/*      $NetBSD: clpscom.c,v 1.11 2023/09/01 08:53:52 andvar Exp $      */
/*
 * Copyright (c) 2013 KIYOHARA Takashi
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: clpscom.c,v 1.11 2023/09/01 08:53:52 andvar Exp $");

#include "rnd.h"

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/device.h>
#include <sys/errno.h>
#include <sys/fcntl.h>
#include <sys/intr.h>
#include <sys/kauth.h>
#include <sys/lwp.h>
#include <sys/kmem.h>
#include <sys/systm.h>
#include <sys/termios.h>
#include <sys/tty.h>
#include <sys/types.h>

#include <ddb/db_active.h>

#include <arm/clps711x/clps711xreg.h>
#include <arm/clps711x/clpssocvar.h>

#include <dev/cons.h>

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

#include "ioconf.h"
#include "locators.h"

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

#define CLPSCOM_RING_SIZE       2048
#define UART_FIFO_SIZE          16

#define CLPSCOM_READ_CON(sc) \
        bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, PS711X_SYSCON)
#define CLPSCOM_WRITE_CON(sc, val) \
        bus_space_write_4((sc)->sc_iot, (sc)->sc_ioh, PS711X_SYSCON, (val))
#define CLPSCOM_READ_FLG(sc) \
        bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, PS711X_SYSFLG)
#define CLPSCOM_WRITE_FLG(sc, val) \
        bus_space_write_4((sc)->sc_iot, (sc)->sc_ioh, PS711X_SYSFLG, (val))
#define CLPSCOM_READ(sc) \
        bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, PS711X_UARTDR)
#define CLPSCOM_WRITE(sc, val) \
        bus_space_write_1((sc)->sc_iot, (sc)->sc_ioh, PS711X_UARTDR, (val))
#define CLPSCOM_WRITE_MULTI(sc, val, n) \
  bus_space_write_multi_1((sc)->sc_iot, (sc)->sc_ioh, PS711X_UARTDR, (val), (n))
#define CLPSCOM_READ_UBRLCR(sc) \
        bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, PS711X_UBRLCR)
#define CLPSCOM_WRITE_UBRLCR(sc, val) \
        bus_space_write_4((sc)->sc_iot, (sc)->sc_ioh, PS711X_UBRLCR, (val))

struct clpscom_softc {
        device_t sc_dev;
        bus_space_tag_t sc_iot;
        bus_space_handle_t sc_ioh;
        int sc_irq[3];
        void *sc_ih[3];
#define CLPSCOM_TXINT   0
#define CLPSCOM_RXINT   1
#define CLPSCOM_MSINT   2

        void *sc_si;

        struct tty *sc_tty;

        u_char *sc_tba;
        u_int sc_tbc;
        u_char *sc_rbuf;
        char *volatile sc_rbget;
        char *volatile sc_rbput;
        volatile int sc_rbavail;

#define CLPSCOM_MODEM_STATUS_MASK (SYSFLG_DCD | SYSFLG_DSR | SYSFLG_CTS)
        uint32_t sc_ms;
        uint32_t sc_ms_dcd;
        uint32_t sc_ms_cts;
        uint32_t sc_ms_mask;
        uint32_t sc_ms_delta;

        int sc_tx_stopped;

        int sc_tx_done;
        int sc_rx_ready;
        int sc_ms_changed;

        int sc_hwflags;
#define COM_HW_CONSOLE  (1 << 0)
#define COM_HW_DEV_OK   (1 << 1)
#define COM_HW_KGDB     (1 << 2)
        int sc_swflags;

