sym_glue.c

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/*
 * Device driver for the SYMBIOS/LSILOGIC 53C8XX and 53C1010 family 
 * of PCI-SCSI IO processors.
 *
 * Copyright (C) 1999-2001  Gerard Roudier <[email protected]>
 * Copyright (c) 2003-2005  Matthew Wilcox <[email protected]>
 *
 * This driver is derived from the Linux sym53c8xx driver.
 * Copyright (C) 1998-2000  Gerard Roudier
 *
 * The sym53c8xx driver is derived from the ncr53c8xx driver that had been 
 * a port of the FreeBSD ncr driver to Linux-1.2.13.
 *
 * The original ncr driver has been written for 386bsd and FreeBSD by
 *         Wolfgang Stanglmeier        <[email protected]>
 *         Stefan Esser                <[email protected]>
 * Copyright (C) 1994  Wolfgang Stanglmeier
 *
 * Other major contributions:
 *
 * NVRAM detection and reading.
 * Copyright (C) 1997 Richard Waltham <[email protected]>
 *
 *-----------------------------------------------------------------------------
 *
 * 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 of the License, 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; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#include <linux/ctype.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/spinlock.h>
#include <scsi/scsi.h>
#include <scsi/scsi_tcq.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_transport.h>

#include "sym_glue.h"
#include "sym_nvram.h"

#define NAME53C     "sym53c"
#define NAME53C8XX  "sym53c8xx"

struct sym_driver_setup sym_driver_setup = SYM_LINUX_DRIVER_SETUP;
unsigned int sym_debug_flags = 0;

static char *excl_string;
static char *safe_string;
module_param_named(cmd_per_lun, sym_driver_setup.max_tag, ushort, 0);
module_param_named(burst, sym_driver_setup.burst_order, byte, 0);
module_param_named(led, sym_driver_setup.scsi_led, byte, 0);
module_param_named(diff, sym_driver_setup.scsi_diff, byte, 0);
module_param_named(irqm, sym_driver_setup.irq_mode, byte, 0);
module_param_named(buschk, sym_driver_setup.scsi_bus_check, byte, 0);
module_param_named(hostid, sym_driver_setup.host_id, byte, 0);
module_param_named(verb, sym_driver_setup.verbose, byte, 0);
module_param_named(debug, sym_debug_flags, uint, 0);
module_param_named(settle, sym_driver_setup.settle_delay, byte, 0);
module_param_named(nvram, sym_driver_setup.use_nvram, byte, 0);
module_param_named(excl, excl_string, charp, 0);
module_param_named(safe, safe_string, charp, 0);

MODULE_PARM_DESC(cmd_per_lun, "The maximum number of tags to use by default");
MODULE_PARM_DESC(burst, "Maximum burst.  0 to disable, 255 to read from registers");
MODULE_PARM_DESC(led, "Set to 1 to enable LED support");
MODULE_PARM_DESC(diff, "0 for no differential mode, 1 for BIOS, 2 for always, 3 for not GPIO3");
MODULE_PARM_DESC(irqm, "0 for open drain, 1 to leave alone, 2 for totem pole");
MODULE_PARM_DESC(buschk, "0 to not check, 1 for detach on error, 2 for warn on error");
MODULE_PARM_DESC(hostid, "The SCSI ID to use for the host adapters");
MODULE_PARM_DESC(verb, "0 for minimal verbosity, 1 for normal, 2 for excessive");
MODULE_PARM_DESC(debug, "Set bits to enable debugging");
MODULE_PARM_DESC(settle, "Settle delay in seconds.  Default 3");
MODULE_PARM_DESC(nvram, "Option currently not used");
MODULE_PARM_DESC(excl, "List ioport addresses here to prevent controllers from being attached");
MODULE_PARM_DESC(safe, "Set other settings to a \"safe mode\"");

MODULE_LICENSE("GPL");
MODULE_VERSION(SYM_VERSION);
MODULE_AUTHOR("Matthew Wilcox <[email protected]>");
MODULE_DESCRIPTION("NCR, Symbios and LSI 8xx and 1010 PCI SCSI adapters");

static void sym2_setup_params(void)
{
    char *p = excl_string;
    int xi = 0;

    while (p && (xi < 8)) {
        char *next_p;
        int val = (int) simple_strtoul(p, &next_p, 0);
        sym_driver_setup.excludes[xi++] = val;
        p = next_p;
    }

    if (safe_string) {
        if (*safe_string == 'y') {
            sym_driver_setup.max_tag = 0;
            sym_driver_setup.burst_order = 0;
            sym_driver_setup.scsi_led = 0;
            sym_driver_setup.scsi_diff = 1;
            sym_driver_setup.irq_mode = 0;
            sym_driver_setup.scsi_bus_check = 2;
            sym_driver_setup.host_id = 7;
            sym_driver_setup.verbose = 2;
            sym_driver_setup.settle_delay = 10;
            sym_driver_setup.use_nvram = 1;
        } else if (*safe_string != 'n') {
            printk(KERN_WARNING NAME53C8XX "Ignoring parameter %s"
                    " passed to safe option", safe_string);
        }
    }
}

static struct scsi_transport_template *sym2_transport_template = NULL;

/*
 *  Driver private area in the SCSI command structure.
 */
struct sym_ucmd {       /* Override the SCSI pointer structure */
    struct completion *eh_done;     /* SCSI error handling */
};

#define SYM_UCMD_PTR(cmd)  ((struct sym_ucmd *)(&(cmd)->SCp))
#define SYM_SOFTC_PTR(cmd) sym_get_hcb(cmd->device->host)

/*
 *  Complete a pending CAM CCB.
 */
void sym_xpt_done(struct sym_hcb *np, struct scsi_cmnd *cmd)
{
    struct sym_ucmd *ucmd = SYM_UCMD_PTR(cmd);
    BUILD_BUG_ON(sizeof(struct scsi_pointer) < sizeof(struct sym_ucmd));

    if (ucmd->eh_done)
        complete(ucmd->eh_done);

    scsi_dma_unmap(cmd);
    cmd->scsi_done(cmd);
}

/*
 *  Tell the SCSI layer about a BUS RESET.
 */
void sym_xpt_async_bus_reset(struct sym_hcb *np)
{
    printf_notice("%s: SCSI BUS has been reset.\n", sym_name(np));
    np->s.settle_time = jiffies + sym_driver_setup.settle_delay * HZ;
    np->s.settle_time_valid = 1;
    if (sym_verbose >= 2)
        printf_info("%s: command processing suspended for %d seconds\n",
                sym_name(np), sym_driver_setup.settle_delay);
}

/*
 *  Choose the more appropriate CAM status if 
 *  the IO encountered an extended error.
 */
static int sym_xerr_cam_status(int cam_status, int x_status)
{
    if (x_status) {
        if  (x_status & XE_PARITY_ERR)
            cam_status = DID_PARITY;
        else if (x_status &(XE_EXTRA_DATA|XE_SODL_UNRUN|XE_SWIDE_OVRUN))
            cam_status = DID_ERROR;
        else if (x_status & XE_BAD_PHASE)
            cam_status = DID_ERROR;
        else
            cam_status = DID_ERROR;
    }
    return cam_status;
}

/*
 *  Build CAM result for a failed or auto-sensed IO.
 */
void sym_set_cam_result_error(struct sym_hcb *np, struct sym_ccb *cp, int resid)
{
    struct scsi_cmnd *cmd = cp->cmd;
    u_int cam_status, scsi_status, drv_status;

    drv_status  = 0;
    cam_status  = DID_OK;
    scsi_status = cp->ssss_status;

    if (cp->host_flags & HF_SENSE) {
        scsi_status = cp->sv_scsi_status;
        resid = cp->sv_resid;
        if (sym_verbose && cp->sv_xerr_status)
            sym_print_xerr(cmd, cp->sv_xerr_status);
        if (cp->host_status == HS_COMPLETE &&
            cp->ssss_status == S_GOOD &&
            cp->xerr_status == 0) {
            cam_status = sym_xerr_cam_status(DID_OK,
                             cp->sv_xerr_status);
            drv_status = DRIVER_SENSE;
            /*
             *  Bounce back the sense data to user.
             */
            memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
            memcpy(cmd->sense_buffer, cp->sns_bbuf,
                   min(SCSI_SENSE_BUFFERSIZE, SYM_SNS_BBUF_LEN));
#if 0
            /*
             *  If the device reports a UNIT ATTENTION condition 
             *  due to a RESET condition, we should consider all 
             *  disconnect CCBs for this unit as aborted.
             */
            if (1) {
                u_char *p;
                p  = (u_char *) cmd->sense_data;
                if (p[0]==0x70 && p[2]==0x6 && p[12]==0x29)
                    sym_clear_tasks(np, DID_ABORT,
                            cp->target,cp->lun, -1);
            }
#endif
        } else {
            /*
             * Error return from our internal request sense.  This
             * is bad: we must clear the contingent allegiance
             * condition otherwise the device will always return
             * BUSY.  Use a big stick.
             */
            sym_reset_scsi_target(np, cmd->device->id);
            cam_status = DID_ERROR;
        }
    } else if (cp->host_status == HS_COMPLETE)  /* Bad SCSI status */
        cam_status = DID_OK;
    else if (cp->host_status == HS_SEL_TIMEOUT) /* Selection timeout */
        cam_status = DID_NO_CONNECT;
    else if (cp->host_status == HS_UNEXPECTED)  /* Unexpected BUS FREE*/
        cam_status = DID_ERROR;
    else {                      /* Extended error */
        if (sym_verbose) {
            sym_print_addr(cmd, "COMMAND FAILED (%x %x %x).\n",
                cp->host_status, cp->ssss_status,
                cp->xerr_status);
        }
        /*
         *  Set the most appropriate value for CAM status.
         */
        cam_status = sym_xerr_cam_status(DID_ERROR, cp->xerr_status);
    }
    scsi_set_resid(cmd, resid);
    cmd->result = (drv_status << 24) + (cam_status << 16) + scsi_status;
}

