/*      $NetBSD: sab.c,v 1.58 2022/10/26 23:59:36 riastradh Exp $       */
/*      $OpenBSD: sab.c,v 1.7 2002/04/08 17:49:42 jason Exp $   */

/*
 * Copyright (c) 2001 Jason L. Wright (jason@thought.net)
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Jason L. Wright
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * Effort sponsored in part by the Defense Advanced Research Projects
 * Agency (DARPA) and Air Force Research Laboratory, Air Force
 * Materiel Command, USAF, under agreement number F30602-01-2-0537.
 *
 */

/*
 * SAB82532 Dual UART driver
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sab.c,v 1.58 2022/10/26 23:59:36 riastradh Exp $");

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

#include <machine/autoconf.h>
#include <machine/openfirm.h>

#include <dev/cons.h>

#include <dev/ebus/ebusreg.h>
#include <dev/ebus/ebusvar.h>
#include <sparc64/dev/sab82532reg.h>

#include "locators.h"

#define SABUNIT(x)              TTUNIT(x)
#define SABDIALOUT(x)           TTDIALOUT(x)

#define SABTTY_RBUF_SIZE        1024    /* must be divisible by 2 */

struct sab_softc {
        device_t                sc_dev;
        struct intrhand *       sc_ih;
        bus_space_tag_t         sc_bt;
        bus_space_handle_t      sc_bh;
        struct sabtty_softc *   sc_child[SAB_NCHAN];
        u_int                   sc_nchild;
        void *                  sc_softintr;
        int                     sc_node;
};

struct sabtty_attach_args {
        u_int sbt_portno;
};

struct sabtty_softc {
        device_t                sc_dev;
        struct sab_softc *      sc_parent;
        bus_space_tag_t         sc_bt;
        bus_space_handle_t      sc_bh;
        struct tty *            sc_tty;
        u_int                   sc_portno;
        uint8_t                 sc_pvr_dtr, sc_pvr_dsr;
        uint8_t                 sc_imr0, sc_imr1;
        int                     sc_openflags;
        u_char *                sc_txp;
        int                     sc_txc;
        int                     sc_flags;
#define SABTTYF_STOP            0x0001
#define SABTTYF_DONE            0x0002
#define SABTTYF_RINGOVERFLOW    0x0004
#define SABTTYF_CDCHG           0x0008
#define SABTTYF_CONS_IN         0x0010
#define SABTTYF_CONS_OUT        0x0020
#define SABTTYF_TXDRAIN         0x0040
#define SABTTYF_DONTDDB         0x0080
#define SABTTYF_IS_RSC          0x0100
        uint8_t                 sc_rbuf[SABTTY_RBUF_SIZE];
        uint8_t                 *sc_rend, *sc_rput, *sc_rget;
        uint8_t                 sc_polling, sc_pollrfc;
};

struct sabtty_softc *sabtty_cons_input;
struct sabtty_softc *sabtty_cons_output;

#define SAB_READ(sc,r)          \
    bus_space_read_1((sc)->sc_bt, (sc)->sc_bh, (r))
#define SAB_WRITE(sc,r,v)       \
    bus_space_write_1((sc)->sc_bt, (sc)->sc_bh, (r), (v))
#define SAB_WRITE_BLOCK(sc,r,p,c)       \
    bus_space_write_region_1((sc)->sc_bt, (sc)->sc_bh, (r), (p), (c))

int sab_match(device_t, cfdata_t, void *);
void sab_attach(device_t, device_t, void *);
int sab_print(void *, const char *);
int sab_intr(void *);

void sab_softintr(void *);
void sab_cnputc(dev_t, int);
int sab_cngetc(dev_t);
void sab_cnpollc(dev_t, int);

int sabtty_match(device_t, cfdata_t, void *);
void sabtty_attach(device_t, device_t, void *);
void sabtty_start(struct tty *);
int sabtty_param(struct tty *, struct termios *);
int sabtty_intr(struct sabtty_softc *, int *);
void sabtty_softintr(struct sabtty_softc *);
int sabtty_mdmctrl(struct sabtty_softc *, int, int);
void sabtty_cec_wait(struct sabtty_softc *);
void sabtty_tec_wait(struct sabtty_softc *);
void sabtty_reset(struct sabtty_softc *);
void sabtty_flush(struct sabtty_softc *);
int sabtty_speed(int);
void sabtty_console_flags(struct sabtty_softc *);
void sabtty_cnpollc(struct sabtty_softc *, int);
bool sabtty_shutdown(device_t, int);
int sabttyparam(struct sabtty_softc *, struct tty *, struct termios *);

#ifdef KGDB
int sab_kgdb_check(struct sabtty_softc *);
void sab_kgdb_init(struct sabtty_softc *);
#endif

void sabtty_cnputc(struct sabtty_softc *, int);
int sabtty_cngetc(struct sabtty_softc *);

CFATTACH_DECL_NEW(sab, sizeof(struct sab_softc),
    sab_match, sab_attach, NULL, NULL);

extern struct cfdriver sab_cd;

CFATTACH_DECL_NEW(sabtty, sizeof(struct sabtty_softc),
    sabtty_match, sabtty_attach, NULL, NULL);

extern struct cfdriver sabtty_cd;

dev_type_open(sabopen);
dev_type_close(sabclose);
dev_type_read(sabread);
dev_type_write(sabwrite);
dev_type_ioctl(sabioctl);
dev_type_stop(sabstop);
dev_type_tty(sabtty);
dev_type_poll(sabpoll);

static struct cnm_state sabtty_cnm_state;

const struct cdevsw sabtty_cdevsw = {
        .d_open = sabopen,
        .d_close = sabclose,
        .d_read = sabread,
        .d_write = sabwrite,
        .d_ioctl = sabioctl,
        .d_stop = sabstop,
        .d_tty = sabtty,
        .d_poll = sabpoll,
        .d_mmap = nommap,
        .d_kqfilter = ttykqfilter,
        .d_discard = nodiscard,
        .d_flag = D_TTY
};

