/*      $NetBSD: sa11x0_com.c,v 1.59 2022/10/26 23:38:07 riastradh Exp $        */

/*-
 * Copyright (c) 1998, 1999, 2001 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * 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: sa11x0_com.c,v 1.59 2022/10/26 23:38:07 riastradh Exp $");

#include "opt_com.h"
#include "opt_console.h"
#include "opt_ddb.h"
#include "opt_ddbparam.h"
#include "opt_kgdb.h"
#include "opt_multiprocessor.h"
#include "opt_lockdebug.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 <ddb/db_active.h>

#include <dev/cons.h>

#include <sys/bus.h>
#include <arm/sa11x0/sa11x0_reg.h>
#include <arm/sa11x0/sa11x0_var.h>
#include <arm/sa11x0/sa11x0_comreg.h>
#include <arm/sa11x0/sa11x0_comvar.h>
#include <arm/sa11x0/sa11x0_gpioreg.h>

#ifdef hpcarm
#include <hpc/include/platid.h>
#include <hpc/include/platid_mask.h>
#endif

#include "sacom.h"

dev_type_open(sacomopen);
dev_type_close(sacomclose);
dev_type_read(sacomread);
dev_type_write(sacomwrite);
dev_type_ioctl(sacomioctl);
dev_type_stop(sacomstop);
dev_type_tty(sacomtty);
dev_type_poll(sacompoll);

const struct cdevsw sacom_cdevsw = {
        .d_open = sacomopen,
        .d_close = sacomclose,
        .d_read = sacomread,
        .d_write = sacomwrite,
        .d_ioctl = sacomioctl,
        .d_stop = sacomstop,
        .d_tty = sacomtty,
        .d_poll = sacompoll,
        .d_mmap = nommap,
        .d_kqfilter = ttykqfilter,
        .d_discard = nodiscard,
        .d_flag = D_TTY
};

static  int     sacom_match(device_t, cfdata_t, void *);
static  void    sacom_attach(device_t, device_t, void *);
static  void    sacom_filltx(struct sacom_softc *);
static  void    sacom_attach_subr(struct sacom_softc *);
#if defined(DDB) || defined(KGDB)
static  void    sacom_enable_debugport(struct sacom_softc *);
#endif
int             sacom_detach(device_t, int);
void            sacom_config(struct sacom_softc *);
int             sacom_activate(device_t, enum devact);
void            sacom_shutdown(struct sacom_softc *);
static  u_int   cflag2cr0(tcflag_t);
int             sacomparam(struct tty *, struct termios *);
void            sacomstart(struct tty *);
int             sacomhwiflow(struct tty *, int);

void            sacom_loadchannelregs(struct sacom_softc *);
void            sacom_hwiflow(struct sacom_softc *);
void            sacom_break(struct sacom_softc *, int);
void            sacom_modem(struct sacom_softc *, int);
void            tiocm_to_sacom(struct sacom_softc *, u_long, int);
int             sacom_to_tiocm(struct sacom_softc *);
void            sacom_iflush(struct sacom_softc *);

int             sacominit(bus_space_tag_t, bus_addr_t, int, tcflag_t,
                          bus_space_handle_t *);
int             sacom_is_console(bus_space_tag_t, bus_addr_t,
                                 bus_space_handle_t *);

void            sacomsoft(void *);

static inline void sacom_rxsoft(struct sacom_softc *, struct tty *);
static inline void sacom_txsoft(struct sacom_softc *, struct tty *);
static inline void sacom_stsoft(struct sacom_softc *, struct tty *);
static inline void sacom_schedrx(struct sacom_softc *);

#ifdef hpcarm
/* HPCARM specific functions */
static void     sacom_j720_init(device_t, device_t);
#endif

#define COMDIALOUT_MASK TTDIALOUT_MASK

#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)

int             sacomintr(void *);
int             sacomcngetc(dev_t);
void            sacomcnputc(dev_t, int);
void            sacomcnpollc(dev_t, int);

void            sacomcnprobe(struct consdev *);
void            sacomcninit(struct consdev *);

extern struct bus_space sa11x0_bs_tag;

static bus_space_tag_t sacomconstag;
static bus_space_handle_t sacomconsioh;
static bus_addr_t sacomconsaddr = SACOM3_BASE; /* XXX */

static int sacomconsattached;
static int sacomconsrate;
static tcflag_t sacomconscflag;

