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 // SPDX-License-Identifier: GPL-2.0
 /*
  * NCR 5380 generic driver routines.  These should make it *trivial*
  * to implement 5380 SCSI drivers under Linux with a non-trantor
  * architecture.
  *
  * Note that these routines also work with NR53c400 family chips.
  *
  * Copyright 1993, Drew Eckhardt
  * Visionary Computing
  * (Unix and Linux consulting and custom programming)
  * drew@colorado.edu
  * +1 (303) 666-5836
  *
  * For more information, please consult
  *
  * NCR 5380 Family
  * SCSI Protocol Controller
  * Databook
  *
  * NCR Microelectronics
  * 1635 Aeroplaza Drive
  * Colorado Springs, CO 80916
  * 1+ (719) 578-3400
  * 1+ (800) 334-5454
  */
 
 /*
  * With contributions from Ray Van Tassle, Ingmar Baumgart,
  * Ronald van Cuijlenborg, Alan Cox and others.
  */
 
 /* Ported to Atari by Roman Hodek and others. */
 
 /* Adapted for the Sun 3 by Sam Creasey. */
 
 /*
  * Design
  *
  * This is a generic 5380 driver.  To use it on a different platform,
  * one simply writes appropriate system specific macros (ie, data
  * transfer - some PC's will use the I/O bus, 68K's must use
  * memory mapped) and drops this file in their 'C' wrapper.
  *
  * As far as command queueing, two queues are maintained for
  * each 5380 in the system - commands that haven't been issued yet,
  * and commands that are currently executing.  This means that an
  * unlimited number of commands may be queued, letting
  * more commands propagate from the higher driver levels giving higher
  * throughput.  Note that both I_T_L and I_T_L_Q nexuses are supported,
  * allowing multiple commands to propagate all the way to a SCSI-II device
  * while a command is already executing.
  *
  *
  * Issues specific to the NCR5380 :
  *
  * When used in a PIO or pseudo-dma mode, the NCR5380 is a braindead
  * piece of hardware that requires you to sit in a loop polling for
  * the REQ signal as long as you are connected.  Some devices are
  * brain dead (ie, many TEXEL CD ROM drives) and won't disconnect
  * while doing long seek operations. [...] These
  * broken devices are the exception rather than the rule and I'd rather
  * spend my time optimizing for the normal case.
  *
  * Architecture :
  *
  * At the heart of the design is a coroutine, NCR5380_main,
  * which is started from a workqueue for each NCR5380 host in the
  * system.  It attempts to establish I_T_L or I_T_L_Q nexuses by
  * removing the commands from the issue queue and calling
  * NCR5380_select() if a nexus is not established.
  *
  * Once a nexus is established, the NCR5380_information_transfer()
  * phase goes through the various phases as instructed by the target.
  * if the target goes into MSG IN and sends a DISCONNECT message,
  * the command structure is placed into the per instance disconnected
  * queue, and NCR5380_main tries to find more work.  If the target is
  * idle for too long, the system will try to sleep.
  *
  * If a command has disconnected, eventually an interrupt will trigger,
  * calling NCR5380_intr()  which will in turn call NCR5380_reselect
  * to reestablish a nexus.  This will run main if necessary.
  *
  * On command termination, the done function will be called as
  * appropriate.
  *
  * The command data pointer is initialized after the command is connected
  * in NCR5380_select, and set as appropriate in NCR5380_information_transfer.
  * Note that in violation of the standard, an implicit SAVE POINTERS operation
  * is done, since some BROKEN disks fail to issue an explicit SAVE POINTERS.
  */
 
 /*
  * Using this file :
  * This file a skeleton Linux SCSI driver for the NCR 5380 series
  * of chips.  To use it, you write an architecture specific functions
  * and macros and include this file in your driver.
  *
  * These macros MUST be defined :
  *
  * NCR5380_read(register)  - read from the specified register
  *
  * NCR5380_write(register, value) - write to the specific register
  *
  * NCR5380_implementation_fields  - additional fields needed for this
  * specific implementation of the NCR5380
  *
  * Either real DMA *or* pseudo DMA may be implemented
  *
  * NCR5380_dma_xfer_len   - determine size of DMA/PDMA transfer
  * NCR5380_dma_send_setup - execute DMA/PDMA from memory to 5380
  * NCR5380_dma_recv_setup - execute DMA/PDMA from 5380 to memory
  * NCR5380_dma_residual   - residual byte count
  *
  * The generic driver is initialized by calling NCR5380_init(instance),
  * after setting the appropriate host specific fields and ID.
  */
 
 #ifndef NCR5380_io_delay
 #define NCR5380_io_delay(x)
 #endif
 
 #ifndef NCR5380_acquire_dma_irq
 #define NCR5380_acquire_dma_irq(x)  (1)
 #endif
 
 #ifndef NCR5380_release_dma_irq
 #define NCR5380_release_dma_irq(x)
 #endif
 
 static unsigned int disconnect_mask = ~0;
 module_param(disconnect_mask, int, 0444);
 
 static int do_abort(struct Scsi_Host *, unsigned int);
 static void do_reset(struct Scsi_Host *);
 static void bus_reset_cleanup(struct Scsi_Host *);
 
 /**
  * initialize_SCp - init the scsi pointer field
  * @cmd: command block to set up
  *
  * Set up the internal fields in the SCSI command.
  */
 
 static inline void initialize_SCp(struct scsi_cmnd *cmd)
 {
     struct NCR5380_cmd *ncmd = NCR5380_to_ncmd(cmd);
 
     if (scsi_bufflen(cmd)) {
         ncmd->buffer = scsi_sglist(cmd);
         ncmd->ptr = sg_virt(ncmd->buffer);
         ncmd->this_residual = ncmd->buffer->length;
     } else {
         ncmd->buffer = NULL;
         ncmd->ptr = NULL;
         ncmd->this_residual = 0;
     }
 
     ncmd->status = 0;
     ncmd->message = 0;
 }
 
 static inline void advance_sg_buffer(struct NCR5380_cmd *ncmd)
 {
     struct scatterlist *s = ncmd->buffer;
 
     if (!ncmd->this_residual && s && !sg_is_last(s)) {
         ncmd->buffer = sg_next(s);
         ncmd->ptr = sg_virt(ncmd->buffer);
         ncmd->this_residual = ncmd->buffer->length;
     }
 }
 
 static inline void set_resid_from_SCp(struct scsi_cmnd *cmd)
 {
     struct NCR5380_cmd *ncmd = NCR5380_to_ncmd(cmd);
     int resid = ncmd->this_residual;
     struct scatterlist *s = ncmd->buffer;
 
     if (s)
         while (!sg_is_last(s)) {
             s = sg_next(s);
             resid += s->length;
         }
     scsi_set_resid(cmd, resid);
 }
 
 /**
  * NCR5380_poll_politely2 - wait for two chip register values
  * @hostdata: host private data
  * @reg1: 5380 register to poll
  * @bit1: Bitmask to check
  * @val1: Expected value
  * @reg2: Second 5380 register to poll
  * @bit2: Second bitmask to check
  * @val2: Second expected value
  * @wait: Time-out in jiffies, 0 if sleeping is not allowed
  *
  * Polls the chip in a reasonably efficient manner waiting for an
  * event to occur. After a short quick poll we begin to yield the CPU
  * (if possible). In irq contexts the time-out is arbitrarily limited.
  * Callers may hold locks as long as they are held in irq mode.
  *
  * Returns 0 if either or both event(s) occurred otherwise -ETIMEDOUT.
  */
 
 static int NCR5380_poll_politely2(struct NCR5380_hostdata *hostdata,
                                   unsigned int reg1, u8 bit1, u8 val1,
                                   unsigned int reg2, u8 bit2, u8 val2,
                                   unsigned long wait)
 {
     unsigned long n = hostdata->poll_loops;
     unsigned long deadline = jiffies + wait;
 
     do {
         if ((NCR5380_read(reg1) & bit1) == val1)
             return 0;
         if ((NCR5380_read(reg2) & bit2) == val2)
             return 0;
         cpu_relax();
     } while (n--);
 
     if (!wait)
         return -ETIMEDOUT;
 
     /* Repeatedly sleep for 1 ms until deadline */
     while (time_is_after_jiffies(deadline)) {
         schedule_timeout_uninterruptible(1);
         if ((NCR5380_read(reg1) & bit1) == val1)
             return 0;
         if ((NCR5380_read(reg2) & bit2) == val2)
             return 0;
     }
 
     return -ETIMEDOUT;
 }
 
 #if NDEBUG
 static struct {
     unsigned char mask;
     const char *name;
 } signals[] = {
     {SR_DBP, "PARITY"},
     {SR_RST, "RST"},
     {SR_BSY, "BSY"},
     {SR_REQ, "REQ"},
     {SR_MSG, "MSG"},
     {SR_CD, "CD"},
     {SR_IO, "IO"},
     {SR_SEL, "SEL"},
     {0, NULL}
 },
 basrs[] = {
     {BASR_END_DMA_TRANSFER, "END OF DMA"},
     {BASR_DRQ, "DRQ"},
     {BASR_PARITY_ERROR, "PARITY ERROR"},
     {BASR_IRQ, "IRQ"},
     {BASR_PHASE_MATCH, "PHASE MATCH"},
     {BASR_BUSY_ERROR, "BUSY ERROR"},
     {BASR_ATN, "ATN"},
     {BASR_ACK, "ACK"},
     {0, NULL}
 },
 icrs[] = {
     {ICR_ASSERT_RST, "ASSERT RST"},
     {ICR_ARBITRATION_PROGRESS, "ARB. IN PROGRESS"},
     {ICR_ARBITRATION_LOST, "LOST ARB."},
     {ICR_ASSERT_ACK, "ASSERT ACK"},
     {ICR_ASSERT_BSY, "ASSERT BSY"},
     {ICR_ASSERT_SEL, "ASSERT SEL"},
     {ICR_ASSERT_ATN, "ASSERT ATN"},
     {ICR_ASSERT_DATA, "ASSERT DATA"},
     {0, NULL}
 },
 mrs[] = {
     {MR_BLOCK_DMA_MODE, "BLOCK DMA MODE"},
     {MR_TARGET, "TARGET"},
     {MR_ENABLE_PAR_CHECK, "PARITY CHECK"},
     {MR_ENABLE_PAR_INTR, "PARITY INTR"},
     {MR_ENABLE_EOP_INTR, "EOP INTR"},
     {MR_MONITOR_BSY, "MONITOR BSY"},
     {MR_DMA_MODE, "DMA MODE"},
     {MR_ARBITRATE, "ARBITRATE"},
     {0, NULL}
 };
 