static int sym_scatter(struct sym_hcb *np, struct sym_ccb *cp, struct scsi_cmnd *cmd)
{
    int segment;
    int use_sg;

    cp->data_len = 0;

    use_sg = scsi_dma_map(cmd);
    if (use_sg > 0) {
        struct scatterlist *sg;
        struct sym_tcb *tp = &np->target[cp->target];
        struct sym_tblmove *data;

        if (use_sg > SYM_CONF_MAX_SG) {
            scsi_dma_unmap(cmd);
            return -1;
        }

        data = &cp->phys.data[SYM_CONF_MAX_SG - use_sg];

        scsi_for_each_sg(cmd, sg, use_sg, segment) {
            dma_addr_t baddr = sg_dma_address(sg);
            unsigned int len = sg_dma_len(sg);

            if ((len & 1) && (tp->head.wval & EWS)) {
                len++;
                cp->odd_byte_adjustment++;
            }

            sym_build_sge(np, &data[segment], baddr, len);
            cp->data_len += len;
        }
    } else {
        segment = -2;
    }

    return segment;
}

/*
 *  Queue a SCSI command.
 */
static int sym_queue_command(struct sym_hcb *np, struct scsi_cmnd *cmd)
{
    struct scsi_device *sdev = cmd->device;
    struct sym_tcb *tp;
    struct sym_lcb *lp;
    struct sym_ccb *cp;
    int order;

    /*
     *  Retrieve the target descriptor.
     */
    tp = &np->target[sdev->id];

    /*
     *  Select tagged/untagged.
     */
    lp = sym_lp(tp, sdev->lun);
    order = (lp && lp->s.reqtags) ? M_SIMPLE_TAG : 0;

    /*
     *  Queue the SCSI IO.
     */
    cp = sym_get_ccb(np, cmd, order);
    if (!cp)
        return 1;   /* Means resource shortage */
    sym_queue_scsiio(np, cmd, cp);
    return 0;
}

/*
 *  Setup buffers and pointers that address the CDB.
 */
static inline int sym_setup_cdb(struct sym_hcb *np, struct scsi_cmnd *cmd, struct sym_ccb *cp)
{
    memcpy(cp->cdb_buf, cmd->cmnd, cmd->cmd_len);

    cp->phys.cmd.addr = CCB_BA(cp, cdb_buf[0]);
    cp->phys.cmd.size = cpu_to_scr(cmd->cmd_len);

    return 0;
}

/*
 *  Setup pointers that address the data and start the I/O.
 */
int sym_setup_data_and_start(struct sym_hcb *np, struct scsi_cmnd *cmd, struct sym_ccb *cp)
{
    u32 lastp, goalp;
    int dir;

    /*
     *  Build the CDB.
     */
    if (sym_setup_cdb(np, cmd, cp))
        goto out_abort;

    /*
     *  No direction means no data.
     */
    dir = cmd->sc_data_direction;
    if (dir != DMA_NONE) {
        cp->segments = sym_scatter(np, cp, cmd);
        if (cp->segments < 0) {
            sym_set_cam_status(cmd, DID_ERROR);
            goto out_abort;
        }

        /*
         *  No segments means no data.
         */
        if (!cp->segments)
            dir = DMA_NONE;
    } else {
        cp->data_len = 0;
        cp->segments = 0;
    }

    /*
     *  Set the data pointer.
     */
    switch (dir) {
    case DMA_BIDIRECTIONAL:
        scmd_printk(KERN_INFO, cmd, "got DMA_BIDIRECTIONAL command");
        sym_set_cam_status(cmd, DID_ERROR);
        goto out_abort;
    case DMA_TO_DEVICE:
        goalp = SCRIPTA_BA(np, data_out2) + 8;
        lastp = goalp - 8 - (cp->segments * (2*4));
        break;
    case DMA_FROM_DEVICE:
        cp->host_flags |= HF_DATA_IN;
        goalp = SCRIPTA_BA(np, data_in2) + 8;
        lastp = goalp - 8 - (cp->segments * (2*4));
        break;
    case DMA_NONE:
    default:
        lastp = goalp = SCRIPTB_BA(np, no_data);
        break;
    }

    /*
     *  Set all pointers values needed by SCRIPTS.
     */
    cp->phys.head.lastp = cpu_to_scr(lastp);
    cp->phys.head.savep = cpu_to_scr(lastp);
    cp->startp      = cp->phys.head.savep;
    cp->goalp       = cpu_to_scr(goalp);

    /*
     *  When `#ifed 1', the code below makes the driver 
     *  panic on the first attempt to write to a SCSI device.
     *  It is the first test we want to do after a driver 
     *  change that does not seem obviously safe. :)
     */
#if 0
    switch (cp->cdb_buf[0]) {
    case 0x0A: case 0x2A: case 0xAA:
        panic("XXXXXXXXXXXXX WRITE NOT YET ALLOWED XXXXXXXXXXXXXX\n");
        break;
    default:
        break;
    }
#endif

    /*
     *  activate this job.
     */
    sym_put_start_queue(np, cp);
    return 0;

out_abort:
    sym_free_ccb(np, cp);
    sym_xpt_done(np, cmd);
    return 0;
}


/*
 *  timer daemon.
 *
 *  Misused to keep the driver running when
 *  interrupts are not configured correctly.
 */
static void sym_timer(struct sym_hcb *np)
{
    unsigned long thistime = jiffies;

    /*
     *  Restart the timer.
     */
    np->s.timer.expires = thistime + SYM_CONF_TIMER_INTERVAL;
    add_timer(&np->s.timer);

    /*
     *  If we are resetting the ncr, wait for settle_time before 
     *  clearing it. Then command processing will be resumed.
     */
    if (np->s.settle_time_valid) {
        if (time_before_eq(np->s.settle_time, thistime)) {
            if (sym_verbose >= 2 )
                printk("%s: command processing resumed\n",
                       sym_name(np));
            np->s.settle_time_valid = 0;
        }
        return;
    }

    /*
     *  Nothing to do for now, but that may come.
     */
    if (np->s.lasttime + 4*HZ < thistime) {
        np->s.lasttime = thistime;
    }

#ifdef SYM_CONF_PCIQ_MAY_MISS_COMPLETIONS
    /*
     *  Some way-broken PCI bridges may lead to 
     *  completions being lost when the clearing 
     *  of the INTFLY flag by the CPU occurs 
     *  concurrently with the chip raising this flag.
     *  If this ever happen, lost completions will 
     * be reaped here.
     */
    sym_wakeup_done(np);
#endif
}


/*
 *  PCI BUS error handler.
 */
void sym_log_bus_error(struct Scsi_Host *shost)
{
    struct sym_data *sym_data = shost_priv(shost);
    struct pci_dev *pdev = sym_data->pdev;
    unsigned short pci_sts;
    pci_read_config_word(pdev, PCI_STATUS, &pci_sts);
    if (pci_sts & 0xf900) {
        pci_write_config_word(pdev, PCI_STATUS, pci_sts);
        shost_printk(KERN_WARNING, shost,
            "PCI bus error: status = 0x%04x\n", pci_sts & 0xf900);
    }
}

/*
 * queuecommand method.  Entered with the host adapter lock held and
 * interrupts disabled.
 */
static int sym53c8xx_queue_command_lck(struct scsi_cmnd *cmd,
                    void (*done)(struct scsi_cmnd *))
{
    struct sym_hcb *np = SYM_SOFTC_PTR(cmd);
    struct sym_ucmd *ucp = SYM_UCMD_PTR(cmd);
    int sts = 0;

    cmd->scsi_done = done;
    memset(ucp, 0, sizeof(*ucp));