#ifdef RND_COM
        krndsource_t rnd_source;
#endif
};

static int clpscom_match(device_t, cfdata_t, void *);
static void clpscom_attach(device_t, device_t, void *);

static int clpscom_txintr(void *);
static int clpscom_rxintr(void *);
static int clpscom_msintr(void *);
static void clpscom_soft(void *);

static void clpscom_start(struct tty *);
static int clpscom_param(struct tty *, struct termios *);
static int clpscom_hwiflow(struct tty *, int);

dev_type_open(clpscomopen);
dev_type_close(clpscomclose);
dev_type_read(clpscomread);
dev_type_write(clpscomwrite);
dev_type_ioctl(clpscomioctl);
dev_type_stop(clpscomstop);
dev_type_tty(clpscomtty);
dev_type_poll(clpscompoll);

static void clpscom_iflush(struct clpscom_softc *);
static void clpscom_shutdown(struct clpscom_softc *);
static void clpscom_break(struct clpscom_softc *, int);
static int clpscom_to_tiocm(struct clpscom_softc *);

static void clpscom_rxsoft(struct clpscom_softc *, struct tty *);
static void clpscom_mssoft(struct clpscom_softc *, struct tty *);

static inline uint32_t clpscom_rate2ubrlcr(int);
static uint32_t clpscom_cflag2ubrlcr(tcflag_t);

static int clpscom_cngetc(dev_t);
static void clpscom_cnputc(dev_t, int);
static void clpscom_cnpollc(dev_t, int);

CFATTACH_DECL_NEW(clpscom, sizeof(struct clpscom_softc),
    clpscom_match, clpscom_attach, NULL, NULL);

const struct cdevsw clpscom_cdevsw = {
        .d_open = clpscomopen,
        .d_close = clpscomclose,
        .d_read = clpscomread,
        .d_write = clpscomwrite,
        .d_ioctl = clpscomioctl,
        .d_stop = clpscomstop,
        .d_tty = clpscomtty,
        .d_poll = clpscompoll,
        .d_mmap = nommap,
        .d_kqfilter = ttykqfilter,
        .d_discard = nodiscard,
        .d_flag = D_TTY
};

static struct cnm_state clpscom_cnm_state;
static vaddr_t clpscom_cnaddr = 0;
static int clpscom_cnrate;
static tcflag_t clpscom_cncflag;


/* ARGSUSED */
static int
clpscom_match(device_t parent, cfdata_t match, void *aux)
{

        return 1;
}

/* ARGSUSED */
static void
clpscom_attach(device_t parent, device_t self, void *aux)
{
        struct clpscom_softc *sc = device_private(self);
        struct clpssoc_attach_args *aa = aux;
        int i;

        aprint_naive("\n");
        aprint_normal("\n");

        sc->sc_dev = self;
        sc->sc_iot = aa->aa_iot;
        sc->sc_ioh = *aa->aa_ioh;
        for (i = 0; i < __arraycount(aa->aa_irq); i++) {
                sc->sc_irq[i] = aa->aa_irq[i];
                sc->sc_ih[i] = NULL;
        }

        if (clpscom_cnaddr != 0)
                SET(sc->sc_hwflags, COM_HW_CONSOLE);

        sc->sc_tty = tty_alloc();
        sc->sc_tty->t_oproc = clpscom_start;
        sc->sc_tty->t_param = clpscom_param;
        sc->sc_tty->t_hwiflow = clpscom_hwiflow;

        sc->sc_tbc = 0;
        sc->sc_rbuf = kmem_alloc(CLPSCOM_RING_SIZE << 1, KM_SLEEP);
        sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
        sc->sc_rbavail = CLPSCOM_RING_SIZE;

        tty_attach(sc->sc_tty);

        if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
                int maj = cdevsw_lookup_major(&clpscom_cdevsw);