CFATTACH_DECL_NEW(sacom, sizeof(struct sacom_softc),
    sacom_match, sacom_attach, NULL, NULL);
extern struct cfdriver sacom_cd;

#ifdef hpcarm
struct platid_data sacom_platid_table[] = {
        { &platid_mask_MACH_HP_JORNADA_7XX, sacom_j720_init },
        { NULL, NULL }
};
#endif

struct consdev sacomcons = {
        NULL, NULL, sacomcngetc, sacomcnputc, sacomcnpollc, NULL,
        NULL, NULL, NODEV, CN_NORMAL
};

#ifndef CONMODE
#define CONMODE ((TTYDEF_CFLAG & ~(CSIZE | CSTOPB | PARENB)) | CS8) /* 8N1 */
#endif
#ifndef CONSPEED
#define CONSPEED 9600
#endif
#ifndef CONADDR
#define CONADDR SACOM3_BASE
#endif

static int
sacom_match(device_t parent, cfdata_t match, void *aux)
{

        return 1;
}

void
sacom_attach(device_t parent, device_t self, void *aux)
{
        struct sacom_softc *sc = device_private(self);
        struct sa11x0_attach_args *sa = aux;

#ifdef hpcarm
        struct platid_data *p;
        void (*mdinit)(device_t, device_t);
#endif

        aprint_normal("\n");

        sc->sc_dev = self;
        sc->sc_iot = sa->sa_iot;
        sc->sc_baseaddr = sa->sa_addr;

        if (bus_space_map(sa->sa_iot, sa->sa_addr, sa->sa_size, 0,
            &sc->sc_ioh)) {
                aprint_normal_dev(self, "unable to map registers\n");
                return;
        }

        switch (sc->sc_baseaddr) {
        case SACOM1_BASE:
                aprint_normal_dev(self, "SA-11x0 UART1\n");
                break;
        case SACOM2_BASE:
                aprint_normal_dev(self, "SA-11x0 UART2 (IRDA)\n");
                break;
        case SACOM3_BASE:
                aprint_normal_dev(self, "SA-11x0 UART3\n");
                break;
        default:
                aprint_normal_dev(self, "unknown SA-11x0 UART\n");
                break;
        }

        sacom_attach_subr(sc);

#ifdef hpcarm
        /* Do hpcarm specific initialization, if any */
        if ((p = platid_search_data(&platid, sacom_platid_table)) != NULL) {
                mdinit = p->data;
                (*mdinit)(parent, self);
        }
#endif

        sa11x0_intr_establish(0, sa->sa_intr, 1, IPL_SERIAL, sacomintr, sc);
}

void
sacom_attach_subr(struct sacom_softc *sc)
{
        bus_addr_t iobase = sc->sc_baseaddr;
        bus_space_tag_t iot = sc->sc_iot;
        struct tty *tp;

        /* XXX Do we need to disable interrupts here? */

        if (iot == sacomconstag && iobase == sacomconsaddr) {
                sacomconsattached = 1;
                sc->sc_speed = SACOMSPEED(sacomconsrate);

                /* Make sure the console is always "hardwired". */
                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 = sacomstart;
        tp->t_param = sacomparam;
        tp->t_hwiflow = sacomhwiflow;

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

        tty_attach(tp);

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

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

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

                delay(10000); /* XXX */
                aprint_normal_dev(sc->sc_dev, "console\n");
                delay(10000); /* XXX */
        }


        sc->sc_si = softint_establish(SOFTINT_SERIAL, sacomsoft, 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;

        sacom_config(sc);

        SET(sc->sc_hwflags, COM_HW_DEV_OK);
}

/* This is necessary when dynamically changing SAIP configuration. */
int
sacom_detach(device_t dev, int flags)
{
        struct sacom_softc *sc = device_private(dev);
        int maj, mn;

        if (sc->sc_hwflags & (COM_HW_CONSOLE|COM_HW_KGDB))
                return EBUSY;

        if (sc->disable != NULL && sc->enabled != 0) {
                (*sc->disable)(sc);
                sc->enabled = 0;
        }

