[SCSI] aic79xx: DV parameter settings

[pandora-kernel.git] / drivers / scsi / aic7xxx / aic79xx_osm.c

/*
 * Adaptec AIC79xx device driver for Linux.
 *
 * $Id: //depot/aic7xxx/linux/drivers/scsi/aic7xxx/aic79xx_osm.c#171 $
 *
 * --------------------------------------------------------------------------
 * Copyright (c) 1994-2000 Justin T. Gibbs.
 * Copyright (c) 1997-1999 Doug Ledford
 * Copyright (c) 2000-2003 Adaptec Inc.
 * 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.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR 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 DAMAGES.
 */

#include "aic79xx_osm.h"
#include "aic79xx_inline.h"
#include <scsi/scsicam.h>

static struct scsi_transport_template *ahd_linux_transport_template = NULL;

/*
 * Include aiclib.c as part of our
 * "module dependencies are hard" work around.
 */
#include "aiclib.c"

#include <linux/init.h>         /* __setup */
#include <linux/mm.h>           /* For fetching system memory size */
#include <linux/blkdev.h>               /* For block_size() */
#include <linux/delay.h>        /* For ssleep/msleep */

/*
 * Lock protecting manipulation of the ahd softc list.
 */
spinlock_t ahd_list_spinlock;

/*
 * Bucket size for counting good commands in between bad ones.
 */
#define AHD_LINUX_ERR_THRESH    1000

/*
 * Set this to the delay in seconds after SCSI bus reset.
 * Note, we honor this only for the initial bus reset.
 * The scsi error recovery code performs its own bus settle
 * delay handling for error recovery actions.
 */
#ifdef CONFIG_AIC79XX_RESET_DELAY_MS
#define AIC79XX_RESET_DELAY CONFIG_AIC79XX_RESET_DELAY_MS
#else
#define AIC79XX_RESET_DELAY 5000
#endif

/*
 * To change the default number of tagged transactions allowed per-device,
 * add a line to the lilo.conf file like:
 * append="aic79xx=verbose,tag_info:{{32,32,32,32},{32,32,32,32}}"
 * which will result in the first four devices on the first two
 * controllers being set to a tagged queue depth of 32.
 *
 * The tag_commands is an array of 16 to allow for wide and twin adapters.
 * Twin adapters will use indexes 0-7 for channel 0, and indexes 8-15
 * for channel 1.
 */
typedef struct {
        uint16_t tag_commands[16];      /* Allow for wide/twin adapters. */
} adapter_tag_info_t;

/*
 * Modify this as you see fit for your system.
 *
 * 0                    tagged queuing disabled
 * 1 <= n <= 253        n == max tags ever dispatched.
 *
 * The driver will throttle the number of commands dispatched to a
 * device if it returns queue full.  For devices with a fixed maximum
 * queue depth, the driver will eventually determine this depth and
 * lock it in (a console message is printed to indicate that a lock
 * has occurred).  On some devices, queue full is returned for a temporary
 * resource shortage.  These devices will return queue full at varying
 * depths.  The driver will throttle back when the queue fulls occur and
 * attempt to slowly increase the depth over time as the device recovers
 * from the resource shortage.
 *
 * In this example, the first line will disable tagged queueing for all
 * the devices on the first probed aic79xx adapter.
 *
 * The second line enables tagged queueing with 4 commands/LUN for IDs
 * (0, 2-11, 13-15), disables tagged queueing for ID 12, and tells the
 * driver to attempt to use up to 64 tags for ID 1.
 *
 * The third line is the same as the first line.
 *
 * The fourth line disables tagged queueing for devices 0 and 3.  It
 * enables tagged queueing for the other IDs, with 16 commands/LUN
 * for IDs 1 and 4, 127 commands/LUN for ID 8, and 4 commands/LUN for
 * IDs 2, 5-7, and 9-15.
 */

/*
 * NOTE: The below structure is for reference only, the actual structure
 *       to modify in order to change things is just below this comment block.
adapter_tag_info_t aic79xx_tag_info[] =
{
        {{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
        {{4, 64, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 0, 4, 4, 4}},
        {{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
        {{0, 16, 4, 0, 16, 4, 4, 4, 127, 4, 4, 4, 4, 4, 4, 4}}
};
*/

#ifdef CONFIG_AIC79XX_CMDS_PER_DEVICE
#define AIC79XX_CMDS_PER_DEVICE CONFIG_AIC79XX_CMDS_PER_DEVICE
#else
#define AIC79XX_CMDS_PER_DEVICE AHD_MAX_QUEUE
#endif

#define AIC79XX_CONFIGED_TAG_COMMANDS {                                 \
        AIC79XX_CMDS_PER_DEVICE, AIC79XX_CMDS_PER_DEVICE,               \
        AIC79XX_CMDS_PER_DEVICE, AIC79XX_CMDS_PER_DEVICE,               \
        AIC79XX_CMDS_PER_DEVICE, AIC79XX_CMDS_PER_DEVICE,               \
        AIC79XX_CMDS_PER_DEVICE, AIC79XX_CMDS_PER_DEVICE,               \
        AIC79XX_CMDS_PER_DEVICE, AIC79XX_CMDS_PER_DEVICE,               \
        AIC79XX_CMDS_PER_DEVICE, AIC79XX_CMDS_PER_DEVICE,               \
        AIC79XX_CMDS_PER_DEVICE, AIC79XX_CMDS_PER_DEVICE,               \
        AIC79XX_CMDS_PER_DEVICE, AIC79XX_CMDS_PER_DEVICE                \
}

/*
 * By default, use the number of commands specified by
 * the users kernel configuration.
 */
static adapter_tag_info_t aic79xx_tag_info[] =
{
        {AIC79XX_CONFIGED_TAG_COMMANDS},
        {AIC79XX_CONFIGED_TAG_COMMANDS},
        {AIC79XX_CONFIGED_TAG_COMMANDS},
        {AIC79XX_CONFIGED_TAG_COMMANDS},
        {AIC79XX_CONFIGED_TAG_COMMANDS},
        {AIC79XX_CONFIGED_TAG_COMMANDS},
        {AIC79XX_CONFIGED_TAG_COMMANDS},
        {AIC79XX_CONFIGED_TAG_COMMANDS},
        {AIC79XX_CONFIGED_TAG_COMMANDS},
        {AIC79XX_CONFIGED_TAG_COMMANDS},
        {AIC79XX_CONFIGED_TAG_COMMANDS},
        {AIC79XX_CONFIGED_TAG_COMMANDS},
        {AIC79XX_CONFIGED_TAG_COMMANDS},
        {AIC79XX_CONFIGED_TAG_COMMANDS},
        {AIC79XX_CONFIGED_TAG_COMMANDS},
        {AIC79XX_CONFIGED_TAG_COMMANDS}
};

/*
 * The I/O cell on the chip is very configurable in respect to its analog
 * characteristics.  Set the defaults here; they can be overriden with
 * the proper insmod parameters.
 */
struct ahd_linux_iocell_opts
{
        uint8_t precomp;
        uint8_t slewrate;
        uint8_t amplitude;
};
#define AIC79XX_DEFAULT_PRECOMP         0xFF
#define AIC79XX_DEFAULT_SLEWRATE        0xFF
#define AIC79XX_DEFAULT_AMPLITUDE       0xFF
#define AIC79XX_DEFAULT_IOOPTS                  \
{                                               \
        AIC79XX_DEFAULT_PRECOMP,                \
        AIC79XX_DEFAULT_SLEWRATE,               \
        AIC79XX_DEFAULT_AMPLITUDE               \
}
#define AIC79XX_PRECOMP_INDEX   0
#define AIC79XX_SLEWRATE_INDEX  1
#define AIC79XX_AMPLITUDE_INDEX 2
static struct ahd_linux_iocell_opts aic79xx_iocell_info[] =
{
        AIC79XX_DEFAULT_IOOPTS,
        AIC79XX_DEFAULT_IOOPTS,
        AIC79XX_DEFAULT_IOOPTS,
        AIC79XX_DEFAULT_IOOPTS,
        AIC79XX_DEFAULT_IOOPTS,
        AIC79XX_DEFAULT_IOOPTS,
        AIC79XX_DEFAULT_IOOPTS,
        AIC79XX_DEFAULT_IOOPTS,
        AIC79XX_DEFAULT_IOOPTS,
        AIC79XX_DEFAULT_IOOPTS,
        AIC79XX_DEFAULT_IOOPTS,
        AIC79XX_DEFAULT_IOOPTS,
        AIC79XX_DEFAULT_IOOPTS,
        AIC79XX_DEFAULT_IOOPTS,
        AIC79XX_DEFAULT_IOOPTS,
        AIC79XX_DEFAULT_IOOPTS
};

/*
 * There should be a specific return value for this in scsi.h, but
 * it seems that most drivers ignore it.
 */
#define DID_UNDERFLOW   DID_ERROR

void
ahd_print_path(struct ahd_softc *ahd, struct scb *scb)
{
        printk("(scsi%d:%c:%d:%d): ",
               ahd->platform_data->host->host_no,
               scb != NULL ? SCB_GET_CHANNEL(ahd, scb) : 'X',
               scb != NULL ? SCB_GET_TARGET(ahd, scb) : -1,
               scb != NULL ? SCB_GET_LUN(scb) : -1);
}

/*
 * XXX - these options apply unilaterally to _all_ adapters
 *       cards in the system.  This should be fixed.  Exceptions to this
 *       rule are noted in the comments.
 */

/*
 * Skip the scsi bus reset.  Non 0 make us skip the reset at startup.  This
 * has no effect on any later resets that might occur due to things like
 * SCSI bus timeouts.
 */
static uint32_t aic79xx_no_reset;

/*
 * Certain PCI motherboards will scan PCI devices from highest to lowest,
 * others scan from lowest to highest, and they tend to do all kinds of
 * strange things when they come into contact with PCI bridge chips.  The
 * net result of all this is that the PCI card that is actually used to boot
 * the machine is very hard to detect.  Most motherboards go from lowest
 * PCI slot number to highest, and the first SCSI controller found is the
 * one you boot from.  The only exceptions to this are when a controller
 * has its BIOS disabled.  So, we by default sort all of our SCSI controllers
 * from lowest PCI slot number to highest PCI slot number.  We also force
 * all controllers with their BIOS disabled to the end of the list.  This
 * works on *almost* all computers.  Where it doesn't work, we have this
 * option.  Setting this option to non-0 will reverse the order of the sort
 * to highest first, then lowest, but will still leave cards with their BIOS
 * disabled at the very end.  That should fix everyone up unless there are
 * really strange cirumstances.
 */
static uint32_t aic79xx_reverse_scan;

/*
 * Should we force EXTENDED translation on a controller.
 *     0 == Use whatever is in the SEEPROM or default to off
 *     1 == Use whatever is in the SEEPROM or default to on
 */
static uint32_t aic79xx_extended;

/*
 * PCI bus parity checking of the Adaptec controllers.  This is somewhat
 * dubious at best.  To my knowledge, this option has never actually
 * solved a PCI parity problem, but on certain machines with broken PCI
 * chipset configurations, it can generate tons of false error messages.
 * It's included in the driver for completeness.
 *   0     = Shut off PCI parity check
 *   non-0 = Enable PCI parity check
 *
 * NOTE: you can't actually pass -1 on the lilo prompt.  So, to set this
 * variable to -1 you would actually want to simply pass the variable
 * name without a number.  That will invert the 0 which will result in
 * -1.
 */
static uint32_t aic79xx_pci_parity = ~0;

/*
 * There are lots of broken chipsets in the world.  Some of them will
 * violate the PCI spec when we issue byte sized memory writes to our
 * controller.  I/O mapped register access, if allowed by the given
 * platform, will work in almost all cases.
 */
uint32_t aic79xx_allow_memio = ~0;

/*
 * aic79xx_detect() has been run, so register all device arrivals
 * immediately with the system rather than deferring to the sorted
 * attachment performed by aic79xx_detect().
 */
int aic79xx_detect_complete;

/*
 * So that we can set how long each device is given as a selection timeout.
 * The table of values goes like this:
 *   0 - 256ms
 *   1 - 128ms
 *   2 - 64ms
 *   3 - 32ms
 * We default to 256ms because some older devices need a longer time
 * to respond to initial selection.
 */
static uint32_t aic79xx_seltime;

/*
 * Certain devices do not perform any aging on commands.  Should the
 * device be saturated by commands in one portion of the disk, it is
 * possible for transactions on far away sectors to never be serviced.
 * To handle these devices, we can periodically send an ordered tag to
 * force all outstanding transactions to be serviced prior to a new
 * transaction.
 */
uint32_t aic79xx_periodic_otag;

/*
 * Module information and settable options.
 */
static char *aic79xx = NULL;