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

                aprint_normal_dev(self, "console\n");
        }

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

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

        SET(sc->sc_hwflags, COM_HW_DEV_OK);
}

static int
clpscom_txintr(void *arg)
{
        struct clpscom_softc *sc = arg;
        uint32_t sysflg;

        if (!device_is_active(sc->sc_dev))
                return 0;

        sysflg = CLPSCOM_READ_FLG(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.
         */

        if (!ISSET(sysflg, SYSFLG_UTXFF)) {
                /* Output the next chunk of the contiguous buffer, if any. */
                if (sc->sc_tbc > 0) {
                        while (sc->sc_tbc > 0 && !ISSET(sysflg, SYSFLG_UTXFF)) {
                                CLPSCOM_WRITE(sc, *sc->sc_tba);
                                sc->sc_tba++;
                                sc->sc_tbc--;
                                sysflg = CLPSCOM_READ_FLG(sc);
                        }
                } else if (!ISSET(sysflg, SYSFLG_UBUSY) &&
                                        sc->sc_ih[CLPSCOM_TXINT] != NULL) {
                        intr_disestablish(sc->sc_ih[CLPSCOM_TXINT]);
                        sc->sc_ih[CLPSCOM_TXINT] = NULL;
                        sc->sc_tx_done = 1;
                }
        }

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

        return 1;
}

static int
clpscom_rxintr(void *arg)
{
        struct clpscom_softc *sc = arg;
        int cc;
        uint32_t sysflg;
        uint16_t data;
        u_char *put;

        if (!device_is_active(sc->sc_dev))
                return 0;

        if (sc->sc_ih[CLPSCOM_RXINT] != NULL) {
                put = sc->sc_rbput;
                cc = sc->sc_rbavail;
                while (cc > 0) {
                        sysflg = CLPSCOM_READ_FLG(sc);
                        if (ISSET(sysflg, SYSFLG_URXFE))
                                break;
                        data = CLPSCOM_READ(sc);
                        cn_check_magic(sc->sc_tty->t_dev, data & 0xff,
                            clpscom_cnm_state);

                        put[0] = data & 0xff;
                        put[1] = (data >> 8) & 0xff;
                        put += 2;
                        if (put >= sc->sc_rbuf + (CLPSCOM_RING_SIZE << 1))
                                put = sc->sc_rbuf;
                        cc--;
                        sc->sc_rx_ready = 1;
                }

                /*
                 * 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;

                /*
                 * See if we are in danger of overflowing a buffer. If
                 * so, use hardware flow control to ease the pressure.
                 */

                /* but clpscom cannot. X-( */

                /*
                 * If we're out of space, disable receive interrupts
                 * until the queue has drained a bit.
                 */
                if (cc <= 0) {
                        intr_disestablish(sc->sc_ih[CLPSCOM_RXINT]);
                        sc->sc_ih[CLPSCOM_RXINT] = NULL;
                }
        }

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

        return 1;
}

static int
clpscom_msintr(void *arg)
{
        struct clpscom_softc *sc = arg;
        uint32_t ms, delta;

        if (!device_is_active(sc->sc_dev))
                return 0;

        if (sc->sc_ih[CLPSCOM_MSINT] != NULL) {
                ms = CLPSCOM_READ_FLG(sc) & CLPSCOM_MODEM_STATUS_MASK;
                delta = ms ^ sc->sc_ms;
                sc->sc_ms = ms;

                if (ISSET(delta, sc->sc_ms_mask)) {
                        SET(sc->sc_ms_delta, delta);

                        /*
                         * Stop output immediately if we lose the output
                         * flow control signal or carrier detect.
                         */
                        if (ISSET(~ms, sc->sc_ms_mask))
                                sc->sc_tbc = 0;
                        sc->sc_ms_changed = 1;
                }
        }
        bus_space_write_4(sc->sc_iot, sc->sc_ioh, PS711X_UMSEOI, 1);

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

        return 1;
}

static void
clpscom_soft(void *arg)
{
        struct clpscom_softc *sc = arg;
        struct tty *tp = sc->sc_tty;

