/*      $NetBSD: ixp12x0_com.c,v 1.50 2022/07/21 10:09:20 andvar Exp $ */
/*
 * Copyright (c) 1998, 1999, 2001, 2002 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Ichiro FUKUHARA and Naoto Shimazaki.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by IWAMOTO Toshihiro.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Charles M. Hannum.
 *
 * 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) 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: ixp12x0_com.c,v 1.50 2022/07/21 10:09:20 andvar Exp $");

#include "opt_ddb.h"
#include "opt_kgdb.h"

#ifdef RND_COM
#include <sys/rndsource.h>
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/types.h>
#include <sys/conf.h>
#include <sys/file.h>
#include <sys/device.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/tty.h>
#include <sys/uio.h>
#include <sys/vnode.h>
#include <sys/kauth.h>
#include <sys/lwp.h>

#include <machine/intr.h>
#include <sys/bus.h>

#include <arm/ixp12x0/ixp12x0_comreg.h>
#include <arm/ixp12x0/ixp12x0_comvar.h>
#include <arm/ixp12x0/ixp12x0reg.h>
#include <arm/ixp12x0/ixp12x0var.h>

#include <arm/ixp12x0/ixpsipvar.h> 

#include <dev/cons.h>
#include "ixpcom.h"

static int      ixpcomparam(struct tty *, struct termios *);
static void     ixpcomstart(struct tty *);
static int      ixpcomhwiflow(struct tty *, int);

static u_int    cflag2cr(tcflag_t);
static void     ixpcom_iflush(struct ixpcom_softc *);
static void     ixpcom_set_cr(struct ixpcom_softc *);

int             ixpcomcngetc(dev_t);
void            ixpcomcnputc(dev_t, int);
void            ixpcomcnpollc(dev_t, int);

static void     ixpcomsoft(void* arg);
inline static void      ixpcom_txsoft(struct ixpcom_softc *, struct tty *);
inline static void      ixpcom_rxsoft(struct ixpcom_softc *, struct tty *);

void            ixpcomcnprobe(struct consdev *);
void            ixpcomcninit(struct consdev *);

uint32_t        ixpcom_cr = 0;          /* tell cr to *_intr.c */
uint32_t        ixpcom_imask = 0;       /* interrupt mask from *_intr.c */


static struct ixpcom_cons_softc {
        bus_space_tag_t         sc_iot;
        bus_space_handle_t      sc_ioh;
        bus_addr_t              sc_baseaddr;
        int                     sc_ospeed;
        tcflag_t                sc_cflag;
        int                     sc_attached;
} ixpcomcn_sc;

static struct cnm_state ixpcom_cnm_state;

struct ixpcom_softc* ixpcom_sc = NULL;

extern struct cfdriver ixpcom_cd;

dev_type_open(ixpcomopen);
dev_type_close(ixpcomclose);
dev_type_read(ixpcomread);
dev_type_write(ixpcomwrite);
dev_type_ioctl(ixpcomioctl);
dev_type_stop(ixpcomstop);
dev_type_tty(ixpcomtty);
dev_type_poll(ixpcompoll);

const struct cdevsw ixpcom_cdevsw = {
        .d_open = ixpcomopen,
        .d_close = ixpcomclose,
        .d_read = ixpcomread,
        .d_write = ixpcomwrite,
        .d_ioctl = ixpcomioctl,
        .d_stop = ixpcomstop,
        .d_tty = ixpcomtty,
        .d_poll = ixpcompoll,
        .d_mmap = nommap,
        .d_kqfilter = ttykqfilter,
        .d_discard = nodiscard,
        .d_flag = D_TTY
};

struct consdev ixpcomcons = {
        NULL, NULL, ixpcomcngetc, ixpcomcnputc, ixpcomcnpollc, NULL,
        NULL, NULL, NODEV, CN_NORMAL
};

#ifndef DEFAULT_COMSPEED
#define DEFAULT_COMSPEED 38400
#endif

#define COMUNIT(x)      TTUNIT(x)
#define COMDIALOUT(x)   TTDIALOUT(x)

#define COM_ISALIVE(sc) ((sc)->enabled != 0 && \
                         device_is_active((sc)->sc_dev))