MODULE_AUTHOR("Maintainer: Justin T. Gibbs <gibbs@scsiguy.com>");
MODULE_DESCRIPTION("Adaptec Aic790X U320 SCSI Host Bus Adapter driver");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_VERSION(AIC79XX_DRIVER_VERSION);
module_param(aic79xx, charp, 0444);
MODULE_PARM_DESC(aic79xx,
"period delimited, options string.\n"
"       verbose                 Enable verbose/diagnostic logging\n"
"       allow_memio             Allow device registers to be memory mapped\n"
"       debug                   Bitmask of debug values to enable\n"
"       no_reset                Supress initial bus resets\n"
"       extended                Enable extended geometry on all controllers\n"
"       periodic_otag           Send an ordered tagged transaction\n"
"                               periodically to prevent tag starvation.\n"
"                               This may be required by some older disk\n"
"                               or drives/RAID arrays.\n"
"       reverse_scan            Sort PCI devices highest Bus/Slot to lowest\n"
"       tag_info:<tag_str>      Set per-target tag depth\n"
"       global_tag_depth:<int>  Global tag depth for all targets on all buses\n"
"       slewrate:<slewrate_list>Set the signal slew rate (0-15).\n"
"       precomp:<pcomp_list>    Set the signal precompensation (0-7).\n"
"       amplitude:<int>         Set the signal amplitude (0-7).\n"
"       seltime:<int>           Selection Timeout:\n"
"                               (0/256ms,1/128ms,2/64ms,3/32ms)\n"
"\n"
"       Sample /etc/modprobe.conf line:\n"
"               Enable verbose logging\n"
"               Set tag depth on Controller 2/Target 2 to 10 tags\n"
"               Shorten the selection timeout to 128ms\n"
"\n"
"       options aic79xx 'aic79xx=verbose.tag_info:{{}.{}.{..10}}.seltime:1'\n"
"\n");

static void ahd_linux_handle_scsi_status(struct ahd_softc *,
                                         struct scsi_device *,
                                         struct scb *);
static void ahd_linux_queue_cmd_complete(struct ahd_softc *ahd,
                                         struct scsi_cmnd *cmd);
static void ahd_linux_sem_timeout(u_long arg);
static int  ahd_linux_queue_recovery_cmd(struct scsi_cmnd *cmd, scb_flag flag);
static void ahd_linux_initialize_scsi_bus(struct ahd_softc *ahd);
static u_int ahd_linux_user_tagdepth(struct ahd_softc *ahd,
                                     struct ahd_devinfo *devinfo);
static void ahd_linux_device_queue_depth(struct scsi_device *);
static int ahd_linux_run_command(struct ahd_softc*,
                                 struct ahd_linux_device *,
                                 struct scsi_cmnd *);
static void ahd_linux_setup_tag_info_global(char *p);
static aic_option_callback_t ahd_linux_setup_tag_info;
static aic_option_callback_t ahd_linux_setup_iocell_info;
static int  aic79xx_setup(char *c);
static int  ahd_linux_next_unit(void);

/****************************** Inlines ***************************************/
static __inline void ahd_linux_unmap_scb(struct ahd_softc*, struct scb*);

static __inline void
ahd_linux_unmap_scb(struct ahd_softc *ahd, struct scb *scb)
{
        struct scsi_cmnd *cmd;
        int direction;

        cmd = scb->io_ctx;
        direction = cmd->sc_data_direction;
        ahd_sync_sglist(ahd, scb, BUS_DMASYNC_POSTWRITE);
        if (cmd->use_sg != 0) {
                struct scatterlist *sg;

                sg = (struct scatterlist *)cmd->request_buffer;
                pci_unmap_sg(ahd->dev_softc, sg, cmd->use_sg, direction);
        } else if (cmd->request_bufflen != 0) {
                pci_unmap_single(ahd->dev_softc,
                                 scb->platform_data->buf_busaddr,
                                 cmd->request_bufflen, direction);
        }
}

/******************************** Macros **************************************/
#define BUILD_SCSIID(ahd, cmd)                                          \
        ((((cmd)->device->id << TID_SHIFT) & TID) | (ahd)->our_id)

/*
 * Try to detect an Adaptec 79XX controller.
 */
static int
ahd_linux_detect(struct scsi_host_template *template)
{
        struct  ahd_softc *ahd;
        int     found;
        int     error = 0;

        /*
         * If we've been passed any parameters, process them now.
         */
        if (aic79xx)
                aic79xx_setup(aic79xx);

        template->proc_name = "aic79xx";

        /*
         * Initialize our softc list lock prior to
         * probing for any adapters.
         */
        ahd_list_lockinit();

#ifdef CONFIG_PCI
        error = ahd_linux_pci_init();
        if (error)
                return error;
#endif

        /*
         * Register with the SCSI layer all
         * controllers we've found.
         */
        found = 0;
        TAILQ_FOREACH(ahd, &ahd_tailq, links) {

                if (ahd_linux_register_host(ahd, template) == 0)
                        found++;
        }
        aic79xx_detect_complete++;
        return found;
}

/*
 * Return a string describing the driver.
 */
static const char *
ahd_linux_info(struct Scsi_Host *host)
{
        static char buffer[512];
        char    ahd_info[256];
        char   *bp;
        struct ahd_softc *ahd;

        bp = &buffer[0];
        ahd = *(struct ahd_softc **)host->hostdata;
        memset(bp, 0, sizeof(buffer));
        strcpy(bp, "Adaptec AIC79XX PCI-X SCSI HBA DRIVER, Rev ");
        strcat(bp, AIC79XX_DRIVER_VERSION);
        strcat(bp, "\n");
        strcat(bp, "        <");
        strcat(bp, ahd->description);
        strcat(bp, ">\n");
        strcat(bp, "        ");
        ahd_controller_info(ahd, ahd_info);
        strcat(bp, ahd_info);
        strcat(bp, "\n");

        return (bp);
}

/*
 * Queue an SCB to the controller.
 */
static int
ahd_linux_queue(struct scsi_cmnd * cmd, void (*scsi_done) (struct scsi_cmnd *))
{
        struct   ahd_softc *ahd;
        struct   ahd_linux_device *dev = scsi_transport_device_data(cmd->device);

        ahd = *(struct ahd_softc **)cmd->device->host->hostdata;

        /*
         * Close the race of a command that was in the process of
         * being queued to us just as our simq was frozen.  Let
         * DV commands through so long as we are only frozen to
         * perform DV.
         */
        if (ahd->platform_data->qfrozen != 0) {
                printf("%s: queue frozen\n", ahd_name(ahd));

                return SCSI_MLQUEUE_HOST_BUSY;
        }

        /*
         * Save the callback on completion function.
         */
        cmd->scsi_done = scsi_done;

        cmd->result = CAM_REQ_INPROG << 16;

        return ahd_linux_run_command(ahd, dev, cmd);
}

static inline struct scsi_target **
ahd_linux_target_in_softc(struct scsi_target *starget)
{
        struct  ahd_softc *ahd =
                *((struct ahd_softc **)dev_to_shost(&starget->dev)->hostdata);
        unsigned int target_offset;

        target_offset = starget->id;
        if (starget->channel != 0)
                target_offset += 8;

        return &ahd->platform_data->starget[target_offset];
}

static int
ahd_linux_target_alloc(struct scsi_target *starget)
{
        struct  ahd_softc *ahd =
                *((struct ahd_softc **)dev_to_shost(&starget->dev)->hostdata);
        unsigned long flags;
        struct scsi_target **ahd_targp = ahd_linux_target_in_softc(starget);
        struct ahd_linux_target *targ = scsi_transport_target_data(starget);
        struct ahd_devinfo devinfo;
        struct ahd_initiator_tinfo *tinfo;
        struct ahd_tmode_tstate *tstate;
        char channel = starget->channel + 'A';

        ahd_lock(ahd, &flags);

        BUG_ON(*ahd_targp != NULL);

        *ahd_targp = starget;
        memset(targ, 0, sizeof(*targ));

        tinfo = ahd_fetch_transinfo(ahd, channel, ahd->our_id,
                                    starget->id, &tstate);
        ahd_compile_devinfo(&devinfo, ahd->our_id, starget->id,
                            CAM_LUN_WILDCARD, channel,
                            ROLE_INITIATOR);
        spi_min_period(starget) = AHD_SYNCRATE_MAX; /* We can do U320 */
        if ((ahd->bugs & AHD_PACED_NEGTABLE_BUG) != 0)
                spi_max_offset(starget) = MAX_OFFSET_PACED_BUG;
        else
                spi_max_offset(starget) = MAX_OFFSET_PACED;
        spi_max_width(starget) = ahd->features & AHD_WIDE;

        ahd_set_syncrate(ahd, &devinfo, 0, 0, 0,
                         AHD_TRANS_GOAL, /*paused*/FALSE);
        ahd_set_width(ahd, &devinfo, MSG_EXT_WDTR_BUS_8_BIT,
                      AHD_TRANS_GOAL, /*paused*/FALSE);
        ahd_unlock(ahd, &flags);

        return 0;
}

static void
ahd_linux_target_destroy(struct scsi_target *starget)
{
        struct scsi_target **ahd_targp = ahd_linux_target_in_softc(starget);

        *ahd_targp = NULL;
}

static int
ahd_linux_slave_alloc(struct scsi_device *sdev)
{
        struct  ahd_softc *ahd =
                *((struct ahd_softc **)sdev->host->hostdata);
        struct scsi_target *starget = sdev->sdev_target;
        struct ahd_linux_target *targ = scsi_transport_target_data(starget);
        struct ahd_linux_device *dev;

        if (bootverbose)
                printf("%s: Slave Alloc %d\n", ahd_name(ahd), sdev->id);

        BUG_ON(targ->sdev[sdev->lun] != NULL);

        dev = scsi_transport_device_data(sdev);
        memset(dev, 0, sizeof(*dev));

        /*
         * We start out life using untagged
         * transactions of which we allow one.
         */
        dev->openings = 1;

        /*
         * Set maxtags to 0.  This will be changed if we
         * later determine that we are dealing with
         * a tagged queuing capable device.
         */
        dev->maxtags = 0;
        
        targ->sdev[sdev->lun] = sdev;

        return (0);
}

static int
ahd_linux_slave_configure(struct scsi_device *sdev)
{
        struct  ahd_softc *ahd;

        ahd = *((struct ahd_softc **)sdev->host->hostdata);
        if (bootverbose)
                printf("%s: Slave Configure %d\n", ahd_name(ahd), sdev->id);

        ahd_linux_device_queue_depth(sdev);

        /* Initial Domain Validation */
        if (!spi_initial_dv(sdev->sdev_target))
                spi_dv_device(sdev);

        return 0;
}

static void
ahd_linux_slave_destroy(struct scsi_device *sdev)
{
        struct  ahd_softc *ahd;
        struct  ahd_linux_device *dev = scsi_transport_device_data(sdev);
        struct  ahd_linux_target *targ = scsi_transport_target_data(sdev->sdev_target);

        ahd = *((struct ahd_softc **)sdev->host->hostdata);
        if (bootverbose)
                printf("%s: Slave Destroy %d\n", ahd_name(ahd), sdev->id);

        BUG_ON(dev->active);

        targ->sdev[sdev->lun] = NULL;

}

#if defined(__i386__)
/*
 * Return the disk geometry for the given SCSI device.
 */
static int
ahd_linux_biosparam(struct scsi_device *sdev, struct block_device *bdev,
                    sector_t capacity, int geom[])
{
        uint8_t *bh;
        int      heads;
        int      sectors;
        int      cylinders;
        int      ret;
        int      extended;
        struct   ahd_softc *ahd;

        ahd = *((struct ahd_softc **)sdev->host->hostdata);

        bh = scsi_bios_ptable(bdev);
        if (bh) {
                ret = scsi_partsize(bh, capacity,
                                    &geom[2], &geom[0], &geom[1]);
                kfree(bh);
                if (ret != -1)
                        return (ret);
        }
        heads = 64;
        sectors = 32;
        cylinders = aic_sector_div(capacity, heads, sectors);

        if (aic79xx_extended != 0)
                extended = 1;
        else
                extended = (ahd->flags & AHD_EXTENDED_TRANS_A) != 0;
        if (extended && cylinders >= 1024) {
                heads = 255;
                sectors = 63;
                cylinders = aic_sector_div(capacity, heads, sectors);
        }
        geom[0] = heads;
        geom[1] = sectors;
        geom[2] = cylinders;
        return (0);
}
#endif

/*
 * Abort the current SCSI command(s).
 */
static int
ahd_linux_abort(struct scsi_cmnd *cmd)
{
        int error;

        error = ahd_linux_queue_recovery_cmd(cmd, SCB_ABORT);
        if (error != 0)
                printf("aic79xx_abort returns 0x%x\n", error);
        return error;
}

