root/sys/dev/ahci/ahci.c
/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2009-2012 Alexander Motin <mav@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.
 *
 * 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/param.h>
#include <sys/module.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/endian.h>
#include <sys/malloc.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sbuf.h>
#include <sys/stdarg.h>
#include <sys/sysctl.h>
#include <machine/resource.h>
#include <machine/bus.h>
#include <sys/rman.h>
#include "ahci.h"

#include <cam/cam.h>
#include <cam/cam_ccb.h>
#include <cam/cam_sim.h>
#include <cam/cam_xpt_sim.h>
#include <cam/cam_debug.h>

/* local prototypes */
static void ahci_intr(void *data);
static void ahci_intr_one(void *data);
static void ahci_intr_one_edge(void *data);
static int ahci_ch_init(device_t dev);
static int ahci_ch_deinit(device_t dev);
static int ahci_ch_suspend(device_t dev);
static int ahci_ch_resume(device_t dev);
static void ahci_ch_pm(void *arg);
static void ahci_ch_intr(void *arg);
static void ahci_ch_intr_direct(void *arg);
static void ahci_ch_intr_main(struct ahci_channel *ch, uint32_t istatus);
static void ahci_begin_transaction(struct ahci_channel *ch, union ccb *ccb);
static void ahci_dmasetprd(void *arg, bus_dma_segment_t *segs, int nsegs, int error);
static void ahci_execute_transaction(struct ahci_slot *slot);
static void ahci_timeout(void *arg);
static void ahci_end_transaction(struct ahci_slot *slot, enum ahci_err_type et);
static int ahci_setup_fis(struct ahci_channel *ch, struct ahci_cmd_tab *ctp, union ccb *ccb, int tag);
static void ahci_dmainit(device_t dev);
static void ahci_dmasetupc_cb(void *xsc, bus_dma_segment_t *segs, int nsegs, int error);
static void ahci_dmafini(device_t dev);
static void ahci_slotsalloc(device_t dev);
static void ahci_slotsfree(device_t dev);
static void ahci_reset(struct ahci_channel *ch);
static void ahci_start(struct ahci_channel *ch, int fbs);
static void ahci_stop(struct ahci_channel *ch);
static void ahci_clo(struct ahci_channel *ch);
static void ahci_start_fr(struct ahci_channel *ch);
static void ahci_stop_fr(struct ahci_channel *ch);
static int ahci_phy_check_events(struct ahci_channel *ch, u_int32_t serr);
static uint32_t ahci_ch_detval(struct ahci_channel *ch, uint32_t val);

static int ahci_sata_connect(struct ahci_channel *ch);
static int ahci_sata_phy_reset(struct ahci_channel *ch);
static int ahci_wait_ready(struct ahci_channel *ch, int t, int t0);

static void ahci_issue_recovery(struct ahci_channel *ch);
static void ahci_process_read_log(struct ahci_channel *ch, union ccb *ccb);
static void ahci_process_request_sense(struct ahci_channel *ch, union ccb *ccb);

static void ahciaction(struct cam_sim *sim, union ccb *ccb);
static void ahcipoll(struct cam_sim *sim);

static MALLOC_DEFINE(M_AHCI, "AHCI driver", "AHCI driver data buffers");

#define recovery_type           spriv_field0
#define RECOVERY_NONE           0
#define RECOVERY_READ_LOG       1
#define RECOVERY_REQUEST_SENSE  2
#define recovery_slot           spriv_field1

static uint32_t
ahci_ch_detval(struct ahci_channel *ch, uint32_t val)
{

        return ch->disablephy ? ATA_SC_DET_DISABLE : val;
}

int
ahci_ctlr_setup(device_t dev)
{
        struct ahci_controller *ctlr = device_get_softc(dev);
        /* Clear interrupts */
        ATA_OUTL(ctlr->r_mem, AHCI_IS, ATA_INL(ctlr->r_mem, AHCI_IS));
        /* Configure CCC */
        if (ctlr->ccc) {
                ATA_OUTL(ctlr->r_mem, AHCI_CCCP, ATA_INL(ctlr->r_mem, AHCI_PI));
                ATA_OUTL(ctlr->r_mem, AHCI_CCCC,
                    (ctlr->ccc << AHCI_CCCC_TV_SHIFT) |
                    (4 << AHCI_CCCC_CC_SHIFT) |
                    AHCI_CCCC_EN);
                ctlr->cccv = (ATA_INL(ctlr->r_mem, AHCI_CCCC) &
                    AHCI_CCCC_INT_MASK) >> AHCI_CCCC_INT_SHIFT;
                if (bootverbose) {
                        device_printf(dev,
                            "CCC with %dms/4cmd enabled on vector %d\n",
                            ctlr->ccc, ctlr->cccv);
                }
        }
        /* Enable AHCI interrupts */
        ATA_OUTL(ctlr->r_mem, AHCI_GHC,
            ATA_INL(ctlr->r_mem, AHCI_GHC) | AHCI_GHC_IE);
        return (0);
}

int
ahci_ctlr_reset(device_t dev)
{
        struct ahci_controller *ctlr = device_get_softc(dev);
        uint32_t v;
        int timeout;

        /* BIOS/OS Handoff */
        if ((ATA_INL(ctlr->r_mem, AHCI_VS) >= 0x00010200) &&
            (ATA_INL(ctlr->r_mem, AHCI_CAP2) & AHCI_CAP2_BOH) &&
            ((v = ATA_INL(ctlr->r_mem, AHCI_BOHC)) & AHCI_BOHC_OOS) == 0) {
                /* Request OS ownership. */
                ATA_OUTL(ctlr->r_mem, AHCI_BOHC, v | AHCI_BOHC_OOS);

                /* Wait up to 2s for BIOS ownership release. */
                for (timeout = 0; timeout < 80; timeout++) {
                        DELAY(25000);
                        v = ATA_INL(ctlr->r_mem, AHCI_BOHC);
                        if ((v & AHCI_BOHC_BOS) == 0)
                                break;
                        if ((v & AHCI_BOHC_BB) == 0)
                                break;
                }
        }

        /* Enable AHCI mode */
        ATA_OUTL(ctlr->r_mem, AHCI_GHC, AHCI_GHC_AE);
        /* Reset AHCI controller */
        ATA_OUTL(ctlr->r_mem, AHCI_GHC, AHCI_GHC_AE|AHCI_GHC_HR);
        for (timeout = 1000; timeout > 0; timeout--) {
                DELAY(1000);
                if ((ATA_INL(ctlr->r_mem, AHCI_GHC) & AHCI_GHC_HR) == 0)
                        break;
        }
        if (timeout == 0) {
                device_printf(dev, "AHCI controller reset failure\n");
                return (ENXIO);
        }
        /* Reenable AHCI mode */
        ATA_OUTL(ctlr->r_mem, AHCI_GHC, AHCI_GHC_AE);

        if (ctlr->quirks & AHCI_Q_RESTORE_CAP) {
                /*
                 * Restore capability field.
                 * This is write to a read-only register to restore its state.
                 * On fully standard-compliant hardware this is not needed and
                 * this operation shall not take place. See ahci_pci.c for
                 * platforms using this quirk.
                 */
                ATA_OUTL(ctlr->r_mem, AHCI_CAP, ctlr->caps);
        }

        return (0);
}

int
ahci_attach(device_t dev)
{
        struct ahci_controller *ctlr = device_get_softc(dev);
        int error, i, speed, unit;
        uint32_t u, version;
        device_t child;

        ctlr->dev = dev;
        ctlr->ccc = 0;
        resource_int_value(device_get_name(dev),
            device_get_unit(dev), "ccc", &ctlr->ccc);
        mtx_init(&ctlr->ch_mtx, "AHCI channels lock", NULL, MTX_DEF);

        /* Setup our own memory management for channels. */
        ctlr->sc_iomem.rm_start = rman_get_start(ctlr->r_mem);
        ctlr->sc_iomem.rm_end = rman_get_end(ctlr->r_mem);
        ctlr->sc_iomem.rm_type = RMAN_ARRAY;
        ctlr->sc_iomem.rm_descr = "I/O memory addresses";
        if ((error = rman_init(&ctlr->sc_iomem)) != 0) {
                ahci_free_mem(dev);
                return (error);
        }
        if ((error = rman_manage_region(&ctlr->sc_iomem,
            rman_get_start(ctlr->r_mem), rman_get_end(ctlr->r_mem))) != 0) {
                ahci_free_mem(dev);
                rman_fini(&ctlr->sc_iomem);
                return (error);
        }
        /* Get the HW capabilities */
        version = ATA_INL(ctlr->r_mem, AHCI_VS);
        ctlr->caps = ATA_INL(ctlr->r_mem, AHCI_CAP);
        if (version >= 0x00010200)
                ctlr->caps2 = ATA_INL(ctlr->r_mem, AHCI_CAP2);
        if (ctlr->caps & AHCI_CAP_EMS)
                ctlr->capsem = ATA_INL(ctlr->r_mem, AHCI_EM_CTL);

        if (ctlr->quirks & AHCI_Q_FORCE_PI) {
                /*
                 * Enable ports. 
                 * The spec says that BIOS sets up bits corresponding to
                 * available ports. On platforms where this information
                 * is missing, the driver can define available ports on its own.
                 */
                int nports = (ctlr->caps & AHCI_CAP_NPMASK) + 1;
                int nmask = (1 << nports) - 1;

                ATA_OUTL(ctlr->r_mem, AHCI_PI, nmask);
                device_printf(dev, "Forcing PI to %d ports (mask = %x)\n",
                    nports, nmask);
        }

        ctlr->ichannels = ATA_INL(ctlr->r_mem, AHCI_PI);

        /* Identify and set separate quirks for HBA and RAID f/w Marvells. */
        if ((ctlr->quirks & AHCI_Q_ALTSIG) &&
            (ctlr->caps & AHCI_CAP_SPM) == 0)
                ctlr->quirks |= AHCI_Q_NOBSYRES;

        if (ctlr->quirks & AHCI_Q_1CH) {
                ctlr->caps &= ~AHCI_CAP_NPMASK;
                ctlr->ichannels &= 0x01;
        }
        if (ctlr->quirks & AHCI_Q_2CH) {
                ctlr->caps &= ~AHCI_CAP_NPMASK;
                ctlr->caps |= 1;
                ctlr->ichannels &= 0x03;
        }
        if (ctlr->quirks & AHCI_Q_4CH) {
                ctlr->caps &= ~AHCI_CAP_NPMASK;
                ctlr->caps |= 3;
                ctlr->ichannels &= 0x0f;
        }
        ctlr->channels = MAX(flsl(ctlr->ichannels),
            (ctlr->caps & AHCI_CAP_NPMASK) + 1);
        if (ctlr->quirks & AHCI_Q_NOPMP)
                ctlr->caps &= ~AHCI_CAP_SPM;
        if (ctlr->quirks & AHCI_Q_NONCQ)
                ctlr->caps &= ~AHCI_CAP_SNCQ;
        if ((ctlr->caps & AHCI_CAP_CCCS) == 0)
                ctlr->ccc = 0;
        ctlr->emloc = ATA_INL(ctlr->r_mem, AHCI_EM_LOC);

        /* Create controller-wide DMA tag. */
        if (bus_dma_tag_create(bus_get_dma_tag(dev), 1, 0,
            (ctlr->caps & AHCI_CAP_64BIT) ? BUS_SPACE_MAXADDR :
            BUS_SPACE_MAXADDR_32BIT, BUS_SPACE_MAXADDR, NULL, NULL,
            BUS_SPACE_MAXSIZE, BUS_SPACE_UNRESTRICTED, BUS_SPACE_MAXSIZE,
            ctlr->dma_coherent ? BUS_DMA_COHERENT : 0, NULL, NULL, 
            &ctlr->dma_tag)) {
                ahci_free_mem(dev);
                rman_fini(&ctlr->sc_iomem);
                return (ENXIO);
        }

        ahci_ctlr_setup(dev);

        /* Setup interrupts. */
        if ((error = ahci_setup_interrupt(dev)) != 0) {
                bus_dma_tag_destroy(ctlr->dma_tag);
                ahci_free_mem(dev);
                rman_fini(&ctlr->sc_iomem);
                return (error);
        }

        i = 0;
        for (u = ctlr->ichannels; u != 0; u >>= 1)
                i += (u & 1);
        ctlr->direct = (ctlr->msi && (ctlr->numirqs > 1 || i <= 3));
        resource_int_value(device_get_name(dev), device_get_unit(dev),
            "direct", &ctlr->direct);
        /* Announce HW capabilities. */
        speed = (ctlr->caps & AHCI_CAP_ISS) >> AHCI_CAP_ISS_SHIFT;
        device_printf(dev,
                    "AHCI v%x.%02x with %d %sGbps ports, Port Multiplier %s%s\n",
                    ((version >> 20) & 0xf0) + ((version >> 16) & 0x0f),
                    ((version >> 4) & 0xf0) + (version & 0x0f),
                    (ctlr->caps & AHCI_CAP_NPMASK) + 1,
                    ((speed == 1) ? "1.5":((speed == 2) ? "3":
                    ((speed == 3) ? "6":"?"))),
                    (ctlr->caps & AHCI_CAP_SPM) ?
                    "supported" : "not supported",
                    (ctlr->caps & AHCI_CAP_FBSS) ?
                    " with FBS" : "");
        if (ctlr->quirks != 0) {
                device_printf(dev, "quirks=0x%b\n", ctlr->quirks,
                    AHCI_Q_BIT_STRING);
        }
        if (bootverbose) {
                device_printf(dev, "Caps:%s%s%s%s%s%s%s%s %sGbps",
                    (ctlr->caps & AHCI_CAP_64BIT) ? " 64bit":"",
                    (ctlr->caps & AHCI_CAP_SNCQ) ? " NCQ":"",
                    (ctlr->caps & AHCI_CAP_SSNTF) ? " SNTF":"",
                    (ctlr->caps & AHCI_CAP_SMPS) ? " MPS":"",
                    (ctlr->caps & AHCI_CAP_SSS) ? " SS":"",
                    (ctlr->caps & AHCI_CAP_SALP) ? " ALP":"",
                    (ctlr->caps & AHCI_CAP_SAL) ? " AL":"",
                    (ctlr->caps & AHCI_CAP_SCLO) ? " CLO":"",
                    ((speed == 1) ? "1.5":((speed == 2) ? "3":
                    ((speed == 3) ? "6":"?"))));
                printf("%s%s%s%s%s%s %dcmd%s%s%s %dports\n",
                    (ctlr->caps & AHCI_CAP_SAM) ? " AM":"",
                    (ctlr->caps & AHCI_CAP_SPM) ? " PM":"",
                    (ctlr->caps & AHCI_CAP_FBSS) ? " FBS":"",
                    (ctlr->caps & AHCI_CAP_PMD) ? " PMD":"",
                    (ctlr->caps & AHCI_CAP_SSC) ? " SSC":"",
                    (ctlr->caps & AHCI_CAP_PSC) ? " PSC":"",
                    ((ctlr->caps & AHCI_CAP_NCS) >> AHCI_CAP_NCS_SHIFT) + 1,
                    (ctlr->caps & AHCI_CAP_CCCS) ? " CCC":"",
                    (ctlr->caps & AHCI_CAP_EMS) ? " EM":"",
                    (ctlr->caps & AHCI_CAP_SXS) ? " eSATA":"",
                    (ctlr->caps & AHCI_CAP_NPMASK) + 1);
        }
        if (bootverbose && version >= 0x00010200) {
                device_printf(dev, "Caps2:%s%s%s%s%s%s\n",
                    (ctlr->caps2 & AHCI_CAP2_DESO) ? " DESO":"",
                    (ctlr->caps2 & AHCI_CAP2_SADM) ? " SADM":"",
                    (ctlr->caps2 & AHCI_CAP2_SDS) ? " SDS":"",
                    (ctlr->caps2 & AHCI_CAP2_APST) ? " APST":"",
                    (ctlr->caps2 & AHCI_CAP2_NVMP) ? " NVMP":"",
                    (ctlr->caps2 & AHCI_CAP2_BOH) ? " BOH":"");
        }
        /* Attach all channels on this controller */
        for (unit = 0; unit < ctlr->channels; unit++) {
                child = device_add_child(dev, "ahcich", DEVICE_UNIT_ANY);
                if (child == NULL) {
                        device_printf(dev, "failed to add channel device\n");
                        continue;
                }
                device_set_ivars(child, (void *)(intptr_t)unit);
                if ((ctlr->ichannels & (1 << unit)) == 0)
                        device_disable(child);
        }
        /* Attach any remapped NVME device */
        for (; unit < ctlr->channels + ctlr->remapped_devices; unit++) {
                child = device_add_child(dev, "nvme", DEVICE_UNIT_ANY);
                if (child == NULL) {
                        device_printf(dev, "failed to add remapped NVMe device");
                            continue;
                }
                device_set_ivars(child, (void *)(intptr_t)(unit | AHCI_REMAPPED_UNIT));
        }

