sys/arch/sh3/dev/scif.c

root/sys/arch/sh3/dev/scif.c
/*      $NetBSD: scif.c,v 1.70 2023/09/16 15:42:01 andvar Exp $ */

/*-
 * Copyright (C) 1999 T.Horiuchi and SAITOH Masanobu.  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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*-
 * Copyright (c) 1998, 1999 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * 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
 */

/*
 * SH internal serial driver
 *
 * This code is derived from both z8530tty.c and com.c
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: scif.c,v 1.70 2023/09/16 15:42:01 andvar Exp $");

#include "opt_kgdb.h"
#include "opt_scif.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/tty.h>
#include <sys/proc.h>
#include <sys/conf.h>
#include <sys/file.h>
#include <sys/syslog.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <sys/kmem.h>
#include <sys/kgdb.h>
#include <sys/kauth.h>
#include <sys/intr.h>

#include <dev/cons.h>

#include <sh3/clock.h>
#include <sh3/exception.h>
#include <sh3/scifreg.h>

#include <sh3/dev/scifvar.h>

#include "locators.h"


struct scif_softc {
        device_t sc_dev;

        struct tty *sc_tty;
        void *sc_si;

        callout_t sc_diag_ch;

#if 0
        bus_space_tag_t sc_iot;         /* ISA i/o space identifier */
        bus_space_handle_t   sc_ioh;    /* ISA io handle */

        int sc_drq;

        int sc_frequency;
#endif

        u_int sc_overflows,
              sc_floods,
              sc_errors;                /* number of retries so far */
        u_char sc_status[7];            /* copy of registers */

        int sc_hwflags;
        int sc_swflags;
        u_int sc_fifolen;

        u_int sc_r_hiwat,
              sc_r_lowat;
        u_char *volatile sc_rbget,
               *volatile sc_rbput;
        volatile u_int sc_rbavail;
        u_char *sc_rbuf,
               *sc_ebuf;

        u_char *sc_tba;                 /* transmit buffer address */
        u_int sc_tbc,                   /* transmit byte count */
              sc_heldtbc;

        volatile u_char sc_rx_flags,
#define RX_TTY_BLOCKED          0x01
#define RX_TTY_OVERFLOWED       0x02
#define RX_IBUF_BLOCKED         0x04
#define RX_IBUF_OVERFLOWED      0x08
#define RX_ANY_BLOCK            0x0f
                        sc_tx_busy,     /* working on an output chunk */
                        sc_tx_done,     /* done with one output chunk */
                        sc_tx_stopped,  /* H/W level stop (lost CTS) */
                        sc_st_check,    /* got a status interrupt */
                        sc_rx_ready;

        volatile u_char sc_heldchange;
};

#ifdef SCIF_DEBUG
int scif_debug = 1;
#define DPRINTF(x)      if (scif_debug) printf x
#else
#define DPRINTF(x)
#endif

static int scif_match(device_t, cfdata_t, void *);
static void scif_attach(device_t, device_t, void *);

CFATTACH_DECL_NEW(scif, sizeof(struct scif_softc),
    scif_match, scif_attach, NULL, NULL);

static int scif_attached = 0;   /* XXX: FIXME: don't limit to just one! */

extern struct cfdriver scif_cd;

#define SCIFUNIT(x)     TTUNIT(x)
#define SCIFDIALOUT(x)  TTDIALOUT(x)


/* console */
dev_type_cnprobe(scifcnprobe);
dev_type_cninit(scifcninit);
dev_type_cngetc(scifcngetc);
dev_type_cnputc(scifcnputc);


/* cdevsw */
dev_type_open(scifopen);
dev_type_close(scifclose);
dev_type_read(scifread);
dev_type_write(scifwrite);
dev_type_ioctl(scifioctl);
dev_type_stop(scifstop);
dev_type_tty(sciftty);
dev_type_poll(scifpoll);

const struct cdevsw scif_cdevsw = {
        .d_open = scifopen,
        .d_close = scifclose,
        .d_read = scifread,
        .d_write = scifwrite,
        .d_ioctl = scifioctl,
        .d_stop = scifstop,
        .d_tty = sciftty,
        .d_poll = scifpoll,
        .d_mmap = nommap,
        .d_kqfilter = ttykqfilter,
        .d_discard = nodiscard,
        .d_flag = D_TTY
};