struct sabtty_rate {
        int baud;
        int n, m;
};

struct sabtty_rate sabtty_baudtable[] = {
        {      50,      35,     10 },
        {      75,      47,     9 },
        {     110,      32,     9 },
        {     134,      53,     8 },
        {     150,      47,     8 },
        {     200,      35,     8 },
        {     300,      47,     7 },
        {     600,      47,     6 },
        {    1200,      47,     5 },
        {    1800,      31,     5 },
        {    2400,      47,     4 },
        {    4800,      47,     3 },
        {    9600,      47,     2 },
        {   19200,      47,     1 },
        {   38400,      23,     1 },
        {   57600,      15,     1 },
        {  115200,       7,     1 },
        {  230400,       3,     1 },
        {  460800,       1,     1 },
        {   76800,      11,     1 },
        {  153600,       5,     1 },
        {  307200,       3,     1 },
        {  614400,       3,     0 },
        {  921600,       0,     1 },
};

int
sab_match(device_t parent, cfdata_t match, void *aux)
{
        struct ebus_attach_args *ea = aux;
        char *compat;

        if (strcmp(ea->ea_name, "se") == 0 ||
            strcmp(ea->ea_name, "FJSV,se") == 0)
                return (1);

        compat = prom_getpropstring(ea->ea_node, "compatible");
        if (compat != NULL && !strcmp(compat, "sab82532"))
                return (1);

        return (0);
}

void
sab_attach(device_t parent, device_t self, void *aux)
{
        struct sab_softc *sc = device_private(self);
        struct ebus_attach_args *ea = aux;
        uint8_t r;
        u_int i;
        int locs[SABCF_NLOCS];

        sc->sc_dev = self;
        sc->sc_bt = ea->ea_bustag;
        sc->sc_node = ea->ea_node;

        /* Use prom mapping, if available. */
        if (ea->ea_nvaddr)
                sparc_promaddr_to_handle(sc->sc_bt, ea->ea_vaddr[0],
                    &sc->sc_bh);
        else if (bus_space_map(sc->sc_bt, EBUS_ADDR_FROM_REG(&ea->ea_reg[0]),
                                 ea->ea_reg[0].size, 0, &sc->sc_bh) != 0) {
                printf(": can't map register space\n");
                return;
        }

        sc->sc_ih = bus_intr_establish(ea->ea_bustag, ea->ea_intr[0],
            IPL_TTY, sab_intr, sc);
        if (sc->sc_ih == NULL) {
                printf(": can't map interrupt\n");
                return;
        }

        sc->sc_softintr = softint_establish(SOFTINT_SERIAL, sab_softintr, sc);
        if (sc->sc_softintr == NULL) {
                printf(": can't get soft intr\n");
                return;
        }

        aprint_normal(": rev ");
        r = SAB_READ(sc, SAB_VSTR) & SAB_VSTR_VMASK;
        switch (r) {
        case SAB_VSTR_V_1:
                aprint_normal("1");
                break;
        case SAB_VSTR_V_2:
                aprint_normal("2");
                break;
        case SAB_VSTR_V_32:
                aprint_normal("3.2");
                break;
        default:
                aprint_normal("unknown(0x%x)", r);
                break;
        }
        aprint_normal("\n");
        aprint_naive(": Serial controller\n");

        /* Let current output drain */
        DELAY(100000);

        /* Set all pins, except DTR pins to be inputs */
        SAB_WRITE(sc, SAB_PCR, ~(SAB_PVR_DTR_A | SAB_PVR_DTR_B));
        /* Disable port interrupts */
        SAB_WRITE(sc, SAB_PIM, 0xff);
        SAB_WRITE(sc, SAB_PVR, SAB_PVR_DTR_A | SAB_PVR_DTR_B | SAB_PVR_MAGIC);
        SAB_WRITE(sc, SAB_IPC, SAB_IPC_ICPL);

        for (i = 0; i < SAB_NCHAN; i++) {
                struct sabtty_attach_args stax;

                stax.sbt_portno = i;

                locs[SABCF_CHANNEL] = i;

                sc->sc_child[i] = device_private(
                    config_found(self, &stax, sab_print,
                                 CFARGS(.submatch = config_stdsubmatch,
                                        .locators = locs)));
                if (sc->sc_child[i] != NULL)
                        sc->sc_nchild++;
        }
}

int
sab_print(void *args, const char *name)
{
        struct sabtty_attach_args *sa = args;

        if (name)
                aprint_normal("sabtty at %s", name);
        aprint_normal(" port %u", sa->sbt_portno);
        return (UNCONF);
}

int
sab_intr(void *vsc)
{
        struct sab_softc *sc = vsc;
        int r = 0, needsoft = 0;
        uint8_t gis;

        gis = SAB_READ(sc, SAB_GIS);

        /* channel A */
        if ((gis & (SAB_GIS_ISA1 | SAB_GIS_ISA0)) && sc->sc_child[0] &&
            sc->sc_child[0]->sc_tty)
                r |= sabtty_intr(sc->sc_child[0], &needsoft);

        /* channel B */
        if ((gis & (SAB_GIS_ISB1 | SAB_GIS_ISB0)) && sc->sc_child[1] &&
            sc->sc_child[1]->sc_tty)
                r |= sabtty_intr(sc->sc_child[1], &needsoft);

        if (needsoft)
                softint_schedule(sc->sc_softintr);

        return (r);
}

void
sab_softintr(void *vsc)
{
        struct sab_softc *sc = vsc;

        if (sc->sc_child[0] && sc->sc_child[0]->sc_tty)
                sabtty_softintr(sc->sc_child[0]);
        if (sc->sc_child[1] && sc->sc_child[1]->sc_tty)
                sabtty_softintr(sc->sc_child[1]);
}