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

        /* Nuke the vnodes for any open instances. */
        mn = device_unit(dev);
        vdevgone(maj, mn, mn, VCHR);

        mn |= COMDIALOUT_MASK;
        vdevgone(maj, mn, mn, VCHR);

        /* Free the receive buffer. */
        kmem_free(sc->sc_rbuf, SACOM_RING_SIZE << 1);

        /* Detach and free the tty. */
        tty_detach(sc->sc_tty);
        tty_free(sc->sc_tty);

        /* Unhook the soft interrupt handler. */
        softint_disestablish(sc->sc_si);

#ifdef RND_COM
        /* Unhook the entropy source. */
        rnd_detach_source(&sc->rnd_source);
#endif

        return 0;
}

void
sacom_config(struct sacom_softc *sc)
{
        bus_space_tag_t iot = sc->sc_iot;
        bus_space_handle_t ioh = sc->sc_ioh;

        /* Disable engine before configuring the device. */
        sc->sc_cr3 = 0;
        bus_space_write_4(iot, ioh, SACOM_CR3, sc->sc_cr3);

#ifdef DDB
        if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE))
                sacom_enable_debugport(sc);
#endif
}

#ifdef DDB
static void
sacom_enable_debugport(struct sacom_softc *sc)
{
        bus_space_tag_t iot = sc->sc_iot;
        bus_space_handle_t ioh = sc->sc_ioh;
        int s;

        s = splserial();
        COM_LOCK(sc);
        sc->sc_cr3 = CR3_RXE | CR3_TXE;
        bus_space_write_4(iot, ioh, SACOM_CR3, sc->sc_cr3);
        COM_UNLOCK(sc);
        splx(s);
}
#endif

int
sacom_activate(device_t dev, enum devact act)
{
        struct sacom_softc *sc = device_private(dev);

        switch (act) {
        case DVACT_DEACTIVATE:
                sc->enabled = 0;
                return 0;
        default:
                return EOPNOTSUPP;
        }
}

void
sacom_shutdown(struct sacom_softc *sc)
{
        struct tty *tp = sc->sc_tty;
        int s;

        s = splserial();
        COM_LOCK(sc);   

        /* Clear any break condition set with TIOCSBRK. */
        sacom_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.
         * Avoid tsleeping above splhigh().
         */
        if (ISSET(tp->t_cflag, HUPCL)) {
                sacom_modem(sc, 0);
                COM_UNLOCK(sc);
                splx(s);
                /* XXX tsleep will only timeout */
                (void) tsleep(sc, TTIPRI, ttclos, hz);
                s = splserial();
                COM_LOCK(sc);   
        }

        /* Turn off interrupts. */
        sc->sc_cr3 = 0;
        bus_space_write_4(sc->sc_iot, sc->sc_ioh, SACOM_CR3, sc->sc_cr3);

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

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

        sc = device_lookup_private(&sacom_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;

        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);
                                aprint_normal_dev(sc->sc_dev, "device enable failed\n");
                                return EIO;
                        }
                        sc->enabled = 1;
                        sacom_config(sc);
                }

                /* Turn on interrupts. */
                sc->sc_cr3 = CR3_RXE | CR3_TXE | CR3_RIE | CR3_TIE;
                bus_space_write_4(sc->sc_iot, sc->sc_ioh, SACOM_CR3,
                                  sc->sc_cr3);


                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 = sacomconsrate;
                        t.c_cflag = sacomconscflag;
                } 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 sacomparam() will do something. */
                tp->t_ospeed = 0;
                (void) sacomparam(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);

                /*
                 * 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, which applications do not
                 * expect.  We always assert DTR while the device is open
                 * unless explicitly requested to deassert it.
                 */
                sacom_modem(sc, 1);