    /*
     *  Shorten our settle_time if needed for 
     *  this command not to time out.
     */
    if (np->s.settle_time_valid && cmd->request->timeout) {
        unsigned long tlimit = jiffies + cmd->request->timeout;
        tlimit -= SYM_CONF_TIMER_INTERVAL*2;
        if (time_after(np->s.settle_time, tlimit)) {
            np->s.settle_time = tlimit;
        }
    }

    if (np->s.settle_time_valid)
        return SCSI_MLQUEUE_HOST_BUSY;

    sts = sym_queue_command(np, cmd);
    if (sts)
        return SCSI_MLQUEUE_HOST_BUSY;
    return 0;
}

static DEF_SCSI_QCMD(sym53c8xx_queue_command)

/*
 *  Linux entry point of the interrupt handler.
 */
static irqreturn_t sym53c8xx_intr(int irq, void *dev_id)
{
    struct Scsi_Host *shost = dev_id;
    struct sym_data *sym_data = shost_priv(shost);
    irqreturn_t result;

    /* Avoid spinloop trying to handle interrupts on frozen device */
    if (pci_channel_offline(sym_data->pdev))
        return IRQ_NONE;

    if (DEBUG_FLAGS & DEBUG_TINY) printf_debug ("[");

    spin_lock(shost->host_lock);
    result = sym_interrupt(shost);
    spin_unlock(shost->host_lock);

    if (DEBUG_FLAGS & DEBUG_TINY) printf_debug ("]\n");

    return result;
}

/*
 *  Linux entry point of the timer handler
 */
static void sym53c8xx_timer(unsigned long npref)
{
    struct sym_hcb *np = (struct sym_hcb *)npref;
    unsigned long flags;

    spin_lock_irqsave(np->s.host->host_lock, flags);
    sym_timer(np);
    spin_unlock_irqrestore(np->s.host->host_lock, flags);
}


/*
 *  What the eh thread wants us to perform.
 */
#define SYM_EH_ABORT        0
#define SYM_EH_DEVICE_RESET 1
#define SYM_EH_BUS_RESET    2
#define SYM_EH_HOST_RESET   3

/*
 *  Generic method for our eh processing.
 *  The 'op' argument tells what we have to do.
 */
static int sym_eh_handler(int op, char *opname, struct scsi_cmnd *cmd)
{
    struct sym_ucmd *ucmd = SYM_UCMD_PTR(cmd);
    struct Scsi_Host *shost = cmd->device->host;
    struct sym_data *sym_data = shost_priv(shost);
    struct pci_dev *pdev = sym_data->pdev;
    struct sym_hcb *np = sym_data->ncb;
    SYM_QUEHEAD *qp;
    int cmd_queued = 0;
    int sts = -1;
    struct completion eh_done;

    scmd_printk(KERN_WARNING, cmd, "%s operation started\n", opname);

    /* We may be in an error condition because the PCI bus
     * went down. In this case, we need to wait until the
     * PCI bus is reset, the card is reset, and only then
     * proceed with the scsi error recovery.  There's no
     * point in hurrying; take a leisurely wait.
     */
#define WAIT_FOR_PCI_RECOVERY   35
    if (pci_channel_offline(pdev)) {
        int finished_reset = 0;
        init_completion(&eh_done);
        spin_lock_irq(shost->host_lock);
        /* Make sure we didn't race */
        if (pci_channel_offline(pdev)) {
            BUG_ON(sym_data->io_reset);
            sym_data->io_reset = &eh_done;
        } else {
            finished_reset = 1;
        }
        spin_unlock_irq(shost->host_lock);
        if (!finished_reset)
            finished_reset = wait_for_completion_timeout
                        (sym_data->io_reset,
                        WAIT_FOR_PCI_RECOVERY*HZ);
        spin_lock_irq(shost->host_lock);
        sym_data->io_reset = NULL;
        spin_unlock_irq(shost->host_lock);
        if (!finished_reset)
            return SCSI_FAILED;
    }

    spin_lock_irq(shost->host_lock);
    /* This one is queued in some place -> to wait for completion */
    FOR_EACH_QUEUED_ELEMENT(&np->busy_ccbq, qp) {
        struct sym_ccb *cp = sym_que_entry(qp, struct sym_ccb, link_ccbq);
        if (cp->cmd == cmd) {
            cmd_queued = 1;
            break;
        }
    }

    /* Try to proceed the operation we have been asked for */
    sts = -1;
    switch(op) {
    case SYM_EH_ABORT:
        sts = sym_abort_scsiio(np, cmd, 1);
        break;
    case SYM_EH_DEVICE_RESET:
        sts = sym_reset_scsi_target(np, cmd->device->id);
        break;
    case SYM_EH_BUS_RESET:
        sym_reset_scsi_bus(np, 1);
        sts = 0;
        break;
    case SYM_EH_HOST_RESET:
        sym_reset_scsi_bus(np, 0);
        sym_start_up(shost, 1);
        sts = 0;
        break;
    default:
        break;
    }

    /* On error, restore everything and cross fingers :) */
    if (sts)
        cmd_queued = 0;

    if (cmd_queued) {
        init_completion(&eh_done);
        ucmd->eh_done = &eh_done;
        spin_unlock_irq(shost->host_lock);
        if (!wait_for_completion_timeout(&eh_done, 5*HZ)) {
            ucmd->eh_done = NULL;
            sts = -2;
        }
    } else {
        spin_unlock_irq(shost->host_lock);
    }

    dev_warn(&cmd->device->sdev_gendev, "%s operation %s.\n", opname,
            sts==0 ? "complete" :sts==-2 ? "timed-out" : "failed");
    return sts ? SCSI_FAILED : SCSI_SUCCESS;
}


/*
 * Error handlers called from the eh thread (one thread per HBA).
 */
static int sym53c8xx_eh_abort_handler(struct scsi_cmnd *cmd)
{
    return sym_eh_handler(SYM_EH_ABORT, "ABORT", cmd);
}

static int sym53c8xx_eh_device_reset_handler(struct scsi_cmnd *cmd)
{
    return sym_eh_handler(SYM_EH_DEVICE_RESET, "DEVICE RESET", cmd);
}

static int sym53c8xx_eh_bus_reset_handler(struct scsi_cmnd *cmd)
{
    return sym_eh_handler(SYM_EH_BUS_RESET, "BUS RESET", cmd);
}

static int sym53c8xx_eh_host_reset_handler(struct scsi_cmnd *cmd)
{
    return sym_eh_handler(SYM_EH_HOST_RESET, "HOST RESET", cmd);
}

/*
 *  Tune device queuing depth, according to various limits.
 */
static void sym_tune_dev_queuing(struct sym_tcb *tp, int lun, u_short reqtags)
{
    struct sym_lcb *lp = sym_lp(tp, lun);
    u_short oldtags;

    if (!lp)
        return;

    oldtags = lp->s.reqtags;

    if (reqtags > lp->s.scdev_depth)
        reqtags = lp->s.scdev_depth;

    lp->s.reqtags     = reqtags;

    if (reqtags != oldtags) {
        dev_info(&tp->starget->dev,
                 "tagged command queuing %s, command queue depth %d.\n",
                  lp->s.reqtags ? "enabled" : "disabled", reqtags);
    }
}

static int sym53c8xx_slave_alloc(struct scsi_device *sdev)
{
    struct sym_hcb *np = sym_get_hcb(sdev->host);
    struct sym_tcb *tp = &np->target[sdev->id];
    struct sym_lcb *lp;
    unsigned long flags;
    int error;

    if (sdev->id >= SYM_CONF_MAX_TARGET || sdev->lun >= SYM_CONF_MAX_LUN)
        return -ENXIO;

    spin_lock_irqsave(np->s.host->host_lock, flags);

    /*
     * Fail the device init if the device is flagged NOSCAN at BOOT in
     * the NVRAM.  This may speed up boot and maintain coherency with
     * BIOS device numbering.  Clearing the flag allows the user to
     * rescan skipped devices later.  We also return an error for
     * devices not flagged for SCAN LUNS in the NVRAM since some single
     * lun devices behave badly when asked for a non zero LUN.
     */

    if (tp->usrflags & SYM_SCAN_BOOT_DISABLED) {
        tp->usrflags &= ~SYM_SCAN_BOOT_DISABLED;
        starget_printk(KERN_INFO, sdev->sdev_target,
                "Scan at boot disabled in NVRAM\n");
        error = -ENXIO;
        goto out;
    }

    if (tp->usrflags & SYM_SCAN_LUNS_DISABLED) {
        if (sdev->lun != 0) {
            error = -ENXIO;
            goto out;
        }
        starget_printk(KERN_INFO, sdev->sdev_target,
                "Multiple LUNs disabled in NVRAM\n");
    }

    lp = sym_alloc_lcb(np, sdev->id, sdev->lun);
    if (!lp) {
        error = -ENOMEM;
        goto out;
    }
    if (tp->nlcb == 1)
        tp->starget = sdev->sdev_target;

    spi_min_period(tp->starget) = tp->usr_period;
    spi_max_width(tp->starget) = tp->usr_width;

    error = 0;
out:
    spin_unlock_irqrestore(np->s.host->host_lock, flags);

    return error;
}

/*
 * Linux entry point for device queue sizing.
 */
static int sym53c8xx_slave_configure(struct scsi_device *sdev)
{
    struct sym_hcb *np = sym_get_hcb(sdev->host);
    struct sym_tcb *tp = &np->target[sdev->id];
    struct sym_lcb *lp = sym_lp(tp, sdev->lun);
    int reqtags, depth_to_use;

