// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/drivers/acorn/scsi/fas216.c
 *
 *  Copyright (C) 1997-2003 Russell King
 *
 * Based on information in qlogicfas.c by Tom Zerucha, Michael Griffith, and
 * other sources, including:
 *   the AMD Am53CF94 data sheet
 *   the AMD Am53C94 data sheet
 *
 * This is a generic driver.  To use it, have a look at cumana_2.c.  You
 * should define your own structure that overlays FAS216_Info, eg:
 * struct my_host_data {
 *    FAS216_Info info;
 *    ... my host specific data ...
 * };
 *
 * Changelog:
 *  30-08-1997  RMK     Created
 *  14-09-1997  RMK     Started disconnect support
 *  08-02-1998  RMK     Corrected real DMA support
 *  15-02-1998  RMK     Started sync xfer support
 *  06-04-1998  RMK     Tightened conditions for printing incomplete
 *                      transfers
 *  02-05-1998  RMK     Added extra checks in fas216_reset
 *  24-05-1998  RMK     Fixed synchronous transfers with period >= 200ns
 *  27-06-1998  RMK     Changed asm/delay.h to linux/delay.h
 *  26-08-1998  RMK     Improved message support wrt MESSAGE_REJECT
 *  02-04-2000  RMK     Converted to use the new error handling, and
 *                      automatically request sense data upon check
 *                      condition status from targets.
 */
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/ioport.h>
#include <linux/proc_fs.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/interrupt.h>

#include <asm/dma.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/ecard.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_tcq.h>
#include "fas216.h"
#include "arm_scsi.h"

/* NOTE: SCSI2 Synchronous transfers *require* DMA according to
 *  the data sheet.  This restriction is crazy, especially when
 *  you only want to send 16 bytes!  What were the guys who
 *  designed this chip on at that time?  Did they read the SCSI2
 *  spec at all?  The following sections are taken from the SCSI2
 *  standard (s2r10) concerning this:
 *
 * > IMPLEMENTORS NOTES:
 * >   (1)  Re-negotiation at every selection is not recommended, since a
 * >   significant performance impact is likely.
 *
 * >  The implied synchronous agreement shall remain in effect until a BUS DEVICE
 * >  RESET message is received, until a hard reset condition occurs, or until one
 * >  of the two SCSI devices elects to modify the agreement.  The default data
 * >  transfer mode is asynchronous data transfer mode.  The default data transfer
 * >  mode is entered at power on, after a BUS DEVICE RESET message, or after a hard
 * >  reset condition.
 *
 *  In total, this means that once you have elected to use synchronous
 *  transfers, you must always use DMA.
 *
 *  I was thinking that this was a good chip until I found this restriction ;(
 */
#define SCSI2_SYNC

#undef DEBUG_CONNECT
#undef DEBUG_MESSAGES

#undef CHECK_STRUCTURE

#define LOG_CONNECT             (1 << 0)
#define LOG_BUSSERVICE          (1 << 1)
#define LOG_FUNCTIONDONE        (1 << 2)
#define LOG_MESSAGES            (1 << 3)
#define LOG_BUFFER              (1 << 4)
#define LOG_ERROR               (1 << 8)

static int level_mask = LOG_ERROR;

module_param(level_mask, int, 0644);

#ifndef MODULE
static int __init fas216_log_setup(char *str)
{
        char *s;

        level_mask = 0;

        while ((s = strsep(&str, ",")) != NULL) {
                switch (s[0]) {
                case 'a':
                        if (strcmp(s, "all") == 0)
                                level_mask |= -1;
                        break;
                case 'b':
                        if (strncmp(s, "bus", 3) == 0)
                                level_mask |= LOG_BUSSERVICE;
                        if (strncmp(s, "buf", 3) == 0)
                                level_mask |= LOG_BUFFER;
                        break;
                case 'c':
                        level_mask |= LOG_CONNECT;
                        break;
                case 'e':
                        level_mask |= LOG_ERROR;
                        break;
                case 'm':
                        level_mask |= LOG_MESSAGES;
                        break;
                case 'n':
                        if (strcmp(s, "none") == 0)
                                level_mask = 0;
                        break;
                case 's':
                        level_mask |= LOG_FUNCTIONDONE;
                        break;
                }
        }
        return 1;
}

__setup("fas216_logging=", fas216_log_setup);
#endif

static inline unsigned char fas216_readb(FAS216_Info *info, unsigned int reg)
{
        unsigned int off = reg << info->scsi.io_shift;
        return readb(info->scsi.io_base + off);
}

static inline void fas216_writeb(FAS216_Info *info, unsigned int reg, unsigned int val)
{
        unsigned int off = reg << info->scsi.io_shift;
        writeb(val, info->scsi.io_base + off);
}

static void fas216_dumpstate(FAS216_Info *info)
{
        unsigned char is, stat, inst;

        is   = fas216_readb(info, REG_IS);
        stat = fas216_readb(info, REG_STAT);
        inst = fas216_readb(info, REG_INST);
        
        printk("FAS216: CTCL=%02X CTCM=%02X CMD=%02X STAT=%02X"
               " INST=%02X IS=%02X CFIS=%02X",
                fas216_readb(info, REG_CTCL),
                fas216_readb(info, REG_CTCM),
                fas216_readb(info, REG_CMD),  stat, inst, is,
                fas216_readb(info, REG_CFIS));
        printk(" CNTL1=%02X CNTL2=%02X CNTL3=%02X CTCH=%02X\n",
                fas216_readb(info, REG_CNTL1),
                fas216_readb(info, REG_CNTL2),
                fas216_readb(info, REG_CNTL3),
                fas216_readb(info, REG_CTCH));
}

static void print_SCp(struct scsi_pointer *SCp, const char *prefix, const char *suffix)
{
        printk("%sptr %p this_residual 0x%x buffer %p buffers_residual 0x%x%s",
                prefix, SCp->ptr, SCp->this_residual, SCp->buffer,
                SCp->buffers_residual, suffix);
}

#ifdef CHECK_STRUCTURE
static void fas216_dumpinfo(FAS216_Info *info)
{
        static int used = 0;
        int i;

        if (used++)
                return;

        printk("FAS216_Info=\n");
        printk("  { magic_start=%lX host=%p SCpnt=%p origSCpnt=%p\n",
                info->magic_start, info->host, info->SCpnt,
                info->origSCpnt);
        printk("    scsi={ io_shift=%X irq=%X cfg={ %X %X %X %X }\n",
                info->scsi.io_shift, info->scsi.irq,
                info->scsi.cfg[0], info->scsi.cfg[1], info->scsi.cfg[2],
                info->scsi.cfg[3]);
        printk("           type=%p phase=%X\n",
                info->scsi.type, info->scsi.phase);
        print_SCp(&info->scsi.SCp, "           SCp={ ", " }\n");
        printk("      msgs async_stp=%X disconnectable=%d aborting=%d }\n",
                info->scsi.async_stp,
                info->scsi.disconnectable, info->scsi.aborting);
        printk("    stats={ queues=%X removes=%X fins=%X reads=%X writes=%X miscs=%X\n"
               "            disconnects=%X aborts=%X bus_resets=%X host_resets=%X}\n",
                info->stats.queues, info->stats.removes, info->stats.fins,
                info->stats.reads, info->stats.writes, info->stats.miscs,
                info->stats.disconnects, info->stats.aborts, info->stats.bus_resets,
                info->stats.host_resets);
        printk("    ifcfg={ clockrate=%X select_timeout=%X asyncperiod=%X sync_max_depth=%X }\n",
                info->ifcfg.clockrate, info->ifcfg.select_timeout,
                info->ifcfg.asyncperiod, info->ifcfg.sync_max_depth);
        for (i = 0; i < 8; i++) {
                printk("    busyluns[%d]=%08lx dev[%d]={ disconnect_ok=%d stp=%X sof=%X sync_state=%X }\n",
                        i, info->busyluns[i], i,
                        info->device[i].disconnect_ok, info->device[i].stp,
                        info->device[i].sof, info->device[i].sync_state);
        }
        printk("    dma={ transfer_type=%X setup=%p pseudo=%p stop=%p }\n",
                info->dma.transfer_type, info->dma.setup,
                info->dma.pseudo, info->dma.stop);
        printk("    internal_done=%X magic_end=%lX }\n",
                info->internal_done, info->magic_end);
}

static void __fas216_checkmagic(FAS216_Info *info, const char *func)
{
        int corruption = 0;
        if (info->magic_start != MAGIC) {
                printk(KERN_CRIT "FAS216 Error: magic at start corrupted\n");
                corruption++;
        }
        if (info->magic_end != MAGIC) {
                printk(KERN_CRIT "FAS216 Error: magic at end corrupted\n");
                corruption++;
        }
        if (corruption) {
                fas216_dumpinfo(info);
                panic("scsi memory space corrupted in %s", func);
        }
}
#define fas216_checkmagic(info) __fas216_checkmagic((info), __func__)
#else
#define fas216_checkmagic(info)
#endif

static const char *fas216_bus_phase(int stat)
{
        static const char *phases[] = {
                "DATA OUT", "DATA IN",
                "COMMAND", "STATUS",
                "MISC OUT", "MISC IN",
                "MESG OUT", "MESG IN"
        };

        return phases[stat & STAT_BUSMASK];
}

static const char *fas216_drv_phase(FAS216_Info *info)
{
        static const char *phases[] = {
                [PHASE_IDLE]            = "idle",
                [PHASE_SELECTION]       = "selection",
                [PHASE_COMMAND]         = "command",
                [PHASE_DATAOUT]         = "data out",
                [PHASE_DATAIN]          = "data in",
                [PHASE_MSGIN]           = "message in",
                [PHASE_MSGIN_DISCONNECT]= "disconnect",
                [PHASE_MSGOUT_EXPECT]   = "expect message out",
                [PHASE_MSGOUT]          = "message out",
                [PHASE_STATUS]          = "status",
                [PHASE_DONE]            = "done",
        };

        if (info->scsi.phase < ARRAY_SIZE(phases) &&
            phases[info->scsi.phase])
                return phases[info->scsi.phase];
        return "???";
}

static char fas216_target(FAS216_Info *info)
{
        if (info->SCpnt)
                return '0' + info->SCpnt->device->id;
        else
                return 'H';
}

static void
fas216_do_log(FAS216_Info *info, char target, char *fmt, va_list ap)
{
        static char buf[1024];

        vsnprintf(buf, sizeof(buf), fmt, ap);
        printk("scsi%d.%c: %s", info->host->host_no, target, buf);
}

static void fas216_log_command(FAS216_Info *info, int level,
                               struct scsi_cmnd *SCpnt, char *fmt, ...)
{
        va_list args;

        if (level != 0 && !(level & level_mask))
                return;

        va_start(args, fmt);
        fas216_do_log(info, '0' + SCpnt->device->id, fmt, args);
        va_end(args);

        scsi_print_command(SCpnt);
}

static void
fas216_log_target(FAS216_Info *info, int level, int target, char *fmt, ...)
{
        va_list args;

        if (level != 0 && !(level & level_mask))
                return;

        if (target < 0)
                target = 'H';
        else
                target += '0';

        va_start(args, fmt);
        fas216_do_log(info, target, fmt, args);
        va_end(args);

        printk("\n");
}

static void fas216_log(FAS216_Info *info, int level, char *fmt, ...)
{
        va_list args;

        if (level != 0 && !(level & level_mask))
                return;

        va_start(args, fmt);
        fas216_do_log(info, fas216_target(info), fmt, args);
        va_end(args);

        printk("\n");
}

#define PH_SIZE 32

static struct { int stat, ssr, isr, ph; } ph_list[PH_SIZE];
static int ph_ptr;

static void add_debug_list(int stat, int ssr, int isr, int ph)
{
        ph_list[ph_ptr].stat = stat;
        ph_list[ph_ptr].ssr = ssr;
        ph_list[ph_ptr].isr = isr;
        ph_list[ph_ptr].ph = ph;

        ph_ptr = (ph_ptr + 1) & (PH_SIZE-1);
}

static struct { int command; void *from; } cmd_list[8];
static int cmd_ptr;

static void fas216_cmd(FAS216_Info *info, unsigned int command)
{
        cmd_list[cmd_ptr].command = command;
        cmd_list[cmd_ptr].from = __builtin_return_address(0);

        cmd_ptr = (cmd_ptr + 1) & 7;

        fas216_writeb(info, REG_CMD, command);
}

static void print_debug_list(void)
{
        int i;

        i = ph_ptr;

        printk(KERN_ERR "SCSI IRQ trail\n");
        do {
                printk(" %02x:%02x:%02x:%1x",
                        ph_list[i].stat, ph_list[i].ssr,
                        ph_list[i].isr, ph_list[i].ph);
                i = (i + 1) & (PH_SIZE - 1);
                if (((i ^ ph_ptr) & 7) == 0)
                        printk("\n");
        } while (i != ph_ptr);
        if ((i ^ ph_ptr) & 7)
                printk("\n");

        i = cmd_ptr;
        printk(KERN_ERR "FAS216 commands: ");
        do {
                printk("%02x:%p ", cmd_list[i].command, cmd_list[i].from);
                i = (i + 1) & 7;
        } while (i != cmd_ptr);
        printk("\n");
}

static void fas216_done(FAS216_Info *info, unsigned int result);