 /**
  * NCR5380_print - print scsi bus signals
  * @instance: adapter state to dump
  *
  * Print the SCSI bus signals for debugging purposes
  */
 
 static void NCR5380_print(struct Scsi_Host *instance)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     unsigned char status, basr, mr, icr, i;
 
     status = NCR5380_read(STATUS_REG);
     mr = NCR5380_read(MODE_REG);
     icr = NCR5380_read(INITIATOR_COMMAND_REG);
     basr = NCR5380_read(BUS_AND_STATUS_REG);
 
     printk(KERN_DEBUG "SR =   0x%02x : ", status);
     for (i = 0; signals[i].mask; ++i)
         if (status & signals[i].mask)
             printk(KERN_CONT "%s, ", signals[i].name);
     printk(KERN_CONT "\nBASR = 0x%02x : ", basr);
     for (i = 0; basrs[i].mask; ++i)
         if (basr & basrs[i].mask)
             printk(KERN_CONT "%s, ", basrs[i].name);
     printk(KERN_CONT "\nICR =  0x%02x : ", icr);
     for (i = 0; icrs[i].mask; ++i)
         if (icr & icrs[i].mask)
             printk(KERN_CONT "%s, ", icrs[i].name);
     printk(KERN_CONT "\nMR =   0x%02x : ", mr);
     for (i = 0; mrs[i].mask; ++i)
         if (mr & mrs[i].mask)
             printk(KERN_CONT "%s, ", mrs[i].name);
     printk(KERN_CONT "\n");
 }
 
 static struct {
     unsigned char value;
     const char *name;
 } phases[] = {
     {PHASE_DATAOUT, "DATAOUT"},
     {PHASE_DATAIN, "DATAIN"},
     {PHASE_CMDOUT, "CMDOUT"},
     {PHASE_STATIN, "STATIN"},
     {PHASE_MSGOUT, "MSGOUT"},
     {PHASE_MSGIN, "MSGIN"},
     {PHASE_UNKNOWN, "UNKNOWN"}
 };
 
 /**
  * NCR5380_print_phase - show SCSI phase
  * @instance: adapter to dump
  *
  * Print the current SCSI phase for debugging purposes
  */
 
 static void NCR5380_print_phase(struct Scsi_Host *instance)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     unsigned char status;
     int i;
 
     status = NCR5380_read(STATUS_REG);
     if (!(status & SR_REQ))
         shost_printk(KERN_DEBUG, instance, "REQ not asserted, phase unknown.\n");
     else {
         for (i = 0; (phases[i].value != PHASE_UNKNOWN) &&
              (phases[i].value != (status & PHASE_MASK)); ++i)
             ;
         shost_printk(KERN_DEBUG, instance, "phase %s\n", phases[i].name);
     }
 }
 #endif
 
 /**
  * NCR5380_info - report driver and host information
  * @instance: relevant scsi host instance
  *
  * For use as the host template info() handler.
  */
 
 static const char *NCR5380_info(struct Scsi_Host *instance)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
 
     return hostdata->info;
 }
 
 /**
  * NCR5380_init - initialise an NCR5380
  * @instance: adapter to configure
  * @flags: control flags
  *
  * Initializes *instance and corresponding 5380 chip,
  * with flags OR'd into the initial flags value.
  *
  * Notes : I assume that the host, hostno, and id bits have been
  * set correctly. I don't care about the irq and other fields.
  *
  * Returns 0 for success
  */
 
 static int NCR5380_init(struct Scsi_Host *instance, int flags)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     int i;
     unsigned long deadline;
     unsigned long accesses_per_ms;
 
     instance->max_lun = 7;
 
     hostdata->host = instance;
     hostdata->id_mask = 1 << instance->this_id;
     hostdata->id_higher_mask = 0;
     for (i = hostdata->id_mask; i <= 0x80; i <<= 1)
         if (i > hostdata->id_mask)
             hostdata->id_higher_mask |= i;
     for (i = 0; i < 8; ++i)
         hostdata->busy[i] = 0;
     hostdata->dma_len = 0;
 
     spin_lock_init(&hostdata->lock);
     hostdata->connected = NULL;
     hostdata->sensing = NULL;
     INIT_LIST_HEAD(&hostdata->autosense);
     INIT_LIST_HEAD(&hostdata->unissued);
     INIT_LIST_HEAD(&hostdata->disconnected);
 
     hostdata->flags = flags;
 
     INIT_WORK(&hostdata->main_task, NCR5380_main);
     hostdata->work_q = alloc_workqueue("ncr5380_%d",
                             WQ_UNBOUND | WQ_MEM_RECLAIM,
                             1, instance->host_no);
     if (!hostdata->work_q)
         return -ENOMEM;
 
     snprintf(hostdata->info, sizeof(hostdata->info),
         "%s, irq %d, io_port 0x%lx, base 0x%lx, can_queue %d, cmd_per_lun %d, sg_tablesize %d, this_id %d, flags { %s%s%s}",
         instance->hostt->name, instance->irq, hostdata->io_port,
         hostdata->base, instance->can_queue, instance->cmd_per_lun,
         instance->sg_tablesize, instance->this_id,
         hostdata->flags & FLAG_DMA_FIXUP     ? "DMA_FIXUP "     : "",
         hostdata->flags & FLAG_NO_PSEUDO_DMA ? "NO_PSEUDO_DMA " : "",
         hostdata->flags & FLAG_TOSHIBA_DELAY ? "TOSHIBA_DELAY " : "");
 
     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
     NCR5380_write(MODE_REG, MR_BASE);
     NCR5380_write(TARGET_COMMAND_REG, 0);
     NCR5380_write(SELECT_ENABLE_REG, 0);
 
     /* Calibrate register polling loop */
     i = 0;
     deadline = jiffies + 1;
     do {
         cpu_relax();
     } while (time_is_after_jiffies(deadline));
     deadline += msecs_to_jiffies(256);
     do {
         NCR5380_read(STATUS_REG);
         ++i;
         cpu_relax();
     } while (time_is_after_jiffies(deadline));
     accesses_per_ms = i / 256;
     hostdata->poll_loops = NCR5380_REG_POLL_TIME * accesses_per_ms / 2;
 
     return 0;
 }
 
 /**
  * NCR5380_maybe_reset_bus - Detect and correct bus wedge problems.
  * @instance: adapter to check
  *
  * If the system crashed, it may have crashed with a connected target and
  * the SCSI bus busy. Check for BUS FREE phase. If not, try to abort the
  * currently established nexus, which we know nothing about. Failing that
  * do a bus reset.
  *
  * Note that a bus reset will cause the chip to assert IRQ.
  *
  * Returns 0 if successful, otherwise -ENXIO.
  */
 
 static int NCR5380_maybe_reset_bus(struct Scsi_Host *instance)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     int pass;
 
     for (pass = 1; (NCR5380_read(STATUS_REG) & SR_BSY) && pass <= 6; ++pass) {
         switch (pass) {
         case 1:
         case 3:
         case 5:
             shost_printk(KERN_ERR, instance, "SCSI bus busy, waiting up to five seconds\n");
             NCR5380_poll_politely(hostdata,
                                   STATUS_REG, SR_BSY, 0, 5 * HZ);
             break;
         case 2:
             shost_printk(KERN_ERR, instance, "bus busy, attempting abort\n");
             do_abort(instance, 1);
             break;
         case 4:
             shost_printk(KERN_ERR, instance, "bus busy, attempting reset\n");
             do_reset(instance);
             /* Wait after a reset; the SCSI standard calls for
              * 250ms, we wait 500ms to be on the safe side.
              * But some Toshiba CD-ROMs need ten times that.
              */
             if (hostdata->flags & FLAG_TOSHIBA_DELAY)
                 msleep(2500);
             else
                 msleep(500);
             break;
         case 6:
             shost_printk(KERN_ERR, instance, "bus locked solid\n");
             return -ENXIO;
         }
     }
     return 0;
 }
 
 /**
  * NCR5380_exit - remove an NCR5380
  * @instance: adapter to remove
  *
  * Assumes that no more work can be queued (e.g. by NCR5380_intr).
  */
 
 static void NCR5380_exit(struct Scsi_Host *instance)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
 
     cancel_work_sync(&hostdata->main_task);
     destroy_workqueue(hostdata->work_q);
 }
 
 /**
  * complete_cmd - finish processing a command and return it to the SCSI ML
  * @instance: the host instance
  * @cmd: command to complete
  */
 
 static void complete_cmd(struct Scsi_Host *instance,
                          struct scsi_cmnd *cmd)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
 
     dsprintk(NDEBUG_QUEUES, instance, "complete_cmd: cmd %p\n", cmd);
 
     if (hostdata->sensing == cmd) {
         /* Autosense processing ends here */
         if (get_status_byte(cmd) != SAM_STAT_GOOD) {
             scsi_eh_restore_cmnd(cmd, &hostdata->ses);
         } else {
             scsi_eh_restore_cmnd(cmd, &hostdata->ses);
             set_status_byte(cmd, SAM_STAT_CHECK_CONDITION);
         }
         hostdata->sensing = NULL;
     }
 
     scsi_done(cmd);
 }
 
 /**
  * NCR5380_queue_command - queue a command
  * @instance: the relevant SCSI adapter
  * @cmd: SCSI command
  *
  * cmd is added to the per-instance issue queue, with minor
  * twiddling done to the host specific fields of cmd.  If the
  * main coroutine is not running, it is restarted.
  */
 
 static int NCR5380_queue_command(struct Scsi_Host *instance,
                                  struct scsi_cmnd *cmd)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     struct NCR5380_cmd *ncmd = NCR5380_to_ncmd(cmd);
     unsigned long flags;
 
 #if (NDEBUG & NDEBUG_NO_WRITE)
     switch (cmd->cmnd[0]) {
     case WRITE_6:
     case WRITE_10:
         shost_printk(KERN_DEBUG, instance, "WRITE attempted with NDEBUG_NO_WRITE set\n");
         cmd->result = (DID_ERROR << 16);
         scsi_done(cmd);
         return 0;
     }
 #endif /* (NDEBUG & NDEBUG_NO_WRITE) */
 
     cmd->result = 0;
 
     spin_lock_irqsave(&hostdata->lock, flags);
 
     if (!NCR5380_acquire_dma_irq(instance)) {
         spin_unlock_irqrestore(&hostdata->lock, flags);
 
         return SCSI_MLQUEUE_HOST_BUSY;
     }
 
     /*
      * Insert the cmd into the issue queue. Note that REQUEST SENSE
      * commands are added to the head of the queue since any command will
      * clear the contingent allegiance condition that exists and the
      * sense data is only guaranteed to be valid while the condition exists.
      */
 
     if (cmd->cmnd[0] == REQUEST_SENSE)
         list_add(&ncmd->list, &hostdata->unissued);
     else
         list_add_tail(&ncmd->list, &hostdata->unissued);
 
     spin_unlock_irqrestore(&hostdata->lock, flags);
 
     dsprintk(NDEBUG_QUEUES, instance, "command %p added to %s of queue\n",
              cmd, (cmd->cmnd[0] == REQUEST_SENSE) ? "head" : "tail");
 
