File:  [DragonFly] / src / sys / dev / disk / ata / ata-disk.c
Revision 1.9: download - view: text, annotated - select for diffs
Mon Dec 29 03:42:43 2003 UTC (10 years, 9 months ago) by dillon
Branches: MAIN
CVS tags: HEAD
FreeBSD-5.x removed the 'read interrupt arrived early' check code, for
undocumented reasons.  As far as I can tell, only the ATA_S_READY bit needs
to be set when a read interrupt arrives for a PIO read operation so reduce
the test from ATA_S_READY|ATA_S_DSC|ATA_S_DRQ to just ATA_S_READY.

Change the ATA RESET timing.  Instead of polling up to 310000 times in 100uS
intervals poll 3100 times in 10000uS intervals.  Note that 5.x polls 310
times in 100ms intervals, which is silly (an unnecessarily long polling
delay).

Add a mandatory 50ms delay after all BUSY bits have been released.  Some
ATA devices release BUSY before they are ready to accept commands.  Note
that the ATA code waits 100ms after releasing RESET, before checking BUSY,
which is probably overkill, but this does not cover the mandatory delay
that must occur after BUSY is observed to have been released.

(This patch primarily removes bogus 'read interrupt arrived early' warnings
on the console for things like CF card IDE adapters and other badly designed
IDE devices).

/*-
 * Copyright (c) 1998,1999,2000,2001,2002 Søren Schmidt <sos@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer,
 *    without modification, immediately at the beginning of the file.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * $FreeBSD: src/sys/dev/ata/ata-disk.c,v 1.60.2.24 2003/01/30 07:19:59 sos Exp $
 * $DragonFly: src/sys/dev/disk/ata/ata-disk.c,v 1.9 2003/12/29 03:42:43 dillon Exp $
 */

#include "opt_ata.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/ata.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/buf.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/disk.h>
#include <sys/devicestat.h>
#include <sys/cons.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <vm/vm.h>
#include <vm/pmap.h>
#include <machine/md_var.h>
#include <machine/bus.h>
#include <machine/clock.h>
#include <sys/rman.h>
#include "ata-all.h"
#include "ata-disk.h"
#include "ata-raid.h"
#include <sys/proc.h>
#include <sys/buf2.h>

/* device structures */
static d_open_t		adopen;
static d_close_t	adclose;
static d_strategy_t	adstrategy;
static d_dump_t		addump;

static struct cdevsw ad_cdevsw = {
	/* name */	"ad",
	/* maj */	116,
	/* flags */	D_DISK,
	/* port */      NULL,
	/* autoq */	0,

	/* open */	adopen,
	/* close */	adclose,
	/* read */	physread,
	/* write */	physwrite,
	/* ioctl */	noioctl,
	/* poll */	nopoll,
	/* mmap */	nommap,
	/* strategy */	adstrategy,
	/* dump */	addump,
	/* psize */	nopsize
};

/* prototypes */
static void ad_invalidatequeue(struct ad_softc *, struct ad_request *);
static int ad_tagsupported(struct ad_softc *);
static void ad_timeout(struct ad_request *);
static void ad_free(struct ad_request *);
static int ad_version(u_int16_t);

/* misc defines */
#define AD_MAX_RETRIES	3

/* internal vars */
static u_int32_t adp_lun_map = 0;
static int ata_dma = 1;
static int ata_wc = 1;
static int ata_tags = 0; 
TUNABLE_INT("hw.ata.ata_dma", &ata_dma);
TUNABLE_INT("hw.ata.wc", &ata_wc);
TUNABLE_INT("hw.ata.tags", &ata_tags);
static MALLOC_DEFINE(M_AD, "AD driver", "ATA disk driver");

/* sysctl vars */
SYSCTL_DECL(_hw_ata);
SYSCTL_INT(_hw_ata, OID_AUTO, ata_dma, CTLFLAG_RD, &ata_dma, 0,
	   "ATA disk DMA mode control");
SYSCTL_INT(_hw_ata, OID_AUTO, wc, CTLFLAG_RD, &ata_wc, 0,
	   "ATA disk write caching");
SYSCTL_INT(_hw_ata, OID_AUTO, tags, CTLFLAG_RD, &ata_tags, 0,
	   "ATA disk tagged queuing support");

void
ad_attach(struct ata_device *atadev)
{
    struct ad_softc *adp;
    dev_t dev;

    if (!(adp = malloc(sizeof(struct ad_softc), M_AD, M_WAITOK | M_ZERO))) {
	ata_prtdev(atadev, "failed to allocate driver storage\n");
	return;
    }