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

        return (1);
}

void
sabtty_attach(device_t parent, device_t self, void *aux)
{
        struct sabtty_softc *sc = device_private(self);
        struct sabtty_attach_args *sa = aux;
        int r;
        int maj;
        int is_kgdb = 0;

        sc->sc_dev = self;
#ifdef KGDB
        is_kgdb = sab_kgdb_check(sc);
#endif

        if (!is_kgdb) {
                sc->sc_tty = tty_alloc();
                if (sc->sc_tty == NULL) {
                        aprint_normal(": failed to allocate tty\n");
                        return;
                }
                tty_attach(sc->sc_tty);
                sc->sc_tty->t_oproc = sabtty_start;
                sc->sc_tty->t_param = sabtty_param;
        }

        sc->sc_parent = device_private(parent);
        sc->sc_bt = sc->sc_parent->sc_bt;
        sc->sc_portno = sa->sbt_portno;
        sc->sc_rend = sc->sc_rbuf + SABTTY_RBUF_SIZE;

        switch (sa->sbt_portno) {
        case 0: /* port A */
                sc->sc_pvr_dtr = SAB_PVR_DTR_A;
                sc->sc_pvr_dsr = SAB_PVR_DSR_A;
                r = bus_space_subregion(sc->sc_bt, sc->sc_parent->sc_bh,
                    SAB_CHAN_A, SAB_CHANLEN, &sc->sc_bh);
                break;
        case 1: /* port B */
                sc->sc_pvr_dtr = SAB_PVR_DTR_B;
                sc->sc_pvr_dsr = SAB_PVR_DSR_B;
                r = bus_space_subregion(sc->sc_bt, sc->sc_parent->sc_bh,
                    SAB_CHAN_B, SAB_CHANLEN, &sc->sc_bh);
                break;
        default:
                aprint_normal(": invalid channel: %u\n", sa->sbt_portno);
                return;
        }
        if (r != 0) {
                aprint_normal(": failed to allocate register subregion\n");
                return;
        }

        sabtty_console_flags(sc);

        if (sc->sc_flags & (SABTTYF_CONS_IN | SABTTYF_CONS_OUT)) {
                struct termios t;
                const char *acc;

                /* Let residual prom output drain */
                DELAY(100000);

                switch (sc->sc_flags & (SABTTYF_CONS_IN | SABTTYF_CONS_OUT)) {
                case SABTTYF_CONS_IN:
                        acc = "input";
                        break;
                case SABTTYF_CONS_OUT:
                        acc = "output";
                        break;
                case SABTTYF_CONS_IN|SABTTYF_CONS_OUT:
                default:
                        acc = "i/o";
                        break;
                }

                t.c_ispeed= 0;
                if (sc->sc_flags & SABTTYF_IS_RSC)
                        t.c_ospeed = 115200;
                else
                        t.c_ospeed = 9600;
                t.c_cflag = CREAD | CS8 | HUPCL;
                sc->sc_tty->t_ospeed = 0;
                sabttyparam(sc, sc->sc_tty, &t);

                if (sc->sc_flags & SABTTYF_CONS_IN) {
                        sabtty_cons_input = sc;
                        cn_tab->cn_pollc = sab_cnpollc;
                        cn_tab->cn_getc = sab_cngetc;
                        maj = cdevsw_lookup_major(&sabtty_cdevsw);
                        cn_tab->cn_dev = makedev(maj, device_unit(self));
                        pmf_device_register1(self, NULL, NULL, sabtty_shutdown);
                        cn_init_magic(&sabtty_cnm_state);
                        cn_set_magic("\047\001"); /* default magic is BREAK */
                }

                if (sc->sc_flags & SABTTYF_CONS_OUT) {
                        sabtty_tec_wait(sc);
                        sabtty_cons_output = sc;
                        cn_tab->cn_putc = sab_cnputc;
                        maj = cdevsw_lookup_major(&sabtty_cdevsw);
                        cn_tab->cn_dev = makedev(maj, device_unit(self));
                }
                aprint_normal(": console %s", acc);
        } else {
                /* Not a console... */
                sabtty_reset(sc);

#ifdef KGDB
                if (is_kgdb) {
                        sab_kgdb_init(sc);
                        aprint_normal(": kgdb");
                }
#endif
        }

        aprint_normal("\n");
        aprint_naive(": Serial port\n");
}

int
sabtty_intr(struct sabtty_softc *sc, int *needsoftp)
{
        uint8_t isr0, isr1;
        int i, len = 0, needsoft = 0, r = 0, clearfifo = 0;

        isr0 = SAB_READ(sc, SAB_ISR0);
        isr1 = SAB_READ(sc, SAB_ISR1);

        if (isr0 || isr1)
                r = 1;

        if (isr0 & SAB_ISR0_RPF) {
                len = 32;
                clearfifo = 1;
        }
        if (isr0 & SAB_ISR0_TCD) {
                len = (32 - 1) & SAB_READ(sc, SAB_RBCL);
                clearfifo = 1;
        }
        if (isr0 & SAB_ISR0_TIME) {
                sabtty_cec_wait(sc);
                SAB_WRITE(sc, SAB_CMDR, SAB_CMDR_RFRD);
        }
        if (isr0 & SAB_ISR0_RFO) {
                sc->sc_flags |= SABTTYF_RINGOVERFLOW;
                clearfifo = 1;
        }
        if (len != 0) {
                uint8_t *ptr, b;

                ptr = sc->sc_rput;
                for (i = 0; i < len; i++) {
                        b = SAB_READ(sc, SAB_RFIFO);
                        if (i % 2 == 0) /* skip status byte */
                                cn_check_magic(sc->sc_tty->t_dev,
                                               b, sabtty_cnm_state);
                        *ptr++ = b;
                        if (ptr == sc->sc_rend)
                                ptr = sc->sc_rbuf;
                        if (ptr == sc->sc_rget) {
                                if (ptr == sc->sc_rbuf)
                                        ptr = sc->sc_rend;
                                ptr--;
                                sc->sc_flags |= SABTTYF_RINGOVERFLOW;
                        }
                }
                sc->sc_rput = ptr;
                needsoft = 1;
        }

        if (clearfifo) {
                sabtty_cec_wait(sc);
                SAB_WRITE(sc, SAB_CMDR, SAB_CMDR_RMC);
        }

        if (isr0 & SAB_ISR0_CDSC) {
                sc->sc_flags |= SABTTYF_CDCHG;
                needsoft = 1;
        }

        if (isr1 & SAB_ISR1_BRKT)
                cn_check_magic(sc->sc_tty->t_dev,
                               CNC_BREAK, sabtty_cnm_state);

        if (isr1 & (SAB_ISR1_XPR | SAB_ISR1_ALLS)) {
                if ((SAB_READ(sc, SAB_STAR) & SAB_STAR_XFW) &&
                    (sc->sc_flags & SABTTYF_STOP) == 0) {
                        if (sc->sc_txc < 32)
                                len = sc->sc_txc;
                        else
                                len = 32;