/*
 * Attempt to send a target reset message to the device that timed out.
 */
static int
ahd_linux_dev_reset(struct scsi_cmnd *cmd)
{
        int error;

        error = ahd_linux_queue_recovery_cmd(cmd, SCB_DEVICE_RESET);
        if (error != 0)
                printf("aic79xx_dev_reset returns 0x%x\n", error);
        return error;
}

/*
 * Reset the SCSI bus.
 */
static int
ahd_linux_bus_reset(struct scsi_cmnd *cmd)
{
        struct ahd_softc *ahd;
        u_long s;
        int    found;

        ahd = *(struct ahd_softc **)cmd->device->host->hostdata;
#ifdef AHD_DEBUG
        if ((ahd_debug & AHD_SHOW_RECOVERY) != 0)
                printf("%s: Bus reset called for cmd %p\n",
                       ahd_name(ahd), cmd);
#endif
        ahd_lock(ahd, &s);
        found = ahd_reset_channel(ahd, cmd->device->channel + 'A',
                                  /*initiate reset*/TRUE);
        ahd_unlock(ahd, &s);

        if (bootverbose)
                printf("%s: SCSI bus reset delivered. "
                       "%d SCBs aborted.\n", ahd_name(ahd), found);

        return (SUCCESS);
}

struct scsi_host_template aic79xx_driver_template = {
        .module                 = THIS_MODULE,
        .name                   = "aic79xx",
        .proc_info              = ahd_linux_proc_info,
        .info                   = ahd_linux_info,
        .queuecommand           = ahd_linux_queue,
        .eh_abort_handler       = ahd_linux_abort,
        .eh_device_reset_handler = ahd_linux_dev_reset,
        .eh_bus_reset_handler   = ahd_linux_bus_reset,
#if defined(__i386__)
        .bios_param             = ahd_linux_biosparam,
#endif
        .can_queue              = AHD_MAX_QUEUE,
        .this_id                = -1,
        .cmd_per_lun            = 2,
        .use_clustering         = ENABLE_CLUSTERING,
        .slave_alloc            = ahd_linux_slave_alloc,
        .slave_configure        = ahd_linux_slave_configure,
        .slave_destroy          = ahd_linux_slave_destroy,
        .target_alloc           = ahd_linux_target_alloc,
        .target_destroy         = ahd_linux_target_destroy,
};

/******************************** Bus DMA *************************************/
int
ahd_dma_tag_create(struct ahd_softc *ahd, bus_dma_tag_t parent,
                   bus_size_t alignment, bus_size_t boundary,
                   dma_addr_t lowaddr, dma_addr_t highaddr,
                   bus_dma_filter_t *filter, void *filterarg,
                   bus_size_t maxsize, int nsegments,
                   bus_size_t maxsegsz, int flags, bus_dma_tag_t *ret_tag)
{
        bus_dma_tag_t dmat;

        dmat = malloc(sizeof(*dmat), M_DEVBUF, M_NOWAIT);
        if (dmat == NULL)
                return (ENOMEM);

        /*
         * Linux is very simplistic about DMA memory.  For now don't
         * maintain all specification information.  Once Linux supplies
         * better facilities for doing these operations, or the
         * needs of this particular driver change, we might need to do
         * more here.
         */
        dmat->alignment = alignment;
        dmat->boundary = boundary;
        dmat->maxsize = maxsize;
        *ret_tag = dmat;
        return (0);
}

void
ahd_dma_tag_destroy(struct ahd_softc *ahd, bus_dma_tag_t dmat)
{
        free(dmat, M_DEVBUF);
}

int
ahd_dmamem_alloc(struct ahd_softc *ahd, bus_dma_tag_t dmat, void** vaddr,
                 int flags, bus_dmamap_t *mapp)
{
        *vaddr = pci_alloc_consistent(ahd->dev_softc,
                                      dmat->maxsize, mapp);
        if (*vaddr == NULL)
                return (ENOMEM);
        return(0);
}

void
ahd_dmamem_free(struct ahd_softc *ahd, bus_dma_tag_t dmat,
                void* vaddr, bus_dmamap_t map)
{
        pci_free_consistent(ahd->dev_softc, dmat->maxsize,
                            vaddr, map);
}

int
ahd_dmamap_load(struct ahd_softc *ahd, bus_dma_tag_t dmat, bus_dmamap_t map,
                void *buf, bus_size_t buflen, bus_dmamap_callback_t *cb,
                void *cb_arg, int flags)
{
        /*
         * Assume for now that this will only be used during
         * initialization and not for per-transaction buffer mapping.
         */
        bus_dma_segment_t stack_sg;

        stack_sg.ds_addr = map;
        stack_sg.ds_len = dmat->maxsize;
        cb(cb_arg, &stack_sg, /*nseg*/1, /*error*/0);
        return (0);
}

void
ahd_dmamap_destroy(struct ahd_softc *ahd, bus_dma_tag_t dmat, bus_dmamap_t map)
{
}

int
ahd_dmamap_unload(struct ahd_softc *ahd, bus_dma_tag_t dmat, bus_dmamap_t map)
{
        /* Nothing to do */
        return (0);
}

/********************* Platform Dependent Functions ***************************/
/*
 * Compare "left hand" softc with "right hand" softc, returning:
 * < 0 - lahd has a lower priority than rahd
 *   0 - Softcs are equal
 * > 0 - lahd has a higher priority than rahd
 */
int
ahd_softc_comp(struct ahd_softc *lahd, struct ahd_softc *rahd)
{
        int     value;

        /*
         * Under Linux, cards are ordered as follows:
         *      1) PCI devices that are marked as the boot controller.
         *      2) PCI devices with BIOS enabled sorted by bus/slot/func.
         *      3) All remaining PCI devices sorted by bus/slot/func.
         */
#if 0
        value = (lahd->flags & AHD_BOOT_CHANNEL)
              - (rahd->flags & AHD_BOOT_CHANNEL);
        if (value != 0)
                /* Controllers set for boot have a *higher* priority */
                return (value);
#endif

        value = (lahd->flags & AHD_BIOS_ENABLED)
              - (rahd->flags & AHD_BIOS_ENABLED);
        if (value != 0)
                /* Controllers with BIOS enabled have a *higher* priority */
                return (value);

        /* Still equal.  Sort by bus/slot/func. */
        if (aic79xx_reverse_scan != 0)
                value = ahd_get_pci_bus(lahd->dev_softc)
                      - ahd_get_pci_bus(rahd->dev_softc);
        else
                value = ahd_get_pci_bus(rahd->dev_softc)
                      - ahd_get_pci_bus(lahd->dev_softc);
        if (value != 0)
                return (value);
        if (aic79xx_reverse_scan != 0)
                value = ahd_get_pci_slot(lahd->dev_softc)
                      - ahd_get_pci_slot(rahd->dev_softc);
        else
                value = ahd_get_pci_slot(rahd->dev_softc)
                      - ahd_get_pci_slot(lahd->dev_softc);
        if (value != 0)
                return (value);

        value = rahd->channel - lahd->channel;
        return (value);
}

static void
ahd_linux_setup_iocell_info(u_long index, int instance, int targ, int32_t value)
{

        if ((instance >= 0)
         && (instance < NUM_ELEMENTS(aic79xx_iocell_info))) {
                uint8_t *iocell_info;

                iocell_info = (uint8_t*)&aic79xx_iocell_info[instance];
                iocell_info[index] = value & 0xFFFF;
                if (bootverbose)
                        printf("iocell[%d:%ld] = %d\n", instance, index, value);
        }
}

static void
ahd_linux_setup_tag_info_global(char *p)
{
        int tags, i, j;

        tags = simple_strtoul(p + 1, NULL, 0) & 0xff;
        printf("Setting Global Tags= %d\n", tags);

        for (i = 0; i < NUM_ELEMENTS(aic79xx_tag_info); i++) {
                for (j = 0; j < AHD_NUM_TARGETS; j++) {
                        aic79xx_tag_info[i].tag_commands[j] = tags;
                }
        }
}

static void
ahd_linux_setup_tag_info(u_long arg, int instance, int targ, int32_t value)
{

        if ((instance >= 0) && (targ >= 0)
         && (instance < NUM_ELEMENTS(aic79xx_tag_info))
         && (targ < AHD_NUM_TARGETS)) {
                aic79xx_tag_info[instance].tag_commands[targ] = value & 0x1FF;
                if (bootverbose)
                        printf("tag_info[%d:%d] = %d\n", instance, targ, value);
        }
}

/*
 * Handle Linux boot parameters. This routine allows for assigning a value
 * to a parameter with a ':' between the parameter and the value.
 * ie. aic79xx=stpwlev:1,extended
 */
static int
aic79xx_setup(char *s)
{
        int     i, n;
        char   *p;
        char   *end;

        static struct {
                const char *name;
                uint32_t *flag;
        } options[] = {
                { "extended", &aic79xx_extended },
                { "no_reset", &aic79xx_no_reset },
                { "verbose", &aic79xx_verbose },
                { "allow_memio", &aic79xx_allow_memio},
#ifdef AHD_DEBUG
                { "debug", &ahd_debug },
#endif
                { "reverse_scan", &aic79xx_reverse_scan },
                { "periodic_otag", &aic79xx_periodic_otag },
                { "pci_parity", &aic79xx_pci_parity },
                { "seltime", &aic79xx_seltime },
                { "tag_info", NULL },
                { "global_tag_depth", NULL},
                { "slewrate", NULL },
                { "precomp", NULL },
                { "amplitude", NULL },
        };

        end = strchr(s, '\0');

        /*
         * XXX ia64 gcc isn't smart enough to know that NUM_ELEMENTS
         * will never be 0 in this case.
         */      
        n = 0;  

        while ((p = strsep(&s, ",.")) != NULL) {
                if (*p == '\0')
                        continue;
                for (i = 0; i < NUM_ELEMENTS(options); i++) {

                        n = strlen(options[i].name);
                        if (strncmp(options[i].name, p, n) == 0)
                                break;
                }
                if (i == NUM_ELEMENTS(options))
                        continue;

                if (strncmp(p, "global_tag_depth", n) == 0) {
                        ahd_linux_setup_tag_info_global(p + n);
                } else if (strncmp(p, "tag_info", n) == 0) {
                        s = aic_parse_brace_option("tag_info", p + n, end,
                            2, ahd_linux_setup_tag_info, 0);
                } else if (strncmp(p, "slewrate", n) == 0) {
                        s = aic_parse_brace_option("slewrate",
                            p + n, end, 1, ahd_linux_setup_iocell_info,
                            AIC79XX_SLEWRATE_INDEX);
                } else if (strncmp(p, "precomp", n) == 0) {
                        s = aic_parse_brace_option("precomp",
                            p + n, end, 1, ahd_linux_setup_iocell_info,
                            AIC79XX_PRECOMP_INDEX);
                } else if (strncmp(p, "amplitude", n) == 0) {
                        s = aic_parse_brace_option("amplitude",
                            p + n, end, 1, ahd_linux_setup_iocell_info,
                            AIC79XX_AMPLITUDE_INDEX);
                } else if (p[n] == ':') {
                        *(options[i].flag) = simple_strtoul(p + n + 1, NULL, 0);
                } else if (!strncmp(p, "verbose", n)) {
                        *(options[i].flag) = 1;
                } else {
                        *(options[i].flag) ^= 0xFFFFFFFF;
                }
        }
        return 1;
}

__setup("aic79xx=", aic79xx_setup);

uint32_t aic79xx_verbose;

int
ahd_linux_register_host(struct ahd_softc *ahd, struct scsi_host_template *template)
{
        char    buf[80];
        struct  Scsi_Host *host;
        char    *new_name;
        u_long  s;

        template->name = ahd->description;
        host = scsi_host_alloc(template, sizeof(struct ahd_softc *));
        if (host == NULL)
                return (ENOMEM);

        *((struct ahd_softc **)host->hostdata) = ahd;
        ahd_lock(ahd, &s);
        scsi_assign_lock(host, &ahd->platform_data->spin_lock);
        ahd->platform_data->host = host;
        host->can_queue = AHD_MAX_QUEUE;
        host->cmd_per_lun = 2;
        host->sg_tablesize = AHD_NSEG;
        host->this_id = ahd->our_id;
        host->irq = ahd->platform_data->irq;
        host->max_id = (ahd->features & AHD_WIDE) ? 16 : 8;
        host->max_lun = AHD_NUM_LUNS;
        host->max_channel = 0;
        host->sg_tablesize = AHD_NSEG;
        ahd_set_unit(ahd, ahd_linux_next_unit());
        sprintf(buf, "scsi%d", host->host_no);
        new_name = malloc(strlen(buf) + 1, M_DEVBUF, M_NOWAIT);
        if (new_name != NULL) {
                strcpy(new_name, buf);
                ahd_set_name(ahd, new_name);
        }
        host->unique_id = ahd->unit;
        ahd_linux_initialize_scsi_bus(ahd);
        ahd_intr_enable(ahd, TRUE);
        ahd_unlock(ahd, &s);

        host->transportt = ahd_linux_transport_template;

        scsi_add_host(host, &ahd->dev_softc->dev); /* XXX handle failure */
        scsi_scan_host(host);
        return (0);
}

uint64_t
ahd_linux_get_memsize(void)
{
        struct sysinfo si;

        si_meminfo(&si);
        return ((uint64_t)si.totalram << PAGE_SHIFT);
}

/*
 * Find the smallest available unit number to use
 * for a new device.  We don't just use a static
 * count to handle the "repeated hot-(un)plug"
 * scenario.
 */
static int
ahd_linux_next_unit(void)
{
        struct ahd_softc *ahd;
        int unit;

        unit = 0;
retry:
        TAILQ_FOREACH(ahd, &ahd_tailq, links) {
                if (ahd->unit == unit) {
                        unit++;
                        goto retry;
                }
        }
        return (unit);
}