    KKASSERT(atadev->channel->req_mpipe.max_count != 0);

    adp->device = atadev;
#ifdef ATA_STATIC_ID
    adp->lun = (device_get_unit(atadev->channel->dev)<<1)+ATA_DEV(atadev->unit);
#else
    adp->lun = ata_get_lun(&adp_lun_map);
#endif
    ata_set_name(atadev, "ad", adp->lun);
    adp->heads = atadev->param->heads;
    adp->sectors = atadev->param->sectors;
    adp->total_secs = atadev->param->cylinders * adp->heads * adp->sectors;	
    bufq_init(&adp->queue);

    /* does this device need oldstyle CHS addressing */
    if (!ad_version(atadev->param->version_major) || 
	!(atadev->param->atavalid & ATA_FLAG_54_58) || !atadev->param->lba_size)
	adp->flags |= AD_F_CHS_USED;

    /* use the 28bit LBA size if valid */
    if (atadev->param->cylinders == 16383 &&
	adp->total_secs < atadev->param->lba_size)
	adp->total_secs = atadev->param->lba_size;

    /* use the 48bit LBA size if valid */
    if (atadev->param->support.address48 &&
	atadev->param->lba_size48 > 268435455)
	adp->total_secs = atadev->param->lba_size48;
    
    ATA_SLEEPLOCK_CH(atadev->channel, ATA_CONTROL);
    /* use multiple sectors/interrupt if device supports it */
    adp->transfersize = DEV_BSIZE;
    if (ad_version(atadev->param->version_major)) {
	int secsperint = max(1, min(atadev->param->sectors_intr, 16));

	if (!ata_command(atadev, ATA_C_SET_MULTI, 0, secsperint,
			 0, ATA_WAIT_INTR) && !ata_wait(atadev, 0))
	adp->transfersize *= secsperint;
    }

    /* enable read caching if not default on device */
    if (ata_command(atadev, ATA_C_SETFEATURES,
		    0, 0, ATA_C_F_ENAB_RCACHE, ATA_WAIT_INTR))
	ata_prtdev(atadev, "enabling readahead cache failed\n");

    /* enable write caching if allowed and not default on device */
    if (ata_wc || (ata_tags && ad_tagsupported(adp))) {
	if (ata_command(atadev, ATA_C_SETFEATURES,
			0, 0, ATA_C_F_ENAB_WCACHE, ATA_WAIT_INTR))
	    ata_prtdev(atadev, "enabling write cache failed\n");
    }
    else {
	if (ata_command(atadev, ATA_C_SETFEATURES,
			0, 0, ATA_C_F_DIS_WCACHE, ATA_WAIT_INTR))
	    ata_prtdev(atadev, "disabling write cache failed\n");
    }

    /* use DMA if allowed and if drive/controller supports it */
    if (ata_dma)
	ata_dmainit(atadev->channel, atadev->unit, ata_pmode(atadev->param), 
		    ata_wmode(atadev->param), ata_umode(atadev->param));
    else
	ata_dmainit(atadev->channel, atadev->unit,
		    ata_pmode(atadev->param), -1, -1);

    /* use tagged queueing if allowed and supported */
    if (ata_tags && ad_tagsupported(adp)) {
	adp->num_tags = atadev->param->queuelen;
	adp->flags |= AD_F_TAG_ENABLED;
	adp->device->channel->flags |= ATA_QUEUED;
	if (ata_command(atadev, ATA_C_SETFEATURES,
			0, 0, ATA_C_F_DIS_RELIRQ, ATA_WAIT_INTR))
	    ata_prtdev(atadev, "disabling release interrupt failed\n");
	if (ata_command(atadev, ATA_C_SETFEATURES,
			0, 0, ATA_C_F_DIS_SRVIRQ, ATA_WAIT_INTR))
	    ata_prtdev(atadev, "disabling service interrupt failed\n");
    }

    ATA_UNLOCK_CH(atadev->channel);

    devstat_add_entry(&adp->stats, "ad", adp->lun, DEV_BSIZE,
		      DEVSTAT_NO_ORDERED_TAGS,
		      DEVSTAT_TYPE_DIRECT | DEVSTAT_TYPE_IF_IDE,
		      DEVSTAT_PRIORITY_DISK);

    dev = disk_create(adp->lun, &adp->disk, 0, &ad_cdevsw);
    dev->si_drv1 = adp;
    dev->si_iosize_max = 256 * DEV_BSIZE;
    adp->dev = dev;

    /* construct the disklabel */
    bzero(&adp->disk.d_label, sizeof(struct disklabel));
    adp->disk.d_label.d_secsize = DEV_BSIZE;
    adp->disk.d_label.d_nsectors = adp->sectors;
    adp->disk.d_label.d_ntracks = adp->heads;
    adp->disk.d_label.d_ncylinders = adp->total_secs/(adp->heads*adp->sectors);
    adp->disk.d_label.d_secpercyl = adp->sectors * adp->heads;
    adp->disk.d_label.d_secperunit = adp->total_secs;

    atadev->driver = adp;
    atadev->flags = 0;

