[TG3]: Add tagged status support.

[linux-2.6/verdex.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>

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

#include <linux/init.h>         /* __setup */

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0)
#include "sd.h"                 /* For geometry detection */
#endif

#include <linux/mm.h>           /* For fetching system memory size */
#include <linux/delay.h>        /* For ssleep/msleep */

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

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0)
/* For dynamic sglist size calculation. */
u_int ahd_linux_nseg;
#endif

/*
 * 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}
};

/*
 * By default, read streaming is disabled.  In theory,
 * read streaming should enhance performance, but early
 * U320 drive firmware actually performs slower with
 * read streaming enabled.
 */
#ifdef CONFIG_AIC79XX_ENABLE_RD_STRM
#define AIC79XX_CONFIGED_RD_STRM 0xFFFF
#else
#define AIC79XX_CONFIGED_RD_STRM 0
#endif

static uint16_t aic79xx_rd_strm_info[] =
{
        AIC79XX_CONFIGED_RD_STRM,
        AIC79XX_CONFIGED_RD_STRM,
        AIC79XX_CONFIGED_RD_STRM,
        AIC79XX_CONFIGED_RD_STRM,
        AIC79XX_CONFIGED_RD_STRM,
        AIC79XX_CONFIGED_RD_STRM,
        AIC79XX_CONFIGED_RD_STRM,
        AIC79XX_CONFIGED_RD_STRM,
        AIC79XX_CONFIGED_RD_STRM,
        AIC79XX_CONFIGED_RD_STRM,
        AIC79XX_CONFIGED_RD_STRM,
        AIC79XX_CONFIGED_RD_STRM,
        AIC79XX_CONFIGED_RD_STRM,
        AIC79XX_CONFIGED_RD_STRM,
        AIC79XX_CONFIGED_RD_STRM,
        AIC79XX_CONFIGED_RD_STRM
};

/*
 * DV option:
 *
 * positive value = DV Enabled
 * zero           = DV Disabled
 * negative value = DV Default for adapter type/seeprom
 */
#ifdef CONFIG_AIC79XX_DV_SETTING
#define AIC79XX_CONFIGED_DV CONFIG_AIC79XX_DV_SETTING
#else
#define AIC79XX_CONFIGED_DV -1
#endif

static int8_t aic79xx_dv_settings[] =
{
        AIC79XX_CONFIGED_DV,
        AIC79XX_CONFIGED_DV,
        AIC79XX_CONFIGED_DV,
        AIC79XX_CONFIGED_DV,
        AIC79XX_CONFIGED_DV,
        AIC79XX_CONFIGED_DV,
        AIC79XX_CONFIGED_DV,
        AIC79XX_CONFIGED_DV,
        AIC79XX_CONFIGED_DV,
        AIC79XX_CONFIGED_DV,
        AIC79XX_CONFIGED_DV,
        AIC79XX_CONFIGED_DV,
        AIC79XX_CONFIGED_DV,
        AIC79XX_CONFIGED_DV,
        AIC79XX_CONFIGED_DV,
        AIC79XX_CONFIGED_DV
};

/*
 * 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, 0);
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"
"       rd_strm:<rd_strm_masks> Set per-target read streaming setting.\n"
"       dv:<dv_settings>        Set per-controller Domain Validation Setting.\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"
"       Sample /etc/modprobe.conf line:\n"
"               Change Read Streaming for Controller's 2 and 3\n"
"\n"
"       options aic79xx 'aic79xx=rd_strm:{..0xFFF0.0xC0F0}'");

static void ahd_linux_handle_scsi_status(struct ahd_softc *,
                                         struct ahd_linux_device *,
                                         struct scb *);
static void ahd_linux_queue_cmd_complete(struct ahd_softc *ahd,
                                         Scsi_Cmnd *cmd);
static void ahd_linux_filter_inquiry(struct ahd_softc *ahd,
                                     struct ahd_devinfo *devinfo);
static void ahd_linux_dev_timed_unfreeze(u_long arg);
static void ahd_linux_sem_timeout(u_long arg);
static void ahd_linux_initialize_scsi_bus(struct ahd_softc *ahd);
static void ahd_linux_size_nseg(void);
static void ahd_linux_thread_run_complete_queue(struct ahd_softc *ahd);
static void ahd_linux_start_dv(struct ahd_softc *ahd);
static void ahd_linux_dv_timeout(struct scsi_cmnd *cmd);
static int  ahd_linux_dv_thread(void *data);
static void ahd_linux_kill_dv_thread(struct ahd_softc *ahd);
static void ahd_linux_dv_target(struct ahd_softc *ahd, u_int target);
static void ahd_linux_dv_transition(struct ahd_softc *ahd,
                                    struct scsi_cmnd *cmd,
                                    struct ahd_devinfo *devinfo,
                                    struct ahd_linux_target *targ);
static void ahd_linux_dv_fill_cmd(struct ahd_softc *ahd,
                                  struct scsi_cmnd *cmd,
                                  struct ahd_devinfo *devinfo);
static void ahd_linux_dv_inq(struct ahd_softc *ahd,
                             struct scsi_cmnd *cmd,
                             struct ahd_devinfo *devinfo,
                             struct ahd_linux_target *targ,
                             u_int request_length);
static void ahd_linux_dv_tur(struct ahd_softc *ahd,
                             struct scsi_cmnd *cmd,
                             struct ahd_devinfo *devinfo);
static void ahd_linux_dv_rebd(struct ahd_softc *ahd,
                              struct scsi_cmnd *cmd,
                              struct ahd_devinfo *devinfo,
                              struct ahd_linux_target *targ);
static void ahd_linux_dv_web(struct ahd_softc *ahd,
                             struct scsi_cmnd *cmd,
                             struct ahd_devinfo *devinfo,
                             struct ahd_linux_target *targ);
static void ahd_linux_dv_reb(struct ahd_softc *ahd,
                             struct scsi_cmnd *cmd,
                             struct ahd_devinfo *devinfo,
                             struct ahd_linux_target *targ);
static void ahd_linux_dv_su(struct ahd_softc *ahd,
                            struct scsi_cmnd *cmd,
                            struct ahd_devinfo *devinfo,
                            struct ahd_linux_target *targ);
static int ahd_linux_fallback(struct ahd_softc *ahd,
                              struct ahd_devinfo *devinfo);
static __inline int ahd_linux_dv_fallback(struct ahd_softc *ahd,
                                          struct ahd_devinfo *devinfo);
static void ahd_linux_dv_complete(Scsi_Cmnd *cmd);
static void ahd_linux_generate_dv_pattern(struct ahd_linux_target *targ);
static u_int ahd_linux_user_tagdepth(struct ahd_softc *ahd,
                                     struct ahd_devinfo *devinfo);
static u_int ahd_linux_user_dv_setting(struct ahd_softc *ahd);
static void ahd_linux_setup_user_rd_strm_settings(struct ahd_softc *ahd);
static void ahd_linux_device_queue_depth(struct ahd_softc *ahd,
                                         struct ahd_linux_device *dev);
static struct ahd_linux_target* ahd_linux_alloc_target(struct ahd_softc*,
                                                       u_int, u_int);
static void                     ahd_linux_free_target(struct ahd_softc*,
                                                      struct ahd_linux_target*);
static struct ahd_linux_device* ahd_linux_alloc_device(struct ahd_softc*,
                                                       struct ahd_linux_target*,
                                                       u_int);
static void                     ahd_linux_free_device(struct ahd_softc*,
                                                      struct ahd_linux_device*);
static void ahd_linux_run_device_queue(struct ahd_softc*,
                                       struct ahd_linux_device*);
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_rd_strm_info;
static aic_option_callback_t ahd_linux_setup_dv;
static aic_option_callback_t ahd_linux_setup_iocell_info;
static int ahd_linux_next_unit(void);
static void ahd_runq_tasklet(unsigned long data);
static int aic79xx_setup(char *c);

/****************************** Inlines ***************************************/
static __inline void ahd_schedule_completeq(struct ahd_softc *ahd);
static __inline void ahd_schedule_runq(struct ahd_softc *ahd);
static __inline void ahd_setup_runq_tasklet(struct ahd_softc *ahd);
static __inline void ahd_teardown_runq_tasklet(struct ahd_softc *ahd);
static __inline struct ahd_linux_device*
                     ahd_linux_get_device(struct ahd_softc *ahd, u_int channel,
                                          u_int target, u_int lun, int alloc);
static struct ahd_cmd *ahd_linux_run_complete_queue(struct ahd_softc *ahd);
static __inline void ahd_linux_check_device_queue(struct ahd_softc *ahd,
                                                  struct ahd_linux_device *dev);
static __inline struct ahd_linux_device *
                     ahd_linux_next_device_to_run(struct ahd_softc *ahd);
static __inline void ahd_linux_run_device_queues(struct ahd_softc *ahd);
static __inline void ahd_linux_unmap_scb(struct ahd_softc*, struct scb*);

static __inline void
ahd_schedule_completeq(struct ahd_softc *ahd)
{
        if ((ahd->platform_data->flags & AHD_RUN_CMPLT_Q_TIMER) == 0) {
                ahd->platform_data->flags |= AHD_RUN_CMPLT_Q_TIMER;
                ahd->platform_data->completeq_timer.expires = jiffies;
                add_timer(&ahd->platform_data->completeq_timer);
        }
}

/*
 * Must be called with our lock held.
 */
static __inline void
ahd_schedule_runq(struct ahd_softc *ahd)
{
        tasklet_schedule(&ahd->platform_data->runq_tasklet);
}

static __inline
void ahd_setup_runq_tasklet(struct ahd_softc *ahd)
{
        tasklet_init(&ahd->platform_data->runq_tasklet, ahd_runq_tasklet,
                     (unsigned long)ahd);
}

static __inline void
ahd_teardown_runq_tasklet(struct ahd_softc *ahd)
{
        tasklet_kill(&ahd->platform_data->runq_tasklet);
}

static __inline struct ahd_linux_device*
ahd_linux_get_device(struct ahd_softc *ahd, u_int channel, u_int target,
                     u_int lun, int alloc)
{
        struct ahd_linux_target *targ;
        struct ahd_linux_device *dev;
        u_int target_offset;

        target_offset = target;
        if (channel != 0)
                target_offset += 8;
        targ = ahd->platform_data->targets[target_offset];
        if (targ == NULL) {
                if (alloc != 0) {
                        targ = ahd_linux_alloc_target(ahd, channel, target);
                        if (targ == NULL)
                                return (NULL);
                } else
                        return (NULL);
        }
        dev = targ->devices[lun];
        if (dev == NULL && alloc != 0)
                dev = ahd_linux_alloc_device(ahd, targ, lun);
        return (dev);
}

#define AHD_LINUX_MAX_RETURNED_ERRORS 4
static struct ahd_cmd *
ahd_linux_run_complete_queue(struct ahd_softc *ahd)
{       
        struct  ahd_cmd *acmd;
        u_long  done_flags;
        int     with_errors;

        with_errors = 0;
        ahd_done_lock(ahd, &done_flags);
        while ((acmd = TAILQ_FIRST(&ahd->platform_data->completeq)) != NULL) {
                Scsi_Cmnd *cmd;

                if (with_errors > AHD_LINUX_MAX_RETURNED_ERRORS) {
                        /*
                         * Linux uses stack recursion to requeue
                         * commands that need to be retried.  Avoid
                         * blowing out the stack by "spoon feeding"
                         * commands that completed with error back
                         * the operating system in case they are going
                         * to be retried. "ick"
                         */
                        ahd_schedule_completeq(ahd);
                        break;
                }
                TAILQ_REMOVE(&ahd->platform_data->completeq,
                             acmd, acmd_links.tqe);
                cmd = &acmd_scsi_cmd(acmd);
                cmd->host_scribble = NULL;
                if (ahd_cmd_get_transaction_status(cmd) != DID_OK
                 || (cmd->result & 0xFF) != SCSI_STATUS_OK)
                        with_errors++;

                cmd->scsi_done(cmd);
        }
        ahd_done_unlock(ahd, &done_flags);
        return (acmd);
}

static __inline void
ahd_linux_check_device_queue(struct ahd_softc *ahd,
                             struct ahd_linux_device *dev)
{
        if ((dev->flags & AHD_DEV_FREEZE_TIL_EMPTY) != 0
         && dev->active == 0) {
                dev->flags &= ~AHD_DEV_FREEZE_TIL_EMPTY;
                dev->qfrozen--;
        }

        if (TAILQ_FIRST(&dev->busyq) == NULL
         || dev->openings == 0 || dev->qfrozen != 0)
                return;

        ahd_linux_run_device_queue(ahd, dev);
}

static __inline struct ahd_linux_device *
ahd_linux_next_device_to_run(struct ahd_softc *ahd)
{
        
        if ((ahd->flags & AHD_RESOURCE_SHORTAGE) != 0
         || (ahd->platform_data->qfrozen != 0
          && AHD_DV_SIMQ_FROZEN(ahd) == 0))
                return (NULL);
        return (TAILQ_FIRST(&ahd->platform_data->device_runq));
}

static __inline void
ahd_linux_run_device_queues(struct ahd_softc *ahd)
{
        struct ahd_linux_device *dev;

        while ((dev = ahd_linux_next_device_to_run(ahd)) != NULL) {
                TAILQ_REMOVE(&ahd->platform_data->device_runq, dev, links);
                dev->flags &= ~AHD_DEV_ON_RUN_LIST;
                ahd_linux_check_device_queue(ahd, dev);
        }
}

static __inline void
ahd_linux_unmap_scb(struct ahd_softc *ahd, struct scb *scb)
{
        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)

/************************  Host template entry points *************************/
static int         ahd_linux_detect(Scsi_Host_Template *);
static const char *ahd_linux_info(struct Scsi_Host *);
static int         ahd_linux_queue(Scsi_Cmnd *, void (*)(Scsi_Cmnd *));
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
static int         ahd_linux_slave_alloc(Scsi_Device *);
static int         ahd_linux_slave_configure(Scsi_Device *);
static void        ahd_linux_slave_destroy(Scsi_Device *);
#if defined(__i386__)
static int         ahd_linux_biosparam(struct scsi_device*,
                                       struct block_device*, sector_t, int[]);
#endif
#else
static int         ahd_linux_release(struct Scsi_Host *);
static void        ahd_linux_select_queue_depth(struct Scsi_Host *host,
                                                Scsi_Device *scsi_devs);
#if defined(__i386__)
static int         ahd_linux_biosparam(Disk *, kdev_t, int[]);
#endif
#endif
static int         ahd_linux_bus_reset(Scsi_Cmnd *);
static int         ahd_linux_dev_reset(Scsi_Cmnd *);
static int         ahd_linux_abort(Scsi_Cmnd *);

