Merge master.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-for-linus-2.6

[linux-2.6] / drivers / scsi / aic7xxx / aic7xxx_osm.c

/*
 * Adaptec AIC7xxx device driver for Linux.
 *
 * $Id: //depot/aic7xxx/linux/drivers/scsi/aic7xxx/aic7xxx_osm.c#235 $
 *
 * Copyright (c) 1994 John Aycock
 *   The University of Calgary Department of Computer Science.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * Sources include the Adaptec 1740 driver (aha1740.c), the Ultrastor 24F
 * driver (ultrastor.c), various Linux kernel source, the Adaptec EISA
 * config file (!adp7771.cfg), the Adaptec AHA-2740A Series User's Guide,
 * the Linux Kernel Hacker's Guide, Writing a SCSI Device Driver for Linux,
 * the Adaptec 1542 driver (aha1542.c), the Adaptec EISA overlay file
 * (adp7770.ovl), the Adaptec AHA-2740 Series Technical Reference Manual,
 * the Adaptec AIC-7770 Data Book, the ANSI SCSI specification, the
 * ANSI SCSI-2 specification (draft 10c), ...
 *
 * --------------------------------------------------------------------------
 *
 *  Modifications by Daniel M. Eischen (deischen@iworks.InterWorks.org):
 *
 *  Substantially modified to include support for wide and twin bus
 *  adapters, DMAing of SCBs, tagged queueing, IRQ sharing, bug fixes,
 *  SCB paging, and other rework of the code.
 *
 * --------------------------------------------------------------------------
 * Copyright (c) 1994-2000 Justin T. Gibbs.
 * Copyright (c) 2000-2001 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.
 *
 *---------------------------------------------------------------------------
 *
 *  Thanks also go to (in alphabetical order) the following:
 *
 *    Rory Bolt     - Sequencer bug fixes
 *    Jay Estabrook - Initial DEC Alpha support
 *    Doug Ledford  - Much needed abort/reset bug fixes
 *    Kai Makisara  - DMAing of SCBs
 *
 *  A Boot time option was also added for not resetting the scsi bus.
 *
 *    Form:  aic7xxx=extended
 *           aic7xxx=no_reset
 *           aic7xxx=verbose
 *
 *  Daniel M. Eischen, deischen@iworks.InterWorks.org, 1/23/97
 *
 *  Id: aic7xxx.c,v 4.1 1997/06/12 08:23:42 deang Exp
 */

/*
 * Further driver modifications made by Doug Ledford <dledford@redhat.com>
 *
 * Copyright (c) 1997-1999 Doug Ledford
 *
 * These changes are released under the same licensing terms as the FreeBSD
 * driver written by Justin Gibbs.  Please see his Copyright notice above
 * for the exact terms and conditions covering my changes as well as the
 * warranty statement.
 *
 * Modifications made to the aic7xxx.c,v 4.1 driver from Dan Eischen include
 * but are not limited to:
 *
 *  1: Import of the latest FreeBSD sequencer code for this driver
 *  2: Modification of kernel code to accommodate different sequencer semantics
 *  3: Extensive changes throughout kernel portion of driver to improve
 *     abort/reset processing and error hanndling
 *  4: Other work contributed by various people on the Internet
 *  5: Changes to printk information and verbosity selection code
 *  6: General reliability related changes, especially in IRQ management
 *  7: Modifications to the default probe/attach order for supported cards
 *  8: SMP friendliness has been improved
 *
 */

#include "aic7xxx_osm.h"
#include "aic7xxx_inline.h"
#include <scsi/scsicam.h>

static struct scsi_transport_template *ahc_linux_transport_template = NULL;

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

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


/*
 * 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_AIC7XXX_RESET_DELAY_MS
#define AIC7XXX_RESET_DELAY CONFIG_AIC7XXX_RESET_DELAY_MS
#else
#define AIC7XXX_RESET_DELAY 5000
#endif

/*
 * Control collection of SCSI transfer statistics for the /proc filesystem.
 *
 * NOTE: Do NOT enable this when running on kernels version 1.2.x and below.
 * NOTE: This does affect performance since it has to maintain statistics.
 */
#ifdef CONFIG_AIC7XXX_PROC_STATS
#define AIC7XXX_PROC_STATS
#endif

/*
 * To change the default number of tagged transactions allowed per-device,
 * add a line to the lilo.conf file like:
 * append="aic7xxx=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 {
        uint8_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 aic7xxx 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 aic7xxx_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_AIC7XXX_CMDS_PER_DEVICE
#define AIC7XXX_CMDS_PER_DEVICE CONFIG_AIC7XXX_CMDS_PER_DEVICE
#else
#define AIC7XXX_CMDS_PER_DEVICE AHC_MAX_QUEUE
#endif

#define AIC7XXX_CONFIGED_TAG_COMMANDS {                                 \
        AIC7XXX_CMDS_PER_DEVICE, AIC7XXX_CMDS_PER_DEVICE,               \
        AIC7XXX_CMDS_PER_DEVICE, AIC7XXX_CMDS_PER_DEVICE,               \
        AIC7XXX_CMDS_PER_DEVICE, AIC7XXX_CMDS_PER_DEVICE,               \
        AIC7XXX_CMDS_PER_DEVICE, AIC7XXX_CMDS_PER_DEVICE,               \
        AIC7XXX_CMDS_PER_DEVICE, AIC7XXX_CMDS_PER_DEVICE,               \
        AIC7XXX_CMDS_PER_DEVICE, AIC7XXX_CMDS_PER_DEVICE,               \
        AIC7XXX_CMDS_PER_DEVICE, AIC7XXX_CMDS_PER_DEVICE,               \
        AIC7XXX_CMDS_PER_DEVICE, AIC7XXX_CMDS_PER_DEVICE                \
}

/*
 * By default, use the number of commands specified by
 * the users kernel configuration.
 */
static adapter_tag_info_t aic7xxx_tag_info[] =
{
        {AIC7XXX_CONFIGED_TAG_COMMANDS},
        {AIC7XXX_CONFIGED_TAG_COMMANDS},
        {AIC7XXX_CONFIGED_TAG_COMMANDS},
        {AIC7XXX_CONFIGED_TAG_COMMANDS},
        {AIC7XXX_CONFIGED_TAG_COMMANDS},
        {AIC7XXX_CONFIGED_TAG_COMMANDS},
        {AIC7XXX_CONFIGED_TAG_COMMANDS},
        {AIC7XXX_CONFIGED_TAG_COMMANDS},
        {AIC7XXX_CONFIGED_TAG_COMMANDS},
        {AIC7XXX_CONFIGED_TAG_COMMANDS},
        {AIC7XXX_CONFIGED_TAG_COMMANDS},
        {AIC7XXX_CONFIGED_TAG_COMMANDS},
        {AIC7XXX_CONFIGED_TAG_COMMANDS},
        {AIC7XXX_CONFIGED_TAG_COMMANDS},
        {AIC7XXX_CONFIGED_TAG_COMMANDS},
        {AIC7XXX_CONFIGED_TAG_COMMANDS}
};

/*
 * 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
ahc_print_path(struct ahc_softc *ahc, struct scb *scb)
{
        printk("(scsi%d:%c:%d:%d): ",
               ahc->platform_data->host->host_no,
               scb != NULL ? SCB_GET_CHANNEL(ahc, scb) : 'X',
               scb != NULL ? SCB_GET_TARGET(ahc, scb) : -1,
               scb != NULL ? SCB_GET_LUN(scb) : -1);
}

/*
 * XXX - these options apply unilaterally to _all_ 274x/284x/294x
 *       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 aic7xxx_no_reset;

/*
 * 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 aic7xxx_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 where stray PCI transactions with bad parity are
 * the norm rather than the exception, the error messages can be overwelming.
 * It's included in the driver for completeness.
 *   0     = Shut off PCI parity check
 *   non-0 = reverse polarity pci parity checking
 */
static uint32_t aic7xxx_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 aic7xxx_allow_memio = ~0;

/*
 * 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 aic7xxx_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 aic7xxx_periodic_otag;

/*
 * Module information and settable options.
 */
static char *aic7xxx = NULL;