/**
 * fas216_get_last_msg - retrive last message from the list
 * @info: interface to search
 * @pos: current fifo position
 *
 * Retrieve a last message from the list, using position in fifo.
 */
static inline unsigned short
fas216_get_last_msg(FAS216_Info *info, int pos)
{
        unsigned short packed_msg = NOP;
        struct message *msg;
        int msgnr = 0;

        while ((msg = msgqueue_getmsg(&info->scsi.msgs, msgnr++)) != NULL) {
                if (pos >= msg->fifo)
                        break;
        }

        if (msg) {
                if (msg->msg[0] == EXTENDED_MESSAGE)
                        packed_msg = EXTENDED_MESSAGE | msg->msg[2] << 8;
                else
                        packed_msg = msg->msg[0];
        }

        fas216_log(info, LOG_MESSAGES,
                "Message: %04x found at position %02x\n", packed_msg, pos);

        return packed_msg;
}

/**
 * fas216_syncperiod - calculate STP register value
 * @info: state structure for interface connected to device
 * @ns: period in ns (between subsequent bytes)
 *
 * Calculate value to be loaded into the STP register for a given period
 * in ns. Returns a value suitable for REG_STP.
 */
static int fas216_syncperiod(FAS216_Info *info, int ns)
{
        int value = (info->ifcfg.clockrate * ns) / 1000;

        fas216_checkmagic(info);

        if (value < 4)
                value = 4;
        else if (value > 35)
                value = 35;

        return value & 31;
}

/**
 * fas216_set_sync - setup FAS216 chip for specified transfer period.
 * @info: state structure for interface connected to device
 * @target: target
 *
 * Correctly setup FAS216 chip for specified transfer period.
 * Notes   : we need to switch the chip out of FASTSCSI mode if we have
 *           a transfer period >= 200ns - otherwise the chip will violate
 *           the SCSI timings.
 */
static void fas216_set_sync(FAS216_Info *info, int target)
{
        unsigned int cntl3;

        fas216_writeb(info, REG_SOF, info->device[target].sof);
        fas216_writeb(info, REG_STP, info->device[target].stp);

        cntl3 = info->scsi.cfg[2];
        if (info->device[target].period >= (200 / 4))
                cntl3 = cntl3 & ~CNTL3_FASTSCSI;

        fas216_writeb(info, REG_CNTL3, cntl3);
}

/* Synchronous transfer support
 *
 * Note: The SCSI II r10 spec says (5.6.12):
 *
 *  (2)  Due to historical problems with early host adapters that could
 *  not accept an SDTR message, some targets may not initiate synchronous
 *  negotiation after a power cycle as required by this standard.  Host
 *  adapters that support synchronous mode may avoid the ensuing failure
 *  modes when the target is independently power cycled by initiating a
 *  synchronous negotiation on each REQUEST SENSE and INQUIRY command.
 *  This approach increases the SCSI bus overhead and is not recommended
 *  for new implementations.  The correct method is to respond to an
 *  SDTR message with a MESSAGE REJECT message if the either the
 *  initiator or target devices does not support synchronous transfers
 *  or does not want to negotiate for synchronous transfers at the time.
 *  Using the correct method assures compatibility with wide data
 *  transfers and future enhancements.
 *
 * We will always initiate a synchronous transfer negotiation request on
 * every INQUIRY or REQUEST SENSE message, unless the target itself has
 * at some point performed a synchronous transfer negotiation request, or
 * we have synchronous transfers disabled for this device.
 */

/**
 * fas216_handlesync - Handle a synchronous transfer message
 * @info: state structure for interface
 * @msg: message from target
 *
 * Handle a synchronous transfer message from the target
 */
static void fas216_handlesync(FAS216_Info *info, char *msg)
{
        struct fas216_device *dev = &info->device[info->SCpnt->device->id];
        enum { sync, async, none, reject } res = none;

#ifdef SCSI2_SYNC
        switch (msg[0]) {
        case MESSAGE_REJECT:
                /* Synchronous transfer request failed.
                 * Note: SCSI II r10:
                 *
                 *  SCSI devices that are capable of synchronous
                 *  data transfers shall not respond to an SDTR
                 *  message with a MESSAGE REJECT message.
                 *
                 * Hence, if we get this condition, we disable
                 * negotiation for this device.
                 */
                if (dev->sync_state == neg_inprogress) {
                        dev->sync_state = neg_invalid;
                        res = async;
                }
                break;

        case EXTENDED_MESSAGE:
                switch (dev->sync_state) {
                /* We don't accept synchronous transfer requests.
                 * Respond with a MESSAGE_REJECT to prevent a
                 * synchronous transfer agreement from being reached.
                 */
                case neg_invalid:
                        res = reject;
                        break;

                /* We were not negotiating a synchronous transfer,
                 * but the device sent us a negotiation request.
                 * Honour the request by sending back a SDTR
                 * message containing our capability, limited by
                 * the targets capability.
                 */
                default:
                        fas216_cmd(info, CMD_SETATN);
                        if (msg[4] > info->ifcfg.sync_max_depth)
                                msg[4] = info->ifcfg.sync_max_depth;
                        if (msg[3] < 1000 / info->ifcfg.clockrate)
                                msg[3] = 1000 / info->ifcfg.clockrate;

                        msgqueue_flush(&info->scsi.msgs);
                        msgqueue_addmsg(&info->scsi.msgs, 5,
                                        EXTENDED_MESSAGE, 3, EXTENDED_SDTR,
                                        msg[3], msg[4]);
                        info->scsi.phase = PHASE_MSGOUT_EXPECT;

                        /* This is wrong.  The agreement is not in effect
                         * until this message is accepted by the device
                         */
                        dev->sync_state = neg_targcomplete;
                        res = sync;
                        break;

                /* We initiated the synchronous transfer negotiation,
                 * and have successfully received a response from the
                 * target.  The synchronous transfer agreement has been
                 * reached.  Note: if the values returned are out of our
                 * bounds, we must reject the message.
                 */
                case neg_inprogress:
                        res = reject;
                        if (msg[4] <= info->ifcfg.sync_max_depth &&
                            msg[3] >= 1000 / info->ifcfg.clockrate) {
                                dev->sync_state = neg_complete;
                                res = sync;
                        }
                        break;
                }
        }
#else
        res = reject;
#endif

        switch (res) {
        case sync:
                dev->period = msg[3];
                dev->sof    = msg[4];
                dev->stp    = fas216_syncperiod(info, msg[3] * 4);
                fas216_set_sync(info, info->SCpnt->device->id);
                break;

        case reject:
                fas216_cmd(info, CMD_SETATN);
                msgqueue_flush(&info->scsi.msgs);
                msgqueue_addmsg(&info->scsi.msgs, 1, MESSAGE_REJECT);
                info->scsi.phase = PHASE_MSGOUT_EXPECT;
                fallthrough;

        case async:
                dev->period = info->ifcfg.asyncperiod / 4;
                dev->sof    = 0;
                dev->stp    = info->scsi.async_stp;
                fas216_set_sync(info, info->SCpnt->device->id);
                break;

        case none:
                break;
        }
}

/**
 * fas216_updateptrs - update data pointers after transfer suspended/paused
 * @info: interface's local pointer to update
 * @bytes_transferred: number of bytes transferred
 *
 * Update data pointers after transfer suspended/paused
 */
static void fas216_updateptrs(FAS216_Info *info, int bytes_transferred)
{
        struct scsi_pointer *SCp = &info->scsi.SCp;

        fas216_checkmagic(info);

        BUG_ON(bytes_transferred < 0);

        SCp->phase -= bytes_transferred;

        while (bytes_transferred != 0) {
                if (SCp->this_residual > bytes_transferred)
                        break;
                /*
                 * We have used up this buffer.  Move on to the
                 * next buffer.
                 */
                bytes_transferred -= SCp->this_residual;
                if (!next_SCp(SCp) && bytes_transferred) {
                        printk(KERN_WARNING "scsi%d.%c: out of buffers\n",
                                info->host->host_no, '0' + info->SCpnt->device->id);
                        return;
                }
        }

        SCp->this_residual -= bytes_transferred;
        if (SCp->this_residual)
                SCp->ptr += bytes_transferred;
        else
                SCp->ptr = NULL;
}

/**
 * fas216_pio - transfer data off of/on to card using programmed IO
 * @info: interface to transfer data to/from
 * @direction: direction to transfer data (DMA_OUT/DMA_IN)
 *
 * Transfer data off of/on to card using programmed IO.
 * Notes: this is incredibly slow.
 */
static void fas216_pio(FAS216_Info *info, fasdmadir_t direction)
{
        struct scsi_pointer *SCp = &info->scsi.SCp;

        fas216_checkmagic(info);

        if (direction == DMA_OUT)
                fas216_writeb(info, REG_FF, get_next_SCp_byte(SCp));
        else
                put_next_SCp_byte(SCp, fas216_readb(info, REG_FF));

        if (SCp->this_residual == 0)
                next_SCp(SCp);
}

static void fas216_set_stc(FAS216_Info *info, unsigned int length)
{
        fas216_writeb(info, REG_STCL, length);
        fas216_writeb(info, REG_STCM, length >> 8);
        fas216_writeb(info, REG_STCH, length >> 16);
}

static unsigned int fas216_get_ctc(FAS216_Info *info)
{
        return fas216_readb(info, REG_CTCL) +
               (fas216_readb(info, REG_CTCM) << 8) +
               (fas216_readb(info, REG_CTCH) << 16);
}

/**
 * fas216_cleanuptransfer - clean up after a transfer has completed.
 * @info: interface to clean up
 *
 * Update the data pointers according to the number of bytes transferred
 * on the SCSI bus.
 */
static void fas216_cleanuptransfer(FAS216_Info *info)
{
        unsigned long total, residual, fifo;
        fasdmatype_t dmatype = info->dma.transfer_type;

        info->dma.transfer_type = fasdma_none;

        /*
         * PIO transfers do not need to be cleaned up.
         */
        if (dmatype == fasdma_pio || dmatype == fasdma_none)
                return;

        if (dmatype == fasdma_real_all)
                total = info->scsi.SCp.phase;
        else
                total = info->scsi.SCp.this_residual;

        residual = fas216_get_ctc(info);

        fifo = fas216_readb(info, REG_CFIS) & CFIS_CF;

        fas216_log(info, LOG_BUFFER, "cleaning up from previous "
                   "transfer: length 0x%06x, residual 0x%x, fifo %d",
                   total, residual, fifo);

        /*
         * If we were performing Data-Out, the transfer counter
         * counts down each time a byte is transferred by the
         * host to the FIFO.  This means we must include the
         * bytes left in the FIFO from the transfer counter.
         */
        if (info->scsi.phase == PHASE_DATAOUT)
                residual += fifo;

        fas216_updateptrs(info, total - residual);
}

/**
 * fas216_transfer - Perform a DMA/PIO transfer off of/on to card
 * @info: interface from which device disconnected from
 *
 * Start a DMA/PIO transfer off of/on to card
 */
static void fas216_transfer(FAS216_Info *info)
{
        fasdmadir_t direction;
        fasdmatype_t dmatype;

        fas216_log(info, LOG_BUFFER,
                   "starttransfer: buffer %p length 0x%06x reqlen 0x%06x",
                   info->scsi.SCp.ptr, info->scsi.SCp.this_residual,
                   info->scsi.SCp.phase);

        if (!info->scsi.SCp.ptr) {
                fas216_log(info, LOG_ERROR, "null buffer passed to "
                           "fas216_starttransfer");
                print_SCp(&info->scsi.SCp, "SCp: ", "\n");
                print_SCp(arm_scsi_pointer(info->SCpnt), "Cmnd SCp: ", "\n");
                return;
        }