#ifndef SCIFCONSOLE
#define SCIFCONSOLE     0
#endif
int scifconsole = SCIFCONSOLE;  /* patchable */

/* struct tty */
static void scifstart(struct tty *);
static int scifparam(struct tty *, struct termios *);


void InitializeScif (unsigned int);
int ScifErrCheck(void);
void scif_putc(unsigned char);
unsigned char scif_getc(void);

static int scifintr(void *);
static void scifsoft(void *);
static void scif_rxsoft(struct scif_softc *, struct tty *);
static void scif_txsoft(struct scif_softc *, struct tty *);
#if 0
static void scif_stsoft(struct scif_softc *, struct tty *);
#endif
static void scif_schedrx(struct scif_softc *);
static void scifdiag(void *);

static void scif_break(struct scif_softc *, int);
static void scif_iflush(struct scif_softc *);


/* Hardware flag masks (sc_hwflags) */
#define SCIF_HW_NOIEN   0x01
#define SCIF_HW_FIFO    0x02
#define SCIF_HW_FLOW    0x08
#define SCIF_HW_DEV_OK  0x20
#define SCIF_HW_CONSOLE 0x40
#define SCIF_HW_KGDB    0x80


/* Buffer size for character buffer */
#define SCIF_RING_SIZE  2048
static unsigned int scif_rbuf_size = SCIF_RING_SIZE;

/* Stop input when 3/4 of the ring is full; restart when only 1/4 is full. */
static unsigned int scif_rbuf_hiwat = (SCIF_RING_SIZE * 1) / 4;
static unsigned int scif_rbuf_lowat = (SCIF_RING_SIZE * 3) / 4;


#ifdef SCIFCN_SPEED
unsigned int scifcn_speed = SCIFCN_SPEED;
#else
unsigned int scifcn_speed = 9600;
#endif

#define CONMODE ((TTYDEF_CFLAG & ~(CSIZE | CSTOPB | PARENB)) | CS8) /* 8N1 */
int scifconscflag = CONMODE;

static int scifisconsole = 0;

#ifdef KGDB
static int kgdb_attached = 0;
#endif


#define divrnd(n, q)    (((n)*2/(q)+1)/2)       /* divide and round off */


/* XXX: uwe
 * Prepare for bus_spacification.  The difference in access widths is
 * still handled by the magic definitions in scifreg.h
 */
#define scif_smr_read()         SHREG_SCSMR2
#define scif_smr_write(v)       (SHREG_SCSMR2 = (v))

#define scif_brr_read()         SHREG_SCBRR2
#define scif_brr_write(v)       (SHREG_SCBRR2 = (v))

#define scif_scr_read()         SHREG_SCSCR2
#define scif_scr_write(v)       (SHREG_SCSCR2 = (v))

#define scif_ftdr_write(v)      (SHREG_SCFTDR2 = (v))

#define scif_ssr_read()         SHREG_SCSSR2
#define scif_ssr_write(v)       (SHREG_SCSSR2 = (v))

#define scif_frdr_read()        SHREG_SCFRDR2

#define scif_fcr_read()         SHREG_SCFCR2
#define scif_fcr_write(v)       (SHREG_SCFCR2 = (v))

#define scif_fdr_read()         SHREG_SCFDR2

#ifdef SH4 /* additional registers in sh4 */

#define scif_sptr_read()        SHREG_SCSPTR2
#define scif_sptr_write(v)      (SHREG_SCSPTR2 = (v))

#define scif_lsr_read()         SHREG_SCLSR2
#define scif_lsr_write(v)       (SHREG_SCLSR2 = (v))

#endif /* SH4 */


void
InitializeScif(unsigned int bps)
{

        /* Initialize SCR */
        scif_scr_write(0x00);