/*
 * Calculate a safe value for AHD_NSEG (as expressed through ahd_linux_nseg).
 *
 * In pre-2.5.X...
 * The midlayer allocates an S/G array dynamically when a command is issued
 * using SCSI malloc.  This array, which is in an OS dependent format that
 * must later be copied to our private S/G list, is sized to house just the
 * number of segments needed for the current transfer.  Since the code that
 * sizes the SCSI malloc pool does not take into consideration fragmentation
 * of the pool, executing transactions numbering just a fraction of our
 * concurrent transaction limit with SG list lengths aproaching AHC_NSEG will
 * quickly depleat the SCSI malloc pool of usable space.  Unfortunately, the
 * mid-layer does not properly handle this scsi malloc failures for the S/G
 * array and the result can be a lockup of the I/O subsystem.  We try to size
 * our S/G list so that it satisfies our drivers allocation requirements in
 * addition to avoiding fragmentation of the SCSI malloc pool.
 */
static void
ahd_linux_size_nseg(void)
{
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0)
        u_int cur_size;
        u_int best_size;

        /*
         * The SCSI allocator rounds to the nearest 512 bytes
         * an cannot allocate across a page boundary.  Our algorithm
         * is to start at 1K of scsi malloc space per-command and
         * loop through all factors of the PAGE_SIZE and pick the best.
         */
        best_size = 0;
        for (cur_size = 1024; cur_size <= PAGE_SIZE; cur_size *= 2) {
                u_int nseg;

                nseg = cur_size / sizeof(struct scatterlist);
                if (nseg < AHD_LINUX_MIN_NSEG)
                        continue;

                if (best_size == 0) {
                        best_size = cur_size;
                        ahd_linux_nseg = nseg;
                } else {
                        u_int best_rem;
                        u_int cur_rem;

                        /*
                         * Compare the traits of the current "best_size"
                         * with the current size to determine if the
                         * current size is a better size.
                         */
                        best_rem = best_size % sizeof(struct scatterlist);
                        cur_rem = cur_size % sizeof(struct scatterlist);
                        if (cur_rem < best_rem) {
                                best_size = cur_size;
                                ahd_linux_nseg = nseg;
                        }
                }
        }
#endif
}

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

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0)
        /*
         * It is a bug that the upper layer takes
         * this lock just prior to calling us.
         */
        spin_unlock_irq(&io_request_lock);
#endif

        /*
         * Sanity checking of Linux SCSI data structures so
         * that some of our hacks^H^H^H^H^Hassumptions aren't
         * violated.
         */
        if (offsetof(struct ahd_cmd_internal, end)
          > offsetof(struct scsi_cmnd, host_scribble)) {
                printf("ahd_linux_detect: SCSI data structures changed.\n");
                printf("ahd_linux_detect: Unable to attach\n");
                return (0);
        }
        /*
         * Determine an appropriate size for our Scatter Gatther lists.
         */
        ahd_linux_size_nseg();
#ifdef MODULE
        /*
         * If we've been passed any parameters, process them now.
         */
        if (aic79xx)
                aic79xx_setup(aic79xx);
#endif

        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++;
        }
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0)
        spin_lock_irq(&io_request_lock);
#endif
        aic79xx_detect_complete++;
        return 0;
}

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0)
/*
 * Free the passed in Scsi_Host memory structures prior to unloading the
 * module.
 */
static int
ahd_linux_release(struct Scsi_Host * host)
{
        struct ahd_softc *ahd;
        u_long l;

        ahd_list_lock(&l);
        if (host != NULL) {

                /*
                 * We should be able to just perform
                 * the free directly, but check our
                 * list for extra sanity.
                 */
                ahd = ahd_find_softc(*(struct ahd_softc **)host->hostdata);
                if (ahd != NULL) {
                        u_long s;

                        ahd_lock(ahd, &s);
                        ahd_intr_enable(ahd, FALSE);
                        ahd_unlock(ahd, &s);
                        ahd_free(ahd);
                }
        }
        ahd_list_unlock(&l);
        return (0);
}
#endif

/*
 * 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(Scsi_Cmnd * cmd, void (*scsi_done) (Scsi_Cmnd *))
{
        struct   ahd_softc *ahd;
        struct   ahd_linux_device *dev;
        u_long   flags;

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

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

        ahd_midlayer_entrypoint_lock(ahd, &flags);

        /*
         * 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
         && AHD_DV_CMD(cmd) == 0) {

                ahd_cmd_set_transaction_status(cmd, CAM_REQUEUE_REQ);
                ahd_linux_queue_cmd_complete(ahd, cmd);
                ahd_schedule_completeq(ahd);
                ahd_midlayer_entrypoint_unlock(ahd, &flags);
                return (0);
        }
        dev = ahd_linux_get_device(ahd, cmd->device->channel,
                                   cmd->device->id, cmd->device->lun,
                                   /*alloc*/TRUE);
        if (dev == NULL) {
                ahd_cmd_set_transaction_status(cmd, CAM_RESRC_UNAVAIL);
                ahd_linux_queue_cmd_complete(ahd, cmd);
                ahd_schedule_completeq(ahd);
                ahd_midlayer_entrypoint_unlock(ahd, &flags);
                printf("%s: aic79xx_linux_queue - Unable to allocate device!\n",
                       ahd_name(ahd));
                return (0);
        }
        if (cmd->cmd_len > MAX_CDB_LEN)
                return (-EINVAL);
        cmd->result = CAM_REQ_INPROG << 16;
        TAILQ_INSERT_TAIL(&dev->busyq, (struct ahd_cmd *)cmd, acmd_links.tqe);
        if ((dev->flags & AHD_DEV_ON_RUN_LIST) == 0) {
                TAILQ_INSERT_TAIL(&ahd->platform_data->device_runq, dev, links);
                dev->flags |= AHD_DEV_ON_RUN_LIST;
                ahd_linux_run_device_queues(ahd);
        }
        ahd_midlayer_entrypoint_unlock(ahd, &flags);
        return (0);
}

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
static int
ahd_linux_slave_alloc(Scsi_Device *device)
{
        struct  ahd_softc *ahd;

        ahd = *((struct ahd_softc **)device->host->hostdata);
        if (bootverbose)
                printf("%s: Slave Alloc %d\n", ahd_name(ahd), device->id);
        return (0);
}

static int
ahd_linux_slave_configure(Scsi_Device *device)
{
        struct  ahd_softc *ahd;
        struct  ahd_linux_device *dev;
        u_long  flags;

        ahd = *((struct ahd_softc **)device->host->hostdata);
        if (bootverbose)
                printf("%s: Slave Configure %d\n", ahd_name(ahd), device->id);
        ahd_midlayer_entrypoint_lock(ahd, &flags);
        /*
         * Since Linux has attached to the device, configure
         * it so we don't free and allocate the device
         * structure on every command.
         */
        dev = ahd_linux_get_device(ahd, device->channel,
                                   device->id, device->lun,
                                   /*alloc*/TRUE);
        if (dev != NULL) {
                dev->flags &= ~AHD_DEV_UNCONFIGURED;
                dev->flags |= AHD_DEV_SLAVE_CONFIGURED;
                dev->scsi_device = device;
                ahd_linux_device_queue_depth(ahd, dev);
        }
        ahd_midlayer_entrypoint_unlock(ahd, &flags);
        return (0);
}

static void
ahd_linux_slave_destroy(Scsi_Device *device)
{
        struct  ahd_softc *ahd;
        struct  ahd_linux_device *dev;
        u_long  flags;

        ahd = *((struct ahd_softc **)device->host->hostdata);
        if (bootverbose)
                printf("%s: Slave Destroy %d\n", ahd_name(ahd), device->id);
        ahd_midlayer_entrypoint_lock(ahd, &flags);
        dev = ahd_linux_get_device(ahd, device->channel,
                                   device->id, device->lun,
                                           /*alloc*/FALSE);

        /*
         * Filter out "silly" deletions of real devices by only
         * deleting devices that have had slave_configure()
         * called on them.  All other devices that have not
         * been configured will automatically be deleted by
         * the refcounting process.
         */
        if (dev != NULL
         && (dev->flags & AHD_DEV_SLAVE_CONFIGURED) != 0) {
                dev->flags |= AHD_DEV_UNCONFIGURED;
                if (TAILQ_EMPTY(&dev->busyq)
                 && dev->active == 0
                 && (dev->flags & AHD_DEV_TIMER_ACTIVE) == 0)
                        ahd_linux_free_device(ahd, dev);
        }
        ahd_midlayer_entrypoint_unlock(ahd, &flags);
}
#else
/*
 * Sets the queue depth for each SCSI device hanging
 * off the input host adapter.
 */
static void
ahd_linux_select_queue_depth(struct Scsi_Host * host,
                             Scsi_Device * scsi_devs)
{
        Scsi_Device *device;
        Scsi_Device *ldev;
        struct  ahd_softc *ahd;
        u_long  flags;

        ahd = *((struct ahd_softc **)host->hostdata);
        ahd_lock(ahd, &flags);
        for (device = scsi_devs; device != NULL; device = device->next) {

                /*
                 * Watch out for duplicate devices.  This works around
                 * some quirks in how the SCSI scanning code does its
                 * device management.
                 */
                for (ldev = scsi_devs; ldev != device; ldev = ldev->next) {
                        if (ldev->host == device->host
                         && ldev->channel == device->channel
                         && ldev->id == device->id
                         && ldev->lun == device->lun)
                                break;
                }
                /* Skip duplicate. */
                if (ldev != device)
                        continue;

                if (device->host == host) {
                        struct   ahd_linux_device *dev;

                        /*
                         * Since Linux has attached to the device, configure
                         * it so we don't free and allocate the device
                         * structure on every command.
                         */
                        dev = ahd_linux_get_device(ahd, device->channel,
                                                   device->id, device->lun,
                                                   /*alloc*/TRUE);
                        if (dev != NULL) {
                                dev->flags &= ~AHD_DEV_UNCONFIGURED;
                                dev->scsi_device = device;
                                ahd_linux_device_queue_depth(ahd, dev);
                                device->queue_depth = dev->openings
                                                    + dev->active;
                                if ((dev->flags & (AHD_DEV_Q_BASIC
                                                | AHD_DEV_Q_TAGGED)) == 0) {
                                        /*
                                         * 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.
                                         */
                                        device->queue_depth = 2;
                                }
                        }
                }
        }
        ahd_unlock(ahd, &flags);
}
#endif

#if defined(__i386__)
/*
 * Return the disk geometry for the given SCSI device.
 */
static int
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
ahd_linux_biosparam(struct scsi_device *sdev, struct block_device *bdev,
                    sector_t capacity, int geom[])
{
        uint8_t *bh;
#else
ahd_linux_biosparam(Disk *disk, kdev_t dev, int geom[])
{
        struct  scsi_device *sdev = disk->device;
        u_long  capacity = disk->capacity;
        struct  buffer_head *bh;
#endif
        int      heads;
        int      sectors;
        int      cylinders;
        int      ret;
        int      extended;
        struct   ahd_softc *ahd;

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

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
        bh = scsi_bios_ptable(bdev);
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,17)
        bh = bread(MKDEV(MAJOR(dev), MINOR(dev) & ~0xf), 0, block_size(dev));
#else
        bh = bread(MKDEV(MAJOR(dev), MINOR(dev) & ~0xf), 0, 1024);
#endif

        if (bh) {
                ret = scsi_partsize(bh, capacity,
                                    &geom[2], &geom[0], &geom[1]);
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
                kfree(bh);
#else
                brelse(bh);
#endif
                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(Scsi_Cmnd *cmd)
{
        struct ahd_softc *ahd;
        struct ahd_cmd *acmd;
        struct ahd_cmd *list_acmd;
        struct ahd_linux_device *dev;
        struct scb *pending_scb;
        u_long s;
        u_int  saved_scbptr;
        u_int  active_scbptr;
        u_int  last_phase;
        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;
        acmd = (struct ahd_cmd *)cmd;

        printf("%s:%d:%d:%d: Attempting to abort cmd %p:",
               ahd_name(ahd), cmd->device->channel, cmd->device->id,
               cmd->device->lun, cmd);
        for (cdb_byte = 0; cdb_byte < cmd->cmd_len; cdb_byte++)
                printf(" 0x%x", cmd->cmnd[cdb_byte]);
        printf("\n");

        /*
         * In all versions of Linux, we have to work around
         * a major flaw in how the mid-layer is locked down
         * if we are to sleep successfully in our error handler
         * while allowing our interrupt handler to run.  Since
         * the midlayer acquires either the io_request_lock or
         * our lock prior to calling us, we must use the
         * spin_unlock_irq() method for unlocking our lock.
         * This will force interrupts to be enabled on the
         * current CPU.  Since the EH thread should not have
         * been running with CPU interrupts disabled other than
         * by acquiring either the io_request_lock or our own
         * lock, this *should* be safe.
         */
        ahd_midlayer_entrypoint_lock(ahd, &s);

        /*
         * 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 = ahd_linux_get_device(ahd, cmd->device->channel,
                                   cmd->device->id, cmd->device->lun,
                                   /*alloc*/FALSE);

        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;
        }

        TAILQ_FOREACH(list_acmd, &dev->busyq, acmd_links.tqe) {
                if (list_acmd == acmd)
                        break;
        }

        if (list_acmd != NULL) {
                printf("%s:%d:%d:%d: Command found on device queue\n",
                       ahd_name(ahd), cmd->device->channel, cmd->device->id,
                       cmd->device->lun);
                TAILQ_REMOVE(&dev->busyq, list_acmd, acmd_links.tqe);
                cmd->result = DID_ABORT << 16;
                ahd_linux_queue_cmd_complete(ahd, cmd);
                retval = SUCCESS;
                goto done;
        }

        /*
         * 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) {
                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 (ahd_search_qinfifo(ahd, cmd->device->id, cmd->device->channel + 'A',
                               cmd->device->lun, SCB_GET_TAG(pending_scb),
                               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;
        }

        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;
        }

        /*
         * 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.
         */
        if (last_phase != P_BUSFREE
         && SCB_GET_TAG(pending_scb) == active_scbptr) {