    /* if this disk belongs to an ATA RAID dont print the probe */
    if (ata_raiddisk_attach(adp))
	adp->flags |= AD_F_RAID_SUBDISK;
    else {
	if (atadev->driver) {
	    ad_print(adp);
	    ata_enclosure_print(atadev);
	}
    }
}

void
ad_detach(struct ata_device *atadev, int flush) /* get rid of flush XXX SOS */
{
    struct ad_softc *adp = atadev->driver;
    struct ad_request *request;
    struct buf *bp;

    atadev->flags |= ATA_D_DETACHING;
    ata_prtdev(atadev, "removed from configuration\n");
    ad_invalidatequeue(adp, NULL);
    TAILQ_FOREACH(request, &atadev->channel->ata_queue, chain) {
	if (request->softc != adp)
	    continue;
	TAILQ_REMOVE(&atadev->channel->ata_queue, request, chain);
	request->bp->b_error = ENXIO;
	request->bp->b_flags |= B_ERROR;
	biodone(request->bp);
	ad_free(request);
    }
    while ((bp = bufq_first(&adp->queue))) {
	bufq_remove(&adp->queue, bp); 
	bp->b_error = ENXIO;
	bp->b_flags |= B_ERROR;
	biodone(bp);
    }
    disk_invalidate(&adp->disk);
    devstat_remove_entry(&adp->stats);
    disk_destroy(&adp->disk);
    if (flush) {
	if (ata_command(atadev, ATA_C_FLUSHCACHE, 0, 0, 0, ATA_WAIT_READY))
	    ata_prtdev(atadev, "flushing cache on detach failed\n");
    }
    if (adp->flags & AD_F_RAID_SUBDISK)
	ata_raiddisk_detach(adp);
    ata_free_name(atadev);
    ata_free_lun(&adp_lun_map, adp->lun);
    atadev->driver = NULL;
    atadev->flags = 0;
    free(adp, M_AD);
}

static int
adopen(dev_t dev, int flags, int fmt, struct thread *td)
{
    struct ad_softc *adp = dev->si_drv1;

    if (adp->flags & AD_F_RAID_SUBDISK)
	return EBUSY;
    return 0;
}

static int
adclose(dev_t dev, int flags, int fmt, struct thread *td)
{
    struct ad_softc *adp = dev->si_drv1;

    ATA_SLEEPLOCK_CH(adp->device->channel, ATA_CONTROL);
    if (ata_command(adp->device, ATA_C_FLUSHCACHE, 0, 0, 0, ATA_WAIT_READY))
	ata_prtdev(adp->device, "flushing cache on close failed\n");
    ATA_UNLOCK_CH(adp->device->channel);
    return 0;
}

static void 
adstrategy(struct buf *bp)
{
    struct ad_softc *adp = bp->b_dev->si_drv1;
    int s;

    if (adp->device->flags & ATA_D_DETACHING) {
	bp->b_error = ENXIO;
	bp->b_flags |= B_ERROR;
	biodone(bp);
	return;
    }
    s = splbio();
    bufqdisksort(&adp->queue, bp);
    splx(s);
    ata_start(adp->device->channel);
}

int
addump(dev_t dev)
{
    struct ad_softc *adp = dev->si_drv1;
    struct ad_request request;
    u_int count, blkno, secsize;
    vm_offset_t addr = 0;
    long blkcnt;
    int dumppages = MAXDUMPPGS;
    int error;
    int i;

    if ((error = disk_dumpcheck(dev, &count, &blkno, &secsize)))
	return error;
	
    if (!adp)
	return ENXIO;

    /* force PIO mode for dumps */
    adp->device->mode = ATA_PIO;
    ata_reinit(adp->device->channel);

    blkcnt = howmany(PAGE_SIZE, secsize);

    while (count > 0) {
	caddr_t va = NULL;
	DELAY(1000);

	if ((count / blkcnt) < dumppages)
	    dumppages = count / blkcnt;

	for (i = 0; i < dumppages; ++i) {
	    vm_offset_t a = addr + (i * PAGE_SIZE);
	    if (is_physical_memory(a))
		va = pmap_kenter_temporary(trunc_page(a), i);
	    else
		va = pmap_kenter_temporary(trunc_page(0), i);
	}

	bzero(&request, sizeof(struct ad_request));
	request.softc = adp;
	request.blockaddr = blkno;
	request.bytecount = PAGE_SIZE * dumppages;
	request.data = va;

	while (request.bytecount > 0) {
	    ad_transfer(&request);
	    if (request.flags & ADR_F_ERROR)
		return EIO;
	    request.donecount += request.currentsize;
	    request.bytecount -= request.currentsize;
	    DELAY(20);
	}

	if (dumpstatus(addr, (off_t)count * DEV_BSIZE) < 0)
	    return EINTR;

	blkno += blkcnt * dumppages;
	count -= blkcnt * dumppages;
	addr += PAGE_SIZE * dumppages;
    }

    if (ata_wait(adp->device, ATA_S_READY | ATA_S_DSC) < 0)
	ata_prtdev(adp->device, "timeout waiting for final ready\n");
    return 0;
}

void
ad_start(struct ata_device *atadev)
{
    struct ad_softc *adp = atadev->driver;
    struct buf *bp = bufq_first(&adp->queue);
    struct ad_request *request;
    int tag = 0;

    if (!bp)
	return;

