xen/io/xencons.c

	xencons.c revision 193974072f41a843678abf5f61979c748687e66b
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*  Copyright (c) 1990, 1991 UNIX System Laboratories, Inc. */
/*  Copyright (c) 1984, 1986, 1987, 1988, 1989, 1990 AT&T   */
/*    All Rights Reserved                   */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */


/*
 *
 * Copyright (c) 2004 Christian Limpach.
 * 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. This section intentionally left blank.
 * 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.
 */
/*
 * Section 3 of the above license was updated in response to bug 6379571.
 */

/*
 * Hypervisor virtual console driver
 */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/signal.h>
#include <sys/stream.h>
#include <sys/termio.h>
#include <sys/errno.h>
#include <sys/file.h>
#include <sys/cmn_err.h>
#include <sys/stropts.h>
#include <sys/strsubr.h>
#include <sys/strtty.h>
#include <sys/debug.h>
#include <sys/kbio.h>
#include <sys/cred.h>
#include <sys/stat.h>
#include <sys/consdev.h>
#include <sys/mkdev.h>
#include <sys/kmem.h>
#include <sys/cred.h>
#include <sys/strsun.h>
#ifdef DEBUG
#include <sys/promif.h>
#endif
#include <sys/modctl.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/sunndi.h>
#include <sys/policy.h>
#include <sys/atomic.h>
#include <sys/psm.h>
#include <xen/public/io/console.h>

#include "xencons.h"

#include <sys/hypervisor.h>
#include <sys/evtchn_impl.h>
#include <xen/sys/xenbus_impl.h>
#include <xen/sys/xendev.h>

#ifdef DEBUG
#define XENCONS_DEBUG_INIT  0x0001  /* msgs during driver initialization. */
#define XENCONS_DEBUG_INPUT 0x0002  /* characters received during int. */
#define XENCONS_DEBUG_EOT   0x0004  /* msgs when wait for xmit to finish. */
#define XENCONS_DEBUG_CLOSE 0x0008  /* msgs when driver open/close called */
#define XENCONS_DEBUG_PROCS 0x0020  /* each proc name as it is entered. */
#define XENCONS_DEBUG_OUT   0x0100  /* msgs about output events. */
#define XENCONS_DEBUG_BUSY  0x0200  /* msgs when xmit is enabled/disabled */
#define XENCONS_DEBUG_MODEM 0x0400  /* msgs about modem status & control. */
#define XENCONS_DEBUG_MODM2 0x0800  /* msgs about modem status & control. */
#define XENCONS_DEBUG_IOCTL 0x1000  /* Output msgs about ioctl messages. */
#define XENCONS_DEBUG_CHIP  0x2000  /* msgs about chip identification. */
#define XENCONS_DEBUG_SFLOW 0x4000  /* msgs when S/W flowcontrol active */
#define XENCONS_DEBUG(x) (debug & (x))
static int debug  = 0;
#else
#define XENCONS_DEBUG(x) B_FALSE
#endif

#define XENCONS_WBUFSIZE    4096

static boolean_t abort_charseq_recognize(uchar_t);

/* The async interrupt entry points */
static void xcasync_ioctl(struct asyncline *, queue_t *, mblk_t *);
static void xcasync_reioctl(void *);
static void xcasync_start(struct asyncline *);
static void xenconsputchar(cons_polledio_arg_t, uchar_t);
static int  xenconsgetchar(cons_polledio_arg_t);
static boolean_t    xenconsischar(cons_polledio_arg_t);

static uint_t   xenconsintr(caddr_t);
static uint_t   xenconsintr_priv(caddr_t);
/*PRINTFLIKE2*/
static void xenconserror(int, const char *, ...) __KPRINTFLIKE(2);
static void xencons_soft_state_free(struct xencons *);
static boolean_t
xcasync_flowcontrol_sw_input(struct xencons *, async_flowc_action, int);
static void
xcasync_flowcontrol_sw_output(struct xencons *, async_flowc_action);

void        *xencons_soft_state;
char        *xencons_wbuf;
struct xencons  *xencons_console;

static void
xenconssetup_avintr(struct xencons *xcp, int attach)
{
    /*
     * On xen, CPU 0 always exists and can't be taken offline,
     * so binding this thread to it should always succeed.
     */
    mutex_enter(&cpu_lock);
    thread_affinity_set(curthread, 0);
    mutex_exit(&cpu_lock);

    if (attach) {
        /* Setup our interrupt binding. */
        (void) add_avintr(NULL, IPL_CONS, (avfunc)xenconsintr_priv,
            "xencons", xcp->console_irq, (caddr_t)xcp, NULL, NULL,
            xcp->dip);
    } else {
        /*
         * Cleanup interrupt configuration.  Note that the framework
         * _should_ ensure that when rem_avintr() returns the interrupt
         * service routine is not currently executing and that it won't
         * be invoked again.
         */
        (void) rem_avintr(NULL, IPL_CONS, (avfunc)xenconsintr_priv,
            xcp->console_irq);
    }

    /* Notify our caller that we're done. */
    mutex_enter(&xcp->excl);
    cv_signal(&xcp->excl_cv);
    mutex_exit(&xcp->excl);

    /* Clear our binding to CPU 0 */
    thread_affinity_clear(curthread);

}

static void
xenconssetup_add_avintr(struct xencons *xcp)
{
    xenconssetup_avintr(xcp, B_TRUE);
}

static void
xenconssetup_rem_avintr(struct xencons *xcp)
{
    xenconssetup_avintr(xcp, B_FALSE);
}

static int
xenconsdetach(dev_info_t *devi, ddi_detach_cmd_t cmd)
{
    int instance;
    struct xencons *xcp;

    if (cmd != DDI_DETACH && cmd != DDI_SUSPEND)
        return (DDI_FAILURE);

    if (cmd == DDI_SUSPEND) {
        ddi_remove_intr(devi, 0, NULL);
        return (DDI_SUCCESS);
    }

    /*
     * We should never try to detach the console driver on a domU
     * because it should always be held open
     */
    ASSERT(DOMAIN_IS_INITDOMAIN(xen_info));
    if (!DOMAIN_IS_INITDOMAIN(xen_info))
        return (DDI_FAILURE);

    instance = ddi_get_instance(devi);  /* find out which unit */

    xcp = ddi_get_soft_state(xencons_soft_state, instance);
    if (xcp == NULL)
        return (DDI_FAILURE);

