Expand PMF_FN_* macros.

[netbsd-mini2440.git] / sys / dev / ata / ata.c

/*      $NetBSD: ata.c,v 1.109 2009/11/12 19:20:08 dyoung Exp $ */

/*
 * Copyright (c) 1998, 2001 Manuel Bouyer.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ata.c,v 1.109 2009/11/12 19:20:08 dyoung Exp $");

#include "opt_ata.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/device.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <sys/proc.h>
#include <sys/pool.h>
#include <sys/kthread.h>
#include <sys/errno.h>
#include <sys/ataio.h>
#include <sys/kmem.h>
#include <sys/simplelock.h>
#include <sys/intr.h>
#include <sys/bus.h>
#include <sys/once.h>

#include <dev/ata/ataconf.h>
#include <dev/ata/atareg.h>
#include <dev/ata/atavar.h>
#include <dev/ic/wdcvar.h>      /* for PIOBM */

#include "locators.h"

#include "atapibus.h"
#include "ataraid.h"

#if NATARAID > 0
#include <dev/ata/ata_raidvar.h>
#endif

#define DEBUG_FUNCS  0x08
#define DEBUG_PROBE  0x10
#define DEBUG_DETACH 0x20
#define DEBUG_XFERS  0x40
#ifdef ATADEBUG
int atadebug_mask = 0;
#define ATADEBUG_PRINT(args, level) \
        if (atadebug_mask & (level)) \
                printf args
#else
#define ATADEBUG_PRINT(args, level)
#endif

static struct pool ata_xfer_pool;

/*
 * A queue of atabus instances, used to ensure the same bus probe order
 * for a given hardware configuration at each boot.
 */
struct atabus_initq_head atabus_initq_head =
    TAILQ_HEAD_INITIALIZER(atabus_initq_head);
struct simplelock atabus_interlock = SIMPLELOCK_INITIALIZER;

/* kernel thread probing devices on a atabus. Only one probing at once */
struct lwp *atabus_configlwp;

/*****************************************************************************
 * ATA bus layer.
 *
 * ATA controllers attach an atabus instance, which handles probing the bus
 * for drives, etc.
 *****************************************************************************/

dev_type_open(atabusopen);
dev_type_close(atabusclose);
dev_type_ioctl(atabusioctl);

const struct cdevsw atabus_cdevsw = {
        atabusopen, atabusclose, noread, nowrite, atabusioctl,
        nostop, notty, nopoll, nommap, nokqfilter, D_OTHER
};

extern struct cfdriver atabus_cd;

static void atabus_childdetached(device_t, device_t);
static bool atabus_resume(device_t, pmf_qual_t);
static bool atabus_suspend(device_t, pmf_qual_t);
static void atabusconfig_thread(void *);

/*
 * atabusprint:
 *
 *      Autoconfiguration print routine used by ATA controllers when
 *      attaching an atabus instance.
 */
int
atabusprint(void *aux, const char *pnp)
{
        struct ata_channel *chan = aux;

        if (pnp)
                aprint_normal("atabus at %s", pnp);
        aprint_normal(" channel %d", chan->ch_channel);

        return (UNCONF);
}

/*
 * ataprint:
 *
 *      Autoconfiguration print routine.
 */
int
ataprint(void *aux, const char *pnp)
{
        struct ata_device *adev = aux;

        if (pnp)
                aprint_normal("wd at %s", pnp);
        aprint_normal(" drive %d", adev->adev_drv_data->drive);

        return (UNCONF);
}

/*
 * ata_channel_attach:
 *
 *      Common parts of attaching an atabus to an ATA controller channel.
 */
void
ata_channel_attach(struct ata_channel *chp)
{

        if (chp->ch_flags & ATACH_DISABLED)
                return;

        /* XXX callout_destroy */
        callout_init(&chp->ch_callout, 0);

        TAILQ_INIT(&chp->ch_queue->queue_xfer);
        chp->ch_queue->queue_freeze = 0;
        chp->ch_queue->queue_flags = 0;
        chp->ch_queue->active_xfer = NULL;

        chp->atabus = config_found_ia(chp->ch_atac->atac_dev, "ata", chp,
                atabusprint);
}

static void
atabusconfig(struct atabus_softc *atabus_sc)
{
        struct ata_channel *chp = atabus_sc->sc_chan;
        struct atac_softc *atac = chp->ch_atac;
        struct atabus_initq *atabus_initq = NULL;
        int i, s, error;

        /* we are in the atabus's thread context */
        s = splbio();
        chp->ch_flags |= ATACH_TH_RUN;
        splx(s);

        /* Probe for the drives. */
        /* XXX for SATA devices we will power up all drives at once */
        (*atac->atac_probe)(chp);

        ATADEBUG_PRINT(("atabusattach: ch_drive_flags 0x%x 0x%x\n",
            chp->ch_drive[0].drive_flags, chp->ch_drive[1].drive_flags),
            DEBUG_PROBE);

        /* next operations will occurs in a separate thread */
        s = splbio();
        chp->ch_flags &= ~ATACH_TH_RUN;
        splx(s);

        /* Make sure the devices probe in atabus order to avoid jitter. */
        simple_lock(&atabus_interlock);
        while(1) {
                atabus_initq = TAILQ_FIRST(&atabus_initq_head);
                if (atabus_initq->atabus_sc == atabus_sc)
                        break;
                ltsleep(&atabus_initq_head, PRIBIO, "ata_initq", 0,
                    &atabus_interlock);
        }
        simple_unlock(&atabus_interlock);

        /* If no drives, abort here */
        for (i = 0; i < chp->ch_ndrive; i++)
                if ((chp->ch_drive[i].drive_flags & DRIVE) != 0)
                        break;
        if (i == chp->ch_ndrive)
                goto out;