        int em = (ctlr->caps & AHCI_CAP_EMS) != 0;
        resource_int_value(device_get_name(dev), device_get_unit(dev),
            "em", &em);
        if (em) {
                child = device_add_child(dev, "ahciem", DEVICE_UNIT_ANY);
                if (child == NULL)
                        device_printf(dev, "failed to add enclosure device\n");
                else
                        device_set_ivars(child, (void *)(intptr_t)AHCI_EM_UNIT);
        }
        bus_attach_children(dev);
        return (0);
}

int
ahci_detach(device_t dev)
{
        struct ahci_controller *ctlr = device_get_softc(dev);
        int error, i;

        /* Detach & delete all children */
        error = bus_generic_detach(dev);
        if (error != 0)
                return (error);

        /* Free interrupts. */
        for (i = 0; i < ctlr->numirqs; i++) {
                if (ctlr->irqs[i].r_irq) {
                        bus_teardown_intr(dev, ctlr->irqs[i].r_irq,
                            ctlr->irqs[i].handle);
                        bus_release_resource(dev, SYS_RES_IRQ,
                            ctlr->irqs[i].r_irq_rid, ctlr->irqs[i].r_irq);
                }
        }
        bus_dma_tag_destroy(ctlr->dma_tag);
        /* Free memory. */
        rman_fini(&ctlr->sc_iomem);
        ahci_free_mem(dev);
        mtx_destroy(&ctlr->ch_mtx);
        return (0);
}

void
ahci_free_mem(device_t dev)
{
        struct ahci_controller *ctlr = device_get_softc(dev);

        /* Release memory resources */
        if (ctlr->r_mem)
                bus_release_resource(dev, SYS_RES_MEMORY, ctlr->r_rid, ctlr->r_mem);
        if (ctlr->r_msix_table)
                bus_release_resource(dev, SYS_RES_MEMORY,
                    ctlr->r_msix_tab_rid, ctlr->r_msix_table);
        if (ctlr->r_msix_pba)
                bus_release_resource(dev, SYS_RES_MEMORY,
                    ctlr->r_msix_pba_rid, ctlr->r_msix_pba);

        ctlr->r_msix_pba = ctlr->r_mem = ctlr->r_msix_table = NULL;
}

int
ahci_setup_interrupt(device_t dev)
{
        struct ahci_controller *ctlr = device_get_softc(dev);
        int i;

        /* Check for single MSI vector fallback. */
        if (ctlr->numirqs > 1 &&
            (ATA_INL(ctlr->r_mem, AHCI_GHC) & AHCI_GHC_MRSM) != 0) {
                device_printf(dev, "Falling back to one MSI\n");
                ctlr->numirqs = 1;
        }

        /* Ensure we don't overrun irqs. */
        if (ctlr->numirqs > AHCI_MAX_IRQS) {
                device_printf(dev, "Too many irqs %d > %d (clamping)\n",
                    ctlr->numirqs, AHCI_MAX_IRQS);
                ctlr->numirqs = AHCI_MAX_IRQS;
        }

        /* Allocate all IRQs. */
        for (i = 0; i < ctlr->numirqs; i++) {
                ctlr->irqs[i].ctlr = ctlr;
                ctlr->irqs[i].r_irq_rid = i + (ctlr->msi ? 1 : 0);
                if (ctlr->channels == 1 && !ctlr->ccc && ctlr->msi)
                        ctlr->irqs[i].mode = AHCI_IRQ_MODE_ONE;
                else if (ctlr->numirqs == 1 || i >= ctlr->channels ||
                    (ctlr->ccc && i == ctlr->cccv))
                        ctlr->irqs[i].mode = AHCI_IRQ_MODE_ALL;
                else if (ctlr->channels > ctlr->numirqs &&
                    i == ctlr->numirqs - 1)
                        ctlr->irqs[i].mode = AHCI_IRQ_MODE_AFTER;
                else
                        ctlr->irqs[i].mode = AHCI_IRQ_MODE_ONE;
                if (!(ctlr->irqs[i].r_irq = bus_alloc_resource_any(dev, SYS_RES_IRQ,
                    &ctlr->irqs[i].r_irq_rid, RF_SHAREABLE | RF_ACTIVE))) {
                        device_printf(dev, "unable to map interrupt\n");
                        return (ENXIO);
                }
                if ((bus_setup_intr(dev, ctlr->irqs[i].r_irq, ATA_INTR_FLAGS, NULL,
                    (ctlr->irqs[i].mode != AHCI_IRQ_MODE_ONE) ? ahci_intr :
                     ((ctlr->quirks & AHCI_Q_EDGEIS) ? ahci_intr_one_edge :
                      ahci_intr_one),
                    &ctlr->irqs[i], &ctlr->irqs[i].handle))) {
                        /* SOS XXX release r_irq */
                        device_printf(dev, "unable to setup interrupt\n");
                        return (ENXIO);
                }
                if (ctlr->numirqs > 1) {
                        bus_describe_intr(dev, ctlr->irqs[i].r_irq,
                            ctlr->irqs[i].handle,
                            ctlr->irqs[i].mode == AHCI_IRQ_MODE_ONE ?
                            "ch%d" : "%d", i);
                }
        }
        return (0);
}

/*
 * Common case interrupt handler.
 */
static void
ahci_intr(void *data)
{
        struct ahci_controller_irq *irq = data;
        struct ahci_controller *ctlr = irq->ctlr;
        u_int32_t is, ise = 0;
        void *arg;
        int unit;

        if (irq->mode == AHCI_IRQ_MODE_ALL) {
                unit = 0;
                if (ctlr->ccc)
                        is = ctlr->ichannels;
                else
                        is = ATA_INL(ctlr->r_mem, AHCI_IS);
        } else {        /* AHCI_IRQ_MODE_AFTER */
                unit = irq->r_irq_rid - 1;
                is = ATA_INL(ctlr->r_mem, AHCI_IS);
                is &= (0xffffffff << unit);
        }
        /* CCC interrupt is edge triggered. */
        if (ctlr->ccc)
                ise = 1 << ctlr->cccv;
        /* Some controllers have edge triggered IS. */
        if (ctlr->quirks & AHCI_Q_EDGEIS)
                ise |= is;
        if (ise != 0)
                ATA_OUTL(ctlr->r_mem, AHCI_IS, ise);
        for (; unit < ctlr->channels; unit++) {
                if ((is & (1 << unit)) != 0 &&
                    (arg = ctlr->interrupt[unit].argument)) {
                                ctlr->interrupt[unit].function(arg);
                }
        }
        for (; unit < ctlr->channels + ctlr->remapped_devices; unit++) {
                if ((arg = ctlr->interrupt[unit].argument)) {
                        ctlr->interrupt[unit].function(arg);
                }
        }

        /* AHCI declares level triggered IS. */
        if (!(ctlr->quirks & AHCI_Q_EDGEIS))
                ATA_OUTL(ctlr->r_mem, AHCI_IS, is);
        ATA_RBL(ctlr->r_mem, AHCI_IS);
}

/*
 * Simplified interrupt handler for multivector MSI mode.
 */
static void
ahci_intr_one(void *data)
{
        struct ahci_controller_irq *irq = data;
        struct ahci_controller *ctlr = irq->ctlr;
        void *arg;
        int unit;

        unit = irq->r_irq_rid - 1;
        if ((arg = ctlr->interrupt[unit].argument))
            ctlr->interrupt[unit].function(arg);
        /* AHCI declares level triggered IS. */
        ATA_OUTL(ctlr->r_mem, AHCI_IS, 1 << unit);
        ATA_RBL(ctlr->r_mem, AHCI_IS);
}

static void
ahci_intr_one_edge(void *data)
{
        struct ahci_controller_irq *irq = data;
        struct ahci_controller *ctlr = irq->ctlr;
        void *arg;
        int unit;

        unit = irq->r_irq_rid - 1;
        /* Some controllers have edge triggered IS. */
        ATA_OUTL(ctlr->r_mem, AHCI_IS, 1 << unit);
        if ((arg = ctlr->interrupt[unit].argument))
                ctlr->interrupt[unit].function(arg);
        ATA_RBL(ctlr->r_mem, AHCI_IS);
}

struct resource *
ahci_alloc_resource(device_t dev, device_t child, int type, int rid,
    rman_res_t start, rman_res_t end, rman_res_t count, u_int flags)
{
        struct ahci_controller *ctlr = device_get_softc(dev);
        struct resource *res;
        rman_res_t st;
        int offset, size, unit;
        bool is_em, is_remapped;

        unit = (intptr_t)device_get_ivars(child);
        is_em = is_remapped = false;
        if (unit & AHCI_REMAPPED_UNIT) {
                unit &= AHCI_UNIT;
                unit -= ctlr->channels;
                is_remapped = true;
        } else if (unit & AHCI_EM_UNIT) {
                unit &= AHCI_UNIT;
                is_em = true;
        }
        res = NULL;
        switch (type) {
        case SYS_RES_MEMORY:
                if (is_remapped) {
                        offset = ctlr->remap_offset + unit * ctlr->remap_size;
                        size = ctlr->remap_size;
                } else if (!is_em) {
                        offset = AHCI_OFFSET + (unit << 7);
                        size = 128;
                } else if ((ctlr->caps & AHCI_CAP_EMS) == 0) {
                        break;
                } else if (rid == 0) {
                        offset = AHCI_EM_CTL;
                        size = 4;
                } else {
                        offset = (ctlr->emloc & 0xffff0000) >> 14;
                        size = (ctlr->emloc & 0x0000ffff) << 2;
                        if (rid != 1) {
                                if (rid == 2 && (ctlr->capsem &
                                    (AHCI_EM_XMT | AHCI_EM_SMB)) == 0)
                                        offset += size;
                                else
                                        break;
                        }
                }
                st = rman_get_start(ctlr->r_mem);
                res = rman_reserve_resource(&ctlr->sc_iomem, st + offset,
                    st + offset + size - 1, size, RF_ACTIVE, child);
                if (res) {
                        bus_space_handle_t bsh;
                        bus_space_tag_t bst;
                        bsh = rman_get_bushandle(ctlr->r_mem);
                        bst = rman_get_bustag(ctlr->r_mem);
                        bus_space_subregion(bst, bsh, offset, 128, &bsh);
                        rman_set_bushandle(res, bsh);
                        rman_set_bustag(res, bst);
                }
                break;
        case SYS_RES_IRQ:
                if (rid == ATA_IRQ_RID)
                        res = ctlr->irqs[0].r_irq;
                break;
        }
        return (res);
}

int
ahci_release_resource(device_t dev, device_t child, struct resource *r)
{

        switch (rman_get_type(r)) {
        case SYS_RES_MEMORY:
                rman_release_resource(r);
                return (0);
        case SYS_RES_IRQ:
                if (rman_get_rid(r) != ATA_IRQ_RID)
                        return (ENOENT);
                return (0);
        }
        return (EINVAL);
}

int
ahci_setup_intr(device_t dev, device_t child, struct resource *irq, 
    int flags, driver_filter_t *filter, driver_intr_t *function, 
    void *argument, void **cookiep)
{
        struct ahci_controller *ctlr = device_get_softc(dev);
        int unit = (intptr_t)device_get_ivars(child) & AHCI_UNIT;

        if (filter != NULL) {
                printf("ahci.c: we cannot use a filter here\n");
                return (EINVAL);
        }
        ctlr->interrupt[unit].function = function;
        ctlr->interrupt[unit].argument = argument;
        return (0);
}

int
ahci_teardown_intr(device_t dev, device_t child, struct resource *irq,
    void *cookie)
{
        struct ahci_controller *ctlr = device_get_softc(dev);
        int unit = (intptr_t)device_get_ivars(child) & AHCI_UNIT;

        ctlr->interrupt[unit].function = NULL;
        ctlr->interrupt[unit].argument = NULL;
        return (0);
}

int
ahci_print_child(device_t dev, device_t child)
{
        intptr_t ivars;
        int retval;

        retval = bus_print_child_header(dev, child);
        ivars = (intptr_t)device_get_ivars(child);
        if ((ivars & AHCI_EM_UNIT) == 0)
                retval += printf(" at channel %d", (int)ivars & AHCI_UNIT);
        retval += bus_print_child_footer(dev, child);
        return (retval);
}

int
ahci_child_location(device_t dev, device_t child, struct sbuf *sb)
{
        intptr_t ivars;

        ivars = (intptr_t)device_get_ivars(child);
        if ((ivars & AHCI_EM_UNIT) == 0)
                sbuf_printf(sb, "channel=%d", (int)ivars & AHCI_UNIT);
        return (0);
}

bus_dma_tag_t
ahci_get_dma_tag(device_t dev, device_t child)
{
        struct ahci_controller *ctlr = device_get_softc(dev);

        return (ctlr->dma_tag);
}

void
ahci_attached(device_t dev, struct ahci_channel *ch)
{
        struct ahci_controller *ctlr = device_get_softc(dev);

        mtx_lock(&ctlr->ch_mtx);
        ctlr->ch[ch->unit] = ch;
        mtx_unlock(&ctlr->ch_mtx);
}

void
ahci_detached(device_t dev, struct ahci_channel *ch)
{
        struct ahci_controller *ctlr = device_get_softc(dev);

        mtx_lock(&ctlr->ch_mtx);
        mtx_lock(&ch->mtx);
        ctlr->ch[ch->unit] = NULL;
        mtx_unlock(&ch->mtx);
        mtx_unlock(&ctlr->ch_mtx);
}

struct ahci_channel *
ahci_getch(device_t dev, int n)
{
        struct ahci_controller *ctlr = device_get_softc(dev);
        struct ahci_channel *ch;