#if 0
        scif_fcr_write(SCFCR2_TFRST | SCFCR2_RFRST | SCFCR2_MCE);
#else
        scif_fcr_write(SCFCR2_TFRST | SCFCR2_RFRST);
#endif
        /* Serial Mode Register */
        scif_smr_write(0x00);   /* 8bit,NonParity,Even,1Stop */

        /* Bit Rate Register */
        scif_brr_write(divrnd(sh_clock_get_pclock(), 32 * bps) - 1);

        /*
         * wait 2m Sec, because Send/Recv must begin 1 bit period after
         * BRR is set.
         */
        delay(2000);

#if 0
        scif_fcr_write(FIFO_RCV_TRIGGER_14 | FIFO_XMT_TRIGGER_1 | SCFCR2_MCE);
#else
        scif_fcr_write(FIFO_RCV_TRIGGER_14 | FIFO_XMT_TRIGGER_1);
#endif

        /* Send permission, Receive permission ON */
        scif_scr_write(SCSCR2_TE | SCSCR2_RE);

        /* Serial Status Register */
        scif_ssr_write(scif_ssr_read() & SCSSR2_TDFE); /* Clear Status */
}

int
ScifErrCheck(void)
{

        return (scif_ssr_read() & (SCSSR2_ER | SCSSR2_FER | SCSSR2_PER));
}

void
scif_putc(unsigned char c)
{

        /* wait for ready */
        while ((scif_fdr_read() & SCFDR2_TXCNT) == SCFDR2_TXF_FULL)
                continue;

        /* write send data to send register */
        scif_ftdr_write(c);

        /* clear ready flag */
        scif_ssr_write(scif_ssr_read() & ~(SCSSR2_TDFE | SCSSR2_TEND));
}

unsigned char
scif_getc(void)
{
        unsigned char c, err_c;
#ifdef SH4
        unsigned short err_c2 = 0; /* XXXGCC: -Wuninitialized */
#endif

        for (;;) {
                /* wait for ready */
                while ((scif_fdr_read() & SCFDR2_RECVCNT) == 0)
                        continue;

                c = scif_frdr_read();
                err_c = scif_ssr_read();
                scif_ssr_write(scif_ssr_read()
                        & ~(SCSSR2_ER | SCSSR2_BRK | SCSSR2_RDF | SCSSR2_DR));
#ifdef SH4
                if (CPU_IS_SH4) {
                        err_c2 = scif_lsr_read();
                        scif_lsr_write(scif_lsr_read() & ~SCLSR2_ORER);
                }
#endif
                if ((err_c & (SCSSR2_ER | SCSSR2_BRK | SCSSR2_FER
                    | SCSSR2_PER)) == 0)
                {
#ifdef SH4
                        if (CPU_IS_SH4 && ((err_c2 & SCLSR2_ORER) == 0))
#endif
                        return(c);
                }
        }

}

static int
scif_match(device_t parent, cfdata_t cfp, void *aux)
{

        if (scif_attached)
                return 0;

        if (strcmp(cfp->cf_name, "scif") != 0)
                return 0;

        return 1;
}

static void
scif_attach(device_t parent, device_t self, void *aux)
{
        struct scif_softc *sc;
        struct tty *tp;

        sc = device_private(self);
        sc->sc_dev = self;

        scif_attached = 1;

        sc->sc_hwflags = 0;     /* XXX */
        sc->sc_swflags = 0;     /* XXX */
        sc->sc_fifolen = 16;

        aprint_normal("\n");
        if (scifisconsole) {
                aprint_naive(" (console)\n");
                aprint_normal_dev(self, "console\n");
                SET(sc->sc_hwflags, SCIF_HW_CONSOLE);
                SET(sc->sc_swflags, TIOCFLAG_SOFTCAR);
        }
#ifdef KGDB
        else if (kgdb_attached) {
                aprint_naive(" (kgdb)\n");
                aprint_normal_dev(self, "kgdb\n");
                SET(sc->sc_hwflags, SCIF_HW_KGDB);
                SET(sc->sc_swflags, TIOCFLAG_SOFTCAR);
        }
#endif
        else {
                aprint_naive("\n");
                InitializeScif(9600); /* XXX */
        }