        /*
         * If we have a synchronous transfer agreement in effect, we must
         * use DMA mode.  If we are using asynchronous transfers, we may
         * use DMA mode or PIO mode.
         */
        if (info->device[info->SCpnt->device->id].sof)
                dmatype = fasdma_real_all;
        else
                dmatype = fasdma_pio;

        if (info->scsi.phase == PHASE_DATAOUT)
                direction = DMA_OUT;
        else
                direction = DMA_IN;

        if (info->dma.setup)
                dmatype = info->dma.setup(info->host, &info->scsi.SCp,
                                          direction, dmatype);
        info->dma.transfer_type = dmatype;

        if (dmatype == fasdma_real_all)
                fas216_set_stc(info, info->scsi.SCp.phase);
        else
                fas216_set_stc(info, info->scsi.SCp.this_residual);

        switch (dmatype) {
        case fasdma_pio:
                fas216_log(info, LOG_BUFFER, "PIO transfer");
                fas216_writeb(info, REG_SOF, 0);
                fas216_writeb(info, REG_STP, info->scsi.async_stp);
                fas216_cmd(info, CMD_TRANSFERINFO);
                fas216_pio(info, direction);
                break;

        case fasdma_pseudo:
                fas216_log(info, LOG_BUFFER, "pseudo transfer");
                fas216_cmd(info, CMD_TRANSFERINFO | CMD_WITHDMA);
                info->dma.pseudo(info->host, &info->scsi.SCp,
                                 direction, info->SCpnt->transfersize);
                break;

        case fasdma_real_block:
                fas216_log(info, LOG_BUFFER, "block dma transfer");
                fas216_cmd(info, CMD_TRANSFERINFO | CMD_WITHDMA);
                break;

        case fasdma_real_all:
                fas216_log(info, LOG_BUFFER, "total dma transfer");
                fas216_cmd(info, CMD_TRANSFERINFO | CMD_WITHDMA);
                break;

        default:
                fas216_log(info, LOG_BUFFER | LOG_ERROR,
                           "invalid FAS216 DMA type");
                break;
        }
}

/**
 * fas216_stoptransfer - Stop a DMA transfer onto / off of the card
 * @info: interface from which device disconnected from
 *
 * Called when we switch away from DATA IN or DATA OUT phases.
 */
static void fas216_stoptransfer(FAS216_Info *info)
{
        fas216_checkmagic(info);

        if (info->dma.transfer_type == fasdma_real_all ||
            info->dma.transfer_type == fasdma_real_block)
                info->dma.stop(info->host, &info->scsi.SCp);

        fas216_cleanuptransfer(info);

        if (info->scsi.phase == PHASE_DATAIN) {
                unsigned int fifo;

                /*
                 * If we were performing Data-In, then the FIFO counter
                 * contains the number of bytes not transferred via DMA
                 * from the on-board FIFO.  Read them manually.
                 */
                fifo = fas216_readb(info, REG_CFIS) & CFIS_CF;
                while (fifo && info->scsi.SCp.ptr) {
                        *info->scsi.SCp.ptr = fas216_readb(info, REG_FF);
                        fas216_updateptrs(info, 1);
                        fifo--;
                }
        } else {
                /*
                 * After a Data-Out phase, there may be unsent
                 * bytes left in the FIFO.  Flush them out.
                 */
                fas216_cmd(info, CMD_FLUSHFIFO);
        }
}

static void fas216_aborttransfer(FAS216_Info *info)
{
        fas216_checkmagic(info);

        if (info->dma.transfer_type == fasdma_real_all ||
            info->dma.transfer_type == fasdma_real_block)
                info->dma.stop(info->host, &info->scsi.SCp);

        info->dma.transfer_type = fasdma_none;
        fas216_cmd(info, CMD_FLUSHFIFO);
}

static void fas216_kick(FAS216_Info *info);

/**
 * fas216_disconnected_intr - handle device disconnection
 * @info: interface from which device disconnected from
 *
 * Handle device disconnection
 */
static void fas216_disconnect_intr(FAS216_Info *info)
{
        unsigned long flags;

        fas216_checkmagic(info);

        fas216_log(info, LOG_CONNECT, "disconnect phase=%02x",
                   info->scsi.phase);

        msgqueue_flush(&info->scsi.msgs);

        switch (info->scsi.phase) {
        case PHASE_SELECTION:                   /* while selecting - no target          */
        case PHASE_SELSTEPS:
                fas216_done(info, DID_NO_CONNECT);
                break;

        case PHASE_MSGIN_DISCONNECT:            /* message in - disconnecting           */
                info->scsi.disconnectable = 1;
                info->scsi.phase = PHASE_IDLE;
                info->stats.disconnects += 1;
                spin_lock_irqsave(&info->host_lock, flags);
                if (info->scsi.phase == PHASE_IDLE)
                        fas216_kick(info);
                spin_unlock_irqrestore(&info->host_lock, flags);
                break;

        case PHASE_DONE:                        /* at end of command - complete         */
                fas216_done(info, DID_OK);
                break;

        case PHASE_MSGOUT:                      /* message out - possible ABORT message */
                if (fas216_get_last_msg(info, info->scsi.msgin_fifo) == ABORT) {
                        info->scsi.aborting = 0;
                        fas216_done(info, DID_ABORT);
                        break;
                }
                fallthrough;

        default:                                /* huh?                                 */
                printk(KERN_ERR "scsi%d.%c: unexpected disconnect in phase %s\n",
                        info->host->host_no, fas216_target(info), fas216_drv_phase(info));
                print_debug_list();
                fas216_stoptransfer(info);
                fas216_done(info, DID_ERROR);
                break;
        }
}

/**
 * fas216_reselected_intr - start reconnection of a device
 * @info: interface which was reselected
 *
 * Start reconnection of a device
 */
static void
fas216_reselected_intr(FAS216_Info *info)
{
        unsigned int cfis, i;
        unsigned char msg[4];
        unsigned char target, lun, tag;

        fas216_checkmagic(info);

        WARN_ON(info->scsi.phase == PHASE_SELECTION ||
                info->scsi.phase == PHASE_SELSTEPS);

        cfis = fas216_readb(info, REG_CFIS);

        fas216_log(info, LOG_CONNECT, "reconnect phase=%02x cfis=%02x",
                   info->scsi.phase, cfis);

        cfis &= CFIS_CF;

        if (cfis < 2 || cfis > 4) {
                printk(KERN_ERR "scsi%d.H: incorrect number of bytes after reselect\n",
                        info->host->host_no);
                goto bad_message;
        }

        for (i = 0; i < cfis; i++)
                msg[i] = fas216_readb(info, REG_FF);

        if (!(msg[0] & (1 << info->host->this_id)) ||
            !(msg[1] & 0x80))
                goto initiator_error;

        target = msg[0] & ~(1 << info->host->this_id);
        target = ffs(target) - 1;
        lun = msg[1] & 7;
        tag = 0;

        if (cfis >= 3) {
                if (msg[2] != SIMPLE_QUEUE_TAG)
                        goto initiator_error;

                tag = msg[3];
        }

        /* set up for synchronous transfers */
        fas216_writeb(info, REG_SDID, target);
        fas216_set_sync(info, target);
        msgqueue_flush(&info->scsi.msgs);

        fas216_log(info, LOG_CONNECT, "Reconnected: target %1x lun %1x tag %02x",
                   target, lun, tag);

        if (info->scsi.disconnectable && info->SCpnt) {
                info->scsi.disconnectable = 0;
                if (info->SCpnt->device->id  == target &&
                    info->SCpnt->device->lun == lun &&
                    scsi_cmd_to_rq(info->SCpnt)->tag == tag) {
                        fas216_log(info, LOG_CONNECT, "reconnected previously executing command");
                } else {
                        queue_add_cmd_tail(&info->queues.disconnected, info->SCpnt);
                        fas216_log(info, LOG_CONNECT, "had to move command to disconnected queue");
                        info->SCpnt = NULL;
                }
        }
        if (!info->SCpnt) {
                info->SCpnt = queue_remove_tgtluntag(&info->queues.disconnected,
                                        target, lun, tag);
                fas216_log(info, LOG_CONNECT, "had to get command");
        }

        if (info->SCpnt) {
                /*
                 * Restore data pointer from SAVED data pointer
                 */
                info->scsi.SCp = *arm_scsi_pointer(info->SCpnt);

                fas216_log(info, LOG_CONNECT, "data pointers: [%p, %X]",
                        info->scsi.SCp.ptr, info->scsi.SCp.this_residual);
                info->scsi.phase = PHASE_MSGIN;
        } else {
                /*
                 * Our command structure not found - abort the
                 * command on the target.  Since we have no
                 * record of this command, we can't send
                 * an INITIATOR DETECTED ERROR message.
                 */
                fas216_cmd(info, CMD_SETATN);

#if 0
                if (tag)
                        msgqueue_addmsg(&info->scsi.msgs, 2, ABORT_TAG, tag);
                else
#endif
                        msgqueue_addmsg(&info->scsi.msgs, 1, ABORT);
                info->scsi.phase = PHASE_MSGOUT_EXPECT;
                info->scsi.aborting = 1;
        }

        fas216_cmd(info, CMD_MSGACCEPTED);
        return;

 initiator_error:
        printk(KERN_ERR "scsi%d.H: error during reselection: bytes",
                info->host->host_no);
        for (i = 0; i < cfis; i++)
                printk(" %02x", msg[i]);
        printk("\n");
 bad_message:
        fas216_cmd(info, CMD_SETATN);
        msgqueue_flush(&info->scsi.msgs);
        msgqueue_addmsg(&info->scsi.msgs, 1, INITIATOR_ERROR);
        info->scsi.phase = PHASE_MSGOUT_EXPECT;
        fas216_cmd(info, CMD_MSGACCEPTED);
}

static void fas216_parse_message(FAS216_Info *info, unsigned char *message, int msglen)
{
        struct scsi_pointer *scsi_pointer;
        int i;

        switch (message[0]) {
        case COMMAND_COMPLETE:
                if (msglen != 1)
                        goto unrecognised;

                printk(KERN_ERR "scsi%d.%c: command complete with no "
                        "status in MESSAGE_IN?\n",
                        info->host->host_no, fas216_target(info));
                break;

        case SAVE_POINTERS:
                if (msglen != 1)
                        goto unrecognised;

                /*
                 * Save current data pointer to SAVED data pointer
                 * SCSI II standard says that we must not acknowledge
                 * this until we have really saved pointers.
                 * NOTE: we DO NOT save the command nor status pointers
                 * as required by the SCSI II standard.  These always
                 * point to the start of their respective areas.
                 */
                scsi_pointer = arm_scsi_pointer(info->SCpnt);
                *scsi_pointer = info->scsi.SCp;
                scsi_pointer->sent_command = 0;
                fas216_log(info, LOG_CONNECT | LOG_MESSAGES | LOG_BUFFER,
                        "save data pointers: [%p, %X]",
                        info->scsi.SCp.ptr, info->scsi.SCp.this_residual);
                break;

        case RESTORE_POINTERS:
                if (msglen != 1)
                        goto unrecognised;

                /*
                 * Restore current data pointer from SAVED data pointer
                 */
                info->scsi.SCp = *arm_scsi_pointer(info->SCpnt);
                fas216_log(info, LOG_CONNECT | LOG_MESSAGES | LOG_BUFFER,
                        "restore data pointers: [%p, 0x%x]",
                        info->scsi.SCp.ptr, info->scsi.SCp.this_residual);
                break;

        case DISCONNECT:
                if (msglen != 1)
                        goto unrecognised;

                info->scsi.phase = PHASE_MSGIN_DISCONNECT;
                break;

        case MESSAGE_REJECT:
                if (msglen != 1)
                        goto unrecognised;

                switch (fas216_get_last_msg(info, info->scsi.msgin_fifo)) {
                case EXTENDED_MESSAGE | EXTENDED_SDTR << 8:
                        fas216_handlesync(info, message);
                        break;

                default:
                        fas216_log(info, 0, "reject, last message 0x%04x",
                                fas216_get_last_msg(info, info->scsi.msgin_fifo));
                }
                break;

        case NOP:
                break;

        case EXTENDED_MESSAGE:
                if (msglen < 3)
                        goto unrecognised;

                switch (message[2]) {
                case EXTENDED_SDTR:     /* Sync transfer negotiation request/reply */
                        fas216_handlesync(info, message);
                        break;

                default:
                        goto unrecognised;
                }
                break;

        default:
                goto unrecognised;
        }
        return;

unrecognised:
        fas216_log(info, 0, "unrecognised message, rejecting");
        printk("scsi%d.%c: message was", info->host->host_no, fas216_target(info));
        for (i = 0; i < msglen; i++)
                printk("%s%02X", i & 31 ? " " : "\n  ", message[i]);
        printk("\n");