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

        if (sc->sc_rx_ready) {
                sc->sc_rx_ready = 0;
                clpscom_rxsoft(sc, tp);
        }
        if (sc->sc_tx_done) {
                sc->sc_tx_done = 0;
                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);
        }
        if (sc->sc_ms_changed == 1) {
                sc->sc_ms_changed = 0;
                clpscom_mssoft(sc, tp);
        }
}

static void
clpscom_start(struct tty *tp)
{
        struct clpscom_softc *sc
                = device_lookup_private(&clpscom_cd, COMUNIT(tp->t_dev));
        int s, n;

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

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

        SET(tp->t_state, TS_BUSY);

        if (sc->sc_ih[CLPSCOM_TXINT] == NULL) {
                sc->sc_ih[CLPSCOM_TXINT] =
                    intr_establish(sc->sc_irq[CLPSCOM_TXINT], IPL_SERIAL, 0,
                    clpscom_txintr, sc);
                if (sc->sc_ih[CLPSCOM_TXINT] == NULL)
                        printf("%s: can't establish tx interrupt\n",
                            device_xname(sc->sc_dev));

                /* Output the first chunk of the contiguous buffer. */
                n = uimin(sc->sc_tbc, UART_FIFO_SIZE);
                CLPSCOM_WRITE_MULTI(sc, sc->sc_tba, n);
                sc->sc_tba += n;
                sc->sc_tbc -= n;
        }
out:
        splx(s);
        return;
}

static int
clpscom_param(struct tty *tp, struct termios *t)
{
        struct clpscom_softc *sc =
            device_lookup_private(&clpscom_cd, COMUNIT(tp->t_dev));
        int s;

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

        /*
         * 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_ms_dcd = 0;
        else
                sc->sc_ms_dcd = SYSFLG_DCD;
        /*
         * Set the flow control pins depending on the current flow control
         * mode.
         */
        if (ISSET(t->c_cflag, CRTSCTS)) {
                sc->sc_ms_cts = SYSFLG_CTS;
        } else if (ISSET(t->c_cflag, MDMBUF)) {
                /*
                 * For DTR/DCD flow control, make sure we don't toggle DTR for
                 * carrier detection.
                 */
                sc->sc_ms_cts = SYSFLG_DCD;
        } 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_ms_cts = 0;
        }
        sc->sc_ms_mask = sc->sc_ms_cts | sc->sc_ms_dcd;

        s = splserial();
        CLPSCOM_WRITE_UBRLCR(sc,
            UBRLCR_FIFOEN |
            clpscom_rate2ubrlcr(t->c_ospeed) |
            clpscom_cflag2ubrlcr(t->c_cflag));

        /* And copy to tty. */
        tp->t_ispeed = 0;
        tp->t_ospeed = t->c_ospeed;
        tp->t_cflag = t->c_cflag;
        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 by
         * explicit request.
         */
        (*tp->t_linesw->l_modem)(tp, ISSET(sc->sc_ms, SYSFLG_DCD));

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

        return 0;
}

static int
clpscom_hwiflow(struct tty *tp, int block)
{
        /* Nothing */
        return 0;
}

/* ARGSUSED */
int
clpscomopen(dev_t dev, int flag, int mode, struct lwp *l)
{
        struct clpscom_softc *sc;
        struct tty *tp;
        int error, s, s2;

        sc = device_lookup_private(&clpscom_cd, COMUNIT(dev));
        if (sc == NULL || !ISSET(sc->sc_hwflags, COM_HW_DEV_OK))
                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;

                /* Enable and turn on interrupt */
                CLPSCOM_WRITE_CON(sc, CLPSCOM_READ_CON(sc) | SYSCON_UARTEN);

                /* Fetch the current modem control status, needed later. */
                sc->sc_ms = CLPSCOM_READ_FLG(sc) & CLPSCOM_MODEM_STATUS_MASK;

                /*
                 * 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 = clpscom_cnrate;
                        t.c_cflag = clpscom_cncflag;
                } 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 pscom_param() we do something */
                tp->t_ospeed = 0;
                clpscom_param(tp, &t);
                tp->t_iflag = TTYDEF_IFLAG;
                tp->t_oflag = TTYDEF_OFLAG;
                tp->t_lflag = TTYDEF_LFLAG;
                ttychars(tp);
                ttsetwater(tp);

                s2 = splserial();