                /*
                 * 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|SCB_ABORT;
                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;

                pending_scb->platform_data->flags |= AHD_SCB_UP_EH_SEM;
                spin_unlock_irq(&ahd->platform_data->spin_lock);
                init_timer(&timer);
                timer.data = (u_long)pending_scb;
                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);
        }
        ahd_schedule_runq(ahd);
        ahd_linux_run_complete_queue(ahd);
        ahd_midlayer_entrypoint_unlock(ahd, &s);
        return (retval);
}


static void
ahd_linux_dev_reset_complete(Scsi_Cmnd *cmd)
{
        free(cmd, M_DEVBUF);
}

/*
 * Attempt to send a target reset message to the device that timed out.
 */
static int
ahd_linux_dev_reset(Scsi_Cmnd *cmd)
{
        struct  ahd_softc *ahd;
        struct  scsi_cmnd *recovery_cmd;
        struct  ahd_linux_device *dev;
        struct  ahd_initiator_tinfo *tinfo;
        struct  ahd_tmode_tstate *tstate;
        struct  scb *scb;
        struct  hardware_scb *hscb;
        u_long  s;
        struct  timer_list timer;
        int     retval;

        ahd = *(struct ahd_softc **)cmd->device->host->hostdata;
        recovery_cmd = malloc(sizeof(struct scsi_cmnd), M_DEVBUF, M_WAITOK);
        if (!recovery_cmd)
                return (FAILED);
        memset(recovery_cmd, 0, sizeof(struct scsi_cmnd));
        recovery_cmd->device = cmd->device;
        recovery_cmd->scsi_done = ahd_linux_dev_reset_complete;
#if AHD_DEBUG
        if ((ahd_debug & AHD_SHOW_RECOVERY) != 0)
                printf("%s:%d:%d:%d: Device reset called for cmd %p\n",
                       ahd_name(ahd), cmd->device->channel, cmd->device->id,
                       cmd->device->lun, cmd);
#endif
        ahd_midlayer_entrypoint_lock(ahd, &s);

        dev = ahd_linux_get_device(ahd, cmd->device->channel, cmd->device->id,
                                   cmd->device->lun, /*alloc*/FALSE);
        if (dev == NULL) {
                ahd_midlayer_entrypoint_unlock(ahd, &s);
                kfree(recovery_cmd);
                return (FAILED);
        }
        if ((scb = ahd_get_scb(ahd, AHD_NEVER_COL_IDX)) == NULL) {
                ahd_midlayer_entrypoint_unlock(ahd, &s);
                kfree(recovery_cmd);
                return (FAILED);
        }
        tinfo = ahd_fetch_transinfo(ahd, 'A', ahd->our_id,
                                    cmd->device->id, &tstate);
        recovery_cmd->result = CAM_REQ_INPROG << 16;
        recovery_cmd->host_scribble = (char *)scb;
        scb->io_ctx = recovery_cmd;
        scb->platform_data->dev = dev;
        scb->sg_count = 0;
        ahd_set_residual(scb, 0);
        ahd_set_sense_residual(scb, 0);
        hscb = scb->hscb;
        hscb->control = 0;
        hscb->scsiid = BUILD_SCSIID(ahd, cmd);
        hscb->lun = cmd->device->lun;
        hscb->cdb_len = 0;
        hscb->task_management = SIU_TASKMGMT_LUN_RESET;
        scb->flags |= SCB_DEVICE_RESET|SCB_RECOVERY_SCB|SCB_ACTIVE;
        if ((tinfo->curr.ppr_options & MSG_EXT_PPR_IU_REQ) != 0) {
                scb->flags |= SCB_PACKETIZED;
        } else {
                hscb->control |= MK_MESSAGE;
        }
        dev->openings--;
        dev->active++;
        dev->commands_issued++;
        LIST_INSERT_HEAD(&ahd->pending_scbs, scb, pending_links);
        ahd_queue_scb(ahd, scb);

        scb->platform_data->flags |= AHD_SCB_UP_EH_SEM;
        spin_unlock_irq(&ahd->platform_data->spin_lock);
        init_timer(&timer);
        timer.data = (u_long)scb;
        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");
        retval = SUCCESS;
        if (del_timer_sync(&timer) == 0) {
                printf("Timer Expired\n");
                retval = FAILED;
        }
        spin_lock_irq(&ahd->platform_data->spin_lock);
        ahd_schedule_runq(ahd);
        ahd_linux_run_complete_queue(ahd);
        ahd_midlayer_entrypoint_unlock(ahd, &s);
        printf("%s: Device reset returning 0x%x\n", ahd_name(ahd), retval);
        return (retval);
}

/*
 * Reset the SCSI bus.
 */
static int
ahd_linux_bus_reset(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_midlayer_entrypoint_lock(ahd, &s);
        found = ahd_reset_channel(ahd, cmd->device->channel + 'A',
                                  /*initiate reset*/TRUE);
        ahd_linux_run_complete_queue(ahd);
        ahd_midlayer_entrypoint_unlock(ahd, &s);

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

        return (SUCCESS);
}

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,
};

/**************************** Tasklet Handler *********************************/

/*
 * In 2.4.X and above, this routine is called from a tasklet,
 * so we must re-acquire our lock prior to executing this code.
 * In all prior kernels, ahd_schedule_runq() calls this routine
 * directly and ahd_schedule_runq() is called with our lock held.
 */
static void
ahd_runq_tasklet(unsigned long data)
{
        struct ahd_softc* ahd;
        struct ahd_linux_device *dev;
        u_long flags;

        ahd = (struct ahd_softc *)data;
        ahd_lock(ahd, &flags);
        while ((dev = ahd_linux_next_device_to_run(ahd)) != NULL) {
        
                TAILQ_REMOVE(&ahd->platform_data->device_runq, dev, links);
                dev->flags &= ~AHD_DEV_ON_RUN_LIST;
                ahd_linux_check_device_queue(ahd, dev);
                /* Yeild to our interrupt handler */
                ahd_unlock(ahd, &flags);
                ahd_lock(ahd, &flags);
        }
        ahd_unlock(ahd, &flags);
}

/******************************** 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)
{
        bus_dmamap_t map;

        map = malloc(sizeof(*map), M_DEVBUF, M_NOWAIT);
        if (map == NULL)
                return (ENOMEM);
        /*
         * Although we can dma data above 4GB, our
         * "consistent" memory is below 4GB for
         * space efficiency reasons (only need a 4byte
         * address).  For this reason, we have to reset
         * our dma mask when doing allocations.
         */
        if (ahd->dev_softc != NULL)
                if (pci_set_dma_mask(ahd->dev_softc, 0xFFFFFFFF)) {
                        printk(KERN_WARNING "aic79xx: No suitable DMA available.\n");
                        kfree(map);
                        return (ENODEV);
                }
        *vaddr = pci_alloc_consistent(ahd->dev_softc,
                                      dmat->maxsize, &map->bus_addr);
        if (ahd->dev_softc != NULL)
                if (pci_set_dma_mask(ahd->dev_softc,
                                     ahd->platform_data->hw_dma_mask)) {
                        printk(KERN_WARNING "aic79xx: No suitable DMA available.\n");
                        kfree(map);
                        return (ENODEV);
                }
        if (*vaddr == NULL)
                return (ENOMEM);
        *mapp = map;
        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->bus_addr);
}

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->bus_addr;
        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)
{
        /*
         * The map may is NULL in our < 2.3.X implementation.
         */
        if (map != NULL)
                free(map, M_DEVBUF);
}

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_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);
        }
}

static void
ahd_linux_setup_rd_strm_info(u_long arg, int instance, int targ, int32_t value)
{
        if ((instance >= 0)
         && (instance < NUM_ELEMENTS(aic79xx_rd_strm_info))) {
                aic79xx_rd_strm_info[instance] = value & 0xFFFF;
                if (bootverbose)
                        printf("rd_strm[%d] = 0x%x\n", instance, value);
        }
}

static void
ahd_linux_setup_dv(u_long arg, int instance, int targ, int32_t value)
{
        if ((instance >= 0)
         && (instance < NUM_ELEMENTS(aic79xx_dv_settings))) {
                aic79xx_dv_settings[instance] = value;
                if (bootverbose)
                        printf("dv[%d] = %d\n", instance, 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;
                }
        }
}

/*
 * 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},
                { "rd_strm", NULL },
                { "dv", 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, "rd_strm", n) == 0) {
                        s = aic_parse_brace_option("rd_strm", p + n, end,
                            1, ahd_linux_setup_rd_strm_info, 0);
                } else if (strncmp(p, "dv", n) == 0) {
                        s = aic_parse_brace_option("dv", p + n, end, 1,
                            ahd_linux_setup_dv, 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, Scsi_Host_Template *template)
{
        char    buf[80];
        struct  Scsi_Host *host;
        char    *new_name;
        u_long  s;
        u_long  target;

        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);
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
        scsi_assign_lock(host, &ahd->platform_data->spin_lock);
#elif AHD_SCSI_HAS_HOST_LOCK != 0
        host->lock = &ahd->platform_data->spin_lock;
#endif
        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;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0)
        scsi_set_pci_device(host, ahd->dev_softc);
#endif
        ahd_linux_setup_user_rd_strm_settings(ahd);
        ahd_linux_initialize_scsi_bus(ahd);
        ahd_unlock(ahd, &s);
        ahd->platform_data->dv_pid = kernel_thread(ahd_linux_dv_thread, ahd, 0);
        ahd_lock(ahd, &s);
        if (ahd->platform_data->dv_pid < 0) {
                printf("%s: Failed to create DV thread, error= %d\n",
                       ahd_name(ahd), ahd->platform_data->dv_pid);
                return (-ahd->platform_data->dv_pid);
        }
        /*
         * Initially allocate *all* of our linux target objects
         * so that the DV thread will scan them all in parallel
         * just after driver initialization.  Any device that
         * does not exist will have its target object destroyed
         * by the selection timeout handler.  In the case of a
         * device that appears after the initial DV scan, async
         * negotiation will occur for the first command, and DV
         * will comence should that first command be successful.
         */
        for (target = 0; target < host->max_id; target++) {

                /*
                 * Skip our own ID.  Some Compaq/HP storage devices
                 * have enclosure management devices that respond to
                 * single bit selection (i.e. selecting ourselves).
                 * It is expected that either an external application
                 * or a modified kernel will be used to probe this
                 * ID if it is appropriate.  To accommodate these
                 * installations, ahc_linux_alloc_target() will allocate
                 * for our ID if asked to do so.
                 */
                if (target == ahd->our_id) 
                        continue;

                ahd_linux_alloc_target(ahd, 0, target);
        }
        ahd_intr_enable(ahd, TRUE);
        ahd_linux_start_dv(ahd);
        ahd_unlock(ahd, &s);

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
        scsi_add_host(host, &ahd->dev_softc->dev); /* XXX handle failure */
        scsi_scan_host(host);
#endif
        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));
        TAILQ_INIT(&ahd->platform_data->completeq);
        TAILQ_INIT(&ahd->platform_data->device_runq);
        ahd->platform_data->irq = AHD_LINUX_NOIRQ;
        ahd->platform_data->hw_dma_mask = 0xFFFFFFFF;
        ahd_lockinit(ahd);
        ahd_done_lockinit(ahd);
        init_timer(&ahd->platform_data->completeq_timer);
        ahd->platform_data->completeq_timer.data = (u_long)ahd;
        ahd->platform_data->completeq_timer.function =
            (ahd_linux_callback_t *)ahd_linux_thread_run_complete_queue;
        init_MUTEX_LOCKED(&ahd->platform_data->eh_sem);
        init_MUTEX_LOCKED(&ahd->platform_data->dv_sem);
        init_MUTEX_LOCKED(&ahd->platform_data->dv_cmd_sem);
        ahd_setup_runq_tasklet(ahd);
        ahd->seltime = (aic79xx_seltime & 0x3) << 4;
        return (0);
}

void
ahd_platform_free(struct ahd_softc *ahd)
{
        struct ahd_linux_target *targ;
        struct ahd_linux_device *dev;
        int i, j;

        if (ahd->platform_data != NULL) {
                del_timer_sync(&ahd->platform_data->completeq_timer);
                ahd_linux_kill_dv_thread(ahd);
                ahd_teardown_runq_tasklet(ahd);
                if (ahd->platform_data->host != NULL) {
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
                        scsi_remove_host(ahd->platform_data->host);
#endif
                        scsi_host_put(ahd->platform_data->host);
                }

                /* destroy all of the device and target objects */
                for (i = 0; i < AHD_NUM_TARGETS; i++) {
                        targ = ahd->platform_data->targets[i];
                        if (targ != NULL) {
                                /* Keep target around through the loop. */
                                targ->refcount++;
                                for (j = 0; j < AHD_NUM_LUNS; j++) {

                                        if (targ->devices[j] == NULL)
                                                continue;
                                        dev = targ->devices[j];
                                        ahd_linux_free_device(ahd, dev);
                                }
                                /*
                                 * Forcibly free the target now that
                                 * all devices are gone.
                                 */
                                ahd_linux_free_target(ahd, targ);
                        }
                }

                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);
                }
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0)
                /*
                 * In 2.4 we detach from the scsi midlayer before the PCI
                 * layer invokes our remove callback.  No per-instance
                 * detach is provided, so we must reach inside the PCI
                 * subsystem's internals and detach our driver manually.
                 */
                if (ahd->dev_softc != NULL)
                        ahd->dev_softc->driver = NULL;
#endif
                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 ahd_linux_device *dev;
        int was_queuing;
        int now_queuing;

        dev = ahd_linux_get_device(ahd, devinfo->channel - 'A',
                                   devinfo->target,
                                   devinfo->lun, /*alloc*/FALSE);
        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;
        }
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
        if (dev->scsi_device != NULL) {
                switch ((dev->flags & (AHD_DEV_Q_BASIC|AHD_DEV_Q_TAGGED))) {
                case AHD_DEV_Q_BASIC:
                        scsi_adjust_queue_depth(dev->scsi_device,
                                                MSG_SIMPLE_TASK,
                                                dev->openings + dev->active);
                        break;
                case AHD_DEV_Q_TAGGED:
                        scsi_adjust_queue_depth(dev->scsi_device,
                                                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(dev->scsi_device,
                                                /*NON-TAGGED*/0,
                                                /*queue depth*/2);
                        break;
                }
        }
#endif
}

int
ahd_platform_abort_scbs(struct ahd_softc *ahd, int target, char channel,
                        int lun, u_int tag, role_t role, uint32_t status)
{
        int targ;
        int maxtarg;
        int maxlun;
        int clun;
        int count;

        if (tag != SCB_LIST_NULL)
                return (0);

        targ = 0;
        if (target != CAM_TARGET_WILDCARD) {
                targ = target;
                maxtarg = targ + 1;
        } else {
                maxtarg = (ahd->features & AHD_WIDE) ? 16 : 8;
        }
        clun = 0;
        if (lun != CAM_LUN_WILDCARD) {
                clun = lun;
                maxlun = clun + 1;
        } else {
                maxlun = AHD_NUM_LUNS;
        }

        count = 0;
        for (; targ < maxtarg; targ++) {

                for (; clun < maxlun; clun++) {
                        struct ahd_linux_device *dev;
                        struct ahd_busyq *busyq;
                        struct ahd_cmd *acmd;