MODULE_AUTHOR("Maintainer: Justin T. Gibbs <gibbs@scsiguy.com>");
MODULE_DESCRIPTION("Adaptec Aic77XX/78XX SCSI Host Bus Adapter driver");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_VERSION(AIC7XXX_DRIVER_VERSION);
module_param(aic7xxx, charp, 0444);
MODULE_PARM_DESC(aic7xxx,
"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_probe                Toggle EISA/VLB controller probing\n"
"       probe_eisa_vl           Toggle EISA/VLB controller probing\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"
"                               drives or 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 every target\n"
"                               on every bus\n"
"       seltime:<int>           Selection Timeout\n"
"                               (0/256ms,1/128ms,2/64ms,3/32ms)\n"
"\n"
"       Sample /etc/modprobe.conf line:\n"
"               Toggle EISA/VLB probing\n"
"               Set tag depth on Controller 1/Target 1 to 10 tags\n"
"               Shorten the selection timeout to 128ms\n"
"\n"
"       options aic7xxx 'aic7xxx=probe_eisa_vl.tag_info:{{}.{.10}}.seltime:1'\n"
);

static void ahc_linux_handle_scsi_status(struct ahc_softc *,
                                         struct scsi_device *,
                                         struct scb *);
static void ahc_linux_queue_cmd_complete(struct ahc_softc *ahc,
                                         struct scsi_cmnd *cmd);
static void ahc_linux_sem_timeout(u_long arg);
static void ahc_linux_freeze_simq(struct ahc_softc *ahc);
static void ahc_linux_release_simq(u_long arg);
static int  ahc_linux_queue_recovery_cmd(struct scsi_cmnd *cmd, scb_flag flag);
static void ahc_linux_initialize_scsi_bus(struct ahc_softc *ahc);
static u_int ahc_linux_user_tagdepth(struct ahc_softc *ahc,
                                     struct ahc_devinfo *devinfo);
static void ahc_linux_device_queue_depth(struct scsi_device *);
static int ahc_linux_run_command(struct ahc_softc*,
                                 struct ahc_linux_device *,
                                 struct scsi_cmnd *);
static void ahc_linux_setup_tag_info_global(char *p);
static aic_option_callback_t ahc_linux_setup_tag_info;
static int  aic7xxx_setup(char *s);

static int ahc_linux_unit;


/********************************* Inlines ************************************/
static __inline void ahc_linux_unmap_scb(struct ahc_softc*, struct scb*);

static __inline int ahc_linux_map_seg(struct ahc_softc *ahc, struct scb *scb,
                                      struct ahc_dma_seg *sg,
                                      dma_addr_t addr, bus_size_t len);

static __inline void
ahc_linux_unmap_scb(struct ahc_softc *ahc, struct scb *scb)
{
        struct scsi_cmnd *cmd;

        cmd = scb->io_ctx;
        ahc_sync_sglist(ahc, scb, BUS_DMASYNC_POSTWRITE);
        if (cmd->use_sg != 0) {
                struct scatterlist *sg;

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

static __inline int
ahc_linux_map_seg(struct ahc_softc *ahc, struct scb *scb,
                  struct ahc_dma_seg *sg, dma_addr_t addr, bus_size_t len)
{
        int      consumed;

        if ((scb->sg_count + 1) > AHC_NSEG)
                panic("Too few segs for dma mapping.  "
                      "Increase AHC_NSEG\n");

        consumed = 1;
        sg->addr = ahc_htole32(addr & 0xFFFFFFFF);
        scb->platform_data->xfer_len += len;

        if (sizeof(dma_addr_t) > 4
         && (ahc->flags & AHC_39BIT_ADDRESSING) != 0)
                len |= (addr >> 8) & AHC_SG_HIGH_ADDR_MASK;

        sg->len = ahc_htole32(len);
        return (consumed);
}

/*
 * Return a string describing the driver.
 */
static const char *
ahc_linux_info(struct Scsi_Host *host)
{
        static char buffer[512];
        char    ahc_info[256];
        char   *bp;
        struct ahc_softc *ahc;

        bp = &buffer[0];
        ahc = *(struct ahc_softc **)host->hostdata;
        memset(bp, 0, sizeof(buffer));
        strcpy(bp, "Adaptec AIC7XXX EISA/VLB/PCI SCSI HBA DRIVER, Rev ");
        strcat(bp, AIC7XXX_DRIVER_VERSION);
        strcat(bp, "\n");
        strcat(bp, "        <");
        strcat(bp, ahc->description);
        strcat(bp, ">\n");
        strcat(bp, "        ");
        ahc_controller_info(ahc, ahc_info);
        strcat(bp, ahc_info);
        strcat(bp, "\n");

        return (bp);
}

/*
 * Queue an SCB to the controller.
 */
static int
ahc_linux_queue(struct scsi_cmnd * cmd, void (*scsi_done) (struct scsi_cmnd *))
{
        struct   ahc_softc *ahc;
        struct   ahc_linux_device *dev = scsi_transport_device_data(cmd->device);

        ahc = *(struct ahc_softc **)cmd->device->host->hostdata;

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

        /*
         * 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 (ahc->platform_data->qfrozen != 0)
                return SCSI_MLQUEUE_HOST_BUSY;

        cmd->result = CAM_REQ_INPROG << 16;

        return ahc_linux_run_command(ahc, dev, cmd);
}

static inline struct scsi_target **
ahc_linux_target_in_softc(struct scsi_target *starget)
{
        struct  ahc_softc *ahc =
                *((struct ahc_softc **)dev_to_shost(&starget->dev)->hostdata);
        unsigned int target_offset;

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

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

static int
ahc_linux_target_alloc(struct scsi_target *starget)
{
        struct  ahc_softc *ahc =
                *((struct ahc_softc **)dev_to_shost(&starget->dev)->hostdata);
        struct seeprom_config *sc = ahc->seep_config;
        unsigned long flags;
        struct scsi_target **ahc_targp = ahc_linux_target_in_softc(starget);
        struct ahc_linux_target *targ = scsi_transport_target_data(starget);
        unsigned short scsirate;
        struct ahc_devinfo devinfo;
        struct ahc_initiator_tinfo *tinfo;
        struct ahc_tmode_tstate *tstate;
        char channel = starget->channel + 'A';
        unsigned int our_id = ahc->our_id;
        unsigned int target_offset;

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

        ahc_lock(ahc, &flags);

        BUG_ON(*ahc_targp != NULL);

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

        if (sc) {
                int maxsync = AHC_SYNCRATE_DT;
                int ultra = 0;
                int flags = sc->device_flags[target_offset];

                if (ahc->flags & AHC_NEWEEPROM_FMT) {
                    if (flags & CFSYNCHISULTRA)
                        ultra = 1;
                } else if (flags & CFULTRAEN)
                        ultra = 1;
                /* AIC nutcase; 10MHz appears as ultra = 1, CFXFER = 0x04
                 * change it to ultra=0, CFXFER = 0 */
                if(ultra && (flags & CFXFER) == 0x04) {
                        ultra = 0;
                        flags &= ~CFXFER;
                }
            
                if ((ahc->features & AHC_ULTRA2) != 0) {
                        scsirate = (flags & CFXFER) | (ultra ? 0x8 : 0);
                } else {
                        scsirate = (flags & CFXFER) << 4;
                        maxsync = ultra ? AHC_SYNCRATE_ULTRA : 
                                AHC_SYNCRATE_FAST;
                }
                spi_max_width(starget) = (flags & CFWIDEB) ? 1 : 0;
                if (!(flags & CFSYNCH))
                        spi_max_offset(starget) = 0;
                spi_min_period(starget) = 
                        ahc_find_period(ahc, scsirate, maxsync);

                tinfo = ahc_fetch_transinfo(ahc, channel, ahc->our_id,
                                            starget->id, &tstate);
        }
        ahc_compile_devinfo(&devinfo, our_id, starget->id,
                            CAM_LUN_WILDCARD, channel,
                            ROLE_INITIATOR);
        ahc_set_syncrate(ahc, &devinfo, NULL, 0, 0, 0,
                         AHC_TRANS_GOAL, /*paused*/FALSE);
        ahc_set_width(ahc, &devinfo, MSG_EXT_WDTR_BUS_8_BIT,
                      AHC_TRANS_GOAL, /*paused*/FALSE);
        ahc_unlock(ahc, &flags);

        return 0;
}

static void
ahc_linux_target_destroy(struct scsi_target *starget)
{
        struct scsi_target **ahc_targp = ahc_linux_target_in_softc(starget);