#define COM_BARRIER(t, h, f) bus_space_barrier((t), (h), 0, COM_NPORTS, (f))

#define COM_LOCK(sc);
#define COM_UNLOCK(sc);

#define CFLAGS2CR_MASK  (CR_PE | CR_OES | CR_SBS | CR_DSS | CR_BRD)

void
ixpcom_attach_subr(struct ixpcom_softc *sc)
{
        struct tty *tp;

        ixpcom_sc = sc;

        /* force to use ixpcom0 for console */
        if (sc->sc_iot == ixpcomcn_sc.sc_iot
            && sc->sc_baseaddr == ixpcomcn_sc.sc_baseaddr) {
                ixpcomcn_sc.sc_attached = 1;
                sc->sc_speed = IXPCOMSPEED2BRD(ixpcomcn_sc.sc_ospeed);

                /* Make sure the console is always "hardwired". */
                /* XXX IXPCOM_SR should be checked  */
                delay(10000);   /* wait for output to finish */
                SET(sc->sc_hwflags, COM_HW_CONSOLE);
                SET(sc->sc_swflags, TIOCFLAG_SOFTCAR);
        }

        tp = tty_alloc();
        tp->t_oproc = ixpcomstart;
        tp->t_param = ixpcomparam;
        tp->t_hwiflow = ixpcomhwiflow;

        sc->sc_tty = tp;
        sc->sc_rbuf = kmem_alloc(IXPCOM_RING_SIZE << 1, KM_SLEEP);
        sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
        sc->sc_rbavail = IXPCOM_RING_SIZE;
        sc->sc_ebuf = sc->sc_rbuf + (IXPCOM_RING_SIZE << 1);
        sc->sc_tbc = 0;

        sc->sc_rie = sc->sc_xie = 0;
        ixpcom_cr = IXPCOMSPEED2BRD(DEFAULT_COMSPEED)
                | CR_UE | sc->sc_rie | sc->sc_xie | DSS_8BIT;

        tty_attach(tp);

        if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
                int maj;

                /* locate the major number */
                maj = cdevsw_lookup_major(&ixpcom_cdevsw);

                cn_tab->cn_dev = makedev(maj, device_unit(sc->sc_dev));

                aprint_normal("%s: console\n", device_xname(sc->sc_dev));
        }

        sc->sc_si = softint_establish(SOFTINT_SERIAL, ixpcomsoft, sc);

#ifdef RND_COM
        rnd_attach_source(&sc->rnd_source, device_xname(sc->sc_dev),
                          RND_TYPE_TTY, RND_FLAG_COLLECT_TIME|
                                        RND_FLAG_ESTIMATE_TIME);
#endif

        /* if there are no enable/disable functions, assume the device
           is always enabled */
        if (!sc->enable)
                sc->enabled = 1;

        /* XXX configure register */
        /* xxx_config(sc) */

        SET(sc->sc_hwflags, COM_HW_DEV_OK);
}

static int
ixpcomparam(struct tty *tp, struct termios *t)
{
        struct ixpcom_softc *sc
                = device_lookup_private(&ixpcom_cd, COMUNIT(tp->t_dev));
        uint32_t cr;
        int s;

        if (COM_ISALIVE(sc) == 0)
                return (EIO);

        cr = IXPCOMSPEED2BRD(t->c_ospeed);

        if (t->c_ispeed && t->c_ispeed != t->c_ospeed)
                return (EINVAL);

        /*
         * 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, COM_HW_CONSOLE)) {
                SET(t->c_cflag, CLOCAL);
                CLR(t->c_cflag, HUPCL);
        }

        /*
         * If there were no changes, don't do anything.  This avoids dropping
         * input and improves performance when all we did was frob things like
         * VMIN and VTIME.
         */
        if (tp->t_ospeed == t->c_ospeed &&
            tp->t_cflag == t->c_cflag)
                return (0);

        cr |= cflag2cr(t->c_cflag);

        s = splserial();
        COM_LOCK(sc);   
        
        ixpcom_cr = (ixpcom_cr & ~CFLAGS2CR_MASK) | cr;

        /*
         * ixpcom don't have any hardware flow control.
         * we skip it.
         */

        /* 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
                        ixpcom_set_cr(sc);
        }

        COM_UNLOCK(sc);
        splx(s);