        KASSERT(n >= 0 && n < AHCI_MAX_PORTS, ("Bad channel number %d", n));
        mtx_lock(&ctlr->ch_mtx);
        ch = ctlr->ch[n];
        if (ch != NULL)
                mtx_lock(&ch->mtx);
        mtx_unlock(&ctlr->ch_mtx);
        return (ch);
}

void
ahci_putch(struct ahci_channel *ch)
{

        mtx_unlock(&ch->mtx);
}

static int
ahci_ch_probe(device_t dev)
{

        device_set_desc(dev, "AHCI channel");
        return (BUS_PROBE_DEFAULT);
}

static int
ahci_ch_disablephy_proc(SYSCTL_HANDLER_ARGS)
{
        struct ahci_channel *ch;
        int error, value;

        ch = arg1;
        value = ch->disablephy;
        error = sysctl_handle_int(oidp, &value, 0, req);
        if (error != 0 || req->newptr == NULL || (value != 0 && value != 1))
                return (error);

        mtx_lock(&ch->mtx);
        ch->disablephy = value;
        if (value) {
                ahci_ch_deinit(ch->dev);
        } else {
                ahci_ch_init(ch->dev);
                ahci_phy_check_events(ch, ATA_SE_PHY_CHANGED | ATA_SE_EXCHANGED);
        }
        mtx_unlock(&ch->mtx);

        return (0);
}

static int
ahci_ch_attach(device_t dev)
{
        struct ahci_controller *ctlr = device_get_softc(device_get_parent(dev));
        struct ahci_channel *ch = device_get_softc(dev);
        struct cam_devq *devq;
        struct sysctl_ctx_list *ctx;
        struct sysctl_oid *tree;
        int rid, error, i, sata_rev = 0;
        u_int32_t version;

        ch->dev = dev;
        ch->unit = (intptr_t)device_get_ivars(dev);
        ch->caps = ctlr->caps;
        ch->caps2 = ctlr->caps2;
        ch->start = ctlr->ch_start;
        ch->quirks = ctlr->quirks;
        ch->vendorid = ctlr->vendorid;
        ch->deviceid = ctlr->deviceid;
        ch->subvendorid = ctlr->subvendorid;
        ch->subdeviceid = ctlr->subdeviceid;
        ch->numslots = ((ch->caps & AHCI_CAP_NCS) >> AHCI_CAP_NCS_SHIFT) + 1;
        mtx_init(&ch->mtx, "AHCI channel lock", NULL, MTX_DEF);
        ch->pm_level = 0;
        resource_int_value(device_get_name(dev),
            device_get_unit(dev), "pm_level", &ch->pm_level);
        STAILQ_INIT(&ch->doneq);
        if (ch->pm_level > 3)
                callout_init_mtx(&ch->pm_timer, &ch->mtx, 0);
        callout_init_mtx(&ch->reset_timer, &ch->mtx, 0);
        /* JMicron external ports (0) sometimes limited */
        if ((ctlr->quirks & AHCI_Q_SATA1_UNIT0) && ch->unit == 0)
                sata_rev = 1;
        if (ch->quirks & AHCI_Q_SATA2)
                sata_rev = 2;
        resource_int_value(device_get_name(dev),
            device_get_unit(dev), "sata_rev", &sata_rev);
        for (i = 0; i < 16; i++) {
                ch->user[i].revision = sata_rev;
                ch->user[i].mode = 0;
                ch->user[i].bytecount = 8192;
                ch->user[i].tags = ch->numslots;
                ch->user[i].caps = 0;
                ch->curr[i] = ch->user[i];
                if (ch->pm_level) {
                        ch->user[i].caps = CTS_SATA_CAPS_H_PMREQ |
                            CTS_SATA_CAPS_H_APST |
                            CTS_SATA_CAPS_D_PMREQ | CTS_SATA_CAPS_D_APST;
                }
                ch->user[i].caps |= CTS_SATA_CAPS_H_DMAAA |
                    CTS_SATA_CAPS_H_AN;
        }
        rid = 0;
        if (!(ch->r_mem = bus_alloc_resource_any(dev, SYS_RES_MEMORY,
            &rid, RF_ACTIVE)))
                return (ENXIO);
        ch->chcaps = ATA_INL(ch->r_mem, AHCI_P_CMD);
        version = ATA_INL(ctlr->r_mem, AHCI_VS);
        if (version < 0x00010200 && (ctlr->caps & AHCI_CAP_FBSS))
                ch->chcaps |= AHCI_P_CMD_FBSCP;
        if (ch->caps2 & AHCI_CAP2_SDS)
                ch->chscaps = ATA_INL(ch->r_mem, AHCI_P_DEVSLP);
        if (bootverbose) {
                device_printf(dev, "Caps:%s%s%s%s%s%s\n",
                    (ch->chcaps & AHCI_P_CMD_HPCP) ? " HPCP":"",
                    (ch->chcaps & AHCI_P_CMD_MPSP) ? " MPSP":"",
                    (ch->chcaps & AHCI_P_CMD_CPD) ? " CPD":"",
                    (ch->chcaps & AHCI_P_CMD_ESP) ? " ESP":"",
                    (ch->chcaps & AHCI_P_CMD_FBSCP) ? " FBSCP":"",
                    (ch->chscaps & AHCI_P_DEVSLP_DSP) ? " DSP":"");
        }
        ahci_dmainit(dev);
        ahci_slotsalloc(dev);
        mtx_lock(&ch->mtx);
        ahci_ch_init(dev);
        rid = ATA_IRQ_RID;
        if (!(ch->r_irq = bus_alloc_resource_any(dev, SYS_RES_IRQ,
            &rid, RF_SHAREABLE | RF_ACTIVE))) {
                device_printf(dev, "Unable to map interrupt\n");
                error = ENXIO;
                goto err0;
        }
        if ((bus_setup_intr(dev, ch->r_irq, ATA_INTR_FLAGS, NULL,
            ctlr->direct ? ahci_ch_intr_direct : ahci_ch_intr,
            ch, &ch->ih))) {
                device_printf(dev, "Unable to setup interrupt\n");
                error = ENXIO;
                goto err1;
        }
        /* Create the device queue for our SIM. */
        devq = cam_simq_alloc(ch->numslots);
        if (devq == NULL) {
                device_printf(dev, "Unable to allocate simq\n");
                error = ENOMEM;
                goto err1;
        }
        /* Construct SIM entry */
        ch->sim = cam_sim_alloc(ahciaction, ahcipoll, "ahcich", ch,
            device_get_unit(dev), (struct mtx *)&ch->mtx,
            (ch->quirks & AHCI_Q_NOCCS) ? 1 : min(2, ch->numslots),
            (ch->caps & AHCI_CAP_SNCQ) ? ch->numslots : 0,
            devq);
        if (ch->sim == NULL) {
                cam_simq_free(devq);
                device_printf(dev, "unable to allocate sim\n");
                error = ENOMEM;
                goto err1;
        }
        if (xpt_bus_register(ch->sim, dev, 0) != CAM_SUCCESS) {
                device_printf(dev, "unable to register xpt bus\n");
                error = ENXIO;
                goto err2;
        }
        if (xpt_create_path(&ch->path, /*periph*/NULL, cam_sim_path(ch->sim),
            CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD) != CAM_REQ_CMP) {
                device_printf(dev, "unable to create path\n");
                error = ENXIO;
                goto err3;
        }
        if (ch->pm_level > 3) {
                callout_reset(&ch->pm_timer,
                    (ch->pm_level == 4) ? hz / 1000 : hz / 8,
                    ahci_ch_pm, ch);
        }
        mtx_unlock(&ch->mtx);
        ahci_attached(device_get_parent(dev), ch);
        ctx = device_get_sysctl_ctx(dev);
        tree = device_get_sysctl_tree(dev);
        SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO, "disable_phy",
            CTLFLAG_RW | CTLTYPE_UINT | CTLFLAG_MPSAFE, ch,
            0, ahci_ch_disablephy_proc, "IU", "Disable PHY");
        return (0);

err3:
        xpt_bus_deregister(cam_sim_path(ch->sim));
err2:
        cam_sim_free(ch->sim, /*free_devq*/TRUE);
err1:
        bus_release_resource(dev, SYS_RES_IRQ, ATA_IRQ_RID, ch->r_irq);
err0:
        bus_release_resource(dev, SYS_RES_MEMORY, ch->unit, ch->r_mem);
        mtx_unlock(&ch->mtx);
        mtx_destroy(&ch->mtx);
        return (error);
}

static int
ahci_ch_detach(device_t dev)
{
        struct ahci_channel *ch = device_get_softc(dev);

        ahci_detached(device_get_parent(dev), ch);
        mtx_lock(&ch->mtx);
        xpt_async(AC_LOST_DEVICE, ch->path, NULL);
        /* Forget about reset. */
        if (ch->resetting) {
                ch->resetting = 0;
                xpt_release_simq(ch->sim, TRUE);
        }
        xpt_free_path(ch->path);
        xpt_bus_deregister(cam_sim_path(ch->sim));
        cam_sim_free(ch->sim, /*free_devq*/TRUE);
        mtx_unlock(&ch->mtx);

        if (ch->pm_level > 3)
                callout_drain(&ch->pm_timer);
        callout_drain(&ch->reset_timer);
        bus_teardown_intr(dev, ch->r_irq, ch->ih);
        bus_release_resource(dev, SYS_RES_IRQ, ATA_IRQ_RID, ch->r_irq);

        ahci_ch_deinit(dev);
        ahci_slotsfree(dev);
        ahci_dmafini(dev);

        bus_release_resource(dev, SYS_RES_MEMORY, ch->unit, ch->r_mem);
        mtx_destroy(&ch->mtx);
        return (0);
}

static int
ahci_ch_init(device_t dev)
{
        struct ahci_channel *ch = device_get_softc(dev);
        uint64_t work;

        /* Disable port interrupts */
        ATA_OUTL(ch->r_mem, AHCI_P_IE, 0);
        /* Setup work areas */
        work = ch->dma.work_bus + AHCI_CL_OFFSET;
        ATA_OUTL(ch->r_mem, AHCI_P_CLB, work & 0xffffffff);
        ATA_OUTL(ch->r_mem, AHCI_P_CLBU, work >> 32);
        work = ch->dma.rfis_bus;
        ATA_OUTL(ch->r_mem, AHCI_P_FB, work & 0xffffffff); 
        ATA_OUTL(ch->r_mem, AHCI_P_FBU, work >> 32);
        /* Activate the channel and power/spin up device */
        ATA_OUTL(ch->r_mem, AHCI_P_CMD,
             (AHCI_P_CMD_ACTIVE | AHCI_P_CMD_POD | AHCI_P_CMD_SUD |
             ((ch->pm_level == 2 || ch->pm_level == 3) ? AHCI_P_CMD_ALPE : 0) |
             ((ch->pm_level > 2) ? AHCI_P_CMD_ASP : 0 )));
        ahci_start_fr(ch);
        ahci_start(ch, 1);
        return (0);
}

static int
ahci_ch_deinit(device_t dev)
{
        struct ahci_channel *ch = device_get_softc(dev);

        /* Disable port interrupts. */
        ATA_OUTL(ch->r_mem, AHCI_P_IE, 0);
        /* Reset command register. */
        ahci_stop(ch);
        ahci_stop_fr(ch);
        ATA_OUTL(ch->r_mem, AHCI_P_CMD, 0);
        /* Allow everything, including partial and slumber modes. */
        ATA_OUTL(ch->r_mem, AHCI_P_SCTL, 0);
        /* Request slumber mode transition and give some time to get there. */
        ATA_OUTL(ch->r_mem, AHCI_P_CMD, AHCI_P_CMD_SLUMBER);
        DELAY(100);
        /* Disable PHY. */
        ATA_OUTL(ch->r_mem, AHCI_P_SCTL, ATA_SC_DET_DISABLE);
        return (0);
}

static int
ahci_ch_suspend(device_t dev)
{
        struct ahci_channel *ch = device_get_softc(dev);

        mtx_lock(&ch->mtx);
        xpt_freeze_simq(ch->sim, 1);
        /* Forget about reset. */
        if (ch->resetting) {
                ch->resetting = 0;
                callout_stop(&ch->reset_timer);
                xpt_release_simq(ch->sim, TRUE);
        }
        while (ch->oslots)
                msleep(ch, &ch->mtx, PRIBIO, "ahcisusp", hz/100);
        ahci_ch_deinit(dev);
        mtx_unlock(&ch->mtx);
        return (0);
}

static int
ahci_ch_resume(device_t dev)
{
        struct ahci_channel *ch = device_get_softc(dev);

        mtx_lock(&ch->mtx);
        ahci_ch_init(dev);
        ahci_reset(ch);
        xpt_release_simq(ch->sim, TRUE);
        mtx_unlock(&ch->mtx);
        return (0);
}

static device_method_t ahcich_methods[] = {
        DEVMETHOD(device_probe,     ahci_ch_probe),
        DEVMETHOD(device_attach,    ahci_ch_attach),
        DEVMETHOD(device_detach,    ahci_ch_detach),
        DEVMETHOD(device_suspend,   ahci_ch_suspend),
        DEVMETHOD(device_resume,    ahci_ch_resume),
        DEVMETHOD_END
};
static driver_t ahcich_driver = {
        "ahcich",
        ahcich_methods,
        sizeof(struct ahci_channel)
};
DRIVER_MODULE(ahcich, ahci, ahcich_driver, NULL, NULL);

struct ahci_dc_cb_args {
        bus_addr_t maddr;
        int error;
};

static void
ahci_dmainit(device_t dev)
{
        struct ahci_channel *ch = device_get_softc(dev);
        struct ahci_dc_cb_args dcba;
        size_t rfsize;
        int error;