    /*
     * Cleanup our interrupt bindings.  For more info on why we
     * do this in a seperate thread, see the comments for when we
     * setup the interrupt bindings.
     */
    xencons_console = NULL;
    mutex_enter(&xcp->excl);
    (void) taskq_dispatch(system_taskq,
        (void (*)(void *))xenconssetup_rem_avintr, xcp, TQ_SLEEP);
    cv_wait(&xcp->excl_cv, &xcp->excl);
    mutex_exit(&xcp->excl);

    /* remove all minor device node(s) for this device */
    ddi_remove_minor_node(devi, NULL);

    /* free up state */
    xencons_soft_state_free(xcp);
    kmem_free(xencons_wbuf, XENCONS_WBUFSIZE);

    DEBUGNOTE1(XENCONS_DEBUG_INIT, "xencons%d: shutdown complete",
        instance);
    return (DDI_SUCCESS);
}

static void
xenconssetup(struct xencons *xcp)
{
    xcp->ifp = (volatile struct xencons_interface *)HYPERVISOR_console_page;

    if (DOMAIN_IS_INITDOMAIN(xen_info)) {
        xencons_wbuf = kmem_alloc(XENCONS_WBUFSIZE, KM_SLEEP);

        /*
         * Activate the xen console virq.  Note that xen requires
         * that VIRQs be bound to CPU 0 when first created.
         */
        xcp->console_irq = ec_bind_virq_to_irq(VIRQ_CONSOLE, 0);

        /*
         * Ok.  This is kinda ugly.  We want to register an
         * interrupt handler for the xen console virq, but
         * virq's are xen sepcific and currently the DDI doesn't
         * support binding to them.  So instead we need to use
         * add_avintr().  So to make things more complicated,
         * we already had to bind the xen console VIRQ to CPU 0,
         * and add_avintr() needs to be invoked on the same CPU
         * where the VIRQ is bound, in this case on CPU 0.  We
         * could just temporarily bind ourselves to CPU 0, but
         * we don't want to do that since this attach thread
         * could have been invoked in a user thread context,
         * in which case this thread could already have some
         * pre-existing cpu binding.  So to avoid changing our
         * cpu binding we're going to use a taskq thread that
         * will bind to CPU 0 and register our interrupts
         * handler for us.
         */
        mutex_enter(&xcp->excl);
        (void) taskq_dispatch(system_taskq,
            (void (*)(void *))xenconssetup_add_avintr, xcp, TQ_SLEEP);
        cv_wait(&xcp->excl_cv, &xcp->excl);
        mutex_exit(&xcp->excl);
    } else {
        (void) xvdi_alloc_evtchn(xcp->dip);
        xcp->evtchn = xvdi_get_evtchn(xcp->dip);
        (void) ddi_add_intr(xcp->dip, 0, NULL, NULL, xenconsintr,
            (caddr_t)xcp);
    }
}

static int
xenconsattach(dev_info_t *devi, ddi_attach_cmd_t cmd)
{
    int instance = ddi_get_instance(devi);
    struct xencons *xcp;
    int ret;

    /* There can be only one. */
    if (instance != 0)
        return (DDI_FAILURE);

    switch (cmd) {
    case DDI_RESUME:
        xcp = xencons_console;
        xenconssetup(xcp);
        return (DDI_SUCCESS);
    case DDI_ATTACH:
        break;
    default:
        return (DDI_FAILURE);
    }

    ret = ddi_soft_state_zalloc(xencons_soft_state, instance);
    if (ret != DDI_SUCCESS)
        return (DDI_FAILURE);
    xcp = ddi_get_soft_state(xencons_soft_state, instance);
    ASSERT(xcp != NULL);    /* can't fail - we only just allocated it */

    /*
     * Set up the other components of the xencons structure for this port.
     */
    xcp->unit = instance;
    xcp->dip = devi;

    /* Fill in the polled I/O structure. */
    xcp->polledio.cons_polledio_version = CONSPOLLEDIO_V0;
    xcp->polledio.cons_polledio_argument = (cons_polledio_arg_t)xcp;
    xcp->polledio.cons_polledio_putchar = xenconsputchar;
    xcp->polledio.cons_polledio_getchar = xenconsgetchar;
    xcp->polledio.cons_polledio_ischar = xenconsischar;
    xcp->polledio.cons_polledio_enter = NULL;
    xcp->polledio.cons_polledio_exit = NULL;

    /*
     * Initializes the asyncline structure which has TTY protocol-private
     * data before enabling interrupts.
     */
    xcp->priv = kmem_zalloc(sizeof (struct asyncline), KM_SLEEP);
    xcp->priv->async_common = xcp;
    cv_init(&xcp->priv->async_flags_cv, NULL, CV_DRIVER, NULL);

    /* Initialize mutexes before accessing the interface. */
    mutex_init(&xcp->excl, NULL, MUTEX_DRIVER, NULL);
    cv_init(&xcp->excl_cv, NULL, CV_DEFAULT, NULL);

    /* create minor device node for this device */
    ret = ddi_create_minor_node(devi, "xencons", S_IFCHR, instance,
        DDI_NT_SERIAL, NULL);
    if (ret != DDI_SUCCESS) {
        ddi_remove_minor_node(devi, NULL);
        xencons_soft_state_free(xcp);
        return (DDI_FAILURE);
    }

    ddi_report_dev(devi);
    xencons_console = xcp;
    xenconssetup(xcp);
    DEBUGCONT1(XENCONS_DEBUG_INIT, "xencons%dattach: done\n", instance);
    return (DDI_SUCCESS);
}

/*ARGSUSED*/
static int
xenconsinfo(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg,
    void **result)
{
    dev_t dev = (dev_t)arg;
    int instance, error;
    struct xencons *xcp;

    instance = getminor(dev);
    xcp = ddi_get_soft_state(xencons_soft_state, instance);
    if (xcp == NULL)
        return (DDI_FAILURE);

    switch (infocmd) {
    case DDI_INFO_DEVT2DEVINFO:
        if (xcp->dip == NULL)
            error = DDI_FAILURE;
        else {
            *result = (void *) xcp->dip;
            error = DDI_SUCCESS;
        }
        break;
    case DDI_INFO_DEVT2INSTANCE:
        *result = (void *)(intptr_t)instance;
        error = DDI_SUCCESS;
        break;
    default:
        error = DDI_FAILURE;
    }
    return (error);
}