        /* Shortcut in case we've been shutdown */
        if (chp->ch_flags & ATACH_SHUTDOWN)
                goto out;


        if ((error = kthread_create(PRI_NONE, 0, NULL, atabusconfig_thread,
            atabus_sc, &atabus_configlwp,
            "%scnf", device_xname(atac->atac_dev))) != 0)
                aprint_error_dev(atac->atac_dev,
                    "unable to create config thread: error %d\n", error);
        return;

 out:
        simple_lock(&atabus_interlock);
        TAILQ_REMOVE(&atabus_initq_head, atabus_initq, atabus_initq);
        simple_unlock(&atabus_interlock);

        free(atabus_initq, M_DEVBUF);
        wakeup(&atabus_initq_head);

        ata_delref(chp);

        config_pending_decr();
}

/*
 * atabus_configthread: finish attach of atabus's childrens, in a separate
 * kernel thread.
 */
static void
atabusconfig_thread(void *arg)
{
        struct atabus_softc *atabus_sc = arg;
        struct ata_channel *chp = atabus_sc->sc_chan;
        struct atac_softc *atac = chp->ch_atac;
        int i, s;
        struct atabus_initq *atabus_initq = NULL;

        simple_lock(&atabus_interlock);
        atabus_initq = TAILQ_FIRST(&atabus_initq_head);
        simple_unlock(&atabus_interlock);
        KASSERT(atabus_initq->atabus_sc == atabus_sc);
        /*
         * Attach an ATAPI bus, if needed.
         */
        for (i = 0; i < chp->ch_ndrive; i++) {
                if (chp->ch_drive[i].drive_flags & DRIVE_ATAPI) {
#if NATAPIBUS > 0
                        (*atac->atac_atapibus_attach)(atabus_sc);
#else
                        /*
                         * Fake the autoconfig "not configured" message
                         */
                        aprint_normal("atapibus at %s not configured\n",
                            device_xname(atac->atac_dev));
                        chp->atapibus = NULL;
                        s = splbio();
                        for (i = 0; i < chp->ch_ndrive; i++)
                                chp->ch_drive[i].drive_flags &= ~DRIVE_ATAPI;
                        splx(s);
#endif
                        break;
                }
        }

        for (i = 0; i < chp->ch_ndrive; i++) {
                struct ata_device adev;
                if ((chp->ch_drive[i].drive_flags &
                    (DRIVE_ATA | DRIVE_OLD)) == 0) {
                        continue;
                }
                memset(&adev, 0, sizeof(struct ata_device));
                adev.adev_bustype = atac->atac_bustype_ata;
                adev.adev_channel = chp->ch_channel;
                adev.adev_openings = 1;
                adev.adev_drv_data = &chp->ch_drive[i];
                chp->ata_drives[i] = config_found_ia(atabus_sc->sc_dev,
                    "ata_hl", &adev, ataprint);
                if (chp->ata_drives[i] != NULL)
                        ata_probe_caps(&chp->ch_drive[i]);
                else {
                        s = splbio();
                        chp->ch_drive[i].drive_flags &=
                            ~(DRIVE_ATA | DRIVE_OLD);
                        splx(s);
                }
        }

        /* now that we know the drives, the controller can set its modes */
        if (atac->atac_set_modes) {
                (*atac->atac_set_modes)(chp);
                ata_print_modes(chp);
        }
#if NATARAID > 0
        if (atac->atac_cap & ATAC_CAP_RAID)
                for (i = 0; i < chp->ch_ndrive; i++)
                        if (chp->ata_drives[i] != NULL)
                                ata_raid_check_component(chp->ata_drives[i]);
#endif /* NATARAID > 0 */

        /*
         * reset drive_flags for unattached devices, reset state for attached
         * ones
         */
        s = splbio();
        for (i = 0; i < chp->ch_ndrive; i++) {
                if (chp->ch_drive[i].drv_softc == NULL)
                        chp->ch_drive[i].drive_flags = 0;
                else
                        chp->ch_drive[i].state = 0;
        }
        splx(s);

        simple_lock(&atabus_interlock);
        TAILQ_REMOVE(&atabus_initq_head, atabus_initq, atabus_initq);
        simple_unlock(&atabus_interlock);

        free(atabus_initq, M_DEVBUF);
        wakeup(&atabus_initq_head);

        ata_delref(chp);

        config_pending_decr();
        kthread_exit(0);
}

/*
 * atabus_thread:
 *
 *      Worker thread for the ATA bus.
 */
static void
atabus_thread(void *arg)
{
        struct atabus_softc *sc = arg;
        struct ata_channel *chp = sc->sc_chan;
        struct ata_xfer *xfer;
        int i, s;

        s = splbio();
        chp->ch_flags |= ATACH_TH_RUN;

        /*
         * Probe the drives.  Reset all flags to 0 to indicate to controllers
         * that can re-probe that all drives must be probed..
         *
         * Note: ch_ndrive may be changed during the probe.
         */
        for (i = 0; i < ATA_MAXDRIVES; i++)
                chp->ch_drive[i].drive_flags = 0;
        splx(s);

        atabusconfig(sc);

        s = splbio();
        for (;;) {
                if ((chp->ch_flags & (ATACH_TH_RESET | ATACH_SHUTDOWN)) == 0 &&
                    (chp->ch_queue->active_xfer == NULL ||
                     chp->ch_queue->queue_freeze == 0)) {
                        chp->ch_flags &= ~ATACH_TH_RUN;
                        (void) tsleep(&chp->ch_thread, PRIBIO, "atath", 0);
                        chp->ch_flags |= ATACH_TH_RUN;
                }
                if (chp->ch_flags & ATACH_SHUTDOWN) {
                        break;
                }
                if (chp->ch_flags & ATACH_TH_RESET) {
                        /*
                         * ata_reset_channel() will freeze 2 times, so
                         * unfreeze one time. Not a problem as we're at splbio
                         */
                        chp->ch_queue->queue_freeze--;
                        ata_reset_channel(chp, AT_WAIT | chp->ch_reset_flags);
                } else if (chp->ch_queue->active_xfer != NULL &&
                           chp->ch_queue->queue_freeze == 1) {
                        /*
                         * Caller has bumped queue_freeze, decrease it.
                         */
                        chp->ch_queue->queue_freeze--;
                        xfer = chp->ch_queue->active_xfer;
                        KASSERT(xfer != NULL);
                        (*xfer->c_start)(xfer->c_chp, xfer);
                } else if (chp->ch_queue->queue_freeze > 1)
                        panic("ata_thread: queue_freeze");
        }
        splx(s);
        chp->ch_thread = NULL;
        wakeup(&chp->ch_flags);
        kthread_exit(0);
}

/*
 * atabus_match:
 *
 *      Autoconfiguration match routine.
 */
static int
atabus_match(device_t parent, cfdata_t cf, void *aux)
{
        struct ata_channel *chp = aux;

        if (chp == NULL)
                return (0);

        if (cf->cf_loc[ATACF_CHANNEL] != chp->ch_channel &&
            cf->cf_loc[ATACF_CHANNEL] != ATACF_CHANNEL_DEFAULT)
                return (0);

        return (1);
}

static int
atabus_xferpool_init(void)
{

        pool_init(&ata_xfer_pool, sizeof(struct ata_xfer), 0, 0, 0, "ataspl",
            NULL, IPL_BIO);
        return 0;
}

