/*      $NetBSD: ucom.c,v 1.40 2001/11/13 06:24:54 lukem Exp $  */

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2001-2003, 2005, 2008
 *      Shunsuke Akiyama <akiyama@jp.FreeBSD.org>.
 * 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 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 AUTHOR 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) 1998, 2000 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Lennart Augustsson (lennart@augustsson.net) at
 * Carlstedt Research & Technology.
 *
 * 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.
 */

#include <sys/stdint.h>
#include <sys/stddef.h>
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/types.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/condvar.h>
#include <sys/sysctl.h>
#include <sys/sx.h>
#include <sys/unistd.h>
#include <sys/callout.h>
#include <sys/malloc.h>
#include <sys/priv.h>
#include <sys/cons.h>

#include <dev/uart/uart_ppstypes.h>

#include <dev/usb/usb.h>
#include <dev/usb/usbdi.h>
#include <dev/usb/usbdi_util.h>

#define USB_DEBUG_VAR ucom_debug
#include <dev/usb/usb_debug.h>
#include <dev/usb/usb_busdma.h>
#include <dev/usb/usb_process.h>

#include <dev/usb/serial/usb_serial.h>

#include "opt_gdb.h"

static SYSCTL_NODE(_hw_usb, OID_AUTO, ucom, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "USB ucom");

static int ucom_pps_mode;

SYSCTL_INT(_hw_usb_ucom, OID_AUTO, pps_mode, CTLFLAG_RWTUN,
    &ucom_pps_mode, 0, 
    "pulse capture mode: 0/1/2=disabled/CTS/DCD; add 0x10 to invert");

static int ucom_device_mode_console = 1;

SYSCTL_INT(_hw_usb_ucom, OID_AUTO, device_mode_console, CTLFLAG_RW,
    &ucom_device_mode_console, 0,
    "set to 1 to mark terminals as consoles when in device mode");

#ifdef USB_DEBUG
static int ucom_debug = 0;

SYSCTL_INT(_hw_usb_ucom, OID_AUTO, debug, CTLFLAG_RWTUN,
    &ucom_debug, 0, "ucom debug level");
#endif

#define UCOM_CONS_BUFSIZE 1024

static uint8_t ucom_cons_rx_buf[UCOM_CONS_BUFSIZE];
static uint8_t ucom_cons_tx_buf[UCOM_CONS_BUFSIZE];

static unsigned ucom_cons_rx_low = 0;
static unsigned ucom_cons_rx_high = 0;

static unsigned ucom_cons_tx_low = 0;
static unsigned ucom_cons_tx_high = 0;

static int ucom_cons_unit = -1;
static int ucom_cons_subunit = 0;
static int ucom_cons_baud = 115200;
static struct ucom_softc *ucom_cons_softc = NULL;

SYSCTL_INT(_hw_usb_ucom, OID_AUTO, cons_unit, CTLFLAG_RWTUN,
    &ucom_cons_unit, 0, "console unit number");
SYSCTL_INT(_hw_usb_ucom, OID_AUTO, cons_subunit, CTLFLAG_RWTUN,
    &ucom_cons_subunit, 0, "console subunit number");
SYSCTL_INT(_hw_usb_ucom, OID_AUTO, cons_baud, CTLFLAG_RWTUN,
    &ucom_cons_baud, 0, "console baud rate");

static usb_proc_callback_t ucom_cfg_start_transfers;
static usb_proc_callback_t ucom_cfg_open;
static usb_proc_callback_t ucom_cfg_close;
static usb_proc_callback_t ucom_cfg_line_state;
static usb_proc_callback_t ucom_cfg_status_change;
static usb_proc_callback_t ucom_cfg_param;

static int      ucom_unit_alloc(void);
static void     ucom_unit_free(int);
static int      ucom_attach_tty(struct ucom_super_softc *, struct ucom_softc *);
static void     ucom_detach_tty(struct ucom_super_softc *, struct ucom_softc *);
static int      ucom_queue_command(struct ucom_softc *,
                    usb_proc_callback_t *, struct termios *pt,
                    struct usb_proc_msg *t0, struct usb_proc_msg *t1, bool wait);
static void     ucom_shutdown(struct ucom_softc *);
static void     ucom_ring(struct ucom_softc *, uint8_t);
static void     ucom_break(struct ucom_softc *, uint8_t);
static void     ucom_dtr(struct ucom_softc *, uint8_t);
static void     ucom_rts(struct ucom_softc *, uint8_t);

static tsw_open_t ucom_open;
static tsw_close_t ucom_close;
static tsw_ioctl_t ucom_ioctl;
static tsw_modem_t ucom_modem;
static tsw_param_t ucom_param;
static tsw_outwakeup_t ucom_outwakeup;
static tsw_inwakeup_t ucom_inwakeup;
static tsw_free_t ucom_free;
static tsw_busy_t ucom_busy;

static struct ttydevsw ucom_class = {
        .tsw_flags = TF_INITLOCK | TF_CALLOUT,
        .tsw_open = ucom_open,
        .tsw_close = ucom_close,
        .tsw_outwakeup = ucom_outwakeup,
        .tsw_inwakeup = ucom_inwakeup,
        .tsw_ioctl = ucom_ioctl,
        .tsw_param = ucom_param,
        .tsw_modem = ucom_modem,
        .tsw_free = ucom_free,
        .tsw_busy = ucom_busy,
};

MODULE_DEPEND(ucom, usb, 1, 1, 1);
MODULE_VERSION(ucom, 1);

#define UCOM_UNIT_MAX           128     /* maximum number of units */
#define UCOM_TTY_PREFIX         "U"

static struct unrhdr *ucom_unrhdr;
static struct mtx ucom_mtx;
static int ucom_close_refs;

static void
ucom_init(void *arg)
{
        DPRINTF("\n");
        ucom_unrhdr = new_unrhdr(0, UCOM_UNIT_MAX - 1, NULL);
        mtx_init(&ucom_mtx, "UCOM MTX", NULL, MTX_DEF);
}
SYSINIT(ucom_init, SI_SUB_KLD - 1, SI_ORDER_ANY, ucom_init, NULL);

static void
ucom_uninit(void *arg)
{
        struct unrhdr *hdr;
        hdr = ucom_unrhdr;
        ucom_unrhdr = NULL;

        DPRINTF("\n");

        if (hdr != NULL)
                delete_unrhdr(hdr);

        mtx_destroy(&ucom_mtx);
}
SYSUNINIT(ucom_uninit, SI_SUB_KLD - 3, SI_ORDER_ANY, ucom_uninit, NULL);

/*
 * Mark a unit number (the X in cuaUX) as in use.
 *
 * Note that devices using a different naming scheme (see ucom_tty_name()
 * callback) still use this unit allocation.
 */
static int
ucom_unit_alloc(void)
{
        int unit;

        /* sanity checks */
        if (ucom_unrhdr == NULL) {
                DPRINTF("ucom_unrhdr is NULL\n");
                return (-1);
        }
        unit = alloc_unr(ucom_unrhdr);
        DPRINTF("unit %d is allocated\n", unit);
        return (unit);
}