        *ahc_targp = NULL;
}

static int
ahc_linux_slave_alloc(struct scsi_device *sdev)
{
        struct  ahc_softc *ahc =
                *((struct ahc_softc **)sdev->host->hostdata);
        struct scsi_target *starget = sdev->sdev_target;
        struct ahc_linux_target *targ = scsi_transport_target_data(starget);
        struct ahc_linux_device *dev;

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

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

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

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

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

        return 0;
}

static int
ahc_linux_slave_configure(struct scsi_device *sdev)
{
        struct  ahc_softc *ahc;

        ahc = *((struct ahc_softc **)sdev->host->hostdata);

        if (bootverbose)
                printf("%s: Slave Configure %d\n", ahc_name(ahc), sdev->id);

        ahc_linux_device_queue_depth(sdev);

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

        return 0;
}

static void
ahc_linux_slave_destroy(struct scsi_device *sdev)
{
        struct  ahc_softc *ahc;
        struct  ahc_linux_device *dev = scsi_transport_device_data(sdev);
        struct  ahc_linux_target *targ = scsi_transport_target_data(sdev->sdev_target);

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

        BUG_ON(dev->active);

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

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

        ahc = *((struct ahc_softc **)sdev->host->hostdata);
        channel = sdev->channel;

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

        if (aic7xxx_extended != 0)
                extended = 1;
        else if (channel == 0)
                extended = (ahc->flags & AHC_EXTENDED_TRANS_A) != 0;
        else
                extended = (ahc->flags & AHC_EXTENDED_TRANS_B) != 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
ahc_linux_abort(struct scsi_cmnd *cmd)
{
        int error;

        error = ahc_linux_queue_recovery_cmd(cmd, SCB_ABORT);
        if (error != 0)
                printf("aic7xxx_abort returns 0x%x\n", error);
        return (error);
}

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

        error = ahc_linux_queue_recovery_cmd(cmd, SCB_DEVICE_RESET);
        if (error != 0)
                printf("aic7xxx_dev_reset returns 0x%x\n", error);
        return (error);
}

/*
 * Reset the SCSI bus.
 */
static int
ahc_linux_bus_reset(struct scsi_cmnd *cmd)
{
        struct ahc_softc *ahc;
        int    found;
        unsigned long flags;

        ahc = *(struct ahc_softc **)cmd->device->host->hostdata;

        ahc_lock(ahc, &flags);
        found = ahc_reset_channel(ahc, cmd->device->channel + 'A',
                                  /*initiate reset*/TRUE);
        ahc_unlock(ahc, &flags);

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

        return SUCCESS;
}

struct scsi_host_template aic7xxx_driver_template = {
        .module                 = THIS_MODULE,
        .name                   = "aic7xxx",
        .proc_name              = "aic7xxx",
        .proc_info              = ahc_linux_proc_info,
        .info                   = ahc_linux_info,
        .queuecommand           = ahc_linux_queue,
        .eh_abort_handler       = ahc_linux_abort,
        .eh_device_reset_handler = ahc_linux_dev_reset,
        .eh_bus_reset_handler   = ahc_linux_bus_reset,
#if defined(__i386__)
        .bios_param             = ahc_linux_biosparam,
#endif
        .can_queue              = AHC_MAX_QUEUE,
        .this_id                = -1,
        .cmd_per_lun            = 2,
        .use_clustering         = ENABLE_CLUSTERING,
        .slave_alloc            = ahc_linux_slave_alloc,
        .slave_configure        = ahc_linux_slave_configure,
        .slave_destroy          = ahc_linux_slave_destroy,
        .target_alloc           = ahc_linux_target_alloc,
        .target_destroy         = ahc_linux_target_destroy,
};

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

/******************************** Macros **************************************/
#define BUILD_SCSIID(ahc, cmd)                                              \
        ((((cmd)->device->id << TID_SHIFT) & TID)                           \
        | (((cmd)->device->channel == 0) ? (ahc)->our_id : (ahc)->our_id_b) \
        | (((cmd)->device->channel == 0) ? 0 : TWIN_CHNLB))

/******************************** Bus DMA *************************************/
int
ahc_dma_tag_create(struct ahc_softc *ahc, 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
ahc_dma_tag_destroy(struct ahc_softc *ahc, bus_dma_tag_t dmat)
{
        free(dmat, M_DEVBUF);
}

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

void
ahc_dmamem_free(struct ahc_softc *ahc, bus_dma_tag_t dmat,
                void* vaddr, bus_dmamap_t map)
{
        pci_free_consistent(ahc->dev_softc, dmat->maxsize,
                            vaddr, map);
}

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

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

void
ahc_dmamap_destroy(struct ahc_softc *ahc, bus_dma_tag_t dmat, bus_dmamap_t map)
{
}

int
ahc_dmamap_unload(struct ahc_softc *ahc, bus_dma_tag_t dmat, bus_dmamap_t map)
{
        /* Nothing to do */
        return (0);
}

static void
ahc_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(aic7xxx_tag_info); i++) {
                for (j = 0; j < AHC_NUM_TARGETS; j++) {
                        aic7xxx_tag_info[i].tag_commands[j] = tags;
                }
        }
}

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

        if ((instance >= 0) && (targ >= 0)
         && (instance < NUM_ELEMENTS(aic7xxx_tag_info))
         && (targ < AHC_NUM_TARGETS)) {
                aic7xxx_tag_info[instance].tag_commands[targ] = value & 0xff;
                if (bootverbose)
                        printf("tag_info[%d:%d] = %d\n", instance, targ, value);
        }
}

/*
 * Handle Linux boot parameters. This routine allows for assigning a value
 * to a parameter with a ':' between the parameter and the value.
 * ie. aic7xxx=stpwlev:1,extended
 */
static int
aic7xxx_setup(char *s)
{
        int     i, n;
        char   *p;
        char   *end;

        static struct {
                const char *name;
                uint32_t *flag;
        } options[] = {
                { "extended", &aic7xxx_extended },
                { "no_reset", &aic7xxx_no_reset },
                { "verbose", &aic7xxx_verbose },
                { "allow_memio", &aic7xxx_allow_memio},
#ifdef AHC_DEBUG
                { "debug", &ahc_debug },
#endif
                { "periodic_otag", &aic7xxx_periodic_otag },
                { "pci_parity", &aic7xxx_pci_parity },
                { "seltime", &aic7xxx_seltime },
                { "tag_info", NULL },
                { "global_tag_depth", NULL },
                { "dv", 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) {
                        ahc_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, ahc_linux_setup_tag_info, 0);
                } else if (p[n] == ':') {
                        *(options[i].flag) = simple_strtoul(p + n + 1, NULL, 0);
                } else if (strncmp(p, "verbose", n) == 0) {
                        *(options[i].flag) = 1;
                } else {
                        *(options[i].flag) ^= 0xFFFFFFFF;
                }
        }
        return 1;
}

__setup("aic7xxx=", aic7xxx_setup);

uint32_t aic7xxx_verbose;

int
ahc_linux_register_host(struct ahc_softc *ahc, struct scsi_host_template *template)
{
        char     buf[80];
        struct   Scsi_Host *host;
        char    *new_name;
        u_long   s;

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

        *((struct ahc_softc **)host->hostdata) = ahc;
        ahc_lock(ahc, &s);
        scsi_assign_lock(host, &ahc->platform_data->spin_lock);
        ahc->platform_data->host = host;
        host->can_queue = AHC_MAX_QUEUE;
        host->cmd_per_lun = 2;
        /* XXX No way to communicate the ID for multiple channels */
        host->this_id = ahc->our_id;
        host->irq = ahc->platform_data->irq;
        host->max_id = (ahc->features & AHC_WIDE) ? 16 : 8;
        host->max_lun = AHC_NUM_LUNS;
        host->max_channel = (ahc->features & AHC_TWIN) ? 1 : 0;
        host->sg_tablesize = AHC_NSEG;
        ahc_set_unit(ahc, ahc_linux_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);
                ahc_set_name(ahc, new_name);
        }
        host->unique_id = ahc->unit;
        ahc_linux_initialize_scsi_bus(ahc);
        ahc_intr_enable(ahc, TRUE);
        ahc_unlock(ahc, &s);

        host->transportt = ahc_linux_transport_template;

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

uint64_t
ahc_linux_get_memsize(void)
{
        struct sysinfo si;