    /*
     *  Get user flags.
     */
    lp->curr_flags = lp->user_flags;

    /*
     *  Select queue depth from driver setup.
     *  Do not use more than configured by user.
     *  Use at least 1.
     *  Do not use more than our maximum.
     */
    reqtags = sym_driver_setup.max_tag;
    if (reqtags > tp->usrtags)
        reqtags = tp->usrtags;
    if (!sdev->tagged_supported)
        reqtags = 0;
    if (reqtags > SYM_CONF_MAX_TAG)
        reqtags = SYM_CONF_MAX_TAG;
    depth_to_use = reqtags ? reqtags : 1;
    scsi_adjust_queue_depth(sdev,
                sdev->tagged_supported ? MSG_SIMPLE_TAG : 0,
                depth_to_use);
    lp->s.scdev_depth = depth_to_use;
    sym_tune_dev_queuing(tp, sdev->lun, reqtags);

    if (!spi_initial_dv(sdev->sdev_target))
        spi_dv_device(sdev);

    return 0;
}

static void sym53c8xx_slave_destroy(struct scsi_device *sdev)
{
    struct sym_hcb *np = sym_get_hcb(sdev->host);
    struct sym_tcb *tp = &np->target[sdev->id];
    struct sym_lcb *lp = sym_lp(tp, sdev->lun);
    unsigned long flags;

    /* if slave_alloc returned before allocating a sym_lcb, return */
    if (!lp)
        return;

    spin_lock_irqsave(np->s.host->host_lock, flags);

    if (lp->busy_itlq || lp->busy_itl) {
        /*
         * This really shouldn't happen, but we can't return an error
         * so let's try to stop all on-going I/O.
         */
        starget_printk(KERN_WARNING, tp->starget,
                   "Removing busy LCB (%d)\n", sdev->lun);
        sym_reset_scsi_bus(np, 1);
    }

    if (sym_free_lcb(np, sdev->id, sdev->lun) == 0) {
        /*
         * It was the last unit for this target.
         */
        tp->head.sval        = 0;
        tp->head.wval        = np->rv_scntl3;
        tp->head.uval        = 0;
        tp->tgoal.check_nego = 1;
        tp->starget      = NULL;
    }

    spin_unlock_irqrestore(np->s.host->host_lock, flags);
}

/*
 *  Linux entry point for info() function
 */
static const char *sym53c8xx_info (struct Scsi_Host *host)
{
    return SYM_DRIVER_NAME;
}


#ifdef SYM_LINUX_PROC_INFO_SUPPORT
/*
 *  Proc file system stuff
 *
 *  A read operation returns adapter information.
 *  A write operation is a control command.
 *  The string is parsed in the driver code and the command is passed 
 *  to the sym_usercmd() function.
 */

#ifdef SYM_LINUX_USER_COMMAND_SUPPORT

struct  sym_usrcmd {
    u_long  target;
    u_long  lun;
    u_long  data;
    u_long  cmd;
};

#define UC_SETSYNC      10
#define UC_SETTAGS  11
#define UC_SETDEBUG 12
#define UC_SETWIDE  14
#define UC_SETFLAG  15
#define UC_SETVERBOSE   17
#define UC_RESETDEV 18
#define UC_CLEARDEV 19

static void sym_exec_user_command (struct sym_hcb *np, struct sym_usrcmd *uc)
{
    struct sym_tcb *tp;
    int t, l;

    switch (uc->cmd) {
    case 0: return;

#ifdef SYM_LINUX_DEBUG_CONTROL_SUPPORT
    case UC_SETDEBUG:
        sym_debug_flags = uc->data;
        break;
#endif
    case UC_SETVERBOSE:
        np->verbose = uc->data;
        break;
    default:
        /*
         * We assume that other commands apply to targets.
         * This should always be the case and avoid the below 
         * 4 lines to be repeated 6 times.
         */
        for (t = 0; t < SYM_CONF_MAX_TARGET; t++) {
            if (!((uc->target >> t) & 1))
                continue;
            tp = &np->target[t];
            if (!tp->nlcb)
                continue;

            switch (uc->cmd) {

            case UC_SETSYNC:
                if (!uc->data || uc->data >= 255) {
                    tp->tgoal.iu = tp->tgoal.dt =
                        tp->tgoal.qas = 0;
                    tp->tgoal.offset = 0;
                } else if (uc->data <= 9 && np->minsync_dt) {
                    if (uc->data < np->minsync_dt)
                        uc->data = np->minsync_dt;
                    tp->tgoal.iu = tp->tgoal.dt =
                        tp->tgoal.qas = 1;
                    tp->tgoal.width = 1;
                    tp->tgoal.period = uc->data;
                    tp->tgoal.offset = np->maxoffs_dt;
                } else {
                    if (uc->data < np->minsync)
                        uc->data = np->minsync;
                    tp->tgoal.iu = tp->tgoal.dt =
                        tp->tgoal.qas = 0;
                    tp->tgoal.period = uc->data;
                    tp->tgoal.offset = np->maxoffs;
                }
                tp->tgoal.check_nego = 1;
                break;
            case UC_SETWIDE:
                tp->tgoal.width = uc->data ? 1 : 0;
                tp->tgoal.check_nego = 1;
                break;
            case UC_SETTAGS:
                for (l = 0; l < SYM_CONF_MAX_LUN; l++)
                    sym_tune_dev_queuing(tp, l, uc->data);
                break;
            case UC_RESETDEV:
                tp->to_reset = 1;
                np->istat_sem = SEM;
                OUTB(np, nc_istat, SIGP|SEM);
                break;
            case UC_CLEARDEV:
                for (l = 0; l < SYM_CONF_MAX_LUN; l++) {
                    struct sym_lcb *lp = sym_lp(tp, l);
                    if (lp) lp->to_clear = 1;
                }
                np->istat_sem = SEM;
                OUTB(np, nc_istat, SIGP|SEM);
                break;
            case UC_SETFLAG:
                tp->usrflags = uc->data;
                break;
            }
        }
        break;
    }
}

static int sym_skip_spaces(char *ptr, int len)
{
    int cnt, c;

    for (cnt = len; cnt > 0 && (c = *ptr++) && isspace(c); cnt--);

    return (len - cnt);
}

static int get_int_arg(char *ptr, int len, u_long *pv)
{
    char *end;

    *pv = simple_strtoul(ptr, &end, 10);
    return (end - ptr);
}

static int is_keyword(char *ptr, int len, char *verb)
{
    int verb_len = strlen(verb);

    if (len >= verb_len && !memcmp(verb, ptr, verb_len))
        return verb_len;
    else
        return 0;
}

#define SKIP_SPACES(ptr, len)                       \
    if ((arg_len = sym_skip_spaces(ptr, len)) < 1)          \
        return -EINVAL;                     \
    ptr += arg_len; len -= arg_len;

#define GET_INT_ARG(ptr, len, v)                    \
    if (!(arg_len = get_int_arg(ptr, len, &(v))))           \
        return -EINVAL;                     \
    ptr += arg_len; len -= arg_len;


/*
 * Parse a control command
 */

static int sym_user_command(struct Scsi_Host *shost, char *buffer, int length)
{
    struct sym_hcb *np = sym_get_hcb(shost);
    char *ptr   = buffer;
    int len     = length;
    struct sym_usrcmd cmd, *uc = &cmd;
    int     arg_len;
    u_long      target;

    memset(uc, 0, sizeof(*uc));

    if (len > 0 && ptr[len-1] == '\n')
        --len;

    if  ((arg_len = is_keyword(ptr, len, "setsync")) != 0)
        uc->cmd = UC_SETSYNC;
    else if ((arg_len = is_keyword(ptr, len, "settags")) != 0)
        uc->cmd = UC_SETTAGS;
    else if ((arg_len = is_keyword(ptr, len, "setverbose")) != 0)
        uc->cmd = UC_SETVERBOSE;
    else if ((arg_len = is_keyword(ptr, len, "setwide")) != 0)
        uc->cmd = UC_SETWIDE;
#ifdef SYM_LINUX_DEBUG_CONTROL_SUPPORT
    else if ((arg_len = is_keyword(ptr, len, "setdebug")) != 0)
        uc->cmd = UC_SETDEBUG;
#endif
    else if ((arg_len = is_keyword(ptr, len, "setflag")) != 0)
        uc->cmd = UC_SETFLAG;
    else if ((arg_len = is_keyword(ptr, len, "resetdev")) != 0)
        uc->cmd = UC_RESETDEV;
    else if ((arg_len = is_keyword(ptr, len, "cleardev")) != 0)
        uc->cmd = UC_CLEARDEV;
    else
        arg_len = 0;