                /* Clear the input ring. */
                sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
                sc->sc_rbavail = CLPSCOM_RING_SIZE;
                clpscom_iflush(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.
                 */
                clpscom_shutdown(sc);

                /* Disable UART */
                if (!ISSET(sc->sc_hwflags, COM_HW_CONSOLE))
                        CLPSCOM_WRITE_CON(sc,
                            CLPSCOM_READ_CON(sc) & ~SYSCON_UARTEN);
        }

        return error;
}

/* ARGSUSED */
int
clpscomclose(dev_t dev, int flag, int mode, struct lwp *l)
{
        struct clpscom_softc *sc =
            device_lookup_private(&clpscom_cd, COMUNIT(dev));
        struct tty *tp = sc->sc_tty;

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

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

        if (!device_is_active(sc->sc_dev))
                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.
                 */
                clpscom_shutdown(sc);

                /* Disable UART */
                if (!ISSET(sc->sc_hwflags, COM_HW_CONSOLE))
                        CLPSCOM_WRITE_CON(sc,
                            CLPSCOM_READ_CON(sc) & ~SYSCON_UARTEN);
        }

        return 0;
}

int
clpscomread(dev_t dev, struct uio *uio, int flag)
{
        struct clpscom_softc *sc =
            device_lookup_private(&clpscom_cd, COMUNIT(dev));
        struct tty *tp = sc->sc_tty;

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

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

int
clpscomwrite(dev_t dev, struct uio *uio, int flag)
{
        struct clpscom_softc *sc =
            device_lookup_private(&clpscom_cd, COMUNIT(dev));
        struct tty *tp = sc->sc_tty;

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

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

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

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

        switch (cmd) {
        case TIOCSFLAGS:
                error = kauth_authorize_device_tty(l->l_cred,
                    KAUTH_DEVICE_TTY_PRIVSET, tp);
                break;
        default:
                break;
        }
        if (error)
                return error;

        s = splserial();
        error = 0;
        switch (cmd) {
        case TIOCSBRK:
                clpscom_break(sc, 1);
                break;

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

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

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

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

        default:
                error = EPASSTHROUGH;
                break;
        }
        splx(s);
        return error;
}

int
clpscompoll(dev_t dev, int events, struct lwp *l)
{
        struct clpscom_softc *sc =
            device_lookup_private(&clpscom_cd, COMUNIT(dev));
        struct tty *tp = sc->sc_tty;

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

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

struct tty *
clpscomtty(dev_t dev)
{
        struct clpscom_softc *sc =
            device_lookup_private(&clpscom_cd, COMUNIT(dev));

        return sc->sc_tty;
}

void
clpscomstop(struct tty *tp, int flag)
{
        int s;

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


static void
clpscom_iflush(struct clpscom_softc *sc)
{
        int timo;

        timo = 50000;
        while ((CLPSCOM_READ_FLG(sc) & SYSFLG_URXFE) == 0
            && timo--)
                CLPSCOM_READ(sc);
        if (timo == 0)
                printf("%s: iflush timeout\n", device_xname(sc->sc_dev));
}

static void
clpscom_shutdown(struct clpscom_softc *sc)
{
        int s;

        s = splserial();

        /* Turn off all interrupts */
        if (sc->sc_ih[CLPSCOM_TXINT] != NULL)
                intr_disestablish(sc->sc_ih[CLPSCOM_TXINT]);
        sc->sc_ih[CLPSCOM_TXINT] = NULL;
        if (sc->sc_ih[CLPSCOM_RXINT] != NULL)
                intr_disestablish(sc->sc_ih[CLPSCOM_RXINT]);
        sc->sc_ih[CLPSCOM_RXINT] = NULL;
        if (sc->sc_ih[CLPSCOM_MSINT] != NULL)
                intr_disestablish(sc->sc_ih[CLPSCOM_MSINT]);
        sc->sc_ih[CLPSCOM_MSINT] = NULL;