        /* Command area. */
        error = bus_dma_tag_create(bus_get_dma_tag(dev), 1024, 0,
            BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR,
            NULL, NULL, AHCI_WORK_SIZE, 1, AHCI_WORK_SIZE,
            0, NULL, NULL, &ch->dma.work_tag);
        if (error != 0)
                goto error;
        error = bus_dmamem_alloc(ch->dma.work_tag, (void **)&ch->dma.work,
            BUS_DMA_ZERO, &ch->dma.work_map);
        if (error != 0)
                goto error;
        error = bus_dmamap_load(ch->dma.work_tag, ch->dma.work_map, ch->dma.work,
            AHCI_WORK_SIZE, ahci_dmasetupc_cb, &dcba, BUS_DMA_NOWAIT);
        if (error != 0 || (error = dcba.error) != 0) {
                bus_dmamem_free(ch->dma.work_tag, ch->dma.work, ch->dma.work_map);
                goto error;
        }
        ch->dma.work_bus = dcba.maddr;
        /* FIS receive area. */
        if (ch->chcaps & AHCI_P_CMD_FBSCP)
            rfsize = 4096;
        else
            rfsize = 256;
        error = bus_dma_tag_create(bus_get_dma_tag(dev), rfsize, 0,
            BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR,
            NULL, NULL, rfsize, 1, rfsize,
            0, NULL, NULL, &ch->dma.rfis_tag);
        if (error != 0)
                goto error;
        error = bus_dmamem_alloc(ch->dma.rfis_tag, (void **)&ch->dma.rfis, 0,
            &ch->dma.rfis_map);
        if (error != 0)
                goto error;
        error = bus_dmamap_load(ch->dma.rfis_tag, ch->dma.rfis_map, ch->dma.rfis,
            rfsize, ahci_dmasetupc_cb, &dcba, BUS_DMA_NOWAIT);
        if (error != 0 || (error = dcba.error) != 0) {
                bus_dmamem_free(ch->dma.rfis_tag, ch->dma.rfis, ch->dma.rfis_map);
                goto error;
        }
        ch->dma.rfis_bus = dcba.maddr;
        /* Data area. */
        error = bus_dma_tag_create(bus_get_dma_tag(dev), 2, 0,
            BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR,
            NULL, NULL,
            AHCI_SG_ENTRIES * PAGE_SIZE, AHCI_SG_ENTRIES, AHCI_PRD_MAX,
            0, busdma_lock_mutex, &ch->mtx, &ch->dma.data_tag);
        if (error != 0)
                goto error;
        return;

error:
        device_printf(dev, "WARNING - DMA initialization failed, error %d\n",
            error);
        ahci_dmafini(dev);
}

static void
ahci_dmasetupc_cb(void *xsc, bus_dma_segment_t *segs, int nsegs, int error)
{
        struct ahci_dc_cb_args *dcba = (struct ahci_dc_cb_args *)xsc;

        if (!(dcba->error = error))
                dcba->maddr = segs[0].ds_addr;
}

static void
ahci_dmafini(device_t dev)
{
        struct ahci_channel *ch = device_get_softc(dev);

        if (ch->dma.data_tag) {
                bus_dma_tag_destroy(ch->dma.data_tag);
                ch->dma.data_tag = NULL;
        }
        if (ch->dma.rfis_bus) {
                bus_dmamap_unload(ch->dma.rfis_tag, ch->dma.rfis_map);
                bus_dmamem_free(ch->dma.rfis_tag, ch->dma.rfis, ch->dma.rfis_map);
                ch->dma.rfis_bus = 0;
                ch->dma.rfis = NULL;
        }
        if (ch->dma.work_bus) {
                bus_dmamap_unload(ch->dma.work_tag, ch->dma.work_map);
                bus_dmamem_free(ch->dma.work_tag, ch->dma.work, ch->dma.work_map);
                ch->dma.work_bus = 0;
                ch->dma.work = NULL;
        }
        if (ch->dma.work_tag) {
                bus_dma_tag_destroy(ch->dma.work_tag);
                ch->dma.work_tag = NULL;
        }
}

static void
ahci_slotsalloc(device_t dev)
{
        struct ahci_channel *ch = device_get_softc(dev);
        int i;

        /* Alloc and setup command/dma slots */
        bzero(ch->slot, sizeof(ch->slot));
        for (i = 0; i < ch->numslots; i++) {
                struct ahci_slot *slot = &ch->slot[i];

                slot->ch = ch;
                slot->slot = i;
                slot->state = AHCI_SLOT_EMPTY;
                slot->ct_offset = AHCI_CT_OFFSET + AHCI_CT_SIZE * i;
                slot->ccb = NULL;
                callout_init_mtx(&slot->timeout, &ch->mtx, 0);

                if (bus_dmamap_create(ch->dma.data_tag, 0, &slot->dma.data_map))
                        device_printf(ch->dev, "FAILURE - create data_map\n");
        }
}

static void
ahci_slotsfree(device_t dev)
{
        struct ahci_channel *ch = device_get_softc(dev);
        int i;

        /* Free all dma slots */
        for (i = 0; i < ch->numslots; i++) {
                struct ahci_slot *slot = &ch->slot[i];

                callout_drain(&slot->timeout);
                if (slot->dma.data_map) {
                        bus_dmamap_destroy(ch->dma.data_tag, slot->dma.data_map);
                        slot->dma.data_map = NULL;
                }
        }
}

static int
ahci_phy_check_events(struct ahci_channel *ch, u_int32_t serr)
{

        if (((ch->pm_level == 0) && (serr & ATA_SE_PHY_CHANGED)) ||
            ((ch->pm_level != 0 || ch->listening) && (serr & ATA_SE_EXCHANGED))) {
                u_int32_t status = ATA_INL(ch->r_mem, AHCI_P_SSTS);
                union ccb *ccb;

                if (bootverbose) {
                        if ((status & ATA_SS_DET_MASK) != ATA_SS_DET_NO_DEVICE)
                                device_printf(ch->dev, "CONNECT requested\n");
                        else
                                device_printf(ch->dev, "DISCONNECT requested\n");
                }
                ahci_reset(ch);
                if ((ccb = xpt_alloc_ccb_nowait()) == NULL)
                        return (0);
                if (xpt_create_path(&ccb->ccb_h.path, NULL,
                    cam_sim_path(ch->sim),
                    CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD) != CAM_REQ_CMP) {
                        xpt_free_ccb(ccb);
                        return (0);
                }
                xpt_rescan(ccb);
                return (1);
        }
        return (0);
}

static void
ahci_cpd_check_events(struct ahci_channel *ch)
{
        u_int32_t status;
        union ccb *ccb;
        device_t dev;

        if (ch->pm_level == 0)
                return;

        status = ATA_INL(ch->r_mem, AHCI_P_CMD);
        if ((status & AHCI_P_CMD_CPD) == 0)
                return;

        if (bootverbose) {
                dev = ch->dev;
                if (status & AHCI_P_CMD_CPS) {
                        device_printf(dev, "COLD CONNECT requested\n");
                } else
                        device_printf(dev, "COLD DISCONNECT requested\n");
        }
        ahci_reset(ch);
        if ((ccb = xpt_alloc_ccb_nowait()) == NULL)
                return;
        if (xpt_create_path(&ccb->ccb_h.path, NULL, cam_sim_path(ch->sim),
            CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD) != CAM_REQ_CMP) {
                xpt_free_ccb(ccb);
                return;
        }
        xpt_rescan(ccb);
}

static void
ahci_notify_events(struct ahci_channel *ch, u_int32_t status)
{
        struct cam_path *dpath;
        int i;

        if (ch->caps & AHCI_CAP_SSNTF)
                ATA_OUTL(ch->r_mem, AHCI_P_SNTF, status);
        if (bootverbose)
                device_printf(ch->dev, "SNTF 0x%04x\n", status);
        for (i = 0; i < 16; i++) {
                if ((status & (1 << i)) == 0)
                        continue;
                if (xpt_create_path(&dpath, NULL,
                    xpt_path_path_id(ch->path), i, 0) == CAM_REQ_CMP) {
                        xpt_async(AC_SCSI_AEN, dpath, NULL);
                        xpt_free_path(dpath);
                }
        }
}

static void
ahci_done(struct ahci_channel *ch, union ccb *ccb)
{

        mtx_assert(&ch->mtx, MA_OWNED);
        if ((ccb->ccb_h.func_code & XPT_FC_QUEUED) == 0 ||
            ch->batch == 0) {
                xpt_done(ccb);
                return;
        }

        STAILQ_INSERT_TAIL(&ch->doneq, &ccb->ccb_h, sim_links.stqe);
}

static void
ahci_ch_intr(void *arg)
{
        struct ahci_channel *ch = (struct ahci_channel *)arg;
        uint32_t istatus;

        /* Read interrupt statuses. */
        istatus = ATA_INL(ch->r_mem, AHCI_P_IS);

        mtx_lock(&ch->mtx);
        ahci_ch_intr_main(ch, istatus);
        mtx_unlock(&ch->mtx);
}

static void
ahci_ch_intr_direct(void *arg)
{
        struct ahci_channel *ch = (struct ahci_channel *)arg;
        struct ccb_hdr *ccb_h;
        uint32_t istatus;
        STAILQ_HEAD(, ccb_hdr) tmp_doneq = STAILQ_HEAD_INITIALIZER(tmp_doneq);

        /* Read interrupt statuses. */
        istatus = ATA_INL(ch->r_mem, AHCI_P_IS);

        mtx_lock(&ch->mtx);
        ch->batch = 1;
        ahci_ch_intr_main(ch, istatus);
        ch->batch = 0;
        /*
         * Prevent the possibility of issues caused by processing the queue
         * while unlocked below by moving the contents to a local queue.
         */
        STAILQ_CONCAT(&tmp_doneq, &ch->doneq);
        mtx_unlock(&ch->mtx);
        while ((ccb_h = STAILQ_FIRST(&tmp_doneq)) != NULL) {
                STAILQ_REMOVE_HEAD(&tmp_doneq, sim_links.stqe);
                xpt_done_direct((union ccb *)ccb_h);
        }
}

static void
ahci_ch_pm(void *arg)
{
        struct ahci_channel *ch = (struct ahci_channel *)arg;
        uint32_t work;

        if (ch->numrslots != 0)
                return;
        work = ATA_INL(ch->r_mem, AHCI_P_CMD);
        if (ch->pm_level == 4)
                work |= AHCI_P_CMD_PARTIAL;
        else
                work |= AHCI_P_CMD_SLUMBER;
        ATA_OUTL(ch->r_mem, AHCI_P_CMD, work);
}

static void
ahci_ch_intr_main(struct ahci_channel *ch, uint32_t istatus)
{
        uint32_t cstatus, serr = 0, sntf = 0, ok, err;
        enum ahci_err_type et;
        int i, ccs, port, reset = 0;

        /* Clear interrupt statuses. */
        ATA_OUTL(ch->r_mem, AHCI_P_IS, istatus);
        /* Read command statuses. */
        if (ch->numtslots != 0)
                cstatus = ATA_INL(ch->r_mem, AHCI_P_SACT);
        else
                cstatus = 0;
        if (ch->numrslots != ch->numtslots)
                cstatus |= ATA_INL(ch->r_mem, AHCI_P_CI);
        /* Read SNTF in one of possible ways. */
        if ((istatus & AHCI_P_IX_SDB) &&
            (ch->pm_present || ch->curr[0].atapi != 0)) {
                if (ch->caps & AHCI_CAP_SSNTF)
                        sntf = ATA_INL(ch->r_mem, AHCI_P_SNTF);
                else if (ch->fbs_enabled) {
                        u_int8_t *fis = ch->dma.rfis + 0x58;

                        for (i = 0; i < 16; i++) {
                                if (fis[1] & 0x80) {
                                        fis[1] &= 0x7f;
                                        sntf |= 1 << i;
                                }
                                fis += 256;
                        }
                } else {
                        u_int8_t *fis = ch->dma.rfis + 0x58;

                        if (fis[1] & 0x80)
                                sntf = (1 << (fis[1] & 0x0f));
                }
        }
        /* Process PHY events */
        if (istatus & (AHCI_P_IX_PC | AHCI_P_IX_PRC | AHCI_P_IX_OF |
            AHCI_P_IX_IF | AHCI_P_IX_HBD | AHCI_P_IX_HBF | AHCI_P_IX_TFE)) {
                serr = ATA_INL(ch->r_mem, AHCI_P_SERR);
                if (serr) {
                        ATA_OUTL(ch->r_mem, AHCI_P_SERR, serr);
                        reset = ahci_phy_check_events(ch, serr);
                }
        }
        /* Process cold presence detection events */
        if ((istatus & AHCI_P_IX_CPD) && !reset)
                ahci_cpd_check_events(ch);
        /* Process command errors */
        if (istatus & (AHCI_P_IX_OF | AHCI_P_IX_IF |
            AHCI_P_IX_HBD | AHCI_P_IX_HBF | AHCI_P_IX_TFE)) {
                if (ch->quirks & AHCI_Q_NOCCS) {
                        /*
                         * ASMedia chips sometimes report failed commands as
                         * completed.  Count all running commands as failed.
                         */
                        cstatus |= ch->rslots;

                        /* They also report wrong CCS, so try to guess one. */
                        ccs = powerof2(cstatus) ? ffs(cstatus) - 1 : -1;
                } else {
                        ccs = (ATA_INL(ch->r_mem, AHCI_P_CMD) &
                            AHCI_P_CMD_CCS_MASK) >> AHCI_P_CMD_CCS_SHIFT;
                }
//device_printf(dev, "%s ERROR is %08x cs %08x ss %08x rs %08x tfd %02x serr %08x fbs %08x ccs %d\n",
//    __func__, istatus, cstatus, sstatus, ch->rslots, ATA_INL(ch->r_mem, AHCI_P_TFD),
//    serr, ATA_INL(ch->r_mem, AHCI_P_FBS), ccs);
                port = -1;
                if (ch->fbs_enabled) {
                        uint32_t fbs = ATA_INL(ch->r_mem, AHCI_P_FBS);
                        if (fbs & AHCI_P_FBS_SDE) {
                                port = (fbs & AHCI_P_FBS_DWE)
                                    >> AHCI_P_FBS_DWE_SHIFT;
                        } else {
                                for (i = 0; i < 16; i++) {
                                        if (ch->numrslotspd[i] == 0)
                                                continue;
                                        if (port == -1)
                                                port = i;
                                        else if (port != i) {
                                                port = -2;
                                                break;
                                        }
                                }
                        }
                }
                err = ch->rslots & cstatus;
        } else {
                ccs = 0;
                err = 0;
                port = -1;
        }
        /* Complete all successful commands. */
        ok = ch->rslots & ~cstatus;
        for (i = 0; i < ch->numslots; i++) {
                if ((ok >> i) & 1)
                        ahci_end_transaction(&ch->slot[i], AHCI_ERR_NONE);
        }
        /* On error, complete the rest of commands with error statuses. */
        if (err) {
                if (ch->frozen) {
                        union ccb *fccb = ch->frozen;
                        ch->frozen = NULL;
                        fccb->ccb_h.status = CAM_REQUEUE_REQ | CAM_RELEASE_SIMQ;
                        if (!(fccb->ccb_h.status & CAM_DEV_QFRZN)) {
                                xpt_freeze_devq(fccb->ccb_h.path, 1);
                                fccb->ccb_h.status |= CAM_DEV_QFRZN;
                        }
                        ahci_done(ch, fccb);
                }
                for (i = 0; i < ch->numslots; i++) {
                        /* XXX: requests in loading state. */
                        if (((err >> i) & 1) == 0)
                                continue;
                        if (port >= 0 &&
                            ch->slot[i].ccb->ccb_h.target_id != port)
                                continue;
                        if (istatus & AHCI_P_IX_TFE) {
                            if (port != -2) {
                                /* Task File Error */
                                if (ch->numtslotspd[
                                    ch->slot[i].ccb->ccb_h.target_id] == 0) {
                                        /* Untagged operation. */
                                        if (i == ccs)
                                                et = AHCI_ERR_TFE;
                                        else
                                                et = AHCI_ERR_INNOCENT;
                                } else {
                                        /* Tagged operation. */
                                        et = AHCI_ERR_NCQ;
                                }
                            } else {
                                et = AHCI_ERR_TFE;
                                ch->fatalerr = 1;
                            }
                        } else if (istatus & AHCI_P_IX_IF) {
                                if (ch->numtslots == 0 && i != ccs && port != -2)
                                        et = AHCI_ERR_INNOCENT;
                                else
                                        et = AHCI_ERR_SATA;
                        } else
                                et = AHCI_ERR_INVALID;
                        ahci_end_transaction(&ch->slot[i], et);
                }
                /*
                 * We can't reinit port if there are some other
                 * commands active, use resume to complete them.
                 */
                if (ch->rslots != 0 && !ch->recoverycmd)
                        ATA_OUTL(ch->r_mem, AHCI_P_FBS, AHCI_P_FBS_EN | AHCI_P_FBS_DEC);
        }
        /* Process NOTIFY events */
        if (sntf)
                ahci_notify_events(ch, sntf);
}