     /* Kick off command processing */
     queue_work(hostdata->work_q, &hostdata->main_task);
     return 0;
 }
 
 static inline void maybe_release_dma_irq(struct Scsi_Host *instance)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
 
     /* Caller does the locking needed to set & test these data atomically */
     if (list_empty(&hostdata->disconnected) &&
         list_empty(&hostdata->unissued) &&
         list_empty(&hostdata->autosense) &&
         !hostdata->connected &&
         !hostdata->selecting) {
         NCR5380_release_dma_irq(instance);
     }
 }
 
 /**
  * dequeue_next_cmd - dequeue a command for processing
  * @instance: the scsi host instance
  *
  * Priority is given to commands on the autosense queue. These commands
  * need autosense because of a CHECK CONDITION result.
  *
  * Returns a command pointer if a command is found for a target that is
  * not already busy. Otherwise returns NULL.
  */
 
 static struct scsi_cmnd *dequeue_next_cmd(struct Scsi_Host *instance)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     struct NCR5380_cmd *ncmd;
     struct scsi_cmnd *cmd;
 
     if (hostdata->sensing || list_empty(&hostdata->autosense)) {
         list_for_each_entry(ncmd, &hostdata->unissued, list) {
             cmd = NCR5380_to_scmd(ncmd);
             dsprintk(NDEBUG_QUEUES, instance, "dequeue: cmd=%p target=%d busy=0x%02x lun=%llu\n",
                      cmd, scmd_id(cmd), hostdata->busy[scmd_id(cmd)], cmd->device->lun);
 
             if (!(hostdata->busy[scmd_id(cmd)] & (1 << cmd->device->lun))) {
                 list_del(&ncmd->list);
                 dsprintk(NDEBUG_QUEUES, instance,
                          "dequeue: removed %p from issue queue\n", cmd);
                 return cmd;
             }
         }
     } else {
         /* Autosense processing begins here */
         ncmd = list_first_entry(&hostdata->autosense,
                                 struct NCR5380_cmd, list);
         list_del(&ncmd->list);
         cmd = NCR5380_to_scmd(ncmd);
         dsprintk(NDEBUG_QUEUES, instance,
                  "dequeue: removed %p from autosense queue\n", cmd);
         scsi_eh_prep_cmnd(cmd, &hostdata->ses, NULL, 0, ~0);
         hostdata->sensing = cmd;
         return cmd;
     }
     return NULL;
 }
 
 static void requeue_cmd(struct Scsi_Host *instance, struct scsi_cmnd *cmd)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     struct NCR5380_cmd *ncmd = NCR5380_to_ncmd(cmd);
 
     if (hostdata->sensing == cmd) {
         scsi_eh_restore_cmnd(cmd, &hostdata->ses);
         list_add(&ncmd->list, &hostdata->autosense);
         hostdata->sensing = NULL;
     } else
         list_add(&ncmd->list, &hostdata->unissued);
 }
 
 /**
  * NCR5380_main - NCR state machines
  *
  * NCR5380_main is a coroutine that runs as long as more work can
  * be done on the NCR5380 host adapters in a system.  Both
  * NCR5380_queue_command() and NCR5380_intr() will try to start it
  * in case it is not running.
  */
 
 static void NCR5380_main(struct work_struct *work)
 {
     struct NCR5380_hostdata *hostdata =
         container_of(work, struct NCR5380_hostdata, main_task);
     struct Scsi_Host *instance = hostdata->host;
     int done;
 
     do {
         done = 1;
 
         spin_lock_irq(&hostdata->lock);
         while (!hostdata->connected && !hostdata->selecting) {
             struct scsi_cmnd *cmd = dequeue_next_cmd(instance);
 
             if (!cmd)
                 break;
 
             dsprintk(NDEBUG_MAIN, instance, "main: dequeued %p\n", cmd);
 
             /*
              * Attempt to establish an I_T_L nexus here.
              * On success, instance->hostdata->connected is set.
              * On failure, we must add the command back to the
              * issue queue so we can keep trying.
              */
             /*
              * REQUEST SENSE commands are issued without tagged
              * queueing, even on SCSI-II devices because the
              * contingent allegiance condition exists for the
              * entire unit.
              */
 
             if (!NCR5380_select(instance, cmd)) {
                 dsprintk(NDEBUG_MAIN, instance, "main: select complete\n");
             } else {
                 dsprintk(NDEBUG_MAIN | NDEBUG_QUEUES, instance,
                          "main: select failed, returning %p to queue\n", cmd);
                 requeue_cmd(instance, cmd);
             }
         }
         if (hostdata->connected && !hostdata->dma_len) {
             dsprintk(NDEBUG_MAIN, instance, "main: performing information transfer\n");
             NCR5380_information_transfer(instance);
             done = 0;
         }
         if (!hostdata->connected) {
             NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
             maybe_release_dma_irq(instance);
         }
         spin_unlock_irq(&hostdata->lock);
         if (!done)
             cond_resched();
     } while (!done);
 }
 
 /*
  * NCR5380_dma_complete - finish DMA transfer
  * @instance: the scsi host instance
  *
  * Called by the interrupt handler when DMA finishes or a phase
  * mismatch occurs (which would end the DMA transfer).
  */
 
 static void NCR5380_dma_complete(struct Scsi_Host *instance)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     struct NCR5380_cmd *ncmd = NCR5380_to_ncmd(hostdata->connected);
     int transferred;
     unsigned char **data;
     int *count;
     int saved_data = 0, overrun = 0;
     unsigned char p;
 
     if (hostdata->read_overruns) {
         p = ncmd->phase;
         if (p & SR_IO) {
             udelay(10);
             if ((NCR5380_read(BUS_AND_STATUS_REG) &
                  (BASR_PHASE_MATCH | BASR_ACK)) ==
                 (BASR_PHASE_MATCH | BASR_ACK)) {
                 saved_data = NCR5380_read(INPUT_DATA_REG);
                 overrun = 1;
                 dsprintk(NDEBUG_DMA, instance, "read overrun handled\n");
             }
         }
     }
 
 #ifdef CONFIG_SUN3
     if (sun3scsi_dma_finish(hostdata->connected->sc_data_direction)) {
         pr_err("scsi%d: overrun in UDC counter -- not prepared to deal with this!\n",
                instance->host_no);
         BUG();
     }
 
     if ((NCR5380_read(BUS_AND_STATUS_REG) & (BASR_PHASE_MATCH | BASR_ACK)) ==
         (BASR_PHASE_MATCH | BASR_ACK)) {
         pr_err("scsi%d: BASR %02x\n", instance->host_no,
                NCR5380_read(BUS_AND_STATUS_REG));
         pr_err("scsi%d: bus stuck in data phase -- probably a single byte overrun!\n",
                instance->host_no);
         BUG();
     }
 #endif
 
     NCR5380_write(MODE_REG, MR_BASE);
     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
     NCR5380_read(RESET_PARITY_INTERRUPT_REG);
 
     transferred = hostdata->dma_len - NCR5380_dma_residual(hostdata);
     hostdata->dma_len = 0;
 
     data = (unsigned char **)&ncmd->ptr;
     count = &ncmd->this_residual;
     *data += transferred;
     *count -= transferred;
 
     if (hostdata->read_overruns) {
         int cnt, toPIO;
 
         if ((NCR5380_read(STATUS_REG) & PHASE_MASK) == p && (p & SR_IO)) {
             cnt = toPIO = hostdata->read_overruns;
             if (overrun) {
                 dsprintk(NDEBUG_DMA, instance,
                          "Got an input overrun, using saved byte\n");
                 *(*data)++ = saved_data;
                 (*count)--;
                 cnt--;
                 toPIO--;
             }
             if (toPIO > 0) {
                 dsprintk(NDEBUG_DMA, instance,
                          "Doing %d byte PIO to 0x%p\n", cnt, *data);
                 NCR5380_transfer_pio(instance, &p, &cnt, data, 0);
                 *count -= toPIO - cnt;
             }
         }
     }
 }
 
 /**
  * NCR5380_intr - generic NCR5380 irq handler
  * @irq: interrupt number
  * @dev_id: device info
  *
  * Handle interrupts, reestablishing I_T_L or I_T_L_Q nexuses
  * from the disconnected queue, and restarting NCR5380_main()
  * as required.
  *
  * The chip can assert IRQ in any of six different conditions. The IRQ flag
  * is then cleared by reading the Reset Parity/Interrupt Register (RPIR).
  * Three of these six conditions are latched in the Bus and Status Register:
  * - End of DMA (cleared by ending DMA Mode)
  * - Parity error (cleared by reading RPIR)
  * - Loss of BSY (cleared by reading RPIR)
  * Two conditions have flag bits that are not latched:
  * - Bus phase mismatch (non-maskable in DMA Mode, cleared by ending DMA Mode)
  * - Bus reset (non-maskable)
  * The remaining condition has no flag bit at all:
  * - Selection/reselection
  *
  * Hence, establishing the cause(s) of any interrupt is partly guesswork.
  * In "The DP8490 and DP5380 Comparison Guide", National Semiconductor
  * claimed that "the design of the [DP8490] interrupt logic ensures
  * interrupts will not be lost (they can be on the DP5380)."
  * The L5380/53C80 datasheet from LOGIC Devices has more details.
  *
  * Checking for bus reset by reading RST is futile because of interrupt
  * latency, but a bus reset will reset chip logic. Checking for parity error
  * is unnecessary because that interrupt is never enabled. A Loss of BSY
  * condition will clear DMA Mode. We can tell when this occurs because the
  * the Busy Monitor interrupt is enabled together with DMA Mode.
  */
 
 static irqreturn_t __maybe_unused NCR5380_intr(int irq, void *dev_id)
 {
     struct Scsi_Host *instance = dev_id;
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     int handled = 0;
     unsigned char basr;
     unsigned long flags;
 
     spin_lock_irqsave(&hostdata->lock, flags);
 
     basr = NCR5380_read(BUS_AND_STATUS_REG);
     if (basr & BASR_IRQ) {
         unsigned char mr = NCR5380_read(MODE_REG);
         unsigned char sr = NCR5380_read(STATUS_REG);
 
         dsprintk(NDEBUG_INTR, instance, "IRQ %d, BASR 0x%02x, SR 0x%02x, MR 0x%02x\n",
                  irq, basr, sr, mr);
 