/*
 * Place the SCSI bus into a known state by either resetting it,
 * or forcing transfer negotiations on the next command to any
 * target.
 */
static void
ahd_linux_initialize_scsi_bus(struct ahd_softc *ahd)
{
        u_int target_id;
        u_int numtarg;

        target_id = 0;
        numtarg = 0;

        if (aic79xx_no_reset != 0)
                ahd->flags &= ~AHD_RESET_BUS_A;

        if ((ahd->flags & AHD_RESET_BUS_A) != 0)
                ahd_reset_channel(ahd, 'A', /*initiate_reset*/TRUE);
        else
                numtarg = (ahd->features & AHD_WIDE) ? 16 : 8;

        /*
         * Force negotiation to async for all targets that
         * will not see an initial bus reset.
         */
        for (; target_id < numtarg; target_id++) {
                struct ahd_devinfo devinfo;
                struct ahd_initiator_tinfo *tinfo;
                struct ahd_tmode_tstate *tstate;

                tinfo = ahd_fetch_transinfo(ahd, 'A', ahd->our_id,
                                            target_id, &tstate);
                ahd_compile_devinfo(&devinfo, ahd->our_id, target_id,
                                    CAM_LUN_WILDCARD, 'A', ROLE_INITIATOR);
                ahd_update_neg_request(ahd, &devinfo, tstate,
                                       tinfo, AHD_NEG_ALWAYS);
        }
        /* Give the bus some time to recover */
        if ((ahd->flags & AHD_RESET_BUS_A) != 0) {
                ahd_freeze_simq(ahd);
                init_timer(&ahd->platform_data->reset_timer);
                ahd->platform_data->reset_timer.data = (u_long)ahd;
                ahd->platform_data->reset_timer.expires =
                    jiffies + (AIC79XX_RESET_DELAY * HZ)/1000;
                ahd->platform_data->reset_timer.function =
                    (ahd_linux_callback_t *)ahd_release_simq;
                add_timer(&ahd->platform_data->reset_timer);
        }
}

int
ahd_platform_alloc(struct ahd_softc *ahd, void *platform_arg)
{
        ahd->platform_data =
            malloc(sizeof(struct ahd_platform_data), M_DEVBUF, M_NOWAIT);
        if (ahd->platform_data == NULL)
                return (ENOMEM);
        memset(ahd->platform_data, 0, sizeof(struct ahd_platform_data));
        ahd->platform_data->irq = AHD_LINUX_NOIRQ;
        ahd_lockinit(ahd);
        init_MUTEX_LOCKED(&ahd->platform_data->eh_sem);
        ahd->seltime = (aic79xx_seltime & 0x3) << 4;
        return (0);
}

void
ahd_platform_free(struct ahd_softc *ahd)
{
        struct scsi_target *starget;
        int i, j;

        if (ahd->platform_data != NULL) {
                if (ahd->platform_data->host != NULL) {
                        scsi_remove_host(ahd->platform_data->host);
                        scsi_host_put(ahd->platform_data->host);
                }

                /* destroy all of the device and target objects */
                for (i = 0; i < AHD_NUM_TARGETS; i++) {
                        starget = ahd->platform_data->starget[i];
                        if (starget != NULL) {
                                for (j = 0; j < AHD_NUM_LUNS; j++) {
                                        struct ahd_linux_target *targ =
                                                scsi_transport_target_data(starget);
                                        if (targ->sdev[j] == NULL)
                                                continue;
                                        targ->sdev[j] = NULL;
                                }
                                ahd->platform_data->starget[i] = NULL;
                        }
                }

                if (ahd->platform_data->irq != AHD_LINUX_NOIRQ)
                        free_irq(ahd->platform_data->irq, ahd);
                if (ahd->tags[0] == BUS_SPACE_PIO
                 && ahd->bshs[0].ioport != 0)
                        release_region(ahd->bshs[0].ioport, 256);
                if (ahd->tags[1] == BUS_SPACE_PIO
                 && ahd->bshs[1].ioport != 0)
                        release_region(ahd->bshs[1].ioport, 256);
                if (ahd->tags[0] == BUS_SPACE_MEMIO
                 && ahd->bshs[0].maddr != NULL) {
                        iounmap(ahd->bshs[0].maddr);
                        release_mem_region(ahd->platform_data->mem_busaddr,
                                           0x1000);
                }
                free(ahd->platform_data, M_DEVBUF);
        }
}

void
ahd_platform_init(struct ahd_softc *ahd)
{
        /*
         * Lookup and commit any modified IO Cell options.
         */
        if (ahd->unit < NUM_ELEMENTS(aic79xx_iocell_info)) {
                struct ahd_linux_iocell_opts *iocell_opts;

                iocell_opts = &aic79xx_iocell_info[ahd->unit];
                if (iocell_opts->precomp != AIC79XX_DEFAULT_PRECOMP)
                        AHD_SET_PRECOMP(ahd, iocell_opts->precomp);
                if (iocell_opts->slewrate != AIC79XX_DEFAULT_SLEWRATE)
                        AHD_SET_SLEWRATE(ahd, iocell_opts->slewrate);
                if (iocell_opts->amplitude != AIC79XX_DEFAULT_AMPLITUDE)
                        AHD_SET_AMPLITUDE(ahd, iocell_opts->amplitude);
        }

}

void
ahd_platform_freeze_devq(struct ahd_softc *ahd, struct scb *scb)
{
        ahd_platform_abort_scbs(ahd, SCB_GET_TARGET(ahd, scb),
                                SCB_GET_CHANNEL(ahd, scb),
                                SCB_GET_LUN(scb), SCB_LIST_NULL,
                                ROLE_UNKNOWN, CAM_REQUEUE_REQ);
}

void
ahd_platform_set_tags(struct ahd_softc *ahd, struct ahd_devinfo *devinfo,
                      ahd_queue_alg alg)
{
        struct scsi_target *starget;
        struct ahd_linux_target *targ;
        struct ahd_linux_device *dev;
        struct scsi_device *sdev;
        int was_queuing;
        int now_queuing;

        starget = ahd->platform_data->starget[devinfo->target];
        targ = scsi_transport_target_data(starget);
        BUG_ON(targ == NULL);
        sdev = targ->sdev[devinfo->lun];
        if (sdev == NULL)
                return;

        dev = scsi_transport_device_data(sdev);

        if (dev == NULL)
                return;
        was_queuing = dev->flags & (AHD_DEV_Q_BASIC|AHD_DEV_Q_TAGGED);
        switch (alg) {
        default:
        case AHD_QUEUE_NONE:
                now_queuing = 0;
                break; 
        case AHD_QUEUE_BASIC:
                now_queuing = AHD_DEV_Q_BASIC;
                break;
        case AHD_QUEUE_TAGGED:
                now_queuing = AHD_DEV_Q_TAGGED;
                break;
        }
        if ((dev->flags & AHD_DEV_FREEZE_TIL_EMPTY) == 0
         && (was_queuing != now_queuing)
         && (dev->active != 0)) {
                dev->flags |= AHD_DEV_FREEZE_TIL_EMPTY;
                dev->qfrozen++;
        }

        dev->flags &= ~(AHD_DEV_Q_BASIC|AHD_DEV_Q_TAGGED|AHD_DEV_PERIODIC_OTAG);
        if (now_queuing) {
                u_int usertags;

                usertags = ahd_linux_user_tagdepth(ahd, devinfo);
                if (!was_queuing) {
                        /*
                         * Start out agressively and allow our
                         * dynamic queue depth algorithm to take
                         * care of the rest.
                         */
                        dev->maxtags = usertags;
                        dev->openings = dev->maxtags - dev->active;
                }
                if (dev->maxtags == 0) {
                        /*
                         * Queueing is disabled by the user.
                         */
                        dev->openings = 1;
                } else if (alg == AHD_QUEUE_TAGGED) {
                        dev->flags |= AHD_DEV_Q_TAGGED;
                        if (aic79xx_periodic_otag != 0)
                                dev->flags |= AHD_DEV_PERIODIC_OTAG;
                } else
                        dev->flags |= AHD_DEV_Q_BASIC;
        } else {
                /* We can only have one opening. */
                dev->maxtags = 0;
                dev->openings =  1 - dev->active;
        }

        switch ((dev->flags & (AHD_DEV_Q_BASIC|AHD_DEV_Q_TAGGED))) {
        case AHD_DEV_Q_BASIC:
                scsi_adjust_queue_depth(sdev,
                                        MSG_SIMPLE_TASK,
                                        dev->openings + dev->active);
                break;
        case AHD_DEV_Q_TAGGED:
                scsi_adjust_queue_depth(sdev,
                                        MSG_ORDERED_TASK,
                                        dev->openings + dev->active);
                break;
        default:
                /*
                 * We allow the OS to queue 2 untagged transactions to
                 * us at any time even though we can only execute them
                 * serially on the controller/device.  This should
                 * remove some latency.
                 */
                scsi_adjust_queue_depth(sdev,
                                        /*NON-TAGGED*/0,
                                        /*queue depth*/2);
                break;
        }
}

int
ahd_platform_abort_scbs(struct ahd_softc *ahd, int target, char channel,
                        int lun, u_int tag, role_t role, uint32_t status)
{
        return 0;
}

static u_int
ahd_linux_user_tagdepth(struct ahd_softc *ahd, struct ahd_devinfo *devinfo)
{
        static int warned_user;
        u_int tags;

        tags = 0;
        if ((ahd->user_discenable & devinfo->target_mask) != 0) {
                if (ahd->unit >= NUM_ELEMENTS(aic79xx_tag_info)) {

                        if (warned_user == 0) {
                                printf(KERN_WARNING
"aic79xx: WARNING: Insufficient tag_info instances\n"
"aic79xx: for installed controllers.  Using defaults\n"
"aic79xx: Please update the aic79xx_tag_info array in\n"
"aic79xx: the aic79xx_osm.c source file.\n");
                                warned_user++;
                        }
                        tags = AHD_MAX_QUEUE;
                } else {
                        adapter_tag_info_t *tag_info;

                        tag_info = &aic79xx_tag_info[ahd->unit];
                        tags = tag_info->tag_commands[devinfo->target_offset];
                        if (tags > AHD_MAX_QUEUE)
                                tags = AHD_MAX_QUEUE;
                }
        }
        return (tags);
}

/*
 * Determines the queue depth for a given device.
 */
static void
ahd_linux_device_queue_depth(struct scsi_device *sdev)
{
        struct  ahd_devinfo devinfo;
        u_int   tags;
        struct ahd_softc *ahd = *((struct ahd_softc **)sdev->host->hostdata);

        ahd_compile_devinfo(&devinfo,
                            ahd->our_id,
                            sdev->sdev_target->id, sdev->lun,
                            sdev->sdev_target->channel == 0 ? 'A' : 'B',
                            ROLE_INITIATOR);
        tags = ahd_linux_user_tagdepth(ahd, &devinfo);
        if (tags != 0 && sdev->tagged_supported != 0) {

                ahd_set_tags(ahd, &devinfo, AHD_QUEUE_TAGGED);
                ahd_print_devinfo(ahd, &devinfo);
                printf("Tagged Queuing enabled.  Depth %d\n", tags);
        } else {
                ahd_set_tags(ahd, &devinfo, AHD_QUEUE_NONE);
        }
}

static int
ahd_linux_run_command(struct ahd_softc *ahd, struct ahd_linux_device *dev,
                      struct scsi_cmnd *cmd)
{
        struct   scb *scb;
        struct   hardware_scb *hscb;
        struct   ahd_initiator_tinfo *tinfo;
        struct   ahd_tmode_tstate *tstate;
        u_int    col_idx;
        uint16_t mask;