/* Must be called with channel locked. */
static int
ahci_check_collision(struct ahci_channel *ch, union ccb *ccb)
{
        int t = ccb->ccb_h.target_id;

        if ((ccb->ccb_h.func_code == XPT_ATA_IO) &&
            (ccb->ataio.cmd.flags & CAM_ATAIO_FPDMA)) {
                /* Tagged command while we have no supported tag free. */
                if (((~ch->oslots) & (0xffffffff >> (32 -
                    ch->curr[t].tags))) == 0)
                        return (1);
                /* If we have FBS */
                if (ch->fbs_enabled) {
                        /* Tagged command while untagged are active. */
                        if (ch->numrslotspd[t] != 0 && ch->numtslotspd[t] == 0)
                                return (1);
                } else {
                        /* Tagged command while untagged are active. */
                        if (ch->numrslots != 0 && ch->numtslots == 0)
                                return (1);
                        /* Tagged command while tagged to other target is active. */
                        if (ch->numtslots != 0 &&
                            ch->taggedtarget != ccb->ccb_h.target_id)
                                return (1);
                }
        } else {
                /* If we have FBS */
                if (ch->fbs_enabled) {
                        /* Untagged command while tagged are active. */
                        if (ch->numrslotspd[t] != 0 && ch->numtslotspd[t] != 0)
                                return (1);
                } else {
                        /* Untagged command while tagged are active. */
                        if (ch->numrslots != 0 && ch->numtslots != 0)
                                return (1);
                }
        }
        if ((ccb->ccb_h.func_code == XPT_ATA_IO) &&
            (ccb->ataio.cmd.flags & (CAM_ATAIO_CONTROL | CAM_ATAIO_NEEDRESULT))) {
                /* Atomic command while anything active. */
                if (ch->numrslots != 0)
                        return (1);
        }
       /* We have some atomic command running. */
       if (ch->aslots != 0)
               return (1);
        return (0);
}

/* Must be called with channel locked. */
static void
ahci_begin_transaction(struct ahci_channel *ch, union ccb *ccb)
{
        struct ahci_slot *slot;
        int tag, tags;

        /* Choose empty slot. */
        tags = ch->numslots;
        if ((ccb->ccb_h.func_code == XPT_ATA_IO) &&
            (ccb->ataio.cmd.flags & CAM_ATAIO_FPDMA))
                tags = ch->curr[ccb->ccb_h.target_id].tags;
        if (ch->lastslot + 1 < tags)
                tag = ffs(~(ch->oslots >> (ch->lastslot + 1)));
        else
                tag = 0;
        if (tag == 0 || tag + ch->lastslot >= tags)
                tag = ffs(~ch->oslots) - 1;
        else
                tag += ch->lastslot;
        ch->lastslot = tag;
        /* Occupy chosen slot. */
        slot = &ch->slot[tag];
        slot->ccb = ccb;
        /* Stop PM timer. */
        if (ch->numrslots == 0 && ch->pm_level > 3)
                callout_stop(&ch->pm_timer);
        /* Update channel stats. */
        ch->oslots |= (1 << tag);
        ch->numrslots++;
        ch->numrslotspd[ccb->ccb_h.target_id]++;
        if ((ccb->ccb_h.func_code == XPT_ATA_IO) &&
            (ccb->ataio.cmd.flags & CAM_ATAIO_FPDMA)) {
                ch->numtslots++;
                ch->numtslotspd[ccb->ccb_h.target_id]++;
                ch->taggedtarget = ccb->ccb_h.target_id;
        }
        if ((ccb->ccb_h.func_code == XPT_ATA_IO) &&
            (ccb->ataio.cmd.flags & (CAM_ATAIO_CONTROL | CAM_ATAIO_NEEDRESULT)))
                ch->aslots |= (1 << tag);
        if ((ccb->ccb_h.flags & CAM_DIR_MASK) != CAM_DIR_NONE) {
                slot->state = AHCI_SLOT_LOADING;
                bus_dmamap_load_ccb(ch->dma.data_tag, slot->dma.data_map, ccb,
                    ahci_dmasetprd, slot, 0);
        } else {
                slot->dma.nsegs = 0;
                ahci_execute_transaction(slot);
        }
}

/* Locked by busdma engine. */
static void
ahci_dmasetprd(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
{    
        struct ahci_slot *slot = arg;
        struct ahci_channel *ch = slot->ch;
        struct ahci_cmd_tab *ctp;
        struct ahci_dma_prd *prd;
        int i;

        if (error) {
                device_printf(ch->dev, "DMA load error\n");
                ahci_end_transaction(slot, AHCI_ERR_INVALID);
                return;
        }
        KASSERT(nsegs <= AHCI_SG_ENTRIES, ("too many DMA segment entries\n"));
        /* Get a piece of the workspace for this request */
        ctp = (struct ahci_cmd_tab *)(ch->dma.work + slot->ct_offset);
        /* Fill S/G table */
        prd = &ctp->prd_tab[0];
        for (i = 0; i < nsegs; i++) {
                prd[i].dba = htole64(segs[i].ds_addr);
                prd[i].dbc = htole32((segs[i].ds_len - 1) & AHCI_PRD_MASK);
        }
        slot->dma.nsegs = nsegs;
        bus_dmamap_sync(ch->dma.data_tag, slot->dma.data_map,
            ((slot->ccb->ccb_h.flags & CAM_DIR_IN) ?
            BUS_DMASYNC_PREREAD : BUS_DMASYNC_PREWRITE));
        ahci_execute_transaction(slot);
}

/* Must be called with channel locked. */
static void
ahci_execute_transaction(struct ahci_slot *slot)
{
        struct ahci_channel *ch = slot->ch;
        struct ahci_cmd_tab *ctp;
        struct ahci_cmd_list *clp;
        union ccb *ccb = slot->ccb;
        int port = ccb->ccb_h.target_id & 0x0f;
        int fis_size, i, softreset;
        uint8_t *fis = ch->dma.rfis + 0x40;
        uint8_t val;
        uint16_t cmd_flags;

        /* Get a piece of the workspace for this request */
        ctp = (struct ahci_cmd_tab *)(ch->dma.work + slot->ct_offset);
        /* Setup the FIS for this request */
        if (!(fis_size = ahci_setup_fis(ch, ctp, ccb, slot->slot))) {
                device_printf(ch->dev, "Setting up SATA FIS failed\n");
                ahci_end_transaction(slot, AHCI_ERR_INVALID);
                return;
        }
        /* Setup the command list entry */
        clp = (struct ahci_cmd_list *)
            (ch->dma.work + AHCI_CL_OFFSET + (AHCI_CL_SIZE * slot->slot));
        cmd_flags =
                    (ccb->ccb_h.flags & CAM_DIR_OUT ? AHCI_CMD_WRITE : 0) |
                    (ccb->ccb_h.func_code == XPT_SCSI_IO ?
                     (AHCI_CMD_ATAPI | AHCI_CMD_PREFETCH) : 0) |
                    (fis_size / sizeof(u_int32_t)) |
                    (port << 12);
        clp->prd_length = htole16(slot->dma.nsegs);
        /* Special handling for Soft Reset command. */
        if ((ccb->ccb_h.func_code == XPT_ATA_IO) &&
            (ccb->ataio.cmd.flags & CAM_ATAIO_CONTROL)) {
                if (ccb->ataio.cmd.control & ATA_A_RESET) {
                        softreset = 1;
                        /* Kick controller into sane state */
                        ahci_stop(ch);
                        ahci_clo(ch);
                        ahci_start(ch, 0);
                        cmd_flags |= AHCI_CMD_RESET | AHCI_CMD_CLR_BUSY;
                } else {
                        softreset = 2;
                        /* Prepare FIS receive area for check. */
                        for (i = 0; i < 20; i++)
                                fis[i] = 0xff;
                }
        } else
                softreset = 0;
        clp->bytecount = 0;
        clp->cmd_flags = htole16(cmd_flags);
        clp->cmd_table_phys = htole64(ch->dma.work_bus + slot->ct_offset);
        bus_dmamap_sync(ch->dma.work_tag, ch->dma.work_map,
            BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
        bus_dmamap_sync(ch->dma.rfis_tag, ch->dma.rfis_map,
            BUS_DMASYNC_PREREAD);
        /* Set ACTIVE bit for NCQ commands. */
        if ((ccb->ccb_h.func_code == XPT_ATA_IO) &&
            (ccb->ataio.cmd.flags & CAM_ATAIO_FPDMA)) {
                ATA_OUTL(ch->r_mem, AHCI_P_SACT, 1 << slot->slot);
        }
        /* If FBS is enabled, set PMP port. */
        if (ch->fbs_enabled) {
                ATA_OUTL(ch->r_mem, AHCI_P_FBS, AHCI_P_FBS_EN |
                    (port << AHCI_P_FBS_DEV_SHIFT));
        }
        /* Issue command to the controller. */
        slot->state = AHCI_SLOT_RUNNING;
        ch->rslots |= (1 << slot->slot);
        ATA_OUTL(ch->r_mem, AHCI_P_CI, (1 << slot->slot));
        /* Device reset commands doesn't interrupt. Poll them. */
        if (ccb->ccb_h.func_code == XPT_ATA_IO &&
            (ccb->ataio.cmd.command == ATA_DEVICE_RESET || softreset)) {
                int count, timeout = ccb->ccb_h.timeout * 100;
                enum ahci_err_type et = AHCI_ERR_NONE;

                for (count = 0; count < timeout; count++) {
                        DELAY(10);
                        if (!(ATA_INL(ch->r_mem, AHCI_P_CI) & (1 << slot->slot)))
                                break;
                        if ((ATA_INL(ch->r_mem, AHCI_P_TFD) & ATA_S_ERROR) &&
                            softreset != 1) {
#if 0
                                device_printf(ch->dev,
                                    "Poll error on slot %d, TFD: %04x\n",
                                    slot->slot, ATA_INL(ch->r_mem, AHCI_P_TFD));
#endif
                                et = AHCI_ERR_TFE;
                                break;
                        }
                        /* Workaround for ATI SB600/SB700 chipsets. */
                        if (ccb->ccb_h.target_id == 15 &&
                            (ch->quirks & AHCI_Q_ATI_PMP_BUG) &&
                            (ATA_INL(ch->r_mem, AHCI_P_IS) & AHCI_P_IX_IPM)) {
                                et = AHCI_ERR_TIMEOUT;
                                break;
                        }
                }

                /*
                 * Some Marvell controllers require additional time
                 * after soft reset to work properly. Setup delay
                 * to 50ms after soft reset.
                 */
                if (ch->quirks & AHCI_Q_MRVL_SR_DEL)
                        DELAY(50000);

                /*
                 * Marvell HBAs with non-RAID firmware do not wait for
                 * readiness after soft reset, so we have to wait here.
                 * Marvell RAIDs do not have this problem, but instead
                 * sometimes forget to update FIS receive area, breaking
                 * this wait.
                 */
                if ((ch->quirks & AHCI_Q_NOBSYRES) == 0 &&
                    (ch->quirks & AHCI_Q_ATI_PMP_BUG) == 0 &&
                    softreset == 2 && et == AHCI_ERR_NONE) {
                        for ( ; count < timeout; count++) {
                                bus_dmamap_sync(ch->dma.rfis_tag,
                                    ch->dma.rfis_map, BUS_DMASYNC_POSTREAD);
                                val = fis[2];
                                bus_dmamap_sync(ch->dma.rfis_tag,
                                    ch->dma.rfis_map, BUS_DMASYNC_PREREAD);
                                if ((val & ATA_S_BUSY) == 0)
                                        break;
                                DELAY(10);
                        }
                }

                if (timeout && (count >= timeout)) {
                        device_printf(ch->dev, "Poll timeout on slot %d port %d\n",
                            slot->slot, port);
                        device_printf(ch->dev, "is %08x cs %08x ss %08x "
                            "rs %08x tfd %02x serr %08x cmd %08x\n",
                            ATA_INL(ch->r_mem, AHCI_P_IS),
                            ATA_INL(ch->r_mem, AHCI_P_CI),
                            ATA_INL(ch->r_mem, AHCI_P_SACT), ch->rslots,
                            ATA_INL(ch->r_mem, AHCI_P_TFD),
                            ATA_INL(ch->r_mem, AHCI_P_SERR),
                            ATA_INL(ch->r_mem, AHCI_P_CMD));
                        et = AHCI_ERR_TIMEOUT;
                }

                /* Kick controller into sane state and enable FBS. */
                if (softreset == 2)
                        ch->eslots |= (1 << slot->slot);
                ahci_end_transaction(slot, et);
                return;
        }
        /* Start command execution timeout */
        callout_reset_sbt(&slot->timeout, SBT_1MS * ccb->ccb_h.timeout / 2,
            0, ahci_timeout, slot, 0);
        return;
}

/* Must be called with channel locked. */
static void
ahci_process_timeout(struct ahci_channel *ch)
{
        int i;

        mtx_assert(&ch->mtx, MA_OWNED);
        /* Handle the rest of commands. */
        for (i = 0; i < ch->numslots; i++) {
                /* Do we have a running request on slot? */
                if (ch->slot[i].state < AHCI_SLOT_RUNNING)
                        continue;
                ahci_end_transaction(&ch->slot[i], AHCI_ERR_TIMEOUT);
        }
}

/* Must be called with channel locked. */
static void
ahci_rearm_timeout(struct ahci_channel *ch)
{
        int i;

        mtx_assert(&ch->mtx, MA_OWNED);
        for (i = 0; i < ch->numslots; i++) {
                struct ahci_slot *slot = &ch->slot[i];

                /* Do we have a running request on slot? */
                if (slot->state < AHCI_SLOT_RUNNING)
                        continue;
                if ((ch->toslots & (1 << i)) == 0)
                        continue;
                callout_reset_sbt(&slot->timeout,
                    SBT_1MS * slot->ccb->ccb_h.timeout / 2, 0,
                    ahci_timeout, slot, 0);
        }
}

/* Locked by callout mechanism. */
static void
ahci_timeout(void *arg)
{
        struct ahci_slot *slot = arg;
        struct ahci_channel *ch = slot->ch;
        device_t dev = ch->dev;
        uint32_t sstatus;
        int ccs;
        int i;

        /* Check for stale timeout. */
        if (slot->state < AHCI_SLOT_RUNNING)
                return;