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

/*
 * Place the SCSI bus into a known state by either resetting it,
 * or forcing transfer negotiations on the next command to any
 * target.
 */
void
ahc_linux_initialize_scsi_bus(struct ahc_softc *ahc)
{
        int i;
        int numtarg;

        i = 0;
        numtarg = 0;

        if (aic7xxx_no_reset != 0)
                ahc->flags &= ~(AHC_RESET_BUS_A|AHC_RESET_BUS_B);

        if ((ahc->flags & AHC_RESET_BUS_A) != 0)
                ahc_reset_channel(ahc, 'A', /*initiate_reset*/TRUE);
        else
                numtarg = (ahc->features & AHC_WIDE) ? 16 : 8;

        if ((ahc->features & AHC_TWIN) != 0) {

                if ((ahc->flags & AHC_RESET_BUS_B) != 0) {
                        ahc_reset_channel(ahc, 'B', /*initiate_reset*/TRUE);
                } else {
                        if (numtarg == 0)
                                i = 8;
                        numtarg += 8;
                }
        }

        /*
         * Force negotiation to async for all targets that
         * will not see an initial bus reset.
         */
        for (; i < numtarg; i++) {
                struct ahc_devinfo devinfo;
                struct ahc_initiator_tinfo *tinfo;
                struct ahc_tmode_tstate *tstate;
                u_int our_id;
                u_int target_id;
                char channel;

                channel = 'A';
                our_id = ahc->our_id;
                target_id = i;
                if (i > 7 && (ahc->features & AHC_TWIN) != 0) {
                        channel = 'B';
                        our_id = ahc->our_id_b;
                        target_id = i % 8;
                }
                tinfo = ahc_fetch_transinfo(ahc, channel, our_id,
                                            target_id, &tstate);
                ahc_compile_devinfo(&devinfo, our_id, target_id,
                                    CAM_LUN_WILDCARD, channel, ROLE_INITIATOR);
                ahc_update_neg_request(ahc, &devinfo, tstate,
                                       tinfo, AHC_NEG_ALWAYS);
        }
        /* Give the bus some time to recover */
        if ((ahc->flags & (AHC_RESET_BUS_A|AHC_RESET_BUS_B)) != 0) {
                ahc_linux_freeze_simq(ahc);
                init_timer(&ahc->platform_data->reset_timer);
                ahc->platform_data->reset_timer.data = (u_long)ahc;
                ahc->platform_data->reset_timer.expires =
                    jiffies + (AIC7XXX_RESET_DELAY * HZ)/1000;
                ahc->platform_data->reset_timer.function =
                    ahc_linux_release_simq;
                add_timer(&ahc->platform_data->reset_timer);
        }
}

int
ahc_platform_alloc(struct ahc_softc *ahc, void *platform_arg)
{

        ahc->platform_data =
            malloc(sizeof(struct ahc_platform_data), M_DEVBUF, M_NOWAIT);
        if (ahc->platform_data == NULL)
                return (ENOMEM);
        memset(ahc->platform_data, 0, sizeof(struct ahc_platform_data));
        ahc->platform_data->irq = AHC_LINUX_NOIRQ;
        ahc_lockinit(ahc);
        init_MUTEX_LOCKED(&ahc->platform_data->eh_sem);
        ahc->seltime = (aic7xxx_seltime & 0x3) << 4;
        ahc->seltime_b = (aic7xxx_seltime & 0x3) << 4;
        if (aic7xxx_pci_parity == 0)
                ahc->flags |= AHC_DISABLE_PCI_PERR;

        return (0);
}

void
ahc_platform_free(struct ahc_softc *ahc)
{
        struct scsi_target *starget;
        int i, j;

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

                /* destroy all of the device and target objects */
                for (i = 0; i < AHC_NUM_TARGETS; i++) {
                        starget = ahc->platform_data->starget[i];
                        if (starget != NULL) {
                                for (j = 0; j < AHC_NUM_LUNS; j++) {
                                        struct ahc_linux_target *targ =
                                                scsi_transport_target_data(starget);

                                        if (targ->sdev[j] == NULL)
                                                continue;
                                        targ->sdev[j] = NULL;
                                }
                                ahc->platform_data->starget[i] = NULL;
                        }
                }

                if (ahc->platform_data->irq != AHC_LINUX_NOIRQ)
                        free_irq(ahc->platform_data->irq, ahc);
                if (ahc->tag == BUS_SPACE_PIO
                 && ahc->bsh.ioport != 0)
                        release_region(ahc->bsh.ioport, 256);
                if (ahc->tag == BUS_SPACE_MEMIO
                 && ahc->bsh.maddr != NULL) {
                        iounmap(ahc->bsh.maddr);
                        release_mem_region(ahc->platform_data->mem_busaddr,
                                           0x1000);
                }

                free(ahc->platform_data, M_DEVBUF);
        }
}

void
ahc_platform_freeze_devq(struct ahc_softc *ahc, struct scb *scb)
{
        ahc_platform_abort_scbs(ahc, SCB_GET_TARGET(ahc, scb),
                                SCB_GET_CHANNEL(ahc, scb),
                                SCB_GET_LUN(scb), SCB_LIST_NULL,
                                ROLE_UNKNOWN, CAM_REQUEUE_REQ);
}

void
ahc_platform_set_tags(struct ahc_softc *ahc, struct ahc_devinfo *devinfo,
                      ahc_queue_alg alg)
{
        struct scsi_target *starget;
        struct ahc_linux_target *targ;
        struct ahc_linux_device *dev;
        struct scsi_device *sdev;
        u_int target_offset;
        int was_queuing;
        int now_queuing;

        target_offset = devinfo->target;
        if (devinfo->channel != 'A')
                target_offset += 8;
        starget = ahc->platform_data->starget[target_offset];
        targ = scsi_transport_target_data(starget);
        BUG_ON(targ == NULL);
        sdev = targ->sdev[devinfo->lun];
        if (sdev == NULL)
                return;
        dev = scsi_transport_device_data(sdev);

        was_queuing = dev->flags & (AHC_DEV_Q_BASIC|AHC_DEV_Q_TAGGED);
        switch (alg) {
        default:
        case AHC_QUEUE_NONE:
                now_queuing = 0;
                break; 
        case AHC_QUEUE_BASIC:
                now_queuing = AHC_DEV_Q_BASIC;
                break;
        case AHC_QUEUE_TAGGED:
                now_queuing = AHC_DEV_Q_TAGGED;
                break;
        }
        if ((dev->flags & AHC_DEV_FREEZE_TIL_EMPTY) == 0
         && (was_queuing != now_queuing)
         && (dev->active != 0)) {
                dev->flags |= AHC_DEV_FREEZE_TIL_EMPTY;
                dev->qfrozen++;
        }

        dev->flags &= ~(AHC_DEV_Q_BASIC|AHC_DEV_Q_TAGGED|AHC_DEV_PERIODIC_OTAG);
        if (now_queuing) {
                u_int usertags;

                usertags = ahc_linux_user_tagdepth(ahc, 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 == AHC_QUEUE_TAGGED) {
                        dev->flags |= AHC_DEV_Q_TAGGED;
                        if (aic7xxx_periodic_otag != 0)
                                dev->flags |= AHC_DEV_PERIODIC_OTAG;
                } else
                        dev->flags |= AHC_DEV_Q_BASIC;
        } else {
                /* We can only have one opening. */
                dev->maxtags = 0;
                dev->openings =  1 - dev->active;
        }
        switch ((dev->flags & (AHC_DEV_Q_BASIC|AHC_DEV_Q_TAGGED))) {
        case AHC_DEV_Q_BASIC:
                scsi_set_tag_type(sdev, MSG_SIMPLE_TAG);
                scsi_activate_tcq(sdev, dev->openings + dev->active);
                break;
        case AHC_DEV_Q_TAGGED:
                scsi_set_tag_type(sdev, MSG_ORDERED_TAG);
                scsi_activate_tcq(sdev, 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_deactivate_tcq(sdev, 2);
                break;
        }
}

int
ahc_platform_abort_scbs(struct ahc_softc *ahc, int target, char channel,
                        int lun, u_int tag, role_t role, uint32_t status)
{
        return 0;
}

static u_int
ahc_linux_user_tagdepth(struct ahc_softc *ahc, struct ahc_devinfo *devinfo)
{
        static int warned_user;
        u_int tags;

        tags = 0;
        if ((ahc->user_discenable & devinfo->target_mask) != 0) {
                if (ahc->unit >= NUM_ELEMENTS(aic7xxx_tag_info)) {
                        if (warned_user == 0) {