#ifdef DEBUG_PROC_INFO
printk("sym_user_command: arg_len=%d, cmd=%ld\n", arg_len, uc->cmd);
#endif

    if (!arg_len)
        return -EINVAL;
    ptr += arg_len; len -= arg_len;

    switch(uc->cmd) {
    case UC_SETSYNC:
    case UC_SETTAGS:
    case UC_SETWIDE:
    case UC_SETFLAG:
    case UC_RESETDEV:
    case UC_CLEARDEV:
        SKIP_SPACES(ptr, len);
        if ((arg_len = is_keyword(ptr, len, "all")) != 0) {
            ptr += arg_len; len -= arg_len;
            uc->target = ~0;
        } else {
            GET_INT_ARG(ptr, len, target);
            uc->target = (1<<target);
#ifdef DEBUG_PROC_INFO
printk("sym_user_command: target=%ld\n", target);
#endif
        }
        break;
    }

    switch(uc->cmd) {
    case UC_SETVERBOSE:
    case UC_SETSYNC:
    case UC_SETTAGS:
    case UC_SETWIDE:
        SKIP_SPACES(ptr, len);
        GET_INT_ARG(ptr, len, uc->data);
#ifdef DEBUG_PROC_INFO
printk("sym_user_command: data=%ld\n", uc->data);
#endif
        break;
#ifdef SYM_LINUX_DEBUG_CONTROL_SUPPORT
    case UC_SETDEBUG:
        while (len > 0) {
            SKIP_SPACES(ptr, len);
            if  ((arg_len = is_keyword(ptr, len, "alloc")))
                uc->data |= DEBUG_ALLOC;
            else if ((arg_len = is_keyword(ptr, len, "phase")))
                uc->data |= DEBUG_PHASE;
            else if ((arg_len = is_keyword(ptr, len, "queue")))
                uc->data |= DEBUG_QUEUE;
            else if ((arg_len = is_keyword(ptr, len, "result")))
                uc->data |= DEBUG_RESULT;
            else if ((arg_len = is_keyword(ptr, len, "scatter")))
                uc->data |= DEBUG_SCATTER;
            else if ((arg_len = is_keyword(ptr, len, "script")))
                uc->data |= DEBUG_SCRIPT;
            else if ((arg_len = is_keyword(ptr, len, "tiny")))
                uc->data |= DEBUG_TINY;
            else if ((arg_len = is_keyword(ptr, len, "timing")))
                uc->data |= DEBUG_TIMING;
            else if ((arg_len = is_keyword(ptr, len, "nego")))
                uc->data |= DEBUG_NEGO;
            else if ((arg_len = is_keyword(ptr, len, "tags")))
                uc->data |= DEBUG_TAGS;
            else if ((arg_len = is_keyword(ptr, len, "pointer")))
                uc->data |= DEBUG_POINTER;
            else
                return -EINVAL;
            ptr += arg_len; len -= arg_len;
        }
#ifdef DEBUG_PROC_INFO
printk("sym_user_command: data=%ld\n", uc->data);
#endif
        break;
#endif /* SYM_LINUX_DEBUG_CONTROL_SUPPORT */
    case UC_SETFLAG:
        while (len > 0) {
            SKIP_SPACES(ptr, len);
            if  ((arg_len = is_keyword(ptr, len, "no_disc")))
                uc->data &= ~SYM_DISC_ENABLED;
            else
                return -EINVAL;
            ptr += arg_len; len -= arg_len;
        }
        break;
    default:
        break;
    }

    if (len)
        return -EINVAL;
    else {
        unsigned long flags;

        spin_lock_irqsave(shost->host_lock, flags);
        sym_exec_user_command(np, uc);
        spin_unlock_irqrestore(shost->host_lock, flags);
    }
    return length;
}

#endif  /* SYM_LINUX_USER_COMMAND_SUPPORT */


#ifdef SYM_LINUX_USER_INFO_SUPPORT
/*
 *  Informations through the proc file system.
 */
struct info_str {
    char *buffer;
    int length;
    int offset;
    int pos;
};

static void copy_mem_info(struct info_str *info, char *data, int len)
{
    if (info->pos + len > info->length)
        len = info->length - info->pos;

    if (info->pos + len < info->offset) {
        info->pos += len;
        return;
    }
    if (info->pos < info->offset) {
        data += (info->offset - info->pos);
        len  -= (info->offset - info->pos);
    }

    if (len > 0) {
        memcpy(info->buffer + info->pos, data, len);
        info->pos += len;
    }
}

static int copy_info(struct info_str *info, char *fmt, ...)
{
    va_list args;
    char buf[81];
    int len;

    va_start(args, fmt);
    len = vsprintf(buf, fmt, args);
    va_end(args);

    copy_mem_info(info, buf, len);
    return len;
}

/*
 *  Copy formatted information into the input buffer.
 */
static int sym_host_info(struct Scsi_Host *shost, char *ptr, off_t offset, int len)
{
    struct sym_data *sym_data = shost_priv(shost);
    struct pci_dev *pdev = sym_data->pdev;
    struct sym_hcb *np = sym_data->ncb;
    struct info_str info;

    info.buffer = ptr;
    info.length = len;
    info.offset = offset;
    info.pos    = 0;

    copy_info(&info, "Chip " NAME53C "%s, device id 0x%x, "
             "revision id 0x%x\n", np->s.chip_name,
             pdev->device, pdev->revision);
    copy_info(&info, "At PCI address %s, IRQ %u\n",
             pci_name(pdev), pdev->irq);
    copy_info(&info, "Min. period factor %d, %s SCSI BUS%s\n",
             (int) (np->minsync_dt ? np->minsync_dt : np->minsync),
             np->maxwide ? "Wide" : "Narrow",
             np->minsync_dt ? ", DT capable" : "");

    copy_info(&info, "Max. started commands %d, "
             "max. commands per LUN %d\n",
             SYM_CONF_MAX_START, SYM_CONF_MAX_TAG);

    return info.pos > info.offset? info.pos - info.offset : 0;
}
#endif /* SYM_LINUX_USER_INFO_SUPPORT */

/*
 *  Entry point of the scsi proc fs of the driver.
 *  - func = 0 means read  (returns adapter infos)
 *  - func = 1 means write (not yet merget from sym53c8xx)
 */
static int sym53c8xx_proc_info(struct Scsi_Host *shost, char *buffer,
            char **start, off_t offset, int length, int func)
{
    int retv;

    if (func) {
#ifdef  SYM_LINUX_USER_COMMAND_SUPPORT
        retv = sym_user_command(shost, buffer, length);
#else
        retv = -EINVAL;
#endif
    } else {
        if (start)
            *start = buffer;
#ifdef SYM_LINUX_USER_INFO_SUPPORT
        retv = sym_host_info(shost, buffer, offset, length);
#else
        retv = -EINVAL;
#endif
    }

    return retv;
}
#endif /* SYM_LINUX_PROC_INFO_SUPPORT */

/*
 * Free resources claimed by sym_iomap_device().  Note that
 * sym_free_resources() should be used instead of this function after calling
 * sym_attach().
 */
static void __devinit
sym_iounmap_device(struct sym_device *device)
{
    if (device->s.ioaddr)
        pci_iounmap(device->pdev, device->s.ioaddr);
    if (device->s.ramaddr)
        pci_iounmap(device->pdev, device->s.ramaddr);
}

/*
 *  Free controller resources.
 */
static void sym_free_resources(struct sym_hcb *np, struct pci_dev *pdev,
        int do_free_irq)
{
    /*
     *  Free O/S specific resources.
     */
    if (do_free_irq)
        free_irq(pdev->irq, np->s.host);
    if (np->s.ioaddr)
        pci_iounmap(pdev, np->s.ioaddr);
    if (np->s.ramaddr)
        pci_iounmap(pdev, np->s.ramaddr);
    /*
     *  Free O/S independent resources.
     */
    sym_hcb_free(np);

    sym_mfree_dma(np, sizeof(*np), "HCB");
}

/*
 *  Host attach and initialisations.
 *
 *  Allocate host data and ncb structure.
 *  Remap MMIO region.
 *  Do chip initialization.
 *  If all is OK, install interrupt handling and
 *  start the timer daemon.
 */
static struct Scsi_Host * __devinit sym_attach(struct scsi_host_template *tpnt,
        int unit, struct sym_device *dev)
{
    struct sym_data *sym_data;
    struct sym_hcb *np = NULL;
    struct Scsi_Host *shost = NULL;
    struct pci_dev *pdev = dev->pdev;
    unsigned long flags;
    struct sym_fw *fw;
    int do_free_irq = 0;

    printk(KERN_INFO "sym%d: <%s> rev 0x%x at pci %s irq %u\n",
        unit, dev->chip.name, pdev->revision, pci_name(pdev),
        pdev->irq);