        /* Check if slot was not being executed last time we checked. */
        if (slot->state < AHCI_SLOT_EXECUTING) {
                /* Check if slot started executing. */
                sstatus = ATA_INL(ch->r_mem, AHCI_P_SACT);
                ccs = (ATA_INL(ch->r_mem, AHCI_P_CMD) & AHCI_P_CMD_CCS_MASK)
                    >> AHCI_P_CMD_CCS_SHIFT;
                if ((sstatus & (1 << slot->slot)) != 0 || ccs == slot->slot ||
                    ch->fbs_enabled || ch->wrongccs)
                        slot->state = AHCI_SLOT_EXECUTING;
                else if ((ch->rslots & (1 << ccs)) == 0) {
                        ch->wrongccs = 1;
                        slot->state = AHCI_SLOT_EXECUTING;
                }

                callout_reset_sbt(&slot->timeout,
                    SBT_1MS * slot->ccb->ccb_h.timeout / 2, 0,
                    ahci_timeout, slot, 0);
                return;
        }

        device_printf(dev, "Timeout on slot %d port %d\n",
            slot->slot, slot->ccb->ccb_h.target_id & 0x0f);
        device_printf(dev, "is %08x cs %08x ss %08x rs %08x tfd %02x "
            "serr %08x cmd %08x\n",
            ATA_INL(ch->r_mem, AHCI_P_IS), ATA_INL(ch->r_mem, AHCI_P_CI),
            ATA_INL(ch->r_mem, AHCI_P_SACT), ch->rslots,
            ATA_INL(ch->r_mem, AHCI_P_TFD), ATA_INL(ch->r_mem, AHCI_P_SERR),
            ATA_INL(ch->r_mem, AHCI_P_CMD));

        /* Handle frozen command. */
        if (ch->frozen) {
                union ccb *fccb = ch->frozen;
                ch->frozen = NULL;
                fccb->ccb_h.status = CAM_REQUEUE_REQ | CAM_RELEASE_SIMQ;
                if (!(fccb->ccb_h.status & CAM_DEV_QFRZN)) {
                        xpt_freeze_devq(fccb->ccb_h.path, 1);
                        fccb->ccb_h.status |= CAM_DEV_QFRZN;
                }
                ahci_done(ch, fccb);
        }
        if (!ch->fbs_enabled && !ch->wrongccs) {
                /* Without FBS we know real timeout source. */
                ch->fatalerr = 1;
                /* Handle command with timeout. */
                ahci_end_transaction(&ch->slot[slot->slot], AHCI_ERR_TIMEOUT);
                /* Handle the rest of commands. */
                for (i = 0; i < ch->numslots; i++) {
                        /* Do we have a running request on slot? */
                        if (ch->slot[i].state < AHCI_SLOT_RUNNING)
                                continue;
                        ahci_end_transaction(&ch->slot[i], AHCI_ERR_INNOCENT);
                }
        } else {
                /* With FBS we wait for other commands timeout and pray. */
                if (ch->toslots == 0)
                        xpt_freeze_simq(ch->sim, 1);
                ch->toslots |= (1 << slot->slot);
                if ((ch->rslots & ~ch->toslots) == 0)
                        ahci_process_timeout(ch);
                else
                        device_printf(dev, " ... waiting for slots %08x\n",
                            ch->rslots & ~ch->toslots);
        }
}

/* Must be called with channel locked. */
static void
ahci_end_transaction(struct ahci_slot *slot, enum ahci_err_type et)
{
        struct ahci_channel *ch = slot->ch;
        union ccb *ccb = slot->ccb;
        struct ahci_cmd_list *clp;
        int lastto;
        uint32_t sig;

        bus_dmamap_sync(ch->dma.work_tag, ch->dma.work_map,
            BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
        clp = (struct ahci_cmd_list *)
            (ch->dma.work + AHCI_CL_OFFSET + (AHCI_CL_SIZE * slot->slot));
        /* Read result registers to the result struct
         * May be incorrect if several commands finished same time,
         * so read only when sure or have to.
         */
        if (ccb->ccb_h.func_code == XPT_ATA_IO) {
                struct ata_res *res = &ccb->ataio.res;

                if ((et == AHCI_ERR_TFE) ||
                    (ccb->ataio.cmd.flags & CAM_ATAIO_NEEDRESULT)) {
                        u_int8_t *fis = ch->dma.rfis + 0x40;

                        bus_dmamap_sync(ch->dma.rfis_tag, ch->dma.rfis_map,
                            BUS_DMASYNC_POSTREAD);
                        if (ch->fbs_enabled) {
                                fis += ccb->ccb_h.target_id * 256;
                                res->status = fis[2];
                                res->error = fis[3];
                        } else {
                                uint16_t tfd = ATA_INL(ch->r_mem, AHCI_P_TFD);

                                res->status = tfd;
                                res->error = tfd >> 8;
                        }
                        res->lba_low = fis[4];
                        res->lba_mid = fis[5];
                        res->lba_high = fis[6];
                        res->device = fis[7];
                        res->lba_low_exp = fis[8];
                        res->lba_mid_exp = fis[9];
                        res->lba_high_exp = fis[10];
                        res->sector_count = fis[12];
                        res->sector_count_exp = fis[13];

                        /*
                         * Some weird controllers do not return signature in
                         * FIS receive area. Read it from PxSIG register.
                         */
                        if ((ch->quirks & AHCI_Q_ALTSIG) &&
                            (ccb->ataio.cmd.flags & CAM_ATAIO_CONTROL) &&
                            (ccb->ataio.cmd.control & ATA_A_RESET) == 0) {
                                sig = ATA_INL(ch->r_mem,  AHCI_P_SIG);
                                res->lba_high = sig >> 24;
                                res->lba_mid = sig >> 16;
                                res->lba_low = sig >> 8;
                                res->sector_count = sig;
                        }
                } else
                        bzero(res, sizeof(*res));
                if ((ccb->ataio.cmd.flags & CAM_ATAIO_FPDMA) == 0 &&
                    (ccb->ccb_h.flags & CAM_DIR_MASK) != CAM_DIR_NONE &&
                    (ch->quirks & AHCI_Q_NOCOUNT) == 0) {
                        ccb->ataio.resid =
                            ccb->ataio.dxfer_len - le32toh(clp->bytecount);
                }
        } else {
                if ((ccb->ccb_h.flags & CAM_DIR_MASK) != CAM_DIR_NONE &&
                    (ch->quirks & AHCI_Q_NOCOUNT) == 0) {
                        ccb->csio.resid =
                            ccb->csio.dxfer_len - le32toh(clp->bytecount);
                }
        }
        if ((ccb->ccb_h.flags & CAM_DIR_MASK) != CAM_DIR_NONE) {
                bus_dmamap_sync(ch->dma.data_tag, slot->dma.data_map,
                    (ccb->ccb_h.flags & CAM_DIR_IN) ?
                    BUS_DMASYNC_POSTREAD : BUS_DMASYNC_POSTWRITE);
                bus_dmamap_unload(ch->dma.data_tag, slot->dma.data_map);
        }
        if (et != AHCI_ERR_NONE)
                ch->eslots |= (1 << slot->slot);
        /* In case of error, freeze device for proper recovery. */
        if ((et != AHCI_ERR_NONE) && (!ch->recoverycmd) &&
            !(ccb->ccb_h.status & CAM_DEV_QFRZN)) {
                xpt_freeze_devq(ccb->ccb_h.path, 1);
                ccb->ccb_h.status |= CAM_DEV_QFRZN;
        }
        /* Set proper result status. */
        ccb->ccb_h.status &= ~CAM_STATUS_MASK;
        switch (et) {
        case AHCI_ERR_NONE:
                ccb->ccb_h.status |= CAM_REQ_CMP;
                if (ccb->ccb_h.func_code == XPT_SCSI_IO)
                        ccb->csio.scsi_status = SCSI_STATUS_OK;
                break;
        case AHCI_ERR_INVALID:
                ch->fatalerr = 1;
                ccb->ccb_h.status |= CAM_REQ_INVALID;
                break;
        case AHCI_ERR_INNOCENT:
                ccb->ccb_h.status |= CAM_REQUEUE_REQ;
                break;
        case AHCI_ERR_TFE:
        case AHCI_ERR_NCQ:
                if (ccb->ccb_h.func_code == XPT_SCSI_IO) {
                        ccb->ccb_h.status |= CAM_SCSI_STATUS_ERROR;
                        ccb->csio.scsi_status = SCSI_STATUS_CHECK_COND;
                } else {
                        ccb->ccb_h.status |= CAM_ATA_STATUS_ERROR;
                }
                break;
        case AHCI_ERR_SATA:
                ch->fatalerr = 1;
                if (!ch->recoverycmd) {
                        xpt_freeze_simq(ch->sim, 1);
                        ccb->ccb_h.status &= ~CAM_STATUS_MASK;
                        ccb->ccb_h.status |= CAM_RELEASE_SIMQ;
                }
                ccb->ccb_h.status |= CAM_UNCOR_PARITY;
                break;
        case AHCI_ERR_TIMEOUT:
                if (!ch->recoverycmd) {
                        xpt_freeze_simq(ch->sim, 1);
                        ccb->ccb_h.status &= ~CAM_STATUS_MASK;
                        ccb->ccb_h.status |= CAM_RELEASE_SIMQ;
                }
                ccb->ccb_h.status |= CAM_CMD_TIMEOUT;
                break;
        default:
                ch->fatalerr = 1;
                ccb->ccb_h.status |= CAM_REQ_CMP_ERR;
        }
        /* Free slot. */
        ch->oslots &= ~(1 << slot->slot);
        ch->rslots &= ~(1 << slot->slot);
        ch->aslots &= ~(1 << slot->slot);
        slot->state = AHCI_SLOT_EMPTY;
        slot->ccb = NULL;
        /* Update channel stats. */
        ch->numrslots--;
        ch->numrslotspd[ccb->ccb_h.target_id]--;
        if ((ccb->ccb_h.func_code == XPT_ATA_IO) &&
            (ccb->ataio.cmd.flags & CAM_ATAIO_FPDMA)) {
                ch->numtslots--;
                ch->numtslotspd[ccb->ccb_h.target_id]--;
        }
        /* Cancel timeout state if request completed normally. */
        if (et != AHCI_ERR_TIMEOUT) {
                lastto = (ch->toslots == (1 << slot->slot));
                ch->toslots &= ~(1 << slot->slot);
                if (lastto)
                        xpt_release_simq(ch->sim, TRUE);
        }
        /* If it was first request of reset sequence and there is no error,
         * proceed to second request. */
        if ((ccb->ccb_h.func_code == XPT_ATA_IO) &&
            (ccb->ataio.cmd.flags & CAM_ATAIO_CONTROL) &&
            (ccb->ataio.cmd.control & ATA_A_RESET) &&
            et == AHCI_ERR_NONE) {
                ccb->ataio.cmd.control &= ~ATA_A_RESET;
                ahci_begin_transaction(ch, ccb);
                return;
        }
        /* If it was our READ LOG command - process it. */
        if (ccb->ccb_h.recovery_type == RECOVERY_READ_LOG) {
                ahci_process_read_log(ch, ccb);
        /* If it was our REQUEST SENSE command - process it. */
        } else if (ccb->ccb_h.recovery_type == RECOVERY_REQUEST_SENSE) {
                ahci_process_request_sense(ch, ccb);
        /* If it was NCQ or ATAPI command error, put result on hold. */
        } else if (et == AHCI_ERR_NCQ ||
            ((ccb->ccb_h.status & CAM_STATUS_MASK) == CAM_SCSI_STATUS_ERROR &&
             (ccb->ccb_h.flags & CAM_DIS_AUTOSENSE) == 0)) {
                ch->hold[slot->slot] = ccb;
                ch->numhslots++;
        } else
                ahci_done(ch, ccb);
        /* If we have no other active commands, ... */
        if (ch->rslots == 0) {
                /* if there was fatal error - reset port. */
                if (ch->toslots != 0 || ch->fatalerr) {
                        ahci_reset(ch);
                } else {
                        /* if we have slots in error, we can reinit port. */
                        if (ch->eslots != 0) {
                                ahci_stop(ch);
                                ahci_clo(ch);
                                ahci_start(ch, 1);
                        }
                        /* if there commands on hold, we can do READ LOG. */
                        if (!ch->recoverycmd && ch->numhslots)
                                ahci_issue_recovery(ch);
                }
        /* If all the rest of commands are in timeout - give them chance. */
        } else if ((ch->rslots & ~ch->toslots) == 0 &&
            et != AHCI_ERR_TIMEOUT)
                ahci_rearm_timeout(ch);
        /* Unfreeze frozen command. */
        if (ch->frozen && !ahci_check_collision(ch, ch->frozen)) {
                union ccb *fccb = ch->frozen;
                ch->frozen = NULL;
                ahci_begin_transaction(ch, fccb);
                xpt_release_simq(ch->sim, TRUE);
        }
        /* Start PM timer. */
        if (ch->numrslots == 0 && ch->pm_level > 3 &&
            (ch->curr[ch->pm_present ? 15 : 0].caps & CTS_SATA_CAPS_D_PMREQ)) {
                callout_schedule(&ch->pm_timer,
                    (ch->pm_level == 4) ? hz / 1000 : hz / 8);
        }
}

static void
ahci_issue_recovery(struct ahci_channel *ch)
{
        union ccb *ccb;
        struct ccb_ataio *ataio;
        struct ccb_scsiio *csio;
        int i;