                                printf(KERN_WARNING
"aic7xxx: WARNING: Insufficient tag_info instances\n"
"aic7xxx: for installed controllers. Using defaults\n"
"aic7xxx: Please update the aic7xxx_tag_info array in\n"
"aic7xxx: the aic7xxx_osm..c source file.\n");
                                warned_user++;
                        }
                        tags = AHC_MAX_QUEUE;
                } else {
                        adapter_tag_info_t *tag_info;

                        tag_info = &aic7xxx_tag_info[ahc->unit];
                        tags = tag_info->tag_commands[devinfo->target_offset];
                        if (tags > AHC_MAX_QUEUE)
                                tags = AHC_MAX_QUEUE;
                }
        }
        return (tags);
}

/*
 * Determines the queue depth for a given device.
 */
static void
ahc_linux_device_queue_depth(struct scsi_device *sdev)
{
        struct  ahc_devinfo devinfo;
        u_int   tags;
        struct ahc_softc *ahc = *((struct ahc_softc **)sdev->host->hostdata);

        ahc_compile_devinfo(&devinfo,
                            sdev->sdev_target->channel == 0
                          ? ahc->our_id : ahc->our_id_b,
                            sdev->sdev_target->id, sdev->lun,
                            sdev->sdev_target->channel == 0 ? 'A' : 'B',
                            ROLE_INITIATOR);
        tags = ahc_linux_user_tagdepth(ahc, &devinfo);
        if (tags != 0 && sdev->tagged_supported != 0) {

                ahc_set_tags(ahc, &devinfo, AHC_QUEUE_TAGGED);
                ahc_print_devinfo(ahc, &devinfo);
                printf("Tagged Queuing enabled.  Depth %d\n", tags);
        } else {
                ahc_set_tags(ahc, &devinfo, AHC_QUEUE_NONE);
        }
}

static int
ahc_linux_run_command(struct ahc_softc *ahc, struct ahc_linux_device *dev,
                      struct scsi_cmnd *cmd)
{
        struct   scb *scb;
        struct   hardware_scb *hscb;
        struct   ahc_initiator_tinfo *tinfo;
        struct   ahc_tmode_tstate *tstate;
        uint16_t mask;
        struct scb_tailq *untagged_q = NULL;

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

        /*
         * We only allow one untagged transaction
         * per target in the initiator role unless
         * we are storing a full busy target *lun*
         * table in SCB space.
         */
        if (!blk_rq_tagged(cmd->request)
            && (ahc->features & AHC_SCB_BTT) == 0) {
                int target_offset;

                target_offset = cmd->device->id + cmd->device->channel * 8;
                untagged_q = &(ahc->untagged_queues[target_offset]);
                if (!TAILQ_EMPTY(untagged_q))
                        /* if we're already executing an untagged command
                         * we're busy to another */
                        return SCSI_MLQUEUE_DEVICE_BUSY;
        }

        /*
         * Get an scb to use.
         */
        scb = ahc_get_scb(ahc);
        if (!scb)
                return SCSI_MLQUEUE_HOST_BUSY;

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

        /*
         * Fill out basics of the HSCB.
         */
        hscb->control = 0;
        hscb->scsiid = BUILD_SCSIID(ahc, cmd);
        hscb->lun = cmd->device->lun;
        mask = SCB_GET_TARGET_MASK(ahc, scb);
        tinfo = ahc_fetch_transinfo(ahc, SCB_GET_CHANNEL(ahc, scb),
                                    SCB_GET_OUR_ID(scb),
                                    SCB_GET_TARGET(ahc, scb), &tstate);
        hscb->scsirate = tinfo->scsirate;
        hscb->scsioffset = tinfo->curr.offset;
        if ((tstate->ultraenb & mask) != 0)
                hscb->control |= ULTRAENB;
        
        if ((ahc->user_discenable & mask) != 0)
                hscb->control |= DISCENB;
        
        if ((tstate->auto_negotiate & mask) != 0) {
                scb->flags |= SCB_AUTO_NEGOTIATE;
                scb->hscb->control |= MK_MESSAGE;
        }

        if ((dev->flags & (AHC_DEV_Q_TAGGED|AHC_DEV_Q_BASIC)) != 0) {
                int     msg_bytes;
                uint8_t tag_msgs[2];
                
                msg_bytes = scsi_populate_tag_msg(cmd, tag_msgs);
                if (msg_bytes && tag_msgs[0] != MSG_SIMPLE_TASK) {
                        hscb->control |= tag_msgs[0];
                        if (tag_msgs[0] == MSG_ORDERED_TASK)
                                dev->commands_since_idle_or_otag = 0;
                } else if (dev->commands_since_idle_or_otag == AHC_OTAG_THRESH
                                && (dev->flags & AHC_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;
        if (hscb->cdb_len <= 12) {
                memcpy(hscb->shared_data.cdb, cmd->cmnd, hscb->cdb_len);
        } else {
                memcpy(hscb->cdb32, cmd->cmnd, hscb->cdb_len);
                scb->flags |= SCB_CDB32_PTR;
        }

        scb->platform_data->xfer_len = 0;
        ahc_set_residual(scb, 0);
        ahc_set_sense_residual(scb, 0);
        scb->sg_count = 0;
        if (cmd->use_sg != 0) {
                struct  ahc_dma_seg *sg;
                struct  scatterlist *cur_seg;
                struct  scatterlist *end_seg;
                int     nseg;

                cur_seg = (struct scatterlist *)cmd->request_buffer;
                nseg = pci_map_sg(ahc->dev_softc, cur_seg, cmd->use_sg,
                                  cmd->sc_data_direction);
                end_seg = cur_seg + nseg;
                /* Copy the segments into the SG list. */
                sg = scb->sg_list;
                /*
                 * The sg_count may be larger than nseg if
                 * a transfer crosses a 32bit page.
                 */ 
                while (cur_seg < end_seg) {
                        dma_addr_t addr;
                        bus_size_t len;
                        int consumed;

                        addr = sg_dma_address(cur_seg);
                        len = sg_dma_len(cur_seg);
                        consumed = ahc_linux_map_seg(ahc, scb,
                                                     sg, addr, len);
                        sg += consumed;
                        scb->sg_count += consumed;
                        cur_seg++;
                }
                sg--;
                sg->len |= ahc_htole32(AHC_DMA_LAST_SEG);

                /*
                 * Reset the sg list pointer.
                 */
                scb->hscb->sgptr =
                        ahc_htole32(scb->sg_list_phys | SG_FULL_RESID);
                
                /*
                 * Copy the first SG into the "current"
                 * data pointer area.
                 */
                scb->hscb->dataptr = scb->sg_list->addr;
                scb->hscb->datacnt = scb->sg_list->len;
        } else if (cmd->request_bufflen != 0) {
                struct   ahc_dma_seg *sg;
                dma_addr_t addr;

                sg = scb->sg_list;
                addr = pci_map_single(ahc->dev_softc,
                                      cmd->request_buffer,
                                      cmd->request_bufflen,
                                      cmd->sc_data_direction);
                scb->platform_data->buf_busaddr = addr;
                scb->sg_count = ahc_linux_map_seg(ahc, scb,
                                                  sg, addr,
                                                  cmd->request_bufflen);
                sg->len |= ahc_htole32(AHC_DMA_LAST_SEG);

                /*
                 * Reset the sg list pointer.
                 */
                scb->hscb->sgptr =
                        ahc_htole32(scb->sg_list_phys | SG_FULL_RESID);

                /*
                 * Copy the first SG into the "current"
                 * data pointer area.
                 */
                scb->hscb->dataptr = sg->addr;
                scb->hscb->datacnt = sg->len;
        } else {
                scb->hscb->sgptr = ahc_htole32(SG_LIST_NULL);
                scb->hscb->dataptr = 0;
                scb->hscb->datacnt = 0;
                scb->sg_count = 0;
        }