    /* if tagged queueing enabled get next free tag */
    if (adp->flags & AD_F_TAG_ENABLED) {
	while (tag <= adp->num_tags && adp->tags[tag])
	    tag++;
	if (tag > adp->num_tags )
	    return;
    }

    /*
     * Allocate a request.  The allocation can only fail if the pipeline
     * is full, in which case the request will be picked up later when
     * ad_start() is called after another request completes.
     */
    request = mpipe_alloc(&atadev->channel->req_mpipe, M_NOWAIT|M_ZERO);
    if (request == NULL) {
	ata_prtdev(atadev, "pipeline full allocating request in ad_start\n");
	return;
    }

    /* setup request */
    request->softc = adp;
    request->bp = bp;
    request->blockaddr = bp->b_pblkno;
    request->bytecount = bp->b_bcount;
    request->data = bp->b_data;
    request->tag = tag;
    if (bp->b_flags & B_READ) 
	request->flags |= ADR_F_READ;
    if (adp->device->mode >= ATA_DMA) {
	request->dmatab = ata_dmaalloc(atadev->channel, atadev->unit, M_NOWAIT);
	if (request->dmatab == NULL) {
	    mpipe_free(&atadev->channel->req_mpipe, request);
	    ata_prtdev(atadev, "pipeline full allocated dmabuf in ad_start\n");
	    /* do not revert to PIO, wait for ad_start after I/O completion */
	    return;
	}
    }

    /* insert in tag array */
    adp->tags[tag] = request;

    /* remove from drive queue */
    bufq_remove(&adp->queue, bp); 

    /* link onto controller queue */
    TAILQ_INSERT_TAIL(&atadev->channel->ata_queue, request, chain);
}

int
ad_transfer(struct ad_request *request)
{
    struct ad_softc *adp;
    u_int64_t lba;
    u_int32_t count, max_count;
    u_int8_t cmd;
    int flags = ATA_IMMEDIATE;

    /* get request params */
    adp = request->softc;

    /* calculate transfer details */
    lba = request->blockaddr + (request->donecount / DEV_BSIZE);
   
    if (request->donecount == 0) {

	/* start timeout for this transfer */
	if (dumping)
	    request->timeout_handle.callout = NULL;
	else
	    request->timeout_handle = 
		timeout((timeout_t*)ad_timeout, request, 10 * hz);

	/* setup transfer parameters */
	count = howmany(request->bytecount, DEV_BSIZE);
	max_count = adp->device->param->support.address48 ? 65536 : 256;
	if (count > max_count) {
	    ata_prtdev(adp->device,
		       "count %d size transfers not supported\n", count);
	    count = max_count;
	}

	if (adp->flags & AD_F_CHS_USED) {
	    int sector = (lba % adp->sectors) + 1;
	    int cylinder = lba / (adp->sectors * adp->heads);
	    int head = (lba % (adp->sectors * adp->heads)) / adp->sectors;

	    lba = (sector&0xff) | ((cylinder&0xffff)<<8) | ((head&0xf)<<24);
	    adp->device->flags |= ATA_D_USE_CHS;
	}

	/* setup first transfer length */
	request->currentsize = min(request->bytecount, adp->transfersize);

	devstat_start_transaction(&adp->stats);

	/* does this drive & transfer work with DMA ? */
	request->flags &= ~ADR_F_DMA_USED;
	if (adp->device->mode >= ATA_DMA &&
	    !ata_dmasetup(adp->device->channel, adp->device->unit,
			  request->dmatab, request->data, request->bytecount)) {
	    request->flags |= ADR_F_DMA_USED;
	    request->currentsize = request->bytecount;

	    /* do we have tags enabled ? */
	    if (adp->flags & AD_F_TAG_ENABLED) {
		cmd = (request->flags & ADR_F_READ) ?
		    ATA_C_READ_DMA_QUEUED : ATA_C_WRITE_DMA_QUEUED;

		if (ata_command(adp->device, cmd, lba,
				request->tag << 3, count, flags)) {
		    ata_prtdev(adp->device, "error executing command");
		    goto transfer_failed;
		}
		if (ata_wait(adp->device, ATA_S_READY)) {
		    ata_prtdev(adp->device, "timeout waiting for READY\n");
		    goto transfer_failed;
		}
		adp->outstanding++;