/*
 * atabus_attach:
 *
 *      Autoconfiguration attach routine.
 */
static void
atabus_attach(device_t parent, device_t self, void *aux)
{
        struct atabus_softc *sc = device_private(self);
        struct ata_channel *chp = aux;
        struct atabus_initq *initq;
        static ONCE_DECL(poolinit_ctrl);
        int error;

        sc->sc_chan = chp;

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

        sc->sc_dev = self;

        if (ata_addref(chp))
                return;

        RUN_ONCE(&poolinit_ctrl, atabus_xferpool_init);

        initq = malloc(sizeof(*initq), M_DEVBUF, M_WAITOK);
        initq->atabus_sc = sc;
        TAILQ_INSERT_TAIL(&atabus_initq_head, initq, atabus_initq);
        config_pending_incr();

        if ((error = kthread_create(PRI_NONE, 0, NULL, atabus_thread, sc,
            &chp->ch_thread, "%s", device_xname(self))) != 0)
                aprint_error_dev(self,
                    "unable to create kernel thread: error %d\n", error);

        if (!pmf_device_register(self, atabus_suspend, atabus_resume))
                aprint_error_dev(self, "couldn't establish power handler\n");
}

/*
 * atabus_detach:
 *
 *      Autoconfiguration detach routine.
 */
static int
atabus_detach(device_t self, int flags)
{
        struct atabus_softc *sc = device_private(self);
        struct ata_channel *chp = sc->sc_chan;
        device_t dev = NULL;
        int s, i, error = 0;

        /* Shutdown the channel. */
        s = splbio();           /* XXX ALSO NEED AN INTERLOCK HERE. */
        chp->ch_flags |= ATACH_SHUTDOWN;
        splx(s);

        wakeup(&chp->ch_thread);

        while (chp->ch_thread != NULL)
                (void) tsleep(&chp->ch_flags, PRIBIO, "atadown", 0);


        /*
         * Detach atapibus and its children.
         */
        if ((dev = chp->atapibus) != NULL) {
                ATADEBUG_PRINT(("atabus_detach: %s: detaching %s\n",
                    device_xname(self), device_xname(dev)), DEBUG_DETACH);

                error = config_detach(dev, flags);
                if (error)
                        goto out;
                KASSERT(chp->atapibus == NULL);
        }

        /*
         * Detach our other children.
         */
        for (i = 0; i < chp->ch_ndrive; i++) {
                if (chp->ch_drive[i].drive_flags & DRIVE_ATAPI)
                        continue;
                if ((dev = chp->ata_drives[i]) != NULL) {
                        ATADEBUG_PRINT(("%s.%d: %s: detaching %s\n", __func__,
                            __LINE__, device_xname(self), device_xname(dev)),
                            DEBUG_DETACH);
                        KASSERT(chp->ch_drive[i].drv_softc ==
                                chp->ata_drives[i]);
                        error = config_detach(dev, flags);
                        if (error)
                                goto out;
                        KASSERT(chp->ata_drives[i] == NULL);
                }
        }

 out:
#ifdef ATADEBUG
        if (dev != NULL && error != 0)
                ATADEBUG_PRINT(("%s: %s: error %d detaching %s\n", __func__,
                    device_xname(self), error, device_xname(dev)),
                    DEBUG_DETACH);
#endif /* ATADEBUG */

        return (error);
}

void
atabus_childdetached(device_t self, device_t child)
{
        bool found = false;
        struct atabus_softc *sc = device_private(self);
        struct ata_channel *chp = sc->sc_chan;
        int i;

        /*
         * atapibus detached.
         */
        if (child == chp->atapibus) {
                chp->atapibus = NULL;
                found = true;
        }

        /*
         * Detach our other children.
         */
        for (i = 0; i < chp->ch_ndrive; i++) {
                if (chp->ch_drive[i].drive_flags & DRIVE_ATAPI)
                        continue;
                if (child == chp->ata_drives[i]) {
                        KASSERT(chp->ata_drives[i] ==
                                chp->ch_drive[i].drv_softc);
                        chp->ata_drives[i] = NULL;
                        chp->ch_drive[i].drv_softc = NULL;
                        chp->ch_drive[i].drive_flags = 0;
                        found = true;
                }
        }

        if (!found)
                panic("%s: unknown child %p", device_xname(self),
                    (const void *)child);
}

CFATTACH_DECL3_NEW(atabus, sizeof(struct atabus_softc),
    atabus_match, atabus_attach, atabus_detach, NULL, NULL,
    atabus_childdetached, DVF_DETACH_SHUTDOWN);

/*****************************************************************************
 * Common ATA bus operations.
 *****************************************************************************/

/* Get the disk's parameters */
int
ata_get_params(struct ata_drive_datas *drvp, u_int8_t flags,
    struct ataparams *prms)
{
        struct ata_command ata_c;
        struct ata_channel *chp = drvp->chnl_softc;
        struct atac_softc *atac = chp->ch_atac;
        char *tb;
        int i, rv;
        u_int16_t *p;

        ATADEBUG_PRINT(("%s\n", __func__), DEBUG_FUNCS);

        tb = kmem_zalloc(DEV_BSIZE, KM_SLEEP);
        memset(prms, 0, sizeof(struct ataparams));
        memset(&ata_c, 0, sizeof(struct ata_command));

        if (drvp->drive_flags & DRIVE_ATA) {
                ata_c.r_command = WDCC_IDENTIFY;
                ata_c.r_st_bmask = WDCS_DRDY;
                ata_c.r_st_pmask = WDCS_DRQ;
                ata_c.timeout = 3000; /* 3s */
        } else if (drvp->drive_flags & DRIVE_ATAPI) {
                ata_c.r_command = ATAPI_IDENTIFY_DEVICE;
                ata_c.r_st_bmask = 0;
                ata_c.r_st_pmask = WDCS_DRQ;
                ata_c.timeout = 10000; /* 10s */
        } else {
                ATADEBUG_PRINT(("ata_get_parms: no disks\n"),
                    DEBUG_FUNCS|DEBUG_PROBE);
                rv = CMD_ERR;
                goto out;
        }
        ata_c.flags = AT_READ | flags;
        ata_c.data = tb;
        ata_c.bcount = DEV_BSIZE;
        if ((*atac->atac_bustype_ata->ata_exec_command)(drvp,
                                                &ata_c) != ATACMD_COMPLETE) {
                ATADEBUG_PRINT(("ata_get_parms: wdc_exec_command failed\n"),
                    DEBUG_FUNCS|DEBUG_PROBE);
                rv = CMD_AGAIN;
                goto out;
        }
        if (ata_c.flags & (AT_ERROR | AT_TIMEOU | AT_DF)) {
                ATADEBUG_PRINT(("ata_get_parms: ata_c.flags=0x%x\n",
                    ata_c.flags), DEBUG_FUNCS|DEBUG_PROBE);
                rv = CMD_ERR;
                goto out;
        }
        /* if we didn't read any data something is wrong */
        if ((ata_c.flags & AT_XFDONE) == 0) {
                rv = CMD_ERR;
                goto out;
        }