        /* Find some held command. */
        for (i = 0; i < ch->numslots; i++) {
                if (ch->hold[i])
                        break;
        }
        ccb = xpt_alloc_ccb_nowait();
        if (ccb == NULL) {
                device_printf(ch->dev, "Unable to allocate recovery command\n");
completeall:
                /* We can't do anything -- complete held commands. */
                for (i = 0; i < ch->numslots; i++) {
                        if (ch->hold[i] == NULL)
                                continue;
                        ch->hold[i]->ccb_h.status &= ~CAM_STATUS_MASK;
                        ch->hold[i]->ccb_h.status |= CAM_RESRC_UNAVAIL;
                        ahci_done(ch, ch->hold[i]);
                        ch->hold[i] = NULL;
                        ch->numhslots--;
                }
                ahci_reset(ch);
                return;
        }
        xpt_setup_ccb(&ccb->ccb_h, ch->hold[i]->ccb_h.path,
            ch->hold[i]->ccb_h.pinfo.priority);
        if (ch->hold[i]->ccb_h.func_code == XPT_ATA_IO) {
                /* READ LOG */
                ccb->ccb_h.recovery_type = RECOVERY_READ_LOG;
                ccb->ccb_h.func_code = XPT_ATA_IO;
                ccb->ccb_h.flags = CAM_DIR_IN;
                ccb->ccb_h.timeout = 1000;      /* 1s should be enough. */
                ataio = &ccb->ataio;
                ataio->data_ptr = malloc(512, M_AHCI, M_NOWAIT);
                if (ataio->data_ptr == NULL) {
                        xpt_free_ccb(ccb);
                        device_printf(ch->dev,
                            "Unable to allocate memory for READ LOG command\n");
                        goto completeall;
                }
                ataio->dxfer_len = 512;
                bzero(&ataio->cmd, sizeof(ataio->cmd));
                ataio->cmd.flags = CAM_ATAIO_48BIT;
                ataio->cmd.command = 0x2F;      /* READ LOG EXT */
                ataio->cmd.sector_count = 1;
                ataio->cmd.sector_count_exp = 0;
                ataio->cmd.lba_low = 0x10;
                ataio->cmd.lba_mid = 0;
                ataio->cmd.lba_mid_exp = 0;
        } else {
                /* REQUEST SENSE */
                ccb->ccb_h.recovery_type = RECOVERY_REQUEST_SENSE;
                ccb->ccb_h.recovery_slot = i;
                ccb->ccb_h.func_code = XPT_SCSI_IO;
                ccb->ccb_h.flags = CAM_DIR_IN;
                ccb->ccb_h.status = 0;
                ccb->ccb_h.timeout = 1000;      /* 1s should be enough. */
                csio = &ccb->csio;
                csio->data_ptr = (void *)&ch->hold[i]->csio.sense_data;
                csio->dxfer_len = ch->hold[i]->csio.sense_len;
                csio->cdb_len = 6;
                bzero(&csio->cdb_io, sizeof(csio->cdb_io));
                csio->cdb_io.cdb_bytes[0] = 0x03;
                csio->cdb_io.cdb_bytes[4] = csio->dxfer_len;
        }
        /* Freeze SIM while doing recovery. */
        ch->recoverycmd = 1;
        xpt_freeze_simq(ch->sim, 1);
        ahci_begin_transaction(ch, ccb);
}

static void
ahci_process_read_log(struct ahci_channel *ch, union ccb *ccb)
{
        uint8_t *data;
        struct ata_res *res;
        int i;

        ch->recoverycmd = 0;

        data = ccb->ataio.data_ptr;
        if ((ccb->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP &&
            (data[0] & 0x80) == 0) {
                for (i = 0; i < ch->numslots; i++) {
                        if (!ch->hold[i])
                                continue;
                        if (ch->hold[i]->ccb_h.func_code != XPT_ATA_IO)
                                continue;
                        if ((data[0] & 0x1F) == i) {
                                res = &ch->hold[i]->ataio.res;
                                res->status = data[2];
                                res->error = data[3];
                                res->lba_low = data[4];
                                res->lba_mid = data[5];
                                res->lba_high = data[6];
                                res->device = data[7];
                                res->lba_low_exp = data[8];
                                res->lba_mid_exp = data[9];
                                res->lba_high_exp = data[10];
                                res->sector_count = data[12];
                                res->sector_count_exp = data[13];
                        } else {
                                ch->hold[i]->ccb_h.status &= ~CAM_STATUS_MASK;
                                ch->hold[i]->ccb_h.status |= CAM_REQUEUE_REQ;
                        }
                        ahci_done(ch, ch->hold[i]);
                        ch->hold[i] = NULL;
                        ch->numhslots--;
                }
        } else {
                if ((ccb->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP)
                        device_printf(ch->dev, "Error while READ LOG EXT\n");
                else if ((data[0] & 0x80) == 0) {
                        device_printf(ch->dev, "Non-queued command error in READ LOG EXT\n");
                }
                for (i = 0; i < ch->numslots; i++) {
                        if (!ch->hold[i])
                                continue;
                        if (ch->hold[i]->ccb_h.func_code != XPT_ATA_IO)
                                continue;
                        ahci_done(ch, ch->hold[i]);
                        ch->hold[i] = NULL;
                        ch->numhslots--;
                }
        }
        free(ccb->ataio.data_ptr, M_AHCI);
        xpt_free_ccb(ccb);
        xpt_release_simq(ch->sim, TRUE);
}

static void
ahci_process_request_sense(struct ahci_channel *ch, union ccb *ccb)
{
        int i;

        ch->recoverycmd = 0;

        i = ccb->ccb_h.recovery_slot;
        if ((ccb->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP) {
                ch->hold[i]->ccb_h.status |= CAM_AUTOSNS_VALID;
        } else {
                ch->hold[i]->ccb_h.status &= ~CAM_STATUS_MASK;
                ch->hold[i]->ccb_h.status |= CAM_AUTOSENSE_FAIL;
        }
        ahci_done(ch, ch->hold[i]);
        ch->hold[i] = NULL;
        ch->numhslots--;
        xpt_free_ccb(ccb);
        xpt_release_simq(ch->sim, TRUE);
}

static void
ahci_start(struct ahci_channel *ch, int fbs)
{
        u_int32_t cmd;

        /* Run the channel start callback, if any. */
        if (ch->start)
                ch->start(ch);

        /* Clear SATA error register */
        ATA_OUTL(ch->r_mem, AHCI_P_SERR, 0xFFFFFFFF);
        /* Clear any interrupts pending on this channel */
        ATA_OUTL(ch->r_mem, AHCI_P_IS, 0xFFFFFFFF);
        /* Configure FIS-based switching if supported. */
        if (ch->chcaps & AHCI_P_CMD_FBSCP) {
                ch->fbs_enabled = (fbs && ch->pm_present) ? 1 : 0;
                ATA_OUTL(ch->r_mem, AHCI_P_FBS,
                    ch->fbs_enabled ? AHCI_P_FBS_EN : 0);
        }
        /* Start operations on this channel */
        cmd = ATA_INL(ch->r_mem, AHCI_P_CMD);
        cmd &= ~AHCI_P_CMD_PMA;
        ATA_OUTL(ch->r_mem, AHCI_P_CMD, cmd | AHCI_P_CMD_ST |
            (ch->pm_present ? AHCI_P_CMD_PMA : 0));
}

static void
ahci_stop(struct ahci_channel *ch)
{
        u_int32_t cmd;
        int timeout;

        /* Kill all activity on this channel */
        cmd = ATA_INL(ch->r_mem, AHCI_P_CMD);
        ATA_OUTL(ch->r_mem, AHCI_P_CMD, cmd & ~AHCI_P_CMD_ST);
        /* Wait for activity stop. */
        timeout = 0;
        do {
                DELAY(10);
                if (timeout++ > 50000) {
                        device_printf(ch->dev, "stopping AHCI engine failed\n");
                        break;
                }
        } while (ATA_INL(ch->r_mem, AHCI_P_CMD) & AHCI_P_CMD_CR);
        ch->eslots = 0;
}

static void
ahci_clo(struct ahci_channel *ch)
{
        u_int32_t cmd;
        int timeout;

        /* Issue Command List Override if supported */ 
        if (ch->caps & AHCI_CAP_SCLO) {
                cmd = ATA_INL(ch->r_mem, AHCI_P_CMD);
                cmd |= AHCI_P_CMD_CLO;
                ATA_OUTL(ch->r_mem, AHCI_P_CMD, cmd);
                timeout = 0;
                do {
                        DELAY(10);
                        if (timeout++ > 50000) {
                            device_printf(ch->dev, "executing CLO failed\n");
                            break;
                        }
                } while (ATA_INL(ch->r_mem, AHCI_P_CMD) & AHCI_P_CMD_CLO);
        }
}

static void
ahci_stop_fr(struct ahci_channel *ch)
{
        u_int32_t cmd;
        int timeout;

        /* Kill all FIS reception on this channel */
        cmd = ATA_INL(ch->r_mem, AHCI_P_CMD);
        ATA_OUTL(ch->r_mem, AHCI_P_CMD, cmd & ~AHCI_P_CMD_FRE);
        /* Wait for FIS reception stop. */
        timeout = 0;
        do {
                DELAY(10);
                if (timeout++ > 50000) {
                        device_printf(ch->dev, "stopping AHCI FR engine failed\n");
                        break;
                }
        } while (ATA_INL(ch->r_mem, AHCI_P_CMD) & AHCI_P_CMD_FR);
}

static void
ahci_start_fr(struct ahci_channel *ch)
{
        u_int32_t cmd;

        /* Start FIS reception on this channel */
        cmd = ATA_INL(ch->r_mem, AHCI_P_CMD);
        ATA_OUTL(ch->r_mem, AHCI_P_CMD, cmd | AHCI_P_CMD_FRE);
}

static int
ahci_wait_ready(struct ahci_channel *ch, int t, int t0)
{
        int timeout = 0;
        uint32_t val;

        while ((val = ATA_INL(ch->r_mem, AHCI_P_TFD)) &
            (ATA_S_BUSY | ATA_S_DRQ)) {
                if (timeout > t) {
                        if (t != 0) {
                                device_printf(ch->dev,
                                    "AHCI reset: device not ready after %dms "
                                    "(tfd = %08x)\n",
                                    MAX(t, 0) + t0, val);
                        }
                        return (EBUSY);
                }
                DELAY(1000);
                timeout++;
        }
        if (bootverbose)
                device_printf(ch->dev, "AHCI reset: device ready after %dms\n",
                    timeout + t0);
        return (0);
}

static void
ahci_reset_to(void *arg)
{
        struct ahci_channel *ch = arg;

        if (ch->resetting == 0)
                return;
        ch->resetting--;
        if (ahci_wait_ready(ch, ch->resetting == 0 ? -1 : 0,
            (310 - ch->resetting) * 100) == 0) {
                ch->resetting = 0;
                ahci_start(ch, 1);
                xpt_release_simq(ch->sim, TRUE);
                return;
        }
        if (ch->resetting == 0) {
                ahci_clo(ch);
                ahci_start(ch, 1);
                xpt_release_simq(ch->sim, TRUE);
                return;
        }
        callout_schedule(&ch->reset_timer, hz / 10);
}

static void
ahci_reset(struct ahci_channel *ch)
{
        struct ahci_controller *ctlr = device_get_softc(device_get_parent(ch->dev));
        int i;

        xpt_freeze_simq(ch->sim, 1);
        if (bootverbose)
                device_printf(ch->dev, "AHCI reset...\n");
        /* Forget about previous reset. */
        if (ch->resetting) {
                ch->resetting = 0;
                callout_stop(&ch->reset_timer);
                xpt_release_simq(ch->sim, TRUE);
        }
        /* Requeue freezed command. */
        if (ch->frozen) {
                union ccb *fccb = ch->frozen;
                ch->frozen = NULL;
                fccb->ccb_h.status = CAM_REQUEUE_REQ | CAM_RELEASE_SIMQ;
                if (!(fccb->ccb_h.status & CAM_DEV_QFRZN)) {
                        xpt_freeze_devq(fccb->ccb_h.path, 1);
                        fccb->ccb_h.status |= CAM_DEV_QFRZN;
                }
                ahci_done(ch, fccb);
        }
        /* Kill the engine and requeue all running commands. */
        ahci_stop(ch);
        for (i = 0; i < ch->numslots; i++) {
                /* Do we have a running request on slot? */
                if (ch->slot[i].state < AHCI_SLOT_RUNNING)
                        continue;
                /* XXX; Commands in loading state. */
                ahci_end_transaction(&ch->slot[i], AHCI_ERR_INNOCENT);
        }
        for (i = 0; i < ch->numslots; i++) {
                if (!ch->hold[i])
                        continue;
                ahci_done(ch, ch->hold[i]);
                ch->hold[i] = NULL;
                ch->numhslots--;
        }
        if (ch->toslots != 0)
                xpt_release_simq(ch->sim, TRUE);
        ch->eslots = 0;
        ch->toslots = 0;
        ch->wrongccs = 0;
        ch->fatalerr = 0;
        /* Tell the XPT about the event */
        xpt_async(AC_BUS_RESET, ch->path, NULL);
        /* Disable port interrupts */
        ATA_OUTL(ch->r_mem, AHCI_P_IE, 0);
        /* Reset and reconnect PHY, */
        if (!ahci_sata_phy_reset(ch)) {
                if (bootverbose)
                        device_printf(ch->dev,
                            "AHCI reset: device not found\n");
                ch->devices = 0;
                /* Enable wanted port interrupts */
                ATA_OUTL(ch->r_mem, AHCI_P_IE,
                    (((ch->pm_level != 0) ? AHCI_P_IX_CPD | AHCI_P_IX_MP : 0) |
                     AHCI_P_IX_PRC | AHCI_P_IX_PC));
                xpt_release_simq(ch->sim, TRUE);
                return;
        }
        if (bootverbose)
                device_printf(ch->dev, "AHCI reset: device found\n");
        /* Wait for clearing busy status. */
        if (ahci_wait_ready(ch, dumping ? 31000 : 0, 0)) {
                if (dumping)
                        ahci_clo(ch);
                else
                        ch->resetting = 310;
        }
        ch->devices = 1;
        /* Enable wanted port interrupts */
        ATA_OUTL(ch->r_mem, AHCI_P_IE,
             (((ch->pm_level != 0) ? AHCI_P_IX_CPD | AHCI_P_IX_MP : 0) |
              AHCI_P_IX_TFE | AHCI_P_IX_HBF |
              AHCI_P_IX_HBD | AHCI_P_IX_IF | AHCI_P_IX_OF |
              ((ch->pm_level == 0) ? AHCI_P_IX_PRC : 0) | AHCI_P_IX_PC |
              AHCI_P_IX_DP | AHCI_P_IX_UF | (ctlr->ccc ? 0 : AHCI_P_IX_SDB) |
              AHCI_P_IX_DS | AHCI_P_IX_PS | (ctlr->ccc ? 0 : AHCI_P_IX_DHR)));
        if (ch->resetting)
                callout_reset(&ch->reset_timer, hz / 10, ahci_reset_to, ch);
        else {
                ahci_start(ch, 1);
                xpt_release_simq(ch->sim, TRUE);
        }
}

static int
ahci_setup_fis(struct ahci_channel *ch, struct ahci_cmd_tab *ctp, union ccb *ccb, int tag)
{
        u_int8_t *fis = &ctp->cfis[0];

        bzero(fis, 20);
        fis[0] = 0x27;                  /* host to device */
        fis[1] = (ccb->ccb_h.target_id & 0x0f);
        if (ccb->ccb_h.func_code == XPT_SCSI_IO) {
                fis[1] |= 0x80;
                fis[2] = ATA_PACKET_CMD;
                if ((ccb->ccb_h.flags & CAM_DIR_MASK) != CAM_DIR_NONE &&
                    ch->curr[ccb->ccb_h.target_id].mode >= ATA_DMA)
                        fis[3] = ATA_F_DMA;
                else {
                        fis[5] = ccb->csio.dxfer_len;
                        fis[6] = ccb->csio.dxfer_len >> 8;
                }
                fis[7] = ATA_D_LBA;
                fis[15] = ATA_A_4BIT;
                bcopy((ccb->ccb_h.flags & CAM_CDB_POINTER) ?
                    ccb->csio.cdb_io.cdb_ptr : ccb->csio.cdb_io.cdb_bytes,
                    ctp->acmd, ccb->csio.cdb_len);
                bzero(ctp->acmd + ccb->csio.cdb_len, 32 - ccb->csio.cdb_len);
        } else if ((ccb->ataio.cmd.flags & CAM_ATAIO_CONTROL) == 0) {
                fis[1] |= 0x80;
                fis[2] = ccb->ataio.cmd.command;
                fis[3] = ccb->ataio.cmd.features;
                fis[4] = ccb->ataio.cmd.lba_low;
                fis[5] = ccb->ataio.cmd.lba_mid;
                fis[6] = ccb->ataio.cmd.lba_high;
                fis[7] = ccb->ataio.cmd.device;
                fis[8] = ccb->ataio.cmd.lba_low_exp;
                fis[9] = ccb->ataio.cmd.lba_mid_exp;
                fis[10] = ccb->ataio.cmd.lba_high_exp;
                fis[11] = ccb->ataio.cmd.features_exp;
                fis[12] = ccb->ataio.cmd.sector_count;
                if (ccb->ataio.cmd.flags & CAM_ATAIO_FPDMA) {
                        fis[12] &= 0x07;
                        fis[12] |= tag << 3;
                }
                fis[13] = ccb->ataio.cmd.sector_count_exp;
                if (ccb->ataio.ata_flags & ATA_FLAG_ICC)
                        fis[14] = ccb->ataio.icc;
                fis[15] = ATA_A_4BIT;
                if (ccb->ataio.ata_flags & ATA_FLAG_AUX) {
                        fis[16] =  ccb->ataio.aux        & 0xff;
                        fis[17] = (ccb->ataio.aux >>  8) & 0xff;
                        fis[18] = (ccb->ataio.aux >> 16) & 0xff;
                        fis[19] = (ccb->ataio.aux >> 24) & 0xff;
                }
        } else {
                fis[15] = ccb->ataio.cmd.control;
        }
        return (20);
}

static int
ahci_sata_connect(struct ahci_channel *ch)
{
        u_int32_t status;
        int timeout, timeoutslot, found = 0;