/*
 * Mark the unit number as not in use.
 */
static void
ucom_unit_free(int unit)
{
        /* sanity checks */
        if (unit < 0 || unit >= UCOM_UNIT_MAX || ucom_unrhdr == NULL) {
                DPRINTF("cannot free unit number\n");
                return;
        }
        DPRINTF("unit %d is freed\n", unit);
        free_unr(ucom_unrhdr, unit);
}

/*
 * Setup a group of one or more serial ports.
 *
 * The mutex pointed to by "mtx" is applied before all
 * callbacks are called back. Also "mtx" must be applied
 * before calling into the ucom-layer!
 */
int
ucom_attach(struct ucom_super_softc *ssc, struct ucom_softc *sc,
    int subunits, void *parent,
    const struct ucom_callback *callback, struct mtx *mtx)
{
        int subunit;
        int error = 0;

        if ((sc == NULL) ||
            (subunits <= 0) ||
            (callback == NULL) ||
            (mtx == NULL)) {
                return (EINVAL);
        }

        /* allocate a uniq unit number */
        ssc->sc_unit = ucom_unit_alloc();
        if (ssc->sc_unit == -1)
                return (ENOMEM);

        /* generate TTY name string */
        snprintf(ssc->sc_ttyname, sizeof(ssc->sc_ttyname),
            UCOM_TTY_PREFIX "%d", ssc->sc_unit);

        /* create USB request handling process */
        error = usb_proc_create(&ssc->sc_tq, mtx, "ucom", USB_PRI_MED);
        if (error) {
                ucom_unit_free(ssc->sc_unit);
                return (error);
        }
        ssc->sc_subunits = subunits;
        ssc->sc_flag = UCOM_FLAG_ATTACHED |
            UCOM_FLAG_FREE_UNIT | (ssc->sc_flag & UCOM_FLAG_DEVICE_MODE);

        if (callback->ucom_free == NULL)
                ssc->sc_flag |= UCOM_FLAG_WAIT_REFS;

        /* increment reference count */
        ucom_ref(ssc);

        for (subunit = 0; subunit < ssc->sc_subunits; subunit++) {
                sc[subunit].sc_subunit = subunit;
                sc[subunit].sc_super = ssc;
                sc[subunit].sc_mtx = mtx;
                sc[subunit].sc_parent = parent;
                sc[subunit].sc_callback = callback;

                error = ucom_attach_tty(ssc, &sc[subunit]);
                if (error) {
                        ucom_detach(ssc, &sc[0]);
                        return (error);
                }
                /* increment reference count */
                ucom_ref(ssc);

                /* set subunit attached */
                sc[subunit].sc_flag |= UCOM_FLAG_ATTACHED;
        }

        DPRINTF("tp = %p, unit = %d, subunits = %d\n",
                sc->sc_tty, ssc->sc_unit, ssc->sc_subunits);

        return (0);
}

/*
 * The following function will do nothing if the structure pointed to
 * by "ssc" and "sc" is zero or has already been detached.
 */
void
ucom_detach(struct ucom_super_softc *ssc, struct ucom_softc *sc)
{
        int subunit;

        if (!(ssc->sc_flag & UCOM_FLAG_ATTACHED))
                return;         /* not initialized */

        if (ssc->sc_sysctl_ttyname != NULL) {
                sysctl_remove_oid(ssc->sc_sysctl_ttyname, 1, 0);
                ssc->sc_sysctl_ttyname = NULL;
        }

        if (ssc->sc_sysctl_ttyports != NULL) {
                sysctl_remove_oid(ssc->sc_sysctl_ttyports, 1, 0);
                ssc->sc_sysctl_ttyports = NULL;
        }

        usb_proc_drain(&ssc->sc_tq);

        for (subunit = 0; subunit < ssc->sc_subunits; subunit++) {
                if (sc[subunit].sc_flag & UCOM_FLAG_ATTACHED) {
                        ucom_detach_tty(ssc, &sc[subunit]);

                        /* avoid duplicate detach */
                        sc[subunit].sc_flag &= ~UCOM_FLAG_ATTACHED;
                }
        }
        usb_proc_free(&ssc->sc_tq);

        ucom_unref(ssc);

        if (ssc->sc_flag & UCOM_FLAG_WAIT_REFS)
                ucom_drain(ssc);

        /* make sure we don't detach twice */
        ssc->sc_flag &= ~UCOM_FLAG_ATTACHED;
}

void
ucom_drain(struct ucom_super_softc *ssc)
{
        mtx_lock(&ucom_mtx);
        while (ssc->sc_refs > 0) {
                printf("ucom: Waiting for a TTY device to close.\n");
                usb_pause_mtx(&ucom_mtx, hz);
        }
        mtx_unlock(&ucom_mtx);
}

void
ucom_drain_all(void *arg)
{
        mtx_lock(&ucom_mtx);
        while (ucom_close_refs > 0) {
                printf("ucom: Waiting for all detached TTY "
                    "devices to have open fds closed.\n");
                usb_pause_mtx(&ucom_mtx, hz);
        }
        mtx_unlock(&ucom_mtx);
}

static cn_probe_t ucom_cnprobe;
static cn_init_t ucom_cninit;
static cn_term_t ucom_cnterm;
static cn_getc_t ucom_cngetc;
static cn_putc_t ucom_cnputc;
static cn_grab_t ucom_cngrab;
static cn_ungrab_t ucom_cnungrab;

const struct consdev_ops ucom_cnops = {
        .cn_probe       = ucom_cnprobe,
        .cn_init        = ucom_cninit,
        .cn_term        = ucom_cnterm,
        .cn_getc        = ucom_cngetc,
        .cn_putc        = ucom_cnputc,
        .cn_grab        = ucom_cngrab,
        .cn_ungrab      = ucom_cnungrab,
};

static int
ucom_attach_tty(struct ucom_super_softc *ssc, struct ucom_softc *sc)
{
        struct tty *tp;
        char buf[32];                   /* temporary TTY device name buffer */

        tp = tty_alloc_mutex(&ucom_class, sc, sc->sc_mtx);
        if (tp == NULL)
                return (ENOMEM);

        /* Check if the client has a custom TTY name */
        buf[0] = '\0';
        if (sc->sc_callback->ucom_tty_name) {
                sc->sc_callback->ucom_tty_name(sc, buf,
                    sizeof(buf), ssc->sc_unit, sc->sc_subunit);
        }
        if (buf[0] == 0) {
                /* Use default TTY name */
                if (ssc->sc_subunits > 1) {
                        /* multiple modems in one */
                        snprintf(buf, sizeof(buf), UCOM_TTY_PREFIX "%u.%u",
                            ssc->sc_unit, sc->sc_subunit);
                } else {
                        /* single modem */
                        snprintf(buf, sizeof(buf), UCOM_TTY_PREFIX "%u",
                            ssc->sc_unit);
                }
        }
        tty_makedev(tp, NULL, "%s", buf);

        sc->sc_tty = tp;

        sc->sc_pps.ppscap = PPS_CAPTUREBOTH;
        sc->sc_pps.driver_abi = PPS_ABI_VERSION;
        sc->sc_pps.driver_mtx = sc->sc_mtx;
        pps_init_abi(&sc->sc_pps);