                        if (len > 0) {
                                SAB_WRITE_BLOCK(sc, SAB_XFIFO, sc->sc_txp, len);
                                sc->sc_txp += len;
                                sc->sc_txc -= len;

                                sabtty_cec_wait(sc);
                                SAB_WRITE(sc, SAB_CMDR, SAB_CMDR_XF);

                                /*
                                 * Prevent the false end of xmit from
                                 * confusing things below.
                                 */
                                isr1 &= ~SAB_ISR1_ALLS;
                        }
                }

                if ((sc->sc_txc == 0) || (sc->sc_flags & SABTTYF_STOP)) {
                        if ((sc->sc_imr1 & SAB_IMR1_XPR) == 0) {
                                sc->sc_imr1 |= SAB_IMR1_XPR;
                                sc->sc_imr1 &= ~SAB_IMR1_ALLS;
                                SAB_WRITE(sc, SAB_IMR1, sc->sc_imr1);
                        }
                }
        }

        if ((isr1 & SAB_ISR1_ALLS) && ((sc->sc_txc == 0) ||
            (sc->sc_flags & SABTTYF_STOP))) {
                if (sc->sc_flags & SABTTYF_TXDRAIN)
                        wakeup(sc);
                sc->sc_flags &= ~SABTTYF_STOP;
                sc->sc_flags |= SABTTYF_DONE;
                sc->sc_imr1 |= SAB_IMR1_ALLS;
                SAB_WRITE(sc, SAB_IMR1, sc->sc_imr1);
                needsoft = 1;
        }

        if (needsoft)
                *needsoftp = needsoft;
        return (r);
}

void
sabtty_softintr(struct sabtty_softc *sc)
{
        struct tty *tp = sc->sc_tty;
        int s, flags;
        uint8_t r;

        if (tp == NULL)
                return;

        if ((tp->t_state & TS_ISOPEN) == 0)
                return;

        while (sc->sc_rget != sc->sc_rput) {
                int data;
                uint8_t stat;

                data = sc->sc_rget[0];
                stat = sc->sc_rget[1];
                sc->sc_rget += 2;
                if (stat & SAB_RSTAT_PE)
                        data |= TTY_PE;
                if (stat & SAB_RSTAT_FE)
                        data |= TTY_FE;
                if (sc->sc_rget == sc->sc_rend)
                        sc->sc_rget = sc->sc_rbuf;

                (*tp->t_linesw->l_rint)(data, tp);
        }

        s = splhigh();
        flags = sc->sc_flags;
        sc->sc_flags &= ~(SABTTYF_DONE|SABTTYF_CDCHG|SABTTYF_RINGOVERFLOW);
        splx(s);

        if (flags & SABTTYF_CDCHG) {
                s = spltty();
                r = SAB_READ(sc, SAB_VSTR) & SAB_VSTR_CD;
                splx(s);

                (*tp->t_linesw->l_modem)(tp, r);
        }

        if (flags & SABTTYF_RINGOVERFLOW)
                log(LOG_WARNING, "%s: ring overflow\n",
                    device_xname(sc->sc_dev));

        if (flags & SABTTYF_DONE) {
                ndflush(&tp->t_outq, sc->sc_txp - tp->t_outq.c_cf);
                tp->t_state &= ~TS_BUSY;
                (*tp->t_linesw->l_start)(tp);
        }
}

int
sabopen(dev_t dev, int flags, int mode, struct lwp *l)
{
        struct sabtty_softc *sc;
        struct tty *tp;
        int s, s1;

        sc = device_lookup_private(&sabtty_cd, SABUNIT(dev));
        if (sc == NULL)
                return (ENXIO);

        tp = sc->sc_tty;
        tp->t_dev = dev;

        /*
         * If the device is exclusively for kernel use, deny userland
         * open.
         */
        if (ISSET(tp->t_state, TS_KERN_ONLY))
                return (EBUSY);

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

        ttylock(tp);
        if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
                ttychars(tp);
                tp->t_iflag = TTYDEF_IFLAG;
                tp->t_oflag = TTYDEF_OFLAG;
                tp->t_cflag = TTYDEF_CFLAG;
                if (sc->sc_openflags & TIOCFLAG_CLOCAL)
                        tp->t_cflag |= CLOCAL;
                if (sc->sc_openflags & TIOCFLAG_CRTSCTS)
                        tp->t_cflag |= CRTSCTS;
                if (sc->sc_openflags & TIOCFLAG_MDMBUF)
                        tp->t_cflag |= MDMBUF;
                tp->t_lflag = TTYDEF_LFLAG;
                tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;

                sc->sc_rput = sc->sc_rget = sc->sc_rbuf;

                ttsetwater(tp);