/* xencons_soft_state_free - local wrapper for ddi_soft_state_free(9F) */

static void
xencons_soft_state_free(struct xencons *xcp)
{
    mutex_destroy(&xcp->excl);
    cv_destroy(&xcp->excl_cv);
    kmem_free(xcp->priv, sizeof (struct asyncline));
    ddi_soft_state_free(xencons_soft_state, xcp->unit);
}

/*ARGSUSED*/
static int
xenconsopen(queue_t *rq, dev_t *dev, int flag, int sflag, cred_t *cr)
{
    struct xencons  *xcp;
    struct asyncline *async;
    int     unit;

    unit = getminor(*dev);
    DEBUGCONT1(XENCONS_DEBUG_CLOSE, "xencons%dopen\n", unit);
    xcp = ddi_get_soft_state(xencons_soft_state, unit);
    if (xcp == NULL)
        return (ENXIO);     /* unit not configured */
    async = xcp->priv;
    mutex_enter(&xcp->excl);

again:

    if ((async->async_flags & ASYNC_ISOPEN) == 0) {
        async->async_ttycommon.t_iflag = 0;
        async->async_ttycommon.t_iocpending = NULL;
        async->async_ttycommon.t_size.ws_row = 0;
        async->async_ttycommon.t_size.ws_col = 0;
        async->async_ttycommon.t_size.ws_xpixel = 0;
        async->async_ttycommon.t_size.ws_ypixel = 0;
        async->async_dev = *dev;
        async->async_wbufcid = 0;

        async->async_startc = CSTART;
        async->async_stopc = CSTOP;
    } else if ((async->async_ttycommon.t_flags & TS_XCLUDE) &&
        secpolicy_excl_open(cr) != 0) {
        mutex_exit(&xcp->excl);
        return (EBUSY);
    }

    async->async_ttycommon.t_flags |= TS_SOFTCAR;

    async->async_ttycommon.t_readq = rq;
    async->async_ttycommon.t_writeq = WR(rq);
    rq->q_ptr = WR(rq)->q_ptr = (caddr_t)async;
    mutex_exit(&xcp->excl);
    /*
     * Caution here -- qprocson sets the pointers that are used by canput
     * called by xencons_rxint.  ASYNC_ISOPEN must *not* be set until those
     * pointers are valid.
     */
    qprocson(rq);
    async->async_flags |= ASYNC_ISOPEN;
    DEBUGCONT1(XENCONS_DEBUG_INIT, "asy%dopen: done\n", unit);
    return (0);
}


/*
 * Close routine.
 */
/*ARGSUSED*/
static int
xenconsclose(queue_t *q, int flag, cred_t *credp)
{
    struct asyncline *async;
    struct xencons   *xcp;
#ifdef DEBUG
    int instance;
#endif

    async = (struct asyncline *)q->q_ptr;
    ASSERT(async != NULL);
    xcp = async->async_common;
#ifdef DEBUG
    instance = xcp->unit;
    DEBUGCONT1(XENCONS_DEBUG_CLOSE, "xencons%dclose\n", instance);
#endif

    mutex_enter(&xcp->excl);
    async->async_flags |= ASYNC_CLOSING;

    async->async_ocnt = 0;
    if (async->async_xmitblk != NULL)
        freeb(async->async_xmitblk);
    async->async_xmitblk = NULL;

out:
    ttycommon_close(&async->async_ttycommon);

    /*
     * Cancel outstanding "bufcall" request.
     */
    if (async->async_wbufcid != 0) {
        unbufcall(async->async_wbufcid);
        async->async_wbufcid = 0;
    }

    /* Note that qprocsoff can't be done until after interrupts are off */
    qprocsoff(q);
    q->q_ptr = WR(q)->q_ptr = NULL;
    async->async_ttycommon.t_readq = NULL;
    async->async_ttycommon.t_writeq = NULL;

    /*
     * Clear out device state, except persistant device property flags.
     */
    async->async_flags = 0;
    cv_broadcast(&async->async_flags_cv);
    mutex_exit(&xcp->excl);

    DEBUGCONT1(XENCONS_DEBUG_CLOSE, "xencons%dclose: done\n", instance);
    return (0);
}

#define INBUF_IX(ix, ifp)   (DOMAIN_IS_INITDOMAIN(xen_info) ? \
    (ix) : MASK_XENCONS_IDX((ix), (ifp)->in))

/*
 * Handle a xen console rx interrupt.
 */
/*ARGSUSED*/
static void
xencons_rxint(struct xencons *xcp)
{
    struct asyncline *async;
    short   cc;
    mblk_t  *bp;
    queue_t *q;
    uchar_t c, buf[16];
    uchar_t *cp;
    tty_common_t    *tp;
    int instance;
    volatile struct xencons_interface *ifp;
    XENCONS_RING_IDX cons, prod;

    DEBUGCONT0(XENCONS_DEBUG_PROCS, "xencons_rxint\n");

loop:
    mutex_enter(&xcp->excl);

    /* sanity check if we should bail */
    if (xencons_console == NULL) {
        mutex_exit(&xcp->excl);
        goto out;
    }

    async = xcp->priv;
    instance = xcp->unit;
    ifp = xcp->ifp;
    tp = &async->async_ttycommon;
    q = tp->t_readq;

    if (async->async_flags & ASYNC_OUT_FLW_RESUME) {
        xcasync_start(async);
        async->async_flags &= ~ASYNC_OUT_FLW_RESUME;
    }

    /*
     * If data is available, send it up the stream if there's
     * somebody listening.
     */
    if (!(async->async_flags & ASYNC_ISOPEN)) {
        mutex_exit(&xcp->excl);
        goto out;
    }
    if (DOMAIN_IS_INITDOMAIN(xen_info)) {
        cc = HYPERVISOR_console_io(CONSOLEIO_read, 16, (char *)buf);
        cp = buf;
        cons = 0;
    } else {
        cons = ifp->in_cons;
        prod = ifp->in_prod;

        cc = prod - cons;
        cp = (uchar_t *)ifp->in;
    }
    if (cc <= 0) {
        mutex_exit(&xcp->excl);
        goto out;
    }