        DPRINTF("ttycreate: %s\n", buf);

        /* Check if this device should be a console */
        if ((ucom_cons_softc == NULL) && 
            (ssc->sc_unit == ucom_cons_unit) &&
            (sc->sc_subunit == ucom_cons_subunit)) {
                DPRINTF("unit %d subunit %d is console",
                    ssc->sc_unit, sc->sc_subunit);

                ucom_cons_softc = sc;

                tty_init_console(tp, ucom_cons_baud);

                UCOM_MTX_LOCK(ucom_cons_softc);
                ucom_cons_rx_low = 0;
                ucom_cons_rx_high = 0;
                ucom_cons_tx_low = 0;
                ucom_cons_tx_high = 0;
                sc->sc_flag |= UCOM_FLAG_CONSOLE;
                ucom_open(ucom_cons_softc->sc_tty);
                ucom_param(ucom_cons_softc->sc_tty, &tp->t_termios_init_in);
                UCOM_MTX_UNLOCK(ucom_cons_softc);
        }

        if ((ssc->sc_flag & UCOM_FLAG_DEVICE_MODE) != 0 &&
            ucom_device_mode_console > 0 &&
            ucom_cons_softc == NULL) {
                struct consdev *cp;

                cp = malloc(sizeof(struct consdev), M_USBDEV,
                    M_WAITOK|M_ZERO);
                cp->cn_ops = &ucom_cnops;
                cp->cn_arg = NULL;
                cp->cn_pri = CN_NORMAL;
                strlcpy(cp->cn_name, "tty", sizeof(cp->cn_name));
                strlcat(cp->cn_name, buf, sizeof(cp->cn_name));

                sc->sc_consdev = cp;

                cnadd(cp);
        }

        return (0);
}

static void
ucom_detach_tty(struct ucom_super_softc *ssc, struct ucom_softc *sc)
{
        struct tty *tp = sc->sc_tty;

        DPRINTF("sc = %p, tp = %p\n", sc, sc->sc_tty);

        if (sc->sc_consdev != NULL) {
                cnremove(sc->sc_consdev);
                free(sc->sc_consdev, M_USBDEV);
                sc->sc_consdev = NULL;
        }

        if (sc->sc_flag & UCOM_FLAG_CONSOLE) {
                UCOM_MTX_LOCK(ucom_cons_softc);
                ucom_close(ucom_cons_softc->sc_tty);
                sc->sc_flag &= ~UCOM_FLAG_CONSOLE;
                UCOM_MTX_UNLOCK(ucom_cons_softc);
                ucom_cons_softc = NULL;
        }

        /* the config thread has been stopped when we get here */

        UCOM_MTX_LOCK(sc);
        sc->sc_flag |= UCOM_FLAG_GONE;
        sc->sc_flag &= ~(UCOM_FLAG_HL_READY | UCOM_FLAG_LL_READY);
        UCOM_MTX_UNLOCK(sc);

        if (tp) {
                mtx_lock(&ucom_mtx);
                ucom_close_refs++;
                mtx_unlock(&ucom_mtx);

                tty_lock(tp);

                ucom_close(tp); /* close, if any */

                tty_rel_gone(tp);

                UCOM_MTX_LOCK(sc);
                /*
                 * make sure that read and write transfers are stopped
                 */
                if (sc->sc_callback->ucom_stop_read)
                        (sc->sc_callback->ucom_stop_read) (sc);
                if (sc->sc_callback->ucom_stop_write)
                        (sc->sc_callback->ucom_stop_write) (sc);
                UCOM_MTX_UNLOCK(sc);
        }
}

void
ucom_set_pnpinfo_usb(struct ucom_super_softc *ssc, device_t dev)
{
        char buf[64];
        uint8_t iface_index;
        struct usb_attach_arg *uaa;

        snprintf(buf, sizeof(buf), "ttyname=" UCOM_TTY_PREFIX
            "%d ttyports=%d", ssc->sc_unit, ssc->sc_subunits);

        /* Store the PNP info in the first interface for the device */
        uaa = device_get_ivars(dev);
        iface_index = uaa->info.bIfaceIndex;
    
        if (usbd_set_pnpinfo(uaa->device, iface_index, buf) != 0)
                device_printf(dev, "Could not set PNP info\n");

        /*
         * The following information is also replicated in the PNP-info
         * string which is registered above:
         */
        if (ssc->sc_sysctl_ttyname == NULL) {
                ssc->sc_sysctl_ttyname = SYSCTL_ADD_STRING(NULL,
                    SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
                    OID_AUTO, "ttyname", CTLFLAG_RD, ssc->sc_ttyname, 0,
                    "TTY device basename");
        }
        if (ssc->sc_sysctl_ttyports == NULL) {
                ssc->sc_sysctl_ttyports = SYSCTL_ADD_INT(NULL,
                    SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
                    OID_AUTO, "ttyports", CTLFLAG_RD,
                    NULL, ssc->sc_subunits, "Number of ports");
        }
}

void
ucom_set_usb_mode(struct ucom_super_softc *ssc, enum usb_hc_mode usb_mode)
{

        switch (usb_mode) {
        case USB_MODE_DEVICE:
                ssc->sc_flag |= UCOM_FLAG_DEVICE_MODE;
                break;
        default:
                ssc->sc_flag &= ~UCOM_FLAG_DEVICE_MODE;
                break;
        }
}

static void
ucom_command_barrier_cb(struct usb_proc_msg *msg __unused)
{
        /* NOP */
}

/*
 * ucom_command_barrier inserts a dummy task and waits for it so that we can be
 * certain that previously enqueued tasks are finished before returning back to
 * the tty layer.
 */
static int
ucom_command_barrier(struct ucom_softc *sc)
{
        struct ucom_super_softc *ssc = sc->sc_super;
        struct usb_proc_msg dummy = { .pm_callback = ucom_command_barrier_cb };
        struct usb_proc_msg *task;
        int error;

        UCOM_MTX_ASSERT(sc, MA_OWNED);

        if (usb_proc_is_gone(&ssc->sc_tq)) {
                DPRINTF("proc is gone\n");
                return (ENXIO);         /* nothing to do */
        }

        task = usb_proc_msignal(&ssc->sc_tq, &dummy, &dummy);
        error = usb_proc_mwait_sig(&ssc->sc_tq, task, task);
        if (error == 0 && sc->sc_tty != NULL && tty_gone(sc->sc_tty))
                error = ENXIO;
        return (error);
}

static int
ucom_queue_command(struct ucom_softc *sc,
    usb_proc_callback_t *fn, struct termios *pt,
    struct usb_proc_msg *t0, struct usb_proc_msg *t1, bool wait)
{
        struct ucom_super_softc *ssc = sc->sc_super;
        struct ucom_param_task *task;
        int error;

        UCOM_MTX_ASSERT(sc, MA_OWNED);

        if (usb_proc_is_gone(&ssc->sc_tq)) {
                DPRINTF("proc is gone\n");
                return (ENXIO);         /* nothing to do */
        }
        /* 
         * NOTE: The task cannot get executed before we drop the
         * "sc_mtx" mutex. It is safe to update fields in the message
         * structure after that the message got queued.
         */
        task = (struct ucom_param_task *)
          usb_proc_msignal(&ssc->sc_tq, t0, t1);