        /*
         * Get an scb to use.
         */
        tinfo = ahd_fetch_transinfo(ahd, 'A', ahd->our_id,
                                    cmd->device->id, &tstate);
        if ((dev->flags & (AHD_DEV_Q_TAGGED|AHD_DEV_Q_BASIC)) == 0
         || (tinfo->curr.ppr_options & MSG_EXT_PPR_IU_REQ) != 0) {
                col_idx = AHD_NEVER_COL_IDX;
        } else {
                col_idx = AHD_BUILD_COL_IDX(cmd->device->id,
                                            cmd->device->lun);
        }
        if ((scb = ahd_get_scb(ahd, col_idx)) == NULL) {
                ahd->flags |= AHD_RESOURCE_SHORTAGE;
                return SCSI_MLQUEUE_HOST_BUSY;
        }

        scb->io_ctx = cmd;
        scb->platform_data->dev = dev;
        hscb = scb->hscb;
        cmd->host_scribble = (char *)scb;

        /*
         * Fill out basics of the HSCB.
         */
        hscb->control = 0;
        hscb->scsiid = BUILD_SCSIID(ahd, cmd);
        hscb->lun = cmd->device->lun;
        scb->hscb->task_management = 0;
        mask = SCB_GET_TARGET_MASK(ahd, scb);

        if ((ahd->user_discenable & mask) != 0)
                hscb->control |= DISCENB;

        if ((tinfo->curr.ppr_options & MSG_EXT_PPR_IU_REQ) != 0)
                scb->flags |= SCB_PACKETIZED;

        if ((tstate->auto_negotiate & mask) != 0) {
                scb->flags |= SCB_AUTO_NEGOTIATE;
                scb->hscb->control |= MK_MESSAGE;
        }

        if ((dev->flags & (AHD_DEV_Q_TAGGED|AHD_DEV_Q_BASIC)) != 0) {
                int     msg_bytes;
                uint8_t tag_msgs[2];

                msg_bytes = scsi_populate_tag_msg(cmd, tag_msgs);
                if (msg_bytes && tag_msgs[0] != MSG_SIMPLE_TASK) {
                        hscb->control |= tag_msgs[0];
                        if (tag_msgs[0] == MSG_ORDERED_TASK)
                                dev->commands_since_idle_or_otag = 0;
                } else
                if (dev->commands_since_idle_or_otag == AHD_OTAG_THRESH
                 && (dev->flags & AHD_DEV_Q_TAGGED) != 0) {
                        hscb->control |= MSG_ORDERED_TASK;
                        dev->commands_since_idle_or_otag = 0;
                } else {
                        hscb->control |= MSG_SIMPLE_TASK;
                }
        }

        hscb->cdb_len = cmd->cmd_len;
        memcpy(hscb->shared_data.idata.cdb, cmd->cmnd, hscb->cdb_len);

        scb->platform_data->xfer_len = 0;
        ahd_set_residual(scb, 0);
        ahd_set_sense_residual(scb, 0);
        scb->sg_count = 0;
        if (cmd->use_sg != 0) {
                void    *sg;
                struct   scatterlist *cur_seg;
                u_int    nseg;
                int      dir;

                cur_seg = (struct scatterlist *)cmd->request_buffer;
                dir = cmd->sc_data_direction;
                nseg = pci_map_sg(ahd->dev_softc, cur_seg,
                                  cmd->use_sg, dir);
                scb->platform_data->xfer_len = 0;
                for (sg = scb->sg_list; nseg > 0; nseg--, cur_seg++) {
                        dma_addr_t addr;
                        bus_size_t len;

                        addr = sg_dma_address(cur_seg);
                        len = sg_dma_len(cur_seg);
                        scb->platform_data->xfer_len += len;
                        sg = ahd_sg_setup(ahd, scb, sg, addr, len,
                                          /*last*/nseg == 1);
                }
        } else if (cmd->request_bufflen != 0) {
                void *sg;
                dma_addr_t addr;
                int dir;

                sg = scb->sg_list;
                dir = cmd->sc_data_direction;
                addr = pci_map_single(ahd->dev_softc,
                                      cmd->request_buffer,
                                      cmd->request_bufflen, dir);
                scb->platform_data->xfer_len = cmd->request_bufflen;
                scb->platform_data->buf_busaddr = addr;
                sg = ahd_sg_setup(ahd, scb, sg, addr,
                                  cmd->request_bufflen, /*last*/TRUE);
        }

        LIST_INSERT_HEAD(&ahd->pending_scbs, scb, pending_links);
        dev->openings--;
        dev->active++;
        dev->commands_issued++;

        if ((dev->flags & AHD_DEV_PERIODIC_OTAG) != 0)
                dev->commands_since_idle_or_otag++;
        scb->flags |= SCB_ACTIVE;
        ahd_queue_scb(ahd, scb);

        return 0;
}

/*
 * SCSI controller interrupt handler.
 */
irqreturn_t
ahd_linux_isr(int irq, void *dev_id, struct pt_regs * regs)
{
        struct  ahd_softc *ahd;
        u_long  flags;
        int     ours;

        ahd = (struct ahd_softc *) dev_id;
        ahd_lock(ahd, &flags); 
        ours = ahd_intr(ahd);
        ahd_unlock(ahd, &flags);
        return IRQ_RETVAL(ours);
}

void
ahd_platform_flushwork(struct ahd_softc *ahd)
{

}

void
ahd_send_async(struct ahd_softc *ahd, char channel,
               u_int target, u_int lun, ac_code code, void *arg)
{
        switch (code) {
        case AC_TRANSFER_NEG:
        {
                char    buf[80];
                struct  scsi_target *starget;
                struct  ahd_linux_target *targ;
                struct  info_str info;
                struct  ahd_initiator_tinfo *tinfo;
                struct  ahd_tmode_tstate *tstate;
                unsigned int target_ppr_options;

                BUG_ON(target == CAM_TARGET_WILDCARD);

                info.buffer = buf;
                info.length = sizeof(buf);
                info.offset = 0;
                info.pos = 0;
                tinfo = ahd_fetch_transinfo(ahd, channel, ahd->our_id,
                                            target, &tstate);

                /*
                 * Don't bother reporting results while
                 * negotiations are still pending.
                 */
                if (tinfo->curr.period != tinfo->goal.period
                 || tinfo->curr.width != tinfo->goal.width
                 || tinfo->curr.offset != tinfo->goal.offset
                 || tinfo->curr.ppr_options != tinfo->goal.ppr_options)
                        if (bootverbose == 0)
                                break;

                /*
                 * Don't bother reporting results that
                 * are identical to those last reported.
                 */
                starget = ahd->platform_data->starget[target];
                targ = scsi_transport_target_data(starget);
                if (targ == NULL)
                        break;

                target_ppr_options =
                        (spi_dt(starget) ? MSG_EXT_PPR_DT_REQ : 0)
                        + (spi_qas(starget) ? MSG_EXT_PPR_QAS_REQ : 0)
                        + (spi_iu(starget) ?  MSG_EXT_PPR_IU_REQ : 0);

                if (tinfo->curr.period == spi_period(starget)
                    && tinfo->curr.width == spi_width(starget)
                    && tinfo->curr.offset == spi_offset(starget)
                 && tinfo->curr.ppr_options == target_ppr_options)
                        if (bootverbose == 0)
                                break;

                spi_period(starget) = tinfo->curr.period;
                spi_width(starget) = tinfo->curr.width;
                spi_offset(starget) = tinfo->curr.offset;
                spi_dt(starget) = tinfo->curr.ppr_options & MSG_EXT_PPR_DT_REQ ? 1 : 0;
                spi_qas(starget) = tinfo->curr.ppr_options & MSG_EXT_PPR_QAS_REQ ? 1 : 0;
                spi_iu(starget) = tinfo->curr.ppr_options & MSG_EXT_PPR_IU_REQ ? 1 : 0;
                spi_display_xfer_agreement(starget);
                break;
        }
        case AC_SENT_BDR:
        {
                WARN_ON(lun != CAM_LUN_WILDCARD);
                scsi_report_device_reset(ahd->platform_data->host,
                                         channel - 'A', target);
                break;
        }
        case AC_BUS_RESET:
                if (ahd->platform_data->host != NULL) {
                        scsi_report_bus_reset(ahd->platform_data->host,
                                              channel - 'A');
                }
                break;
        default:
                panic("ahd_send_async: Unexpected async event");
        }
}

/*
 * Calls the higher level scsi done function and frees the scb.
 */
void
ahd_done(struct ahd_softc *ahd, struct scb *scb)
{
        struct scsi_cmnd *cmd;
        struct    ahd_linux_device *dev;

        if ((scb->flags & SCB_ACTIVE) == 0) {
                printf("SCB %d done'd twice\n", SCB_GET_TAG(scb));
                ahd_dump_card_state(ahd);
                panic("Stopping for safety");
        }
        LIST_REMOVE(scb, pending_links);
        cmd = scb->io_ctx;
        dev = scb->platform_data->dev;
        dev->active--;
        dev->openings++;
        if ((cmd->result & (CAM_DEV_QFRZN << 16)) != 0) {
                cmd->result &= ~(CAM_DEV_QFRZN << 16);
                dev->qfrozen--;
        }
        ahd_linux_unmap_scb(ahd, scb);

        /*
         * Guard against stale sense data.
         * The Linux mid-layer assumes that sense
         * was retrieved anytime the first byte of
         * the sense buffer looks "sane".
         */
        cmd->sense_buffer[0] = 0;
        if (ahd_get_transaction_status(scb) == CAM_REQ_INPROG) {
                uint32_t amount_xferred;

                amount_xferred =
                    ahd_get_transfer_length(scb) - ahd_get_residual(scb);
                if ((scb->flags & SCB_TRANSMISSION_ERROR) != 0) {
#ifdef AHD_DEBUG
                        if ((ahd_debug & AHD_SHOW_MISC) != 0) {
                                ahd_print_path(ahd, scb);
                                printf("Set CAM_UNCOR_PARITY\n");
                        }
#endif
                        ahd_set_transaction_status(scb, CAM_UNCOR_PARITY);
#ifdef AHD_REPORT_UNDERFLOWS
                /*
                 * This code is disabled by default as some
                 * clients of the SCSI system do not properly
                 * initialize the underflow parameter.  This
                 * results in spurious termination of commands
                 * that complete as expected (e.g. underflow is
                 * allowed as command can return variable amounts
                 * of data.
                 */
                } else if (amount_xferred < scb->io_ctx->underflow) {
                        u_int i;

                        ahd_print_path(ahd, scb);
                        printf("CDB:");
                        for (i = 0; i < scb->io_ctx->cmd_len; i++)
                                printf(" 0x%x", scb->io_ctx->cmnd[i]);
                        printf("\n");
                        ahd_print_path(ahd, scb);
                        printf("Saw underflow (%ld of %ld bytes). "
                               "Treated as error\n",
                                ahd_get_residual(scb),
                                ahd_get_transfer_length(scb));
                        ahd_set_transaction_status(scb, CAM_DATA_RUN_ERR);
#endif
                } else {
                        ahd_set_transaction_status(scb, CAM_REQ_CMP);
                }
        } else if (ahd_get_transaction_status(scb) == CAM_SCSI_STATUS_ERROR) {
                ahd_linux_handle_scsi_status(ahd, cmd->device, scb);
        }

        if (dev->openings == 1
         && ahd_get_transaction_status(scb) == CAM_REQ_CMP
         && ahd_get_scsi_status(scb) != SCSI_STATUS_QUEUE_FULL)
                dev->tag_success_count++;
        /*
         * Some devices deal with temporary internal resource
         * shortages by returning queue full.  When the queue
         * full occurrs, we throttle back.  Slowly try to get
         * back to our previous queue depth.
         */
        if ((dev->openings + dev->active) < dev->maxtags
         && dev->tag_success_count > AHD_TAG_SUCCESS_INTERVAL) {
                dev->tag_success_count = 0;
                dev->openings++;
        }

        if (dev->active == 0)
                dev->commands_since_idle_or_otag = 0;

        if ((scb->flags & SCB_RECOVERY_SCB) != 0) {
                printf("Recovery SCB completes\n");
                if (ahd_get_transaction_status(scb) == CAM_BDR_SENT
                 || ahd_get_transaction_status(scb) == CAM_REQ_ABORTED)
                        ahd_set_transaction_status(scb, CAM_CMD_TIMEOUT);
                if ((ahd->platform_data->flags & AHD_SCB_UP_EH_SEM) != 0) {
                        ahd->platform_data->flags &= ~AHD_SCB_UP_EH_SEM;
                        up(&ahd->platform_data->eh_sem);
                }
        }

        ahd_free_scb(ahd, scb);
        ahd_linux_queue_cmd_complete(ahd, cmd);
}

static void
ahd_linux_handle_scsi_status(struct ahd_softc *ahd,
                             struct scsi_device *sdev, struct scb *scb)
{
        struct  ahd_devinfo devinfo;
        struct ahd_linux_device *dev = scsi_transport_device_data(sdev);

        ahd_compile_devinfo(&devinfo,
                            ahd->our_id,
                            sdev->sdev_target->id, sdev->lun,
                            sdev->sdev_target->channel == 0 ? 'A' : 'B',
                            ROLE_INITIATOR);
        