        /*
         * Update the tty layer's idea of the carrier bit.
         * We tell tty the carrier is always on.
         */
        (void) (*tp->t_linesw->l_modem)(tp, 1);

#ifdef COM_DEBUG
        if (com_debug)
                comstatus(sc, "comparam ");
#endif

        if (!ISSET(t->c_cflag, CHWFLOW)) {
                if (sc->sc_tx_stopped) {
                        sc->sc_tx_stopped = 0;
                        ixpcomstart(tp);
                }
        }

        return (0);
}

static int
ixpcomhwiflow(struct tty *tp, int block)
{
        return (0);
}

static void
ixpcom_filltx(struct ixpcom_softc *sc)
{
        bus_space_tag_t iot = sc->sc_iot;
        bus_space_handle_t ioh = sc->sc_ioh;
        int n;

        n = 0;
        while (bus_space_read_4(iot, ioh, IXPCOM_SR) & SR_TXR) {
                if (n >= sc->sc_tbc)
                        break;
                bus_space_write_4(iot, ioh, IXPCOM_DR,
                                  0xff & *(sc->sc_tba + n));
                n++;
        }
        sc->sc_tbc -= n;
        sc->sc_tba += n;
}

static void
ixpcomstart(struct tty *tp)
{
        struct ixpcom_softc *sc
                = device_lookup_private(&ixpcom_cd, COMUNIT(tp->t_dev));
        int s;

        if (COM_ISALIVE(sc) == 0)
                return;

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

        if (!ttypull(tp))
                goto out;

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

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

                (void)splserial();
                COM_LOCK(sc);

                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_xie, CR_XIE)) {
                SET(sc->sc_xie, CR_XIE);
                ixpcom_set_cr(sc);
        }

        /* Output the first chunk of the contiguous buffer. */
        ixpcom_filltx(sc);

        COM_UNLOCK(sc);
out:
        splx(s);
        return;
}

static void
ixpcom_break(struct ixpcom_softc *sc, int onoff)
{
        if (onoff)
                SET(ixpcom_cr, CR_BRK);
        else
                CLR(ixpcom_cr, CR_BRK);
        if (!sc->sc_heldchange) {
                if (sc->sc_tx_busy) {
                        sc->sc_heldtbc = sc->sc_tbc;
                        sc->sc_tbc = 0;
                        sc->sc_heldchange = 1;
                } else
                        ixpcom_set_cr(sc);
        }
}

static void
ixpcom_shutdown(struct ixpcom_softc *sc)
{
        int s;

        s = splserial();
        COM_LOCK(sc);   

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

        /* Turn off interrupts. */
        sc->sc_rie = sc->sc_xie = 0;
        ixpcom_set_cr(sc);

        if (sc->disable) {
#ifdef DIAGNOSTIC
                if (!sc->enabled)
                        panic("ixpcom_shutdown: not enabled?");
#endif
                (*sc->disable)(sc);
                sc->enabled = 0;
        }
        COM_UNLOCK(sc);
        splx(s);
}

int
ixpcomopen(dev_t dev, int flag, int mode, struct lwp *l)
{
        struct ixpcom_softc *sc;
        struct tty *tp;
        int s, s2;
        int error;

        sc = device_lookup_private(&ixpcom_cd, COMUNIT(dev));
        if (sc == NULL || !ISSET(sc->sc_hwflags, COM_HW_DEV_OK) ||
                sc->sc_rbuf == NULL)
                return (ENXIO);

        if (!device_is_active(sc->sc_dev))
                return (ENXIO);

#ifdef KGDB
        /*
         * If this is the kgdb port, no other use is permitted.
         */
        if (ISSET(sc->sc_hwflags, COM_HW_KGDB))
                return (EBUSY);
#endif

        tp = sc->sc_tty;

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

        s = spltty();

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

                tp->t_dev = dev;

                s2 = splserial();
                COM_LOCK(sc);

                if (sc->enable) {
                        if ((*sc->enable)(sc)) {
                                COM_UNLOCK(sc);
                                splx(s2);
                                splx(s);
                                printf("%s: device enable failed\n",
                                       device_xname(sc->sc_dev));
                                return (EIO);
                        }
                        sc->enabled = 1;
#if 0
/* XXXXXXXXXXXXXXX */
                        com_config(sc);
#endif
                }