        /* Setup callback and softc pointers */
        task->hdr.pm_callback = fn;
        task->sc = sc;

        /* 
         * Make a copy of the termios. This field is only present if
         * the "pt" field is not NULL.
         */
        if (pt != NULL)
                task->termios_copy = *pt;

        /*
         * Closing or opening the device should be synchronous.
         */
        if (wait) {
                error = usb_proc_mwait_sig(&ssc->sc_tq, t0, t1);

                /* usb_proc_mwait_sig may have dropped the tty lock. */
                if (error == 0 && sc->sc_tty != NULL && tty_gone(sc->sc_tty))
                        error = ENXIO;
        } else {
                error = 0;
        }

        /*
         * In case of multiple configure requests,
         * keep track of the last one!
         */
        if (fn == ucom_cfg_start_transfers)
                sc->sc_last_start_xfer = &task->hdr;

        return (error);
}

static void
ucom_shutdown(struct ucom_softc *sc)
{
        struct tty *tp = sc->sc_tty;

        UCOM_MTX_ASSERT(sc, MA_OWNED);

        DPRINTF("\n");

        /*
         * Hang up if necessary:
         */
        if (tp->t_termios.c_cflag & HUPCL) {
                ucom_modem(tp, 0, SER_DTR);
        }
}

/*
 * Return values:
 *    0: normal
 * else: taskqueue is draining or gone
 */
uint8_t
ucom_cfg_is_gone(struct ucom_softc *sc)
{
        struct ucom_super_softc *ssc = sc->sc_super;

        return (usb_proc_is_gone(&ssc->sc_tq));
}

static void
ucom_cfg_start_transfers(struct usb_proc_msg *_task)
{
        struct ucom_cfg_task *task = 
            (struct ucom_cfg_task *)_task;
        struct ucom_softc *sc = task->sc;

        if (!(sc->sc_flag & UCOM_FLAG_LL_READY)) {
                return;
        }
        if (!(sc->sc_flag & UCOM_FLAG_HL_READY)) {
                /* TTY device closed */
                return;
        }

        if (_task == sc->sc_last_start_xfer)
                sc->sc_flag |= UCOM_FLAG_GP_DATA;

        if (sc->sc_callback->ucom_start_read) {
                (sc->sc_callback->ucom_start_read) (sc);
        }
        if (sc->sc_callback->ucom_start_write) {
                (sc->sc_callback->ucom_start_write) (sc);
        }
}

static void
ucom_start_transfers(struct ucom_softc *sc)
{
        if (!(sc->sc_flag & UCOM_FLAG_HL_READY)) {
                return;
        }
        /*
         * Make sure that data transfers are started in both
         * directions:
         */
        if (sc->sc_callback->ucom_start_read) {
                (sc->sc_callback->ucom_start_read) (sc);
        }
        if (sc->sc_callback->ucom_start_write) {
                (sc->sc_callback->ucom_start_write) (sc);
        }
}

static void
ucom_cfg_open(struct usb_proc_msg *_task)
{
        struct ucom_cfg_task *task = 
            (struct ucom_cfg_task *)_task;
        struct ucom_softc *sc = task->sc;

        DPRINTF("\n");

        if (sc->sc_flag & UCOM_FLAG_LL_READY) {
                /* already opened */

        } else {
                sc->sc_flag |= UCOM_FLAG_LL_READY;

                if (sc->sc_callback->ucom_cfg_open) {
                        (sc->sc_callback->ucom_cfg_open) (sc);

                        /* wait a little */
                        usb_pause_mtx(sc->sc_mtx, hz / 10);
                }
        }
}

static int
ucom_open(struct tty *tp)
{
        struct ucom_softc *sc = tty_softc(tp);
        int error;

        UCOM_MTX_ASSERT(sc, MA_OWNED);

        if (sc->sc_flag & UCOM_FLAG_GONE) {
                return (ENXIO);
        }
        if (sc->sc_flag & UCOM_FLAG_HL_READY) {
                /* already opened */
                return (0);
        }
        DPRINTF("tp = %p\n", tp);

        if (sc->sc_callback->ucom_pre_open) {
                /*
                 * give the lower layer a chance to disallow TTY open, for
                 * example if the device is not present:
                 */
                error = (sc->sc_callback->ucom_pre_open) (sc);
                if (error != 0)
                        goto out;
        }
        sc->sc_flag |= UCOM_FLAG_HL_READY;

        /* Disable transfers */
        sc->sc_flag &= ~UCOM_FLAG_GP_DATA;

        sc->sc_lsr = 0;
        sc->sc_msr = 0;
        sc->sc_mcr = 0;

        /* reset programmed line state */
        sc->sc_pls_curr = 0;
        sc->sc_pls_set = 0;
        sc->sc_pls_clr = 0;

        /* reset jitter buffer */
        sc->sc_jitterbuf_in = 0;
        sc->sc_jitterbuf_out = 0;

        error = ucom_queue_command(sc, ucom_cfg_open, NULL,
            &sc->sc_open_task[0].hdr,
            &sc->sc_open_task[1].hdr, true);
        if (error != 0)
                goto out;

        /*
         * Queue transfer enable command last, we'll have a barrier later so we
         * don't need to wait on this to complete specifically.
         */
        error = ucom_queue_command(sc, ucom_cfg_start_transfers, NULL,
            &sc->sc_start_task[0].hdr,
            &sc->sc_start_task[1].hdr, true);
        if (error != 0)
                goto out;

        if (sc->sc_tty == NULL || (sc->sc_tty->t_termios.c_cflag & CNO_RTSDTR) == 0)
                ucom_modem(tp, SER_DTR | SER_RTS, 0);

        ucom_ring(sc, 0);

        ucom_break(sc, 0);

        ucom_status_change(sc);

        error = ucom_command_barrier(sc);
out:
        return (error);
}

static void
ucom_cfg_close(struct usb_proc_msg *_task)
{
        struct ucom_cfg_task *task = 
            (struct ucom_cfg_task *)_task;
        struct ucom_softc *sc = task->sc;

        DPRINTF("\n");

        if (sc->sc_flag & UCOM_FLAG_LL_READY) {
                sc->sc_flag &= ~UCOM_FLAG_LL_READY;
                if (sc->sc_callback->ucom_cfg_close)
                        (sc->sc_callback->ucom_cfg_close) (sc);
        } else {
                /* already closed */
        }
}

static void
ucom_close(struct tty *tp)
{
        struct ucom_softc *sc = tty_softc(tp);

        UCOM_MTX_ASSERT(sc, MA_OWNED);

        DPRINTF("tp=%p\n", tp);

        if (!(sc->sc_flag & UCOM_FLAG_HL_READY)) {
                DPRINTF("tp=%p already closed\n", tp);
                return;
        }
        ucom_shutdown(sc);