         if ((mr & MR_DMA_MODE) || (mr & MR_MONITOR_BSY)) {
             /* Probably End of DMA, Phase Mismatch or Loss of BSY.
              * We ack IRQ after clearing Mode Register. Workarounds
              * for End of DMA errata need to happen in DMA Mode.
              */
 
             dsprintk(NDEBUG_INTR, instance, "interrupt in DMA mode\n");
 
             if (hostdata->connected) {
                 NCR5380_dma_complete(instance);
                 queue_work(hostdata->work_q, &hostdata->main_task);
             } else {
                 NCR5380_write(MODE_REG, MR_BASE);
                 NCR5380_read(RESET_PARITY_INTERRUPT_REG);
             }
         } else if ((NCR5380_read(CURRENT_SCSI_DATA_REG) & hostdata->id_mask) &&
             (sr & (SR_SEL | SR_IO | SR_BSY | SR_RST)) == (SR_SEL | SR_IO)) {
             /* Probably reselected */
             NCR5380_write(SELECT_ENABLE_REG, 0);
             NCR5380_read(RESET_PARITY_INTERRUPT_REG);
 
             dsprintk(NDEBUG_INTR, instance, "interrupt with SEL and IO\n");
 
             if (!hostdata->connected) {
                 NCR5380_reselect(instance);
                 queue_work(hostdata->work_q, &hostdata->main_task);
             }
             if (!hostdata->connected)
                 NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
         } else {
             /* Probably Bus Reset */
             NCR5380_read(RESET_PARITY_INTERRUPT_REG);
 
             if (sr & SR_RST) {
                 /* Certainly Bus Reset */
                 shost_printk(KERN_WARNING, instance,
                          "bus reset interrupt\n");
                 bus_reset_cleanup(instance);
             } else {
                 dsprintk(NDEBUG_INTR, instance, "unknown interrupt\n");
             }
 #ifdef SUN3_SCSI_VME
             dregs->csr |= CSR_DMA_ENABLE;
 #endif
         }
         handled = 1;
     } else {
         dsprintk(NDEBUG_INTR, instance, "interrupt without IRQ bit\n");
 #ifdef SUN3_SCSI_VME
         dregs->csr |= CSR_DMA_ENABLE;
 #endif
     }
 
     spin_unlock_irqrestore(&hostdata->lock, flags);
 
     return IRQ_RETVAL(handled);
 }
 
 /**
  * NCR5380_select - attempt arbitration and selection for a given command
  * @instance: the Scsi_Host instance
  * @cmd: the scsi_cmnd to execute
  *
  * This routine establishes an I_T_L nexus for a SCSI command. This involves
  * ARBITRATION, SELECTION and MESSAGE OUT phases and an IDENTIFY message.
  *
  * Returns true if the operation should be retried.
  * Returns false if it should not be retried.
  *
  * Side effects :
  * If bus busy, arbitration failed, etc, NCR5380_select() will exit
  * with registers as they should have been on entry - ie
  * SELECT_ENABLE will be set appropriately, the NCR5380
  * will cease to drive any SCSI bus signals.
  *
  * If successful : the I_T_L nexus will be established, and
  * hostdata->connected will be set to cmd.
  * SELECT interrupt will be disabled.
  *
  * If failed (no target) : scsi_done() will be called, and the
  * cmd->result host byte set to DID_BAD_TARGET.
  */
 
 static bool NCR5380_select(struct Scsi_Host *instance, struct scsi_cmnd *cmd)
     __releases(&hostdata->lock) __acquires(&hostdata->lock)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     unsigned char tmp[3], phase;
     unsigned char *data;
     int len;
     int err;
     bool ret = true;
     bool can_disconnect = instance->irq != NO_IRQ &&
                   cmd->cmnd[0] != REQUEST_SENSE &&
                   (disconnect_mask & BIT(scmd_id(cmd)));
 
     NCR5380_dprint(NDEBUG_ARBITRATION, instance);
     dsprintk(NDEBUG_ARBITRATION, instance, "starting arbitration, id = %d\n",
              instance->this_id);
 
     /*
      * Arbitration and selection phases are slow and involve dropping the
      * lock, so we have to watch out for EH. An exception handler may
      * change 'selecting' to NULL. This function will then return false
      * so that the caller will forget about 'cmd'. (During information
      * transfer phases, EH may change 'connected' to NULL.)
      */
     hostdata->selecting = cmd;
 
     /*
      * Set the phase bits to 0, otherwise the NCR5380 won't drive the
      * data bus during SELECTION.
      */
 
     NCR5380_write(TARGET_COMMAND_REG, 0);
 
     /*
      * Start arbitration.
      */
 
     NCR5380_write(OUTPUT_DATA_REG, hostdata->id_mask);
     NCR5380_write(MODE_REG, MR_ARBITRATE);
 
     /* The chip now waits for BUS FREE phase. Then after the 800 ns
      * Bus Free Delay, arbitration will begin.
      */
 
     spin_unlock_irq(&hostdata->lock);
     err = NCR5380_poll_politely2(hostdata, MODE_REG, MR_ARBITRATE, 0,
                     INITIATOR_COMMAND_REG, ICR_ARBITRATION_PROGRESS,
                                            ICR_ARBITRATION_PROGRESS, HZ);
     spin_lock_irq(&hostdata->lock);
     if (!(NCR5380_read(MODE_REG) & MR_ARBITRATE)) {
         /* Reselection interrupt */
         goto out;
     }
     if (!hostdata->selecting) {
         /* Command was aborted */
         NCR5380_write(MODE_REG, MR_BASE);
         return false;
     }
     if (err < 0) {
         NCR5380_write(MODE_REG, MR_BASE);
         shost_printk(KERN_ERR, instance,
                      "select: arbitration timeout\n");
         goto out;
     }
     spin_unlock_irq(&hostdata->lock);
 
     /* The SCSI-2 arbitration delay is 2.4 us */
     udelay(3);
 
     /* Check for lost arbitration */
     if ((NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST) ||
         (NCR5380_read(CURRENT_SCSI_DATA_REG) & hostdata->id_higher_mask) ||
         (NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST)) {
         NCR5380_write(MODE_REG, MR_BASE);
         dsprintk(NDEBUG_ARBITRATION, instance, "lost arbitration, deasserting MR_ARBITRATE\n");
         spin_lock_irq(&hostdata->lock);
         goto out;
     }
 
     /* After/during arbitration, BSY should be asserted.
      * IBM DPES-31080 Version S31Q works now
      * Tnx to Thomas_Roesch@m2.maus.de for finding this! (Roman)
      */
     NCR5380_write(INITIATOR_COMMAND_REG,
               ICR_BASE | ICR_ASSERT_SEL | ICR_ASSERT_BSY);
 
     /*
      * Again, bus clear + bus settle time is 1.2us, however, this is
      * a minimum so we'll udelay ceil(1.2)
      */
 
     if (hostdata->flags & FLAG_TOSHIBA_DELAY)
         udelay(15);
     else
         udelay(2);
 
     spin_lock_irq(&hostdata->lock);
 
     /* NCR5380_reselect() clears MODE_REG after a reselection interrupt */
     if (!(NCR5380_read(MODE_REG) & MR_ARBITRATE))
         goto out;
 
     if (!hostdata->selecting) {
         NCR5380_write(MODE_REG, MR_BASE);
         NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
         return false;
     }
 
     dsprintk(NDEBUG_ARBITRATION, instance, "won arbitration\n");
 
     /*
      * Now that we have won arbitration, start Selection process, asserting
      * the host and target ID's on the SCSI bus.
      */
 
     NCR5380_write(OUTPUT_DATA_REG, hostdata->id_mask | (1 << scmd_id(cmd)));
 
     /*
      * Raise ATN while SEL is true before BSY goes false from arbitration,
      * since this is the only way to guarantee that we'll get a MESSAGE OUT
      * phase immediately after selection.
      */
 
     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_BSY |
                   ICR_ASSERT_DATA | ICR_ASSERT_ATN | ICR_ASSERT_SEL);
     NCR5380_write(MODE_REG, MR_BASE);
 
     /*
      * Reselect interrupts must be turned off prior to the dropping of BSY,
      * otherwise we will trigger an interrupt.
      */
     NCR5380_write(SELECT_ENABLE_REG, 0);
 
     spin_unlock_irq(&hostdata->lock);
 
     /*
      * The initiator shall then wait at least two deskew delays and release
      * the BSY signal.
      */
     udelay(1);        /* wingel -- wait two bus deskew delay >2*45ns */
 
     /* Reset BSY */
     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_DATA |
                   ICR_ASSERT_ATN | ICR_ASSERT_SEL);
 
     /*
      * Something weird happens when we cease to drive BSY - looks
      * like the board/chip is letting us do another read before the
      * appropriate propagation delay has expired, and we're confusing
      * a BSY signal from ourselves as the target's response to SELECTION.
      *
      * A small delay (the 'C++' frontend breaks the pipeline with an
      * unnecessary jump, making it work on my 386-33/Trantor T128, the
      * tighter 'C' code breaks and requires this) solves the problem -
      * the 1 us delay is arbitrary, and only used because this delay will
      * be the same on other platforms and since it works here, it should
      * work there.
      *
      * wingel suggests that this could be due to failing to wait
      * one deskew delay.
      */
 
     udelay(1);
 
     dsprintk(NDEBUG_SELECTION, instance, "selecting target %d\n", scmd_id(cmd));
 
     /*
      * The SCSI specification calls for a 250 ms timeout for the actual
      * selection.
      */
 
     err = NCR5380_poll_politely(hostdata, STATUS_REG, SR_BSY, SR_BSY,
                                 msecs_to_jiffies(250));
 
     if ((NCR5380_read(STATUS_REG) & (SR_SEL | SR_IO)) == (SR_SEL | SR_IO)) {
         spin_lock_irq(&hostdata->lock);
         NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
         NCR5380_reselect(instance);
         shost_printk(KERN_ERR, instance, "reselection after won arbitration?\n");
         goto out;
     }
 
     if (err < 0) {
         spin_lock_irq(&hostdata->lock);
         NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
 
         /* Can't touch cmd if it has been reclaimed by the scsi ML */
         if (!hostdata->selecting)
             return false;
 
         cmd->result = DID_BAD_TARGET << 16;
         complete_cmd(instance, cmd);
         dsprintk(NDEBUG_SELECTION, instance,
             "target did not respond within 250ms\n");
         ret = false;
         goto out;
     }
 
     /*
      * No less than two deskew delays after the initiator detects the
      * BSY signal is true, it shall release the SEL signal and may
      * change the DATA BUS.                                     -wingel
      */
 
     udelay(1);
 