        /*
         * We don't currently trust the mid-layer to
         * properly deal with queue full or busy.  So,
         * when one occurs, we tell the mid-layer to
         * unconditionally requeue the command to us
         * so that we can retry it ourselves.  We also
         * implement our own throttling mechanism so
         * we don't clobber the device with too many
         * commands.
         */
        switch (ahd_get_scsi_status(scb)) {
        default:
                break;
        case SCSI_STATUS_CHECK_COND:
        case SCSI_STATUS_CMD_TERMINATED:
        {
                struct scsi_cmnd *cmd;

                /*
                 * Copy sense information to the OS's cmd
                 * structure if it is available.
                 */
                cmd = scb->io_ctx;
                if ((scb->flags & (SCB_SENSE|SCB_PKT_SENSE)) != 0) {
                        struct scsi_status_iu_header *siu;
                        u_int sense_size;
                        u_int sense_offset;

                        if (scb->flags & SCB_SENSE) {
                                sense_size = MIN(sizeof(struct scsi_sense_data)
                                               - ahd_get_sense_residual(scb),
                                                 sizeof(cmd->sense_buffer));
                                sense_offset = 0;
                        } else {
                                /*
                                 * Copy only the sense data into the provided
                                 * buffer.
                                 */
                                siu = (struct scsi_status_iu_header *)
                                    scb->sense_data;
                                sense_size = MIN(scsi_4btoul(siu->sense_length),
                                                sizeof(cmd->sense_buffer));
                                sense_offset = SIU_SENSE_OFFSET(siu);
                        }

                        memset(cmd->sense_buffer, 0, sizeof(cmd->sense_buffer));
                        memcpy(cmd->sense_buffer,
                               ahd_get_sense_buf(ahd, scb)
                               + sense_offset, sense_size);
                        cmd->result |= (DRIVER_SENSE << 24);

#ifdef AHD_DEBUG
                        if (ahd_debug & AHD_SHOW_SENSE) {
                                int i;

                                printf("Copied %d bytes of sense data at %d:",
                                       sense_size, sense_offset);
                                for (i = 0; i < sense_size; i++) {
                                        if ((i & 0xF) == 0)
                                                printf("\n");
                                        printf("0x%x ", cmd->sense_buffer[i]);
                                }
                                printf("\n");
                        }
#endif
                }
                break;
        }
        case SCSI_STATUS_QUEUE_FULL:
                /*
                 * By the time the core driver has returned this
                 * command, all other commands that were queued
                 * to us but not the device have been returned.
                 * This ensures that dev->active is equal to
                 * the number of commands actually queued to
                 * the device.
                 */
                dev->tag_success_count = 0;
                if (dev->active != 0) {
                        /*
                         * Drop our opening count to the number
                         * of commands currently outstanding.
                         */
                        dev->openings = 0;
#ifdef AHD_DEBUG
                        if ((ahd_debug & AHD_SHOW_QFULL) != 0) {
                                ahd_print_path(ahd, scb);
                                printf("Dropping tag count to %d\n",
                                       dev->active);
                        }
#endif
                        if (dev->active == dev->tags_on_last_queuefull) {

                                dev->last_queuefull_same_count++;
                                /*
                                 * If we repeatedly see a queue full
                                 * at the same queue depth, this
                                 * device has a fixed number of tag
                                 * slots.  Lock in this tag depth
                                 * so we stop seeing queue fulls from
                                 * this device.
                                 */
                                if (dev->last_queuefull_same_count
                                 == AHD_LOCK_TAGS_COUNT) {
                                        dev->maxtags = dev->active;
                                        ahd_print_path(ahd, scb);
                                        printf("Locking max tag count at %d\n",
                                               dev->active);
                                }
                        } else {
                                dev->tags_on_last_queuefull = dev->active;
                                dev->last_queuefull_same_count = 0;
                        }
                        ahd_set_transaction_status(scb, CAM_REQUEUE_REQ);
                        ahd_set_scsi_status(scb, SCSI_STATUS_OK);
                        ahd_platform_set_tags(ahd, &devinfo,
                                     (dev->flags & AHD_DEV_Q_BASIC)
                                   ? AHD_QUEUE_BASIC : AHD_QUEUE_TAGGED);
                        break;
                }
                /*
                 * Drop down to a single opening, and treat this
                 * as if the target returned BUSY SCSI status.
                 */
                dev->openings = 1;
                ahd_platform_set_tags(ahd, &devinfo,
                             (dev->flags & AHD_DEV_Q_BASIC)
                           ? AHD_QUEUE_BASIC : AHD_QUEUE_TAGGED);
                ahd_set_scsi_status(scb, SCSI_STATUS_BUSY);
        }
}

static void
ahd_linux_queue_cmd_complete(struct ahd_softc *ahd, struct scsi_cmnd *cmd)
{
        /*
         * Map CAM error codes into Linux Error codes.  We
         * avoid the conversion so that the DV code has the
         * full error information available when making
         * state change decisions.
         */
        {
                uint32_t status;
                u_int new_status;

                status = ahd_cmd_get_transaction_status(cmd);
                switch (status) {
                case CAM_REQ_INPROG:
                case CAM_REQ_CMP:
                case CAM_SCSI_STATUS_ERROR:
                        new_status = DID_OK;
                        break;
                case CAM_REQ_ABORTED:
                        new_status = DID_ABORT;
                        break;
                case CAM_BUSY:
                        new_status = DID_BUS_BUSY;
                        break;
                case CAM_REQ_INVALID:
                case CAM_PATH_INVALID:
                        new_status = DID_BAD_TARGET;
                        break;
                case CAM_SEL_TIMEOUT:
                        new_status = DID_NO_CONNECT;
                        break;
                case CAM_SCSI_BUS_RESET:
                case CAM_BDR_SENT:
                        new_status = DID_RESET;
                        break;
                case CAM_UNCOR_PARITY:
                        new_status = DID_PARITY;
                        break;
                case CAM_CMD_TIMEOUT:
                        new_status = DID_TIME_OUT;
                        break;
                case CAM_UA_ABORT:
                case CAM_REQ_CMP_ERR:
                case CAM_AUTOSENSE_FAIL:
                case CAM_NO_HBA:
                case CAM_DATA_RUN_ERR:
                case CAM_UNEXP_BUSFREE:
                case CAM_SEQUENCE_FAIL:
                case CAM_CCB_LEN_ERR:
                case CAM_PROVIDE_FAIL:
                case CAM_REQ_TERMIO:
                case CAM_UNREC_HBA_ERROR:
                case CAM_REQ_TOO_BIG:
                        new_status = DID_ERROR;
                        break;
                case CAM_REQUEUE_REQ:
                        new_status = DID_REQUEUE;
                        break;
                default:
                        /* We should never get here */
                        new_status = DID_ERROR;
                        break;
                }

                ahd_cmd_set_transaction_status(cmd, new_status);
        }

        cmd->scsi_done(cmd);
}

static void
ahd_linux_sem_timeout(u_long arg)
{
        struct  ahd_softc *ahd;
        u_long  s;

        ahd = (struct ahd_softc *)arg;

        ahd_lock(ahd, &s);
        if ((ahd->platform_data->flags & AHD_SCB_UP_EH_SEM) != 0) {
                ahd->platform_data->flags &= ~AHD_SCB_UP_EH_SEM;
                up(&ahd->platform_data->eh_sem);
        }
        ahd_unlock(ahd, &s);
}

void
ahd_freeze_simq(struct ahd_softc *ahd)
{
        ahd->platform_data->qfrozen++;
        if (ahd->platform_data->qfrozen == 1) {
                scsi_block_requests(ahd->platform_data->host);
                ahd_platform_abort_scbs(ahd, CAM_TARGET_WILDCARD, ALL_CHANNELS,
                                        CAM_LUN_WILDCARD, SCB_LIST_NULL,
                                        ROLE_INITIATOR, CAM_REQUEUE_REQ);
        }
}

void
ahd_release_simq(struct ahd_softc *ahd)
{
        u_long s;
        int    unblock_reqs;

        unblock_reqs = 0;
        ahd_lock(ahd, &s);
        if (ahd->platform_data->qfrozen > 0)
                ahd->platform_data->qfrozen--;
        if (ahd->platform_data->qfrozen == 0) {
                unblock_reqs = 1;
        }
        ahd_unlock(ahd, &s);
        /*
         * There is still a race here.  The mid-layer
         * should keep its own freeze count and use
         * a bottom half handler to run the queues
         * so we can unblock with our own lock held.
         */
        if (unblock_reqs)
                scsi_unblock_requests(ahd->platform_data->host);
}

static int
ahd_linux_queue_recovery_cmd(struct scsi_cmnd *cmd, scb_flag flag)
{
        struct ahd_softc *ahd;
        struct ahd_linux_device *dev;
        struct scb *pending_scb;
        u_int  saved_scbptr;
        u_int  active_scbptr;
        u_int  last_phase;
        u_int  saved_scsiid;
        u_int  cdb_byte;
        int    retval;
        int    was_paused;
        int    paused;
        int    wait;
        int    disconnected;
        ahd_mode_state saved_modes;

        pending_scb = NULL;
        paused = FALSE;
        wait = FALSE;
        ahd = *(struct ahd_softc **)cmd->device->host->hostdata;

        printf("%s:%d:%d:%d: Attempting to queue a%s message:",
               ahd_name(ahd), cmd->device->channel,
               cmd->device->id, cmd->device->lun,
               flag == SCB_ABORT ? "n ABORT" : " TARGET RESET");

        printf("CDB:");
        for (cdb_byte = 0; cdb_byte < cmd->cmd_len; cdb_byte++)
                printf(" 0x%x", cmd->cmnd[cdb_byte]);
        printf("\n");

        spin_lock_irq(&ahd->platform_data->spin_lock);

        /*
         * First determine if we currently own this command.
         * Start by searching the device queue.  If not found
         * there, check the pending_scb list.  If not found
         * at all, and the system wanted us to just abort the
         * command, return success.
         */
        dev = scsi_transport_device_data(cmd->device);

        if (dev == NULL) {
                /*
                 * No target device for this command exists,
                 * so we must not still own the command.
                 */
                printf("%s:%d:%d:%d: Is not an active device\n",
                       ahd_name(ahd), cmd->device->channel, cmd->device->id,
                       cmd->device->lun);
                retval = SUCCESS;
                goto no_cmd;
        }

        /*
         * See if we can find a matching cmd in the pending list.
         */
        LIST_FOREACH(pending_scb, &ahd->pending_scbs, pending_links) {
                if (pending_scb->io_ctx == cmd)
                        break;
        }

        if (pending_scb == NULL && flag == SCB_DEVICE_RESET) {

                /* Any SCB for this device will do for a target reset */
                LIST_FOREACH(pending_scb, &ahd->pending_scbs, pending_links) {
                        if (ahd_match_scb(ahd, pending_scb, cmd->device->id,
                                          cmd->device->channel + 'A',
                                          CAM_LUN_WILDCARD,
                                          SCB_LIST_NULL, ROLE_INITIATOR) == 0)
                                break;
                }
        }

        if (pending_scb == NULL) {
                printf("%s:%d:%d:%d: Command not found\n",
                       ahd_name(ahd), cmd->device->channel, cmd->device->id,
                       cmd->device->lun);
                goto no_cmd;
        }

        if ((pending_scb->flags & SCB_RECOVERY_SCB) != 0) {
                /*
                 * We can't queue two recovery actions using the same SCB
                 */
                retval = FAILED;
                goto  done;
        }

        /*
         * Ensure that the card doesn't do anything
         * behind our back.  Also make sure that we
         * didn't "just" miss an interrupt that would
         * affect this cmd.
         */
        was_paused = ahd_is_paused(ahd);
        ahd_pause_and_flushwork(ahd);
        paused = TRUE;

        if ((pending_scb->flags & SCB_ACTIVE) == 0) {
                printf("%s:%d:%d:%d: Command already completed\n",
                       ahd_name(ahd), cmd->device->channel, cmd->device->id,
                       cmd->device->lun);
                goto no_cmd;
        }

        printf("%s: At time of recovery, card was %spaused\n",
               ahd_name(ahd), was_paused ? "" : "not ");
        ahd_dump_card_state(ahd);

        disconnected = TRUE;
        if (flag == SCB_ABORT) {
                if (ahd_search_qinfifo(ahd, cmd->device->id, 
                                       cmd->device->channel + 'A',
                                       cmd->device->lun, 
                                       pending_scb->hscb->tag,
                                       ROLE_INITIATOR, CAM_REQ_ABORTED,
                                       SEARCH_COMPLETE) > 0) {
                        printf("%s:%d:%d:%d: Cmd aborted from QINFIFO\n",
                               ahd_name(ahd), cmd->device->channel, 
                               cmd->device->id, cmd->device->lun);
                        retval = SUCCESS;
                        goto done;
                }
        } else if (ahd_search_qinfifo(ahd, cmd->device->id,
                                      cmd->device->channel + 'A',
                                      cmd->device->lun, pending_scb->hscb->tag,
                                      ROLE_INITIATOR, /*status*/0,
                                      SEARCH_COUNT) > 0) {
                disconnected = FALSE;
        }

        saved_modes = ahd_save_modes(ahd);
        ahd_set_modes(ahd, AHD_MODE_SCSI, AHD_MODE_SCSI);
        last_phase = ahd_inb(ahd, LASTPHASE);
        saved_scbptr = ahd_get_scbptr(ahd);
        active_scbptr = saved_scbptr;
        if (disconnected && (ahd_inb(ahd, SEQ_FLAGS) & NOT_IDENTIFIED) == 0) {
                struct scb *bus_scb;

                bus_scb = ahd_lookup_scb(ahd, active_scbptr);
                if (bus_scb == pending_scb)
                        disconnected = FALSE;
                else if (flag != SCB_ABORT
                         && ahd_inb(ahd, SAVED_SCSIID) == pending_scb->hscb->scsiid
                         && ahd_inb(ahd, SAVED_LUN) == SCB_GET_LUN(pending_scb))
                        disconnected = FALSE;
        }