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

#ifdef COM_DEBUG
                if (sacom_debug)
                        comstatus(sc, "sacomopen  ");
#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.
                 */
                sacom_shutdown(sc);
        }

        return error;
}
 
int
sacomclose(dev_t dev, int flag, int mode, struct lwp *l)
{
        struct sacom_softc *sc =
                device_lookup_private(&sacom_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.
                 */
                sacom_shutdown(sc);
        }

        return 0;
}
 
int
sacomread(dev_t dev, struct uio *uio, int flag)
{
        struct sacom_softc *sc =
                device_lookup_private(&sacom_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
sacomwrite(dev_t dev, struct uio *uio, int flag)
{
        struct sacom_softc *sc =
                device_lookup_private(&sacom_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
sacompoll(dev_t dev, int events, struct lwp *l)
{
        struct sacom_softc *sc =
                device_lookup_private(&sacom_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 *
sacomtty(dev_t dev)
{
        struct sacom_softc *sc =
                device_lookup_private(&sacom_cd, COMUNIT(dev));
        struct tty *tp = sc->sc_tty;

        return tp;
}

int
sacomioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
{
        struct sacom_softc *sc =
                device_lookup_private(&sacom_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:
                sacom_break(sc, 1);
                break;

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

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

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

        case TIOCMSET:
        case TIOCMBIS:
        case TIOCMBIC:
                tiocm_to_sacom(sc, cmd, *(int *)data);
                break;

        case TIOCMGET:
                *(int *)data = sacom_to_tiocm(sc);
                break;

        default:
                error = EPASSTHROUGH;
                break;
        }

        COM_UNLOCK(sc);
        splx(s);

#ifdef COM_DEBUG
        if (sacom_debug)
                comstatus(sc, "comioctl ");
#endif

        return error;
}

static inline void
sacom_schedrx(struct sacom_softc *sc)
{

        sc->sc_rx_ready = 1;

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

void
sacom_break(struct sacom_softc *sc, int onoff)
{

        if (onoff)
                SET(sc->sc_cr3, CR3_BRK);
        else
                CLR(sc->sc_cr3, CR3_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
                        sacom_loadchannelregs(sc);
        }
}

void
sacom_modem(struct sacom_softc *sc, int onoff)
{
        if (!sc->sc_heldchange) {
                if (sc->sc_tx_busy) {
                        sc->sc_heldtbc = sc->sc_tbc;
                        sc->sc_tbc = 0;
                        sc->sc_heldchange = 1;
                } else
                        sacom_loadchannelregs(sc);
        }
}

void
tiocm_to_sacom(struct sacom_softc *sc, u_long how, int ttybits)
{
}

int
sacom_to_tiocm(struct sacom_softc *sc)
{
        int ttybits = 0;

        if (sc->sc_cr3 != 0)
                SET(ttybits, TIOCM_LE);

        return ttybits;
}

static u_int
cflag2cr0(tcflag_t cflag)
{
        u_int cr0;

        cr0  = (cflag & PARENB) ? CR0_PE : 0;
        cr0 |= (cflag & PARODD) ? 0 : CR0_OES;
        cr0 |= (cflag & CSTOPB) ? CR0_SBS : 0;
        cr0 |= ((cflag & CSIZE) == CS8) ? CR0_DSS : 0;

        return cr0;
}

int
sacomparam(struct tty *tp, struct termios *t)
{
        struct sacom_softc *sc =
                device_lookup_private(&sacom_cd, COMUNIT(tp->t_dev));
        int ospeed = SACOMSPEED(t->c_ospeed);
        u_int cr0;
        int s;

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

        /* Check requested parameters. */
        if (ospeed < 0)
                return EINVAL;
        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;

        cr0 = cflag2cr0(t->c_cflag);

        s = splserial();
        COM_LOCK(sc);   

        sc->sc_cr0 = cr0;

        sc->sc_speed = 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
                        sacom_loadchannelregs(sc);
        }

        if (!ISSET(t->c_cflag, CHWFLOW)) {
                /* Disable the high water mark. */
                if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
                        CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
                        sacom_schedrx(sc);
                }
                if (ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED)) {
                        CLR(sc->sc_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED);
                        sacom_hwiflow(sc);
                }
        }

        COM_UNLOCK(sc);
        splx(s);

        (void) (*tp->t_linesw->l_modem)(tp, 1);