                        dev = ahd_linux_get_device(ahd, /*chan*/0, targ,
                                                   clun, /*alloc*/FALSE);
                        if (dev == NULL)
                                continue;

                        busyq = &dev->busyq;
                        while ((acmd = TAILQ_FIRST(busyq)) != NULL) {
                                Scsi_Cmnd *cmd;

                                cmd = &acmd_scsi_cmd(acmd);
                                TAILQ_REMOVE(busyq, acmd,
                                             acmd_links.tqe);
                                count++;
                                cmd->result = status << 16;
                                ahd_linux_queue_cmd_complete(ahd, cmd);
                        }
                }
        }

        return (count);
}

static void
ahd_linux_thread_run_complete_queue(struct ahd_softc *ahd)
{
        u_long flags;

        ahd_lock(ahd, &flags);
        del_timer(&ahd->platform_data->completeq_timer);
        ahd->platform_data->flags &= ~AHD_RUN_CMPLT_Q_TIMER;
        ahd_linux_run_complete_queue(ahd);
        ahd_unlock(ahd, &flags);
}

static void
ahd_linux_start_dv(struct ahd_softc *ahd)
{

        /*
         * Freeze the simq and signal ahd_linux_queue to not let any
         * more commands through
         */
        if ((ahd->platform_data->flags & AHD_DV_ACTIVE) == 0) {
#ifdef AHD_DEBUG
                if (ahd_debug & AHD_SHOW_DV)
                        printf("%s: Starting DV\n", ahd_name(ahd));
#endif

                ahd->platform_data->flags |= AHD_DV_ACTIVE;
                ahd_freeze_simq(ahd);

                /* Wake up the DV kthread */
                up(&ahd->platform_data->dv_sem);
        }
}

static int
ahd_linux_dv_thread(void *data)
{
        struct  ahd_softc *ahd;
        int     target;
        u_long  s;

        ahd = (struct ahd_softc *)data;

#ifdef AHD_DEBUG
        if (ahd_debug & AHD_SHOW_DV)
                printf("In DV Thread\n");
#endif

        /*
         * Complete thread creation.
         */
        lock_kernel();
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,60)
        /*
         * Don't care about any signals.
         */
        siginitsetinv(&current->blocked, 0);

        daemonize();
        sprintf(current->comm, "ahd_dv_%d", ahd->unit);
#else
        daemonize("ahd_dv_%d", ahd->unit);
        current->flags |= PF_FREEZE;
#endif
        unlock_kernel();

        while (1) {
                /*
                 * Use down_interruptible() rather than down() to
                 * avoid inclusion in the load average.
                 */
                down_interruptible(&ahd->platform_data->dv_sem);

                /* Check to see if we've been signaled to exit */
                ahd_lock(ahd, &s);
                if ((ahd->platform_data->flags & AHD_DV_SHUTDOWN) != 0) {
                        ahd_unlock(ahd, &s);
                        break;
                }
                ahd_unlock(ahd, &s);

#ifdef AHD_DEBUG
                if (ahd_debug & AHD_SHOW_DV)
                        printf("%s: Beginning Domain Validation\n",
                               ahd_name(ahd));
#endif

                /*
                 * Wait for any pending commands to drain before proceeding.
                 */
                ahd_lock(ahd, &s);
                while (LIST_FIRST(&ahd->pending_scbs) != NULL) {
                        ahd->platform_data->flags |= AHD_DV_WAIT_SIMQ_EMPTY;
                        ahd_unlock(ahd, &s);
                        down_interruptible(&ahd->platform_data->dv_sem);
                        ahd_lock(ahd, &s);
                }

                /*
                 * Wait for the SIMQ to be released so that DV is the
                 * only reason the queue is frozen.
                 */
                while (AHD_DV_SIMQ_FROZEN(ahd) == 0) {
                        ahd->platform_data->flags |= AHD_DV_WAIT_SIMQ_RELEASE;
                        ahd_unlock(ahd, &s);
                        down_interruptible(&ahd->platform_data->dv_sem);
                        ahd_lock(ahd, &s);
                }
                ahd_unlock(ahd, &s);

                for (target = 0; target < AHD_NUM_TARGETS; target++)
                        ahd_linux_dv_target(ahd, target);

                ahd_lock(ahd, &s);
                ahd->platform_data->flags &= ~AHD_DV_ACTIVE;
                ahd_unlock(ahd, &s);

                /*
                 * Release the SIMQ so that normal commands are
                 * allowed to continue on the bus.
                 */
                ahd_release_simq(ahd);
        }
        up(&ahd->platform_data->eh_sem);
        return (0);
}

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

        ahd_lock(ahd, &s);
        if (ahd->platform_data->dv_pid != 0) {
                ahd->platform_data->flags |= AHD_DV_SHUTDOWN;
                ahd_unlock(ahd, &s);
                up(&ahd->platform_data->dv_sem);

                /*
                 * Use the eh_sem as an indicator that the
                 * dv thread is exiting.  Note that the dv
                 * thread must still return after performing
                 * the up on our semaphore before it has
                 * completely exited this module.  Unfortunately,
                 * there seems to be no easy way to wait for the
                 * exit of a thread for which you are not the
                 * parent (dv threads are parented by init).
                 * Cross your fingers...
                 */
                down(&ahd->platform_data->eh_sem);

                /*
                 * Mark the dv thread as already dead.  This
                 * avoids attempting to kill it a second time.
                 * This is necessary because we must kill the
                 * DV thread before calling ahd_free() in the
                 * module shutdown case to avoid bogus locking
                 * in the SCSI mid-layer, but we ahd_free() is
                 * called without killing the DV thread in the
                 * instance detach case, so ahd_platform_free()
                 * calls us again to verify that the DV thread
                 * is dead.
                 */
                ahd->platform_data->dv_pid = 0;
        } else {
                ahd_unlock(ahd, &s);
        }
}

#define AHD_LINUX_DV_INQ_SHORT_LEN      36
#define AHD_LINUX_DV_INQ_LEN            256
#define AHD_LINUX_DV_TIMEOUT            (HZ / 4)

#define AHD_SET_DV_STATE(ahd, targ, newstate) \
        ahd_set_dv_state(ahd, targ, newstate, __LINE__)

static __inline void
ahd_set_dv_state(struct ahd_softc *ahd, struct ahd_linux_target *targ,
                 ahd_dv_state newstate, u_int line)
{
        ahd_dv_state oldstate;

        oldstate = targ->dv_state;
#ifdef AHD_DEBUG
        if (ahd_debug & AHD_SHOW_DV)
                printf("%s:%d: Going from state %d to state %d\n",
                       ahd_name(ahd), line, oldstate, newstate);
#endif

        if (oldstate == newstate)
                targ->dv_state_retry++;
        else
                targ->dv_state_retry = 0;
        targ->dv_state = newstate;
}

static void
ahd_linux_dv_target(struct ahd_softc *ahd, u_int target_offset)
{
        struct   ahd_devinfo devinfo;
        struct   ahd_linux_target *targ;
        struct   scsi_cmnd *cmd;
        struct   scsi_device *scsi_dev;
        struct   scsi_sense_data *sense;
        uint8_t *buffer;
        u_long   s;
        u_int    timeout;
        int      echo_size;

        sense = NULL;
        buffer = NULL;
        echo_size = 0;
        ahd_lock(ahd, &s);
        targ = ahd->platform_data->targets[target_offset];
        if (targ == NULL || (targ->flags & AHD_DV_REQUIRED) == 0) {
                ahd_unlock(ahd, &s);
                return;
        }
        ahd_compile_devinfo(&devinfo, ahd->our_id, targ->target, /*lun*/0,
                            targ->channel + 'A', ROLE_INITIATOR);
#ifdef AHD_DEBUG
        if (ahd_debug & AHD_SHOW_DV) {
                ahd_print_devinfo(ahd, &devinfo);
                printf("Performing DV\n");
        }
#endif

        ahd_unlock(ahd, &s);

        cmd = malloc(sizeof(struct scsi_cmnd), M_DEVBUF, M_WAITOK);
        scsi_dev = malloc(sizeof(struct scsi_device), M_DEVBUF, M_WAITOK);
        scsi_dev->host = ahd->platform_data->host;
        scsi_dev->id = devinfo.target;
        scsi_dev->lun = devinfo.lun;
        scsi_dev->channel = devinfo.channel - 'A';
        ahd->platform_data->dv_scsi_dev = scsi_dev;

        AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_INQ_SHORT_ASYNC);

        while (targ->dv_state != AHD_DV_STATE_EXIT) {
                timeout = AHD_LINUX_DV_TIMEOUT;
                switch (targ->dv_state) {
                case AHD_DV_STATE_INQ_SHORT_ASYNC:
                case AHD_DV_STATE_INQ_ASYNC:
                case AHD_DV_STATE_INQ_ASYNC_VERIFY:
                        /*
                         * Set things to async narrow to reduce the
                         * chance that the INQ will fail.
                         */
                        ahd_lock(ahd, &s);
                        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, &s);
                        timeout = 10 * HZ;
                        targ->flags &= ~AHD_INQ_VALID;
                        /* FALLTHROUGH */
                case AHD_DV_STATE_INQ_VERIFY:
                {
                        u_int inq_len;

                        if (targ->dv_state == AHD_DV_STATE_INQ_SHORT_ASYNC)
                                inq_len = AHD_LINUX_DV_INQ_SHORT_LEN;
                        else
                                inq_len = targ->inq_data->additional_length + 5;
                        ahd_linux_dv_inq(ahd, cmd, &devinfo, targ, inq_len);
                        break;
                }
                case AHD_DV_STATE_TUR:
                case AHD_DV_STATE_BUSY:
                        timeout = 5 * HZ;
                        ahd_linux_dv_tur(ahd, cmd, &devinfo);
                        break;
                case AHD_DV_STATE_REBD:
                        ahd_linux_dv_rebd(ahd, cmd, &devinfo, targ);
                        break;
                case AHD_DV_STATE_WEB:
                        ahd_linux_dv_web(ahd, cmd, &devinfo, targ);
                        break;

                case AHD_DV_STATE_REB:
                        ahd_linux_dv_reb(ahd, cmd, &devinfo, targ);
                        break;

                case AHD_DV_STATE_SU:
                        ahd_linux_dv_su(ahd, cmd, &devinfo, targ);
                        timeout = 50 * HZ;
                        break;

                default:
                        ahd_print_devinfo(ahd, &devinfo);
                        printf("Unknown DV state %d\n", targ->dv_state);
                        goto out;
                }

                /* Queue the command and wait for it to complete */
                /* Abuse eh_timeout in the scsi_cmnd struct for our purposes */
                init_timer(&cmd->eh_timeout);
#ifdef AHD_DEBUG
                if ((ahd_debug & AHD_SHOW_MESSAGES) != 0)
                        /*
                         * All of the printfs during negotiation
                         * really slow down the negotiation.
                         * Add a bit of time just to be safe.
                         */
                        timeout += HZ;
#endif
                scsi_add_timer(cmd, timeout, ahd_linux_dv_timeout);
                /*
                 * In 2.5.X, it is assumed that all calls from the
                 * "midlayer" (which we are emulating) will have the
                 * ahd host lock held.  For other kernels, the
                 * io_request_lock must be held.
                 */
#if AHD_SCSI_HAS_HOST_LOCK != 0
                ahd_lock(ahd, &s);
#else
                spin_lock_irqsave(&io_request_lock, s);
#endif
                ahd_linux_queue(cmd, ahd_linux_dv_complete);
#if AHD_SCSI_HAS_HOST_LOCK != 0
                ahd_unlock(ahd, &s);
#else
                spin_unlock_irqrestore(&io_request_lock, s);
#endif
                down_interruptible(&ahd->platform_data->dv_cmd_sem);
                /*
                 * Wait for the SIMQ to be released so that DV is the
                 * only reason the queue is frozen.
                 */
                ahd_lock(ahd, &s);
                while (AHD_DV_SIMQ_FROZEN(ahd) == 0) {
                        ahd->platform_data->flags |= AHD_DV_WAIT_SIMQ_RELEASE;
                        ahd_unlock(ahd, &s);
                        down_interruptible(&ahd->platform_data->dv_sem);
                        ahd_lock(ahd, &s);
                }
                ahd_unlock(ahd, &s);

                ahd_linux_dv_transition(ahd, cmd, &devinfo, targ);
        }

out:
        if ((targ->flags & AHD_INQ_VALID) != 0
         && ahd_linux_get_device(ahd, devinfo.channel - 'A',
                                 devinfo.target, devinfo.lun,
                                 /*alloc*/FALSE) == NULL) {
                /*
                 * The DV state machine failed to configure this device.  
                 * This is normal if DV is disabled.  Since we have inquiry
                 * data, filter it and use the "optimistic" negotiation
                 * parameters found in the inquiry string.
                 */
                ahd_linux_filter_inquiry(ahd, &devinfo);
                if ((targ->flags & (AHD_BASIC_DV|AHD_ENHANCED_DV)) != 0) {
                        ahd_print_devinfo(ahd, &devinfo);
                        printf("DV failed to configure device.  "
                               "Please file a bug report against "
                               "this driver.\n");
                }
        }

        if (cmd != NULL)
                free(cmd, M_DEVBUF);

        if (ahd->platform_data->dv_scsi_dev != NULL) {
                free(ahd->platform_data->dv_scsi_dev, M_DEVBUF);
                ahd->platform_data->dv_scsi_dev = NULL;
        }

        ahd_lock(ahd, &s);
        if (targ->dv_buffer != NULL) {
                free(targ->dv_buffer, M_DEVBUF);
                targ->dv_buffer = NULL;
        }
        if (targ->dv_buffer1 != NULL) {
                free(targ->dv_buffer1, M_DEVBUF);
                targ->dv_buffer1 = NULL;
        }
        targ->flags &= ~AHD_DV_REQUIRED;
        if (targ->refcount == 0)
                ahd_linux_free_target(ahd, targ);
        ahd_unlock(ahd, &s);
}

static __inline int
ahd_linux_dv_fallback(struct ahd_softc *ahd, struct ahd_devinfo *devinfo)
{
        u_long s;
        int retval;

        ahd_lock(ahd, &s);
        retval = ahd_linux_fallback(ahd, devinfo);
        ahd_unlock(ahd, &s);

        return (retval);
}

static void
ahd_linux_dv_transition(struct ahd_softc *ahd, struct scsi_cmnd *cmd,
                        struct ahd_devinfo *devinfo,
                        struct ahd_linux_target *targ)
{
        u_int32_t status;

        status = aic_error_action(cmd, targ->inq_data,
                                  ahd_cmd_get_transaction_status(cmd),
                                  ahd_cmd_get_scsi_status(cmd));