        callout_init(&sc->sc_diag_ch, 0);
#ifdef SH4
        intc_intr_establish(SH4_INTEVT_SCIF_ERI, IST_LEVEL, IPL_SERIAL,
            scifintr, sc);
        intc_intr_establish(SH4_INTEVT_SCIF_RXI, IST_LEVEL, IPL_SERIAL,
            scifintr, sc);
        intc_intr_establish(SH4_INTEVT_SCIF_BRI, IST_LEVEL, IPL_SERIAL,
            scifintr, sc);
        intc_intr_establish(SH4_INTEVT_SCIF_TXI, IST_LEVEL, IPL_SERIAL,
            scifintr, sc);
#else
        intc_intr_establish(SH7709_INTEVT2_SCIF_ERI, IST_LEVEL, IPL_SERIAL,
            scifintr, sc);
        intc_intr_establish(SH7709_INTEVT2_SCIF_RXI, IST_LEVEL, IPL_SERIAL,
            scifintr, sc);
        intc_intr_establish(SH7709_INTEVT2_SCIF_BRI, IST_LEVEL, IPL_SERIAL,
            scifintr, sc);
        intc_intr_establish(SH7709_INTEVT2_SCIF_TXI, IST_LEVEL, IPL_SERIAL,
            scifintr, sc);
#endif

        sc->sc_si = softint_establish(SOFTINT_SERIAL, scifsoft, sc);
        SET(sc->sc_hwflags, SCIF_HW_DEV_OK);

        tp = tty_alloc();
        tp->t_oproc = scifstart;
        tp->t_param = scifparam;
        tp->t_hwiflow = NULL;

        sc->sc_tty = tp;
        sc->sc_rbuf = kmem_alloc(scif_rbuf_size << 1, KM_SLEEP);
        sc->sc_ebuf = sc->sc_rbuf + (scif_rbuf_size << 1);

        tty_attach(tp);

        /* XXX: TODO */
        if (!pmf_device_register(self, NULL, NULL))
                aprint_error_dev(self, "unable to establish power handler\n");
}

/*
 * Start or restart transmission.
 */
static void
scifstart(struct tty *tp)
{
        struct scif_softc *sc;
        int s;

        sc = device_lookup_private(&scif_cd, SCIFUNIT(tp->t_dev));

        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);
        sc->sc_tx_busy = 1;

        /* Enable transmit completion interrupts if necessary. */
        scif_scr_write(scif_scr_read() | SCSCR2_TIE | SCSCR2_RIE);

        /* Output the first chunk of the contiguous buffer. */
        {
                int n;
                int maxchars;
                int i;

                n = sc->sc_tbc;
                maxchars = sc->sc_fifolen
                        - ((scif_fdr_read() & SCFDR2_TXCNT) >> 8);
                if (n > maxchars)
                        n = maxchars;

                for (i = 0; i < n; i++) {
                        scif_putc(*(sc->sc_tba));
                        sc->sc_tba++;
                }
                sc->sc_tbc -= n;
        }
out:
        splx(s);
        return;
}

/*
 * Set SCIF tty parameters from termios.
 * XXX - Should just copy the whole termios after
 * making sure all the changes could be done.
 */
static int
scifparam(struct tty *tp, struct termios *t)
{
        struct scif_softc *sc;
        int ospeed = t->c_ospeed;
        int s;

        sc = device_lookup_private(&scif_cd, SCIFUNIT(tp->t_dev));
        if (!device_is_active(sc->sc_dev))
                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, SCIF_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 0
/* XXX (msaitoh) */
        lcr = ISSET(sc->sc_lcr, LCR_SBREAK) | cflag2lcr(t->c_cflag);
#endif

        s = splserial();