    /*
     * Check for character break sequence.
     *
     * Note that normally asy drivers only check for a character sequence
     * if abort_enable == KIOCABORTALTERNATE and otherwise use a break
     * sensed on the line to do an abort_sequence_enter.  Since the
     * hypervisor does not use a real chip for the console we default to
     * using the alternate sequence.
     */
    if ((abort_enable == KIOCABORTENABLE) && (xcp->flags & ASY_CONSOLE)) {
        XENCONS_RING_IDX i;

        for (i = 0; i < cc; i++) {
            c = cp[INBUF_IX(cons + i, ifp)];
            if (abort_charseq_recognize(c)) {
                /*
                 * Eat abort seg, it's not a valid debugger
                 * command.
                 */
                if (!DOMAIN_IS_INITDOMAIN(xen_info)) {
                    membar_producer();
                    ifp->in_cons = cons + i;
                } else {
                    cons += i;
                }
                abort_sequence_enter((char *)NULL);
                /*
                 * Back from debugger, resume normal processing
                 */
                mutex_exit(&xcp->excl);
                goto loop;
            }
        }
    }

    if (!canput(q)) {
        if (!(async->async_inflow_source & IN_FLOW_STREAMS)) {
            (void) xcasync_flowcontrol_sw_input(xcp, FLOW_STOP,
                IN_FLOW_STREAMS);
        }
        mutex_exit(&xcp->excl);
        goto out;
    }
    if (async->async_inflow_source & IN_FLOW_STREAMS) {
        (void) xcasync_flowcontrol_sw_input(xcp, FLOW_START,
            IN_FLOW_STREAMS);
    }
    DEBUGCONT2(XENCONS_DEBUG_INPUT,
        "xencons%d_rxint: %d char(s) in queue.\n", instance, cc);
    if (!(bp = allocb(cc, BPRI_MED))) {
        mutex_exit(&xcp->excl);
        ttycommon_qfull(&async->async_ttycommon, q);
        goto out;
    }
    do {
        c = cp[INBUF_IX(cons++, ifp)];
        /*
         * We handle XON/XOFF char if IXON is set,
         * but if received char is _POSIX_VDISABLE,
         * we left it to the up level module.
         */
        if (tp->t_iflag & IXON) {
            if ((c == async->async_stopc) &&
                (c != _POSIX_VDISABLE)) {
                xcasync_flowcontrol_sw_output(xcp, FLOW_STOP);
                continue;
            } else if ((c == async->async_startc) &&
                (c != _POSIX_VDISABLE)) {
                xcasync_flowcontrol_sw_output(xcp, FLOW_START);
                continue;
            }
            if ((tp->t_iflag & IXANY) &&
                (async->async_flags & ASYNC_SW_OUT_FLW)) {
                xcasync_flowcontrol_sw_output(xcp, FLOW_START);
            }
        }
        *bp->b_wptr++ = c;
    } while (--cc);
    membar_producer();
    if (!DOMAIN_IS_INITDOMAIN(xen_info))
        ifp->in_cons = cons;
    mutex_exit(&xcp->excl);
    if (bp->b_wptr > bp->b_rptr) {
        if (!canput(q)) {
            xenconserror(CE_NOTE, "xencons%d: local queue full",
                instance);
            freemsg(bp);
        } else
            (void) putq(q, bp);
    } else
        freemsg(bp);
    if (DOMAIN_IS_INITDOMAIN(xen_info))
        goto loop;
out:
    DEBUGCONT1(XENCONS_DEBUG_PROCS, "xencons%d_rxint: done\n", instance);
    if (!DOMAIN_IS_INITDOMAIN(xen_info))
        ec_notify_via_evtchn(xcp->evtchn);
}


/*
 * Handle a xen console tx interrupt.
 */
/*ARGSUSED*/
static void
xencons_txint(struct xencons *xcp)
{
    struct asyncline *async;

    DEBUGCONT0(XENCONS_DEBUG_PROCS, "xencons_txint\n");

    /*
     * prevent recursive entry
     */
    if (mutex_owner(&xcp->excl) == curthread) {
        goto out;
    }

    mutex_enter(&xcp->excl);
    if (xencons_console == NULL) {
        mutex_exit(&xcp->excl);
        goto out;
    }

    /* make sure the device is open */
    async = xcp->priv;
    if ((async->async_flags & ASYNC_ISOPEN) != 0)
        xcasync_start(async);

    mutex_exit(&xcp->excl);
out:
    DEBUGCONT0(XENCONS_DEBUG_PROCS, "xencons_txint: done\n");
}


/*
 * Get an event when input ring becomes not empty or output ring becomes not
 * full.
 */
static uint_t
xenconsintr(caddr_t arg)
{
    struct xencons *xcp = (struct xencons *)arg;
    volatile struct xencons_interface *ifp = xcp->ifp;

    if (ifp->in_prod != ifp->in_cons)
        xencons_rxint(xcp);
    if (ifp->out_prod - ifp->out_cons < sizeof (ifp->out))
        xencons_txint(xcp);
    return (DDI_INTR_CLAIMED);
}

/*
 * Console interrupt routine for priviliged domains
 */
static uint_t
xenconsintr_priv(caddr_t arg)
{
    struct xencons *xcp = (struct xencons *)arg;

    xencons_rxint(xcp);
    xencons_txint(xcp);
    return (DDI_INTR_CLAIMED);
}

/*
 * Start output on a line, unless it's busy, frozen, or otherwise.
 */
/*ARGSUSED*/
static void
xcasync_start(struct asyncline *async)
{
    struct xencons *xcp = async->async_common;
    int cc;
    queue_t *q;
    mblk_t *bp;
    int len, space, blen;
    mblk_t *nbp;

#ifdef DEBUG
    int instance = xcp->unit;

    DEBUGCONT1(XENCONS_DEBUG_PROCS, "async%d_nstart\n", instance);
#endif
    ASSERT(mutex_owned(&xcp->excl));

    /*
     * Check only pended sw input flow control.
     */
domore:
    (void) xcasync_flowcontrol_sw_input(xcp, FLOW_CHECK, IN_FLOW_NULL);

    if ((q = async->async_ttycommon.t_writeq) == NULL) {
        return; /* not attached to a stream */
    }

    for (;;) {
        if ((bp = getq(q)) == NULL)
            return; /* no data to transmit */

        /*
         * We have a message block to work on.
         * Check whether it's a break, a delay, or an ioctl (the latter
         * occurs if the ioctl in question was waiting for the output
         * to drain).  If it's one of those, process it immediately.
         */
        switch (bp->b_datap->db_type) {

        case M_IOCTL:
            /*
             * This ioctl was waiting for the output ahead of
             * it to drain; obviously, it has.  Do it, and
             * then grab the next message after it.
             */
            mutex_exit(&xcp->excl);
            xcasync_ioctl(async, q, bp);
            mutex_enter(&xcp->excl);
            continue;
        }

        while (bp != NULL && (cc = bp->b_wptr - bp->b_rptr) == 0) {
            nbp = bp->b_cont;
            freeb(bp);
            bp = nbp;
        }
        if (bp != NULL)
            break;
    }