		/* if ATA bus RELEASE check for SERVICE */
		if (adp->flags & AD_F_TAG_ENABLED &&
		    ATA_INB(adp->device->channel->r_io, ATA_IREASON) &
		    ATA_I_RELEASE)
		    return ad_service(adp, 1);
	    }
	    else {
		cmd = (request->flags & ADR_F_READ) ?
		    ATA_C_READ_DMA : ATA_C_WRITE_DMA;

		if (ata_command(adp->device, cmd, lba, count, 0, flags)) {
		    ata_prtdev(adp->device, "error executing command");
		    goto transfer_failed;
		}
#if 0
		/*
		 * wait for data transfer phase
		 *
		 * well this should be here acording to specs, but older
		 * promise controllers doesn't like it, they lockup!
		 */
		if (ata_wait(adp->device, ATA_S_READY | ATA_S_DRQ)) {
		    ata_prtdev(adp->device, "timeout waiting for data phase\n");
		    goto transfer_failed;
		}
#endif
	    }

	    /* start transfer, return and wait for interrupt */
	    ata_dmastart(adp->device->channel, adp->device->unit,
			 request->dmatab, request->flags & ADR_F_READ);
	    return ATA_OP_CONTINUES;
	}

	/* does this drive support multi sector transfers ? */
	if (request->currentsize > DEV_BSIZE)
	    cmd = request->flags&ADR_F_READ ? ATA_C_READ_MUL : ATA_C_WRITE_MUL;

	/* just plain old single sector transfer */
	else
	    cmd = request->flags&ADR_F_READ ? ATA_C_READ : ATA_C_WRITE;

	if (ata_command(adp->device, cmd, lba, count, 0, flags)){
	    ata_prtdev(adp->device, "error executing command");
	    goto transfer_failed;
	}
    }
   
    /* calculate this transfer length */
    request->currentsize = min(request->bytecount, adp->transfersize);

    /* if this is a PIO read operation, return and wait for interrupt */
    if (request->flags & ADR_F_READ)
	return ATA_OP_CONTINUES;

    /* ready to write PIO data ? */
    if (ata_wait(adp->device, (ATA_S_READY | ATA_S_DSC | ATA_S_DRQ)) < 0) {
	ata_prtdev(adp->device, "timeout waiting for DRQ");
	goto transfer_failed;
    }

    /* output the data */
    if (adp->device->channel->flags & ATA_USE_16BIT)
	ATA_OUTSW(adp->device->channel->r_io, ATA_DATA,
		  (void *)((uintptr_t)request->data + request->donecount),
		  request->currentsize / sizeof(int16_t));
    else
	ATA_OUTSL(adp->device->channel->r_io, ATA_DATA,
		  (void *)((uintptr_t)request->data + request->donecount),
		  request->currentsize / sizeof(int32_t));
    return ATA_OP_CONTINUES;

transfer_failed:
    untimeout((timeout_t *)ad_timeout, request, request->timeout_handle);
    ad_invalidatequeue(adp, request);
    printf(" - resetting\n");

    /* if retries still permit, reinject this request */
    if (request->retries++ < AD_MAX_RETRIES)
	TAILQ_INSERT_HEAD(&adp->device->channel->ata_queue, request, chain);
    else {
	/* retries all used up, return error */
	request->bp->b_error = EIO;
	request->bp->b_flags |= B_ERROR;
	request->bp->b_resid = request->bytecount;
	devstat_end_transaction_buf(&adp->stats, request->bp);
	biodone(request->bp);
	ad_free(request);
    }
    ata_reinit(adp->device->channel);
    return ATA_OP_CONTINUES;
}

int
ad_interrupt(struct ad_request *request)
{
    struct ad_softc *adp = request->softc;
    int dma_stat = 0;

    /* finish DMA transfer */
    if (request->flags & ADR_F_DMA_USED)
	dma_stat = ata_dmadone(adp->device->channel);

    /* do we have a corrected soft error ? */
    if (adp->device->channel->status & ATA_S_CORR)
	diskerr(request->bp, "soft error (ECC corrected)", LOG_PRINTF,
		request->blockaddr + (request->donecount / DEV_BSIZE),
		&adp->disk.d_label);

    /* did any real errors happen ? */
    if ((adp->device->channel->status & ATA_S_ERROR) ||
	(request->flags & ADR_F_DMA_USED && dma_stat & ATA_BMSTAT_ERROR)) {
	adp->device->channel->error =
	    ATA_INB(adp->device->channel->r_io, ATA_ERROR);
	diskerr(request->bp, (adp->device->channel->error & ATA_E_ICRC) ?
		"UDMA ICRC error" : "hard error", LOG_PRINTF,
		request->blockaddr + (request->donecount / DEV_BSIZE),
		&adp->disk.d_label);