        /*
         * Something strange seems to be happening here -
         * I can't use SETATN since the chip gives me an
         * invalid command interrupt when I do.  Weird.
         */
fas216_cmd(info, CMD_NOP);
fas216_dumpstate(info);
        fas216_cmd(info, CMD_SETATN);
        msgqueue_flush(&info->scsi.msgs);
        msgqueue_addmsg(&info->scsi.msgs, 1, MESSAGE_REJECT);
        info->scsi.phase = PHASE_MSGOUT_EXPECT;
fas216_dumpstate(info);
}

static int fas216_wait_cmd(FAS216_Info *info, int cmd)
{
        int tout;
        int stat;

        fas216_cmd(info, cmd);

        for (tout = 1000; tout; tout -= 1) {
                stat = fas216_readb(info, REG_STAT);
                if (stat & (STAT_INT|STAT_PARITYERROR))
                        break;
                udelay(1);
        }

        return stat;
}

static int fas216_get_msg_byte(FAS216_Info *info)
{
        unsigned int stat = fas216_wait_cmd(info, CMD_MSGACCEPTED);

        if ((stat & STAT_INT) == 0)
                goto timedout;

        if ((stat & STAT_BUSMASK) != STAT_MESGIN)
                goto unexpected_phase_change;

        fas216_readb(info, REG_INST);

        stat = fas216_wait_cmd(info, CMD_TRANSFERINFO);

        if ((stat & STAT_INT) == 0)
                goto timedout;

        if (stat & STAT_PARITYERROR)
                goto parity_error;

        if ((stat & STAT_BUSMASK) != STAT_MESGIN)
                goto unexpected_phase_change;

        fas216_readb(info, REG_INST);

        return fas216_readb(info, REG_FF);

timedout:
        fas216_log(info, LOG_ERROR, "timed out waiting for message byte");
        return -1;

unexpected_phase_change:
        fas216_log(info, LOG_ERROR, "unexpected phase change: status = %02x", stat);
        return -2;

parity_error:
        fas216_log(info, LOG_ERROR, "parity error during message in phase");
        return -3;
}

/**
 * fas216_message - handle a function done interrupt from FAS216 chip
 * @info: interface which caused function done interrupt
 *
 * Handle a function done interrupt from FAS216 chip
 */
static void fas216_message(FAS216_Info *info)
{
        unsigned char *message = info->scsi.message;
        unsigned int msglen = 1;
        int msgbyte = 0;

        fas216_checkmagic(info);

        message[0] = fas216_readb(info, REG_FF);

        if (message[0] == EXTENDED_MESSAGE) {
                msgbyte = fas216_get_msg_byte(info);

                if (msgbyte >= 0) {
                        message[1] = msgbyte;

                        for (msglen = 2; msglen < message[1] + 2; msglen++) {
                                msgbyte = fas216_get_msg_byte(info);

                                if (msgbyte >= 0)
                                        message[msglen] = msgbyte;
                                else
                                        break;
                        }
                }
        }

        if (msgbyte == -3)
                goto parity_error;

#ifdef DEBUG_MESSAGES
        {
                int i;

                printk("scsi%d.%c: message in: ",
                        info->host->host_no, fas216_target(info));
                for (i = 0; i < msglen; i++)
                        printk("%02X ", message[i]);
                printk("\n");
        }
#endif

        fas216_parse_message(info, message, msglen);
        fas216_cmd(info, CMD_MSGACCEPTED);
        return;

parity_error:
        fas216_cmd(info, CMD_SETATN);
        msgqueue_flush(&info->scsi.msgs);
        msgqueue_addmsg(&info->scsi.msgs, 1, MSG_PARITY_ERROR);
        info->scsi.phase = PHASE_MSGOUT_EXPECT;
        fas216_cmd(info, CMD_MSGACCEPTED);
        return;
}

/**
 * fas216_send_command - send command after all message bytes have been sent
 * @info: interface which caused bus service
 *
 * Send a command to a target after all message bytes have been sent
 */
static void fas216_send_command(FAS216_Info *info)
{
        int i;

        fas216_checkmagic(info);

        fas216_cmd(info, CMD_NOP|CMD_WITHDMA);
        fas216_cmd(info, CMD_FLUSHFIFO);

        /* load command */
        for (i = info->scsi.SCp.sent_command; i < info->SCpnt->cmd_len; i++)
                fas216_writeb(info, REG_FF, info->SCpnt->cmnd[i]);

        fas216_cmd(info, CMD_TRANSFERINFO);

        info->scsi.phase = PHASE_COMMAND;
}

/**
 * fas216_send_messageout - handle bus service to send a message
 * @info: interface which caused bus service
 *
 * Handle bus service to send a message.
 * Note: We do not allow the device to change the data direction!
 */
static void fas216_send_messageout(FAS216_Info *info, int start)
{
        unsigned int tot_msglen = msgqueue_msglength(&info->scsi.msgs);

        fas216_checkmagic(info);

        fas216_cmd(info, CMD_FLUSHFIFO);

        if (tot_msglen) {
                struct message *msg;
                int msgnr = 0;

                while ((msg = msgqueue_getmsg(&info->scsi.msgs, msgnr++)) != NULL) {
                        int i;

                        for (i = start; i < msg->length; i++)
                                fas216_writeb(info, REG_FF, msg->msg[i]);

                        msg->fifo = tot_msglen - (fas216_readb(info, REG_CFIS) & CFIS_CF);
                        start = 0;
                }
        } else
                fas216_writeb(info, REG_FF, NOP);

        fas216_cmd(info, CMD_TRANSFERINFO);

        info->scsi.phase = PHASE_MSGOUT;
}

/**
 * fas216_busservice_intr - handle bus service interrupt from FAS216 chip
 * @info: interface which caused bus service interrupt
 * @stat: Status register contents
 * @is: SCSI Status register contents
 *
 * Handle a bus service interrupt from FAS216 chip
 */
static void fas216_busservice_intr(FAS216_Info *info, unsigned int stat, unsigned int is)
{
        fas216_checkmagic(info);

        fas216_log(info, LOG_BUSSERVICE,
                   "bus service: stat=%02x is=%02x phase=%02x",
                   stat, is, info->scsi.phase);

        switch (info->scsi.phase) {
        case PHASE_SELECTION:
                if ((is & IS_BITS) != IS_MSGBYTESENT)
                        goto bad_is;
                break;

        case PHASE_SELSTEPS:
                switch (is & IS_BITS) {
                case IS_SELARB:
                case IS_MSGBYTESENT:
                        goto bad_is;

                case IS_NOTCOMMAND:
                case IS_EARLYPHASE:
                        if ((stat & STAT_BUSMASK) == STAT_MESGIN)
                                break;
                        goto bad_is;

                case IS_COMPLETE:
                        break;
                }
                break;

        default:
                break;
        }

        fas216_cmd(info, CMD_NOP);

#define STATE(st,ph) ((ph) << 3 | (st))
        /* This table describes the legal SCSI state transitions,
         * as described by the SCSI II spec.
         */
        switch (STATE(stat & STAT_BUSMASK, info->scsi.phase)) {
        case STATE(STAT_DATAIN, PHASE_SELSTEPS):/* Sel w/ steps -> Data In      */
        case STATE(STAT_DATAIN, PHASE_MSGOUT):  /* Message Out  -> Data In      */
        case STATE(STAT_DATAIN, PHASE_COMMAND): /* Command      -> Data In      */
        case STATE(STAT_DATAIN, PHASE_MSGIN):   /* Message In   -> Data In      */
                info->scsi.phase = PHASE_DATAIN;
                fas216_transfer(info);
                return;

        case STATE(STAT_DATAIN, PHASE_DATAIN):  /* Data In      -> Data In      */
        case STATE(STAT_DATAOUT, PHASE_DATAOUT):/* Data Out     -> Data Out     */
                fas216_cleanuptransfer(info);
                fas216_transfer(info);
                return;

        case STATE(STAT_DATAOUT, PHASE_SELSTEPS):/* Sel w/ steps-> Data Out     */
        case STATE(STAT_DATAOUT, PHASE_MSGOUT): /* Message Out  -> Data Out     */
        case STATE(STAT_DATAOUT, PHASE_COMMAND):/* Command      -> Data Out     */
        case STATE(STAT_DATAOUT, PHASE_MSGIN):  /* Message In   -> Data Out     */
                fas216_cmd(info, CMD_FLUSHFIFO);
                info->scsi.phase = PHASE_DATAOUT;
                fas216_transfer(info);
                return;

        case STATE(STAT_STATUS, PHASE_DATAOUT): /* Data Out     -> Status       */
        case STATE(STAT_STATUS, PHASE_DATAIN):  /* Data In      -> Status       */
                fas216_stoptransfer(info);
                fallthrough;

        case STATE(STAT_STATUS, PHASE_SELSTEPS):/* Sel w/ steps -> Status       */
        case STATE(STAT_STATUS, PHASE_MSGOUT):  /* Message Out  -> Status       */
        case STATE(STAT_STATUS, PHASE_COMMAND): /* Command      -> Status       */
        case STATE(STAT_STATUS, PHASE_MSGIN):   /* Message In   -> Status       */
                fas216_cmd(info, CMD_INITCMDCOMPLETE);
                info->scsi.phase = PHASE_STATUS;
                return;

        case STATE(STAT_MESGIN, PHASE_DATAOUT): /* Data Out     -> Message In   */
        case STATE(STAT_MESGIN, PHASE_DATAIN):  /* Data In      -> Message In   */
                fas216_stoptransfer(info);
                fallthrough;

        case STATE(STAT_MESGIN, PHASE_COMMAND): /* Command      -> Message In   */
        case STATE(STAT_MESGIN, PHASE_SELSTEPS):/* Sel w/ steps -> Message In   */
        case STATE(STAT_MESGIN, PHASE_MSGOUT):  /* Message Out  -> Message In   */
                info->scsi.msgin_fifo = fas216_readb(info, REG_CFIS) & CFIS_CF;
                fas216_cmd(info, CMD_FLUSHFIFO);
                fas216_cmd(info, CMD_TRANSFERINFO);
                info->scsi.phase = PHASE_MSGIN;
                return;

        case STATE(STAT_MESGIN, PHASE_MSGIN):
                info->scsi.msgin_fifo = fas216_readb(info, REG_CFIS) & CFIS_CF;
                fas216_cmd(info, CMD_TRANSFERINFO);
                return;

        case STATE(STAT_COMMAND, PHASE_MSGOUT): /* Message Out  -> Command      */
        case STATE(STAT_COMMAND, PHASE_MSGIN):  /* Message In   -> Command      */
                fas216_send_command(info);
                info->scsi.phase = PHASE_COMMAND;
                return;


        /*
         * Selection    -> Message Out
         */
        case STATE(STAT_MESGOUT, PHASE_SELECTION):
                fas216_send_messageout(info, 1);
                return;

        /*
         * Message Out  -> Message Out
         */
        case STATE(STAT_MESGOUT, PHASE_SELSTEPS):
        case STATE(STAT_MESGOUT, PHASE_MSGOUT):
                /*
                 * If we get another message out phase, this usually
                 * means some parity error occurred.  Resend complete
                 * set of messages.  If we have more than one byte to
                 * send, we need to assert ATN again.
                 */
                if (info->device[info->SCpnt->device->id].parity_check) {
                        /*
                         * We were testing... good, the device
                         * supports parity checking.
                         */
                        info->device[info->SCpnt->device->id].parity_check = 0;
                        info->device[info->SCpnt->device->id].parity_enabled = 1;
                        fas216_writeb(info, REG_CNTL1, info->scsi.cfg[0]);
                }

                if (msgqueue_msglength(&info->scsi.msgs) > 1)
                        fas216_cmd(info, CMD_SETATN);
                fallthrough;

        /*
         * Any          -> Message Out
         */
        case STATE(STAT_MESGOUT, PHASE_MSGOUT_EXPECT):
                fas216_send_messageout(info, 0);
                return;