        /*
         * Wait for "connect well", up to 100ms by default and
         * up to 500ms for devices with the SLOWDEV quirk.
         */
        timeoutslot = ((ch->quirks & AHCI_Q_SLOWDEV) ? 5000 : 1000);
        for (timeout = 0; timeout < timeoutslot; timeout++) {
                status = ATA_INL(ch->r_mem, AHCI_P_SSTS);
                if ((status & ATA_SS_DET_MASK) != ATA_SS_DET_NO_DEVICE)
                        found = 1;
                if (((status & ATA_SS_DET_MASK) == ATA_SS_DET_PHY_ONLINE) &&
                    ((status & ATA_SS_SPD_MASK) != ATA_SS_SPD_NO_SPEED) &&
                    ((status & ATA_SS_IPM_MASK) == ATA_SS_IPM_ACTIVE))
                        break;
                if ((status & ATA_SS_DET_MASK) == ATA_SS_DET_PHY_OFFLINE) {
                        if (bootverbose) {
                                device_printf(ch->dev, "SATA offline status=%08x\n",
                                    status);
                        }
                        return (0);
                }
                if (found == 0 && timeout >= 100)
                        break;
                DELAY(100);
        }
        if (timeout >= timeoutslot || !found) {
                if (bootverbose) {
                        device_printf(ch->dev,
                            "SATA connect timeout time=%dus status=%08x\n",
                            timeout * 100, status);
                }
                return (0);
        }
        if (bootverbose) {
                device_printf(ch->dev, "SATA connect time=%dus status=%08x\n",
                    timeout * 100, status);
        }
        /* Clear SATA error register */
        ATA_OUTL(ch->r_mem, AHCI_P_SERR, 0xffffffff);
        return (1);
}

static int
ahci_sata_phy_reset(struct ahci_channel *ch)
{
        int sata_rev;
        uint32_t val, detval;

        if (ch->listening) {
                val = ATA_INL(ch->r_mem, AHCI_P_CMD);
                val |= AHCI_P_CMD_SUD;
                ATA_OUTL(ch->r_mem, AHCI_P_CMD, val);
                ch->listening = 0;
        }
        sata_rev = ch->user[ch->pm_present ? 15 : 0].revision;
        if (sata_rev == 1)
                val = ATA_SC_SPD_SPEED_GEN1;
        else if (sata_rev == 2)
                val = ATA_SC_SPD_SPEED_GEN2;
        else if (sata_rev == 3)
                val = ATA_SC_SPD_SPEED_GEN3;
        else
                val = 0;
        detval = ahci_ch_detval(ch, ATA_SC_DET_RESET);
        ATA_OUTL(ch->r_mem, AHCI_P_SCTL,
            detval | val |
            ATA_SC_IPM_DIS_PARTIAL | ATA_SC_IPM_DIS_SLUMBER);
        DELAY(1000);
        detval = ahci_ch_detval(ch, ATA_SC_DET_IDLE);
        ATA_OUTL(ch->r_mem, AHCI_P_SCTL,
            detval | val | ((ch->pm_level > 0) ? 0 :
            (ATA_SC_IPM_DIS_PARTIAL | ATA_SC_IPM_DIS_SLUMBER)));
        if (!ahci_sata_connect(ch)) {
                if (ch->caps & AHCI_CAP_SSS) {
                        val = ATA_INL(ch->r_mem, AHCI_P_CMD);
                        val &= ~AHCI_P_CMD_SUD;
                        ATA_OUTL(ch->r_mem, AHCI_P_CMD, val);
                        ch->listening = 1;
                } else if (ch->pm_level > 0)
                        ATA_OUTL(ch->r_mem, AHCI_P_SCTL, ATA_SC_DET_DISABLE);
                return (0);
        }
        return (1);
}

static int
ahci_check_ids(struct ahci_channel *ch, union ccb *ccb)
{

        if (ccb->ccb_h.target_id > ((ch->caps & AHCI_CAP_SPM) ? 15 : 0)) {
                ccb->ccb_h.status = CAM_TID_INVALID;
                ahci_done(ch, ccb);
                return (-1);
        }
        if (ccb->ccb_h.target_lun != 0) {
                ccb->ccb_h.status = CAM_LUN_INVALID;
                ahci_done(ch, ccb);
                return (-1);
        }
        return (0);
}

static void
ahciaction(struct cam_sim *sim, union ccb *ccb)
{
        struct ahci_channel *ch;

        CAM_DEBUG(ccb->ccb_h.path, CAM_DEBUG_TRACE, ("ahciaction func_code=%x\n",
            ccb->ccb_h.func_code));

        ch = (struct ahci_channel *)cam_sim_softc(sim);
        switch (ccb->ccb_h.func_code) {
        /* Common cases first */
        case XPT_ATA_IO:        /* Execute the requested I/O operation */
        case XPT_SCSI_IO:
                if (ahci_check_ids(ch, ccb))
                        return;
                if (ch->devices == 0 ||
                    (ch->pm_present == 0 &&
                     ccb->ccb_h.target_id > 0 && ccb->ccb_h.target_id < 15)) {
                        ccb->ccb_h.status = CAM_SEL_TIMEOUT;
                        break;
                }
                ccb->ccb_h.recovery_type = RECOVERY_NONE;
                /* Check for command collision. */
                if (ahci_check_collision(ch, ccb)) {
                        /* Freeze command. */
                        ch->frozen = ccb;
                        /* We have only one frozen slot, so freeze simq also. */
                        xpt_freeze_simq(ch->sim, 1);
                        return;
                }
                ahci_begin_transaction(ch, ccb);
                return;
        case XPT_ABORT:                 /* Abort the specified CCB */
                /* XXX Implement */
                ccb->ccb_h.status = CAM_REQ_INVALID;
                break;
        case XPT_SET_TRAN_SETTINGS:
        {
                struct  ccb_trans_settings *cts = &ccb->cts;
                struct  ahci_device *d; 

                if (ahci_check_ids(ch, ccb))
                        return;
                if (cts->type == CTS_TYPE_CURRENT_SETTINGS)
                        d = &ch->curr[ccb->ccb_h.target_id];
                else
                        d = &ch->user[ccb->ccb_h.target_id];
                if (cts->xport_specific.sata.valid & CTS_SATA_VALID_REVISION)
                        d->revision = cts->xport_specific.sata.revision;
                if (cts->xport_specific.sata.valid & CTS_SATA_VALID_MODE)
                        d->mode = cts->xport_specific.sata.mode;
                if (cts->xport_specific.sata.valid & CTS_SATA_VALID_BYTECOUNT)
                        d->bytecount = min(8192, cts->xport_specific.sata.bytecount);
                if (cts->xport_specific.sata.valid & CTS_SATA_VALID_TAGS)
                        d->tags = min(ch->numslots, cts->xport_specific.sata.tags);
                if (cts->xport_specific.sata.valid & CTS_SATA_VALID_PM)
                        ch->pm_present = cts->xport_specific.sata.pm_present;
                if (cts->xport_specific.sata.valid & CTS_SATA_VALID_ATAPI)
                        d->atapi = cts->xport_specific.sata.atapi;
                if (cts->xport_specific.sata.valid & CTS_SATA_VALID_CAPS)
                        d->caps = cts->xport_specific.sata.caps;
                ccb->ccb_h.status = CAM_REQ_CMP;
                break;
        }
        case XPT_GET_TRAN_SETTINGS:
        /* Get default/user set transfer settings for the target */
        {
                struct  ccb_trans_settings *cts = &ccb->cts;
                struct  ahci_device *d;
                uint32_t status;

                if (ahci_check_ids(ch, ccb))
                        return;
                if (cts->type == CTS_TYPE_CURRENT_SETTINGS)
                        d = &ch->curr[ccb->ccb_h.target_id];
                else
                        d = &ch->user[ccb->ccb_h.target_id];
                cts->protocol = PROTO_UNSPECIFIED;
                cts->protocol_version = PROTO_VERSION_UNSPECIFIED;
                cts->transport = XPORT_SATA;
                cts->transport_version = XPORT_VERSION_UNSPECIFIED;
                cts->proto_specific.valid = 0;
                cts->xport_specific.sata.valid = 0;
                if (cts->type == CTS_TYPE_CURRENT_SETTINGS &&
                    (ccb->ccb_h.target_id == 15 ||
                    (ccb->ccb_h.target_id == 0 && !ch->pm_present))) {
                        status = ATA_INL(ch->r_mem, AHCI_P_SSTS) & ATA_SS_SPD_MASK;
                        if (status & 0x0f0) {
                                cts->xport_specific.sata.revision =
                                    (status & 0x0f0) >> 4;
                                cts->xport_specific.sata.valid |=
                                    CTS_SATA_VALID_REVISION;
                        }
                        cts->xport_specific.sata.caps = d->caps & CTS_SATA_CAPS_D;
                        if (ch->pm_level) {
                                if (ch->caps & (AHCI_CAP_PSC | AHCI_CAP_SSC))
                                        cts->xport_specific.sata.caps |= CTS_SATA_CAPS_H_PMREQ;
                                if (ch->caps2 & AHCI_CAP2_APST)
                                        cts->xport_specific.sata.caps |= CTS_SATA_CAPS_H_APST;
                        }
                        if ((ch->caps & AHCI_CAP_SNCQ) &&
                            (ch->quirks & AHCI_Q_NOAA) == 0)
                                cts->xport_specific.sata.caps |= CTS_SATA_CAPS_H_DMAAA;
                        cts->xport_specific.sata.caps |= CTS_SATA_CAPS_H_AN;
                        cts->xport_specific.sata.caps &=
                            ch->user[ccb->ccb_h.target_id].caps;
                        cts->xport_specific.sata.valid |= CTS_SATA_VALID_CAPS;
                } else {
                        cts->xport_specific.sata.revision = d->revision;
                        cts->xport_specific.sata.valid |= CTS_SATA_VALID_REVISION;
                        cts->xport_specific.sata.caps = d->caps;
                        cts->xport_specific.sata.valid |= CTS_SATA_VALID_CAPS;
                }
                cts->xport_specific.sata.mode = d->mode;
                cts->xport_specific.sata.valid |= CTS_SATA_VALID_MODE;
                cts->xport_specific.sata.bytecount = d->bytecount;
                cts->xport_specific.sata.valid |= CTS_SATA_VALID_BYTECOUNT;
                cts->xport_specific.sata.pm_present = ch->pm_present;
                cts->xport_specific.sata.valid |= CTS_SATA_VALID_PM;
                cts->xport_specific.sata.tags = d->tags;
                cts->xport_specific.sata.valid |= CTS_SATA_VALID_TAGS;
                cts->xport_specific.sata.atapi = d->atapi;
                cts->xport_specific.sata.valid |= CTS_SATA_VALID_ATAPI;
                ccb->ccb_h.status = CAM_REQ_CMP;
                break;
        }
        case XPT_RESET_BUS:             /* Reset the specified SCSI bus */
        case XPT_RESET_DEV:     /* Bus Device Reset the specified SCSI device */
                ahci_reset(ch);
                ccb->ccb_h.status = CAM_REQ_CMP;
                break;
        case XPT_TERM_IO:               /* Terminate the I/O process */
                /* XXX Implement */
                ccb->ccb_h.status = CAM_REQ_INVALID;
                break;
        case XPT_PATH_INQ:              /* Path routing inquiry */
        {
                struct ccb_pathinq *cpi = &ccb->cpi;

                cpi->version_num = 1; /* XXX??? */
                cpi->hba_inquiry = PI_SDTR_ABLE;
                if (ch->caps & AHCI_CAP_SNCQ)
                        cpi->hba_inquiry |= PI_TAG_ABLE;
                if (ch->caps & AHCI_CAP_SPM)
                        cpi->hba_inquiry |= PI_SATAPM;
                cpi->target_sprt = 0;
                cpi->hba_misc = PIM_SEQSCAN | PIM_UNMAPPED;
                if ((ch->quirks & AHCI_Q_NOAUX) == 0)
                        cpi->hba_misc |= PIM_ATA_EXT;
                cpi->hba_eng_cnt = 0;
                if (ch->caps & AHCI_CAP_SPM)
                        cpi->max_target = 15;
                else
                        cpi->max_target = 0;
                cpi->max_lun = 0;
                cpi->initiator_id = 0;
                cpi->bus_id = cam_sim_bus(sim);
                cpi->base_transfer_speed = 150000;
                strlcpy(cpi->sim_vid, "FreeBSD", SIM_IDLEN);
                strlcpy(cpi->hba_vid, "AHCI", HBA_IDLEN);
                strlcpy(cpi->dev_name, cam_sim_name(sim), DEV_IDLEN);
                cpi->unit_number = cam_sim_unit(sim);
                cpi->transport = XPORT_SATA;
                cpi->transport_version = XPORT_VERSION_UNSPECIFIED;
                cpi->protocol = PROTO_ATA;
                cpi->protocol_version = PROTO_VERSION_UNSPECIFIED;
                cpi->maxio = ctob(AHCI_SG_ENTRIES - 1);
                /* ATI SB600 can't handle 256 sectors with FPDMA (NCQ). */
                if (ch->quirks & AHCI_Q_MAXIO_64K)
                        cpi->maxio = min(cpi->maxio, 128 * 512);
                cpi->hba_vendor = ch->vendorid;
                cpi->hba_device = ch->deviceid;
                cpi->hba_subvendor = ch->subvendorid;
                cpi->hba_subdevice = ch->subdeviceid;
                cpi->ccb_h.status = CAM_REQ_CMP;
                break;
        }
        default:
                ccb->ccb_h.status = CAM_REQ_INVALID;
                break;
        }
        ahci_done(ch, ccb);
}

static void
ahcipoll(struct cam_sim *sim)
{
        struct ahci_channel *ch = (struct ahci_channel *)cam_sim_softc(sim);
        uint32_t istatus;

        /* Read interrupt statuses and process if any. */
        istatus = ATA_INL(ch->r_mem, AHCI_P_IS);
        if (istatus != 0)
                ahci_ch_intr_main(ch, istatus);
        if (ch->resetting != 0 &&
            (--ch->resetpolldiv <= 0 || !callout_pending(&ch->reset_timer))) {
                ch->resetpolldiv = 1000;
                ahci_reset_to(ch);
        }
}

MODULE_VERSION(ahci, 1);
MODULE_DEPEND(ahci, cam, 1, 1, 1);