        /* Read in parameter block. */
        memcpy(prms, tb, sizeof(struct ataparams));

        /*
         * Shuffle string byte order.
         * ATAPI NEC, Mitsumi and Pioneer drives and
         * old ATA TDK CompactFlash cards
         * have different byte order.
         */
#if BYTE_ORDER == BIG_ENDIAN
# define M(n)   prms->atap_model[(n) ^ 1]
#else
# define M(n)   prms->atap_model[n]
#endif
        if (
#if BYTE_ORDER == BIG_ENDIAN
            !
#endif
            ((drvp->drive_flags & DRIVE_ATAPI) ?
             ((M(0) == 'N' && M(1) == 'E') ||
              (M(0) == 'F' && M(1) == 'X') ||
              (M(0) == 'P' && M(1) == 'i')) :
             ((M(0) == 'T' && M(1) == 'D' && M(2) == 'K')))) {
                rv = CMD_OK;
                goto out;
             }
#undef M
        for (i = 0; i < sizeof(prms->atap_model); i += 2) {
                p = (u_int16_t *)(prms->atap_model + i);
                *p = bswap16(*p);
        }
        for (i = 0; i < sizeof(prms->atap_serial); i += 2) {
                p = (u_int16_t *)(prms->atap_serial + i);
                *p = bswap16(*p);
        }
        for (i = 0; i < sizeof(prms->atap_revision); i += 2) {
                p = (u_int16_t *)(prms->atap_revision + i);
                *p = bswap16(*p);
        }

        rv = CMD_OK;
 out:
        kmem_free(tb, DEV_BSIZE);
        return rv;
}

int
ata_set_mode(struct ata_drive_datas *drvp, u_int8_t mode, u_int8_t flags)
{
        struct ata_command ata_c;
        struct ata_channel *chp = drvp->chnl_softc;
        struct atac_softc *atac = chp->ch_atac;

        ATADEBUG_PRINT(("ata_set_mode=0x%x\n", mode), DEBUG_FUNCS);
        memset(&ata_c, 0, sizeof(struct ata_command));

        ata_c.r_command = SET_FEATURES;
        ata_c.r_st_bmask = 0;
        ata_c.r_st_pmask = 0;
        ata_c.r_features = WDSF_SET_MODE;
        ata_c.r_count = mode;
        ata_c.flags = flags;
        ata_c.timeout = 1000; /* 1s */
        if ((*atac->atac_bustype_ata->ata_exec_command)(drvp,
                                                &ata_c) != ATACMD_COMPLETE)
                return CMD_AGAIN;
        if (ata_c.flags & (AT_ERROR | AT_TIMEOU | AT_DF)) {
                return CMD_ERR;
        }
        return CMD_OK;
}

#if NATA_DMA
void
ata_dmaerr(struct ata_drive_datas *drvp, int flags)
{
        /*
         * Downgrade decision: if we get NERRS_MAX in NXFER.
         * We start with n_dmaerrs set to NERRS_MAX-1 so that the
         * first error within the first NXFER ops will immediatly trigger
         * a downgrade.
         * If we got an error and n_xfers is bigger than NXFER reset counters.
         */
        drvp->n_dmaerrs++;
        if (drvp->n_dmaerrs >= NERRS_MAX && drvp->n_xfers <= NXFER) {
                ata_downgrade_mode(drvp, flags);
                drvp->n_dmaerrs = NERRS_MAX-1;
                drvp->n_xfers = 0;
                return;
        }
        if (drvp->n_xfers > NXFER) {
                drvp->n_dmaerrs = 1; /* just got an error */
                drvp->n_xfers = 1; /* restart counting from this error */
        }
}
#endif  /* NATA_DMA */

/*
 * freeze the queue and wait for the controller to be idle. Caller has to
 * unfreeze/restart the queue
 */
void
ata_queue_idle(struct ata_queue *queue)
{
        int s = splbio();
        queue->queue_freeze++;
        while (queue->active_xfer != NULL) {
                queue->queue_flags |= QF_IDLE_WAIT;
                tsleep(&queue->queue_flags, PRIBIO, "qidl", 0);
        }
        splx(s);
}

/*
 * Add a command to the queue and start controller.
 *
 * MUST BE CALLED AT splbio()!
 */
void
ata_exec_xfer(struct ata_channel *chp, struct ata_xfer *xfer)
{

        ATADEBUG_PRINT(("ata_exec_xfer %p channel %d drive %d\n", xfer,
            chp->ch_channel, xfer->c_drive), DEBUG_XFERS);

        /* complete xfer setup */
        xfer->c_chp = chp;

        /* insert at the end of command list */
        TAILQ_INSERT_TAIL(&chp->ch_queue->queue_xfer, xfer, c_xferchain);
        ATADEBUG_PRINT(("atastart from ata_exec_xfer, flags 0x%x\n",
            chp->ch_flags), DEBUG_XFERS);
        /*
         * if polling and can sleep, wait for the xfer to be at head of queue
         */
        if ((xfer->c_flags & (C_POLL | C_WAIT)) ==  (C_POLL | C_WAIT)) {
                while (chp->ch_queue->active_xfer != NULL ||
                    TAILQ_FIRST(&chp->ch_queue->queue_xfer) != xfer) {
                        xfer->c_flags |= C_WAITACT;
                        tsleep(xfer, PRIBIO, "ataact", 0);
                        xfer->c_flags &= ~C_WAITACT;
                        if (xfer->c_flags & C_FREE) {
                                ata_free_xfer(chp, xfer);
                                return;
                        }
                }
        }
        atastart(chp);
}

/*
 * Start I/O on a controller, for the given channel.
 * The first xfer may be not for our channel if the channel queues
 * are shared.
 *
 * MUST BE CALLED AT splbio()!
 */
void
atastart(struct ata_channel *chp)
{
        struct atac_softc *atac = chp->ch_atac;
        struct ata_xfer *xfer;