        /* Error recovery rules.
         *   These either attempt to abort or retry the operation.
         * TODO: we need more of these
         */
        case STATE(STAT_COMMAND, PHASE_COMMAND):/* Command      -> Command      */
                /* error - we've sent out all the command bytes
                 * we have.
                 * NOTE: we need SAVE DATA POINTERS/RESTORE DATA POINTERS
                 * to include the command bytes sent for this to work
                 * correctly.
                 */
                printk(KERN_ERR "scsi%d.%c: "
                        "target trying to receive more command bytes\n",
                        info->host->host_no, fas216_target(info));
                fas216_cmd(info, CMD_SETATN);
                fas216_set_stc(info, 15);
                fas216_cmd(info, CMD_PADBYTES | CMD_WITHDMA);
                msgqueue_flush(&info->scsi.msgs);
                msgqueue_addmsg(&info->scsi.msgs, 1, INITIATOR_ERROR);
                info->scsi.phase = PHASE_MSGOUT_EXPECT;
                return;
        }

        if (info->scsi.phase == PHASE_MSGIN_DISCONNECT) {
                printk(KERN_ERR "scsi%d.%c: disconnect message received, but bus service %s?\n",
                        info->host->host_no, fas216_target(info),
                        fas216_bus_phase(stat));
                msgqueue_flush(&info->scsi.msgs);
                fas216_cmd(info, CMD_SETATN);
                msgqueue_addmsg(&info->scsi.msgs, 1, INITIATOR_ERROR);
                info->scsi.phase = PHASE_MSGOUT_EXPECT;
                info->scsi.aborting = 1;
                fas216_cmd(info, CMD_TRANSFERINFO);
                return;
        }
        printk(KERN_ERR "scsi%d.%c: bus phase %s after %s?\n",
                info->host->host_no, fas216_target(info),
                fas216_bus_phase(stat),
                fas216_drv_phase(info));
        print_debug_list();
        return;

bad_is:
        fas216_log(info, 0, "bus service at step %d?", is & IS_BITS);
        fas216_dumpstate(info);
        print_debug_list();

        fas216_done(info, DID_ERROR);
}

/**
 * fas216_funcdone_intr - handle a function done interrupt from FAS216 chip
 * @info: interface which caused function done interrupt
 * @stat: Status register contents
 * @is: SCSI Status register contents
 *
 * Handle a function done interrupt from FAS216 chip
 */
static void fas216_funcdone_intr(FAS216_Info *info, unsigned int stat, unsigned int is)
{
        unsigned int fifo_len = fas216_readb(info, REG_CFIS) & CFIS_CF;

        fas216_checkmagic(info);

        fas216_log(info, LOG_FUNCTIONDONE,
                   "function done: stat=%02x is=%02x phase=%02x",
                   stat, is, info->scsi.phase);

        switch (info->scsi.phase) {
        case PHASE_STATUS:                      /* status phase - read status and msg   */
                if (fifo_len != 2) {
                        fas216_log(info, 0, "odd number of bytes in FIFO: %d", fifo_len);
                }
                /*
                 * Read status then message byte.
                 */
                info->scsi.SCp.Status = fas216_readb(info, REG_FF);
                info->scsi.SCp.Message = fas216_readb(info, REG_FF);
                info->scsi.phase = PHASE_DONE;
                fas216_cmd(info, CMD_MSGACCEPTED);
                break;

        case PHASE_IDLE:
        case PHASE_SELECTION:
        case PHASE_SELSTEPS:
                break;

        case PHASE_MSGIN:                       /* message in phase                     */
                if ((stat & STAT_BUSMASK) == STAT_MESGIN) {
                        info->scsi.msgin_fifo = fifo_len;
                        fas216_message(info);
                        break;
                }
                fallthrough;

        default:
                fas216_log(info, 0, "internal phase %s for function done?"
                        "  What do I do with this?",
                        fas216_target(info), fas216_drv_phase(info));
        }
}

static void fas216_bus_reset(FAS216_Info *info)
{
        neg_t sync_state;
        int i;

        msgqueue_flush(&info->scsi.msgs);

        sync_state = neg_invalid;

#ifdef SCSI2_SYNC
        if (info->ifcfg.capabilities & (FASCAP_DMA|FASCAP_PSEUDODMA))
                sync_state = neg_wait;
#endif

        info->scsi.phase = PHASE_IDLE;
        info->SCpnt = NULL; /* bug! */
        memset(&info->scsi.SCp, 0, sizeof(info->scsi.SCp));

        for (i = 0; i < 8; i++) {
                info->device[i].disconnect_ok   = info->ifcfg.disconnect_ok;
                info->device[i].sync_state      = sync_state;
                info->device[i].period          = info->ifcfg.asyncperiod / 4;
                info->device[i].stp             = info->scsi.async_stp;
                info->device[i].sof             = 0;
                info->device[i].wide_xfer       = 0;
        }

        info->rst_bus_status = 1;
        wake_up(&info->eh_wait);
}

/**
 * fas216_intr - handle interrupts to progress a command
 * @info: interface to service
 *
 * Handle interrupts from the interface to progress a command
 */
irqreturn_t fas216_intr(FAS216_Info *info)
{
        unsigned char inst, is, stat;
        int handled = IRQ_NONE;

        fas216_checkmagic(info);

        stat = fas216_readb(info, REG_STAT);
        is = fas216_readb(info, REG_IS);
        inst = fas216_readb(info, REG_INST);

        add_debug_list(stat, is, inst, info->scsi.phase);

        if (stat & STAT_INT) {
                if (inst & INST_BUSRESET) {
                        fas216_log(info, 0, "bus reset detected");
                        fas216_bus_reset(info);
                        scsi_report_bus_reset(info->host, 0);
                } else if (inst & INST_ILLEGALCMD) {
                        fas216_log(info, LOG_ERROR, "illegal command given\n");
                        fas216_dumpstate(info);
                        print_debug_list();
                } else if (inst & INST_DISCONNECT)
                        fas216_disconnect_intr(info);
                else if (inst & INST_RESELECTED)        /* reselected                   */
                        fas216_reselected_intr(info);
                else if (inst & INST_BUSSERVICE)        /* bus service request          */
                        fas216_busservice_intr(info, stat, is);
                else if (inst & INST_FUNCDONE)          /* function done                */
                        fas216_funcdone_intr(info, stat, is);
                else
                        fas216_log(info, 0, "unknown interrupt received:"
                                " phase %s inst %02X is %02X stat %02X",
                                fas216_drv_phase(info), inst, is, stat);
                handled = IRQ_HANDLED;
        }
        return handled;
}

static void __fas216_start_command(FAS216_Info *info, struct scsi_cmnd *SCpnt)
{
        int tot_msglen;

        /* following what the ESP driver says */
        fas216_set_stc(info, 0);
        fas216_cmd(info, CMD_NOP | CMD_WITHDMA);

        /* flush FIFO */
        fas216_cmd(info, CMD_FLUSHFIFO);

        /* load bus-id and timeout */
        fas216_writeb(info, REG_SDID, BUSID(SCpnt->device->id));
        fas216_writeb(info, REG_STIM, info->ifcfg.select_timeout);

        /* synchronous transfers */
        fas216_set_sync(info, SCpnt->device->id);

        tot_msglen = msgqueue_msglength(&info->scsi.msgs);

#ifdef DEBUG_MESSAGES
        {
                struct message *msg;
                int msgnr = 0, i;

                printk("scsi%d.%c: message out: ",
                        info->host->host_no, '0' + SCpnt->device->id);
                while ((msg = msgqueue_getmsg(&info->scsi.msgs, msgnr++)) != NULL) {
                        printk("{ ");
                        for (i = 0; i < msg->length; i++)
                                printk("%02x ", msg->msg[i]);
                        printk("} ");
                }
                printk("\n");
        }
#endif

        if (tot_msglen == 1 || tot_msglen == 3) {
                /*
                 * We have an easy message length to send...
                 */
                struct message *msg;
                int msgnr = 0, i;

                info->scsi.phase = PHASE_SELSTEPS;

                /* load message bytes */
                while ((msg = msgqueue_getmsg(&info->scsi.msgs, msgnr++)) != NULL) {
                        for (i = 0; i < msg->length; i++)
                                fas216_writeb(info, REG_FF, msg->msg[i]);
                        msg->fifo = tot_msglen - (fas216_readb(info, REG_CFIS) & CFIS_CF);
                }

                /* load command */
                for (i = 0; i < SCpnt->cmd_len; i++)
                        fas216_writeb(info, REG_FF, SCpnt->cmnd[i]);

                if (tot_msglen == 1)
                        fas216_cmd(info, CMD_SELECTATN);
                else
                        fas216_cmd(info, CMD_SELECTATN3);
        } else {
                /*
                 * We have an unusual number of message bytes to send.
                 *  Load first byte into fifo, and issue SELECT with ATN and
                 *  stop steps.
                 */
                struct message *msg = msgqueue_getmsg(&info->scsi.msgs, 0);

                fas216_writeb(info, REG_FF, msg->msg[0]);
                msg->fifo = 1;

                fas216_cmd(info, CMD_SELECTATNSTOP);
        }
}

/*
 * Decide whether we need to perform a parity test on this device.
 * Can also be used to force parity error conditions during initial
 * information transfer phase (message out) for test purposes.
 */
static int parity_test(FAS216_Info *info, int target)
{
#if 0
        if (target == 3) {
                info->device[target].parity_check = 0;
                return 1;
        }
#endif
        return info->device[target].parity_check;
}

static void fas216_start_command(FAS216_Info *info, struct scsi_cmnd *SCpnt)
{
        int disconnect_ok;

        /*
         * claim host busy
         */
        info->scsi.phase = PHASE_SELECTION;
        info->scsi.SCp = *arm_scsi_pointer(SCpnt);
        info->SCpnt = SCpnt;
        info->dma.transfer_type = fasdma_none;

        if (parity_test(info, SCpnt->device->id))
                fas216_writeb(info, REG_CNTL1, info->scsi.cfg[0] | CNTL1_PTE);
        else
                fas216_writeb(info, REG_CNTL1, info->scsi.cfg[0]);

        /*
         * Don't allow request sense commands to disconnect.
         */
        disconnect_ok = SCpnt->cmnd[0] != REQUEST_SENSE &&
                        info->device[SCpnt->device->id].disconnect_ok;

        /*
         * build outgoing message bytes
         */
        msgqueue_flush(&info->scsi.msgs);
        msgqueue_addmsg(&info->scsi.msgs, 1, IDENTIFY(disconnect_ok, SCpnt->device->lun));

        /*
         * add tag message if required
         */
        if (SCpnt->device->simple_tags)
                msgqueue_addmsg(&info->scsi.msgs, 2, SIMPLE_QUEUE_TAG,
                                scsi_cmd_to_rq(SCpnt)->tag);

        do {
#ifdef SCSI2_SYNC
                if ((info->device[SCpnt->device->id].sync_state == neg_wait ||
                     info->device[SCpnt->device->id].sync_state == neg_complete) &&
                    (SCpnt->cmnd[0] == REQUEST_SENSE ||
                     SCpnt->cmnd[0] == INQUIRY)) {
                        info->device[SCpnt->device->id].sync_state = neg_inprogress;
                        msgqueue_addmsg(&info->scsi.msgs, 5,
                                        EXTENDED_MESSAGE, 3, EXTENDED_SDTR,
                                        1000 / info->ifcfg.clockrate,
                                        info->ifcfg.sync_max_depth);
                        break;
                }
#endif
        } while (0);

        __fas216_start_command(info, SCpnt);
}

static void fas216_allocate_tag(FAS216_Info *info, struct scsi_cmnd *SCpnt)
{
        set_bit(SCpnt->device->id * 8 +
                (u8)(SCpnt->device->lun & 0x7), info->busyluns);

        info->stats.removes += 1;
        switch (SCpnt->cmnd[0]) {
        case WRITE_6:
        case WRITE_10:
        case WRITE_12:
                info->stats.writes += 1;
                break;
        case READ_6:
        case READ_10:
        case READ_12:
                info->stats.reads += 1;
                break;
        default:
                info->stats.miscs += 1;
                break;
        }
}

static void fas216_do_bus_device_reset(FAS216_Info *info,
                                       struct scsi_cmnd *SCpnt)
{
        struct message *msg;