    /*
     *  Get the firmware for this chip.
     */
    fw = sym_find_firmware(&dev->chip);
    if (!fw)
        goto attach_failed;

    shost = scsi_host_alloc(tpnt, sizeof(*sym_data));
    if (!shost)
        goto attach_failed;
    sym_data = shost_priv(shost);

    /*
     *  Allocate immediately the host control block, 
     *  since we are only expecting to succeed. :)
     *  We keep track in the HCB of all the resources that 
     *  are to be released on error.
     */
    np = __sym_calloc_dma(&pdev->dev, sizeof(*np), "HCB");
    if (!np)
        goto attach_failed;
    np->bus_dmat = &pdev->dev; /* Result in 1 DMA pool per HBA */
    sym_data->ncb = np;
    sym_data->pdev = pdev;
    np->s.host = shost;

    pci_set_drvdata(pdev, shost);

    /*
     *  Copy some useful infos to the HCB.
     */
    np->hcb_ba  = vtobus(np);
    np->verbose = sym_driver_setup.verbose;
    np->s.unit  = unit;
    np->features    = dev->chip.features;
    np->clock_divn  = dev->chip.nr_divisor;
    np->maxoffs = dev->chip.offset_max;
    np->maxburst    = dev->chip.burst_max;
    np->myaddr  = dev->host_id;
    np->mmio_ba = (u32)dev->mmio_base;
    np->ram_ba  = (u32)dev->ram_base;
    np->s.ioaddr    = dev->s.ioaddr;
    np->s.ramaddr   = dev->s.ramaddr;

    /*
     *  Edit its name.
     */
    strlcpy(np->s.chip_name, dev->chip.name, sizeof(np->s.chip_name));
    sprintf(np->s.inst_name, "sym%d", np->s.unit);

    if ((SYM_CONF_DMA_ADDRESSING_MODE > 0) && (np->features & FE_DAC) &&
            !pci_set_dma_mask(pdev, DMA_DAC_MASK)) {
        set_dac(np);
    } else if (pci_set_dma_mask(pdev, DMA_BIT_MASK(32))) {
        printf_warning("%s: No suitable DMA available\n", sym_name(np));
        goto attach_failed;
    }

    if (sym_hcb_attach(shost, fw, dev->nvram))
        goto attach_failed;

    /*
     *  Install the interrupt handler.
     *  If we synchonize the C code with SCRIPTS on interrupt, 
     *  we do not want to share the INTR line at all.
     */
    if (request_irq(pdev->irq, sym53c8xx_intr, IRQF_SHARED, NAME53C8XX,
            shost)) {
        printf_err("%s: request irq %u failure\n",
            sym_name(np), pdev->irq);
        goto attach_failed;
    }
    do_free_irq = 1;

    /*
     *  After SCSI devices have been opened, we cannot
     *  reset the bus safely, so we do it here.
     */
    spin_lock_irqsave(shost->host_lock, flags);
    if (sym_reset_scsi_bus(np, 0))
        goto reset_failed;

    /*
     *  Start the SCRIPTS.
     */
    sym_start_up(shost, 1);

    /*
     *  Start the timer daemon
     */
    init_timer(&np->s.timer);
    np->s.timer.data     = (unsigned long) np;
    np->s.timer.function = sym53c8xx_timer;
    np->s.lasttime=0;
    sym_timer (np);

    /*
     *  Fill Linux host instance structure
     *  and return success.
     */
    shost->max_channel  = 0;
    shost->this_id      = np->myaddr;
    shost->max_id       = np->maxwide ? 16 : 8;
    shost->max_lun      = SYM_CONF_MAX_LUN;
    shost->unique_id    = pci_resource_start(pdev, 0);
    shost->cmd_per_lun  = SYM_CONF_MAX_TAG;
    shost->can_queue    = (SYM_CONF_MAX_START-2);
    shost->sg_tablesize = SYM_CONF_MAX_SG;
    shost->max_cmd_len  = 16;
    BUG_ON(sym2_transport_template == NULL);
    shost->transportt   = sym2_transport_template;

    /* 53c896 rev 1 errata: DMA may not cross 16MB boundary */
    if (pdev->device == PCI_DEVICE_ID_NCR_53C896 && pdev->revision < 2)
        shost->dma_boundary = 0xFFFFFF;

    spin_unlock_irqrestore(shost->host_lock, flags);

    return shost;

 reset_failed:
    printf_err("%s: FATAL ERROR: CHECK SCSI BUS - CABLES, "
           "TERMINATION, DEVICE POWER etc.!\n", sym_name(np));
    spin_unlock_irqrestore(shost->host_lock, flags);
 attach_failed:
    printf_info("sym%d: giving up ...\n", unit);
    if (np)
        sym_free_resources(np, pdev, do_free_irq);
    else
        sym_iounmap_device(dev);
    if (shost)
        scsi_host_put(shost);

    return NULL;
 }


/*
 *    Detect and try to read SYMBIOS and TEKRAM NVRAM.
 */
#if SYM_CONF_NVRAM_SUPPORT
static void __devinit sym_get_nvram(struct sym_device *devp, struct sym_nvram *nvp)
{
    devp->nvram = nvp;
    nvp->type = 0;

    sym_read_nvram(devp, nvp);
}
#else
static inline void sym_get_nvram(struct sym_device *devp, struct sym_nvram *nvp)
{
}
#endif  /* SYM_CONF_NVRAM_SUPPORT */

static int __devinit sym_check_supported(struct sym_device *device)
{
    struct sym_chip *chip;
    struct pci_dev *pdev = device->pdev;
    unsigned long io_port = pci_resource_start(pdev, 0);
    int i;

    /*
     *  If user excluded this chip, do not initialize it.
     *  I hate this code so much.  Must kill it.
     */
    if (io_port) {
        for (i = 0 ; i < 8 ; i++) {
            if (sym_driver_setup.excludes[i] == io_port)
                return -ENODEV;
        }
    }

    /*
     * Check if the chip is supported.  Then copy the chip description
     * to our device structure so we can make it match the actual device
     * and options.
     */
    chip = sym_lookup_chip_table(pdev->device, pdev->revision);
    if (!chip) {
        dev_info(&pdev->dev, "device not supported\n");
        return -ENODEV;
    }
    memcpy(&device->chip, chip, sizeof(device->chip));

    return 0;
}

/*
 * Ignore Symbios chips controlled by various RAID controllers.
 * These controllers set value 0x52414944 at RAM end - 16.
 */
static int __devinit sym_check_raid(struct sym_device *device)
{
    unsigned int ram_size, ram_val;

    if (!device->s.ramaddr)
        return 0;

    if (device->chip.features & FE_RAM8K)
        ram_size = 8192;
    else
        ram_size = 4096;

    ram_val = readl(device->s.ramaddr + ram_size - 16);
    if (ram_val != 0x52414944)
        return 0;

    dev_info(&device->pdev->dev,
            "not initializing, driven by RAID controller.\n");
    return -ENODEV;
}

static int __devinit sym_set_workarounds(struct sym_device *device)
{
    struct sym_chip *chip = &device->chip;
    struct pci_dev *pdev = device->pdev;
    u_short status_reg;

    /*
     *  (ITEM 12 of a DEL about the 896 I haven't yet).
     *  We must ensure the chip will use WRITE AND INVALIDATE.
     *  The revision number limit is for now arbitrary.
     */
    if (pdev->device == PCI_DEVICE_ID_NCR_53C896 && pdev->revision < 0x4) {
        chip->features  |= (FE_WRIE | FE_CLSE);
    }

    /* If the chip can do Memory Write Invalidate, enable it */
    if (chip->features & FE_WRIE) {
        if (pci_set_mwi(pdev))
            return -ENODEV;
    }

    /*
     *  Work around for errant bit in 895A. The 66Mhz
     *  capable bit is set erroneously. Clear this bit.
     *  (Item 1 DEL 533)
     *
     *  Make sure Config space and Features agree.
     *
     *  Recall: writes are not normal to status register -
     *  write a 1 to clear and a 0 to leave unchanged.
     *  Can only reset bits.
     */
    pci_read_config_word(pdev, PCI_STATUS, &status_reg);
    if (chip->features & FE_66MHZ) {
        if (!(status_reg & PCI_STATUS_66MHZ))
            chip->features &= ~FE_66MHZ;
    } else {
        if (status_reg & PCI_STATUS_66MHZ) {
            status_reg = PCI_STATUS_66MHZ;
            pci_write_config_word(pdev, PCI_STATUS, status_reg);
            pci_read_config_word(pdev, PCI_STATUS, &status_reg);
        }
    }

    return 0;
}

/*
 * Map HBA registers and on-chip SRAM (if present).
 */
static int __devinit
sym_iomap_device(struct sym_device *device)
{
    struct pci_dev *pdev = device->pdev;
    struct pci_bus_region bus_addr;
    int i = 2;

    pcibios_resource_to_bus(pdev, &bus_addr, &pdev->resource[1]);
    device->mmio_base = bus_addr.start;

    if (device->chip.features & FE_RAM) {
        /*
         * If the BAR is 64-bit, resource 2 will be occupied by the
         * upper 32 bits
         */
        if (!pdev->resource[i].flags)
            i++;
        pcibios_resource_to_bus(pdev, &bus_addr, &pdev->resource[i]);
        device->ram_base = bus_addr.start;
    }