        LIST_INSERT_HEAD(&ahc->pending_scbs, scb, pending_links);
        dev->openings--;
        dev->active++;
        dev->commands_issued++;
        if ((dev->flags & AHC_DEV_PERIODIC_OTAG) != 0)
                dev->commands_since_idle_or_otag++;
        
        scb->flags |= SCB_ACTIVE;
        if (untagged_q) {
                TAILQ_INSERT_TAIL(untagged_q, scb, links.tqe);
                scb->flags |= SCB_UNTAGGEDQ;
        }
        ahc_queue_scb(ahc, scb);
        return 0;
}

/*
 * SCSI controller interrupt handler.
 */
irqreturn_t
ahc_linux_isr(int irq, void *dev_id, struct pt_regs * regs)
{
        struct  ahc_softc *ahc;
        u_long  flags;
        int     ours;

        ahc = (struct ahc_softc *) dev_id;
        ahc_lock(ahc, &flags); 
        ours = ahc_intr(ahc);
        ahc_unlock(ahc, &flags);
        return IRQ_RETVAL(ours);
}

void
ahc_platform_flushwork(struct ahc_softc *ahc)
{

}

void
ahc_send_async(struct ahc_softc *ahc, char channel,
               u_int target, u_int lun, ac_code code, void *arg)
{
        switch (code) {
        case AC_TRANSFER_NEG:
        {
                char    buf[80];
                struct  scsi_target *starget;
                struct  ahc_linux_target *targ;
                struct  info_str info;
                struct  ahc_initiator_tinfo *tinfo;
                struct  ahc_tmode_tstate *tstate;
                int     target_offset;
                unsigned int target_ppr_options;

                BUG_ON(target == CAM_TARGET_WILDCARD);

                info.buffer = buf;
                info.length = sizeof(buf);
                info.offset = 0;
                info.pos = 0;
                tinfo = ahc_fetch_transinfo(ahc, channel,
                                                channel == 'A' ? ahc->our_id
                                                               : ahc->our_id_b,
                                                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.
                 */
                target_offset = target;
                if (channel == 'B')
                        target_offset += 8;
                starget = ahc->platform_data->starget[target_offset];
                targ = scsi_transport_target_data(starget);
                if (targ == NULL)
                        break;

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

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

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

/*
 * Calls the higher level scsi done function and frees the scb.
 */
void
ahc_done(struct ahc_softc *ahc, struct scb *scb)
{
        struct scsi_cmnd *cmd;
        struct     ahc_linux_device *dev;

        LIST_REMOVE(scb, pending_links);
        if ((scb->flags & SCB_UNTAGGEDQ) != 0) {
                struct scb_tailq *untagged_q;
                int target_offset;

                target_offset = SCB_GET_TARGET_OFFSET(ahc, scb);
                untagged_q = &(ahc->untagged_queues[target_offset]);
                TAILQ_REMOVE(untagged_q, scb, links.tqe);
                BUG_ON(!TAILQ_EMPTY(untagged_q));
        }

        if ((scb->flags & SCB_ACTIVE) == 0) {
                printf("SCB %d done'd twice\n", scb->hscb->tag);
                ahc_dump_card_state(ahc);
                panic("Stopping for safety");
        }
        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--;
        }
        ahc_linux_unmap_scb(ahc, 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 (ahc_get_transaction_status(scb) == CAM_REQ_INPROG) {
                uint32_t amount_xferred;

                amount_xferred =
                    ahc_get_transfer_length(scb) - ahc_get_residual(scb);
                if ((scb->flags & SCB_TRANSMISSION_ERROR) != 0) {
#ifdef AHC_DEBUG
                        if ((ahc_debug & AHC_SHOW_MISC) != 0) {
                                ahc_print_path(ahc, scb);
                                printf("Set CAM_UNCOR_PARITY\n");
                        }
#endif
                        ahc_set_transaction_status(scb, CAM_UNCOR_PARITY);
#ifdef AHC_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;

                        ahc_print_path(ahc, scb);
                        printf("CDB:");
                        for (i = 0; i < scb->io_ctx->cmd_len; i++)
                                printf(" 0x%x", scb->io_ctx->cmnd[i]);
                        printf("\n");
                        ahc_print_path(ahc, scb);
                        printf("Saw underflow (%ld of %ld bytes). "
                               "Treated as error\n",
                                ahc_get_residual(scb),
                                ahc_get_transfer_length(scb));
                        ahc_set_transaction_status(scb, CAM_DATA_RUN_ERR);
#endif
                } else {
                        ahc_set_transaction_status(scb, CAM_REQ_CMP);
                }
        } else if (ahc_get_transaction_status(scb) == CAM_SCSI_STATUS_ERROR) {
                ahc_linux_handle_scsi_status(ahc, cmd->device, scb);
        }

        if (dev->openings == 1
         && ahc_get_transaction_status(scb) == CAM_REQ_CMP
         && ahc_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 > AHC_TAG_SUCCESS_INTERVAL) {
                dev->tag_success_count = 0;
                dev->openings++;
        }

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

        if ((scb->flags & SCB_RECOVERY_SCB) != 0) {
                printf("Recovery SCB completes\n");
                if (ahc_get_transaction_status(scb) == CAM_BDR_SENT
                 || ahc_get_transaction_status(scb) == CAM_REQ_ABORTED)
                        ahc_set_transaction_status(scb, CAM_CMD_TIMEOUT);
                if ((ahc->platform_data->flags & AHC_UP_EH_SEMAPHORE) != 0) {
                        ahc->platform_data->flags &= ~AHC_UP_EH_SEMAPHORE;
                        up(&ahc->platform_data->eh_sem);
                }
        }

        ahc_free_scb(ahc, scb);
        ahc_linux_queue_cmd_complete(ahc, cmd);
}

static void
ahc_linux_handle_scsi_status(struct ahc_softc *ahc,
                             struct scsi_device *sdev, struct scb *scb)
{
        struct  ahc_devinfo devinfo;
        struct ahc_linux_device *dev = scsi_transport_device_data(sdev);

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

                /*
                 * Copy sense information to the OS's cmd
                 * structure if it is available.
                 */
                cmd = scb->io_ctx;
                if (scb->flags & SCB_SENSE) {
                        u_int sense_size;

                        sense_size = MIN(sizeof(struct scsi_sense_data)
                                       - ahc_get_sense_residual(scb),
                                         sizeof(cmd->sense_buffer));
                        memcpy(cmd->sense_buffer,
                               ahc_get_sense_buf(ahc, scb), sense_size);
                        if (sense_size < sizeof(cmd->sense_buffer))
                                memset(&cmd->sense_buffer[sense_size], 0,
                                       sizeof(cmd->sense_buffer) - sense_size);
                        cmd->result |= (DRIVER_SENSE << 24);
#ifdef AHC_DEBUG
                        if (ahc_debug & AHC_SHOW_SENSE) {
                                int i;

                                printf("Copied %d bytes of sense data:",
                                       sense_size);
                                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;
/*
                        ahc_print_path(ahc, scb);
                        printf("Dropping tag count to %d\n", dev->active);
 */
                        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
                                 == AHC_LOCK_TAGS_COUNT) {
                                        dev->maxtags = dev->active;
                                        ahc_print_path(ahc, 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;
                        }
                        ahc_set_transaction_status(scb, CAM_REQUEUE_REQ);
                        ahc_set_scsi_status(scb, SCSI_STATUS_OK);
                        ahc_platform_set_tags(ahc, &devinfo,
                                     (dev->flags & AHC_DEV_Q_BASIC)
                                   ? AHC_QUEUE_BASIC : AHC_QUEUE_TAGGED);
                        break;
                }
                /*
                 * Drop down to a single opening, and treat this
                 * as if the target returned BUSY SCSI status.
                 */
                dev->openings = 1;
                ahc_set_scsi_status(scb, SCSI_STATUS_BUSY);
                ahc_platform_set_tags(ahc, &devinfo,
                             (dev->flags & AHC_DEV_Q_BASIC)
                           ? AHC_QUEUE_BASIC : AHC_QUEUE_TAGGED);
                break;
        }
        }
}

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

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

                ahc_cmd_set_transaction_status(cmd, new_status);
        }

        cmd->scsi_done(cmd);
}

static void
ahc_linux_sem_timeout(u_long arg)
{
        struct  ahc_softc *ahc;
        u_long  s;

        ahc = (struct ahc_softc *)arg;

        ahc_lock(ahc, &s);
        if ((ahc->platform_data->flags & AHC_UP_EH_SEMAPHORE) != 0) {
                ahc->platform_data->flags &= ~AHC_UP_EH_SEMAPHORE;
                up(&ahc->platform_data->eh_sem);
        }
        ahc_unlock(ahc, &s);
}

static void
ahc_linux_freeze_simq(struct ahc_softc *ahc)
{
        ahc->platform_data->qfrozen++;
        if (ahc->platform_data->qfrozen == 1) {
                scsi_block_requests(ahc->platform_data->host);