        (void)ucom_queue_command(sc, ucom_cfg_close, NULL,
            &sc->sc_close_task[0].hdr,
            &sc->sc_close_task[1].hdr, true);

        sc->sc_flag &= ~(UCOM_FLAG_HL_READY | UCOM_FLAG_RTS_IFLOW);

        if (sc->sc_callback->ucom_stop_read) {
                (sc->sc_callback->ucom_stop_read) (sc);
        }
}

static void
ucom_inwakeup(struct tty *tp)
{
        struct ucom_softc *sc = tty_softc(tp);
        uint16_t pos;

        if (sc == NULL)
                return;

        UCOM_MTX_ASSERT(sc, MA_OWNED);

        DPRINTF("tp=%p\n", tp);

        if (ttydisc_can_bypass(tp) != 0 || 
            (sc->sc_flag & UCOM_FLAG_HL_READY) == 0 ||
            (sc->sc_flag & UCOM_FLAG_INWAKEUP) != 0) {
                return;
        }

        /* prevent recursion */
        sc->sc_flag |= UCOM_FLAG_INWAKEUP;

        pos = sc->sc_jitterbuf_out;

        while (sc->sc_jitterbuf_in != pos) {
                int c;

                c = (char)sc->sc_jitterbuf[pos];

                if (ttydisc_rint(tp, c, 0) == -1)
                        break;
                pos++;
                if (pos >= UCOM_JITTERBUF_SIZE)
                        pos -= UCOM_JITTERBUF_SIZE;
        }

        sc->sc_jitterbuf_out = pos;

        /* clear RTS in async fashion */
        if ((sc->sc_jitterbuf_in == pos) && 
            (sc->sc_flag & UCOM_FLAG_RTS_IFLOW))
                ucom_rts(sc, 0);

        sc->sc_flag &= ~UCOM_FLAG_INWAKEUP;
}

static int
ucom_ioctl(struct tty *tp, u_long cmd, caddr_t data, struct thread *td)
{
        struct ucom_softc *sc = tty_softc(tp);
        int error;

        UCOM_MTX_ASSERT(sc, MA_OWNED);

        if (!(sc->sc_flag & UCOM_FLAG_HL_READY)) {
                return (EIO);
        }
        DPRINTF("cmd = 0x%08lx\n", cmd);

        switch (cmd) {
#if 0
        case TIOCSRING:
                ucom_ring(sc, 1);
                error = 0;
                break;
        case TIOCCRING:
                ucom_ring(sc, 0);
                error = 0;
                break;
#endif
        case TIOCSBRK:
                ucom_break(sc, 1);
                error = ucom_command_barrier(sc);
                if (error == ENXIO)
                        error = ENODEV;
                break;
        case TIOCCBRK:
                ucom_break(sc, 0);
                error = ucom_command_barrier(sc);
                if (error == ENXIO)
                        error = ENODEV;
                break;
        default:
                if (sc->sc_callback->ucom_ioctl) {
                        error = (sc->sc_callback->ucom_ioctl)
                            (sc, cmd, data, 0, td);
                } else {
                        error = ENOIOCTL;
                }
                if (error == ENOIOCTL)
                        error = pps_ioctl(cmd, data, &sc->sc_pps);
                break;
        }
        return (error);
}

static int
ucom_modem(struct tty *tp, int sigon, int sigoff)
{
        struct ucom_softc *sc = tty_softc(tp);
        uint8_t onoff;

        UCOM_MTX_ASSERT(sc, MA_OWNED);

        if (!(sc->sc_flag & UCOM_FLAG_HL_READY)) {
                return (0);
        }
        if ((sigon == 0) && (sigoff == 0)) {
                if (sc->sc_mcr & SER_DTR) {
                        sigon |= SER_DTR;
                }
                if (sc->sc_mcr & SER_RTS) {
                        sigon |= SER_RTS;
                }
                if (sc->sc_msr & SER_CTS) {
                        sigon |= SER_CTS;
                }
                if (sc->sc_msr & SER_DCD) {
                        sigon |= SER_DCD;
                }
                if (sc->sc_msr & SER_DSR) {
                        sigon |= SER_DSR;
                }
                if (sc->sc_msr & SER_RI) {
                        sigon |= SER_RI;
                }
                return (sigon);
        }
        if (sigon & SER_DTR) {
                sc->sc_mcr |= SER_DTR;
        }
        if (sigoff & SER_DTR) {
                sc->sc_mcr &= ~SER_DTR;
        }
        if (sigon & SER_RTS) {
                sc->sc_mcr |= SER_RTS;
        }
        if (sigoff & SER_RTS) {
                sc->sc_mcr &= ~SER_RTS;
        }
        onoff = (sc->sc_mcr & SER_DTR) ? 1 : 0;
        ucom_dtr(sc, onoff);

        onoff = (sc->sc_mcr & SER_RTS) ? 1 : 0;
        ucom_rts(sc, onoff);

        return (0);
}

static void
ucom_cfg_line_state(struct usb_proc_msg *_task)
{
        struct ucom_cfg_task *task = 
            (struct ucom_cfg_task *)_task;
        struct ucom_softc *sc = task->sc;
        uint8_t notch_bits;
        uint8_t any_bits;
        uint8_t prev_value;
        uint8_t last_value;
        uint8_t mask;

        if (!(sc->sc_flag & UCOM_FLAG_LL_READY)) {
                return;
        }

        mask = 0;
        /* compute callback mask */
        if (sc->sc_callback->ucom_cfg_set_dtr)
                mask |= UCOM_LS_DTR;
        if (sc->sc_callback->ucom_cfg_set_rts)
                mask |= UCOM_LS_RTS;
        if (sc->sc_callback->ucom_cfg_set_break)
                mask |= UCOM_LS_BREAK;
        if (sc->sc_callback->ucom_cfg_set_ring)
                mask |= UCOM_LS_RING;

        /* compute the bits we are to program */
        notch_bits = (sc->sc_pls_set & sc->sc_pls_clr) & mask;
        any_bits = (sc->sc_pls_set | sc->sc_pls_clr) & mask;
        prev_value = sc->sc_pls_curr ^ notch_bits;
        last_value = sc->sc_pls_curr;

        /* reset programmed line state */
        sc->sc_pls_curr = 0;
        sc->sc_pls_set = 0;
        sc->sc_pls_clr = 0;

        /* ensure that we don't lose any levels */
        if (notch_bits & UCOM_LS_DTR)
                sc->sc_callback->ucom_cfg_set_dtr(sc,
                    (prev_value & UCOM_LS_DTR) ? 1 : 0);
        if (notch_bits & UCOM_LS_RTS)
                sc->sc_callback->ucom_cfg_set_rts(sc,
                    (prev_value & UCOM_LS_RTS) ? 1 : 0);
        if (notch_bits & UCOM_LS_BREAK)
                sc->sc_callback->ucom_cfg_set_break(sc,
                    (prev_value & UCOM_LS_BREAK) ? 1 : 0);
        if (notch_bits & UCOM_LS_RING)
                sc->sc_callback->ucom_cfg_set_ring(sc,
                    (prev_value & UCOM_LS_RING) ? 1 : 0);