                /* Turn on interrupts. */
                SET(sc->sc_rie, CR_RIE);
                ixpcom_set_cr(sc);

#if 0
                /* Fetch the current modem control status, needed later. */
                sc->sc_msr = bus_space_read_1(sc->sc_iot, sc->sc_ioh, com_msr);

                /* Clear PPS capture state on first open. */
                sc->sc_ppsmask = 0;
                sc->ppsparam.mode = 0;
#endif

                COM_UNLOCK(sc);
                splx(s2);

                /*
                 * Initialize the termios status to the defaults.  Add in the
                 * sticky bits from TIOCSFLAGS.
                 */
                t.c_ispeed = 0;
                if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
                        t.c_ospeed = ixpcomcn_sc.sc_ospeed;
                        t.c_cflag = ixpcomcn_sc.sc_cflag;
                } 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);
                /* Make sure ixpcomparam() will do something. */
                tp->t_ospeed = 0;
                (void) ixpcomparam(tp, &t);
                tp->t_iflag = TTYDEF_IFLAG;
                tp->t_oflag = TTYDEF_OFLAG;
                tp->t_lflag = TTYDEF_LFLAG;
                ttychars(tp);
                ttsetwater(tp);

                s2 = splserial();
                COM_LOCK(sc);

                /* Clear the input ring, and unblock. */
                sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
                sc->sc_rbavail = IXPCOM_RING_SIZE;
                ixpcom_iflush(sc);
                CLR(sc->sc_rx_flags, RX_ANY_BLOCK);

#ifdef COM_DEBUG
                if (ixpcom_debug)
                        comstatus(sc, "ixpcomopen  ");
#endif

                COM_UNLOCK(sc);
                splx(s2);
        }
        
        splx(s);

        error = ttyopen(tp, COMDIALOUT(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.
                 */
                ixpcom_shutdown(sc);
        }

        return (error);
}

int
ixpcomclose(dev_t dev, int flag, int mode, struct lwp *l)
{
        struct ixpcom_softc *sc = device_lookup_private(&ixpcom_cd, COMUNIT(dev));
        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 (COM_ISALIVE(sc) == 0)
                return (0);

        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.
                 */
                ixpcom_shutdown(sc);
        }

        return (0);
}

int
ixpcomread(dev_t dev, struct uio *uio, int flag)
{
        struct ixpcom_softc *sc = device_lookup_private(&ixpcom_cd, COMUNIT(dev));
        struct tty *tp = sc->sc_tty;

        if (COM_ISALIVE(sc) == 0)
                return (EIO);
 
        return ((*tp->t_linesw->l_read)(tp, uio, flag));
}

int
ixpcomwrite(dev_t dev, struct uio *uio, int flag)
{
        struct ixpcom_softc *sc = device_lookup_private(&ixpcom_cd, COMUNIT(dev));
        struct tty *tp = sc->sc_tty;

        if (COM_ISALIVE(sc) == 0)
                return (EIO);
 
        return ((*tp->t_linesw->l_write)(tp, uio, flag));
}

int
ixpcompoll(dev_t dev, int events, struct lwp *l)
{
        struct ixpcom_softc *sc = device_lookup_private(&ixpcom_cd, COMUNIT(dev));
        struct tty *tp = sc->sc_tty;

        if (COM_ISALIVE(sc) == 0)
                return (EIO);
 
        return ((*tp->t_linesw->l_poll)(tp, events, l));
}

struct tty *
ixpcomtty(dev_t dev)
{
        struct ixpcom_softc *sc = device_lookup_private(&ixpcom_cd, COMUNIT(dev));
        struct tty *tp = sc->sc_tty;

        return (tp);
}

int
ixpcomioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
{
        struct ixpcom_softc *sc = device_lookup_private(&ixpcom_cd, COMUNIT(dev));
        struct tty *tp = sc->sc_tty;
        int error;
        int s;

        if (COM_ISALIVE(sc) == 0)
                return (EIO);

        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);

        error = 0;

        s = splserial();
        COM_LOCK(sc);   