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

        return 0;
}

void
sacom_iflush(struct sacom_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 = 50;
        /* flush any pending I/O */
        if (sc->sc_cr3 & CR3_RXE) {
        while (ISSET(bus_space_read_4(iot, ioh, SACOM_SR1), SR1_RNE)
            && --timo)
#ifdef DIAGNOSTIC
                reg =
#else
                    (void)
#endif
                    bus_space_read_4(iot, ioh, SACOM_DR);
        }
#if 0
        /* XXX is it good idea to wait TX finish? */
        if (sc->sc_cr3 & CR3_TXE) {
        timo = 500;
        while (ISSET(bus_space_read_4(iot, ioh, SACOM_SR1), SR1_TBY)
            && --timo)
                delay(100);
        }
#endif
#ifdef DIAGNOSTIC
        if (!timo)
                aprint_debug_dev(sc->sc_dev, "sacom_iflush timeout %02x\n", reg);
#endif
}

void
sacom_loadchannelregs(struct sacom_softc *sc)
{
        bus_space_tag_t iot = sc->sc_iot;
        bus_space_handle_t ioh = sc->sc_ioh;

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

        /* Need to stop engines first. */
        bus_space_write_4(iot, ioh, SACOM_CR3, 0);

        bus_space_write_4(iot, ioh, SACOM_CR1, sc->sc_speed >> 8);
        bus_space_write_4(iot, ioh, SACOM_CR2, sc->sc_speed & 0xff);

        bus_space_write_4(iot, ioh, SACOM_CR0, sc->sc_cr0);
        bus_space_write_4(iot, ioh, SACOM_CR3, sc->sc_cr3);
}

int
sacomhwiflow(struct tty *tp, int block)
{
#if 0
        struct sacom_softc *sc =
                device_lookup_private(&sacom_cd, COMUNIT(tp->t_dev));
        int s;

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

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

        s = splserial();
        COM_LOCK(sc);
        
        if (block) {
                if (!ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
                        SET(sc->sc_rx_flags, RX_TTY_BLOCKED);
                        sacom_hwiflow(sc);
                }
        } else {
                if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
                        CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
                        sacom_schedrx(sc);
                }
                if (ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
                        CLR(sc->sc_rx_flags, RX_TTY_BLOCKED);
                        sacom_hwiflow(sc);
                }
        }

        COM_UNLOCK(sc);
        splx(s);
#endif
        return 1;
}
        
/*
 * (un)block input via hw flowcontrol
 */
void
sacom_hwiflow(struct sacom_softc *sc)
{
#if 0
        bus_space_tag_t iot = sc->sc_iot;
        bus_space_handle_t ioh = sc->sc_ioh;

        /* XXX implement */
#endif
}


void
sacomstart(struct tty *tp)
{
        struct sacom_softc *sc =
                device_lookup_private(&sacom_cd, COMUNIT(tp->t_dev));
        bus_space_tag_t iot = sc->sc_iot;
        bus_space_handle_t ioh = sc->sc_ioh;
        int s;

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

        s = spltty();
        if (ISSET(tp->t_state, TS_BUSY | TS_TIMEOUT | TS_TTSTOP))
                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_cr3, CR3_TIE)) {
                SET(sc->sc_cr3, CR3_TIE);
                bus_space_write_4(iot, ioh, SACOM_CR3, sc->sc_cr3);
        }

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

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

void
sacom_filltx(struct sacom_softc *sc)
{
        bus_space_tag_t iot = sc->sc_iot;
        bus_space_handle_t ioh = sc->sc_ioh;
        int c, n;

        n = 0;
        while (bus_space_read_4(iot, ioh, SACOM_SR1) & SR1_TNF) {
                if (n == SACOM_TXFIFOLEN || n == sc->sc_tbc)
                        break;
                c = *(sc->sc_tba + n);
                c &= 0xff;
                bus_space_write_4(iot, ioh, SACOM_DR, c);
                n++;
        }
        sc->sc_tbc -= n;
        sc->sc_tba += n;
}

/*
 * Stop output on a line.
 */
void
sacomstop(struct tty *tp, int flag)
{
        struct sacom_softc *sc =
                device_lookup_private(&sacom_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 inline void
sacom_rxsoft(struct sacom_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 sr1;
        int code;
        int s;

        end = sc->sc_ebuf;
        get = sc->sc_rbget;
        scc = cc = SACOM_RING_SIZE - sc->sc_rbavail;

        while (cc) {
                code = get[0];
                sr1 = get[1];
                if (ISSET(sr1, SR1_FRE))
                        SET(code, TTY_FE);
                if (ISSET(sr1, SR1_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 -= SACOM_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_cr3, CR3_RIE);
                                bus_space_write_4(sc->sc_iot, sc->sc_ioh,
                                                  SACOM_CR3, sc->sc_cr3);
                        }
                }
                COM_UNLOCK(sc);
                splx(s);
        }
}

static inline void
sacom_txsoft(struct sacom_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 inline void
sacom_stsoft(struct sacom_softc *sc, struct tty *tp)
{
}

void
sacomsoft(void *arg)
{
        struct sacom_softc *sc = arg;
        struct tty *tp;