        /*
         * At this point, pending_scb is the scb associated with the
         * passed in command.  That command is currently active on the
         * bus or is in the disconnected state.
         */
        saved_scsiid = ahd_inb(ahd, SAVED_SCSIID);
        if (last_phase != P_BUSFREE
         && (SCB_GET_TAG(pending_scb) == active_scbptr
             || (flag == SCB_DEVICE_RESET
                 && SCSIID_TARGET(ahd, saved_scsiid) == cmd->device->id))) {

                /*
                 * We're active on the bus, so assert ATN
                 * and hope that the target responds.
                 */
                pending_scb = ahd_lookup_scb(ahd, active_scbptr);
                pending_scb->flags |= SCB_RECOVERY_SCB|flag;
                ahd_outb(ahd, MSG_OUT, HOST_MSG);
                ahd_outb(ahd, SCSISIGO, last_phase|ATNO);
                printf("%s:%d:%d:%d: Device is active, asserting ATN\n",
                       ahd_name(ahd), cmd->device->channel,
                       cmd->device->id, cmd->device->lun);
                wait = TRUE;
        } else if (disconnected) {

                /*
                 * Actually re-queue this SCB in an attempt
                 * to select the device before it reconnects.
                 */
                pending_scb->flags |= SCB_RECOVERY_SCB|SCB_ABORT;
                ahd_set_scbptr(ahd, SCB_GET_TAG(pending_scb));
                pending_scb->hscb->cdb_len = 0;
                pending_scb->hscb->task_attribute = 0;
                pending_scb->hscb->task_management = SIU_TASKMGMT_ABORT_TASK;

                if ((pending_scb->flags & SCB_PACKETIZED) != 0) {
                        /*
                         * Mark the SCB has having an outstanding
                         * task management function.  Should the command
                         * complete normally before the task management
                         * function can be sent, the host will be notified
                         * to abort our requeued SCB.
                         */
                        ahd_outb(ahd, SCB_TASK_MANAGEMENT,
                                 pending_scb->hscb->task_management);
                } else {
                        /*
                         * If non-packetized, set the MK_MESSAGE control
                         * bit indicating that we desire to send a message.
                         * We also set the disconnected flag since there is
                         * no guarantee that our SCB control byte matches
                         * the version on the card.  We don't want the
                         * sequencer to abort the command thinking an
                         * unsolicited reselection occurred.
                         */
                        pending_scb->hscb->control |= MK_MESSAGE|DISCONNECTED;

                        /*
                         * The sequencer will never re-reference the
                         * in-core SCB.  To make sure we are notified
                         * during reslection, set the MK_MESSAGE flag in
                         * the card's copy of the SCB.
                         */
                        ahd_outb(ahd, SCB_CONTROL,
                                 ahd_inb(ahd, SCB_CONTROL)|MK_MESSAGE);
                }

                /*
                 * Clear out any entries in the QINFIFO first
                 * so we are the next SCB for this target
                 * to run.
                 */
                ahd_search_qinfifo(ahd, cmd->device->id,
                                   cmd->device->channel + 'A', cmd->device->lun,
                                   SCB_LIST_NULL, ROLE_INITIATOR,
                                   CAM_REQUEUE_REQ, SEARCH_COMPLETE);
                ahd_qinfifo_requeue_tail(ahd, pending_scb);
                ahd_set_scbptr(ahd, saved_scbptr);
                ahd_print_path(ahd, pending_scb);
                printf("Device is disconnected, re-queuing SCB\n");
                wait = TRUE;
        } else {
                printf("%s:%d:%d:%d: Unable to deliver message\n",
                       ahd_name(ahd), cmd->device->channel,
                       cmd->device->id, cmd->device->lun);
                retval = FAILED;
                goto done;
        }

no_cmd:
        /*
         * Our assumption is that if we don't have the command, no
         * recovery action was required, so we return success.  Again,
         * the semantics of the mid-layer recovery engine are not
         * well defined, so this may change in time.
         */
        retval = SUCCESS;
done:
        if (paused)
                ahd_unpause(ahd);
        if (wait) {
                struct timer_list timer;
                int ret;

                ahd->platform_data->flags |= AHD_SCB_UP_EH_SEM;
                spin_unlock_irq(&ahd->platform_data->spin_lock);
                init_timer(&timer);
                timer.data = (u_long)ahd;
                timer.expires = jiffies + (5 * HZ);
                timer.function = ahd_linux_sem_timeout;
                add_timer(&timer);
                printf("Recovery code sleeping\n");
                down(&ahd->platform_data->eh_sem);
                printf("Recovery code awake\n");
                ret = del_timer_sync(&timer);
                if (ret == 0) {
                        printf("Timer Expired\n");
                        retval = FAILED;
                }
                spin_lock_irq(&ahd->platform_data->spin_lock);
        }
        spin_unlock_irq(&ahd->platform_data->spin_lock);
        return (retval);
}

static void ahd_linux_exit(void);

static void ahd_linux_set_xferflags(struct scsi_target *starget, unsigned int ppr_options, unsigned int period)
{
        spi_qas(starget) = (ppr_options & MSG_EXT_PPR_QAS_REQ)? 1 : 0;
        spi_dt(starget) = (ppr_options & MSG_EXT_PPR_DT_REQ)? 1 : 0;
        spi_iu(starget) = (ppr_options & MSG_EXT_PPR_IU_REQ) ? 1 : 0;
        spi_rd_strm(starget) = (ppr_options & MSG_EXT_PPR_RD_STRM) ? 1 : 0;
        spi_wr_flow(starget) = (ppr_options & MSG_EXT_PPR_WR_FLOW) ? 1 : 0;
        spi_pcomp_en(starget) = (ppr_options & MSG_EXT_PPR_PCOMP_EN) ? 1 : 0;
        spi_rti(starget) = (ppr_options & MSG_EXT_PPR_RTI) ? 1 : 0;
        spi_period(starget) = period;
}

static void ahd_linux_set_width(struct scsi_target *starget, int width)
{
        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
        struct ahd_softc *ahd = *((struct ahd_softc **)shost->hostdata);
        struct ahd_devinfo devinfo;
        unsigned long flags;

        ahd_compile_devinfo(&devinfo, shost->this_id, starget->id, 0,
                            starget->channel + 'A', ROLE_INITIATOR);
        ahd_lock(ahd, &flags);
        ahd_set_width(ahd, &devinfo, width, AHD_TRANS_GOAL, FALSE);
        ahd_unlock(ahd, &flags);
}

static void ahd_linux_set_period(struct scsi_target *starget, int period)
{
        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
        struct ahd_softc *ahd = *((struct ahd_softc **)shost->hostdata);
        struct ahd_tmode_tstate *tstate;
        struct ahd_initiator_tinfo *tinfo 
                = ahd_fetch_transinfo(ahd,
                                      starget->channel + 'A',
                                      shost->this_id, starget->id, &tstate);
        struct ahd_devinfo devinfo;
        unsigned int ppr_options = tinfo->goal.ppr_options;
        unsigned int dt;
        unsigned long flags;
        unsigned long offset = tinfo->goal.offset;

#ifdef AHD_DEBUG
        if ((ahd_debug & AHD_SHOW_DV) != 0)
                printf("%s: set period to %d\n", ahd_name(ahd), period);
#endif
        if (offset == 0)
                offset = MAX_OFFSET;

        if (period < 8)
                period = 8;
        if (period < 10) {
                ppr_options |= MSG_EXT_PPR_DT_REQ;
                if (period == 8)
                        ppr_options |= MSG_EXT_PPR_IU_REQ;
        }

        dt = ppr_options & MSG_EXT_PPR_DT_REQ;

        ahd_compile_devinfo(&devinfo, shost->this_id, starget->id, 0,
                            starget->channel + 'A', ROLE_INITIATOR);

        /* all PPR requests apart from QAS require wide transfers */
        if (ppr_options & ~MSG_EXT_PPR_QAS_REQ) {
                if (spi_width(starget) == 0)
                        ppr_options &= MSG_EXT_PPR_QAS_REQ;
        }

        ahd_find_syncrate(ahd, &period, &ppr_options,
                          dt ? AHD_SYNCRATE_MAX : AHD_SYNCRATE_ULTRA2);

        ahd_linux_set_xferflags(starget, ppr_options, period);

        ahd_lock(ahd, &flags);
        ahd_set_syncrate(ahd, &devinfo, period, offset,
                         ppr_options, AHD_TRANS_GOAL, FALSE);
        ahd_unlock(ahd, &flags);
}

static void ahd_linux_set_offset(struct scsi_target *starget, int offset)
{
        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
        struct ahd_softc *ahd = *((struct ahd_softc **)shost->hostdata);
        struct ahd_tmode_tstate *tstate;
        struct ahd_initiator_tinfo *tinfo 
                = ahd_fetch_transinfo(ahd,
                                      starget->channel + 'A',
                                      shost->this_id, starget->id, &tstate);
        struct ahd_devinfo devinfo;
        unsigned int ppr_options = 0;
        unsigned int period = 0;
        unsigned int dt = ppr_options & MSG_EXT_PPR_DT_REQ;
        unsigned long flags;

#ifdef AHD_DEBUG
        if ((ahd_debug & AHD_SHOW_DV) != 0)
                printf("%s: set offset to %d\n", ahd_name(ahd), offset);
#endif

        ahd_compile_devinfo(&devinfo, shost->this_id, starget->id, 0,
                            starget->channel + 'A', ROLE_INITIATOR);
        if (offset != 0) {
                period = tinfo->goal.period;
                ppr_options = tinfo->goal.ppr_options;
                ahd_find_syncrate(ahd, &period, &ppr_options, 
                                  dt ? AHD_SYNCRATE_MAX : AHD_SYNCRATE_ULTRA2);
        }
        ahd_linux_set_xferflags(starget, ppr_options, period);

        ahd_lock(ahd, &flags);
        ahd_set_syncrate(ahd, &devinfo, period, offset, ppr_options,
                         AHD_TRANS_GOAL, FALSE);
        ahd_unlock(ahd, &flags);
}

static void ahd_linux_set_dt(struct scsi_target *starget, int dt)
{
        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
        struct ahd_softc *ahd = *((struct ahd_softc **)shost->hostdata);
        struct ahd_tmode_tstate *tstate;
        struct ahd_initiator_tinfo *tinfo 
                = ahd_fetch_transinfo(ahd,
                                      starget->channel + 'A',
                                      shost->this_id, starget->id, &tstate);
        struct ahd_devinfo devinfo;
        unsigned int ppr_options = tinfo->goal.ppr_options
                & ~MSG_EXT_PPR_DT_REQ;
        unsigned int period = tinfo->goal.period;
        unsigned long flags;

#ifdef AHD_DEBUG
        if ((ahd_debug & AHD_SHOW_DV) != 0)
                printf("%s: %s DT\n", ahd_name(ahd), 
                       dt ? "enabling" : "disabling");
#endif
        if (dt) {
                ppr_options |= MSG_EXT_PPR_DT_REQ;
                if (period > 9)
                        period = 9; /* at least 12.5ns for DT */
        } else {
                if (period <= 9)
                        period = 10; /* If resetting DT, period must be >= 25ns */
                /* IU is invalid without DT set */
                ppr_options &= ~MSG_EXT_PPR_IU_REQ;
        }
        ahd_compile_devinfo(&devinfo, shost->this_id, starget->id, 0,
                            starget->channel + 'A', ROLE_INITIATOR);
        ahd_find_syncrate(ahd, &period, &ppr_options,
                          dt ? AHD_SYNCRATE_MAX : AHD_SYNCRATE_ULTRA2);

        ahd_linux_set_xferflags(starget, ppr_options, period);

        ahd_lock(ahd, &flags);
        ahd_set_syncrate(ahd, &devinfo, period, tinfo->goal.offset,
                         ppr_options, AHD_TRANS_GOAL, FALSE);
        ahd_unlock(ahd, &flags);
}

static void ahd_linux_set_qas(struct scsi_target *starget, int qas)
{
        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
        struct ahd_softc *ahd = *((struct ahd_softc **)shost->hostdata);
        struct ahd_tmode_tstate *tstate;
        struct ahd_initiator_tinfo *tinfo 
                = ahd_fetch_transinfo(ahd,
                                      starget->channel + 'A',
                                      shost->this_id, starget->id, &tstate);
        struct ahd_devinfo devinfo;
        unsigned int ppr_options = tinfo->goal.ppr_options
                & ~MSG_EXT_PPR_QAS_REQ;
        unsigned int period = tinfo->goal.period;
        unsigned int dt;
        unsigned long flags;

