/*
 * Device driver for the SYMBIOS/LSILOGIC 53C8XX and 53C1010 family 
 * of PCI-SCSI IO processors.
 *
 * Copyright (C) 1999-2001  Gerard Roudier <groudier@free.fr>
 * Copyright (c) 2003-2005  Matthew Wilcox <matthew@wil.cx>
 *
 * 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        <wolf@cologne.de>
 *         Stefan Esser                <se@mi.Uni-Koeln.de>
 * Copyright (C) 1994  Wolfgang Stanglmeier
 *
 * Other major contributions:
 *
 * NVRAM detection and reading.
 * Copyright (C) 1997 Richard Waltham <dormouse@farsrobt.demon.co.uk>
 *
 *-----------------------------------------------------------------------------
 *
 * 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 <matthew@wil.cx>");
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 */


/*
 *  Copy formatted information into the input buffer.
 */
static int sym_show_info(struct seq_file *m, struct Scsi_Host *shost)
{
#ifdef SYM_LINUX_USER_INFO_SUPPORT
        struct sym_data *sym_data = shost_priv(shost);
        struct pci_dev *pdev = sym_data->pdev;
        struct sym_hcb *np = sym_data->ncb;

        seq_printf(m, "Chip " NAME53C "%s, device id 0x%x, "
                 "revision id 0x%x\n", np->s.chip_name,
                 pdev->device, pdev->revision);
        seq_printf(m, "At PCI address %s, IRQ %u\n",
                         pci_name(pdev), pdev->irq);
        seq_printf(m, "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" : "");

        seq_printf(m, "Max. started commands %d, "
                 "max. commands per LUN %d\n",
                 SYM_CONF_MAX_START, SYM_CONF_MAX_TAG);

        return 0;
#else
        return -EINVAL;
#endif /* SYM_LINUX_USER_INFO_SUPPORT */
}

#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 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 *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 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 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 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 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 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
        .show_info              = sym_show_info,
#ifdef  SYM_LINUX_USER_COMMAND_SUPPORT
        .write_info             = sym_user_command,
#endif
        .proc_name              = NAME53C8XX,
#endif
};

static int attach_count;

static int 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--;
}

/**
 * sym2_io_error_detected() - called when PCI error is detected
 * @pdev: pointer to PCI device
 * @state: current state of the PCI slot
 */
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;
}

/**
 * sym2_io_slot_dump - Enable MMIO and dump debug registers
 * @pdev: pointer to PCI device
 */
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;
}

/**
 * sym2_reset_workarounds - hardware-specific work-arounds
 *
 * This routine is similar to sym_set_workarounds(), except
 * that, at this point, we already know that the device was
 * successfully initialized at least once before, and so most
 * of the steps taken there are un-needed here.
 */
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);
        }
}

/**
 * sym2_io_slot_reset() - called when the pci bus has been reset.
 * @pdev: pointer to PCI device
 *
 * Restart the card from scratch.
 */
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;
}

/**
 * sym2_io_resume() - resume normal ops after PCI reset
 * @pdev: pointer to PCI device
 *
 * Called when the error recovery driver tells us that its
 * OK to resume normal operation. Use completion to allow
 * halted scsi ops to resume.
 */
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[] = {
        { 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);