#ifdef ATA_DEBUG
        int spl1, spl2;

        spl1 = splbio();
        spl2 = splbio();
        if (spl2 != spl1) {
                printf("atastart: not at splbio()\n");
                panic("atastart");
        }
        splx(spl2);
        splx(spl1);
#endif /* ATA_DEBUG */

        /* is there a xfer ? */
        if ((xfer = TAILQ_FIRST(&chp->ch_queue->queue_xfer)) == NULL)
                return;

        /* adjust chp, in case we have a shared queue */
        chp = xfer->c_chp;

        if (chp->ch_queue->active_xfer != NULL) {
                return; /* channel aleady active */
        }
        if (__predict_false(chp->ch_queue->queue_freeze > 0)) {
                if (chp->ch_queue->queue_flags & QF_IDLE_WAIT) {
                        chp->ch_queue->queue_flags &= ~QF_IDLE_WAIT;
                        wakeup(&chp->ch_queue->queue_flags);
                }
                return; /* queue frozen */
        }
        /*
         * if someone is waiting for the command to be active, wake it up
         * and let it process the command
         */
        if (xfer->c_flags & C_WAITACT) {
                ATADEBUG_PRINT(("atastart: xfer %p channel %d drive %d "
                    "wait active\n", xfer, chp->ch_channel, xfer->c_drive),
                    DEBUG_XFERS);
                wakeup(xfer);
                return;
        }
#ifdef DIAGNOSTIC
        if ((chp->ch_flags & ATACH_IRQ_WAIT) != 0)
                panic("atastart: channel waiting for irq");
#endif
        if (atac->atac_claim_hw)
                if (!(*atac->atac_claim_hw)(chp, 0))
                        return;

        ATADEBUG_PRINT(("atastart: xfer %p channel %d drive %d\n", xfer,
            chp->ch_channel, xfer->c_drive), DEBUG_XFERS);
        if (chp->ch_drive[xfer->c_drive].drive_flags & DRIVE_RESET) {
                chp->ch_drive[xfer->c_drive].drive_flags &= ~DRIVE_RESET;
                chp->ch_drive[xfer->c_drive].state = 0;
        }
        chp->ch_queue->active_xfer = xfer;
        TAILQ_REMOVE(&chp->ch_queue->queue_xfer, xfer, c_xferchain);

        if (atac->atac_cap & ATAC_CAP_NOIRQ)
                KASSERT(xfer->c_flags & C_POLL);

        xfer->c_start(chp, xfer);
}

struct ata_xfer *
ata_get_xfer(int flags)
{
        struct ata_xfer *xfer;
        int s;

        s = splbio();
        xfer = pool_get(&ata_xfer_pool,
            ((flags & ATAXF_NOSLEEP) != 0 ? PR_NOWAIT : PR_WAITOK));
        splx(s);
        if (xfer != NULL) {
                memset(xfer, 0, sizeof(struct ata_xfer));
        }
        return xfer;
}

void
ata_free_xfer(struct ata_channel *chp, struct ata_xfer *xfer)
{
        struct atac_softc *atac = chp->ch_atac;
        int s;

        if (xfer->c_flags & C_WAITACT) {
                /* Someone is waiting for this xfer, so we can't free now */
                xfer->c_flags |= C_FREE;
                wakeup(xfer);
                return;
        }

#if NATA_PIOBM          /* XXX wdc dependent code */
        if (xfer->c_flags & C_PIOBM) {
                struct wdc_softc *wdc = CHAN_TO_WDC(chp);

                /* finish the busmastering PIO */
                (*wdc->piobm_done)(wdc->dma_arg,
                    chp->ch_channel, xfer->c_drive);
                chp->ch_flags &= ~(ATACH_DMA_WAIT | ATACH_PIOBM_WAIT | ATACH_IRQ_WAIT);
        }
#endif

        if (atac->atac_free_hw)
                (*atac->atac_free_hw)(chp);
        s = splbio();
        pool_put(&ata_xfer_pool, xfer);
        splx(s);
}

/*
 * Kill off all pending xfers for a ata_channel.
 *
 * Must be called at splbio().
 */
void
ata_kill_pending(struct ata_drive_datas *drvp)
{
        struct ata_channel *chp = drvp->chnl_softc;
        struct ata_xfer *xfer, *next_xfer;
        int s = splbio();

        for (xfer = TAILQ_FIRST(&chp->ch_queue->queue_xfer);
            xfer != NULL; xfer = next_xfer) {
                next_xfer = TAILQ_NEXT(xfer, c_xferchain);
                if (xfer->c_chp != chp || xfer->c_drive != drvp->drive)
                        continue;
                TAILQ_REMOVE(&chp->ch_queue->queue_xfer, xfer, c_xferchain);
                (*xfer->c_kill_xfer)(chp, xfer, KILL_GONE);
        }

        while ((xfer = chp->ch_queue->active_xfer) != NULL) {
                if (xfer->c_chp == chp && xfer->c_drive == drvp->drive) {
                        drvp->drive_flags |= DRIVE_WAITDRAIN;
                        (void) tsleep(&chp->ch_queue->active_xfer,
                            PRIBIO, "atdrn", 0);
                } else {
                        /* no more xfer for us */
                        break;
                }
        }
        splx(s);
}

/*
 * ata_reset_channel:
 *
 *      Reset and ATA channel.
 *
 *      MUST BE CALLED AT splbio()!
 */
void
ata_reset_channel(struct ata_channel *chp, int flags)
{
        struct atac_softc *atac = chp->ch_atac;
        int drive;

#ifdef ATA_DEBUG
        int spl1, spl2;

        spl1 = splbio();
        spl2 = splbio();
        if (spl2 != spl1) {
                printf("ata_reset_channel: not at splbio()\n");
                panic("ata_reset_channel");
        }
        splx(spl2);
        splx(spl1);
#endif /* ATA_DEBUG */

        chp->ch_queue->queue_freeze++;

        /*
         * If we can poll or wait it's OK, otherwise wake up the
         * kernel thread to do it for us.
         */
        ATADEBUG_PRINT(("ata_reset_channel flags 0x%x ch_flags 0x%x\n",
            flags, chp->ch_flags), DEBUG_FUNCS | DEBUG_XFERS);
        if ((flags & (AT_POLL | AT_WAIT)) == 0) {
                if (chp->ch_flags & ATACH_TH_RESET) {
                        /* No need to schedule a reset more than one time. */
                        chp->ch_queue->queue_freeze--;
                        return;
                }
                chp->ch_flags |= ATACH_TH_RESET;
                chp->ch_reset_flags = flags & (AT_RST_EMERG | AT_RST_NOCMD);
                wakeup(&chp->ch_thread);
                return;
        }