     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
 
     /*
      * Since we followed the SCSI spec, and raised ATN while SEL
      * was true but before BSY was false during selection, the information
      * transfer phase should be a MESSAGE OUT phase so that we can send the
      * IDENTIFY message.
      */
 
     /* Wait for start of REQ/ACK handshake */
 
     err = NCR5380_poll_politely(hostdata, STATUS_REG, SR_REQ, SR_REQ, HZ);
     spin_lock_irq(&hostdata->lock);
     if (err < 0) {
         shost_printk(KERN_ERR, instance, "select: REQ timeout\n");
         NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
         goto out;
     }
     if (!hostdata->selecting) {
         do_abort(instance, 0);
         return false;
     }
 
     dsprintk(NDEBUG_SELECTION, instance, "target %d selected, going into MESSAGE OUT phase.\n",
              scmd_id(cmd));
     tmp[0] = IDENTIFY(can_disconnect, cmd->device->lun);
 
     len = 1;
     data = tmp;
     phase = PHASE_MSGOUT;
     NCR5380_transfer_pio(instance, &phase, &len, &data, 0);
     if (len) {
         NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
         cmd->result = DID_ERROR << 16;
         complete_cmd(instance, cmd);
         dsprintk(NDEBUG_SELECTION, instance, "IDENTIFY message transfer failed\n");
         ret = false;
         goto out;
     }
 
     dsprintk(NDEBUG_SELECTION, instance, "nexus established.\n");
 
     hostdata->connected = cmd;
     hostdata->busy[cmd->device->id] |= 1 << cmd->device->lun;
 
 #ifdef SUN3_SCSI_VME
     dregs->csr |= CSR_INTR;
 #endif
 
     initialize_SCp(cmd);
 
     ret = false;
 
 out:
     if (!hostdata->selecting)
         return false;
     hostdata->selecting = NULL;
     return ret;
 }
 
 /*
  * Function : int NCR5380_transfer_pio (struct Scsi_Host *instance,
  * unsigned char *phase, int *count, unsigned char **data)
  *
  * Purpose : transfers data in given phase using polled I/O
  *
  * Inputs : instance - instance of driver, *phase - pointer to
  * what phase is expected, *count - pointer to number of
  * bytes to transfer, **data - pointer to data pointer,
  * can_sleep - 1 or 0 when sleeping is permitted or not, respectively.
  *
  * Returns : -1 when different phase is entered without transferring
  * maximum number of bytes, 0 if all bytes are transferred or exit
  * is in same phase.
  *
  * Also, *phase, *count, *data are modified in place.
  *
  * XXX Note : handling for bus free may be useful.
  */
 
 /*
  * Note : this code is not as quick as it could be, however it
  * IS 100% reliable, and for the actual data transfer where speed
  * counts, we will always do a pseudo DMA or DMA transfer.
  */
 
 static int NCR5380_transfer_pio(struct Scsi_Host *instance,
                 unsigned char *phase, int *count,
                 unsigned char **data, unsigned int can_sleep)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     unsigned char p = *phase, tmp;
     int c = *count;
     unsigned char *d = *data;
 
     /*
      * The NCR5380 chip will only drive the SCSI bus when the
      * phase specified in the appropriate bits of the TARGET COMMAND
      * REGISTER match the STATUS REGISTER
      */
 
     NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(p));
 
     do {
         /*
          * Wait for assertion of REQ, after which the phase bits will be
          * valid
          */
 
         if (NCR5380_poll_politely(hostdata, STATUS_REG, SR_REQ, SR_REQ,
                       HZ * can_sleep) < 0)
             break;
 
         dsprintk(NDEBUG_HANDSHAKE, instance, "REQ asserted\n");
 
         /* Check for phase mismatch */
         if ((NCR5380_read(STATUS_REG) & PHASE_MASK) != p) {
             dsprintk(NDEBUG_PIO, instance, "phase mismatch\n");
             NCR5380_dprint_phase(NDEBUG_PIO, instance);
             break;
         }
 
         /* Do actual transfer from SCSI bus to / from memory */
         if (!(p & SR_IO))
             NCR5380_write(OUTPUT_DATA_REG, *d);
         else
             *d = NCR5380_read(CURRENT_SCSI_DATA_REG);
 
         ++d;
 
         /*
          * The SCSI standard suggests that in MSGOUT phase, the initiator
          * should drop ATN on the last byte of the message phase
          * after REQ has been asserted for the handshake but before
          * the initiator raises ACK.
          */
 
         if (!(p & SR_IO)) {
             if (!((p & SR_MSG) && c > 1)) {
                 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_DATA);
                 NCR5380_dprint(NDEBUG_PIO, instance);
                 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE |
                               ICR_ASSERT_DATA | ICR_ASSERT_ACK);
             } else {
                 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE |
                               ICR_ASSERT_DATA | ICR_ASSERT_ATN);
                 NCR5380_dprint(NDEBUG_PIO, instance);
                 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE |
                               ICR_ASSERT_DATA | ICR_ASSERT_ATN | ICR_ASSERT_ACK);
             }
         } else {
             NCR5380_dprint(NDEBUG_PIO, instance);
             NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ACK);
         }
 
         if (NCR5380_poll_politely(hostdata,
                                   STATUS_REG, SR_REQ, 0, 5 * HZ * can_sleep) < 0)
             break;
 
         dsprintk(NDEBUG_HANDSHAKE, instance, "REQ negated, handshake complete\n");
 
 /*
  * We have several special cases to consider during REQ/ACK handshaking :
  * 1.  We were in MSGOUT phase, and we are on the last byte of the
  * message.  ATN must be dropped as ACK is dropped.
  *
  * 2.  We are in a MSGIN phase, and we are on the last byte of the
  * message.  We must exit with ACK asserted, so that the calling
  * code may raise ATN before dropping ACK to reject the message.
  *
  * 3.  ACK and ATN are clear and the target may proceed as normal.
  */
         if (!(p == PHASE_MSGIN && c == 1)) {
             if (p == PHASE_MSGOUT && c > 1)
                 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
             else
                 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
         }
     } while (--c);
 
     dsprintk(NDEBUG_PIO, instance, "residual %d\n", c);
 
     *count = c;
     *data = d;
     tmp = NCR5380_read(STATUS_REG);
     /* The phase read from the bus is valid if either REQ is (already)
      * asserted or if ACK hasn't been released yet. The latter applies if
      * we're in MSG IN, DATA IN or STATUS and all bytes have been received.
      */
     if ((tmp & SR_REQ) || ((tmp & SR_IO) && c == 0))
         *phase = tmp & PHASE_MASK;
     else
         *phase = PHASE_UNKNOWN;
 
     if (!c || (*phase == p))
         return 0;
     else
         return -1;
 }
 
 /**
  * do_reset - issue a reset command
  * @instance: adapter to reset
  *
  * Issue a reset sequence to the NCR5380 and try and get the bus
  * back into sane shape.
  *
  * This clears the reset interrupt flag because there may be no handler for
  * it. When the driver is initialized, the NCR5380_intr() handler has not yet
  * been installed. And when in EH we may have released the ST DMA interrupt.
  */
 
 static void do_reset(struct Scsi_Host *instance)
 {
     struct NCR5380_hostdata __maybe_unused *hostdata = shost_priv(instance);
     unsigned long flags;
 
     local_irq_save(flags);
     NCR5380_write(TARGET_COMMAND_REG,
                   PHASE_SR_TO_TCR(NCR5380_read(STATUS_REG) & PHASE_MASK));
     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_RST);
     udelay(50);
     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
     (void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
     local_irq_restore(flags);
 }
 
 /**
  * do_abort - abort the currently established nexus by going to
  * MESSAGE OUT phase and sending an ABORT message.
  * @instance: relevant scsi host instance
  * @can_sleep: 1 or 0 when sleeping is permitted or not, respectively
  *
  * Returns 0 on success, negative error code on failure.
  */
 
 static int do_abort(struct Scsi_Host *instance, unsigned int can_sleep)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     unsigned char *msgptr, phase, tmp;
     int len;
     int rc;
 
     /* Request message out phase */
     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
 
     /*
      * Wait for the target to indicate a valid phase by asserting
      * REQ.  Once this happens, we'll have either a MSGOUT phase
      * and can immediately send the ABORT message, or we'll have some
      * other phase and will have to source/sink data.
      *
      * We really don't care what value was on the bus or what value
      * the target sees, so we just handshake.
      */
 
     rc = NCR5380_poll_politely(hostdata, STATUS_REG, SR_REQ, SR_REQ,
                    10 * HZ * can_sleep);
     if (rc < 0)
         goto out;
 
     tmp = NCR5380_read(STATUS_REG) & PHASE_MASK;
 
     NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(tmp));
 
     if (tmp != PHASE_MSGOUT) {
         NCR5380_write(INITIATOR_COMMAND_REG,
                       ICR_BASE | ICR_ASSERT_ATN | ICR_ASSERT_ACK);
         rc = NCR5380_poll_politely(hostdata, STATUS_REG, SR_REQ, 0,
                        3 * HZ * can_sleep);
         if (rc < 0)
             goto out;
         NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
     }
 
     tmp = ABORT;
     msgptr = &tmp;
     len = 1;
     phase = PHASE_MSGOUT;
     NCR5380_transfer_pio(instance, &phase, &len, &msgptr, can_sleep);
     if (len)
         rc = -ENXIO;
 
     /*
      * If we got here, and the command completed successfully,
      * we're about to go into bus free state.
      */
 
 out:
     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
     return rc;
 }
 
 /*
  * Function : int NCR5380_transfer_dma (struct Scsi_Host *instance,
  * unsigned char *phase, int *count, unsigned char **data)
  *
  * Purpose : transfers data in given phase using either real
  * or pseudo DMA.
  *
  * Inputs : instance - instance of driver, *phase - pointer to
  * what phase is expected, *count - pointer to number of
  * bytes to transfer, **data - pointer to data pointer.
  *
  * Returns : -1 when different phase is entered without transferring
  * maximum number of bytes, 0 if all bytes or transferred or exit
  * is in same phase.
  *
  * Also, *phase, *count, *data are modified in place.
  */
 
 
 static int NCR5380_transfer_dma(struct Scsi_Host *instance,
                 unsigned char *phase, int *count,
                 unsigned char **data)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     int c = *count;
     unsigned char p = *phase;
     unsigned char *d = *data;
     unsigned char tmp;
     int result = 0;
 
     if ((tmp = (NCR5380_read(STATUS_REG) & PHASE_MASK)) != p) {
         *phase = tmp;
         return -1;
     }
 