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

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

        default:
                error = EPASSTHROUGH;
                break;
        }

        COM_UNLOCK(sc);
        splx(s);

        return (error);
}

/*
 * Stop output on a line.
 */
void
ixpcomstop(struct tty *tp, int flag)
{
        struct ixpcom_softc *sc
                = device_lookup_private(&ixpcom_cd, COMUNIT(tp->t_dev));
        int s;

        s = splserial();
        COM_LOCK(sc);
        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);
        }
        COM_UNLOCK(sc); 
        splx(s);
}

static u_int
cflag2cr(tcflag_t cflag)
{
        u_int cr;

        cr  = (cflag & PARENB) ? CR_PE : 0;
        cr |= (cflag & PARODD) ? CR_OES : 0;
        cr |= (cflag & CSTOPB) ? CR_SBS : 0;
        cr |= ((cflag & CSIZE) == CS8) ? DSS_8BIT : 0;
        
        return (cr);
}

static void
ixpcom_iflush(struct ixpcom_softc *sc)
{
        bus_space_tag_t iot = sc->sc_iot;
        bus_space_handle_t ioh = sc->sc_ioh;
#ifdef DIAGNOSTIC
        int reg;
#endif
        int timo;

#ifdef DIAGNOSTIC
        reg = 0xffff;
#endif
        timo = 50000;
        /* flush any pending I/O */
        while (ISSET(bus_space_read_4(iot, ioh, IXPCOM_SR), SR_RXR)
               && --timo)
#ifdef DIAGNOSTIC
                reg =
#else
                        (void)
#endif
                        bus_space_read_4(iot, ioh, IXPCOM_DR);
#ifdef DIAGNOSTIC
        if (!timo)
                printf("%s: com_iflush timeout %02x\n", device_xname(sc->sc_dev),
                       reg);
#endif
}

static void
ixpcom_set_cr(struct ixpcom_softc *sc)
{
        /* XXX */
        ixpcom_cr &= ~(CR_RIE | CR_XIE);
        ixpcom_cr |= sc->sc_rie | sc->sc_xie;
        bus_space_write_4(sc->sc_iot, sc->sc_ioh, IXPCOM_CR,
                          ixpcom_cr & ~ixpcom_imask);
}

int
ixpcomcnattach(bus_space_tag_t iot, bus_addr_t iobase, bus_space_handle_t ioh, int ospeed, tcflag_t cflag)
{
        int cr;

        cn_tab = &ixpcomcons;
        cn_init_magic(&ixpcom_cnm_state);
        /*
         * XXX
         *
         * ixpcom cannot detect a break.  It can only detect framing
         * errors.  And, a sequence of "framing error, framing error"
         * meens a break.  So I made this hack:
         *
         * 1. Set default magic is a sequence of "BREAK, BREAK".
         * 2. Tell cn_check_magic() a "framing error" as BREAK.
         *
         * see ixpcom_intr() too.
         *
         */
        /* default magic is a couple of BREAK. */
        cn_set_magic("\047\001\047\001");

        ixpcomcn_sc.sc_iot = iot;
        ixpcomcn_sc.sc_ioh = ioh;
        ixpcomcn_sc.sc_baseaddr = iobase;
        ixpcomcn_sc.sc_ospeed = ospeed;
        ixpcomcn_sc.sc_cflag = cflag;

        cr = cflag2cr(cflag);
        cr |= IXPCOMSPEED2BRD(ospeed);
        cr |= CR_UE;
        ixpcom_cr = cr;

        /* enable the UART */
        bus_space_write_4(iot, iobase, IXPCOM_CR, cr);

        return (0);
}

void
ixpcomcnprobe(struct consdev *cp)
{
        cp->cn_pri = CN_REMOTE;
}

void
ixpcomcnpollc(dev_t dev, int on)
{
}

void
ixpcomcnputc(dev_t dev, int c)
{
        int                     s;
        bus_space_tag_t         iot = ixpcomcn_sc.sc_iot;
        bus_space_handle_t      ioh = ixpcomcn_sc.sc_ioh;

        s = splserial();

        while(!(bus_space_read_4(iot, ioh, IXPCOM_SR) & SR_TXR))
                ;

        bus_space_write_4(iot, ioh, IXPCOM_DR, c);