        
#ifdef AHD_DEBUG
        if (ahd_debug & AHD_SHOW_DV) {
                ahd_print_devinfo(ahd, devinfo);
                printf("Entering ahd_linux_dv_transition, state= %d, "
                       "status= 0x%x, cmd->result= 0x%x\n", targ->dv_state,
                       status, cmd->result);
        }
#endif

        switch (targ->dv_state) {
        case AHD_DV_STATE_INQ_SHORT_ASYNC:
        case AHD_DV_STATE_INQ_ASYNC:
                switch (status & SS_MASK) {
                case SS_NOP:
                {
                        AHD_SET_DV_STATE(ahd, targ, targ->dv_state+1);
                        break;
                }
                case SS_INQ_REFRESH:
                        AHD_SET_DV_STATE(ahd, targ,
                                         AHD_DV_STATE_INQ_SHORT_ASYNC);
                        break;
                case SS_TUR:
                case SS_RETRY:
                        AHD_SET_DV_STATE(ahd, targ, targ->dv_state);
                        if (ahd_cmd_get_transaction_status(cmd)
                         == CAM_REQUEUE_REQ)
                                targ->dv_state_retry--;
                        if ((status & SS_ERRMASK) == EBUSY)
                                AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_BUSY);
                        if (targ->dv_state_retry < 10)
                                break;
                        /* FALLTHROUGH */
                default:
                        AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_EXIT);
#ifdef AHD_DEBUG
                        if (ahd_debug & AHD_SHOW_DV) {
                                ahd_print_devinfo(ahd, devinfo);
                                printf("Failed DV inquiry, skipping\n");
                        }
#endif
                        break;
                }
                break;
        case AHD_DV_STATE_INQ_ASYNC_VERIFY:
                switch (status & SS_MASK) {
                case SS_NOP:
                {
                        u_int xportflags;
                        u_int spi3data;

                        if (memcmp(targ->inq_data, targ->dv_buffer,
                                   AHD_LINUX_DV_INQ_LEN) != 0) {
                                /*
                                 * Inquiry data must have changed.
                                 * Try from the top again.
                                 */
                                AHD_SET_DV_STATE(ahd, targ,
                                                 AHD_DV_STATE_INQ_SHORT_ASYNC);
                                break;
                        }

                        AHD_SET_DV_STATE(ahd, targ, targ->dv_state+1);
                        targ->flags |= AHD_INQ_VALID;
                        if (ahd_linux_user_dv_setting(ahd) == 0)
                                break;

                        xportflags = targ->inq_data->flags;
                        if ((xportflags & (SID_Sync|SID_WBus16)) == 0)
                                break;

                        spi3data = targ->inq_data->spi3data;
                        switch (spi3data & SID_SPI_CLOCK_DT_ST) {
                        default:
                        case SID_SPI_CLOCK_ST:
                                /* Assume only basic DV is supported. */
                                targ->flags |= AHD_BASIC_DV;
                                break;
                        case SID_SPI_CLOCK_DT:
                        case SID_SPI_CLOCK_DT_ST:
                                targ->flags |= AHD_ENHANCED_DV;
                                break;
                        }
                        break;
                }
                case SS_INQ_REFRESH:
                        AHD_SET_DV_STATE(ahd, targ,
                                         AHD_DV_STATE_INQ_SHORT_ASYNC);
                        break;
                case SS_TUR:
                case SS_RETRY:
                        AHD_SET_DV_STATE(ahd, targ, targ->dv_state);
                        if (ahd_cmd_get_transaction_status(cmd)
                         == CAM_REQUEUE_REQ)
                                targ->dv_state_retry--;

                        if ((status & SS_ERRMASK) == EBUSY)
                                AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_BUSY);
                        if (targ->dv_state_retry < 10)
                                break;
                        /* FALLTHROUGH */
                default:
                        AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_EXIT);
#ifdef AHD_DEBUG
                        if (ahd_debug & AHD_SHOW_DV) {
                                ahd_print_devinfo(ahd, devinfo);
                                printf("Failed DV inquiry, skipping\n");
                        }
#endif
                        break;
                }
                break;
        case AHD_DV_STATE_INQ_VERIFY:
                switch (status & SS_MASK) {
                case SS_NOP:
                {

                        if (memcmp(targ->inq_data, targ->dv_buffer,
                                   AHD_LINUX_DV_INQ_LEN) == 0) {
                                AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_EXIT);
                                break;
                        }

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

                                ahd_print_devinfo(ahd, devinfo);
                                printf("Inquiry buffer mismatch:");
                                for (i = 0; i < AHD_LINUX_DV_INQ_LEN; i++) {
                                        if ((i & 0xF) == 0)
                                                printf("\n        ");
                                        printf("0x%x:0x0%x ",
                                               ((uint8_t *)targ->inq_data)[i], 
                                               targ->dv_buffer[i]);
                                }
                                printf("\n");
                        }
#endif

                        if (ahd_linux_dv_fallback(ahd, devinfo) != 0) {
                                AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_EXIT);
                                break;
                        }
                        /*
                         * Do not count "falling back"
                         * against our retries.
                         */
                        targ->dv_state_retry = 0;
                        AHD_SET_DV_STATE(ahd, targ, targ->dv_state);
                        break;
                }
                case SS_INQ_REFRESH:
                        AHD_SET_DV_STATE(ahd, targ,
                                         AHD_DV_STATE_INQ_SHORT_ASYNC);
                        break;
                case SS_TUR:
                case SS_RETRY:
                        AHD_SET_DV_STATE(ahd, targ, targ->dv_state);
                        if (ahd_cmd_get_transaction_status(cmd)
                         == CAM_REQUEUE_REQ) {
                                targ->dv_state_retry--;
                        } else if ((status & SSQ_FALLBACK) != 0) {
                                if (ahd_linux_dv_fallback(ahd, devinfo) != 0) {
                                        AHD_SET_DV_STATE(ahd, targ,
                                                         AHD_DV_STATE_EXIT);
                                        break;
                                }
                                /*
                                 * Do not count "falling back"
                                 * against our retries.
                                 */
                                targ->dv_state_retry = 0;
                        } else if ((status & SS_ERRMASK) == EBUSY)
                                AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_BUSY);
                        if (targ->dv_state_retry < 10)
                                break;
                        /* FALLTHROUGH */
                default:
                        AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_EXIT);
#ifdef AHD_DEBUG
                        if (ahd_debug & AHD_SHOW_DV) {
                                ahd_print_devinfo(ahd, devinfo);
                                printf("Failed DV inquiry, skipping\n");
                        }
#endif
                        break;
                }
                break;

        case AHD_DV_STATE_TUR:
                switch (status & SS_MASK) {
                case SS_NOP:
                        if ((targ->flags & AHD_BASIC_DV) != 0) {
                                ahd_linux_filter_inquiry(ahd, devinfo);
                                AHD_SET_DV_STATE(ahd, targ,
                                                 AHD_DV_STATE_INQ_VERIFY);
                        } else if ((targ->flags & AHD_ENHANCED_DV) != 0) {
                                AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_REBD);
                        } else {
                                AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_EXIT);
                        }
                        break;
                case SS_RETRY:
                case SS_TUR:
                        if ((status & SS_ERRMASK) == EBUSY) {
                                AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_BUSY);
                                break;
                        }
                        AHD_SET_DV_STATE(ahd, targ, targ->dv_state);
                        if (ahd_cmd_get_transaction_status(cmd)
                         == CAM_REQUEUE_REQ) {
                                targ->dv_state_retry--;
                        } else if ((status & SSQ_FALLBACK) != 0) {
                                if (ahd_linux_dv_fallback(ahd, devinfo) != 0) {
                                        AHD_SET_DV_STATE(ahd, targ,
                                                         AHD_DV_STATE_EXIT);
                                        break;
                                }
                                /*
                                 * Do not count "falling back"
                                 * against our retries.
                                 */
                                targ->dv_state_retry = 0;
                        }
                        if (targ->dv_state_retry >= 10) {
#ifdef AHD_DEBUG
                                if (ahd_debug & AHD_SHOW_DV) {
                                        ahd_print_devinfo(ahd, devinfo);
                                        printf("DV TUR reties exhausted\n");
                                }
#endif
                                AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_EXIT);
                                break;
                        }
                        if (status & SSQ_DELAY)
                                ssleep(1);

                        break;
                case SS_START:
                        AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_SU);
                        break;
                case SS_INQ_REFRESH:
                        AHD_SET_DV_STATE(ahd, targ,
                                         AHD_DV_STATE_INQ_SHORT_ASYNC);
                        break;
                default:
                        AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_EXIT);
                        break;
                }
                break;

        case AHD_DV_STATE_REBD:
                switch (status & SS_MASK) {
                case SS_NOP:
                {
                        uint32_t echo_size;

                        AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_WEB);
                        echo_size = scsi_3btoul(&targ->dv_buffer[1]);
                        echo_size &= 0x1FFF;
#ifdef AHD_DEBUG
                        if (ahd_debug & AHD_SHOW_DV) {
                                ahd_print_devinfo(ahd, devinfo);
                                printf("Echo buffer size= %d\n", echo_size);
                        }
#endif
                        if (echo_size == 0) {
                                AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_EXIT);
                                break;
                        }

                        /* Generate the buffer pattern */
                        targ->dv_echo_size = echo_size;
                        ahd_linux_generate_dv_pattern(targ);
                        /*
                         * Setup initial negotiation values.
                         */
                        ahd_linux_filter_inquiry(ahd, devinfo);
                        break;
                }
                case SS_INQ_REFRESH:
                        AHD_SET_DV_STATE(ahd, targ,
                                         AHD_DV_STATE_INQ_SHORT_ASYNC);
                        break;
                case SS_RETRY:
                        AHD_SET_DV_STATE(ahd, targ, targ->dv_state);
                        if (ahd_cmd_get_transaction_status(cmd)
                         == CAM_REQUEUE_REQ)
                                targ->dv_state_retry--;
                        if (targ->dv_state_retry <= 10)
                                break;
#ifdef AHD_DEBUG
                        if (ahd_debug & AHD_SHOW_DV) {
                                ahd_print_devinfo(ahd, devinfo);
                                printf("DV REBD reties exhausted\n");
                        }
#endif
                        /* FALLTHROUGH */
                case SS_FATAL:
                default:
                        /*
                         * Setup initial negotiation values
                         * and try level 1 DV.
                         */
                        ahd_linux_filter_inquiry(ahd, devinfo);
                        AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_INQ_VERIFY);
                        targ->dv_echo_size = 0;
                        break;
                }
                break;

        case AHD_DV_STATE_WEB:
                switch (status & SS_MASK) {
                case SS_NOP:
                        AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_REB);
                        break;
                case SS_INQ_REFRESH:
                        AHD_SET_DV_STATE(ahd, targ,
                                         AHD_DV_STATE_INQ_SHORT_ASYNC);
                        break;
                case SS_RETRY:
                        AHD_SET_DV_STATE(ahd, targ, targ->dv_state);
                        if (ahd_cmd_get_transaction_status(cmd)
                         == CAM_REQUEUE_REQ) {
                                targ->dv_state_retry--;
                        } else if ((status & SSQ_FALLBACK) != 0) {
                                if (ahd_linux_dv_fallback(ahd, devinfo) != 0) {
                                        AHD_SET_DV_STATE(ahd, targ,
                                                         AHD_DV_STATE_EXIT);
                                        break;
                                }
                                /*
                                 * Do not count "falling back"
                                 * against our retries.
                                 */
                                targ->dv_state_retry = 0;
                        }
                        if (targ->dv_state_retry <= 10)
                                break;
                        /* FALLTHROUGH */
#ifdef AHD_DEBUG
                        if (ahd_debug & AHD_SHOW_DV) {
                                ahd_print_devinfo(ahd, devinfo);
                                printf("DV WEB reties exhausted\n");
                        }
#endif
                default:
                        AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_EXIT);
                        break;
                }
                break;

        case AHD_DV_STATE_REB:
                switch (status & SS_MASK) {
                case SS_NOP:
                        if (memcmp(targ->dv_buffer, targ->dv_buffer1,
                                   targ->dv_echo_size) != 0) {
                                if (ahd_linux_dv_fallback(ahd, devinfo) != 0)
                                        AHD_SET_DV_STATE(ahd, targ,
                                                         AHD_DV_STATE_EXIT);
                                else
                                        AHD_SET_DV_STATE(ahd, targ,
                                                         AHD_DV_STATE_WEB);
                                break;
                        }
                        