        /* set last value */
        if (any_bits & UCOM_LS_DTR)
                sc->sc_callback->ucom_cfg_set_dtr(sc,
                    (last_value & UCOM_LS_DTR) ? 1 : 0);
        if (any_bits & UCOM_LS_RTS)
                sc->sc_callback->ucom_cfg_set_rts(sc,
                    (last_value & UCOM_LS_RTS) ? 1 : 0);
        if (any_bits & UCOM_LS_BREAK)
                sc->sc_callback->ucom_cfg_set_break(sc,
                    (last_value & UCOM_LS_BREAK) ? 1 : 0);
        if (any_bits & UCOM_LS_RING)
                sc->sc_callback->ucom_cfg_set_ring(sc,
                    (last_value & UCOM_LS_RING) ? 1 : 0);
}

static void
ucom_line_state(struct ucom_softc *sc,
    uint8_t set_bits, uint8_t clear_bits)
{
        UCOM_MTX_ASSERT(sc, MA_OWNED);

        if (!(sc->sc_flag & UCOM_FLAG_HL_READY)) {
                return;
        }

        DPRINTF("on=0x%02x, off=0x%02x\n", set_bits, clear_bits);

        /* update current programmed line state */
        sc->sc_pls_curr |= set_bits;
        sc->sc_pls_curr &= ~clear_bits;
        sc->sc_pls_set |= set_bits;
        sc->sc_pls_clr |= clear_bits;

        /*
         * defer driver programming - we don't propagate any error from
         * this call because we'll catch such errors further up the call stack.
         */
        (void)ucom_queue_command(sc, ucom_cfg_line_state, NULL,
            &sc->sc_line_state_task[0].hdr,
            &sc->sc_line_state_task[1].hdr, false);
}

static void
ucom_ring(struct ucom_softc *sc, uint8_t onoff)
{
        DPRINTF("onoff = %d\n", onoff);

        if (onoff)
                ucom_line_state(sc, UCOM_LS_RING, 0);
        else
                ucom_line_state(sc, 0, UCOM_LS_RING);
}

static void
ucom_break(struct ucom_softc *sc, uint8_t onoff)
{
        DPRINTF("onoff = %d\n", onoff);

        if (onoff)
                ucom_line_state(sc, UCOM_LS_BREAK, 0);
        else
                ucom_line_state(sc, 0, UCOM_LS_BREAK);
}

static void
ucom_dtr(struct ucom_softc *sc, uint8_t onoff)
{
        DPRINTF("onoff = %d\n", onoff);

        if (onoff)
                ucom_line_state(sc, UCOM_LS_DTR, 0);
        else
                ucom_line_state(sc, 0, UCOM_LS_DTR);
}

static void
ucom_rts(struct ucom_softc *sc, uint8_t onoff)
{
        DPRINTF("onoff = %d\n", onoff);

        if (onoff)
                ucom_line_state(sc, UCOM_LS_RTS, 0);
        else
                ucom_line_state(sc, 0, UCOM_LS_RTS);
}

static void
ucom_cfg_status_change(struct usb_proc_msg *_task)
{
        struct ucom_cfg_task *task = 
            (struct ucom_cfg_task *)_task;
        struct ucom_softc *sc = task->sc;
        struct tty *tp;
        int onoff;
        uint8_t new_msr;
        uint8_t new_lsr;
        uint8_t msr_delta;
        uint8_t lsr_delta;
        uint8_t pps_signal;

        tp = sc->sc_tty;

        UCOM_MTX_ASSERT(sc, MA_OWNED);

        if (!(sc->sc_flag & UCOM_FLAG_LL_READY)) {
                return;
        }
        if (sc->sc_callback->ucom_cfg_get_status == NULL) {
                return;
        }
        /* get status */

        new_msr = 0;
        new_lsr = 0;

        (sc->sc_callback->ucom_cfg_get_status) (sc, &new_lsr, &new_msr);

        if (!(sc->sc_flag & UCOM_FLAG_HL_READY)) {
                /* TTY device closed */
                return;
        }
        msr_delta = (sc->sc_msr ^ new_msr);
        lsr_delta = (sc->sc_lsr ^ new_lsr);

        sc->sc_msr = new_msr;
        sc->sc_lsr = new_lsr;

        /*
         * Time pulse counting support.
         */
        switch(ucom_pps_mode & UART_PPS_SIGNAL_MASK) {
        case UART_PPS_CTS:
                pps_signal = SER_CTS;
                break;
        case UART_PPS_DCD:
                pps_signal = SER_DCD;
                break;
        default:
                pps_signal = 0;
                break;
        }

        if ((sc->sc_pps.ppsparam.mode & PPS_CAPTUREBOTH) &&
            (msr_delta & pps_signal)) {
                pps_capture(&sc->sc_pps);
                onoff = (sc->sc_msr & pps_signal) ? 1 : 0;
                if (ucom_pps_mode & UART_PPS_INVERT_PULSE)
                        onoff = !onoff;
                pps_event(&sc->sc_pps, onoff ? PPS_CAPTUREASSERT :
                    PPS_CAPTURECLEAR);
        }

        if (msr_delta & SER_DCD) {
                onoff = (sc->sc_msr & SER_DCD) ? 1 : 0;

                DPRINTF("DCD changed to %d\n", onoff);

                ttydisc_modem(tp, onoff);
        }

        if ((lsr_delta & ULSR_BI) && (sc->sc_lsr & ULSR_BI)) {
                DPRINTF("BREAK detected\n");

                ttydisc_rint(tp, 0, TRE_BREAK);
                ttydisc_rint_done(tp);
        }

        if ((lsr_delta & ULSR_FE) && (sc->sc_lsr & ULSR_FE)) {
                DPRINTF("Frame error detected\n");

                ttydisc_rint(tp, 0, TRE_FRAMING);
                ttydisc_rint_done(tp);
        }

        if ((lsr_delta & ULSR_PE) && (sc->sc_lsr & ULSR_PE)) {
                DPRINTF("Parity error detected\n");

                ttydisc_rint(tp, 0, TRE_PARITY);
                ttydisc_rint_done(tp);
        }
}

void
ucom_status_change(struct ucom_softc *sc)
{
        UCOM_MTX_ASSERT(sc, MA_OWNED);

        if (sc->sc_flag & UCOM_FLAG_CONSOLE)
                return;         /* not supported */

        if (!(sc->sc_flag & UCOM_FLAG_HL_READY)) {
                return;
        }
        DPRINTF("\n");

        (void)ucom_queue_command(sc, ucom_cfg_status_change, NULL,
            &sc->sc_status_task[0].hdr,
            &sc->sc_status_task[1].hdr, true);
}

static void
ucom_cfg_param(struct usb_proc_msg *_task)
{
        struct ucom_param_task *task = 
            (struct ucom_param_task *)_task;
        struct ucom_softc *sc = task->sc;

        if (!(sc->sc_flag & UCOM_FLAG_LL_READY)) {
                return;
        }
        if (sc->sc_callback->ucom_cfg_param == NULL) {
                return;
        }

        (sc->sc_callback->ucom_cfg_param) (sc, &task->termios_copy);

        /* wait a little */
        usb_pause_mtx(sc->sc_mtx, hz / 10);
}

static int
ucom_param(struct tty *tp, struct termios *t)
{
        struct ucom_softc *sc = tty_softc(tp);
        uint8_t opened;
        int error;