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

        splx(s);
}

static void
clpscom_break(struct clpscom_softc *sc, int onoff)
{
        int s;
        uint8_t ubrlcr;

        s = splserial();
        ubrlcr = CLPSCOM_READ_UBRLCR(sc);
        if (onoff)
                SET(ubrlcr, UBRLCR_BREAK);
        else
                CLR(ubrlcr, UBRLCR_BREAK);
        CLPSCOM_WRITE_UBRLCR(sc, ubrlcr);
        splx(s);
}

static int
clpscom_to_tiocm(struct clpscom_softc *sc)
{
        uint32_t combits;
        int ttybits = 0;

        combits = sc->sc_ms;
        if (ISSET(combits, SYSFLG_DCD))
                SET(ttybits, TIOCM_CD);
        if (ISSET(combits, SYSFLG_CTS))
                SET(ttybits, TIOCM_CTS);
        if (ISSET(combits, SYSFLG_DSR))
                SET(ttybits, TIOCM_DSR);

        return ttybits;
}

static void
clpscom_rxsoft(struct clpscom_softc *sc, struct tty *tp)
{
        int code, s;
        u_int cc, scc;
        u_char sts, *get;

        get = sc->sc_rbget;
        scc = cc = CLPSCOM_RING_SIZE - sc->sc_rbavail;
        while (cc) {
                code = get[0];
                sts = get[1];
                if (ISSET(sts, UARTDR_FRMERR | UARTDR_PARERR | UARTDR_OVERR)) {
                        if (ISSET(sts, (UARTDR_FRMERR)))
                                SET(code, TTY_FE);
                        if (ISSET(sts, UARTDR_PARERR))
                                SET(code, TTY_PE);
                        if (ISSET(sts, UARTDR_OVERR))
                                ;               /* XXXXX: Overrun */
                }
                if ((*tp->t_linesw->l_rint)(code, tp) == -1) {
                        /*
                         * The line discipline's buffer is out of space.
                         */
                        /*
                         * 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 >= sc->sc_rbuf + (CLPSCOM_RING_SIZE << 1))
                                get -= (CLPSCOM_RING_SIZE << 1);
                        cc = 0;
                        break;
                }
                get += 2;
                if (get >= sc->sc_rbuf + (CLPSCOM_RING_SIZE << 1))
                        get = sc->sc_rbuf;
                cc--;
        }

        if (cc != scc) {
                sc->sc_rbget = get;
                s = splserial();
                
                cc = sc->sc_rbavail += scc - cc;
                /* Buffers should be ok again, release possible block. */
                if (cc >= 1) {
                        if (sc->sc_ih[CLPSCOM_RXINT] == NULL) {
                                sc->sc_ih[CLPSCOM_RXINT] =
                                    intr_establish(sc->sc_irq[CLPSCOM_RXINT],
                                    IPL_SERIAL, 0, clpscom_rxintr, sc);
                                if (sc->sc_ih[CLPSCOM_RXINT] == NULL)
                                        printf("%s: can't establish"
                                            " rx interrupt\n",
                                            device_xname(sc->sc_dev));
                        }
                        if (sc->sc_ih[CLPSCOM_MSINT] == NULL) {
                                sc->sc_ih[CLPSCOM_MSINT] =
                                    intr_establish(sc->sc_irq[CLPSCOM_MSINT],
                                    IPL_SERIAL, 0, clpscom_msintr, sc);
                                if (sc->sc_ih[CLPSCOM_MSINT] == NULL)
                                        printf("%s: can't establish"
                                            " ms interrupt\n",
                                            device_xname(sc->sc_dev));
                        }
                }
                splx(s);
        }
}

static void
clpscom_mssoft(struct clpscom_softc *sc, struct tty *tp)
{
        uint32_t ms, delta;

        ms = sc->sc_ms;
        delta = sc->sc_ms_delta;
        sc->sc_ms_delta = 0;

        if (ISSET(delta, sc->sc_ms_dcd))
                /*
                 * Inform the tty layer that carrier detect changed.
                 */
                (void) (*tp->t_linesw->l_modem)(tp, ISSET(ms, SYSFLG_DCD));