     NCR5380_to_ncmd(hostdata->connected)->phase = p;
 
     if (p & SR_IO) {
         if (hostdata->read_overruns)
             c -= hostdata->read_overruns;
         else if (hostdata->flags & FLAG_DMA_FIXUP)
             --c;
     }
 
     dsprintk(NDEBUG_DMA, instance, "initializing DMA %s: length %d, address %p\n",
              (p & SR_IO) ? "receive" : "send", c, d);
 
 #ifdef CONFIG_SUN3
     /* send start chain */
     sun3scsi_dma_start(c, *data);
 #endif
 
     NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(p));
     NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE | MR_MONITOR_BSY |
                             MR_ENABLE_EOP_INTR);
 
     if (!(hostdata->flags & FLAG_LATE_DMA_SETUP)) {
         /* On the Medusa, it is a must to initialize the DMA before
          * starting the NCR. This is also the cleaner way for the TT.
          */
         if (p & SR_IO)
             result = NCR5380_dma_recv_setup(hostdata, d, c);
         else
             result = NCR5380_dma_send_setup(hostdata, d, c);
     }
 
     /*
      * On the PAS16 at least I/O recovery delays are not needed here.
      * Everyone else seems to want them.
      */
 
     if (p & SR_IO) {
         NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
         NCR5380_io_delay(1);
         NCR5380_write(START_DMA_INITIATOR_RECEIVE_REG, 0);
     } else {
         NCR5380_io_delay(1);
         NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_DATA);
         NCR5380_io_delay(1);
         NCR5380_write(START_DMA_SEND_REG, 0);
         NCR5380_io_delay(1);
     }
 
 #ifdef CONFIG_SUN3
 #ifdef SUN3_SCSI_VME
     dregs->csr |= CSR_DMA_ENABLE;
 #endif
     sun3_dma_active = 1;
 #endif
 
     if (hostdata->flags & FLAG_LATE_DMA_SETUP) {
         /* On the Falcon, the DMA setup must be done after the last
          * NCR access, else the DMA setup gets trashed!
          */
         if (p & SR_IO)
             result = NCR5380_dma_recv_setup(hostdata, d, c);
         else
             result = NCR5380_dma_send_setup(hostdata, d, c);
     }
 
     /* On failure, NCR5380_dma_xxxx_setup() returns a negative int. */
     if (result < 0)
         return result;
 
     /* For real DMA, result is the byte count. DMA interrupt is expected. */
     if (result > 0) {
         hostdata->dma_len = result;
         return 0;
     }
 
     /* The result is zero iff pseudo DMA send/receive was completed. */
     hostdata->dma_len = c;
 
 /*
  * A note regarding the DMA errata workarounds for early NMOS silicon.
  *
  * For DMA sends, we want to wait until the last byte has been
  * transferred out over the bus before we turn off DMA mode.  Alas, there
  * seems to be no terribly good way of doing this on a 5380 under all
  * conditions.  For non-scatter-gather operations, we can wait until REQ
  * and ACK both go false, or until a phase mismatch occurs.  Gather-sends
  * are nastier, since the device will be expecting more data than we
  * are prepared to send it, and REQ will remain asserted.  On a 53C8[01] we
  * could test Last Byte Sent to assure transfer (I imagine this is precisely
  * why this signal was added to the newer chips) but on the older 538[01]
  * this signal does not exist.  The workaround for this lack is a watchdog;
  * we bail out of the wait-loop after a modest amount of wait-time if
  * the usual exit conditions are not met.  Not a terribly clean or
  * correct solution :-%
  *
  * DMA receive is equally tricky due to a nasty characteristic of the NCR5380.
  * If the chip is in DMA receive mode, it will respond to a target's
  * REQ by latching the SCSI data into the INPUT DATA register and asserting
  * ACK, even if it has _already_ been notified by the DMA controller that
  * the current DMA transfer has completed!  If the NCR5380 is then taken
  * out of DMA mode, this already-acknowledged byte is lost. This is
  * not a problem for "one DMA transfer per READ command", because
  * the situation will never arise... either all of the data is DMA'ed
  * properly, or the target switches to MESSAGE IN phase to signal a
  * disconnection (either operation bringing the DMA to a clean halt).
  * However, in order to handle scatter-receive, we must work around the
  * problem.  The chosen fix is to DMA fewer bytes, then check for the
  * condition before taking the NCR5380 out of DMA mode.  One or two extra
  * bytes are transferred via PIO as necessary to fill out the original
  * request.
  */
 
     if (hostdata->flags & FLAG_DMA_FIXUP) {
         if (p & SR_IO) {
             /*
              * The workaround was to transfer fewer bytes than we
              * intended to with the pseudo-DMA read function, wait for
              * the chip to latch the last byte, read it, and then disable
              * pseudo-DMA mode.
              *
              * After REQ is asserted, the NCR5380 asserts DRQ and ACK.
              * REQ is deasserted when ACK is asserted, and not reasserted
              * until ACK goes false.  Since the NCR5380 won't lower ACK
              * until DACK is asserted, which won't happen unless we twiddle
              * the DMA port or we take the NCR5380 out of DMA mode, we
              * can guarantee that we won't handshake another extra
              * byte.
              */
 
             if (NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG,
                                       BASR_DRQ, BASR_DRQ, 0) < 0) {
                 result = -1;
                 shost_printk(KERN_ERR, instance, "PDMA read: DRQ timeout\n");
             }
             if (NCR5380_poll_politely(hostdata, STATUS_REG,
                                       SR_REQ, 0, 0) < 0) {
                 result = -1;
                 shost_printk(KERN_ERR, instance, "PDMA read: !REQ timeout\n");
             }
             d[*count - 1] = NCR5380_read(INPUT_DATA_REG);
         } else {
             /*
              * Wait for the last byte to be sent.  If REQ is being asserted for
              * the byte we're interested, we'll ACK it and it will go false.
              */
             if (NCR5380_poll_politely2(hostdata,
                  BUS_AND_STATUS_REG, BASR_DRQ, BASR_DRQ,
                  BUS_AND_STATUS_REG, BASR_PHASE_MATCH, 0, 0) < 0) {
                 result = -1;
                 shost_printk(KERN_ERR, instance, "PDMA write: DRQ and phase timeout\n");
             }
         }
     }
 
     NCR5380_dma_complete(instance);
     return result;
 }
 
 /*
  * Function : NCR5380_information_transfer (struct Scsi_Host *instance)
  *
  * Purpose : run through the various SCSI phases and do as the target
  * directs us to.  Operates on the currently connected command,
  * instance->connected.
  *
  * Inputs : instance, instance for which we are doing commands
  *
  * Side effects : SCSI things happen, the disconnected queue will be
  * modified if a command disconnects, *instance->connected will
  * change.
  *
  * XXX Note : we need to watch for bus free or a reset condition here
  * to recover from an unexpected bus free condition.
  */
 
 static void NCR5380_information_transfer(struct Scsi_Host *instance)
     __releases(&hostdata->lock) __acquires(&hostdata->lock)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     unsigned char msgout = NOP;
     int sink = 0;
     int len;
     int transfersize;
     unsigned char *data;
     unsigned char phase, tmp, extended_msg[10], old_phase = 0xff;
     struct scsi_cmnd *cmd;
 
 #ifdef SUN3_SCSI_VME
     dregs->csr |= CSR_INTR;
 #endif
 
     while ((cmd = hostdata->connected)) {
         struct NCR5380_cmd *ncmd = NCR5380_to_ncmd(cmd);
 
         tmp = NCR5380_read(STATUS_REG);
         /* We only have a valid SCSI phase when REQ is asserted */
         if (tmp & SR_REQ) {
             phase = (tmp & PHASE_MASK);
             if (phase != old_phase) {
                 old_phase = phase;
                 NCR5380_dprint_phase(NDEBUG_INFORMATION, instance);
             }
 #ifdef CONFIG_SUN3
             if (phase == PHASE_CMDOUT &&
                 sun3_dma_setup_done != cmd) {
                 int count;
 
                 advance_sg_buffer(ncmd);
 
                 count = sun3scsi_dma_xfer_len(hostdata, cmd);
 
                 if (count > 0) {
                     if (cmd->sc_data_direction == DMA_TO_DEVICE)
                         sun3scsi_dma_send_setup(hostdata,
                                     ncmd->ptr, count);
                     else
                         sun3scsi_dma_recv_setup(hostdata,
                                     ncmd->ptr, count);
                     sun3_dma_setup_done = cmd;
                 }
 #ifdef SUN3_SCSI_VME
                 dregs->csr |= CSR_INTR;
 #endif
             }
 #endif /* CONFIG_SUN3 */
 
             if (sink && (phase != PHASE_MSGOUT)) {
                 NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(tmp));
 
                 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN |
                               ICR_ASSERT_ACK);
                 while (NCR5380_read(STATUS_REG) & SR_REQ)
                     ;
                 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE |
                               ICR_ASSERT_ATN);
                 sink = 0;
                 continue;
             }
 
             switch (phase) {
             case PHASE_DATAOUT:
 #if (NDEBUG & NDEBUG_NO_DATAOUT)
                 shost_printk(KERN_DEBUG, instance, "NDEBUG_NO_DATAOUT set, attempted DATAOUT aborted\n");
                 sink = 1;
                 do_abort(instance, 0);
                 cmd->result = DID_ERROR << 16;
                 complete_cmd(instance, cmd);
                 hostdata->connected = NULL;
                 hostdata->busy[scmd_id(cmd)] &= ~(1 << cmd->device->lun);
                 return;
 #endif
             case PHASE_DATAIN:
                 /*
                  * If there is no room left in the current buffer in the
                  * scatter-gather list, move onto the next one.
                  */
 
                 advance_sg_buffer(ncmd);
                 dsprintk(NDEBUG_INFORMATION, instance,
                     "this residual %d, sg ents %d\n",
                     ncmd->this_residual,
                     sg_nents(ncmd->buffer));
 