                s1 = splhigh();
                sabtty_reset(sc);
                sabtty_param(tp, &tp->t_termios);
                sc->sc_imr0 = SAB_IMR0_PERR | SAB_IMR0_FERR | SAB_IMR0_PLLA;
                SAB_WRITE(sc, SAB_IMR0, sc->sc_imr0);
                sc->sc_imr1 = SAB_IMR1_BRK | SAB_IMR1_ALLS | SAB_IMR1_XDU |
                    SAB_IMR1_TIN | SAB_IMR1_CSC | SAB_IMR1_XMR | SAB_IMR1_XPR;
                SAB_WRITE(sc, SAB_IMR1, sc->sc_imr1);
                SAB_WRITE(sc, SAB_CCR0, SAB_READ(sc, SAB_CCR0) | SAB_CCR0_PU);
                sabtty_cec_wait(sc);
                SAB_WRITE(sc, SAB_CMDR, SAB_CMDR_XRES);
                sabtty_cec_wait(sc);
                SAB_WRITE(sc, SAB_CMDR, SAB_CMDR_RRES);
                sabtty_cec_wait(sc);
                splx(s1);

                sabtty_flush(sc);

                if ((sc->sc_openflags & TIOCFLAG_SOFTCAR) ||
                    (SAB_READ(sc, SAB_VSTR) & SAB_VSTR_CD))
                        tp->t_state |= TS_CARR_ON;
                else
                        tp->t_state &= ~TS_CARR_ON;
        }

        if ((flags & O_NONBLOCK) == 0) {
                while ((tp->t_cflag & CLOCAL) == 0 &&
                    (tp->t_state & TS_CARR_ON) == 0) {
                        int error;

                        error = ttysleep(tp, &tp->t_rawcv, true, 0);
                        if (error != 0) {
                                ttyunlock(tp);
                                return (error);
                        }
                }
        }

        ttyunlock(tp);

        s = (*tp->t_linesw->l_open)(dev, tp);
        if (s != 0) {
                ttylock(tp);
                if (tp->t_state & TS_ISOPEN) {
                        ttyunlock(tp);
                        return (s);
                }
                if (tp->t_cflag & HUPCL) {
                        sabtty_mdmctrl(sc, 0, DMSET);
                        ttysleep(tp, NULL, /*catch_p*/false, hz);
                }

                if ((sc->sc_flags & (SABTTYF_CONS_IN | SABTTYF_CONS_OUT)) == 0) {
                        /* Flush and power down if we're not the console */
                        sabtty_flush(sc);
                        sabtty_reset(sc);
                }
                ttyunlock(tp);
        }
        return (s);
}

int
sabclose(dev_t dev, int flags, int mode, struct lwp *l)
{
        struct sabtty_softc *sc = device_lookup_private(&sabtty_cd, SABUNIT(dev));
        struct sab_softc *bc = sc->sc_parent;
        struct tty *tp = sc->sc_tty;
        int s;

        (*tp->t_linesw->l_close)(tp, flags);

        s = spltty();

        if ((tp->t_state & TS_ISOPEN) == 0) {
                /* Wait for output drain */
                sc->sc_imr1 &= ~SAB_IMR1_ALLS;
                SAB_WRITE(sc, SAB_IMR1, sc->sc_imr1);
                sc->sc_flags |= SABTTYF_TXDRAIN;
                (void)tsleep(sc, TTIPRI, ttclos, 5 * hz);
                sc->sc_imr1 |= SAB_IMR1_ALLS;
                SAB_WRITE(sc, SAB_IMR1, sc->sc_imr1);
                sc->sc_flags &= ~SABTTYF_TXDRAIN;

                if (tp->t_cflag & HUPCL) {
                        sabtty_mdmctrl(sc, 0, DMSET);
                        (void)tsleep(bc, TTIPRI, ttclos, hz);
                }

                if ((sc->sc_flags & (SABTTYF_CONS_IN | SABTTYF_CONS_OUT)) == 0) {
                        /* Flush and power down if we're not the console */
                        sabtty_flush(sc);
                        sabtty_reset(sc);
                }
        }

        ttyclose(tp);
        splx(s);

        return (0);
}

int
sabread(dev_t dev, struct uio *uio, int flags)
{
        struct sabtty_softc *sc = device_lookup_private(&sabtty_cd, SABUNIT(dev));
        struct tty *tp = sc->sc_tty;

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

int
sabwrite(dev_t dev, struct uio *uio, int flags)
{
        struct sabtty_softc *sc = device_lookup_private(&sabtty_cd, SABUNIT(dev));
        struct tty *tp = sc->sc_tty;

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

int
sabioctl(dev_t dev, u_long cmd, void *data, int flags, struct lwp *l)
{
        struct sabtty_softc *sc = device_lookup_private(&sabtty_cd, SABUNIT(dev));
        struct tty *tp = sc->sc_tty;
        int error;

        error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flags, l);
        if (error >= 0)
                return (error);

        error = ttioctl(tp, cmd, data, flags, l);
        if (error >= 0)
                return (error);

        error = 0;

        switch (cmd) {
        case TIOCSBRK:
                SAB_WRITE(sc, SAB_DAFO,
                    SAB_READ(sc, SAB_DAFO) | SAB_DAFO_XBRK);
                break;
        case TIOCCBRK:
                SAB_WRITE(sc, SAB_DAFO,
                    SAB_READ(sc, SAB_DAFO) & ~SAB_DAFO_XBRK);
                break;
        case TIOCSDTR:
                sabtty_mdmctrl(sc, TIOCM_DTR, DMBIS);
                break;
        case TIOCCDTR:
                sabtty_mdmctrl(sc, TIOCM_DTR, DMBIC);
                break;
        case TIOCMBIS:
                sabtty_mdmctrl(sc, *((int *)data), DMBIS);
                break;
        case TIOCMBIC:
                sabtty_mdmctrl(sc, *((int *)data), DMBIC);
                break;
        case TIOCMGET:
                *((int *)data) = sabtty_mdmctrl(sc, 0, DMGET);
                break;
        case TIOCMSET:
                sabtty_mdmctrl(sc, *((int *)data), DMSET);
                break;
        case TIOCGFLAGS:
                *((int *)data) = sc->sc_openflags;
                break;
        case TIOCSFLAGS:
                if (kauth_authorize_device_tty(l->l_cred,
                    KAUTH_DEVICE_TTY_PRIVSET, tp))
                        error = EPERM;
                else
                        sc->sc_openflags = *((int *)data) &
                            (TIOCFLAG_SOFTCAR | TIOCFLAG_CLOCAL |
                             TIOCFLAG_CRTSCTS | TIOCFLAG_MDMBUF);
                break;
        default:
                error = ENOTTY;
        }