                /* XXX What about Twin channels? */
                ahc_platform_abort_scbs(ahc, CAM_TARGET_WILDCARD, ALL_CHANNELS,
                                        CAM_LUN_WILDCARD, SCB_LIST_NULL,
                                        ROLE_INITIATOR, CAM_REQUEUE_REQ);
        }
}

static void
ahc_linux_release_simq(u_long arg)
{
        struct ahc_softc *ahc;
        u_long s;
        int    unblock_reqs;

        ahc = (struct ahc_softc *)arg;

        unblock_reqs = 0;
        ahc_lock(ahc, &s);
        if (ahc->platform_data->qfrozen > 0)
                ahc->platform_data->qfrozen--;
        if (ahc->platform_data->qfrozen == 0)
                unblock_reqs = 1;
        ahc_unlock(ahc, &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(ahc->platform_data->host);
}

static int
ahc_linux_queue_recovery_cmd(struct scsi_cmnd *cmd, scb_flag flag)
{
        struct ahc_softc *ahc;
        struct ahc_linux_device *dev;
        struct scb *pending_scb;
        u_int  saved_scbptr;
        u_int  active_scb_index;
        u_int  last_phase;
        u_int  saved_scsiid;
        u_int  cdb_byte;
        int    retval;
        int    was_paused;
        int    paused;
        int    wait;
        int    disconnected;

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

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

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

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

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

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

        if ((dev->flags & (AHC_DEV_Q_BASIC|AHC_DEV_Q_TAGGED)) == 0
         && ahc_search_untagged_queues(ahc, cmd, cmd->device->id,
                                       cmd->device->channel + 'A',
                                       cmd->device->lun,
                                       CAM_REQ_ABORTED, SEARCH_COMPLETE) != 0) {
                printf("%s:%d:%d:%d: Command found on untagged queue\n",
                       ahc_name(ahc), cmd->device->channel, cmd->device->id,
                       cmd->device->lun);
                retval = SUCCESS;
                goto done;
        }

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

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

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

        if (pending_scb == NULL) {
                printf("%s:%d:%d:%d: Command not found\n",
                       ahc_name(ahc), 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 and that we didn't "just" miss
         * an interrupt that would affect this cmd.
         */
        was_paused = ahc_is_paused(ahc);
        ahc_pause_and_flushwork(ahc);
        paused = TRUE;

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

        printf("%s: At time of recovery, card was %spaused\n",
               ahc_name(ahc), was_paused ? "" : "not ");
        ahc_dump_card_state(ahc);

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

        if (disconnected && (ahc_inb(ahc, SEQ_FLAGS) & NOT_IDENTIFIED) == 0) {
                struct scb *bus_scb;

                bus_scb = ahc_lookup_scb(ahc, ahc_inb(ahc, SCB_TAG));
                if (bus_scb == pending_scb)
                        disconnected = FALSE;
                else if (flag != SCB_ABORT
                      && ahc_inb(ahc, SAVED_SCSIID) == pending_scb->hscb->scsiid
                      && ahc_inb(ahc, SAVED_LUN) == SCB_GET_LUN(pending_scb))
                        disconnected = FALSE;
        }

        /*
         * At this point, pending_scb is the scb associated with the
         * passed in command.  That command is currently active on the
         * bus, is in the disconnected state, or we're hoping to find
         * a command for the same target active on the bus to abuse to
         * send a BDR.  Queue the appropriate message based on which of
         * these states we are in.
         */
        last_phase = ahc_inb(ahc, LASTPHASE);
        saved_scbptr = ahc_inb(ahc, SCBPTR);
        active_scb_index = ahc_inb(ahc, SCB_TAG);
        saved_scsiid = ahc_inb(ahc, SAVED_SCSIID);
        if (last_phase != P_BUSFREE
         && (pending_scb->hscb->tag == active_scb_index
          || (flag == SCB_DEVICE_RESET
           && SCSIID_TARGET(ahc, saved_scsiid) == cmd->device->id))) {

                /*
                 * We're active on the bus, so assert ATN
                 * and hope that the target responds.
                 */
                pending_scb = ahc_lookup_scb(ahc, active_scb_index);
                pending_scb->flags |= SCB_RECOVERY_SCB|flag;
                ahc_outb(ahc, MSG_OUT, HOST_MSG);
                ahc_outb(ahc, SCSISIGO, last_phase|ATNO);
                printf("%s:%d:%d:%d: Device is active, asserting ATN\n",
                       ahc_name(ahc), 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.
                 * In either case (selection or reselection),
                 * we will now issue the approprate message
                 * to the timed-out device.
                 *
                 * Set the MK_MESSAGE control bit indicating
                 * that we desire to send a message.  We
                 * also set the disconnected flag since
                 * in the paging case 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;
                pending_scb->flags |= SCB_RECOVERY_SCB|flag;

                /*
                 * Remove any cached copy of this SCB in the
                 * disconnected list in preparation for the
                 * queuing of our abort SCB.  We use the
                 * same element in the SCB, SCB_NEXT, for
                 * both the qinfifo and the disconnected list.
                 */
                ahc_search_disc_list(ahc, cmd->device->id,
                                     cmd->device->channel + 'A',
                                     cmd->device->lun, pending_scb->hscb->tag,
                                     /*stop_on_first*/TRUE,
                                     /*remove*/TRUE,
                                     /*save_state*/FALSE);

                /*
                 * In the non-paging case, 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.
                 */
                if ((ahc->flags & AHC_PAGESCBS) == 0) {
                        ahc_outb(ahc, SCBPTR, pending_scb->hscb->tag);
                        ahc_outb(ahc, SCB_CONTROL,
                                 ahc_inb(ahc, SCB_CONTROL)|MK_MESSAGE);
                }

                /*
                 * Clear out any entries in the QINFIFO first
                 * so we are the next SCB for this target
                 * to run.
                 */
                ahc_search_qinfifo(ahc, cmd->device->id,
                                   cmd->device->channel + 'A',
                                   cmd->device->lun, SCB_LIST_NULL,
                                   ROLE_INITIATOR, CAM_REQUEUE_REQ,
                                   SEARCH_COMPLETE);
                ahc_qinfifo_requeue_tail(ahc, pending_scb);
                ahc_outb(ahc, SCBPTR, saved_scbptr);
                ahc_print_path(ahc, pending_scb);
                printf("Device is disconnected, re-queuing SCB\n");
                wait = TRUE;
        } else {
                printf("%s:%d:%d:%d: Unable to deliver message\n",
                       ahc_name(ahc), 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)
                ahc_unpause(ahc);
        if (wait) {
                struct timer_list timer;
                int ret;

                ahc->platform_data->flags |= AHC_UP_EH_SEMAPHORE;
                spin_unlock_irq(&ahc->platform_data->spin_lock);
                init_timer(&timer);
                timer.data = (u_long)ahc;
                timer.expires = jiffies + (5 * HZ);
                timer.function = ahc_linux_sem_timeout;
                add_timer(&timer);
                printf("Recovery code sleeping\n");
                down(&ahc->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(&ahc->platform_data->spin_lock);
        }

        spin_unlock_irq(&ahc->platform_data->spin_lock);
        return (retval);
}

void
ahc_platform_dump_card_state(struct ahc_softc *ahc)
{
}

static void ahc_linux_exit(void);

static void ahc_linux_set_width(struct scsi_target *starget, int width)
{
        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
        struct ahc_softc *ahc = *((struct ahc_softc **)shost->hostdata);
        struct ahc_devinfo devinfo;
        unsigned long flags;

        ahc_compile_devinfo(&devinfo, shost->this_id, starget->id, 0,
                            starget->channel + 'A', ROLE_INITIATOR);
        ahc_lock(ahc, &flags);
        ahc_set_width(ahc, &devinfo, width, AHC_TRANS_GOAL, FALSE);
        ahc_unlock(ahc, &flags);
}

static void ahc_linux_set_period(struct scsi_target *starget, int period)
{
        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
        struct ahc_softc *ahc = *((struct ahc_softc **)shost->hostdata);
        struct ahc_tmode_tstate *tstate;
        struct ahc_initiator_tinfo *tinfo 
                = ahc_fetch_transinfo(ahc,
                                      starget->channel + 'A',
                                      shost->this_id, starget->id, &tstate);
        struct ahc_devinfo devinfo;
        unsigned int ppr_options = tinfo->goal.ppr_options;
        unsigned long flags;
        unsigned long offset = tinfo->goal.offset;
        struct ahc_syncrate *syncrate;

        if (offset == 0)
                offset = MAX_OFFSET;

        if (period < 9)
                period = 9;     /* 12.5ns is our minimum */
        if (period == 9)
                ppr_options |= MSG_EXT_PPR_DT_REQ;