                 /*
                  * The preferred transfer method is going to be
                  * PSEUDO-DMA for systems that are strictly PIO,
                  * since we can let the hardware do the handshaking.
                  *
                  * For this to work, we need to know the transfersize
                  * ahead of time, since the pseudo-DMA code will sit
                  * in an unconditional loop.
                  */
 
                 transfersize = 0;
                 if (!cmd->device->borken)
                     transfersize = NCR5380_dma_xfer_len(hostdata, cmd);
 
                 if (transfersize > 0) {
                     len = transfersize;
                     if (NCR5380_transfer_dma(instance, &phase,
                         &len, (unsigned char **)&ncmd->ptr)) {
                         /*
                          * If the watchdog timer fires, all future
                          * accesses to this device will use the
                          * polled-IO.
                          */
                         scmd_printk(KERN_INFO, cmd,
                             "switching to slow handshake\n");
                         cmd->device->borken = 1;
                         do_reset(instance);
                         bus_reset_cleanup(instance);
                     }
                 } else {
                     /* Transfer a small chunk so that the
                      * irq mode lock is not held too long.
                      */
                     transfersize = min(ncmd->this_residual,
                                NCR5380_PIO_CHUNK_SIZE);
                     len = transfersize;
                     NCR5380_transfer_pio(instance, &phase, &len,
                                  (unsigned char **)&ncmd->ptr,
                                  0);
                     ncmd->this_residual -= transfersize - len;
                 }
 #ifdef CONFIG_SUN3
                 if (sun3_dma_setup_done == cmd)
                     sun3_dma_setup_done = NULL;
 #endif
                 return;
             case PHASE_MSGIN:
                 len = 1;
                 data = &tmp;
                 NCR5380_transfer_pio(instance, &phase, &len, &data, 0);
                 ncmd->message = tmp;
 
                 switch (tmp) {
                 case ABORT:
                     set_host_byte(cmd, DID_ABORT);
                     fallthrough;
                 case COMMAND_COMPLETE:
                     /* Accept message by clearing ACK */
                     sink = 1;
                     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                     dsprintk(NDEBUG_QUEUES, instance,
                              "COMMAND COMPLETE %p target %d lun %llu\n",
                              cmd, scmd_id(cmd), cmd->device->lun);
 
                     hostdata->connected = NULL;
                     hostdata->busy[scmd_id(cmd)] &= ~(1 << cmd->device->lun);
 
                     set_status_byte(cmd, ncmd->status);
 
                     set_resid_from_SCp(cmd);
 
                     if (cmd->cmnd[0] == REQUEST_SENSE)
                         complete_cmd(instance, cmd);
                     else {
                         if (ncmd->status == SAM_STAT_CHECK_CONDITION ||
                             ncmd->status == SAM_STAT_COMMAND_TERMINATED) {
                             dsprintk(NDEBUG_QUEUES, instance, "autosense: adding cmd %p to tail of autosense queue\n",
                                      cmd);
                             list_add_tail(&ncmd->list,
                                           &hostdata->autosense);
                         } else
                             complete_cmd(instance, cmd);
                     }
 
                     /*
                      * Restore phase bits to 0 so an interrupted selection,
                      * arbitration can resume.
                      */
                     NCR5380_write(TARGET_COMMAND_REG, 0);
 
                     return;
                 case MESSAGE_REJECT:
                     /* Accept message by clearing ACK */
                     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                     switch (hostdata->last_message) {
                     case HEAD_OF_QUEUE_TAG:
                     case ORDERED_QUEUE_TAG:
                     case SIMPLE_QUEUE_TAG:
                         cmd->device->simple_tags = 0;
                         hostdata->busy[cmd->device->id] |= (1 << (cmd->device->lun & 0xFF));
                         break;
                     default:
                         break;
                     }
                     break;
                 case DISCONNECT:
                     /* Accept message by clearing ACK */
                     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                     hostdata->connected = NULL;
                     list_add(&ncmd->list, &hostdata->disconnected);
                     dsprintk(NDEBUG_INFORMATION | NDEBUG_QUEUES,
                              instance, "connected command %p for target %d lun %llu moved to disconnected queue\n",
                              cmd, scmd_id(cmd), cmd->device->lun);
 
                     /*
                      * Restore phase bits to 0 so an interrupted selection,
                      * arbitration can resume.
                      */
                     NCR5380_write(TARGET_COMMAND_REG, 0);
 
 #ifdef SUN3_SCSI_VME
                     dregs->csr |= CSR_DMA_ENABLE;
 #endif
                     return;
                     /*
                      * The SCSI data pointer is *IMPLICITLY* saved on a disconnect
                      * operation, in violation of the SCSI spec so we can safely
                      * ignore SAVE/RESTORE pointers calls.
                      *
                      * Unfortunately, some disks violate the SCSI spec and
                      * don't issue the required SAVE_POINTERS message before
                      * disconnecting, and we have to break spec to remain
                      * compatible.
                      */
                 case SAVE_POINTERS:
                 case RESTORE_POINTERS:
                     /* Accept message by clearing ACK */
                     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                     break;
                 case EXTENDED_MESSAGE:
                     /*
                      * Start the message buffer with the EXTENDED_MESSAGE
                      * byte, since spi_print_msg() wants the whole thing.
                      */
                     extended_msg[0] = EXTENDED_MESSAGE;
                     /* Accept first byte by clearing ACK */
                     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
 
                     spin_unlock_irq(&hostdata->lock);
 
                     dsprintk(NDEBUG_EXTENDED, instance, "receiving extended message\n");
 
                     len = 2;
                     data = extended_msg + 1;
                     phase = PHASE_MSGIN;
                     NCR5380_transfer_pio(instance, &phase, &len, &data, 1);
                     dsprintk(NDEBUG_EXTENDED, instance, "length %d, code 0x%02x\n",
                              (int)extended_msg[1],
                              (int)extended_msg[2]);
 
                     if (!len && extended_msg[1] > 0 &&
                         extended_msg[1] <= sizeof(extended_msg) - 2) {
                         /* Accept third byte by clearing ACK */
                         NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                         len = extended_msg[1] - 1;
                         data = extended_msg + 3;
                         phase = PHASE_MSGIN;
 
                         NCR5380_transfer_pio(instance, &phase, &len, &data, 1);
                         dsprintk(NDEBUG_EXTENDED, instance, "message received, residual %d\n",
                                  len);
 
                         switch (extended_msg[2]) {
                         case EXTENDED_SDTR:
                         case EXTENDED_WDTR:
                             tmp = 0;
                         }
                     } else if (len) {
                         shost_printk(KERN_ERR, instance, "error receiving extended message\n");
                         tmp = 0;
                     } else {
                         shost_printk(KERN_NOTICE, instance, "extended message code %02x length %d is too long\n",
                                      extended_msg[2], extended_msg[1]);
                         tmp = 0;
                     }
 
                     spin_lock_irq(&hostdata->lock);
                     if (!hostdata->connected)
                         return;
 
                     /* Reject message */
                     fallthrough;
                 default:
                     /*
                      * If we get something weird that we aren't expecting,
                      * log it.
                      */
                     if (tmp == EXTENDED_MESSAGE)
                         scmd_printk(KERN_INFO, cmd,
                                     "rejecting unknown extended message code %02x, length %d\n",
                                     extended_msg[2], extended_msg[1]);
                     else if (tmp)
                         scmd_printk(KERN_INFO, cmd,
                                     "rejecting unknown message code %02x\n",
                                     tmp);
 
                     msgout = MESSAGE_REJECT;
                     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
                     break;
                 } /* switch (tmp) */
                 break;
             case PHASE_MSGOUT:
                 len = 1;
                 data = &msgout;
                 hostdata->last_message = msgout;
                 NCR5380_transfer_pio(instance, &phase, &len, &data, 0);
                 if (msgout == ABORT) {
                     hostdata->connected = NULL;
                     hostdata->busy[scmd_id(cmd)] &= ~(1 << cmd->device->lun);
                     cmd->result = DID_ERROR << 16;
                     complete_cmd(instance, cmd);
                     return;
                 }
                 msgout = NOP;
                 break;
             case PHASE_CMDOUT:
                 len = cmd->cmd_len;
                 data = cmd->cmnd;
                 /*
                  * XXX for performance reasons, on machines with a
                  * PSEUDO-DMA architecture we should probably
                  * use the dma transfer function.
                  */
                 NCR5380_transfer_pio(instance, &phase, &len, &data, 0);
                 break;
             case PHASE_STATIN:
                 len = 1;
                 data = &tmp;
                 NCR5380_transfer_pio(instance, &phase, &len, &data, 0);
                 ncmd->status = tmp;
                 break;
             default:
                 shost_printk(KERN_ERR, instance, "unknown phase\n");
                 NCR5380_dprint(NDEBUG_ANY, instance);
             } /* switch(phase) */
         } else {
             spin_unlock_irq(&hostdata->lock);
             NCR5380_poll_politely(hostdata, STATUS_REG, SR_REQ, SR_REQ, HZ);
             spin_lock_irq(&hostdata->lock);
         }
     }
 }
 
 /*
  * Function : void NCR5380_reselect (struct Scsi_Host *instance)
  *
  * Purpose : does reselection, initializing the instance->connected
  * field to point to the scsi_cmnd for which the I_T_L or I_T_L_Q
  * nexus has been reestablished,
  *
  * Inputs : instance - this instance of the NCR5380.
  */
 
 static void NCR5380_reselect(struct Scsi_Host *instance)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     unsigned char target_mask;
     unsigned char lun;
     unsigned char msg[3];
     struct NCR5380_cmd *ncmd;
     struct scsi_cmnd *tmp;
 
     /*
      * Disable arbitration, etc. since the host adapter obviously
      * lost, and tell an interrupted NCR5380_select() to restart.
      */
 
     NCR5380_write(MODE_REG, MR_BASE);
 
     target_mask = NCR5380_read(CURRENT_SCSI_DATA_REG) & ~(hostdata->id_mask);
     if (!target_mask || target_mask & (target_mask - 1)) {
         shost_printk(KERN_WARNING, instance,
                  "reselect: bad target_mask 0x%02x\n", target_mask);
         return;
     }
 
     /*
      * At this point, we have detected that our SCSI ID is on the bus,
      * SEL is true and BSY was false for at least one bus settle delay
      * (400 ns).
      *
      * We must assert BSY ourselves, until the target drops the SEL
      * signal.
      */
 
     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_BSY);
     if (NCR5380_poll_politely(hostdata,
                               STATUS_REG, SR_SEL, 0, 0) < 0) {
         shost_printk(KERN_ERR, instance, "reselect: !SEL timeout\n");
         NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
         return;
     }
     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
 
     /*
      * Wait for target to go into MSGIN.
      */
 
     if (NCR5380_poll_politely(hostdata,
                               STATUS_REG, SR_REQ, SR_REQ, 0) < 0) {
         if ((NCR5380_read(STATUS_REG) & (SR_BSY | SR_SEL)) == 0)
             /* BUS FREE phase */
             return;
         shost_printk(KERN_ERR, instance, "reselect: REQ timeout\n");
         do_abort(instance, 0);
         return;
     }
 
 #ifdef CONFIG_SUN3
     /* acknowledge toggle to MSGIN */
     NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(PHASE_MSGIN));
 
     /* peek at the byte without really hitting the bus */
     msg[0] = NCR5380_read(CURRENT_SCSI_DATA_REG);
 #else
     {
         int len = 1;
         unsigned char *data = msg;
         unsigned char phase = PHASE_MSGIN;
 