        return (error);
}

struct tty *
sabtty(dev_t dev)
{
        struct sabtty_softc *sc = device_lookup_private(&sabtty_cd, SABUNIT(dev));

        return (sc->sc_tty);
}

void
sabstop(struct tty *tp, int flag)
{
        struct sabtty_softc *sc = device_lookup_private(&sabtty_cd, SABUNIT(tp->t_dev));
        int s;

        s = spltty();
        if (tp->t_state & TS_BUSY) {
                if ((tp->t_state & TS_TTSTOP) == 0)
                        tp->t_state |= TS_FLUSH;
                sc->sc_flags |= SABTTYF_STOP;
                sc->sc_imr1 &= ~SAB_IMR1_ALLS;
                SAB_WRITE(sc, SAB_IMR1, sc->sc_imr1);
        }
        splx(s);
}

int
sabpoll(dev_t dev, int events, struct lwp *l)
{
        struct sabtty_softc *sc = device_lookup_private(&sabtty_cd, SABUNIT(dev));
        struct tty *tp = sc->sc_tty;

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

int
sabtty_mdmctrl(struct sabtty_softc *sc, int bits, int how)
{
        uint8_t r;
        int s;

        s = spltty();
        switch (how) {
        case DMGET:
                bits = 0;
                if (SAB_READ(sc, SAB_STAR) & SAB_STAR_CTS)
                        bits |= TIOCM_CTS;
                if ((SAB_READ(sc, SAB_VSTR) & SAB_VSTR_CD) == 0)
                        bits |= TIOCM_CD;

                r = SAB_READ(sc, SAB_PVR);
                if ((r & sc->sc_pvr_dtr) == 0)
                        bits |= TIOCM_DTR;
                if ((r & sc->sc_pvr_dsr) == 0)
                        bits |= TIOCM_DSR;

                r = SAB_READ(sc, SAB_MODE);
                if ((r & (SAB_MODE_RTS|SAB_MODE_FRTS)) == SAB_MODE_RTS)
                        bits |= TIOCM_RTS;
                break;
        case DMSET:
                r = SAB_READ(sc, SAB_MODE);
                if (bits & TIOCM_RTS) {
                        r &= ~SAB_MODE_FRTS;
                        r |= SAB_MODE_RTS;
                } else
                        r |= SAB_MODE_FRTS | SAB_MODE_RTS;
                SAB_WRITE(sc, SAB_MODE, r);

                r = SAB_READ(sc, SAB_PVR);
                if (bits & TIOCM_DTR)
                        r &= ~sc->sc_pvr_dtr;
                else
                        r |= sc->sc_pvr_dtr;
                SAB_WRITE(sc, SAB_PVR, r);
                break;
        case DMBIS:
                if (bits & TIOCM_RTS) {
                        r = SAB_READ(sc, SAB_MODE);
                        r &= ~SAB_MODE_FRTS;
                        r |= SAB_MODE_RTS;
                        SAB_WRITE(sc, SAB_MODE, r);
                }
                if (bits & TIOCM_DTR) {
                        r = SAB_READ(sc, SAB_PVR);
                        r &= ~sc->sc_pvr_dtr;
                        SAB_WRITE(sc, SAB_PVR, r);
                }
                break;
        case DMBIC:
                if (bits & TIOCM_RTS) {
                        r = SAB_READ(sc, SAB_MODE);
                        r |= SAB_MODE_FRTS | SAB_MODE_RTS;
                        SAB_WRITE(sc, SAB_MODE, r);
                }
                if (bits & TIOCM_DTR) {
                        r = SAB_READ(sc, SAB_PVR);
                        r |= sc->sc_pvr_dtr;
                        SAB_WRITE(sc, SAB_PVR, r);
                }
                break;
        }
        splx(s);
        return (bits);
}

int
sabttyparam(struct sabtty_softc *sc, struct tty *tp, struct termios *t)
{
        int s, ospeed;
        tcflag_t cflag;
        uint8_t dafo, r;

        ospeed = sabtty_speed(t->c_ospeed);
        if (ospeed < 0 || (t->c_ispeed && t->c_ispeed != t->c_ospeed))
                return (EINVAL);

        s = spltty();

        /* hang up line if ospeed is zero, otherwise raise dtr */
        sabtty_mdmctrl(sc, TIOCM_DTR,
            (t->c_ospeed == 0) ? DMBIC : DMBIS);

        dafo = SAB_READ(sc, SAB_DAFO);

        cflag = t->c_cflag;

        if (sc->sc_flags & (SABTTYF_CONS_IN | SABTTYF_CONS_OUT)) {
                cflag |= CLOCAL;
                cflag &= ~HUPCL;
        }

        if (cflag & CSTOPB)
                dafo |= SAB_DAFO_STOP;
        else
                dafo &= ~SAB_DAFO_STOP;

        dafo &= ~SAB_DAFO_CHL_CSIZE;
        switch (cflag & CSIZE) {
        case CS5:
                dafo |= SAB_DAFO_CHL_CS5;
                break;
        case CS6:
                dafo |= SAB_DAFO_CHL_CS6;
                break;
        case CS7:
                dafo |= SAB_DAFO_CHL_CS7;
                break;
        default:
                dafo |= SAB_DAFO_CHL_CS8;
                break;
        }

        dafo &= ~SAB_DAFO_PARMASK;
        if (cflag & PARENB) {
                if (cflag & PARODD)
                        dafo |= SAB_DAFO_PAR_ODD;
                else
                        dafo |= SAB_DAFO_PAR_EVEN;
        } else
                dafo |= SAB_DAFO_PAR_NONE;
        SAB_WRITE(sc, SAB_DAFO, dafo);