        /*
         * claim host busy
         */
        info->scsi.phase = PHASE_SELECTION;
        info->scsi.SCp = *arm_scsi_pointer(SCpnt);
        info->SCpnt = SCpnt;
        info->dma.transfer_type = fasdma_none;

        fas216_log(info, LOG_ERROR, "sending bus device reset");

        msgqueue_flush(&info->scsi.msgs);
        msgqueue_addmsg(&info->scsi.msgs, 1, BUS_DEVICE_RESET);

        /* following what the ESP driver says */
        fas216_set_stc(info, 0);
        fas216_cmd(info, CMD_NOP | CMD_WITHDMA);

        /* flush FIFO */
        fas216_cmd(info, CMD_FLUSHFIFO);

        /* load bus-id and timeout */
        fas216_writeb(info, REG_SDID, BUSID(SCpnt->device->id));
        fas216_writeb(info, REG_STIM, info->ifcfg.select_timeout);

        /* synchronous transfers */
        fas216_set_sync(info, SCpnt->device->id);

        msg = msgqueue_getmsg(&info->scsi.msgs, 0);

        fas216_writeb(info, REG_FF, BUS_DEVICE_RESET);
        msg->fifo = 1;

        fas216_cmd(info, CMD_SELECTATNSTOP);
}

/**
 * fas216_kick - kick a command to the interface
 * @info: our host interface to kick
 *
 * Kick a command to the interface, interface should be idle.
 * Notes: Interrupts are always disabled!
 */
static void fas216_kick(FAS216_Info *info)
{
        struct scsi_cmnd *SCpnt = NULL;
#define TYPE_OTHER      0
#define TYPE_RESET      1
#define TYPE_QUEUE      2
        int where_from = TYPE_OTHER;

        fas216_checkmagic(info);

        /*
         * Obtain the next command to process.
         */
        do {
                if (info->rstSCpnt) {
                        SCpnt = info->rstSCpnt;
                        /* don't remove it */
                        where_from = TYPE_RESET;
                        break;
                }

                if (info->reqSCpnt) {
                        SCpnt = info->reqSCpnt;
                        info->reqSCpnt = NULL;
                        break;
                }

                if (info->origSCpnt) {
                        SCpnt = info->origSCpnt;
                        info->origSCpnt = NULL;
                        break;
                }

                /* retrieve next command */
                if (!SCpnt) {
                        SCpnt = queue_remove_exclude(&info->queues.issue,
                                                     info->busyluns);
                        where_from = TYPE_QUEUE;
                        break;
                }
        } while (0);

        if (!SCpnt) {
                /*
                 * no command pending, so enable reselection.
                 */
                fas216_cmd(info, CMD_ENABLESEL);
                return;
        }

        /*
         * We're going to start a command, so disable reselection
         */
        fas216_cmd(info, CMD_DISABLESEL);

        if (info->scsi.disconnectable && info->SCpnt) {
                fas216_log(info, LOG_CONNECT,
                        "moved command for %d to disconnected queue",
                        info->SCpnt->device->id);
                queue_add_cmd_tail(&info->queues.disconnected, info->SCpnt);
                info->scsi.disconnectable = 0;
                info->SCpnt = NULL;
        }

        fas216_log_command(info, LOG_CONNECT | LOG_MESSAGES, SCpnt,
                           "starting");

        switch (where_from) {
        case TYPE_QUEUE:
                fas216_allocate_tag(info, SCpnt);
                fallthrough;
        case TYPE_OTHER:
                fas216_start_command(info, SCpnt);
                break;
        case TYPE_RESET:
                fas216_do_bus_device_reset(info, SCpnt);
                break;
        }

        fas216_log(info, LOG_CONNECT, "select: data pointers [%p, %X]",
                info->scsi.SCp.ptr, info->scsi.SCp.this_residual);

        /*
         * should now get either DISCONNECT or
         * (FUNCTION DONE with BUS SERVICE) interrupt
         */
}

/*
 * Clean up from issuing a BUS DEVICE RESET message to a device.
 */
static void fas216_devicereset_done(FAS216_Info *info, struct scsi_cmnd *SCpnt,
                                    unsigned int result)
{
        fas216_log(info, LOG_ERROR, "fas216 device reset complete");

        info->rstSCpnt = NULL;
        info->rst_dev_status = 1;
        wake_up(&info->eh_wait);
}

/**
 * fas216_rq_sns_done - Finish processing automatic request sense command
 * @info: interface that completed
 * @SCpnt: command that completed
 * @result: driver byte of result
 *
 * Finish processing automatic request sense command
 */
static void fas216_rq_sns_done(FAS216_Info *info, struct scsi_cmnd *SCpnt,
                               unsigned int result)
{
        struct scsi_pointer *scsi_pointer = arm_scsi_pointer(SCpnt);

        fas216_log_target(info, LOG_CONNECT, SCpnt->device->id,
                   "request sense complete, result=0x%04x%02x%02x",
                   result, scsi_pointer->Message, scsi_pointer->Status);

        if (result != DID_OK || scsi_pointer->Status != SAM_STAT_GOOD)
                /*
                 * Something went wrong.  Make sure that we don't
                 * have valid data in the sense buffer that could
                 * confuse the higher levels.
                 */
                memset(SCpnt->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
//printk("scsi%d.%c: sense buffer: ", info->host->host_no, '0' + SCpnt->device->id);
//{ int i; for (i = 0; i < 32; i++) printk("%02x ", SCpnt->sense_buffer[i]); printk("\n"); }
        /*
         * Note that we don't set SCpnt->result, since that should
         * reflect the status of the command that we were asked by
         * the upper layers to process.  This would have been set
         * correctly by fas216_std_done.
         */
        scsi_eh_restore_cmnd(SCpnt, &info->ses);
        fas216_cmd_priv(SCpnt)->scsi_done(SCpnt);
}

/**
 * fas216_std_done - finish processing of standard command
 * @info: interface that completed
 * @SCpnt: command that completed
 * @result: driver byte of result
 *
 * Finish processing of standard command
 */
static void
fas216_std_done(FAS216_Info *info, struct scsi_cmnd *SCpnt, unsigned int result)
{
        struct scsi_pointer *scsi_pointer = arm_scsi_pointer(SCpnt);

        info->stats.fins += 1;

        set_host_byte(SCpnt, result);
        if (result == DID_OK)
                scsi_msg_to_host_byte(SCpnt, info->scsi.SCp.Message);
        set_status_byte(SCpnt, info->scsi.SCp.Status);

        fas216_log_command(info, LOG_CONNECT, SCpnt,
                "command complete, result=0x%08x", SCpnt->result);

        /*
         * If the driver detected an error, we're all done.
         */
        if (get_host_byte(SCpnt) != DID_OK)
                goto done;

        /*
         * If the command returned CHECK_CONDITION or COMMAND_TERMINATED
         * status, request the sense information.
         */
        if (get_status_byte(SCpnt) == SAM_STAT_CHECK_CONDITION ||
            get_status_byte(SCpnt) == SAM_STAT_COMMAND_TERMINATED)
                goto request_sense;

        /*
         * If the command did not complete with GOOD status,
         * we are all done here.
         */
        if (get_status_byte(SCpnt) != SAM_STAT_GOOD)
                goto done;

        /*
         * We have successfully completed a command.  Make sure that
         * we do not have any buffers left to transfer.  The world
         * is not perfect, and we seem to occasionally hit this.
         * It can be indicative of a buggy driver, target or the upper
         * levels of the SCSI code.
         */
        if (info->scsi.SCp.ptr) {
                switch (SCpnt->cmnd[0]) {
                case INQUIRY:
                case START_STOP:
                case MODE_SENSE:
                        break;

                default:
                        scmd_printk(KERN_ERR, SCpnt,
                                    "incomplete data transfer detected: res=%08X ptr=%p len=%X\n",
                                    SCpnt->result, info->scsi.SCp.ptr,
                                    info->scsi.SCp.this_residual);
                        scsi_print_command(SCpnt);
                        set_host_byte(SCpnt, DID_ERROR);
                        goto request_sense;
                }
        }

done:
        if (fas216_cmd_priv(SCpnt)->scsi_done) {
                fas216_cmd_priv(SCpnt)->scsi_done(SCpnt);
                return;
        }

        panic("scsi%d.H: null scsi_done function in fas216_done",
                info->host->host_no);


request_sense:
        if (SCpnt->cmnd[0] == REQUEST_SENSE)
                goto done;

        scsi_eh_prep_cmnd(SCpnt, &info->ses, NULL, 0, ~0);
        fas216_log_target(info, LOG_CONNECT, SCpnt->device->id,
                          "requesting sense");
        init_SCp(SCpnt);
        scsi_pointer->Message = 0;
        scsi_pointer->Status = 0;
        SCpnt->host_scribble = (void *)fas216_rq_sns_done;

        /*
         * Place this command into the high priority "request
         * sense" slot.  This will be the very next command
         * executed, unless a target connects to us.
         */
        if (info->reqSCpnt)
                printk(KERN_WARNING "scsi%d.%c: losing request command\n",
                        info->host->host_no, '0' + SCpnt->device->id);
        info->reqSCpnt = SCpnt;
}

/**
 * fas216_done - complete processing for current command
 * @info: interface that completed
 * @result: driver byte of result
 *
 * Complete processing for current command
 */
static void fas216_done(FAS216_Info *info, unsigned int result)
{
        void (*fn)(FAS216_Info *, struct scsi_cmnd *, unsigned int);
        struct scsi_cmnd *SCpnt;
        unsigned long flags;

        fas216_checkmagic(info);

        if (!info->SCpnt)
                goto no_command;

        SCpnt = info->SCpnt;
        info->SCpnt = NULL;
        info->scsi.phase = PHASE_IDLE;

        if (info->scsi.aborting) {
                fas216_log(info, 0, "uncaught abort - returning DID_ABORT");
                result = DID_ABORT;
                info->scsi.aborting = 0;
        }

        /*
         * Sanity check the completion - if we have zero bytes left
         * to transfer, we should not have a valid pointer.
         */
        if (info->scsi.SCp.ptr && info->scsi.SCp.this_residual == 0) {
                scmd_printk(KERN_INFO, SCpnt,
                            "zero bytes left to transfer, but buffer pointer still valid: ptr=%p len=%08x\n",
                            info->scsi.SCp.ptr, info->scsi.SCp.this_residual);
                info->scsi.SCp.ptr = NULL;
                scsi_print_command(SCpnt);
        }

        /*
         * Clear down this command as completed.  If we need to request
         * the sense information, fas216_kick will re-assert the busy
         * status.
         */
        info->device[SCpnt->device->id].parity_check = 0;
        clear_bit(SCpnt->device->id * 8 +
                  (u8)(SCpnt->device->lun & 0x7), info->busyluns);

        fn = (void (*)(FAS216_Info *, struct scsi_cmnd *, unsigned int))SCpnt->host_scribble;
        fn(info, SCpnt, result);

        if (info->scsi.irq) {
                spin_lock_irqsave(&info->host_lock, flags);
                if (info->scsi.phase == PHASE_IDLE)
                        fas216_kick(info);
                spin_unlock_irqrestore(&info->host_lock, flags);
        }
        return;

no_command:
        panic("scsi%d.H: null command in fas216_done",
                info->host->host_no);
}

/**
 * fas216_queue_command_internal - queue a command for the adapter to process
 * @SCpnt: Command to queue
 * @done: done function to call once command is complete
 *
 * Queue a command for adapter to process.
 * Returns: 0 on success, else error.
 * Notes: io_request_lock is held, interrupts are disabled.
 */
static enum scsi_qc_status
fas216_queue_command_internal(struct scsi_cmnd *SCpnt,
                              void (*done)(struct scsi_cmnd *))
{
        FAS216_Info *info = (FAS216_Info *)SCpnt->device->host->hostdata;
        enum scsi_qc_status result;

        fas216_checkmagic(info);

        fas216_log_command(info, LOG_CONNECT, SCpnt,
                           "received command (%p)", SCpnt);

        fas216_cmd_priv(SCpnt)->scsi_done = done;
        SCpnt->host_scribble = (void *)fas216_std_done;
        SCpnt->result = 0;

        init_SCp(SCpnt);

        info->stats.queues += 1;

        spin_lock(&info->host_lock);

        /*
         * Add command into execute queue and let it complete under
         * whatever scheme we're using.
         */
        result = !queue_add_cmd_ordered(&info->queues.issue, SCpnt);