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

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

        syncrate = ahc_find_syncrate(ahc, &period, &ppr_options, AHC_SYNCRATE_DT);
        ahc_lock(ahc, &flags);
        ahc_set_syncrate(ahc, &devinfo, syncrate, period, offset,
                         ppr_options, AHC_TRANS_GOAL, FALSE);
        ahc_unlock(ahc, &flags);
}

static void ahc_linux_set_offset(struct scsi_target *starget, int offset)
{
        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
        struct ahc_softc *ahc = *((struct ahc_softc **)shost->hostdata);
        struct ahc_tmode_tstate *tstate;
        struct ahc_initiator_tinfo *tinfo 
                = ahc_fetch_transinfo(ahc,
                                      starget->channel + 'A',
                                      shost->this_id, starget->id, &tstate);
        struct ahc_devinfo devinfo;
        unsigned int ppr_options = 0;
        unsigned int period = 0;
        unsigned long flags;
        struct ahc_syncrate *syncrate = NULL;

        ahc_compile_devinfo(&devinfo, shost->this_id, starget->id, 0,
                            starget->channel + 'A', ROLE_INITIATOR);
        if (offset != 0) {
                syncrate = ahc_find_syncrate(ahc, &period, &ppr_options, AHC_SYNCRATE_DT);
                period = tinfo->goal.period;
                ppr_options = tinfo->goal.ppr_options;
        }
        ahc_lock(ahc, &flags);
        ahc_set_syncrate(ahc, &devinfo, syncrate, period, offset,
                         ppr_options, AHC_TRANS_GOAL, FALSE);
        ahc_unlock(ahc, &flags);
}

static void ahc_linux_set_dt(struct scsi_target *starget, int dt)
{
        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
        struct ahc_softc *ahc = *((struct ahc_softc **)shost->hostdata);
        struct ahc_tmode_tstate *tstate;
        struct ahc_initiator_tinfo *tinfo 
                = ahc_fetch_transinfo(ahc,
                                      starget->channel + 'A',
                                      shost->this_id, starget->id, &tstate);
        struct ahc_devinfo devinfo;
        unsigned int ppr_options = tinfo->goal.ppr_options
                & ~MSG_EXT_PPR_DT_REQ;
        unsigned int period = tinfo->goal.period;
        unsigned int width = tinfo->goal.width;
        unsigned long flags;
        struct ahc_syncrate *syncrate;

        if (dt) {
                ppr_options |= MSG_EXT_PPR_DT_REQ;
                if (!width)
                        ahc_linux_set_width(starget, 1);
        } else if (period == 9)
                period = 10;    /* if resetting DT, period must be >= 25ns */

        ahc_compile_devinfo(&devinfo, shost->this_id, starget->id, 0,
                            starget->channel + 'A', ROLE_INITIATOR);
        syncrate = ahc_find_syncrate(ahc, &period, &ppr_options,AHC_SYNCRATE_DT);
        ahc_lock(ahc, &flags);
        ahc_set_syncrate(ahc, &devinfo, syncrate, period, tinfo->goal.offset,
                         ppr_options, AHC_TRANS_GOAL, FALSE);
        ahc_unlock(ahc, &flags);
}

#if 0
/* FIXME: This code claims to support IU and QAS.  However, the actual
 * sequencer code and aic7xxx_core have no support for these parameters and
 * will get into a bad state if they're negotiated.  Do not enable this
 * unless you know what you're doing */
static void ahc_linux_set_qas(struct scsi_target *starget, int qas)
{
        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
        struct ahc_softc *ahc = *((struct ahc_softc **)shost->hostdata);
        struct ahc_tmode_tstate *tstate;
        struct ahc_initiator_tinfo *tinfo 
                = ahc_fetch_transinfo(ahc,
                                      starget->channel + 'A',
                                      shost->this_id, starget->id, &tstate);
        struct ahc_devinfo devinfo;
        unsigned int ppr_options = tinfo->goal.ppr_options
                & ~MSG_EXT_PPR_QAS_REQ;
        unsigned int period = tinfo->goal.period;
        unsigned long flags;
        struct ahc_syncrate *syncrate;

        if (qas)
                ppr_options |= MSG_EXT_PPR_QAS_REQ;

        ahc_compile_devinfo(&devinfo, shost->this_id, starget->id, 0,
                            starget->channel + 'A', ROLE_INITIATOR);
        syncrate = ahc_find_syncrate(ahc, &period, &ppr_options, AHC_SYNCRATE_DT);
        ahc_lock(ahc, &flags);
        ahc_set_syncrate(ahc, &devinfo, syncrate, period, tinfo->goal.offset,
                         ppr_options, AHC_TRANS_GOAL, FALSE);
        ahc_unlock(ahc, &flags);
}

static void ahc_linux_set_iu(struct scsi_target *starget, int iu)
{
        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
        struct ahc_softc *ahc = *((struct ahc_softc **)shost->hostdata);
        struct ahc_tmode_tstate *tstate;
        struct ahc_initiator_tinfo *tinfo 
                = ahc_fetch_transinfo(ahc,
                                      starget->channel + 'A',
                                      shost->this_id, starget->id, &tstate);
        struct ahc_devinfo devinfo;
        unsigned int ppr_options = tinfo->goal.ppr_options
                & ~MSG_EXT_PPR_IU_REQ;
        unsigned int period = tinfo->goal.period;
        unsigned long flags;
        struct ahc_syncrate *syncrate;

        if (iu)
                ppr_options |= MSG_EXT_PPR_IU_REQ;

        ahc_compile_devinfo(&devinfo, shost->this_id, starget->id, 0,
                            starget->channel + 'A', ROLE_INITIATOR);
        syncrate = ahc_find_syncrate(ahc, &period, &ppr_options, AHC_SYNCRATE_DT);
        ahc_lock(ahc, &flags);
        ahc_set_syncrate(ahc, &devinfo, syncrate, period, tinfo->goal.offset,
                         ppr_options, AHC_TRANS_GOAL, FALSE);
        ahc_unlock(ahc, &flags);
}
#endif

static struct spi_function_template ahc_linux_transport_functions = {
        .set_offset     = ahc_linux_set_offset,
        .show_offset    = 1,
        .set_period     = ahc_linux_set_period,
        .show_period    = 1,
        .set_width      = ahc_linux_set_width,
        .show_width     = 1,
        .set_dt         = ahc_linux_set_dt,
        .show_dt        = 1,
#if 0
        .set_iu         = ahc_linux_set_iu,
        .show_iu        = 1,
        .set_qas        = ahc_linux_set_qas,
        .show_qas       = 1,
#endif
};



static int __init
ahc_linux_init(void)
{
        /*
         * If we've been passed any parameters, process them now.
         */
        if (aic7xxx)
                aic7xxx_setup(aic7xxx);

        ahc_linux_transport_template =
                spi_attach_transport(&ahc_linux_transport_functions);
        if (!ahc_linux_transport_template)
                return -ENODEV;

        scsi_transport_reserve_target(ahc_linux_transport_template,
                                      sizeof(struct ahc_linux_target));
        scsi_transport_reserve_device(ahc_linux_transport_template,
                                      sizeof(struct ahc_linux_device));

        ahc_linux_pci_init();
        ahc_linux_eisa_init();
        return 0;
}

static void
ahc_linux_exit(void)
{
        ahc_linux_pci_exit();
        ahc_linux_eisa_exit();
        spi_release_transport(ahc_linux_transport_template);
}

module_init(ahc_linux_init);
module_exit(ahc_linux_exit);