        /*
         * Set the flow control pins depending on the current flow control
         * mode.
         */
        if (ISSET(t->c_cflag, CRTSCTS)) {
                scif_fcr_write(scif_fcr_read() | SCFCR2_MCE);
        } else {
                scif_fcr_write(scif_fcr_read() & ~SCFCR2_MCE);
        }

        scif_brr_write(divrnd(sh_clock_get_pclock(), 32 * ospeed) -1);

        /*
         * Set the FIFO threshold based on the receive speed.
         *
         *  * If it's a low speed, it's probably a mouse or some other
         *    interactive device, so set the threshold low.
         *  * If it's a high speed, trim the trigger level down to prevent
         *    overflows.
         *  * Otherwise set it a bit higher.
         */
#if 0
/* XXX (msaitoh) */
        if (ISSET(sc->sc_hwflags, SCIF_HW_HAYESP))
                sc->sc_fifo = FIFO_DMA_MODE | FIFO_ENABLE | FIFO_TRIGGER_8;
        else if (ISSET(sc->sc_hwflags, SCIF_HW_FIFO))
                sc->sc_fifo = FIFO_ENABLE |
                    (t->c_ospeed <= 1200 ? FIFO_TRIGGER_1 :
                     t->c_ospeed <= 38400 ? FIFO_TRIGGER_8 : FIFO_TRIGGER_4);
        else
                sc->sc_fifo = 0;
#endif

        /* 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;
                }
#if 0
/* XXX (msaitoh) */
                else
                        scif_loadchannelregs(sc);
#endif
        }

        if (!ISSET(t->c_cflag, CHWFLOW)) {
                /* Disable the high water mark. */
                sc->sc_r_hiwat = 0;
                sc->sc_r_lowat = 0;
                if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
                        CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
                        scif_schedrx(sc);
                }
        } else {
                sc->sc_r_hiwat = scif_rbuf_hiwat;
                sc->sc_r_lowat = scif_rbuf_lowat;
        }

        splx(s);

        DPRINTF(("%s: scifparam\n", device_xname(sc->sc_dev)));

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

        return (0);
}

static void
scif_iflush(struct scif_softc *sc)
{
        int i;

        i = scif_fdr_read() & SCFDR2_RECVCNT;

        while (i > 0) {
                (void)scif_frdr_read();
                scif_ssr_write(scif_ssr_read() & ~(SCSSR2_RDF | SCSSR2_DR));
                i--;
        }
}

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

        sc = device_lookup_private(&scif_cd, SCIFUNIT(dev));
        if (sc == 0 || !ISSET(sc->sc_hwflags, SCIF_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, SCIF_HW_KGDB))
                return (EBUSY);
#endif /* KGDB */

        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();

                /* Turn on interrupts. */
                scif_scr_write(scif_scr_read() | SCSCR2_TIE | SCSCR2_RIE);

                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, SCIF_HW_CONSOLE)) {
                        t.c_ospeed = scifcn_speed;      /* XXX (msaitoh) */
                        t.c_cflag = scifconscflag;
                } 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 scifparam() will do something. */
                tp->t_ospeed = 0;
                (void) scifparam(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, and unblock. */
                sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
                sc->sc_rbavail = scif_rbuf_size;
                scif_iflush(sc);
                CLR(sc->sc_rx_flags, RX_ANY_BLOCK);
#if 0
/* XXX (msaitoh) */
                scif_hwiflow(sc);
#endif

                DPRINTF(("%s: scifopen\n", device_xname(sc->sc_dev)));

                splx(s2);
        }

        splx(s);

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

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

        return (0);

bad:

        return (error);
}

int
scifclose(dev_t dev, int flag, int mode, struct lwp *l)
{
        struct scif_softc *sc;
        struct tty *tp;

        sc = device_lookup_private(&scif_cd, SCIFUNIT(dev));
        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 (!device_is_active(sc->sc_dev))
                return (0);

        return (0);
}

int
scifread(dev_t dev, struct uio *uio, int flag)
{
        struct scif_softc *sc;
        struct tty *tp;

        sc = device_lookup_private(&scif_cd, SCIFUNIT(dev));
        tp = sc->sc_tty;