#ifdef AHD_DEBUG
        if ((ahd_debug & AHD_SHOW_DV) != 0)
                printf("%s: %s QAS\n", ahd_name(ahd), 
                       qas ? "enabling" : "disabling");
#endif

        if (qas) {
                ppr_options |= MSG_EXT_PPR_QAS_REQ; 
        }

        dt = ppr_options & MSG_EXT_PPR_DT_REQ;

        ahd_compile_devinfo(&devinfo, shost->this_id, starget->id, 0,
                            starget->channel + 'A', ROLE_INITIATOR);
        ahd_find_syncrate(ahd, &period, &ppr_options,
                          dt ? AHD_SYNCRATE_MAX : AHD_SYNCRATE_ULTRA2);

        spi_qas(starget) = (ppr_options & MSG_EXT_PPR_QAS_REQ)? 1 : 0;

        ahd_lock(ahd, &flags);
        ahd_set_syncrate(ahd, &devinfo, period, tinfo->goal.offset,
                         ppr_options, AHD_TRANS_GOAL, FALSE);
        ahd_unlock(ahd, &flags);
}

static void ahd_linux_set_iu(struct scsi_target *starget, int iu)
{
        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
        struct ahd_softc *ahd = *((struct ahd_softc **)shost->hostdata);
        struct ahd_tmode_tstate *tstate;
        struct ahd_initiator_tinfo *tinfo 
                = ahd_fetch_transinfo(ahd,
                                      starget->channel + 'A',
                                      shost->this_id, starget->id, &tstate);
        struct ahd_devinfo devinfo;
        unsigned int ppr_options = tinfo->goal.ppr_options
                & ~MSG_EXT_PPR_IU_REQ;
        unsigned int period = tinfo->goal.period;
        unsigned int dt;
        unsigned long flags;

#ifdef AHD_DEBUG
        if ((ahd_debug & AHD_SHOW_DV) != 0)
                printf("%s: %s IU\n", ahd_name(ahd),
                       iu ? "enabling" : "disabling");
#endif

        if (iu) {
                ppr_options |= MSG_EXT_PPR_IU_REQ;
                ppr_options |= MSG_EXT_PPR_DT_REQ; /* IU requires DT */
        }

        dt = ppr_options & MSG_EXT_PPR_DT_REQ;

        ahd_compile_devinfo(&devinfo, shost->this_id, starget->id, 0,
                            starget->channel + 'A', ROLE_INITIATOR);
        ahd_find_syncrate(ahd, &period, &ppr_options,
                          dt ? AHD_SYNCRATE_MAX : AHD_SYNCRATE_ULTRA2);

        ahd_linux_set_xferflags(starget, ppr_options, period);

        ahd_lock(ahd, &flags);
        ahd_set_syncrate(ahd, &devinfo, period, tinfo->goal.offset,
                         ppr_options, AHD_TRANS_GOAL, FALSE);
        ahd_unlock(ahd, &flags);
}

static void ahd_linux_set_rd_strm(struct scsi_target *starget, int rdstrm)
{
        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
        struct ahd_softc *ahd = *((struct ahd_softc **)shost->hostdata);
        struct ahd_tmode_tstate *tstate;
        struct ahd_initiator_tinfo *tinfo 
                = ahd_fetch_transinfo(ahd,
                                      starget->channel + 'A',
                                      shost->this_id, starget->id, &tstate);
        struct ahd_devinfo devinfo;
        unsigned int ppr_options = tinfo->goal.ppr_options
                & ~MSG_EXT_PPR_RD_STRM;
        unsigned int period = tinfo->goal.period;
        unsigned int dt = ppr_options & MSG_EXT_PPR_DT_REQ;
        unsigned long flags;

#ifdef AHD_DEBUG
        if ((ahd_debug & AHD_SHOW_DV) != 0)
                printf("%s: %s Read Streaming\n", ahd_name(ahd), 
                       rdstrm  ? "enabling" : "disabling");
#endif

        if (rdstrm)
                ppr_options |= MSG_EXT_PPR_RD_STRM;

        ahd_compile_devinfo(&devinfo, shost->this_id, starget->id, 0,
                            starget->channel + 'A', ROLE_INITIATOR);
        ahd_find_syncrate(ahd, &period, &ppr_options,
                          dt ? AHD_SYNCRATE_MAX : AHD_SYNCRATE_ULTRA2);

        spi_rd_strm(starget) = (ppr_options & MSG_EXT_PPR_RD_STRM) ? 1 : 0;

        ahd_lock(ahd, &flags);
        ahd_set_syncrate(ahd, &devinfo, period, tinfo->goal.offset,
                         ppr_options, AHD_TRANS_GOAL, FALSE);
        ahd_unlock(ahd, &flags);
}

static void ahd_linux_set_wr_flow(struct scsi_target *starget, int wrflow)
{
        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
        struct ahd_softc *ahd = *((struct ahd_softc **)shost->hostdata);
        struct ahd_tmode_tstate *tstate;
        struct ahd_initiator_tinfo *tinfo 
                = ahd_fetch_transinfo(ahd,
                                      starget->channel + 'A',
                                      shost->this_id, starget->id, &tstate);
        struct ahd_devinfo devinfo;
        unsigned int ppr_options = tinfo->goal.ppr_options
                & ~MSG_EXT_PPR_WR_FLOW;
        unsigned int period = tinfo->goal.period;
        unsigned int dt = ppr_options & MSG_EXT_PPR_DT_REQ;
        unsigned long flags;

#ifdef AHD_DEBUG
        if ((ahd_debug & AHD_SHOW_DV) != 0)
                printf("%s: %s Write Flow Control\n", ahd_name(ahd),
                       wrflow ? "enabling" : "disabling");
#endif

        if (wrflow)
                ppr_options |= MSG_EXT_PPR_WR_FLOW;

        ahd_compile_devinfo(&devinfo, shost->this_id, starget->id, 0,
                            starget->channel + 'A', ROLE_INITIATOR);
        ahd_find_syncrate(ahd, &period, &ppr_options,
                          dt ? AHD_SYNCRATE_MAX : AHD_SYNCRATE_ULTRA2);

        spi_wr_flow(starget) = (ppr_options & MSG_EXT_PPR_WR_FLOW) ? 1 : 0;

        ahd_lock(ahd, &flags);
        ahd_set_syncrate(ahd, &devinfo, period, tinfo->goal.offset,
                         ppr_options, AHD_TRANS_GOAL, FALSE);
        ahd_unlock(ahd, &flags);
}

static void ahd_linux_set_rti(struct scsi_target *starget, int rti)
{
        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
        struct ahd_softc *ahd = *((struct ahd_softc **)shost->hostdata);
        struct ahd_tmode_tstate *tstate;
        struct ahd_initiator_tinfo *tinfo 
                = ahd_fetch_transinfo(ahd,
                                      starget->channel + 'A',
                                      shost->this_id, starget->id, &tstate);
        struct ahd_devinfo devinfo;
        unsigned int ppr_options = tinfo->goal.ppr_options
                & ~MSG_EXT_PPR_RTI;
        unsigned int period = tinfo->goal.period;
        unsigned int dt = ppr_options & MSG_EXT_PPR_DT_REQ;
        unsigned long flags;

        if ((ahd->features & AHD_RTI) == 0) {
#ifdef AHD_DEBUG
                if ((ahd_debug & AHD_SHOW_DV) != 0)
                        printf("%s: RTI not available\n", ahd_name(ahd));
#endif
                return;
        }

#ifdef AHD_DEBUG
        if ((ahd_debug & AHD_SHOW_DV) != 0)
                printf("%s: %s RTI\n", ahd_name(ahd),
                       rti ? "enabling" : "disabling");
#endif

        if (rti)
                ppr_options |= MSG_EXT_PPR_RTI;

        ahd_compile_devinfo(&devinfo, shost->this_id, starget->id, 0,
                            starget->channel + 'A', ROLE_INITIATOR);
        ahd_find_syncrate(ahd, &period, &ppr_options,
                          dt ? AHD_SYNCRATE_MAX : AHD_SYNCRATE_ULTRA2);

        spi_rti(starget) = (ppr_options & MSG_EXT_PPR_RTI) ? 1 : 0;

        ahd_lock(ahd, &flags);
        ahd_set_syncrate(ahd, &devinfo, period, tinfo->goal.offset,
                         ppr_options, AHD_TRANS_GOAL, FALSE);
        ahd_unlock(ahd, &flags);
}

static void ahd_linux_set_pcomp_en(struct scsi_target *starget, int pcomp)
{
        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
        struct ahd_softc *ahd = *((struct ahd_softc **)shost->hostdata);
        struct ahd_tmode_tstate *tstate;
        struct ahd_initiator_tinfo *tinfo 
                = ahd_fetch_transinfo(ahd,
                                      starget->channel + 'A',
                                      shost->this_id, starget->id, &tstate);
        struct ahd_devinfo devinfo;
        unsigned int ppr_options = tinfo->goal.ppr_options
                & ~MSG_EXT_PPR_PCOMP_EN;
        unsigned int period = tinfo->goal.period;
        unsigned int dt = ppr_options & MSG_EXT_PPR_DT_REQ;
        unsigned long flags;

#ifdef AHD_DEBUG
        if ((ahd_debug & AHD_SHOW_DV) != 0)
                printf("%s: %s Precompensation\n", ahd_name(ahd), 
                       pcomp ? "Enable" : "Disable");
#endif

        if (pcomp)
                ppr_options |= MSG_EXT_PPR_PCOMP_EN;

        ahd_compile_devinfo(&devinfo, shost->this_id, starget->id, 0,
                            starget->channel + 'A', ROLE_INITIATOR);
        ahd_find_syncrate(ahd, &period, &ppr_options,
                          dt ? AHD_SYNCRATE_MAX : AHD_SYNCRATE_ULTRA2);

        spi_pcomp_en(starget) = (ppr_options & MSG_EXT_PPR_PCOMP_EN) ? 1 : 0;

        ahd_lock(ahd, &flags);
        ahd_set_syncrate(ahd, &devinfo, period, tinfo->goal.offset,
                         ppr_options, AHD_TRANS_GOAL, FALSE);
        ahd_unlock(ahd, &flags);
}

static struct spi_function_template ahd_linux_transport_functions = {
        .set_offset     = ahd_linux_set_offset,
        .show_offset    = 1,
        .set_period     = ahd_linux_set_period,
        .show_period    = 1,
        .set_width      = ahd_linux_set_width,
        .show_width     = 1,
        .set_dt         = ahd_linux_set_dt,
        .show_dt        = 1,
        .set_iu         = ahd_linux_set_iu,
        .show_iu        = 1,
        .set_qas        = ahd_linux_set_qas,
        .show_qas       = 1,
        .set_rd_strm    = ahd_linux_set_rd_strm,
        .show_rd_strm   = 1,
        .set_wr_flow    = ahd_linux_set_wr_flow,
        .show_wr_flow   = 1,
        .set_rti        = ahd_linux_set_rti,
        .show_rti       = 1,
        .set_pcomp_en   = ahd_linux_set_pcomp_en,
        .show_pcomp_en  = 1,
};



static int __init
ahd_linux_init(void)
{
        ahd_linux_transport_template = spi_attach_transport(&ahd_linux_transport_functions);
        if (!ahd_linux_transport_template)
                return -ENODEV;
        scsi_transport_reserve_target(ahd_linux_transport_template,
                                      sizeof(struct ahd_linux_target));
        scsi_transport_reserve_device(ahd_linux_transport_template,
                                      sizeof(struct ahd_linux_device));
        if (ahd_linux_detect(&aic79xx_driver_template) > 0)
                return 0;
        spi_release_transport(ahd_linux_transport_template);
        ahd_linux_exit();
        return -ENODEV;
}

static void __exit
ahd_linux_exit(void)
{
        ahd_linux_pci_exit();
        spi_release_transport(ahd_linux_transport_template);
}

module_init(ahd_linux_init);
module_exit(ahd_linux_exit);