	/* if this is a UDMA CRC error, reinject request */
	if (request->flags & ADR_F_DMA_USED &&
	    adp->device->channel->error & ATA_E_ICRC) {
	    untimeout((timeout_t *)ad_timeout, request,request->timeout_handle);
	    ad_invalidatequeue(adp, request);

	    if (request->retries++ < AD_MAX_RETRIES)
		printf(" retrying\n");
	    else {
		ata_dmainit(adp->device->channel, adp->device->unit, 
			    ata_pmode(adp->device->param), -1, -1);
		printf(" falling back to PIO mode\n");
	    }
	    TAILQ_INSERT_HEAD(&adp->device->channel->ata_queue, request, chain);
	    return ATA_OP_FINISHED;
	}

	/* if using DMA, try once again in PIO mode */
	if (request->flags & ADR_F_DMA_USED) {
	    untimeout((timeout_t *)ad_timeout, request,request->timeout_handle);
	    ad_invalidatequeue(adp, request);
	    ata_dmainit(adp->device->channel, adp->device->unit,
			ata_pmode(adp->device->param), -1, -1);
	    request->flags |= ADR_F_FORCE_PIO;
	    printf(" trying PIO mode\n");
	    TAILQ_INSERT_HEAD(&adp->device->channel->ata_queue, request, chain);
	    return ATA_OP_FINISHED;
	}

	request->flags |= ADR_F_ERROR;
	printf(" status=%02x error=%02x\n", 
	       adp->device->channel->status, adp->device->channel->error);
    }

    /* if we arrived here with forced PIO mode, DMA doesn't work right */
    if (request->flags & ADR_F_FORCE_PIO && !(request->flags & ADR_F_ERROR))
	ata_prtdev(adp->device, "DMA problem fallback to PIO mode\n");

    /* if this was a PIO read operation, get the data */
    if (!(request->flags & ADR_F_DMA_USED) &&
	(request->flags & (ADR_F_READ | ADR_F_ERROR)) == ADR_F_READ) {

	/* ready to receive data? */
	if ((adp->device->channel->status & ATA_S_READY) == 0) {
	    ata_prtdev(adp->device, "read interrupt arrived early %08x\n",
		(int)adp->device->channel->status);
	}

	if (ata_wait(adp->device, (ATA_S_READY | ATA_S_DSC | ATA_S_DRQ)) != 0) {
	    ata_prtdev(adp->device, "read error detected (too) late");
	    request->flags |= ADR_F_ERROR;
	}
	else {
	    /* data ready, read in */
	    if (adp->device->channel->flags & ATA_USE_16BIT)
		ATA_INSW(adp->device->channel->r_io, ATA_DATA,
			 (void*)((uintptr_t)request->data + request->donecount),
			 request->currentsize / sizeof(int16_t));
	    else
		ATA_INSL(adp->device->channel->r_io, ATA_DATA,
			 (void*)((uintptr_t)request->data + request->donecount),
			 request->currentsize / sizeof(int32_t));
	}
    }

    /* finish up transfer */
    if (request->flags & ADR_F_ERROR) {
	request->bp->b_error = EIO;
	request->bp->b_flags |= B_ERROR;
    } 
    else {
	request->bytecount -= request->currentsize;
	request->donecount += request->currentsize;
	if (request->bytecount > 0) {
	    ad_transfer(request);
	    return ATA_OP_CONTINUES;
	}
    }

    /* disarm timeout for this transfer */
    untimeout((timeout_t *)ad_timeout, request, request->timeout_handle);

    request->bp->b_resid = request->bytecount;

    devstat_end_transaction_buf(&adp->stats, request->bp);
    biodone(request->bp);
    ad_free(request);
    adp->outstanding--;

    /* check for SERVICE (tagged operations only) */
    return ad_service(adp, 1);
}

int
ad_service(struct ad_softc *adp, int change)
{
    /* do we have to check the other device on this channel ? */
    if (adp->device->channel->flags & ATA_QUEUED && change) {
	int device = adp->device->unit;

	if (adp->device->unit == ATA_MASTER) {
	    if ((adp->device->channel->devices & ATA_ATA_SLAVE) &&
		(adp->device->channel->device[SLAVE].driver) &&
		((struct ad_softc *) (adp->device->channel->
		 device[SLAVE].driver))->flags & AD_F_TAG_ENABLED)
		device = ATA_SLAVE;
	}
	else {
	    if ((adp->device->channel->devices & ATA_ATA_MASTER) &&
		(adp->device->channel->device[MASTER].driver) &&
		((struct ad_softc *) (adp->device->channel->
		 device[MASTER].driver))->flags & AD_F_TAG_ENABLED)
		device = ATA_MASTER;
	}
	if (device != adp->device->unit &&
	    ((struct ad_softc *)
	     (adp->device->channel->
	      device[ATA_DEV(device)].driver))->outstanding > 0) {
	    ATA_OUTB(adp->device->channel->r_io, ATA_DRIVE, ATA_D_IBM | device);
	    adp = adp->device->channel->device[ATA_DEV(device)].driver;
	    DELAY(1);
	}
    }
    adp->device->channel->status =
	ATA_INB(adp->device->channel->r_altio, ATA_ALTSTAT);
 
