 1) & RXBUFMASK;
                        if ((rsr & RSR_BREAK) && (MFP->mf_rsr & RSR_BREAK))
                                rsr = 0;
                        else
                                rsr = MFP->mf_rsr;
                }
                /*
                 * Current string of incoming characters ended because
                 * no more data was available. Schedule a receive event
                 * if any data was received. Drop any characters that
                 * we couldn't handle.
                 */
                sc->sc_rbput    = put;
                sc->sc_rbavail  = cc;
                sc->sc_rx_ready = 1;
                /*
                 * See if we are in danger of overflowing a buffer. If
                 * so, use hardware flow control to ease the pressure.
                 */
                if (sc->sc_rx_blocked == 0 &&
                    cc < sc->sc_r_hiwat) {
                        sc->sc_rx_blocked = 1;
                        ser_hwiflow(sc, 1);
                }
                /*
                 * If we're out of space, throw away any further input.
                 */
                if (!cc) {
                        while (ISSET(rsr, RSR_BFULL|RSR_BREAK)) {
                                rsr = MFP->mf_udr;
                                rsr = MFP->mf_rsr;
                        }
                }
        }

        /*
         * Done handling any receive interrupts. See if data can be
         * transmitted as well. Schedule tx done event if no data left
         * and tty was marked busy.
         */
        tsr = MFP->mf_tsr;
        if (ISSET(tsr, TSR_BE)) {
                /*
                 * If we've delayed a parameter change, do it now, and restart
                 * output.
                 */
                if (sc->sc_heldchange) {
                        ser_loadchannelregs(sc);
                        sc->sc_heldchange = 0;
                        sc->sc_tbc = sc->sc_heldtbc;
                        sc->sc_heldtbc = 0;
                }
                /* Output the next character, if any. */
                if (sc->sc_tbc > 0) {
                        MFP->mf_udr = *sc->sc_tba;
                        sc->sc_tbc--;
                        sc->sc_tba++;
                } else if (sc->sc_tx_busy) {
                        sc->sc_tx_busy = 0;
                        sc->sc_tx_done = 1;
                }
        }
        softint_schedule(sc->sc_sicookie);
        return 1;
}

static int
serspeed(long speed)
{
#define divrnd(n, q)    (((n)*2/(q)+1)/2)       /* divide and round off */

        int div, x, err;

        if (speed <= 0)
                return -1;

        for (div = 4; div <= 64; div *= 4) {
                x = divrnd((SER_FREQ / div), speed);

                /*
                 * The value must fit in the timer-d dataregister. If
                 * not, try another delay-mode.
                 */
                if ((x / 2) > 255)
                        continue;

                /*
                 * Baudrate to high for the interface or cannot be made
                 * within tolerance.
                 */
                if (x <= 0)
                        return -1;

                err = divrnd((SER_FREQ / div) * 1000, speed * x) - 1000;
                if (err < 0)
                        err = -err;
                if (err > SER_TOLERANCE)
                        continue;

                /*
                 * Translate 'div' to delay-code
                 */
                if (div == 4)
                        div = 1;
                else if (div == 16)
                        div = 3;
                else if (div == 64)
                        div = 5;

                return (x / 2) | (div << 8);
        }
        return -1;

#undef  divrnd
}

/*
 * Following are all routines needed for SER to act as console
 */
#include <dev/cons.h>

void
sercnprobe(struct consdev *cp)
{

        /*
         * Activate serial console when DCD present...
         */
        if (MFP->mf_gpip & MCR_DCD) {
                cp->cn_pri = CN_DEAD;
                return;
        }

        /* initialize required fields */
        /* XXX: LWP What unit? */
        cp->cn_dev = makedev(cdevsw_lookup_major(&ser_cdevsw), 0);
        if (serconsole)
                cp->cn_pri = CN_REMOTE; /* Force a serial port console */
        else
                cp->cn_pri = CN_NORMAL;
}

void
sercninit(struct consdev *cp)
{

        serinitcons(CONSBAUD);
}

/*
 * Initialize UART to known state.
 */
void
serinit(int baud)
{
        int ospeed = serspeed(baud);

        MFP->mf_ucr = UCR_CLKDIV|UCR_8BITS|UCR_STOPB1;
        MFP->mf_rsr = RSR_ENAB;
        MFP->mf_tsr = TSR_ENAB;

        single_inst_bclr_b(MFP->mf_tcdcr, 0x07);
        MFP->mf_tddr  = ospeed;
        single_inst_bset_b(MFP->mf_tcdcr, (ospeed >> 8) & 0x0f);
}

/*
 * Set UART for console use. Do normal init, then enable interrupts.
 */
void
serinitcons(int baud)
{

        serinit(baud);

        /* Set rts/dtr */
        ym2149_rts(0);
        ym2149_dtr(0);

        single_inst_bset_b(MFP->mf_imra, (IA_RRDY|IA_RERR|IA_TRDY|IA_TERR));
}

int
sercngetc(dev_t dev)
{
        uint8_t stat, c;
        int s;

        s = splhigh();
        while (!ISSET(stat = MFP->mf_rsr, RSR_BFULL)) {
                if (!ISSET(stat, RSR_ENAB)) /* XXX */
                        MFP->mf_rsr |= RSR_ENAB;
                if (stat & (RSR_FERR|RSR_PERR|RSR_OERR))
                        c = MFP->mf_udr;
        }
        c = MFP->mf_udr;
        splx(s);
        return c;
}

#if 1
u_int s_imra;
u_int s_stat1, s_stat2, s_stat3;
#endif
void
sercnputc(dev_t dev, int c)
{
        int timo;
        uint8_t stat, imra;

        /* Mask serial interrupts */
        imra  = MFP->mf_imra & (IA_RRDY|IA_RERR|IA_TRDY|IA_TERR);
        single_inst_bclr_b(MFP->mf_imra, imra);
#if 1
        s_imra = imra;
#endif

        /* wait for any pending transmission to finish */
        timo = 50000;
#if 1
        s_stat1 = MFP->mf_tsr;
#endif
        while (!ISSET(stat = MFP->mf_tsr, TSR_BE) && --timo)
                ;
        MFP->mf_udr = c;
        /* wait for this transmission to complete */
        timo = 1500000;
#if 1
        s_stat2 = MFP->mf_tsr;
#endif
        while (!ISSET(stat = MFP->mf_tsr, TSR_BE) && --timo)
                ;

#if 1
        s_stat3 = MFP->mf_tsr;
#endif
        /* Clear pending serial interrupts and re-enable */
        MFP->mf_ipra = (uint8_t)~imra;
        single_inst_bset_b(MFP->mf_imra, imra);
}

void
sercnpollc(dev_t dev, int on)
{

}