    /*
     * We have data to transmit.  If output is stopped, put
     * it back and try again later.
     */
    if (async->async_flags & (ASYNC_SW_OUT_FLW | ASYNC_STOPPED)) {
        (void) putbq(q, bp);
        return;
    }


    if (DOMAIN_IS_INITDOMAIN(xen_info)) {
        len = 0;
        space = XENCONS_WBUFSIZE;
        while (bp != NULL && space) {
            blen = bp->b_wptr - bp->b_rptr;
            cc = min(blen, space);
            bcopy(bp->b_rptr, &xencons_wbuf[len], cc);
            bp->b_rptr += cc;
            if (cc == blen) {
                nbp = bp->b_cont;
                freeb(bp);
                bp = nbp;
            }
            space -= cc;
            len += cc;
        }
        mutex_exit(&xcp->excl);
        (void) HYPERVISOR_console_io(CONSOLEIO_write, len,
            xencons_wbuf);
        mutex_enter(&xcp->excl);
        if (bp != NULL)
            (void) putbq(q, bp); /* not done with this msg yet */
        /*
         * There are no completion interrupts when using the
         * HYPERVISOR_console_io call to write console data
         * so we loop here till we have sent all the data to the
         * hypervisor.
         */
        goto domore;
    } else {
        volatile struct xencons_interface *ifp = xcp->ifp;
        XENCONS_RING_IDX cons, prod;

        cons = ifp->out_cons;
        prod = ifp->out_prod;
        membar_enter();
        while (bp != NULL && ((prod - cons) < sizeof (ifp->out))) {
            ifp->out[MASK_XENCONS_IDX(prod++, ifp->out)] =
                *bp->b_rptr++;
            if (bp->b_rptr == bp->b_wptr) {
                nbp = bp->b_cont;
                freeb(bp);
                bp = nbp;
            }
        }
        membar_producer();
        ifp->out_prod = prod;
        ec_notify_via_evtchn(xcp->evtchn);
        if (bp != NULL)
            (void) putbq(q, bp); /* not done with this msg yet */
    }
}


/*
 * Process an "ioctl" message sent down to us.
 * Note that we don't need to get any locks until we are ready to access
 * the hardware.  Nothing we access until then is going to be altered
 * outside of the STREAMS framework, so we should be safe.
 */
static void
xcasync_ioctl(struct asyncline *async, queue_t *wq, mblk_t *mp)
{
    struct xencons *xcp = async->async_common;
    tty_common_t  *tp = &async->async_ttycommon;
    struct iocblk *iocp;
    unsigned datasize;
    int error = 0;

#ifdef DEBUG
    int instance = xcp->unit;

    DEBUGCONT1(XENCONS_DEBUG_PROCS, "async%d_ioctl\n", instance);
#endif

    if (tp->t_iocpending != NULL) {
        /*
         * We were holding an "ioctl" response pending the
         * availability of an "mblk" to hold data to be passed up;
         * another "ioctl" came through, which means that "ioctl"
         * must have timed out or been aborted.
         */
        freemsg(async->async_ttycommon.t_iocpending);
        async->async_ttycommon.t_iocpending = NULL;
    }

    iocp = (struct iocblk *)mp->b_rptr;

    /*
     * For TIOCMGET and the PPS ioctls, do NOT call ttycommon_ioctl()
     * because this function frees up the message block (mp->b_cont) that
     * contains the user location where we pass back the results.
     *
     * Similarly, CONSOPENPOLLEDIO needs ioc_count, which ttycommon_ioctl
     * zaps.  We know that ttycommon_ioctl doesn't know any CONS*
     * ioctls, so keep the others safe too.
     */
    DEBUGCONT2(XENCONS_DEBUG_IOCTL, "async%d_ioctl: %s\n",
        instance,
        iocp->ioc_cmd == TIOCMGET ? "TIOCMGET" :
        iocp->ioc_cmd == TIOCMSET ? "TIOCMSET" :
        iocp->ioc_cmd == TIOCMBIS ? "TIOCMBIS" :
        iocp->ioc_cmd == TIOCMBIC ? "TIOCMBIC" : "other");

    switch (iocp->ioc_cmd) {
    case TIOCMGET:
    case TIOCGPPS:
    case TIOCSPPS:
    case TIOCGPPSEV:
    case CONSOPENPOLLEDIO:
    case CONSCLOSEPOLLEDIO:
    case CONSSETABORTENABLE:
    case CONSGETABORTENABLE:
        error = -1; /* Do Nothing */
        break;
    default:

        /*
         * The only way in which "ttycommon_ioctl" can fail is if the
         * "ioctl" requires a response containing data to be returned
         * to the user, and no mblk could be allocated for the data.
         * No such "ioctl" alters our state.  Thus, we always go ahead
         * and do any state-changes the "ioctl" calls for.  If we
         * couldn't allocate the data, "ttycommon_ioctl" has stashed
         * the "ioctl" away safely, so we just call "bufcall" to
         * request that we be called back when we stand a better
         * chance of allocating the data.
         */
        if ((datasize = ttycommon_ioctl(tp, wq, mp, &error)) != 0) {
            if (async->async_wbufcid)
                unbufcall(async->async_wbufcid);
            async->async_wbufcid = bufcall(datasize, BPRI_HI,
                (void (*)(void *)) xcasync_reioctl,
                (void *)(intptr_t)async->async_common->unit);
            return;
        }
    }

    mutex_enter(&xcp->excl);

    if (error == 0) {
        /*
         * "ttycommon_ioctl" did most of the work; we just use the
         * data it set up.
         */
        switch (iocp->ioc_cmd) {

        case TCSETS:
        case TCSETSF:
        case TCSETSW:
        case TCSETA:
        case TCSETAW:
        case TCSETAF:
            break;
        }
    } else if (error < 0) {
        /*
         * "ttycommon_ioctl" didn't do anything; we process it here.
         */
        error = 0;
        switch (iocp->ioc_cmd) {

        case TCSBRK:
            error = miocpullup(mp, sizeof (int));
            break;

        case TIOCSBRK:
            mioc2ack(mp, NULL, 0, 0);
            break;

        case TIOCCBRK:
            mioc2ack(mp, NULL, 0, 0);
            break;

        case CONSOPENPOLLEDIO:
            error = miocpullup(mp, sizeof (cons_polledio_arg_t));
            if (error != 0)
                break;