#ifdef CONFIG_SCSI_SYM53C8XX_MMIO
    if (device->mmio_base)
        device->s.ioaddr = pci_iomap(pdev, 1,
                        pci_resource_len(pdev, 1));
#endif
    if (!device->s.ioaddr)
        device->s.ioaddr = pci_iomap(pdev, 0,
                        pci_resource_len(pdev, 0));
    if (!device->s.ioaddr) {
        dev_err(&pdev->dev, "could not map registers; giving up.\n");
        return -EIO;
    }
    if (device->ram_base) {
        device->s.ramaddr = pci_iomap(pdev, i,
                        pci_resource_len(pdev, i));
        if (!device->s.ramaddr) {
            dev_warn(&pdev->dev,
                "could not map SRAM; continuing anyway.\n");
            device->ram_base = 0;
        }
    }

    return 0;
}

/*
 * The NCR PQS and PDS cards are constructed as a DEC bridge
 * behind which sits a proprietary NCR memory controller and
 * either four or two 53c875s as separate devices.  We can tell
 * if an 875 is part of a PQS/PDS or not since if it is, it will
 * be on the same bus as the memory controller.  In its usual
 * mode of operation, the 875s are slaved to the memory
 * controller for all transfers.  To operate with the Linux
 * driver, the memory controller is disabled and the 875s
 * freed to function independently.  The only wrinkle is that
 * the preset SCSI ID (which may be zero) must be read in from
 * a special configuration space register of the 875.
 */
static void sym_config_pqs(struct pci_dev *pdev, struct sym_device *sym_dev)
{
    int slot;
    u8 tmp;

    for (slot = 0; slot < 256; slot++) {
        struct pci_dev *memc = pci_get_slot(pdev->bus, slot);

        if (!memc || memc->vendor != 0x101a || memc->device == 0x0009) {
            pci_dev_put(memc);
            continue;
        }

        /* bit 1: allow individual 875 configuration */
        pci_read_config_byte(memc, 0x44, &tmp);
        if ((tmp & 0x2) == 0) {
            tmp |= 0x2;
            pci_write_config_byte(memc, 0x44, tmp);
        }

        /* bit 2: drive individual 875 interrupts to the bus */
        pci_read_config_byte(memc, 0x45, &tmp);
        if ((tmp & 0x4) == 0) {
            tmp |= 0x4;
            pci_write_config_byte(memc, 0x45, tmp);
        }

        pci_dev_put(memc);
        break;
    }

    pci_read_config_byte(pdev, 0x84, &tmp);
    sym_dev->host_id = tmp;
}

/*
 *  Called before unloading the module.
 *  Detach the host.
 *  We have to free resources and halt the NCR chip.
 */
static int sym_detach(struct Scsi_Host *shost, struct pci_dev *pdev)
{
    struct sym_hcb *np = sym_get_hcb(shost);
    printk("%s: detaching ...\n", sym_name(np));

    del_timer_sync(&np->s.timer);

    /*
     * Reset NCR chip.
     * We should use sym_soft_reset(), but we don't want to do 
     * so, since we may not be safe if interrupts occur.
     */
    printk("%s: resetting chip\n", sym_name(np));
    OUTB(np, nc_istat, SRST);
    INB(np, nc_mbox1);
    udelay(10);
    OUTB(np, nc_istat, 0);

    sym_free_resources(np, pdev, 1);
    scsi_host_put(shost);

    return 1;
}

/*
 * Driver host template.
 */
static struct scsi_host_template sym2_template = {
    .module         = THIS_MODULE,
    .name           = "sym53c8xx",
    .info           = sym53c8xx_info, 
    .queuecommand       = sym53c8xx_queue_command,
    .slave_alloc        = sym53c8xx_slave_alloc,
    .slave_configure    = sym53c8xx_slave_configure,
    .slave_destroy      = sym53c8xx_slave_destroy,
    .eh_abort_handler   = sym53c8xx_eh_abort_handler,
    .eh_device_reset_handler = sym53c8xx_eh_device_reset_handler,
    .eh_bus_reset_handler   = sym53c8xx_eh_bus_reset_handler,
    .eh_host_reset_handler  = sym53c8xx_eh_host_reset_handler,
    .this_id        = 7,
    .use_clustering     = ENABLE_CLUSTERING,
    .max_sectors        = 0xFFFF,
#ifdef SYM_LINUX_PROC_INFO_SUPPORT
    .proc_info      = sym53c8xx_proc_info,
    .proc_name      = NAME53C8XX,
#endif
};

static int attach_count;

static int __devinit sym2_probe(struct pci_dev *pdev,
                const struct pci_device_id *ent)
{
    struct sym_device sym_dev;
    struct sym_nvram nvram;
    struct Scsi_Host *shost;
    int do_iounmap = 0;
    int do_disable_device = 1;

    memset(&sym_dev, 0, sizeof(sym_dev));
    memset(&nvram, 0, sizeof(nvram));
    sym_dev.pdev = pdev;
    sym_dev.host_id = SYM_SETUP_HOST_ID;

    if (pci_enable_device(pdev))
        goto leave;

    pci_set_master(pdev);

    if (pci_request_regions(pdev, NAME53C8XX))
        goto disable;

    if (sym_check_supported(&sym_dev))
        goto free;

    if (sym_iomap_device(&sym_dev))
        goto free;
    do_iounmap = 1;

    if (sym_check_raid(&sym_dev)) {
        do_disable_device = 0;  /* Don't disable the device */
        goto free;
    }

    if (sym_set_workarounds(&sym_dev))
        goto free;

    sym_config_pqs(pdev, &sym_dev);

    sym_get_nvram(&sym_dev, &nvram);

    do_iounmap = 0; /* Don't sym_iounmap_device() after sym_attach(). */
    shost = sym_attach(&sym2_template, attach_count, &sym_dev);
    if (!shost)
        goto free;

    if (scsi_add_host(shost, &pdev->dev))
        goto detach;
    scsi_scan_host(shost);

    attach_count++;

    return 0;

 detach:
    sym_detach(pci_get_drvdata(pdev), pdev);
 free:
    if (do_iounmap)
        sym_iounmap_device(&sym_dev);
    pci_release_regions(pdev);
 disable:
    if (do_disable_device)
        pci_disable_device(pdev);
 leave:
    return -ENODEV;
}

static void sym2_remove(struct pci_dev *pdev)
{
    struct Scsi_Host *shost = pci_get_drvdata(pdev);

    scsi_remove_host(shost);
    sym_detach(shost, pdev);
    pci_release_regions(pdev);
    pci_disable_device(pdev);

    attach_count--;
}

static pci_ers_result_t sym2_io_error_detected(struct pci_dev *pdev,
                                         enum pci_channel_state state)
{
    /* If slot is permanently frozen, turn everything off */
    if (state == pci_channel_io_perm_failure) {
        sym2_remove(pdev);
        return PCI_ERS_RESULT_DISCONNECT;
    }

    disable_irq(pdev->irq);
    pci_disable_device(pdev);

    /* Request that MMIO be enabled, so register dump can be taken. */
    return PCI_ERS_RESULT_CAN_RECOVER;
}

static pci_ers_result_t sym2_io_slot_dump(struct pci_dev *pdev)
{
    struct Scsi_Host *shost = pci_get_drvdata(pdev);

    sym_dump_registers(shost);

    /* Request a slot reset. */
    return PCI_ERS_RESULT_NEED_RESET;
}

static void sym2_reset_workarounds(struct pci_dev *pdev)
{
    u_short status_reg;
    struct sym_chip *chip;

    chip = sym_lookup_chip_table(pdev->device, pdev->revision);

    /* Work around for errant bit in 895A, in a fashion
     * similar to what is done in sym_set_workarounds().
     */
    pci_read_config_word(pdev, PCI_STATUS, &status_reg);
    if (!(chip->features & FE_66MHZ) && (status_reg & PCI_STATUS_66MHZ)) {
        status_reg = PCI_STATUS_66MHZ;
        pci_write_config_word(pdev, PCI_STATUS, status_reg);
        pci_read_config_word(pdev, PCI_STATUS, &status_reg);
    }
}

static pci_ers_result_t sym2_io_slot_reset(struct pci_dev *pdev)
{
    struct Scsi_Host *shost = pci_get_drvdata(pdev);
    struct sym_hcb *np = sym_get_hcb(shost);

    printk(KERN_INFO "%s: recovering from a PCI slot reset\n",
              sym_name(np));

    if (pci_enable_device(pdev)) {
        printk(KERN_ERR "%s: Unable to enable after PCI reset\n",
                sym_name(np));
        return PCI_ERS_RESULT_DISCONNECT;
    }

    pci_set_master(pdev);
    enable_irq(pdev->irq);