                        if (targ->dv_buffer != NULL) {
                                free(targ->dv_buffer, M_DEVBUF);
                                targ->dv_buffer = NULL;
                        }
                        if (targ->dv_buffer1 != NULL) {
                                free(targ->dv_buffer1, M_DEVBUF);
                                targ->dv_buffer1 = NULL;
                        }
                        AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_EXIT);
                        break;
                case SS_INQ_REFRESH:
                        AHD_SET_DV_STATE(ahd, targ,
                                         AHD_DV_STATE_INQ_SHORT_ASYNC);
                        break;
                case SS_RETRY:
                        AHD_SET_DV_STATE(ahd, targ, targ->dv_state);
                        if (ahd_cmd_get_transaction_status(cmd)
                         == CAM_REQUEUE_REQ) {
                                targ->dv_state_retry--;
                        } else if ((status & SSQ_FALLBACK) != 0) {
                                if (ahd_linux_dv_fallback(ahd, devinfo) != 0) {
                                        AHD_SET_DV_STATE(ahd, targ,
                                                         AHD_DV_STATE_EXIT);
                                        break;
                                }
                                AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_WEB);
                        }
                        if (targ->dv_state_retry <= 10) {
                                if ((status & (SSQ_DELAY_RANDOM|SSQ_DELAY))!= 0)
                                        msleep(ahd->our_id*1000/10);
                                break;
                        }
#ifdef AHD_DEBUG
                        if (ahd_debug & AHD_SHOW_DV) {
                                ahd_print_devinfo(ahd, devinfo);
                                printf("DV REB reties exhausted\n");
                        }
#endif
                        /* FALLTHROUGH */
                default:
                        AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_EXIT);
                        break;
                }
                break;

        case AHD_DV_STATE_SU:
                switch (status & SS_MASK) {
                case SS_NOP:
                case SS_INQ_REFRESH:
                        AHD_SET_DV_STATE(ahd, targ,
                                         AHD_DV_STATE_INQ_SHORT_ASYNC);
                        break;
                default:
                        AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_EXIT);
                        break;
                }
                break;

        case AHD_DV_STATE_BUSY:
                switch (status & SS_MASK) {
                case SS_NOP:
                case SS_INQ_REFRESH:
                        AHD_SET_DV_STATE(ahd, targ,
                                         AHD_DV_STATE_INQ_SHORT_ASYNC);
                        break;
                case SS_TUR:
                case SS_RETRY:
                        AHD_SET_DV_STATE(ahd, targ, targ->dv_state);
                        if (ahd_cmd_get_transaction_status(cmd)
                         == CAM_REQUEUE_REQ) {
                                targ->dv_state_retry--;
                        } else if (targ->dv_state_retry < 60) {
                                if ((status & SSQ_DELAY) != 0)
                                        ssleep(1);
                        } else {
#ifdef AHD_DEBUG
                                if (ahd_debug & AHD_SHOW_DV) {
                                        ahd_print_devinfo(ahd, devinfo);
                                        printf("DV BUSY reties exhausted\n");
                                }
#endif
                                AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_EXIT);
                        }
                        break;
                default:
                        AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_EXIT);
                        break;
                }
                break;

        default:
                printf("%s: Invalid DV completion state %d\n", ahd_name(ahd),
                       targ->dv_state);
                AHD_SET_DV_STATE(ahd, targ, AHD_DV_STATE_EXIT);
                break;
        }
}

static void
ahd_linux_dv_fill_cmd(struct ahd_softc *ahd, struct scsi_cmnd *cmd,
                      struct ahd_devinfo *devinfo)
{
        memset(cmd, 0, sizeof(struct scsi_cmnd));
        cmd->device = ahd->platform_data->dv_scsi_dev;
        cmd->scsi_done = ahd_linux_dv_complete;
}

/*
 * Synthesize an inquiry command.  On the return trip, it'll be
 * sniffed and the device transfer settings set for us.
 */
static void
ahd_linux_dv_inq(struct ahd_softc *ahd, struct scsi_cmnd *cmd,
                 struct ahd_devinfo *devinfo, struct ahd_linux_target *targ,
                 u_int request_length)
{

#ifdef AHD_DEBUG
        if (ahd_debug & AHD_SHOW_DV) {
                ahd_print_devinfo(ahd, devinfo);
                printf("Sending INQ\n");
        }
#endif
        if (targ->inq_data == NULL)
                targ->inq_data = malloc(AHD_LINUX_DV_INQ_LEN,
                                        M_DEVBUF, M_WAITOK);
        if (targ->dv_state > AHD_DV_STATE_INQ_ASYNC) {
                if (targ->dv_buffer != NULL)
                        free(targ->dv_buffer, M_DEVBUF);
                targ->dv_buffer = malloc(AHD_LINUX_DV_INQ_LEN,
                                         M_DEVBUF, M_WAITOK);
        }

        ahd_linux_dv_fill_cmd(ahd, cmd, devinfo);
        cmd->sc_data_direction = DMA_FROM_DEVICE;
        cmd->cmd_len = 6;
        cmd->cmnd[0] = INQUIRY;
        cmd->cmnd[4] = request_length;
        cmd->request_bufflen = request_length;
        if (targ->dv_state > AHD_DV_STATE_INQ_ASYNC)
                cmd->request_buffer = targ->dv_buffer;
        else
                cmd->request_buffer = targ->inq_data;
        memset(cmd->request_buffer, 0, AHD_LINUX_DV_INQ_LEN);
}

static void
ahd_linux_dv_tur(struct ahd_softc *ahd, struct scsi_cmnd *cmd,
                 struct ahd_devinfo *devinfo)
{

#ifdef AHD_DEBUG
        if (ahd_debug & AHD_SHOW_DV) {
                ahd_print_devinfo(ahd, devinfo);
                printf("Sending TUR\n");
        }
#endif
        /* Do a TUR to clear out any non-fatal transitional state */
        ahd_linux_dv_fill_cmd(ahd, cmd, devinfo);
        cmd->sc_data_direction = DMA_NONE;
        cmd->cmd_len = 6;
        cmd->cmnd[0] = TEST_UNIT_READY;
}

#define AHD_REBD_LEN 4

static void
ahd_linux_dv_rebd(struct ahd_softc *ahd, struct scsi_cmnd *cmd,
                 struct ahd_devinfo *devinfo, struct ahd_linux_target *targ)
{

#ifdef AHD_DEBUG
        if (ahd_debug & AHD_SHOW_DV) {
                ahd_print_devinfo(ahd, devinfo);
                printf("Sending REBD\n");
        }
#endif
        if (targ->dv_buffer != NULL)
                free(targ->dv_buffer, M_DEVBUF);
        targ->dv_buffer = malloc(AHD_REBD_LEN, M_DEVBUF, M_WAITOK);
        ahd_linux_dv_fill_cmd(ahd, cmd, devinfo);
        cmd->sc_data_direction = DMA_FROM_DEVICE;
        cmd->cmd_len = 10;
        cmd->cmnd[0] = READ_BUFFER;
        cmd->cmnd[1] = 0x0b;
        scsi_ulto3b(AHD_REBD_LEN, &cmd->cmnd[6]);
        cmd->request_bufflen = AHD_REBD_LEN;
        cmd->underflow = cmd->request_bufflen;
        cmd->request_buffer = targ->dv_buffer;
}

static void
ahd_linux_dv_web(struct ahd_softc *ahd, struct scsi_cmnd *cmd,
                 struct ahd_devinfo *devinfo, struct ahd_linux_target *targ)
{

#ifdef AHD_DEBUG
        if (ahd_debug & AHD_SHOW_DV) {
                ahd_print_devinfo(ahd, devinfo);
                printf("Sending WEB\n");
        }
#endif
        ahd_linux_dv_fill_cmd(ahd, cmd, devinfo);
        cmd->sc_data_direction = DMA_TO_DEVICE;
        cmd->cmd_len = 10;
        cmd->cmnd[0] = WRITE_BUFFER;
        cmd->cmnd[1] = 0x0a;
        scsi_ulto3b(targ->dv_echo_size, &cmd->cmnd[6]);
        cmd->request_bufflen = targ->dv_echo_size;
        cmd->underflow = cmd->request_bufflen;
        cmd->request_buffer = targ->dv_buffer;
}

static void
ahd_linux_dv_reb(struct ahd_softc *ahd, struct scsi_cmnd *cmd,
                 struct ahd_devinfo *devinfo, struct ahd_linux_target *targ)
{

#ifdef AHD_DEBUG
        if (ahd_debug & AHD_SHOW_DV) {
                ahd_print_devinfo(ahd, devinfo);
                printf("Sending REB\n");
        }
#endif
        ahd_linux_dv_fill_cmd(ahd, cmd, devinfo);
        cmd->sc_data_direction = DMA_FROM_DEVICE;
        cmd->cmd_len = 10;
        cmd->cmnd[0] = READ_BUFFER;
        cmd->cmnd[1] = 0x0a;
        scsi_ulto3b(targ->dv_echo_size, &cmd->cmnd[6]);
        cmd->request_bufflen = targ->dv_echo_size;
        cmd->underflow = cmd->request_bufflen;
        cmd->request_buffer = targ->dv_buffer1;
}

static void
ahd_linux_dv_su(struct ahd_softc *ahd, struct scsi_cmnd *cmd,
                struct ahd_devinfo *devinfo,
                struct ahd_linux_target *targ)
{
        u_int le;

        le = SID_IS_REMOVABLE(targ->inq_data) ? SSS_LOEJ : 0;

#ifdef AHD_DEBUG
        if (ahd_debug & AHD_SHOW_DV) {
                ahd_print_devinfo(ahd, devinfo);
                printf("Sending SU\n");
        }
#endif
        ahd_linux_dv_fill_cmd(ahd, cmd, devinfo);
        cmd->sc_data_direction = DMA_NONE;
        cmd->cmd_len = 6;
        cmd->cmnd[0] = START_STOP_UNIT;
        cmd->cmnd[4] = le | SSS_START;
}

static int
ahd_linux_fallback(struct ahd_softc *ahd, struct ahd_devinfo *devinfo)
{
        struct  ahd_linux_target *targ;
        struct  ahd_initiator_tinfo *tinfo;
        struct  ahd_transinfo *goal;
        struct  ahd_tmode_tstate *tstate;
        u_int   width;
        u_int   period;
        u_int   offset;
        u_int   ppr_options;
        u_int   cur_speed;
        u_int   wide_speed;
        u_int   narrow_speed;
        u_int   fallback_speed;

#ifdef AHD_DEBUG
        if (ahd_debug & AHD_SHOW_DV) {
                ahd_print_devinfo(ahd, devinfo);
                printf("Trying to fallback\n");
        }
#endif
        targ = ahd->platform_data->targets[devinfo->target_offset];
        tinfo = ahd_fetch_transinfo(ahd, devinfo->channel,
                                    devinfo->our_scsiid,
                                    devinfo->target, &tstate);
        goal = &tinfo->goal;
        width = goal->width;
        period = goal->period;
        offset = goal->offset;
        ppr_options = goal->ppr_options;
        if (offset == 0)
                period = AHD_ASYNC_XFER_PERIOD;
        if (targ->dv_next_narrow_period == 0)
                targ->dv_next_narrow_period = MAX(period, AHD_SYNCRATE_ULTRA2);
        if (targ->dv_next_wide_period == 0)
                targ->dv_next_wide_period = period;
        if (targ->dv_max_width == 0)
                targ->dv_max_width = width;
        if (targ->dv_max_ppr_options == 0)
                targ->dv_max_ppr_options = ppr_options;
        if (targ->dv_last_ppr_options == 0)
                targ->dv_last_ppr_options = ppr_options;

        cur_speed = aic_calc_speed(width, period, offset, AHD_SYNCRATE_MIN);
        wide_speed = aic_calc_speed(MSG_EXT_WDTR_BUS_16_BIT,
                                          targ->dv_next_wide_period,
                                          MAX_OFFSET, AHD_SYNCRATE_MIN);
        narrow_speed = aic_calc_speed(MSG_EXT_WDTR_BUS_8_BIT,
                                            targ->dv_next_narrow_period,
                                            MAX_OFFSET, AHD_SYNCRATE_MIN);
        fallback_speed = aic_calc_speed(width, period+1, offset,
                                              AHD_SYNCRATE_MIN);
#ifdef AHD_DEBUG
        if (ahd_debug & AHD_SHOW_DV) {
                printf("cur_speed= %d, wide_speed= %d, narrow_speed= %d, "
                       "fallback_speed= %d\n", cur_speed, wide_speed,
                       narrow_speed, fallback_speed);
        }
#endif

        if (cur_speed > 160000) {
                /*
                 * Paced/DT/IU_REQ only transfer speeds.  All we
                 * can do is fallback in terms of syncrate.
                 */
                period++;
        } else if (cur_speed > 80000) {
                if ((ppr_options & MSG_EXT_PPR_IU_REQ) != 0) {
                        /*
                         * Try without IU_REQ as it may be confusing
                         * an expander.
                         */
                        ppr_options &= ~MSG_EXT_PPR_IU_REQ;
                } else {
                        /*
                         * Paced/DT only transfer speeds.  All we
                         * can do is fallback in terms of syncrate.
                         */
                        period++;
                        ppr_options = targ->dv_max_ppr_options;
                }
        } else if (cur_speed > 3300) {

                /*
                 * In this range we the following
                 * options ordered from highest to
                 * lowest desireability:
                 *
                 * o Wide/DT
                 * o Wide/non-DT
                 * o Narrow at a potentally higher sync rate.
                 *
                 * All modes are tested with and without IU_REQ
                 * set since using IUs may confuse an expander.
                 */
                if ((ppr_options & MSG_EXT_PPR_IU_REQ) != 0) {

                        ppr_options &= ~MSG_EXT_PPR_IU_REQ;
                } else if ((ppr_options & MSG_EXT_PPR_DT_REQ) != 0) {
                        /*
                         * Try going non-DT.
                         */
                        ppr_options = targ->dv_max_ppr_options;
                        ppr_options &= ~MSG_EXT_PPR_DT_REQ;
                } else if (targ->dv_last_ppr_options != 0) {
                        /*
                         * Try without QAS or any other PPR options.
                         * We may need a non-PPR message to work with
                         * an expander.  We look at the "last PPR options"
                         * so we will perform this fallback even if the
                         * target responded to our PPR negotiation with
                         * no option bits set.
                         */
                        ppr_options = 0;
                } else if (width == MSG_EXT_WDTR_BUS_16_BIT) {
                        /*
                         * If the next narrow speed is greater than
                         * the next wide speed, fallback to narrow.
                         * Otherwise fallback to the next DT/Wide setting.
                         * The narrow async speed will always be smaller
                         * than the wide async speed, so handle this case
                         * specifically.
                         */
                        ppr_options = targ->dv_max_ppr_options;
                        if (narrow_speed > fallback_speed
                         || period >= AHD_ASYNC_XFER_PERIOD) {
                                targ->dv_next_wide_period = period+1;
                                width = MSG_EXT_WDTR_BUS_8_BIT;
                                period = targ->dv_next_narrow_period;
                        } else {
                                period++;
                        }
                } else if ((ahd->features & AHD_WIDE) != 0
                        && targ->dv_max_width != 0
                        && wide_speed >= fallback_speed
                        && (targ->dv_next_wide_period <= AHD_ASYNC_XFER_PERIOD
                         || period >= AHD_ASYNC_XFER_PERIOD)) {