            *(cons_polledio_arg_t *)mp->b_cont->b_rptr =
                (cons_polledio_arg_t)&xcp->polledio;

            mp->b_datap->db_type = M_IOCACK;
            break;

        case CONSCLOSEPOLLEDIO:
            mp->b_datap->db_type = M_IOCACK;
            iocp->ioc_error = 0;
            iocp->ioc_rval = 0;
            break;

        case CONSSETABORTENABLE:
            error = secpolicy_console(iocp->ioc_cr);
            if (error != 0)
                break;

            if (iocp->ioc_count != TRANSPARENT) {
                error = EINVAL;
                break;
            }

            if (*(intptr_t *)mp->b_cont->b_rptr)
                xcp->flags |= ASY_CONSOLE;
            else
                xcp->flags &= ~ASY_CONSOLE;

            mp->b_datap->db_type = M_IOCACK;
            iocp->ioc_error = 0;
            iocp->ioc_rval = 0;
            break;

        case CONSGETABORTENABLE:
            /*CONSTANTCONDITION*/
            ASSERT(sizeof (boolean_t) <= sizeof (boolean_t *));
            /*
             * Store the return value right in the payload
             * we were passed.  Crude.
             */
            mcopyout(mp, NULL, sizeof (boolean_t), NULL, NULL);
            *(boolean_t *)mp->b_cont->b_rptr =
                (xcp->flags & ASY_CONSOLE) != 0;
            break;

        default:
            /*
             * If we don't understand it, it's an error.  NAK it.
             */
            error = EINVAL;
            break;
        }
    }
    if (error != 0) {
        iocp->ioc_error = error;
        mp->b_datap->db_type = M_IOCNAK;
    }
    mutex_exit(&xcp->excl);
    qreply(wq, mp);
    DEBUGCONT1(XENCONS_DEBUG_PROCS, "async%d_ioctl: done\n", instance);
}

static int
xenconsrsrv(queue_t *q)
{
    mblk_t *bp;

    while (canputnext(q) && (bp = getq(q)))
        putnext(q, bp);
    return (0);
}

/*
 * Put procedure for write queue.
 * Respond to M_STOP, M_START, M_IOCTL, and M_FLUSH messages here;
 * set the flow control character for M_STOPI and M_STARTI messages;
 * queue up M_BREAK, M_DELAY, and M_DATA messages for processing
 * by the start routine, and then call the start routine; discard
 * everything else.  Note that this driver does not incorporate any
 * mechanism to negotiate to handle the canonicalization process.
 * It expects that these functions are handled in upper module(s),
 * as we do in ldterm.
 */
static int
xenconswput(queue_t *q, mblk_t *mp)
{
    struct asyncline *async;
    struct xencons *xcp;

    async = (struct asyncline *)q->q_ptr;
    xcp = async->async_common;

    switch (mp->b_datap->db_type) {

    case M_STOP:
        mutex_enter(&xcp->excl);
        async->async_flags |= ASYNC_STOPPED;
        mutex_exit(&xcp->excl);
        freemsg(mp);
        break;

    case M_START:
        mutex_enter(&xcp->excl);
        if (async->async_flags & ASYNC_STOPPED) {
            async->async_flags &= ~ASYNC_STOPPED;
            xcasync_start(async);
        }
        mutex_exit(&xcp->excl);
        freemsg(mp);
        break;

    case M_IOCTL:
        switch (((struct iocblk *)mp->b_rptr)->ioc_cmd) {

        case TCSETSW:
        case TCSETSF:
        case TCSETAW:
        case TCSETAF:
            /*
             * The changes do not take effect until all
             * output queued before them is drained.
             * Put this message on the queue, so that
             * "xcasync_start" will see it when it's done
             * with the output before it.  Poke the
             * start routine, just in case.
             */
            (void) putq(q, mp);
            mutex_enter(&xcp->excl);
            xcasync_start(async);
            mutex_exit(&xcp->excl);
            break;

        default:
            /*
             * Do it now.
             */
            xcasync_ioctl(async, q, mp);
            break;
        }
        break;

    case M_FLUSH:
        if (*mp->b_rptr & FLUSHW) {
            mutex_enter(&xcp->excl);
            /*
             * Flush our write queue.
             */
            flushq(q, FLUSHDATA);   /* XXX doesn't flush M_DELAY */
            if (async->async_xmitblk != NULL) {
                freeb(async->async_xmitblk);
                async->async_xmitblk = NULL;
            }
            mutex_exit(&xcp->excl);
            *mp->b_rptr &= ~FLUSHW; /* it has been flushed */
        }
        if (*mp->b_rptr & FLUSHR) {
            flushq(RD(q), FLUSHDATA);
            qreply(q, mp);  /* give the read queues a crack at it */
        } else {
            freemsg(mp);
        }

        /*
         * We must make sure we process messages that survive the
         * write-side flush.
         */
        mutex_enter(&xcp->excl);
        xcasync_start(async);
        mutex_exit(&xcp->excl);
        break;

    case M_BREAK:
    case M_DELAY:
    case M_DATA:
        /*
         * Queue the message up to be transmitted,
         * and poke the start routine.
         */
        (void) putq(q, mp);
        mutex_enter(&xcp->excl);
        xcasync_start(async);
        mutex_exit(&xcp->excl);
        break;

    case M_STOPI:
        mutex_enter(&xcp->excl);
        mutex_enter(&xcp->excl);
        if (!(async->async_inflow_source & IN_FLOW_USER)) {
            (void) xcasync_flowcontrol_sw_input(xcp, FLOW_STOP,
                IN_FLOW_USER);
        }
        mutex_exit(&xcp->excl);
        mutex_exit(&xcp->excl);
        freemsg(mp);
        break;

    case M_STARTI:
        mutex_enter(&xcp->excl);
        mutex_enter(&xcp->excl);
        if (async->async_inflow_source & IN_FLOW_USER) {
            (void) xcasync_flowcontrol_sw_input(xcp, FLOW_START,
                IN_FLOW_USER);
        }
        mutex_exit(&xcp->excl);
        mutex_exit(&xcp->excl);
        freemsg(mp);
        break;

    case M_CTL:
        if (MBLKL(mp) >= sizeof (struct iocblk) &&
            ((struct iocblk *)mp->b_rptr)->ioc_cmd == MC_POSIXQUERY) {
            ((struct iocblk *)mp->b_rptr)->ioc_cmd = MC_HAS_POSIX;
            qreply(q, mp);
        } else {
            freemsg(mp);
        }
        break;

    default:
        freemsg(mp);
        break;
    }
    return (0);
}

/*
 * Retry an "ioctl", now that "bufcall" claims we may be able to allocate
 * the buffer we need.
 */
static void
xcasync_reioctl(void *unit)
{
    int instance = (uintptr_t)unit;
    struct asyncline *async;
    struct xencons *xcp;
    queue_t *q;
    mblk_t  *mp;

    xcp = ddi_get_soft_state(xencons_soft_state, instance);
    ASSERT(xcp != NULL);
    async = xcp->priv;