    /* If the chip can do Memory Write Invalidate, enable it */
    if (np->features & FE_WRIE) {
        if (pci_set_mwi(pdev))
            return PCI_ERS_RESULT_DISCONNECT;
    }

    /* Perform work-arounds, analogous to sym_set_workarounds() */
    sym2_reset_workarounds(pdev);

    /* Perform host reset only on one instance of the card */
    if (PCI_FUNC(pdev->devfn) == 0) {
        if (sym_reset_scsi_bus(np, 0)) {
            printk(KERN_ERR "%s: Unable to reset scsi host\n",
                    sym_name(np));
            return PCI_ERS_RESULT_DISCONNECT;
        }
        sym_start_up(shost, 1);
    }

    return PCI_ERS_RESULT_RECOVERED;
}

static void sym2_io_resume(struct pci_dev *pdev)
{
    struct Scsi_Host *shost = pci_get_drvdata(pdev);
    struct sym_data *sym_data = shost_priv(shost);

    spin_lock_irq(shost->host_lock);
    if (sym_data->io_reset)
        complete_all(sym_data->io_reset);
    spin_unlock_irq(shost->host_lock);
}

static void sym2_get_signalling(struct Scsi_Host *shost)
{
    struct sym_hcb *np = sym_get_hcb(shost);
    enum spi_signal_type type;

    switch (np->scsi_mode) {
    case SMODE_SE:
        type = SPI_SIGNAL_SE;
        break;
    case SMODE_LVD:
        type = SPI_SIGNAL_LVD;
        break;
    case SMODE_HVD:
        type = SPI_SIGNAL_HVD;
        break;
    default:
        type = SPI_SIGNAL_UNKNOWN;
        break;
    }
    spi_signalling(shost) = type;
}

static void sym2_set_offset(struct scsi_target *starget, int offset)
{
    struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
    struct sym_hcb *np = sym_get_hcb(shost);
    struct sym_tcb *tp = &np->target[starget->id];

    tp->tgoal.offset = offset;
    tp->tgoal.check_nego = 1;
}

static void sym2_set_period(struct scsi_target *starget, int period)
{
    struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
    struct sym_hcb *np = sym_get_hcb(shost);
    struct sym_tcb *tp = &np->target[starget->id];

    /* have to have DT for these transfers, but DT will also
     * set width, so check that this is allowed */
    if (period <= np->minsync && spi_width(starget))
        tp->tgoal.dt = 1;

    tp->tgoal.period = period;
    tp->tgoal.check_nego = 1;
}

static void sym2_set_width(struct scsi_target *starget, int width)
{
    struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
    struct sym_hcb *np = sym_get_hcb(shost);
    struct sym_tcb *tp = &np->target[starget->id];

    /* It is illegal to have DT set on narrow transfers.  If DT is
     * clear, we must also clear IU and QAS.  */
    if (width == 0)
        tp->tgoal.iu = tp->tgoal.dt = tp->tgoal.qas = 0;

    tp->tgoal.width = width;
    tp->tgoal.check_nego = 1;
}

static void sym2_set_dt(struct scsi_target *starget, int dt)
{
    struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
    struct sym_hcb *np = sym_get_hcb(shost);
    struct sym_tcb *tp = &np->target[starget->id];

    /* We must clear QAS and IU if DT is clear */
    if (dt)
        tp->tgoal.dt = 1;
    else
        tp->tgoal.iu = tp->tgoal.dt = tp->tgoal.qas = 0;
    tp->tgoal.check_nego = 1;
}

#if 0
static void sym2_set_iu(struct scsi_target *starget, int iu)
{
    struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
    struct sym_hcb *np = sym_get_hcb(shost);
    struct sym_tcb *tp = &np->target[starget->id];

    if (iu)
        tp->tgoal.iu = tp->tgoal.dt = 1;
    else
        tp->tgoal.iu = 0;
    tp->tgoal.check_nego = 1;
}

static void sym2_set_qas(struct scsi_target *starget, int qas)
{
    struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
    struct sym_hcb *np = sym_get_hcb(shost);
    struct sym_tcb *tp = &np->target[starget->id];

    if (qas)
        tp->tgoal.dt = tp->tgoal.qas = 1;
    else
        tp->tgoal.qas = 0;
    tp->tgoal.check_nego = 1;
}
#endif

static struct spi_function_template sym2_transport_functions = {
    .set_offset = sym2_set_offset,
    .show_offset    = 1,
    .set_period = sym2_set_period,
    .show_period    = 1,
    .set_width  = sym2_set_width,
    .show_width = 1,
    .set_dt     = sym2_set_dt,
    .show_dt    = 1,
#if 0
    .set_iu     = sym2_set_iu,
    .show_iu    = 1,
    .set_qas    = sym2_set_qas,
    .show_qas   = 1,
#endif
    .get_signalling = sym2_get_signalling,
};

static struct pci_device_id sym2_id_table[] __devinitdata = {
    { PCI_VENDOR_ID_LSI_LOGIC, PCI_DEVICE_ID_NCR_53C810,
      PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0UL },
    { PCI_VENDOR_ID_LSI_LOGIC, PCI_DEVICE_ID_NCR_53C820,
      PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0UL }, /* new */
    { PCI_VENDOR_ID_LSI_LOGIC, PCI_DEVICE_ID_NCR_53C825,
      PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0UL },
    { PCI_VENDOR_ID_LSI_LOGIC, PCI_DEVICE_ID_NCR_53C815,
      PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0UL },
    { PCI_VENDOR_ID_LSI_LOGIC, PCI_DEVICE_ID_LSI_53C810AP,
      PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0UL }, /* new */
    { PCI_VENDOR_ID_LSI_LOGIC, PCI_DEVICE_ID_NCR_53C860,
      PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0UL },
    { PCI_VENDOR_ID_LSI_LOGIC, PCI_DEVICE_ID_LSI_53C1510,
      PCI_ANY_ID, PCI_ANY_ID, PCI_CLASS_STORAGE_SCSI<<8,  0xffff00, 0UL },
    { PCI_VENDOR_ID_LSI_LOGIC, PCI_DEVICE_ID_NCR_53C896,
      PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0UL },
    { PCI_VENDOR_ID_LSI_LOGIC, PCI_DEVICE_ID_NCR_53C895,
      PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0UL },
    { PCI_VENDOR_ID_LSI_LOGIC, PCI_DEVICE_ID_NCR_53C885,
      PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0UL },
    { PCI_VENDOR_ID_LSI_LOGIC, PCI_DEVICE_ID_NCR_53C875,
      PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0UL },
    { PCI_VENDOR_ID_LSI_LOGIC, PCI_DEVICE_ID_NCR_53C1510,
      PCI_ANY_ID, PCI_ANY_ID,  PCI_CLASS_STORAGE_SCSI<<8,  0xffff00, 0UL }, /* new */
    { PCI_VENDOR_ID_LSI_LOGIC, PCI_DEVICE_ID_LSI_53C895A,
      PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0UL },
    { PCI_VENDOR_ID_LSI_LOGIC, PCI_DEVICE_ID_LSI_53C875A,
      PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0UL },
    { PCI_VENDOR_ID_LSI_LOGIC, PCI_DEVICE_ID_LSI_53C1010_33,
      PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0UL },
    { PCI_VENDOR_ID_LSI_LOGIC, PCI_DEVICE_ID_LSI_53C1010_66,
      PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0UL },
    { PCI_VENDOR_ID_LSI_LOGIC, PCI_DEVICE_ID_NCR_53C875J,
      PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0UL },
    { 0, }
};

MODULE_DEVICE_TABLE(pci, sym2_id_table);

static const struct pci_error_handlers sym2_err_handler = {
    .error_detected = sym2_io_error_detected,
    .mmio_enabled   = sym2_io_slot_dump,
    .slot_reset = sym2_io_slot_reset,
    .resume     = sym2_io_resume,
};

static struct pci_driver sym2_driver = {
    .name       = NAME53C8XX,
    .id_table   = sym2_id_table,
    .probe      = sym2_probe,
    .remove     = sym2_remove,
    .err_handler    = &sym2_err_handler,
};

static int __init sym2_init(void)
{
    int error;

    sym2_setup_params();
    sym2_transport_template = spi_attach_transport(&sym2_transport_functions);
    if (!sym2_transport_template)
        return -ENODEV;

    error = pci_register_driver(&sym2_driver);
    if (error)
        spi_release_transport(sym2_transport_template);
    return error;
}

static void __exit sym2_exit(void)
{
    pci_unregister_driver(&sym2_driver);
    spi_release_transport(sym2_transport_template);
}

module_init(sym2_init);
module_exit(sym2_exit);