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

int
scifwrite(dev_t dev, struct uio *uio, int flag)
{
        struct scif_softc *sc;
        struct tty *tp;

        sc = device_lookup_private(&scif_cd, SCIFUNIT(dev));
        tp = sc->sc_tty;

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

int
scifpoll(dev_t dev, int events, struct lwp *l)
{
        struct scif_softc *sc;
        struct tty *tp;

        sc = device_lookup_private(&scif_cd, SCIFUNIT(dev));
        tp = sc->sc_tty;

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

struct tty *
sciftty(dev_t dev)
{
        struct scif_softc *sc;
        struct tty *tp;

        sc = device_lookup_private(&scif_cd, SCIFUNIT(dev));
        tp = sc->sc_tty;

        return (tp);
}

int
scifioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
{
        struct scif_softc *sc;
        struct tty *tp;
        int error;
        int s;

        sc = device_lookup_private(&scif_cd, SCIFUNIT(dev));
        if (!device_is_active(sc->sc_dev))
                return (EIO);

        tp = sc->sc_tty;
        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();

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

        case TIOCCBRK:
                scif_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;
        }

        splx(s);

        return (error);
}

static void
scif_schedrx(struct scif_softc *sc)
{

        sc->sc_rx_ready = 1;

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

static void
scif_break(struct scif_softc *sc, int onoff)
{

        if (onoff)
                scif_ssr_write(scif_ssr_read() & ~SCSSR2_TDFE);
        else
                scif_ssr_write(scif_ssr_read() | SCSSR2_TDFE);

#if 0   /* XXX */
        if (!sc->sc_heldchange) {
                if (sc->sc_tx_busy) {
                        sc->sc_heldtbc = sc->sc_tbc;
                        sc->sc_tbc = 0;
                        sc->sc_heldchange = 1;
                } else
                        scif_loadchannelregs(sc);
        }
#endif
}

/*
 * Stop output, e.g., for ^S or output flush.
 */
void
scifstop(struct tty *tp, int flag)
{
        struct scif_softc *sc;
        int s;

        sc = device_lookup_private(&scif_cd, SCIFUNIT(tp->t_dev));

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

static void
scifdiag(void *arg)
{
        struct scif_softc *sc = arg;
        int overflows, floods;
        int s;

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

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

static void
scif_rxsoft(struct scif_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 ssr2;
        int code;
        int s;

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

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

        while (cc) {
                code = get[0];
                ssr2 = get[1];
                if (ISSET(ssr2, SCSSR2_BRK | SCSSR2_FER | SCSSR2_PER)) {
                        if (ISSET(ssr2, SCSSR2_BRK | SCSSR2_FER))
                                SET(code, TTY_FE);
                        if (ISSET(ssr2, SCSSR2_PER))
                                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 -= scif_rbuf_size << 1;
                                cc = 0;
                        } else {
                                /*
                                 * Don't schedule any more receive processing
                                 * until the line discipline tells us there's
                                 * space available (through scifhwiflow()).
                                 * 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();
                cc = sc->sc_rbavail += scc - cc;
                /* Buffers should be ok again, release possible block. */
                if (cc >= sc->sc_r_lowat) {
                        if (ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
                                CLR(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
                                scif_scr_write(scif_scr_read() | SCSCR2_RIE);
                        }
#if 0
                        if (ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED)) {
                                CLR(sc->sc_rx_flags, RX_IBUF_BLOCKED);
                                scif_hwiflow(sc);
                        }
#endif
                }
                splx(s);
        }
}

static void
scif_txsoft(struct scif_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);
}

#if 0 /* XXX (msaitoh) */
static void
scif_stsoft(struct scif_softc *sc, struct tty *tp)
{
        u_char msr, delta;
        int s;

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

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

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

        DPRINTF(("%s: scif_stsoft\n", device_xname(sc->sc_dev)));
}
#endif /* 0 */

static void
scifsoft(void *arg)
{
        struct scif_softc *sc = arg;
        struct tty *tp;

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

        tp = sc->sc_tty;