        UCOM_MTX_ASSERT(sc, MA_OWNED);

        opened = 0;
        error = 0;

        if (!(sc->sc_flag & UCOM_FLAG_HL_READY)) {
                /* XXX the TTY layer should call "open()" first! */
                /*
                 * Not quite: Its ordering is partly backwards, but
                 * some parameters must be set early in ttydev_open(),
                 * possibly before calling ttydevsw_open().
                 */
                error = ucom_open(tp);
                if (error)
                        goto done;

                opened = 1;
        }
        DPRINTF("sc = %p\n", sc);

        /* Check requested parameters. */
        if (t->c_ispeed && (t->c_ispeed != t->c_ospeed)) {
                /* XXX c_ospeed == 0 is perfectly valid. */
                DPRINTF("mismatch ispeed and ospeed\n");
                error = EINVAL;
                goto done;
        }
        t->c_ispeed = t->c_ospeed;

        if (sc->sc_callback->ucom_pre_param) {
                /* Let the lower layer verify the parameters */
                error = (sc->sc_callback->ucom_pre_param) (sc, t);
                if (error) {
                        DPRINTF("callback error = %d\n", error);
                        goto done;
                }
        }

        /* Disable transfers */
        sc->sc_flag &= ~UCOM_FLAG_GP_DATA;

        /* Queue baud rate programming command first */
        error = ucom_queue_command(sc, ucom_cfg_param, t,
            &sc->sc_param_task[0].hdr,
            &sc->sc_param_task[1].hdr, true);
        if (error != 0)
                goto done;

        /* Queue transfer enable command last */
        error = ucom_queue_command(sc, ucom_cfg_start_transfers, NULL,
            &sc->sc_start_task[0].hdr,
            &sc->sc_start_task[1].hdr, true);
        if (error != 0)
                goto done;

        if (t->c_cflag & CRTS_IFLOW) {
                sc->sc_flag |= UCOM_FLAG_RTS_IFLOW;
        } else if (sc->sc_flag & UCOM_FLAG_RTS_IFLOW) {
                sc->sc_flag &= ~UCOM_FLAG_RTS_IFLOW;
                ucom_modem(tp, SER_RTS, 0);
        }

        error = ucom_command_barrier(sc);
done:
        if (error) {
                if (opened) {
                        ucom_close(tp);
                }
        }
        return (error);
}

static void
ucom_outwakeup(struct tty *tp)
{
        struct ucom_softc *sc = tty_softc(tp);

        UCOM_MTX_ASSERT(sc, MA_OWNED);

        DPRINTF("sc = %p\n", sc);

        if (!(sc->sc_flag & UCOM_FLAG_HL_READY)) {
                /* The higher layer is not ready */
                return;
        }
        ucom_start_transfers(sc);
}

static bool
ucom_busy(struct tty *tp)
{
        struct ucom_softc *sc = tty_softc(tp);
        const uint8_t txidle = ULSR_TXRDY | ULSR_TSRE;

        UCOM_MTX_ASSERT(sc, MA_OWNED);

        DPRINTFN(3, "sc = %p lsr 0x%02x\n", sc, sc->sc_lsr);

        /*
         * If the driver maintains the txidle bits in LSR, we can use them to
         * determine whether the transmitter is busy or idle.  Otherwise we have
         * to assume it is idle to avoid hanging forever on tcdrain(3).
         */
        if (sc->sc_flag & UCOM_FLAG_LSRTXIDLE)
                return ((sc->sc_lsr & txidle) != txidle);
        else
                return (false);
}

/*------------------------------------------------------------------------*
 *      ucom_get_data
 *
 * Return values:
 * 0: No data is available.
 * Else: Data is available.
 *------------------------------------------------------------------------*/
uint8_t
ucom_get_data(struct ucom_softc *sc, struct usb_page_cache *pc,
    uint32_t offset, uint32_t len, uint32_t *actlen)
{
        struct usb_page_search res;
        struct tty *tp = sc->sc_tty;
        uint32_t cnt;
        uint32_t offset_orig;

        UCOM_MTX_ASSERT(sc, MA_OWNED);

        if (sc->sc_flag & UCOM_FLAG_CONSOLE) {
                unsigned temp;

                /* get total TX length */

                temp = ucom_cons_tx_high - ucom_cons_tx_low;
                temp %= UCOM_CONS_BUFSIZE;

                /* limit TX length */

                if (temp > (UCOM_CONS_BUFSIZE - ucom_cons_tx_low))
                        temp = (UCOM_CONS_BUFSIZE - ucom_cons_tx_low);

                if (temp > len)
                        temp = len;

                /* copy in data */

                usbd_copy_in(pc, offset, ucom_cons_tx_buf + ucom_cons_tx_low, temp);

                /* update counters */

                ucom_cons_tx_low += temp;
                ucom_cons_tx_low %= UCOM_CONS_BUFSIZE;

                /* store actual length */

                *actlen = temp;

                return (temp ? 1 : 0);
        }

        if (tty_gone(tp) ||
            !(sc->sc_flag & UCOM_FLAG_GP_DATA)) {
                actlen[0] = 0;
                return (0);             /* multiport device polling */
        }
        offset_orig = offset;

        while (len != 0) {
                usbd_get_page(pc, offset, &res);

                if (res.length > len) {
                        res.length = len;
                }
                /* copy data directly into USB buffer */
                cnt = ttydisc_getc(tp, res.buffer, res.length);

                offset += cnt;
                len -= cnt;

                if (cnt < res.length) {
                        /* end of buffer */
                        break;
                }
        }

        actlen[0] = offset - offset_orig;

        DPRINTF("cnt=%d\n", actlen[0]);

        if (actlen[0] == 0) {
                return (0);
        }
        return (1);
}

void
ucom_put_data(struct ucom_softc *sc, struct usb_page_cache *pc,
    uint32_t offset, uint32_t len)
{
        struct usb_page_search res;
        struct tty *tp = sc->sc_tty;
        char *buf;
        uint32_t cnt;

        UCOM_MTX_ASSERT(sc, MA_OWNED);

        if (sc->sc_flag & UCOM_FLAG_CONSOLE) {
                unsigned temp;

                /* get maximum RX length */

                temp = (UCOM_CONS_BUFSIZE - 1) - ucom_cons_rx_high + ucom_cons_rx_low;
                temp %= UCOM_CONS_BUFSIZE;

                /* limit RX length */

                if (temp > (UCOM_CONS_BUFSIZE - ucom_cons_rx_high))
                        temp = (UCOM_CONS_BUFSIZE - ucom_cons_rx_high);

                if (temp > len)
                        temp = len;

                /* copy out data */

                usbd_copy_out(pc, offset, ucom_cons_rx_buf + ucom_cons_rx_high, temp);

                /* update counters */

                ucom_cons_rx_high += temp;
                ucom_cons_rx_high %= UCOM_CONS_BUFSIZE;

                return;
        }

        if (tty_gone(tp))
                return;                 /* multiport device polling */

        if (len == 0)
                return;                 /* no data */

        /* set a flag to prevent recursation ? */

        while (len > 0) {
                usbd_get_page(pc, offset, &res);

                if (res.length > len) {
                        res.length = len;
                }
                len -= res.length;
                offset += res.length;