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

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

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

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

int
sacomintr(void *arg)
{
        struct sacom_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 sr0, sr1;

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

        COM_LOCK(sc);
        sr0 = bus_space_read_4(iot, ioh, SACOM_SR0);
        if (!sr0) {
                COM_UNLOCK(sc);
                return 0;
        }
        if (ISSET(sr0, SR0_EIF))
                /* XXX silently discard error bits */
                bus_space_read_4(iot, ioh, SACOM_DR);
        if (ISSET(sr0, SR0_RBB))
                bus_space_write_4(iot, ioh, SACOM_SR0, SR0_RBB);
        if (ISSET(sr0, SR0_REB)) {
                bus_space_write_4(iot, ioh, SACOM_SR0, SR0_REB);
#if defined(DDB) || defined(KGDB)
#ifndef DDB_BREAK_CHAR
                if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
                        console_debugger();
                }
#endif
#endif /* DDB || KGDB */
        }


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

        sr1 = bus_space_read_4(iot, ioh, SACOM_SR1);
        if (ISSET(sr0, SR0_RFS | SR0_RID)) {
                if (!ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
                        while (cc > 0) {
                                if (!ISSET(sr1, SR1_RNE)) {
                                        bus_space_write_4(iot, ioh, SACOM_SR0,
                                                          SR0_RID);
                                        break;
                                }
                                put[0] = bus_space_read_4(iot, ioh, SACOM_DR);
                                put[1] = sr1;
#if defined(DDB) && defined(DDB_BREAK_CHAR)
                                if (put[0] == DDB_BREAK_CHAR &&
                                    ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
                                        console_debugger();

                                        sr1 = bus_space_read_4(iot, ioh, SACOM_SR1);
                                        continue;
                                }
#endif
                                put += 2;
                                if (put >= end)
                                        put = sc->sc_rbuf;
                                cc--;

                                sr1 = bus_space_read_4(iot, ioh, SACOM_SR1);
                        }

                        /*
                         * 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;

                        /* XXX do RX hardware flow control */

                        /*
                         * 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_cr3, CR3_RIE);
                                bus_space_write_4(iot, ioh, SACOM_CR3,
                                                  sc->sc_cr3);
                        }
                } else {
#ifdef DIAGNOSTIC
                        panic("sacomintr: we shouldn't reach here");
#endif
                        CLR(sc->sc_cr3, CR3_RIE);
                        bus_space_write_4(iot, ioh, SACOM_CR3, sc->sc_cr3);
                }
        }

        /*
         * 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.
         */
        sr0 = bus_space_read_4(iot, ioh, SACOM_SR0);
        if (ISSET(sr0, SR0_TFS)) {
                /*
                 * If we've delayed a parameter change, do it now, and restart
                 * output.
                 * XXX sacom_loadchannelregs() waits TX completion,
                 * XXX resulting in ~0.1s hang (300bps, 4 bytes) in worst case
                 */
                if (sc->sc_heldchange) {
                        sacom_loadchannelregs(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) {
                        sacom_filltx(sc);
                } else {
                        /* Disable transmit completion interrupts if necessary. */
                        if (ISSET(sc->sc_cr3, CR3_TIE)) {
                                CLR(sc->sc_cr3, CR3_TIE);
                                bus_space_write_4(iot, ioh, SACOM_CR3,
                                                  sc->sc_cr3);
                        }
                        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;
}

static void
sacom_j720_init(device_t parent, device_t self)
{
        struct sa11x0_softc *sasc;

        sasc = device_private(parent);

        /* XXX  this should be done at sc->enable function */
        bus_space_write_4(sasc->sc_iot, sasc->sc_gpioh,
            SAGPIO_PCR, 0xa0000);
        bus_space_write_4(sasc->sc_iot, sasc->sc_gpioh,
            SAGPIO_PSR, 0x100);
}