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

#if 0
        if (sc->sc_st_check) {
                sc->sc_st_check = 0;
                scif_stsoft(sc, tp);
        }
#endif

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

static int
scifintr(void *arg)
{
        struct scif_softc *sc = arg;
        u_char *put, *end;
        u_int cc;
        u_short ssr2;
        int count;

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

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

        do {
                ssr2 = scif_ssr_read();
                if (ISSET(ssr2, SCSSR2_BRK)) {
                        scif_ssr_write(scif_ssr_read()
                                & ~(SCSSR2_ER | SCSSR2_BRK | SCSSR2_DR));
#ifdef DDB
                        if (ISSET(sc->sc_hwflags, SCIF_HW_CONSOLE)) {
                                console_debugger();
                        }
#endif /* DDB */
#ifdef KGDB
                        if (ISSET(sc->sc_hwflags, SCIF_HW_KGDB)) {
                                kgdb_connect(1);
                        }
#endif /* KGDB */
                }
                count = scif_fdr_read() & SCFDR2_RECVCNT;
                if (count != 0) {
                        for (;;) {
                                u_char c = scif_frdr_read();
                                u_char err = (u_char)(scif_ssr_read() & 0x00ff);

                                scif_ssr_write(scif_ssr_read()
                                    & ~(SCSSR2_ER | SCSSR2_RDF | SCSSR2_DR));
#ifdef SH4
                                if (CPU_IS_SH4)
                                        scif_lsr_write(scif_lsr_read()
                                                       & ~SCLSR2_ORER);
#endif
                                if ((cc > 0) && (count > 0)) {
                                        put[0] = c;
                                        put[1] = err;
                                        put += 2;
                                        if (put >= end)
                                                put = sc->sc_rbuf;
                                        cc--;
                                        count--;
                                } else
                                        break;
                        }

                        /*
                         * 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.
                         */
                        if (!ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED) &&
                            cc < sc->sc_r_hiwat) {
                                SET(sc->sc_rx_flags, RX_IBUF_BLOCKED);
#if 0
                                scif_hwiflow(sc);
#endif
                        }

                        /*
                         * 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);
                                scif_scr_write(scif_scr_read() & ~SCSCR2_RIE);
                        }
                } else {
                        if (scif_ssr_read() & (SCSSR2_RDF | SCSSR2_DR)) {
                                scif_scr_write(scif_scr_read()
                                               & ~(SCSCR2_TIE | SCSCR2_RIE));
                                delay(10);
                                scif_scr_write(scif_scr_read()
                                               | SCSCR2_TIE | SCSCR2_RIE);
                                continue;
                        }
                }
        } while (scif_ssr_read() & (SCSSR2_RDF | SCSSR2_DR));

#if 0
        msr = bus_space_read_1(iot, ioh, scif_msr);
        delta = msr ^ sc->sc_msr;
        sc->sc_msr = msr;
        if (ISSET(delta, sc->sc_msr_mask)) {
                SET(sc->sc_msr_delta, delta);

                /*
                 * Pulse-per-second clock signal on edge of DCD?
                 */
                if (ISSET(delta, sc->sc_ppsmask)) {
                        struct timeval tv;
                        if (ISSET(msr, sc->sc_ppsmask) ==
                            sc->sc_ppsassert) {
                                /* XXX nanotime() */
                                microtime(&tv);
                                TIMEVAL_TO_TIMESPEC(&tv,
                                                    &sc->ppsinfo.assert_timestamp);
                                if (sc->ppsparam.mode & PPS_OFFSETASSERT) {
                                        timespecadd(&sc->ppsinfo.assert_timestamp,
                                                    &sc->ppsparam.assert_offset,
                                                    &sc->ppsinfo.assert_timestamp);
                                        TIMESPEC_TO_TIMEVAL(&tv, &sc->ppsinfo.assert_timestamp);
                                }

#ifdef PPS_SYNC
                                if (sc->ppsparam.mode & PPS_HARDPPSONASSERT)
                                        hardpps(&tv, tv.tv_usec);
#endif
                                sc->ppsinfo.assert_sequence++;
                                sc->ppsinfo.current_mode =
                                        sc->ppsparam.mode;