        if (!(sc->sc_flags & SABTTYF_IS_RSC) && ospeed != 0) {
                SAB_WRITE(sc, SAB_BGR, ospeed & 0xff);
                r = SAB_READ(sc, SAB_CCR2);
                r &= ~(SAB_CCR2_BR9 | SAB_CCR2_BR8);
                r |= (ospeed >> 2) & (SAB_CCR2_BR9 | SAB_CCR2_BR8);
                SAB_WRITE(sc, SAB_CCR2, r);
        }

        r = SAB_READ(sc, SAB_MODE);
        r |= SAB_MODE_RAC;
        if (cflag & CRTSCTS) {
                r &= ~(SAB_MODE_RTS | SAB_MODE_FCTS);
                r |= SAB_MODE_FRTS;
                sc->sc_imr1 &= ~SAB_IMR1_CSC;
        } else {
                r |= SAB_MODE_RTS | SAB_MODE_FCTS;
                r &= ~SAB_MODE_FRTS;
                sc->sc_imr1 |= SAB_IMR1_CSC;
        }
        SAB_WRITE(sc, SAB_MODE, r);
        SAB_WRITE(sc, SAB_IMR1, sc->sc_imr1);

        tp->t_cflag = cflag;

        splx(s);
        return (0);
}

int
sabtty_param(struct tty *tp, struct termios *t)
{
        struct sabtty_softc *sc = device_lookup_private(&sabtty_cd, SABUNIT(tp->t_dev));

        return (sabttyparam(sc, tp, t));
}

void
sabtty_start(struct tty *tp)
{
        struct sabtty_softc *sc = device_lookup_private(&sabtty_cd, SABUNIT(tp->t_dev));
        int s;

        s = spltty();
        if ((tp->t_state & (TS_TTSTOP | TS_TIMEOUT | TS_BUSY)) == 0) {
                if (ttypull(tp)) {
                        sc->sc_txc = ndqb(&tp->t_outq, 0);
                        sc->sc_txp = tp->t_outq.c_cf;
                        tp->t_state |= TS_BUSY;
                        sc->sc_imr1 &= ~(SAB_ISR1_XPR | SAB_ISR1_ALLS);
                        SAB_WRITE(sc, SAB_IMR1, sc->sc_imr1);
                }
        }
        splx(s);
}

void
sabtty_cec_wait(struct sabtty_softc *sc)
{
        int i = 50000;

        for (;;) {
                if ((SAB_READ(sc, SAB_STAR) & SAB_STAR_CEC) == 0)
                        return;
                if (--i == 0)
                        break;
                DELAY(1);
        }
}

void
sabtty_tec_wait(struct sabtty_softc *sc)
{
        int i = 200000;

        for (;;) {
                if ((SAB_READ(sc, SAB_STAR) & SAB_STAR_TEC) == 0)
                        return;
                if (--i == 0)
                        break;
                DELAY(1);
        }
}

void
sabtty_reset(struct sabtty_softc *sc)
{
        /* power down */
        SAB_WRITE(sc, SAB_CCR0, 0);

        /* set basic configuration */
        SAB_WRITE(sc, SAB_CCR0,
            SAB_CCR0_MCE | SAB_CCR0_SC_NRZ | SAB_CCR0_SM_ASYNC);
        SAB_WRITE(sc, SAB_CCR1, SAB_CCR1_ODS | SAB_CCR1_BCR | SAB_CCR1_CM_7);
        SAB_WRITE(sc, SAB_CCR2, SAB_CCR2_BDF | SAB_CCR2_SSEL | SAB_CCR2_TOE);
        SAB_WRITE(sc, SAB_CCR3, 0);
        SAB_WRITE(sc, SAB_CCR4, SAB_CCR4_MCK4 | SAB_CCR4_EBRG | SAB_CCR4_ICD);
        SAB_WRITE(sc, SAB_MODE, SAB_MODE_RTS | SAB_MODE_FCTS | SAB_MODE_RAC);
        SAB_WRITE(sc, SAB_RFC,
            SAB_RFC_DPS | SAB_RFC_RFDF | SAB_RFC_RFTH_32CHAR);

        /* clear interrupts */
        sc->sc_imr0 = sc->sc_imr1 = 0xff;
        SAB_WRITE(sc, SAB_IMR0, sc->sc_imr0);
        SAB_WRITE(sc, SAB_IMR1, sc->sc_imr1);
        (void)SAB_READ(sc, SAB_ISR0);
        (void)SAB_READ(sc, SAB_ISR1);
}

void
sabtty_flush(struct sabtty_softc *sc)
{
        /* clear rx fifo */
        sabtty_cec_wait(sc);
        SAB_WRITE(sc, SAB_CMDR, SAB_CMDR_RRES);

        /* clear tx fifo */
        sabtty_cec_wait(sc);
        SAB_WRITE(sc, SAB_CMDR, SAB_CMDR_XRES);
}

int
sabtty_speed(int rate)
{
        int i, len, r;

        if (rate == 0)
                return (0);
        len = sizeof(sabtty_baudtable)/sizeof(sabtty_baudtable[0]);
        for (i = 0; i < len; i++) {
                if (rate == sabtty_baudtable[i].baud) {
                        r = sabtty_baudtable[i].n |
                            (sabtty_baudtable[i].m << 6);
                        return (r);
                }
        }
        return (-1);
}

void
sabtty_cnputc(struct sabtty_softc *sc, int c)
{
        sabtty_tec_wait(sc);
        SAB_WRITE(sc, SAB_TIC, c);
        sabtty_tec_wait(sc);
}

int
sabtty_cngetc(struct sabtty_softc *sc)
{
        uint8_t r, len;

again:
        do {
                r = SAB_READ(sc, SAB_STAR);
        } while ((r & SAB_STAR_RFNE) == 0);

        /*
         * Ok, at least one byte in RFIFO, ask for permission to access RFIFO
         * (I hate this chip... hate hate hate).
         */
        sabtty_cec_wait(sc);
        SAB_WRITE(sc, SAB_CMDR, SAB_CMDR_RFRD);