/* Initialization for serial console */
int
sacominit(bus_space_tag_t iot, bus_addr_t iobase, int baud, tcflag_t cflag,
    bus_space_handle_t *iohp)
{
        int brd, cr0;

        if (bus_space_map(iot, iobase, SACOM_NPORTS, 0, iohp))
                aprint_normal("register map failed\n");

        /* wait for the Tx queue to drain and disable the UART */
        while (bus_space_read_4(iot, *iohp, SACOM_SR1) & SR1_TBY)
                continue;
        bus_space_write_4(iot, *iohp, SACOM_CR3, 0);

        cr0  = cflag2cr0(cflag);
        bus_space_write_4(iot, *iohp, SACOM_CR0, cr0);

        brd = SACOMSPEED(baud);
        sacomconsrate = baud;
        sacomconsaddr = iobase;
        sacomconscflag = cflag;
        /* XXX assumes little endian */
        bus_space_write_4(iot, *iohp, SACOM_CR1, brd >> 8);
        bus_space_write_4(iot, *iohp, SACOM_CR2, brd & 0xff);

        /* enable the UART */
        bus_space_write_4(iot, *iohp, SACOM_CR3, CR3_RXE | CR3_TXE);

        return 0;
}

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

void
sacomcninit(struct consdev *cp)
{
        if (cp == NULL) {
                /* XXX cp == NULL means that MMU is disabled. */
                sacomconsioh = SACOM3_BASE;
                sacomconstag = &sa11x0_bs_tag;
                cn_tab = &sacomcons;
                return;
        }

        if (sacominit(&sa11x0_bs_tag, CONADDR, CONSPEED,
                          CONMODE, &sacomconsioh))
                panic("can't init serial console @%x", CONADDR);
        cn_tab = &sacomcons;
        sacomconstag = &sa11x0_bs_tag;
}

int
sacomcngetc(dev_t dev)
{
        int c, s;

        s = spltty();   /* XXX do we need this? */

        while (!(bus_space_read_4(sacomconstag, sacomconsioh, SACOM_SR1)
                 & SR1_RNE)) {
#if defined(DDB) || defined(KGDB)
#ifndef DDB_BREAK_CHAR
                u_int sr0;

                sr0 = bus_space_read_4(sacomconstag, sacomconsioh, SACOM_SR0);
                if (ISSET(sr0, SR0_RBB))
                        bus_space_write_4(sacomconstag, sacomconsioh,
                                          SACOM_SR0, SR0_RBB);
                if (ISSET(sr0, SR0_REB)) {
                        bus_space_write_4(sacomconstag, sacomconsioh,
                                          SACOM_SR0, SR0_REB);
                        if (db_active == 0)
                                console_debugger();
                }
#endif
#endif /* DDB || KGDB */
        }

        c = bus_space_read_4(sacomconstag, sacomconsioh, SACOM_DR);
        c &= 0xff;
        splx(s);

        return c;
}

void
sacomcnputc(dev_t dev, int c)
{
        int s;

        s = spltty();   /* XXX do we need this? */

        while (!(bus_space_read_4(sacomconstag, sacomconsioh, SACOM_SR1)
            & SR1_TNF))
                continue;

        bus_space_write_4(sacomconstag, sacomconsioh, SACOM_DR, c);
        splx(s);
}

void
sacomcnpollc(dev_t dev, int on)
{

}

#if 0
#ifdef DEBUG
int
sacomcncharpoll(void)
{
        int c;

        if (!(bus_space_read_4(sacomconstag, sacomconsioh, SACOM_SR1)
                 & SR1_RNE))
                return -1;

        c = bus_space_read_4(sacomconstag, sacomconsioh, SACOM_DR);
        c &= 0xff;

        return c;
}
#endif
#endif

/* helper function to identify the com ports used by
 console or KGDB (and not yet autoconf attached) */
int
sacom_is_console(bus_space_tag_t iot, bus_addr_t iobase,
    bus_space_handle_t *ioh)
{
        bus_space_handle_t help;

        if (!sacomconsattached &&
            iot == sacomconstag && iobase == sacomconsaddr)
                help = sacomconsioh;
        else
                return 0;

        if (ioh)
                *ioh = help;
        return 1;
}