        /*
         * If we successfully added the command,
         * kick the interface to get it moving.
         */
        if (result == 0 && info->scsi.phase == PHASE_IDLE)
                fas216_kick(info);
        spin_unlock(&info->host_lock);

        fas216_log_target(info, LOG_CONNECT, -1, "queue %s",
                result ? "failure" : "success");

        return result;
}

static enum scsi_qc_status fas216_queue_command_lck(struct scsi_cmnd *SCpnt)
{
        return fas216_queue_command_internal(SCpnt, scsi_done);
}

DEF_SCSI_QCMD(fas216_queue_command)

/**
 * fas216_internal_done - trigger restart of a waiting thread in fas216_noqueue_command
 * @SCpnt: Command to wake
 *
 * Trigger restart of a waiting thread in fas216_command
 */
static void fas216_internal_done(struct scsi_cmnd *SCpnt)
{
        FAS216_Info *info = (FAS216_Info *)SCpnt->device->host->hostdata;

        fas216_checkmagic(info);

        info->internal_done = 1;
}

/**
 * fas216_noqueue_command - process a command for the adapter.
 * @SCpnt: Command to queue
 *
 * Queue a command for adapter to process.
 * Returns: scsi result code.
 * Notes: io_request_lock is held, interrupts are disabled.
 */
static enum scsi_qc_status fas216_noqueue_command_lck(struct scsi_cmnd *SCpnt)
{
        FAS216_Info *info = (FAS216_Info *)SCpnt->device->host->hostdata;

        fas216_checkmagic(info);

        /*
         * We should only be using this if we don't have an interrupt.
         * Provide some "incentive" to use the queueing code.
         */
        BUG_ON(info->scsi.irq);

        info->internal_done = 0;
        fas216_queue_command_internal(SCpnt, fas216_internal_done);

        /*
         * This wastes time, since we can't return until the command is
         * complete. We can't sleep either since we may get re-entered!
         * However, we must re-enable interrupts, or else we'll be
         * waiting forever.
         */
        spin_unlock_irq(info->host->host_lock);

        while (!info->internal_done) {
                /*
                 * If we don't have an IRQ, then we must poll the card for
                 * it's interrupt, and use that to call this driver's
                 * interrupt routine.  That way, we keep the command
                 * progressing.  Maybe we can add some intelligence here
                 * and go to sleep if we know that the device is going
                 * to be some time (eg, disconnected).
                 */
                if (fas216_readb(info, REG_STAT) & STAT_INT) {
                        spin_lock_irq(info->host->host_lock);
                        fas216_intr(info);
                        spin_unlock_irq(info->host->host_lock);
                }
        }

        spin_lock_irq(info->host->host_lock);

        scsi_done(SCpnt);

        return 0;
}

DEF_SCSI_QCMD(fas216_noqueue_command)

/*
 * Error handler timeout function.  Indicate that we timed out,
 * and wake up any error handler process so it can continue.
 */
static void fas216_eh_timer(struct timer_list *t)
{
        FAS216_Info *info = timer_container_of(info, t, eh_timer);

        fas216_log(info, LOG_ERROR, "error handling timed out\n");

        timer_delete(&info->eh_timer);

        if (info->rst_bus_status == 0)
                info->rst_bus_status = -1;
        if (info->rst_dev_status == 0)
                info->rst_dev_status = -1;

        wake_up(&info->eh_wait);
}

enum res_find {
        res_failed,             /* not found                    */
        res_success,            /* command on issue queue       */
        res_hw_abort            /* command on disconnected dev  */
};

/**
 * fas216_do_abort - decide how to abort a command
 * @SCpnt: command to abort
 *
 * Decide how to abort a command.
 * Returns: abort status
 */
static enum res_find fas216_find_command(FAS216_Info *info,
                                         struct scsi_cmnd *SCpnt)
{
        enum res_find res = res_failed;

        if (queue_remove_cmd(&info->queues.issue, SCpnt)) {
                /*
                 * The command was on the issue queue, and has not been
                 * issued yet.  We can remove the command from the queue,
                 * and acknowledge the abort.  Neither the device nor the
                 * interface know about the command.
                 */
                printk("on issue queue ");

                res = res_success;
        } else if (queue_remove_cmd(&info->queues.disconnected, SCpnt)) {
                /*
                 * The command was on the disconnected queue.  We must
                 * reconnect with the device if possible, and send it
                 * an abort message.
                 */
                printk("on disconnected queue ");

                res = res_hw_abort;
        } else if (info->SCpnt == SCpnt) {
                printk("executing ");

                switch (info->scsi.phase) {
                /*
                 * If the interface is idle, and the command is 'disconnectable',
                 * then it is the same as on the disconnected queue.
                 */
                case PHASE_IDLE:
                        if (info->scsi.disconnectable) {
                                info->scsi.disconnectable = 0;
                                info->SCpnt = NULL;
                                res = res_hw_abort;
                        }
                        break;

                default:
                        break;
                }
        } else if (info->origSCpnt == SCpnt) {
                /*
                 * The command will be executed next, but a command
                 * is currently using the interface.  This is similar to
                 * being on the issue queue, except the busylun bit has
                 * been set.
                 */
                info->origSCpnt = NULL;
                clear_bit(SCpnt->device->id * 8 +
                          (u8)(SCpnt->device->lun & 0x7), info->busyluns);
                printk("waiting for execution ");
                res = res_success;
        } else
                printk("unknown ");

        return res;
}

/**
 * fas216_eh_abort - abort this command
 * @SCpnt: command to abort
 *
 * Abort this command.
 * Returns: FAILED if unable to abort
 * Notes: io_request_lock is taken, and irqs are disabled
 */
int fas216_eh_abort(struct scsi_cmnd *SCpnt)
{
        FAS216_Info *info = (FAS216_Info *)SCpnt->device->host->hostdata;
        int result = FAILED;

        fas216_checkmagic(info);

        info->stats.aborts += 1;

        scmd_printk(KERN_WARNING, SCpnt, "abort command\n");

        print_debug_list();
        fas216_dumpstate(info);

        switch (fas216_find_command(info, SCpnt)) {
        /*
         * We found the command, and cleared it out.  Either
         * the command is still known to be executing on the
         * target, or the busylun bit is not set.
         */
        case res_success:
                scmd_printk(KERN_WARNING, SCpnt, "abort %p success\n", SCpnt);
                result = SUCCESS;
                break;

        /*
         * We need to reconnect to the target and send it an
         * ABORT or ABORT_TAG message.  We can only do this
         * if the bus is free.
         */
        case res_hw_abort:

        /*
         * We are unable to abort the command for some reason.
         */
        default:
        case res_failed:
                scmd_printk(KERN_WARNING, SCpnt, "abort %p failed\n", SCpnt);
                break;
        }

        return result;
}

/**
 * fas216_eh_device_reset - Reset the device associated with this command
 * @SCpnt: command specifing device to reset
 *
 * Reset the device associated with this command.
 * Returns: FAILED if unable to reset.
 * Notes: We won't be re-entered, so we'll only have one device
 * reset on the go at one time.
 */
int fas216_eh_device_reset(struct scsi_cmnd *SCpnt)
{
        FAS216_Info *info = (FAS216_Info *)SCpnt->device->host->hostdata;
        unsigned long flags;
        int i, res = FAILED, target = SCpnt->device->id;

        fas216_log(info, LOG_ERROR, "device reset for target %d", target);

        spin_lock_irqsave(&info->host_lock, flags);

        do {
                /*
                 * If we are currently connected to a device, and
                 * it is the device we want to reset, there is
                 * nothing we can do here.  Chances are it is stuck,
                 * and we need a bus reset.
                 */
                if (info->SCpnt && !info->scsi.disconnectable &&
                    info->SCpnt->device->id == SCpnt->device->id)
                        break;

                /*
                 * We're going to be resetting this device.  Remove
                 * all pending commands from the driver.  By doing
                 * so, we guarantee that we won't touch the command
                 * structures except to process the reset request.
                 */
                queue_remove_all_target(&info->queues.issue, target);
                queue_remove_all_target(&info->queues.disconnected, target);
                if (info->origSCpnt && info->origSCpnt->device->id == target)
                        info->origSCpnt = NULL;
                if (info->reqSCpnt && info->reqSCpnt->device->id == target)
                        info->reqSCpnt = NULL;
                for (i = 0; i < 8; i++)
                        clear_bit(target * 8 + i, info->busyluns);

                /*
                 * Hijack this SCSI command structure to send
                 * a bus device reset message to this device.
                 */
                SCpnt->host_scribble = (void *)fas216_devicereset_done;

                info->rst_dev_status = 0;
                info->rstSCpnt = SCpnt;

                if (info->scsi.phase == PHASE_IDLE)
                        fas216_kick(info);

                mod_timer(&info->eh_timer, jiffies + 30 * HZ);
                spin_unlock_irqrestore(&info->host_lock, flags);

                /*
                 * Wait up to 30 seconds for the reset to complete.
                 */
                wait_event(info->eh_wait, info->rst_dev_status);

                timer_delete_sync(&info->eh_timer);
                spin_lock_irqsave(&info->host_lock, flags);
                info->rstSCpnt = NULL;

                if (info->rst_dev_status == 1)
                        res = SUCCESS;
        } while (0);

        SCpnt->host_scribble = NULL;
        spin_unlock_irqrestore(&info->host_lock, flags);

        fas216_log(info, LOG_ERROR, "device reset complete: %s\n",
                   res == SUCCESS ? "success" : "failed");

        return res;
}

/**
 * fas216_eh_bus_reset - Reset the bus associated with the command
 * @SCpnt: command specifing bus to reset
 *
 * Reset the bus associated with the command.
 * Returns: FAILED if unable to reset.
 * Notes: Further commands are blocked.
 */
int fas216_eh_bus_reset(struct scsi_cmnd *SCpnt)
{
        FAS216_Info *info = (FAS216_Info *)SCpnt->device->host->hostdata;
        unsigned long flags;
        struct scsi_device *SDpnt;

        fas216_checkmagic(info);
        fas216_log(info, LOG_ERROR, "resetting bus");

        info->stats.bus_resets += 1;

        spin_lock_irqsave(&info->host_lock, flags);

        /*
         * Stop all activity on this interface.
         */
        fas216_aborttransfer(info);
        fas216_writeb(info, REG_CNTL3, info->scsi.cfg[2]);

        /*
         * Clear any pending interrupts.
         */
        while (fas216_readb(info, REG_STAT) & STAT_INT)
                fas216_readb(info, REG_INST);

        info->rst_bus_status = 0;

        /*
         * For each attached hard-reset device, clear out
         * all command structures.  Leave the running
         * command in place.
         */
        shost_for_each_device(SDpnt, info->host) {
                int i;

                if (SDpnt->soft_reset)
                        continue;

                queue_remove_all_target(&info->queues.issue, SDpnt->id);
                queue_remove_all_target(&info->queues.disconnected, SDpnt->id);
                if (info->origSCpnt && info->origSCpnt->device->id == SDpnt->id)
                        info->origSCpnt = NULL;
                if (info->reqSCpnt && info->reqSCpnt->device->id == SDpnt->id)
                        info->reqSCpnt = NULL;
                info->SCpnt = NULL;

                for (i = 0; i < 8; i++)
                        clear_bit(SDpnt->id * 8 + i, info->busyluns);
        }

        info->scsi.phase = PHASE_IDLE;

        /*
         * Reset the SCSI bus.  Device cleanup happens in
         * the interrupt handler.
         */
        fas216_cmd(info, CMD_RESETSCSI);

        mod_timer(&info->eh_timer, jiffies + HZ);
        spin_unlock_irqrestore(&info->host_lock, flags);

        /*
         * Wait one second for the interrupt.
         */
        wait_event(info->eh_wait, info->rst_bus_status);
        timer_delete_sync(&info->eh_timer);

        fas216_log(info, LOG_ERROR, "bus reset complete: %s\n",
                   info->rst_bus_status == 1 ? "success" : "failed");

        return info->rst_bus_status == 1 ? SUCCESS : FAILED;
}

/**
 * fas216_init_chip - Initialise FAS216 state after reset
 * @info: state structure for interface
 *
 * Initialise FAS216 state after reset
 */
static void fas216_init_chip(FAS216_Info *info)
{
        unsigned int clock = ((info->ifcfg.clockrate - 1) / 5 + 1) & 7;
        fas216_writeb(info, REG_CLKF, clock);
        fas216_writeb(info, REG_CNTL1, info->scsi.cfg[0]);
        fas216_writeb(info, REG_CNTL2, info->scsi.cfg[1]);
        fas216_writeb(info, REG_CNTL3, info->scsi.cfg[2]);
        fas216_writeb(info, REG_STIM, info->ifcfg.select_timeout);
        fas216_writeb(info, REG_SOF, 0);
        fas216_writeb(info, REG_STP, info->scsi.async_stp);
        fas216_writeb(info, REG_CNTL1, info->scsi.cfg[0]);
}