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

static inline uint32_t
clpscom_rate2ubrlcr(int rate)
{

        return 230400 / rate - 1;
}

static uint32_t
clpscom_cflag2ubrlcr(tcflag_t cflag)
{
        int32_t ubrlcr = 0;

        switch (cflag & CSIZE) {
        case CS5: SET(ubrlcr, UBRLCR_WRDLEN_5B); break;
        case CS6: SET(ubrlcr, UBRLCR_WRDLEN_6B); break;
        case CS7: SET(ubrlcr, UBRLCR_WRDLEN_7B); break;
        case CS8: SET(ubrlcr, UBRLCR_WRDLEN_8B); break;
        default:  SET(ubrlcr, UBRLCR_WRDLEN_8B); break;
        }
        if (cflag & CSTOPB)
                SET(ubrlcr, UBRLCR_XSTOP);
        if (cflag & PARENB) {
                SET(ubrlcr, (UBRLCR_PRTEN | UBRLCR_EVENPRT));
                if (cflag & PARODD)
                        CLR(ubrlcr, UBRLCR_EVENPRT);
        }
        return ubrlcr;
}

#define CLPSCOM_CNREAD() \
        (*(volatile uint32_t *)(clpscom_cnaddr + PS711X_UARTDR))
#define CLPSCOM_CNWRITE(val) \
        (*(volatile uint8_t *)(clpscom_cnaddr + PS711X_UARTDR) = val)
#define CLPSCOM_CNSTATUS() \
        (*(volatile uint32_t *)(clpscom_cnaddr + PS711X_SYSFLG))

static struct consdev clpscomcons = {
        NULL, NULL, clpscom_cngetc, clpscom_cnputc, clpscom_cnpollc,
        NULL, NULL, NULL, NODEV, CN_NORMAL
};

int
clpscom_cnattach(vaddr_t addr, int rate, tcflag_t cflag)
{

        clpscom_cnaddr = addr;
        clpscom_cnrate = rate;
        clpscom_cncflag = cflag;
        *(volatile uint32_t *)(clpscom_cnaddr + PS711X_SYSFLG) |= SYSCON_UARTEN;
        *(volatile uint32_t *)(clpscom_cnaddr + PS711X_UBRLCR) =
            UBRLCR_FIFOEN |
            clpscom_cflag2ubrlcr(cflag) |
            clpscom_rate2ubrlcr(rate);

        cn_tab = &clpscomcons;
        cn_init_magic(&clpscom_cnm_state);
        cn_set_magic("\047\001");       /* default magic is BREAK */

        return 0;
}

/* ARGSUSED */
static int
clpscom_cngetc(dev_t dev)
{
        int s = splserial();
        char ch;

        while (CLPSCOM_CNSTATUS() & SYSFLG_URXFE);

        ch = CLPSCOM_CNREAD();

        if (!db_active)
                cn_check_magic(dev, ch, clpscom_cnm_state);

        splx(s);
        return ch;
}

/* ARGSUSED */
static void
clpscom_cnputc(dev_t dev, int c)
{
        int s = splserial();

        while (CLPSCOM_CNSTATUS() & SYSFLG_UTXFF);

        CLPSCOM_CNWRITE(c);

        /* Make sure output. */
        while (CLPSCOM_CNSTATUS() & SYSFLG_UBUSY);

        splx(s);
}

/* ARGSUSED */
static void
clpscom_cnpollc(dev_t dev, int on)
{
        /* Nothing */
}