                /* pass characters to tty layer */

                buf = res.buffer;
                cnt = res.length;

                /* first check if we can pass the buffer directly */

                if (ttydisc_can_bypass(tp)) {
                        /* clear any jitter buffer */
                        sc->sc_jitterbuf_in = 0;
                        sc->sc_jitterbuf_out = 0;

                        if (ttydisc_rint_bypass(tp, buf, cnt) != cnt) {
                                DPRINTF("tp=%p, data lost\n", tp);
                        }
                        continue;
                }
                /* need to loop */

                for (cnt = 0; cnt != res.length; cnt++) {
                        if (sc->sc_jitterbuf_in != sc->sc_jitterbuf_out ||
                            ttydisc_rint(tp, buf[cnt], 0) == -1) {
                                uint16_t end;
                                uint16_t pos;

                                pos = sc->sc_jitterbuf_in;
                                end = sc->sc_jitterbuf_out +
                                    UCOM_JITTERBUF_SIZE - 1;
                                if (end >= UCOM_JITTERBUF_SIZE)
                                        end -= UCOM_JITTERBUF_SIZE;

                                for (; cnt != res.length; cnt++) {
                                        if (pos == end)
                                                break;
                                        sc->sc_jitterbuf[pos] = buf[cnt];
                                        pos++;
                                        if (pos >= UCOM_JITTERBUF_SIZE)
                                                pos -= UCOM_JITTERBUF_SIZE;
                                }

                                sc->sc_jitterbuf_in = pos;

                                /* set RTS in async fashion */
                                if (sc->sc_flag & UCOM_FLAG_RTS_IFLOW)
                                        ucom_rts(sc, 1);

                                DPRINTF("tp=%p, lost %d "
                                    "chars\n", tp, res.length - cnt);
                                break;
                        }
                }
        }
        ttydisc_rint_done(tp);
}

static void
ucom_free(void *xsc)
{
        struct ucom_softc *sc = xsc;

        if (sc->sc_callback->ucom_free != NULL)
                sc->sc_callback->ucom_free(sc);
        else
                ucom_unref(sc->sc_super);

        mtx_lock(&ucom_mtx);
        ucom_close_refs--;
        mtx_unlock(&ucom_mtx);
}

CONSOLE_DRIVER(ucom);

static void
ucom_cnprobe(struct consdev  *cp)
{
        if (ucom_cons_unit != -1)
                cp->cn_pri = CN_NORMAL;
        else
                cp->cn_pri = CN_DEAD;

        strlcpy(cp->cn_name, "ucom", sizeof(cp->cn_name));
}

static void
ucom_cninit(struct consdev  *cp)
{
}

static void
ucom_cnterm(struct consdev  *cp)
{
}

static void
ucom_cngrab(struct consdev *cp)
{
}

static void
ucom_cnungrab(struct consdev *cp)
{
}

static int
ucom_cngetc(struct consdev *cd)
{
        struct ucom_softc *sc = ucom_cons_softc;
        int c;

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

        UCOM_MTX_LOCK(sc);

        if (ucom_cons_rx_low != ucom_cons_rx_high) {
                c = ucom_cons_rx_buf[ucom_cons_rx_low];
                ucom_cons_rx_low ++;
                ucom_cons_rx_low %= UCOM_CONS_BUFSIZE;
        } else {
                c = -1;
        }

        /* start USB transfers */
        ucom_outwakeup(sc->sc_tty);

        UCOM_MTX_UNLOCK(sc);

        /* poll if necessary */
        if (USB_IN_POLLING_MODE_FUNC() && sc->sc_callback->ucom_poll)
                (sc->sc_callback->ucom_poll) (sc);

        return (c);
}

static void
ucom_cnputc(struct consdev *cd, int c)
{
        struct ucom_softc *sc = ucom_cons_softc;
        unsigned temp;

        if (sc == NULL)
                return;

 repeat:

        UCOM_MTX_LOCK(sc);

        /* compute maximum TX length */

        temp = (UCOM_CONS_BUFSIZE - 1) - ucom_cons_tx_high + ucom_cons_tx_low;
        temp %= UCOM_CONS_BUFSIZE;

        if (temp) {
                ucom_cons_tx_buf[ucom_cons_tx_high] = c;
                ucom_cons_tx_high ++;
                ucom_cons_tx_high %= UCOM_CONS_BUFSIZE;
        }

        /* start USB transfers */
        ucom_outwakeup(sc->sc_tty);

        UCOM_MTX_UNLOCK(sc);

        /* poll if necessary */
        if (USB_IN_POLLING_MODE_FUNC() && sc->sc_callback->ucom_poll) {
                (sc->sc_callback->ucom_poll) (sc);
                /* simple flow control */
                if (temp == 0)
                        goto repeat;
        }
}

/*------------------------------------------------------------------------*
 *      ucom_ref
 *
 * This function will increment the super UCOM reference count.
 *------------------------------------------------------------------------*/
void
ucom_ref(struct ucom_super_softc *ssc)
{
        mtx_lock(&ucom_mtx);
        ssc->sc_refs++;
        mtx_unlock(&ucom_mtx);
}

/*------------------------------------------------------------------------*
 *      ucom_free_unit
 *
 * This function will free the super UCOM's allocated unit
 * number. This function can be called on a zero-initialized
 * structure. This function can be called multiple times.
 *------------------------------------------------------------------------*/
static void
ucom_free_unit(struct ucom_super_softc *ssc)
{
        if (!(ssc->sc_flag & UCOM_FLAG_FREE_UNIT))
                return;

        ucom_unit_free(ssc->sc_unit);

        ssc->sc_flag &= ~UCOM_FLAG_FREE_UNIT;
}

/*------------------------------------------------------------------------*
 *      ucom_unref
 *
 * This function will decrement the super UCOM reference count.
 *
 * Return values:
 * 0: UCOM structures are still referenced.
 * Else: UCOM structures are no longer referenced.
 *------------------------------------------------------------------------*/
int
ucom_unref(struct ucom_super_softc *ssc)
{
        int retval;

        mtx_lock(&ucom_mtx);
        retval = (ssc->sc_refs < 2);
        ssc->sc_refs--;
        mtx_unlock(&ucom_mtx);

        if (retval)
                ucom_free_unit(ssc);

        return (retval);
}

#if defined(GDB)

#include <gdb/gdb.h>

static gdb_probe_f ucom_gdbprobe;
static gdb_init_f ucom_gdbinit;
static gdb_term_f ucom_gdbterm;
static gdb_getc_f ucom_gdbgetc;
static gdb_putc_f ucom_gdbputc;

GDB_DBGPORT(ucom, ucom_gdbprobe, ucom_gdbinit, ucom_gdbterm, ucom_gdbgetc, ucom_gdbputc);

static int
ucom_gdbprobe(void)
{
        return ((ucom_cons_softc != NULL) ? 0 : -1);
}

static void
ucom_gdbinit(void)
{
}

static void
ucom_gdbterm(void)
{
}

static void
ucom_gdbputc(int c)
{
        ucom_cnputc(NULL, c);
}

static int
ucom_gdbgetc(void)
{
        return (ucom_cngetc(NULL));
}

#endif