    /* do we have a SERVICE request from the drive ? */
    if (adp->flags & AD_F_TAG_ENABLED &&
	adp->outstanding > 0 &&
	adp->device->channel->status & ATA_S_SERVICE) {
	struct ad_request *request;
	int tag;

	/* check for error */
	if (adp->device->channel->status & ATA_S_ERROR) {
	    ata_prtdev(adp->device, "Oops! controller says s=0x%02x e=0x%02x\n",
		       adp->device->channel->status,
		       adp->device->channel->error);
	    ad_invalidatequeue(adp, NULL);
	    return ATA_OP_FINISHED;
	}

	/* issue SERVICE cmd */
	if (ata_command(adp->device, ATA_C_SERVICE, 0, 0, 0, ATA_IMMEDIATE)) {
	    ata_prtdev(adp->device, "problem executing SERVICE cmd\n");
	    ad_invalidatequeue(adp, NULL);
	    return ATA_OP_FINISHED;
	}

	/* setup the transfer environment when ready */
	if (ata_wait(adp->device, ATA_S_READY)) {
	    ata_prtdev(adp->device, "SERVICE timeout tag=%d s=%02x e=%02x\n",
		       ATA_INB(adp->device->channel->r_io, ATA_COUNT) >> 3,
		       adp->device->channel->status,
		       adp->device->channel->error);
	    ad_invalidatequeue(adp, NULL);
	    return ATA_OP_FINISHED;
	}
	tag = ATA_INB(adp->device->channel->r_io, ATA_COUNT) >> 3;
	if (!(request = adp->tags[tag])) {
	    ata_prtdev(adp->device, "no request for tag=%d\n", tag);	
	    ad_invalidatequeue(adp, NULL);
	    return ATA_OP_FINISHED;
	}
	ATA_FORCELOCK_CH(adp->device->channel, ATA_ACTIVE_ATA);
	adp->device->channel->running = request;
	request->serv++;

	/* start DMA transfer when ready */
	if (ata_wait(adp->device, ATA_S_READY | ATA_S_DRQ)) {
	    ata_prtdev(adp->device, "timeout starting DMA s=%02x e=%02x\n",
		       adp->device->channel->status,
		       adp->device->channel->error);
	    ad_invalidatequeue(adp, NULL);
	    return ATA_OP_FINISHED;
	}
	ata_dmastart(adp->device->channel, adp->device->unit,
		     request->dmatab, request->flags & ADR_F_READ);
	return ATA_OP_CONTINUES;
    }
    return ATA_OP_FINISHED;
}

static void
ad_free(struct ad_request *request)
{
    int s = splbio();

    if (request->dmatab)
	ata_dmafree(request->softc->device->channel, request->dmatab);
    request->softc->tags[request->tag] = NULL;
    mpipe_free(&request->softc->device->channel->req_mpipe, request);
    splx(s);
}

static void
ad_invalidatequeue(struct ad_softc *adp, struct ad_request *request)
{
    /* if tags used invalidate all other tagged transfers */
    if (adp->flags & AD_F_TAG_ENABLED) {
	struct ad_request *tmpreq;
	int tag;

	ata_prtdev(adp->device, "invalidating queued requests\n");
	for (tag = 0; tag <= adp->num_tags; tag++) {
	    tmpreq = adp->tags[tag];
	    adp->tags[tag] = NULL;
	    if (tmpreq == request || tmpreq == NULL)
		continue;
	    untimeout((timeout_t *)ad_timeout, tmpreq, tmpreq->timeout_handle);
	    TAILQ_INSERT_HEAD(&adp->device->channel->ata_queue, tmpreq, chain);
	}
	if (ata_command(adp->device, ATA_C_NOP,
			0, 0, ATA_C_F_FLUSHQUEUE, ATA_WAIT_READY))
	    ata_prtdev(adp->device, "flush queue failed\n");
	adp->outstanding = 0;
    }
}

static int
ad_tagsupported(struct ad_softc *adp)
{
    const char *good[] = {"IBM-DPTA", "IBM-DTLA", NULL};
    int i = 0;

    switch (adp->device->channel->chiptype) {
    case 0x4d33105a: /* Promises before TX2 doesn't work with tagged queuing */
    case 0x4d38105a:
    case 0x0d30105a:
    case 0x4d30105a:  
	return 0;
    }