/**
 * fas216_eh_host_reset - Reset the host associated with this command
 * @SCpnt: command specifing host to reset
 *
 * Reset the host associated with this command.
 * Returns: FAILED if unable to reset.
 * Notes: io_request_lock is taken, and irqs are disabled
 */
int fas216_eh_host_reset(struct scsi_cmnd *SCpnt)
{
        FAS216_Info *info = (FAS216_Info *)SCpnt->device->host->hostdata;

        spin_lock_irq(info->host->host_lock);

        fas216_checkmagic(info);

        fas216_log(info, LOG_ERROR, "resetting host");

        /*
         * Reset the SCSI chip.
         */
        fas216_cmd(info, CMD_RESETCHIP);

        /*
         * Ugly ugly ugly!
         * We need to release the host_lock and enable
         * IRQs if we sleep, but we must relock and disable
         * IRQs after the sleep.
         */
        spin_unlock_irq(info->host->host_lock);
        msleep(50 * 1000/100);
        spin_lock_irq(info->host->host_lock);

        /*
         * Release the SCSI reset.
         */
        fas216_cmd(info, CMD_NOP);

        fas216_init_chip(info);

        spin_unlock_irq(info->host->host_lock);
        return SUCCESS;
}

#define TYPE_UNKNOWN    0
#define TYPE_NCR53C90   1
#define TYPE_NCR53C90A  2
#define TYPE_NCR53C9x   3
#define TYPE_Am53CF94   4
#define TYPE_EmFAS216   5
#define TYPE_QLFAS216   6

static char *chip_types[] = {
        "unknown",
        "NS NCR53C90",
        "NS NCR53C90A",
        "NS NCR53C9x",
        "AMD Am53CF94",
        "Emulex FAS216",
        "QLogic FAS216"
};

static int fas216_detect_type(FAS216_Info *info)
{
        int family, rev;

        /*
         * Reset the chip.
         */
        fas216_writeb(info, REG_CMD, CMD_RESETCHIP);
        udelay(50);
        fas216_writeb(info, REG_CMD, CMD_NOP);

        /*
         * Check to see if control reg 2 is present.
         */
        fas216_writeb(info, REG_CNTL3, 0);
        fas216_writeb(info, REG_CNTL2, CNTL2_S2FE);

        /*
         * If we are unable to read back control reg 2
         * correctly, it is not present, and we have a
         * NCR53C90.
         */
        if ((fas216_readb(info, REG_CNTL2) & (~0xe0)) != CNTL2_S2FE)
                return TYPE_NCR53C90;

        /*
         * Now, check control register 3
         */
        fas216_writeb(info, REG_CNTL2, 0);
        fas216_writeb(info, REG_CNTL3, 0);
        fas216_writeb(info, REG_CNTL3, 5);

        /*
         * If we are unable to read the register back
         * correctly, we have a NCR53C90A
         */
        if (fas216_readb(info, REG_CNTL3) != 5)
                return TYPE_NCR53C90A;

        /*
         * Now read the ID from the chip.
         */
        fas216_writeb(info, REG_CNTL3, 0);

        fas216_writeb(info, REG_CNTL3, CNTL3_ADIDCHK);
        fas216_writeb(info, REG_CNTL3, 0);

        fas216_writeb(info, REG_CMD, CMD_RESETCHIP);
        udelay(50);
        fas216_writeb(info, REG_CMD, CMD_WITHDMA | CMD_NOP);

        fas216_writeb(info, REG_CNTL2, CNTL2_ENF);
        fas216_writeb(info, REG_CMD, CMD_RESETCHIP);
        udelay(50);
        fas216_writeb(info, REG_CMD, CMD_NOP);

        rev     = fas216_readb(info, REG_ID);
        family  = rev >> 3;
        rev    &= 7;

        switch (family) {
        case 0x01:
                if (rev == 4)
                        return TYPE_Am53CF94;
                break;

        case 0x02:
                switch (rev) {
                case 2:
                        return TYPE_EmFAS216;
                case 3:
                        return TYPE_QLFAS216;
                }
                break;

        default:
                break;
        }
        printk("family %x rev %x\n", family, rev);
        return TYPE_NCR53C9x;
}

/**
 * fas216_reset_state - Initialise driver internal state
 * @info: state to initialise
 *
 * Initialise driver internal state
 */
static void fas216_reset_state(FAS216_Info *info)
{
        int i;

        fas216_checkmagic(info);

        fas216_bus_reset(info);

        /*
         * Clear out all stale info in our state structure
         */
        memset(info->busyluns, 0, sizeof(info->busyluns));
        info->scsi.disconnectable = 0;
        info->scsi.aborting = 0;

        for (i = 0; i < 8; i++) {
                info->device[i].parity_enabled  = 0;
                info->device[i].parity_check    = 1;
        }

        /*
         * Drain all commands on disconnected queue
         */
        while (queue_remove(&info->queues.disconnected) != NULL);

        /*
         * Remove executing commands.
         */
        info->SCpnt     = NULL;
        info->reqSCpnt  = NULL;
        info->rstSCpnt  = NULL;
        info->origSCpnt = NULL;
}

/**
 * fas216_init - initialise FAS/NCR/AMD SCSI structures.
 * @host: a driver-specific filled-out structure
 *
 * Initialise FAS/NCR/AMD SCSI structures.
 * Returns: 0 on success
 */
int fas216_init(struct Scsi_Host *host)
{
        FAS216_Info *info = (FAS216_Info *)host->hostdata;

        info->magic_start    = MAGIC;
        info->magic_end      = MAGIC;
        info->host           = host;
        info->scsi.cfg[0]    = host->this_id | CNTL1_PERE;
        info->scsi.cfg[1]    = CNTL2_ENF | CNTL2_S2FE;
        info->scsi.cfg[2]    = info->ifcfg.cntl3 |
                               CNTL3_ADIDCHK | CNTL3_QTAG | CNTL3_G2CB | CNTL3_LBTM;
        info->scsi.async_stp = fas216_syncperiod(info, info->ifcfg.asyncperiod);

        info->rst_dev_status = -1;
        info->rst_bus_status = -1;
        init_waitqueue_head(&info->eh_wait);
        timer_setup(&info->eh_timer, fas216_eh_timer, 0);
        
        spin_lock_init(&info->host_lock);

        memset(&info->stats, 0, sizeof(info->stats));

        msgqueue_initialise(&info->scsi.msgs);

        if (!queue_initialise(&info->queues.issue))
                return -ENOMEM;

        if (!queue_initialise(&info->queues.disconnected)) {
                queue_free(&info->queues.issue);
                return -ENOMEM;
        }

        return 0;
}

/**
 * fas216_add - initialise FAS/NCR/AMD SCSI ic.
 * @host: a driver-specific filled-out structure
 * @dev: parent device
 *
 * Initialise FAS/NCR/AMD SCSI ic.
 * Returns: 0 on success
 */
int fas216_add(struct Scsi_Host *host, struct device *dev)
{
        FAS216_Info *info = (FAS216_Info *)host->hostdata;
        int type, ret;

        if (info->ifcfg.clockrate <= 10 || info->ifcfg.clockrate > 40) {
                printk(KERN_CRIT "fas216: invalid clock rate %u MHz\n",
                        info->ifcfg.clockrate);
                return -EINVAL;
        }

        fas216_reset_state(info);
        type = fas216_detect_type(info);
        info->scsi.type = chip_types[type];

        udelay(300);

        /*
         * Initialise the chip correctly.
         */
        fas216_init_chip(info);

        /*
         * Reset the SCSI bus.  We don't want to see
         * the resulting reset interrupt, so mask it
         * out.
         */
        fas216_writeb(info, REG_CNTL1, info->scsi.cfg[0] | CNTL1_DISR);
        fas216_writeb(info, REG_CMD, CMD_RESETSCSI);

        /*
         * scsi standard says wait 250ms
         */
        spin_unlock_irq(info->host->host_lock);
        msleep(100*1000/100);
        spin_lock_irq(info->host->host_lock);

        fas216_writeb(info, REG_CNTL1, info->scsi.cfg[0]);
        fas216_readb(info, REG_INST);

        fas216_checkmagic(info);

        ret = scsi_add_host(host, dev);
        if (ret)
                fas216_writeb(info, REG_CMD, CMD_RESETCHIP);
        else
                scsi_scan_host(host);

        return ret;
}

void fas216_remove(struct Scsi_Host *host)
{
        FAS216_Info *info = (FAS216_Info *)host->hostdata;

        fas216_checkmagic(info);
        scsi_remove_host(host);

        fas216_writeb(info, REG_CMD, CMD_RESETCHIP);
        scsi_host_put(host);
}

/**
 * fas216_release - release all resources for FAS/NCR/AMD SCSI ic.
 * @host: a driver-specific filled-out structure
 *
 * release all resources and put everything to bed for FAS/NCR/AMD SCSI ic.
 */
void fas216_release(struct Scsi_Host *host)
{
        FAS216_Info *info = (FAS216_Info *)host->hostdata;

        queue_free(&info->queues.disconnected);
        queue_free(&info->queues.issue);
}

void fas216_print_host(FAS216_Info *info, struct seq_file *m)
{
        seq_printf(m,
                        "\n"
                        "Chip    : %s\n"
                        " Address: 0x%p\n"
                        " IRQ    : %d\n"
                        " DMA    : %d\n",
                        info->scsi.type, info->scsi.io_base,
                        info->scsi.irq, info->scsi.dma);
}

void fas216_print_stats(FAS216_Info *info, struct seq_file *m)
{
        seq_printf(m, "\n"
                        "Command Statistics:\n"
                        " Queued     : %u\n"
                        " Issued     : %u\n"
                        " Completed  : %u\n"
                        " Reads      : %u\n"
                        " Writes     : %u\n"
                        " Others     : %u\n"
                        " Disconnects: %u\n"
                        " Aborts     : %u\n"
                        " Bus resets : %u\n"
                        " Host resets: %u\n",
                        info->stats.queues,      info->stats.removes,
                        info->stats.fins,        info->stats.reads,
                        info->stats.writes,      info->stats.miscs,
                        info->stats.disconnects, info->stats.aborts,
                        info->stats.bus_resets,  info->stats.host_resets);
}

void fas216_print_devices(FAS216_Info *info, struct seq_file *m)
{
        struct fas216_device *dev;
        struct scsi_device *scd;

        seq_puts(m, "Device/Lun TaggedQ       Parity   Sync\n");

        shost_for_each_device(scd, info->host) {
                dev = &info->device[scd->id];
                seq_printf(m, "     %d/%llu   ", scd->id, scd->lun);
                if (scd->tagged_supported)
                        seq_printf(m, "%3sabled ",
                                     scd->simple_tags ? "en" : "dis");
                else
                        seq_puts(m, "unsupported   ");

                seq_printf(m, "%3sabled ", dev->parity_enabled ? "en" : "dis");

                if (dev->sof)
                        seq_printf(m, "offset %d, %d ns\n",
                                     dev->sof, dev->period * 4);
                else
                        seq_puts(m, "async\n");
        }
}

EXPORT_SYMBOL(fas216_init);
EXPORT_SYMBOL(fas216_add);
EXPORT_SYMBOL(fas216_queue_command);
EXPORT_SYMBOL(fas216_noqueue_command);
EXPORT_SYMBOL(fas216_intr);
EXPORT_SYMBOL(fas216_remove);
EXPORT_SYMBOL(fas216_release);
EXPORT_SYMBOL(fas216_eh_abort);
EXPORT_SYMBOL(fas216_eh_device_reset);
EXPORT_SYMBOL(fas216_eh_bus_reset);
EXPORT_SYMBOL(fas216_eh_host_reset);
EXPORT_SYMBOL(fas216_print_host);
EXPORT_SYMBOL(fas216_print_stats);
EXPORT_SYMBOL(fas216_print_devices);

MODULE_AUTHOR("Russell King");
MODULE_DESCRIPTION("Generic FAS216/NCR53C9x driver core");
MODULE_LICENSE("GPL");