#ifdef DEBUG
        if (c == '\r') {
                while(!(bus_space_read_4(iot, ioh, IXPCOM_SR) & SR_TXE))
                        ;
        }
#endif

        splx(s);
}

int
ixpcomcngetc(dev_t dev)
{
        int                     c;
        int                     s;
        bus_space_tag_t         iot = ixpcomcn_sc.sc_iot;
        bus_space_handle_t      ioh = ixpcomcn_sc.sc_ioh;

        s = splserial();

        while(!(bus_space_read_4(iot, ioh, IXPCOM_SR) & SR_RXR))
                ;

        c = bus_space_read_4(iot, ioh, IXPCOM_DR);
        c &= 0xff;
        splx(s);

        return (c);
}

inline static void
ixpcom_txsoft(struct ixpcom_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);
}

inline static void
ixpcom_rxsoft(struct ixpcom_softc *sc, struct tty *tp)
{
        int (*rint)(int, struct tty *) = tp->t_linesw->l_rint;
        u_char *get, *end;
        u_int cc, scc;
        u_char lsr;
        int code;
        int s;

        end = sc->sc_ebuf;
        get = sc->sc_rbget;
        scc = cc = IXPCOM_RING_SIZE - sc->sc_rbavail;
#if 0
        if (cc == IXPCOM_RING_SIZE) {
                sc->sc_floods++;
                if (sc->sc_errors++ == 0)
                        callout_reset(&sc->sc_diag_callout, 60 * hz,
                            comdiag, sc);
        }
#endif
        while (cc) {
                code = get[0];
                lsr = get[1];
                if (ISSET(lsr, DR_ROR | DR_FRE | DR_PRE)) {
#if 0
                        if (ISSET(lsr, DR_ROR)) {
                                sc->sc_overflows++;
                                if (sc->sc_errors++ == 0)
                                        callout_reset(&sc->sc_diag_callout,
                                            60 * hz, comdiag, sc);
                        }
#endif
                        if (ISSET(lsr, DR_FRE))
                                SET(code, TTY_FE);
                        if (ISSET(lsr, DR_PRE))
                                SET(code, TTY_PE);
                }
                if ((*rint)(code, tp) == -1) {
                        /*
                         * The line discipline's buffer is out of space.
                         */
                        if (!ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
                                /*
                                 * We're either not using flow control, or the
                                 * line discipline didn't tell us to block for
                                 * some reason.  Either way, we have no way to
                                 * know when there's more space available, so
                                 * just drop the rest of the data.
                                 */
                                get += cc << 1;
                                if (get >= end)
                                        get -= IXPCOM_RING_SIZE << 1;
                                cc = 0;
                        } else {
                                /*
                                 * Don't schedule any more receive processing
                                 * until the line discipline tells us there's
                                 * space available (through comhwiflow()).
                                 * Leave the rest of the data in the input
                                 * buffer.
                                 */
                                SET(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
                        }
                        break;
                }
                get += 2;
                if (get >= end)
                        get = sc->sc_rbuf;
                cc--;
        }

        if (cc != scc) {
                sc->sc_rbget = get;
                s = splserial();
                COM_LOCK(sc);
                
                cc = sc->sc_rbavail += scc - cc;
                /* Buffers should be ok again, release possible block. */
                if (cc >= 1) {
                        if (ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
                                CLR(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
                                SET(sc->sc_rie, CR_RIE);
                                ixpcom_set_cr(sc);
                        }
                        if (ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED)) {
                                CLR(sc->sc_rx_flags, RX_IBUF_BLOCKED);
#if 0
                                com_hwiflow(sc);
#endif
                        }
                }
                COM_UNLOCK(sc);
                splx(s);
        }
}

static void
ixpcomsoft(void* arg)
{
        struct ixpcom_softc *sc = arg;

        if (COM_ISALIVE(sc) == 0)
                return;

        if (sc->sc_rx_ready) {
                sc->sc_rx_ready = 0;
                ixpcom_rxsoft(sc, sc->sc_tty);
        }
        if (sc->sc_tx_done) {
                sc->sc_tx_done = 0;
                ixpcom_txsoft(sc, sc->sc_tty);
        }
}

int
ixpcomintr(void* arg)
{
        struct ixpcom_softc *sc = arg;
        bus_space_tag_t iot = sc->sc_iot;
        bus_space_handle_t ioh = sc->sc_ioh;
        u_char *put, *end;
        u_int cc;
        u_int cr;
        u_int sr;
        uint32_t c;

        if (COM_ISALIVE(sc) == 0)
                return (0);