    /*
     * The bufcall is no longer pending.
     */
    mutex_enter(&xcp->excl);
    async->async_wbufcid = 0;
    if ((q = async->async_ttycommon.t_writeq) == NULL) {
        mutex_exit(&xcp->excl);
        return;
    }
    if ((mp = async->async_ttycommon.t_iocpending) != NULL) {
        /* not pending any more */
        async->async_ttycommon.t_iocpending = NULL;
        mutex_exit(&xcp->excl);
        xcasync_ioctl(async, q, mp);
    } else
        mutex_exit(&xcp->excl);
}


/*
 * debugger/console support routines.
 */

/*
 * put a character out
 * Do not use interrupts.  If char is LF, put out CR, LF.
 */
/*ARGSUSED*/
static void
xenconsputchar(cons_polledio_arg_t arg, uchar_t c)
{
    struct xencons *xcp = xencons_console;
    volatile struct xencons_interface *ifp = xcp->ifp;
    XENCONS_RING_IDX prod;

    if (c == '\n')
        xenconsputchar(arg, '\r');

    /*
     * domain 0 can use the console I/O...
     */
    if (DOMAIN_IS_INITDOMAIN(xen_info)) {
        char    buffer[1];

        buffer[0] = c;
        (void) HYPERVISOR_console_io(CONSOLEIO_write, 1, buffer);
        return;
    }

    /*
     * domU has to go through dom0 virtual console.
     */
    while (ifp->out_prod - ifp->out_cons == sizeof (ifp->out))
        (void) HYPERVISOR_yield();

    prod = ifp->out_prod;
    ifp->out[MASK_XENCONS_IDX(prod++, ifp->out)] = c;
    membar_producer();
    ifp->out_prod = prod;
    ec_notify_via_evtchn(xcp->evtchn);
}

/*
 * See if there's a character available. If no character is
 * available, return 0. Run in polled mode, no interrupts.
 */
static boolean_t
xenconsischar(cons_polledio_arg_t arg)
{
    struct xencons *xcp = (struct xencons *)arg;
    volatile struct xencons_interface *ifp = xcp->ifp;

    if (xcp->polldix < xcp->polllen)
        return (B_TRUE);
    /*
     * domain 0 can use the console I/O...
     */
    xcp->polldix = 0;
    xcp->polllen = 0;
    if (DOMAIN_IS_INITDOMAIN(xen_info)) {
        xcp->polllen = HYPERVISOR_console_io(CONSOLEIO_read, 1,
            (char *)xcp->pollbuf);
        return (xcp->polllen != 0);
    }

    /*
     * domU has to go through virtual console device.
     */
    if (ifp->in_prod != ifp->in_cons) {
        XENCONS_RING_IDX cons;

        cons = ifp->in_cons;
        membar_enter();
        xcp->pollbuf[0] = ifp->in[MASK_XENCONS_IDX(cons++, ifp->in)];
        membar_producer();
        ifp->in_cons = cons;
        xcp->polllen = 1;
    }
    return (xcp->polllen != 0);
}

/*
 * Get a character. Run in polled mode, no interrupts.
 */
static int
xenconsgetchar(cons_polledio_arg_t arg)
{
    struct xencons *xcp = (struct xencons *)arg;

    ec_wait_on_evtchn(xcp->evtchn, (int (*)(void *))xenconsischar, arg);

    return (xcp->pollbuf[xcp->polldix++]);
}

static void
xenconserror(int level, const char *fmt, ...)
{
    va_list adx;
    static time_t   last;
    static const char *lastfmt;
    time_t now;

    /*
     * Don't print the same error message too often.
     * Print the message only if we have not printed the
     * message within the last second.
     * Note: that fmt cannot be a pointer to a string
     * stored on the stack. The fmt pointer
     * must be in the data segment otherwise lastfmt would point
     * to non-sense.
     */
    now = gethrestime_sec();
    if (last == now && lastfmt == fmt)
        return;

    last = now;
    lastfmt = fmt;

    va_start(adx, fmt);
    vcmn_err(level, fmt, adx);
    va_end(adx);
}


/*
 * Check for abort character sequence
 */
static boolean_t
abort_charseq_recognize(uchar_t ch)
{
    static int state = 0;
#define CNTRL(c) ((c)&037)
    static char sequence[] = { '\r', '~', CNTRL('b') };

    if (ch == sequence[state]) {
        if (++state >= sizeof (sequence)) {
            state = 0;
            return (B_TRUE);
        }
    } else {
        state = (ch == sequence[0]) ? 1 : 0;
    }
    return (B_FALSE);
}

/*
 * Flow control functions
 */

/*
 * Software output flow control
 * This function can be executed sucessfully at any situation.
 * It does not handle HW, and just change the SW output flow control flag.
 * INPUT VALUE of onoff:
 *                 FLOW_START means to clear SW output flow control flag,
 *          also set ASYNC_OUT_FLW_RESUME.
 *                 FLOW_STOP means to set SW output flow control flag,
 *          also clear ASYNC_OUT_FLW_RESUME.
 */
static void
xcasync_flowcontrol_sw_output(struct xencons *xcp, async_flowc_action onoff)
{
    struct asyncline *async = xcp->priv;
    int instance = xcp->unit;