                        /*
                         * We are narrow.  Try falling back
                         * to the next wide speed with 
                         * all supported ppr options set.
                         */
                        targ->dv_next_narrow_period = period+1;
                        width = MSG_EXT_WDTR_BUS_16_BIT;
                        period = targ->dv_next_wide_period;
                        ppr_options = targ->dv_max_ppr_options;
                } else {
                        /* Only narrow fallback is allowed. */
                        period++;
                        ppr_options = targ->dv_max_ppr_options;
                }
        } else {
                return (-1);
        }
        offset = MAX_OFFSET;
        ahd_find_syncrate(ahd, &period, &ppr_options, AHD_SYNCRATE_PACED);
        ahd_set_width(ahd, devinfo, width, AHD_TRANS_GOAL, FALSE);
        if (period == 0) {
                period = 0;
                offset = 0;
                ppr_options = 0;
                if (width == MSG_EXT_WDTR_BUS_8_BIT)
                        targ->dv_next_narrow_period = AHD_ASYNC_XFER_PERIOD;
                else
                        targ->dv_next_wide_period = AHD_ASYNC_XFER_PERIOD;
        }
        ahd_set_syncrate(ahd, devinfo, period, offset,
                         ppr_options, AHD_TRANS_GOAL, FALSE);
        targ->dv_last_ppr_options = ppr_options;
        return (0);
}

static void
ahd_linux_dv_timeout(struct scsi_cmnd *cmd)
{
        struct  ahd_softc *ahd;
        struct  scb *scb;
        u_long  flags;

        ahd = *((struct ahd_softc **)cmd->device->host->hostdata);
        ahd_lock(ahd, &flags);

#ifdef AHD_DEBUG
        if (ahd_debug & AHD_SHOW_DV) {
                printf("%s: Timeout while doing DV command %x.\n",
                       ahd_name(ahd), cmd->cmnd[0]);
                ahd_dump_card_state(ahd);
        }
#endif
        
        /*
         * Guard against "done race".  No action is
         * required if we just completed.
         */
        if ((scb = (struct scb *)cmd->host_scribble) == NULL) {
                ahd_unlock(ahd, &flags);
                return;
        }

        /*
         * Command has not completed.  Mark this
         * SCB as having failing status prior to
         * resetting the bus, so we get the correct
         * error code.
         */
        if ((scb->flags & SCB_SENSE) != 0)
                ahd_set_transaction_status(scb, CAM_AUTOSENSE_FAIL);
        else
                ahd_set_transaction_status(scb, CAM_CMD_TIMEOUT);
        ahd_reset_channel(ahd, cmd->device->channel + 'A', /*initiate*/TRUE);

        /*
         * Add a minimal bus settle delay for devices that are slow to
         * respond after bus resets.
         */
        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 + HZ / 2;
        ahd->platform_data->reset_timer.function =
            (ahd_linux_callback_t *)ahd_release_simq;
        add_timer(&ahd->platform_data->reset_timer);
        if (ahd_linux_next_device_to_run(ahd) != NULL)
                ahd_schedule_runq(ahd);
        ahd_linux_run_complete_queue(ahd);
        ahd_unlock(ahd, &flags);
}

static void
ahd_linux_dv_complete(struct scsi_cmnd *cmd)
{
        struct ahd_softc *ahd;

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

        /* Delete the DV timer before it goes off! */
        scsi_delete_timer(cmd);

#ifdef AHD_DEBUG
        if (ahd_debug & AHD_SHOW_DV)
                printf("%s:%c:%d: Command completed, status= 0x%x\n",
                       ahd_name(ahd), cmd->device->channel, cmd->device->id,
                       cmd->result);
#endif

        /* Wake up the state machine */
        up(&ahd->platform_data->dv_cmd_sem);
}

static void
ahd_linux_generate_dv_pattern(struct ahd_linux_target *targ)
{
        uint16_t b;
        u_int    i;
        u_int    j;

        if (targ->dv_buffer != NULL)
                free(targ->dv_buffer, M_DEVBUF);
        targ->dv_buffer = malloc(targ->dv_echo_size, M_DEVBUF, M_WAITOK);
        if (targ->dv_buffer1 != NULL)
                free(targ->dv_buffer1, M_DEVBUF);
        targ->dv_buffer1 = malloc(targ->dv_echo_size, M_DEVBUF, M_WAITOK);

        i = 0;

        b = 0x0001;
        for (j = 0 ; i < targ->dv_echo_size; j++) {
                if (j < 32) {
                        /*
                         * 32bytes of sequential numbers.
                         */
                        targ->dv_buffer[i++] = j & 0xff;
                } else if (j < 48) {
                        /*
                         * 32bytes of repeating 0x0000, 0xffff.
                         */
                        targ->dv_buffer[i++] = (j & 0x02) ? 0xff : 0x00;
                } else if (j < 64) {
                        /*
                         * 32bytes of repeating 0x5555, 0xaaaa.
                         */
                        targ->dv_buffer[i++] = (j & 0x02) ? 0xaa : 0x55;
                } else {
                        /*
                         * Remaining buffer is filled with a repeating
                         * patter of:
                         *
                         *       0xffff
                         *      ~0x0001 << shifted once in each loop.
                         */
                        if (j & 0x02) {
                                if (j & 0x01) {
                                        targ->dv_buffer[i++] = ~(b >> 8) & 0xff;
                                        b <<= 1;
                                        if (b == 0x0000)
                                                b = 0x0001;
                                } else {
                                        targ->dv_buffer[i++] = (~b & 0xff);
                                }
                        } else {
                                targ->dv_buffer[i++] = 0xff;
                        }
                }
        }
}

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);
}

static u_int
ahd_linux_user_dv_setting(struct ahd_softc *ahd)
{
        static int warned_user;
        int dv;

        if (ahd->unit >= NUM_ELEMENTS(aic79xx_dv_settings)) {

                if (warned_user == 0) {
                        printf(KERN_WARNING
"aic79xx: WARNING: Insufficient dv settings instances\n"
"aic79xx: for installed controllers. Using defaults\n"
"aic79xx: Please update the aic79xx_dv_settings array in"
"aic79xx: the aic79xx_osm.c source file.\n");
                        warned_user++;
                }
                dv = -1;
        } else {

                dv = aic79xx_dv_settings[ahd->unit];
        }

        if (dv < 0) {
                /*
                 * Apply the default.
                 */
                dv = 1;
                if (ahd->seep_config != 0)
                        dv = (ahd->seep_config->bios_control & CFENABLEDV);
        }
        return (dv);
}

static void
ahd_linux_setup_user_rd_strm_settings(struct ahd_softc *ahd)
{
        static  int warned_user;
        u_int   rd_strm_mask;
        u_int   target_id;

        /*
         * If we have specific read streaming info for this controller,
         * apply it.  Otherwise use the defaults.
         */
         if (ahd->unit >= NUM_ELEMENTS(aic79xx_rd_strm_info)) {

                if (warned_user == 0) {

                        printf(KERN_WARNING
"aic79xx: WARNING: Insufficient rd_strm instances\n"
"aic79xx: for installed controllers. Using defaults\n"
"aic79xx: Please update the aic79xx_rd_strm_info array\n"
"aic79xx: in the aic79xx_osm.c source file.\n");
                        warned_user++;
                }
                rd_strm_mask = AIC79XX_CONFIGED_RD_STRM;
        } else {

                rd_strm_mask = aic79xx_rd_strm_info[ahd->unit];
        }
        for (target_id = 0; target_id < 16; 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);
                tinfo->user.ppr_options &= ~MSG_EXT_PPR_RD_STRM;
                if ((rd_strm_mask & devinfo.target_mask) != 0)
                        tinfo->user.ppr_options |= MSG_EXT_PPR_RD_STRM;
        }
}

/*
 * Determines the queue depth for a given device.
 */
static void
ahd_linux_device_queue_depth(struct ahd_softc *ahd,
                             struct ahd_linux_device *dev)
{
        struct  ahd_devinfo devinfo;
        u_int   tags;

        ahd_compile_devinfo(&devinfo,
                            ahd->our_id,
                            dev->target->target, dev->lun,
                            dev->target->channel == 0 ? 'A' : 'B',
                            ROLE_INITIATOR);
        tags = ahd_linux_user_tagdepth(ahd, &devinfo);
        if (tags != 0
         && dev->scsi_device != NULL
         && dev->scsi_device->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 void
ahd_linux_run_device_queue(struct ahd_softc *ahd, struct ahd_linux_device *dev)
{
        struct   ahd_cmd *acmd;
        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;

        if ((dev->flags & AHD_DEV_ON_RUN_LIST) != 0)
                panic("running device on run list");

        while ((acmd = TAILQ_FIRST(&dev->busyq)) != NULL
            && dev->openings > 0 && dev->qfrozen == 0) {

                /*
                 * Schedule us to run later.  The only reason we are not
                 * running is because the whole controller Q is frozen.
                 */
                if (ahd->platform_data->qfrozen != 0
                 && AHD_DV_SIMQ_FROZEN(ahd) == 0) {

                        TAILQ_INSERT_TAIL(&ahd->platform_data->device_runq,
                                          dev, links);
                        dev->flags |= AHD_DEV_ON_RUN_LIST;
                        return;
                }

                cmd = &acmd_scsi_cmd(acmd);

                /*
                 * 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) {
                        TAILQ_INSERT_TAIL(&ahd->platform_data->device_runq,
                                         dev, links);
                        dev->flags |= AHD_DEV_ON_RUN_LIST;
                        ahd->flags |= AHD_RESOURCE_SHORTAGE;
                        return;
                }
                TAILQ_REMOVE(&dev->busyq, acmd, acmd_links.tqe);
                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 (AHD_DV_CMD(cmd) != 0)
                        scb->flags |= SCB_SILENT;

                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) {
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
                        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
#endif
                        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->sg_count = 0;
                ahd_set_residual(scb, 0);
                ahd_set_sense_residual(scb, 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++;

                /* Update the error counting bucket and dump if needed */
                if (dev->target->cmds_since_error) {
                        dev->target->cmds_since_error++;
                        if (dev->target->cmds_since_error >
                            AHD_LINUX_ERR_THRESH)
                                dev->target->cmds_since_error = 0;
                }

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

/*
 * 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);
        if (ahd_linux_next_device_to_run(ahd) != NULL)
                ahd_schedule_runq(ahd);
        ahd_linux_run_complete_queue(ahd);
        ahd_unlock(ahd, &flags);
        return IRQ_RETVAL(ours);
}

void
ahd_platform_flushwork(struct ahd_softc *ahd)
{

        while (ahd_linux_run_complete_queue(ahd) != NULL)
                ;
}

static struct ahd_linux_target*
ahd_linux_alloc_target(struct ahd_softc *ahd, u_int channel, u_int target)
{
        struct ahd_linux_target *targ;

        targ = malloc(sizeof(*targ), M_DEVBUF, M_NOWAIT);
        if (targ == NULL)
                return (NULL);
        memset(targ, 0, sizeof(*targ));
        targ->channel = channel;
        targ->target = target;
        targ->ahd = ahd;
        targ->flags = AHD_DV_REQUIRED;
        ahd->platform_data->targets[target] = targ;
        return (targ);
}

static void
ahd_linux_free_target(struct ahd_softc *ahd, struct ahd_linux_target *targ)
{
        struct ahd_devinfo devinfo;
        struct ahd_initiator_tinfo *tinfo;
        struct ahd_tmode_tstate *tstate;
        u_int our_id;
        u_int target_offset;
        char channel;

        /*
         * Force a negotiation to async/narrow on any
         * future command to this device unless a bus
         * reset occurs between now and that command.
         */
        channel = 'A' + targ->channel;
        our_id = ahd->our_id;
        target_offset = targ->target;
        tinfo = ahd_fetch_transinfo(ahd, channel, our_id,
                                    targ->target, &tstate);
        ahd_compile_devinfo(&devinfo, our_id, targ->target, CAM_LUN_WILDCARD,
                            channel, ROLE_INITIATOR);
        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_update_neg_request(ahd, &devinfo, tstate, tinfo, AHD_NEG_ALWAYS);
        ahd->platform_data->targets[target_offset] = NULL;
        if (targ->inq_data != NULL)
                free(targ->inq_data, M_DEVBUF);
        if (targ->dv_buffer != NULL)
                free(targ->dv_buffer, M_DEVBUF);
        if (targ->dv_buffer1 != NULL)
                free(targ->dv_buffer1, M_DEVBUF);
        free(targ, M_DEVBUF);
}

static struct ahd_linux_device*
ahd_linux_alloc_device(struct ahd_softc *ahd,
                 struct ahd_linux_target *targ, u_int lun)
{
        struct ahd_linux_device *dev;

        dev = malloc(sizeof(*dev), M_DEVBUG, M_NOWAIT);
        if (dev == NULL)
                return (NULL);
        memset(dev, 0, sizeof(*dev));
        init_timer(&dev->timer);
        TAILQ_INIT(&dev->busyq);
        dev->flags = AHD_DEV_UNCONFIGURED;
        dev->lun = lun;
        dev->target = targ;

        /*
         * 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->refcount++;
        targ->devices[lun] = dev;
        return (dev);
}

static void
ahd_linux_free_device(struct ahd_softc *ahd, struct ahd_linux_device *dev)
{
        struct ahd_linux_target *targ;

        del_timer(&dev->timer);
        targ = dev->target;
        targ->devices[dev->lun] = NULL;
        free(dev, M_DEVBUF);
        targ->refcount--;
        if (targ->refcount == 0
         && (targ->flags & AHD_DV_REQUIRED) == 0)
                ahd_linux_free_target(ahd, targ);
}

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  ahd_linux_target *targ;
                struct  info_str info;
                struct  ahd_initiator_tinfo *tinfo;
                struct  ahd_tmode_tstate *tstate;

                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.
                 */
                targ = ahd->platform_data->targets[target];
                if (targ == NULL)
                        break;
                if (tinfo->curr.period == targ->last_tinfo.period
                 && tinfo->curr.width == targ->last_tinfo.width
                 && tinfo->curr.offset == targ->last_tinfo.offset
                 && tinfo->curr.ppr_options == targ->last_tinfo.ppr_options)
                        if (bootverbose == 0)
                                break;

                targ->last_tinfo.period = tinfo->curr.period;
                targ->last_tinfo.width = tinfo->curr.width;
                targ->last_tinfo.offset = tinfo->curr.offset;
                targ->last_tinfo.ppr_options = tinfo->curr.ppr_options;

                printf("(%s:%c:", ahd_name(ahd), channel);
                if (target == CAM_TARGET_WILDCARD)
                        printf("*): ");
                else
                        printf("%d): ", target);
                ahd_format_transinfo(&info, &tinfo->curr);
                if (info.pos < info.length)
                        *info.buffer = '\0';
                else
                        buf[info.length - 1] = '\0';
                printf("%s", buf);
                break;
        }
        case AC_SENT_BDR:
        {
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
                WARN_ON(lun != CAM_LUN_WILDCARD);
                scsi_report_device_reset(ahd->platform_data->host,
                                         channel - 'A', target);
#else
                Scsi_Device *scsi_dev;