        (*atac->atac_bustype_ata->ata_reset_channel)(chp, flags);

        for (drive = 0; drive < chp->ch_ndrive; drive++)
                chp->ch_drive[drive].state = 0;

        chp->ch_flags &= ~ATACH_TH_RESET;
        if ((flags & AT_RST_EMERG) == 0)  {
                chp->ch_queue->queue_freeze--;
                atastart(chp);
        } else {
                /* make sure that we can use polled commands */
                TAILQ_INIT(&chp->ch_queue->queue_xfer);
                chp->ch_queue->queue_freeze = 0;
                chp->ch_queue->active_xfer = NULL;
        }
}

int
ata_addref(struct ata_channel *chp)
{
        struct atac_softc *atac = chp->ch_atac;
        struct scsipi_adapter *adapt = &atac->atac_atapi_adapter._generic;
        int s, error = 0;

        s = splbio();
        if (adapt->adapt_refcnt++ == 0 &&
            adapt->adapt_enable != NULL) {
                error = (*adapt->adapt_enable)(atac->atac_dev, 1);
                if (error)
                        adapt->adapt_refcnt--;
        }
        splx(s);
        return (error);
}

void
ata_delref(struct ata_channel *chp)
{
        struct atac_softc *atac = chp->ch_atac;
        struct scsipi_adapter *adapt = &atac->atac_atapi_adapter._generic;
        int s;

        s = splbio();
        if (adapt->adapt_refcnt-- == 1 &&
            adapt->adapt_enable != NULL)
                (void) (*adapt->adapt_enable)(atac->atac_dev, 0);
        splx(s);
}

void
ata_print_modes(struct ata_channel *chp)
{
        struct atac_softc *atac = chp->ch_atac;
        int drive;
        struct ata_drive_datas *drvp;

        for (drive = 0; drive < chp->ch_ndrive; drive++) {
                drvp = &chp->ch_drive[drive];
                if ((drvp->drive_flags & DRIVE) == 0 || drvp->drv_softc == NULL)
                        continue;
                aprint_verbose("%s(%s:%d:%d): using PIO mode %d",
                        device_xname(drvp->drv_softc),
                        device_xname(atac->atac_dev),
                        chp->ch_channel, drvp->drive, drvp->PIO_mode);
#if NATA_DMA
                if (drvp->drive_flags & DRIVE_DMA)
                        aprint_verbose(", DMA mode %d", drvp->DMA_mode);
#if NATA_UDMA
                if (drvp->drive_flags & DRIVE_UDMA) {
                        aprint_verbose(", Ultra-DMA mode %d", drvp->UDMA_mode);
                        if (drvp->UDMA_mode == 2)
                                aprint_verbose(" (Ultra/33)");
                        else if (drvp->UDMA_mode == 4)
                                aprint_verbose(" (Ultra/66)");
                        else if (drvp->UDMA_mode == 5)
                                aprint_verbose(" (Ultra/100)");
                        else if (drvp->UDMA_mode == 6)
                                aprint_verbose(" (Ultra/133)");
                }
#endif  /* NATA_UDMA */
#endif  /* NATA_DMA */
#if NATA_DMA || NATA_PIOBM
                if (0
#if NATA_DMA
                    || (drvp->drive_flags & (DRIVE_DMA | DRIVE_UDMA))
#endif
#if NATA_PIOBM
                    /* PIOBM capable controllers use DMA for PIO commands */
                    || (atac->atac_cap & ATAC_CAP_PIOBM)
#endif
                    )
                        aprint_verbose(" (using DMA)");
#endif  /* NATA_DMA || NATA_PIOBM */
                aprint_verbose("\n");
        }
}

#if NATA_DMA
/*
 * downgrade the transfer mode of a drive after an error. return 1 if
 * downgrade was possible, 0 otherwise.
 *
 * MUST BE CALLED AT splbio()!
 */
int
ata_downgrade_mode(struct ata_drive_datas *drvp, int flags)
{
        struct ata_channel *chp = drvp->chnl_softc;
        struct atac_softc *atac = chp->ch_atac;
        device_t drv_dev = drvp->drv_softc;
        int cf_flags = device_cfdata(drv_dev)->cf_flags;

        /* if drive or controller don't know its mode, we can't do much */
        if ((drvp->drive_flags & DRIVE_MODE) == 0 ||
            (atac->atac_set_modes == NULL))
                return 0;
        /* current drive mode was set by a config flag, let it this way */
        if ((cf_flags & ATA_CONFIG_PIO_SET) ||
            (cf_flags & ATA_CONFIG_DMA_SET) ||
            (cf_flags & ATA_CONFIG_UDMA_SET))
                return 0;

#if NATA_UDMA
        /*
         * If we were using Ultra-DMA mode, downgrade to the next lower mode.
         */
        if ((drvp->drive_flags & DRIVE_UDMA) && drvp->UDMA_mode >= 2) {
                drvp->UDMA_mode--;
                aprint_error_dev(drv_dev,
                    "transfer error, downgrading to Ultra-DMA mode %d\n",
                    drvp->UDMA_mode);
        }
#endif

        /*
         * If we were using ultra-DMA, don't downgrade to multiword DMA.
         */
        else if (drvp->drive_flags & (DRIVE_DMA | DRIVE_UDMA)) {
                drvp->drive_flags &= ~(DRIVE_DMA | DRIVE_UDMA);
                drvp->PIO_mode = drvp->PIO_cap;
                aprint_error_dev(drv_dev,
                    "transfer error, downgrading to PIO mode %d\n",
                    drvp->PIO_mode);
        } else /* already using PIO, can't downgrade */
                return 0;

        (*atac->atac_set_modes)(chp);
        ata_print_modes(chp);
        /* reset the channel, which will schedule all drives for setup */
        ata_reset_channel(chp, flags | AT_RST_NOCMD);
        return 1;
}
#endif  /* NATA_DMA */