    ASSERT(mutex_owned(&xcp->excl));

    if (!(async->async_ttycommon.t_iflag & IXON))
        return;

    switch (onoff) {
    case FLOW_STOP:
        async->async_flags |= ASYNC_SW_OUT_FLW;
        async->async_flags &= ~ASYNC_OUT_FLW_RESUME;
        DEBUGCONT1(XENCONS_DEBUG_SFLOW,
            "xencons%d: output sflow stop\n", instance);
        break;
    case FLOW_START:
        async->async_flags &= ~ASYNC_SW_OUT_FLW;
        async->async_flags |= ASYNC_OUT_FLW_RESUME;
        DEBUGCONT1(XENCONS_DEBUG_SFLOW,
            "xencons%d: output sflow start\n", instance);
        break;
    default:
        break;
    }
}

/*
 * Software input flow control
 * This function can execute software input flow control
 * INPUT VALUE of onoff:
 *               FLOW_START means to send out a XON char
 *                          and clear SW input flow control flag.
 *               FLOW_STOP means to send out a XOFF char
 *                          and set SW input flow control flag.
 *               FLOW_CHECK means to check whether there is pending XON/XOFF
 *                          if it is true, send it out.
 * INPUT VALUE of type:
 *       IN_FLOW_STREAMS means flow control is due to STREAMS
 *       IN_FLOW_USER means flow control is due to user's commands
 * RETURN VALUE: B_FALSE means no flow control char is sent
 *               B_TRUE means one flow control char is sent
 */
static boolean_t
xcasync_flowcontrol_sw_input(struct xencons *xcp, async_flowc_action onoff,
    int type)
{
    struct asyncline *async = xcp->priv;
    int instance = xcp->unit;
    int rval = B_FALSE;

    ASSERT(mutex_owned(&xcp->excl));

    if (!(async->async_ttycommon.t_iflag & IXOFF))
        return (rval);

    /*
     * If we get this far, then we know IXOFF is set.
     */
    switch (onoff) {
    case FLOW_STOP:
        async->async_inflow_source |= type;

        /*
         * We'll send an XOFF character for each of up to
         * three different input flow control attempts to stop input.
         * If we already send out one XOFF, but FLOW_STOP comes again,
         * it seems that input flow control becomes more serious,
         * then send XOFF again.
         */
        if (async->async_inflow_source & (IN_FLOW_STREAMS |
            IN_FLOW_USER))
            async->async_flags |= ASYNC_SW_IN_FLOW |
                ASYNC_SW_IN_NEEDED;
        DEBUGCONT2(XENCONS_DEBUG_SFLOW, "xencons%d: input sflow stop, "
            "type = %x\n", instance, async->async_inflow_source);
        break;
    case FLOW_START:
        async->async_inflow_source &= ~type;
        if (async->async_inflow_source == 0) {
            async->async_flags = (async->async_flags &
                ~ASYNC_SW_IN_FLOW) | ASYNC_SW_IN_NEEDED;
            DEBUGCONT1(XENCONS_DEBUG_SFLOW, "xencons%d: "
                "input sflow start\n", instance);
        }
        break;
    default:
        break;
    }

    if (async->async_flags & ASYNC_SW_IN_NEEDED) {
        /*
         * If we get this far, then we know we need to send out
         * XON or XOFF char.
         */
        char c;

        rval = B_TRUE;
        c = (async->async_flags & ASYNC_SW_IN_FLOW) ?
            async->async_stopc : async->async_startc;
        if (DOMAIN_IS_INITDOMAIN(xen_info)) {
            (void) HYPERVISOR_console_io(CONSOLEIO_write, 1, &c);
            async->async_flags &= ~ASYNC_SW_IN_NEEDED;
            return (rval);
        } else {
            xenconsputchar(NULL, c);
        }
    }
    return (rval);
}

struct module_info xencons_info = {
    0,
    "xencons",
    0,
    INFPSZ,
    4096,
    128
};

static struct qinit xencons_rint = {
    putq,
    xenconsrsrv,
    xenconsopen,
    xenconsclose,
    NULL,
    &xencons_info,
    NULL
};

static struct qinit xencons_wint = {
    xenconswput,
    NULL,
    NULL,
    NULL,
    NULL,
    &xencons_info,
    NULL
};

struct streamtab xencons_str_info = {
    &xencons_rint,
    &xencons_wint,
    NULL,
    NULL
};

static struct cb_ops cb_xencons_ops = {
    nodev,          /* cb_open */
    nodev,          /* cb_close */
    nodev,          /* cb_strategy */
    nodev,          /* cb_print */
    nodev,          /* cb_dump */
    nodev,          /* cb_read */
    nodev,          /* cb_write */
    nodev,          /* cb_ioctl */
    nodev,          /* cb_devmap */
    nodev,          /* cb_mmap */
    nodev,          /* cb_segmap */
    nochpoll,       /* cb_chpoll */
    ddi_prop_op,        /* cb_prop_op */
    &xencons_str_info,      /* cb_stream */
    D_MP            /* cb_flag */
};

struct dev_ops xencons_ops = {
    DEVO_REV,       /* devo_rev */
    0,          /* devo_refcnt */
    xenconsinfo,        /* devo_getinfo */
    nulldev,        /* devo_identify */
    nulldev,        /* devo_probe */
    xenconsattach,      /* devo_attach */
    xenconsdetach,      /* devo_detach */
    nodev,          /* devo_reset */
    &cb_xencons_ops,    /* devo_cb_ops */
    NULL,           /* devo_bus_ops */
    NULL,           /* devo_power */
    ddi_quiesce_not_needed,     /* devo_quiesce */
};

static struct modldrv modldrv = {
    &mod_driverops, /* Type of module.  This one is a driver */
    "virtual console driver",
    &xencons_ops,   /* driver ops */
};

static struct modlinkage modlinkage = {
    MODREV_1,
    (void *)&modldrv,
    NULL
};

int
_init(void)
{
    int rv;

    if ((rv = ddi_soft_state_init(&xencons_soft_state,
        sizeof (struct xencons), 1)) != 0)
        return (rv);
    if ((rv = mod_install(&modlinkage)) != 0) {
        ddi_soft_state_fini(&xencons_soft_state);
        return (rv);
    }
    DEBUGCONT2(XENCONS_DEBUG_INIT, "%s, debug = %x\n",
        modldrv.drv_linkinfo, debug);
    return (0);
}

int
_fini(void)
{
    int rv;

    if ((rv = mod_remove(&modlinkage)) != 0)
        return (rv);

    ddi_soft_state_fini(&xencons_soft_state);
    return (0);
}

int
_info(struct modinfo *modinfop)
{
    return (mod_info(&modlinkage, modinfop));
}