        COM_LOCK(sc);
        cr = bus_space_read_4(iot, ioh, IXPCOM_CR) & CR_UE;

        if (!cr) {
                COM_UNLOCK(sc);
                return (0);
        }

        sr = bus_space_read_4(iot, ioh, IXPCOM_SR);
        if (!ISSET(sr, SR_TXR | SR_RXR))
                return (0);

        /*
         * XXX
         *
         * ixpcom cannot detect a break.  It can only detect framing
         * errors.  And, a sequence of "framing error, framing error"
         * meens a break.  So I made this hack:
         *
         * 1. Set default magic is a sequence of "BREAK, BREAK".
         * 2. Tell cn_check_magic() a "framing error" as BREAK.
         *
         * see ixpcomcnattach() too.
         *
         */
        if (ISSET(sr, SR_FRE)) {
                cn_check_magic(sc->sc_tty->t_dev,
                               CNC_BREAK, ixpcom_cnm_state);
        }

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

        if (ISSET(sr, SR_RXR)) {
                if (!ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
                        while (cc > 0) {
                                if (!ISSET(sr, SR_RXR))
                                        break;
                                c = bus_space_read_4(iot, ioh, IXPCOM_DR);
                                if (ISSET(c, DR_FRE)) {
                                        cn_check_magic(sc->sc_tty->t_dev,
                                                       CNC_BREAK,
                                                       ixpcom_cnm_state);
                                }
                                put[0] = c & 0xff;
                                put[1] = (c >> 8) & 0xff;
                                cn_check_magic(sc->sc_tty->t_dev,
                                               put[0], ixpcom_cnm_state);
                                put += 2;
                                if (put >= end)
                                        put = sc->sc_rbuf;
                                cc--;

                                sr = bus_space_read_4(iot, ioh, IXPCOM_SR);
                        }

                        /*
                         * Current string of incoming characters ended because
                         * no more data was available or we ran out of space.
                         * Schedule a receive event if any data was received.
                         * If we're out of space, turn off receive interrupts.
                         */
                        sc->sc_rbput = put;
                        sc->sc_rbavail = cc;
                        if (!ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED))
                                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.
                         */

                        /* but ixpcom cannot. X-( */

                        /*
                         * If we're out of space, disable receive interrupts
                         * until the queue has drained a bit.
                         */
                        if (!cc) {
                                SET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
                                CLR(sc->sc_rie, CR_RIE);
                                ixpcom_set_cr(sc);
                        }
                } else {
#ifdef DIAGNOSTIC
                        panic("ixpcomintr: we shouldn't reach here");
#endif
                        CLR(sc->sc_rie, CR_RIE);
                        ixpcom_set_cr(sc);
                }
        }

        /*
         * 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.
         */
        sr = bus_space_read_4(iot, ioh, IXPCOM_SR);
        if (ISSET(sr, SR_TXR)) {
                /*
                 * If we've delayed a parameter change, do it now, and restart
                 * output.
                 */
                if (sc->sc_heldchange) {
                        ixpcom_set_cr(sc);
                        sc->sc_heldchange = 0;
                        sc->sc_tbc = sc->sc_heldtbc;
                        sc->sc_heldtbc = 0;
                }

                /* Output the next chunk of the contiguous buffer, if any. */
                if (sc->sc_tbc > 0) {
                        ixpcom_filltx(sc);
                } else {
                        /* Disable transmit completion interrupts if necessary. */
                        if (ISSET(sc->sc_xie, CR_XIE)) {
                                CLR(sc->sc_xie, CR_XIE);
                                ixpcom_set_cr(sc);
                        }
                        if (sc->sc_tx_busy) {
                                sc->sc_tx_busy = 0;
                                sc->sc_tx_done = 1;
                        }
                }
        }
        COM_UNLOCK(sc);

        /* Wake up the poller. */
        softint_schedule(sc->sc_si);

#ifdef RND_COM
        rnd_add_uint32(&sc->rnd_source, iir | lsr);
#endif
        return (1);
}