                /*
                 * Find the SCSI device associated with this
                 * request and indicate that a UA is expected.
                 */
                for (scsi_dev = ahd->platform_data->host->host_queue;
                     scsi_dev != NULL; scsi_dev = scsi_dev->next) {
                        if (channel - 'A' == scsi_dev->channel
                         && target == scsi_dev->id
                         && (lun == CAM_LUN_WILDCARD
                          || lun == scsi_dev->lun)) {
                                scsi_dev->was_reset = 1;
                                scsi_dev->expecting_cc_ua = 1;
                        }
                }
#endif
                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)
{
        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, dev, scb);
        } else if (ahd_get_transaction_status(scb) == CAM_SEL_TIMEOUT) {
                dev->flags |= AHD_DEV_UNCONFIGURED;
                if (AHD_DV_CMD(cmd) == FALSE)
                        dev->target->flags &= ~AHD_DV_REQUIRED;
        }
        /*
         * Start DV for devices that require it assuming the first command
         * sent does not result in a selection timeout.
         */
        if (ahd_get_transaction_status(scb) != CAM_SEL_TIMEOUT
         && (dev->target->flags & AHD_DV_REQUIRED) != 0)
                ahd_linux_start_dv(ahd);

        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 (TAILQ_EMPTY(&dev->busyq)) {
                if ((dev->flags & AHD_DEV_UNCONFIGURED) != 0
                 && dev->active == 0
                 && (dev->flags & AHD_DEV_TIMER_ACTIVE) == 0)
                        ahd_linux_free_device(ahd, dev);
        } else if ((dev->flags & AHD_DEV_ON_RUN_LIST) == 0) {
                TAILQ_INSERT_TAIL(&ahd->platform_data->device_runq, dev, links);
                dev->flags |= AHD_DEV_ON_RUN_LIST;
        }

        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 ((scb->platform_data->flags & AHD_SCB_UP_EH_SEM) != 0) {
                        scb->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);

        if ((ahd->platform_data->flags & AHD_DV_WAIT_SIMQ_EMPTY) != 0
         && LIST_FIRST(&ahd->pending_scbs) == NULL) {
                ahd->platform_data->flags &= ~AHD_DV_WAIT_SIMQ_EMPTY;
                up(&ahd->platform_data->dv_sem);
        }
}

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

        ahd_compile_devinfo(&devinfo,
                            ahd->our_id,
                            dev->target->target, dev->lun,
                            dev->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:
        {
                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);
                /* FALLTHROUGH */
        }
        case SCSI_STATUS_BUSY:
                /*
                 * Set a short timer to defer sending commands for
                 * a bit since Linux will not delay in this case.
                 */
                if ((dev->flags & AHD_DEV_TIMER_ACTIVE) != 0) {
                        printf("%s:%c:%d: Device Timer still active during "
                               "busy processing\n", ahd_name(ahd),
                                dev->target->channel, dev->target->target);
                        break;
                }
                dev->flags |= AHD_DEV_TIMER_ACTIVE;
                dev->qfrozen++;
                init_timer(&dev->timer);
                dev->timer.data = (u_long)dev;
                dev->timer.expires = jiffies + (HZ/2);
                dev->timer.function = ahd_linux_dev_timed_unfreeze;
                add_timer(&dev->timer);
                break;
        }
}

static void
ahd_linux_queue_cmd_complete(struct ahd_softc *ahd, Scsi_Cmnd *cmd)
{
        /*
         * Typically, the complete queue has very few entries
         * queued to it before the queue is emptied by
         * ahd_linux_run_complete_queue, so sorting the entries
         * by generation number should be inexpensive.
         * We perform the sort so that commands that complete
         * with an error are retuned in the order origionally
         * queued to the controller so that any subsequent retries
         * are performed in order.  The underlying ahd routines do
         * not guarantee the order that aborted commands will be
         * returned to us.
         */
        struct ahd_completeq *completeq;
        struct ahd_cmd *list_cmd;
        struct ahd_cmd *acmd;

        /*
         * 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.
         */
        if (AHD_DV_CMD(cmd) == FALSE) {
                uint32_t status;
                u_int new_status;

                status = ahd_cmd_get_transaction_status(cmd);
                if (status != CAM_REQ_CMP) {
                        struct ahd_linux_device *dev;
                        struct ahd_devinfo devinfo;
                        cam_status cam_status;
                        uint32_t action;
                        u_int scsi_status;

                        dev = ahd_linux_get_device(ahd, cmd->device->channel,
                                                   cmd->device->id,
                                                   cmd->device->lun,
                                                   /*alloc*/FALSE);

                        if (dev == NULL)
                                goto no_fallback;

                        ahd_compile_devinfo(&devinfo,
                                            ahd->our_id,
                                            dev->target->target, dev->lun,
                                            dev->target->channel == 0 ? 'A':'B',
                                            ROLE_INITIATOR);

                        scsi_status = ahd_cmd_get_scsi_status(cmd);
                        cam_status = ahd_cmd_get_transaction_status(cmd);
                        action = aic_error_action(cmd, dev->target->inq_data,
                                                  cam_status, scsi_status);
                        if ((action & SSQ_FALLBACK) != 0) {

                                /* Update stats */
                                dev->target->errors_detected++;
                                if (dev->target->cmds_since_error == 0)
                                        dev->target->cmds_since_error++;
                                else {
                                        dev->target->cmds_since_error = 0;
                                        ahd_linux_fallback(ahd, &devinfo);
                                }
                        }
                }
no_fallback:
                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:
                        /*
                         * If we want the request requeued, make sure there
                         * are sufficent retries.  In the old scsi error code,
                         * we used to be able to specify a result code that
                         * bypassed the retry count.  Now we must use this
                         * hack.  We also "fake" a check condition with
                         * a sense code of ABORTED COMMAND.  This seems to
                         * evoke a retry even if this command is being sent
                         * via the eh thread.  Ick!  Ick!  Ick!
                         */
                        if (cmd->retries > 0)
                                cmd->retries--;
                        new_status = DID_OK;
                        ahd_cmd_set_scsi_status(cmd, SCSI_STATUS_CHECK_COND);
                        cmd->result |= (DRIVER_SENSE << 24);
                        memset(cmd->sense_buffer, 0,
                               sizeof(cmd->sense_buffer));
                        cmd->sense_buffer[0] = SSD_ERRCODE_VALID
                                             | SSD_CURRENT_ERROR;
                        cmd->sense_buffer[2] = SSD_KEY_ABORTED_COMMAND;
                        break;
                default:
                        /* We should never get here */
                        new_status = DID_ERROR;
                        break;
                }

                ahd_cmd_set_transaction_status(cmd, new_status);
        }

        completeq = &ahd->platform_data->completeq;
        list_cmd = TAILQ_FIRST(completeq);
        acmd = (struct ahd_cmd *)cmd;
        while (list_cmd != NULL
            && acmd_scsi_cmd(list_cmd).serial_number
             < acmd_scsi_cmd(acmd).serial_number)
                list_cmd = TAILQ_NEXT(list_cmd, acmd_links.tqe);
        if (list_cmd != NULL)
                TAILQ_INSERT_BEFORE(list_cmd, acmd, acmd_links.tqe);
        else
                TAILQ_INSERT_TAIL(completeq, acmd, acmd_links.tqe);
}

static void
ahd_linux_filter_inquiry(struct ahd_softc *ahd, struct ahd_devinfo *devinfo)
{
        struct  scsi_inquiry_data *sid;
        struct  ahd_initiator_tinfo *tinfo;
        struct  ahd_transinfo *user;
        struct  ahd_transinfo *goal;
        struct  ahd_transinfo *curr;
        struct  ahd_tmode_tstate *tstate;
        struct  ahd_linux_device *dev;
        u_int   width;
        u_int   period;
        u_int   offset;
        u_int   ppr_options;
        u_int   trans_version;
        u_int   prot_version;

        /*
         * Determine if this lun actually exists.  If so,
         * hold on to its corresponding device structure.
         * If not, make sure we release the device and
         * don't bother processing the rest of this inquiry
         * command.
         */
        dev = ahd_linux_get_device(ahd, devinfo->channel - 'A',
                                   devinfo->target, devinfo->lun,
                                   /*alloc*/TRUE);

        sid = (struct scsi_inquiry_data *)dev->target->inq_data;
        if (SID_QUAL(sid) == SID_QUAL_LU_CONNECTED) {

                dev->flags &= ~AHD_DEV_UNCONFIGURED;
        } else {
                dev->flags |= AHD_DEV_UNCONFIGURED;
                return;
        }

        /*
         * Update our notion of this device's transfer
         * negotiation capabilities.
         */
        tinfo = ahd_fetch_transinfo(ahd, devinfo->channel,
                                    devinfo->our_scsiid,
                                    devinfo->target, &tstate);
        user = &tinfo->user;
        goal = &tinfo->goal;
        curr = &tinfo->curr;
        width = user->width;
        period = user->period;
        offset = user->offset;
        ppr_options = user->ppr_options;
        trans_version = user->transport_version;
        prot_version = MIN(user->protocol_version, SID_ANSI_REV(sid));

        /*
         * Only attempt SPI3/4 once we've verified that
         * the device claims to support SPI3/4 features.
         */
        if (prot_version < SCSI_REV_2)
                trans_version = SID_ANSI_REV(sid);
        else
                trans_version = SCSI_REV_2;

        if ((sid->flags & SID_WBus16) == 0)
                width = MSG_EXT_WDTR_BUS_8_BIT;
        if ((sid->flags & SID_Sync) == 0) {
                period = 0;
                offset = 0;
                ppr_options = 0;
        }
        if ((sid->spi3data & SID_SPI_QAS) == 0)
                ppr_options &= ~MSG_EXT_PPR_QAS_REQ;
        if ((sid->spi3data & SID_SPI_CLOCK_DT) == 0)
                ppr_options &= MSG_EXT_PPR_QAS_REQ;
        if ((sid->spi3data & SID_SPI_IUS) == 0)
                ppr_options &= (MSG_EXT_PPR_DT_REQ
                              | MSG_EXT_PPR_QAS_REQ);

        if (prot_version > SCSI_REV_2
         && ppr_options != 0)
                trans_version = user->transport_version;

        ahd_validate_width(ahd, /*tinfo limit*/NULL, &width, ROLE_UNKNOWN);
        ahd_find_syncrate(ahd, &period, &ppr_options, AHD_SYNCRATE_MAX);
        ahd_validate_offset(ahd, /*tinfo limit*/NULL, period,
                            &offset, width, ROLE_UNKNOWN);
        if (offset == 0 || period == 0) {
                period = 0;
                offset = 0;
                ppr_options = 0;
        }
        /* Apply our filtered user settings. */
        curr->transport_version = trans_version;
        curr->protocol_version = prot_version;
        ahd_set_width(ahd, devinfo, width, AHD_TRANS_GOAL, /*paused*/FALSE);
        ahd_set_syncrate(ahd, devinfo, period, offset, ppr_options,
                         AHD_TRANS_GOAL, /*paused*/FALSE);
}

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;
        }
        if (AHD_DV_SIMQ_FROZEN(ahd)
         && ((ahd->platform_data->flags & AHD_DV_WAIT_SIMQ_RELEASE) != 0)) {
                ahd->platform_data->flags &= ~AHD_DV_WAIT_SIMQ_RELEASE;
                up(&ahd->platform_data->dv_sem);
        }
        ahd_schedule_runq(ahd);
        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 void
ahd_linux_sem_timeout(u_long arg)
{
        struct  scb *scb;
        struct  ahd_softc *ahd;
        u_long  s;

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

static void
ahd_linux_dev_timed_unfreeze(u_long arg)
{
        struct ahd_linux_device *dev;
        struct ahd_softc *ahd;
        u_long s;

        dev = (struct ahd_linux_device *)arg;
        ahd = dev->target->ahd;
        ahd_lock(ahd, &s);
        dev->flags &= ~AHD_DEV_TIMER_ACTIVE;
        if (dev->qfrozen > 0)
                dev->qfrozen--;
        if (dev->qfrozen == 0
         && (dev->flags & AHD_DEV_ON_RUN_LIST) == 0)
                ahd_linux_run_device_queue(ahd, dev);
        if ((dev->flags & AHD_DEV_UNCONFIGURED) != 0
         && dev->active == 0)
                ahd_linux_free_device(ahd, dev);
        ahd_unlock(ahd, &s);
}

void
ahd_platform_dump_card_state(struct ahd_softc *ahd)
{
        struct ahd_linux_device *dev;
        int target;
        int maxtarget;
        int lun;
        int i;

        maxtarget = (ahd->features & AHD_WIDE) ? 15 : 7;
        for (target = 0; target <=maxtarget; target++) {

                for (lun = 0; lun < AHD_NUM_LUNS; lun++) {
                        struct ahd_cmd *acmd;

                        dev = ahd_linux_get_device(ahd, 0, target,
                                                   lun, /*alloc*/FALSE);
                        if (dev == NULL)
                                continue;

                        printf("DevQ(%d:%d:%d): ", 0, target, lun);
                        i = 0;
                        TAILQ_FOREACH(acmd, &dev->busyq, acmd_links.tqe) {
                                if (i++ > AHD_SCB_MAX)
                                        break;
                        }
                        printf("%d waiting\n", i);
                }
        }
}

static int __init
ahd_linux_init(void)
{
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
        return ahd_linux_detect(&aic79xx_driver_template);
#else
        scsi_register_module(MODULE_SCSI_HA, &aic79xx_driver_template);
        if (aic79xx_driver_template.present == 0) {
                scsi_unregister_module(MODULE_SCSI_HA,
                                       &aic79xx_driver_template);
                return (-ENODEV);
        }

        return (0);
#endif
}

static void __exit
ahd_linux_exit(void)
{
        struct ahd_softc *ahd;

        /*
         * Shutdown DV threads before going into the SCSI mid-layer.
         * This avoids situations where the mid-layer locks the entire
         * kernel so that waiting for our DV threads to exit leads
         * to deadlock.
         */
        TAILQ_FOREACH(ahd, &ahd_tailq, links) {

                ahd_linux_kill_dv_thread(ahd);
        }

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0)
        /*
         * In 2.4 we have to unregister from the PCI core _after_
         * unregistering from the scsi midlayer to avoid dangling
         * references.
         */
        scsi_unregister_module(MODULE_SCSI_HA, &aic79xx_driver_template);
#endif
        ahd_linux_pci_exit();
}

module_init(ahd_linux_init);
module_exit(ahd_linux_exit);