        /* Wait for RFIFO to come ready */
        do {
                r = SAB_READ(sc, SAB_ISR0);
        } while ((r & SAB_ISR0_TCD) == 0);

        len = SAB_READ(sc, SAB_RBCL) & (32 - 1);
        if (len == 0)
                goto again;     /* Shouldn't happen... */

        r = SAB_READ(sc, SAB_RFIFO);

        /*
         * Blow away everything left in the FIFO...
         */
        sabtty_cec_wait(sc);
        SAB_WRITE(sc, SAB_CMDR, SAB_CMDR_RMC);
        return (r);
}

void
sabtty_cnpollc(struct sabtty_softc *sc, int on)
{
        uint8_t r;

        if (on) {
                if (sc->sc_polling)
                        return;
                SAB_WRITE(sc, SAB_IPC, SAB_READ(sc, SAB_IPC) | SAB_IPC_VIS);
                r = sc->sc_pollrfc = SAB_READ(sc, SAB_RFC);
                r &= ~(SAB_RFC_RFDF);
                SAB_WRITE(sc, SAB_RFC, r);
                sabtty_cec_wait(sc);
                SAB_WRITE(sc, SAB_CMDR, SAB_CMDR_RRES);
                sc->sc_polling = 1;
        } else {
                if (!sc->sc_polling)
                        return;
                SAB_WRITE(sc, SAB_IPC, SAB_READ(sc, SAB_IPC) & ~SAB_IPC_VIS);
                SAB_WRITE(sc, SAB_RFC, sc->sc_pollrfc);
                sabtty_cec_wait(sc);
                SAB_WRITE(sc, SAB_CMDR, SAB_CMDR_RRES);
                sc->sc_polling = 0;
        }
}

void
sab_cnputc(dev_t dev, int c)
{
        struct sabtty_softc *sc = sabtty_cons_output;

        if (sc == NULL)
                return;
        sabtty_cnputc(sc, c);
}

void
sab_cnpollc(dev_t dev, int on)
{
        struct sabtty_softc *sc = sabtty_cons_input;

        sabtty_cnpollc(sc, on);
}

int
sab_cngetc(dev_t dev)
{
        struct sabtty_softc *sc = sabtty_cons_input;

        if (sc == NULL)
                return (-1);
        return (sabtty_cngetc(sc));
}

void
sabtty_console_flags(struct sabtty_softc *sc)
{
        int node, channel, cookie;
        char buf[255];

        node = sc->sc_parent->sc_node;
        channel = sc->sc_portno;

        /* Default to channel 0 if there are no explicit prom args */
        cookie = 0;

        if (node == prom_instance_to_package(prom_stdin())) {
                if (prom_getoption("input-device", buf, sizeof buf) == 0 &&
                        strcmp("ttyb", buf) == 0)
                                cookie = 1;

                if (channel == cookie)
                        sc->sc_flags |= SABTTYF_CONS_IN;
        }

        /* Default to same channel if there are no explicit prom args */

        if (node == prom_instance_to_package(prom_stdout())) {
                if (prom_getoption("output-device", buf, sizeof buf) == 0 &&
                        strcmp("ttyb", buf) == 0)
                                cookie = 1;

                if (channel == cookie)
                        sc->sc_flags |= SABTTYF_CONS_OUT;
        }
        /* Are we connected to an E250 RSC? */
        if (channel == prom_getpropint(node, "ssp-console", -1) ||
            channel == prom_getpropint(node, "ssp-control", -1))
                sc->sc_flags |= SABTTYF_IS_RSC;
}

bool
sabtty_shutdown(device_t dev, int how)
{
        struct sabtty_softc *sc = device_private(dev);

        /* Have to put the chip back into single char mode */
        sc->sc_flags |= SABTTYF_DONTDDB;
        SAB_WRITE(sc, SAB_RFC, SAB_READ(sc, SAB_RFC) & ~SAB_RFC_RFDF);
        sabtty_cec_wait(sc);
        SAB_WRITE(sc, SAB_CMDR, SAB_CMDR_RRES);
        sabtty_cec_wait(sc);
        return true;
}

#ifdef KGDB
static int
sab_kgdb_getc(void *arg)
{
        struct sabtty_softc *sc = arg;

        return sabtty_cngetc(sc);
}

static void
sab_kgdb_putc(void *arg, int c)
{
        struct sabtty_softc *sc = arg;

        return sabtty_cnputc(sc, c);
}

#ifndef KGDB_DEVRATE
#define KGDB_DEVRATE    9600
#endif

int
sab_kgdb_check(struct sabtty_softc *sc)
{
        return strcmp(device_xname(sc->sc_dev), KGDB_DEVNAME) == 0;
}

void
sab_kgdb_init(struct sabtty_softc *sc)
{
        int sp;
        uint8_t dafo, r;
        extern int kgdb_break_at_attach;

        kgdb_attach(sab_kgdb_getc, sab_kgdb_putc, sc);
        kgdb_dev = 123; /* not used, but checked against NODEV */

        /*
         * Configure the port to speed/8n1
         */
        dafo = SAB_READ(sc, SAB_DAFO);
        dafo &= ~(SAB_DAFO_STOP|SAB_DAFO_CHL_CSIZE|SAB_DAFO_PARMASK);
        dafo |= SAB_DAFO_CHL_CS8|SAB_DAFO_PAR_NONE;
        SAB_WRITE(sc, SAB_DAFO, dafo);
        sp = sabtty_speed(KGDB_DEVRATE);
        SAB_WRITE(sc, SAB_BGR, sp & 0xff);
        r = SAB_READ(sc, SAB_CCR2);
        r &= ~(SAB_CCR2_BR9 | SAB_CCR2_BR8);
        r |= (sp >> 2) & (SAB_CCR2_BR9 | SAB_CCR2_BR8);
        SAB_WRITE(sc, SAB_CCR2, r);

        /*
         * If we are booting with -d, break into kgdb now
         */
        if (kgdb_break_at_attach)
                kgdb_connect(1);
}
#endif