/*
 * Probe drive's capabilities, for use by the controller later
 * Assumes drvp points to an existing drive.
 */
void
ata_probe_caps(struct ata_drive_datas *drvp)
{
        struct ataparams params, params2;
        struct ata_channel *chp = drvp->chnl_softc;
        struct atac_softc *atac = chp->ch_atac;
        device_t drv_dev = drvp->drv_softc;
        int i, printed, s;
        const char *sep = "";
        int cf_flags;

        if (ata_get_params(drvp, AT_WAIT, &params) != CMD_OK) {
                /* IDENTIFY failed. Can't tell more about the device */
                return;
        }
        if ((atac->atac_cap & (ATAC_CAP_DATA16 | ATAC_CAP_DATA32)) ==
            (ATAC_CAP_DATA16 | ATAC_CAP_DATA32)) {
                /*
                 * Controller claims 16 and 32 bit transfers.
                 * Re-do an IDENTIFY with 32-bit transfers,
                 * and compare results.
                 */
                s = splbio();
                drvp->drive_flags |= DRIVE_CAP32;
                splx(s);
                ata_get_params(drvp, AT_WAIT, &params2);
                if (memcmp(&params, &params2, sizeof(struct ataparams)) != 0) {
                        /* Not good. fall back to 16bits */
                        s = splbio();
                        drvp->drive_flags &= ~DRIVE_CAP32;
                        splx(s);
                } else {
                        aprint_verbose_dev(drv_dev, "32-bit data port\n");
                }
        }
#if 0 /* Some ultra-DMA drives claims to only support ATA-3. sigh */
        if (params.atap_ata_major > 0x01 &&
            params.atap_ata_major != 0xffff) {
                for (i = 14; i > 0; i--) {
                        if (params.atap_ata_major & (1 << i)) {
                                aprint_verbose_dev(drv_dev,
                                    "ATA version %d\n", i);
                                drvp->ata_vers = i;
                                break;
                        }
                }
        }
#endif

        /* An ATAPI device is at last PIO mode 3 */
        if (drvp->drive_flags & DRIVE_ATAPI)
                drvp->PIO_mode = 3;

        /*
         * It's not in the specs, but it seems that some drive
         * returns 0xffff in atap_extensions when this field is invalid
         */
        if (params.atap_extensions != 0xffff &&
            (params.atap_extensions & WDC_EXT_MODES)) {
                printed = 0;
                /*
                 * XXX some drives report something wrong here (they claim to
                 * support PIO mode 8 !). As mode is coded on 3 bits in
                 * SET FEATURE, limit it to 7 (so limit i to 4).
                 * If higher mode than 7 is found, abort.
                 */
                for (i = 7; i >= 0; i--) {
                        if ((params.atap_piomode_supp & (1 << i)) == 0)
                                continue;
                        if (i > 4)
                                return;
                        /*
                         * See if mode is accepted.
                         * If the controller can't set its PIO mode,
                         * assume the defaults are good, so don't try
                         * to set it
                         */
                        if (atac->atac_set_modes)
                                /*
                                 * It's OK to pool here, it's fast enouth
                                 * to not bother waiting for interrupt
                                 */
                                if (ata_set_mode(drvp, 0x08 | (i + 3),
                                   AT_WAIT) != CMD_OK)
                                        continue;
                        if (!printed) {
                                aprint_verbose_dev(drv_dev,
                                    "drive supports PIO mode %d", i + 3);
                                sep = ",";
                                printed = 1;
                        }
                        /*
                         * If controller's driver can't set its PIO mode,
                         * get the highter one for the drive.
                         */
                        if (atac->atac_set_modes == NULL ||
                            atac->atac_pio_cap >= i + 3) {
                                drvp->PIO_mode = i + 3;
                                drvp->PIO_cap = i + 3;
                                break;
                        }
                }
                if (!printed) {
                        /*
                         * We didn't find a valid PIO mode.
                         * Assume the values returned for DMA are buggy too
                         */
                        return;
                }
                s = splbio();
                drvp->drive_flags |= DRIVE_MODE;
                splx(s);
                printed = 0;
                for (i = 7; i >= 0; i--) {
                        if ((params.atap_dmamode_supp & (1 << i)) == 0)
                                continue;
#if NATA_DMA
                        if ((atac->atac_cap & ATAC_CAP_DMA) &&
                            atac->atac_set_modes != NULL)
                                if (ata_set_mode(drvp, 0x20 | i, AT_WAIT)
                                    != CMD_OK)
                                        continue;
#endif
                        if (!printed) {
                                aprint_verbose("%s DMA mode %d", sep, i);
                                sep = ",";
                                printed = 1;
                        }
#if NATA_DMA
                        if (atac->atac_cap & ATAC_CAP_DMA) {
                                if (atac->atac_set_modes != NULL &&
                                    atac->atac_dma_cap < i)
                                        continue;
                                drvp->DMA_mode = i;
                                drvp->DMA_cap = i;
                                s = splbio();
                                drvp->drive_flags |= DRIVE_DMA;
                                splx(s);
                        }
#endif
                        break;
                }
                if (params.atap_extensions & WDC_EXT_UDMA_MODES) {
                        printed = 0;
                        for (i = 7; i >= 0; i--) {
                                if ((params.atap_udmamode_supp & (1 << i))
                                    == 0)
                                        continue;
#if NATA_UDMA
                                if (atac->atac_set_modes != NULL &&
                                    (atac->atac_cap & ATAC_CAP_UDMA))
                                        if (ata_set_mode(drvp, 0x40 | i,
                                            AT_WAIT) != CMD_OK)
                                                continue;
#endif
                                if (!printed) {
                                        aprint_verbose("%s Ultra-DMA mode %d",
                                            sep, i);
                                        if (i == 2)
                                                aprint_verbose(" (Ultra/33)");
                                        else if (i == 4)
                                                aprint_verbose(" (Ultra/66)");
                                        else if (i == 5)
                                                aprint_verbose(" (Ultra/100)");
                                        else if (i == 6)
                                                aprint_verbose(" (Ultra/133)");
                                        sep = ",";
                                        printed = 1;
                                }
#if NATA_UDMA
                                if (atac->atac_cap & ATAC_CAP_UDMA) {
                                        if (atac->atac_set_modes != NULL &&
                                            atac->atac_udma_cap < i)
                                                continue;
                                        drvp->UDMA_mode = i;
                                        drvp->UDMA_cap = i;
                                        s = splbio();
                                        drvp->drive_flags |= DRIVE_UDMA;
                                        splx(s);
                                }
#endif
                                break;
                        }
                }
                aprint_verbose("\n");
        }

        s = splbio();
        drvp->drive_flags &= ~DRIVE_NOSTREAM;
        if (drvp->drive_flags & DRIVE_ATAPI) {
                if (atac->atac_cap & ATAC_CAP_ATAPI_NOSTREAM)
                        drvp->drive_flags |= DRIVE_NOSTREAM;
        } else {
                if (atac->atac_cap & ATAC_CAP_ATA_NOSTREAM)
                        drvp->drive_flags |= DRIVE_NOSTREAM;
        }
        splx(s);