         NCR5380_transfer_pio(instance, &phase, &len, &data, 0);
 
         if (len) {
             do_abort(instance, 0);
             return;
         }
     }
 #endif /* CONFIG_SUN3 */
 
     if (!(msg[0] & 0x80)) {
         shost_printk(KERN_ERR, instance, "expecting IDENTIFY message, got ");
         spi_print_msg(msg);
         printk("\n");
         do_abort(instance, 0);
         return;
     }
     lun = msg[0] & 0x07;
 
     /*
      * We need to add code for SCSI-II to track which devices have
      * I_T_L_Q nexuses established, and which have simple I_T_L
      * nexuses so we can chose to do additional data transfer.
      */
 
     /*
      * Find the command corresponding to the I_T_L or I_T_L_Q  nexus we
      * just reestablished, and remove it from the disconnected queue.
      */
 
     tmp = NULL;
     list_for_each_entry(ncmd, &hostdata->disconnected, list) {
         struct scsi_cmnd *cmd = NCR5380_to_scmd(ncmd);
 
         if (target_mask == (1 << scmd_id(cmd)) &&
             lun == (u8)cmd->device->lun) {
             list_del(&ncmd->list);
             tmp = cmd;
             break;
         }
     }
 
     if (tmp) {
         dsprintk(NDEBUG_RESELECTION | NDEBUG_QUEUES, instance,
                  "reselect: removed %p from disconnected queue\n", tmp);
     } else {
         int target = ffs(target_mask) - 1;
 
         shost_printk(KERN_ERR, instance, "target bitmask 0x%02x lun %d not in disconnected queue.\n",
                      target_mask, lun);
         /*
          * Since we have an established nexus that we can't do anything
          * with, we must abort it.
          */
         if (do_abort(instance, 0) == 0)
             hostdata->busy[target] &= ~(1 << lun);
         return;
     }
 
 #ifdef CONFIG_SUN3
     if (sun3_dma_setup_done != tmp) {
         int count;
 
         advance_sg_buffer(ncmd);
 
         count = sun3scsi_dma_xfer_len(hostdata, tmp);
 
         if (count > 0) {
             if (tmp->sc_data_direction == DMA_TO_DEVICE)
                 sun3scsi_dma_send_setup(hostdata,
                             ncmd->ptr, count);
             else
                 sun3scsi_dma_recv_setup(hostdata,
                             ncmd->ptr, count);
             sun3_dma_setup_done = tmp;
         }
     }
 
     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ACK);
 #endif /* CONFIG_SUN3 */
 
     /* Accept message by clearing ACK */
     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
 
     hostdata->connected = tmp;
     dsprintk(NDEBUG_RESELECTION, instance, "nexus established, target %d, lun %llu\n",
              scmd_id(tmp), tmp->device->lun);
 }
 
 /**
  * list_find_cmd - test for presence of a command in a linked list
  * @haystack: list of commands
  * @needle: command to search for
  */
 
 static bool list_find_cmd(struct list_head *haystack,
                           struct scsi_cmnd *needle)
 {
     struct NCR5380_cmd *ncmd;
 
     list_for_each_entry(ncmd, haystack, list)
         if (NCR5380_to_scmd(ncmd) == needle)
             return true;
     return false;
 }
 
 /**
  * list_remove_cmd - remove a command from linked list
  * @haystack: list of commands
  * @needle: command to remove
  */
 
 static bool list_del_cmd(struct list_head *haystack,
                          struct scsi_cmnd *needle)
 {
     if (list_find_cmd(haystack, needle)) {
         struct NCR5380_cmd *ncmd = NCR5380_to_ncmd(needle);
 
         list_del(&ncmd->list);
         return true;
     }
     return false;
 }
 
 /**
  * NCR5380_abort - scsi host eh_abort_handler() method
  * @cmd: the command to be aborted
  *
  * Try to abort a given command by removing it from queues and/or sending
  * the target an abort message. This may not succeed in causing a target
  * to abort the command. Nonetheless, the low-level driver must forget about
  * the command because the mid-layer reclaims it and it may be re-issued.
  *
  * The normal path taken by a command is as follows. For EH we trace this
  * same path to locate and abort the command.
  *
  * unissued -> selecting -> [unissued -> selecting ->]... connected ->
  * [disconnected -> connected ->]...
  * [autosense -> connected ->] done
  *
  * If cmd was not found at all then presumably it has already been completed,
  * in which case return SUCCESS to try to avoid further EH measures.
  *
  * If the command has not completed yet, we must not fail to find it.
  * We have no option but to forget the aborted command (even if it still
  * lacks sense data). The mid-layer may re-issue a command that is in error
  * recovery (see scsi_send_eh_cmnd), but the logic and data structures in
  * this driver are such that a command can appear on one queue only.
  *
  * The lock protects driver data structures, but EH handlers also use it
  * to serialize their own execution and prevent their own re-entry.
  */
 
 static int NCR5380_abort(struct scsi_cmnd *cmd)
 {
     struct Scsi_Host *instance = cmd->device->host;
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     unsigned long flags;
     int result = SUCCESS;
 
     spin_lock_irqsave(&hostdata->lock, flags);
 
 #if (NDEBUG & NDEBUG_ANY)
     scmd_printk(KERN_INFO, cmd, __func__);
 #endif
     NCR5380_dprint(NDEBUG_ANY, instance);
     NCR5380_dprint_phase(NDEBUG_ANY, instance);
 
     if (list_del_cmd(&hostdata->unissued, cmd)) {
         dsprintk(NDEBUG_ABORT, instance,
                  "abort: removed %p from issue queue\n", cmd);
         cmd->result = DID_ABORT << 16;
         scsi_done(cmd); /* No tag or busy flag to worry about */
         goto out;
     }
 
     if (hostdata->selecting == cmd) {
         dsprintk(NDEBUG_ABORT, instance,
                  "abort: cmd %p == selecting\n", cmd);
         hostdata->selecting = NULL;
         cmd->result = DID_ABORT << 16;
         complete_cmd(instance, cmd);
         goto out;
     }
 
     if (list_del_cmd(&hostdata->disconnected, cmd)) {
         dsprintk(NDEBUG_ABORT, instance,
                  "abort: removed %p from disconnected list\n", cmd);
         /* Can't call NCR5380_select() and send ABORT because that
          * means releasing the lock. Need a bus reset.
          */
         set_host_byte(cmd, DID_ERROR);
         complete_cmd(instance, cmd);
         result = FAILED;
         goto out;
     }
 
     if (hostdata->connected == cmd) {
         dsprintk(NDEBUG_ABORT, instance, "abort: cmd %p is connected\n", cmd);
         hostdata->connected = NULL;
         hostdata->dma_len = 0;
         if (do_abort(instance, 0) < 0) {
             set_host_byte(cmd, DID_ERROR);
             complete_cmd(instance, cmd);
             result = FAILED;
             goto out;
         }
         set_host_byte(cmd, DID_ABORT);
         complete_cmd(instance, cmd);
         goto out;
     }
 
     if (list_del_cmd(&hostdata->autosense, cmd)) {
         dsprintk(NDEBUG_ABORT, instance,
                  "abort: removed %p from sense queue\n", cmd);
         complete_cmd(instance, cmd);
     }
 
 out:
     if (result == FAILED)
         dsprintk(NDEBUG_ABORT, instance, "abort: failed to abort %p\n", cmd);
     else {
         hostdata->busy[scmd_id(cmd)] &= ~(1 << cmd->device->lun);
         dsprintk(NDEBUG_ABORT, instance, "abort: successfully aborted %p\n", cmd);
     }
 
     queue_work(hostdata->work_q, &hostdata->main_task);
     spin_unlock_irqrestore(&hostdata->lock, flags);
 
     return result;
 }
 
 
 static void bus_reset_cleanup(struct Scsi_Host *instance)
 {
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     int i;
     struct NCR5380_cmd *ncmd;
 
     /* reset NCR registers */
     NCR5380_write(MODE_REG, MR_BASE);
     NCR5380_write(TARGET_COMMAND_REG, 0);
     NCR5380_write(SELECT_ENABLE_REG, 0);
 
     /* After the reset, there are no more connected or disconnected commands
      * and no busy units; so clear the low-level status here to avoid
      * conflicts when the mid-level code tries to wake up the affected
      * commands!
      */
 
     if (hostdata->selecting) {
         hostdata->selecting->result = DID_RESET << 16;
         complete_cmd(instance, hostdata->selecting);
         hostdata->selecting = NULL;
     }
 
     list_for_each_entry(ncmd, &hostdata->disconnected, list) {
         struct scsi_cmnd *cmd = NCR5380_to_scmd(ncmd);
 
         set_host_byte(cmd, DID_RESET);
         complete_cmd(instance, cmd);
     }
     INIT_LIST_HEAD(&hostdata->disconnected);
 
     list_for_each_entry(ncmd, &hostdata->autosense, list) {
         struct scsi_cmnd *cmd = NCR5380_to_scmd(ncmd);
 
         scsi_done(cmd);
     }
     INIT_LIST_HEAD(&hostdata->autosense);
 
     if (hostdata->connected) {
         set_host_byte(hostdata->connected, DID_RESET);
         complete_cmd(instance, hostdata->connected);
         hostdata->connected = NULL;
     }
 
     for (i = 0; i < 8; ++i)
         hostdata->busy[i] = 0;
     hostdata->dma_len = 0;
 
     queue_work(hostdata->work_q, &hostdata->main_task);
 }
 
 /**
  * NCR5380_host_reset - reset the SCSI host
  * @cmd: SCSI command undergoing EH
  *
  * Returns SUCCESS
  */
 
 static int NCR5380_host_reset(struct scsi_cmnd *cmd)
 {
     struct Scsi_Host *instance = cmd->device->host;
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     unsigned long flags;
     struct NCR5380_cmd *ncmd;
 
     spin_lock_irqsave(&hostdata->lock, flags);
 
 #if (NDEBUG & NDEBUG_ANY)
     shost_printk(KERN_INFO, instance, __func__);
 #endif
     NCR5380_dprint(NDEBUG_ANY, instance);
     NCR5380_dprint_phase(NDEBUG_ANY, instance);
 
     list_for_each_entry(ncmd, &hostdata->unissued, list) {
         struct scsi_cmnd *scmd = NCR5380_to_scmd(ncmd);
 
         scmd->result = DID_RESET << 16;
         scsi_done(scmd);
     }
     INIT_LIST_HEAD(&hostdata->unissued);
 
     do_reset(instance);
     bus_reset_cleanup(instance);
 
     spin_unlock_irqrestore(&hostdata->lock, flags);
 
     return SUCCESS;
 }

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