                        } else if (ISSET(msr, sc->sc_ppsmask) ==
                                   sc->sc_ppsclear) {
                                /* XXX nanotime() */
                                microtime(&tv);
                                TIMEVAL_TO_TIMESPEC(&tv,
                                                    &sc->ppsinfo.clear_timestamp);
                                if (sc->ppsparam.mode & PPS_OFFSETCLEAR) {
                                        timespecadd(&sc->ppsinfo.clear_timestamp,
                                                    &sc->ppsparam.clear_offset,
                                                    &sc->ppsinfo.clear_timestamp);
                                        TIMESPEC_TO_TIMEVAL(&tv, &sc->ppsinfo.clear_timestamp);
                                }

#ifdef PPS_SYNC
                                if (sc->ppsparam.mode & PPS_HARDPPSONCLEAR)
                                        hardpps(&tv, tv.tv_usec);
#endif
                                sc->ppsinfo.clear_sequence++;
                                sc->ppsinfo.current_mode =
                                        sc->ppsparam.mode;
                        }
                }

                /*
                 * Stop output immediately if we lose the output
                 * flow control signal or carrier detect.
                 */
                if (ISSET(~msr, sc->sc_msr_mask)) {
                        sc->sc_tbc = 0;
                        sc->sc_heldtbc = 0;
                        DPRINTF(("%s: scifintr\n", device_xname(sc->sc_dev)));
                }

                sc->sc_st_check = 1;
        }
#endif

        /*
         * 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 (((scif_fdr_read() & SCFDR2_TXCNT) >> 8) != 16) { /* XXX (msaitoh) */
                /*
                 * If we've delayed a parameter change, do it now, and restart
                 * output.
                 */
                if (sc->sc_heldchange) {
                        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) {
                        int n;
                        int maxchars;
                        int i;

                        n = sc->sc_tbc;
                        maxchars = sc->sc_fifolen -
                                ((scif_fdr_read() & SCFDR2_TXCNT) >> 8);
                        if (n > maxchars)
                                n = maxchars;

                        for (i = 0; i < n; i++) {
                                scif_putc(*(sc->sc_tba));
                                sc->sc_tba++;
                        }
                        sc->sc_tbc -= n;
                } else {
                        /* Disable transmit completion interrupts if necessary. */
#if 0
                        if (ISSET(sc->sc_ier, IER_ETXRDY))
#endif
                                scif_scr_write(scif_scr_read() & ~SCSCR2_TIE);

                        if (sc->sc_tx_busy) {
                                sc->sc_tx_busy = 0;
                                sc->sc_tx_done = 1;
                        }
                }
        }

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

#ifdef RND_SCIF
        rnd_add_uint32(&sc->rnd_source, iir | lsr);
#endif

        return (1);
}

void
scifcnprobe(struct consdev *cp)
{
        int maj;

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

        /* Initialize required fields. */
        cp->cn_dev = makedev(maj, 0);
        if (scifconsole)
                cp->cn_pri = CN_REMOTE;
        else
                cp->cn_pri = CN_NORMAL;
}

void
scifcninit(struct consdev *cp)
{

        InitializeScif(scifcn_speed);
        scifisconsole = 1;
}

int
scifcngetc(dev_t dev)
{
        int c;
        int s;

        s = splserial();
        c = scif_getc();
        splx(s);

        return (c);
}

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

        s = splserial();
        scif_putc((u_char)c);
        splx(s);
}

#ifdef KGDB
int
scif_kgdb_init(void)
{

        if (strcmp(kgdb_devname, "scif") != 0)
                return (1);

        if (scifisconsole)
                return (1);     /* can't share with console */

        InitializeScif(kgdb_rate);

        kgdb_attach((int (*)(void *))scifcngetc,
            (void (*)(void *, int))scifcnputc, NULL);
        kgdb_dev = 123; /* unneeded, only to satisfy some tests */
        kgdb_attached = 1;

        return (0);
}
#endif /* KGDB */