        /* Try to guess ATA version here, if it didn't get reported */
        if (drvp->ata_vers == 0) {
#if NATA_UDMA
                if (drvp->drive_flags & DRIVE_UDMA)
                        drvp->ata_vers = 4; /* should be at last ATA-4 */
                else
#endif
                if (drvp->PIO_cap > 2)
                        drvp->ata_vers = 2; /* should be at last ATA-2 */
        }
        cf_flags = device_cfdata(drv_dev)->cf_flags;
        if (cf_flags & ATA_CONFIG_PIO_SET) {
                s = splbio();
                drvp->PIO_mode =
                    (cf_flags & ATA_CONFIG_PIO_MODES) >> ATA_CONFIG_PIO_OFF;
                drvp->drive_flags |= DRIVE_MODE;
                splx(s);
        }
#if NATA_DMA
        if ((atac->atac_cap & ATAC_CAP_DMA) == 0) {
                /* don't care about DMA modes */
                return;
        }
        if (cf_flags & ATA_CONFIG_DMA_SET) {
                s = splbio();
                if ((cf_flags & ATA_CONFIG_DMA_MODES) ==
                    ATA_CONFIG_DMA_DISABLE) {
                        drvp->drive_flags &= ~DRIVE_DMA;
                } else {
                        drvp->DMA_mode = (cf_flags & ATA_CONFIG_DMA_MODES) >>
                            ATA_CONFIG_DMA_OFF;
                        drvp->drive_flags |= DRIVE_DMA | DRIVE_MODE;
                }
                splx(s);
        }
#if NATA_UDMA
        if ((atac->atac_cap & ATAC_CAP_UDMA) == 0) {
                /* don't care about UDMA modes */
                return;
        }
        if (cf_flags & ATA_CONFIG_UDMA_SET) {
                s = splbio();
                if ((cf_flags & ATA_CONFIG_UDMA_MODES) ==
                    ATA_CONFIG_UDMA_DISABLE) {
                        drvp->drive_flags &= ~DRIVE_UDMA;
                } else {
                        drvp->UDMA_mode = (cf_flags & ATA_CONFIG_UDMA_MODES) >>
                            ATA_CONFIG_UDMA_OFF;
                        drvp->drive_flags |= DRIVE_UDMA | DRIVE_MODE;
                }
                splx(s);
        }
#endif  /* NATA_UDMA */
#endif  /* NATA_DMA */
}

/* management of the /dev/atabus* devices */
int
atabusopen(dev_t dev, int flag, int fmt,
    struct lwp *l)
{
        struct atabus_softc *sc;
        int error;

        sc = device_lookup_private(&atabus_cd, minor(dev));
        if (sc == NULL)
                return (ENXIO);

        if (sc->sc_flags & ATABUSCF_OPEN)
                return (EBUSY);

        if ((error = ata_addref(sc->sc_chan)) != 0)
                return (error);

        sc->sc_flags |= ATABUSCF_OPEN;

        return (0);
}


int
atabusclose(dev_t dev, int flag, int fmt,
    struct lwp *l)
{
        struct atabus_softc *sc =
            device_lookup_private(&atabus_cd, minor(dev));

        ata_delref(sc->sc_chan);

        sc->sc_flags &= ~ATABUSCF_OPEN;

        return (0);
}

int
atabusioctl(dev_t dev, u_long cmd, void *addr, int flag,
    struct lwp *l)
{
        struct atabus_softc *sc =
            device_lookup_private(&atabus_cd, minor(dev));
        struct ata_channel *chp = sc->sc_chan;
        int min_drive, max_drive, drive;
        int error;
        int s;

        /*
         * Enforce write permission for ioctls that change the
         * state of the bus.  Host adapter specific ioctls must
         * be checked by the adapter driver.
         */
        switch (cmd) {
        case ATABUSIOSCAN:
        case ATABUSIODETACH:
        case ATABUSIORESET:
                if ((flag & FWRITE) == 0)
                        return (EBADF);
        }

        switch (cmd) {
        case ATABUSIORESET:
                s = splbio();
                ata_reset_channel(sc->sc_chan, AT_WAIT | AT_POLL);
                splx(s);
                error = 0;
                break;
        case ATABUSIOSCAN:
        {
#if 0
                struct atabusioscan_args *a=
                    (struct atabusioscan_args *)addr;
#endif
                if ((chp->ch_drive[0].drive_flags & DRIVE_OLD) ||
                    (chp->ch_drive[1].drive_flags & DRIVE_OLD))
                        return (EOPNOTSUPP);
                return (EOPNOTSUPP);
        }
        case ATABUSIODETACH:
        {
                struct atabusioscan_args *a=
                    (struct atabusioscan_args *)addr;
                if ((chp->ch_drive[0].drive_flags & DRIVE_OLD) ||
                    (chp->ch_drive[1].drive_flags & DRIVE_OLD))
                        return (EOPNOTSUPP);
                switch (a->at_dev) {
                case -1:
                        min_drive = 0;
                        max_drive = 1;
                        break;
                case 0:
                case 1:
                        min_drive = max_drive = a->at_dev;
                        break;
                default:
                        return (EINVAL);
                }
                for (drive = min_drive; drive <= max_drive; drive++) {
                        if (chp->ch_drive[drive].drv_softc != NULL) {
                                error = config_detach(
                                    chp->ch_drive[drive].drv_softc, 0);
                                if (error)
                                        return (error);
                                KASSERT(chp->ch_drive[drive].drv_softc == NULL);
                        }
                }
                error = 0;
                break;
        }
        default:
                error = ENOTTY;
        }
        return (error);
};

static bool
atabus_suspend(device_t dv, pmf_qual_t qual)
{
        struct atabus_softc *sc = device_private(dv);
        struct ata_channel *chp = sc->sc_chan;

        ata_queue_idle(chp->ch_queue);

        return true;
}

static bool
atabus_resume(device_t dv, pmf_qual_t qual)
{
        struct atabus_softc *sc = device_private(dv);
        struct ata_channel *chp = sc->sc_chan;
        int s;

        /*
         * XXX joerg: with wdc, the first channel unfreezes the controler.
         * Move this the reset and queue idling into wdc.
         */
        s = splbio();
        if (chp->ch_queue->queue_freeze == 0) {
                splx(s);
                return true;
        }
        KASSERT(chp->ch_queue->queue_freeze > 0);
        /* unfreeze the queue and reset drives */
        chp->ch_queue->queue_freeze--;
        ata_reset_channel(chp, AT_WAIT);
        splx(s);

        return true;
}