    /* check that drive does DMA, has tags enabled, and is one we know works */
    if (adp->device->mode >= ATA_DMA && adp->device->param->support.queued && 
	adp->device->param->enabled.queued) {
	while (good[i] != NULL) {
	    if (!strncmp(adp->device->param->model, good[i], strlen(good[i])))
		return 1;
	    i++;
	}
	/* 
	 * check IBM's new obscure way of naming drives 
	 * we want "IC" (IBM CORP) and "AT" or "AV" (ATA interface)
	 * but doesn't care about the other info (size, capacity etc)
	 */
	if (!strncmp(adp->device->param->model, "IC", 2) &&
	    (!strncmp(adp->device->param->model + 8, "AT", 2) ||
	     !strncmp(adp->device->param->model + 8, "AV", 2)))
		return 1;
    }
    return 0;
}

static void
ad_timeout(struct ad_request *request)
{
    struct ad_softc *adp = request->softc;

    adp->device->channel->running = NULL;
    ata_prtdev(adp->device, "%s command timeout tag=%d serv=%d - resetting\n",
	       (request->flags & ADR_F_READ) ? "READ" : "WRITE",
	       request->tag, request->serv);

    if (request->flags & ADR_F_DMA_USED) {
	ata_dmadone(adp->device->channel);
	ad_invalidatequeue(adp, request);
	if (request->retries == AD_MAX_RETRIES) {
	    ata_dmainit(adp->device->channel, adp->device->unit,
			ata_pmode(adp->device->param), -1, -1);
	    ata_prtdev(adp->device, "trying fallback to PIO mode\n");
	    request->retries = 0;
	}
    }

    /* if retries still permit, reinject this request */
    if (request->retries++ < AD_MAX_RETRIES) {
	TAILQ_INSERT_HEAD(&adp->device->channel->ata_queue, request, chain);
    }
    else {
	/* retries all used up, return error */
	request->bp->b_error = EIO;
	request->bp->b_flags |= B_ERROR;
	devstat_end_transaction_buf(&adp->stats, request->bp);
	biodone(request->bp);
	ad_free(request);
    }
    ata_reinit(adp->device->channel);
}

void
ad_reinit(struct ata_device *atadev)
{
    struct ad_softc *adp = atadev->driver;

    /* reinit disk parameters */
    ad_invalidatequeue(atadev->driver, NULL);
    ata_command(atadev, ATA_C_SET_MULTI, 0,
		adp->transfersize / DEV_BSIZE, 0, ATA_WAIT_READY);
    if (adp->device->mode >= ATA_DMA)
	ata_dmainit(atadev->channel, atadev->unit,
		    ata_pmode(adp->device->param),
		    ata_wmode(adp->device->param),
		    ata_umode(adp->device->param));
    else
	ata_dmainit(atadev->channel, atadev->unit,
		    ata_pmode(adp->device->param), -1, -1);
}

void
ad_print(struct ad_softc *adp) 
{
    if (bootverbose) {
	ata_prtdev(adp->device, "<%.40s/%.8s> ATA-%d disk at ata%d-%s\n", 
		   adp->device->param->model, adp->device->param->revision,
		   ad_version(adp->device->param->version_major), 
		   device_get_unit(adp->device->channel->dev),
		   (adp->device->unit == ATA_MASTER) ? "master" : "slave");

	ata_prtdev(adp->device,
		   "%lluMB (%llu sectors), %llu C, %u H, %u S, %u B\n",
		   (unsigned long long)(adp->total_secs /
		   ((1024L*1024L)/DEV_BSIZE)),
		   (unsigned long long) adp->total_secs,
		   (unsigned long long) (adp->total_secs /
		    (adp->heads * adp->sectors)),
		   adp->heads, adp->sectors, DEV_BSIZE);

	ata_prtdev(adp->device, "%d secs/int, %d depth queue, %s%s\n", 
		   adp->transfersize / DEV_BSIZE, adp->num_tags + 1,
		   (adp->flags & AD_F_TAG_ENABLED) ? "tagged " : "",
		   ata_mode2str(adp->device->mode));

	ata_prtdev(adp->device, "piomode=%d dmamode=%d udmamode=%d cblid=%d\n",
		   ata_pmode(adp->device->param), ata_wmode(adp->device->param),
		   ata_umode(adp->device->param), 
		   adp->device->param->hwres_cblid);

    }
    else
	ata_prtdev(adp->device,"%lluMB <%.40s> [%lld/%d/%d] at ata%d-%s %s%s\n",
		   (unsigned long long)(adp->total_secs /
		   ((1024L * 1024L) / DEV_BSIZE)),
		   adp->device->param->model,
		   (unsigned long long)(adp->total_secs /
		    (adp->heads*adp->sectors)),
		   adp->heads, adp->sectors,
		   device_get_unit(adp->device->channel->dev),
		   (adp->device->unit == ATA_MASTER) ? "master" : "slave",
		   (adp->flags & AD_F_TAG_ENABLED) ? "tagged " : "",
		   ata_mode2str(adp->device->mode));
}

static int
ad_version(u_int16_t version)
{
    int bit;

    if (version == 0xffff)
	return 0;
    for (bit = 15; bit >= 0; bit--)
	if (version & (1<<bit))
	    return bit;
    return 0;
}